Proton-dependent kinetics of citrate uptake in growing cells of Lactococcus lactis subsp. lactis bv. diacetylactis

Abstract The kinetic analysis of citrate uptake in growing cells of Lactococcus lactis subsp. lactis biovar. diacetylactis identified a proton-dependent transport and suggested the divalent anionic species as the form of citrate transported across cell membranes. The reaction followed Michaelis-Menten kinetics for a two-substrate reaction. The limiting steps were the formation of the ternary complex and the rate of transport. Temperature modified the activity of the permease, increasing the uptake rate.     

Isolation and sequence determination of porcine class II DRB alleles amplified by PCR

The first domain exon of a porcine DRB gene was amplified by the polymerase chain reaction (PCR), and the nucleotide sequence was determined. In a material consisting of 10 unrelated animals, five different alleles were identified, all probably belonging to a single locus designated DRB1. In addition, a non-expressed locus, designated DRBP, was coamplified with DRB1. This pseudogene, containing a single base deletion, also exhibited some variation, but at a very restricted level compared with DRB1. In pairwise comparisons of DRB1 alleles, the number of amino acid substitutions ranged between 6 and 21 out of 83 positions compared.     

Serosurveillance for selected infectious disease agents in wild boars (Sus scrofa) and outdoor pigs in Switzerland

The large abundance of free-ranging wild boars (Sus scrofa) and a trend towards animal friendly outdoor management of domestic pigs lead to an increasing probability of disease transmission between those animal populations. In 2001, an active monitoring was started for classical swine fever (CSF), Aujeszky’s disease (AD) and porcine brucellosis (PB) in wild boars in Switzerland. The objective of this programme was to document the serological status of wild boars regarding the selected pathogens. To continue this serosurveillance, 1,060 wild boar samples were collected during two regular hunting seasons in 2004–2005. Furthermore, in a pilot study, 61 outdoor pigs from 14 farms located in areas with high wild boar densities were sampled in 2004 and serologically tested for AD and PB. All wild boar samples were negative for CSF. Seroprevalence for AD was 2.83% (95% CI 1.91–4.02%). Seroprevalence for PB was 13.5% (95% CI 10.7–16.7%) for the Rose Bengal test and 11.05% (95% CI 8.82–13.61%) for the indirect ELISA. There was no serological evidence for AD in domestic pigs. All tested animals from 13 piggeries were seronegative for PB, but three pigs from the same farm showed doubtful results. Further investigations on the farm did not indicate the presence of PB in the herd. These findings urge the need for better diagnostic tools to obtain reliable results concerning PB prevalence. Since contact and following transmission of infectious agents between infected wild boars and outdoor pigs might occur in the future, it is advisable to include outdoor pigs in areas at risk in routine surveillance programmes.     

New concept of contaminant removal from swine wastewater by a biological treatment process

Pollution from concentrated animal feeding operations (CAFOs) are the most serious pollution source in China now, and swine wastewater contains high concentrations of nutrients such as chemical oxygen demand (COD), biochemical oxygen demand 5 (BOD5), ammonium, and emergent contaminants related to public health. Biological processes are the most popular treatment methods for COD and ammonium removal. Considering the low operation cost, easy maintenance and high removal rate of contaminants in recent years, nitrogen removal via nitrite and real-time control processes using oxidation-reduction potential (ORP) and/or pH as parameters to control the aerobic and anaerobic cycles of a system has received much attention for animal wastewater treatment. During the biological treatment process, the emergent contaminants such as estrogen, antibiotics, and disinfec-tion reagents have been the focus of research recently, and degradation bacteria and resistance bacteria have also been extracted from activated sludge. The microbial analysis technique is also advancement in the field of biodegrada-tion bacteria and resistance bacteria. All of these advance-ments in research serve to improve wastewater treatment and decrease environmental hazards, especially for using manure as a fertilizer source for crop production.     

Quantification of Lawsonia intracellularis in porcine faeces by real‐time PCR

Aim: To develop and to validate a method for the quantification of Lawsonia intracellularis in porcine faeces by real‐time PCR. Methods and Results: A real‐time PCR including a calibrator based on plasmid DNA for quantification by means of ΔΔCt method was evaluated. The parameters specificity, detection limit, quantification limit, linearity, range, repeatability, precision and recovery were validated. The detection limit of the agent was 1 copy per reaction, and quantification was reliable between 10¹ and 10⁷ copies per μl reaction volume. The linearity calculated by logistic regression revealed a slope of ?3·329 reflecting an efficiency of 99·7% for the assay. Moreover, it was shown that storage of samples and repetition of tests including DNA isolation by same or other investigators did not influence the outcome. Conclusion: The quantification method described herein revealed consistent results for the quantitation of L. intracellularis in porcine faeces samples. Significance and Impact of the Study: In contrast to common PCR in combination with gel electrophoresis, this validated quantification method based on real‐time PCR enhances a reliable quantification and is even more sensitive.     

Effect of Liquid Swine Manure on Hatch and Viability of Heterodera glycines

Experiments were conducted in the laboratory and greenhouse to determine the effect of raw and anaerobically digested liquid swine manures on the hatch and viability of Heterodera glycines, the soybean cyst nematode. Anaerobic digestion was performed for 15 and 35 days to enrich volatile fatty acids (VFA) and ammonium (NH₄ ⁺), respectively. All filtrates of the raw, VFA-enriched, and NH₄ ⁺-enriched manures at 10⁻¹ to 250⁻¹ dilutions inhibited H. glycines hatch, and the reduction of hatch was increased with increasing concentration of the manure. Cumulative hatch at day 21 was only 2.1% to 3.7% in the 10⁻¹ dilution manures, while the hatch in water was 21% to 27.3%. The high concentrations appeared to be lethal to some eggs. Most second-stage juveniles (J2) of H. glycines were killed when incubated for 8 hours in the manure filtrate at the original concentration (>90% mortality) or for 48 hours at the 64⁻¹ dilution (> 82% mortality). When J2 were treated with the manures at 10⁻¹ to 250⁻¹ dilutions for 4 hours, only the 10⁻¹ dilution of VFA-enriched and raw manures resulted in a lower number of J2 that penetrated soybean roots as compared with lower concentrations. The VFA-enriched manure was the best, raw manure intermediate, and NH₄ ⁺-enriched manure the least effective in inhibiting H. glycines hatch and killing eggs and J2.     

Comparative studies on cell lines established from normal and radiation-exposed miniature swine

Summary Cloned cell lines were established from two swine with radiation-induced myeloproliferative disorders, including one cell culture from an animal with myelogenous leukemia and one from an animal with myeloid metaplasia. A third cloned cell line with similar morphology was established from pooled normal fetal swine cornea to compare the growth characteristics of cells from normal and irradiated swine. All three cell lines grew as foci of aggregated cells and were able to form macroscopic colonies in semisolid agar medium. The lack of normal mechanisms of contact inhibition and the observed aneuploidy indicated that these cells were morphologically transformed. Further, the cloned cells caused tumors in nude mice, clearly indicating that these cells were also malignantly transformed. A major difference between these cell lines was that type C viruses were observed only in the cells derived from swine with myeloproliferative disorders. Work supported by the U.S. Department of Energy under Contract EY-76-C-06-1830.     

Relationship between fumonisin contamination of feed and mystery swine disease

Fumonisin is a recently identified mycotoxin that has been shown to be the cause of pulmonary edema disease in swine and leukoencephalomalacia in horses. Mystery Swine Disease (MSD), is an economically devastating disease complex of unknown etiology that has been reported to have occurred in several swine producing states since 1988. To determine the relationship between MSD and fumonisin, a case-control study was carried out in Illinois in mid-1990. Feed samples collected from 12 case and 9 control farms were analyzed for fumonisin. Sera from swine on all farms was screened for titers against encephalomyocarditis (EMC) virus and concentrations of alpha-1 acid glycoprotein (an acute phase reactive protein). Fumonisin concentrations 20 ppm were found on 1 control farm (1/9) and 8 case farms (8/12). Titers against EMC virus ( 116) were found on 5 control farms (5/9) and on 6 case farms (6/12). Farms with 20 ppm fumonisin in the feed were at significantly increased risk (OR= 11.2, Fisher's exact test p=0.037) for MSD. Furthermore, the ² test for trend was significant (p= 0.017), meaning that as the level of fumonisin in the feed increased, the risk of MSD also increased. The presence of EMC virus titers in the sow herd was not a significant risk for MSD (OR =1.25, Fisher's exact test p=0.75). Alpha-1 acid glycoprotein concentrations obtained from 2-week old nursing pigs differed significantly (p=0.0005) between MSD case and control herds.     

A behavioral response of swine to a 60-Hz electric field

It has been shown that rats, given the choice, will spend more time out of a 60-Hz electric field than in it at field strengths ? 75 kV/m. This paper describes research to examine the relevance of these data to a different species, the pig. Miniature pigs that had been exposed to a 60-Hz electric field at 30 kV/m for 20 h/day, 7 days/week for as long as 6 months, were tested for their preference for the presence or absence of the field during a 23.5-h period. Similar to earlier results with rats, miniature pigs spent more time out of the electric field than in it during the sleeping period.