[Experimental infection of calves and sheep with bovine Giardia isolates].

9 Giardia-free calves were artificially infected with 1.5-5.1 x 10(6) Giardia cysts originating from Swiss cattle ("bovine isolates"). In 4 of these animals the course of infection was examined. After prepatent periods of 7-8 days all calves excreted high numbers of Giardia cysts for 60-112 days. During patency on 44% of the examination days Giardia cysts and antigen could be detected simultaneously in faecal samples using the flotation method and a sandwich-ELISA, respectively. With the exception of light diarrhoea lasting only for some days at the beginning of patency no other symptoms occurred. Further 5 artificially infected calves were submitted to autopsy. Giardia trophozoites were detected in 4 calves in the jejunum and in 1 animal in the ileum (peroxidase-antiperoxidase method). All animals were simultaneously infected with Campylobacter spp. and/or Rota- and Corona-virus. Electronmicroscopically mucosal attachment sites of Giardia trophozoites had intact microvilli and enterocytes. In various parts of the intestine blunting and flattening of the villi and cellular infiltrations of the mucosa were present. These alterations in calves are generally associated with bacterial and/or viral infections of calves. A Swiss bovine Giardia cyst-isolate was transmitted to 4 Giardia-free conventionally maintained lambs which excreted Giardia cysts after prepatent periods of 10-21 days for 31-61 days

APC senses cell-cell contacts and moves to the nucleus upon their disruption

Fil: Brocardo, Mariana G. Instituto de Investigaciones Bioquímicas. Fundación Campomar; Argentina.Fil: Bianchini, Michele. Instituto de Investigaciones Bioquímicas. Fundación Campomar; Argentina.Fil: Radrizzani, Martín. ANLIS Dr.C.G.Malbrán. Centro Nacional de Genética Médica; Argentina.Fil: Reyes, Gloria B. Instituto de Investigaciones Bioquímicas. Fundación Campomar; Argentina.Fil: Dugour, Andrea V. Instituto de Investigaciones Bioquímicas. Fundación Campomar; Argentina.Fil: Taminelli, Guillermo L. Instituto de Investigaciones Bioquímicas. Fundación Campomar; Argentina.Fil: Gonzalez Solveyra, César. Instituto de Investigaciones Bioquímicas. Fundación Campomar; Argentina.Fil: Santa-Coloma, Tomás A. Instituto de Investigaciones Bioquímicas. Fundación Campomar; Argentina.The adenomatous polyposis coli (APC) tumor suppressor protein is involved in the Wnt/wingless pathway, modulating beta-catenin activity. We report the development of a highly specific, chemically synthesized oligobody (oligonucleotide-based synthetic antibody), directed against the N-terminal region of APC. Using this reagent, we found that within 16 h of disrupting HT-29 cell-cell contacts by harvesting cells with trypsin/EDTA treatment and replating, APC was translocated from the cytoplasm to the nucleus. Five days after plating the cells, when the cells had returned to their normal confluent phenotype and cell-cell contacts were reestablished, APC returned to the cytoplasm. These results suggest that APC functions as part of a "sensor" system, and responds to the loss of cell-cell contacts by moving to the nucleus, and returning to the cytoplasm when the contacts are fully restored