RESUMO
Mountains support a great diversity of species and habitat types. Grasslands are the dominant landscape in the Andes and play an important ecological role. However, they are threatened by many factors, including climate change and human activities. The spatial distribution of species that compose, and the ecological and evolutionary factors that provide for the spatial biodiversity patterns, are little known. The largest Poa L. (Poaceae) genera are widely diversified and distributed in the Andes. In particular, P. scaberula Hook. f. shows great environmentally mediated phenotypic plasticity, and is distributed from North America to the tip of South America. However, the impact of environmental variables has on the spatial distribution of this species, remain largely unknown. Using high-resolution climatic data, herein we modeled the current suitable habitat for P. scaberula and identified the main climatic variables that best predict its potential distribution. In addition, we assess the species status in the predicted habitats through herbarium data and relate it with species distribution models. The models showed that P. scaberula has a suitable habitat of ca. 162.747 km2 along the Andes and high elevation regions. The most influential variables with a 68.5% contribution to the distribution of the species, particularly high elevation areas, included mean cold hardiness, water vapor pressure and temperature seasonality. The areas of greatest suitability with the highest occurrence of the species were identified geographically by the models. The present study provides useful information that can assist in the identification of areas where the species is most sensitive to different variables, including climate change and human activities and contributes in assessing the conservation status of Andean grassland at a regional scale.
RESUMO
The Andean Puna is an arid, high-elevation plateau in which plants such as grasses experience high abiotic stress and distinctive environmental conditions. We assessed colonization by arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) in the roots of 20 native grass species and examined the relationship between root-associated fungi (AMF and DSE) as a function of the elevation of study sites, the photosynthetic pathways of the grass hosts, and the hosts' life cycles. In general, grasses were co-colonized by AMF and DSE and the colonization by AMF and DSE was not extensive. The extension of colonization of AMF and that of DSE were positively correlated, as were number of arbuscules and DSE colonization extension. The extension of AMF colonization differed among sites with different elevations, but DSE colonization was similar across sites. Overall, AMF and DSE patterns shifted as a function of elevation in most grass species, with no general trends observed with respect to host photosynthetic pathway or life cycle. In general, our observations differ from previous studies in the Northern Hemisphere. Variation among sites in AMF and DSE colonization was greater than variation that could be explained by the other factors considered here, suggesting a strong influence of environmental factors. We predict that both AMF and DSE may have established synergistic and beneficial associations with grasses in these distinctive and harsh ecosystems.
Assuntos
Endófitos/isolamento & purificação , Interações entre Hospedeiro e Microrganismos , Micorrizas/isolamento & purificação , Poaceae/microbiologia , Argentina , Ecossistema , Endófitos/fisiologia , Micorrizas/fisiologia , Micorrizas/ultraestrutura , Fotossíntese/fisiologia , Filogenia , Raízes de Plantas/microbiologia , Plantas/anatomia & histologia , Plantas/microbiologia , Microbiologia do SoloRESUMO
Here we conduct research to understand the evolutionary history of a shrubby species known as Agarito (Berberis trifoliolata), an endemic species to the Chihuahuan Desert. We identify genetic signatures based on plastid DNA and AFLP markers and perform niche modelling and spatial connectivity analyses as well as niche modelling based on records in packrats to elucidate whether orogenic events such as mountain range uplift in the Miocene or the contraction/expansion dynamics of vegetation in response to climate oscillations in the Pliocene/Pleistocene had an effect on evolutionary processes in Agarito. Our results of current niche modelling and palaeomodelling showed that the area currently occupied by Berberis trifoliolata is substantially larger than it was during the Last Interglacial period and the Last Glacial Maximum. Agarito was probably confined to small areas in the Northeastern and gradually expanded its distribution just after the Last Glacial Maximum when the weather in the Chihuahuan Desert and adjacent regions became progressively warmer and drier. The most contracted range was predicted for the Interglacial period. Populations remained in stable areas during the Last Glacial Maximum and expanded at the beginning of the Holocene. Most genetic variation occured in populations from the Sierra Madre Oriental. Two groups of haplotypes were identified: the Mexican Plateau populations and certain Northeastern populations. Haplogroups were spatially connected during the Last Glacial Maximum and separated during interglacial periods. The most important prediction of packrat middens palaeomodelling lies in the Mexican Plateau, a finding congruent with current and past niche modelling predictions for agarito and genetic results. Our results corroborate that these climate changes in the Pliocene/Pleistocene affected the evolutionary history of agarito. The journey of agarito in the Chihuahuan Desert has been dynamic, expanding and contracting its distribution range and currently occupying the largest area in its history.
Assuntos
Berberis/genética , Fósseis , Loci Gênicos , Variação Genética , Análise do Polimorfismo de Comprimento de Fragmentos Amplificados , Animais , Teorema de Bayes , Berberis/classificação , DNA de Cloroplastos , Clima Desértico , Evolução Molecular , Genética Populacional , Haplótipos , México , Modelos Teóricos , Filogenia , Filogeografia , Plastídeos/genéticaRESUMO
BACKGROUND AND AIMS: Poa subgenus Poa supersect. Homalopoa has diversified extensively in the Americas. Over half of the species in the supersection are diclinous; most of these are from the New World, while a few are from South-East Asia. Diclinism in Homalopoa can be divided into three main types: gynomonoecism, gynodioecism and dioecism. Here the sampling of species of New World Homalopoa is expanded to date its origin and diversification in North and South America and examine the evolution and origin of the breeding system diversity. METHODS: A total of 124 specimens were included in the matrix, of which 89 are species of Poa supersect. Homalopoa sections Acutifoliae, Anthochloa, Brizoides, Dasypoa, Dioicopoa, Dissanthelium, Homalopoa sensu lato (s.l.), Madropoa and Tovarochloa, and the informal Punapoa group. Bayesian and parsimony analyses were conducted on the data sets based on four markers: the nuclear ribosomal internal tanscribed spacer (ITS) and external transcribed spacer (ETS), and plastid trnT-L and trnL-F. Dating analyses were performed on a reduced Poa matrix and enlarged Poaceae outgroup to utilize fossils as calibration points. A relaxed Bayesian molecular clock method was used. KEY RESULTS: Hermaphroditism appears to be pleisiomorphic in the monophyletic Poa supersect. Homalopoa, which is suggested to have originated in Eurasia 8·4-4·2 million years ago (Mya). The ancestor of Poa supersect. Homalopoa radiated throughout the New World in the Late Miocene-Early Pliocene, with major lineages originating during the Pliocene to Pleistocene (5-2 Mya). Breeding systems are linked to geographic areas, showing an evolutionary pattern associated with different habitats. At least three major pathways from hermaphroditism to diclinism are inferred in New World Homalopoa: two leading to dioecism, one via gynodioecism in South America and another directly from hermaphroditism in North America, a result that needs to be checked with a broader sampling of diclinous species in North America. A third pathway leads from hermaphroditism to gynomonoecism in Andean species of South America, with strictly pistillate species evolving in the highest altitudes. CONCLUSIONS: Divergence dating provides a temporal context to the evolution of breeding systems in New World Poa supersect. Homalopoa The results are consistent with the infrageneric classification in part; monophyletic sections are confirmed, it is proposed to reclassify species of sect. Acutifoliae, Dasypoa and Homalopoa s.l. and it is acknowledged that revision of the infrageneric taxonomy of the gynomonoecious species is needed.
Assuntos
Melhoramento Vegetal , Poa/genética , Poaceae/genética , Teorema de Bayes , Evolução Biológica , DNA de Plantas/química , DNA de Plantas/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Flores/classificação , Flores/genética , Fósseis , América do Norte , Filogenia , Plastídeos/genética , Poa/classificação , Poaceae/classificação , Análise de Sequência de DNA , América do SulRESUMO
UNLABELLED: ⢠PREMISE OF THE STUDY: In angiosperms, several carpel tissues are specialized to facilitate pollen-tube elongation to achieve fertilization. We evaluated the possible evolutionary pathways of the diverse female reproductive tracts in Nyctaginaceae.⢠METHODS: We studied the anatomy of a range of species representing different tribes, using light, fluorescence, scanning electron, and transmission electron microscopy.⢠KEY RESULTS: Stigmas have multicellular, multiseriate papillae, except for Boerhavia diffusa with unicellular papillae. The styles are solid, with a strand of transmitting tissue linking the stigma with the ventral ovary wall. In Allionia, Boerhavia, and Mirabilis, the transmitting tissue branches into two independent tracts at the base of the ovary and continues across the lateral margins of the funicle to the micropyle; it is composed of cells with thick walls surrounded by abundant extracellular matrix. Bougainvillea, Pisonia, and Pisoniella have a diffuse transmitting tissue and an obturator, a proliferation of cells covered by a layer of secretory papillae that encloses the funicle, placenta, and ventral wall of the gynoecium and contacts with the micropyle.⢠CONCLUSIONS: We propose two models of female reproductive tract, (A) one in which an obturator is absent and the transmitting tissue is compact and branched and (B) one in which an obturator is present and the transmitting tissue is diffuse. On the basis of character optimization, we hypothesize that model B represents the ancestral (plesiomorphic) condition in the family and model A originated once during evolution, within the tribe Nyctagineae.
Assuntos
Flores/ultraestrutura , Modelos Estruturais , Nyctaginaceae/ultraestrutura , Evolução Biológica , Análise por Conglomerados , Fertilização , Flores/genética , Nyctaginaceae/genética , Tubo Polínico/genética , Tubo Polínico/ultraestrutura , Polinização , Reprodução , Especificidade da EspécieRESUMO
The South American Transition Zone (SATZ) is a biogeographic area in which not only orogeny (Andes uplift) and climate events (aridification) since the mid-Miocene, but also Quaternary glaciation cycles had an important impact on the evolutionary history of the local flora. To study this effect, we selected Munroa argentina, an annual grass distributed in the biogeographic provinces of Puna, Prepuna and Monte. We collected 152 individuals from 20 localities throughout the species' range, ran genetic and demographic analyses, and applied ecological niche modeling. Phylogenetic and population genetic analyses based on cpDNA and AFLP data identified three phylogroups that correspond to the previously identified subregions within the SATZ. Molecular dating suggests that M. argentina has inhabited the SATZ since approximately 3.4 (4.2-1.2) Ma and paleomodels predict suitable climate in these areas during the Interglacial period and the Last Glacial Maximum. We conclude that the current distribution of M. argentina resulted from the fragmentation of its once continuous range and that climate oscillations promoted ecological differences that favored isolation by creating habitat discontinuity.
Assuntos
DNA de Plantas/análise , Poaceae/crescimento & desenvolvimento , Poaceae/genética , Evolução Biológica , Ecossistema , Genética Populacional , Filogeografia , Poaceae/classificação , América do SulRESUMO
Relatamos um caso de paciente do sexo feminino, 48 anos, com quadro clínico de dor abdominal de moderada intensidade e abaulamento do abdome. Ao exame físico constatou-se massa abdominal palpável. A tomografia computadorizada mostrou volumosa massa retroperitoneal, com realce heterogêneo e íntima relação com a veia cava inferior. Realizou-se ressecção em bloco da massa e do segmento invadido da veia cava. A histologia revelou leiomiossarcoma.
The authors report a case of a 48 year-old female patient with moderate abdominal pain and bulging in the abdomen. Physical examination demonstrated the presence of a palpable abdominal mass. Computed tomography showed a heterogeneously enhancing retroperitoneal mass in close contact with the inferior vena cava. En bloc resection of the mass and of the attached vena cava segment was performed. Histological analysis revealed leiomyosarcoma.
RESUMO
A síndrome de Churg-Strauss é uma doença sistêmica rara caracterizada principalmente por hipereosinofilia, asma e vasculite. O pulmão é o órgão mais frequentemente envolvido. Neste relato, descrevemos uma alteração relativamente rara nesta doença - a presença de um nódulo pulmonar -, ao mesmo tempo que recordamos os principais achados obtidos em exames radiológicos e os seus diagnósticos diferenciais mais importantes.
Churg-Strauss syndrome is a rare systemic disease primarily characterized by hypereosinophilia, asthma and vasculitis. The lung is the organ most frequently involved. In the present report, the authors describe a relatively rare finding in this disease - the presence of a pulmonary nodule -, while recalling the main radiological findings and the most relevant differential diagnoses.
RESUMO
Churg-Strauss syndrome is a rare systemic disease primarily characterized by hypereosinophilia, asthma and vasculitis. The lung is the organ most frequently involved. In the present report, the authors describe a relatively rare finding in this disease - the presence of a pulmonary nodule -, while recalling the main radiological findings and the most relevant differential diagnoses.
A síndrome de Churg-Strauss é uma doença sistêmica rara caracterizada principalmente por hipereosinofilia, asma e vasculite. O pulmão é o órgão mais frequentemente envolvido. Neste relato, descrevemos uma alteração relativamente rara nesta doença - a presença de um nódulo pulmonar -, ao mesmo tempo que recordamos os principais achados obtidos em exames radiológicos e os seus diagnósticos diferenciais mais importantes.
RESUMO
The authors report a case of a 48 year-old female patient with moderate abdominal pain and bulging in the abdomen. Physical examination demonstrated the presence of a palpable abdominal mass. Computed tomography showed a heterogeneously enhancing retroperitoneal mass in close contact with the inferior vena cava. En bloc resection of the mass and of the attached vena cava segment was performed. Histological analysis revealed leiomyosarcoma.
Relatamos um caso de paciente do sexo feminino, 48 anos, com quadro clínico de dor abdominal de moderada intensidade e abaulamento do abdome. Ao exame físico constatou-se massa abdominal palpável. A tomografia computadorizada mostrou volumosa massa retroperitoneal, com realce heterogêneo e íntima relação com a veia cava inferior. Realizou-se ressecção em bloco da massa e do segmento invadido da veia cava. A histologia revelou leiomiossarcoma.
RESUMO
The relationships of altitude, host life cycle (annual or perennial) and photosynthetic pathway (C(3) or C(4) ) with arbuscular mycorrhiza (AM) root colonization were analysed in 35 species of Andean grasses. The study area is located in north-western Argentina along altitudinal sites within the Puna biogeographical region. Twenty-one sites from 3320 to 4314 m were sampled. Thirty-five grasses were collected, and the AM root colonization was quantified. We used multivariate analyses to test emerging patterns in these species by considering the plant traits and variables of AM colonization. Pearson's correlations were carried out to evaluate the specific relationships between some variables. Most grasses were associated with AM, but the colonization percentages were low in both C(3) and C(4) grasses. Nevertheless, the AM root colonization clearly decreased as the altitude increased. This distinctive pattern among different species was also observed between some of the populations of the same species sampled throughout the sites. An inverse relationship between altitude and AM colonization was found in this Southern Hemisphere Andean system. The effect of altitude on AM colonization seems to be more related to the grasses' photosynthetic pathway than to life cycles. This study represents the first report for this biogeographical region.
Assuntos
Altitude , Micorrizas/fisiologia , Fotossíntese , Poaceae/microbiologia , Argentina , Raízes de Plantas/microbiologiaRESUMO
This is the first report on chromosome numbers and the reproductive behaviour in Stenodrepanum Harms, a rare endemic and monotypic legume genus from the arid and salty areas of central-western Argentina. Sixty individuals belonging to two populations from two salty areas ("salinas") were surveyed and included mostly triploid (2n = 3x = 36) and only two diploid (2n = 2x = 24) plants. Meiosis in diploids is regular, with bivalent pairing and uniform and viable pollen. In contrast, meiosis in triploids is characterized by high trivalent pairing, with irregularly shaped pollen and variation in cytoplasm content and stainability, which is in agreement with an unbalanced segregation occurring in anaphases I and II. However, different triploid plants/individuals showed various degrees of pollen fertility, which may be attributed to particular genotypes. Research on reproductive biology events indicates sexual cross-pollinated reproduction enhanced by protogyny in both cytotypes. All plants produced seeds, but seedlings were only recovered from diploid plants pollinated with triploids, and even those eventually perished. Chromosome counts in these seedlings revealed aneuploid chromosome numbers owing to the combination of unbalanced gametes.
Assuntos
Cromossomos de Plantas/genética , Fabaceae/crescimento & desenvolvimento , Fabaceae/genética , Ploidias , Argentina , Diploide , Fertilidade/genética , Variação Genética , MeioseRESUMO
Objetivo: Avaliar in vitro o grau de clareamento e de desmineralização do esmalte humano submetido à ação de dentifrício clareador. Metodologia: Pré-molares escurecidos foram escovados com dentifrícios contendo H2O2 ou bicarbonato de sódio por 28 dias. A eficácia destas substâncias foi comparada à ação do gel de peróxido de carbamida. O clareamento foi determinado por espectrofotometria - Sistema CIELab - e a desmineralização por laser de diodo. Resultados: Após 28 dias de escovação com o dentifrício contendo H2O2 constatou-se aumento de luminosidade e redução do parâmetro a*; com 14 dias de aplicação do gel ocorreu a eliminação da pigmentação. As médias dos valores de ΔE para os grupos controle negativo e submetidos ao gel e aos dentifrícios contendo H2O2 e NaHCO3 foram, respectivamente: 26,27±8,66; 6,82±3,89; 16,78±6,22 e 29,21±5,07. A desmineralização inicial dos grupos revelou grau reduzido. Realizada a pigmentação, a descalcificação aumentou com exceção do grupo tratado com o gel. Conclusão: Há redução da desmineralização do esmalte, aumento do parâmetro L* e redução de a* após 28 dias de escovação com dentifrício contendo H2O2. O dentifrício com o abrasivo NaHCO3 não tem eficácia clareadora e resulta em desmineralização.
Purpose: To assess in vitro the degree of whitening and demineralization in human enamel after treatment with whitening toothpastes. Methods: Darkened premolars were brushed with toothpastes containing H2O2 or NaHCO3 for 28 days. The efficacy of the whitening substances was assessed in comparison with the action of carbamide peroxide (CP) gel. Whitening was determined by using a spectrophotometer (CIELab System) and the demineralization was assessed by means of diode laser. Results: After 28 days of brushing with a toothpaste containing H2O2 there was an increase in brightness and a reduction in the parameter a*; after 14 days of gel application, pigmentation elimination was obtained. The mean ΔE values for the negative control group, group treated with CP gel, and groups treated with toothpastes containing H2O2 or NaHCO3 were: 26.27±8.66; 6.82±3.89; 16.78±6.22; and 29.21±5.07. The initial demineralization was low. Demineralization increased after pigmentation except for the group that had been treated with CP gel. Conclusion: Toothbushing with H2O2 toothpaste reduced enamel demineralization, increased the L* parameter, and reduced the a*parameter after 28 days. The toothpaste containing NaHCO3 abrasive did not have any whitening effect nor inhibit demineralization.
Assuntos
Humanos , Clareamento Dental/métodos , Dentifrícios/uso terapêutico , Desmineralização do Dente , Técnicas In Vitro , Estudos de Casos e ControlesRESUMO
Objetivo: Avaliar, in vitro, o grau de clareamento e seqüelas de desmineralização do esmalte humano submetido à ação dedentifrício clareador. Método: Estudo experimental in vitro descritivo-analítico. A amostra compreendeu pré-molares, os quais tiveram as porções coronárias seccionadas e incluídas em resina o-ftálica. Os corpos-de-prova foram agrupados, aleatoriamente, em seis grupos de 12 unidades constituindo, desta forma, dois grupos experimentais (D1 e D2), um grupo controle positivo (CP), um grupo controle negativo (CN), um grupo repetitividade (GR) e um grupo estabilidade de cor (GE). O clareamento foi determinado por espectrofotometria e a desmineralização pelo laser de diodo. Resultados: Os espécimes revelaram redução da luminosidade (L*) e aumento dos parâmetros a* (vermelho) e b*(amarelo). Após 28 dias de escovação com o dentifrício contendo peróxido de carbamida constatou-se aumento de luminosidade e redução do parâmetro a*. Após 14 dias de aplicação do gel verificou-se a eliminação da pigmentação. Foram constatadas as seguintes médias dos valores de ΔE para os grupos controle negativo e submetidos ao gel e aos dentifrícios contendo peróxido de carbamida e bicarbonato de sódio: 26,27 ± 8,66; 6,82±3,89; 14,53± 4,91 e 29,21± 5,07. A desmineralização inicial dos grupos revelou reduzido grau. Realizada a pigmentação, a descalcificação aumentou apesar de mantidos em solução remineralizante, à exceção do grupo tratado com o gel. Conclusão: Há redução da desmineralização do esmalte, aumento do parâmetro L* e redução do a* após 28 dias de escovação por dentifrício contendo peróxido de carbamida; dentifrício contendo o abrasivo bicarbonato de sódio não tem eficácia clareadora e resulta em desmineralização.
Assuntos
Clareamento Dental/métodos , Dentifrícios , Desmineralização do Dente/diagnóstico , Esmalte Dentário/química , Espectrofotometria/métodos , Técnicas In Vitro , Cimentos de Resina , Técnica de Descalcificação/métodos , Estatísticas não ParamétricasRESUMO
O abscesso esplênico é uma doença rara, com cerca de 1000 casos relatados mundialmente. Devido à inespecificidade do quadro clínico, apresenta diagnósticodifícil. Porém, a melhora da acurácia de exames de imagem e da antibioticoterapia, tem favorecido o prognóstico destes pacientes. O objetivo deste trabalho é relatar um caso de abscesso esplênico em paciente de 13 anos, portador de cardite reumática, que foi tratado com drenagem percutânea associado à antibioticoterapia.Palavras-chave: Abscesso; Baço; Sucção (drenagem); Endocardite bacteriana; Cardiopatia reumática(AU).Splenic abscess is a rare disease with roughly 1,000 cases reported in the world. Due to the unspecific clinical symptoms the diagnosis is difficult. However theimprovement in the accuracy of image exams and antibiotics therapy has considerably favored the patients prognoses. The aim of this paper is to report acase of splenic abscess in a boy aged 13, with rheumatic heart disease, who was treated with percutaneous drainage linked to antibiotic therapy. Key words: Abscess; Spleen; Succion (drainage); Bacterial endocarditis; Rheumatic heart disease
Assuntos
Abscesso , Endocardite Bacteriana , Cardiopatia Reumática , Baço , SucçãoRESUMO
la pequeña población campesina de El Puesto, zona aledaña a la localidad de Cerro Colorado (Reserva Cultural-Natural), Córdoba, Argentina. Siete familias (el 100% de la población) fueron entrevistadas mediante un cuestionario semi-estructurado, con el propósito de registrar las plantas medicinales que conocen y utilizan. Se realizó un análisis comparativo entre diferentes categorías de uso de las plantas, considerando los diferentes ambientes en donde se recolectó material vegetal. Las personas mencionaron un total de 55 especies botánicas que son utilizadas con fines medicinales. Se registraron los nombres locales y científicos, parte de la planta utilizada, métodos de colección y aplicación y modos de curación. Además, se consideró la relación entre la frecuencia de uso de las especies, las características de la vegetación del área y algunos de los posibles factores culturales que pueden influenciar su utilización. (AU)
Assuntos
Humanos , Plantas Medicinais , População Rural , Argentina , Etnobotânica , Medicina TradicionalRESUMO
Introdução: As alterações mais freqüentes da cavidade oral são a cárie e a doença periodontal. A periodontite apresenta dois estágios: gengivite e periodontite. A destruição das fibras colágenas que inserem o dente ao osso alveolar é característica da periodontite. A perda de inserção causada por esta patologia decorre da presença de bactérias e seus produtos, além da destruição tecidual. Este processo é causado pela liberação excessiva das células de defesa do organismo que alcançam a área lesada, dentre essas células encontram-se os neutrófilos. Estes liberam seus grânuloslisossomias onde estão presentes enzimas conhecidas como proteases (elastase, colagenase e catepsina G) e, quando liberadas em excesso, causam extensas destruições teciduais.A defesa inata do organismo responde a este processo ativando antiproteases, tais como, alfa-1-antitripsina e alfa-2-macrogoblulina, consequentemente, debelando o processo inflamatório. Objetivo: Realizar uma vasta revisão da literaturaa cerca da periodontite e seus marcadores. Na periodontite o equilíbrio entre proteases e antiproteases parece estar alterado levando o aparecimento desta. Há um aumento da prevalênciada doença periodontal na população mundial. Esta, mais recentemente, tem sido associada a condições sistêmicas que conduzem a destruição tecidual. A causa da periodontite talvez esteja baseada em uma reação tecidual exacerbada do que na agressão bacteriana propriamente dita. Conclusão: A predisposição do organismo é um fator relevante para o desenvolvimento desta doença. Através da leitura de diferentes estudos foi observado que as proteases liberadas durante o processo de degranulação dos neutrófilos são de origem interna e não bacteriana.