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Biomedical subjects

B Datta

Publications and source records attributed to B Datta.

49 records · Page 3Linked to original sources
PubMed1970

Greater vulnerability of the infecting viral strand of replicative-form deoxyribonucleic acid of bacteriophage phi X174.

Four types of phiX-infected cells of Escherichia coli CR, a thymine-requiring strain of E. coli C, were prepared in which the parental replicative-form deoxyribonucleic acid (RF DNA) was labeled with same specific amounts of bromouracil in (i) both strands, (ii) only the infecting viral strand, (iii) only the complementary strand, and (iv) neither strand. The sensitivity of each type of infected cell toward irradiation by ultraviolet light, visible light, and X rays was measured. The results indicate that a certain amount of radiation damage in the infecting viral strand of the parental RF was more inhibitory to the production of progeny phage than when the damage was in the complementary strand. Similar conclusions were also drawn from "suicide" experiments of the phage-infected complexes containing (32)P of the same specific activity on either strand of the parental RF DNA. The results suggest that the beta decay occurring in the infecting viral strand was more effective in inactivating the plaque-forming ability of the complex.

Bromine↗
PubMedDate not supplied

The age of menarche in classical India.

Data from the writings of Indian legislators during the period between ca. 500 B.C. and A.D. 500 have been used to study menarcheal age among girls born in classical India. As these legislators were concerned mainly with the upper-caste population, it can be presumed that the recordings obtained are only from upper-caste Hindu girls. Throughout the period the age at menarche was about 12 years. A number of legislators considered the best age for conception to be around 16. When these data are compared with those obtained from classical Greece and Rome, the Indian age is found to be about 1-2 years earlier. Comparison of the data from the 19th century and present-day India reveals that the older data are about 0.8-2.2 years earlier when various areas are considered. These results contrast with the downward trend for the age at menarche seen in the industrialized countries during this century.

Age Factors↗