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opennotspecifiedDec 2011View details →

Figure 2. Selected 1H-1H in Schizanthines N, O, and P, Tropane Alkaloids from the Aerial Parts ofSchizanthus tricolor

Figure 2. Selected 1H-1H COSY (dashed arrows) and 1H-13C HMBC (full arrows) correlations observed for compounds 1, 2, and 3.

opencc-zeroSep 2019View details →

Data from: Selection on tropane alkaloids in native and non-native populations of Datura stramonium

Theories of plant invasion based on enemy release in a new range assume that selection exerted by specialist herbivores on defence traits should be reduced, absent, or even selected against in the new environment. Here, we measured phenotypic selection on atropine and scopolamine concentration of Datura stramonium in eight native (Mexico) and 14 non-native (Spain) populations. Native populations produced between 20 and 40 times more alkaloid than non-native populations (atropine: 2.0171 vs. 0.0458 mg/g; scopolamine: 1.004 vs. 0.0488 mg/g, respectively). Selection on alkaloids was negative for atropine and positive for scopolamine concentration in both ranges. However, the effect sizes of selection gradients were only significant in the native range. Our results support the assumption that the reduction of plant defence in the absence of the plant's natural enemies in invasive ranges is driven by natural selection.

opencc-zeroDec 2016View details →

Data from: Widespread chemical detoxification of alkaloid venom by formicine ants

The ability to detoxify defensive compounds of competitors provides key ecological advantages that can influence community-level processes. Although common in plants and bacteria, this type of detoxification interaction is extremely rare in animals. Here, using laboratory behavioral assays and analyses of videotaped interactions in South America, we report widespread venom detoxification among ants in the subfamily Formicinae. Across both data sets, nine formicine species, representing all major clades, used a stereotyped grooming behavior to self-apply formic acid (acidopore grooming) in response to fire ant (Solenopsis invicta and S. saevissima) venom exposure. In laboratory assays, this behavior increased the survivorship of species following exposure to S. invicta venom. Species expressed the behavior when exposed to additional alkaloid venoms, including both compositionally similar piperidine venom of an additional fire ant species and the pyrrolidine/pyrroline alkaloid venom of a Monomorium species. In addition, species expressed the behavior following exposure to the uncharacterized venom of a Crematogaster species. However, species did not express acidopore grooming when confronted with protein-based ant venoms or when exposed to monoterpenoid-based venom. This pattern, combined with the specific chemistry of the reaction of formic acid with venom alkaloids, indicates that alkaloid venoms are targets of detoxification grooming. Solenopsis thief ants, and Monomorium species stand out as brood-predators of formicine ants that produce piperidine, pyrrolidine, and pyrroline venom, providing an important ecological context for the use of detoxification behavior. Detoxification behavior also represents a mechanism that can influence the order of assemblage dominance hierarchies surrounding food competition. Thus, this behavior likely influences ant-assemblages through a variety of ecological pathways.

Fig. 1 in Phytochemical genomics of the Madagascar periwinkle: Unravelling the last twists of the alkaloid engine

Fig. 1. Overview of the MIA biosynthetic pathway highlighting the preferential distribution of MIAs within Catharanthus roseus.

Fig. 2 in Phytochemical genomics of the Madagascar periwinkle: Unravelling the last twists of the alkaloid engine

Fig. 2. Model for the alkaloid plant cell factories in Catharanthus roseus leaves. The biosynthesis of MIAs sequentially involves internal phloem associated parenchyma (IPAP) cells, pavimentous epidermal cells (upper and lower) and specialized cells (laticifers and idioblasts). The biosynthetic pathway leading to vindoline is shown in the margins of the leaf diagram. Known single enzymatic steps in each cell type are indicated by grey arrows and abbreviation of enzyme names. Broken grey arrows indicate unknown enzymatic steps. No specific cellular localization for NMT has been determined. A DNA helix is shown besides proteins encoded by genes characterized by exploiting C. roseus transcriptomic resources. In the leaf diagram, dashed arrows indicate conversion of pyruvate (A) and GAP (B) to loganic acid (C) in IPAP cells; conversion of loganic acid (C) to 16-methoxy-tabersonine (D) in epidermis (for simplification, only the conversion in the upper epidermis is shown) and conversion of desacetoxyvindoline (E) to vindoline (F) in laticifers and idioblasts. The blue arrows indicate intercellular metabolite translocation for loganic acid (C) and secretion to the leaf surface for catharantine. Broken blue arrows indicate that the translocated metabolite is uncharacterized/unknown. DXS, 1-deoxy-D-xylulose-5-phosphate (DXP) synthase; DXR, DXP reductoisomerase; CMS, 4- (cytidine 50-diphospho)-2C-methyl-D-erythritol (CM) synthase; CMK, CM kinase; MECS, 2C-methyl-D-erythritol-2,4-cyclodiphosphate (MEC) synthase; HDS, hydroxymethylbutenyl 4-diphosphate (HD) synthase; HDR, HD reductase; IDI, isopentenyl diphosphate isomerase; GPPS, geranyl diphosphate synthase; GES, geraniol synthase; G10H (CYP76B6), geraniol 10-hydroxylase; CPR, cytochrome P450-reductase; 10HGO, 10-hydroxygeraniol oxidoreductase; IS, iridoid synthase; 7DLGT, 7-deoxyloganetic acid glucosyltransferase; 7DLH, 7-deoxyloganic acid hydroxylase; LAMT, loganic acid O-methyltransferase; SLS (CYP72A1), secologanin synthase; TDC, tryptophan decarboxylase; STR, strictosidine synthase; SGD, strictosidine b-glucosidase; T16H2 (CYP71D351), tabersonine 16-hydroxylase 2; 16OMT, 16-hydroxytabersonine O-methyltransferase; TPT2, catharanthine transporter from pleiotropic drug resistance (PDR) family of ABC transporters; D4H, desacetoxyvindoline 4-hydroxylase; DAT, deacetylvindoline 4-Oacetyltransferase. DMAPP, dimethylallyl diphosphate; GAP, glyceraldehyde 3-phosphate; IPP, isopentenyl diphosphate. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 4 in Phytochemical genomics of the Madagascar periwinkle: Unravelling the last twists of the alkaloid engine

Fig. 4. Virus-induced gene silencing monitored in C. roseus by targeting phytoene desaturase (PDS). (A) Control plant. (B) Photobleaching phenoptype of upper leaves as a marker of PDS silenced tissues in plant co-infiltrated with Agrobacterium tumefaciens strain GV3101 containing pTRV1 and pTRV2-PDS (T-DNA vectors carrying, respectively RNA1 and RNA2 TRV genome) (S. Besseau and V. Courdavault, personal data). Seedlings were grown at 28 °C and transferred at 21 °C after transformation to improve VIGS efficiency as suggested by Sung et al. (2014).

Fig. 3 in Phytochemical genomics of the Madagascar periwinkle: Unravelling the last twists of the alkaloid engine

Fig. 3. The use of high-throughput transcriptomic data for discovery of MIA biosynthetic genes. Two non-exclusive strategies may be used: orthology comparison with other species (left panel) and clustering of gene expression (right panel). The former approach requires transcriptomic data from candidate species with specific alkaloid metabolisms (e.g. secologanin (11)-producing (purple inset) and non secologanin (11)-producing (blue inset) species). Such data are available from the MPGR and PhytoMetaSyn projects. A first orthology comparison using the OrthoMCL algorithm (Li et al., 2003) could help identify conserved genes encoding enzymes involved in the biosynthesis of common precursors in MIA-producing species (Camptotheca acuminata, Rauwolfia serpentina, C. roseus) but also specific enzymatic activities dedicated to the synthesis of particular alkaloids, such as the C. roseus specific genes. A second orthology analysis can be further performed on the set of conserved genes found in the MIAproducing species to isolate candidates from the secoiridoid pathway by comparing with transcriptomic data from non secologanin (11)-producing enzymes. The second strategy relies on transcriptome analyses from diverse experimental conditions to construct a reference transcriptome which will be used to estimate the abundance of each transcript in each condition in order to cluster genes according to their expression levels. The more experimental conditions are available, the more the clustering analysis will be efficient to group co-regulated genes. Note that this reference transcriptome could also serve to the orthology analysis depicted in the left panel, and also to verify expression levels of candidate genes resulting from this kind of approach. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

opencc-zeroNov 2021View details →

Interactions between silicon and alkaloid defences in endophyte-infected grasses and the consequences for a folivore

1. Grasses have developed a wide range of morphological and physiological mechanisms to resist herbivory. For instance, they accumulate silicon (Si) in tissue, as physical defence, and associate symbiotically with foliar Epichloë-endophytes that provide chemical defence via antiherbivore alkaloids. Recent evidence showed that some Epichloë-endophytes increase foliar Si in forage grasses; however, it is unknown whether this impacts insect herbivores. Furthermore, while Si is primarily a physical defence, it also affects production of plant defensive secondary metabolites; Si supply might therefore affect Epichloë-alkaloids, although this remains untested. 2. We grew endophyte-free (Nil) and Epichloë-infected tall fescue and perennial ryegrass in a factorial combination with or without Si supplementation, in the absence or presence of Helicoverpa armigera. Epichloë-endophyte strains were AR584 for tall fescue, and AR37, AR1 or Wild-type (WT) for perennial ryegrass. We assessed how Si supply and Epichloë-endophytes in interaction with herbivory affected foliar Si and mutualist-derived alkaloid concentrations. Subsequently, their effects on H. armigera relative growth rates (RGR) were evaluated. 3. Endophytes generally increased Si concentrations in Si supplied plants. In tall fescue-AR584 and perennial ryegrass-AR37, endophytes increased constitutive (herbivore-free) and induced (herbivore-inoculated) Si concentrations by at least 25%; in contrast, in perennial ryegrass the AR1 endophyte only increased constitutive levels. Si supply did not affect alkaloids produced by AR584- or AR1/WT-endophytes; however, in the presence of herbivory, Si supply decreased the induction of alkaloids produced by AR37 endophytes by 33%. For tall fescue, Si supply reduced H. armigera RGR by at least 76%, regardless of endophytic status, whereas, endophyte-alkaloids played a secondary role only reducing herbivore growth in the absence of Si supply. Conversely, in perennial ryegrass both Si and endophyte-alkaloids (regardless of Si supply) reduced herbivore RGR although not synergised. 4. Novel interactions between constitutive and induced Si- and alkaloid-based antiherbivore defences in grasses were observed. Overall, Si had a greater effect on the folivore than endophytes in both grasses. Endophyte-defences contributed more to herbivore resistance in perennial ryegrass than tall fescue. We demonstrate that Si and endophytes were not antagonistic and highlight that the protective nature of their interaction varies with the grass-endophyte species tested.

opencc-by-4.0Apr 2024View details →

Targeted Metabolite Analysis of alkaloids in Different tissues and Processed seeds of Strychnos nux-vomica using LC-Q-TOF-MSn

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opencc-by-4.0Jun 2024View details →

Impact of Rhizosphere Quantitative Microbiome and Soil Properties on Alkaloid Dynamics in Lycoris aurea

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opencc-zeroSep 2021View details →

Introduced populations of the garden lupine are adapted to local generalist snails but have lost alkaloid diversity

Intraspecific variation in growth and defence among plant populations can be driven by differences in (a)biotic conditions, such as herbivory and resources. Introduction of species to novel environments affects simultaneously herbivory encountered by a plant and resource availability both directly and via altered competitive environment. Here, we address the question of how growth (leaf mass per area (LMA), plant size) and resistance traits (leaf alkaloids, leaf trichomes, resistance to a generalist snail) vary and covary between native and introduced populations of the garden lupine, Lupinus polyphyllus. We focused specifically on evolved differences among populations by measuring traits from plants grown from seed in a common environment. Plants from the introduced populations were more resistant against the generalist snail, Arianta arbustorum, and they had more leaf trichomes and higher LMA than plants from the native populations. The composition of alkaloids differed between native and introduced populations, with the native populations having more diversity in alkaloids among them. Resistance was positively associated with plant size and LMA across all populations. Other trait associations differed between native and introduced areas, implying that certain trade-offs may be fundamentally different between native and introduced populations. Our results suggest that, for the introduced populations, the loss of native herbivores and the alterations in resource availability have led to a lower diversity in leaf alkaloids among populations and may facilitate the evolution of novel trait optima without compensatory trade-offs. Such phytochemical similarity among introduced populations provides novel insights into mechanisms promoting successful plant invasions.

Fig. 5 in Anti-inflammatory and cytotoxic carbazole alkaloids from Murraya kwangsiensis

Fig. 5. Calculated and experimental ECD spectra of compound 17 (A) and experimental ECD spectra of 7 and 10 (B).

opennotspecifiedJan 2023View details →

Fig. 5 in Alkaloids with cholinesterase inhibitory activities from the bulbs of Crinum × amabile Donn ex Ker Gawl

Fig. 5. Analysis of interactions between AChE and A) crystal (green) and re-docking (cyan) galanthamine structures, B) galanthamine, C) compound 29, as well as interactions between BuChE and D) crystal (violet red) and re-docking (pink) tacrine structures, E) galanthamine and F) compound 29. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Fig. 4 in An electrophysiological characterization of naturally occurring tobacco alkaloids and their action on human α4β2 and α7 nicotinic acetylcholine receptors

Fig. 4. Concentration–response curves were obtained by using the whole-cell mode of the patch-clamp technique at a holding potential of −70 mV from CHO cells stably expressing human α4β2 (continuous black lines) or human α7 (dotted grey lines) nAChRs. The lines represent the fits to the Hill equation for nicotine (1) (circles symbols), anabasine (12) (triangles symbols), nornicotine (7) (squared symbols), and S-anatabine (16) (diamonds symbols). The fit parameters are presented (Table 1). The averaged normalized current response is plotted as a function of the maximal current to ACh (ImaxACh). Two backgrounds highlight the concentration range of the tobacco alkaloids levels measured in human plasma (grey background with diagonal lines) and in human cerebrospinal fluid (grey background with horizontal lines). Data are presented as mean ± SD.

Fig. 3 in An electrophysiological characterization of naturally occurring tobacco alkaloids and their action on human α4β2 and α7 nicotinic acetylcholine receptors

Fig. 3. Sequential applications of brief ACh pulses are plotted as a function of time for three ACh concentrations. (a) EC20 = 0.4 μM (circles), EC50 = 1.2 μM (squares), EC90 = 11.1 μM (triangles) for human α4β2 receptors. (b) EC20 = 33.3 μM (circles), EC60 = 300 μM (squares), EC90 = 900 μM (triangles) for human α7 receptors. Experiments were performed by using the whole-cell mode of the patch-clamp technique at a holding potential of −70 mV in CHO cells stably expressing the human α4β2 and α7 nAChRs. EC, effective concentration. Data are presented as mean ± SD.

Fig. 2 in An electrophysiological characterization of naturally occurring tobacco alkaloids and their action on human α4β2 and α7 nicotinic acetylcholine receptors

Fig. 2. Representative traces of currents elicited by using the agonist mode (a and c) and PAM mode (b and d) in the whole-cell mode of the patch-clamp technique at a holding potential of −70 mV in CHO cells stably expressing human α4β2 (a and b) and human α7 (c and d) nAChRs. Agonist mode (a, c): 0.3% DMSO (left); 33.3 μM of the tobacco alkaloid anabasine (middle); 33.3 and 900 μM ACh for α4β2 and α7, respectively (right). PAM mode (b, d): 0.4 and 100 μM ACh for α4β2 and α7, respectively (left); co-application of 33.3 μM of the tobacco alkaloid trans-anatalline (middle); 0.4 or 100 μM ACh for α4β2 and α7, respectively (right). Thick dotted lines represent the pre-application period of the alkaloid (≥2 min). Thin dotted lines represent zero current.; PAM, positive allosteric modulator.

Fig. 1 in An electrophysiological characterization of naturally occurring tobacco alkaloids and their action on human α4β2 and α7 nicotinic acetylcholine receptors

Fig. 1. Representative traces of currents elicited in response to increasing concentrations of ACh. Currents were measured in agonist mode by using the whole-cell mode of the patch-clamp technique at a holding potential of −70 mV in CHO cells stably expressing human α4β2 (a) and human α7 (b) nAChRs. The half-maximal effective concentrations determined by using the Hill equation were 1.02 ± 1.0 μM (a) and 142 ± 16 μM (b) (n = 5–11 cells). Bars indicate (in μM): 0.1 (1), 0.4 (2), 1.2 (3), 3.7 (4), 11.1 (5), 33.3 (6), 100 (7), 300 (8), 900 (9), and 2700 (10). Dotted lines represent zero current.