scholarly journals Effect of Nitrogen Source on Growth and Trichloroethylene Degradation by Methane-Oxidizing Bacteria

1998 ◽  
Vol 64 (9) ◽  
pp. 3451-3457 ◽  
Author(s):  
Kung-Hui Chu ◽  
Lisa Alvarez-Cohen
Keyword(s):  
Nitrogen Source ◽  
Chemostat Culture ◽  
Molecular Nitrogen ◽  
Nitrogen Sources ◽  
Cellular Growth ◽  
Nitrogen Fixing ◽  
External Energy ◽  
Oxidation Rates ◽  
Methane Oxidizing Bacteria ◽  
Tce Degradation

ABSTRACT The effect of nitrogen source on methane-oxidizing bacteria with respect to cellular growth and trichloroethylene (TCE) degradation ability were examined. One mixed chemostat culture and two pure type II methane-oxidizing strains, Methylosinus trichosporium OB3b and strain CAC-2, which was isolated from the chemostat culture, were used in this study. All cultures were able to grow with each of three different nitrogen sources: ammonia, nitrate, and molecular nitrogen. Both M. trichosporium OB3b and strain CAC-2 showed slightly lower net cellular growth rates and cell yields but exhibited higher methane uptake rates, levels of poly-β-hydroxybutyrate (PHB) production, and naphthalene oxidation rates when grown under nitrogen-fixing conditions. The TCE-degrading ability of each culture was measured in terms of initial TCE oxidation rates and TCE transformation capacities (mass of TCE degraded/biomass inactivated), measured both with and without external energy sources. Higher initial TCE oxidation rates and TCE transformation capacities were observed in nitrogen-fixing mixed, M. trichosporium OB3b, and CAC-2 cultures than in nitrate- or ammonia-supplied cells. TCE transformation capacities were found to correlate with cellular PHB content in all three cultures. The results of this study suggest that the nitrogen-fixing capabilities of methane-oxidizing bacteria can be used to select for high-activity TCE degraders for the enhancement of bioremediation in fixed-nitrogen-limited environments.

Nitrogen Fixation and the Utilization of Other Inorganic Nitrogen Sources in a Subarctic Lake

1968 ◽  
Vol 25 (10) ◽  
pp. 2101-2110 ◽  
Author(s):  
Vera A. Billaud
Keyword(s):  
Nitrogen Source ◽  
Nitrate Uptake ◽  
Inorganic Nitrogen ◽  
Molecular Nitrogen ◽  
Nitrogen Sources ◽  
Lake Surface ◽  
Interior Alaska ◽  
Uptake Rates ◽  
Tracer Methods ◽  
Subarctic Lake

A year-round limnological study of the biological utilization of molecular nitrogen, ammonia, and nitrate in Smith Lake, a small subarctic lake in interior Alaska, showed that ammonia was consistently the most important nitrogen source. Of the two main algal production periods, the first took place under the ice in May, and depended on ammonia accumulated during the winter for a nitrogen source. The population at this time consisted largely of microflagellates. Chlamydomonas, Euglena, Chlorella, and Mellamonas were among the identified algae present. Immediately after the ice melted from the lake surface, a second population developed. These algae, consisting almost exclusively of Anabaena flos-aquae, used ammonia, nitrate, and molecular nitrogen simultaneously. During the remainder of the summer, uptake rates remained relatively low, with ammonia the most important nitrogen source; during the fall, nitrate uptake briefly approached the magnitude of ammonia uptake. 15N tracer methods were used to measure the uptake rates in this work.

scholarly journals Nitrogen Metabolism of an Anoxygenic Filamentous Phototrophic Bacterium Oscillocholris trichoides Strain DG-6

Microbiology ◽  
2021 ◽  
Vol 90 (4) ◽  
pp. 428-434
Author(s):  
R. N. Ivanovsky ◽  
N. V. Lebedeva ◽  
O. I. Keppen ◽  
T. P. Tourova
Keyword(s):  
Glutamine Synthetase ◽  
Nitrogen Source ◽  
Glutamate Dehydrogenase ◽  
Molecular Nitrogen ◽  
Single Gene ◽  
Nitrogen Sources ◽  
Entire Family ◽  
Ammonium N ◽  
Expression Product ◽  
Typical Strain

Abstract— The possible nitrogen sources for Osc. trichoides DG6, a typical strain of the Oscillochloridaceae family, are ammonium, N2, glutamate, asparagine, glycine, and glutamine. The assimilation of molecular nitrogen occurs with the participation of nitrogenase, the structural gene of which, nifH, is located in the gene cluster which also includes the genes of the nifD and nifK nitrogenase subunits and the auxiliary nifB gene. Considering that nifHBDK clusters have been also annotated in the genomes of other members of the Oscillochloridaceae family, including uncultured and candidate taxa, it can be assumed that the ability to fix nitrogen is a property immanent for this entire family. The pathways for assimilating ammonium in the cells grown using different nitrogen sources may differ. Osc. trichoides DG6 growing in a medium containing ammonium assimilated it with the participation of glutamate dehydrogenase, which is determined by a single gene. The expression product of this gene has dual functionality and can be used to implement the reaction with both NAD and NADP. With the growth of Osc. trichoides DG6 on a medium with glutamate as the only nitrogen source all the enzymes necessary for the implementation of the GS‑GOGAT pathway were found in the cells. However, for the glutamine synthetase reaction, ammonium, which was absent in the growth medium, was required. The source of ammonium may be glutamate metabolized through glutamate dehydrogenase.

scholarly journals Effects of nitrogen and carbon sources on the production of inulinase from strain Bacillus sp. SG113

2016 ◽  
Vol 3 (1) ◽  
pp. 69-74
Author(s):  
Simeon Gavrailov ◽  
Viara Ivanova
Keyword(s):  
Nitrogen Source ◽  
Organic Nitrogen ◽  
Inorganic Nitrogen ◽  
Carbon Sources ◽  
Casein Hydrolysate ◽  
Jerusalem Artichoke ◽  
Nitrogen Sources ◽  
Cellular Growth ◽  
Bacillus Sp ◽  
Carbon And Nitrogen

Abstract The effects of the carbon and nitrogen substrates on the growth of Bacillus sp. SG113 strain were studied. The use of organic nitrogen sources (peptone, beef extract, yeast extract, casein) leads to rapid cellular growth and the best results for the Bacillus strain were obtained with casein hydrolysate. From the inorganic nitrogen sources studied, the (NH4) 2SO4 proved to be the best nitrogen source. Casein hydrolysate and (NH4) 2SO4 stimulated the invertase synthesis. In the presence of Jerusalem artichoke, onion and garlic extracts as carbon sources the strain synthesized from 6 to 10 times more inulinase.

scholarly journals Evaluation of Toxic Effects of Aeration and Trichloroethylene Oxidation on Methanotrophic Bacteria Grown with Different Nitrogen Sources

1999 ◽  
Vol 65 (2) ◽  
pp. 766-772 ◽  
Author(s):  
Kung-Hui Chu ◽  
Lisa Alvarez-Cohen
Keyword(s):  
Respiratory Activity ◽  
Molecular Nitrogen ◽  
Nitrogen Sources ◽  
Viable Cell ◽  
Toxic Effects ◽  
Cellular Damage ◽  
Methanotrophic Bacteria ◽  
Oxidation Rates ◽  
Formate Oxidation ◽  
Soluble Methane Monooxygenase

ABSTRACT In this study we evaluated specific and nonspecific toxic effects of aeration and trichloroethylene (TCE) oxidation on methanotrophic bacteria grown with different nitrogen sources (nitrate, ammonia, and molecular nitrogen). The specific toxic effects, exerted directly on soluble methane monooxygenase (sMMO), were evaluated by comparing changes in methane uptake rates and naphthalene oxidation rates following aeration and/or TCE oxidation. Nonspecific toxic effects, defined as general cellular damage, were examined by using a combination of epifluorescent cellular stains to measure viable cell numbers based on respiratory activity and measuring formate oxidation activities following aeration and TCE transformation. Our results suggest that aeration damages predominantly sMMO rather than other general cellular components, whereas TCE oxidation exerts a broad range of toxic effects that damage both specific and nonspecific cellular functions. TCE oxidation caused sMMO-catalyzed activity and respiratory activity to decrease linearly with the amount of substrate degraded. Severe TCE oxidation toxicity resulted in total cessation of the methane, naphthalene, and formate oxidation activities and a 95% decrease in the respiratory activity of methanotrophs. The failure of cells to recover even after 7 days of incubation with methane suggests that cellular recovery following severe TCE product toxicity is not always possible. Our evidence suggests that generation of greater amounts of sMMO per cell due to nitrogen fixation may be responsible for enhanced TCE oxidation activities of nitrogen-fixing methanotrophs rather than enzymatic protection mechanisms associated with the nitrogenase enzymes.

scholarly journals Effects of Nitrogen and Carbon Sources on Transcription of Soluble Methyltransferases in Methanosarcina mazei Strain Gö1

2005 ◽  
Vol 187 (17) ◽  
pp. 6147-6154 ◽  
Author(s):  
Katharina Veit ◽  
Claudia Ehlers ◽  
Ruth A. Schmitz
Keyword(s):  
Nitrogen Source ◽  
Degradation Products ◽  
Molecular Nitrogen ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Initial Step ◽  
Conclusive Evidence ◽  
Carbon And Nitrogen ◽  
Methanosarcina Mazei ◽  
Or Genes

ABSTRACT The methanogenic archaeon Methanosarcina mazei strain Gö1 uses versatile carbon sources and is able to fix molecular nitrogen with methanol as carbon and energy sources. Here, we demonstrate that when growing on trimethylamine (TMA), nitrogen fixation does not occur, indicating that ammonium released during TMA degradation is sufficient to serve as a nitrogen source and represses nif gene induction. We further report on the transcriptional regulation of soluble methyltransferases, which catalyze the initial step of methylamine consumption by methanogenesis, in response to different carbon and nitrogen sources. Unexpectedly, we obtained conclusive evidence that transcription of the mtmB2C2 operon, encoding a monomethylamine (MMA) methyltransferase and its corresponding corrinoid protein, is highly increased under nitrogen limitation when methanol serves as a carbon source. In contrast, transcription of the homologous mtmB1C1 operon is not affected by the nitrogen source but appears to be increased when TMA is the sole carbon and energy source. In general, transcription of operons encoding dimethylamine (DMA) and TMA methyltransferases and methylcobalamine:coenzyme M methyltransferases is not regulated in response to the nitrogen source. However, in all cases transcription of one of the homologous operons or genes is increased by TMA or its degradation products DMA and MMA.

Hydroxylamines as One-Atom Nitrogen Sources for Metal-Catalyzed Cycloadditions

Synthesis ◽  
2021 ◽  
Author(s):  
Xinjun Luan ◽  
Jingxun Yu
Keyword(s):  
Transition Metal ◽  
Nitrogen Source ◽  
Nucleophilic Reagent ◽  
Nitrogen Sources ◽  
Short Review ◽  
Indole Derivatives ◽  
Electrophilic Amination ◽  
Intramolecular Cycloaddition ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

AbstractTransition-metal-catalyzed C–N bond formation is one of the most important pathways to synthesize N-heterocycles. Hydroxylamines can be transformed into a nucleophilic reagent to react with a carbon cation or coordinate with a transition metal; it can also become an electrophilic nitrogen source to react with arenes, alkenes, and alkynes. In this short review, the progress made on transition-metal-catalyzed cycloadditions with hydroxylamines as a nitrogen source is summarized.1 Introduction2 Cycloaddition To Form Aziridine Derivatives2.1 Intramolecular Cycloaddition To Form Aziridine Derivatives2.2 Intermolecular Cycloaddition To Form Aziridine Derivatives3 Cycloaddition To Form Indole Derivatives4 Cycloaddition To Form Other N-Heterocycles4.1 Aza-Heck-Type Amination Reactions4.2 Nitrene Insertion Amination Reactions4.3 Intramolecular Nucleophilic and Electrophilic Amination Reactions5 Conclusion and Outlook

scholarly journals Studies on the Role of the are a Gene in the Regulation of Nitrogen Catabolism in Aspergillus nidulans

1975 ◽  
Vol 28 (3) ◽  
pp. 301 ◽  
Author(s):  
MJ Hynes
Keyword(s):  
Nitrogen Source ◽  
Aspergillus Nidulans ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Selection Methods ◽  
Growth Responses ◽  
Dominance Relationships ◽  
Regulatory Circuits ◽  
Specific Activities

Mutants of Apergillus nidulanswith lesions in a gene, areA (formerly called amdT), have been isolated by a variety of different selection methods. The areA mutants show a range of pleiotropic growth responses to a number of compounds as sole nitrogen sources, but are normal in utilization of carbon sources. The levels of two amidase enzymes as well as urease have been investigated in the mutants and have been shown to be affected by this gene. Most of the areA mutants have much lower amidase-specific activities when grown in ammonium-containing medium, compared with mycelium incubated in medium la9king a nitrogen source. Some of the areA. mutants do not show derepression of urease upon relief of ammonium repression. The dominance relationships of areA alleles have been investigated in� heterozygous diploids, and these studies lend support to the proposal that areA codes for a positively acting regulatory product. One of the new areA alleles is partially dominant to areA + and areA102. This may be a result of negative complementation or indicate that areA has an additional negative reiuIatory function. Investigation.of various amdR; areA double mutants has led to the conclusion that amdR and areA participate in independent regulatory circuits in the control of acetamide utilizatiol1. Studies on an amdRc; areA.double mutant indicate that areA is involved in derepression of acetamidase upon relief of ammo.nium repression.

scholarly journals Varied Diazotrophies, Morphologies, and Toxicities of Genetically Similar Isolates of Cylindrospermopsis raciborskii(Nostocales, Cyanophyceae) from Northern Australia

2001 ◽  
Vol 67 (4) ◽  
pp. 1839-1845 ◽  
Author(s):  
Martin L. Saker ◽  
Brett A. Neilan
Keyword(s):  
Nitrogen Source ◽  
Growth Rates ◽  
Vegetative Cell ◽  
Nitrogen Sources ◽  
Water Bodies ◽  
Cylindrospermopsis Raciborskii ◽  
Rrna Gene ◽  
Northern Australia ◽  
Fixed Nitrogen ◽  
Freeze Dried

ABSTRACT The potentially toxic freshwater cyanobacteriumCylindrospermopsis raciborskii has become increasingly prevalent in tropical and temperate water bodies worldwide. This paper investigates the effects of different nitrogen sources (NO3 −, NH4 +, and omission of a fixed form of nitrogen) on the growth rates, morphologies, and cylindrospermopsin (CYL) concentrations (expressed as a percentage of the freeze-dried weight) of seven C. raciborskii isolates obtained from a range of water bodies in northern Australia and grown in batch culture. In general, growth rates were lowest in the absence of a fixed-nitrogen source and highest with NH4 + as the nitrogen source. Conversely, the highest concentrations of CYL were recorded in cultures grown in the absence of a fixed-nitrogen source and the lowest were found in cultures supplied with NH4 +. Cultures supplied with NO3 − were intermediate with respect to both CYL concentration and growth rate. Different nitrogen sources resulted in significant differences in the morphology of C. raciborskii trichomes. Most notable were the loss of heterocysts and the tapering of end cells in cultures supplied with NH4 + and the statistically significant increase in vegetative cell length (nitrogen depleted < NO3 − < NH4 +). The morphological changes induced by different nitrogen sources were consistent for all isolates, despite measurable differences in vegetative-cell and heterocyst dimensions among isolates. Such induced morphological variation has implications forCylindrospermopsis taxonomy, given that distinctions between species are based on minor and overlapping differences in cell lengths and widths. The close phylogenetic association among all seven isolates was confirmed by the high level (>99.8%) of similarity of their 16S rRNA gene sequences. Another genetic technique, analysis of the HIP1 octameric-palindrome repeated sequence, showed greater heterogeneity among the isolates and appears to be a useful method for distinguishing among isolates of C. raciborskii.

scholarly journals Mutants affecting histidine utilization inAspergillus nidulans

1975 ◽  
Vol 25 (2) ◽  
pp. 119-135 ◽  
Author(s):  
Meryl Polkinghorne ◽  
M. J. Hynes
Keyword(s):  
Carbon Source ◽  
Nitrogen Source ◽  
Sole Carbon Source ◽  
Nitrogen Sources ◽  
Limiting Factor ◽  
Sole Nitrogen Source ◽  
Wild Type ◽  
Exogenous Substrate ◽  
Growth Properties ◽  
Type Strains

SUMMARYWild-type strains ofAspergillus nidulansgrow poorly onL-histidine as a sole nitrogen source. The synthesis of the enzyme histidase (EC. 4.3.1.3) appears to be a limiting factor in the growth of the wild type, as strains carrying the mutantareA102 allele have elevated histidase levels and grow strongly on histidine as a sole nitrogen source.L-Histidine is an extremely weak sole carbon source for all strains.Ammonium repression has an important role in the regulation of histidase synthesis and the relief of ammonium repression is dependent on the availability of a good carbon source. The level of histidase synthesis does not respond to the addition of exogenous substrate.Mutants carrying lesions in thesarA orsarB loci (suppressor ofareA102) have been isolated. The growth properties of these mutants on histidine as a sole nitrogen source correlate with the levels of histidase synthesized. Mutation at thesarA andsarB loci also reduces the utilization of a number of other nitrogen sources. The data suggest that these two genes may code for regulatory products involved in nitrogen catabolism. No histidase structural gene mutants were identified and possible explanations of this are discussed.

Molecular Insights into Beneficial Effects of Tea-Plant Growth and Selenium Enrichment by Herbaspirillum camelliae

2021 ◽  
pp. 37-51
Author(s):  
Wei Cheng ◽  
Xuejing Yu ◽  
Xingguo Wang
Keyword(s):  
Plant Growth ◽  
Molecular Mechanisms ◽  
Acc Deaminase ◽  
Nitrogen Sources ◽  
Endophytic Bacterium ◽  
Tea Plant ◽  
Nitrogen Fixing ◽  
Biotic And Abiotic Stress ◽  
Bacterial Strains ◽  
Secretion Systems

Herbaspirillum camelliae WT00C, as a tea-plant endophytic bacterium, not only colonizes specifically in tea plants but also promotes tea-plant growth and selenium enrichment. Different from diazotrophic endophytes H. seropedicae, H. frisingense and H. rubrisubalbicans, H. camelliae WT00C does not display nitrogen-fixing activity. To understand the molecular mechanisms of promoting the growth of tea plant and Se-enrichment, we sequenced and annotated the genome of H. camelliae WT00C. The results showed that the genome was composed of 6,079,821 base pairs with a total of 5,537 genes. The genomic survey also revealed that H. camelliae WT00C was a multifunctional bacterium metabolizing a variety of carbon and nitrogen sources and defending against biotic and abiotic stress. Although this bacterium did not have intact nitrogen-fixing genes, its genome held the genes responsible for indole-3-acetic acid (IAA) biosynthesis, 1-aminocyclopropane-1-carboxylate (ACC) deamination, siderophore synthesis, ammonia formation, urea metabolism, glutathione and selenocompound metabolisms. Biosynthesis of IAA, siderophore, ammonia, urea and ACC deaminase could explain why two bacterial strains promote tea-plant growth and development. Selenocompound metabolism in this bacterium might also benefit tea-plant growth and Se-enrichment. In addition, the genome of H. camelliae also contained a multitude of protein secretion systems T1SS, T3SS, T4SS and T6SS, in which T4SS did not exhibit in other members of the genus Herbaspirillum.

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