@article{MasotaVoggOhlsenetal.2021, author = {Masota, Nelson E. and Vogg, Gerd and Ohlsen, Knut and Holzgrabe, Ulrike}, title = {Reproducibility challenges in the search for antibacterial compounds from nature}, series = {PLoS One}, volume = {16}, journal = {PLoS One}, number = {7}, doi = {10.1371/journal.pone.0255437}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-260239}, year = {2021}, abstract = {Background Reproducibility of reported antibacterial activities of plant extracts has long remained questionable. Although plant-related factors should be well considered in serious pharmacognostic research, they are often not addressed in many research papers. Here we highlight the challenges in reproducing antibacterial activities of plant extracts. Methods Plants with reported antibacterial activities of interest were obtained from a literature review. Antibacterial activities against Escherichia coli and Klebsiella pneumoniae were tested using extracts' solutions in 10\% DMSO and acetone. Compositions of working solutions from both solvents were established using LC-MS analysis. Moreover, the availability of details likely to affect reproducibility was evaluated in articles which reported antibacterial activities of studied plants. Results Inhibition of bacterial growth at MIC of 256-1024 μg/mL was observed in only 15.4\% of identical plant species. These values were 4-16-fold higher than those reported earlier. Further, 18.2\% of related plant species had MICs of 128-256 μg/mL. Besides, 29.2\% and 95.8\% of the extracts were soluble to sparingly soluble in 10\% DMSO and acetone, respectively. Extracts' solutions in both solvents showed similar qualitative compositions, with differing quantities of corresponding phytochemicals. Details regarding seasons and growth state at collection were missing in 65\% and 95\% of evaluated articles, respectively. Likewise, solvents used to dissolve the extracts were lacking in 30\% of the articles, whereas 40\% of them used unidentified bacterial isolates. Conclusion Reproducibility of previously reported activities from plants' extracts is a multi-factorial aspect. Thus, collective approaches are necessary in addressing the highlighted challenges.}, language = {en} } @article{ArenasRoces2017, author = {Arenas, Andr{\´e}s and Roces, Flavio}, title = {Avoidance of plants unsuitable for the symbiotic fungus in leaf-cutting ants: Learning can take place entirely at the colony dump}, series = {PLoS ONE}, volume = {12}, journal = {PLoS ONE}, number = {3}, doi = {10.1371/journal.pone.0171388}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-157559}, pages = {e0171388}, year = {2017}, abstract = {Plants initially accepted by foraging leaf-cutting ants are later avoided if they prove unsuitable for their symbiotic fungus. Plant avoidance is mediated by the waste produced in the fungus garden soon after the incorporation of the unsuitable leaves, as foragers can learn plant odors and cues from the damaged fungus that are both present in the recently produced waste particles. We asked whether avoidance learning of plants unsuitable for the symbiotic fungus can take place entirely at the colony dump. In order to investigate whether cues available in the waste chamber induce plant avoidance in na{\"i}ve subcolonies, we exchanged the waste produced by subcolonies fed either fungicide-treated privet leaves or untreated leaves and measured the acceptance of untreated privet leaves before and after the exchange of waste. Second, we evaluated whether foragers could perceive the avoidance cues directly at the dump by quantifying the visits of labeled foragers to the waste chamber. Finally, we asked whether foragers learn to specifically avoid untreated leaves of a plant after a confinement over 3 hours in the dump of subcolonies that were previously fed fungicide-treated leaves of that species. After the exchange of the waste chambers, workers from subcolonies that had access to waste from fungicide-treated privet leaves learned to avoid that plant. One-third of the labeled foragers visited the dump. Furthermore, na{\"i}ve foragers learned to avoid a specific, previously unsuitable plant if exposed solely to cues of the dump during confinement. We suggest that cues at the dump enable foragers to predict the unsuitable effects of plants even if they had never been experienced in the fungus garden.}, language = {en} } @article{UteReisbergHildebrandtetal.2013, author = {Ute, Hentschel and Reisberg, Eva E. and Hildebrandt, Ulrich and Riederer, Markus}, title = {Distinct Phyllosphere Bacterial Communities on Arabidopsis Wax Mutant Leaves}, series = {PLoS ONE}, journal = {PLoS ONE}, doi = {10.1371/journal.pone.0078613}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-96699}, year = {2013}, abstract = {The phyllosphere of plants is inhabited by diverse microorganisms, however, the factors shaping their community composition are not fully elucidated. The plant cuticle represents the initial contact surface between microorganisms and the plant. We thus aimed to investigate whether mutations in the cuticular wax biosynthesis would affect the diversity of the phyllosphere microbiota. A set of four Arabidopsis thaliana eceriferum mutants (cer1, cer6, cer9, cer16) and their respective wild type (Landsberg erecta) were subjected to an outdoor growth period and analysed towards this purpose. The chemical distinctness of the mutant wax phenotypes was confirmed by gas chromatographic measurements. Next generation amplicon pyrosequencing of the bacterial communities showed distinct community patterns. This observation was supported by denaturing gradient gel electrophoresis experiments. Microbial community analyses revealed bacterial phylotypes that were ubiquitously present on all plant lines (termed "core" community) while others were positively or negatively affected by the wax mutant phenotype (termed "plant line-specific" community). We conclude from this study that plant cuticular wax composition can affect the community composition of phyllosphere bacteria.}, language = {en} }