Cell membranes bacterium

Some prokaryotes are anaerobic heterotrophs. These include the denitrifiers, sulfate reducers, and fermenters, as well as the bacteria capable of reducing metals, such as Fe(lll) to Fe(II) and Mn(lV) to Mn(II). Because the oxidized metals are present as solids, e.g., FeOOH(s), Fe203(s), and Mn02(s), these bacteria must be in direct contact with the mineral surface and have a mechanism for transferring electrons across their cell membranes. One bacterium that appears to have such a mechanism is the facultative anaerobe Shewanella oneidensis, which produces a specific protein on its outer membrane only under anaerobic conditions when it is in direct contact with a suitable... 

Haines reported that ozone at 4 ppm retarded growth of Escherichia colit whereas 10 ppm prevented growth. Scott and Lesher found that approximately 2 x 10 molecules of ozone per bacterium killed 50% of the cells of E. coli and that the primary effect was on the cell membrane. 

Two other types of specialized transport mechanisms, pinocytosis and phagocytosis, may also account for the transmembrane movement of some macromolecules (2). In these complex processes, the cell engulfs a droplet of extracellular fluid or a particle of solid material such as a bacterium. The droplet or particle is completely surrounded by a portion of the cell membrane and the resulting vesicle becomes detached and moves into the cell cytoplasm. 

Structure of a Peptide Antibiotic from Bacillus brevis Extracts from the bacterium Bacillus brevis contain a peptide with antibiotic properties. This peptide forms complexes with metal ions and apparently disrupts ion transport across the cell membranes of other bacterial species, killing them. The structure of the peptide has been determined from the following observations. 

TSome microbial pathogens have lectins that mediate bacterial adhesion to host cells or toxin entry into cells. The bacterium believed responsible for most gastric ulcers, Helicobacter pylori, adheres to the inner surface of the stomach by interactions between bacterial membrane lectins and specific oligosaccharides of membrane glycoproteins of the gastric epithelial cells... 

Daptomycin (Cubicin) is unique in that this drug binds to the cell membrane of susceptible bacteria and depolarizes the cell. Loss of membrane polarity results in a general inhibition of cell function and subsequent death of the bacterium. This drug is used primarily to treat skin infections caused by certain staphylococcal, streptococcal, and enterococcal bacteria. Because of its unique mechanism of action, daptomycin may also be... 

Soaps and detergents have bactericidal properties. These non-native surfactants can work their way into the bacterium s cell membrane and disrupt the integrity of the cell membrane, causing the bacterium to die. Of course, fatty acids are also high-energy food sources, so soaps and detergents lose this bactericidal property at low concentrations. 

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