O presente relato descreve os achados clínicos e anatomopatológicos de um caso de amiloidose renal em um cão macho de nove anos da raça Shar-Pei. O animal apresentava quadro clínico de esporotricose e de insuficiência renal e exames positivos para erlichiose e leishmaniose. No dia anterior ao óbito, o cão apresentou apatia, desidratação e anúria. À necropsia foram observados inúmeros pontos milimétricos esbranquiçados localizados no córtex renal e hepatização do lobo diafragmático esquerdo. O achado histológico mais importante foi deposição de material eosinofílico, amorfo e acelular localizado nos tufos glomerulares que se corou positivamente pelo vermelho congo (amilóide). Observaram-se nefrite supurada multifocal, espessamento da cápsula de Bowman e broncopneumonia supurada crônica, com fibrose intensa. A origem da amiloidose, no presente caso, poderia ser hereditária, assemelhando-se à amiloidose familiar descrita em cães da raça Shar-Pei, ou ser devida à inflamação supurada crônica e/ou leishmaniose.
No abstract
Klebsiella pneumoniae producing extended-spectrum β-lactamase (ESBL) cause severe life threatening infections resulting in considerable morbidity and mortality especially in neonatology ward. The aim of this study was to evaluate the epidemiology and resistance of 131 strains collected between 2007 and 2008 in neonatology and pediatric wards and to determine the mode of their epidemic spread. The isolates were identified, tested for antimicrobial susceptibility with the disk-diffusion on Mueller-Hinton agar. The type of ESBL was determined by polymerase chain reaction (PCR) followed by sequencing for CTX-M enzymes. The epidemiological relationships between epidemic strains were analysed by pulsedfield gel electrophoresis. In this study, antibiotic susceptibility testing showed resistance to all β-lactams except imipenem with a concomitant resistance to aminoglycosides, tetracycline and cotrimoxazole. Fluoroquinolones still have activity against strains. Characterization of β-lactamases encoding genes revealed that all strains have SHV β-lactamases. TEM-type and CTX-M-1 group were encoded, respectively, in 21 and 57% of ESBLs isolates. Among 84 strains tested by PFGE, 14 pulsotypes were identified. DNA sequencing of amplified CTX-M β-lactamase genes justified diffusion of CTX-M-15 between epidemic strains. In conclusion, this study revealed a high degree of clonal diversity of isolates and complexity of outbreaks that involve more than two epidemic pulsotypes and indicated that both clonal spread of epidemic strains and transfer of β-lactamases might contribute to epidemic dissemination of ESBL in neonatology ward.
Problem statement: Despite the structural and functional similarities between the nitrogenase that performs biological nitrogen fixation reaction and the Dark Protochlorphyllide Oxidoreductase (DPOR) that performs chlorophyll-biosynthesis, attempts to substitute nitrogenasecomponents with DPOR-components have hitherto failed. This investigation was undertaken to test if Chlamydomonas reinhardtii protochlorophyllide (Pchlide) reductase (ChlL) that shares some structural similarity with Nitrogenase Reductase (NifH) could complement the functions of NifH in biological nitrogen fixation of Azotobacter vinelandii. Approach: Genetic complementation studies were performed to test if the chlL gene and its mutants cloned under transcriptional control of nifH promoter (nifHp) in a broad-host range low copy plasmid pBG1380 could render a Nif + phenotype to NifHdeficient A. vinelandii strains. Results: Expression of ChlL could render Nif + phenotype to NifHdeficient A. vinelandii only in the absence of NifM, a nif-specific PPIase essential for biogenesis of NifH. The ChlL mutants Cys95Thr and Cys129Thr were unable to substitute for NifH. Thus, the conserved cysteine ligands of [4Fe-4S] cluster in ChlL are essential for successful substitution of NifH by ChlL. Since C-termini of NifH and ChlL demonstrated the least similarity and Pro258, a substrate for the PPIase activity of NifM, is located in the C-terminus of NifH, we posited that replacing the C-terminus of NifH with that of ChlL would render NifM-independence to NifH. The NifH-ChlL chimera could support the growth of NifH-and NifM-deficient A. vinelandii in nitrogen limiting conditions implying that it has acquired NifM-independence. Conclusion/Recommendations: Collectively, these observations suggest that NifM, an evolutionarily conserved nif-specific PPIase, could have contributed to the functional divergence of biological nitrogen fixation and photosynthesis during evolution by virtue of its ability to exert opposing effects on structurally similar substrates, ChlL and NifH.
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