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In microbiology are called Gram positive bacteria those bacteria that are stained dark blue or violet by Gram stain : hence the name "Gram-positive", or "gram-positive." [1] This feature is closely linked to the structure of the cell envelope therefore reflects a natural type of bacterial organization. They are one of the major groups of bacteria , and when treated as a taxon also uses the name Posibacteria. [2] The remaining are Gram-negative bacteria. The cell envelope
of Gram-positive bacteria includes cytoplasmic membrane and cell wall composed by a thick layer of peptidoglycan , surrounding the above. The cell wall binds to the cytoplasmic membrane by lipoteichoic acid molecules . Peptidoglycan layer confers strong resistance to these bacteria and is responsible to retain the dye during the Gram stain. Unlike Gram-negative , Gram-positive do not have a second outer lipid membrane to the cell wall and this wall is much thicker. [3]
species include both mobile (via flagella) as stationary shaped bacillus ( Bacillus, Clostridium , Corynebacterium , Lactobacillus, Listeria ) or coconut ( Staphylococcus, Streptococcus ) with thick cell walls or without ( Mycoplasma ). Some species are photosynthetic , but most are heterotrophic . Many of these bacteria form endospores in unfavorable conditions. [4] Actually, not all bacteria are Gram-positive group (not stained by the application of this method), but are included here because of its molecular similarity with other Gram-positive bacteria. In
microbiology is Gram-negative bacteria called these bacteria do not stain dark blue or violet by Gram stain, and do a color faint pink, hence the name "Gram-negative" or also "Gram." [1] This feature is closely linked to the structure of the cell envelope therefore reflects a natural type of bacterial organization. They are one of the major groups of bacteria they are treated as taxon is also used Negibacteria name. [2] The remaining bacteria are Gram positive .
Gram-negative bacteria have two lipid membranes between which is located a thin cell wall peptidoglycan of , while Gram-positive bacteria have only one lipid membrane and the wall is much thicker peptiglicano. Being thin wall, does not retain the dye during the Gram stain. [3]
Many species of Gram-negative bacteria cause disease. The Gram-negative cocci cause gonorrhea (Neisseria gonorrhoeae ) meningitis (Neisseria meningitidis ) and respiratory symptoms (Moraxella catarrhalis ), among others. The Gram-negative bacilli include a large number of species. Some of them primarily cause respiratory disease (Haemophilus influenzae , Klebsiella pneumoniae, Legionella pneumophila , Pseudomonas aeruginosa ), urinary diseases ( Escherichia coli, Proteus mirabilis , Enterobacter cloacae, Serratia marcescens ) and gastrointestinal ( Helicobacter pylori, Salmonella enteritidis , Salmonella typhi ). Others are associated with nosocomial infections (Acinetobacter baumannii ).
of Gram-positive bacteria includes cytoplasmic membrane and cell wall composed by a thick layer of peptidoglycan , surrounding the above. The cell wall binds to the cytoplasmic membrane by lipoteichoic acid molecules . Peptidoglycan layer confers strong resistance to these bacteria and is responsible to retain the dye during the Gram stain. Unlike Gram-negative , Gram-positive do not have a second outer lipid membrane to the cell wall and this wall is much thicker. [3]
species include both mobile (via flagella) as stationary shaped bacillus ( Bacillus, Clostridium , Corynebacterium , Lactobacillus, Listeria ) or coconut ( Staphylococcus, Streptococcus ) with thick cell walls or without ( Mycoplasma ). Some species are photosynthetic , but most are heterotrophic . Many of these bacteria form endospores in unfavorable conditions. [4] Actually, not all bacteria are Gram-positive group (not stained by the application of this method), but are included here because of its molecular similarity with other Gram-positive bacteria. In
microbiology is Gram-negative bacteria called these bacteria do not stain dark blue or violet by Gram stain, and do a color faint pink, hence the name "Gram-negative" or also "Gram." [1] This feature is closely linked to the structure of the cell envelope therefore reflects a natural type of bacterial organization. They are one of the major groups of bacteria they are treated as taxon is also used Negibacteria name. [2] The remaining bacteria are Gram positive .
Gram-negative bacteria have two lipid membranes between which is located a thin cell wall peptidoglycan of , while Gram-positive bacteria have only one lipid membrane and the wall is much thicker peptiglicano. Being thin wall, does not retain the dye during the Gram stain. [3]
Many species of Gram-negative bacteria cause disease. The Gram-negative cocci cause gonorrhea (Neisseria gonorrhoeae ) meningitis (Neisseria meningitidis ) and respiratory symptoms (Moraxella catarrhalis ), among others. The Gram-negative bacilli include a large number of species. Some of them primarily cause respiratory disease (Haemophilus influenzae , Klebsiella pneumoniae, Legionella pneumophila , Pseudomonas aeruginosa ), urinary diseases ( Escherichia coli, Proteus mirabilis , Enterobacter cloacae, Serratia marcescens ) and gastrointestinal ( Helicobacter pylori, Salmonella enteritidis , Salmonella typhi ). Others are associated with nosocomial infections (Acinetobacter baumannii ).
Comparison of bacterial cell envelopes . Top: Gram-positive bacteria. 1 - cytoplasmic membrane, 2 - peptidoglycan , 3 - phospholipids, 4 - protein, 5 - lipoteichoic acid. Below: Gram-negative bacteria. 1 - cytoplasmic membrane (inner membrane), 2 - periplasmic space, 3-outer membrane, 4 - phospholipids, 5 - peptidoglycan , 6 - lipoprotein , 7 - protein, 8 - lipopolysaccharide, 9 - porins.
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