Environmental and spatial characterisation of an unknown fauna using DNA sequencing – an example with Himalayan Hydropsychidae (Insecta: Trichoptera)

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Bioaccumulation of mercury,arsenic, cadmium,and lead in plants grown on coal mine soil

Mercury (Hg), arsenic (As), cadmium (Cd), and lead (Pb) are the major toxic metals released by coal mining activities in the surrounding environment. These metals get accumulated in the soils. The plants grown on the contaminated soil uptake these toxic metals in their roots and aerial parts. This study monitored the bioaccumulation of Hg and other three toxic metals in coal mine soil. The pot study of Hg accumulation in Brassica juncea showed that the extent of Hg uptake by roots and shoots of the plants grown on was high in the mature plant and Hg content in root was higher than the shoot. In the soil of unreclaimed overburden (OB) dump, the toxic metal content was higher than that of reclaimed OB dump which posed high ecological risk in the soil of unreclaimed OB dump. Bioaccumulation coefficient (BAC) value showed that Hg was not accumulated in the leaves of Dalbergia sissoo L., Gmelina arborea, Peltaphorum inerme L., Cassia seamea L, and Acacia mangium L grown on coal mine soil.     

Gonadotropin-releasing hormone alters the T helper cytokine balance in the pregnant rat

The interactions between immune-endocrine and reproductive systems are heightened during pregnancy as an adaptive mechanism, and are regulated by a complex array of hormones and cytokines that control the survival of a semiallogeneic conceptus. GnRH can exert direct effects on the immune system via its receptor (GnRH-R) on lymphoid cells. In the present study, we employed in vitro, ex vivo, and in vivo approaches to investigate the role of GnRH in the modulation of T helper cytokines in pregnant rats undergoing termination of pregnancy. Day 8 pregnant rats were infused with a GnRH agonist (GnRH-Ag) for 24 h using an osmotic minipump. Sham control rats were infused with the vehicle, saline. Lymphocytes were isolated from sham and treated rats and polyclonally stimulated with immobilized anti-CD3 antibody. The levels of the signature T helper 1 (Th-1) cytokines (interferon-gamma [IFN-gamma] and interleukin-2 [IL-2]) and Th-2 cytokines (IL-4 and IL-10) were measured in culture supernatants. Using immunoflourescence confocal microscopy, we demonstrated for the first time the spatial localization of GnRH-R protein on the surface of lymphocytes. We observed a marked increase in IFN-gamma and inhibition of IL-4 production from lymphocytes of pregnant rats treated in vitro with different doses of GnRH-Ag. Further, the responsiveness of lymphocytes to produce IFN-gamma was markedly increased in cells cultured ex vivo from GnRH-Ag infused rats, whereas the capacity of lymphocytes to produce IL-4 was significantly inhibited. In addition, GnRH-Ag infusion in pregnant rats induced a shift toward Th-1 cytokines in the serum. We did not observe any significant difference in IL-2 and IL-10 production in response to GnRH-Ag. Our results suggest an additional function for GnRH as a Th-1 inducer and Th-2 inhibitor. GnRH can thus skew the cytokine balance to predominantly Th-1 type in pregnancy, leading to the termination of pregnancy in rats.     

Sphingolipid storage induces accumulation of intracellular cholesterol by stimulating SREBP-1 cleavage

We showed previously that the intracellular transport of sphingolipids (SLs) is altered in SL storage disease fibroblasts, due in part to the secondary accumulation of free cholesterol. In the present study we examined the mechanism of cholesterol elevation in normal human skin fibroblasts induced by treatment with SLs. When cells were incubated with various natural SLs for 44 h, cholesterol levels increased 25-35%, and cholesterol esterification was reduced. Catabolism of the exogenous SLs was not required for elevation of cholesterol because (i) a non-hydrolyzable and a degradable SL analog elevated cellular cholesterol to similar extents, and (ii) incubation of cells with various SL catabolites, including ceramide, had no effect on cholesterol levels. Elevated cholesterol was derived primarily from low density lipoproteins (LDL) and resulted from up-regulation of LDL receptors induced by cleavage of the sterol regulatory element-binding protein-1. Upon SL treatment, cholesterol accumulated with exogenous SLs in late endosomes and lysosomes. These results suggest a model in which excess SLs present in endocytic compartments serve as a "molecular trap" for cholesterol, leading to a reduction in cholesterol at the endoplasmic reticulum, induction of sterol regulatory element-binding protein-1 cleavage, and up-regulation of LDL receptors.     

Oxidative stress during vitamin A-induced abnormal tail regeneration in the tadpoles of Polypedates maculatus

Vitamin A and its derivatives inhibit normal tail regeneration in amphibians. The most remarkable effect is the development of limbs at the cut end of the tail in anurans. Prior to ectopic limb development, there is an abnormal tail regeneration in the treated tadpoles. The purpose of the present study was to compare oxidative stress condition in the regenerated tail of normal and vitamin A (10I U/ml, 72 h) treated tadpoles. The present findings show a hyper-oxidative stress condition in the regenerated tail of the vitamin A-treated tadpoles of the Indian jumping frog, Polypedates maculatus (Anura: Rhacophoridae).     

Historical mortality in massive<Emphasis Type="Italic"> Porites</Emphasis> from the central Great Barrier Reef,Australia: evidence for past environmental stress?

>Two hiatuses in coral skeleton growth, associated tissue death and subsequent regrowth, were discovered while dating eight multi-century Porites coral cores collected from the central Great Barrier Reef (GBR), Australia. Cross-dating of characteristic annual luminescent lines visible in the coral core slices under UV-light (Hendy et al. 2003) accurately dated the two events to 1782–85 and 1817 a.d.. Die-off scars were observed in only one core for each event. X-radiographs and photographs taken under UV-light show the pattern of regrowth and the period taken by the coral to recover. Bioerosion, predominately by boring sponges ( Cliona spp.), of the exposed coral surface following the 1782–85 event caused a hiatus of up to 14 years' growth, with the coral taking 7–8 years to reclaim the whole surface contained within the 9-cm-diameter core. Contemporary historical and proxy-climate records indicate that El Niño climatic conditions occurred at the time of both growth discontinuities. Intense luminescence observed in corals growing continuously during the 1817 event suggests that low salinity from river runoff was a contributing factor, analogous environmental conditions to those that were associated with the 1998 bleaching event in the GBR.     

Identification,purification and characterization of a receptor for dengue virus-induced macrophage cytotoxin (CF2) from murine T cells

Dengue type-2 virus infection in mice induces a subpopulation of T lymphocytes to produce a cytokine cytotoxic factor, which induces macrophages (Mphi) to produce a biologically active cytotoxic cytokine, the Mphi cytotoxin (CF2). Previously we have identified the presence of intermediate-affinity receptors for CF2 on mouse peritoneal Mphi. The present study was undertaken to identify the CF2-receptors (CF2-R) on murine T cells followed by their purification and characterization. Receptor binding assay and Scatchard analysis revealed single, high-affinity (1.0309 nM) receptors for CF2 on T cells (22000 receptors per cell). The binding of [125I]CF2 on murine T cells was saturable and specific. Furthermore, CF2-R was purified from normal mouse T cell plasma membrane by affinity chromatography followed by reversed-phase high-pressure liquid chromatography. The presence of CF2-R was confirmed by indirect dot-blot assay and its binding with [125I]CF2. The purified CF2-R is a 90-95-kDa protein as characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analysis. The chemical crosslinking of [125I]CF2 and its receptor complex showed a product of 100-110 kDa on different subpopulations of murine T cells. The pretreatment of target cells with anti-CF2-R antisera inhibited the cytotoxic activity of CF2 in a dose-dependent manner and thus confirmed the biological significance of CF2-R. Moreover, the presence of CF2-R was also identified on normal human peripheral blood mononuclear cells and T and B cells by crosslinking with [125I]CF2, thus revealing the possible role of CF2 and CF2-R in the immunopathogenesis of dengue virus disease.     

Intermediate conformation between native β-sheet and non-native α-helix is a precursor of trifluoroethanol-induced aggregation of Human Carbonic Anhydrase-II

In the present work, we examined the correlation between 2,2,2-trifluoroethanol (TFE)-induced conformational transitions of human carbonic anhydrase II (HCAII) and its aggregation propensity. Circular dichroism data indicates that protein undergoes a transition from β-sheet to α-helix on addition of TFE. The protein was found to aggregate maximally at moderate concentration of TFE at which it exists somewhere between β-sheet and α-helix, probably in extended non-native β-sheet conformation. Thioflavin-T (ThT) and Congo-Red (CR) assays along with fluorescence microscopy and transmission electron microscopy (TEM) data suggest that the protein aggregates induced by TFE possess amyloid-like features. Anilino-8-naphthalene sulfonate (ANS) binding studies reveal that the exposure of hydrophobic surface(s) was maximum in intermediate conformation. Our study suggests that the exposed hydrophobic surface and/or the disruption of the structural features protecting a β-sheet protein might be the major reason(s) for the high aggregation propensity of non-native intermediate conformation of HCAII.