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At least 19 recordsLinked to original sources
PubMed2004

Multiple infection with Wolbachia inducing different reproductive manipulations in the butterfly Eurema hecabe.

Wolbachia are rickettsial intracellular symbionts of arthropods and nematodes. In arthropods, they act as selfish genetic elements and manipulate host reproduction, including sex-ratio distortion and cytoplasmic incompatibility (CI). Previous studies showed that infection of feminizing Wolbachia and CI Wolbachia sympatrically occurred in the butterfly Eurema hecabe. We demonstrate that feminization-infecting individuals can rescue sperm modified by CI-infecting males. Phylogenetic analysis revealed that feminized individuals are infected with two distinct Wolbachia strains: one is shared with CI-inducing matrilines, and the other is only found in feminized matrilines. Therefore, the simultaneous double manipulation, CI rescue and feminization, is caused by different Wolbachia strains in feminized individuals, not by a single Wolbachia with two functions. This is the first finding of double infection of Wolbachia with different reproductive manipulations.

Animals↗
PubMed2025

Wolbachia Host Shifts and Widespread Occurrence of Reproductive Manipulation Loci in European Butterflies.

Wolbachia is the most frequent bacterial endosymbiont of arthropods and nematodes. Although it is mostly vertically transmitted, from parent to offspring through the egg cytoplasm, horizontal transfer of Wolbachia is thought to be common over evolutionary timescales. However, the relative frequency of each transmission mechanism has not been studied systematically in closely related species. Additionally, while Wolbachia is generally regarded as a reproductive manipulator, it is unclear how frequently the symbiont induces such effects. In this study, we investigated the presence, phenotypes and phylogenetic relationships among Wolbachia strains in whole genome sequence data for 18 European butterfly sister-species pairs. We find that sister-species share Wolbachia strains more often than random species pairs and that the probability of strain sharing is higher for younger pairs of host species, especially those with greater range overlap. We also find that split times between Wolbachia strains that infect the same sister-species pair generally pre-date host divergence, ruling out co-divergence in favour of horizontal transfer. However, some strains are younger than the mitochondrial split times of their hosts, so introgressive transfer cannot be ruled out in some cases. In addition, all newly assembled Wolbachia genomes contained putative homologues of genes associated with cytoplasmic incompatibility and male killing. This supports the potential for reproductive manipulation in Wolbachia strains infecting European butterflies, which until now was only inferred from mitochondrial diversity patterns. Our results show that horizontal and introgressive transfer of Wolbachia are frequent even between recently speciated host taxa, suggesting the symbiont's turnover rate is higher than had been inferred previously from surveys of distantly related hosts.

Animals↗
PubMed2005

Is evolution necessary for range expansion? Manipulating reproductive timing of a weedy annual transplanted beyond its range.

Ecologists often consider how environmental factors limit a species' geographic range. However, recent models suggest that geographic distribution also may be determined by a species' ability to adapt to novel environmental conditions. In this study, we empirically tested whether further evolution would be necessary for northern expansion of the weedy annual cocklebur (Xanthium strumarium) in its native North American range. We transplanted seedlings beyond the northern border and photoperiodically manipulated reproductive timing, a trait important for adaptation to shorter growing seasons at higher latitudes within the range, to determine whether further evolution of this trait would result in a phenotype viable beyond the range. Earlier reproductive induction enabled plants to produce mature seeds beyond the range and to achieve a reproductive output similar to those grown within the range. Therefore, evolution of earlier reproduction in marginal populations would be necessary for northward range expansion. This study is the first to empirically show that evolution in an ecologically important trait would enable a species to survive and reproduce beyond its current range. These results suggest that relatively few traits may limit a species' range and that identifying evolutionary constraints on such traits could be important for predicting geographic distribution.

Adaptation, Physiological↗
PubMed1984

Duration of the breeding season and response to reproductive manipulation in five breeds of sheep under northern prairie conditions.

The breeding season was 157, 154, <126, 210 and 217 days for Rambouillet, Columbia, Suffolk, Rambouillet x Finnish Landrace and Columbia x Finnish Landrace ewes respectively. Treatment of cyclic ewes with pregnant mare serum gonadotropin (PMSG) (500 IU), following a 12-day treatment with progestin-containing intravaginal sponges, did not affect fertility, but did decrease the time from sponge removal to estrus, (control 48.0 +/- 3.1 hr; PMSG 39.4 +/- 1.8 hr) to the preovulatory surge of LH (control 52.7 +/- 2.8 hr; PMSG 39.0 +/- 1.7 hr) and FSH (control 52.3 +/- 2.9 hr; PMSG 42.8 +/- 1.6 hr) and caused an elevation of serum LH levels prior to the preovulatory surge (control 1.25 +/- 0.18 ng/ml; PMSG 2.31 +/- 0.22 ng/ml). Exposure of the purebred ewes to 18 hours of daylight in January, decreasing by 30 minutes a week subsequently, counteracted the seasonal reduction in the number of ewes lambing following induced breeding under natural daylight in May. Prolificacy was greatest in crossbred ewes and their fertility was not affected by season. Gestation period was longer for fall-bred ewes and varied with breed.

Journal Article↗
PubMed2006

Fitness effects of Wolbachia and Spiroplasma in Drosophila melanogaster.

Maternally inherited endosymbionts that manipulate the reproduction of their insect host are very common. Aside from the reproductive manipulation they produce, the fitness of these symbionts depends in part on the direct impact they have on the female host. Although this parameter has commonly been investigated for single infections, it has much more rarely been established in dual infections. We here establish the direct effect of infection with two different symbionts exhibiting different reproductive manipulation phenotypes, both alone and in combination, in the fruit fly Drosophila melanogaster. This species carries a cytoplasmic incompatibility inducing Wolbachia and a male-killing Spiroplasma, occurring as single or double (co-) infections in natural populations. We assessed direct fitness effects of these bacteria on their host, by comparing larval competitiveness and adult fecundity of uninfected, Wolbachia, Spiroplasma and Wolbachia-Spiroplasma co-infected females. We found no effect of infection status on the fitness of females for both estimates, that is, no evidence of any benefits or costs to either single or co-infection. This leads to the conclusion that both bacteria probably have other sources of benefits to persist in D. melanogaster populations, either by means of their reproductive manipulations (fitness compensation from male death in Spiroplasma infection and cytoplasmic incompatibility in Wolbachia infection) or by positive fitness interactions on other fitness components.

Animals↗
PubMed2026

Wolbachia strain wLhui induces temperature-dependent incomplete cytoplasmic incompatibility in the invasive pest Liriomyza huidobrensis with biocontrol potential.

BACKGROUND: Wolbachia is a maternally inherited endosymbiont that manipulates host reproduction through cytoplasmic incompatibility (CI), offering promising opportunities for biocontrol of agricultural pests. The leaf-miner Liriomyza huidobrensis (Blanchard) is a globally invasive and highly polyphagous pest with a high incidence of Wolbachia infection; however, its reproductive effects remain poorly understood. Here, we investigated the reproductive manipulation induced by the Wolbachia strain wLhui using genomics analyses and crossing assays. RESULTS: wLhui localized primarily to the reproductive tissues of both female and male adults and maintained a 100% infection prevalence across three host generations under both low (15 and 20&#x2009;&#xb0;C) and moderate (25&#x2009;&#xb0;C) temperatures. Crossing assays showed that wLhui induced incomplete CI, reducing egg hatch by approximately 30% in incompatible crosses. Both CI strength (sh) and wLhui density varied with host rearing temperature. Genome sequencing revealed that wLhui (approximately 1.27&#x2009;Mb) belongs to supergroup A and harbors two pairs of CI factor genes (cifA and cifB). These Cif proteins are classified as Type I and exhibit substantial phylogenetic and structural divergence. Expression of CifB-pair1 caused growth defects in yeast, suggesting that CifB-pair1 exhibits toxicity. However, no direct interaction between CifA and CifB was detected by yeast two-hybrid assays. CONCLUSIONS: These findings elucidate the role and molecular basis of wLhui-induced reproductive manipulation and highlight its potential for developing Wolbachia-based biocontrol strategies against leaf-miner pests. &#xa9; 2026 Society of Chemical Industry.

Animals↗
PubMed1986

Effect of oxytocin, prostaglandin F2 alpha and reproductive tract manipulations on uterine contractility in Holstein cows on days 0 and 7 of the estrous cycle.

The influence of various treatments on cattle at the time of natural estrus vs estrus induced by prostaglandin F2 alpha (PGF2 alpha) or at d 7 of the estrous cycle were studied; the latter is when embryo transfer often is performed. Eight lactating and 25 nonlactating, normal cycling cows were tested many times while in estrus and 7 d after estrus. A balloon was positioned in the body of the uterus to record changes in intrauterine pressure following clitoral massage, cervical massage, vaginal distention, electrical stimulation of the cervix and vagina, tailhead rubbing, udder massage and the injection of oxytocin or PGF2 alpha. Blood oxytocin and intramammary pressure were measured. There were no differences between cows in estrus spontaneously or those induced, so these groups were combined. Intravenous oxytocin injections of .5, 1, 2, 4 and 15 IU increased blood levels of oxytocin. Intramammary pressure was increased by all oxytocin doses, but greater than or equal to 2 IU were required to cause substantial changes in uterine contractions. As expected, the peak contractions during control periods for cows in estrus were high, averaging 31 mm Hg vs 11 mm Hg on d 7. None of the manipulations of the reproductive organs caused detectable oxytocin release or increases in intramammary pressure, contrasting to responses to massage of the udder. Clitoral massage increased peak uterine pressure by 32 to 60% in four experiments. It did not induce luteinizing hormone release. The contraction was immediate, was not sustained and could be obtained repeatedly, suggesting a reflex response. Treatment with PGF2 alpha increased intramammary pressure. It increased uterine pressure on d 7, but had no effect at estrus. This contrasts with injected oxytocin, which resulted in the highest amplitude for cows in estrus, although the response on d 7 was greater in proportion to the low activity in controls at that time. It is concluded that manual manipulation of the reproductive tract (other than clitoral massage) has little effect on uterine contractility.

Animals↗
PubMed1991

Evaluation of reproductive traits in Bos taurus and Bos indicus crossbred heifers: effects of postweaning energy manipulation.

Reproductive traits were evaluated in Bos taurus and Bos indicus crossbred heifers that were fed different diets during the postweaning period. The study was designed in a 2 x 2 x 2 factorial arrangement of treatments. Angus x Hereford (AH; n = 148) and Brahman x Hereford (BH; n = 148) heifers were sorted after weaning by body weight into light (LW) and heavy (HW) weight blocks. Heifers in each weight block were assigned to diets calculated to reach a target weight of 55% (LE) or 65% (HE) of their projected mature weights by the start of the breeding season. Puberty was determined after a 160-d observation period and characterized by the following criteria: 1) behavioral estrus, 2) presence of a palpable corpus luteum (d 6 to 10; estrus = d 0), and 3) rise in serum progesterone above 1 ng/ml (d 6 to 10). A higher (P = .01) proportion of AH heifers than of BH heifers reached puberty by the breeding season (93% vs 67%). Interactions of breed x weight block and energy level x weight block also contributed to this difference. Weight at puberty was heavier (P = .001) among HE than among LE heifers and greater for heifers in HW than for those in LW blocks (P = .02). Differences in prebreeding weight, body condition, average daily gain, hip height, and pelvic area were influenced selectively by breed, energy level, or weight block. Pregnancy rates were higher (P = .01) among AH than among BH heifers. Incidence and severity of dystocia was influenced by the breed x energy level interaction (P = .01). Brahman x Hereford heifers had less (P = .01) dystocia than AH heifers, HE heifers had less (P less than .02) dystocia than LE heifers, and HE-AH heifers had less (P less than .01) dystocia than LE-AH contemporaries. Subsequent duration of the postpartum interval to estrus was shorter (P = .002) among AH than among BH females. Pregnancy rates at the end of the 2nd yr were higher (P = .02) among LW than among HW females and weights were heavier (P = .001) at weaning among calves weaned from BH dams.

Animal Feed↗
PubMed2006

WO bacteriophage transcription in Wolbachia-infected Culex pipiens.

Bacteriophages are commonly found in association with free-living bacteria, both as exogenic phages (virions) and as prophages integrated into the bacterial genome. In contrast, the observation of bacteriophages associated with obligate intracellular bacteria has been described infrequently. An exception is provided by Wolbachia endosymbionts, which harbor multiple phage elements that have been designated as WO phage. Wolbachia are maternally inherited bacteria that occur in the cytoplasm of many invertebrates, where they often manipulate host reproduction. Previously, the WO phage orf7 locus and ankyrin repeat-encoding genes have been observed to represent sources of genetic diversity between Wolbachia (wPip) strains infecting mosquitoes of the Culex pipiens complex and have been suggested as potential participants in the reproductive manipulations. We have characterized WO phage associated with multiple Wolbachia-infected Culex strains and an uninfected strain using electron microscopy and RT-PCR. For each strain, different developmental stages were examined for transcription of three WO phage orf7 genes. The results provide evidence for the presence of both actively transcribed virions and inactive prophages. Variable orf7 transcription patterns are observed in comparisons of differing Cx. pipiens strains. Variability includes both mosquito stage-specific and sexually dimorphic orf7 expression patterns. This report provides additional support for the hypothesis that bacteriophages play an important role in Wolbachia and host evolution.

Animals↗
PubMed2001

Optimal allocation of reproductive effort: manipulation of offspring number and size in the bank vole.

The number of offspring attaining reproductive age is an important measure of an individual's fitness. However, reproductive success is generally constrained by a trade-off between offspring number and quality. We conducted a factorial experiment in order to study the effects of an artificial enlargement of offspring number and size on the reproductive success of female bank voles (Clethrionomys glareolus). We also studied the effects of the manipulations on growth, survival and reproductive success of the offspring. Potentially confounding effects of varying maternal quality were avoided by cross-fostering. Our results showed that the number of offspring alive in the next breeding season was higher in offspring number manipulation groups, despite their smaller body size at weaning. Offspring size manipulation had no effect on offspring growth or survival. Further, the first litter size of female offspring did not differ between treatments. In conclusion, females may be able to increase the number of offspring reaching reproductive age by producing larger litters, whereas increasing offspring size benefits neither the mother nor the offspring.

Animals↗
PubMed2003

A bacterial symbiont in the Bacteroidetes induces cytoplasmic incompatibility in the parasitoid wasp Encarsia pergandiella.

Vertically transmitted symbionts of arthropods have been implicated in several reproductive manipulations of their hosts. These include cytoplasmic incompatibility (CI), parthenogenesis induction in haplodiploid species (PI), feminization and male killing. One symbiont lineage in the alpha-Proteobacteria, Wolbachia, is the only bacterium known to cause all of these effects, and has been thought to be unique in causing CI, in which the fecundity of uninfected females is reduced after mating with infected males. Here, we provide evidence that an undescribed symbiont in the Bacteroidetes group causes CI in a sexual population of the parasitic wasp Encarsia pergandiella. Wasps were crossed in all four possible combinations of infected and uninfected individuals. In the cross predicted to be incompatible, infected (I) males x uninfected (U) females, progeny production was severely reduced, with these females producing only 12.6% of the number of progeny in other crosses. The incompatibility observed in this haplodiploid species was the female mortality type; dissections showed that most progeny from the incompatible cross died as eggs. The 16S rDNA sequence of this symbiont is 99% identical to a parthenogenesis-inducing symbiont in other Encarsia, and 96% identical to a feminizing symbiont in haplodiploid Brevipalpus mites. Thus, this recently discovered symbiont lineage is capable of inducing three of the four principal manipulations of host reproduction known to be caused by Wolbachia.

Animals↗
PubMed2001

Regulation of ovarian follicular dynamics in farm animals. Implications for manipulation of reproduction.

In this review, the main features of folliculogenesis are summarized and compared among species. In the past few years, ultrasonography has clarified follicle growth patterns, and our understanding of follicle maturation has improved considerably. As the follicles develop towards the ovulatory stage, three features appear to be highly conserved across all species: 1) the sequence of events (recruitment, selection and dominance); 2) the sequential need for gonadotropins (FSH for recruitment, LH for dominance) and 3) the large variability of numerical parameters (number of waves per cycle, number of follicles per wave) as well as temporal requirements (time of selection, duration of dominance). In addition, specific follicles may also have variable gonadotropin requirements (thresholds). When patterns of follicle development at different physiological states are compared across species, follicular waves were detected in cattle, sheep and horses and during the prepubertal period in swine, suggesting that ovaries of all species operate on a wave basis unless they are prevented from doing so. Efficient estrus control treatments should have the ability to affect 1) the wave pattern by preventing the development of persistent dominant follicles containing aging oocytes, and 2) the recruitment of the future ovulatory follicle whatever the stage of the wave at the time of treatment. This would allow synchronous ovulation of a growing dominant follicle. Manipulation of the luteal phase follicular waves after mating or AI may also optimize fertility. Superovulation is still an efficient technique to obtain progeny from genetically valuable females. Administration of exogenous gonadotropins acts to reveal the underlying ovarian variability. Ovarian response of each female depends on the number of gonado-sensitive follicles present at the time when treatment is initiated. Identification of the number of such follicles for each female would improve efficacy of superovulation, by allocating potential nonresponders to other techniques (OPU/FIV). One of the main components of the within female response to superovulation is the stage of the wave when gonadotropins are injected. Treatment in the absence of a dominant follicle ensures a response close to the female's specific maximum. The development of practical approaches to achieve this still requires further research.

Animals↗
PubMed1990

Reproductive anatomy, manipulation of ovarian activity and non-surgical embryo recovery in suni (Neotragus moschatus zuluensis).

Marked disparity in the uterine horn dimensions and relative degrees of caruncle development in suni suggested that exclusive or predominant dextral implantation occurs in association with bilateral ovulatory activity. Daily urinary measurements of pregnanediol-3 alpha-glucuronide revealed an oestrous cycle of approximately 21 days in length. Ovarian activity was controlled for synchronization of oestrus by using progestagen-impregnated intravaginal sponges and multiple ovulations were induced by using exogenous gonadotrophin therapy. An effective transcervical uterine catheterization technique was developed for the non-surgical collection of embryos. The efficiency of embryo recovery performed 5 days after sponge removal was 50.0%.

Animals↗
PubMed2004

[Delay and cessation of aging processes by manipulation of reproduction, food intake and development in insects].

Insects can serve as excellent models to show that the genetically determined life span of organisms as well as that of other traits is characterized by high phenotypic plasticity. Depending on different environmental conditions the life cycle strategy can therefore be highly variable. Thus developmental and aging processes are subjected to delaying or accelerating influences or can even be interrupted. Availability of protein to fulfill reproductive requirements, intermittent starvation, and the photoperiodic induction of reproductive diapause were taken as examples for the study of selected abiotic factors which influence the life history of the blowfly Phormia terraenovae and the beetle Gastroidea viridula.

Adaptation, Physiological↗
PubMed1992

Manipulation of reproduction in sheep.

Active immunization of cyclic ewes against androstenedione (using melatonin, Fecundin) has been shown to increase reproductive output by about 30 extra lambs per 100 ewes put to the ram in UK sheep flocks. However, this technique has not been widely adopted within the industry. One possible reason for this is that it results in an unacceptable incidence of triplet births, even though the litter size distribution is similar to that obtained for untreated flocks with the same overall mean lambing percentage. The use of progestagen sponges plus pregnant mares' serum gonadotrophin (PMSG) for the induction of out-of-season breeding in ewes is associated with a number of recognized shortcomings. A possible reason for the variability in conception rates is the high incidence of complete embryo loss or fertilization failure in ewes that are induced to superovulate after treatment with the doses of PMSG required to promote a high oestrous response. Recent studies have indicated that slow release implants of melatonin (Regulin) can advance the onset of the breeding season of commercial sheep flocks, but only by about 4 weeks. This means that the optimum treatment window varies according to the natural breeding season characteristics for the breed. Nevertheless, this treatment appears to overcome a number of the shortcomings of progestagen sponges plus PMSG. It also produces a modest increase in litter size per ewe pregnant (about 15 extra lambs per 100 ewes) without the wide variation in birth types and birth weights associated with PMSG. The development of a laparoscopic procedure that improves conception rates after intrauterine insemination of frozen semen allows comparisons of genetic merit across flocks. This should promote far greater rates of genetic improvement for traits of high economic importance than those achieved by within-flock selection and in the last two years has allowed the development of sire-referencing schemes within the major terminal sire breeds. Laparoscopic procedures for the collection and transfer of embryos in sheep now have the potential to overcome many of the limitations of more invasive surgical approaches, although the unpredictability of superovulatory responses remains a particular obstacle to full exploitation of multiple ovulation embryo transfer (MOET) for genetic improvement through the female line.

Animals↗