Energy coupling to K+ transport in a marine bacterium

1980 ◽  
Vol 58 (10) ◽  
pp. 1206-1214 ◽  
Author(s):  
Edward G. Sedgwick ◽  
Robert A. MacLeod
Keyword(s):  
Driving Force ◽  
Maximum Rate ◽  
Marine Bacterium ◽  
Energy Coupling ◽  
Strictly Aerobic ◽  
Proton Release ◽  
Anaerobic Conditions ◽  
Intact Cells ◽  
Absorbing Material ◽  
K Transport

Cells of the marine bacterium Alteromonas haloplanktis 214 ATCC 19855 (previously referred to as marine pseudomonad B-16) were depleted of K+ by washing with 0.1 M MgSO4. Washing with 0.05 M MgSO4 lowered the Vmax for K+ transport compared with washing with 0.1 M but did not change the Km, while washing with lower concentrations of MgSO4 caused loss of ultraviolet-absorbing material from the cells. K+ uptake was a strictly aerobic process and was accompanied by proton release. When an anaerobic suspension of cells was added to incubation mixtures containing increasing amounts of O2, intracellular ATP concentrations increased as the O2 concentration increased and reached near maximum values before K+ transport began. The O2 concentration initiating K+ transport caused transport to proceed at its maximum rate. For these experiments A. haloplanktis was depleted of ATP by incubating under anaerobic conditions. Incubating with either N′,N′-dicyclohexyl carbodiimide (DCCD) or arsenate failed to deplete intact cells of ATP or prevent K+ transport. The inhibitory activity of DCCD for ATPase in membrane preparations was higher at 5 mM than at other MgSO4 concentrations and increased with time. Cyanide and the uncoupling agents tetrachlorosalicylanide (TCS) and carbonylcyanide p-trifluoromethoxyphenylhydrazone (FCCP) prevented K+ uptake while TCS and FCCP though not cyanide caused K+ to be released from K+-containing cells. It is concluded that the driving force for K+ transport in these cells is likely to be the membrane potential and that K+ transport may be gated.

The role of Na+ in membrane transport and respiration in the marine bacterium Deleya aesta 134

1991 ◽  
Vol 37 (6) ◽  
pp. 433-439 ◽  
Author(s):  
Marc Berthelet ◽  
Robert A. MacLeod
Keyword(s):  
Membrane Transport ◽  
Maximum Rate ◽  
Marine Bacterium ◽  
Transport Systems ◽  
Intact Cells ◽  
Effective Competition ◽  
Glucose Accumulation ◽  
Quinone Acceptor ◽  
The Relationship

Deleya aesta required Na+ for the uptake of 8 of 11 metabolites tested; the other three were transported at low rates in the absence of Na+ but at much higher rates in its presence. The optimal concentration of Na+ for maximum rate of transport of all the metabolites was 200 to 300 mM. Higher concentrations added as NaCl inhibited transport to the same extent as equiosomolar concentrations of other salts and sucrose. Li+ but not K+ could replace Na+ for the uptake of some metabolites but was only one-half as effective. Competition studies indicated that a number of different transport systems were involved in uptake. Inhibitor studies of succinate, L-alanine, and D-glucose accumulation (the last in both the presence and absence of Na+) suggested that for each a membrane potential was required. The relationship between rates of transport and oxidation of succinate by intact cells at various Na+ concentrations indicated that the Na+ requirement for oxidation reflected the Na+ requirement for transport. For D-glucose, the relationship was more complex, sinced over a narrow, low concentration range, Na+ inhibited respiration but not transport. Evidence for the presence in D. aesta 134 of a Na+-activated NADH–quinone acceptor oxidoreductase was obtained. Key words: Deleya aesta, marine bacteria, sodium, membrane transport, respiration.

Interaction of Gram-Negative Bacteria with the Lysosomal Fraction of Polymorphonuclear Leukocytes II. Changes in the Cell Envelope of Escherichia coli

1970 ◽  
Vol 1 (3) ◽  
pp. 311-318
Author(s):  
D. Friedberg ◽  
I. Friedberg ◽  
M. Shilo
Keyword(s):  
Escherichia Coli ◽  
Polymorphonuclear Leukocytes ◽  
Cytoplasmic Membrane ◽  
Morphological Changes ◽  
Cell Envelope ◽  
Gram Negative Bacteria ◽  
Intact Cells ◽  
Lysosomal Fraction ◽  
E Coli ◽  
Absorbing Material

Interaction of lysosomal fraction with Escherichia coli caused damage to the cell envelope of these intact cells and to the cytoplasmic membrane of E. coli spheroplasts. The damage to the cytoplasmic membrane was manifested in the release of 260-nm absorbing material and β-galactosidase from the spheroplasts, and by increased permeability of cryptic cells to O -nitrophenyl-β- d -galactopyranoside; damage to the cell wall was measured by release of alkaline phosphatase. Microscope observation showed morphological changes in the cell envelope.

Cyclobacterium halophilum sp. nov., a marine bacterium isolated from a coastal-marine wetland

2014 ◽  
Vol 64 (Pt_3) ◽  
pp. 1000-1005 ◽  
Author(s):  
Azadeh Shahinpei ◽  
Mohammad Ali Amoozegar ◽  
Abbas Akhavan Sepahy ◽  
Peter Schumann ◽  
Antonio Ventosa
Keyword(s):  
Marine Bacterium ◽  
Halophilic Bacterium ◽  
Rrna Gene ◽  
Strictly Aerobic ◽  
Content Type ◽  
Link Type ◽  
Coastal Marine ◽  
Gene Sequence Analysis ◽  
Lipid Pattern ◽  
Slightly Halophilic Bacterium

A novel Gram-stain-negative, slightly halophilic bacterium, designated strain GASx41T, was isolated from soil of the coastal–marine wetland Gomishan in Iran. Cells of strain GASx41T were curved, ring-like or horseshoe-shaped rods and non-motile. Strain GASx41T was strictly aerobic, and catalase- and oxidase-positive. The strain was able to grow at NaCl concentrations of 1–10 % (w/v), with optimum growth occurring at 2.5–3 % (w/v) NaCl. The optimum temperature and pH for growth were 25–30 °C and pH 7.5–8.0. On the basis of 16S rRNA gene sequence analysis, strain GASx41T was shown to belong to the genus Cyclobacterium within the phylum Bacteroidetes and showed closest phylogenetic similarity to ‘Cyclobacterium jeungdonense’ HMD3055 (98.0 %). The DNA G+C content of strain GASx41T was 48.1 mol%. The major cellular fatty acids of strain GASx41T were iso-C15 : 0, summed feature 4 (iso-C15 : 0 2-OH and/or C16 : 1ω7c), anteiso-C15 : 0 2-OH, anteiso-C15 : 0 and iso-C17 : 0 3-OH, and its polar lipid pattern consisted of phosphatidylethanolamine, phosphatidylcholine and 12 unknown lipids. The only quinone present was menaquinone 7 (MK-7). All these features confirmed the placement of isolate GASx41T within the genus Cyclobacterium . On the basis of evidence from this study, a novel species of the genus Cyclobacterium , Cyclobacterium halophilum sp. nov., is proposed, with strain GASx41T ( = IBRC-M 10761T = CECT 8341T) as the type strain.

scholarly journals Biotransformation of 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-Hexaazaisowurtzitane (CL-20) by Denitrifying Pseudomonas sp. Strain FA1

2003 ◽  
Vol 69 (9) ◽  
pp. 5216-5221 ◽  
Author(s):  
Bharat Bhushan ◽  
Louise Paquet ◽  
Jim C. Spain ◽  
Jalal Hawari
Keyword(s):  
Nitrous Oxide ◽  
Enzyme Preparation ◽  
Electron Transfer Reaction ◽  
Garden Soil ◽  
Resting Cells ◽  
Anaerobic Conditions ◽  
Intact Cells ◽  
Cell Biomass ◽  
Membrane Enzyme ◽  
Enzyme Catalyzed Reactions

ABSTRACT The microbial and enzymatic degradation of a new energetic compound, 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20), is not well understood. Fundamental knowledge about the mechanism of microbial degradation of CL-20 is essential to allow the prediction of its fate in the environment. In the present study, a CL-20-degrading denitrifying strain capable of utilizing CL-20 as the sole nitrogen source, Pseudomonas sp. strain FA1, was isolated from a garden soil. Studies with intact cells showed that aerobic conditions were required for bacterial growth and that anaerobic conditions enhanced CL-20 biotransformation. An enzyme(s) involved in the initial biotransformation of CL-20 was shown to be membrane associated and NADH dependent, and its expression was up-regulated about 2.2-fold in CL-20-induced cells. The rates of CL-20 biotransformation by the resting cells and the membrane-enzyme preparation were 3.2 ± 0.1 nmol h−1 mg of cell biomass−1 and 11.5 ± 0.4 nmol h−1 mg of protein−1, respectively, under anaerobic conditions. In the membrane-enzyme-catalyzed reactions, 2.3 nitrite ions (NO2 −), 1.5 molecules of nitrous oxide (N2O), and 1.7 molecules of formic acid (HCOOH) were produced per reacted CL-20 molecule. The membrane-enzyme preparation reduced nitrite to nitrous oxide under anaerobic conditions. A comparative study of native enzymes, deflavoenzymes, and a reconstituted enzyme(s) and their subsequent inhibition by diphenyliodonium revealed that biotransformation of CL-20 is catalyzed by a membrane-associated flavoenzyme. The latter catalyzed an oxygen-sensitive one-electron transfer reaction that caused initial N denitration of CL-20.

Metabolite utilization by isolated embryonic rat hearts in vitro

Development ◽  
1972 ◽  
Vol 28 (2) ◽  
pp. 235-245
Author(s):  
Steven J. Cox ◽  
David L. Gunberg
Keyword(s):  
Metabolic Pathways ◽  
Maximum Rate ◽  
Contractile Activity ◽  
Cardiac Contraction ◽  
Anaerobic Conditions ◽  
Isolated Hearts ◽  
Rat Hearts ◽  
Aerobic And Anaerobic ◽  
Aerobic And Anaerobic Conditions

Isolated hearts from 11-, 12- and 13-day rat embryos were incubated in a simple defined salt solution to which was added a variety of single substrates. Utilization of the added substrate was determined by comparing the contractile rates of the hearts in the presence and absence of the compound being tested. Of all the compounds tested only those involved in the Embden-Meyerhof glycolytic pathway were capable of maintaining cardiac contraction at a maximum rate in the 11-day heart. This was accomplished under both aerobic and anaerobic conditions. Although glycolysis remained important, the 12- and 13-day hearts exhibited a shift in dependence towards other metabolic pathways. This conclusion was based on the observations that anaerobic glycolysis could no longer maintain maximum heart rates and that a variety of non-glycolytic compounds could be utilized for contractile activity by the 12- and 13-day organs.

Na-K pump and Na-K-ATPase: disparity of their temperature sensitivity

1978 ◽  
Vol 235 (5) ◽  
pp. C159-C167 ◽  
Author(s):  
J. S. Willis ◽  
J. C. Ellory ◽  
J. H. Becker
Keyword(s):  
Temperature Sensitivity ◽  
Atp Hydrolysis ◽  
High Sensitivity ◽  
Temperature Characteristic ◽  
Ground Squirrels ◽  
Structural Reorganization ◽  
Intact Cells ◽  
Na Efflux ◽  
Resealed Ghosts ◽  
K Transport

As previously observed in red blood cells, ouabain-sensitive K influx of kidney cells grown in culture for 3 days was much less inhibited by cooling that Na-K-ATPase of the same cells. (At 5 degrees C K influx was 9.7% of that at 38 degrees C, Na-K-ATPase, 1--2%.) Resealed ghosts of erythrocytes of ground squirrels were made containing 24Na and ATP, and the Na efflux and ATP hydrolysis were measured simultaneously. Under these conditions there was no difference in the reduction of activity with cooling, and the amount of reduction was close to that of active K transport in intact cells. The high sensitivity to temperature, characteristic of broken membranes, could not be induced in intact cells or resealed ghosts by eliminating either the Na/K gradient or the ATP gradient nor by chelation of cellular and extracellular Ca. It could not be eliminated in broken membranes by protection with ATP or Mg. Structural reorganization of membrane during lysis may cause the increase in temperature sensitivity of Na-K-ATPase.

Further evidence for the existence of cyclic and non-cyclic photophosphorylation in vivo by means of desaspidin and DCMU

1967 ◽  
Vol 22 (5) ◽  
pp. 537-540 ◽  
Author(s):  
W. Urbach ◽  
W. Simonis
Keyword(s):  
Antimycin A ◽  
Anaerobic Conditions ◽  
Intact Cells ◽  
Cyclic Photophosphorylation ◽  
Aerobic And Anaerobic ◽  
Aerobic And Anaerobic Conditions

The effect of desaspidin and DCMU on photophosphorylation in intact cells under aerobic and anaerobic conditions has been studied. Desaspidin is mainly effective in N2 and inhibits under these conditions the DCMU-insensitive cyclic photophosphorylation in vivo like antimycin A. The inhibition of the phosphorylation in light by DCMU is stronger in N2 than in air which suggests a partial existence of oxydative phosphorylation during illumination.

Ouabain-sensitive liver and diaphragm respiration in cold-acclimated hamster

1977 ◽  
Vol 42 (2) ◽  
pp. 150-153 ◽  
Author(s):  
B. A. Horwitz ◽  
M. Eaton
Keyword(s):  
Transport System ◽  
Cold Exposure ◽  
Driving Force ◽  
Energy Demands ◽  
Before And After ◽  
Ouabain Inhibition ◽  
K Transport

The in vitro respiratory rates of liver and diaphragm from hamsters were compared before and after prolonged cold exposure (5 degrees C, 3–4 wk). In the presence or absence of glucose, respiratory rates were elevated in both tissues from the cold-acclimated hamsters, and these cold-induced increases were significantly reduced by ouabain. This ouabain inhibition is consistent with the hypothesis that cold exposure of these rodents stimulates the energy demands of the Na+/K+ transport system in liver and diaphragm, with these demands providing a driving force, at least in part, for respiration and accompanying cellular thermogenesis.

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