57 Result(s)
within
Klaas J. Hellingwerf
English
-
Article
Bacteriorhodopsin in liposomes: Quantitative evaluation of ΔpH changes induced by variations of light intensity and conductivity parameters
A description of ion movement and energy transduction in terms of a kinetic variant of nonequilibrium thermodynamics was subjected to experimental tests in bacteriorhodopsin liposomes. The effects of variation...
-
Article
The role of the proton motive force and electron flow in light-driven solute transport in Rhodopseudomonas sphaeroides
-
Chapter
The Electrochemical Proton Gradient and Solute Transport in Rhodopseudo-Monas Sphaeroides
Rhodopseudomonas sphaeroides is a Gram-negative phototrophic bacterium which can grow either aerobically in the dark or anaerobically in the light. The bacteria are surrounded by a cell-envelope ...
-
Chapter
Reaction Centers from Rhodopseudomonas Sphaeroides in Reconstituted Phospholipid Vesicles. Structural Properties and Light-Dependent Proton Translocation
Reaction Centers (RC’s) from phototrophic bacteria catalyze light-driven transmembrane electron transfer as a first step in the (cyclic) electron transfer chain of such bacteria (for a review see: Okamura et a...
-
Chapter
The Lactose Carrier of Escherichia Coli Functionally Incorporated in Rhodopseudomonas Sphaeroides Obeys the Regulatory Conditions of the Phototrophic Bacterium
Regulation of solute transport in Rps. sphaeroides is such that the presence of a proton motive force by itself is not enough for solute transport to take place. In addition linear or cyclic electron transfer is ...
-
Article
The protein composition of the cytoplasmic membrane of aerobically and anaerobically grownEscherichia coli
The protein composition of the cytoplasmic membranes ofEscherichia coli, grown aerobically and anaerobically on a glucose minimal medium at pH 7.0, were analyzed by crossed immunoelectrophoresis. Qualitative diff...
-
Chapter
Light Induced Generation of a Proton Motive Force and Ca++-Transport in Membrane Vesicles of Streptococcus Cremoris Fused with Bacteriorhodopsin Proteoliposomes
The chemiosmotic hypothesis (Mitchell, 1966,1972) postulates that proton translocation by primary proton pumps generates an electrochemical proton gradient (∆p) across the cytoplasmic membrane. The electrochem...
-
Article
Reaction centers fromRhodopseudomonas sphaeroides in reconstituted phospholipid vesicles. II. Light-induced proton translocation
Unidirectional light-dependent proton translocation was demonstrated in a suspension of reconstituted reaction center (RC) vesicles supplemented with cytochromec and 2,3-dimethoxy-5-methyl-1,4-benzoquinone (UQ0),...
-
Article
Reaction centers fromRhodopseudomonas sphaeroides in reconstituted phospholipid vesicles. I. Structural studies
Reaction centers (RCs) fromRhodopseudomonas sphaeroides were reconstituted into asolectin vesicles by cosonication. Equilibrium centrifugation on sucrose gradients showed that the vesicles were homogeneous in den...
-
Chapter and Conference Paper
Functional Reconstitution of Photosynthetic Reaction Centre Complexes from Rhodopseudomonas Palustris
Reconstitution is a powerful technique in the elucidation of the mechanisms involved in membrane associated biological energy transduction (see for example Racker & Stoeckenius, 1974). For proton motive force ...
-
Chapter
Light Driven Amino Acid Uptake in Membrane Vesicles of Streptococcus Cremoris Fused with Liposomes Containing Bacterial Reaction Centers
The incorporation of primary proton pumps in biological membranes has opened attractive possibilities for studies of proton motive force (Δp)-dependent processes in isolated membrane vesicles from bacterial1, and...
-
Chapter
Carotenoid Absorbance Changes in Liposomes Reconstituted with Pigment-Protein Complexes from Rhodobacter Sphaeroides
The electrochromic behaviour of carotenoids has been widely used to determine the electrical potential difference (∆ψ) across photosynthetic membranes, like chromatophores [1] and bacterial cells [2,3]. The ca...
-
Article
Molecular cloning and functional characterization of a recA analog from Pseudomonas stutzeri and construction of a P. stutzeri recA mutant
A recombinant plasmid carrying the Pseudomonas stutzeri recA gene was isolated by complementation of the Escherichia coli recA13 mutation. Subcloning experiments showed that the gene was located on a 1500 bp PvuI...
-
Article
A Kdp-like, high-affinity, K+-translocating ATPase is expressed during growth of Rhodobacter sphaeroides in low potassium media
Cells of the purple non-sulphur bacterium Rhodobacter sphaeroides express a high-affinity K+ uptake system when grown in media with low K+ concentrations. Antibodies againts the catalytic KdpB protein or the whol...
-
Article
Regulation of the expression of thePseudomonas stutzeri recA gene
With the aid ofrecA-lacZ fusion strains, thein vivo regulation of thePseudomonas stutzeri recA gene has been studied. It is shown that expression of this gene can be induced with a variety of DNA damaging agents,...
-
Chapter
Comparison of Retinal-Based and Chlorophyll-Based Photosynthesis: A Biothermokinetic Description of Photochemical Reaction Centers
Life on earth depends on the transformation of sunlight (electromagnetic radiation) into biologically useful chemical energy. The first step in this process is the conversion of the free energy from sunlight i...
-
Article
Increased stability of recombinant plasmids by Tn1000 insertion in chemostat cultures of recombinantEscherichia coli GT123
The stability of several pBR322-derived recombinant plasmids, carrying thethr operon fromEscherichia coli, was investigated in sulfur-limited chemostat cultures ofE. coli GT123. A marked increase in the segregati...
-
Article
Physiological regulation of competence induction for natural transformation in Acinetobacter calcoaceticus
Acinetobacter calcoaceticus induced competence for natural transformation maximally after dilution of a stationary culture into fresh medium. Competence was gradually lost during prolonged exponential growth and...
-
Article
Acinetobacter calcoaceticus liberates chromosomal DNA during induction of competence by cell lysis
A transformation assay was used to assay the amount of DNA present in the extracellular medium of a growing culture of Acinetobacter calcoaceticus. It was observed that small amounts of DNA were liberated during ...
-
Article
Effect of nitrogen sources on the regulation of extracellular lipase production in Acinetobacter calcoaceticus strains
Extracellular lipase production and lipA expression were studied in A.calcoaceticus strains in relation to the nitrogen sources. Addition of casamino-acids or tryptone improved 2–3 times lipase yield as compared ...
