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91.
Immobilization of invertase on rice husk using polyethylenimine 总被引:2,自引:0,他引:2
Washed and dried rice husk was coated with 2% polyethylenimine (PEI). Invertase was immobilized on this support through adsorption followed by cross-linking with 2% glutaraldehyde. Immobilized enzyme was reused for the hydrolysis of sucrose without loss in activity. This approach may serve as a simple technique in the future for the covalent immobilization of enzymes on lignocellulosic supports. 相似文献
92.
Sood Anil Ahuja P.S. Sharma Madhu Sharma O.P. Godbole Savita 《Plant Cell, Tissue and Organ Culture》2002,71(1):55-63
Seedling raised elites of Dendrocalamus hamiltoniiNees et Arn. Ex Munro were chosen as the source of nodal explants from precocious branches. While axillary bud break was accomplished in hormone free 1/2MS medium containing sucrose (3%, w/v), BA supplementation was required for shoot proliferation. A variety of hormonal combinations induced rooting in clumps of shoots. Somatic embryogenesis was also obtained in callus cultures raised in 2,4-D supplemented MS medium and plantlets derived from somatic embryos were hardened for field transfer. Comparative growth performances of plants raised from nodal cuttings of field-grown plants, those from single node cuttings of precocious branches and from somatic embryos indicated that growth performance of the tissue culture raised plants was relatively better than those from nodal cuttings. Improved protocols for efficient micropropagation are visualized to provide an impetus to raising of bamboo nurseries of elite genotypes in bamboo growing areas of western Himalayas. 相似文献
93.
Volk DE Yang X Fennewald SM King DJ Bassett SE Venkitachalam S Herzog N Luxon BA Gorenstein DG 《Bioorganic chemistry》2002,30(6):396-419
A variety of monothio- and dithiosubstituted duplex aptamers targeting NF-kappaB have been synthesized and designed. The specificity and affinity of the dithioate aptamers of p50 and RelA(p65) NF-kappaB homodimers was determined by gel shift experiments. The NMR solution structures for several unmodified and dithioate backbone modified 14-base paired duplex aptamers have been determined by a hybrid, complete matrix (MORASS)/restrained molecular dynamics method. Structural perturbations of the dithioate substitutions support our hypothesis that the dithioate binds cations less tightly than phosphoryl groups. This increases the electrostatic repulsion across the B-form narrow minor groove and enlarges the minor groove, similar to that found in A-form duplexes. Structural analysis of modeled aptamer complexes with NF-kappaB homo- and heterodimers suggests that the dithioate backbone substitution can increase the aptamer's relative affinity to basic groups in proteins such as NF-kappaB by helping to "strip" the cations from the aptamer backbone. 相似文献
94.
Recombinant transformation vectors (ZPβypGH and ZpβrtGH) consisting of fish growth hormone cDNA, and a reporter geneβ-galactosidase driven by fish promoter (Zp) were constructed. Freshly fertilized eggs of zebrafish (Brachydanio rerio) were electroporated at optimum conditions (0.07 kV voltage; 25 μF capacitance; 8 ohm resistance and 2 pulses) in the presence
of one of these transformation vectors (100 μg circular DNNml). In either cases 72% of the electroporated eggs successfully
hatched, in comparison to the 85% hatchability of the control eggs. Genomic DNA extracted from fins of randomly chosenF
0 individuals was screened (by Southern blot hybridization); the transgenes were retained in the host genome of all the randomly
chosen adult transformants. Fin-positive presumptive founder parents were crossed with control counterparts and the DNA of
randomly chosenF
1 progenies was screened for germline transformation. Southern analysis of chosenF
1 progenies revealed the persistence of ZPβypGH or ZpβrtGH in 53% of theF
1 progenies. Southern analyses of chosenF
1 progenies and the frequency (53% ofF
1 ZpβrtGH and 53% ofF
1 ZP{β}ypGH) of transmission revealed the degree of mosaicism inF
0 transformants. Expression was confirmed from the 3–4 times elevated levels of activity of the reporter gene and 30–40% accelerated
growth of transgenicF
0 andF
1 progenies.
Construction of the transgenes was made at the Taiwan National Ocean University, Taiwan and all other work at the Madurai
Kamaraj University, Madurai. 相似文献
95.
In the polar fraction of the extract from Wikstroemia viridiflora, daphnoretin and a new coumarin, wikstrosin, were identified. Wikstrosin has been characterised by chemical and spectral methods as a tricoumarin, a new class not reported hitherto in nature. 相似文献
96.
Biologically active Mannich bases with heteroaromatic ring system have been synthesised employing Mannich reaction of isonicotinyl hydrazide with various sulphonamides/secondary amines. They were analysed by elemental analysis and characterized by uv, ir, 1H nmr spectroscopic studies. The Mannich bases were screened for their antibacterial activity against various gram positive and gram negative bacteria and were analyzed statistically. The results have shown that the compounds are quiet active against pathogens under study and were nontoxic. 相似文献
97.
Jiang W Alford VC Qiu Y Bhattacharjee S John TM Haynes-Johnson D Kraft PJ Lundeen SG Sui Z 《Bioorganic & medicinal chemistry》2004,12(6):1505-1515
The synthesis of the fused tetracyclic pyrroloquinolones 9a-i in four steps is described. The PDE5 inhibitory activities of these compounds, their selectivities against PDE1, PDE2, PDE3, PDE4 and PDE6, the preclinical pharmacokinetic assessments and the in vivo efficacy in increasing intracavernosal pressure are presented and discussed. 相似文献
98.
Artemis is a phosphorylation target of ATM and ATR and is involved in the G2/M DNA damage checkpoint response 下载免费PDF全文
Zhang X Succi J Feng Z Prithivirajsingh S Story MD Legerski RJ 《Molecular and cellular biology》2004,24(20):9207-9220
Mutations in Artemis in both humans and mice result in severe combined immunodeficiency due to a defect in V(D)J recombination. In addition, Artemis mutants are radiosensitive and chromosomally unstable, which has been attributed to a defect in nonhomologous end joining (NHEJ). We show here, however, that Artemis-depleted cell extracts are not defective in NHEJ and that Artemis-deficient cells have normal repair kinetics of double-strand breaks after exposure to ionizing radiation (IR). Artemis is shown, however, to interact with known cell cycle checkpoint proteins and to be a phosphorylation target of the checkpoint kinase ATM or ATR after exposure of cells to IR or UV irradiation, respectively. Consistent with these findings, our results also show that Artemis is required for the maintenance of a normal DNA damage-induced G2/M cell cycle arrest. Artemis does not appear, however, to act either upstream or downstream of checkpoint kinase Chk1 or Chk2. These results define Artemis as having a checkpoint function and suggest that the radiosensitivity and chromosomal instability of Artemis-deficient cells may be due to defects in cell cycle responses after DNA damage. 相似文献
99.
Khadikar PV Joshi S Bajaj AV Mandloi D 《Bioorganic & medicinal chemistry letters》2004,14(5):1187-1191
Aromatic stabilities of acenes and helicenes, which are responsible for their biological, environmental and cancerous behavior have been modeled using a newly introduced Sadhana (Sd) and A indices. The results are compared with those obtained from PI (Padmakar-Ivan) index. The regression analysis has shown that excellent results are obtained by considering acenes and helicenes as separate classes of isomeric benzenoid hydrocarbons and that A index is better index than both PI and Sd indices. 相似文献
100.
Obineche EN Adeghate E Chandranath IS Benedict S Al Gafri LS Adem A 《Molecular and cellular biochemistry》2004,261(1-2):3-8
In this study the effect of diabetes mellitus on atrial natriuretic peptide (ANP) receptors in streptozotocin- (STZ-) induced diabetic rat kidneys was studied. Moreover, plasma ANP concentration was evaluated in diabetic and control rats by using radioimmunoassay. In addition, the expression of ANP in the kidneys of control and diabetic rats was evaluated by immunohistochemistry. Body-weight loss and increased glucose levels were used as indices of diabetes mellitus in the STZ-induced rats. There was a significant loss in the body weight of the diabetic rats compared to controls. The efficacy of STZ administration was confirmed by rising blood glucose levels, which were significantly higher in diabetic rats compared to controls. Plasma ANP concentration was significantly greater in the diabetic rats in comparison with controls. Moreover, our immunohistochemical results show that the expression of ANP in diabetic rats was higher than that in age-matched controls. ANP was observed in the cells lining the proximal convoluted tubules in the cortex. The distribution and levels of ANP receptors in the kidneys of diabetic rats and age-matched controls were investigated using quantitative receptor autoradiography. Our results demonstrate significant decrease in ANP receptors in the kidneys of the diabetic rats compared to controls. The significant decrease was found in the juxtaglomerular medulla, inner medulla, and the papillae. The decrease in ANP receptors observed in the diabetic kidneys could have pathological consequences resulting in renal resistance to ANP in diabetes. 相似文献