Protection of chickens from Newcastle and Marek's diseases with a recombinant herpesvirus of turkeys vaccine expressing the Newcastle disease virus fusion protein.

Recombinant strains of herpesvirus of turkeys (HVT) were constructed that contain either the fusion protein gene or the hemagglutinin-neuraminidase gene of Newcastle disease virus (NDV) inserted into a nonessential gene of HVT. Expression of the NDV antigens was regulated from a strong promoter element derived from the Rous sarcoma virus long terminal repeat. Recombinant HVT strains were stable and fully infectious in cell culture and in chickens. Chickens receiving a single intra-abdominal inoculation at 1 day of age with recombinant HVT expressing the NDV fusion protein had an immunological response and were protected (> 90%) against lethal intramuscular challenge at 28 days of age with the neurotropic velogenic NDV strain Texas GB. Recombinant HVT expressing the NDV hemagglutinin-neuraminidase provided partial protection (47%) against the same challenge. Chickens vaccinated with recombinant HVT vaccines had low levels of protection against NDV replication in the trachea when challenged ocularly. Recombinant HVT vaccines and the parent HVT strain provided similar levels of protection to chickens challenged with the very virulent RB1B strain of Marek's disease virus, indicating that insertion of foreign sequences into the HVT genome did not compromise the ability of HVT to protect against Marek's disease.     

Effects of five cryoprotectants on proliferation and differentiation‐related gene expression of frozen‐thawed bovine calf testicular tissue

The cryopreservation of testicular tissue is a potential method for preserving male fertility. However, the effect of cryopreservation on bovine calf testicular tissue is scarce. This study investigated the effect of different cryoprotectants on bovine calf testicular tissue at the molecular level. Testicular tissue from ten immature bovine calves (6 months) was collected after slaughter and cryopreserved in an extender containing different concentrations of the following five cryopreservation solutions (CP): bovine serum albumin (BSA) with 5% dimethyl sulfoxide (DMSO), trehalose with 5% DMSO, DMSO and glycerol and ethylene glycol (EG). After 7‐day cryopreservation, the expression levels of three spermatogonial stem cell (SSC)‐related genes, octamer‐4 (OCT4), KIT ligand (MGF/SCF) and kit oncogene (C‐KIT), were investigated by quantitative PCR (qPCR). The cell viability was highest for the tissues preserved with 30 mg/ml BSA (77.82% ± 1.22) and 40 mg/ml trehalose (74.23% ± 1.16) compared with other groups (p < 0.05), and the level of expression of the three genes was highest with 30 mg/ml BSA (p < 0.05). Compared with other CPs, the 30 mg/ml BSA and 40 mg/ml trehalose have the better cryopreserve protection. The 30 mg/ml BSA is the most viable media for the cryopreservation of testicular tissue from cattle.     

INTRA- AND INTEROBSERVER VARIABILITY OF ULTRASONOGRAPHIC MEASUREMENTS OF THE THYROID GLAND IN HEALTHY BEAGLES

The repeatability of ultrasonographic measurements of the canine thyroid gland was evaluated. The variability of three different parameters (the maximal length, width, and height) within observer, between observer and between dogs was assessed based on three different measurements made by each of three observers infive healthy beagle dogs. From the three parameters, the volume of the gland was estimated using a formula of a rotation ellipse. The height and the volume had the lowest intra- and interobserver variability, while measurements of the length had the biggest intra- and interobserver variability. The mean values, with their 90% confidence interval were: height = 0.53cm [0.33-0.73], length = 2.45cm [2.04-2.85], width = 0.62cm [0.46- 0.78], volume = 0.38 cm3 [0.20-0.55].     

Direct Observation of Vortex Dynamics in Superconducting Films with Regular Arrays of Defects

The microscopic mechanism of the matching effect in a superconductor, which manifested itself as the production of peaks or cusps in the critical current at specific values of the applied magnetic field, was investigated with Lorentz microscopy to allow direct observation of the behavior of vortices in a niobium thin film having a regular array of artificial defects. Vortices were observed to form regular and consequently rigid lattices at the matching magnetic field, at its multiples, and at its fractions. The dynamic observation furthermore revealed that vortices were most difficult to move at the matching field, whereas excess vortices moved easily.     

Control of black thread (Phytophthora palmivora) in hevea brasiliensis with Difolatan

Further investigations have shown that Difolatan applications initially slow down bark renewal; however, the thickness of the living bark becomes about normal after 2 years. The previous finding that Difolatan has no direct effect on latex yield was confirmed. Evidence was obtained that the renewing bark is of normal yield capacity.A suitable colouring agent to check the application of Difolatan is yellow iron oxide; Sterox NJ — a synthetic detergent — should be added to obtain stable suspensions.Promising yield increase was obtained when 0.25–1% 2,4-D was added to the Difolatan suspension in water. The percentage yield increase depends not only on the 2,4-D concentration but also on the use of admixtures, which give more bulk to the 2,4-D coating on the bark. The mixtures which gave the highest yield increase caused the greatest proliferation of the renewing bark and were less effective in controlling the disease. When relatively low concentrations of 2,4-D (up to 0.25%) are mixed with the Difolatan suspension, important yield increases can be obtained without much bark proliferation or loss of fungitoxicity; such applications open up possibilities for mild stimulation of younger tress.Samenvatting Gebleken is dat het fungicide Difolatan, toegepast bij de bestrijding vanPhytophthora palmivora — veroorzaker van een tapvlakziekte, bekend als black thread (Ned. naam: streepjeskanker) — aanvankelijk een remmende invloed heeft op het herstel van deHevea-bast. Echter, na enkele jaren bereikt de levende bast toch een normale dikte. Waarschijnlijk vermindert Difolatan in het begin de activiteit van het kurkcambium, waardoor minder harde bast en kurk worden gevormd. In verscheidene veldproeven werd aangetoond dat Difolatan geen effect heeft op de latexproduktie; de produktiecapaciteit van de herstellende bast zelf is waarschijnlijk ook normaal. Difolatantoepassingen op de bast worden beter zichtbaar door 1% geel ijzeroxide toe te voegen aan de waterige suspensie, welke 1% Difolatan (1.25% van het 80% spuitpoeder) en 0.1% Ortho spray sticker bevat; in dit geval dient nog 0.01% Sterox NJ (een uitvloeier) te worden toegevoegd om een stabiele suspensie te verkrijgen.Hogere rubberopbrengsten werden verkregen door 0.25–1% 2,4-D aan de suspensie toe te voegen. De produktie kan nog verder worden opgevoerd met behulp van hechters, die een dikkere laag residu op de bast achterlaten. De grootste produkties gingen gepaard met sterke woekering van de herstellende bast en een minder bevredigende ziektebestrijding. Evenwel, in betrekkelijk lage 2,4-D concentraties (niet hoger dan 0.25%) werden toch nog belangrijke meeropbrengsten verkregen zonder noemenswaardige bastwoekering of een sterke teruggang in fungitoxische eigenschappen van het mengsel. Deze formuleringen bieden mogelijkheden voor een milde stimulatie van jongere bomen, terwijl tegelijkertijd de streepjeskanker wordt bestreden.     

Dietary amino acids fed in free form or as protein do differently affect amino acid absorption in a rat everted sac model

In the present study, the effect of free amino acid (FAA) diets on the intestinal absorption rate of methionine and leucine was studied ‘ex vivo’ with rats adapted for different periods of time to the diets, using the everted sac method. The adaptation period to the 21% FAA diet with an amino acid content based on casein was either, 0 (no adaptation, N‐ADA), 5 (short‐term adaptation, ST‐ADA), or 26–33 days (long‐term adaptation, LT‐ADA). Within the ST‐ADA and the LT‐ADA groups, three different levels of methionine were included: 50%, 100% and 200% of the level normally present in casein. All diets were iso‐nitrogenous and iso‐caloric. After the adaptation period (0, 5, or 26–33 days), intestinal everted sacs were prepared. Methionine or leucine was added to the medium as transport substrate. The methionine absorption rate of the rats of the LT‐ADA groups was higher than that of the N‐ADA groups. Furthermore, adaptation to 200% dietary methionine levels caused a significantly slower leucine absorption compared to the 100%, and 50% group. Methionine absorption was similar in the 100% and 200% groups, but the absorption of methionine in the 50% group was enhanced in the distal part of the intestines. We concluded that in response diets with 21% FAAs as only amino acid source, amino acid absorption is decreased to avoid toxic effects of high levels of methionine in the circulation.     

Maltoporin (LamB protein) contributes to the virulence and adhesion of Aeromonas veronii TH0426

Aeromonas veronii is one of the main pathogens causing freshwater fish sepsis and ulcer syndrome. More and more cases have shown that it has become an important zoonotic and aquatic agent. In this study, a A. veronii TH0426 mutant strain (ΔlamB) with an in‐frame deletion removed nucleotides 10–1,296 of the lamB gene was firstly constructed to investigate its functions. The results showed that the LD₅₀ value of the mutant ΔlamB to zebrafish and mice was 13.7‐fold and 5.6‐fold higher than those of the wild‐type strain, respectively. The toxicity of wild‐type strain to EPC cells was 2.1‐fold and threefold higher than those of ?lamB when infected for 1 and 2 hr. Furthermore, the ability of biofilm formation and the adhesion and invasion to EPC cells of ?lamB significantly decreased for 5.6‐fold and 1.8‐fold separately. In addition, motility detection result indicated that ?lamB lost the swimming ability. The results of flagellar staining and TEM demonstrated that the flagella of ?lamB were shed. In general, the deletion of lamB gene caused a significant decrease in the virulence and adhesion of A. veronii TH0426, and it can be known that the lamB gene of A. veronii plays a crucial role in the pathogenesis.     

Meta-analysis of the effect of animal maturity on muscle characteristics in different muscles, breeds, and sexes of cattle

The effect of animal maturity on fiber cross-sectional area, percentage of fiber types, activities of isocitrate dehydrogenase (ICDH) and lactate dehydrogenase (LDH), total and insoluble collagen and lipid concentration was investigated in the longis-simus thoracis (LT), semitendinosus (ST), and triceps brachii (TB) muscles. The analysis considered 2,642 muscle samples from bulls, steers, and cows of Aubrac, Charolais, Limousin, Montbéliard, and Salers breeds. For the bulls, the fiber cross-sectional area, percentage of slow oxidative fibers, and ICDH activity showed a quadratic relationship (P < 0.05), and the percentage of fast oxidative-glycolytic and fast glycolytic fibers and LDH activity showed a cubic relationship (P < 0.05) with increased maturity. A linear relationship was observed for the collagen and lipid muscle characteristics. The response equation coefficients for different muscles indicate that development of muscle characteristics is different for each muscle. Compared with the other muscles, ST muscle had a greater fiber cross-sectional area, proportion of fast glycolytic fibers, LDH activity, and collagen content. The LT muscle had a greater proportion of slow-oxidative fibers and lipid (P < 0.05). Within the ST muscle, all characteristics except lipid concentration showed different development between the breeds. Steers showed greater changes in muscle fiber cross-sectional area, percentage of fast oxidative-glycolytic and fast glycolytic fibers, and total lipid in the muscle with increasing maturity compared with bulls. The mean fiber cross-sectional area and percentage of fast glycolytic fibers was greater and the mean lipid concentration was less in bulls compared with steers (P < 0.05). Data for cows were from more mature animals. Muscle characteristics in cows did not show large changes with increasing degree of maturity. Muscle type accounts for a greater proportion of the variation in the muscle characteristics than breed and sex of the animal.     

Queen pheromone blocks aversive learning in young worker bees

Queen mandibular pheromone (QMP) has profound effects on dopamine signaling in the brain of young worker honey bees. As dopamine in insects has been strongly implicated in aversive learning, we examined QMP's impact on associative olfactory learning in bees. We found that QMP blocks aversive learning in young workers, but leaves appetitive learning intact. We postulate that QMP's effects on aversive learning enhance the likelihood that young workers remain in close contact with their queen by preventing them from forming an aversion to their mother's pheromone bouquet. The results provide an interesting twist to a story of success and survival.