Publications by authors named "Marco Kai"

40 Publications

Response of the wood-decay fungus Schizophyllum commune to co-occurring microorganisms.

PLoS One 2020 23;15(4):e0232145. Epub 2020 Apr 23.

Institute of Microbiology, Friedrich Schiller University, Jena, Germany.

Microorganisms are constantly interacting in a given environment by a constant exchange of signaling molecules. In timber, wood-decay fungi will come into contact with other fungi and bacteria. In naturally bleached wood, dark, pigmented lines arising from confrontation of two fungi often hint at such interactions. The metabolites (and pigment) exchange was investigated using the lignicolous basidiomycete Schizophyllum commune, and co-occurring fungi and bacteria inoculated directly on sterilized wood, or on media. In interactions with competitive wood degrading fungi, yeasts or bacteria, different competition strategies and communication types were observed, and stress reactions, as well as competitor-induced enzymes or pigments were analyzed. Melanin, indole, flavonoids and carotenoids were shown to be induced in S. commune interactions. The induced genes included multi-copper oxidases lcc1, lcc2, mco1, mco2, mco3 and mco4, possibly involved in both pigment production and lignin degradation typical for wood bleaching by wood-decay fungi.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0232145PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7179906PMC
July 2020

Diversity and Distribution of Volatile Secondary Metabolites Throughout Isolates.

Authors:
Marco Kai

Front Microbiol 2020 8;11:559. Epub 2020 Apr 8.

Institute for Biological Sciences, University of Rostock, Rostock, Germany.

releases a broad range of volatile secondary metabolites, which are considered as long- and short distance infochemical signals mediating inter- and intra-specific processes. In addition, they often show antimicrobial or antifungal activities. This review attempts to summarize yet known volatile secondary metabolites produced and emitted by isolates focusing on the structural diversity and distribution patterns. Using volatile-collection systems, 26 strains of isolated from different habitats were found to produce in total 231 volatile secondary metabolites. These volatile secondary metabolites comprised mainly hydrocarbons, ketones, alcohols, aldehydes, ester, acids, aromatics, sulfur- and nitrogen-containing compounds. Reviewed data revealed to a great extent isolate-specific emission patterns. The production and release of several volatile bioactive compounds was retained in isolates of the species , while volatiles without a described function seemed to be isolate-specifically produced. Detailed analysis, however, also indicated that the original data were strongly influenced by insufficient descriptions of the bacterial isolates, heterogeneous and poorly documented culture conditions as well as sampling techniques and inadequate compound identification. In order to get deeper insight into the nature, diversity, and ecological function of volatile secondary metabolites produced by , it will be necessary to follow well-documented workflows and fulfill state-of-the-art standards to unambiguously identify the volatile metabolites. Future research should consider the dynamic of a bacterial culture leading to differences in cell morphology and cell development. Single cell investigations could help to attribute certain volatile metabolites to defined cell forms and developmental stages.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fmicb.2020.00559DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7156558PMC
April 2020

Untargeted Metabolomics Approach Reveals Differences in Host Plant Chemistry Before and After Infestation With Different Pea Aphid Host Races.

Front Plant Sci 2019 28;10:188. Epub 2019 Feb 28.

Department of Biochemistry, Max-Planck Institute for Chemical Ecology, Jena, Germany.

The pea aphid (), a phloem-sucking insect, has undergone a rapid radiation together with the domestication and anthropogenic range expansion of several of its legume host plants. This insect species is a complex of at least 15 genetically different host races that can all develop on the universal host plant . However, each host race is specialized on a particular plant species, such as , , or , which makes it an attractive model insect to study ecological speciation. Previous work revealed that pea aphid host plants produce a specific phytohormone profile depending on the host plant - host race combination. Native aphid races induce lower defense hormone levels in their host plant than non-native pea aphid races. Whether these changes in hormone levels also lead to changes in other metabolites is still unknown. We used a mass spectrometry-based untargeted metabolomic approach to identify plant chemical compounds that vary among different host plant-host race combinations and might therefore, be involved in pea aphid host race specialization. We found significant differences among the metabolic fingerprints of the four legume species studied prior to aphid infestation, which correlated with aphid performance. After infestation, the metabolic profiles of and plants infested with their respective native aphid host race were consistently different from profiles after infestation with non-native host races and from uninfested control plants. The metabolic profiles of plants infested with their native aphid host race were also different from plants infested with non-native host races, but not different from uninfested control plants. The compounds responsible for these differences were putatively identified as flavonoids, saponins, non-proteinogenic amino acids and peptides among others. As members of these compound classes are known for their activity against insects and aphids in particular, they may be responsible for the differential performance of host races on native vs. non-native host plants. We conclude that the untargeted metabolomic approach is suitable to identify candidate compounds involved in the specificity of pea aphid - host plant interactions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fpls.2019.00188DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6403166PMC
February 2019

Publisher Correction: Interspecific formation of the antimicrobial volatile schleiferon.

Sci Rep 2019 Feb 26;9(1):3326. Epub 2019 Feb 26.

Institute of Biological Science, University of Rostock, Albert-Einstein-Straße 3, 18059, Rostock, Germany.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-018-37081-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6389958PMC
February 2019

Interspecific formation of the antimicrobial volatile schleiferon.

Sci Rep 2018 11 15;8(1):16852. Epub 2018 Nov 15.

Institute of Biological Science, University of Rostock, Albert-Einstein-Straße 3, 18059, Rostock, Germany.

Microorganisms release a plethora of volatile secondary metabolites. Up to now, it has been widely accepted that these volatile organic compounds are produced and emitted as a final product by a single organism e.g. a bacterial cell. We questioned this commonly assumed perspective and hypothesized that in diversely colonized microbial communities, bacterial cells can passively interact by emitting precursors which non-enzymatically react to form the active final compound. This hypothesis was inspired by the discovery of the bacterial metabolite schleiferon A. This bactericidal volatile compound is formed by a non-enzymatic reaction between acetoin and 2-phenylethylamine. Both precursors are released by Staphylococcus schleiferi cells. In order to provide evidence for our hypothesis that these precursors could also be released by bacterial cells of different species, we simultaneously but separately cultivated Serratia plymuthica 4Rx13 and Staphylococcus delphini 20771 which held responsible for only one precursor necessary for schleiferon A formation, respectively. By mixing their headspace, we demonstrated that these two species were able to deliver the active principle schleiferon A. Such a joint formation of a volatile secondary metabolite by different bacterial species has not been described yet. This highlights a new aspect of interpreting multispecies interactions in microbial communities as not only direct interactions between species might determine and influence the dynamics of the community. Events outside the cell could lead to the appearance of new compounds which could possess new community shaping properties.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-018-35341-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6237861PMC
November 2018

Interspecies interaction of Serratia plymuthica 4Rx13 and Bacillus subtilis B2g alters the emission of sodorifen.

FEMS Microbiol Lett 2018 11;365(22)

Institute of Biological Sciences, University of Rostock, Albert-Einstein-Strasse 3, 18059 Rostock, Germany.

Sodorifen is the major volatile of Serratia plymuthica 4Rx13. It is assumed to be a long-distance communication signal. However, so far the emission patterns of sodorifen had been studied using mono-cultures of S. plymuthica 4Rx13 neglecting that in natura bacteria live in communities. Here, we show that the structured co-cultivation of S. plymuthica 4Rx13 and Bacillus subtilis B2g in a low-diversity model community grown under nutrient-rich conditions led to quantitative changes in sodorifen emission compared to self-paired mono-cultivations. Co-culturing revealed a decreased emission of sodorifen (50%) during exponential growth phase, whereas in the late stationary stage of growth, the amount of headspace sodorifen was increased compared to self-paired mono-cultivation (217% at 500 h of cultivation). Six other compounds that are most probably related to sodorifen or are isomers showed similar emission patterns. These data indicated that S. plymuthica 4Rx13 enhances its communication signal sodorifen as a consequence of interaction with B. subtilis B2g.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/femsle/fny253DOI Listing
November 2018

Sodorifen Biosynthesis in the Rhizobacterium Serratia plymuthica Involves Methylation and Cyclization of MEP-Derived Farnesyl Pyrophosphate by a SAM-Dependent C-Methyltransferase.

J Am Chem Soc 2018 09 4;140(37):11855-11862. Epub 2018 Sep 4.

Institute for Biological Sciences , University of Rostock , Albert-Einstein-Straße 3 , D-18059 Rostock , Germany.

The rhizobacterium Serratia plymuthica 4Rx13 releases a unique polymethylated hydrocarbon (CH) with a bicyclo[3.2.1]octadiene skeleton called sodorifen. Sodorifen production depends on a gene cluster carrying a C-methyltransferase and a terpene cyclase along with two enzymes of the 2- C-methyl-d-erythritol 4-phosphate (MEP) pathway of isoprenoid biosynthesis. Comparative analysis of wild-type and mutant volatile organic compound profiles revealed a C-methyltransferase-dependent C alcohol called pre-sodorifen, the production of which is upregulated in the terpene cyclase mutant. The monocyclic structure of this putative intermediate in sodorifen biosynthesis was identified by NMR spectroscopy. In vitro assays with the heterologously expressed S. plymuthica C-methyltransferase and terpene cyclase demonstrated that these enzymes act sequentially to convert farnesyl pyrophosphate (FPP) into sodorifen via a pre-sodorifen pyrophosphate intermediate, indicating that the S-adenosyl methionine (SAM)-dependent C-methyltransferase from S. plymuthica exhibits unprecedented cyclase activity. In vivo incorporation experiments with C-labeled succinate, l-alanine, and l-methionine confirmed a MEP pathway to FPP via the canonical glyceraldehyde-3-phosphate and pyruvate, as well as its SAM-dependent methylation in pre-sodorifen and sodorifen biosynthesis. C{H} NMR spectroscopy facilitated the localization of C labels and provided detailed insights into the biosynthetic pathway from FPP via pre-sodorifen pyrophosphate to sodorifen.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jacs.8b08510DOI Listing
September 2018

Evolutionary stability of antibiotic protection in a defensive symbiosis.

Proc Natl Acad Sci U S A 2018 Feb 14;115(9):E2020-E2029. Epub 2018 Feb 14.

Insect Symbiosis Research Group, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany;

The increasing resistance of human pathogens severely limits the efficacy of antibiotics in medicine, yet many animals, including solitary beewolf wasps, successfully engage in defensive alliances with antibiotic-producing bacteria for millions of years. Here, we report on the in situ production of 49 derivatives belonging to three antibiotic compound classes (45 piericidin derivatives, 3 streptochlorin derivatives, and nigericin) by the symbionts of 25 beewolf host species and subspecies, spanning 68 million years of evolution. Despite a high degree of qualitative stability in the antibiotic mixture, we found consistent quantitative differences between species and across geographic localities, presumably reflecting adaptations to combat local pathogen communities. Antimicrobial bioassays with the three main components and in silico predictions based on the structure and specificity in polyketide synthase domains of the piericidin biosynthesis gene cluster yield insights into the mechanistic basis and ecoevolutionary implications of producing a complex mixture of antimicrobial compounds in a natural setting.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.1719797115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5834716PMC
February 2018

Effects of discrete bioactive microbial volatiles on plants and fungi.

Plant Cell Environ 2017 Oct 24;40(10):2042-2067. Epub 2017 Aug 24.

Institute for Biological Sciences, University of Rostock, Albert-Einstein-Str. 3, 18059, Rostock, Germany.

Plants live in association with microorganisms, which are well known as a rich source of specialized metabolites, including volatile compounds. The increasing numbers of described plant microbiomes allowed manifold phylogenetic tree deductions, but less emphasis is presently put on the metabolic capacities of plant-associated microorganisms. With the focus on small volatile metabolites we summarize (i) the knowledge of prominent bacteria of plant microbiomes; (ii) present the state-of-the-art of individual (discrete) microbial organic and inorganic volatiles affecting plants and fungi; and (iii) emphasize the high potential of microbial volatiles in mediating microbe-plant interactions. So far, 94 discrete organic and five inorganic compounds were investigated, most of them trigger alterations of the growth, physiology and defence responses in plants and fungi but little is known about the specific molecular and cellular targets. Large overlaps in emission profiles of the emitters and receivers render specific volatile organic compound-mediated interactions highly unlikely for most bioactive mVOCs identified so far.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/pce.13011DOI Listing
October 2017

Exploring bacterial interspecific interactions for discovery of novel antimicrobial compounds.

Microb Biotechnol 2017 07 29;10(4):910-925. Epub 2017 May 29.

Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), PO BOX 50, 6700 AB, Wageningen, The Netherlands.

Recent studies indicated that the production of secondary metabolites by soil bacteria can be triggered by interspecific interactions. However, little is known to date about interspecific interactions between Gram-positive and Gram-negative bacteria. In this study, we aimed to understand how the interspecific interaction between the Gram-positive Paenibacillus sp. AD87 and the Gram-negative Burkholderia sp. AD24 affects the fitness, gene expression and the production of soluble and volatile secondary metabolites of both bacteria. To obtain better insight into this interaction, transcriptome and metabolome analyses were performed. Our results revealed that the interaction between the two bacteria affected their fitness, gene expression and the production of secondary metabolites. During interaction, the growth of Paenibacillus was not affected, whereas the growth of Burkholderia was inhibited at 48 and 72 h. Transcriptome analysis revealed that the interaction between Burkholderia and Paenibacillus caused significant transcriptional changes in both bacteria as compared to the monocultures. The metabolomic analysis revealed that the interaction increased the production of specific volatile and soluble antimicrobial compounds such as 2,5-bis(1-methylethyl)-pyrazine and an unknown Pederin-like compound. The pyrazine volatile compound produced by Paenibacillus was subjected to bioassays and showed strong inhibitory activity against Burkholderia and a range of plant and human pathogens. Moreover, strong additive antimicrobial effects were observed when soluble extracts from the interacting bacteria were combined with the pure 2,5-bis(1-methylethyl)-pyrazine. The results obtained in this study highlight the importance to explore bacterial interspecific interactions to discover novel secondary metabolites and to perform simultaneously metabolomics of both, soluble and volatile compounds.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/1751-7915.12735DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5481530PMC
July 2017

Local phytochemical response of Musa acuminata × balbisiana Colla cv. 'Bluggoe' (ABB) to colonization by Sternorrhyncha.

Phytochemistry 2017 Jan 11;133:26-32. Epub 2016 Nov 11.

Research Group Biosynthesis/NMR, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07745 Jena, Germany. Electronic address:

The interaction of two Sternorrhyncha species, the banana aphid (Pentalonia nigronervosa Coquerel (Hemiptera: Aphididae, Aphidinae)), vector of the banana bunchy top virus (BBTV), and the latania scale (Hemiberlesia lataniae Signoret (Hemiptera: Diaspididae, Diaspidinae)) with Musa acuminata × balbisiana Colla (ABB Group) 'Bluggoe' (Musaceae) was investigated by a combination of conventional and spatially resolved analytical techniques, H NMR, UHPLC-MS, and matrix-free UV-laser desorption/ionization MS imaging. After infestation, the feeding sites of P. nigronervosa on the pseudostem and the exocarp of banana fruit developed a red tinge, in which tissue-specific accumulations of phenylphenalenones were discovered. Phenylphenalenones were also detected in the black mats of sooty molds growing on the banana aphid exudates and in the dorsal scales of H. lataniae. This suggests that although these secondary metabolites play a role in the reaction of banana plants towards attack by sucking insects, an aphid and an armored scale have established mechanisms to exude these metabolites before they deploy their deleterious effect.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.phytochem.2016.10.007DOI Listing
January 2017

Novel volatiles of skin-borne bacteria inhibit the growth of Gram-positive bacteria and affect quorum-sensing controlled phenotypes of Gram-negative bacteria.

Syst Appl Microbiol 2016 Dec 27;39(8):503-515. Epub 2016 Sep 27.

University of Rostock, Institute of Biological Sciences, Albert-Einstein-Strasse 3, 18059 Rostock, Germany. Electronic address:

The skin microbiota is import for body protection. Here we present the first comprehensive analysis of the volatile organic compound (VOC) profiles of typical skin-resident corynebacterial and staphylococcal species. The VOC profile of Staphylococcus schleiferi DSMZ 4807 was of particular interest as it is dominated by two compounds, 3-(phenylamino)butan-2-one and 3-(phenylimino)butan-2-one (schleiferon A and B, respectively). Neither of these has previously been reported from natural sources. Schleiferon A and B inhibited the growth of various Gram-positive species and affected two quorum-sensing-dependent phenotypes - prodigiosin accumulation and bioluminescence - of Gram-negative bacteria. Both compounds were found to inhibit the expression of prodigiosin biosynthetic genes and stimulate the expression of prodigiosin regulatory genes pigP and pigS. This study demonstrates that the volatile schleiferons A and B emitted by the skin bacterium S. schleiferi modulate differentially and specifically its interactions with members of diverse bacterial communities. A network of VOC-mediated interspecies interactions and communications must be considered in the establishment of the (skin) microbiome and both compounds are interesting candidates for further investigations to better understand how VOCs emitted by skin bacteria influence and modulate the local microbiota and determine whether they are relevant to antibiotic and anti-virulence therapies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.syapm.2016.08.008DOI Listing
December 2016

Bacterial-Plant-Interactions: Approaches to Unravel the Biological Function of Bacterial Volatiles in the Rhizosphere.

Front Microbiol 2016 9;7:108. Epub 2016 Feb 9.

Department of Biochemistry, Institute of Biological Science, University of Rostock Rostock, Germany.

Rhizobacteria produce an enormous amount of volatile compounds, however, the function of these metabolites is scarcely understood. Investigations evaluating influences on plants performed in various laboratories using individually developed experimental setups revealed different and often contradictory results, e.g., ranging from a significant plant growth promotion to a dramatic suppression of plant development. In addition to these discrepancies, these test systems neglected properties and complexity of the rhizosphere. Therefore, to pursue further investigations of the role of bacterial volatiles in this underground habitat, the applied methods have to simulate its natural characteristics as much as possible. In this review, we will describe and discuss pros and cons of currently used bioassays, give insights into rhizosphere characteristics, and suggest improvements for test systems that would consider in natura conditions and would allow gaining further knowledge of the potential function and significance of rhizobacterial volatiles in plant life.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fmicb.2016.00108DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4746483PMC
February 2016

Unprecedented Utilization of Pelargonidin and Indole for the Biosynthesis of Plant Indole Alkaloids.

Chembiochem 2016 Feb 28;17(4):318-27. Epub 2016 Jan 28.

Max Planck Institut für chemische Ökologie, Hans Knöll Strasse 8, 07745, Jena, Germany.

Nudicaulins are a group of indole alkaloid glycosides responsible for the color of yellow petals of Papaver nudicaule (Iceland poppy). The unique aglycone scaffold of these alkaloids attracted our interest as one of the most unusual flavonoid-indole hybrid structures that occur in nature. Stable isotope labeling experiments with sliced petals identified free indole, but not tryptamine or l-tryptophan, as one of the two key biosynthetic precursors of the nudicaulin aglycone. Pelargonidin was identified as the second key precursor, contributing the polyphenolic unit to the nudicaulin molecule. This finding was inferred from the temporary accumulation of pelargonidin glycosides in the petals during flower bud development and a drop at the point in time when nudicaulin levels start to increase. The precursor-directed incorporation of cyanidin into a new 3'-hydroxynudicaulin strongly supports the hypothesis that anthocyanins are involved in the biosynthesis of nudicaulins.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cbic.201500572DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4770437PMC
February 2016

Influence of zygomycete-derived D'orenone on IAA signalling in Tricholoma-spruce ectomycorrhiza.

Environ Microbiol 2016 09 18;18(8):2470-80. Epub 2016 Jan 18.

Institute of Microbiology, Microbial Communication, Friedrich Schiller University Jena, Neugasse 25, 07745, Jena, Germany.

Despite the rising interest in microbial communication, only few studies relate to mycorrhization and the pool of potential morphogenic substances produced by the surrounding soil community. Here, we investigated the effect exerted by the C18 - ketone β-apo-13-carotenone, D'orenone, on the ectomycorrhizal basidiomycete Tricholoma vaccinum and its symbiosis with the economically important host tree, spruce (Picea abies). D'orenone is an early intermediate in the biosynthesis of morphogens in sexual development of mucoromycetes, the trisporoids. In the ectomycorrhizal fungus T. vaccinum, D'orenone increased the production and/or release of the phytohormone indole-3-acetic acid (IAA) which had been proposed to be involved in the mutual symbiosis. The induced expression of the fungal aldehyde dehydrogenase, Ald5 is associated with IAA synthesis and excretion. In the host tree, D'orenone modulated root architecture by increasing lateral root length and hypertrophy of root cortex cells, likely via changed IAA concentrations and flux. Thus, we report for the first time on carotenoid metabolites from soil fungi affecting both ectomycorrhizal partners. The data imply a complex network of functions for secondary metabolites which act in an inter-kingdom signalling in soil.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/1462-2920.13160DOI Listing
September 2016

4-Methoxycinnamic acid--An unusual phenylpropanoid involved in phenylphenalenone biosynthesis in Anigozanthos preissii.

Phytochemistry 2015 Sep 25;117:476-481. Epub 2015 Jul 25.

Max-Planck Institut für Chemische Ökologie, Beutenberg Campus, Hans-Knöll-Strasse 8, 07745 Jena, Germany. Electronic address:

In vitro root cultures of Anigozanthos preissii and Wachendorfia thyrsiflora (Haemodoraceae) are suitable biological systems for studying the biosynthesis of phenylphenalenones. Here we report how we used these root cultures to investigate precursor-product relationships between phenylpropanoids and phenylphenalenones whose phenyl rings share identical substitution patterns. Four phenylpropanoic acids, including ferulic acid and the unusual 4-methoxycinnamic acid, were used in (13)C-labeled form as substrates to study their incorporation into phenylphenalenones. In addition to the previously reported 2-hydroxy-9-(4'-hydroxy-3'-methoxyphenyl)-1H-phenalen-1-one (trivial name musanolone F), 2-hydroxy-9-(4'-methoxyphenyl)-1H-phenalen-1-one (proposed trivial name 4'-methoxyanigorufone) was found as a biosynthetic product in A. preissii. The carbon skeleton of 4'-methoxycinnamic acid was biosynthetically incorporated as an intact unit including its 4'-O-methyl substituent at the lateral phenyl ring. 4'-Methoxyanigorufone is reported here for the first time as a natural product.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.phytochem.2015.07.017DOI Listing
September 2015

Monitoring metabolites from Schizophyllum commune interacting with Hypholoma fasciculare combining LESA-HR mass spectrometry and Raman microscopy.

Anal Bioanal Chem 2015 Mar 27;407(8):2273-82. Epub 2014 Dec 27.

Department of Microbial Communication, Institute of Microbiology, Friedrich Schiller University, Neugasse 25, 07743, Jena, Germany.

Microbial competition for territory and resources is inevitable in habitats with overlap between niches of different species or strains. In fungi, competition is brought about by antagonistic mycelial interactions which alter mycelial morphology, metabolic processes, secondary metabolite release, and extracellular enzyme patterns. Until now, we were not able study in vivo chemical interactions of different colonies growing on the same plate. In this report, we developed a fast and least invasive approach to identify, quantify, and visualize co culture-induced metabolites and their location of release within Schizophyllum commune. The pigments indigo, indirubin, and isatin were used as examples to show secondary metabolite production in the interaction zone with Hypholoma fasciculare. Using a combinatory approach of Raman spectroscopy imaging, liquid extraction surface analysis (LESA), and high-resolution mass spectrometry, we identified, quantified, and visualized the presence of indigo and indirubin in the interaction zone. This approach allows the investigation of metabolite patterns between wood degrading species in competition to gain insight in community interactions, but could also be applied to other microorganisms. This method advances analysis of living, still developing colonies and are in part not destructive as Raman spectroscopy imaging is implemented.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00216-014-8383-6DOI Listing
March 2015

Dopamine drives Drosophila sechellia adaptation to its toxic host.

Elife 2014 Dec 9;3. Epub 2014 Dec 9.

Max Planck Institute for Chemical Ecology, Jena, Germany.

Many insect species are host-obligate specialists. The evolutionary mechanism driving the adaptation of a species to a toxic host is, however, intriguing. We analyzed the tight association of Drosophila sechellia to its sole host, the fruit of Morinda citrifolia, which is toxic to other members of the melanogaster species group. Molecular polymorphisms in the dopamine regulatory protein Catsup cause infertility in D. sechellia due to maternal arrest of oogenesis. In its natural host, the fruit compensates for the impaired maternal dopamine metabolism with the precursor l-DOPA, resuming oogenesis and stimulating egg production. l-DOPA present in morinda additionally increases the size of D. sechellia eggs, what in turn enhances early fitness. We argue that the need of l-DOPA for successful reproduction has driven D. sechellia to become an M. citrifolia obligate specialist. This study illustrates how an insect's dopaminergic system can sustain ecological adaptations by modulating ontogenesis and development.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7554/eLife.03785DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4270095PMC
December 2014

Antibiotic oxylipins from Alternanthera brasiliana and its endophytic bacteria.

Phytochemistry 2015 Feb 26;110:72-82. Epub 2014 Nov 26.

LaBioMMi, Federal University of São Carlos, Rodovia Washington Luiz, km 235, CP 676, São Carlos - SP 13.565-905, Brazil.

Bioassay-guided fractionation of Alternanthera brasiliana stem extracts resulted in the isolation of an antibiotically active fraction. Five human pathogenic bacteria were used to guide the fractionation process for the isolation of antimicrobial compounds. Finally, 17 linoleate oxylipins were identified by LC-MS/MS and NMR spectroscopy. Five of the isolated compounds present in A. brasiliana tissues were also detected to be synthesized by endophytic bacteria of the genus Bacillus that were isolated from A. brasiliana. It is speculated that the antibiotic oxylipins from A. brasiliana might derive from bacteria and be involved in an ecological relationship between this plant and its endophytes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.phytochem.2014.11.005DOI Listing
February 2015

Functional heterologous production of reductive dehalogenases from Desulfitobacterium hafniense strains.

Appl Environ Microbiol 2014 Jul 9;80(14):4313-22. Epub 2014 May 9.

Department of Applied and Ecological Microbiology, Institute of Microbiology, Friedrich Schiller University, Jena, Germany

The anaerobic dehalogenation of organohalides is catalyzed by the reductive dehalogenase (RdhA) enzymes produced in phylogenetically diverse bacteria. These enzymes contain a cobamide cofactor at the active site and two iron-sulfur clusters. In this study, the tetrachloroethene (PCE) reductive dehalogenase (PceA) of the Gram-positive Desulfitobacterium hafniense strain Y51 was produced in a catalytically active form in the nondechlorinating, cobamide-producing bacterium Shimwellia blattae (ATCC 33430), a Gram-negative gammaproteobacterium. The formation of recombinant catalytically active PceA enzyme was significantly enhanced when its dedicated PceT chaperone was coproduced and when 5,6-dimethylbenzimidazole and hydroxocobalamin were added to the S. blattae cultures. The experiments were extended to D. hafniense DCB-2, a reductively dehalogenating bacterium harboring multiple rdhA genes. To elucidate the substrate spectrum of the rdhA3 gene product of this organism, the recombinant enzyme was tested for the conversion of different dichlorophenols (DCP) in crude extracts of an RdhA3-producing S. blattae strain. 3,5-DCP, 2,3-DCP, and 2,4-DCP, but not 2,6-DCP and 3,4-DCP, were reductively dechlorinated by the recombinant RdhA3. In addition, this enzyme dechlorinated PCE to trichloroethene at low rates.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/AEM.00881-14DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4068680PMC
July 2014

VOC emission of various Serratia species and isolates and genome analysis of Serratia plymuthica 4Rx13.

FEMS Microbiol Lett 2014 Mar 7;352(1):45-53. Epub 2014 Jan 7.

Institute of Biological Sciences, University of Rostock, Rostock, Germany.

Bacteria emit a wealth of volatile organic compounds. Gas chromatography coupled to mass spectrometry analysis of five Serratia strains revealed ketones, dimethyl di- and trisulfide and 2-phenylethanol commonly released in this genus. The polymethylated bicyclic hydrocarbon sodorifen was uniquely released by the rhizobacterium Serratia plymuthica 4Rx13. Of 10 Serratia strains, only S. plymuthica isolates originating from plants grown on fields near Rostock (Germany) released this new and unusual compound. Since the biosynthetic pathway of sodorifen was unknown, the genome sequence of S. plymuthica 4Rx13 was determined and annotated. Genome comparison of S. plymuthica 4Rx13 with sodorifen non-producing Serratia species highlighted 246 unique candidate open reading frames.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/1574-6968.12359DOI Listing
March 2014

Phenalenone-type phytoalexins mediate resistance of banana plants (Musa spp.) to the burrowing nematode Radopholus similis.

Proc Natl Acad Sci U S A 2014 Jan 9;111(1):105-10. Epub 2013 Dec 9.

Nuclear Magnetic Resonance Research Group, Mass Spectrometry Research Group, Department of Entomology, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany.

The global yield of bananas-one of the most important food crops-is severely hampered by parasites, such as nematodes, which cause yield losses up to 75%. Plant-nematode interactions of two banana cultivars differing in susceptibility to Radopholus similis were investigated by combining the conventional and spatially resolved analytical techniques (1)H NMR spectroscopy, matrix-free UV-laser desorption/ionization mass spectrometric imaging, and Raman microspectroscopy. This innovative combination of analytical techniques was applied to isolate, identify, and locate the banana-specific type of phytoalexins, phenylphenalenones, in the R. similis-caused lesions of the plants. The striking antinematode activity of the phenylphenalenone anigorufone, its ingestion by the nematode, and its subsequent localization in lipid droplets within the nematode is reported. The importance of varying local concentrations of these specialized metabolites in infected plant tissues, their involvement in the plant's defense system, and derived strategies for improving banana resistance are highlighted.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.1314168110DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3890884PMC
January 2014

Synthesis of isoxazolin-5-one glucosides by a cascade reaction.

J Org Chem 2013 Dec 3;78(24):12779-83. Epub 2013 Dec 3.

Max Planck Institute for Chemical Ecology , Beutenberg Campus, Hans-Knoell-Straße 8, D-07745 Jena, Germany.

A novel synthetic route was developed for the construction of isoxazolin-5-one glucosides using a cascade reaction. An X-ray crystal structure analysis of a isoxazolin-5-one glucoside confirmed the structure and stereochemistry of the heterocycle. The properties of the α- and β-anomers of the isoxazolin-5-one glucosides were compared. The first synthesis of 2-[6'-(3″-nitropropanoyl)-β-D-glucopyranosyl]-3-isoxazolin-5-one was realized by direct enzymatic esterification without need of further protective groups.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jo4023155DOI Listing
December 2013

Bacterial ammonia causes significant plant growth inhibition.

PLoS One 2013 15;8(5):e63538. Epub 2013 May 15.

University of Rostock, Institute of Biological Sciences, Rostock, Germany.

Many and complex plant-bacteria inter-relationships are found in the rhizosphere, since plants release a variety of photosynthetic exudates from their roots and rhizobacteria produce multifaceted specialized compounds including rich mixtures of volatiles, e.g., the bouquet of Serratia odorifera 4Rx13 is composed of up to 100 volatile organic and inorganic compounds. Here we show that when growing on peptone-rich nutrient medium S. odorifera 4Rx13 and six other rhizobacteria emit high levels of ammonia, which during co-cultivation in compartmented Petri dishes caused alkalization of the neighboring plant medium and subsequently reduced the growth of A. thaliana. It is argued that in nature high-protein resource degradations (carcasses, whey, manure and compost) are also accompanied by bacterial ammonia emission which alters the pH of the rhizosphere and thereby influences organismal diversity and plant-microbe interactions. Consequently, bacterial ammonia emission may be more relevant for plant colonization and growth development than previously thought.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0063538PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3655192PMC
January 2014

4-Deoxyaurone formation in Bidens ferulifolia (Jacq.) DC.

PLoS One 2013 8;8(5):e61766. Epub 2013 May 8.

Institut für Verfahrenstechnik, Umwelttechnik und Technische Biowissenschaften, Technische Universität Wien, Wien, Austria.

The formation of 4-deoxyaurones, which serve as UV nectar guides in Bidens ferulifolia (Jacq.) DC., was established by combination of UV photography, mass spectrometry, and biochemical assays and the key step in aurone formation was studied. The yellow flowering ornamental plant accumulates deoxy type anthochlor pigments (6'-deoxychalcones and the corresponding 4-deoxyaurones) in the basal part of the flower surface whilst the apex contains only yellow carotenoids. For UV sensitive pollinating insects, this appears as a bicoloured floral pattern which can be visualized in situ by specific ammonia staining of the anthochlor pigments. The petal back side, in contrast, shows a faintly UV absorbing centre and UV absorbing rays along the otherwise UV reflecting petal apex. Matrix-free UV laser desorption/ionisation mass spectrometric imaging (LDI-MSI) indicated the presence of 9 anthochlors in the UV absorbing areas. The prevalent pigments were derivatives of okanin and maritimetin. Enzyme preparations from flowers, leaves, stems and roots of B. ferulifolia and from plants, which do not accumulate aurones e.g. Arabidopsis thaliana, were able to convert chalcones to aurones. Thus, aurone formation could be catalyzed by a widespread enzyme and seems to depend mainly on a specific biochemical background, which favours the formation of aurones at the expense of flavonoids. In contrast to 4-hydroxyaurone formation, hydroxylation and oxidative cyclization to the 4-deoxyaurones does not occur in one single step but is catalyzed by two separate enzymes, chalcone 3-hydroxylase and aurone synthase (catechol oxidase reaction). Aurone formation shows an optimum at pH 7.5 or above, which is another striking contrast to 4-hydroxyaurone formation in Antirrhinum majus L. This is the first example of a plant catechol oxidase type enzyme being involved in the flavonoid pathway and in an anabolic reaction in general.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0061766PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3648546PMC
December 2013

Metabolic profiling of lignans and other secondary metabolites from rapeseed ( Brassica napus L.).

J Agric Food Chem 2012 Oct 15;60(42):10523-9. Epub 2012 Oct 15.

Max Planck Institute for Chemical Ecology, Beutenberg Campus, Hans-Knöll Strasse 8, D-07745 Jena, Germany.

A metabolic profiling study was carried out on rapeseed ( Brassica napus L.). Eleven glucosinolates were identified by high-performance liquid chromatography (HPLC) coupled with diode array detection (DAD) and mass spectrometry (MS). Additionally, 18 phenolic compounds were profiled from an ethanol extract of rapeseed. Besides two major phenols, sinapine and methyl sinapate, 16 minor phenolic compounds were isolated and identified. Seven of them are new lignans including three (±)-thomasidioic acid derivatives and four (E,E)-dienolignan derivatives. The structures of novel phenolic compounds were elucidated by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy and MS. The analytical data of secondary metabolites in rapeseed winter cultivar "Emerald" and information about purification on a microscale are useful for upcoming studies on tissue-specific localization of these compounds.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jf303907bDOI Listing
October 2012

Direct mass spectrometric screening of antibiotics from bacterial surfaces using liquid extraction surface analysis.

Rapid Commun Mass Spectrom 2012 Oct;26(20):2477-82

Research Group Mass Spectrometry, Max Planck Institute for Chemical Ecology, Jena, Germany.

Rationale: There is a need to find new antibiotic agents to fight resistant pathogenic bacteria. To search successfully for novel antibiotics from bacteria cultivated under diverse conditions, we need a fast and cost-effective screening method.

Methods: A combination of Liquid Extraction Surface Analysis (LESA), automated chip-based nanoelectrospray ionization, and high-resolution mass or tandem mass spectrometry using an Orbitrap XL was tested as the screening platform. Actinobacteria, known to produce well-recognized thiazolyl peptide antibiotics, were cultivated on a plate of solid medium and the antibiotics were extracted by organic solvent mixtures from the surface of colonies grown on the plate and analyzed using mass spectrometry (MS).

Results: LESA combined with high-resolution MS is a powerful tool with which to extract and detect thiazolyl peptide antibiotics from different Actinobacteria. Known antibiotics were correctly detected with high mass accuracy (<4 ppm) and structurally characterized using tandem mass spectra. Our method is the first step toward the development of a novel high-throughput extraction and identification tool for antibiotics in particular and natural products in general.

Conclusions: The method described in this paper is suitable for (1) screening the natural products produced by bacterial colonies on cultivation plates within the first 2 min following extraction and (2) detecting antibiotics at high mass accuracy; the cost is around 2 Euro per sample.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/rcm.6365DOI Listing
October 2012

Phytochemical profile of aerial parts and roots of Wachendorfia thyrsiflora L. studied by LC-DAD-SPE-NMR.

Phytochemistry 2012 Sep 18;81:144-52. Epub 2012 Jun 18.

Max Planck Institute for Chemical Ecology, Beutenberg Campus, Jena, Germany.

Hyphenated liquid chromatography - diode array detection - solid phase extraction - nuclear magnetic resonance spectroscopy (LC-DAD-SPE-NMR) was used to investigate the phytochemical composition of aerial parts and roots of Wachendorfia thyrsiflora (Haemodoraceae). Eleven phenylphenalenones and related compounds were identified in the aerial parts of the plant, ten compounds were found in the roots, and four additional compounds occurred in both plant parts. Twelve compounds are previously unreported natural products including five alkaloids (phenylbenzoisoquinolinones) are described here for the first time. In the work presented here, phenylphenalenones with an intact C(19) core structure were found only in the roots. Oxa analogs with a C(18)O scaffold occurred both in the roots and in the aerial plant parts, while most of the aza analogs with a C(18)N scaffold were detected in the aerial plant parts. This distribution pattern suggests that phenylphenalenones form in the roots, then the intact C(19) skeleton is converted into oxa analogs in the roots, translocated into the leaves and further reacted with amines or amino acids to form aza analogs (phenylbenzoisoquinolin-1,6-dione alkaloids).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.phytochem.2012.05.023DOI Listing
September 2012

Volatile organic compounds produced by the phytopathogenic bacterium Xanthomonas campestris pv. vesicatoria 85-10.

Beilstein J Org Chem 2012 17;8:579-96. Epub 2012 Apr 17.

University of Rostock, Institute of Biological Sciences, Albert-Einstein-Str. 3, 18059 Rostock, Germany.

Xanthomonas campestris is a phytopathogenic bacterium and causes many diseases of agricultural relevance. Volatiles were shown to be important in inter- and intraorganismic attraction and defense reactions. Recently it became apparent that also bacteria emit a plethora of volatiles, which influence other organisms such as invertebrates, plants and fungi. As a first step to study volatile-based bacterial-plant interactions, the emission profile of Xanthomonas c. pv. vesicatoria 85-10 was determined by using GC/MS and PTR-MS techniques. More than 50 compounds were emitted by this species, the majority comprising ketones and methylketones. The structure of the dominant compound, 10-methylundecan-2-one, was assigned on the basis of its analytical data, obtained by GC/MS and verified by comparison of these data with those of a synthetic reference sample. Application of commercially available decan-2-one, undecan-2-one, dodecan-2-one, and the newly synthesized 10-methylundecan-2-one in bi-partite Petri dish bioassays revealed growth promotions in low quantities (0.01 to 10 μmol), whereas decan-2-one at 100 μmol caused growth inhibitions of the fungus Rhizoctonia solani. Volatile emission profiles of the bacteria were different for growth on media (nutrient broth) with or without glucose.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3762/bjoc.8.65DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3343284PMC
August 2012

Identifying the unknowns by aligning fragmentation trees.

Anal Chem 2012 Apr 20;84(7):3417-26. Epub 2012 Mar 20.

Chair for Bioinformatics, Friedrich Schiller University, Jena, Germany.

Mass spectrometry allows sensitive, automated, and high-throughput analysis of small molecules. In principle, tandem mass spectrometry allows us to identify "unknown" small molecules not in any database, but the automated interpretation of such data is in its infancy. Fragmentation trees have recently been introduced for the automated analysis of the fragmentation patterns of small molecules. We present a method for the automated comparison of such fragmentation patterns, based on aligning the compounds' fragmentation trees. We cluster compounds based solely on their fragmentation patterns and show a good agreement with known compound classes. Fragmentation pattern similarities are strongly correlated with the chemical similarity of molecules. We present a tool for searching a database for compounds with fragmentation pattern similar to an unknown sample compound. We apply this tool to metabolites from Icelandic poppy. Our method allows fully automated computational identification of small molecules that cannot be found in any database.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/ac300304uDOI Listing
April 2012