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Mar 12, 2014
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Crypto.Cat: The Chat Site That Protects Your PrivacyPosted on Jul 28, 2012
Lebanese expatriate Nadim Kobeissi, 21, is determined to "subvert governments and frustrate marketers" with a cat- and code-themed website that allows users to exchange messages and files that can't be read by anyone but the sender and receiver. Kobeissi—who endured the loss of loved ones, barely escaped death himself, and knows people who were tortured because they did not protect their online communications—hopes crypto.cat will provide journalists, dissidents and others under surveillance with a secure alternative to such messaging applications as those available on Gmail, Facebook and Skype. With an interface that will be familiar to those who grew up in the decades of 8-bit gaming, Kobeissi also hopes to make his chat client something people will want to use rather than simply need. But he also warns that the program is still in development and should not yet be regarded as completely secure. Watch a fun introduction to crypto.cat made by Kobeissi below. —Posted by Alexander Reed Kelly. Cryptocat Adventure! from Nadim Kobeissi on Vimeo. Advertisement Previous item: Growth Sputters in the Second Quarter Next item: Romney Tells Israel Obama Has Emboldened Its Enemies New and Improved CommentsIf you have trouble leaving a comment, review this help page. Still having problems? Let us know. If you find yourself moderated, take a moment to review our comment policy. |


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Can I give you a quick, "What I Have Learned About Russia Thanks To The Meteor Footage" list?
1. These people listen to crap music.
2. They have very windy roads.
3. It looks cold there, and based on what I know about Russia and World War I, it is.
Russia was hit by a meteor on Friday in the nation's central Ural Mountains, injuring hundreds and causing damage to buildings in six cities, according to reports. Check out this video compilation of it.
Go Science!

subset: commoncrawl


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VitaDigest Supplement Facts | ||
Serving Size: Two (2) Capsules | ||
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Vitamin C (calcium ascorbate) | 120 mg | 200% |
Vitamin D3 | 1000 IU | 250% |
Vitamin E (di-alpha tocopheryl acetate) | 30 IU | 100% |
Thiamin (vitamin B-1, from thiamine HCL) | 3 mg | 200% |
Riboflavin (vitamin B-2) | 3.4 mg | 200% |
Niacin (vitamin B-3, from inositol hexaniacinate) | 20 mg | 100% |
Vitamin B-6 (from pyridoxine HCL) | 10 mg | 500% |
Folic Acid | 5 mg | 1250% |
Vitamin B-12 (from methylcobalamin) | 12 mcg | 200% |
Pantothenic Acid (vitamin B-5, calcium pantothenate) | 5 mg | 50% |
Iron (from iron amino acid chelate) | 35 mg | 194% |
Iodine (from kelp) | 150 mcg | 100% |
Magnesium (from magnesium oxide) | 50 mg | 13% |
Zinc (from zinc amino acid chelate) | 15 mg | 100% |
Copper (from copper amino acid chelate) | 2 mg | 100% |
Lutein | 10 mg | † |
*Percent Daily Values are based on a 2,000 calorie diet. †Daily Value not established. |
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Saturday, May 04, 2013
The Valparaiso women's track and field team posted three top-four finishes from field events on Saturday at the Horizon League Outdoor Championships in Ypsilanti, Mich.
Valparaiso is in fifth place after two days of competition. Milwaukee is in first headed into Sunday's final day of competition.
Sophomore Jazmin Taylor (Rock Island, Ill./Rock Island) finished second in the high jump, clearing 5' 3 ¼".
Junior Kelley Freeman (Valparaiso, Ind./Chesterton) tied for third in the pole vault with a best mark of 10' 10". Freshman Sarah Peters (LaGrange, Ill./Lyons Township) finished tied for sixth.
Sophomore Brooke Hinstorff (Waterloo, Wis./Lakeside Lutheran) placed fourth in the javelin throw with a season-best distance of 110' 5".
On the track, junior Grace Shemwell (Clinton, Iowa/Clinton) finished 10th in the 3000-meter steeplechase with a season-best time of 12:20.54. Freshman Cleo Holt (Marietta, Ga./George Walton Comprehensive) posted a season-best time of 25.98 in the 200-meter dash.
Valparaiso finishes up the final day of competition at the HL Outdoor Championships on Sunday. A link for live stats will be available at www.valpoathletics.com.
Copyright ©2014 Valparaiso University Athletics. All Rights Reserved. | www.ValpoAthletics.com |


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ClassifiedsYour are browsing: Public Notices/Public Notices (682) PUBLIC NOTICEPUBLIC NOTICEHill Country Community Action Association, Inc. Weatherization Program is soliciting bids for the following two subcontracts. 1. Contractor to provide materials and install energy efficiency measures. 2. Mechanical Contractor to repair, install, and provide units for air conditioning and heating measures. The areas covered will include the following counties: Bell, Burnet, Coryell, Erath, Hamilton, Lampasas, Llano, Mason, Milam, Mills, San Saba, Somervell, and Williamson. The bid packets can be obtained by contacting HCCAA, Inc., P.O. Box 846, San Saba, Texas 76877 or calling (325) 372-5167 ext. 282, or at our Central Office located at 2905 West Wallace, San Saba, Texas. A Pre-Bid Conference will be held on, April 3, 2013 at 9:00AM at the San Saba Multi-Service Senior Center located at 705 E. Storey, San Saba, Texas to answer questions from potential bidders. The completed bid must be received in San Saba no later than 8:30 a.m. on, April 15, 2013. Bids will be publicly opened at 9:00 a.m. on Monday, April 15, 2013 at 2905 W. Wallace, San Saba. Only complete packets will be accepted. The final selection process will be competitive sealed bid based on price and other written selection criteria. Hill Country Community Action Association, Inc. reserves the right to refuse any or all bids. The initial contracts will be for one year with an option to renew for an additional four years. Hill Country Community Action Associates, Inc. is an equal opportunity employer. |
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FREE Email Newsletter
Photographers Group Sues Google
April 7, 2010 9:24 pm | by Wall Street Journal | CommentsThe American Society of Media Photographers, as well as several other trade groups, filed a lawsuit claiming that Google's vast digital library would rob them of compensation.
These Warriors Write Computer Code
April 7, 2010 6:24 pm | by Wall Street Journal | CommentsIn Silicon Valley, "Ninja" is the hot new job title, as programmers apply the sly skills of feudal Japanese warriors to writing software.
Answers to Your iPad Questions
April 7, 2010 5:26 pm | by Wall Street Journal | CommentsWalt Mossberg answers common questions about the Apple iPad, from printing to how to handle getting a replacement once the battery dies.
Online Ads Show Signs of Pickup
April 7, 2010 3:25 pm | by Wall Street Journal | CommentsSigns of life are returning to the Internet-ad business after the harshest year since 2002, with a report showing that U.S. online-ad spending started to pick up during the second half of 2009.
NY suit vs. Google seeks damages for pictures, art
April 7, 2010 2:30 pm | by LARRY NEUMEISTER - Associated Press Writer - Associated Press | CommentsGroups representing photographers and artists on Wednesday accused Internet search leader Google of copyright infringement in a lawsuit that mirrors complaints book publishers and authors have made for years about the company's attempt to create the world's largest digital library.The lawsuit,...
IPhone update might address multitasking complaint
April 7, 2010 1:30 pm | by The Associated Press | CommentsTopping the wish list for the iPhone and the iPad: broader ability to run more than one program at a time.Owners of the Apple Inc. devices are hoping to see those changes as part of updates the company is unveiling Thursday in California.The iPhone already allows for some "multitasking," but...
Lawson Software fiscal 3Q profit falls 71 percent
April 7, 2010 1:30 pm | by The Associated Press | CommentsLawson Software Inc. on Wednesday reported a 71 percent drop in its fiscal third-quarter net income as higher costs more than offset an increase in revenue.The business software company earned $1.8 million, or a penny per share, compared with a profit of $6.2 million, or 4 cents per share, in...
Governor: Texas should move to online textbooks
April 7, 2010 1:30 pm | by KELLEY SHANNON - Associated Press Writer - Associated Press | CommentsGov. Rick Perry proposed Wednesday that Texas abandon using traditional textbooks in public schools and replace them with computer technology."I don't see any reason in the world why we need to have textbooks in Texas in the next four years. Do you agree?" Perry asked participants at a computer...
Review: iPad apps cool, but how many will you buy?
April 7, 2010 12:30 pm | by RACHEL METZ - AP Technology Writer - Associated Press | CommentsBecause its large touch screen is interactive and inviting, Apple's iPad offers media companies, game makers and other content providers a way to display material that consumers supposedly will be more likely to pay for.Yet after spending a few days buying and using applications on the iPad,...
Pitt-led study identifies human enzyme that breaks down potentially toxic nanomaterials
April 7, 2010 12:26 pm | by EurekAlert | Comments(University of Pittsburgh) An international study based at the University of Pittsburgh provides the first identification of a human enzyme that can biodegrade carbon nanotubes -- the superstrong materials found in products from electronics to plastics -- and in laboratory tests offset...
Camolyn eye drops, Fisiolin nasal drops: Voluntary recall due to non-sterility
April 7, 2010 12:20 pm | by FDA MedWatch | CommentsLack of sterile product has the potential to cause infections.
Harman Int'l names co-presidents of auto division
April 7, 2010 11:30 am | by The Associated Press | CommentsAudio and entertainment products maker Harman International Industries Inc. said Wednesday it has named two executives to lead its automotive division, replacing Klaus Blickle who is leaving the company.Harman said Sachin Lawande and Michael Mauser will be unit co-presidents and members of the...
SanDisk taps Sumit Sadana for senior VP role
April 7, 2010 11:30 am | by The Associated Press | CommentsSanDisk Corp. named Sumit Sadana as senior vice president of strategy and business development, the flash memory card provider said Wednesday.Sadana previously served as president at Sunrise Capital. In his new role, Sadana will handle strategic planning for all of SanDisk's segments.Sadana...
General Dynamics wins $20 million Boeing contract
April 7, 2010 11:30 am | by The Associated Press | CommentsGeneral Dynamics Corp. said Wednesday it won a $20 million contract from Boeing Co. to make composite parts for military transport planes.General Dynamics said its armament and technical products division received the contract to build components for the C-17 Globemaster III, which the military...
Berkeley Researchers get thin-film OLEDs to emit various colors
April 7, 2010 11:27 am | CommentsUsing polymer nanoparticles, scientists at the Molecular Foundry and the University of California, Berkeley, have made a thin film OLED using iridium-based guest molecules to emit various colors of visible light.


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- The musicians of Grimfells are feeling froggy. So, if we were to learn 4-5 dance numbers would any of you be willing to risk a trip to BOH to dance on andJun 30, 2004View SourceThe musicians of Grimfells are feeling froggy. So, if we were to learn
4-5 dance numbers would any of you be willing to risk a trip to BOH to
dance on and off all day? Not talking ball, just dancing off and on as
the day progresses, and as the players are available. (We will want to
play some none dance things just for the fun of playing.) Some of our
musicians will also be fighting and shooting at different times.
(Conrad, you were born to be a Quick) But if we chose 4-5 dance pieces
we could do them multiple times to get enough good dancing and playing in
during the day. Any none Grimfellions musicians would be welcome in the pit
of course. Right now the Grim-Players have been having a lot of fun with
the Karabushka. (plus a few jigs and a sweet piece called Rose in the
Heather.) We could learn some other pieces at suggestion.
BOH is a very loose and fun event as it is now. It has successfully
incorporated Iron Chef, Horses, a renfair and a really nice music pit last
year. I think it would be nice to add some dancing and formal music.
Pav - My list matces exactly with Tsire s. I am not sure what that means. Oh and I would add Causelle or any other basse dance Seonaid ... top five ... just aboutJul 20, 2004View SourceMy list matces exactly with Tsire's. I am not sure what that means.
Oh and I would add Causelle or any other basse dance
--- In firstname.lastname@example.com, "Tsire Tuzevo" <tsire@h...>
wrote:> Keep the favorites comming - I love to hear what eveyone digs!
top five
> I dig so many dances and have such a short attention span that my
> are contantly changing. But really I'll dance just about anything
just about
> anywhere. (Fox trot, or polka anyone?) For a good list of dances of
> types and popularities wrestle the Pensic Pile off of someone or go
> Pensic and pick up your own!
> Just for fun heres a list of what I really dig at this moment:
> 16th C. Italian Maravigllia and Gracca Amorosa,
> 15th C. Italian Contrapasso in Due and Gratioza,
> ECD: Picking of Sticks and Black Nag
> SCA Corrographies: Heralds in Love
> Bransles: Bransle Charlotte
> Gresley: Ly Bens Dystonis and Perns in Gre
> Old Measures: Black Alman, Lorraine Alman
> Progression: My Lady Cullen
> Guilty Out of Period Pleaures: John Tallows Cannon, Female Sailor,
> Korrobushka
> Tsire
> _________________________________________________________________
> FREE pop-up blocking with the new MSN Toolbar get it now!
> http://toolbar.msn.click-url.com/go/onm00200415ave/direct/01/


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Mason Crest Elementary School Back to School Night
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I was very proud to speak at the first Back to School Night at the new Mason Crest Elementary School. As the Mason District School Board Member, I started working with the community 8 years ago to build this desperately needed school. The sign is the yard sign we used to promote voting for the school's planning money on the school bond referendum. Evidence that persistence and hard work pays off!
Kaye and Terry McAuliffe
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Kaye and JEB Stuart students
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Kaye visits Triway
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Latest News


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A collection of news and information related to Nick Lachey published by this site and its partners.
Top Nick Lachey Articles
Displaying items 67-77
Rachel Weisz, director Darren Aronofsky have split
Story | Nov 9, 2010 | 4:32 PMActress Rachel Weisz and her partner of nine years, director Darren Aronofsky, split months ago, their reps have confirmed with several media outlets. The couple, who got engaged in 2005 but never married, have a son, Henry, who was born...... -
Nick Lachey and Vanessa Minnillo are engaged
Story | Nov 4, 2010 | 4:32 PMNick Lachey and Vanessa Minnillo are engaged, he confirmed Thursday on Twitter. "If anyone's heard the rumors of my engagement, they are absolutely true! Vanessa and I couldn't be happier," he wrote. "Thanks for all the love." Lachey reportedly popped....... -
Justin Berfield sells Calabasas home
'The Sing-Off': Nick Lachey hosts as voices rise
Story | Dec 3, 2010 | 7:47 AMOn Monday, Dec. 6, as holiday music pops up on street corners and in malls, NBC celebrates the power of singing with the premiere of the sophomore season of the a cappella group competition "The Sing-Off." Former 98 Degrees member Nick Lachey is host... -
Wednesday, January 12, 2011
Story | Jan 12, 20115 a.m. Wrap It Up by Sam & Dave Kiss Them For Me by Siouxie & The Banshees Redundant by Green Day Real Wild Child by Iggy Pop I Miss You by Blink 182 You Don't Know How It Feels To Be Me by Tom Petty & The Heartbreakers Funky Town... -
Famous faces take center stage in Independence Day specials
Story | Jun 29, 2011 | 7:43 AMWhat do an actor who plays a popular teacher, another actor famous for portraying a tough cop, and a former boy-band member have in common? They'll all celebrate America's 235th birthday in big cities and very visible ways Monday, July 4. "Glee" co-star... -
Cupcakes are her calling
Sara Bareilles judges with love on 'The Sing-Off'
Chicago's top celebrity hangouts in 2011
'Kourtney and Kim Take New York' recap: Season finale
From cupcakes to cocktails, everyone is crushing on red velvet
Story | Feb 7, 2012Jackie of Baltimore wants the recipe for a red velvet cake: "Two years ago at Christmas, I had the chance to taste this cake but I can't find a recipe anywhere." — Baltimore Sun recipe finder, 1990 Hang in there, Jackie. If you managed to wait...


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Manufactured to reduce exhaust sounds, the Oldsmobile Bravada muffler is composed of numerous tubes that bounce off and muffle sound waves. Driving a car without using a muffler is similar to driving around a tractor; you'll likely enjoy unwanted attention because of the racket your car is creating. Because a car with a busted muffler adds to noise pollution, rules were formulated regarding the proper use of this accessory.
Keeping your car's muffler up and working basically requires regular check-ups. You should be on the lookout for dents and other forms of damage. Subtle symptoms are billowing smoke coming from the tube, and an auto engine that regularly overheats. For a surefire method of finding out what the trouble is, examine this part, or have your automobile checked by an auto repair guy.
If you do need a replacement muffler, you don't need to search far and wide. Our website sells only top-grade components in the market. Available at discounted rates, our parts will definitely fit your limited budget. Along with our low price guarantee as well as Oldsmobile Bravada muffler manufacturers such as Replacement, Starla, and Ansa Sport, you're guaranteed to enjoy the best deal for your dollars.
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Houston's On-Line Country Community
Hi, (not you?) | Member Center | Sign Out
Posted: 3:15 p.m. Tuesday, July 2, 2013
Avril Lavigne and Nickleback frontman Chad Kroeger got married in the most romantic spot in the world — the south of France, RumorFix has confirmed.
The Canadian couple got married on Monday — almost a year after they started dating — at the Chateau de la Napoule, a medieval castle near Cannes.
The candlelight ceremony was the highlight of a three-day celebration.
"I wanted to make sure it's a crazy vacation and an experience of a lifetime for our guests," Avril, who wore a black tulle Monique Lhuillier gown, told HELLO!
Last year, after the rockers spent a week in Paris, Chad gave Avril a 14-carat diamond ring . "It was very natural. We were friends having a good time and then it just happened," Avril told HELLO!.
A romantic Chad said, "It felt like fate was intervening and I was just being given this wake-up call: don't let this one get away."
"We hope to be together forever," Avril added. "One day down the road we'll have a family. I look forward to growing with Chad."
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Copyright © 2008 Elsevier Inc. All rights reserved.
Cell Stem Cell, Volume 2, Issue 1, 39-49, 10 January 2008
Add/View Comments (0)Differentiation-Defective Stem Cells Outcompete Normal Stem Cells for Niche Occupancy in the Drosophila Ovary
Zhigang Jin1, 3, Daniel Kirilly1, 2, 3, Changjiang Weng1, Eihachiro Kawase1, Xiaoqing Song1, Sarah Smith1, Joel Schwartz1 and Ting Xie1, 2, ,
1 Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA
2 Department of Anatomy and Cell Biology, University of Kansas School of Medicine, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
3 These authors contributed equally to this work.
- Rapid progress has recently been made regarding how the niche controls stem cell function, but little is yet known about how stem cells in the same niche interact with one another. In this study, we show that differentiation-defective Drosophila ovarian germline stem cells (GSCs) can outcompete normal ones for niche occupancy in a cadherin-dependent manner. The differentiation-defective bam or bgcn mutant GSCs invade the niche space of neighboring wild-type GSCs and gradually push them out of the niche by upregulating E-cadherin expression. Furthermore, the bam/bgcn-mediated GSC competition requires E-cadherin and normal GSC division, but not the self-renewal-promoting BMP niche signal, while different E-cadherin levels can sufficiently stimulate GSC competition. Therefore, we propose that GSCs have a competitive relationship for niche occupancy, which may serve as a quality control mechanism to ensure that accidentally differentiated stem cells are rapidly removed from the niche and replaced by functional ones.
Stem cells can self-renew to maintain a stable population and generate differentiated cells to replenish lost cells in adult animal tissues, and their self-renewal and proliferation are tightly controlled by signals from their niche (Li and Xie, 2005,Ohlstein et al., 2004). Normally, stem cells reside in the same niche or tissue site and are capable of repopulating the empty niche space left by a lost stem cell (Xie and Spradling, 2000). However, it remains unclear how the stem cells in the same or nearby niche quickly respond to the loss of stem cells and carry out subsequent repopulation of vacant niches. In this study, we provide experimental evidence that the stem cells in the same niche have a competitive relationship, which may provide a quality control mechanism for removing differentiated stem cells from the niche.
Drosophila germline stem cells (GSCs) have become an attractive system for studying stem cell biology, including the niche structure and function and self-renewal mechanisms. In a structure known as the germarium, at the tip of the Drosophila ovary, two or three GSCs can be reliably recognized by their size (the largest germ cells), location (in direct contact with cap cells), and anteriorly anchored spherical spectrosome (SS), and they can be effectively studied at the molecular and cellular level (Lin, 2002,Xie et al., 2005) (Figures 1A and 1B). At the tip of the germarium, somatic cap cells and possibly escort stem cells (ESCs) form the GSC niche (Figure 1A), where GSCs are anchored to the cap cells through E-cadherin-mediated cell adhesion (Song et al., 2002,Xie and Spradling, 2000). Such anchorage is essential for keeping GSCs in their niche for long-term self-renewal since the GSCs defective in E-cadherin-mediated cell adhesion are lost rapidly from the niche (Song et al., 2002). Cystoblasts, the immediate progeny of GSCs, divide synchronously four times with incomplete cytokinesis to form interconnected 16-cell cysts sharing a branched fusome (de Cuevas et al., 1997) (Figure 1B). Spectrosomes and fusomes are germ-cell-specific organelles rich in membrane skeleton proteins such as adducin-like Hu li-tai shao (Hts) (Lin et al., 1994). In this study, we used this system to investigate how GSCs in the same niche interact with one another.
GSC self-renewal is primarily controlled by BMPs and piwi-mediated signals from the niche cells (Cox et al., 1998,Cox et al., 2000,Song et al., 2004,Xie and Spradling, 1998), and these signals maintain GSCs by repressing the expression of a differentiation-promoting gene, bag of marbles (bam) (Chen and McKearin, 2003a,Chen and McKearin, 2005,Song et al., 2004,Szakmary et al., 2005). On the other hand, the differentiation of cystoblasts requires bam and bgcn (benign gonial cell neoplasm), since mutations in either bam or bgcn result in the accumulation of spectrosome-containing undifferentiated single germ cells (Lavoie et al., 1999,McKearin and Spradling, 1990,Ohlstein et al., 2000) (Figures 1C and 1D). These differentiation-defective single germ cells resemble GSCs based on their gene expression profiles (Kai et al., 2005). In this study, we show that bam and bgcn also have important functions in GSCs in controlling their relative competitiveness.
In Drosophila imaginal discs, where cell competition is extensively studied, its Drosophila homolog of human proto-oncogene myc (dmyc) regulates the process (de la Cova et al., 2004,Moreno and Basler, 2004). Namely, dmyc mutant cells grow poorly and are outcompeted by their more vigorous wild-type neighboring cells (Johnston et al., 1999), while local dmyc overexpression causes cell competition by inducing the apoptosis of their neighboring wild-type cells (de la Cova et al., 2004). In the Drosophila ovary, dMyc protein is abundantly expressed in the nucleus of both somatic and germ cells throughout oogenesis (Maines et al., 2004). dmyc mutant follicle cells and germ cells exhibit defects in growth and endoreplication (Maines et al., 2004). Although dmyc is highly expressed in the nuclei of GSCs, its role in stem cells has not been established. In this study, we have developed an effective system for studying stem cell competition and then have shown that stem cells in the same niche have a competitive relationship, which is regulated by bam and bgcn, but not dmyc.
bam and bgcn Mutant GSCs Outcompete Wild-Type GSCs for Niche Occupancy
To investigate whether bgcn or bam mutant stem cells can have any competitive advantage over normal stem cells in occupying the niche, we chose bamΔ86, a deletion mutant of bam (McKearin and Spradling, 1990), and two bgcn mutants, bgcn20093 and bgcn20915, which bear a premature stop codon after residues 12 and 857, respectively (this study) to generate niches carrying a marked mutant bam or bgcn GSC and an unmarked wild-type GSC using the FLP-mediated FRT mitotic recombination (Xie and Spradling, 1998). Among 1-week-old mutant bamΔ86, bgcn20093 or bgcn20915 germaria labeled for Vasa (germ cells) and Hts (spectrosomes/fusomes), the bgcn20093 or bgcn20915 mutants contained only GSC-like single germ cells just like other previously characterized bgcn mutants (Ohlstein et al., 2000), and the bamΔ86 mutant germaria consistently had more GSC-like cells than those bgcn mutant germaria (Figures 1C and 1D), suggesting that the bam mutant GSC-like cells may proliferate faster than the bgcn mutants (Figures 1C and 1D).
Following the FLP/FRT-mediated mitotic recombination, the marked GSCs were identified by the absence of arm-lacZ expression, direct contact with cap cells, and an anteriorly anchored spectrosome, whereas the unmarked GSCs were identified by the presence of arm-lacZ expression, direct contact with cap cells, and an anteriorly anchored spectrosome (Xie and Spradling, 1998) (Figures 1E–1K). In this study, a "partial clone" is defined as a germarium carrying a mixture of marked and unmarked GSCs (Figures 1E and 1F), whereas a marked "full clone" is a germarium containing only two or three marked GSCs (Figure 1G). In the control, most of the marked GSCs detected 3 days after clone induction (ACI) were still maintained in the germaria 3 weeks ACI (Figures 1E and 1F); 25.2% of them were lost due to natural turnover, which was consistent with previous results (Song et al., 2002,Xie and Spradling, 1998) (Table 1). Since a lost GSC can be efficiently repopulated by the progeny of a neighboring GSC in the same niche (Xie and Spradling, 2000), a partial clone in the germarium carrying only two GSCs will become a full clone after losing the unmarked GSC. Since marked wild-type GSCs should behave like unmarked wild-type GSCs, and a wild-type control germarium usually carries 2.5 GSCs (n = 550), we would expect that the increased percentage of the germaria carrying a full clone is equal to about 40% of the percentage of the germaria losing a marked GSC. This agrees well with what we observed for wild-type control clones. From 3 days ACI to 3 weeks ACI, the percentage of the germaria carrying a partial clone decreased from 39.8% to 21.7% (18.1% net decrease), whereas the percentage of the germaria carrying a full clone increased from 1.8% to 9.4% (total 7.6% increase) (Table 1). Since natural GSC turnover is expected to be random, the lost marked wild-type GSCs should be roughly equal to the marked GSCs gained from replacement of the lost unmarked GSCs. Indeed, the percentage of marked GSCs versus total GSCs remained almost constant (without a net increase of the marked wild-type GSCs): 22.3% at 3 days ACI to 20.2% at 3 weeks ACI (Table 1). Together, this result shows that GSCs are an effective system to quantitatively study stem cell competition dynamics in the niche.
Table 1 |
Genotypes | Ages of Clones | Percentagea of the Germaria Carrying a Marked Full GSC Clone | Percentageb of the Germaria Carrying a Marked Partial GSC Clone | Percentagec of the Germaria Carrying a Marked GSC Clone | Percentaged of the GSCs Marked | Number of the Germaria Examined | ||
Control (FRT42D) | 3 days | 1.8% | 39.8% | 41.6% | 22.3% | 113 | ||
1 week | 7.6% | 33.8% | 41.4% | 23.6% | 225 | |||
2 weeks | 5.0% | 29.0% | 34.0% | 19.5% | 221 | |||
3 weeks | 9.4% | 21.7% | 31.1% | 20.2% | 212 | |||
bgcn20093 | 3 days | 6.6% | 38.3% | 44.9% | 25.1% | 183 | ||
1 week | 13.1% | 24.9% | 38.0% | 26.3% | 221 | |||
2 weeks | 27.6% | 20.8% | 48.4% | 37.6% | 221 | |||
3 weeks | 32.4% | 10.3% | 42.7% | 37.5% | 213 | |||
bgcn20915 | 3 days | 6.9% | 38.9% | 45.8% | 26.0% | 175 | ||
1 week | 12.4% | 37.6% | 50.0% | 33.6% | 226 | |||
2 weeks | 19.8% | 25.6% | 45.4% | 33.3% | 227 | |||
3 weeks | 27.1% | 13.8% | 40.9% | 34.9% | 225 | |||
bamΔ86 | 3 days | 2.2% | 41.9% | 44.1% | 20.8% | 143 | ||
1 week | 10.0% | 58.1% | 68.1% | 36.4% | 171 | |||
2 weeks | 32.4% | 53.7% | 86.1% | 61.6% | 205 | |||
3 weeks | 58.5% | 26.8% | 85.3% | 72.3% | 231 | |||
bgcn20093 shgR69 | 3 days | 6.5% | 20.4% | 26.9% | 15.5% | 186 | ||
1 week | 2.3% | 12.3% | 14.6% | 9.4% | 130 | |||
2 weeks | 9.8% | 5.8% | 15.6% | 12.6% | 173 | |||
3 weeks | 11.1% | 4.3% | 15.5% | 13.7% | 207 | |||
bgcn20915 shg10469 | 3 days | 1.9% | 36.7% | 38.6% | 20.0% | 215 | ||
1 week | 12.1% | 35.9% | 48.0% | 31.1% | 231 | |||
2 weeks | 19.8% | 19.4% | 39.2% | 29.7% | 217 | |||
3 weeks | 16.1% | 16.1% | 32.2% | 24.5% | 218 | |||
Control (FRT19A nos-gal4) | 1 week | 2.9% | 13.3% | 16.3% | 8.4% | 173 | ||
2 weeks | 4.3% | 9.8% | 14.1% | 7.6% | 163 | |||
3 weeks | 4.1% | 7.1% | 11.2% | 7.4% | 169 | |||
FRT19A nos-gal4; UAS-shg | 1 week | 6.1% | 13.9% | 20.0% | 12.3% | 165 | ||
2 weeks | 10.4% | 10.4% | 20.8% | 15.2% | 182 | |||
3 weeks | 11.8% | 5.6% | 17.4% | 14.2% | 195 | |||
a The percentage of the germaria carrying a marked full GSC clone at a given time point equals the number of germaria in which all GSCs are marked/total germaria examined. b The percentage of germaria carrying a partial marked GSC clone at a given time point equals the number of germaria in which at least one GSC is not marked and also at least one GSC is marked /total germaria examined. c The percentage of germaria carrying a marked GSC clone at a given time point equals the number of germaria carrying a marked full or partial GSC clone /total germaria examined. d The percentage of the GSCs marked equals the number of marked GSCs /total GSCs examined. |
Interestingly, the percentage of germaria carrying one or more marked bgcn20093 and bgcn20915 GSCs exhibited only a 4.9% and 10.7% reduction 3 weeks ACI, respectively, which is in contrast to a 25.2% reduction of marked wild-type GSCs, indicating that marked bgcn mutant GSCs are lost at a slower rate than marked wild-types (Table 1). The observation that blocking differentiation by bgcn mutations can prolong GSC lifespan also suggests that natural GSC turnover might be due to random differentiation. Moreover, we observed a dramatic increase in the percentage of germaria carrying a marked bgcn20093 or bgcn20915 full clone: from 6.6% at 3 days ACI to 32.4% at 3 weeks ACI for bgcn20093, and from 6.9% at 3 days ACI to 27.1% at 3 weeks ACI for bgcn20915, indicating that bgcn mutant GSCs can somehow replace their neighboring wild-type stem cells and occupy their niches (Figures 1H and 1I; Table 1). Similarly, we also observed a net increase in marked bgcn mutant GSCs: from 25.1% (3 days ACI) to 37.5% (3 weeks ACI) for bgcn20093 mutant GSCs and from 26.0% (3 days ACI) to 34.9% (3 weeks ACI) for bgcn20915 mutant GSCs (Table 1), which is in contrast to no obvious net increase of total marked wild-type GSCs. These results provide direct evidence that bgcn mutant GSCs can outcompete normal GSCs for their niches.
Since bgcn and bam have been proposed to function in the same genetic pathway to control GSC differentiation (Lavoie et al., 1999,Ohlstein et al., 2000), we would expect that bam mutant GSCs behave in the same way as bgcn mutant GSCs in stem cell competition. Surprisingly, the percentage of the germaria carrying a partial or full clone increased beyond the normal range of clone induction rate, from 44.1% at 3 days ACI to 86.1% at 2 weeks ACI (Table 1; Figures 1J and 1K), representing a 3-fold net increase in total marked GSCs. The newly gained marked bam mutant GSCs must come from the mutant bam cystoblasts that occupied the niches, which were normally occupied by unmarked wild-type GSCs, indicating that bam mutant cystoblasts can successfully invade the niche occupied by wild-type GSCs and assume GSC identity. Interestingly, during the period from 2 weeks ACI to 3 weeks ACI, the percentage of the germaria carrying a partial marked GSC clone decreased, while the percentage of germaria carrying a full clone showed a dramatic increase, from 32.4% to 58.5%, indicating that bam mutant GSCs are able to outcompete wild-type GSCs for their niches like bgcn mutant GSCs (Figures 1J and 1K; Table 1). As a consequence, there was a dramatic net increase of the marked GSCs (from 61.6% at 14 days ACI to 72.3% at 21 days ACI) (Table 1). All these data indicate that bam mutant GSCs are much more superior to wild-type GSCs in niche competition. However, it remains unclear why mutant bgcn cystoblasts cannot invade the GSC niche as efficiently as the bam mutant cystoblasts.
bam and bgcn Mutant GSCs Outcompete Their Neighboring Wild-Type GSCs, but Not through Inducing Differentiation and Apoptosis
In the Drosophila wing imaginal disc, fast growing cells induced by higher dmyc expression can outcompete and eliminate slow growing neighbors by promoting their apoptosis (de la Cova et al., 2004). To investigate whether bgcn and bam mutant GSCs outcompete wild-type GSCs by the same mechanism, we performed the TUNEL assay to detect if there were apoptotic GSCs in the germaria carrying both marked bam or bgcn mutant and unmarked wild-type GSCs. Interestingly, in the germaria with both one wild-type GSC and one marked mutant bgcn20093 or bgcn20915 GSC (total 163 germaria examined), neither the wild-type (lacZ-positive) GSCs nor the marked bgcn (lacZ-negative) mutant GSCs were apoptotic (Figure 2A). The same is also true for those germaria harboring both wild-type and bam mutant GSCs (total 120 germaria examined) (Figure 2B). In addition, differentiating lacZ-positive wild-type cysts were seen within the germaria, intermingling with the bgcn and bam mutant cell mass. These observations indicate that it is unlikely that the loss of the wild-type GSCs neighboring the marked mutant bam or bgcn GSCs is due to cell death.
To test whether the loss of unmarked wild-type GSCs is due to differentiation, we investigated the expression of bam-GFP in the unmarked wild-type GSCs sharing their niches with a marked bam or bgcn mutant GSC. As a GSC starts to differentiate, it immediately upregulates expression of bam-GFP (Chen and McKearin, 2003b). After examining 48 germaria carrying an 8-day-old bgcn20093 or bgcn20915 mutant GSC clone, we failed to observe bam-GFP expression in any of the unmarked wild-type GSCs (Figure 2C). Likewise, we did not observe any bam expression in any unmarked wild-type GSCs in the 45 germaria carrying an 8-day-old marked bam mutant GSC clone (Figure 2D). We also noticed that the unmarked wild-type GSCs that had already moved out of their niches did not express bam-GFP, suggesting that the unmarked wild-type GSCs are pushed out of their niches before they differentiate (Figures 2E and 2F). Consistent with this idea, we observed a trend of gradual loss of the wild-type GSC sharing the niche with a marked mutant bam or bgcn GSC over time (Figures 2G–2G″′). Therefore, our results indicate that bam or bgcn mutant GSCs outcompete their wild-type neighboring GSCs simply by forcing them out.
E-Cadherin Is Required for bam/bgcn-Mediated GSC Competition
shotgun (shg) encodes E-cadherin, which is essential for anchoring GSCs in the niche (Song et al., 2002). To investigate whether E-cadherin participates in bgcn-mediated GSC competition, we generated marked bgcn and shg double mutant GSCs using two different shg alleles, shg10469 and shgR69, which represent a hypomorphic allele and a null allele, respectively. The observed frequency of the germaria carrying a bgcn20915 shg10469 mutant full GSC clone was similar to that of the germaria carrying a bgcn20915 mutant full GSC clone, indicating that the weak shg10469 mutation only had a slight effect on bgcn-mediated GSC competition (Figures 3A and 3B; Table 1). In contrast, the frequency of the germaria carrying a bgcn20093 shgR69 mutant full GSC clone was significantly lower than that of the germaria carrying a bgcn20093 mutant full GSC clone, but was comparable to that of the germaria carrying a wild-type full GSC clone, indicating that the null shg mutation almost completely abolishes the competitive advantage of the bgcn mutant GSCs over the wild-type ones (Figures 3C and 3D; Table 1). These results demonstrate that E-cadherin is involved in the bgcn-mediated GSC competition. As reported previously, over 95% of the marked shgR69 mutant GSCs detected at 1 week ACI are lost at 3 weeks ACI (Song et al., 2002). It is worth noting that over 50% of the marked bgcn20093 shgR69 double mutant GSCs detected at 3 days ACI still remained in the niche at 3 weeks ACI, indicating that preventing shgR69 mutant GSCs from differentiation stabilizes their interactions with cap cells. Due to their location on different chromosomes, we could not investigate whether E-cadherin also takes part in bam-mediated GSC competition.
The bam/bgcn Pathway Negatively Regulates E-Cadherin Accumulation in the GSC-Niche Junction
It is possible that bam or bgcn mutant GSCs express higher levels of E-cadherin in the stem cell-niche junction and, thus, have a higher affinity for cap cells (niche cells) and a more competitive advantage for niche occupancy. We used the three-dimensional reconstruction of confocal sections (see Experimental Procedures ) to quantify E-cadherin in the stem cell-niche junction and the contact area with cap cells in the germaria carrying a wild-type GSC and a marked bam or bgcn mutant GSC. In the control germaria, the marked and unmarked wild-type GSCs in the same niche had similar contact areas in the stem cell-niche junction (38.2 ± 9.9 μm2 for the unmarked GSC and 37.4 ± 9.0 μm2 for the marked one; p = 0.70; n = 19), and also had similar amounts of E-cadherin accumulation in the junction with cap cells (the ratio of the unmarked GSC to the marked one = 1.09; p = 0.38; n = 19) (Figures 3E–3E″′). In contrast, the marked bamΔ86 mutant GSC had a significantly larger contact area with cap cells than the unmarked wild-type (35.1 ± 18.5 μm2 for the bam mutant GSC and 23.1 ± 12.5 μm2 for the wild-type one; p = 0.001; n = 20) and also had significantly more E-cadherin accumulation in the stem cell-niche junction than the unmarked wild-type in the same niche (the ratio of the bam mutant GSC to the wild-type = 2.31; p = 0.002; n = 20) (Figures 3F–3F″′). Similarly, the marked bgcn20093 mutant GSC had a significantly larger contact area with cap cells than the unmarked wild-type (44.2 ± 12.9 μm2 for the bgcn mutant GSC and 32.3 ± 11.6 μm2 for the wild-type; p = 0.0009; n = 15) and also had significantly more E-cadherin accumulation in the stem cell-niche junction than the unmarked wild-type in the same niche (the ratio of the bgcn mutant GSC to the wild-type = 1.73; p = 0.01; n = 15) (Figures 3G–3G″′). The observation that the bam and bgcn mutant GSCs have larger contact areas with cap cells than their wild-type counterparts in the same niches further supports the notion that the wild-type GSCs are gradually dislodged from the niche as a result of the invasion of the mutant GSCs. Therefore, our results strongly suggest that the increase of E-cadherin in the junction between mutant GSCs and cap cells is likely one of the primary determining factors for their stronger competitiveness.
The aforementioned findings also raise an interesting possibility that bam/bgcn might negatively regulate E-cadherin accumulation in the GSC. To test the possibility, we performed three-dimensional reconstruction to determine E-cadherin expression in the stem cell-niche junction 9 hr after bam overexpression using the hs-bam transgene, when the GSCs still remained in the niches and contained an anteriorly anchored spectrosome. Since the germaria carrying three stem cells could have a larger contact area and possibly more E-cadherin between the stem cells and cap cells (the niche) than the ones containing two stem cells, we focused our analyses only on the germaria carrying two stem cells. In the control experiments, the germaria from the control (yw) females (not carrying hs-bam) with heat shock treatments and the ones without heat shock treatments had similar E-cadherin accumulation in the stem cell-niche junction (the ratio = 1.00; p = 0.49; n = 14). In contrast, in the germaria of females carrying hs-bam, there was significantly less E-cadherin accumulation in the stem cell-niche junction after heat shock treatments, compared with those without heatshock treatments (the ratio = 0.68; p = 0.001; n = 15) (Figures 3H–3I′). This result demonstrates that bam upregulation in the GSC can sufficiently downregulate E-cadherin expression, which sheds light on why differentiated stem cells are detached from the niche. In conjunction with the fact that E-cadherin expression is increased in bam and bgcn mutant GSCs, this result leads us to conclude that bam/bgcn normally negatively regulate E-cadherin accumulation in the stem cell-niche junction.
Different Expression Levels of E-Cadherin Can Induce GSC Competition
Our earlier results also imply that the mutant GSCs defective in adhesion would have reduced their contact area with cap cells and, thus, are gradually competed out by their wild-type neighbors. To directly test this, we quantified the contact areas of the marked mutant shg GSC and the unmarked wild-type GSC in the mosaic germaria, which only host a shg mutant GSC marked by loss of arm-lacZ expression and an unmarked wild-type one with the expression of arm-lacZ. As shown in our previous study, most marked shg mutant GSCs are lost 2 weeks after clone induction (Song et al., 2002). Thus, we only examined the 1-week-old germaria carrying a mutant shg GSC and a wild-type GSC. As predicted, the unmarked wild-type GSCs indeed had a larger contact area with cap cells (52.2 ± 12.9 μm2) than their companion mutant shg GSCs (26.1 ± 7.7 μm2) in the same niche (n = 11; p = 0.0004; Figures 4A and 4B), indicating that the mutant shg GSCs are indeed gradually competed out by their neighboring wild-type GSCs.
We also further tested whether different E-cadherin expression levels in the GSCs in the same niche are sufficient to determine their relative competitiveness for niche occupancy. To generate a marked GSC that expresses different levels of E-cadherin from its neighboring GSCs, we utilized a combination of the FLP-mediated FRT recombination and the binary UAS-Gal4 expression system. In these experiments, Drosophila females carry a nanos (nos)-gal4VP16 located distal to FRT19A on one X chromosome and the ubi-GFP (a ubiquitin promoter-driven GFP) on the other X chromosome distal to FRT19A (Figure 4C). The nos-gal4VP16 was used to drive a UASp-E-cad-FLAG (a C-terminal FLAG-tagged E-cadherin controlled by a UASp promoter) to overexpress E-cadherin specifically in germ cells (Van Doren et al., 1998); (Pan et al., 2007), while ubi-GFP is ubiquitously expressed in all the cells of the germarium. After clone induction, the marked GFP-negative GSCs would carry two copies of nos-gal4VP16, while the GFP-positive GSCs carry only one copy of nos-gal4VP16. In order to test if the GSCs carrying two copies of nos-gal4 can indeed express more E-cadherin than the ones carrying only one copy of nos-gal4, we used the 3D reconstruction to measure expression levels of E-cadherin in the GFP− marked GSCs and their neighboring GFP+ unmarked GSCs. Indeed, the GFP-negative marked GSCs carrying two copies of nos-gal4 had significantly higher levels of E-cadherin than the GFP-positive unmarked GSCs carrying only one copy of nos-gal4 (the ratio of the former to the latter: 2.15; p = 0.0001; n = 13) (Figure 4D). Consequently, the GSCs expressing more E-cadherin (54.8 ± 17.8 μm2) had larger contact areas with cap cells than the GSCs expressing less E-cadherin (37.6 ± 9.8 μm2) (p = 0.001; n = 13; Figure 4E).
We then determined if the E-cadherin-overexpressing GSCs can expel their neighboring stem cells out of their niche. In this set of experiments, the initial clone induction rates at 1 week ACI for the control and E-cadherin overexpression were 16.3% and 20.0%, respectively, both of which were lower than earlier experiments. At 3 weeks ACI, the percentage of the germaria carrying a marked full clone in the control was 4.1%, which was much lower than that of the germaria carrying a partial clone (7.1%) (Table 1). In contrast, the germaria carrying a GFP-negative marked full clone carrying two copies of nos-gal4VP16 continued to increase from 1 week to 3 weeks ACI, and they became more prevalent than the germaria carrying a partial clone 3 weeks ACI (11.8% of the germaria carrying a full clone versus 5.6% of the germaria carrying a partial clone) (Figures 4F and 4G; Table 1). This result indicates that the GSCs expressing more E-cadherin are consistently more competitive than their neighbors expressing less E-cadherin. Together, our loss-of-function and gain-of-function experiments demonstrate that different levels of E-cadherin expression in GSCs within the same niche can stimulate stem cell competition.
Slow Proliferation of GSCs Compromises Their Competitiveness
As reported above, bam GSCs are more competitive than bgcn mutant GSCs, and bam mutant tumors are larger than bgcn mutant tumors, suggesting that the stronger competitiveness of bam mutant stem cells may result from their faster proliferation rate. We, therefore, used BrdU labeling to determine if the bam mutant GSCs indeed divide faster than bgcn mutant GSCs. In the 320 germaria carrying a lacZ-negative marked bam mutant GSC and a lacZ-positive unmarked wild-type GSC, there were 23 of the lacZ-negative bam mutant GSCs that were BrdU positive, while only 11 of the lacZ-positive wild-type GSCs were labeled by BrdU (the χ2 test: p = 0.04), indicating that bam mutant GSCs divide significantly faster than wild-type neighbors. In contrast, in the 258 germaria carrying a lacZ-negative marked bgcn mutant GSC and a lacZ-positive unmarked wild-type GSC, 11 of the lacZ-negative bgcn mutant GSCs and 15 of the lacZ-positive wild-type GSCs were positive for BrdU (the χ2 test: p = 0.433), indicating that bgcn mutant GSCs and wild-type neighbors divide at similar rates. These results suggest that bam mutant GSCs divide faster than bgcn mutant GSCs.
Based on the finding that bam mutant GSCs divide faster and are more competitive than bgcn mutant GSCs, we hypothesized that the rate of cell proliferation contributes to stem cell competitiveness. To test this hypothesis, we used the same strategy described earlier to generate marked GSCs mutant for both bam and dE2F1. dE2F1 is known to be important for controlling cell-cycle progression (Korenjak and Brehm, 2005), and two moderate dE2F1 mutants, dE2F17172 and dE2F1rM729, were used to disrupt dE2F1 function (Asano et al., 1996). In comparison with the control, the marked GSCs mutant for dE2F17172 and dE2F1rM729 were maintained for 3 weeks just like or close to the wild-type GSCs, and the marked mutant dE2F1 GSC clones detected at 1 week ACI could be frequently observed at 3 weeks ACI, indicating that these two dE2F1 mutations do not dramatically affect stem cell maintenance (Table 2; Figures 5A and 5B). The relative division rate for a marked GSC is determined by the number of cysts generated by a marked mutant GSC divided by the number of cysts generated by a marked wild-type GSC (Xi and Xie, 2005), and the marked mutant dE2F17172 and dE2F1rM729 GSCs had relative division rates of 0.45 (17 mutant GSCs examined) and 0.47 (16 mutant GSCs examined), respectively. These results indicate that different division rates are not sufficient for inducing stem cell loss, and that the two dE2F1 mutants are suitable for studying the effect of proliferation on stem cell competition. Interestingly, the marked GSC mutant for both bam and dE2F1 became much less competitive than the marked GSCs only mutant for bam. For example, at 3 weeks ACI, only 22.5% and 23.5% of the germaria carried bamΔ86 dE2F17172 and bamΔ86 dE2F1rM729 full clones in comparison with 58.5% of the germaria carrying marked bamΔ86 GSC full clones (Table 1,Table 2); the germaria carrying a partial bam dE2F1 mutant GSC clone were frequently observed (Figure 5C). These results indicate that different cell proliferation potentials contribute to, but do not sufficiently change, the relative competitiveness of stem cells for niche occupancy.
Table 2 |
Genotypes | Ages of Clones | Percentagea of the Germaria Carrying a Marked Full GSC Clone | Percentageb of the Germaria Carrying a Marked Partial GSC Clone | Percentagec of the Germaria Carrying a Marked GSC Clone | Number of the Germaria Examined | ||
Control (FRT82B) | 1 week | 1.6% | 31.3% | 33.0% | 182 | ||
2 weeks | 3.2% | 23.9% | 27.1% | 218 | |||
3 weeks | 4.3% | 22.2% | 26.5% | 185 | |||
dE2F17172 | 1 week | 4.6% | 38.3% | 32.2% | 174 | ||
2 weeks | 6.0% | 27.6% | 27.7% | 184 | |||
3 weeks | 10.0% | 21.7% | 24.2% | 190 | |||
dE2F17172 bamΔ86 | 1 week | 11.4% | 38.9% | 50.3% | 167 | ||
2 weeks | 23.2% | 31.9% | 55.1% | 185 | |||
3 weeks | 30.6% | 31.8% | 62.4% | 173 | |||
dE2F1rM729 | 1 week | 4.6% | 27.6% | 33.3% | 171 | ||
2 weeks | 4.8% | 20.2% | 25.0% | 168 | |||
3 weeks | 5.5% | 10.9% | 16.4% | 183 | |||
dE2F1rM729 bamΔ86 | 1 week | 9.1% | 46.3% | 55.4% | 175 | ||
2 weeks | 19.7% | 41.0% | 60.7% | 173 | |||
3 weeks | 28.7% | 38.9% | 67.7% | 167 | |||
bamΔ86Punt10460 | 3 days | 0.9% | 50.2% | 51.1% | 209 | ||
1 week | 10.5% | 65.0% | 75.5% | 161 | |||
2 weeks | 32.2% | 50.7% | 83.9% | 217 | |||
3 weeks | 60.2% | 28.0% | 88.2% | 211 | |||
bamΔ86punt135 | 3 days | 0.6% | 37.6% | 38.2% | 157 | ||
1 week | 6.3% | 58.0% | 64.3% | 207 | |||
2 weeks | 24.2% | 38.9% | 63.1% | 198 | |||
3 weeks | 54.6% | 28.2% | 82.8% | 227 | |||
a The percentage of the germaria carrying a marked full GSC clone at a given time point equals the number of germaria in which all GSCs are marked/total germaria examined. b The percentage of germaria carrying a partial marked GSC clone at a given time point equals the number of germaria in which at least one GSC is not marked and also at least one GSC is marked /total germaria examined. c The percentage of germaria carrying a marked GSC clone at a given time point equals the number of germaria carrying a marked full or partial GSC clone /total germaria examined. |
The GSC Competition Does Not Require BMP Signaling and dMyc Function
Since bam is proposed to negatively regulate BMP signaling (Casanueva and Ferguson, 2004), one explanation for the bam/bgcn-mediated GSC competition is that BMP signaling activities may be upregulated in the bam or bgcn mutant GSCs. The Dad-lacZ line has been extensively used to monitor BMP signaling activities in different tissue types, including the ovary (Casanueva and Ferguson, 2004,Kai and Spradling, 2003,Song et al., 2004). Interestingly, the marked bgcn mutant GSCs and their neighboring unmarked wild-type GSCs expressed Dad-lacZ at similar levels, indicating that BMP signaling activity does not change in bgcn mutant GSCs (Figures 5D and 5E). To directly test whether blocking BMP signaling could compromise bam-mediated stem cell competition, we used weak (punt10460) and strong (punt135) mutations of punt, which encodes the type II receptor essential for BMP signaling (Letsou et al., 1995,Ruberte et al., 1995), to block BMP signaling in bam mutant GSCs. The marked double punt10460 bamΔ86 or punt135 bamΔ86 GSCs still retained a similar ability to those marked bam mutant GSCs to outcompete wild-type GSCs in the same niches based on the percentages of germaria carrying a marked GSC full clone 3 weeks ACI, indicating that BMP signaling is not required for bam-mediated GSC competition (Figures 5F–5I; Table 1,Table 2). Corroborating the Dad-lacZ expression result, these results demonstrate that BMP signaling is not involved in the bam/bgcn-mediated GSC competition.
Since dmyc is capable of inducing cell competition in the Drosophila wing imaginal disc (de la Cova et al., 2004,Moreno and Basler, 2004), we sought to determine if dmyc is also involved in GSC competition by generating the marked GSCs homozygous for strong dmyc mutations, dm2 and dm4 (Maines et al., 2004,Pierce et al., 2004). Surprisingly, 69.7% and 73.5% of the marked dm2 and dm4 mutant GSCs detected at 1 week ACI were maintained at 3 weeks ACI, respectively, indicating that dmyc mutant GSCs are as stable as the marked controls (Table S1 and Figures S1 A–S1D). Furthermore, the marked dm2 and dm4 mutant GSCs had normal division rates, which are 1.0 (n = 16) and 0.91 (n = 39), respectively. To further investigate if overexpressing dmyc in the marked GSCs can strengthen their competitiveness, we used the same strategy for overexpressing E-cadherin to overexpress dmyc in marked GSCs. Interestingly, the percentages of the germaria carrying a GFP-negative marked GSC full clone, which carried two copies of nos-gal4 and should express more dmyc, decreased over time, indicating that dmyc overexpression does not make GSCs more competitive. Furthermore, the germaria carrying a marked GSC clone overexpressing dmyc appeared to be lost slightly faster than the controls (Figures S1 E–S1H). Together, our results show that dmyc is not essential for GSC competition.
In this study, we have shown that the differentiation-defective bam or bgcn mutant GSCs can drive wild-type stem cells away from their niche in an E-cadherin-dependent manner in the Drosophila ovary (Figure 5J). Our genetic and cell biological analyses indicate that different levels of E-cadherin expression in GSCs determine their competency in occupying the niche and that the bam/bgcn pathway controls E-cadherin protein expression levels in the GSC. Furthermore, we demonstrate that cell proliferation, but not BMP signaling or dMyc, modulates bam/bgcn-mediated GSC competition. This study also offers new insight into how a differentiated GSC is forced out of its niche by its neighboring stem cells. Its departure from the niche is probably caused by the upregulation of bam and consequent downregulation of E-cadherin. Such competition may serve as a quality control mechanism to ensure that the niche is always occupied by functional stem cells. Finally, the knowledge gained from studying stem cell competition may make it possible to deliver stem cells to diseased tissues by replacing nonfunctional stem cells in the future.
bam/bgcn Controls GSC Competition for Niche Occupancy by a Novel Mechanism
bam, encoding a novel protein with no previously known functional domain, is primarily expressed in a fraction of cystoblasts and proliferating cysts (McKearin and Ohlstein, 1995,McKearin and Spradling, 1990), while bgcn, encoding a putative RNA binding protein, is expressed in GSCs, cystoblasts, and proliferating cysts (Ohlstein et al., 2000). Mutations in bam and bgcn lead to accumulation of cystoblast-like or GSC-like single germ cells, further supporting the view that their functions are restricted to cystoblasts and proliferating cysts. In this study, however, we have shown that both bam and bgcn are required in GSCs to control their competitiveness in niche occupancy. This study also suggests that natural GSC turnover might be caused by the fluctuation of bam/bgcn function in GSCs. The competition mechanism we have discovered in this study could account for stem cell quality control and efficient replacement of lost GSCs due to their upregulated bam expression. Although bam is transcriptionally repressed by BMP signaling, low levels of bam transcription in the GSC can still be detected using the bam-GFP transgenic line (Figure S2 ). It is, therefore, possible that low levels of bam transcription detected in GSCs may provide a function for controlling GSC competitiveness.
Although mutations in bam and bgcn generate similar germ cell tumor phenotypes, there are two obvious differences in their mutant phenotypes. One difference is that bam mutant ovaries have more single germ cells than bgcn mutant ovaries. Our results show that bam mutant GSCs are more mitotically active than bgcn mutants, suggesting that bam has a bgcn-independent function in controlling GSC and/or cystoblast proliferation rates. The second difference is that mutant bam GSCs are more competitive than mutant bgcn GSCs in niche occupancy. This could be due to their difference in mitotic activities since we have shown in this study that the competitiveness of GSCs is modulated by mitotic activity. Taken together, we conclude that bam can function in bgcn-dependent and bgcn-independent manners to control the competitiveness of GSCs.
In the Drosophila imaginal disc, dmyc mediates cell competition by inducing apoptosis in disadvantaged cells (expressing less dmyc). This competitive behavior correlates with, and can be corrected by, the activation of the BMP/Dpp survival signaling pathway (Moreno and Basler, 2004). As shown in this study, however, dmyc and BMP signaling are dispensable for GSC competition, suggesting that GSCs use a distinct mechanism to control their competition. Indeed, we have shown that bam or bgcn mutant stem cells do not promote apoptosis or differentiation of their wild-type counterparts in the same niche. Instead, bam/bgcn mutant GSCs push their wild-type counterparts out of the niche through their adhesive advantage, which is supported by our observation that the mutant GSCs gradually increase E-cadherin accumulation at the GSC/cap cell junction. In addition, unlike in the imaginal disc, slowly dividing E2F1 mutant GSCs do not exhibit any obvious competitive disadvantages over wild-type neighbors. However, slow GSC division does compromise bam/bgcn-mediated GSC competition, since we observed that mutant bam dE2F1 GSCs are less competitive than bam mutant GSCs. The proliferation of the advantaged GSC may help produce a physical force to push the disadvantaged GSC out of its niche and occupy the space of the doomed GSC. Therefore, our study has revealed a novel function of bam/bgcn in stem cell competition and a novel mechanism for cell competition.
The bam/bgcn Pathway Controls GSC Competition by Regulating E-Cadherin Accumulation in the Stem Cell-Niche Junction
Our previous study showed that the mutant GSCs lacking E-cadherin are lost rapidly from their niche, but the underlying mechanism is not determined (Song et al., 2002). In this study, we provide an important insight into the mechanism by showing that the GSCs lacking E-cadherin lose their competition for the niche to their neighboring wild-type GSCs. This observation suggests that different levels of E-cadherin can induce competition among the GSCs in the same niche. Indeed, we have further shown that the GSCs expressing more E-cadherin become more competitive than the neighboring GSCs expressing less E-cadherin. Therefore, this study has demonstrated that different levels of E-cadherin in GSCs can sufficiently stimulate GSC competition for niche occupancy.
This study has also offered new mechanistic insights into why bam/bgcn mutant GSCs are more competitive than their neighboring wild-type GSCs. First, we show that bam and bgcn mutant GSCs accumulate more E-cadherin in the stem cell-niche junction than their neighboring wild-type counterparts. Second, bam overexpression is sufficient to downregulate E-cadherin accumulation in the junction. Together, these observations demonstrate that the bam/bgcn pathway is necessary and sufficient for controlling E-cadherin accumulation in the stem cell-niche junction. This bam/bgcn-mediated E-cadherin regulation may represent a quality control mechanism to ensure that a differentiated GSC triggered by a spontaneous mutation or abnormal upregulation of bam can be efficiently removed from the niche and then be replaced with a functional GSC generated by its neighboring GSC. Consistent with the notion that E-cadherin is involved in bam/bgcn-mediated cell competition, we showed that the removal of E-cadherin can abolish the competitive advantage of GSCs gained from bgcn mutations. However, it remains unclear why bam/bgcn mutant GSCs contain more E-cadherin in the stem cell-niche junction than their neighboring wild-type GSCs. Since bam/bgcn have been proposed to regulate translation (Ohlstein et al., 2000), it is possible that bam/bgcn normally control E-cadherin expression in GSCs by repressing its translation. Elucidating biochemical functions of Bam and Bgcn proteins will be essential for understanding how the bam/bgcn pathway controls GSC competitiveness.
Experimental Procedures
Generation of Marked GSC Clones
To determine the roles of bgcn and bam in GSC competition, we used the FLP-mediated mitotic recombination technique to generate and analyze mutant GSC clones of the following genotypes: (1) hs-FLP; FRT42D/FRT42D arm-lacZ; (2) hs-FLP; FRT42D bgcn20093/FRT42D arm-lacZ; (3) hs-FLP; FRT42D bgcn20915/FRT42D arm-lacZ; (4) hs-FLP;FRT82B bamΔ86/FRT82B arm-lacZ. To determine the potential role of E-cadherin or BMP signaling in regulating the bgcn/bam-mediated GSC competition, we performed analysis on double mutant GSC clones of the following genotypes: (1) hs-FLP; FRT42D bgcn20093 shgR69/FRT42D arm-lacZ; (2) hs-FLP; FRT42D bgcn20915 shg10469/FRT42D arm-lacZ; (3) hs-FLP; FRT82B bamΔ86 punt135/FRT82B arm-lacZ; (4) hs-FLP; FRT82B bamΔ86 punt10460/FRT82B arm-lacZ.
To determine the role of GSC division in regulating the bgcn/bam-mediated GSC competition, we performed analysis on dE2F1 single or dE2F1 bam double mutant GSC clones of the following genotypes: (1) hs-FLP;FRT82B/FRT82B arm-lacZ; (2) hs-FLP;FRT82B dE2F17172/FRT82B arm-lacZ; (3) hs-FLP;FRT82B dE2F1rM729/FRT82B arm-lacZ; (4) hs-FLP; FRT82B bamΔ86 dE2F17172/FRT82B arm-lacZ; (5) hs-FLP; FRT82B bamΔ86 dE2F1rM729/FRT82B arm-lacZ. To determine if dmyc is involved in regulating GSC competition, we analyzed marked dmyc mutant GSC clones of the following genotypes: (1) FRT19A/Ubi-GFP FRT19A; hs-FLP; (2) dmycdm2 FRT19A/Ubi-GFP FRT19A; hs-FLP; (3) dmycdm4 FRT19A/Ubi-GFP FRT19A; hs-FLP.
To assay whether mutations in bgcn or bam affect BMP signaling in GSCs, flies of the following genotypes were used: (1) hs-FLP;FRT42D bgcn20093/FRT42D ubi-GFP; Dad-lacZ; (2) hs-FLP; FRT42D bgcn20915/FRT42D ubi-GFP; Dad-lacZ. bam-GFP, which is under the control of the endogenous bam promoter (Chen and McKearin, 2003b), was used in this study to monitor bam expression in both bam and bgcn mutant GSCs. To carry out this experiment, flies of the following genotypes were generated: (1) hs-FLP; FRT42D bgcn20093/FRT42D arm-lacZ;bam-GFP; (2) hs-FLP; FRT42D bgcn20915/FRT42D arm-lacZ;bam-GFP; (3) hs-FLP;bam-GFP;FRT82B bamΔ86/FRT82B arm-lacZ.
To determine if E-cadherin and dMyc overexpression can induce GSC competition, we used the following genotypes: (1) nos-gal4VP16 FRT19A/Ubi-GFP FRT19A;hs-FLP; (2) nos-gal4VP16 FRT19A/Ubi-GFP FRT19A;UAS-E-cadherin-Flag/hs-FLP; (3) nos-gal4VP16 FRT19A/Ubi-GFP FRT19A;UAS-dmyc/hs-FLP.
Adult females, 3 to 5 days old, were heat-shocked twice daily at 37°C for 1 hr with a 7 to 8 hr interval for 3 consecutive days. Unless otherwise specified, fly ovaries were removed at 3 days, 1 week, 2 weeks, and 3 weeks after the last heat shock, and were then fixed for immunostaining as previously described (Xie and Spradling, 1998). For BrdU labeling of 1-week-old marked bam and bgcn GSC clones, the ovaries from the females carrying appropriate genotypes for bam or bgcn were processed 1 week after heat shock treatments, and BrdU detection was performed as described previously (Zhu and Xie, 2003).
The following antisera were used: monoclonal mouse anti-Hts antibody 1B1 (1:3, DSHB); monoclonal mouse anti-Arm N2 7A1 (1:3, DSHB); monoclonal rat anti-DE-Cadherin DCAD2 (1:3, DSHB); polyclonal rabbit anti-β-galactosidase antibody (1:300, Cappel); monoclonal mouse anti-β-galactosidase antibody (1:100, Promega); polyclonal rabbit anti-GFP antibody (1:200, Molecular Probes); rat anti-Vasa antibody (1:200, kindly provided by P. Lasko); Alexa 488- and Alexa 568-conjugated goat anti-mouse, anti-rabbit IgG, and anti-rat (1:300, Molecular Probes); and Cy5-conjugated goat anti-mouse IgG (1:200, Jackson ImmunoResearch). The immunostaining protocol and the TUNEL assay using an ApopTag kit from Chemion have been described previously (Kawase et al., 2004). All micrographs were taken using a Leica TCS SP2 confocal microscope.
Measuring Contact Areas and E-Cadherin between GSCs and Cap Cells
Using a Lecia SP2 confocal microscope, z stacks were taken along the z axis (0.5 μm each step) from those germaria that only bear one mutant and one control GSC or two GSCs in bam overexpression experiments. All images were acquired within the dynamic range of the detector at 12 bit depth. A contour plot for E-cadherin was generated with Imaris Bitplane (Saint Paul, MN). The contour was drawn along the boundary of a single GSC (or two GSCs in bam overexpressing germaria) and cap cells on each focal plane. After 3D reconstruction, a contour surface should represent the contact area between a single GSC (or two GSCs in bam overexpressing germaria) and cap cells. The intensity of E-cadherin staining on the contour surface was measured with Imaris Bitplane. All the p values were generated from the paired t test using Microsoft Excel unless otherwise specified.
We would like to thank B. Edgar, N. Dyson, P. Lasko, D. McKearin, T. Murphy, H. Oda, R. Padgett, D. Stein, and U. Tapass for reagents; Developmental Studies Hybridoma Bank (DSHB) for antibodies; D. Zhu for advice on statistical analysis; R. Krumlauf, R. Li, and N. Zhang for comments; the Xie laboratory members for stimulating discussions; the Stowers Institute facilities for services; and Dorothy Stanley for administrative assistance. This work is supported by a grant from the NIH (1R01 GM64428-01) and the Stowers Institute for Medical Research.
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Publication Information
Received: November 22, 2006
Revised: March 26, 2007
Accepted: October 30, 2007
Published: January 9, 2008


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Microsoft v. TomTom: Patent war, or no?
Last week, Microsoft promoted Horacio Gutierrez, formerly vice president of intellectual property, to corporate vice president. This week, Gutierrez polished his new business cards and sent them TomTom's way, with a patent infringement lawsuit.
As CNET News' Ina Fried reports, Microsoft on Wednesday launched a patent infringement lawsuit against TomTom, maker of GPS systems. TomTom, for its part, summarily rejects the claims and says it will "vigorously defend" itself. Lawsuits are filed all the time, but this one is of particular interest to the open-source community because it includes three claims of patent infringement related to Linux … Read more


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ABC Carrie Ann Inaba was drawn to tears when boyfriend Jesse Sloan popped the question on TV.Related Stories Cheap Original Beats By Dre Regis Philbin and Tony Danza give staffers a workout after managers at Reebok Sports Club try to shoo them from rooftop terrace Regis Philbin to host 'Rush Hour,' new daily talk show on Fox Sports 1? […] View
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Aquatic Nuisance - snakeheads
Giant Snakehead (Channa micropeltes)
Northern Snakehead (Channa argus)
Bullseye Snakehead (Channa marulius)
Blotched Snakehead (Channa maculata)
Where did they come from?
- Originated Southeast Asia (i.e. China, Korea, and Japan) and Russia.
Where can they be found in South Dakota?
- No species of snakehead is currently in South Dakota.
What do they look like?
Snakeheads have long, fully connected dorsal and anal fins.
Adult snakeheads have large visible teeth on both the upper and lower jaws.
Why are they a problem?
- The effects of snakehead introductions are widely unknown as the species has only recently been introduced to the United States.
- Since they are a largely piscivorous fish, it is believed they may directly compete with native predatory fishes such as walleye and pike.
How are they spread?
- It is believed that snakeheads were introduced to lakes and rivers by aquarists and fish markets after care for the animals became difficult and/or expensive.
Check out Aquatic Nuisance Species Prevention on ways to prevent the spread of Aquatic Nuisance Species
Snakehead links
USGS fact sheet on Giant Snakehead
USGS fact sheet on Northern Snakehead
USGS fact sheet on Bullseye Snakehead
USGS fact sheet on Blotched Snakehead
Pictures of Snakeheads
SD AIS Species
A.I.S. Fish
Asian Carp
Common Carp
Western Mosquitofish
European Rudd
A.I.S. Invertebrates
Zebra & Quagga Mussels
Rusty Crayfish
Asian Clam
New Zealand Mudsnail
Red-rimmed Melania
A.I.S. Plants
Brittle Naiad
Curlyleaf Pondweed
Flowering Rush
Eurasian Water Milfoil
Purple Loosestrife


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Judge cautions against some proposed reforms to NSA
President Obama is expected to announce a slew of possible reforms to the National Security Agency's surveillance programs on Friday. Within these proposed reforms are recommendations to limit spying on ally governments, stop the NSA's storage of telephone record data of US citizens, and increase controls on the secretive Foreign Intelligence Surveillance Court.
Unsurprisingly, judges of the FISC have taken issue with some of the proposed controls. Former presiding judge of the FISC and current director of the Administrative Office of the United States Court Judge John D. Bates penned a letter (PDF) to several lawmakers, which was … Read more


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Over-the-Top Hotel Pet Services
Some people really love their pets and will go to any lengths to keep them happy. The current pet-friendly hotel trend means that it's never been easier to spoil your dog rotten on the road. Here are Oyster.com's Top 5 most extravagant pet services.
Pet Room-Service Menus
Pet room-service menus are becoming standard at pet-friendly hotels these days, and many of them offer a lot more than your run-of-the-mill dog food. The inventiveness, and prices, of some of these gourmet treats caused us to raise an eyebrow -- or, in the case of the $98 caviar at Raffles L'Ermitage, two eyebrows. Here is a selection of the most elaborate offerings:
Loews Santa Monica Beach Hotel: Eggs with brown rice ($19)
Fairmont Miramar Hotel Santa Monica: 8-oz. filet of beef ($34). For dessert? Peanut butter petits fours, organic frozen yogurt and handmade truffles ($3-$9)
W New York Union Square: Pet hamburger ($15); 8-oz. sirloin ($18)
The Onyx: 8-oz. sirloin with kibble ($16)
Raffles L'ermitage Beverly Hills: Far and away the most lavish -- some might say ludicrous -- pet menu we've seen. Tuna tartar ($19), foie gras ($25), Osetra caviar with hard-poached eggs ($98)
Doggie Robes and Towels
At the sleep-themed Benjamin hotel in New York -- part of the pet-friendly Affinia chain -- dogs receive plush bathrobes to use during their stay as part of the Dream Dogs program. At the Peninsula Beverly Hills, pets receive monogrammed towels.Pet Psychics
As far as we can tell, very few people actually take advantage of this service, offered as part of the Affinia hotels Jet Set Pets Program, but it's there if you want it. Catherine Ferguson, Ph.D., "interspecies psychic," can help you deal with misbehaving pets, learn about your pet's past lives, find out what your pet thinks of your relationship and communicate with your deceased pets ($50 for a 20-minute phone consultation; $90 for a 60-minute in-person consultation).Gourmet Pet Cakes
Whether it's your pet's birthday or you just want to treat her to something special, some pet-friendly hotels can provide pets with a gourmet cake or treat. Hotel Marlowe -- our pick for one of the best pet-friendly hotels in Boston -- can order your pet peanut-butter-flavored cakes with cream-cheese frosting from the Polka Dog Bakery (round or heart-shaped, $22, flavors and shapes are subject to change). A guest requests one about every 6 weeks, according to the hotel.Spa Services
We've seen doggie massages, pedicures and shampoos offered through a number of top pet-friendly hotels. The Muse provides in-room pedicures for a guest and her dog as part of the Hers and Furs package, and the Epic Hotel in Miami offers a pet "pawdicure" and shampoo service, as well as 90-minute massages for 2 human guests, as part of its Epic Pet Getaway package.Check out more on Pet Travel.
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The Department of Environmental Studies is celebrating its 40th anniversary. See the schedule of events.
The world needs you now—to preserve biodiversity, work for environmental justice, reinvigorate science education, guide communities in planning for climate change, or promote sustainable practices in organizations, schools, and businesses.
Complete your degree in 16 to 20 months.
AUNE's Master of Science in Environmental Studies is a 42-credit program that takes five semesters to complete. The 30-credit Master of Science in Resource Management and Conservation can be completed in four semesters.
Choose a Professional Science Master's Option.
Help meet the demand for leaders in science- and math-related fields by earning a master's degree recognized as a Professional Science Master's. The Environmental Studies Master's of Science (ESMS) Program has been approved for recognition as a Professional Science Master's (PSM) by the Council of Graduate Schools. ESMS students can choose to follow either the PSM track of studies or the non-PSM track of studies.
Learn PSM track requirements and details here.
Learn from faculty who love to teach.
Our faculty are committed, first and foremost, to creating great learning opportunities. You'll find our faculty working side-by-side with students in the field and in the classroom, digging soil pits, mapping forest composition, tracking wildlife, and creating self-sustaining miniature biospheres.
Build your résumé and career network through internships and capstones.
Connect theory with practice by completing 6 credits of internship and a 3-credit capstone project in the field. Create and install a loon-nesting platform, research the spread of an invasive species, teach ecology at a residential learning center, meet with stakeholders on the siting of a new mall, or student teach AP science classes. We believe that internships and capstone projects are essential to your career development. You imagine the possibilities, and we'll do everything we can to support you.
Choose a rigorous program.
AUNE produces some of the brightest scientists, managers, educators, and activists in the field. Your journey and hard work will be as rewarding as the benefits of your degree.
Play the field.
Study wolves at Yellowstone, tropical ecology and conservation in Costa Rica, alpine flora in the White Mountains, and forest and tundra ecology on Mount Desert Island. Optional field study trips provide expanded opportunities for learning.


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2004 Toyota Camry Solara SLE V6
ProsBuild quality, smooth power delivery, nice amenities, good value Constransmission is not quick to respond, soft suspension
2004 Solara Sle V6 — Good looks and smooth power delivery. Suspension is a little soft, but comfortable on long trips. I imageine the resale value is not so good b/c of the deal I got on it, but it's a Toyota so the build quality is not in question and I imagine I'll keep it for some time. Great value for money in the used car world. Avg city mpg - 23 Highway - 30.
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2004 Toyota Camry Solara SLE V6
ProsGreat car to daily drive. Really quiet, and really comfortable for a car that starts just a little under $20,000. Can't compare daily driven comfort to other cars in this price range. ConsUnlike what the name suggests, it is not a sports car. It can become a good sports car, but this requires a lot of financial dedication and time. For those who want all of what this car has to offer, start by looking at what T.R.D. has to offer.
Good Daily Driver. — Great car to daily drive comfortably. If you are more concerned about gas mileage, get the I4 SE. If you want more power, get the SE V6 or the SLE V6 I have here. May not be everyone's favorite, but give it some time, and it will grow on you. I've added some aftermarket modifications to my own, and it's helped unlock some true latent ability hidden away in these great cars. This car is not a true sports car at first, and requires much work to make it a sport car. However, each improvement made to the car is a largely noticeable difference. It has had no major mechanical malfunctions, but small issues like fluid leaks and electrical sensor malfunctions has taken it's fair share on finances. |
2004 Toyota Camry Solara SLE Convertible
ProsFun to drive, great build quality, nice looking, quick ConsThrottle lag and the automanual slushbox takes hella time to shift in manual mode.
My Car: Batmobile. — I could have done better for the price, but I thought for my first car, getting a nice, solid Toyota would be good. It's pretty quick, but of course not a rally car or anything. It also drives a bit too smoothly, there's some throttle lag, and they added another unnecessary air filter thing to dull the engine noise, which I will take out soon (doesn't damage the car, it's just a noise dampener). The automanual/tiptronic or whatever you call it is basically a slushbox - takes forever to shift, which contributes to the throttle lag. One thing I hate is that it has virtually no aftermarket support - I can't really change it besides a basic intake mod... Oil change every 2-3k miles, not a hassle at all. Mileage is pretty cool, about 28 highway if I actually drive like a normal person. I've been running it on 87 octane though it does even better on premium (it's great with both). Oh, and it saved my ass in an accident... which could have been fatal. This car is really fun to drive, especially with the top down. |
2004 Toyota Camry Solara SLE V6
Proslooks, build quality, style, power Consoff the top of my head i have none so far!!
Great First Car! — Looks great, reliable, sorta sporty but with more relaxedness to it. I get a very surprised response when telling people that its 10 years old. Most think its brand new. Mine does only have 35,000 miles on it, got it for a great price and have never regretted it. Primary Use: Commuting to work |
2004 Toyota Camry Solara SE Sport V6
ProsThe sleek look and the JBL sound system ConsTerrible in the snow and lackluster MPG
Great Cruising Vehicle — This car is stylish and appealing on multiple levels. It's great for cruising but also has the extra power necessary to get in and out of lanes well. Because of it's large size for a coupe it can fit passengers comfortably in the back and has ample trunk space for storage. The sunroof also made it easy to enjoy on summer days driving down 95. However, in my use, gas became a problem for me and I never felt that I got enough out of a full tank. Also, when winter rolled around this car was a pain to deal with in the snow. Otherwise I would still rate this vehicle as one to own especially if gas isn't a problem or even if you have another vehicle and would just like this for your cruising pleasure. Primary Use: Commuting to work |
2004 Toyota Camry Solara SLE V6
ProsAcceleration and handling. ConsNo reasons
Classic Luxury Sports Coupe — Acceleration is fantastic as well as gas mileage with the V6 engine. This engine was also used in the Lexus ES330 that year. The interior is luxurious with supple leather buckets and genuine wood trim. Exterior styling is very current and aerodynamic. Handling is superb...no body lean or sloppiness. Primary Use: Family transportation |
2004 Toyota Camry Solara SLE
ProsGreat ConsNone
Best Car Ever!! — A Lexus in a Toyota car. Bought it new in 2004, it has been NO problem at all. Reg oil change every 3000mi, air filter,etc. I plan to get 200k mi or more out of it. No reason why we can't. We dont beat our cars!! We drive them with respect, so they last. 27mpg city and 31 highway! 4cyl 2.4 ltr.Great engine! 11-25-2009 Primary Use: Family transportation |
2004 Toyota Camry Solara SE Sport V6
ProsIts easy to handle and fun to drive. ConsTransmission if broken costs a fortune out of warrantee.
Cannot Beat It For The Class And The Money. — I love this car. Not too expensive to maintain, great handling, perfect for my needs, and its sexy. The looks that people give even though its a common car its still rare enough in New England for people to look. Nothing like a Mercedes but it rocks!!! Primary Use: Family transportation |
2004 Toyota Camry Solara
Prossee above Conssee above
Not Active
2004 Toyota Solara Sle — great fuel economy,quiet,smooth ride, decent acceleration,tight and no rattles etc., no repairs needed ,still feels new and stylish, quality finish, still gets looks,test drove lots and best bang 4 buck,love the heated seats in canada,only real negative is poor rear visibility shoulder checking |
2004 Toyota Camry Solara SLE V6
ProsLeather interior, sun roof, and 6 disk JBL cd player ConsLarge gas tank, lol
Displaying 1 - 10 of 16 2004 Toyota Camry Solara reviews.
Reviews From Other Years
2008 Toyota Camry Solara Reviews
Excellent Vehicle. By toyotaroadrunner
I have owned five (5) Toyota's throughout my life and everyone of them was a excellent vehicle. I have never had any major repairs done to any of my vehicles. The paint is excellent on these vehicles.... Read More
A Great Ride Into Retirement/re-living By didymop
We had a 2004 Solara Convertible SE. Decided we loved the cars safety features and comfort so we bought this 2008 SLE to take us into our retirement/re-living years. Even picked this car over our 2010... Read More
2007 Toyota Camry Solara Reviews
This Car Is Very Quiet And Has A Smooth Ride. By sssrrr
I drove a Honda Civic for 8 years. This car has been so much more fun to drive!! Very quiet and smooth ride! I felt extremely safe driving this car with side airbags. Lots of trunk space. High qua... Read More
2007 Toyota Solara Convertable By tliddle
This is my new ride. She's replacing my 1999 Chrysler Sebring (convertable). I had to have a drop top - and this one is in fine shape! I cannot WAIT to drive her tomorrow! Even if it is raining all w... Read More
2006 Toyota Camry Solara Reviews
Low Mileage Sporty Convertible By judywicker47
This Solara can serve a wide range of needs spanning sporty yet economical coupe to luxurious spacious cruiser. It has a comfortable ride, is fuel efficient, and has only 30000 miles under the hood. ... Read More
Great Mileage,power To Spare. Fun To Drive By tommcmanis
It looks stylish w rakish lines, like a traffic stop waiting to happen. Rear of the car looks funky. Toyota made up for it under the hood 3.3 vvti engine coupled to a five speed automatic,sadly four c... Read More
2005 Toyota Camry Solara Reviews
Love Driving This Car. By mrhoades12
Great car to drive. It is fun to drive. Great sound system. Adequate seating and storage which is unusable for convertible. Good gas mileage. Very reliable. Very little maintenance needed other ... Read More
Toyota Solara By jtl10
Vehicle was purchased in Miami, Florida, from a dealer with only one previous owner prior to me. Car has been garage kept, excellent paint, interior is gorgeous, and gas mileage is amazing! Handles fa... Read More
2003 Toyota Camry Solara Reviews
Impressive By Kevinfinni
Like most everything about this car. The comfort,style,performance,quality. I was impresses with this car the first time I drove it. I commute 150 miles one way and it performs incredible for a 10 yea... Read More
Looks Good , Runs Good By fiexcoinc
Car runs good, has good power and is very stable ride. Interior is leather and has a lot of room for a 2 door coupe. Car is 4 cylinder and is good on gas. Car runs and drives good and is very stable o... Read More
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