Heliobacterium

Desulfovibrio Heliobacillus Heliobacterium Heliophilum Rhodobacter Rhodomicrobium Rhodopila Rhodopseudomonas Rhodospirillum Thiocapsa ... 

In the BChl g containing heliobacteria Heliobacillus mobilis and Heliobacterium chlorum symmetric dimers for the primary donor radical cation PgJ5 have been found based on EPR and ENDOR data.85 This symmetric dimer is consistent with the homodimeric structure of the RC. The same reason was invoked to explain the high symmetry of the donor radical-cation Pgg5 in green sulfur bacteria, which is made up from a BChl a dimer.86 For a review see reference 87. Note that these RCs belong to the type I RCs. 

Fig. 1. Dendrogram of relationships among photosynthetic prokaryotes and their relatives, after Stackebrandt and Woese [2], Five bacterial phyla [1] containing photosynthetic members are shown. The exact relationship of Heliobacterium chlorum to the gram-positive bacteria is not yet known. Not shown are the other five phyla without known photosynthetic-members peptidoglycan-less bacteria bacteroids, cytophagas and flavobacteria spirochaetes and leptospiras bdellovibrios, myxococci, and certain S and SOj reducers and Deinococcus. PS = photosynthetic for further explanation, see text.

Gram-positive line H. chlorum) Heliobacterium Unicellular rods... 

In the recently discovered photosynthetic bacterium Heliobacterium chlorum, which has a BChl g complex as primary donor, the primary acceptor is also a ferredoxin-type molecule with g values 2.04, 1.94 and 1.88 [40]. An earlier acceptor could be photoaccumulated at very low (< —620 mV) redox potential. It had a near-Gaussian EPR line at g = 2.0038 with AB = 15 G at X-band and 18 G at Q-band [40]. 

H Gest and JR Favinger (1983) Heliobacterium chlorum, an anoxygenic brownish-green photosynthetic bacterium containing a new form ofbacteriochlorophyllArch Microbiol 136 11-16... 

Fig. 5. Spectra recorded with a dual diode array detecting system in a continuum experiment. Membranes of the heliobacterium Heliobacillus mobilis were excited at 590 nm with a repetition rate of 540 Hz (full width at half-maximum 200 fsec). Spectra were taken at the indicated times after excitation. The authors conclude that this early time spectral evolution is probably due to the excitation distribution among different spectral forms. [With permission from S. Lin, H.-C. Chiou, and R. E. Blankenship, in Research in Photosynthesis, Volume 1 (N. Murata, ed.), p. 417. Kluwer Academic Press, Dordrecht, The Netherlands, 1992.]...

TRIPLETS IN THE ANTENNA AND REACTION CENTRE OF HELIOBACTERIUM CHLORUM AT LOW TEMPERATURE... 

The heliobacteria are a seperate group of photosynthetic bacteria which contain bacteriochloro-phyll g as their major pigment (1). Only three species have been isolated so far Heliobacterium chlorum. Heliobacillus mobilis and Heliospirilum gestii. 

All experiments were done with membrane fragments of Heliobacterium chloruMy prepared as described elsewhere (M.R. Fischer, manuscript in preparation). 

Heliobacterium fasciculum (Latin fasciculus, bundle), was isolated from Tanzanian paddy field soil. The rods are 0.8-1 X 8-20 urn, motile with thick, polar ( ) flagella, and associate in parallel motile bundles (Fig. 5), which swim with a characteristic rolling motion and are phototactic. 

Excitation Transfer and Charge Separation in Heliobacterium Chlorum at 15 K 185... 

Triplets in the Antenna and Reaction Centre of Heliobacterium Chlorum at Low Temperature 189... 

Noguchi, T., Fukami, Y., Oh-Oka, H., Inoue, Y. FouiiCT transform infrared study on the primary donor P798 of Heliobacterium modesticaldum Cysteine S-H coupled to P798 and molecular interactions of carbonyl groups. Biochemistry 36, 12329-12336 (1997)... 

Desulfitobacterium dehalogenans Heliobacterium Polychlorinated biphenyls Wiegel et al. (1999)... 

Desulfitobacterium hafniense Heliobacterium 3-Chloro-4-hydroxy-phenylacetate Christiansen et al. (1998)... 

In parallel with molecular nonculture methods, the well-established methods of enrichment culture are more frequently being applied under anaerobic and other nonstandard conditions in an effort to obtain novel microbial types. This approach also suggests that biodegradative capabilities are more widespread in the microbial world than has been appreciated by some. For example, halophiles have been identified which metabolize nitroarenes, and members of the Heliobacterium group are known that catabolize polychlorinated biphenyls (PCBs) and chlorophenols (O Table 15.2). These and other recent observations are expanding the taxonomic range of bacteria that catabolize environmental pollutants. Further experiments are likely to expand this further. 

Since the discovery of the photosynthetic bacterium Heliobacterium (H.) chlorum [1], the first identified species of the family of the Heliobacteriaceae, this species has been investigated intensively. Membranes of //. chlorum contain bacteriochlorophyll (BChl) g as major photosynthetic pigment [2]. They have about 35 antenna BChl g molecules per reaction center [3], which absorb close to 790 nm (Qy transition) and 575 nm (Qx transition). At temperatures below 77 K the Qy band can be roughly resolved into three spectral components, centered at 778, 793 and 808 nm [4]. 

Triplet-minus-singlet Absorbance Difference Spectroscopy of Heliobacterium chlorum Monitored with Absorbance-detected Magnetic Resonance J. Vrieze, E.J. van de Meent, A.J. Hoff. 67... 

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