Specific inhibition of antenna bacteriochlorophyll synthesis in Chlorobium vibrioforme by anesthetic gases

Journal Article · Thu Mar 01 00:00:00 EST 1990 · Journal of Bacteriology; (USA)

OSTI ID:7189925

Ormerod, J G; Nesbakken, T ^[1]; Beale, S I ^[2]

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1. Univ. of Oslo, Norway (USA)
2. Brown Univ., Providence, RI (USA)

The green sulfur bacterium Chlorobium vibrioforme contains two types of bacteriochlorophll (Bchl). The minor pigment, Bchl a, is associated primarily with the cell membrane and its reaction centers; and the major light-harvesting antenna pigment, Bchl d, is found primarily in the chlorosomes, which are attached to the inner surface of the cell membrane. Anesthetic gases, such as N{sub 2}O, ethylene, and acetylene, were found to inhibit the synthesis of Bchl d, but not of Bchl a, thus allowing the cells to grow at high light intensities with a greatly diminished content of antenna pgiment. Chlorosomes were absent or sparse in inhibited cells. Porphyrins accumulated in the inhibited cells. Result suggest that the gases act at a step in pigment biosynthesis that affect the utilization of the major one was identified as the Bchl precursor magnesium-protoporphyrin IX monomethyl ester (Mg-PPME) for isocyclic ring formation. Synthesis of Bchl d and Bchl a may be differentially affected by the gases because of compartmentation of their biosynthetic apparatus or because competition for precursors favors Bchl a synthesis. An ethephon-resistant mutant strain was isolated by selection for growth in dim, long-wavelength light. The mutant cells were also resistant to acetylene, but not to N{sub 2}O. The ability to reversibly generate viable Chlorobium cells that lack antenna pigments may be useful in photosynthesis research. The ethephon-and acetylene-resistant strain may be useful in the study of the enzymes and genes that are involved in the biosynthetic step that the gases affect.

• DOE Contract Number: FG02-88ER13918
• OSTI ID: 7189925
• Journal Information: Journal of Bacteriology; (USA), Vol. 172:3; ISSN 0021-9193
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACETYLENE
BIOLOGICAL EFFECTS
ETHYLENE
NITROUS OXIDE
PHOTOSYNTHETIC BACTERIA
PHOTOSYNTHESIS
INHIBITION
PHOTOSYNTHETIC REACTION CENTERS
PROTOPORPHYRINS
ALKENES
ALKYNES
CARBOXYLIC ACIDS
CHALCOGENIDES
CHEMICAL REACTIONS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
NITROGEN COMPOUNDS
NITROGEN OXIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PIGMENTS
PORPHYRINS
SYNTHESIS
560300* - Chemicals Metabolism & Toxicology