Abstracts of Papers Presented at the Autumn Meeting of the National Academy of Sciences(USA), Washington, D.C., 24-26 April 1972Source: Proceedings of the National Academy of Sciences of the United States of America,Vol. 69, No. 6 (Jun., 1972), pp. 1647a+1648aPublished by: National Academy of SciencesStable URL: http://www.jstor.org/stable/61454 .

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ABSTRACTS OF PAPERS PRESENTED AT THE ANNUAL MEETING OF THE NATIONAL ACADEMY OF SCIENCES (USA), WASHINGTON, D.C., 24-26 APRIL 1972

Galactose as a marker in tumor transformation

Addition of galactose to tumor cells results in rapid uptake, rapid formation of Gal-i-P and of UDPGal. In contrast, the steps from UDPGal to UDPG and from the latter to G-6-P are practically blocked. This pattern of galactose metabolism is also seen in cultured BHK cells before transformation. However, after transformation by polyoma virus the dis- crepancy between the rates of the first step and those of UDPG metabolism becomes much more extreme. The trans- formed cells show an increased rate of uptake and high galactokinase. UDPGal also accumulates, but the epimerase activity is apparently severely curtailed and rate limiting. The average UDPGal/UDPG ratio was 7.2 for transformed cells as compared with 2.6 for untransformed cells.

In spite of this aggravated choke of the UDPGal-UDPG pathway, transformed cells grow well on a medium con- taining mainly galactose, the glucose present stemming exclusively from the serum added. Much less lactic acid is formed as compared with cultures in which glucose is the only sugar present. Contact appears orderly even in some cases of transformed BHK cells, when galactose replaced glucose as the main source of carbohydrate (Hakomori and Kalckar, unpublished).

Massachusetts General Hospital Harvard Medical School, Boston, Massachusetts 02114

HERMAN M. KALCKAR

SEN-ITIRCH HAKOMORI

University of Washington, School of Public Health, Seattle, Wash. 98105

Physics and public affairs

The following proposal for a new approach to the course in Physics for non-science majors is based on nearly a quarter of a century of teaching such a course to an average of 1000 students each year. After my retirement at the end of the 1969-70 academic year I decided to experiment with a new way of teaching that course (Physics 10), and I believe that iny proposed method, which is to be tried for the first time in the Winter Quarter of 1972, may well be the most innovative and interesting approach to this difficult task.

The clue to this new approach was discovered as a result of my having taught a seminar in the UCLA Public Service Curriculum during the Fall Quarter 1971-72. I agreed to give such a seminar on very short notice and proposed "Science and Public Affairs" as its title. At each session I introduced a topic based on my current readings of such magazines or journals as Bulletin of the Atomic Scientists, Nature (London), Science, Physics Today, Aeronautics and Astronautics, Saturday Review, Harpers and Atlantic Monthly. Included also were reports of Congressional Com- mittees, EOS (American Geophysical Union), Bulletin of the American Meteorological Society, National Academy of

Sciences-National Research Council reports and newsletters and a variety of releases which reach my desk from such sources as my honorary membership in the National Asso- ciation of Science Writers. The most useful of my sources were the Bulletin of the Atomic Scientists, Nature and Science. The final results in the course were far more satisfying to me than has been the case in the past. I ascribe this in great part to the motivation of the 61 students, nearly all of whom were social science juniors and seniors, with a few engi- neering and science majors.

The proposed format for the Physics 10 course will be to spend two of the four lecture hours on rigorous physics, concentrating on one or two subjects which can be related readily to the students' awareness of the world in which they live, 1 hr devoted to topics of current interest taken from the sources that I used in Public Service 100, and I hr to a general discussion.

Approximately 2 weeks after the start of the course I will give a written examination to test the students' knowledge of and opinions regarding topics of current general interest such as the SST, pollution, population control, science policy, technology assessment, etc. A similar test will be given at mid-term and a term paper, on a topic selected by the student and approved by me after a personal interview, will be required at the end of the course.

The class will be limited to 30 students with preference given to juniors, seniors and graduate students who failed to take Physics 10 in the lower division, but who now realize the need for such a course. I plan to have at least two con- sultation hours each day and more if needed. I hope to obtain extra copies of the journals that I have listed so that students can have access to current numbers during the course. I believe that this approach to the teaching of Physics 10 will be useful in other sciences and to other teachers.

JOSEPH KAPLAN

University of California, Los Angeles, Calif. 90024

Analysis suggesting major gene effects in the behavioral population genetics of Drosophila in phototaxic classification mazes

The photophilic phenotype index used in this analysis is t, the number of turns toward the light made by a fly in a Hirsch classification maze, and is thus one less than the final vial number used by Dobzhansky et al. [Proc. Roy. Soc. B. 173, 191-207 (1969), references]. An advantage of t is that a population of flies all of the same genotype char- acterized by the same "maze quotient," MQ, defined as the probability p of making a photophilic decision at each of the m points of choice in the maze, is that t will be distributed in a binomial distribution with mean value mp and variance mp(l - p). The possible existence of such single-genotype populations was suggested by the observation that the

1647a

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1648a National Academy of Sciences Annual Meeting

variances reported by Dobzhansky et al. closely approached the limiting mp(l - p) values expected for a population with a single p-value and that the possibility of more complex behavior patterns, for example, switching from photophilic to photophobic after traversing a portion of the maze, were not emphasized. A graphical method of analyzing final vial dis- tributions is proposed and applied to published distributions. The results are consistent with populations having two or three well-defined values of p. These findings suggest that a search for major gene effects associated with definite prob- abilities of photophilic decisions might contribute to the behavioral population genetics of Drosophila.

W. SHOCKLEY

Stanford University, Stanford, California 94305

The nature of cancer and the chemistry of retine

If irreversible perturbation of regulatory mechanisms disables the cell to maintain its resting balance, cancer results. To understand cancer we have to approach it as a biological and not as a clinical problem, and express our results in terms of energy and entropy, the two factors dominating cell life.

The fuel of life is the energy of the electron of H. Ac- cordingly, the energy supply of the cell can be cut by electron or H acceptors. Ketone aldehydes can act as such. They can also inactivate catalytic SH groups, forming hemimer- captals. Accordingly, as L. G. Egyud and I have shown, they can arrest division reversibly without damaging the cell. Regulations are achieved by changes in entropy which allow enzymes and substrates to meet.

J. A. McLaughlin and the speaker have shown that under normal conditions the cells of multicellular organisms are kept at rest by a hitherto unknown fluorescent yellow dye- stuff, which they called "Retine." This dye is a Schiff base formed by a ketone aldehyde, methylglyoxal, and as yet unidentified nitrogenous substance. A spectroscopic method has been worked out for its quantitative estimation. It is hoped that it will serve as a key to the understanding of cellular equilibria. Its knowledge may lead to a cure and prevention of cancer. It has already led to the synthesis of nontoxic oncostatic agents.

ALBERT SZENT-GY6RGYI

Marine Biological Laboratory, Woods Hole, Massachusetts 02543

The eutrophic value of foods

Foods must furnish (1) fuel, measured in terms of caloric values; and (2) all the raw materials for building and main- taining the cellular and metabolic machinery, which we call the eutrophic value, and for which hitherto there has been no measure.

Eutrophic values cannot be ascertained from consulting food composition tables because only a smattering of the essential information is commonly furnished. A tabulation which includes only a few items-calcium, iron, phosphate, thiamin, riboflavin, niacin, for example-can be seriously misleading, especially if the food has been fortified with some

of these items. Starch, if fortified with these six items, would alone have no appreciable eutrophic value.

Based upon our finding that eggs are an excellent complete food for weanling rats, we have devised and applied a trial method for determining the eutrophic value of foods. If 10% of the calories of a food mixture is cooked egg and the rest carbohydrate, weanling rats will grow slightly for a week or so (using up their reserves) and will thereafter remain alive for our test period but fail to grow or develop. If a food product is substituted for the carbohydrate in this food mixture, the enhanced growth produced as a result of this sub- stitution is a measure of the eutrophic value of the food product. The tentative values we have obtained for about 30 common foods are revealing and instructive.

ROGER J. WILLIAMS JAMES D. HEFFLEY

MAN-LI YEW CHARLES W. BODE

Clayton Foundation Biochemical Institute, University of Texas, Austin, Texas 78712

Some effects of undernutrition on nucleic acid metabolism in developing brain

During early development a series of changes occur in mammalian brain which reflect the net synthesis of nucleic acid and protein. In whole rat brain, DNA content increases linearly until about 21 days of age and then sharply levels off. In the human brain, cell division stops between 12 and 18 months of age. By contrast, RNA and protein content increase progressively until about 100 days of age in rat brain and beyond 2 years in human brain. In addition, activity of DNA polymerase in whole rat brain parallels the rate of cell division (DNA synthesis) during development, while activity of alkaline RNase (pH 7.8) parallels the increase in cellular RNA content (RNA/DNA). This relation- ship of enzyme activity to substrate or product also holds for various regions of the brain.

Malnutrition early in life will impair DNA synthesis, resulting in a reduced number of cells. The reduced rate of DNA synthesis is accompanied by a reduction in DNA polymerase activity. By contrast, although neonatal under- nutrition reduces both RNA and protein content of the brain, RNA synthesis (as measured by incorporation of ['4C]orotic acid into RNA) increases in developing brain, whereas no change occurs in adult brain. RNA degradation also increases in brains of malnourished young animals and is unaffected in brains of adult animals. The increased degradation is accom- panied by a net fall in RNA content and a concomitant increase in activity of alkaline RNase in the immature brain.

These data demonstrate that nucleic acid metabolism differs in mature and immature brain and that malnutrition will affect brain nucleic acid metabolism differently at different ages.

M. WINICK J. A. BRASEL

P. Rosso Institute of Human Nutrition, Columbia University, New York, N.Y. 10032

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