ABSTRACT
beta-Catenin plays essential roles in cell adhesion, by associating with cadherins, and as a signaling molecule, by interacting with the Tcf/LEF-1 family of transcription factors. In order to study the protein-protein interactions of beta-catenin in living cells, we fused it to green fluorescent protein (GFP). GFP-beta-catenin was incorporated into cell junctions but also accumulated in the nucleus, where it formed rod-like structures. The carboxyl-terminal armadillo repeats of GFP-beta-catenin were sufficient for nuclear localization, but formation of rods required the armadillo repeats and sequences in both the amino- and the carboxyl-terminal domains. Rod formation was prevented by coexpression of N-cadherin, APC, and Tcf-4, which bind to the armadillo repeats of beta-catenin, but not by coexpression of alpha-catenin, although alpha-catenin expression did prevent accumulation of beta-catenin in the nucleus. Interestingly, when alpha-catenin, beta-catenin, and Tcf-4 were coexpressed they colocalized in the nucleus, and this correlated with a decrease in beta-catenin/Tcf-dependent transcriptional activity. These results indicate that binding of beta-catenin to Tcf-4 overrides the function of alpha-catenin to sequester beta-catenin in the cytoplasm and suggest that alpha-catenin can regulate beta-catenin signaling in the nucleus.
Subject(s)
Cytoskeletal Proteins/metabolism , Trans-Activators , Animals , COS Cells , Cell Nucleus/metabolism , Cytoskeletal Proteins/chemistry , Fluorescent Antibody Technique , Green Fluorescent Proteins , Luminescent Proteins , Recombinant Fusion Proteins , TCF Transcription Factors , Transcription Factor 7-Like 2 Protein , Transcription Factors/metabolism , alpha Catenin , beta CateninABSTRACT
Complementary oligonucleotide probes specific for the human pro-opiomelanocortin (POMC) mRNA were used to analyze the expression of POMC gene in 56 human postmortem pituitaries by in situ hybridization histochemistry. POMC transcripts were visualized by autoradiography in anterior lobe of the pituitary where their distribution was in a 'patchy-like' pattern. No hybridization could be observed in the posterior lobe of the pituitary. We examined pituitaries from several controls and from patients dying with schizophrenia, Parkinson's disease. Alzheimer's disease, Wernicke's encephalopathy and depressive illness. Computer-assisted microdensitometric semiquantification of POMC mRNA using a complementary oligonucleotide as hybridization standard, revealed no statistically significant effect of postmortem delay (between 2.5 and 66 h), of gender, age (between 22 and 103) or cause of death in 56 human pituitary glands. A large variation in POMC levels was already observed among all 30 control cases. The levels of POMC mRNA observed in pituitaries from different pathologies did not show a significant variation when compared with control cases.
Subject(s)
Gene Expression , Pituitary Gland/metabolism , Pro-Opiomelanocortin/genetics , RNA, Messenger/genetics , Adult , Aged , Aged, 80 and over , Aging , Blotting, Northern , Female , Humans , Male , Middle Aged , Nucleic Acid Hybridization , Oligonucleotide Probes , Pituitary Gland/growth & development , Pituitary Gland/pathology , Postmortem Changes , RNA/genetics , RNA/isolation & purificationSubject(s)
Campylobacter Infections/microbiology , Campylobacter fetus/isolation & purification , Diarrhea, Infantile/microbiology , Feces/microbiology , Child , Child, Preschool , Diarrhea, Infantile/etiology , Enterobacteriaceae/isolation & purification , Enterobacteriaceae Infections/microbiology , Humans , Infant , Infant, Newborn , Microbial Sensitivity TestsABSTRACT
Se estudiaron 2.690 muestras provenientes de ninos enfermos para el aislamiento de Campylobacter fetus subsp. jejuni y otros patogenos entericos. Se identificaron 18 cepas de Campylobacter fetus subsp. jejuni lo que se correspondio con el 6,38% del total de patogenos identificados y con el 0,67% del total de casos estudiados.Las 18 cepas estudiadas fueron en un 100% resistentes a la penicilina, ampicillin, novobiocina, metacillin, oxacillin y colymicin mientras que todos fueron sensibles a la eritromicina, estreptomicina y acido nalidixico. Se correspondio con los meses de invierno el mayor por ciento de aislamiento. En ninguno de los casos estudiados coincidio el Campylobacter fetus subsp.jejuni con otra bacteria enterica patogena Entre los otros patogenos entericos buscados en estas muestras hubo predominio de la Escherichia coli enteropatogena. No se aislaron Yersinia enterocolitica ni Escherichia coli enteroinvasivo
Subject(s)
Humans , Campylobacter fetus , Culture Media , FecesABSTRACT
Nineteen Campylobacter jejuni strains survived best in suspensions with approximately 10(9) bacteria in 4% albumin solution at-60 degrees C for 17 months (18 out of 19). At the same temperature and during the same period they survived less well in milk (11 out of 19). Recovery of campylobacters after 7 weeks was abundant in albumin, and somewhat less in milk. At -20 degrees C survival in milk was worse; 17 out of 19 cultures did not survive 5 weeks in milk and 7 died in albumin. At 4 degrees C all but one strain survived two weeks in milk and none died in albumin, but after 3 weeks only 7 survived in milk and 2 in albumin. At room temperature campylobacters did not survive 10 days in any of the media used. Peptone water (4%) and peptone-saline proved unsuitable for preservation. From 20 positive stool samples kept at 4 degrees C, on the day after the first sampling C. jejuni could not be recovered from 10 samples; bacteria survived for 2-7 days in 8 samples, for 12-20 days in 2 samples.
