ANNUAL REPORT - Department of Biotechnology

facility for experimental TB infection of small animals
(mice and guinea pigs) is in progress.
Mediating immunity to mycobacteria from
secretory antigen activated dendritic cells: In an
effort to identify the mechanisms mediating
suppressor responses from Mycobacterium
tuberculosis secretory Antigen (MTSA) differentiated
and matured Dendritic cells (DCs) (MTSA-DCs) the
roles played by cellular and intracellular factors were
investigated. At the cellular level, stimulation of
MTSA-DCs with mycobacteria resulted in a change
in their polarization. These DCs secreted high levels
of IL-10 and TGF-beta and downmodulated IL-12p40
and IFN-gamma production. Either blocking IL-10 or
TGF-beta or alternatively, conditioning MTSA-DCs
with IFN-gamma and/or IL-12 now induced proinflammatory
responses to mycobacteria. In
addition, cross-talk between MTSA-DCs and T cells
during a cognate interaction resulted in modulation of
surface densities of costimulatory molecules CD80
and CD86 that affected the subsequent quality of Th
responses from these DCs.
Structural and computional biology: The
structural and computational biology group aims at
understanding the structural principles of proteins
using a variety of biophysical (like X-ray
crystallgraphy) and computational tools. The present
focus of research is in the field of malaria and in
membrane protein complexes. The latest
computational tools for modelling large number of
proteins are being used. Finally, In silico screening of
inhibitor libraries against essential malaria parasite
proteins is also in progress.
Plant Biotechnology
The main focus of research is genetic engineering of
cotton, rice and tomato to make them resistant
against insect and fungal pathogens. The group is
working to develop technologies to accelerate the
production of transgenic cotton and rice for durable
resistance against the cotton bollworm complex and
rice yellow stem borer, respectively. Development of
fungal resistant tomato and ginger based on the
expression of AFP-Ca defensin is another area of
major focus. Chloroplast genetic engineering has
several advantages over the conventional nuclear
transformation approaches in terms of high level
expression of foreign proteins. Also the T7 RNA
polymerase based expression developed by this
group has potential to overexpress foreign genes in
a tissue specific manner. Therefore, these
technologies are being applied in the area of
molecular farming.
Plant molecular biology: The group is actively
involved in understanding the mechanisms of plant
adaptation in response to abiotic stresses and
mechanics of DNA replication following virus
invasion. The final aim is to develop abiotic stress
tolerant and virus resistant plants using transgenic
approaches. Functional validation of the genes is
being undertaken using a transgenic approach to
identify the most potential genes for manipulation in
crop plants such as.
Insect resistance: Insecticidal proteins produced by
several soil-dwelling microbes have been studied
with the objective of developing bio-control agents
against crop-pests. The Cry proteins or -endotoxins
produced by Bacillus thuringiensis (Bt) have been
deployed against crop pests in transgenic plants.
The group has identified several bioactive proteins
from the secretome of insect pathogenic bacterium,
Xanthomonas nematophila. The protein caused
aggregation and lysis of larval hemocytes. For the
first time the pore-forming property of pilin subunit of
X. nematophila has been revealed. The gene
encoding a major 60 kDa insecticidal protein from the
culture supernatant of X. nematophila has been
cloned and expressed in E. coli. Group has simulated
putative conditions for development of resistance to
insecticidal protein Cry1Ac in Heliothis armigera. A
stable Cry1Ac resistant population was obtained after
nine generations. Molecular analysis of resistant
insects revealed aberrant Cry1Ac processing by the
resistant population. The Cry1Ac processing
protease has been identified and characterized.
Susceptibility of resistant population against other Bt
proteins that are active against H. armigera is being
evaluated.
199 International Centre for Genetic Engineering and Biotechnology