Angiotensin converting enzyme inhibitory activity of amino acid esters of carbohydrates

L-alanyl-D-glucose, L-valyl-D-glucose, L-phenylalanyl-D-glucose and L-phenylalanyl-lactose esters were synthesized enzymatically using two lipases viz., Rhizomucor miehei lipase (RML) and porcine pancreas lipase (PPL) and tested for their potential as inhibitors of angiotensin converting enzyme (ACE) in vitro. The esters exhibited concentration related ACE inhibitory activity. The potency of the various esters measured in terms of IC50 values were as follows: L-phenylalanyl-D-glucose, IC50-0.121 mM (mixture of five diastereomeric esters: 6-O-24.1%; 3-O-23.3%; 2-O-19.2%; 2,6-di-O-16.6% and 3,6-di-O-16.8% from the total yield of 92.4%); L-phenylalanyl-lactose, IC50-0.229 mM (mixture of three diastereomeric esters: 6-O-42.1%; 6'-O-30.9%; and 6,6'-di-O-27.0% from the total yield of 50.58%); alanyl-D-glucose, IC50-0.23 mM (mixture of five diastereomeric esters: 6-O-46.7%; 3-O-11.5%; 2-O-19.9%; 2,6-di-O-6.6% and 3,6-di-O-15.3% from the total yield of 26.5%) and L-valyl-D-glucose, IC50-0.396 mM (mixture of five diastereomeric esters: 6-O-32.4%; 3-O-26.5%; 2-O-26.4%; 2,6-di-O-8.8% and 3,6-di-O-5.9% from the total yield of 68.2%). These in vitro data suggest a potential therapeutic role for the aminoesters of carbohydrates as inhibibitors of ACE.     

Wound healing property of ethanolic extract of leaves of Hyptis suaveolens with supportive role of antioxidant enzymes

Ethanolic extract of leaves of Hyptis suaveolens was evaluated for its wound healing activity in ether-anaesthetized Wistar rats at two different doses (400 and 800 mg/kg) using incision, excision, and dead space wound model. Significant increase in skin breaking strength, granuloma breaking strength, wound contraction, hydroxyproline content and dry granuloma weight and decrease in epithelization period was observed. A supportive study made on granuloma tissue to estimate the levels of catalase and superoxide dismutase recorded a significant increase in the level of these antioxidant enzymes. Granuloma tissue was subjected to histopathological examination to determine the pattern of lay-down for collagen using Van Gieson and Masson Trichrome stains. Enhanced wound healing activity may be due to free radical scavenging action of the plant and enhanced level of antioxidant enzymes in granuloma tissue. Better collagenation may be because of improved antioxidant studies.     

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.     

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.     

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.     

Magic angle spinning NMR-based metabolic profiling of head and neck squamous cell carcinoma tissues

High-resolution magic-angle spinning (HR-MAS) proton NMR spectroscopy is used to explore the metabolic signatures of head and neck squamous cell carcinoma (HNSCC) which included matched normal adjacent tissue (NAT) and tumor originating from tongue, lip, larynx and oral cavity, and associated lymph-node metastatic (LN-Met) tissues. A total of 43 tissues (18 NAT, 18 Tumor and 7 LN-Met) from 22 HNSCC patients were analyzed. Principal Component Analysis of NMR data showed a clear classification between NAT and tumor tissues, however, LN-Met tissues were classified among tumor. A partial least-squares discriminant analysis model generated from NMR metabolic profiles was used to differentiate normal from tumor samples (Q(2) > 0.80, Receiver Operator Characteristic area under the curve >0.86, using 7-fold cross validation). HNSCC and LN-Met tissues showed elevated levels of lactate, amino acids including leucine, isoleucine, valine, alanine, glutamine, glutamate, aspartate, glycine, phenylalanine and tyrosine, choline containing compounds, creatine, taurine, glutathione, and decreased levels of triglycerides. These elevated metabolites were associated with highly active glycolysis, increased amino acids influx (anaplerosis) into the TCA cycle, altered energy metabolism, membrane choline phospholipid metabolism, and oxidative and osmotic defense mechanisms. Moreover, decreased levels of triglycerides may indicate lipolysis followed by β-oxidation of fatty acids that may exist to deliver bioenergy for rapid tumor cell proliferation and growth.     

Efficacy of extraction methods for lipid and fatty acid composition from fungal cultures

The efficacy of three extraction methods for determining the lipid and fatty acid composition of six fungal cultures was studied. The extraction methods were: chloroform/methanol (2:1), hexane/isopropanol (3:2) and Soxhlet extraction by using hexane. The total lipid and fatty acid composition varied in fungal cultures depending on the extraction conditions. Of the three methods, chloroform/methanol (2:1) was found to be the best for extraction of lipid and fatty acids from fungal cultures.     

Inverse relationship between carotenoid and lipid formation in Rhodotorula gracilis according to the C/N ratio of the growth medium

Production of carotenoid by Rhodotorula gracilis was highest at 26 mg/g dry weight with a carbon/nitrogen (C/N) ratio in the medium of 10:1. This was 15 times higher than when the C/N ratio was 160:1. With this high C/N ratio, the yeast produced up to 55% lipid compared only 20% lipid with the low C/N ratio. Both carotenoid and lipid production were non-growth associated.