Effect of immunization on reproducvive performance, embryo quality and progesterone in Rasa Aragonesa ewes actively immunized against androstenedione or passively immunized against testosterone

A total of 217 Rasa Aragonesa ewes were used to test two immunization treatments: 1.Active immunization against androstenedione: ewes immunized in previous matings (androstenedione, reimmunized; AR groups, n=58) or not (first immunization; AF groups n=64) were boosted either 2 or 4 wk before mating. 2.Passive immunization against testosterone: antisera were injected either at sponge withdrawal (zero time; T0 group, n=21) or 1 wk previously (Tl group, n=22). We used 52 ewes as controls (C group). Half of each group was used either to record reproductive performance or to embryo viability assessment. Prolificacy was significantly increased in ewes which reached a moderate antibody level, independently of the treatment. Fertility was lower in AR ewes that attained a high antibody titre (P<0.01). The percentage of viable embryos recovered was lower in AF ewes (P<0.01), and in ewes whose testosterone antibody titre was high (P<0.05), compared to C group. It was proven that similar or lower antibody levels were more harmful for ewes from AF and Tl than for ewes from AR or T0 groups. The proportion of nonfertilized recovered ova was not significant. Progesterone levels were notably increased in AR ewes (P<0.001) independently of ovulation rate and were positively correlated to antibody titre at mating (P<0.01) but these events were not observed in T ewes. These findings indicate that after androgen immunoneutralization, only those ewes having antibody titres within a limited range at mating had improved reproductive performance. Further research is needed in order to understand the role that progesterone plays in immunized ewes.     

Experimental dissection of flagellar surface motility in chlamydomonas

Experiments have explored the possible relationships between the flagellar surface motility of chlamydomonas, visualized as translocation of polystyrene beads by paralyzed (pf) mutants (Bloodgood, 1977, J. Cell Biol. 15:983-989), and the capacity of gametic flagella to participate in the mating reaction. While vegetative and gametic flagella bind beads with equal efficiencies and are capable of transporting them along entire flagellar lengths, beads on vegetative flagella are primarily associated with the proximal half of the flagella whereas those of gametic flagella exhibit no such preference. This difference may relate to the "tipping" response of gametes during sexual flagellar agglutination (Goodenough and Jurivich, 1978, J. Cell Biol. 79:680-693). Colchicine, vinblastine, chymotrypsin, cytochalasins B and D, and anti-β-tubulin antiserum are all able to inhibit the binding of beads to the flagellar suface. Trysin digestion and an antiserum directed against whole chlamydomonas flagella have no effect on the ability of flagella to bind beads, but the beads remain immobile. These results suggest that at least two flagellar activities participate in surface motility: (a) bead binding, which may involve a tubulin-like component at the flagellar surface; and (b) bead translocation, which may depend on a second component (e.g. an ATPase) of the flagellar surface. Surface motility is shown to be distinct from gametic adhesiveness per se, but it may participate in concentrating dispersed agglutinins, in driving them toward the flagellar tips, and/or in generating a signal-to-fuse from the flagellar tips to the cell body. Directly supporting these concepts is the observation that bound beads remain immobilized at the flagellar tips during the "tip-locking" stage of pf x pf matings, and the observation that bound ligands such as antibody fail to be tipped by trypsinized flagella.     

Interspecies pregnancy of Spanish ibex (Capra pyrenaica) fetus in domestic goat (Capra hircus) recipients induces abnormally high plasmatic levels of pregnancy-associated glycoprotein

Interspecies embryo transfer could be a valuable tool in preservation programs of endangered species. In this work the results of both interspecific-monospecific (ibex-in-goat) and interspecific-bispecific (mixed-species; ibex+goat-in-goat) embryo transfers in the capra genus are reported. The aim of this work was to compare the PAG plasmatic profiles occurring in these interspecific gestations to those encountered in normal (i.e. intraspecies) pregnancies of Spanish ibex and domestic goat. Spanish Ibex females were superovulated with 9 mg NIADDK-oFSH-17 and embryos were surgically collected 5.5 d after estrus. Two embryos were transferred per recipient. Domestic goat recipients were previously mated either to vasectomized domestic bucks (n=17 females; interspecific-monospecific gestations) or to fertile ones (n=9 females; interspecific-bispecific gestations). Intraspecific pregnancies were obtained by natural mating between males and females of the same species (Spanish ibex: n=6; domestic goat: n=1). Pregnancy rate diagnosed by progesterone was low in both interspecific-monospecific (7/17) and interspecific-bispecific (3/9) transfers. None of the monospecific (0/7) and 2 (2/3) of the bispecific established pregnancies developed to term. Ibex-in-ibex PAG profile showed 2 similar peaks of 60 to 70 ng/mL on Days 34 and 153 of pregnancy, while goat-in-goat had the maximum value (60 to 70 ng/mL) at Day 50, decreasing slightly afterwards until parturition. Mixed-species gestations (ibex+goat in goat) showed a first peak of 500 to 1000 ng/mL on Day 70 and a second one (200 to 500 ng/mL) on Day 140 of pregnancy. Four ibex-in-goat gestations that terminated with the expulsion of dead fetuses at Days 110 to 170 had their maximum PAG values (100 to 700 ng/mL) on Days 60 to 90. We conclude that it is possible to achieve pregnancies after transfer of ibex embryos into domestic goats, but this requires a great change of the PAG profiles, which increase significantly. Live ibex kids can be produced when embryos from both species share the uterus. This is the first report of successful interspecific pregnancies in the capra genus.