3 research outputs found
Fusaricidins, Polymyxins and Volatiles Produced by Paenibacillus polymyxa Strains DSM 32871 and M1
Paenibacilli are efficient producers of potent agents against bacterial and fungal pathogens,
which are of great interest both for therapeutic applications in medicine as well as in agrobiotechnology.
Lipopeptides produced by such organisms play a major role in their potential to inactivate
pathogens. In this work we investigated two lipopeptide complexes, the fusaricidins and the
polymyxins, produced by Paenibacillus polymyxa strains DSM 32871 and M1 by MALDI-TOF mass
spectrometry. The fusaricidins show potent antifungal activities and are distinguished by an unusual
variability. For strain DSM 32871 we identified numerous yet unknown variants mass spectrometrically.
DSM 32871 produces polymyxins of type E (colistins), while M1 forms polymyxins P. For both
strains, novel but not yet completely characterized polymyxin species were detected, which possibly
are glycosylated. These compounds may be of interest therapeutically, because polymyxins have
gained increasing attention as last-resort antibiotics against multiresistant pathogenic Gram-negative
bacteria. In addition, the volatilomes of DSM 32781 and M1 were investigated with a GC–MS approach
using different cultivation media. Production of volatile organic compounds (VOCs) was
strain and medium dependent. In particular, strain M1 manifested as an efficient VOC-producer that
exhibited formation of 25 volatiles in total. A characteristic feature of Paenibacilli is the formation of
volatile pyrazine derivatives.Peer Reviewe
Identification and characterization of 33 Bacillus cereus sensu lato isolates from agricultural fields from eleven widely distributed countries by whole genome sequencing
The phylogeny, identification, and characterization of 33 B. cereus sensu lato isolates originating from 17 agricultural soils from 11 countries were analyzed on the basis of whole genome sequencing. Phylogenetic analyses revealed all isolates are divided into six groups, which follows the generally accepted phylogenetic division of B. cereus sensu lato isolates. Four different identification methods resulted in a variation in the identity of the isolates, as none of the isolates were identified as the same species by all four methods-only the recent identification method proposed directly reflected the phylogeny of the isolates. This points to the importance of describing the basis and method used for the identification. The presence and percent identity of the protein product of 19 genes potentially involved in pathogenicity divided the 33 isolates into groups corresponding to phylogenetic division of the isolates. This suggests that different pathotypes exist and that it is possible to differentiate between them by comparing the percent identity of proteins potentially involved in pathogenicity. This also reveals that a basic link between phylogeny and pathogenicity is likely to exist. The geographical distribution of the isolates is not random: they are distributed in relation to their division into the six phylogenetic groups, which again relates to different ecotypes with different temperature growth ranges. This means that we find it easier to analyze and understand the results obtained from the 33 B. cereus sensu lato isolates in a phylogenetic, patho-type and ecotype-oriented context, than in a context based on uncertain identification at the species level