Out of the forest: past and present range expansion of a parthenogenetic weevil pest, or how to colonize the world successfully

Previous research revealed complex diversification patterns in the parthenogenetic weevil Naupactus cervinus. To understand the origin of clonal diversity and successful spreading of this weevil, we investigated its geographic origin and possible dispersal routes and whether parthenogens can persist in habitats under unsuitable environmental conditions. This study is based on samples taken throughout a broad area of the species’ range. We used both mitochondrial and nuclear markers and applied phylogenetic and network analyses to infer possible relationships between haplotypes. Bayesian phylogeographic analyses and ecological niche modeling were used to investigate the processes that shaped genetic diversity and enabled the colonization of new geographic areas. Southeastern Brazil emerges as the original distribution area of N. cervinus. We detected two range expansions, one along natural corridors during the Pleistocene and the other in countries outside South America during recent times. Isolation due to climate shifts during the early Pleistocene led to diversification in two divergent clades, which probably survived in different refugia of the Paranaense Forest and the Paraná River delta. The origin of the clonal diversity was probably a complex process including mutational diversification, hybridization, and secondary colonization. The establishment of N. cervinus in areas outside its native range may indicate adaptation to drier and cooler conditions. Parthenogenesis would be advantageous for the colonization of new environments by preventing the breakup of successful gene combinations. As in other insect pests, the present distribution of N. cervinus results from both its evolutionary history and its recent history related to human activities.Facultad de Ciencias Naturales y Muse

Evolution of a degradative bacterial consortium during the enrichment of naphtha solvent

A microbial mixed culture able to degrade naphtha solvent, a model of hydrocarbon aromatic mixture, was isolated from a hydrocarbon-polluted soil. Composition of the population was monitored by phenotypic and molecular methods applied on soil DNA, on whole enrichment culture DNA, and on 85 isolated strains. Strains were characterized for their 16S rDNA restriction profiles and for their random amplified polymorphic DNA profiles. Catabolic capabilities were monitored by phenotypic traits and by PCR assays for the presence of the catabolic genes methyl mono-oxygenase ( xylA,M), catechol 2,3 dioxygenase (xylE) and toluene dioxygenase (todC1) of TOL and TOD pathways. Different haplotypes belonging to Pseudomonas putida, Ps. aureofaciens and Ps. aeruginosa were found to degrade aromatic compounds and naphtha solvent. The intrinsic catabolic activity of the microbial population of the polluted site was detected by PCR amplification of the xylE gene directly from soil DNA

Potential geographic distributions of two parthenogenetic weevils (Coleoptera: Curculionidae) associated with citrus in Argentina and Brazil

Parapantomorus fluctuosus (Boheman) and Pantomorus cinerosus (Boheman) (both Coleoptera: Curculionidae) are parthenogenetic broad-nosed weevils native to South America, and they damage citrus in Argentina and Brazil. The objectives of this contribution are to apply ecological niche modelling to compare the suitable areas of occurrence of these species with those of other parthenogenetic Naupactini distributed in similar areas, and to analyze their potential range in relation to the distribution of citrus groves, mainly in Argentina and Brazil. Pantomorus cinerosus and P. fluctuosus were predicted to be distributed in tropical and subtropical South America, Mexico, Central America, Cuba, southeastern USA (Florida), southern Africa, Madagascar, eastern Australia, and southern China. However, neither has colonized other countries outside the native range. The potential distribution of P. fluctuosus is broader than that of P. cinerosus, and the predicted areas of both species are partially coincident with main production areas of citrus in Argentina, Brazil, and throughout the world. Although ecological niche modelling is an effective tool for predicting the potential spread and colonization of weevils in distant cultivated areas, weevil establishment is most likely the result of multiple factors.Parapantomorus fluctuosus (Boheman) y Pantomorus cinerosus (Boheman) (ambos Coleoptera: Curculionidae) son gorgojos partenogenéticos de rostro corto nativos de América del Sur, que causan daños en cítricos, en Argentina y Brasil. Los objetivos de esta contribución son realizar un análisis de modelado de nicho ecológico de estas especies, comparar las áreas óptimas modeladas con las de otras especies partenogenéticas de Naupactini de similar distribución, y analizar sus distribuciones potenciales con respecto a las zonas productoras de cítricos principalmente de Argentina y Brasil. De acuerdo con nuestros resultados, Parapantomorus fluctuosus y Pantomorus cinerosus presentan condiciones ambientales favorables en Sudamerica tropical y subtropical, América Central, México, Cuba, sureste de Estados Unidos (Florida), sur de África, Madagascar, este de Australia, y sur de China; sin embargo ninguna de ellas ha colonizado otros países fuera de su rango natural. La distribución potencial de P. fluctuosus es mas amplia que la de P. cinerosus y las áreas predichas para ambas especies son parcialmente coincidentes con las regiones de cultivo de cítricos en Argentina, Brasil y a lo largo del mundo. El modelado de nichos ecológicos es una herramienta de utilidad para estimar la posible dispersión y colonización a distancia de plagas de gorgojos, sin embargo, su establecimiento en dichas áreas sea probablemente el resultado de múltiples factores.Facultad de Ciencias Naturales y Muse

The local and average structure of Ba(Ti, Ce)O3 perovskite solid solution: effect of cerium concentration and particle size

The amazing properties of ferroelectric perovskite BaTiO3 (BT) and its solid solutions make them indispensable for many technological applications (e.g. multilayer capacitors). Unfortunately, the so-called `size effect' limits their use. Indeed, under a certain critical particle size, these materials show a suppression of the spontaneous polarization and thus of the ferroelectric properties. In pure nanometric BaTiO3, this is related to a certain local structural disorder. However, only a few studies have explored BT solid solutions, where the doping effect, coupled to the reduced particle size, can play an important role. Therefore, in this work, the structure of BaCexTi1\u2013xO3 (x = 0.02\u20130.20) was explored by traditional Rietveld method and Pair Distribution Function. Samples present a particle size from 80\u2013160 nm to 400\u20131000 nm depending on increasing x. The carbox approach was applied, investigating the evolution of the local structure, its modifications and the structural coherent correlation length, as a function of cerium amount. Results demonstrate a cooperative effect of composition and reduced size in the ferroelectricity loss. The two, in fact, contribute to intensify the local structural disorder, decreasing the structural coherent correlation length. The local structural disorder is thus confirmed to be a relevant factor in the ferroelectric properties degradation

Out of the forest: past and present range expansion of a parthenogenetic weevil pest, or how to colonize the world successfully

Previous research revealed complex diversification patterns in the parthenogenetic weevil Naupactus cervinus. To understand the origin of clonal diversity and successful spreading of this weevil, we investigated its geographic origin and possible dispersal routes and whether parthenogens can persist in habitats under unsuitable environmental conditions. This study is based on samples taken throughout a broad area of the species’ range. We used both mitochondrial and nuclear markers and applied phylogenetic and network analyses to infer possible relationships between haplotypes. Bayesian phylogeographic analyses and ecological niche modeling were used to investigate the processes that shaped genetic diversity and enabled the colonization of new geographic areas. Southeastern Brazil emerges as the original distribution area of N. cervinus. We detected two range expansions, one along natural corridors during the Pleistocene and the other in countries outside South America during recent times. Isolation due to climate shifts during the early Pleistocene led to diversification in two divergent clades, which probably survived in different refugia of the Paranaense Forest and the Paraná River delta. The origin of the clonal diversity was probably a complex process including mutational diversification, hybridization, and secondary colonization. The establishment of N. cervinus in areas outside its native range may indicate adaptation to drier and cooler conditions. Parthenogenesis would be advantageous for the colonization of new environments by preventing the breakup of successful gene combinations. As in other insect pests, the present distribution of N. cervinus results from both its evolutionary history and its recent history related to human activities.Facultad de Ciencias Naturales y Muse

Stable inversion clines in a grasshopper species group despite complex geographical history

Chromosomal inversions are known to play roles in adaptation and differentiation in many species. They involve clusters of correlated genes (i.e., loci in linkage disequilibrium, LD) possibly associated with environmental variables. The grasshopper "species complex" Trimerotropis pallidipennis comprises several genetic lineages distributed from North to South America in arid and semi-arid high-altitude environments. The southernmost lineage, Trimerotropis sp., segregates for four to seven putative inversions that display clinal variation, possibly through adaptation to temperate environments. We analysed chromosomal, mitochondrial and genome-wide single nucleotide polymorphism data in 19 Trimerotropis sp. populations mainly distributed along two altitudinal gradients (MS and Ju). Populations across Argentina comprise two main chromosomally and genetically differentiated lineages: one distributed across the southernmost border of the "Andes Centrales," adding evidence for a differentiation hotspot in this area; and the other widely distributed in Argentina. Within the latter, network analytical approaches to LD found three clusters of correlated loci (LD-clusters), with inversion karyotypes explaining >79% of the genetic variation. Outlier loci associated with environmental variables mapped to two of these LD-clusters. Furthermore, despite the complex geographical history indicated by population genetic analyses, the clines in inversion karyotypes have remained stable for more than 20 generations, implicating their role in adaptation and differentiation within this lineage. We hypothesize that these clines could be the consequence of a coupling between extrinsic postzygotic barriers and spatially varying selection along environmental gradients resulting in a hybrid zone. These results provide a framework for future investigations about candidate genes implicated in rapid adaptation to new environments.Peer reviewe

Nintedanib Treatment for Idiopathic Pulmonary Fibrosis Patients Who Have Been Switched from Pirfenidone Therapy: A Retrospective Case Series Study

BACKGROUND: The efficacy and effectiveness of nintedanib as a first-line therapy in idiopathic pulmonary fibrosis (IPF) patients have been demonstrated by clinical trials and real-life studies. Our aim was to examine the safety profile and effectiveness of nintedanib when it is utilized as a second-line treatment in subjects who have discontinued pirfenidone. METHODS: The medical charts of 12 patients who were switched from pirfenidone to nintedanib were examined retrospectively. The drug's safety was defined by the number of adverse events (AEs) that were reported; disease progression was evaluated based on the patient's vital status and changes in forced vital capacity (FVC) at 12-month follow-up. RESULTS: The numbers of patients experiencing AEs and of the AEs per patient in our study group didn't significantly differ with respect to a group of 56 individuals who were taking nintedanib as a first-line therapy during the study period (5/12 vs. 22/56; p = 0.9999, and 0.00 (0.00-1.00) vs. 0.00 (0.00-3.00); p = 0.517, respectively). Two out of the 3 patients who had been switched to nintedanib due to a rapid disease progression showed stabilized FVC values. CONCLUSIONS: Nintedanib was found to have an acceptable safety profile in the majority of the IPF patients switched from pirfenidone. Prospective studies are warranted to determine if the drug can effectively delay disease progression in these patients

The effect of reproductive system on invasiveness: lessons from South American weevils

Successful invasion of a species into novel, marginal areas often requires the ability to face different ecological characteristics than those prevailing in its native environment. In insects, one of the factors that affect invasiveness is the reproductive system. Unisexuality provides advantages because a single specimen can initiate a new population. Unisexual reproduction precludes breakup of genetic combinations that promote ecological specialization, although it may limit evolutionary potential for colonization. In order to assess the importance of the reproductive mode in the colonization ability of the weevils that are native to South America, we compared 1 bisexual and 2 parthenogenetic species that expanded their ranges in the last 2 centuries. First, for parthenogenetic species we tested clonality of the sample. Second, we proposed central and marginal areas through phylogeographic and habitat modeling analyses, and identified the pathways of dispersal for each species. Bisexual Naupactus xanthographus (Germar) (Coleoptera: Curculionidae) expanded its range westward to areas with similar environmental constraints than in its native ecosystem. Conversely, parthenogenetic Naupactus leucoloma Boheman and Naupactus cervinus Boheman (both Coleoptera: Curculionidae) invaded other continents where they had low to null predicted habitat suitability. While a single clone of N. cervinus successfully established around the world in areas with apparently adverse conditions, clones of N. leucoloma expanded their range to areas only moderately suitable. We conclude that parthenogenesis is a driver in these particular species for colonization of marginal habitats. However, N. cervinus also would have pre-existing adaptations that allowed it to establish in areas with apparently low potential to surviveLa colonización de áreas marginales a menudo requiere que la especie invasora sea capaz de enfrentar características ecológicas diferentes a aquellas que predominan en su área nativa. En los insectos, uno de los factores que afectan la capacidad invasiva figura el sistema reproductivo. La unisexualidad proporciona varias ventajas, entre ellas la capacidad de fundar una nueva población a partir de un único especimen y evitar la ruptura de las combinaciones genéticas que promueven la especialización ecológica, esta última puede limitar el potencial evolutivo para la colonización. A fin de evaluar la importancia del modo reproductivo en la capacidad colonizadora de un grupo de gorgojos nativos de Sudamérica, comparamos dos especies con reproducción partenogenética y una especie bisexual que expandieron su rango geográfico a lo largo de los últimos 200 años. Por un lado, para las especies partenogenéticas pusimos a prueba la hipótesis de reproducción clonal. Además, propusimos áreas centrales y marginales a través de análisis filogeográficos y de modelado ecológico del hábitat e identificamos las rutas de dispersión de cada especie. La especie bisexual Naupactus xanthographus (Germar) (Coleoptera: Curculionidae) expandió su rango hacia el oeste, estableciéndose en áreas con restricciones ambientales similares a las de su área nativa. Por el contrario, las especies partenogenéticas Naupactus leucoloma Boheman y Naupactus cervinus Boheman (ambos Coleoptera: Curculionidae) invadieron otros continentes, donde las predicciones de ocurrencia en base a las condiciones del hábitat son bajas a nulas. Un único clon de N. cervinus consiguió establecerse en áreas con condiciones aparentemente adversas y los clones de N. leucoloma solo expandieron su rango a áreas moderadamente adecuadas. Concluimos que la partenogénesis es un factor fundamental en la colonización exitosa de hábitats marginales de estos gorgojos. Sin embargo, N. cervinus tendría adaptaciones pre-existentes que le habrían permitido el establecimiento en áreas con un potencial aparentemente bajo para la supervivencia.Facultad de Ciencias Naturales y Muse

Synthesis of 3-benzylisoquinolines by domino imination/cycloisomerisation of 2-propargylbenzaldehydes

An easy entry to uncommon 2-propargylbenzaldehydes was developed. 2-propargylbenzaldehydes demonstrated to be suitable building blocks for the synthesis of 3-benzyl isoquinolines by microwave promoted domino imination/cycloisomerisation in the presence of ammonium acetate. A small library of 3-benzyl isoquinolines was obtained in good yields under mild reaction conditions. Two alternative plausible reaction mechanisms are proposed

Phenotypic plasticity and the colonization of new habitats : A study of a colonial spider in the Chaco region and the Cerrado

In social animals, group prey capture could facilitate colonization of new areas with low resource availability. Parawixia bistriata is a colonial spider inhabiting seasonal dry forests and mesic habitats in South America. Individuals capture prey as a group, which allows individuals to broaden their foraging niche by incorporating large prey that cannot be subdued in solitary captures. P. bistriata exhibits two behavioural ecotypes a “dry” (plastic) ecotype which modifies individual’s tendency to capture prey in a group depending on food resources and a “wet” (fixed) ecotype, whose tendency to group prey capture is only modulated by the size of the prey but not by prey availability. By reconstructing the range expansion of the species using phylogeographic and species distribution modelling techniques, we indirectly examined whether group prey capture could have helped P. bistriata in colonization of low resource habitats. Based on cytochrome c oxidase subunit I gene genealogy, we found older populations in northern Cerrado in Brazil with more recent populations located further south in Dry and Humid Chaco in Argentina, with the latter being the most derived. Species distribution modelling for each ecotype suggests that suitable habitat for each ecotype started to overlap at some point during the Last Glacial Maximum (21 ky BP). These results suggest that P. bistriata expanded from northern Cerrado south to the Gran Chaco, being able to colonize mesic habitats at a later stage when individuals reached southern territories in the Chaco. This evidence is opposite to the idea that GPC facilitated P. bistriata colonization from mesic to harsher environments. However, plasticity in group prey capture could have been important to allow individuals to establish in mesic habitats by reducing the cost of group capture when under high resource levels.Facultad de Ciencias Naturales y Muse