Banca de DEFESA: HECTOR MAURICIO CASANOVA NAVARRO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : HECTOR MAURICIO CASANOVA NAVARRO
DATE: 07/12/2023
TIME: 14:00
LOCAL: online
TITLE:

Filamentous Fungi Associated with Coral Reefs in the Blue Amazon: Bioprospecting of Secondary Metabolites and Potential Biological Activities

KEY WORDS:

Antimicrobial activity, polyketides, chemodiversity, molecular taxonomy, Didymellaceae

PAGES: 1
BIG AREA: Ciências Biológicas
AREA: Microbiologia
SUMMARY:

Global changes have an impact on marine ecosystems, affecting corals and
their microbiota. The Brazilian coastal zone, spanning approximately 8,000 km,
is home to a variety of ecosystems and is often referred to as the blue Amazon.
Fungi, which represent about 1% (~1900) of the species described in this
group, are part of the microorganisms that constitute the microbiota of corals
and sponges. These marine fungi produce a range of natural products (NPs)
through unique biosynthetic pathways, exhibiting potential biological activities
and playing a role in host defense. The NPs of marine fungi have been
highlighted in the discovery of new antimicrobials against emerging pathogens.
This study aimed to bioprospect and characterize secondary metabolites with
biological activities from filamentous fungi originating from sponges and corals
in the blue Amazon. Traditional culture media and techniques based on the
activation of biosynthetic pathways were used to enhance the richness of
secondary metabolites (MSs) of fungi, which belong to the Microbial Diversity
and Biotechnology Laboratory (LDBM) - UFAL. Chemical analysis techniques
were employed to annotate the synthesized MSs and assess their
biotechnological potential in controlling emerging human pathogens. Seven
species were selected from the LDBM-UFAL mycotheque, including Aspergillus
ruber FMPV 02; Epicocum chloridis FMPV 05; Aspergillus sydowii FMPV 10;
Aspergillus flavus FMPV 11; Curvularia sp. FMPV 12; Penicillium pedernalense
FMS 066; Pyrenochaetopsis sp. FMS 104. Extracts obtained from the mycelium
and culture supernatant were evaluated. Two strains, E. chloridis FMPV 05 and
A. sydowii FMPV 10, exhibited antimicrobial activity against Candida albicans,
Cryptococcus neoformans, and Staphylococcus aureus bacteria. The extracts
and fractions of these two fungi contained several compounds, with
diketopiperazines Leu-Pro cycle (12.62%) and its isomer (21.15%), Phe-Val
cycle (6.22%) and Pro cycle -Phe (4.50%) standing out as potentially
responsible for the antimicrobial activity and control of pathogen virulence
factors. Using the one-strain-of-many-compounds (OSMAC) strategy, the
fungus A. sydowii FMPV 10 exhibited antimicrobial activity against C. albicans
and C. neoformans. A 95% difference was observed in the compounds
synthesized in the different media used, demonstrating that different cultivation
strategies enhance the production of MSs with varying chemical and biological
profiles. Marine filamentous fungi from the blue Amazon are a promising source
for obtaining natural products with biotechnological potential. The strains E.
chloridis FMPV 05 and A. sydowii FMPV 10 produced molecules with
antimicrobial activity against bacteria and fungi pathogenic to human health.
However, to understand the role of these microorganisms in marine
ecosystems, further studies are needed that include strategies and techniques
aimed at linking chemodiversity and functional roles in the marine environment.

COMMITTEE MEMBERS:
Presidente - 2024367 - MELISSA FONTES LANDELL
Interno(a) - 1639893 - CLAUDIO LUIS SANTOS SAMPAIO
Interno(a) - 1916144 - GILBERTO COSTA JUSTINO
Externo(a) ao Programa - 1369387 - JOAO XAVIER DE ARAUJO JUNIOR - UFALExterno(a) à Instituição - LUIZ HENRIQUE ROSA - UFMG
Externo(a) à Instituição - CECILIA VERÔNICA NUNEZ - INPA
Externo(a) à Instituição - ALEXANDRE JOSÉ MACEDO - UFRGS