Uma classificação f��sico-h��drica dos solos

�� proposto um sistema de classificação de solos baseado na capacidade de aera����o e de hidrata����o dos perfis. A hidrata����o �� medida pela ��gua dispon��vel (capacidade de campo menos ponto de murcha), enquanto a aera����o �� avaliada pela conjuga����o dos valores de ar dispon��vel (porosidade total menos capacidade de campo) e de velocidade de infiltra����o b��sica. A partir desses pressupostos, s��o definidas 10 ordens e 28 classes de solos. As vari��veis de entrada s��o: densidade das part��culas, densidade do solo, porosidade total, capacidade de campo, ponto de murcha e velocidade de infiltra����o b��sica. A classificação �� baseada em crit��rios estritamente num��ricos e inexistem componentes subjetivos de avalia����o. As nove ordens principais, cada uma com tr��s classes, s��o: solos aerado-aq����feros (I); solos aerado-mesaq����feros (II); solos mesaerado-aq����feros (III); solos mesaerado-mesaq����feros (IV); solos aerado-aq����cludos (V); solos mesaerado-aq����cludos (VI); solos anaerado-aq����feros (VII); solos anaerado-mesaq����feros (VIII); solos anaerado-aq����cludos (IX). Uma ��ltima ordem �� poss��vel (ordem X), a ordem dos solos alagados, com apenas uma classe. �� feita uma aplica����o do m��todo em solos com classes texturais variadas, desde areias at�� solos muito argilosos. Demonstra-se que inexiste uma rela����o direta entre as classes texturais e as classes ou ordens de solo do sistema. Com a conjuga����o de outras informa����es (meteorol��gicas, fitol��gicas, topogr��ficas, de n��vel de manejo), prop��e-se seja o m��todo tamb��m utilizado como ferramenta de manejo dos solos ou na avalia����o de aptid��o agr��cola das terras ou no dimensionamento dos projetos de irriga����o.

Classificação de solos planoss��licos do Sert��o do Araripe (PE)

Neste trabalho objetivou-se caracterizar e classificar solos com horizonte B pl��nico subjacente a um horizonte B textural e, portanto, em posi����o n��o-diagn��stica para a classe dos Planossolos do Sistema Brasileiro de Classificação de Solos (SIBCS). Foram selecionados tr��s perfis representativos destes solos no munic��pio de Ouricuri, microrregi��o de Araripina, no Sert��o de Pernambuco, ��rea de ocorr��ncia expressiva de solos planoss��licos. Os perfis foram descritos e amostras deformadas foram coletadas de todos os horizontes para realiza����o das an��lises f��sicas e qu��micas. Amostras indeformadas foram coletadas para determina����o da densidade do solo. Os resultados mostram que os solos, formados de uma dupla contribui����o de material de origem (cobertura sedimentar e rochas cristalinas do Pr��-Cambriano), apresentam duas se����es distintas, que refletem a contribui����o dos materiais origin��rios. A se����o superior �� formada pelos horizontes A, BA, Bt e, ou, Btf, e a inferior �� formada pelos horizontes 2Btbn e 2BCn. Os horizontes da se����o superior apresentam cores cromadas, textura mais arenosa, densidade mais baixa, maior condutividade hidr��ulica e menor atividade da fra����o argila do que os horizontes da se����o inferior dos perfis, que se apresentam muito densos, pouco cromados e constituem uma barreira �� percola����o da ��gua. Prop��e-se a seguinte classificação para os perfis estudados: Plintossolo Argil��vico eutr��fico planoss��lico s��dico (perfil 1); Argissolo Amarelo eutr��fico planoss��lico sol��dico (perfil 2) e Argissolo Amarelo eutr��fico pl��ntico planoss��lico s��dico (perfil 3). Os resultados indicam a necessidade de modifica����es na conceitua����o do horizonte B pl��nico do SIBCS, para permitir o enquadramento dos solos estudados. Sugere-se a elimina����o da obrigatoriedade de ser o horizonte B pl��nico imediatamente subjacente a um horizonte A ou E, bem como da necessidade de mudan��a textural abrupta, desde que apresente transi����o abrupta que configure um fraturamento muito n��tido com o horizonte que o antecede (A, E ou Bt).

High-level molecular diversity of copper-zinc superoxide dismutase genes among and within species of arbuscular Mycorrhizal fungi.

In the ecologically important arbuscular mycorrhizal fungi (AMF), Sod1 encodes a functional polypeptide that confers increased tolerance to oxidative stress and that is upregulated inside the roots during early steps of the symbiosis with host plants. It is still unclear whether its expression is directed at scavenging reactive oxygen species (ROS) produced by the host, if it plays a role in the fungus-host dialogue, or if it is a consequence of oxidative stress from the surrounding environment. All these possibilities are equally likely, and molecular variation at the Sod1 locus can possibly have adaptive implications for one or all of the three mentioned functions. In this paper, we analyzed the diversity of the Sod1 gene in six AMF species, as well as 14 Glomus intraradices isolates from a single natural population. By sequencing this locus, we identified a large amount of nucleotide and amino acid molecular diversity both among AMF species and individuals, suggesting a rapid divergence of its codons. The Sod1 gene was monomorphic within each isolate we analyzed, and quantitative PCR strongly suggest this locus is present as a single copy in G. intraradices. Maximum-likelihood analyses performed using a variety of models for codon evolution indicated that a number of amino acid sites most likely evolved under the regime of positive selection among AMF species. In addition, we found that some isolates of G. intraradices from a natural population harbor very divergent orthologous Sod1 sequences, and our analysis suggested that diversifying selection, rather than recombination, was responsible for the persistence of this molecular diversity within the AMF population.

Cor do solo: uma abordagem da forma convencional de obten����o em oposi����o �� automatiza����o do m��todo para fins de classificação de solos

A cor �� amplamente reconhecida como uma medida prim��ria identificadora de solos. Propriedades f��sicas, qu��micas e mineral��gicas de solos podem ser derivadas de sua cor. O enquadramento de algumas classes de solos, j�� no segundo n��vel categ��rico do atual Sistema Brasileiro de Classificação de solos, requer que a cor da amostra do horizonte diagn��stico seja determinada por compara����o com os padr��es existentes na escala de Munsell. Este processo de classificação �� extremamente subjetivo e consome tempo, limitando a exatid��o, a transfer��ncia e a utiliza����o do procedimento. O principal objetivo deste trabalho foi obter a cor do solo com o m��todo convencional e com um color��metro, a fim de avaliar as poss��veis implica����es na classificação de solos. Cinco ped��logos foram convidados a classificar o matiz de 80 amostras de solo pela compara����o com a carta de Munsell. Em seguida, o matiz das amostras foi obtido com um color��metro, tamb��m na nota����o de Munsell. Pelas an��lises estat��sticas foram avaliados: coeficientes de correla����o, ��ndice de precis��o (IP), forma de agrupamento e tend��ncias m��dias entre as determina����es de matiz. Coeficientes de correla����o variando de 0,68 a 0,94 entre as determina����es de cor demonstraram que os ped��logos produziram dados que validaram o estudo. No entanto, houve confirma����o de que as medidas realizadas por ped��logos n��o coincidiram, sendo diferentes tamb��m das determina����es feitas pelo color��metro. ��ndices de Precis��o (IP) indicaram haver concord��ncia em apenas 8,75 % das determina����es em amostras ��midas e 17,5 % nas amostras secas. Ocorreram diverg��ncias na determina����o do matiz das amostras que resultariam em erros na classificação dos solos. A avalia����o das tend��ncias m��dias indicou que os pesquisadores superestimaram as determina����es de cor realizadas pelo color��metro, resultando em altera����es na classificação de solos.

Specific Silencing of the REST Target Genes in Insulin-Secreting Cells Uncovers Their Participation in Beta Cell Survival.

The absence of the transcriptional repressor RE-1 Silencing Transcription Factor (REST) in insulin-secreting beta cells is a major cue for the specific expression of a large number of genes. These REST target genes were largely ascribed to a function of neurotransmission in a neuronal context, whereas their role in pancreatic beta cells has been poorly explored. To identify their functional significance, we have generated transgenic mice expressing REST in beta cells (RIP-REST mice), and previously discovered that REST target genes are essential to insulin exocytosis. Herein we characterized a novel line of RIP-REST mice featuring diabetes. In diabetic RIP-REST mice, high levels of REST were associated with postnatal beta cell apoptosis, which resulted in gradual beta cell loss and sustained hyperglycemia in adults. Moreover, adenoviral REST transduction in INS-1E cells led to increased cell death under control conditions, and sensitized cells to death induced by cytokines. Screening for REST target genes identified several anti-apoptotic genes bearing the binding motif RE-1 that were downregulated upon REST expression in INS-1E cells, including Gjd2, Mapk8ip1, Irs2, Ptprn, and Cdk5r2. Decreased levels of Cdk5r2 in beta cells of RIP-REST mice further confirmed that it is controlled by REST, in vivo. Using siRNA-mediated knock-down in INS-1E cells, we showed that Cdk5r2 protects beta cells against cytokines and palmitate-induced apoptosis. Together, these data document that a set of REST target genes, including Cdk5r2, is important for beta cell survival.

Native homing endonucleases can target conserved genes in humans and in animal models.

In recent years, both homing endonucleases (HEases) and zinc-finger nucleases (ZFNs) have been engineered and selected for the targeting of desired human loci for gene therapy. However, enzyme engineering is lengthy and expensive and the off-target effect of the manufactured endonucleases is difficult to predict. Moreover, enzymes selected to cleave a human DNA locus may not cleave the homologous locus in the genome of animal models because of sequence divergence, thus hampering attempts to assess the in vivo efficacy and safety of any engineered enzyme prior to its application in human trials. Here, we show that naturally occurring HEases can be found, that cleave desirable human targets. Some of these enzymes are also shown to cleave the homologous sequence in the genome of animal models. In addition, the distribution of off-target effects may be more predictable for native HEases. Based on our experimental observations, we present the HomeBase algorithm, database and web server that allow a high-throughput computational search and assignment of HEases for the targeting of specific loci in the human and other genomes. We validate experimentally the predicted target specificity of candidate fungal, bacterial and archaeal HEases using cell free, yeast and archaeal assays.

Genome-wide association analysis of blood-pressure traits in African-ancestry individuals reveals common associated genes in African and non-African populations.

High blood pressure (BP) is more prevalent and contributes to more severe manifestations of cardiovascular disease (CVD) in African Americans than in any other United States ethnic group. Several small African-ancestry (AA) BP genome-wide association studies (GWASs) have been published, but their findings have failed to replicate to date. We report on a large AA BP GWAS meta-analysis that includes 29,378 individuals from 19 discovery cohorts and subsequent replication in additional samples of AA (n = 10,386), European ancestry (EA) (n = 69,395), and East Asian ancestry (n = 19,601). Five loci (EVX1-HOXA, ULK4, RSPO3, PLEKHG1, and SOX6) reached genome-wide significance (p < 1.0���� 10(-8)) for either systolic or diastolic BP in a transethnic meta-analysis after correction for multiple testing. Three of these BP loci (EVX1-HOXA, RSPO3, and PLEKHG1) lack previous associations with BP. We also identified one independent signal in a known BP locus (SOX6) and provide evidence for fine mapping in four additional validated BP loci. We also demonstrate that validated EA BP GWAS loci, considered jointly, show significant effects in AA samples. Consequently, these findings suggest that BP loci might have universal effects across studied populations, demonstrating that multiethnic samples are an essential component in identifying, fine mapping, and understanding their trait variability.

Meta-analysis of estrogen response in MCF-7 distinguishes early target genes involved in signaling and cell proliferation from later target genes involved in cell cycle and DNA repair.

ABSTRACT: BACKGROUND: Many studies have been published outlining the global effects of 17 beta-estradiol (E2) on gene expression in human epithelial breast cancer derived MCF-7 cells. These studies show large variation in results, reporting between ~100 and ~1500 genes regulated by E2, with poor overlap. RESULTS: We performed a meta-analysis of these expression studies, using the Rank product method to obtain a more accurate and stable list of the differentially expressed genes, and of pathways regulated by E2. We analyzed 9 time-series data sets, concentrating on response at 3-4 hrs (early) and at 24 hrs (late). We found >1000 statistically significant probe sets after correction for multiple testing at 3-4 hrs, and >2000 significant probe sets at 24 hrs. Differentially expressed genes were examined by pathway analysis. This revealed 15 early response pathways, mostly related to cell signaling and proliferation, and 20 late response pathways, mostly related to breast cancer, cell division, DNA repair and recombination. CONCLUSIONS: Our results show that meta-analysis identified more differentially expressed genes than the individual studies, and that these genes act together in networks. These results provide new insight into E2 regulated mechanisms, especially in the context of breast cancer.

Genes encoding tumor necrosis factor alpha and granzyme A are expressed during development of autoimmune diabetes.

Progressive destruction of the insulin-producing beta cells in nonobese diabetic mice is observed after infiltration of the pancreas with lymphocytes [Makino, S., Kunimoto, K., Muraoka, Y., Mizushima, Y., Katagiri, K. & Tochino, Y. (1980) Exp. Anim. (Tokyo) 29, 1-13]. We show that the genes for tumor necrosis factor alpha and granzyme A, a serine protease associated with cytoplasmic granules of cytotoxic cells, are expressed during the development of spontaneous diabetes mellitus in the nonobese diabetic mouse. Granzyme A-positive cells are found both in and surrounding the islets, implying induction prior to islet infiltration. Tumor necrosis factor alpha expression is exclusively observed in the intra-islet infiltrate, predominantly in lymphocytes adjacent to insulin-producing beta cells, the targets of the autoimmune destruction, implying that tumor necrosis factor alpha expression is induced locally--i.e., in the islet. A considerable portion of cells expressing tumor necrosis factor alpha appear to be CD4+ T cells. This T-cell subset was previously shown to be necessary for development of the disease. Thus, these findings may be important for understanding the pathogenesis of autoimmune diabetes mellitus and potentially also for that of other T-cell-mediated autoimmune diseases.

Construction and Quantitative Evaluation of a Dual Specific Promoter System for Monitoring the Expression Status of Stra8 and c-kit Genes.

Applications of genetic constructs with multiple promoters, which are fused with reporter genes and simultaneous monitoring of various events in cells, have gained special attention in recent years. Lentiviral vectors, with their distinctive characteristics, have been considered to monitor the developmental changes of cells in vitro. In this study, we constructed a novel lentiviral vector (FUM-M), containing two germ cell-specific promoters (Stra8 and c-kit), fused with ZsGreen and DsRed2 reporter genes, and evaluated its efficiency in different cells following treatments with retinoic acid and DMSO. Several cell lines (P19, GC-1 spg and HEK293T) were transduced with this vector, and functional capabilities of the promoters were verified by flow cytometry and quantitative RT-PCR. Our results indicate that FUM-M shows dynamic behavior in the presence and absence of extrinsic factors. A correlation was also observed between the function of promoters, present in the lentiviral construct and the endogenous level of��the Stra8 and c-kit mRNAs in the cells. In conclusion, we recommend this strategy, which needs further optimization of the constructs, as a beneficial and practical way to screen chemical inducers involved in cellular differentiation toward germ-like cells.

Transcription factor CTF1 acts as a chromatin domain boundary that shields human telomeric genes from silencing.

Telomeres are associated with chromatin-mediated silencing of genes in their vicinity. However, how epigenetic markers mediate mammalian telomeric silencing and whether specific proteins may counteract this effect are not known. We evaluated the ability of CTF1, a DNA- and histone-binding transcription factor, to prevent transgene silencing at human telomeres. CTF1 was found to protect a gene from silencing when its DNA-binding sites were interposed between the gene and the telomeric extremity, while it did not affect a gene adjacent to the telomere. Protein fusions containing the CTF1 histone-binding domain displayed similar activities, while mutants impaired in their ability to interact with the histone did not. Chromatin immunoprecipitation indicated the propagation of a hypoacetylated histone structure to various extents depending on the telomere. The CTF1 fusion protein was found to recruit the H2A.Z histone variant at the telomeric locus and to restore high histone acetylation levels to the insulated telomeric transgene. Histone lysine trimethylations were also increased on the insulated transgene, indicating that these modifications may mediate expression rather than silencing at human telomeres. Overall, these results indicate that transcription factors can act to delimit chromatin domain boundaries at mammalian telomeres, thereby blocking the propagation of a silent chromatin structure.

Isolation and characterization of major histocompatibility complex (MHC) class II B genes in the Barn owl (Aves: Tyto alba)

We isolated major histocompatibility complex class II B (MHCIIB) genes in the Barn owl (Tyto alba). A PCR-based approach combined with primer walking on genomic and complementary DNA as well as Southern blot analyses revealed the presence of two MHCIIB genes, both being expressed in spleen, liver, and blood. Characteristic structural features of MHCIIB genes as well as their expression and high non-synonymous substitution rates in the region involved in antigen binding suggest that both genes are functional. MHC organization in the Barn owl is simple compared to passerine species that show multiple duplications, and resembles the minimal essential MHC of chicken.

Caracteriza����o e classificação de cambissolos do arquip��lago de Fernando de Noronha, Pernambuco

Este trabalho visou caracterizar e classificar Cambissolos de ocorr��ncia comum no Arquip��lago de Fernando de Noronha, com o objetivo de testar e contribuir para o desenvolvimento do Sistema Brasileiro de Classificação de Solos (SiBCS). Al��m disso, uma melhor compreens��o desses solos e de sua distribui����o na paisagem �� de grande import��ncia no planejamento do uso da terra, para nortear a����es governamentais visando �� explora����o sustent��vel desse complexo tur��stico-ecol��gico. Com base no Mapa Detalhado de Solos do Arquip��lago de Fernando de Noronha, seis perfis de Cambissolos representativos da ��rea foram selecionados, descritos e coletados, visando �� caracteriza����o morfol��gica, f��sica, qu��mica e mineral��gica. Os Cambissolos foram adequadamente classificados segundo a nova vers��o do SiBCS, que incluiu o grande grupo "Ta eutrof��rrico", sugerido durante o desenvolvimento deste trabalho. Os solos do Arquip��lago refletem nas suas propriedades as caracter��sticas marcantes do material de origem vulc��nico, do clima tropical com franco dom��nio oce��nico e do relevo. Os Cambissolos H��plicos Ta eutrof��rricos t��picos ocupam as posi����es mais preservadas do planalto central da ilha principal e possuem os melhores atributos f��sicos e qu��micos para utiliza����o agr��cola ou geot��cnica. Os Cambissolos H��plicos Ta eutr��ficos l��pticos, relacionados com relevos acidentados e geralmente associados com Neossolos Lit��licos e afloramentos de rocha, s��o solos que requerem prote����o especial devido �� sua alta instabilidade ao processo erosivo. Por sua vez, os Cambissolos H��plicos S��dicos vertiss��licos, que ocorrem em ��reas ligeiramente rebaixadas do planalto central, apresentam s��rios problemas de drenagem e argilas expansivas. Quimicamente, os solos apresentam teores elevados a extremamente elevados de P extra��vel, de distribui����o irregular tanto entre perfis como nos horizontes, o que sugere a influ��ncia de fontes distintas deste elemento.

Caracteriza����o e classificação de plintossolos no Munic��pio de Pinheiro-MA

Objetivou-se neste trabalho caracterizar e classificar quatro Plintossolos localizados no munic��pio de Pinheiro-MA, de forma a validar novas classes propostas no Sistema Brasileiro de Classificação de Solos (SiBCS). Foram selecionados quatro pedons em pontos distintos da paisagem: ter��o superior, m��dio, inferior e base da encosta, tendo como material de origem arenitos ferruginosos da Forma����o Itapecuru e sedimentos coluviais e aluviais. Os perfis foram morfologicamente descritos e os horizontes avaliados quanto ��s propriedades f��sicas, qu��micas e mineral��gicas. Os tr��s perfis localizados ao longo da encosta foram classificados como Plintossolos Argil��vicos, e o situado na transi����o para a v��rzea, como Plintossolo H��plico. Tr��s perfis apresentaram car��ter concrecion��rio no perfil de solo, identificando os solos como petropl��nticos no quarto n��vel categ��rico. Todos os solos apresentaram car��ter al��tico, indicando ambiente de forma����o de solos diferenciado nesta localidade do Estado do Maranh��o, que favorece a preserva����o de argilominerais de alta atividade juntamente com elevada acidez do solo. As classes inseridas no SiBCS, na ordem dos Plintossolos, se mostraram adequadas para classificar os perfis e contemplam as varia����es relacionadas ao ambiente pedogen��tico.

Caracteriza����o e classificação de Neossolos da Ilha de Fernando de Noronha (PE)

Na ilha principal do Arquip��lago de Fernando de Noronha, condi����es peculiares de clima tropical, com franco dom��nio oce��nico, e material de origem de natureza vulc��nica contribuem para forma����o de solos pouco desenvolvidos, de especial interesse cient��fico, particularmente no que tange �� reestrutura����o do Sistema Brasileiro de Classificação de Solos (SiBCS). Com o objetivo de estud��-los, foram caracterizados morfol��gica, f��sica, qu��mica e mineralogicamente e classificados sete perfis de Neossolos de ocorr��ncia comum nesse ambiente insular, sendo dois Lit��licos, um "Saprol��tico", tr��s Regol��ticos e um Fl��vico. Os Neossolos Lit��licos apresentam contato l��tico constitu��do por fragmentos de rocha a menos de 50 cm de profundidade. O Neossolo "Saprol��tico" apresenta o contato l��tico superior aos 50 cm de profundidade, por��m precedido por rochas parcialmente decompostas (saprolito), que preservam ainda sua estrutura original. Os Neossolos Regol��ticos est��o relacionados aos dep��sitos sedimentares marinhos e s��o constitu��dos, predominantemente, por gr��os biocl��sticos carbon��ticos. O Neossolo Fl��vico, de origem col��vio-aluvial, apresenta camadas alternadas de materiais distintos, notoriamente, pela textura e mineralogia. Os Neossolos Lit��licos foram adequadamente classificados segundo a nova vers��o do SiBCS (Embrapa, 2006), que inclui o subgrupo "fragment��rio", sugerido durante o desenvolvimento deste trabalho. Os outros Neossolos n��o foram adequadamente enquadrados, ora por apresentarem caracter��sticas peculiares, ora pela aus��ncia de termos mais apropriados, que melhor explicitassem suas caracter��sticas distintas. Sugere-se a inclus��o no SiBCS da subordem dos Neossolos Saprol��ticos, do grande grupo dos Neossolos Regol��ticos Psam��ticos, e dos subgrupos dos Neossolos Regol��ticos Psam��ticos biocl��sticos carbon��ticos e Neossolos Fl��vicos Ta eutr��ficos biocl��sticos carbon��ticos.