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Has files: YesSubject: search.filters.subject.Staphylococcus aureus

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    PublicationOpen Access
    A Study on Anti bacterial Properti es of Costus speciosus
    (Faculty of Humanities and Sciences, SLIIT, 2024-12-04) Wijesekara, A; Lanka Kumari, S.R. M. M.; Kasturiarachchi, J
    Anti bioti c resistant bacteria have posed a serious threat to world health in recent years, forcing the investi gati on of alternate sources for anti bacterials. Higher plants are a key source of medicinal compounds. The objecti ve of this study was to evaluate the anti bacterial properti es of C. speciosus against gram-negati ve E. coli and gram-positi ve Staphylococcus aureus, to explore its potenti al as a natural alternati ve to conventi onal anti bioti cs. Leaves, stems, and rhizomes of C. speciosus were extracted using hexane, methanol, and water as solvents with refl ux, sonicati on and macerati o. Anti bacterial acti vity was assessed using the disk diff usion assay, with gentamycin as a positi ve control. The stemmethanolic extract showed greater inhibiti on against both organisms compared to hexane extracts. Stemwater extracts were eff ecti ve only against S. aureus. The rhizome-methanolic extract inhibited E. coli more than S. aureus, while the hexane extract was more eff ecti ve against S. aureus. The rhizome-water extract inhibited the growth of both bacterial strains. Leaf extracts demonstrated signifi cant inhibiti on against E. coli but no acti vity against S. aureus. This study shows that C. speciosus has signifi cant anti bacterial properti es, varying with plant part, solvent, and organism. Given the rise in anti bioti cresistant bacteria, C. speciosus is a promising natural source of anti bacterial agents.
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    PublicationOpen Access
    Supramolecular structure in the membrane of Staphylococcus aureus
    (National Academy of Sciences, 2015-12-22) García-Lara, G. L; Weihs, F; Ma, X; Walker, L; Chaudhuri, R. R; Kasturiarachchi, J. C; Crossley, H; Golestanian, R; Foster, S. J
    All life demands the temporal and spatial control of essential biological functions. In bacteria, the recent discovery of coordinating elements provides a framework to begin to explain cell growth and division. Here we present the discovery of a supramolecular structure in the membrane of the coccal bacterium Staphylococcus aureus, which leads to the formation of a largescale pattern across the entire cell body; this has been unveiled by studying the distribution of essential proteins involved in lipid metabolism (PlsY and CdsA). The organization is found to require MreD, which determines morphology in rod-shaped cells. The distribution of protein complexes can be explained as a spontaneous pattern formation arising from the competition between the energy cost of bending that they impose on the membrane, their entropy of mixing, and the geometric constraints in the system. Our results provide evidence for the existence of a self-organized and nonpercolating molecular scaffold involving MreD as an organizer for optimal cell function and growth based on the intrinsic self-assembling properties of biological molecules.
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    PublicationOpen Access
    Multiple essential roles for EzrA in cell division of Staphylococcus aureus
    (Blackwell Publishing Ltd, 2011-04) Steele, V. R; Bottomley, A. L; Garcia‐Lara, G. L; Kasturiarachchi, J. C; Foster, S. J
    In Bacillus subtilis, EzrA is involved in preventing aberrant formation of FtsZ rings and has also been implicated in the localization cycle of Pbp1. We have identified the orthologue of EzrA in Staphylococcus aureus to be essential for growth and cell division in this organism. Phenotypic analyses following titration of EzrA levels in S. aureus have shown that the protein is required for peptidoglycan synthesis as well as for assembly of the divisome at the midcell and cytokinesis. Protein interaction studies revealed that EzrA forms a complex with both the cytoplasmic components of the division machinery and those with periplasmic domains, suggesting that EzrA may be a scaffold molecule permitting the assembly of the division complex and forming an interface between the cytoplasmic cytoskeletal element FtsZ and the peptidoglycan biosynthetic apparatus active in the periplasm.