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The aim of this study is to verify the efficacy of a superovulation treatment with 3 injections of pituitary extracts (Stimufol®) 24 hours apart and compare the results to a standard protocol (8 injections 12 hours apart), with a total dose of 500 μg. Twenty-three embryos collections were conducted after two superovulation protocols, the first with 8 injections 12 hours apart and decreasing doses (n = 11, group 1) and the second 3 injections at constant doses 24 hours of interval (n = 12, group 2). The average number of lutea corpora obtained is 9.1 per cow for group 1 and 10.4 in group 2. A total number of 140 embryos were collected with an average of 6.08 per cow. Among the embryos collected, 46 and 56 per cent were transferable respectively in group 1 and 2. A little quality gain was recorded in group 2 with an average transferable embryo of 3.8 against 2.2 for group1. In our study we observed the same efficacy for both treatments with a little quality improvement (almost one transferable embryo) when reducing the number of injections at the time of superovulation treatment, the same gain minimal in elite cows can have a significant economic impact. [ABSTRACT FROM AUTHOR]

Hox collinearity is a spectacular phenomenon that has excited life scientists since its discovery in 1978. Two mechanisms have been proposed to explain the spatially sequential pattern of Hox gene expression in animal embryonic development: interactions among Hox genes, or the progressive opening of chromatin in the Hox clusters, from 3' to 5'. A review of the evidence across different species and developmental stages points to the universal involvement of trans-acting factors and cell--cell interactions. The evidence focuses attention on interactions between Hox genes and on the vertebrate somitogenesis clock. These novel conclusions open new perspectives for the field. [ABSTRACT FROM AUTHOR]

Background. Tadpole codling, Salilota australis (Günther, 1878), (known also as red cod) and southern blue whiting, Micromesistius australis Norman, 1937, are two commercially important species, which spawning grounds are situated in the Falkland waters. Nothing is known about duration of the embryonic development in these fish, whereas these data are necessary to study life cycle strategies as well as for stock management. Because of this, experiments with artificial egg fertilisation were carried out onboard a research boat that was the only way to obtain such an information. Materials and Methods. Eggs from each species were taken from running females captured on their spawning grounds and then fertilised. Egg samples were collected every 6 hours and stage of embryonic development was assigned using a dissecting microscope. Results. Tadpole codling eggs are of 1.20-1.55 mm, with an oil globule of 0.29-0.33 mm, incubation takes between 140-150 h at 6-8.5°C, 40-45 degree-days. Larval size at hatching is ca 2.9 mm TL. Blue whiting eggs are of 1.40-1.55 mm with no oil globule. Development takes from 150 h at a mean temperature of 7.15°C to 200 h at between 5.5 and 6°C, 45-50 degree-days. Larval size at hatching is 2.8-3.0 mm. Conclusion. Duration of embryonic development for commercial southwest Atlantic gadiform fish, tadpole codling, Salilota australis, and southern blue whiting, Micromesistius australis, is documented for the first time. It allows to draw some conclusions about possible mortality during this ontogenetic stage (assuming that daily rates are similar to those in other similar species) and to hypothesise about possible egg transport by currents and interannual spawning grounds' variability. [ABSTRACT FROM AUTHOR]

The article presents a study which investigates the embryonic-abembryonic (Em-Ab) axis of the blastocyst in the porcine parthenogenetic embryo of a pig. It examines whether porcine embryos would exist as an intrinsic property of oocyte itself, and describes the fate of an individual blastomere from a 2-cell-stage parthenogenetic porcine embryo. It mentions that porcine parthenotes were used in investigating the Em-Ab axis in the pig to prevent the topological change caused by polyspermy, and to avoid the influences of sperm entry position. Results show that the fate of an individual blastomere of the porcine parthenogenetic embryo at the 2-cell stage may be an intrinsic property of the oocyte itself.

Abstract: Purpose: The receptor tyrosine kinase of the Eph family is a large group of highly conserved molecules that function in diverse intercellular recognition events. It has been reported that EphB2 is related to caudal remodeling events. The aim of this study is to investigate EphB2 expression in anorectal development in normal and rat embryos with anorectal malformations (ARMs) and attempt to define its role in anorectal morphogenesis. Methods: The ethylenethiourea (ETU) rat model of the ARMs was used in this study. Immunohistochemical analyses and real time quantitative polymerase chain reaction (PCR) were carried out to investigate EphB2 protein localizations and messenger RNA (mRNA) expression levels. (1) Rat embryos with ARMs were obtained by treating pregnant rats (n = 24) with administration of ETU on gestation day (Gd) 10. Normal rat embryos (n = 111) and embryos treated by ETU without ARMs (n = 90) were the control groups, and embryos with ARMs (n = 108) from Gd13 to Gd16 were divided according to the sections taken from specimens. (2) Embryos were sequentially sectioned in the sagittal and transversal planes before staining with a specific antibody to EphB2. Spatiotemporal study was carried out on EphB2 expression. (3) Individual frozen sections were used to manually microdissect the cloaca and anorectal specimens for total RNA extraction. EphB2 expression was evaluated by real time quantitative PCR. Results: On the immunologic labeling study, EphB2 expression was confined to the cloaca in control groups, whereas EphB2 expression was mainly located at the urorectal septum (URS) and cloacal membrane on Gd13 and Gd14. The increased positive expression was observed in the fused tissue of the URS and cloacal membrane on Gd15. On Gd16, the anal membrane broke down, and the rectum was able to be in contact with the anus, and EphB2 expression was then noted in mucous membrane of rectum. EphB2 expression was seen in the cloacal and anorectal tissues of embryos with ARMs. By integrated optical density (IOD) measurement, IOD value of EphB2 protein was significantly lower in the ARM group than that in the control groups on Gd13 to Gd16 (P < .05), respectively. As shown by real time quantitative PCR, EphB2 expression was detected in 3 groups. EphB2 mRNA level increased on Gd13 to Gd16 but gradually decreased after Gd16. The expression level of EphB2 mRNA in the ARM embryos was lower on Gd13 to Gd16 than that in control groups (P < .05). Conclusions: EphB2 expression decreased in the ARM embryos and was confined to URS and cloaca, whereas it was higher in control group. Our data thus indicated that EphB2 molecules possibly contributed to the anorectal morphogenesis and the decreased expression of EphB2 might be related to the development of ARMs. [Copyright &y& Elsevier]