Sequence and evolution of rhesus monkey alphoid DNA

Analysis of rhesus monkey alphoid DNA suggests that it arose by tandem duplication of an ancestral monomer unit followed by independent variation within two adjacent monomers (one becoming more divergent than the other) before their amplification as a dimer unit to produce tandem arrays. The rhesus monkey alphoid DNA is a tandemly repeated, 343-bp dimer; the consensus dimer is over 98% homologous to the alphoid dimers reported for baboon and bonnet monkey, 81% homologous to the African green monkey alpha monomer, and less than 70% homologous to the more divergent human alphoid DNAs. The consensus dimer consists of two wings (I and II, 172 and 171 bp, respectively) that are only 70% homologous to each other, but share seven regions of exact homology. These same regions are highly conserved among the consensus sequences of the other cercopithecid alphoid DNAs. The three alpha-protein binding sites reported for African green monkey alpha DNA by F. Strauss and A. Varshavsky (Cell 37: 889-901, 1984) occur in wings I and II, but with one site altered in wing I. Two cloned dimer segments are 98% homologous to the consensus, each containing 8 single-base-pair differences within the 343-bp segment. Surprisingly, 37% of these differences occur in regions that are evolutionarily conserved in the alphoid consensus sequences, including the alpha-protein binding sites. Sequence variation in this highly repetitive DNA family may produce unique nucleosomal architectures for different members of an alphoid array. These unique architectures may modulate the evolution of these repetitive DNAs and may produce unique centromeric characteristics in primate chromosomes.

Preliminary X-ray crystallographic and Raman studies on gramicidin S.2HCl

The cyclic decapeptide gramicidin S.2HCl has been crystallized from an aqueous solution containing about 33% (v/v) ethanol. The crystals are suitable for X-ray diffraction studies and are obtained reproducibly. Preliminary X-ray crystallographic studies reveal the crystal to have the orthorhombic space group C222(1), with a = 25.76, b = 35.79, and c = 38.13 A. The asymmetric unit consists of two molecules of gramicidin S.2HCl and several molecules of solvent. This result corresponds closely to that reported by Schmidt et al. (1957, Biochem. J. 65, 744-750). A Raman spectrum of the crystal has been recorded. A strong amide I band at 1670 cm-1 and an amide III band at 1240 cm-1 indicate that gramicidin S has a beta-sheet conformation in its crystal structure. An enhancement of Raman signals from gramicidin S.2HCl adsorbed on Ag sol has been observed.

Survey of abortion providers in Seoul, Korea

A survey of abortion providers in Seoul in late 1977 reveals a threefold increase in the rate of abortion and a greater than threefold rise in the ratio of abortions to live births since 1970. The survey findings also show that the overwhelming proportion of these abortions are performed in private clinics, by obstetrician-gynecologists, during the first trimester. The Seoul figures, which are similar to those of Romania and are higher than those of Japan in the early 1960s, indicate that abortion has contributed substantially to Korea's reduced fertility.