Analysis of differential protein expression in Actinobacillus pleuropneumoniae by Surface Enhanced Laser Desorption Ionisation--ProteinChip (SELDI) technology

Actinobacillus pleuropneumoniae (APP) is the aetiological agent of porcine pleuropneumonia. An increased understanding of its molecular basis of pathogenicity and vaccine development will be facilitated by the availability of sequence data from a complete genome which, by analogy to other bacteria, is predicted to encode many proteins in the molecular mass range 3-20kDa. However, conventional techniques to study bacterial protein expression, such as SDS-PAGE and 2-dimensional electrophoresis, typically focus on the 15-200kDa range. In this study we have evaluated Surface Enhanced Laser Desorption Ionisation-ProteinChip (SELDI) technology for the analysis of protein expression, in particular those of <20kDa, of APP grown under different environmental conditions. Cytoplasmic/periplasmic and outer membrane protein fractions were obtained from the APP wildtype serotype 1 strain 4074 grown in Brain Heart Infusion (BHI) broth (+different concentrations of NAD), BHI containing pig serum or defined medium. Optimum conditions for SELDI profiles included a sample size of 1 microg and the use of sinapinic acid as the energy absorbing matrix. In the <20kDa range, the SELDI profiles obtained from wild-type bacteria grown in rich medium plus 33-66% pig serum were most similar to those grown in defined medium. The SELDI profiles of extracts of the wild-type and of an rpoE mutant were similar although there were clear differences. The results suggest that SELDI is a useful complementary approach to conventional proteomic analytical methods with APP, and presumably other bacterial pathogens, being particularly suited for analysis of proteins in the <20kDa mass range.     

Identification of a novel hemotropic mycoplasma in a splenectomized dog with hemic neoplasia

A 3-year-old sexually intact male Bull Mastiff underwent splenectomy for splenic thrombosis; prior to and after splenectomy, multiple blood transfusions were administered. Two weeks after the procedure, T-cell lymphoproliferative disease was diagnosed. Treatment with prednisone and chlorambucil was initiated, and 2 weeks later, cytologic examination of a blood smear revealed small (0.3 microm), coccoid basophilic bodies on the surface of approximately 70% of the RBCs. Morphologically, these resembled "Candidatus Mycoplasma haemominutum." A polymerase chain reaction assay was used to amplify a partial 16S rRNA sequence in blood obtained from the dog; the product was sequenced and compared with 16S rRNA gene sequences of other hemotropic mycoplasmas. The sequence was 98% homologous to that of "Candidatus M haemominutum", but only 77% homologous to that of M haemocanis and M haemofelis.     

Veterinary school admission interviews, part 3: strategies for increasing interview validity

The veterinary school admission interview is a widely used selection tool, yet concerns persist about its reliability, validity, and cost. Relative to medicine, optometry, and dentistry schools, veterinary schools have been more likely to conduct panel interviews and to fix the interview's weight in selection decisions, strategies that increase interview validity. This article provides strategies for further increasing the veterinary school interview's validity. Interview reliability and validity studies point to key strategies the veterinary school admissions committee can implement before the interview: (1) establishing the interview's purpose(s); (2) conducting a "job" analysis to identify desirable candidate skills, knowledge, and attributes; (3) developing a structured and panel interview where interviewers, if possible, are blind to other admission data; (4) training interviewers; (5) setting a reasonable interview schedule; and (6) determining methods for analyzing applicant data. During the interview, interviewers should proceed through a structured series of steps: (1) open the interview with a specified agenda; (2) probe for information using structured questions and anchored rating scales; (3) close the interview to allow for candidate questions; and (4) evaluate the interview data. After the interview, the admissions committee should (1) analyze the interview data within and across interviewers and (2) analyze the data across all selection tools in order to assign relative weights to the selection tools.     

Effects of contact dermatitis on hepatic gene expression in broilers

1.?Severe foot and hock dermatitis in broiler chickens can reduce growth rate and increase susceptibility to bacterial infection, affecting both profitability and welfare. However, little is known about the underlying physiological changes associated with foot and hock lesions.

2.?This study compared global hepatic gene expression in control birds and those with ammonia-induced foot and hock lesions using Agilent 44?K chicken oligonucleotide microarrays (8 birds per group).

3.?In total, 417 genes were differentially expressed of which 174 could be mapped onto the genome. Genes associated with energy metabolism, thyroid hormone activity and cellular control were affected, while there was also evidence of an up-regulation of genes linked to a pro-inflammatory response.

4.?It is conceivable that pain is the underlying cause for the observed changes in energy metabolism genes.

5.?Changes in hepatic gene expression provide new information on how a chicken's physiological mechanisms alter to cope with foot and hock lesions. The findings support other data indicating that birds with increased severity of lesions are likely to be in pain and that growth will be compromised. Reduction of the incidence of dermatitis by improved husbandry should therefore benefit both welfare and commercial performance.     

Leukocytic responses and intestinal mucin dynamics of broilers protected with Enterococcus faecium EF55 and challenged with Salmonella Enteritidis

The protective effect of Enterococcus faecium EF55 in chickens challenged with Salmonella enterica serovar Enteritidis phage type 4 (SE PT4) was assessed. The antibacterial effect on the bacterial microflora in the small intestine in relation to white blood cell count, phenotyping of peripheral blood and intestinal lymphocytes, functional activity of lymphocytes and phagocytes and mucin quantitation were investigated. Day-old chicks (85) were randomly divided into four groups. The probiotic group (EF) and Salmonella + probiotic group (EFSE) received E. faecium EF55 (10⁹ CFU – 3 g/group/day) for 21 days. The Salmonella group (SE) and EFSE group were infected with Salmonella Enteritidis (10⁸ CFU in 0.2 ml PBS) in a single dose per os on day four of the experiment. The control group chicks (C) were fed a commercial diet without added bacteria. Supplementation of EF55 in the diet of the chickens in the EFSE group, challenged with S. Enteritidis, caused the density of the intestinal mucin layer to increase significantly in non-specific regions (duodenum and jejunum), but decrease significantly in target regions (caeca) for S. Enteritidis. Probiotic treatment also appeared to result in a significantly higher number of lymphocytes in peripheral blood and a tendency to increase CD3, CD4, CD8, and IgM positive cells 3 days post-infection with S. Enteritidis. The results demonstrated an antibacterial effect and suggested that EF55 had a moderating effect on intestinal mucin production and leukocytic response in the early phase of S. Enteritidis infection.     

Pig producer attitude towards surgical castration of piglets without anaesthesia versus alternative strategies

A group of 160 Flemish pig farmers (n=160) were surveyed about their attitude towards surgical castration with anaesthesia (SCA) and without (SCN), immunocastration (IC), sperm sexing (SS) and the production of entire males (EM). The farmers' general preference was recorded as SCN>SS>SCA=IC>EM. The farmers' self-reported knowledge of the strategies was associated with their preference for SCA (negatively) and SS (positively). Herd size was correlated with farmers' preference for SCA (negatively) and SS (positively). Farmers perceived surgical castration without anaesthesia as the most favourable strategy in terms of farm profitability, animal performance and effectiveness against boar taint, but they expected the lowest consumer acceptance for this strategy. Surgical castration with anaesthesia was ranked the least favourable in terms of labour conditions. Production of entire males was viewed as the least profitable and the least effective strategy. Sperm sexing was positively perceived, particularly in terms of labour conditions, animal welfare, effectiveness and expected consumer acceptance. The farmers' opinion was quite homogeneous, especially regarding surgical castration without anaesthesia and production of entire males. Increasing our understanding of the farmers' perceptions will hopefully facilitate communication about this intricate issue.