Single layer centrifugation of fresh dromedary camel semen improves sperm quality and in vitro fertilization capacity compared with simple sperm washing

Single layer centrifugation (SLC) through a colloid is a tool for selecting viable mammalian spermatozoa but has not been used previously for fresh dromedary camel sperm. Semen from six camels (2 ejaculates/male) was diluted 1:5 (v:v) or 1:10 (v:v) in a Tris–citrate–fructose buffer for mechanical liquefaction by gentle pipetting. Following liquefaction, semen was processed either by SLC or by centrifugation without a colloid (control). Total and progressive motilities, CASA kinematics, vitality and acrosome integrity (eosin–nigrosin) and plasma membrane integrity (Hypo‐osmotic swelling test; HOST), and fertilizing ability in a heterologous assay (zona‐free goat oocytes) were evaluated. Both total (p = .003) and progressive motilities (p = .003) were higher in SLC‐processed than in control semen samples, irrespective of dilution. Positive HOST values increased when using colloid in 1:5 (p = .001) and 1:10 dilution (p = .010). Colloid‐selected sperm had higher penetration rates than controls (p < .001 and p = .02 for 1:5 and 1:10 dilutions, respectively). However, only the SLC sperm at 1:5 dilution showed higher percentages of pronuclear formation (p = .02) than controls. Dilution effect was only significant for total motility before in vitro fertilization, with higher values for the 1:5 dilution (p = .033). The recovery rates of motile sperm between dilutions were similar (26.1% vs 35.4%; p = .226). In conclusion, SLC is a promising tool for selecting functional dromedary camel sperm and warrants more research.     

Neuroendocrine,Metabolic and Genomic Cues Signalling the Onset of Puberty in Females

Puberty is the result of a dynamic interaction between genetic factors and environmental cues, all of which lead to the attainment of reproductive capacity. Thus, significant changes in hormone secretion occur from the pre‐pubertal to the pubertal stage. The objective of this review is to provide an update of some endocrine, physiological, metabolic and genetic concepts involved in the establishment of the hypothalamic‐hypophyseal‐gonadal axis function promoting the onset of the reproductive function during puberty. To achieve this purpose, basic aspects of the function of the hypothalamic‐hypophyseal‐gonadal axis, the control of the axis by neurotransmitters and the interaction between reproductive function and metabolic status will be considered. Finally, the role of the novel kisspeptin system and the GPR54 receptor as modulators of puberty will be considered, in addition to the hierarchical expression of the main genes acting as regulators of the onset of puberty.     

High frequency, cell type-specific visualization of fluorescent-tagged genomic sites in interphase and mitotic cells of living Arabidopsis plants

Background  

Interphase chromosome organization and dynamics can be studied in living cells using fluorescent tagging techniques that exploit bacterial operator/repressor systems and auto-fluorescent proteins. A nuclear-localized Repressor Protein-Fluorescent Protein (RP-FP) fusion protein binds to operator repeats integrated as transgene arrays at defined locations in the genome. Under a fluorescence microscope, the tagged sites appear as bright fluorescent dots in living cells. This technique has been used successfully in plants, but is often hampered by low expression of genes encoding RP-FP fusion proteins, perhaps owing to one or more gene silencing mechanisms that are prevalent in plant cells.     

Direct effects of induced parturition on subsequent reproductive performance of dairy cows from commercial herds in south-western Victoria

SUMMARY Reproductive performance was compared between cows whose previous parturition was induced and non-induced cows with similar calving dates, in 49 winter-calving, pasture-fed, commercial dairy herds in south-western Victoria. Parturition was induced in winter when most cows were between 27 and 35 weeks of pregnancy. Reproductive performance was assessed during the next mating period after induction which was mainly in spring of the same year. Percentages of cows in induced and untreated groups that were not pregnant after the mating period (9.0% and 7.2%, respectively) did not differ significantly. Induction tended to increase the percentage of cows of unknown pregnancy status. Mean percentages for induced and untreated groups were 11.5% and 7.9%, respectively. Induced and untreated groups calved at similar intervals after the planned start of calving in the following year, and the percentages of groups that required induction in that year did not differ significantly. The direct effects of induced parturition on reproduction were therefore concluded to be minimal. In seasonal calving herds, improvements in reproductive performance could be expected among cows whose calving dates were altered substantially by induction, due to increased intervals from calving to mating start date .     

Characterisation of the syncytia formed by VHS salmonid rhabdovirus G gene transfected cells

Protein G expression and cell-to-cell fusion of cells transfected with the G gene of viral haemorrhagic septicaemia virus (VHSV) has been characterised. The presence of protein G in the membrane of transfected cells was confirmed by staining with Abs (Abs) and FACS. The subsequent formation of syncytia by membrane fusion of transfected cells required transfection with a wild type G gene and a low pH step. Mice Abs made against the protein G regions involved in fusion and neutralising monoclonal Abs (MAbs) as well as MAbs against some linear epitopes inhibited syncytia formation, thus confirming that syncytia formation was G-dependent. Similarly, Abs from trout immunised with purified VHSV or protein G inhibited syncytia formation whereas Abs from non-immunised or non-infected animals did not. Abs from mice or trout with the highest neutralisation titres also showed the highest percentage of inhibition of syncytia. While the main utility of these observations might be to further the understanding of the complex trout antibody response against VHSV and in the follow up of VHSV immunisation attempts, they may also have some future diagnostic potential for countries were work with VHSV is not allowed.     

Ruminal fermentation and degradation patterns, protozoa population and urinary purine derivatives excretion in goats and wethers fed diets based on olive leaves

Olives leaves, accrued during the processing of olive harvests for oil extraction, are poor in N, rich in crude fat and ADF (1.19, 8.03 and 28.2 g/100 g of DM, respectively), and relatively low in condensed tannins (11.1 mg/g of DM). Three experiments were conducted in a 2 x 3 (two animal species: goats vs. wethers; and three experimental diets: olive leaves without or with polyethylene glycol supply and olive leaves supplemented with barley and faba beans) factorial design to evaluate ruminal degradation and passage kinetics (Exp. 1), fermentation pattern and protozoa population (Exp. 2), and urinary purine derivatives excretion (Exp. 3). Polyethylene glycol was supplied to evaluate the effects of condensed tannins contained in olive leaves. Ruminal degradability of CP was low in both goats and wethers, although goats showed higher (P < 0.05) values than wethers. Supplementation of olive leaves with barley and faba beans increased (P < 0.001) ruminal degradability of DM and CP. Both goats and wethers fed olive leaves showed similarly low particulate fractional passage rates (0.021 and 0.023/h, respectively). Ingestion of olive leaves promoted low NH3-N and VFA concentrations, which reflect poor microbial activity. These concentrations, especially that of VFA, increased when barley and faba beans were added. Ingestion of olive leaves affected ruminal protozoa: Entodiniomorphida showed low concentrations and Holotricha completely disappeared. When animals received a diet based on olive leaves, barley, and faba beans, Holotricha appeared in the ruminal liquor and Entodiniomorphida increased (P < 0.001). In goats and wethers fed olive leaves alone, urinary allantoin excretion was very low (163 and 164 micromol/kg BW0.75 in goats and wethers, respectively), and moderate values (352 and 389 micromol/kg BW0.75 in goats and wethers, respectively) were observed when a diet of olive leaves, barley, and faba beans was fed. The polyethylene glycol supply did not have an effect in goats or in wethers, indicating the lack of an effect of condensed tannins in olive leaves. Ingestion of olive leaves promotes a low microbial activity, although its supplementation with readily degraded carbohydrates and protein improves microbial activity and, as a consequence, increases its ruminal degradation. In general, for most of the measured variables, there were no animal species x diet interactions. Thus, goats and wethers had similar ruminal activities when fed diets based on olive leaves.