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21.
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Improved synthesis of oligodeoxyribonucleotide using 3-methoxy-4-phenoxybenzoyl group for amino protection. 总被引:1,自引:1,他引:0 下载免费PDF全文
3-Methoxy-4-phenoxybenzoyl group has been used for the protection of exocyclic amino group of nucleosides. In case of 2'-deoxycytidine it has been found to be highly selective under controlled conditions. The N-protected derivatives of 2'-deoxyadenosine and 2'-deoxyguanosine have been found to be sufficiently stable towards acids minimising depurination under conditions of synthesis of oligodeoxyribonucleotide on solid support via phosphotriester approach. The high lipophilicity of the group and milder deprotection conditions are additional advantages. 相似文献
23.
Summary Organic matter has been found to be closely associated with the retention of manganese in an exchangeable form. The destruction of organic matter or its addition decrease or increase the exchangeable form of manganese respectively.The removal of iron and Fe2O3 addition greatly affect the retention of manganese. An increase in Fe2O3 addition increases the retained, reducible and fixed forms (R, r and F values) of manganese in soils. 相似文献
24.
Summary The use of paraffin bait technique in the isolation ofNocardia asteroides has been tested in 241 samples of sputa obtained from 235 cases of respiratory diseases.N. asteroides was recovered on 6 occasions from sputum of a patient using the paraffin bait technique. On the other hand cultures of sputa from the same patient on routine agar media such as Sabouraud's agar and Lowenstein Jensen medium yielded only one isolated of the pathogen.This work forms a part of the Ph. D. thesis of P.V.K. submitted to the University of Delhi. 相似文献
25.
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J R Howe T C Lairmore S K Mishra S Dou R Veile S A Wells Jr H Donis-Keller 《American journal of human genetics》1992,51(6):1430-1442
Gene(s) for the autosomal dominant endocrine cancer syndromes, multiple endocrine neoplasia type 2A (MEN2A), multiple endocrine neoplasia type 2B (MEN2B), and familial medullary thyroid carcinoma (MTC1) all map to the pericentromeric region of chromosome 10. Predictive testing for the inheritance of mutant alleles in individuals at risk for these disorders has been limited by the availability of highly informative and closely linked flanking markers. We describe the development of eight new markers, including two PCR-based dinucleotide repeat polymorphisms and six RFLPs that flank the disease loci. One of the dinucleotide repeat markers (sJRH-1) derives from the RBP3 locus on 10q11.2 and has a PIC of .88. The other dinucleotide repeat (sTCL-1) defines a new locus, D10S176, that maps by in situ hybridization to 10p11.2 and has a PIC of .68. We have constructed a new genetic linkage map of the pericentromeric region of chromosome 10, on the basis of 13 polymorphisms at six loci, which places the MEN2A locus between the dinucleotide repeat markers, with odds of 5,750:1 over the next most likely position. Using this set of markers, predictive genetic testing of 130 at-risk individuals from six families segregating MEN2A revealed that 95% were jointly informative with flanking markers, representing a significant improvement in genetic testing capabilities. 相似文献
27.
It is clear that C. albicans lipids have gained tremendous importance in recent years. In addition to being a barrier for entrance of various metabolites, it also provides the site of action for the synthesis of enzyme(s) involved in cell wall morphogenesis and antifungal action. While alterations in lipid composition during a yeast to mycelia transition have been observed, in most of the studies, lipid fluctuations reported could have been due to various environmental factors involved in the induction of morphogenesis [4,5]. A clear understanding of lipid biosynthesis and metabolic blocks due to antifungal action is likely to shed further light on selective interactions of antifungals. Despite the multifacet role of lipids in various functions of this pathogenic yeast, their exact involvement is poorly understood. The situation is little better with regard to ergosterol and its metabolism. Ergosterol is, indeed, important for anti-candidal activity and appears to be involved in the morphogenesis of C. albicans. The fluctuation in phospholipid composition have led to altered properties of plasma membrane namely, membrane fluidity, transport activities and drug sensitivity, which suggest that-a critical level of individual phospholipid is important for proper functioning of the plasma membrane. What the exact role is of individual phospholipid is far from clear. Many unanswered questions relating to the role of PI and sphingomyelin in signal transduction, involvement of phospholipases in the maintenance of phospholipid composition, and role of lipid transfer proteins in assembly and asymmetry of lipids are some aspects which merit further work. 相似文献
28.
Ian T. Forrester Anthony C. Grabski Chittra Mishra Brian D. Kelley W. Nick Strickland Gary F. Leatham Richard R. Burgess 《Applied microbiology and biotechnology》1990,33(3):359-365
Summary Extracellular culture filtrates from ligninolytic cultures of the lignin-degrading basidiomycete Lentinula (syn. Lentinus) edodes (Berk.) Pegler contained one major peroxidase when grown on a commercial oak-wood substrate. The peroxidase was purified by polyethylenimine clarification, anion-exchange chromatography, and hydrophobic-interaction HPLC. The enzyme (MnP1) was a heme-iron protein with an apparent molecular weight of 44 600 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels and an isoelectric point of pH 3.2. The native enzyme had an absorption maximum at 407 nm, which shifted to 420 nm upon H2O2 addition. The pyridine-hemochrome-absorption spectrum indicated that one heme group was present per enzyme as protoporphyrin IX. N-terminal amino acid sequencing showed that MnP1 had higher sequence homology with manganese peroxidases than with lignin peroxidases reported from Phanerochaete chrysosporium. L. edodes MnP1 was capable of oxidizing lignin and lignin-model compounds in the presence of manganese and H2O2.On leave from the Department of Biochemistry, University of Otago, P. O. Box 56, Dunedin, New Zealand.Research carried out while a visiting scientist at the USDA Forest Products Laboratory from the National Chemistry Laboratory, Pune, India 41 1008
Offprint requests to: I. T. Forrester 相似文献
29.
The effect of Ca2+ and Mg2+ on relative fluidity of phosphatidylcholine liposomes was studied by measuring the degree of chlorophyll fluorescence polarization.
An increase in the degree of fluorescence polarization was observed on incubation of liposomes with different concentrations
of Ca2+ or Mg2+. The results have been interpreted on the basis of increase in the size of liposomes which could be brought about by calcium
or magnesium induced fusion of small unilamellar liposomes to form larger vesicles. Fusion of liposomes has also been confirmed
by the experiments on efficiency of energy transfer from chlorophyll b to chlorophyll a, and transmission electron microscopy
of liposomes before and after incubation with Ca2+ and Mg2+. 相似文献
30.
Airborne fungi were monitored at five sample sites with the Burkard portable, the RCS Plus, and the SAS Super 90 air samplers; the Andersen 2-stage impactor was used for comparison. All samplers were calibrated before being used simultaneously to collect 100-liter samples at each site. The Andersen and Burkard samplers retrieved equivalent volumes of airborne fungi; the SAS Super 90 and RCS Plus measurements did not differ from each other but were significantly lower than those obtained with the Andersen or Burkard samplers. Total fungal counts correlated linearly with Cladosporium and Penicillium counts. Alternaria species, although present at all sites, did not correlate with total count or with amounts of any other fungal genera. Sampler and location significantly influenced fungal counts, but no interactions between samplers and locations were found. 相似文献