Aggregates Characterization and Its Associated Organic Carbon in Two Contrasting Lowland Rice Soils of West Bengal

Aims: The present study investigated the effect of lowland rice soils of two regions viz. new alluvial and red-laterite on aggregate characterization and their associated organic carbon (SOC). Study Design: Randomized block design (RBD). Place and Duration of Study: New alluvial soils were collected from Jangipara block of Hooghly, West Bengal and Red-laterite soils were collected from Raghunathpur block of Purulia, West Bengal during 2017-18. Methodology: For each soil types (New alluvial and Red-laterite) five locations were identified and soil samples were collected from three depths i.e. 0-10, 10-20 and 20-30 cm. The aggregate characteristics i.e. water-stable aggregates (WSAs), mean weight diameter (MWD), aggregate stability and aggregate size fractions along with the distribution of carbon in those aggregate size fractions were critically studied. Results: The aggregate size as well as the stability decreased with increasing soil depth from 0 to 30 cm in both soils. New alluvial soils showed higher aggregate stability than red-laterite soils. Mean weight diameter (MWD) values of new alluvial soils were 34, 29 and 87% more than red-laterite soils at 0-10, 10-20 and 20-30 cm depth, respectively. Presence of higher amount of clay and organic matter in new alluvial made the difference in structural coefficient. The surface soil (0-10 cm) had more coarse aggregate (Cmac A >2000μ) fraction, however, microaggregates (<250μ) were dominant in lower depths in both soils. Water stable aggregates (WSA) in surface soils of new alluvial and red-laterite were 57 and 36%, respectively and were decreased with depth. Red-laterite produced higher micro aggregates as compared to new alluvial soils. Coarse macro aggregate fractions (>2000μ) retained maximum amount of soil organic carbon in both soils however, coarse micro aggregate associated carbon (Cmic AC<250μ) was captured in lower depths. New alluvial soils yielded aggregates with higher in diameter and stability coefficient that is due to higher amount of carbon stored in aggregates. Conclusion: The abundance of macro aggregate of New alluvial soils indicates better soil physical quality than Red-laterite soil which was dominated in higher micro aggregates leads to poor in structure and susceptible to water erosion.

Effect of various organic compounds on synthesis of glucoamylase by an isolated strain Penicillium italicum.

Yeast extract (0.5%) stimulates the production of glucoamylase and cell synthesis while methylene blue (0.1 mM) activates the synthesis of glucoamylase. Studies on the metabolic changes during fermentation of glucoamylase in a selected medium by P. italicum show that the rate of production of glucoamylase and cellular growth are greatly accelerated between 48 and 168 hr. Rapid growth of cells during this period may account for enhanced utilization of maltose and NH4NO3 from the medium. The acid production remains constant from 48 to 144 hr. Different forms of nitrogen decrease steadily. Although methylene blue stimulates the production of glucoamylase in the broth it has practically no effect on the rate of utilization of amino and total nitrogen from the broth.

Interaction of berberine chloride with deoxyribonucleic acids: evidence for base and sequence specificity.

The interaction of berberine chloride with natural and synthetic DNAs of differing base composition and sequences was followed by various spectroscopic and viscometric studies. The binding of berberine chloride was characterized by hypochromism and bathochromism in the absorption bands, enhancement of fluorescence intensity, stabilization against thermal denaturation, perturbations in the circular dichroic spectrum, increase in the contour length of sonicated rod-like DNA and induction of unwinding-rewinding process of covalently closed superhelical DNA, depending on the base composition and sequences of base pairs. Binding parameters determined from absorbance and fluorescence titration by Scatchard analysis, according to an excluded-site model, indicated a very high specificity of berberine to AT-rich DNAs and alternate AT polymer. Fluorescence quantum yield was maximum for the complexes with AT-rich DNAs and alternate AT polymer. Taken together, these results suggest that berberine chloride exhibits considerable specificity towards alternating AT polymer and binds to AT-rich DNAs by a mechanism of classical intercalation.