155 research outputs found

    In vitro spore germination and gametophyte development of two Cyathea species of South America in response to nutrient media

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    Abstract Cyathea corcovadensis and Cyathea phalerata are tree ferns native to Brazil, endangered in the state of Rio Grande do Sul. Spore germination and gametophyte development in media with different nutrient formulations and activated charcoal were evaluated, aiming to develop a process for obtaining plants of the two species. Spores were sown in four semi-solid culture media: Meyer, Dyer, MS with 50% and MS with 25% of the original macronutrient concentration. For each medium, 10 replicates were carried out (flasks with 5 mg of spores/30 mL of medium), with and without 1% activated charcoal, respectively. Spore germination and gametophytic development (laminar and cordate stages) were quantified at 30, 60 and 90 days of culture. Cyathea corcovadensis and C. phalerata germinated and developed gametophytes in all media. For both species, the highest percentages of germination and cordate gametophytes (more advanced development stage) were recorded in Meyer medium without activated charcoal, which has higher concentrations of macronutrients and no micronutrients compared to the other evaluated media. We recommend cultivating the plants in Meyer medium for greater gametophytic development and subsequent sporophyte obtention, as a biotechnological tool for C. corcovadensis and C. phalerata conservation and for environmental restoration and enrichment using these tree ferns

    Successful Tulasnella amonilioides isolation from wild Cattleya intermedia and effectiveness of the mycobiont on in vitro propagation of this threatened Orchidaceae

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    This is the first study that report symbiosis in Cattleya, aiming to isolate and identify mycorrhizal fungi capable of promoting germination of this orchid, and to evaluate the development of symbiotically propagated individuals. We compared seed germination percentage, growth index and morphometric variables of seedlings propagated symbiotically in OMA medium with individuals that were non-symbiotically propagated in MS medium. Fungi isolates were identified by phylogenetic analysis and eight of the nine isolates that were efficient in C. intermedia propagation were identified as Tulasnella amonilioides. The mycobiont improved C. intermedia seed germination and plant development when compared with OMA medium without fungi (negative control). Seedlings propagated by symbiotic culture with T. amonilioides produced more leaves and longer roots, while shoot height and number of roots were lower than for seedlings propagated in MS medium with the addition of activated charcoal. Fresh mass of seedlings propagated by symbiotic and asymbiotic techniques were equal, except when seedlings were grown in MS without activated charcoal. Tulasnella amonilioides enhances the in vitro propagation of C. intermedia and provides plants that facilitate symbiotic processes in reintroduction environments.This is the first study that reports symbiosis in Cattleya, aiming to isolate and identify mycorrhizal fungi capable of promoting the germination of this orchid and to evaluate the development of symbiotically propagated individuals. We compared seed germination percentage, growth index, and morphometric variables of seedlings propagated symbiotically in oatmeal agar (OMA) medium with individuals that were non-symbiotically propagated in Murashige and Skoog (MS) medium. Fungi isolates were identified by phylogenetic analysis and eight of the nine isolates that were efficient in C. intermedia propagation were identified as Tulasnella amonilioides. The mycobiont improved C. intermedia seed germination and plant development when compared with OMA medium without fungi (negative control). Seedlings propagated by symbiotic culture with T. amonilioides produced more leaves and longer roots, while shoot height and a number of roots were lower than for seedlings propagated in MS medium with the addition of activated charcoal. The fresh mass of seedlings propagated by symbiotic and a symbiotic techniques was equal, except when seedlings were grown in MS without activated charcoal. T. amonilioides enhance the in vitro propagation of C. intermedia and provide plants that facilitate symbiotic processes in reintroduction environments

    Transloca√ß√£o da brom√©lia epif√≠tica Vriesea incurvata: uma eficiente ferramenta para a restaura√ß√£o da biodiversidade na Floresta Atl√Ęntica

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    Micropropagation of epiphytic bromeliads associated to translocation may act as an important tool for conservation, restauration or mitigation initiatives. Vriesea incurvata is an epiphytic tank-forming bromeliad endemic to the Atlantic Forest, being an important species in gallery forest environments. Seeds of V. incurvata were germinated in vitro, and plants were acclimatized and translocated to each of two microhabitats (gallery forest and forest interior) of an Atlantic Forest fragment in South Brazil that harbors few individuals of the species. The 152 plants (76 per microhabitat) were monitored for survival and development, and abiotic data were recorded. There was increased development of morphometric parameters of the plants in the gallery forest, and survival rate ensured an 800% increase in the original population of V. incurvata in the study area. Plant survival and development parameters were positively related to light and relative air humidity. In gallery forest, plants flowered and set fruit, indicating their relationship with pollinators, since V. incurvata provides food for fauna. Further, the establishment of the individuals increased the availability of water in the canopy by accumulation in the rosettes, as well as the complexity of the canopy structure, providing a site for the occurrence of detritivorous, predatory and herbivorous arthropods. Thus, based on the method applied to V. incurvata, inserting epiphytic species into forest environments can be an efficient tool for artificial habitat regeneration, incrementing functional diversity and improving environmental quality.A micropropaga√ß√£o associada √† transloca√ß√£o de brom√©lias epif√≠ticas pode atuar como importante ferramenta para iniciativas de conserva√ß√£o, restaura√ß√£o e mitiga√ß√£o. Vriesea incurvata √© uma brom√©lia epif√≠tica formadora de tanque, end√™mica √† Floresta Atl√Ęntica, sendo uma esp√©cie importante em ambientes de floresta de galeria. Sementes de V. incurvata foram germinadas in vitro e plantas foram aclimatizadas e translocadas para dois micro-h√°bitats (floresta de galeria e interior florestal) de um fragmento de Floresta Atl√Ęntica no Sul do Brasil que abriga poucos indiv√≠duos da esp√©cie. As 152 plantas (76 por micro-h√°bitat) foram monitoradas para sobreviv√™ncia e desenvolvimento, e dados abi√≥ticos foram registrados. Houve maior desenvolvimento dos par√Ęmetros morfom√©tricos das plantas na floresta de galeria, e a taxa de sobreviv√™ncia assegurou 800% de aumento da popula√ß√£o original de V. incurvata na √°rea de estudo. A sobreviv√™ncia e os par√Ęmetros de desenvolvimento das plantas relacionaram-se positivamente com luz e umidade relativa do ar. Na floresta de galeria, as plantas floresceram e produziram frutos, indicando sua rela√ß√£o com polinizadores, uma vez que V. incurvata prov√™ alimento para a fauna. Al√©m disso, o estabelecimento de indiv√≠duos aumentou a disponibilidade de √°gua na copa por meio do ac√ļmulo nas rosetas e a complexidade da estrutura da copa, fornecendo um s√≠tio para a ocorr√™ncia de artr√≥podes detrit√≠voros, predadores e herb√≠voros. Assim, com base no m√©todo aplicado em V. incurvata, inserir esp√©cies epif√≠ticas em ambientes florestais pode ser uma eficiente ferramenta para a regenera√ß√£o artificial de h√°bitats, incrementando a diversidade funcional e melhorando a qualidade ambiental

    Análise temporal da genotoxicidade e fatores ambientais relacionados à qualidade da água de uma bacia hidrográfica no Sul do Brasil

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    Environmental pollution is one of the main problems underlying the current scenario of degradation of aquatic ecosystems. This study aimed to determine the water quality of the Rio dos Sinos watershed in South Brazil by analyzing genotoxicity and environmental factors of four sub-basins in two periods (P1 = 2012 ‚Äď 2013 and P2 = 2018 ‚Äď 2019). Water genotoxicity was analyzed using the micronucleus test with Tradescantia pallida var. purpurea. In parallel, a Rapid Habitat Assessment Protocol (RHAP) was employed and data on physico-chemical parameters, land use and occupation and the number of inhabitants were collected and examined for possible relationships with genotoxicity. Genotoxicity did not differ significantly over time for three of the four studied sub-basins. There was a significant relationship between water genotoxicity and number of inhabitants. Furthermore, environments with high genotoxicity, low water quality and high environmental degradation in the first monitoring period remained in the same condition in the second monitoring period; the most preserved areas of the basin may come to resemble these environments in the future.A polui√ß√£o ambiental √© um dos principais problemas relacionados ao atual cen√°rio de degrada√ß√£o dos ecossistemas aqu√°ticos. O objetivo deste estudo foi determinar a qualidade da √°gua da Bacia Hidrogr√°fica do Rio dos Sinos, no sul do Brasil, por meio da an√°lise da genotoxicidade e de fatores ambientais integrados de quatro sub-bacias, em dois per√≠odos bianuais de monitoramento (P1 = 2012-2013 e P2 = 2018-2019). A genotoxicidade da √°gua foi avaliada por meio do teste de micron√ļcleos em Tradescantia pallida var. purpurea. Em paralelo, um protocolo de avalia√ß√£o r√°pida de habitats (PARH) foi realizado, an√°lises f√≠sico-qu√≠micas, dados de uso e ocupa√ß√£o do solo e do n√ļmero de habitantes tamb√©m foram coletados e examinados para poss√≠veis rela√ß√Ķes com a genotoxicidade. N√£o houve diferen√ßa significativa na genotoxicidade ao longo do tempo para tr√™s das quatro sub-bacias estudadas. Houve rela√ß√£o significativa entre a genotoxicidade da √°gua e o n√ļmero de habitantes. Ambientes que apresentavam alta genotoxicidade, baixa qualidade h√≠drica e alta degrada√ß√£o ambiental no primeiro per√≠odo, se mantiveram na mesma condi√ß√£o no segundo per√≠odo e futuramente as √°reas mais preservadas da bacia podem vir a se assemelhar com estes ambientes

    Edge effect on vascular epiphytes in a subtropical Atlantic Forest fragment

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    Epiphytes are efficient indicators of environmental quality. The Atlantic Forest is a hotspot for epiphyte richness; however, it is experiencing one of the highest rates of degradation, exposing epiphytes to edge effects. This study aimed to evaluate the floristic composition and richness of vascular epiphytes and their relationship with phorophyte features and microenvironmental variables at the edge and in the interior of a subtropical Atlantic Forest fragment in Brazil. Twenty-five trees were analyzed, respectively, at the edge and in the interior of the fragment. Height and diameter of phorophytes, temperature, relative air humidity, photosynthetically active radiation and canopy opening were measured. A total of 41 epiphytic species were recorded, 40 occurring in the interior and 23 at the edge. Orchidaceae, Bromeliaceae, and Polypodiaceae were the richest families, representing 75% of all species. The average number of species per tree in the interior was twice that for the edge. Pleopeltis pleopeltifolia, Microgramma squamulosa, M. vacciniifolia and Rhipsalis teres concentrated great biomass in both environments, with twice as much in the interior. Epiphyte richness and biomass was lower on thinner trees with more open canopies at the edge. Our results indicate that the forest interior is more beneficial for epiphytes, which are sensitive to environmental changes caused by the edge effect. The contrast between the epiphytic communities of the edge and the interior reveals the need to increase richness and abundance of native trees and prevent cattle grazing, the planting of exotic species and more human settlements in the habitat matrix.The Atlantic Forest is a hotspot for epiphyte richness; however, it is experiencing one of the highest rates of degradation, exposing epiphytes to edge effects. This study aimed to evaluate the floristic composition and richness of vascular epiphytes and their relationship with phorophyte features and microenvironmental variables at the edge and in the interior of a subtropical Atlantic Forest fragment in Brazil. Twenty-five trees were analyzed, respectively, at the edge and in the interior of the fragment, totaling fifty individuals. The height and diameter of phorophytes, temperature, relative air humidity, photosynthetically active radiation, and canopy opening were measured. A total of 41 epiphytic species were recorded, 40 occurring in the interior and 23 at the edge. Orchidaceae, Bromeliaceae, and Polypodiaceae were the richest families, representing 75% of all species. The average number of species per tree in the interior was twice that for the edge. Pleopeltis pleopeltifolia, Microgramma squamulosa, M. vacciniifolia, and Rhipsalis teres concentrated great biomass in both environments, with twice as much in the interior. Epiphyte richness and biomass were lower on thinner trees with more open canopies at the edge. Our results indicate that the forest interior is more beneficial for epiphytes, which are sensitive to the edge effect. The contrast between the epiphytic communities of the edge and the interior reveals the need to increase the richness and abundance of native trees and prevent cattle grazing, the planting of exotic species, and more human settlements in the habitat matrix

    Prognostic Impact of LAG-3 mRNA Expression in Early Breast Cancer

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    Background: Monoclonal antibodies against PD-1 or PD-L1 have been established in clinical practice for the treatment of both early and advanced/metastatic triple-negative breast cancer. Beyond the established immune checkpoints (ICPs) (PD-1 and CTLA-4), additional ICPs, such as lymphocyte activation gene-3 (LAG-3), are subject of current research. In the present retrospective gene-expression analysis, we evaluated the prognostic significance of LAG-3 in 461 patients with early breast cancer. In addition, we examined whether there was a correlation between the different ICP and CD8 expressions. Methods: Using microarray-based gene-expression analysis, we examined the prognostic significance of LAG-3 mRNA expression for metastasis-free survival (MFS) in the whole cohort of 461 breast cancer patients and among different molecular subtypes. Correlations were analyzed using Spearman’s rho correlation coefficient. Results: In the whole cohort, LAG-3 expression had no significant impact on MFS (p = 0.712, log-rank). In the subgroup analyses, there was a trend that a higher LAG-3 expression was associated with a favorable outcome in the luminal B (p = 0.217), basal-like (p = 0.370) and HER2 (p = 0.089) subtypes, although significance was not reached. In contrast, in a multivariate Cox regression analysis, adjusted for age, tumor size, axillary nodal status, histological grade of differentiation and proliferation marker Ki-67, LAG-3 showed a significant influence on MFS (HR 0.574; 95% CI 0.369–0.894; p = 0.014). High LAG-3 significantly correlated with CD8 (ρ = 0.571; p < 0.001). Conclusions: LAG-3 expression had an independent impact on MFS. In addition to PD-1 and PD-L1, further immune checkpoints, such as LAG-3, could serve as therapeutic targets in breast cancer

    Zinc accelerates respiratory burst termination in human PMN

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    The respiratory burst of phagocytes is essential for human survival. Innate immune defence against pathogens relies strongly on reactive oxygen species (ROS) production by the NADPH oxidase (NOX2). ROS kill pathogens while the translocation of electrons across the plasma membrane via NOX2 depolarizes the cell. Simultaneously, protons are released into the cytosol. Here, we compare freshly isolated human polymorphonuclear leukocytes (PMN) to the granulocytes-like cell line PLB 985. We are recording ROS production while inhibiting the charge compensating and pH regulating voltage-gated proton channel (HV1). The data suggests that human PMN and the PLB 985 generate ROS via a general mechanism, consistent of NOX2 and HV1. Additionally, we advanced a mathematical model based on the biophysical properties of NOX2 and HV1. Our results strongly suggest the essential interconnection of HV1 and NOX2 during the respiratory burst of phagocytes. Zinc chelation during the time course of the experiments postulates that zinc leads to an irreversible termination of the respiratory burst over time. Flow cytometry shows cell death triggered by high zinc concentrations and PMA. Our data might help to elucidate the complex interaction of proteins during the respiratory burst and contribute to decipher its termination

    Removal of ammoniacal nitrogen from municipal landfill leachate with floating <i>Typha domingensis</i> (Typhaceae)

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     A promising method for the treatment of effluents is the use of floating macrophytes. Ammoniacal nitrogen is a typical compound present in urban landfill leachates and its removal is important due its toxicity to several organisms. Therefore, the study evaluated Typha domingensis survival and nitrification potential artificially floating in domestic solid waste leachate. Plants were exposed for 35 days to leachate (100, 75 and 50 %) and to rainwater with N:P:K (control). Dissolved oxygen (DO) of the treatments was periodically measured, and ammoniacal nitrogen, nitrite and nitrate were analyzed before and after exposure. At the end of the experiment, plant survival rate was calculated. After two weeks, DO increased twice in the control, three times in 50 % leachate, four times in 75 % leachate, and eight times in 100 % leachate. At the end of the experiment, ammoniacal nitrogen was no longer detected, there was a significant reduction of nitrite, and a significant increase of nitrate in the treatments containing leachate. Plant survival was higher in those individuals exposed to 100 % leachate and decreased at lower leachate concentrations: 98 %, 94 %, 92 %, and 86 %. The study demonstrated that the ammoniacal nitrogen concentration of the leachate was not toxic to T. domingensis, and that it was efficient in the removal of this compound from the effluent, indicating that the species may be used artificially floating for the removal of this contaminant from domestic solid waste landfill leachate when in low concentrations

    Biomonitors to evaluate the toxic potential of urban solid waste landfill leachate

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    The accentuated increase in the production of solid urban waste (SUW) and the consequent accumulation of leachate in landfills increase the risk of environmental contamination. Biomonitors are used to assess the toxicity of pollutants on living organisms. In this study, the pollutant potential of leachate from SUW from a deactivated landfill was evaluated by bioassays with Lactuca sativa L. and Lycopersicon esculentum Mill., and the relationship between chemical characteristics of the effluent and biological parameters was analyzed. The effluent was tested in its raw form and diluted in distilled water at concentrations of 75 and 50%. The percentage of germination, root growth (RG), mitotic index (MI), chromosomal abnormalities index (CAI), and micronuclei frequency (MCN) were analyzed. In the presence of effluent, germination and MI decreased, while RG, CAI and MCN frequencies increased in relation to the negative control (distilled water) for both species. Lead, iron and zinc presented negative relation with seed germination for both species, with RG of L. sativa and MI of L. esculentum, as well as a positive relation with MCN frequency in the studied species. Because of its larger chromosomes, L. sativa is a more suitable biomonitor of SUW leachate toxicity than L. esculentum. Even though the landfill is deactivated, it is necessary to treat this effluent, in order to minimize environmental impacts

    AVALIA√á√ÉO DO POTENCIAL GENOT√ďXICO DE C√ĀDMIO E CHUMBO POR MEIO DO BIOENSAIO COM Tradescantia pallida (Rose) D.R. Hunt var. purpurea Boom

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    O potencial genot√≥xico dos elementos-tra√ßo c√°dmio (Cd) e chumbo (Pb) nas concentra√ß√Ķes m√°ximas permitidas no Brasil pelas Resolu√ß√Ķes CONAMA n¬ļ 357/2005 (classifica√ß√£o de corpos d‚Äô√°gua, √°gua doce de classe I) e CONSEMA n¬ļ 355/2017 (emiss√£o de efluentes l√≠quidos em √°guas superficiais no Rio Grande do Sul) foi avaliado por meio do teste de micron√ļcleos (MCN) com o uso de Tradescantia pallida var. purpurea. Ap√≥s 24 h de adapta√ß√£o em √°gua destilada, 20 ramos com bot√Ķes florais foram expostos por 8 h em 2 L em √°gua destilada com diferentes concentra√ß√Ķes de Cd (0,001 e 0,1 mg L-1) e Pb (0,01 e 0,2 mg L-1), seguido da recupera√ß√£o por 24 h em √°gua destilada para finalizar o ciclo da meiose. Simultaneamente, foi realizado controle negativo com exposi√ß√£o dos ramos apenas em √°gua destilada. Ap√≥s, as infloresc√™ncias foram fixadas em etanol/√°cido ac√©tico (3:1 v:v) por 24 h e armazenadas em etanol 70% sob refrigera√ß√£o. As frequ√™ncias de MCN nos bot√Ķes florais expostos √†s concentra√ß√Ķes de 0,001 mg L-1 e 0,1 mg L-1 de Cd n√£o diferiram significativamente entre si (2,90 e 3,43 MCN, respectivamente), mas diferiram significativamente da frequ√™ncia do controle (1,93 MCN) (p=0,006). Para Pb, as frequ√™ncias de MCN nos bot√Ķes florais expostos √†s concentra√ß√Ķes 0,01 mg L-1 e 0,2 mg L-1 diferiram significativamente entre si (3,76 e 5,03 MCN, respectivamente) e do controle (1,93 MCN) (p&lt;0,001). Os resultados indicam que as concentra√ß√Ķes m√°ximas de Cd e Pb permitidas pelas Resolu√ß√Ķes CONAMA n¬ļ 357/2005 e CONSEMA n¬ļ 355/2017 s√£o potencialmente genot√≥xicas.Palavras-chave: Genotoxicidade. Elemento-tra√ßo. Trad-MCN.ABSTRACTThe genotoxic potential of the trace elements cadmium (Cd) and lead (Pb) at the maximum concentrations allowed by CONAMA n¬ļ 357/2005 (classification of watersheds, class 1 freshwater) and CONSEMA n¬ļ 355/2017 resolutions (emission of effluents in superficial waters in Rio Grande do Sul) were evaluated using the micronuclei (MCN) test with the use of Tradescantia pallida var. purpurea. After 24 h of adaptation in distilled water, 20 cuttings with floral buds were exposed for 8 h in 2 L in distilled water with different concentrations of Cd (0.001 and 0.1 mg L-1) and Pb (0.01 and 0.2 mg L-1), followed by recovery for 24 h in distilled water to finish the meiosis cycle. Simultaneously, negative control was performed with exposure of the cuttings only in distilled water. After the inflorescences were fixed in ethanol/acetic acid (3:1 v:v) for 24 h and stored in ethanol 70% under refrigeration. MCN frequencies in flower buds exposed to concentrations of 0.001 mg L-1 and 0.1 mg L-1 of Cd did not differ significantly from each other (2.90 and 3.43 MCN, respectively), but differed significantly from the control (1.93) (p=0.006). For Pb, the MCN frequency in flower buds exposed to concentrations of 0.01 mg L-1 and 0.2 mg L-1 differed significantly from each other (3.76 and 5.03, respectively) and from the control (1.93) (p&lt;0.001). The results indicate that the maximum concentrations of Cd and Pb permitted by CONAMA n¬į 357/2005 and CONSEMA n¬į 355/2017 resolutions are potentially genotoxic.Keywords: Genotoxicity. Trace element. Trad-MCN
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