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11.
12.
Dr. Suvendra Nath Bagchi Paramjeet Kaloya Prakash Singh Bisen 《Current microbiology》1987,15(2):61-65
The control operative on the nitrate reductase enzyme system of host cyanobacteriumNostoc muscorum was studied after being infected with the cyanophage N-1. Phage infection lifted the host nitrate reductase activity level via accelerating the enzyme synthesis. It was found that the phage-mediated increase in the molybdenum cofactor synthesis was a major contributing factor for apparent elevated nitrate reductase level of the host. This process was inhibited in the presence of erythromycin and tungsten, the inhibitors of protein synthesis and new nitrate reductase synthesis respectively. While the preformed nitrate reductase of healthy cyanobacterium was inhibited by hydrogen peroxide, an oxidizing photosynthetic product, the same enzyme of infected cells remained virtually insensitive to this inhibitor. These data suggest involvement of new nitrate reductase synthesis and its resistance to oxidative inactivation as joint factors controlling the characteristic high enzyme level of host cyanobacterium. 相似文献
13.
14.
Data on the physico-chemical properties of proteins from soybean, groundnut, sesame seed, sunflower seed, safflower seed,
mustard seed, rapeseed and cotton seed are fairly extensive. An examination of the available data on high molecular weight
proteins suggests that there are similarities in many of their properties. In this report the similarity in amino acid composition,
size and shape, molecular weight, secondary structure, subunit composition, association-dissociation at high and low pH, stability
towards denaturants, hydrolysis by enzymes and quaternary structure of the high molecular weight proteins is discussed. Based
on these similarities a model has been proposed for the associationdissociation, denaturation and reassociation behaviour
of the high molecular weight proteins of oilseeds. 相似文献
15.
Summary Soybean plants were grown in pots with or without vesicular-arbuscular myocorrhizal (VAM) fungi in three soils of low plant-available
P content, different texture and different water-holding capacities. Mineral nutrients, except P, were provided in a complete
nutrient solution. The biomass of non-VAM plants was positively and fungal colonization negatively correlated with increasingly
coarse soil texture. There was no correlation of soil P with host or endophyte growth. Plant growth enhancement was positively
correlated with soil water content at −1.5 MPa. These observations suggest soil water status and the mycorrhizal condition
interact in influencing plant growth. 相似文献
16.
Molecular cloning and expression of Rhizobium fredii USDA 193 nodulation genes: extension of host range for nodulation. 总被引:6,自引:3,他引:3
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N Ramakrishnan R K Prakash S Shantharam N M Duteau A G Atherly 《Journal of bacteriology》1986,168(3):1087-1095
DNA hybridization with the cloned nodulation region of Rhizobium meliloti as a probe revealed DNA homology with four HindIII fragments, 12.5, 6.8, 5.2, and 0.3 kilobases (kb) in size, of the symbiotic plasmid pRjaUSDA193. Both hybridization and complementation studies suggest that the common nodulation genes nodABC and nodD of R. fredii USDA 193 are present on the 5.2-kb HindIII and 2.8-kb EcoRI fragments, respectively, of the Sym plasmid. Both fragments together could confer nodulation ability on soybeans when present in Sym plasmid-cured (Sym-) and wild-type (Sym+) Rhizobium strains or in a Ti plasmid-cured Agrobacterium tumefaciens strain. Furthermore, the 2.8-kb EcoRI fragment alone was able to form nodulelike structures on Glycine max L. cv. "Peking" (soybean). Microscopic examination of these nodules revealed bacterial invasion of the cells, probably via root hair penetration. Bacterial strains harboring plasmids carrying the 5.2- and 2.8-kb nod fragments elicited root-hair-curling responses on infection. These data suggest that the genes responsible for host range determination and some of the early events of nodulation may be coded for by the 5.2-kb HindIII and 2.8-kb EcoRI fragments. 相似文献
17.
18.
Conservation of symbiotic nitrogen fixation gene sequences in Rhizobium japonicum and Bradyrhizobium japonicum. 总被引:11,自引:6,他引:5
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Southern hybridization with nif (nitrogen fixation) and nod (nodulation) DNA probes from Rhizobium meliloti against intact plasmid DNA of Rhizobium japonicum and Bradyrhizobium japonicum strains indicated that both nif and nod sequences are on plasmid DNA in most R. japonicum strains. An exception is found with R. japonicum strain USDA194 and all B. japonicum strains where nif and nod sequences are on the chromosome. In R. japonicum strains, with the exception of strain USDA205, both nif and nod sequences are on the same plasmid. In strain USDA205, the nif genes are on a 112-megadalton plasmid, and nod genes are on a 195-megadalton plasmid. Hybridization to EcoRI digests of total DNA to nif and nod probes from R. meliloti show that the nif and nod sequences are conserved in both R. japonicum and B. japonicum strains regardless of the plasmid or chromosomal location of these genes. In addition, nif DNA hybridization patterns were identical among all R. japonicum strains and with most of the B. japonicum strains examined. Similarly, many of the bands that hybridize to the nodulation probe isolated from R. meliloti were found to be common among R. japonicum strains. Under reduced hybridization stringency conditions, strong conservation of nodulation sequences was observed in strains of B. japonicum. We have also found that the plasmid pRjaUSDA193, which possess nif and nod sequences, does not possess sequence homology with any plasmid of USDA194, but is homologous to parts of the chromosome of USDA194. Strain USDA194 is unique, since nif and nod sequences are present on the chromosome instead of on a plasmid as observed with all other strains examined. 相似文献
19.
The nucleotide sequence of the RAD3 gene of Saccharomyces cerevisiae: a potential adenine nucleotide binding amino acid sequence and a nonessential acidic carboxyl terminal region. 总被引:28,自引:9,他引:19
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The RAD3 gene of Saccharomyces cerevisiae is required for excision of pyrimidine dimers and is essential for viability. We present the nucleotide sequence of the RAD3 protein coding region and its flanking regions, and the deduced primary structure of the RAD3 protein. In addition, we have mapped the 5' end of RAD3 mRNA. The predicted RAD3 protein contains 778 amino acids with a calculated molecular weight of 89,779. A segment of the RAD3 protein shares homology with several adenine nucleotide binding proteins, suggesting that RAD3 protein may react with ATP. The twenty carboxyl terminal amino acids of RAD3 protein are predominantly acidic; however, deletion of this acidic region has no obvious effect on viability or DNA repair. 相似文献
20.
Katalin Rostas Prakash Rao Sista John Stanley Desh Pal S. Verma 《Molecular & general genetics : MGG》1984,197(2):230-235
Summary We report here successful mutagenesis with Transposon Tn5 of three slow-growing strains of Rhizobium japonicum USDA 122, 61A76, USDA 74 and one fast-growing strain, USDA 191. Strains were chosen as representatives of different DNA homology and serogroups of this divergent species, which effectively nodulate North American soybean cultivars. The source of Tn5 was the suicide plasmid pGS9, which possesses broad host range N-type transfer genes in a narrow host range p15A replicon. The selection of Tn5 mutants was facilitated by the expression of the Tn5 encoded streptomycin gene in R. japonicum. Kanamycin and streptomycin resistant colonies appeared from interspecific crosses with E. coli at optimal frequencies of 10-6 for R. japonicum USDA 61A76 and USDA 191 and 5x10-7 for R. japonicum USDA 122 and USDA 74. Altogether, 6550 Tn5 mutants were isolated in USDA 122 and 61A76, and a small number from USDA 74 and USDA 191. Colony hybridization showed that all tested mutants of 61A76 and USDA 122 contained Tn5. Physical analysis of total DNAs from representative numbers of USDA 122, 61A76 and USDA 191 mutants revealed that each of them carried one copy of the transposon integrated randomly in the genome. This was also true for most USDA 74 mutants. Screening of mutants for auxotrophy showed frequencies of 0.2% for USDA 122 and 0.08% for 61A76. Several symbiotically defective mutants were identified on plants, Glycine soja and G. max. 相似文献