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PubMedDate not supplied

Effect of 5alpha-dihydrotestosterone implants on the fertility of male rats treated with tamoxifen.

In adult male rats, tamoxifen (TAM) reduces circulating levels of luteinizing hormone (LH) and testosterone (T) with no effect on follicle-stimulating hormone (FSH) and prolactin (PRL). It reduces the male rat's ability to inseminate the female (potency), as well as its siring ability (fecundity). The objective of the present study was to test whether androgen supplementation could reverse all or some of the observed effects of TAM. To obviate the effects of estrogen, the study was designed to evaluate the beneficial or deleterious effect of 5alpha-dihydrotestosterone (DHT), a 5alpha-reduced, nonaromatizable metabolite of T, on the reproductive functions of TAM-treated adult male rats. Adult male rats received either saline or TAM (0.2 or 0.4 mg per day p.o.) for 90 days. A group of TAM-treated rats was implanted with 6 mg DHT from day 50 to day 90. A third group of untreated animals was implanted with 0-, 1-, 3-, or 6-mg DHT implants for 90 days. Mating studies were done to assess the fecundity, potency, and fertility index at the end of the treatment. Weights of testes, pituitary, and accessory sex organs were recorded, and circulating levels of LH, FSH, PRL, T, and 17-beta-estradiol were estimated. DHT did not affect the fecundity or fertility index. TAM reduced fecundity, potency, and the fertility index. DHT implants improved the fertilizing ability of the TAM-treated male rat. This study discusses and reviews the role of T and 17-beta-estradiol in sperm-fertilizing potential in light of these observations.

Animals↗
PubMed2000

Effects of Photofrin II on adults of Eretmapodites quinquevittatus.

This research was conducted to further assess the efficacy of photosensitizers as adult mosquito control agents. Fourth-stage larvae of Eretmapodites quinquevittatus were fed Photofrin porfimer sodium (PII) (< or = 3.75 microg/ml) and the resulting adults (parentals) were photoirradiated. These parentals were mated with untreated controls and resulting 1st generation (F1) progeny were inbred. Comparisons of fecundity and fertility were made between parentals and resulting F1 progeny. Interbred F1 adults survived significantly longer than parentals (P > 0.05). Parental females laid fewer eggs than F1 females, and parental eggs hatched at a significantly lower rate than eggs of F1 females (P < 0.01). Neither PII nor any effects of PII seem to be transferred from parent to offspring. Reduced fecundity and fertility may be due to reduced energy levels caused by exposure to PII. Experimental adults fed PII exhibited significantly reduced survivorship when compared to untreated controls (P < 0.001). Fertility did not differ when compared to controls, but experimental adult fecundity was significantly less than control fecundity for the constant photoirradiation group.

Animals↗
PubMed2001

A demographic analysis of fire-stimulated seedling establishment of Sarracenia alata (Sarraceniaceae).

Recurring fires are thought to be critical to maintaining populations of carnivorous plants in wet pine savannas. Nevertheless, the impact of fire on population dynamics of these unique and sometimes rare plants is poorly understood. In this study, I analyzed stage-structured matrices for Sarracenia alata. To examine the effects of fire-stimulated increases in seedling establishment, five matrices were constructed, which differed in fecundity rates associated with different fire frequencies (annual fires, 1/3, 1/7, 1/20, and 0/20 yr). In addition, I analyzed the sensitivity of population growth and dynamics to changes in other vital rates. Fire-stimulated increases in fecundity were not necessary to maintain viable populations of Sarracenia alata. Although increases in fecundity increased population growth rate, all five fire frequencies (including the "no-fire" scenario) produced either stationary or increasing populations. Adding year-to-year stochasticity in vital rates did not alter these general trends. Population growth and decline were much more sensitive to reductions in the survival of large adult ramets (which were projected to have a life expectancy of 59 yr). Population growth was also more sensitive to changes in juvenile persistence than to juvenile growth, suggesting that conservative use of captured resources by juveniles has a greater impact on fitness than rapid growth and maturation. Given that a previous study showed that modest variation in fire frequency had no impact on either adult or juvenile survival, I conclude that Sarracenia alata relies on fire-regulated plasticity in allocation to pitchers to increase the survival and lifetime fecundity of iteroparous ramets.

Journal Article↗
PubMed1992

The effect of laparoscopic ablation or danocrine on pregnancy rates in patients with stage I or II endometriosis undergoing donor insemination.

The effect of treatment on stages I and II endometriosis was evaluated in 61 women with laparoscopically proven disease who were undergoing therapeutic donor insemination. Only treatment cycles completed after diagnostic laparoscopy were used for analysis. To evaluate fecundity, we performed life-table analysis on 343 treatment cycles of therapeutic donor insemination in 67 patients with stage I or II endometriosis and compared it with 212 cycles in 43 patients with no female infertility factors. Average monthly fecundity and cumulative conception rates over six cycles were calculated for each group. A significant difference was found when patients with laparoscopically proven normal anatomy were compared with those with endometriosis (P = .002). The fecundity did not differ significantly between stage I and stage II endometriosis (P greater than .05). Neither ablation during laparoscopy nor medical treatment with danocrine improved the fecundity of patients with early-stage endometriosis (P greater than .05).

Adult↗
PubMed2003

[Reproductive biology of Macrobrachium nipponensis in Lake Wuhu].

Macrobrachium nipponensis is a key species of freshwater shrimps in China. To know its reproductive biology is very important for its protection and rational use. Studies from September 1998 to September 1999 in LakeWuhu showed that the spawning ground of M. nipponensis was situated in the littoral zone of the whole lake. The main spawning period of overwintering shrimps was from mid-April to mid-July (water temperature 20.5-31 degrees C), and that of non-overwintering shrimps was from mid-July to mid-September (water temperature 31-23 degrees C). The sex ratio (female:male) increased gradually during the spawning period, and the absolute fecundity of overwintering shrimps was higher than that of non-overwintering ones. The relationship between absolute fecundity and body length and between absolute fecundity and body weight could be expressed as cubic equation and simple linear equation, respectively. The relative fecundity (RW) of M. nipponnensis could regard as a constant, and its 95% confidence limits was 1067.76 +/- 16.94 eggs.g-1.

Animals↗
PubMed2004

[Effects of low and subzero temperature on a Plutella xylostella laboratory population].

In this study, the effects of low (< 8 degrees C) and subzero temperature on the development, survival and reproduction of Plutella xylostella were examined. The mortality of its egg and pupae at 4 degrees C and 6 degrees C increased with time, no egg and pupae could complete their development at these low temperatures, and all died after 55 days and 70 days, respectively. When the pupae were placed at 4 degrees C and 6 degrees C for various durations and then moved to 16 degrees C for development, the fecundity of the resultant adults was reduced, and the longer the duration at 4 degrees C and 6 degrees C, the further the fecundity was reduced, and the fecundity was reduced to zero when the pupae were retained at these low temperatures for 45 days. The survival of this insect was observed following exposure of various stages of this insect to temperatures below 0 degree C. The results showed that the mortality of all preimaginal stages increased with decreased temperature and prolonged duration. The ability of cold tolerance of the various stages of this insect was in order of the third instar and pupa > the second and forth instars > the first instar and egg. Temporal exposure to temperatures below 0 degree C affected the development of subsequent stages at a favorable temperature. Generally, the developmental time of the subsequent stages increased, and the largest increase of development time was observed with the stage next to the stage treated at low temperatures. Exposure of the pupal stage to low temperature also reduced the fecundity of the resultant female adults, and the reduction was positively correlated to lower temperature and longer exposure.

Animals↗
PubMed2004

Antagonistic effects of energy status on meal size and egg-batch size of Aedes aegypti (Diptera: Culicidae).

The effect of sugar feeding on egg-batch size in Aedes aegypti was examined in a way that would distinguish between the roles of a recent sugar meal (full vs. empty crop) and of repeated sugar feeding and digestion (high vs. low energy reserves). Egg numbers of females representing the four combinations of these characteristics (full crop/high reserves, full crop/low reserves, empty crop/high reserves, empty crop/low reserves) were counted during their first gonotrophic cycle. In addition, the sizes of their replete sugar meals and human blood meals were measured to understand the interactions between them. Results demonstrated that blood-fed mosquitoes with full crops and low energy reserves produced the fewest eggs (mean = 56.2); those with empty crops and high energy reserves produced the most eggs (mean = 84.6); and those with the opposite combinations (full/high and empty/ low) had an intermediate fecundity (mean = 75.2 and 76.9, respectively). This ranking of fecundities did not correspond to blood-meal size ranks, owing to direct and indirect effects of energy reserves on meal sizes and egg number. Full-crop females with low reserves ingested the smallest blood meals (mean = 0.62 mg) and had the lowest fecundities. Full-crop females with high reserves ingested more blood (mean = 0.82 mg) and produced more eggs. But empty-crop females with low reserves ingested the largest blood meals (mean = 1.19 mg), yet produced significantly fewer eggs than their high-reserve counterparts, which took smaller blood meals (mean = 0.99 mg). These results demonstrate extremes in the reproductive penalty of crop sugar and the reproductive reward of digested sugar. Energy reserves and an empty crop are similarly valuable in promoting fecundity at the time blood is taken.

Aedes↗
PubMedDate not supplied

Evolutionary genetics of aging in Daphnia.

Evolutionary theory of aging stipulates that aging is inevitable consequence of low effectiveness of natural selection acting on traits expressed late in the life span of the organisms. Two main hypotheses exist: the neutralist mutation-accumulation theory and selectionist antagonistic pleiotropy theory. Both theories predict the increase of genetic variance with age; the antagonistic pleiotropy theory also predicts negative genetic correlation between fitness related traits in the beginning and in the end of the life span. In order to test these predictions we measured life expectancy and age specific mortality in cohorts of 26 c lones of Daphnia magna extracted from a single cyclic parthenogen population. Simultaneously, fecundity and age to maturity were measured in representatives of the same clones. Log mortality increased linearly with age, with little evidence for leveling off, although some replicate cohorts did show a significant leveling off of mortality. Genetic variance of log mortality was significantly higher in the last quarter of the life span than in earlier time intervals. There was a significant positive genetic correlation between early fecundity and early mortality, but not between early fecundity and late mortality. This indicates that, although there is a trade-off between fecundity and survival, this trade-off is not based on pleiotropy across ages and therefore the data does not support the prediction of antagonistic pleiotropy theory.

Animals↗
PubMed2005

[Estrogen receptor as a candidate gene for prolificacy of small tail Han sheep].

Single nucleotide polymorphism in exon 1 of the estrogen receptor (ESR) gene was detected by PCR-SSCP in both high fecundity sheep breeds (Small Tail Han sheep, Hu sheep and German Mutton Merino sheep) and low fecundity sheep breeds (Dorset sheep,Suffolk sheep). Results indicated that there were three genotypes (AA, AB and BB) in all three high fecundity sheep breeds, but only two genotypes (AA, AB) in both low fecundity breeds. In Hu sheep,German Mutton Merino sheep, Small Tail Han sheep, Suffolk sheep and Dorset sheep,the frequency of allele A was 0.672, 0.786, 0.846, 0.857 and 0.867, respectively, and the frequency of allele B was 0.328, 0.214, 0.154, 0.143, and 0.133, respectively. Sequencing revealed a C-->G mutation at 363 bp of exon 1 of ESR gene in the BB genotype in comparison to the AA genotype. The genotype distribution was significantly different between Small Tail Han sheep and Hu sheep (P<0.01) and between Dorset sheep and Hu sheep (P <0.05). There was no difference in genotype distribution between other sheep breeds. The Small Tail Han sheep ewes with genotypes AB or BB had 0.51 (P < 0.05) and 0.7 (P < 0.05) more lambs than those with genotype AA, respectively. These results showed that the estrogen receptor locus is either a major gene that influences the prolificacy in Small Tail Han sheep or in close linkage with such a gene. In view of our results, marker-assisted selection using ESR is warranted to increase litter size in sheep and will be of considerable economic value to mutton producers.

Alleles↗
PubMed2006

[The mechanism of the effect of apterous56f mutation on the reproductive function of Drosophila melanogaster].

The effects of L-dihydroxyphenylalanine (L-DOPA) and 20-hydroxyecdysone (20E) were studied with respect to the content of dopamine (DA), intensity of the juvenile hormone (JH) degradation, and fecundity of the wildtype flies (Canton S) and JH-deficient apterous56f mutants (in young females, carrying this mutation, the levels of DA and 20E production were strongly increased). Fly feeding with L-DOPA proved to increase the level of DA in a dose-dependent manner and reduce JH degradation in 2-day-old females of both strains. Feeding with 20E produced the same effect. Treating the wild-type flies with 2.5 mg L-DOPA caused a 24-h delay in beginning of oviposition and reduction in fecundity throughout the experiment. An L-DOPA dose of 1 mg caused no such changes. An experimental increase in 20E titer led to reduced fecundity of the wild-type flies, though no delay in oviposition was observed. In mutant flies, an increase in DA and 20E levels accelerated beginning of oviposition and increased fecundity of young females, though the latter parameter was reduced in mature individuals. Thus, an increase in endogenous DA and 20E characteristic of young apterous56f females is assumed to be a compensatory response that leads to a higher JH titer and induction of vitellogenesis.

Animals↗
PubMed2005

Comparative study on biological parameters of Bemisia tabaci (Genn.) collected on four host plants from Varamin-Iran.

During 2003 biological parameters of sweetpotato whitefly, B. tabaci (Genn.) (Horn. Aleyrodidae) as a major pest of field crops, vegetables and ornamentals were studied. In this study, the infested leaves of cucumber (Cucumis sativus L.) zucchini (Cucurbita pepo L.) eggplant (Solanum melongena L.) and cotton (Gossypium hirsutum L.) with whitefly nymphs and pupae were collected from Varamin-Iran, and were transferred to the laboratory. The newly emerged males and females of each population were released separately into a large cage set on cotton plants. Experiments were carried out in a growth chamber on cotton, (Varamin 76 variety) at 24+/-2 degrees C, 55+/-3% RH and 16:8 h (L: D) photoperiod. The adults of every collected population after emergency were reared in the large cages (40 x 50 x 70) containing pots of cotton plant. The preimaginal developmental time and reproductive parameters of 40 mated females were calculated for each population. The results revealed that the intrinsic rates of increase (r(m)), on cucumber, zucchini, eggplant and cotton were 0.093, 0.068, 0.085 and 0.078 respectively, gross fertility rate, were 67.92, 59.08, 76.13 and 63.14 respectively and mean generation time (T(c)) were 27.4, 27.74, 27.73 and 27.52 days respectively. Other demographic parameters such as intrinsic birth rate (b), intrinsic death rate (d), finite rate of increase (lambda), doubling time (DT), net fecundity rate, net fertility rate , gross fecundity rate, mean age gross fecundity and fertility, mean age net fecundity and fertility, mean age hatch, number of eggs/female/day and daily reproductive rate were also calculated. The results revealed that there were not significant differences between parameters of demography in different populations and the host plant has no significant influence on biological parameters.

Animals↗
PubMed2006

Conspecific interference by adults in an aphidophagous ladybird Propylea dissecta (Coleoptera: Coccinellidae): effect on reproduction.

The effects of conspecific adult interference on the reproductive output of an aphidophagous ladybird, Propylea dissecta (Mulsant) were investigated. Ovipositing females were subjected to physical interference with conspecific adults (0 to 4 males or females) in Petri dishes and the effects on egg cannibalism, oviposition and egg viability were recorded. The absence of interference was related to the lowest egg cannibalism (0.00%) and higher fecundity (336.30+/-32.16 eggs) and egg viability (95.83+/-1.60%). Fecundity decreased with increasing physical interference from either sex. Egg viability declined with increasing male density, but was not influenced by conspecific females. In a second experiment, evaluating the role of conspecific adult chemical tracks on fecundity and egg viability, it was observed that adult chemical track density (fresh and ten-day-old) was negatively correlated. Egg viability was not affected by the presence of adult chemical tracks. The decrease in fecundity was not affected by the sex of the adults making the tracks, thus revealing that the chemical constitution of these deterrent compounds was not sex-specific. Conspecific interference in a Petri dish reduces reproductive output, as a result of physical interference and response to what seem to be oviposition-deterring pheromones present in adult tracks.

Animals↗
PubMed2006

Effects of competition on the fitness of wild and crop-wild hybrid sunflower from a diversity of wild populations and crop lines.

Gene flow between crop fields and wild populations often results in hybrids with reduced fitness compared to their wild counterparts due to characteristics imparted by the crop genome. But the specifics of the evolutionary outcome of crop-wild gene flow may depend on context, varying due to local environmental conditions and genetic variation within and among wild populations and among crop lines. To evaluate context-dependence of fitness of F1 hybrids, sunflower crop lines were crossed with nine wild populations from across the northern United States. These crop-wild hybrids and their wild counterparts were grown under agricultural conditions in the field with and without wheat competition. Hybrids were far less fecund than wild plants, yet more likely to survive to reproduce. There was considerable variability among wild populations for fecundity and the specific crop line used to generate the crop-wild hybrid significantly affected fecundity. The fitness deficit suffered by crop-wild hybrids varied by population, as did the rankings of the crop-wild hybrids from three different crop lines. Wheat competition decreased fecundity and survival considerably and hampered seed production of wild plants more than that of hybrids. Genotype x environment interactions indicated that the response of fitness to competition differed by population. Consequently, the fitness of hybrids relative to wild plants varied considerably among wild populations and was not consistent across environments. Notably, relative fitness of hybrids was greater under competitive conditions. This research is the first study of its kind to demonstrate that the consequences of crop-wild gene flow are context dependent and contingent on the genetics of the specific wild populations and the local biotic and abiotic conditions.

Biodiversity↗
PubMed1977

[Magnesium in animal and human reproduction].

The literature concerned with the amount of magnesium in genital organs and products of sexual activity is analysed in the first chapter; these data are compared with those concerning other organs and replaced in a comprehensive view of the body, related or not with the medium. It is likely that magnesium plays a role in ovule maturation, sperm viability and fecundation in Invertebrates and Fishes. In Birds and Mammals, it appears to be necessary for fecundation. In the Discoglossus (Anurian Amphibian), the deficiency and the excess in Mg2+ reduce development and influence the growth of the body and the ovary. In the Rat, the pregnancy cannot be normal, unless the food contains an adequate supply of magnesium. Severe or mild deficiencies affect the site of fetal implantation and, if they are prolonged, lead to abortion in the first instance and pathological disorders in the latter. An ionic determination of sex has been established in various animal species and in Man. In some marine Invertebrates, and in the Discoglossus, changes in ionic concentration of the breeding medium carried out immediately after fecundation induce, at will, a majority of one sex or the other; in various Mammals and in Man, variations in the composition of mineral food administered to the female before fecundation may also induce changes in the sex ratio of the progeny.

Animals↗
PubMedDate not supplied

[Effect of the photoperiod and temperature on the fertility of different generations of the blood-sucking fly, Culicoides pulicaris punctatus (Ceratopogonidae)].

It was established that the fecundity of females of different generations of C. p. punctatus, which are at the 1st gonotrophic cycle, is unequal. There was noted a decrease of the per cent of realisation of potential fecundity in females of the summer-autumn generation. The dependence of the virtual fecundity on the day length and temperature was studied. The differences in ther effect of these factors on the fecundity of females of the spring-summer and summer-autumn generations were found.

Animals↗
PubMedDate not supplied

Does ovulation stimulation improve fertility in women with minimal/mild endometriosis after laser laparoscopy?

Cycle fecundity was retrospectively analyzed in a group of infertile women after minimal/mild endometriosis had been treated by carbon dioxide laser laparoscopy. Patients were followed in spontaneous (observation) cycles as well as in treatment cycles using ovulation stimulation. Treatment protocols included clomiphene citrate (CC), sequential CC/human menopausal gonadotropins/human chorionic gonadotropin (CC/hMG/hCG), and hMG/hCG. Some patients who failed to conceive with ovulation stimulation protocols underwent in vitro fertilization (IVF). Eighty-nine patients were followed for a total of 605 cycles, during which 37 pregnancies occurred. Cycle fecundity was 0.028 in observation cycles, and was higher with the use of CC (0.066), and significantly higher (P < .05) with use of CC/hMG/hCG (0.114) and hMG/hCG (0.073). The highest cycle fecundity was attained in IVF cycles (0.222). This retrospective analysis suggests that active ovulation management in patients with minimal/mild endometriosis treated by carbon dioxide laser laparoscopy may significantly increase cycle fecundity.

Adult↗
PubMed1993

Use of infertility services in the United States.

OBJECTIVE: To examine the characteristics of women in the 1988 National Survey of Family Growth who reported having obtained medical services for impaired fecundity. METHODS: From a national sample of 8450 women between the ages of 15-44, drawn from the civilian, noninstitutionalized population of the entire United States in 1988, we estimated the use of infertility services in the United States. Multivariate statistical modeling was used to identify the characteristics associated with use of infertility services among the 770 women who reported impaired fecundity in this survey. RESULTS: Of all women with impaired fecundity, 43% had obtained some form of infertility service and 24% had obtained specialized infertility treatment--ovulation drugs, treatment of fallopian tubes, artificial insemination, or in vitro fertilization. Older, white, married women of higher socioeconomic status were most likely to have obtained specialized services, and a history of endometriosis was also strongly associated with having received such services. CONCLUSION: Most women with impaired fecundity had not obtained infertility services. Use of specialized services was strongly associated with certain sociodemographic variables or a history of endometriosis.

Adolescent↗
PubMed1996

Menstrual and reproductive history of mothers of galactosemic children.

OBJECTIVE: To test the hypothesis that female carriers of the galactosemia gene (mothers of galactosemic children) experience impaired fecundability and earlier age at natural menopause. DESIGN: Retrospective cohort study comparing experiences of mothers of galactosemic children with mothers of children with phenylketonuria (PKU). Data collection consisted of a structured telephone interview with sections on menstrual, reproductive, and medical histories. PARTICIPANTS: One hundred three galactosemia carriers and 116 PKU carriers (mean age 35.0 and 38.4 years, respectively), recruited from 38 metabolic disease clinics throughout the United States. MAIN OUTCOME MEASURES: Time-to-pregnancy (a measure of fecundability), menstrual cycle patterns, and natural menopause. RESULTS: No difference was seen between carriers of the galactosemia and the PKU gene in history of > or = 12 months of unprotected intercourse without a pregnancy, physician-diagnosed infertility, or amenorrhea lasting > 6 weeks. The fecundability ratio, adjusting for age and smoking before most recent pregnancy, was 1.17 (95% confidence interval [CI] 0.85 to 1.61). By age 45, 11% of galactosemia carriers who had not had a hysterectomy reported a natural menopause compared with 4% of PKU carriers (risk difference 7.2%, 95% CI -12.7% to 27.1%). CONCLUSION: Fecundability and other measures of fertility did not differ between mothers of galactosemic children and mothers of children with PKU. Suggestions of an earlier age at natural menopause can not be addressed definitively in this cohort because of the small number of participants who were currently age 45 years or older but may warrant additional assessment as the cohort ages.

Adult↗