Role of water percolation in reproductive physiology of hazelnut (Corylus spp.)

2021 ◽  
Vol 182 ◽  
pp. 104278
Author(s):  
Murali-Mohan Ayyanath ◽  
Mukund R. Shukla ◽  
Praveen K. Saxena
Keyword(s):  
Reproductive Physiology ◽  
Water Percolation

Embryo biotechnology in the dog: a review

2010 ◽  
Vol 22 (7) ◽  
pp. 1049 ◽  
Author(s):  
Sylvie Chastant-Maillard ◽  
Martine Chebrout ◽  
Sandra Thoumire ◽  
Marie Saint-Dizier ◽  
Marc Chodkiewicz ◽  
...  
Keyword(s):  
Mammalian Species ◽  
Embryonic Stem ◽  
Reproductive Technologies ◽  
Reproductive Physiology ◽  
Biological Models ◽  
The Past ◽  
Fertilisation Rate

Canine embryos are a scarce biological material because of difficulties in collecting in vivo-produced embryos and the inability, to date, to produce canine embryos in vitro. The procedure for the transfer of in vivo-produced embryos has not been developed adequately, with only six attempts reported in the literature that have resulted in the birth of 45 puppies. In vitro, the fertilisation rate is particularly low (∼10%) and the incidence of polyspermy particularly high. So far, no puppy has been obtained from an in vitro-produced embryo. In contrast, cloning of somatic cells has been used successfully over the past 4 years, with the birth of 41 puppies reported in the literature, a yield that is comparable to that for other mammalian species. Over the same period, canine embryonic stem sells and transgenic cloned dogs have been obtained. Thus, the latest reproductive technologies are further advanced than in vitro embryo production. The lack of fundamental studies on the specific features of reproductive physiology and developmental biology in the canine is regrettable in view of the increasing role of dogs in our society and of the current demand for new biological models in biomedical technology.

Effects of photoperiod on the reproductive physiology of male flying foxes, Pteropus poliocephalus

1992 ◽  
Vol 4 (1) ◽  
pp. 43 ◽  
Author(s):  
MA McGuckin ◽  
AW Blackshaw
Keyword(s):  
Reproductive Physiology ◽  
Adult Males ◽  
Progressive Decrease ◽  
Natural Conditions ◽  
Timing Of Reproduction ◽  
Pteropus Poliocephalus ◽  
Natural Photoperiod ◽  
Short Days ◽  
Photoperiod Manipulation

Melatonion concentrations were determined in plasma pools obtained from adult male Pteropus poliocephalus (autumn mating season) at four times of the year. Melatonin levels increased within 3 h of sunset and remained elevated for the duration of the scotophase at all times of the year. Two photoperiod manipulation experiments were performed to examine the role of daylength in the regulation of the timing of the breeding season of this species. In Experiment 1, three adult males were transferred from natural short days to 16L:8D for 137 days and then photoperiod was progressively decreased over 120 days to 9L:15D; this photoperiod was then maintained for 350 days. Testicular volume (TV) peaked during decreasing photoperiod well before the time of maximal size in natural conditions. During the period in extended short photoperiod these bats showed several cycles of TV change with a progressively decreasing interval between cycles. In Experiment 2, nine adult males were exposed to the same shift to 16L:8D as in Experiment 1, but were subsequently split into three groups: 8L:16D, progressive decrease to 8L:16D and maintenance in 16L:8D. The 8L:16D and decreasing photoperiod groups showed coincident premature increases in TV, as in Experiment 1, whereas in the 16L:8D group TV increased at about the same time as in animals in natural photoperiod. Melatonin determination in the different experimental groups showed that duration of secretion was related to the length of the scotophase in all cases. These experiments demonstrate that regulation of the timing of reproduction in males of this species is influenced by changes in daylength.

ROLE OF POLYAMINES IN REPRODUCTIVE PHYSIOLOGY AND SEX HORMONE ACTION

1970 ◽  
Vol 171 (3 Metabolism an) ◽  
pp. 882-894 ◽  
Author(s):  
H. G. Williams-Ashman ◽  
D. H. Lockwood
Keyword(s):  
Sex Hormone ◽  
Reproductive Physiology ◽  
Hormone Action

Role of the teneurins, teneurin C-terminal associated peptides (TCAP) in reproduction: clinical perspectives

2015 ◽  
Vol 24 (2) ◽  
Author(s):  
David A. Lovejoy ◽  
Téa Pavlović
Keyword(s):  
Cell Types ◽  
Reproductive Physiology ◽  
Corticotropin Releasing Factor ◽  
Peptide Sequence ◽  
Gene Duplications ◽  
Terminal Exon ◽  
Numerous Cell ◽  
Multicellular Organisms ◽  
G Protein Coupled

AbstractIn humans, the teneurin gene family consists of four highly conserved paralogous genes that are the result of early vertebrate gene duplications arising from a gene introduced into multicellular organisms from a bacterial ancestor. In vertebrates and humans, the teneurins have become integrated into a number of critical physiological systems including several aspects of reproductive physiology. Structurally complex, these genes possess a sequence in their terminal exon that encodes for a bioactive peptide sequence termed the ‘teneurin C-terminal associated peptide’ (TCAP). The teneurin/TCAP protein forms an intercellular adhesive unit with its receptor, latrophilin, an Adhesion family G-protein coupled receptor. It is present in numerous cell types and has been implicated in gamete migration and gonadal morphology. Moreover, TCAP is highly effective at reducing the corticotropin-releasing factor (CRF) stress response. As a result, TCAP may also play a role in regulating the stress-associated inhibition of reproduction. In addition, the teneurins and TCAP have been implicated in tumorigenesis associated with reproductive tissues. Therefore, the teneurin/TCAP system may offer clinicians a novel biomarker system upon which to diagnose some reproductive pathologies.

Critical role of V1a vasopressin receptor in murine parturition

2021 ◽  
Author(s):  
Hiroyoshi Tsuchiya ◽  
Shyota Fujimura ◽  
Yoko Fujiwara ◽  
Taka-aki Koshimizu
Keyword(s):  
Critical Role ◽  
Contractile Force ◽  
Reproductive Physiology ◽  
Receptor Subtype ◽  
Pituitary Hormone ◽  
Receptor Subtypes ◽  
Expression Of Genes ◽  
Uterine Contractile ◽  
Posterior Pituitary Hormone

Abstract The precise mechanisms of the reproductive physiological processes, such as labor initiation, are poorly understood. Oxytocin (OT) is one of the well-known uterotonics and is clinically adopted as a medication to facilitate childbirth. Vasopressin (VP), a posterior pituitary hormone similar to OT, has also been proposed to be involved in the reproductive physiology. In this study, we found that a total deficiency of V1a receptor subtype (V1aR) in mice resulted in a reduced number of pups, delayed labor initiation, and increased post-delivery hemorrhage compared with those in wild-type mice. Among the VP receptor subtypes, only V1aR was found to be expressed in the murine uterus and its distribution pattern was different from that of the oxytocin receptor (OTR); V1aR expression was mainly distributed in the circular myometrium, whereas OTR was strongly expressed in both the circular and longitudinal myometrium. The maximum contractile force of the circular myometrium, induced by VP or OT, was attenuated in the pregnant uterus of Avpr1a-deficient mice. Contrarily, while OT expression was decreased in the Avpr1a-deficient uterus, OTR expression was significantly increased. These results suggest that V1aR deficiency not only reduces the uterine contractile force but also perturbs the expression of genes responsible for the reproductive physiology. Therefore, V1aR is necessary to exert the maximum contraction of the circular myometrium to deliver pups. This study revealed an important role of V1aR in physiological contraction and term parturition in mice.

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