TLR4 and NKT Cell Synergy in Immunotherapy against Visceral Leishmaniasis

NKT cells play an important role in autoimmune diseases, tumor surveillance, and infectious diseases, providing in most cases protection against infection. NKT cells are reactive to CD1d presented glycolipid antigens. They can modulate immune responses by promoting the secretion of type 1, type 2, or immune regulatory cytokines. Pathogen-derived signals to dendritic cells mediated via Toll like Receptors (TLR) can be modulated by activated invariant Natural Killer T (iNKT) cells. The terminal β-(1–4)-galactose residues of glycans can modulate host responsiveness in a T helper type-1 direction via IFN-γ and TLRs. We have attempted to develop a defined immunotherapeutic, based on the cooperative action of a TLR ligand and iNKT cell using a mouse model of visceral leishmaniasis. We evaluated the anti-Leishmania immune responses and the protective efficacy of the β-(1–4)-galactose terminal NKT cell ligand glycosphingophospholipid (GSPL) antigen of L. donovani parasites. Our results suggest that TLR4 can function as an upstream sensor for GSPL and provoke intracellular inflammatory signaling necessary for parasite killing. Treatment with GSPL was able to induce a strong effective T cell response that contributed to effective control of acute parasite burden and led to undetectable parasite persistence in the infected animals. These studies for the first time demonstrate the interactions between a TLR ligand and iNKT cell activation in visceral leishmaniasis immunotherapeutic.     

Vanadium toxicology – an assessment of general health, haematological aspects and energy response in an Indian catfish Clarias batrachus (Linn)

The pervasive occurrence of vanadium in nature and its use in various industrial processes has increased its inputs in the environment. This has prompted us to elucidate the impact of vanadium on aquatic environ-ment, the primary body for industrial effluent discharge. The energy response of the fish, Clarias batra-chus, its haematological status including haemoglobin (Hb), haematocrit (Ht), leutocrit (Lt), mean corpuscular haemoglobin (MCH), mean corpuscular volume (MCV), mean corpuscular haemoglobin concen-tration (MCHC) etc. And overall general health conditions have been observed to be significantly hampered leading to deleterious alterations in the general metabolism of the fish following long term exposure to vana-date. The increase in muscle and tissue lactic acid (2–12 fold) in association with decrease in pyruvic acid (72% in mucle; 26% in liver) reflect a shift towards an anaerobic metabolism of the fish. We conclude that vanadium could be toxic for the fish in question under long term exposure at the doses under observation (2–10 mg L).© Rapid Science 1998     

Interethnic comparisons of three endogamous groups of West Bengal with respect to two sets of variables

The present paper focuses on the interethnic comparison among three endogamous groups (a higher caste, a tribe and a religious group) with different ethnohistorical background. A total of 700 individuals were studied from their anthropometric and dermatoglyphic traits along with their asymmetries. Statistical comparisons were carried out through the use of student’s ‘t’ test and Sanghvi’s T² statistics. Heterogeneity for most of the anthropometric and some dermatoglyphic traits supports their different origins. Though dermatoglyphic asymmetry doesn’t reveal significant discrimination, heterogeneity in anthropometric asymmetry corroborates with their different occupations. The anthropometric distances show greater values than the dermatoglyphic distances. This difference is probably due to the fact that anthropometry is not independent of environment and not a stable character like dermatoglyphic traits.     

Synthesis and characterization of nanocrystalline zinc sulfide via zinc thiobenzoate-lutidine single-source precursor

ZnS nanocrystals were prepared both in the form of mesoporous powder and thin films by one step thermal decomposition technique from a single-source procure (SSP) [Zn(SOCPh)₂Lut₂·H₂O]. The final product was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), N₂ adsorption-desorption isotherm, UV-Vis absorption spectroscopy and photoluminescence (PL) study. Structural analyses of the prepared ZnS revealed the formation of cubic crystallites with diameters around 5 and 10 nm for the thin films and powder materials, respectively. On the other hand, the powder form showed mesoporous nature (type IV isotherm) with an average pore diameter of 37.9 Å and BET specific surface area of 51.73 m²/g.     

Study of antimicrobial activity and root symbionts of Hemionitis arifolia

Antibacterial and antifungal activity of crude extract, alcoholic extract and extracted phenol from various parts of tropical pteridophyta, Hemionitis arifolia were tested by agar diffusion and tube dilution assay. Both the crude and alcoholic extracts of vegetative and reproductive leaves of H. arifolia showed considerable antibacterial activity against Gram negative test strain of Escherichia coli (MTCC-739). Extract from reproductive leaves also showed moderate antibacterial activity against Bacillus subtilis (MTCC-441) (Gram positive test strain) but didn’t show any antifungal activity against Candida albicans (MTCC-7353). Mycorrhizal and other symbiotic association with the root system of H. arifolia was studied and it is revealed that a number of mycorrhizal strains were present in both vegetative and reproductive form. Presence of Dark Septate Endophytic Fungi (DSF) was also detected.     

Optical features of the fluorophore azotobactin: Applications for iron sensing in biological fluids

Siderophores are bio‐organic ligands secreted by microbes to chelate and assimilate iron to meet their metabolic requirements. Siderophores and their analogs have tremendous therapeutic and analytical potential including the use as Fe (III) biosensors; however, only few practical applications have been realized. The aim of this study was the optical and biophysical characterization of the siderophore azotobactin (Az) secreted by the nitrogen‐fixing bacteria Azotobacter vinelandii. The peptide exhibited fluorescence in the visible range. Quantum yield and lifetime in excited state were measured to ascertain the sensitivity of the molecule as a fluorescent marker in biochemical assays. Its high affinity toward iron in the ferric state was demonstrated through fluorescence emission quenching studies. The accuracy of azotobactin as biosensing tool was determined by analyzing the levels of iron in biological fluids, particularly in human serum. Furthermore, it was demonstrated that it can be encapsulated in sol–gel matrices without significant loss of its fluorescence signal, thus enabling it suitable for adaptation to optical biosensor for Fe (III).     

Polysaccharides from the brown seaweed Padina tetrastromatica: Characterization of a sulfated fucan

Sulfated fucans, the complex polysaccharides from brown seaweeds, possess various biological activities. To understand the structure activity relationship of sulfated fucans, we have investigated the structural features of one such polymer from Padina tetrastromatica using standard methods of carbohydrate structural analysis. We report a novel structural motif for this polymer. The average structure of this macromolecule that has a molecular mass of 25 kDa differs from the previous models in three respects. First, the core region of this macromolecule is composed primarily of α-(1 → 2)- and α-(1 → 3)-linked fucopyranosyl residues. Sulfate groups, when present are located at position 4 and 2 of fucosyl residues. Secondly, fucose and xylose is attached to this polymer to form branch points, one for every two residues within the chain. Finally, this macromolecule contained smaller amount of sulfate (0.21 mol of sulfate per mol of deoxyhexose).     

Understanding ageing effects using complexity analysis of foot–ground clearance during walking

Ageing influences gait patterns which in turn can affect the balance control of human locomotion. Entropy-based regularity and complexity measures have been highly effective in analysing a broad range of physiological signals. Minimum toe clearance (MTC) is an event during the swing phase of the gait cycle and is highly sensitive to the spatial balance control properties of the locomotor system. The aim of this research was to investigate the regularity and complexity of the MTC time series due to healthy ageing and locomotors' disorders. MTC data from 30 healthy young (HY), 27 healthy elderly (HE) and 10 falls risk (FR) elderly subjects with balance problems were analysed. Continuous MTC data were collected and using the first 500 data points, MTC mean, standard deviation (SD) and entropy-based complexity analysis were performed using sample entropy (SampEn) for different window lengths (m) and filtering levels (r). The MTC SampEn values were lower in the FR group compared to the HY and HE groups for all m and r. The HY group had a greater mean SampEn value than both HE and FR reflecting higher complexity in their MTC series. The mean SampEn values of HY and FR groups were found significantly different for m = 2, 4, 5 and r = (0.1–0.9) × SD, (0.3–0.9) × SD and (0.3–0.9) × SD, respectively. They were also significant difference between HE and FR groups for m = 4–5 and r = (0.3–0.7) × SD, but no significant differences were seen between HY and HE groups for any m and r. A significant correlation of SampEn with SD of MTC was revealed for the HY and HE groups only, suggesting that locomotor disorders could significantly change the regularity or the complexity of the MTC series while healthy ageing does not. These results can be usefully applied to the early diagnosis of common gait pathologies.