Virus antibody dynamics in primary and secondary dengue infections

Dengue viral infections show unique infection patterns arising from its four serotypes, (DENV-1,2,3,4). Its effects range from simple fever in primary infections to potentially fatal secondary infections. We analytically and numerically analyse virus dynamics and humoral response in a host during primary and secondary dengue infection for long periods using micro-epidemic models. The models presented here incorporate time delays, antibody dependent enhancement, a dynamic switch and a correlation factor between different DENV serotypes. We find that the viral load goes down to undetectable levels within 7–14 days as is observed for dengue infection, in both cases. For primary infection, the stability analysis of steady states shows interesting dependence on the time delay involved in the production of antibodies from plasma cells. We demonstrate the existence of a critical value for the immune response parameter, beyond which the infection gets completely cured. For secondary infections with a different serotype, the homologous antibody production is enhanced due to the influence of heterologous antibodies. The antibody production is also controlled by the correlation factor, which is a measure of similarities between the different DENV serotypes involved. Our results agree with clinically observed humoral responses for primary and secondary infections.     

GPI-anchored protein organization and dynamics at the cell surface

The surface of eukaryotic cells is a multi-component fluid bilayer in which glycosylphosphatidylinositol (GPI)-anchored proteins are an abundant constituent. In this review, we discuss the complex nature of the organization and dynamics of GPI-anchored proteins at multiple spatial and temporal scales. Different biophysical techniques have been utilized for understanding this organization, including fluorescence correlation spectroscopy, fluorescence recovery after photobleaching, single particle tracking, and a number of super resolution methods. Major insights into the organization and dynamics have also come from exploring the short-range interactions of GPI-anchored proteins by fluorescence (or Förster) resonance energy transfer microscopy. Based on the nanometer to micron scale organization, at the microsecond to the second time scale dynamics, a picture of the membrane bilayer emerges where the lipid bilayer appears inextricably intertwined with the underlying dynamic cytoskeleton. These observations have prompted a revision of the current models of plasma membrane organization, and suggest an active actin-membrane composite.     

Effect of berseem (T. alexandrinum L.) on the growth of maize crop on artificially compacted soil

Summary A pot experiment to evaluate the effect of growing berseem on the growth of maize on soil artificially compacted to different soil bulk densities was conducted during 1964–65 and 1965–66 at the Indian Agricultural Research Institute, New Delhi. The results obtained from the experiment showed that yield of berseem fodder was almost identical in pots with 1.5 and 1.6 g/cm³ soil bulk densities, but decreased abruptly as the bulk densities increased from 1.6 to 1.8 g/cm³. Increase in bulk density of soil from 1.6 to 1.8 g/cm³ adversely affected the growth of maize plants but growing of berseem mitigated the ill-effects of soil compaction. Maize crop grown in pots where berseem was grown, exhibited better growth of roots and shoots and thus produced more dry matter per plant than where no berseem was grown.A part of the Ph.D. Thesis submitted by the senior author, Div. of Agronomy, Indian Agricultural Research Institute, New Delhi, India.Formerly Agronomist, I.A.R.I., New Delhi, Professor of Agronomy, U.P. Agricultural University, Pantnagar, India.     

Degradation of unpretreated and thermally pretreated polypropylene by soil consortia

Unpretreated (PP-UT) and thermally pretreated (at 80 °C for 10 days) polypropylene (PP-TT) films of 0.05 mm thickness were subjected to in vitro biodegradation in minimal medium with mixed soil culture for 12 months. In this period 10.7 and 0.4% weight loss was observed with PP-TT and PP-UT, respectively. The tensile strength decreased by 51.8 and 28.3%, the crystallinity increased by 28 and 33% and isotacticity increased by 3 and 9%, respectively, over the same time period. The ester carbonyl index in PP-TT increased up to 9 months and later decreased indicating abiotic followed by biotic process. No such changes were observed with PP-UT. Methyl group index decreased in both the cases indicating oxidation at the primary carbon. Increase in surface energy indicated that the polymer became hydrophilic. Surface changes were observed by SEM and AFM. A single culture was isolated at the end of 12 months and it was identified as Bacillus flexus. The morphology of the organism was rods in a chain and it was present in the form of an endospore.     

The first draft of the pigeonpea genome sequence

Pigeonpea (Cajanus cajan) is an important grain legume of the Indian subcontinent, South-East Asia and East Africa. More than eighty five percent of the world pigeonpea is produced and consumed in India where it is a key crop for food and nutritional security of the people. Here we present the first draft of the genome sequence of a popular pigeonpea variety ??Asha??. The genome was assembled using long sequence reads of 454 GS-FLX sequencing chemistry with mean read lengths of >550?bp and >10-fold genome coverage, resulting in 510,809,477?bp of high quality sequence. Total 47,004 protein coding genes and 12,511 transposable elements related genes were predicted. We identified 1,213 disease resistance/defense response genes and 152 abiotic stress tolerance genes in the pigeonpea genome that make it a hardy crop. In comparison to soybean, pigeonpea has relatively fewer number of genes for lipid biosynthesis and larger number of genes for cellulose synthesis. The sequence contigs were arranged in to 59,681 scaffolds, which were anchored to eleven chromosomes of pigeonpea with 347 genic-SNP markers of an intra-species reference genetic map. Eleven pigeonpea chromosomes showed low but significant synteny with the twenty chromosomes of soybean. The genome sequence was used to identify large number of hypervariable ??Arhar?? simple sequence repeat (HASSR) markers, 437 of which were experimentally validated for PCR amplification and high rate of polymorphism among pigeonpea varieties. These markers will be useful for fingerprinting and diversity analysis of pigeonpea germplasm and molecular breeding applications. This is the first plant genome sequence completed entirely through a network of Indian institutions led by the Indian Council of Agricultural Research and provides a valuable resource for the pigeonpea variety improvement.     

Modulatory role of Emblica officinalis fruit extract against arsenic induced oxidative stress in Swiss albino mice

Arsenic, an important human toxin, is naturally occurring in groundwater and its accumulation in plants and animals have assumed a menacing proportion in a large part of the world, particularly Asia. Epidemiological studies have shown a strong association between chronic arsenic exposure and various adverse health effects, including cardiovascular diseases, neurological defects and cancer of lung, skin, bladder, liver and kidney. The protective role of the fruits of Emblica officinalis (500 mg/kg b.wt.) was studied in adult Swiss albino mice against arsenic induced hepatopathy. Arsenic treated group (NaAsO₂, 4 mg/kg b.wt.) had a significant increase in serum transaminases and lipid peroxidation (LPO) content in liver, whereas significant decrease was recorded in hepatic superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST) and serum alkaline phosphatase activity. Combined treatment of Emblica and arsenic (pre and post) declined the serum transaminases and LPO content in liver whereas significant increase was noticed in SOD, CAT, GST and serum alkaline phosphatase activities. Liver histopathology showed that Emblica fruit extract had reduced karyolysis, karyorrhexis, necrosis and cytoplasmic vacuolization induced by NaAsO₂ intoxication. Thus it can be concluded that pre- and post-supplementation of E. officinalis fruit extract significantly reduced arsenic induced oxidative stress in liver.