RESUMEN
Heterobostrychus aequalis (Waterhouse, 1884) (Coleoptera: Bostrichidae) is considered a severe pest for wood and wood products in regions where it is established. In Brazil, so far, there are no records of its establishment. Therefore, this work reports the interception of this Bostrichidae in the Harbor of Rio de Janeiro, on pallet wood from India. It also defends the maintenance of this insect as an absent quarantine pest (A1), by the Ministry of Agriculture, Livestock and Supply. It also conducts a discussion that addresses the efficiency of wood treatments, usually used to prevent the spread of quarantine pests in environments where there is international transit of wood, demonstrating that they may not be efficient in this regard, especially for insect species that have the capacity to lay eggs on dry wood. In this context, it also suggests population monitoring, combined with inspections, as an aid measure for the early detection of this pest in an environment where there is international transit of wood.
Asunto(s)
Madera/parasitología , Escarabajos , Bromuros/administración & dosificación , Control de Plagas/métodos , Brasil , Saneamiento de PuertosRESUMEN
Selection of monomer couples, ensuring reactivity ratios close to zero, is an effective strategy to induce spontaneous copolymerization into an alternating sequence. In addition, monomer design and customisation of the solvent-monomer interactions open the way to functional copolymers showing molecular self-assembly relevant to their regular amphipathic structure. In this work, we show that the design of comonomers with adequate reactivities and interactions can be used to direct copolymer self-assembly on a mesoscopic scale. We investigate spontaneous formation of nanoparticles through solvent/non-solvent interactions using the so-called "ouzo effect". In this way, an ouzo diagram was built to determine the operation window for the self-assembly, in aqueous suspensions, of alternating copolymers consisting of vinyl phenol and maleimide units carrying long alkyl-pendant groups (C12H25 or C18H37). Also, investigations were pursued to account for the influence of the lateral lipophilic pendant units on the size and structure of the nanoaggregates formed during one-shot water addition. Structure characterisation by light scattering techniques (DLS and SLS), small-angle neutron scattering (SANS) and transmission electron microscopy (cryo-TEM and TEM) confirmed the self-assembly of copolymer chains into nanoparticles (size range: 60-300 nm), the size of which is affected by the lipophilicity of the alternating copolymers, solvent-water affinity and the solvent diffusion in water. Altogether, we present here the spontaneous ouzo effect as a simple method to produce stable alternating copolymer nanoparticles in water without the addition of stabilizing agents.
RESUMEN
Bark and ambrosia beetles, mainly the ones belonging to groups Scolytinae, Bostrichidae and Platypodinae, can kill trees from reforestation areas or native forests and damage the wood. Population monitoring and the identification of quarantine species are carried out by assembling ethanol-baited traps. The aims of the current study are to evaluate the influence of the color of ethanol-baited traps on the efficient capture of these insects, as well as to measure changes in colorimetric variables based on trap exposure in the field and to investigate whether these changes affect capture efficiency. Eight ethanolic traps (red, yellow, black and transparent traps - two of each color) were installed in a forest fragment in the first experimental stage samples were collected on a weekly basis, for 11 months. New and used transparent traps were installed in the field in the second experimental stage - samples were collected for additional 11 months. A portable spectrophotometer was used to measure the colorimetric variables in these traps. The mean number of Scolytinae individuals (± SD) captured in transparent traps (48±50) was significantly higher than that of individuals captured in black (24±25), yellow (23±21) and red (22±21) traps. However, transparent traps subjected to field conditions were colonized by such as fungi, bacteria and mosses, which changed the transparent state of the traps into a darkened color and significantly affected their capture efficiency. The total number of 6,268 Scolytinae individuals were collected at this experimental stage: 4,977 of them were captured in new traps, whereas 1,291 were captured in the old ones. Based on the herein measured colorimetric variables, such color change got significantly intensified as transparent traps remained under field conditions. In conclusion, transparent traps were more efficient in capturing Scolytinae individuals than the black, yellow and red traps. In addition, the exposure to field conditions has progressively changed equipment color and decreased its capture efficiency.
Asunto(s)
Escarabajos , Control de Plagas/métodos , Gorgojos , EntomologíaRESUMEN
Scolytinae is a beetle group belonging to Order Coleoptera; these insects play an essential role in wood degradation in forest ecosystems, since they build galleries that enable substrate colonization by other saprophytic organisms, as well as nutrient cycling. Thus, the aim of the current study was to evaluate the occurrence of Scolytinae in the wood of 5 tree species exposed to mangrove environment, as well as to simultaneously survey Scolytinae specimens captured in ethanol-baited impact traps placed in the same environment. The study was carried out in a mangrove area located in Santa Cruz neighborhood - RJ. Five freshly-harvested Clitoria fairchildiana, Rhyzophora mangle, Corymbia citriodora, Melia azedarach and Eucalyptus pellita wood logs (1 m long and 5-10 cm diameter) were arranged perpendicular to the ground (1 m above it) and spaced 30 cm away from each other. Five impact traps were set up 50 m away from each other, 1.3 m above the ground. Insects were collected for 5 months. One hundred and thirty (130) Scolytinae individuals (14 species in 2 genera) were recorded in the wood logs; the relative frequency (Fr) of the species comprised Xyleborus affinis (33.9%) and Hypothenemus sp.4 (17.7%), which represented 51.6% of the total number of captured individuals. Hypothenemus sp.6 specimens were not collected in ethanol-baited traps, but the wood of C. fairchildiana. E. pellita did not show insect infestation. The traps captured 798 individuals (24 species belonging to 8 genera); the frequency of X. affinis (25.3%) and Hypothenemus eruditus (14.5%) represented 39.8% of the total number of captured insects.
Scolytinae é um grupo da Ordem Coleoptera que tem função importante na degradação da madeira em ecossistemas florestais, através da construção de galerias, facilitam a colonização por outros organismos saprófitas neste substrato, auxiliando a ciclagem de nutrientes. Nesse contexto, este trabalho teve como objetivo avaliar à ocorrência de Scolytinae na madeira de cinco espécies arbóreas expostas em ambiente de mangue, bem como realizar simultaneamente, o levantamento dos escolitíneos capturados por armadilha de impacto iscada com etanol no mesmo ambiente. O estudo foi realizado numa área de manguezal, no Bairro de Santa Cruz-RJ. Cinco toras de madeira recém abatidas de Clitoria fairchildiana, Rhyzophora mangle, Corymbia citriodora, Melia azedarach e Eucalyptus pellita, de 1 m e diâmetro variando 5-10 cm, foram dispostas perpendicularmente ao solo a uma altura de 1 m e espaçadas de 30 cm. Cinco armadilhas de impacto foram instaladas a uma distância de 50 m entre si a uma altura de 1,3 m em relação ao solo. Os insetos foram coletados durante o período de 5 meses. Nas madeiras, registrou-se 130 indivíduos de Scolytinae (14 espécies em 2 gêneros) cuja frequência relativa (Fr) das espécies foi: Xyleborus affinis Eichhoff (33,9%) e Hypothenemus sp.4 (17,7%) representando 51,6% do total de indivíduos capturados. Hypothenemus sp.6 não foi coletada em armadilha etanólica, sendo capturada na madeira de C. fairchildiana. Em E. pellita não houve infestação. Nas armadilhas foram capturados 798 indivíduos (24 espécies em 8 gêneros), cuja a Fr de X. affinis(25,3%) e Hypothenemus eruditus Westwood(14,5%) representou 39,8%.
Asunto(s)
Escarabajos , Bosques , Entomología , HumedalesRESUMEN
Pachira aquatica (Malvaceae), known as munguba, is cultivated for afforestation of many Brazilian cities. In Seropédica campus of UFRRJ, it was observed the defoliation of one specimen of Pachira aquatica with presence of larvae, pre-pupae, and pupae of beetle of the subfamily Hyperinae, which were reared in laboratory until the emergence of the adults; these insects were identified as belonging to the species Phelypera griseofasciata Capiomont (Coleoptera: Curculionidae). These immature forms (n=86) were again collected in this same specimen and reared in laboratory to verify the occurrence of parasitism. It was obtained 128 adults of Jaliscoa nudipennis Boucek (Hymenoptera: Pteromalidae), responsible for 44.2% of total parasitism. The sex ratio was 0.70, so the highest number of offspring was of females. Intersexual and intrasexual dimorphisms were also observed in J. nudipennis regarding the shape of the head and characteristics of the wings. This study is the first record of both insect species associated with Pachira aquatica in the state of Rio de Janeiro, Brazil.(AU)
Pachira aquatica (Malvaceae), conhecida como munguba, é cultivada para arborização de muitas cidades brasileiras. No campus de Seropédica da UFRRJ, observou-se o desfolhamento de um espécime de Pachira aquatica, com a presença de larvas, pré-pupas e pupas de besouro da subfamília Hyperinae, que foram criadas em laboratório até a emergência dos adultos; esses insetos foram identificados como pertencentes à espécie Phelypera griseofasciata Capiomont (Coleoptera: Curculionidae). Essas formas imaturas (n=86) foram novamente coletadas nesse mesmo espécime e criadas em laboratório para verificar a ocorrência de parasitismo. Foram obtidos 128 adultos de Jaliscoa nudipennis Boucek (Hymenoptera: Pteromalidae), responsáveis por 44,2% do parasitismo total. A razão sexual foi de 0,70, portanto, o maior número de descendentes foi de fêmeas. Observaram-se ainda os dimorfismos inter e intrasexuais em J. nudipennis quanto ao formato da cabeça e às características das asas. Este estudo trata-se do primeiro registro de ambas as espécies de insetos associadas a Pachira aquatica no estado do Rio de Janeiro, Brasil.(AU)
Asunto(s)
Escarabajos , Bombacaceae , Enfermedades Parasitarias , Pupa , Árboles , InsectosRESUMEN
Wood is rich in organic compounds; thus, it is susceptible to attacks by several deteriorating agents because they acknowledge such attacks as a necessary energy supply. Fungi stand out among these agents since they can attack the wood in trees (before felling) and in several post-felling stages. Fungi are biological agents that use organic compounds as food sources, and that is the reason why they degrade most chemical components found in wood. Wood attacked by fungi suffers significant value loss, since these degrading agents affect their mechanical and aesthetic properties. Fungi which are classified as staining, molding and rotting are one of the main responsible for the biggest losses in the timber industry. Wood can be virtually used in a whole range of environments, a fact that makes it susceptible to attacks by different fungal species, since the ideal conditions for fungal development change from species to species. In other words, the fact that one or more fungal species are capable of deteriorating wood is directly related to conditions wood is subjected to. Thus, it is essential knowing how to evaluate fungal attacks, symptoms to be taken into consideration at the time to identify the type of attacking organism and the attack stage, as well as the control and prevention measures to be applied to these organisms.(AU)
Rica em compostos orgânicos, a madeira é suscetível ao ataque de diversos agentes deterioradores por ser reconhecida como suprimento necessário de energia. Entre esses agentes, destacam-se os fungos, cujo início de ataque pode se dar ainda na árvore, antes do abate e nas diversas fases posteriores. Os fungos são agentes biológicos que necessitam de compostos orgânicos como fontes de alimento e, por essa razão, degradam grande parte dos componentes químicos da madeira. As madeiras, quando atacadas por fungos, sofrem grandes perdas de valor, afetando suas propriedades mecânicas e estéticas. Os fungos são considerados um dos principais responsáveis pelos maiores prejuízos na indústria madeireira e são classificados como manchadores, emboloradores e apodrecedores. Praticamente, a madeira pode estar em uso em uma variedade de ambientes; sabendo-se que as condições ideais de desenvolvimento de um fungo são diferentes para cada espécie, a madeira ficará suscetível ao ataque por diferentes espécies de fungos. Ou seja, o fato de uma ou mais espécies de fungos serem encontradas deteriorando a madeira está diretamente relacionado às condições em que ela se encontra. Dessa forma, torna-se importante saber como avaliar os ataques feitos por fungos, os sintomas a serem considerados para identificar o tipo de organismo e o estágio do ataque, bem como as medidas de controle e prevenção desses organismos.(AU)
Asunto(s)
Madera , Hongos , Compuestos Orgánicos , Árboles , Factores Biológicos , Ambiente , Abastecimiento de EnergíaRESUMEN
Bemisia tabaci has been known in Brazil since 1923, in cotton, soybean, tomato and bean crops, and it leads to economic losses due to the transmission of different viruses. Studies focused on analyzing the incidence of this pest in forest environments remain scarce in the literature. Thus, the aims of the current study were to investigate the incidence of B. tabaci in four Atlantic forest fragments in Rio de Janeiro state, Brazil, as well as to record its hosts in these environments. An area of approximately one hectare was delimited for each Atlantic forest fragment based on images provided by the Brazilian Institute of Geography and Statistics (IBGE). Plants presenting whiteflies were tagged throughout monthly inspections conducted in each forest fragment in order to be checked during the following visits. Collection criteria were adopted to assure sampling standardization in each fragment. The mean number of whiteflies was analyzed through the Kruskal-Wallis non-parametric test, which was followed by Dunn's post-hoc test, both at 5% significance level. The total of 216 collections were conducted and 1,126 B. tabaci fourth-instar nymphs were collected in four Atlantic forest fragments over 24 months. The following hosts were recorded for the first time: Caesalpinia pluviosa Benth, Tradescantia zebrina Linn., Impatiens walleriana Linn., Cupania sp. and Talisia esculenta Klotzsch & O. Berg. The dry period (winter) enabled the increase of B. tabaci populations in the herein investigated forest fragments.(AU)
Bemisia tabaci é conhecida no Brasil desde 1923, relatada em cultivos de algodão, soja, tomate e feijoeiro, promovendo prejuízos econômicos por ser transmissora de viroses. São praticamente inexistentes os trabalhos que analisam sua ocorrência em ambiente florestal. Nesse sentido, o objetivo deste trabalho foi estudar a ocorrência de B. tabaci em quatro fragmentos florestais de Mata Atlântica no estado do Rio de Janeiro, bem como registrar seus hospedeiros nesses ambientes. Em cada fragmento de Mata Atlântica foi demarcada uma área com cerca de um hectare, delimitada com o uso de imagens obtidas do Instituto Brasileiro de Geografia e Estatística (IBGE). Ao longo das inspeções mensais nos fragmentos florestais, os vegetais que apresentavam moscas-brancas foram marcados e inspecionados a toda nova visita. Adotaram-se critérios de coleta para garantir padronização do esforço amostral em todos os fragmentos. A análise do número médio de moscas-brancas foi feita pelo teste não paramétrico de Kruskal-Wallis, com posterior aplicação do pós-teste de Dunn, ambos a 5% de significância. Foram realizadas 216 coletas e capturadas 1.126 ninfas de quarto instar de B. tabaci nos quatro fragmentos de Mata Atlântica ao longo dos 24 meses. Registraram-se, pela primeira vez, os hospedeiros: Caesalpinia pluviosa Benth, Tradescantia zebrina Linn., Impatiens walleriana Linn., Cupania sp. e Talisia esculenta Klotzsch & O. Berg. O período seco (inverno) promove estímulos para o aumento da população de B. tabaci em fragmentos florestais.(AU)
Asunto(s)
Bosques , Hemípteros , Impatiens , Caesalpinia , TradescantiaRESUMEN
Studies that analyze the occurrence of whiteflies in forest environments are virtually non-existent, which is not justifiable given the ecological and agronomic importance of this insect group. The study aimed to evaluate the occurrence of Aleyrodidae collected from May/2013 to May/2014 in three Atlantic forest fragments in state of Rio de Janeiro, Brazil. Of all, 1,212 puparia were collected, and five genera and seven species of whiteflies occurring in nine hosts were identified. Aleuropleurocelus cecropiae was the only aleyrodid registered simultaneously occurring in Cecropia hololeuca in the three environments, with lower records in the two fragments considered as less anthropized. For the first time, Aleurothrixus floccosus was registered on Handroanthus ochraceus and Mangifera indica. In addition, it was observed the first register of Bemisia tabaci on Commelina benghalensis and Caesalpinia pluviosa. Minutaleyrodes minuta on Syzygium cumini was also the register of a new occurrence.(AU)
São praticamente inexistentes os trabalhos que analisam a ocorrência de moscas-brancas em ambientes florestais, o que não é justificável, em vista da importância ecológica e agronômica desse grupo de insetos. Objetivou-se avaliar a ocorrência de Aleyrodidae em três fragmentos de Mata Atlântica no estado do Rio de Janeiro, no período entre maio/2013 e maio/2014. Propõe-se chave taxonômica para cinco gêneros. Coletaram-se 1.212 pupários e identificaram-se cinco gêneros e sete espécies de moscas-brancas ocorrendo em nove hospedeiros. Aleuropleurocelus cecropiae foi o único aleirodídeo registrado simultaneamente, ocorrendo em Cecropia hololeuca, nos três ambientes avaliados, com registros inferiores nos dois fragmentos considerados menos antropizados. Ainda, registrou-se pela primeira vez Aleurothrixus floccosus em Handroanthus ochraceus e em Mangifera indica. Também se procedeu ao primeiro registro de Bemisia tabaci em Commelina benghalensis e Caesalpinia pluviosa. Minutaleyrodes minuta sobre Syzygium cumini é, igualmente, o registro de uma nova ocorrência.(AU)
Asunto(s)
Bosques , Cecropia , Hemípteros , Tabebuia , Caesalpinia , SyzygiumRESUMEN
Three new isoaigialones, A, B, and C (1-3), along with aigialone (4), were isolated from the crude EtOAc extract of a Phaeoacremonium sp., an endophytic fungus obtained from the leaves of Senna spectabilis. The structures of these compounds were elucidated based on the analysis of spectroscopic data. Compounds 2 and 4 were active against the phytopathogenic fungi Cladosporium cladosporioides and C. sphaerospermum. This is the first report of metabolites produced by an Phaeoacremonium sp., associated with S. spectabilis.
Asunto(s)
Acetales/aislamiento & purificación , Acetales/farmacología , Antifúngicos/aislamiento & purificación , Antifúngicos/farmacología , Ascomicetos/química , Cladosporium/química , Cetonas/aislamiento & purificación , Cetonas/farmacología , Lactonas/aislamiento & purificación , Hojas de la Planta/química , Senna/química , Acetales/química , Antifúngicos/química , Cetonas/química , Lactonas/química , Lactonas/metabolismo , Lactonas/farmacología , Estructura MolecularRESUMEN
A sensitive and efficient colorimetric method was optimized for detection of esterase enzymes produced by endophytic fungi for development of High-Throughput Screening (HTS). The fungi were isolated and obtained previously from plant species of Cerrado and Atlantic Forest located in areas of environmental preservation in the State of Sao Paulo / Brazil, as part of the project "Chemical and biological prospecting endophytic fungi associated to plant species of Cerrado and Atlantic Forest". The compounds ethyl butyrate, ethyl acetate and methyl propionate were used as standards esters which were hydrolyzed by extracellular enzyme from endophytic fungi (EC. 3.1.1.1 -carboxylesterases) for production of carboxylic acids. Thus, the reduction of the pH increases the protonated indicator concentration (bromothymol blue), changing the color of the reaction medium (from blue to yellow), that can be observed and measured by spectrophotometry at 616 nm. The methodology with acid-base indicator was performed on 13 microorganisms, aiming Periconia atropurpurea asapotential source of esterase for biotransformation of short chain esters. The results also evidenced that this methodology showed to be efficient, fast, cheap, having low consumption of reagents and easy development, and can be applied to screen carboxylic-ester hydrolases in a large number of microorganisms.
Asunto(s)
Colorimetría/métodos , Endófitos/enzimología , Esterasas/análisis , Hongos/enzimología , Acetatos/metabolismo , Brasil , Butiratos/metabolismo , Hongos/aislamiento & purificación , Concentración de Iones de Hidrógeno , Indicadores y Reactivos , Plantas/microbiología , Propionatos/metabolismoRESUMEN
O presente trabalho tem o objetivo de avaliar os efeitos do pólen do milho transgênico, que expressa a proteína entomopatogênica Cry1Ab, sobre aspectos biológicos da traça da cera (Galleria mellonella) e com isso propor uma discussão sobre as possibilidades de afecção desse piralídeo à campo, debatendo possíveis efeitos ecológicos. Um ensaio biológico foi realizado, onde se ofertou às larvas pólen do milho transgênico, pólen do milho convencional e pólen comercial. A duração da fase larval foi afetada pela composição da dieta, sendo que as constituídas de pólen de milho convencional e transgênico apresentaram os resultados mais expressivos. A mortalidade foi superior nos indivíduos alimentados com a mistura de cera virgem e pólen transgênico, no entanto não diferiu dos demais alimentos, quando junto ao pólen transgênico, foi associado favo de Apis mellifera. A largura e comprimento das pupas provindas de lagartas alimentadas com cera virgem adicionada com pólen transgênico ou convencional foram significativamente inferiores quando comparados aos valores das mensurações realizadas nas pupas provindas de outras dietas. O pólen do milho, convencional ou transgênico, por si só é um alimento menos adequado ao desenvolvimento de G. mellonella, em relação a uma dieta composta por pólen de várias plantas.
This study aims to evaluate the effects of transgenic corn pollen, which expresses the Cry1Ab protein entomopathogenic on biological aspects the wax moth (Galleria mellonella) and thus propose a discussion on the possibilities for this condition pyralid the field, discussing possible ecological effects. For this we performed a bioassay, where it was offered to the larvae conventional and commercial Bt pollen, The duration of the larval stage of G. mellonella was affected by the supply of Mays pollen, conventional or transgenic, provided the biggest records. Mortality was higher in individuals fed with transgenic pollen and bee wax, but did not differ from other foods, when they were fed with transgenic pollen and honeycomb of Apis mellifera. The width and the length of larvae originated from larvae fed with beeswax added to conventional or transgenic pollen were lower than other treatments. The Mays pollen, conventional or transgenic alone is a less suitable food for the development of G. mellonella, in relation to a diet consisting of pollen from various plants.
Asunto(s)
Polen , Zea mays , Alimentos Modificados Genéticamente , Apicultura , LepidópterosRESUMEN
A sensitive and efficient colorimetric method was optimized for detection of esterase enzymes produced by endophytic fungi for development of High-Throughput Screening (HTS). The fungi were isolated and obtained previously from plant species of Cerrado and Atlantic Forest located in areas of environmental preservation in the State of Sao Paulo / Brazil, as part of the project "Chemical and biological prospecting endophytic fungi associated to plant species of Cerrado and Atlantic Forest". The compounds ethyl butyrate, ethyl acetate and methyl propionate were used as standards esters which were hydrolyzed by extracellular enzyme from endophytic fungi (EC. 3.1.1.1--carboxyl-esterases) for production of carboxylic acids. Thus, the reduction of the pH increases the protonated indicator concentration (bromothymol blue), changing the color of the reaction medium (from blue to yellow), that can be observed and measured by spectrophotometry at 616 nm. The methodology with acid-base indicator was performed on 13 microorganisms, aiming Periconia atropurpurea as a potential source of esterase for biotransformation of short chain esters. The results also evidenced that this methodology showed to be efficient, fast, cheap, having low consumption of reagents and easy development, and can be applied to screen carboxylic-ester hydrolases in a large number of microorganisms.
Asunto(s)
Colorimetría/métodos , Endófitos/enzimología , Esterasas/análisis , Hongos/enzimología , Acetatos/metabolismo , Brasil , Butiratos/metabolismo , Hongos/aislamiento & purificación , Concentración de Iones de Hidrógeno , Indicadores y Reactivos , Plantas/microbiología , Propionatos/metabolismoRESUMEN
Hydrolysis of whey lactose to glucose and galactose by immobilized galactosidase comes as an alternative to enlarge the possibilities of commercial use of this feedstock. To be applied at industrial scale, the process should be performed continuously .This work aimed to study the hydrolysis of whey lactose by an immobilized enzyme reactor. b-Galactosidase from Aspergillus oryzae was immobilized on silica and activity and stability were evaluated. The best immobilization results were attained by using glutaraldehyde as support's activator and enzyme stabilizer. The optimized enzyme proportion for immobilization was 15-20 mg g-1 of support. Treatments of whey were performed (microfiltration, thermal treatment and ultrafiltration), seeking the elimination of sludge, and the effects on operating the fixed bed reactor were evaluated. Ultrafiltration was the best treatment towards a proper substrate solution for feeding the reactor.
A hidrólise de lactose de soro de leite, resultando em glicose e galactose, apresenta-se como uma alternativa para ampliar as possibilidades de uso comercial deste insumo. Para ser aplicado em escala industrial, o processo deve ser operado de modo contínuo. Reporta-se o estudo de um sistema objetivando hidrólise de lactose de soro de leite através de um reator com enzima imobilizada. b-Galactosidase de Aspergillus oryzae foi imobilizada em sílica, sendo avaliadas a estabilidade e atividade. Os melhores resultados de imobilização foram obtidos usando glutaraldeído como ativante do suporte e estabilizador da enzima. A proporção otimizada entre enzima e suporte foi 15-20 mg.g-1. Foram estudadas formas de tratamento do soro (microfiltração, tratamento térmico e ultrafiltração), objetivando eliminação de material suspenso, e avaliando os efeitos na operação de reator de leito fixo. A ultrafiltração foi o melhor tratamento, na busca de uma solução de substrato apropriada para o reator contínuo.
RESUMEN
Urbanus acawoios (Lepidoptera: Hesperiidae) tem como principal hospedeiro a essência arbórea Clitoria fairchildiana (Leguminosae: Faboideae), utilizada em diversos estados brasileiros, principalmente, na arborizaçäo urbana. Nos últimos anos, foram registrados surtos anuais deste inseto, principalmente no estado do Rio de Janeiro, com desfolha intensa e conseqüente estresse fisiológico das árvores. Este trabalho teve como objetivo avaliar, em laboratório, o consumo foliar e aspectos biológicos de U. acawoios, alimentado com folíolos de C. fairchildiana em três diferentes estádios de maturidade: novos, intermediários e velhos. O consumo de lagartas de U. acawoios foi maior com folíolos novos e a duraçäo das fases de desenvolvimento, a longevidade e o ciclo de vida desse inseto foram afetados pelo tipo de folíolo de C. fairchildiana. A porcentagem de sobrevivência de U. acawoios foi maior para indivíduos alimentados com folíolos de C. fairchildiana de maturidade intermediária.
RESUMEN
Lipases are versatile enzymes regarding the range of reactions they catalyse and substrates on which they act. They are as well important as catalyst in organic synthesis. Their immobilization on appropriate supports confer them greater stability besides the possibility of operating in continuous reactors. In order to explore these abilities, the reactions involving hydrolysis of p-nitrophenyl acetate (PNPA) and transesterification of PNPA with n-butanol were chosen. Lipases from two different sources were assayed, namely: microbial (Candida rugosa, CRL, Sigma Type VII) and pancreatic (PPL, Sigma, Type II). Two immobilization methods were also used, namely: 1). adsorption, using as support the following silica derivatives (150-300 microm e 450micro): phenyl, epoxy, amino and without derivation, and 2). covalent binding, using glutaraldehyde as binding agent and silica amino as support. This later method led to better results. Hydrolytic activity was 6.1 U/g(support) for CRL and 0.97 U/g(support) for PPL, and of transesterification, 2,8 U/g(support) for CRL and 1,9 U/g(support) for PPL. Stability of the immobilized enzyme as a function of temperature was evaluated for CRL at 40 degrees C and 50 degrees C and for PPL at 32 degrees C and 40 degrees C. The assays were initially carried out batchwise, both for soluble and immobilized enzymes, aiming to the obtention of parameters for the continuous reactor. Lipases immobilized by covalent binding were used in the assays of operational stability in continuous reactors. For PPL in aqueous medium, at 32 degrees C, and CRL in organic medium at 40 degrees C, both operating continuously, no significant loss of activity was detected along the analysis period of 17 days. In the case of CRL in aqueous medium at 40 degrees C there was a loss of activity around 40% after 18 days. For PPL in organic medium at 40 degrees C the loss was 33% after 20 days. Comparing both sources with each other, very different results were obtained. Higher activity was found for CRL, both for hydrolysis and for transesterification reactions, with higher stability in organic medium. PPL showed lower activity as well as higher stability in aqueous medium. The immobilization method by covalent binding showed to be the most appropriate. Immobilized lipases are therefore relatively stable both in aqueous and organic medium.
Asunto(s)
Reactores Biológicos , Enzimas Inmovilizadas/metabolismo , Lipasa/metabolismo , Adsorción , Animales , Candida , Desecación , Estabilidad de Enzimas , Glutaral , Lipasa/química , Dióxido de Silicio , Porcinos , Temperatura , Factores de TiempoRESUMEN
The total and partially purified enzyme pectinmethylesterase from acerola fruit was covalently immobilized on porous silica particles. These efficiency values were 114% for the total PME and 351% for the partially purified PME. In both forms the immobilization resulted in compounds with high thermal stability.
Asunto(s)
Hidrolasas de Éster Carboxílico/química , Hidrolasas de Éster Carboxílico/metabolismo , Materiales Biocompatibles Revestidos/síntesis química , Malpighiaceae/enzimología , Dióxido de Silicio/química , Hidrolasas de Éster Carboxílico/aislamiento & purificación , Materiales Biocompatibles Revestidos/química , Activación Enzimática , Estabilidad de Enzimas , Enzimas Inmovilizadas/química , Calor , Concentración de Iones de Hidrógeno , Malpighiaceae/química , Membranas Artificiales , Porosidad , TemperaturaRESUMEN
No presente trabalho apresenta-se um método de cristalizaçäo da papaína oriunda do látex fresco de mamäo, o qual apresenta uma alta produtividade em relaçäo aos métodos previamente descritos. A metodologia aqui descrita näo envolve o uso de reagentes sulfídrilicos, a papaína foi obtida de forma praticamente pura, apresentando uma simples banda quando submetida a eletroforese, e com propriedades idênticas àquelas obtidas por outros métodos. A atividade específica foi determinada utilizando Z-gly-pNP e BAEF como substrato. A papaína obtida por essa metodologia, sem uso de substâncias tais como cisteína e ditiotreitol, apresenta-se na forma de um complexo com inibidores naturais, os quais podem ser removidos por diálise
Asunto(s)
Tecnología de Alimentos , Cristalización , Cisteína , Ditiotreitol , Electroforesis , PapaínaRESUMEN
Macroporous silica gel, prepared from sodium silicate and hydrochloric acid, one grade of diatomaceous earth (celite 545) and nonporous glass were analyzed in terms of pore size by the mercury intrusion pressure method. The alkylamine derivatives of the above materials were examined for their suitability as supports for enzyme immobilization, using the enzyme glucose oxidase. The effectiveness of the immobilized enzyme was compared in relation to the free enzyme and particle size of the carier. The immobilized enzyme exhibited a broader range of optimum pH and greater thermal stability, among some properties considered