Process, absorption anaerobic

The recovered metabolites and their rate of formation closely followed previously reported values for anaerobic soil and water, substantiating the utility of the model ecosystem for metabolic studies. However, residues in the biomass were apparently derived primarily through absorption from water rather than metabolism within the organisms themselves. It was concluded that the scaled-up model ecosystem is more useful for studying system process than processes that function in individual components of the environment. 

The presence of permanent [Fe2S2] clusters in holo-NifU impeded spectroscopic characterization of transient clusters assembled in a NifS-mediated process. However, unambiguous evidence for NifS-directed assembly of oxidatively and reductively labile [Fe2S2] " clusters on NifU-1 was obtained using the combination of UV-visible absorption and resonance Raman spectroscopies (Yuvaniyama et al. 2000). The anaerobic reaction mixture involved NifU ferric ammonium citrate P-mercaptoethanol l-cysteine NifS in a 50 100 5000 1000 1 ratio. The presence of catalytic amounts of NifS facilitated meaningful UV-visible absorption results and monitoring the time course of cluster assembly. Although ferric ammonium citrate was used for these cluster assembly studies, control experiments... 

Addition of base or acid had, however, a significant impact on the stability and yield of the characteristic 1080 nm absorption band. A semilogarithmic correlation between the proton concentration and the intensity of the fullerene 7t-radical anion band (1080 nm) is observed in anaerobic aqueous solutions. This observation has been ascribed to a reversible protonation of Ceo /Y-CD. Experimental proof for this assumption was brought forward by the fact that the 1080 nm absorption, in an alkaline solution (pH 10), diminished upon acidifying (pH 3) and was completely restored upon addition of base (pH 10). The reversible protonation process gives rise to a pKa of 4.5. 

It is a common statement that life is always connected to the production of heat. That is true in most cases, perhaps with one (known) exception, i.e. the anaerobic production of CH and CO2 from acetate. In this process the entropy term outweighs the heat term and, at least in theory, life could be connected to net heat absorption [23]. However, if we ignore this exception and instead concentrate on what part of metabolism generates the heat. Is it due to catabolic or anabolic reactions The answer is in fact both catabolism and anabolism is involved. 

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