Acids metabolic activity

The source of free radicals is multiplied under these circumstances, arachidonic acid metabolism, activation of xanthine oxidase, perturbation of electron flow within the respiratory chain, and NOS activation. Structurally, excitotoxicity is generally described as a necrotic process involving initial swelling of the cell and of the endoplasmic reticulum, clumping of chromatin, followed by swelling of the... 

Forsyihia sp. Allergic and inflammatory Forsythiaside Antiinflamatory Effect on arachidonic acid metabolism Active as inhibitor of 5-HETE and LTB4 in rat peritoneal [44]... 

In man, the metabolic pathways of mepirizole were distinct from those in experimental animals, since hydroxylation on each of the aromatic rings did not occur in man. Compound (752) was obtained by oxidation of the 3-methyl group to the carboxylic acid (a similar process occurs with 5-methylpyrazole-3-carboxylic acid, an active metabolite of 3,5-dimethylpyrazole). However, the carboxylic acid metabolite of mepirizole had no analgesic activity and did not decrease blood glucose. 

A subclass of lyases, involved in amino acid metabolism, utilizes pyridoxal 5-phosphate (PLP, 3-hydroxy-2-methyl-5-[(phosphonooxy)methyl]-4-pyridinecarbaldehyde) as a cofactor for imine/ enamine-type activation. These enzymes are not only an alternative to standard fermentation technology, but also offer a potential entry to nonnatural amino acids. Serine hydroxymethyl-tansferase (SHMT EC 2.1.2.1.) combines glycine as the donor with (tetrahydrofolate activated) formaldehyde to L-serine in an economic yield40, but will also accept a range of other aldehydes to provide /i-hydroxy-a-amino acids with a high degree of both absolute and relative stereochemical control in favor of the L-erythro isomers41. 

Acyl-CoAs are the activated intermediates of fatty acid metabolism formed by the condensation of fatty acids with Coenzyme A. 

Hokum, J.A.M. Winter, K. (1982). Activity of enzymes of carbon metabolism during the induction of Crassulacean acid metabolism in Mesembryanthemum crystallinum L. Planta, 155, 8-16. 

By interfering with any one of the many phases associated with these second messenger pathways, toxins may alter channel gating. For example, the blue green algal toxins, aplysiatoxin, and lyngbyatoxin bind to and activate protein kinase C in a manner similar to phorbol esters (73). They also stimulate arachidonic acid metabolism (74). The coral toxin, palytoxin, also stimulates arachidonic acid breakdown albeit by an unknown mechanism (74) and affects other biochemical activities of the cell (see chapters by Fujiki et al., Wattenberg et al., and Levine et al., this volume). 

Palytoxin s properties of stimulating arachidonic acid metabolism were decreased > 90% after exposure to 0.1 N HCl for 60 min at 37 C and decreased about 75% after exposure to 0.01 N HCl for 60 min at 50 C, but these biologic properties were stable to boiling in H2O for 60 min. Palytoxin s serologic activities were stable to these treatments. 

Furthermore, we found that the two types of tumor promoters induced common biological effects, such as irritation of mouse ear, and stimulation of prostaglandin E2 production and of arachidonic acid metabolism in rat macrophages. These common effects seem to be the most essential biological activities in tumor promotion (6). 

In media selective for enterobacteria a surface-active agent is the main selector, whereas in staphylococcal medium sodium and lithium chlorides are the selectors staphylococci are tolerant of salt concentrations to around 7.5%. Mannitol salt, Baird-Parker (BP) and Vogel-Johnson (VJ) media are three examples of selective staphyloccocal media. Beside salt concentration the other principles are the use of a selective carbon source, mannitol or sodium pyruvate together with a buffer plus acid-base indicator for visualizing metabolic activity and, by inference, growth. BP medium also contains egg yolk the lecithin (phospholipid) in this is hydrolysed by staphylococcal (esterase) activity so that organisms are surrounded by a cleared zone in the otherwise opaque medium. The United States Pharmacopeia (1990) includes a test for staphylococci in pharmaceutical products, whereas the British Pharmacopoeia (1993) does not. 

The selective utilization of prebiotics by some, but not all, of the resident species alters the assemblages, densities and metabolic activities of the GIT bacteria. Of importance is the ability of prebiotics to increase the proportion of the resident bacteria represented by the lactic acid producing bacteria (LAB), resulting in changes of GIT and systemic functions (Swanson et al.. 

Bioassay for metabolic activity (glycolytic and acid phosphatase activity) of peritoneal-exudative cells after treatment with polysaccharide practions. 

The reported (14) mechanisms of action of allelochemlcals Include effects on root ultrastructure and subsequent Inhibition of Ion absorption and water uptake, effects on hormone-induced growth, alteration of membrane permeability, changes In lipid and organic acid metabolism, inhibition of protein synthesis and alteration of enzyme activity, and effects on stomatal opening and on photosynthesis. Reduced leaf water potential Is one result of treatment with ferulic and p-coumaric acids (15). Colton and Einhellig (16) found that aqueous extracts of velvetleaf (Abutllon theophrastl Medic.) Increased diffusive resistance In soybean fGlycine max. (L.) Merr.] leaves, probably as a result of stomatal closure. In addition, there was evidence of water stress and reduced quantities of chlorophyll In Inhibited plants. 

Fortuitous or co-metabolic biodegradation may account for a significant portion of the removal of xenobiotics in the environment.24 Numerous examples of co-metabolic activity have been described for pure substrates,22 but co-metabolism has been very difficult to demonstrate in mixed-substrate, mixed-culture systems, because products of the co-metabolic reactions of one species may be degraded by another.24 To encourage co-metabolism, easily degradable co-substrates should be included in the leachate prior to biological treatment. Fatty acids, which often occur in landfill leachates, may fulfill this requirement. 

MISCELLANEOUS ARYLALKANOIC ACIDS It has been known for some time that thyroxine, and related compounds such as liothyronine (88) are effective in lowering serum cholesterol. The normal metabolic activity of this class of thyroid active compounds has precluded their use as hypocholesterol-emic agents. 

---