Diversity of microorganisms in solar salterns of Tamil Nadu,India

In this study, the diversity of prokaryotes inhabiting crystallizer ponds of three solar salterns, located along Bengal Bay in Tamil Nadu, India was examined. Unlike other salterns studied the Tamil Nadu salterns are fed by hypersaline spring water mixed with seawater and led to the ponds from bore wells. In addition, prokaryotic community development is restricted as salterns operate only during the arid part of the year. Both culture-based and culture-independent polymerase chain reaction 16S rRNA molecular phylogenetic approaches were employed. Representatives of the family Halobacteriaceae dominated in cultivable portion of diversity encountered with members of genera Haloferax, Halorubrum, Haloarcula, Halobacterium and Halogeometricum recovered in pure culture. In contrast, members of Bacteria were recovered from only one sampling site and were represented by members of genera Salinibacter, Cytophaga and Marinococcus. Based on culture-independent sampling, the predominant members of the haloarchaeal crystallizer community belonged to the genus Natrinema.     

Effect of 1,25 dihydroxyvitamin D3 on intracellular IFN-γ and TNF-α positive T cell subsets in pulmonary tuberculosis

We studied the immunomodulatory effect of 1,25(OH)₂D₃ on single cell expression of IFN-γ and TNF-α cytokines in T cell subsets of pulmonary tuberculosis (PTB) patients (n = 22) and normal healthy subjects (n = 22). Peripheral blood mononuclear cells (PBMCs) were cultured with live Mycobacterium tuberculosis (MTB) with or without 1,25(OH)₂D₃ (10^?7 M) for 48 h. T cell subsets positive for IFN-γ and TNF-α were enumerated by flow cytometry and the culture supernatants were assayed for both the cytokines using ELISA. In both NHS and PTB patients, a significantly reduced percentage of IFN-γ and TNF-α expressing CD3+, CD3+CD4+ and CD3+CD8+ T cells were observed in cultures stimulated with live MTB and treated with 1,25(OH)₂D₃ compared to cultures without 1,25(OH)₂D₃ (NHS; CD3+ IFN-γ+: p < 0.0001; CD3+TNF-α +: p = 0.0292 and PTB; CD3+ IFN-γ+: p = 0.0292; CD3+ TNF-α +: p = 0.0028). The levels of IFN-γ and TNF-α in the culture supernatants of 1,25(OH)₂D₃ treated cultures were also found to be significantly decreased in both groups (NHS; IFN-γ: p = 0.0001; TNF-α: p < 0.0001) and (PTB; IFN-γ: p < 0.0001; TNF-α: p < 0.0001). A positive correlation was observed between IFN-γ and TNF-α expressing CD3+CD8+ T cells in MTB stimulated cultures treated with or without 1,25(OH)₂D₃ in NHS (p = 0.0001; p = 0.001, respectively) and PTB patients (p = 0.002; p = 0.005, respectively). The present study revealed the suppressive effect of 1,25(OH)₂D₃ on single cell expression of IFN-γ and TNF-α by CD3+CD4+ and CD3+CD8+ T cells in pulmonary tuberculosis. This suppressive effect of 1,25(OH)₂D₃ on proinflammatory and Th1 cytokine positive cells might have a role in reducing inflammation at the site of infection.     

Curcumin prevents free radical-mediated cataractogenesis through modulations in lens calcium

The generation of free radicals has been implicated in the causation of cataract, and compounds that can scavenge free radicals ameliorate the disease process. This study investigated the possible free radical scavenging potential of curcumin at a dose of 75 mg/kg body wt on selenium-induced cataract in rat pups. Intraperitoneal injection of sodium selenite (15 μmol/kg body wt) into 8- to 10-day-old rat pups led to severe oxidative stress in the eye lens as evidenced by increased nitric oxide, superoxide anion, and hydroxyl radical generation and inducible nitric oxide synthase expression that probably led to cataract formation. Selenium exposure also caused an increase in total calcium in the eye lens and significantly inhibited the activity of Ca²⁺ ATPase but not Na⁺/K⁺ ATPase or Mg²⁺ ATPase. On the other hand, pretreatment with curcumin, but not simultaneous or posttreatment, led to a decrease in oxidative stress and also rescued the selenium-mediated increase in lens Ca²⁺ and inhibition of Ca²⁺ ATPase activity in the eye lens. The results of this study demonstrate that an increase in free radical generation triggered by selenium could cause inactivation of lens Ca²⁺ ATPase leading to Ca²⁺ accumulation. This enhanced Ca²⁺ can cause activation of calpain-mediated proteolysis in the lens, resulting in lens opacification. Curcumin in this study was able to prevent selenium-induced oxidative stress leading to activation of Ca²⁺ ATPase and inhibition of lens opacification. Thus, curcumin has the potential to function as an anticataractogenic agent, possibly by preventing free radical-mediated accumulation of Ca²⁺ in the eye lens.     

Effects of angiotensin-II receptor blocker candesartan cilexetil in rats with dilated cardiomyopathy

We examined effects of an angiotensin-II receptor blockers, candesartan cilexetil, in rats with dilated cardiomyopathy after autoimmune myocarditis. Candesartan cilexetil showed angiotensin-II blocking action in a dose-dependent manner in rats with dilated cardiomyopathy. Twenty-eight days after immunization, surviving Lewis rats were divided into four groups and given candesartan cilexetil at 0.05 mg/kg, 0.5 mg/kg or 5 mg/kg per day (Group-C0.05, n = 15, Group-C0.5, n = 15 and Group-C5, n = 15, respectively) or vehicle alone (Group-V, n = 15). After oral administration for 1 month, the left ventricular end-diastolic pressure and heart weight/body weight ratio were lower in Group-C0.05 (13.3± 1.1 mmHg and 3.7± 0.2 g/kg, respectively), in Group-C0.5 (8.0± 0.9 mmHg and 3.3± 0.1 g/kg, respectively) and in Group-C5 (5.5± 1 mmHg and 3.1± 0.1 g/kg, respectively) than in Group-V (13.5± 1.0 mmHg and 3.8± 0.2 g/kg, respectively). The area of myocardial fibrosis was also lower in Group-C0.05 (25± 3%), in Group-C0.5 (20± 3%), and in Group-C5 (12± 1%) than in Group-V (32± 4%). Furthermore, expressions of transforming growth factor-1 and collagen-III mRNA were suppressed in Group-C0.05 (349± 23% and 395± 22%, respectively), Group-C0.5 (292± 81% and 364± 42%, respectively) and in Group-C5 (204± 63% and 259± 33%, respectively) compared with those in Group-V (367± 26% and 437± 18%, respectively). These results suggest that candesartan cilexetil can improve the function of inefficient heart. (Mol Cell Biochem 269: 137–142, 2005)     

Cloning of the genes of the chitin utilization regulon of Serratia liquefaciens.

The set of genes that determine the expression of the enzymes involved in chitin degradation by Serratia liquefaciens was cloned. The role of each gene was investigated, and for the first time regulatory genes were identified in this system. The chiA and chiB genes coded for separate chitinase activities. The chiC region coded for a chitobiase activity, but it was not formally separated from chiB. Transposon mutagenesis and deletion analysis identified a region, chiD, whose absence led to higher expression of chiA, chiB, and chiC. chiD may therefore be a gene that codes for a repressor. Loss of function of another adjacent region, chiE, prevented induction unless a chiE+ strain was a near neighbor, suggesting that this gene may code for a protein that is involved in the synthesis of the inducer. chiB, chiC, chiD, and chiE are closely linked, while chiA is in a separate location on the chromosome.     

Phyto-chemical and biological activity of Myristica fragrans,an ayurvedic medicinal plant in Southern India and its ingredient analysis

The major aspects of using plant-derived medications are significantly safer and secure than synthetic ones. The n-hexane seed extract of ayurvedic medicinal plants Myristica fragrans was also utilized as food ingredients have analyzed for phytochemical existence by Gas Chromatography-mass spectrometry (GC–MS). Twenty-three phytoconstituents were identified with elemicin (24.44%) as the major constituent. Lipid peroxidase, catalase and DPPH assays were performed using the isolated elemicin and the results revealed significant antioxidant activity. The antibacterial study revealed that elemicin showed MIC of 31.25 μg/mL against Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhi, and 62.5 μg/mL against Klebsiella pneumonia and Staphylococcus aureus. Elemicin exhibited better antifungal activity against Candida tropicalis and Aspergillus flavus than Aspergillus niger, Penicillium chrysogenum and Trichophyton rubrum. The study implies that the elemicin isolated from Myristica fragrans possess promising bioactive properties and can be crucially utilized in the development of therapeutic agents and food preservatives.     

RNAi and RNAa--the yin and yang of RNAome

RNA interference (RNAi) is a powerful technology with huge applications for functional genomics, target identification in drug discovery and elucidation of molecular signaling pathways. Current RNAi studies have demonstrated the clinical potential of small interfering RNAs (siRNAs) in metabolic diseases, cancer, AIDS, malaria, neurodegenerative disorders, dental diseases and other illnesses. Interestingly, recent studies have shown that the small RNA molecules, either indigenously produced as microRNAs (miRNAs) or exogenously administered synthetic dsRNAs could effectively activate a particular gene in a sequence specific manner instead of silencing it. This novel, but still uncharacterized, phenomenon has been termed as RNA activation (RNAa). The paradoxical concept of Yin and Yang, which describe two primal opposing but complementary principles, can potentially be applied to elucidate the complex phenomenon of RNAa/RNAi in the RNAome. This warrants a proper understanding of the RNAi/RNAa molecular pathways in living organisms before any of the small dsRNAs can potentially be exploited for therapeutics in human beings.