Biogenesis of multilamellar bodies via autophagy.

Transfection of Mv1Lu mink lung type II alveolar cells with beta1-6-N-acetylglucosaminyl transferase V is associated with the expression of large lysosomal vacuoles, which are immunofluorescently labeled for the lysosomal glycoprotein lysosomal-associated membrane protein-2 and the beta1-6-branched N-glycan-specific lectin phaseolis vulgaris leucoagglutinin. By electron microscopy, the vacuoles present the morphology of multilamellar bodies (MLBs). Treatment of the cells with the lysosomal protease inhibitor leupeptin results in the progressive transformation of the MLBs into electron-dense autophagic vacuoles and eventual disappearance of MLBs after 4 d of treatment.

Biological and molecular differentiation between coronaviruses associated with neonatal calf diarrhoea and winter dysentery in adult cattle.

Cytopathic coronaviruses were isolated in HRT-18 cells from bloody faecal samples collected from cows in Québec dairy herds with classical winter dysentery (WD). The formation of polykaryons in the infected cell cultures was found to be dependent on the presence of trypsin in the medium. Virus identification was confirmed by indirect immunofluorescence and indirect protein A-gold immunoelectron microscopy using rabbit hyperimmune serum, as well as monoclonal antibodies directed against the spike (S) and hemagglutinin-esterase (HE) glycoproteins of the prototype Mebus strain of bovine coronavirus (BCV-Meb).

Immunolocalization of a mesenchymal antigen specific to the gastrointestinal tract.

Background: The aim of the present study was to localize, at the fine structural level, a protein found by indirect immunofluorescence to be associated with the mesenchymal tissue 1) closely applied to the intervillus epithelium before the formation of intestinal crypts in the mouse fetus and 2) around intestinal crypts during and after their formation.

Methods: We used a pre-embedding immunolabeling technique for extracellular matrix molecules, and a monoclonal antibody (Mab) directed against antigen MIM-1/130.

Results: Immunofluorescence disclosed the presence of antigen 1/130 in the connective tissue closely applied to the epithelium of the gallbladder, pyloric glands, and intestinal and colonic crypts in adult mice.

An intestinal secretory protein is found in most glands associated with the gastrointestinal tract: von Ebner's and salivary glands, gallbladder, and pancreas.

We have previously shown that monoclonal antibodies (MAb) prepared against the duodenal mucosa of 4-day-old mice disclosed the presence of two antigens associated with the formation of intestinal crypts. One of these, MIM-1/39, was found in the apical cytoplasm of undifferentiated epithelial crypt cells of the duodenum and colon. We report here the immunolocalization of MIM-1/39 in different glands associated with the gastrointestinal tract, using a polyclonal antibody produced against antigen MIM-1/39.

Developmental expression of two antigens associated with mouse intestinal crypts.

Two monoclonal antibodies were prepared against the duodenal mucosa of four-day-old mice (MIM-1/39 and MIM 1/130). The expression of the antigens was associated with the crypts of the small and large intestine in the fetus and adult. MIM-1/39 was present in epithelial cells of the intervillous areas in the small intestine at 17 and 18 days of gestation; afterwards its expression was detected only in crypt cells from birth to adulthood.

Development of esophageal epithelium in the fetal and neonatal mouse.

Development of the fetal mouse esophageal epithelium was followed using light microscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and radioautography. At 15 days of gestation in the cervical (C), mediastinal (M), and abdominal (A) segments of the esophagus, the epithelium was two or three cells thick, and only cells located in the basal (germinal) layer incorporated tritiated thymidine. Ciliated cells were sparse in all three segments.