Bacteria respiration

Bacteria play an important role in the redox chemistry of nitrogen species in seawater. Starting with PON, the first step is remineralisation in which PON is converted to DON. The breakdown of some of the DON to DIN follows with the first product being NH3 the process is relatively rapid and known as ammonification. NH3 is protonated to a limited extent in seawater, giving rise to NH4 ions. Nitrification is the stepwise oxidation of NH4 to N02 and eventually to N03. Denitrification, the reduction of nitrogen species to N2, can occur under conditions of hypoxia or anoxia. In such cases, bacteria respire organic material using N03 and NO2 as electron acceptors. 

In aerobic organisms, the terminal oxidant is, of course, oxygen. However, some species of bacteria respire anaerobically and are able to use inorganic oxyanions (nitrate or sulfate) as terminal oxidants. The translocation of protons across the inner mitochondrial membrane accompanies the electron transfers that... 

FIGURE 4 Three models that explain how bacteria respire minerals. 

SECM measurements performed on E. coli containing substrates have targeted bacteria respiration redox mediator interactions with bacteria or the relationship between SECM measured currents and protein activity. 

We have shown that TNBT has to be added in presence of O2 to act as an ATP-ase inhibitor. Its action is however irreversible since anaerobic conditions do not restore ATP synthesis. The induction of TNBT inhibition is not related to the oxydo-state of the quinone pool or to the presence of a high membrane potential during active bacteria respiration. 

Obligate aerobe Bacteria which require the presense of oxygen, such as Pseudomonas flourescens. A few strains of this species are capable of utilizing nitrate to allow anaerobic respiration. 

Fermentation occurs naturally in various microorganisms such as bacteria, yeasts, fungi and in mammalian muscle. Yeasts were discovered to have connection with fermentation as observed by Louis Pasteur and originally defined as respiration without air. However, it does not have to always occur in anaerobic condition. For example, starch when fermented under... 

In contrast to common usage, the distinction between photosynthetic and respiratory Rieske proteins does not seem to make sense. The mitochondrial Rieske protein is closely related to that of photosynthetic purple bacteria, which represent the endosymbiotic ancestors of mitochondria (for a review, see also (99)). Moreover, during its evolution Rieske s protein appears to have existed prior to photosynthesis (100, 101), and the photosynthetic chain was probably built around a preexisting cytochrome be complex (99). The evolution of Rieske proteins from photosynthetic electron transport chains is therefore intricately intertwined with that of respiration, and a discussion of the photosynthetic representatives necessarily has to include excursions into nonphotosynthetic systems. 

SRB, a diverse group of anaerobic bacteria isolated from a variety of environments, use sulfate in the absence of oxygen as the terminal electron acceptor in respiration. During biofilm formation, if the aerobic respiration rate within a biofilm is greater than the oxygen diffusion rate, the metal/biofilm interface can become anaerobic and provide a niche for sulfide production by SRB. The critical thickness of the biofilm required to produce anaerobie conditions depends on the availability of oxygen and the rate of respiration. The corrosion rate of iron and copper alloys in the presence of hydrogen sulfide is accelerated by the formation of iron sulfide minerals that stimulate the cathodic reaction. 

Coates JD, KA Cole, R Chakraborty, SM O Connor, LA Achenbach (2002) Diversity and ubiquity of bacteria capable of utilizing humic substances as electron donors for anaerobic respiration. Appl Environ Microbiol 68 2445-2452. 

Logan BE, H Zhang, P Mulvaney, MG Milner, IM Head, RF Unz (2001) Kinetics of perchlorate- and chlorate-respiring bacteria. Appl Environ Microbiol 67 2499-2506. 

Brennan RA, RA Sanford (2002) Continuous steady-state method using Tenax for delivering tetrachloro-ethene to chloro-respiring bacteria. Appl Environ Microbiol 68 1464-1467. 

A. Zimmermann, R. Iturriaga, and J. Beckcr-Birk, Simultaneous determination of the total number of aquatic bacteria and the number thereof involved in respiration, Appl. Environ. Microbial 36 926 (1978). 

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