Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 97
Filtrar
Mais filtros

Bases de dados
Tipo de documento
Intervalo de ano de publicação
1.
Mol Phylogenet Evol ; 184: 107785, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37085130

RESUMO

Marmots (Marmota spp.) comprise a lineage of large-bodied ground squirrels that diversified rapidly in the Pleistocene, when the planet quickly transitioned to a drier, colder, and highly seasonal climate-particularly at high latitudes. Fossil evidence indicates the genus spread from North America, across Beringia, and into the European Alps over the course of only a few million years, beginning in the late Pliocene. Marmots are highly adapted to survive long and severely cold winters, and this likely favored their expansion and diversification over this time period. Previous phylogenetic studies have identified two major subgenera of marmots, but the timing of important speciation events and some species relationships have been difficult to resolve. Here we use ultraconserved elements and mitogenomes, with samples from all 15 extant species, to more precisely retrace how and when marmots came to inhabit a vast Holarctic range. Our results indicate marmots arose in North America in the Early Miocene (∼16.3 Ma) and dispersed across the Bering Land Bridge in the Pliocene (∼3-4 Ma); in addition, our fossil-calibrated timeline is suggestive of the rise and spread of open grasslands as being particularly important to marmot diversification. The woodchuck (M. monax) and the Alaska marmot (M. broweri) are found to be more closely related to the Eurasian species than to the other North American species. Paraphyly is evident in the bobak marmot (M. bobak) and the hoary marmot (M. caligata), and in the case of the latter the data are highly suggestive of a second, cryptic species in the Cascade Mountains of Washington.


Assuntos
Marmota , Sciuridae , Animais , Filogenia , Clima , Adaptação Fisiológica
2.
Mol Ecol ; 29(9): 1717-1729, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32270561

RESUMO

Madagascar's shrew tenrecs (Mammalia: Tenrecidae; Microgale, Nesogale) represent an excellent system for studying speciation. Most species are endemic to the island's eastern humid forests, a region renowned for high levels of biodiversity and a high rate of in situ diversification. We set out to understand the speciation dynamics in a clade of recently described taxa: Microgale fotsifotsy and M. soricoides, which have nearly identical distributions in the moist evergreen forest, and M. nasoloi, which occurs in the western dry deciduous forest. A phylogenetic analysis using mitochondrial DNA data recovered two distinct clades of M. fotsifotsy: a south clade that is sister to, and broadly sympatric with, M. soricoides, and a north clade that is sister to the dry-forest and distantly allopatric species M. nasoloi. To better understand this result, we analysed cranioskeletal measurements and performed demographic analyses using nuclear sequence data from ultraconserved elements. Nuclear data did not support a sister relationship between M. soricoides and the south clade of M. fotsifotsy but did demonstrate introgression between these clades, which probably explains the discordance between nuclear and mitochondrial phylogenies. Demographic analyses also revealed the absence of gene flow between the north and south clades of M. fotsifotsy. Morphometric data revealed several major differences between M. soricoides and M. fotsifotsy, as well as more subtle differences between the two clades of M. fotsifotsy. In light of these results, we treat the south clade of M. fotsifotsy as a new candidate species. Our findings demonstrate the utility of integrating multiple data types to understand complex speciation histories, and contribute to a growing body of evidence that species diversity on Madagascar is underestimated.


Assuntos
Eutérios/genética , Fluxo Gênico , Especiação Genética , Simpatria , Animais , DNA Mitocondrial/genética , Eutérios/classificação , Madagáscar , Filogenia
3.
Dis Esophagus ; 32(7)2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30855088

RESUMO

Oral contrast studies are used to detect anastomotic leak (AL) postesophagectomy. However, recent evidence suggests oral contrast studies have low sensitivity in detecting ALs, and their false positive results can lead to unnecessary prolonged hospital stay. The objective of this study was to determine if oral contrast studies should be used routinely post-esophagectomy for cancer. A systematic literature search was conducted for studies published between January 1990 and June 2018. Data extracted for analyses included type of esophagectomy, operative morbidity (such as AL and pneumonia), mortality rates, timing of contrast study, and type of oral contrast used. The sensitivity, specificity, and positive and negative predictive values of routine oral contrast studies to detect AL were calculated using the aforementioned variables. Two hundred and forty-seven studies were reviewed with 16 studies included in the meta-analysis. Postoperative oral contrast study was performed in 94.0% of cases between day 5 and 7. The rates of early and delayed leaks were 2.4% (1.8%-3.3%) and 2.8% (1.8%-4.4%), respectively. Routine contrast studies have a sensitivity and specificity of 0.44 (0.32-0.57) and 0.98 (0.95-0.99), respectively. Analysis of covariates revealed that sensitivity is reduced in centers with a higher volume of cases (greater than 15 per year: 0.50 [0.34-0.75; p = 0.0008]) and specificity was higher in centers with a lower leak rate. Given its poor sensitivity and inability to detect early/delayed AL, oral contrast study should be used selectively with endoscopy and/or computerized tomography scan to assess surgical anastomoses following esophagectomy.


Assuntos
Fístula Anastomótica/diagnóstico por imagem , Administração Oral , Fístula Anastomótica/etiologia , Meios de Contraste/administração & dosagem , Esofagectomia/efeitos adversos , Humanos , Valor Preditivo dos Testes , Radiografia/métodos
4.
Mol Phylogenet Evol ; 126: 74-84, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29501374

RESUMO

Madagascar is one of the world's foremost biodiversity hotspots, yet a large portion of its flora and fauna remains undescribed and the driving forces of in situ diversification are not well understood. Recent studies have identified a widespread, latitudinally structured phylogeographic pattern in Madagascar's humid-forest mammals, amphibians, reptiles, and insects. Several factors may be driving this pattern, namely biogeographic barriers (i.e., rivers or valleys) or past episodes of forest contraction and expansion. In this study, we describe the phylogeographic structure of the small, semifossorial mammal Oryzorictes hova, one of Madagascar's two species of mole tenrec, found throughout Madagascar's eastern humid forest belt, from high-elevation montane forest to low-elevation forests, as well as disturbed habitat such as rice fields. Using one mitochondrial locus, four nuclear loci, and 31 craniomandibular measurements, we identified three distinct populations of O. hova associated with the northern, central, and southern regions of the island. We found little evidence of gene flow among these populations, so we treated each population as a potential species. We validated species limits using two Bayesian methods: BP&P, employing only DNA sequence data, and iBPP using both DNA and morphological data, and we assessed whether these methods are susceptible to producing false positive errors. Molecular and morphological data support the recognition of each of the three populations of O. hova as distinct species, but formal species descriptions will require additional data from type specimens. This study illustrates the importance of using integrative datasets, multiple methodological approaches, and extensive geographic sampling for species delimitation and adds evidence for a widespread phylogeographic pattern in Madagascar's humid forest taxa.


Assuntos
Altitude , Especiação Genética , Mamíferos/genética , Animais , Teorema de Bayes , Biodiversidade , Genética Populacional , Haplótipos/genética , Madagáscar , Filogenia , Filogeografia , Análise de Componente Principal , Especificidade da Espécie , Fatores de Tempo
5.
Clin Infect Dis ; 64(12): 1737-1741, 2017 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-28329402

RESUMO

BACKGROUND.: Human infection by orthopoxviruses is being reported with increasing frequency, attributed in part to the cessation of smallpox vaccination and concomitant waning of population-level immunity. In July 2015, a female resident of interior Alaska presented to an urgent care clinic with a dermal lesion consistent with poxvirus infection. Laboratory testing of a virus isolated from the lesion confirmed infection by an Orthopoxvirus. METHODS.: The virus isolate was characterized by using electron microscopy and nucleic acid sequencing. An epidemiologic investigation that included patient interviews, contact tracing, and serum testing, as well as environmental and small-mammal sampling, was conducted to identify the infection source and possible additional cases. RESULTS.: Neither signs of active infection nor evidence of recent prior infection were observed in any of the 4 patient contacts identified. The patient's infection source was not definitively identified. Potential routes of exposure included imported fomites from Azerbaijan via the patient's cohabiting partner or wild small mammals in or around the patient's residence. Phylogenetic analyses demonstrated that the virus represents a distinct and previously undescribed genetic lineage of Orthopoxvirus, which is most closely related to the Old World orthopoxviruses. CONCLUSIONS.: Investigation findings point to infection of the patient after exposure in or near Fairbanks. This conclusion raises questions about the geographic origins (Old World vs North American) of the genus Orthopoxvirus. Clinicians should remain vigilant for signs of poxvirus infection and alert public health officials when cases are suspected.


Assuntos
Orthopoxvirus/isolamento & purificação , Infecções por Poxviridae/diagnóstico , Infecções por Poxviridae/virologia , Alaska , Animais , Anticorpos Antivirais/sangue , DNA Viral/sangue , Feminino , Fômites/virologia , Humanos , Mamíferos/virologia , Microscopia Eletrônica , Pessoa de Meia-Idade , Orthopoxvirus/classificação , Orthopoxvirus/genética , Orthopoxvirus/ultraestrutura , Filogenia , Análise de Sequência de DNA , Pele/patologia , Pele/virologia
6.
Mol Phylogenet Evol ; 113: 150-160, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28552433

RESUMO

Giant sengis (Macroscelidea; Macroscelididae; Rhynchocyon), also known as giant elephant-shrews, are small-bodied mammals that range from central through eastern Africa. Previous research on giant sengi systematics has relied primarily on pelage color and geographic distribution. Because some species have complex phenotypic variation and large geographic ranges, we used molecular markers to evaluate the phylogeny and taxonomy of the genus, which currently includes four species: R. chrysopygus, R. cirnei (six subspecies), R. petersi (two subspecies), and R. udzungwensis. We extracted DNA from fresh and historical museum samples from all taxa except one R. cirnei subspecies, and we generated and analyzed approximately 4700 aligned nucleotides (2685 bases of mitochondrial DNA and 2019 bases of nuclear DNA) to reconstruct a molecular phylogeny. We genetically evaluate Rhynchocyon spp. sequences previously published on GenBank, propose that the captive R. petersi population in North American zoos is likely R. p. adersi, and suggest that hybridization among taxa is not widespread in Rhynchocyon. The DNA sample we have from the distinctive but undescribed giant sengi from the Boni forest of northern coastal Kenya is unexpectedly nearly identical to R. chrysopygus, which will require further study. Our analyses support the current morphology-based taxonomy, with each recognized species forming a monophyletic clade, but we propose elevating R. c. stuhlmanni to a full species.


Assuntos
Filogenia , Musaranhos/classificação , Musaranhos/genética , Alelos , Animais , Sequência de Bases , Teorema de Bayes , DNA Mitocondrial/genética , Geografia , Quênia , Pigmentação , Especificidade da Espécie
7.
Syst Biol ; 65(5): 890-909, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27103169

RESUMO

The family Tenrecidae (tenrecs) is one of only four extant terrestrial mammal lineages to have colonized and diversified on Madagascar. Over the last 15 years, several studies have disagreed on relationships among major tenrec lineages, resulting in multiple reinterpretations of the number and timing of historical transoceanic dispersal events between Africa and Madagascar. We reconstructed the phylogeny of Tenrecidae using multiple loci from all recognized extant species and estimated divergence timing using six fossil calibrations within Afrotheria. All phylogenetic analyses strongly support monophyly of the Malagasy tenrecs, and our divergence timing analysis places their colonization of the island at 30-56 Ma. Our comprehensive phylogeny supports three important taxonomic revisions that reflect the evolutionary history of tenrecs: (1) we formally elevate the African otter shrews to their own family Potamogalidae, thereby rendering extant Tenrecidae entirely endemic to Madagascar; (2) we subsume the semiaquatic genus Limnogale within the shrew tenrec genus Microgale; and (3) we re-elevate the two largest-bodied shrew tenrecs, Microgale dobsoni and Microgale talazaci, to the genus Nesogale Thomas (1918) Finally, we use recently summarized habitat data to test the hypothesis that diversification rates differ between humid and arid habitats on Madagascar, and we compare three common methods for ancestral biogeographic reconstruction. These analyses suggest higher speciation rates in humid habitats and reveal a minimum of three and more likely five independent transitions to arid habitats. Our results resolve the relationships among previously recalcitrant taxa, illuminate the timing and mechanisms of major biogeographic patterns in an extraordinary example of an island radiation, and permit the first comprehensive, phylogenetically consistent taxonomy of Madagascar's tenrecs.


Assuntos
Filogenia , Musaranhos/classificação , Musaranhos/genética , África , Animais , Ecossistema , Florestas , Especiação Genética , Madagáscar , Fatores de Tempo
8.
Allergy ; 71(2): 210-9, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26465137

RESUMO

BACKGROUND: Data on the long-term impact of hydrolyzed formulas on allergies are scarce. OBJECTIVE: To assess the association between early intervention with hydrolyzed formulas in high-risk children and allergic outcomes in adolescence. METHODS: GINI trial participants (n = 2252) received one of four formulas in the first four months of life as breastmilk substitute if necessary: partial or extensive whey hydrolyzate (pHF-W, eHF-W), extensive casein hydrolyzate (eHF-C) or standard cow's milk formula (CMF) as reference. Associations between these formulas and the cumulative incidence and prevalence of parent-reported physician-diagnosed asthma, allergic rhinitis (AR) and eczema, as well as spirometric indices and sensitization, were examined using generalized linear models. RESULTS: Between 11 and 15 years, the prevalence of asthma was reduced in the eHF-C group compared to CMF (odds ratio (OR) 0.49, 95% confidence interval (CI) 0.26-0.89), which is consistent with the spirometric results. The cumulative incidence of AR was lower in eHF-C (risk ratio (RR) 0.77, 95% CI 0.59-0.99]) and the AR prevalence in pHF-W (OR 0.67, 95% CI 0.47-0.95) and eHF-C (OR 0.59, 95% CI 0.41-0.84). The cumulative incidence of eczema was reduced in pHF-W (RR 0.75, 95% CI 0.59-0.96) and eHF-C (RR 0.60, 95% CI 0.46-0.77), as was the eczema prevalence between 11 and 15 years in eHF-C (OR 0.42, 95% CI 0.23-0.79). No significant effects were found in the eHF-W group on any manifestation,nor was there an effect on sensitization with any formula. CONCLUSION: In high-risk children, early intervention using different hydrolyzed formulas has variable preventative effects on asthma, allergic rhinitis and eczema up to adolescence.


Assuntos
Hipersensibilidade/epidemiologia , Hipersensibilidade/prevenção & controle , Fórmulas Infantis , Adolescente , Animais , Bovinos , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Hipersensibilidade/diagnóstico , Hipersensibilidade/etiologia , Incidência , Lactente , Recém-Nascido , Masculino , Leite , Proteínas do Leite , Razão de Chances , Avaliação de Resultados da Assistência ao Paciente , Prevalência , Espirometria
9.
Mol Ecol ; 24(14): 3688-705, 2015 07.
Artigo em Inglês | MEDLINE | ID: mdl-26096099

RESUMO

Identifying the genetic structure of a species and the factors that drive it is an important first step in modern population management, in part because populations evolving from separate ancestral sources may possess potentially different characteristics. This is especially true for climate-sensitive species such as pikas, where the delimitation of distinct genetic units and the characterization of population responses to contemporary and historical environmental pressures are of particular interest. We combined a restriction site-associated DNA sequencing (RADSeq) data set containing 4156 single nucleotide polymorphisms with ecological niche models (ENMs) of present and past habitat suitability to characterize population composition and evaluate the effects of historical range shifts, contemporary climates and landscape factors on gene flow in Collared Pikas, which are found in Alaska and adjacent regions of northwestern Canada and are the lesser-studied of North America's two pika species. The results suggest that contemporary environmental factors contribute little to current population connectivity. Instead, genetic diversity is strongly shaped by the presence of three ancestral lineages isolated during the Pleistocene (~148 and 52 kya). Based on ENMs and genetic data, populations originating from a northern refugium experienced longer-term stability, whereas both southern lineages underwent population expansion - contradicting the southern stability and northern expansion patterns seen in many other taxa. Current populations are comparable with respect to generally low diversity within populations and little-to-no recent admixture. The predominance of divergent histories structuring populations implies that if we are to understand and manage pika populations, we must specifically assess and accurately account for the forces underlying genetic similarity.


Assuntos
Evolução Biológica , Fluxo Gênico , Genética Populacional , Lagomorpha/genética , Alaska , Animais , Canadá , Ecossistema , Funções Verossimilhança , Modelos Genéticos , Filogeografia , Polimorfismo de Nucleotídeo Único , Densidade Demográfica , Análise de Sequência de DNA
10.
Acta Anaesthesiol Scand ; 58(3): 281-90, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24383612

RESUMO

BACKGROUND: Recent interest has focused on the role of perioperative epidural analgesia in improving cancer outcomes. The heterogeneity of studies (tumour type, stage and outcome endpoints) has produced inconsistent results. Clinical practice also highlights the variability in epidural effectiveness. We considered the novel hypothesis that effective epidural analgesia improves cancer outcomes following gastro-oesophageal cancer surgery in patients with grouped pathological staging. METHODS: Following institutional approval, a database analysis identified 140 patients, with 2-year minimum follow-up after gastro-oesophageal cancer surgery. All patients were operated on by a single surgeon (2005-2010). Information pertaining to cancer and survival outcomes was extracted. RESULTS: Univariate analysis demonstrated a 1-year 14% vs. 33% (P = 0.01) and 2-year 27% vs. 40% [hazard ratio (HR)=0.59; 95% CI, 0.32-1.09, P = 0.087] incidence of cancer recurrence in patients with (vs. without) effective (> 36 h duration) epidural analgesia, respectively. Multivariate analysis demonstrated increased time to cancer recurrence (HR = 0.33; 95% CI: 0.17-0.63, P < 0.0001) and overall survival benefit (HR = 0.42; 95% CI: 0.21-0.83, P < 0.0001) at 2-year follow-up following effective epidural analgesia. Subgroup analysis identified epidural-related cancer recurrence benefit in patients with oesophageal cancer (HR = 0.34; 95% CI: 0.16-0.75, P = 0.005) and in patients with tumour lymphovascular space infiltration (LVSI), (HR = 0.49; 95% CI: 0.26-0.94, P = 0.03). Effective epidural analgesia improved estimated median time to death (2.9 vs. 1.8 years, P = 0.029) in patients with tumour LVSI. CONCLUSIONS: This study found an association between effective post-operative epidural analgesia and medium-term benefit on cancer recurrence and survival following oesophageal surgery. A prospective study that controls for disease type, stage and epidural effectiveness is warranted.


Assuntos
Analgesia Epidural , Neoplasias Esofágicas/prevenção & controle , Neoplasias Esofágicas/cirurgia , Recidiva Local de Neoplasia/prevenção & controle , Neoplasias Gástricas/prevenção & controle , Neoplasias Gástricas/cirurgia , Idoso , Neoplasias Esofágicas/epidemiologia , Esôfago/patologia , Esôfago/cirurgia , Feminino , Seguimentos , Gastrectomia , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Estômago/patologia , Neoplasias Gástricas/epidemiologia , Análise de Sobrevida
11.
PLoS One ; 19(5): e0294376, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38739612

RESUMO

Understanding and mitigating the effects of anthropogenic climate change on species distributions requires the ability to track range shifts over time. This is particularly true for species occupying high-latitude regions, which are experiencing more extreme climate change than the rest of the world. In North America, the geographic ranges of many mammals reach their northernmost extent in Alaska, positioning this region at the leading edge of climate-induced distribution change. Over a decade has elapsed since the publication of the last spatial assessments of terrestrial mammals in the state. We compared public occurrence records against commonly referenced range maps to evaluate potential extralimital records and develop repeatable baseline range maps. We compared occurrence records from the Global Biodiversity Information Facility for 61 terrestrial mammal species native to mainland Alaska against a variety of range estimates (International Union for Conservation of Nature, Alaska Gap Analysis Project, and the published literature). We mapped extralimital records and calculated proportions of occurrences encompassed by range extents, measured mean direction and distance to prior range margins, evaluated predictive accuracy of published species models, and highlighted observations on federal lands in Alaska. Range comparisons identified 6,848 extralimital records for 39 of 61 (63.9%) terrestrial mainland Alaskan species. On average, 95.5% of Alaska Gap Analysis Project occurrence records and ranges were deemed accurate (i.e., > 90.0% correct) for 31 of 37 species, but overestimated extents for 13 species. The International Union for Conservation of Nature range maps encompassed 68.1% of occurrence records and were > 90% accurate for 17 of 39 species. Extralimital records represent either improved sampling and digitization or actual geographic range expansions. Here we provide new data-driven range maps, update standards for the archiving of museum-quality locational records and offer recommendations for mapping range changes for monitoring and conservation.


Assuntos
Biodiversidade , Mudança Climática , Mamíferos , Alaska , Animais , Mamíferos/fisiologia , Conservação dos Recursos Naturais , Distribuição Animal
12.
Sci Rep ; 14(1): 8257, 2024 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-38589385

RESUMO

Pacific Walruses (Odobenus rosmarus divergens [Illiger 1815]) are gregarious marine mammals considered to be sentinels of the Arctic because of their dependence on sea ice for feeding, molting, and parturition. Like many other marine mammal species, their population sizes were decimated by historical overhunting in the nineteenth and twentieth centuries. Although they have since been protected from nearly all commercial hunting pressure, they now face rapidly accelerating habitat loss as global warming reduces the extent of summer sea ice in the Arctic. To investigate how genetic variation was impacted by overhunting, we obtained mitochondrial DNA sequences from historic Pacific Walrus samples in Alaska that predate the period of overhunting, as well as from extant populations. We found that genetic variation was unchanged over this period, suggesting Pacific Walruses are resilient to genetic attrition in response to reduced population size, and that this may be related to their high vagility and lack of population structure. Although Pacific Walruses will almost certainly continue to decline in number as the planet warms and summer sea ice is further reduced, they may be less susceptible to the ratcheting effects of inbreeding that typically accompany shrinking populations.


Assuntos
Caniformia , Morsas , Animais , Morsas/genética , DNA Antigo , Ecossistema , Variação Genética
13.
PLoS One ; 19(5): e0296478, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38820381

RESUMO

More than tools for managing physical and digital objects, museum collection management systems (CMS) serve as platforms for structuring, integrating, and making accessible the rich data embodied by natural history collections. Here we describe Arctos, a scalable community solution for managing and publishing global biological, geological, and cultural collections data for research and education. Specific goals are to: (1) Describe the core features and implementation of Arctos for a broad audience with respect to the biodiversity informatics principles that enable high quality research; (2) Highlight the unique aspects of Arctos; (3) Illustrate Arctos as a model for supporting and enhancing the Digital Extended Specimen concept; and (4) Emphasize the role of the Arctos community for improving data discovery and enabling cross-disciplinary, integrative studies within a sustainable governance model. In addition to detailing Arctos as both a community of museum professionals and a collection database platform, we discuss how Arctos achieves its richly annotated data by creating a web of knowledge with deep connections between catalog records and derived or associated data. We also highlight the value of Arctos as an educational resource. Finally, we present the financial model of fiscal sponsorship by a nonprofit organization, implemented in 2022, to ensure the long-term success and sustainability of Arctos.


Assuntos
Museus , Humanos , Biodiversidade , História Natural
14.
Mol Phylogenet Evol ; 67(1): 234-45, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23403224

RESUMO

The number of sequences from both formally described taxa and uncultured environmental DNA deposited in the International Nucleotide Sequence Databases has increased substantially over the last two decades. Although the majority of these sequences represent authentic gene copies, there is evidence of DNA artifacts in these databases as well. These include lab artifacts, such as PCR chimeras, and biological artifacts such as pseudogenes or other paralogous sequences. Sequences that fall in basal positions in phylogenetic trees and appear distant from known sequences are particularly suspect. Phylogenetic analyses suggest that a novel sequence type (NS1) found in two boreal forest soil clone libraries belongs to the fungal kingdom but does not fall unambiguously within any known phylum. We have evaluated this sequence type using an array of secondary-structure analyses. To our knowledge, such analyses have never been used on environmental ribosomal sequences. Ribosomal secondary structure was modeled for four rRNA loci (ITS1, 5.8S, ITS2, 5' LSU). These models were analyzed for the presence of conserved domains, conserved nucleotide motifs, and compensatory base changes. Minimal free energy (MFE) foldings and GC contents of sequences representing the major fungal clades, as well as NS1, were also compared. NS1 displays secondary rRNA structures consistent with other fungi and many, but not all, conserved nucleotide motifs found across eukaryotes. However, our analyses show that many other authentic sequences from basal fungi lack more of these conserved motifs than does NS1. Together our findings suggest that NS1 represents an authentic gene copy. The methods described here can be used on any rRNA-coding sequence, not just environmental fungal sequences. As new-generation sequencing methods that yield shorter sequences become more widely implemented, methods that evaluate sequence authenticity should also be more widely implemented. For fungi, the adjacent 5.8S and ITS2 loci should be prioritized. This region is not only suited to distinguishing between closely related species, but it is also more informative in terms of expected secondary structure.


Assuntos
Conformação de Ácido Nucleico , RNA Ribossômico/análise , Solo/análise , Árvores , Alaska , Composição de Bases , Teorema de Bayes , DNA Fúngico/análise , DNA Espaçador Ribossômico/genética , Bases de Dados Genéticas , Funções Verossimilhança , Modelos Genéticos , Modelos Moleculares , Filogenia , RNA Ribossômico 5,8S/análise , Análise de Sequência de DNA
15.
Zootaxa ; 5228(3): 244-266, 2023 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-37044652

RESUMO

Podogymnura, a Philippine endemic genus of gymnures ("soft-furred hedgehogs"), has been known previously only from the highlands of central Mindanao (P. truei truei and P. t. minima) and from two small islands off the northeast tip of Mindanao (P. aureospinula). Based on a combination of mitochondrial genetic and qualitative and quantitative morphological data, we recognize P. minima, formerly considered a subspecies of P. truei, as a distinct species. We also recognize specimens from two little-studied montane regions of southeastern Mindanao, Mt. Hamiguitan and Mt. Kampalili, as a distinctive new species, P. intermedia n. sp. We estimate that dispersal of a common ancestor from Borneo to Mindanao ca. 1.9 to 3.5 Ma gave rise to Podogymnura, followed by speciation within Mindanao beginning 0.53 to 0.97 Ma. These results further increase the rich diversity of mammals on Mindanao, and underscore the importance of the eastern Mindanao highlands as a likely important but little-studied center of Philippine mammalian diversity.


Assuntos
Ouriços , Animais , Filipinas
16.
Sci Rep ; 12(1): 19689, 2022 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-36446809

RESUMO

Two of the most-studied ecogeographical rules describe patterns of body size variation within species. Bergmann's rule predicts that individuals have larger body sizes in colder climates (typically at higher latitudes), and the island rule predicts that island populations of small-bodied species average larger in size than their mainland counterparts (insular gigantism). These rules are rarely tested in conjunction or assessed across space and time simultaneously. We investigated these patterns in the Northern Treeshrew (Tupaia belangeri) using museum specimens collected across a wide spatial and temporal range. Contrary to Bergmann's rule, size increases with temperature in T. belangeri, a signal that is highly consistent across space and time. We also show that these rules are intertwined: Bergmann's rule is reversed on the mainland but holds on islands, and therefore the island rule is upheld at higher, but not lower, latitudes. Moreover, we demonstrate a rapid reversal of both rules over time. The mechanism behind these inversions remains unclear, though temperature and precipitation are significant predictors of body size. Ecogeographical rules rely on the assumption of a constant relationship between size and the factors driving its variation. Our results highlight the need to question this assumption and reevaluate these rules in the context of accelerating and uneven climate change.


Assuntos
Mudança Climática , Gigantismo , Humanos , Animais , Tamanho Corporal , Clima Frio , Tupaia
17.
Br J Cancer ; 105(4): 498-504, 2011 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-21792197

RESUMO

BACKGROUND: The aim was to investigate the correlation between (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) metabolic response to chemoradiotherapy and clinical outcomes in squamous cell carcinoma (SCC) of the anus. METHODS: A total of 48 patients with biopsy-proven anal SCC underwent FDG-PET scans at baseline and post chemoradiotherapy (54 Gy, concurrent 5-FU/mitomycin). Kaplan-Meier analysis was used to determine survival outcomes according to FDG-PET metabolic response. RESULTS: In all, 79% patients (n=38) had a complete metabolic response (CMR) at all sites of disease, 15% (n=7) had a CMR in regional nodes but only partial response in the primary tumour (overall partial metabolic response (PMR)) and 6% (n=3) had progressive distant disease despite CMR locoregionally (overall no response (NR)). The 2-year progression-free survival (PFS) was 95% for patients with a CMR, 71% for PMR and 0% for NR (P<0.0001). The 5-year overall survival (OS) was 88% in CMR, 69% in PMR and 0% in NR (P<0.0001). Cox proportional hazards regression analyses for PFS and OS found significant associations for incomplete (PMR+NR) vs complete FDG-PET response to treatment only, (HR 4.1 (95% CI: 1.5-11.5, P=0.013) and 6.7 (95% CI: 2.1-21.6, P=0.002), respectively). CONCLUSION: FDG-PET metabolic response to chemoradiotherapy in anal cancer is significantly associated with PFS and OS, and in this cohort incomplete FDG-PET response was a stronger predictor than T or N stage.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias do Ânus/tratamento farmacológico , Neoplasias do Ânus/radioterapia , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/radioterapia , Fluordesoxiglucose F18/metabolismo , Tomografia por Emissão de Pósitrons , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias do Ânus/diagnóstico por imagem , Neoplasias do Ânus/metabolismo , Neoplasias do Ânus/mortalidade , Austrália/epidemiologia , Carcinoma de Células Escamosas/diagnóstico por imagem , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/mortalidade , Quimioterapia Adjuvante , Fatores de Confusão Epidemiológicos , Intervalo Livre de Doença , Fracionamento da Dose de Radiação , Feminino , Seguimentos , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Tomografia por Emissão de Pósitrons/métodos , Modelos de Riscos Proporcionais , Compostos Radiofarmacêuticos/metabolismo , Radioterapia Adjuvante , Estudos Retrospectivos , Resultado do Tratamento
18.
N Engl J Med ; 359(8): 789-99, 2008 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-18650507

RESUMO

BACKGROUND: Lowering low-density lipoprotein cholesterol with statin therapy results in substantial reductions in cardiovascular events, and larger reductions in cholesterol may produce larger benefits. In rare cases, myopathy occurs in association with statin therapy, especially when the statins are administered at higher doses and with certain other medications. METHODS: We carried out a genomewide association study using approximately 300,000 markers (and additional fine-mapping) in 85 subjects with definite or incipient myopathy and 90 controls, all of whom were taking 80 mg of simvastatin daily as part of a trial involving 12,000 participants. Replication was tested in a trial of 40 mg of simvastatin daily involving 20,000 participants. RESULTS: The genomewide scan yielded a single strong association of myopathy with the rs4363657 single-nucleotide polymorphism (SNP) located within SLCO1B1 on chromosome 12 (P=4x10(-9)). SLCO1B1 encodes the organic anion-transporting polypeptide OATP1B1, which has been shown to regulate the hepatic uptake of statins. The noncoding rs4363657 SNP was in nearly complete linkage disequilibrium with the nonsynonymous rs4149056 SNP (r(2)=0.97), which has been linked to statin metabolism. The prevalence of the rs4149056 C allele in the population was 15%. The odds ratio for myopathy was 4.5 (95% confidence interval [CI], 2.6 to 7.7) per copy of the C allele, and 16.9 (95% CI, 4.7 to 61.1) in CC as compared with TT homozygotes. More than 60% of these myopathy cases could be attributed to the C variant. The association of rs4149056 with myopathy was replicated in the trial of 40 mg of simvastatin daily, which also showed an association between rs4149056 and the cholesterol-lowering effects of simvastatin. No SNPs in any other region were clearly associated with myopathy. CONCLUSIONS: We have identified common variants in SLCO1B1 that are strongly associated with an increased risk of statin-induced myopathy. Genotyping these variants may help to achieve the benefits of statin therapy more safely and effectively. (Current Controlled Trials number, ISRCTN74348595.)


Assuntos
Inibidores de Hidroximetilglutaril-CoA Redutases/efeitos adversos , Doenças Musculares/induzido quimicamente , Transportadores de Ânions Orgânicos/genética , Polimorfismo de Nucleotídeo Único , Sinvastatina/efeitos adversos , Idoso , Arteriopatias Oclusivas/tratamento farmacológico , Cromossomos Humanos Par 12 , Diabetes Mellitus/tratamento farmacológico , Feminino , Marcadores Genéticos , Genótipo , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacocinética , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Transportador 1 de Ânion Orgânico Específico do Fígado , Masculino , Pessoa de Meia-Idade , Doenças Musculares/genética , Infarto do Miocárdio/tratamento farmacológico , Infarto do Miocárdio/prevenção & controle , Risco , Sinvastatina/uso terapêutico
19.
Mol Phylogenet Evol ; 60(3): 358-72, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21565274

RESUMO

Resolving the phylogeny of treeshrews (Order Scandentia) has historically proven difficult, in large part because of access to specimens and samples from critical taxa. We used "antique" DNA methods with non-destructive sampling of museum specimens to complete taxon sampling for the 20 currently recognized treeshrew species and to estimate their phylogeny and divergence times. Most divergence among extant species is estimated to have taken place within the past 20 million years, with deeper divergences between the two families (Ptilocercidae and Tupaiidae) and between Dendrogale and all other genera within Tupaiidae. All but one of the divergences between currently recognized species had occurred by 4Mya, suggesting that Miocene tectonics, volcanism, and geographic instability drove treeshrew diversification. These geologic processes may be associated with an increase in net diversification rate in the early Miocene. Most evolutionary relationships appear consistent with island-hopping or landbridge colonization between contiguous geographic areas, although there are exceptions in which extinction may play an important part. The single recent divergence is between Tupaia palawanensis and Tupaia moellendorffi, both endemic to the Philippines, and may be due to Pleistocene sea level fluctuations and post-landbridge isolation in allopatry. We provide a time-calibrated phylogenetic framework for answering evolutionary questions about treeshrews and about evolutionary patterns and processes in Euarchonta. We also propose subsuming the monotypic genus Urogale, a Philippine endemic, into Tupaia, thereby reducing the number of extant treeshrew genera from five to four.


Assuntos
Evolução Biológica , Filogenia , Escandêntias/classificação , Animais , Sudeste Asiático , DNA Mitocondrial/genética , Conformação de Ácido Nucleico , Filogeografia , Escandêntias/genética , Análise de Sequência de DNA
20.
Allergy ; 66(1): 68-75, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20716321

RESUMO

BACKGROUND: Day care centre attendance is much more common in East than in West Germany. Although there is evidence that early day care might be protective against atopic diseases, several studies have shown a higher prevalence of childhood eczema in East Germany compared to West Germany. OBJECTIVES: To compare prevalence and cumulative incidence of eczema in a birth cohort study in East and West Germany and to identify risk factors that are associated with eczema, which might explain regional differences. METHODS: We used data from the ongoing population-based birth cohort study Influence of Life-style factors on the development of the Immune System and Allergies in East and West Germany Plus the influence of traffic emissions and genetics. In 1997, 3097 children from study areas in East and West Germany were recruited. Cumulative incidence and 1-year prevalences of eczema up to the age of 6 years were determined from yearly questionnaires. Cox regression and generalized estimating equations/logistic regression were used to quantify regional differences and to identify risk factors that might explain them. RESULTS: Prevalence and incidence of eczema were higher in children living in East Germany than those living in West Germany. We identified 11 risk factors that showed significant regional differences. From these factors, only 'day care attendance during the first 2 years of life' was significantly associated with eczema (odds ratio 1.56, 95% confidence interval CI 1.31-1.86). The regional differences in eczema could be explained by differences in early day care utilization. CONCLUSION: Day care centre attendance is associated with an increased prevalence and incidence of eczema. Regional differences in eczema prevalence could be explained by regional differences in utilization of early day care.


Assuntos
Absenteísmo , Creches/estatística & dados numéricos , Eczema/epidemiologia , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Alemanha Oriental/epidemiologia , Alemanha Ocidental/epidemiologia , Pesquisas sobre Atenção à Saúde , Humanos , Incidência , Lactente , Estilo de Vida , Masculino , Prevalência , Fatores de Risco , Meio Social , Inquéritos e Questionários
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA