Structural property, molecular regulation, and functional diversity of glutamine synthetase in higher plants: a data-mining bioinformatics approach.

Glutamine synthetase (GS; E.C.6.3.1.2) is a key enzyme in higher plants with two isozymes, cytosolic GS1 and plastidic GS2, and involves in the assimilation and recycling of NH4+ ions and maintenance of complex traits such as crop nitrogen-use efficiency and yield. Our present understanding of crop nitrogen-use efficiency and its correlation with the functional role of the GS family genes is inadequate, which delays harnessing the benefit of this key enzyme in crop improvement. In this report, we performed a comprehensive investigation on the phylogenetic relationship, structural properties, complex multilevel gene regulation, and expression patterns of the GS genes to enrich present understanding about the enzyme. Our Gene Ontology and protein-protein interactions analysis revealed the functional aspects of GS isozymes in stress mitigation, aging, nucleotide biosynthesis/transport, DNA repair and response to metals. The insight gained here contributes to the future research strategies in developing climate-smart crops for global sustainability.

Interrelationship between physico-chemical characteristics of a tropical lake and their impact on biodiversity of planktons.

The physicochemical parameters including temperature, pH, dissolved O2, free CO2, total alkalinity, permanent hardness, salinity, transparency, specific conductivity, BOD, COD, phosphate and nitrate were studied in a tropical lake, called Bonhooghly Lake (situated at Baranagar, Kolkata) around the year 2014 and the correlation between the said parameters, as well as their impact on Biodiversity indices were made. There is stable increase of CO2 content in water from August (27.24 mg l-1) and afterwards due to decaying of plant materials. Therefore there is a slight fall of pH (7.1). Significant negative correlation (p<0.01) between pH and CO2 content was also obtained. It also shows a significant negative correlation with O2 content as well. During February and March transparency of water falls significantly with the increase of algal bloom. It significantly decreases dissolved O2 content and pH but increases free dissolved CO2 (p<0.01). Phosphate has a definite correlation with nitrate content of the Lake, possibly because both are among the most essential nutrients of living system. Increase of one obviously indicates escalation of other. During the early months of the year phosphate and nitrate content of water increased steadily (up to 0.13 and 1.85 mg l-1 respectively) and a very high number of Chlamydomonas(up to15100 l-1) and Chlorella (up to 13140 l-1)were observed. Species richness indices (Menhinick's index) of Phytoplanktons were observed maximum in the month of May, dominance (Simpson's index) in January and diversity (Shannon-Weaver index) in April. Zooplanktons also followed the same trend indicating close interdependence. It was significant that apart from other factors, temperature played a most pivotal role in bringing the diversity in the plankton community.

Effect of mercury and methyl parathion on the ovaries of Labeo rohita (Ham).

Adult pre-spawning fish Labeo rohita were sublethally (1/5th 96h LC50) exposed to mercuric chloride and metacid-50 (methyl parathion). Accumulation of mercury and methyl parathion was studied and it was found that pre-spawning ovary appears as a potent organ for deposition of both the pollutants. RNA/DNA ratio of the control and treated fish were studied. It was found that the signifcant decrease in RNA/DNA ratio occurs after 9 and 30 days of exposure for mercury and 30 days for methyl parathion. Fluorescence microscopic studies by acridine orange staining method were also performed to show how much it is related to biochemical alterations. In some cases loss of metachromasia is correlated with the fall in RNA/DNA ratio. Some other abnormalities like fall in stage II: stage I oocyte ratio and necrosis was also observed.