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1.
Mikrobiologiia ; 75(4): 562-9, 2006.
Artigo em Russo | MEDLINE | ID: mdl-17025185

RESUMO

It was shown that two stress factors, hypoxia and hyperosmotic shock, if applied simultaneously to the yeast Debaryomyces hansenii, display an antagonistic mode of interaction, which results in an increased degree of halophily of this microorganism under microaerobic conditions. Studies of the effects of respiration inhibitors (sodium azide and salicyl hydroxamic acid, SHA) and of the pattern of changes in the composition of the respiratory chain of Debaryomyces hansenii under the stated stress conditions led to the suggestion of three (or four) chains of electron transfer functioning simultaneously in the cell: the classical respiratory chain involving cytochrome-c oxidase, an alternative respiratory chain involving a cyanide- and azide-resistant oxidase, and additional respiratory chains involving oxidases resistant to salt, azide and SHA. Thus, the antagonistic mode of interaction between hypoxia and hyperosmotic shock results from the redirection of the electron flow from the salt-susceptible respiratory systems to the salt-unsusceptible ones encoded by "the hypoxia genes" and activated (induced) under microaerobic conditions.


Assuntos
Oxigênio/metabolismo , Leveduras/fisiologia , Anaerobiose , Azidas/farmacologia , Cianetos/farmacologia , Transporte de Elétrons , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Pressão Osmótica , Oxirredutases/metabolismo , Cloreto de Sódio , Leveduras/metabolismo
2.
Int J Lepr Other Mycobact Dis ; 54(2): 294-9, 1986 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-3014027

RESUMO

Factors influencing the phagocytosis of mycobacteria by 33B rat Schwannoma cells and rat peritoneal macrophages were studied. Uptake of 14C-acetate-labeled Mycobacterium w by these cells was used to set up a radiometric phagocytosis assay. Incubation at 4 degrees C and treatment with sodium azide (0.2% to 1%), colchicine (10(-7) to 10(-3) M), cytochalasin B (0.2 micrograms/ml to 25 micrograms/ml), and dibutyryl cyclic AMP (10(-7) to 10(-3) M) inhibited the phagocytosis by both cell types in a similar manner. These experiments demonstrate similarities in the mechanism of phagocytosis of mycobacteria by Schwann cells and macrophages.


Assuntos
Macrófagos/fisiologia , Mycobacterium/fisiologia , Fagocitose , Células de Schwann/fisiologia , Animais , Azidas/farmacologia , Bucladesina/farmacologia , Células Cultivadas , Colchicina/farmacologia , Temperatura Baixa , Citocalasina B/farmacologia , Neurilemoma , Fagocitose/efeitos dos fármacos , Ratos , Azida Sódica
3.
Int J Lepr Other Mycobact Dis ; 51(4): 490-4, 1983 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-6231257

RESUMO

Iron chelated to the exochelins from Mycobacterium neoaurum was taken up by a suspension of M. leprae, prepared from the liver of an infected armadillo, over 15 hr. No uptake occurred when the iron was chelated with exochelins from M. bovis BCG or M. smegmatis or to a single exochelin from M. vaccae. Uptake appeared to be by facilitated diffusion since it was not inhibited by either HgCl2, NaN3, or 2,4-dinitrophenol. This was similar to the mode of uptake of ferriexochelin into M. neoaurum itself.


Assuntos
Quelantes de Ferro/metabolismo , Ferro/metabolismo , Mycobacterium leprae/metabolismo , Peptídeos Cíclicos/metabolismo , 2,4-Dinitrofenol , Azidas/farmacologia , Transporte Biológico/efeitos dos fármacos , Difusão , Dinitrofenóis/farmacologia , Cloreto de Mercúrio , Mercúrio/farmacologia , Mycobacterium/análise , Mycobacterium bovis/análise , Peptídeos Cíclicos/isolamento & purificação , Azida Sódica
4.
J Gen Microbiol ; 128(2): 423-5, 1982 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7042905

RESUMO

Mycobacterium leprae isolated from armadillo tissue incorporated radioactivity from D-(14C)glucose and (14C)protein hydrolysate. In the presence of glucose, the rate of incorporation of (14C)protein hydrolysate was increased. Uptake of glucose was inhibited by 2-deoxy-D-glucose and sodium azide; that of the amino acids was inhibited by puromycin and chloramphenicol and, weakly, by cycloheximide.


Assuntos
Aminoácidos/metabolismo , Glucose/metabolismo , Mycobacterium leprae/metabolismo , Azidas/farmacologia , Proteínas de Bactérias/biossíntese , Transporte Biológico , Cloranfenicol/farmacologia , Cicloeximida/farmacologia , Cinética , Puromicina/farmacologia , Azida Sódica
5.
J Membr Biol ; 68(1): 67-77, 1982.
Artigo em Inglês | MEDLINE | ID: mdl-7108943

RESUMO

Microplasmodia of Physarum polycephalum have been investigated by conventional electrophysiological techniques. In standard medium (30 mM K+, 4 mM Ca++, 3 mM Mg++, 18 mM citrate buffer, pH 4.7, 22 degrees C), the transmembrane potential difference Vm is around -100 mV and the membrane resistance about 0.25 omega m2. Vm is insensitive to light and changes of the Na+/K+ ratio in the medium. Without bivalent cations in the medium and/or in presence of metabolic inhibitors (CCCP, CN-, N3-), Vm drops to about 0 mV. Under normal conditions, Vm is very sensitive to external pH (pH0), displaying an almost Nernstian slope at pH0 = 3. However, when measured during metabolic inhibition, Vm shows no sensitivity to pH0 over the range 3 to 6, only rising (about 50 mV/pH) at pH0 = 6. Addition of glucose or sucrose (but not mannitol or sorbitol) causes rapid depolarization, which partially recovers over the next few minutes. Half-maximal peak depolarization (25 mV with glucose) was achieved with 1 mM of the sugar. Sugar-induced depolarization was insensitive to pH0. The results are discussed on the basis of Class-I models of charge transport across biomembranes (Hansen, Gradmann, Sanders and Slayman, 1981, J. Membrane Biol. 63:165-190). Three transport systems are characterized: 1) An electrogenic H+ extrusion pump with a stoichiometry of 2 H+ per metabolic energy equivalent. The deprotonated form of the pump seems to be negatively charged. 2) In addition to the passive K+ pathways, there is a passive H+ transport system; here the protonated form seems to be positively charged. 3) A tentative H+-sugar cotransport system operates far from thermodynamic equilibrium, carrying negative charge in its deprotonated states.


Assuntos
Membrana Celular/fisiologia , Physarum/fisiologia , Azidas/farmacologia , Cálcio/farmacologia , Carbonil Cianeto m-Clorofenil Hidrazona/farmacologia , Membrana Celular/efeitos dos fármacos , Cianetos/farmacologia , Glucose/metabolismo , Cinética , Potenciais da Membrana/efeitos dos fármacos , Potássio/farmacologia , Sódio/farmacologia , Termodinâmica
6.
J Bacteriol ; 107(3): 787-9, 1971 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-4999415

RESUMO

Reducing agents had no effect on the oxidation of 3,4-dihydroxyphenylalanine (DOPA) to quinone by Mycobacterium leprae; no quinone formation by o-diphenoloxidase of mammalian or plant origin was detected under similar experimental conditions. Ascorbic acid and reduced glutathione prevented further oxidation and polymerization of the quinone to melanin by M. leprae; cysteine was less effective. In the presence of reducing agents, the quinone (indole-5,6-quinone) formed from DOPA by M. leprae was not reduced back to diphenol. On the other hand, the quinone (dopachrome) produced from DOPA by mammalian or plant phenolase was rapidly decolorized by reducing agents. Oxidized glutathione and cystine had little effect on o-diphenoloxidase from all of the three sources. Cyanide, which completely inhibited mammalian and plant phenolases, had only a partial effect on the enzyme in the bacilli. Various lines of evidence suggest that the properties of o-diphenoloxidase in M. leprae are different from those of similar enzymes obtained from other sources.


Assuntos
Ácido Ascórbico/farmacologia , Catecol Oxidase/metabolismo , Cisteína/farmacologia , Mycobacterium leprae/enzimologia , Animais , Azidas/farmacologia , Basidiomycota , Catecol Oxidase/antagonistas & inibidores , Sistema Livre de Células , Cianetos/farmacologia , Cistina/farmacologia , Di-Hidroxifenilalanina/metabolismo , Glutationa/farmacologia , Humanos , Manometria , Melaninas/biossíntese , Melanoma/enzimologia , Camundongos , Mycobacterium leprae/isolamento & purificação , Mycobacterium leprae/metabolismo , Oxirredução , Quinonas/biossíntese , Quinonas/metabolismo , Pele/microbiologia , Especificidade da Espécie , Espectrofotometria , Baço/microbiologia , Estereoisomerismo , Extratos de Tecidos , Tirosina/metabolismo
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