Banca de QUALIFICAÇÃO: AMANDA DE LIMA SILVA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : AMANDA DE LIMA SILVA
DATE: 14/12/2023
TIME: 10:00
LOCAL: Mini-auditório do ISCO - Sala 212
TITLE:

CHEMICAL CHARACTERIZATION AND BIOLOGICAL ACTIVITY OF COMPOUNDS OBTAINED FROM Streptomyces sp. ISOLATED FROM FLOWLAND SOIL IN THE AMAZON

KEY WORDS:

Amazon. Streptomyces. Floodplain. Antimicrobials. Antitumor.

PAGES: 39
BIG AREA: Ciências Biológicas
AREA: Microbiologia
SUBÁREA: Microbiologia Aplicada
SPECIALTY: Microbiologia Industrial e de Fermentação
SUMMARY:

The use of antibiotics in medicine, since the discovery of penicillin in the 20th century, has
been crucial in saving millions of lives. However, the extensive use of these drugs in the
treatment of infectious diseases has led to the emergence of resistant bacterial strains, posing a
significant challenge to public health. Resistance to treatments is not limited to antibiotic
therapy alone; cancer treatment presents similar challenges. In this context, the search for new
antimicrobial and anticancer agents from natural sources, such as actinobacteria, is necessary.
Actinobacteria, especially the genus Streptomyces, are known for their ability to produce
bioactive compounds, including antibiotics and antitumor agents. This study focuses on the
Amazonian floodplain soils, exploring microbial diversity, particularly actinobacteria, as
valuable sources of bioactive compounds. The objective is to isolate, characterize, and identify
floodplain soil strains from the Amazon, and to elucidate the chemical compounds originating
from their secondary metabolism. Actinobacteria were isolated from a serial dilution of a 10g
sample of floodplain soil. They were characterized macro and micromorphologically,
molecularly identified, and tests were conducted for the production of the following
metabolites: biotechnologically relevant enzymes, through culture media containing inducing
substrates; antibiotic molecules, using the agar well diffusion method against 15 clinically
relevant pathogens; anticancer activity through cytotoxicity studies against cancer cells.
Subsequently, an ethyl acetate extract of the isolated strains was prepared and analyzed by
HPLC and GC-MS. Five strains of actinobacteria were isolated, with mycelium colors ranging
from white to gray, and one of them producing a wine-colored pigment. All strains were
identified as Streptomyces sp., and all showed enzyme production. Streptomyces sp. VAR1,
VAR2, VAR4, and VAR5 showed positive results in antagonism tests, with VAR2 standing
out by producing an 18mm inhibition halo against Aeromonas hydrophyla. Chromatographic
analyses revealed the presence of various classes of compounds, and GC-MS of the ethyl
acetate extract from Streptomyces sp. VAR5 showed the predominant presence of 9,12-
Octadecadienoic acid (Z,Z)-, an important antimicrobial fatty acid. Preliminarily, it can be
concluded that Streptomyces sp. isolated from Amazonian floodplain soil may serve as a new
library for elucidating novel compounds with anticancer and antimicrobial activity.

COMMITTEE MEMBERS:
Presidente - 1833953 - SILVIA KATRINE RABELO DA SILVA
Interno - 1243405 - THALIS FERREIRA DOS SANTOS
Externa à Instituição - SARA FREITAS DE SOUSA RAMOS