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Phenotypic diversity and potential virulence factors of the Shewanella putrefaciens group isolated from freshwater fish Texte intégral
2019
Paździor Ewa | Pękala-Safińska Agnieszka | Wasyl Dariusz
Phenotypic diversity and potential virulence factors of the Shewanella putrefaciens group isolated from freshwater fish Texte intégral
2019
Paździor Ewa | Pękala-Safińska Agnieszka | Wasyl Dariusz
The Shewanella putrefaciens group are ubiquitous microorganisms recently isolated from different freshwater fish species and causing serious health disorders. The purpose of the study was to characterise isolates of the S. putrefaciens group with special emphasis on elucidating serological diversity and determining putative virulence factors.
Afficher plus [+] Moins [-]Phenotypic diversity and potential virulence factors of the Shewanella putrefaciens group isolated from freshwater fish Texte intégral
2019
Paździor, Ewa | Pękala-Safińska, Agnieszka | Wasyl, Dariusz
The Shewanella putrefaciens group are ubiquitous microorganisms recently isolated from different freshwater fish species and causing serious health disorders. The purpose of the study was to characterise isolates of the S. putrefaciens group with special emphasis on elucidating serological diversity and determining putative virulence factors. Isolates collected from freshwater fish (n = 44) and reference strains were used. The identification of bacteria was carried out using biochemical kits and 16S rRNA sequencing. Polyclonal antibodies were prepared against the S. putrefaciens group. The bacterium’s susceptibility to antimicrobial agents, its enzymatic properties, and its adhesion ability to fish cell lines were also tested. Finally, selected isolates were used in challenge experiments in common carp and rainbow trout. Excluding six isolates undeterminable for species, the bacteria were classified to three species: S. putrefaciens, S. xiamenensis, and S. oneidensis, and showed some phenotypic diversity. Fourteen serological variants of the S. putrefaciens group were determined with the newly developed serotyping scheme. Serodiversity may play an important role in the virulence of particular isolates. Further, S. putrefaciens group members adhere to epithelial cells and produce enzymes which may contribute to their virulence. Challenge tests confirmed the pathogenicity of the S. putrefaciens group for fish.
Afficher plus [+] Moins [-]Different types of stainless steel used in equipment in meat plants do not affect the initial microbial transfer, including pathogens, from pork skin Texte intégral
2015
Lariviere-Gautheir, Guillaume | Quessy, Sylvain | Fournaise, Sylvain | Letellier, Ann | Fravalo, Philippe
This study describes and measures the impact of different compositions and finishes of stainless steel used in equipment in the meat industry on the transfer of natural flora and selected pathogens from artificially contaminated pork skin. It is known that the adhesion to surfaces of Listeria monocytogenes and Salmonella, 2 pathogens frequently found in contaminated pork meat, depends on the nature and roughness of the surface. Our results show no statistically significant differences in microbial transfer regardless of the types of stainless steel considered, with the highest measured transfer difference being 0.18 log colony-forming units (CFUs)/800 cm2. Moreover, no differences in total microbial community were observed after transfer on the 5 types of stainless steel using single-strand conformation polymorphism (SSCP). It was concluded that the different characteristics of the stainless steel tested did not affect the initial bacterial transfer in this study.
Afficher plus [+] Moins [-]EVALUATION OF EFFECTIVENESS OF CHITOSAN HYDROGEL AS HAEMOSTATIC FROM DORSAL NASAL VEINS IN RABBITS Texte intégral
2008
Bassim K.Khashjoori | Abdalbari A. Alfars
The haemostatic capability, adhesion ability and biocompatibility of chitosan sponges was compared with conventional method as control group. The chitosan sponges were briefly immersed in an aqueous 20% ammonia solution before being applied to a rabbit dorsal nasal vein wound. The total amount of bleeding from the injured veins until hemostasis was similar for both chitosan and control group. The complete hemostasis success rates for both the chitosan and control group were also similar. Under hemostasis, the chitosan sponges strongly adhered to the surface of the rabbit muscles, whereas the control group. Under wet conditions, however, there was no significant difference in the adhesive ability between the two groups. During implantation, the chitosan sponges were much more flexible and resistant to breakage that good. The biocompatibilities in addition, biodegradation rates of the Chitosan sponges were very different after subcutaneous implantation in rabbit.
Afficher plus [+] Moins [-]Resistance of Chinese Meishan, Fengjing, and Minzhu pigs to the K88ac+ strain of Escherichia coli
1994
Michaels, R.D. | Whipp, S.C. | Rothschild, M.F.
The microscopic brush border membrane adherence assay was used to determine resistance (nonadherence) and susceptibility adherence) of Chinese pigs (n = 289) to the K88ac+ strain of Escherichia coli-mediated disease. This study estimates prevalence of resistance to diarrheal disease in multiple family lines (no common ancestry for a minimum of 3 generations) for the Chinese Meishan, Fengjing, and Minzhu breeds. Results of in vitro assays indicate that pigs of the Meishan breed are highly resistant (nonadherent) to K88ac+ E coli-mediated disease. The gene conferring susceptibility to K88ac+ E coli-mediated disease exists at low frequency in pigs of the Minzhu breed. Minzhu-type (crossbred) pigs of both phenotypes (susceptible and resistant) were identified in ratios consistent with a 1-locus gene model. Given that all susceptible pigs were from 1 site, frequency of susceptibility within this Minzhu population is estimated at 8%. Inheritance within the Fengjing breed is still unclear because a weakly adherent phenotype, as well as the resistant phenotype, was identified. The weakly adherent phenotype was observed in pigs derived from multiple family lines. Expression of the weakly adherent phenotype in terms of susceptibility to disease is not known at this time.
Afficher plus [+] Moins [-]Use of polymerase chain reaction to detect porcine parvovirus associated with swine embryos
1994
Gradil, C.M. | Harding, M.J. | Lewis, K.
The role of porcine parvovirus (PPV) in inducing reproductive failure in swine has been extensively documented. However, information is not available as to the risk of ppv transmission by embryo transfer. Using the polymerase chain reaction (PCR) technique, PPV-specific DNA was detected in association with 4-day-old porcine embryos incubated in vitro in the presence of NADL-8 strain of PPV, despite attempts to rid the embryos of virus by either washing or treatment with pronase or trypsin. The presence of PPV in embryos collected from acutely infected swine was not detected by PCR, although PPV DNA was detected in the proximal portion of the reproductive tract during the early stages of infection. Viral-specific nucleic acid was not detected in embryos transferred from infected donors to seronegative recipients and retrieved and assayed on the 15th and 32nd days of gestation. Results of the use of PCR to detect PPV associated with swine female reproductive tract and embryos ascribe minimal risk to the transmission of PPV to seronegative recipients through embryo transfer.
Afficher plus [+] Moins [-]Adherence of streptococcal isolates from cattle and horses to their respective host epithelial cells
1988
Valentin-Weigand, P. | Chhatwal, G.S. | Blobel, H.
Adherence of Streptococcus dysgalactiae isolates from cattle and S equi isolates from horses to their respective host epithelial cells was compared with the adherence of S pyogenes to human epithelial cells. The adherence was quantitatively determined by use of fluorescein-labeled streptococci. All 3 streptococcal species adhered selectively to their respective host cells. The mechanism of adherence was evaluated by binding studies with adhesive plasma protein, fibronectin. Although all 3 streptococcal species bound fibronectin, S dysgalactiae and S equi interacted preferentially with a 210-kilodalton (kD) C-terminal fragment of fibronectin, whereas S pyogenes bound only a 29-kD N-terminal fragment. A synthetic peptide Gly-Arg-Gly-Asp-Ser, representing the host cell attachment site of fibronectin, partially inhibited the binding of fibronectin and of its 210 kD fragment to S dysgalactiae, but not to S equi. The binding of fibronectin and its 29-kD fragment to S pyogenes was not inhibited by Gly-Arg-Gly-Asp-Ser. These differences in binding activities corresponded to the ability of fibronectin to mediate the adherence of the streptococci to the epithelial cells: fibronectin strongly inhibited the adherence of S pyogenes and S equi to the epithelial cells, but only weakly inhibited that of S dysgalactiae.
Afficher plus [+] Moins [-]Effect of hyaluronic acid on prevention of adhesion in rats
Lee, J.H.;Lee, J.M.;Yun, Y.M.;Kang, T.Y.;Woo, H.C.;Kang, Y.H.;Kim, H.S.;Lee, K.K.;Cheong, J.T.(Cheju National University, Jeju, Republic of Korea)E-mail:cjt123@cheju.ac.kr | Kim, N.J.(HyeChon College, Daejeon, Republic of Korea)
This study was conducted to investigate the effect of hyaluronic acid (HA) on prevention of abdominal adhesions depending on various concentrations thereof by inducing an abrasion experimentally in the cecum of rats. Each group was consisted of 10 rats, and 40 rats were divided into 4 groups comprising the saline treatment group, HA 0.4% treated group, 0.6% treated group, and 0.8% treated group. And abrasion was caused in the cecum by using dry gauze and thereby, adhesion was induced. On 7 days after the operation, adhesions of each region were evaluated into the range of 0~4.
Afficher plus [+] Moins [-]Salmonella enterica serovar Typhimurium gene sseK3 is required for intracellular proliferation and virulence Texte intégral
2020
Du, Fuyu | Liao, Chengshui | Yang, Yadong | Yu, Chuan | Zhang, Xiaojie | Cheng, Xiangchao | Zhang, Chunjie
Salmonella enterica serovar Typhimurium (S. Typhimurium) is one of the most significant zoonotic pathogens that poses a threat to humans. Previous studies have identified that Salmonella-secreted effector K3 (SseK3) is a novel translated and secreted protein of S. Typhimurium. The objective of this study was to determine whether deletion of the sseK3 gene can attenuate the virulence of S. Typhimurium. To do this, we constructed an sseK3 deletion mutant using the double-exchange allele of the suicide plasmid pRE112ΔsseK3 and assessed the virulence and intracellular proliferation of the mutant. The sseK3 deletion mutant exhibited adhesion and invasion properties similar to those of wild-type (WT) S. Typhimurium, although the virulence and intracellular proliferation of the mutant were significantly reduced compared to that of the WT strain. Furthermore, the observed increase in the median lethal dose (LD(50)) reflects a decrease in the pathogenicity of the sseK3 deletion mutant in a murine model. In summary, we concluded that disruption of sseK3 can attenuate the intracellular proliferation and reduce the virulence of S. Typhimurium.
Afficher plus [+] Moins [-]Effect of coculture with stallion spermatozoa on de novo protein synthesis and secretion by equine oviduct epithelial cells
1995
Thomas, P.G.A. | Ignotz, G.G. | Ball, B.A. | Brinsko, S.P. | Currie, W.B.
Adhesion of equine spermatozoa to homologous oviduct epithelial cells (OEC) in vitro results in specific changes in spermatozoa and OEC function. To test the hypothesis that adhesion of spermatozoa affects protein synthesis and secretion by OEC, the following treatment groups were established in culture: OEC with culture medium only; control spermatozoa in culture medium only; OEC in coculture with spermatozoa; and OEC and spermatozoa in coculture, but physically separated by a microporous membrane. The experiment was replicated within each of 4 ejaculates from 3 stallions. De novo protein secretion by OEC was measured and compared by incorporation of [35S]methionine, and evaluated, using two-dimensional polyacrylamide gel electrophoresis and fluorography. Monolayers of OEC secreted a large number of proteins of molecular mass ranging from 14 to 205 kd. Adhesion of spermatozoa consistently caused reduced synthesis of 2 OEC secretory proteins and new or increased synthesis of 6 proteins. When spermatozoa and OEC were separated by a microporous membrane, some but not all of these changes were duplicated. Synthesis of 3 OEC secretory proteins, unaffected by binding of spermatozoa, was reduced when spermatozoa were prevented from contact with OEC by a microporous membrane. Adhesion of equine spermatozoa to homologous OEC monolayers and presence of equine spermatozoa resulted in qualitative and quantitative changes in synthesis and secretion of proteins by OEC. These changes have implications for storage, longevity, and maturation of spermatozoa.
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