Bacteria sulfur

Bacteriochlorophyll- Light-absorbing pigment found in green sulfur and purple sulfur bacteria. 

In photosynthetic bacteria, HgA is variously HaS (photosynthetic green and purple sulfur bacteria), isopropanol, or some similar oxidizable substrate. [(CH2O) symbolizes a carbohydrate unit.]... 

Flowever, many photosynthetic bacteria, such as purple sulfur and green sulfur bacteria contain special bacteriochlorophyll compounds (not chlorophyll a) and carry out anoxygenic photosynthesis without producing oxygen ... 

Purple sulfur bacteria fix carbon dioxide using the Calvin-Benson cycle, but green sulfur bacteria use a completely different pathway, the reverse tricarboxylic acid cycle. Other photosynthetic bacteria use still different pathways for CO2 fixation (Perry and Staley, 1997). 

Thus, XANES spectroscopy of elemental sulfur has mainly be used to detect the particular sulfur species in samples not accessible to other spectroscopic methods, e.g., in cultures of sulfur bacteria [215, 221, 222, 224]. However, the main application is in the area of sulfur compounds with other elements. For a recent review, see [226]. 

Fig. 3. Sequence comparison of the FA/FB-binding subunits of PSl from tobacco and the RC of green sulfur bacteria with that of the 2[4Fe-4S] ferredoxin from Peptococcus aerogenes. Cysteine ligands to the right-hand cluster in the three structures of Fig. 2 (i.e., cluster Fb for the case of the FA/FB-protein) are marked by open boxes Emd residues ligating the left-hand cluster by hatched boxes.

Cluster Fx was also identified via its EPR spectral features in the RCI photosystem from green sulfur bacteria 31, 32) and the cluster binding motif was subsequently found in the gene sequence 34 ) of the (single) subunit of the homodimeric reaction center core (for a review, see 54, 55)). Whereas the same sequence motif is present in the RCI from heliobacteria (50), no EPR evidence for the presence of an iron-sulfur cluster related to Fx has been obtained. There are, however, indications from time-resolved optical spectroscopy for the involvement of an Fx-type center in electron transfer through the heliobacterial RC 56). 

Fig. 6. Sequence comparisons of Rieske proteins from spinach chloroplasts, beef heart mitochondria, green sulfur bacteria, and firmicutes. The extended insertion of proteobacterial Rieske proteins as compared to the mitochondrial one is indicated by a dotted arrow. The redox-potential-influencing Ser residue is marked by a vertical arrow. The top and the bottom sequence numberings refer to the spinach and bovine proteins, respectively. Fully conserved residues are marked by dark shading, whereas the residues conserved in the b6f-group are denoted by lighter shading.

Bacteriochlorophyll b 368, 795" Purple sulfur bacteria Brown-pink -C0CH3 -CH3 =CHCH3 -CH CHjCOO-phytyl Single Single... 

Bacteriochlorophyll c 428, 660 Green sulfur bacteria Green -C2CH3-0H -CH3 -CH2CH3 -CH CH COO-farnesyl Single Single... 

Nonomnra, Y. et al.. Spectroscopic properties of chlorophylls and their derivatives inflnence of molecnlar stmctnre on the electronic state, Chem. Phys., 220, 155, 1997. Blairkenship, R.E., Identification of key step in the biosynthetic pathway of hacteri-ochlorophyU c and its implications for other known and nirknown green sulfur bacteria, J. Bacterial., 186, 5187, 2004. 

Among the bacteria that can inhabit an oil reservoir are the sulfur bacteria that use sulfur compounds in their metabolism. These bacteria produce hydrogen sulhde, which has been responsible for extensive corrosion in the oil field. Thus exclusion of these bacteria from MEOR is highly desirable. The net effect of souring a reservoir is a decrease in the economic value of the reservoir [1835]. 

A study of photosynthetic organisms other than green plants has revealed that certain bacteria, such as the purple sulfur bacteria, utilize H2S instead of H20 as a reductant in photosynthesis. The product obtained is elemental sulfur instead of oxygen ... 

It should be recalled that for purple sulfur bacteria the equation is [Eq. (12.2)]... 

Aside from C. vinosum, type III-PHA synthases have so far been detected exclusively in the phototrophic purple sulfur bacteria such as Thiocystis viol-acea [51] and Thiocapsa pfennigii [26, 57] and in cyanobacteria such as Synechocystis sp. PCC6803 [49] or Synechococcus sp. MAI 9 [58]. In contrast, the photosynthetic nonsulfur purple bacteria possess type I-PHA synthases. 

Fig. 5.7. In green sulfur bacteria and in some archaebacteria, a reverse citric acid cycle is used for the assimilation of C02. It must be assumed that this was the original function of the citric acid cycle that only secondarily took over the role as a dissimulatory and oxidative process for the degradation of organic matter. A major enzyme here is 2-oxoglutarate ferredoxin for C02 fixation. Note that it, like several other enzymes in the cycle, uses Fe/S proteins. One is the initial so-called complex I which has eight different Fe/S centres of different kinds but no haem (see also other early electron-transfer chains, e.g. in hydrogenases).

Prokaryote heterotrophs precursors of cyanobacteria. Stromatolites. Sulfur bacteria Beginning of photosynthesis Traces... 

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