Structure of human luteinizing hormone alpha subunit.

Structural studies have substantiated the concept that the glycoprotein hormones consist of a "common" alpha subunit and "hormone-specific" beta subunit. Despite this, consensus is still lacking concerning certain portions of the amino acid sequences, including alignment of residues 81--82 in the alpha subunit. We have carried out sequence analysis of the alpha subunit of human luteinizing hormone (hLH) to clarify the assignment of these residues and to examine further the nature of the amino-terminal heterogeneity found among the different alpha subunits.

Microbial indicators of oil-rich salt marsh sediments.

Selected microbial parameters were monitored in sediments from a pristine and an oil-field salt marsh. Although numbers of hydrocarbonoclastic bacteria and fungi were significantly greater in the oil field, the values did not show a strong correlation with levels of hydrocarbons (r = 0.43 and r = 0.

Early Pliocene sediments and fossils from the northern Kenya Rift Valley.

Mammalian fossils, which include the tooth of an early hominid, have been recovered from the newly mapped Ngorora Formation in the Baringo District. Preliminary dating suggests that this formation is aged between 9 and 12 million years, and the new finds thus help to span a ten million year gap in the fossil mammal record in Africa south of the Sahara.

Effect of repeated irradiation on various characteristics of Salmonella.

Four Salmonella serotypes which had been subjected to either 15 or 20 cycles of irradiation and subculture were examined for possible changes induced by the treatment. With three serotypes virulence remained unchanged, and with one serotype a reduction had occurred. A few minor changes in the biochemical characteristics occurred in some instances, but with all cultures the serological property was affected to some extent.

Development of radiation resistance in Salmonella cultures.

Cultures of Salmonella subjected to repeated cycles of gamma-irradiation and subculture developed radiation resistance sooner at a low cycling dose ( approximately 1% survival) compared to a high cycling dose ( approximately 0.001% survival). Radioresistant cells in a population of radiosensitive cells of Salmonella newport or S.