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153 Publications visible to you, out of a total of 153
Photocontrolled Release of Chemicals from Nano- and Microparticle Containers.

Abstract (Expand)

A benzoin-derived diol linker was synthesized and used to generate biocompatible polyesters that can be fully decomposed on demand upon UV irradiation. Extensive structural optimization of the linker … unit was performed to enable the defined encapsulation of diverse organic compounds in the polymeric structures and allow for a well-controllable polymer cleavage process. Selective tracking of the release kinetics of encapsulated model compounds from the polymeric nano- and microparticle containers was performed by confocal laser scanning microscopy in a proof-of-principle study. The physicochemical properties of the incorporated and released model compounds ranged from fully hydrophilic to fully hydrophobic. The demonstrated biocompatibility of the utilized polyesters and degradation products enables their use in advanced applications, for example, for the smart packaging of UV-sensitive pharmaceuticals, nutritional components, or even in the area of spatially selective self-healing processes.

Authors: C. Englert, I. Nischang, C. Bader, P. Borchers, J. Alex, M. Prohl, M. Hentschel, M. Hartlieb, A. Traeger, G. Pohnert, S. Schubert, M. Gottschaldt, U. S. Schubert

Date Published: No date defined

Publication Type: Not specified

Piriformospora indica Reprograms Gene Expression in Arabidopsis Phosphate Metabolism Mutants But Does Not Compensate for Phosphate Limitation.

Abstract (Expand)

Piriformospora indica is an endophytic fungus of Sebacinaceae which colonizes the roots of many plant species and confers benefits to the hosts. We demonstrate that approximately 75% of the genes, which … respond to P. indica in Arabidopsis roots, differ among seedlings grown on normal phosphate (Pi) or Pi limitation conditions, and among wild-type and the wrky6 mutant impaired in the regulation of the Pi metabolism. Mapman analyses suggest that the fungus activates different signaling, transport, metabolic and developmental programs in the roots of wild-type and wrky6 seedlings under normal and low Pi conditions. Under low Pi, P. indica promotes growth and Pi uptake of wild-type seedlings, and the stimulatory effects are identical for mutants impaired in the PHOSPHATE TRANSPORTERS1;1, -1;2 and -1;4. The data suggest that the fungus does not stimulate Pi uptake, but adapts the expression profiles to Pi limitation in Pi metabolism mutants.

Authors: M. Bakshi, I. Sherameti, D. Meichsner, J. Thurich, A. Varma, A. K. Johri, K. W. Yeh, R. Oelmuller

Date Published: 28th Jul 2017

Publication Type: Not specified

Plant pathogenic anaerobic bacteria use aromatic polyketides to access aerobic territory

Abstract (Expand)

Around 25% of vegetable food is lost worldwide because of infectious plant diseases, including microbe-induced decay of harvested crops. In wet seasons and under humid storage conditions, potato tubers … are readily infected and decomposed by anaerobic bacteria (Clostridium puniceum). We found that these anaerobic plant pathogens harbor a gene locus (type II polyketide synthase) to produce unusual polyketide metabolites (clostrubins) with dual functions. The clostrubins, which act as antibiotics against other microbial plant pathogens, enable the anaerobic bacteria to survive an oxygen-rich plant environment.

Authors: G. Shabuer, K. Ishida, S. J. Pidot, M. Roth, H. M. Dahse,

Date Published: 7th Nov 2015

Publication Type: Not specified

Plant-like biosynthesis of isoquinoline alkaloids in Aspergillus fumigatus

Abstract (Expand)

Natural product discovery efforts have focused primarily on microbial biosynthetic gene clusters (BGCs) containing large multimodular polyketide synthases and nonribosomal peptide synthetases; however, … sequencing of fungal genomes has revealed a vast number of BGCs containing smaller NRPS-like genes of unknown biosynthetic function. Using comparative metabolomics, we show that a BGC in the human pathogen Aspergillus fumigatus named fsq, which contains an NRPS-like gene lacking a condensation domain, produces several new isoquinoline alkaloids known as the fumisoquins. These compounds derive from carbon-carbon bond formation between two amino acid-derived moieties followed by a sequence that is directly analogous to isoquinoline alkaloid biosynthesis in plants. Fumisoquin biosynthesis requires the N-methyltransferase FsqC and the FAD-dependent oxidase FsqB, which represent functional analogs of coclaurine N-methyltransferase and berberine bridge enzyme in plants. Our results show that BGCs containing incomplete NRPS modules may reveal new biosynthetic paradigms and suggest that plant-like isoquinoline biosynthesis occurs in diverse fungi.

Authors: J. A. Baccile, J. E. Spraker, H. H. Le, E. Brandenburger, C. Gomez, J. W. Bok, J. Macheleidt, A. A. Brakhage, D. Hoffmeister, N. P. Keller, F. C. Schroeder

Date Published: 12th Apr 2016

Publication Type: Not specified

Plant-mediated RNAi silences midgut-expressed genes in congeneric lepidopteran insects in nature.

Abstract (Expand)

BACKGROUND: Plant-mediated RNAi (PMRi) silencing of insect genes has enormous potential for crop protection, but whether it works robustly under field conditions, particularly with lepidopteran pests, … remains controversial. Wild tobacco Nicotiana attenuata and cultivated tobacco (N. tabacum) (Solanaceae) is attacked by two closely related specialist herbivores Manduca sexta and M. quinquemaculata (Lepidoptera, Sphingidae). When M. sexta larvae attack transgenic N. attenuata plants expressing double-stranded RNA(dsRNA) targeting M. sexta's midgut-expressed genes, the nicotine-ingestion induced cytochrome P450 monooxygenase (invert repeat (ir)CYP6B46-plants) and the lyciumoside-IV-ingestion induced beta-glucosidase1 (irBG1-plants), these larval genes which are important for the larvae's response to ingested host toxins, are strongly silenced. RESULTS: Here we show that the PMRi procedure also silences the homologous genes in native M. quinquemaculata larvae feeding on irCYP6B46 and irBG1-transgenic N. attenuata plants in nature. The PMRi lines shared 98 and 96% sequence similarity with M. quinquemaculata homologous coding sequences, and CYP6B46 and BG1 transcripts were reduced by ca. 90 and 80%, without reducing the transcripts of the larvae's most similar, potential off-target genes. CONCLUSIONS: We conclude that the PMRi procedure can robustly and specifically silence genes in native congeneric insects that share sufficient sequence similarity and with the careful selection of targets, might protect crops from attack by congeneric-groups of insect pests.

Authors: S. Poreddy, J. Li, I. T. Baldwin

Date Published: 15th Nov 2017

Publication Type: Not specified

Polyhalogenation of Isoflavonoids by the Termite-Associated Actinomadura sp. RB99.

Abstract (Expand)

Based on high-resolution tandem mass spectrometry (HR-MS(2)) and global natural products social molecular networking (GNPS), we found that plant-derived daidzein and genistein derivatives are polyhalogenated … by termite-associated Actinomadura species RB99. MS-guided purification from extracts of bacteria grown under optimized conditions led to the isolation of eight polychlorinated isoflavones, including six unreported derivatives, and seven novel polybrominated derivatives, two of which showed antimicrobial activity.

Authors: S. Rak Lee, F. Schalk, J. W. Schwitalla, R. Benndorf, J. Vollmers, A. K. Kaster, Z. W. de Beer, M. Park, M. J. Ahn, W. H. Jung, C. Beemelmanns, K. H. Kim

Date Published: 23rd Oct 2020

Publication Type: Journal

Production Options for Psilocybin: Making of the Magic.

Abstract (Expand)

The fungal genus Psilocybe and other genera comprise numerous mushroom species that biosynthesize psilocybin (4-phosphoryloxy-N,N-dimethyltryptamine). It represents the prodrug to its dephosphorylated … psychotropic analogue, psilocin. The colloquial term "magic mushrooms" for these fungi alludes to their hallucinogenic effects and to their use as recreational drugs. However, clinical trials have recognized psilocybin as a valuable candidate to be developed into a medication against depression and anxiety. We here highlight its recently elucidated biosynthesis, the concurrently developed concept of enzymatic in vitro and heterologous in vivo production, along with previous synthetic routes. The prospect of psilocybin as a promising therapeutic may entail an increased demand, which can be met by biotechnological production. Therefore, we also briefly touch on psilocybin's therapeutic relevance and pharmacology.

Authors: J. Fricke, C. Lenz, J. Wick, F. Blei, D. Hoffmeister

Date Published: 18th Jan 2019

Publication Type: Journal

Pseudoxylallemycins A-F, Cyclic Tetrapeptides with Rare Allenyl Modifications Isolated from Pseudoxylaria sp. X802: A Competitor of Fungus-Growing Termite Cultivars.

Abstract (Expand)

Based on fungus-fungus pairing assays and HRMS-based dereplication strategy, six new cyclic tetrapeptides, pseudoxylallemycins A-F (1-6), were isolated from the termite-associated fungus Pseudoxylaria … sp. X802. Structures were characterized using NMR spectroscopy, HRMS, and Marfey's reaction. Pseudoxylallemycins B-D (2-4) possess a rare and chemically accessible allene moiety amenable for synthetic modifications, and derivatives A-D showed antimicrobial activity against Gram-negative human-pathogenic Pseudomonas aeruginosa and antiproliferative activity against human umbilical vein endothelial cells and K-562 cell lines.

Authors: H. Guo, N. B. Kreuzenbeck, S. Otani, M. Garcia-Altares, H. M. Dahse, C. Weigel, D. K. Aanen, C. Hertweck, M. Poulsen, C. Beemelmanns

Date Published: 25th Jun 2016

Publication Type: Not specified

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