Crystal structure of raw pure Mysore silk fibre based on (Ala-Gly)2-Ser-Gly peptide sequence using Linked-Atom-Least-Squares method

We have carried out crystal structure analysis of raw pure Mysore silk fibers belonging toBombyx mori on the basis of model parameters of Marshet al using Linked-Atom-Least-Squares technique. The intensity of all the reflections were computed employing CCP13 software. We observe that the molecular modification is essentially same as β-pleated structure with antipolar-antiparallel arrangements formed by hydrogen bonds. The essential differences observed in the structure are highlighted and discussed     

A novel barcode system for rapid identification of rice (Oryza sativa L.) varieties using agro-morphological descriptors and molecular markers

Molecular Biology Reports - Rice varietal identification is a crucial aspect in breeding, seed production and trade in order to protect the interests of the farmers and consumers. As the number of...     

Refined molecular and crystal structure of silk I based on Ala-Gly and (Ala-Gly)(2)-Ser-Gly peptide sequence

The molecular and crystal structure of one of the crystalline modifications of Bombyx mori, silk I, was determined by x-ray diffraction method. Cell dimensions are essentially the same as those found in the synthetic model peptide poly(L-Ala-Gly). The (straight phi, psi) values of L-Ala and Gly in the repeating unit are (-112 degrees, -6 degrees ), and (71 degrees, -99 degrees ) respectively, which are in the Bridge and the forth quadrant regions of the Ramachandran map, respectively. The observed molecular conformation in the present study has a "crank-shaft" or a S-shaped zigzag arrangement, leading to a remarkable agreement of observed and calculated structure amplitudes for both dipeptide and hexapeptide sequences, and has a reasonable hydrogen bond networks. Obtained (straight phi, psi) values are quite different from those reported by Lotz and Keith, even though overall appearances are quite similar to each other. In spite of intra- and intermolecular hydrogen-bond networks, silk I structure changes easily to the silk II by a mechanical deformation. This fragility may be due to the above peculiar crank-shaft conformation deduced from the alternating structure of alanine and glycine.     

Cephalosporin-derived inhibitors of beta-lactamase. Part 4: The C3 substituent

New C3-substituted beta-lactamase inhibitors were prepared and evaluated against representative class A and class C enzymes. It was possible to improve simultaneous inhibitory activity of both classes of serine hydrolase. Other inhibitors showed high selectivity for either the class C cephalosporinases or the class A penicillinases. This represents the first time that cephalosporin-derived inhibitors have demonstrated selectivity for the class A beta-lactamases.     

Compliance with bladder protocol during concurrent chemoradiation for cancer of the cervix and its impact on enteritis: A prospective observational study

Aim

This prospective study aims to assess the compliance with bladder protocol and the correlation with enteritis during pelvic radiation.

Survival and competitive ability of ammonia excreting and nonammonia excretingAzotobacter chroococcum strains in sterile soil

Summary The survival of two multiple antibiotic resistant native isolates ofAzotobacter chroococcum (A10 and A42), one of them (A10) having high nitrogenase activity and high ammonia excreting ability and another (A42) having low nitrogenase activity and low ammonia excreting ability were studied in sterile sandy loam soil with amendments of compost and glucose and without amendments. The decrease in cell numbers over a period of four weeks in all the three types of treatments approximated 4 log units. However, the death rate was more in the first two weeks. In all the treatments A10 showed better survival and competitive ability than A42 both singly and in mixed culture.     

Effect of culture conditions on lipid and gamma-linolenic acid production by mucoraceous fungi

The effect of various culture conditions on growth, lipid production and fatty acid composition in Mucor rouxii and Mucor sp.1b were studied. Total lipid production was higher in media containing potassium nitrate for both the cultures (30%) and cultures grown on plant seed oil produced more than 44% lipid. Among the carbon sources tested, γ-linolenic acid (GLA) production was maximal in cultures grown on glucose. The major fatty acids produced by these two cultures were palmitic, stearic and oleic acids. Levels of GLA in M. rouxii and M. sp.1b was in the range of 3–17% under different culture conditions. Lactose was a poor promoter for biomass and lipid production in both cultures. No GLA was found in fungal cultures grown on sesame oil. The optimal conditions for the production of GLA was standardised in these cultures.     

Metabolic profiling of lung granuloma in Mycobacterium tuberculosis infected guinea pigs: ex vivo 1H magic angle spinning NMR studies

A crucial and distinctive feature of tuberculosis infection is that Mycobacterium tuberculosis (Mtb) resides in granulomatous lesion at various stages of disease development and necrosis, an aspect that is little understood. We used a novel approach, applying high resolution magic angle spinning nuclear magnetic resonance spectroscopy (HRMAS NMR) directly to infected tissues, allowing us to study the development of tuberculosis granulomas in guinea pigs in an untargeted manner. Significant up-regulation of lactate, alanine, acetate, glutamate, oxidized and the reduced form of glutathione, aspartate, creatine, phosphocholine, glycerophosphocholine, betaine, trimethylamine N-oxide, myo-inositol, scyllo-inositol, and dihydroxyacetone was clearly visualized and was identified as the infection progressed. Concomitantly, phosphatidylcholine was down-regulated. Principal component analysis of NMR data revealed clear group separation between infected and uninfected tissues. These metabolites are suggestive of utilization of alternate energy sources by the infiltrating cells that generate much of the metabolites in the increasingly necrotic and hypoxic developing granuloma through the glycolytic, pentose phosphate, and tricarboxylic acid pathways. The most relevant changes seen are, surprisingly, very similar to metabolic changes seen in cancer during tumor development.     

Laminin is required to orient epithelial polarity in the C. elegans pharynx

The development of many animal organs involves a mesenchymal to epithelial transition, in which cells develop and coordinate polarity through largely unknown mechanisms. The C. elegans pharynx, which is an epithelial tube in which cells polarize around a central lumen, provides a simple system with which to understand the coordination of epithelial polarity. We show that cell fate regulators cause pharyngeal precursor cells to group into a bilaterally symmetric, rectangular array of cells called the double plate. The double plate cells polarize with apical localization of the PAR-3 protein complex, then undergo apical constriction to form a cylindrical cyst. We show that laminin, but not other basement membrane components, orients the polarity of the double plate cells. Our results provide in vivo evidence that laminin has an early role in cell polarity that can be distinguished from its later role in basement membrane integrity.     

A new spectrophotometric method of assay for chitosanase based on calcofluor white dye binding

A new spectrophotometric method for the assay of chitosanase based on complex formation of the substrate chitosan with Calcofluor white dye is described. The absorption maximum for the chitosan-Calcofluor complex is determined to be 406 nm. The apparent minimum size of chitosan for complex formation is 5–7 kDa. Therefore, those enzymes that do not generate glucosamine or reducing groups as products of hydrolysis at levels not measurable by the available methods of assay can be assayed by the present method. In the standardized procedure 200 μg of chitosan in acetate buffer pH 4.5 with the enzyme in a reaction volume of 1.5ml is incubated at 45°C for 1 h, after which 1.5 ml of Calcofluor white (0.05%) is added, kept for 1h and absorbance at 406 nm measured by a spectrophotometer. The chitosanase unit is arbitrarily defined as the reduction in absorbance by 0.01/min.