scholarly journals Thermostability of Rhodopseudomonas viridis and Rhodospirillum rubrum chromatophores reflecting physiological conditions

2011 ◽  
Vol 1808 (6) ◽  
pp. 1645-1653 ◽  
Author(s):  
Takayuki Odahara ◽  
Noriyuki Ishii ◽  
Ayako Ooishi ◽  
Shinya Honda ◽  
Hatsuho Uedaira ◽  
...  
Keyword(s):  
Rhodospirillum Rubrum ◽  
Rhodopseudomonas Viridis ◽  
Physiological Conditions

Nachweis der Zucker in den Thylakoiden von Rhodospirillum rubrum und Rhodopseudomonas viridis

1968 ◽  
Vol 23 (5) ◽  
pp. 671-675 ◽  
Author(s):  
G. Drews
Keyword(s):  
Protein Fraction ◽  
Rhodospirillum Rubrum ◽  
Purple Bacteria ◽  
Sugar Content ◽  
Total Sugar ◽  
Water Phase ◽  
Rhodopseudomonas Viridis ◽  
Total Sugar Content ◽  
Structure Component ◽  
Phenol Water

The thylakoids (chromatophores) of the sulfur-free purple bacteria Rhodospirillum rubrum contain 30% lipids soluble in methanol-chloroform, 46% protein, and 14% carbohydrates. 90% of the total sugar content was glucose, 4% fucose, 5% rhamnose. In the thylakoids of Rhodopseudomonas viridis 3,3% sugar was demonstrable (50% glucose, 17% galactose, 15% rhamnose and 17% mannose). 2-keto-3-desoxy-octonate is a structure component in both organisms. After treatment of thylakoids with phenol/water, the main sugar fraction was in the water phase, although in both organisms 3 to 4% of the protein fraction in the phenol phase consists of sugar.

Isolation of cytochrome bc 1 complexes from the photosynthetic bacteria Rhodopseudomonas viridis and Rhodospirillum rubrum

1986 ◽  
Vol 9 (1-2) ◽  
pp. 181-195 ◽  
Author(s):  
R. Max Wynn ◽  
Dale F. Gaul ◽  
Won-Ki Choi ◽  
Robert W. Shaw ◽  
David B. Knaff
Keyword(s):  
Photosynthetic Bacteria ◽  
Rhodospirillum Rubrum ◽  
Rhodopseudomonas Viridis ◽  
Cytochrome Bc

The puh structural gene coding for the H subunit of the Rhodospirillum rubrum photoreaction center

1991 ◽  
Vol 69 (2-3) ◽  
pp. 122-131 ◽  
Author(s):  
Jacques Bérard ◽  
Gabriel Gingras
Keyword(s):  
Structural Gene ◽  
Rhodospirillum Rubrum ◽  
Rhodobacter Capsulatus ◽  
Bacterial Species ◽  
Polyacrylamide Gel Electrophoresis ◽  
Open Reading Frames ◽  
The Other ◽  
Rhodopseudomonas Viridis ◽  
Glutamic Acid Residue ◽  
Contact Points

The Rhodospirillum rubrum structural gene puh, coding for the photoreaction center H polypeptide, and three other putative genes that surround puh were cloned and sequenced. The deduced 257 amino acid H polypeptide has a molecular weight of 27 909, in close agreement with polyacrylamide gel electrophoresis determination. Hydropathy plots predict a single hydrophobic α helix. The H polypeptide of Rhodospirillum rubrum shares only 23% of its residues with all three of the H polypeptides from Rhodopseudomonas viridis, Rhodobacter capsulatus, and Rhodobacter sphaeroides. Despite this apparent low degree of similarity, statistical analysis leaves no doubt about their close relatedness. Interspecies evolutionary distance, assessed by this analysis, confirms the closeness of the two Rhodobacter species, Rhodospirillum rubrum and Rhodopseudomonas viridis being approximately equidistant from them. Three regions of the H polypeptide are highly conserved in all four species. They correspond to known contact points of H with the complex of the other two (L and M) subunits on the cytoplasmic side of the membrane. A glutamic acid residue (H polypeptide residue 177), conserved in the other bacteria and suggested to be involved in the binding of secondary quinone QB, is replaced by serine in Rhodospirillum rubrum. The open reading frames G115, I2372, and I3087 are predicted to, respectively, encode polypeptides of 480, 224, and 155 residues coiled in 10, 2, and 1 transmembrane helices. Open reading frame G115 shares 56% identical residues with F1696, a sequence similarly arranged in the genome of Rhodobacter capsulatus. The gene product of ORF 13087 is predicted to share highly similar sequences with nitrogenase reductase (encoded by nifH) of 11 different bacterial species and is suggested to have a regulatory function.Key words: gene puh, DNA sequence, codon usage, evolution.

Ultrastructure of Giant Mitochondria and Their Inclusions in Schwann Cells of Bovine Splenic Nerve

1974 ◽  
Vol 32 ◽  
pp. 194-195
Author(s):  
Å. Thureson-Klein
Keyword(s):  
Schwann Cells ◽  
Cell Organelles ◽  
Giant Mitochondria ◽  
Matrix Density ◽  
Physiological Conditions ◽  
Unmyelinated Axons ◽  
Internal Structures ◽  
Structural Abnormalities ◽  
Cytotoxic Compounds ◽  
Cell Components

Giant mitochondria of various shapes and with different internal structures and matrix density have been observed in a great number of tissues including nerves. In most instances, the presence of giant mitochondria has been associated with a known disease or with abnormal physiological conditions such as anoxia or exposure to cytotoxic compounds. In these cases degenerative changes occurred in other cell organelles and, therefore the giant mitochondria also were believed to be induced structural abnormalities.Schwann cells ensheating unmyelinated axons of bovine splenic nerve regularly contain giant mitochondria in addition to the conventional smaller type (Fig. 1). These nerves come from healthy inspected animals presumed not to have been exposed to noxious agents. As there are no drastic changes in the small mitochondria and because other cell components also appear reasonably well preserved, it is believed that the giant mitochondria are normally present jin vivo and have not formed as a post-mortem artifact.

Structural analysis of the photosynthetic membrane from Ectothiorhodospira halochloris

1983 ◽  
Vol 41 ◽  
pp. 740-741
Author(s):  
H. Engelhardt ◽  
R. Guckenberger ◽  
W. Baumeister
Keyword(s):  
Lattice Structure ◽  
Bacterial Species ◽  
Hexagonal Lattice ◽  
Reaction Centre ◽  
Photosynthetic Membrane ◽  
Rhodopseudomonas Viridis ◽  
Photosynthetic Membranes ◽  
Ectothiorhodospira Halochloris ◽  
Main Components

Bacterial photosynthetic membranes contain, apart from lipids and electron transport components, reaction centre (RC) and light harvesting (LH) polypeptides as the main components. The RC-LH complexes in Rhodopseudomonas viridis membranes are known since quite seme time to form a hexagonal lattice structure in vivo; hence this membrane attracted the particular attention of electron microscopists. Contrary to previous claims in the literature we found, however, that 2-D periodically organized photosynthetic membranes are not a unique feature of Rhodopseudomonas viridis. At least five bacterial species, all bacteriophyll b - containing, possess membranes with the RC-LH complexes regularly arrayed. All these membranes appear to have a similar lattice structure and fine-morphology. The lattice spacings of the Ectothiorhodospira haloohloris, Ectothiorhodospira abdelmalekii and Rhodopseudomonas viridis membranes are close to 13 nm, those of Thiocapsa pfennigii and Rhodopseudomonas sulfoviridis are slightly smaller (∼12.5 nm).

Freeze-fracture observations on changes in the distribution of Filipin-sterol complexes during epididymal maturation and capacitation of boar spermatozoa

1990 ◽  
Vol 48 (3) ◽  
pp. 90-91
Author(s):  
N. Seki ◽  
Y. Toyama ◽  
T. Nagano
Keyword(s):  
Plasma Membrane ◽  
Essential Role ◽  
Freeze Fracture ◽  
Final Concentration ◽  
Freeze Fracturing ◽  
Physiological Conditions ◽  
Epididymal Maturation ◽  
Cacodylate Buffer ◽  
Sperm Membrane ◽  
Boar Spermatozoa

It is believed that i ntramembra.nous sterols play an essential role in membrane stability and permeability. To investigate the distribution changes of sterols in sperm membrane during epididymal maturation and capacitation, filipin has been used as a cytochemical probe for the detection for membrane sterols. Using this technique in combination with freeze fracturing, we examined the boar spermatozoa under various physiological conditions.The spermatozoa were collected from: 1) caput, corpus and cauda epididymides, 2) sperm rich fraction of ejaculates, and 3)the uterus 2hr after natural coition. They were fixed with 2.5% glutaraldehyde in 0.05M cacodylate buffer (pH 7.4), and treated with the filipin solution (final concentration : 0.02.0.05%) for 24hr at 4°C with constant agitation. After the filipin treatment, replicas were made by conventional freeze-fracture technique. The density of filipin-sterol complexes (FSCs) was determined in the E face of the plasma membrane of head regions.

Influence of stable iodine on the uptake of the thyroid – model vs. experiment

2001 ◽  
Vol 40 (01) ◽  
pp. 31-37 ◽  
Author(s):  
U. Wellner ◽  
E. Voth ◽  
H. Schicha ◽  
K. Weber
Keyword(s):  
Time Course ◽  
Compartment Model ◽  
The Body ◽  
Iodine Uptake ◽  
Model Calculations ◽  
Physiological Conditions ◽  
Iodine Supply ◽  
Predicted Values ◽  
The Individual ◽  
Stable Iodine

Summary Aim: The influence of physiological and pharmacological amounts of iodine on the uptake of radioiodine in the thyroid was examined in a 4-compartment model. This model allows equations to be derived describing the distribution of tracer iodine as a function of time. The aim of the study was to compare the predictions of the model with experimental data. Methods: Five euthyroid persons received stable iodine (200 μg, 10 mg). 1-123-uptake into the thyroid was measured with the Nal (Tl)-detector of a body counter under physiological conditions and after application of each dose of additional iodine. Actual measurements and predicted values were compared, taking into account the individual iodine supply as estimated from the thyroid uptake under physiological conditions and data from the literature. Results: Thyroid iodine uptake decreased from 80% under physiological conditions to 50% in individuals with very low iodine supply (15 μg/d) (n = 2). The uptake calculated from the model was 36%. Iodine uptake into the thyroid did not decrease in individuals with typical iodine supply, i.e. for Cologne 65-85 μg/d (n = 3). After application of 10 mg of stable iodine, uptake into the thyroid decreased in all individuals to about 5%, in accordance with the model calculations. Conclusion: Comparison of theoretical predictions with the measured values demonstrated that the model tested is well suited for describing the time course of iodine distribution and uptake within the body. It can now be used to study aspects of iodine metabolism relevant to the pharmacological administration of iodine which cannot be investigated experimentally in humans for ethical and technical reasons.

Sign in / Sign up

Export Citation Format

Share Document