INVESTIGADORES
DELGADO osvaldo Daniel
congresos y reuniones científicas
Título:
Recognition of active biomolecules with antimicrobial capacity produced by filamentous fungi in different culture media.
Autor/es:
VERGARA R; DELGADO OD; FARIÑA JI
Lugar:
Mar del Plata
Reunión:
Congreso; VIII Congreso de Microbiologia General; 2012
Institución organizadora:
Sociedad Argentina de Microbiologia General
Resumen:
Fungi
growing in natural environments, like many other microorganisms, are forced to
interact with surrounding organisms and the physicochemical characteristics of
the environment. As a consequence of these interactions, metabolites with
varied biological activities which play an important role in survival are
produced. Defensive bioactive compounds with varied structural identity, such
as antimicrobials, are thus synthesized to develop a natural competence tool.
In
this study, filamentous fungi were isolated from different samples collected
from Las Yungas rainforest (Tucumán), and their ability to produce
antimicrobials after cultivation in different culture media was evaluated.
These culture media included LB, Czapek-Dox, Czapek-malta, GMY and R2A. Antimicrobial
activity was tested according to a modification of the protocol proposed by Kekessy and Piguet (1970). Selected isolates
showed inhibition against the growth of Gram(+) and Gram(-) pathogen
microorganisms such as Salmonella enterica ser. Tiphymurium, Salmonella
enterica ser. Newport, Salmonella enterica ser. Enteritidis, E.
coli ATCC35218, Enterobacter
aerogenes, Enterobacter cloacae, Shigella sonnei, Enterococcus faecalis ATCC29212, Staphylococcus aureus ATCC 29213 and Staphylococcus epidermidis. Eight
fungal isolates were selected according to their outstanding capacity to
produce antimicrobials and their molecular identification through the analysis
of the 28S ADNr D1/D2 domain revealed their closest relationship with Lanatonectria, Trichoderma, Gibberella,
Hipocrea and Fusariun genera.
Results
varied according to the culture media evaluated. In carbon-source rich media or
media containing aminoacids, like LB or GMY, no significant antimicrobial
production was noted, or this capacity was importantly reduced. Antimicrobial
activity was variable according to the isolate and the test strain used. In Czapek-Malta
and R2A, antimicrobial production became increased with
respect to that produced in LB and GMY media, although it also exhibited
certain variability depending on the isolate and the pathogen indicator strain.
Meanwhile, poor or minimal culture media such as Czapek
revealed qualitative and quantitatively higher antimicrobial production, mainly
for two fungal isolates of the Hipocrea
and Fusarium genera. In accordance to these findings,
Czapek resulted as the most suitable culture medium for evaluating bioactive
antimicrobial production by fungal isolates.