52 Thorncliffe Park Drive, Apt. 308
Toronto, Ontario M4H 1K5
e-mail: bcgeorge at interlog.com
Career Interest: Research and Development in Plant Biochemistry and Plant
Ph.D. Department of Plant Sciences, Madurai Kamaraj University, India.
Submitted October 1994 Awarded Nov. 1996
Thesis Title: Stress Tolerance in Photosynthetic Systems; Its Biology and
Advisor : Dr. A. Gnanam
Master of Science in Bio-Chemistry Apr. 1988, University of Madras,
Bachelor of Science in Bio-Chemistry Apr. 1986, University of Madras,
Special Training: Demonstrated and Conducted experiments in Plant Molecular
Biology as a team member for the Short term training course on Structure,
Function and Molecular Biology of Chloroplasts, organized by the School of
Biological Sciences, Madurai Kamaraj University, India in May 1991.
Participated in the short course on Methods in Plant Molecular Biology,
organized by International centre for Genetic Engineering and Biotechnology,
New Delhi, India in Aug. 1989.
Senior Research Fellowship awarded by University Grants Commission, India,
Mar. 1993- Feb. 1995
Junior Research Fellowship awarded by University Grants Commission, India,
Mar. 1990- Feb. 1993
Junior Research Fellowship awarded by USDA for the PL480 Phase II project,
Nov. 1988- Feb. 1990
Isolation and Purification of total DNA and chloroplast DNA from plants,
isolation of plasmid DNA, agarose gel electrophoresis, restriction analysis,
Radioactive labeling of DNA, Southern Hybridization analysis, Isolation and
Purification of plant proteins, SDS - Polyacrylamide gel electrophoresis,
invitro translation, Western Blot analysis, Isolation of total RNA from
plants, purification of mRNA, oligodT cellulose column chromatography,
alkaline and formaldehyde gel electrophoresis, isolation of intact
chloroplast, Sucrose and Percoll density gradient centrifugation, gel
filtration, invitro protein synthesis, cell culture, transformation of
plants using A.tumefaciens and invitro propagation of plants.
1. Mariamma M, Muthukumar B, Veluthambi K. and Gnanam A. (1997) Effects of
high temperature stress on the expression of low molecular weight heat
proteins in rice leaves. J.Plant Physiol. 151:763-765.
2. Mariamma M, Muthukumar B. and Gnanam A. (1997) Thermotolerance and
effect of heat shock on the stability of the ATPase enzyme in rice. J.Plant
3. Muthukumar B, Mariamma M, Veluthambi K. and Gnanam A. (1996) Genetic
transformation of cotyledon explants of cowpea (Vigna unguiculata Walp)
using A. tumefaciens. Plant Cell Reports 15(12) : 980-985.
4. Muthukumar B, Mariamma M, and Gnanam A. (1995) Regeneration of plants
from primary leaves of cowpea. PCTOC 42(2) : 153-155.
5. Gnanam A, Muthukumar B, Mariamma M and Veluthambi K (1995) Genetic
transformation of cowpea by A. tumefaciens using cotyledons as explants,
Vol.III Proceedings of the Xth International Photosynthesis Congress
6. Muthukumar B, Mariamma M and Gnanam A. (1996) Agrobacterium mediated
transformation and regeneration of transgenic plants from epicotyl explants
of cowpea. Manuscript submitted.
7. Muthukumar B, Mariamma M, Gnanam A. (1999) Regeneration of plants from
nodal explants of cowpea. Manuscript submitted.
Research Work: Elevated soil temperature constitute a major limitation to
successful crop production of tropical plants such as rice, which is an
important crop. The objective of this study was to characterize the heat
shock response in rice leaves concentrating on the expression of heat shock
genes at the level of translation in particular.
Characterization of the heat shock response in rice leaves under various
conditions was followed.
Rapid decline in cell viability and loss in the plasma membrane activity
were observed in rice leaves subjected to rapid heat shock. In contrast,
rice leaves pretreated at a mild heat shock induced tolerance to survive
better at higher temperature and the activity of the plasma membrane also
was not much affected.
The HSP enriched fraction from rice was found to be very effective in
protecting the plasma membrane from the direct effects of heat . The
stability of the plasma membrane bound Mg2+ - K+ ATPase in rice was found
to be proportional to the amount of post-ribosomal HSP fraction added.
Gradual exposure to a high temperature elicited a comparatively better
response than the application of a sudden heat shock and heat shock
proteins were found to be synthesized even at a very high temperature of
45°C after a preincubation at a slightly lower temperature of 42.5°C which
was not possible upon a sudden heat shock.
The decline in the synthesis of HSPs in rice leaves was not co-ordinate.
Low molecular weight HSPs and their mRNAs were more stable and have a higher
half life than that in the high molecularweight range.
Antibiotic studies indicated that the HSPs in rice are synthesized on
cytoplasmic ribosomes and not in the organelles and heavy metals like
Arsenite and Cadmium were found to mimic the heat shock response in rice
leaves. Etiolated rice leaves also synthesized HSPs in a temperature
dependent manner as in green leaves.
Homologous genes and their transcripts to pea and soybean low molecular
weight HSPs were identified in rice by Southern and Northern analysis.
Cross reaction of rice HSPs were observed with pea low molecular weight
antibodies on Western analysis. Homologues to pea Class I Low molecular
weight HSP and the pea chloroplast localized low molecular weight HSP were
identified in rice leaves.
Additional Research Interest: Regeneration and Transformation studies in
legumes. Helped in the establishment of regeneration protocols for
regeneration of cowpea, rice and peanut from different explants and in the
successful transformation of cowpea and peanut.