The influence of the region between residues 220 and 344 and beyond in Phrixotrix railroad worm luciferases green and red bioluminescence

To find the regions having a major influence on the bioluminescence spectra of railroad worm luciferases, we constructed new chimeric luciferases switching the fragments from residues 1-219 and from 220-545 between Phrixotrix viviani (PxvGR; λmax = 548 nm) green light-emitting luciferase and Phrixothrix hirtus (PxhRE; λmax = 623 nm) red light-emitting luciferases. The emission spectrum (λmax = 571 nm) and KM for luciferin in the chimera PxRE220GR (1-219, PxhRE; 220-545, PxvGR) suggested that the region above residue 220 of PxvGR had a major effect on the active site. However, switching the sequence between the residues 226-344 from PxvGR luciferase into PxhRE (PxREGRRE) luciferase resulted in red light emission (λmax = 603 nm), indicating that the region 220-344 by itself does not determine the emission spectrum. Furthermore, the sequence before residue 220 of the green-emitting luciferase is incompatible for light emission with the sequence above residue 220 of PxhRE. These results suggest that the fragments before and after residue 220, which correspond to distinct subdomains, may fold differently in the green- and red-emitting luciferases, affecting the active site conformation.

Efeito da ingestão crônica de álcool na progressão de periodontite induzida em ratos da linhagem Fischer-344

Objective: Understand the effect of chronic alcohol on the progression of periodontitis induced in Fischer-344 rats. Methods: For the study, 22 Fischer-344 rats, two months old were used, divided into groups: alcohol (n=8), ligature (n=7) and control (n=7). On the first day, the animals in the alcohol group were exposed to ingestion of a water solution containing 20% alcohol (size/size), up to day 90. After thirty days from the beginning of the experiment, the animals in the alcohol group and the ligature group were submitted to the placement of a silk thread around the right maxillary second molar. Nothing was performed on the left side, serving as control. All the groups were submitted to euthanasia 60 days after ligature placement. To assess the destruction of periodontitis, a radiographic exam was used to measure the destruction of bone height. Results: The results of the study showed that on the side in which periodontitis was induced, the group that ingested alcohol suffered an increase in destruction, with statistical differences when compared with the ligature and control groups and increased bone destruction in the ligature group when compared to control. Conclusion: Within the limitations of the study, it was concluded that chronic alcohol consumption by Fischer-344 rats led to greater progression of induced periodontitis.

Functional XPB/RAD25 redundancy in Arabidopsis genome: characterization of AtXPB2 and expression analysis

The xeroderma pigmentosum complementation group B (XPB) protein is involved in both DNA repair and transcription in human cells. It is a component of the transcription factor IIH (TFIIH) and is responsible for DNA helicase activity during nucleotide (nt) excision repair (NER). Its high evolutionary conservation has allowed identification of homologous proteins in different organisms, including plants. In contrast to other organisms, Arabidopsis thaliana harbors a duplication of the XPB orthologue (AtXPB1 and AtXPB2), and the proteins encoded by the duplicated genes are very similar (95% amino acid identity). Complementation assays in yeast rad25 mutant strains suggest the involvement of AtXPB2 in DNA repair, as already shown for AtXPB1, indicating that these proteins may be functionally redundant in the removal of DNA lesions in A. thaliana. Although both genes are expressed in a constitutive manner during the plant life cycle, Northern blot analyses suggest that light modulates the expression level of both XPB copies, and transcript levels increase during early stages of development. Considering the high similarity between AtXPB1 and AtXPB2 and that both of predicted proteins may act in DNA repair, it is possible that this duplication may confer more flexibility and resistance to DNA damaging agents in thale cress. (C) 2004 Elsevier B.V. All rights reserved.

Qualidade de frutos de cajá-manga armazenados sob diferentes temperaturas

O presente trabalho teve como objetivo determinar o efeito de diferentes temperaturas de armazenamento na qualidade de frutos de cajá-manga. Os frutos de cajá-manga foram obtidos junto ao CEAGESP - Companhia de Entrepostos e Armazéns Gerais de São Paulo, e transportados em caixas isotérmicas para o Laboratório onde foram selecionados quanto à aparência, estádio de maturação, ausência de danos físicos, depois sanitizados em solução de 50 ppm de cloro livre e acondicionados em bandejas de poliestireno expandido, envolto por filme de policloreto de vinila (PVC). O delineamento experimental utilizado foi o inteiramente casualizado, com três tratamentos (4ºC, 8ºC e 25ºC) e 5 épocas de avaliação (0; 3; 6; 9 e 12 dias após a instalação do experimento). em cada coleta, foram avaliadas a firmeza, a acidez titulável, os sólidos solúveis, o teor de ácido ascórbico, a cor da casca e, também, a liberação de CO2 pelos frutos ao longo do tempo. Foi observado que baixas temperaturas prolongam a vida útil dos frutos e que a temperatura de armazenamento influencia nas características avaliadas, sendo a temperatura de 8ºC a mais adequada para o armazenamento dos frutos de cajá-manga.

Viabilidade da inspeção traqueobrônquica, por videoendoscopia, em cães

Nesta pesquisa estudou-se a exeqüibilidade, um protocolo adequado e as vantagens e desvantagens da traqueobroncoscopia em cães. Foram utilizados 20 cães adultos, sendo 8 machos e 12 fêmeas, dos quais 50% apresentavam sinais clínicos de afecção respiratória. Para o exame foi utilizado um fibroscópio óptico flexível acoplado a uma vídeo-câmera. Na inspeção das vias respiratórias procurou-se detectar alterações macroscópicas compatíveis ou não com os dados fornecidos pelos exames físico, hematológico e auscultação. Todos os procedimentos foram bem sucedidos e os animais se recuperaram sem complicações.