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| Author(s): |
Fernanda Nogales da Costa Vasconcelos
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI) |
| Defense date: | 2014-06-09 |
| Examining board members: |
Beny Spira;
Regina Lúcia Baldini;
Andrea Balan Fernandes;
Rodrigo da Silva Galhardo;
Gabriel Padilla Maldonado
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| Advisor: | Beny Spira |
| Abstract | |
Chromobacterium violaceum is a free-living, mobile bacterium that inhabits water sources and soils of tropical and subtropical regions, where the phosphate concentration is low. The PHO regulon is activated in response to low phosphate concentration in the environment. Surprisingly, the growth yield of C. violaceum under phosphate excess or under phosphate limitation is very similar. Mutations in pstS, phoU, phoA1 and phoA2 genes were constructed. The expression of alklaine phosphatase was not affected by the phoU and pstS mutations, suggesting that these genes do not participate in the repression of the PHO regulon. However, the pstS mutant was deficient in the uptake of Pi. The phoA1 and phoA2 mutants presented each one a severe reduction in alkaline phosphatase activity. The hypothesis that PhoA1 and PhoA2 form a heterodimeric protein was investigated. Transcriptional fusions between the promoters of phoB and phoU to lacZ showed that these genes respond to Pi starvation. Stress resistance assays showed that C. violaceum is generally sensitive to environmental stresses. (AU) | |
| FAPESP's process: | 09/05265-7 - Characterization of regulon PHO genes and general stress responses in Chromobacterium violaceum |
| Grantee: | Fernanda Nogales da Costa Vasconcelos |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |