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61.
A water-insoluble glucan, PFPSIN, has been isolated from the aqueous extract of an edible mushroom Pleurotus florida. On the basis of total acid hydrolysis, methylation analysis, periodate oxidation, Smith degradation, and (13)C NMR experiments, the repeating unit of the polysaccharide was established as Conformational analysis revealed the triple helical conformation of this glucan. 相似文献
62.
The synthesis of two glucose-templated (GlcT) lysine analogs GlcTK and GlcTk in which the side chain of D- and L-lysine (k and K) is conformationally constrained via incorporation into a D-glucose scaffold is described. A key-step in the synthesis is a high yielding, reductive ring opening of an exocyclic glucose-derived epoxide to form a alpha-hydroxy ester that can be converted into GlcTK and GlcTk. To demonstrate the use of these building blocks in peptide synthesis, we replaced D-lysine in the antimicrobial dipeptide sequence kW-OBn (W=L-tryptophan) and determined the antibacterial activity against various gram-positive and gram-negative organisms. Our results show that the replacement of D-lysine by unprotected GlcTk in dipeptide kW-OBn results in reduced antibacterial activity. 相似文献
63.
Ghosh K Chandra K Roy SK Mondal S Maiti D Das D Ojha AK Islam SS 《Carbohydrate research》2008,343(2):341-349
A water-soluble polysaccharide was isolated from the aqueous extract of the stem of Lagenaria siceraria. The polysaccharide was found to be constituted of methyl d-galacturonate, 2-O-methyl-D-xylose, and d-xylose in a ratio of 1:1:1. On the basis of total acid hydrolysis, methylation analysis, periodate oxidation, NMR studies ((1)H, (13)C, 2D-COSY, TOCSY, NOESY, HSQC, and HMBC), and MALDI-TOF MS analysis, the structure of the repeating unit of the polysaccharide is determined as. 相似文献
64.
3′(2′),5′-Bisphosphate nucleotidase, (EC 3.1.3.7) (BPntase) is a ubiquitous enzyme. Recently, these enzymes have drawn considerable attention as in vivo targets of salt toxicity as well as therapeutic targets of lithium that is used for the treatment of manic-depressive disorders. They belong to the Mg2+-dependent Li+-sensitive phosphomonoesterase super-family and are highly sensitive to lithium and sodium ions. However, the molecular mechanism of inhibition of this group of enzymes by monovalent cations has not been completely understood. Previously we have identified a BPntase (Dhal2p) from a highly halotolerant yeast Debaryomyces hansenii. Molecular characterization revealed a number of unique features in Dhal2p, indicating this is an extraordinary member of the family. In this study, we have carried out the structure-function analysis of Dhal2p through the combination of molecular modeling and in vitro mutagenesis approach. We have not only provided the explanation for the role played by the functionally important elements that are conserved among the members of this family but also identified important, novel structural elements in this enzyme. Our study for the first time unraveled the role of a flap as well as a loop region in the functioning of this enzyme. Most importantly, mutations in the loop region resulted in the creation of a BPntase that was insensitive to salt. 相似文献
65.
66.
This paper deals with the production of pollen grains per anther per flower of 15 probably allergenic pollen producing angiospermic
plant taxa growing in Eastern India. The selected plant taxa includesAilanthus excelsa, Alstonia scholaris, Argemone mexicana, Azadirachta indica, Cassia alata, C. siamea, Dalbergia sissoo, Holarrhena
pubescens, Lagerstroemia speciosa, Madhuca indica, Milletia pinnata, Mimusops elengi, Morus alba, M. indica andMurraya paniculata. Among the investigated taxa,A. excelsa produces the highest number of pollen grains (1635180) followed byC. siamea (1589245) andA. mexicana (463800). The production of pollen grains is lowest inH. pubescens (2500), followed byA. scholaris (5175),A. indica (6220) andM. paniculata (11200). 相似文献
67.
Cloning and characterization of thermotolerant xylitol dehydrogenases from yeast Pichia angusta 总被引:1,自引:0,他引:1
Dipanwita Biswas Manish Datt Kaliannan Ganesan Alok K. Mondal 《Applied microbiology and biotechnology》2010,88(6):1311-1320
Pichia angusta (syn. Hansenula polymorpha) represents one of the rare yeast that can grow and ferment both xylose and glucose at higher temperature (50°C). However,
little is known about the enzymes involved in xylose utilization from this species. Previous studies indicated the presence
of one xylose reductase and two xylitol dehydrogenase genes in P. angusta. In this study, we have expressed both xylitol dehydrogenases (PaXdh1p and PaXdh2p) in Escherichia coli and purified them as 6X-Histidine-tagged proteins. Biochemical characterization of the recombinant proteins reveals that
both PaXdh1p and PaXdh2p are thermotolerant enzymes. PaXdh2p contains a catalytic and a structural Zn atom. However, the structural
Zn atom is not present in PaXdh1p. Both enzymes also differ in their affinity for the substrate as well as in the catalytic
efficiency. Through mutagenesis and modeling approaches, we have also identified residues important for catalysis and substrate
binding. 相似文献
68.
69.
Singh Hemant Kumar Mondal Som Arunachalam Balraj Soman Anishkumar Sharma Pratibha Solanki C. S. 《Plasmonics (Norwell, Mass.)》2018,13(2):705-714
Plasmonics - In this paper, focus is on the light trapping surface in crystalline silicon (c-Si) solar cells where thinner c-Si wafers are expected to be used by industry to reduce the cost of cell... 相似文献
70.
Cultivated groundnut (Arachis hypogaea L.) is considered as one of the primary oilseed crops and a major fodder for cattle industry in most of the developing countries, owing to its rich source of protein. It is due to its geocarpic nature of growth that the overall yield performance of groundnut is hindered by several biotic and abiotic stress factors. Multidimensional attempts were undertaken to combat these factors by developing superior groundnut varieties, modified with integral mechanism of tolerance/resistance; however this approach proved to be futile, owing to inferior pod and kernel quality. As a superior alternative, biotechnological intervention like transformation of foreign genes, either directly (biolistic) or via Agrobacterium, significantly aided in the development of advanced groundnut genotypes equipped with integral resistance against stresses and enhanced yield attributing traits. Several genes triggered by biotic and abiotic stresses, were detected and some of them were cloned and transformed as major parts of transgenic programmes. Application of modern molecular biological techniques, in designing biotic and abiotic stress tolerant/resistant groundnut varieties that exhibited mechanisms of resistance, relied on the expression of specific genes associated to particular stress. The genetically transformed stress tolerant groundnut varieties possess the potential to be employed as donor parents in traditional breeding programmes for developing varieties that are resilient to fungal, bacterial, and viral diseases, as well as to draught and salinity. The present review emphasizes on the retrospect and prospect of genetic transformation tools, implemented for the enhancement of groundnut varieties against key biotic and abiotic stress factors. 相似文献