The surge of medical devices associated with nosocomial infection (NI) cases, especially by multidrug-resistant (MDR) bacterial strains, is one of the pressing issues of present health care systems. Metal oxide nanoparticles (MNPs) have become promising antibacterial agents against a wide range of bacterial strains. This work study is on the bactericidal capacity of heterogeneous TiO 2 /ZnO nanocomposites with different weight percentages and concentrations against common MDR and non-MDR bacterial strains. The profiles on disk diffusion, minimum inhibitory concentration, minimum bactericidal concentration, tolerance determination, time-kill, and biofilm inhibition assay were determined after 24 h of direct contact with the nanocomposite samples. Findings from this work revealed that the heterogeneous TiO 2 /ZnO nanocomposite with a 25T75Z weight ratio showed an optimal tolerance ratio against Grampositive and -negative bacteria, indicating their bactericidal capacity. Further observation suggests that higher molar ratio of Zn 2+ may possibly involve generation of active ion species that enhance bactericidal effect against Gram-positive bacterial strains, especially for the MDR strains. Nano-based technology using MNPs may provide a promising solution for the prevention and control of NIs. Further work on biocompatibility and cytotoxicity profiles of this nanocomposite are needed.

Dillapiole is one of the major compounds in Peperomia pellucida. Dillapiole exerts cytotoxicity effect on several cancer cells such as breast and colon with a minimal effect on normal cells. However, its effect on cancers in head and neck region remains ambiguous. Therefore, in the current study, the cytotoxicity effect of dillapiole on human nasal squamous cell carcinoma, RPMI 2650 and the underlying mechanism were investigated. Normal human gingival fibroblast, HGnF cells was used as comparison. Cisplatin and untreated cells were used as positive and negative controls, respectively. Cell cytotoxicity was determined using WST-1 assay; and validated by trypan blue exclusion assays. Cell death mechanism was determined using Annexin V-FITC detection kit and analyzed by flow cytometer. The cytotoxic effect of dillapiole on RPMI 2650 cells was shown significantly increased with the increasing amount of dillapiole from 25.93 ± 6.39 % to 83.87 ± 8.43 % (p<0.05, n=3) with the respective IC50 and IC75 of 46 µM and 125 µM. None of both IC50 and IC75 were obtained for HGnF cells up to 150 µM. Loss of normal shape, cytoplasm shrinkage and reduction in cell volume were detected in RPMI 2650 cells after dillapiole treatment at respective IC50 (46 µM) and IC75 (125 µM), indicating apoptosis. These findings indicate that dillapiole cytotoxicity effect is more selective towards RPMI 2650 compared to HGnF cells and the mechanism of death was through the induction of apoptosis.

One of the top species in the aquaculture sector, known as striped catfish or Pangasianodon hypophthalmus, is an important and valuable freshwater fish in many countries. Due to the high demand for this species, their number has declined to "threatened" levels.  Hence, the purpose of this study is to analyse the genetic variation of wild and cultured striped catfish collected from five producers in Asian countries; Thailand, Vietnam, Indonesia, India, and Philippines, by using mitochondrial DNA partial region data sequence; CO1 and cytochrome b gene. Population analyses using 395 base pairs length for CO1 and 275 base pairs length of cytochrome b partial region nucleotide sequence have shown no significance difference between wild and cultured striped catfish. Vietnam species had shown a wide range of genetic distance of the intrapopulation compared with other countries in the range of 0.000-0.040 for CO1 gene and 0.003-0.008 for cytochrome b gene. The Neighbour-joining method has also been used to construct phylogenetic trees using CO1 gene; the tree formed few subclades with mixed populations, and the tree using cytochrome b showed only Vietnam species divided into a few sub-populations. For the other four countries, Thailand, Indonesia, India, and Philippines were in the same group. Hence, this study's findings may provide a reference for inter and intra-relationships of P. hypophthalmus that may help in the aquaculture activity of this striped catfish.

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