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The most bacteria were obtained from the upper 3cm of sediment in the sample, with concentrations decreasing exponentially past this point. [18] Here, Thiomargarita namibiensis is easily suspended in moving ocean currents due to the sheath around the cells, which makes it easy for the bacteria to passively float. [19]
Many bacteria secrete extracellular polymers outside of their cell walls called glycocalyx. These polymers are usually composed of polysaccharides and sometimes protein. Capsules are relatively impermeable structures that cannot be stained with dyes such as India ink. They are structures that help protect bacteria from phagocytosis and desiccation.
Spiral bacteria are another major bacterial cell morphology. [2] [30] [31] [32] Spiral bacteria can be sub-classified as spirilla, spirochetes, or vibrios based on the number of twists per cell, cell thickness, cell flexibility, and motility. [33] Bacteria are known to evolve specific traits to survive in their ideal environment. [34]
The endosteum (pl.: endostea) is a thin vascular membrane of connective tissue that lines the inner surface of the bony tissue that forms the medullary cavity of long bones. [ 1 ] [ 2 ] This endosteal surface is usually resorbed during long periods of malnutrition , resulting in less cortical thickness.
An endospore stain of the cell Bacillus subtilis showing endospores as green and the vegetative cell as red Phase-bright endospores of Paenibacillus alvei imaged with phase-contrast microscopy. An endospore is a dormant, tough, and non-reproductive structure produced by some bacteria in the phylum Bacillota.
The vegetative cells of clostridia are heat-labile and are killed by short heating at temperatures above 72–75 °C (162–167 °F). The thermal destruction of Clostridium spores requires higher temperatures (above 121.1 °C (250.0 °F), for example in an autoclave ) and longer cooking times (20 min, with a few exceptional cases of more than ...
The Gram stain, developed in 1884 by Hans Christian Gram, characterises bacteria based on the structural characteristics of their cell walls. [ 182 ] [ 80 ] The thick layers of peptidoglycan in the "Gram-positive" cell wall stain purple, while the thin "Gram-negative" cell wall appears pink. [ 182 ]
Endospore stain on Bacillus subtilis.The spore is stained green and the vegetative cell is stained a pinkish red color. Endospore staining is a technique used in bacteriology to identify the presence of endospores in a bacterial sample. [1]