Differentiation of the membrane system in cells of Rhodopseudomonas capsulata after transition from chemotrophic to phototrophic growth conditions

1982 ◽  
Vol 131 (4) ◽  
pp. 313-322 ◽  
Author(s):  
Norbert Kaufmann ◽  
Horst-Helwig Reidl ◽  
Jochen R. Golecki ◽  
Augusto F. Garcia ◽  
Gerhart Drews
Keyword(s):  
Membrane System ◽  
Growth Conditions ◽  
Rhodopseudomonas Capsulata ◽  
Phototrophic Growth ◽  
In Cells

scholarly journals Changes in the acyl lipid composition of photosynthetic bacteria grown under photosynthetic and non-photosynthetic conditions

1979 ◽  
Vol 181 (2) ◽  
pp. 339-345 ◽  
Author(s):  
Nicholas J. Russell ◽  
John L. Harwood
Keyword(s):  
Fatty Acids ◽  
Photosynthetic Bacteria ◽  
Rhodospirillum Rubrum ◽  
Relative Proportion ◽  
Photosynthetic Apparatus ◽  
Growth Conditions ◽  
Rhodopseudomonas Capsulata ◽  
Rhodopseudomonas Sphaeroides ◽  
Acyl Lipids ◽  
And Function

The acyl lipids and their constituent fatty acids were studied in the photosynthetic bacteria Rhodospirillum rubrum, Rhodopseudomonas capsulata and Rhodopseudomonas sphaeroides, which were grown under photosynthetic and non-photosynthetic conditions. The major lipids were found to be phosphatidylethanolamine, phosphatidylglycerol and cardiolipin in each bacterium. The two Rhodopseudomonas species also contained significant quantities of phosphatidylcholine. Other acyl lipids accounted for less than 10% of the total. On changing growth conditions from non-photosynthetic to photosynthetic a large increase in the relative proportion of phosphatidylglycerol was seen at the expense of phosphatidyl-ethanolamine. In Rhodospirillum rubrum the fatty acids of the major phospholipids showed an increase in the proportion of palmitate and stearate and a decrease in palmitoleate and vaccenate on changing growth conditions to photosynthetic. In contrast, the exceptionally high levels (>80%) of vaccenate in individual phospholipids of Rhodopseudomonas capsulata and Rhodopseudomonas sphaeroides were unaffected by changing growth conditions to photosynthetic. Analysis of the lipids of chromatophores, isolated from the three bacteria, showed that these preparations were enriched in phosphatidylglycerol. The large increase in this phospholipid, seen during growth under photosynthetic conditions, appeared, therefore, to be due to a proliferation of chromatophore membranes. Possible roles for acyl lipids in the formation and function of the photosynthetic apparatus of bacteria are discussed.

scholarly journals Superoxide dismutase, catalase, and peroxidase in ammonium-grown and nitrogen-fixing Azospirillum brasilense

1984 ◽  
Vol 30 (10) ◽  
pp. 1222-1228 ◽  
Author(s):  
Richard W. Clara ◽  
Roger Knowles
Keyword(s):  
Superoxide Dismutase ◽  
Electron Acceptor ◽  
Azospirillum Brasilense ◽  
Polyacrylamide Gel Electrophoresis ◽  
Growth Conditions ◽  
Sod Activity ◽  
Batch Cultures ◽  
Physiological Conditions ◽  
Azospirillum Brasilense Sp7 ◽  
In Cells

Superoxide dismutase (SOD), catalase (CAT), and peroxidase (PER) activities were studied in ammonium-grown and N2-fixing batch cultures of Azospirillum brasilense Sp7. PER activity, as measured using o-dianisidine or 3,3′-diaminobenzidine as the H donor, was not significant in most growth conditions. SOD activity increased in response to higher O2 concentrations but was also present in cells grown anaerobically with nitrate [Formula: see text] or nitrous oxide (N2O) as electron acceptor. CAT activity increased at lower O2 concentrations and was highest in cells grown anaerobically with [Formula: see text] as electron acceptor. Polyacrylamide gel electrophoresis of cell-free extracts revealed only one band of SOD activity under each of the physiological conditions employed, compared with three for aerobically grown Escherichia coli K12. This band proved to be iron-containing SOD (FeSOD) on the basis of inhibitor sensitivity.

scholarly journals Optimizing bioreactor growth of the smallest eukaryote

2018 ◽  
Author(s):  
Chuck R. Smallwood ◽  
Eric A. Hill ◽  
William Chrisler ◽  
Jory Brookreson ◽  
James E. Evans
Keyword(s):  
Growth Conditions ◽  
Energy Resources ◽  
Total Biomass ◽  
Nutrient Requirements ◽  
Free Living ◽  
Nutrient Pools ◽  
Photosynthetic Organisms ◽  
Ostreococcus Tauri ◽  
Phototrophic Growth ◽  
Doubling Times

AbstractPhotosynthetic organisms are adept at circumventing nutrient deprivation. Microalgae in particular present novel adaptations to nutrient and light starvation since they can scavenge external and internal nutrient pools to redistribute energy resources for survival. In this report, a turbidostatic photobioreactor was used to characterize environmental conditions and nutrient requirements for cultures of the smallest free-living eukaryote Ostreococcus tauri. Optimized growth conditions were identified that enable 4-times faster phototrophic growth-rates while increasing total biomass 10-fold. By achieving phototrophic doubling times shorter than 6 hours, these results highlight the potential of this smallest eukaryote for future industrial bioproduct applications.

ABF1 is a phosphoprotein and plays a role in carbon source control of COX6 transcription in Saccharomyces cerevisiae

1992 ◽  
Vol 12 (9) ◽  
pp. 4197-4208
Author(s):  
S Silve ◽  
P R Rhode ◽  
B Coll ◽  
J Campbell ◽  
R O Poyton
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Glucose Repression ◽  
Carbon Sources ◽  
Growth Conditions ◽  
Source Control ◽  
Specific Target Gene ◽  
Phosphorylation Pattern ◽  
Nonfermentable Carbon Source ◽  
In Cells

Previously, we have shown that the Saccharomyces cerevisiae DNA-binding protein ABF1 exists in at least two different electrophoretic forms (K. S. Sweder, P. R. Rhode, and J. L. Campbell, J. Biol. Chem. 263: 17270-17277, 1988). In this report, we show that these forms represent different states of phosphorylation of ABF1 and that at least four different phosphorylation states can be resolved electrophoretically. The ratios of these states to one another differ according to growth conditions and carbon source. Phosphorylation of ABF1 is therefore a regulated process. In nitrogen-starved cells or in cells grown on nonfermentable carbon sources (e.g., lactate), phosphorylated forms predominate, while in cells grown on fermentable carbon sources (e.g., glucose), dephosphorylated forms are enriched. The phosphorylation pattern is affected by mutations in the SNF1-SSN6 pathway, which is involved in glucose repression-depression. Whereas a functional SNF1 gene, which encodes a protein kinase, is not required for the phosphorylation of ABF1, a functional SSN6 gene is required for itsd ephosphorylation. The phosphorylation patterns that we have observed correlate with the regulation of a specific target gene, COX6, which encodes subunit VI of cytochrome c oxidase. Transcription of COX6 is repressed by growth in medium containing a fermentable carbon source and is derepressed by growth in medium containing a nonfermentable carbon source. COX6 repression-derepression is under the control of the SNF1-SSN6 pathway. This carbon source regulation is exerted through domain 1, a region of the upstream activation sequence UAS6 that binds ABF1 (J. D. Trawick, N. Kraut, F. Simon, and R. O. Poyton, Mol. Cell Biol. 12:2302-2314, 1992). We show that the greater the phosphorylation of ABF1, the greater the transcription of COX6. Furthermore, the ABF1-containing protein-DNA complexes formed at domain 1 differ according to the phosphorylation state of ABF1 and the carbon source on which the cells were grown. From these findings, we propose that the phosphorylation of ABF1 is involved in glucose repression-derepression of COX6 transcription.

scholarly journals Effect of Anaerobiosis on Expression of Virulence Factors in Vibrio cholerae

2004 ◽  
Vol 72 (7) ◽  
pp. 3961-3967 ◽  
Author(s):  
H. H. Krishnan ◽  
Amalendu Ghosh ◽  
Kalidas Paul ◽  
Rukhsana Chowdhury
Keyword(s):  
Vibrio Cholerae ◽  
Virulence Factors ◽  
Regulatory Gene ◽  
Growth Conditions ◽  
Anaerobic Growth ◽  
Anaerobic Conditions ◽  
Regulatory Cascade ◽  
Significant Difference ◽  
In Cells

ABSTRACT In Vibrio cholerae, the transmembrane DNA binding proteins, ToxR and TcpP, activate expression of the regulatory gene toxT in response to specific environmental signals. The resulting enhanced level of ToxT leads to a coordinated increase in the production of a subset of virulence factors, including cholera toxin (CT) and toxin-coregulated pilus (TCP). The effect of anaerobiosis on expression of the V. cholerae virulence regulatory cascade was examined. The expression of the major regulatory genes, tcpP, toxR, and toxT, in anaerobically grown V. cholerae was comparable to that in cells grown under aerobic conditions, and no significant difference in the ToxT-dependent expression of tcpA was detected when aerobic and anaerobic cultures were compared. However, in spite of the presence of functional ToxT, ctxAB expression was drastically reduced, and practically no CT was detected in cells grown under anaerobic conditions. In a V. cholerae hns mutant, however, high levels of ctxAB expression occurred even under anaerobic conditions. Also, deletion of the H-NS binding site from the ctxAB promoter eliminated anaerobic repression of ctxAB expression. These results suggest that H-NS directly represses ctxAB expression under anaerobic growth conditions. It has been reported that in the first stage of infection of infant mice by V. cholerae, tcpA is expressed but ctxAB expression is shut off (S. H. Lee, D. L. Hava, M. K. Waldor, and A. Camilli, Cell 99: 625-634, 1999). This pattern is similar to the pattern in anaerobic cultures of V. cholerae. Under all other in vitro conditions, ctxAB and tcpA are known to be coordinately expressed.

Tetrapyrrol Derivatives Shown by Fluorescence Emission and Excitation Spectroscopy in Cells of Rhodopseudomonas capsulata Adapting to Phototrophic Conditions

1982 ◽  
Vol 37 (3-4) ◽  
pp. 199-204 ◽  
Author(s):  
Jürgen Beck ◽  
Gerhart Drews
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Fluorescence Emission ◽  
Bacteriochlorophyll A ◽  
Rhodopseudomonas Capsulata ◽  
Cell Protein ◽  
In Cells

Abstract Aerobically in the dark grown cells were incubated semiaerobically (30 min) and afterwards 180 min anaerobically in the light During phototrophic induction the bacteriochlorophyll concentra­ tion increased from 0.26 to 2.10 nmol/mg cell protein.In samples taken at different times after lowering of oxygen partial pressure the following tetrapyrrol derivatives were identified by fluorescence emission and excitation spectroscopy at 1.7 K: Mg-protoporphyrin EX-monomethylester, Mg-2,4-divinylphaeoporphyrin a5-monomethylester, 2-de-vinyl-2 -hydroxyethyl-chlorophyllide, 2 -devinyl-2 -hydroxyethyl-pheophorbide, chlorophyllide a, pheophorbide, bacteriopheophorbide, bacteriopheophytin, bacteriochlorophyllide and bacte­ riochlorophyll a in different pigment complexes. The highest relative concentrations of bacte­ riochlorophyll precursors normalized to the total amount o f bacteriochlorophyll a were found in cells during the first hour of adaptation at 0.5 μg Bchl/mg cell protein or less.

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