Banca de QUALIFICAÇÃO: Isabel Cristina Cunha Ferreira

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : Isabel Cristina Cunha Ferreira
DATE: 23/02/2023
TIME: 10:00
LOCAL: Auditório Maristela
TITLE:

"TAXONOMIC AND FUNCTIONAL CHARACTERIZATION OF BACTERIAL STRAINS OBTAINED FROM THE USE OF ANTIMICROBIAL PEPTIDES AS A SELECTION MECHANISM."

KEY WORDS:

prospecting, bacterial strains, antibacterial activity

PAGES: 90
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

Antibiotic resistance developed by bacteria has been a growing threat to the effective treatment of infections caused by these microorganisms. There is therefore a need to discover new antibacterials to replace those that have become ineffective. The limitations of classical cultivation techniques and independent cultivation methods for prospecting microorganisms make it difficult to discover new antimicrobial-producing microorganisms. Thus, there is a need for advances in the search for new technologies aimed at obtaining antimicrobial-producing microorganisms and other activities of interest. The development of antimicrobials requires a series of steps, where the first is the discovery and characterization of microorganisms with biotechnological potential. Thus, this study is organized into two chapters, where the first describes the methodology for the prospection of bacterial strains with potential for the production of antimicrobial compounds, through the supernatant of Paenibacillus elgii and in the second, the strains obtained from the methodology proposed in the first and that obtained positive results in tests for antibacterial activity were characterized genotypically and phenotypically. Culture media were enriched with P. elggi culture supernatant which is rich in antimicrobial peptides. Soil samples were inoculated in these media in order to select only bacteria resistant to that supernatant and, therefore, with potential for the production of similar compounds. Bacterial strains obtained through this protocol were tested for their antibacterial ability. Once verified the antibacterial activity for Escherichia coli, Bacillus subtilis and Pseudomonas. aeruginosa, the strains were identified by Sanger sequencing of the 16S rRNA gene and characterized phenotypically and genotypically. The strains named B7 and C6 had their genomes sequenced at Illumina/Oxford Nanopore Technologies. The genome-based taxonomic classification showed that the closest lineage to B7 is Kitasatospora xanthocidica (dDDH 32.8-37.8% and ANI 86.86%) indicating that it may be a new species. As for C6, it was confirmed to be Methylobacterium radiotolerans (dDDH 90.3-94% and ANI 97.51%). Regarding the functional annotation of genomes, 49 gene clusters were detected for isolate B7 and 9 for C6. Among them, we highlight the NRPS cluster (nonribosomal peptide synthase), present in both isolates and the most abundant in B7. NRPS-type enzymes are responsible for the production of non-ribosomal peptides, many of them with antibacterial activity, such as pelgipeptins¸ derived from P.elgii. Also noteworthy are 4 clusters, in B7, linked to the production of lantipeptides, the same class of bacteriocins as elgicins, in P.elgii. The presence of such gene clusters may indicate the production of similar compounds between B7 and C6 and P.elgii lineages. The CAMPR4 platform for predicting antimicrobial peptides identified 59 predictions in B7 and 40 in C6, all with probability greater than 0.68 (scale from 0 to 1). The BAGEL4 platform recognized 8 regions involved in the biosynthesis of ribosomally synthesized and post-translationally modified peptides in B7. This study attested to the efficiency of using antimicrobial peptides for the selection of microorganisms with biotechnological potential.

BANKING MEMBERS:
Presidente - 2222088 - ELIANE FERREIRA NORONHA
Externo à Instituição - FABYANO ALVARES CARDOSO LOPES - UFT
Externa ao Programa - 2221665 - LIDIA MARIA PEPE DE MORAES
Interno - 2644635 - ROBERT NEIL GERARD MILLER