Effects of vanadium and tungsten on the nitrogen-fixing cyanobacterium Nostoc linckia

The effects of vanadium and tungsten on growth of the heterocystous cyanobacterium Nostoc linckia (Roth.) Born. and the activity of its nitrogenase and nitrate reductase were studied. While vanadate stimulated the growth of molybdate-limited cells and also their acetylene-reducing ability, it did not stimulate nitrate reductase activity. Tungstate inhibited growth in molybdate-limited cells and also their acetylene reducing and nitrate reductase activities. Acetylene reduction response of cells grown in a tungstate-containing medium indicated certain difference between the modes of action of vanadium and molybdenum. Tungstate caused a slight increase in heterocyst frequency both in nitrogen-fixing and nitrate-grown material. Cyanophycin granules and polyhedral bodies disappeared in molybdate-deficient cells in which thick deposition of polyglucan-like granules occurred throughout the breakdown of cytoplasm and the thylakoids

Effect of shear force on the separation of double stranded DNA

Using the Langevin Dynamics simulation, we have studied the effects of the shear force on the rupture of short double stranded DNA at different temperatures. We show that the rupture force increases linearly with the chain length and approaches to the asymptotic value in accordance with the experiment. The qualitative nature of these curves almost remains same for different temperatures but with a shift in the force. We observe three different regimes in the extension of covalent bonds (back bone) under the shear force.Comment: 4 pages, 4 figure

Spatial variation of the aftershock activity across the Kachchh Rift Basin and its seismotectonic implications

We analyzed 3365 relocated aftershocks with magnitude of completeness (Mc) ≥1.7 that occurred in the Kachchh Rift Basin (KRB) between August 2006 and December 2010. The analysis of the new aftershock catalogue has led to improved understanding of the subsurface structure and of the aftershock behaviour. We characterized aftershock behaviour in terms of a-value, b-value, spatial fractal dimension (D s ), and slip ratio (ratio of the slip that occurred on the primary fault and that of the total slip). The estimated b-value is 1.05, which indicates that the earthquake occurred due to active tectonics in the region. The three dimensional b-value mapping shows that a high b-value region is sandwiched around the 2001 Bhuj mainshock hypocenter at depths of 20–25 km between two low b-value zones above and below this depth range. The D s -value was estimated from the double-logarithmic plot of the correlation integral and distance between hypocenters, and is found to be 2.64 ± 0.01, which indicates random spatial distribution beneath the source zone in a two-dimensional plane associated with fluid-filled fractures. A slip ratio of about 0.23 reveals that more slip occurred on secondary fault systems in and around the 2001 Bhuj earhquake (Mw 7.6) source zone in KRB

Statistical Mechanics of DNA Rupture: Theory and Simulations

We study the effects of the shear force on the rupture mechanism on a double stranded DNA. Motivated by recent experiments, we perform the atomistic simulations with explicit solvent to obtain the distributions of extension in hydrogen and covalent bonds below the rupture force. We obtain a significant difference between the atomistic simulations and the existing results in the iterature based on the coarse-grained models (theory and simulations). We discuss the possible reasons and improve the coarse-grained model by incorporating the consequences of semi-microscopic details of the nucleotides in its description. The distributions obtained by the modified model (simulations and theoretical) are qualitatively similar to the one obtained using atomistic simulations.Comment: 18 pages, 9 figures. Accepted in J. Chem. Phys. (2013). arXiv admin note: text overlap with arXiv:1104.305

Effects of some carbon sources on growth and nitrogen fixation in the cyanobacterium Nostoc linckia

Glucose, fructose, sucrose, maltose, and lactose stimulated photoheterotrophic growth of Nostoc linckia (Roth.)Born. as well as its heterocyst frequency, chlorophyll and protein contents, ammoniacal nitrogen uptake and nitrogenase activities. Glucose, fructose and sucrose also supported slow chemoheterotrophic growth. α-ketoglutarate, pyruvate, ribose, succinate, acetate, sorbose and formate were inhibitory

Does a surface attached globule phase exist ?

A long flexible neutral polymer chain immersed in a poor solvent and interacting with an impenetrable attractive surface exhibits a phase known as surface attached globule ({\bf SAG}) in addition to other adsorbed and desorbed phases. In the thermodynamic limit, the {\bf SAG} phase has the same free energy per monomer as the globular phase, and the transition between them is a surface transition. We have investigated the phase diagrams of such a chain in both two- and three- dimensions and calculated the distribution of monomers in different domains of the phase diagram.Comment: 7 pages, 7 postscript figure

Genetic variability studies for yield and its contributing traits in okra [Abelmoschus esculentus (L.) Moench]

The experiment comprising 30 okra (Abelmoschus esculentus) genotypes were grown and analysed for yield and its attributing traits at the Department of Vegetable science, Kumarganj, Faizabad during Zaid (2011) period. All the characters studied showed a wide range of variation. The variability for yield among the accessionsevaluated was also remarkable. The magnitude phenotypic coefficient of variation was higher than genotypic coefficient of variation for all traits. Both phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) were high for plant height (11.10 and 10.60, respectively). Fruit weight exhibited low value of GCV (2.31) and PCV (4.74) and likely to show less response under selection. High heritability (91.3) with high genetic advance (26.74) was recorded for plant height, whereas, ridges per fruit had high heritability (97.0) with moderate genetic advance (18.45). This study aimed to evaluate okra genotypes for variability with a view to providing information on the development of high yielding genotypes to meet the growing food demand of the populace