Temporal dynamics of microbiota before and after host death

The habitats that animals, humans and plants provide for microbial communities are inevitably transient, changing drastically when these hosts die. Because microbes associated with living hosts are ensured prime access to the deceased host's organic matter, it is feasible that opportunistic, adaptable lifestyles are widespread among host-associated microbes. Here we investigate the temporal dynamics of microbiota by starving to death a host-the planktonic Crustacean Daphnia magna-and tracking the changes in its microbial community as it approaches death, dies and decomposes. Along with obligate host-associated microbes that vanished after the host's death and decomposers that appeared after the host's death, we also detected microbes with opportunistic lifestyles, seemingly capable of exploiting the host even before its death. We suggest that the period around host death plays an important role for host-microbiota ecology and for the evolution of hosts and their microbes

Prevalência e fatores associados ao tabagismo em estudantes de medicina de uma universidade em Passo Fundo (RS) Prevalence of and variables related to smoking among medical students at a university in the city of Passo Fundo, Brazil

OBJETIVO: Verificar a prevalência e fatores associados ao tabagismo entre os acadêmicos de medicina e avaliar o perfil desse grupo. MÉTODOS: Responderam a um questionário autoaplicável, contendo perguntas sobre consumo e atitudes relacionadas ao tabagismo, 316 acadêmicos de medicina (98,7% do total) da Universidade de Passo Fundo. Segundo recomendações da Organização Mundial da Saúde, os estudantes foram classificados em fumantes diários, fumantes ocasionais, ex-fumantes ou não-fumantes, sendo considerados fumantes ativos os nas duas primeiras categorias. RESULTADOS: Observou-se que 16,5% dos acadêmicos eram fumantes ativos (5,4% diários e 11,1% ocasionais) e 3,5% eram ex-fumantes. A média de idade foi 22,2 ± 2,4 anos. Os fatores significativamente associados ao tabagismo (p < 0,05) foram sexo masculino, pai fumante, uso regular de bebidas alcoólicas e uso de antidepressivos ou ansiolíticos. Verificou-se que 69,2% dos fumantes iniciaram o tabagismo entre 15 e 19 anos, tendo como principais motivações a vontade própria e/ou a influência de amigos. A conceituação do tabagismo como doença foi significativamente maior entre os não-fumantes. Quanto à carga tabágica, 70,6% dos fumantes consumiam 1-10 cigarros por dia. Entre os fumantes, 67,3% já tentaram parar de fumar, 96,0% acreditam serem capazes de fazê-lo e 87,2% pretendem deixar de fumar, ao passo que 92,3% admitiram que o cigarro faz mal à saúde. CONCLUSÕES: A prevalência do tabagismo ainda é significativa entre os acadêmicos de medicina, sendo fundamental estabelecer estratégias preventivas e de cessação mais efetivas a fim de se tentar reduzir o número de fumantes entre os futuros médicos.<br>OBJECTIVE:To determine the prevalence of and factors associated with smoking among medical students, as well as to evaluate the profile of this group. METHODS: A total of 316 medical students (98.7% of the total) at the University of Passo Fundo, in the city of Passo Fundo, Brazil, completed a self-report questionnaire with questions on tobacco intake and on attitudes related to smoking. In accordance with the World Health Organization guidelines, the students were classified as daily smokers, occasional smokers, former smokers or nonsmokers, those in the two first categories being considered active smokers. RESULTS: We found that 16.5% of the students were active smokers (daily smokers, 5.4%; occasional smokers, 11.1%) and that 3.5% were former smokers. The mean age was 22.2 ± 2.4 years. Factors significantly associated with the smoking habit (p < 0.05) were male gender, paternal smoking, regular alcohol consumption and use of antidepressants or anxiolytics. For the majority (69.2%) of the smokers, the age at smoking onset was 15-19 years of age, and the main motivations to start smoking were selfinitiative and influence of friends. The conceptualization of smoking as an illness was significantly higher among the nonsmokers. In 70.6% of the smokers, tobacco intake was 1-10 cigarettes a day. Among the smokers, 92.3% agreed that smoking is harmful to health, 67.3% had tried to quit smoking, 96.0% believed themselves able to do so, and 87.2% intended to quit smoking. CONCLUSIONS: The prevalence of smoking remains significant among medical students. Therefore, it is fundamental that we develop more effective strategies for smoking prevention and cessation in order to reduce the number of smokers among future doctors

Patterns of bacterial diversity in the marine planktonic particulate matter continuum

12 pages, 8 figures, supplemental material http://www.nature.com/ismej/journal/v11/n4/suppinfo/ismej2016166s1.htmlDepending on their relationship with the pelagic particulate matter, planktonic prokaryotes have traditionally been classified into two types of communities: free-living (FL) or attached (ATT) to particles, and are generally separated using only one pore-size filter in a differential filtration. Nonetheless, particulate matter in the oceans appears in a continuum of sizes. Here we separated this continuum into six discrete size-fractions, from 0.2 to 200 μm, and described the prokaryotes associated to each of them. Each size-fraction presented different bacterial communities, with a range of 23–42% of unique (OTUs) in each size-fraction, supporting the idea that they contained distinct types of particles. An increase in richness was observed from the smallest to the largest size-fractions, suggesting that increasingly larger particles contributed new niches. Our results show that a multiple size-fractionation provides a more exhaustive description of the bacterial diversity and community structure than the use of only one filter. In addition, and based on our results, we propose an alternative to the dichotomy of FL or ATT lifestyles, in which we differentiate the taxonomic groups with preference for the smaller fractions, those that do not show preferences for small or large fractions, and those that preferentially appear in larger fractionsThis research was funded by projects STORM (CTM2009-09352), ADEPT (CTM2011-23458), DOREMI (CTM2012-34294), REMEI (CTM2015-70340-R) and ANIMA (CTM2015-65720-R) funded by the former Ministry of Science and Innovation and the Ministry of Economy and Competitiveness. MM was supported by a CSIC JAE-Predoc Grant and by the Ministry of Labor, Employment and Social Security. EB was supported by an FPI predoctoral fellowship from the Spanish Ministery of Economy and CompetitivenessPeer Reviewe

Posttranscriptional Regulation of Angiogenesis Through AU-Rich mRNA Degradation: Potential Application in Cancer Therapy

International audienc

Fungal Pre-mRNA 3′-End Processing

3' end processing of messenger RNAs (mRNAs) is not only an essential step in eukaryotic gene expression, but it also impacts many other aspects of mRNA maturation and decay. A large portion of eukaryotic genes produce multiple mRNAs with different 3' ends through alternative cleavage/polyadenylation (APA). mRNA 3' processing and especially APA has been increasingly recognized as an important mechanism for gene regulation. Much of what we currently know about eukaryotic mRNA 3' processing came from studies using the genetically tractable yeast systems. Here we review the fungal mRNA 3' processing system by describing both the evolutionarily conserved mechanisms as well as the fungus-specific features