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IN MEMORIAM
DAVID P. BLOCH
Professor David P. Bloch
died October 23, 1986. For 25 years, David was a productive and
revered member of the University community. He excelled both in
research and in teaching, which included courses in freshman biology,
developmental cell biology, and the biology of cancer.
David was born in Chicago on February 10, 1926, and grew
up there. He served in the U.S. Army Air Force in World War II, then
completed an undergraduate degree in chemistry at Northwestern in 1948,
and a PhD in botany and biochemistry at the University of Wisconsin
in 1952. That year he also married Jacqueline deGoumois. They had three
children, Peter, Deirdre, and Elizabeth.
David's most enduring and endearing
characteristic was the boundless–and infectious–enthusiasm
he displayed toward his scientific as well as his social projects. That
enthusiasm remained until the end of his life, and was an inspiration
to his friends and colleagues. Reflecting this sentiment, an admiring
colleague, Harold Kasinsky, wrote this about David's inimitable "style"
and his impact on others:
"Both his colleagues and students
enjoyed Professor Bloch’s wide ranging ideas and his enthusiasm
for science. He encouraged open mindedness in both his freshman
classes in cell and molecular biology and graduate course on molecular
evolution, where he was a particularly effective teacher. He founded
and directed a non-profit Center for the Study of Molecular Evolution
to promote further research in this area. For his research activities
he was honored with a Guggenheim Fellowship and a Career Development
Award from the U.S. Public Health Service."
[Taken from pp. 1095-1097 of Comparative
Spermatology, 20 Years After, B. Baccetti, editor, Raven Press,
New York, 1991.]
In his obituary honoring Professor Bloch,
Dr. Kasinsky went on to point out that David actively expressed his
concern for environmental issues at the local and state levels in Texas
by serving on a task force that looked into the feasibility of recycling
solid wastes in Austin, and by chairing a committee of the Environmental
Quality Board that evaluated the master plan for the city.
David's contributions to his field
were noted as significant from very early on in his career. As a postdoctoral
fellow at Columbia University, he began cytochemical studies which contributed
to an understanding of the role of DNA and histones in spermiogenesis
and early development. With Goodman, he modified the Feulgen procedure
using trichloroacetic acid rather than hydrochloric acid to hydrolyze
DNA. By following Fuelgen staining for DNA he could restain the same
cell type with alkaline fast green for histones using the technique
developed by Alfert and Geschwind in 1953.
David moved to UCLA in 1955, where he
developed sperm basic protein staining techniques using picric acid-eosin
Y and picric acid-bromphenol blue. In these methods, picric acid hydrolyzes
DNA but retains protamines. This allows the visualization of these small
basic proteins in tissues, which is not possible in the alkaline fast
green method where they are removed either by hydrochloric acid or trichloracetic
acid. With Hew, he applied these methods to spermiogenesis in the land
snail Helix aspersa and was able to show a shift from somatic
histones to a stable protamine in the spermatid to protamine in the
mature sperm. He followed this up with cytochemical studies on sperm
basic proteins in the squid Loligo opalescens with its protamine,
the mussel Mytilus edulis with its intermediate sperm proteins,
the frog Rana pipiens with its somatic-like sperm histones, and
the grasshopper Chortophaga viridifasciata with its stable protamine.
In the first three animals he was also successful in purifying the sperm
basic proteins and performing amino acid analyses that showed the validity
of his staining methodology. In 1961 Professor Bloch moved from UCLA
to the botany department of The University of Texas at Austin, where
he remained until he died of cancer in 1986.
David Bloch’s research interest
ranged widely over many aspects of nucleic acid and histone metabolism
in normal and tumor cells. He was especially interested in the flow
cytometric analysis of chromatin, and he set up a computerized flow
systems facility in Austin, modifying his earlier eosin Y staining for
histones to fluorescent measurement by this method. In the latter part
of his career, from 1983 until his death, Professor Bloch and his colleagues
discovered sequence homologies between transfer RNA and the larger ribosomal
RNAs. He convincingly argued that these homologies could reflect a common
origin that may be traceable to archaic RNA molecules existing more
than 3.5 billion years ago, when RNA self-catalysis was more important
than it is now. These findings were published in Biosystems and
in the Proceedings of the National Academy of Sciences, USA,
in 1985. A commentary written by the eminent Roger Lewin in Science
(Vol. 229, p. 1254) highlighted the significance of this work. David's
research on the origins of RNA was also included in a British Broadcasting
Corporation science documentary entitled "Origins."
Clearly, Professor David Bloch made
a very positive impact at The University of Texas as a researcher, as
a teacher, and as a concerned citizen of the Austin community. He is
dearly missed by his colleagues, family, and friends.
<signed>
Larry R. Faulkner,
President
The University of Texas at Austin
<signed>
John R. Durbin, Secretary
The General Faculty
This memorial resolution was prepared by a special committee consisting
of Professors Stanley Roux, Irwin Spear, and Hugh Forrest. |
