Integrating genomic and multiomic data for Angelica sinensis provides insights into the evolution and biosynthesis of pharmaceutically bioactive compounds

Angelica sinensis roots (Angelica roots) are rich in many bioactive compounds, including phthalides, coumarins, lignans, and terpenoids. However, the molecular bases for their biosynthesis are still poorly understood. Here, an improved chromosome-scale genome for A. sinensis var. Qinggui1 is reported, with a size of 2.16 Gb, contig N50 of 4.96 Mb and scaffold N50 of 198.27 Mb, covering 99.8% of the estimated genome. Additionally, by integrating genome sequencing, metabolomic profiling, and transcriptome analysis of normally growing and early-flowering Angelica roots that exhibit dramatically different metabolite profiles, the pathways and critical metabolic genes for the biosynthesis of these major bioactive components in Angelica roots have been deciphered. Multiomic analyses have also revealed the evolution and regulation of key metabolic genes for the biosynthesis of pharmaceutically bioactive components; in particular, TPSs for terpenoid volatiles, ACCs for malonyl CoA, PKSs for phthalide, and PTs for coumarin biosynthesis were expanded in the A. sinensis genome. These findings provide new insights into the biosynthesis of pharmaceutically important compounds in Angelica roots for exploration of synthetic biology and genetic improvement of herbal quality.

Heterologous Production of Artemisinin in Physcomitrium patens by Direct in vivo Assembly of Multiple DNA Fragments

The sesquiterpene lactone compound artemisinin is a natural medicinal product of commercial importance. This Artemisia annua-derived secondary metabolite is well known for its antimalarial activity and has been studied in several other biological assays. However, the major shortcoming in its production and commercialization is its low accumulation in the native plant. Moreover, the chemical synthesis of artemisinin is difficult and expensive due to its complex structure. Hence, an alternative and sustainable production system of artemisinin in a heterologous host is required. Previously, heterologous production of artemisinin was achieved by Agrobacterium-mediated transformation. However, this requires extensive bioengineering of modified Nicotiana plants. Recently, a technique involving direct in vivo assembly of multiple DNA fragments in the moss, P. patens, has been successfully established. We utilized this technique to engineer artemisinin biosynthetic pathway genes into the moss, and artemisinin was obtained without further modifications with high initial production. Here, we provide protocols for establishing moss culture accumulating artemisinin, including culture preparation, transformation method, and compound detection via HS-SPME, UPLC-MRM-MS, and LC-QTOF-MS. The bioengineering of moss opens up a more sustainable, cost effective, and scalable platform not only in artemisinin production but also other high-value specialized metabolites in the future.

Lipidomes of Icelandic bryophytes and screening of high contents of polyunsaturated fatty acids by using lipidomics approach

Bryophytes (mosses, liverworts, and hornworts) have interested researchers because of their high chemical diversity and their potential uses in pharmaceutical, food, and cosmetic industries. Specifically, long-chain polyunsaturated fatty acids (l-PUFA) such as arachidonic acid (AA) and eicosapentaenoic acid (EPA) are commonly found in bryophytes, but not in vascular plants. Bryophytes accumulate PUFAs in cold or even freezing temperature to keep the cell fluidity. Iceland has a long history of bryophyte vegetation. These bryophytes are highly adapted to the harsh environment in Iceland and therefore are expected to produce high amounts of PUFAs. However, despite the fact that hundreds of mosses and liverworts have been found in Iceland, their lipid profiles largely remain unknown. In this study, we performed untargeted lipidomics by using UPLC-ESI-QTOF-MS as a rapid screening strategy to examine the lipid compositions of 39 local bryophyte species in Iceland and aimed to find high AA and EPA producers. A total of 280 lipid molecular species from 15 lipid classes were quantified with isotope-labeled internal standards. AA and EPA were abundantly distributed in the phospholipids (mainly PC and PE) and glycerolipids (MGDG and DGDG) in six moss species, namely Racomotrium lanuginosum, R. ericoides, Bryum psedotriquetrium, Plagiomnium ellipticum, Hylocomium splendens, and Rhytidiadelphus triquetrus. Two of the six species (B. psedotriquetrium and H. splendens) also accumulated high concentrations of PUFA-containing-triacylglycerols.

Lipidomic analysis of moss species Bryum pseudotriquetrum and Physcomitrium patens under cold stress

Bryophytes, which lack lignin for protection, support themselves in harsh environments by producing various chemicals. In response to cold stress, lipids play a crucial role in cell adaptation and energy storage. Specifically, bryophytes survive at low temperatures by producing very long-chain polyunsaturated fatty acids (vl-PUFAs). The in-depth understanding of the lipid response to cold stress of bryophytes was studied by performing lipid profiling using ultra-high-performance liquid chromatography-quadrupole time of flight mass spectrometry (UHPLC-QTOF-MS). Two moss species (Bryum pseudotriquetrum and Physcomitrium patens) cultivated at 23°C and at 10°C were included in this study. Relative quantitative lipid concentrations were compared and the potential lipid biomarkers were identified by multivariate statistical analysis in each species. In B. pseudotriquetrum, it was observed that the phospholipids and glycolipids increased under cold stress, while storage lipids decreased. The accumulation of the lipids with high unsaturation degrees mostly appears in phospholipids and glycolipids for both mosses. The results also indicate that two unusual lipid classes in plants, sulfonolipids and phosphatidylmethanol are biosynthesized by the bryophytes. This has not been seen previously and show that bryophytes have a very diverse chemistry and substantially different from other plant groups.

Effects of extraction parameters on lipid profiling of mosses using UPLC-ESI-QTOF-MS and multivariate data analysis

INTRODUCTION

Non-target lipid profiling by using ultra-performance liquid chromatography coupled to electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOF-MS) has been used extensively in the past decades in plant studies. However, the lipidomes of bryophytes have only been scarcely studied, although they are the second largest group in plant kingdom.

OBJECTIVES

We evaluated the effects of different cell disruption methods (no disruption, shake, ultrasound, and bead beating), and storage conditions (air-dried, freeze-dried, and fresh frozen) of five moss species (including Racomitrium lanuginosum B and D, Philonotis fontana, Sphagnum teres, and Hylocomium splendens).

METHODS

The lipid profiling results of each extraction parameter were analyzed by using multivariate data analysis including unsupervised principal component analysis and supervised orthogonal projections to latent structures discriminant analysis.

RESULTS

The results showed that extraction with bead beating resulted in the highest lipid content and the most detected features, but these were caused by the contamination from plastic tubes. Minor lipid metabolite changes were found in shaking and ultrasonication methods when compared with no disruption method. Significant amounts of phosphatidylcholine, diacylglyceryltrimethylhomoserine and their lyso lipids were observed in air-dried moss tissues, whereas diacylglycerol, triacylglycerol and ceramide were mostly exclusively detected when fresh frozen tissues were used for extraction.

CONCLUSION

We concluded that lipid extraction using fresh frozen samples with ultrasound assistance provide the most original lipid composition and gave a relatively high lipid content.

Collagenase and Tyrosinase Inhibitory Effect of Isolated Constituents from the Moss Polytrichum formosum

Mosses from the genus Polytrichum have been shown to contain rare benzonaphthoxanthenones compounds, and many of these have been reported to have important biological activities. In this study, extracts from Polytrichum formosum were analyzed in vitro for their inhibitory properties on collagenase and tyrosinase activity, two important cosmetic target enzymes involved respectively in skin aging and pigmentation. The 70% ethanol extract showed a dose-dependent inhibitory effect against collagenase (IC₅₀ = 4.65 mg/mL). The methanol extract showed a mild inhibitory effect of 44% against tyrosinase at 5.33 mg/mL. Both extracts were investigated to find the constituents having a specific affinity to the enzyme targets collagenase and tyrosinase. The known compounds ohioensin A (1), ohioensin C (3), and communin B (4), together with nor-ohioensin D (2), a new benzonaphthoxanthenone, were isolated from P. formosum. Their structures were determined by mass spectrometry and NMR spectroscopy. Compounds 1 (IC₅₀ = 71.99 µM) and 2 (IC₅₀ = 167.33 µM) showed inhibitory activity against collagenase. Compound 1 also exhibited inhibition of 30% against tyrosinase activity at 200 µM. The binding mode of the active compounds was theoretically generated by an in-silico approach against the 3D structures of collagenase and tyrosinase. These current results present the potential application from the moss P. formosum as a new natural source of collagenase and tyrosinase inhibitors.

Bio-Guided Fractionation and Molecular Networking Reveal Fatty Acids to Be Principal Anti-Parasitic Compounds in Nordic Seaweeds

Widespread use of antimicrobial drugs has led to high levels of drug-resistance in pathogen populations and a need for novel sources of anti-bacterial and anti-parasitic compounds. Macroalgae (seaweed) are potentially a rich source of bioactive compounds, and several species have traditionally been used as vermifuges. Here, we investigated the anti-parasitic properties of four common cold-water Nordic seaweeds; Palmaria palmata (Rhodophyta), Laminaria digitata, Saccharina latissima and Ascophyllum nodosum (Ochrophyta, Phaeophyceae). Screening of organic extracts against helminths of swine (Ascaris suum) and sheep (Teladorsagia circumcincta) revealed that S. latissima and L. digitata had particularly high biological activity. A combination of molecular networking and bio-guided fractionation led to the isolation of six compounds from extracts of these two species identified in both fermented and non-fermented samples. The six isolated compounds were tentatively identified by using MS-FINDER as five fatty acids and one monoglyceride: Stearidonic acid (1), Eicosapentaenoic acid (2), Alpha-Linolenic acid (3), Docosahexaenoic acid (4), Arachidonic acid (5), and Monoacylglycerol (MG 20:5) (6). Individual compounds showed only modest activity against A. suum, but a clear synergistic effect was apparent when selected compounds were tested in combination. Collectively, our data reveal that fatty acids may have a previously unappreciated role as natural anti-parasitic compounds, which suggests that seaweed products may represent a viable option for control of intestinal helminth infections.

Cellulase and Macerozyme-PEG-mediated Transformation of Moss Protoplasts

This protocol describes the generation of protoplasts from protonemal tissue of the moss Physcomitrium patens (syn. Physcomitrella patens), using Cellulase ONOZUKA R10 and Macerozyme R10, followed by polyethylene glycol (PEG) mediated transformation. The protonemal tissue grown in liquid suspension was harvested and treated with enzyme cocktails mix of 1.5% Cellulase ONOZUKA R10 and 0.5% Macerozyme R10 to generate 1,8 million protoplasts within 3 h.

From Plant to Patient: Thapsigargin, a Tool for Understanding Natural Product Chemistry, Total Syntheses, Biosynthesis, Taxonomy, ATPases, Cell Death, and Drug Development

Thapsigargin, the first representative of the hexaoxygenated guaianolides, was isolated 40 years ago in order to understand the skin-irritant principles of the resin of the umbelliferous plant Thapsia garganica. The pronounced cytotoxicity of thapsigargin is caused by highly selective inhibition of the intracellular sarco-endoplasmic Ca²⁺-ATPase (SERCA) situated on the membrane of the endo- or sarcoplasmic reticulum. Thapsigargin is selective to the SERCA pump and to a minor extent the secretory pathway Ca²⁺/Mn²⁺ ATPase (SPCA) pump. Thapsigargin has become a tool for investigation of the importance of SERCA in intracellular calcium homeostasis. In addition, complex formation of thapsigargin with SERCA has enabled crystallization and structure determination of calcium-free states by X-ray crystallography. These results led to descriptions of the mechanism of action and kinetic properties of SERCA and other ATPases. Inhibition of SERCA depletes Ca²⁺ from the sarco- and endoplasmic reticulum provoking the unfolded protein response, and thereby has enabled new studies on the mechanism of cell death. Development of protocols for selective transformation of thapsigargin disclosed the chemistry and facilitated total synthesis of the molecule. Conversion of trilobolide into thapsigargin offered an economically feasible sustainable source of thapsigargin, which enables a future drug production. Principles for prodrug development were used by conjugating a payload derived from thapsigargin with a hydrophilic peptide selectively cleaved by proteases in the tumor. Mipsagargin was developed in order to obtain a drug for treatment of cancer diseases characterized by the presence of prostate specific membrane antigen (PSMA) in the neovascular tissue of the tumors. Even though mipsagargin showed interesting clinical effects the results did not encourage funding and consequently the attempt to register the drug has been abandoned. In spite of this disappointing fact, the research performed to develop the drug has resulted in important scientific discoveries concerning the chemistry, biosynthesis and biochemistry of sesquiterpene lactones, the mechanism of action of ATPases including SERCA, mechanisms for cell death caused by the unfolded protein response, and the use of prodrugs for cancer-targeting cytotoxins. The presence of toxins in only some species belonging to Thapsia also led to a major revision of the taxonomy of the genus.

Connecting moss lipid droplets to patchoulol biosynthesis

Plant-derived terpenoids are extensively used in perfume, food, cosmetic and pharmaceutical industries, and several attempts are being made to produce terpenes in heterologous hosts. Native hosts have evolved to accumulate large quantities of terpenes in specialized cells. However, heterologous cells lack the capacity needed to produce and store high amounts of non-native terpenes, leading to reduced growth and loss of volatile terpenes by evaporation. Here, we describe how to direct the sesquiterpene patchoulol production into cytoplasmic lipid droplets (LDs) in Physcomitrium patens (syn. Physcomitrella patens), by attaching patchoulol synthase (PTS) to proteins linked to plant LD biogenesis. Three different LD-proteins: Oleosin (PpOLE1), Lipid Droplet Associated Protein (AtLDAP1) and Seipin (PpSeipin325) were tested as anchors. Ectopic expression of PTS increased the number and size of LDs, implying an unknown mechanism between heterologous terpene production and LD biogenesis. The expression of PTS physically linked to Seipin increased the LD size and the retention of patchoulol in the cell. Overall, the expression of PTS was lower in the anchored mutants than in the control, but when normalized to the expression the production of patchoulol was higher in the seipin-linked mutants.

Exploring evolutionary theories of plant defence investment using field populations of the deadly carrot

BACKGROUND AND AIMS

There are a number of disparate models predicting variation in plant chemical defences between species, and within a single species over space and time. These can give conflicting predictions. Here we review a number of these theories, before assessing their power to predict the spatial-temporal variation of thapsigargins between and within populations of the deadly carrot (Thapsia garganica). By utilizing multiple models simultaneously (optimum defence theory, growth rate hypothesis, growth-differentiation balance hypothesis, intra-specific framework and resource exchange model of plant defence), we will highlight gaps in their predictions and evaluate the performance of each.

METHODS

Thapsigargins are potent anti-herbivore compounds that occur in limited richness across the different plant tissues of T. garganica, and therefore represent an ideal system for exploring these models. Thapsia garganica plants were collected from six locations on the island of Ibiza, Spain, and the thapsigargins quantified within reproductive, vegetative and below-ground tissues. The effects of sampling time, location, mammalian herbivory, soil nutrition and changing root-associated fungal communities on the concentrations of thapsigargins within these in situ observations were analysed, and the results were compared with our model predictions.

KEY RESULTS

The models performed well in predicting the general defence strategy of T. garganica and the above-ground distribution of thapsigargins, but failed to predict the considerable proportion of defences found below ground. Models predicting variation over environmental gradients gave conflicting and less specific predictions, with intraspecific variation remaining less understood.

CONCLUSION

Here we found that multiple models predicting the general defence strategy of plant species could likely be integrated into a single model, while also finding a clear need to better incorporate below-ground defences into models of plant chemical defences. We found that constitutive and induced thapsigargins differed in their regulation, and suggest that models predicting intraspecific defences should consider them separately. Finally, we suggest that in situ studies be supplemented with experiments in controlled environments to identify specific environmental parameters that regulate variation in defences within species.

Stabilization of dhurrin biosynthetic enzymes from Sorghum bicolor using a natural deep eutectic solvent

In recent years, ionic liquids and deep eutectic solvents (DESs) have gained increasing attention due to their ability to extract and solubilize metabolites and biopolymers in quantities far beyond their solubility in oil and water. The hypothesis that naturally occurring metabolites are able to form a natural deep eutectic solvent (NADES), thereby constituting a third intracellular phase in addition to the aqueous and lipid phases, has prompted researchers to study the role of NADES in living systems. As an excellent solvent for specialized metabolites, formation of NADES in response to dehydration of plant cells could provide an appropriate environment for the functional storage of enzymes during drought. Using the enzymes catalyzing the biosynthesis of the defense compound dhurrin as an experimental model system, we demonstrate that enzymes involved in this pathway exhibit increased stability in NADES compared with aqueous buffer solutions, and that enzyme activity is restored upon rehydration. Inspired by nature, application of NADES provides a biotechnological approach for long-term storage of entire biosynthetic pathways including membrane-anchored enzymes.

Valuable Fatty Acids in Bryophytes-Production, Biosynthesis, Analysis and Applications

Bryophytes (mosses, liverworts and hornworts) often produce high amounts of very long-chain polyunsaturated fatty acids (vl-PUFAs) including arachidonic acid (AA, 20:4 Δ5,8,11,14) and eicosapentaenoic acid (EPA, 20:5 Δ5,8,11,14,17). The presence of vl-PUFAs is common for marine organisms such as algae, but rarely found in higher plants. This could indicate that bryophytes did not lose their marine origin completely when they landed into the non-aqueous environment. Vl-PUFA, especially the omega-3 fatty acid EPA, is essential in human diet for its benefits on healthy brain development and inflammation modulation. Recent studies are committed to finding new sources of vl-PUFAs instead of fish and algae oil. In this review, we summarize the fatty acid compositions and contents in the previous studies, as well as the approaches for qualification and quantification. We also conclude different approaches to enhance AA and EPA productions including biotic and abiotic stresses.

Biosynthesis of tovarol and other sesquiterpenoids in Thapsia laciniata Rouy

The genus Thapsia produces a wide variety of sesquiterpenoids. The Mediterranean plant Thapsia laciniata Rouy is known to have a product profile that differs from several other species in the genus. Thus, the biosynthesis of sesquiterpenoids in Thapsia laciniata Rouy was investigated. Here we describe three terpene synthases, TlTPS820, TlTPS509 and TlTPS18983. TlTPS18983 is a multi-product enzyme with farnesene as the major product, while TlTPS509 produces guaiol and bulnesol along with other major and several minor unknown products. TlTPS820 is orthologous to TgTPS2 from Thapsia garganica L. and is an epikunzeaol synthase. TgCYP76AE2 from Thapsia garganica performs a triple hydroxylation of epikunzeaol at C-12 to make dihydrocostunolide. It was therefore investigated if the cytochrome P450, TlCYP76AE4 was able to use epikunzeaol as a substrate. It was found that TlCYP76AE4 hydroxylates epikunzeaol at C-8 to yield tovarol instead of dihydrocostunolide.

Physcomitrella patens, a versatile synthetic biology chassis

During three decades the moss Physcomitrella patens has been developed to a superb green cell factory with the first commercial products on the market. In the past three decades the moss P. patens has been developed from an obscure bryophyte to a model organism in basic biology, biotechnology, and synthetic biology. Some of the key features of this system include a wide range of Omics technologies, precise genome-engineering via homologous recombination with yeast-like efficiency, a certified good-manufacturing-practice production in bioreactors, successful upscaling to 500 L wave reactors, excellent homogeneity of protein products, superb product stability from batch-to-batch, and a reliable procedure for cryopreservation of cell lines in a master cell bank. About a dozen human proteins are being produced in P. patens as potential biopharmaceuticals, some of them are not only similar to their animal-produced counterparts, but are real biobetters with superior performance. A moss-made pharmaceutical successfully passed phase 1 clinical trials, a fragrant moss, and a cosmetic moss-product is already on the market, highlighting the economic potential of this synthetic biology chassis. Here, we focus on the features of mosses as versatile cell factories for synthetic biology and their impact on metabolic engineering.

Use of a temporary immersion bioreactor system for the sustainable production of thapsigargin in shoot cultures of Thapsia garganica

BACKGROUND

Thapsigargin and nortrilobolide are sesquiterpene lactones found in the Mediterranean plant Thapsia garganica L. Thapsigargin is a potent inhibitor of the sarco/endoplasmic reticulum calcium ATPase pump, inducing apoptosis in mammalian cells. This mechanism has been used to develop a thapsigargin-based cancer drug first by GenSpera and later Inspyr Therapeutics (Westlake Village, California). However, a stable production of thapsigargin is not established.

RESULTS

In vitro regeneration from leaf explants, shoot multiplication and rooting of T. garganica was obtained along with the production of thapsigargins in temporary immersion bioreactors (TIBs). Thapsigargin production was enhanced using reduced nutrient supply in combination with methyl jasmonate elicitation treatments. Shoots grown in vitro were able to produce 0.34% and 2.1% dry weight of thapsigargin and nortrilobolide, respectively, while leaves and stems of wild T. garganica plants contain only between 0.1 and 0.5% of thapsigargin and below detectable levels of nortrilobolide. In addition, a real-time reverse transcription PCR (qRT-PCR) study was performed to study the regulatory role of the biosynthetic genes HMG-CoA reductase (HMGR), farnesyl diphosphate synthase (FPPS), epikunzeaol synthase (TgTPS2) and the cytochrome P450 (TgCYP76AE2) of stem, leaf and callus tissues. Nadi staining showed that the thapsigargins are located in secretory ducts within these tissues.

CONCLUSIONS

Shoot regeneration, rooting and biomass growth from leaf explants of T. garganica were achieved, together with a high yield in vitro production of thapsigargin in TIBs.

Stable Production of the Antimalarial Drug Artemisinin in the Moss Physcomitrella patens

Malaria is a real and constant danger to nearly half of the world's population of 7.4 billion people. In 2015, 212 million cases were reported along with 429,000 estimated deaths. The World Health Organization recommends artemisinin-based combinatorial therapies, and the artemisinin for this purpose is mainly isolated from the plant Artemisia annua. However, the plant supply of artemisinin is irregular, leading to fluctuation in prices. Here, we report the development of a simple, sustainable, and scalable production platform of artemisinin. The five genes involved in artemisinin biosynthesis were engineered into the moss Physcomitrella patens via direct in vivo assembly of multiple DNA fragments. In vivo biosynthesis of artemisinin was obtained without further modifications. A high initial production of 0.21 mg/g dry weight artemisinin was observed after only 3 days of cultivation. Our study shows that P. patens can be a sustainable and efficient production platform of artemisinin that without further modifications allow for industrial-scale production. A stable supply of artemisinin will lower the price of artemisinin-based treatments, hence become more affordable to the lower income communities most affected by malaria; an important step toward containment of this deadly disease threatening millions every year.

Localization and in-Vivo Characterization of Thapsia garganica CYP76AE2 Indicates a Role in Thapsigargin Biosynthesis

The Mediterranean plant Thapsia garganica (dicot, Apiaceae), also known as deadly carrot, produces the highly toxic compound thapsigargin. This compound is a potent inhibitor of the sarcoplasmic-endoplasmic reticulum Ca2+-ATPase calcium pump in mammals and is of industrial importance as the active moiety of the anticancer drug mipsagargin, currently in clinical trials. Knowledge of thapsigargin in planta storage and biosynthesis has been limited. Here, we present the putative second step in thapsigargin biosynthesis, by showing that the cytochrome P450 TgCYP76AE2, transiently expressed in Nicotiana benthamiana, converts epikunzeaol into epidihydrocostunolide. Furthermore, we show that thapsigargin is likely to be stored in secretory ducts in the roots. Transcripts from TgTPS2 (epikunzeaol synthase) and TgCYP76AE2 in roots were found only in the epithelial cells lining these secretory ducts. This emphasizes the involvement of these cells in the biosynthesis of thapsigargin. This study paves the way for further studies of thapsigargin biosynthesis.

Insight into Biochemical Characterization of Plant Sesquiterpene Synthases

A fast and reproducible protocol was established for enzymatic characterization of plant sesquiterpene synthases that can incorporate radioactivity in their products. The method utilizes the 96-well format in conjunction with cluster tubes and enables processing of >200 samples a day. Along with reduced reagent usage, it allows further reduction in the use of radioactive isotopes and flammable organic solvents. The sesquiterpene synthases previously characterized were expressed in yeast, and the plant-derived Thapsia garganica kunzeaol synthase TgTPS2 was tested in this method. K_M for TgTPS2 was found to be 0.55 μM; the turnover number, k_cat, was found to be 0.29 s⁻¹, k_cat for TgTPS2 is in agreement with that of terpene synthases of other plants, and k_cat/K_M was found to be 0.53 s⁻¹ μM⁻¹ for TgTPS2. The kinetic parameters were in agreement with previously published data.

Role of the Colletotrichum acutatum sesquiterpene synthase CaTPS in the biosynthesis of sesquiterpenoids

Colletotrichum acutatum is a major fungal pathogen of fruit crops, which causes severe yield losses in strawberry production. A potential key factor in plant-pathogen interactions is fungal sesquiterpenoids which have mycotoxic and phytotoxic activities. The first committed step in sesquiterpenoid biosynthesis is performed by sesquiterpene synthases (TPS). Only a few TPSs have been functionally characterized from filamentous fungi and none from the genus Colletotrichum. Despite being an important fungal pathogen to agriculture, it is poorly understood at the molecular and chemical levels. The terpenoid biochemistry in Coll. acutatum strain SA 0-1 was studied and one Coll. acutatum TPS (CaTPS) was successfully cloned and characterized in yeast. CaTPS catalyses the biosynthesis of multiple sesquiterpenoids. The two major products are β-caryophyllene and an unidentified sesquiterpenoid along with α-humulene as one of the minor sesquiterpenoid products. These products were also secreted by the fungus in strawberry fruit medium along with several other sesquiterpenoids indicating other TPSs are active during in vitro growth. β-Caryophyllene and α-humulene are known cytotoxic products important for ecological interactions and are produced by SA 0-1. Interestingly, a gene expression analysis using quantitative real-time PCR revealed a significant increase in expression of CaTPS during strawberry fruit infection, thus indicating that it could be involved in fruit infection. This is, we believe, the first characterization of TPS in Colletotrichum spp. and terpenoid profiles of Coll. acutatum, which could facilitate studies on the role of terpenoids in the ecology of Coll. acutatum.

The decision to germinate is regulated by divergent molecular networks in spores and seeds

Dispersal is a key step in land plant life cycles, usually via formation of spores or seeds. Regulation of spore- or seed-germination allows control over the timing of transition from one generation to the next, enabling plant dispersal. A combination of environmental and genetic factors determines when seed germination occurs. Endogenous hormones mediate this decision in response to the environment. Less is known about how spore germination is controlled in earlier-evolving nonseed plants. Here, we present an in-depth analysis of the environmental and hormonal regulation of spore germination in the model bryophyte Physcomitrella patens (Aphanoregma patens). Our data suggest that the environmental signals regulating germination are conserved, but also that downstream hormone integration pathways mediating these responses in seeds were acquired after the evolution of the bryophyte lineage. Moreover, the role of abscisic acid and diterpenes (gibberellins) in germination assumed much greater importance as land plant evolution progressed. We conclude that the endogenous hormone signalling networks mediating germination in response to the environment may have evolved independently in spores and seeds. This paves the way for future research about how the mechanisms of plant dispersal on land evolved.

Evolutionary prediction of medicinal properties in the genus Euphorbia L

The current decrease of new drugs brought to the market has fostered renewed interest in plant-based drug discovery. Given the alarming rate of biodiversity loss, systematic methodologies in finding new plant-derived drugs are urgently needed. Medicinal uses of plants were proposed as proxy for bioactivity, and phylogenetic patterns in medicinal plant uses have suggested that phylogeny can be used as predictive tool. However, the common practice of grouping medicinal plant uses into standardised categories may restrict the relevance of phylogenetic predictions. Standardised categories are mostly associated to systems of the human body and only poorly reflect biological responses to the treatment. Here we show that medicinal plant uses interpreted from a perspective of a biological response can reveal different phylogenetic patterns of presumed underlying bioactivity compared to standardised methods of medicinal plant use classification. In the cosmopolitan and pharmaceutically highly relevant genus Euphorbia L., identifying plant uses modulating the inflammatory response highlighted a greater phylogenetic diversity and number of potentially promising species than standardised categories. Our interpretation of medicinal plant uses may therefore allow for a more targeted approach for future phylogeny-guided drug discovery at an early screening stage, which will likely result in higher discovery rates of novel chemistry with functional biological activity.

Two key polymorphisms in a newly discovered allele of the Vitis vinifera TPS24 gene are responsible for the production of the rotundone precursor α-guaiene

Rotundone was initially identified as a grape-derived compound responsible for the peppery aroma of Shiraz wine varieties. It has subsequently been found in black and white pepper and several other spices. Because of its potent aroma, the molecular basis for rotundone formation is of particular relevance to grape and wine scientists and industry. We have identified and functionally characterized in planta a sesquiterpene synthase, VvGuaS, from developing grape berries, and have demonstrated that it produces the precursor of rotundone, α-guaiene, as its main product. The VvGuaS enzyme is a novel allele of the sesquiterpene synthase gene, VvTPS24, which has previously been reported to encode VvPNSeInt, an enzyme that produces a variety of selinene-type sesquiterpenes. This newly discovered VvTPS24 allele encodes an enzyme 99.5% identical to VvPNSeInt, with the differences comprising just 6 out of the 561 amino acid residues. Molecular modelling of the enzymes revealed that two of these residues, T414 and V530, are located in the active site of VvGuaS within 4 Å of the binding-site of the substrate, farnesyl pyrophosphate. Mutation of these two residues of VvGuaS into the corresponding polymorphisms in VvPNSeInt results in a complete functional conversion of one enzyme into the other, while mutation of each residue individually produces an intermediate change in the product profile. We have therefore demonstrated that VvGuaS, an enzyme responsible for production of the rotundone precursor, α-guaiene, is encoded by a novel allele of the previously characterized grapevine gene VvTPS24 and that two specific polymorphisms are responsible for functional differences between VvTPS24 alleles.

Global medicinal uses of Euphorbia L. (Euphorbiaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Euphorbia (spurges, Euphorbiaceae) is the third largest genus of flowering plants, with almost 2000 species. Its exceptional diversity of growth forms and near-cosmopolitan distribution have attracted human interest since ancient times. For instance in Australia, topical application of latex of Euphorbia peplus L. is used as a home treatment for skin cancer and actinic keratosis. Its use in Australian folk medicine has inspired the release of the drug Picato® (ingenol mebutate), and further fostered interest in natural products and medicinal uses of Euphorbia in recent years.

AIM OF THE STUDY

To provide an indicative overview of medicinal uses of the genus Euphorbia driven by the recent interest in biologically active natural products from Euphorbia in drug discovery. We assess documented medicinal knowledge and value of the genus Euphorbia and the taxonomic distribution of this value.

MATERIALS AND METHODS

We undertook an extensive survey of over 260 multidisciplinary publications on the online repository JSTOR using the search term "Euphorbia medicinal".

RESULTS

Medicinal uses were identified for >5% of the species in the genus, including descriptions of treatments for a variety of diseases. The most-cited medicinal uses around the world were treatments for digestive system disorders, skin ailments and, especially in the Southern hemisphere, infections. Consensus ratios indicated that the most-valued medicinal uses of Euphorbia species are in the treatment of digestive and respiratory complaints, inflammation and injuries, especially by members of Euphorbia subg. Chamaesyce.

CONCLUSIONS

The present study gives a first indicative overview of Euphorbia species used for health and wellbeing around the world. The exceptional diversity of the genus Euphorbia is not only represented by its growth forms but also by its diverse medicinal uses. Our results highlight the importance of research into medicinal uses of Euphorbia species and their importance as a source of natural products. Furthermore the medicinally highly valuable subgenus Chamaesyce was identified as chemically under-investigated, emphasizing the need for further studies investigating the chemical diversity to which the high medicinal value of Euphorbia subg. Chamaesyce can be attributed.

Additional diterpenes from Physcomitrella patens synthesized by copalyl diphosphate/kaurene synthase (PpCPS/KS)

The bifunctional diterpene synthase, copalyl diphosphate/kaurene synthase from the moss Physcomitrella patens (PpCPS/KS), catalyses the formation of at least four diterpenes, including ent-beyerene, ent-sandaracopimaradiene, ent-kaur-16-ene, and 16-hydroxy-ent-kaurene. The enzymatic activity has been confirmed through generation of a targeted PpCPS/KS knock-out mutant in P. patens via homologous recombination, through transient expression of PpCPS/KS in Nicotiana benthamiana, and expression of PpCPS/KS in E. coli. GC-MS analysis of the knock-out mutant shows that it lacks the diterpenoids, supporting that all are products of PpCPS/KS as observed in N. benthamiana and E. coli. These results provide additional knowledge of the mechanism of this bifunctional diterpene synthase, and are in line with proposed reaction mechanisms in kaurene biosynthesis.

Evolution of substrate recognition sites (SRSs) in cytochromes P450 from Apiaceae exemplified by the CYP71AJ subfamily

BACKGROUND

Large proliferations of cytochrome P450 encoding genes resulting from gene duplications can be termed as 'blooms', providing genetic material for the genesis and evolution of biosynthetic pathways. Furanocoumarins are allelochemicals produced by many of the species in Apiaceaous plants belonging to the Apioideae subfamily of Apiaceae and have been described as being involved in the defence reaction against phytophageous insects.

RESULTS

A bloom in the cytochromes P450 CYP71AJ subfamily has been identified, showing at least 2 clades and 6 subclades within the CYP71AJ subfamily. Two of the subclades were functionally assigned to the biosynthesis of furanocoumarins. Six substrate recognition sites (SRS1-6) important for the enzymatic conversion were investigated in the described cytochromes P450 and display significant variability within the CYP71AJ subfamily. Homology models underline a significant modification of the accession to the iron atom, which might explain the difference of the substrate specificity between the cytochromes P450 restricted to furanocoumarins as substrates and the orphan CYP71AJ.

CONCLUSION

Two subclades functionally assigned to the biosynthesis of furanocoumarins and four other subclades were identified and shown to be part of two distinct clades within the CYP71AJ subfamily. The subclades show significant variability within their substrate recognition sites between the clades, suggesting different biochemical functions and providing insights into the evolution of cytochrome P450 'blooms' in response to environmental pressures.

Thapsigargin--from Thapsia L. to mipsagargin

The sesquiterpene lactone thapsigargin is found in the plant Thapsia garganica L., and is one of the major constituents of the roots and fruits of this Mediterranean species. In 1978, the first pharmacological effects of thapsigargin were established and the full structure was elucidated in 1985. Shortly after, the overall mechanism of the Sarco-endoplasmic reticulum Ca²⁺-ATPase (SERCA) inhibition that leads to apoptosis was discovered. Thapsigargin has a potent antagonistic effect on the SERCA and is widely used to study Ca²⁺-signaling. The effect on SERCA has also been utilized in the treatment of solid tumors. A prodrug has been designed to target the blood vessels of cancer cells; the death of these blood vessels then leads to tumor necrosis. The first clinical trials of this drug were initiated in 2008, and the potent drug is expected to enter the market in the near future under the generic name Mipsagargin (G-202). This review will describe the discovery of the new drug, the on-going elucidation of the biosynthesis of thapsigargin in the plant and attempts to supply the global market with a novel potent anti-cancer drug.

Metabolic engineering of the moss Physcomitrella patens to produce the sesquiterpenoids patchoulol and α/β-santalene

The moss Physcomitrella patens, has been genetically engineered to produce patchoulol and β-santalene, two valuable sesquiterpenoid ingredients in the fragrance industry. The highest yield of patchoulol achieved was 1.34 mg/g dry weight. This was achieved by non-targeted transformation of the patchoulol synthase and either a yeast or P. patens HMGR gene under the control of a 35S promoter. Santalene synthase targeted to the plastids yielded 0.039 mg/g dry weight of α/β santalene; cytosolic santalene synthase and 35S controlled HMGR afforded 0.022 mg/g dry weight. It has been observed that the final yield of the fragrance molecules is dependent on the expression of the synthase. This is the first report of heterologous production of sesquiterpenes in moss and it opens up a promising source for light-driven production of valuable fragrance ingredients.

High-throughput testing of terpenoid biosynthesis candidate genes using transient expression in Nicotiana benthamiana

To respond to the rapidly growing number of genes putatively involved in terpenoid metabolism, a robust high-throughput platform for functional testing is needed. An in planta expression system offers several advantages such as the capacity to produce correctly folded and active enzymes localized to the native compartments, unlike microbial or prokaryotic expression systems. Two inherent drawbacks of plant-based expression systems, time-consuming generation of transgenic plant lines and challenging gene-stacking, can be circumvented by transient expression in Nicotiana benthamiana. In this chapter we describe an expression platform for rapid testing of candidate terpenoid biosynthetic genes based on Agrobacterium mediated gene expression in N. benthamiana leaves. Simultaneous expression of multiple genes is facilitated by co-infiltration of leaves with several engineered Agrobacterium strains, possibly making this the fastest and most convenient system for the assembly of plant terpenoid biosynthetic routes. Tools for cloning of expression plasmids, N. benthamiana culturing, Agrobacterium preparation, leaf infiltration, metabolite extraction, and automated GC-MS data mining are provided. With all steps optimized for high throughput, this in planta expression platform is particularly suited for testing large panels of candidate genes in all possible permutations.

Heterologous stable expression of terpenoid biosynthetic genes using the moss Physcomitrella patens

Heterologous and stable expression of genes encoding terpenoid biosynthetic enzymes in planta is an important tool for functional characterization and is an attractive alternative to expression in microbial hosts for biotechnological production. Despite improvements to the procedure, such as streamlining of large scale Agrobacterium infiltration and upregulation of the upstream pathways, transient in planta heterologous expression quickly reaches limitations when used for production of terpenoids. Stable integration of transgenes into the nuclear genome of the moss Physcomitrella patens has already been widely recognized as a viable alternative for industrial-scale production of biopharmaceuticals. For expression of terpenoid biosynthetic genes, and reconstruction of heterologous pathways, Physcomitrella has unique attributes that makes it a very promising biotechnological host. These features include a high native tolerance to terpenoids, a simple endogenous terpenoid profile, convenient genome editing using homologous recombination, and cultivation techniques that allow up-scaling from single cells in microtiter plates to industrial photo-bioreactors. Beyond its use for functional characterization of terpenoid biosynthetic genes, engineered Physcomitrella can be a green biotechnological platform for production of terpenoids. Here, we describe two complementary and simple procedures for stable nuclear transformation of Physcomitrella with terpenoid biosynthetic genes, selection and cultivation of transgenic lines, and metabolite analysis of terpenoids produced in transgenic moss lines. We also provide tools for metabolic engineering through genome editing using homologous recombination.

Tea toxicity and cholinesterase inhibition of Huilliche herbal medicine

Eleven species of Huilliche medicinal plants used traditionally against infections and for wound healing were tested for their cholinesterase inhibition activity. Two different teas (a 5-7 min infusion and a 1 h decoction, both in water) were tested for their toxicity against Artemia salina. The results from the present study clearly show that teas boiled for 1 h is much more toxic than teas infused for 5-7 min. These results support the different traditional use of the two teas, where the 1h tea is for external use only. Additionally, significant inhibition of cholinesterase has been observed for MeOH extracts of Acaena argentea, Amomyrtas meli and Pseudopanax laetevirens, with that of A. argentea being the most potent. All findings call for further investigations.

A comparison of headspace solid-phase microextraction and classic hydrodistillation for the identification of volatile constituents from Thapsia spp. provides insights into guaianolide biosynthesis in Apiaceae

INTRODUCTION

Thapsia spp. (Apiaceae) are the major natural source of polyoxygenated guaianolide sesquiterpene lactones known as thapsigargins, which induce apoptosis in mammalian cells via a high affinity inhibition of the sarco/endoplasmic reticulum Ca(2+) ATPase. The mechanism of biosynthesis of thapsigargins has not been elucidated, and probable biochemical precursors such as hydrocarbon or oxygenated sesquiterpenes have not been identified in previous phytochemical analyses of essential oils from this genus.

OBJECTIVE

To investigate the utility of solid phase micro-extraction (SPME), when compared with classical essential oil distillates, for identifying potential precursors of guaianolide sesquiterpene lactones from Thapsia garganica L. and Thapsia villosa L. type II.

METHODOLOGY

A systematic description of the volatile components of roots, flowers, stems and fruits of T. villosa and of root, flower and fruits of T. garganica was constructed via GC-MS analyses of SPME-adsorbed compounds and of essential oils obtained through hydrodistillation of the same tissues.

RESULTS

The sesquiterpenoids δ-cadinene, α- and δ-guaiene, elemol and guaiols were found to be major volatile constituents of the roots of T. garganica and T. villosa trapped using SPME. In contrast, these sesquiterpenoids were not detected or were at negligible levels in essential oils, where sesquiterpenoids are potentially converted to azulenes during hydrodistillation.

CONCLUSION

The new data reported in this study demonstrates that SPME is a valuable tool for the identification of volatile sesquiterpenes when compared with analysis of essential oils, and we postulate that guaiene is the likely precursor of guaianolide sesquiterpenes from Thapsia.

Antimicrobial evaluation of Huilliche plant medicine used to treat wounds

ETHNOPHARMACOLOGICAL RELEVANCE

The traditional use of 40 plant species used for treatment of wounds and associated infections by the Huilliche people of Chile was evaluated against bacterial and fungal human pathogens, especially including wound pathogens.

MATERIALS AND METHODS

The extracts were tested against the fungi Penicillium expansum, Candida albicans and the bacteria Bacillus subtilis, Pseudomonas aeruginosa (four different strains), Staphylococcus aureus, Escherichia coli (four different strains), Streptococcus pneumoniae (four different strains with one being resistance to streptomycin).

RESULTS

Thirteen of the plant species have interesting antimicrobial activities, with that of Acaena argentea, Aristotelia chilensis, Blechnum chilense, Francoa appendiculta, Gevuina avellana and Laureliopsis philippiana being the most noteworthy.

CONCLUSIONS

The findings in the manuscript support the traditional use by the Huilliche people, and allow enhanced economical benefit and use by the locals. The results obtained on Acaena argentea, Aristotelia chilensis, Blechnum chilense, Francoa appendiculta, Gevuina avellana and Laureliopsis philippiana are of specific scientific interest, and further studies is needed in order to establish the active constituents of the species.

Mapuche herbal medicine inhibits blood platelet aggregation

12 plant species traditionally used by the Mapuche people in Chile to treat wounds and inflammations have been evaluated for their direct blood platelet inhibition. Seven of the 12 tested plant species showed platelet inhibitory effect in sheep blood, and four of these were also able to inhibit the ADP- (5.0 μM) and collagen- (2.0 μg/mL) induced aggregations in human blood. These four species in respective extracts (in brackets) were Blechnum chilense (MeOH), Luma apiculata (H(2)O), Amomyrtus luma (DCM : MeOH 1 : 1) and Cestrum parqui (DCM : MeOH 1 : 1). The platelet aggregating inhibitory effects of A. luma (DCM : MeOH 1 : 1), and L. apiculata (H(2)O) were substantial and confirmed by inhibition of platelet surface activation markers.

Effect of Antioxidants and Carbohydrates in Callus Cultures of Taxus brevifolia: Evaluation of Browning, Callus Growth, Total Phenolics and Paclitaxel Production

INTRODUCTION

To control the tissue browning phenomenon, callus growth, total phenolics and paclitaxel production, in the current investigation, we evaluated the effects of citric acid and ascorbic acid (as antioxidants) and glucose, fructose and sucrose in callus cultures of Taxus brevifolia.

METHODS

To obtain healthy callus/cell lines of Taxus brevifolia, the effects of two antioxidants ascorbic acid (100-1000 mg/L) and citric acid (50-500 mg/L), and three carbohydrates (glucose, fructose and sucrose (5-10 g/L)) were studied evaluating activities of polyphenol oxidase (PPO) and peroxidase (PO) enzymes, callus growth/browning, total phenolics and paclitaxel production.

RESULTS

These antioxidants (ascorbic acid and citric acid) failed to show significant effects on callus growth, browning intensity or paclitaxel production. However, the carbohydrates imposed significant effects on the parameters studied. High concentrations of both glucose and sucrose increased the browning intensity, thus decreased callus growth. Glucose increased paclitaxel production, but sucrose decreased it.

CONCLUSION

These results revealed that the browning phenomenon can be controlled through supplementation of the growth media with glucose, sucrose (5 g/L) and fructose (10 g/L), while increased paclitaxel production can be obtain by the optimized media supplemented with glucose (10 g/L), sucrose and fructose (5 g/L).

Article Commentary: Capsaicin—the Hot and Spicy Diet Turned Mild and Effective by Glycosylation

Shimoda and coworkers 1 published a paper on the pharmacological properties of glycosides of the peppery compound capsaicin (1) and its derivative 8-nordihydrocapsaicin (2). In their paper they conclude that the β-glucoside and β-maltoside of 1 and the β-glucoside of 2 still have the same potent anti-obese activity but further studies are needed to determine the physiological effect. Shimoda et al. 1 use glycosylation to make a drug candidate more water soluble to promote their research for new drug candidates within the chemical group of capsaicinoids. Their findings support that this is a plausible way to enhance both bioavailability and “drug-likeliness” properties of drug candidates. This is indeed an interesting approach which should be pursued further and by many more.

Molecular interactions between barley and oat beta-glucans and phenolic derivatives

Equilibrium dialysis, molecular modeling, and multivariate data analysis were used to investigate the nature of the molecular interactions between 21 vanillin-inspired phenolic derivatives, 4 bile salts, and 2 commercially available beta-glucan preparations, Glucagel and PromOat, from barley and oats. The two beta-glucan products showed very similar binding properties. It was demonstrated that the two beta-glucan products are able to absorb most phenolic derivatives at a level corresponding to the absorption of bile salts. Glucosides of the phenolic compounds showed poor or no absorption. The four phenolic derivatives that showed strongest retention in the dialysis assay shared the presence of a hydroxyl group in para-position to a CHO group. However, other compounds with the same structural feature but possessing a different set of additional functional groups showed less retention. Principal component analysis (PCA) and partial least-squares regression (PLS) calculations using a multitude of diverse descriptors related to electronic, geometrical, constitutional, hybrid, and topological features of the phenolic compounds showed a marked distinction between aglycon, glucosides, and bile salt retention. These analyses did not offer additional information with respect to the mode of interaction of the individual phenolics with the beta-glucans. When the barley beta-glucan was subjected to enzyme degradation, the ability to bind some but not all of the phenolic derivatives was lost. It is concluded that the binding must be dependent on multiple characteristics that are not captured by a single molecular descriptor.

Perspectives on using physcomitrella patens as an alternative production platform for thapsigargin and other terpenoid drug candidates

To overcome the potential future demand for terpenoids used as drugs, a new production platform is currently being established in our laboratory. The moss Physcomitrella has been chosen as the candidate organism for production of drug candidates based on terpenoids derived from plants, with a primary focus on the sesquiterpene lactone, thapsigargin. This drug candidate and other candidates/drugs with sesquiterpene skeleton are difficult to obtain by chemical synthesis due to their large number of chiral centers. Furthermore, they are not available in sufficient amounts from their original plant. The requirement for a new production system to meet the potential market demand for these compounds is not only obvious, but also essential if sufficient quantities of the drug candidates are to be available for the potential therapeutic use.

Sulfur starvation in rice: the effect on photosynthesis, carbohydrate metabolism, and oxidative stress protective pathways

Sulfur-deficient plants generate a lower yield and have a reduced nutritional value. The process of sulfur acquisition and assimilation play an integral role in plant metabolism, and response to sulfur deficiency involves a large number of plant constituents. Rice (Oryza sativa) is the second most consumed cereal grain, and the effects of sulfur deprivation in rice were analyzed by measuring changes in photosynthesis, carbohydrate metabolism, and antioxidants. The photosynthetic apparatus was severely affected under sulfur deficiency. The Chl content was reduced by 49% because of a general reduction of PSII and PSI and the associated light-harvesting antenna. The PSII efficiency was 31% lower at growth light, and the ability of PSI to photoreduce NADP+ was decreased by 61%. The Rubisco content was also significantly reduced in the sulfur-deprived plants. The imbalances between PSII and PSI, and between photosynthesis and carbon fixation led to a general over-reduction of the photosynthetic electron carriers (higher 1-q(P)). Chromatographic analysis showed that the level of monosaccharides was lower and starch content higher in the sulfur-deprived plants. In contrast, no changes in metabolite levels were found in the tricarboxylic acid or Calvin cycle. The level of the thiol-containing antioxidant, GSH, was 70% lower and the redox state was significantly more oxidized. These changes in GSH status led to an upregulation of the cytosolic isoforms of GSH reductase and monodehydroascorbate reductase. In addition, alternative antioxidants like flavonoids and anthocyanins were increased in the sulfur-deprived plants.

Disruption of the copper efflux pump (CopA) of Serratia marcescens ATCC 274 pleiotropically affects copper sensitivity and production of the tripyrrole secondary metabolite, prodigiosin

The prodigiosin biosynthetic gene cluster (pig cluster) of Serratia marcescens ATCC 274 (Sma 274) is flanked by cueR/copA homologues. Inactivation of the copA homologue resulted in an increased sensitivity to copper, confirming that CopA is involved in copper homeostasis in Sma 274. The effect of copper on the biosynthesis of prodigiosin in Sma 274 and the copA mutant strain was investigated. Increased levels of copper were found to reduce prodigiosin production in the wild type Sma 274, but increase production in the copA mutant strain. The physiological implications for CopA mediated prodigiosin production are discussed. We also demonstrate that the gene products of pigB-pigE of Sma 274 are sufficient for the biosynthesis of 2-methyl-3-n-amyl-pyrrole and condensation with 4-methoxy-2,2'-bipyrrole-5-carboxyaldehyde to form prodigiosin, as we have shown for Serratia sp. ATCC 39006.

Antifungal constituents ofMelicope borbonica

Fractionation of extracts of the leaves of Melicope borbonica (syn. Euodia borbonica var. borbonica), a medicinal plant from the Réunion Island that is traditionally used for wound healing and other ailments, afforded an acetophenone (xanthoxylin) and two coumarins, scoparone and limettin, as the major constituents. All three compounds exhibited moderate antifungal activity against Candida albicans and Penicillium expansum, in accordance with the traditional use of the plant. Moreover, 2,4,6-trimethoxyacetophenone (methylxanthoxylin), three other coumarins [7-(3-methyl-2-butenyloxy)-6-methoxycoumarin, cedrelopsin and psoralen], two sesquiterpenes (alpha-curcumene and 3,6-epidioxy-1,10-bisaboladiene), eugenol, methyleugenol and a lignan (sesamin) were isolated. None of the isolated constituents exhibited antiin fl ammatory activity in vitro. No alkaloids were detected.

In vitro screening of Indian medicinal plants for antiplasmodial activity

Plants traditionally used in India to treat fever or malaria were examined in vitro for antiplasmodial properties against Plasmodium falciparum. Of 80 analysed ethanol extracts, from 47 species, significant effects were found for 31 of the extracts. These represent 23 different species from 20 families. Of the active species 20 were tested against P. falciparum for the first time. The following five species seems to be of special interest for further antimalarial studies, Casearia elliptica, Holarrhena pubescens, Pongamia pinnata, Soymida febrifuga, and Plumbago zeylanica.