Introduction. Cold plasma is frequently utilized for the purpose of eliminating microbial contaminants. Under optimal conditions, it can function as plasma medicine for treating various diseases, including infections caused by Candida albicans, an opportunistic pathogen that can overgrow in individuals with weakened immune system.Gap Statement. To date, there has been less molecular study on cold plasma-treated C. albicans.Research Aim. The study aims to fill the gap in understanding the molecular response of C. albicans to cold plasma treatment.Methodology. This project involved testing a cold plasma generator to determine its antimicrobial effectiveness on C. albicans' planktonic cells. Additionally, the cells' transcriptomics responses were investigated using RNA sequencing at various treatment durations (1, 3 and 5 min).Results. The results show that our cold plasma effectively eliminates C. albicans. Cold plasma treatment resulted in substantial downregulation of important pathways, such as 'nucleotide metabolism', 'DNA replication and repair', 'cell growth', 'carbohydrate metabolism' and 'amino acid metabolism'. This was an indication of cell cycle arrest of C. albicans to preserve energy consumption under unfavourable conditions. Nevertheless, C. albicans adapted its GSH antioxidant system to cope with the oxidative stress induced by reactive oxygen species, reactive nitrogen species and other free radicals. The treatment likely led to a decrease in cell pathogenicity as many virulence factors were downregulated.Conclusion. The study demonstrated the major affected pathways in cold plasma-treated C. albicans, providing valuable insights into the molecular response of C. albicans to cold plasma treatment. The findings contribute to the understanding of the antimicrobial efficiency of cold plasma and its potential applications in the field of microbiology.
Enterococcus faecium is an opportunistic pathogen with a remarkable ability to acquire resistance toward multiple antibiotics, including those of last-resort drugs such as vancomycin and daptomycin. The occurrence of vancomycin-resistant E. faecium is on the rise and there is a need to understand the virulence of this organism. One of the factors that contributes to the virulence is the ability to form biofilms. Since bacteria in biofilm state are more resistant to antibiotics and host immune response, understanding the molecular mechanism of biofilm development is important to control biofilm-related diseases. The aim of this study was to determine the global gene expression profiles of an E. faecium strain, VREr5, during the early event of sessile growth compared with its planktonic phase through RNA-sequencing approach. The results clearly illustrated distinct expression profiles of the planktonic and biofilm cells. A total of 177 genes were overexpressed in the biofilm cells. Most of them encode for proteins involved in adherence, such as the ebpABCfm locus. Genes associated with plasmid replication, gene exchange, and protein synthesis were also upregulated during the early event of biofilm development. Furthermore, the transcriptome analysis also identified genes such as fsrB, luxS, and spx that might suppress biofilm formation in VREr5. The putative biofilm-related bee locus was found to be downregulated. These new findings could provide caveats for future studies on the regulation and maintenance of biofilm and development of biomarkers for biofilm-related diseases.
Knowledge about the biogeography of marine bacterioplankton on the global scale in general and in Southeast Asia in particular has been scarce. This study investigated the biogeography of bacterioplankton community in Singapore seawaters. Twelve stations around Singapore island were sampled on different schedules over 1 year. Using PCR-DNA fingerprinting, DNA cloning and sequencing, and microarray hybridization of the 16S rRNA genes, we observed clear spatial variations of bacterioplankton diversity within the small area of the Singapore seas. Water samples collected from the Singapore Strait (south) throughout the year were dominated by DNA sequences affiliated with Cyanobacteria and Alphaproteobacteria that were believed to be associated with the influx of water from the open seas in Southeast Asia. On the contrary, water in the relatively polluted Johor Strait (north) were dominated by Betaproteobacteria, Gammaproteobacteria, and Bacteroidetes and that were presumably associated with river discharge and the relatively eutrophic conditions of the waterway. Bacterioplankton diversity was temporally stable, except for the episodic surge of Pseudoalteromonas, associated with algal blooms. Overall, these results provide valuable insights into the diversity of bacterioplankton communities in Singapore seas and the possible influences of hydrological conditions and anthropogenic activities on the dynamics of the communities.