In vitro adhesion of an avian pathogenic Escherichia coli O78 strain to surfaces of the chicken intestinal tract and to ileal mucus

The role of fimbria in adherence of an avian pathogenic Escherichia coli (APEC) O78 strain 789 to chicken intestine was studied. Bacterial adhesion to tissue sections representing the regions within the chicken intestinal tract was determined by using immunohistochemical methods. E. coli 789 grown to express the type 1 fimbria adhered efficiently to the crop epithelium, to the lamina propria of intestinal villi, and to the apical surfaces of both the mature as well as the crypt-located enterocytes in intestinal villi, whereas no adhesion to mucus-producing goblet cells was detected. The adhesion was inhibited by mannoside and the role of type 1 fimbriae in the observed adhesion was confirmed with a recombinant strain expressing type 1 fimbriae genes cloned from E. coli and Salmonella enterica. E. coli 789 strain grown to favor AC/I fimbriae expression as well as the recombinant E. coli strain expressing the fac genes adhered to goblet cells but only poorly to the other epithelial sites. E. coli strain 789 as well as S. enterica serovar Typhimurium IR715 and S. enterica serovar Enteriditis TN2 strains were able to multiply in ileal mucus medium. The type 1 fimbria expressing bacteria adhered to the ileal mucus, whereas the AC/I fimbriated strains showed poor adherence to the mucus. The adhesion of E. coli 789 onto the crop epithelium and the follicle associated epithelium of the chicken ileum was efficiently inhibited by an adhesive strain ST1 of Lactobacillus crispatus isolated from chicken, whereas poor inhibition of E. coli adherence was observed with the weakly adhesive L. crispatus strain 134mi. The type 1 fimbriae may be important in colonization of the chicken intestine by APEC and Salmonella.     

Do inspection practices in organic agriculture serve organic values? A case study from Finland

In many European countries,organic agriculture has rapidly beentransformed from a farmers' movement to aninstitutionalized part of agricultural policy.In certification, compliance with publishedorganic standards is verified through annualinspections on farms. In Finland, the role ofadvice in organic inspections has been thesubject of debate. Two inspections are usedhere to show how the term organic was definedand what the role of advice in relation tocompliance was. Both compliance and advisorytypes of interaction between the inspector andthe farmer were identified along an axis from input substitution to system redesign. Thefindings illustrate the heterogeneity of theprocesses and definitions of the term organicin connection with inspections. System redesignwas less obvious in compliance than items ininspection documents suggest. The physicalsurroundings and the methods used affectinspection practices. Institutionalization isnot merely negative, but may also provideresources for system redesign. Whether adviceis part of a new and emerging way of enforcinginspections is considered. The findings suggestthat dialogue and negotiation are necessary inpromoting system redesign and in enhancing thedevelopmental functions of organicinspections.     

Mannose receptor-mediated regulation of serum glycoprotein homeostasis

Carbohydrates are thought to function as tags that mark circulatory glycoproteins for rapid clearance. To examine the role of the mannose receptor (MR) in glycoprotein clearance, we generated mice genetically deficient in MR. MR-/- mice were defective in clearing proteins bearing accessible mannose and N-acetylglucosamine residues and had elevated levels of eight different lysosomal hydrolases. Proteomic analysis of MR-/- and control mouse sera showed that an additional 4 out of 52 proteins identified were elevated in MR-/- serum. Each of these is up-regulated during inflammation and wound healing. Thus, MR appears to operate as an essential regulator of serum glycoprotein homeostasis.