This study investigated the effect of summer heat environment on estrous cycles and blood antioxidant levels in Japanese Black cows. A total of 13 non-lactating Japanese Black cows (summer: 9, winter: 4) were examined. Body temperature was measured rectally and intravaginally using a thermometer and data logger, respectively. Estrous behavior was monitored using a radiotelemetric pedometer that recorded walking activity. Rectal temperatures were higher during summer than winter (P<0.001). There was an acute increase in vaginal temperature at the onset of estrus during winter but such an increase was not observed during summer. Walking activity during estrus decreased dramatically in the summer compared to the winter. Duration of estrous cycle was longer in summer (23.4 days, P<0.05) than winter (21.5 days), and the subsequent rise in progesterone concentrations following estrus tended to be delayed in summer. The level of thiobarbituric acid reactive substances (TBARS) in peripheral blood cells was higher during summer (P<0.05), while the levels of superoixde dismutase (SOD), glutathione peroxidase (GPx) and glutathione were lower (P<0.05). These results indicate that high ambient temperature during summer increases both body temperature and oxidative stress, and also reduces signs of estrus in Japanese Black cows.

Licht‐Aquädukt: Periodische mesoporöse Organosilicate absorbieren wegen der dichtgepackten organischen Chromophore in den Porenwänden Licht sehr stark. Die durch 125 Biphenylgruppen in den Porenwänden absorbierte Lichtenergie wird mit fast 100 % Quantenausbeute zu einem einzigen Cumarin‐1‐Molekül in den Mesokanälen geleitet, was eine signifikante Erhöhung der Emission des Cumarin‐1‐Farbstoffs zur Folge hat.

SignificanceIatrogenic failures of assisted reproduction technology could be associated with routine sperm preparation techniques. Limitations of conventional sperm selection methods include the inability to efficiently sort functional spermatozoa and assess sperm fertilization potential. We developed a robust microfluidic sperm sorting system by using a diffuser-type microfluidic sperm sorter device capable of ultrahigh-throughput selection and separation of motile, DNA-intact, and functionally competent sperm. The strategy inclusively targeted the intrinsic traits related to fertility and successfully produced livebirths from low-dose insemination of microfluidic sorted spermatozoa. The fertile subpopulation was identified based on the kinetic and trajectory patterns as the sinuous, transitional cohort. The clinical significance of microfluidic sperm sorting is reflected by the established pregnancy and live births of calves.

Recently, the activity of cathepsins B was found to be correlated inversely with the developmental competence of bovine oocytes. In this study, we investigated (1) the role of intracellular cathepsin B expression and developmental competence as well as the quality of bovine preimplantation embryos, and (2) the effect of cathepsin B inhibitor (E-64) during in vitro culture (IVC) on the development and quality of bovine embryos. After in vitro fertilization (IVF) followed by IVC for 7 days, good and poor quality embryos classified by morphology and developmental rate on days 2, 4, and 7 were assessed for cathepsin B expression and activity. To investigate the effect of cathepsin B inhibition on embryonic development, putative zygotes were cultured with or without E-64, followed by evaluation of cleavage and blastocyst rates on days 2 and 7, respectively. Embryonic quality was evaluated by both TUNEL staining and total cell number in day-7 blastocysts. In each developmental stage, cathepsin B expression and activity were significantly higher in poor quality embryos than good quality ones. Moreover, addition of E-64 during IVC significantly increased both the blastocyst rate and the total cell number. TUNEL staining revealed that inhibition of cathepsin B significantly decreased the number of apoptotic nuclei in day-7 blastocysts. These results indicate that cathepsin B activity can be useful as a marker for inferior quality embryos. Moreover, inhibition of cathepsin B greatly improves the developmental competence of preimplantation embryos and increases the number of good quality embryos.

Abstract. Heat shock is known to increase the mortality of early stage embryos, but the exact mechanism is unclear. In the present study, we investigated the possibility that the increased mortality is caused by heat shock-generated reactive oxygen species (ROS). The level of ROS was controlled by using β-mercaptoethanol (β-ME), a scavenger of ROS. In vitro-produced 8-cell stage embryos were cultured at 38.5 C or heat-shocked by exposure to 41 C for 6 h with 0, 10 and 50 μM β-ME. Intracellular ROS levels were measured by a fluorescent dye, 2',7'-dichlorodihydrofluorescein diacetate (DCHFDA), and intracellular reduced form of glutathione (GSH) contents were estimated by another fluorescent dye, 4-chloromethyl-6,8-difluoro-7-hydroxycoumarin. Total glutathione content was estimated by the glutathione recycling assay. On day 8 after insemination, heat shock decreased the percentage of embryos that developed to the blastocyst stage and increased intracellular ROS levels, but there was no significant effect on the GSH and total glutathione contents. In contrast, β-ME significantly decreased ROS levels in heat-shocked embryos and increased the GSH and total glutathione concentrations. Ten μM β-ME significantly improved the viability of heat-shocked embryos. β-ME