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Biomedical subjects

I Nur

Publications and source records attributed to I Nur.

25 records · Page 2Linked to original sources
PubMed1981

Effects of Temperature, Nitrogen Fertilization, and Plant Age on Nitrogen Fixation by Setaria italica Inoculated with Azospirillum brasilense (strain cd).

The association between the nitrogen-fixing bacterium Azospirillum brasilense (strain cd) and the grass Setaria italica was studied under different environmental and soil conditions. Highest acetylene reduction rates in intact plants were observed at the booting stage of Setaria (2350 nmol ethylene produced hour(-1) plant(-1)) at 27 C. Higher temperatures, up to 32 C, enhanced ethylene reduction. Significant increases in shoot dry weight, panicle weight, and length were obtained in inoculated plants fertilized with suboptimal NH(4)NO(3) levels. The increase in nitrogen content of plants inoculated with A. brasilense was shown to be due to N(2) fixation. This was demonstrated by growing plants in washed quartz sand with no combined nitrogen. The bacteria also increased branching and development of roots. It was concluded that inoculation of Setaria with A. brasilense may lead both to increases in plant yield and saving of nitrogen fertilizer.

Journal Article↗
PubMed1980

Increase in Dry Weight and Total Nitrogen Content in Zea mays and Setaria italica Associated with Nitrogen-fixing Azospirillum spp.

The association between nitrogen-fixing bacteria from the genus Azospirillum and the grasses Zea mays and Setaria italica was investigated in sterilized Leonard-jar assemblies. Nitrogen-fixing bacteria isolated from Cynodon dactylon roots in Israel and Azospirillum brasilense (Sp-7, Sp-80, and Cd) were examined. C(2)H(2) reduction activity was detected in systems containing 0.0 to 0.08 but not in those containing 0.16 gram per liter NH(4)NO(3). The organisms tested significantly increased plant dry weight (50-100%), total N content of leaves (50-100%) and C(2)H(4) production (300-1000 nanomoles C(2)H(4) per plant per hour). Highest C(2)H(2) reduction activities were obtained above 30 C and with high light intensities. Significant increases in S. italica dry weight (DW) and nitrogen (N) content were observed in sand (DW = 80%, N = 150%), sandy loam soil (DW = 80%, N = 75%) and loess (DW = 37%, N = 25%). The results obtained in this work clearly demonstrate the potential benefit of inoculating grasses with Azospirillum.

Journal Article↗
PubMed1980

An increase in nitrogen content of Setaria italica and Zea mays inoculated with Azospirillum.

Bacteria belonging to the genus Azospirillum isolated from Cynodon dactylon roots in Israel were compared with Azospirillum brasilense from Brazil and California for their ability to fix nitrogen in association with grasses under greenhouse conditions. The plants were grown in a system which avoided cross inoculation from the inoculated soil to the control, while maintaining the natural soil microflora and humidity level in the soil close to field capacity. The organisms tested significantly increased the dry weight of Zea mays and Setaria italica leaves, the total nitrogen content of these leaves (as measured by the Kjeldahl method), and supported acetylene reduction in intact nonsterile systems as compared with the noninoculated controls. Ethylene production in intact systems could be detected after 6h and was linear for 72h, providing a constant soil temperature (28-32 degrees C) was maintained.

Acetylene↗
PubMed1980

Comparative studies of nitrogen-fixing bacteria associated with grasses in Israel with Azospirillum brasilense.

Free-living, dinitrogen-fixing bacteria associated with roots of grasses were isolated from several locations in Israel. Bacteria with characteristics similar to those of Azospirillum were isolated from Cynodon dactylon roots and were compared with Azospirillum brasilense from Brasil (Sp-7) and from California (Cd). Colonies of the Israeli isolates were yellow and consisted of curved rods, 0.5-0.6 micron in diameter with polar flagella, whereas colonies of A. brasilense were pink (Sp-7) and red (Cd) and the cells were 1.0-1.1 micron in diameter with polar flagella. Ultraviolet absorption spectra of soluble c and membrane-bound c and b cytochromes were similar in all isolates. When grown in semisolid agar medium with or without ammonium chloride all isolates formed a growth zone below the surface. However, they grew best under aerobic conditions in liquid medium containing NH4Cl. All isolates could use salts of malate and lactate, arabinose, and galactose, but not mannitol, as sole carbon sources; they did not need biotin to shorten their lag phase. One Israeli isolate was capable of growing and fixing nitrogen with glucose as a sole carbon source. The Israeli isolates formed aggregates above pH 7.6 in liquid or semisolid medium and were capable of reducing nitrate to nitrogen gas under anaerobic conditions.

Bacteria↗
PubMedDate not supplied

Spiroplasma species share common DNA sequences among their viruses, plasmids and genomes.

Alkaline-Southern-blot analyses showed that a spiroplasma plasmid, pRA1, obtained from Spiroplasma citri (Maroc-R8A2), contained DNA sequences that were homologous to spiroplasma type 3 viruses (SV3) obtained from S. citri (Maroc-R8A2), S. citri (608) and S. mirum (SMCA). In addition, pRA1 and SV3(608) DNA shared common, but not necessarily related, sequences with extrachromosomal DNA derived from 11 Spiroplasma species or strains. Furthermore, SV3(608) had DNA homology with the chromosome from 6 distinct spiroplasmas but not with chromosomal DNA from eight other Spiroplasma species or strains. The biological function of these common sequences is unknown.

Bacteriophages↗
PubMedDate not supplied

Commercial fibrin sealants are not equivalent in a rabbit liver-resection model which quantitatively evaluates hemostasis and formation of adhesions.

A rabbit partial liver resection model was used to determine the hemostatic effectiveness of a new fibrin sealant. Persistent bleeding, with a mean bleeding time of 372 s and blood loss of 18 ml, from a resected lobe of the liver was achieved after rabbits in the untreated control group had been infused continuously with unfractionated heparin over 20 min with 0.2 IU/ml at a rate of 1 ml/min. Spraying the resected surface with the new fibrin sealant, Quixil, reduced bleeding to < 1 ml and the post-resection bleeding times was 25 s. Bleeding time, blood loss and the volume of sealant used in the rabbit model were inversely correlated with the thrombin concentration in the sealant. In direct comparisons with Tissucol and Beriplast, Quixil was associated with the shortest bleeding times, the lowest volume of sealant used and the lowest score of abdominal adhesions.

Aerosols↗