Avaliação quantitativa da microbiota em solo de cultivo de soja transgênica em seis locais do Brasil.

A biomassa microbiana é responsável por funções chave para a qualidade do solo, e o cultivo de soja transgênica bem como o uso de herbicidas pode causar alterações sobre esse importante componente biológico do solo. O objetivo do presente trabalho foi avaliar quantitativamente o carbono (CBM) e o nitrogênio (NBM) da biomassa microbiana de solo cultivado com soja transgênica e aplicação de herbicidas em seis locais do Brasil na safra 2005/2006. O delineamento experimental foi de bloco ao acaso, com seis repetições, em sistema de plantio direto. Os tratamentos foram: T1: soja transgênica + glifosato; T2: soja transgênica + herbicidas convencionais; T3: soja parental convencional + herbicidas convencionais; T4: soja transgênica + capina manual; T5: soja parental convencional + capina manual, combinados com três cultivares em cada local estudado, totalizando 15 tratamentos. Os solos foram coletados no estágio R2 na profundidade 0-10 cm para a avaliação do CBM e do NBM. A análise de contrastes mostrou que o CBM não foi afetado pela transgenia, com exceção de Uberaba (MG). Não houve diferenças entre o manejo convencional da soja (soja e herbicidas convencionais) e o transgênico (soja transgênica com glifosato) em relação ao CBM, também com exceção de Uberaba. O NBM, em geral, não foi afetado pela transgenia. Em dois locais (Ponta Grossa/PR e Passo Fundo/RS), o manejo convencional apresentou maior NBM, enquanto o manejo transgênico com glifosato foi superior em Luiz Eduardo Magalhães (BA). Conclui-se que o cultivo transgênico da soja não afetou a biomassa microbiana do solo.Fertbio

Downregulation and forced expression of EWS-Fli1 fusion gene results in changes in the expression of G 1 regulatory genes

Chromosomal translocation t(11;22)(q24:q12) is detected in approximately 90% of tumours of the Ewing family (ET). This translocation results in EWS-Fli1 gene fusion which produces a EWS-Fli1 fusion protein acting as an aberrant transcriptional activator. We previously reported that the inhibition of EWS-Fli1 expression caused the G 0/G 1 arrest of ET cells. We, therefore, hypothesized that EWS-Fli1 may affect the expression of G 1 regulatory genes. Downregulation of EWS-Fli1 fusion proteins was observed 48 hours after the treatment with EWS-Fli1 antisense oligonucleotides. The expressions of G 1 cyclins, cyclin D1 and cyclin E, were markedly decreased in parallel with the reduction of EWS-Fli1 fusion protein. On the other hand, the expression of p21 and p27, which are important cyclin-dependent kinase inhibitors (CKIs) for G 1–S transition, was dramatically increased after the treatment with EWS-Fli1 antisense oligonucleotides. RT-PCR analysis showed that alteration of the expressions of the cyclins and CKIs occurred at the mRNA level. Furthermore, transfection of EWS-Fli1 cDNA to NIH3T3 caused transformation of the cells and induction of the expression of cyclin D1 and E. Clinical samples of ET also showed a high level of expression of cyclin D1 mRNA, whereas mRNAs for p21 and p27 were not detected in the samples. These findings strongly suggest that the G 1–S regulatory genes may be involved in downstream of EWS-Fli1 transcription factor, and that the unbalanced expression of G 1–S regulatory factors caused by EWS-Fli1 may lead to the tumorigenesis of ET. © 2001 Cancer Research Campaign http://www. bjcancer.co

Anotação Genômica de Bradyrhizobium japonicum estirpes CPAC 15 e CPAC 7: Resultados parciais e sua importância para a cultura de soja.

O solo é um importante complexo onde encontram-se nutrientes essenciais para as plantas. A maioria das plantas necessita de grandes quantidades de nitrogênio, todavia, este em geral se encontra de forma pouco assimilável no solo. Contudo, existem bactérias que são capazes de fixar o nitrogênio atmosférico (N2), disponibilizando-o para as plantas através de uma relação simbiõtica. Dentre estes, destaca-se a espécie Bradyrhizobium japonicum, com as estirpes CPAC 15 (=SEMIA 5079) e CPAC 7 (=SEMIA 5080), as quais são amplamente utilizadas como inoculantes para a cultura da soja (Glycine max (L.) Merr.) no Brasil. O presente trabalho teve como objetivo realizar a anotação manual do genoma de ambas as estirpes. Para isso, as sequências obtidas foram submetidas à anotação e à montagem utilizando o software ?System for Automated Bacterial Integrated Annotation? (SABIA), que integra vários programas de domínio público. Foram definidas as coding sequences (CDSs), que foram classificadas como hipotéticas, hipotéticas conservadas, válidas e não válidas. Os resultados mostraram elevada similaridade entre ambas as estirpes, com pequena diferença na quantidade de CDSs relacionadas ao transporte transmembrana e replicação em reparo, as quais estavam em maior quantidade na estirpe CPAC 15, provavelmente devido ao seu destaque como maior competitividade. Cerca de 50% do genoma apresentou CDSs classificadas como hipotéticas, sendo então necessários mais estudos para determinar a função desses genes.Fertbio

A modified vimentin histological score helps recognize pulmonary sarcomatoid carcinoma in small biopsy samples

Background: As pulmonary sarcomatoid carcinomas (PSCs) are life-threatening tumors, an improvement in their recognition in small-sized tumor samples is clinically warranted. Materials and Methods: Preoperative biopsy samples and paired surgical specimens from 20 pleomorphic carcinomas, two pulmonary blastomas and one carcinosarcoma (training set) were studied for vimentin immunohistochemistry. A modified vimentin histologic score (M-VHS) was devised by multiplying three independently assessed parameters, i.e. the percentage of positive cells (from 0 to 5+, by quintiles), the intensity of immunostaining (low=1 vs. strong=2) and the distribution pattern within the cytoplasm (partial=1 vs. diffuse=2), so ranging from 0 to 20. Forty-eight consecutive and independent cases of non-small cell lung carcinoma (NSCLC), including two additional cases of PSC, were used as control groups (validation set). Results: No differences in M-VHS were found between biopsies and surgical specimens of PSC, thus confirming the occurrence of stable epithelial mesenchymal transition (EMT) and hence the specific diagnosis of PSC. All types of PSC shared the same M-VHS. The M-VHS of 46 conventional NSCLC was by far lower (p<0.0001), whereas two additional cases of PSC showed the same results as the training set. Poorly differentiated NSCLC with marked pleomorphism but not stable EMT did not exhibit significantly increased M-VHS values. Conclusion: M-VHS helped in morphological analysis to render more definite diagnoses on small biopsies of PSC

Steady State of microemulsions in shear flow

Steady-state properties of microemulsions in shear flow are studied in the context of a Ginzburg-Landau free-energy approach. Explicit expressions are given for the structure factor and the time correlation function at the one loop level of approximation. Our results predict a four-peak pattern for the structure factor, implying the simultaneous presence of interfaces aligned with two different orientations. Due to the peculiar interface structure a non-monotonous relaxation of the time correlator is also found.Comment: 5 pages, 3 figure

Regulatory nodD1 and nodD2 genes of Rhizobium tropici strain CIAT 899 and their roles in the early stages of molecular signaling and host-legume nodulation.

Nodulation and symbiotic nitrogen fixation are mediated by several genes, both of the host legume and of the bacterium. The rhizobial regulatory nodD gene plays a critical role, orchestrating the transcription of the other nodulation genes. Rhizobium tropici strain CIAT 899 is an effective symbiont of several legumes?with an emphasis on common bean (Phaseolus vulgaris)?and is unusual in carrying multiple copies of nodD, the roles of which remain to be elucidated. Results: Phenotypes, Nod factors and gene expression of nodD1 and nodD2 mutants of CIAT 899 were compared with those of the wild type strain, both in the presence and in the absence of the nod-gene-inducing molecules apigenin and salt (NaCl). Differences between the wild type and mutants were observed in swimming motility and IAA (indole acetic acid) synthesis. In the presence of both apigenin and salt, large numbers of Nod factors were detected in CIAT 899, with fewer detected in the mutants. nodC expression was lower in both mutants; differences in nodD1 and nodD2 expression were observed between the wild type and the mutants, with variation according to the inducing molecule, and with a major role of apigenin with nodD1 and of salt with nodD2. In the nodD1 mutant, nodulation was markedly reduced in common bean and abolished in leucaena (Leucaena leucocephala) and siratro (Macroptilium atropurpureum), whereas a mutation in nodD2 reduced nodulation in common bean, but not in the other two legumes. Conclusion: Our proposed model considers that full nodulation of common bean by R. tropici requires both nodD1 and nodD2, whereas, in other legume species that might represent the original host, nodD1 plays the major role. In general, nodD2 is an activator of nod-gene transcription, but, in specific conditions, it can slightly repress nodD1. nodD1 and nodD2 play other roles beyond nodulation, such as swimming motility and IAA synthesis

Mechanisms for slow strengthening in granular materials

Several mechanisms cause a granular material to strengthen over time at low applied stress. The strength is determined from the maximum frictional force F_max experienced by a shearing plate in contact with wet or dry granular material after the layer has been at rest for a waiting time \tau. The layer strength increases roughly logarithmically with \tau -only- if a shear stress is applied during the waiting time. The mechanisms of strengthening are investigated by sensitive displacement measurements and by imaging of particle motion in the shear zone. Granular matter can strengthen due to a slow shift in the particle arrangement under shear stress. Humidity also leads to strengthening, but is found not to be its sole cause. In addition to these time dependent effects, the static friction coefficient can also be increased by compaction of the granular material under some circumstances, and by cycling of the applied shear stress.Comment: 21 pages, 11 figures, submitted to Phys. Rev.