Influence of pH, O/sub 2/, and temperature on the absorption properties of the secondary light-harvesting antenna in members of the family Rhodospirillaceae

Journal Article · Sun Sep 01 04:00:00 EDT 1985 · J. Bacteriol.; (United States)

OSTI ID:6378374

Uffen, R L

Results show that holochrome B800-860 (LH II) exhibits unstable light absorption properties in whole cells. This was observed in Rhodopseudomonas capsulata grown anaerobically in light in weakly buffered carbohydrate medium. The whole cell spectrophotometric changes were attributed to mild acid conditions generated during sugar metabolism. LH II absorbency was also destroyed in both R. capsulata and Rhodopseudomonas gelatinosa when cultures growing at neutral pH were acidified to a pH value around 5.0. In contrast, during the same time period of exposure to pH 5.0, only a 50% decrease in Rhodopseudomonas sphaeroides LH II B800 absorbency was measured. At neutral pH, LH II absorbency in suspensions of nongrowing Rhodopseudomonas spp. was also sensitive to O/sub 2/ exposure and to incubation at 30 to 40/sup 0/C. During treatment with O/sub 2/, the rate of LH II B800 absorption decrease in R. gelatinosa and R. sphaeroides was 60 and 40% per h, respectively, compared with their absorbency maximum around 860 nm. Both 860-nm absorbency and the total bacteriochlorophyll content of the cells remained unchanged. On the other hand, no significant decrease in B800 of LH II in R. capsulata occurred during O/sub 2/ exposure, but a 20% absorption decay rate per h of B800 was observed in cells incubated anaerobically at 40/sup 0/C. The near-infrared absorption spectrum of Rhodospirillum rubrum, which does not form LH II, was not significantly influenced by these different pH, aerobic, or temperature conditions.

• Research Organization: Michigan State Univ., East Lansing
• OSTI ID: 6378374
• Journal Information: J. Bacteriol.; (United States), Journal Name: J. Bacteriol.; (United States) Vol. 163:3; ISSN JOBAA
• Country of Publication: United States
• Language: English

Related Subjects

550200 -- Biochemistry
550700* -- Microbiology
59 BASIC BIOLOGICAL SCIENCES
ANAEROBIC CONDITIONS
BACTERIA
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CHLOROPHYLL
ELEMENTS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INFRARED SPECTRA
MEMBRANES
MICROORGANISMS
NONMETALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN
PH VALUE
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PHOTOSYNTHETIC MEMBRANES
PHOTOSYNTHETIC REACTION CENTERS
PHYTOCHROMES
PIGMENTS
PORPHYRINS
RESPONSE MODIFYING FACTORS
RHODOPSEUDOMONAS
RHODOSPIRILLUM
SORPTIVE PROPERTIES
SPECTRA
SURFACE PROPERTIES
SYNTHESIS
TEMPERATURE EFFECTS