Quorum sensing (QS) is a mechanism by which gram-negative bacteria regulate their gene expression by making use of cell density. QS is triggered by a small molecule known as an autoinducer. ...Typically, gram-negative bacteria such as Vibrio produce signaling molecules called acyl homoserine lactones (AHLs). However, their levels are very low, making them difficult to detect. We used thin layer chromatography (TLC) to examine AHLs in different Vibrio species, such as Vibrio alginolyticus, Vibrio parahemolyticus, and Vibrio cholerae, against a standard- Chromobacterium violaceum. Further, AHLs were characterised by high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC–MS). C4-HSL (N- butanoyl- L- homoserine lactone), C6-HSL (N- hexanoyl- L- homoserine lactone), 3-oxo-C8-HSL (N-(3-Oxooctanoyl)-DL-homoserine lactone), C8-HSL (N- octanoyl- L- homoserine lactone), C110-HSL (N- decanoyl- L- homoserine lactone), C12-HSL (N- dodecanoyl- L- homoserine lactone) and C14-HSL (N- tetradecanoyl- L- homoserine lactone) were identified from Vibrio. These results may provide a basis for blocking the AHL molecules of Vibrio, thereby reducing their pathogenicity and eliminating the need for antimicrobials.
<正>Objective:To isolate the multiple drug resistance(MDR) Mycobacterium tuberculosis(M. tuberculosis) and to screen for the bioactive compounds extracted from marine microalgae. Methods:Sixty ...seven collected samples that were confirmed by 16S rDNA analysis as positive with M.tuberculosis infection were subjected to sensitivity test against commercially used front line and second line drugs by absolute concentration method using LJ slants.Seven bacterial isolates numbered I-78,I-101,I-127,I-173,I-202,I-262,I-327 showed resistant for more than 3 drugs were considered as MDR M.tuberculosis.Thus the percentage of 10.4 were recorded MDR-TB. Fifteen marine micro algal extracts were screened for antimycobacterial activity and partial characterization of the active principles was done.Results:The percentage contribution of marine micro algal species on the extraction of antimycobacterials indicated Isochrysis galbana(I. galbana) contain rich bioactive compounds and accounted for 60%inhibition of the total isolates. The percentage contribution of solvents on the extraction of antimicrobials from I.galbana showed that the methanol,chloroform,n-Butanol showed maximum of extraction.The purified eluted compounds(R,0.43) from TLC plate were chromatographed by gas chromatography.The eluted sterol compounds showed 13 unsaturated sterols with 3 major sterols.Conclusions:The present study indicates the presence of unsaturated fatty acids may have the effect on MDR M. tuberculosis,indicating a potential natural alternative to antibiotics.
Marking the fiftieth anniversary of the death of Aldous Huxley (18941963), Temporaries and Eternals focuses on the music column that Huxley wrote for The Weekly Westminster Gazette in 192223. ...Readers of Huxleys novels, essays and travel writing will be aware of the wealth of musical detail in these works, and this book suggests that such references can only be fully understood in the context of the opinions voiced in Huxleys music criticism. Not only does Huxleys column offer a fascinati.
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