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L Kato

Publications and source records attributed to L Kato.

At least 37 records · Page 2Linked to original sources
PubMed1981

Energy coupling mechanisms in host-grown Mycobacterium lepraemurium.

Energy coupling mechanisms of Mycobacterium lepraemurium isolated from Sprague-Dawley rats lepromata were investigated. Cell-free extracts catalyzed phosphorylation coupled to the oxidation of generated NADH, added NADH, and succinate yielding P/O ratios of approximately 0.8, 0.6, and 0.4, respectively. Ascorbate oxidation alone or in the presence of cytochrome c or N,N,N',N'-tetramethyl-p-phenylenediamine was not coupled to ATP synthesis. The oxidative phosphorylation was completely uncoupled by 2,4-dinitrophenol, 2,6-dibromophenol, pentachlorophenol, m-chlorocarbonylcyanide phenylhydrazone, dicumarol, and gramicidin at concentrations which did not cause any inhibition of oxygen uptake. While the NADH oxidation and associated phosphate esterification was markedly sensitive to rotenone and other flavoprotein inhibitors, these inhibitors had no effect, however, on the phosphorylation coupled to succinate oxidation. The respiratory chain inhibitors such as antimycin A or 2-n-heptyl-4-hydroxyquinoline-N-oxide, and cyanide were the potent inhibitors of the phosphorylation associated with the oxidation of NADH and succinate. The ATP formation coupled to the oxidation of NADH and succinate was also inhibited by oligomycin as well as by the thiol-binding agents, p-hydroxymercuribenzoate and N-ethylmaleimide. The results indicated that NADH and succinate oxidation by in vivo grown M. lepraemurium was mediated by oxidative enzymes involving first and second energy coupling sites.

Adenosine Triphosphate↗
PubMed1980

[Oxidative phosphorylation in Mycobacterium lepraemurium].

The generation of ATP by cell-free extracts of Mycobacterium lepraemurium isolated from Sprague-Dawley rats was investigated. Cell-free preparations catalyzed phosphorylation coupled to the oxidation of NADH and succinate yielding P/O ratios of 0.6 and 0.4, respectively. Ascorbate oxidation did not result in ATP formation. The oxidative phosphorylation was uncoupled by 2,4- dinitrophenol and pentachlorophenol. Phosphate esterification coupled to NADH oxidation was inhibited by rotenone which had no effect on ATP synthesis associated with succinate oxidation. Antimycin A and cyanide completely inhibited phosphorylation coupled to the oxidation of NADH or succinate.

Adenosine Triphosphate↗
PubMed1978

Oxidation of formate by mycobacteria of the scrofulaceum group.

Intact cells obtained from Mycobacterium scrofulaceum as well as from mycobacterial strains M.A6 and M.R56 isolated respectively from leprous tissues of armadillo and rat leproma and grown with glycerol as the oxidizable substrate catalyzed complete oxidation of formate. The stoichiometry of formate oxidase system yielded a value of 2 mol of CO2 produced per mole of O2 or per 2 moles of formate consumed. Cell-free preparations from these three strains of mycobacteria contained formate dehydrogenase which was associated exclusively in the particulate fraction. Formate oxidation was markedly stimulated by small amounts of selenite and molybdate added together. Formate-reduced minus oxidized difference spectra disclosed cytochromes of the b type while spectral evidence did not suggest the existence of cytochromes a or c components. The effect of 2-N-heptyl-4-hydroxyquinoline-N-oxide on the redox state of cytochromes indicated that formate oxidation was mediated by cytochrome b with absorption maximum of 556 nm and not of 562 nm.

Aldehyde Oxidoreductases↗
PubMed1978

Mycobacterium leprae and phenoloxidase activity.

Our earlier studies indicated that the enzyme o-diphenoloxidase was absent in Mycobacterium leprae separated from depromatous human tissues. At that time the bacilli were not available from any other source. The existence or absence of this enzyme in M. leprae recovered from infected armadillo tissues were reinvestigated. The intact cells which were metabolically active, failed to oxidize DOPA. Likewise, DOPA and its derivatives were not oxidized by the enzymatically active cell-free preparations from M. leprae. Upon incubation of DOPA for more than 2 h with whole cell suspensions or particulate fractions, there was no development of colour with an absorption maximum of 540 nm as has been reported for an intermediate of DOPA oxidation. However, DOPA and several phenolic compounds were very actively oxidized by mushroom tyrosinase. The results suggested that M. leprae is deficient in o-diphenoloxidase, and this enzyme is not an intrinsic characteristic of this mycobacterium.

Animals↗
PubMed1977

Oxidation of various substrates by host grown Mycobacteria leprae and M. lepraemurium.

Oxidation of various substrates by whole cell suspensions of M. Lepraemurium and M. leprae was investigated using manometric techniques. Yeast extract, L-cysteine, dithioerythritol, and DL-penicillamine were oxidized by both M. lepraemurium as well as by M. leprae. Although tween 80 was oxidized by M. lepraemurium cell suspensions, it was not by M. leprae. Succinate was readily oxidized by whole cells of M. leprae (without being frozen) whereas it was oxidized only by M. lepraemurium cells frozen at -40 degrees C for one minute. The results indicate that M. leprae and M. lepraemurium are capable of oxidizing some substrates without requiring any cofactor and are not dependent upon host cells for respiration.

Culture Media↗
PubMed1977

Mycobacteria from leprous tissue of an armadillo cultivated on a hyaluronic acid based medium.

Mycobacteria were isolated from pooled leprous tissues of an armadillo. The suspensions of acid fast bacilli obtained were inoculated into a culture medium composed of umbilical cord extract, supplemented with yeast extract powder and glycerol with sheep serum added. Incubation temperature was 34 degrees C. An abundant growth of mycobacteria was observed in the primo culture in four weeks. The culture was easily sub-cultured on the homologous media. The primo culture did not grow on Loëwenstein medium. The identity of the cultures of mycobacteria obtained is not yet established. The same strain of mycobacteria was cultured in media inoculated with suspensions of M. leprae decontaminated with sodium hydroxide-citrate solution. We confirm the findings of Skinsnes et al. (1975) that mycobacteria from human and animal leprous tissue can be cultured repeatedly on a hyaluronic based medium.

Animals↗
PubMed1976

The respiratory metabolism of Mycobacterium lepraemurium.

The respiratory metabolism of Mycobacterium lepraemurium isolated from Sprague-Dawley rats lepromata using several substrates was investigated. None of the intermediates of the glycolysis cycle as well as of the tricarboxylic acid cycle except succinate was oxidized by purified whole suspensions of M. lepraemurium. Likewise, many sulfur compounds such as cystine, thiourea, thioacetate, thiodiglycol, mercaptoact and some sulfhydryl compounds, e.g., cysteine, dithioerythritol, dithiorthritol, and penicillamine were readily oxidized by murine bacillary suspensions, whereas thioglycolate, thioglucose, and reduced glutathione were oxidized at a slow rate. Succinate was not or was very poorly oxidized by normal cells probably because of impermeability of the cell wall but the addition of succinate to the cell suspensions frozen for 1 min at -40 degrees C considerably enhanced oxygen uptake over the endogenous value. The oxidation of succinate was unaffected by inhibitors rotenone, atabrine, and amytal but was markedly inhibited by thenoyltrifluoroacetone, antimycin A, 2-N-heptyl-4-hydroxyquinoline-N-oxide, and cyanide. The thiol-binding agents, p-hydroxymercuribenzoate and N-ethylmaleimide were also effective inhibitors of succinate oxidation but the process was not affected by uncouplers dinitrophenol, dibromophenol, pentachlorophenol, and carbonyl-cyanide-m-chlorophenylhydrazone. The results indicated that succinate oxidation by M. lepraemurium was mediated by oxidative enzymes involving an electron transport chain with oxygen as the terminal electron acceptor.

Antimycin A↗
PubMed1975

Cytochrome pigments in Mycobacterium leprae isolated from armadillos (Dasypus novemcinctus L.).

The bacilli were isolated from granulomata harvested from armadillos. Cytochrome systems in whole cell suspensions as well as in cell-free extracts were examined spectrophotometrically. The intact cells contained cytochromes of the a+b3, b and c type which were found to be present mainly in the reduced form. The cytochrome systems in cell-free extracts of M. leprae were in the oxidized form but contained the same type of cytochromes as the intact bacteria. The presence of cytochromes was easily detectable in the anaerobically-reduced (no substrate added) as well as in the dithionite- or succinate-reduced minus O2-oxidized difference spectra. The dithionite-reduced plus CO minus reduced difference spectra exhibited cytochromes a3 and o monoxide binding pigments.

Animals↗
PubMed1975

Oxidation of reduced nicotinamide adenine dinucleotide by particles from Mycobacterium lepraemurium.

Particles from Mycobacterium lepraemurium catalysed the oxidation of NADH with oxygen as the terminal electron acceptor. The preparations contained cytochromes of the a + a3'b and c types, as well as CO-binding pigments. The NADH oxidase activity was sensitive to inhibitors of the flavoprotein system as well as to HQNO and antimycin A. In addition, a cytochrome oxidase sensitive to cyanide was also present. The system was inhibited by the thiol-binding agent, PCMB, and thus indicated the involvement of sulphydryl group in the enzymatic oxidation of NADH. The sensitivity of the NADH oxidase system to all the inhibitors of the respiratory chain and the effect of these inhibitors on the absorption spectra suggested that cytochromes of the b, c, a + a3 types are involved in the transfer of electrons in NADH oxidation.

Amobarbital↗