Microbe inhibitors

ANTTBIOTTCS - BETA-LACTAMS - BETA-LACTAMASE INHIBITORS] (Vol 3) -genetic engineering host [GENETIC ENGINEERING - MICROBES] (Vol 12)... 

Biofilms can promote corrosion of fouled metal surfaces in a variety of ways. This is referred to as microbiaHy influenced corrosion. Microbes act as biological catalysts promoting conventional corrosion mechanisms the simple, passive presence of the biological deposit prevents corrosion inhibitors from reaching and passivating the fouled surface microbial reactions can accelerate ongoing corrosion reactions and microbial by-products can be directly aggressive to the metal. 

Calcium propionate is used in bakery products as a mold inhibitor. Propionates prevent microbes from producing the energy they need, just as benzoates do. However, unlike benzoates, propionates do not require an acidic environment. 

Dorr P, Westby M, Dobbs S, et al. Maraviroc (UK-427,857), a potent, orally bioavailable, and selective small-molecule inhibitor of chemokine receptor CCR5 with broad-spectrum anti-human immunodeficiency virus type 1 activity. Anti-microb Agents Chemother 2005 49(l 1 ) 4721 —4732. 

The term allelopathy was coined by Molisch in 1937 Q). Presently, the term generally refers to the detrimental effects of higher plants of one species (the donor) on the germination, growth, or development of plants of another species (the recipient). Allelopathy can be separated from other mechanisms of plant interference because the detrimental effect is exerted through release of chemical inhibitors (allelochemicals) by the donor species. Microbes associated with the higher plants may also play a role in production or release of the inhibitors (2). 

Inhibitors from plants and their associated microbes represent a myriad of chemical compounds from the extremely simple gases and aliphatic compounds to complex polycyclic aromatic compounds. 

The classic seed burial studies of W. J. Beal and his successors have shown seeds of at least one weed species, Moth Mullein (Verbascum blattaria L.) can remain viable in soil for a peiod of 100 years, whereas three species continued to germinate after 80 years of burial (30). Weed seeds not only resist decay by soil microbes, but they vary in dormancy characteristics. There is considerable evidence that chemical inhibitors are responsible for both phenomena. Unsaturated lactones and phenolic compounds in particular, are potent antimicrobial compounds present in many seeds (4J. Fruits and seeds are also known to contain diverse germination inhibitors including phenolic compounds, flavonoids and/or their glycosides and tannins. Unique methods to destroy inhibitors could provide an excellent weed management strategy. 

Dextran is the first microbial polysaccharide produced and utilized on an industrial scale. The potential importance of dextran as a structually (and property) controlled feedstock is clearly seen in light of the recent emphasis of molecular biologists and molecular engineers in the generation of microbes for feedstock production. Dextran is employed as pharmaceuticals (additives and coatings of medications), within cosmetics, as food extenders, as water-loss inhibitors in oilwell drilling muds and as the basis for a number of synthetic resins. 

For the reasons stated above, deep intrusion of degrading microbes into polysaccharide-plastic films is demonstrably and theoretically improbable. Since starch removal does occur when the films are buried in soil, the primary mechanism must be microbial production of amylase in or near a pore, diffusion of the enzyme into pores and diffusion of soluble digestion products back to the surface where they are metabolized (Figure 3). This mechanism would be the only choice when the pore diameter is too small to admit a microbial cell (i.e., at diameters < 0.5 /im). An alternative mechanism could be diffusion of a water-soluble polysaccharide to the film surface, at which point degradation would occur. None of the materials used in these investigations showed loss of starch even when soaked in water for extended periods with microbial inhibitors present. Therefore, diffusion of amylase to the substrate rather than diffusion of the substrate to the film surface is the more likely mechanism. 

Weed seed longevity is attributed, at least in part, to inhibitors that protect the seed from decay by microbes. One of the reasons weeds pose such a serious problem is because their seeds can persist for decades. This problem might be attacked by either destroying the inhibitors or by developing strains of microbes that can destroy the seeds. 

Ruan, Y., Kotraiah, V., and Straney, D.C., Flavonoids stimulate spore germination in Fusarium solani pathogenic on legumes in a manner sensitive to inhibitors of cAMP-dependent protein kinase, Mol. Plant-Microbe Interact., 8, 929, 1995. 

Treat system with a ferrous metal corrosion inhibitor Check for the presence of hydrocarbon-utilizing microbes or sulfate-reducing microbes treat fuel/water with a biocide... 

Several classes of (3-lactamases, often encoded in transmissible plasmids, have spread worldwide rapidly among bacteria, seriously decreasing the effectivenss of penicillins and other (3-lactam anti-biotics.t y Most (3-lactamases (classes A and C) contain an active site serine and are thought to have evolved from the dd transpeptidases, but the B typey has a catalytic Zn2+. The latter, as well as a recently discovered type A enzyme,2 hydrolyze imipenem, currently one of the antibiotics of last resort used to treat infections by penicillin-resistant bacteria. Some (3-lactam antibiotics are also powerful inhibitors of (3-lactamases.U/aa/bb These antibiotics may also have uses in inhibition of serine proteasesCC/dd such as elastase. Some antibiotic-resistant staphylococci produce an extra penicillin-binding protein that protects them from beta lactams.ee Because of antibiotic resistance the isolation of antibiotics from mixed populations of microbes from soil, swamps, and lakes continues. Renewed efforts are being... 

A new halogen-containing member of the penitrem family of indole-diterpe-noids, which have insecticidal activity (1397), is thomitrem A (1466) from Penicil-lium crustosum (1398). The novel dichlorinated calmodulin inhibitor, malbrancheamide (1467), was characterized from the fungus Malbranchea auran-tiaca (1399). The microbe Streptomyces rugosporus produces pyrroindomycin B (1468), which is active against both methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci (1400). The Chinese shrub Acacia confusa has yielded the unusual chlorotryptamine alkaloid 1469, which does not appear to be an artifactual dichloromethane adduct (1401). 

L. W. Parker, and J. J. Venit, Biocatalytic preparation of a chiral synthon for a vasopeptidase inhibitor enzymatic conversion of N2-[N-phenylmethoxy)carbo-nyl] L-homocysteinyl]- l-lysine (1,1 J-disulfide to 4S-(4/,71,10aJ)]-l-octahydro-5-oxo-4-[phenylmethoxy)carbonyl]amino]-7H-pyrido-[2,l-b][l,3]thiazepine-7-carboxylic add methyl ester by a novel l -lysine e-aminotransferase, Enzyme Microb. Technd. 2000, 27, 376-389. 

The anaerobic metabolism of acrylate and 3-mercaptopropionate (3-MPA) was studied in slurries of coastal marine sediments. The rate of these compounds is important because they are derived from the algal osmolyte dimethylsulfoniopropionate (DMSP), which is a major organic sulfur compound in marine environments. Micromolar levels of acrylate were fermented rapidly in the slurries to a mixture of acetate and propionate (1 2 molar ratio). Sulfate-reducing bacteria subsequently removed the acetate and propionate. 3-MPA has only recently been detected in natural environments. In our experiments 3-MPA was formed by chemical addition of sulfide to aciylate and was then consumed by biological processes. 3-MPA is a known inhibitor of fatty acid oxidation in mammalian systems. In accord with this fact, high concentrations of 3-MPA caused acetate to accumulate in sediment slurries. At lower concentrations, however, 3-MPA was metabolized by anaerobic bacteria. We conclude that the degradation of DMSP may ultimately lead to the production of substrates which are readily metabolized by microbes in the sediments. 

Further modifications using the same strain of ODC S. cerevisiae reconstituted a bacterial/plant polyamine synthesis pathway in yeast [41], The ODC strain was transformed with plasmids encoding arginine decarboxylase and ag-matine ureohydrolase, which conferred polyamine-independent growth on the recombinant microbe. A similar construction could be used to screen for inhibitors of the homologous enzymes from Apicomplexan protozoa, which synthesize poly amines through this pathway [42]. 

The biggest concern over the use of recombinant microbes is that microbial cell walls constitute a permeability barrier for test compounds. Enzyme inhibitors that cannot accumulate in bacterial or yeast cytoplasm will appear as false nega-... 

The quantity of a protein produced by a microbe may also be important in selecting a target. The amounts of proteins vary from less than one monomer per cell to over 10,000 monomers per cell. Thus, the necessary concentrations of an inhibitor could vary over several orders of magnitude, even for an inhibitor with nanomolar binding affinity. 

Cordo, S. M., Candurra, N. A., and Damonte, E. B. 1999. Myristic acid analogs are inhibitors of Junin virus replication. Microbes Infect. 1 609-614. 

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