Gram-positive bacteria possess a thick cell wall containing many layers of peptidoglycan and teichoic acids. In contrast, gram-negative bacteria have a relatively thin cell wall consisting of a few layers of peptidoglycan surrounded by a second lipid membrane containing lipopolysaccharides and lipoproteins. Lipopolysaccharides, also called endotoxins, are composed of polysaccharides and lipid A that is responsible for much of the toxicity of gram-negative bacteria. Most bacteria have the gram-negative cell wall, and only the Firmicutes and Actinobacteria have the alternative gram-positive arrangement. These two groups were previously known as the low G+C and high G+C Gram-positive bacteria, respectively. These differences in structure can produce differences in antibiotic susceptibility; for instance, vancomycin can kill only gram-positive bacteria and is ineffective against gram-negative pathogens, such as Haemophilus influenzae or Pseudomonas aeruginosa. If the bacterial cell wall is entirely removed, it is called a protoplast, whereas if it is partially removed, it is called a spheroplast. β-Lactam antibiotics, such as penicillin, inhibit the formation of peptidoglycan cross-links in the bacterial cell wall. The enzyme lysozyme, found in human tears, also digests the cell wall of bacteria and is the body's main defense against eye infections.
Gram - positive bacteria possess a thick cell wall containing many layers of peptidoglycan and teichoic acids . In contrast , gram - negative bacteria have a relatively thin cell wall consisting of a few layers of peptidoglycan surrounded by a second lipid membrane containing lipopolysaccharides and lipoproteins . Lipopolysaccharides , also called endotoxins , are composed of polysaccharides and lipid A that is responsible for much of the toxicity of gram - negative bacteria . Most bacteria have the gram - negative cell wall , and only the Firmicutes and Actinobacteria have the alternative gram - positive arrangement . These two groups were previously known as the low G+C and high G+C Gram - positive bacteria , respectively . These differences in structure can produce differences in antibiotic susceptibility ; for instance , vancomycin can kill only gram - positive bacteria and is ineffective against gram - negative pathogens , such as Haemophilus influenzae or Pseudomonas aeruginosa . If the bacterial cell wall is entirely removed , it is called a protoplast , whereas if it is partially removed , it is called a spheroplast . β - Lactam antibiotics , such as penicillin , inhibit the formation of peptidoglycan cross - links in the bacterial cell wall . The enzyme lysozyme , found in human tears , also digests the cell wall of bacteria and is the body 's main defense against eye infections .
What can be endotoxins called?
What can be endotoxins called ?
Lipopolysaccharides
Lipopolysaccharides