Use of transgenic Aedes aegypti in Brazil: risk perception and assessment.

The OX513A strain of Aedes aegypti, which was developed by the British company Oxitec, expresses a self-limiting transgene that prevents larvae from developing to adulthood. In April 2014, the Brazilian National Technical Commission on Biosafety completed a risk assessment of OX513A and concluded that the strain did not present new biological risks to humans or the environment and could be released in Brazil. At that point, Brazil became the first country to approve the unconstrained release of a genetically modified mosquito. During the assessment, the commission produced a comprehensive list of - and systematically analysed - the perceived hazards. Such hazards included the potential survival to adulthood of immature stages carrying the transgene - should the transgene fail to be expressed or be turned off by exposure to sufficient environmental tetracycline. Other perceived hazards included the potential allergenicity and/or toxicity of the proteins expressed by the gene, the potential for gene flow or increased transmission of human pathogens and the occupation of vacant breeding sites by other vector species. The Zika epidemic both elevated the perceived importance of Ae. aegypti as a vector - among policy-makers and regulators as well as the general public - and increased concerns over the release of males of the OX513A strain. We have therefore reassessed the potential hazards. We found that release of the transgenic mosquitoes would still be both safe and of great potential value in the control of diseases spread by Ae. aegypti, such as chikungunya, dengue and Zika.

La souche OX513A d'Aedes aegypti, qui a été créée par la société britannique Oxitec, exprime un transgène autolimitant qui empêche les larves de se développer et de devenir adultes. En avril 2014, la Commission technique nationale de biosécurité du Brésil a procédé à une évaluation des risques liés à la souche OX513A et conclu qu'elle ne présentait pas de nouveaux risques biologiques pour les êtres humains ou l'environnement et pouvait être lâchée au Brésil. Le Brésil est donc devenu le premier pays à approuver le lâcher non contraint d'un moustique génétiquement modifié. Au cours de l'évaluation, la commission a établi une liste exhaustive des risques perçus, qu'elle a par ailleurs systématiquement analysés. Ces risques incluaient la survie potentielle à l'âge adulte des larves immatures porteuses du transgène ­ si le transgène ne s'exprime pas ou est désactivé par une exposition à la tétracycline suffisante dans l'environnement. Les autres risques perçus incluaient les potentielles propriétés allergisantes et/ou la toxicité des protéines exprimées par le gène, l'éventualité d'un flux de gènes ou d'une transmission accrue d'agents pathogènes pour l'homme et l'occupation de sites de reproduction vacants par d'autres espèces vectrices. L'épidémie d'infections à virus Zika a accentué l'importance accordée par les responsables politiques, les organismes de réglementation ainsi que le grand public à Ae. aegypti en tant que moustique vecteur, et a accru l'inquiétude relative au lâcher de mâles de la souche OX513A. Nous avons donc réévalué les risques potentiels. Nous estimons que le lâcher de moustiques transgéniques serait à la fois sans danger et extrêmement utile pour lutter contre les maladies transmises par Ae. aegypti, telles que le chikungunya, la dengue et le virus Zika.

La cepa OX513A de Aedes aegypti, que desarrolló la empresa británica Oxitec, expresa un transgén autolimitado que impide que las larvas se desarrollen hasta la edad adulta. En abril de 2014, la Comisión Nacional Técnica de Bioseguridad de Brasil realizó una evaluación de riesgos de OX513A y concluyó que la cepa no presentaba nuevos riesgos biológicos para los humanos o el medioambiente y que podría liberarse en Brasil. En ese momento, Brasil se convirtió en el primer país en aprobar la liberación ilimitada de un mosquito modificado genéticamente. A lo largo de la evaluación, la comisión redactó una lista completa, y analizada sistemáticamente, de las posibles contingencias. Entre dichos peligros se encontraba la posible supervivencia hasta la edad adulta de etapas inmaduras que portan el transgén, en caso de que éste no consiga expresarse o se inutilice debido a la exposición a la suficiente tetraciclina medioambiental. Otras posibles contingencias eran la alergia y/o toxicidad de las proteínas expresadas por el gen, la posibilidad de un flujo genético o el aumento de la transmisión de patógenos humanos y la ocupación de lugares de cría desocupados por parte de otras especies vectores. La epidemia por el virus de Zika aumentó la importancia de Ae. aegypti como vector, entre los responsables y reguladores políticos, así como entre el público general, y aumentó las preocupaciones acerca de la liberación de machos de la cepa OX513A. Por lo tanto, se han vuelto a evaluar los posibles riesgos. Se ha descubierto que la liberación de mosquitos transgénicos sería segura y tendría un gran valor potencial en el control de la propagación de enfermedades por Ae. aegypti, como la fiebre chikungunya, el dengue y la enfermedad por el virus de Zika.

The physical, chemical and functional characterization of starches from Andean tubers: oca (Oxalis tuberosa Molina), olluco (Ullucus tuberosus Caldas) and mashua (Tropaeolum tuberosum Ruiz & Pavón)

The physical, chemical, and functional properties of starches isolated from the Andean tubers oca (Oxalis tuberosa M.), olluco (Ullucus tuberosus C.) and mashua (Tropaeolum tuberosum R. & P.) were studied. The tubers were obtained from a local grocery. The morphology of the starch granules (size and shape) was studied with scanning electron microscopy (SEM), which revealed ellipsoid, oval, conical, pear-shaped and prismatic forms: ellipsoids and oval granules with lengths up to 54.30 µm in oca; with lengths up to 32.09 µm for olluco starch granules; and with predominantly truncated spherical or oval forms and smaller dimensions (up to 16.29 um) for mashua starch granules. Amylose contents were similar among the samples: 27.60% (oca), 26.49% (olluco) and 27.44% (mashua). Olluco starch had less swelling power, forming opaque, less firm gels. All three starch gels showed the same stability on refrigeration and presented high syneresis under freezing temperatures, with a variation of 40.28 to 74.42% for olluco starch. The starches cooked easily, with high peak viscosity. The low gelatinization temperatures and high stability during cooling make these starches suitable feedstock for use in formulations that require milder processing temperatures and dispense freezing storage.

As propriedades físicas, químicas e funcionais de amidos isolados das tuberosas andinas, oca (Oxalis tuberosa M.), olluco (Ullucus tuberosus C.) e mashua (Tropaeolum tuberosum R. & P.), obtidas no comércio local, foram estudadas. A morfologia dos grânulos de amido foi avaliada por microscopia eletrônica de varredura (SEM) revelando formas elipsoidais, ovais, cônicas, periformes e prismáticas: grânulos elipsoides e ovais com dimensões de até 54,30 µm de comprimento para a oca, de até 32,09 µm para o amido de olluco, e com formas predominantemente esféricas ou ovais truncadas, de menores dimensões de até 16,29 µm para grânulos de amido de mashua. Os conteúdos de amilose foram similares entre as amostras: 27,60% (oca), 26,49% (olluco) e 27,44% (mashua). O amido de olluco teve menor poder de intumescimento, formando géis opacos e menos resistentes. Os géis dos três amidos mostraram a mesma estabilidade sob refrigeração e apresentaram alta sinérese após congelamento, com variação de 40,28 a 74,42% para amido de olluco. Os amidos tiveram cocção rápida com alto pico de viscosidade. A baixa temperatura de gelatinização e alta estabilidade durante a refrigeração fazem destes amidos matérias-primas adequadas para formulações que requeiram temperaturas brandas de processamento e que dispensem conservação por congelamento.

Effects on starch and amylolytic enzymes during Lepidium meyenii Walpers root storage.

The high water content in maca (Lepidium meyenii W.) roots combined with the damage produced during or after harvest makes them vulnerable to attack by enzymes and microorganisms. Although starch degradation has been extensively studied, in maca roots there is a paucity of research regarding the starch reserves. In this paper, parameters of starch degradation are shown to be related to the action of amylolytic enzymes during storage at room temperature. Over the course of three weeks, the starch and protein content, soluble sugar, total amylolytic activity, and α- and ß-amylase activity were measured. In addition, the integrity of starch granules was observed by scanning electron microscopy. Despite the evidence of dehydration, there were no significant differences (p ≤ 0.5) in the total starch content or in the activities of α- and ß-amylase. After the third week the roots remained suitable for consumption. The results indicate a postharvest latency that can lead to sprout or to senescence, depending on the environmental conditions.

Molecular and structural characterization of a trypsin highly expressed in larval stage of Zabrotes subfasciatus.

The Mexican bean weevil, Zabrotes subfasciatus, feeds on several seeds such as Vigna unguiculata, Phaseolus vulgaris, and Pisum sativum, causing severe crop losses. This ability to obtain essential compounds from different diets could possibly be explained due to a wide variability of digestive proteinases present in the weevil's midgut. These may improve digestion of many different dietary proteins. Coleopteran serine-like proteinases have not been thoroughly characterized at the molecular level. In this report, a full-length cDNA encoding a trypsin-like protein, named ZsTRYP, was isolated from Z. subfasciatus larvae using RT-PCR, 5' and 3' RACE techniques. The quantitative real-time PCR analysis strongly correlated the Zstryp transcript accumulation to the major feeding developmental larval stage. Zstryp cDNA was subcloned into pET101 vector and expressed in a Escherichia coli BL21(DE3) strain. Nickel-nitrilotriacetic acid (Ni-NTA) affinity chromatography was used to purify a 29.0-kDa recombinant enzyme. The purified ZsTRYP was then assayed with several synthetic peptide substrates and also challenged with different inhibitors. The biochemical data allowed us to classify ZsTRYP as a trypsin. Moreover, homology modeling analysis indicated a typical trypsin structural core and a conserved catalytic triad (His(41), Asp(86), and Ser(182)).

Preliminary approach to detect amylolytic and pectinolytic activities from maca (Lepidium meyenii Walp)

O objetivo do presente estudo foi determinar valores ideais de pH e temperatura para avaliar as atividades amilolítica (AM), pectinesterásica (PE) e poligalacturonásica (PG) em raízes de maca (Lepidium meyenii Walp.). Foi utilizado o modelo de superfície de resposta para atingir valores confiáveis de atividades enzimáticas em extratos brutos. Os valores máximos de atividade AM ocorreram em pH 6,1 a 33,6 °C, muito próximos do ponto central dos experimentos. Para as atividades de PE e PG, o valores ótimos foram atingidos em pHs 6,6 e 5,4, a 49,4 e 46 °C, respectivamente.

Alimentos sem glúten no controle da doença celíaca / Gluten free foods for control of celiac disease

A doença celíaca é uma enfermidade digestiva causada pelo efeito tóxico do glúten, o qual danifica o trato intestinal e interfere na absorção de nutrientes. Os sintomas podem variar desde uma desnutrição até o surgimento de linfomas. O tratamento é basicamente dietético, devendo-se excluir o glúten da dieta, evitando-se a ingestão de trigo, cevada, centeio, aveia e de grãos híbridos desses cereais, como o Triticale sp. Em relação à aveia, estudos mostram que alguns pacientes podem tolerar seu consumo em função da estrutura de sua fração protética e da baixa quantidade de aveninas presente no grão. Uma grande atenção deve ser dada aos alimentos e produtos farmacêuticos que utilizam amido de trigo como ingrediente em suas formulações...

As múltiplas funções das lectinas vegetais / The multiple functions of plant lectins

O trabalho aborda aspectos bioquímicos e funcionais das lectinas vegetais com ênfase na caracterização molecular e na aplicação biotecnológica dessas proteínas, através do conhecimento da especificidade das interações proteína-carboidrato. O conhecimento atual ajuda a esclarecer o papel fisiológico das lectinas, os mecanismos internos de proteção da planta e a ação tóxica sobre predadores, bem como permite o desenvolvimento de técnicas de diagnóstico e possibilita o delineamento de novas formas de expressão em plantas geneticamente modificadas.