The aim of this work was to characterize rhizobia isolated from the root nodules of cowpea (Vigna unguiculata) plants cultivated in Amazon soils samples by means of ARDRA (Amplified rDNA Restriction Analysis) and sequencing analysis, to know their phylogenetic relationships. The 16S rRNA gene of rhizobia was amplified by PCR (polymerase chain reaction) using universal primers Y1 and Y3. The amplification products were analyzed by the restriction enzymes HinfI, MspI and DdeI and also sequenced with Y1, Y3 and six intermediate primers. The clustering analysis based on ARDRA profiles separated the Amazon isolates in three subgroups, which formed a group apart from the reference isolates of Bradyrhizobium japonicum and Bradyrhizobium elkanii. The clustering analysis of 16S rRNA gene sequences showed that the fast-growing isolates had similarity with Enterobacter, Rhizobium, Klebsiella and Bradyrhizobium and all the slow-growing clustered close to Bradyrhizobium.

Root nodule bacteria were trapped within cowpea (Vigna unguiculata) in soils with different cultivation histories collected from the Amazonian rainforest in northern Brazil. Analysis of the 16S rRNA gene sequences of six strains (BR 3351 T , BR 3307, BR 3310, BR 3315, BR 3323 BR and BR 3361) isolated from cowpea nodules showed that they formed a distinct group within the genus Bradyrhizobium, which was separate from previously identified type strains. Phylogenetic analyses of three housekeeping genes (glnII, recA and rpoB) revealed that Bradyrhizobium huanghuaihaiense CCBAU 23303 T was the most closely related type strain (96 % sequence similarity or lower). Chemotaxonomic data, including fatty acid profiles (predominant fatty acids being C 16 : 0 and summed feature 8), the slow growth rate and carbon compound utilization patterns supported the assignment of the strains to the genus Bradyrhizobium. The results of DNA-DNA hybridizations, antibiotic resistance and physiological tests differentiated these novel strains from the most closely related species of the genus Bradyrhizobium with validly published names. Symbiosis-related genes for nodulation (nodC) and nitrogen fixation (nifH) grouped the novel strains of the genus Bradyrhizobium together with Bradyrhizobium iriomotense strain EK05 T , with 94 % and 96 % sequence similarity, respectively. Based on these data, these six strains represent a novel species for which the name Brabyrhizobium manausense sp. nov. (BR 3351 T 5HAMBI 3596 T ), is proposed.The family Leguminosae is one of the most abundant plant families in the Amazonian rainforest (AR) with more than 1240 species and 140 genera of all three subfamilies (Caesalpinioideae, Mimosoideae and Papilionoideae) catalogued (Ducke, 1949;Silva et al., 1988). This family is ecologically and economically important to the biome, because it contains pioneer species that revegetate bare soils, species that produce grain for food and species used for timber production. Many legume species are capable of forming root (or sometimes stem) nodules, which contain nitrogen-fixing bacterial symbionts, collectively known as 'rhizobia ' (Sprent, 1995). The capacity to nodulate appears to be the rule for leguminous plants within the AR, since more than 80 % of species of the subfamilies Papilionoideae and Mimosoideae do it; however, only about 20 % of the Caesalpinioideae are capable of forming nodules (de Faria, et al., 1989(de Faria, et al., , 2010Moreira, et al., 1993). Legumes contribute significantly to the AR N-balance, with more than 1006 10 8 kg of nitrogen being fixed annually (Salati et al., 1982;Martinelli et al., 1992;Gehring, et al., 2005).Bacteria of the genus Bradyrhizobium have been reported to comprise the majority of root nodule bacteria isolated from The GenBank/EMBL/DDBJ accession number for the 16S rRNA, glnII, recA, rpoB, dnaK, gyrB, nodC and nifH gene sequences of BR3351 T are HQ641226, KF785986, KF785992, KF785998, KF786000, KF786001, KF786002 and KF786003, respectively. Abbreviation: AR, Amazonian ra...

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RESUMO: O DNA recombinante, assunto abstrato do currículo de Biologia, se não for devidamente abordado pelos professores, poderá ocasionar entendimento distorcido sobre suas implicações técnicas, sociais e éticas. Este trabalho teve como objetivo investigar o tema DNA recombinante nas ementas do Curso de Licenciatura em Ciências Biológicas de uma universidade pública localizada no estado do Rio de Janeiro, e conhecer a metodologia empregada para o ensino do tema. Na pesquisa, optou-se pela análise das ementas que compõem o curso na instituição e a utilização de entrevistas com dez licenciandos do quarto ano e com um docente que ministra a disciplina Genética Molecular. Os resultados revelaram que das cinco ementas que mencionam assuntos relacionados ao DNA recombinante, uma disciplina tinha sido lecionada nos últimos cinco anos. Os principais recursos didáticos apontados pelos participantes da pesquisa foram livro, filme e site na internet. A maioria das aulas sobre o assunto foi expositiva com o uso de slides, ilustrações, artigos, textos, vídeos e práticas demonstrativas.

O estudo sobre as células é essencial para os estudantes se apropriarem dos conhecimentos sobre a composição dos organismos, da sua fisiologia e das relações ecológicas estabelecidas. Nesse contexto, o presente trabalho teve como objetivo investigar as vivências de ensino-aprendizagem de licenciandos em Ciências Biológicas durante seus estágios supervisionados nas escolas, com enfoque no ensino sobre as células.  Desse modo, foi realizada uma pesquisa quali-quantitativa por meio de um questionário respondido pelos participantes. Os resultados apontaram que as vivências dos licenciandos com o ensino sobre células, quando ocorreu nas escolas, foram sobretudo baseadas em aulas expositivas, e isso vai contra o recomendado para uma aprendizagem significativa, contextualizada e que prioriza o protagonismo dos alunos através de metodologias diferenciadas.