Hybridization Capture Using RAD Probes (hyRAD), a New Tool for Performing Genomic Analyses on Collection Specimens.

In the recent years, many protocols aimed at reproducibly sequencing reduced-genome subsets in non-model organisms have been published. Among them, RAD-sequencing is one of the most widely used. It relies on digesting DNA with specific restriction enzymes and performing size selection on the resulting fragments. Despite its acknowledged utility, this method is of limited use with degraded DNA samples, such as those isolated from museum specimens, as these samples are less likely to harbor fragments long enough to comprise two restriction sites making possible ligation of the adapter sequences (in the case of double-digest RAD) or performing size selection of the resulting fragments (in the case of single-digest RAD). Here, we address these limitations by presenting a novel method called hybridization RAD (hyRAD). In this approach, biotinylated RAD fragments, covering a random fraction of the genome, are used as baits for capturing homologous fragments from genomic shotgun sequencing libraries. This simple and cost-effective approach allows sequencing of orthologous loci even from highly degraded DNA samples, opening new avenues of research in the field of museum genomics. Not relying on the restriction site presence, it improves among-sample loci coverage. In a trial study, hyRAD allowed us to obtain a large set of orthologous loci from fresh and museum samples from a non-model butterfly species, with a high proportion of single nucleotide polymorphisms present in all eight analyzed specimens, including 58-year-old museum samples. The utility of the method was further validated using 49 museum and fresh samples of a Palearctic grasshopper species for which the spatial genetic structure was previously assessed using mtDNA amplicons. The application of the method is eventually discussed in a wider context. As it does not rely on the restriction site presence, it is therefore not sensitive to among-sample loci polymorphisms in the restriction sites that usually causes loci dropout. This should enable the application of hyRAD to analyses at broader evolutionary scales.

Ozonólise das ligninas organossolve e kraft eucalipto. Parte II: cinética nos meios ácido e básico

Organosolv and kraft lignins were treated with ozone both in basic and acid media and the reaction was studied kinetically. In contrast to reported studies, ozone was more efective in basic medium. Kraft lignin was degraded faster than organosolv lignin in both media but in the basic medium the rate of reaction was very much faster than in the acid one: for kraft lignin, the observed degradation was 93% for 2 min of reaction in the basic medium and 56% for 10 min of reaction in the acid medium; for organosolv lignin, 47% and 25%, respectively, in the same times. Higher phenolic hydroxyl groups contents increase the reaction rate.

O legado das bifenilas policloradas (PCBs)

Polychlorinated biphenyls (PCBs) are a class of 209 chemical compounds with the molecular formula C12H10-nCl n, where 1 <= n <= 10. They were commercially produced as complex mixtures for various uses, being employed principally as dielectric fluids in capacitors and transformers. They are not easily degraded due their chemical and physical stability and tend to bioaccumulate in the organisms. After the discovery of their xenobiotic activity, restrictions were imposed for their use, as well as for their discards. Nowadays the development of recovery processes for contaminated environment urges to be done due to the extension of reached areas.

Recovery of Hemicelluloses from Wood Hydrolysates by Membrane Filtration

Hemicelluloses are among the most important natural resources that contain polysaccharides. In this study the separation and purification of hemicelluloses from water extraction liquors containing wood hemicelluloses, lignin compounds and monosaccharide by using membrane filtration was investigated. The isolation of the hemicelluloses from the wood hydrolysates was performed in two steps: concentration of high molar mass hemicelluloses by ultrafiltration and separation of low molar mass hemicelluloses from monomeric sugars using tight ultrafiltration membranes. The purification of the retained hemicelluloses was performed by diafiltration. During the filtration experiments, the permeate flux through ultrafiltration and tight ultrafiltration membranes was relatively high. The fouling ability of the used membranes was relatively low. In our experiments, the retention of hemicelluloses using two filtration steps was almost complete. The separation of monosaccharides from hemicelluloses was relatively high and the purification of hemicelluloses by diafiltration was highly efficient. The separation of lignin from hemicelluloses was partially achieved. Diafiltration showed potential to purify retained hemicelluloses from lignin and other organics. The best separation of lignin from hemicelluloses in the first filtration step was obtained using the UC005 membrane. The GE-5 and ETNA01PP membranes showed potential to purify and separate lignin from hemicelluloses. However, the feed solution of the second filtration stages (from different ultrafiltration membranes) affected the permeate flux and the separation of various extracted compounds from hemicelluloses. The GE-5 and ETNA01PP membranes gave the efficient purification of the hemicelluloses when using diafiltration. Separation of degraded xylan from glucomannan (primary spruce hemicelluloses) was also possible using membrane filtration. The best separation was achieved using the GE-5 membrane. The retention of glucomannan was three times higher than xylan retention.

Drosophila melanogaster Meigen: 3. sensibilidade ao carbofuran e biomonitoramento de seus resíduos em repolho

The susceptibility of Drosophila melanogaster to carbofuran and the use of this organism in biomonitoring residues of the insecticide in cabbage was evaluated. Under the conditions of the bioassay, residues-film bioassay in Petri dish, carbofuran degraded depending on the temperature and time of exposure. Bioassays conducted with D. melanogaster showed that its toxicity increases with temperature (20 to 35 °C). LC50 values, calculated as a function of temperature, ranged from 3.6 to 10.5 mg/g body weight (bw) for males and from 2.9 to 8.7 mg/g bw for females. The formulated product Furadan® G was applied on cabbage (Brassica oleracea, var. capitata) and the residues of carbofuran were determined by bioassay. The determination limit of the bioassay was 0.1 mg/kg and the method presented reproducibility with coefficient variation of 17 %. The validation of the bioassay by high performance liquid chromatography confirms the viability of the bioassay with D. melanogaster in monitoring the residues of carbofuran in cabbage.

Estudo da degradação do herbicida ácido 2,4- diclorofenoxiacético (2,4-D) por meio da radiação gama do cobalto-60 em solução aquosa contendo ácido húmico

The use of pesticides in agriculture presents some problems to ecosytems as a consequence of their remaining in the environment. Conventional methods for environmental decontamination sometimes just transfer these residues from one place to another. The use of gamma radiation from cobalt-60 to induce 2,4-D degradation in aqueous solution containing humic acid was studied. Results show that the herbicide is completely degraded after treatment with a 30 kGy dose. There were decreases in the degradation of the 2,4-D when humic acid was added at all doses. Some radiolytic products are proposed. The 2,4-D radiolytic yields (G) from 2,4-D were calculated.

Intracellular membrane trafficking in Osteoclasts The role of direct Rab protein – Rac 1 interactions in the targeting of intracellular vesicles

Osteoclasts are cells responsible for bone resorption. These cells undergo extensive membrane re-organization during their polarization for bone resorption and form four distinct membrane domains, namely the ruffled border, the basolateral membrane, the sealing zone and the functional secretory domain. The endocytic/biosynthetic pathway and transcytotic route(s) are important for the resorption process, since the endocytic/biosynthetic pathway brings the specific vesicles to the ruffled border whereas the transcytotic flow is believed to transport the degraded bone matrix away from the resorption lacuna to the functional secretory domain. In the present study, we found a new transcytotic route from the functional secretory domain to the ruffled border, which may compensate membrane loss from the ruffled border during the resorption process. We also found that lipid rafts are essential for the ruffled border-targeted late endosomal pathways. A small GTP-binding protein, Rab7, has earlier been shown to regulate the late steps of the endocytic pathway. In bone-resorbing osteoclasts it is involved in the formation of the ruffled border, which displays several features of late endosomal membranes. Here we discovered a new Rab7-interacting protein, Rac1, which is another small GTP-binding protein and binds to the GTP-form of Rab7 in vitro. We demonstrated further that Rab7 colocalizes with Rac1 at the fusion zone of the ruffled border in bone-resorbing osteoclasts. In other cell types, such as fibroblast-like cells, this colocalization is mainly perinuclear. Because Rac1 is known to control the actin cytoskeleton through its effectors, we suggest that the Rab7-Rac1 interaction may mediate late endosomal transport between microtubules and microfilaments, thus enabling endosomal vesicles to switch tracks from microtubules to microfilaments before their fusion to the ruffled border. We then studied the role of Rab-Rac1 interaction in the slow recycling pathway. We revealed that Rac1 also binds directly to Rab11 and to some other but not all Rab-proteins, suggesting that Rab-Rac1 interaction could be a general regulatory mechanism to direct the intracellular vesicles from microtubule mediated transport to actin filament mediated transport and vice versa. On the basis of our results we thus propose a new hypothesis for these GTPases in the regulation of intracellular membrane flow.

Distribuição espacial de ferro, cobre e chumbo em sedimentos de manguezal em um gradiente de degradação na Baía de Guanabara (Estado do Rio de Janeiro)

Iron, copper and lead distribution was evaluated in sediment cores from a disturbed mangrove area in Guanabara Bay: a core from a seaward site where mangrove vegetation was removed ~20 yr before sampling (MD); a core from an intermediate site with dead vegetation, apparently due to insect attack (MP), and a core from a landward site with living vegetation (MV). Metal concentrations showed increasing values seaward while organic matter content showed an inverse trend, displaying a negative correlation with metals. This unusual correlation indicates opposite sources, since metals come from the bay and the main OM origin is probably degraded mangrove vegetation. Plant cover loss seems to be a critical factor affecting metal accumulation, particularly due to changes in OM input.

Métodos emergentes para aumentar a eficiência do ozônio no tratamento de águas contaminadas

Many industrial processes produce effluents with a wide variety of xenobiotic organic pollutants, which cannot be efficiently degraded by conventional biological treatments. Thus, the development of new technologies to eliminate these refractory compounds in water has become very imperative in order to assure the quality of this important resource. Ozonation is a very promising process for the treatment of wastewaters containing non-easily removable organic compounds. The present work aims at highlighting new methods of enhancing the efficiency of ozone towards the removal organic pollutants in aqueous solution. Special attention is given to catalytic ozonation processes contemplating homo- and heterogeneous catalysis, their activity and mechanisms. Recent results and future prospects about the application of these processes to real effluents are also evaluated.

River Conservation: Going against the Flow to Meet Global Challenges

Rivers are among the most diverse and threatened ecosystems on Earth, as they are impacted by increasing human pressures. Because rivers provide essential goods and services, conservation of these ecosystems is a requisite for sustainable development. Therefore, we must seek ways to conserve healthy rivers and to restore degraded ones

Ocorrência e atividade biológica de quassinóides da última década

Quassinoids, the bitter principles of the Simaroubaceae family, are a group of structurally complex and highly oxygenated degraded triterpenes. They are divided into five groups according to their basic skeleton, C-18, C-19, C-20, C-22 and C-25. In recent years, attention has been focused on quassinoids because several of them have shown promising biological activities. This paper features a review of some characteristics of these compounds, updating known information with discoveries from the last decade and covering chemical structures, basic skeletons, occurrence in genus and species, besides detailed studies of biological activities such as antitumor, antimalarial, phytotoxic, antifeedant, insecticidal, anti-inflammatory and antiulcer.

Efeitos dos parâmetros operacionais na fotodegradação do azo corante direct red 23 na interface dióxido de titânio/água

The decolorization and degradation of direct red 23 azo dye have been investigated in aqueous suspension of titanium dioxide under artificial irradiation. The effects of some operational parameters such as azo dye concentration, catalyst loading, and solution pH were investigated at 30.0 ºC and optimized values were obtained. The first-order kinetic model was used to discuss the results. The UV-Vis spectra changes showed that the azo dye sample, collected after 6 h irradiation, was 98% decolorized while the residual total carbon was 97.9% degraded, indicating simultaneous photodecolorization and degradation.

Degradação de corantes ácidos por processos oxidativos avançados usando um reator com disco rotatório de baixa velocidade

Three technologies were tested (TiO2/UV, H2O2/UV, and TiO2/H2O2/UV) for the degradation and color removal of a 25 mg L-1 mixture of three acid dyes: Blue 9, Red 18, and Yellow 23. A low speed rotating disc reactor (20 rpm) and a H2O2 concentration of 2.5 mmol L-1 were used. The dyes did not significantly undergo photolysis, although they were all degraded by the studied advanced oxidation processes. With the TiO2/H2O2/UV process, a strong synergism was observed (color removal reached 100%). Pseudo first order kinetic constants were estimated for all processes, as well as the respective apparent photonic efficiencies.

Influência da luz e da temperatura sobre a oxidação do óleo essencial de capim-limão (Cymbopogon citratus (D.C.) Stapf)

The identification of the chemical compounds of the essential oil was performed with a gas chromatograph coupled to a mass spectrometer. The oil was left in the presence and absence of light and submitted to different temperatures to evaluate its stability. The yields of the major compounds were evaluated every fifteen days. Citral and myrcene, the major compounds of the essential oil, were degraded over time in both the presence and absence of light, but temperature only influenced the degradation of myrcene.

Constituintes químicos e atividade inseticida dos extratos de frutos de Trichilia elegans E T. catigua (Meliaceae)

Phytochemical investigation of the fruits extracts of Trichilia elegans and Trichilia catigua (Meliaceae) has led to the identification of the limonoids 11β-acetoxyobacunone, cedrelone, methylangolensate and epimeric mixture of photogedunin besides known coumarins (scoparone, scopoletin, umbeliferone) and the steroids stigmasterol, β-sitosterol, sitostenone and campesterol. The structures of the compounds were proposed by spectroscopic analysis and comparison with literature data. An evaluation of the insecticidal activity of the fruits extracts of Trichilia ssp. was carried out and the extracts of T. elegans revealed to have strong insecticidal activity and the extracts of T. catigua showed moderate larval mortality on Spodoptera frugiperda.