Screening of potential secondary metabolites
Bacteria, particularly actinomycetes, are great producers of bioactive compounds. In CCB, we have a culture collection known as Microbial Biodiversity Library (MBL). Research conducted in this group includes various assays to screen the presence of potential secondary metabolites from those microbes, such as anti-infective, anti-oxidant, anti-microbial, plant growth promoters, siderophore production, etc.
Currently, a new potential anti-infective agent was successfully isolated and characterized from marine actinomycetes. Streptomyces sp. CCB-PSK 207 was found to rescue Caenorhabditis elegans from Pseudomonas aeruginosa infection through restitution of suppressed lysozyme 7 activities. A hexane partition of the extract from this isolate could promote the survival of PA14-infected worms to more than 60%. In addition, the partition was able to induce the expression of lysozyme 7, an important innate immunity defense molecule of C. elegans.
Besides the anti-infective agent, we have identified and characterized anti-oxidant bioactive metabolites from mangrove Streptomyces. These Streptomyces also showed good anti-microbial activities against several human pathogens. Various assays were performed, including phosphomolybdate assay, DPPH (1, 1, diphenyl-2-picryl hydrazyl) scavenging activity assay, reducing power assay, Beta-carotene bleaching disc diffusion assay, etc. Further elucidation of the bioactive compound structures is currently in progress.
Antimicrobial & plant growth promoters
Recently, agriculture has been faced with destructive activities caused by numerous pests, including microbial pathogens, weeds and insects, which resulted in drastic decrease of crop yield. Screening of new biopesticide agents, plant growth promoters, as well as siderophore producers, will be definitely improving our future agriculture. Based on primary studies, few potential Streptomyces have been characterized. These isolates show the ability of plant growth promoters as well as anti-phytopathogenic producers. Partitioning of the extract and characterization of the bioactive molecules will be conducted to elucidate the structure of the active compound.
Presently, we are also actively screening the secondary metabolites from MBL for other research purposes.