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Karaikkudi, India

Alagappa University is on about 420 acres in the business town of Karaikudi in Sivaganga District in Tamil Nadu, India. Karaikudi is 400 km south of Madras on the Madras–Rameswaram line and is accessible from Tiruchirappalli and Madurai in about 2 hours by road and rail. This seat of higher education has emerged from the galaxy of institutions founded by R.M. Alagappa Chettiar. Alagappa University was brought into existence by a special Act of the state government in May 1985 with the objective of fostering research, development, and dissemination of knowledge. Alagappa University is recognized by the UGC, Government of India. It was converted from a unitary type to an affiliating type by the Tamil Nadu Universities Act, 2002, with a view to widen the horizon of its academic activities by bringing into its jurisdiction the Arts and Science colleges in the districts of Ramanathapuram and Sivaganga. Further, as per this Act, the government colleges in the above districts have become the constituent colleges of Alagappa University. As a member of the AIU and the Association of Commonwealth Universities , it has rewarding relations with other academic institutions, research laboratories and industrial establishments that promise a spectacular feature. The university's motto is “Excellence in Action.” Wikipedia.

Staphylococcus aureus is now amongst the most important pathogenic bacteria responsible for bloodstream nosocomial infections and for biofilm formation on indwelling medical devices. Its increasing resistance to common antibiotics, partly attributed to its ability to form biofilms, is a challenge for the development of new antimicrobial agents. Accordingly, the goal of this study was to evaluate the effect of a coral associated actinomycete (CAA)-3 on S. aureus biofilms both in vitro and in vivo. Methanolic extracts of CAA-3 showed a reduction in in vitro biofilm formation by S. aureus ATCC 11632, methicillin resistant S. aureus ATCC 33591 and clinical isolates of S. aureus at the biofilm inhibitory concentration (BIC) of 0.1 mg ml(-1). Furthermore, confocal laser scanning microscope (CLSM) studies provide evidence of CAA-3 inhibiting intestinal colonisation of S. aureus in the nematode Caenorhabditis elegans. To conclude, this study for the first time, reports CAA as a promising source of anti-biofilm compounds, for developing novel drugs against highly resistant staphylococcal biofilms.

Biofilm formation is a critical problem in nosocomial infections and in the aquaculture industries and biofilms show high resistance to antibiotics. The aim of the present study was to reveal a novel anti-biofilm compound from marine bacteria against antibiotic resistant gram-positive and gram-negative biofilms. The bacterial extract (50 μg ml(-1)) of S6-01 (Bacillus indicus = MTCC 5559) showed 80-90% biofilm inhibition against Escherichia coli, Shigella flexneri, Proteus mirabilis and S6-15 (Bacillus pumilus = MTCC 5560) showed 80-95% biofilm inhibition against all the 10 tested organisms. Furthermore, they also reduced the hydrophobicity index and extracellular polymeric substances (EPS) production. Structural elucidation of the active principle in S6-15 using GC-MS, (1)H NMR, and (13)C NMR spectral data revealed it to be 4-phenylbutanoic acid. This is the first report of 4-phenylbutanoic acid as a natural product. The purified compound (10-15 μg ml(-1)) showed potential activity against a wide range of biofilms. This study for the first time, reports a novel anti-biofilm compound from a marine bacterium with wide application in medicine and the aquaculture industry.

Background & objectives: Subinhibitory concentrations (sub-MICs) of antibiotics, although not able to kill bacteria, but influence bacterial virulence significantly. Fluoroquinolones (FQs) which are used against other bacterial pathogens creates resistance in non-targeted Streptococcus pyogenes. This study was undertaken to characterize the effect of sub-MICs of FQs on S. pyogenes biofilm formation. Methods: Biofilm forming six M serotypes M56, st38, M89, M65, M100 and M74 of S. pyogenes clinical isolates were challenged against four FQs namely, ciprofloxacin, ofloxacin, levofloxacin and norfloxacin. The antibiofilm potential of these FQs was analysed at their subinhibitory concentrations (1/2 to 1/64 MIC) using biofilm assay, XTT reduction assay, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Results: Among the four FQs tested, ofloxacin and levofloxacin at 1/2 MIC showed the maximum inhibition (92%) of biofilm formation against M56 and M74 serotypes. FQs effectively interfered in the microcolony formation of S. pyogenes isolates at 1/2 to 1/8 sub-MICs. Inhibition of biofilm formation was greatly reduced beyond 1/16 MICs and allowed biofilm formation. XTT reduction assay revealed the increase in metabolic activity of S. pyogenes biofilm against the decrease in FQs concentration. SEM and CLSM validated the potential of sub-MICs of FQs against the six S. pyogenes. Interpretation & conclusions: Our results showed that the inhibitory effect all four FQs on S. pyogenes biofilm formation was concentration dependent. FQs at proper dosage can be effective against S. pyogenes and lower concentrations may allow the bacteria to form barriers against the antibiotic in the form of biofilm.

Thiagarajan R.,SASTRA University | Manikandan R.,Alagappa University
Free Radical Research | Year: 2013

The major causes for cataract formation are free radicals, and these free radicals are neutralized by the presence of endogenous antioxidants in the eye. Using xenobiotics, it has been confirmed that free radicals mediate the formation of cataract. Two cataract model-selenite model and the diabetic cataract model-have been developed to study the pathophysiology of cataract formation due to free radicals and the role of antioxidants during the process of cataractogenesis. This review focuses on natural compounds with antioxidant properties that could actually be applied as an interventional strategy on a large scale and are also relatively inexpensive. A brief overview of plants with antioxidant properties that in addition possess potential anti-cataract properties has been discussed. In addition to plants, three natural compounds (curcumin, vitamin C and vitamin E), on which a lot of data exist showing anti-cataract and antioxidant activities, have also been discussed. These antioxidants can be supplemented in the diet for a better defence against free radicals. Studies on vitamin C and vitamin E have proved that they are capable of preventing lipid peroxidation, thereby preventing the generation of free radicals, but their efficacy as anti-cataract agent is questionable. Unlike vitamins C and E, curcumin is well established as an anti-cataract agent, but the issue of curcumin bioavailability is yet to be addressed. Nanotechnology proves to be a promising area in increasing the curcumin bioavailability, but still a lot more research needs to be done before the use of curcumin as an effective anti-cataract agent for humans. © 2013 Informa UK, Ltd.

Selvam S.,Alagappa University | Sundrarajan M.,Alagappa University
Carbohydrate Polymers | Year: 2012

Poly-N-vinyl-2-pyrrolidone functionalization was done for improved the dyeability of dichlorotriazine dyes on cotton fabric. The synthesized ZnO nanoparticles were padded on functionalized cotton fabrics to improve antibacterial activity. The modification effects were characterized by FTIR, XRD, SEM and EDX studies. The antibacterial activity was done against Staphylococcus aureus and Escherichia coli bacterium. The dye exhaustion and fastness properties were analyzed for dyeing with sodium chloride, sodium sulfate and trisodium citrate bio-salt as exhausting agents. The functionalized cotton fabric showed improved dye uptake and good fastness properties. Poly-N-vinyl-2-pyrrolidone with ZnO nanoparticles padded fabrics showed very good antibacterial activity. © 2011 Elsevier Ltd. All rights reserved.

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