Bacteria characteristics

Fatty acids in the 12-20 carbon chain-length range account for the majority of bacterial fatty acids. These are usually saturated or monounsaturated polyunsaturated fatty acids only occur in a few species, such as the gliding bacteria which accumulate large amounts of arachidonate (Fautz et al., 1979) or cyanobacteria which contain linoleate and linolenate. Reports of polyunsaturated fatty acids in bacteria should be treated with scepticism because of the ease with which bacteria can take up growth constituents which can include polyunsaturates. Besides the ubiquitous even-chain saturated and unsaturated fatty acids bacteria characteristically contain odd-chain and branched fatty acids as well as 3-hydroxy-and cyclopropane derivatives. These fatty acids are present in lipopolysaccharide, cell wall lipoprotein and lippteichoic acid as well as membrane glycerolipids (Table 3.209). 

Characteristics of developing resistance to Antibiotics by bacteria Characteristics of developing resistance to Biocides by bacteria... 

Biological Systems. Whereas Raman spectroscopy is an important tool of physical biochemistry, much of this elegant work is of scant interest to the industrial chemist. However, Raman spectroscopy has been used to locate cancerous cells in breast tissue (53) and find cataractous tissue in eye lenses (54), suggesting a role in industrial hygiene (qv). Similarly, the Raman spectra of bacteria are surprisingly characteristic (55) and practical apphcations are beginning to emerge. 

A study to isolate and examine the genetic characteristics of bacteria that metaboli2e chlorotoluenes, such as OCT, PCT, and 2,6-dichlorotoluene, has been reported (74). Two products were isolated from a study of the metaboHsm of PCT by Pseudomonasputida ... 

The circumstances under which water becomes contaminated are as varied as the ways water is taken internally. It is then conceivable that almost any virus could be transmitted through the water route. The increased use of water for recreational purposes increases the incidence of human contact with bodies of water and, consequently, with waterborne viruses and bacteria. The major waterborne viruses among pathogens, and the most likely candidates for water transmission, are the picornaviruses (from pico, meaning very small, and RNA, referring to the presence of nucleic acid). The characteristics of picornaviruses are shown in Table 1. Among the picornaviruses are the enteroviruses (polioviruses, coxsackieviruses. 

FIGURE 2.16 pH versus enzymatic activity. The activity of enzymes is very sensitive to pH. The pH optimum of an enzyme is one of its most important characteristics. Pepsin is a protein-digesting enzyme active in the gastric fluid. Trypsin is also a proteolytic enzyme, but it acts in the more alkaline milieu of the small intestine. Lysozyme digests the cell walls of bacteria it is found in tears. 

As shown in Figure 9.24, the outer membrane of Gram-negative bacteria is coated with a highly complex lipopolysaccharide, which consists of a lipid group (anchored in the outer membrane) joined to a polysaccharide made up of long chains with many different and characteristic repeating structures... 

Another important group of cytochromes, found in plants, bacteria and animals is cytochrome P-450, so-called because of the absorption at 450 nm characteristic of their complexes with CO. Their function is to activate... 

III building their characteristic cell walls, bacteria utilize... 

Bacterial activity often plays a major part in determining the corrosion of buried steel. This is particularly so in waterlogged clays and similar soils, where no atmospheric oxygen is present as such. If these soils contain sulphates, e.g. gypsum and the necessary traces of nutrients, corrosion can occur under anaerobic conditions in the presence of sulphate-reducing bacteria. One of the final products is iron sulphide, and the presence of this is characteristic of attack by sulphate-reducing bacteria, which are frequently present (see Section 2.6). 

The presence of active sulphate-reducing bacteria usually results in graphitic corrosion and this has led to a useful method of diagnosing this cause of corrosion. The leaching out of iron from the graphitic residue which is responsible for the characteristic appearance of this type of corrosion leads to an enriched carbon, silicon and phosphorus content in the residue as compared with the original content of these elements in the cast iron. Sulphur is usually lost to some extent but when active sulphate-reducing bacteria are present, this loss is offset by the accumulation of ferrous sulphide in the residue with a consequent increase in the sulphur content of the residue out... 

The precautions generally applicable to the preparation, exposure, cleaning and assessment of metal test specimens in tests in other environments will also apply in the case of field tests in the soil, but there will be additional precautions because of the nature of this environment. Whereas in the case of aqueous, particularly sea-water, and atmospheric environments the physical and chemical characteristics will be reasonably constant over distances covering individual test sites, this will not necessarily be the case in soils, which will almost inevitably be of a less homogeneous nature. The principal factors responsible for the corrosive nature of soils are the presence of bacteria, the chemistry (pH and salt content), the redox potential, electrical resistance, stray currents and the formation of concentration cells. Several of these factors are interrelated. 

Rogers, P., and McElroy, W. D. (1955). Biochemical characteristics of aldehyde and luciferase mutants of luminous bacteria. Proc. Natl. Acad. Sci. USA 41 67-70. 

In the very early phases of the acute inflammatory response most of the cells invading the damaged area are polymorphonuclear neutrophils, also denoted as PMNs, which serve as initial line of defense and source of proinflammatory cytokines. These cells, which usually live for 4-5 days, circulate in the blood until they are attracted by chemokines into injured tissues. Whereas physical injury does not recruit many neutrophils, infections with bacteria or fungi elicit a striking neutrophil response. The characteristic pus of a bacterial abscess is composed mainly of apoptotic (apoptosis) and necrotic PMNs. Emigration of neutrophils from the blood starts with a process denoted as margination where neutrophils come to lie at the periphery of flowing blood cells and adhere to endothelial cells (Fig. 1). L-Selectin is expressed... 

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