Partial activation and induction of apoptosis in CD4(+) and CD8(+) T lymphocytes by conformationally authentic noninfectious human immunodeficiency virus type 1

Increased levels of apoptosis are seen in human immunodeficiency virus (HIV) infection, and this has been proposed as an important mechanism contributing to HIV pathogenesis. However, interpretation of in vitro studies aimed at understanding HIV-related apoptosis has been complicated by the use of high concentrations of recombinant proteins or by direct cytopathic effects of replicating virus. We have developed an inactivation procedure that destroys retroviral infectivity while preserving the structural and functional integrity of the HIV surface proteins. These noninfectious virions interact authentically with target cells, providing a powerful tool to dissect mechanisms of HIV pathogenesis that do or do not require viral replication. Noninfectious CXCR4-tropic HIV-1 virions, but not microvesicles, partially activated freshly isolated CD4(+) and CD8(+) peripheral blood mononuclear cell T lymphocytes to express FasL and Fas, but not CD69 or CD25 (interleukin-2 receptor alpha) and eventually die via apoptosis starting 4 to 6 days postexposure. These effects required conformationally intact virions, as heat-denatured virions or equivalent amounts of recombinant gp120 did not induce apoptosis. The maximal apoptotic effect was dependent on major histocompatibility complex (MHC) class II proteins being present on the virion, but was not MHC restricted. The results suggest that the immunopathogenesis of HIV infection may not depend solely on direct cytopathic effects of HIV replication, but that effects due to noninfectious HIV-1 virions may also contribute importantly.     

Synthesis and evaluation of 4′,5′-dihydrospiro[piperidine-4,7′-thieno[2,3-c]pyran] analogues against both active and dormant Mycobacterium tuberculosis

Need for new drugs to fight against tuberculosis (TB) is increasing day by day. In the present work we have taken a spiro compound (GSK 2200150A) reported by GSK as a lead and we modified the structure of the lead to study the antitubercular activity. For structure activity profiling twenty-one molecules have been synthesized, characterized and evaluated for their antimycobacterial potency against both active and dormant TB. Compound 06, 1-((4-methoxyphenyl)sulfonyl)-4′,5′-dihydrospiro[piperidine-4,7′-thieno[2,3-c]pyran] was found to be the most potent compound (MIC: 8.23?µM) in active TB and was less effective than the lead but more potent than standard first line drug ethambutol. It was also found to be more efficacious than Isoniazid and Rifampicin and equipotent as Moxifloxacin against dormant Mycobacterium tuberculosis (MTB). Compound 06 also showed good inhibitory potential against over expressed latent MTB enzyme lysine ε-amino transferase with an IC₅₀ of 1.04?±?0.32?µM. This compound is a good candidate for drug development owing to potential against both active and dormant stages of MTB.     

Expression of bovine (Bos indicus) interleukin‐18 in Escherichia coli and its biological activity

IL‐18 modulates immune functions by inducing IFN‐γ production and promoting Th1 immune responses. In the present study, we amplified and cloned the sequence (582 bp) encoding full‐length bovine IL‐18 from PBMC stimulated with PHA. The nucleotide and the deduced amino acid sequence of Bos indicus IL‐18 showed an identity of 86–98% compared with IL‐18 sequences of other ruminants. The insert was subcloned into a pET 32a vector and expressed in Escherichia coli as a fusion protein and the matured protein was obtained by caspase I treatment. The specificity of these proteins was confirmed by western blotting. The biological activity of the purified protein was analyzed by its ability to induce IFN‐γ production in PBMC measured by ELISA and qPCR.     

Ring-substituted quinolines as potential anti-tuberculosis agents

We report in vitro antimycobacterial properties of ring-substituted quinolines (series 1-4) constituting 56 analogues against drug-sensitive and drug-resistant M. tuberculosis H37Rv strains. The most effective compounds 2h (R1 = R2 = c-C6H11, R3 = NO2, series 1) and 13g (R1 = OC7H15, R2 = NO2, series 4) have exhibited an MIC value of 1 microg/mL against drug-sensitive M. tuberculosis H37Rv strain that is comparable to first line anti-tuberculosis drug, isoniazid. Selected analogues (2d, 2g, 2h, 4e, 6b, 13b, 13g, and 14e, MIC: < or = 6.25 microg/mL) upon further evaluation against single-drug-resistant (SDR) strains of M. tuberculosis H37Rv have produced potent efficacy in the range between 6.25 and 50 microg/mL.     

Comparative Chemical Characterization of Pigmented and Less Pigmented Cell Walls of Alternaria tenuissima

Alternaria tenuissima, the parasitic fungus, was obtained from the pruned upper-cut surfaces of mulberry stems. This fungus contains dark pigment because of the presence of melanin in the cell wall. To obtain less-pigmented cell walls, this fungus was grown under dark condition. When the pigmented and less-pigmented cell walls were chemically analyzed, no differences were observed in amino-acid composition, hexoses, or pentoses. However, in pigmented cell walls, higher contents of melanin (2.6%) were found than in less-pigmented cell walls (0.3%). Interestingly, a significant difference was observed in the relative fatty-acid compositions between these two types of cell walls. Among the major fatty acids, there were increased concentrations of tetradecanoic acid (C14:0), hexadecanoic acid (C16:0), 9-hexadecenoic acid (C16: 1,Δ9), and 9-octadecanoic acid (C18:1,Δ9) and a concomitant decrease in 9,12-octadecadienoic acid (C18:2,Δ9,12) in less-pigmented compared with pigmented cell walls. This difference in fatty-acid composition may be related to the higher percentage of melanin in the pigmented than the less-pigmented cell walls. Lesser amounts of 9,12-octadecadienoic acid in less-pigmented cell walls may have been caused by the growth of the fungus under environmental stress conditions. An interesting observation was the presence in pigmented cell walls only of methyl-substituted fatty acids with carbon numbers C14 to C17, but their occurrence could not be ascertained in the present study.     

Comparison of ribosomes from gram-positive and gram-negative bacteria with respect to the presence of protein S1

Ribosomes from Gram-positive and Gram-negative bacteria have been analysed for the presence of ribosomal protein S1 by three methods, sodium dodecyl sulfate polyacrylamide gel electrophoresis, immunoreaction with E. coli anti-S1 and chromatography on poly (U)-Sepharose. We observed that protein S1 is predominantly present in Gram-negative bacteria in comparison with Gram-positive bacteria. Exceptions are noted in both species.     

Identification of intramolecular interactions in adrenergic receptors.

Adrenergic receptors are representative of a large family of plasma membrane receptors that interact with G proteins during the process of transmembrane signal transduction. G protein-coupled receptors have a primary structure that is homologous to bacteriorhodopsin and are proposed to have a similar three-dimensional structure; however, it has not yet been possible to examine this hypothesis experimentally. We have used a novel mutagenesis approach to identify intramolecular interactions. Our results indicate that specific amino acids in the seventh hydrophobic segment of alpha 2 and beta 2 adrenergic receptors lie adjacent to the first hydrophobic segment. These studies provide the first experimental evidence defining spatial relationships that exist in the three-dimensional structure of adrenergic receptors.