Effect of the cumulus on in vitro fertilization of bovine matured oocytes

The effect of the cumulus on in vitro fertilization in bovines was examined. Follicular oocytes were cultured in medium 199 plus OCS and extra granulosa cells. Frozen-thawed bovine spermatozoa was separated by the swim-up technique, suspended in Talp medium and capacitated with heparin. Fresh sheep and goat semen was incubated for 4 h at room temperature, washed and spermatozoa were then suspended in Talp medium and capacitated by incubation at 38.5 °C and 5% CO₂ in air and heparin.

In experiment 1, cumulus-enclosed oocytes, denuded oocytes and denuded oocytes plus additional cumulus cells were incubated with a reduced concentration of bovine spermatozoa for 8 or 18 h. In Experiment 2, cumulus enclosed and denuded oocytes were incubated with bovine spermatozoa for 4, 6, 8 and 18 h using a sperm concentration adjusted to secure high fertilization rates. In Experiment 3, cumulus-enclosed and denuded bovine oocytes were incubated with either sheep or goat spermatozoa for 18 h. Fertilization rates were then calculated and compared statistically. The results showed that 1) the cumulus improved the fertilization rate only when cumulus cells were associated with the oocytes 2) the timing of sperm penetration was not modified by the cumulus and started at 4 h after sperm incubation and 3) the presence of the cumulus improved the heterologous fertilization rate only when sheep spermatozoa were used. The results suggest that the cumulus improves fertilization rate by providing a capacitation-inducing mechanism and by facilitating the interaction between capacitated spermatozoa and the zona pellucida surface.     

Social group composition modulates the role of last male sperm precedence in post-copulatory sexual selection

In many species, the order in which males mate with a female explains much of the variation in paternity arising from post-copulatory sexual selection. Research in Drosophila suggests that mating order may account for the majority of the variance in male reproductive success. However, the effects of mating order on paternity bias might not be static but could potentially vary with social or environmental factors. To test this idea, we used an existing dataset, collated from an experiment we previously published (Morimoto et al., PLoS One, 11, 2016, e0154468), with the addition of unpublished data from the same experiment. These previous experiments manipulated larval density in Drosophila melanogaster which generated variation in male and female body size, assembled groups of individuals of different sizes, and measured the mating success and paternity share of focal males. The data presented here provides information on each focal male's mating order and the frequency in which focal males remated with same females (‘repetitive matings’). We combined this information with our previously reported focal male reproductive success to partition variance in paternity into male mating order and repetitive matings across groups that differed in the body size composition of males and females. We found, as expected, that male mating order explained a considerable portion of the variance in male paternity. However, we also found that the impact of male mating order on male paternity was influenced by the body size composition of groups. Specifically, males that tended to mate last had a greater paternity advantage, and displayed lower variance, in groups containing a heterogenous mixture male body sizes than in groups with a single male body size. Repetitive mating only had a minor contribution to the variance in male paternity share across all experiments. Overall, our findings contribute to the growing body of research showing that post-copulatory sexual selection is subject to socio-ecological influences.     

Proper phosphorylation of septin 12 regulates septin 4 and soluble adenylyl cyclase expression to induce sperm capacitation

Septin-based ring complexes maintain the sperm annulus. Defective annular structures are observed in the sperm of Sept12- and Sept4-null mice. In addition, sperm capacitation, a process required for proper fertilization, is inhibited in Sept4-null mice, implying that the sperm annulus might play a role in controlling sperm capacitation. Hence, we analyzed sperm capacitation of sperm obtained from SEPT12 Ser196 phosphomimetic (S196E), phosphorylation-deficient (S196A), and SEPT4-depleted mutant mice. Capacitation was reduced in the sperm of both the Sept12 S196E- and Sept12 S196A-knock-in mice. The protein levels of septins, namely, SEPT4 and SEPT12, were upregulated, and these proteins were concentrated in the sperm annulus during capacitation. Importantly, the expression of soluble adenylyl cyclase (sAC), a key enzyme that initiates capacitation, was upregulated, and sAC was recruited to the sperm annulus following capacitation stimulation. We further found that SEPT12, SEPT4, and sAC formed a complex and colocalized to the sperm annulus. Additionally, sAC expression was reduced and disappeared in the annulus of the SEPT12 S196E- and S196A-mutant mouse sperm. In the sperm of the SEPT4-knockout mice, sAC did not localize to the annulus. Thus, our data demonstrate that SEPT12 phosphorylation status and SEPT4 activity jointly regulate sAC protein levels and annular localization to induce sperm capacitation.     

Reproductive status of cheetahs (Acinonyx jubatus) in North American Zoos: The benefits of physiological surveys for strategic planning

Under the mandate of a Species Survival Plan (SSP), reproductive status was assessed in 128 cheetahs maintained in 18 different institutions in North America. A mobile laboratory research team evaluated cheetahs using anesthesia, serial blood sampling, electroejaculation (males), and laparoscopy (females). Biomaterials were also collected for parallel studies of genetics, nutrition, and health. There was no mortality, and cheetahs were capable of reproducing naturally after these intense manipulatory examinations. No marked differences were observed in reproductive or endocrine characteristics between proven and unproven breeders. However, males consistently produced teratospermic ejaculates, and cheetah sperm were compromised in conspecific or heterologous in vitro fertilization systems. Structurally abnormal sperm were found to be filtered by the oocyte's zona pellucida. More than 80% of the females were anatomically sound, but morphological and endocrine evidence suggested that ～50% or more of the population may have had inactive ovaries at the time of the examination. Males ranging in age from 15 to 182 months produced spermic ejaculates, but motile sperm numbers/ejaculate and circulating testosterone concentrations were highest in males 60 to 120 months old. Parovarian cysts were observed in 51.5% of female cheetahs, but comparisons between proven and unproven subpopulations revealed that this abnormality likely had no influence on fertility. Fresh luteal tissue was not observed in any nonpregnant or nonlactating female, strongly suggesting that the cheetah is an induced ovulator. Overall survey results were discussed in the context of the etiology of reproductive inefficiency, especially with respect to the potential importance of biological versus management factors. Four high priority research areas in cheetah reproductive biology were identified: 1) continuous monitoring of ejaculate quality in the extant population, while studying the impact of pleiomorphisms on fertility; 2) determining the potential relationship between libido and androgen production (excretion) in males; 3) confirming the extent of cyclic, or acyclic, ovarian activity in females; and 4) continued development of assisted reproductive techniques for enhancing man-agement. In summary, a multidisciplinary, multi-institutional survey coordinated through the SSP is both possible and useful for generating a physiological and health database beneficial to driving further research and management initiatives. © 1993 Wiley-Liss, Inc.     

Noninvasive semen collection from an adult orangutan

Preservation of the genetic diversity of the captive orangutan, especially the wild-caught founders, is critical in maintaining a long-term population in zoological parks. One solution to the problem of maintaining maximum genetic diversity would be to initiate a program of artificial insemination for genetically underrepresented individuals through the banking and interinstitutional use of cryopreserved semen. However, little is known about basic orangutan semen characteristics, and current methodology is inadequate to support such a program. In this paper, we report the results of semen collection from an adult Sumatran orangutan (Pongo pygmaeus abelli), using an artificial vagina without anesthesia or electrical stimulation. A total of 27 ejaculates were evaluated during a 1-year period. The total and liquid volumes of the ejaculates at 1 h following collection were 6.1 ± 0.6 ml and 2.6 ± 0.4 ml, respectively (mean ± SEM). The liquid portion continued to exude semen for 2 h; however, 90% of the motile sperm was exuded within the first 30 min. The total number of sperm in the ejaculate was 164 ± 10⁶ ± 16.5, and the percentage of motile cells was 60 ± 2.7%. We conclude that the artificial vagina provides a promising technique for semen collection in the orangutan, and view these results as an initial step in developing methods for in vitro sperm capacitation, sperm cryopreservation, and artificial insemination. © 1993 Wiley-Liss, Inc.     

Mating tactics in external fertilizers when sperm is limited

Among externally fertilizing animals in aquatic habitats, theproportion of a female's egg clutch that is successfully fertilizedoften falls below 100%. In many such species, particularly incoral reef fishes, males spawn daily at high frequencies, oftenwith little or no sperm competition. A major evolutionary problemfor such males is how best to allocate sperm over successivespawns. Females face the problem of ensuring complete fertilizationof their egg clutch. Here we model male and female mating tacticswhen daily sperm production is limited and with various assumptionsconcerning how differences in the number of sperm released duringa mating influence the number of eggs fertilized. The modelsreveal conditions under which males can maximize daily reproductivesuccess, either by releasing a fixed number of sperm duringall successive spawns or by matching sperm numbers to the clutchsize of their mates. These patterns of sperm allocation exertdifferent pressures on females, which may respond evolutionarilyby developing various mating tactics of their own.     

Light and electron microscopic studies on the seminal secretions and the vas deferens of the penaeiodean shrimp,Sicyonia ingentis

Unlike the other penaeiodean shrimp, the ridge back shrimp, Sicyoniaingentis does not produce a spermatophore, but transfers sperm suspended in seminal plasm. This paper reports on the histomorphology and ultrastructure of the vas deferens with reference to its functional role in secreting the sperm bearing materials. The vas deferens is divisible into proximal secretory, mid storage and distal ejaculatory regions. The epithelial cells lining the proximal vas deferens are comprised of secretory and absorptive cell types. The loose sperm cells found in the lumen of this region are in an immature condition, and are agglutinated into a compact mass with signs of spermiogenesis in the mid vas deferens. The epithelial cells lining the mid vas deferens are short flattened cells. The distal vas deferens is ensheathed by muscular fibres. The inner epithelial cells are highly secretory and contain numerous microvilli at the luminal end. The sperm cord gets liquefied in this region facilitating the transfer of sperm in liquid form to the female during mating.     

AN ASSESSMENT OF CHANGES WITH TIME IN THE MARKING PATTERNS USED FOR PHOTOIDENTIFICATION OF INDIVIDUAL SPERM WHALES, PHYSETER MACROCEPHALUS

We observed changes with time in the patterns of characteristic fluke markings used to identify sperm whales. Changes were categorized as minor, moderate, or major based on their severity. These change types were found to occur at rates of 0.9%, 11.8%, and 1.3% per individual per year, respectively. Gain and loss rates for each of seven different mark types were also calculated. The highest estimated rate was the gain of small nicks at 0.08 per individual per year. Most individuals identified by us possess at least a few characteristic marks and, therefore, changes of the type observed in this study are unlikely to severely affect their recognizability. For all but one mark type, gain rates were higher than loss rates, indicating that individuals may be accumulating marks with age. Over long periods this could eventually make individuals unrecognizable, with the result that population sizes calculated from these data may be overestimated. As long as photoidentification studies are conducted sufficiently often, and these changes are as gradual as they appear to be, this problem should be minimal.     

The SEA module: a new extracellular domain associated with O-glycosylation.

Using a variety of homology search methods and multiple alignments, a new extracellular module was identified in (1) agrin, (2) enterokinase, (3) a 63-kDa sea urchin sperm protein, (4) perlecan, (5) the breast cancer marker MUCI (episialin), (6) the cell surface antigen 114/A10, and (7/8) two functionally uncharacterized, probably extracellular, Caenorhabditis elegans proteins. Despite the functional diversity of these adhesive proteins, a common denominator seems to be their existence in heavily glycosylated environments. In addition, the better characterized proteins mentioned above contain all O-glycosidic-linked carbohydrates such as heparan sulfate that contribute considerably to their molecular masses. The common module might regulate or assist binding to neighboring carbohydrate moieties.     

Multiple paternity in the red-eyed treefrog Agalychnis callidryas (Cope)

DNA fingerprinting of tadpoles from two different ‘one female-two male’ matings of the red-eyed treefrog, Agalychnis callidryas, revealed multiple paternity of offspring. Offspring were assigned paternity based on bands shared with the putative father, but not shared between putative fathers or with the mother. Paternity was split 44/56% and 36/64% in two matings. These results do not support a hypothesis of sperm priority in access to unfertilized eggs by primary males. Multiple paternity may be commonplace in species of anurans with matings by multiple males.