Competing signals drive telencephalon diversity.

The telencephalon is the most complex brain region, controlling communication, emotion, movement and memory. Its adult derivatives develop from the dorsal pallium and ventral subpallium. Despite knowledge of genes required in these territories, we do not understand how evolution has shaped telencephalon diversity. Here, using rock- and sand-dwelling cichlid fishes from Lake Malawi, we demonstrate that differences in strength and timing of opposing Hedgehog and Wingless signals establish evolutionary divergence in dorsal-ventral telencephalon patterning. Rock dwellers exhibit early, extensive Hedgehog activity in the ventral forebrain resulting in expression of foxg1 before dorsal Wingless signals, and a larger subpallium. Sand dwellers show rapid deployment of Wingless, later foxg1 expression and a larger pallium. Manipulation of the Hedgehog and Wingless pathways in cichlid and zebrafish embryos is sufficient to mimic differences between rock- versus sand-dweller brains. Our data suggest that competing ventral Hedgehog and dorsal Wingless signals mediate evolutionary diversification of the telencephalon.

Morphological and molecular characterization of the poxvirus BeAn 58058.

BeAn 58058 virus (BAV) was isolated from an Oryzomis rodent in Brazil. BAV was shown to be antigenically related to another poxvirus also isolated in Brazil, the Cotia virus, but it remained ungrouped. Electron microscopy revealed that BAV has a typical poxvirus morphology. The Hind III DNA profile of BAV genome was similar with that of VV WR and Lister, but some differences in the profile were detected. We have also detected the presence of genes homologous to vaccinia virus (VV WR) genes in the genome of BAV. Genes related to vaccinia thymidine kinase (TK) gene and vaccinia growth factor (VGF) gene were found. The patterns of TK and VGF mRNA transcripts described for vaccinia virus infected cells were observed in BAV infected cells. Nucleotide sequence of BAV VGF homologous gene was similar to VV WR VGF sequences. This similarity was further seen when cross-hybridization of total genomes of BAV and VV was done. Polypeptide synthesis of BAV and vaccinia in infected cells also showed similar profiles. The genetic data was used to construct a phylogenetic tree where BAV and VV were placed at the same cluster. Based on our findings we propose that BAV is a vaccinia virus variant.

Chicken carcasses as a source of Campylobacter jejuni in Belo Horizonte, Brazil.

The presence of Campylobacter jejuni was investigated in stool specimens from chicken meat workers and in ready-for-market chicken carcasses from one industrial and nine non industrial slaughters in Belo Horizonte. In the latter C. jejuni was isolated from 19 (38.0%) of the 50 chicken carcasses and from 2 (13.3%) of the stool specimens obtained from 15 chicken meat workers. In the industrial slaughter it was found in only 1 (2.0%) of the 50 chicken carcasses and it was not isolated from any of the 40 stool specimens. There was a significant difference between industrial and non industrial slaughter in regard to the frequency of C. jejuni isolation from carcasses (p = 0.000002), probably due to the low hygiene conditions present in non industrial slaughters. The results of antimicrobial susceptibility tests, SDS gel electrophoresis and biotyping of the strains isolated from stool specimens obtained from chicken meat workers were similar to those observed in strains isolated from chicken carcasses which suggest that chicken could be the source of C. jejuni for the workers and both, chicken and workers, could be implicated in the transmission of C. jejuni infection in Belo Horizonte.

[Research on enteropathogenic bacteria from children with acute diarrhea, in Belo Horizonte, MG]. / Pesquisa de bactérias enteropatogênicas em crianças com diarréia aguda, em Belo Horizonte, MG.

Enteropathogenic bacteria were searched in feces of 80 children with acute diarrhea from the lower social economical level, all of them younger than twenty seven months old, and without any antimicrobial therapy, in Belo Horizonte, MG, Brazil, from June 1981 to August 1982. The following enteropathogenic bacteria were isolated from 46 children: Shigella in 12 children (15.00%), enterotoxigenic Escherichia coli in 12 children (15.00%), classic enteropathogenic Escherichia coli in 9 children (11.25%), Salmonella in 6 children (7.50%). Association of enteropathogenic bacteria were found in 7 children (8.75%). Yersinia enterocolitica and invasive Escherichia coli were not isolated from any patient.

Marcadores de virulencia de Pseudomonas aeruginosa. I - Provas "in vitro" tipos piocinicos e atividade hemolitica. / Virulence markers of Pseudomonas aeruginosa. I. In vitro tests: pyocin type and hemolytic activity

A virulencia de 145 amostras de Pseudomonas aeruginosa, isoladas de quatro servicos do Hospital das Clinicas da UFMG, previamente tipificadas pela producao de piocina, foi investigada quanto a capacidade para produzir "hemolisina". Do Bercario, foram estudadas 57 amostras e 46 destas (80,7%), pertencentes a um mesmo tipo piocinico, apresentaram titulo hemolitico baixa, isto e, igual ou menor que 1:8, enquanto as outras, pertencentes a tipos diferentes, tiveram titulos que variaram de 1:32-1:256. Do Contro de Tratamento Intensivo (CTI), foram estudadas 28 amostras.Duas destas apresentaram titulo hemolitico intermediario (1:16) e os restantes (92,8%), cuja maioria pertence a um grupo nao tipavel pela producao de piocina, mostraram titulos altos. Da Clinica Cirurgica 17 amostras pertencentes a cinco tipos diferentes mostraram titulos variaveis. Da Clinica Urologica, 43 amostras, com predominancia de nao tipaveis, variam quanto a capacidade de produzir "hemolisina"

Marcadores de virulencia de Pseudomonas aeruginosa. II - Provas "in vitro": atividade hemolitica e sensibilidade ao cloreto de benzalconio (CB) / Virulence markers of Pseudomonas aeruginosa. II - In vitro tests: hemolytic activity and sensitivity to benzalkonium chloride

Virulencia de 145 de Pseudomonas aeruginosa, isoladas do Bercario, Centro de Tratamento Intensivo (CTI), Clinica Cirurgica e Urologica do Hospital do Clinicas da UFMG, previamente tipificadas pela producao de piocina e a determinacao da atividade hemolitica e a sensibilidade ao cloreto de benzalconio (CB) foram investigadas. De 59 amostras oriundas do Bercario, 89,4% apresentaram atividade hemolitica baixa, isto e, igual ou menor que 1:16 e 18,6% foram sensiveis ao CB. Das amostras isoladas do CTI, 92,8% forneceram titulos altos de "hemolisina" e 75% se mostraram sensiveis ao CB. Nas Clinicas Cirurgica e Urologica respectivamente 60% e 51,1% das amostras tiveram titulos de "hemolisina" maiores ou iguas a 1:32 e 60% e 76,7% foram sensiveis so CB. Os resultados da producao de "hemolisina" e da sensibilidade ao CB sao comparados com o tipo piocinico numa tentativa de se encontrar correlacao entre esse marcador epidemiologico e aqueles provaveis marcadores de virulencia

Marcadores de virulencia de Pseudomonas aeruginosa. III - Correlacao entre provas "in vivo" e "in vitro". / Virulence markers of Pseudomonas aeruginosa. III. Correlation between in vivo and in vitro tests

A virulencia de 12 amostras de Pseudomonas aeruginosa com baixa atividade hemolitica (< ou igual 1:4) e quatro amostras com altos titulos hemoliticos (l:512), procedentes de hospital (pacientes e meio ambiente) e estudada em camundongos convencionais e queimados. Os valores medios da DL 50, determinados para camundongos convencionais, foram 10(7,0) e 10(7,1), respectivamente, para amostras de baixa e alta atividade hemolitica, o que nao e estatisticamente significativo (p > 0,05). Os valores para camundongos queimados, encontrados para quatro amostras de titulo hemolitico 1:4 e quatro de titulo 1:512, sao respectivamente, 10(6,8) e 10(6,1), tambem nao sao significativos (p > 0,05). As amostras classificam-se atraves dos valores da DL 50, em amostras de alta, media e baixa virulencia, segundo criterio adotado por Klyhn & Gorrill