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What is Vibrio cholerae was discovered (1883) by and explain in detail?
Ans. c (Robert Koch) (Ref. Ananthanarayan Microbiology, 7th/ pg.2)Robert Koch is known for -# Co-founder of bacteriology,# Koch's postulates of germ theory,# Isolator of anthrax# Isolator of tuberculosis and choleraVibrio# Vibrio cholerae, was discovered in 1883 by the German physician and bacteriologist Robert Koch.# Vibrio cholerae is short curved cylindrical rod (typically comma shaped).# Are gram-negative and non-acid fast.# They are asporogenous and noncapsulated.# It is actively motile with single sheathed polar flagellum showing darting type.# It ferments glucose, mannitol, maltose, mannose and sucrose. Indole is formed and nitrates are reduced.# These two properties give "cholera red" reaction.# It is transported in alkaline medium. The media used are:1. Venkatraman -Ramakrishna medium: 20 g crude sea salt + 59 peptone in 1L of distilled water + pH of 8.6-8.8.2. Carry-Blair medium: NaCl + sodium thioglycolate + CaCl2 + disodium phosphate at pH 8.4.3. Autoclaved seawater.# V. cholerae exotoxin ADP ribosylates Gsa, leading to cAMP & subsequent diarrhea.# Vibrios that have a high requirement of NaCl are known as halophilic vibrios. which include:- V. parahaemolyticus- V. alginolyticus- V. vulnificus- V. fluvitalisAlso Know:# Main discoveries of Antonie van Leeuwenhoek: 1) RBCs, 2) Infusoria, 3) Spermatozoa and 4) Bacteria.# Staphylococci were first observed and cultured by Pasteur and Koch, but the initial detailed studies on staphylococci were made by Ogston in 1881 and Rosenbach in 1884.# The name 'genus Staphylococcus' was given by Ogston when he obs grape-like clusters of bact in pus from abscesses.# Three years later, Rosenbach was able to isolate and grow these microorganisms in pure culture. He gave these bacteria the specific epithet Staphylococcus aureus because of the yellow-to-orange pigmented app. of their colonies.