ABSTRACT
Invasive species often possess a great capacity to adapt to novel environments in the form of spatial trait variation, as a result of varying selection regimes, genetic drift, or plasticity. We explored the geographic differentiation in several phenotypic traits related to plant growth, reproduction, and defense in the highly invasive Centaurea solstitialis by measuring neutral genetic differentiation (F ST), and comparing it with phenotypic differentiation (P ST), in a common garden experiment in individuals originating from regions representing the species distribution across five continents. Native plants were more fecund than non-native plants, but the latter displayed considerably larger seed mass. We found indication of divergent selection for these two reproductive traits but little overall genetic differentiation between native and non-native ranges. The native versus invasive P ST-F ST comparisons demonstrated that, in several invasive regions, seed mass had increased proportionally more than the genetic differentiation. Traits displayed different associations with climate variables in different regions. Both capitula numbers and seed mass were associated with winter temperature and precipitation and summer aridity in some regions. Overall, our study suggests that rapid evolution has accompanied invasive success of C. solstitialis and provides new insights into traits and their genetic bases that can contribute to fitness advantages in non-native populations.
ABSTRACT
Centaurea solstitialis L. (yellow starthistle, Asteraceae) is a Eurasian native plant introduced as an exotic into North and South America, and Australia, where it is regarded as a noxious invasive. Changes in ploidy level have been found to be responsible for numerous plant biological invasions, as they are involved in trait shifts critical to invasive success, like increased growth rate and biomass, longer life-span, or polycarpy. C. solstitialis had been reported to be diploid (2n = 2x = 16 chromosomes), however, actual data are scarce and sometimes contradictory. We determined for the first time the absolute nuclear DNA content by flow cytometry and estimated ploidy level in 52 natural populations of C. solstitialis across its native and non-native ranges, around the world. All the C. solstitialis populations screened were found to be homogeneously diploid (average 2C value of 1.72 pg, SD = ±0.06 pg), with no significant variation in DNA content between invasive and non-invasive genotypes. We did not find any meaningful difference among the extensive number of native and non-native C. solstitialis populations sampled around the globe, indicating that the species invasive success is not due to changes in genome size or ploidy level.
ABSTRACT
Alzheimer's disease (AD) is a progressive and neurodegenerative disorder and one of the current therapies involves strengthening the cholinergic tone in central synapses. Neuroprotective properties for nicotine have been described in AD, through its actions on nicotinic receptors and the further activation of the PI3K/Akt/Bcl-2 survival pathway. We have tested a quinolizidine alkaloid extract (TM0112) obtained from Teline monspessulanna (L.) K. Koch seeds to evaluate its action on nicotinic acetylcholine receptor (nAChR) in a neuronal AD model. Our data show that PC-12 cells pretreated with amyloid-ß (Aß) peptide for 24 h in presence of TM0112 modified Aß-reduction on cellular viability (Aß = 80 ± 3%; +TM0112 = 113 ± 4%, n = 15). In addition, this effect was blocked with atropine, MLA, and α-BTX (+TM0112+atropine = 87 ± 4%; +TM0112+MLA = 86 ± 4%; +TM0112+α-BTX = 92 ± 3%). Furthermore, similar protective effects were observed in rat cortical neurons (Aß = 63 ± 6%; +TM0112 = 114 ± 8%), but not in HEK293T cells (Aß = 61.4 ± 6.1%; +TM0112 = 62.8 ± 5.2) that do not express α7 nAChR. Moreover, the frequency of synaptic activity in the neuronal network (Aß = 51.6 ± 16.9%; +TM0112 = 210.8 ± 47.9%, n > 10), as well as the intracellular Ca2+ transients were recovered by TM0112 (Aß = 61.4 ± 6.9%; +TM0112 = 112.0 ± 5.7%; n = 3) in rat hippocampal neurons. TM0112 increased P-Akt, up to 250% with respect to control, and elevated Bcl-2/Bax percentage (Aß = 61.0 ± 8.2%; +TM0112 = 105.4 ± 19.5%, n = 4), suggesting a coupling between nAChR activation and an intracellular neuroprotective pathway. Our results suggest that TM0112 could be a new potential source for anti-AD drugs.
Subject(s)
Alkaloids/pharmacology , Alzheimer Disease/drug therapy , Neurons/drug effects , Neuroprotective Agents/pharmacology , Quinolizidines/pharmacology , Receptors, Nicotinic/metabolism , Alzheimer Disease/physiopathology , Amyloid beta-Peptides/toxicity , Animals , Cell Survival/drug effects , Cells, Cultured , Cerebral Cortex/drug effects , Cerebral Cortex/physiopathology , Fabaceae , HEK293 Cells , Humans , Neurons/physiology , PC12 Cells , Peptide Fragments/toxicity , Phytotherapy , Plant Extracts/pharmacology , Rats , Rats, Sprague-Dawley , Seeds , Synaptic Transmission/drug effectsABSTRACT
The essential oil chemical profile of Adesmia bijuga Phil. leaves, an endemic Chilean species from Maule Region central Chile with a critically endangered situation, was investigated for first time. This essential oil was isolated by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS). As a result, 29 components were identified; representing 94.8 percent of the oil composition. The major constituents were spathulenol (24.3 percent), cadalene (9.6 percent), alpha-copaene (8.5 percent) and ledol (8 percent).
La composición química del aceite esencial de las hojas frescas de Adesmia bijuga Phil., una especie chilena endémica de la Región del Maule, Chile central, en peligro crítico, fue investigada por primera vez. El aceite esencial fue aislado por hidrodestilación y analizado por cromatografía de gases acoplada a espectrometría de masas (CG-EM). Como resultado, se identificaron 29 compuestos, representando 94,8 por ciento de la composición del aceite. Los constituyentes mayoritarios fueron espatulenol (24,3 por ciento), cadaleno (9.6 por ciento), alfa-copaeno (8.5 por ciento) y ledol (8 por ciento).
Subject(s)
Oils, Volatile/chemistry , Fabaceae/chemistry , Plant Leaves/chemistry , Sesquiterpenes/analysis , Chile , Endangered Species , Gas Chromatography-Mass Spectrometry , Terpenes/analysisABSTRACT
Epicuticular components were obtained using methylene chloride extraction of fresh leaves from two populations of Lithrea caustica. The methylene chloride extracts were analyzed using GC and GC-MS. The extracts from both sampled populations showed a mixture of a hydrocarbon fraction of n-alkanes from C-21 to C-33 as their main components and small amounts of monoterpene hydrocarbons. The allergen 3-(pentadec-10-enyl)-catechol was also identified in the epicuticular sample in very different proportions in both extracts. A second extract obtained after the epicuticle had been removed from the sample revealed oxygenated monoterpenes, sesquiterpene hydrocarbons and an increased amount of the allergen 3-(Pentadec-10-enyl)-catechol. These results demonstrate that the cuticle hydrocarbons of the leaves function as a lipophylic barrier that controls allergen release.
Los componentes epicuticulares se obtuvieron mediante la extracción con cloruro de metileno de hojas frescas de dos poblaciones de Lithrea caustica. Los extractos de cloruro de metileno fueron analizados mediante CG y CG-EM. Los extractos de ambas poblaciones mostraron una mezcla de una fracción de hidrocarburos n-alcanos de C-21 a C-33 como sus componentes principales y pequeñas cantidades de hidrocarburos monoterpenicos. El alérgeno 3 - (pentadec-10-enil)-catecol también fue identificado en epicuticula en proporciones muy diferentes en ambos extractos. Un segundo extracto obtenido después que la epicutícula había sido eliminada de la muestra mostró monoterpenos oxigenados, hidrocarburos sesquiterpenos y una mayor cantidad del alérgeno 3 - (Pentadec-10-enil)-catecol. Estos resultados demuestran que los hidrocarburos de la cutícula de las hojas funcionan como una barrera lipofílica que controla la liberación del alérgeno.
