Avtor/Urednik		Čadež, Polonca; Mahne, Ivan
Naslov		Dissimilatory nitrate reductase in Pseudomonas stutzeri, Pseudomonas fluorescens, and Alcaligenes sp.
Prevedeni naslov		Disimilacijska nitratna reduktaza pri Pseudomonas stutzeri, Pseudomonas fluorescens in Alcaligenes sp.
Tip		članek
Vir		Acta Biol Slov
Vol. in št.		Letnik 42, št. 3
Leto izdaje		1999
Obseg		str. 3-15
Jezik		eng
Abstrakt		Pseudomonas stutzeri, Pseudomonas fluorescens, and Alcaligenes sp. were studied to gather more information on dissimilatory nitrate reductase, its location in the cell and molecular identity. The cells were propagated in a complex medium either with oxygen or anaerobically in the same medium containing nitrate. Cells from the logarithmic phase were fractionated into periplasmic and membrane+cytoplasmic fractions. Nitrate reductase activity in P. stutzeri was associated with the periplasmic fraction when the cells were grown under aerobic conditions. In addition, a membrane bound activity was found when the cells were propagated anaerobically on nitrate. By contrast, only membrane associated activity was evident in P. fluorescens and Alcaligenes sp., irrespective of the propagating conditions. Non-denaturing gel electrophoresis revealed nitrate reductases from both fractions of P. stutzeri in two distinct bands. In P. fluorescens and Alcaligenes sp., only one band originating from the membrane fraction of the cells grown under both aerobic and anaerobic conditions was evident. Nitrate respiration studies with intact cells under aerobic and anaerobic conditions provided evidence that only P. stutzeri was capable of aerobic nitrate reduction.
Izvleček		Pri treh denitrifikacijskih bakterijah, Pseudomonas stutzeri, Pseudomonas fluorescens in Alcaligenes sp., smo ugotavljali lokacijo nitratne reduktaze v celici in identičnost encima sintetiziranega v aerobnih oz. anaerobnih razmerah. Celice, namnožene aerobno v kompleksnem gojišču in anaerobno v enakem gojišču z dodanim nitratom, smo frakcionirali na periplazemsko in membransko+citoplazemsko frakcijo. Pri P. stutzeri smo ugotovili aktivnost nitratne reduktaze v periplazemski frakciji, če je bilo namnoževanje aerobno, v anaerobiozi pa se je pojavila dodatno še membransko vezana nitratna reduktaza. Nasprotno pa smo pri P. fluorescens in Alcaligenes sp. našli nitratno reduktazo samo v membranski frakciji ne glede na razmere namnoževanja. Nativna gelska elektroforeza je pokazala pri P. stutzeri dve aktivni lisi na različnih mestih, medtem ko se je pojavila pri P. fluorescens in Alcaligenes sp. le ena lisa, ki izvira iz membransko vezanega proteina. Pri proučevanju vpliva kisika na aktivnost nitratne reduktaze se je pokazalo, da samo pri P. stutzeri lahko poteka aerobna redukcija nitrata.
Deskriptorji		PSEUDOMONAS NITRATE REDUCTASES ALCALIGENES ELECTROPHORESIS, POLYACRYLAMIDE GEL MOLECULAR WEIGHT