title: Cold-adapted microorganisms as a source of new antimicrobials.
abstract: Thirty out of 8,000 different colony morphotypes isolated from soil samples of Isla de los Estados were selected based on their ability to produce antimicrobials. The significant influence of culture media and incubation temperature on antimicrobial production was proved, being LB medium and 8 degrees C the conditions of choice. Most of the psychrotolerant isolates were phylogenetically related to Serratia proteamaculans (96.4-97.9%) while the psychrophilic isolated 8H1 was closely related to Pseudomonas sp. (90-94% similarity). Produced antimicrobials showed a promising wide spectrum of activity both against gram-positive and gram-negative pathogenic bacteria. They were suspected to be microcin-like compounds (Mw <2,000 Da) and showed a marked tolerance to heat (1 h in boiling water bath) and pH-treatments (1-12). Antimicrobial compounds also showed to partially keep their activity even after overnight freezing at -20 and -80 degrees C and displayed a negative net charge at pH 8.0, a common feature of class II microcins.
authors.affiliation: PROIMI-CONICET, Av. Belgrano y Pje. Caseros, 4000 Tucumán, Argentina.
authors.forename: Leandro A
authors.initials: LA
authors.lastname: Sánchez
authors.forename: Fiorella F
authors.initials: FF
authors.lastname: Gómez
authors.forename: Osvaldo D
authors.initials: OD
authors.lastname: Delgado
mesh_terms: D000222:Adaptation, Physiological; D000890:Anti-Infective Agents / Q000378:metabolism* / Q000494:pharmacology; D001483:Base Sequence; D003080:Cold Temperature; D003470:Culture Media; D017931:DNA Primers; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008826:Microbial Sensitivity Tests; D010802:Phylogeny; D011549:Pseudomonas / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D012705:Serratia / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D012988:Soil Microbiology
chemical_list: D000890:Anti-Infective Agents; D003470:Culture Media; D017931:DNA Primers