Estudo do metabolismo de polietileno : desvendando as estratégias metabólicas microbianas envolvidas na biodegradação de plásticos

Tese (doutorado)—Universidade de Brasília, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Programa de Pós-Graduação em Biologia Molecular, 2018.O polietileno (PE) é o polímero sintético mais amplamente utilizado, cuja produção mundial atinge cerca de 150 milhões de toneladas por ano. Como consequência de suas características físico-químicas, o PE é extremamente recalcitrante e resistente ao ataque microbiano, sendo necessários mais de 100 anos para que se decomponha em ambientes naturais. Em virtude da ausência de estratégias eficientes para a gestão dos plásticos pós-consumo, esses materiais inertes acumulam-se nos ecossistemas acarretando dramáticas consequências à sociedade e aos ambientes naturais. Diante do crescente problema imposto pela alta produção desses materiais, foram isoladas a partir de debris plásticos descartados no solo do Cerrado 9 bactérias pertencentes aos gêneros Comamonas, Delftia e Stenotrophomonas capazes de degradar PE de altíssima massa molecular sem a necessidade de pré-tratamentos. Esses isolados apresentaram notáveis atividade metabólica e viabilidade celular após 90 dias de incubação na presença de PE como única fonte de carbono e energia, o que indica que estes são capazes de prosperar por longos períodos expostos a essa condição. As alterações das características físico-químicas e estruturais do PE induzidas pela biodegradação, como composição química, cristalinidade, viscoelasticidade, massa molecular e topografia, foram inferidas por meio do uso de diferentes técnicas espectroscópicas e microscópicas. O perfil químico do PE biodegradado aliado às análises em nível genômico e transcritômico indicam que esses isolados empregam na fragmentação oxidativa desse polímero estratégias metabólicas nunca antes descritas, além do potencial envolvimento de oxidorredutases extracelulares nesta. Uma dessas estratégias é a modificação oxidativa do polímero mediada pela produção biótica de óxido nítrico. Ademais, foram identificadas mais de 15 oxidases potencialmente participantes desse processo degradativo. Até o nosso conhecimento, esse é o primeiro estudo que caracteriza o metabolismo completo de PE em nível celular, o qual foi realizado a partir da integração de abordagens experimentais, genômicas e transcritômicas. O estudo detalhado do metabolismo de PE possibilita a compreensão dos mecanismos moleculares que atuam na biodegradação em nível celular, o que emerge como condição fundamental para o desenvolvimento de estratégias sustentáveis com aplicações práticas na gestão dos resíduos plásticos e na descontaminação dos ambientes naturais, visando à proteção e restauração dos ecossistemas.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq).Polyethylene (PE) is the most utilized synthetic polymer with a global production that exceeds 150 million tons/year. As a consequence of its physicochemical properties, PE-based materials are extremely recalcitrant and inert requires over 100 years to decompose under natural conditions. In an attempt to address this important global issue, we have isolated from the Brazilian Cerrado soil nine novel bacterial strains of Comamonas, Delftia and Stenotrophomonas capable of degrading unpretreated PE of very high molecular weight (191.000). These bacterial strains showed metabolic activity and cellular viability after a 90-day incubation with PE as the sole carbon and energy source, indicating that they can thrive for long periods under such conditions. Changes in PE chemical composition, crystallinity, viscoelasticity, molecular weight and topography induced by these microbes were assessed by different spectroscopic and microscopic approaches. Intriguingly, the biodegraded PE chemical fingerprint, together with genomic and transcriptomic analysis, indicated not only the reported participation of extracellular oxidoreductases in the oxidative fragmentation of this polymer, but also the involvement of yet undescribed biochemical strategies to cope with this process. One such strategy is the oxidation of the polymer, triggered by the biotic production of nitric oxide. Furthermore, we have identified over 15 extracellular oxidases that potentially participate in the biodegradation process. To the best of our knowledge, this is the first study characterizing the metabolism of high molecular weight PE at a cellular level following an integrated experimental, genomic and transcriptomic approach. The detailed study of PE metabolism increases the understanding of the molecular mechanisms underlying its biodegradation, which is critical for the development of sustainable strategies to address the plastic disposal issue and the recovery of harmed natural environments in order to preserve both human and wild lives

Prospecção de microorganismos com potencial para biodegradação de polietileno

Dissertação (mestrado)—Universidade de Brasília, Instituto de Biologia, Departamento de Biologia Celular, Programa de Pós-Graduação em Biologia Molecular, 2013.O polietileno é o polímero sintético mais largamente produzido e utilizado, de modo que sua produção mundial corresponde a aproximadamente 50 milhões de toneladas/ano, mais de um terço da produção total de polímeros sintéticos. Essa elevada produção é justificada pela alta versatilidade, resistência e durabilidade desses materiais, características promissoras para atender à alta demanda da sociedade. No entanto, essas aparentes qualidades consistem em uma dualidade de proporções catastróficas, visto que esses materiais, resistentes e duráveis, levam cerca de 100 a 500 anos para se decompor em ambientes naturais. Diante desse panorama, a sociedade enfrenta crescentes problemas conseqüentes da poluição gerada pela ineficiência das atuais técnicas de gestão desses materiais após seu descarte. Nesse contexto, a biodegradação emerge como alternativa sustentável, pois consiste na mineralização desses materiais mediante submissão ao metabolismo microbiano. Empregando-se técnicas de cultivo, embasadas na utilização de diferentes meios restritivos, foi possível isolar 647 microorganismos a partir de debris plásticos descartados em ambientes naturais. Esses isolados foram pré-selecionados com base em suas capacidades de degradar óleo mineral, alcano assimilável quimicamente semelhante ao polietileno. Os microorganismos que apresentaram esse fenótipo foram submetidos a culturas contendo o polietileno como única fonte de carbono. A fim de detectar indiretamente a ocorrência de biodegradação desse polímero, mensurou-se a viabilidade celular após diferentes períodos de cultivo. A atividade metabólica foi estimada por meio da quantificação do RNA total após o cultivo, além da visualização de microorganismos aderidos ao polietileno previamente corados com os fluoróforos SYTO9® e iodeto de propídio, repórteres de viabilidade celular. Ao todo, três diferentes gêneros de bactérias, Comamonas sp., Deftia sp. e Stenotrophomonas sp., compreendem os nove isolados que se apresentaram como potenciais biodegradadores de polietileno. Em virtude dos resultados encontrados, depreende-se que o presente estudo contribuirá a longo prazo para fornecer um manejo adequado, sustentável e lucrativo a esses materiais pós-consumo. ______________________________________________________________________________________ ABSTRACTPolyethylene is the most consumed synthetic polymer with a current global prodution of 50 million tons per year. This significant production is due to it’s versatility, resistance and durability, promising features in relation to the increasing demand for polyethylene materials. However, these qualities imply an increasing ecological threat to natural environments, since they take from 100 to 500 years to deteriorate under environmental conditions. Consequently, all living organisms increasingly face the severe impact of disposed plastic materials accumulated all over the world. In this context, biodegradation rises as a sustainable alternative to manage these residues, proposing the submittion of these materials to mineralization by microbial metabolisms. By using different cultivation techniques, including cultivation under restrictive conditions, it was possible to isolate 647 microorganisms from plastic debris disposed on natural environments. These isolates were pre-selected based on their capabilities of degrading mineral oil, a relatively short-chain alkane chemically similar to polyethylene. The microorganisms presenting that phenotype were cultivated in restrictive culture medium containing a polyethylene film as the sole carbon source. In order to indirectly detect the polymer degradation, microbial viability was assessed through different periods of cultivation. In addition, metabolic activity was estimated through total RNA quantification, and the cells adhered to the films were visualized by fluorescence microscopy after staining following a fluorescence-based assay for bacterial viability. As a result, three novel bacterial genera, Comamonas sp., Delftia sp. and Stenotrophomonas sp., comprising nine different isolates, were shown to biodegrade polyethylene. Due to these findings, the present study will contribute to a future appropriate, sustainable and profitable management of the post-consume plastic materials

The Hans case and the psychoanalytically oriented education: critical reading of an inaugural experience

Este artigo consiste na releitura do caso clínico do pequeno Hans, problematizando acerca da dificuldade presente na tarefa de educar e tratar simultaneamente uma criança. Mesmo reconhecendo a importância desse estudo para o desenvolvimento da teoria freudiana sobre a sexualidade infantil, nossa discussão recairá sobre o que compreendemos como função "educativa" exercida por Max Graf. Considerando esse caso como uma experiência que inaugura a proposta freudiana de 1933 sobre uma educação psicanaliticamente orientada, conclui-se que, ocupado na função de analista/educador do próprio filho, Graf acaba permitindo o acesso absoluto de Hans à mãe, acentuando seu fracasso enquanto agente da castração.Este artículo consiste en una nueva lectura del caso clínico del pequeño Hans, problematizando acerca de la dificultad presente en la tarea de educar y tratar simultáneamente a un niño. Aun reconocemos la importancia de este estudio para el desarrollo de la teoría freudiana sobre la sexualidad infantil, nuestra discusión recaerá sobre lo que se entiende por "función educativa", ejercida por Max Graf. Considerando este caso como una experiencia que inauguró la propuesta freudiana del 1933 sobre una educación psicoanalíticamente orientada, se concluye que, al ubicarse en la función de analista/educador de su propio hijo, Graf acabó permitiendo el acceso absoluto de Hans a la madre, acentuando su fracaso como agente de castración.This article consists in a new approach to the clinical case of little Hans, questioning the difficult task of educating and simultaneously treating a child. While recognizing the importance of this study for the development of Freud's infantile sexuality theory, our discussion will be on what we understand as the "educational" function of Max Graf. Considering this case as an experience that introduces Freud's 1933 proposal of a psychoanalytically oriented education, it is concluded that, engaged in the function of analyst/educator of his own son, Graf enables the absolute access to Hans' mother, accentuating his failure as the castration agent

Conventional and alternative antifungal therapies to oral candidiasis

Candida-associated denture stomatitis is the most common form of oral candidal infection, with Candida albicans being the principal etiological agent. Candida adheres directly or via an intermediary layer of plaque-forming bacteria to denture acrylic. Despite antifungal therapy to treat denture stomatitis, infection is reestablished soon after the treatment ceases. In addition, many predisposing factors have been identified as important in the development of oral candidiasis, including malnourishment, common endocrine disorders, such as diabetis mellitus, antibacterial drug therapy, corticosteroids, radiotherapy and other immunocompromised conditions, such as acquired immunodeficiency syndrome (AIDS). These often results in increased tolerance to the most commonly used antifungals. So this review suggests new therapies to oral candidiasis.82483

Comparative genomics analyses indicate differential methylated amine utilization trait within members of the genus Gemmobacter

Methylated amines are ubiquitous in the environment and play a role in regulating the earth's climate via a set of complex biological and chemical reactions. Microbial degradation of these compounds is thought to be a major sink. Recently we isolated a facultative methylotroph, Gemmobacter sp. LW‐1, an isolate from the unique environment Movile Cave, Romania, which is capable of methylated amine utilization as a carbon source. Here, using a comparative genomics approach, we investigate how widespread methylated amine utilization is within members of the bacterial genus Gemmobacter. Seven genomes of different Gemmobacter species isolated from diverse environments, such as activated sludge, fresh water, sulphuric cave waters (Movile Cave) and the marine environment were available from the public repositories and used for the analysis. Our results indicate that methylamine utilization is a distinctive feature of selected members of the genus Gemmobacter, namely G. aquatilis, G. lutimaris, G. sp. HYN0069, G. caeni and G. sp. LW‐1 have the genetic potential while others (G. megaterium and G. nectariphilus) have not

DIALÉTICA ENTRE A PRODUÇÃO E O CONSUMO: uma análise histórica das mudanças ideológicas e a ascensão do consumo sustentável

Os grandes avanços tecnológicos e as transformações ocorridas nas esferas social, cultural e econômica entre os séculos XVIII e XXI com o advento da globalização foram responsáveis por alterar consideravelmente as estruturas, modelos e ideologias até então vigentes e influenciar diretamente nos hábitos e comportamentos de consumo da população mundial. Com isso, identificar e analisar tais mudanças podem trazer informações valiosas para o desenvolvimento econômico e social com foco nas gerações futuras. Através de uma revisão da literatura clássica, o objetivo do presente trabalho foi apresentar um panorama histórico das mudanças ocorridas ao longo do tempo na forma de produzir e consumir, além de analisar alguns pontos relativos à ascensão do consumo sustentável, bem como os sujeitos integrantes desse fenômeno

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Design and baseline characteristics of the finerenone in reducing cardiovascular mortality and morbidity in diabetic kidney disease trial

Background: Among people with diabetes, those with kidney disease have exceptionally high rates of cardiovascular (CV) morbidity and mortality and progression of their underlying kidney disease. Finerenone is a novel, nonsteroidal, selective mineralocorticoid receptor antagonist that has shown to reduce albuminuria in type 2 diabetes (T2D) patients with chronic kidney disease (CKD) while revealing only a low risk of hyperkalemia. However, the effect of finerenone on CV and renal outcomes has not yet been investigated in long-term trials. Patients and Methods: The Finerenone in Reducing CV Mortality and Morbidity in Diabetic Kidney Disease (FIGARO-DKD) trial aims to assess the efficacy and safety of finerenone compared to placebo at reducing clinically important CV and renal outcomes in T2D patients with CKD. FIGARO-DKD is a randomized, double-blind, placebo-controlled, parallel-group, event-driven trial running in 47 countries with an expected duration of approximately 6 years. FIGARO-DKD randomized 7,437 patients with an estimated glomerular filtration rate >= 25 mL/min/1.73 m(2) and albuminuria (urinary albumin-to-creatinine ratio >= 30 to <= 5,000 mg/g). The study has at least 90% power to detect a 20% reduction in the risk of the primary outcome (overall two-sided significance level alpha = 0.05), the composite of time to first occurrence of CV death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure. Conclusions: FIGARO-DKD will determine whether an optimally treated cohort of T2D patients with CKD at high risk of CV and renal events will experience cardiorenal benefits with the addition of finerenone to their treatment regimen. Trial Registration: EudraCT number: 2015-000950-39; ClinicalTrials.gov identifier: NCT02545049

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost