Browsing by Author "Seneviratne, K .L"

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    In Vitro Antibacterial Activity of Sulphur Nanoparticles as a Possible Application to Control Bacterial Blight Caused by Xanthomonas spp. in Anthurium
    (Faculty of Humanities and Sciences, SLIIT, 2022-09-15) Peiris, S.E; Malwattage, G; Ratnayake, R. D; Seneviratne, K .L; Peiris, C.N
    Anthurium blight is caused by Xanthomonas spp. which is regarded as the most threatening disease to the anthurium industry worldwide. Therefore, the current study was carried out to determine whether the application of sulphur nanoparticles (SNPs) is a possible solution for treating anthurium cultivars infected with Xanthomonas spp. The bacterium Xanthomonas was isolated using standard methods and a single bacterial colony was isolated using nutrient agar. The colonies were identified as Xanthomonas spp as they were gram-negative, motile rods due to the colony characters like yellow color because of the xanthin produced. The symptoms appeared in the pathogenicity test which was carried out by injecting purified Xanthomonas sp. into disease free anthurium plants confirmed the identification of the bacterial strain. Time-kill assay was conducted using Staphylococcus aureus, Escherichia coli and isolated Xanthomonas spp to investigate the behavior of SNPs. The results showed that suspension treated with 1g of SNPs for 30 minutes inhibited growth of Staphylococcus aureus colonies showing mean number of 7.92 CFU/ml compared to the control (mean number of colonies 9.09 CFU/ml ) treatment following 12 hours incubation. However, Escherichia coli, and isolated gram-negative rods (Xanthomonas spp) did not show positive influence for SNPs when compared to the control treatment. Therefore, further investigation is required to reach firm conclusions about this matter because the antimicrobial activity of SNPs varies depending on the type of target microorganisms, method and solvent used to dissolve SNPs.
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    Visible Light Active Silver Decorated Iron Titanate/Titanium Dioxide Nanohybrid for Sterilization of Explants Grown by In Vitro Technique
    (John Wiley and Sons, 2022-12-04) Seneviratne, K .L; Munaweera, I; Peiris, S. E; Kodithuwakku, P; Peiris, C. N; Kottegoda, N
    Visible light (VL) active silver decorated iron titanate/titanium dioxide (Ag-FeTiO3/TiO2) nanohybrids derived from natural ilmenite sand effectively cleanse the exophytic plant pathogens in explants grown by in vitro techniques. VL active nanohybrid is synthesized by acid-hydrolysis of natural ilmenite, followed by precipitation of the lixivium and decoration with Ag onto FeTiO3/TiO2 nanoparticles, and finally calcination under a nitrogen environment to obtain Ag-FeTiO3/TiO2. A morphological study conducted using transmission electron microscopy (TEM) confirms the formation of Ag-FeTiO3/TiO2. Powder X-ray diffraction (PXRD) analysis shows that the nanohybrid primarily consists of anatase, iron titanate (FeTiO3), Ag2O, and Ag. X-ray photoelectron spectroscopy (XPS) study suggests the presence of Ag0/Ag2O/Fe2O3 composites on the FeTiO3/TiO2 particle surface. The optical band gap significantly changes from 3.14 eV (ilmenite) to 2.80 eV after the decoration of FeTiO3/TiO2 with Ag. This nanohybrid is utilized as a surface-sterilizing agent for in vitro establishment of the Dracaena sanderiana Sander ex Mast plant. Findings illustrate Ag-FeTiO3/TiO2 nanohybrid-based photo-sterilization leads to the survival of 90% of the microbes’ free cultures while the material can be re-used due to its photocatalytic behavior. Thus, the newly synthesized nanohybrid can replace harmful sterilization agents used in tissue culture techniques