The influence of age on fecal steroid hormone levels in male Budongo Forest chimpanzees (Pan troglodytes schweinfurthii)

Potential interactions between age and endocrinological functioning have been understudied in wild ape populations. Therefore, we examined the relationship between age and the secretion of androgens and glucocorticoids in 15 juvenile, subadult, and adult male chimpanzees (Pan troglodytes schweinfurthii) free ranging in the Budongo Forest of Uganda. One hundred and nine fecal samples were opportunistically collected, between 07:30 and 13:30 hr, during the wet season. Fecal samples were preserved, by oven drying, and steroid content extracted before radioimmunoassay for dehydroepiandrosterone-sulfate (DHEA-S), testosterone (TEST), cortisol (CORT), and corticosterone (CCT). Employing indexes of age as predictive factors, linear mixed-effects modeling and non-parametric statistical comparisons of fecal steroid levels were conducted. Age was observed to significantly influence the production of both glucocorticoids and androgens in male Budongo Forest chimpanzees. Basically, whereas TEST and CORT increased, DHEA-S and CCT levels slightly declined as animals matured.     

Gonadal development in hermaphrodite mice

Summary The genetic background and morphology of spontaneous mosaic hermaphrodites of mice have been described. Presented in the formal symposium on Sexual Differentiation in Vitro and in Vivo at the 29th Annual Meeting of the Tissue Culture Association, Denver, Colorado, June 4–8. 1978. This work was supported by Grant HD 04083 from the National Institute of Child Health and Human Development.     

An unusual chromosome system in a leafhopper (Homoptera auchenorrhyncha)

An unidentified species of the genus Austroagalloides is shown to have 7_II+1_IV instead of the normal 11_II+XO configuration at metaphase I of meiosis in males. The quadrivalent manifests two types of pairing which ensures regular disjunction; normal chiasma-type pairing and distance pairing. It is suggested that the 7_II+1_IV form is derived from the 11_II+XO form by a series of fusions.     

Sulfur-Deficient Transfer Ribonucleic Acid in a Cysteine-Requiring, “Relaxed” Mutant of Escherichia coli

A cysteine-requiring mutant of the parent strain Escherichia coli Hfr Cavalli (RC(rel), Met(-), lambda) has been isolated. The mutant was selected by using replica plating after mutagenesis by N-methyl-N'-nitro-N-nitrosoguanidine. The mutation appears to be in the gene for sulfite reductase, since the mutant could utilize sulfide but not sulfite as a sulfur source. The mutant was found to be RC(rel) with respect to both methionine and cysteine. During cysteine starvation, transfer ribonucleic acid (tRNA) deficient in 4-thiouracil was produced, and in vivo studies indicate that this tRNA can accept sulfur groups to a greater extent than normal tRNA. Further, there were differences both in the rate and extent of amino acid acceptance between normal and sulfur-deficient tRNA. This suggests that thionucleotides are involved in at least one of the biological functions of the tRNA molecule.     

Population structure of Sclerotinia sclerotiorum in an Australian canola field at flowering and stem-infection stages of the disease cycle.

Populations of the ascomycete pathogen Sclerotinia sclerotiorum sampled from a canola field were analysed using microsatellite markers. Fifty isolates were collected from ascospore-infested canola petals and, later in the season, another 55 isolates were obtained from stem lesions; these isolates were used to compare inoculum and disease-causing populations. Fifty-five unique haplotypes were identified, with gene diversity ranging from 0.40 to 0.71. Genotypic diversity was higher in the inoculum population than it had been in the previous year, but analysis of molecular variance (AMOVA) showed that less than 10% of the variation was attributable to differences between the 2 years. Genotypic disequilibrium measures were consistent with the occurrence of both clonal reproduction and out-crossing. There was no significant population subdivision between the ascospore and stem-lesion populations, as measured with fixation indices (R(ST) = 0.015, p = 0.90) and AMOVA, suggesting that there are no genetically defined subgroups of isolates more likely to proceed from petal colonization to cause stem infection. This might be because S. sclerotiorum possesses wide-ranging pathogenicity mechanisms that account for the lack of host specificity observed to date.     

Expression of paternal glucose phosphate isomerase-1 (Gpi-1) in preimplantation stages of mouse embryos

Electrophoretic variants of glucose phosphate isomerase have been used to study the time of paternal gene activation during early embryogenesis of the mouse. Hybrid embryos obtained from matings of GPI-1A ♀ X GPI-1B ♂ were examined electrophoretically, and assayed for GPI activity during preimplantation stages. The heteropolymeric GPI-1AB band was detected in late blastocysts and all three bands of the hybrid pattern were discernible in samples of expanded blastocysts, day 6. These findings indicate that the Gpi-1 paternal locus is expressed by day 5. Activity levels of GPI were comparable to values reported for G6PD. The activity of GPI was constant for days 1, 2, and 3; however, a marked decrease in activity occurred by day 4. A slight decrease in activity was observed in embryos from days 5 and 6. Our results demonstrate the value of using electrophoretic variants to pinpoint synthesis of new enzyme which may not be reflected in changes in levels of activity.