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- Changes in capacities for reducing nitrate, nitrite and hydroxylaminecaused by provision or depletion of various nitrogen sourceswere investigated with a nitrogen fixing blue-green alga, Anabaenacylindrica, and adaptive nature of these reducing system wasdemonstrated.
- It was found that, under light-aerobic conditions,nitrate-and nitrite- reducing systems were induced by nitrateor nitritebut not by N2 ammonia and glutamate. On the otherhand, theactivity of enzymes pertaining to hydroxylamine reductionwasstimulated equally by nitrate, nitrite and N2. The latteractivitywas suppressed markedly in the presence of ammoniaor glutamate.
- Adaptive formation of nitrite reducing systemis completelyinhibited by chloramphenicol, a potent inhibitorof proteinsynthesis. No formation was also observed under theanaerobiccondition or in the dark.
- On the basis of thesefindings, a tentative scheme for pathwaysof nitrate reductionand nitrogen fixation in Analaena cylindricawas proposed.
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Induction of nitrate and nitrite reductases in Anabaena cylindrica(FOGG strain) was investigated. At various stages of algal growthin the presence of nitrate or nitrite, the levels of these enzymeswere determined using cell-free preparations. Nitrate and nitritereductases were induced by the respective substrates. Nitratedid not act either as an inducer or as a repressor of nitritereductase.
1This work was supported by grant No. 8814 from the Ministryof Education
2Department of Biology, Faculty of Science, Tokyo MetropolitanUniversitySetagaya-ku, Tokyo, Japan (Received June 18, 1970; ) 相似文献
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Nitrite reductase was purified about 40-fold from the blue-greenalga Anabaena cylindrica by acetone precipitation and chromatographyon DEAE-cellulose columns. The nitrite reductase had its pHoptima at about 7.6 with Tris-HCl and at about 7.4 with phosphatewhen reduced methyl viologen was used as an electron donor.The Km's for nitrite, methyl viologen and ferredoxin were 51055,2104 and 5106M, respectively. A stoichiometryof one molecule of ammonia formation per one molecule of nitritedisappearance was confirmed. Ferredoxin which had been reducedeither chemically with dithionite or enzymatically with NADPHin the presence of diaphorase was active as an electron donor.Dithionite-reduced FAD and FMN were inactive. NADPH could notgive electrons directly to nitrite reductase. Hydroxylaminereductase was segregated from nitrite reductase by DEAE-cellulosecolumn chromatography. Purified nitrite reductase showed noactivity for sulfite reduction. A molecular weight of 68,000was estimated for nitrite reductase using a calibrated SephadexG-200 column.
1This work was supported by grants 4090 and 955008 from theMinistry of Education.
2This work was supported by grants 4090 and 955008 from theMinistry of Education. 2 Present address: Department of Botany,Faculty of Science, University of Tokyo, Tokyo. 相似文献
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HYDROGENASE ACTIVITY OF CELL-FREE PREPARATION OBTAINED FROM THE BLUE-GREEN ALGA, ANABAENA CYLINDRICA
A cell-free preparation of hydrogenase was obtained from acetone-driedcells of Anabaena cylindrica. This preparation was capable ofcatalyzing the reduction of various redox dyes by molecularhydrogen and evolution of hydrogen from reduced methyl viologen.PMS, methylene blue, DPIP and toluidine blue were effective,in this order, as hydrogen acceptors. Ferricyanide, p-quinone,phenosafranine and neutral red were not reduced by the presentpreparation. PPNR obtained from this alga was effective on neitherreduction of NAD and NADP by hydrogen nor stimulation of hydrogenuptake with methylene blue and PMS. Coupled with hydrogenasereaction, there occurred reduction of nitrate to ammonia whenmethylene blue was added to the reaction mixture.
1Present address: Department of Zoology, University of Texas,Austin, Texas, U.S.A. 相似文献
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Nitrate reductase was solubilized and purified from Anabaenacylindrica by Triton X-100 treatment of particulate preparationsfollowed by adsorption on calcium phosphate gel. Reduced methylviologen, FAD or FMN, but not ferredoxin, served as an effectiveelectron donor for the nitrate reduction by solubilized nitratereductase.
1This work was supported by a grant (4061) from the Ministryof Education (Received June 25, 1970; ) 相似文献
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Kimio HIRABAYASHI Goro KIMURA Yachiyo FUKUNAGA Kumiko TSUKADA Makoto ANDO Atsushi HATTORI 《水生生物学报》2006,(6)
Adults of aquatic insects emerge fromstreamslive inthe nearby riparian zone where they can select streamsidevegetations as preferred sites in order to(a)completemetamorphosis,(b)rest while awaiting proper swarmingtime,(c)feedin order to produce eggs,or(d)mate toreproduce[1—3].Most adult aquatic insect dispersal studies have fo-cused on quantifying the degree of upstream move-ment[4,5].Some researchers have shown distinct patternsof upstreammovement related to post-mating ovipositionalbehavior[6],while there... 相似文献
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Kouhei?HATTORI Takahide A.?ISHIDA Kaori?MIKI Mayuko?SUZUKI Masahito T.?KIMURAEmail author 《Ecological Research》2004,19(3):323-329
To evaluate the responses of Quercus crispula and Quercus dentata to herbivory, their leaves were subjected to simulated herbivory in early spring and examined for the subsequent changes in leaf traits and attacks by chewing herbivores in mid summer. In Quercus crispula, nitrogen content per area was higher in artificially damaged leaves than in control leaves. This species is assumed to increase the photosynthetic rate per area by increasing nitrogen content per area to compensate leaf area loss. In Quercus dentata, nitrogen content per area did not differ between artificially damaged and control leaves, while nitrogen content per mass was slightly lower in artificially damaged leaves. The difference in their responses can be attributable to the difference in the architecture of their leaves and/or the severeness of herbivory. The development of leaf area from early spring to mid summer was larger in artificially damaged leaves than in control leaves in both species, suggesting the compensatory response to leaf area loss. Leaf dry mass per unit area was also larger in artificially damaged leaves in both species, but the adaptive significance of this change is not clear. In spite of such changes in leaf traits, no difference was detected in the degree of damage by chewing herbivores between artificially damaged and controlled leaves in both species. 相似文献
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REDUCTION OF NITRATE AND NITRITE BY SUBCELLULAR PREPARATIONS OF ANABAENA CYLINDRICA II. REDUCTION OF NITRATE TO NITRITE 总被引:1,自引:0,他引:1
Reduction of nitrate to nitrite by particulate preparationsof Anabaena cylindrica was investigated. Preparations whichshowed high activity of nitrate reductase were obtained by sonication(preparation A) or acetone treatment (preparation B). The preparationA also showed a high activity of DPIP-ascorbate photooxidation.The nitrate reductase system accepted electrons from eitherreduced ferredoxin (preparation A & B) or NADH (preparationB), but not directly from NADPH. Ferredoxin was active whenreduced either by action of photochemical system I or by NADPHand NADP-reductase, but dithionite-reduced ferredoxin was completelyinactive. Ferredoxin could be replaced with methyl viologen,benzyl viologen and diquat. Reduced FMN and FAD could serveas electron donors, but the affinity of the reductase towardthese flavin compounds was very low.
1 This work was supported by grants from the Ministry of Education(4093 and 95612) and from the National Institutes of Health,U.S. (GM-11300). 相似文献