Placement effects of organic sources on nitrogenase activity and nitrogen-fixing bacteria in flooded rice soils

1997 ◽  
Vol 25 (2) ◽  
pp. 103-108 ◽  
Author(s):  
P. K. Kanungo ◽  
B. Ramakrishnan ◽  
V. Rajaramamohan Rao
Keyword(s):  
Nitrogenase Activity ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Rice Soils ◽  
Flooded Rice

New marine nitrogen-fixing bacteria isolated from an eelgrass (Zostera marina) bed

1988 ◽  
Vol 34 (7) ◽  
pp. 886-890 ◽  
Author(s):  
Wung Yang Shieh ◽  
Usio Simidu ◽  
Yoshiharu Maruyama
Keyword(s):  
Zostera Marina ◽  
Nitrogenase Activity ◽  
Molecular Nitrogen ◽  
Exponential Growth Phase ◽  
Nitrogen Fixing ◽  
Low Oxygen ◽  
Nitrogen Fixing Bacteria ◽  
Nitrogen Fixation Activity ◽  
The Family ◽  
Ph Decrease

Four strains of marine nitrogen-fixing bacteria were isolated from the roots of eelgrass (Zostera marina) and from sediments in an eelgrass bed in Aburatsubo Inlet, Kanagawa Prefecture, Japan. Significant levels of nitrogenase activity were detected in all four strains after a few hours of incubation under anaerobic conditions. Nitrogenase activity in all cases was Na+ dependent. These strains grew anaerobically or under conditions of low oxygen, using molecular nitrogen as the sole nitrogen source. Bacterial growth in liquid nitrogen-free medium was accompanied by a marked pH decrease during the exponential growth phase. Neither yeast extract nor vitamins were required for the nitrogen fixation activity of these strains. Taxonomically, all strains were facultatively anaerobic, Gram-negative rods. They were motile in liquid medium by means of a single polar flagellum and required NaCl for their growth. These characteristics, as well as the guanine + cytosine content of their DNA (43.5 – 44.8 mol%), placed them in the family Vibrionaceae. These strains, however, could not be identified to the genus level because they were distinct from the two halophilic genera Vibrio and Photobacterium of the family Vibrionaceae by a variety of characteristics.

Research on Improvement of Nitrogenase Activity of Free-Living Nitrogen-Fixing Bacteria Using DBD Plasma

2013 ◽  
Vol 671-674 ◽  
pp. 2674-2678 ◽  
Author(s):  
Yan Yun Zhu ◽  
Xiao Li Zhu ◽  
Fang She Yang
Keyword(s):  
Rhizosphere Soil ◽  
Barrier Discharge ◽  
Nitrogenase Activity ◽  
Nitrogen Fixing ◽  
Bacterial Strains ◽  
Dbd Plasma ◽  
Nitrogen Fixing Bacteria ◽  
Free Living ◽  
Reduction Assay ◽  
Rrna Sequencing

Nitrogen-fixing bacteria were screened from the rhizosphere soil of plants in Shaanxi in China. 36 free-living nitrogen-fixing bacterial strains were isolated and their nitrogenase activity were determined by acetylene reduction assay (ARA), two strains named FLNB03 and FLNB09 with higher nitrogenase activity were isolated and identified by 16S rRNA sequencing. The datum showed that FLNB03 was similar to Acinetobacter and their similarity reached 99%, FLNB09 was similar to Agrobacterium sp. and their similarity reached 99%. Then both of them were treated using Dielectric Barrier Discharge (DBD) plasma for mutation and their mutants called FLNB03-2 and FLNB09-3 were obtained. The nitrogenase activity of FLNB03-2 was 0.61±0.10 nmol•107cfu-1•h-1, and that of FLNB09-3 was 0.40±0.05 nmol•107cfu-1•h-1, their nitrogenase activity increased by 22.00% and 14.29% than their original bacteria respectively. FLNB03-2 and FLNB09-3 might be used as microbial fertilizer.

scholarly journals Influence of ammonium and moisture on survival and nifH transcription in the diazotrophic Pseudomonas mendocina S10

2020 ◽  
Vol 12 (1) ◽  
pp. 114-123
Author(s):  
Sushma SHARMA ◽  
Dileep K. SINGH
Keyword(s):  
Nitrogenase Activity ◽  
Physiological State ◽  
Bacterial Count ◽  
Crop Productivity ◽  
Soil Conditions ◽  
Pseudomonas Mendocina ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Real Time Quantitative Pcr ◽  
Moisture Conditions

Nitrogen is important for crop productivity and usually added in form of urea into the soil which negatively affects the environment. It is important to utilize nitrogen fixing bacteria for improving the nitrogen content of soil in India. Here, we have isolated nitrogen fixing-bacteria Pseudomonas mendocina S10 from rhizospheric soil and studied its nitrogenase activity along with its survival under sterile soil conditions. Enterobacterial Repetitive Intergenic Consensus (ERIC) PCR and Real-time quantitative PCR were employed to investigate the population and nifH transcripts level respectively in presence of ammonium and moisture additives. Strain S10 was capable of growth and expressing nifH transcripts in the presence of 2.5 mM ammonium and 20 percent water availability. Population of isolated strain and it’s nifH mRNA was found at low levels when exposed to 5 mM ammonium for 60 days of incubation period. However, viable bacterial count and nifH transcript levels remained low in the presence of 1.25 mM ammonium and zero percent water content. These findings indicate that isolated strain could tolerate ammonium up to 5 mM for 60 days and can maintained their cell viability in low moisture conditions. Results revealed the advantage of using gene expression to evaluate the physiological state of microorganism’s population in soil.

scholarly journals THE INFLUENCE OF BACTERIA OF GENUS AZOSPIRILLUM ON POTENTIAL NITROGENASE ACTIVITY AND BIOSYNTETIC PROCESSES OF SPRING WHEAT AND SPRING TRITICALE

2009 ◽  
Vol 9 ◽  
pp. 138-146
Author(s):  
O.O. Shahovnina ◽  
O.V. Nadkernichna ◽  
Y.O. Vorobey ◽  
V.V. Krivopisha
Keyword(s):  
Glutamine Synthetase ◽  
Spring Wheat ◽  
Root Zone ◽  
Nitrogenase Activity ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Spring Triticale ◽  
Reliable Increase

Use of new strain of nitrogen fixing bacteria Azospirillum sp. 77 for inoculation of spring wheat and spring triticale permitted to form an effective associative system diasotroph - plant. The bacterization promoted the reliable increase of potential nitrogenase activity in root zone of plant by 38-220 %, activated the biosynthetic processes, in particular, glutamine synthetase activity increased by 57,0-71,9 %, content of protein in leaves - by 9,7-16,3 %, top of the plants - by 11,9- 18,9 %, weight of the roots - by 7,2-7,3 %.

scholarly journals BIOLOGICAL PROPERTIES OF DIAZOTROPH AZOSPIRILLUM BRASILENSE ISOLATED FROM SPRING TRITICALE ROOTS

2021 ◽  
Vol 32 ◽  
pp. 48-57
Author(s):  
О. О. Shakhovnina ◽  
O. V. Nadkernychna ◽  
V. M. Strekalov ◽  
O. P. Tymoshenko
Keyword(s):  
16S Rrna ◽  
Azospirillum Brasilense ◽  
Nitrogen Nutrition ◽  
Nitrogenase Activity ◽  
Biological Properties ◽  
Diffusion Method ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Active Strain ◽  
Spring Triticale

Objective. Study the biological properties of the diazotroph Azospirillum brasilense 10/1, promising for improving the nitrogen nutrition of spring triticale and obtaining a high quality crop. Methods. A strain of nitrogen-fixing bacteria A. brasilense 10/1 isolated from washed roots of spring triticale Oberih Kharkivskyi by accumulation cultures method using Dobreiner semi-liquid nitrogen-free medium. Nitrogen-fixing microorganisms were isolated on potato agar with succinic acid by the Dryhalsky method. Potential nitrogenase activity on washed roots of spring triticale plants and nitrogen-fixing activity of azospirilla in pure culture were measured by gas chromatography. Electron microscopic studies of bacterial cells were performed by the method of negative contrast with uranyl acetate. Identification of azospirilla was carried out on the basis of the study of morphological, cultural, physiological and biochemical characteristics and using molecular genetic methods (16S rRNA sequence analysis). The nucleotide sequences were compared with the corresponding sequences from the international database GenBank NCBI using BLAST software. The sensitivity of bacteria to antibiotics and cereal seed pesticides was tested by disk diffusion method. Results. The active strain of nitrogen-fixing bacteria, identified as Azospirillum brasilense 10/1, was obtained by analytical selection methods. The identity of the sequences of 16S rRNA of A. brasilense 10/1 with reference strains of A. brasilense in the GenBank NCBI database is 99.5 % to 99.6 %. Diazotroph A. brasilense 10/1 is sensitive to cefotaxime, norfloxacin, chloramphenicol, gentamicin, erythromycin, kanamycin, furadonin, resistant to polymyxin, ampicillin, oxacillin, amoxicillin, ciprofloxacin, ceftriaxone. Vitavax 200FF and Fundazole dressers do not affect the development of A. brasilense 10/1, Maxim Star 025 FS somewhat inhibits the development of bacteria. Conclusion. The active strain of nitrogen-fixing bacteria A. brasilense 10/1 isolated from washed roots of triticale by methods of analytical selection, is a promising inoculant to increase yields and improve grain quality of this crop. A. brasilense 10/1 is deposited in the Depository of the Institute of Microbiology and Virology of the National Academy of Sciences of Ukraine under number B- 7317 and is protected by the patent of Ukraine No. 104212.

Nitrogenase activity and nitrogen-fixing bacteria associated with root base and root tip of rice plants

1995 ◽  
Vol 150 (2) ◽  
pp. 173-177 ◽  
Author(s):  
P.K. Kanungo ◽  
G.K. Patnaik ◽  
T.K. Adhya ◽  
V. Rajaramamohan Rao
Keyword(s):  
Nitrogenase Activity ◽  
Root Tip ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Rice Plants
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