Lipopolysaccharide Cross-Tolerance Delays Platelet-Activating Factor-Induced Sudden Death in Swiss Albino Mice: Involvement of Cyclooxygenase in Cross-Tolerance

Lipopolysaccharide (LPS) signaling through Toll-like receptor-4 (TLR-4) has been implicated in the pathogenesis of many infectious diseases. Some believe that TLR-mediated pathogenicity is due, in part, to the lipid pro-inflammatory mediator platelet-activating factor (PAF), but this has been questioned. To test the direct contribution of PAF in endotoxemia in murine models, we injected PAF intraperitoneally into Swiss albino mice in the presence and absence of LPS. PAF alone (5 μg/mouse) caused death within 15–20 min, but this could be prevented by pretreating mice with PAF-receptor (PAF-R) antagonists or PAF-acetylhydrolase (PAF-AH). A low dose of LPS (5 mg/kg body wt) did not impair PAF-induced death, whereas higher doses (10 or 20 mg/kg body wt) delayed death, probably via LPS cross-tolerance. Cross-tolerance occurred only when PAF was injected simultaneously with LPS or within 30 min of LPS injection. Tolerance does not appear to be due to an abundant soluble mediator. Histologic examination of lungs and liver and measurement of circulating TNF-α and IL-10 levels suggested that the inflammatory response is not diminished during cross-tolerance. Interestingly, aspirin, a non-specific cyclooxygenase (COX) inhibitor, partially blocked PAF-induced sudden death, whereas NS-398, a specific COX-2 inhibitor, completely protected mice from the lethal effects of PAF. Both COX inhibitors (at 20 mg/kg body wt) independently amplified the cross-tolerance exerted by higher dose of LPS, suggesting that COX-derived eicosanoids may be involved in these events. Thus, PAF does not seem to have a protective role in endotoxemia, but its effects are delayed by LPS in a COX-sensitive way. These findings are likely to shed light on basic aspects of the endotoxin cross-tolerance occurring in many disease conditions and may offer new opportunities for clinical intervention.     

Spermatozoa input concentrations and RNA isolation methods on RNA yield and quality in bull (Bos taurus)

Sperm RNA can be used to understand the past spermatogenic process, future successful fertilization, and embryo development. To study the sperm RNA composition and function, isolation of good quality RNA with sufficient quantity is essential. The objective of this study was to assess the influence of sperm input concentrations and RNA isolation methods on RNA yield and quality in bull sperm. The fresh semen samples from bulls (n = 6) were snap-frozen in liquid nitrogen and stored at −80 °C. The sperm RNA was isolated using membrane-based methods combined with TRIzol (RNeasy + TRIzol and PureLink + TRIzol) and conventional methods (TRIzol, Double TRIzol, and RNAzol RT). Based on fluorometric quantification, combined methods resulted in significantly (P < 0.05) higher total RNA yields (800–900 ng/30–40 × 10⁶) as compared with other methods and yielded 20 to 30 fg of RNA/spermatozoon. The quality of RNA isolated by membrane-based methods was superior to that isolated by conventional methods. The sperm RNA was observed to be intact as well as fragmented (50–2000 bp). The study revealed that the membrane-based methods with a cocktail of lysis solution and an optimal input concentration of 30 to 40 million sperm were optimal for maximum recovery of RNA from bull spermatozoa.     

Studies on gluconate metabolism in Aspergillus niger

Summary A citric acid accumulating strain of Aspergillus niger adapted to grow on gluconic acid lactone as sole carbon source was studied with regards to the enzymatic changes occurring during its adaptive growth and compared with those of the parent strain cultivated on sucrose.Glucose oxidase, glucose dehydrogenase, gluconate dehydrogenase and enzymes of Entner Doudoroff pathway could not be detected in the strain. Gluconokinase was detected in the strain and its inducible nature was established. An adaptive increase of gluconokinase, phosphogluconate dehydrogenase and ribose phosphate isomerase was observed. While the levels of the above enzymes were significantly higher, that of glucose 6-phosphate dehydrogenase were significantly low indicating the repression of the enzyme. Levels of hexokinase and fructose diphosphate aldolase remained more or less the same as that of parent strain. It was inferred from the results that gluconate metabolism occurs via the pentose phosphate pathway following initial phosphorylation.Part of this work was presented at the 8th Annual Microbiological Congress of Association of Microbiologists of India, held in New Delhi 1967.     

Studies on the phytoplankton of the River Ganges,Varanasi, India Part III “Growth of certain phytoplankton in standard synthetic media”

Summary Six plankton forms: Ankistrodesmus falcatus, A. convolutus, Dictyosphaerium ehrenbergianum, Frogilaria crotonensis, Spirulina platensis and Coelastrum sp. were isolated from the river Ganges and grown in unialgal cultures in three mineral solutions — Chu No. 10, Chu No. 10 with the addition of 5% soil extract, and Allen No. 3, in modified forms for growing Chloro-, Bacillario- and Myxo-phycean forms respectively.     

Fatty acid changes in Althaea rosea tissues during growth

Lipids were isolated from roots, stems, leaves, buds, flowers seeds of Althaea rosea plants at different stages of growth. The lipid contents of al     

Studies on the phytoplankton of the River Ganges,Varanasi, India Part IV “Phytoplankton in relation to fish population”

Summary A detailed and systematic study of the algae present in the guts of several fishes from the river and their percentage composition was carried out. Only a few fishes like Hilsa ilisha, Gadusia chapra and Barbus stigma showed herbivorous and omnivorous habits. Definite grazing of the phytoplankton by fishes was clearly envisaged. Their comparative preference for diatoms was evident.     

Expression of the cry1EC gene in castor (Ricinus communis L.) confers field resistance to tobacco caterpillar (Spodoptera litura Fabr) and castor semilooper (Achoea janata L.)

Castor (cv. DCS-9) has been transformed through Agrobacterium-mediated and particle gun bombardment methods using appropriate vectors containing the Bt chimeric gene cry1EC driven by enhanced 35S promoter. About 81 and 12 putative transformants were regenerated following selection on hygromycin and kanamycin, respectively. Southern analysis of DNA extracted from T₀ plants confirmed integration of the introduced gene in castor genome. The integration and inheritance of the introduced genes was demonstrated up to T₄ generation by PCR and Southern analysis. Southern analysis of two events having single and two copies showed the same pattern of integration in the subsequent generations. Insect feeding experiments conducted in the laboratory by releasing neonate larvae of castor semilooper and S. litura on leaf tissues excised from transgenic and control plants showed varying degrees of larval mortality and slow growth in larvae fed on transgenic leaf tissue. Field bioassays against Spodoptera litura and castor semilooper conducted for eight events in T₁–T₄ generations under net confinement were more informative and events conferring resistance to the two major defoliators were identified.