Navegando por Assunto "Chromobacterium violaceum"

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Acesso aberto (Open Access)
Análise proteômica da resposta ao arsênio e do exoproteoma de Chromobacterium violaceum
(Universidade Federal do Pará, 2011-07-06) CIPRANDI, Alessandra; SILVA, Artur Luiz da Costa da; http://lattes.cnpq.br/7642043789034070
Chromobacterium violaceum is a Gram-negative beta-proteobacterium found in tropical ecosystems and it is an opportunistic pathogen for animals and humans. C. violaceum infection is associated with a high mortality rate, but little is known about the molecular basis of pathogenicity mechanisms. As an environmental microorganism, C. violaceum is exposed to diverse external conditions, which require great adaptability and effective protection systems. C. violaceum possesses an arsenic resistance operon arsRBC. Arsenic is a toxic metalloid associated with skin lesions, neurological diseases and cancer. The aim of this study was to investigate changes in protein pattern in presence of arsenite and characterize secreted proteins of C. violaceum ATCC 12472. The proteins from C. violaceum were analyzed by twodimensional electrophoresis and mass spectrometry. Proteomic analysis revealed that arsenite induces an increase of proteins involved in oxidative stress response, DNA repair and energetic metabolism. Among the secreted proteins were identified virulence factors (metallopeptidases, collagenase and toxins), transporters, and proteins involved in stress response and potentially useful. The results show novel insights into the adaptive response of C. violaceum.
Acesso aberto (Open Access)
Diversity of Chromobacterium violaceum isolates from aquatic environments of state of Pará, Brazilian Amazon
(2008-11) DALL'AGNOL, Leonardo Teixeira; MARTINS, Rosimar Neris; VALLINOTO, Antonio Carlos Rosário; RIBEIRO, Karla Tereza Silva
The present study intended to characterize the phenotypic and genetic diversity of Brazilian isolates of Chromobacterium violaceum from aquatic environments within the Amazon region. Nineteen isolates showed morphological properties of C. violaceum and the majority grew at 44°C. Low temperatures, in contrast, showed to be inhibitory to their growth, as eleven isolates did not grow at 10ºC and nine did not produce pigmentation, clearly indicating an inhibition of their metabolism. The largest variation among isolates was observed in the citrate test (Simmons), in which 12 isolates were positive, and in the oxidation/fermentation of sucrose, with six positives isolates. Chloramphenicol, gentamicin and sulfonamides efficiently inhibited bacterial growth. Amplified products of the recA gene were digested with HindII or PstI, which produced three or four restriction fragments patterns, respectively. The combined analysis arranged the isolates into six genospecies. The higher diversity observed in Belém (genotypes C, D, E and F) may be a consequence of intense human occupation, pollution of the aquatic environment or due to the higher diversity of the environments sampled in that region. In conclusion, a high level of genetic and phenotypic diversity was observed, and four new genospecies were described.
Acesso aberto (Open Access)
Exposure to an extremely low-frequency electromagnetic field only slightly modifies the proteome of Chromobacterium violaceum ATCC 12472
(2015-06) BARAÚNA, Rafael Azevedo; SANTOS, Agenor Valadares; GRAÇAS, Diego Assis das; SANTOS, Daniel Moreira dos; GHILARDI JUNIOR, Rubens; PIMENTA, Adriano Monteiro de Castro; CAREPO, Marta Sofia Peixe; SCHNEIDER, Maria Paula Cruz; SILVA, Artur Luiz da Costa da
Several studies of the physiological responses of different organisms exposed to extremely low-frequency electromagnetic fields (ELF-EMF) have been described. In this work, we report the minimal effects of in situ exposure to ELF-EMF on the global protein expression of Chromobacterium violaceum using a gel-based proteomic approach. The protein expression profile was only slightly altered, with five differentially expressed proteins detected in the exposed cultures; two of these proteins (DNA-binding stress protein, Dps, and alcohol dehydrogenase) were identified by MS/MS. The enhanced expression of Dps possibly helped to prevent physical damage to DNA. Although small, the changes in protein expression observed here were probably beneficial in helping the bacteria to adapt to the stress generated by the electromagnetic field.