Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 48
Filtrar
1.
J. physiol. biochem ; 79(1): 235–249, feb. 2023. graf
Artigo em Inglês | IBECS | ID: ibc-215728

RESUMO

We have investigated the effects of melatonin on major pathways related with cellular proliferation and energetic metabolism in pancreatic stellate cells. In the presence of melatonin (1 mM, 100 µM, 10 µM, or 1 µM), decreases in the phosphorylation of c-Jun N-terminal kinase and of p44/42 and an increase in the phosphorylation of p38 were observed. Cell viability dropped in the presence of melatonin. A rise in the phosphorylation of AMP-activated protein kinase was detected in the presence of 1 mM and 100 µM melatonin. Treatment with 1 mM melatonin decreased the phosphorylation of protein kinase B, whereas 100 µM and 10 µM melatonin increased its phosphorylation. An increase in the generation of mitochondrial reactive oxygen species and a decrease of mitochondrial membrane potential were noted following melatonin treatment. Basal and maximal respiration, ATP production by oxidative phosphorylation, spare capacity, and proton leak dropped in the presence of melatonin. The expression of complex I of the mitochondrial respiratory chain was augmented in the presence of melatonin. Conversely, in the presence of 1 mM melatonin, decreases in the expression of mitofusins 1 and 2 were detected. The glycolysis and the glycolytic capacity were diminished in cells treated with 1 mM or 100 µM melatonin. Increases in the expression of phosphofructokinase-1 and lactate dehydrogenase were noted in cells incubated with 100 µM, 10 µM, or 1 µM melatonin. The expression of glucose transporter 1 was increased in cells incubated with 10 µM or 1 µM melatonin. Conversely, 1 mM melatonin decreased the expression of all three proteins. Our results suggest that melatonin, at pharmacological concentrations, might modulate mitochondrial physiology and energy metabolism in addition to major pathways involved in pancreatic stellate cell proliferation. (AU)


Assuntos
Humanos , Melatonina/farmacologia , Células Estreladas do Pâncreas , Mitocôndrias/metabolismo , Fosforilação Oxidativa , Proliferação de Células
2.
J Physiol Biochem ; 79(1): 235-249, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36334253

RESUMO

We have investigated the effects of melatonin on major pathways related with cellular proliferation and energetic metabolism in pancreatic stellate cells. In the presence of melatonin (1 mM, 100 µM, 10 µM, or 1 µM), decreases in the phosphorylation of c-Jun N-terminal kinase and of p44/42 and an increase in the phosphorylation of p38 were observed. Cell viability dropped in the presence of melatonin. A rise in the phosphorylation of AMP-activated protein kinase was detected in the presence of 1 mM and 100 µM melatonin. Treatment with 1 mM melatonin decreased the phosphorylation of protein kinase B, whereas 100 µM and 10 µM melatonin increased its phosphorylation. An increase in the generation of mitochondrial reactive oxygen species and a decrease of mitochondrial membrane potential were noted following melatonin treatment. Basal and maximal respiration, ATP production by oxidative phosphorylation, spare capacity, and proton leak dropped in the presence of melatonin. The expression of complex I of the mitochondrial respiratory chain was augmented in the presence of melatonin. Conversely, in the presence of 1 mM melatonin, decreases in the expression of mitofusins 1 and 2 were detected. The glycolysis and the glycolytic capacity were diminished in cells treated with 1 mM or 100 µM melatonin. Increases in the expression of phosphofructokinase-1 and lactate dehydrogenase were noted in cells incubated with 100 µM, 10 µM, or 1 µM melatonin. The expression of glucose transporter 1 was increased in cells incubated with 10 µM or 1 µM melatonin. Conversely, 1 mM melatonin decreased the expression of all three proteins. Our results suggest that melatonin, at pharmacological concentrations, might modulate mitochondrial physiology and energy metabolism in addition to major pathways involved in pancreatic stellate cell proliferation.


Assuntos
Melatonina , Melatonina/farmacologia , Células Estreladas do Pâncreas , Mitocôndrias/metabolismo , Fosforilação Oxidativa , Proliferação de Células
3.
Gastroenterol. hepatol. (Ed. impr.) ; 45(9): 652-659, Nov. 2022. ilus, tab, graf
Artigo em Inglês | IBECS | ID: ibc-210876

RESUMO

Background: Ultra-short coeliac disease (USCD) is a novel celiac disease (CD) subtype limited to the duodenal bulb (D1). HLA haplotypes and flow cytometry have not been assessed yet. Aims: To compare genetic, clinical, serologic, histopathologic and inmmunophenotypic parameters between USCD and conventional celiac disease (CCD) patients. Methods: Prospective single-center study in children and adult patients undergoing duodenal biopsies on a gluten-containing diet. Biopsies for histology and flow cytometry were taken separately from D1 and distal duodenum. Biopsies in seronegative patients with celiac lymphogram were repeated after 2 years on a gluten-free diet. Results: Among 505 included patients, 127 were diagnosed with CD, of whom 7 (5.5%) showed USCD. HLADQ2 was significantly less common in USCD compared to CCD (71% vs. 95%, p 0.003). Likewise, USCD patients showed more frequent non-significant seronegativity (28% vs. 8%, p 0.07) and significantly lower titrations (7–15IU/ml) of tissue transglutaminase antibodies (tTG-IgA) (60% vs. 13%, p<0.001). Biopsies from D1 revealed significant less NK cells down-expression in USCD patients (1.4 vs. 5, p 0.04). Conclusions: Up to 5.5% of CD patients showed USCD. A lower frequency of HLADQ2, along with less serum tTG-IgA titration and duodenal NK cell suppression, were differential features of USCD.(AU)


Antecedentes: La enfermedad celiaca ultracorta (ECUC) es un nuevo fenotipo de la enfermedad celiaca, que afecta exclusivamente al bulbo duodenal (D1), cuyas características genéticas e inmunológicas no han sido descritas. Objetivos: Comparar las características genéticas, clínicas, serológicas, histológicas e inmunológicas entre ECUC y enfermedad celiaca convencional (ECC). Métodos: Estudio prospectivo, unicéntrico, en el que se realizaron biopsias duodenales a pacientes adultos y pediátricos que seguían una dieta con gluten. Se realizó análisis histológico y por citometría de flujo por separado de duodeno distal y D1. En pacientes seronegativos con histología o linfograma concordante con EC, se repitió la biopsia tras 2 años con dieta sin gluten. Resultados: Se incluyeron 505 pacientes, siendo diagnosticados 127 de enfermedad celiaca, de los cuales 7 (5,5%) tenían ECUC. Los pacientes con ECUC expresaron el haplotipo DQ2 con menor frecuencia que en la ECC (71% vs. 95%, p 0,003) y presentaron mayor seronegatividad (28% vs. 8%, p 0,07) y, de manera significativa, titulaciones bajas de anticuerpos antitransglutaminasa (7-15IU/ml) (60% vs. 13%, p < 0,001). Comparado con la ECC, la citometría de flujo en las biopsias bulbares reveló una reducción atenuada significativa de células NK (1,4 vs. 5, p 0,04) en pacientes con ECUC. Conclusiones: Un 5,5% de los pacientes celiacos presentaron ECUC. Comparada con la ECC, las características diferenciales de la ECUC son menor expresión de HLADQ2, títulos más bajos de anticuerpos antitranglutaminasa y menor supresión de células NK a nivel bulbar.(AU)


Assuntos
Humanos , Criança , Adulto , Doença Celíaca , Hipersensibilidade a Trigo , Fenótipo , Doenças Raras , Citometria de Fluxo , Biópsia , Glutens/efeitos adversos , Sorotipagem , Estudos Prospectivos , Doenças Inflamatórias Intestinais , Gastroenterologia
4.
Gastroenterol Hepatol ; 45(9): 652-659, 2022 Nov.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-35489585

RESUMO

BACKGROUND: Ultra-short coeliac disease (USCD) is a novel celiac disease (CD) subtype limited to the duodenal bulb (D1). HLA haplotypes and flow cytometry have not been assessed yet. AIMS: To compare genetic, clinical, serologic, histopathologic and inmmunophenotypic parameters between USCD and conventional celiac disease (CCD) patients. METHODS: Prospective single-center study in children and adult patients undergoing duodenal biopsies on a gluten-containing diet. Biopsies for histology and flow cytometry were taken separately from D1 and distal duodenum. Biopsies in seronegative patients with celiac lymphogram were repeated after 2 years on a gluten-free diet. RESULTS: Among 505 included patients, 127 were diagnosed with CD, of whom 7 (5.5%) showed USCD. HLADQ2 was significantly less common in USCD compared to CCD (71% vs. 95%, p 0.003). Likewise, USCD patients showed more frequent non-significant seronegativity (28% vs. 8%, p 0.07) and significantly lower titrations (7-15IU/ml) of tissue transglutaminase antibodies (tTG-IgA) (60% vs. 13%, p<0.001). Biopsies from D1 revealed significant less NK cells down-expression in USCD patients (1.4 vs. 5, p 0.04). CONCLUSIONS: Up to 5.5% of CD patients showed USCD. A lower frequency of HLADQ2, along with less serum tTG-IgA titration and duodenal NK cell suppression, were differential features of USCD.


Assuntos
Doença Celíaca , Adulto , Criança , Humanos , Doença Celíaca/genética , Doença Celíaca/diagnóstico , Transglutaminases , Estudos Prospectivos , Proteínas de Ligação ao GTP , Proteína 2 Glutamina gama-Glutamiltransferase , Duodeno/patologia , Autoanticorpos , Biópsia , Imunoglobulina A
5.
Ecol Evol ; 10(9): 3991-4008, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32489626

RESUMO

Understanding the processes that shape neutral and adaptive genomic variation is a fundamental step to determine the demographic and evolutionary dynamics of pest species. Here, we use genomic data obtained via restriction site-associated DNA sequencing to investigate the genetic structure of Moroccan locust (Dociostaurus maroccanus) populations from the westernmost portion of the species distribution (Iberian Peninsula and Canary Islands), infer demographic trends, and determine the role of neutral versus selective processes in shaping spatial patterns of genomic variation in this pest species of great economic importance. Our analyses showed that Iberian populations are characterized by high gene flow, whereas the highly isolated Canarian populations have experienced strong genetic drift and loss of genetic diversity. Historical demographic reconstructions revealed that all populations have passed through a substantial genetic bottleneck around the last glacial maximum (~21 ka BP) followed by a sharp demographic expansion at the onset of the Holocene, indicating increased effective population sizes during warm periods as expected from the thermophilic nature of the species. Genome scans and environmental association analyses identified several loci putatively under selection, suggesting that local adaptation processes in certain populations might not be impeded by widespread gene flow. Finally, all analyses showed few differences between outbreak and nonoutbreak populations. Integrated pest management practices should consider high population connectivity and the potential importance of local adaptation processes on population persistence.

6.
Clin Gastroenterol Hepatol ; 18(1): 89-98, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-30978536

RESUMO

BACKGROUND & AIMS: Due to the poor eradication rates of standard triple therapy, the addition of bismuth salts has been proposed for first-line eradication of Helicobacter pylori. We assessed the effectiveness and safety of the combination of bismuth and the standard, clarithromycin-containing triple therapy in eradication of H pylori infection, using data from a large multi-center registry. METHODS: We performed an interim analysis of data from the European Registry on H pylori Management, a prospective trial registering clinical data and outcomes from infected patients from 27 countries in Europe since 2013. We extracted data on 1141 treatment-naïve patients who received first-line treatment with bismuth salts (240 mg) and a proton pump inhibitor (57% received esomeprazole, 18% received omeprazole, 11% received pantoprazole, and 14% received rabeprazole), amoxicillin (1 g), and clarithromycin (500 mg), all taken twice daily. RESULTS: Intention to treat and per-protocol rates of eradication were 88% and 94%, respectively. Intention to treat eradication increased to 93% in patients who received 14-day treatments. Adverse events occurred in 36% of patients; 76% of these events were mild, with a mean duration of 6 days. In multivariate analysis, eradication was associated with treatment compliance (odds ratio [OR], 13.0), a double dose (equivalent to 40 mg omeprazole) of proton pump inhibitor (OR, 4.7), and 14-day duration of treatment (OR, 2.0). CONCLUSIONS: In an analysis of data from a large multi-center registry, we found the addition of bismuth to 14-day standard triple therapy with clarithromycin and amoxicillin to eradicate H pylori infection in more than 90% of patients, based on intention to treat analysis, with an acceptable safety profile and level of adherence. ClinicalTrials.gov no: NCT02328131.


Assuntos
Amoxicilina/administração & dosagem , Anti-Infecciosos/administração & dosagem , Bismuto/administração & dosagem , Claritromicina/administração & dosagem , Infecções por Helicobacter/tratamento farmacológico , Helicobacter pylori , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Farmacorresistência Bacteriana Múltipla , Quimioterapia Combinada , Europa (Continente) , Feminino , Infecções por Helicobacter/complicações , Infecções por Helicobacter/virologia , Humanos , Masculino , Pessoa de Meia-Idade , Inibidores da Bomba de Prótons/administração & dosagem , Sistema de Registros , Resultado do Tratamento , Adulto Jovem
7.
Mol Ecol ; 28(9): 2155-2172, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30937976

RESUMO

Inferring the processes underlying spatial patterns of genomic variation is fundamental to understand how organisms interact with landscape heterogeneity and to identify the factors determining species distributional shifts. Here, we use genomic data (restriction site-associated DNA sequencing) to test biologically informed models representing historical and contemporary demographic scenarios of population connectivity for the Iberian cross-backed grasshopper Dociostaurus hispanicus, a species with a narrow distribution that currently forms highly fragmented populations. All models incorporated biological aspects of the focal taxon that could hypothetically impact its geographical patterns of genomic variation, including (a) spatial configuration of impassable barriers to dispersal defined by topographic landscapes not occupied by the species; (b) distributional shifts resulting from the interaction between the species bioclimatic envelope and Pleistocene glacial cycles; and (c) contemporary distribution of suitable habitats after extensive land clearing for agriculture. Spatiotemporally explicit simulations under different scenarios considering these aspects and statistical evaluation of competing models within an Approximate Bayesian Computation framework supported spatial configuration of topographic barriers to dispersal and human-driven habitat fragmentation as the main factors explaining the geographical distribution of genomic variation in the species, with no apparent impact of hypothetical distributional shifts linked to Pleistocene climatic oscillations. Collectively, this study supports that both historical (i.e., topographic barriers) and contemporary (i.e., anthropogenic habitat fragmentation) aspects of landscape composition have shaped major axes of genomic variation in the studied species and emphasizes the potential of model-based approaches to gain insights into the temporal scale at which different processes impact the demography of natural populations.


Assuntos
Genética Populacional , Gafanhotos/genética , Modelos Genéticos , Animais , Variação Genética , Gafanhotos/fisiologia , Espanha , Análise Espaço-Temporal
8.
Sci Rep ; 8(1): 13436, 2018 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-30194365

RESUMO

Inferring the demographic history of species is fundamental for understanding their responses to past climate/landscape alterations and improving our predictions about the future impacts of the different components of ongoing global change. Estimating the time-frame at which population fragmentation took place is also critical to determine whether such process was shaped by ancient events (e.g. past climate/geological changes) or if, conversely, it was driven by recent human activities (e.g. habitat loss). We employed genomic data (ddRAD-Seq) to determine the factors shaping contemporary patterns of genetic variation in the Iberian cross-backed grasshopper Dociostaurus crassiusculus, an endangered species with limited dispersal capacity and narrow habitat requirements. Our analyses indicate the presence of two ancient lineages and three genetic clusters resulted from historical processes of population fragmentation (~18-126 ka) that predate the Anthropocene. Landscape genetic analyses indicate that the limits of major river basins are the main geographical feature explaining large-scale patterns of genomic differentiation, with no apparent effect of human-driven habitat fragmentation. Overall, our study highlights the importance of detailed phylogeographic, demographic and spatially-explicit landscape analyses to identify evolutionary significant units and determine the relative impact of historical vs. anthropogenic factors on processes of genetic fragmentation in taxa of great conservation concern.


Assuntos
Conservação dos Recursos Naturais , Variação Genética , Genoma , Gafanhotos/genética , Sequenciamento de Nucleotídeos em Larga Escala , Animais , Gafanhotos/classificação , Região do Mediterrâneo
10.
United European Gastroenterol J ; 6(1): 29-37, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29435311

RESUMO

OBJECTIVES: Epidemiologic studies on eosinophilic esophagitis (EoE) are scarce and patient responders to proton pump inhibitor (PPI) therapy have usually been excluded. We aimed to evaluate population-based incidence rates, prevalence and trends in adult EoE over the past decade, including responders to PPI therapy. METHODS: We conducted an analysis of a prospectively established case registry in the health area of Cáceres, located in midwestern Spain. From the first EoE case diagnosed in 2007, endoscopy and pathology reports up to December 2016 were manually reviewed. A baseline diagnosis of EoE was confirmed upon symptoms of esophageal dysfunction (dysphagia/food impaction) and esophageal eosinophilia ≥ 15 eos/HPF. All patients were re-evaluated on PPI therapy during follow-up. RESULTS: A total of 137 patients were diagnosed with EoE during the study period, of whom 63 (46%) achieved clinicohistologic remission on PPI therapy. The prevalence of autoimmune disorders was low. Mean incidence rate was 8.09 new cases/100,000 inhabitants/year, increasing to 9.95 during the last lustrum and peaking in 2016 with 13.7. This trend coincided with late declining of esophageal biopsies rate. Overall prevalence in 2016 was 81.73 patients/100,000 inhabitants, with the highest prevalence in males between age 35 and 44 years (273 cases/100,000). No seasonal variation was observed in the diagnosis of EoE (53% during pollen season vs. 47%, p = 0.4). CONCLUSIONS: In midwestern Spain, incidence (13.7 cases/100,000 inhabitants/year) and prevalence (81.73 patients/100,000 inhabitants) in 2016 have grown remarkably in just one decade, coming closer to those figures recently reported for Crohn's disease in Spain.

11.
Mol Ecol ; 27(5): 1229-1244, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29411440

RESUMO

Although resolving phylogenetic relationships and establishing species limits are primary goals of systematics, these tasks remain challenging at both conceptual and analytical levels. Here, we integrated genomic and phenotypic data and employed a comprehensive suite of coalescent-based analyses to develop and evaluate competing phylogenetic and species delimitation hypotheses in a recent evolutionary radiation of grasshoppers (Chorthippus binotatus group) composed of two species and eight putative subspecies. To resolve the evolutionary relationships within this complex, we first evaluated alternative phylogenetic hypotheses arising from multiple schemes of genomic data processing and contrasted genetic-based inferences with different sources of phenotypic information. Second, we examined the importance of number of loci, demographic priors, number and kind of phenotypic characters and sex-based trait variation for developing alternative species delimitation hypotheses. The best-supported topology was largely compatible with phenotypic data and showed the presence of two clades corresponding to the nominative species groups, one including three well-resolved lineages and the other comprising a four-lineage polytomy and a well-differentiated sister taxon. Integrative species delimitation analyses indicated that the number of employed loci had little impact on the obtained inferences but revealed the higher power provided by an increasing number of phenotypic characters and the usefulness of assessing their phylogenetic information content and differences between sexes in among-taxa trait variation. Overall, our study highlights the importance of integrating multiple sources of information to test competing phylogenetic hypotheses and elucidate the evolutionary history of species complexes representing early stages of divergence where conflicting inferences are more prone to appear.


Assuntos
Evolução Biológica , Genoma , Gafanhotos/genética , Fenótipo , Animais , Análise por Conglomerados , Biologia Computacional , Genótipo , Gafanhotos/anatomia & histologia , Gafanhotos/classificação , Filogenia , Especificidade da Espécie
14.
Mol Phylogenet Evol ; 118: 343-356, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29080673

RESUMO

Understanding the consequences of past environmental changes on the abiotic and biotic components of the landscape and deciphering their impacts on the demographic trajectories of species is a major issue in evolutionary biogeography. In this study, we combine nuclear and mitochondrial genetic data to study the phylogeographical structure and lineage-specific demographic histories of the scrub-legume grasshopper (Chorthippus binotatus binotatus), a montane taxon distributed in the Iberian Peninsula and France that exclusively feeds on certain scrub-legume species. Genetic data and paleo-distribution modelling indicate the presence of four main lineages that seem to have diverged in allopatry and long-term persisted in Iberian and French refugia since the Mid Pleistocene. Comparisons of different demographic hypotheses in an Approximate Bayesian Computation (ABC) framework supported a population bottleneck in the northwestern French clade and paleo-distribution modelling indicate that the populations of this lineage have experienced more severe environmental fluctuations during the last 21 000 years than those from the Iberian Peninsula. Accordingly, we found that nuclear genetic diversity of the populations of scrub-legume grasshopper is positively associated with local stability of suitable habitats defined by both Pleistocene climate changes and historical distributional shifts of host-plant species. Overall, our study highlights the importance of integrating the potential effects of abiotic (i.e. climate and geography) and biotic components (i.e. inter-specific interactions) into the study of the evolutionary and demographic history of specialist taxa with narrow ecological requirements.


Assuntos
Variação Genética , Gafanhotos/genética , Animais , Teorema de Bayes , Mudança Climática , DNA/isolamento & purificação , DNA/metabolismo , Ecossistema , Complexo IV da Cadeia de Transporte de Elétrons/química , Complexo IV da Cadeia de Transporte de Elétrons/genética , França , Genética Populacional , Gafanhotos/classificação , Desequilíbrio de Ligação , Filogenia , Filogeografia
15.
J Allergy Clin Immunol ; 141(4): 1365-1372, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29074457

RESUMO

BACKGROUND: Numerous dietary restrictions and endoscopies limit the implementation of empiric elimination diets in patients with eosinophilic esophagitis (EoE). Milk and wheat/gluten are the most common food triggers. OBJECTIVE: We sought to assess the effectiveness of a step-up dietary strategy for EoE. METHODS: We performed a prospective study conducted in 14 centers. Patients underwent a 6-week 2-food-group elimination diet (TFGED; milk and gluten-containing cereals). Remission was defined by symptom improvement and less than 15 eosinophils/high-power field. Nonresponders were gradually offered a 4-food-group elimination diet (FFGED; TFGED plus egg and legumes) and a 6-food-group elimination diet (SFGED; FFGED plus nuts and fish/seafood). In responders eliminated food groups were reintroduced individually, followed by endoscopy. RESULTS: One hundred thirty patients (25 pediatric patients) were enrolled, with 97 completing all phases of the study. A TFGED achieved EoE remission in 56 (43%) patients, with no differences between ages. Food triggers in TFGED responders were milk (52%), gluten-containing grains (16%), and both (28%). EoE induced only by milk was present in 18% and 33% of adults and children, respectively. Remission rates with FFGEDs and SFGEDs were 60% and 79%, with increasing food triggers, especially after an SFGED. Overall, 55 (91.6%) of 60 of the TFGED/FFGED responders had 1 or 2 food triggers. Compared with the initial SFGED, a step-up strategy reduced endoscopic procedures and diagnostic process time by 20%. CONCLUSIONS: A TFGED diet achieves EoE remission in 43% of children and adults. A step-up approach results in early identification of a majority of responders to an empiric diet with few food triggers, avoiding unnecessary dietary restrictions, saving endoscopies, and shortening the diagnostic process.


Assuntos
Esofagite Eosinofílica/dietoterapia , Hipersensibilidade Alimentar/dietoterapia , Adulto , Esofagite Eosinofílica/diagnóstico , Esofagite Eosinofílica/etiologia , Feminino , Hipersensibilidade Alimentar/complicações , Hipersensibilidade Alimentar/diagnóstico , Humanos , Masculino , Estudos Prospectivos , Fatores de Risco , Resultado do Tratamento
18.
BMC Evol Biol ; 17(1): 109, 2017 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-28472922

RESUMO

BACKGROUND: The combination of model-based comparative techniques, disparity analyses and ecomorphological correlations constitutes a powerful method to gain insight into the evolutionary mechanisms that shape morphological variation and speciation processes. In this study, we used a time-calibrated phylogeny of 70 Iberian species of short-horned grasshoppers (Acrididae) to test for patterns of morphological disparity in relation to their ecology and phylogenetic history. Specifically, we examined the role of substrate type and level of ecological specialization in driving different aspects of morphological evolution (locomotory traits, chemosensitive organs and cranial morphology) in this recent radiation. RESULTS: We found a bimodal distribution of locomotory attributes corresponding to the two main substrate type guilds (plant vs. ground); plant-perching species tend to exhibit larger wings and thicker femora than those that remain on the ground. This suggests that life form (i.e., substrate type) is an important driving force in the evolution of morphological traits in short-horned grasshoppers, irrespective of ancestry. Substrate type and ecological specialization had no significant influence on head shape, a trait that showed a strong phylogenetic conservatism. Finally, we also found a marginal significant association between the length of antennae and the level of ecological specialization, suggesting that the development of sensory organs may be favored in specialist species. CONCLUSIONS: Our results provide evidence that even in taxonomic groups showing limited morphological and ecological disparity, natural selection seems to play a more important role than genetic drift in driving the speciation process. Overall, this study suggests that morphostatic radiations should not necessarily be considered as "non-adaptive" and that the speciation process can bind both adaptive divergence mechanisms and neutral speciation processes related with allopatric and/or reproductive isolation.


Assuntos
Gafanhotos/anatomia & histologia , Gafanhotos/classificação , Animais , Antenas de Artrópodes/anatomia & histologia , Evolução Biológica , Ecologia , Feminino , Especiação Genética , Gafanhotos/genética , Masculino , Filogenia , Crânio/anatomia & histologia
19.
Ecol Evol ; 7(9): 3110-3122, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28480010

RESUMO

Understanding the processes underlying spatial patterns of genetic diversity and structure of natural populations is a central topic in evolutionary biogeography. In this study, we combine data on ancient and contemporary landscape composition to get a comprehensive view of the factors shaping genetic variation across the populations of the scrub-legume grasshopper (Chorthippus binotatus binotatus) from the biogeographically complex region of southeast Iberia. First, we examined geographical patterns of genetic structure and employed an approximate Bayesian computation (ABC) approach to compare different plausible scenarios of population divergence. Second, we used a landscape genetic framework to test for the effects of (1) Late Miocene paleogeography, (2) Pleistocene climate fluctuations, and (3) contemporary topographic complexity on the spatial patterns of population genetic differentiation. Genetic structure and ABC analyses supported the presence of three genetic clusters and a sequential west-to-east splitting model that predated the last glacial maximum (LGM, c. 21 Kya). Landscape genetic analyses revealed that population genetic differentiation was primarily shaped by contemporary topographic complexity, but was not explained by any paleogeographic scenario or resistance distances based on climate suitability in the present or during the LGM. Overall, this study emphasizes the need of integrating information on ancient and contemporary landscape composition to get a comprehensive view of their relative importance to explain spatial patterns of genetic variation in organisms inhabiting regions with complex biogeographical histories.

20.
Curr Opin Gastroenterol ; 33(4): 285-292, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28445189

RESUMO

PURPOSE OF REVIEW: To update rapidly evolving concepts regarding the controversial entity of 'proton pump inhibitor (PPI)-responsive esophageal eosinophilia,' referring to patients with clinical, endoscopic and histologic features of eosinophilic esophagitis (EoE) who achieve remission on PPI therapy. RECENT FINDINGS: Up to half of pediatric and adult patients with typical EoE symptoms and histology achieve clinico-pathologic remission on PPI therapy, irrespective of whether esophageal pH monitoring demonstrates abnormal acid reflux. In patients with clinical and histologic features of EoE, genotypic and phenotypic features of PPI responders and nonresponders are virtually indistinguishable, and different from those of patients with gastroesophageal reflux disease. In PPI responders, PPIs effects on esophageal Th2 inflammation and gene expression are similar to those of topical steroids in PPI nonresponders. These therapies, along with diets, recently have been shown to be potentially interchangeable in two small series. SUMMARY: Proton pump inhibitor-responsive esophageal eosinophilia is an inappropriate disease descriptor, arbitrarily based on a response to a single drug, and should be abandoned. Patients who have esophageal eosinophilia and esophageal symptoms that resolve with PPI therapy have phenotypic, molecular, mechanistic, and therapeutic features indistinguishable from similar patients who do not respond to PPIs. These patients with PPI responsiveness should be considered within the spectrum of EoE.


Assuntos
Esofagite Eosinofílica/diagnóstico , Refluxo Gastroesofágico/diagnóstico , Inibidores da Bomba de Prótons/uso terapêutico , Diagnóstico Diferencial , Esofagite Eosinofílica/tratamento farmacológico , Esofagite Eosinofílica/imunologia , Monitoramento do pH Esofágico , Refluxo Gastroesofágico/tratamento farmacológico , Refluxo Gastroesofágico/imunologia , Guias como Assunto , Humanos , Indução de Remissão , Células Th2/efeitos dos fármacos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA