QUALITATIVE ANALYSIS OF ANTIMICROBIAL COMPOUND BY HIGH PERFORMANCE THIN LAYER CHROMATOGRAPHY METHOD

Objective: To perform qualitative analysis of antimicrobial compound by High performance thin layer chromatography method.Methods: Streptomyces sp. 2011 (JF751041) had been isolated from the marine coastal soil of Marina beach, Chennai. Streptomyces sp. 2011 was found to be the most potent isolate and the solvent ethyl acetate was used for extracting the bioactive compounds. The bioactive compounds were separated by solvent extraction and phase separation method. The ethyl acetate solvent containing the extract was subjected to High Performance Thin Layer Chromatography to find out the presence of ester, quinone, macrolide and terpenoids.Results: Ten bacterial and two fungal pathogens were challenged against the crude extract. Salmonella paratyphi, Pseudomonas aeruginosa, Bacillus subtilis were resistant to the extract where as Escherichia coli and Lactobacillus acidophilus were less sensitive. All the other five bacteria and two fungi were showing excellent inhibition diameter. Clotrimazole, Ampicillin and Tetracycline were used as positive controls where as ethyl acetate solvent were used as negative control. The results of High Performance Thin Layer Chromatography proved the presence of ester, macrolide and terpenoids.Conclusion: The results of the antimicrobial activity of Streptomyces sp. 2011 and the presence of bioactive compounds like ester, terpenoid and macrolide clearly proved that the marine soil of Marina beach is a good harbor for isolating novel varieties of antagonistic Streptomyces sp. and for producing broad spectrum antibiotics.Key words: Streptomyces sp. 2011 (JF751041), HPTLC, Antibiotics, Macrolide, Terpenoid, Quinone, Ester, Antimicrobia

Competition between Metals for Binding to Methanobactin Enables Expression of Soluble Methane Monooxygenase in the Presence of Copper

It is well known that copper is a key factor regulating expression of the two forms of methane monooxygenase found in proteobacterial methanotrophs. Of these forms, the cytoplasmic, or soluble, methane monooxygenase (sMMO) is expressed only at low copper concentrations. The membrane-bound, or particulate, methane monooxygenase (pMMO) is constitutively expressed with respect to copper, and such expression increases with increasing copper. Recent findings have shown that copper uptake is mediated by a modified polypeptide, or chalkophore, termed methanobactin. Although methanobactin has high specificity for copper, it can bind other metals, e.g., gold. Here we show that in Methylosinus trichosporium OB3b, sMMO is expressed and active in the presence of copper if gold is also simultaneously present. Such expression appears to be due to gold binding to methanobactin produced by M. trichosporium OB3b, thereby limiting copper uptake. Such expression and activity, however, was significantly reduced if methanobactin preloaded with copper was also added. Further, quantitative reverse transcriptase PCR (RT-qPCR) of transcripts of genes encoding polypeptides of both forms of MMO and SDS-PAGE results indicate that both sMMO and pMMO can be expressed when copper and gold are present, as gold effectively competes with copper for binding to methanobactin. Such findings suggest that under certain geochemical conditions, both forms of MMO may be expressed and active in situ. Finally, these findings also suggest strategies whereby field sites can be manipulated to enhance sMMO expression, i.e., through the addition of a metal that can compete with copper for binding to methanobactin

Methanobactin from Methylocystis sp. Strain SB2 Affects Gene Expression and Methane Monooxygenase Activity in Methylosinus trichosporium OB3b

Methanotrophs can express a cytoplasmic (soluble) methane monooxygenase (sMMO) or membrane-bound (particulate) methane monooxygenase (pMMO). Expression of these MMOs is strongly regulated by the availability of copper. Many methanotrophs have been found to synthesize a novel compound, methanobactin (Mb), that is responsible for the uptake of copper, and methanobactin produced by Methylosinus trichosporium OB3b plays a key role in controlling expression of MMO genes in this strain. As all known forms of methanobactin are structurally similar, it was hypothesized that methanobactin from one methanotroph may alter gene expression in another. When Methylosinus trichosporium OB3b was grown in the presence of 1 μM CuCl2, expression of mmoX, encoding a subunit of the hydroxylase component of sMMO, was very low. mmoX expression increased, however, when methanobactin from Methylocystis sp. strain SB2 (SB2-Mb) was added, as did whole-cell sMMO activity, but there was no significant change in the amount of copper associated with M. trichosporium OB3b. If M. trichosporium OB3b was grown in the absence of CuCl2, the mmoX expression level was high but decreased by several orders of magnitude if copper prebound to SB2-Mb (Cu-SB2-Mb) was added, and biomass-associated copper was increased. Exposure of Methylosinus trichosporium OB3b to SB2-Mb had no effect on expression of mbnA, encoding the polypeptide precursor of methanobactin in either the presence or absence of CuCl2. mbnA expression, however, was reduced when Cu-SB2-Mb was added in both the absence and presence of CuCl2. These data suggest that methanobactin acts as a general signaling molecule in methanotrophs and that methanobactin “piracy” may be commonplace

A prospective, randomized study to evaluate the efficacy of various diuretic strategies in acute decompensated heart failure

AbstractAimTo evaluate the safety and efficacy of various initial strategies of loop diuretic administration in patients with acute decompensated heart failure (ADHF) on diuresis, renal function, electrolyte balance and clinical outcomes.MethodsConsecutive patients admitted with ADHF were randomized into three groups - intravenous furosemide infusion + intravenous dopamine, intravenous furosemide bolus in two divided doses and intravenous furosemide continuous infusion alone. At 48 h, the treating physician could adjust the diuretic strategy. Primary endpoint was negative fluid balance at 24 h after admission. Secondary end points were duration of hospital stay, negative fluid balance at 48, 72, 96 h, the trend of serum electrolytes, and renal function and 30 day clinical outcome (death and emergency department visits).ResultsOverall ninety patients (thirty in each group) were included in the study. There was a greater diuresis in first 24 h (p = 0.002) and a shorter hospital stay (p = 0.023) with the bolus group. There was no significant difference in renal function and serum sodium and serum potassium levels. There was no difference in the number of emergency department visits among the three groups.ConclusionAll three modes of diuretic therapies can be practiced with no difference in worsening of renal function and electrolyte levels. Bolus dose administration with its rapid volume loss and shorter hospital stay might be a more effective diuretic strategy