184 AISnSTJAL REPORT SIVITTHSONIAN INSTITUTION, 19 64 



of station operations; and Col. Olcott M. Brown (now serving as con- 

 sultant), station coordinator of Moonwatch. 



Consultants at the Observatory during the year were Dr. Pol 

 Swings, Dr. John A. Wood, Sir A. C. B. Lovell, Mr. Thomas C. 

 Marvin, Dr. George Murray, and Dr. Om P. Rustgi. 



On June 30, 1964, the Observatory employed 404 persons. 



DIVISION OF RADIATION AND ORGANISMS 

 Prepared by W. H. Klein, Chief of the Division 



Research of the Division of Radiation and Organisms is directed 

 toward those areas of investigation in which radiation affects or 

 controls, directly and indirectly, the functions of living organisms. 

 Specific areas which have been investigated intensively by the division 

 include the control of regulatory mechanisms by nonionizing radiation 

 such as photomorphogenesis, phototropism, the induction of photo- 

 synthetic activity and the interaction of ionizing radiation with syn- 

 thetic and morphological systems, vSuch as the effects of X-rays and 

 gamma rays at the cellular and subcellular levels. Research has con- 

 tinued on the storage of energy in and synthesis of macromolecules 

 in such diverse systems as higher plants and marine algae. The 

 service activity of the carbon-dating laboratory has been expanded, 

 and the division also conducts basic research in developing and ex- 

 tending dating techniques. 



Investigation of the mechanism by which chloramphenicol, an anti- 

 biotic protein inhibitor, inhibits light-dependent development of 

 photosynthetic activity of bean leaves has been continued. The 

 chloramphenicol prevents formation of a normal chloroplast struc- 

 ture, the absence of which is correlated with a larger percentage of 

 water-soluble plastid protein. Investigations by serological tech- 

 niques of differences between water-soluble proteins of plastids from 

 treated and untreated leaves are in progress. The results indicate 

 that there are different proteins in the soluble fractions from the 

 two sources. The plastids from treated and untreated leaves differ 

 in ability to generate antibodies, indicating differences in arrange- 

 ment of proteins in the two types of plastids. 



Although diatoms grown in the dark synthesize photosynthetic 

 pigments, less chlorophyll is produced than in the light. Some evi- 

 dence indicating a difference in the ratio of chlorophylls to carot- 

 enoids in light- and dark-grown cells has been obtained. Changes 

 in the absorption spectrum of diatom cells brought about by heating 

 also occur on treatment with chemicals known to bring about changes 

 in the configuration of protein molecules. Studies on the changes 

 of the absorption spectra of the diatom cells that occur on heating 



