Donald J. Nevins
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Professor 129 Asmundson Hall 530-752-1747 Davis, California 95616 FAX: 530-752-9659 email: |
Chair of Symposium Organization Committee
1998 Plant Polysaccharide Symposium
Education
BS California State Polytechnic University, San Luis Obispo, Agronomy, 1959
MS University of California at Davis, Agronomy, 1961
PhD University of California at Davis, Plant Physiology, 1965.
Professional Experience
Postdoctoral Fellow, Chemistry, University of Colorado, 1965-67
Assistant Professor of Botany and Plant Pathology, Iowa State University
1967-71
Associate Professor of Botany and Plant Pathology, Iowa State University
1971-74
Professor of Botany and Plant Pathology, Iowa State University 1974-84
Sabbatical Leave, Department of Biology, Osaka City University, Japan and
Institute of Organic
Chemistry, Stockholm University, Sweden. 1974-75
Professor and Chair, Department of Vegetable Crops 1984-89
Sabbatical Leave, Department of Food Science, Tezukayama College, Biology
Department, Osaka City University, Japan, and Department of Biochemistry,
LaTrobe University, Melbourne Australia
Professor, Department of Vegetable Crops, 1989- present.
Professional Awards
Japanese Society for Promotion of Science Fellow, 1974
Yamada Foundation Fellow, 1990
Research
My research is focused on the analysis and function of complex carbohydrates comprising the plant cell wall. Primarily research is conducted on the biophysical mechanisms accommodating cell extension, the processes that lead to changes in fruit texture during ripening and the development of techniques for the analysis of cell wall polysaccharides. We have had a special interest enzymic mechanisms for the bioconversion of plant materials. The multidisciplinary approaches encompass plant physiology, plant biochemistry, carbohydrate chemistry and biorheology.
We have been responsible for disclosing and evaluating events taking place within the plant cell wall that lead to plant cell growth in grasses. This concept represents one of the major ways to conceptualize how the plant hormone auxin is likely to mediate the controlled relaxation of the wall as a means of regulating expansion without loss of structural integrity. As a consequence of this effort we have also developed a detailed view of the chemical structure of the monocot plant cell wall. Additional compelling evidence in support of a role of glucans and glucan metabolism in growth has been derived from responses of tissues following the administration of specific antibodies. Antibodies generated in response to the introduction of specific wall degrading enzymes into rabbits were capable of suppressing growth in plant bioassays. The current directions in this research is focused on determining the functional and structural characteristics of these proteins and the genes that encode them.
We have also sought to identify the primary structural elements in fruit
cell walls that are responsible for the changes in texture that accompanying
ripening. The work includes the analysis of the rheological properties
of tissues based on stress relaxation measurements. The raw data derived
from measurements is subjected to simulations consistent with would be
expected based on a multicomponent Maxwell model. The results strongly
suggest that an elastic modulus and a viscous component can be identified.
Using transgenic plants in which PG and PME are suppressed by antisense
constructs and rin mutants where PG is augmented by coupling with an ethylene
sensitive promoter we are able to identify the consequences of changes
in gene expression on the rheological properties. The work is being extended
to include other transgenic plants where putative ripening related enzymes
are altered in expression. We have also determined the consequences within
the cell wall of the altered expression of enzymes, providing important
insights into the interpretation of cell wall mutations.
Advances in the knowledge of cell wall structure are dependent on creative
ways to identify specific components and associations. We have sought to
use specific enzymes for this purpose. Two enzymes have been exploited
extensively by our group, one a specific glucanase and the other a specific
xylanase. Both enzymes have the ability to dissociate the cell walls releasing
fragments that provide extensive structural information. As a part of this
effort we have been able to identify a previously unrecognized action pattern
for a polysaccharidase.
Teaching
I teach the General Education course "Plants and People" (PLB 12) designed to provide non majors with an introduction to the role of plants and to provide analytical thinking and creative expression. The topics include an emphasis on ethnobotany, history of cultivation and technology. I teach a freshman seminar to provide students the insights to interpret the way in which the media uses science and an Undergraduate Honors Course. At the graduate level I am one of the instructors for a course designed to cover the Plant Cell Wall.
Selected References
Terasaki, S., N. Sakurai, N. Wada, T. Yamanishi, R. Yamamoto, and D.J. Nevins. 2001. Analysis of the vibration mode of apple tissue using electronic speckle pattern interferometry. Transactions of the ASAE. 44: 1697-1705.
Terasaki, S., Sakurai, N., Yamamoto, R., Wada, N. and Nevins, D.J. 2001. Changes in cell wall polysaccharides of kiwifruit and the viscoelastic properties detected by laser Doppler method. J. Japan Soc. Hort. Sci. 70:572- 580.
Terasaki, S, Wada, N., Sakurai, N., Muramatsu, N., Yamamoto, R. and Nevins, DJ. 2001. Nondestructive measurement of kiwifruit ripeness using a laser Doppler vibrometer. Transactions of the ASAE. 44:81-87.
Yamamoto, R., S. Fujii, E. Tanimoto, and D.J. Nevins. 2000. Computer simulation of osmotic expansion and shrinkage in okra hypocotyl segments. Biorheology 37:213-223.
Inouhe, M., G. Inada, B.R. Thomas and D. Nevins. 2000. Cell wall autolytic activites and distribution of cell wall glucanases in Zea mays L. seedlings. International J. Biological Macromolecules. 27:151-156.
Inouhe, M., K. Hayashi, B.R. Thomas, and D. Nevins. 2000. Exo- and endoglucanases of maize coleoptile cell walls: their interaction and possible regulation. International J. Biological Macromolecules. 27:157-162
Thomas, B.R., G.O. Romero, D. Nevins, R.L. Rodriquez. 2000. New perspectives on the endo-beta glucanases of glycosyl hydrolase Family 17. International J. Biological Macromolecules.27: 139-144.
Thomas, B.R., M. Inouhe, C.R Simmons, and D. Nevins. 2000. Endo-1,3;1,4-B-glucanase from coleoptiles of rice and maize: Role in the regulation of plant growth. International J. Biological Macromolecules. 27:145-149.
Muramatsu, N., N. Sakurai, N. Wada, R. Yamamoto, K. Tanaka, T. Asakura and D. Nevins. 1999. Remote sensing of fruit firmness with a laser Doppler vibrometer. J. American Soc. Horticultural Science 125:120-127
Ma, J. F., R. Yamamoto, D.J. Nevins, H. Matsumoto, and P. Brown. 1999. Aluminum binding in the epidermis cell wall inhibits cell elongation of okra hypocotyls. Plant and Cell Physiol. 40:549-556.
Inouhe, M, K. Hayashi, and D. Nevins. 1999. Polypeptide characteristics and immunological properties of exo- and endoglucanases purified from maize coleoptile cell walls. J. Plant Physiology 154:334-340.