Beer is one of the oldest alcoholic beverages and is produced by the fermentation of sugars derived from starches present in cereal grains. Contrary to lager beers, made by bottom-fermenting strains of Saccharomyces pastorianus, a hybrid yeast, ale beers are closer to the ancient beer type and are fermented by S. cerevisiae, a top-fermenting yeast. Here, we use population genomics to investigate (1) the closest relatives of top-fermenting beer yeasts; (2) whether top-fermenting yeasts represent an independent domestication event separate from those already described; (3) whether single or multiple beer yeast domestication events can be inferred; and (4) whether top-fermenting yeasts represent non-recombinant or recombinant lineages. Our results revealed that top-fermenting beer yeasts are polyphyletic, with a main clade composed of at least three subgroups, dominantly represented by the German, British, and wheat beer strains. Other beer strains were phylogenetically close to sake, wine, or bread yeasts. We detected genetic signatures of beer yeast domestication by investigating genes previously linked to brewing and using genome-wide scans. We propose that the emergence of the main clade of beer yeasts is related with a domestication event distinct from the previously known cases of wine and sake yeast domestication. The nucleotide diversity of the main beer clade more than doubled that of wine yeasts, which might be a consequence of fundamental differences in the modes of beer and wine yeast domestication. The higher diversity of beer strains could be due to the more intense and different selection regimes associated to brewing.

The study of microbe domestication has witnessed major advances that contribute to a better understanding of the emergence of artificially selected phenotypes and set the foundations of their rational improvement for biotechnology. Several features make Saccharomyces cerevisiae an ideal model for such a study, notably the availability of a catalogue of signatures of artificial selection and the extensive knowledge available on its biological processes. Here, we investigate with population and comparative genomics a set of strains used for cachaça fermentation, a Brazilian beverage based on the fermentation of sugar cane juice. We ask if the selective pressures posed by this fermentation have given rise to a domesticated lineage distinct from the ones already known, like wine, beer, bread, and sake yeasts. Our results show that cachaça yeasts derive from wine yeasts that have undergone an additional round of domestication, which we define as secondary domestication. As a consequence, cachaça strains combine features of wine yeasts, such as the presence of genes relevant for wine fermentation and advantageous gene inactivations, with features of beer yeasts like resistance to the effects of inhibitory compounds present in molasses. For other markers like those related to sulfite resistance and biotin metabolism our analyses revealed distributions more complex than previously reported that support the secondary domestication hypothesis. We propose a multilayered microbe domestication model encompassing not only transitions from wild to primarily domesticated populations, as in the case of wine yeasts, but also secondary domestications like those of cachaça yeasts.

Saccharomyces cerevisiae—the most emblematic and industrially relevant yeast—has a long list of taxonomical synonyms. Formerly considered as distinct species, some of the synonyms represent variants with important industrial implications, like Saccharomyces boulardii or Saccharomyces diastaticus, but with an unclear status, especially among the fermentation industry, the biotechnology community and biologists not informed on taxonomic matters. Here, we use genomics to investigate a group of 45 reference strains (type strains) of former Saccharomyces species that are currently regarded as conspecific with S. cerevisiae. We show that these variants are distributed across the phylogenetic spectrum of domesticated lineages of S. cerevisiae, with emphasis on the most relevant technological groups, but absent in wild lineages. We analyzed the phylogeny of a representative and well-balanced dataset of S. cerevisiae genomes that deepened our current ecological and biogeographic assessment of wild populations and allowed the distinction, among wild populations, of those associated with low- or high-sugar natural environments. Some wild lineages from China were merged with wild lineages from other regions in Asia and in the New World, thus giving more resolution to the current model of expansion from Asia to the rest of the world. We reassessed several key domestication markers among the different domesticated populations. In some cases, we could trace their origin to wild reservoirs, while in other cases gene inactivation associated with domestication was also found in wild populations, thus suggesting that natural adaptation to sugar-rich environments predated domestication.

Conocimientos y prácticas de los adolescentes sobre EST y SIDA en adolescentes en dos escuelas públicas municipales de Río de Janeiro Abstract ResumenEl presente estudio tiene como objetivo analizar los conocimientos que tienen los jóvenes sobre la prevención de EST y del SIDA y la adopción de los preservativos masculinos. Se realizó un estudio cuantitativo con 492 adolescentes de dos escuelas del municipio de Río de Janeiro. Los datos fueron obtenidos en el año de 2003 a través de cuestionarios y analizados con el software EPI-INFO 6.0. Respecto a la prevención, 94,5% considera que el preservativo es el método más eficaz, sin embargo, 10,8% considera que las píldoras anticonceptivas también previenen las EST y el SIDA y 16,9% de los adolescentes entrevistados revela que mantener relaciones sexuales sólo con sus parejas es un método de prevención eficaz . Con relación a las prácticas de prevención, se analizaron solamente los adolescentes con vida sexual activa (492), 11% nunca uso preservativos durante las relaciones sexuales, 32,7% los utiliza algunas veces, y 53,3% los utiliza en todas las relaciones sexuales. De este modo, se concluyó que el conocimiento no se expresa directamente en las práticas de prevención y que la relación estable y el uso de anticonceptivos están asociados a la prevención de EST y SIDA, de forma positiva o negativa..

Soil yeasts represent a poorly known fraction of the soil microbiome due to limited ecological surveys. Here, we provide the first comprehensive inventory of cultivable soil yeasts in a Mediterranean ecosystem, which is the leading biodiversity hotspot for vascular plants and vertebrates in Europe. We isolated and identified soil yeasts from forested sites of Serra da Arrábida Natural Park (Portugal), representing the Mediterranean forests, woodlands and scrub biome. Both cultivation experiments and the subsequent species richness estimations suggest the highest species richness values reported to date, resulting in a total of 57 and 80 yeast taxa, respectively. These values far exceed those reported for other forest soils in Europe. Furthermore, we assessed the response of yeast diversity to microclimatic environmental factors in biotopes composed of the same plant species but showing a gradual change from humid broadleaf forests to dry maquis. We observed that forest properties constrained by precipitation level had strong impact on yeast diversity and on community structure and lower precipitation resulted in an increased number of rare species and decreased evenness values. In conclusion, the structure of soil yeast communities mirrors the environmental factors that affect aboveground phytocenoses, aboveground biomass and plant projective cover.

A universalidade no SUS: pensamento dos usuários A universalidade no SUS: pensamento dos usuários A universalidade no SUS: pensamento dos usuários A universalidade no SUS: pensamento dos usuários A universalidade no SUS: pensamento dos usuários Pontes APM, Cesso RGD, Oliveira DC, Gomes AMT O PRINCÍPIO DE UNIVERSALIDADE DO ACESSO AOS SERVIÇOS DE SAÚDE: O QUE PENSAM OS USUÁRIOS?Esc Anna Nery Rev Enferm 2009 jul-set; 13 (3): 500-07 RESUMOEsta pesquisa objetivou analisar a percepção dos usuários sobre o acesso universal aos serviços de saúde no SUS, com vistas a discutir o princípio de universalidade. Estudo qualitativo, desenvolvido em um hospital localizado no Rio de Janeiro, com 24 usuários. Os dados foram coletados por meio de entrevistas e analisados a partir da técnica de análise de conteúdo. Foram identificadas 1.178 unidades de registro agrupadas em 76 temas, que deram origem a seis categorias: Determinação das dificuldades para o alcance do atendimento no SUS; o atendimento no SUS: efetivação e facilidades; medicações e exames no contexto do SUS; fragilidades no processo de atendimento na concretização do princípio de universalidade; universalização da assistência; e a presença do INAMPS no ideário dos usuários. Como demonstraram os resultados, os usuários têm uma atitude positiva diante do sistema, apesar das diversas dificuldades encontradas, e, ainda, suas práticas são influenciadas pela percepção que têm do acesso. This study aimed to analyze the perception of users about universal access to health services in the SUS, with a view to discussing the principle of universality. Qualitative study, developed in a hospital located in Rio de Janeiro, with 24 users. Data were collected through interviews, and were analyzed by the technical of content analysis. 1178 units of records have been identified and grouped in 76 subjects, which resulted in 06 categories: Determination of the difficulties to the extent of care in the SUS; the attendance in the SUS: effective and facilities; Medications and examinations in the context of the SUS; Weaknesses in the process of care in implementation of the principle of universality; Universalization of the assistance; and the presence of INAMPS in the ideas of the user. As shown by the results, users have a positive attitude ahead of the system, despite the many difficulties encountered, and yet, their practices are influenced by the perception that they have about the access. Este estudio tuvo como objetivo analizar la percepción de los usuarios sobre el acceso universal a los servicios de salud en el SUS, con miras a discutir el principio de universalidad. Estudio cualitativo, desarrollado en un hospital ubicado en Río de Janeiro-Brasil, con 24 usuarios. Los datos fueron colectados por medio de la técnica de entrevista y analizados a partir de los análisis de contenido. Fueron identificados 1178 unidades de registro agrupadas en 76 temas que dieron origien a 06 categorías: Determinación de las dificultades en alcanzar atención en el SUS; la atención en el Sistema Único de...

The adaptation of the yeast Saccharomyces cerevisiae to man-made environments for the fermentation of foodstuffs and beverages illustrates the scientific, social, and economic relevance of microbe domestication. Here we address a yet unexplored aspect of S. cerevisiae domestication, that of the emergence of lineages harboring some domestication signatures but that do not fit completely in the archetype of a domesticated yeast, by studying S. cerevisiae strains associated with processed olives, namely table olives, olive brine, olive oil, and alpechin. We confirmed earlier observations that reported that the Olives population results from a hybridization between S. cerevisiae and S. paradoxus. We concluded that the olive hybrids form a monophyletic lineage and that the S. cerevisiae progenitor belonged to the wine population of this species. We propose that homoploid hybridization gave rise to a diploid hybrid genome, which subsequently underwent the loss of most of the S. paradoxus sub-genome. Such a massive loss of heterozygosity was probably driven by adaptation to the new niche. We observed that olive strains are more fit to grow and survive in olive brine than control S. cerevisiae wine strains and that they appear to be adapted to cope with the presence of NaCl in olive brine through expansion of copy number of ENA genes. We also investigated whether the S. paradoxus HXT alleles retained by the Olives population were likely to contribute to the observed superior ability of these strains to consume sugars in brine. Our experiments indicate that sugar consumption profiles in the presence of NaCl are different between members of the Olives and Wine populations and only when cells are cultivated in nutritional conditions that support adaptation of their proteome to the high salt environment, which suggests that the observed differences are due to a better overall fitness of olives strains in the presence of high NaCl concentrations. Although relic olive hybrids exhibit several characteristics of a domesticated lineage, tangible benefits to humans cannot be associated with their phenotypes. These strains can be seen as a case of adaptation without positive or negative consequences to humans, that we define as a quasi-domestication.

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