Sheep prions with molecular properties intermediate between classical scrapie, BSE and CH1641-scrapie.

Efforts to differentiate bovine spongiform encephalopathy (BSE) from scrapie in prion infected sheep have resulted in effective methods to decide about the absence of BSE. In rare instances uncertainties remain due to assumptions that BSE, classical scrapie and CH1641-a rare scrapie variant-could occur as mixtures. In field samples including those from fallen stock, triplex Western blotting analyses of variations in the molecular properties of the proteinase K resistant part of the disease‑associated form of prion protein (PrP(res)) represents a powerful tool for quick discrimination purposes.

Four independent molecular prion protein parameters for discriminating new cases of C, L, and h bovine spongiform encephalopathy in cattle.

In anticipation of the emergence of more variants of bovine spongiform encephalopathy (BSE), a semiquantitative display of the following four independent molecular diagnostic prion parameters was designed: N terminus, proteinase K (PK) resistance, glycoprofile, and mixed population. One H BSE case, three L BSE cases, six C BSE cases, and one unusual classical BSE (C BSE) case are reported.

Molecular discrimination of atypical bovine spongiform encephalopathy strains from a geographical region spanning a wide area in Europe.

Transmissible spongiform encephalopathy strains can be differentiated by their behavior in bioassays and by molecular analyses of the disease-associated prion protein (PrP) in a posttranslationally transformed conformation (PrPSc). Until recently, isolates from cases of bovine spongiform encephalopathy (BSE) appeared to be very homogeneous. However, a limited number of atypical BSE isolates have recently been identified upon analyses of the disease-associated proteinase K (PK) resistance-associated moiety of PrPSc (PrPres), suggesting the existence of at least two additional BSE PrPres variants.

Rapid and discriminatory diagnosis of scrapie and BSE in retro-pharyngeal lymph nodes of sheep.

Background: Diagnosis based on prion detection in lymph nodes of sheep and goats can improve active surveillance for scrapie and, if it were circulating, for bovine spongiform encephalopathy (BSE). With sizes that allow repetitive testing and a location that is easily accessible at slaughter, retropharyngeal lymph nodes (RLN) are considered suitable organs for testing. Western blotting (WB) of brain homogenates is, in principle, a technique well suited to both detect and discriminate between scrapie and BSE.

Discrimination between scrapie and bovine spongiform encephalopathy in sheep by molecular size, immunoreactivity, and glycoprofile of prion protein.

A procedure for discrimination between scrapie and bovine spongiform encephalopathy (BSE) in sheep is of importance for establishing whether BSE has entered the sheep population. Since BSE has not yet been found in sheep at the farm level, such discrimination procedures can be developed only with experimental sheep BSE. Two distinctive molecular features of the prion protein (PrP)-molecular size and glycosylation profile-in proteinase K digests of brain stem tissue from sheep were used here; upon Western blotting, these features led to an unequivocal discrimination among natural scrapie, experimental scrapie, and experimental BSE.

Determination of the circadian rhythm in plasma corticosterone and catecholamine concentrations in growing broiler breeders using intravenous cannulation.

This paper describes a fast and simple technique for cannulation of the vena cutanea ulnaris (wing vein) in ad libitum fed growing broiler breeders of 5 weeks of age. Twenty-four hours after cannulation, blood was sampled every 4 h during 24 h. The circadian rhythm in plasma corticosterone and catecholamine concentrations was determined for the first time in growing broiler breeders.

The major bovine mastitis pathogens have different cell tropisms in cultures of bovine mammary gland cells.

We previously showed that Staphylococcus aureus cells adhered mainly to an elongated cell type, present in cultures of bovine mammary gland cells. Moreover, we showed that this adhesion was mediated by binding to fibronectin. The same in vitro model was used here, to study adhesion of other important mastitis pathogens.

Behavioural and physiological consequences of acute social defeat in growing gilts: effects of the social environment.

Endocrine, behavioural and immunologic processes, together with body growth, were evaluated in gilts that were defeated at 10 weeks of age in resident-intruder tests. Immediately after defeat, gilts were either separated from or reunited with a familiar conspecific (litter-mate; always a barrow). Gilts were assigned to one of four treatments: (a) DI: defeat, followed by isolation (separation from original litter-mate; n=8); (b) I: no defeat, isolation (control group; n=9); (c) DP; defeat, followed by pair-housing (reunion with original litter-mate; n=8); and (d) P: no defeat, pair-housing (control group; n=8).

Effects of repeated jugular puncture on plasma cortisol concentrations in loose-housed dairy cows.

In three experiments, the effects of venipuncture on plasma cortisol concentrations were studied in loose-housed dairy cows. In Exp. 1, two blood samples were collected 18 min apart on three alternate days from 20 dairy cows for studying their adrenocortical response to a single venipuncture.

A time-resolved fluoroimmunoassay for cortisol in unextracted bovine plasma or serum with optimized procedures to eliminate steroid binding protein interference and to minimize non-specific streptavidin-europium binding.

A time-resolved fluoroimmunoassay (TR-FIA) for human salivary cortisol was adapted for the measurement of cortisol in unextracted bovine blood plasma and serum. It has been demonstrated that the binding of cortisol binding plasma proteins (CBPP) to the cortisol-biotin primary probe cannot be eliminated by means of cortisol releasing agents. Complete inactivation of CBPP was achieved by heating water diluted samples for 30 min at 80 degrees C.

New GnRH-like peptide construct to optimize efficient immunocastration of male pigs by immunoneutralization of GnRH.

Castration of male pigs is routinely performed in order to prevent the occurrence of boar taint in pig carcasses. However, boar taint can also be eliminated by immunological castration using a synthetic peptide vaccine against GnRH. For pig farming, to make immunocastration a feasible alternative method to surgical castration, the composition of the vaccine has to be not only reliable and effective but also cost-efficient and safe.

Genetic variation in the porcine myogenin gene locus.

The myogenin (MYOG) gene fulfills a key function in muscle differentiation by controlling the onset of myoblast fusion and the establishment of myofibers. In meat-producing animals like pigs and cattle, myofiber numbers have been related to growth capacity. We have characterized the porcine MYOG gene to detect genetic variation at this locus and to relate it to growth characteristics.

Assignment of the porcine loci for MYOD1 to chromosome 2 and MYF5 to chromosome 5.

Porcine-specific polymerase chain reaction (PCR) and a pig-rodent somatic cell hybrid panel were used to map two members of the MyoD gene family. MYOD1 was assigned to pig chromosome 2 and MYF5 to chromosome 5.

Isolation of sequences from a random-sequence expression library that mimic viral epitopes.

We describe the use of random peptide sequences for the mapping of antigenic determinants. An oligonucleotide with a completely degenerate sequence of 17 or 23 nucleotides was inserted into a bacterial expression vector. This resulted in an expression library producing random hexa- or octapeptides attached to a beta-galactosidase hybrid protein.

Pubertal development in the male pig: effects of treatment with a long-acting gonadotropin-releasing hormone agonist on plasma luteinizing hormone, follicle stimulating hormone and testosterone.

The effects of a long-acting gonadotropin-releasing hormone (GnRH) agonist, [D-Trp6]-GnRH (GnRH-A) on developmental profiles of plasma luteinizing hormone (LH), follicle stimulation hormone (FSH) and testosterone (T), and pituitary responsiveness to exogenous GnRH were studied in male Dutch Landrace x Large White crossbred pigs from 1 to 30 wk of age. Group 1 control animals (control; n = 12) were injected subcutaneously in the neck with vehicle at 1 and 16 wk of age. Group 2 animals (early treatment; n = 10) were injected with 600 micrograms [D-Trp6]-GnRH at 1 wk and with vehicle at 16 wk.

Development of a high capacity radioimmunoassay procedure: ovine follicle stimulating hormone determination in blood plasma as a model.

A sensitive, specific and accurate homologous radioimmunoassay (RIA) for ovine follicle stimulating hormone (oFSH) has been developed, using a [125I]oFSH tracer and a polyclonal rabbit anti-OFSH-serum at a final dilution of 1:224,000. The separation of free and antibody-bound tracer is based on the double antibody solid phase system. The assay was found to be specific for oFSH; cross-reactivity with oLH, oPrl and oGH was lower than 0.

Effects of morphine and naloxone on plasma levels of LH, FSH, prolactin and growth hormone in the immature male pig.

The effects of acute i.v. administration of gonadotrophin-releasing hormone (GnRH; 0.

Prolactin in the developing pig.

Prolactin (PRL) was determined in plasma of fetal pigs from 40 days post coitum (d.p.c.

Chronic GnRH administration in prepubertal male pigs. A model to evaluate the effects of GnRH treatment in cryptorchidism.

The effect of chronic pulsatile low-dose GnRH treatment on the juvenile testis and associated structures was evaluated in relation to hormonal parameters in the peripheral blood in the pig. Starting at 8 weeks of age, male pigs (crossbreds of Dutch Landrace and Yorkshire breeds) were injected 6 times daily im with 0, 75 or 250 ng GnRH/kg body weight during 4 weeks. Immediately after the treatment period, a GnRH stimulation test with 750 ng GnRH/kg iv was carried out.