scholarly journals In vivo transposon tagging in the nonheterocystous nitrogen‐fixing cyanobacterium Leptolyngbya boryana

FEBS Letters ◽  
2018 ◽  
Vol 592 (10) ◽  
pp. 1634-1642 ◽  
Author(s):  
Chie Tomatsu ◽  
Kazuma Uesaka ◽  
Hisanori Yamakawa ◽  
Tohru Tsuchiya ◽  
Kunio Ihara ◽  
...  
Keyword(s):  
Transposon Tagging ◽  
Nitrogen Fixing

Characterization of an ineffective actinorhizal microsymbiont, Frankia sp. EuI1 (Actinomycetales)

1980 ◽  
Vol 26 (9) ◽  
pp. 1072-1089 ◽  
Author(s):  
Dwight Baker ◽  
William Newcomb ◽  
John G. Torrey
Keyword(s):  
Host Range ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Host Cells ◽  
Vesicle Formation ◽  
Nitrogen Fixing ◽  
Elaeagnus Umbellata

The actinomycete, Frankia sp. EuI1, isolated from root nodules of Elaeagnus umbellata is an infective endophyte but which lacks the ability to form an effective nitrogen-fixing symbiosis with its host. This ineffective organism can be distinguished easily from other frankiae, in vitro, on the basis of size, morphology, and the elaboration of a diffusible pigment. Cross-inoculation studies indicated that the host range of this symbiont is narrow and probably restricted to the Elaeagnaceae. In all cases of nodulation the symbiosis never developed nitrogenase activity and the microsymbiont never produced endophytic vesicles within the infected host cells. Sporangia were produced in vivo and in vitro so the morphogenetic block is apparently restricted to vesicle formation.

scholarly journals Activation of the symbiosis of free nitrogen-fixing bacteria with plants by an additional influx of photosynthesis products to the roots

2020 ◽  
Author(s):  
V. I. Chikov ◽  
G. A. Akhtyamova ◽  
L. A. Khamidullina
Keyword(s):  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Plant System ◽  
Additional Nitrogen

An in vivo technology is proposed that enhances the export of assimilates from leaves to roots. The possibility of thus increasing the mass of the roots and the formation of additional nitrogen in the soil-plant system is shown.

The use of metronidazole to study pyridine nucleotide reduction in vivo in Azotobacter vinelandii

1989 ◽  
Vol 35 (2) ◽  
pp. 340-343
Author(s):  
Jay B. Peterson
Keyword(s):  
Fluorescence Spectroscopy ◽  
Electron Acceptor ◽  
Azotobacter Vinelandii ◽  
Pyridine Nucleotide ◽  
Nitrogen Fixing ◽  
Whole Cell

Flavins of the particulate and supernatant fractions from nitrogen-fixing Azotobacter vinelandii cells were examined by fluorescence spectroscopy for reduction by NAD(P)H in the absence and presence of the low potential electron acceptor metronidazole. The objective was to determine if reduction of metronidazole-oxidized flavin in vivo results from NAD(P)H generation. Flavin was almost completely reduced by NADH, but NADPH gave less reduction. Most of the flavin was reduced in the presence of metronidazole. Menadione bisulfite prevented reduction. In whole-cell studies, mannitol-generated NAD(P)H reduced flavin in the presence of menadione bisulfite. These results establish that reduction of metronidazole-oxidized cell flavin in vivo is an indicator of NAD(P)H production.Key words: metronidazole, NAD(P)H reduction, Azotobacter vinelandii.

Standardization of Suitable Substrate and Buffer Solutions for Optimum in-vivo Nitrate Reductase Activity in the Leaves of Sesbania rostrata Bremek. and Oberm.

2016 ◽  
Vol 39 (2) ◽  
pp. 121-124
Author(s):  
S.P. Chaukiyal ◽  
Vandana ◽  
Poornima Uniyal
Keyword(s):  
Nitrate Reductase ◽  
Phosphate Buffer ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Sesbania Rostrata ◽  
Nitrogen Fixing ◽  
Fast Growing ◽  
Buffer Solutions ◽  
Substrate Concentrations

Sesbania rostrata Bremek. and Oberm. is a multipurpose and exceptionally fast growing nitrogen fixing plant. In this study a protocol for the standardization of in-vivo nitrate reductase (NR) assay with respect to substrate concentrations along with buffer pH and concentrations was carried out in the leaves of S. rostrata. Different substrate (KNO3) concentration ( i.e. 0.025M, 0.05M, 0.10M, 0.15M, 0.20M ) were tried against phosphate buffer (KH2PO4) solutions with different pH (6.5, 7.0, 7.5, 7.6, 7.7, 7.8 ). Maximum leaf in-vivo nitrate reductase activity was observed in 0.10 M phosphate buffer (KH2PO4) concentration of pH 7.5 with 0.15M substrate (KNO3) concentration.

Regulatory Properties of Glutamine Synthetase from the Nitrogen-Fixing Phototrophic Bacterium Rhodopseudomonas palustris

1981 ◽  
Vol 36 (9-10) ◽  
pp. 784-789 ◽  
Author(s):  
Kassem Alef ◽  
Walter G. Zumft
Keyword(s):  
Catalytic Activity ◽  
Glutamine Synthetase ◽  
Kinetic Parameters ◽  
Rhodopseudomonas Palustris ◽  
Nitrogen Fixing ◽  
Substrate Interaction ◽  
Phototrophic Bacterium ◽  
Enzyme Substrate ◽  
Regulatory Properties

Abstract Rhodopseudomonas palustris, Glutamine Synthetase Regulation, Adenylylation Glutamine synthetase from Rhodopseudomonas palustris is regulated via an adenylylation/deadenylylation mechanism. The enzyme purified from ammonia-grown cells, released AMP upon treatment with phosphodiesterase, along with drastic changes in its pH and metal dependency. Kinetic parameters for enzyme-substrate interaction were also dependent on the adenylylation state of the enzyme, as was the influence of several nitrogenous feedback inhibitors on the catalytic activity. The adenylylation state of the enzyme was modified in vivo by the availability of ammonia.

scholarly journals Development and Application of a dapB-Based In Vivo Expression Technology System To Study Colonization of Rice by the Endophytic Nitrogen-Fixing Bacterium Pseudomonas stutzeri A15

2003 ◽  
Vol 69 (11) ◽  
pp. 6864-6874 ◽  
Author(s):  
Hans Rediers ◽  
Victoria Bonnecarrère ◽  
Paul B. Rainey ◽  
Kelly Hamonts ◽  
Jos Vanderleyden ◽  
...  
Keyword(s):  
Synthetic Medium ◽  
Pseudomonas Stutzeri ◽  
Nitrogen Fixing ◽  
Free Living ◽  
Technology System ◽  
In Vivo Expression ◽  
Rice Strain ◽  
Promote Plant Growth ◽  
Transcriptional Fusions

ABSTRACT Pseudomonas stutzeri A15 is a nitrogen-fixing bacterium isolated from paddy rice. Strain A15 is able to colonize and infect rice roots. This strain may provide rice plants with fixed nitrogen and hence promote plant growth. In this article, we describe the use of dapB-based in vivo expression technology to identify P. stutzeri A15 genes that are specifically induced during colonization and infection (cii). We focused on the identification of P. stutzeri A15 genes that are switched on during rice root colonization and are switched off during free-living growth on synthetic medium. Several transcriptional fusions induced in the rice rhizosphere were isolated. Some of the corresponding genes are involved in the stress response, chemotaxis, metabolism, and global regulation, while others encode putative proteins with unknown functions or without significant homology to known proteins.

Fine Structural Changes in the Microvasculature of the Mouse Pinna: Aging and Radiation Injury

1974 ◽  
Vol 32 ◽  
pp. 54-55
Author(s):  
S. Phyllis Steamer ◽  
Rosemarie L. Devine
Keyword(s):  
Structural Changes ◽  
Radiation Treatment ◽  
Arterial Stenosis ◽  
Ultrastructural Changes ◽  
Vascular Effects ◽  
Microvascular Changes ◽  
Surrounding Connective Tissue ◽  
Fission Neutrons ◽  
Total Body

The importance of radiation damage to the skin and its vasculature was recognized by the early radiologists. In more recent studies, vascular effects were shown to involve the endothelium as well as the surrounding connective tissue. Microvascular changes in the mouse pinna were studied in vivo and recorded photographically over a period of 12-18 months. Radiation treatment at 110 days of age was total body exposure to either 240 rad fission neutrons or 855 rad 60Co gamma rays. After in vivo observations in control and irradiated mice, animals were sacrificed for examination of changes in vascular fine structure. Vessels were selected from regions of specific interest that had been identified on photomicrographs. Prominent ultrastructural changes can be attributed to aging as well as to radiation treatment. Of principal concern were determinations of ultrastructural changes associated with venous dilatations, segmental arterial stenosis and tortuosities of both veins and arteries, effects that had been identified on the basis of light microscopic observations. Tortuosities and irregularly dilated vein segments were related to both aging and radiation changes but arterial stenosis was observed only in irradiated animals.

Induction and Differentiation of Dental Epithelium in Vivo and in Vitro

1982 ◽  
Vol 40 ◽  
pp. 142-145
Author(s):  
E. J. Kollar
Keyword(s):  
Connective Tissue ◽  
Oral Mucosa ◽  
Basal Lamina ◽  
Functional Derivatives ◽  
Specific Source ◽  
Dental Epithelium ◽  
Connective Tissue Stroma

The differentiation and maintenance of many specialized epithelial structures are dependent on the underlying connective tissue stroma and on an intact basal lamina. These requirements are especially stringent in the development and maintenance of the skin and oral mucosa. The keratinization patterns of thin or thick cornified layers as well as the appearance of specialized functional derivatives such as hair and teeth can be correlated with the specific source of stroma which supports these differentiated expressions.

Ultrastructural Correlations between Clonal Human Tumor Colonies and in Vivo Neoplasms

1982 ◽  
Vol 40 ◽  
pp. 210-211
Author(s):  
M.J. Murphy ◽  
R.R. Price ◽  
J.C. Sloman
Keyword(s):  
Cultured Cells ◽  
Human Tumor ◽  
Cell Type ◽  
Tumor Mass ◽  
Initial Cell ◽  
Cloning Assay ◽  
Human Tumor Cloning ◽  
The Relationship

The in vitro human tumor cloning assay originally described by Salmon and Hamburger has been applied recently to the investigation of differential anti-tumor drug sensitivities over a broad range of human neoplasms. A major problem in the acceptance of this technique has been the question of the relationship between the cultured cells and the original patient tumor, i.e., whether the colonies that develop derive from the neoplasm or from some other cell type within the initial cell population. A study of the ultrastructural morphology of the cultured cells vs. patient tumor has therefore been undertaken to resolve this question. Direct correlation was assured by division of a common tumor mass at surgical resection, one biopsy being fixed for TEM studies, the second being rapidly transported to the laboratory for culture.

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