Made available in DSpace on 2014-12-17T14:05:19Z (GMT). No. of bitstreams: 1 DelanneCSSF_TESE.pdf: 5733269 bytes, checksum: db8ba3b543c1bd1c178d56cb6e6335bb (MD5) Previous issue date: 2011-09-08 / The sequencing of the genome of Chromobacterium violaceum identified one single circular chromosome of 4.8 Mb, in which approximately 40% of the founded ORFs are classified as hypothetical conserved or hypothetical. Some genic regions of biotechnological and biological interest had been characterized, e. g., environmental detoxification and DNA repair genes, respectively. Given this fact, the aim of this work was to identify genes of C. violaceum related to stress response, as the ones involved with mechanisms of DNA repair and/or genomic integrity maintenance. For this, a genomic library of C. violaceum was built in Escherichia coli strain DH10B (RecA-), in which clones were tested to UVC resistance, resulting in five candidates clones. In the PLH6A clone were identified four ORFs (CV_3721 to 3724). Two ORFs, CV_3722 and CV_3724, were subcloned and a synergic complementation activity was observed. The occurrence of an operon was confirmed using cDNA from C. violaceum in a RT-PCR assay. Further, it was observed the induction of the operon after the treatment with UVC. Thus, this operon was related to the stress response in C. violaceum. The mutagenesis assay with rifampicin after the treatment with UVC light showed high frequency of mutagenicity for the ORF CV_3722 (Pol III ? subunit). In this way, we propose that the C. violaceum ? subunit can act in DH10B in the translesion synthesis using Pol IV in a RecA independent-manner pathway. In growth curve assays other four clones (PLE1G, PLE7B, PLE10B and PLE12H) were able to complement the function at the dose 5 J/m2 and in mutagenicity assays PLE7B, PLE10B and PLE12H showed frequencies of mutation with significant differences upon the control (DH10B), demonstrating that in some way they are involved with the stress response in C. violaceum. These clones appear to be interrelated, probably regulated by a messenger molecule (eg., nucleotide c-di-GMP) and/or global regulatory molecule (eg., ?S subunit of RNA polymerase).The results obtained contribute for a better genetic knowledge of this specie and its response mechanisms to environmental stress. / O seq?enciamento do genoma da esp?cie Chromobacterium violaceum identificou um cromossomo simples circular de 4.8 Mb, no qual aproximadamente 40% das ORFs encontradas s?o classificadas como hipot?ticas conservadas ou hipot?ticas. Algumas regi?es g?nicas de interesse biotecnol?gico e biol?gico v?m sendo caracterizadas, como por exemplo, genes de detoxifica??o ambiental e genes de reparo de DNA, respectivamente. Diante disso, o objetivo deste trabalho foi identificar genes de C. violaceum envolvidos com a resposta ao estresse, como por exemplo, mecanismos de reparo de DNA e/ou manuten??o da integridade gen?mica. Para tanto, foi constru?da uma biblioteca gen?mica de C. violaceum na cepa DH10B de Escherichia coli (RecA-), a qual foi testada para clones resistentes a UVC, resultando na sele??o de cinco clones candidatos. Foram identificadas quatro ORFs (CV_3721 a 3724) no clone PLH6A. Das quais, as ORFs CV_3722 e CV_3724, foram subclonadas e uma atividade sin?rgica de complementa??o foi observada. A ocorr?ncia de um operon foi confirmada usando cDNA de C. violaceum em ensaio de RT-PCR. Adicionalmente, foi observada a indu??o do operon ap?s tratamento com UVC, dessa forma, esse operon foi relacionado ? resposta ao estresse em C. violaceum. Ensaios de mutag?nese com rifampicina ap?s tratamento com luz UVC mostraram alta freq??ncia de mutagenicidade para a ORF CV_3722, subunidade ? da Polimerase III. Assim, propomos que esta subunidade de C. violaceum pode agir em DH10B na s?ntese transles?o utilizando Pol IV em uma via RecA independente. Em ensaios de viabilidade outros quatro clones (PLE1G, PLE7B, PLE10B e PLE12H) foram capazes de complementar a fun??o na dose de 5 J/m2. E em ensaios de mutagenicidade PLE7B, PLE10B e PLE12H apresentaram freq??ncias de muta??o com diferen?as significativas em rela??o ao controle (DH10B), demonstrando que de alguma forma eles est?o envolvidos na resposta ao estresse em C. violaceum. Estes clones parecem estar inter-relacionados, provavelmente, regulados por mol?cula mensageira (como o nucleot?deo c-di-GMP) e/ou mol?cula regulat?ria global (como a subunidade ?S da RNA Polimerase). Os resultados obtidos contribuem para um melhor conhecimento da gen?tica desta esp?cie e de seus mecanismos de resposta ao estresse ambiental. / 2020-01-01

With the obvious evolution and acceleration of smart grid, it is crucial for its success to rely on a solid transmission protocol among its peripherals due to its real time streaming. TCP is the well known traditional transport protocol used for a reliable transmission, and is a major player for smart grid. However, it lacks a fault tolerance transmission method that overcomes potential failures which may mitigate smart grid progress and in its turn decrease its reliability. We propose that smart grid operators utilize SCTP as the principle transport protocol for their smart grid communications, by using the two very significant characteristics offered by SCTP multi-homing and multi-streaming respectively. Thus, we argue that they can override two major obstacles caused by TCP Head of Line Blocking (HLB) and the inability of handling automatically two or more paths to a final destination. Although SCTP resembles TCP in many aspects, SCTP can definitely play a dominant role in many current and future applications due to its key features that do not exist in TCP. We have used ns2.34 simulator as the tool whom we relied on to investigate whether or not smart grid may benefit over TCP by the two SCTP features, and have analyzed the output of simulated results by using other analytical tools. As we obtain results, we argue that smart grid operators should rely on SCTP as a feasible transmission protocol instead of TCP.

With the obvious evolution and acceleration of smart grid, it is crucial for its success to rely on a solid transmission protocol among its peripherals due to its real time streaming. TCP is the well known traditional transport protocol used for a reliable transmission, and is a major player for smart grid. However, it lacks a fault tolerance transmission method that overcomes potential failures which may mitigate smart grid progress and in its turn decrease its reliability. We propose that smart grid operators utilize SCTP as the principle transport protocol for their smart grid communications, by using the two very significant characteristics offered by SCTP multi-homing and multi-streaming respectively. Thus, we argue that they can override two major obstacles caused by TCP Head of Line Blocking (HLB) and the inability of handling automatically two or more paths to a final destination. Although SCTP resembles TCP in many aspects, SCTP can definitely play a dominant role in many current and future applications due to its key features that do not exist in TCP. We have used ns2.34 simulator as the tool whom we relied on to investigate whether or not smart grid may benefit over TCP by the two SCTP features, and have analyzed the output of simulated results by using other analytical tools. As we obtain results, we argue that smart grid operators should rely on SCTP as a feasible transmission protocol instead of TCP.

With the obvious evolution and acceleration of smart grid, it is crucial for its success to rely on a solid transmission protocol among its peripherals due to its real time streaming. TCP is the well known traditional transport protocol used for a reliable transmission, and is a major player for smart grid. However, it lacks a fault tolerance transmission method that overcomes potential failures which may mitigate smart grid progress and in its turn decrease its reliability. We propose that smart grid operators utilize SCTP as the principle transport protocol for their smart grid communications, by using the two very significant characteristics offered by SCTP multi-homing and multi-streaming respectively. Thus, we argue that they can override two major obstacles caused by TCP Head of Line Blocking (HLB) and the inability of handling automatically two or more paths to a final destination. Although SCTP resembles TCP in many aspects, SCTP can definitely play a dominant role in many current and future applications due to its key features that do not exist in TCP. We have used ns2.34 simulator as the tool whom we relied on to investigate whether or not smart grid may benefit over TCP by the two SCTP features, and have analyzed the output of simulated results by using other analytical tools. As we obtain results, we argue that smart grid operators should rely on SCTP as a feasible transmission protocol instead of TCP.