Search

Mining activity is one of the main responsible for accumulation of potentially toxic elements in the environment. These contaminants are absorbed by plants served as food that could be a risk to human health, such rice. Rice is a staple food with known accumulation of toxic elements. The recent collapse of a mining dam operated by Samarco Mining Company spilled around 50 million m3 of Fe-mining waste in the environment, including rivers and farming areas. In the present study, concentrations of As, Cd, Hg, Pb, Co, Zn, Mn, Cu, Fe, Al, Se, and Sr were determined in soils, roots and grains of rice plants cultivated in soil containing Samarco's residual mud (0, 16, 34 and 50%). Further, rice plant agronomic parameters (chlorophyll, carotenoids, grain yield, mass, height) were assessed. Rice cultivated at Samarco's residual mud produced grains with low levels of As, Cd and Pb. However, the excess of mud (50%) during the rice cultivation reduced roots' growth and grains yield. Chlorophyll (a and b) and carotenoids contents were significantly lower in all mud cultivations, mainly mud-50%. Our findings suggest that plant alterations induced by the mud were associated to the deficiency of nutrients and the physical properties of the mud. Soil fertilization by organic matter and top soil provided conditions for plant development. Therefore, considering the experimental conditions here used, we showed that is possible the use of the affected land for agriculture and reforestation after soil amendment.

Concentrations of As, Cd, Co, Cu, Mn, Pb, Se and Zn were determined in polished and husked rice samples purchased from Singapore markets to estimate nutritional risk by their estimated weekly intakes (EWIs). The elemental distribution in rice grain was studied using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), and a principal component analysis was performed to investigate the relationships between the variables (total element concentration) in a multidimensional space. Except for Cd and Se, the median concentration of analytes for husked grains was higher than in polished grains. Rice samples with As concentration higher than 198 μg kg−1 were submitted to speciation analysis, and inorganic-As found in grains ranged from 41 to 87 % of the total As. Calculated EWIs for essential elements were lower than the Recommended Dietary Allowance, while the EWIs for non-essential elements were below the Provisional Tolerable Weekly Intake. Nevertheless, our results demonstrate that the presence of toxic elements in rice, especially As, must be carefully monitored. It was found a significantly low concentration levels of essential elements in most of the samples analyzed, highlighting the relevance of biofortification strategies to mitigate hidden hunger. Furthermore, the mineral profile obtained from the samples allowed discrimination of rice samples according to farming practice, grain processing and country of origin using principal component analysis and discriminant function analysis.

Change in cell morphogenesis is an important feature for proper development of eukaryotes. It is necessary for cell polarity and asymmetry and is essential for asymmetric cell division. RAM/MOR is a conserved signaling network that coordinates cell polarity determinants important for asymmetric cell division and cell polarity establishment. Mo25 is a scaffold protein that acts as a master regulator of the germinal center kinase (GCK) which triggers the downstream signaling of this network. Little is known about RAM/MOR network or Mo25 protein homologs in plants. Here, we provide a glimpse of the evolutionary gene history of Mo25 in green plants. Our data showed that a duplication of Mo25 occurred at the basis of land plants (Embryophyta), forming the groups Mo25A and Mo25B. Further duplication events occurred in other plant lineages and one subgroup of sequences seemed to be rapidly diverging. This subgroup contained an A. thaliana paralog (AtMo25-1) which lacks intron and is expressed in a similar fashion of retrogenes (i.e. low expression levels and narrow expression breadth), suggesting that this paralog was duplicated by retroposition. We also showed that all AtMo25 proteins are structurally similar to each other and to the human homolog, although differences in residues in the interface between human Mo25 and MST3 are observed in the A. thaliana homologs. Expression profile of AtMo25 homologs suggest that they are required at different developmental contexts, possibly interacting with different partners. Finally, we discuss whether Mo25 duplication in Embryophyta could be an evolutionary novelty important for the terrestrial environment conquest and whether the duplicated paralogs are undergoing neo- or subfunctionalization.

Several Brazilian sugarcane varieties have the ability to grow with little addition of inorganic nitrogen fertilizers, showing high contributions of Biological Nitrogen Fixation (BNF). A particular type of nitrogen-fixing association has been described in this crop, where endophytic diazotrophs such as Gluconacetobacter diazotrophicus and Herbaspirillum spp. colonize plant tissues without causing disease symptoms. In order to gain insight into the role played by the sugarcane in the interaction between this plant and endophytic diazotrophs, we investigated gene expression profiles of sugarcane plants colonized by G. diazotrophicus and H. rubrisubalbicans by searching the sugarcane expressed sequence tag SUCEST Database (http://sucest.lad.ic.unicamp.br/en/). We produced an inventory of sugarcane genes, candidates for exclusive or preferential expression during the nitrogen-fixing association. This data suggests that the host plant might be actively involved in the establishment of the interaction with G. diazotrophicus and H. rubrisubalbicans.Diversos genótipos brasileiros de cana-de-açúcar são capazes de crescer com baixa adição de adubos nitrogenados, obtendo elevadas contribuições da Fixação Biológica de Nitrogênio (FBN). Um tipo especial de associação com bactérias fixadoras de nitrogênio foi descrito em cana-de-açúcar, onde as bactérias endofíticas, como Gluconacetobacter diazotrophicus e Herbaspirillum spp., colonizam o interior dos tecidos vegetais, sem causar sintomas de doença. Com o objetivo de tentar entender o papel da cana-de-açúcar nesse tipo de associação, nós investigamos os perfis de expressão gênica de plantas colonizadas pelos diazotróficos endofíticos, usando o banco de dados do SUCEST. Um catálogo com os genes de cana-de-açúcar que são candidatos a se expressar exclusivamente ou preferencialmente durante a associação foi gerado. Esses dados preliminares sugerem que a cana-de-açúcar deve ter uma participação ativa na interação, respondendo a diversos processos metabólicos durante a associação.

Infections caused by Staphylococcus aureus – particularly nosocomial infections - represent a great concern. Usually, the early stage of pathogenesis consists on asymptomatic nasopharynx colonization, which could result in dissemination to other mucosal niches or invasion of sterile sites, such as blood. This pathogenic route depends on scavenging of nutrients as well as binding to and disrupting extracellular matrix (ECM). Manganese transport protein C (MntC), a conserved manganese-binding protein, takes part in this infectious scenario as an ion-scavenging factor and surprisingly as an ECM and coagulation cascade binding protein, as revealed in this work. This study showed a marked ability of MntC to bind to several ECM and coagulation cascade components, including laminin, collagen type IV, cellular and plasma fibronectin, plasminogen and fibrinogen by ELISA. The MntC binding to plasminogen appears to be related to the presence of surface-exposed lysines, since previous incubation with an analogue of lysine residue, ε-aminocaproic acid, or increasing ionic strength affected the interaction between MntC and plasminogen. MntC-bound plasminogen was converted to active plasmin in the presence of urokinase plasminogen activator (uPA). The newly released plasmin, in turn, acted in the cleavage of the α and β chains of fibrinogen. In conclusion, we describe a novel function for MntC that may help staphylococcal mucosal colonization and establishment of invasive disease, through the interaction with ECM and coagulation cascade host proteins. These data suggest that this potential virulence factor could be an adequate candidate to compose an anti-staphylococcal human vaccine formulation.

International audience; In multicellular organisms, organogenesis requires a tight control of the balance between cell division and cell differentiation. Distinct signalling pathways that connect both cellular processes with developmental cues might have evolved to suit different developmental plans. Here, we identified and characterized a novel protein that interacts with pre-replication complex (pre-RC) subunits, designated Armadillo BTB Arabidopsis protein 1 (ABAP1). Overexpression of ABAP1 in plants limited mitotic DNA replication and decreased cell proliferation in leaves, whereas ABAP1 downregulation increased cell division rates. Activity of ABAP1 in transcription was supported by its association with the transcription factor AtTCP24. The ABAP1–AtTCP24 complex bound specifically to the promoters of AtCDT1a and AtCDT1b in vitro and in vivo. Moreover, expression levels of AtCDT1a and AtCDT1b were reduced in ABAP1-overexpressing plants and they were increased in plants with reduced levels of ABAP1. We propose that ABAP1 participates in a negative feedback loop regulating mitotic DNA replication during leaf development, either by repressing transcription of pre-RC genes and possibly by regulating pre-RC utilization through direct association with pre-RC components.

Cana-de-açúcar é uma planta agrícola com grande importância econômica para o Brasil. Os cultivares modernos de cana-de-açúcar apresentam uma alta complexidade genômica, devido ao seu genoma ser poliploide e com número cromossômico variando entre 100-120. As plantas de cana-de-açúcar estão sujeitas ao ataque de diversos tipos de patógenos, e sua tolerância depende da ação de genes de resistência. Estes podem desencadear uma cascata de reações ou interagir diretamente com uma molécula efetora, resultando em tolerância por parte da planta à presença do patógeno. O genoma dos cultivares moderno apresentam inúmeros elementos de transposição posicionados em diferentes regiões do genoma. Devido a essa abundância, os elementos de transposição estão sendo usados como marcadores moleculares, por exemplo, RBIP (Retrotransposon-Based Insertion Polymorphism), que identifica polimorfismos baseado na inserção de elementos do tipo retrotransposons. Esta técnica é capaz de diferenciar a presença e a ausência de um elemento de transposição em uma determinada região do genoma. Para a aplicação em organismos poliploides foi desenvolvida a técnica RBIP-qPCR, permitindo dosar a presença e ausência de um elemento de transposição em um organismo poliploide. Sendo assim este trabalho tem como objetivo aplicar a técnica de RBIP-qPCR em elementos de transposição alocados adjacentes a genes de resistência a fim de, posteriormente, verificar a existência de associação entre genes de resistência e elementos de transposição. Para isso foram analisadas três famílias de genes de resistência, I2C-2, Xa21 e Pti1. Foram realizadas análises de composição genômica de cada uma das regiões, genômica comparativa entre as variedades de R570 e SP80-3280 para a região genômica que contém o gene I2C-2, além de uma análise de expressão de genes e elementos de transposição vizinhos neste loco. A partir destes estudos foi possível selecionar um elemento de transposição, scDEL 5.1, para aplicar a técnica de RBIP-qPCR. Os resultados das análises de reconhecimento do ambiente genômico determinou a escolha de um elemento para aplicação da técnica. Verificamos que na ausência de scDEL 5.1 a metodologia RBIPqPCR foi eficaz em todos os genomas testados. As análises de presença de scDEL 5.1 no loco revelaram que elementos com elevado número de cópias no genoma não são adequados para a aplicação da metodologia. Sugarcane is an agricultural plant with great economic importance for Brazil. The modern cultivars of sugarcane present a high genomic complexity, due to their genome being polyploid and with chromosome number varying between 100-120. Sugarcane plants are targets of several types of pathogens, and their tolerance depends on the action of resistance genes. These can trigger a cascade of reactions or interact directly with an effector molecule, resulting in tolerance by the plant to the presence of the pathogen. The genome of modern cultivars presents several transposable elements allocated in different regions of the genome. Due to this abundance, transposable elements are being used as molecular markers, such as RBIP (Retrotransposon-Based Insertion Polymorphism), which identifies polymorphisms based on the insertion of retrotransposon. This technique is able to differentiate the presence and absence of a transposable element in a particular region of the genome. For the application in polyploid organisms the RBIP-qPCR technique was developed, allowing measuring the presence and absence of a transposable element in a polyploid organism. Therefore, the objective of this work is to apply the RBIP-qPCR technique to on a transposable element localized adjacent to resistance genes in order to, latterly, verify the existence of association between resistance genes and transposable elements. For this, three families of resistance genes, I2C-2, Xa21 and Pti1 were analyzed. Genomic composition analyzes of each region, comparative genomics between the R570 and SP80-3280 varieties for the genomic region containing the I2C-2 gene, as well as an analysis of genes and elements expression neighbors at this locus were performed. From these studies it was possible to select a transposition element, scDEL 5.1, to apply the RBIP-qPCR technique. The results of the genomic environment recognition analysis determined the choice the transposable element for the application of the technique. We verified that in the absence of scDEL 5.1 the RBIP-qPCR methodology was effective in all genomes tested. Analysis of the presence of scDEL 5.1 in the locus revealed that elements with high copy number in the genome are not suitable for the application of the methodology.

Classical Morphology in Plant Sciences requires a typological view of plant organs. This usually implies in classifying stem, leaf and root as basic and well-defined unities. Ferns are the most diverse group of non-flowering plants and occupy a key position in the land plants phylogeny. Their leaves are usually understood as homologous to those of seed-plants. Still, they bear intriguing features, like a leaf apical meristem bearing a distinct apical cell, and that may be many times divided, resembling the activity of a whole shoot. We present a study about the leaf development in some leptosporangiate ferns of different morphologies to better understand how these structures may have evolved and the possible homologies between their ontogenetic processes. Class I KNOX genes expression was analyzed in the heteroblastic fern Mickelia scandens, as they are related to organ determinacy in angiosperms. The two copies of Class I KNOX are expressed even in determined structures, like pinnae. But a reduction of the quantity of transcript is related to the development of the less determinate frond form that occurs in terrestrial individuals. Using classic anatomical tools, we studied the development of leaves in ferns related to Mickelia scandens that present different morphologies. In addition, we observed natural occurring mutants in a collection. The basic structure of apical cells is essentially well conserved in all the group. Marginal cells, classically pointed as part of the marginal meristem, may repeat in some degree the activity of the leaf apical cell. Changes in the structure and activity of these structures may be the reason why simple-leaved ferns of the genus Elaphoglossum do not make compound leaves and why usual leaf morphology may change, producing anomalous structures. We discuss this data based on Agnes Arber concepts of partial-shoot and identity-in-parallel, proposing an interpretation of the fern leaf not as a well-defined organ, but a product of ontogenetic processes, some of them typical of the shoot A Morfologia Clássica em Botânica requer uma visão tipológica dos órgãos vegetais. Isso geralmente implica na classificação de caule, folha e raiz como unidades básicas e bem definidas. Samambaias são o grupo mais diverso de plantas sem flores e ocupam uma posição-chave na filogenia das plantas terrestres. Suas folhas geralmente são entendidas como homólogas às de espermatófitas. Ainda assim, possuem características intrigantes, como um meristema apical foliar com uma célula apical distinta, e podem ser muitas vezes divididas, lembrando a atividade de um sistema caulinar. Apresentamos um estudo do desenvolvimento foliar em algumas samambaias leptosporangiadas de diferentes morfologias para entender melhor como essas estruturas podem ter evoluído e as possíveis homologias entre seus processos ontogênicos. A expressão dos genes de Classe I KNOX foi analisada na samambaia heteroblástica Mickelia scandens, uma vez que estão relacionados à determinação de órgãos em angiospermas. As duas cópias de Classe I KNOX são expressas mesmo em estruturas determinadas, como pinas. Mas uma redução da quantidade de transcritos está relacionada ao desenvolvimento da forma menos determinada da fronde que ocorre em indivíduos terrestres. Usando ferramentas anatômicas clássicas, estudamos o desenvolvimento de folhas em samambaias relacionadas a Mickelia scandens que apresentam diferentes morfologias. Além disso, observamos mutantes de ocorrência natural em uma coleção. A estrutura básica das células apicais é essencialmente bem conservada em todo o grupo. Células marginais, classicamente apontadas como parte do meristema marginal, podem repetir em certo grau a atividade da célula apical da folha. Mudanças na estrutura e atividade dessas estruturas podem ser a razão pela qual a samambaia de folhas simples do gênero Elaphoglossum não fazem folhas compostas e porque a morfologia de uma folha normal pode ser alterada, produzindo estruturas anômalas. Discutimos esses dados com base em conceitos de Agnes Arber de sistema caulinar-parcial identidade-em-paralelo, propondo uma interpretação da folha de samambaia não como um órgão bem definido, mas como um produto de processos de ontogênese, alguns deles típicos do sistema caulinar

Folhas apresentam grande diversidade morfológica como resultado de diferentes padrões de desenvolvimento. Embora a forma plana das folhas típicas seja eficiente para sua função de fotossíntese, algumas espécies de Aizoaceae também desenvolveram folhas teretes, com simetria radial e lâmina abaxializada. Para entender os mecanismos de desenvolvimento responsáveis pela geração desses padrões, investigamos a ontogênese de folhas com diferentes morfologias no grupo. Neste trabalho, descrevemos o desenvolvimento foliar em espécies de Aizoaceae, incluindo indivíduos com folhas planas e teretes, utilizando as técnicas usuais de anatomia vegetal. Todas as espécies analisadas têm folhas com base bifacial estabelecida em estágios iniciais de desenvolvimento; no entanto, as espécies com folhas de terete possuem lâminas unifaciais. Com interesse no papel do gene ARP recente duplicado em Aizoaceae, nós investigamos a possível correlação entre o evento de duplicação e o surgimento da morfologia da folha abaxializada em Aizoaceae. Detectamos, por meio de hibridização in situ, que ARP é expresso em todo o primórdio foliar, sugerindo que, em Aizoaceae, este gene está envolvido principalmente na determinação do destino das células foliares. Além disso, demonstramos que a expressão dos ortólogos de ARP em Aizoaceae são capazes de recuperar o fenótipo selvagem de Arabidopsis as1, indicando um alto grau de conservação funcional do gene, mesmo em folhas com uma morfologia tão distinta Leaves exhibit great morphological diversity as a result of different patterns of development. Although the flat shape of typical leaves is efficient for their photosynthesis function, some Aizoaceae species have also evolved terete leaves, with radial symmetry and abaxialized lamina. In order to understand the development mechanisms responsible for generating such patterns, we investigate the ontogenesis of leaves with different morphologies in the group. In this work, we describe development in Aizoaceae species, including individuals with flat and terete leaves, processed according to usual techniques in plant anatomy. We found that all species have leaves with bifacial base established in early stages of development; however, terete leaved species have unifacial leaf blades. Interested in the role of the recent duplicated ARP gene in Aizoaceae, we investigate the possible correlation between the duplication event and the emergence of the abaxialized leaf morphology in Aizoaceae. We detected, by in situ hybridization assays, that ARP is expressed throughout the leaf primordium, suggesting that in Aizoaceae this gene is involved in the determination of leaf cell fate. In addition, we have shown that the expression of ARP orthologs of Aizoaceae is capable of recovering the wild-type phenotype of Arabidopsis as1, indicating a high degree of functional conservation of the gene, even in leaves with such a distinct morphology

Cubatão, o maior pólo industrial da américa latina também já foi uma das cidades mais poluídas do mundo. Os 30 anos de intensa atividade industrial vêm pressionando o meio ambiente com substâncias tóxicas e afetando gravemente a saúde da população. Dentre as substâncias contaminantes mais importantes da região estão os derivados de petróleo como o benzeno, tolueno, etilbenzeno e xilenos. Conhecidos como BTEX, eles são produzidos e utilizados em larga escala e a contaminação ocorre frequentemente através de vazamentos. Nos solos, devido à sua solubilidade em água, essas substâncias podem se espalhar por longas distâncias a partir do ponto afetado contaminando locais distantes. Já foi comprovada a capacidade de micro-organismos de sobreviver e até utilizar BTEX como fonte de carbono. Os micro-organismos adaptados catabolizam os contaminantes transformando-os em substâncias menos tóxicas e até mesmo eliminando-os do ambiente, capacidade de grande interesse econômico e ambiental. Nessa linha, nossa proposta visa o estudo das comunidades microbianas de solos afetados e não afetados por BTEX. Para isso foi utilizada a metagenômica como abordagem de estudo identificando-se diferenças qualitativas e quantitativas nas estruturas microbianas de três diferentes locais do município de Cubatão, sendo um deles afetado diretamente por BTEX. Pelo método utilizado e aqui desenvolvido, foi possível identificar um panorama metabólico geral identificando-se genes relevantes e o potencial de degradação de hidrocarbonetos aromáticos de micro-organismos conhecidos e desconhecidos, revelando melhor o potencial metabólico dos solos identificados. Os resultados apresentados podem contribuir para um melhor entendimento da dinâmica in situ de uma comunidade microbiana afetada por BTEX assim como melhorar o conhecimento sobre a comunidade microbiana de um local altamente impactado como Cubatão. Cubatão is the largest industrial site in Latin America and was in the past one of the most polluted cities in the world. 30 years of intense industrial activity has pushed environmental limits with toxic substances and has severely affected the inhabitants\' health. Among the contaminants found in the region, the petroleum derivatives benzene, toluene, ethylbenzene and xylenes are the most important. Known collectively as BTEX, they are produced and used at a large scale and contamination frequently occurs. Because it is highly soluble in water, when in soil BTEX can spread long distances from the original contamination site, thus affecting large areas. Some microorganisms are known to live in contaminated environments and use contaminants such as BTEX as a unique carbon source for energy production. They catabolize contaminants into less dangerous products or even eliminate them from environment, a feature which has great commercial and environmental interest. We therefore compared the microbial communities in soils which were affected and un-affected by BTEX contamination. To this end, we used a metagenomics approach and developed a comparison method to identify microorganisms and degradation potential of soils studied. We found qualitative and quantitative differences in microbial structures from three different sites in Cubatão County, one of which is contaminated with BTEX. We constructed a metabolic overview identifying important genes, degradation potential and microorganisms related to BTEX degradation. The results presented here could contribute to understanding the in situ dynamics of a BTEX affected microbial community as well as improving our knowledge of the microbial community of Cubatão, a highly environmentally impacted place.