Characterization of a spontaneous mutant of Azotobacter vinelandii in which vanadium-dependent nitrogen fixation is not inhibited by molybdenum

Umesh K. Bageshwar; Ramesh Raina; H. K. Das

doi:10.1016/S0378-1097(98)00079-2

Characterization of a spontaneous mutant of Azotobacter vinelandii in which vanadium-dependent nitrogen fixation is not inhibited by molybdenum

Umesh K. Bageshwar, Ramesh Raina, H. K. Das

Research output: Contribution to journal › Article › peer-review

3 Scopus citations

Abstract

A spontaneous mutant derivative of Azotobacter vinelandii CA12 (ΔnifHDK), in which vanadium-dependent nitrogen fixation is not inhibited by molybdenum (A. vinelandii CARR), grows profusely on BNF-agar containing 1 μM Na₂MoO₄, alone or supplemented with 1 μM V₂O₅. The expression of A. vinelandii vnfH :: lacZ and vnfA :: lacZ fusions in A. vinelandii CARR was not inhibited by 1 mM Na₂MoO₄, whereas molybdenum at much lower concentration inhibited the expression of vnfH :: lacZ and vnfA :: lacZ fusions in A. vinelandii CA12. The mutant also exhibited normal acetylene reduction activity in the presence of 1 μM Na₂MoO₄. The expression of A. vinelandii nifH :: lacZ fusion in A. vinelandii CARR was low even though the cells were cultured under non-repressing conditions with urea as nitrogen source in the presence of Na₂MoO₄. The molybdenum content of A. vinelandii CARR cells was found to be about one-fourth that of A. vinelandii CA12. No nitrate reductase activity could be detected in A. vinelandii CARR when the cells were cultured in the presence of 10 μM Na₂MoO₄, whereas A. vinelandii CA12 exhibited some activity even with 100 pM Na₂MoO₄.

Original language	English (US)
Pages (from-to)	161-167
Number of pages	7
Journal	FEMS Microbiology Letters
Volume	162
Issue number	1
DOIs	https://doi.org/10.1016/S0378-1097(98)00079-2
State	Published - May 1 1998
Externally published	Yes

Keywords

Azotobacter vinelandii
Nitrate reductase
Vanadium-dependent nitrogen fixation
lacZ fusion

ASJC Scopus subject areas

Microbiology
Molecular Biology
Genetics

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10.1016/S0378-1097(98)00079-2

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title = "Characterization of a spontaneous mutant of Azotobacter vinelandii in which vanadium-dependent nitrogen fixation is not inhibited by molybdenum",

abstract = "A spontaneous mutant derivative of Azotobacter vinelandii CA12 (ΔnifHDK), in which vanadium-dependent nitrogen fixation is not inhibited by molybdenum (A. vinelandii CARR), grows profusely on BNF-agar containing 1 μM Na2MoO4, alone or supplemented with 1 μM V2O5. The expression of A. vinelandii vnfH :: lacZ and vnfA :: lacZ fusions in A. vinelandii CARR was not inhibited by 1 mM Na2MoO4, whereas molybdenum at much lower concentration inhibited the expression of vnfH :: lacZ and vnfA :: lacZ fusions in A. vinelandii CA12. The mutant also exhibited normal acetylene reduction activity in the presence of 1 μM Na2MoO4. The expression of A. vinelandii nifH :: lacZ fusion in A. vinelandii CARR was low even though the cells were cultured under non-repressing conditions with urea as nitrogen source in the presence of Na2MoO4. The molybdenum content of A. vinelandii CARR cells was found to be about one-fourth that of A. vinelandii CA12. No nitrate reductase activity could be detected in A. vinelandii CARR when the cells were cultured in the presence of 10 μM Na2MoO4, whereas A. vinelandii CA12 exhibited some activity even with 100 pM Na2MoO4.",

keywords = "Azotobacter vinelandii, Nitrate reductase, Vanadium-dependent nitrogen fixation, lacZ fusion",

author = "Bageshwar, {Umesh K.} and Ramesh Raina and Das, {H. K.}",

note = "Funding Information: We are grateful to Dr. P.E. Bishop for providing A. vinelandii CA12, to Dr. Suparna Taneja for the construction of pST3.2 and to Dr. V. Rajamani for his very kind help in estimation of molybdenum. Technical assistance rendered by Ms. Neeru S. Bhan is gratefully acknowledged. U.K.B. was the recipient of a fellowship from the Council of Scientific and Industrial Research, India. This study was supported by the Department of Science and Technology and the Department of Biotechnology, India.",

year = "1998",

month = may,

day = "1",

doi = "10.1016/S0378-1097(98)00079-2",

language = "English (US)",

volume = "162",

pages = "161--167",

journal = "FEMS Microbiology Letters",

issn = "0378-1097",

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TY - JOUR

T1 - Characterization of a spontaneous mutant of Azotobacter vinelandii in which vanadium-dependent nitrogen fixation is not inhibited by molybdenum

AU - Bageshwar, Umesh K.

AU - Raina, Ramesh

AU - Das, H. K.

N1 - Funding Information: We are grateful to Dr. P.E. Bishop for providing A. vinelandii CA12, to Dr. Suparna Taneja for the construction of pST3.2 and to Dr. V. Rajamani for his very kind help in estimation of molybdenum. Technical assistance rendered by Ms. Neeru S. Bhan is gratefully acknowledged. U.K.B. was the recipient of a fellowship from the Council of Scientific and Industrial Research, India. This study was supported by the Department of Science and Technology and the Department of Biotechnology, India.

PY - 1998/5/1

Y1 - 1998/5/1

N2 - A spontaneous mutant derivative of Azotobacter vinelandii CA12 (ΔnifHDK), in which vanadium-dependent nitrogen fixation is not inhibited by molybdenum (A. vinelandii CARR), grows profusely on BNF-agar containing 1 μM Na2MoO4, alone or supplemented with 1 μM V2O5. The expression of A. vinelandii vnfH :: lacZ and vnfA :: lacZ fusions in A. vinelandii CARR was not inhibited by 1 mM Na2MoO4, whereas molybdenum at much lower concentration inhibited the expression of vnfH :: lacZ and vnfA :: lacZ fusions in A. vinelandii CA12. The mutant also exhibited normal acetylene reduction activity in the presence of 1 μM Na2MoO4. The expression of A. vinelandii nifH :: lacZ fusion in A. vinelandii CARR was low even though the cells were cultured under non-repressing conditions with urea as nitrogen source in the presence of Na2MoO4. The molybdenum content of A. vinelandii CARR cells was found to be about one-fourth that of A. vinelandii CA12. No nitrate reductase activity could be detected in A. vinelandii CARR when the cells were cultured in the presence of 10 μM Na2MoO4, whereas A. vinelandii CA12 exhibited some activity even with 100 pM Na2MoO4.

AB - A spontaneous mutant derivative of Azotobacter vinelandii CA12 (ΔnifHDK), in which vanadium-dependent nitrogen fixation is not inhibited by molybdenum (A. vinelandii CARR), grows profusely on BNF-agar containing 1 μM Na2MoO4, alone or supplemented with 1 μM V2O5. The expression of A. vinelandii vnfH :: lacZ and vnfA :: lacZ fusions in A. vinelandii CARR was not inhibited by 1 mM Na2MoO4, whereas molybdenum at much lower concentration inhibited the expression of vnfH :: lacZ and vnfA :: lacZ fusions in A. vinelandii CA12. The mutant also exhibited normal acetylene reduction activity in the presence of 1 μM Na2MoO4. The expression of A. vinelandii nifH :: lacZ fusion in A. vinelandii CARR was low even though the cells were cultured under non-repressing conditions with urea as nitrogen source in the presence of Na2MoO4. The molybdenum content of A. vinelandii CARR cells was found to be about one-fourth that of A. vinelandii CA12. No nitrate reductase activity could be detected in A. vinelandii CARR when the cells were cultured in the presence of 10 μM Na2MoO4, whereas A. vinelandii CA12 exhibited some activity even with 100 pM Na2MoO4.

KW - Azotobacter vinelandii

KW - Nitrate reductase

KW - Vanadium-dependent nitrogen fixation

KW - lacZ fusion

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U2 - 10.1016/S0378-1097(98)00079-2

DO - 10.1016/S0378-1097(98)00079-2

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C2 - 9595678

AN - SCOPUS:0032080498

SN - 0378-1097

VL - 162

SP - 161

EP - 167

JO - FEMS Microbiology Letters

JF - FEMS Microbiology Letters

IS - 1

ER -

Characterization of a spontaneous mutant of Azotobacter vinelandii in which vanadium-dependent nitrogen fixation is not inhibited by molybdenum

Abstract

Keywords

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