2. Screening of actinomycetes for bioactive compound

Objectives: To screen actinomycetes which produce novel compounds from soil and plant

           Actinomycetes¬†are gram-positive bacteria with a high G+C content. They are well-known as a rich sources of secondary metabolites with diverse chemical structures and biological activities. Many small molecules of bioactive compound, often with molecular weight of 500 or below have proven to be extremely valuable for treating diseases. Thousands of compounds have been isolated and characterized, many of which were produced in the commercial scales.

           We have more than 1,000 locally isolated actinomycetes collected from terrestrial and marine soils, as well as plants. Bioactivity of isolated strains were screened primarily against indicator micro-organisms. including human and plant pathogen. Isolates with potent activity were subjected for further screening  for a  potential novel compounds.  At present,  a number of  novel bioactive compounds  were
isolated.

          Cloning and sequencing of gene involved in biosynthesis of g-butyrolactone autoregulator was also investigated. Due to different compounds each strain produces, different gene sequences of regulatory genes were found. The effect on gene dissuption or overexpression are investigated.

Figure 1: Actinomycetes isolated from soils

Figure 2: Example of plant samples  from Num Nao National Park, Phetchabun province


Figure 3: Actinomycetes isolated from plants