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PubMed2000

Genetic, behavioral and environmental determinants of male longevity in Caenorhabditis elegans.

Males of the nematode Caenorhabditis elegans are shorter lived than hermaphrodites when maintained in single-sex groups. We observed that groups of young males form clumps and that solitary males live longer, indicating that male-male interactions reduce life span. By contrast, grouped or isolated hermaphrodites exhibited the same longevity. In one wild isolate of C. elegans, AB2, there was evidence of copulation between males. Nine uncoordinated (unc) mutations were used to block clumping behavior. These mutations had little effect on hermaphrodite life span in most cases, yet many increased male longevity even beyond that of solitary wild-type males. In one case, the neuronal function mutant unc-64(e246), hermaphrodite life span was also increased by up to 60%. The longevity of unc-4(e120), unc-13(e51), and unc-32(e189) males exceeded that of hermaphrodites by 70-120%. This difference appears to reflect a difference in sex-specific life span potential revealed in the absence of male behavior that is detrimental to survival. The greater longevity of males appears not to be affected by daf-2, but is influenced by daf-16. In the absence of male-male interactions, median (but not maximum) male life span was variable. This variability was reduced when dead bacteria were used as food. Maintenance on dead bacteria extended both male and hermaphrodite longevity.

Animals↗
PubMed2000

courtless, the Drosophila UBC7 homolog, is involved in male courtship behavior and spermatogenesis.

The courtless (col) mutation disrupts early steps of courtship behavior in Drosophila males, as well as the development of their sperm. Most of the homozygous col/col males (78%) do not court at all. Only 5% perform the entire ritual and copulate, yet these matings produce no progeny. The col gene maps to polytene chromosome band 47D. It encodes two proteins that differ in their carboxy termini and are the Drosophila homologs of the yeast ubiquitin-conjugating enzyme UBC7. The col mutation is caused by an insertion of a P element into the 3' UTR of the gene, which probably disrupts translational regulatory elements. As a consequence, the homozygous mutants exhibit a six- to sevenfold increase in the level of the COL protein. The col product is essential, and deletions that remove the col gene are lethal. During embryonic development col is expressed primarily in the CNS. Our results implicate the ubiquitin-mediated system in the development and function of the nervous system and in meiosis during spermatogenesis.

Alleles↗
PubMed1980

Caenorhabditis elegans fertilization-defective mutants with abnormal sperm.

Seven new fertilization-defective mutants of C. elegans have been isolated and characterized; six are temperature sensitive, one is absolute and all are autosomal recessive. One mutation is in a previously described gene, while the other six define six new fer genes that appear to code for sperm-specific functions necessary for normal fertilization. In all fer mutants, both males and hermaphrodites accumulate sperm in near normal numbers. In hermaphrodites, mutant sperm contact the oocytes, but fail to fertilize them. Instead, the sperm are swept into the uterus by the passing oocytes and are expelled when oocytes are laid. Males of two fer mutants do not transfer sperm during copulation, but the other mutant males transfer sperm that fail to move to the spermatheca. Spermatozoa from fer-1 and fer-4 mutants are motility-defective in vitro as well as in vivo, and their pseudopods have an altered morphology. The period of development during which mutant hermaphrodites are temperature sensitive for fertility overlaps the time of sperm development. Some mutants are temperature sensitive throughout the entire period, and others are temperature sensitive during or just prior to spermiogenesis. In fer-4/+ and fer-7/+ males, the fertility of the mutation-bearing sperm is diminished, reducing the transmission ratio. This implies some post-meiotic expression of these genes.--This set of mutants provides a variety of functional and structural alterations in nematode sperm that should help identify and analyze gene products involved in sperm morphogenesis and motility.

Animals↗
PubMed1982

Sociosexual and hormonal changes in aging female bonnet macaques.

A comparison of younger mature and older perimenopausal female bonnet macaques showed differences in sexual interaction with males. Older females evoked significantly fewer copulations than did younger females. Although older females were cycling regularly, the midcycle (estrus) peaking of sexual interaction and levels of plasma estradiol were less pronounced in older than in younger females. Younger females were mounted more during estrus than during the luteal phase of their cycles, and the frequency of ejaculations and duration of intromissions were significantly greater during estrus. These cycle-phase differences were not observed with older females. The results suggest that aging in the female macaque is associated with reduction in sexual attractiveness to males. The possibility that changes in female proceptivity and receptivity contribute to this effect remains to be investigated.

Aging↗
PubMed1999

A retroviral gene trap insertion into the histone 3.3A gene causes partial neonatal lethality, stunted growth, neuromuscular deficits and male sub-fertility in transgenic mice.

Spermatogenesis is a complex developmental pro-cess involving cell division and differentiation. Approximately half of all sterile males have defects in spermatogenesis or sperm function. An insight into the molecular control points regulating this process might help in treating male infertility. Gene trapping in embryonic stem cells and the generation of transgenic mice represents one route to identify genes expressed during spermatogenesis. The trapped gene is tagged with a lacZ reporter gene so that the expression pattern of the gene can be visualized by staining for beta-galactosidase activity. We have screened transgenic mouse lines for expression of trapped genes in the gonads. One such trap event was shown to be in the replacement histone 3.3A gene ( H3.3A ). This gene was expressed ubiquitously during embryonic development until 13.5 days post-coitum and in the adult heart, kidney, brain, testes and ovaries. This mutation resulted in postnatal death of 50% of homozygous mutants. Surviving mutants displayed reduced growth rates when competing with wild-type siblings for food. Mutant mice also had a neuro-muscular deficit and males displayed reduced copulatory activity. When copulations did occur, these resulted in very few pregnancies, suggesting that mutations in the H3.3A gene may contribute to some cases of impaired fertility in man.

Animals↗
PubMed2006

Metoclopramide-induced hyperprolactinaemia caused marked decline in pinopodes and pregnancy rates in mice.

BACKGROUND: The impact of hyperprolactinaemia on endometrial function, along with embryo implantation, has been the subject of discussion. This article examines whether experimental hyperprolactinaemia can affect mouse ovarian function, endometrial pinopodes and embryo implantation. METHODS: For pinopode analysis, 60 female mice were randomly divided into two groups: control (vehicle) and experimental [metoclopramide (MCP) 200 microg per day]. Injections were given subcutaneously for 50 days, and then, normally cycling females were housed with male mice for copulation during proestrus. The animals were killed on the fifth day following coitus when the antimesometrium portions of the uterine horns were removed for endometrial analysis. Blood was collected for prolactin (PRL) determination. In the second experiment, 60 female mice were used to evaluate the ovarian function by measuring estrogen and progesterone levels and counting luteal bodies and oocytes in the oviduct and uterus during estrus. RESULTS: The highest pregnancy rates and the largest population of pinopodes were both found in the vehicle group (P<0.01). Estrogen and progesterone levels in MCP-treated mice were lower than those in control mice (P<0.05). Also, the number of implantations was significantly lower in the MCP-treated group compared with the vehicle group after embryo transfer (P<0.001). CONCLUSION: PRL seems to have suppressive effects on ovarian function and the number of pinopodes; conceivably, hyperprolactinaemia has a negative effect on mouse embryo implantation.

Animals↗
PubMed1990

Morphogenetic effects of hydroprene on genitalia of the oriental cockroach (Dictyoptera: Blattidae).

Hydroprene had a considerable effect on the morphogenesis of external genitalia of the oriental cockroach, Blatta orientalis L. Exposure of nymphs to hydroprene resulted in abnormal adultoids with structural and positional distortions, and reduced or absent cuticular sclerotizations of the external genitalia. Late nymphal instars were significantly more sensitive to hydroprene than were early instars. In males, the epithelial cells of wings, serrata of the right phallomere, titillator and other lobes of the left phallomere were sensitive to hydroprene. The left phallomere was often prolapsed, distorted, and reduced in sclerotization. The right phallomere, particularly the serrata, was extremely malformed. In severe cases, phallomeres were entirely distorted or fused to each other. In females, the overall structure of the ovipositor appeared flaccid, less sclerotized, and misshapen. The first and second pairs of valvulae were often misshapen and reduced in sclerotization and length, or even fused with the third valvulae. This study provides morphological evidence that B. orientalis with malformed genitalia after treatment with hydroprene would be unsuccessful in copulation and fertilization. A high correlation between wrinkled wings and malformed male genitalia can be an important criterion to evaluate the effects of hydroprene on this species.

Animals↗
PubMed2005

Strong reproductive skew among males in the multiply mated swordtail Xiphophorus multilineatus (Teleostei).

Male swordtails in the genus Xiphophorus display a conspicuous ventral elongation of the caudal fin, the sword, which arose through sexual selection due to female preference. Females mate regularly and are able to store sperm for at least 6 months. If multiple mating is frequent, this would raise the intriguing question about the role of female choice and male-male competition in shaping the mating system of these fishes. Size-dependent alternate mating strategies occur in Xiphophorus; one such strategy is courtship with a sigmoid display by large dominant males, while the other is gonopodial thrusting, in which small subordinate males sneak copulations. Using microsatellite markers, we observed a frequency of multiple paternity in wild-caught Xiphophorus multilineatus in 28% of families analyzed, but the actual frequency of multiple mating suggested by the correction factor PrDM was 33%. The number of fathers contributing genetically to the brood ranged from one to three. Compared to other species in the family Poeciliidae, both frequency and degree of multiple paternity were low. Paternity was found to be highly skewed, with one male on average contributing more than 70% to the offspring. Hence in this Xiphophorus mating system, typically one male dominates and sneaker males do not appear to be particularly effective. Postcopulatory mechanisms, however, such as sperm competition, are also indicated by our data, using sex-linked phenotypes among the offspring.

Animals↗
PubMed1992

Laboratory observations on mating and leklike aggregations in Lutzomyia longipalpis (Diptera: Psychodidae).

The mating behavior of the sand fly, Lutzomyia longipalpis, was studied under laboratory conditions. Male sand flies landed on the bodies of anesthetized mice, where they exhibited leklike displays such as wing fanning, parading, and aggression. Lek behavior was more frequent in older males, and dominance hierarchies were established. Male sand flies at leks copulated more frequently than male sand flies at other locations in the cage. Females mated by older males produced more eggs than did females mated by younger males; however, there was no difference in the number of larvae produced.

Animals↗
PubMed2005

Entropy and GC Content in the beta-esterase gene cluster of the Drosophila melanogaster subgroup.

We perform spectral entropy and GC content analyses in the beta-esterase gene cluster, including the Est-6 gene and the psiEst-6 putative pseudogene, in seven species of the Drosophila melanogaster species subgroup. psiEst-6 combines features of functional and nonfunctional genes. The spectral entropies show distinctly lower structural ordering for psiEst-6 than for Est-6 in all species studied. Our observations agree with previous results for D. melanogaster and provide additional support to our hypothesis that after the duplication event Est-6 retained the esterase-coding function and its role during copulation, while psiEst-6 lost that function but now operates in conjunction with Est-6 as an intergene. Entropy accumulation is not a completely random process for either gene. Structural entropy is nucleotide dependent. The relative normalized deviations for structural entropy are higher for G than for C nucleotides. The entropy values are similar for Est-6 and psiEst-6 in the case of A and T but are lower for Est-6 in the case of G and C. The GC content in synonymous positions is uniformly higher in Est-6 than in psiEst-6, which agrees with the reduced GC content generally observed in pseudogenes and nonfunctional sequences. The observed differences in entropy and GC content reflect an evolutionary shift associated with the process of pseudogenization and subsequent functional divergence of psiEst-6 and Est-6 after the duplication event.

Animals↗
PubMed1989

Co-administration of ascorbic acid with cyclophosphamide (CPA) to pregnant mice inhibits the clastogenic activity of CPA in preimplantation murine blastocysts.

Cyclophosphamide (CPA) administered at a dose of 15 mg/kg body weight to pregnant inbred CBA/CaH mice 60 h after copulation significantly elevated the incidence of structural chromosomal aberrations and sister-chromatid exchanges in 96 h blastocysts. When ascorbic acid (800 mg/kg body weight) was co-administered with CPA (15 mg/kg) using different injection sites, the incidence of structural chromosomal aberrations and the number of aberrant metaphases were significantly lower as compared to the CPA-exposed embryos, but still significantly higher than untreated controls. Sister-chromatid exchanges were not significantly different in embryos exposed to CPA only when compared to those exposed to CPA and ascorbic acid. In terms of the developmental potential of embryos, pregnant mice injected with both CPA and ascorbic acid had significantly fewer resorptions per mouse, and a significantly higher number of viable fetuses retrieved on the 18th day of gestation when compared to mice injected with CPA alone. The data in this study demonstrate that the co-administration of ascorbic acid with CPA to pregnant mice ameliorates the CPA-induced clastogenicity and improves the developmental potential of these embryos. This study suggests that some of the CPA-induced genotoxicity is due to the generation of reactive oxygen molecules, but further research is necessary before this can be firmly concluded.

Animals↗
PubMed1996

Effect of platelet activating factor on embryonic development and implantation in the mouse.

Platelet activating factor (PAF) was administered to female mice in order to investigate its effect on ovulation rate and on oocyte quality including their in-vitro embryonic development, implantation and uterine receptivity. In experiment 1, 4-week-old female mice were assigned to receive PAF or phosphate buffered saline for 4 consecutive days. On the second day of this treatment, pregnant mares' serum gonadotrophin was administered and human chorionic gonadotrophin (HCG) 48 h later, after which copulation occurred. Oocytes were collected on the following day and evaluated. The mean number of oocytes and zygotes (two pronuclear stage embryos) recovered from the PAF-treated group was not different from the control group (31 versus 27), but the proportion of zygotes was higher in PAF-treated group than in controls (83 versus 68%, P < 0.05, PAF versus controls). Although the rate of in-vitro first cleavage was not different in the two groups (82 versus 69% respectively), hatching was higher in the PAF-treated group than control mice (99 versus 83%, P < 0.01). In experiment 2, the in-vitro developed blastocysts from experiment 1 were transferred into the uterus of day 3 pseudopregnant PAF-treated or control recipients. Three different combinations of intrauterine transfer were performed; PAF embryo to control recipient (PAF-->C: n = 19), control embryo to PAF recipient (C-->PAF: n = 19), and control embryo to control recipient (C-->C: n = 22). Implantation and abortion were assessed on day 19 posttransfer. The implantation rate of C-->PAF (23.7%) was lower than C-->C (31.1%, P < 0.05), but was not different from PAF-->C (31.2%). Further, C-->PAF showed a higher abortion rate per embryo (29.6%) than PAF-->C (12.7%, P < 0.05), but was not different from C-->C (24.4%). In the present study, PAF administration enables females to produce oocytes with a higher potential for fertilization, in-vitro development and implantation, but has a detrimental effect on uterine receptivity to embryos.

Animals↗
PubMedDate not supplied

A red stripe mutant and its relationship in an allelic series in Anopheles quadrimaculatus.

A red stripe phenotype from a natural population of Anopheles quadrimaculatus (Say) was introduced into a laboratory colony by induced copulation. Genetic crosses made with the red stripe (strd) mutant showed it to be a member of an allelic series with stripe (st+) and nonstripe (st). The strd character is condominant with st+, and st is recessive to both strd and st+.

Alleles↗
PubMed2003

Potential relationships between physical traits and male broiler breeder fertility.

Genetic selection in primary broiler breeders may modify skeletal structure, possibly impeding semen transfer, and could alter the size and degree of fluctuating asymmetry (FA) of bilateral traits associated with fertility. Hence, we hypothesized specific morphometric traits could predict differential fertility. Sixty primary broiler breeder males from Strains A and B (n = 30/strain) were individually housed with an average of 10 females per male. Male fertility and sperm penetration (SP) through the perivitelline layer were estimated on fresh eggs. At 50 wk, BW, keel length (KL), posterior pelvic width and length (PPW, PPL), dorsal pelvic width and length (DPW, DPL), tarsometatarsal length and width (TL, TW), comb length and width (CL, CW), and wattle length, width, and area (WL, WW, WA) were measured. Results indicated that Strain A had smaller BW, KL, WL, WW, WA, CL, CW, PPL, DPL, and DPW. A higher degree of FA was found in Strain A TL and WL (P < 0.05), yet DPW FA was greater for Strain B (P < 0.001). In addition, DPW FA negatively correlated with Strain B fertility (r = -0.369; P < 0.01); however, other FA measurements did not correlate with estimated fertility or SP. Strain A WL correlated with SP (r = 0.383; P < 0.01) and fertility (r = 0.346; P < 0.01). Results indicate DPW alteration may impact semen transfer upon copulation, as Strain A fertility negatively correlated with DPW (r = -0.298; P < 0.05). This research provides evidence that morphometric traits might be useful to predict fertility in broiler breeders.

Animals↗
PubMed1999

Reproductive toxicity studies in rats with rimexolone, a corticoid ophthalmic suspension.

Rimexolone is a potent anti-inflammatory corticosteroid with a lower potential for elevating intraocular pressure, relative to other ophthalmic steroids, and is indicated for postsurgical inflammation and uveitis. Fertility and peri/postnatal toxicities were evaluated at oral gavage doses of 50, 150 or 500 mg/kg, and developmental toxicity at 100, 500, or 1000 mg/kg. In the fertility study, male rats were treated daily beginning 4 weeks prior to mating and females were treated daily beginning 2 weeks prior to mating, and through gestation day 6. Females were necropsied on gestation day 15 and males were necropsied after 10 weeks of exposure. In males, dose-related reductions in mean body weights, body weight gains, and food consumption occurred in all groups. In the 500 mg/kg females, mean body weights were reduced during gestation, and there was an increase in early resorptions and concomitant decrease in viable fetuses at this level. There were no effects on copulation or fertility indices, or on the number of corpora lutea and implantation sites. The no-observed-effect level (NOEL) for fertility and reproductive effects was 150 mg/kg. In the developmental toxicity study, female rats were treated daily from gestation days 6 through 17, necropsied on gestation day 20 and fetuses were evaluated. Maternal toxicity occurred at 500 and 1000 mg/kg as indicated by reduced maternal body weights and body weight gains. However, there was no indication of a developmental effect on fetuses due to rimexolone. The NOEL was 1000 mg/kg for the developing fetuses. In the peri/postnatal toxicity study, female rats were treated daily from gestation day 6 through lactation day 20 and necropsied. F1 developmental and behavioral parameters were evaluated. Selected F1 animals were mated at 12 weeks, allowed to deliver, and necropsied on lactation day 21. At 500 mg/kg, F0 maternal body weights were reduced during gestation and lactation, and F1 pup weights were reduced during lactation and the growth phase. There were no effects on the F1 fertility or reproductive capabilities, or on F2 developmental parameters. The NOEL for the F0 females and F1 offspring was 150 mg/kg. Together, these studies indicate that, unlike some corticosteroids, rimexolone does not produce developmental or reproductive toxicity in rats.

Administration, Topical↗
PubMed2003

In utero through lactational exposure to ethinyl estradiol induces cleft phallus and delayed ovarian dysfunction in the offspring.

Most of the attention currently focused on endocrine-active chemicals is directed to their effects on the development of offspring exposed to them in utero or during the neonatal period. Pregnant Crj:CD(SD)IGS rats were given ethinyl estradiol (EE) orally in doses of 0.5-50 microg/kg/day from gestational day 7 to postnatal day 18, and their offspring were examined for its effects. Our previous study according to a similar protocol demonstrated the occurrence of cleft phallus in the female offspring exposed to 50 microg/kg of EE in utero and during the lactation period. The present study was designed to assess (1) the reproducibility of the induction of cleft phallus, (2) the fertility of female rats with cleft phallus, and (3) whether any delayed effects, possibly delayed anovulation, were induced. At 50 microg/kg cleft phallus was observed in almost all of the female offspring, and slight retardation of body weight gain was detected in both sexes. At 15-17 weeks of age the animals with cleft phallus could copulate and had fertility comparable to the control group. At 6 months of age, on the other hand, 6/8 of the female offspring at 50 microg/kg exhibited abnormal cyclicity, including persistent estrus, and histological examination revealed follicular cysts and absence of corpora lutea in the ovaries of the rats with persistent estrus. These findings are consistent with delayed anovulation syndrome. The results suggest that observation of cyclicity at 6 months old is able to detect possible delayed ovarian dysfunction induced by perinatal exposure to chemicals.

Abnormalities, Drug-Induced↗
PubMed2004

Male fertility in natural populations of red deer is determined by sperm velocity and the proportion of normal spermatozoa.

Male reproductive success is determined by the ability of males to gain sexual access to females and by their ability to fertilize ova. Among polygynous mammals, males differ markedly in their reproductive success, and a great deal of effort has been made to understand how selective forces have shaped traits that enhance male competitiveness both before and after copulation (i.e., sperm competition). However, the possibility that males also may differ in their fertility has been ignored under the assumption that male infertility is rare in natural populations because selection against it is likely to be strong. In the present study, we examined which semen traits correlate with male fertility in natural populations of Iberian red deer (Cervus elaphus hispanicus). We found no trade-offs between semen traits. Our analyses revealed strong associations between sperm production and sperm swimming velocity, sperm motility and proportion of morphologically normal spermatozoa, and sperm viability and acrosome integrity. These last two variables had the lowest coefficients of variation, suggesting that these traits have stabilized at high values and are unlikely to be related to fitness. In a fertility trial, our results show a large degree of variation in male fertility, and differences in fertility were determined mainly by sperm swimming velocity and by the proportion of morphologically normal sperm. We conclude that male fertility varies substantially in natural populations of Iberian red deer and that, when sperm numbers are equal, it is determined mainly by sperm swimming velocity and sperm morphology.

Animals↗
PubMed1995

Natural versus chorionic gonadotropin-induced ovarian responses in the clouded leopard (Neofelis nebulosa) assessed by fecal steroid analysis.

The clouded leopard (Neofelis nebulosa) is an endangered species difficult to propagate in captivity because of sexual incompatibility between paired individuals. Fecal estradiol (E2) and progesterone (P4) metabolites were quantified in 14 females to noninvasively monitor seasonal reproductive patterns and compare ovarian responses to natural mating vs. exogenous gonadotropins. Increased E2 excretion was associated with behavioral estrus or eCG treatment, whereas elevated P4 metabolites were observed during natural and hCG-induced pregnant and nonpregnant luteal phases. On the basis of fecal E2 profiles, duration of the estrous cycle was 24 +/- 2 days, with estrus lasting 6 +/- 1 days. Mean gestation length was 89 +/- 2 days, whereas duration of the nonpregnant luteal phase was 47 +/- 2 days. Females experienced a seasonal anestrus during the late summer and early fall. One female demonstrated a lactational anestrus after the birth of three cubs. On nine occasions, clouded leopards ovulated spontaneously (based on elevated fecal P4 metabolite concentrations) in the absence of mating. Patterns of eCG-stimulated E2 excretion were similar to those associated with natural estrus and were unaffected by eCG dosage (25, 50, or 100 IU). In contrast, post-hCG P4 metabolite profiles varied considerably, with responses including anovulation, attenuated luteal P4 metabolite production, and hyperstimulated luteal function. In some females, compromised luteal function after ovulation induction appeared to be due to the presence of mature CL from previous spontaneous (without copulation) ovulations at the time of gonadotropin treatment. Duration of post-hCG P4 metabolite excretion was reduced approximately 40% in these individuals compared to females with no evidence of active luteal activity. In sum, these are the first data describing the ovarian cycle of this endangered species. The information is important because it is based on the longitudinal assessment of multiple females using a completely atraumatic approach, thereby eliminating the potential confounding impact of stress. Data indicate that spontaneous ovulations and the presence of active luteal tissue on the ovary can profoundly affect ovarian responses to exogenous gonadotropin therapy. Therefore, fecal steroid monitoring can serve as a useful adjunct to developing assisted reproduction techniques, especially the hormonal induction of ovulation for planned artificial insemination.

Animals↗