Relationship between intracellular pH and antibiotic biosynthesis in Fusidium coccineum

Shipanova, I.; Bartoshevich, Yu. E.; Sibel'dina, L A; Zaslavskaya, P. L.; Michtchenko, A.

doi:10.1007/s002530050443

Cited by 2 publications

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“…Compared with strain improvement, process control is more time-saving and direct for the fermentation process. A number of studies have been published describing the optimization of pH, temperature, DO value, as well as the regulation of agitation and aeration conditions for the overproduction of industrial products (Shioya et al, 1999;Shipanova et al, 1995;Slininger and Shea-Wilbur, 1995). Medium design strategies, on the other hand, were considered to be effective ways in metabolic control processes.…”

Section: Introductionmentioning

confidence: 99%

Optimization of the medium for streptolydigin production by Streptomyces lydicus AS 4.2501 with precursor feeding using response surface methodology

Zheng

Xian

2010

Journal of the Taiwan Institute of Chemical Engineers

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Section: Introductionmentioning

confidence: 99%

Optimization of the medium for streptolydigin production by Streptomyces lydicus AS 4.2501 with precursor feeding using response surface methodology

Zheng

Xian

2010

Journal of the Taiwan Institute of Chemical Engineers

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Intracellular pH homeostasis in the filamentous fungus Aspergillus niger

Hesse

Ruijter

Dijkema

et al. 2002

European Journal of Biochemistry

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Intracellular pH homeostasis in the filamentous fungus Aspergillus niger was measured in real time by 31 P NMR during perfusion in the NMR tube of fungal biomass immobilized in Ca 2+ -alginate beads. The fungus maintained constant cytoplasmic pH (pH cyt ) and vacuolar pH (pH vac ) values of 7.6 and 6.2, respectively, when the extracellular pH (pH ex ) was varied between 1.5 and 7.0 in the presence of citrate. Intracellular metabolism did not collapse until a DpH over the cytoplasmic membrane of 6.6-6.7 was reached (pH ex 0.7-0.8). Maintenance of these large pH differences was possible without increased respiration compared to pH ex 5.8. Perfusion in the presence of various hexoses and pentoses (pH ex 5.8) revealed that the magnitude of DpH values over the cytoplasmic and vacuolar membrane could be linked to the carbon catabolite repressing properties of the carbon source. Also, larger DpH values coincided with a higher degree of respiration and increased accumulation of polyphosphate. Addition of protonophore (carbonyl cyanide m-chlorophenylhydrazone, CCCP) to the perfusion buffer led to decreased ATP levels, increased respiration and a partial (1 lM CCCP), transient (2 lM CCCP) or permanent (10 lM CCCP) collapse of the vacuolar membrane DpH. Nonlethal levels of the metabolic inhibitor azide (N 3 -, 0.1 mM) caused a transient decrease in pH cyt that was closely paralleled by a transient vacuolar acidification. Vacuolar H + influx in response to cytoplasmic acidification, also observed during extreme medium acidification, indicates a role in pH homeostasis for this organelle. Finally, 31 P NMR spectra of citric acid producing A. niger mycelium showed that despite a combination of low pH ex (1.8) and a high acidsecreting capacity, pH cyt and pH vac values were still well maintained (pH 7.5 and 6.4, respectively).

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Relationship between intracellular pH and antibiotic biosynthesis in Fusidium coccineum

Cited by 2 publications

References 0 publications

Optimization of the medium for streptolydigin production by Streptomyces lydicus AS 4.2501 with precursor feeding using response surface methodology

Optimization of the medium for streptolydigin production by Streptomyces lydicus AS 4.2501 with precursor feeding using response surface methodology

Intracellular pH homeostasis in the filamentous fungus Aspergillus niger

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