Research Statement





Research Interests | 

The field of molecular pharming is still in its early stages and further improvement of this discipline requires collaborative expertise from various molecular biology fields. My main research interest lies on actively participating in plant molecular biology studies, mainly aimed at understanding molecular mechanisms and bring the expertise towards production of biopharmaceuticals in plants, plant cell suspension cultures, Chlamydomonas and yeast (molecular pharming). In addition to molecular pharming, I have strong interest in biofuel production in plants and yeast and also bio-fertilizer production using genetically modified plant symbiotic organisms.

 

I’m also extremely interested in Synthetic Biology research and my ambition is to design synthetic pathways and develop synthetic products (medicines and other useful products) in plants using all the expertise of cloning, transgenic research, molecular biology, synthetic biology, biochemistry and pharmacy etc.

 

In addition to above interests, I also have special interest and research idea in using CRISPR/Cas9 technology embedded viruses to knockout bacterial antibiotic resistant genes so that bacteria infected with these engineered viruses would be susceptible to antibiotics.

 

My future work will continue along the lines of synthetic biology and molecular pharming. 





Past Research | 

High yield production of apoplast-directed human adenosine deaminase in transgenic tobacco BY-2 cell suspensions   Singhabahu et al., (2015).

 

Adenosine deaminase (ADA) deficiency, where a deleterious mutation in the ADA gene of patients results in a dysfunctional immune system, is ultimately caused by an absence of ADA. Over the last 25 years the disease has been treated with PEG-ADA, made from purified bovine ADA coupled with polyethylene glycol (PEG). However, it is thought that an enzyme replacement therapy protocol based on recombinant human ADA would probably be a more effective treatment. With this end in mind, a human ADA cDNA was inserted into plant expression vectors used to transform tobacco plant cell suspensions. Transgenic calli expressing constructs containing apoplast-directing signals showed significantly higher levels of recombinant ADA expression than calli transformed with cytosolic constructs. The most significant ADA activities, however, were measured in the media of transgenic cell suspensions prepared from high expressing transformed calli: where incorporation of a signal for arabinogalactan addition to ADA led to a recombinant protein yield of approximately 16 mg L−1, a 336-fold increase over ADA produced by cell suspensions transformed with a cytosolic construct.

 

Expression of functional human adenosine deaminase in tobacco plants Singhabahu et al., (2013)

 

An inherited disorder, adenosine deaminase deficiency is a form of severe combined immunodeficiency, which is ultimately caused by an absence of adenosine deaminase (ADA), a key enzyme of the purine salvage pathway. The absence of ADA-activity in sufferers eventually results in a dysfunctional immune system due to the build-up of toxic metabolites. To date, this has been treated with mixed success, using PEG-ADA, made from purified bovine ADA coupled to polyethylene glycol. It is likely, however, that an enzyme replacement therapy protocol based on recombinant human ADA would be a more effective treatment for this disease. Therefore, as a preliminary step to produce biologically active human ADA in transgenic tobacco plants a human ADA cDNA has been inserted into a plant expression vector under the control of the CaMV 35S promoter and both human and TMV 5′ UTR control regions. Plant vector expression constructs have been used to transform tobacco plants via Agrobacterium-mediated transformation. Genomic DNA, RNA and protein blot analyses have demonstrated the integration of the cDNA construct into the plant nuclear genome and the expression of recombinant ADA mRNA and protein in transgenic tobacco leaves. Western blot analysis has also revealed that human and recombinant ADA have a similar size of approximately 41 kDa. ADA-specific activities of between 0.001 and 0.003 units per mg total soluble protein were measured in crude extracts isolated from transformed tobacco plant leaves.





Current Research | 

Production of salt tolerant rice plants

 

I’m currently working as a post-doctoral scientist (leader of Synthetic Biology team) at Human Genetics Unit, Faculty of Medicine, University of Colombo, Sri Lanka and conducting research on developing novel plant synthetic biology platforms to increase salinity tolerance through changing root architecture and signal transduction pathways in view of acquiring U.S patent on novel findings.

 

Next-generation sequencing of indigenous plant species

 

Next generation sequencing of a Sri Lankan salt tolerant rice variety ‘Godawee’ using Illumina Miseq platform to identify unique SNPs, InDels and novel regulatory elements in the genes involved in salt tolerant pathway.





Future Research Interests | 

My short-term goal is to develop transgenic salt tolerant plants by changing salt tolerant pathways through synthetic biology techniques.

 

My longer-term goals are focused on the development of CRISPR/Cas9 technology embedded modified viruses as drugs or vaccines to alleviate bacterial resistance to antibiotics through targeted modification of genes involved in antibiotic resistance in bacteria.

 

Further to above goals, one of my longer-term goals also include change in biochemical pathways of organisms such as plant cells, yeast or Chlamydomonas, in order to produce medicines/biopharmaceuticals through synthetic biology platforms.