Long-acting contraceptive agents: norethisterone esters of monoalkenyl and monoalkynyl acids

The synthesis of nine new esters of norethisterone (17 alpha-ethynyl-17 beta-hydroxyestr-4-en-3-one) is described, with the esterifying acids bearing an acetylenic or olefinic function in a chain of eight or nine carbon atoms, for evaluation as long-acting contraceptive agents.     

Immunological studies of Escherichia coli mutants lacking one or two ribosomal proteins

Summary A battery of immunological tests were used to investigate mutants which had been determined as lacking one or two ribosomal proteins on the basis of two-dimensional polyacrylamide gels. Proteins which were confirmed as missing from the ribosome in one or more mutants were large subunit proteins L1, L15, L19, L24, L27, L28, L30 and L33 and small subunit proteins S1, S9, S17 and S20. Cross-reacting material (CRM) was also absent from the post-ribosomal supernatant except in the case of protein S1. Since mutants lacking protein L11 have been previously described, any one of 13 of the 52 ribosomal proteins can be missing. None of these 13 proteins, except S1, can therefore have an indispensable role in ribosome function or assembly. In several mutants in which a protein was not missing but altered, it was present as several moieties of differing charge and size.     

Induction and rapid repair of sister-chromatid exchanges in multiple murine tissues in vivo by diepoxybutane

Sister-chromatid exchange (SCE) induction by the direct-acting bifunctional carcinogen, diepoxybutane (DEB), was investigated in multiple tissues in vivo. The log-log dose SCE response relationship was found to be parallel to that previously reported for DEB induction of lung adenomas. However, the SCE assay is approximately 20 times as sensitive in detecting genotoxic effects of DEB than indicated by the lung adenoma assay. Examination of second and third division cells following various treatment protocols revealed that regardless of the nature of initially induced lesions, they are rapidly repaired with no evidence of persistence beyond 1 cell cycle.     

In vitro and in vivo regulation of chloroplast glyceraldehydes-3-phosphate dehydrogenase isozymes from Chenopodium rubrum. I. Purification and properties of isozymes

Chloroplast glyceraldehyde-3-phosphate dehydrogenase (GPD, EC 1.2.1.13) was purified from leaves of Chenopodium rubrum L. Aggregated (≥ 10⁶) and disaggregated (165 × 10³) molecular weight forms were obtained by gel filtration in the presence of NAD⁺ and NADP⁺, respectively. The disaggregated enzyme was separated into two isozymes by inverse ammonium sulphate gradient solubilization: "NADP-GPD I" was homotetrameric (subunit molecular weight 39 × 10³); "NADP-GPD II" was heterotetrameric (subunit molecular weights 39 × 10³ and 43 × 10³). Isoelectric focusing of the isozymes, both aggregated and disaggregated, revealed two isoelectric forms in each case, at 4.3 and 7.7. Chloroplast GPD was "NADP-suppressed" in crude extracts due to partial oxidation, incubation with dithioerythritol restored full activity.     

High recombination between the breakpoint of a reciprocal translocation in rye (Secale cereale L.) and an interstitially located gene

Summary The recombination fraction between the interstitially located gene an and interchange 303 of rye was found to be 0.244±0.038 in a test cross using the translocation as the male parent. In first metaphase translocation configurations in pollen mother cells of the same plant, the chiasma frequency between an and the translocation breakpoint was found to be significantly more than twice the recombination fraction. Recombination was concluded to be masked by a difference in the alternate frequency between configurations without interstitial chiasmata and configurations with interstitial chiasmata, the effect of the first type being of major importance. Random centromere orientation of translocation multivalents with interstitial chiasmata was concluded to be a realistic assumption. The exceptionally high recombination between an and translocation 303 is discussed. Consideration is also given to the use of interchanges in the establishment of a marker's chromosomal position, and to the use of translocation chromosomes in balanced systems for hybrid breeding purposes.     

Ultrastructural and biological characterization of human choroid cell cultures transformed by Simian Virus 40

A human diploid cell line of choroid origin was isolated from the retrouveal portion of an enucleated eye and designated HC. After 10 passages, when the proliferative capacity of HC cells decreased, they were infected and transformed by Simian Virus 40 (SV40). A proliferating long-term cultured cell line designated HC/SV40 was established and it has been maintained as monolayer for more than 100 passages so far. The two cell lines, HC and HC/SV40, were compared for growth characteristics, capacity to form colonies in soft agar, presence of nuclear T-antigen, and ultrastructure. Cytogenetic analysis was also performed to determine the presence of chromosomal aberrations due to the permanent viral transformation of the cell line. The results indicate that HC/SV40 should be considered the transformed counterparts of HC cells because they are morphologically similar to the latter but can grow in soft agar, possess T-antigen, and show a pattern of karyotypic changes similar to that induced by SV40 in human fibroblasts. The choroid origin of HC and HC/SV40 cell lines was confirmed by the presence, in their cytoplasm, of typical electron dense granules. Their neural origin will make these cell lines very useful for neuropharmacological and differentiation studies.     

Relationship of the replication and incompatibility genes of an IncFVI haemolysin plasmid with other F-like haemolysin plasmids

The replication and incompatibility region of the IncFVI plasmid pSU502 has been isolated by in vitro DNA manipulation as part of a 12.6 kb plasmid, denominated pSU503. Plasmid pSU503 was strongly incompatible with its parental plasmid, pSU1, but was fully compatible with the haemolytic plasmids pSU316 (IncFIII/IV), pHly152 (IncI2) and pSU233 (Inc-pSU233). Furthermore, the 6.9 kb EcoRI fragment of pSU503 which carries the replication and incompatibility determinants of pSU1 did not show any detectable homology (less than 70%) with any of the haemolysin-determining plasmids with which it is compatible. Thus, homologous haemolysin determinants have become linked to apparently unrelated replicons.     

Rapid,gregarious settlement of the larvae of the marine echiuran Urechis caupo Fisher & MacGinitie 1928

Larvae of Urechis caupo Fisher & MacGinitie, reared in the laboratory, were exposed to potential settlement stimuli, including natural sediment from adult burrows, and “scent” obtained from the skin of adult animals. Competent larvae settled rapidly and specifically in response to adult burrow sediment when compared with their responses to other natural and abiotic sediments. Larvae also responded specifically to chemical “scent” from adult animals when the “scent” of another echiuran worm, Listriolobus pelodes Fisher served as a control. Larval responses to chemical “scent” were as great as their responses to natural burrow sediment. Hence, it is likely that larvae settle gregariously in nature in response to “scent” on sediment grains of adult burrows. The chemical “scent” had a molecular weight between ≈3500 and 14000 daltons, as determined by dialysis. It quickly lost its effectiveness in promoting settlement after it was heated to 80 °C, but was relatively stable at ambient ocean temperatures, retaining its effectiveness for several days. It was soluble in sea water. However, larvae did not respond to the chemical “scent”, unless it was adsorbed onto a surface. Purely tactile stimuli, such as the shape, texture, and size-distribution of particles, were not important settlement cues during these experiments.