[Keynan Alexander]

KEYNAN, ALEXANDER

Born 1921, Kiev; Ph.D. 1950, Hebrew University: Assoc. Prof. (HU) 1968: Prof. 1977; Emeritus 1990

E-mail: keynan@academy.ac.il

Research Interests:

Molecular mechanisms of cellular growth and differentiation: cryptobiosis-mechanisms of dormancy, and its termination. Biology of spore-forming bacteria. Biological control of insect pests. Science Policy.

Research Projects:

Control of DNA replication in Bacillus. Funding: Private foundations.

The Role of Scientists in International Conflict Resolution. Funding: Carnegie Corporation of New York.

The Future of Research in Israel’s Research Universities – Supported by the Israel Academy of Science.

Abstracts of Current Research:

Control of DNA replication in Bacillus:

The rate of DNA application in bacteria is determined by the rate of initiation at the chromosome origin. In Bacillus subtilis there is evidence that the replication origin is attached to the cytoplasmic membrane, and that this attachment is essential for initiation. We have shown that attachment of DNA to the membrane is cyclic and that DNA, including sequences near the replication origin, becomes attached to the membrane at the beginning of replication and is subsequently released. We have also shown that protein phosphorylation is associated with the initiation of replication in Bacillus subtilis. Factors similar to those controlling the eukaryotic cell cycle may control the phosphorylation and dephosphorylation reactions at initiation of DNA replication in Bacillus subtilis. We are studying these factors and the proteins an

involved in attachment of DNA to the membrane.

Microbial insecticides for control of mosquitos:

Bacillus thuringiensis israelensis (B.t.i.) is a safe and effective control agent for the larvae of disease bearing mosquitoes, especially Aedes aegyptii. However, its usefulness is limited by its brief effective presence in bodies of water where mosquitoes breed In order to overcome this drawback, we have transferred several B.t.i. toxin genes to another insecticidal Bacillus (Bacillus sphaericus, B.sp.) which is longer lasting in the environment of the mosquito larva. Several transformed clones are more toxic to Aedes aegyptii than the wild type B.sp. Further testing will indicate whether the transformants are longer lasting in mosquito larval habits than B.t.i.

KEY WORDS:

biological control, insects, mosquitos; chromosome replication

Recent Publications

Sandler, N. and Keynan, A. (1988) membrane binding and release of Bacillus subtilis DNA as a functin f the cell cycle. J Gen. Microbiol., 134: 1155-1163.

Halvorson, H.O., keynan, A and Kornberg, H.L. ( 1990) Utilization of calcium phosphates for microbial growth at alkaline pH. Soil Biol. Biochem., 22(7): 887-890.

Bar, E., Lieman-Hurwitz, S., Rahamim, E., Keynan, A. and Sandler, N. (1991) Cloning and expression of Bacillus thuringiensis israelensis delta endotoxin DNA in B. sphaericus. J. Invertebr. Pathol., 57: 149-158.

Boschwitz, H., Gofshtein-Gandman, L.,. Halvorson, H.O., Keynan, A. and Milner, Y. (1991). The possible involvement of trypsin-like enzymes in germination of spores of Bacillus cereus T and Bacillus subtilis 168. J. Gen. Microbiol., 137:1145-1153.

Sandler, N. and Keynan, A. (1992) Membrane protein phosphorylation in the Bacillus subtilis cell cycle. FEMS Microbiol. Lett., 95: 241-246.

Bar, E., Sandler, N., Makayoto, M. and Keynan, A. (1998) Expression of chromosomally inserted Bacillus thuringiensis israelensis genes in B. Sphaericus. J. Invertebr. Pathol., 72: 206-213.

Scientific Cooperation, State Conflict, The Role of Scientist in Mitigating International Discord. Allison de Carrero and Alex Keynan, Editor. Annuls of the New York Academy of Sciences, Volume 866 - New York 1998.



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