Spermatozoa were the first cell type in which the cellular generation of reactive oxygen was demonstrated. This activity has now been confirmed in spermatozoa from all mammalian species examined including the rat, mouse, rabbit, horse, bull and human being. Under physiological circumstances, cellular redox activity is thought to drive the cAMP-mediated, tyrosine phosphorylation events associated with sperm capacitation. In addition to this biological role, human spermatozoa also appear to suffer from oxidative stress, with impacts on the normality of their function and the integrity of their nuclear and mitochondrial DNA. Recent studies have helped to clarify the molecular basis for the intense redox activity observed in defective human spermatozoa, the nature of the subcellular structures responsible for this activity and possible mechanisms by which oxidative stress impacts on these cells. Given the importance of oxidative damage in the male germ line to the origins of male infertility, early pregnancy loss and childhood disease, this area of sperm biochemistry deserves attention from all those interested in improved methods for the diagnosis, management and prevention of male-mediated reproductive failure.
Knowledge of reproductive biology is crucial to improving in situ and ex situ breeding programmes for felids. We reviewed the available literature (223 publications) on the reproductive biology of all 38 felid species. We found that 78% of the publications (173) were focused on either or both the oestrous cycles (84) or ejaculate traits (92) of felids. Literature was biased towards the domestic cat Felis catus (31), the cheetah Acinonyx jubatus (27), and the panthera lineage (66). There was a paucity of literature on the caracal lineage (7), the bay cat lineage (3), members of the domestic cat lineage other than the domestic cat (11), and several species of the ocelot lineage. The mean duration of oestrus varies little between the different lineages and species (mean 5.2 days, range 1–10 days, n E = 2265). However, the duration of interoestrus varies greatly in most species (e.g. 1–118 days in the domestic cat). Gestation length also varies significantly between species, but is similar within each lineage and related to adult body size. Non‐pregnant luteal phases appear to persist for half the duration of pregnant luteal phases (48%, 21–71 days, n E = 256; c.f. previous reports of one‐third the duration of pregnant luteal phases). Sperm motility (sperm motility index), sperm viability, and acrosome intactness are high in the fresh ejaculates of most felid species [69% (26–90%, n E = 2104), 69% (49–87%, n E = 443), and 84% (21–100%, n E = 1763), respectively]. Teratospermia is highly prevalent within Felidae, but is particularly problematic for the puma and lynx lineages [ejaculates with 76% (63–94%) and 79% (63–98%) abnormal sperm, respectively]. Teratospermia appears to be linked to low genetic diversity. The maintenance and enhancement of genetic diversity through the use of assisted reproductive technologies should be a long‐term goal for felid conservation management. A short‐term management goal should be to improve the success of assisted reproductive technologies in felids by minimising captivity‐related stress, which can adversely affect fertility and ovarian activity.
Different aspects of reproductive biology of S. plagiostomus were studied in this work from February 2014 to January 2015. Fishes were collected from Sheringal valley right from Kumrat thal valley to Chukyatan Dir Upper. Fecundity and Gonado-somatic index was studied using gravimetric to infer about breeding season and reproductive potential. The mean value of absolute fecundity recorded was 14670.39 while mean value of relative fecundity was noted as 34.78. The mean value recorded for conditioned factor was 0.912 g/cm(3). Relationship of fecundity with body length, body weight, ovary weight and the interrelationship of body length and body weight was established statistically using Linear Regression. The values of determination coefficient (R-2) at P 0.05). The study provides basic information about the reproductive potential and behavior of S. plagiostomus which will be handy towards its culture.
Studies on reproduction of the dragonfishes, Bathydraconidae, are scarce, and within this family, the reproductive biology of Parachaenichthys charcoti was poorly understood. Herein we present a histologic analysis of P. charcoti ovaries together with data on reproductive effort using fish collected with trammel nets in austral summer at Potter Cove, South Shetland Islands (SSI), and compare this information with that reported for the South Georgia congener Parachaenichthys georgianus. In gravid females of P. charcoti, GSI of 16–31%, mature oocytes of 1.8–3.9 mm and total fecundity (TF) of 9025–18,937 oocytes/individual (X ± SD = 12,617 ± 4019, n = 7) were recorded. The histology of the ovaries confirmed the common characteristics of the Notothenioidei observed macroscopically, i.e., two distinct batches of oocytes, one in the previtellogenic stage (primary growing or cortical alveoli stages) and the other in vitellogenesis and likely to be released in the current season. A longer incubation period of P. charcoti compared with P. georgianus is associated to the colder waters at the SSI. Based on our sampling and reproductive effort data, together with the reported nesting behavior for P. charcoti, it is assumed that this species spawns in nearshore, sheltered waters in summer, presumably from late December to February. Spawning periods of both congeners differ from those reported for other notothenioids in the same Seasonal Pack-ice Zone, suggesting divergence in some aspects of the life strategies in the genus Parachaenichthys. Likewise, although there are no substantial differences between P. charcoti and other notothenioids regarding gonadal development, the genus Parachaenichthys shows distinct features in its reproductive strategies (e.g., higher TF) compared with other bathydraconid species.
The 2018 edition of the Society for Reproductive Biology's (SRB) Annual Meeting was a celebration of 50 years of Australian research into reproductive biology. The past 50 years has seen many important contributions to this field, and these advances have led to changes in practice and policy, improvements in the efficiency of animal reproduction and improved health outcomes. This conference review delivers a dedicated summary of the symposia, discussing emerging concepts, raising new questions and proposing directions forward. Notably, the symposia discussed in this review emphasised the impact that reproductive research can have on quality of life and the health trajectories of individuals. The breadth of the research discussed encompasses the central regulation of fertility and cyclicity, life course health and how the environment of gametes and embryos can affect subsequent generations, significant advances in our understanding of placental biology and pregnancy disorders and the implications of assisted reproductive technologies on population health. The importance of a reliable food supply and protection of endangered species is also discussed. The research covered at SRB's 2018 meeting not only recognised the important contributions of its members over the past 50 years, but also highlighted key findings and avenues for innovation moving forward that will enable the SRB to continue making significant contributions for the next 50 years.
The seasonal developmental rhythm, floral and fruit morphology, anthesis, and fructification of Asarum sieboldii were studied in a natural plant community in the southern part of the Russian Far East. The flower structure was investigated in ditails. It was found that the flower does not have a gynostemium. The flowers are protogynous. At the first anthesis stage, the anthers are closed and cross-pollination may be realized by ants (Hymenoptera) or flies (Dolichopodidae, Diptera). At the second stage of anthesis, there is direct contact of anthers with the pistil stigma and self-pollination occurs. The perianth is involved in the formation of fruit. The fruit is a six-locular, fleshy, half-inferior capsule. Asarum sieboldii has a high productivity of fruits and seeds. The fruit set is 89% after self-pollination. Viable seeds per fruit is 29 ± 2, the seed set is 69 ± 5%. The agents of seed dissemination are ants: Leptothorax acervorum and Myrmica ruginodis (Formicidae, Hymenoptera).
Sexually mature adults and embryos and larvae of C ephalodiscus nigrescens and C . gracilis were studied by light and electron microscopy. Contrary to claims in the literature, individual coenecial cavities are inhabited by colonies of up to 15 joined zooids and not by single individuals, which is important for the interpretation of the mode of life of the related fossil group the graptolites. Some aspects of the reproductive apparatus and reproduction in C ephalodiscus are reported. The ultrastructure of the spermatozoon is described for the first time. Coelom formation is by schizocoely. The structure of the larva at several developmental stages is illustrated. Not all fertilised eggs are destined to become motile larvae and some develop into zooids omitting the motile stage. The lumen of the oviduct is much larger than previously supposed. Spermatozoa are shed into the cavity of the coenecium. It is proposed that fertilisation takes place within the coenecium. The ultrastructure of the enigmatic black ‘ C omma B ody’ is described and a reproductive function is proposed. Budding takes place from a base common to several zooids. This base probably also serves as an attachment foot. Large masses of yolk have been discovered within the coelom of some zooids and muscle stalks. It is inconceivable that a colony of C ephalodiscus nigrescens could survive unless it spent most of its life outside the coenecium.
Reproductive strategies such as parental care have been pivotal in evolutionary innovations such as endothermy in birds and mammals. The diversity of reproductive biology across the squamates provides a unique opportunity for elucidating the selective forces responsible for the evolution of various reproductive strategies. Here, I report on the reproductive biology of the southern African python ( Python natalensis ), based on a 7‐year study of free‐ranging pythons, revealing a behavioural complexity not usually expected for snakes. Mating occurred in the austral winter, with individual males following females for more than 2 months. As is typical for pythons, females brooded eggs by coiling around the clutch. Females are capital breeders; they lost ~40% body mass during a breeding event and did not breed in consecutive years. There was no evidence of the facultative thermogenesis that has been reported in congeners, suggesting that facultative thermogenesis has arisen independently more than once in Python . Reproductive females thermoregulated more carefully than non‐reproductives, maintaining higher, more stable T b s at all stages of reproduction, especially while brooding. This was achieved by a stereotypic basking regime facilitated by ‘facultative melanism’, with females darkening significantly for the entire breeding event. Mothers remained with neonates at the nest site for approximately 2 weeks after hatching. During this time, mothers alternated between brief bouts of basking on the surface and coiling around the hatched eggs, on which the neonates rested. Neonates formed an aggregation near the burrow entrance to bask during the day, individually returning to the nest intermittently throughout the day. During the night, neonates remained within the mother's coils on the hatched eggs. This study highlights the diversity of reproductive biology within Python and cautions against generalization in this regard. This is the first unambiguous report of maternal care of neonates in an oviparous snake. The diversity of reproductive biology across the squamates provides a unique opportunity for elucidating the selective forces responsible for the evolution of various reproductive strategies. Here, I report on the reproductive biology of the southern African python ( Python natalensis ), based on a 7‐year study of free‐ranging pythons, revealing a behavioural complexity not usually expected for snakes. Furthermore, this is the first unambiguous report of maternal care of neonates in an oviparous snake.
Ascidians are abundant and well-represented members of worldwide benthic communities, including Antarctica and the Arctic. These organisms exhibit different reproductive patterns usually related to a latitudinal gradient, as do many marine invertebrate species. Reproductive seasonality varies from one or two annual peaks in cold and temperate water species to continuous reproduction throughout the year in warm water species. Styela rustica (Linnaeus 1767) and Halocynthia pyriformis (Rathke 1806) are solitary species with external fertilization and a wide distribution range, from the North Atlantic to the Arctic. The reproductive patterns of these two species were assessed for Arctic populations by year-round sampling and structural analysis of the gonads. Both species are hermaphrodites and showed marked seasonality in oocyte maturity and spawning; S. rustica peaked during the boreal summer and H. pyriformis in late spring. The two species also showed marked differences in mature oocyte sizes: H. pyriformis almost doubled those of S. rustica and, while spermatocytes of H. pyriformis were mature year-round, the maturity of male and female gametes was synchronized in S. rustica. The species thus showed an annual reproductive cycle coupled with a higher production period in the ecosystem, but also exhibited different strategies developed under the same environmental pressures.
Southern hairy-nosed wombats (SHNWs: Lasiorhinus latifrons) do not breed well in captivity. To better understand their reproduction, daily urine samples were collected from nine captive females and analysed for volume (mL), specific gravity and a qualitative index of the number of epithelial cells, then stored at -20 degrees C until samples could be analysed for progesterone metabolites (P4M). The mean oestrous cycle length was 35.1 +/- 2.4 days; however, individual cycle length ranged from 23 to 47 days. The mean luteal phase length was 20.8 +/- 1.3 days (range: 12 to 33 days). Urinary P4M was divided into four oestrous cycle stages: (1) early follicular phase, (2) late follicular phase, (3) early luteal phase, (4) late luteal phase, and analysed against urinary characteristics. During the late follicular phase, urine volume decreased (P = 0.002) while urine specific gravity (P = 0.001) and concentration of epithelial cells (P = 0.004) both increased. The level of variability in oestrous cycle length suggests that some captive females may exhibit abnormal cycles; however, the changes in the urinary characteristics associated with the different stages of the oestrous cycle appear to offer a possible non-invasive means of monitoring the reproductive status of captive SHNWs.