ABSTRACT
Food-producing animals can harbor Escherichia coli strains with potential to cause diseases in humans. In this study, the presence of enteropathogenic E. coli (EPEC) was investigated in fecal samples from 130 healthy sheep (92 lambs and 38 adults) raised for meat in southern Brazil. EPEC was detected in 19.2% of the sheep examined, but only lambs were found to be positive. A total of 25 isolates was characterized and designated atypical EPEC (aEPEC) as tested negative for bfpA gene and BFP production. The presence of virulence markers linked to human disease as ehxA, paa, and IpfAO(113) was observed in 60%, 24%, and 88% of the isolates, respectively. Of the 11 serotypes identified, eight were described among human pathogenic strains, while three (O1:H8, O11:H21 and O125:H19) were not previously detected in aEPEC. Associations between intimin subtypes and phylogroups were observed, including eae-theta 2/A, eae-beta 1/B1, eae-alpha 2/B2 and eae-gamma 1/D. Although PFGE typing of 16 aEPEC isolates resulted in 14 unique pulsetypes suggesting a genetic diversity, specific clones were found to be distributed in some flocks. In conclusion, potentially pathogenic aEPEC strains are present in sheep raised for meat, particularly in lambs, which can better contribute to dissemination of these bacteria than adult animals
Subject(s)
Microbiology , BacteriologyABSTRACT
A broad-spectrum vaccine against disease caused by serogroup B of Neisseria meningitidis is still a challenge due to antigenic variability. In the present study outer membrane protein complexes and their components were analysed using non-denaturing 2D electrophoresis and identified using LC/MS-MS and MALDI-TOF. Outer membrane protein complexes were purified from both the wild-type strain H44/76 and their knock-out mutants lacking PorA, PorB, RmpM or FetA. The immune responses elicited by the whole outer membrane vesicles (OMV) and the purified complexes were analysed for bactericidal activity, antibody surface binding, antibody-mediated C3b/iC3b deposition, membrane attack complex (MAC) deposition and induction of opsonophagocytosis, both on the homologous and several heterologous strains. The main antigenic complexes found were homomeric, formed by the 60 kDa chaperonin (MSP63) or PorB, or heteromeric, formed by different combinations of PorA, PorB and/or RmpM. The lack of some of these proteins in the OMVs from the knock-out mutants did not affect significantly the immune responses analysed except MAC, which was significantly reduced in the anti-PorA- and anti-PorB- sera, and bactericidal activity, which was absent in the anti-PorA- serum. The sera against purified native complexes showed variable activities against the homologous strain, with greatest responses observed for anti-chaperonin and anti-PorA/PorB/RmpM sera. When tested against heterologous strains, the only anti-complex serum showing consistent responses was that against the 60 kDa chaperonin. The comparison of the responses elicited by the different sera suggests an important role of conformational epitopes, present only in native complexes, in the induction of more effective responses against N. meningitidis.
Subject(s)
Antibodies, Bacterial/blood , Antigens, Bacterial/immunology , Bacterial Outer Membrane Proteins/immunology , Meningococcal Vaccines/immunology , Neisseria meningitidis/immunology , Animals , Antibodies, Bacterial/immunology , Antigens, Bacterial/chemistry , Antigens, Bacterial/isolation & purification , Bacterial Outer Membrane Proteins/chemistry , Bacterial Outer Membrane Proteins/isolation & purification , Complement Membrane Attack Complex , Electrophoresis, Gel, Two-Dimensional , Epitopes/immunology , HL-60 Cells , Humans , Immune Sera , Immunization , Meningococcal Vaccines/administration & dosage , Mice , Mice, Inbred CBA , Mutation , Neisseria meningitidis/genetics , Neisseria meningitidis/metabolism , Phagocytosis , Protein ConformationABSTRACT
A number of studies have indicated that delinquent adolescents have characteristic value systems. However, most of these studies have adopted a "known-groups" design--that is, they have compared institutionalized delinquents and non-institutionalized adolescents, assuming those adolescents to be non-delinquent. Designs of this type do not distinguish effectively between the statistical effects of delinquency and of institutionalization. In this study, the authors investigated relationships between values and self-reported antisocial behavior in three adolescent groups: 435 school-attending boys, 529 school-attending girls, and 95 delinquent boys in juvenile rehabilitation centers or prisons. The results indicate that antisocial behavior is associated with hedonistic values and a lack of interest in conventional values and social values. These relationships cannot be explained by the institutionalization effects.
