Evaluation of cytochrome P-450 concentration in Saccharomyces cerevisiae strains

Saccharomyces cerevisiae has been widely used in mutagenicity tests due to the presence of a cytochrome P-450 system, capable of metabolizing promutagens to active mutagens. There are a large number of S. cerevisiae strains with varying abilities to produce cytochrome P-450. However, strain selection and ideal cultivation conditions are not well defined. We compared cytochrome P-450 levels in four different S. cerevisiae strains and evaluated the cultivation conditions necessary to obtain the highest levels. The amount of cytochrome P-450 produced by each strain varied, as did the incubation time needed to reach the maximum level. The highest cytochrome P-450 concentrations were found in media containing fermentable sugars. The NCYC 240 strain produced the highest level of cytochrome P-450 when grown in the presence of 20 % (w/v) glucose. The addition of ethanol to the media also increased cytochrome P-450 synthesis in this strain. These results indicate cultivation conditions must be specific and well-established for the strain selected in order to assure high cytochrome P-450 levels and reliable mutagenicity results.Linhagens de Saccharomyces cerevisiae tem sido amplamente empregadas em testes de mutagenicidade devido à presença de um sistema citocromo P-450 capaz de metabolizar substâncias pró-mutagênicas à sua forma ativa. Devido à grande variedade de linhagens de S. cerevisiae com diferentes capacidades de produção de citocromo P-450, torna-se necessária a seleção de cepas, bem como a definição das condições ideais de cultivo. Neste trabalho, foram comparados os níveis de citocromo P-450 em quatro diferentes linhagens de S. cerevisiae e avaliadas as condições de cultivo necessárias para obtenção de altas concentrações deste sistema enzimático. O maior nível enzimático foi encontrado na linhagem NCYC 240 em presença de 20 % de glicose (p/v). A adição de etanol ao meio de cultura também produziu um aumento na síntese de citocromo P-450. Estes resultados indicam que as condições de cultivo devem ser específicas e bem definidas para a linhagem selecionada, garantindo assim elevados níveis de citocromo P-450 e, conseqüentemente, a confiabilidade nos testes de mutagenicidade.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Evaluation of cytochrome P-450 concentration in Saccharomyces cerevisiae strains

Saccharomyces cerevisiae has been widely used in mutagenicity tests due to the presence of a cytochrome P-450 system, capable of metabolizing promutagens to active mutagens. There are a large number of S. cerevisiae strains with varying abilities to produce cytochrome P-450. However, strain selection and ideal cultivation conditions are not well defined. We compared cytochrome P-450 levels in four different S. cerevisiae strains and evaluated the cultivation conditions necessary to obtain the highest levels. The amount of cytochrome P-450 produced by each strain varied, as did the incubation time needed to reach the maximum level. The highest cytochrome P-450 concentrations were found in media containing fermentable sugars. The NCYC 240 strain produced the highest level of cytochrome P-450 when grown in the presence of 20 % (w/v) glucose. The addition of ethanol to the media also increased cytochrome P-450 synthesis in this strain. These results indicate cultivation conditions must be specific and well-established for the strain selected in order to assure high cytochrome P-450 levels and reliable mutagenicity results.Linhagens de Saccharomyces cerevisiae tem sido amplamente empregadas em testes de mutagenicidade devido à presença de um sistema citocromo P-450 capaz de metabolizar substâncias pró-mutagênicas à sua forma ativa. Devido à grande variedade de linhagens de S. cerevisiae com diferentes capacidades de produção de citocromo P-450, torna-se necessária a seleção de cepas, bem como a definição das condições ideais de cultivo. Neste trabalho, foram comparados os níveis de citocromo P-450 em quatro diferentes linhagens de S. cerevisiae e avaliadas as condições de cultivo necessárias para obtenção de altas concentrações deste sistema enzimático. O maior nível enzimático foi encontrado na linhagem NCYC 240 em presença de 20 % de glicose (p/v). A adição de etanol ao meio de cultura também produziu um aumento na síntese de citocromo P-450. Estes resultados indicam que as condições de cultivo devem ser específicas e bem definidas para a linhagem selecionada, garantindo assim elevados níveis de citocromo P-450 e, conseqüentemente, a confiabilidade nos testes de mutagenicidade

Sobrexploração de Philodendron spiritus-sancti G.S.Bunting e a necessidade de implantação de uma política para a conservação de imbés

We present an opinion article contextualizing the current situation of Philodendron spiritus-sancti, an emblematic and endangered species of Araceae, endemic to the Brazilian state of Espírito Santo and highly targeted in the ornamental plant trade. We discuss how the distance between researchers and the civil society difficults the aquisition of information about the species and, consequently, its conservation. Furthermore, we briefly present some considerations to implement a conservation policy for the group.Presentamos un artículo de opinión que contextualiza la situación actual de Philodendron spiritus-sancti, una especie emblemática y amenazada de Araceae, endémica del estado de Espírito Santo y muy buscada en el comercio de plantas ornamentales. Discutimos cómo la distancia entre los investigadores y la sociedad civil dificulta la adquisición de información sobre la especie y, en consecuencia, su conservación. Además, presentamos brevemente algunas consideraciones para la implementación de una política de conservación del grupo.Apresentamos um artigo de opinião contextualizando a atual situação de Philodendron spiritus-sancti, uma espécie de Araceae emblemática e ameaçada de extinção, endêmica do estado do Espírito Santo e altamente visada no comércio de plantas ornamentais. Discutimos como o distanciamento entre pesquisadores e a sociedade civil dificulta a aquisição de informações sobre a espécie e, consequentemente, sua conservação. Além disso, apresentamos brevemente algumas considerações voltadas à implementação de uma política de conservação para o grupo

Supplemental Information 1: Supplementary tables and figures

Philodendron is the second most diverse genus of the Araceae, a tropical monocot family with significant morphological diversity along its wide geographic distribution in the Neotropics. Although evolutionary studies of Philodendron were conducted in recent years, the phylogenetic relationship among its species remains unclear. Additionally, analyses conducted to date suggested the inclusion of all American representatives of a closely-related genus, Homalomena, within the Philodendron clade. A thorough evaluation of the phylogeny and timescale of these lineages is thus necessary to elucidate the tempo and mode of evolution of this large Neotropical genus and to unveil the biogeographic history of Philodendron evolution along the Amazonian and Atlantic rainforests as well as open dry forests of South America. To this end, we have estimated the molecular phylogeny for 68 Philodendron species, which consists of the largest sampling assembled to date aiming the study of the evolutionary affinities. We have also performed ancestral reconstruction of species distribution along biomes. Finally, we contrasted these results with the inferred timescale of Philodendron and Homalomena lineage diversification. Our estimates indicate that American Homalomena is the sister clade to Philodendron. The early diversification of Philodendron took place in the Amazon forest from Early to Middle Miocene, followed by colonization of the Atlantic forest and the savanna-like landscapes, respectively. Based on the age of the last common ancestor of Philodendron, the species of this genus diversified by rapid radiations, leading to its wide extant distribution in the Neotropical region

Recognition of the genus Thaumatophyllum Schott − formerly Philodendron subg. Meconostigma (Araceae) − based on molecular and morphological evidence

Philodendron subgenus Meconostigma has been a well-circumscribed group since 1829. Members of this group are easily distinguished by diagnostic morphological characters as well as by a distinct ecology and geographical distribution. Based on molecular, morphological and cytological evidence, we propose the recognition of P. subg. Meconostigma as a distinct genus, Thaumatophyllum Schott. We also present the necessary new combinations, an emended key and some nomenclatural and taxonomic corrections regarding 21 names of Thaumatophyllum

Large emissions from floodplain trees close the Amazon methane budget

Wetlands are the largest global source of atmospheric methane (CH4), a potent greenhouse gas. However, methane emission inventories from the Amazon floodplain, the largest natural geographic source of CH4 in the tropics, consistently underestimate the atmospheric burden of CH4 determined via remote sensing and inversion modelling, pointing to a major gap in our understanding of the contribution of these ecosystems to CH4 emissions. Here we report CH4 fluxes from the stems of 2,357 individual Amazonian floodplain trees from 13 locations across the central Amazon basin. We find that escape of soil gas through wetland trees is the dominant source of regional CH4 emissions. Methane fluxes from Amazon tree stems were up to 200 times larger than emissions reported for temperate wet forests6 and tropical peat swamp forests, representing the largest non-ebullitive wetland fluxes observed. Emissions from trees had an average stable carbon isotope value (δ13C) of −66.2 ± 6.4 per mil, consistent with a soil biogenic origin. We estimate that floodplain trees emit 15.1 ± 1.8 to 21.2 ± 2.5 teragrams of CH4 a year, in addition to the 20.5 ± 5.3 teragrams a year emitted regionally from other sources. Furthermore, we provide a ‘top-down’ regional estimate of CH4 emissions of 42.7 ± 5.6 teragrams of CH4 a year for the Amazon basin, based on regular vertical lower-troposphere CH4 profiles covering the period 2010–2013. We find close agreement between our ‘top-down’ and combined ‘bottom-up’ estimates, indicating that large CH4 emissions from trees adapted to permanent or seasonal inundation can account for the emission source that is required to close the Amazon CH4 budget. Our findings demonstrate the importance of tree stem surfaces in mediating approximately half of all wetland CH4 emissions in the Amazon floodplain, a region that represents up to one-third of the global wetland CH4 source when trees are combined with other emission sources

Flavonoids and a neolignan glucoside from Guarea macrophylla (Meliaceae)

This work describes the phytochemical study of the methanol extract obtained from leaves of Guarea macrophylla, leading to the isolation and identification of three flavonoid glycosides (quercetin 3-O-β-D-glucopyranoside, quercetin 3-O-b-D-galactopyranoside, kaempferol 7-O-β-D-glucopyranoside) and a neolignan glucoside, dehydrodiconiferyl alcohol-4-β-D-glucoside. All compounds were identified by a combination of spectroscopic methods (¹H, 1D, 2D NMR, 13C and UV), ESI-MS and comparison with the literature data. This is the first report of flavonoids in the genus Guarea and of a neolignan glucoside in the Meliaceae family

Composição e estrutura arbórea de um remanescente costeiro de Mata Atlântica no Rio de Janeiro

The Atlantic Forest is one of the richest and most threatened biomes in Brazil. However, the structure and floristic composition of many of its remnants are still unknown. This study assessed the structure and tree composition of the Serra da Tiririca – SET coastal remnant, is the largest remnant in Serra da Tiririca State Park – PESET (Atlantic Forest, RJ). In ten 50 × 20 m plots installed between the edges and the interior of the remnant, we registered 403 trees distributed in 29 families, 59 genera, and 126 species. The richest and most abundant families were Fabaceae, Myrtaceae, and Meliaceae, while the most representative species were Gallesia integrifolia towards the interior of the remnant and Piptadenia gonoacantha towards the edges. The remnant had an average Shannon-Wiener Diversity of 3.69, a total basal area of ​​19.3 m2/ha, and an average diameter and height of 20.42 cm and 11.8 m, respectively. This study shows that the SET remnant is floristically heterogeneous and has distinct structural characteristics and stretches in different successional stages related to edge and interior gradients. Anthropogenic pressures on the remnant are likely to persist and are evidenced mainly by the forest structure.A Mata Atlântica é um dos biomas mais ricos e ameaçados do Brasil. No entanto, a estrutura e composição florística de muitos de seus remanescentes ainda são desconhecidas. Este estudo avaliou a estrutura e a composição arbórea do remanescente costeiro da Serra da Tiririca - SET, o maior remanescente do Parque Estadual da Serra da Tiririca - PESET (Mata Atlântica, RJ). Em dez parcelas de 50 × 20 m instaladas entre as bordas e o interior do remanescente, registramos 403 árvores distribuídas em 29 famílias, 59 gêneros e 126 espécies. As famílias mais ricas e abundantes foram Fabaceae, Myrtaceae e Meliaceae, enquanto as espécies mais representativas foram Gallesia integrifolia para o interior do remanescente e Piptadenia gonoacantha para às bordas. O remanescente apresentou uma diversidade média de Shannon-Wiener de 3,69, uma área basal total de 19,3 m2/ha e diâmetro e altura médios de 20,42 cm e 11,8 m, respectivamente. Este estudo mostra que o remanescente da SET é florísticamente heterogêneo e possui características estruturais distintas e trechos em diferentes estágios sucessionais relacionadas aos gradientes de bordas e interior. De igual forma, este estudo observou que as pressões antrópicas sobre o remanescente tendem a persistir e são evidenciadas principalmente pela estrutura florestal