Search

The structural, conformational, and spectroscopic properties in the gas phase of 20 bicyclic monoterpenes and monoterpenoids have been analyzed by a new accurate, reduced-cost computational strategy. In detail, the revDSD-PBEP86 double-hybrid functional in conjunction with the D3BJ empirical dispersion corrections and a suitable triple-zeta basis set provides accurate geometrical parameters, whence equilibrium rotational constants, which are further improved by proper account of core–valence correlation. Average deviations within 0.1% between computed and experimental rotational constants are reached when taking into account the vibrational corrections obtained by the B3LYP functional in conjunction with a double-zeta basis set in the framework of second-order vibrational perturbation theory. In addition to their intrinsic interest, the studied terpenes further extend the panel of systems for which the proposed strategy has provided accurate results at density functional theory cost. Therefore, a very accurate yet robust and user-friendly tool is now available for systematic investigations of the role of stereo-electronic effects on the properties of large systems of current technological and/or biological interest by experimentally oriented researchers. [ABSTRACT FROM AUTHOR]

Mycobacterium tuberculosis (Mtb) releases the unusual terpene nucleoside 1-tuberculosinyladenosine (1-TbAd) to block lysosomal function and promote survival in human macrophages. Using conventional approaches, we found that genes Rv3377c and Rv3378c, but not Rv3376, were necessary for 1-TbAd biosynthesis. Here, we introduce linear models for mass spectrometry (limms) software as a next-generation lipidomics tool to study the essential functions of lipid biosynthetic enzymes on a whole-cell basis. Using limms, whole-cell lipid profiles deepened the phenotypic landscape of comparative mass spectrometry experiments and identified a large family of approximately 100 terpene nucleoside metabolites downstream of Rv3378c. We validated the identity of previously unknown adenine-, adenosine-, and lipid-modified tuberculosinol-containing molecules using synthetic chemistry and collisional mass spectrometry, including comprehensive profiling of bacterial lipids that fragment to adenine. We tracked terpene nucleoside genotypes and lipid phenotypes among Mycobacterium tuberculosis complex (MTC) species that did or did not evolve to productively infect either human or nonhuman mammals. Although 1-TbAd biosynthesis genes were thought to be restricted to the MTC, we identified the locus in unexpected species outside the MTC. Sequence analysis of the locus showed nucleotide usage characteristic of plasmids from plant-associated bacteria, clarifying the origin and timing of horizontal gene transfer to a pre-MTC progenitor. The data demonstrated correlation between high level terpene nucleoside biosynthesis and mycobacterial competence for human infection, and 2 mechanisms of 1-TbAd biosynthesis loss. Overall, the selective gain and evolutionary retention of tuberculosinyl metabolites in modern species that cause human TB suggest a role in human TB disease, and the newly discovered molecules represent candidate disease-specific biomarkers.

In pharmaceutical discovery, the "magic methyl" effect describes a substantial improvement in the pharmacological properties of a drug candidate with the incorporation of methyl groups. Therefore, to expedite the synthesis of methylated drug analogs, late-stage, undirected methylations of C(sp3)-H bonds in complex molecules would be valuable. However, current methods for site-selective methylations are limited to activated C(sp3)-H bonds. Here we describe a site-selective, undirected methylation of unactivated C(sp3)-H bonds, enabled by photochemically activated peroxides and a nickel(II) complex whose turnover is enhanced by an ancillary ligand. The methodology displays compatibility with a wide range of functional groups and a high selectivity for tertiary C-H bonds, making it suitable for the late-stage methylation of complex organic compounds that contain multiple alkyl C-H bonds, such as terpene natural products, peptides, and active pharmaceutical ingredients. Overall, this method provides a synthetic tool to explore the "magic methyl" effect in drug discovery.

The production of e-cigarette aerosols through vaping processes is known to cause the formation of various free radicals and reactive oxygen species (ROS). Despite the well-known oxidative potential and cytotoxicity of fresh vaping emissions, the effects of chemical aging on exhaled vaping aerosols by indoor atmospheric oxidants are yet to be elucidated. Terpenes are commonly found in e-liquids as flavor additives. In the presence of indoor ozone (O3), e-cigarette aerosols that contain terpene flavorings can undergo chemical transformations, further producing ROS and reactive carbonyl species. Here, we simulated the aging process of the e-cigarette emissions in a 2 m3 FEP film chamber with 100 ppbv of O3 exposure for an hour. The aged vaping aerosols, along with fresh aerosols, were collected to detect the presence of ROS. The aged particles exhibited 2- to 11-fold greater oxidative potential, and further analysis showed that these particles formed a greater number of radicals in aqueous conditions. The aging process induced the formation of various alkyl hydroperoxides (ROOH), and through iodometric quantification, we saw that our aged vaping particles contained significantly greater amounts of these hydroperoxides than their fresh counterparts. Bronchial epithelial cells exposed to aged vaping aerosols exhibited an upregulation of the oxidative stress genes, HMOX-1 and GSTP1, indicating the potential for inhalation toxicity. This work highlights the indirect danger of vaping in environments with high ground-level O3, which can chemically transform e-cigarette aerosols into new particles that can induce greater oxidative damage than fresh e-cigarette aerosols. Given that the toxicological characteristics of e-cigarettes are mainly associated with the inhalation of fresh aerosols in current studies, our work may provide a perspective that characterizes vaping exposure under secondhand or thirdhand conditions as a significant health risk.

A simple aqueous host:guest sensing array can selectively discriminate between different types of citrus varietal from peel extract samples. It can also distinguish between identical citrus samples at varying stages of ripening. The discrimination effects stem from detection of changes in the terpenoid composition of the peel extracts by the host:guest array, despite the overwhelming excess of a single component, limonene, in each sample. The hosts are insensitive to limonene but bind other monoterpenes strongly, even though they are similar in structure to the major limonene component. This work demonstrates the capability of host:guest arrays in sensing target molecules in environments with the competing agents present at high abundances in the sample matrix.

Reduced defense against large herbivores has been suggested to be part of the island syndrome in plants. However, empirical evidence for this pattern is mixed. In this paper, we present two studies that compare putative physical and chemical defense traits from plants on the California Channel Islands and nearby mainland based on sampling of both field and common garden plants. In the first study, we focus on five pairs of woody shrubs from three island and three mainland locations and find evidence for increased leaf area, decreased marginal leaf spines, and decreased concentrations of cyanogenic glycosides in island plants. We observed similar increases in leaf area and decreases in defense traits when comparing island and mainland genotypes grown together in botanic gardens, suggesting that trait differences are not solely driven by abiotic differences between island and mainland sites. In the second study, we conducted a common garden experiment with a perennial herb-Stachys bullata (Lamiaceae)-collected from two island and four mainland locations. Compared to their mainland relatives, island genotypes show highly reduced glandular trichomes and a nearly 100-fold reduction in mono- and sesquiterpene compounds from leaf surfaces. Island genotypes also had significantly higher specific leaf area, somewhat lower rates of gas exchange, and greater aboveground biomass than mainland genotypes across two years of study, potentially reflecting a broader shift in growth habit. Together, our results provide evidence for reduced expression of putative defense traits in island plants, though these results may reflect adaptation to both biotic (i.e., the historical absence of large herbivores) and climatic conditions on islands.

Marine-derived Streptomyces have long been recognized as a source of novel, pharmaceutically relevant natural products. Among these bacteria, the MAR4 clade within the genus Streptomyces has been identified as metabolically rich, yielding over 93 different compounds to date. MAR4 strains are particularly noteworthy for the production of halogenated hybrid isoprenoid natural products, a relatively rare class of bacterial metabolites that possess a wide range of biological activities. MAR4 genomes are enriched in vanadium haloperoxidase and prenyltransferase genes, thus accounting for the production of these compounds. Functional characterization of the enzymes encoded in MAR4 genomes has advanced our understanding of halogenated, hybrid isoprenoid biosynthesis. Despite the exceptional biosynthetic capabilities of MAR4 bacteria, the large body of research they have stimulated has yet to be compiled. Here we review 35 years of natural product research on MAR4 strains and update the molecular diversity of this unique group of bacteria.

Monoterpenes are commonly known for their role in the flavors and fragrances industry and are also gaining attention for other uses like insect repellant and as potential renewable fuels for aviation. Corynebacterium glutamicum, a Generally Recognized as Safe microbe, has been a choice organism in industry for the annual million ton-scale bioproduction of amino acids for more than 50 years; however, efforts to produce monoterpenes in C. glutamicum have remained relatively limited. In this study, we report a further expansion of the C. glutamicum biosynthetic repertoire through the development and optimization of a mevalonate-based monoterpene platform. In the course of our plasmid design iterations, we increased flux through the mevalonate-based bypass pathway, measuring isoprenol production as a proxy for monoterpene precursor abundance and demonstrating the highest reported titers in C. glutamicum to date at 1504.6 mg/L. Our designs also evaluated the effects of backbone, promoter, and GPP synthase homolog origin on monoterpene product titers. Monoterpene production was further improved by disrupting competing pathways for isoprenoid precursor supply and by implementing a biphasic production system to prevent volatilization. With this platform, we achieved 321.1 mg/L of geranoids, 723.6 mg/L of 1,8-cineole, and 227.8 mg/L of linalool. Furthermore, we determined that C. glutamicum first oxidizes geraniol through an aldehyde intermediate before it is asymmetrically reduced to citronellol. Additionally, we demonstrate that the aldehyde reductase, AdhC, possesses additional substrate promiscuity for acyclic monoterpene aldehydes.

Terpenes are diverse specialized metabolites naturally found within plants and have important roles in inter-species communication, adaptation and interaction with the environment. Their industrial applications span a broad range, including fragrances, flavors, cosmetics, natural colorants to agrochemicals and therapeutics, yet formal chemical synthesis is economically challenging due to structural complexities. Engineering terpene biosynthesis could represent an alternative in microbial biotechnological workhorses, such as Saccharomyces cerevisiae or Escherichi coli, utilizing sugars or complex media as feedstocks. Host species that metabolize renewable and affordable carbon sources may offer unique sustainable biotechnological alternatives. Methylotrophs are bacteria with the capacity to utilize one-carbon feedstocks, such as methanol or formate. They colonize the phyllosphere (above-ground area) of plants, and many accumulate abundant carotenoid pigments. Methylotrophs have the capacity to take up and use a subset of the rare earth elements known as lanthanides. These metals can enhance one-carbon (methylotrophic) metabolism. Here, we investigated whether manipulating the metabolism enables and enhances terpene production. A carotenoid-deficient mutant potentially liberates carbon, which may contribute to bioproduct accumulation. To test this hypothesis, terpene-producing bacterial strains regulated by two distinct promoters were generated. Wildtype Methylobacterium extorquens, ∆Meta1_3665, a methylotrophic mutant lacking the carotenoid pathway, and an E. coli strain were transformed with an exogenous terpene pathway and grown both in the presence and absence of lanthanides. The extraction, and the comparison of analytical profiles, provided evidence that engineered cultured M. extorquens under control of a native, inducible methylotrophic promoter can yield the sesquiterpene patchoulol when supplemented with lanthanide. In contrast, using a moderate-strength constitutive promoter failed to give production. We demonstrated colonization of the phyllosphere with the engineered strains, supporting the future engineering of selected species of the plant microbiome and with promising implications for the synthetic biology of small molecules.

The resident human skin microbiome is responsible for the production of most of the human scents that are attractive to mosquitoes. Hence, engineering the human skin microbiome to synthesize less of mosquito attractants or produce repellents could potentially reduce bites and prevent the transmission of deadly mosquito-borne pathogens. In order to further characterize the human skin volatilome, we quantified the major volatiles of 39 strains of skin commensals (Staphylococci and Corynebacterium). Importantly, to validate the behavioral activity of these volatiles, we first assessed landing behavior triggered by human skin volatiles. We demonstrated that landing behavior is gated by the presence of carbon dioxide and L-(+)-lactic acid. This is similar to the combinatorial coding triggering mosquito short range attraction. Repellency behavior to selected skin volatiles and terpenes was tested in the presence of carbon dioxide and L-(+)-lactic acid. In a 2-choice landing behavior context, the skin volatiles 2- and 3-methyl butyric acids reduced mosquito landing by 62.0-81.6% and 87.1-99.6%, respectively. Similarly, the terpene geraniol was capable of reducing mosquito landing behavior by 74.9%. We also tested the potential repellency effects of terpenes in mosquitoes at short-range using a 4-port olfactometer. In these assays, geraniol reduced mosquito attraction (69-78%) to a mixture of key human kairomones carbon dioxide, L-(+)-lactic acid, and ammonia. These findings demonstrate that carbon dioxide and L-(+)-lactic acid change the valence of other skin volatiles towards mosquito landing behavior. Moreover, this study offers candidate odorants to be targeted in a novel strategy to reduce attractants or produce repellents by the human skin microbiota that may curtail mosquito bites, and subsequent mosquito-borne disease.

The synthesis of housane derivatives from cyclopropenes is described. Under rhodium(II) catalysis, cyclopropenylvinyl carbinols can regioselectively generate a carbene intermediate which undergoes an intramolecular cyclopropanation to form a housane, a skeleton with similar ring strain as the cyclopropene precursor. The procedure shows a remarkable broad scope and efficiency. Moreover, the method served to prepare man‐made housane‐containing terpene derivatives, which are not accessible by Nature. [ABSTRACT FROM AUTHOR]

Floral mimics deceive their pollinators by developing visual and olfactory resemblance to various models. We report a flower that exhibits phenotypes like aerial litter and deceives an aerial litter specialist beetle to achieve pollination. We assessed the floral phenology and the effective pollinators of an Australian understorey treelet, Meiogyne heteropetala (Annonaceae). The similarities of morphology, colour and odour between the flowers and co‐occurring aerial litter were investigated. The terpene synthase involved in floral scent emission was identified by expression patterns and product profile. The behavioural responses of the pollinator to various odours were assessed using bioassays. The erotylid beetle Loberus sharpi is the most likely effective pollinator because it was the only pollen‐laden visitor during the pistillate phase. Loberus sharpi was exclusively found in aerial litter and M. heteropetala flowers. The flowers offer an honest shelter reward. The beetle also oviposits there, but most larvae eventually perished as the petals dropped onto the forest floor. The morphology and spectral reflectance of the flowers overlap with aerial litter. The floral scent was dominated by monoterpenes, especially 1,8‐cineole. The cineole synthase MhCINS was the only highly expressed floral terpene synthase and possessed a highly similar product profile to the floral scent composition. The volatile composition of M. heteropetala flowers is distinct from other congeners and highly similar to aerial litter, indicating advergence to aerial litter. Visual and odour resemblance, coupled with low larval survivorship, provides evidence that the beetles were deceived into pollinating the flowers. Behavioural experiments showed that the pollinator was attracted to both aerial litter and M. heteropetala flowers. The beetles were also attracted to 1,8‐cineole and synthetic mixes of floral odour and MhCINS products. The beetles were unable to distinguish floral scent from MhCINS products nor from 1,8‐cineole, suggesting MhCINS alone sufficed to attract the pollinator olfactorily. The beetles, however, preferred aerial litter over flowers. The beetles likely categorised the flower as a general, but not the most preferred, brood substrate. Synthesis. This study reports the first case of floral mimicry of aerial litter and characterises the biochemical process responsible for olfactory mimicry. [ABSTRACT FROM AUTHOR]

Invasive pathogens threaten the sustainability of forest ecosystems globally. Trees possess intrinsic pathogen defence mechanisms, including major gene resistance (MGR) and quantitative disease resistance (QDR). Plant‐symbiotic fungi can enhance tree defences, generating far‐reaching ecosystem impacts. However, the specific contributions of various fungal guilds to this symbiont‐mediated resistance remain unclear. In this study, we inoculated six Pinus monticola seedling families exhibiting resistance (MGR or QDR) or high susceptibility to the introduced invasive pathogen Cronartium ribicola, the causative agent of white pine blister rust (WPBR), with endophytic and ectomycorrhizal fungi, either alone or in combination (symbiont treatments), in an open‐air greenhouse study. Over a period of 25 months, we monitored the growth, foliar terpene defences, and disease progression in trees before and after C. ribicola infection and in trees inoculated with the symbionts but never inoculated with C. ribicola. We observed enhanced inducible host defences and evidence of defensive priming in response to symbiont treatments. In WPBR‐free control treatments, differences in pine defences coincided with an increased seedling growth rate. For WPBR‐infected seedlings, symbiont treatments reduced disease symptoms in seedlings with QDR and to a lesser extent in susceptible families, but not in those with MGR. Furthermore, disease symptoms correlated with variations in terpene composition. Synthesis and applications: Interactions with fungal symbionts should be considered when breeding native trees for resistance against invasive pathogens. Our study underscores the capacity of endophytic and ectomycorrhizal fungi to enhance tree growth and defence while also reducing disease symptoms. We also show that fungi can induce long‐lasting changes in conifer foliar terpenes, suggesting potential applications in tree protection from invasive pathogens. [ABSTRACT FROM AUTHOR]

Cordyceps militaris is a filamentous fungus used for both medicinal and culinary purposes. It exhibits a wide range of pharmacological activities due to its valuable contents of cordycepin, polysaccharides, carotenoids, terpenoids and other metabolites. However, C. militaris strains are highly susceptible to irreversible degradation in agricultural production, which is often manifested as a prolonged color change period and a significant decrease in the production of secondary metabolites. UDP-glycosyltransferases are an important enzyme family that participates in the synthesis of terpenoids by performing the glycosylation of key residues of enzymes or molecules. However, few studies have focused on its effect on the regulation of metabolite production in C. militaris. Therefore, in this study, we performed transcriptome analysis across four different developmental stages of C. militaris to target the putative glycosyltransferase gene CmUGT1, which plays important roles in metabolite production. We further constructed and screened a CmUGT1 -overexpressing strain by Agrobacterium tumefaciens -mediated infestation of C. militaris spores. The major metabolite production of the wild-type and CmUGT1 -overexpressing C. militaris strains was determined after short-term shake-flask cultivation of mycelia. The results showed that the yields of carotenoids and polysaccharides in the mycelia of the CmUGT1 -overexpressing strains were 3.8 and 3.4 times greater than those in the mycelia of the wild type, respectively (p < 0.01). The levels of intracellular and extracellular cordycepin produced by the overexpression strain were 4.4 and 8.0 times greater than those produced by the wild-type strain (p < 0.01). This suggests that the overexpression of CmUGT1 in C. militaris enhances the synthesis activities of the main enzymes related to metabolite production, which provides a guide for obtaining excellent recombinant strains of C. militaris. [ABSTRACT FROM AUTHOR]

A mild and highly selective hydrosilylation method was employed to synthesize five novel well-defined Janus ring siloxanes bearing terpenes and terpenoids, which are the main bioactive components of essential oils. The characterization of these new bio-sourced molecular materials, derived from hydrosilyl-substituted all-cis-cyclotetrasiloxane, was conducted through comprehensive analyses using multinuclear NMR, infrared spectroscopy, elemental analysis, and mass spectroscopy. The thermal stability of the newly synthesized Janus rings was investigated, and the siloxane skeleton was shown to confer an enhanced thermal stability compared with free terpenes and terpenoids. [ABSTRACT FROM AUTHOR]

The zoophytophagous mirid predator Nesidiocoris tenuis and the ectoparasitoid Stenomesius japonicus are important biological control agents for several agricultural pests including the invasive leafminer, Phthorimaea absoluta, a destructive pest of Solanaceous crops especially tomato in sub-Saharan Africa. However, little is known about how feeding by N. tenuis can influence the tritrophic interactions in the tomato plant. Here, we tested the hypothesis that N. tenuis phytophagy would influence the tritrophic olfactory interactions between the host plant tomato and pest, predator, and parasitoid. In olfactometer assays, P. absoluta females and N. tenuis adults were both attracted to constitutive volatiles released by the tomato plant. Whereas females of P. absoluta avoided volatiles released by N. tenuis-infested plants, S. japonicus females and N. tenuis adults were attracted to the induced volatiles. In coupled gas chromatography-electroantennographic detection (GC-EAD) recordings of intact and N. tenuis-infested plant volatiles, antennae of P. absoluta and S. japonicus females both detected eight components, whereas N. tenuis adults detected seven components which were identified by GC-mass spectrometry (GC-MS) as terpenes and green leaf volatiles (GLVs). Dose-response olfactometer bioassays revealed that the responses of P. absoluta, N. tenuis, and S. japonicus varied with the composition and concentration of blends and individual compounds tested from N tenuis-induced volatiles. Females of P. absoluta showed no preference for an eight-component blend formulated from the individual repellents including hexanal, (Z)-3-hexenyl butanoate, and δ-elemene identified in the volatiles. On the other hand, S. japonicus females were attracted to an eight-component blend including the attractants (E)-2-hexenal, (Z)-3-hexenol, methyl salicylate, β-phellandrene, and (E)-caryophyllene. Likewise, N. tenuis adults were attracted to a seven-component blend including the attractants β-phellandrene, δ-elemene, and (E)-caryophyllene identified in the volatiles. Our findings suggest that there is potential for the use of terpenes and GLVs to manage the insects in the tritrophic interaction. [ABSTRACT FROM AUTHOR]

Aim: Geraniol is an acyclic monoterpenoid that is abundant in many plants, including rose, lemongrass, and lavender. As geraniol has various beneficial functions, rose oil rich in geraniol is not only used for aromatherapy but also as a supplement to promote health benefits. However, the beneficial effects of geraniol on age‐related pathologies are unknown. In this study, we aimed to clarify the effects of geraniol intake on age‐related pathologies. Methods: We orally administered geraniol to aged mice (age: 24–29 months) five times a week for 4 weeks and sampled their blood and various organs. We investigated age‐related changes in the blood and organ samples. Furthermore, we treated HepG2 cells with geraniol and examined the expression level of the ALB gene and the amount of secreted albumin in vitro. Results: Geraniol significantly increased blood albumin, total cholesterol, and red blood cell counts, indicating an improvement in nutritional markers in aged mice. Geraniol also transcriptionally increased the Alb gene expression in the liver of aged mice. Furthermore, treatment with geraniol significantly upregulated the ALB gene expression and the secretion of albumin in the conditioned medium of HepG2 cells. Conclusion: Geraniol increases serum albumin levels at the transcriptional level. Geraniol intake can be an effective strategy for age‐related malnutrition. Geriatr Gerontol Int 2024; 24: 1233–1240. [ABSTRACT FROM AUTHOR]

• Strychnos henningsii extracts showed high antioxidant and low cytotoxicity. • Methanolic extract inhibited α-glucosidase; alkaloid extract inhibited α-amylase. • Alkaloids were the highest phytochemical content, followed by flavonoids, phenols, and terpenes. • Five bioactive triterpenes showed low to moderate cytotoxicity and enzyme inhibition. The pervasiveness of diabetes mellitus, particularly type II diabetes, is escalating in South Africa, where complications from this condition rank as the second leading cause of natural mortality. Locally, the bark of Strychnos henningsii Gilg. has been traditionally employed to manage type II diabetes, a chronic ailment necessitating continuous attention. This study aims to assess the cytotoxic, antioxidant, and antidiabetic enzyme inhibitory potentials of S. henningsii , based on its perceived antidiabetic properties. The investigation involved HPTLC, UV–vis spectrophotometry, and LC-MS analyses to ascertain the phytochemical composition. In vitro MTT cytotoxicity, DPPH radical scavenging, ORAC, α-glucosidase and α-amylase inhibition were evaluated on the methanolic (MSHB) and total tertiary alkaloid crude extracts (TTA SHB) of S. henningsii. Furthermore, five bioactive pentacyclic triterpenes isolated from S. henningsii were evaluated for their cytotoxicity and antidiabetic enzymatic potential. The phytochemical examination showed a notable occurrence of alkaloids, then came flavonoids, phenols, and terpenes. MSHB and TTA SHB extracts exhibited minimal MTT cytotoxicity, with the lowest percentage inhibition recorded at 79.83 ± 7.66 % for MSHB at 500 µg/mL. Strong antioxidant activity was evident in both extracts, with IC 50 values less than those of ascorbic acid in DPPH radical scavenging assays. α-Glucosidase inhibition was demonstrated in the MSHB extract, while α-amylase inhibition was observed in the TTA SHB extract. The isolated pentacyclic triterpenes displayed low to moderate cytotoxicity, with IC 50 values ranging between 60.69 and 300.5 µg/mL. Moreover, all isolated triterpenes exhibited α-amylase and α-glucosidase inhibition, with alpha-amyrin acetate (SH-4) demonstrating notably higher α-glucosidase inhibition compared to the positive control, reaching 93.34 ± 0.52 % at 500 µM. The findings suggest that S. henningsii and its bioactive pentacyclic triterpenes possess promising attributes, including low cytotoxicity, potent antioxidant properties, and enzymatic inhibition, thereby potentially serving as valuable candidates for developing novel therapeutic interventions targeting type II diabetes. [ABSTRACT FROM AUTHOR]

• Sphagneticola trilobata taxonomy, phytochemistry & pharmacology were explored. • Taxonomy found multiple changes across Acmella, Wedelia & Sphagneticola genera. • Phytochemistry reveals rich terpenoid content especially diterpenoids in the plant. • Pharmacological reports show good wound healing, antioxidant & cytotoxic activity. • The plant's antivenom activity & its impact on fertility require more investigation. Sphagneticola trilobata , one of the ornamental creeping plants, belongs to family Asteraceae. This species has undergone several classification changes including, Compalaya, Acmella, Wedelia, and finally was officially classified as Sphagneticola in 1996. The plant holds significant importance in various traditional medicinal systems such as Ayurveda and Traditional Chinese Medicine for addressing a multitude of ailments. Therefore, excessive studies and research were performed to evaluate the phytochemical constituents and biological activities. Besides, the plant has been utilized recently in the green synthesis field, showing promising results. Hence, this paper aims to explore the taxonomy of Sphagneticola trilobata and provides comprehensive insights into its phytochemistry including terpenoids, sterols, phenolic compounds, and essential oil which were identified or isolated from different organs of the plant. Moreover, pharmacological properties were carefully examined. Specifically, it delves into its anti-inflammatory, antioxidant, wound healing, antimicrobial, and cytotoxic characteristics. Furthermore, the review will explore the plant's role in green synthesis, reflecting a contemporary global trend. Finally, we aim to identify critical knowledge gaps, paving the way for future scientific exploration. [ABSTRACT FROM AUTHOR]

In this study, we aimed to (i) better understand the phytochemical composition of extracts prepared from the leaves and roots with rhizomes of the scarcely studied Iris versicolor , and (ii) propose optimal extraction conditions (solvent composition, temperature, time) for the isolation of bioactive compounds. A UHPLC-QTOF-MS/MS targeted screening method was applied in combination with in silico fragmentation. The analysis revealed a total of 106 target metabolites, many of which are reported to occur in I. versicolor for the first time. (Iso)flavonoids were the most abundant compounds, followed by terpenoids, phenols, xanthones, phenolic acids, quinones, and steroids, with quinones being reported for the first time in this species. Terpenoids were characteristic of roots with rhizomes, while xanthones dominated in the leaves. Based on the varied experimental conditions, surface response analysis generated significant models for the extraction of terpenoids, quinones, and steroids. Our research provides valuable insight for the effective medicinal and commercial use of I. versicolor. [Display omitted] • A UHPLC-QTOF-MS/MS method was developed for metabolic screening of Iris versicolor. • 106 secondary metabolites detected, including phenolics and terpenoids. • Xanthones dominated in the leaves, while roots were rich in terpenoids. • Quinones reported to occur in I. versicolor for the first time. • Significant extraction models for terpenoids, steroids, and quinones. [ABSTRACT FROM AUTHOR]

As one of the most common tree species, birch wood (Betula pendula Roth) is widely used as a material of furniture and decoration indoors for its many excellent characteristics. Whereas there are some studies on the volatile composition of the essential oil from the leaves of Betula pendula Roth, only limited information is available on the odor-active constituents of birch wood. To close this gap, the odorants of birch wood were investigated by means of instrumental and sensory analyses, including techniques such as gas chromatography-flame ionization detection/olfactometry, high-resolution gas chromatography-mass spectrometry, and heart-cut two-dimensional high-resolution gas chromatography-mass spectrometry/olfactometry. Overall, a total of 20 odorants was (tentatively) identified on the basis of their respective odor qualities and retention indices and mass spectra by comparison with reference compounds. It was shown that birch wood odor is dominated by a series of terpenes, terpenoids and phenyl compounds originating from the degradation of lignin and aldehydes, ketones and acids originating from fatty acid degradation. By a sensory evaluation of the birch wood, the predominant odor attributes were determined to be earthy, pencil-like, corky/mouldy, grassy, fatty, fruity, green tea-like, herb-like, vanilla-like, and vinegar-like. [ABSTRACT FROM AUTHOR]

Terpenes are small hydrocarbon compounds that impart aroma and taste to many plants, including Cannabis sativa. A number of studies have shown that terpenes can produce pain relief in various pain states in both humans and animals. However, these studies were methodologically limited and few established mechanisms of action. In our previous work, we showed that the terpenes geraniol, linalool, β-pinene, α-humulene, and β-caryophyllene produced cannabimimetic behavioral effects via multiple receptor targets. We thus expanded this work to explore the potential antinociception and mechanism of these Cannabis terpenes in a mouse model of chronic pain. We first tested for antinociception by injecting terpenes (200 mg/kg, IP) into male and female CD-1 mice with mouse models of chemotherapy-induced peripheral neuropathy (CIPN) or lipopolysaccharide-induced inflammatory pain, finding that the terpenes produced roughly equal antinociception to 10 mg/kg morphine or 3.2 mg/kg WIN55,212. We further found that none of the terpenes produced reward as measured by conditioned place preference, while low doses of terpene (100 mg/kg) combined with morphine (3.2 mg/kg) produced enhanced antinociception vs either alone. We then used the adenosine A2A receptor (A2AR) selective antagonist istradefylline (3.2 mg/kg, IP) and spinal cord–specific CRISPR knockdown of the A2AR to identify this receptor as the mechanism for terpene antinociception in CIPN. In vitro cAMP and binding studies and in silico modeling studies further suggested that the terpenes act as A2AR agonists. Together these studies identify Cannabis terpenes as potential therapeutics for chronic neuropathic pain and identify a receptor mechanism for this activity. [ABSTRACT FROM AUTHOR]

The aroma of fine matured spirits is typically complex, resulting from numerous reactions occurring during the production process and some developing during maturation in oak casks. The refreshing sensation brought by mint notes was often expected, even after years of maturation. The main challenge lies in achieving an aromatic balance characterised by the seamless integration of woody aromas while maintaining the initial distillate's freshness. The present study examines the sensory effects associated with the interactions between wood, mint and cold sensations in spirits. Nine spirit model solutions were prepared, representing different combinations of terpene ketones (imparting mint aroma) and wood compounds, each at three concentration levels. The quantitative composition of mint compounds simulated varying degrees of mintiness in the distillate (low, medium and high), while the concentrations of wood compounds mimicked three maturation periods (short, intermediate and long term) in wooden casks. Samples were sensorily analysed by discriminative (triangle test) and rate‐all‐that‐apply (RATA) methodologies. An increase in woody intensity was notably perceived in samples with a low‐mint profile and containing wood compounds associated with medium and long‐term maturation. However, no significant sensory differences were observed in mint and cold perception between model solutions regardless of the simulated maturation conditions, indicating a limited influence of the studied wood compounds on the sensation of freshness in spirits due to competitive perceptual interactions with terpene ketones. [ABSTRACT FROM AUTHOR]

The flowers of selected Camellia yuhsienensis Hu specimens were studied at different stages of flowering to determine the volatile components of floral fragrance and how their concentrations changed during efflorescence. The mechanism of fragrance formation and release was also studied in order to provide a theoretical basis for the practical use of C. yuhsienensis Hu flowers. Headspace solid‐phase microextraction (HS‐SPME) was used to extract the natural floral volatile oils of C. yuhsienensis Hu at the different stages, and the floral fragrance components were analysed by gas chromatography–mass spectrometry (GC–MS). A total of 31, 59 and 55 compounds were detected at the budding, early‐blooming and full‐blooming stages respectively. These floral fragrance components included terpene alcohols, as well as other aromatic and aliphatic compounds, and the relative concentrations of the various compounds at different stages of flowering, were different, and those of fatty alcohols and terpene alcohols having higher relative contents at all stages. The main component at the budding stage of C. yuhsienensis Hu was ocimene, which has a grassy fragrance, accompanied by the scent of neroli oil, which gives it a refreshing, gentle and sweet, and explains why the floral fragrance of C. yuhsienensis Hu at the budding stage is extremely thin: the main component during the early‐blooming stage was 3‐carene. A higher percentage of 3‐carene increased the sweetness of the scent, manifesting the typical fragrant characteristics of C. yuhsienensis Hu. The main identified compound at the full‐blooming stage was α‐farnesene, which has a delicate fragrance, accompanied by a balsamic aroma, similar to the scent of gardenia, which is consistent with the sensory characteristics of C. yuhsienensis Hu. [ABSTRACT FROM AUTHOR]

Summary: Trichomes are specialized epidermal outgrowths covering the aerial parts of most terrestrial plants. There is a large species variability in occurrence of different types of trichomes such that the molecular regulatory mechanism underlying the formation and the biological function of trichomes in most plant species remain unexplored.Here, we used Chrysanthemum morifolium as a model plant to explore the regulatory network in trichome formation and terpenoid synthesis and unravel the physical and chemical roles of trichomes in constitutive defense against herbivore feeding.By analyzing the trichome‐related genes from transcriptome database of the trichomes‐removed leaves and intact leaves, we identified CmMYC2 to positively regulate both development of T‐shaped and glandular trichomes as well as the content of terpenoids stored in glandular trichomes. Furthermore, we found that the role of CmMYC2 in trichome formation and terpene synthesis was mediated by interaction with CmMYBML1. Our results reveal a sophisticated molecular mechanism wherein the CmMYC2–CmMYBML1 feedback inhibition loop regulates the formation of trichomes (non‐glandular and glandular) and terpene biosynthesis, collectively contributing to the enhanced resistance to Spodoptera litura larvae feeding.Our findings provide new insights into the novel regulatory network by which the plant synchronously regulates trichome density for the physical and chemical defense against herbivory. [ABSTRACT FROM AUTHOR]

Main conclusion: Temporal histolocalization of floral volatiles in the petal epidermis of Murraya paniculata was found to be linked with the coordinated expression of candidate genes and successive accumulation of an internal pool of volatiles. Murraya paniculata (Rutaceae) is known for its highly fragrant ephemeral flowers that emit volatiles to attract nocturnal pollinators. To unfold the patterns of volatile emission in relation to floral life-span, we studied time-course accumulation and emission rate of scent volatiles at six timepoints of floral maturation, at an interval of 4 h starting from the bud stage to the senescence stage on the next day. This study revealed the maximum emission rate of scent volatiles at the anthesis stage at 18:00 h. This finding correlates well with the maximum accumulation of volatiles in the internal pool of the flowers at this stage. The key volatiles detected in both emitted and internal pools were benzaldehyde, benzeneacetaldehyde, linalool, caryophyllene, germacrene-D and α-farnesene. In addition, the internal pool also contained substantial amounts of indole, scopoletin, caffeine and osthole. To histochemically localize the temporal accumulation of major volatile groups in the epidermal cells, petal cross sections were stained with NaDi and ferric chloride to visualize terpenes and phenolics, respectively, under light microscope. Histolocalization studies showed a higher accumulation of terpenes at 14:00 h and 18:00 h, which subsequently was reduced as senescence approached. Significant phenolics in the abaxial and adaxial layers of the petal epidermis accumulated at 18:00 h and at the early senescence (06:00 h) stages. Furthermore, temporal localization of active shikimate dehydrogenase (SKDH) protein through in-gel activity assay demonstrated higher enzymatic activities at anthesis (18:00 h) and fully bloomed (02:00 h) stages, supporting the findings of higher accumulation of phenolic volatiles at 18:00 h and 06:00 h stages. Expression analysis of major candidate genes of floral scent volatiles pathway supported the hypothesis that the emission rate of floral fragrance reached its maximum at the anthesis (18:00 h) stage. In contrast, biosynthesis of scent compounds started at the bud (14:00 h) stage itself as indicated by the RT–PCR semi-quantitative estimation. As flowers of M. paniculata attract multiple pollinator species, this study could also serve as a springboard for pollination biology in Rutaceae, which includes important fruit crops. [ABSTRACT FROM AUTHOR]

In this study, ginger slices were dehydrated through a combination of far-infrared radiation and hot-air drying (FIR-HAD). The changes in volatile composition were subsequently identified using gas chromatography-mass spectrometry (GC-MS) and metal oxide semiconductor electronic nose (MOS e-nose). The GC-MS analysis revealed that terpenes comprised over 75% of volatile compounds in all examined samples, with zingiberene, β-sesquiphellandrene, and (E, E)-α-farnesene being the dominant constituents. Fresh ginger contained a higher relative proportion compared to dried samples. After FIR-HAD treatment, the terpene levels decreased by 11.9%, 8.9%, 13.7%, and 18.2% at 50 °C, 60 °C, 70 °C, and 80 °C, respectively. Among the various drying conditions, ginger subjected to FIR-HAD at 60 °C displayed the highest concentrations of volatile compounds and exhibited flavor characteristics closest to those of fresh samples. The flavor profiles were further evaluated using MOS e-nose analysis. The terpene compounds demonstrated a strong correlation with the response values of W1W and W2W sensors according to partial least squares regression models. In addition, the concentrations of 6-gingerol, 8-gingerol, and 10-gingerol in ginger exposed to FIR-HAD at 60 °C were also higher compared to other drying conditions. This indicated that the FIR-HAD at 60 °C is more suitable for producing dried ginger with remaining flavor attributes. These findings offer theoretical insights into the changes in volatile compounds of ginger slices during the FIR-HAD procedure. They also highlight the potential for improving drying efficiency through aroma online control techniques in future research. [ABSTRACT FROM AUTHOR]

Melipona quadrifasciata quadrifasciata Lepeletier, 1836 (Mandaçaia) is a species of stingless bee, native in Brazil, that produces geopropolis, a physical mixture of propolis and clay, instead of producing conventional propolis. The present work aimed to chemically and thermally characterize Mandaçaia's geopropolis collected at Campo Alegre city, located in southern Brazil, and deepen the range of knowledge about its properties. The propolis extraction was carried out by hydroalcoholic maceration. Characterizations were performed using ultraviolet-visible spectrophotometry (UV-Vis), Fourier transformation infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), ultra-high performance liquid chromatography (UHPLC), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). UV-Vis results demonstrated a total polyphenol content of 10.15 ± 0.24 mg GAE.g−1 and total flavonoid content of 22.51 ± 3.47 mg QE.g−1. Chemical species from phenolic compounds such as terpenes, diterpenes, and fatty acids were identified by UHPLC. In conclusion, data showed that Mandaçaia's geopropolis extract has a rich and diverse chemical composition which encourages new studies about its pharmaceutical, cosmetic, and food applications. [ABSTRACT FROM AUTHOR]

The Yamaguchi reagent, based on 2,4,6-trichlorobenzoyl chloride (TCBC) and 4-dimethylaminopyridine (DMAP), is an efficient tool for conducting the intermolecular (esterification) reaction between an acid and an alcohol in the presence of a suitable base (Et3N or iPr2NEt) and solvent (THF, DCM, or toluene). The Yamaguchi protocol is renowned for its ability to efficiently produce a diverse array of functionalized esters, promoting high yields, regioselectivity, and easy handling under mild conditions with short reaction times. Here, the recent utilization of the Yamaguchi reagent was reviewed in the synthesis of various natural products such as macrolides, terpenoids, polyketides, peptides, and metabolites. [ABSTRACT FROM AUTHOR]

Evolutionary dynamics of inversion and its impact on biochemical traits are a puzzling question. Here, we show abundance of inversions in three Curcuma species (turmeric, hidden ginger and Siam tulip). Genes within inversions display higher long terminal repeat content and lower expression level compared with genomic background, suggesting inversions in Curcuma experience relaxed genetic constraints. It is corroborated by depletion of selected SNPs and enrichment of deleterious mutations in inversions detected among 56 Siam tulip cultivars. Functional verification of tandem duplicated terpene synthase (TPS) genes reveals that genes within inversions become pseudogenes, while genes outside retain catalytic function. Our findings suggest that inversions act as a counteracting force against tandem duplication in balancing birth and death of TPS genes and modulating terpenoid contents in Curcuma. This study provides an empirical example that inversions are likely not adaptive but affect biochemical traits. Evolutionary dynamics of inversions and their impact on biochemical traits are unclear. Here, the authors report the genome assemblies of three Curcuma species and find that terpene synthase genes quite often become pseudogenes inside an inversion, indicating inversions act as a counteracting force against gene tandem duplication. [ABSTRACT FROM AUTHOR]

Background: Geranyllinalool, a natural diterpenoid found in plants, has a floral and woody aroma, making it valuable in flavors and fragrances. Currently, its synthesis primarily depends on chemical methods, which are environmentally harmful and economically unsustainable. Microbial synthesis through metabolic engineering has shown potential for producing geranyllinalool. However, achieving efficient synthesis remains challenging owing to the limited availability of terpenoid precursors in microorganisms. Thus, an artificial isopentenol utilization pathway (IUP) was constructed and introduced in Escherichia coli to enhance precursor availability and further improve terpenoid synthesis. Results: We first constructed an artificial IUP in E. coli to enhance the supply of precursor geranylgeranyl diphosphate (GGPP) and then screened geranyllinalool synthases from plants to achieve efficient synthesis of geranyllinalool (274.78 ± 2.48 mg/L). To further improve geranyllinalool synthesis, we optimized various cultivation factors, including carbon source, IPTG concentration, and prenol addition and obtained 447.51 ± 6.92 mg/L of geranyllinalool after 72 h of shaken flask fermentation. Moreover, a scaled-up production in a 5-L fermenter was investigated to give 2.06 g/L of geranyllinalool through fed-batch fermentation. To the best of our knowledge, this is the highest reported titer so far. Conclusions: Efficient synthesis of geranyllinalool in E. coli can be achieved through a two-step pathway and optimization of culture conditions. The findings of this study provide valuable insights into the production of other terpenoids in E. coli. [ABSTRACT FROM AUTHOR]

Chlororaphens A and B are structurally unique non‐canonical C17 sesquiterpenoids from Pseudomonas chlororaphis that are made by two SAM‐dependent methyltransferases and a type I terpene synthase. This study addresses the mechanism of their formation in isotopic labelling experiments and DFT calculations. The results demonstrate an astonishing complexity with distribution of labellings within a cyclopentane core that is reversely connected to two acyclic fragments in chlororaphen A and B. In addition, the uptake of up to 14 deuterium atoms from D2O was observed. These findings are explainable by a repeated late stage multistep rearrangement sequence. The absolute configurations of the chlororaphens and their biosynthetic intermediates were elucidated in stereoselective labelling experiments. [ABSTRACT FROM AUTHOR]

Background: Solid tumors often develop hypoxic regions, leading to aggressive behavior and increased drug resistance. Methods: The chemical composition of Cymbopogon citratus essential oil (EO) was analyzed using GC-MS. Alginate nanoparticles containing the EO and its primary component, citral, were synthesized via the ionic gelation method. Encapsulation was confirmed using ATR-FTIR analysis. The anticancer efficacy of C. citratus EO, citral, and their respective alginate nanoparticles was evaluated under normoxic (21% oxygen) and hypoxic (1% oxygen) conditions on breast cancer (MDA-MB-231) and melanoma (A-375) cell lines. Additionally, qPCR and flow cytometry were used to assess apoptosis gene expression ratios (Bax/Bcl-2) and levels of apoptosis. Results: Citral (80.98%) was identified as the major component of the EO. Alginate nanoparticles containing C. citratus EO and citral (C. citratus-AlgNPs and citral-AlgNPs) were synthesized with particle sizes of 195 ± 4 nm and 222 ± 9 nm, and zeta potentials of -22 ± 3 mV and − 17 ± 1 mV, respectively. Both samples demonstrated significantly greater efficacy under hypoxic conditions. Citral and C. citratus-AlgNPs had IC50 values of 27 (19–39) µg/mL and 25 (4-147) µg/mL, respectively, against MDA-MB-231 and A-375 cells. Flow cytometry showed increased apoptosis under hypoxic conditions, with the highest rates observed for citral-AlgNPs and C. citratus-AlgNPs (84 ± 5 and 92 ± 5% in MDA-MB-231 and A-375 cells, respectively). Conclusion: This study demonstrates that alginate nanoparticles enhance the anticancer activity of C. citratus-AlgNPs and citral, particularly under hypoxic conditions, highlighting their potential for hypoxia-targeted cancer therapies. [ABSTRACT FROM AUTHOR]

SUMMARY: Presilphiperfolane‐type sesquiterpenes represent a unique group of atypical sesquiterpenoids characterized by their distinctive tricyclic structure. They have significant potential as lead compounds for pharmaceutical and agrochemical development. Herein, we utilized a transcriptomic approach to identify a terpene synthase (TPS) gene responsible for the biosynthesis of rare presilphiperfolane‐type sesquiterpenes in Inula lineariifolia, designated as IlTPS1. Through phylogenetic analysis, we have identified the evolutionary conservation of key motifs, including RR(x)8W, DDxxD, and NSE/DTE in IlTPS1, which are shared with other tricyclic sesquiterpene synthases in the TPS‐a subfamily of Asteraceae plants. Subsequent biochemical characterization of recombinant IlTPS1 revealed it to be a multiproduct enzyme responsible for the synthesis of various tricyclic sesquiterpene alcohols from farnesyl diphosphate (FPP), resulting in production of seven distinct sesquiterpenes. Mass spectrometry and nuclear magnetic resonance (NMR) spectrometry identified presilphiperfolan‐8β‐ol and presilphiperfol‐7‐ene as predominant products. Furthermore, biological activity assays revealed that the products from IlTPS1 exhibited a potent antifungal activity against Nigrospora oryzae. Our study represents a significant advancement as it not only functionally identifies the first step enzyme in presilphiperfolane biosynthesis but also establishes the heterologous bioproduction of these unique sesquiterpenes. Significance Statement: Our research has uncovered the molecular mechanism responsible for the synthesis of rare, bridged tricyclic sesquiterpenes by IlTPS1. Furthermore, we have established their bioproduction and assessed their antimicrobial properties. This study serves as a promising example of how unique sesquiterpene natural products can be harnessed and leveraged in the pharmaceutical and agrochemical sectors for various applications. [ABSTRACT FROM AUTHOR]

The deprotonation–reprotonation sequence introduces additional cyclization branches in terpene biosynthesis. However, the underlying mechanism remains poorly understood. In this study, we employed a combined approach of molecular dynamics (MD) simulations and site-directed mutagenesis on astellifadiene synthase EvAS from Emericella variecolor to investigate the role of a protonated S85 residue. This residue acts as a catalytic acid, previously unreported, that facilitates the reprotonation step in astellifadiene biosynthesis. Mutating S85 led to the production of a new tricyclic sesterterpene. [ABSTRACT FROM AUTHOR]

Summary: Stomatal closure during drought inhibits carbon uptake and may reduce a tree's defensive capacity. Limited carbon availability during drought may increase a tree's mortality risk, particularly if drought constrains trees' capacity to rapidly produce defenses during biotic attack.We parameterized a new model of conifer defense using physiological data on carbon reserves and chemical defenses before and after a simulated bark beetle attack in mature Pinus edulis under experimental drought. Attack was simulated using inoculations with a consistent bluestain fungus (Ophiostoma sp.) of Ips confusus, the main bark beetle colonizing this tree, to induce a defensive response.Trees with more carbon reserves produced more defenses but measured phloem carbon reserves only accounted for c. 23% of the induced defensive response. Our model predicted universal mortality if local reserves alone supported defense production, suggesting substantial remobilization and transport of stored resin or carbon reserves to the inoculation site.Our results show that de novo terpene synthesis represents only a fraction of the total measured phloem terpenes in P. edulis following fungal inoculation. Without direct attribution of phloem terpene concentrations to available carbon, many studies may be overestimating the scale and importance of de novo terpene synthesis in a tree's induced defense response. [ABSTRACT FROM AUTHOR]

Background: Achieving cost-competitiveness remains challenging for industrial biomanufacturing. With whole-cell biocatalysis, inefficiency presents when individual cells vary in their production levels. The problem exacerbates when the basis for such production heterogeneity is heritable. Here, evolution selects for the low- and non-producers, as they have lowered/abolished the cost of bioproduction to fitness. With the scale of population expansion required for industrial bioproduction, the asymmetrical enrichment can be severe enough to compromise the performance, and hence commercial viability of the bioprocess. Clearly, addressing production heterogeneity is crucial, especially in improving the stability of bioproduction across the cell generations. In this respect, we designed a growth-coupling strategy for terpenoid bioproduction in Escherichia coli. By knocking out the native 1-deoxy-D-xylulose 5-phosphate reductoisomerase (dxr) gene and introducing the heterologous mevalonate pathway, we created a chassis that relies solely on the latter for synthesis of all terpenoids. We hypothesise that the need to sustain the biosynthesis of endogenous life-sustaining terpenoids will impose a minimum level of productivity, which concomitantly improves the bioproduction of our target terpenoid. Results: Following the confirmation of lethality of a dxr knockout, we challenged the strains with a continuous plasmid-based bioproduction of linalool. The Δdxr strain achieved an improved productivity profile in the first three days post-inoculation when compared to the parental strain. Productivity of the Δdxr strain remained observable near the end of 12 days, and after a disruption in nutrient and oxygen supply in a separate run. Unlike the parental strain, the Δdxr strain did not evolve the same deleterious mutations in the mevalonate pathway, nor a viable subgroup that had lost its resistance to the antibiotic selection pressure (a plausible plasmid loss event). We believe that this divergence in the evolution trajectories is indicative of a successful growth-coupling. Conclusion: We have demonstrated a proof of concept of a growth-coupling strategy that improves the performance, and stability of terpenoid bioproduction across cell generations. The strategy is relatively broad in scope, and easy to implement in the background as a 'fail-safe' against a fall in productivity below the imposed minimum. We thus believe this work will find widespread utility in our collective effort towards industrial bioproduction. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

High-pressure processing (HPP) is a promising technology for increasing the shelf life of food, with minimal effects on the nutritional or sensory quality. However, there has been a concern that high-oil-content foods may protect food pathogens in HPP, and that HPP can affect the quality of lipids. We inoculated Listeria monocytogenes and Salmonella Typhimurium into 34% and 54% oil-content pesto sauce, processed them either with HPP (600 MPa, 4 min) or thermal processing (82 °C, 5 min), and analyzed bacteria counts, pH, GC-MS (Terpene compounds), the time–kill kinetic study, and lipid oxidation value for 60 days in refrigerating storage (5 ± 2 °C). Our findings show that HPP significantly reduced the number of bacteria (more than 4-log) compared to thermal processing or non-processing. Additionally, we discovered terpene compounds (highest-level terpene: L-linalool, eugenol, and 1,8-cineol) in pesto oil that exhibit antimicrobial activity. Different oil content did not have any significant effect on bacteria levels. Regarding chemical results, all samples were of acceptable quality, and the processes did not show any negative effect on lipid oxidation (Peroxide and P-Anisidine value under 10 meq per kilogram of oil). In conclusion, our study indicates that HPP is a suitable method for high-oil-content pesto sauce. In addition, functional compounds naturally present in pesto may contribute to maintaining its microbial and chemical quality. [ABSTRACT FROM AUTHOR]

α-Pinene (PEN) is a phyto compound present in terpene plants. In traditional medicine, PEN has been used for its anti-inflammatory, pain-relieving, and bronchodilator properties. The effect of PEN in combination with temozolomide (TMZ) in glioblastoma multiforme (GBM) cells has been evaluated. The action of the PEN + TMZ combination on cell migration, soft-agar, and cell death was determined in LN229 and U87MG human glioblastoma cells. In combination, PEN with TMZ showed a synergistic inhibitory effect in the GBM cells. The PEN + TMZ treatment showed a higher fluorescent intensity and reduced the percentage of wound area closure compared to the compound alone. The compounds in combination also resulted in a reduction in single-cell colony formation. To conclude, the study showed that plant-derived PEN enhanced the effectiveness of standard chemotherapeutic, TMZ, in LN229 and U87MG cells. [ABSTRACT FROM AUTHOR]

Nitrogen is critical for rice yield and quality, but its overuse can be detrimental to efficiency and the environment. To identify changes in the quality of rice in response to the reduced application of nitrogen fertilizer, we carried out a comprehensive metabolomics study of SuiJing 18 using volatile metabolomics methods. Our results showed that SuiJing 18 had a total of 358 volatile metabolites, mainly lipids (16.25%), terpenoids (15.41%), heterocyclic compounds (15.13%), and hydrocarbons (13.45%). SuiJing 18 underwent significant changes in response to the reduced application of nitrogen fertilizer. Key sweet volatile compounds such as 4-methyl-benzeneacetaldehyde, hexyl acetate, and 2-methylnaphthalene were present at significantly higher levels when nitrogen fertilizer was applied at a rate of 68 kg of pure nitrogen per hectare, and their flavor characteristics also differed significantly from the compounds resulting from the other two treatments. Focusing on 16 differential volatile metabolites, we further investigated their effects on flavor and quality, thus laying the foundation for a greater understanding of the biomarkers associated with changes in rice quality. This study contributes to a better understanding of the mechanisms underlying changes in rice quality after reduced nitrogen fertilizer application. [ABSTRACT FROM AUTHOR]

The control over the movement of electrons during chemical reactions with oriented external electric fields (OEEFs) has been predicted to offer a general approach to catalysis. Recently, we suggested that many problems to realize electric‐field catalysis in practice under scalable bulk conditions could possibly be solved on multiwalled carbon nanotubes in electromicrofluidic reactors. Here, we selected monoterpene cyclizations to assess the scope of our system in organic synthesis. We report that electric‐field catalysis can function by stabilizing both anionic and cationic transition states, depending on the orientation of the applied field. Moreover, electric‐field catalysis can promote reactions which are barely accessible by general Brønsted and Lewis acids and field‐free anion‐π and cation‐π interactions, and drive chemoselectivity toward intrinsically disfavored products without the need for pyrene interfacers attached to the substrate to prolong binding to the carbon nanotubes. Finally, interfacing with chiral organocatalysts is explored and evidence against contributions from redox chemistry is provided. [ABSTRACT FROM AUTHOR]

Aim: Environmental exposure constitutes a significant determinant in the pathogenesis of metabolic syndrome (MetS). Nevertheless, the contribution of environmental factors to MetS remains ambiguous. The present study was aimed at investigating the correlation between serum terpenes and the risk of MetS in the general population. Methods: A cross‐sectional study was conducted among 1266 individuals from the 2013–2014 National Health and Nutrition Examination Survey (NHANES). Serum terpenes and MetS risk were analyzed using a weighted logistic regression model. Weighted quantile sum (WQS) regression was utilized to explore the relationship between the mixture of serum terpenes and MetS. The restricted cubic spline (RCS) method was employed to assess the dose–response relationship between them. All data and analyses were conducted using the "Survey" package in R software (Version 4.3.2). Results: The study population, with an average age of 46.82 ± 0.46 years and a body mass index (BMI) of 28.97 kg/m2, consisted of 48.15% males and 67.99% Whites. Among the participants, 35.78% were diagnosed with MetS. The weighted logistic regression showed that tertiles of serum levels of α‐pinene, β‐pinene, and limonene were positively correlated with MetS risk with a OR value of 1.90 (1.14, 3.16), 2.02 (1.23, 3.31), and 2.35 (1.33, 4.13) and elevated triglycerides (TGs) with a OR of 2.36 (1.63, 3.43), 3.51 (2.30, 5.38), and 3.96 (2.55, 6.15) (all ptrend < 0.05). The WQS regression indicated a positive association between serum terpene mixture and MetS risk (OR = 1.65, 95% CI: 1.18–2.3), increased TG (OR = 2.69, 95% CI: 1.94–3.71), and reduced high‐density lipoprotein cholesterol (HDL‐C) (OR = 1.46, 95% CI: 1.03–2.07) (all ptrend < 0.01). The RCS analysis further supported the dose–response relationship. Conclusion: This study suggested potential adverse effects of terpene exposure on human health, emphasizing the importance of environmental interventions in maintaining health. [ABSTRACT FROM AUTHOR]

Essential oil (EO) allelopathy has been considered as potential applications in organic agriculture and weed management, where the EOs can be used as eco-friendly natural herbicides. Rhazya stricta is a widely distributed dwarf shrub in the Arabian Peninsula and is characterized by its toxicity. The present study aimed to investigate the chemical composition of the R. stricta EO using quantitative and qualitative analysis via Gas chromatography/ mass spectroscopy (GC-MS) and GC-flame ionization detection (GC-FID) as well as assess its phytotoxicity on weeds. Fifty-four volatile components were identified, representing 97.5% of total oil. The terpenes were found as the backbone of the oil constituents including mono- (55.28%) and sesqui-terpenes (27.35%), alongside non-terpenoid constituents (13.63%). From the overall identified oil constituents, trans-chrysanthenyl acetate (31.57%), cis-verbenol (11.84%), octadecenoic acid, methyl ester (4.84%), cubenol (4.82%), davana ether (4.79%), (E)-9-octadecenoic acid ethyl ester (3.93%) represented the abundant compounds. The EO exhibited strong phytotoxicity on the germination and seedling growth of weeds Dactyloctenium aegyptium and Chenopodiastrum murale compared to the crop Triticum aestivum. The EO showed an IC50 of 6.66, 7.75, and 6.45 mg/L for seed germination, shoot growth, and root growth, respectively for the weed D. aegyptium, while it showed 5.41, 8.33, and 6.82 mg/L for C. murale compared to 16.9, 18.5, and 19.5 for T. aestivum mg/L for seed germination, shoot growth, and root growth, respectively. The observed strong phytotoxicity could be ascribed to the higher content of the oxygenated terpenoid compounds, whereas, further study is recommended to evaluate the phytotoxicity of the major compounds either singularly or in combination against weeds and determine their mode(s) of action as bioherbicides. [ABSTRACT FROM AUTHOR]

Citri Exocarpium Rubrum black tea (CER tea) is a novel blend tea infusion combining tea and CER. Due to its potential health benefits and unique flavor, it has gained popularity among consumers. Nevertheless, the aroma characteristics and key odorants of it remain to be distinguished and cognized. The HS‐SPME and GC/MS techniques were employed to analyze the alterations in volatile constituents throughout the critical stages of CER tea production. A total of 200 chemical compounds exhibited notable disparities during the processing procedures. Among them, terpenes and esters were the most abundant compounds in CER tea, which might be the key material basis for the aroma quality of CER tea. It is worth noting that 124 metabolites were significantly increased in the kneading stage and drying stage, including benzeneacet aldehyde, trans‐nerolidol, and D‐limonene, with contained floral and fruity odors, which might be closely related to the aroma of CER tea. Monoterpenes might be important contributors to the aroma of CER tea. This study provided a theoretical basis for the quality improvement of CER tea. [ABSTRACT FROM AUTHOR]

Geosmin and 2‐methylisoborneol (MIB) are known to cause taste‐and‐odour problems in recirculating aquaculture systems (RAS). Both geosmin and MIB are microbial metabolites belonging to terpenoids. Precursors for terpenoids are biosynthesized via the methylerythritol phosphate (MEP) and the mevalonate (MVA) pathways. We carried out a metagenomic analysis of 50 samples from five RAS to investigate terpenoid biosynthesis and metabolic potential for geosmin and MIB production in RAS microbiomes. A total of 1008 metagenome‐assembled genomes (MAGs) representing 26 bacterial and three archaeal phyla were recovered. Although most archaea are thought to use the MVA pathway for terpenoid precursor biosynthesis, an Iainarchaeota archaeal MAG is shown to harbour a complete set of genes encoding the MEP pathway but lacking genes associated with the MVA pathway. In this study, a total of 16 MAGs affiliated with five bacterial phyla (Acidobacteriota, Actinobacteriota, Bacteroidota, Chloroflexota, and Myxococcota) were identified as possessing potential geosmin or MIB synthases. These putative taste and odour producers were diverse, many were taxonomically unidentified at the genus or species level, and their relative abundance differed between the investigated RAS farms. The metagenomic study of the RAS microbiomes revealed a previously unknown phylogenetic diversity of the potential to produce geosmin and MIB. [ABSTRACT FROM AUTHOR]

Coniferous trees produce secondary or defense chemicals, such as terpenes, against pest insects. Terpenes could serve as constitutive or induced defensive mechanisms, defending the tree from invasive herbivores. The Mediterranean pine shoot beetle Tomicus destruens colonizes stems and branches of Pinus brutia trees and even can kill mature trees during periodic outbreaks. We investigated whether terpene profiles of needle and stem of P. brutia trees differ between health and those infested by T. destruens. We selected 20 healthy and T. destruens-infested trees and analyzed the monoterpenes and sesquiterpenes of their needles and phloem. We found higher concentrations of tricyclene, camphene and p-cymene in the phloem of infested trees. Similarly, the needles of infested trees had higher concentrations of α-pinene, β-pinene, myrcene, limonene, trans-β-caryophyllene and α-humulene than healthy trees. These results show that the monoterpene and sesquiterpene profiles of P. brutia trees differed between healthy and infested trees, suggesting that volatile terpenes may be an important part of plant-induced responses against T. destruens. [ABSTRACT FROM AUTHOR]

The root of Paeonia lactiflora pall. is a significant component of traditional Chinese medicine, with terpenoids and their glycosides, such as paeoniflorins, serving as key active ingredients known for their anti-inflammatory, hepatoprotective, and analgesic properties. By generating a transcriptome and functionally characterizing 32 terpene synthases (TPSs) from P. lactiflora, we successfully constructed 24 pESC-Trp-PlTPS expression vectors. Through expression in Saccharomyces cerevisiae engineered strains, we identified four mono-TPSs and five sesqui-TPSs that produce 18 compounds, including eight monoterpenes and ten sesquiterpenes in vitro. This includes a bifunctional enzyme (PlTPS22). Additionally, PlTPS21 was characterized as a pinene synthase with α-pinene as its main product. The expression pattern of PlTPS21 aligns closely with the accumulation patterns of paeoniflorins and α-pinene in the plant, suggesting that PlTPS21 is a key enzyme in the biosynthesis of paeoniflorin. [ABSTRACT FROM AUTHOR]

The unimolecular reactions of protonated myrcene and linalool were investigated by collision‐induced dissociation and density functional theory calculations. Experiments on a triple quadrupole mass spectrometer showed that protonated myrcene undergoes two major unimolecular reactions losing propene and isobutene, and two minor reactions of ethene and propane loss. In each case, the product ion consists of a substituted five‐member ring. Protonation of myrcene was found to form four distinct protomers, three of which can be significantly populated in the ion source. The observed fragmentation reactions were calculated and found to depend on the starting protomer. Each pathway consisted of several hydrogen‐migration and ring‐forming/opening steps on the way to the observed products. Likewise, protonation of linalool also produces three distinct protomers, with the global minimum being formed by protonation of a central double bond. The major reaction is water loss to form protonated myrcene, but two minor channels were also observed resulting in loss of acetone and isobutene. The calculated minimum energy reaction pathways were found to be consistent with the relative abundances of the ions in the experimental breakdown diagrams. [ABSTRACT FROM AUTHOR]

This study employs a high‐dimensional consensus mass spectral (HDCMS) similarity scoring technique to discriminate isomers collected using an electron ionization mass spectrometer. The HDCMS method was previously introduced and applied to the discrimination of mass spectra of constitutional isomers, methamphetamine and phentermine, collected with direct analysis real‐time mass spectrometry (DART‐MS). The method formulates the problem of discriminating mass spectra in a mathematical Hilbert space and is hence called "high dimensional." It requires replicate mass spectra to build a Gaussian model and evaluate the inner products between these functions. The resulting measurement variability is used as a signature by which to discriminate spectra. In this work, HDCMS is tested on electron impact ionization (EI) mass spectra of 7 terpene and terpene‐related (C10H16 and C10H14) isomers with experimental retention indices that differ by less than 30 and with traditional cosine similarity scores greater than 0.9, on a scale of 0 to 1, when compared with at least one other compound in the test set. Using identical instrument parameters, 15 replicate gas chromatography–electron ionization–mass spectrometry (GC‐EI‐MS) spectra of each isomer were collected and separated into distinct library and query sets. The HDCMS algorithm discriminated each isomer, indicating the method's potential. Because the method requires replicate measurements, observations from a simple heuristic study of the number of replicates required to discriminate these isomers is presented. The paper concludes with a discussion of compound discrimination using HDCMS and the benefits and drawbacks of applying the method to EI‐MS data. [ABSTRACT FROM AUTHOR]