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41.
Callus cultures were established from stem explants of Ruscus hypophyllum on a modified basal medium of Murashige and Skoog (1962) supplemented with 1 mg l-1 2,4-D+0.1 mg l-1 BAP. The optimal 2,4-D concentration for promoting shoot bud formation and growth was 0.05 mg l-1 along with 0.5 mg l-1 BAP. Sixty percent of rootless shoots produced flowers on the regenerating medium. Rooting was induced when shoots were transferred to half strength MS inorganic salts supplemented with 2 mg l-1 IBA. Eighty percent of plants transferred to soil have survived. 相似文献
42.
Sunil Palchaudhuri Ranajit Kumar Dipak Sen Ruma Pal Sajal Ghosh Banwarilal Sarkar Sujit K. Bhattacharya Sudhir C. Pal 《FEMS microbiology letters》1985,30(1-2):187-191
Abstract Multiple antibiotic-resistant Shigella dysenteriae type 1 isolates from a recent epidemic in West Bengal (India) showed identical plasmid patterns. All isolates were resistant to ampicillin (Am), chloramphenicol (Cm), tetracycline (Tc), streptomycin (Sm) and trimethoprim (Tp) and contained 6 plasmids, ranging from 2.5–120 kb. The Am resistance determinant was located on the 120 kb plasmid. This plasmid was unstable when the S. dysenteriae strains were grown above 37°C. The Bangladesh strains of S. dysenteriae type 1 showed identical plasmid patterns, except that many isolates were Am-sensitive and lacked the 120 kb plasmid. In strains from both Bangladesh and West Bengal, predominantly group-B plasmids conferred resistance to Cm and Tc. Comparisons of Eco R1 fragments generated from the total plasmid DNA content of each strain support the view that the plasmids present in the S. dysenteriae type 1 strains isolated from all recent epidemics in India and Bangladesh were identical. 相似文献
43.
R Rastogi S Sharma N Anand A Dutta N Fatma R K Chatterjee A B Sen 《Journal of helminthology》1984,58(3):251-254
The synthesis and filaricidal activity of 1-iso-butoxycarbonyl-4-methylpiperazine against Litomosoides carinii in Sigmodon hispidus and Dipetalonema viteae in Mastomys natalensis is reported. At an intraperitoneal or oral dose of 3 mg/kg given for 6 days, the compound removed 91% of the circulating microfilariae but had no effect on adult L. carinii. However, it killed all microfilariae and adults of D. viteae at a subcutaneous dose of 50 mg/kg given for 6 days. The compound also possessed chemoprophylactic activity against the larvae of L. carinii and D. viteae at a dose of 30 and 50 mg/kg respectively. 相似文献
44.
Summary A 6.4 Kb HindIII fragment of Bacillus stearothermophilus DY-5 DNA cloned in Escherichia coli using pBR322 as a vector was shown to direct the synthesis of a thermophilic -amylase. In attempts to reduce the size of the insert, the -amylase gene was shown to be contained in a 3.1 Kb HindIII-BamHI fragment of the donor strain DNA.The -amylase gene was stably maintained and expressed efficiently in E. coli. The enzymic properties of -amylase produced in E. coli closely resembled those of the donor strain -amylase and the temperature range for the maximal activity was from 65° C to 80° C. Nearly 100% of the activity remained after heating at 80° C for 15 min.The -amylase was shown to be accumulated in the periplasmic space. It was purified to a nearly homogenous protein with a molecular weight of 61,000, which was very similar in size to that produced by B. stearothermophilus DY-5. 相似文献
45.
Putrescine, spermidine and spermine of high vigour, low vigour and non-viable (classes 1, 2 and 3 respectively) seeds of Oryza sativa increased with loss of viability. The largest concentration of spermine was found in non-viable embryos. Spermine was absent in the husks of all the three categories of seeds. Arginine decarboxylase was greatest in high vigoured seeds and its activity gradually declined with loss of viability. However, diamine oxidase and polyamine oxidase activities gradually increased with the loss of viability of the seeds while DNA, RNA and protein contents decreased. The total content of polyamines increased on kinetin treatment but declined on ABA treatment. DNA, RNA and protein followed the same trend as polyamines. The polyamine contents increased by ca 3- and 4-fold, respectively, in high vigoured and low vigoured seeds on 10?4 M kinetin treatment. The activity of ADC followed the same change as that of the polyamines in both cases, but the reverse was observed for the activities of diamine and polyamine oxidases. 相似文献
46.
The kinetics of haemolysis of rabbit erythrocytes byCroton tiglium lectin was studied as a function of concentration of the lectin and erythrocytes. The length of the prelytic period decreased with increasing lectin concentrations, indicating that the secondary events at the membrane which follow the binding of the lectin to cell surface carbohydrate receptors are accelerated at higher surface concentrations of the lectin. The rate or extent of haemolysis was not affected by the inclusion of ions like K+, Ca2+ and Mg2+ in the medium or by the substitution of ionic medium by a non-ionic medium. The inhibition of haemagglutination and haemolysis of rabbit red cells byCroton tiglium lectin by antilectin rabbit serum was observed. A possible mechanism of haemolysis by the lectin is discussed. 相似文献
47.
A novel guanine-guanine base pairing: crystal structure of a complex between 7-methylguanosine and its iodide. 总被引:3,自引:2,他引:1 下载免费PDF全文
7-Methylguanosine, one of the biologically important minor nucleosides, could be crystallized as a complex of its zwitterionic form and its iodide, and the crystal structure was determined by the X-ray diffraction method. The crystals belong to the triclinic space group P1 with the unit cell dimensions: a = 7.678(1), b = 18.094(3), and c = 5.711(1) A, alpha = 79.32(1), beta = 80.14(1) and gamma = 76.90(1) degrees. The structure was solved by the heavy atom method and refined by the least-squares method to give a final R index of 0.075. The novel reverse Watson-Crick type base pairing observed between a positively charged molecule and a deprotonated one indicates that the deprotonation at the N(1) position promoted by the alkylation at the N(7) position may interrupt the formation of the normal Watson-Crick type GC base pair. The conformations about the glycosidic bond and the sugar puckering are quite different between the two molecules: the former has anti and C(4')-exo,C(3')-endo and the latter syn and C(1')-exo-C(2')-endo. 相似文献
48.
49.
Isolation and protein pattern of eye lens fiber junctions 总被引:13,自引:0,他引:13
50.
The X Chromosomes of Mammals: Karyological Homology as Revealed by Banding Techniques 总被引:2,自引:0,他引:2 下载免费PDF全文
A comparison of the Giemsa-banding patterns of the X chromosomes in various mammalian species including man indicates that two major bands (A and B), which are resistant to trypsin and urea-treatments, are always present irrespective of the gross morphology of the X chromosomes. This is true in all mammalian species with the "original or standard type" X chromosomes (5-6% of the haploid genome) thus far analyzed. In the unusually large-sized X chromosomes the extra chromosomal material may be due either to the addition of genetically inert constitutive heterochromatin or to an X-autosome translocation. In these X chromosomes two major bands are present in the actual X-chromosome segment. Our data on C and G band patterns also support Ohno's hypothesis that the mammalian X chromosome is extremely conservative in its genetic content, in spite of its cytogenetic variability. 相似文献