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PubMed1994

The effect of multiple transfers of immune serum on maturing Schistosoma bovis infections in calves.

To investigate the role of humoral factors in immunity, serum from cattle with naturally acquired immunity to Schistosoma bovis was injected intraperitoneally into calves that had been infected 4 weeks earlier with 10,000 S. bovis cercariae. Serum was injected weekly until 12 weeks post-infection to a total of 4,500 ml per calf and controls received normal serum or saline. No significant difference in worm or in faecal or tissue egg counts were seen in the three groups of recipients in spite of the observation that the serum donors had proved highly resistant to experimental challenge. In a second experiment, pre-infection or 4-, 8- or 12-week post-infection serum from donors given a single experimental infection with 10,000 S. bovis cercariae was injected intraperitoneally into groups of calves that had been infected 4 weeks earlier with 20,000 S. bovis cercariae. Injections were given weekly up to week 10 post-infection to a total of 2000-3500 ml serum per calf. In calves injected with immune serum there was a reduction in faecal and tissue egg counts and in the numbers of worms recovered as compared with the controls. In recipients of 8- and 12-week serum the reductions in faecal and tissue egg counts were higher than those in worm recovery, suggesting that 8- and 12-week post-infection sera contained factors capable of causing, in addition to worm death, suppression of worm fecundity. This provides further evidence of the importance of fecundity suppression in immunity to schistosomiasis.

Animals↗
PubMed1993

The effect of superoxide dismutase alleles on aging in Drosophila.

The effects of superoxide dismutase on aging were tested using two different experimental approaches. In the first, replicated populations with postponed aging were compared with their controls for frequencies of electrophoretic alleles at the SOD locus. Populations with postponed aging had consistently greater frequencies of the allele coding for more active SOD protein. This allele was not part of a segregating inversion polymorphism. The second experimental approach was the extraction of SOD alleles from different natural populations followed by the construction of different SOD genotypes on hybrid genetic backgrounds. This procedure did not uncover any statistical effect of SOD genotype on longevity or fecundity. There were large effects on longevity and fecundity due to the family from which a particular SOD genotype was derived. To detect the effects of SOD genotypes on longevity with high probability would require a ten-fold increase in the number of families used.

Aging↗
PubMed1992

Infertility in industrialized countries: prevalence and prevention.

We discuss the prevalence and aetiology of infertility and the relevance of this information for national infertility services and prevention programmes. The prevalence of infertility in industrialized countries has been said to be as high as 10-20%. This estimate, and the argument that little can be done to prevent infertility, have been used as justification for increased government investment in, or expansion of, services for medically assisted conception. However, population prevalence surveys indicate that far fewer couples of reproductive age are actually infertile. For example, a recent survey in the United States reported that 8.5% of married couples with a wife age 15-44 were infertile. 4% of the sample were childless and reported having a condition which impaired fecundity, while less than 2% were childless, had impaired fecundity and were over 35 years of age. Other studies show that nearly a third of couples have difficulty conceiving at some point during their reproductive lives but few actually remain childless. A significant proportion of infertility could be prevented through more aggressive application of standard public health measures.

Adolescent↗
PubMed1999

Social rank, stress, fitness, and life expectancy in wild rabbits.

Wild rabbits of the two sexes have separate linear rank orders, which are established and maintained by intensive fights. The social rank of individuals strongly influence their fitness: males and females that gain a high social rank, at least at the outset of their second breeding season, have a much higher lifetime fitness than subordinate individuals. This is because of two separate factors: a much higher fecundity and annual reproductive success and a 50% longer reproductive life span. These results are in contrast to the view in evolutionary biology that current reproduction can be increased only at the expense of future survival and/or fecundity. These concepts entail higher physiological costs in high-ranking mammals, which is not supported by our data: In wild rabbits the physiological costs of social positions are caused predominantly by differential psychosocial stress responses that are much lower in high-ranking than in low-ranking individuals.

Animals↗
PubMed2004

Effect of herbal molluscicides and their combinations on the reproduction of the snail Lymnaea acuminata.

Effects of sublethal treatment (20 and 60% of LC50/24 h) of the plant-derived molluscicides Annona squamosa Linn. and Lawsonia inermis Linn. and their combinations with other herbal molluscicides, such as Cedrus deodara Roxb, Azadirachta indica A. Juss, bulb powder of Allium sativum Linn. and Polianthes tuberosa Linn., and oleoresin of Zingiber officinale Rosc., and acetogenins extracted from the seeds of A. squamosa Linn., on the reproduction of the snail Lymnaea acuminata have been studied. It was observed that the plant-derived molluscicides singly and in binary combinations with other herbal molluscicides and the extracted acetogenins caused a significant reduction in the fecundity, hatchability, and survival of young snails. Withdrawal of the snails to fresh water after the above treatment caused a significant recovery in the fecundity of the snail Lymnaea acuminata. Twenty-four-hour sublethal treatment with the acetogenins caused a maximum reduction in the protein, amino acid, DNA, and RNA in the ovotestis of treated Lymnaea acuminata.

Amino Acids↗
PubMed2004

Comparison of the toxicity using body residues of DDE and select PCB congeners to the midge, Chironomus riparius, in partial-life cycle tests.

Due to the long time course required to achieve steady state with highly lipophilic contaminants such as PCBs (polychlorinated biphenyls), data derived from short-term toxicity tests may lead to an erroneous interpretation of hazard. In addition, PCBs bioaccumulated over time can cause sublethal impairments in organisms at concentrations much lower than required for mortality. Here, the body residues of 1,1-dichloro-2,2-bis-p-chlorophenyl ethane (DDE) and select PCB congeners associated with a spectrum of chronic effects in the midge, Chironomus riparius, were evaluated. The route of exposure was ingestion of the PCB-contaminated alga, Chlorella vulgarus, and trout chow loaded with the selected test compound. Two separate exposures of midges were performed. In the first experiment, midges were exposed from the second instar to the pupal stage. In the second exposure, midges were exposed from the second instar to the adult stage. A variety of sublethal endpoints was monitored, including developmental time within a stadium, body weight, and fecundity for the female adult. The dose was assessed as the whole body residue concentration of the contaminant. Overall, the midge concentration increased with increasing exposure concentration in algae and trout chow. Body weight at the end of each stadium was the assessment parameter that was least significantly affected among the test endpoints monitored. In contrast, a significant increase in development time was the endpoint that was most frequently observed in response to contaminant exposure. Reduction in fecundity was found only for DDE-exposed midges. These data, in which chronic endpoints are related to body residues, suggest that body residues will be useful in defining sublethal hazards of DDE and some PCB congeners.

Administration, Oral↗
PubMed2006

Physiological and reproductive effects of beta adrenergic receptor antagonists in Daphnia magna.

Although pharmaceuticals are increasingly found in surface waters, environmental levels of many of these compounds are not acutely toxic to model test organisms. Prior to conducting appropriate ecological risk assessments of pharmaceuticals, the mode of action-based biomarkers needs to be developed for non-target species. To evaluate toxicity of the beta-adrenergic blockers propranolol and metoprolol on non-target biota, we assessed standard ecotoxicological endpoints after 9 days of subchronic exposure in a transgenerational study with Daphnia magna. On day 9 of exposure, the lowest observed effects concentration (LOEC) for growth were 0.44 mg L(-1) for propranolol and 12 mg L(-1) for metoprolol. Total fecundity LOECs for the 9-day exposure were 0.11 mg L(-1) and 6 mg L(-1) for propranolol and metoprolol, respectively. In addition to typical ecotoxicological endpoints, we evaluated the utility of employing the physiological biomarkers of heart rate and metabolic rate following subchronic and acute exposures to propranolol and metoprolol. Propranolol and metoprolol LOECs for heart rate were 0.055 mg L(-1) and 3.1 mg L(-1), significantly lower than the LOECs for growth and reproduction. At these concentrations, heart rate was significantly lower than the control values for both compounds. Daphnia magna endpoint sensitivity to chronic propranolol and metoprolol exposure was mortality < growth < fecundity < heart rate. Second generation D. magna were less sensitive to both compounds. Responses of the physiological biomarkers heart rate and metabolic activity suggest that propranolol and metoprolol exerts sublethal toxicity to D. magna at lower concentrations than observed in the classical endpoints.

Adrenergic beta-Antagonists↗
PubMed1998

Pre- and postnatal exposure to 3,3',4,4'-tetrachlorobiphenyl: II. Effects on the reproductive capacity and fertilizing ability of eggs in female mice.

This study investigated the effects of 3,3',4,4'-tetrachlorobiphenyl (TCB) on the reproductive capacity of female mice. Female C57BL/6J mice (F-0) were fed diets containing 0, 3, or 30 ppm TCB for 2 weeks before pairing with nontreated C57BL/6J males for a 10-day breeding period. Females were continued on their treatment diet throughout mating, gestation, and lactation. Female offspring (F-1) were fed the same diet as their dams throughout the study. The reproductive capacity of F-1 females was examined by mating with non-treated B6D2-F1 males. In addition, the fertilizing ability of eggs from F-1 females was examined in vitro by insemination with sperm from nontreated B6D2-F1 males. Fecundity in F-0 females after mating was 80%, 71%, and 47% in the 0, 3, and 30 ppm treatment groups, respectively. Four-day and 21-day survival indices were lower for offspring of 30 ppm TCB-treated F-0 females than for offspring of the control females. Fecundity in F-1 females was the same among all treatment groups, however, all offspring born to 3- and 30-ppm TCB-treated F-1 females died before 4 days of age. Although the litter size at birth was not affected, the in vitro fertilizing ability of eggs in the 3- and 30-ppm treatment groups was lower than in the control group. This decrease in fertilizing ability was associated with an increase in degenerated eggs. F-0 females treated with 30 ppm TCB had enlarged livers during pregnancy and lactation. At 5 and 6 weeks, liver enlargement and thymus atrophy were apparent in F-1 females exposed to 30 ppm TCB. This study demonstrated impaired reproductive capacity and decreased egg fertilizing ability in TCB-treated female mice.

Animals↗
PubMed1999

Life-cycle toxicity of bis(tributyltin) oxide to the sheepshead minnow (Cyprinodon variegatus).

The effects of tributyltin (TBT) to the life cycle of the estuarine fish Cyprinodon variegatus were examined in a 180-day flow-through exposure. The study was initiated with embryos less than 24 h postfertilization and monitored through hatch, maturation, growth, and reproduction under continuous exposure to mean measured TBT concentrations of 5.4, 3.2, 1.3, 0.66, and 0.41 microg TBT/L. Progeny isolated at the onset of reproduction by the parental generation (F0) were monitored for survival as embryos, survival as fry/juveniles, and growth 30 days postisolation. TBT, at a concentration of 5.4 microg/L, significantly reduced embryo survival of the F0 generation sheepshead minnows. By day 145 of the exposure, significant effects to the survival of this generation increased and included all test concentrations >/=0.66 microg/L. Survival of 0.66 microg/L was reduced 59% relative to control survival by termination of the F0 generation. Growth of F0 generation organisms as measured by standard length was significantly reduced only on day 90 at 3.2 microg/L, however no significant reductions of wet or dry weight related to treatment concentration were detected. Due to complete mortality of organisms exposed to 5.4 microg/L by study day 7, effects to fecundity and progeny were monitored at measured concentrations of 3.2, 1.3, 0.66, and 0.41 microg TBT/L. Fecundity, as measured by the production of viable eggs produced per female per day, was unaffected by any of the test treatments. All F1 generation embryos isolated from treatment chambers into 3.2 microg/L died. Survival, standard length, wet and dry weight of the F1 generation at the remaining treatment concentrations were unaffected. The results of this study indicate that exposure to TBT reduced survival of the F0 generation sheepshead minnow and establishes the lowest observed effect concentration (LOEC) as 0.66 microg TBT/L, and the no observed effect concentration (NOEC) as 0.41 microg TBT/L for this species.http://link.springer-ny. com/link/service/journals/00244/bibs/37n2p258.html

Aging↗
PubMed2000

Effect of different combinations of MGK-264 or piperonyl butoxide with plant-derived molluscicides on snail reproduction.

Effect of sublethal treatment (20% and 60% of LC(50)/24 h) of plant-derived molluscicides, viz. Polianthes tuberosa, Trachyspermum ammi, Allium sativum powder; Azadirachta indica oil; oleoresin of Zingiber officinale; and their active molluscicidal component in combination (1:5) with MGK-264 or piperonyl butoxide on the reproduction of snail Lymnaea acuminata have been studied. It was observed that the combination of plant derived molluscicide and their active molluscicidal components, viz. tigogenin, hecogenin, azadirachtin, allicin, thymol, and [6]-gingerol combination with MGK-264 or piperonyl butoxide caused a significant reduction in fecundity, hatchability, and survival of young snails. Withdrawal of snails to fresh water after the above treatment caused a significant recovery in the fecundity of L. acuminata.

Animals↗
PubMed2003

Influence of water allocation and freshwater inflow on oyster production: a hydrodynamic-oyster population model for Galveston Bay, Texas, USA.

A hydrodynamic-oyster population model was developed to assess the effect of changes in freshwater inflow on oyster populations in Galveston Bay, Texas, USA. The population model includes the effects of environmental conditions, predators, and the oyster parasite, Perkinsus marinus, on oyster populations. The hydrodynamic model includes the effects of wind stress, river runoff, tides, and oceanic exchange on the circulation of the bay. Simulations were run for low, mean, and high freshwater inflow conditions under the present (1993) hydrology and predicted hydrologies for 2024 and 2049 that include both changes in total freshwater inflow and diversions of freshwater from one primary drainage basin to another. Freshwater diversion to supply the Houston metropolitan area is predicted to negatively impact oyster production in Galveston Bay. Fecundity and larval survivorship both decline. Mortality from Perkinsus marinus increases, but to a lesser extent. A larger negative impact in 2049 relative to 2024 originates from the larger drop in fecundity under that hydrology. Changes in recruitment and mortality, resulting in lowered oyster abundance, occur because the bay volume available for mixing freshwater input from the San Jacinto and Buffalo Bayou drainage basins that drain metropolitan Houston is small in comparison to the volume of Trinity Bay that presently receives the bulk of the bay's freshwater inflow. A smaller volume for mixing results in salinities that decline more rapidly and to a greater extent under conditions of high freshwater discharge.Thus, the decline in oyster abundance results from a disequilibrium between geography and salinity brought about by freshwater diversion. Although the bay hydrology shifts, available hard substrate does not. The simulations stress the fact that it is not just the well-appreciated reduction in freshwater inflow that can result in decreased oyster production. Changing the location of freshwater inflow can also significantly impact the bay environment, even if the total amount of freshwater inflow does not change.

Animals↗
PubMed2002

Fasciola hepatica (Trematoda: Digenea): its effect on the life history traits of Pseudosuccinea columella (Gasteropoda: Lymnaeidae), an uncommon interaction.

An uncommon snail-trematode interaction pattern was found for the Pseudosuccinea columella - Fasciola hepaticamodel under laboratory conditions. Week-old juveniles from two isolates showed very high rates of infection (90.0% and 93.3%) after exposure to five miracidia. They also showed differences in their life history traits when compared to a control group. However, they did not exhibit the increase in size and reduction/cessation in host fecundity which is usually observed in most of the other related snail-trematode systems. In contrast, infected juvenile P. columella showed increased egg laying after the onset of cercarial emission and there was no effect on growth. A third isolate of P. columella was found to be refractory to miracidial infection. This constitutes the first report of non-susceptibility to F. hepatica in a lymnaeid species which is usually susceptible. These non-susceptible snails exhibited lower fecundity and survival compared to non-exposed susceptible snails under identical laboratory conditions. The differences observed in terms of life span and reproduction could result from the cost of resistance for individuals from this isolate.

Age Factors↗
PubMed2002

Effects of sex and age on the susceptibility of C57BL/6J mice to infection with Brachylaima cribbi and the course of infection in NOD SCID mice.

The C57BL/6J strain of Mus musculus is susceptible to the terrestrial trematode Brachylaima cribbi. The duration of infection in these mice is generally 9-12 weeks with a peak excretion of eggs at 4 weeks post-infection (wpi). The effects of age and sex on the course of infection were investigated by comparing infections in male and female mice aged 8 or 28 weeks at the time of infection. There were no significant differences in the susceptibility of the adolescent mice of either sex or older male mice. However, older, mature female mice were significantly more resistant to B. cribbi infection than older mature males and adolescent females with reduced worm burden, fecundity and egg fertility. In comparison with young males, all three parameters were again reduced but this was only significant statistically for reduced egg fertility. It is likely that mature female sex hormones influence resistance to B. cribbi infection. The susceptibility of immunodeficient NOD SCID mice was evaluated and compared with C57BL/6J mice. NOD SCID mice were susceptible to B. cribbi infection with the infection persisting with a relatively unchanged worm burden for the life of the mouse with the longest surviving mice being 31 wpi. The life-span of B. cribbi is therefore at least 31 weeks. There were no significant differences in egg excretion, worm burden or fecundity among NOD SCID mice at 4, 8 or 18 wpi. As the infection progressed in NOD SCID mice, the location of worms in the small intestine moved from the anterior third in the early stages of the infection to the mid- to posterior intestine in the later stages. Comparison of the infection in NOD SCID mice with C57BL/6J mice indicates that the expulsion of worms in the latter is mediated by an immune response.

Aging↗
PubMed2000

The crucial role of granulocytes in the early host defense against Strongyloides ratti infection in mice.

The involvement of granulocytes in the host early defense against the nematode, Strongyloides ratti, was studied. It was confirmed that granulocytes were effectively depleted for 4 days by anti-granulocyte monoclonal antibody (anti-Gr-1). To examine the involvement of granulocytes in the host defense against migrating larvae, 2,000 S. ratti infective larvae (L3) were inoculated subcutaneously 1 day after antibody treatment. The number of S. ratti eggs secreted in feces (EPG) was higher in the granulocyte-depleted group than in the control group. The number of migrating larvae also increased in the granulocyte-depleted group in accordance with the increase in EPG. Therefore granulocytes are crucial for the host early defense against migrating larvae of S. ratti. Next, the involvement of granulocytes in the intestinal early defense was examined. Mice were treated with the antibody on day 3 post-infection. On that day, almost all inoculated larvae reached the intestine and molted to become adults. EPG on day 5 post-infection was increased by the antibody treatment, but no effect was observed on intestinal worm numbers. The fecundity (EPG/worm number) of S. ratti adult worms in the granulocyte-depleted group was higher than that in the control group. Thus granulocytes are also involved in the intestinal early defense through suppressing fecundity of the adult worms. On the other hand, the depletion of granulocytes had no effect on the late adaptive response against S. ratti adult worms (e.g. number of intestinal mucosal mast cells, time of worm expulsion). These results suggest that granulocytes are mainly involved in the host early defense against parasites.

Animals↗
PubMed1997

Ascaridia galli populations in chickens following single infections with different dose levels.

In all, 3 groups of 20 Lohman Brown chickens aged 1 day were orally infected with doses of 100, 500, or 2,500 embryonated Ascaridia galli eggs, respectively. After 8 weeks, egg counts (eggs per gram of feces, EPG) were determined for all animals prior to slaughter. The gastrointestinal tracts were examined for the presence of adult and immature stages of A. galli. All groups had roughly similar worm burdens and, hence, significantly different establishment rates of 14.2%, 2.9%, and 0.5%, respectively. A significantly lower mean female worm burden was seen in the high-dose group (P = 0.02), which also showed a significantly lower level of egg excretion (P = 0.01). However, fecundity (EPG per female) did not significantly differ between the groups (P = 0.55). The mean lengths of adult worms as well as the weight of the mean worm burdens were significantly smaller in the high-dose group. This study demonstrated that single infections with varying doses of A. galli eggs influenced the establishment rate, sex ratio, egg excretion, and worm size and weight but not the worm fecundity.

Animals↗
PubMed2002

Adaptive reproductive variation along a pollution gradient in a wolf spider.

When populations are exposed to environmental pollutants, growth and reproduction might be strongly reduced due to an increased detoxification effort. Sublethal metal pollution is therefore to be expected to cause the same selection pressure as a low resource habitat and might alter the reproductive strategy. Optimality models of life history theory predict that when resource availability is reduced, growth and reproductive output are reduced and that the release of fewer but larger propagules will be favoured. This was tested by applying a life history model to reproductive trait measurements in six populations of the wolf spider Pirata piraticus in which the assumptions of the model are satisfied. Internal Cd, Cu and Zn body burden were strongly correlated with each other, and differed strongly between the populations, indicating consistently differing metal exposure at the different sites. Pb levels were extremely variable within each population and did not differ between the populations. Females from populations with high concentrations of the first three heavy metals showed a strongly reduced reproductive output and fecundity, indicating a high reduction in resource availability due to detoxification processes. Egg size in contrast was negatively correlated with fecundity and reproductive output and as a consequence positively related with internal metal burden. Our results are thus in strong agreement with the predictions of the optimality models and confirm the benefits of a larger propagule size when resource availability is reduced.

Adaptation, Physiological↗
PubMed2003

Consumption of snowdrop lectin (Galanthus nivalisagglutinin) causes direct effects on adult parasitic wasps.

Honeydew is a common sugar-rich excretion of aphids and other phloem-feeding insects and represents the primary sugar in many agricultural systems. When honeydew-producing insects feed on genetically modified plants, the honeydew can contain amounts of the transgene product. Here we address whether this route of exposure poses a risk for non-target insects. Three species of parasitic wasps were selected: i.e. Aphidius colemani, Trichogramma brassicae and Cotesia glomerata, all of which are known to use honeydew as a carbohydrate source in the field. Wasps were fed sucrose solutions with varying concentrations of snowdrop lectin ( Galanthus nivalisagglutinin, GNA), a protein that has been engineered into crops to confer resistance against homopteran pests and that has been detected in honeydew. Parameters evaluated included gustatory response, longevity, fecundity, progeny emergence and sex ratio. While A. colemani and T. brassicae, but not C. glomerata, were able to detect GNA, this gustatory recognition had no effect on the acceptance of a GNA-sucrose solution. In all three species, GNA ingestion reduced parasitoid survival significantly. However, in respect to fecundity, negative effects were observed for T. brassicae but not for A. colemani. The results suggest that the effect of GNA consumption may depend on the specifics of a parasitoid's biology, especially its longevity and its mode of egg maturation.

Animals↗
PubMed2003

Phenological variation as protection against defoliating insects: the case of Quercus robur and Operophtera brumata.

Phenological synchrony between budburst and emergence of larvae is critical for the fitness of many spring-feeding insect herbivores. Therefore, large intraspecific variation in timing of budburst of the host may have a negative effect on the herbivore. We studied how asynchrony between emergence of larvae and budburst affects the fitness of Operophtera brumata (Lepidoptera: Geometridae), a major defoliator of Quercus robur, which can adapt to the phenology of a single tree. It is known that, in maturing leaves of Q. robur, accumulation of condensed tannins has a negative effect on growth of O. brumata. However, there is no information about the effect of hydrolysable tannins and other phenolics that are potential antifeedants. In this study, we also analysed changes in secondary chemistry of the foliage of Q. robur and how different compounds are correlated with growth and survival of O. brumata. The effect of asynchrony on O. brumata was studied in rearing experiments. The neonate larvae were incubated without food for different periods of time. The decline in nutritional quality of foliage was estimated by rearing cohorts of larvae with manipulated hatching times on the leaves of ten individual Q. robur trees. For the chemical analysis, the foliage of these trees was sampled at regular intervals. In the absence of foliage, mortality of neonate larvae started to increase exponentially soon after the larvae emerged. If the larvae missed budburst, the decline in nutritional quality of the foliage led to increased mortality and lower body mass (= fecundity). Hydrolysable tannins were not significantly correlated with performance of the larvae. Only condensed tannins were found to correlate negatively with the growth and survival of O. brumata. Certain individual trees were unsuitable hosts for O. brumata because the decline in quality of the foliage was very rapid. Based on regression equations for increasing rate of mortality and decreasing fecundity, we calculated that a relatively small mismatch of +/-30 degree days between budburst and hatching of larvae leads to a 50% decrease in the fitness of O. brumata. Thus, large phenological variation within a Q. robur stand can limit the colonisation of neighbouring trees by dispersing larvae. Furthermore, the hybridisation of moths adapted to phenologically different trees may lead to maladapted phenology of their offspring.

Adaptation, Physiological↗