• Title/Summary/Keyword: In vivo nitrogenase

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Effect of simazine on nitrogen assimilation of rhodopseudomonas sphaeroides (Rhodopseudomonas sphaeroides의 질소 동화작용에 미치는 simazine의 영향)

  • 이혜주;이진애;박인호;선우양일
    • Korean Journal of Microbiology
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    • v.27 no.3
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    • pp.304-309
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    • 1989
  • The effects of simazine [2-chloro-4, 6-bis(methylamino)-s-triazine] on in vivo nitrogenase, glutamine synthetase, glutamate synthase, and glutamate dehydrogenase which are important in nitrogen assimilation of Rhodopseudomonas sphaeroides were investigated. Simazine inhibited the synthesis of nitrogenase and glutamine synthetase. The activity of glutamine synthetase in crude extracts of Rhodopseudomonas sphaeroides is less inhibited by simazine than that of glutamate synthase and glutamate dehydrogenase. These results suggest the possibility that simazine inhibits photosynthetic activity and so inhibits the synthesis of nitrogenase and glutamine synthetase in Rhodopseudomonas sphaeroides.

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The Relationship between Hydrogenase and Nitrogenase for Hydrogen Evolution in Rhodopseudomonas sp. KCTC 1437 (Rhodopseudomonas sp. KCTC 1437의 수소생성에 있어서의 Hydrogenase와 Nitrogenase의 관계)

  • Seol, Won-Gi;Kho, Yung-Hee
    • Microbiology and Biotechnology Letters
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    • v.14 no.5
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    • pp.385-389
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    • 1986
  • Both hydrogenase and nitrogenase were found to be involved in hydrogen evolution independently in Rhodopseudomonas sp. KCTC 1437. The hydrogen formation in this bacterium was independent on light illumination and presence of N $H_4^{+}$ After establishment of conditions to measure the amount of hydrogen evolved by each of the enzymes in vivo, the several factors affecting on the hydrogen evolution, e.g. presence of gases ( $C_2$ $H_2$, $H_2$, $O_2$ or $N_2$), C/N ratio, were investigated, Hydrogenase was less inhibited than nitrogenase under $O_2$ and was active independent on the presence of $N_2$ or $C_2$ $H_2$ which were the strong inhibitor of nitrogenase. Besides, the hydrogenase activity was increased after incubation with $H_2$. And it was verified that this bacterium consume hydrogen and photoreduce $CO_2$ by hydrogenase. From above results, it is concluded that hydrogenase in Rhodopseudomonas sp. KCTC 1437 can produce hydrogen under more favorable condition that nitrogenase.e.

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A Study on Nitrogenase - Mediated Evolution of Molecular Hydrogen in Rhodopseudomonas sphaeroides K-7 (Rhodopseudomonas sphaeroides K-7 의 질소고정 효소 의존성 수소생성에 관한 연구)

  • Lee, Jeong-Kug;Moo Bae
    • Microbiology and Biotechnology Letters
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    • v.11 no.3
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    • pp.211-216
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    • 1983
  • Rhodopseudomonas sphaeroides K-7 evolves large quantities of molecular hydrogen under anaerobic and light illuminated conditions in the presence of utilizable organic compounds as electron donors. Photoevolution of molecular hydrogen was strictly dependent on light as the activity of nitrogenase in this organism. Both of these were inhibited to the nearly same extent at varying concentrations of ammonium ion which also depressed nitrogenase synthesis. In the reaction mixtures devoid of molybdenum ion which is known as the component of nitrogenase, hydrogen evolution also decreased similarly like nitrogenase activity. Photoevolution of molecular hydrogen appeared to have no relationship with hydrogenase activity and bacteriocholophyll content and it was markedly inhibited under the atmosphere of $C_2$H$_2$, $N_2$ or $O_2$. The results strongly indicate that hydrogen evolution by R. sphaeroides K-7 might be catalyzed by nitrogenase. Both hydrogen evolution and nitrogenase activity were largely influenced by the nutritional history of the resting cells. From which we propose that glutamate might play an important role in the regulation of nigrogenase activity in vivo.

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Effect of Methionine Sulfoximine in nitrogenase activity by ammonia and glutamine in Rhodopseudomonas sphaeroides (암모니아와 glutamine에 의한 Rhodopseudomonas sphaeroides의 질소 고정 효소활성에 미치는 Methionine Sulfoximine의 영향)

  • 이혜주
    • Korean Journal of Microbiology
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    • v.26 no.3
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    • pp.215-222
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    • 1988
  • The effect of ammonia and glutamine on nitrogenase activity of Rhodopseudomonas sphaeroides was examined. The nitrogenase activity of this strain was inhibited by ammonia and glutamine. When ammonia and glutamine were exhausted, nitrogenase activity promptly resumed at its original rate. Methionine sulfoximine (MSX), irreversible glutamine synthetase (GS) inhibitor, is a structural analogue of glutamate. MSX was used in order to know whether the nitrogenase activity was inhibited by ammonia and glutamine directly or not. The ability of MSX to prevent nitrogenase switch-off by ammonia was found to be dependent upon the phase of culture. When the cells were sampled after 12 hour culture, $500{\mu}M$ MSX would not prevent the nitrogenase switch-off by ammonia. Twenty one percents of GS actibity was inhibited by $500{\mu}M$ of MSX and concentration of released ammonia decreased. But nitrogenase activiy was still inhibited by ammonia. However, nitrogenase switch-off after 20 hours would be prevented by $100{\mu}M$ of MSX. On the other hand, GS activity was ingibited completely by $100{\mu}M$ MSX and concentration of released ammonia somewhat increased. But nitrogenase activity was not inhibited. The data indicated that the inhibition of in vivo nitrogenase actibity of Rp. sphaeroides by ammonia seemed to be mediated by products of ammonia assimilation rather than by ammonia itself.

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Evolution of Molecular Hydrogen from Glucose by Rhodopseudomonas sp. KCTC 1437 (Rhodopseudomonas sp. KCTC 1437에 의한 포도당으로부터의 수소 생성)

  • Woo, Seung-Jin;Lee, Jeong-Kug;Kwon, Tae-Jong;Kho, Yung-Hee
    • Microbiology and Biotechnology Letters
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    • v.13 no.3
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    • pp.257-263
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    • 1985
  • Rhodopseudomonas sp. KCTC 1437 evolved molecular hydrogen efficiently under light illuminated anaerobic culture condition in the presence of organic acids and various sugars. especially glucose when low concentration of NH$_4$ + or L-glutamate was added to cultures. It was revealed that hydrogen formation from Rhodopseudomonas sp. KCTC 1437 was mediated by two different enzyme systems. Under the nitrogen limiting condition, hydrogen evolution from glucose was catalyzed by nitrogenase. For the nitrogenase activation in vivo, the precultured cells drown on limiting concentration of NH$_4$$^{+}$ as a sole nitrogen source showed more capacity of hydrogen evolution from glucose in the presence of L-glutamate than any other cells .frown on sufficient concentration of NH$_4$$^{+}$, L-glutamate, NH$_4$$^{+}$, or both of L-glutamate and $N_2$. A significant volume of molecular hydrogen was evolved from glucose even in the presence of excess NH$_4$$^{+}$ either in the light or dark anaerobic condition, presumably due to the mediation of hydrogen evolution by fromic hydrogenlyase.enlyase.

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