Banca de DEFESA: JULIANA DE FÁTIMA DOS SANTOS SILVA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : JULIANA DE FÁTIMA DOS SANTOS SILVA
DATA : 14/03/2022
HORA: 13:00
LOCAL: Defesa remota, via Google Meet
TÍTULO:

CHARACTERIZATION OF THE QUORUM SENSING (QS) MECHANISM IN Zymomonas mobilis IN RESPONSE TO THE TYPE 2 AUTO-INDUCER (AI-2)

PÁGINAS: 76
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
SUBÁREA: Biologia Molecular
RESUMO:

The Gram-negative bacterium Zymomonas mobilis has several characteristics that make it attractive for the industrial production of different bioproducts, including bioethanol. Genetic manipulation techniques were developed for this bacterium, which has been genetically modified and/or adapted to work in integrated bioprocessing systems, producing several products with high added value, in addition to incorporating alternative sources of carbon to its metabolic pathways. Thus, Z. mobilis has been seen as a microorganism of great potential for the bioconversion industry and a better understanding of the mechanisms used by it to control its gene expression can help in the development of new genetically manipulated strains, with high capacity of industrial production. Autoinducer 2 (or AI-2) is one of the molecules used by bacteria to trigger the Quorum Sensing (QS) response, which activates expression of genes involved in a series of alternative mechanisms, when cells reach high population densities (including bioluminescence, motility, biofilm formation, stress resistance, pathogenicity factors, among others). Contrary to most autoinducers, AI-2 can induce QS responses in both Gram-negative and Gram-positive bacteria and has been suggested to constitute a trans-specific system of bacterial communication, capable of affecting even bacteria that cannot produce this autoinducer. In this work, we demonstrate that the ethanologenic Gram-negative bacterium Zymomonas mobilis (a non-AI-2 producer) responds to exogenous AI-2 by modulating expression of genes involved in mechanisms typically associated with QS in other bacteria, such as motility, DNA repair and nitrogen fixation. Interestingly, the metabolism of AI-2-induced Z. mobilis cells seems to favor ethanol production over biomass accumulation, probably as an adaptation to the high-energy demand of N2 fixation. This opens the possibility of employing AI-2 during the industrial production of second-generation ethanol, as a way to boost N2 fixation by these bacteria, which could reduce costs associated with the use of nitrogen-based fertilizers, without compromising ethanol production.

MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1948411 - LUIZ ROBERTO NUNES
Membro Titular - Examinador(a) Interno ao Programa - 1674592 - TIAGO RODRIGUES
Membro Titular - Examinador(a) Interno ao Programa - 1227329 - CESAR AUGUSTO JOAO RIBEIRO
Membro Titular - Examinador(a) Externo à Instituição - BENY SPIRA - USP
Membro Titular - Examinador(a) Externo à Instituição - DENISE COSTA ARRUDA - UMC
Membro Suplente - Examinador(a) Externo à Instituição - ROSANA PUCCIA - UNIFESP
Membro Suplente - Examinador(a) Externo à Instituição - WAGNER ALVES DE SOUZA JÚDICE - UMC