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12. Acquisition of plasmin activity and induction of arachidonic acid release by Streptococcus suis in contact with human brain microvascular endothelial cells

Author

Jobin, Marie-Claude, Fortin, Julie, Willson, Philip J., Gottschalk, Marcelo, and Grenier, Daniel

Subjects
STREPTOCOCCUS, FIBRINOLYTIC agents, BLOOD plasma, STREPTOCOCCACEAE
Abstract

Abstract: Infections caused by Streptococcus suis, a major swine pathogen, include meningitis, arthritis, pneumonia and septicaemia. In this study, we investigated interactions that may occur between human brain microvascular endothelial cells (HBMEC), the main constituent of the blood–brain barrier, and S. suis. We show that S. suis acquires plasmin activity in a time-dependent manner when in contact with cultured HBMEC. Cell-associated plasmin activity reached a plateau following a 48h co-incubation period. Zymography analysis revealed that HBMEC produce urokinase, which is probably involved in activation of plasminogen bound to S. suis. We also show that a S. suis culture supernatant which possesses both phospholipase C and haemolysin (suilysin) activities was able to induce the release of arachidonic acid from the membrane of HBMEC. Evidence suggests that the action of suilysin on HBMEC may be a prerequisite for the action of additional molecules such as phospholipase C. These new biological effects associated with S. suis may play an important role in the migration of S. suis through the blood–brain barrier and in the modulation of local inflammation. [Copyright &y& Elsevier]

Published
2005
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13. Investigation of a Novel DNase of Streptococcus suisSerotype 2

Author

Fontaine, Michael C., Perez-Casal, Jose, and Willson, Philip J.

Abstract

ABSTRACTA secreted nuclease, SsnA, was identified in the virulent Streptococcus suisisolate SX332 and subsequently in each of the type strains of capsular serotypes 1 through 9. Screening of 258 porcine clinical isolates from surface (nasal mucosa or palatine tonsil) or internal (joint, brain or other internal organ) locations revealed a significant relationship (P< 0.001) between expression of nuclease and isolation from an internal site. A 3,126-bp gene, ssnA, was identified from a phenotypically nuclease-negative pGh9:ISS1insertion mutant, and analysis of the predicted SsnA sequence revealed a 35-amino-acid (aa) secretion signal sequence, a 22-aa DNA-binding domain, and a typical gram-positive cell wall sorting motif. A requirement of Ca2+and Mg2+for SsnA activity was determined, and the substrate specificity was found to be for single- and double-stranded linear DNA. Reverse transcription-PCR experiments revealed that ssnAis expressed throughout all stages of S. suisgrowth, and Western blots with porcine anti-S. suisimmune sera against a recombinant, truncated SsnA derivative (rSsnAΔ) confirmed that SsnA is expressed in vivo. Furthermore, anti-rSsnAΔantibodies were sufficient to neutralize SsnA activity. Analyses of subcellular fractions of SX332 and derived mutants, on DNA-containing polyacrylamide gels and by Western blotting, suggest that SsnA is cell wall located.

Published
2004
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14. An Analysis of the Complete Nucleotide Sequence of the Haemophilus ducreyiBroad-Host-Range Plasmid pLS88

Author

Dixon, Laurie G., Albritton, William L., and Willson, Philip J.

Abstract

We present an analysis of the complete nucleotide sequence of pLS88, a naturally occurring, 4.8-kb broad-host-range plasmid isolated from Haemophilus ducreyiand encoding resistance to sulfonamides, streptomycin, and kanamycin. Sequence analysis of the genes encoding sulfonamide and streptomycin resistance revealed homology to the RSF1010 sulIIand strAgenes. The sulII-strAintergenic region of pLS88 has a 38-bp deletion identical to that of the RSF1010-like plasmid pHD8.1, isolated from Actinobacillus pleuropneumoniae. The kanamycin resistance gene shows strong homology to Tn903, but lacks the inverted repeats of the transposon. No other genes have been identified. The region downstream of the kanamycin resistance gene shows homology to the RSF1010 oriVregion; however, this region is not essential to plasmid replication. The oriof pLS88 is contained within a 1060-bp region and does not appear to contain structures typical of plasmid origins. This region is flanked by DNA showing strong homology to regions both upstream and downstream of the Haemophilus influenzaeROB-1 β-lactamase gene. Because of the small size of the origin. pLS88 appears to resemble the structure of narrow-host-range plasmids, but replicates, via an as yet unidentified mechanism, as a broad-host-range plasmid.

Published
1994
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15. Comparison of Common Antibiotic Therapies for Haemophilus Pleuropneumonia in Pigs

Author

Willson, Philip J. and Osborne, A. Dudley

Subjects
Articles
Abstract

Three experiments were done to evaluate some antibiotic therapies that are used commonly to treat pigs infected with Haemophilus pleuropneumoniae. Haemophilus-free piglets, 12 weeks of age, were challenged in a chamber with an aerosol of H. pleuropneumoniae serotype 1 and were medicated with antibiotics at various times before or after challenge. Antibiotic formulations which are commonly used to treat pneumonia in swine were used. They were chloramphenicol, penicillin, and a long-acting formulation of oxytetracycline given intramuscularly; and oxytetracycline, chloramphenicol and spiromycin (investigated as a potentially useful antibiotic) given in solution as the sole source of drinking water. Infection, disease (death, fever, gross lung lesions) and growth rate were measured in pigs following experimental challenge.The therapeutic effect of these antibiotic formulations was evaluated for prevention of the disease (52 pigs), treatment of acute disease (36 pigs), and treatment of chronic pneumonia (45 pigs). Injectable, long-acting oxytetracycline prevented all manifestations of disease (P0.05) when given 24 hours before challenge. When treatment commenced immediately after the first signs of disease, each of the injected antibiotics reduced death rate (P0.05), but they neither improved average daily gain nor reduced the incidence of infection and lung lesions. Chronically infected carrier pigs were produced by first immunizing them with a Haemophilus vaccine and then challenging them three weeks later. None of the treatments reduced the proportion of carriers of H. pleuropneumoniae.

Published
1985

16. Detection of Actinobacillus pleuropneumoniae Infection in Pigs

Author

Willson, Philip J., Falk, Gloria, and Klashinsky, Sandra

Subjects
animal diseases, Articles, respiratory system, bacterial infections and mycoses, respiratory tract diseases
Abstract

It is difficult to control the spread of porcine haemophilus pleuropneumonia caused by Actinobacillus pleuropneumoniae because there is no sensitive and specific way to accurately determine whether or not a pig herd is infected. This paper reports bacteriological and serological techniques used to detect A. pleuropneumoniae infection in pigs from a herd with endemic disease.The bacteria were isolated from the anterior nasal mucosa of grower pigs, but not from younger or older pigs. Bacteriological culture of several tissues from the respiratory tract showed that nine of ten young finishing pigs were infected, but culture of lung tissue from slaughtered hogs detected infection in only 39 of 288 (13.5%). Both cooler storage temperature and use of selective medium prolonged the time that lung tissue could be stored and the organism still recovered. An enzyme-linked immunosorbent assay detected serotype-specific antibodies in serum of infected pigs.

Published
1987

19. Étude des interactions entre Streptococcus suis et des neutrophiles porcins

Author

Chabot-Roy, Geneviève, Gottschalk, Marcelo, Segura, Mariela, and Willson, Philip J.

Subjects
Capsule polysaccharidique, Effet bactéricide, Cytotoxicité, Phagocytose, Anticorps, Neutrophiles, S. suis, Suilysine, Complément
Abstract

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Published
2006

20. Gender-related tumor necrosis factor-alpha responses in naïve volunteers with Toll-like receptor 4 polymorphisms exposed in a swine confinement facility.

Author

Senthilselvan A, Chénard L, Kirychuk S, Predicala B, Schwartz DA, Burch LH, Rennie DC, Willson PJ, and Dosman JA

Subjects
Adolescent, Adult, Animals, Female, Forced Expiratory Volume, Heterozygote, Homozygote, Humans, Interleukin-6 blood, Interleukin-6 metabolism, Interleukin-8 metabolism, Male, Nasal Lavage Fluid immunology, Polymorphism, Genetic, Respiratory Function Tests, Sex Factors, Swine, Vital Capacity, Young Adult, Air Pollutants, Occupational adverse effects, Respiratory System immunology, Toll-Like Receptor 4 genetics, Tumor Necrosis Factor-alpha blood
Abstract

The aim of this work is to better understand the responses of people that are exposed to agricultural organic dust and other factors in modern swine production. We investigated the effects of toll-like receptor 4 (TLR4) genotype and gender on respiratory responses of naïve volunteers (18-28 years) to swine barn exposure. Non-smoking healthy subjects (16 men and 13 women) with TLR4 299 (Asp299Gly) and/or 399 (Thr399Ile) polymorphisms (TLR4 299/399) and age-sex matched subjects with TLR4 wild-type alleles spent 5 h in a nonexposed environment (baseline day) and 5 h in a swine facility (exposure day). The results showed significant decreases between baseline and exposure days in across-shift forced vital capacity (FVC), forced expiratory volume in 1 second (FEV(1)), forced midexpiratory flow rate (FEF(25-75)), and FEV(1)/FVC ratio and in methacholine concentration that reduced FEV1 by 20% (PC(20)) in all groups; however, there were no differences by sex or genotype. Similarly, nasal cytokines, serum cytokines, and blood neutrophil count increased after exposure; in contrast, however, these were influenced by gender. The increase in serum tumor necrosis factor-alpha (TNF-alpha) between baseline and exposure was gender-dependent with male sex associated with a significant increase in the wild-type group and female sex associated with a significant increase in the polymorphic group. These results suggest that for persons exposed to a swine facility, one's immunological response varies with gender as well as TLR4 genotype.

Published
2009
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