Diversity and Antimicrobial Activities of Actinobacteria Isolated from Tropical Mangrove Sediments in Malaysia

The aim of this study was to isolate and identify Actinobacteria from Malaysia mangrove forest and screen them for production of antimicrobial secondary metabolites. Eighty-seven isolates were isolated from soil samples collected at 4 different sites. This is the first report to describe the isolation of Streptomyces, Mycobacterium, Leifsonia, Microbacterium, Sinomonas, Nocardia, Terrabacter, Streptacidiphilus, Micromonospora, Gordonia, and Nocardioides from mangrove in east coast of Malaysia. Of 87 isolates, at least 5 isolates are considered as putative novel taxa. Nine Streptomyces sp. isolates were producing potent antimicrobial secondary metabolites, indicating that Streptomyces isolates are providing high quality metabolites for drug discovery purposes. The discovery of a novel species, Streptomyces pluripotens sp. nov. MUSC 135T that produced potent secondary metabolites inhibiting the growth of MRSA, had provided promising metabolites for drug discovery research. The biosynthetic potential of 87 isolates was investigated by the detection of polyketide synthetase (PKS) and nonribosomal polyketide synthetase (NRPS) genes, the hallmarks of secondary metabolites production. Results showed that many isolates were positive for PKS-I (19.5%), PKS-II (42.5%), and NRPS (5.7%) genes, indicating that mangrove Actinobacteria have significant biosynthetic potential. Our results highlighted that mangrove environment represented a rich reservoir for isolation of Actinobacteria, which are potential sources for discovery of antimicrobial secondary metabolites

Discovery of novel rare actinobacteria isolated from mangrove environments in the east coast of Peninsular Malaysia

Mangrove forest is a complex ecology and it refers to a group of tropical trees and shrubs that grows in the intertidal zone. It contains various microorganisms including rare actinobacteria that can produce bioactive compounds with interesting bioactivities. The goals of this research were to describe the taxonomic status of novel rare actinobacteria and to screen their bioactivity for antibacterial, neuroprotective and cytotoxic properties. Three rare actinobacteria strains namely MUSC 115T, MUSC 117T and MUSC 78T were successfully isolated from mangrove sediments, collected from Tanjung Lumpur river, Peninsular Malaysia. Characterization using polyphasic approach showed that strains MUSC 115T and MUSC 117T have many differences with other species of the genus Microbacterium and Sinomonas, respectively. Combined phylogenetic, genotypic, chemotaxonomic, and phenotypic analyses proved that strain MUSC 115T represent a novel species, Microbacterium mangrovi sp. nov., while strain MUSC 117T represent a novel species namely Sinomonas humi sp. nov. Meanwhile, strain MUSC 78T was also characterized by polyphasic approach and results showed that it was different from other genera of the family Intrasporangiaceae. Thus, it can be described as a novel genus, Monashia gen. nov., the type species of which is Monashia flava sp. nov. The successfully characterization of the novel strains have led to the screening of bioactivities on antibacterial, neuroprotective and anticancer properties. The crude extract from all novel strains were prepared using solvent extraction method. Antibacterial screening of the crude extracts demonstrated inhibitory effects against 10 bacteria tested including Methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300, ATCC 70069, ATCC 33591, ATCC BAA-44, Acinetobacter calcoaceticus NBRC 13006, Bacillus subtilis ATCC 31098, Pseudomonas aeruginosa NBRC 112582, Salmonella typhi ATCC 19430, Vibrio parahaemolyticus VP103, and Escherichia coli ATCC 25922. On the other hand, the neuroprotective studies revealed that Microbacterium mangrovi MUSC 115T extract exhibited significant neuroprotective activity in oxidative stress and dementia model. Meanwhile, the extract of strain Monashia flava MUSC 78T was able to protect the SHSY5Y neuronal cells in hypoxia model. Furthermore, the extracts of Microbacterium mangrovi MUSC 115T and Monashia flava MUSC 78T exhibited anticancer effect against Ca Ski cell line. Based on the findings of this study, mangrove environment is a potentially rich source for the discovery of novel rare actinobacteria with interesting bioactivities for the new drugs development

Bacterial pigments:The bioactivities and as an alternative for therapeutic applications

Synthetic pigments have been widely used in various applications since the 1980s. However, the hyperallergenicity or carcinogenicity effects of synthetic dyes have led to the increased research on natural pigments. Among the natural resources, bacterial pigments are a good alternative to synthetic pigments because of their significant properties. Bacterial pigments are also one of the emerging fields of research since it offers promising opportunities for different applications. Besides its use as safe coloring agents in the cosmetic and food industry, bacterial pigments also possess biological properties such as antimicrobial, antiviral, antioxidant and anticancer activities. This review article highlights the various types of bacterial pigments, the latest studies on the discovery of bacterial pigments and the therapeutic insights of these bacterial pigments which hopefully provides useful information, guidance and improvement in future study

Assessing the knowledge of, attitudes towards, and practices in, food safety among migrant workers in Klang Valley, Malaysia

Background: Annually, 600 million individuals are affected by food-borne diseases (FBD), alongside 425,000 fatalities. Improving the general public knowledge of, attitudes towards, and practices in, (KAP) food safety is necessary for minimizing FBD transmission. In Malaysia, migrant workers account for 11.1% of the workforce, with a high proportion involved in food and beverage services. Therefore, this study aimed (i) to evaluate the current food safety KAP, and (ii) to identify the strategies to promote food safety awareness, among migrant workers across occupational sectors in Klang Valley. Method: A survey was conducted with 403 migrant workers through phone interviews and online self-administered questionnaires. Piecewise structural equation modelling and multinomial regression were applied to identify predictor variables for food safety KAP and to explore differences across nationalities. Results: The respondents were Nepalese, Filipino and Indonesian. The majority were male, working in the services industry, had completed high school, aged between 30 and 39 years and had worked in Malaysia for less than ten years. Knowledge was significantly correlated with attitudes and practices. Female respondents had lower knowledge and attitude scores while younger respondents had lower knowledge scores. Indonesian and Filipino respondents had lower knowledge and attitudes scores than Nepalese respondents. Understanding food safety information from social media was positively correlated with the respondents’ food safety knowledge and practices. Conclusion: These findings highlighted: (i) the need to target female, younger, Indonesian and Filipino migrant workers, and (ii) the potential of social media to improve public awareness of food safety and hygienic practices

Antiviral Activities of <i>Streptomyces</i> KSF 103 Methanolic Extracts against Dengue Virus Type-2

Dengue has long been a serious health burden to the global community, especially for those living in the tropics. Despite the availability of vaccines, effective treatment for the infection is still needed and currently remains absent. In the present study, the antiviral properties of the Streptomyces sp. KSF 103 methanolic extract (Streptomyces KSF 103 ME), which consists of a number of potential antiviral compounds, were investigated against dengue virus serotype 2 (DENV-2). The effects of this extract against DENV-2 replication were determined using the quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Findings from the study suggested that the Streptomyces KSF 103 ME showed maximum inhibitory properties toward the virus during the virus entry stage at concentrations of more than 12.5 µg/mL. Minimal antiviral activities were observed at other virus replication stages; adsorption (42% reduction at 50 µg/mL), post-adsorption (67.6% reduction at 50 µg/mL), prophylactic treatment (68.4% and 87.7% reductions at 50 µg/mL and 25 µg/mL, respectively), and direct virucidal assay (48% and 56.8% reductions at 50 µg/mL and 25 µg/mL, respectively). The Streptomyces KSF 103 ME inhibited dengue virus replication with a 50% inhibitory concentration (IC50) value of 20.3 µg/mL and an International System of Units (SI) value of 38.9. The Streptomyces KSF 103 ME showed potent antiviral properties against dengue virus (DENV) during the entry stage. Further studies will be needed to deduce the antiviral mechanisms of the Streptomyces KSF 103 ME against DENV

Profiling of potential antibacterial compounds of lactic acid bacteria against Extremely Drug Resistant (XDR) acinetobacter baumannii

A total of 20 of isolates of lactic acid bacteria (LAB) were selected and screened for antagonistic activity against clinical strains of 30 clinical isolates of extremely drug-resistant (XDR) Acinetobacter baumannii using the well diffusion assay method. Results showed that 50% of the highly LAB strains possessed inhibitory activity against (up to 66%) of the XDR A. baumannii strains tested. The supernatant of the twenty LAB strains was subjected to gas chromatography mass spectrometry (GCMS) revealed that the common compound found in the active isolates against XDR A. baumannii was 3-Isobutyl-2,3,6,7,8,8a-hexahydropyrrolo[1,2-a]pyrazine-1,4-dione, a known potential diketopiperazine group. The molecular docking study against potential antibacterial targets with selected ligands was performed to predict the binding mode of interactions, which is responsible for antibacterial activity. The docking analysis of the potent compounds supported the potential antibacterial activity exhibiting high inhibition constant and binding affinity in silico