Efficiency of Two Enucleation Methods Connected to Handmade Cloning to Produce Transgenic Porcine Embryos

The purpose of our work was to establish an efficient-oriented enucleation method to produce transgenic embryos with handmade cloning (HMC). After 41–42 h oocytes maturation, the oocytes were further cultured with or without 0.4 μg/ml demecolcine for 45 min [chemically assisted handmade enucleation (CAHE) group vs polar body (PB) oriented handmade enucleation (OHE) group respectively]. After removal of the cumulus cells and partial digestion of the zona pellucida, oocytes with visible extrusion cones and/or polar bodies attached to the surface were subjected to oriented bisection. Putative cytoplasts without extrusion cones or PB were selected as recipients. Two cytoplasts were electrofused with one transgenic fibroblasts expressing green fluorescent protein (GFP), while non-transgenic fibroblasts were used as controls. Reconstructed embryos were cultured in Well of Wells (WOWs) with porcine zygote medium 3 (PZM-3) after activation. Cleavage and blastocyst rates were registered on day 2 and day 7 of in vitro culture respectively. Meanwhile, the total blastocyst cell number was counted on day 7. We found that the difference was only observed between blastocyst rates (38.6 ± 2% vs 48.1 ± 3%) of cloned embryos with GFP transgenic fibroblast cells after CAHE vs OHE. With adjusted time-lapse for zonae-free cloned embryos cultured in WOWs with PZM-3, it was obvious that in vitro developmental competence after CAHE was compromised when compared with the OHE method. OHE enucleation method seems to be a potential superior alternative method used for somatic cell nuclear transfer (SCNT) with transgenic fibroblast cells.     

Classical swine fever virus in plasma and peripheral blood mononuclear cells of acutely infected swine

The distribution of classical swine fever virus (CSFV) in plasma, monocytes, T and B lymphocytes in peripheral blood was monitored during experimentally induced acute classical swine fever infection in piglets. Six piglets were infected with 10(3.8) TCID50 of virus and blood samples taken up to 18 days post-inoculation (p.i.). Infectious virus was detected in monocytes, T and B lymphocytes to similar titres in five of the six infected piglets. Infectious virus was detected earlier in plasma than in any of the mononuclear cell subpopulations. No significant difference was observed in the period of time in which virus could be isolated from the three cell subpopulations. While a progressive lymphopenia developed, a marked B cell depletion was observed. However, B cells were apparently replaced by non-IgM-bearing mononuclear cells, as the proportion 'total lymphocyte/total leucocytes' remained unaltered throughout the experiment. Virus titres in plasma and peripheral blood mononuclear cells showed a tendency to increase as the disease progressed to its outcome.     

Experimental infection of calves with a gI, gE, US9 negative bovine herpesvirus type 5

In this work, a role for the genes encoding glycoproteins I (gI) and E (gE) and the US9 protein of bovine herpesvirus type 5 (BHV-5) in neuropathogenicity and reactivation of latent infections was examined. Calves infected intranasally with a gI/gE/US9 deleted recombinant shed up to 10(2.85) TCID50/ml infectious virus in nasal secretions. Calves infected with the wild type BHV-5 parental virus shed up to 10(5) TCID50/ml virus. No signs of disease were observed in calves infected with the recombinant virus, whereas those infected with wild type virus displayed respiratory and neurological signs. The recombinant was only able to reach the basal portions of the central nervous system. In contrast, wild type virus was found widespread within the brain. Reactivation with dexamethasone 60 days post-infection resulted in reactivation of wild type virus, whereas the recombinant virus could not be reactivated. These studies demonstrate that genes gI, gE and US9 of BHV-5 are important for its neuropathogenicity and its ability to reactive from latency.     

Oesophageal compliance in naturally occurring canine megaoesophagus

SUMMARY The passive blomechanical property of oesophageal compliance (OC) was measured in 8 naturally occurring cases of canine megaoesophagus, 8 matched control and 7 vagotomised control dogs. Of the 8 dogs with megaoesophagus, 6 had congenital Idiopathic megaoesophagus and 2 had secondary megaoesophagus attributable to generalised skeletal muscle disease. Stepwise distension of the whole oesophagus was employed for measurement of OC at the 4.0 and 8.0 mL/kg Injected volume steps within the control volume range (0 to 12.0 mL/kg). At both Injected volume steps OC was higher In megaoesophagus dogs than in either matched control or vagotomised control dogs (P / 0.01 In both cases), and no significant difference was observed In OC between matched control and vagotomised control dogs. No correlation was demonstrated between OC and the estimated duration of clinical signs of dogs with megaoesophagus. These findings suggest that In most cases of canine megaoesophagus the viscoelastic properties of the oesophageal wall are significantly altered, that In such cases the disorder is unlikely to be purely dynamic and that processes other than the duration of oesophageal dilatation are responsible for the alteration in oesophageal wall blomechanical properties. The relevance of these findings to current concepts on pathophysiological mechanisms underlying the evolution and resolution of various forms of canine megaoesophagus Is discussed.     

The use of a random regression model to account for change in racing speed of German trotters with increasing age

In a genetic analysis of German trotters, the performance trait racing time per km was analysed by using a random regression model on six different age classes (2‐, 3‐, 4‐, 5‐ and 6‐year‐old and older trotters; the age class of 3‐year‐old trotters was additionally divided by birth months of horses into two seasons). The best‐fitting random regression model for the trait racing time per km on six age classes included as fixed effects sex, race track, condition of race track (fitted as second‐order polynomial on age), distance of race and each driver (fitted as first‐order polynomial on age) as well as the year‐season (fitted independent of age). The random additive genetic and permanent environmental effects were fitted as second‐order polynomials on age. Data consisted of 138 620 performance observations from 2373 trotters and the pedigree data contained 9952 horses from a four‐generation pedigree. Heritabilities for racing time per km increased from 0.01 to 0.18 at age classes from 2‐ to 4‐year‐old trotters, then slightly decreased for 5 year and substantially decreased for 6‐year‐old horses. Genetic correlations of racing time per km among the six age classes were very high (r_g = 0.82–0.99). Heritability was h² = 0.13 when using a repeatability animal model for racing time per km considering the six age classes as fixed effect. Breeding values using repeatability analysis over all and within age classes resulted in slightly different ranking of trotters than those using random regression analysis. When using random regression analysis almost no reranking of trotters over time took place. Generally, the analyses showed that using a random regression model improved the accuracy of selection of trotters over age classes.     

Climate Change During the Last Deglaciation in Antarctica

Greenland ice core records provide clear evidence of rapid changes in climate in a variety of climate indicators. In this work, rapid climate change events in the Northern and Southern hemispheres are compared on the basis of an examination of changes in atmospheric circulation developed from two ice cores. High-resolution glaciochemical series, covering the period 10,000 to 16,000 years ago, from a central Greenland ice core and a new site in east Antarctica display similar variability. These findings suggest that rapid climate change events occur more frequently in Antarctica than previously demonstrated.     

Effects of continuous and periodic feeding by electronic feeders on accuracy of measuring feed intake information and their genetic association with growth performances

The objective of the study was to analyse the effects of different feeding and recording regimes by electronic feeding stations on growth rate, feed intake and feed intake behaviour. A total of 563 boars of three dam lines were group‐penned and fed ad libitum during an age‐dependent performance test. Of this total, 219 were fed during the entire performance test period of 10 weeks by electronic feeding stations (continuous feeding regime). Based on this feeding regime, no differences were found in feed intake and feed intake behaviour when considering information from either all weeks or every second week. A second group of 344 boars was fed during test weeks 1, 3, 5, 7 and 9 by electronic feeding stations and in the remaining weeks feed was supplied using conventional feeders without recording feed intake (periodic feeding regime). Growth rate and backfat thickness were non‐significantly different between feeding regimes, but significant differences were found between the periodic and continuous feeding regime in daily feed intake (2218 versus 2544 g) and behavioural traits such as visits per day (5.4 versus 7.2), time per day (57.1 versus 63.5 min), time per visit (12.5 versus 11.4 min), and feed intake rate (41.5 versus 43.4 g). Furthermore, the effect of test days on estimation of feed intake was analysed. In the periodic feeding regime, only the exclusion of the first 2 days of each week with recording showed a significant improvement of prediction of feed intake. Based on this daily information, differences in feed intake between feeding regimes decreased (2492 versus 2592 g), whereas visits per day, time per visit and feed intake per visit still differed significantly between periodic and continuous feeding regimes (5.7 versus 7.2; 13.5 versus 11.6 min; and 541 versus 467 g, respectively). Differences were also observed for genetic correlations among behavioural traits between the periodic and continuous feeding regimes, e.g. for daily feed intake and feed intake rate with time per visit (0.47 versus –0.07; –0.16 versus –0.57) and with feed intake per visit (0.81 versus 0.17; 0.58 versus –0.08). Based on the present results a continuous feeding regime was recommended in order to avoid the effect of repeated adaptation. This feeding regime also delivers a greater amount of reliable information and increases the accuracy of prediction of feed intake capacity. In case of limited test capacities and measuring feed intake in particular periods, the first two test days of each period with recording should be excluded to obtain more reliable feed intake information.     

Biomimetic Pathways for Assembling Inorganic Thin Films

Living organisms construct various forms of laminated nanocomposites through directed nucleation and growth of inorganics at self-assembled organic templates at temperatures below 100°C and in aqueous solutions. Recent research has focused on the use of functionalized organic surfaces to form continuous thin films of single-phase ceramics. Continuous thin films of mesostructured silicates have also been formed on hydrophobic and hydrophilic surfaces through a two-step mechanism. First, under acidic conditions, surfactant micellar structures are self-assembled at the solid/liquid interface, and second, inorganic precursors condense to form an inorganic-organic nanocomposite. Epitaxial coordination of adsorbed surfactant tubules is observed on mica and graphite substrates, whereas a random arrangement is observed on amorphous silica. The ability to process ceramic-organic nanocomposite films by these methods provides new technological opportunities.