Banca de DEFESA: Isabel Cristina Cunha Ferreira

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : Isabel Cristina Cunha Ferreira
DATE: 18/09/2023
TIME: 14:00
LOCAL: Meio virtual
TITLE:

TAXONOMIC AND FUNCTIONAL CHARACTERIZATION OF BACTERIAL STRAINS ISOLATED USING PAENIBACILLUS ELGII SUPERNATANT AS A SELECTION MECHANISM

KEY WORDS:

prospecting, supernatant, bacterial strains, antibacterial activity

PAGES: 218
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

This study evaluated the prospection of bacterial strains with potential for the production of antimicrobial compounds from the enrichment of culture media with the supernatant of Paenibacillus elgii, which is abundant in antimicrobial peptides and other signal molecules. Soil samples were inoculated in these media in order to select only bacterial strains resistant to that supernatant and, therefore, with potential for the production of similar compounds. The search for strategies aimed at obtaining strains with biotechnological potential is necessary due to the limitations of classic cultivation techniques in prospecting new species that produce antimicrobials. It is also known that the repertoire of bioactive compounds established for known microorganisms has not yet been fully unveiled. There is also concern that antibiotic resistance developed by some bacteria, a fact that has been a growing threat to the effective treatment of infections caused by these microorganisms. Therefore, there is a demand for the discovery of new antibacterials to replace those that have become ineffective. The development of antimicrobials requires a series of steps, the first of which is the discovery and characterization of potential producers. The bacterial strains obtained through this protocol were evaluated for their antibacterial activity against Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa and were previously identified by Sanger sequencing of the 16S rRNA molecular marker gene. All strains showed antibacterial activity for B. subtilis and E. coli and only two of them for P. aeruginosa. Analysis of the 16S rRNA showed that the selected strains belong to genera already known for their biotechnological potential. They are: Paenibacillus, Pseudomonas, Enterobacter, Kitasatospora, Sphingomonas, Xanthobacter, Burkholderia and Methylobacterium. Bacterial strains isolated and with antibacterial activity against P. aeruginosa were named K002 strain and K003 strain and had their genotypes and phenotypes characterized. Their genomes were sequenced on the Illumina and Oxford Nanopore Technologies platforms. The taxonomic classification based on genomes showed that the species closest to the K002 strain is Kitasatospora xanthocidica (dDDH 32.8-37.8% and ANI 86.86%) indicating that it may be a new species. The K003 strain was confirmed to be a Methylobacterium radiotolerans (dDDH 90.3-94% and ANI 97.51%). The functional annotation of the genomes indicated the presence of sixty biosynthetic gene clusters related to secondary metabolism for the K002 strain and ten for the K003 strain. Most of them can be related to the antimicrobial potential of the strains. The presence of certain biosynthetic gene clusters in common with P.elgii may indicate the production of similar compounds between it and the K002 and K003 strains selected from its supernatant. The methodology described in this work allowed the isolation of distinct bacterial genera. The results show that K002 and K003 strains harbor several genes responsible for the biosynthetic production of secondary metabolites confirming their potential as a valuable source of bioactive compounds. Thus, this study showed the efficiency of using P. elgii supernatant in selecting microorganisms with potential for biotechnological application. Furthermore, the fact that the K002 strain is a species not yet described may indicate that the methodology favors the isolation of new bacterial species.

COMMITTEE MEMBERS:
Externo à Instituição - Diogo Antonio Tschoeke - UFRJ
Interna - 2222088 - ELIANE FERREIRA NORONHA
Externo à Instituição - FABYANO ALVARES CARDOSO LOPES - UFT
Presidente - 1661623 - RICARDO HENRIQUE KRUGER
Interno - 2644635 - ROBERT NEIL GERARD MILLER