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Xochitecatl [ʃot͡ʃiˈtekat͡ɬ] is a pre-Columbian archaeological site located in the Mexican State of Tlaxcala, 18 km southwest of Tlaxcala city. [1] The major architecture dates to the Middle Preclassic Period (1000–400 BC) but occupation continued, with one major interruption, until the Late Classic , when the site was abandoned.
Heat-stable enterotoxins (STs) are secretory peptides produced by some bacterial strains, such as enterotoxigenic Escherichia coli [2] which are in general toxic to animals. These peptides keep their 3D structure and remain active at temperatures as high as 100 °C.
An exoenzyme, or extracellular enzyme, is an enzyme that is secreted by a cell and functions outside that cell. Exoenzymes are produced by both prokaryotic and eukaryotic cells and have been shown to be a crucial component of many biological processes. Most often these enzymes are involved in the breakdown of larger macromolecules.
These toxins are produced by Vibrio species of bacteria and like to accumulate in marine life such as the pufferfish. These toxins are produced when Vibrio bacteria are stressed by changes in temperature and salinity of environment which leads towards production of toxins. The main hazard towards humans is during consumption of contaminated ...
The bacterial cell wall differs from that of all other organisms by the presence of peptidoglycan which is located immediately outside of the cell membrane. Peptidoglycan is made up of a polysaccharide backbone consisting of alternating N-Acetylmuramic acid (NAM) and N-acetylglucosamine (NAG) residues in equal amounts.
The general secretion (Sec) involves secretion of unfolded proteins that first remain inside the cells. In Gram-negative bacteria, the secreted protein is sent to either the inner membrane or the periplasm. But in Gram-positive bacteria, the protein can stay in the cell or is mostly transported out of the bacteria using other secretion systems.
Structure of a teichoic acid repeat unit from Micrococcaceae Structure of the lipoteichoic acid polymer. Teichoic acids (cf. Greek τεῖχος, teīkhos, "wall", to be specific a fortification wall, as opposed to τοῖχος, toīkhos, a regular wall) [1] are bacterial copolymers [2] of glycerol phosphate or ribitol phosphate and carbohydrates linked via phosphodiester bonds.
Biofilms may be structurally complex and may attach to solid surfaces, or exist at liquid-air interfaces. Bacterial biofilms are often made up of microcolonies (dome-shaped masses of bacteria and matrix) separated by channels through which water may flow easily. Microcolonies may join together above the substratum to form a continuous layer.