Evidence for proton motive force dependent transport of selenite by Clostridium pasteurianum

1989 ◽  
Vol 35 (4) ◽  
pp. 481-486 ◽  
Author(s):  
Richard D. Bryant ◽  
Edward J. Laishley
Keyword(s):  
Energy Source ◽  
Proton Conductor ◽  
Anion Transport ◽  
Proton Motive Force ◽  
Motive Force ◽  
Clostridium Pasteurianum ◽  
Source Temperature ◽  
Carbonyl Cyanide ◽  
Proton Symport ◽  
Dependent Transport

The proton motive force mediated the transport of selenite [Formula: see text] in Clostridium pasteurianum cells by proton symport. The proton conductor, carbonyl cyanide m-chlorophenylhydrazone, inhibited [Formula: see text] uptake while N,N′-dicyclohexylcarbodiimide prevented [Formula: see text] uptake by presumably inhibiting the unidirectional ATPase. Acid pulse studies and antibiotic experiments with valinomycin suggest that the transmembrane ΔpH component of the proton motive force mediated the transport of [Formula: see text] into the cells. The [Formula: see text] porter system in C. pasteurianum was found to be dependent upon energy source, temperature, and medium pH.Key words: proton motive force, anion transport, selenite, Clostridium pasteurianum.

scholarly journals Extracellular gluco-oligosaccharide degradation by Caulobacter crescentus

Microbiology ◽  
2014 ◽  
Vol 160 (3) ◽  
pp. 635-645 ◽  
Author(s):  
Gerald N. Presley ◽  
Matthew J. Payea ◽  
Logan R. Hurst ◽  
Annie E. Egan ◽  
Brandon S. Martin ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Organic Molecules ◽  
Caulobacter Crescentus ◽  
Nutrient Transport ◽  
Proton Motive Force ◽  
Facilitated Diffusion ◽  
Extracellular Medium ◽  
Oligotrophic Bacterium ◽  
Carbonyl Cyanide ◽  
Dependent Transport

The oligotrophic bacterium Caulobacter crescentus has the ability to metabolize various organic molecules, including plant structural carbohydrates, as a carbon source. The nature of β-glucosidase (BGL)-mediated gluco-oligosaccharide degradation and nutrient transport across the outer membrane in C. crescentus was investigated. All gluco-oligosaccharides tested (up to celloheptose) supported growth in M2 minimal media but not cellulose or CM-cellulose. The periplasmic and outer membrane fractions showed highest BGL activity, but no significant BGL activity was observed in the cytosol or extracellular medium. Cells grown in cellobiose showed expression of specific BGLs and TonB-dependent receptors (TBDRs). Carbonyl cyanide 3-chlorophenylhydrazone lowered the rate of cell growth in cellobiose but not in glucose, indicating potential cellobiose transport into the cell by a proton motive force-dependent process, such as TBDR-dependent transport, and facilitated diffusion of glucose across the outer membrane via specific porins. These results suggest that C. crescentus acquires carbon from cellulose-derived gluco-oligosaccharides found in the environment by extracellular and periplasmic BGL activity and TBDR-mediated transport. This report on extracellular degradation of gluco-oligosaccharides and methods of nutrient acquisition by C. crescentus supports a broader suite of carbohydrate metabolic capabilities suggested by the C. crescentus genome sequence that until now have not been reported.

scholarly journals Proton motive force-dependent efflux of tetracycline in clinical isolates of Helicobacter pylori

2009 ◽  
Vol 58 (10) ◽  
pp. 1309-1313 ◽  
Author(s):  
Mona Anoushiravani ◽  
Tahereh Falsafi ◽  
Vahid Niknam
Keyword(s):  
Helicobacter Pylori ◽  
Proton Motive Force ◽  
Motive Force ◽  
Clinical Isolates ◽  
Carbonyl Cyanide ◽  
Agar Dilution ◽  
Resistant Mutants ◽  
H Pylori ◽  
High Level

The aim of this study was to evaluate the role of proton motive force (PMF)-dependent efflux in resistance of Helicobacter pylori to tetracycline (Tet). Tet MIC was determined by agar dilution in the presence and absence of carbonyl cyanide m-chlorophenylhydrazone (CCCP), an inhibitor of PMF. Antibiotic accumulation was conducted in the presence or absence of CCCP and the fluorescence of the accumulated antibiotic was measured by spectrofluorometry. In the presence of CCCP, antibiotic accumulation was increased by 2–17-fold in 17/20 Tetr isolates and by 3–10-fold in four of five high-level-resistant mutants. Correlation was observed between this increase and diminution of MIC with CCCP. PMF-dependent efflux mechanisms therefore appear to play an important role in the resistance of clinical isolates of H. pylori to Tet.

scholarly journals Effect of the proton motive force inhibitor carbonyl cyanide-m-chlorophenylhydrazone (CCCP) onPseudomonas aeruginosabiofilm development

2008 ◽  
Vol 47 (4) ◽  
pp. 298-302 ◽  
Author(s):  
A. Ikonomidis ◽  
A. Tsakris ◽  
M. Kanellopoulou ◽  
A.N. Maniatis ◽  
S. Pournaras
Keyword(s):  
Proton Motive Force ◽  
Motive Force ◽  
Carbonyl Cyanide

Role of YiaX2 in l-ascorbate transport in Klebsiella pneumoniae 13882

2009 ◽  
Vol 55 (11) ◽  
pp. 1319-1322 ◽  
Author(s):  
Evangelina Campos ◽  
Laura Aguilera ◽  
Rosa Giménez ◽  
Juan Aguilar ◽  
Laura Baldoma ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Proton Conductor ◽  
Proton Motive Force ◽  
Major Facilitator Superfamily ◽  
Aerobic Growth ◽  
Present Evidence ◽  
Carbonyl Cyanide ◽  
Ascorbate Concentration ◽  
Major Facilitator

The yiaK–S operon is required for aerobic growth on l-ascorbate in several Enterobacteriaceae. Here we present evidence that the yiaX2 gene belonging to the yiaK–S operon of Klebsiella pneumoniae 13882, which encodes a protein similar to the putative transporters classified as the major facilitator superfamily, is involved in the uptake of l-ascorbate. Concentration kinetic analysis yielded an apparent Km of YiaX2 for l-ascorbate of 161.38 ±8.28 µmol·L–1 and a Vmax of 3.81 ± 0.60 nmol·mg–1·min–1. This carrier uses the energy from electrochemical gradients, since it was inhibited by carbonyl cyanide m-chlorophenylhydrazone, a hydrophobic proton conductor that dissipates proton motive force.

scholarly journals Antibacterial Activity of Human Neutrophil Defensin HNP-1 Analogs without Cysteines

2005 ◽  
Vol 49 (11) ◽  
pp. 4561-4566 ◽  
Author(s):  
Jobin Varkey ◽  
Ramakrishnan Nagaraj
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibacterial Activity ◽  
Human Neutrophil ◽  
Therapeutic Agents ◽  
Proton Motive Force ◽  
Motive Force ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Carbonyl Cyanide

ABSTRACT The antibacterial activity of human neutrophil defensin HNP-1 analogs without cysteines has been investigated. A peptide corresponding to the HNP-1 sequence without the six cysteines (HNP-1ΔC) exhibited antibacterial activity toward gram-negative and gram-positive bacteria. Truncated analogs wherein the nine N-terminal residues of HNP-1 and the remaining three cysteines were deleted (HNP-1ΔC18) or the G was replaced with A (HNP-1ΔC18A) also exhibited antibacterial activity. Substantial activity was observed for HNP-1ΔC and HNP-1ΔC18 in the presence of 100 mM NaCl, except in the case of Pseudomonas aeruginosa. The linear peptides were active in the presence of carbonyl cyanide m-chlorophenylhydrazone (CCCP), indicating that proton motive force was not essential for killing of bacteria by the peptides. In fact, in the presence of CCCP, the peptides were active against P. aeruginosa even in the presence of 100 mM NaCl. The antibacterial activity of HNP-1ΔC, but not that of the shorter, 18-residue peptides, was attenuated in the presence of serum. The generation of defensins without cysteines would be easier than that of disulfide-linked defensins. Hence, linear defensins could have potential as therapeutic agents.

Proton motive force in a photodenitrifier, Rhodopseudomonas sphaeroides forma specialis denitrificans

1986 ◽  
Vol 64 (4) ◽  
pp. 328-336
Author(s):  
Balaram Kundu ◽  
D. J. D. Nicholas
Keyword(s):  
Electron Transport ◽  
Dark Respiration ◽  
Photosynthetic Electron Transport ◽  
Proton Motive Force ◽  
Motive Force ◽  
Antimycin A ◽  
Rhodopseudomonas Sphaeroides ◽  
Ph Values ◽  
Carbonyl Cyanide ◽  
Light Inhibition

The washed cells of Rhodopseudomonas sphaeroides f.sp. denitrificans developed a Δp of about −175 to −200 mV during denitrification in the dark and −200 to −245 mV in the light. With NO2− as the terminal acceptor, Δp was less than with NO3−, N2O, or O2. The values of Δψ in the dark were about −150 mV for NO3− and N2O and −140 mV for NO2−. During photodenitrification with NO3−, NO2−, or N2O or respiration to O2 in light, Δψ ranged between −152 and −167 mV. Like Δψ, the ΔpH was higher in light than in the dark, resulting in a 20- to 30-mV increase in Δp during illumination with NO3−, NO2−, or N2O as the acceptor. Both ΔpH and Δψ were reduced at higher pH values (≥ 7.5). Changes in pH in response to O2 in the light were less than those in the dark, indicating light inhibition of O2 respiration. The cells maintained a reasonably high Δp without addition of a substrate or when inhibitors were used; the cells retained a fairly high Δψ even in the presence of an inhibitor. However, ΔpH was appreciably lowered and in some cases it was almost abolished when either KCN, rotenone, NaN3, carbonyl cyanide m-chlorophenylhydrazone (CCCP), 2,4-dinitrophenol, N,N′-dicyclohexylcarbodiimide, antimycin A, or 2-n-heptyl-4-hydroxyquinoline-N-oxide (HOQNO) was used. The combination of an uncoupler (e.g., CCCP) and an electron transport effector (e.g., antimycin A) further reduced the ΔpH. Antimycin A and HOQNO were more effective in inhibiting photosynthetic electron transport to NO3−, NO2−, N2O, or O2 than the dark respiration to these substrates. Dibromomethylisopropyl-p-benzoquinone, a quinone antagonist, markedly reduced ΔpH in light with NO3−, NO2−, N2O, or O2 as the terminal acceptor, indicating that photosynthetically generated electrons are used for denitrification in this bacterium.

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