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Soils are important for ecosystem functioning and service provisioning. Soil communities and their functions, in turn, are strongly promoted by plant diversity, and such positive effects strengthen with time. However, plant diversity effects on soil organic matter have mostly been investigated in the topsoil, and there are only very few long-term studies. Thus, it remains unclear if plant diversity effects strengthen with time and to which depth these effects extend. Here, we repeatedly sampled soil to 1 m depth in a long-term grassland biodiversity experiment. We investigated how plant diversity impacted soil organic carbon and nitrogen concentrations and stocks and their stable isotopes 13C and 15N, as well as how these effects changed after 5, 10, and 14 years. We found that higher plant diversity increased carbon and nitrogen storage in the topsoil since the establishment of the experiment. Stable isotopes revealed that these increases were associated with new plant-derived inputs, resulting in less processed and less decomposed soil organic matter. In subsoils, mainly the presence of specific plant functional groups drove organic matter dynamics. For example, the presence of deep-rooting tall herbs decreased carbon concentrations, most probably through stimulating soil organic matter decomposition. Moreover, plant diversity effects on soil organic matter became stronger in topsoil over time and reached subsoil layers, while the effects of specific plant functional groups in subsoil progressively diminished over time. Our results indicate that after changing the soil system the pathways of organic matter transfer to the subsoil need time to establish. In our grassland system, organic matter storage in subsoils was driven by the redistribution of already stored soil organic matter from the topsoil to deeper soil layers, for example, via bioturbation or dissolved organic matter. Therefore, managing plant diversity may, thus, have significant implications for subsoil carbon storage and other critical ecosystem services.

This study examined the influence of pectinase-producing non-Saccharomyces yeasts on the chemical and sensory attributes of red and white wines with added pectin. Merlot and Chardonnay wines were produced with or without a mixture of pectinase-producing non-Saccharomyces yeasts (Cryptococcus adeliensis, Issatchenkia orientalis, and Pichia kluyveri) added to the must prior to alcoholic fermentation conducted by a commercial strain of Saccharomyces cerevisiae. To ensure sufficient substrate was present, varying concentrations of apple pectin (up to 1.25 g/L for red wines and 1.00 g/L for white wine) were added at the start of fermentation. After bottling, trained panelists (n = 10) analyzed these wines for aroma, flavor, taste, and mouthfeel attributes. For both wines, significant interactions were noted between the presence of non-Saccharomyces yeasts and pectin addition which affected pH, titratable acidity, and concentrations of D-galacturonic acid. While no significant sensory differences were observed among the red wines, limited changes were noted for white wines. However, a strong positive correlation was found between the D-galacturonic acid and buttery aroma for Chardonnay and with flavor for Merlot. Increasing D-galacturonic acid concentrations, through utilization of non-Saccharomyces yeasts, may improve the wine quality as a buttery aroma is often associated with high-quality Chardonnay. For both red and white wines, the utilization of these particular non-Saccharomyces yeasts significantly influenced chemical properties but yielded minor sensory changes without any faults. PRACTICAL APPLICATION: With the recent trend to reduce alcohol content in commercial wines, the interest in non-Saccharomyces yeasts has grown. This study showed that the addition of non-Saccharomyces yeasts, perhaps due to their pectinase activity, influenced the chemical characteristics of red and white wines with limited sensory differences, making these yeasts a useful tool for winemakers to modify wine properties.

We define symmetries in non-relativistic quantum electrodynamics, which have the physical interpretation of rotation, parity and time reversal symmetry. We collect transformation properties related to these symmetries in Fock space representation as well as in the Schr\"odinger representation. As an application, we generalize and improve theorems about Kramer's degeneracy in non-relativistic quantum electrodynamics., Comment: 40 pages

A plethora of experimental studies manipulating plant diversity have shown a positive effect of biodiversity on ecosystem functions (aboveground biomass, microbial biomass etc.), which strengthens over time. Tightening of the interactions between plant and soil microorganisms over time is considered to be one of the mechanisms responsible for the observed strengthening of the biodiversity-ecosystem functioning (BEF) relationship. Belowground plant-microorganism interactions occur via the exchange of molecules present in the dissolved organic matter (DOM). Hence, an untargeted ultrahigh resolution mass spectrometric analysis of DOM provides an opportunity to understand the mechanisms of interaction between plants and microorganisms in soil. To investigate if and how plants-soil interactions changed over time, we took advantage of the highly replicated DBEF experiment of the Jena Experiment (JE) (Roscher et al., 2004, Vogel et al., 2019). In this experiment, the duration of plant-soil interactions (“history”) and the respective effects of plant diversity on ecosystem functioning were manipulated. Here, we analyzed the water extractable organic matter fraction of topsoil (WEOM; analogous to DOM in this study) using online nano solid phase extraction FTICR-mass spectrometry. While the molecular composition of the WEOM was not impacted by soil history, plant diversity effect differs among the soil history treatments. Specifically, plant diversity had a significant impact on the molecular composition of WEOM in treatments with plant and soils history. In addition, the molecular composition of WEOM in this treatment held a large number of molecular formulae that significantly correlated with plant diversity. This suggests that the strengthening of the biodiversity-ecosystem functioning over time is reflected in the WEOM molecular composition. Thus, the molecular composition of WEOM potentially provides insight into the mechanism underlying the strengthening of biodiversity-ecosystem functioning. Roscher, C., Schumacher, J., Baade, J., Wilcke, W., Gleixner, G., Weisser, W. W., ... & Schulze, E. D. (2004). The role of biodiversity for element cycling and trophic interactions: an experimental approach in a grassland community. Basic and Applied Ecology, 5(2), 107-121.Vogel, A., Ebeling, A., Gleixner, G., Roscher, C., Scheu, S., Ciobanu, M., ... & Eisenhauer, N. (2019). A new experimental approach to test why biodiversity effects strengthen as ecosystems age. In Advances in ecological research (Vol. 61, pp. 221-264). Academic Press.

Although representing only a small portion of all the organic matter being present in soils, dissolved organic matter (DOM) is its most mobile and reactive fraction. Along its transport down the soil profile, DOM interacts with minerals via sorption and aggregation phenomena, and with organisms via uptake, exudation or internal recycling. During this downward passage DOM composition changes too, shifting from a dominant plant/ plant decomposition product character to a more decomposer-driven signature. Such trends have been documented well by ultrahigh resolution mass spectrometry (FT-MS) which reveals thousands of molecular compositions (formulas) in one DOM sample (Roth et al. 2019). However, complementary properties of the molecules that constitute these signatures are largely missing. To test if the downward trend in molecular composition would also affect DOM’s fragmentation sensitivity, and if these effects could obscure the final ecological interpretation, we obtained direct injection FT-MS data with and without source-induced fragmentation (SID) at 45 eV. As a test dataset, we used samples from suction plates installed in three soil profiles (at 5, 10, 20, 30 and 60 cm depth) developed on aeolian sand deposits (podzols, cambisols) in Linde, Brandenburg (Germany). These three sites vary mainly in vegetation cover (grassland, oak, pine). All sites showed a clear depth trend as reported earlier, especially without SID turned on. SID clearly decreased the ion abundance of signals in the molecular weight range 300-500 Da (center ~350), while signals in the range 150-400 Da (center ~ 225) increased; more formulas were detected with SID on. With depth, the population of molecules decreasing/ increasing changed significantly, especially between 30 and 60 cm depth, across all sites. At 60 cm depth, decreasing formulas were more aliphatic while increasing formulas were more confined to a narrow area in the center of the van Krevelen space (“island of stability”). Interestingly, the formulas decreasing significantly across all sites were largely CHO (no other heteroatoms, at all depths), S-containing (at 5, 10, 20 and 30 cm) or P-containing (30 and 60 cm), while formulas increasing were CHO (at all depths) and N-containing ones (at all depths, but mainly at 20 and 30 cm), thereby indicating depth-dependent differences and ionization of new N-containing molecules. In ordination space, sites were clearly differentiated according to SID status, depth and site (in this order), but SID did not affect the separation in terms of depth or site, i.e., the ecological interpretation of DOM fingerprints remained similar independent of the SID status. This means that trends in soil DOM studies are likely not obscured by differences in fragmentation during the electrospray ionization process.Reference: Roth, V.-N., Lange, M., Simon, C., Hertkorn, N., Bucher, S., Goodall, T., Griffiths, R. I., Mellado-Vázquez, P. G., Mommer, L., Oram, N. J., Weigelt, A., Dittmar, T., Gleixner, G. (2019): Persistence of dissolved organic matter explained by molecular changes during its passage through soil. Nat. Geosci. 12: 755–761.

Above-ground material of members of the mint family is commercially distilled to extract essential oils, which are then formulated into a myriad of consumer products. Most of the research aimed at characterizing the processes involved in the formation of terpenoid oil constituents has focused on leaves. We now demonstrate, by investigating three mint species, peppermint (Mentha ˣ piperita L.), spearmint (Mentha spicata L.) and horsemint (Mentha longifolia (L.) Huds.; accessions CMEN 585 and CMEN 584), that other organs – namely stems, rhizomes and roots – also emit volatiles and that the terpenoid volatile composition of these organs can vary substantially from that of leaves, supporting the notion that substantial, currently underappreciated, chemical diversity exists. Differences in volatile quantities released by plants whose roots had been dipped in a Verticillium dahliae-spore suspension (experimental) or dipped in water (controls) were evident: increases of some volatiles in the root headspace of mint species that are susceptible to Verticillium wilt disease (peppermint and M. longifolia CMEN 584) were detected, while the quantities of certain volatiles decreased in rhizomes of species that show resistance to the disease (spearmint and M. longifolia CMEN 585). To address the genetic and biochemical basis underlying chemical diversity, we took advantage of the newly sequenced M. longifolia CMEN 585 genome to identify candidate genes putatively coding for monoterpene synthases (MTSs), the enzymes that catalyze the first committed step in the biosynthesis of monoterpenoid volatiles. The functions of these genes were established by heterologous expression in Escherichia coli, purification of the corresponding recombinant proteins, and enzyme assays, thereby establishing the existence of MTSs with activities to convert a common substrate, geranyl diphosphate, to (+)-α-terpineol, 1,8-cineole, γ-terpinene, and (–)-bornyl diphosphate, but were not active with other potential substrates. In conjunction with previously described MTSs that catalyze the formation of (–)-β-pinene and (–)-limonene, the product profiles of the MTSs identified here can explain the generation of all major monoterpene skeletons represented in the volatiles released by different mint organs.

The interactions between plants and soil microorganisms are fundamental for ecosystem functioning. However, it remains unclear if seasonality of plant growth impacts plant-microbial interactions, such as by inducing shifts in the microbial community composition, their biomass, or changes in the microbial uptake of plant-derived carbon. Here, we investigate the stability of microbial biomass of different functional groups and their net assimilation of plant-derived carbon over an entire growing season. Using a C3-C4 vegetation change experiment, and taking advantage of natural abundances of13C, we measured the plant-derived carbon in lipid biomarkers of soil microorganisms in rhizosphere and non-rhizosphere soil. We found that temporal and spatial stability was higher in bacterial than in fungal biomass, while the high temporal stability of all bacterial groups even increased in close proximity to roots. Moreover, differences in the association to plants, i.e., symbionts vs. free-living microorganisms, tend to determine the stability in the uptake of plant-derived carbon. Our results indicate, the inputs of plant-derived carbon over the growing season did not result in a shift in the microbial community composition, but instead, functional groups that are not in obligate symbiosis with plants showed a varying use of soil- and plant-derived carbon.

Ecosystem management aims at providing many ecosystem services simultaneously. Such ecosystem multifunctionality can be limited by trade-offs and increased by synergies among the underlying ecosystem functions (EF), which need to be understood to develop targeted management. Previous studies found differences in the correlation between EFs. We hypothesised that correlations between EFs are variable even under the controlled conditions of a field experiment and that seasonal and annual variation, plant species richness, and plot identity (identity effects of plant communities such as the presence and absence of functional groups and species) are drivers of these correlations. We used data on 31 EFs related to plants, consumers, and physical soil properties that were measured over 5 to 19 years, up to three times per year, in a temperate grassland experiment with 80 different plots, constituting six sown plant species richness levels (1, 2, 4, 8, 16, 60 species). We found that correlations between pairs of EFs were variable, and correlations between two particular EFs could range from weak to strong correlations or from negative to positive correlations among the repeated measurements. To determine the drivers of pairwise EF correlations, the covariance between EFs was partitioned into contributions from plant species richness, plot identity, and time (including years and seasons). We found that most of the covariance for synergies was explained by species richness (26.5%), whereas for trade-offs, most covariance was explained by plot identity (29.5%). Additionally, some EF pairs were more affected by differences among years and seasons and therefore showed a higher temporal variation. Therefore, correlations between two EFs from single measurements are insufficient to draw conclusions on trade-offs and synergies. Consequently, pairs of EFs need to be measured repeatedly under different conditions to describe their relationships with more certainty and be able to derive recommendations for the management of grasslands.

Extreme weather events are occurring more frequently, and research has shown that plant diversity can help mitigate impacts of climate change by increasing plant productivity and ecosystem stability1,2. Although soil temperature and its stability are key determinants of essential ecosystem processes related to water and nutrient uptake3as well as soil respiration and microbial activity4, no study has yet investigated whether plant diversity can buffer soil temperature fluctuations. Using 18 years of a continuous dataset with a resolution of 1 minute (∼795,312,000 individual measurements) from a large-scale grassland biodiversity experiment, we show that plant diversity buffers soil temperature throughout the year. Plant diversity helped to prevent soil heating in hot weather, and cooling in cold weather. Moreover, this effect of plant diversity increased over the 18-year observation period with the aging of experimental communities and was even stronger under extreme conditions, i.e., on hot days or in dry years. Using structural equation modelling, we found that plant diversity stabilized soil temperature by increasing soil organic carbon concentrations and, to a lesser extent, by increasing the plant leaf area index. We suggest that the diversity-induced stabilization of soil temperature may help to mitigate the negative effects of extreme climatic events such as soil carbon release, thus slow global warming.

Mercaptoethane sulfonate or coenzyme M (CoM) is the smallest known organic cofactor and is most commonly associated with the methane-forming step in all methanogenic archaea but is also associated with the anaerobic oxidation of methane to CO 2 in anaerobic methanotrophic archaea and the oxidation of short-chain alkanes in Syntrophoarchaeum species. It has also been found in a small number of bacteria capable of the metabolism of small organics. Although many of the steps for CoM biosynthesis in methanogenic archaea have been elucidated, a complete pathway for the biosynthesis of CoM in archaea or bacteria has not been reported. Here, we present the complete CoM biosynthesis pathway in bacteria, revealing distinct chemical steps relative to CoM biosynthesis in methanogenic archaea. The existence of different pathways represents a profound instance of convergent evolution. The five-step pathway involves the addition of sulfite, the elimination of phosphate, decarboxylation, thiolation, and the reduction to affect the sequential conversion of phosphoenolpyruvate to CoM. The salient features of the pathway demonstrate reactivities for members of large aspartase/fumarase and pyridoxal 5′-phosphate–dependent enzyme families.

Lewis base catalyzed allylations of C-centered nucleophiles have been largely limited to the niche substrates with acidic C-H substituted with C-F bonds at the stabilized carbanionic carbon. Here we report that the concept of latent pronucleophiles serves to overcome these limitations and allow for a variety of common silylated stabilized C-nucleophiles to undergo enantioselective allylations using allylic fluorides. The reactions of silyl enol ethers afford the allylation products in good yields and with high degree of regio / stereoselectivity as well as diastereoselectivity when cyclic silyl enol ethers are used. Further examples of silylated stabilized carbon nucleophiles that undergo efficient allylation speak in favor of the broad applicability of this concept in the arena of C-centered nucleophiles.

There is no doubt about the insect decline currently taking place in ecosystems with large anthropogenic impacts. Thus, there is a need for practices that avoid insect decline and or help to recover insect communities that have already suffered. Plant diversity has been shown to be positively related to insect abundance and diversity and to ecosystem functions provided by insects. However, it remains open if increased plant diversity can help to recover decreased populations. Here, we tested over one decade the effects of plant diversity on the carabid community in a large grassland biodiversity experiment and how plant diversity fostered the establishment of a natural grassland community after conversion of an arable field. There was a dramatic decline in carabid abundance from 2003, the first year after establishing the diversity experiment, to 2005. However, subsequently, the abundance increased constantly. One year after the land use change most individuals and species were those commonly found in agricultural fields. In subsequent years the community was dominated by grassland species. While plant diversity did not affect the abundance and richness of the carabid community, the turnover to a more native grassland community was accelerated by plant diversity in the first years after the land use change. In contrast, in later years plant diversity stabilized the community assemblage. Our study shows that high plant diversity can contribute to a faster transition of insect populations towards naturally occurring community assemblages and at later stages to more stabilized assemblages.

Relational accounts of risk explain variation in risk perception through situated cognitions defining risk as a relationship between “risk objects” and “objects at risk”. We extend this approach to include not only the relational constitution of cognitive risk objects, but also of the different actors assessing risk. Risk in this perspective is relational because it establishes a link between two different cognitive objects and between two (or more) actors. We argue that this is the case when at least two actors refer to a common risk object while retaining distinct objects at risk. We call this a constellation of risk entanglement across actors. We illustrate our theoretical arguments using data from 68 qualitative interviews and ethnographic fieldwork in the German finance-state nexus. Our analyses indicate how risk entanglement affects and transforms the fundamental logics according to which both of these fields operate.

Glandular trichomes (GTs) are epidermal structures that provide the first line of chemical defense against arthropod herbivores and other biotic threats. The most conspicuous structure on leaves of cultivated tomato (Solanum lycopersicum) is the type-VI GT (tVI-GT), which accumulates both flavonoids and volatile terpenoids. Although these classes of specialized metabolites are derived from distinct metabolic pathways, previous studies with a chalcone isomerase 1 (CHI1)-deficient mutant called anthocyanin free (af) showed that flavonoids are required for terpenoid accumulation in tVI-GTs. Here, we combined global transcriptomic and proteomic analyses of isolated trichomes as a starting point to show that the lack of CHI1 is associated with reduced levels of terpenoid biosynthetic transcripts and enzymes. The flavonoid deficiency in af trichomes also resulted in the upregulation of abiotic stress-responsive genes associated with DNA damage and repair. Several lines of biochemical and genetic evidence indicate that the terpenoid defect in af mutants is specific for the tVI-GT and is associated with the absence of bulk flavonoids rather than loss of CHI1 per se. A newly developed genome-scale model of metabolism in tomato tVI-GTs helped identify metabolic imbalances caused by the loss of flavonoid production. We provide evidence that flavonoid deficiency in this cell type leads to increased production of reactive oxygen species (ROS), which may impair terpenoid biosynthesis. Collectively, our findings support a role for flavonoids as ROS-scavenging antioxidants in GTs.

Following decades of tight restrictions, recent legislative adjustments have decriminalized the use of products derived from cannabis (Cannabis sativa L.) in many countries and jurisdictions. This has led to a renewed interest in better understanding the chemical basis of physiological effects attributed to cannabis use. The present review article summarizes our current knowledge regarding the 130 structures of cannabinoids that have been characterized from cannabis extracts to date. We are also providing information on the methods employed for structure determination to help the reader assess the quality of the original structural assignments. Cannabinoid chemical diversity is discussed in the context of current knowledge regarding the enzymes involved in cannabinoid biosynthesis. We briefly assess to what extent cannabinoid levels are determined by the genotype of a given chemovar and discuss the limits of enzymatic control over the cannabinoid profile.

Future climate scenarios indicate increasing drought intensity that threatens ecosystem functioning. However, the behavior of ecosystems during intense drought, such as the 2018 drought in Northern Europe, and their respective response following rewetting is not fully understood. We investigated the effect of drought on four different vegetation types in a temperate climate by analyzing dissolved organic matter (DOM) concentration and composition present in soil leachate, and compared it to two accompanying years. DOM is known to play an important role in ecosystem recovery and holds information on matter flows between plants, soil microorganisms and soil organic matter. Knowledge about DOM opens the possibility to better disentangle the role of plants and microorganisms in ecosystem recovery. We found that the average annual DOM concentration significantly decreased during the 2018 drought year compared to the normal year. This suggests a stimulation of DOM release under normal conditions, which include a summer drought followed by a rewetting period. The rewetting period, which holds high DOM concentrations, was suppressed under more intense drought. Our detailed molecular analysis of DOM using ultrahigh resolution mass spectrometry showed that DOM present at the beginning of the rewetting period resembles plant matter, whereas in later phases the DOM molecular composition was modified by microorganisms. We observed this pattern in all four vegetation types analyzed, although vegetation types differed in DOM concentration and composition. Our results suggest that plant matter drives ecosystem recovery and that increasing drought intensity may lower the potential for ecosystem recovery.

Aims We investigated the role of plants and their plant-derived carbon in shaping the microbial community that decomposes substrates and traced the return of nutrients from decomposition back to plant shoots in order to understand the importance of plants for ecosystem element cycling. Methods We performed a greenhouse experiment having plant communities with and without arbuscular mycorrhizal fungi (AMF) and ingrowth cores that held different 15N labeled substrates. We determined the microbial community structure using molecular sequencing and the net assimilation of plant carbon into soil microorganisms using a 13CO2 pulse and 13C measurements of microbial biomarkers. We determined the return of nitrogen back to the shoots using the 15N signal, which was provided from the decomposition of the substrate added to the ingrowth cores. Results We observed that the microbial community composition in the ingrowth cores and their net 13C assimilation depended on the presence of AMF and the added substrate. Both plant communities had similar 15N uptake into their shoots, but the net N uptake cost was significantly lower in presence of AMF. In the presence of AMF also lower net N uptake cost was observed for the decomposition of plant-derived and microorganism-derived substrates compared to inorganic nitrogen suggesting that AMF actively controls the decomposer comunity and their carbon demand. Conclusion Our results identify for the first time a functional overlap of soil microorganisms as identical substrate is decomposed by different microorganisms suggesting functional redundancy of microbial communities. In consequence a better understanding of ecosystem element cycling can only be achieved when the whole plant-microorganism-organic matter-soil continuum is investigated.

Mentha longifolia (L.) Huds., a wild, diploid mint species, has been developed as a model for mint genetic and genomic research to aid breeding efforts that target Verticillium wilt disease resistance and essential oil monoterpene composition. Here, we present a near-complete, chromosome-scale mint genome assembly for M. longifolia USDA accession CMEN 585. This new assembly is an update of a previously published genome draft, with dramatic improvements. A total of 42,107 protein-coding genes were annotated and placed on 12 chromosomal scaffolds. One hundred fifty-three genes contained conserved sequence domains consistent with nucleotide binding site-leucine-rich-repeat plant disease resistance genes. Homologs of genes implicated in Verticillium wilt resistance in other plant species were also identified. Multiple paralogs of genes putatively involved in p-menthane monoterpenoid biosynthesis were identified and several cases of gene clustering documented. Heterologous expression of candidate genes, purification of recombinant target proteins, and subsequent enzyme assays allowed us to identify the genes underlying the pathway that leads to the most abundant monoterpenoid volatiles. The bioinformatic and functional analyses presented here are laying the groundwork for using marker-assisted selection in improving disease resistance and essential oil traits in mints.

Three species of the genus

A large body of research shows that biodiversity loss can reduce ecosystem functioning. However, much of the evidence for this relationship is drawn from biodiversity-ecosystem functioning experiments in which biodiversity loss is simulated by randomly assembling communities of varying species diversity, and ecosystem functions are measured. This random assembly has led some ecologists to question the relevance of biodiversity experiments to real-world ecosystems, where community assembly or disassembly may be non-random and influenced by external drivers, such as climate, soil conditions or land use. Here, we compare data from real-world grassland plant communities with data from two of the largest and longest-running grassland biodiversity experiments (the Jena Experiment in Germany and BioDIV in the United States) in terms of their taxonomic, functional and phylogenetic diversity and functional-trait composition. We found that plant communities of biodiversity experiments cover almost all of the multivariate variation of the real-world communities, while also containing community types that are not currently observed in the real world. Moreover, they have greater variance in their compositional features than their real-world counterparts. We then re-analysed a subset of experimental data that included only ecologically realistic communities (that is, those comparable to real-world communities). For 10 out of 12 biodiversity-ecosystem functioning relationships, biodiversity effects did not differ significantly between the full dataset of biodiversity experiments and the ecologically realistic subset of experimental communities. Although we do not provide direct evidence for strong or consistent biodiversity-ecosystem functioning relationships in real-world communities, our results demonstrate that the results of biodiversity experiments are largely insensitive to the exclusion of unrealistic communities and that the conclusions drawn from biodiversity experiments are generally robust. By comparing data from real-world grassland communities with data from two of the longest-running grassland biodiversity-ecosystem functioning experiments, the authors show that conclusions derived from experimental systems are robust to the removal of unrealistic experimental communities., Nature Ecology & Evolution, 4 (11), ISSN:2397-334X

The use of latent nucleophiles, which are molecules that are not nucleophilic but can be activated to act as a nucleophile at an opportune time during the reaction, expands the scope of Lewis base catalyzed reactions. Here, we provide an overview of the concept and show examples of applications to N- and C-centered nucleophiles in allylic substitutions. N- and C-silyl compounds are superior latent (pro)nucleophiles in Lewis base catalyzed reactions with allylic fluorides in which the formation of the strong Si–F bond serves as the driving force for the reactions. The latent (pro)nucleophiles ensure high regio­selectivity in these reactions and enable enantioselective transformations of Morita–Baylis–Hillman adducts by the use of common chiral Lewis base catalysts.1 Introduction2 Substitution of MBH Carbonates3 The Concept of Latent (Pro)Nucleophiles4 Enantioselective Allylation of N-Heterocycles5 Enantioselective Phosphonyldifluoromethylation of Allylic Fluorides6 Conclusion

Monoterpene synthases catalyze the first committed step in the biosynthesis of monoterpenes and are in part responsible for the enormous structural diversity among this class of metabolites. Here, we explore the structure-function relationships underlying the formation of limonene enantiomers in limonene synthases that bind geranyl diphosphate as a common substrate. On the basis of analyses that consider both crystal structure data and amino acid sequence divergence, we identified candidate active site residues with potential roles in catalyzing reactions that involve accommodating reaction intermediates of opposite enantiomeric series. We demonstrate that spearmint (-)-limonene synthase [which generates99% (-)-limonene over (+)-limonene] can be converted into a mutant enzyme, by exchanging four residues (C321S, N345I, I453V, and M458V), which produces (+)-limonene with reversed enantiospecificity [80% (+)-limonene and 3% (-)-limonene; the remainder are mostly bicyclic monoterpenes]. This study provides the foundation for a more in-depth understanding of the formation of enantiomeric series of monoterpenes, which can have vastly different olfactory properties.

How do actors on financial markets transform the plethora of informational signals into concrete valuations of traded assets? How do they make decisions in an environment characterized by fundamental uncertainty? Although there is a rich tradition in economic sociology suggesting that emotions and other subjective factors play a decisive role in this regard, empirical studies of their relevance for economic action have remained rare. The present study seeks to fill this void. It investigates the emotional underpinnings of the practices of financial valuation in the German financial sector. Drawing on in-depth interviews with, and ethnographic observations of day traders and fund managers, the study shows that emotions are essential ingredients of their collective calculative practices. Results of the present study yield three empirically grounded key concepts that advance understanding of emotions in financial valuation: First, subjectively experienced market feelings enable traders and managers to imagine imminent market futures. Second, market sentiments reflect traders’ attributions of specific emotional qualities to financial markets and facilitate their understanding of market behaviour. Third, floor emotions are collective emotions in which traders become involved in organizations and on trading floors that help mitigate situational uncertainty.

Enantioenriched β-lactams are accessed via enantioselective allylation of anilines with Morita–Baylis–Hillman carbonates followed by a base-promoted cyclization. The resulting 3-methyleneazetidin-2-ones are amenable to diastereoselective functionalization to produce analogues of biologically active β-lactams. The use of nearly equimolar quantities of the starting materials make this method efficient and straightforward.

Drought is an ever-increasing threat; its negative effects on ecosystems and their functioning directly impact our food security. It is therefore critical to understand the mechanisms that affect drought resilience of ecosystems. Many ecosystem functions depend on plant-soil interactions and are mediated by dissolved organic molecules, which are then recorded in the dissolved organic carbon (DOC) that leaches from plants and soils. In particular, DOC properties during and after rewetting can reveal if and how ecosystems are affected by drought. We therefore investigated the concentration of DOC in four different plant communities on sandy soils in Germany over three years that differed in drought intensity, including the extreme 2018 drought. We also analysed the molecular composition of DOC using ultrahigh-resolution mass spectrometry to identify the carbon sources during the rewetting period. A linear mixed effect model revealed that drought intensity significantly affected DOC concentration. DOC concentration in soil leachate was slightly increased following medium drought intensity, but was significantly reduced following high drought intensity. This suggests that medium intensity drought may stimulate DOC release, however, high intensity drought reduces DOC release. Molecular composition analysis of the DOC present during the rewetting period revealed an initial release of plant-derived carbon followed by an increase in soil organic matter-like compounds. Our findings indicate that the initial release of plant-derived carbon into soil leachate might be crucial for the ability of ecosystems to quickly recover from drought. High intensity drought may interrupt plant functioning to the point of preventing the accumulation and subsequent release of plant-derived carbon during drought, and therefore hamper ecosystem recovery. This suggests the presence of tipping points with respect to the ability of ecosystems to recover from drought. As such, monitoring DOC concentrations could lead to better assessements of the drought resilience of ecosystems.

Crises such as European debt crisis, Brexit, and COVID-19 have challenged established relations between finance and the state in attempts at mitigating a broad range of crises-related risks. We ask whether and how these altered relations in themselves constitute novel uncertainties and risks between the two fields. To better understand these dynamics, we introduce the concept of "risk entanglement" to complement financialization as a key concept presently capturing these relations. Based on qualitative research in the German finance-state nexus, we show how financial and state actors mutually construe each other as risks that need to be managed and mitigated to safeguard their particular, field-specific logics and ends. We focus on systemic risk and political risk as two cases of risk entanglement: whereas systemic risk reflects the threat of a potential financial meltdown to the state, political risk reflects how the state endangers established risk practices in finance.

We consider the dynamics

For environmental, sustainable economic and political reasons, recycling processes are becoming increasingly important, aiming at a much higher use of secondary raw materials. Currently, for the copper and aluminium industries, no method for the non-destructive online analysis of heterogeneous materials are available. The Prompt Gamma Neutron Activation Analysis (PGNAA) has the potential to overcome this challenge. A difficulty when using PGNAA for online classification arises from the small amount of noisy data, due to short-term measurements. In this case, classical evaluation methods using detailed peak by peak analysis fail. Therefore, we propose to view spectral data as probability distributions. Then, we can classify material using maximum log-likelihood with respect to kernel density estimation and use discrete sampling to optimize hyperparameters. For measurements of pure aluminium alloys we achieve near perfect classification of aluminium alloys under 0.25 second., 8 pages, 12 figures, 1 table, published in the IEEE Transactions on Nuclear Science (TNS)

Digitalization leads to data transparency for production systems that we can benefit from with data-driven analysis methods like neural networks. For example, automated anomaly detection enables saving resources and optimizing the production. We study using rarely occurring information about labeled anomalies into Variational Autoencoder neural network structures to overcome information deficits of supervised and unsupervised approaches. This method outperforms all other models in terms of accuracy, precision, and recall. We evaluate the following methods: Principal Component Analysis, Isolation Forest, Classifying Neural Networks, and Variational Autoencoders on seven time series datasets to find the best performing detection methods. We extend this idea to include more infrequently occurring meta information about production processes. This use of sparse labels, both of anomalies or production data, allows to harness any additional information available for increasing anomaly detection performance.

Peppermint (Mentha x piperita L.) and Japanese catnip (Schizonepeta tenuifolia (Benth.) Briq.) accumulate p-menthane monoterpenoids with identical functionalization patterns but opposite stereochemistry. In the present study, we investigate the enantioselectivity of multiple enzymes involved in monoterpenoid biosynthesis in these species. Based on kinetic assays, mint limonene synthase, limonene 3-hydroxylase, isopiperitenol dehydrogenase, isopiperitenone reductase, and menthone reductase exhibited significant enantioselectivity toward intermediates of the pathway that proceeds through (-)-4S-limonene. Limonene synthase, isopiperitenol dehydrogenase and isopiperitenone reductase of Japanese catnip preferred intermediates of the pathway that involves (+)-4R-limonene, whereas limonene 3-hydroxylase was not enantioselective, and the activities of pulegone reductase and menthone reductase were too low to acquire meaningful kinetic data. Molecular modeling studies with docked ligands generally supported the experimental data obtained with peppermint enzymes, indicating that the preferred enantiomer was aligned well with the requisite cofactor and amino acid residues implicated in catalysis. A striking example for enantioselectivity was peppermint (-)-menthone reductase, which binds (-)-menthone with exquisite affinity but was predicted to bind (+)-menthone in a non-productive orientation that positions its carbonyl functional group at considerable distance to the NADPH cofactor. The work presented here lays the groundwork for structure-function studies aimed at unraveling how enantioselectivity evolved in closely related species of the Lamiaceae and beyond.

Pyrrolizidine alkaloids and their derivatives often feature interesting biological activities. A class of substituted 2,3-dihydro-1H-pyrrolizin-1-one derivatives has been explored as a potential treatment for Alzheimer's disease, but enantioselective synthesis of these molecules is still elusive. We report that enantioselective N-allylation of N-silyl pyrrole latent nucleophiles with allylic fluorides followed by hydrogenation and diastereoselective Friedel-Crafts cyclization constitute an efficient synthetic route to access enantioenriched substituted 2,3-dihydro-1H-pyrrolizin-1-ones.

Glandular trichomes are specialized anatomical structures that accumulate secretions with important biological roles in plant-environment interactions. These secretions also have commercial uses in the flavor, fragrance, and pharmaceutical industries. The capitate-stalked glandular trichomes of Cannabis sativa (cannabis), situated on the surfaces of the bracts of the female flowers, are the primary site for the biosynthesis and storage of resins rich in cannabinoids and terpenoids. In this study, we profiled nine commercial cannabis strains with purportedly different attributes, such as taste, color, smell, and genetic origin. Glandular trichomes were isolated from each of these strains, and cell type-specific transcriptome data sets were acquired. Cannabinoids and terpenoids were quantified in flower buds. Statistical analyses indicated that these data sets enable the high-resolution differentiation of strains by providing complementary information. Integrative analyses revealed a coexpression network of genes involved in the biosynthesis of both cannabinoids and terpenoids from imported precursors. Terpene synthase genes involved in the biosynthesis of the major monoterpenes and sesquiterpenes routinely assayed by cannabis testing laboratories were identified and functionally evaluated. In addition to cloning variants of previously characterized genes, specifically CsTPS14CT [(−)-limonene synthase] and CsTPS15CT (β-myrcene synthase), we functionally evaluated genes that encode enzymes with activities not previously described in cannabis, namely CsTPS18VF and CsTPS19BL (nerolidol/linalool synthases), CsTPS16CC (germacrene B synthase), and CsTPS20CT (hedycaryol synthase). This study lays the groundwork for developing a better understanding of the complex chemistry and biochemistry underlying resin accumulation across commercial cannabis strains.

The Mentha germplasm collection housed at the USDA National Clonal Germplasm Repository is a valuable source of diversity for genetic studies and mint breeding. We surveyed phenotypes and genotypes of accessions belonging to two species ancestral to commercial peppermint: M. aquatica and M. suaveolens. Morphology, ploidy, essential oil composition, and relative Verticillium wilt resistance were assessed. Genotyping with simple sequence repeat (SSR) markers was performed in order to establish a set of informative markers for distinguishing accessions from each other. M. suaveolens accessions were triploid or tetraploid, while M. aquatica accessions were octoploid or nonaploid. Holoploid genome sizes differed significantly among accessions within both species. Half of the M. aquatica accessions had (+)-menthofuran as the primary oil constituent, while other accessions showed atypical oil profiles. Most M. suaveolens accessions had high levels of either piperitenone oxide, (−)-carvone, or trans-piperitenone oxide. M. aquatica accessions showed a range of Verticillium wilt resistance to susceptibility, while most M. suaveolens accessions were highly wilt-resistant. Results from genotyping the accessions with nine SSR markers distinguished three groups: one mainly M. suaveolens, one mostly M. aquatica, and one with a mixture of the species. This study enables updates of accession descriptions in the Germplasm Resources Information Network database, and increases the utility of the Mentha collection to the research community.

The plant kingdom supports an extraordinary chemical diversity, with terpenoids representing a particularly diversified class of secondary (or specialized) metabolites. Volatile and semi-volatile terpenoids in the C10-C20 range are often formed in specialized cell types and secretory structures. In the angiosperm lineage, glandular trichomes play an important role in enabling the biosynthesis and storage (or in some cases secretion) of functionalized terpenoids. The 'decoration' of a terpenoid scaffold with functional groups changes its physical and chemical properties, and can therefore affect the perception of a specific metabolite by other organisms. Because of the ecological implications (e.g. plant-herbivore interactions) and commercial relevance (e.g. volatiles used in the flavor and fragrance industries), terpenoid functionalization has been researched extensively. Recent successes in the cloning and functional evaluation of genes as well as the structural and biochemical characterization of enzyme catalysts have laid the foundation for an improved understanding of how pathways toward functionalized monoterpenes may have evolved. In this review, we will focus on an up-to-date account of functionalization reactions present in glandular trichomes.

Land-use intensification is a major driver of biodiversity loss. However, understanding how different components of land use drive biodiversity loss requires the investigation of multiple trophic levels across spatial scales. Using data from 150 agricultural grasslands in central Europe, we assess the influence of multiple components of local- and landscape-level land use on more than 4,000 above- and belowground taxa, spanning 20 trophic groups. Plot-level land-use intensity is strongly and negatively associated with aboveground trophic groups, but positively or not associated with belowground trophic groups. Meanwhile, both above- and belowground trophic groups respond to landscape-level land use, but to different drivers: aboveground diversity of grasslands is promoted by diverse surrounding land-cover, while belowground diversity is positively related to a high permanent forest cover in the surrounding landscape. These results highlight a role of landscape-level land use in shaping belowground communities, and suggest that revised agroecosystem management strategies are needed to conserve whole-ecosystem biodiversity., Nature Communications, 12 (1), ISSN:2041-1723

The intensity and occurrence of droughts is projected to increase due to climate change. Dried soils release high concentrations of dissolved organic matter (DOM) into subsurface waters when they are rewet, the so-called rewetting peak. To more accurately predict the role of rewetting of soils after drought on the carbon cycle in a changing climate, it is important to understand the processes behind this DOM release.The DOM rewetting peak origin is disputed between soil organic matter (SOM) from breakdown of soil particles; accumulated root exudates; and microbial release due to a change in osmotic potential through osmolytes or cell bursting. To better understand the origin of the rewetting DOM peak, we took a rewetting series of soil water samples from different vegetation types between December 2018 and April 2019 for targeted and untargeted metabolomics. Initial results using untargeted ultrahigh-resolution mass spectrometry analysis revealed a clear temporal trend, indicating that vegetation-independent molecular changes occur following rewetting. An increase in O/C and a decrease in H/C over time was observed which is attributed to microbial decomposition, supported by a decrease in m/z over time. We also observed an increase in the content of lipidic compounds (R > 0.6) following rewetting. This indicates that cells do not burst upon rewetting and, over time, microbial activity increases, suggesting that the DOM rewetting peak is caused by a lack of decomposition, rather than a high production, of organic matter.

Die ontologische Auseinandersetzung an den drei Polen des Ungewissheitsarrangements wird nun um die gemeinsamen Wirksamkeiten, Verknupfungen und Verschrankungen von Affekt, Kalkulation und soziale Relationen erweitert. Grundsatzlich zu beantworten ist daher die Frage, wie diese drei Pole zur Hervorbringung von finanzwirtschaftlicher Praxis beitragen. Dies geschieht auf Basis der empirischen Einblicke in den deutschen Finanzmarkthandel und deren interpretativ-rekonstruktive Analyse.

In den folgenden Kapiteln wird untersucht, wie Affekt, Kalkulation und soziale Relation bei der Hervorbringung von finanzwirtschaftlicher Praxis und damit als praktische Begegnung des Zukunftsmoments wirksam werden. Gegenuber der theoretisch-konzeptuellen Arbeit vornehmlich an den drei Polen des Ungewissheitsarrangements, geraten nun empirisch vorfindbare und interpretativ-rekonstruierte Verknupfungen und Verschrankungen zwischen diesen Polen in den Blick. Hierfur wurde eine qualitative Untersuchung im deutschen Finanzsektor durchgefuhrt.

Der Anlass dieser Untersuchung fust auf der Wahrnehmung einer Krisenara kapitalistischer Dynamiken, die wesentlich von einer Involvierung finanzwirtschaftlicher Praxis gepragt ist. Hiervon ausgehend werden die Befunde der Untersuchung abschliesend diskutiert und verdichtet. Die damit verbundenen konkludierenden Ausfuhrungen zielen darauf ab, das Verstehenspotenzial des zukunftsbezogenen Zusammenspiels von Affekt, Kalkulation und sozialer Relation beim Finanzmarkthandel aufzuzeigen und damit den Beitrag fur soziologische Reflexionen des gegenwartigen Kapitalismus.