Metabolism, anaerobic, molecular

Molecular hydrogen plays a major role on the oxidation-reduction processes involved in bacterial energetics, as well as in the degradation and conversion of biomass related with all major elemental cycles. Hydrogenase has a key role on this process and catalyzes the reversible oxidation of dihydrogen, important in bacterial anaerobic metabolism ... 

Molecular Hydrogen Electron Currency in Anaerobic Metabolism... 

Diaz, F. and Komuniecki, R.W. (1994) Pyruvate dehydrogenase complexes from the equine nematode, Parascaris equorum, and the canine cestode, Dipylidium caninum, helminths exhibiting anaerobic mitochondrial metabolism. Molecular and Biochemical Parasitology 67, 289-299. 

Dibenzylsulfide. Figure 13 shows the identified products of aerobic and anaerobic metabolism of dibenzylsulfide. Babienzien et al. (68) incubated this substrate with a mixed population of aerobic bacteria and detected several water-soluble organic products. However, only benzylmercaptoacetic acid was identified. Kohler et al. (49) incubated dibenzylsulfide with a selected strain of Desulfovibrio utilizing molecular hydrogen under anaerobic conditions where sulfate served as the terminal electron acceptor. Toluene and benzylmercaptan were identified as metabolites. In addition, 35S-sulfide was found in cultures incubated with 35S-dibenzylsulfide. 

Recent progress in molecular biology on the anaerobic metabolism of Escherichia coli has elucidated the enzymes and genes responsible for fermentative hydrogen production (1,2). Ecoli produces hydrogen by mixed acid fermentation, mainly from glucose. In Ecoli,... 

Hydrogenases catalyze the interconversion of protons and molecular hydrogen during anaerobic metabolism in bacteria, Archae, and Eukarya (5) ... 

Mattheis JP, Roberts RG (1993) Fumigation of sweet cherry (Prunus avium Bing) fruit with low molecular weight aldehydes for postharvest decay control. Plant Dis 77 810-814 Mattheis JP, Buchanan DA, Fellman JK (1991) Change in apple fruit volatiles after storage in atmospheres inducing anaerobic metabolism. J Agric Food Chem 39 1602-1605... 

Independently of strictly enzymatically caused cleavages, hydrolytic processes are often catalyzed in the polymer by a reduction in pH-value. This value can shift to a pH range < 7 due to secondary chemical reactions caused by microorganisms, if low-molecular acids are simultaneously formed by anaerobic metabolism. A principle distinction is made between two mechanisms of enzymatic action hydrolysis and oxidation [889]. 

NADH, which enters the Krebs cycle. However, during cerebral ischaemia, metabolism becomes anaerobic, which results in a precipitous decrease in tissue pH to below 6.2 (Smith etal., 1986 Vonhanweh etal., 1986). Tissue acidosis can now promote iron-catalysed free-radical reactions via the decompartmentalization of protein-bound iron (Rehncrona etal., 1989). Superoxide anion radical also has the ability to increase the low molecular weight iron pool by releasing iron from ferritin reductively (Thomas etal., 1985). Low molecular weight iron species have been detected in the brain in response to cardiac arrest. The increase in iron coincided with an increase in malondialdehyde (MDA) and conjugated dienes during the recirculation period (Krause et al., 1985 Nayini et al., 1985). 

Komuniecki, R. and Komuniecki, P.R. (1995) Aerobic-anaerobic transitions in energy metabolism during the development of the parasitic nematode Ascaris suum. In Boothroyd, J.C. and Komuniecki, R. (eds) Molecular Approaches to Parasitolog. Wiley-Liss, New York, pp. 109-121. 

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