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1.
New Phytol ; 237(2): 631-642, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36263711

RESUMEN

Plants are widely recognized as chemical factories, with each species producing dozens to hundreds of unique secondary metabolites. These compounds shape the interactions between plants and their natural enemies. We explore the evolutionary patterns and processes by which plants generate chemical diversity, from evolving novel compounds to unique chemical profiles. We characterized the chemical profile of one-third of the species of tropical rainforest trees in the genus Inga (c. 100, Fabaceae) using ultraperformance liquid chromatography-mass spectrometry-based metabolomics and applied phylogenetic comparative methods to understand the mode of chemical evolution. We show: each Inga species contain structurally unrelated compounds and high levels of phytochemical diversity; closely related species have divergent chemical profiles, with individual compounds, compound classes, and chemical profiles showing little-to-no phylogenetic signal; at the evolutionary time scale, a species' chemical profile shows a signature of divergent adaptation. At the ecological time scale, sympatric species were the most divergent, implying it is also advantageous to maintain a unique chemical profile from community members; finally, we integrate these patterns with a model for how chemical diversity evolves. Taken together, these results show that phytochemical diversity and divergence are fundamental to the ecology and evolution of plants.


Asunto(s)
Fabaceae , Metabolómica , Metabolismo Secundario , Filogenia , Bosque Lluvioso
2.
J Exp Bot ; 70(20): 5853-5864, 2019 10 24.
Artículo en Inglés | MEDLINE | ID: mdl-31257446

RESUMEN

Saplings in the shade of the tropical understorey face the challenge of acquiring sufficient carbon for growth as well as defence against intense pest pressure. A minor increase in light availability via canopy thinning may allow for increased investment in chemical defence against pests, but it may also necessitate additional biochemical investment to prevent light-induced oxidative stress. The shifts in secondary metabolite composition that increased sun exposure may precipitate in such tree species present an ideal milieu for evaluating the potential of a single suite of phenolic secondary metabolites to be used in mitigating both abiotic and biotic stressors. To conduct such an evaluation, we exposed saplings of two unrelated species to a range of light environments and compared changes in their foliar secondary metabolome alongside corresponding changes in the abiotic and biotic activity of their secondary metabolite suites. Among the numerous classes of secondary metabolites found in both species, phenolics accounted for the majority of increases in antioxidant and UV-absorbing properties as well as activity against an invertebrate herbivore and a fungal pathogen. Our results support the hypothesis that phenolics contribute to the capacity of plants to resist co-occurring abiotic and biotic stressors in resource-limited conditions.


Asunto(s)
Fenoles/metabolismo , Hojas de la Planta/metabolismo , Hojas de la Planta/fisiología , Árboles/metabolismo , Árboles/fisiología , Animales , Herbivoria , Metaboloma/genética , Metaboloma/fisiología , Hojas de la Planta/parasitología , Árboles/parasitología , Clima Tropical
3.
Science ; 363(6432): 1213-1216, 2019 03 15.
Artículo en Inglés | MEDLINE | ID: mdl-30872524

RESUMEN

Ecological theory predicts that the high local diversity observed in tropical forests is maintained by negative density-dependent interactions within and between closely related plant species. By using long-term data on tree growth and survival for coexisting Inga (Fabaceae, Mimosoideae) congeners, we tested two mechanisms thought to underlie negative density dependence (NDD): competition for resources and attack by herbivores. We quantified the similarity of neighbors in terms of key ecological traits that mediate these interactions, as well as the similarity of herbivore communities. We show that phytochemical similarity and shared herbivore communities are associated with decreased growth and survival at the sapling stage, a key bottleneck in the life cycle of tropical trees. None of the traits associated with resource acquisition affect plant performance, indicating that competition between neighbors may not shape local tree diversity. These results suggest that herbivore pressure is the primary mechanism driving NDD at the sapling stage.


Asunto(s)
Biodiversidad , Fabaceae/crecimiento & desarrollo , Bosques , Herbivoria , Árboles/crecimiento & desarrollo , Animales
4.
Front Plant Sci ; 9: 1237, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30190723

RESUMEN

Coevolutionary theory has long predicted that the arms race between plants and herbivores is a major driver of host selection and diversification. At a local scale, plant defenses contribute significantly to the structure of herbivore assemblages and the high alpha diversity of plants in tropical rain forests. However, the general importance of plant defenses in host associations and divergence at regional scales remains unclear. Here, we examine the role of plant defensive traits and phylogeny in the evolution of host range and species divergence in leaf-feeding sawflies of the family Argidae associated with Neotropical trees in the genus Inga throughout the Amazon, the Guiana Shield and Panama. Our analyses show that the phylogenies of both the sawfly herbivores and their Inga hosts are congruent, and that sawflies radiated at approximately the same time, or more recently than their Inga hosts. Analyses controlling for phylogenetic effects show that the evolution of host use in the sawflies associated with Inga is better correlated with Inga chemistry than with Inga phylogeny, suggesting a pattern of delayed host tracking closely tied to host chemistry. Finally, phylogenetic analyses show that sister species of Inga-sawflies are dispersed across the Neotropics, suggesting a role for allopatric divergence and vicariance in Inga diversification. These results are consistent with the idea that host defensive traits play a key role not only in structuring the herbivore assemblages at a single site, but also in the processes shaping host association and species divergence at a regional scale.

5.
New Phytol ; 218(2): 847-858, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29436716

RESUMEN

The need for species identification and taxonomic discovery has led to the development of innovative technologies for large-scale plant identification. DNA barcoding has been useful, but fails to distinguish among many species in species-rich plant genera, particularly in tropical regions. Here, we show that chemical fingerprinting, or 'chemocoding', has great potential for plant identification in challenging tropical biomes. Using untargeted metabolomics in combination with multivariate analysis, we constructed species-level fingerprints, which we define as chemocoding. We evaluated the utility of chemocoding with species that were defined morphologically and subject to next-generation DNA sequencing in the diverse and recently radiated neotropical genus Inga (Leguminosae), both at single study sites and across broad geographic scales. Our results show that chemocoding is a robust method for distinguishing morphologically similar species at a single site and for identifying widespread species across continental-scale ranges. Given that species are the fundamental unit of analysis for conservation and biodiversity research, the development of accurate identification methods is essential. We suggest that chemocoding will be a valuable additional source of data for a quick identification of plants, especially for groups where other methods fall short.


Asunto(s)
ADN de Plantas/genética , Fabaceae/anatomía & histología , Fabaceae/clasificación , Metabolómica/métodos , Geografía , Análisis Multivariante , Filogenia , América del Sur , Especificidad de la Especie
6.
Oecologia ; 187(2): 361-376, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29428967

RESUMEN

We summarize work on a speciose Neotropical tree genus, Inga (Fabaceae), examining how interspecific variation in anti-herbivore defenses may have evolved, how defenses shape host choice by herbivores and how they might regulate community composition and influence species radiations. Defenses of expanding leaves include secondary metabolites, extrafloral nectaries, rapid leaf expansion, trichomes, and synchrony and timing of leaf production. These six classes of defenses are orthogonal, supporting independent evolutionary trajectories. Moreover, only trichomes show a phylogenetic signature, suggesting evolutionary lability in nearly all defenses. The interspecific diversity in secondary metabolite profiles does not arise from the evolution of novel compounds, but from novel combinations of common compounds, presumably due to changes in gene regulation. Herbivore host choice is determined by plant defensive traits, not host phylogeny. Neighboring plants escape each other's pests if their defenses differ enough, thereby enforcing the high local diversity typical of tropical forests. Related herbivores feed on hosts with similar defenses, implying that there are phylogenetic constraints placed on the herbivore traits that are associated with host use. Divergence in defensive traits among Inga appears to be driven by herbivore pressure. However, the lack of congruence between herbivore and host phylogeny suggests that herbivores are tracking defenses, choosing hosts based on traits for which they already have adaptations. There is, therefore, an asymmetry in the host-herbivore evolutionary arms race.


Asunto(s)
Fabaceae , Herbivoria , Animales , Ecología , Filogenia , Hojas de la Planta , Bosque Lluvioso
7.
Proc Natl Acad Sci U S A ; 114(36): E7499-E7505, 2017 09 05.
Artículo en Inglés | MEDLINE | ID: mdl-28827317

RESUMEN

Coevolutionary models suggest that herbivores drive diversification and community composition in plants. For herbivores, many questions remain regarding how plant defenses shape host choice and community structure. We addressed these questions using the tree genus Inga and its lepidopteran herbivores in the Amazon. We constructed phylogenies for both plants and insects and quantified host associations and plant defenses. We found that similarity in herbivore assemblages between Inga species was correlated with similarity in defenses. There was no correlation with phylogeny, a result consistent with our observations that the expression of defenses in Inga is independent of phylogeny. Furthermore, host defensive traits explained 40% of herbivore community similarity. Analyses at finer taxonomic scales showed that different lepidopteran clades select hosts based on different defenses, suggesting taxon-specific histories of herbivore-host plant interactions. Finally, we compared the phylogeny and defenses of Inga to phylogenies for the major lepidopteran clades. We found that closely related herbivores fed on Inga with similar defenses rather than on closely related plants. Together, these results suggest that plant defenses might be more evolutionarily labile than the herbivore traits related to host association. Hence, there is an apparent asymmetry in the evolutionary interactions between Inga and its herbivores. Although plants may evolve under selection by herbivores, we hypothesize that herbivores may not show coevolutionary adaptations, but instead "chase" hosts based on the herbivore's own traits at the time that they encounter a new host, a pattern more consistent with resource tracking than with the arms race model of coevolution.


Asunto(s)
Fabaceae/genética , Fabaceae/parasitología , Herbivoria/genética , Interacciones Huésped-Parásitos/genética , Lepidópteros/genética , Animales , Evolución Biológica , Insectos/genética , Fenotipo , Filogenia , Hojas de la Planta/genética , Hojas de la Planta/parasitología
8.
Proc Natl Acad Sci U S A ; 114(10): 2645-2650, 2017 03 07.
Artículo en Inglés | MEDLINE | ID: mdl-28213498

RESUMEN

We investigate patterns of historical assembly of tree communities across Amazonia using a newly developed phylogeny for the species-rich neotropical tree genus Inga We compare our results with those for three other ecologically important, diverse, and abundant Amazonian tree lineages, Swartzia, Protieae, and Guatteria Our analyses using phylogenetic diversity metrics demonstrate a clear lack of geographic phylogenetic structure, and show that local communities of Inga and regional communities of all four lineages are assembled by dispersal across Amazonia. The importance of dispersal in the biogeography of Inga and other tree genera in Amazonian and Guianan rain forests suggests that speciation is not driven by vicariance, and that allopatric isolation following dispersal may be involved in the speciation process. A clear implication of these results is that over evolutionary timescales, the metacommunity for any local or regional tree community in the Amazon is the entire Amazon basin.


Asunto(s)
Biodiversidad , Filogenia , Bosque Lluvioso , Árboles/genética , Geografía , Especificidad de la Especie , Árboles/clasificación
9.
Chemosphere ; 172: 363-372, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28088026

RESUMEN

Tropospheric ozone (O3) is a major air pollutant and greenhouse gas, affecting carbon dynamics, ecological interactions, and agricultural productivity across continents and biomes. Elevated [O3] has been documented in tropical evergreen forests, the epicenters of terrestrial primary productivity and plant-consumer interactions. However, the effects of O3 on vegetation have not previously been studied in these forests. In this study, we quantified ambient O3 in a region shared by forests and urban/commercial zones in Panama and found levels two to three times greater than in remote tropical sites. We examined the effects of these ambient O3 levels on the growth and chemistry of seedlings of Ficus insipida, a regionally widespread tree with high stomatal conductance, using open-top chambers supplied with ozone-free or ambient air. We evaluated the differences across treatments in biomass and, using UPLC-MS-MS, leaf secondary metabolites and membrane lipids. Mean [O3] in ambient air was below the levels that induce chronic stress in temperate broadleaved trees, and biomass did not differ across treatments. However, leaf secondary metabolites - including phenolics and a terpenoid - were significantly downregulated in the ambient air treatment. Membrane lipids were present at lower concentrations in older leaves grown in ambient air, suggesting accelerated senescence. Thus, in a tree species with high O3 uptake via high stomatal conductance, current ambient [O3] in Panamanian forests are sufficient to induce chronic effects on leaf chemistry.


Asunto(s)
Ficus/química , Ozono/química , Hojas de la Planta/química , Plantones/química , Árboles/química , Biomasa , Carbono/química , Dióxido de Carbono/química , Bosques , Geografía , Análisis de los Mínimos Cuadrados , Panamá , Fenoles/química , Fotosíntesis , Terpenos/química
10.
Ecol Evol ; 6(17): 6037-49, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-27648224

RESUMEN

UNLABELLED: Theoretical and empirical studies show that, when past or current herbivory is a reliable cue of future attack and defenses are costly, defenses can be induced only when needed and thereby permit investment in other functions such as growth or reproduction. Theory also states that, in environments where herbivory is constantly high, constitutive defenses should be favored. Here, we present data to support the second aspect of the induced resistance hypothesis. We examined herbivore-induced responses for four species of Inga (Fabaceae), a common canopy tree in Neotropical forests. We quantified chemical defenses of expanding leaves, including phenolic, saponin and toxic amino acids, in experimental field treatments with and without caterpillars. Because young leaves lack fiber and are higher in protein than mature leaves, they typically lose >25% of their leaf area during the few weeks of expansion. We predicted that the high rates of attack would select for investment in constitutive defenses over induction. Our data show that chemical defenses were quite unresponsive to herbivory. We demonstrated that expanding leaves showed no or only small increases in investment in secondary metabolites, and no qualitative changes in the phenolic compound profile in response to herbivory. The proteinogenic amino acid tyrosine, which can be toxic at high concentrations, showed the greatest levels of induction. SYNTHESIS: These results provide some of the first support for theoretical predictions that the evolution of induced vs. constitutive defenses depends on the risk of herbivory. In habitats with constant and high potential losses to herbivores, such as tropical rainforests, high investments in constitutive defenses are favored over induction.

11.
New Phytol ; 212(4): 1007-1018, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27373446

RESUMEN

During droughts, leaves are predicted to act as 'hydraulic fuses' by shedding when plants reach critically low water potential (Ψplant ), thereby slowing water loss, stabilizing Ψplant and protecting against cavitation-induced loss of stem hydraulic conductivity (Ks ). We tested these predictions among trees in seasonally dry tropical forests, where leaf shedding is common, yet variable, among species. We tracked leaf phenology, Ψplant and Ks in saplings of six tree species distributed across two forests. Species differed in their timing and extent of leaf shedding, yet converged in shedding leaves as they approached the Ψplant value associated with a 50% loss of Ks and at which their model-estimated maximum sustainable transpiration rate approached zero. However, after shedding all leaves, the Ψplant value of one species, Genipa americana, continued to decline, indicating that water loss continued after leaf shedding. Ks was highly variable among saplings within species and seasons, suggesting a minimal influence of seasonal drought on Ks . Hydraulic limits appear to drive diverse patterns of leaf shedding among tropical trees, supporting the hydraulic fuse hypothesis. However, leaf shedding is not universally effective at stabilizing Ψplant , suggesting that the main function of drought deciduousness may vary among species.


Asunto(s)
Sequías , Modelos Biológicos , Hojas de la Planta/fisiología , Tallos de la Planta/fisiología , Estaciones del Año , Gases/metabolismo , Hojas de la Planta/anatomía & histología , Tallos de la Planta/anatomía & histología , Estomas de Plantas/fisiología , Especificidad de la Especie , Factores de Tiempo , Árboles/fisiología , Agua/fisiología
12.
Ecol Evol ; 6(2): 478-92, 2016 01.
Artículo en Inglés | MEDLINE | ID: mdl-26843932

RESUMEN

Selective pressures imposed by herbivores are often positively correlated with investments that plants make in defense. Research based on the framework of an evolutionary arms race has improved our understanding of why the amount and types of defenses differ between plant species. However, plant species are exposed to different selective pressures during the life of a leaf, such that expanding leaves suffer more damage from herbivores and pathogens than mature leaves. We hypothesize that this differential selective pressure may result in contrasting quantitative and qualitative defense investment in plants exposed to natural selective pressures in the field. To characterize shifts in chemical defenses, we chose six species of Inga, a speciose Neotropical tree genus. Focal species represent diverse chemical, morphological, and developmental defense traits and were collected from a single site in the Amazonian rainforest. Chemical defenses were measured gravimetrically and by characterizing the metabolome of expanding and mature leaves. Quantitative investment in phenolics plus saponins, the major classes of chemical defenses identified in Inga, was greater for expanding than mature leaves (46% and 24% of dry weight, respectively). This supports the theory that, because expanding leaves are under greater selective pressure from herbivores, they rely more upon chemical defense as an antiherbivore strategy than do mature leaves. Qualitatively, mature and expanding leaves were distinct and mature leaves contained more total and unique metabolites. Intraspecific variation was greater for mature leaves than expanding leaves, suggesting that leaf development is canalized. This study provides a snapshot of chemical defense investment in a speciose genus of tropical trees during the short, few-week period of leaf development. Exploring the metabolome through quantitative and qualitative profiling enables a more comprehensive examination of foliar chemical defense investment.

13.
Oecologia ; 179(4): 925-36, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26025573

RESUMEN

Tree species in seasonally dry tropical forests likely vary in their drought-survival mechanisms. Drought-deciduousness, which reduces water loss, and low wood density, which may permit dependence on stored water, are considered key traits. For saplings of six species at two distinct sites, we studied these and two associated traits: the seasonal amount of water released per stem volume ("water released") and the hydraulic capacitance of the stem (C). Two deciduous species with low stem density, Cavanillesia platanifolia and Bursera simaruba, had high C and high dry-season stem water potential (Ψ(stem)), but differed in dry-season water released. C. platanifolia did not use stored water during the dry season whereas B. simaruba, in a drier forest, released stored water. In both, water released was highest while flushing leaves, suggesting that stored water supports leaf flushing. In contrast, two deciduous species with intermediate stem density, Annona hayesii and Genipa americana, had intermediate C, low dry-season Ψ(stem), and high seasonal change in water released. Meanwhile, two evergreen species with intermediate stem density, Cojoba rufescens and Astronium graveolens, had relatively low C, low dry-season Ψ(stem), and intermediate seasonal change in water released. Thus, at least three, distinct stored-water-use strategies were observed. Additionally, bark relative water content (RWC) decreased along with Ψ(stem) during the dry season while xylem RWC did not change, suggesting that bark-stored water buffers Ψ(stem) seasonally. Together these results suggest that seasonal use of stored water and change in Ψ(stem) are associated with functional groups that are characterized by combinations of deciduousness and stem density.


Asunto(s)
Sequías , Bosques , Árboles/crecimiento & desarrollo , Clima Tropical , Agua/metabolismo , Annona/crecimiento & desarrollo , Annona/metabolismo , Bursera/crecimiento & desarrollo , Bursera/metabolismo , Gardenia/crecimiento & desarrollo , Gardenia/metabolismo , Malvaceae/crecimiento & desarrollo , Malvaceae/metabolismo , Panamá , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/metabolismo , Tallos de la Planta/crecimiento & desarrollo , Tallos de la Planta/metabolismo , Estaciones del Año , Árboles/metabolismo , Xilema/crecimiento & desarrollo , Xilema/metabolismo
14.
PLoS One ; 10(3): e0120351, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25811369

RESUMEN

In studies of ant-plant mutualisms, the role that ants play in increasing the growth rates of their plant partners is potentially a key beneficial service. In the field, we measured the growth of Cecropia glaziovii saplings and compared individuals that were naturally colonized by Azteca muelleri ants with uncolonized plants in different seasons (wet and dry). We also measured light availability as well as attributes that could be influenced by the presence of Azteca colonies, such as herbivory, leaf nutrients (total nitrogen and δ(15)N), and investments in defense (total phenolics and leaf mass per area). We found that colonized plants grew faster than uncolonized plants and experienced a lower level of herbivory in both the wet and dry seasons. Colonized plants had higher nitrogen content than uncolonized plants, although the δ(15)N, light environment, total phenolics and leaf mass per area, did not differ between colonized and uncolonized plants. Since colonized and uncolonized plants did not differ in the direct defenses that we evaluated, yet herbivory was lower in colonized plants, we conclude that biotic defenses were the most effective protection against herbivores in our system. This result supports the hypothesis that protection provided by ants is an important factor promoting plant growth. Since C. glaziovii is widely distributed among a variety of forests and ecotones, and since we demonstrated a strong relationship with their ant partners, this system can be useful for comparative studies of ant-plant interactions in different habitats. Also, given this study was carried out near the transition to the subtropics, these results help generalize the geographic distribution of this mutualism and may shed light on the persistence of the interactions in the face of climate change.


Asunto(s)
Hormigas , Plantas , Simbiosis , Animales , Clima , Herbivoria , Nitrógeno/química
15.
Proc Natl Acad Sci U S A ; 112(2): 442-7, 2015 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-25548168

RESUMEN

Understanding variation in resource specialization is important for progress on issues that include coevolution, community assembly, ecosystem processes, and the latitudinal gradient of species richness. Herbivorous insects are useful models for studying resource specialization, and the interaction between plants and herbivorous insects is one of the most common and consequential ecological associations on the planet. However, uncertainty persists regarding fundamental features of herbivore diet breadth, including its relationship to latitude and plant species richness. Here, we use a global dataset to investigate host range for over 7,500 insect herbivore species covering a wide taxonomic breadth and interacting with more than 2,000 species of plants in 165 families. We ask whether relatively specialized and generalized herbivores represent a dichotomy rather than a continuum from few to many host families and species attacked and whether diet breadth changes with increasing plant species richness toward the tropics. Across geographic regions and taxonomic subsets of the data, we find that the distribution of diet breadth is fit well by a discrete, truncated Pareto power law characterized by the predominance of specialized herbivores and a long, thin tail of more generalized species. Both the taxonomic and phylogenetic distributions of diet breadth shift globally with latitude, consistent with a higher frequency of specialized insects in tropical regions. We also find that more diverse lineages of plants support assemblages of relatively more specialized herbivores and that the global distribution of plant diversity contributes to but does not fully explain the latitudinal gradient in insect herbivore specialization.


Asunto(s)
Dieta , Herbivoria/fisiología , Insectos/fisiología , Animales , Biodiversidad , Ecosistema , Especificidad del Huésped , Insectos/clasificación , Lepidópteros/clasificación , Lepidópteros/fisiología , Modelos Biológicos , Filogenia
17.
PLoS One ; 8(9): e73192, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24066037

RESUMEN

Fungal endophytes--fungi that grow within plant tissues without causing immediate signs of disease--are abundant and diverse producers of bioactive secondary metabolites. Endophytes associated with leaves of tropical plants are an especially exciting and relatively untapped source of novel compounds. However, one major challenge in drug discovery lies in developing strategies to efficiently recover highly bioactive strains. As part of a 15-year drug discovery project, foliar endophytes were isolated from 3198 plant samples (51 orders, 105 families and at least 232 genera of angiosperms and ferns) collected in nine geographically distinct regions of Panama. Extracts from culture supernatants of >2700 isolates were tested for bioactivity (in vitro percent inhibition of growth, % IG) against a human breast cancer cell line (MCF-7) and the causative agents of malaria, leishmaniasis, and Chagas' disease. Overall, 32.7% of endophyte isolates were highly active in at least one bioassay, including representatives of diverse fungal lineages, host lineages, and collection sites. Up to 17% of isolates tested per assay were highly active. Most bioactive strains were active in only one assay. Fungal lineages differed in the incidence and degree of bioactivity, as did fungi from particular plant taxa, and greater bioactivity was observed in endophytes isolated from plants in cloud forests vs. lowland forests. Our results suggest that using host taxonomy and forest type to tailor plant collections, and selecting endophytes from specific orders or families for cultivation, will markedly increase the efficiency and efficacy of discovering bioactive metabolites for particular pharmaceutical targets.


Asunto(s)
Endófitos/metabolismo , Hongos/metabolismo , Plantas/microbiología , Antimaláricos/farmacología , Antineoplásicos/farmacología , Bioensayo/métodos , Línea Celular Tumoral , Humanos , Plantas/clasificación , Plasmodium falciparum/efectos de los fármacos , Tripanocidas/farmacología , Trypanosoma cruzi/efectos de los fármacos
18.
J Nat Prod ; 76(4): 741-4, 2013 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-23560689

RESUMEN

Two novel reddish-orange alkaloids, mycoleptodiscin A (1) and mycoleptodiscin B (2), were isolated from liquid cultures of the endophytic fungus Mycoleptodiscus sp. that had been isolated from Desmotes incomparabilis in Panama. Elucidation of their structures was accomplished using 1D and 2D NMR spectroscopy in combination with IR spectroscopic and MS data. These compounds are indole-terpenes with a new skeleton uncommon in nature. Mycoleptodiscin B (2) was active in inhibiting the growth of cancer cell lines with IC50 values in the range 0.60-0.78 µM.


Asunto(s)
Alcaloides/aislamiento & purificación , Alcaloides/farmacología , Antineoplásicos/aislamiento & purificación , Antineoplásicos/farmacología , Ascomicetos/química , Alcaloides/química , Antineoplásicos/química , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Concentración 50 Inhibidora , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Panamá , Espectrofotometría Infrarroja
19.
Tetrahedron Lett ; 53(13): 1624-1626, 2012 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-22707798

RESUMEN

Among thirty four endophytic fungal strains screened for in vitro antagonism, the endophytic fungus Cordyceps dipterigena was found to strongly inhibit mycelial growth of the plant pathogenic fungus Gibberella fujikuroi. Two new depsidone metabolites, cordycepsidone A (1) and cordycepsidone B (2), were isolated from the PDA culture extract of C. dipterigena and identified as being responsible for the antifungal activity. Elucidation of their chemical structures was carried out using 1D and 2D NMR spectroscopy in combination with IR and MS spectroscopic data. Cordycepsidone A displayed strong and dose-dependent antifungal activity against the plant pathogenic fungus Gibberella fujikuroi. The isolates were inactive in bioassays for malaria (Plasmodium falciparum), leishmaniasis (Leishmania donovani), Chagas's disease (Trypanosoma cruzi), and cytotoxicity at 10 µg/mL. The compounds were also found to be inactive against several bacterial strains at 50 µg/mL.

20.
Tetrahedron Lett ; 53(8): 919-922, 2012 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-25177062

RESUMEN

Three new terpenoids of mixed biosynthetic origin were isolated from the culture filtrate of the endophytic fungus Pycnoporus sanguineus. Their structures were determined by extensive spectroscopic analyses. We have named these tricyclic and tetracyclic metabolites 'coibanoles A-C' in reference to Coiba Island and Coiba National Park, Panamá, from which the plant and endophyte were collected. The extract was inactive to the human parasites Trypanosoma cruzi, Leishmania donovani, and Plasmodium falciparum at a test concentration of 10 µg/mL.

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