Pleiotropic Properties of Mutations to Non-alkalophily in Bacillus alcalophilus

Lewis, Richard J.; Kaback, Elizabeth; Krulwich, Terry A.

doi:10.1099/00221287-128-2-427

Cited by 5 publications

(6 citation statements)

References 4 publications

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“…The alkaliphilic bacteria which were screened for ability of bioremediation of industrial waste effluents showed that these isolates exhibited excellent growth up to a concentration of 0.2% of the industrial effluent Figure 2 indicating that these isolates can be exploited as excellent candidates for bioremediation of industrial effluents. Similar studies using alkaliphilic bacteria for bioremediation of phenol using industrial effluents have been reported [13][14][15][16][17][18].…”

Section: Screening For Bioremediation Of Industrial Waste Effluentssupporting

confidence: 67%

Bioremediation of Industrial Effluents by Alkaliphilic Bacteria Isolated from Marine Ecosystems

D¹

2018

ACT

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Alkaliphilic bacteria are a diverse group of microorganisms capable of surviving at high pH. Industrial pollutants are mainly present in industrial waste effluents which have a high pH. Therefore employing alkaliphiles for bioremediation of toxic compounds present in the industrial waste effluents would be of great help. In this study alkaliphiles were isolated from various marine ecosystems of Goa, West Coast of India. The alkaliphiles were isolated on PPYG medium (Polypeptone Yeast Extract Glucose) medium of pH 10.5.The buffering capacities of the obligate alkaliphiles obtained from the sediment and water samples were studied. These alkaliphiles were also screened for their ability to degrade a wide range of aromatic compounds and it was observed that most of the alkaliphiles utilized these aromatic compounds especially phenol as sole source of carbon. Further these obligate alkaliphiles also showed an excellent ability to grow on industrial effluents when these effluents were supplemented as sole source of carbon in MSM (Mineral Salt Medium).

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Section: Screening For Bioremediation Of Industrial Waste Effluentssupporting

confidence: 67%

Bioremediation of Industrial Effluents by Alkaliphilic Bacteria Isolated from Marine Ecosystems

D¹

2018

ACT

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“…Relevant observations include: the mutant strains do not exhibit Na+-dependent uptake of AIB, realate, aspartate, methionine or other normally Na +-coupled solutes, even at very initial time points or if monensin is added in low concentrations to replace the antiporter Guffanti et al, 1981c); the nonalkalophilic strains similarly do not exhibit Na+-dependent efflux or exchange of those solutes from unenergized vesicles--processes which would not depend upon a functional antiporter (Guffanti et al, 1981c;Bonnet et al, 1982); the nonalkalophilic mutant strains do actively transport solutes, apparently utilizing the same porters that exist in the wild type parents, but now coupling uptake via those porters to protons rather than Na § (Guffanti et al, 1981c;Bonner et al, 1982); the frequency of mutation to nonalkalophily, near one in 109 cells, is consistent with one mutationlperhaps with some restriction in site--or possibly two mutations (Lewis, Kaback & Krulwicb, 1982); the pleiotropic phenotype is found in all of the many such strains isolated, be they spontaneous mutants or mutants selected after mutagenesis, and all of the dozen or more revertants examined regain the entire wild type phenotype (Lewis et al, 1982).…”

Section: Solute Transport Is Mediated By Na § or Atp-dependent Mechanmentioning

confidence: 86%

“…The porter could be envisioned to possess the latent capacity for coupling to protons, which is only expressed upon mutational loss of the "Na + subunit." The changes in cellular cytochromes might, in this sort of model, be secondary effects resulting from the loss of Na+-dependent functions and the consequent alterations in pH~n (Lewis et al, 1982). During the years since the working hypothesis was presented, no definitive evidence has emerged, although Li + has been shown to be a substrate for the antiporter in at least some alkalophiles which cannot use Li + to replace Na + for symport (Sugiyama, Matsukura & Imae, 1985).…”

Section: Solute Transport Is Mediated By Na § or Atp-dependent Mechanmentioning

confidence: 95%

Bioenergetics of alkalophilic bacteria

Krulwich

1986

J. Membrain Biol.

101

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The central problem for organisms which grow optimally, and in some cases obligately, at pH values of 10 to 11, is the maintenance of a relatively acidified cytoplasm. A key component of the pH homeostatic mechanism is an electrogenic Na+/H+ antiporter which--by virtue of kinetic properties and/or its concentration in the membrane--catalyzes net proton uptake while the organisms extrude protons during respiration. The antiporter is also capable of maintaining a constant pHin during profound elevations in pHout as long as Na+ entry is facilitated by the presence of solutes which are taken up with Na+. Secondary to the problem of acidifying the interior is the adverse effect of the large pH gradient, acid in, on the total pmf of alkalophile cells. For the purposes of solute uptake and motility, the organisms appear to largely bypass the problem of a low pmf by utilizing a sodium motive force for energization. However, ATP synthesis appears not to resolve the energetics problem by using Na+ or by incorporating the proton-translocating ATPase into intracellular organelles. The current data suggest that effective proton pumping carried out by the alkalophile respiratory chain at high pH may deliver at least some portion of the protons to the proton-utilizing catalysts, i.e., the F1F0-ATPase and the Na+/H+ antiporter, by some localized pathway.

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“…Although the respiratory chain of non-alkalophilic strain RABN is similar to that of the wild type at pH 7.0 with respect to the relatively poor ability of NADH to cause full cytochrome reduction, the non-alkalophile grows (albeit poorly) at a neutral pH. This growth is probably facilitated by the mutational change from the Na+ coupling of solute porters to H+ coupling (2,5,8,10). The H+-coupled RABN strains can utilize the modest sum of the small pH gradient (ApH) and the small electrical gradient (At) to energize transport; the Na+- Eh (nm)…”

Section: Discussionmentioning

confidence: 99%

Respiratory chain of the alkalophilic bacterium Bacillus firmus RAB and its non-alkalophilic mutant derivative

Kitada¹,

Lewis²,

Krulwich³

1983

J Bacteriol

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The membrane-bound respiratory chain components of alkalophiic Bacillus firmus RAB were studied by difference spectroscopy and oxidation-reduction potentiometric titrations. Cytochromes with the following midpoint potentials were identified at pH 9.0: a-type cytochromes, +110 and +210 mV; b-type cytochromes, +20,-120,-280, and-400 mV; and cytochrome c, +60 mV. Only the higher-potential cytochrome a showed an upward shift in midpoint potential when titrated at pH 7.0. Parallel studies of a non-alkalophilic mutant derivative of B. firmus RAB, strain RABN, revealed the presence of only one species each of a-, band nd c-type cytochromes which exhibited midpoint potentials of +110,-150, and +160 mV, respectively, at pH 7.0. Membranes of both strains were found to contain menaquinone. At pH 9.0, NADH caused the reduction of essentially all of the cytochromes that were seen in fully reduced preparations of wild-type B. firmus RAB membranes. By contrast, at pH 7.0, NADH failed to appreciably reduce the b-type cytochromes. These findings may relate to our recent proposal that an inadequacy in energy transduction (production of a proton motive force) by the alkalophilic respiratory chain at pH 7.0 is what precludes the growth of B. firmus RAB at a neutral pH.

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Pleiotropic Properties of Mutations to Non-alkalophily in Bacillus alcalophilus

Cited by 5 publications

References 4 publications

Bioremediation of Industrial Effluents by Alkaliphilic Bacteria Isolated from Marine Ecosystems

Bioremediation of Industrial Effluents by Alkaliphilic Bacteria Isolated from Marine Ecosystems

Bioenergetics of alkalophilic bacteria

Respiratory chain of the alkalophilic bacterium Bacillus firmus RAB and its non-alkalophilic mutant derivative

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