Resumo A meiose é considerada um tópico persistentemente difícil para estudantes de diferentes níveis de ensino, sendo objeto de muitos relatos de entendimentos incorretos e concepções alternativas. Este é o primeiro trabalho a utilizar um Inventário de Conceitos de Meiose com estudantes de Biologia brasileiros para analisar a compreensão de conceitos genéticos elementares associados à meiose entre calouros e licenciandos veteranos. O desempenho geral no inventário foi semelhante para ambos os grupos, variando de baixo a médio. Observou-se que os estudantes compartilham concepções alternativas, especialmente sobre a disposição dos alelos gênicos nos cromossomos, estrutura dos cromossomos, ploidia celular, replicação do DNA e produtos da meiose. Entrevistas cognitivas com estudantes selecionados possibilitaram analisar como estes construíram suas respostas e explicações. Os resultados apontam para a necessidade de se enfatizar os conceitos discutidos neste trabalho no ensino de genética e citologia, bem como desenvolver novas estratégias de ensino. alternativas veteranos grupos médio Observouse Observou cromossomos celular explicações citologia

Abstract Meiosis is regarded as a consistently challenging topic for students across various educational levels, constituting a domain within the field of genetics that has been extensively documented to elicit misunderstandings and alternative conceptions. The present study deals with elementary genetic concepts associated with meiosis among undergraduates in their first year (freshmen) and in their senior year (pre-service teachers). Overall performance on the inventory was similar for both groups, ranging from low to medium. The research revealed that students present alternative conceptions, particularly pertaining to the organization of gene alleles on chromosomes, the structure of chromosomes, cellular ploidy, DNA replication, and the products of meiosis. By conducting cognitive interviews with a chosen cohort of students, it was possible to analyze the way they formulated their responses and explanations. The results point to the need to emphasize the concepts discussed in this work in the teaching of genetics and cytology while concurrently devising novel instructional methodologies. levels conceptions freshmen (freshmen preservice pre service teachers. teachers . teachers) groups medium chromosomes ploidy replication explanations methodologies

Abstract As in many countries, in Brazil science is conducted mostly inside universities by professors and their graduate students and post-docs. This article aims at assessing the circumstances under which university professors of a biological sciences institute of a public university are willing to adopt the term ‘scientist’ as a form of self-designation. Using an online questionnaire (n=21) and two focus groups (n=12) we investigated how these professionals call or describe themselves under different situations and for distinct publics. We found that most professors prefer not to call themselves a ‘scientist’. They find it a natural choice not to use the term ‘scientist’ to designate their job in scientific research and believe that university professor is appropriate as well as it is a respectful title. However, the participants could envision possible impacts of this attitude on the general public and implications for the public perception of science and technology such as investment and science career choice. The origin of the word scientist and the history of the Brazilian scientific community are brought about to shed some light on the gathered data.

Phytases are a group of enzymes that catalyze phytic acid hydrolysis with release of phosphorus (P). The ability of Chromobacterium sp. to produce phytase was detected in 115 out of 118 candidate bacteria isolated from different Brazilian biomas. This is the first report revealing the genus Chromobacterium as phytase producer.

Mating-type genes control the entry into the sexual cycle, mating identity and sexual development in fungi. The mat A-2 and mat A-3 genes, present in the mat A idiomorph of the filamentous fungus Neurospora crassa, are required for post-fertilization functions but are not essential for mating identity. Their putative roles as transcription factors are based on the similarity of mat A-2 with the Podospora anserina SMR1 gene and an HMG motif present in the mat A-3 gene. In this work the yeast two-hybrid system was used to identify transcriptional activity and protein-protein interaction of N. crassa mat A-2 and mat A-3 genes. We observed that the mat A-3 protein alone is capable of weakly activating transcription of yeast reporter genes; it also binds with low specificity to the GAL1 promoter sequence, possibly due to its HMG domain. Our results also indicate that mat A-3 is capable to form homodimers, and interact with mat A-2. Interference on yeast growth was observed on some transformants suggesting a toxic action of the mat A-2 protein. Our data on pattern of interactions of mat proteins contributes towards understanding the control of vegetative and sexual cycles in filamentous fungi.