Emissões naturais e antrópicas de metais e nutrientes para a bacia inferior do rio de contas, Bahia

Emission factors of anthropogenic activities and natural processes were used to estimate nutrients and metals loads to the Contas River lower basin, Southern Bahia, Brazil. Among natural sources, emission from soil leaching is larger for N, Cu and Pb. Atmospheric deposition is the major natural source of P, Zn, Cd and Hg. Among anthropogenic sources, agriculture is the major source of N, Cu and P. Urban sources are the major contributors to the other elements. Present anthropogenic land uses are already responsible for 78 and 99% of total N and P loads and about 50% of total Cu and Hg.

Sistema limpo em linha para extração em fase sólida de contaminantes emergentes em águas naturais

A solid-phase in-line extraction system for water samples containing low levels of emerging contaminants is described. The system was specially developed for large volume samples (up to 4 L) using commercial solid-phase extraction (SPE) cartridges. Four sets containing PTFE-made connectors, brass adapters and ball valves were used to fit SPE cartridges and sample bottles to a 4-port manifold attached to a 20 L carboy. A lab-made vacuum device was connected to the manifold cap. The apparatus is robust and less expensive than the typical available system. Its also provides less experimental handling, avoiding cross contamination and sample losses.

Em busca da sustentabilidade: células solares sensibilizadas por extratos naturais

The present work reports the use of anthocyanins extracted from mulberry (Morus Alba L.), raspberry (Rubus Idaeus L.) and blueberry (Vaccinium myrtillus L.) as sensitizers in dye-sensitized solar cells. The conversion efficiency of these devices is dependent on the extracts employed and can be rationalized in terms of their composition and spectral properties. Solar cells sensitized by the mulberry extract showed the highest efficiency among the fruits investigated. Moreover, a 16 cm² active area solar cell with the mulberry extract has presented fair good efficiency of conversion for natural dye-based solar cells, besides stability over twenty weeks, showing perspectives for developing these low cost devices with a commercial viability.

Estrogênios em águas naturais e tratadas da região de Jaboticabal - São Paulo

The aim of this work was to analyze 17 β estradiol and estrone, natural estrogenic hormones present in domestic effluents and animal excreta, in the public water supply system of Jaboticabal, SP. The results have shown the presence of estrogens in 22% of the samples in concentrations from 6,8 ng L-1 (treated water) to 30,6 ng L-1 (riverhead) for 17 β estradiol and 600 ng L-1 of estrone (stream), respectively. We concluded that animal wastes, discharges from the wastewater treatment station, and discharges of domestic effluent without treatment from rural proprieties were probably the cause of this contamination.

Utilização de detecção por espalhamento de luz evaporativo para a análise de produtos naturais

The interest in the use of evaporative light scattering detector (ELSD) for the analysis of different classes of natural products has grown over the years. This is because this detector has become an excellent alternative compared to other types of detectors, such as the refractive index detector and the ultraviolet (UV) detector. This review describes the basic principles of ELSD functioning and discusses the advantages and disadvantages in using an ELSD for the analysis of organic compounds. Additionaly, an overview, covering the last 23 years, of ELSD applications in natural products analysis (saponins, terpenes, carbohydrates, glycosides, alkaloids, steroids, flavonoids, peptides, polyketides, coumarins and iridoids) is presented and discussed.

Processos naturais de biodegradação do petróleo em reservatórios

Petroleum biodegradation in reservoirs is a process caused by different microorganisms affecting many oil deposits which modifies the oil composition in a quasi-stepwise process starting from n-alkanes and isoprenoids through to diasteranes. This causes oil souring and increased viscosity, sulfur and metal content, having a direct impact on oil production and refining costs.

Emissões naturais e antrópicas de nitrogênio, fósforo e metais para a bacia do Rio Macaé (Macaé, RJ, Brasil) sob influência das atividades de exploração de petroleo e gás na Bacia de Campos

Emission factors of natural processes and anthropogenic activities were used to estimate nutrients and metal loads for the lower Macaé river basin, which hosts the operational base for the offshore oil and gas exploration in the Campos Basin. The estimates indicated that emissions from anthropogenic activities are higher than natural emissions. Major contributing drivers include husbandry and urbanization, whose effluents receive no treatment. The increasing offshore oil exploration along the Brazilian littoral has resulted in rapid urbanization and, therefore might increase the inshore emission of anthropogenic chemicals in cases where effective residue control measures are not implemented in fluvial basins of the region.

Drogas de abuso em águas naturais e residuárias urbanas: ocorrência, determinação e aplicações forenses

Drugs of abuse are commonly used outside medical or legal settings where their production, marketing and consumption are subject to legal summons and/or intervention. Classified as emerging contaminants, these substances have been recently detected in samples of environmental concern, such as waters and wastewaters. This review presents the state-of-the-art on the methodological approaches used in sample preparation, the main techniques applied in analytical determination at trace levels, as well as the use of information related to the drug or its metabolite concentration in sewage samples to empirically estimate the consumption of drugs of abuse in a city or region.

Explorando produtos naturais microbianos nas fronteiras da Química e da Biologia

The chemistry of natural products has been remarkably growing in the past few decades in Brazil. Aspects related to the isolation and identification of new natural products, as well as their biological activities, have been achieved in different laboratories working on this subject in the country. More recently, the introduction of new molecular biology tools has strongly influenced the research on natural products, mainly those produced by microorganisms, creating new possibilities to assess the chemical diversity of secondary metabolites. This paper describes some ideas on how the research on natural products can have a considerable input from molecular biology in the generation of chemical diversity. We also explore the role of microbial natural products in mediating interspecific interactions and their relevance to ecological studies. Examples of the generation of chemical diversity are highlighted by using genome mining, mutasynthesis, combinatorial biosynthesis, metagenomics, and synthetic biology, while some aspects of microbial ecology are also discussed. The idea to bring up this topic is linked to the remarkable development of molecular biology techniques to generate useful chemicals from different organisms. Here, we focus mainly on microorganisms, even though similar approaches have also been applied to the study of plants and other organisms. Investigations in the frontier of chemistry and biology require interactions between different areas, characterizing the interdisciplinarity of this research field. The necessity of a real integration of chemistry and biology is pivotal to finding correct answers to a number of biological phenomena. The use of molecular biology tools to generate chemical diversity and control biosynthetic pathways is largely explored in the production of important biologically active compounds. Finally, we briefly comment on the Brazilian organization of research in this area, the necessity of new strategies for the graduation programs, and the establishment of networks as a way of organization to overcome some of the problems faced in the area of natural products.

VALIDAÇÃO INTRALABORATORIAL DA DETERMINAÇÃO DE METILTESTOSTERONA EM ÁGUAS NATURAIS POR VOLTAMETRIA USANDO ELETRODO DE GOTA PENDENTE DE MERCÚRIO

17α-methyltestosterone (17α-MT) is a hormone used in medicine and aquaculture which can be found in natural waters. It is considered an emerging organic pollutant and its accurate and precise analysis is required. Therefore, this study presents the in-house validation of a new voltammetric methodology for 17α-MT analysis in natural waters. A hanging mercury drop electrode and NaOH 5.0×10-3 mol L-1 solution as the electrolyte were employed in the voltammetric determinations. To confirm the presence of 17α-MT in water samples quantitative analysis was performed by ESI-MS/MS. The methodology exhibited good selectivity, linearity, accuracy (recovery of between 100.4 and 108.8%) and precision (RSDs for repeatability of 2.85% and for intermediate precision of 14.10%, with n = 5, respectively). LOD and LOQ were 3.07 µg L-1 and 10.78 µg L-1, respectively. The methodology was suitable for determination of 17α-MT in natural waters due to low-cost, good performance and no sample pre-treatment required.

CÉLULAS SOLARES SENSIBILIZADAS POR CORANTES NATURAIS: UM EXPERIMENTO INTRODUTÓRIO SOBRE ENERGIA RENOVÁVEL PARA ALUNOS DE GRADUAÇÃO

An interesting practical experiment about the preparation of dye–sensitized solar cells (DSSC) using natural dyes were carried out by the undergraduate students in the chemistry course at UNICAMP . Natural dyes were extracted from blueberries (Vaccinium myrtillus L.), jabuticabas (Myrciaria cauliflora), raw and cooked beets (Beta vulgaris L.), and annattos (Bixa orellana L.), which were used to sensitize TiO2 films that composed the photoanode in the DSSC. A polymer electrolyte containing an iodide/triiodide redox couple was used in lieu of the use of liquid solutions to prevent any leakage in the devices. A maximum solar-to-electric energy conversion of 0.26 ± 0.02% was obtained for the solar cell prepared with annatto extracts. This experiment was an effective way to illustrate to the undergraduate students how to apply some of the chemical concepts that they learned during their chemistry course to produce electric energy from a clean and renewable energy source. Teachers could also exploit the basics of the electronic transitions in inorganic and organic compounds (e.g., metal-to-ligand charge transfer and ϖ-ϖ* transitions), thermodynamics (e.g., Gibbs free energy), acid–base reactions in the oxide solid surface and electrolyte, and band theory (i.e., the importance of the Fermi level energy).

Eclosão e mortalidade de Meloidogyne exigua em extratos e em produtos naturais

A eclosão e mortalidade de juvenis de segundo estádio (J2) de Meloidogyne exigua foram avaliadas em extratos aquosos de urucum-colorau (Bixa orellana), cravo-da-índia (Syzygium aromaticum), canela (Cinnamomum zeylanicum), pimenta-do-reino (Piper nigrum), gengibre (Zingiber officinale), salsa (Petroselium crispum), soro de leite, solução nutritiva hidropônica, solução aquosa de cloreto de sódio (NaCl) e açúcar (sacarose), fermento biológico e probiótico (Controlmix®). O soro de leite e os extratos de canela, fermento biológico e cloreto de sódio causaram 100% de mortalidade (P<0,05) após 24 h do contato dos J2 com os extratos. Mortalidade acima de 50% também ocorreu nos extratos de cravo-da-índia e no probiótico. Os demais materiais testados foram estatisticamente iguais à água (P<0,05). A eclosão foi avaliada durante 16 dias de imersão dos ovos de M. exigua nos extratos. Comparando os valores da área abaixo da curva de progresso da eclosão, observou-se que, exceto o açúcar e a solução hidropônica, todos os extratos e produtos testados inibiram a eclosão (P<0,01) dos J2 de M. exigua. Entre todos os extratos e produtos testados, maior inibição (P<0,01) da eclosão ocorreu no soro de leite, probiótico, canelaecravo-da-índia, destacando-se o soro de leite e o extrato de canela que assim como inibiram a eclosão também foram altamente tóxicos aos juvenis.

Efeito de dois indutores de resistência sobre a severidade do mal-do-Panamá

O mal-do-Panamá, causado por Fusarium oxysporum f. sp. cubense, é um fator limitante à cultura da bananeira (Musa spp.). A medida de controle mais eficiente para essa doença é o cultivo de variedades resistentes. A resistência induzida constitui alternativa a ser avaliada nesse patossistema. Avaliou-se o efeito indutor de resistência de acibenzolar-S-metil (ASM) e ácido DL-b-amino-n-butírico (BABA) sobre germinação e crescimento micelial de F. oxysporum f. sp. cubense in vitro nas dosagens 0; 0,050; 0,100; 0,150; 0,200; 0,250 e 0,500 mg.ml-1 e 0; 0,525; 1,050; 1,575; 2,100; 2,625 e 3,150 mg.ml-1, respectivamente, utilizando-se F. oxysporum f. sp. cubense na concentração 1 x 10³ conídios.ml-1. Os ASM e BABA foram pulverizados nas dosagens 0; 0,050; 0,100; 0,150; 0,200; 0,250 mg.ml-1 e 0; 0,525; 1,050; 1,575; 2,100; 2,625 mg.ml-1, respectivamente, sobre bananeiras 'Maçã' e 'Grande Naine' micropropagadas, mantidas em casa de vegetação. As raízes foram inoculadas por imersão em suspensão de F. oxysporum f. sp. cubense 1 x 10³ conídios.ml-1, quatro, seis e oito semanas após indução. Avaliou-se a severidade da doença 20 dias após inoculação através de escala de notas. O BABA, 2,100 mg.ml-1, propiciou 35,29% de redução na severidade de doença em banana 'Maçã', aplicado quatro semanas antes da inoculação com F. oxysporum f. sp. cubense. O ASM, 0,500 mg.ml-1, inibiu a germinação de conídios in vitro. O BABA, nas dosagens testadas, não interferiu no crescimento micelial. Em 'Grande Naine', BABA, 0,525 mg.ml-1, reduziu a severidade da doença em 21,55% independente da época de inoculação. Não se constatou efeito do ASM sobre a severidade do mal-do-Panamá.

Indução de resistência a Fusarium oxysporum f. sp. Tracheiphilum em Caupi: eficiência de indutores abióticos e atividade enzimática elicitada

Foram avaliados os efeitos de indutores abióticos em cultivares de caupi inoculadas com Fusarium oxysporum f. sp. tracheiphilum quanto à severidade, controle da doença e atividade enzimática. Para isso, plantas das cultivares IPA-206 e BR-17 Gurguéia com cinco dias de idade foram pulverizadas com soluções aquosas de ASM (5,0 g do i.a./100 L de água), BABA (1,5 mM) e quitosana (2,0 mg/mL), no primeiro par de folhas e inoculadas, após sete dias da germinação, com 20 mL de uma suspensão de 1 x 10(6) conídios/mL do isolado ISO-PE. A avaliação da severidade da doença foi realizada aos 25 dias após a germinação, através de escala de notas e índice de doença. As atividades das enzimas beta-1,3-glucanase, peroxidase e fenilalanina amônia liase (PAL) foram determinadas em plantas submetidas aos tratamentos anteriores, coletadas aos cinco e 10 dias após a inoculação. Foi observada diferença significativa entre os indutores e a testemunha, nas duas cultivares testadas, aos cinco e 10 dias, destacando-se o indutor ASM, proporcionando um controle da doença de 68,90% e 71,59% nas cultivares BR-17 Gurguéia e IPA-206, respectivamente. O indutor ASM apresentou melhores resultados nas atividades de beta-1,3-glucanase, peroxidase e PAL, destacando-se na cultivar IPA-206 nos dois períodos analisados. Os indutores BABA e quitosana diferiram da testemunha, na atividade de PAL e beta-1,3-glucanase, nessa mesma cultivar, aos cinco dias após a inoculação.