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.     

Modeling the structure and proton transfer pathways of the mutant His-107-Tyr of human carbonic anhydrase II

We present molecular modeling of the structure and possible proton transfer pathways from the surface of the protein to the zinc-bound water molecule in the active site of the mutant His-107–Tyr of human carbonic anhydrase II (HCAII). No high-resolution structure or crystal structure is available till now for this particular mutant due to its lack of stability at physiological temperature. Our analysis utilizes as starting point a series of structures derived from high-resolution crystal structure of the wild type protein. While many of the structures investigated do not reveal a complete path between the zinc bound water and His-64, several others do indicate the presence of a transient connection even when His-64 is present in its outward conformation. Mutation at the residue 107 also reveals the formation of a new path into the active site. Competing contributions from His-64 sidechain rotation from its outward conformation are also evaluated in terms of optimal path analysis. No indication of a lower catalytic efficiency of the mutant is evident from our results under the condition of thermal stability of the mutant.     

Hyperthermia-induced modulation of killing and mutation by UV and N-methyl-N'-nitro-N-nitrosoguanidine in V79 cells

Hyperthermic exposures of V79 cells did not affect the killing by UV light, whereas it enhanced MNNG-induced killing. Such hyperthermic exposure increased the mutation induction (resistance to 6-thioguanine) by both UV and MNNG. The timing of heat exposure, before or after the treatments, had no effect on the result in cases of cytotoxicity and mutagenesis.     

Genetic divergence among rice strains

Summary For screening better types among 10 strains with the help of the D ² statistic, an experiment was conducted in randomized block design with three replications. 10 plants in each plot were randomly selected and observations were recorded on final plant height, heading duration, effective tillers, number of grains per panicle, yield per plant and 100 grain weight.The observations were analyzed and found to be significant at 1% level.In the study of distance relations the contribution of grain number per panicle to D ² values was found to be maximum. Again, this technique also helped in grouping the 10 strains into four clusters, viz. A, B, C and D, of which B possessed six strains out of 10; A possessed two and C and D one each.Group A comprised 2 selections from the same cross. Group D was composed of a selection from a cross involving Dular and Taichung Native-1 as parents. Group B possessed Dular, two selections from a cross involving Dular as one of the parents, Dharial and N.C.-1626. The constituents of A are expected to be transgressive segregates.Group A was maximally distantly related with D followed in order by C and B. The distance between B and C was small.Group D was found to be the best of all strains studied, followed by B, C and A.Dedicated to Prof. J. Straub on the occasion of his 60th birthday.     

Elimination of Colon Cancer Stem-Like Cells by the Combination of Curcumin and FOLFOX

5-Fluorouracil (5-FU) or 5-FU plus oxaliplatin (FOLFOX) remains the backbone of colorectal cancer chemotherapeutics but with limited success. This could partly be due to the enrichment of cancer stem cells (CSCs) that are resistant to conventional chemotherapy. Therefore, validation of a nontoxic agent that can either cause reversal of chemoresistance or promote the killing of CSCs would be highly desirable. The current study examines whether curcumin, the major active ingredient of turmeric, either alone or together with FOLFOX, would be an effective strategy to eliminate colon CSCs. Exposure of colon cancer HCT-116 or HT-29 cells to FOLFOX that inhibited their growth led to the enrichment of CSC phenotype as evidenced by increased proportion of CD133-, CD44-, and/or CD166-positive cells and epidermal growth factor receptor (EGFR) levels. Treatment of FOLFOX-surviving colon cancer cells with either curcumin alone or together with FOLFOX resulted in a marked reduction in CSCs, as evidenced by the decreased expression of CD44 and CD166 as well as EGFR and by their ability to form anchorage-dependent colonies. They also caused disintegration of colonospheres. Increased expression of EGFR in FOLFOX-surviving cells could be attributed to hypomethylation of the EGFR promoter, whereas an opposite phenomenon was observed when the FOLFOX-surviving cells were treated with curcumin and/or FOLFOX. These changes were accompanied by parallel alterations in the levels of DNA methyltransferase 1. In conclusion, our data suggest that curcumin by itself or together with the conventional chemotherapeutic could be an effective treatment strategy for preventing the emergence of chemoresistant colon cancer cells by reducing/eliminating CSCs.     

Accumulation of glycosphingolipids in human atherosclerotic plaque and unaffected aorta tissues

We have measured the levels of glycosphingolipids and the activityof glycosphingolipid glycosyltransferases in human aortic intimaand media from patients who died of atherosclerosis. The effectsof lactosylceramide (LacCer) and glucosylceramide (GlcCer) fromplaque intima on smooth muscle cell proliferation were assessed.When the GIcCer data was expressed as (pg GlcCer/mg cholesteroland/mg total phospholipid, a 28-fold and 7-told increase inplaque intima compared to normal intima was observed. Similarly,the level of LacCer was elevated 5-fold and 4-fold, respectively,compared to unaffected intima. The activity of UDPGicCer: ceramideß1     

Charge trapping by solitions—A possible transport mechanism in macromolecular systems

Macromolecules and their aggregates possess polar modes which, when excited, cause deformations, which provoke in turn elastic restoring forces. Even the simplest of such models (involving polarization and elastic modes along a chain) admit localized excitations (solitons) endowed with a characteristic degree of stability; and these provide a mechanism for charge trapping which may be of importance in the understanding of the elusively high efficiency of charge transfer over macroscopic distances evidently involved in various biomolecular processes.     

The phytochemistry of the annonaceae

Both alkaloidal and non-alkaloidal compounds so farsolated from Annonaceous plants are reviewed. 319 secondary products have been reported from 150 spe