INVESTIGADORES
DELGADO Osvaldo Daniel
congresos y reuniones científicas
Título:
La lucha contra los patógenos no ha finalizado: expediciones en la Antártida Argentina revelan una nueva fuente para la bioprospección de antimicrobianos activos en frio.
Autor/es:
DANILOVICH M; ACOSTA F; SANCHEZ LA; DELGADO OD
Lugar:
Mar del Plata
Reunión:
Congreso; X Congreso de la Sociedad Argentina de Microbiologia; 2014
Institución organizadora:
Sociedad Argentina de Microbiologia General
Resumen:
An organism
that lives in an extreme environment is an extremophile. Within extremophiles
we can find organisms belonging to archaea, prokaryotes and eukaryotes. Key factors, such as frequent and
inappropriate use of antibiotic causing increase in bacterial resistance to
those commonly used, as well as an irregular emergence generated from a
detriment of pharmaceutical companies involved in drugs discovery, makes the
development of new antibiotics is a growing worldwide problem and a constant
challenge. The need to reduce additives in food industry has triggered the
pursuit of natural antimicrobial substances produced by microorganisms from
different sources with the aim of preserving processed foods by inhibiting
microorganisms associated with food-borne illness. Most antibiotics emerged
from screening programs of natural sources, including the isolation of new
microorganisms, modification of well-known producers or metabolic engineering
of fermentation processes. Extremophiles are considered an important source of metabolites, enzymes
and bio-products since they are adapted to their unusual living conditions. This work focused on the isolation of
psychrotolerant and psychrophilic microorganisms producing cold-active
substances with the ability to inhibit the growth of common food-borne
pathogens and phytopatogens for potential use in food preservation,
pharmaceutical industry or as agriceutical. Twenty-seven antimicrobial
producers were isolated by using microbiological selection techniques from sea
water and sediment samples obtained during the 2011 and 2014 summer Antarctic campaigns of the
oceanographic survey ship ARA Puerto Deseado. Isolates were grouped in 11 OTUs by ITS-ARDRA
techniques; four of them were selected for identification based on rDNA regions
sequence analysis together with the biochemical characterization. Isolates 2D,
5D and 6D were closely related to Halomonas titanicae (99.8, 98.9, 96.7% respectively), whilst
isolate 18SH was related to Candida sake (99%). Antimicrobials produced
by isolates 2D, 5D and 6D exhibited low molecular weight (<6,000 Da) and
inhibition spectrum against both, Gram (+) and Gram (-) pathogenic bacteria.
The antagonist compound produced by Candida sake 18SH showed a higher
molecular weight (˃12,000 Da) and a narrower spectrum of bacterial inhibition.
However, antagonistic activity against fungi causing rots in fruits was
detected. Due to its potential as plant pathogen biocontrol agent was selected
for further characterization. Studies indicate antimicrobial stability in
5.0-7.0 pH range and 4-45°C temperature range. Antimicrobial activity was
detected during early stationary growth phase retaining antimicrobial activity
at low temperatures. To purify the antimicrobial, a protocol involving
solid-phase C18 cartridges and HPLC was developed. This work highlights cold environments as a
suitable source of microorganisms with the ability to produce cold-active
biomolecules of biotechnological interest.