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Structure b represents diplococcus bacteria. Diplococci are pairs of cocci. Examples of gram-negative diplococci are Neisseria spp. and Moraxella catarrhalis. Examples of gram-positive diplococci are Streptococcus pneumoniae and Enterococcus spp. [10] [11] Presumably, diplococcus has been implicated in encephalitis lethargica. [12]
Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. [1] Their defining characteristic is that their cell envelope consists of a thin peptidoglycan cell wall sandwiched between an inner ( cytoplasmic ) membrane and an outer ...
Helicobacter pylori is a species of gram-negative bacteria in the Helicobacter genus. [23] About half the world's population is infected with H. pylori but only a few strains are pathogenic. H pylori is a helical bacterium having a predominantly helical shape, also often described as having a spiral or S shape.
Gram-negative and mycobacteria have an inner and outer bacteria membrane. As a phospholipid bilayer , the lipid portion of the bacterial outer membrane is impermeable to charged molecules. However, channels called porins are present in the outer membrane that allow for passive transport of many ions , sugars and amino acids across the outer ...
Bacterial morphological plasticity refers to changes in the shape and size that bacterial cells undergo when they encounter stressful environments. Although bacteria have evolved complex molecular strategies to maintain their shape, many are able to alter their shape as a survival strategy in response to protist predators, antibiotics, the immune response, and other threats.
Treponema pallidum is a helically shaped bacterium with high motility consisting of an outer membrane, peptidoglycan layer, inner membrane, protoplasmic cylinder, and periplasmic space. [9] It is often described as gram-negative, but its outer membrane lacks lipopolysaccharide, which is found in the outer membrane of other gram-negative ...
Helicobacter is a genus of gram-negative bacteria possessing a characteristic helical shape. They were initially considered to be members of the genus Campylobacter, but in 1989, Goodwin et al. published sufficient reasons to justify the new genus name Helicobacter. [2] The genus Helicobacter contains about 35 species. [3] [4] [5]
Campylobacter is a helical-shaped, non-spore-forming, Gram-negative, microaerophilic, nonfermenting motile bacterium with a single flagellum at one or both poles, [6] which are also oxidase-positive and grow optimally at 37 to 42 °C.