Heterogeneity of Staphylococcus pseudintermedius isolates from atopic and healthy dogs

Staphylococcus pseudintermedius is part of the normal canine flora but frequently causes pyoderma in canine atopic dermatitis (AD). This study aimed to determine whether particular S. pseudintermedius strains were associated with AD and/or pyoderma. Ninety‐six S. pseudintermedius isolates from the ear, nares, perineum and lesions of 21 atopic and 16 healthy dogs were lysed with proteinase K and digested with 40 U SmaI. Restriction products were separated using pulsed‐field gel electrophoresis (PFGE) with an Oxford S. aureus control and lambda‐ladder DNA concatomer markers. A dendrogram was constructed by the unweighted pair group method. All isolates showed a ≥56% similarity coefficient. Nine distinct PFGE clusters were identified, as follows: five from both atopic and healthy dogs; three from atopic dogs only; and one from healthy dogs only. Nine clusters were isolated from the nares, eight from the perineum, five from the ears and six from pyoderma lesions. There were no significant differences in the frequency of isolation from atopic or healthy skin, body sites or infected lesions for any of the clusters. Two of six healthy dogs and 18 of 20 atopic dogs with multiple isolates had closely related isolates (less than three band differences) at more than one sampling site. Isolates from pyoderma lesions were closely related to at least one mucosal isolate in 11 of 16 dogs. Staphylococcus pseudintermedius isolates appear to be heterogeneous, and colonization or infection of atopic skin was not associated with any particular strain or cluster of strains.     

仔猪产前的生长条件会影响其断奶后的生长

1产前的影响因素加拿大Alberta大学的George R Foxcroft博士在PIC 2007年座谈会上说,虽然产品的质量或产量是很多生产环节的核心问题,但养猪业应"停止追求仔猪的数量转而关注其质量"。     

Kinetics of substrate oxidation and hydrogen peroxide production by Mycoplasma mycoides subsp. mycoides Large Colony (LC) type and Mycoplasma mycoides subsp. capri

Mycoplasma mycoides subsp. mycoides Large Colony (LC) type is a pathogen of goats causing contagious agalactia and respiratory disease, found on all continents where small ruminants are kept. It shares close genetic characteristics with M. mycoides subsp. capri. Substrate oxidation by 22 strains of M. mycoides subsp. mycoides LC from nine countries was compared with that of eight strains of M. mycoides subsp. capri from five countries. There was considerable similarity in the substrates used, but substrate saturation coefficients (K_s) varied for different substrates. Substrate utilization patterns and K_s values did not (1) significantly differentiate the LC strains from each other, (2) show any correlation with geographical origin, or (3) distinguish the LC strains from the capri strains. These results support previous studies justifying the reclassification of these subspecies as a single species.     

An analysis of cellular proliferation, and synthesis of lymphokines and specific antibody in vitro by leucocytes from immunized cattle

The relationships between the production of lymphokines, cellular proliferation and antibody synthesis by immune bovine PBL in vitro was examined to identify the cellular reactions responsible for differences in the titres of serum antibodies in calves from selected sire lines and MHC Class I phenotypes. Leucocytes from 22 calves immunized with ovalbumin and DNP-BSA proliferated specifically in vitro in the presence of 1-10 micrograms/ml ovalbumin 7-28 days after the second vaccination. Significant correlations between the production of IL-2, IFN-gamma and maximum proliferation were observed for the total group. The quantity of specific antibody produced when PBL were incubated alone or with 10(-1)-10(-2) micrograms/ml ovalbumin was also correlated significantly with the maximum proliferation and the serum antibody titre between 7 and 14 days. Anti-ovalbumin IgG was also synthesized in MLRs where the quantity of antibody was significantly correlated with the magnitude of proliferation. The responses in vitro to DNP-BSA were too low to provide meaningful comparisons. The results indicate that at intervals during the period of increasing serum titres, events in the bovine antibody response in vivo can be replicated in vitro. In addition, assays for proliferation, IL-2 or gamma-IFN, or specific antibody can be used to assess the magnitude of the immune response in vivo in experimental groups of cattle. Significant sire line differences in the serological responses to ovalbumin were observed but DNP-BSA was a poorer antigen and differences in the responses to this antigen were not significant. However, the sire line differences in vivo were not reflected in vitro in proliferative and lymphokine assays; only the production of antibody in vitro was significantly correlated with the in vivo serum titre.