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R Sellwood

Publications and source records attributed to R Sellwood.

At least 19 recordsLinked to original sources
PubMed1997

Extracellular DNA from Serpulina hyodysenteriae consists of 6.5 kbp random fragments of chromosomal DNA.

Preparations of chromosomal DNA from a number of Serpulina hyodysenteriae strains have shown, using agarose gel electrophoresis, the presence of an additional band with a mobility similar to that of a 6.5 kbp linear DNA fragment. Analysis showed that this is not a plasmid but rather a form of extracellular DNA like that observed for Gram-negative bacteria. However, unlike the extracellular DNA from Gram-negative bacteria, which showed a similar band profile to that of the DNA from whole cells, that from S. hyodysenteriae consisted primarily of fragments of a fixed 6.5 kbp.

Bacterial Outer Membrane Proteins↗
PubMed1995

Expression of the SmpA outer membrane lipoprotein of Serpulina hyodysenteriae strain P18A in vivo.

An ELISA has been developed using a monoclonal antibody (F325 AC4) to the SmpA surface lipoprotein of Serpulina hyodysenteriae strain P18A when grown in vitro. The lower level of detection of the ELISA was approximately 5 x 10(6) spirochaetes/ml when spirochaetes were either resuspended in phosphate buffered saline or in pig faeces. When pigs were challenged with S. hyodysenteriae strain P18A the lipoprotein was detected in the faeces of pigs by ELISA when the numbers of spirochaetes excreted was greater than 10(6) per g of faeces. After onset of clinical signs in the pig, expression of SmpA was not detected by ELISA or by Western blotting using either monoclonal antibody F325 AC4 or polyclonal antiserum B50 against the SmpA antigen. However, when the in vivo grown spirochaetes were subsequently cultured in vitro expression of SmpA was detected by Western blotting. In the mouse model of swine dysentery S. hyodysenteriae spirochaetes obtained from mice with gross lesions also did not express SmpA. It was concluded that the apparent lack of expression may have been the result of environmental regulation of gene expression or antigenic variation and was not due to denaturation of the antigen in vivo.

Animals↗
PubMed1995

Distribution of the smpA gene from Serpulina hyodysenteriae among intestinal spirochaetes.

Forty intestinal spirochaete strains were investigated for nucleotide sequences related to the smpA locus from Serpulina hyodysenteriae by Southern hybridization of chromosomal DNA using the smpA locus from S. hyodysenteriae strain P18A as a probe and by PCR using primers internal to the smpA gene. The intensity of the hybridization signal at high stringency and positive PCR results suggested that 12 S. hyodysenteriae strains possessed a similar nucleotide sequence. PCR was negative for another 12 S. hyodysenteriae strains and the hybridization signal obtained from 11 of these was weak and one was negative. All S. hyodysenteriae strains hybridized under low stringency conditions. These results indicated that there is variation among the smpA loci of S. hyodysenteriae strains. Among seven strains of S. innocens, and the proposed species 'S. intermedius' and 'S. murdochii', hybridization was weak and no PCR products were obtained, suggesting that these species have sequences related to, but divergent from, the smpA sequences of strains of S. hyodysenteriae. Both gene probe hybridization and PCR analysis of nine strains of the proposed new genus 'Anguillina', including isolates from pigs and humans, gave negative results.

Animals↗
PubMed1995

Use of commercial enzyme kits and fatty acid production for the identification of Serpulina hyodysenteriae: a potential misdiagnosis.

The accuracy of identification of Serpulina hyodysenteriae strains grown in a complex medium was 90% when 2 commercial test kits were used. Unlike the other S. hyodysenteriae strains, S. hyodysenteriae strain P35/2 was unusual in being indole negative. The nonpathogenic intestinal spirochete PWS/A, which is from a different species, was indole positive and alpha-galactosidase negative. Identification of these spirochetes on the basis of these kits alone would have been incorrect. The analysis of volatile fatty acids by gas chromatography showed that the ratio of acetic to butyric acid was from 11:1 to 44:1 for S. hyodysenteriae strains, which distinguished them from the other spirochetes. The exception was PWS/A (acetic: butyric of 32:1), but this spirochete, unlike the S. hyodysenteriae spirochetes, also produced isobutyric acid. Short chain fatty acid (SCFA) analysis by high-performance liquid chromatography detected different SCFAs in addition to acetic and butyric acids. These additional SCFAs did not contribute to further differentiation of the porcine spirochetes.

Animals↗
PubMed1995

Comparative study of the enzyme activities of Borrelia burgdorferi and other non-intestinal and intestinal spirochaetes.

Comparative analysis of the enzymatic profiles of 58 spirochaetal isolates clearly differentiated borrelias from leptospires, serpulinas and a treponeme. Strains of both Borrelia burgdorferi and Borrelia hermsii characteristically produced significant amounts of leucine arylamidase. This enzyme activity was not unique to borrelias but was also detected amongst pathogenic and non-pathogenic leptospira serovars. This fact, however, did not hamper a correct differentiation of borrelias from these spirochaetes, because leptospires possessed unique enzyme profiles. The API ZYM system could not differentiate the human strains of B. burgdorferi from those isolated from ticks, or from B. hermsii. Treponema phagedenis could be differentiated from all the other spirochaetes by the production of alpha-fucosidase. Our results confirm and extend previous studies indicating that human and animal intestinal spirochaetes have many common enzyme activities. All strains produced reactions of maximum intensity when tested for the presence of beta-galactosidase activity. However the avian strains lacked esterase (C4) which was present in human and swine intestinal spirochaetes. All strains of Serpulina hyodysenteriae, and Serpulina innocens as well as the human intestinal spirochaete strain HRM-14 showed alpha and beta glucosidase activity. Both enzyme activities were absent or insignificant in most other intestinal spirochaetes examined: 25 different human strains, non-pathogenic swine strain M1 and the avian strain 4742. However, swine strain LL3 and avian strain 1380 showed some beta-glucosidase activity.

Animals↗
PubMed1994

Chemotactic response to mucin by Serpulina hyodysenteriae and other porcine spirochetes: potential role in intestinal colonization.

Chemotaxis of porcine spirochetes towards a variety of mucins was measured quantitatively by a capillary method. A chemotaxis buffer consisting of 0.01 M potassium phosphate buffer (pH 7.0) and 0.2 mM L-cysteine hydrochloride was necessary for chemotaxis of spirochetes. The optimum incubation time and incubation temperature were 1 h and 40 degrees C, respectively. The mucin concentration also affected the chemotaxis observed, and a concentration of 1% (wt/vol) was near the optimum. Virulent Serpulina hyodysenteriae strains were chemotactic towards 1% (wt/vol) hog gastric mucin and 1% (wt/vol) porcine colonic mucin but not towards 1% (wt/vol) bovine submaxillary mucin. Virulent S. hyodysenteriae strains were significantly more chemotactic than avirulent strains of S. hyodysenteriae (SA3 and VS1), Serpulina intermedius, and Serpulina innocens. Other spirochetes belonging to the proposed group of spirochetes Anguillina coli were also not chemotactic. Pathogenicity of S. hyodysenteriae strains that cause swine dysentery may, in part, be attributed to their attraction to porcine intestinal mucus.

Animals↗
PubMed1993

Molecular cloning, expression, and DNA sequence analysis of the gene that encodes the 16-kilodalton outer membrane lipoprotein of Serpulina hyodysenteriae.

The gene (smpA) that encodes the 16-kDa outer membrane lipoprotein of Serpulina hyodysenteriae was cloned in Escherichia coli, and its primary structure was determined by nucleotide sequencing. The putative open reading frame encodes a prolipoprotein of 16.8 kDa which in its fully acylated and cleaved form is 15.1 kDa. Analysis of the N-terminal amino acid sequence derived from the DNA sequence revealed the presence of a signal sequence and a putative acylation and signal peptidase II cleavage site (Phe-Ala-Val-Ser-Cys). In E. coli, processing of the prolipoprotein was less efficient than that observed in S. hyodysenteriae, and globomycin, an inhibitor of signal peptidase II, inhibited cleavage of the lipoprotein expressed in E. coli but did not inhibit cleavage in S. hyodysenteriae.

Amino Acid Sequence↗
PubMed1992

Monoclonal antibodies to a 16-kDa antigen of Serpulina (Treponema) hyodysenteriae.

Monoclonal antibodies (MAbs) were produced to an outer-envelope preparation from Serpulina (Treponema) hyodysenteriae, the aetiological agent of swine dysentery. Three MAbs (isotype IgG1) were obtained. All three recognised a 16-kDa antigen that was common to most strains of S. hyodysenteriae of different serotypes but was absent from nonpathogenic, porcine intestinal spirochaetes. Immunofluorescence and immunogold labelling studies showed that the 16-kDa antigen was exposed on the surface of intact spirochaetes. The MAbs agglutinated freshly grown cultures of spirochaetes and inhibited growth of S. hyodysenteriae strains in vitro.

Agglutination Tests↗
PubMed1992

A 16-kilodalton lipoprotein of the outer membrane of Serpulina (Treponema) hyodysenteriae.

Serpulina (Treponema) hyodysenteriae P18A and VS1 were extracted by using the detergent Triton X-114 and separated into detergent and aqueous phases. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western immunoblot analysis confirmed that a membrane-associated 16-kDa antigen was hydrophobic, since it was found in the detergent phase. A 45-kDa antigen partitioned into the aqueous phase, suggesting that it was hydrophilic and may be of periplasmic origin. When spirochetes were grown in the presence of [3H]palmitic acid, a predominant 16-kDa antigen was labeled; from the results of immunoprecipitation experiments, this antigen appeared to be the same as that recognized by both polyclonal and monoclonal antisera to a previously described 16-kDa antigen. This antigen was proteinase K sensitive and was not a component of the lipopolysaccharide, which, although [3H]palmitate labeled, was resistant to proteinase K digestion. The most probable explanation is that the 16-kDa antigen is a membrane-associated, surface-exposed, immunodominant lipoprotein.

Animals↗
PubMed1991

A cytotoxic haemolysin from Treponema hyodysenteriae--a probable virulence determinant in swine dysentery.

The haemolysin from a virulent strain of Treponema hyodysenteriae was extracted and injected into ligated loops of the ileum and colon of germ-free pigs. It caused severe epithelial damage, especially to the differentiated cells at the tips of the villi in the ileum and the cells in the intercrypt zones of the colon; goblet cells were less affected. The changes in the colon were similar to those seen in natural cases of swine dysentery. The ligated loop offers a means of investigating pathogenic mechanisms and the mode of action of the toxin. This study demonstrated that the haemolysin was a potent cytotoxin for pig enterocytes, and a probable virulence determinant in swine dysentery.

Animals↗
PubMed1989

Analysis of the axial filaments of Treponema hyodysenteriae by SDS-PAGE and immunoblotting.

Purified axial filaments from eight serotypes of Treponema hyodysenteriae and two non-pathogenic intestinal spirochaetes were characterized by SDS-PAGE and Western blotting. Axial filaments of all ten strains had similar SDS-PAGE profiles; five major axial filament polypeptides were identified, with molecular masses of 43.8, 38, 34.8, 32.8 and 29.4 kDa. Hyperimmune gnotobiotic pig serum raised against purified axial filaments of strain P18A (serotype 4) cross-reacted with all other serotypes and with the non-pathogens, and convalescent serum taken from a pig with persistent swine dysentery also showed a strong response to the axial filament polypeptides. Hyperimmune gnotobiotic pig serum raised against axial filaments failed to agglutinate viable organisms and did not inhibit growth in vitro. Hence, the axial filaments of T. hyodysenteriae have been identified as major immunodominant antigens, although the role that antibodies to these antigens play in protection has yet to be established.

Animals↗
PubMed1989

Antibodies to a common outer envelope antigen of Treponema hyodysenteriae with antibacterial activity.

Outer envelopes of Treponema hyodysenteriae strains P18A and VS1 were prepared and characterized by SDS-PAGE. In Western blot analysis of eleven strains of T. hyodysenteriae and two intestinal non-pathogenic spirochaetes, polyclonal antiserum raised to the outer envelopes of strain P18A contained antibodies primarily to two polypeptides. A 45 kDa polypeptide was present in only two strains of T. hyodysenteriae, P18A and MC52/80, whereas another antigen of 16 kDa was common to all eleven strains of T. hyodysenteriae but was not present in the two nonpathogens. Immunogold labelling of whole organisms suggested that the 16 kDa antigen was present on the surface of the spirochaetes. In in vitro tests the serum agglutinated and inhibited growth of only the T. hyodysenteriae strains, suggesting that antibodies to the 16 kDa antigen were responsible for these activities. Serum from a gnotobiotic pig infected with T. hyodysenteriae strain P18A had antibodies to the 16 kDa antigen alone and also possessed agglutinating and growth-inhibitory activities.

Antibodies, Bacterial↗
PubMed1986

In vivo properties of a cloned K88 adherence antigen determinant.

An Escherichia coli strain of serotype O9:K36:H19 harboring the K88 recombinant plasmid pMK005 was able to efficiently colonize the small bowel of young piglets after oral infection. The strain expressed K88 antigen in vivo, and bacteria were detected in close association with the surface of the intestinal villi. Mice infected orally or intravenously with attenuated Salmonella typhimurium SL3261 harboring pMK005 were well protected against subsequent challenge with the highly virulent S. typhimurium SL1344. Anti-K88 antibodies were detected in the serum of mice immunized with SL3261(pMK005).

Adhesins, Escherichia coli↗
PubMed1986

Emigration of polymorphonuclear leucocytes into the intestinal lumen of the neonatal piglet in response to challenge with K88-positive Escherichia coli.

The emigration of neutrophils from the blood of neonatal piglets into the intestinal lumen in response to a K88-positive strain of Escherichia coli was investigated. The pig herd used was of known genetic susceptibility to K88-positive E coli and had recently experienced an outbreak of neonatal diarrhoea. Neutrophil emigration depended on certain factors. Neutrophils emigrated into ligated loops in susceptible piglets sucking immune colostrum from susceptible dams but not into loops in colostrum deprived resistant piglets or piglets sucking non-immune colostrum from resistant dams. In susceptible, colostrum deprived piglets neutrophils in intestinal contents were only associated with severe lesions. Large numbers of neutrophils which appeared at several foci on the villi were observed in three of six resistant piglets that sucked immune colostrum from susceptible dams. It was concluded that neutrophil emigration into the intestinal lumen of piglets could occur in response to K88-positive E coli and resulted not from the presence or absence of the intestinal K88-receptor but from the ingestion of immune colostrum.

Animals↗
PubMed1984

Inhibition of adhesion of Escherichia coli K88 antigen by mammary secretions of susceptible and resistant sows.

Anti-adhesive activities of colostrum and milk from genetically susceptible sows, which protected their susceptible offspring in an outbreak of neonatal diarrhoea caused by K88-positive Escherichia coli, were compared with the activities in mammary secretions of resistant dams that did not protect their susceptible progeny. There was significantly more anti-adhesive antibody in the secretions of susceptible sows than in resistant sows, both during the disease period, and 1 year later. Fractionation of colostrum by gel filtration and ion-exchange chromatography led to identification of the anti-adhesive antibodies as including both IgA and IgM.

Animals↗
PubMed1983

Studies on the expression and organization of the K88ac adherence antigen.

The genetic determinant for the K88ac adhesion antigen has been cloned on a 6.5 kilobasepair DNA fragment into the multiple copy plasmid pBR322. The resulting hybrid plasmid named pMK005 was used to study the organization and expression of polypeptides involved in K88ac antigen assembly. Five cistrons named adh A, B, C, D and E were mapped on the cloned DNA and maximal expression of K88ac antigen was found to be dependent on a pBR322 encoded promoter. Four polypeptides of molecular weights 70,000 daltons, 25,000 daltons, 17,000 daltons, and 23,500 daltons (K88ac fimbrial subunit) were identified as the products of the adh A, B, C and D cistrons respectively. The subcellular location of each of these polypeptides was determined by fractioning minicells. pMK005 encodes sufficient information to promote adhesion of a wild-type E. coli strain 09:K13:H19 to the porcine small intestine in vivo.

Animals↗
PubMed1983

The effect of counselling on physical disability and social recovery after mastectomy.

A controlled trial was conducted to determine if a specialist nurse improved the physical and social recovery of patients after mastectomy and helped them adapt to the breast loss. Seventy five patients were counselled by the nurse who also monitored their progress after discharge while 77 patients received the care normally given by the surgical unit. Twelve to eighteen months after surgery those helped by the nurse showed a greater social recovery, return to work, adaptation to breast loss and satisfaction with their breast prostheses. Eleven percent remained distressed by the mastectomy but most responded well to breast reconstruction. The nurse had little impact on physical disability. The morbidity found in the control group highlights the need to find ways of reducing it. While the appointment of a specialist nurse can achieve this the morbidity would probably also be much reduced if the breast was conserved when possible, reliable staging methods other than axillary clearance were developed and the adverse effects of cytotoxic drugs and radiotherapy were reduced.

Adult↗