Research

Thrust areas of development.
  • Large scale gene sequencing
  • Plant transformation for pharmaceutical proteins and agronomic traits 
  • DNA barcoding of plants and animals 
  • Biodiesel production using algae 
  • Metabolic Engineering by RNAi 
  • Molecular diagnosis and Genetic counseling  

Plant transformation for pharmaceutical protein and agronomic traits
Expression of human GAD65 in for Type I Diabetes 
Dr. M. Parani, P. Rathinasabapathi 
Plants are used as system to produce the recombinant proteins, especially the therapeutic important protein like antibodies, vaccines. Plant based system has the major advantage in foreign protein production in term of the equipment and cost needed, large production of foreign protein in plants is easier than the animal and other eukaryotic cells. Plants are become more suitable when the proteins are need for post-translation modification which very common for the protein from eukaryotic cell. Expression of therapeutic protein in edible fruits like banana, tomato has another advantage that these transgenic fruits can be used as the vaccine and these eatable vaccines are known as edible vaccine. In this study, we tried to develop the transgenic tomato which expresses the human Glutamic Acid Decarboxylase 65 (GAD 65). Glutamic acid decarboxylase acts as an autoantigen which leads to the self destruction of pancreatic cells by immune system and to the development of Type I Diabetes. Clinical trials show that, administration of GAD to the patients delays the onset of Type I Diabetes. Type I diabetes is predominant in the children of age less than 12 years. In this study, we express the human Glutamic Acid Decarboxylase (GAD) in Solanum Lycopersicum (tomato) fruit, that it can be used as an edible vaccine against Type I diabetes. 

Expression of human PDGF for Diabetic Foot ulcer
Dr. M. Parani
Platelet derived growth factor, a 30 kDa protein composed of disulfide linked homo-hetero dimers of A and B polypeptide chains and act as major mitogen in human blood serum. It promotes the proliferation of mesenchymal cells, specifically fibroblasts and glial cells) and supports angiogenesis (Heldin and Westermark, 1999). The A and B chains are synthesized as precursors that after dimerization undergo proteolytic processing, in their mature parts and they show 60% aminoacid identity with a perfect conservation of all eight cysteine residues (Josephs et al., 1984; Betsholtz et al., 1986). In human Platelet derived growth factor-BB (hPDGF-BB) dimer, six of cysteine residues were involved in intra-chain disulfide bonds (Oefner et al., 1992) and remaining two cysteine residues linked with two chains were not involved in dimer formation or bio-activity (Kenney et al., 1994). Recombinant hPDGF-BB is well proved to cure diabetic foot ulcers. Diabetic neuropathic ulcers develop among the 15% of individuals having diabetes which shows slow healing rate and resistance to other treatments. Currently, in preclinical trials the therapeutic recombinant hPDGF-BB in the form of gel (becaplermin) which is approved to treat high pressure ulcers (Kallianinen et al., 2000), non-healing wounds in irradiated tissue (Hom and Manivel 2003) which promotes periodontal tissue damage effective in enhancing the repair of musculoskeletal and maxillofacial disorders (Jeffery et al., 1996; Cooke et al., 2006) 

Great efforts have been made to yield a high amount of recombinant hPDGF-BB protein for therapeutic application. Recently, the recombinant hPDGF-BB has been expressed in E.coli (Hoppe et al., 1988), in Chinese hamster ovary (CHO) cells (Arne ostman et al., 1992) and also in vaccinia virus (Jeffery et al., 1996). Production of recombinant therapeutic protein in plants is more attractive for its low cost, easy scale up and for efficient harvesting, storing and processing (Whitelam et al., 1993). It is well known that frequency of codon between the gene of interest and the host of expression will affect expression level of heterologous protein level. Codon optimization has been used to improve the heterologous protein expression in living organism by increasing the translational efficiency of heterologous gene (Gustafsson et al., 2004; Mechold et al., 2005). Many reports reveals that addition of the KDEL sequence to the C- terminus of the recombinant protein increase the accumulation of protein in ER derived storage vacuoles, without altering the protein natural structure or its biological function (Richter et al.,2000). 

In the present study, we have expressed the recombinant hPDGF- BB (rhPDGF-BB) in tobacco plants and further; the biological activity of rhPDGF-BB in fibroblast cells was examined. Expression of hPDGF- BB in plant system has not been reported till now. For the first time an attempt has been made to express the therapeutic value of hPDGF- BB protein in tobacco plant. The codon optimized hPDGF- BB gene along with tetrapeptide tags Lys-Asp-Glu-Leu (KDEL) at carboxy–terminal end to retained the protein in endoplasmic reticulum is expressed under the control of double–CaMV35S promoter. The stable transformation is mediated by Agrobacterium and the biological activity of recombinant protein was analyzed by cell proliferation, in vitro wound healing and chemotaxis assay. 

Cancer and Stem cell biology
Dr. Devi. A
In recent years, scientists have discovered a wide array of stem cells that have unique capabilities to self-renew, grow indefinitely, and differentiate or develop into multiple types of cells and tissues. Cancer stem cells (CSCs) have been defined as a unique subpopulation in tumors that possess the ability to initiate tumor growth and sustain tumor self-renewal. Cancer stem cells may explain the cellular heterogeneity seen in tumors, as well as cancer relapses often seen after treatment. The hypothesis about CSCs assumes that these cells may arise from stem cells or early progenitor cells, by accumulation of genetic modifications or epigenetic alterations. Given their potential role in tumorigenesis, CSCs are important targets for research and therapy. 

Embryonic and adult stem cells express genes which have been shown to be essential in maintaining the pluripotency and self-renewing capacity of these cells. Analysing the expression of stem cell markers in cancer cells and stem cells would pave way to understand the relationship between cancer cells and stem cells. The role of these proteins in carcinogenesis and progression of cancer can be detected. 

Whole Genome and Transcriptome Sequencing 
Dr. N. Purushothaman
Genome is the total DNA content of an organism. Transcriptome is the total content of the expressed genes from an organism. The complete decoding of the genome and transcriptome of every organism such as animals, plants, algae and bacteria is essential to study the genetics of an organism and to manipulate the organisms genetically to benefit the world. Sequencing of human genome is much easier now with the new sequencing technologies and we are actively engaged in it. The total plant genome includes three separate genomes namely nuclear, chloroplast and mitochondria. The size of the each genome varies between 15kb to 16000Mb and more. Initially, sequencing of the bigger genomes was not possible due to cost and time. But now, this is feasible with the third generation sequencing technologies. Our group is actively involved in the whole genome, transcriptome sequencing and analysis in human, plants, bacteria and algae using newest sequencing technologies. 

RNAi Mediated Metabolic Engineering in Plants 

Dr. M. Parani, Rexarunraj .A 
Plants offer a useful system for expressing therapeutic proteins. The therapeutic proteins produced by a plant rich in toxic secondary metabolites is not conducive for feed trials. Moreover production of low nicotine tobacco plants would provide low risk tobacco for commercial purpose. Nicotine is the major alkaloid in tobacco plants and its percentage in leaf vary from 0.6-9.0% in Nicotiana tobaccum to 18.76% in Nicotiana rustica. In this scenario the production of low nicotine tobacco for the expression of heterologous protein will be a breakthrough technology. Putrescine N-methyltransferase (PMT, EC 2.1.1.53) catalyzes the first committed step in the nicotine biosynthesis pathway in roots of tobacco. The study involves silencing of Putrescine N - Methyl Transferase gene to produce nicotine free tobacco. The siRNA construct for the gene was cloned and tobacco plants were transformed by Agrobacterium mediated transformation. The expression level of Putrescine N-methyltransferase and the accumulation of nicotine in various parts of the plant are being studied. 


Biodiesel production using microalgae 

Dr.M.Ramya 

Fatty acid methyl ester originating from vegetable oil and animal fat is known as biodiesel. Microalgae has been recognized as a good source for the production of biodiesel because of higher photosynthetic efficiency, more biomass production, rapid growth rate, and it has the ability to fix more atmospheric CO2 from the variety of sources. Many microalgal species have the ability to accumulate large amount of lipids (20-50% of total body weight). (Chisti, 2007). The potential applications of microalgae such as biofuel production, vitamins, carotenoids and polyunsaturated fatty acids (Liam and Philip, 2009). 

The following processes were essential for biodiesel production from microalgae including strain selection, cultivation, harvesting and lipid extraction. Cell disruption plays a major role to increase the lipid extraction efficiency. Lipid extraction was carried out from Chlorella vulgaris, Botryococcus sp and Scenedesmus sp using microwave method and showed more lipid extraction efficiency (Lee et al. 2010). Sonication method has been widely used to disrupt the microorganism and it has the ability to produce large amount of eicosapentaenoic esters from microalgae. Sonication method was chosen as efficient method for lipid extraction from Nostoc sp. (Prabakaran and Ravindran, 2011). During sonication, high frequency sonic waves will generate higher atmospheric pressure to disrupt the cell wall. (Lee et al., 1998 and Belabi et al. 2000). 

In our study, we have collected 50 fresh water samples from different places of Tamil Nadu, India. The samples were inoculated into common fresh water media (BBM, BG -11 and CFTRI) for pure strain isolation. Pure strain isolation was carried out using serial dilution method and strains were identified based on the morphological and molecular characterization. The identified strains were Chlorella sp, Chlorella sorokiniana, Scenedesmus sp, Scenedesmus dimorphus, Scenedesmus obliqus, Scenedesmus bajacalifornicus, Chlorococcum sp, Oedogonium sp, Ankistrodesmus stipitatus, and Stoichiocococcus bacillaris. Eight different cell disruption methods were compared for lipid extraction of microalgae. Among that, sonication was chosen as the most effective, simple and easy method for effective lipid extraction. The same sonication method was applied for lipid extraction from the isolated strains. The lipid content percentage was found to be 14.2%, 29%. 36% and 19.3% for Chlorella sorokiniana, Stoichiocococcus bacillary, Ankistrodesmus stipitatus and Chlorella sp. From the isolated strains lipid content percentage would be compared and high oil content containing microalgal strains would be selected for media optimization and further biodiesel production.