RESUMO
Patterns of species diversity have been associated with changes in climate across latitude and elevation. However, the ecological and evolutionary mechanisms underlying these relationships are still actively debated. Here, we present a complementary view of the well-known tropical niche conservatism (TNC) hypothesis, termed the multiple zones of origin (MZO) hypothesis, to explore mechanisms underlying latitudinal and elevational gradients of phylogenetic diversity in tree communities. The TNC hypothesis posits that most lineages originate in warmer, wetter, and less seasonal environments in the tropics and rarely colonize colder, drier, and more seasonal environments outside of the tropical lowlands, leading to higher phylogenetic diversity at lower latitudes and elevations. In contrast, the MZO hypothesis posits that lineages also originate in temperate environments and readily colonize similar environments in the tropical highlands, leading to lower phylogenetic diversity at lower latitudes and elevations. We tested these phylogenetic predictions using a combination of computer simulations and empirical analyses of tree communities in 245 forest plots located in six countries across the tropical and subtropical Andes. We estimated the phylogenetic diversity for each plot and regressed it against elevation and latitude. Our simulated and empirical results provide strong support for the MZO hypothesis. Phylogenetic diversity among co-occurring tree species increased with both latitude and elevation, suggesting an important influence on the historical dispersal of lineages with temperate origins into the tropical highlands. The mixing of different floras was likely favored by the formation of climatically suitable corridors for plant migration due to the Andean uplift. Accounting for the evolutionary history of plant communities helps to advance our knowledge of the drivers of tree community assembly along complex climatic gradients, and thus their likely responses to modern anthropogenic climate change.
RESUMO
Torque teno sus virus (TTSuV) infection is common worldwide in both healthy and diseased swine and a relationship between this virus and a particular disease in pigs has not been established. This work aimed to investigate the presence of TTSuV1 and TTSuVk2a in Porcine Circovirus type 2 (PCV2)-infected and non-infected domestic pigs and free-living wild boars from Uruguay. Our data evidenced a high frequency of detection and a wide circulation of TTSuV among pig herds and wild boar populations. Furthermore, TTSuV1+TTSuVk2a co-infection was more frequent than single infections in domestic pigs. In addition, we thoroughly characterized at the molecular level TTSuV strains by extensive sequence data analysis. Our findings revealed an extremely high genetic heterogeneity among Uruguayan isolates. On the basis of detailed analyses, we proposed a more comprehensive criterion of TTSuV classification which would contribute to shedding light over the genetic diversity of these viruses worldwide. On the other hand, data obtained suggested that neither TTSuV1 nor TTSuVk2a frequency of infection or viral loads have any correlation with PCV2 infection, health status or age. The role of TTSuV during co-infection with other pathogens and the age-related dynamics of TTSuV infection are currently under debate. Therefore, taking into account the controversial epidemiological data regarding these viruses and their ubiquitous infection, a likely role as components of the host microbiota should be brought into discussion.
Assuntos
Infecções por Circoviridae/veterinária , Circovirus/genética , Coinfecção/veterinária , Infecções por Vírus de DNA/veterinária , Heterogeneidade Genética , Doenças dos Suínos/epidemiologia , Torque teno virus/genética , Animais , Infecções por Circoviridae/epidemiologia , Infecções por Circoviridae/virologia , Coinfecção/epidemiologia , Coinfecção/virologia , Infecções por Vírus de DNA/epidemiologia , Infecções por Vírus de DNA/virologia , DNA Viral/genética , Filogenia , Sus scrofa/virologia , Suínos/virologia , Doenças dos Suínos/virologia , Torque teno virus/isolamento & purificação , Uruguai/epidemiologia , Carga ViralRESUMO
Hepatitis E virus (HEV) infection involving zoonotic genotypes is a public health problem in high-income and non-endemic developing countries. Herein we report the detection of a human genotype 1 (HEV-1) strain infecting a domestic pig, which is not considered a natural reservoir of this genotype. Viral load was quantified in stool by Real-Time qPCR and sequence analyses were performed. Infectivity of the HEV-1 strain was assesed by in vitro isolation in A549 cell line. Results suggest that certain epidemiological settings might favour accidental spillover infection and thus influence the host range restriction of HEV.
Assuntos
Vírus da Hepatite E/isolamento & purificação , Hepatite E/veterinária , Hepatite E/virologia , Doenças dos Suínos/virologia , Animais , Fezes/virologia , Anticorpos Anti-Hepatite , Hepatite E/imunologia , Vírus da Hepatite E/classificação , Vírus da Hepatite E/genética , Vírus da Hepatite E/imunologia , Humanos , Filogenia , Sus scrofa/imunologia , Sus scrofa/virologia , Suínos , Doenças dos Suínos/imunologiaRESUMO
Porcine Circovirus type 2 (PCV2) is a worldwide distributed pathogen and one of the most economically relevant swine infections. Four genotypes have been recognized and it is well known that PCV2a, PCV2b and PCV2d have a global distribution. However, the information about recombinant strains circulation and their influence in driving PCV2 evolution is a poorly studied area. In Uruguay, PCV2 associated symptoms began to be frequently observed in pigs from different farms since 2010. The main purpose of this study was to thoroughly investigate the molecular epidemiology of PCV2 in nationwide swine herds and free-living wild boars during the period 2010-2014, providing an extensive viral sequence dataset. Surprisingly, the findings revealed a predominance of recombinant strains circulation, evidencing for the first time in the field that PCV2 recombination can lead to the emergence of strains able to compete and potentially displace parental ones. In addition, the circulation of the genotypes PCV2d (29%), PCV2b (10.5%) and PCV2a (7.9%) were also observed. Since 2013, a high circulation of PCV2d was identified in the country and probably reflected the recent global scenario of the emergence of this genotype. In addition, fluctuations in the frequency of PCV2 infection in the period evaluated may suggest a limitation of biosecurity strategies implemented in Uruguay for the disease control, including the instability of vaccination practices. On the other hand, the sustained PCV2 infection observed in wild boar population and the similarity among circulating viral strains from these animals and domestic pigs, suggested that wild animals could serve as permanent reservoir of the disease. Altogether, this work put forward that many factors play a role in PCV2 heterogeneity including rapid viral spread and evolution, recombination, wide movement within national boundaries and multiples introduction events resulting of international trade. Continuous monitoring of viral epidemiology is needed to better understand the PCV2 population dynamics in Uruguay and the development of appropriate strategies are required for disease control.
Assuntos
Proteínas do Capsídeo/genética , Infecções por Circoviridae/epidemiologia , Circovirus/genética , Sus scrofa/genética , Doenças dos Suínos/epidemiologia , Suínos/genética , Animais , Infecções por Circoviridae/diagnóstico , Infecções por Circoviridae/genética , Infecções por Circoviridae/virologia , Circovirus/classificação , DNA Viral/genética , Genoma , Genótipo , Epidemiologia Molecular , Filogenia , Recombinação Genética , Análise de Sequência de DNA , Sus scrofa/virologia , Suínos/virologia , Doenças dos Suínos/diagnóstico , Doenças dos Suínos/genética , Doenças dos Suínos/virologia , Fatores de Tempo , Uruguai/epidemiologiaRESUMO
General patterns of forest dynamics and productivity in the Andes Mountains are poorly characterized. Here we present the first large-scale study of Andean forest dynamics using a set of 63 permanent forest plots assembled over the past two decades. In the North-Central Andes tree turnover (mortality and recruitment) and tree growth declined with increasing elevation and decreasing temperature. In addition, basal area increased in Lower Montane Moist Forests but did not change in Higher Montane Humid Forests. However, at higher elevations the lack of net basal area change and excess of mortality over recruitment suggests negative environmental impacts. In North-Western Argentina, forest dynamics appear to be influenced by land use history in addition to environmental variation. Taken together, our results indicate that combinations of abiotic and biotic factors that vary across elevation gradients are important determinants of tree turnover and productivity in the Andes. More extensive and longer-term monitoring and analyses of forest dynamics in permanent plots will be necessary to understand how demographic processes and woody biomass are responding to changing environmental conditions along elevation gradients through this century.
Assuntos
Florestas , Biodiversidade , Modelos Lineares , Análise de Componente Principal , Árvores/crescimento & desenvolvimentoRESUMO
BACKGROUND: Adjustable gastric banding (AGB) and vertical banded gastroplasty (VBG) have been extensively used to treat morbid obesity. Patients with insufficient weight loss or complications may require surgical revision. The laparoscopic Roux-en-Y gastric bypass (LRYGBP) is one of the most common procedures currently used for revision. The aim of the study was to analyze surgical outcomes of 30 consecutive patients who underwent revision to LRYGBP in a 2-year period. METHODS: The prospectively constructed database and the medical records of all patients undergoing revision to LRYGBP were reviewed. Demographics, surgical details, results, and complications were analyzed. RESULTS: There were 23 women and seven men with a mean age of 41.1+/-9.7 years (r=25-61). Mean body mass index (BMI) was 40.0+/-7.5 kg/m(2) (r=27.2-65.2). Initial operation was AGB in 24, VBG in five, and both in one patient. In ten patients, the band had been removed before revision, in 13 cases, band removal and LRYGBP were performed in one surgical intervention, and in two patients, it was performed in a two-step surgery. There were two conversions to open surgery. Five patients presented major surgical complications. Hospital stay averaged 5.1 days (r=3-25). Mean percent excess body weight loss at 6 and 12 months was 61.7+/-27.5 and 81.2+/-20.5 kg/m(2), respectively. Mean percent low body mass index at 6 and 12 months was 22.5+/-9.1 and 29.1+/-11.4 kg/m(2), respectively. CONCLUSIONS: LRYGBP as a revision procedure is feasible in most patients. Surgical complications are more frequent.