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Previous issue date: 2012-09-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The Chromobacterium violaceum is a β-proteobacterium Gram-negative
widely found in tropical and subtropical regions, whose genome was sequenced
in 2003 showing great metabolic versatility and biotechnological and
pharmaceutical potential. Given the large number of ORFs related to iron
metabolism described in the genome of C. violaceum, the importance of this
metal for various biological processes and due to lack of data about the
consequences of excess of iron in free-living organisms, it is important to study
the response mechanism of this bacterium in a culture filled with iron. Previous
work showed that C. violaceum is resistant to high concentrations of this metal,
but has not yet been described the mechanism which is used to this survival.
Thus, to elucidate the response of C. violaceum cultured in high concentrations
of iron and expecting to obtain candidate genes for use in bioremediation
processes, this study used a shotgun proteomics approach and systems biology
to assess the response of C. violaceum grown in the presence and absence of
9 mM of iron. The analysis identified 531 proteins, being 71 exclusively
expressed by the bacteria grown in the presence of the metal and 100 just in
the control condition. The increase in expression of proteins related to the TCA
cycle possibly represents a metabolic reprogramming of the bacteria caused by
high concentration of iron in the medium. Moreover, we observed an increase in
the activity assay of superoxide dismutase and catalase as well as in Total
Antioxidant Activity assay, suggesting that the metal is inducing oxidative stress
in C. violaceum that increases the levels of violacein and antioxidant enzymes
to better adapt to the emerging conditions. Are also part of the adaptive
response changes in expression of proteins related to transport, including iron,
as well as an increased expression of proteins related to chemotaxis response,
which would lead the bacteria to change the direction of its movement away
from the metal. Systems Biology results, also suggest a metabolic
reprogramming with mechanisms coordinated by bottleneck proteins involved in
transcription (GreA), energy metabolism (Rpe and TpiA) and methylation
(AhcY) / A Chromobacterium violaceum ? uma β-proteobact?ria Gram-negativa
encontrada amplamente em regi?es tropicais e subtropicais, cujo genoma foi
sequenciado em 2003 mostrando grande versatilidade metab?lica e potencial
biotecnol?gico e farmac?utico. Dada ? grande quantidade de ORFs
relacionadas com o metabolismo de ferro descritas no genoma da C.
violaceum, a import?ncia deste metal para diversos processos biol?gicos e
devido ? car?ncia de dados a respeito das conseq??ncias do excesso do ferro
em organismos de vida livre, ? importante estudar o mecanismo de resposta
desta bact?ria em meio repleto com ferro. Trabalhos anteriores mostram que a
C. violaceum apresenta resist?ncia a grandes concentra??es desse metal,
embora ainda n?o tenha sido descrito qual mecanismo ? utilizado para esta
sobreviv?ncia. Assim, visando elucidar a resposta da C. violaceum cultivada
em alta concentra??o de ferro e esperando-se obter genes candidatos para
serem utilizados em processos de biorremedia??o, o presente trabalho utilizou
a abordagem de prote?mica em shotgun e Biologia de Sistemas para avaliar a
resposta de C. violaceum cultivada na presen?a e aus?ncia de 9 mM de ferro.
A an?lise identificou 531 prote?nas, sendo 71 expressas exclusivamente pela
bact?ria cultivada na presen?a do metal e 100 apenas na condi??o controle. O
aumento na express?o de prote?nas relacionadas com o ciclo do TCA
possivelmente representa uma reprograma??o metab?lica na bact?ria causada
pela grande concentra??o de ferro no meio. Al?m disso, foi observado um
aumento no ensaio de atividade das enzimas Super?xido dismutase e
Catalase, bem como no ensaio de Atividade Antioxidante Total, sugerindo que
o metal est? induzindo um quadro de estresse oxidativo em C. violaceum, que
passou a aumentar os n?veis de violace?na e enzimas antioxidantes para
melhor se adaptar ? condi??o emergente. Tamb?m faz parte da resposta
adaptativa a altera??o na express?o de prote?nas relacionados a transporte,
inclusive de ferro, e com a resposta quimiot?xica, o que levaria a bact?ria a
mudar a orienta??o de sua locomo??o afastando-se do metal. Os dados de
Biologia de Sistemas tamb?m sugerem uma reprograma??o metab?lica com
mecanismos coordenados por gargalos proteicos envolvidos com transcri??o
(GreA), metabolismo energ?tico (Rpe e TpiA) e metila??o (AhcY)
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/12595 |
| Date | 25 September 2012 |
| Creators | Lima, Daniel Chaves de |
| Contributors | CPF:32398336468, http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4781004Y8, Lima, Lucymara Fassarela Agnez, CPF:00297997750, http://lattes.cnpq.br/1083882171718362, Pirovani, Carlos Priminho, CPF:00171845765, http://lattes.cnpq.br/9615448923708075, Medeiros, S?lvia Regina Batistuzzo de |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Bioqu?mica, UFRN, BR, Bioqu?mica; Biologia Molecular |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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