Inhibition of Nitrogen-Fixing and Nitrifying Bacteria by Seed Plants. V. Inhibitors Produced by Bromus japonicus Thunb

1967 ◽  
Vol 12 (1) ◽  
pp. 97 ◽  
Author(s):  
Elroy L. Rice ◽  
Robert L. Parenti
Keyword(s):  
Nitrifying Bacteria ◽  
Seed Plants ◽  
Nitrogen Fixing

scholarly journals Bioremediation by Cupriavidus metallidurans Strain MSR33 of Mercury-Polluted Agricultural Soil in a Rotary Drum Bioreactor and Its Effects on Nitrogen Cycle Microorganisms

2020 ◽  
Vol 8 (12) ◽  
pp. 1952
Author(s):  
Guillermo Bravo ◽  
Paulina Vega-Celedón ◽  
Juan Carlos Gentina ◽  
Michael Seeger
Keyword(s):  
Nitrogen Cycle ◽  
Agricultural Soil ◽  
Agricultural Soils ◽  
Mercury Pollution ◽  
Nitrifying Bacteria ◽  
Innovative Technology ◽  
Soil Bioremediation ◽  
Nitrogen Fixing ◽  
Cupriavidus Metallidurans ◽  
Rotary Drum

Nitrogen cycle microorganisms are essential in agricultural soils and may be affected by mercury pollution. The aims of this study are to evaluate the bioremediation of mercury-polluted agricultural soil using Cupriavidus metallidurans MSR33 in a rotary drum bioreactor (RDB) and to characterize the effects of mercury pollution and bioremediation on nitrogen cycle microorganisms. An agricultural soil was contaminated with mercury (II) (20–30 ppm) and subjected to bioremediation using strain MSR33 in a custom-made RDB. The effects of mercury and bioremediation on nitrogen cycle microorganisms were studied by qPCR. Bioremediation in the RDB removed 82% mercury. MSR33 cell concentrations, thioglycolate, and mercury concentrations influence mercury removal. Mercury pollution strongly decreased nitrogen-fixing and nitrifying bacterial communities in agricultural soils. Notably, after soil bioremediation process nitrogen-fixing and nitrifying bacteria significantly increased. Diverse mercury-tolerant strains were isolated from the bioremediated soil. The isolates Glutamicibacter sp. SB1a, Brevundimonas sp. SB3b, and Ochrobactrum sp. SB4b possessed the merG gene associated with the plasmid pTP6, suggesting the horizontal transfer of this plasmid to native gram-positive and gram-negative bacteria. Bioremediation by strain MSR33 in an RDB is an attractive and innovative technology for the clean-up of mercury-polluted agricultural soils and the recovery of nitrogen cycle microbial communities.

scholarly journals Мікробоценози стічних вод Львова на різних етапах очищення

2013 ◽  
Vol 4 (2) ◽  
pp. 76-80
Author(s):  
K.V. Sholiak ◽  
S.О. Hnatush ◽  
T.B. Peretyatko ◽  
S.P. Gudz
Keyword(s):  
Wastewater Treatment ◽  
Treatment Plant ◽  
Selective Medium ◽  
Nitrifying Bacteria ◽  
Qualitative Composition ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Active Sludge ◽  
Resistant Strains ◽  
Reducing Bacteria

The aim of this work was to investigate some physiological groups of microorganisms which are components of wastewater microbiocenoses. Microorganisms were grown in Petri dishes containing 20–30 ml agar selective medium and in 25 ml tubes at a temperature +30 ºC. The selective media were: wort agar for microscopic fungi and yeasts, Hutchinson medium for the cellulose-destroying microorganisms, starch-ammonium medium for microorganisms that can utilize mineral nitrogen forms, Postgate B medium for sulfate-reducing bacteria, Vinogradsky medium for nitrifying bacteria, Ashby medium for the nitrogen-fixing bacteria, Chapek medium for the actinomycetes. 1 mM Cr (VI) (104 mg/l) in the form of К2Cr2О7 was added to the medium. The number of colonies was determined by the Koch method. We studied wastewater microbocenoses of Lviv city at various stages of purification. We showed that the quantitative and qualitative composition of microorganisms differed significantly in primary and secondary clarifiers, the aerotank and sludge at different stages of sewage treatment. In the initial stages of purification, in the primary sump, bacteria that reached the treatment plant with sewage were found. Nitrifying bacteria (7.1 × 106colony forming units (CFU)/ml), nitrogen-fixing bacteria (9.0 × 106CFU/ml), and fungi (3.4 × 106 CFU/ml) dominated. The qualitative composition of microorganisms in primary clarifiers and the aerotank was similar, but their number in the aerotank was significantly higher than in the primary sump: 1.5 × 107 CFU/ml of nitrifying bacteria, 1.4 × 107CFU/ml of nitrogen-fixing bacteria, 6.7 × 106CFU/ml of fungi. The ratio of different physiological groups of microorganisms in the active sludge changed significantly. The predominant microorganisms were those that assimilate mineral forms of nitrogen (65%), their number was 1.6 × 108CFU/ml. In the secondary clarifier, the largest group was cellulose-destroying microorganisms (6.0 × 105CFU/ml). However, their numbers in the secondary sump were lower compared to their numbers in the aerotank and sludge (1.5–3.9 × 106CFU/ml). Among the representatives of various physiological groups of bacteria a significant number of chromium-resistant strains was detected. The largest number of chromium-resistant strains was detected in the active sludge and aerotank, which is probably due to the recirculation of microorganisms in the wastewater treatment. The highest percentage of Cr (VI) resistant microorganisms was among sulphate-reducing bacteria. An increase in the percentage of chromium-resistant microorganisms occurred together with the lowering of the total number of microorganisms of a certain physiological group. These microorganisms could prove useful for the development of biotechnological methods wastewater treatment to eliminate chromium compounds, which are highly toxic to living organisms.

scholarly journals THE APPLICATION OF NITROGEN‐FIXING BACTERIA IN ORDER TO REDUCE THE MINERAL NITROGEN FERTILIZERS IN SUGAR BEET

Poljoprivreda ◽  
2020 ◽  
Vol 26 (2) ◽  
pp. 65-71
Author(s):  
Suzana Kristek ◽  
◽  
Sandra Brkić ◽  
Jurica Jović ◽  
Andrej Stanković ◽  
...  
Keyword(s):  
Sugar Beet ◽  
Meat Products ◽  
Vegetation Period ◽  
Mineral Nitrogen ◽  
Nitrogen Fertilizers ◽  
Nitroso Compounds ◽  
Nitrifying Bacteria ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria

The aim of this study was to examine the possibilities of reducing the mineral nitrogen fertilizers by applying the free‐living (Azotobacter chroococcum) and associative (Azospirillum brasilense) nitrifying bacteria in the sugar beet production, without a reduction in the yield and quality of the sugar beet root. Along with the vegetables, most nitrates are collected by the species of the family Chenopodiaceae, to which the sugar beet belongs. Nitrogen is one of the most vital elements in the achievement of high yields, so it is used in large quantities in fertilization. However, it is the most unstable macroelement that flushes into the deeper soil layers, and a groundwater eutrophication is caused very often. Numerous diseases are associated with the high amounts of nitrates, nitrites, and nitroso compounds, i.e., the nitrite and nitroso compounds originating from the foodstuffs having a plant origin, water, and the cured meat products. The results of the study have demonstrated that it is possible to reduce a mineral nitrogen fertilizer quantity by using the nitrogen‐fixing bacteria while even obtaining a higher quality of the studied parameters. The nitrogen‐fixing bacteria predominate in the rhizosphere, so the plants could use the amounts of nitrogen necessary in a given vegetation period, which is not the case upon a nitrogen fertilization.

ПоражениесеменныхрастенийредисагрибомAlbugocandidaприпервичномсеменоводствевМосковскойобласти

2019 ◽  
Author(s):  
A.N. Khovrin ◽  
D.A. Yanaeva
Keyword(s):  
Seed Production ◽  
Seed Plants ◽  
Albugo Candida ◽  
Generative Phase

В статье описаны симптомы поражения семенных растений редиса A. candida, дана оценка ряда сортов с разной устойчивостью к A. candida. Описаны способы борьбы с этим заболеванием при элитном семеноводстве редиса. В результате двулетней оценки образцов питомника размножения выявлено, что есть сортовая специфика устойчивости к Albugo candida. Более склонен к поражению в генеративную фазу развития сорт Кармен, наиболее устойчив к патогену сорт Меркадо.The symptoms of A. candida on seed plants radish are described a number of varieties with different resistance to A. candida are evaluated. The methods of combating of this disease in elite seed production of radish are described. As a result of twoyear evaluation of breeding nursery samples it was revealed that there is varietal specificity of resistance to A. candida. The Carmen cultivar is more prone to disease in the generative phase, the most resistant to the pathogen is Mercado cultivar.

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