TY  - JOUR
A1  - Schielmann, Marta
A1  - Szweda, Piotr
A1  - Gucwa, Katarzyna
A1  - Kawczyński, Marcin
A1  - Milewska, Maria J.
A1  - Martynow, Dorota
A1  - Morschhäuser, Joachim
A1  - Milewski, Sławomir
T1  - Transport deficiency is the molecular basis of \(Candida\) \(albicans\) resistance to antifungal oligopeptides
JF  - Frontiers in Microbiology
N2  - Oligopeptides incorporating \(N3\)-(4-methoxyfumaroyl)-L-2,3-diaminopropanoic acid (FMDP), an inhibitor of glucosamine-6-phosphate synthase, exhibited growth inhibitory activity against \(Candida\) \(albicans\), with minimal inhibitory concentration values in the 0.05–50 μg mL\(^{-1}\) range. Uptake by the peptide permeases was found to be the main factor limiting an anticandidal activity of these compounds. Di- and tripeptide containing FMDP (F2 and F3) were transported by Ptr2p/Ptr22p peptide transporters (PTR) and FMDP-containing hexa-, hepta-, and undecapeptide (F6, F7, and F11) were taken up by the oligopeptide transporters (OPT) oligopeptide permeases, preferably by Opt2p/Opt3p. A phenotypic, apparent resistance of \(C. albicans\) to FMDP-oligopeptides transported by OPT permeases was triggered by the environmental factors, whereas resistance to those taken up by the PTR system had a genetic basis. Anticandidal activity of longer FMDP-oligopeptides was strongly diminished in minimal media containing easily assimilated ammonium sulfate or L-glutamine as the nitrogen source, both known to downregulate expression of the OPT genes. All FMDP-oligopeptides tested were more active at lower pH and this effect was slightly more remarkable for peptides F6, F7, and F11, compared to F2 and F3. Formation of isolated colonies was observed inside the growth inhibitory zones induced by F2 and F3 but not inside those induced by F6, F7, and F11. The vast majority (98%) of those colonies did not originate from truly resistant cells. The true resistance of 2% of isolates was due to the impaired transport of di- and to a lower extent, tripeptides. The resistant cells did not exhibit a lower expression of \(PTR2\), \(PTR22\), or \(OPT1–3\) genes, but mutations in the \(PTR2\) gene resulting in T422H, A320S, D119V, and A320S substitutions in the amino acid sequence of Ptr2p were found.
KW  - microbiology
KW  - Candida albicans
KW  - oligopeptides
KW  - resistance mechanism
KW  - permease
KW  - antifungals
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-173245
VL  - 8
ER  - 
TY  - JOUR
A1  - Krohn-Molt, Ines
A1  - Alawi, Malik
A1  - Förstner, Konrad U.
A1  - Wiegandt, Alena
A1  - Burkhardt, Lia
A1  - Indenbirken, Daniela
A1  - Thieß, Melanie
A1  - Grundhoff, Adam
A1  - Kehr, Julia
A1  - Tholey, Andreas
A1  - Streit, Wolfgang R.
T1  - Insights into microalga and bacteria interactions of selected phycosphere biofilms using metagenomic, transcriptomic, and proteomic approaches
JF  - Frontiers in Microbiology
N2  - Microalga are of high relevance for the global carbon cycling and it is well-known that they are associated with a microbiota. However, it remains unclear, if the associated microbiota, often found in phycosphere biofilms, is specific for the microalga strains and which role individual bacterial taxa play. Here we provide experimental evidence that \(Chlorella\) \(saccharophila\), \(Scenedesmus\) \(quadricauda\), and \(Micrasterias\) \(crux-melitensis\), maintained in strain collections, are associated with unique and specific microbial populations. Deep metagenome sequencing, binning approaches, secretome analyses in combination with RNA-Seq data implied fundamental differences in the gene expression profiles of the microbiota associated with the different microalga. Our metatranscriptome analyses indicates that the transcriptionally most active bacteria with respect to key genes commonly involved in plant–microbe interactions in the Chlorella (Trebouxiophyceae) and Scenedesmus (Chlorophyceae) strains belong to the phylum of the α-Proteobacteria. In contrast, in the Micrasterias (Zygnematophyceae) phycosphere biofilm bacteria affiliated with the phylum of the Bacteroidetes showed the highest gene expression rates. We furthermore show that effector molecules known from plant-microbe interactions as inducers for the innate immunity are already of relevance at this evolutionary early plant-microbiome level.
KW  - microbiology
KW  - microalga-bacteria interaction
KW  - phycosphere biofilm
KW  - metagenomics
KW  - metatranscriptomics
KW  - metaproteomics
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-173701
VL  - 2017
IS  - 8
ER  -