Vibrational dynamics and heat capacity of polyglycine I

Earlier works on polyglycine I suffer from several infirmities, such as the dynamic methylene group being replaced by a mass unit and the use of poorly resolved inelastic neutron spectra, which have resulted in wrong assignments and imprecise profile of dispersion curves. In addition, the density-of-states and heat capacity variation as a function of temperature are being reported for the first time. The heat capacity is in good agreement with the measurements reported earlier by Roles and Wunderlich within a certain range (230-350 K). Deviations set in beyond this could be due to the presence of two crystalline states (I and II) in the sample used for the heat capacity measurements.     

Sequence analysis of the long arm of rice chromosome 11 for rice–wheat synteny

The DNA sequence of 106 BAC/PAC clones in the minimum tiling path (MTP) of the long arm of rice chromosome 11, between map positions 57.3 and 116.2 cM, has been assembled to phase 2 or PLN level. This region has been sequenced to 10× redundancy by the Indian Initiative for Rice Genome Sequencing (IIRGS) and is now publicly available in GenBank. The region, excluding overlaps, has been predicted to contain 2,932 genes using different software. A gene-by-gene BLASTN search of the NCBI wheat EST database of over 420,000 cDNA sequences revealed that 1,143 of the predicted rice genes (38.9%) have significant homology to wheat ESTs (bit score 100). Further BLASTN search of these 1,143 rice genes with the GrainGenes database of sequence contigs containing bin-mapped wheat ESTs allowed 113 of the genes to be placed in bins located on wheat chromosomes of different homoeologous groups. The largest number of genes, about one-third, mapped to the homoeologous group 4 chromosomes of wheat, suggesting a common evolutionary origin. The remaining genes were located on wheat chromosomes of different groups with significantly higher numbers for groups 3 and 5. Location of bin-mapped wheat contigs to chromosomes of all the seven homoeologous groups can be ascribed to movement of genes (transpositions) or chromosome segments (translocations) within rice or the hexaploid wheat genomes. Alternatively, it could be due to ancient duplications in the common ancestral genome of wheat and rice followed by selective elimination of genes in the wheat and rice genomes. While there exists definite conservation of gene sequences and the ancestral chromosomal identity between rice and wheat, there is no obvious conservation of the gene order at this level of resolution. Lack of extensive colinearity between rice and wheat genomes suggests that there have been many insertions, deletions, duplications and translocations that make the synteny comparisons much more complicated than earlier thought. However, enhanced resolution of comparative sequence analysis may reveal smaller conserved regions of colinearity, which will facilitate selection of markers for saturation mapping and sequencing of the gene-rich regions of the wheat genome.     

Biodegradation of 4-aminobenzenesulphonate by a newly isolated bacterial strain PNS-1

A bacterial strain PNS-1, isolated from activated sludge derived from a domestic wastewater treatment unit, could utilize 4-aminobenzenesulphonate (4-ABS) as a sole organic carbon and energy source under aerobic conditions. Degradation rate varied with the initial concentration of 4-ABS and maximum specific substrate removal rate was observed at 400mg 4-ABS l^–1 (2.3mM). Average biomass yield was 0.31mg/mg 4-ABS degraded. Biokinetic parameters for the degradation, determined using the Haldane relationship, were 0.26h^–1 (_max), 6mg\,l^–1 (K_S) and 4020mg\,l^–1 (K_i). Strain PNS-1 could not utilize other isomers of benzenesulphonate and 5-sulphosalicylate as growth substrates whereas protocatechuate, pyrocatechuate and p-hydroxybenzoate could be degraded. In mixed substrate batch cultivations, where 4-ABS was one of the component, protocatechuate and 4-ABS were simultaneously utilized. Presence of 2- or 3-ABS decreased the growth and substrate degradation rates of 4-ABS. With 4-ABS and pyrocatechuate, although a lag phase was observed prior to pyrocatechuate degradation, a diauxic growth pattern was not seen.     

Interaction of human pancreatic ribonuclease with human ribonuclease inhibitor. Generation of inhibitor-resistant cytotoxic variants

Mammalian ribonucleases interact very strongly with the intracellular ribonuclease inhibitor (RI). Eukaryotic cells exposed to mammalian ribonucleases are protected from their cytotoxic action by the intracellular inhibition of ribonucleases by RI. Human pancreatic ribonuclease (HPR) is structurally and functionally very similar to bovine RNase A and interacts with human RI with a high affinity. In the current study, we have investigated the involvement of Lys-7, Gln-11, Asn-71, Asn-88, Gly-89, Ser-90, and Glu-111 in HPR in its interaction with human ribonuclease inhibitor. These contact residues were mutated either individually or in combination to generate mutants K7A, Q11A, N71A, E111A, N88R, G89R, S90R, K7A/E111A, Q11A/E111A, N71A/E111A, K7A/N71A/E111A, Q11A/N71A/E111A, and K7A/Q11A/N71A/E111A. Out of these, eight mutants, K7A, Q11A, N71A, S90R, E111A, Q11A/E111A, N71A/E111A, and K7A/N71A/E111A, showed an ability to evade RI more than the wild type HPR, with the triple mutant K7A/N71A/E111A having the maximum RI resistance. As a result, these variants exhibited higher cytotoxic activity than wild type HPR. The mutation of Gly-89 in HPR produced no change in the sensitivity of HPR for RI, whereas it has been reported that mutating the equivalent residue Gly-88 in RNase A yielded a variant with increased RI resistance and cytotoxicity. Hence, despite its considerable homology with RNase A, HPR shows differences in its interaction with RI. We demonstrate that interaction between human pancreatic ribonuclease and RI can be disrupted by mutating residues that are involved in HPR-RI binding. The inhibitor-resistant cytotoxic HPR mutants should be useful in developing therapeutic molecules.     

Concurrent sorption of Ni2+ and Cu2+ by Chlorella vulgaris from a binary metal solution

Kinetics and capacity of Ni2+ and Cu2+ sorption by Chlorella vulgaris were studied using single and binary metal solutions at various concentrations of these metal ions. The second-order rate law best described the kinetics of metal sorption from both single and binary metal systems. C. vulgaris preferentially sorbed Cu2+ over Ni2+ in the binary system. In comparison to the single metal system, the amounts of Ni2+ and Cu2+ sorbed at equilibrium (qe) were respectively 73% and 25%, and the initial rate of sorption (h) was ca. 50% in the case of the binary metal system. The test metals inhibited sorption of each other, thereby indicating competition between Ni2+ and Cu2+ for sorption onto non-specific binding sites. The present study showed that C. vulgaris has specific as well as non-specific sites for the binding of Ni2+ and Cu2+. Participation of these sites for sorption depended on the ratio of Ni2+ and CU2+ in solution. The maximum metal sorption capacity of C. vulgaris was 6.75 mmol g(-1) from the binary metal solution at the tested biomass concentration (100 mg dry weight l(-1)). Total metal sorption was enhanced with increasing total concentration of both the metals up to 1.6 mM, beyond which a decrease occurred. Two-dimensional contour plots were successfully used for the first time for the evaluation of metal sorption potential.     

Genome Sequence of Microbacterium yannicii, a Bacterium Isolated from a Cystic Fibrosis Patient

Microbacterium yannicii is a Gram-positive, aerobic, yellow-pigmented, rod-shaped, nonmotile, oxidase-negative, and catalase-positive bacterium isolated on Columbia colistin-nalidixic acid (CNA) agar with 5% sheep blood from the sputum of a cystic fibrosis patient. The present study reports the draft genome of a Microbacterium yannicii strain.     

Decolorization of a recalcitrant organic compound (Melanoidin) by a novel thermotolerant yeast, Candida tropicalis RG-9

ABSTRACT: BACKGROUND: Sugarcane distilleries use molasses for ethanol production and generate large volume ofeffluent containing high biological oxygen demand (BOD) and chemical oxygen demand(COD) along with melanoidin pigment. Melanoidin is a recalcitrant compound that causesseveral toxic effects on living system, therefore, may be treated before disposal. The aim ofthis study was to isolate a potential thermotolerant melanoidin decolorizing yeast fromnatural resources, and optimized different physico-chemical and nutritional parameters. RESULTS: Total 24 yeasts were isolated from the soil samples of near by distillery site, in which isolateY-9 showed maximum decolorization and identified as Candida tropicalis by Microbial TypeCulture Collection (MTCC) Chandigarh, India. The decolorization yield was expressed as thedecrease in the absorbance at 475 nm against initial absorbance at the same wavelength.Uninoculated medium served as control. Yeast showed maximum decolorization (75%) at 45°C using 0.2%, glucose; 0.2%, peptone; 0.05%, MgSO4; 0.01%, KH2PO4; pH-5.5 within 24 hof incubation under static condition. Decolorizing ability of yeast was also confirmed by highperformance liquid chromatography (HPLC) analysis. CONCLUSION: The yeast strain efficiently decolorized melanoidin pigment of distillery effluent at highertemperature than the other earlier reported strains of yeast, therefore, this strain could also beused at industrial level for melanoidin decolorization as it tolerated a wide range oftemperature and pH with very small amount of carbon and nitrogen sources.