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1.
Seven barley(Hordeum vulgäre L.) cultivars tested varied greatly in their responses to root medium salinity (electrical conductivity of 3, 5, 10, 15 and 20 dS nr-1)-lant growth was relatively more adversely affected than seed germination. Dry/fresh mass ratio increased at higher salinity levels in all barley cultivars indicating reduced water uptake. Higher K/Na ratio in plant shoots compared to that in the root medium solution indicated selective uptake of K that seems to be among processes involved in tolerance of cultivars to salinity stress. 相似文献
2.
R Mahmood C Cremo K L Nakamaye R G Yount 《The Journal of biological chemistry》1987,262(30):14479-14486
The photoprobe 3'(2')-O-(4-benzoyl)benzoyladenosine 5'-triphosphate (Bz2ATP) was used to characterize the nucleotide-binding site of myosin subfragment 1 (SF1). Improved synthesis and purification of Bz2ATP are reported. 1H NMR and ultraviolet spectroscopy show that Bz2ATP is a 60:40 mixture of the 3'(2')-ribose isomers and that the epsilon M261 is 41,000 M-1 cm-1. Bz2ATP is hydrolyzed by SF1 comparably to ATP in the presence of actin or K+, NH4+, or Mg2+ ions; and the product, Bz2ADP, has a single binding site on SF1 (K'a = 3.0 X 10(5) M-1). [3H]Bz2ATP was photoincorporated into SF1 with concomitant loss of K+-EDTA-ATPase activity. Analysis of photolabeled SF1 showed that the three major tryptic peptides (23, 50, and 20 kDa) of the heavy chain fragment and the alkali light chains were labeled. The presence of ATP during irradiation protected only the 50-kDa peptide, indicating that the other peptides were nonspecifically labeled. If Bz2ATP was first trapped on SF1 by cross-linking the reactive thiols, SH1 and SH2, with p-phenylenedimaleimide, only the 50-kDa tryptic peptide was labeled. These results confirm and extend previous observations that [3H]Bz2ATP trapped on SF1 by cobalt(III) phenanthroline photolabeled the same 50-kDa peptide (Mahmood, R., and Yount, R.G. (1984) J. Biol. Chem. 259, 12956-12959). Thus, the 50-kDa peptide is labeled with or without thiol cross-linking, indicating that the relative position of SH1 and SH2 does not affect the labeling pattern. 相似文献
3.
Application of phosphorus at 40, 60, 80 and 100 kg P2O5 ha–1 in the presence of a uniform dressing of nitrogen (N) and potash (K2O) each applied at 20 and 24 kg ha–1 to chickpea (CM-88) grown in sandy loam soil in a replicated field experiment improved the nodulation response of the crop, increased its grain yield (ka ha–1) by 18, 59, 40 and 14 percent, biomass yield (ka ha–1) by 32, 32, 54 and 14 percent, biomass N (kg ha–1) by 31, 48, 49, 19 percent, and biomass P (kg ha–1) by 26, 40, 41 and 11 percent, respectively. The effect of phosphorus on the nitrogenase activity of the excised roots of chickpea was, however, inconsistent. 相似文献
4.
The interactive effect of low P supply (0, 10, 20 and 40 M) and plant age on nodule number, mass and functioning (ureide analysis technique), vegetative growth and pod production were investigated in glasshouse-grown nodulated cowpea (Vigna unguiculata L.cv. Kausband) in sand culture. Compared with 40 M P, P stress (0 M P) or very low (10 M P) supply markedly impaired nodulation, allantoin and amino-N concentrations and weight of N solutes in xylem exudates. Consequently, P stress reduced top growth and pod yields by 48 and 90%, respectively. N solutes in xylem exudates and total plant N assayed by Kjeldahl technique (as estimates of N2 fixation) responded similarly to P supply. However, the relative ureide index [(ureide-N/ureide N+amino-N)×100] remained constant (99%), irrespective of P supply, indicating the plants' complete dependency on symbiosis for growth, without implying that growth was markedly increased by N2 fixation. Although P concentrations in plant tops, roots and nodules increased with P supply, N concentrations in these plant tissues were unaffected by P supply. The concentrations of N and P in the nodules were 2–2 1/2 times higher than in plant tops. P application interacted strongly with plant age, with the largest P effect evidently achieved at the early podding stage. The significance and implications of these results are discussed. 相似文献
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A polytene chromosome map of Anopheles stephensi has been prepared from the ovarian nurse cells of adult females. Many homologous regions can be recognized in comparisons between the ovarian and salivary gland chromosome maps but band for band homologies are not readily evident. The preparation of polytene chromosomes from ovarian nurse cells is easier than from the larval salivary glands and the results more consistent. 相似文献
8.
Carl Harald Janson Mahmood Jeddi Tehrani H»kan Mellstedt Hans Wigzell 《Cancer immunology, immunotherapy : CII》1989,28(3):225-232
Summary A murine anti-idiotypic monoclonal antibody (mAb), F1, (IgG2a) was produced against the variable part of the T-cell receptor for antigen (Ti, /) on the tumor cells of a patient with T-cell chronic lymphatic leukemia (CD3+, 8+, 4–). The molecular weight of the protein reactive with mAb F1, comodulation and coprecipitation with anti-CD3 antibody, and the restricted tumor-cell reactivity strongly support the anti-idiotypic nature of mAb F1. MAb F1 also stained 4% of peripheral blood lymphocytes of healthy donors. MAb F1 did not stimulate the tumor cells to DNA synthesis, but stimulated a fraction of the normal peripheral blood lymphocytes, mAb F1 did not mediate antibody-dependent cellular cytotoxicity or complement lysis to any significant degree in vitro. Three infusions of 1–10 mg anti-idiotypic mAb were given over a period of 4 weeks. The plasma half-life for mAb F1 was 3 h in the first 2 h after infusion and 44 h from 2 h to 120 h after infusion. After each treatment a rapid decrease of circulating tumor cells was seen. During the observation period an 80% reduction of the total circulating tumor cells was noted. After the second infusion, IgM and IgG antimouse antibodies were detected. Side-effects from therapy were fever, chills, nausea, vomiting, diarrhea, tachycardia, increase in systolic blood pressure and shortness of breath. Thus, in T-cell malignancies a major reduction of circulating tumor cells can be accomplished by low doses of anti-idiotypic mAb. Anti-idiotypic mAb might be a therapeutic agent of significant importance. 相似文献
9.
Mahmood Vahedian Liang Shi Tong Zhu Ronald Okimoto Kathleen Danna Paul Keim 《Plant molecular biology》1995,29(4):857-862
Repetitive DNA sequences comprise a large percentage of plant genomes, and their characterization provides information about both species and genome evolution. We have isolated a recombinant clone containing a highly repeated DNA element (SB92) that is homologous to ca. 0.9% of the soybean genome or about 105 copies. This repeated sequence is tandemly arranged and is found in four or five major genomic locations. FISH analysis of metaphase chromosomes suggests that two of these locations are centromeric. We have determined the sequence of two cloned repeats and performed genomic sequencing to obtain a consensus sequence. The consensus repeat size was 92 bp and exhibited an average of 10% nucleotide substitution relative to the two cloned repeats. This high level of sequence diversity suggests an ancient origin but is inconsistent with the limited phylogenetic distribution of SB92, which is found an high copy number only in the annual soybeans. It therefore seems likely that this sequence is undergoing very rapid evolution. 相似文献
10.
Hamid Rashid Mohammad Najmus Saqib Abdul Aala Rajoka Muhammad Ibrahim Siddiqui Khawar Sohail 《Biotechnology Techniques》1997,11(4):245-248
A simple, sensitive, accurate and more informative assay for determining the number of modified groups during the course of carboxyl group modification is described. Monomeric carboxymethylcellulase (CMCase) from Aspergillus niger was modified by 1-ethyl-3(3-dimethylaminopropyl)carbodiimide (EDC) in the presence of glycinamide. The different time-course aliquots were subjected to non-denaturing PAGE and the gel stained for CMCase activity. The number of carboxyl groups modified are directly read from the ladder of the enzyme bands developed at given time. This method showed that after 75 min of modification reaction there were five major species of modified CMCases in which 6 to 10 carboxyls were modified. 相似文献