Differences in sperm migration through cervical mucus in vitro relates to sperm colonization of the oviduct and fertilizing ability in goats

Sperm migration in estrous cervical mucus can be used to measure the ability of spermatozoa to migrate through the genital tract. The relationship of this test with the sperm colonization of the isthmus, and its impact on fertility has not been evaluated in goats. Our objectives were to determine the differences among spermatozoa of different bucks in their ability to penetrate homologous cervical mucus in vitro and to determine the relationship between sperm displacement through cervical mucus and the ability of spermatozoa to colonize the oviduct and penetrate IVM oocytes, in vivo. Sperm migration in cervical mucus was assessed in flat capillary tubes with a phase contrast microscope. In the first experiment, fresh semen was used to establish differences between males in the ability of their spermatozoa to migrate in cervical mucus. In the second experiment, goats in estrus were inseminated with fresh spermatozoa from males with significant differences in mucus migration ability, and sperm numbers were evaluated at the UTJ. In the third experiment, the fertilization efficiency of IVM oocytes transferred to the oviduct of estrous females inseminated with semen from the same males as earlier, was used to assess the relationship between the mucus migration test and the in vivo fertilization performance of their spermatozoa. Spermatozoa from different males varies significantly in sperm migration efficiency in cervical mucus (15.5a +/- 1.2; 14.9a +/- 1.4; 17.5ab +/- 1.2; 17.0ab +/- 1.5; 19.7b +/- 1.2; 20.1b +/- 1.4 mm; media +/- S.E.M. for males A-F, respectively, P < 0.05). Spermatozoa from males with different mucus migration efficiency values produced different sperm populations at the oviduct reservoir of inseminated females (1,233 +/- 92.3 versus 28.8 +/- 17.0 spermatozoa of males with high and low relative migration efficiency, respectively, P < 0.02). Spermatozoa from males with different mucus migration efficiency values have different fertilization rates of IVM oocytes transferred to oviduct (47/96 (49.0%) versus 25/91 (27.5%) for males with high and low relative migration efficiency, respectively, P < 0.05). Cumulative results suggest that sperm migration in cervical mucus is related to the ability of spermatozoa to colonize the oviduct and to fertilize matured oocytes in vivo.     

Diploidy restoration in Wolbachia-infected Muscidifurax uniraptor (Hymenoptera: Pteromalidae)

Thelytokous reproduction, where females produce diploid female offspring without fertilization, can be found in many insects. In some Hymenoptera species, thelytoky is induced by Wolbachia, a group of cytoplasmically inherited bacteria. We compare and contrast early embryonic development in the thelytokous parthenogenetic species Muscidifurax uniraptor with the development of unfertilized eggs of the closely related arrhenotokous species, Muscidifurax raptorellus. In the Wolbachia-infected parasitic wasp M. uniraptor, meiosis and the first mitotic division occur normally. Diploidy restoration is achieved following the completion of the first mitosis. This pattern differs in the timing of diploidy restoration from previously described cases of Wolbachia-associated thelytoky. Results presented here suggest that different cytogenetic mechanisms of diploidy restoration may occur in different species with Wolbachia-induced thelytoky.     

Field and in vitro assay of three methods for freezing ram semen

Glycerol has been the most widely used cryopreservation agent for spermatozoa and a wide range of factors affect its action on sperm viability and fertilizing capacity. We tested three methods for freezing ram semen packed in 0.25 ml straws (final cellular concentration: 100 x 10(6) spz/ml). Method M1: Two-thirds of the final volume of diluent was added as solution A (without glycerol) to the pure semen at 35 degrees C. The sample was cooled to 5 degrees C (-0.30 degrees C/min), one-third of final diluent volume was added as solution B (final concentration of glycerol 4%) and the sample was maintained at 5 degrees C for 2h. It was then frozen in a programmable biofreezer (-20 degrees C/min down to -100 degrees C). Method M2: The sample was diluted with a specific solution at 35 degrees C (final concentration of glycerol 3%), cooled to 5 degrees C (-0.20 degrees C/min) and left for 2h. After that, it was frozen in nitrogen vapours. Method M3: Semen was diluted 1:1 in a specific solution (concentration of glycerol 2%) and cooled to 5 degrees C (-0.25 degrees C/min). The sample was then diluted again in the same solution to the final cellular concentration (final concentration of glycerol 4%). It was left for 1h at 5 degrees C and then frozen in a programmable biofreezer (-20 degrees C/min down to -100 degrees C). Best total motility (TM) and progressive motility (PM) (75.8 and 55.18%) were obtained using Method M3. Methods M1 and M3 gave significantly higher values (P<0.05) for kinetic parameters: average path velocity (VAP) (81.3 and 85.2 microm/s), straight-line velocity (VSL) (72.8 and 77.3 microm/s) and linearity (LIN) (66.6 and 68.8%). Method M2 showed the lowest kinetic parameters of motility (VAP 74.4, VSL 67.3 and LIN 62.5) and the highest percentage of cells with damaged plasma membrane (53.8%). Method M1 gave the worst results in viability and acrosome status assessed using fluorescence probes (31.3%-dead cells with damaged acrosomes-versus 25.4% in M2 and 23.3% in M3). A field trial carried out on fertility showed a significantly higher percentage of pregnant or lambing ewes (P<0.05) with Method M3 (67.3% versus 51.1% for M1 and 58.8% for M2). We concluded that the use of a simple dilution medium (test-fructose-glycerol-egg yolk) with the addition of glycerol (to 2% at 35 degrees C and to 4% at 5 degrees C) in two steps together with a programmable biofreezer was a productive method for freezing ram semen.     

Serine/threonine protein phosphatases PP1 and PP2A are key players in apoptosis

The reversible phosphorylation of proteins controlled by protein kinases and protein phosphatases is a major mechanism that regulates a wide variety of cellular processes. In contrast to C. elegans, recent studies in mammalian cells have highlighted a major role of serine/threonine protein phosphorylation in apoptosis. To illustrate the importance of dephosphorylation processes in apoptosis, this review will focus on recent studies suggesting that the interaction of the serine/threonine protein phosphatase 1 (PP1) and protein phosphatase 2A (PP2A) with certain regulators of the Bcl-2 family is critically involved in the control of apoptosis.     

Liver-specific alpha 2 interferon gene expression results in protection from induced hepatitis

The current therapy for hepatitis B and C is based on systemic administration of recombinant human alpha interferon (r-hIFN-alpha). However, systemic delivery of r-hIFN-alpha is associated with severe side effects, but more importantly, it is effective in only a small percentage of patients. In an effort to maximize IFN-alpha antiviral efficacy, we have explored the therapeutic potential of murine IFN-alpha2 (mIFNalpha2) selectively expressed in the liver. To this end, we have developed a helper-dependent adenovirus vector (HD) containing the mIFN-alpha2 gene under the control of the liver-specific transthyretin promoter (HD-IFN). Comparison with a first-generation adenovirus carrying the same mIFN-alpha2 expression cassette indicates that at certain HD-IFN doses, induction of antiviral genes can be achieved in the absence of detectable circulating mIFN-alpha2. Challenge of injected mice with mouse hepatitis virus type 3 showed that HD-IFN provides high liver protection. Moreover, liver protection was also observed in acute nonviral liver inflammation hepatitis induced by concanavalin A at 1 month postinfection. These results hold promise for the development of a gene therapy treatment for chronic viral hepatitis based on liver-restricted expression of IFN-alpha2.     

Significant In Vivo Anti-Inflammatory Activity of Pytren4Q-Mn a Superoxide Dismutase 2 (SOD2) Mimetic Scorpiand-Like Mn (II) Complex

Background

The clinical use of purified SOD enzymes has strong limitations due to their large molecular size, high production cost and immunogenicity. These limitations could be compensated by using instead synthetic SOD mimetic compounds of low molecular weight.

Background/Methodology

We have recently reported that two SOD mimetic compounds, the Mn^II complexes of the polyamines Pytren2Q and Pytren4Q, displayed high antioxidant activity in bacteria and yeast. Since frequently molecules with antioxidant properties or free-radical scavengers also have anti-inflammatory properties we have assessed the anti-inflammatory potential of Pytren2Q and Pytren4Q Mn^II complexes, in cultured macrophages and in a murine model of inflammation, by measuring the degree of protection they could provide against the cellular injury produced by lipopolisacharide, a bacterial endotoxin.

Principal Findings

In this report we show that the Mn^II complex of Pytren4Q but not that of Pytren2Q effectively protected human cultured THP-1 macrophages and whole mice from the inflammatory effects produced by LPS. These results obtained with two molecules that are isomers highlight the importance of gathering experimental data from animal models of disease in assessing the potential of candidate molecules.

Conclusion/Significance

The effective anti-inflammatory activity of the Mn^II complex of Pytren4Q in addition to its low toxicity, water solubility and ease of production would suggest it is worth taking into consideration for future pharmacological studies.