scholarly journals Inhibition of bacterial transport by uncouplers of oxidative phosphorylation. Effects of pentachlorophenol and analogues in Bacillus subtilis

1978 ◽  
Vol 176 (3) ◽  
pp. 639-647 ◽  
Author(s):  
R A Nicholas ◽  
G W Ordal
Keyword(s):  
Free Energy ◽  
Bacillus Subtilis ◽  
Oxidative Phosphorylation ◽  
Potent Inhibitor ◽  
Bacterial Transport ◽  
Specific Interactions ◽  
Acid Transport ◽  
Competitive Inhibitors ◽  
Glycine Transport ◽  
Energy Of Interaction

Analogues of the potent uncoupler of oxidative phosphorylation pentachlorophenol were tested as inhibitors of proline and glycine transport by Bacillus subtilis. These analogues included less highly substituted chlorophenols and pentachlorothiophenol. Like pentachlorophenol, they are non-competitive inhibitors of proline transport and uncompetitive inhibitors of glycine transport. However, the less highly substituted chlorophenols are weaker acids than pentachlorophenol and also weaker inhibitors. Analysis indicated that the anionic form of the uncouplers is the inhibiting species. Pentachlorothiophenol, a water-insoluble anion, is also a potent inhibitor. These results support previous studies that concluded that uncouplers of oxidative phosphorylation inhibit amino acid transport by binding at specific sites on proteins, the free energy of interaction stabilizing ‘unproductive’ conformations. Such specific interactions of uncoupler with protein are probably commonplace.

scholarly journals Use of scaled-particle theory in the assessment of the Ph4As+/Ph4B− assumption for single ions

1979 ◽  
Vol 57 (1) ◽  
pp. 71-76 ◽  
Author(s):  
Michael H. Abraham ◽  
Asadollah Nasehzadeh
Keyword(s):  
Free Energy ◽  
Recent Work ◽  
Scaled Particle Theory ◽  
Cavity Formation ◽  
Energy Term ◽  
Free Energies ◽  
Particle Theory ◽  
Novel Method ◽  
Energy Of Interaction ◽  
Solvent Molecules

A novel method for the assessment of the Ph4As+/Ph4B− assumption for free energies of transfer of single ions has recently been suggested by Treiner, and used by him to deduce that the assumption is not valid for transfers between water, propylene carbonate, sulpholane, dimethylsulphoxide, N-methyl-2-pyrrolidone, and perhaps also dimethylformamide. The basis of the method is the estimation of the free energy of cavity formation by scaled-particle theory, together with the hypothesis that the free energy of interaction of Ph4As+ (or Ph4B−) with solvent molecules is the same in all solvents, ΔGt0(int) = 0. It is shown in the present paper that (a) whether or not the Ph4As+/Ph4B− assumption applies to transfer to a given solvent depends on which other solvent is taken as the reference solvent in Treiner's method, (b) the calculation of the cavity free energy term by scaled-particle theory and by the theory of Sinanoglu – Reisse – Moura Ramos (SRMR) yields values so different that the method cannot be considered reliable, (c) the calculation of cavity enthalpies and entropies for Ph4As+ or Ph4B− by scaled-particle theory yields results that are chemically not reasonable, (d) the hypothesis that ΔGt0(int) = 0 conflicts with SRMR theory, and (e) the conclusions reached by Treiner are not in accord with recent work that in general supports the Ph4As+/Ph4B− assumption for solvents that are rejected by Treiner.

Alterations in membrane permeability with trypsin treatment

1981 ◽  
Vol 59 (8) ◽  
pp. 668-675 ◽  
Author(s):  
P. A. Johnson ◽  
R. M. Johnstone
Keyword(s):  
Amino Acid ◽  
Membrane Permeability ◽  
Amino Acid Transport ◽  
Acid Transport ◽  
Transport Activity ◽  
Trypsin Treatment ◽  
Trypsin Inhibition ◽  
Active Amino Acid ◽  
Glycine Transport ◽  
Normal Transport

Trypsin treatment of Ehrlich cells reduced sodium-coupled amino acid transport, lowered ATP levels, and abolished cation gradients. The data suggest that the decrease in active amino acid transport results from an alteration in membrane permeability caused by DNA released from a fraction of the cells upon trypsin treatment. The reduced amino acid transport appears to be the result of an abolition of ion gradients required for transport since vesicles prepared from these cells show near normal transport activity. The altered permeability of the membrane can be restored by incubation of the cells with serum. Protein synthesis does not appear to play a role in the restoration of Na+-dependent amino acid transport since restoration is unaffected by the presence of cycloheximide. The recovery of activity does depend partly on the presence of Ca2+ in the incubation medium since reversal of the trypsin inhibition of glycine transport can be obtained on incubation with Ca2+ and glucose.

scholarly journals Further studies on the substrate specificity and inhibition of the stereospecific CS2 secondary alkylsulphohydrolase of Comamonas terrigena

1980 ◽  
Vol 191 (2) ◽  
pp. 467-473 ◽  
Author(s):  
Carol H. Barrett ◽  
Kenneth S. Dodgson ◽  
Graham F. White
Keyword(s):  
Free Energy ◽  
Chain Length ◽  
Alkyl Chain ◽  
Hydrophobic Interactions ◽  
Standard Free Energy ◽  
Alkyl Chain Length ◽  
Alkyl Sulphate ◽  
Competitive Inhibitors ◽  
Free Energy Of Binding ◽  
Comamonas Terrigena

A series of d-alkan-2-yl sulphate esters (C7–C14) were prepared by sulphation of the resolved parent alcohols by a method that entails complete retention of configuration. These sulphate esters were tested as substrates for the stereospecific CS2 secondary alkylsulphohydrolase of Comamonas terrigena. Vmax. reached a maximum with the C9 compound, whereas logKm decreased linearly as the alkyl-chain length was increased from C7 to C14. A parallel series of l-alkan-2-yl sulphates was also prepared, and these esters, together with homologous series of primary alkyl sulphates and primary alkanesulphonates, were shown to be competitive inhibitors of the CS2 enzyme. For each series of compounds, logKi values decreased linearly with increasing alkyl-chain length. Plots of chain length against the standard free energy of binding (ΔG0) of substrate and inhibitors to the CS2 enzyme showed that the standard free energy of association of a –CH2– group with the enzyme was 2.0–2.4kJ/mol for all classes of compound studied, indicating an important contribution from hydrophobic interactions to the overall binding. Plots for d-alkan-2-yl sulphate substrates and primary alkyl sulphate inhibitors were nearly coincident, suggesting that the overall interaction between a primary ester and the enzyme is the same as that between the isomeric secondary substrate and the enzyme. Plots for l-alkan-2-yl sulphate and alkanesulphonate inhibitors were very similar to each other, but were displaced by 1.5–3.0kJ/mol from that for substrate binding. This indicates that the binding of any one of these particular inhibitors involves one carbon atom fewer than the number involved in binding a substrate of the same chain length. These observations are discussed in terms of a three-point attachment of substrate to the enzyme involving the alkyl chain, sulphate group and the C-1 methyl group.

scholarly journals ZpdN, a Plasmid-Encoded Sigma Factor Homolog, Induces pBS32-Dependent Cell Death in Bacillus subtilis

2016 ◽  
Vol 198 (21) ◽  
pp. 2975-2984 ◽  
Author(s):  
B.-E. Myagmarjav ◽  
M. A. Konkol ◽  
J. Ramsey ◽  
S. Mukhopadhyay ◽  
D. B. Kearns
Keyword(s):  
Cell Death ◽  
Bacillus Subtilis ◽  
Mitomycin C ◽  
Sigma Factor ◽  
Natural Transformation ◽  
Potent Inhibitor ◽  
Dna Uptake ◽  
Content Type ◽  
Dependent Cell ◽  
Necessary And Sufficient

ABSTRACTThe ancestralBacillus subtilisstrain 3610 contains an 84-kb plasmid called pBS32 that was lost during domestication of commonly used laboratory derivatives. Here we demonstrate that pBS32, normally present at 1 or 2 copies per cell, increases in copy number nearly 100-fold when cells are treated with the DNA-damaging agent mitomycin C. Mitomycin C treatment also caused cell lysis dependent on pBS32-borne prophage genes. ZpdN, a sigma factor homolog encoded by pBS32, was required for the plasmid response to DNA damage, and artificial expression of ZpdN was sufficient to induce pBS32 hyperreplication and cell death. Plasmid DNA released by cell death was protected by the capsid protein ZpbH, suggesting that the plasmid was packaged into a phagelike particle. The putative particles were further indicated by CsCl sedimentation but were not observed by electron microscopy and were incapable of killingB. subtiliscells extracellularly. We hypothesize that pBS32-mediated cell death releases a phagelike particle that is defective and unstable.IMPORTANCEProphages are phage genomes stably integrated into the host bacterium's chromosome and less frequently are maintained as extrachromosomal plasmids. Here we report that the extrachromosomal plasmid pBS32 ofBacillus subtilisencodes a prophage that, when activated, kills the host. pBS32 also encodes both the sigma factor homolog ZpdN that is necessary and sufficient for prophage induction and the protein ComI, which is a potent inhibitor of DNA uptake by natural transformation. We provide evidence that the entire pBS32 sequence may be part of the prophage and thus that competence inhibition may be linked to lysogeny.

scholarly journals Dicarboxylic acid transport in membrane vesicles from Bacillus subtilis.

1975 ◽  
Vol 124 (2) ◽  
pp. 613-622 ◽  
Author(s):  
A Bisschop ◽  
H Doddema ◽  
W N Konings
Keyword(s):  
Bacillus Subtilis ◽  
Dicarboxylic Acid ◽  
Membrane Vesicles ◽  
Acid Transport

scholarly journals The transmembrane segment of TagH is required for wall teichoic acid transport under heat stress in Bacillus subtilis

Microbiology ◽  
2018 ◽  
Vol 164 (7) ◽  
pp. 935-945 ◽  
Author(s):  
Takeshi Yamada ◽  
Mari Miyashita ◽  
Jun Kasahara ◽  
Tatsuhito Tanaka ◽  
Masayuki Hashimoto ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Heat Stress ◽  
Teichoic Acid ◽  
Acid Transport ◽  
Transmembrane Segment ◽  
Wall Teichoic Acid
Sign in / Sign up

Export Citation Format

Share Document