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Background: Phalaenopsis bellina, an orchid native to Borneo, is renowned for its unique appearance. It releases distinct fragrances, which have been linked to the presence of terpenoids. However, the identification and study of sesquiterpene synthase in P. bellina remain limited. In this study, we examines the functional characterisation of terpene synthase (TPS) from P. bellina, known as PbTS, through recombinant protein expression and its manifestation in the flower. Methods and Results: Gene annotation of PbTS revealed that the inferred peptide sequence of PbTS comprises 1,680 bp nucleotides encoding 559 amino acids with an estimated molecular mass of 65.2 kDa and a pI value of 5.4. A similarity search against GenBank showed that PbTS shares similarities with the previously published partial sequence of P. bellina (ABW98504.1) and Phalaenopsis equestris (XP_020597359.1 and ABW98503.1). Intriguingly, the phylogenetic analysis places the PbTS gene within the TPS-a group. In silico analysis of PbTS demonstrated stable interactions with farnesyl pyrophosphate (FPP), geranyl pyrophosphate (GPP), and geranylgeranyl pyrophosphate (GGPP). To verify this activity, an in vitro enzyme assay was performed on the PbTS recombinant protein, which successfully converted FPP, GPP, and GGPP into acyclic sesquiterpene β-farnesene, yielding approximately 0.03 mg/L. Expressional analysis revealed that the PbTS transcript was highly expressed in P. bellina, but its level did not correlate with β-farnesene levels across various flowering time points and stages. Conclusion: The insights gained from this study will enhance the understanding of terpenoid production in P. bellina and aid in the discovery of novel fragrance-related genes in other orchid species. [ABSTRACT FROM AUTHOR]

Lycopene is a compound classified as carotenoid, also known as tetraterpenoids, and its high antioxidative capabilities make demand in pharmaceutical and nutrient fields. For these reasons, much research on microbial production of lycopene has been developed and reported for more than two decades. Nevertheless, a standardized in vitro biosynthesis method for lycopene synthesis has not been reported to date. The major reasons of the absence of this method lie on the poor solubility of hydrophobic intermediates (geranylgeranyl pyrophosphate [GGPP] and phytoene), and the difficulty of employing membrane-binding enzyme, phytoene desaturase (CrtI) into in vitro reactions. In this study, we developed a standard method of in vitro biosynthesis of lycopene from geranyl pyrophosphate using four enzymes, namely farnesyl pyrophosphate synthase (IspA), GGPP synthase (CrtE), phytoene synthase (CrtB), phytoene desaturase (CrtI), and liposome-the key material, which can provide both hydrophobic area and a lipid membrane for the membrane-binding enzyme CrtI. Moreover, we performed a screening of the in vitro lycopene synthetic pathway using cell-free protein synthesis system, which verifies the applicability of our system as a tool for screening the lycopene synthesis pathway. [ABSTRACT FROM AUTHOR]

Numerous herbal products have been the subject of research regarding their potential role in cancer prevention or adjuvant therapy. Pistacia atlantica and its main phytochemicals have garnered significant attention for their potential anti-cancer effects. The study aimed to assess the growth inhibitory effects of P. atlantica essential oil (PAEO) on MKN-45 and AGS cells. This study quantified the volatile compounds in PAEO using Gas Chromatography–Mass Spectrometry (GC–MS). Subsequently, MKN-45 and AGS cells were treated with varying concentrations of PAEO (5%, 2.5%, 1.25%, 0.625%, 0.3125%, 0.156%, 0.0781%, 0.0391%, 0.0195%) for 24 h. Cell viability was evaluated through the MTT assay. The impact of PAEO on gene expression was investigated by quantifying the mRNA levels of Bax and Bcl2 in the various experimental groups using quantitative Real-Time PCR (qRT-PCR) analysis. Additionally, flow cytometry was utilized to evaluate apoptosis in the treated cells. The analysis of PAEO revealed that α-pinene was the predominant monoterpene, constituting 87.9% of the oil composition. The cytotoxic effects of PAEO were evaluated, and it was found that the oil significantly reduced the viability of MKN-45 and AGS cells. The IC50 for MKN-45 cells was determined to be 1.94 × 10–3% after 24 h of treatment, while for AGS cells the IC50 was 2.8 × 10–3% after 24 h. Additionally, the research revealed that PAEO triggered a notable rise in apoptotic cells in both AGS and MKN-45 cell lines. Moreover, at the molecular level, the findings indicated an increase in Bax expression and a decrease in Bcl2 mRNA expression, providing further evidence of the induction of apoptosis in both MKN-45 and AGS cell lines following PAEO treatment. The findings of this study offer evidence supporting the cytotoxic effects of PAEO on gastric cancer cell lines by promoting apoptosis. The findings suggest that PAEO may offer potential as a therapeutic candidate in managing and treating gastric cancer. [ABSTRACT FROM AUTHOR]

Protein modeling, carbocation docking, and molecular dynamics along with structure-based mutability landscapes provided insight into taxadiene synthase catalysis (first step of the anticancer Taxol biosynthesis), protein structure-function correlations, and promiscuity. Plant terpenes belong to one of the largest and most diverse classes of natural products. This diversity is driven by the terpene synthase enzyme family which comprises numerous different synthases, several of which are promiscuous. Taxadiene synthase (TXS) is a class I diterpene synthase that catalyzes the first step in the biosynthesis pathway of the diterpene Taxol, an anticancer natural product produced by the Taxus plant. Exploring the molecular basis of TXS catalysis and its promiscuous potential garnered interest as a necessary means for understanding enzyme evolution and engineering possibilities to improve Taxol biosynthesis. A catalytically active closed conformation TXS model was designed using the artificial intelligence system, AlphaFold, accompanied by docking and molecular dynamics simulations. In addition, a mutability landscape of TXS including 14 residues was created to probe for structure-function relations. The mutability landscape revealed no mutants with improved catalytic activity compared to wild-type TXS. However, mutations of residues V584, Q609, V610, and Y688 showed high degree of promiscuity producing cembranoid-type and/or verticillene-type major products instead of taxanes. Mechanistic insights into V610F, V584M, Q609A, and Y688C mutants compared to the wild type revealed the trigger(s) for product profile change. Several mutants spanning residues V584, Q609, Y688, Y762, Q770, and F834 increased production of taxa-4(20),11(12)-diene which is a more favorable substrate for Taxol production compared to taxa-4(5),11(12)-diene. Finally, molecular dynamics simulations of the TXS reaction cascade revealed residues involved in ionization, carbocation stabilization, and cyclization ushering deeper understanding of the enzyme catalysis mechanism. [ABSTRACT FROM AUTHOR]

Terpenoids are widely used in the food, beverage, cosmetics, and pharmaceutical industries. Microorganisms have been extensively studied for terpenoid production. In yeast, the introduction of the mevalonate (MVA) pathway in organelles in addition to the augmentation of its own MVA pathway have been challenging. Introduction of the MVA pathway into mitochondria is considered a promising approach for terpenoid production because acetyl-CoA, the starting molecule of the MVA pathway, is abundant in mitochondria. However, mitochondria comprise only a small percentage of the entire cell. Therefore, we hypothesized that increasing the total mitochondrial volume per cell would increase terpenoid production. First, we ascertained that the amounts of isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP), the final molecules of the MVA pathway, were 15-fold higher of the strain expressing the MVA pathway in mitochondria than in the wild-type yeast strain. Second, we found that different deletion mutants induced different mitochondrial volumes by measuring the mitochondrial volume in various deletion mutants affecting mitochondrial morphology; for example,Δmdm32 increased mitochondrial volume, and Δfzo1 decreased it. Finally, the effects of mitochondrial volume on amounts of IPP/DMAPP and terpenoids (squalene or β-carotene) were investigated using mutants harboring large or small mitochondria expressing the MVA pathway in mitochondria. Amounts of IPP/DMAPP and terpenoids (squalene or β-carotene) increased when the mitochondrial volume expanded. Introducing the MVA pathway into mitochondria for terpenoid production in yeast may become more attractive by enlarging the mitochondrial volume. Key points: • IPP/DMAPP content increased in the strain expressing the MVA pathway in mitochondria • IPP/DMAPP and terpenoid contents are positively correlated with mitochondrial volume • Enlarging the mitochondria may improve mitochondria-mediated terpenoid production [ABSTRACT FROM AUTHOR]

Plant secondary metabolites can protect organisms against oxidative stress caused by adverse environmental conditions. Cinnamomum camphora (L.) J. Presl contains plentiful terpenoids and is subdivided into 5 chemotypes. To develop natural antioxidants using the plant terpenoids, the terpenoid composition and antioxidant abilities of methanol, ethyl acetate, n-hexane and petroleum ether extracts from linalool and eucalyptol chemotypes were investigated, and the solvent effects on in vitro antioxidant activity of 8 main terpenoids were analyzed. Meanwhile, the in vivo effects of two strong antioxidant terpenoids were evaluated. For the two chemotypes, the 4 solvents exhibited the same extracting effects on the terpenoid types, but methanol extracts contained the highest content of terpenoids, which should contribute to their strongest scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radicals. In linalool and eucalyptol chemotype extracts, linalool, eucalyptol, ocimene, α-pinene, D-limonene, terpinene, β-pinene and longifolene were the 8 main terpenoids. Among the 4 solvents, the 8 terpenoids showed the strongest free radical-scavenging activity with methanol as the reaction medium, which might result from strong-polarity methanol easily activating C = C unsaturated bonds in these compounds. This might also contribute to the strongest scavenging activity of methanol extracts against free radicals. Among these main components, ocimene and longifolene separately showed the strongest activity in scavenging DPPH and ABTS free radical. In in vivo assay, the two compounds significantly lowered the reactive oxygen species (ROS) levels in Chlamydomonas reinhardtii, a single-celled model organism, under H2O2 stress, and the lowering effects gradually enhanced with increasing the compound concentration, resulting in the corresponding promoting effect on the algal growth. At the same concentration, longifolene showed the strongest effect on protecting the algal cells against oxidative stress. Therefore, methanol was suitable for extracting terpenoids in natural antioxidant development, and ocimene and longifolene were two strong antioxidant terpenoids without cell toxicity, with the latter having stronger in vivo antioxidant activity. [ABSTRACT FROM AUTHOR]

Key message: This review summarized how TFs function independently or in response to environmental factors to regulate terpenoid biosynthesis via fine-tuning the expression of rate-limiting enzymes. Terpenoids are derived from various species and sources. They are essential for interacting with the environment and defense mechanisms, such as antimicrobial, antifungal, antiviral, and antiparasitic properties. Almost all terpenoids have high medicinal value and economic performance. Recently, the control of enzyme genes on terpenoid biosynthesis has received a great deal of attention, but transcriptional factors regulatory network on terpenoid biosynthesis and accumulation has yet to get a thorough review. Transcription factors function as activators or suppressors independently or in response to environmental stimuli, fine-tuning terpenoid accumulation through regulating rate-limiting enzyme expression. This study investigates the advancements in transcription factors related to terpenoid biosynthesis and systematically summarizes previous works on the specific mechanisms of transcription factors that regulate terpenoid biosynthesis via hormone signal–transcription regulatory networks in plants. This will help us to better comprehend the regulatory network of terpenoid biosynthesis and build the groundwork for terpenoid development and effective utilization. [ABSTRACT FROM AUTHOR]

Coconut haustorium (CH) is formed inside coconut shell during coconut germination. This study aimed to investigate the compositions and contents of CH phytochemicals. Phytochemical compositions and contents in CH were analyzed by ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) and spectrophotometrical method. Five phenolic acids and four flavonoids were identified in CH. Ferulic acid and myricetin were the most abundant among phenolic acids and flavonoids identified in CH, respectively. Nepetariaside and 1-methylene-5α-androstan-3α-ol-17-one glucuronide were the most abundant terpenoids and steroid derivatives identified in CH, respectively. To our knowledge, this study screened several classes of phytochemicals in CH for the first. Terpenoids and steroid derivatives were likely to be more major phytochemicals than phenolic acids and flavonoids in CH. The functionality of CH itself and the compounds found in CH might be utilized in functional foods or cosmetics. [ABSTRACT FROM AUTHOR]

Chrysanthemum indicum var. aromaticum (C. indicum var. aromaticum) is an important aromatic plant resource in the Chrysanthemum genus, and the main substance of its aroma is terpenoids. Myelocytomatosis 2 (MYC2) is essential for the JA response to the accumulation of secondary metabolites in several plants. However, there are few reports on the regulation of terpenoid secondary metabolism and the improvement of aromatic characters by Chrysanthemum MYC2 transcription factor. In this study, a C. indicum var. aromaticum MYC2 transcription factor, CiMYC2, was induced by methyl jasmonate and preferentially expressed in leaves. The overexpression of CiMYC2 in tobacco resulted in shorter plant height, darker leaf color, higher chlorophyll and carotenoid content, more long-handle trichomes and short-handle trichomes, and higher terpenes content compared with wild-type (WT) and empty vector (EV) lines. More importantly, some novel terpenes were detected in CiMYC2 transgenic tobacco lines, whereas no corresponding substances were detected in WT and EV lines. In addition, transcriptional analyses revealed that the expression levels of genes involved in the terpenoids biosynthesis pathways were higher in transgenic tobacco lines than those in the WT and EV lines. Results indicated that CiMYC2 may be a key regulator for terpenoids biosynthesis in C. indicum var. aromaticum plants. The research results will provide theoretical basis for creating high terpene aromatic materials and cultivating new varieties of aromatic chrysanthemum using transgenic engineering technology. [ABSTRACT FROM AUTHOR]

Plant microRNAs (miRNAs) are short, non-coding RNA molecules. They mediate RNA silencing and regulate a series of target mRNAs involved in plant development, metabolism, and responses to different ecological environments. As one of important medicinal plants, Atractylodes lancea has a high medicinal significance and commercial value. Mao and Dabie are two ecotypes of A. lancea which mainly distributes in Mao Mountain and Dabie Mountain, respectively. To better understand the genomic information and germplasm resource characteristics, miRNA profiling analysis by high-throughput sequencing was performed to identify rhizome miRNAs of two A. lancea ecotypes. A transcriptomic database was established to identify miRNAs precursors and their target transcripts. By comparing small RNAs and the transcriptomic database, 270 known miRNAs of 46 miRNA families and 91 novel miRNAs were identified, plus hundreds of putative targets. Using Mireap software, 5 and 12 of 22 significant differentially expressed miRNAs were involved in ecotype formation and terpenoid metabolism, respectively, which was verified by qRT-PCR tests. These results are an important resource to better understand the biological mechanism of terpene formation and A. lancea adaptation to different ecological environment. [ABSTRACT FROM AUTHOR]

Terpenoids are natural compounds originating from five-carbon isoprene units. Over 60,000 terpenoid structures have been identified, and they contribute to the flavor, color, growth, and development of plants. There are several reports on various physiological activities of terpenoids, such as antioxidative and anticancer activities. This study revealed that combinations of terpenoids have activities against a spectrum of bacteria. The combination of carvacrol and thymol has bacteriostatic and bactericidal activities. Four terpenoids (carvacrol, thymol, eugenol, and nootkatone) exhibited bacteriostatic and bactericidal activities when used at low concentrations for 5‒10 min. The most effective bactericidal activity was observed for gram-negative bacteria. A very weak bactericidal activity was observed against Staphylococcus aureus and Enterococcus faecalis. This study revealed the antibacterial potential of different combinations of terpenoids against several bacteria that were tested. Thus, new candidates for the development of antibacterial medicines are reported here for the effective treatment of infectious bacterial diseases. [ABSTRACT FROM AUTHOR]

In this work, we report the synthesis and antitubercular activity of sixteen fluoroquinolones analogs of Cipro-, Gati-, Moxi-, and Gemifloxacin coupled with the terpenes, prenol, geraniol, nerol or farnesol, being all new compounds. The reactions were carried in a microwave reactor with short reaction times of 3–10 min, providing compounds in moderated yields. Fourteen of sixteen assessed fluoroquinolone derivatives were active against the M. tuberculosis, being the best result observed to a compound two times more active than the starting fluoroquinolone Gemifloxacin. These results confirm the potential of fluoroquinolone derivatives as lead compounds in antimycobacterial drug discovery. [ABSTRACT FROM AUTHOR]

Bioactive terpenoids 1 and 2 along with a known compound, β-sitosterol, have been isolated from the DCM extract of the fruits of Lagerstroemia speciosa. Structures of 1 and 2 have been established by spectroscopic analysis. In vitro antibacterial and antifungal activity of 1 and 2 have been reported. Compound 1 showed poor activity, but compound 2 exhibited significant antibacterial and antifungal activities. Molecular docking study of 2 also showed a good docking score within the binding pocket of the selected proteins. [ABSTRACT FROM AUTHOR]

Cannabis spp. are some of the most controversial medicinal plants in the world. They contain great amounts of biologically active secondary metabolites, including the typical phenolic compounds called cannabinoids. Because of their low toxicity and complex biological activities, cannabinoids can be useful in the therapy of various diseases, but adverse psychological effects (of Δ9-THC in particular) raise concerns. This review summarizes the current knowledge of selected active C. indica compounds and their therapeutic potential. We summarize the main compounds contained in cannabis, the mechanisms of their effects, and their potential therapeutic applications. Further, we mention some of the clinical tests used to evaluate the efficacy of cannabinoids in therapy. [ABSTRACT FROM AUTHOR]

Terpenoids are natural compounds predominantly present in plants. They have many pharmaceutical and/or nutritional functions, and have been widely applied in medical, food, and cosmetics industries. Recently, terpenoids have been used in the clinical treatment of COVID-19 due to the good antiviral activities. The increasing demand for terpenoids in international markets poses a serious threat to many plant species. For environmentally sustainable development, microbial cell factories have been utilized as the promising platform to produce terpenoids. Nevertheless, the bioproduction of most terpenoids cannot meet commercial requirements due to the low cost-benefit ratio until now. The biosynthetic potential of endophytes has gained attention in recent decades owing to the continual discovery of endophytes capable of synthesizing plant bioactive compounds. Accordingly, endophytes could be alternative sources of terpenoid-producing strains or terpenoid synthetic genes. In this review, we summarized the research progress describing the main and supporting roles of endophytes in terpenoid biosynthesis and biotransformation, and discussed the current problems and challenges which may prevent the further exploitation. This review will improve our understanding of endophyte resources for terpenoid production in industry in the future. Key points • The mechanisms employed by endophytes in terpenoid synthesis in vivo and in vitro. • Endophytes have the commercial potentials in terpenoid bioproduction and biotransformation. • Synthetic biology and multiomics will improve terpenoid bioproduction in engineered cell factories. [ABSTRACT FROM AUTHOR]

Terpene synthase (TPS) gene family is ubiquitous in land plants and plays an important role in regulating various biological processes in plants, especially in pathogen and herbivore defense mechanisms. Also, little is known about this gene family in wheat. In this research, 153 TaTPS genes were identified and named according to their chromosome location. Phylogenetic analysis of TaTPS proteins and other homologous proteins corresponded to a six-subgroup classification. The analysis of gene structure and motif showed that the TaTPS gene was highly conserved in each subgroup, which suggested that whole genome duplication and segmental duplication events were the main expansion way of the TaTPS gene family. Nineteen tandem duplication gene pairs and 91 homologous genes on different chromosomes were produced by segmental duplication. Expression profiles derived from transcriptome data results indicated that TaTPS genes may contribute to defense responses of wheat to pests such as aphids. The cis-regulatory elements (CREs) of TaTPS were found to be diversified indicating that TaTPS gene may participate in many physiological processes of wheat growth and development. Each TaTPS gene contains at least two or more defense or hormone-related CREs, suggesting an important role in wheat pest defense through hormone pathways. This study can provide valuable clues for elucidating the evolutionary relationship of the TaTPS gene family. Also, it may provide a research basis for functional investigations related to wheat development, particularly to plant–pest interactions and further breeding for new wheat varieties with aphid resistance. [ABSTRACT FROM AUTHOR]

Melleolides and armillyl orsellinates are protoilludene-type aryl esters that are synthesized exclusively by parasitic fungi of the globally distributed genus Armillaria (Agaricomycetes, Physalacriaceae). Several of these compounds show potent antimicrobial and cytotoxic activities, making them promising leads for the development of new antibiotics or drugs for the treatment of cancer. We recently cloned and characterized the Armillaria gallica gene Pro1 encoding protoilludene synthase, a sesquiterpene cyclase catalyzing the pathway-committing step to all protoilludene-type aryl esters. Fungal enzymes representing secondary metabolic pathways are sometimes encoded by gene clusters, so we hypothesized that the missing steps in the pathway to melleolides and armillyl orsellinates might be identified by cloning the genes surrounding Pro1. Here we report the isolation of an A. gallica gene cluster encoding protoilludene synthase and four cytochrome P450 monooxygenases. Heterologous expression and functional analysis resulted in the identification of protoilludene-8α-hydroxylase, which catalyzes the first committed step in the armillyl orsellinate pathway. This confirms that ∆-6-protoilludene is a precursor for the synthesis of both melleolides and armillyl orsellinates, but the two pathways already branch at the level of the first oxygenation step. Our results provide insight into the synthesis of these valuable natural products and pave the way for their production by metabolic engineering. Key points: • Protoilludene-type aryl esters are bioactive metabolites produced by Armillaria spp. • The pathway-committing step to these compounds is catalyzed by protoilludene synthase. • We characterized CYP-type enzymes in the cluster and identified novel intermediates. [ABSTRACT FROM AUTHOR]

Gedunin is a natural tetranorterpenoid secondary metabolite found in plants of the Meliaceae family, which has been reported for its antiparasitic, antifungal and anticancer activities. Here, we describe the molecular mechanisms underlying the in vitro anti proliferative activity of gedunin (isolated from the mangrove plant Xylocarpus granatum) in human ovarian cancer cells. We observed that gedunin triggered severe ROS generation leading to DNA damage and cell cycle arrest in G2/M phase thus inhibiting cell proliferation. ROS upregulation also led to mitochondrial stress and membrane depolarization, which eventually resulted in mitochondria-mediated apoptosis following cytochrome C release, caspase 9, 3 activation, and PARP cleavage. Transmission electron microscopy of gedunin treated cells revealed sub-cellular features typical of apoptosis. Moreover, an upregulation in stress kinases like phospho-ERK 1/2, phospho-p38 and phospho-JNK was also observed in gedunin treated cells. Free radical scavenger N-Acetyl-L-Cysteine (NAC) reversed all these effects resulting in increased cell survival, abrogation of cell cycle arrest, rescue of mitochondrial membrane potential and suppression of apoptotic markers. Interestingly, gedunin is also an inhibitor of the evolutionarily conserved molecular chaperone Heat Shock Protein 90 (hsp90) responsible for maintaining cellular homeostasis. Targeting this chaperone could be an attractive strategy for developing cancer therapeutics since many oncogenic proteins are also client proteins of hsp90. Collectively, our findings provide insights into the molecular mechanism of action of gedunin, which may aid drug development efforts against ovarian cancer. [ABSTRACT FROM AUTHOR]

Recently, the research on conversion of biodiesel by-products to high value-added products has received much attention, due to the adverse effects of large accumulations of biodiesel by-products caused by the rapid increase in biodiesel production. Herein, this study investigated the utilization of by-products crude glycerol (CG-1 and CG-2) from two different industrial methods of biodiesel production and the favorable fermentation conditions for the high yield of β-farnesene by an engineered Escherichia coli F4, which harbored an optimized mevalonate pathway. Through analyzing by-products' components and fermentation performance, we found that CG-2 did not contain harmful impurities such as methanol and black solid impurities, and the β-farnesene production was up to 2.7 g/L from CG-2, which was similar to that from pure glycerol (2.5 g/L) and higher than that (2.21 g/L) from CG-1. Therefore, CG-2 was more suitable for β-farnesene production than CG-1, which might provide a reference for choosing a more suitable method on practical biodiesel production. Afterward, a variety of important fermentation conditions were explored using CG-2 as a substrate in shaken flasks. Under the optimal conditions (including induced cell density 1.0, initial cell density 0.25, temperature after induction 33 °C, initial medium pH 6.5), the yield of β-farnesene from CG-2 reached 10.31 g/L in a 5-L bioreactor, which was 2.8-fold higher than initial conditions in shake flasks and was the highest yield of β-farnesene produced from biodiesel by-products by fermentation as well. The recommended fermentation conditions in this work will provide a valuable reference for the industrial production of β-farnesene utilizing biodiesel by-products. [ABSTRACT FROM AUTHOR]

Main conclusion: Two terpene compounds and four genes were identified as potential biomarkers for further evaluation for Scots pine susceptibility or tolerance against Heterobasidion annosum. Scots pine (Pinus sylvestris) is one of the main sources of timber in the boreal zone of Eurasia. Commercial pine plantations are vulnerable to root and butt rot disease caused by the fungus Heterobasidion annosum. The pathogen affects host growth rate, causes higher mortality and decreases in timber quality, resulting in considerable economic losses to forest owners. Genetic and biochemical factors contributing to Scots pine tolerance against H. annosum infection are not well understood. We assessed the predictive values of a set of potential genetic and chemical markers in a field experiment. We determined the expression levels of 25 genes and the concentrations of 36 terpenoid compounds in needles of 16 Scots pine trees randomly selected from a natural population prior to artificial infection. Stems of the same trees were artificially inoculated with H. annosum, and the length of necrotic lesions was documented 5 months post inoculation. Higher expression level of four genes included in our analysis and encoding predicted α-pinene synthase (two genes), geranyl diphosphate synthase (GPPS), and metacaspase 5 (MC5), could be associated with trees exhibiting increased levels of necrotic lesion formation in response to fungal inoculation. In contrast, concentrations of two terpenoid compounds, β-caryophyllene and α-humulene, showed significant negative correlations with the lesion size. Further studies with larger sample size will help to elucidate new biomarkers or clarify the potential of the evaluated markers for use in Scots pine disease resistance breeding programs. [ABSTRACT FROM AUTHOR]

8-(3′,3′-Dimethylbutyl)-6-hydroxy-2,6,7,8-tetrahydropyrrolo[1,2-a]pyrimidin-3-one (1) and 5-isopentyl-4a,8a-dimethyldecahydronaphthalen-2-ol (2) have been isolated from the aerial part of Sida rhombifolia L. for the first time along with the previously reported stigmasterol. Their structures were established on the basis of spectral and chemical methods. [ABSTRACT FROM AUTHOR]

We report the identification of p-mentha-1,3-dien-8-ol, an unstable monoterpene alcohol, as a male-produced aggregation-sex pheromone component of the cerambycid beetle Paranoplium gracile (Leconte) (subfamily Cerambycinae, tribe Oemini), a species endemic to California. Headspace volatiles from live males contained a blend of nine cyclic terpenoids that were not detected in analogous samples from females. Volatiles produced by male Eudistenia costipennis Fall, also in the tribe Oemini, contained the same suite of nine compounds. Four compounds, dehydro-p-cymene, p-mentha-1,3-dien-8-ol, p,α,α-trimethylbenzyl alcohol, and an unidentified compound were found to elicit responses from antennae of P. gracile females in coupled gas chromatography-electroantennogram detection (GC-EAD) assays, whereas only p-mentha-1,3-dien-8-ol elicited responses from antennae of males. In field assays, p-mentha-1,3-dien-8-ol stabilized with the antioxidant butylated hydroxytoluene (BHT) attracted P. gracile of both sexes, indicating it functions as an aggregation-sex pheromone, as with other pheromones identified from its subfamily, the Cerambycinae. Adding four of the other compounds found in headspace samples to the dienol lure had no effect on attraction. Because of the instability of p-mentha-1,3-dien-8-ol, it seems likely that at least some of the compounds seen in the extracts of volatiles from both species are artefacts, rather than being components of the pheromone. [ABSTRACT FROM AUTHOR]

Urease is an important virulence factor for a variety of pathogenic bacteria strains such as Helicobacter pylori, which colonizes human gastric mucosa, and Proteus sp., responsible for urinary tract infections. Specific inhibition of urease activity could be a promising adjuvant strategy for eradication of these pathogens. Due to the interesting antiureolytic activity of carvone and the scant information regarding the inhibitory properties of corresponding monoterpenes, we decided to study selected monoterpenic ketones and their oxygen derivatives. Several monoterpenes and their terpenoid oxygen derivatives were evaluated in vitro against Sporosarcina pasteurii urease. The most effective inhibitors—derivatives of β-cyclocitral (ester 10 and bromolactone 14)—were described with Ki of 46.7 µM and 45.8 µM, respectively. Active inhibitors of native urease were tested against H. pylori and Proteus mirabilis whole cells. Here, the most active inhibitor, 14, was characterized with IC50 values of 0.32 mM and 0.61 mM for P. mirabilis and H. pylori, respectively. The antibacterial activity of a few tested inhibitors was also observed. Compound 14 limited the growth of E. coli (MIC50= 250 μg/mL). Interestingly, 10 was the only compound that was effective against both Gram-negative and Gram-positive bacteria. It had a MIC50 of 150 μg/mL against E. coli and S. aureus. In the presented study a group of novel antiureolytic compounds was characterised. Besides carvone stereoisomers, these are the only terpenoid urease inhibitors described so far. [ABSTRACT FROM AUTHOR]

Ephedra Herb is a crude drug defined as the terrestrial stem of Ephedra sinica, E. intermedia, or E. equisetina. It is often used to treat headaches, bronchial asthma, nasal inflammation, and the common cold. In this study, we isolated characteristic non-alkaloidal constituents from the extracts and identified them in relation to the habitat of Ephedra Herb. Extracts were prepared from Ephedra Herb collected from Inner Mongolia and Gansu. High-performance liquid chromatography was performed to quantitatively analyse the amount of ephedrine alkaloids in each extract. We compared the chemical compositions of the extracts by thin layer chromatography (TLC) to find spot characteristics depending on the habitat. 1H-NMR, 13C-NMR, and 2D-NMR spectra of the samples were also examined. The ephedrine content of all extracts satisfied the quality standard stated in the Japanese Pharmacopoeia. Nonetheless, we found each notable constituent characteristic to the Ephedra Herbs from both habitats. In order to identify them, Ephedra Herb extracts were separated by column chromatography, resulting in the isolation of (±)-α-terpineol-β-D-O-glucopyranoside (1) and (E)-7-hydroxy-3,7-dimethyloct-2-en-1-yl-β-D-O-glucopyranoside (2) as the characteristic constituents in Ephedra Herb from Inner Mongolia. Epheganoside (3), a new eudesmane-type sesquiterpene glycoside, and scopoletin (4) were found to be the characteristic constituents in Ephedra Herb from Gansu. The results obtained from this study can be used to distinguish between the habitats of Ephedra Herb. [ABSTRACT FROM AUTHOR]

Main conclusion: This review summarizes recent advances in cyanobacterial terpenoid production. The challenges and opportunities of improving terpenoid production by cyanobacteria are discussed.Terpenoids are a diverse group of natural products with a variety of commercial applications. With recent advances in synthetic biology and metabolic engineering, microbial terpenoid synthesis is being viewed as a feasible approach for industrial production. Among different microbial hosts, cyanobacteria have the potential of sustainable production of terpenoids using light and CO2. Terpene synthases and the precursor pathways have been expressed in cyanobacteria for enhanced production of various terpene hydrocarbons, including isoprene, limonene, β-phellandrene, and farnesene. However, the productivities need to be further improved for commercial production. Many barriers remain to be overcome in order to efficiently convert CO2 to terpenoids. In this review, we will summarize recent efforts on photosynthetic production of terpenoids and discuss the challenges and opportunities of engineering cyanobacteria for terpenoid bioproduction. [ABSTRACT FROM AUTHOR]

Abstract: A potential intermediate in the synthesis of several trans-clerodane natural products has been constructed employing a Diels-Alder reaction as a key-step. Two epimeric exo-adducts were formed in a 4:3 ratio in an EtAlCl2-mediated cycloaddition of O-silylated 2-vinylcyclohex-2-enol and N-tigloylisoxazolidinone. Both isomers were converted to the trans-clerodane intermediate in four steps; reductive removal of the oxazolidinone, followed by O-benzylation, removal of the silyl protecting group, and, finally, a Dess-Martin oxidation of the deprotected alcohol to the corresponding ketone. It was possible to transform both isomers from the cycloaddition into the final target, but the major isomer was converted at greater yields. An interesting discovery made during the work was that the desilylation demanded significantly different conditions depending on which isomer was deprotected. The fact that the cycloaddition not only resulted in an excellent exo-selectivity, but also that the alkene to a large extent approached from the least hindered side, opens the possibility for enantioselective synthesis of the target compound from (R) or (S) diene starting materials in the future.Graphical abstract: [ABSTRACT FROM AUTHOR]

Diaphorina citri is a vector of the bacterial causative agent of Huanglongbing (HLB = Citrus greening), a severe disease affecting citrus crops. As there is no known control for HLB, manipulating insect behaviour through deployment of semiochemicals offers a promising opportunity for protecting citrus crops. The behavioural responses of D. citri to plant volatiles, and the identity of these plant volatiles were investigated. Volatiles were collected from host plants Murraya paniculata, Citrus sinensis, C. reshni, C. limettioides, Poncirus trifoliata, and from non-host plants Psidium guajava, Mangifera indica, Anacardium occidentale. In behavioural assays, female D. citri spent more time in the arms containing volatiles from either M. paniculata or C. sinensis compared to the control arms. When D. citri was exposed to volatiles collected from A. occidentale, they preferred the control arm. Volatiles emitted from the other studied plants did not influence the foraging behaviour of D. citri. Chemical analyses of volatile extracts from C. sinensis, M. paniculata, and A. occidentale revealed the presence of the terpenoids (E)-4,8-dimethylnona-1,3,7-triene (DMNT) and (E,E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT) in higher amounts in A. occidentale. In further behavioural bioassays, female D. citri spent less time in arms containing a synthetic blend of DMNT and TMTT compared to the control arms. Female D. citri also spent less time in arms containing the synthetic blend in combination with volatile extracts from either M. paniculata or C. sinensis compared to the control arms. Results suggest that higher release of the two terpenoids by A. occidentale make this species unattractive to D. citri, and that the terpenoids could be used in reducing colonisation of citrus plants and therefore HLB infection. [ABSTRACT FROM AUTHOR]

Background: Terpenoids, the largest class of natural products in the plant kingdom, have been widely used in medicine. The precursors of terpenoids, isoprene phosphate (IPP) and dimethylallyl pyrophosphate (DMAPP), were synthesized from a mevalonate (MVA) pathway and a 2-C-methyl- d-erythritol-4-phosphate (MEP) pathway respectively. The acetyl-CoA acetyltransferase (AACT) is the initial enzyme in MVA pathway and is considered presently to be essential for terpenoid backbone biosynthesis. The basic research on cytochemistry of terpenoid metabolic enzymes is important for understanding the mechanisms underlying major metabolic processes. However, compartmentalization of AACT in plants is in controversy. Euphorbia helioscopia L. containing laticifers in the whole plant is a famous ancient folk medicine for tumor treatment, and the terpenoid is an active ingredient. Furthermore, the laticifer cell is the main synthesizing and storing site for terpenoids. Results: The gene of AACT was cloned successfully from E. helioscopia, and named as EhAACT. The EhAACT expression has no significant difference among roots, stems and leaves. However, compared with the roots and stems, the EhAACT expression level is slightly higher in leaves. In addition, EhAACT recombinant protein was expressed by procaryotic expression system and anti-EhAACT antibody was prepared, the molecular weight is about 43 kDa. Western blotting results illustrated that the EhAACT antibodies specifically recognized the endogenous proteins in E. helioscopia laticifers. At last, the subcellular localization of EhAACT in E. helioscopia laticifers was observed by using colloidal gold immune-electron microscopy. EhAACT was found to mainly distribute in the endoplasmic reticulum (ER), vacuoles originated from ER and cytosol aound vacuoles originated from ER. Conclusions: As a result, we speculated that in E. helioscopia laticifers, EhAACT located in cytosol would be transferred to small vacuoles dilated from ER, and the precursors of terpenoids were synthesized in these small vacuoles, then terpenoids were further synthesized into latex particles. This result would provide theoretical basis for regulating and controlling of terpenoid biosynthesis in laticifers. [ABSTRACT FROM AUTHOR]

Poly(dodecylmethacrylate-co-methyleugenol) P(DDMA-co-Meu) and poly(dodecylmethacrylate-co-methylchavicol) P(DDMA-co-Mch) gels were synthesized in ethanol using free radical cross-linking polymerization method at 60 °C for 24 h in the presence of azobisisobutyronitrile (AIBN) and triethylene glycol dimethacrylate (TEGDMA) as initiator and cross-linker, respectively. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the gels. These gels were used to investigate swelling behaviors in linalool and methyl eugenol, in essential oil mixture of phenyl propanoid and terpenoid, and also in various solvents. While the equilibrium swelling values (ESV) of both gels were higher in linalool than in methyl eugenol, the result was vice versa in the case of essential oil mixture. ESVs of both gels were also obtained in various solvents with different functional groups and the highest ESV of both gels were obtained in toluene, and the lowest ESV of P(DDMA-co-Meu) and P(DDMA-co-Mch) was in methanol and in ethylene glycol, respectively. While P(DDMA-co-Meu) is sensitive to carbon number change in alcohol, P(DDMA-co-Mch) is less sensitive. In the case of esters, increase of carbon number in functional group causes a more significant change in ESV than an increase of carbon number in aliphatic chain. Experimental results were correlated by the first-order and second-order models. The second-order model was more suitable than the other. While P(DDMA-co-Meu) gel swelled in linalool exhibits a Fickian diffusion character, the diffusion mechanism of the gel in methyl eugenol is a non-Fickian one. In the case of P(DDMA-co-Mch), the result is vice versa. [ABSTRACT FROM AUTHOR]

Artemisinin-based combination therapy (ACT) forms the frontline treatment of malaria. Artemisinin, an endoperoxide sesquiterpenoid lactone biosynthesized by Artemisia annua, is the effective medicine that kills malarial parasites. Due to insufficient production of artemisinin for ACT, millions of people lost their lives in past years worldwide. To solve this severe problem, numerous studies have been undertaken to understand artemisinin biosynthesis and to innovate metabolic engineering technology to increase artemisinin yield. Here, we focus on reviewing progresses achieved in understanding biosynthetic pathway, genetic breeding, metabolic engineering, and synthetic biology. Furthermore, based on current knowledge, we discuss multiple fundamental questions and challenges. [ABSTRACT FROM AUTHOR]

Main conclusion : Maize ( Zea mays ) terpene synthase 7 (ZmTPS7) was characterized as a τ-cadinol synthase, which exhibited constitutive and inducible gene expression patterns, suggesting involvement in stress response. Maize produces a variety of terpenoids involved in defense response. Despite some terpene synthases (TPSs) responsible for these terpenoids have been characterized, biosynthesis of many terpenes, particularly sesquiterpenes, which were produced in response to biotic or abiotic stress, remains largely unknown. Here, we characterized ZmTPS7 biochemically through recombinant expression in Escherichia coli and detected that it catalyzed formation of a blend of sesquiterpenes and sesquiterpenoid alcohols as the sesquiterpene synthase through GC-MS analysis. Subsequently, the major product was purified and identified as τ-cadinol through nuclear magnetic resonance spectroscopy (NMR) analysis, which was also detected in maize tissues infected by pathogen fungus for the first time. ZmTPS7 constitutively expressed in aerial tissues while with trace amount of transcript in roots. Fungus spore inoculation and methyl jasmonate (MeJA) treatment induced gene expression of ZmTPS7 in leaves, while exogenous ABA induced ZmTPS7 dramatically in roots, suggesting that ZmTPS7 might be involved in stress response. τ-cadinol was quantified in infected maize tissues with the concentration of ~200 ng/g fresh weight, however, which was much lower than the inhibitory one on two tested necrotrophic fungi. Such evidences indicate that anti-fungal activity of τ-cadinol is not physiologically relevant, and further investigation is needed to clarify its biological functions in maize. Taken together, ZmTPS7 was characterized as the τ-cadinol synthase and suggested to be involved in stress response, which also increased the diversity of maize terpenoid profile. [ABSTRACT FROM AUTHOR]

Conifer bark beetles attack and kill mature spruce and pine trees, especially during hot and dry conditions. These beetles are closely associated with ophiostomatoid fungi of the Ascomycetes, including the genera Ophiostoma, Grosmannia, and Endoconidiophora, which enhance beetle success by improving nutrition and modifying their substrate, but also have negative impacts on beetles by attracting predators and parasites. A survey of the literature and our own data revealed that ophiostomatoid fungi emit a variety of volatile organic compounds under laboratory conditions including fusel alcohols, terpenoids, aromatic compounds, and aliphatic alcohols. Many of these compounds already have been shown to elicit behavioral responses from bark beetles, functioning as attractants or repellents, often as synergists to compounds currently used in bark beetle control. Thus, these compounds could serve as valuable new agents for bark beetle management. However, bark beetle associations with fungi are very complex. Beetle behavior varies with the species of fungus, the stage of the beetle life cycle, the host tree quality, and probably with changes in the emission rate of fungal volatiles. Additional research on bark beetles and their symbiotic associates is necessary before the basic significance of ophiostomatoid fungal volatiles can be understood and their applied potential realized. [ABSTRACT FROM AUTHOR]

Total syntheses of terpenoids play an essential role in the development of synthetic organic chemistry and medicinal science. Chinese synthetic community has made more and more profound contribution to this field and has gradually grown into a major force in the world over the past years. In this review, we shall celebrate the achievement by surveying the recent terpenoid syntheses from China since 2010. [ABSTRACT FROM AUTHOR]

Novel derivatives of α-truxillic acid with a camphor framework were synthesized and evaluated for their in vivo analgesic activity. α-Truxillic acid derivatives were prepared via solvent-free photocatalyzed [2+2] cyclodimerization of ( E)-cinnamic acid. Target compounds were obtained through the substitution of -Cl or -OH groups in α-truxillic acid. The chemical structures of the synthesized compounds were elucidated by H, C-NMR, and mass spectrometry. Their analgesic activities were evaluated by the acetic acid-induced writhing test and the hot plate method. Compounds 7b and 7f containing the cyclobutane unit and natural fragments at 10 mg/kg exhibited analgesic activity in the acetic acid-induced writhing test, while α-truxillic acid (10 mg/kg, per os) did not show analgesic activity in the test. Intermediate 2 caused a decrease in the writhing with pain inhibition of 28 %. In the hot plate test, borneol showed high analgesic activity with pain inhibition of 60 %. [ABSTRACT FROM AUTHOR]

Apocarotenoids are natural compounds derived from the oxidative cleavage of carotenoids. Particularly, C-apocarotenoids are volatile compounds that contribute to the aromas of different flowers and fruits and are highly valued by the Flavor and Fragrance industry. So far, the chemical synthesis of these terpenoids has dominated the industry. Nonetheless, the increasing consumer demand for more natural and sustainable processes raises an interesting opportunity for bio-production alternatives. In this regard, enzymatic biocatalysis and metabolically engineered microorganisms emerge as attractive biotechnological options. The present review summarizes promising bioengineering approaches with regard to chemical production methods for the synthesis of two families of C-apocarotenoids: ionones/dihydroionones and damascones/damascenone. We discuss each method and its applicability, with a thorough comparative analysis for ionones, focusing on the production process, regulatory aspects, and sustainability. [ABSTRACT FROM AUTHOR]

Drought has the potential to influence the emission of biogenic volatile organic compounds (BVOCs) from forests and thus affect the oxidative capacity of the atmosphere. Our understanding of these influences is limited, in part, by a lack of field observations on mature trees and the small number of BVOCs monitored. We studied 50- to 60-year-old Pinus ponderosa trees in a semi-arid forest that experience early summer drought followed by late-summer monsoon rains, and observed emissions for five BVOCs-monoterpenes, methylbutenol, methanol, acetaldehyde and acetone. We also constructed a throughfall-interception experiment to create 'wetter' and 'drier' plots. Generally, trees in drier plots exhibited reduced sap flow, photosynthesis, and stomatal conductances, while BVOC emission rates were unaffected by the artificial drought treatments. During the natural, early summer drought, a physiological threshold appeared to be crossed when photosynthesis ≅2 μmol m s and conductance ≅0.02 mol m s. Below this threshold, BVOC emissions are correlated with leaf physiology (photosynthesis and conductance) while BVOC emissions are not correlated with other physicochemical factors (e.g., compound volatility and tissue BVOC concentration) that have been shown in past studies to influence emissions. The proportional loss of C to BVOC emission was highest during the drought primarily due to reduced CO assimilation. It appears that seasonal drought changes the relations among BVOC emissions, photosynthesis and conductance. When drought is relaxed, BVOC emission rates are explained mostly by seasonal temperature, but when seasonal drought is maximal, photosynthesis and conductance-the physiological processes which best explain BVOC emission rates-decline, possibly indicating a more direct role of physiology in controlling BVOC emission. [ABSTRACT FROM AUTHOR]

Plant terpenoids are among the most diverse group of naturally-occurring organic compounds known, and several are used in contemporary consumer products. Terpene synthase enzymes catalyze complex rearrangements of carbon skeleton precursors to yield thousands of unique chemical structures that range in size from the simplest five carbon isoprene unit to the long polymers of rubber. Such chemical diversity has established plant terpenoids as valuable commodity chemicals with applications in the pharmaceutical, neutraceutical, cosmetic, and food industries. More recently, terpenoids have received attention as a renewable alternative to petroleum-derived fuels and as the building blocks of synthetic biopolymers. However, the current plant- and petrochemical-based supplies of commodity terpenoids have major limitations. Photosynthetic microorganisms provide an opportunity to generate terpenoids in a renewable manner, employing a single consolidated host organism that is able to use solar energy, HO and CO as the primary inputs for terpenoid biosynthesis. Advances in synthetic biology have seen important breakthroughs in microbial terpenoid engineering, traditionally via fermentative pathways in yeast and Escherichia coli. This review draws on the knowledge obtained from heterotrophic microbial engineering to propose strategies for the development of microbial photosynthetic platforms for industrial terpenoid production. The importance of utilizing the wealth of genetic information provided by nature to unravel the regulatory mechanisms of terpenoid biosynthesis is highlighted. [ABSTRACT FROM AUTHOR]

The acaricidal activities of solvent extracts and essential oil obtained from Cryptomeria japonica were investigated. The two target spider mites ( Tetranychus kanzawai and T. urticae), are known pests for various crops. The C. japonica leaves, barks, and heartwood were extracted by hexane, ethyl acetate and methanol successively, and acaricidal activities were tested by the leaf disc method. Acaricidal activity was observed on a hexane extract of C. japonica leaves. Next, the acaricidal activities of essential oil obtained from leaves by hot water distillation was tested and found to show stronger effects than the hexane extract. Elemol and ent-kaurene were found as the active components of essential oil. The LC values of ent-kaurene were quite lower than those of elemol and essential oil. Acaricidal activities of essential oil were mainly caused by ent-kaurene. Since other chemotypes of C. japonica are known in major diterpene hydrocarbon, we examined the acaricidal activity of phyllocladene and ent-sclarene. The activity of ent-sclarene was lower than ent-kaurene, and phyllocladene was much lower than ent-sclarene. Thus, the extract of C. japonica leaves containing ent-kaurene could be used as an interim pesticide when commercial pesticides are being changed or as a matrix of commercial pesticide. [ABSTRACT FROM AUTHOR]

In different plant species, secondary metabolite biosynthesis is regulated by the phytohormone jasmonic acid (JA), which is derived by the action of lipoxygenase. In this study, we examined mono- and sesquiterpenoid accumulation and the related signal transduction pathways and biosynthetic genes in adventitious root cultures of Panax ginseng C.A. Meyer as induced by yeast extract (YE, 3 g/L), a biotic elicitor, and salicylic acid (SA, 200 μM), a signaling elicitor. The lipoxygenase ( LOX) gene was highly expressed in 24 and 12 h after treatment with SA and YE. JA content was significantly increased in 24 h after SA treatment. The HO content was the highest in 24 and 72 h after the onset of SA and YE treatment, respectively. RNA blot analysis showed that farnesyl diphosphate synthase ( FPS) and isopentenyl pyrophosphate isomerase ( IPPI) genes encoding enzymes of the biosynthesis of mono- and sesquiterpenoids were up-regulated by both elicitors. Farensol, isochiapin B sesquiterpenoids, champhor, and cineole monoterpenoids were highly accumulated after 24 h of SA treatment, while YE treatment induced bacchotricuneatin C, guaiazulene, isochiapin B, and p-benzoquinone sesquiterpenoid production. These results suggest that mono- and sesquiterpenoid accumulation induced by SA and YE occurs due to the IPPI and FPS expression and may be mediated by reactive oxygen species signaling and jasmonic acid signal transduction. [ABSTRACT FROM AUTHOR]

Plant responses of both shoots and roots to combined abiotic and biotic stress have been rarely investigated. However, stresses such as drought and aboveground herbivory might lead to conflicting resource allocation patterns and pronounced shifts in shoot vs. root defenses. In the present study, the effects of water availability and leaf herbivory by caterpillars of a generalist on various shoot and root traits of the aromatic plant Tanacetum vulgare L. were investigated. This species contains terpenoids in leaves and roots, which can differ in composition among individuals, forming so-called chemotypes. To test for intraspecific variation, responses were investigated in two chemotypes, the thujone and the carvyl acetate chemotype. Furthermore, effects of differences in plant quality on the herbivores were studied. Shoot biomass significantly decreased due to drought and herbivory, whereas the root/shoot ratio increased following drought but was unaffected by herbivory. No shifts in C/N ratios were found. In contrast to our expectation, leaf terpenoid concentrations decreased only slightly due to drought, whereas root terpenoids were significantly induced by both drought and herbivory. Chemotypes showed distinct responses to drought at least in the root/shoot ratio, with a higher drought sensitivity of the carvyl acetate chemotype. The body mass of the caterpillars was unaffected by the irrigation treatment but depended on chemotype and terpenoid concentration of the plants. Thus, both qualitative and quantitative defenses strongly affect herbivore development. The present results offer new insights into the above- and belowground organ-specific responses of plants. They highlight the importance of roots in response to various environmental challenges. [ABSTRACT FROM AUTHOR]

The Diels-Alder (D-A) reaction is one of the most powerful reactions in organic synthesis. The intermolecular D-A reaction attracts much less attentions than its intramolecular counterpart in natural product synthesis, possibly due to the issues of reactivity and selectivity. In the past decade, the intermolecular D-A reaction has been increasingly utilized in the total synthesis of structurally complex natural products. In this article, we present a few examples for the elegant applications of the intermolecular D-A reaction that are inspired by biosynthetic hypotheses of the target natural products. These examples demonstrate that D-A reaction is not only useful for preparing building blocks but also powerful for coupling structurally complicated and sterically demanding segments in a highly chemo- and stereo-controlled fashion, which may inspire further developments of intermolecular D-A reaction from both strategy and methodology perspectives. [ABSTRACT FROM AUTHOR]

A new series of chiral heterocyclic compounds with frameworks of different types were synthesized by reactions of verbenol epoxide with aromatic aldehydes in the presence of montmorillonite clay. The analgesic activity of compounds with frameworks of 2-aryl-4,4,7-trimethyl-4a,5,8,8a-tetrahydro-4 H-benzo[ d][1,3]dioxin-8-ol type was studied in vivo. The majority of these compounds showed a significant analgesic activity in the acetic acid-induced writhing test; two compounds also showed analgesic activity in the hot-plate test. ED in acetic acid-induced writhing test for compound where aryl is 4-chlorophenyl substituent was determined to be 4.5 mg/kg. Compound with 4-nitrophenyl substituent demonstrated high analgesic activity in both tests. [ABSTRACT FROM AUTHOR]

The essential oil (EO) of Lavandula is dominated by monoterpenes, but can also contain small amounts of sesquiterpenes, depending on species and environmental conditions. For example, the sesquiterpene 9-epi-caryophyllene can make up to 8 % of the EO in a few species, including those commercially propagated for EO production. Here, we report the cloning and functional characterization of 9-epi-caryophyllene synthase ( LiCPS) from the glandular trichomes of Lavandula x intermedia, cv. Grosso. The 1,617 bp open reading frame of LiCPS, which did not encode a transit peptide, was expressed in Escherichia coli and the recombinant protein purified by Ni-NTA agarose affinity chromatography. The ca. 60 kDa recombinant protein specifically converted farnesyl diphosphate to 9-epi-caryophyllene. LiCPS also produced a few monoterpenes when assayed with the monoterpene precursor geranyl diphosphate (GPP), but-unlike most monoterpene synthases-was not able to derive detectable amounts of any products from the cis isomer of GPP, neryl diphosphate. The LiCPS transcripts accumulated in developing L. x intermedia flowers and were highly enriched in glandular trichomes, but were not detected in leaves suggesting that the transcriptional expression of this gene is spatially and developmentally regulated. [ABSTRACT FROM AUTHOR]

A set of new heterocyclic compounds with different types of framework, including a new type of framework, were synthesized by reactions of verbenol epoxide and (1 R,2 R,6 S)-3-methyl-6-(prop-1-en-2-yl)cyclohex-3-ene-1,2-diol with aromatic aldehydes containing three methoxy groups. The analgesic activity of these substances was studied. Three compounds possessed considerable activity in vivo in the acetic acid-induced writhing test. (2 S,4 R,4a R,8 S,8a R)-4,7-Dimethyl-2-(2,4,5-trimethoxyphenyl)-3,4,4a,5,8,8a-hexahydro-2 H-4,8-epoxychromene exhibited high analgesic activity in both acetic acid-induced writhing and hot plate tests; its selectivity index IS exceeded 60. [ABSTRACT FROM AUTHOR]

Citral is a linear monoterpene which is present, as a volatile component, in the essential oil of several different aromatic plants. Previous studies have demonstrated the ability of citral to alter the mitotic microtubules of plant cells, especially at low concentrations. The changes to the microtubules may be due to the compound acting directly on the treated root and coleoptile cells or to indirect action through certain phytohormones. This study, performed in Arabidopsis thaliana, analysed the short-term effects of citral on the auxin content and mitotic cells, and the long-term effects of these alterations on root development and ethylene levels. The results of this study show that citral alters auxin content and cell division and has a strong long-term disorganising effect on cell ultra-structure in A. thaliana seedlings. Its effects on cell division, the thickening of the cell wall, the reduction in intercellular communication, and the absence of root hairs confirm that citral is a strong phytotoxic compound, which has persistent effects on root development. [ABSTRACT FROM AUTHOR]

Many terpenes and terpenoid compounds are known as bioactive substances with desirable fragrance and medicinal activities. Modification of such compounds to yield new derivatives with desired properties is particularly attractive. Cytochrome P450 monooxygenases are potential enzymes for these reactions due to their capability of performing different reactions on a variety of substrates. We report here the characterization of CYP264B1 from Sorangium cellulosum So ce56 as a novel sesquiterpene hydroxylase. CYP264B1 was able to convert various sesquiterpenes including nootkatone and norisoprenoids (α-ionone and β-ionone). Nootkatone, an important grapefruit aromatic sesquiterpenoid, was hydroxylated mainly at position C-13. The product has been shown to have the highest antiproliferative activity compared with other nootkatone derivatives. In addition, CYP264B1 was found to hydroxylate α- and β-ionone, important aroma compounds of floral scents, regioselectively at position C-3. The products, 3-hydroxy-β-ionone and 13-hydroxy-nootkatone, were confirmed by H and C NMR. The kinetics of the product formation was analyzed by high-performance liquid chromatography, and the K and k values were calculated. The results of docking α-/β-ionone and nootkatone into a homology model of CYP264B1 revealed insights into the structural basis of these selective hydroxylations. [ABSTRACT FROM AUTHOR]

Picrorhiza ( Picrorhiza kurrooa) is an endangered medicinal plant with well-known hepatoprotective activity attributed to monoterpenoid picrosides. The present article details on regulatory genes of terpenoid metabolism, 3-hydroxy-3-methylglutaryl coenzyme A reductase ( pkhmgr) and 1-deoxy-D-xylulose-5-phosphate synthase ( pkdxs) from picrorhiza. Since no molecular information was available, these genes were cloned to full-length by degenerate primers and rapid amplification of cDNA ends, followed by cloning of the upstream sequences that showed the presence of core sequences for light and temperature responsiveness. Electrophoretic mobility shift assay confirmed binding of protein to these motifs. Expression of pkhmgr and pkdxs was up-regulated at 15°C as compared to at 25°C as well as under light as compared to dark conditions. Picrosides content exhibited the trend similar to gene expression. To rule out the possible limitation of carbon pool under dark condition, plantlets of picrorhiza were raised in vitro in Murashige and Skoog medium supplemented with 3% sucrose. Results showed similar up-regulation of both the genes and the higher picrosides content in in vitro raised plantlets in the presence of light. Data suggested the important roles played by light and temperature in regulating pkhmgr and pkdxs, and the picrosides level in picrorhiza. [ABSTRACT FROM AUTHOR]

Engineering biosynthetic pathways in heterologous microbial host organisms offers an elegant approach to pathway elucidation via the incorporation of putative biosynthetic enzymes and characterization of resulting novel metabolites. Our previous work in Escherichia coli demonstrated the feasibility of a facile modular approach to engineering the production of labdane-related diterpene (20 carbon) natural products. However, yield was limited (<0.1 mg/L), presumably due to reliance on endogenous production of the isoprenoid precursors dimethylallyl diphosphate and isopentenyl diphosphate. Here, we report incorporation of either a heterologous mevalonate pathway (MEV) or enhancement of the endogenous methyl erythritol phosphate pathway (MEP) with our modular metabolic engineering system. With MEP pathway enhancement, it was found that pyruvate supplementation of rich media and simultaneous overexpression of three genes ( idi, dxs, and dxr) resulted in the greatest increase in diterpene yield, indicating distributed metabolic control within this pathway. Incorporation of a heterologous MEV pathway in bioreactor grown cultures resulted in significantly higher yields than MEP pathway enhancement. We have established suitable growth conditions for diterpene production levels ranging from 10 to >100 mg/L of E. coli culture. These amounts are sufficient for nuclear magnetic resonance analyses, enabling characterization of enzymatic products and hence, pathway elucidation. Furthermore, these results represent an up to >1,000-fold improvement in diterpene production from our facile, modular platform, with MEP pathway enhancement offering a cost effective alternative with reasonable yield. Finally, we reiterate here that this modular approach is expandable and should be easily adaptable to the production of any terpenoid natural product. [ABSTRACT FROM AUTHOR]