The art of vector engineering: towards the construction of next-generation genetic tools.

When recombinant DNA technology was developed more than 40 years ago, no one could have imagined the impact it would have on both society and the scientific community. In the field of genetic engineering, the most important tool developed was the plasmid vector. This technology has been continuously expanding and undergoing adaptations. Here, we provide a detailed view following the evolution of vectors built throughout the years destined to study microorganisms and their peculiarities, including those whose genomes can only be revealed through metagenomics. We remark how synthetic biology became a turning point in designing these genetic tools to create meaningful innovations. We have placed special focus on the tools for engineering bacteria and fungi (both yeast and filamentous fungi) and those available to construct metagenomic libraries. Based on this overview, future goals would include the development of modular vectors bearing standardized parts and orthogonally designed circuits, a task not fully addressed thus far. Finally, we present some challenges that should be overcome to enable the next generation of vector design and ways to address it.

A future scenario of the global regulatory landscape regarding genome-edited crops.

The global agricultural landscape regarding the commercial cultivation of genetically modified (GM) crops is mosaic. Meanwhile, a new plant breeding technique, genome editing is expected to make genetic engineering-mediated crop breeding more socially acceptable because it can be used to develop crop varieties without introducing transgenes, which have hampered the regulatory review and public acceptance of GM crops. The present study revealed that product- and process-based concepts have been implemented to regulate GM crops in 30 countries. Moreover, this study analyzed the regulatory responses to genome-edited crops in the USA, Argentina, Sweden and New Zealand. The findings suggested that countries will likely be divided in their policies on genome-edited crops: Some will deregulate transgene-free crops, while others will regulate all types of crops that have been modified by genome editing. These implications are discussed from the viewpoint of public acceptance.

Transumanismo e o futuro (pós-)humano / Transhumanism and the (post)human future

O transumanismo é uma controversa perspectiva de investimento na transformação da condição humana. Visando ao melhoramento biotecnológico da natureza humana, ele protagoniza o debate acerca do futuro (pós-)humano. Na base da concepção transumanista está o investimento na biotecnociência como um modo de Iluminismo humanista de raízes biológicas. O objetivo do artigo é analisar o debate sobre o futuro da humanidade. Para tanto, apresentamos a perspectiva transumanista, ressaltando definições, características, valores e principais argumentos, analisando o conceito de natureza humana, pois ele é fundamental na polarizada discussão travada entre os transumanistas e bioconservadores. Nossas principais conclusões apontam para a impertinência dessa polarização, bem como do uso do conceito de natureza humana e pós-humano para esclarecer o tema do melhoramento humano. Assim, cumpre despolarizar o debate e apostar otimista e prudentemente no futuro biotecnológico...

Transhumanism is a controversial perspective of the investment in transformation of the human condition. Targeting at biotechnological human nature enhancement, it emerges as one of the protagonists in the debate about the (post)human future. At the base transhumanist conception is the investment on the biotechnoscience as a humanistic iluminism of biological roots. This paper aims to analyze the debate about the future of humanity. To this end, we present the transhumanist perspective, highlighting definitions, characteristics, values, and main arguments, analyzing the concept of human nature, for it is fundamental in the polarized discussion between the transhumanists and bioconservatives. Our main conclusions indicate the impertinence of the polarization, as well as the use of the concept of human nature and post-human to clarify the theme of human enhancement. Thus, we must depolarize the debate and bet optimistically and prudently in the biotechnological future...

Genetic engineering in Cowpea (Vigna unguiculata): history, status and prospects.

In the last three decades, a number of attempts have been made to develop reproducible protocols for generating transgenic cowpea that permit the expression of genes of agronomic importance. Pioneer works focused on the development of such systems vis-à-vis an in vitro culture system that would guarantee de novo regeneration of transgenic cowpea arising from cells amenable to one form of gene delivery system or another, but any such system has eluded researchers over the years. Despite this apparent failure, significant progress has been made in generating transgenic cowpea, bringing researchers much nearer to their goal than thirty years ago. Now, various researchers have successfully established transgenic procedures for cowpea with evidence of inherent transgenes of interest, effected by progenies in a Mendelian fashion. New opportunities have thus emerged to optimize existing protocols and devise new strategies to ensure the development of transgenic cowpea with desirable agronomic traits. This review chronicles the important milestones in the last thirty years that have marked the evolution of genetic engineering of cowpea. It also highlights the progress made and describes new strategies that have arisen, culminating in the current status of transgenic technologies for cowpea.

Two decades of plant-based candidate vaccines: a review of the chimeric protein approaches.

Genetic engineering revolutionized the concept of traditional vaccines since subunit vaccines became reality. Additionally, over the past two decades plant-derived antigens have been studied as potential vaccines with several advantages, including low cost and convenient administration. More specifically, genetic fusions allowed the expression of fusion proteins carrying two or more components with the aim to elicit immune responses against different targets, including antigens from distinct pathogens or strains. This review aims to provide an update in the field of the production of plant-based vaccine, focusing on those approaches based on the production of chimeric proteins comprising antigens from human pathogens, emphasizing the case of cholera toxin/E. coli enterotoxin fusions, chimeric viruses like particles approaches as well as the possible use of adjuvant-producing plants as expression hosts. Challenges for the near future in this field are also discussed.

Engineering the future. Development of transgenic plants with enhanced tolerance to adverse environments.

Environmental stresses - especially drought and salinity - and iron limitation are the primary causes of crop yield losses. Therefore, improvement of plant stress tolerance has paramount relevance for agriculture, and vigorous efforts are underway to design stress-tolerant crops. Three aspects of this ongoing research are reviewed here. First, attempts have been made to strengthen endogenous plant defences, which are characterised by intertwined, hierarchical gene networks involved in stress perception, signalling, regulation and expression of effector proteins, enzymes and metabolites. The multigenic nature of this response requires detailed knowledge of the many actors and interactions involved in order to identify proper intervention points, followed by significant engineering of the prospective genes to prevent undesired side-effects. A second important aspect refers to the effect of concurrent stresses as plants normally meet in the field (e.g., heat and drought). Recent findings indicate that plant responses to combined environmental hardships are somehow unique and cannot be predicted from the addition of the individual stresses, underscoring the importance of programming research within this conceptual framework. Finally, the photosynthetic microorganisms from which plants evolved (i.e., algae and cyanobacteria) deploy a totally different strategy to acquire stress tolerance, based on the substitution of stress-vulnerable targets by resistant isofunctional proteins that could take over the lost functions under adverse conditions. Reintroduction of these ancient traits in model and crop plants has resulted in increased tolerance to environmental hardships and iron starvation, opening a new field of opportunities to increase the endurance of crops growing under suboptimal conditions.

Current status of transgenic animal research for human health applications

Background: The current status of genetic engineering animals for biomedical and human health applications, including improving the supply of animal-based food products, was reviewed. Although transgenic animals have been available for almost 30 years only one product, a drug derived from transgenic goats' milk, has been approved for use anywhere in the world. While a number of technical issues limited efficiency initially, products coming to market were hindered by the lack of a regulatory framework and compounded by opposition from anti-biotechnology groups. Review: As presented in the review, the production of genetically engineered livestock has progressed from the initial technology of pronuclear microinjection through to the wide-spread use today of somatic cell nuclear transfer-based cloning technology following the transfection of cells in culture with methods such as lipofection or electroporation. There also was significant progress in the development of systems based upon lentivirus or adeno-associated virus-based vectors. More recently, advances occurred based on transposon-mediated transgenesis. In conjunction with advances in methods to genetically engineer livestock, there are also advances, such as the use of zinc-finger nucleases and transient depletion of endogenous non-homologous recombination systems, to increase the efficiency of homologous recombination-based gene targeting. Applications range from the production of pharmaceutical proteins, silk for use in sutures and scaffolds for cellular regeneration, and xenotransplantation through to the development of transgenic animals that improve animal production and the nutritional value of animal-based food products. Both of these agricultural applications are important for maintaining the global production of sufficient meat-based products in an economically and environmentally sustainable manner in the face of a dramatically increasing human population. Conclusion: Advances in the production of genetically engineered animals and identification of useful applications have significantly improved and have set the stage for the adoption of transgenic animals. Brazil, because of recent technological developments and the adoption of regulatory guidelines is now in a strong position to benefit from genetically engineered animals and to contribute to the leadership in the adoption of transgenic animals for applications to improve human and animal health and well-being.

Biosafety education relevant to genetically engineered crops for academic and non-academic stakeholders in East Africa

Development and deployment of genetically engineered crops requires effective environmental and food safety assessment capacity. In-country expertise is needed to make locally appropriate decisions. In April 2007, biosafety and biotechnology scientists, regulators, educators, and communicators from Kenya, Tanzania, and Uganda, met to examine the status and needs of biosafety training and educational programs in East Africa. Workshop participants emphasized the importance of developing biosafety capacity within their countries and regionally. Key recommendations included identification of key biosafety curricular components for university students; collaboration among institutions and countries; development of informational materials for non-academic stakeholders and media; and organization of study tours for decision makers. It was emphasized that biosafety knowledge is important for all aspects of environmental health, food safety, and human and animal hygiene. Thus, development of biosafety expertise, policies and procedures can be a stepping stone to facilitate improved biosafety for all aspects of society and the environment.

Melon fruits: genetic diversity, physiology, and biotechnology features.

Among Cucurbitaceae, Cucumis melo is one of the most important cultivated cucurbits. They are grown primarily for their fruit, which generally have a sweet aromatic flavor, with great diversity and size (50 g to 15 kg), flesh color (orange, green, white, and pink), rind color (green, yellow, white, orange, red, and gray), form (round, flat, and elongated), and dimension (4 to 200 cm). C. melo can be broken down into seven distinct types based on the previously discussed variations in the species. The melon fruits can be either climacteric or nonclimacteric, and as such, fruit can adhere to the stem or have an abscission layer where they will fall from the plant naturally at maturity. Traditional plant breeding of melons has been done for 100 years wherein plants were primarily developed as open-pollinated cultivars. More recently, in the past 30 years, melon improvement has been done by more traditional hybridization techniques. An improvement in germplasm is relatively slow and is limited by a restricted gene pool. Strong sexual incompatibility at the interspecific and intergeneric levels has restricted rapid development of new cultivars with high levels of disease resistance, insect resistance, flavor, and sweetness. In order to increase the rate and diversity of new traits in melon it would be advantageous to introduce new genes needed to enhance both melon productivity and melon fruit quality. This requires plant tissue and plant transformation techniques to introduce new or foreign genes into C. melo germplasm. In order to achieve a successful commercial application from biotechnology, a competent plant regeneration system of in vitro cultures for melon is required. More than 40 in vitro melon regeneration programs have been reported; however, regeneration of the various melon types has been highly variable and in some cases impossible. The reasons for this are still unknown, but this plays a heavy negative role on trying to use plant transformation technology to improve melon germplasm. In vitro manipulation of melon is difficult; genotypic responses to the culture method (i.e., organogenesis, somatic embryogenesis, etc.) as well as conditions for environmental and hormonal requirements for plant growth and regeneration continue to be poorly understood for developing simple in vitro procedures to culture and transform all C. melo genotypes. In many cases, this has to be done on an individual line basis. The present paper describes the various research findings related to successful approaches to plant regeneration and transgenic transformation of C. melo. It also describes potential improvement of melon to improve fruit quality characteristics and postharvest handling. Despite more than 140 transgenic melon field trials in the United States in 1996, there are still no commercial transgenic melon cultivars on the market. This may be a combination of technical or performance factors, intellectual property rights concerns, and, most likely, a lack of public acceptance. Regardless, the future for improvement of melon germplasm is bright when considering the knowledge base for both techniques and gene pools potentially useable for melon improvement.

Genetic engineering and functional foods / Engenharia genética e alimentos funcionais

Functional foods are the food-industry response to the continuous ly increasing request of consumers for foods that are both attractive and healthy. The main targets of functional foods are intestinal health, immune system activity, mental performance, caries, menopause symptoms, cancer, cardiovascular disease, diabetes, osteoporosis and child skeletal development. Most of the functional foods designed so far are derived from traditional foods by adding so-called functional ingredients, by modifying the technological process during industrial food preparation or by modifying the composition of the raw material used for food production. However, gene technology is thought to be a powerful technique to improve the nutritional quality of food raw materials. The modification of product quality characteristics using gene technology depends on a well-establishe dunder standing of the pathways for biosynthesis of plant products, a rapidly expanding knowledge about the genetic control of these pathways, and an increasing availability of cloned genes for key enzymatic steps. Quality-improved crops derived from genetic engineering are expected to reach the market in the near future. Crops with an improved protein quality, with an improved nutritional quality of the plant oil, crops rich in vitamins, minerals, antioxidants or low in undesired compounds as well as crops with an altered secondary metabolite production or altered carbohydrate composition have been developed by genetic engineering. These examples give an idea of the genetic engineering potential to produce health-promoting foods

Los alimentos funcionales son la respuesta de la industria de alimentos a la creciente demanda de los consumidores por alimentos que sean al mismo tiempo atrayentes y saludables. Los principales objetivos de los alimentos funcionales son la salud intestinal, del sistema inmunológico,el desempeño mental, las caries, los síntomas dela menopausia, cáncer, enfermidades cardiovasculares, diabetes, osteoporosis y desenvolvimiento óseo en niños. La mayoría de los alimentos funcionales desarrollados hasta el momento son derivados de los alimentos tradicionales a los cuales se les adicionan los ingredientes funcionales, se les modifica el proceso tecnológico de industrialización o se les altera la composición de materias primas utilizadas en su producción. Sin embargo, se tiene por cierto que la tecnología genética es un instrumento poderoso para mejorar la calidad nutricional de las materias primas alimenticias. La modificación de las características de calidad del producto utilizando tecnología genética depende de un conocimiento asentado de las vías metabólicas de síntesis de productos vegetales, un conocimiento en rápida expansión sobre el control genético de tales vías y una creciente disponibilidad de genes clonados para la expresión de enzimas claves de algunos passos de esas vías. Se espera que cultivos con calidad mejorada originarios de ingeniería genéticalleguen al mercado en un futuro próximo.Cultivos con mejor calidad de proteínas y lípidos, con mayor concentración de vitaminas, minerales y antioxidantes, con bajos tenores decompuestos indeseables y también cultivos com metabolitos secundarios modificados o composición alterada de carbohidratos son ejemplos de logros ya alcanzados por la ingeniería genética. Los ejemplos mencionados permiten visualizar el potencial de la ingeniería genética para la producción de alimentos promotores de la salud

Os alimentos funcionais são a resposta da indústria alimentícia à sempre crescente demanda dos consumidores por alimentos ao mesmo tempo atraentes e saudáveis. Os principais alvos dos alimentos funcionais são a saúde intestinal, a atividade do sistema imune, o desempenho mental, cáries, sintomas da menopausa, câncer, doenças cardiovasculares, diabetes, osteoporose e desenvolvimento ósseo de crianças. A maioria dos alimentos funcionais desenvolvidos, até o momento, são derivados de alimentos tradicionais pela adição dos ditos ingredientes funcionais, modificação dos processos tecnológicos durante o preparo industrial dos alimentos ou alteração da composição das matérias-primas usadas na produção dos alimentos. Contudo, acredita-se que a tecnologia genética seja um poderoso instrumento para melhorar a qualidade nutricional das matérias-primas alimentícias. A modificação das características de qualidade do produto usando a tecnologia genética depende de um conhecimento bem embasado sobre as rotas metabólicas de síntese de produtos vegetais, um conhecimento em rápida expansão sobre o controle genético de tais rotas metabólicas, e uma crescente disponibilidade de genes clonados para expressão de enzimas-chave de alguns passos destas rotas. Espera-se que culturas com qualidade melhorada derivadas da engenharia genética cheguem ao mercado num futuro próximo. Culturas com qualidade proteica melhorada, com melhor qualidade nutricional do óleo vegetal derivado, culturas ricas em vitaminas, minerais, antioxidantes ou com baixos teores de compostos indesejáveis, bem como culturas com produção de metabólitos secundários alterados ou composição alterada de carboidratos já foram desenvolvidas pela engenharia genética. Estes exemplos dão uma ideia do potencial da engenharia genética para produzir alimentos promotores de saúde

Células-Tronco - conceitos gerais e definições / Stem cells - general concepts and definitions

Uma nova era na biologia das células-tronco se iniciou em 1998 com a derivação de células a partir do blastocisto humano e tecido fetal, com habilidade única de se diferenciar em células de todos os tecidos do corpo. Desde então, várias equipes de pesquisadores têm demonstrado algumas das características moleculares e desenvolvido métodos para cultura destas células. A célula-tronco é um tipo especial de célula que tem capacidade única de se automultiplicar ou de dar origem a tipos celulares especializados. Embora a maioria das células do corpo, como células cardíacas ou células da derme, sejam diferenciadas para exercer uma função específica, a célula-tronco é indiferenciada e assim permanece até que receba um sinal para se desenvolver em algum tipo celular. Sua capacidade proliferativa combinada a sua habilidade de se especializar fazem delas células únicas

Bioetica de la manipulacion del hombre / Bioethics of manipulation of men

Analizando los diferentes empleos que se hacen del término manipulación, y la descripción y clasificación que del mismo hace la literatura científica, se entra a considerar la manipulación personal como manipulación biológica en el campo específico de la ingeniería genética (diferencia entre manipulación e ingeniería genética, objeto de esta manipulación, finalidades) y las diferentes manipulaciones a las que está sometido el ser humano: en el nivel biológico (manipulación del cerebro, trasplante de órganos), nivel quirúrgico (trasplante de ovarios, fecundación in vitro) y en el nivel de los genes (elección del sexo de los hijos, terapia de los genes, reproducción asexual y eufenética). Se finaliza con algunas pautas bioéticas para abordar el problema de la manipulación (manipulación y ciencia, manipulación y Bioética, el valor ético de la persona como dimensión crítica de toda manipulación y elpapel del bioeticista y el futuro del hombre).

Antibody engineering at the millennium.

It has been almost 100 years since von Behring and Kitasato received the first Nobel prize for the discovery of passive immunotherapy and nearly 25 years since Köhler and Milstein first reported hybridoma technology. In the 15 years since Mullis and co-workers described PCR, a number of discoveries and technologies have converged to produce a renaissance in antibody therapeutics. Our vision of antibodies as tools for research--useful for the prevention, detection and treatment of disease--has been revolutionized by these recent advances. This review specifically focuses on what is now called antibody engineering and includes chimeric and humanized antibodies, immunoglobulin fragments, antibody libraries, antibody fusion proteins and transgenic organisms as bioreactors. As a consequence of refinements in antibody technology, the field of genetically engineered immunoglobulins has matured into an elegant and important drug and reagent development platform.