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PubMed1988

The role of sterility genes (ste and aff) in the initiation of sexual development in Schizosaccharomyces pombe.

Haploid homothallic strains of Schizosaccharomyces pombe with mutations in any of nine "sterility genes" (ste) do not mate with wild-type fertile strains. Those defective in genes ste1 to ste4 and ste7 to ste9 are also deficient in meiosis and sporulation. I found that the ste1, ste3 and ste8 genes act very early in the sexual development, presumably before the pat1-controlled conjugation-specific event. ste5 and ste6 exert their function downstream of pat1 in the initiation of conjugation and do not play any role in the meiotic pathway. ste2, ste4, ste7 and ste9 are involved in both sexual pathways: they seem to act downstream of pat1 in conjugation but upstream of pat1 in the initiation of meiosis. A new gene, aff1, whose defective allele suppresses the pat1-114-provoked haploid sporulation and arrest of vegetative growth is also described. It is supposed that the aff1+ gene product participates in a cascade of regulatory events, as a factor antagonistic to pat1.

Alleles↗
PubMed1986

Phagocytic specificity during sexual development in Dictyostelium discoideum.

During the sexual cycle of Dictyostelium discoideum, zygote giant cells develop and serve as foci for further development by chemoattracting and cannibalizing hundreds of local amoebae. Previous work has shown that the phagocytic process bears similarities to and differences from asexual endocytosis. In the present study, sexual phagocytosis in D. discoideum was found to be species and developmental stage specific. It was inhibited selectively by glucose and concanavalin A. Although a partial, inhibitory effect of mannose on phagocytosis was not statistically significant, alpha-methylmannosamine, like alpha-methyl-glucose, significantly restored the phagocytic competence of giant cells treated with concanavalin A. Other sugars (N-acetyl-glucosamine, N-acetylgalactosamine, and galactose) and lectins (wheat germ agglutinin, Ulex europus type I, and Ricinis communis agglutinin type I) had no significant effect on sexual phagocytosis. Together these data indicate that a glucose-type receptor is involved in selective uptake of D. discoideum amoebae by giant cells.

Carbohydrates↗
PubMed1992

Effects of neonatal exposure to the antiprogestin mifepristone, RU 486, on the sexual development of the rat.

RU 38486 (RU 486, mifepristone) is a potent progesterone receptor antagonist that has been used in humans in the pharmacologic induction of abortion. The effects of exposure to RU 486 during the neonatal period of the rat has not been previously reported. We examined the consequences of such exposure in the context of sexual development. Long-Evans rat pups were subcutaneously injected with either 100 micrograms RU 486, 300 micrograms RU 486, 500 micrograms progesterone (P), or 50 micrograms testosterone propionate (TP) in 0.05 ml sesame oil, or oil vehicle alone within 8 hours of birth, and 24 and 48 hours later. Treatment with either dose of RU 486 significantly advanced the onset of vaginal opening in females and attenuated defeminization of the lordosis response measured in males castrated as adults. As expected, TP-treated subjects were masculinized and defeminized, with females displaying fused vaginas and neither males nor females demonstrating lordosis behavior. Treatment with P caused no significant alterations in either the timing of vaginal opening or sexual behavior. These results indicate that RU 486 has clear developmental effects in the rat. Since this may well be a result of progesterone receptor blockade, further research is needed to clarify the processes involved.

Animals↗
PubMed1975

Altered sexual development in male rats after oestrogen administration during the neonatal period.

Male rats given 250 mug oestradiol benzoate by subcutaneous injection on Day 4 of postnatal life showed a marked delay in the onset of the pubertal increase in the weight of the testes and seminal vesicles and in spermatogenesis but not a complete failure of sexual development. The increase in plasma testosterone concentration at puberty was also delayed in oestrogen-treated males but the eventual increase in seminal vesicle weight was closely related in time to the delayed increase in plasma testosterone concentration. Both plasma LH and FSH concentrations were reduced for about 10 days after oestrogen administration as compared to control values. After 22 days of age, plasma LH concentration did not differ significantly from the control values. The plasma FSH concentration of the oestrogen-treated males showed a delayed rise to values equal to or higher than those of controls of the same age. The delayed rise in plasma FSH concentration in the oestrogen treated males preceded the delayed rise in plasma testosterone in these animals. The decrease in plasma FSH concentration from the high prepubertal values to the lower values in adults occurred at different ages in the control and in oestrogen-treated rats but in both groups the decrease occurred as plasma testosterone levels were increasing and the first wave of spermatogenesis was reaching completion. The increase in plasma FSH concentration after castration was reduced in oestrogen-treated males during the period throughout which FSH levels in the intact animals were subnormal but the levels in oestrogen-treated males castrated after the delayed rise in FSH had occurred did not differ from control values. It is suggested that the delayed sexual maturation of male rats treated with high doses of oestrogen in the neonatal period is related principally to abnormalities in the secretion of FSH.

Animals↗
PubMed1987

Deleterious effects of adrenocorticotrophic hormone administration during late pregnancy upon offspring somatic, neurological, and sexual development in mice.

The influence of administration of adrenocorticotrophic hormone (ACTH) during days 12-17 of pregnancy upon somatic, neurological, and neuromuscular development of offspring in mice was studied. The effects upon the onset of puberty in female offspring was also examined. Litters from mice given the higher of two doses of ACTH (1 IU/day or 8 IU/day) showed lower body weights at birth and weaning than controls. This treatment also increased pre- and postnatal mortality rates, although not significantly. Litters from mice treated with either dose of ACTH showed retarded development of the forelimb and hindlimb grasp reflexes, the body righting reflex, the auditory startle response, and eye opening. Although ear opening was delayed in litters from ACTH-treated mice, results did not achieve statistical significance. Study of female offspring housed in small groups revealed that one indicator of puberty, vaginal opening, was delayed in female offspring of ACTH-treated mice. Experiments were conducted to identify factors mediating this syndrome: ACTH did not depress maternal food intake or alter the length of pregnancy, therefore fetal undernutrition or premature birth can be excluded as mediating factors. All litters were fostered to untreated mice to control for postnatal factors influencing development. As ACTH cannot cross the placenta, the syndrome is likely to result from in utero exposure to abnormally high concentrations of glucocorticosteroids of maternal origin. It is concluded that such alterations to the fetal environment can exert a deleterious influence upon somatic, neurological, and sexual development, and that hormones of the maternal pituitary-adrenocortical axis may naturally act to regulate general development of the fetus.

Adrenocorticotropic Hormone↗
PubMed1984

5 Alpha- and 5 beta-reductases for 4-ene-3-ketosteroids and 17 beta-ol-dehydrogenase in epididymis and testis of golden hamster during sexual development.

Homogenates of the epididymis, testis and seminal vesicle from 15, 25, 35 and 60-day old golden hamsters were incubated with [3H]4-androstene-3,17-dione and NADPH and enzyme activity was estimated. In the testis, activities of 5 alpha- and 5 beta-reductases were the highest (32 +/- 4 and 68 +/- 13 (SD) nmol/100 mg protein/h, respectively) at 25 days of age, moderately high at 35 days and very low (1-3 and 5-6, nmol/100 mg protein/h, respectively) at 15 and 60 days. In the epididymis, 5 alpha-reductase activities increased with age during sexual development by up to 50-fold and reached the maximum value (40 +/- 11 nmol/100 mg protein/h) at 60 days. The 5 alpha-reductase activities in the seminal vesicle were found to be relatively low (0.5-1 nmol/100 mg protein/h), compared with those in the epididymis and testis. Activities of 5 beta-reductase in the epididymis and seminal vesicle were very low (0.1-0.5 nmol/100 mg protein/h) at all ages. These results indicate the existence of a marked, but transient, increase in 5 alpha- and 5 beta-reductase activities during immature period in the testis of golden hamster. In the epididymis, however, 5 alpha-reductase activity increases with age during sexual maturation, while 5 beta-reductase activity is almost undetectable at all ages.

17-Hydroxysteroid Dehydrogenases↗
PubMed1991

The tubB alpha-tubulin gene is essential for sexual development in Aspergillus nidulans.

The filamentous fungus Aspergillus nidulans has two genes encoding alpha-tubulin, tubA and tubB. Mutational analysis of tubA has demonstrated that the tubA gene is essential for mitosis and nuclear migration. In this study we have deleted the tubB gene by replacing it with a selectable marker and have named this new allele tubB delta. The results demonstrate that the tubB gene is not required for vegetative growth or asexual reproduction, nor is it required for the initiation or early stages of sexual differentiation. Deletion of tubB, however, completely prevents ascosporogenesis, because tubB delta strains produce no sexual spores when self-crossed. These strains produce viable ascospores when outcrossed to tubB+ strains, indicating that the tubB delta mutation is recessive. We have studied the cytology of sexual development in wild-type strains and in the tubB mutant and have observed that tubB delta. strains develop normally to the stage of ascus formation. However, only a single nuclear mass is observed in the tubB delta ascus, indicating that either the two zygotic haploid nuclei are blocked in karyogamy or that karyogamy occurs but the resulting diploid nucleus is subsequently blocked in meiosis I.

Aspergillus nidulans↗
PubMed1981

Dominant spore color mutants of Aspergillus nidulans defective in germination and sexual development.

The ascomycete Aspergillus nidulans produces green conidia (asexual spores). Recessive mutants which produce yellow conidia have been previously isolated from haploid strains and have been shown to be deficient in laccase (diphenol oxidase), an enzyme that requires copper for activity. Using a diploid parent strain, we isolated dominant yellow conidial mutants which, in the haploid state, produced even less laccase activity than a recessive mutant. Three isolates of such mutants behaved similarly and define a single complementation group (yB) on chromosome VIII distinct from the yA locus on chromosome I defined by recessive mutants. Unlike yA mutants, whose only discernable phenotype is their conidial color, yB mutants are pleiotropic: conidial germination was delayed relative to the wild type, and sexual development was blocked at an early stage. The three phenotypes of yB mutants were expressed on yeast extract-glucose medium containing 1.6 microM of added copper. When copper was added to above 5 microM, all three phenotypes were remediated, and near wild-type levels of laccase were produced. We conclude that yB mutants have a reduced availability of copper. The dominance of yB mutants could result, for example, from an alteration in transport or storage of copper. Using an immunological assay, we detected no laccase antigenic cross-reacting material in yB mutants grown on medium of low copper content. We conclude that either the synthesis or the stability of laccase is copper dependent.

Aspergillus nidulans↗
PubMed1982

Concentrations of luteinizing hormone and progesterone in plasma during sexual development of the Khaki Campbell duck.

Concentrations of LH and progesterone were measured in the plasma of ducks which were, from 3 weeks of age, raised on either a constant photoperiod of 16 h light: 8 h darkness or a lighting schedule which stimulated natural changes in daylength. In ducks raised on a constant photoperiod of 16 h light: 8 h darkness the plasma concentration of LH increased steeply between 7 and 3.5 weeks before the onset of lay. Concentrations of LH then declined, gradually at first, but them rapidly during the 7 days before the first oviposition in association with a pronounced increase in the plasma concentration of progesterone. During the 18 days before the first egg was laid there was a significant (P less than 0.01) negative correlation between the plasma concentrations of LH and progesterone. The patterns of LH release during sexual development of ducks raised on a schedule which stimulated natural changes in daylength were variable but could be categorized according to the daylength at which each duck came into lay. In ducks coming into lay soon after the winter solstice when daylength was short (8.0-8.5 h light/day) there was a pronounced 15-fold prepubertal increase in the plasma concentration of LH although in some ducks high LH levels were not maintained until 3-4 weeks before the first oviposition and were not always followed by a rise in the plasma concentration of progesterone. In contrast, in ducks coming into lay when daylength had increased to 11.0-11.5 h light/day there were only minor fluctuations in the plasma concentration of LH until a small two- to threefold increase in LH was observed during the 2 weeks before the first oviposition.

Animals↗
PubMed1992

[A body of one's own. Sexual development and physical female development in the mother-child relationship].

Prevalent psychoanalytic opinion has it that (sexually) femaleness is marked by a severe deficiency. Accordingly it is widely held that the acknowledgement of female sexuality is primarily a matter for fathers rather than mothers. The author takes a different stance, insisting on the opportunities inherent in the mother-daughter relationship to the extent that it both permits and encourages pleasurable self-examination and acceptance of the body on the part of the growing girl. In the therapeutic connection, the author calls for a form of remedial socialisation to fill the specific lacunae that have developed around female sexuality.

Body Image↗
PubMed1987

Lectin binding and inhibition studies reveal the importance of D-glucose, D-mannose and N-acetylglucosamine during early sexual development of Dictyostelium discoideum.

Fluorescein-conjugated and non-conjugated lectins were used to determine which surface sugars are involved in the early events of sexual (macrocyst) development in Dictyostelium discoideum. Only zygote giant cells showed unique binding of FITC-WGA and FITC-PNA while all cell types (amoebae, gametes, binucleates, giant cells) showed identical patterns of FITC-Con A, -Gorse and -RCA II binding. In spite of its non-selective labelling of all cell types, Con A inhibited macrocyst formation. The temporal addition of Con A with and without specific hapten sugars indicates the importance of both D-mannose and D-glucose in phagocytosis and, possibly, cell fusion. WGA also inhibited macrocyst formation. Varying the time of addition of the lectin plus/minus its primary hapten sugar implicates N-acetylglucosamine as being important in cell fusion. Neither Gorse, RCA II nor PNA had any detectable inhibitory effects on macrocyst development leaving the appearance of increased PNA receptors at the giant cell surface as an enigma.

Acetylglucosamine↗
PubMed1990

Cellular events during sexual development from amoeba to plasmodium in the slime mould Physarum polycephalum.

Time-lapse cinematography and immunofluorescence microscopy were used to study cellular events during amoebal fusions and sexual plasmodium development in Physarum polycephalum. Amoebal fusions occurred frequently in mixtures of strains heteroallelic or homoallelic for the mating-type locus matA, but plasmodia developed only in the matA-heteroallelic cultures. These observations confirmed that matA controls development of fusion cells rather than cell fusion. Analysis of cell pedigrees showed that, in both types of culture, amoebae fused at any stage of the cell cycle except mitosis. In matA-heteroallelic fusion cells, nuclear fusion occurred in interphase about 2 h after cell fusion; interphase nuclear fusion did not occur in matA-homoallelic fusion cells. The diploid zygote, formed by nuclear fusion in matA-heteroallelic fusion cells, entered an extended period of cell growth which ended in the formation of a binucleate plasmodium by mitosis without cytokinesis. In contrast, no extension to the cell cycle was observed in matA-homoallelic fusion cells and mitosis was always accompanied by cytokinesis. In matA-homoallelic cultures, many of the binucleate fusion cells split apart without mitosis, regenerating pairs of uninucleate amoebae; in the remaining fusion cells, the nuclei entered mitosis synchronously and spindle fusion sometimes occurred, giving rise to a variety of products. Immunofluorescence microscopy showed that matA-heteroallelic fusion cells possessed two amoebal microtubule organizing centres, and that most zygotes possessed only one; amoebal microtubule organization was lost gradually over several cell cycles. In matA-homoallelic cultures, all the cells retained amoebal microtubule organization.

Animals↗
PubMed1985

Dynamics of physiological changes in bovine myofibers during growth and sexual development.

Semitendinosus (ST) muscle samples were excised from 8 intact and 8 castrate male animals (Bos taurus) when they reached age end-points of 8, 12, 16, and 20 months. All three principal myofiber phenotypes (IC, IIA, IIB) increased in size with increasing age, with the IIA (fast-white) fibers usually larger than the other two types. Only at 16 and 20 months were the type II myofibers from intact males consistently larger than that from castrates. The amount of IIA fibers always exceeded that of the other two phenotypes at every age. Myofiber characteristics were more highly correlated with animal age than with either total body weight or total muscle mass. An ontogenetic scheme is proposed to illustrate the dynamic interrelationships of the three ST myofiber phenotypes.

Age Factors↗