Chemical analysis of a new (1-->3)-, (1-->6)-branched glucan from an edible mushroom, Pleurotus florida

A glucan that was soluble in aqueous sodium chloride was isolated from the aqueous extract of the fruiting bodies of Pleurotus florida. On the basis of total hydrolysis, methylation analysis, periodate oxidation, Smith degradation, and NMR studies (1H, 13C, TOCSY, DQF-COSY, NOESY, and HSQC), the structure of the repeating unit of the polysaccharide is established as: This glucan stimulates the phagocytic activity of macrophages.     

Structural investigation of a polysaccharide (Fr. II) isolated from the aqueous extract of an edible mushroom, Pleurotus sajor-caju

A water-soluble polysaccharide, (Fr. II) isolated from aqueous extract of an edible mushroom Pleurotus sajor-caju, was found to consist of D-glucose, D-galactose, and D-mannose in a molar proportion of 1:1:1. Compositional analysis, methylation analysis, periodate oxidation study, partial hydrolysis, and NMR experiments ((1)H, (13)C, 2D-COSY, TOCSY, NOESY, HSQC, and HMBC) revealed the presence of the following repeating unit in the polysaccharide: [formula: see text]     

Sodium nitroprusside relaxes goat coronary artery through activation of calcium-dependent K+ channels

In the present investigation we have examined the hypothesis that calcium-dependent K+ channels (K(Ca)) are involved in the sodium nitroprusside (SNP)-induced vasodilatation of goat coronary artery. SNP (10(-9)-3 x 10(-6) M), added cumulatively, relaxed K+ (30 mM)-contracted coronary artery ring segments in a concentration-dependent manner with an EC50 of 1.32 x 10(-7) M (95% CL, 0.93-1.86 x 10(-7) M; n = 21). K(Ca) blocker, tetraethyl ammonium (1 mM) caused a rightward shift in the concentration-response curve of SNP with a corresponding increase in EC50 (1.62 x 10(-6) M; 95% CL, 0.44-6.02 x 10(-6) M, n = 4) of nitro vasodilator. Lowering of extra cellular Ca2+ in the physiological saline solution to 1/4 of normal selectively attenuated the vasorelaxant response of SNP, thereby causing an increase in its EC50 (2.4 x 10(-6) M; 95% CL, 1.23-4.68 x 10(-6) M, n = 4). Exposure of the tissues to high K+ (80 mM) solution, a protocol adopted to reduce the K+ gradient across the cell membrane, markedly inhibited the coronary artery relaxations induced by SNP (EC50, 2.54 x 10(-6) M; 95% CL, 1.31-4.91 x 10(-6) M, n = 4), when compared with tissues contracted with low K+ (30 mM) solution (EC50 7.9 x 10(-8); 95% CL, 4.4 x 10(-8)-1.44 x 10(-7) M, n = 6). The results suggested that a major component of SNP-induced relaxation of goat coronary artery was mediated by K(Ca) channels.     

Structural investigation of a water-soluble glucan from an edible mushroom, Astraeus hygrometricus

A water-soluble glucan, Fraction I, was isolated from the aqueous extract of the fruit bodies of the mushroom Astraeus hygrometricus. On the basis of total hydrolysis, methylation analysis, periodate oxidation, and NMR studies ((1)H, (13)C, 2D-COSY, TOCSY, NOESY, and HSQC), the structure of the repeating unit of the glucan is determined as:This glucan shows strong splenocyte activation.     

Swertia (Gentianaceae): chemical and pharmacological aspects

A compilation of the constituents isolated from Swertia species covering the literature up to December 2003 is presented. The botanical classification and ethno-pharmacology of Swertia plants, as well as the biological activities and pharmacological applications of both distinct phytochemicals and medicinally active plant materials (formulations, extracts, etc.) are discussed in detail.     

Chiral symmetry-breaking transition in growth front of crystal phase of 1,1'-binaphthyl in its supercooled melt

Although the theory of spontaneous chiral symmetry-breaking in open systems was proposed some time ago, experimental realization of this phenomenon has not been achieved. In this article, we note that the crystal growth front of 1,1'-binaphthyl shows many of the characteristics of an open system in which chiral symmetry-breaking has occurred. We studied the temperature profiles of the crystallizing surface and obtained X-ray diffraction data of the crystals grown from the melt under controlled conditions. The data show that, under appropriate conditions, the observed bimodal probability distribution of enantiomeric excess (ee) with maxima approximately 60% is due exclusively to chiral crystals and not due to racemic crystals of 1,1'-binaphthyl that can also form at large supercooling. The mass independence of the ee shows that the growing front maintains a constant ee, which is a clear signature of open systems in steady state. Chirality 16:131-136, 2004.     

Epiphytic pink-pigmented methylotrophic bacteria enhance germination and seedling growth of wheat (Triticum aestivum) by producing phytohormone

Methylotrophic bacteria were isolated from the phyllosphere of different crop plants such as sugarcane, pigeonpea, mustard, potato and radish. The methylotrophic isolates were differentiated based on growth characteristics and colony morphology on methanol supplemented ammonium mineral salts medium. Amplification of the mxaF gene helped in the identification of the methylotrophic isolates as belonging to the genus Methylobacterium. Cell-free culture filtrates of these strains enhanced seed germination of wheat (Triticum aestivum) with highest values of 98.3% observed using Methylobacterium sp. (NC4). Highest values of seedling length and vigour were recorded with Methylobacterium sp. (NC28). HPLC analysis of production by bacterial strains ranged from 1.09 to 9.89 μg ml⁻¹ of cytokinins in the culture filtrate. Such cytokinin producing beneficial methylotrophs can be useful in developing bio-inoculants through co-inoculation of pink-pigmented facultative methylotrophs with other compatible bacterial strains, for improving plant growth and productivity, in an environment-friendly manner.     

A novel thermostable xylanase of Paenibacillus macerans IIPSP3 isolated from the termite gut

Xylanase is an enzyme in high demand for various industrial applications, such as those in the biofuel and pulp and paper fields. In this study, xylanase-producing microbes were isolated from the gut of the wood-feeding termite at 50°C. The isolated microbe produced thermostable xylanase that was active over a broad range of temperatures (40-90°C) and pH (3.5-9.5), with optimum activity (4,170 ± 23.5 U mg?1) at 60°C and pH 4.5. The enzyme was purified using a strong cation exchanger and gel filtration chromatography, revealing that the protein has a molecular mass of 205 kDa and calculated pI of 5.38. The half-life of xylanase was 6 h at 60°C and 2 h at 90°C. The isolated thermostable xylanase differed from other xylanases reported to date in terms of size, structure, and mode of action. The novelty of this enzyme lies in its high specific activity and stability at broad ranges of temperature and pH. These properties suggest that this enzyme could be utilized in bioethanol production as well as in the paper and pulp industry.     

Exploration and characterization of agriculturally and industrially important haloalkaliphilic bacteria from environmental samples of hypersaline Sambhar lake, India

Screening of bacteria from Sambhar lake, an extreme hypersaline environment of India, led to the isolation of 93 haloalkaliphilic bacteria growing optimally in media with 2?C25?% salt and 6?C12 pH. Based on 16S rRNA gene sequences, 93 isolates were further categorized into 32 groups, with each group representing a different taxa belonging to 3 phyla (Firmicutes, Proteobacteria and Actinobacteria). Majority of the isolates (53.12?%) showed similarity with phylum Firmicutes which was followed by Proteobacteria (40.63?%) and Actinobacteria (6.25?%). The isolates belonging to 32 representative groups were further evaluated for the production of extracellular enzymes viz. amylase, cellulase, protease and xylanase, plant growth promoting attributes and BIOLOG? substrate usage. Among all the isolates, xylanase producing isolates were in maximum (68?%) as compared to protease (56?%), cellulase (40?%), and amylase (37?%) producing strains. Similarly, among plant growth promoting activities, ammonia producing isolates were highest (56?%) when compared to those producing ACC deaminase (53?%), IAA (50?%), hydrogen cyanide (28?%), siderophore (21?%) and solubilizing P (34?%). Isolates showing enzymatic and PGP activities could be further utilized for promoting plant growth in saline affected area.     

Generation of mesenchymal stem cell lines from murine bone marrow

Mesenchymal stem cells (MSC), because of their multipotency and ease of purification and amplification, are an ideal stem cell source for cell therapies. Bone-marrow-derived stem cells (BMSC) can be used to develop MSC-like immortalized cell lines with large proliferation and differentiation potentialities. Their immortalized status prevents the maintenance of MSC function and characters; this can be negated by modifying the isolation and maintenance protocol. Adult murine BMSC were isolated and maintained in media without additional growth factors together with passage-dependent reseeding following trypsinization. Cells maintained over 25 passages were considered as putative cell lines and characterized. The phenotypic and genotypic characteristics and multilineage differentiation potential of the cells were assessed by morphological, phenotypic, and molecular assays at various passages. The putative BMSC cell lines showed the characteristics of MSC and were able to maintain these characteristics, even after immortalization. The phenotypic data demonstrated difference among two cell lines; this was further validated by the difference in their multilineage differentiation potential following specific induction. More importantly, no changes were observed in the genotypic level in comparison with control cells, even after more than 50 passages. Our protocol thus advances the isolation and maintenance of BMSC and the development of putative BMSC cell lines that maintain characteristics of MSC, including multilineage differentiation potential, after more than 40 passages.