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Sample records for modified crops resistant

  1. Why genetically modified crops?

    PubMed

    Jones, Jonathan D G

    2011-05-13

    This paper is intended to convey the message of the talk I gave at the Theo Murphy meeting at the Kavli Centre in July 2010. It, like the talk, is polemical, and conveys the exasperation felt by a practitioner of genetically modified (GM) plant science at its widespread misrepresentation. I argue that sustainable intensification of agriculture, using GM as well as other technologies, reduces its environmental impact by reducing pesticide applications and conserving soil carbon by enabling low till methods. Current technologies (primarily insect resistance and herbicide tolerance) have been beneficial. Moreover, the near-term pipeline of new GM methods and traits to enhance our diet, increase crop yields and reduce losses to disease is substantial. It would be perverse to spurn this approach at a time when we need every tool in the toolbox to ensure adequate food production in the short, medium and long term.

  2. Biotechnology: herbicide-resistant crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transgenic, herbicide-resistant (HR) crops are planted on about 80% of the land covered by transgenic crops. More than 90% of HR crios are glyphosate-resistant (GR) crops, the others being resistant to glufosinate. The wide-scale adoption of HR crops, largely for economic reasons, has been the mos...

  3. Promise and issues of genetically modified crops.

    PubMed

    Chen, Hao; Lin, Yongjun

    2013-05-01

    The growing area of genetically modified (GM) crops has substantially expanded since they were first commercialized in 1996. Correspondingly, the adoption of GM crops has brought huge economic and environmental benefits. All these achievements have been primarily supported by two simple traits of herbicide tolerance and insect resistance in the past 17 years. However, this situation will change soon. Recently, the advance of new products, technologies and safety assessment approaches has provided new opportunities for development of GM crops. In this review, we focus on the developmental trend in various aspects of GM crops including new products, technical innovation and risk assessment approaches, as well as potential challenges that GM crops are currently encountering.

  4. The benefits of herbicide-resistant crops.

    PubMed

    Green, Jerry M

    2012-10-01

    Since 1996, genetically modified herbicide-resistant crops, primarily glyphosate-resistant soybean, corn, cotton and canola, have helped to revolutionize weed management and have become an important tool in crop production practices. Glyphosate-resistant crops have enabled the implementation of weed management practices that have improved yield and profitability while better protecting the environment. Growers have recognized their benefits and have made glyphosate-resistant crops the most rapidly adopted technology in the history of agriculture. Weed management systems with glyphosate-resistant crops have often relied on glyphosate alone, have been easy to use and have been effective, economical and more environmentally friendly than the systems they have replaced. Glyphosate has worked extremely well in controlling weeds in glyphosate-resistant crops for more than a decade, but some key weeds have evolved resistance, and using glyphosate alone has proved unsustainable. Now, growers need to renew their weed management practices and use glyphosate with other cultural, mechanical and herbicide options in integrated systems. New multiple-herbicide-resistant crops with resistance to glyphosate and other herbicides will expand the utility of existing herbicide technologies and will be an important component of future weed management systems that help to sustain the current benefits of high-efficiency and high-production agriculture.

  5. Metabolomics of genetically modified crops.

    PubMed

    Simó, Carolina; Ibáñez, Clara; Valdés, Alberto; Cifuentes, Alejandro; García-Cañas, Virginia

    2014-10-20

    Metabolomic-based approaches are increasingly applied to analyse genetically modified organisms (GMOs) making it possible to obtain broader and deeper information on the composition of GMOs compared to that obtained from traditional analytical approaches. The combination in metabolomics of advanced analytical methods and bioinformatics tools provides wide chemical compositional data that contributes to corroborate (or not) the substantial equivalence and occurrence of unintended changes resulting from genetic transformation. This review provides insight into recent progress in metabolomics studies on transgenic crops focusing mainly in papers published in the last decade.

  6. Metabolomics of Genetically Modified Crops

    PubMed Central

    Simó, Carolina; Ibáñez, Clara; Valdés, Alberto; Cifuentes, Alejandro; García-Cañas, Virginia

    2014-01-01

    Metabolomic-based approaches are increasingly applied to analyse genetically modified organisms (GMOs) making it possible to obtain broader and deeper information on the composition of GMOs compared to that obtained from traditional analytical approaches. The combination in metabolomics of advanced analytical methods and bioinformatics tools provides wide chemical compositional data that contributes to corroborate (or not) the substantial equivalence and occurrence of unintended changes resulting from genetic transformation. This review provides insight into recent progress in metabolomics studies on transgenic crops focusing mainly in papers published in the last decade. PMID:25334064

  7. Genetically modified crops and food security.

    PubMed

    Qaim, Matin; Kouser, Shahzad

    2013-01-01

    The role of genetically modified (GM) crops for food security is the subject of public controversy. GM crops could contribute to food production increases and higher food availability. There may also be impacts on food quality and nutrient composition. Finally, growing GM crops may influence farmers' income and thus their economic access to food. Smallholder farmers make up a large proportion of the undernourished people worldwide. Our study focuses on this latter aspect and provides the first ex post analysis of food security impacts of GM crops at the micro level. We use comprehensive panel data collected over several years from farm households in India, where insect-resistant GM cotton has been widely adopted. Controlling for other factors, the adoption of GM cotton has significantly improved calorie consumption and dietary quality, resulting from increased family incomes. This technology has reduced food insecurity by 15-20% among cotton-producing households. GM crops alone will not solve the hunger problem, but they can be an important component in a broader food security strategy.

  8. Transgenic Crops for Herbicide Resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since their introduction in 1995, crops made resistant to the broad-spectrum herbicides glyphosate and glufosinate with transgenes are widely available and used in much of the world. As of 2008, over 80% of the transgenic crops grown world-wide have this transgenic trait. This technology has had m...

  9. Potential adverse health effects of genetically modified crops.

    PubMed

    Bakshi, Anita

    2003-01-01

    Genetically modified crops have the potential to eliminate hunger and starvation in millions of people, especially in developing countries because the genetic modification can produce large amounts of foods that are more nutritious. Large quantities are produced because genetically modified crops are more resistant to pests and drought. They also contain greater amounts of nutrients, such as proteins and vitamins. However, there are concerns about the safety of genetically modified crops. The concerns are that they may contain allergenic substances due to introduction of new genes into crops. Another concern is that genetic engineering often involves the use of antibiotic-resistance genes as "selectable markers" and this could lead to production of antibiotic-resistant bacterial strains that are resistant to available antibiotics. This would create a serious public health problem. The genetically modified crops might contain other toxic substances (such as enhanced amounts of heavy metals) and the crops might not be "substantially equivalent" in genome, proteome, and metabolome compared with unmodified crops. Another concern is that genetically modified crops may be less nutritious; for example, they might contain lower amounts of phytoestrogens, which protect against heart disease and cancer. The review of available literature indicates that the genetically modified crops available in the market that are intended for human consumption are generally safe; their consumption is not associated with serious health problems. However, because of potential for exposure of a large segment of human population to genetically modified foods, more research is needed to ensure that the genetically modified foods are safe for human consumption.

  10. Modifying agricultural crops for improved nutrition.

    PubMed

    McGloughlin, Martina Newell

    2010-11-30

    The first generation of biotechnology products commercialized were crops focusing largely on input agronomic traits whose value was often opaque to consumers. The coming generations of crop plants can be grouped into four broad areas each presenting what, on the surface, may appear as unique challenges and opportunities. The present and future focus is on continuing improvement of agronomic traits such as yield and abiotic stress resistance in addition to the biotic stress tolerance of the present generation; crop plants as biomass feedstocks for biofuels and "bio-synthetics"; value-added output traits such as improved nutrition and food functionality; and plants as production factories for therapeutics and industrial products. From a consumer perspective, the focus on value-added traits, especially improved nutrition, is undoubtedly one of the areas of greatest interest. From a basic nutrition perspective, there is a clear dichotomy in demonstrated need between different regions and socioeconomic groups, the starkest being inappropriate consumption in the developed world and under-nourishment in Less Developed Countries (LDCs). Dramatic increases in the occurrence of obesity and related ailments in affluent regions are in sharp contrast to chronic malnutrition in many LDCs. Both problems require a modified food supply, and the tools of biotechnology have a part to play. Developing plants with improved traits involves overcoming a variety of technical, regulatory and indeed perception hurdles inherent in perceived and real challenges of complex traits modifications. Continuing improvements in molecular and genomic technologies are contributing to the acceleration of product development to produce plants with the appropriate quality traits for the different regions and needs. Crops with improved traits in the pipeline, the evolving technologies and the opportunities and challenges that lie ahead are covered.

  11. Elevating crop disease resistance with cloned genes

    PubMed Central

    Jones, Jonathan D. G.; Witek, Kamil; Verweij, Walter; Jupe, Florian; Cooke, David; Dorling, Stephen; Tomlinson, Laurence; Smoker, Matthew; Perkins, Sara; Foster, Simon

    2014-01-01

    Essentially all plant species exhibit heritable genetic variation for resistance to a variety of plant diseases caused by fungi, bacteria, oomycetes or viruses. Disease losses in crop monocultures are already significant, and would be greater but for applications of disease-controlling agrichemicals. For sustainable intensification of crop production, we argue that disease control should as far as possible be achieved using genetics rather than using costly recurrent chemical sprays. The latter imply CO2 emissions from diesel fuel and potential soil compaction from tractor journeys. Great progress has been made in the past 25 years in our understanding of the molecular basis of plant disease resistance mechanisms, and of how pathogens circumvent them. These insights can inform more sophisticated approaches to elevating disease resistance in crops that help us tip the evolutionary balance in favour of the crop and away from the pathogen. We illustrate this theme with an account of a genetically modified (GM) blight-resistant potato trial in Norwich, using the Rpi-vnt1.1 gene isolated from a wild relative of potato, Solanum venturii, and introduced by GM methods into the potato variety Desiree. PMID:24535396

  12. Gene flow, invasiveness, and ecological impact of genetically modified crops.

    PubMed

    Warwick, Suzanne I; Beckie, Hugh J; Hall, Linda M

    2009-06-01

    The main environmental concerns about genetically modified (GM) crops are the potential weediness or invasiveness in the crop itself or in its wild or weedy relatives as a result of transgene movement. Here we briefly review evidence for pollen- and seed-mediated gene flow from GM crops to non-GM or other GM crops and to wild relatives. The report focuses on the effect of abiotic and biotic stress-tolerance traits on plant fitness and their potential to increase weedy or invasive tendencies. An evaluation of weediness and invasive traits that contribute to the success of agricultural weeds and invasive plants was of limited value in predicting the effect of biotic and abiotic stress-tolerance GM traits, suggesting context-specific evaluation rather than generalizations. Fitness data on herbicide, insect, and disease resistance, as well as cold-, drought-, and salinity-tolerance traits, are reviewed. We describe useful ecological models predicting the effects of gene flow and altered fitness in GM crops and wild/weedy relatives, as well as suitable mitigation measures. A better understanding of factors controlling population size, dynamics, and range limits in weedy volunteer GM crop and related host or target weed populations is necessary before the effect of biotic and abiotic stress-tolerance GM traits can be fully assessed.

  13. Gene flow from glyphosate-resistant crops.

    PubMed

    Mallory-Smith, Carol; Zapiola, Maria

    2008-04-01

    Gene flow from transgenic glyphosate-resistant crops can result in the adventitious presence of the transgene, which may negatively impact markets. Gene flow can also produce glyphosate-resistant plants that may interfere with weed management systems. The objective of this article is to review the gene flow literature as it pertains to glyphosate-resistant crops. Gene flow is a natural phenomenon not unique to transgenic crops and can occur via pollen, seed and, in some cases, vegetative propagules. Gene flow via pollen can occur in all crops, even those that are considered to be self-pollinated, because all have low levels of outcrossing. Gene flow via seed or vegetative propagules occurs when they are moved naturally or by humans during crop production and commercialization. There are many factors that influence gene flow; therefore, it is difficult to prevent or predict. Gene flow via pollen and seed from glyphosate-resistant canola and creeping bentgrass fields has been documented. The adventitious presence of the transgene responsible for glyphosate resistance has been found in commercial seed lots of canola, corn and soybeans. In general, the glyphosate-resistant trait is not considered to provide an ecological advantage. However, regulators should consider the examples of gene flow from glyphosate-resistant crops when formulating rules for the release of crops with traits that could negatively impact the environment or human health.

  14. Sustainable management of insect-resistant crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop genetically engineered to provide resistance to specific groups of insect pests have been adopted by millions of growers throughout the world. Here we document the effects of transgenic crops on pest population densities, beneficial insect densities and biological control services, insecticide ...

  15. Genetically modified crops: Brazilian law and overview.

    PubMed

    Marinho, C D; Martins, F J O; Amaral Júnior, A T; Gonçalves, L S A; dos Santos, O J A P; Alves, D P; Brasileiro, B P; Peternelli, L A

    2014-07-07

    In Brazil, the first genetically modified (GM) crop was released in 1998, and it is estimated that 84, 78, and 50% of crop areas containing soybean, corn, and cotton, respectively, were transgenic in 2012. This intense and rapid adoption rate confirms that the choice to use technology has been the main factor in developing national agriculture. Thus, this review focuses on understanding these dynamics in the context of farmers, trade relations, and legislation. To accomplish this goal, a survey was conducted using the database of the National Cultivar Registry and the National Service for Plant Variety Protection of the Ministry of Agriculture, Livestock and Supply [Ministério da Agricultura, Pecuária e Abastecimento (MAPA)] between 1998 and October 13, 2013. To date, 36 events have been released: five for soybeans, 18 for corn, 12 for cotton, and one for beans. From these events, 1395 cultivars have been developed and registered: 582 for soybean, 783 for corn and 30 for cotton. Monsanto owns 73.05% of the technologies used to develop these cultivars, while the Dow AgroScience - DuPont partnership and Syngenta have 16.34 and 4.37% ownership, respectively. Thus, the provision of transgenic seeds by these companies is an oligopoly supported by legislation. Moreover, there has been a rapid replacement of conventional crops by GM crops, whose technologies belong almost exclusively to four multinational companies, with the major ownership by Monsanto. These results reflect a warning to the government of the increased dependence on multinational corporations for key agricultural commodities.

  16. The occurrence of antibiotic resistance genes in Taq polymerases and a decontamination method applied to the detection of genetically modified crops.

    PubMed

    Perron, André; Raymond, Philippe; Simard, Robin

    2006-03-01

    Different antibiotic resistance (AR) genes, such as Bla, Tet and NPTII, contaminate commercially available Taq polymerases. The specificity of the AR gene PCR can be increased when using a restriction enzyme-based decontamination of polymerase. The elimination of Taq polymerase contamination allows the use of PCR tests to screen seeds (corn) and processed food for the presence of genetically modified organisms (GMO) based on the detection of AR genes. Without a decontamination procedure for AR genes, PCR screening tests should be interpreted with caution.

  17. Health Considerations Regarding Horizontal Transfer of Microbial Transgenes Present in Genetically Modified Crops

    PubMed Central

    Kleter, Gijs A.

    2005-01-01

    The potential effects of horizontal gene transfer on human health are an important item in the safety assessment of genetically modified organisms. Horizontal gene transfer from genetically modified crops to gut microflora most likely occurs with transgenes of microbial origin. The characteristics of microbial transgenes other than antibiotic-resistance genes in market-approved genetically modified crops are reviewed. These characteristics include the microbial source, natural function, function in genetically modified crops, natural prevalence, geographical distribution, similarity to other microbial genes, known horizontal transfer activity, selective conditions and environments for horizontally transferred genes, and potential contribution to pathogenicity and virulence in humans and animals. The assessment of this set of data for each of the microbial genes reviewed does not give rise to health concerns. We recommend including the above-mentioned items into the premarket safety assessment of genetically modified crops carrying transgenes other than those reviewed in the present study. PMID:16489267

  18. Herbicide-resistant crop biotechnology: potential and pitfalls

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Herbicide-resistant crops are an important agricultural biotechnology that can enable farmers to effectively control weeds without harming their crops. Glyphosate-resistant (i.e. Roundup Ready) crops have been the most commercially successful varieties of herbicide-resistant crops and have been plan...

  19. Current issues connected with usage of genetically modified crops in production of feed and livestock feeding.

    PubMed

    Kwiatek, K; Mazur, M; Sieradzki, Z

    2008-01-01

    Progress, which is brought by new advances in modern molecular biology, allowed interference in the genome of live organisms and gene manipulation. Introducing new genes to the recipient organism enables to give them new features, absent before. Continuous increase in the area of the biotech crops triggers continuous discussion about safety of genetically modified (GM) crops, including food and feed derived from them. Important issue connected with cultivation of genetically modified crops is a horizontal gene transfer and a bacterial antibiotic resistance. Discussion about safety of GM crops concerns also food allergies caused by eating genetically modified food. The problem of genetic modifications of GM crops used for livestock feeding is widely discussed, taking into account Polish feed law.

  20. Genetically modified crops for biomass increase. Genes and strategies.

    PubMed

    Rojas, Cristian Antonio; Hemerly, Adrianna Silva; Ferreira, Paulo Cavalcanti Gomes

    2010-01-01

    Genetically modified crops (GMCs) have been developed to accelerate the creation of new varieties with improved characteristics such as disease resistance, stress tolerance and higher quality composition. However, agriculture, without minimizing its role in food, feed and fiber source, has become important for the energy matrix of many countries. GMCs are also attractive systems that could fulfill the requirements for these new necessities. An increase of crop yields in an environmental friendly system is a new goal for plant biology research in the twenty-first century. In particular, biomass yield improvement is needed to render the use of biofuels economically feasible. In this context, research directed toward increasing biomass production has attracted much attention and a considerable effort is being made to reach new goals. Nonetheless, in some cases differentiated strategies are needed, as biomass improvement requires approaches other than those employed with traditional crops. This review summarizes the various approaches applied so far to modulate plant growth applying molecular biology-based strategies and increase biomass production, and it highlights several outstanding issues about the developmental constraints that must be addressed.

  1. Herbicide-resistant crops: utilities and limitations for herbicide-resistant weed management.

    PubMed

    Green, Jerry M; Owen, Micheal D K

    2011-06-08

    Since 1996, genetically modified herbicide-resistant (HR) crops, particularly glyphosate-resistant (GR) crops, have transformed the tactics that corn, soybean, and cotton growers use to manage weeds. The use of GR crops continues to grow, but weeds are adapting to the common practice of using only glyphosate to control weeds. Growers using only a single mode of action to manage weeds need to change to a more diverse array of herbicidal, mechanical, and cultural practices to maintain the effectiveness of glyphosate. Unfortunately, the introduction of GR crops and the high initial efficacy of glyphosate often lead to a decline in the use of other herbicide options and less investment by industry to discover new herbicide active ingredients. With some exceptions, most growers can still manage their weed problems with currently available selective and HR crop-enabled herbicides. However, current crop management systems are in jeopardy given the pace at which weed populations are evolving glyphosate resistance. New HR crop technologies will expand the utility of currently available herbicides and enable new interim solutions for growers to manage HR weeds, but will not replace the long-term need to diversify weed management tactics and discover herbicides with new modes of action. This paper reviews the strengths and weaknesses of anticipated weed management options and the best management practices that growers need to implement in HR crops to maximize the long-term benefits of current technologies and reduce weed shifts to difficult-to-control and HR weeds.

  2. Herbicide-Resistant Crops: Utilities and Limitations for Herbicide-Resistant Weed Management

    PubMed Central

    2010-01-01

    Since 1996, genetically modified herbicide-resistant (HR) crops, particularly glyphosate-resistant (GR) crops, have transformed the tactics that corn, soybean, and cotton growers use to manage weeds. The use of GR crops continues to grow, but weeds are adapting to the common practice of using only glyphosate to control weeds. Growers using only a single mode of action to manage weeds need to change to a more diverse array of herbicidal, mechanical, and cultural practices to maintain the effectiveness of glyphosate. Unfortunately, the introduction of GR crops and the high initial efficacy of glyphosate often lead to a decline in the use of other herbicide options and less investment by industry to discover new herbicide active ingredients. With some exceptions, most growers can still manage their weed problems with currently available selective and HR crop-enabled herbicides. However, current crop management systems are in jeopardy given the pace at which weed populations are evolving glyphosate resistance. New HR crop technologies will expand the utility of currently available herbicides and enable new interim solutions for growers to manage HR weeds, but will not replace the long-term need to diversify weed management tactics and discover herbicides with new modes of action. This paper reviews the strengths and weaknesses of anticipated weed management options and the best management practices that growers need to implement in HR crops to maximize the long-term benefits of current technologies and reduce weed shifts to difficult-to-control and HR weeds. PMID:20586458

  3. Development of PPO inhibitor-resistant cultures and crops.

    PubMed

    Li, Xianggan; Nicholl, David

    2005-03-01

    Recent progress in the development of protoporphyrinogen oxidase (PPO, Protox) inhibitor-resistant plant cell cultures and crops is reviewed, with emphasis on the molecular and cellular aspects of this topic. PPO herbicide-resistant maize plants have been reported, along with the isolation of plant PPO genes and the isolation of herbicide-resistant mutants. At the same time, PPO inhibitor-resistant rice plants have been developed by expression of the Bacillus subtilis PPO gene via targeting the gene into either chloroplast or cytoplasm. Other attempts to develop PPO herbicide-resistant plants include conventional tissue culture methods, expression of modified co-factors of the protoporphyrin IX binding subunit proteins, over-expression of wild-type plant PPO gene, and engineering of P-450 monooxygenases to degrade the PPO inhibitor.

  4. The state of genetically modified crop regulation in Canada

    PubMed Central

    Smyth, Stuart J

    2014-01-01

    Genetically modified (GM) crops were first commercialized in Canada in 1995 and the 2014 crop represents the 20th year of successful production. Prior to the first commercialization of GM crops, Canada reviewed its existing science-based regulatory framework and adapted the existing framework to allow for risk assessments on the new technology to be undertaken in a timely and efficient manner. The result has been the rapid and widespread adoption of GM varieties of canola, corn and soybeans. The first decade of GM crop production precipitated 2 landmark legal cases relating to patent infringement and economic liability, while the second decade witnessed increased political efforts to have GM crops labeled in Canada as well as significant challenges from the low level comingling of GM crops with non-GM commodities. This article reviews the 20 y of GM crop production in Canada from a social science perspective that includes intellectual property, consumer acceptance and low level presence. PMID:25437238

  5. Genetically Modified Herbicide-Tolerant Crops, Weeds, and Herbicides: Overview and Impact

    NASA Astrophysics Data System (ADS)

    Bonny, Sylvie

    2016-01-01

    Genetically modified (GM) crops have been and continue to be a subject of controversy despite their rapid adoption by farmers where approved. For the last two decades, an important matter of debate has been their impact on pesticide use, particularly for herbicide-tolerant (HT) crops. Some claim that these crops bring about a decrease in herbicide use, while others claim the opposite. In fact, since 1996, most cultivated GMOs have been GMHT crops, which involve the use of an associated herbicide, generally glyphosate. In their very first years of adoption, HT crops often led to some decrease in herbicide use. However, the repetition of glyphosate-tolerant crops and of glyphosate only applications in the same fields without sufficient alternation and herbicide diversity has contributed to the appearance of glyphosate-resistant weeds. These weeds have resulted in a rise in the use of glyphosate and other herbicides. This article explores this situation and the impacts of herbicide-resistant weeds, using an interdisciplinary approach and drawing on recent data. The paper analyzes the spread of GMHT crops worldwide and their consequences on herbicide use in the USA in particular. It then addresses the global development of glyphosate-resistant weeds and their impact, particularly focusing on the USA. Finally, the last section explores how industry, farmers, and weed scientists are coping with the spread of resistant weeds. The concluding comments deal more widely with trends in GM crops.

  6. Genetically Modified Herbicide-Tolerant Crops, Weeds, and Herbicides: Overview and Impact.

    PubMed

    Bonny, Sylvie

    2016-01-01

    Genetically modified (GM) crops have been and continue to be a subject of controversy despite their rapid adoption by farmers where approved. For the last two decades, an important matter of debate has been their impact on pesticide use, particularly for herbicide-tolerant (HT) crops. Some claim that these crops bring about a decrease in herbicide use, while others claim the opposite. In fact, since 1996, most cultivated GMOs have been GMHT crops, which involve the use of an associated herbicide, generally glyphosate. In their very first years of adoption, HT crops often led to some decrease in herbicide use. However, the repetition of glyphosate-tolerant crops and of glyphosate only applications in the same fields without sufficient alternation and herbicide diversity has contributed to the appearance of glyphosate-resistant weeds. These weeds have resulted in a rise in the use of glyphosate and other herbicides. This article explores this situation and the impacts of herbicide-resistant weeds, using an interdisciplinary approach and drawing on recent data. The paper analyzes the spread of GMHT crops worldwide and their consequences on herbicide use in the USA in particular. It then addresses the global development of glyphosate-resistant weeds and their impact, particularly focusing on the USA. Finally, the last section explores how industry, farmers, and weed scientists are coping with the spread of resistant weeds. The concluding comments deal more widely with trends in GM crops.

  7. [Unintended effects assessment of genetically modified crops using omics techniques].

    PubMed

    Zhao, Yan; Li, Yan-Yan

    2013-12-01

    Safety assessment is the essential process for commercial application of genetically modified (GM) crops. Omics techniques can be used to evaluate the safety of GM crops unbiasedly at different biological levels, such as transcripts, proteins and metabolites. In the present review, the researches on unintended effects assessment of GM crops using transcriptomic, proteomic and metabolomic techniques in recent ten years have been summarized. The facts show that the environmental factors (growing area and season) and genotype difference play greater roles than gene insertion does for most unintended variations in GM crops.

  8. [Assessment of allergenicity of genetically modified food crops].

    PubMed

    Schauzu, M; Pöting, A; Rubin, D; Lampen, A

    2012-03-01

    The placing on the European Union's market of genetically modified crops requires authorization by the European Commission which is based on the proof that the derived foods are as safe as their conventional counterparts. The assessment of potential allergenicity is part of the necessary investigations recommended in the updated Guidance Document of the Scientific Panel on Genetically Modified Organisms (GMO) of the European Food Safety Authority (EFSA), which is based on internationally agreed recommendations. All genetically modified crops which so far have been authorized in the European Union were evaluated by the EFSA GMO Panel which considered it unlikely that their overall allergenicity has been altered.

  9. MS-based analytical methodologies to characterize genetically modified crops.

    PubMed

    García-Cañas, Virginia; Simó, Carolina; León, Carlos; Ibáñez, Elena; Cifuentes, Alejandro

    2011-01-01

    The development of genetically modified crops has had a great impact on the agriculture and food industries. However, the development of any genetically modified organism (GMO) requires the application of analytical procedures to confirm the equivalence of the GMO compared to its isogenic non-transgenic counterpart. Moreover, the use of GMOs in foods and agriculture faces numerous criticisms from consumers and ecological organizations that have led some countries to regulate their production, growth, and commercialization. These regulations have brought about the need of new and more powerful analytical methods to face the complexity of this topic. In this regard, MS-based technologies are increasingly used for GMOs analysis to provide very useful information on GMO composition (e.g., metabolites, proteins). This review focuses on the MS-based analytical methodologies used to characterize genetically modified crops (also called transgenic crops). First, an overview on genetically modified crops development is provided, together with the main difficulties of their analysis. Next, the different MS-based analytical approaches applied to characterize GM crops are critically discussed, and include "-omics" approaches and target-based approaches. These methodologies allow the study of intended and unintended effects that result from the genetic transformation. This information is considered to be essential to corroborate (or not) the equivalence of the GM crop with its isogenic non-transgenic counterpart.

  10. Effects of Transgenic Glyphosate-Resistant Crops on Water Quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glyphosate (N-[phosphonomethyl] glycine) is a highly effective, non-selective herbicide. Herbicide-resistant crop (HRC) has been the most successful trait used in transgenic crops throughout the world. Transgenic glyphosate-resistant crops (GRCs) have been commercialized and grown extensively in the...

  11. Is genetically modified crop the answer for the next green revolution?

    PubMed

    Basu, Saikat Kumar; Dutta, Madhuleema; Goyal, Aakash; Bhowmik, Pankaj Kumar; Kumar, Jitendra; Nandy, Sanjib; Scagliusi, Sandra Mansun; Prasad, Rajib

    2010-01-01

    Post-green revolution advances made in biotechnology paved the way of cultivating the high-yielding, stress and disease resistant genetically modified (GM) varieties of wheat, rice, maize cotton and several other crops. The recent rapid commercialization of the genetically modified crops in Asia, Americas and Australia indicates the potentiality of this new technology. GM crops give higher yields and are rich in nutritional values containing vitamins and minerals and can thus can help to alleviate hunger and malnutrition of the growing population in the under developed and developing countries. It could also be possible to develop more biotic and abiotic stress resistant genotypes in these crops where it was difficult to develop due to the unavailability of genes of resistance in the crossing germplasms. However, further research and investigations are needed to popularize the cultivation of these crops in different parts of the world. This review provides an insight of the impact of GM crops on contemporary agriculture across the past few decades, traces its' history across time, highlights new achievements and breakthroughs and discusses the future implication of this powerful technology in the coming few decades.

  12. Molecular characterization of genetically-modified crops: Challenges and strategies.

    PubMed

    Li, Rong; Quan, Sheng; Yan, Xiaofang; Biswas, Sukumar; Zhang, Dabing; Shi, Jianxin

    Molecular characterization lays a foundation for safety assessment and subsequent monitoring of genetically modified (GM) crops. Due to the target-specific nature, conventional polymerase chain reaction (PCR)-based methods cannot comprehensively detect unintended gene insertions, let alone unknown GM events. As more and more new developed GM crops including new plant breeding technology (NPBT) generated crops are in the pipeline for commercialization, alternative -omics approaches, particularly next generation sequencing, have been developed for molecular characterization of authorized or unauthorized GM (UGM) crops. This review summarizes first those methods, addresses their challenges, and discusses possible strategies for molecular characterization of engineered crops generated by NPBT, highlighting needs for a global information-sharing database and cost-effective, accurate and comprehensive molecular characterization approaches.

  13. Genetically modified crops: detection strategies and biosafety issues.

    PubMed

    Kamle, Suchitra; Ali, Sher

    2013-06-15

    Genetically modified (GM) crops are increasingly gaining acceptance but concurrently consumers' concerns are also increasing. The introduction of Bacillus thuringiensis (Bt) genes into the plants has raised issues related to its risk assessment and biosafety. The International Regulations and the Codex guidelines regulate the biosafety requirements of the GM crops. In addition, these bodies synergize and harmonize the ethical issues related to the release and use of GM products. The labeling of GM crops and their products are mandatory if the genetically modified organism (GMO) content exceeds the levels of a recommended threshold. The new and upcoming GM crops carrying multiple stacked traits likely to be commercialized soon warrant sensitive detection methods both at the DNA and protein levels. Therefore, traceability of the transgene and its protein expression in GM crops is an important issue that needs to be addressed on a priority basis. The advancement in the area of molecular biology has made available several bioanalytical options for the detection of GM crops based on DNA and protein markers. Since the insertion of a gene into the host genome may even cause copy number variation, this may be uncovered using real time PCR. Besides, assessing the exact number of mRNA transcripts of a gene, correlation between the template activity and expressed protein may be established. Here, we present an overview on the production of GM crops, their acceptabilities, detection strategies, biosafety issues and potential impact on society. Further, overall future prospects are also highlighted.

  14. Biosafety management and commercial use of genetically modified crops in China.

    PubMed

    Li, Yunhe; Peng, Yufa; Hallerman, Eric M; Wu, Kongming

    2014-04-01

    As a developing country with relatively limited arable land, China is making great efforts for development and use of genetically modified (GM) crops to boost agricultural productivity. Many GM crop varieties have been developed in China in recent years; in particular, China is playing a leading role in development of insect-resistant GM rice lines. To ensure the safe use of GM crops, biosafety risk assessments are required as an important part of the regulatory oversight of such products. With over 20 years of nationwide promotion of agricultural biotechnology, a relatively well-developed regulatory system for risk assessment and management of GM plants has been developed that establishes a firm basis for safe use of GM crops. So far, a total of seven GM crops involving ten events have been approved for commercial planting, and 5 GM crops with a total of 37 events have been approved for import as processing material in China. However, currently only insect-resistant Bt cotton and disease-resistant papaya have been commercially planted on a large scale. The planting of Bt cotton and disease-resistant papaya have provided efficient protection against cotton bollworms and Papaya ringspot virus (PRSV), respectively. As a consequence, chemical application to these crops has been significantly reduced, enhancing farm income while reducing human and non-target organism exposure to toxic chemicals. This article provides useful information for the colleagues, in particular for them whose mother tongue is not Chinese, to clearly understand the biosafety regulation and commercial use of genetically modified crops in China.

  15. Transgenic Herbicide-resistant Crops and Environmental Impacts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transgenic glufosinate- and glyphosate-resistant crops are currently commercialized, and bromoxynil-resistant crops have been removed from the market for economic reasons. Glyphosate-resistant cotton and soybean have become dominant in those countries where they can be grown. Potential effects of gl...

  16. Environmental Impacts of Transgenic Herbicide-Resistant Crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transgenic glufosinate- and glyphosate-resistant crops are currently commercialized, and bromoxynil-resistant crops have been removed from the market for economic reasons. Glyphosate-resistant cotton and soybean have become dominant in those countries where they can be grown. Potential effects of gl...

  17. Ecological impacts of genetically modified crops: ten years of field research and commercial cultivation.

    PubMed

    Sanvido, Olivier; Romeis, Jörg; Bigler, Franz

    2007-01-01

    The worldwide commercial cultivation of genetically modified (GM) crops has raised concerns about potential adverse effects on the environment resulting from the use of these crops. Consequently, the risks of GM crops for the environment, and especially for biodiversity, have been extensively assessed before and during their commercial cultivation. Substantial scientific data on the environmental effects of the currently commercialized GM crops are available today. We have reviewed this scientific knowledge derived from the past 10 years of worldwide experimental field research and commercial cultivation. The review focuses on the currently commercially available GM crops that could be relevant for agriculture in Western and Central Europe (i.e., maize, oilseed rape, and soybean), and on the two main GM traits that are currently commercialized, herbicide tolerance (HT) and insect resistance (IR). The sources of information included peer-reviewed scientific journals, scientific books, reports from regions with extensive GM crop cultivation, as well as reports from international governmental organizations. The data available so far provide no scientific evidence that the cultivation of the presently commercialized GM crops has caused environmental harm. Nevertheless, a number of issues related to the interpretation of scientific data on effects of GM crops on the environment are debated controversially. The present review highlights these scientific debates and discusses the effects of GM crop cultivation on the environment considering the impacts caused by cultivation practices of modern agricultural systems.

  18. Genetically modified crops and small-scale farmers: main opportunities and challenges.

    PubMed

    Azadi, Hossein; Samiee, Atry; Mahmoudi, Hossein; Jouzi, Zeynab; Khachak, Parisa Rafiaani; De Maeyer, Philippe; Witlox, Frank

    2016-01-01

    Although some important features of genetically modified (GM) crops such as insect resistance, herbicide tolerance, and drought tolerance might seem to be beneficial for small-scale farmers, the adoption of GM technology by smallholders is still slight. Identifying pros and cons of using this technology is important to understand the impacts of GM crops on these farmers. This article reviews the main opportunities and challenges of GM crops for small-scale farmers in developing countries. The most significant advantages of GM crops include being independent to farm size, environment protection, improvement of occupational health issues, and the potential of bio-fortified crops to reduce malnutrition. Challenges faced by small-scale farmers for adoption of GM crops comprise availability and accessibility of GM crop seeds, seed dissemination and price, and the lack of adequate information. In addition, R&D and production costs in using GM crops make it difficult for these farmers to adopt the use of these crops. Moreover, intellectual property right regulations may deprive resource poor farmers from the advantages of GM technology. Finally, concerns on socio-economic and environment safety issues are also addressed in this paper.

  19. Commercializing genetically modified crops under EU regulations: objectives and barriers.

    PubMed

    Raybould, Alan; Poppy, Guy M

    2012-01-01

    Agriculture faces serious problems in feeding 9 billion people by 2050: production must be increased and ecosystem services maintained under conditions for growing crops that are predicted to worsen in many parts of the world. A proposed solution is sustainable intensification of agriculture, whereby yields are increased on land that is currently cultivated, so sparing land to deliver other ecosystem services. Genetically modified (GM) crops are already contributing to sustainable intensification through higher yields and lower environmental impacts, and have potential to deliver further significant improvements. Despite their widespread successful use elsewhere, the European Union (EU) has been slow to introduce GM crops: decisions on applications to import GM commodities are lengthy, and decision-making on applications to cultivate GM crops has virtually ceased. Delayed import approvals result in economic losses, particularly in the EU itself as a result of higher commodity prices. Failure to grant cultivation approvals costs EU farmers opportunities to reduce inputs, and results in loss of agricultural research and development from the EU to countries such as the United States and China. Delayed decision-making in the EU ostensibly results from scientific uncertainty about the effects of using GM crops; however, scientific uncertainty may be a means to justify a political decision to restrict cultivation of GM crops in the EU. The problems associated with delayed decision-making will not improve until there is clarity about the EU's agricultural policy objectives, and whether the use of GM crops will be permitted to contribute to achieving those objectives.

  20. A Meta-Analysis of the Impacts of Genetically Modified Crops

    PubMed Central

    Klümper, Wilhelm; Qaim, Matin

    2014-01-01

    Background Despite the rapid adoption of genetically modified (GM) crops by farmers in many countries, controversies about this technology continue. Uncertainty about GM crop impacts is one reason for widespread public suspicion. Objective We carry out a meta-analysis of the agronomic and economic impacts of GM crops to consolidate the evidence. Data Sources Original studies for inclusion were identified through keyword searches in ISI Web of Knowledge, Google Scholar, EconLit, and AgEcon Search. Study Eligibility Criteria Studies were included when they build on primary data from farm surveys or field trials anywhere in the world, and when they report impacts of GM soybean, maize, or cotton on crop yields, pesticide use, and/or farmer profits. In total, 147 original studies were included. Synthesis Methods Analysis of mean impacts and meta-regressions to examine factors that influence outcomes. Results On average, GM technology adoption has reduced chemical pesticide use by 37%, increased crop yields by 22%, and increased farmer profits by 68%. Yield gains and pesticide reductions are larger for insect-resistant crops than for herbicide-tolerant crops. Yield and profit gains are higher in developing countries than in developed countries. Limitations Several of the original studies did not report sample sizes and measures of variance. Conclusion The meta-analysis reveals robust evidence of GM crop benefits for farmers in developed and developing countries. Such evidence may help to gradually increase public trust in this technology. PMID:25365303

  1. Regulatory options for genetically modified crops in India.

    PubMed

    Choudhary, Bhagirath; Gheysen, Godelieve; Buysse, Jeroen; van der Meer, Piet; Burssens, Sylvia

    2014-02-01

    The introduction of semi-dwarfing, high-yielding and nutrients-responsive crop varieties in the 1960s and 1970s alleviated the suffering of low crop yield, food shortages and epidemics of famine in India and other parts of the Asian continent. Two semi-dwarfing genes, Rht in wheat and Sd-1 in rice heralded the green revolution for which Dr. Norman Borlaug was awarded the Nobel Peace Prize in 1970. In contrast, the revolutionary new genetics of crop improvement shamble over formidable obstacles of regulatory delays, political interferences and public misconceptions. India benefited immensely from the green revolution and is now grappling to deal with the nuances of GM crops. The development of GM mustard discontinued prematurely in 2001 and insect-resistant Bt cotton varieties were successfully approved for commercial cultivation in 2002 in an evolving nature of regulatory system. However, the moratorium on Bt brinjal by MOEF in 2010 meant a considerable detour from an objective, science-based, rigorous institutional process of regulatory approval to a more subjective, nonscience-driven, political decision-making process. This study examines what ails the regulatory system of GM crops in India and the steps that led to the regulatory logjam. Responding to the growing challenges and impediments of existing biosafety regulation, it suggests options that are critical for GM crops to take roots for a multiplier harvest.

  2. Glyphosate-resistant crops: history, status and future.

    PubMed

    Dill, Gerald M

    2005-03-01

    The commercial launch of glyphosate-resistant soybeans in 1996 signaled the beginning of a new era in weed management in row crops. Today, over 80% of the soybeans grown in the USA are glyphosate resistant. Since that time, many crops have been transformed that have allowed crop applications of many classes of herbicide chemistries. Crops currently under production include maize, soybean, cotton and canola. Transformation technology and selection methods have improved and the rate of development as well as the breadth of crops being considered as commercial targets has increased. On the basis of recent adoption rates by growers around the world, it appears that glyphosate-resistant crops will continue to grow in number and in hectares planted. However, global public acceptance of biotechnology-derived products will continue to impact the rate of adoption of this and other new innovations derived from transformation technology.

  3. Cross-fertilization between genetically modified and non-genetically modified maize crops in Uruguay.

    PubMed

    Galeano, Pablo; Debat, Claudio Martínez; Ruibal, Fabiana; Fraguas, Laura Franco; Galván, Guillermo A

    2010-01-01

    The cultivation of genetically modified (GM) Bt maize (Zea mays L.) events MON810 and Bt11 is permitted in Uruguay. Local regulations specify that 10% of the crop should be a non-GM cultivar as refuge area for biodiversity, and the distance from other non-GM maize crops should be more than 250 m in order to avoid cross-pollination. However, the degree of cross-fertilization between maize crops in Uruguay is unknown. The level of adventitious presence of GM material in non-GM crops is a relevant issue for organic farming, in situ conservation of genetic resources and seed production. In the research reported here, the occurrence and frequency of cross-fertilization between commercial GM and non-GM maize crops in Uruguay was assessed. The methodology comprised field sampling and detection using DAS-ELISA and PCR. Five field-pair cases where GM maize crops were grown near non-GM maize crops were identified. These cases had the potential to cross-fertilize considering the distance between crops and the similarity of the sowing dates. Adventitious presence of GM material in the offspring of non-GM crops was found in three of the five cases. Adventitious presence of event MON810 or Bt11 in non-GM maize, which were distinguished using specific primers, matched the events in the putative sources of transgenic pollen. Percentages of transgenic seedlings in the offspring of the non-GM crops were estimated as 0.56%, 0.83% and 0.13% for three sampling sites with distances of respectively 40, 100 and 330 m from the GM crops. This is a first indication that adventitious presence of transgenes in non-GM maize crops will occur in Uruguay if isolation by distance and/or time is not provided. These findings contribute to the evaluation of the applicability of the "regulated coexistence policy" in Uruguay.

  4. Global Adoption of Genetically Modified (GM) Crops: Challenges for the Public Sector.

    PubMed

    Huesing, Joseph E; Andres, David; Braverman, Michael P; Burns, Andrea; Felsot, Allan S; Harrigan, George G; Hellmich, Richard L; Reynolds, Alan; Shelton, Anthony M; Jansen van Rijssen, Wilna; Morris, E Jane; Eloff, Jacobus N

    2016-01-20

    Advances in biotechnology continue to drive the development of a wide range of insect-protected, herbicide-tolerant, stress-tolerant, and nutritionally enhanced genetically modified (GM) crops, yet societal and public policy considerations may slow their commercialization. Such restrictions may disproportionately affect developing countries, as well as smaller entrepreneurial and public sector initiatives. The 2014 IUPAC International Congress of Pesticide Chemistry (San Francisco, CA, USA; August 2014) included a symposium on "Challenges Associated with Global Adoption of Agricultural Biotechnology" to review current obstacles in promoting GM crops. Challenges identified by symposium presenters included (i) poor public understanding of GM technology and the need for enhanced communication strategies, (ii) nonharmonized and prescriptive regulatory requirements, and (iii) limited experience with regulations and product development within some public sector programs. The need for holistic resistance management programs to enable the most effective use of insect-protected crops was also a point of emphasis. This paper provides details on the symposium discussion and provides background information that can be used in support of further adoption of beneficial GM crops. Overall, it emphasizes that global adoption of modern agricultural biotechnology has not only provided benefits to growers and consumers but has great potential to provide solutions to an increasing global population and diminishing agricultural land. This potential will be realized by continued scientific innovation, harmonized regulatory systems, and broader communication of the benefits of the high-yielding, disease-resistant, and nutritionally enhanced crops attainable through modern biotechnology.

  5. Risk assessment of genetically modified crops for nutrition and health.

    PubMed

    Magaña-Gómez, Javier A; de la Barca, Ana M Calderón

    2009-01-01

    The risk assessment of genetically modified (GM) crops for human nutrition and health has not been systematic. Evaluations for each GM crop or trait have been conducted using different feeding periods, animal models, and parameters. The most common result is that GM and conventional sources induce similar nutritional performance and growth in animals. However, adverse microscopic and molecular effects of some GM foods in different organs or tissues have been reported. Diversity among the methods and results of the risk assessments reflects the complexity of the subject. While there are currently no standardized methods to evaluate the safety of GM foods, attempts towards harmonization are on the way. More scientific effort is necessary in order to build confidence in the evaluation and acceptance of GM foods.

  6. Swedish farmers attitudes, expectations and fears in relation to growing genetically modified crops.

    PubMed

    Lehrman, Anna; Johnson, Katy

    2008-01-01

    This study evaluates a survey about Swedish farmers' attitude towards genetically modified (GM) crops, and their perception concerning potential benefits and drawbacks that cropping of an insect resistant (IR) GM variety would involve. The questions were "tick a box" choices, included in a yearly omnibus survey sent to 1000 Swedish farmers (68% response rate). The results showed that a majority of the farmers were negative, although almost one third claimed to be neutral to GM crops. The farmers recognized several benefits both in terms of agricultural production and for the environment, but they were also highly concerned about the consumers' unwillingness to buy GM products. Farmers perceived an increase in yield, but nearly as many farmers thought that there would be no benefits with growing an IR GM crop. Several differences in hopes and concerns of the farmers surveyed were revealed when they were divided in positive, neutral and negative groups. Farmers negative to GM were more concerned than positive farmers about IR GM crops being dangerous for humans, livestock or other organisms to consume. GM-positive farmers seemed to be most concerned about potential problems with growing a marketable crop and expensive seeds, but saw a reduced health risk to the grower, due to less use of pesticides, as a possible benefit. The results among the GM-neutral farmers were in most cases closely related to the positive farmers' choices, implying that they believe that there are advantages with growing an IR GM crop, but also fear potential drawbacks. This general uncertainty about GM IR crops may prevent them from accepting the new technology.

  7. Genetically modified crops: success, safety assessment, and public concern.

    PubMed

    Singh, Om V; Ghai, Shivani; Paul, Debarati; Jain, Rakesh K

    2006-08-01

    With the emergence of transgenic technologies, new ways to improve the agronomic performance of crops for food, feed, and processing applications have been devised. In addition, ability to express foreign genes using transgenic technologies has opened up options for producing large quantities of commercially important industrial or pharmaceutical products in plants. Despite this high adoption rate and future promises, there is a multitude of concerns about the impact of genetically modified (GM) crops on the environment. Potential contamination of the environment and food chains has prompted detailed consideration of how such crops and the molecules that they produce can be effectively isolated and contained. One of the reasonable steps after creating a transgenic plant is to evaluate its potential benefits and risks to the environment and these should be compared to those generated by traditional agricultural practices. The precautionary approach in risk management of GM plants may make it necessary to monitor significant wild and weed populations that might be affected by transgene escape. Effective risk assessment and monitoring mechanisms are the basic prerequisites of any legal framework to adequately address the risks and watch out for new risks. Several agencies in different countries monitor the release of GM organisms or frame guidelines for the appropriate application of recombinant organisms in agro-industries so as to assure the safe use of recombinant organisms and to achieve sound overall development. We feel that it is important to establish an internationally harmonized framework for the safe handling of recombinant DNA organisms within a few years.

  8. Bi-trophic mathematical model for pest adaptation to a resistant crop.

    PubMed

    Hillier, Jonathan G; Birch, A Nicholas E

    2002-04-07

    A version of the Lotka-Volterra predator-prey model with logistic crop growth is modified to explore the rate of adaptation of a herbivore to a pest-resistant crop. This provides a phenotypic model for the evolution of resistance in a population comprising three different pest types each defined by differing parameter values for respiration rate and crop palatability. Expressions estimating the rates of increase of the fitter pest types are obtained as a function of the food qualities, and respiration and mortality rates. Potential strategies for delaying the rate of adaptation with regard to the expressions derived above, via the use of pest-susceptible refugia and natural enemies, are discussed. Although the model is formulated as one in which a single gene is the factor conferring resistance it can be interpreted and used independently of this.

  9. Food Allergy - Basic Mechanisms and Applications to Identifying Risks Associated with Plant Incorporated Pesticides and Other Genetically Modified Crops

    EPA Science Inventory

    Food allergy is a relatively new concern for toxicologists as a result of the incorporation of novel proteins into food crops in order to promote resistance to pests and other stresses, improve nutrition, or otherwise modify the phenotype. Food allergy can manifest as inflammatio...

  10. Natural Enemies Delay Insect Resistance to Bt Crops

    PubMed Central

    Liu, Xiaoxia; Chen, Mao; Collins, Hilda L.; Onstad, David W.; Roush, Richard T.; Zhang, Qingwen; Earle, Elizabeth D.; Shelton, Anthony M.

    2014-01-01

    We investigated whether development of resistance to a Bt crop in the presence of a natural enemy would be slower than without the natural enemy and whether biological control, in conjunction with a Bt crop, could effectively suppress the pest population. Additionally, we investigated whether insecticide-sprayed refuges of non-Bt crops would delay or accelerate resistance to the Bt crop. We used a system of Bt broccoli expressing Cry1Ac, a population of the pest Plutella xylostella with a low frequency of individuals resistant to Cry1Ac and the insecticide spinosad, and a natural enemy, Coleomegilla maculata, to conduct experiments over multiple generations. The results demonstrated that after 6 generations P. xylostella populations were very low in the treatment containing C. maculata and unsprayed non-Bt refuge plants. Furthermore, resistance to Bt plants evolved significantly slower in this treatment. In contrast, Bt plants with no refuge were completely defoliated in treatments without C. maculata after 4–5 generations. In the treatment containing sprayed non-Bt refuge plants and C. maculata, the P. xylostella population was low, although the speed of resistance selection to Cry1Ac was significantly increased. These data demonstrate that natural enemies can delay resistance to Bt plants and have significant implications for integrated pest management (IPM) with Bt crops. PMID:24595158

  11. Integrating insect-resistant GM Crops in pest management systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2006, GM cotton and maize with insect resistance were grown on 12.1 and 20.1 million hectares in 9 and 13 countries, respectively. These insect resistant GM crops produce various Cry toxins from Bacillus thuringiensis (Bt) and provide highly selective and effective control of lepidopteran and col...

  12. Resistance Management Research for PIP Crops

    EPA Science Inventory

    A significant increase in genetically modified corn planting driven by biofuel demand is expected for future planted acreages approaching 80% of total corn plantings in 2009. As demand increases, incidence of farmer non-compliance with mandated non-genetically modified refuge is...

  13. Technical performance of some commercial glyphosate-resistant crops.

    PubMed

    Pline-Srnic, Wendy

    2005-03-01

    Glyphosate-resistant (GR) crops have been sold commercially in the USA since 1996. The use of glyphosate alone or with conventional pre- and post-emergence herbicides with different modes of action gives growers many options for affordable, safe, easy, effective wide-spectrum weed control. Despite the overwhelming popularity of this technology, technical issues have surfaced from time to time as US growers adopt these crops for use on their farms. The types of concern raised by growers vary from year to year depending on the crop and the environment, but include perceptions of increased sensitivity to diseases, increased fruit abortion, reduced pollination efficiency, increased sensitivity to environmental stress, and differences in yield and agronomic characteristics between transgenic and sister conventional varieties. Although several glyphosate-resistant crops are commercially available, maize, soybean and cotton constitute the largest cultivated acreage and have likewise been associated with the highest number of technical concerns. Because glyphosate is rapidly translocated to and accumulates in metabolic sink tissues, reproductive tissues and roots are particularly vulnerable. Increased sensitivity to glyphosate in reproductive tissues has been documented in both glyphosate-resistant cotton and maize, and results in reduced pollen production and viability, or increased fruit abortion. Glyphosate treatments have the potential to affect relationships between the GR crop, plant pathogens, plant pests and symbiotic micro-organisms, although management practices can also have a large impact. Despite these potential technical concerns, this technology remains popular, and is a highly useful tool for weed control in modern crop production.

  14. Unintended effects in genetically modified crops: revealed by metabolomics?

    PubMed

    Rischer, Heiko; Oksman-Caldentey, Kirsi-Marja

    2006-03-01

    In Europe the commercialization of food derived from genetically modified plants has been slow because of the complex regulatory process and the concerns of consumers. Risk assessment is focused on potential adverse effects on humans and the environment, which could result from unintended effects of genetic modifications: unintended effects are connected to changes in metabolite levels in the plants. One of the major challenges is how to analyze the overall metabolite composition of GM plants in comparison to conventional cultivars, and one possible solution is offered by metabolomics. The ultimate aim of metabolomics is the identification and quantification of all small molecules in an organism; however, a single method enabling complete metabolome analysis does not exist. Given a comprehensive extraction method, a hierarchical strategy--starting with global fingerprinting and followed by complementary profiling attempts--is the most logical and economic approach to detect unintended effects in GM crops.

  15. Characteristics and safety assessment of intractable proteins in genetically modified crops.

    PubMed

    Bushey, Dean F; Bannon, Gary A; Delaney, Bryan F; Graser, Gerson; Hefford, Mary; Jiang, Xiaoxu; Lee, Thomas C; Madduri, Krishna M; Pariza, Michael; Privalle, Laura S; Ranjan, Rakesh; Saab-Rincon, Gloria; Schafer, Barry W; Thelen, Jay J; Zhang, John X Q; Harper, Marc S

    2014-07-01

    Genetically modified (GM) crops may contain newly expressed proteins that are described as "intractable". Safety assessment of these proteins may require some adaptations to the current assessment procedures. Intractable proteins are defined here as those proteins with properties that make it extremely difficult or impossible with current methods to express in heterologous systems; isolate, purify, or concentrate; quantify (due to low levels); demonstrate biological activity; or prove equivalency with plant proteins. Five classes of intractable proteins are discussed here: (1) membrane proteins, (2) signaling proteins, (3) transcription factors, (4) N-glycosylated proteins, and (5) resistance proteins (R-proteins, plant pathogen recognition proteins that activate innate immune responses). While the basic tiered weight-of-evidence approach for assessing the safety of GM crops proposed by the International Life Sciences Institute (ILSI) in 2008 is applicable to intractable proteins, new or modified methods may be required. For example, the first two steps in Tier I (hazard identification) analysis, gathering of applicable history of safe use (HOSU) information and bioinformatics analysis, do not require protein isolation. The extremely low level of expression of most intractable proteins should be taken into account while assessing safety of the intractable protein in GM crops. If Tier II (hazard characterization) analyses requiring animal feeding are judged to be necessary, alternatives to feeding high doses of pure protein may be needed. These alternatives are discussed here.

  16. Weed control changes and genetically modified herbicide tolerant crops in the USA 1996-2012.

    PubMed

    Brookes, Graham

    2014-01-01

    Crops that have been genetically modified (GM) to be tolerant to herbicides have been widely grown in the USA since 1996. The rapid and widespread adoption of this technology reflects the important economic and environmental benefits that farmers have derived from its use (equal to $21.7 billion additional farm income and a 225 million kg reduction in herbicide active ingredient use 1996-2012). During this time, weed control practices in these crops relative to the 'conventional alternative' have evolved to reflect experience of using the technology, the challenges that have arisen and the increasing focus in recent years on developing sustainable production systems. This paper examines the evidence on the changing nature of herbicides used with these crops and in particular how farmers addressed the challenge of weed resistance. The evidence shows that use of the technology has resulted in a net reduction in both the amount of herbicide used and the associated environmental impact, as measured by the EIQ indicator when compared to what can reasonably be expected if the area planted to GM HT crops reverted to conventional production methods. It also facilitated many farmers being able to derive the economic and environmental benefits associated with switching from a plough-based to a no tillage or conservation tillage production system. In terms of herbicide use, the technology has also contributed to a change the profile of herbicides used. A broad range of, mostly selective herbicides has been replaced by one or 2 broad-spectrum herbicides (mostly glyphosate) used in conjunction with one or 2 other (complementary) herbicides. Since the mid-2000s, the average amount of herbicide applied and the associated environmental load, as measured by the EIQ indicator, have increased on both GM HT and conventional crops. A primary reason for these changes has been increasing incidence of weed species developing populations resistant to herbicides and increased awareness of

  17. Weed control changes and genetically modified herbicide tolerant crops in the USA 1996–2012

    PubMed Central

    Brookes, Graham

    2014-01-01

    Crops that have been genetically modified (GM) to be tolerant to herbicides have been widely grown in the USA since 1996. The rapid and widespread adoption of this technology reflects the important economic and environmental benefits that farmers have derived from its use (equal to $21.7 billion additional farm income and a 225 million kg reduction in herbicide active ingredient use 1996–2012). During this time, weed control practices in these crops relative to the ‘conventional alternative’ have evolved to reflect experience of using the technology, the challenges that have arisen and the increasing focus in recent years on developing sustainable production systems. This paper examines the evidence on the changing nature of herbicides used with these crops and in particular how farmers addressed the challenge of weed resistance. The evidence shows that use of the technology has resulted in a net reduction in both the amount of herbicide used and the associated environmental impact, as measured by the EIQ indicator when compared to what can reasonably be expected if the area planted to GM HT crops reverted to conventional production methods. It also facilitated many farmers being able to derive the economic and environmental benefits associated with switching from a plough-based to a no tillage or conservation tillage production system. In terms of herbicide use, the technology has also contributed to a change the profile of herbicides used. A broad range of, mostly selective herbicides has been replaced by one or 2 broad-spectrum herbicides (mostly glyphosate) used in conjunction with one or 2 other (complementary) herbicides. Since the mid-2000s, the average amount of herbicide applied and the associated environmental load, as measured by the EIQ indicator, have increased on both GM HT and conventional crops. A primary reason for these changes has been increasing incidence of weed species developing populations resistant to herbicides and increased

  18. Current state of herbicides in herbicide-resistant crops.

    PubMed

    Green, Jerry M

    2014-09-01

    Current herbicide and herbicide trait practices are changing in response to the rapid spread of glyphosate-resistant weeds. Growers urgently needed glyphosate when glyphosate-resistant crops became available because weeds were becoming widely resistant to most commonly used selective herbicides, making weed management too complex and time consuming for large farm operations. Glyphosate made weed management easy and efficient by controlling all emerged weeds at a wide range of application timings. However, the intensive use of glyphosate over wide areas and concomitant decline in the use of other herbicides led eventually to the widespread evolution of weeds resistant to glyphosate. Today, weeds that are resistant to glyphosate and other herbicide types are threatening current crop production practices. Unfortunately, all commercial herbicide modes of action are over 20 years old and have resistant weed problems. The severity of the problem has prompted the renewal of efforts to discover new weed management technologies. One technology will be a new generation of crops with resistance to glyphosate, glufosinate and other existing herbicide modes of action. Other technologies will include new chemical, biological, cultural and mechanical methods for weed management. From the onset of commercialization, growers must now preserve the utility of new technologies by integrating their use with other weed management technologies in diverse and sustainable systems.

  19. Weed species shifts in glyphosate-resistant crops.

    PubMed

    Owen, Micheal D K

    2008-04-01

    The adoption of glyphosate-based crop production systems has been one of the most important revolutions in the history of agriculture. Changes in weed communities owing to species that do not respond to current glyphosate-based management tactics are rapidly increasing. Clearly, glyphosate-resistant crops (GRCs) do not influence weeds any more than non-transgenic crops. For most crops, the trait itself is essentially benign in the environment. Rather, the weed control tactics imposed by growers create the ecological selection pressure that ultimately changes the weed communities. This is seen in the adoption of conservation tillage and weed management programs that focus on one herbicide mode of action and have hastened several important weed population shifts. Tillage (disturbance) is one of the primary factors that affect changes in weed communities. The intense selection pressure from herbicide use will result in the evolution of herbicide-resistant weed biotypes or shifts in the relative prominence of one weed species in the weed community. Changes in weed communities are inevitable and an intrinsic consequence of growing crops over time. The glyphosate-based weed management tactics used in GRCs impose the selection pressure that supports weed population shifts. Examples of weed population shifts in GRCs include common waterhemp [Amaranthus tuberculatus (Moq ex DC) JD Sauer], horseweed (Conyza canadensis L), giant ragweed (Ambrosia trifida L) and other relatively new weed problems. Growers have handled these weed population shifts with varying success depending on the crop.

  20. The impact of altered herbicide residues in transgenic herbicide-resistant crops on standard setting for herbicide residues.

    PubMed

    Kleter, Gijs A; Unsworth, John B; Harris, Caroline A

    2011-10-01

    The global area covered with transgenic (genetically modified) crops has rapidly increased since their introduction in the mid-1990s. Most of these crops have been rendered herbicide resistant, for which it can be envisaged that the modification has an impact on the profile and level of herbicide residues within these crops. In this article, the four main categories of herbicide resistance, including resistance to acetolactate-synthase inhibitors, bromoxynil, glufosinate and glyphosate, are reviewed. The topics considered are the molecular mechanism underlying the herbicide resistance, the nature and levels of the residues formed and their impact on the residue definition and maximum residue limits (MRLs) defined by the Codex Alimentarius Commission and national authorities. No general conclusions can be drawn concerning the nature and level of residues, which has to be done on a case-by-case basis. International residue definitions and MRLs are still lacking for some herbicide-crop combinations, and harmonisation is therefore recommended.

  1. Development of agribiotechnology and biosafety regulations used to assess safety of genetically modified crops in Bangladesh.

    PubMed

    Nasiruddin, Khondoker M; Nasim, Anwar

    2007-01-01

    Bangladesh is on the verge of adopting genetically modified (GM) crops for commercial cultivation and consumption as feed and food. Most of the laboratories are engaged in tissue culture and molecular characterization on plants, whereas some have started living modified organism research with shortages of trained manpower, infrastructure, and funding. Nutritionally improved Golden Rice, biotech brinjal, and late blight-resistant potato are in contained trials in a greenhouse, and potato ring spot virus-resistant papaya is in the process of approval for a field trial. The government has taken some initiative in support of GM organism research, which include the formation of a Biotechnology Department in all institutes and the formation of the apex body, the National Task Force Committee on Biotechnology of Bangladesh under the chairpersonship of the Prime Minister. Biosafety policy guidelines and related aspects of biotechnology issues have been approved, and the laws are in the process of being promulgated. Being a party to the Cartagena Protocol, proper biosafety measures are regulated by the appropriate authority as stated. Although there are no laws made yet directly for biosafety of GM crops/foods, the relevant laws on agriculture, medicine, food, import, trade, environment, etc. may suffice and explain the situation.

  2. Can pyramids and seed mixtures delay resistance to Bt crops?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The primary strategy for delaying evolution of pest resistance to transgenic crops that produce insecticidal proteins from Bacillus thuringiensis (Bt) entails refuges of plants that do not produce Bt toxins and thus allow survival of susceptible pests. Recent advances include using refuges together...

  3. Robust crop resistance to broadleaf and grass herbicides provided by aryloxyalkanoate dioxygenase transgenes.

    PubMed

    Wright, Terry R; Shan, Guomin; Walsh, Terence A; Lira, Justin M; Cui, Cory; Song, Ping; Zhuang, Meibao; Arnold, Nicole L; Lin, Gaofeng; Yau, Kerrm; Russell, Sean M; Cicchillo, Robert M; Peterson, Mark A; Simpson, David M; Zhou, Ning; Ponsamuel, Jayakumar; Zhang, Zhanyuan

    2010-11-23

    Engineered glyphosate resistance is the most widely adopted genetically modified trait in agriculture, gaining widespread acceptance by providing a simple robust weed control system. However, extensive and sustained use of glyphosate as a sole weed control mechanism has led to field selection for glyphosate-resistant weeds and has induced significant population shifts to weeds with inherent tolerance to glyphosate. Additional weed control mechanisms that can complement glyphosate-resistant crops are, therefore, urgently needed. 2,4-dichlorophenoxyacetic acid (2,4-D) is an effective low-cost, broad-spectrum herbicide that controls many of the weeds developing resistance to glyphosate. We investigated the substrate preferences of bacterial aryloxyalkanoate dioxygenase enzymes (AADs) that can effectively degrade 2,4-D and have found that some members of this class can act on other widely used herbicides in addition to their activity on 2,4-D. AAD-1 cleaves the aryloxyphenoxypropionate family of grass-active herbicides, and AAD-12 acts on pyridyloxyacetate auxin herbicides such as triclopyr and fluroxypyr. Maize plants transformed with an AAD-1 gene showed robust crop resistance to aryloxyphenoxypropionate herbicides over four generations and were also not injured by 2,4-D applications at any growth stage. Arabidopsis plants expressing AAD-12 were resistant to 2,4-D as well as triclopyr and fluroxypyr, and transgenic soybean plants expressing AAD-12 maintained field resistance to 2,4-D over five generations. These results show that single AAD transgenes can provide simultaneous resistance to a broad repertoire of agronomically important classes of herbicides, including 2,4-D, with utility in both monocot and dicot crops. These transgenes can help preserve the productivity and environmental benefits of herbicide-resistant crops.

  4. Robust crop resistance to broadleaf and grass herbicides provided by aryloxyalkanoate dioxygenase transgenes

    PubMed Central

    Wright, Terry R.; Shan, Guomin; Walsh, Terence A.; Lira, Justin M.; Cui, Cory; Song, Ping; Zhuang, Meibao; Arnold, Nicole L.; Lin, Gaofeng; Yau, Kerrm; Russell, Sean M.; Cicchillo, Robert M.; Peterson, Mark A.; Simpson, David M.; Zhou, Ning; Ponsamuel, Jayakumar; Zhang, Zhanyuan

    2010-01-01

    Engineered glyphosate resistance is the most widely adopted genetically modified trait in agriculture, gaining widespread acceptance by providing a simple robust weed control system. However, extensive and sustained use of glyphosate as a sole weed control mechanism has led to field selection for glyphosate-resistant weeds and has induced significant population shifts to weeds with inherent tolerance to glyphosate. Additional weed control mechanisms that can complement glyphosate-resistant crops are, therefore, urgently needed. 2,4-dichlorophenoxyacetic acid (2,4-D) is an effective low-cost, broad-spectrum herbicide that controls many of the weeds developing resistance to glyphosate. We investigated the substrate preferences of bacterial aryloxyalkanoate dioxygenase enzymes (AADs) that can effectively degrade 2,4-D and have found that some members of this class can act on other widely used herbicides in addition to their activity on 2,4-D. AAD-1 cleaves the aryloxyphenoxypropionate family of grass-active herbicides, and AAD-12 acts on pyridyloxyacetate auxin herbicides such as triclopyr and fluroxypyr. Maize plants transformed with an AAD-1 gene showed robust crop resistance to aryloxyphenoxypropionate herbicides over four generations and were also not injured by 2,4-D applications at any growth stage. Arabidopsis plants expressing AAD-12 were resistant to 2,4-D as well as triclopyr and fluroxypyr, and transgenic soybean plants expressing AAD-12 maintained field resistance to 2,4-D over five generations. These results show that single AAD transgenes can provide simultaneous resistance to a broad repertoire of agronomically important classes of herbicides, including 2,4-D, with utility in both monocot and dicot crops. These transgenes can help preserve the productivity and environmental benefits of herbicide-resistant crops. PMID:21059954

  5. Effects of modified atmosphere on crop productivity and mineral content

    NASA Astrophysics Data System (ADS)

    Chagvardieff, P.; Dimon, B.; Souleimanov, A.; Massimino, D.; Le Bras, S.; Péan, M.; Louche-Teissandier, D.

    1997-01-01

    Wheat, potato, pea and tomato crops were cultivated from seeding to harvest in a controlled and confined growth chamber at elevated CO_2 concentration (3700 muL.L^-1) to examine the effects on biomass production and edible part yields. Different responses to high CO_2 were recorded, ranging from a decline in productivity for wheat, to slight stimulation for potatoes, moderate increase for tomatoes, and very large enhancement for pea. Mineral content in wheat and pea seeds was not greatly modified by the elevated CO_2. Short-term experiments (17 d) were conducted on potato at high (3700 muL.L^-1) and very high (20,000 muL.L^-1) CO_2 concentration and/or low O_2 partial pressure (~ 20,600 muL.L^-1 or 2 kPa). Low O_2 was more effective than high CO_2 in total biomass accumulation, but development was affected: Low O_2 inhibited tuberization, while high CO_2 significantly increased production of tubers.

  6. Metabolomics of Disease Resistance in Crops.

    PubMed

    Arbona, Vicent; Gómez-Cadenas, Aurelio

    2016-01-01

    Plants are continuously exposed to the attack of invasive microorganisms, such as fungi or bacteria, and also viruses. To fight these attackers, plants develop different metabolic and genetic responses whose final outcome is the production of either toxic compounds that kill the pathogen or deter its growth, and/or semiotic molecules that alert other individuals from the same plant species. These molecules are derived from the secondary metabolism and their production is induced upon detection of a pathogen-associated molecular pattern (PAMP). These PAMPs are different molecules that are perceived by the host cell triggering defense responses. PAMP-elicited compounds are highly diverse and specific of every plant species and can be divided into preformed metabolites or phytoanticipins that are converted into toxic molecules upon pathogen perception, and toxic metabolites or phytoalexins that are produced only upon pathogen attack. Moreover, plant volatile emissions are also modified in response to pathogen attack to alert neighboring individuals or to make plants less attractive to pathogen vector arthropods. Plant metabolite profiling techniques have allowed the identification of novel antimicrobial molecules that are induced upon elicitation. However, more studies are required to assess the specific function of metabolites or metabolite blends on plant-microbe interactions.

  7. Modified fire-resistant foams forseat cushions

    NASA Technical Reports Server (NTRS)

    Gagliani, J.; Lee, R.; Sorathia, U. A. K.; Wilcoxson, A. L.

    1981-01-01

    Modified polyimide-polymer resins are precursors for new family of resilient fire-resistant foams. Terpolyimide foams containing long-chain aliphatic diamines withstand 50,000 cycles of compression over a 200 pound load - an equivalent of 3 years of continuous use as seat cushion filler.

  8. Can Pyramids and Seed Mixtures Delay Resistance to Bt Crops?

    PubMed

    Carrière, Yves; Fabrick, Jeffrey A; Tabashnik, Bruce E

    2016-04-01

    The primary strategy for delaying the evolution of pest resistance to transgenic crops that produce insecticidal proteins from Bacillus thuringiensis (Bt) entails refuges of plants that do not produce Bt toxins and thus allow survival of susceptible pests. Recent advances include using refuges together with Bt crop 'pyramids' that make two or more Bt toxins effective against the same pest, and planting seed mixtures yielding random distributions of pyramided Bt and non-Bt corn plants within fields. We conclude that conditions often deviate from those favoring the success of pyramids and seed mixtures, particularly against pests with low inherent susceptibility to Bt toxins. For these problematic pests, promising approaches include using larger refuges and integrating Bt crops with other pest management tactics.

  9. Challenges in testing genetically modified crops for potential increases in endogenous allergen expression for safety.

    PubMed

    Panda, R; Ariyarathna, H; Amnuaycheewa, P; Tetteh, A; Pramod, S N; Taylor, S L; Ballmer-Weber, B K; Goodman, R E

    2013-02-01

    Premarket, genetically modified (GM) plants are assessed for potential risks of food allergy. The major risk would be transfer of a gene encoding an allergen or protein nearly identical to an allergen into a different food source, which can be assessed by specific serum testing. The potential that a newly expressed protein might become an allergen is evaluated based on resistance to digestion in pepsin and abundance in food fractions. If the modified plant is a common allergenic source (e.g. soybean), regulatory guidelines suggest testing for increases in the expression of endogenous allergens. Some regulators request evaluating endogenous allergens for rarely allergenic plants (e.g. maize and rice). Since allergic individuals must avoid foods containing their allergen (e.g. peanut, soybean, maize, or rice), the relevance of the tests is unclear. Furthermore, no acceptance criteria are established and little is known about the natural variation in allergen concentrations in these crops. Our results demonstrate a 15-fold difference in the major maize allergen, lipid transfer protein between nine varieties, and complex variation in IgE binding to various soybean varieties. We question the value of evaluating endogenous allergens in GM plants unless the intent of the modification was production of a hypoallergenic crop.

  10. Effects of genetically modified herbicide-tolerant cropping systems on weed seedbanks in two years of following crops.

    PubMed

    Firbank, L G; Rothery, P; May, M J; Clark, S J; Scott, R J; Stuart, R C; Boffey, C W H; Brooks, D R; Champion, G T; Haughton, A J; Hawes, C; Heard, M S; Dewar, A M; Perry, J N; Squire, G R

    2006-03-22

    The Farm Scale Evaluations (FSEs) showed that genetically modified herbicide-tolerant (GMHT) cropping systems could influence farmland biodiversity because of their effects on weed biomass and seed production. Recently published results for winter oilseed rape showed that a switch to GMHT crops significantly affected weed seedbanks for at least 2 years after the crops were sown, potentially causing longer-term effects on other taxa. Here, we seek evidence for similar medium-term effects on weed seedbanks following spring-sown GMHT crops, using newly available data from the FSEs. Weed seedbanks following GMHT maize were significantly higher than following conventional varieties for both the first and second years, while by contrast, seedbanks following GMHT spring oilseed rape were significantly lower over this period. Seedbanks following GMHT beet were smaller than following conventional crops in the first year after the crops had been sown, but this difference was much reduced by the second year for reasons that are not clear. These new data provide important empirical evidence for longer-term effects of GMHT cropping on farmland biodiversity.

  11. Tempest in a tea pot: How did the public conversation on genetically modified crops drift so far from the facts?

    PubMed

    Goldstein, Daniel A

    2014-06-01

    The debate over genetically modified (GM) crops has raged in Europe since 1996, but had barely risen above a whisper in the USA until recent labeling debates raised public attention. This article will explain GM crops and traits discuss safety assessment provide a view on safety from authoritative organizations discuss selected issues of current debate, and provide the author's perspective as to why the public debate has drifted so far from scientific reality. The economic and environmental benefits of GM crops are beyond scope, but references are provided. GM food and feed undergo comprehensive assessments using recognized approaches to assure they are as safe as the conventional congener. Issues of food safety and nutrition, unrelated to the GM process, may arise when GM foods display novel components or composition. Unanticipated genetic effects in GM crops appear to be limited in contrast to existing variations among conventional varieties resulting from breeding, mutation, and natural mobile genetic elements. Allergenic potential is assessed when selecting genes for introduction into GM crops and remains a theoretical risk to date. Emerging weed and insect resistance is not unique to GM technology and will require the use of integrated pest management/best practices for pest control. Gene flow from GM crops to wild relatives is limited by existing biological barriers but can at time be a relevant consideration in gene selection and planting practices. Insect-resistant GM crops have significantly reduced use of chemical insecticides and appear to have reduced the incidence of pesticide poisoning in areas where small scale farming and hand application are common. Changes in herbicide patterns are more complex and are evolving over time in response to weed resistance management needs. Recent public debate is driven by a combination of unfounded allegations about the technology and purveyors, pseudoscience, and attempts to apply a strict precautionary principle.

  12. Bringing policy relevance and scientific discipline to environmental risk assessment for genetically modified crops.

    PubMed

    Herman, Rod A; Garcia-Alonso, Monica; Layton, Raymond; Raybould, Alan

    2013-09-01

    Although public opinion is important in deciding what is valued by society, governments have determined that scientific expertise is required to evaluate potential environmental effects of genetically modified (GM) crops. We suggest how to evaluate rigorously the environmental effects of GM crops in the context of a scientific investigation. Following a disciplined scientific approach to environmental risk assessment (ERA) for GM crops should help resolve controversy in identifying and addressing risk.

  13. Comparative impact of genetically modified and non modified maize (Zea mays L.) on succeeding crop and associated weed.

    PubMed

    Ibrahim, Muhammad; Ahmed, Naseer; Ullah, Faizan; Shinwari, Zabta Khan; Bano, Asghari

    2016-04-01

    This research work documents the comparative impact of genetically modified (GM) (insect resistance) and non modified maize (Zea mays L.) on growth and germination of succeeding crop wheat (Triticum aestivum L.) and associated weed (Avena fatua L.). The aqueous extracts of both the GM and non-GM maize exhibited higher phenolic content than that of methanolic extracts. Germination percentage and germination index of wheat was significantly decreased by GM methanolic extract (10%) as well as that of non-GM maize at 3% aqueous extract. Similarly germination percentage of weed (Avena fatua L.) was significantly reduced by application of 3% and 5% methanolic GM extracts. All extracts of GM maize showed non-significant effect on the number of roots, root length and shoot length per plant but 5% and 10% methanolic extracts of non-GM maize significantly increased the number of roots per plant of wheat seedling. Similarly, 10% methanolic extract of GM maize significantly increased the number of roots per plant of weed seedling. Methanolic extracts of GM and non-GM maize (3% and 5%) significantly decreased the protease activity in wheat as compared to untreated control.

  14. Insect-resistant biotech crops and their impacts on beneficial arthropods.

    PubMed

    Gatehouse, A M R; Ferry, N; Edwards, M G; Bell, H A

    2011-05-12

    With a projected population of 10 billion by 2050, an immediate priority for agriculture is to achieve increased crop yields in a sustainable and cost-effective way. The concept of using a transgenic approach was realized in the mid-1990s with the commercial introduction of genetically modified (GM) crops. By 2010, the global value of the seed alone was US $11.2 billion, with commercial biotech maize, soya bean grain and cotton valued at approximately US $150 billion. In recent years, it has become evident that insect-resistant crops expressing δ-endotoxin genes from Bacillus thuringiensis have made a significant beneficial impact on global agriculture, not least in terms of pest reduction and improved quality. However, because of the potential for pest populations to evolve resistance, and owing to lack of effective control of homopteran pests, alternative strategies are being developed. Some of these are based on Bacillus spp. or other insect pathogens, while others are based on the use of plant- and animal-derived genes. However, if such approaches are to play a useful role in crop protection, it is desirable that they do not have a negative impact on beneficial organisms at higher trophic levels thus affecting the functioning of the agro-ecosystem. This widely held concern over the ecological impacts of GM crops has led to the extensive examination of the potential effects of a range of transgene proteins on non-target and beneficial insects. The findings to date with respect to both commercial and experimental GM crops expressing anti-insect genes are discussed here, with particular emphasis on insect predators and parasitoids.

  15. Insect-resistant biotech crops and their impacts on beneficial arthropods

    PubMed Central

    Gatehouse, A. M. R.; Ferry, N.; Edwards, M. G.; Bell, H. A.

    2011-01-01

    With a projected population of 10 billion by 2050, an immediate priority for agriculture is to achieve increased crop yields in a sustainable and cost-effective way. The concept of using a transgenic approach was realized in the mid-1990s with the commercial introduction of genetically modified (GM) crops. By 2010, the global value of the seed alone was US $11.2 billion, with commercial biotech maize, soya bean grain and cotton valued at approximately US $150 billion. In recent years, it has become evident that insect-resistant crops expressing δ-endotoxin genes from Bacillus thuringiensis have made a significant beneficial impact on global agriculture, not least in terms of pest reduction and improved quality. However, because of the potential for pest populations to evolve resistance, and owing to lack of effective control of homopteran pests, alternative strategies are being developed. Some of these are based on Bacillus spp. or other insect pathogens, while others are based on the use of plant- and animal-derived genes. However, if such approaches are to play a useful role in crop protection, it is desirable that they do not have a negative impact on beneficial organisms at higher trophic levels thus affecting the functioning of the agro-ecosystem. This widely held concern over the ecological impacts of GM crops has led to the extensive examination of the potential effects of a range of transgene proteins on non-target and beneficial insects. The findings to date with respect to both commercial and experimental GM crops expressing anti-insect genes are discussed here, with particular emphasis on insect predators and parasitoids. PMID:21444317

  16. Spatiotemporal patterns of non-genetically modified crops in the era of expansion of genetically modified food.

    PubMed

    Sun, Jing; Wu, Wenbin; Tang, Huajun; Liu, Jianguo

    2015-09-18

    Despite heated debates over the safety of genetically modified (GM) food, GM crops have been expanding rapidly. Much research has focused on the expansion of GM crops. However, the spatiotemporal dynamics of non-genetically modified (non-GM) crops are not clear, although they may have significant environmental and agronomic impacts and important policy implications. To understand the dynamics of non-GM crops and to inform the debates among relevant stakeholders, we conducted spatiotemporal analyses of China's major non-GM soybean production region, the Heilongjiang Province. Even though the total soybean planting area decreased from 2005 to 2010, surprisingly, there were hotspots of increase. The results also showed hotspots of loss as well as a large decline in the number and continuity of soybean plots. Since China is the largest non-GM soybean producer in the world, the decline of its major production region may signal the continual decline of global non-GM soybeans.

  17. Spatiotemporal patterns of non-genetically modified crops in the era of expansion of genetically modified food

    PubMed Central

    Sun, Jing; Wu, Wenbin; Tang, Huajun; Liu, Jianguo

    2015-01-01

    Despite heated debates over the safety of genetically modified (GM) food, GM crops have been expanding rapidly. Much research has focused on the expansion of GM crops. However, the spatiotemporal dynamics of non-genetically modified (non-GM) crops are not clear, although they may have significant environmental and agronomic impacts and important policy implications. To understand the dynamics of non-GM crops and to inform the debates among relevant stakeholders, we conducted spatiotemporal analyses of China’s major non-GM soybean production region, the Heilongjiang Province. Even though the total soybean planting area decreased from 2005 to 2010, surprisingly, there were hotspots of increase. The results also showed hotspots of loss as well as a large decline in the number and continuity of soybean plots. Since China is the largest non-GM soybean producer in the world, the decline of its major production region may signal the continual decline of global non-GM soybeans. PMID:26380899

  18. Crop management and agronomic context of the Farm Scale Evaluations of genetically modified herbicide-tolerant crops.

    PubMed Central

    Champion, G T; May, M J; Bennett, S; Brooks, D R; Clark, S J; Daniels, R E; Firbank, L G; Haughton, A J; Hawes, C; Heard, M S; Perry, J N; Randle, Z; Rossall, M J; Rothery, P; Skellern, M P; Scott, R J; Squire, G R; Thomas, M R

    2003-01-01

    The Farm Scale Evaluations of genetically modified herbicide-tolerant crops (GMHT) were conducted in the UK from 2000 to 2002 on beet (sugar and fodder), spring oilseed rape and forage maize. The management of the crops studied is described and compared with current conventional commercial practice. The distribution of field sites adequately represented the areas currently growing these crops, and the sample contained sites operated at a range of management intensities, including low intensity. Herbicide inputs were audited, and the active ingredients used and the rates and the timings of applications compared well with current practice for both GMHT and conventional crops. Inputs on sugar beet were lower than, and inputs on spring oilseed rape and forage maize were consistent with, national averages. Regression analysis of herbicide-application strategies and weed emergence showed that inputs applied by farmers increased with weed densities in beet and forage maize. GMHT crops generally received only one herbicide active ingredient per crop, later and fewer herbicide sprays and less active ingredient (for beet and maize) than the conventional treatments. The audit of inputs found no evidence of bias. PMID:14561315

  19. Glyphosate Effects on Plant Mineral Nutrition, Crop Rhizosphere Microbiota, and Plant Disease in Glyphosate-Resistant Crops

    PubMed Central

    2012-01-01

    Claims have been made recently that glyphosate-resistant (GR) crops sometimes have mineral deficiencies and increased plant disease. This review evaluates the literature that is germane to these claims. Our conclusions are: (1) although there is conflicting literature on the effects of glyphosate on mineral nutrition on GR crops, most of the literature indicates that mineral nutrition in GR crops is not affected by either the GR trait or by application of glyphosate; (2) most of the available data support the view that neither the GR transgenes nor glyphosate use in GR crops increases crop disease; and (3) yield data on GR crops do not support the hypotheses that there are substantive mineral nutrition or disease problems that are specific to GR crops. PMID:23013354

  20. Benefits of genetically modified crops for the poor: household income, nutrition, and health.

    PubMed

    Qaim, Matin

    2010-11-30

    The potential impacts of genetically modified (GM) crops on income, poverty and nutrition in developing countries continue to be the subject of public controversy. Here, a review of the evidence is given. As an example of a first-generation GM technology, the effects of insect-resistant Bt cotton are analysed. Bt cotton has already been adopted by millions of small-scale farmers, in India, China, and South Africa among others. On average, farmers benefit from insecticide savings, higher effective yields and sizeable income gains. Insights from India suggest that Bt cotton is employment generating and poverty reducing. As an example of a second-generation technology, the likely impacts of beta-carotene-rich Golden Rice are analysed from an ex ante perspective. Vitamin A deficiency is a serious nutritional problem, causing multiple adverse health outcomes. Simulations for India show that Golden Rice could reduce related health problems significantly, preventing up to 40,000 child deaths every year. These examples clearly demonstrate that GM crops can contribute to poverty reduction and food security in developing countries. To realise such social benefits on a larger scale requires more public support for research targeted to the poor, as well as more efficient regulatory and technology delivery systems.

  1. Molecular basis for the herbicide resistance of Roundup Ready crops.

    PubMed

    Funke, Todd; Han, Huijong; Healy-Fried, Martha L; Fischer, Markus; Schönbrunn, Ernst

    2006-08-29

    The engineering of transgenic crops resistant to the broad-spectrum herbicide glyphosate has greatly improved agricultural efficiency worldwide. Glyphosate-based herbicides, such as Roundup, target the shikimate pathway enzyme 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase, the functionality of which is absolutely required for the survival of plants. Roundup Ready plants carry the gene coding for a glyphosate-insensitive form of this enzyme, obtained from Agrobacterium sp. strain CP4. Once incorporated into the plant genome, the gene product, CP4 EPSP synthase, confers crop resistance to glyphosate. Although widely used, the molecular basis for this glyphosate-resistance has remained obscure. We generated a synthetic gene coding for CP4 EPSP synthase and characterized the enzyme using kinetics and crystallography. The CP4 enzyme has unexpected kinetic and structural properties that render it unique among the known EPSP synthases. Glyphosate binds to the CP4 EPSP synthase in a condensed, noninhibitory conformation. Glyphosate sensitivity can be restored through a single-site mutation in the active site (Ala-100-Gly), allowing glyphosate to bind in its extended, inhibitory conformation.

  2. Glyphosate effects on plant mineral nutrition, crop rhizosphere microbiota, and plant disease in glyphosate-resistant crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There have been recent claims that glyphosate-resistant (GR) crops sometimes have mineral deficiencies. Claimed deficiencies, such as with Mn, have been linked to alleged increases in plant disease in GR crops. This review evaluates the literature that is germane to these claims. Our conclusions a...

  3. Safety assessment of foods from genetically modified crops in countries with developing economies.

    PubMed

    Delaney, Bryan

    2015-12-01

    Population growth particularly in countries with developing economies will result in a need to increase food production by 70% by the year 2050. Biotechnology has been utilized to produce genetically modified (GM) crops for insect and weed control with benefits including increased crop yield and will also be used in emerging countries. A multicomponent safety assessment paradigm has been applied to individual GM crops to determine whether they as safe as foods from non-GM crops. This paper reviews methods to assess the safety of foods from GM crops for safe consumption from the first generation of GM crops. The methods can readily be applied to new products developed within country and this paper will emphasize the concept of data portability; that safety data produced in one geographic location is suitable for safety assessment regardless of where it is utilized.

  4. Multiplex PCR-based simultaneous amplification of selectable marker and reporter genes for the screening of genetically modified crops.

    PubMed

    Randhawa, Gurinder Jit; Chhabra, Rashmi; Singh, Monika

    2009-06-24

    The development and commercialization of genetically modified (GM) crops with enhanced insect and herbicide resistance, abiotic stress tolerance, and improved nutritional quality has expanded dramatically. Notwithstanding the huge potential benefits of GM crops, the perceived environmental risks associated with these crops need to be addressed in proper perspective. One critical concern is the adventitious presence or unintentional mixing of GM seed in non-GM seed lots, which can seriously affect the global seed market. It would therefore be necessary though a challenging task to develop reliable, efficient, and economical assays for GM detection, identification, and quantification in non-GM seed lots. This can be systematically undertaken by preliminary screening for control elements and selectable or scorable (reporter) marker genes. In this study, simplex and multiplex polymerase chain reaction (PCR) assays individually as well as simultaneously amplifying the commonly used selectable marker genes, i.e., aadA, bar, hpt, nptII, pat encoding, respectively, for aminoglycoside-3'-adenyltransferase, Streptococcus viridochromogenes phosphinothricin-N-acetyltransferase, hygromycin phosphotransferase, neomycin phosphotransferase, Streptococcus hygroscopicus phosphinothricin-N-acetyltransferase, and a reporter gene uidA encoding beta-d-glucuronidase, were developed as a reliable tool for qualitative screening of GM crops. The efficiency of the assays was also standardized in the test samples prepared by artificial mixing of transgenic seed samples in different proportions. The developed multiplex PCR assays will be useful in verifying the GM status of a sample irrespective of the crop and GM trait.

  5. Gene flow from herbicide-resistant crops: it's not just for transgenes.

    PubMed

    Mallory-Smith, Carol A; Sanchez Olguin, Elena

    2011-06-08

    Gene flow was raised as one of the first issues related to the development and release of genetically engineered (GE) crops. Gene flow has remained a topic of discussion for more than 20 years and is still used as an argument against the release of transgenic crops. With respect to herbicide-resistant crops, gene flow does not differ whether the herbicide resistance trait is introduced via genetic engineering or via conventional breeding techniques. Conventional breeding and genetic engineering techniques have been used to produce herbicide resistance in many of the same crop species. In addition, conventional breeding has been used to produce a broader range of herbicide-resistant crops than have been genetically engineered for herbicide resistance. Economic, political, and social concerns center on the breeding technique, but the results of gene flow for weed management are the same irrespective of breeding technique. This paper will focus on gene flow from nonGE herbicide-resistant crops in North America.

  6. Genetic engineering of crop plants for fungal resistance: role of antifungal genes.

    PubMed

    Ceasar, S Antony; Ignacimuthu, S

    2012-06-01

    Fungal diseases damage crop plants and affect agricultural production. Transgenic plants have been produced by inserting antifungal genes to confer resistance against fungal pathogens. Genes of fungal cell wall-degrading enzymes, such as chitinase and glucanase, are frequently used to produce fungal-resistant transgenic crop plants. In this review, we summarize the details of various transformation studies to develop fungal resistance in crop plants.

  7. Biotech/GM crops in horticulture: plum cv. HoneySweet resistant to plum pox virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Commercialization of Biotech crops started in 1995. By 2011, genetically modified (GM) crops were grown world-wide on 160 million ha. Only 114.507 ha of GM crops were grown in Europe, of that, 114.490 ha were Bt maize and 17 ha were potato for industrial starch production. Currently, developing c...

  8. Sensitive dependencies and separation distances for genetically modified herbicide-tolerant crops.

    PubMed Central

    Perry, Joe N

    2002-01-01

    The amount of land available for the coexistent growing of both organic and genetically modified herbicide-tolerant (GMHT) crops depends on the separation distance between the two types of crop. The form of the decline in the proportion of land available for growing one of these crop types due to increasing separation distance is linear on a suitable scale, but with a slope and intercept that are sensitively dependent on the proportion of the other crop already present. Spatially explicit simulations from realistic scenarios indicate that a major increase in separation distances, currently under review by the UK government, may have serious implications for the future coexistence of organic and GMHT crops in the UK. PMID:12061962

  9. Africa's inevitable walk to genetically modified (GM) crops: opportunities and challenges for commercialization.

    PubMed

    Okeno, James A; Wolt, Jeffrey D; Misra, Manjit K; Rodriguez, Lulu

    2013-01-25

    High relative poverty levels in Africa are attributed to the continent's under performing agriculture. Drought, low-yielding crop varieties, pests and diseases, poor soils, low fertilizer use, limited irrigation and lack of modern technologies are among the problems that plague African agriculture. Genetically modified (GM) crops may possess attributes that can help overcome some of these constraints, but have yet to be fully embraced in the mix of technology solutions for African agriculture. Cognizant of this, South Africa, Burkina Faso and Egypt are steadily growing GM crops on a commercial scale. Countries like Kenya, Nigeria, and Uganda are increasingly field-testing these crops with the view to commercialize them. These countries show strong government support for GM technology. Progress by these first adopter nations provides an insight as to how GM crops are increasingly being viewed as one of the ways in which the continent can invigorate the agriculture sector and achieve food security.

  10. Grafting: A Technique to Modify Ion Accumulation in Horticultural Crops

    PubMed Central

    Nawaz, Muhammad A.; Imtiaz, Muhammad; Kong, Qiusheng; Cheng, Fei; Ahmed, Waqar; Huang, Yuan; Bie, Zhilong

    2016-01-01

    Grafting is a centuries-old technique used in plants to obtain economic benefits. Grafting increases nutrient uptake and utilization efficiency in a number of plant species, including fruits, vegetables, and ornamentals. Selected rootstocks of the same species or close relatives are utilized in grafting. Rootstocks absorb more water and ions than self-rooted plants and transport these water and ions to the aboveground scion. Ion uptake is regulated by a complex communication mechanism between the scion and rootstock. Sugars, hormones, and miRNAs function as long-distance signaling molecules and regulate ion uptake and ion homeostasis by affecting the activity of ion transporters. This review summarizes available information on the effect of rootstock on nutrient uptake and utilization and the mechanisms involved. Information on specific nutrient-efficient rootstocks for different crops of commercial importance is also provided. Several other important approaches, such as interstocking (during double grafting), inarching, use of plant-growth-promoting rhizobacteria, use of arbuscular mycorrhizal fungi, use of plant growth substances (e.g., auxin and melatonin), and use of genetically engineered rootstocks and scions (transgrafting), are highlighted; these approaches can be combined with grafting to enhance nutrient uptake and utilization in commercially important plant species. Whether the rootstock and scion affect each other's soil microbiota and their effect on the nutrient absorption of rootstocks remain largely unknown. Similarly, the physiological and molecular bases of grafting, crease formation, and incompatibility are not fully identified and require investigation. Grafting in horticultural crops can help reveal the basic biology of grafting, the reasons for incompatibility, sensing, and signaling of nutrients, ion uptake and transport, and the mechanism of heavy metal accumulation and restriction in rootstocks. Ion transporter and miRNA-regulated nutrient

  11. Grafting: A Technique to Modify Ion Accumulation in Horticultural Crops.

    PubMed

    Nawaz, Muhammad A; Imtiaz, Muhammad; Kong, Qiusheng; Cheng, Fei; Ahmed, Waqar; Huang, Yuan; Bie, Zhilong

    2016-01-01

    Grafting is a centuries-old technique used in plants to obtain economic benefits. Grafting increases nutrient uptake and utilization efficiency in a number of plant species, including fruits, vegetables, and ornamentals. Selected rootstocks of the same species or close relatives are utilized in grafting. Rootstocks absorb more water and ions than self-rooted plants and transport these water and ions to the aboveground scion. Ion uptake is regulated by a complex communication mechanism between the scion and rootstock. Sugars, hormones, and miRNAs function as long-distance signaling molecules and regulate ion uptake and ion homeostasis by affecting the activity of ion transporters. This review summarizes available information on the effect of rootstock on nutrient uptake and utilization and the mechanisms involved. Information on specific nutrient-efficient rootstocks for different crops of commercial importance is also provided. Several other important approaches, such as interstocking (during double grafting), inarching, use of plant-growth-promoting rhizobacteria, use of arbuscular mycorrhizal fungi, use of plant growth substances (e.g., auxin and melatonin), and use of genetically engineered rootstocks and scions (transgrafting), are highlighted; these approaches can be combined with grafting to enhance nutrient uptake and utilization in commercially important plant species. Whether the rootstock and scion affect each other's soil microbiota and their effect on the nutrient absorption of rootstocks remain largely unknown. Similarly, the physiological and molecular bases of grafting, crease formation, and incompatibility are not fully identified and require investigation. Grafting in horticultural crops can help reveal the basic biology of grafting, the reasons for incompatibility, sensing, and signaling of nutrients, ion uptake and transport, and the mechanism of heavy metal accumulation and restriction in rootstocks. Ion transporter and miRNA-regulated nutrient

  12. Attitudes of Agricultural Experts Toward Genetically Modified Crops: A Case Study in Southwest Iran.

    PubMed

    Ghanian, Mansour; Ghoochani, Omid M; Kitterlin, Miranda; Jahangiry, Sheida; Zarafshani, Kiumars; Van Passel, Steven; Azadi, Hossein

    2016-04-01

    The production of genetically modified (GM) crops is growing around the world, and with it possible opportunities to combat food insecurity and hunger, as well as solutions to current problems facing conventional agriculture. In this regard the use of GMOs in food and agricultural applications has increased greatly over the past decade. However, the development of GM crops has been a matter of considerable interest and worldwide public controversy. This, in addition to skepticism, has stifled the use of this practice on a large scale in many areas, including Iran. It stands to reason that a greater understanding of this practice could be formed after a review of the existing expert opinions surrounding GM crops. Therefore, the purpose of this study was to analyze the predictors that influence agricultural experts' attitudes toward the development of and policies related to GM crops. Using a descriptive correlational research method, questionnaire data was collected from 65 experts from the Agricultural Organization in the Gotvand district in Southwest Iran. Results indicated that agricultural experts were aware of the environmental benefits and possible risks associated with GM crops. The majority of participants agreed that GM crops could improve food security and accelerate rural development, and were proponents of labeling practices for GM crops. Finally, there was a positive correlation between the perception of benefits and attitudes towards GM crops.

  13. Small RNA Based Genetic Engineering for Plant Viral Resistance: Application in Crop Protection

    PubMed Central

    Khalid, Annum; Zhang, Qingling; Yasir, Muhammad; Li, Feng

    2017-01-01

    Small RNAs regulate a large set of gene expression in all plants and constitute a natural immunity against viruses. Small RNA based genetic engineering (SRGE) technology had been explored for crop protection against viruses for nearly 30 years. Viral resistance has been developed in diverse crops with SRGE technology and a few viral resistant crops have been approved for commercial release. In this review we summarized the efforts generating viral resistance with SRGE in different crops, analyzed the evolution of the technology, its efficacy in different crops for different viruses and its application status in different crops. The challenge and potential solution for application of SRGE in crop protection are also discussed. PMID:28167936

  14. Innovative farmers and regulatory gatekeepers: Genetically modified crops regulation and adoption in developing countries

    PubMed Central

    Sinebo, Woldeyesus; Maredia, Karim

    2016-01-01

    ABSTRACT The regulation of genetically modified (GM) crops is a topical issue in agriculture and environment over the past 2 decades. The objective of this paper is to recount regulatory and adoption practices in some developing countries that have successfully adopted GM crops so that aspiring countries may draw useful lessons and best practices for their biosafatey regulatory regimes. The first 11 mega-GM crops growing countries each with an area of more than one million hectares in 2014 were examined. Only five out of the 11 countries had smooth and orderly adoption of these crops as per the regulatory requirement of each country. In the remaining 6 countries (all developing countries), GM crops were either introduced across borders without official authorization, released prior to regulatory approval or unapproved seeds were sold along with the approved ones in violation to the existing regulations. Rapid expansion of transgenic crops over the past 2 decades in the developing world was a result of an intense desire by farmers to adopt these crops irrespective of regulatory roadblocks. Lack of workable biosafety regulatory system and political will to support GM crops encouraged unauthorized access to GM crop varieties. In certain cases, unregulated access in turn appeared to result in the adoption of substandard or spurious technology which undermined performance and productivity. An optimal interaction among the national agricultural innovation systems, biosafety regulatory bodies, biotech companies and high level policy makers is vital in making a workable regulated progress in the adoption of GM crops. Factoring forgone opportunities to farmers to benefit from GM crops arising from overregulation into biosafety risk analysis and decision making is suggested. Building functional biosafety regulatory systems that balances the needs of farmers to access and utilize the GM technology with the regulatory imperatives to ensure adequate safety to the environment

  15. Innovative farmers and regulatory gatekeepers: Genetically modified crops regulation and adoption in developing countries.

    PubMed

    Sinebo, Woldeyesus; Maredia, Karim

    2016-01-02

    The regulation of genetically modified (GM) crops is a topical issue in agriculture and environment over the past 2 decades. The objective of this paper is to recount regulatory and adoption practices in some developing countries that have successfully adopted GM crops so that aspiring countries may draw useful lessons and best practices for their biosafatey regulatory regimes. The first 11 mega-GM crops growing countries each with an area of more than one million hectares in 2014 were examined. Only five out of the 11 countries had smooth and orderly adoption of these crops as per the regulatory requirement of each country. In the remaining 6 countries (all developing countries), GM crops were either introduced across borders without official authorization, released prior to regulatory approval or unapproved seeds were sold along with the approved ones in violation to the existing regulations. Rapid expansion of transgenic crops over the past 2 decades in the developing world was a result of an intense desire by farmers to adopt these crops irrespective of regulatory roadblocks. Lack of workable biosafety regulatory system and political will to support GM crops encouraged unauthorized access to GM crop varieties. In certain cases, unregulated access in turn appeared to result in the adoption of substandard or spurious technology which undermined performance and productivity. An optimal interaction among the national agricultural innovation systems, biosafety regulatory bodies, biotech companies and high level policy makers is vital in making a workable regulated progress in the adoption of GM crops. Factoring forgone opportunities to farmers to benefit from GM crops arising from overregulation into biosafety risk analysis and decision making is suggested. Building functional biosafety regulatory systems that balances the needs of farmers to access and utilize the GM technology with the regulatory imperatives to ensure adequate safety to the environment and human

  16. Assessment of the safety of foods derived from genetically modified (GM) crops.

    PubMed

    König, A; Cockburn, A; Crevel, R W R; Debruyne, E; Grafstroem, R; Hammerling, U; Kimber, I; Knudsen, I; Kuiper, H A; Peijnenburg, A A C M; Penninks, A H; Poulsen, M; Schauzu, M; Wal, J M

    2004-07-01

    This paper provides guidance on how to assess the safety of foods derived from genetically modified crops (GM crops); it summarises conclusions and recommendations of Working Group 1 of the ENTRANSFOOD project. The paper provides an approach for adapting the test strategy to the characteristics of the modified crop and the introduced trait, and assessing potential unintended effects from the genetic modification. The proposed approach to safety assessment starts with the comparison of the new GM crop with a traditional counterpart that is generally accepted as safe based on a history of human food use (the concept of substantial equivalence). This case-focused approach ensures that foods derived from GM crops that have passed this extensive test-regime are as safe and nutritious as currently consumed plant-derived foods. The approach is suitable for current and future GM crops with more complex modifications. First, the paper reviews test methods developed for the risk assessment of chemicals, including food additives and pesticides, discussing which of these methods are suitable for the assessment of recombinant proteins and whole foods. Second, the paper presents a systematic approach to combine test methods for the safety assessment of foods derived from a specific GM crop. Third, the paper provides an overview on developments in this area that may prove of use in the safety assessment of GM crops, and recommendations for research priorities. It is concluded that the combination of existing test methods provides a sound test-regime to assess the safety of GM crops. Advances in our understanding of molecular biology, biochemistry, and nutrition may in future allow further improvement of test methods that will over time render the safety assessment of foods even more effective and informative.

  17. Real-time PCR array as a universal platform for the detection of genetically modified crops and its application in identifying unapproved genetically modified crops in Japan.

    PubMed

    Mano, Junichi; Shigemitsu, Natsuki; Futo, Satoshi; Akiyama, Hiroshi; Teshima, Reiko; Hino, Akihiro; Furui, Satoshi; Kitta, Kazumi

    2009-01-14

    We developed a novel type of real-time polymerase chain reaction (PCR) array with TaqMan chemistry as a platform for the comprehensive and semiquantitative detection of genetically modified (GM) crops. Thirty primer-probe sets for the specific detection of GM lines, recombinant DNA (r-DNA) segments, endogenous reference genes, and donor organisms were synthesized, and a 96-well PCR plate was prepared with a different primer-probe in each well as the real-time PCR array. The specificity and sensitivity of the array were evaluated. A comparative analysis with the data and publicly available information on GM crops approved in Japan allowed us to assume the possibility of unapproved GM crop contamination. Furthermore, we designed a Microsoft Excel spreadsheet application, Unapproved GMO Checker version 2.01, which helps process all the data of real-time PCR arrays for the easy assumption of unapproved GM crop contamination. The spreadsheet is available free of charge at http://cse.naro.affrc.go.jp/jmano/index.html .

  18. Genetically modified crops for the bioeconomy: meeting public and regulatory expectations.

    PubMed

    Chapotin, Saharah Moon; Wolt, Jeffrey D

    2007-12-01

    As the United States moves toward a plant-based bioeconomy, a large research and development effort is focused on creating new feedstocks to meet biomass demand for biofuels, bioenergy, and specialized bioproducts, such as industrial compounds and biomaterial precursors. Most bioeconomy projections assume the widespread deployment of novel feedstocks developed through the use of modern molecular breeding techniques, but rarely consider the challenges involved with the use of genetically modified crops, which can include hurdles due to regulatory approvals, market adoption, and public acceptance. In this paper we consider the implications of various transgenic crops and traits under development for the bioeconomy that highlight these challenges. We believe that an awareness of the issues in crop and trait selection will allow developers to design crops with maximum stakeholder appeal and with the greatest potential for widespread adoption, while avoiding applications unlikely to meet regulatory approval or gain market and public acceptance.

  19. Genetically Modified Crops and Nuisance: Exploring the Role of Precaution in Private Law

    ERIC Educational Resources Information Center

    Craik, Neil; Culver, Keith; Siebrasse, Norman

    2007-01-01

    This article critically considers calls for the precautionary principle to inform judicial decision making in a private law context in light of the Hoffman litigation, where it is alleged that the potential for genetic contamination from genetically modified (GM) crops causes an unreasonable interference with the rights of organic farmers to use…

  20. Status of market, regulation and research of genetically modified crops in Chile.

    PubMed

    Sánchez, Miguel A; León, Gabriel

    2016-12-25

    Agricultural biotechnology and genetically modified (GM) crops are effective tools to substantially increase productivity, quality, and environmental sustainability in agricultural farming. Furthermore, they may contribute to improving the nutritional content of crops, addressing needs related to public health. Chile has become one of the most important global players for GM seed production for counter-season markets and research purposes. It has a comprehensive regulatory framework to carry out this activity, while at the same time there are numerous regulations from different agencies addressing several aspects related to GM crops. Despite imports of GM food/feed or ingredients for the food industry being allowed without restrictions, Chilean farmers are not using GM seeds for farming purposes because of a lack of clear guidelines. Chile is in a rather contradictory situation about GM crops. The country has invested considerable resources to fund research and development on GM crops, but the lack of clarity in the current regulatory situation precludes the use of such research to develop new products for Chilean farmers. Meanwhile, a larger scientific capacity regarding GM crop research continues to build up in the country. The present study maps and analyses the current regulatory environment for research and production of GM crops in Chile, providing an updated overview of the current status of GM seeds production, research and regulatory issues.

  1. Perspectives on transgenic, herbicide-resistant crops in the United States almost 20 years after introduction.

    PubMed

    Duke, Stephen O

    2015-05-01

    Herbicide-resistant crops have had a profound impact on weed management. Most of the impact has been by glyphosate-resistant maize, cotton, soybean and canola. Significant economic savings, yield increases and more efficacious and simplified weed management have resulted in widespread adoption of the technology. Initially, glyphosate-resistant crops enabled significantly reduced tillage and reduced the environmental impact of weed management. Continuous use of glyphosate with glyphosate-resistant crops over broad areas facilitated the evolution of glyphosate-resistant weeds, which have resulted in increases in the use of tillage and other herbicides with glyphosate, reducing some of the initial environmental benefits of glyphosate-resistant crops. Transgenic crops with resistance to auxinic herbicides, as well as to herbicides that inhibit acetolactate synthase, acetyl-CoA carboxylase and hydroxyphenylpyruvate dioxygenase, stacked with glyphosate and/or glufosinate resistance, will become available in the next few years. These technologies will provide additional weed management options for farmers, but will not have all of the positive effects (reduced cost, simplified weed management, lowered environmental impact and reduced tillage) that glyphosate-resistant crops had initially. In the more distant future, other herbicide-resistant crops (including non-transgenic ones), herbicides with new modes of action and technologies that are currently in their infancy (e.g. bioherbicides, sprayable herbicidal RNAi and/or robotic weeding) may affect the role of transgenic, herbicide-resistant crops in weed management. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  2. Herbicide resistance and biodiversity: agronomic and environmental aspects of genetically modified herbicide-resistant plants.

    PubMed

    Schütte, Gesine; Eckerstorfer, Michael; Rastelli, Valentina; Reichenbecher, Wolfram; Restrepo-Vassalli, Sara; Ruohonen-Lehto, Marja; Saucy, Anne-Gabrielle Wuest; Mertens, Martha

    2017-01-01

    Farmland biodiversity is an important characteristic when assessing sustainability of agricultural practices and is of major international concern. Scientific data indicate that agricultural intensification and pesticide use are among the main drivers of biodiversity loss. The analysed data and experiences do not support statements that herbicide-resistant crops provide consistently better yields than conventional crops or reduce herbicide amounts. They rather show that the adoption of herbicide-resistant crops impacts agronomy, agricultural practice, and weed management and contributes to biodiversity loss in several ways: (i) many studies show that glyphosate-based herbicides, which were commonly regarded as less harmful, are toxic to a range of aquatic organisms and adversely affect the soil and intestinal microflora and plant disease resistance; the increased use of 2,4-D or dicamba, linked to new herbicide-resistant crops, causes special concerns. (ii) The adoption of herbicide-resistant crops has reduced crop rotation and favoured weed management that is solely based on the use of herbicides. (iii) Continuous herbicide resistance cropping and the intensive use of glyphosate over the last 20 years have led to the appearance of at least 34 glyphosate-resistant weed species worldwide. Although recommended for many years, farmers did not counter resistance development in weeds by integrated weed management, but continued to rely on herbicides as sole measure. Despite occurrence of widespread resistance in weeds to other herbicides, industry rather develops transgenic crops with additional herbicide resistance genes. (iv) Agricultural management based on broad-spectrum herbicides as in herbicide-resistant crops further decreases diversity and abundance of wild plants and impacts arthropod fauna and other farmland animals. Taken together, adverse impacts of herbicide-resistant crops on biodiversity, when widely adopted, should be expected and are indeed very hard

  3. A novel approach to the use of genetically modified herbicide tolerant crops for environmental benefit.

    PubMed Central

    Dewar, Alan M; May, Mike J; Woiwod, Ian P; Haylock, Lisa A; Champion, Gillian T; Garner, Beulah H; Sands, Richard J N; Qi, Aiming; Pidgeon, John D

    2003-01-01

    The proposed introduction of genetically modified herbicide tolerant (GMHT) crops, with claims of improved weed control, has prompted fears about possible environmental impacts of their widespread adoption, particularly on arable weeds, insects and associated farmland birds. In response to this, we have developed a novel weed-management system for GMHT sugar beet, based on band spraying, which exploits the flexibility offered by the broad-spectrum partner herbicides. Here, we show the results from two series of field experiments which, taken together, demonstrate that, by using this system, crops can be managed for enhanced weed and insect biomass without compromising yield, thus potentially offering food and shelter to farmland birds and other wildlife. These results could be applicable widely to other row crops, and indicate that creative use of GMHT technology could be a powerful tool for developing more sustainable farming systems in the future. PMID:12639311

  4. Unintended compositional changes in genetically modified (GM) crops: 20 years of research.

    PubMed

    Herman, Rod A; Price, William D

    2013-12-04

    The compositional equivalency between genetically modified (GM) crops and nontransgenic comparators has been a fundamental component of human health safety assessment for 20 years. During this time, a large amount of information has been amassed on the compositional changes that accompany both the transgenesis process and traditional breeding methods; additionally, the genetic mechanisms behind these changes have been elucidated. After two decades, scientists are encouraged to objectively assess this body of literature and determine if sufficient scientific uncertainty still exists to continue the general requirement for these studies to support the safety assessment of transgenic crops. It is concluded that suspect unintended compositional effects that could be caused by genetic modification have not materialized on the basis of this substantial literature. Hence, compositional equivalence studies uniquely required for GM crops may no longer be justified on the basis of scientific uncertainty.

  5. Metabolism-based herbicide resistance and cross-resistance in crop weeds: a threat to herbicide sustainability and global crop production.

    PubMed

    Yu, Qin; Powles, Stephen

    2014-11-01

    Weedy plant species that have evolved resistance to herbicides due to enhanced metabolic capacity to detoxify herbicides (metabolic resistance) are a major issue. Metabolic herbicide resistance in weedy plant species first became evident in the 1980s in Australia (in Lolium rigidum) and the United Kingdom (in Alopecurus myosuroides) and is now increasingly recognized in several crop-weed species as a looming threat to herbicide sustainability and thus world crop production. Metabolic resistance often confers resistance to herbicides of different chemical groups and sites of action and can extend to new herbicide(s). Cytochrome P450 monooxygenase, glycosyl transferase, and glutathione S-transferase are often implicated in herbicide metabolic resistance. However, precise biochemical and molecular genetic elucidation of metabolic resistance had been stalled until recently. Complex cytochrome P450 superfamilies, high genetic diversity in metabolic resistant weedy plant species (especially cross-pollinated species), and the complexity of genetic control of metabolic resistance have all been barriers to advances in understanding metabolic herbicide resistance. However, next-generation sequencing technologies and transcriptome-wide gene expression profiling are now revealing the genes endowing metabolic herbicide resistance in plants. This Update presents an historical review to current understanding of metabolic herbicide resistance evolution in weedy plant species.

  6. Metabolism-Based Herbicide Resistance and Cross-Resistance in Crop Weeds: A Threat to Herbicide Sustainability and Global Crop Production1

    PubMed Central

    Yu, Qin; Powles, Stephen

    2014-01-01

    Weedy plant species that have evolved resistance to herbicides due to enhanced metabolic capacity to detoxify herbicides (metabolic resistance) are a major issue. Metabolic herbicide resistance in weedy plant species first became evident in the 1980s in Australia (in Lolium rigidum) and the United Kingdom (in Alopecurus myosuroides) and is now increasingly recognized in several crop-weed species as a looming threat to herbicide sustainability and thus world crop production. Metabolic resistance often confers resistance to herbicides of different chemical groups and sites of action and can extend to new herbicide(s). Cytochrome P450 monooxygenase, glycosyl transferase, and glutathione S-transferase are often implicated in herbicide metabolic resistance. However, precise biochemical and molecular genetic elucidation of metabolic resistance had been stalled until recently. Complex cytochrome P450 superfamilies, high genetic diversity in metabolic resistant weedy plant species (especially cross-pollinated species), and the complexity of genetic control of metabolic resistance have all been barriers to advances in understanding metabolic herbicide resistance. However, next-generation sequencing technologies and transcriptome-wide gene expression profiling are now revealing the genes endowing metabolic herbicide resistance in plants. This Update presents an historical review to current understanding of metabolic herbicide resistance evolution in weedy plant species. PMID:25106819

  7. Engineering pathogen resistance in crop plants: current trends and future prospects.

    PubMed

    Collinge, David B; Jørgensen, Hans J L; Lund, Ole S; Lyngkjaer, Michael F

    2010-01-01

    Transgenic crops are now grown commercially in 25 countries worldwide. Although pathogens represent major constraints for the growth of many crops, only a tiny proportion of these transgenic crops carry disease resistance traits. Nevertheless, transgenic disease-resistant plants represent approximately 10% of the total number of approved field trials in North America, a proportion that has remained constant for 15 years. In this review, we explore the socioeconomic and biological reasons for the paradox that although technically useful solutions now exist for providing transgenic disease resistance, very few new crops have been introduced to the global market. For bacteria and fungi, the majority of transgenic crops in trials express antimicrobial proteins. For viruses, three-quarters of the transgenics express coat protein (CP) genes. There is a notable trend toward more biologically sophisticated solutions involving components of signal transduction pathways regulating plant defenses. For viruses, RNA interference is increasingly being used.

  8. Plant Defense against Herbivorous Pests: Exploiting Resistance and Tolerance Traits for Sustainable Crop Protection

    PubMed Central

    Mitchell, Carolyn; Brennan, Rex M.; Graham, Julie; Karley, Alison J.

    2016-01-01

    Interactions between plants and insect herbivores are important determinants of plant productivity in managed and natural vegetation. In response to attack, plants have evolved a range of defenses to reduce the threat of injury and loss of productivity. Crop losses from damage caused by arthropod pests can exceed 15% annually. Crop domestication and selection for improved yield and quality can alter the defensive capability of the crop, increasing reliance on artificial crop protection. Sustainable agriculture, however, depends on reduced chemical inputs. There is an urgent need, therefore, to identify plant defensive traits for crop improvement. Plant defense can be divided into resistance and tolerance strategies. Plant traits that confer herbivore resistance typically prevent or reduce herbivore damage through expression of traits that deter pests from settling, attaching to surfaces, feeding and reproducing, or that reduce palatability. Plant tolerance of herbivory involves expression of traits that limit the negative impact of herbivore damage on productivity and yield. Identifying the defensive traits expressed by plants to deter herbivores or limit herbivore damage, and understanding the underlying defense mechanisms, is crucial for crop scientists to exploit plant defensive traits in crop breeding. In this review, we assess the traits and mechanisms underpinning herbivore resistance and tolerance, and conclude that physical defense traits, plant vigor and herbivore-induced plant volatiles show considerable utility in pest control, along with mixed species crops. We highlight emerging approaches for accelerating the identification of plant defensive traits and facilitating their deployment to improve the future sustainability of crop protection. PMID:27524994

  9. Crop advisor perceptions of giant ragweed distribution, herbicide-resistance, and management in the Corn Belt

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Giant ragweed has been increasing as a major weed of row crops in North America. We conducted a web-based survey of Certified Crop Advisors in the Corn Belt to determine the current distribution of giant ragweed, the distribution of herbicide resistant populations, and management and ecological fact...

  10. Glyphosate-Resistant Crops and Weeds: Now and in the Future

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glyphosate-resistant crops (GRCs) represent more than 80% of the 120 million ha of transgenic crops grown annually world-wide. This single trait has been enthusiastically adopted in soybean, maize, cotton, canola, and sugarbeet in large part because of the economic advantage of the technology, in a...

  11. Relevance of Bt toxin interaction studies for environmental risk assessment of genetically modified crops.

    PubMed

    De Schrijver, Adinda; De Clercq, Patrick; de Maagd, Ruud A; van Frankenhuyzen, Kees

    2015-12-01

    In recent years, different Bacillus thuringiensis (Bt) toxin-encoding genes have been combined or 'stacked' in genetically modified (GM) crops. Synergism between Bt proteins may occur and thereby increase the impact of the stacked GM event on nontarget invertebrates compared to plants expressing a single Bt gene. On the basis of bioassay data available for Bt toxins alone or in combination, we argue that the current knowledge of Bt protein interactions is of limited relevance in environmental risk assessment (ERA).

  12. Outcrossing potential between 11 important genetically modified crops and the Chilean vascular flora.

    PubMed

    Sánchez, Miguel A; Cid, Pablo; Navarrete, Humberto; Aguirre, Carlos; Chacón, Gustavo; Salazar, Erika; Prieto, Humberto

    2016-02-01

    The potential impact of genetically modified (GM) crops on biodiversity is one of the main concerns in an environmental risk assessment (ERA). The likelihood of outcrossing and pollen-mediated gene flow from GM crops and non-GM crops are explained by the same principles and depend primarily on the biology of the species. We conducted a national-scale study of the likelihood of outcrossing between 11 GM crops and vascular plants in Chile by use of a systematized database that included cultivated, introduced and native plant species in Chile. The database included geographical distributions and key biological and agronomical characteristics for 3505 introduced, 4993 native and 257 cultivated (of which 11 were native and 246 were introduced) plant species. Out of the considered GM crops (cotton, soya bean, maize, grape, wheat, rice, sugar beet, alfalfa, canola, tomato and potato), only potato and tomato presented native relatives (66 species total). Introduced relative species showed that three GM groups were formed having: a) up to one introduced relative (cotton and soya bean), b) up to two (rice, grape, maize and wheat) and c) from two to seven (sugar beet, alfalfa, canola, tomato and potato). In particular, GM crops presenting introduced noncultivated relative species were canola (1 relative species), alfalfa (up to 4), rice (1), tomato (up to 2) and potato (up to 2). The outcrossing potential between species [OP; scaled from 'very low' (1) to 'very high' (5)] was developed, showing medium OPs (3) for GM-native relative interactions when they occurred, low (2) for GMs and introduced noncultivated and high (4) for the grape-Vitis vinifera GM-introduced cultivated interaction. This analytical tool might be useful for future ERA for unconfined GM crop release in Chile.

  13. Notification: Evaluation of EPA's Management of Resistance Issues Related to Herbicide Tolerant Genetically Engineered Crops

    EPA Pesticide Factsheets

    Project #OPE-FY16-0023, March 25, 2016. The EPA OIG plans to begin preliminary research to assess the EPA's management and oversight of resistance issues related to herbicide tolerant genetically engineered crops.

  14. A case study for assessment of microbial community dynamics in genetically modified Bt cotton crop fields.

    PubMed

    Kapur, Manisha; Bhatia, Ranjana; Pandey, Gunjan; Pandey, Janmejay; Paul, Debarati; Jain, Rakesh K

    2010-08-01

    Bt cotton was the first genetically modified crop approved for use in India. However, only a few studies have been conducted to assess the feasibility of its commercial application. Bt cotton is genetically modified to express a proteinaceous endotoxin (Cry) encoded by cry gene of Bacillus thuringiensis that has specific insecticidal activity against bollworms. Therefore, the amount of pesticides used for growing Bt cotton is postulated to be considerably low as compared to their non-Bt counterparts. Alternatively, it is also speculated that application of a genetically modified crop may alter the bio-geochemical balance of the agriculture field(s). Microbial community composition and dynamics is an important descriptor for assessment of such alterations. In the present study, we have assessed the culturable and non-culturable microbial diversities in Bt cotton and non-Bt cotton soils to determine the ecological consequences of application of Bt cotton. The analyses of microbial community structures indicated that cropping of Bt cotton did not adversely affect the diversity of the microbial communities.

  15. A flame-resistant modified polystyrene

    NASA Technical Reports Server (NTRS)

    Karle, D. W.; Kratze, R. H.; Pacioren, K. L.

    1975-01-01

    Several modified polystyrenes have been developed that are self-extinguishing in air. Information is included in report that also describes molding and fabrication properties, toxicology, and thermal behavior of the polymers.

  16. Taxonomic and life history bias in herbicide resistant weeds: implications for deployment of resistant crops.

    PubMed

    Holt, Jodie S; Welles, Shana R; Silvera, Katia; Heap, Ian M; Heredia, Sylvia M; Martinez-Berdeja, Alejandra; Palenscar, Kai T; Sweet, Lynn C; Ellstrand, Norman C

    2013-01-01

    Evolved herbicide resistance (EHR) is an important agronomic problem and consequently a food security problem, as it jeopardizes herbicide effectiveness and increases the difficulty and cost of weed management. EHR in weeds was first reported in 1970 and the number of cases has accelerated dramatically over the last two decades. Despite 40 years of research on EHR, why some weeds evolve resistance and others do not is poorly understood. Here we ask whether weed species that have EHR are different from weeds in general. Comparing taxonomic and life history traits of weeds with EHR to a control group ("the world's worst weeds"), we found weeds with EHR significantly over-represented in certain plant families and having certain life history biases. In particular, resistance is overrepresented in Amaranthaceae, Brassicaceae and Poaceae relative to all weeds, and annuality is ca. 1.5 times as frequent in weeds with EHR as in the control group. Also, for perennial EHR weeds, vegetative reproduction is only 60% as frequent as in the control group. We found the same trends for subsets of weeds with EHR to acetolactate synthase (ALS), photosystem II (PSII), and 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase-inhibitor herbicides and with multiple resistance. As herbicide resistant crops (transgenic or not) are increasingly deployed in developing countries, the problems of EHR could increase in those countries as it has in the USA if the selecting herbicides are heavily applied and appropriate management strategies are not employed. Given our analysis, we make some predictions about additional species that might evolve resistance.

  17. METHODS FOR DETERMINING EXPOSURE TO AND POTENTIAL ECOLOGICAL EFFECTS OF GENE FLOW FROM GENETICALLY MODIFIED CROPS TO COMPATIBLE RELATIVES

    EPA Science Inventory

    SCIENCE QUESTIONS:

    -Does gene flow occur from genetically modified (GM) crop plants to compatible plants?

    -How can it be measured?

    -Are there ecological consequences of GM crop gene flow to plant communities?



    RESEARCH:

    The objectives ...

  18. The global income and production effects of genetically modified (GM) crops 1996-2011.

    PubMed

    Brookes, Graham; Barfoot, Peter

    2013-01-01

    A key part of any assessment of the global value of crop biotechnology in agriculture is an examination of its economic impact at the farm level. This paper follows earlier annual studies which examined economic impacts on yields, key costs of production, direct farm income and effects and impacts on the production base of the four main crops of soybeans, corn, cotton and canola. The commercialization of genetically modified (GM) crops has continued to occur at a rapid rate, with important changes in both the overall level of adoption and impact occurring in 2011. This annual updated analysis shows that there have been very significant net economic benefits at the farm level amounting to $19.8 billion in 2011 and $98.2 billion for the 16 year period (in nominal terms). The majority (51.2%) of these gains went to farmers in developing countries. GM technology have also made important contributions to increasing global production levels of the four main crops, having added 110 million tonnes and 195 million tonnes respectively, to the global production of soybeans and maize since the introduction of the technology in the mid-1990s.

  19. Field-evolved insect resistance to Bt crops: definition, theory, and data.

    PubMed

    Tabashnik, Bruce E; Van Rensburg, J B J; Carrière, Yves

    2009-12-01

    Transgenic crops producing Bacillus thuringiensis (Bt) toxins for insect pest control have been successful, but their efficacy is reduced when pests evolve resistance. Here we review the definition of field-evolved resistance, the relationship between resistance and field control problems, the theory underlying strategies for delaying resistance, and resistance monitoring methods. We also analyze resistance monitoring data from five continents reported in 41 studies that evaluate responses of field populations of 11 lepidopteran pests to four Bt toxins produced by Bt corn and cotton. After more than a decade since initial commercialization of Bt crops, most target pest populations remain susceptible, whereas field-evolved resistance has been documented in some populations of three noctuid moth species: Spodoptera frugiperda (J. E. Smith) to Cry1F in Bt corn in Puerto Rico, Busseola fusca (Fuller) to CrylAb in Bt corn in South Africa, and Helicoverpa zea (Boddie) to CrylAc and Cry2Ab in Bt cotton in the southeastern United States. Field outcomes are consistent with predictions from theory, suggesting that factors delaying resistance include recessive inheritance of resistance, abundant refuges of non-Bt host plants, and two-toxin Bt crops deployed separately from one-toxin Bt crops. The insights gained from systematic analyses of resistance monitoring data may help to enhance the durability of transgenic insecticidal crops. We recommend continued use of the longstanding definition of resistance cited here and encourage discussions about which regulatory actions, if any, should be triggered by specific data on the magnitude, distribution, and impact of field-evolved resistance.

  20. Efficacy of genetically modified Bt toxins alone and in combinations against pink bollworm resistant to Cry1Ac and Cry2Ab

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evolution of resistance in pests threatens the long-term success of transgenic crops that produce insecticidal proteins from Bacillus thuringiensis (Bt). Previous work showed that genetically modified Bt toxins Cry1AbMod and Cry1AcMod effectively countered resistance to native Bt toxins Cry1Ab and ...

  1. A quantitative immunopolymerase chain reaction method for detection of vegetative insecticidal protein in genetically modified crops.

    PubMed

    Kumar, Rajesh

    2011-10-12

    Vegetative insecticidal protein (Vip) is being employed for transgenic expression in selected crops such as cotton, brinjal, and corn. For regulatory compliance, there is a need for a sensitive and reliable detection method, which can distinguish between approved and nonapproved genetically modified (GM) events and quantify GM contents as well. A quantitative immunopolymerase chain reaction (IPCR) method has been developed for the detection and quantification of Vip protein in GM crops. The developed assay displayed a detection limit of 1 ng/mL (1 ppb) and linear quantification range between 10 and 1000 ng/mL of Vip-S protein. The sensitivity of the assay was found to be 10 times higher than an analogous enzyme-linked immunosorbent assay for Vip-S protein. The results suggest that IPCR has the potential to become a standard method to quantify GM proteins.

  2. Derivation and interpretation of hazard quotients to assess ecological risks from the cultivation of insect-resistant transgenic crops.

    PubMed

    Raybould, Alan; Caron-Lormier, Geoffrey; Bohan, David A

    2011-06-08

    Cost-effective and rigorous risk assessments for chemicals may be based on hazard quotients (HQs): the ratio of a measure of exposure to a substance and a measure of the effect of that substance. HQs have been used for many years in ecological risk assessments for the use of synthetic pesticides in agriculture, and methods for calculating pesticide HQs have been adapted for use with transgenic crops. This paper describes how laboratory methods for assessing the ecotoxicological effects of synthetic pesticides have been modified for the measurement of effects of insecticidal proteins, and how these effect measures are combined with exposure estimates to derive HQs for assessing the ecological risks from the cultivation of insect-resistant transgenic crops. The potential for ecological modeling to inform the design of laboratory effects tests for insecticidal proteins is also discussed.

  3. Are Herbicide Resistant Crops The Answer To Controlling Cascuta?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Herbicide tolerant crop technology could provide new management strategies for the control of parasitic plants. Three herbicide-tolerant oilseed rape genotypes were used to examine the response of attached C. campestris to glyphosate, imazamox and glufosinate. C. campestris was allowed to establi...

  4. Mini Review: Potential Applications of Non-host Resistance for Crop Improvement

    PubMed Central

    Lee, Seonghee; Whitaker, Vance M.; Hutton, Samuel F.

    2016-01-01

    Plant breeding for disease resistance is crucial to sustain global crop production. For decades, plant breeders and researchers have extensively used host plant resistance genes (R-genes) to develop disease resistant cultivars. However, the general instability of R-genes in crop cultivars when challenged with diverse pathogen populations emphasizes the need for more stable means of resistance. Alternatively, non-host resistance is recognized as the most durable, broad-spectrum form of resistance against the majority of potential pathogens in plants and has gained great attention as an alternative target for managing resistance. While transgenic approaches have been utilized to transfer non-host resistance to host species, conventional breeding applications have been more elusive. Nevertheless, avenues for discovery and deployment of genetic loci for non-host resistance via hybridization are increasingly abundant, particularly when transferring genes among closely related species. In this mini review, we discuss current and developing applications of non-host resistance for crop improvement with a focus on the overlap between host and non-host mechanisms and the potential impacts of new technology. PMID:27462329

  5. Britain's genetically modified crop controversies: the Agriculture and Environment Biotechnology Commission and the negotiation of 'uncertainty'.

    PubMed

    Grove-White, Robin

    2006-01-01

    The genetically modified crop controversies in Britain between 1997 and 2004 involved tensions surrounding the role of science in policy. The author of the paper was a member of the Agriculture and Environment Biotechnology Commission, a novel government advisory body created in 2000, which played a central role in negotiating new policy frameworks. The commission was also a key influence in the creation and execution of the three-pronged official 'GM dialogue' in 2002 and 2003. New understandings of 'uncertainty', both scientific and social, emerged as a result. The outcomes have relevance for the future political handling of other technological fields, including human genetics.

  6. Recent patents on biosafety strategies of selectable marker genes in genetically modified crops.

    PubMed

    Jiang, Yiming; Hu, Xiaoning; Huang, Haiying

    2014-01-01

    Genetically modified crops (GMCs) have been planted world wide since 1990s, but the potential insecurity of selectable marker genes raises the questions about GMC safety. Therefore, several researches have been conducted on marker gene safety issues and recently several patents have been issued on this subject. There are two main approaches to achieve this goal: seeking the biosafety selectable marker and eliminating these insecure marker genes after transformation. Results show that these two systems are quite effective. Recent patents on the two ways are discussed in this review.

  7. Resistance Management Monitoring For the US Corn Crop

    EPA Science Inventory

    Significant increases in genetically modified corn planting are expected for future planted acreages approaching 80% of total corn plantings anticipated by 2009. As demand increases, incidence of farmer non-compliance with mandated non-genetically modified refuge is likely to in...

  8. Invertebrates and vegetation of field margins adjacent to crops subject to contrasting herbicide regimes in the Farm Scale Evaluations of genetically modified herbicide-tolerant crops.

    PubMed Central

    Roy, D B; Bohan, D A; Haughton, A J; Hill, M O; Osborne, J L; Clark, S J; Perry, J N; Rothery, P; Scott, R J; Brooks, D R; Champion, G T; Hawes, C; Heard, M S; Firbank, L G

    2003-01-01

    The effects of management of genetically modified herbicide-tolerant (GMHT) crops on adjacent field margins were assessed for 59 maize, 66 beet and 67 spring oilseed rape sites. Fields were split into halves, one being sown with a GMHT crop and the other with the equivalent conventional non-GMHT crop. Margin vegetation was recorded in three components of the field margins. Most differences were in the tilled area, with fewer smaller effects mirroring them in the verge and boundary. In spring oilseed rape fields, the cover, flowering and seeding of plants were 25%, 44% and 39% lower, respectively, in the GMHT uncropped tilled margins. Similarly, for beet, flowering and seeding were 34% and 39% lower, respectively, in the GMHT margins. For maize, the effect was reversed, with plant cover and flowering 28% and 67% greater, respectively, in the GMHT half. Effects on butterflies mirrored these vegetation effects, with 24% fewer butterflies in margins of GMHT spring oilseed rape. The likely cause is the lower nectar supply in GMHT tilled margins and crop edges. Few large treatment differences were found for bees, gastropods or other invertebrates. Scorching of vegetation by herbicide-spray drift was on average 1.6% on verges beside conventional crops and 3.7% beside GMHT crops, the difference being significant for all three crops. PMID:14561320

  9. Endophytic fungi: resource for gibberellins and crop abiotic stress resistance.

    PubMed

    Khan, Abdul Latif; Hussain, Javid; Al-Harrasi, Ahmed; Al-Rawahi, Ahmed; Lee, In-Jung

    2015-03-01

    The beneficial effects of endophytes on plant growth are important for agricultural ecosystems because they reduce the need for fertilizers and decrease soil and water pollution while compensating for environmental perturbations. Endophytic fungi are a novel source of bioactive secondary metabolites; moreover, recently they have been found to produce physiologically active gibberellins as well. The symbiosis of gibberellins producing endophytic fungi with crops can be a promising strategy to overcome the adverse effects of abiotic stresses. The association of such endophytes has not only increased plant biomass but also ameliorated plant-growth during extreme environmental conditions. Endophytic fungi represent a trove of unexplored biodiversity and a frequently overlooked component of crop ecology. The present review describes the role of gibberellins producing endophytic fungi, suggests putative mechanisms involved in plant endophyte stress interactions and discusses future prospects in this field.

  10. The socioeconomics of genetically modified biofortified crops: a systematic review and meta-analysis.

    PubMed

    De Steur, Hans; Wesana, Joshua; Blancquaert, Dieter; Van Der Straeten, Dominique; Gellynck, Xavier

    2017-02-01

    Building upon the growing interest and research on genetically modified (GM) biofortification, its socioeconomic potential has been increasingly examined. We conducted two systematic reviews and meta-analyses to provide comprehensive evidence of consumers' willingness to pay (11 economic valuation studies, 64 estimates) and cost-effectiveness/benefits (five economic evaluation studies, 30 estimates). Worldwide, consumers were willing to pay 23.9% more for GM biofortified food crops. Aside from crop and design-related differences, information provision was deemed crucial. Positive information (nutrition and GM benefits) is associated with the highest consumer willingness to pay, compared with negative, objective, and conflicting GM information, especially when negative information was mentioned last. This health intervention would reduce the aggregated micronutrient deficiency burden in Asia (15.6 million disability-adjusted life years (DALYs)) by 12.5-51.4%, at a low cost of USD 7.9-27.8 per DALY in a pessimistic and optimistic scenario, respectively. Given that GM biofortified crops could tackle hidden hunger in a cost-effective and well-accepted way, its implementation is worth pursuing. A case study on folate biofortification further elaborates on the importance of socioeconomic research and the determinants of their market potential.

  11. Ecological Compatibility of GM Crops and Biological Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insect-resistant and herbicide-tolerant genetically modified (GM) crops pervade many modern cropping systems, and present challenges and opportunities for developing biologically-based pest management programs. Interactions between biological control agents (insect predators, parasitoids, and pathog...

  12. Genetic basis and detection of unintended effects in genetically modified crop plants.

    PubMed

    Ladics, Gregory S; Bartholomaeus, Andrew; Bregitzer, Phil; Doerrer, Nancy G; Gray, Alan; Holzhauser, Thomas; Jordan, Mark; Keese, Paul; Kok, Esther; Macdonald, Phil; Parrott, Wayne; Privalle, Laura; Raybould, Alan; Rhee, Seung Yon; Rice, Elena; Romeis, Jörg; Vaughn, Justin; Wal, Jean-Michel; Glenn, Kevin

    2015-08-01

    In January 2014, an international meeting sponsored by the International Life Sciences Institute/Health and Environmental Sciences Institute and the Canadian Food Inspection Agency titled "Genetic Basis of Unintended Effects in Modified Plants" was held in Ottawa, Canada, bringing together over 75 scientists from academia, government, and the agro-biotech industry. The objectives of the meeting were to explore current knowledge and identify areas requiring further study on unintended effects in plants and to discuss how this information can inform and improve genetically modified (GM) crop risk assessments. The meeting featured presentations on the molecular basis of plant genome variability in general, unintended changes at the molecular and phenotypic levels, and the development and use of hypothesis-driven evaluations of unintended effects in assessing conventional and GM crops. The development and role of emerging "omics" technologies in the assessment of unintended effects was also discussed. Several themes recurred in a number of talks; for example, a common observation was that no system for genetic modification, including conventional methods of plant breeding, is without unintended effects. Another common observation was that "unintended" does not necessarily mean "harmful". This paper summarizes key points from the information presented at the meeting to provide readers with current viewpoints on these topics.

  13. Establishment of a system based on universal multiplex-PCR for screening genetically modified crops.

    PubMed

    Lu, I-Jen; Lin, Chih-Hui; Pan, Tzu-Ming

    2010-03-01

    The rapid development of many genetically modified (GM) crops in the past two decades makes it necessary to introduce an alternative strategy for routine screening and identification. In this study, we established a universal multiplex PCR detection system which will effectively reduce the number of reactions needed for sample identification. The PCR targets of this system include the six most frequently used transgenic elements: cauliflower mosaic virus (CaMV) 35S promoter, Agrobacterium tumefaciens nopaline synthase (nos) promoter, Agrobacterium tumefaciens nopaline synthase (nos) terminator, the neomycin phosphotransferase II (nptII) gene, the 5-enolpyruvylshikimate-3-phosphate synthase (CP4 epsps) gene of Agrobacterium tumefaciens strain CP4, and the phosphinothricin N-acetyltransferase (pat) gene. According to the AGBIOS database, the coverage of this detection system is 93% of commercial GM crops. This detection system could detect all certified reference materials (CRMs) at the 1.0% level. The correct combination of all the CRM amplicon patterns proved the specificity of this multiplex PCR system. Furthermore, the amplicon patterns of this multiplex PCR detection system could be used as an index of classification which will narrow the range of possible GM products. The simulation result of this multiplex PCR detection system on all commercialized 139 GM products in the AGBIOS database showed that the maximum number of PCR reactions needed to identify an unknown sample can be reduced to 13. In this study, we established a high-throughput multiplex PCR detection system with feasible sensitivity, specificity, and cost. By incorporating this detection system, the routine GM crop-detection process will meet the challenges resulting from a rapid increase in the number of GM crops in the future.

  14. The design and implementation of insect resistance management programs for Bt crops.

    PubMed

    Head, Graham P; Greenplate, John

    2012-01-01

    Cotton and corn plants with insect resistance traits introduced through biotechnological methods and derived from the bacterium Bacillus thuringiensis (Bt) have been widely adopted since they were first introduced in 1996. Because of concerns about resistance evolving to these Bt crops, they have been released with associated IRM programs that employ multiple components and reflect the input of academic, industrial and regulatory experts. This paper summarizes the current status of Bt crop technologies in cotton and corn, the principles of IRM for Bt crops and what they mean for the design of IRM programs. It describes how these IRM programs have been implemented and some of the key factors affecting successful implementation. Finally, it suggests how they may evolve to properly steward these traits in different geographies around the world. The limited number of reported cases of resistance after more than 15 years of intensive global use of Bt crops suggest that this exercise has been broadly successful. Where resistance issues have been observed, they have been associated with first generation technologies and incomplete or compromised IRM programs (i.e., inadequate structured refuge). Next generation technologies with multiple pyramided modes of action, together with the implementation of IRM strategies that are more dependent upon manufacturing and less dependent upon grower behavior, such as seed mixes, should further enhance IRM programs for Bt crops.

  15. Crop systems and plant roots can modify the soil water holding capacity

    NASA Astrophysics Data System (ADS)

    Doussan, Claude; Cousin, Isabelle; Berard, Annette; Chabbi, Abad; Legendre, Laurent; Czarnes, Sonia; Toussaint, Bruce; Ruy, Stéphane

    2015-04-01

    At the interface between atmosphere and deep sub-soil, the root zone plays a major role in regulating the flow of water between major compartments: groundwater / surface / atmosphere (drainage, runoff, evapotranspiration). This role of soil as regulator/control of water fluxes, but also as a supporting medium to plant growth, is strongly dependent on the hydric properties of the soil. In turn, the plant roots growing in the soil can change its structure; both in the plow layer and in the deeper horizons and, therefore, could change the soil properties, particularly hydric properties. Such root-related alteration of soil properties can be linked to direct effect of roots such as soil perforation during growth, aggregation of soil particles or indirect effects such as the release of exudates by roots that could modify the properties of water or of soil particles. On an another hand, the rhizosphere, the zone around roots influenced by the activity of root and associated microorganisms, could have a high influence on hydric properties, particularly the water retention. To test if crops and plant roots rhizosphere may have a significant effect on water retention, we conducted various experiment from laboratory to field scales. In the lab, we tested different soil and species for rhizospheric effect on soil water retention. Variation in available water content (AWC) between bulk and rhizospheric soil varied from non-significant to a significant increase (to about 16% increase) depending on plant species and soil type. In the field, the alteration of water retention by root systems was tested in different pedological settings for a Maize crop inoculated or not with the bacteria Azospirillum spp., known to alter root structure, growth and morphology. Again, a range of variation in AWC was evidenced, with significant increase (~30%) in some soil types, but more linked to innoculated/non-innoculated plants rather than to a difference between rhizospheric and bulk soil

  16. Spatio-Temporal Variation in Landscape Composition May Speed Resistance Evolution of Pests to Bt Crops.

    PubMed

    Ives, Anthony R; Paull, Cate; Hulthen, Andrew; Downes, Sharon; Andow, David A; Haygood, Ralph; Zalucki, Myron P; Schellhorn, Nancy A

    2017-01-01

    Transgenic crops that express insecticide genes from Bacillus thuringiensis (Bt) are used worldwide against moth and beetle pests. Because these engineered plants can kill over 95% of susceptible larvae, they can rapidly select for resistance. Here, we use a model for a pyramid two-toxin Bt crop to explore the consequences of spatio-temporal variation in the area of Bt crop and non-Bt refuge habitat. We show that variability over time in the proportion of suitable non-Bt breeding habitat, Q, or in the total area of Bt and suitable non-Bt habitat, K, can increase the overall rate of resistance evolution by causing short-term surges of intense selection. These surges can be exacerbated when temporal variation in Q and/or K cause high larval densities in refuges that increase density-dependent mortality; this will give resistant larvae in Bt fields a relative advantage over susceptible larvae that largely depend on refuges. We address the effects of spatio-temporal variation in a management setting for two bollworm pests of cotton, Helicoverpa armigera and H. punctigera, and field data on landscape crop distributions from Australia. Even a small proportion of Bt fields available to egg-laying females when refuges are sparse may result in high exposure to Bt for just a single generation per year and cause a surge in selection. Therefore, rapid resistance evolution can occur when Bt crops are rare rather than common in the landscape. These results highlight the need to understand spatio-temporal fluctuations in the landscape composition of Bt crops and non-Bt habitats in order to design effective resistance management strategies.

  17. Spatio-Temporal Variation in Landscape Composition May Speed Resistance Evolution of Pests to Bt Crops

    PubMed Central

    Ives, Anthony R.; Paull, Cate; Hulthen, Andrew; Downes, Sharon; Andow, David A.; Haygood, Ralph; Zalucki, Myron P.; Schellhorn, Nancy A.

    2017-01-01

    Transgenic crops that express insecticide genes from Bacillus thuringiensis (Bt) are used worldwide against moth and beetle pests. Because these engineered plants can kill over 95% of susceptible larvae, they can rapidly select for resistance. Here, we use a model for a pyramid two-toxin Bt crop to explore the consequences of spatio-temporal variation in the area of Bt crop and non-Bt refuge habitat. We show that variability over time in the proportion of suitable non-Bt breeding habitat, Q, or in the total area of Bt and suitable non-Bt habitat, K, can increase the overall rate of resistance evolution by causing short-term surges of intense selection. These surges can be exacerbated when temporal variation in Q and/or K cause high larval densities in refuges that increase density-dependent mortality; this will give resistant larvae in Bt fields a relative advantage over susceptible larvae that largely depend on refuges. We address the effects of spatio-temporal variation in a management setting for two bollworm pests of cotton, Helicoverpa armigera and H. punctigera, and field data on landscape crop distributions from Australia. Even a small proportion of Bt fields available to egg-laying females when refuges are sparse may result in high exposure to Bt for just a single generation per year and cause a surge in selection. Therefore, rapid resistance evolution can occur when Bt crops are rare rather than common in the landscape. These results highlight the need to understand spatio-temporal fluctuations in the landscape composition of Bt crops and non-Bt habitats in order to design effective resistance management strategies. PMID:28046073

  18. Benchmark study on glyphosate-resistant crop systems in the United States. Part 2: Perspectives.

    PubMed

    Owen, Micheal D K; Young, Bryan G; Shaw, David R; Wilson, Robert G; Jordan, David L; Dixon, Philip M; Weller, Stephen C

    2011-07-01

    A six-state, 5 year field project was initiated in 2006 to study weed management methods that foster the sustainability of genetically engineered (GE) glyphosate-resistant (GR) crop systems. The benchmark study field-scale experiments were initiated following a survey, conducted in the winter of 2005-2006, of farmer opinions on weed management practices and their views on GR weeds and management tactics. The main survey findings supported the premise that growers were generally less aware of the significance of evolved herbicide resistance and did not have a high recognition of the strong selection pressure from herbicides on the evolution of herbicide-resistant (HR) weeds. The results of the benchmark study survey indicated that there are educational challenges to implement sustainable GR-based crop systems and helped guide the development of the field-scale benchmark study. Paramount is the need to develop consistent and clearly articulated science-based management recommendations that enable farmers to reduce the potential for HR weeds. This paper provides background perspectives about the use of GR crops, the impact of these crops and an overview of different opinions about the use of GR crops on agriculture and society, as well as defining how the benchmark study will address these issues.

  19. Assessing genetically modified crops to minimize the risk of increased food allergy: a review.

    PubMed

    Goodman, Richard E; Hefle, Susan L; Taylor, Steven L; van Ree, Ronald

    2005-06-01

    The first genetically modified (GM) crops approved for food use (tomato and soybean) were evaluated for safety by the United States Food and Drug Administration prior to commercial production. Among other factors, those products and all additional GM crops that have been grown commercially have been evaluated for potential increases in allergenic properties using methods that are consistent with the current understanding of food allergens and knowledge regarding the prediction of allergenic activity. Although there have been refinements, the key aspects of the evaluation have not changed. The allergenic properties of the gene donor and the host (recipient) organisms are considered in determining the appropriate testing strategy. The amino acid sequence of the encoded protein is compared to all known allergens to determine whether the protein is a known allergen or is sufficiently similar to any known allergen to indicate an increased probability of allergic cross-reactivity. Stability of the protein in the presence of acid with the stomach protease pepsin is tested as a risk factor for food allergenicity. In vitro or in vivo human IgE binding are tested when appropriate, if the gene donor is an allergen or the sequence of the protein is similar to an allergen. Serum donors and skin test subjects are selected based on their proven allergic responses to the gene donor or to material containing the allergen that was matched in sequence. While some scientists and regulators have suggested using animal models, performing broadly targeted serum IgE testing or extensive pre- or post-market clinical tests, current evidence does not support these tests as being predictive or practical. Based on the evidence to date, the current assessment process has worked well to prevent the unintended introduction of allergens in commercial GM crops.

  20. DNA Barcoding Simplifies Environmental Risk Assessment of Genetically Modified Crops in Biodiverse Regions

    PubMed Central

    Nzeduru, Chinyere V.; Ronca, Sandra; Wilkinson, Mike J.

    2012-01-01

    Transgenes encoding for insecticidal crystal (Cry) proteins from the soil-dwelling bacterium Bacillus Thuringiensis have been widely introduced into Genetically Modified (GM) crops to confer protection against insect pests. Concern that these transgenes may also harm beneficial or otherwise valued insects (so-called Non Target Organisms, NTOs) represents a major element of the Environmental Risk Assessments (ERAs) used by all countries prior to commercial release. Compiling a comprehensive list of potentially susceptible NTOs is therefore a necessary part of an ERA for any Cry toxin-containing GM crop. In partly-characterised and biodiverse countries, NTO identification is slowed by the need for taxonomic expertise and time to enable morphological identifications. This limitation represents a potentially serious barrier to timely adoption of GM technology in some developing countries. We consider Bt Cry1A cowpea (Vigna unguiculata) in Nigeria as an exemplar to demonstrate how COI barcoding can provide a simple and cost-effective means of addressing this problem. Over a period of eight weeks, we collected 163 insects from cowpea flowers across the agroecological and geographic range of the crop in Nigeria. These individuals included 32 Operational Taxonomic Units (OTUs) spanning four Orders and that could mostly be assigned to genus or species level. They included 12 Lepidopterans and two Coleopterans (both potentially sensitive to different groups of Cry proteins). Thus, barcode-assisted diagnoses were highly harmonised across groups (typically to genus or species level) and so were insensitive to expertise or knowledge gaps. Decisively, the entire study was completed within four months at a cost of less than 10,000 US$. The broader implications of the findings for food security and the capacity for safe adoption of GM technology are briefly explored. PMID:22567120

  1. DNA barcoding simplifies environmental risk assessment of genetically modified crops in biodiverse regions.

    PubMed

    Nzeduru, Chinyere V; Ronca, Sandra; Wilkinson, Mike J

    2012-01-01

    Transgenes encoding for insecticidal crystal (Cry) proteins from the soil-dwelling bacterium Bacillus Thuringiensis have been widely introduced into Genetically Modified (GM) crops to confer protection against insect pests. Concern that these transgenes may also harm beneficial or otherwise valued insects (so-called Non Target Organisms, NTOs) represents a major element of the Environmental Risk Assessments (ERAs) used by all countries prior to commercial release. Compiling a comprehensive list of potentially susceptible NTOs is therefore a necessary part of an ERA for any Cry toxin-containing GM crop. In partly-characterised and biodiverse countries, NTO identification is slowed by the need for taxonomic expertise and time to enable morphological identifications. This limitation represents a potentially serious barrier to timely adoption of GM technology in some developing countries. We consider Bt Cry1A cowpea (Vigna unguiculata) in Nigeria as an exemplar to demonstrate how COI barcoding can provide a simple and cost-effective means of addressing this problem. Over a period of eight weeks, we collected 163 insects from cowpea flowers across the agroecological and geographic range of the crop in Nigeria. These individuals included 32 Operational Taxonomic Units (OTUs) spanning four Orders and that could mostly be assigned to genus or species level. They included 12 Lepidopterans and two Coleopterans (both potentially sensitive to different groups of Cry proteins). Thus, barcode-assisted diagnoses were highly harmonised across groups (typically to genus or species level) and so were insensitive to expertise or knowledge gaps. Decisively, the entire study was completed within four months at a cost of less than 10,000 US$. The broader implications of the findings for food security and the capacity for safe adoption of GM technology are briefly explored.

  2. Genetic engineering for increasing fungal and bacterial disease resistance in crop plants.

    PubMed

    Wally, Owen; Punja, Zamir K

    2010-01-01

    We review the current and future potential of genetic engineering strategies used to make fungal and bacterial pathogen-resistant GM crops, illustrating different examples of the technologies and the potential benefits and short-falls of the strategies. There are well- established procedures for the production of transgenic plants with resistance towards these pathogens and considerable progress has been made using a range of new methodologies. There are no current commercially available transgenic plant species with increased resistance towards fungal and bacterial pathogens; only plants with increased resistance towards viruses are available. With an improved understanding of plant signaling pathways in response to a range of other pathogens, such as fungi, additional candidate genes for achieving resistance are being investigated. The potential for engineering plants for resistance against individual devastating diseases or for plants with resistance towards multiple pathogens is discussed in detail.

  3. Plant adaptation to acid soils: the molecular basis for crop aluminum resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aluminum (Al) toxicity on acid soils is a significant limitation to crop production worldwide, as approximately 50% of the world’s potentially arable soils are acidic. Because acid soils are such an important constraint to agriculture, understanding the mechanisms and genes conferring resistance to ...

  4. Glyphosate-resistant weeds of South American cropping systems: an overview.

    PubMed

    Vila-Aiub, Martin M; Vidal, Ribas A; Balbi, Maria C; Gundel, Pedro E; Trucco, Frederico; Ghersa, Claudio M

    2008-04-01

    Herbicide resistance is an evolutionary event resulting from intense herbicide selection over genetically diverse weed populations. In South America, orchard, cereal and legume cropping systems show a strong dependence on glyphosate to control weeds. The goal of this report is to review the current knowledge on cases of evolved glyphosate-resistant weeds in South American agriculture. The first reports of glyphosate resistance include populations of highly diverse taxa (Lolium multiflorum Lam., Conyza bonariensis L., C. canadensis L.). In all instances, resistance evolution followed intense glyphosate use in fruit fields of Chile and Brazil. In fruit orchards from Colombia, Parthenium hysterophorus L. has shown the ability to withstand high glyphosate rates. The recent appearance of glyphosate-resistant Sorghum halepense L. and Euphorbia heterophylla L. in glyphosate-resistant soybean fields of Argentina and Brazil, respectively, is of major concern. The evolution of glyphosate resistance has clearly taken place in those agroecosystems where glyphosate exerts a strong and continuous selection pressure on weeds. The massive adoption of no-till practices together with the utilization of glyphosate-resistant soybean crops are factors encouraging increase in glyphosate use. This phenomenon has been more evident in Argentina and Brazil. The exclusive reliance on glyphosate as the main tool for weed management results in agroecosystems biologically more prone to glyphosate resistance evolution.

  5. Use of Carabids for the Post-Market Environmental Monitoring of Genetically Modified Crops.

    PubMed

    Skoková Habuštová, Oxana; Svobodová, Zdeňka; Cagáň, Ľudovít; Sehnal, František

    2017-03-29

    Post-market environmental monitoring (PMEM) of genetically modified (GM) crops is required by EU legislation and has been a subject of debate for many years; however, no consensus on the methodology to be used has been reached. We explored the suitability of carabid beetles as surrogates for the detection of unintended effects of GM crops in general PMEM surveillance. Our study combines data on carabid communities from five maize field trials in Central Europe. Altogether, 86 species and 58,304 individuals were collected. Modeling based on the gradual elimination of the least abundant species, or of the fewest categories of functional traits, showed that a trait-based analysis of the most common species may be suitable for PMEM. Species represented by fewer than 230 individuals (all localities combined) should be excluded and species with an abundance higher than 600 should be preserved for statistical analyses. Sixteen species, representing 15 categories of functional traits fulfill these criteria, are typical dominant inhabitants of agroecocoenoses in Central Europe, are easy to determine, and their functional classification is well known. The effect of sampling year is negligible when at least four samples are collected during maize development beginning from 1 April. The recommended methodology fulfills PMEM requirements, including applicability to large-scale use. However, suggested thresholds of carabid comparability should be verified before definitive conclusions are drawn.

  6. Type of fitness cost influences the rate of evolution of resistance to transgenic Bt crops.

    PubMed

    Hackett, Sean C; Bonsall, Michael B

    2016-10-01

    The evolution of resistance to pesticides by insect pests is a significant challenge for sustainable agriculture. For transgenic crops expressing Bacillus thuringiensis (Bt), crystalline (Cry) toxins resistance evolution may be delayed by the high-dose/refuge strategy in which a non-toxic refuge is planted to promote the survival of susceptible insects. The high-dose/refuge strategy may interact with fitness costs associated with resistance alleles to further delay resistance. However, while a diverse range of fitness costs are reported in the field, they are typically represented as a fixed reduction in survival or viability which is insensitive to ecological conditions such as competition. Furthermore, the potential dynamic consequences of restricting susceptible insects to a refuge which represents only a fraction of the available space have rarely been considered.We present a generalized discrete time model which utilizes dynamic programming methods to derive the optimal management decisions for the control of a theoretical insect pest population exposed to Bt crops. We consider three genotypes (susceptible homozygotes, resistant homozygotes and heterozygotes) and implement fitness costs of resistance to Bt toxins as either a decrease in the relative competitive ability of resistant insects or as a penalty on fecundity. Model analysis is repeated and contrasted for two types of density dependence: uniform density dependence which operates equally across the landscape and heterogeneous density dependence where the intensity of competition scales inversely with patch size and is determined separately for the refuge and Bt crop.When the planting of Bt is decided optimally, fitness costs to fecundity allow for the planting of larger areas of Bt crops than equivalent fitness costs that reduce the competitive ability of resistant insects.Heterogeneous competition only influenced model predictions when the proportional area of Bt planted in each season was decided

  7. Dispersal of viable row-crop seeds of commercial agriculture by farmland birds: implication for genetically modified crops.

    PubMed

    Cummings, John L; Handley, Levis W; Macbryde, Bruce; Tupper, Shelagh K; Werner, Scott J; Byram, Zachary J

    2008-01-01

    To address some concerns about the expansion of genetically engineered pharmaceutical and industrial crops to outdoor plantings and potential impacts on the human food supply, we determined whether commercial agriculture seeds of maize or corn Zea mays L., barley Hordeum vulgare L., safflower Carthamus tinctorius L. and rice Oryza sativa L. are digested or pass viably through the digestive tract, or are transported externally, by captive mallard ducks Anas platyrhynchos L., ring-necked pheasants Phasianus colchicus L., red-winged blackbirds Agelaius phoeniceus (L.) and rock pigeons Columba livia Gmelin (with the exception of whole maize seeds which were too large to feed to the blackbirds). These crop seeds, whether free-fed or force-fed, did not pass through the digestive tract of these bird species. The birds nonetheless did retain viable seeds in the esophagus/crop and gizzard for several hours. For example, after foraging for 6 h, mallards had retained an average of 228 +/- 112 barley seeds and pheasants 192 +/- 78 in the esophagus/crop, and their germination rates were 93 and 50%, respectively. Birds externally transported seeds away from the feeding location, but in only four instances were seeds found attached to their muddy feet or legs and in no case to feathers. Risk of such crop seeds germinating, establishing and reproducing off site after transport by a bird (externally or internally) or movement of a carcass by a predator, will depend greatly on the crop and bird species, location, environmental conditions (including soil characteristics), timing, and seed condition.

  8. Development and Application of Loop-Mediated Isothermal Amplification Assays for Rapid Visual Detection of cry2Ab and cry3A Genes in Genetically-Modified Crops

    PubMed Central

    Li, Feiwu; Yan, Wei; Long, Likun; Qi, Xing; Li, Congcong; Zhang, Shihong

    2014-01-01

    The cry2Ab and cry3A genes are two of the most important insect-resistant exogenous genes and had been widely used in genetically-modified crops. To develop more effective alternatives for the quick identification of genetically-modified organisms (GMOs) containing these genes, a rapid and visual loop-mediated isothermal amplification (LAMP) method to detect the cry2Ab and cry3A genes is described in this study. The LAMP assay can be finished within 60 min at an isothermal condition of 63 °C. The derived LAMP products can be obtained by a real-time turbidimeter via monitoring the white turbidity or directly observed by the naked eye through adding SYBR Green I dye. The specificity of the LAMP assay was determined by analyzing thirteen insect-resistant genetically-modified (GM) crop events with different Bt genes. Furthermore, the sensitivity of the LAMP assay was evaluated by diluting the template genomic DNA. Results showed that the limit of detection of the established LAMP assays was approximately five copies of haploid genomic DNA, about five-fold greater than that of conventional PCR assays. All of the results indicated that this established rapid and visual LAMP assay was quick, accurate and cost effective, with high specificity and sensitivity. In addition, this method does not need specific expensive instruments or facilities, which can provide a simpler and quicker approach to detecting the cry2Ab and cry3A genes in GM crops, especially for on-site, large-scale test purposes in the field. PMID:25167136

  9. Development and application of loop-mediated isothermal amplification assays for rapid visual detection of cry2Ab and cry3A genes in genetically-modified crops.

    PubMed

    Li, Feiwu; Yan, Wei; Long, Likun; Qi, Xing; Li, Congcong; Zhang, Shihong

    2014-08-27

    The cry2Ab and cry3A genes are two of the most important insect-resistant exogenous genes and had been widely used in genetically-modified crops. To develop more effective alternatives for the quick identification of genetically-modified organisms (GMOs) containing these genes, a rapid and visual loop-mediated isothermal amplification (LAMP) method to detect the cry2Ab and cry3A genes is described in this study. The LAMP assay can be finished within 60 min at an isothermal condition of 63 °C. The derived LAMP products can be obtained by a real-time turbidimeter via monitoring the white turbidity or directly observed by the naked eye through adding SYBR Green I dye. The specificity of the LAMP assay was determined by analyzing thirteen insect-resistant genetically-modified (GM) crop events with different Bt genes. Furthermore, the sensitivity of the LAMP assay was evaluated by diluting the template genomic DNA. Results showed that the limit of detection of the established LAMP assays was approximately five copies of haploid genomic DNA, about five-fold greater than that of conventional PCR assays. All of the results indicated that this established rapid and visual LAMP assay was quick, accurate and cost effective, with high specificity and sensitivity. In addition, this method does not need specific expensive instruments or facilities, which can provide a simpler and quicker approach to detecting the cry2Ab and cry3A genes in GM crops, especially for on-site, large-scale test purposes in the field.

  10. ASSESSING POSSIBLE ECOLOGICAL RISKS OF GENETICALLY MODIFIED CROPS: GENE EXPRESSION ASSAYS AND GENETIC MONITORING OF NON-TARGET ORGANISMS

    EPA Science Inventory

    Widespread planting of genetically modified crops with the Bt transgene pesticide has led to concern over non-target effects of Bt compounds in agroecosystems. While some research suggests that non-target organisms exposed to Bt toxin exhibit reduced fecundity and increased morta...

  11. Resistance of cabbage (Brassica oleracea capitata group) crops to Mamestra brassicae.

    PubMed

    Cartea, M E; Francisco, M; Lema, M; Soengas, P; Velasco, P

    2010-10-01

    Twenty-one cabbage (Brassica oleracea capitata group) varieties, including 16 local varieties and five commercial hybrids, were screened for resistance to the moth Mamestra brassicae L. under natural and artificial conditions in northwestern Spain. Resistance was assessed as the proportion of damaged plants and damaged leaves, leaf feeding injury, and number of larvae present. Correlation coefficients among damage traits showed that a visual scale (general appearance rating) should be a useful indicator of resistance. Most local varieties were highly susceptible to M. brassicae, whereas the commercial hybrids tested were resistant in terms of head foliage consumption and number of larvae per plant. Performance of varieties was similar under natural and artificial infestation although some of them performed differently at each year. Three local varieties (MBG-BRS0057, MBG-BRS0074, and MBG-BRS0452) were highly susceptible at both natural and artificial infestation conditions being MBG-BRS0074 the most damaged variety. Two local varieties (MBG-BRS0402 and MBG-BRS0535) and commercial hybrids were identified as resistant or moderately resistant to M. brassicae. Among them, 'Corazón de Buey' and 'Cabeza negra' were the most resistant and produced compact heads. These varieties could be useful sources of resistance to obtain resistant varieties to M. brassicae or as donors of resistance to other Brassica crops. The possible role of leaf traits, head compactness, and leaf glucosinolate content in relation to M. brassicae resistance is discussed.

  12. Proposed definition of environmental damage illustrated by the cases of genetically modified crops and invasive species.

    PubMed

    Bartz, Robert; Heink, Ulrich; Kowarik, Ingo

    2010-06-01

    The introduction of non-native plant species and the release of genetically modified (GM) crops can induce environmental changes at gene to ecosystem levels. Regulatory frameworks such as the Convention on Biological Diversity or the EU Deliberate Release Directive aim to prevent environmental damage but do not define the term. Although ecologists and conservationists often refer to environmental effects of GM crops or invasive species as damage, most authors do not disclose their normative assumptions or explain why some environmental impacts are regarded as detrimental and others are not. Thus far, a concise definition of environmental damage is missing and is necessary for a transparent assessment of environmental effects or risks. Therefore, we suggest defining environmental damage as a significant adverse effect on a biotic or abiotic conservation resource (i.e., a biotic or abiotic natural resource that is protected by conservational or environmental legislation) that has an impact on the value of the conservation resource, the conservation resource as an ecosystem component, or the sustainable use of the conservation resource. This definition relies on three normative assumptions: only concrete effects on a conservation resource can be damages; only adverse effects that lead to a decrease in the value of the conservation resource can be damages; and only significant adverse effects constitute damage to a conservation resource. Applying this definition within the framework of environmental risk assessment requires further normative determinations, for example, selection of a threshold to distinguish between adverse and significant adverse effects and approaches for assessing the environmental value of conservation resources. Such determinations, however, are not part of the definition of environmental damage. Rather they are part of the definition's operationalization through assessment procedures, which must be grounded in a comprehensible definition of

  13. Cross-resistance to toxins used in pyramided Bt crops and resistance to Bt sprays in Helicoverpa zea.

    PubMed

    Welch, Kara L; Unnithan, Gopalan C; Degain, Ben A; Wei, Jizhen; Zhang, Jie; Li, Xianchun; Tabashnik, Bruce E; Carrière, Yves

    2015-11-01

    To delay evolution of resistance by insect pests, farmers are rapidly increasing their use of transgenic crops producing two or more Bacillus thuringiensis (Bt) toxins that kill the same pest. A key condition favoring durability of these "pyramided" crops is the absence of cross-resistance between toxins. Here we evaluated cross-resistance in the major lepidopteran pest Helicoverpa zea (Boddie) to Bt toxins used in pyramids. In the laboratory, we selected a strain of this pest with Bt toxin Cry1Ac followed by selection with MVP II, a formulation containing a hybrid protoxin that is identical to Cry1Ac in the active portion of the toxin and 98.5% identical overall. We calculated the resistance ratio as the EC50 (concentration causing mortality or failure to develop beyond the first instar of 50% of larvae) for the laboratory-selected strain divided by the EC50 for its field-derived parent strain that was not selected in the laboratory. The resistance ratio was 20.0-33.9 (mean=27.0) for MVP II, 57.0 for Cry1Ac, 51.3 for Cry1A.105, 22.4 for Cry1Ab, 3.3 for Cry2Ab, 1.8 for Cry1Fa, and 1.6 for Vip3Aa. Resistance ratios were 2.9 for DiPel ES and 2.0 for Agree VG, which are commercial Bt spray formulations containing Cry1Ac, other Bt toxins, and Bt spores. By the conservative criterion of non-overlap of 95% fiducial limits, the EC50 was significantly higher for the selected strain than its parent strain for MVP II, Cry1Ac, Cry1A.105, Cry1Ab, Cry2Ab and DiPel ES. For Cry1Fa, Vip3Aa, and Agree VG, significantly lower susceptibility to a high concentration indicated low cross-resistance. The resistance ratio for toxins other than Cry1Ac was associated with their amino acid sequence similarity to Cry1Ac in domain II. Resistance to Cry1Ac and the observed cross-resistance to other Bt toxins could accelerate evolution of H. zea resistance to currently registered Bt sprays and pyramided Bt crops.

  14. Environmental impacts of genetically modified (GM) crop use 1996-2014: Impacts on pesticide use and carbon emissions.

    PubMed

    Brookes, Graham; Barfoot, Peter

    2016-04-02

    This paper updates previous assessments of important environmental impacts associated with using crop biotechnology in global agriculture. It focuses on the environmental impacts associated with changes in pesticide use and greenhouse gas emissions arising from the use of GM crops since their first widespread commercial use in the mid 1990s. The adoption of GM insect resistant and herbicide tolerant technology has reduced pesticide spraying by 581.4 million kg (-8.2%) and, as a result, decreased the environmental impact associated with herbicide and insecticide use on these crops (as measured by the indicator, the Environmental Impact Quotient [EIQ]) by18.5%. The technology has also facilitated important cuts in fuel use and tillage changes, resulting in a significant reduction in the release of greenhouse gas emissions from the GM cropping area. In 2014, this was equivalent to removing nearly 10 million cars from the roads.

  15. Environmental impacts of genetically modified (GM) crop use 1996-2013: Impacts on pesticide use and carbon emissions.

    PubMed

    Brookes, Graham; Barfoot, Peter

    2015-01-01

    This paper updates previous assessments of how crop biotechnology has changed the environmental impact of global agriculture. It focuses on the environmental impacts associated with changes in pesticide use and greenhouse gas emissions arising from the use of GM crops since their first widespread commercial use in the mid 1990s. The adoption of GM insect resistant and herbicide tolerant technology has reduced pesticide spraying by 553 million kg (-8.6%) and, as a result, decreased the environmental impact associated with herbicide and insecticide use on these crops (as measured by the indicator the Environmental Impact Quotient (EIQ)) by 19.1%. The technology has also facilitated important cuts in fuel use and tillage changes, resulting in a significant reduction in the release of greenhouse gas emissions from the GM cropping area. In 2013, this was equivalent to removing 12.4 million cars from the roads.

  16. Environmental impacts of genetically modified (GM) crop use 1996–2013: Impacts on pesticide use and carbon emissions

    PubMed Central

    Brookes, Graham; Barfoot, Peter

    2015-01-01

    ABSTRACT This paper updates previous assessments of how crop biotechnology has changed the environmental impact of global agriculture. It focuses on the environmental impacts associated with changes in pesticide use and greenhouse gas emissions arising from the use of GM crops since their first widespread commercial use in the mid 1990s. The adoption of GM insect resistant and herbicide tolerant technology has reduced pesticide spraying by 553 million kg (−8.6%) and, as a result, decreased the environmental impact associated with herbicide and insecticide use on these crops (as measured by the indicator the Environmental Impact Quotient (EIQ)) by19.1%. The technology has also facilitated important cuts in fuel use and tillage changes, resulting in a significant reduction in the release of greenhouse gas emissions from the GM cropping area. In 2013, this was equivalent to removing 12.4 million cars from the roads. PMID:25760405

  17. IMI resistance associated to crop-weed hybridization in a natural Brassica rapa population: characterization and fate.

    PubMed

    Ureta, M S; Torres Carbonell, F; Pandolfo, C; Presotto, A D; Cantamutto, M A; Poverene, M

    2017-03-01

    Wild turnip (Brassica rapa) is a common weed and a close relative to oilseed rape (Brassica napus). The Clearfield® production system is a highly adopted tool which provides an alternative solution for weed management, but its efficiency is threatened by gene transfer from crop to weed relatives. Crop-weed hybrids with herbicide resistance were found in the progeny of a B. rapa population gathered from a weedy stand on the borders of an oilseed rape (B. napus) imidazolinone (IMI)-resistant crop. Interspecific hybrids were confirmed by morphological traits in the greenhouse and experimental field, survival after imazethapyr applications, DNA content through flow cytometry, and pollen viability. The transference of herbicide resistance was demonstrated even in a particular situation of pollen competition between both an herbicide-resistant crop and a non-resistant crop. However, IMI resistance was not found in further generations collected at the same location. These results verify gene transmission from oilseed rape to B. rapa in the main crop area in Argentina where resistant and susceptible varieties are found and seed loss and crop volunteers are common. Hybridization, introgression, and herbicide selection would be associated with the loss of effectiveness of IMI technology.

  18. The evolution of resistance to two-toxin pyramid transgenic crops.

    PubMed

    Ives, Anthony R; Glaum, Paul R; Ziebarth, Nicolas L; Andow, David A

    2011-03-01

    Pyramid transgenic crops that express two Bacillus thuringiensis (Bt) toxins hold great potential for reducing insect damage and slowing the evolution of resistance to the toxins. Here, we analyzed a suite of models for pyramid Bt crops to illustrate factors that should be considered when implementing the high dose-refuge strategy for resistance management; this strategy involves the high expression of toxins in Bt plants and use of non-Bt plants as refuges. Although resistance evolution to pyramid Bt varieties should in general be slower, resistance to pyramid Bt varieties is nonetheless driven by the same evolutionary processes as single Bt-toxin varieties. The main advantage of pyramid varieties is the low survival of insects heterozygous for resistance alleles. We show that there are two modes of resistance evolution. When populations of purely susceptible insects persist, leading to density dependence, the speed of resistance evolution changes slowly with the proportion of refuges. However, once the proportion of non-Bt plants crosses the threshold below which a susceptible population cannot persist, the speed of resistance evolution increases rapidly. This suggests that adaptive management be used to guarantee persistence of susceptible populations. We compared the use of seed mixtures in which Bt and non-Bt plants are sown in the same fields to the use of spatial refuges. As found for single Bt varieties, seed mixtures can speed resistance evolution if larvae move among plants. Devising optimal management plans for deploying spatial refuges is difficult because they depend on crop rotation patterns, whether males or females have limited dispersal, and other characteristics. Nonetheless, the effects of spatial refuges on resistance evolution can be understood by considering the three mechanisms determining the rate of resistance evolution: the force of selection (the proportion of insects killed by Bt), assortative mating (deviations of the proportion of

  19. [Bt transgenic crops for insect-resistance and modification of Bt protein and utilization of stacking strategy].

    PubMed

    Li, Chen; Liu, Bolin

    2015-01-01

    Insecticidal protein genes from Bacillus thuringiensis are currently the most widely used insect-resistant genes. They have been transferred to many crops for breeding and production. Among them, cotton, maize, potato and other insect-resistant crops are commercialized, creating considerable economic benefit. In this review, we summarized advances in identifying functional genes and transgenic crops for insect resistance, compared different strategies for enhancing vigor of insecticidal protein and utilizing gene stacking as well as listing valuable groups of stacked genes. In addition, the methods for multiple gene transformation was discussed.

  20. Assessment of the nutritional values of genetically modified wheat, corn, and tomato crops.

    PubMed

    Venneria, Eugenia; Fanasca, Simone; Monastra, Giovanni; Finotti, Enrico; Ambra, Roberto; Azzini, Elena; Durazzo, Alessandra; Foddai, Maria Stella; Maiani, Giuseppe

    2008-10-08

    The genetic modification in fruit and vegetables could lead to changes in metabolic pathways and, therefore, to the variation of the molecular pattern, with particular attention to antioxidant compounds not well-described in the literature. The aim of the present study was to compare the quality composition of transgenic wheat ( Triticum durum L.), corn ( Zea mays L.), and tomato ( Lycopersicum esculentum Mill.) to the nontransgenic control with a similar genetic background. In the first experiment, Ofanto wheat cultivar containing the tobacco rab1 gene and nontransgenic Ofanto were used. The second experiment compared two transgenic lines of corn containing Bacillus thuringiensis "Cry toxin" gene (PR33P67 and Pegaso Bt) to their nontransgenic forms. The third experiment was conducted on transgenic tomato ( Lycopersicum esculentum Mill.) containing the Agrobacterium rhizogenes rolD gene and its nontransgenic control (cv. Tondino). Conventional and genetically modified crops were compared in terms of fatty acids content, unsaponifiable fraction of antioxidants, total phenols, polyphenols, carotenoids, vitamin C, total antioxidant activity, and mineral composition. No significant differences were observed for qualitative traits analyzed in wheat and corn samples. In tomato samples, the total antioxidant activity (TAA), measured by FRAP assay, and the naringenin content showed a lower value in genetically modified organism (GMO) samples (0.35 mmol of Fe (2+) 100 g (-1) and 2.82 mg 100 g (-1), respectively), in comparison to its nontransgenic control (0.41 mmol of Fe (2+) 100 g (-1) and 4.17 mg 100 g (-1), respectively). On the basis of the principle of substantial equivalence, as articulated by the World Health Organization, the Organization for Economic Cooperation and Development, and the United Nations Food and Agriculture Organization, these data support the conclusion that GM events are nutritionally similar to conventional varieties of wheat, corn, and tomato on

  1. Molecular Breeding Strategy and Challenges Towards Improvement of Blast Disease Resistance in Rice Crop

    PubMed Central

    Ashkani, Sadegh; Rafii, Mohd Y.; Shabanimofrad, Mahmoodreza; Miah, Gous; Sahebi, Mahbod; Azizi, Parisa; Tanweer, Fatah A.; Akhtar, Mohd Sayeed; Nasehi, Abbas

    2015-01-01

    Rice is a staple and most important security food crop consumed by almost half of the world’s population. More rice production is needed due to the rapid population growth in the world. Rice blast caused by the fungus, Magnaporthe oryzae is one of the most destructive diseases of this crop in different part of the world. Breakdown of blast resistance is the major cause of yield instability in several rice growing areas. There is a need to develop strategies providing long-lasting disease resistance against a broad spectrum of pathogens, giving protection for a long time over a broad geographic area, promising for sustainable rice production in the future. So far, molecular breeding approaches involving DNA markers, such as QTL mapping, marker-aided selection, gene pyramiding, allele mining and genetic transformation have been used to develop new resistant rice cultivars. Such techniques now are used as a low-cost, high-throughput alternative to conventional methods allowing rapid introgression of disease resistance genes into susceptible varieties as well as the incorporation of multiple genes into individual lines for more durable blast resistance. The paper briefly reviewed the progress of studies on this aspect to provide the interest information for rice disease resistance breeding. This review includes examples of how advanced molecular method have been used in breeding programs for improving blast resistance. New information and knowledge gained from previous research on the recent strategy and challenges towards improvement of blast disease such as pyramiding disease resistance gene for creating new rice varieties with high resistance against multiple diseases will undoubtedly provide new insights into the rice disease control. PMID:26635817

  2. Molecular Breeding Strategy and Challenges Towards Improvement of Blast Disease Resistance in Rice Crop.

    PubMed

    Ashkani, Sadegh; Rafii, Mohd Y; Shabanimofrad, Mahmoodreza; Miah, Gous; Sahebi, Mahbod; Azizi, Parisa; Tanweer, Fatah A; Akhtar, Mohd Sayeed; Nasehi, Abbas

    2015-01-01

    Rice is a staple and most important security food crop consumed by almost half of the world's population. More rice production is needed due to the rapid population growth in the world. Rice blast caused by the fungus, Magnaporthe oryzae is one of the most destructive diseases of this crop in different part of the world. Breakdown of blast resistance is the major cause of yield instability in several rice growing areas. There is a need to develop strategies providing long-lasting disease resistance against a broad spectrum of pathogens, giving protection for a long time over a broad geographic area, promising for sustainable rice production in the future. So far, molecular breeding approaches involving DNA markers, such as QTL mapping, marker-aided selection, gene pyramiding, allele mining and genetic transformation have been used to develop new resistant rice cultivars. Such techniques now are used as a low-cost, high-throughput alternative to conventional methods allowing rapid introgression of disease resistance genes into susceptible varieties as well as the incorporation of multiple genes into individual lines for more durable blast resistance. The paper briefly reviewed the progress of studies on this aspect to provide the interest information for rice disease resistance breeding. This review includes examples of how advanced molecular method have been used in breeding programs for improving blast resistance. New information and knowledge gained from previous research on the recent strategy and challenges towards improvement of blast disease such as pyramiding disease resistance gene for creating new rice varieties with high resistance against multiple diseases will undoubtedly provide new insights into the rice disease control.

  3. Altering Conidial Dispersal of Alternaria solani by Modifying Microclimate in Tomato Crop Canopy

    PubMed Central

    Jambhulkar, Prashant Prakash; Jambhulkar, Nitiprasad; Meghwal, Madanlal; Ameta, Gauri Shankar

    2016-01-01

    Early blight of tomato caused by Alternaria solani, is responsible for severe yield losses in tomato. The conidia survive on soil surface and old dry lower leaves of the plant and spread when suitable climatic conditions are available. Macroclimatic study reveals that highest inoculum concentration of Alternaria spores appeared in May 2012 to 2013 and lowest concentration during January 2012 to 2013. High night temperature positively correlated and significantly (P < 0.01) involved in conidial spore dispersal and low relative humidity (RH) displayed significant (P < 0.05) but negative correlation with conidial dispersal. The objective of the study was to modify microclimatic conditions of tomato crop canopy which may hamper conidial dispersal and reduce disease severity. We evaluated effect of marigold intercropping and plastic mulching singly and in consortia on A. solani conidial density, tomato leaf damage and microclimatic parameters as compar to tomato alone (T). Tomato-marigold intercropping–plastic mulching treatment (T + M + P) showed 35–39% reduction in disease intensity as compared to tomato alone. When intercropped with tomato, marigold served as barrier to conidial movement and plastic mulching prevented evapotranspiration and reduced the canopy RH that resulted in less germination of A. solani spores. Marigold intercropping and plastic mulching served successfully as physical barrier against conidial dissemination to diminish significantly the tomato foliar damage produced by A. solani. PMID:27904457

  4. Altering Conidial Dispersal of Alternaria solani by Modifying Microclimate in Tomato Crop Canopy.

    PubMed

    Jambhulkar, Prashant Prakash; Jambhulkar, Nitiprasad; Meghwal, Madanlal; Ameta, Gauri Shankar

    2016-12-01

    Early blight of tomato caused by Alternaria solani, is responsible for severe yield losses in tomato. The conidia survive on soil surface and old dry lower leaves of the plant and spread when suitable climatic conditions are available. Macroclimatic study reveals that highest inoculum concentration of Alternaria spores appeared in May 2012 to 2013 and lowest concentration during January 2012 to 2013. High night temperature positively correlated and significantly (P < 0.01) involved in conidial spore dispersal and low relative humidity (RH) displayed significant (P < 0.05) but negative correlation with conidial dispersal. The objective of the study was to modify microclimatic conditions of tomato crop canopy which may hamper conidial dispersal and reduce disease severity. We evaluated effect of marigold intercropping and plastic mulching singly and in consortia on A. solani conidial density, tomato leaf damage and microclimatic parameters as compar to tomato alone (T). Tomato-marigold intercropping-plastic mulching treatment (T + M + P) showed 35-39% reduction in disease intensity as compared to tomato alone. When intercropped with tomato, marigold served as barrier to conidial movement and plastic mulching prevented evapotranspiration and reduced the canopy RH that resulted in less germination of A. solani spores. Marigold intercropping and plastic mulching served successfully as physical barrier against conidial dissemination to diminish significantly the tomato foliar damage produced by A. solani.

  5. Computational allergenicity prediction of transgenic proteins expressed in genetically modified crops.

    PubMed

    Verma, Alok Kumar; Misra, Amita; Subash, Swarna; Das, Mukul; Dwivedi, Premendra D

    2011-09-01

    Development of genetically modified (GM) crops is on increase to improve food quality, increase harvest yields, and reduce the dependency on chemical pesticides. Before their release in marketplace, they should be scrutinized for their safety. Several guidelines of different regulatory agencies like ILSI, WHO Codex, OECD, and so on for allergenicity evaluation of transgenics are available and sequence homology analysis is the first test to determine the allergenic potential of inserted proteins. Therefore, to test and validate, 312 allergenic, 100 non-allergenic, and 48 inserted proteins were assessed for sequence similarity using 8-mer, 80-mer, and full FASTA search. On performing sequence homology studies, ~94% the allergenic proteins gave exact matches for 8-mer and 80-mer homology. However, 20 allergenic proteins showed non-allergenic behavior. Out of 100 non-allergenic proteins, seven qualified as allergens. None of the inserted proteins demonstrated allergenic behavior. In order to improve the predictability, proteins showing anomalous behavior were tested by Algpred and ADFS separately. Use of Algpred and ADFS softwares reduced the tendency of false prediction to a great extent (74-78%). In conclusion, routine sequence homology needs to be coupled with some other bioinformatic method like ADFS/Algpred to reduce false allergenicity prediction of novel proteins.

  6. A look at product development with genetically modified crops: examples from maize.

    PubMed

    Mumm, Rita H

    2013-09-04

    Plant breeding for crop genetic improvement involves the cycle of creating genetic diversity and exploiting that diversity to derive an improved cultivar with outstanding performance for specific traits of interest. Genetic modification through transformation essentially expands the genepool to facilitate access to genes otherwise not available through crossing. Transgenic events are defined by the DNA sequence that has been incorporated into the target genome and the specific point(s) of insertion. In the development of a new transgenic trait, typically many events are generated and evaluated with the aim of identifying one exhibiting consistent trait expression at or above specified thresholds, stable inheritance, and the absence of any negative effects. With transgenic traits for maize, once commercial candidates have been identified, these events are introgressed into elite lines, often through the use of molecular markers that can accelerate the breeding process and aid in producing a quality conversion. Converted elite lines are yield-tested to ensure performance equivalency with their unconverted counterparts. Finally, before commercial sale of seed, quality control monitoring is conducted to ensure event identity and purity and the absence of any unintended events. This monitoring complements other quality control measures to confirm seed viability and line/hybrid purity and uniformity in seed treatments, all in an effort to ensure customer satisfaction and to comply with governmental regulations. Thus, genetically modified (GM) cultivars are subject to significant testing and auditing prior to seed sale and distribution to farmers, more testing and auditing than with non-GM cultivars.

  7. Detection of genetically modified crops and their derivatives: critical steps in sample preparation and extraction.

    PubMed

    Terry, Catherine F; Harris, Neil; Parkes, Helen C

    2002-01-01

    The detection of genetically modified crops in foodstuff relies on detection of transgenic DNA or protein material in the sample matrix. Purified DNA or proteins are used as analytical material for polymerase chain reaction technologies and immunodiagnostics. Successful sample preparation is critical to the validity of subsequent analysis. For routine analysis, a good sample preparation technique should be simple, safe, and inexpensive while reproducibly generating DNA/protein of sufficient quality and yield. The suitability of isolated DNA or protein as an analyte for a detection or characterization technique depends on amount or concentration, purity, and integrity, each of which may be influenced by sample matrix and the extraction technique, and, in turn, may impact the validity of analytical techniques. The key sample preparation steps of homogenization, pretreatment, extraction, and purification are discussed as well as typical analytical methods. Consideration is given to application of these steps for particular sample matrixes to maximize yield, reduce inhibition effects, and minimize contamination. The choice of the most appropriate and valid methods for sample preparation from particular foods is discussed with respect to DNA analysis. Attention is also given to ease of use, cost, and generic applicability of the procedures.

  8. [The public perception of information about the potential risks of genetically modified crops in the food chain].

    PubMed

    Furnival, Ariadne Chloë; Pinheiro, Sônia Maria

    2008-01-01

    At a time when genetically modified (GM) crops are entering the Brazilian food chain, we present the findings of a study that makes use of a qualitative technique involving focal groups to look into the public's interpretation of the information available about this biotechnological innovation. This methodology produced results that revealed the interconnections drawn by the research subjects between this form of biotechnology, changes to the environment, and food production in general. The mistrust expressed about GM crops was particularly attributed by the participants to the non-availability of comprehensible information in the mass media or on product labels.

  9. Evaluation of the Doraiswamy-Thompson winter wheat crop calendar model incorporating a modified spring restart sequence

    NASA Technical Reports Server (NTRS)

    Taylor, T. W.; Ravet, F. W.; Smika, D. (Principal Investigator)

    1981-01-01

    The Robertson phenology was used to provide growth stage information to a wheat stress indicator mode. A stress indicator model demands two acurate predictions from a crop calendar: date of spring growth initiation; and crop calendar stage at growth initiation. Several approaches for restarting the Robertson phenology model at spring growth initiation were studied. Although best results were obtained with a solar thermal unit method, an alternate approach which indicates soil temperature as the controlling parameter for spring growth initiation was selected and tested. The modified model (Doraiswamy-Thompson) is compared to LACIE-Robertson model predictions.

  10. Simulating changes in cropping practices in conventional and glyphosate-resistant maize. II. Weed impacts on crop production and biodiversity.

    PubMed

    Colbach, Nathalie; Darmency, Henri; Fernier, Alice; Granger, Sylvie; Le Corre, Valérie; Messéan, Antoine

    2017-04-06

    Overreliance on the same herbicide mode of action leads to the spread of resistant weeds, which cancels the advantages of herbicide-tolerant (HT) crops. Here, the objective was to quantify, with simulations, the impact of glyphosate-resistant (GR) weeds on crop production and weed-related wild biodiversity in HT maize-based cropping systems differing in terms of management practices. We (1) simulated current conventional and probable HT cropping systems in two European regions, Aquitaine and Catalonia, with the weed dynamics model FLORSYS; (2) quantified how much the presence of GR weeds contributed to weed impacts on crop production and biodiversity; (3) determined the effect of cultural practices on the impact of GR weeds and (4) identified which species traits most influence weed-impact indicators. The simulation study showed that during the analysed 28 years, the advent of glyphosate resistance had little effect on plant biodiversity. Glyphosate-susceptible populations and species were replaced by GR ones. Including GR weeds only affected functional biodiversity (food offer for birds, bees and carabids) and weed harmfulness when weed effect was initially low; when weed effect was initially high, including GR weeds had little effect. The GR effect also depended on cultural practices, e.g. GR weeds were most detrimental for species equitability when maize was sown late. Species traits most harmful for crop production and most beneficial for biodiversity were identified, using RLQ analyses. None of the species presenting these traits belonged to a family for which glyphosate resistance was reported. An advice table was built; the effects of cultural practices on crop production and biodiversity were synthesized, explained, quantified and ranked, and the optimal choices for each management technique were identified.

  11. Low Temperature and Modified Atmosphere: Hurdles for Antibiotic Resistance Transfer?

    PubMed

    Van Meervenne, Eva; Van Coillie, Els; Van Weyenberg, Stephanie; Boon, Nico; Herman, Lieve; Devlieghere, Frank

    2015-12-01

    Food is an important dissemination route for antibiotic-resistant bacteria. Factors used during food production and preservation may contribute to the transfer of antibiotic resistance genes, but research on this subject is scarce. In this study, the effect of temperature (7 to 37°C) and modified atmosphere packaging (air, 50% CO2-50% N2, and 100% N2) on antibiotic resistance transfer from Lactobacillus sakei subsp. sakei to Listeria monocytogenes was evaluated. Filter mating was performed on nonselective agar plates with high-density inocula. A more realistic setup was created by performing modified atmosphere experiments on cooked ham using high-density and low-density inocula. Plasmid transfer was observed between 10 and 37°C, with plasmid transfer also observed at 7°C during a prolonged incubation period. When high-density inocula were used, transconjugants were detected, both on agar plates and cooked ham, under the three atmospheres (air, 50% CO2-50% N2, and 100% N2) at 7°C. This yielded a median transfer ratio (number of transconjugants/number of recipients) with an order of magnitude of 10(-4) to 10(-6). With low-density inocula, transfer was only detected under the 100% N2 atmosphere after 10-day incubation at 7°C, yielding a transfer ratio of 10(-5). Under this condition, the highest bacterial density was obtained. The results indicate that low temperature and modified atmosphere packaging, two important hurdles in the food industry, do not necessarily prevent plasmid transfer from Lactobacillus sakei subsp. sakei to Listeria monocytogenes.

  12. Safety assessment, detection and traceability, and societal aspects of genetically modified foods. European Network on Safety Assessment of Genetically Modified Food Crops (ENTRANSFOOD). Concluding remarks.

    PubMed

    Kuiper, H A; König, A; Kleter, G A; Hammes, W P; Knudsen, I

    2004-07-01

    The most important results from the EU-sponsored ENTRANSFOOD Thematic Network project are reviewed, including the design of a detailed step-wise procedure for the risk assessment of foods derived from genetically modified crops based on the latest scientific developments, evaluation of topical risk assessment issues, and the formulation of proposals for improved risk management and public involvement in the risk analysis process.

  13. Companion cropping with potato onion enhances the disease resistance of tomato against Verticillium dahliae

    PubMed Central

    Fu, Xuepeng; Wu, Xia; Zhou, Xingang; Liu, Shouwei; Shen, Yanhui; Wu, Fengzhi

    2015-01-01

    Intercropping could alleviate soil-borne diseases, however, few studies focused on the immunity of the host plant induced by the interspecific interactions. To test whether or not intercropping could enhance the disease resistance of host plant, we investigated the effect of companion cropping with potato onion on tomato Verticillium wilt caused by Verticillium dahliae (V. dahliae). To investigate the mechanisms, the root exudates were collected from tomato and potato onion which were grown together or separately, and were used to examine the antifungal activities against V. dahliae in vitro, respectively. Furthermore, RNA-seq was used to examine the expression pattern of genes related to disease resistance in tomato companied with potato onion compared to that in tomato grown alone, under the condition of infection with V. dahliae. The results showed that companion cropping with potato onion could alleviate the incidence and severity of tomato Verticillium wilt. The further studies revealed that the root exudates from tomato companied with potato onion significantly inhibited the mycelia growth and spore germination of V. dahliae. However, there were no significant effects on these two measurements for the root exudates from potato onion grown alone or from potato onion grown with tomato. RNA-seq data analysis showed the disease defense genes associated with pathogenesis-related proteins, biosynthesis of lignin, hormone metabolism and signal transduction were expressed much higher in the tomato companied with potato onion than those in the tomato grown alone, which indicated that these defense genes play important roles in tomato against V. dahliae infection, and meant that the disease resistance of tomato against V. dahliae was enhanced in the companion copping with potato onion. We proposed that companion cropping with potato onion could enhance the disease resistance of tomato against V. dahliae by regulating the expression of genes related to disease

  14. A new method for evaluating flowering synchrony to support the temporal isolation of genetically modified crops from their wild relatives.

    PubMed

    Ohigashi, Kentaro; Mizuguti, Aki; Yoshimura, Yasuyuki; Matsuo, Kazuhito; Miwa, Tetsuhisa

    2014-01-01

    Hybridization between crops and their wild relatives potentially threatens the genetic identity of the wild plants, particularly in the case of genetically modified crops. Only a few studies have examined the use of temporal isolation to prevent hybridization, and the indices used in those studies, (e.g., the days of flowering overlap), are not precise to evaluate the degree of synchrony in flowering. Here we propose a flowering similarity index that can compare the degree of flowering synchrony between two relevant species and measure the efficiency of temporal isolation. The results showed that the flowering similarity index predicts the likelihood of hybridization much better than the number of flowering-overlap days, regardless of different flowering patterns among cultivars. Thus, temporal isolation of flowering or flowering asynchrony is the most effective means in preventing hybridization between crops and their wild relatives.

  15. Combining pest control and resistance management: synergy of engineered insects with Bt crops.

    PubMed

    Alphey, Nina; Bonsall, Michael B; Alphey, Luke

    2009-04-01

    Transgenic crops producing insecticidal toxins are widely used to control insect pests. Their benefits would be lost if resistance to the toxins became widespread in pest populations. The most widely used resistance management method is the high-dose/refuge strategy. This requires toxin-free host plants as refuges near insecticidal crops, and toxin doses intended to be sufficiently high to kill insects heterozygous for a resistant allele, thereby rendering resistance functionally recessive. We have previously shown by mathematical modeling that mass-release of harmless susceptible (toxin-sensitive) insects engineered with repressible female-specific lethality using release of insects carrying a dominant lethal ([RIDL] Oxitec Limited, United Kingdom) technology could substantially delay or reverse the spread of resistance and reduce refuge sizes. Here, we explore this proposal in depth, studying a wide range of scenarios, considering impacts on population dynamics as well as evolution of allele frequencies, comparing with releases of natural fertile susceptible insects, and examining the effect of seasonality. We investigate the outcome for pest control for which the plant-incorporated toxins are not necessarily at a high dose (i.e., they might not kill all homozygous susceptible and all heterozygous insects). We demonstrate that a RIDL-based approach could form an effective component of a resistance management strategy in a wide range of genetic and ecological circumstances. Because there are significant threshold effects for several variables, we expect that a margin of error would be advisable in setting release ratios and refuge sizes, especially as the frequency and properties of resistant alleles may be difficult to measure accurately in the field.

  16. Improving crop disease resistance: lessons from research on Arabidopsis and tomato

    PubMed Central

    Piquerez, Sophie J. M.; Harvey, Sarah E.; Beynon, Jim L.; Ntoukakis, Vardis

    2014-01-01

    One of the great challenges for food security in the 21st century is to improve yield stability through the development of disease-resistant crops. Crop research is often hindered by the lack of molecular tools, growth logistics, generation time and detailed genetic annotations, hence the power of model plant species. Our knowledge of plant immunity today has been largely shaped by the use of models, specifically through the use of mutants. We examine the importance of Arabidopsis and tomato as models in the study of plant immunity and how they help us in revealing a detailed and deep understanding of the various layers contributing to the immune system. Here we describe examples of how knowledge from models can be transferred to economically important crops resulting in new tools to enable and accelerate classical plant breeding. We will also discuss how models, and specifically transcriptomics and effectoromics approaches, have contributed to the identification of core components of the defense response which will be key to future engineering of durable and sustainable disease resistance in plants. PMID:25520730

  17. [Relationship of genetically modified crops with the environment and health of the Costa Rican human population].

    PubMed

    Espinoza, Ana M; Arrieta-Espinoza, Griselda; Sittenfeld, Ana

    2004-09-01

    Genetic engineering and the food derived from genetically modified crops (GMCs) have been the center of debate worldwide, as has occurred historically with the advent of new technologies. Questions are derived from the potential impact of GMCs to the environment and the safety of the products to the consumers. In relation to the first inquiry, practice has been oriented to a case-by-case-study, according to the own characteristics of the GMC, in order to minimize its impact in the environment. Scientific studies in diverse latitudes of the world have demonstrated that GMCs in the market showed no adverse effects related to this issue. In relation to food derived from the GMCs, rigorous evaluation protocols have been developed and approved by FAO and WHO to guarantee the innocuousness of these products. Up to the moment, no contraindications for human health have been pointed out for the products that are available today in the market. In the particular case of Costa Rica, the country has established since the 90s a regulatory biosafety framework for the management of the GMCs, safeguarding the biodiversity of the country and the health of consumers. At the same time the country has made significant public and private investments in the field that allowed the country to obtain a leading position in biosafety in the region and genetic engineering research at national research centers. Any attempt to restrict or prohibit these activities in the country, will put in risk the previously described investment, will affect the generation of new knowledge for decision making and the leadership in the field, preventing the benefits derived from this promising technology.

  18. Genetically modified crops and aquatic ecosystems: considerations for environmental risk assessment and non-target organism testing.

    PubMed

    Carstens, Keri; Anderson, Jennifer; Bachman, Pamela; De Schrijver, Adinda; Dively, Galen; Federici, Brian; Hamer, Mick; Gielkens, Marco; Jensen, Peter; Lamp, William; Rauschen, Stefan; Ridley, Geoff; Romeis, Jörg; Waggoner, Annabel

    2012-08-01

    Environmental risk assessments (ERA) support regulatory decisions for the commercial cultivation of genetically modified (GM) crops. The ERA for terrestrial agroecosystems is well-developed, whereas guidance for ERA of GM crops in aquatic ecosystems is not as well-defined. The purpose of this document is to demonstrate how comprehensive problem formulation can be used to develop a conceptual model and to identify potential exposure pathways, using Bacillus thuringiensis (Bt) maize as a case study. Within problem formulation, the insecticidal trait, the crop, the receiving environment, and protection goals were characterized, and a conceptual model was developed to identify routes through which aquatic organisms may be exposed to insecticidal proteins in maize tissue. Following a tiered approach for exposure assessment, worst-case exposures were estimated using standardized models, and factors mitigating exposure were described. Based on exposure estimates, shredders were identified as the functional group most likely to be exposed to insecticidal proteins. However, even using worst-case assumptions, the exposure of shredders to Bt maize was low and studies supporting the current risk assessments were deemed adequate. Determining if early tier toxicity studies are necessary to inform the risk assessment for a specific GM crop should be done on a case by case basis, and should be guided by thorough problem formulation and exposure assessment. The processes used to develop the Bt maize case study are intended to serve as a model for performing risk assessments on future traits and crops.

  19. Effects of glyphosate-resistant crop cultivation on soil and water quality.

    PubMed

    Cerdeira, Antonio L; Duke, Stephen O

    2010-01-01

    Transgenic glyphosate-resistant crops (GRCs) have been commercialized and grown extensively in the Western Hemisphere and, to a lesser extent, elsewhere. GRCs have generally become dominant in those countries where they have been approved for growing. Potential effects of glyphosate on soil and water are minimal, compared the effects of the herbicides that are replaced when GRCs are adopted. Perhaps the most important indirect effect is that GRCs crops promote the adoption of reduced- or no-tillage agriculture, resulting in a significant reduction in soil erosion and water contamination. Glyphosate and its degradation product, aminomethylphosphonate (AMPA), residues are not usually detected in high levels in ground or surface water in areas where glyphosate is used extensively.  Furthermore, both glyphosate and AMPA are considered to be much more toxicologically and environmentally benign than most of the herbicides replaced by glyphosate.

  20. Performance and cross-crop resistance of Cry1F-maize selected Spodoptera frugiperda on transgenic Bt cotton: implications for resistance management

    PubMed Central

    Yang, Fei; Kerns, David L.; Brown, Sebe; Kurtz, Ryan; Dennehy, Tim; Braxton, Bo; Head, Graham; Huang, Fangneng

    2016-01-01

    Transgenic crops producing Bacillus thuringiensis (Bt) proteins have become a primary tool in pest management. Due to the intensive use of Bt crops, resistance of the fall armyworm, Spodoptera frugiperda, to Cry1F maize has occurred in Puerto Rico, Brazil, and some areas of the southeastern U.S. The sustainability of Bt crops faces a great challenge because the Cry1F-maize resistant S. frugiperda may also infest other Bt crops in multiple cropping ecosystems. Here we examined the survival and plant injury of a S. frugiperda population selected with Cry1F maize on three single-gene and five pyramided Bt cotton products. Larvae of Cry1F-susceptible (SS), -heterozygous (RS), and -resistant (RR) genotypes of S. frugiperda were all susceptible to the pyramided cotton containing Cry1Ac/Cry2Ab, Cry1Ac/Cry1F/Vip3A, Cry1Ab/Cry2Ae, or Cry1Ab/Cry2Ae/Vip3A, and the single-gene Cry2Ae cotton. Pyramided cotton containing Cry1Ac/Cry1F was effective against SS and RS, but not for RR. These findings show that the Cry1F-maize selected S. frugiperda can cause cross-crop resistance to other Bt crops expressing similar insecticidal proteins. Resistance management and pest management programs that utilize diversify mortality factors must be implemented to ensure the sustainability of Bt crops. This is especially important in areas where resistance to single-gene Bt crops is already widespread. PMID:27301612

  1. Performance and cross-crop resistance of Cry1F-maize selected Spodoptera frugiperda on transgenic Bt cotton: implications for resistance management.

    PubMed

    Yang, Fei; Kerns, David L; Brown, Sebe; Kurtz, Ryan; Dennehy, Tim; Braxton, Bo; Head, Graham; Huang, Fangneng

    2016-06-15

    Transgenic crops producing Bacillus thuringiensis (Bt) proteins have become a primary tool in pest management. Due to the intensive use of Bt crops, resistance of the fall armyworm, Spodoptera frugiperda, to Cry1F maize has occurred in Puerto Rico, Brazil, and some areas of the southeastern U.S. The sustainability of Bt crops faces a great challenge because the Cry1F-maize resistant S. frugiperda may also infest other Bt crops in multiple cropping ecosystems. Here we examined the survival and plant injury of a S. frugiperda population selected with Cry1F maize on three single-gene and five pyramided Bt cotton products. Larvae of Cry1F-susceptible (SS), -heterozygous (RS), and -resistant (RR) genotypes of S. frugiperda were all susceptible to the pyramided cotton containing Cry1Ac/Cry2Ab, Cry1Ac/Cry1F/Vip3A, Cry1Ab/Cry2Ae, or Cry1Ab/Cry2Ae/Vip3A, and the single-gene Cry2Ae cotton. Pyramided cotton containing Cry1Ac/Cry1F was effective against SS and RS, but not for RR. These findings show that the Cry1F-maize selected S. frugiperda can cause cross-crop resistance to other Bt crops expressing similar insecticidal proteins. Resistance management and pest management programs that utilize diversify mortality factors must be implemented to ensure the sustainability of Bt crops. This is especially important in areas where resistance to single-gene Bt crops is already widespread.

  2. Key global environmental impacts of genetically modified (GM) crop use 1996-2012.

    PubMed

    Barfoot, Peter; Brookes, Graham

    2014-01-01

    Against the background of increasing awareness and appreciation of issues such as global warming and the impact of mankind's activities such as agriculture on the global environment, this paper updates previous assessments of some key environmental impacts that crop biotechnology has had on global agriculture. It focuses on the environmental impacts associated with changes in pesticide use and greenhouse gas emissions arising from the use of GM crops. The adoption of the technology has reduced pesticide spraying by 503 million kg (-8.8%) and, as a result, decreased the environmental impact associated with herbicide and insecticide use on these crops (as measured by the indicator the Environmental Impact Quotient [EIQ]) by 18.7%. The technology has also facilitated a significant reduction in the release of greenhouse gas emissions from this cropping area, which, in 2012, was equivalent to removing 11.88 million cars from the roads.

  3. Key environmental impacts of global genetically modified (GM) crop use 1996-2011.

    PubMed

    Brookes, Graham; Barfoot, Peter

    2013-01-01

    Given the increasing awareness and appreciation of issues such as global warming and the impact of mankind's activities such as agriculture on the global environment, this paper updates previous assessments of the environmental impact of an important and relatively new technology, crop biotechnology has had on global agriculture. It focuses on the environmental impacts associated with changes in pesticide use and greenhouse gas emissions arising from the use of GM crops. The adoption of the technology has reduced pesticide spraying by 474 million kg (-8.9%) and, as a result, decreased the environmental impact associated with herbicide and insecticide use on these crops [as measured by the indicator the Environmental Impact Quotient (EIQ)] by 18.1%. The technology has also facilitated a significant reduction in the release of greenhouse gas emissions from this cropping area, which, in 2011, was equivalent to removing 10.22 million cars from the roads.

  4. Key global environmental impacts of genetically modified (GM) crop use 1996–2012

    PubMed Central

    Barfoot, Peter; Brookes, Graham

    2014-01-01

    Against the background of increasing awareness and appreciation of issues such as global warming and the impact of mankind’s activities such as agriculture on the global environment, this paper updates previous assessments of some key environmental impacts that crop biotechnology has had on global agriculture. It focuses on the environmental impacts associated with changes in pesticide use and greenhouse gas emissions arising from the use of GM crops. The adoption of the technology has reduced pesticide spraying by 503 million kg (-8.8%) and, as a result, decreased the environmental impact associated with herbicide and insecticide use on these crops (as measured by the indicator the Environmental Impact Quotient [EIQ]) by 18.7%. The technology has also facilitated a significant reduction in the release of greenhouse gas emissions from this cropping area, which, in 2012, was equivalent to removing 11.88 million cars from the roads. PMID:24637726

  5. Solutions Network Formulation Report. Using NASA Sensors to Perform Crop Type Assessment for Monitoring Insect Resistance in Corn

    NASA Technical Reports Server (NTRS)

    Lewis, David; Copenhaver, Ken; Anderson, Daniel; Hilbert, Kent

    2007-01-01

    The EPA (U.S. Environmental Protection Agency) is tasked to monitor for insect pest resistance to transgenic crops. Several models have been developed to understand the resistance properties of insects. The Population Genetics Simulator model is used in the EPA PIRDSS (Pest Infestation and Resistance Decision Support System). The EPA Office of Pesticide Programs uses the DSS to help understand the potential for insect pest resistance development and the likelihood that insect pest resistance will negatively affect transgenic corn. Once the DSS identifies areas of concern, crews are deployed to collect insect pest samples, which are tested to identify whether they have developed resistance to the toxins in transgenic corn pesticides. In this candidate solution, VIIRS (Visible/Infrared Imager/Radiometer Suite) vegetation index products will be used to build hypertemporal layerstacks for crop type and phenology assessment. The current phenology attribute is determined by using the current time of year to index the expected growth stage of the crop. VIIRS might provide more accurate crop type assessment and also might give a better estimate on the crop growth stage.

  6. Genetically modified and organic crops in developing countries: a review of options for food security.

    PubMed

    Azadi, Hossein; Ho, Peter

    2010-01-01

    Since two decades ago, when the first GM crops were introduced, there have increasingly been hot debates on the applications of gene manipulation. Currently, the development of GM crop varieties has raised a wide range of new legal, ethical and economic questions in agriculture. There is a growing body of literature reflecting the socio-economic and environmental impacts of GM crops which aims to criticize their value for farming systems. While organic crops are promoted as environmentally-friendly products in developed countries, they have provoked great controversy in developing countries facing food security and a low agricultural productivity. Discussion has been especially vigorous when organic farming was introduced as an alternative method. There are in fact, a few tradeoffs in developing countries. On the one hand, farmers are encouraged to accept and implement GM crops because of their higher productivity, while on the other hand, organic farming is encouraged because of socio-economic and environmental considerations. A crucial question facing such countries is therefore, whether GM crops can co-exist with organic farming. This paper aims to review the main considerations and tradeoffs.

  7. Glyphosate degradation in glyphosate-resistant and -susceptible crops and weeds.

    PubMed

    Duke, Stephen O

    2011-06-08

    High levels of aminomethylphosphonic acid (AMPA), the main glyphosate metabolite, have been found in glyphosate-treated, glyphosate-resistant (GR) soybean, apparently due to plant glyphosate oxidoreductase (GOX)-like activity. AMPA is mildly phytotoxic, and under some conditions the AMPA accumulating in GR soybean correlates with glyphosate-caused phytotoxicity. A bacterial GOX is used in GR canola, and an altered bacterial glyphosate N-acetyltransferase is planned for a new generation of GR crops. In some weed species, glyphosate degradation could contribute to natural resistance. Neither an isolated plant GOX enzyme nor a gene for it has yet been reported in plants. Gene mutation or amplification of plant genes for GOX-like enzyme activity or horizontal transfer of microbial genes from glyphosate-degrading enzymes could produce GR weeds. Yet, there is no evidence that metabolic degradation plays a significant role in evolved resistance to glyphosate. This is unexpected, considering the extreme selection pressure for evolution of glyphosate resistance in weeds and the difficulty in plants of evolving glyphosate resistance via other mechanisms.

  8. Transportability of confined field trial data from cultivation to import countries for environmental risk assessment of genetically modified crops.

    PubMed

    Nakai, Shuichi; Hoshikawa, Kana; Shimono, Ayako; Ohsawa, Ryo

    2015-12-01

    Requirement of in-country confined field trials for genetically modified (GM) crops prior to unrestricted release is well-established among countries with domestic regulations for the cultivation approval of GM crops. However, the requirement of in-country confined field trials is not common in countries where the scope of the application does not include cultivation. Nonetheless, Japan and China request in-country confined field trials for GM crops which are intended only for use as food, feed and processing. This paper considers the transportability of confined field trial data from cultivation countries (e.g. United States, Canada, and South American countries) to import countries like Japan for the environmental risk assessment of GM crops by reviewing: (1) the purpose of confined field trial assessment, (2) weediness potential, defined as "an ability to establish and persist in an unmanaged area that is frequently disturbed by human activity", of host crops, and (3) reliability of the confined field trial data obtained from cultivation countries. To review the reliability of the confined field data obtained in the US, this paper describes actual examples of three confined field trials of approved GM corn events conducted both in the US and Japan. Based on the above considerations, this paper concludes that confined field data of GM corn and cotton is transportable from cultivation countries to importing countries (e.g. from the US to Japan), regardless of the characteristics of the inserted gene(s). In addition, this paper advocates harmonization of protocols for confined field trials to facilitate more efficient data transportability across different geographies.

  9. Concentrated polymer brush-modified silica particle coating confers biofouling-resistance on modified materials.

    PubMed

    Yoshikawa, Chiaki; Qiu, Jun; Shimizu, Yoshihisa; Huang, Chih-Feng; Gelling, Onko-Jan; van den Bosch, Edith

    2017-01-01

    Biofouling, an undesired adsorption of biological material to otherwise inert surfaces, is detrimental in medical, pharmaceutical, and other sectors. Concentrated polymer brushes (CPB) confer non-biofouling properties on modified surfaces but are cumbersome to fabricate. Here, a simple and versatile method of fabricating non-biofouling coatings for various substrates was developed using CPB-modified silica nanoparticles (SiPs). Concentrated poly(poly(ethylene glycol) methyl ether methacrylate) (PPEGMA) brushes were grafted on SiPs by surface-initiated atom transfer radical polymerization. CPB-SiPs were spin-coated onto silicon wafers or quartz crystal microbalance (QCM) sensor chips with phenyl azido cross-linkers. SiP cross-linking was then performed by ultra violet irradiation for 20s, or by heating at 120°C for 12h. Protein adsorption to coatings was studied by QCM approach and human umbilical vein endothelial cell adhesion to coatings was examined. SiP to cross-linker weight ratios were varied from 2.0/0.5 to 9.0/0.5 (wt/wt%) and the coatings almost completely suppressed protein adsorption and cell adhesion to treated surfaces. The coating was also applied to polymeric films, rendering these materials biofouling-resistant.

  10. Debates on Genetically Modified Crops in the Context of Sustainable Development.

    PubMed

    Gerasimova, Ksenia

    2016-04-01

    The paper discusses conflicts in perceptions of GM crops illustrating the complexities of GM debates and applications of the concept of sustainable development. The concept consists of three discourses that both opponents and supporters of GM crops refer to in their analyses: environmentalism, social and economic development and the two sub-issues of sustainable development-biodiversity loss and food security. This creates a unique situation when both proponents and opponents of GM food use the same framework of sustainable development to support their arguments and do not reach a common ground. This will be illustrated by a review of the arguments brought by these two groups.

  11. The Development of a Remote Sensor System and Decision Support Systems Architecture to Monitor Resistance Development in Transgenic Crops

    NASA Technical Reports Server (NTRS)

    Cacas, Joseph; Glaser, John; Copenhaver, Kenneth; May, George; Stephens, Karen

    2008-01-01

    The United States Environmental Protection Agency (EPA) has declared that "significant benefits accrue to growers, the public, and the environment" from the use of transgenic pesticidal crops due to reductions in pesticide usage for crop pest management. Large increases in the global use of transgenic pesticidal crops has reduced the amounts of broad spectrum pesticides used to manage pest populations, improved yield and reduced the environmental impact of crop management. A significant threat to the continued use of this technology is the evolution of resistance in insect pest populations to the insecticidal Bt toxins expressed by the plants. Management of transgenic pesticidal crops with an emphasis on conservation of Bt toxicity in field populations of insect pests is important to the future of sustainable agriculture. A vital component of this transgenic pesticidal crop management is establishing the proof of concept basic understanding, situational awareness, and monitoring and decision support system tools for more than 133650 square kilometers (33 million acres) of bio-engineered corn and cotton for development of insect resistance . Early and recent joint NASA, US EPA and ITD remote imagery flights and ground based field experiments have provided very promising research results that will potentially address future requirements for crop management capabilities.

  12. Development of agricultural biotechnology and biosafety regulations used to assess the safety of genetically modified crops in Iran.

    PubMed

    Mousavi, Amir; Malboobi, Mohammad A; Esmailzadeh, Nasrin S

    2007-01-01

    Rapid progress in the application of biotechnological methodologies and development of genetically modified crops in Iran necessitated intensive efforts to establish proper organizations and prepare required rules and regulations at the national level to ensure safe application of biotechnology in all pertinent aspects. Practically, preparation of a national biotechnology strategic plan in the country coincided with development of a national biosafety framework that was the basis for the drafted biosafety law. Although biosafety measures were observed by researchers voluntarily, the establishment of national biosafety organizations since the year 2000 built a great capacity to deal with biosafety issues in the present and future time, particularly with respect to food and agricultural biotechnology.

  13. Surface resistance measurement of modified QMG superconducting bulks

    NASA Astrophysics Data System (ADS)

    Saito, A.; Sekiya, N.; Teshima, H.; Obara, H.; Noguchi, Y.; Hirano, H.; Hirano, S.; Ohshima, S.

    2006-10-01

    We investigated the microwave properties of high-temperature superconductor (HTS) bulks for high-power microwave applications. The HTS bulk samples of Dy-Ba-Cu-O and Gd-Ba-Cu-O, were prepared using the modified quench and melt growth (QMG) process. The relationship among the bulk surface mirror polishing process, oxygen annealing process, and surface resistance (Rs) was also investigated. The Rs of the HTS bulks was measured using the dielectric resonator method at 21.8 GHz for the TE011 mode. The measurement temperature was varied from 20 to 95 K. We found that the annealing after surface mirror polishing was more effective to obtain low Rs than polishing after annealing. Although the Rs value of the optimized Dy-Ba-Cu-O bulk sample at 20 K was twofold larger than that of the high-quality YBa2Cu3O7-δ thin film fabricated by THEVA GmbH, the Rs value was even low enough to be used for microwave devices. These results indicate that Dy-Ba-Cu-O bulk superconductors are feasible for applications to high-power transmit filters for mobile communication systems.

  14. Strategies to protect crop plants against viruses: pathogen-derived resistance blossoms.

    PubMed Central

    Wilson, T M

    1993-01-01

    Since 1986, the ability to confer resistance against an otherwise devastating virus by introducing a single pathogen-derived or virus-targeted sequence into the DNA of a potential host plant has had a marked influence on much of the research effort, focus, and short-term objectives of plant virologists throughout the world. The vast literature on coat protein-mediated protection, for example, attests to our fascination for unraveling fundamental molecular mechanism(s), our (vain) search for a unifying hypothesis, our pragmatic interest in commercially exploitable opportunities for crop protection, and our ingenuity in manipulating transgene constructions to broaden their utility and reduce real or perceived environmental risk issues. Other single dominant, pathogen-derived plant resistance genes have recently been discovered from a wide variety of viruses and are operative in an ever-increasing range of plant species. Additional candidates seem limited only by the effort invested in experimentation and by our ingenuity and imagination. This review attempts to consider, in a critical way, the current state of the art, some exceptions, and some proposed rules. The final impression, from all the case evidence considered, is that normal virus replication requires a subtle blend of host- and virus-coded proteins, present in critical relative concentrations and at specific times and places. Any unregulated superimposition of interfering protein or nucleic acid species can, therefore, result in an apparently virus-resistant plant phenotype. PMID:8475051

  15. Evolution of Resistance by Helicoverpa zea (Lepidoptera: Noctuidae) Infesting Insecticidal Crops in the Southern United States

    PubMed Central

    Onstad, David; Crain, Philip; Crespo, Andre; Hutchison, William; Buntin, David; Porter, Pat; Catchot, Angus; Cook, Don; Pilcher, Clint; Flexner, Lindsey; Higgins, Laura

    2016-01-01

    We created a deterministic, frequency-based model of the evolution of resistance by corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), to insecticidal traits expressed in crops planted in the heterogeneous landscapes of the southern United States. The model accounts for four generations of selection by insecticidal traits each year. We used the model results to investigate the influence of three factors on insect resistance management (IRM): 1) how does adding a third insecticidal trait to both corn and cotton affect durability of the products, 2) how does unstructured corn refuge influence IRM, and 3) how do block refuges (50% compliance) and blended refuges compare with regard to IRM? When Bt cotton expresses the same number of insecticidal traits, Bt corn with three insecticidal traits provides longer durability than Bt corn with two pyramided traits. Blended refuge provides similar durability for corn products compared with the same level of required block refuge when the rate of refuge compliance by farmers is 50%. Results for Mississippi and Texas are similar, but durabilities for corn traits are surprisingly lower in Georgia, where unstructured corn refuge is the highest of the three states, but refuge for Bt cotton is the lowest of the three states. Thus, unstructured corn refuge can be valuable for IRM but its influence is determined by selection for resistance by Bt cotton. PMID:26637533

  16. Perceived Consequences of Herbicide-Tolerant and Insect-Resistant Crops on Integrated Pest Management Strategies in the Western United States: Results of an Online Survey

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We conducted an online survey to assess the potential effects of herbicide-tolerant (HT) and insect-resistant (IR) crops on integrated pest management (IPM) practices in the Western United States. For HT crops, participants perceived a decrease in several IPM practices, including crop and herbicide ...

  17. Chemical control of perennial and annual weeds in herbicide resistant soybean crops.

    PubMed

    Sarpe, N; Roibu, C; Negrila, E; Bodescu, F; Fuia, S; Popa, C; Beraru, C

    2001-01-01

    In Romania, the first tests with Roundup Ready on soybean crops were performed in 1998, on 2 soil types: a) at Teleorman Station on chernozem containing 3.5% humus, 4.5% clay b) at Brăila Station placed in Danube Meadow on alluvial soil containing 3.90% humus and 46% clay. In every locality cultivated soybean cultivar S.2254 was resistant to glyphosate. During the three years of experiments (1998-2000) the crop of soybean was infested with various species of weeds (both annual and perennial) of which the most important are: Sorghum halepense (60-80%), Echinochloa crus-galli, Setaria glauca, Amaranthus retroflexus, Solarium nigrum, Yanthium italicum, Abutilon theoprasthi, Sinapis arvensis, Datum stramonium, Polygonum persicaria, Calystegia sepium, Cirsium arvense. In 3 years of experience the best weed control and the highest soybean production were obtained in the variants treated 2 times postemergent with Roundup Ready at a dose of 3 + 3 l/ha. Similar results were also obtained in the farms of the Academy of Agricultural Forestry Sciences, where GMO soybean was cultivated on 1500 hectares.

  18. Resistance Evolution to Bt Crops: Predispersal Mating of European Corn Borers

    PubMed Central

    Dalecky, Ambroise; Ponsard, Sergine; Bailey, Richard I; Pélissier, Céline; Bourguet, Denis

    2006-01-01

    Over the past decade, the high-dose refuge (HDR) strategy, aimed at delaying the evolution of pest resistance to Bacillus thuringiensis (Bt) toxins produced by transgenic crops, became mandatory in the United States and is being discussed for Europe. However, precopulatory dispersal and the mating rate between resident and immigrant individuals, two features influencing the efficiency of this strategy, have seldom been quantified in pests targeted by these toxins. We combined mark-recapture and biogeochemical marking over three breeding seasons to quantify these features directly in natural populations of Ostrinia nubilalis, a major lepidopteran corn pest. At the local scale, resident females mated regardless of males having dispersed beforehand or not, as assumed in the HDR strategy. Accordingly, 0–67% of resident females mating before dispersal did so with resident males, this percentage depending on the local proportion of resident males (0% to 67.2%). However, resident males rarely mated with immigrant females (which mostly arrived mated), the fraction of females mating before dispersal was variable and sometimes substantial (4.8% to 56.8%), and there was no evidence for male premating dispersal being higher. Hence, O. nubilalis probably mates at a more restricted spatial scale than previously assumed, a feature that may decrease the efficiency of the HDR strategy under certain circumstances, depending for example on crop rotation practices. PMID:16719560

  19. Weeds in fields with contrasting conventional and genetically modified herbicide-tolerant crops. I. Effects on abundance and diversity.

    PubMed Central

    Heard, M S; Hawes, C; Champion, G T; Clark, S J; Firbank, L G; Haughton, A J; Parish, A M; Perry, J N; Rothery, P; Scott, R J; Skellern, M P; Squire, G R; Hill, M O

    2003-01-01

    We compared the seedbanks, seed rains, plant densities and biomasses of weeds under two contrasting systems of management in beet, maize and spring oilseed rape. Weed seedbank and plant density were measured at the same locations in two subsequent seasons. About 60 fields were sown with each crop. Each field was split, one half being sown with a conventional variety managed according to the farmer's normal practice, the other half being sown with a genetically modified herbicide-tolerant (GMHT) variety, with weeds controlled by a broad-spectrum herbicide. In beet and rape, plant densities shortly after sowing were higher in the GMHT treatment. Following weed control in conventional beet, plant densities were approximately one-fifth of those in GMHT beet. In both beet and rape, this effect was reversed after the first application of broad-spectrum herbicide, so that late-season plant densities were lower in the GMHT treatments. Biomass and seed rain in GMHT crops were between one-third and one-sixth of those in conventional treatments. The effects of differing weed-seed returns in these two crops persisted in the seedbank: densities following the GMHT treatment were about 20% lower than those following the conventional treatment. The effect of growing maize was quite different. Weed density was higher throughout the season in the GMHT treatment. Late-season biomass was 82% higher and seed rain was 87% higher than in the conventional treatment. The difference was not subsequently detectable in the seedbank because the total seed return was low after both treatments. In all three crops, weed diversity was little affected by the treatment, except for transient effects immediately following herbicide application. PMID:14561316

  20. On the rationale and interpretation of the Farm Scale Evaluations of genetically modified herbicide-tolerant crops.

    PubMed Central

    Squire, G R; Brooks, D R; Bohan, D A; Champion, G T; Daniels, R E; Haughton, A J; Hawes, C; Heard, M S; Hill, M O; May, M J; Osborne, J L; Perry, J N; Roy, D B; Woiwod, I P; Firbank, L G

    2003-01-01

    Farmland biodiversity and food webs were compared in conventional and genetically modified herbicide-tolerant (GMHT) crops of beet (Beta vulgaris L.), maize (Zea mays L.) and both spring and winter oilseed rape (Brassica napus L.). GMHT and conventional varieties were sown in a split-field experimental design, at 60-70 sites for each crop, spread over three starting years beginning in 2000. This paper provides a background to the study and the rationale for its design and interpretation. It shows how data on environment, field management and the biota are used to assess the current state of the ecosystem, to define the typical arable field and to devise criteria for selecting, sampling and auditing experimental sites in the Farm Scale Evaluations. The main functional and taxonomic groups in the habitat are ranked according to their likely sensitivity to GMHT cropping, and the most responsive target organisms are defined. The value of the seedbank as a baseline and as an indicator of historical trends is proposed. Evidence from experiments during the twentieth century is analysed to show that large changes in field management have affected sensitive groups in the biota by ca. 50% during a year or short run of years--a figure against which to assess any positive or negative effects of GMHT cropping. The analysis leads to a summary of factors that were, and were not, examined in the first 3 years of the study and points to where modelling can be used to extrapolate the effects to the landscape and the agricultural region. PMID:14561314

  1. Rootworm Management with Genetically Modified Corn: Current Status, Potential for Resistance, and a Look Toward the Future

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To delay evolution of insect resistance to transgenic crops producing Bacillus thuringiensis (Bt) toxins, nearby "refuges" of host plants not producing Bt toxins are required in many regions. Such refuges are expected to be most effective in slowing resistance when the toxin concentration in Bt crop...

  2. Prioritizing stream types according to their potential risk to receive crop plant material--A GIS-based procedure to assist in the risk assessment of genetically modified crops and systemic insecticide residues.

    PubMed

    Bundschuh, Rebecca; Kuhn, Ulrike; Bundschuh, Mirco; Naegele, Caroline; Elsaesser, David; Schlechtriemen, Ulrich; Oehen, Bernadette; Hilbeck, Angelika; Otto, Mathias; Schulz, Ralf; Hofmann, Frieder

    2016-03-15

    Crop plant residues may enter aquatic ecosystems via wind deposition or surface runoff. In the case of genetically modified crops or crops treated with systemic pesticides, these materials may contain insecticidal Bt toxins or pesticides that potentially affect aquatic life. However, the particular exposure pattern of aquatic ecosystems (i.e., via plant material) is not properly reflected in current risk assessment schemes, which primarily focus on waterborne toxicity and not on plant material as the route of uptake. To assist in risk assessment, the present study proposes a prioritization procedure of stream types based on the freshwater network and crop-specific cultivation data using maize in Germany as a model system. To identify stream types with a high probability of receiving crop materials, we developed a formalized, criteria-based and thus transparent procedure that considers the exposure-related parameters, ecological status--an estimate of the diversity and potential vulnerability of local communities towards anthropogenic stress--and availability of uncontaminated reference sections. By applying the procedure to maize, ten stream types out of 38 are expected to be the most relevant if the ecological effects from plant-incorporated pesticides need to be evaluated. This information is an important first step to identifying habitats within these stream types with a high probability of receiving crop plant material at a more local scale, including accumulation areas. Moreover, the prioritization procedure developed in the present study may support the selection of aquatic species for ecotoxicological testing based on their probability of occurrence in stream types having a higher chance of exposure. Finally, this procedure can be adapted to any geographical region or crop of interest and is, therefore, a valuable tool for a site-specific risk assessment of crop plants carrying systemic pesticides or novel proteins, such as insecticidal Bt toxins, expressed

  3. Functionality of Varroa-Resistant Honey Bees (Hymenoptera: Apidae) When Used in Migratory Beekeeping for Crop Pollination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two types of honey bees, Apis mellifera L., that were bred for resistance to Varroa destructor Anderson & Trueman were evaluated for performance when used for beekeeping in an intensive, migratory crop pollination system. Colonies of these stocks (Russian honey bees [RHB] and outcrosses of bees with...

  4. Risk assessment of genetically engineered crops: fitness effects of virus-resistance transgenes in wild Cucurbita pepo.

    PubMed

    Laughlin, Karen D; Power, Alison G; Snow, Allison A; Spencer, Lawrence J

    2009-07-01

    The development of crops genetically engineered for pathogen resistance has raised concerns that crop-to-wild gene flow could release wild or weedy relatives from regulation by the pathogens targeted by the transgenes that confer resistance. Investigation of these risks has also raised questions about the impact of gene flow from conventional crops into wild plant populations. Viruses in natural plant populations can play important roles in plant fecundity and competitive interactions. Here, we show that virus-resistance transgenes and conventional crop genes can increase fecundity of wild plants under virus pressure. We asked how gene flow from a cultivated squash (Cucurbita pepo) engineered for virus resistance would affect the fecundity of wild squash (C. pepo) in the presence and absence of virus pressure. A transgenic squash cultivar was crossed and backcrossed with wild C. pepo from Arkansas. Wild C. pepo, transgenic backcross plants, and non-transgenic backcross plants were compared in field plots in Ithaca, New York, USA. The second and third generations of backcrosses (BC2 and BC3) were used in 2002 and 2003, respectively. One-half of the plants were inoculated with zucchini yellow mosaic virus (ZYMV), and one-half of the plants were maintained as healthy controls. Virus pressure dramatically decreased the fecundity of wild C. pepo plants and non-transgenic backcross plants relative to transgenic backcross plants, which showed continued functioning of the virus-resistance transgene. In 2002, non-transgenic backcross fecundity was slightly higher than wild C. pepo fecundity under virus pressure, indicating a possible benefit of conventional crop alleles, but they did not differ in 2003 when fecundity was lower in both groups. We detected no fitness costs of the transgene in the absence of the virus. If viruses play a role in the population dynamics of wild C. pepo, we predict that gene flow from transgenic, virus-resistant squash and, to a much lesser

  5. Advances in improvement of quality and resistance in a multipurpose crop: sea buckthorn.

    PubMed

    Ruan, Cheng-Jiang; Rumpunen, Kimmo; Nybom, Hilde

    2013-06-01

    Sea buckthorn is a berry crop with multiple uses. The berries are highly appreciated for their unique taste but are also very rich in bioactive compounds with powerful nutritional and medicinal values. In addition, the plants grow well under adverse conditions, and are often used to fight soil erosion. Utilization of sea buckthorn has therefore increased around the world but serious problems have, nevertheless, been encountered due to drought, salinity, diseases and insect pests. This review covers important aspects of sea buckthorn research, such as heritable and environmentally induced variation in biochemical compounds, causes and effects of the devastating dried-shrink disease, susceptibility to insect pests, methods for conventional breeding, and the utilization of DNA markers for taxonomical and population genetic analyses, and for investigating the inheritance of quality and resistance traits. We also present possibilities to implement innovative biotechnological breeding methods, especially metabolite profiling and MAS/GRC-based markers, for fast and efficient development of elite genotypes with specific nutritional- and health-related bioactive compounds and strong resistance to biotic and abiotic stress.

  6. Prevalence of plasmid mediated pesticide resistant bacterial assemblages in crop fields.

    PubMed

    Umamaheswari, S; Murali, M

    2010-11-01

    Three crop fields namely paddy sugarcane and tomato exposed to bavistin [Methyl (1H-benzimidazol-2-yl) carbomate], monocrotophos[Dimethyl(E)-1-methyl-2-(methyl-carbamoyl) vinyl phosphate] and kinado plus [(EZ)-2-chloro-3-dimethoxyphosphinoyloxy-X1, X1-diethylbut-2-enamide], respectively were chosen for the present investigation to know the bacterial population and degradation of pesticides. The chemical nature of the soil and water samples from the pesticide contaminated fields was analysed along with counting of the total heterotrophic bacteria (THB), Staphylococci and Enterococcci population. Mean calcium, phosphate and biological oxygen demand were maximum in tomato field water Field water recorded maximum phophate and silicate content, whereas, sugarcane field water elicited maximum dissolved oxygen content. On the other hand, available phosphate and exchangeable potassium were maximum is sugarcane field soil. Significant variations in the bacterial population were evident between the treatments in sugarcane field soil and tomato field water exposed to monocrotophos and kinado plus, respectively In addition, significant variations between THB, Staphlyococci and Enterococci population were also evinced in both the sugarcane andtomato fields. The dominant pesticide resistant bacteria, Staphylococcus aureus, Enterococcus faecalis and Pseudomonas aeuroginosa harboured plasmids and the resistant trait observed were found to be plasmid borne.

  7. Compositional analysis of genetically modified (GM) crops: key issues and future needs.

    PubMed

    Hoekenga, Owen A; Srinivasan, Jannavi; Barry, Gerard; Bartholomaeus, Andrew

    2013-09-04

    Effective symposia need two strong legs to stand upon: informative presentations of recent research paired with lively discussion of these topics. Although it is easy for the organizers of a symposium to predict the usefulness of the former, as they select the speakers and their topic areas, guaranteeing productive discussion is a far more difficult task. For the Crop Composition Workshop sponsored by the International Life Sciences Institute's Committee on Food and Biotechnology (ILSI IFBIC), the organizers scheduled four roundtable discussions with preselected questions and with rapporteurs drawn from governmental organizations and public-sector research institutes (the authors). It was also the organizers' intent to let these discussions flow on the basis of the experiences of the participants and pressing issues within the overall debate on the role of crop compositional analysis within safety assessment of biotechnology as it exists now and in the future. The goal of this perspective is to summarize the issues raised, providing references when possible, and to describe the consensus statements reached through the course of these discussions.

  8. Model-based tolerance intervals derived from cumulative historical composition data: application for substantial equivalence assessment of a genetically modified crop.

    PubMed

    Hong, Bonnie; Fisher, Tracey L; Sult, Theresa S; Maxwell, Carl A; Mickelson, James A; Kishino, Hirohisa; Locke, Mary E H

    2014-10-08

    Compositional analysis is a requisite component of the substantial equivalence framework utilized to assess genetically modified (GM) crop safety. Statistical differences in composition data between GM and non-GM crops require a context in which to determine biological relevance. This context is provided by surveying the natural variation of key nutrient and antinutrient levels within the crop population with a history of safe use. Data accumulated from various genotypes with a history of safe use cultivated in relevant commercial crop-growing environments over multiple seasons are discussed as the appropriate data representative of this natural variation. A model-based parametric tolerance interval approach, which accounts for the correlated and unbalanced data structure of cumulative historical data collected from multisite field studies conducted over multiple seasons, is presented. This paper promotes the application of this tolerance interval approach to generate reference ranges for evaluation of the biological relevance of statistical differences identified during substantial equivalence assessment of a GM crop.

  9. Genetic basis and detection of unintended effects in genetically modified crop plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In January 2014, an international meeting sponsored by the International Life Sciences Institute/Health and Environmental Sciences Institute and the Canadian Food Inspection Agency titled “Genetic Basis of Unintended Effects in Modified Plants” was held in Ottawa, Canada, bringing together over 75 s...

  10. Advances in managing pest resistance to Bt crops: Pyramids and seed mixtures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transgenic crops producing toxins from the soil bacterium Bacillus thuringiensis (Bt) have been widely used for the control of insect pests during the last 20 years. Although Bt crops have provided significant environmental and economic benefits, sustainable use of these crops is threatened by the r...

  11. Accelerating adoption of genetically modified crops in Africa through a trade liability regime.

    PubMed

    Smyth, Stuart J; Kerr, William A; Phillips, Peter W B

    2013-06-01

    Given the apparently unbridgeable divide that has developed between the 25 odd countries that grow and trade GM crops and the evolving EU regulatory hurdles, it may be time to consider alternative strategies for realizing a global market for agricultural products. Africa is one area of the world where the battle over GM agriculture is being played out, yet it is the continent where GM could have the greatest positive impact. Numerous African nations, given their long-standing trade connections to European nations, fear that allowing the commercialization of GM crops could lead to comingling of GM and conventional products and, hence, the loss of export opportunities to the EU. These are legitimate concerns. One potential solution that warrants serious consideration would be to establish a pool of funds that could be accessed by African agricultural commodity exporters in instances where exports to Europe are rejected. A production levy could be imposed in leading industrial adopting nations (i.e., Australia, Canada and the United States). The revenue raised would provide an endowment fund that could be used to offset the costs arising from import refusals. African-sourced shipments rejected by the EU will most certainly have alternate markets, but could receive a reduced price or incur higher costs associated with serving alternate markets. The intent of the fund would be to compensate for the real difference between the net returns contracted with European importers and the final market price received. This article examines the feasibility of establishing such a fund and discusses the funding options.

  12. Simulation of collaborative studies for real-time PCR-based quantitation methods for genetically modified crops.

    PubMed

    Watanabe, Satoshi; Sawada, Hiroshi; Naito, Shigehiro; Akiyama, Hiroshi; Teshima, Reiko; Furui, Satoshi; Kitta, Kazumi; Hino, Akihiro

    2013-01-01

    To study impacts of various random effects and parameters of collaborative studies on the precision of quantitation methods of genetically modified (GM) crops, we developed a set of random effects models for cycle time values of a standard curve-based relative real-time PCR that makes use of an endogenous gene sequence as the internal standard. The models and data from a published collaborative study for six GM lines at four concentration levels were used to simulate collaborative studies under various conditions. Results suggested that by reducing the numbers of well replications from three to two, and standard levels of endogenous sequence from five to three, the number of unknown samples analyzable on a 96-well PCR plate in routine analyses could be almost doubled, and still the acceptable repeatability RSD (RSDr < or = 25%) and the reproducibility RSD (RSDR < 35%) of the collaborative study could be met. Further, RSDr and RSD(R) were found most sensitive to random effects attributable to inhomogeneity among blind replicates, but they were little influenced by those attributable to DNA extractions. The proposed models are expected to be useful for optimizing standard curve-based relative quantitation methods for GM crops by real-time PCR and their collaborative studies.

  13. Current methods for assessing safety of genetically modified crops as exemplified by data on Roundup Ready soybeans.

    PubMed

    Nair, Rashmi S; Fuchs, Roy L; Schuette, Sheila A

    2002-01-01

    Several laboratories have used recombinant DNA technology in plant breeding to improve compositional, processing, and agronomic characteristics of plants. These transformed plants have been extensively tested in field trials, have gained full regulatory approvals and are currently being marketed in a number of countries around the world. This paper briefly summarizes the approach used to assure the safety of foods and feeds derived from these genetically modified crops, as exemplified by data on Roundup Ready soybeans that has been developed by Monsanto Company using biotechnology in order to confer tolerance to glyphosate, the active ingredient in Roundup herbicide, by the production of the CP4 enolpyruvylshikimate-3-phosphate synthase protein. The results of the studies demonstrate that Roundup Ready soybeans are as safe as traditional soybeans with respect to food and feed safety.

  14. Genetic engineering in agriculture and corporate engineering in public debate: risk, public relations, and public debate over genetically modified crops.

    PubMed

    Patel, Rajeev; Torres, Robert J; Rosset, Peter

    2005-01-01

    Corporations have long influenced environmental and occupational health in agriculture, doing a great deal of damage, making substantial profits, and shaping public debate to make it appear that environmental misfortunes are accidents of an otherwise well-functioning system, rather than systemic. The debate over the genetically modified (GM) crops is an example. The largest producer of commercial GM seeds, Monsanto, exemplifies the industry's strategies: the invocation of poor people as beneficiaries, characterization of opposition as technophobic or anti-progress, and portrayal of their products as environmentally beneficial in the absence of or despite the evidence. This strategy is endemic to contemporary market capitalism, with its incentives to companies to externalize health and environmental costs to increase profits.

  15. Molecular effects of resistance elicitors from biological origin and their potential for crop protection

    PubMed Central

    Wiesel, Lea; Newton, Adrian C.; Elliott, Ian; Booty, David; Gilroy, Eleanor M.; Birch, Paul R. J.; Hein, Ingo

    2014-01-01

    Plants contain a sophisticated innate immune network to prevent pathogenic microbes from gaining access to nutrients and from colonizing internal structures. The first layer of inducible response is governed by the plant following the perception of microbe- or modified plant-derived molecules. As the perception of these molecules results in a plant response that can provide efficient resistance toward non-adapted pathogens they can also be described as “defense elicitors.” In compatible plant/microbe interactions, adapted microorganisms have means to avoid or disable this resistance response and promote virulence. However, this requires a detailed spatial and temporal response from the invading pathogens. In agricultural practice, treating plants with isolated defense elicitors in the absence of pathogens can promote plant resistance by uncoupling defense activation from the effects of pathogen virulence determinants. The plant responses to plant, bacterial, oomycete, or fungal-derived elicitors are not, in all cases, universal and need elucidating prior to the application in agriculture. This review provides an overview of currently known elicitors of biological rather than synthetic origin and places their activity into a molecular context. PMID:25484886

  16. Hierarchical metabolomics demonstrates substantial compositional similarity between genetically modified and conventional potato crops

    PubMed Central

    Catchpole, Gareth S.; Beckmann, Manfred; Enot, David P.; Mondhe, Madhav; Zywicki, Britta; Taylor, Janet; Hardy, Nigel; Smith, Aileen; King, Ross D.; Kell, Douglas B.; Fiehn, Oliver; Draper, John

    2005-01-01

    There is current debate whether genetically modified (GM) plants might contain unexpected, potentially undesirable changes in overall metabolite composition. However, appropriate analytical technology and acceptable metrics of compositional similarity require development. We describe a comprehensive comparison of total metabolites in field-grown GM and conventional potato tubers using a hierarchical approach initiating with rapid metabolome “fingerprinting” to guide more detailed profiling of metabolites where significant differences are suspected. Central to this strategy are data analysis procedures able to generate validated, reproducible metrics of comparison from complex metabolome data. We show that, apart from targeted changes, these GM potatoes in this study appear substantially equivalent to traditional cultivars. PMID:16186495

  17. Hierarchical metabolomics demonstrates substantial compositional similarity between genetically modified and conventional potato crops.

    PubMed

    Catchpole, Gareth S; Beckmann, Manfred; Enot, David P; Mondhe, Madhav; Zywicki, Britta; Taylor, Janet; Hardy, Nigel; Smith, Aileen; King, Ross D; Kell, Douglas B; Fiehn, Oliver; Draper, John

    2005-10-04

    There is current debate whether genetically modified (GM) plants might contain unexpected, potentially undesirable changes in overall metabolite composition. However, appropriate analytical technology and acceptable metrics of compositional similarity require development. We describe a comprehensive comparison of total metabolites in field-grown GM and conventional potato tubers using a hierarchical approach initiating with rapid metabolome "fingerprinting" to guide more detailed profiling of metabolites where significant differences are suspected. Central to this strategy are data analysis procedures able to generate validated, reproducible metrics of comparison from complex metabolome data. We show that, apart from targeted changes, these GM potatoes in this study appear substantially equivalent to traditional cultivars.

  18. Loop-mediated isothermal amplification: rapid visual and real-time methods for detection of genetically modified crops.

    PubMed

    Randhawa, Gurinder Jit; Singh, Monika; Morisset, Dany; Sood, Payal; Zel, Jana

    2013-11-27

    A rapid, reliable, and sensitive loop-mediated isothermal amplification (LAMP) system was developed for screening of genetically modified organisms (GMOs). The optimized LAMP assays using designed primers target commonly employed promoters, i.e., Cauliflower Mosaic Virus 35S (P-35S) and Figwort Mosaic Virus promoter (P-FMV), and marker genes, i.e., aminoglycoside 3'-adenyltransferase (aadA), neomycin phosphotransferase II (nptII), and β-glucuronidase (uidA). The specificity and performance of the end-point and real-time LAMP assays were confirmed using eight genetically modified (GM) cotton events on four detection systems, employing two chemistries. LAMP assays on the isothermal real-time system were found to be most sensitive, detecting up to four target copies, within 35 min. The LAMP assays herein presented using alternate detection systems can be effectively utilized for rapid and cost-effective screening of the GM status of a sample, irrespective of the crop species or GM trait. These assays coupled with a fast and simple DNA extraction method may further facilitate on-site GMO screening.

  19. Modified developer increases line resolution in photosensitive resist

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Standard developer solution is mixed with dipropyl carbonate. This reduces swelling in the photosensitive resist and permits application of relatively thick films with minimal pinhole formation and increased line resolution.

  20. Arabidopsis dual resistance proteins, both RPS4 and RRS1, are required for resistance to bacterial wilt in transgenic Brassica crops.

    PubMed

    Narusaka, Mari; Hatakeyama, Katsunori; Shirasu, Ken; Narusaka, Yoshihiro

    2014-01-01

    Bacterial wilt phytopathogen Ralstonia solanacearum is a serious soil-borne disease that attacks several economically important plants worldwide, including Brassicaceae. Previous studies indicate that recognition of avirulence (Avr)-effector PopP2 by resistance (R) protein, RRS1-R, and physical interaction between RRS1-R and PopP2 in the nucleus are required for resistance. Of late, we showed that a pair of Arabidopsis thaliana TIR-NLR proteins, RRS1 and RPS4, function together in disease resistance against multiple pathogen isolates. Here, we report that dual R proteins, RRS1 and RPS4, from A. thaliana ecotype Wassilewskija confer resistance to bacterial wilt in transgenic Brassica crops. For practical applications, this finding may provide a new strategy for developing disease resistant plants that express R genes from other plants.

  1. Adaptation of the ToxRTool to Assess the Reliability of Toxicology Studies Conducted with Genetically Modified Crops and Implications for Future Safety Testing.

    PubMed

    Koch, Michael S; DeSesso, John M; Williams, Amy Lavin; Michalek, Suzanne; Hammond, Bruce

    2016-01-01

    To determine the reliability of food safety studies carried out in rodents with genetically modified (GM) crops, a Food Safety Study Reliability Tool (FSSRTool) was adapted from the European Centre for the Validation of Alternative Methods' (ECVAM) ToxRTool. Reliability was defined as the inherent quality of the study with regard to use of standardized testing methodology, full documentation of experimental procedures and results, and the plausibility of the findings. Codex guidelines for GM crop safety evaluations indicate toxicology studies are not needed when comparability of the GM crop to its conventional counterpart has been demonstrated. This guidance notwithstanding, animal feeding studies have routinely been conducted with GM crops, but their conclusions on safety are not always consistent. To accurately evaluate potential risks from GM crops, risk assessors need clearly interpretable results from reliable studies. The development of the FSSRTool, which provides the user with a means of assessing the reliability of a toxicology study to inform risk assessment, is discussed. Its application to the body of literature on GM crop food safety studies demonstrates that reliable studies report no toxicologically relevant differences between rodents fed GM crops or their non-GM comparators.

  2. Safety evaluation of genetically modified mustard (V4) seeds in terms of allergenicity: comparison with native crop.

    PubMed

    Misra, Amita; Kumar, Sandeep; Verma, Alok Kumar; Chanana, Nidhi P; Das, Mukul; Dhawan, Vibha; Dwivedi, Premendra D

    2012-01-01

    Genetically modified (GM) mustard line (V4) with increased carotenoid content was compared with native mustard to find the difference in allergenic potential, if any. Simulated gastric fluid (SGF) digestibility of crude protein extract from GM as well as its native counterpart mustard crop was envisaged to understand the intended or unintended changes in GM crop along with IgE immunoblotting. BALB/c mice were used as model for allergenicity studies for monitoring total and specific IgE, specific IgG1, histamine level, histopathology, and systemic anaphylaxis score. Allergenicity of mustard was checked in humans by clinical history, skin prick test and IgE levels. Similar results were evident by significant increase in total IgE, specific IgE, IgG1, histamine levels, in GM and native mustard in comparison to control group. Prominent anaphylactic symptoms (score 2: 60%; score 3: 20%; score 4: 20% in native mustard and score 2: 40%; score 3: 40%; score 4: 20% in GM mustard) and eruptive histopathological changes were observed in both GM and native mustard when compared with controls. One protein of approximately 16 kDa was found stable up to 1 h in both GM as well as non GM mustard. IgE immunoblotting detected three protein components of approximately 29, 24 and 16 kDa in both GM and non GM varieties. Collectively, our data demonstrate substantially equivalent allergic responses against GM as well as its native counterpart. Therefore, the GM mustard may be as safe as its native counterpart with reference to allergenic responses.

  3. Modified cellulose synthase gene from 'Arabidopsis thaliana' confers herbicide resistance to plants

    SciTech Connect

    Somerville, Chris R.; Scieble, Wolf

    2000-10-11

    Cellulose synthase ('CS'), a key enzyme in the biosynthesis of cellulose in plants is inhibited by herbicides comprising thiazolidinones such as 5-tert-butyl-carbamoyloxy-3-(3-trifluromethyl) phenyl-4-thiazolidinone (TZ), isoxaben and 2,6-dichlorobenzonitrile (DCB). Two mutant genes encoding isoxaben and TZ-resistant cellulose synthase have been isolated from isoxaben and TZ-resistant Arabidopsis thaliana mutants. When compared with the gene coding for isoxaben or TZ-sensitive cellulose synthase, one of the resistant CS genes contains a point mutation, wherein glycine residue 998 is replaced by an aspartic acid. The other resistant mutation is due to a threonine to isoleucine change at amino acid residue 942. The mutant CS gene can be used to impart herbicide resistance to a plant; thereby permitting the utilization of the herbicide as a single application at a concentration which ensures the complete or substantially complete killing of weeds, while leaving the transgenic crop plant essentially undamaged.

  4. Modified cellulose synthase gene from Arabidopsis thaliana confers herbicide resistance to plants

    DOEpatents

    Somerville, Chris R.; Scheible, Wolf

    2007-07-10

    Cellulose synthase ("CS"), a key enzyme in the biosynthesis of cellulose in plants is inhibited by herbicides comprising thiazolidinones such as 5-tert-butyl-carbamoyloxy-3-(3-trifluromethyl)phenyl-4-thiazolidinone (TZ), isoxaben and 2,6-dichlorobenzonitrile (DCB). Two mutant genes encoding isoxaben and TZ-resistant cellulose synthase have been isolated from isoxaben and TZ-resistant Arabidopsis thaliana mutants. When compared with the gene coding for isoxaben or TZ-sensitive cellulose synthase, one of the resistant CS genes contains a point mutation, wherein glycine residue 998 is replaced by an aspartic acid. The other resistant mutation is due to a threonine to isoleucine change at amino acid residue 942. The mutant CS gene can be used to impart herbicide resistance to a plant; thereby permitting the utilization of the herbicide as a single application at a concentration which ensures the complete or substantially complete killing of weeds, while leaving the transgenic crop plant essentially undamaged.

  5. Novel heat-resistance UV curable waterborne polyurethane coatings modified by melamine

    NASA Astrophysics Data System (ADS)

    Fang, Z. H.; Duan, H. Y.; Zhang, Z. H.; Wang, J.; Li, D. Q.; Huang, Y. X.; Shang, J. J.; Liu, Z. Y.

    2011-03-01

    Novel UV curable waterborne polyurethane coatings (UVWPU) modified by melamine was prepared using isophorone diisocyanate (IPDI), polyethylene glycol (PEG), α,α-dimethylol propionic acid (DMPA), hydroxyethyl acrylate (HEA) as main materials. Copolymer structure was verified using Fourier transform infrared spectroscopy (FT-IR). Performance of the coatings was evaluated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), and mechanical tests such as pencil hardness and resistance to water. The results showed that the modified UVWPU film had the good thermal resistance, water resistance and mechanical properties. The optimum melamine dosage was 4.70 wt.%, the glass transition temperature ( Tg) of the modified film increased by 20.4 °C and 5% weight-loss temperature (253 °C) increased by 105 °C. No change color, crinkle, desquamate, dehisce and frothy were found after the modified film dried at 130 °C for 2 h.

  6. Interaction between various resistance modifiers and apoptosis inducer 12H-benzo[alpha]phenothiazine.

    PubMed

    Mucsi, Ilona; Varga, Andreas; Kawase, Masami; Motohashi, Noboru; Molnar, Joseph

    2002-01-01

    The effect of some resistance modifiers on apoptosis induction by a benzo[alpha]phenothiazine derivative was studied on the L5178Y mouse lymphoma cells (parent) and its multidrug resistant (MDR) subline. For evaluation of apoptosis the cells were stained with FITC-labelled annexin V and propidium iodide and the results were analysed by flow cytometry. 12H-benzo[alpha]phenothiazine [M627] induced apoptosis both in the parent cells and in the MDR cells. The apoptosis induction by [M627] was not affected significantly by post- or pre-treatment with resistance modifiers, while in the cells treated by (+/-)-verapamil before and after apoptosis induction with [M627], the apoptosis was somewhat higher. The resistance modifier compounds alone also induced apoptosis and it was slightly higher in the parent cells than its MDR1/A gene-transformed subline.

  7. Successful technologies and approaches used to develop and manage resistance against crop diseases and pests

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Food security is highly dependent on many factors including biological, climate related, and political. Soon after Mendel showed that phenotypic traits could be inherited through hybridization, scientists have been using classical genetics to increase crop production. Part of the increase in crop pr...

  8. UV resistance and dimensional stability of wood modified with isopropenyl acetate.

    PubMed

    Nagarajappa, Giridhar B; Pandey, Krishna K

    2016-02-01

    Chemical modification of Rubberwood (Hevea brasiliensis Müll.Arg) with isopropenyl acetate (IPA) in the presence of anhydrous aluminum chloride as a catalyst has been carried out under solvent free conditions. The level of modification was estimated by determining the weight percent gain and modified wood was characterized by FTIR-ATR and CP/MAS (13)C NMR spectroscopy. The effect of catalyst concentration on WPG was studied. UV resistance, moisture adsorption and dimensional stability of modified wood were evaluated. UV resistance of modified wood was evaluated by exposing unmodified and modified wood to UV irradiation in a QUV accelerated weathering tester. Unmodified wood showed rapid color changes and degradation of lignin upon exposure to UV light. Chemical modification of wood polymers with IPA was effective in reducing light induced color changes (photo-yellowing) at wood surfaces. In contrast to unmodified wood, modified wood exhibited bleaching. FTIR analysis of modified wood exposed to UV light indicated stabilization of wood polymers against UV degradation. Modified wood showed good dimensional stability and hydrophobicity. Thermogravimetric analysis showed that modification with IPA improved thermal stability of wood. Improved dimensional stability and UV resistance of modified wood indicates IPA as a promising reagent since there is no acid byproduct of reaction as observed in case of other esterification reactions.

  9. Construction of a reference plasmid molecule containing eight targets for the detection of genetically modified crops.

    PubMed

    Wang, Xiumin; Teng, Da; Yang, Yalin; Tian, Fang; Guan, Qingfeng; Wang, Jianhua

    2011-04-01

    A standard plasmid containing eight targets was developed for quantitative detection of genetically modified (GM) soybeans and cotton. These eight targets were joined in tandem to form the pTLE8 plasmid with a length of 3,680 bp. This plasmid contains part of the endogenous soybean Lec1 gene, the Cauliflower mosaic virus (CaMV) 35S promoter, the Agrobacterium tumefaciens nopaline synthase (NOS) terminator, the PAT gene of the soybean line A2704-12, the event-specific 5'-junction region of Roundup-Ready Soya (RRS, 35SG), the Cry1A(c) gene from Bacillus thuringiensis (Bt), the endogenous cotton Sad1 gene, and a part of RRS EPSPS gene. The PCR efficiencies with pTLE8 as a calibrator ranged from 99.4% to 100.2% for the standard curves of the RRS EPSPS gene and the taxon-specific Lec1 gene (R(2)≥0.996). The limits of detection and quantification were nine and 15 copies, respectively. The standard deviation (SD) and relative standard deviation (RSD) values of repeatability were from 0.09 to 0.52 and from 0.28% to 2.11%, and those for reproducibility were from 0.12 to 1.15 and 0.42% to 3.85%, respectively. The average conversion factor (Cf) for the CRMs RRS quantification was 0.91. The RSD of the mean values for known samples ranged from 3.09% to 18.53%, and the biases were from 0.5% to 40%. These results show that our method using the pTLE8 plasmid as a reference material (RM) is reliable and feasible in the identification of GM soybeans, thus paving the way for the establishment of identification management systems for various products containing GMO components.

  10. Quantifying the combined effects of climatic, crop and soil factors on surface resistance in a maize field

    NASA Astrophysics Data System (ADS)

    Li, Sien; Kang, Shaozhong; Zhang, Lu; Li, Fusheng; Hao, Xingmei; Ortega-Farias, Samuel; Guo, Weihua; Ji, Shasha; Wang, Jingtao; Jiang, Xuelian

    2013-05-01

    Land surface evapotranspiration (ET) is the central process in hydrological cycle. The accuracy in simulating ET is affected by the calculation of underlying surface resistance. However, the surface resistance is difficult to be measured and greatly affected by climatic, crop and soil factors. How to quantify the combined effects of these factors on surface resistance is still a challenge for hydrologists. Our study attempted to construct and validate a semi-empirical surface resistance model based on the analysis of the response pattern of surface resistance to climatic resistance, leaf area index (LAI) and soil moisture. The surface resistance was derived by the re-arranged Penman-Monteith (PM) equation and the measured maize ET using eddy covariance in 2007. Results indicate that the ratio of surface resistance to climatic resistance showed a logarithmic relationship with LAI, and an exponential function as soil moisture when LAI was below 2. But the ratio was nearly constant and not sensitive to variation in LAI and soil moisture when LAI exceeded 2. Based on the relationships, a surface resistance model was further constructed and compared to the widely used Katerji-Perrier and Jarvis models over the sparse maize and grape canopy. Our resistance model combined with the PM equation improved the accuracy in estimating daily maize ET by 11% in 2007 and 4% in 2008, and vineyard ET by 7% against the Katerji-Perrier model combined with PM method, while by 32% in 2007 and 104% in 2008, and vineyard ET by 5% against the Jarvis model combined with PM method. Thus our model significantly improved the performance in simulating sparse vegetation ET and can be used to estimate daily surface resistance under the partial canopy condition.

  11. Sampling Strategies for Evaluating the Rate of Adventitious Transgene Presence in Non-Genetically Modified Crop Fields.

    PubMed

    Makowski, David; Bancal, Rémi; Bensadoun, Arnaud; Monod, Hervé; Messéan, Antoine

    2017-02-23

    According to E.U. regulations, the maximum allowable rate of adventitious transgene presence in non-genetically modified (GM) crops is 0.9%. We compared four sampling methods for the detection of transgenic material in agricultural non-GM maize fields: random sampling, stratified sampling, random sampling + ratio reweighting, random sampling + regression reweighting. Random sampling involves simply sampling maize grains from different locations selected at random from the field concerned. The stratified and reweighting sampling methods make use of an auxiliary variable corresponding to the output of a gene-flow model (a zero-inflated Poisson model) simulating cross-pollination as a function of wind speed, wind direction, and distance to the closest GM maize field. With the stratified sampling method, an auxiliary variable is used to define several strata with contrasting transgene presence rates, and grains are then sampled at random from each stratum. With the two methods involving reweighting, grains are first sampled at random from various locations within the field, and the observations are then reweighted according to the auxiliary variable. Data collected from three maize fields were used to compare the four sampling methods, and the results were used to determine the extent to which transgene presence rate estimation was improved by the use of stratified and reweighting sampling methods. We found that transgene rate estimates were more accurate and that substantially smaller samples could be used with sampling strategies based on an auxiliary variable derived from a gene-flow model.

  12. Benchmark study on glyphosate-resistant cropping systems in the United States. Part 1: Introduction to 2006-2008.

    PubMed

    Shaw, David R; Owen, Micheal D K; Dixon, Philip M; Weller, Stephen C; Young, Bryan G; Wilson, Robert G; Jordan, David L

    2011-07-01

    Glyphosate-resistant (GR) crop technology has dramatically impacted agriculture. The adoption of GR systems in canola, maize, cotton, soybean and sugar beets has been widespread in the United States. However, weed scientists are concerned that growers' current herbicide programs and weed management tactics will affect their sustainability and effectiveness. Without proper management, the potential for weed populations to express a high degree of resistance to glyphosate will adversely impact the utility of glyphosate. In 2005, weed scientists from six universities initiated a long-term research study to assess the sustainability of GR technology. This paper introduces five other articles in this series. Over 150 fields of at least 10 ha were selected to participate in a long-term field-scale study, and each field was split in half. On one-half the grower continued using the current weed management program; on the other half the grower used academic-recommended herbicide resistance best management practices. Field data were collected in 2006-2008 to determine the impact of the two weed management programs on weed populations, diversity, seedbank, crop yields and economic returns. This long-term study will provide invaluable data for determining the sustainability and profitability of diversified weed management programs designed to lower the risk of evolving weed resistance to glyphosate.

  13. Metamorphosis of cisgenic insect resistance research in the transgenic crop era

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The biotechnological revolution has forever changed agricultural research and crop production worldwide. Commercial agriculture now includes plants that produce enhanced yield and quality, survival in hostile environmental conditions, manufacture and express defensive toxins, and yield grains with ...

  14. Insulin resistance modifies the association between obesity and current asthma in adults.

    PubMed

    Cardet, Juan Carlos; Ash, Samuel; Kusa, Tope; Camargo, Carlos A; Israel, Elliot

    2016-08-01

    Insulin resistance potentiates the association between obesity and childhood asthma, but this relationship appears inconsistent in relatively small studies of adults. We investigated effect modification in adults using the National Health and Nutrition Examination Survey 2003-2012, a large, nationally representative database.Insulin resistance and a history of physician-diagnosed current asthma were obtained from 12 421 adults, ages 18-85 years. We used logistic regression to determine associations between obesity and current asthma, adjusting for age, sex, race/ethnicity, poverty income ratio and smoking status. An interaction term evaluated effect modification by insulin resistance of the obesity-asthma association.As expected, obesity was positively associated with current asthma. Insulin resistance modified this association, with obesity measured as body mass index, waist circumference or waist-to-height ratio. The relationship between obesity and current asthma was stronger with increasing insulin resistance tertiles (OR 2.05, 95% CI 2.76-3.00; p-value for interaction 0.03). This association was robust to adjustments for other components of the metabolic syndrome (hypertriglyceridaemia, hypertension, hyperglycaemia and systemic inflammation). None of these components were themselves effect modifiers of the obesity-asthma association.In this large, nationally representative sample, insulin resistance modified the association between obesity and current asthma in adults. Targeting insulin resistance may represent a novel therapeutic strategy for obese patients with asthma.

  15. Comparative environmental impact assessment of herbicides used on genetically modified and non-genetically modified herbicide-tolerant canola crops using two risk indicators.

    PubMed

    Oliver, Danielle P; Kookana, Rai S; Miller, Rosalind B; Correll, Raymond L

    2016-07-01

    Canola (Brassica napus L.) is the third largest field crop in Australia by area sown. Genetically modified (GM) and non-GM canola varieties released or being developed in Australia include Clearfield® (imidazolinone tolerant), TT (triazine tolerant), InVigor® (glufosinate-ammonium tolerant), Roundup Ready® - RR® (glyphosate tolerant) and Hyola® RT® (tolerant to both glyphosate and triazine). We used two risk assessment approaches - the Environmental Impact Quotient (EIQ) and the Pesticide Impact Rating Index (PIRI) - to compare the environmental risks associated with herbicides used in the canola varieties (GM and non-GM) that are currently grown or may be grown in the future. Risk assessments found that from an environmental impact viewpoint a number of herbicides used in the production of TT canola showed high relative risk in terms of mobility and ecotoxicity of herbicides. The EIQ field use rating values for atrazine and simazine in particular were high compared with those for glyphosate and trifluralin. Imazapic and imazapyr, which are only used in Clearfield® canola, had extremely low EIQ field use rating values, likely reflecting the very low application rates used for these chemicals (0.02 to 0.04kg/ha) compared with those used for atrazine and simazine (1.2 to 1.5kg/ha). The PIRI assessment showed that irrespective of the canola variety grown, trifluralin posed a high toxicity risk to fish (Rainbow trout, Oncorhynchus mykiss), algae and Daphnia sp. While the replacement of trifluralin with propyzamide had little effect on the mobility score, it greatly decreased the ecotoxicity score to fish, algae and Daphnia sp. due to the lower LC50 values for propyzamide compared with trifluralin. This study has shown that based on likelihood of off-site transport of herbicides in surface water and potential toxicity to non-target organisms, the GM canola varieties have no advantage over non-herbicide tolerant (non HT) or Clearfield® canola.

  16. Thermal fatigue resistance of cobalt-modified UDIMET 700

    NASA Technical Reports Server (NTRS)

    Bizon, P. T.

    1982-01-01

    The determination of comparative thermal fatigue resistances of five cobalt composition modifications of UDIMET 700 from fluidized bed tests is described. Cobalt compositional levels of 0.1, 4.3, 8.6, 12.8, 17.0 percent were being investigated in both the bare and coated (NiCrAlY overlay) conditions. Triplicate tests of each variation including duplicate tests of three control alloys are under investigation. Fluidized beds were maintained at 550 and 1850 F for the first 5500 cycles at which time the hot bed was increased to 1922 F. Immersion time in each bed is always 3 minutes. Upon the completion of 10,000 cycles, it appears that the 8.6 percent cobalt level gives the best thermal fatigue life. Considerable deformation of the test bars was observed.

  17. Strategies to overcome the action of aminoglycoside-modifying enzymes for treating resistant bacterial infections

    PubMed Central

    Labby, Kristin J; Garneau-Tsodikova, Sylvie

    2013-01-01

    Shortly after the discovery of the first antibiotics, bacterial resistance began to emerge. Many mechanisms give rise to resistance; the most prevalent mechanism of resistance to the aminoglycoside (AG) family of antibiotics is the action of aminoglycoside-modifying enzymes (AMEs). Since the identification of these modifying enzymes, many efforts have been put forth to prevent their damaging alterations of AGs. These diverse strategies are discussed within this review, including: creating new AGs that are unaffected by AMEs; developing inhibitors of AMEs to be co-delivered with AGs; or regulating AME expression. Modern high-throughput methods as well as drug combinations and repurposing are highlighted as recent drug-discovery efforts towards fighting the increasing antibiotic resistance crisis. PMID:23859208

  18. Overexpression of a Modified Plant Thionin Enhances Disease Resistance to Citrus Canker and Huanglongbing (HLB).

    PubMed

    Hao, Guixia; Stover, Ed; Gupta, Goutam

    2016-01-01

    Huanglongbing (HLB or citrus greening disease) caused by Candidatus Liberibacter asiaticus (Las) is a great threat to the US citrus industry. There are no proven strategies to eliminate HLB disease and no cultivar has been identified with strong HLB resistance. Citrus canker is also an economically important disease associated with a bacterial pathogen (Xanthomonas citri). In this study, we characterized endogenous citrus thionins and investigated their expression in different citrus tissues. Since no HLB-resistant citrus cultivars have been identified, we attempted to develop citrus resistant to both HLB and citrus canker through overexpression of a modified plant thionin. To improve effectiveness for disease resistance, we modified and synthesized the sequence encoding a plant thionin and cloned into the binary vector pBinPlus/ARS. The construct was then introduced into Agrobacterium strain EHA105 for citrus transformation. Transgenic Carrizo plants expressing the modified plant thionin were generated by Agrobacterium-mediated transformation. Successful transformation and transgene gene expression was confirmed by molecular analysis. Transgenic Carrizo plants expressing the modified thionin gene were challenged with X. citri 3213 at a range of concentrations, and a significant reduction in canker symptoms and a decrease in bacterial growth were demonstrated compared to nontransgenic plants. Furthermore, the transgenic citrus plants were challenged with HLB via graft inoculation. Our results showed significant Las titer reduction in roots of transgenic Carrizo compared with control plants and reduced scion Las titer 12 months after graft inoculation. These data provide promise for engineering citrus disease resistance against HLB and canker.

  19. Ex-Ante Economic Impact Assessment of Genetically Modified Banana Resistant to Xanthomonas Wilt in the Great Lakes Region of Africa

    PubMed Central

    Ainembabazi, John Herbert; Tripathi, Leena; Rusike, Joseph; Abdoulaye, Tahirou; Manyong, Victor

    2015-01-01

    Background Credible empirical evidence is scanty on the social implications of genetically modified (GM) crops in Africa, especially on vegetatively propagated crops. Little is known about the future success of introducing GM technologies into staple crops such as bananas, which are widely produced and consumed in the Great Lakes Region of Africa (GLA). GM banana has a potential to control the destructive banana Xanthomonas wilt disease. Objective To gain a better understanding of future adoption and consumption of GM banana in the GLA countries which are yet to permit the production of GM crops; specifically, to evaluate the potential economic impacts of GM cultivars resistant to banana Xanthomonas wilt disease. Data Sources The paper uses data collected from farmers, traders, agricultural extension agents and key informants in the GLA. Analysis We analyze the perceptions of the respondents about the adoption and consumption of GM crop. Economic surplus model is used to determine future economic benefits and costs of producing GM banana. Results On the release of GM banana for commercialization, the expected initial adoption rate ranges from 21 to 70%, while the ceiling adoption rate is up to 100%. Investment in the development of GM banana is economically viable. However, aggregate benefits vary substantially across the target countries ranging from US$ 20 million to 953 million, highest in countries where disease incidence and production losses are high, ranging from 51 to 83% of production. Conclusion The findings support investment in the development of GM banana resistant to Xanthomonas wilt disease. The main beneficiaries of this technology development are farmers and consumers, although the latter benefit more than the former from reduced prices. Designing a participatory breeding program involving farmers and consumers signifies the successful adoption and consumption of GM banana in the target countries. PMID:26414379

  20. Surprising Alteration of Antibacterial Activity of 5″-Modified Neomycin against Resistant Bacteria

    PubMed Central

    Zhang, Jianjun; Chiang, Fang-I; Wu, Long; Czyryca, Przemyslaw Greg; Li, Ding; Chang, Cheng-Wei Tom

    2009-01-01

    A facile synthetic protocol for the production of neomycin B derivatives with various modifications at the 5″ position has been developed. Structural activity relationship (SAR) against aminoglycoside resistant bacteria equipped with various aminoglycoside-modifying enzymes (AME's) was investigated. Enzymatic and molecular modeling studies reveal that the superb substrate promiscuity of AME's allows the resistant bacteria to cope with diverse structural modifications despite the observation that several derivatives show enhanced antibacterial activity than the parent neomycin. Surprisingly, when testing synthetic neomycin derivatives against other human pathogens, two leads exhibit prominent activity against both Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) that are known to exert high level of resistance against clinically used aminoglycosides. These findings can be extremely useful in developing new aminoglycoside antibiotics against resistant bacteria. Our result also suggests that new biological and antimicrobial activities can be obtained by chemical modifications of old drugs. PMID:19012394

  1. Effect of Chromium Addition to the Low Temperature Hot Corrosion Resistance of Platinum Modified Aluminide Coatings.

    DTIC Science & Technology

    1985-12-01

    Diffusion aluminide coatings were the first coatings developed for hot corrosion resistance. Aluminum is applied to the surface of the superalloy by a...D.H., "Mechanisms of Formation of Diffusion Aluminide Coatings on Nickel-oase Superalloys , Oxidation of Metals, v. 3, pp. 475-477, 1971. 17. Lehnert...Classification) E.FFECT OF CHROMIUJM ADDITION TO THE LOW TEMPERATURE HOT CORROSION RESISTANCE OF PLATINUM MODIFIED ALUMINIDE COATINGS 2 PERSONAL AUTHOR(S) Dust

  2. Allelic Variation on Murine Chromosome 11 Modifies Host Inflammatory Responses and Resistance to Bacillus anthracis

    DTIC Science & Technology

    2011-12-01

    Allelic Variation on Murine Chromosome 11 Modifies Host Inflammatory Responses and Resistance to Bacillus anthracis Jill K. Terra1, Bryan France1...of America Abstract Anthrax is a potentially fatal disease resulting from infection with Bacillus anthracis. The outcome of infection is influenced by...Inflammatory Responses and Resistance to Bacillus anthracis. PLoS Pathog 7(12): e1002469. doi:10.1371/journal.ppat.1002469 Editor: Theresa M. Koehler, The

  3. The overexpression of an Amaranthus hypochondriacus NF-YC gene modifies growth and confers water deficit stress resistance in Arabidopsis.

    PubMed

    Palmeros-Suárez, Paola A; Massange-Sánchez, Julio A; Martínez-Gallardo, Norma A; Montero-Vargas, Josaphat M; Gómez-Leyva, Juan F; Délano-Frier, John P

    2015-11-01

    Nuclear factor-Y (NF-Y), is a plant heterotrimeric transcription factor constituted by NF-YA, NF-YB and NF-YC subunits. The function of many NF-Y subunits, mostly of the A and B type, has been studied in plants, but knowledge regarding the C subunit remains fragmentary. Here, a water stress-induced NF-YC gene from Amaranthus hypochondriacus (AhNF-YC) was further characterized by its overexpression in transgenic Arabidospis thaliana plants. A role in development was inferred from modified growth rates in root, rosettes and inflorescences recorded in AhNF-YC overexpressing Arabidopsis plants, in addition to a delayed onset of flowering. Also, the overexpression of AhNF-YC caused increased seedling sensitivity to abscisic acid (ABA), and influenced the expression of several genes involved in secondary metabolism, development and ABA-related responses. An altered expression of the latter in water stressed and recovered transgenic plants, together with the observed increase in ABA sensitivity, suggested that their increased water stress resistance was partly ABA-dependent. An untargeted metabolomic analysis also revealed an altered metabolite pattern, both in normal and water stress/recovery conditions. These results suggest that AhNF-YC may play an important regulatory role in both development and stress, and represents a candidate gene for the engineering of abiotic stress resistance in commercial crops.

  4. Defining terms for proactive management of resistance to Bt crops and pesticides.

    PubMed

    Tabashnik, Bruce E; Mota-Sanchez, David; Whalon, Mark E; Hollingworth, Robert M; Carrière, Yves

    2014-04-01

    Evolution of pest resistance to pesticides is an urgent global problem with resistance recorded in at least 954 species of pests, including 546 arthropods, 218 weeds, and 190 plant pathogens. To facilitate understanding and management of resistance, we provide definitions of 50 key terms related to resistance. We confirm the broad, long-standing definition of resistance, which is a genetically based decrease in susceptibility to a pesticide, and the definition of "field-evolved resistance," which is a genetically based decrease in susceptibility to a pesticide in a population caused by exposure to the pesticide in the field. The impact of field-evolved resistance on pest control can vary from none to severe. We define "practical resistance" as field-evolved resistance that reduces pesticide efficacy and has practical consequences for pest control. Recognizing that resistance is not "all or none" and that intermediate levels of resistance can have a continuum of effects on pest control, we describe five categories of field-evolved resistance and use them to classify 13 cases of field-evolved resistance to five Bacillus thuringiensis (Bt) toxins in transgenic corn and cotton based on monitoring data from five continents for nine major pest species. We urge researchers to publish and analyze their resistance monitoring data in conjunction with data on management practices to accelerate progress in determining which actions will be most useful in response to specific data on the magnitude, distribution, and impact of resistance.

  5. Evidence for gene flow via seed dispersal from crop to wild relatives in Beta vulgaris (Chenopodiaceae): consequences for the release of genetically modified crop species with weedy lineages.

    PubMed Central

    Arnaud, J-F; Viard, F; Delescluse, M; Cuguen, J

    2003-01-01

    Gene flow and introgression from cultivated to wild plant populations have important evolutionary and ecological consequences and require detailed investigations for risk assessments of transgene escape into natural ecosystems. Sugar beets (Beta vulgaris ssp. vulgaris) are of particular concern because: (i) they are cross-compatible with their wild relatives (the sea beet, B. vulgaris ssp. maritima); (ii) crop-to-wild gene flow is likely to occur via weedy lineages resulting from hybridization events and locally infesting fields. Using a chloroplastic marker and a set of nuclear microsatellite loci, the occurrence of crop-to-wild gene flow was investigated in the French sugar beet production area within a 'contact-zone' in between coastal wild populations and sugar beet fields. The results did not reveal large pollen dispersal from weed to wild beets. However, several pieces of evidence clearly show an escape of weedy lineages from fields via seed flow. Since most studies involving the assessment of transgene escape from crops to wild outcrossing relatives generally focused only on pollen dispersal, this last result was unexpected: it points out the key role of a long-lived seed bank and highlights support for transgene escape via man-mediated long-distance dispersal events. PMID:12908976

  6. Invertebrate responses to the management of genetically modified herbicide-tolerant and conventional spring crops. II. Within-field epigeal and aerial arthropods.

    PubMed Central

    Haughton, A J; Champion, G T; Hawes, C; Heard, M S; Brooks, D R; Bohan, D A; Clark, S J; Dewar, A M; Firbank, L G; Osborne, J L; Perry, J N; Rothery, P; Roy, D B; Scott, R J; Woiwod, I P; Birchall, C; Skellern, M P; Walker, J H; Baker, P; Browne, E L; Dewar, A J G; Garner, B H; Haylock, L A; Horne, S L; Mason, N S; Sands, R J N; Walker, M J

    2003-01-01

    The effects of the management of genetically modified herbicide-tolerant (GMHT) crops on the abundances of aerial and epigeal arthropods were assessed in 66 beet, 68 maize and 67 spring oilseed rape sites as part of the Farm Scale Evaluations of GMHT crops. Most higher taxa were insensitive to differences between GMHT and conventional weed management, but significant effects were found on the abundance of at least one group within each taxon studied. Numbers of butterflies in beet and spring oilseed rape and of Heteroptera and bees in beet were smaller under the relevant GMHT crop management, whereas the abundance of Collembola was consistently greater in all GMHT crops. Generally, these effects were specific to each crop type, reflected the phenology and ecology of the arthropod taxa, were indirect and related to herbicide management. These results apply generally to agriculture across Britain, and could be used in mathematical models to predict the possible long-term effects of the widespread adoption of GMHT technology. The results for bees and butterflies relate to foraging preferences and might or might not translate into effects on population densities, depending on whether adoption leads to forage reductions over large areas. These species, and the detritivore Collembola, may be useful indicator species for future studies of GMHT management. PMID:14561319

  7. Invertebrate responses to the management of genetically modified herbicide-tolerant and conventional spring crops. II. Within-field epigeal and aerial arthropods.

    PubMed

    Haughton, A J; Champion, G T; Hawes, C; Heard, M S; Brooks, D R; Bohan, D A; Clark, S J; Dewar, A M; Firbank, L G; Osborne, J L; Perry, J N; Rothery, P; Roy, D B; Scott, R J; Woiwod, I P; Birchall, C; Skellern, M P; Walker, J H; Baker, P; Browne, E L; Dewar, A J G; Garner, B H; Haylock, L A; Horne, S L; Mason, N S; Sands, R J N; Walker, M J

    2003-11-29

    The effects of the management of genetically modified herbicide-tolerant (GMHT) crops on the abundances of aerial and epigeal arthropods were assessed in 66 beet, 68 maize and 67 spring oilseed rape sites as part of the Farm Scale Evaluations of GMHT crops. Most higher taxa were insensitive to differences between GMHT and conventional weed management, but significant effects were found on the abundance of at least one group within each taxon studied. Numbers of butterflies in beet and spring oilseed rape and of Heteroptera and bees in beet were smaller under the relevant GMHT crop management, whereas the abundance of Collembola was consistently greater in all GMHT crops. Generally, these effects were specific to each crop type, reflected the phenology and ecology of the arthropod taxa, were indirect and related to herbicide management. These results apply generally to agriculture across Britain, and could be used in mathematical models to predict the possible long-term effects of the widespread adoption of GMHT technology. The results for bees and butterflies relate to foraging preferences and might or might not translate into effects on population densities, depending on whether adoption leads to forage reductions over large areas. These species, and the detritivore Collembola, may be useful indicator species for future studies of GMHT management.

  8. The use of whole food animal studies in the safety assessment of genetically modified crops: limitations and recommendations.

    PubMed

    Bartholomaeus, Andrew; Parrott, Wayne; Bondy, Genevieve; Walker, Kate

    2013-11-01

    There is disagreement internationally across major regulatory jurisdictions on the relevance and utility of whole food (WF) toxicity studies on GM crops, with no harmonization of data or regulatory requirements. The scientific value, and therefore animal ethics, of WF studies on GM crops is a matter addressable from the wealth of data available on commercialized GM crops and WF studies on irradiated foods. We reviewed available GM crop WF studies and considered the extent to which they add to the information from agronomic and compositional analyses. No WF toxicity study was identified that convincingly demonstrated toxicological concern or that called into question the adequacy, sufficiency, and reliability of safety assessments based on crop molecular characterization, transgene source, agronomic characteristics, and/or compositional analysis of the GM crop and its near-isogenic line. Predictions of safety based on crop genetics and compositional analyses have provided complete concordance with the results of well-conducted animal testing. However, this concordance is primarily due to the improbability of de novo generation of toxic substances in crop plants using genetic engineering practices and due to the weakness of WF toxicity studies in general. Thus, based on the comparative robustness and reliability of compositional and agronomic considerations and on the absence of any scientific basis for a significant potential for de novo generation of toxicologically significant compositional alterations as a sole result of transgene insertion, the conclusion of this review is that WF animal toxicity studies are unnecessary and scientifically unjustifiable.

  9. The use of whole food animal studies in the safety assessment of genetically modified crops: Limitations and recommendations

    PubMed Central

    Bartholomaeus, Andrew; Parrott, Wayne; Bondy, Genevieve

    2013-01-01

    There is disagreement internationally across major regulatory jurisdictions on the relevance and utility of whole food (WF) toxicity studies on GM crops, with no harmonization of data or regulatory requirements. The scientific value, and therefore animal ethics, of WF studies on GM crops is a matter addressable from the wealth of data available on commercialized GM crops and WF studies on irradiated foods. We reviewed available GM crop WF studies and considered the extent to which they add to the information from agronomic and compositional analyses. No WF toxicity study was identified that convincingly demonstrated toxicological concern or that called into question the adequacy, sufficiency, and reliability of safety assessments based on crop molecular characterization, transgene source, agronomic characteristics, and/or compositional analysis of the GM crop and its near-isogenic line. Predictions of safety based on crop genetics and compositional analyses have provided complete concordance with the results of well-conducted animal testing. However, this concordance is primarily due to the improbability of de novo generation of toxic substances in crop plants using genetic engineering practices and due to the weakness of WF toxicity studies in general. Thus, based on the comparative robustness and reliability of compositional and agronomic considerations and on the absence of any scientific basis for a significant potential for de novo generation of toxicologically significant compositional alterations as a sole result of transgene insertion, the conclusion of this review is that WF animal toxicity studies are unnecessary and scientifically unjustifiable. PMID:24164514

  10. Effects of biotechnology on biodiversity: herbicide-tolerant and insect-resistant GM crops.

    PubMed

    Ammann, Klaus

    2005-08-01

    Biodiversity is threatened by agriculture as a whole, and particularly also by traditional methods of agriculture. Knowledge-based agriculture, including GM crops, can reduce this threat in the future. The introduction of no-tillage practices, which are beneficial for soil fertility, has been encouraged by the rapid spread of herbicide-tolerant soybeans in the USA. The replacement of pesticides through Bt crops is advantageous for the non-target insect fauna in test-fields. The results of the British Farm Scale experiment are discussed. Biodiversity differences can mainly be referred to as differences in herbicide application management.

  11. An individual-based model of the evolution of pesticide resistance in heterogeneous environments: control of Meligethes aeneus population in oilseed rape crops.

    PubMed

    Stratonovitch, Pierre; Elias, Jan; Denholm, Ian; Slater, Russell; Semenov, Mikhail A

    2014-01-01

    Preventing a pest population from damaging an agricultural crop and, at the same time, preventing the development of pesticide resistance is a major challenge in crop protection. Understanding how farming practices and environmental factors interact with pest characteristics to influence the spread of resistance is a difficult and complex task. It is extremely challenging to investigate such interactions experimentally at realistic spatial and temporal scales. Mathematical modelling and computer simulation have, therefore, been used to analyse resistance evolution and to evaluate potential resistance management tactics. Of the many modelling approaches available, individual-based modelling of a pest population offers most flexibility to include and analyse numerous factors and their interactions. Here, a pollen beetle (Meligethes aeneus) population was modelled as an aggregate of individual insects inhabiting a spatially heterogeneous landscape. The development of the pest and host crop (oilseed rape) was driven by climatic variables. The agricultural land of the landscape was managed by farmers applying a specific rotation and crop protection strategy. The evolution of a single resistance allele to the pyrethroid lambda cyhalothrin was analysed for different combinations of crop management practices and for a recessive, intermediate and dominant resistance allele. While the spread of a recessive resistance allele was severely constrained, intermediate or dominant resistance alleles showed a similar response to the management regime imposed. Calendar treatments applied irrespective of pest density accelerated the development of resistance compared to ones applied in response to prescribed pest density thresholds. A greater proportion of spring-sown oilseed rape was also found to increase the speed of resistance as it increased the period of insecticide exposure. Our study demonstrates the flexibility and power of an individual-based model to simulate how farming

  12. An Individual-Based Model of the Evolution of Pesticide Resistance in Heterogeneous Environments: Control of Meligethes aeneus Population in Oilseed Rape Crops

    PubMed Central

    Stratonovitch, Pierre; Elias, Jan; Denholm, Ian; Slater, Russell; Semenov, Mikhail A.

    2014-01-01

    Preventing a pest population from damaging an agricultural crop and, at the same time, preventing the development of pesticide resistance is a major challenge in crop protection. Understanding how farming practices and environmental factors interact with pest characteristics to influence the spread of resistance is a difficult and complex task. It is extremely challenging to investigate such interactions experimentally at realistic spatial and temporal scales. Mathematical modelling and computer simulation have, therefore, been used to analyse resistance evolution and to evaluate potential resistance management tactics. Of the many modelling approaches available, individual-based modelling of a pest population offers most flexibility to include and analyse numerous factors and their interactions. Here, a pollen beetle (Meligethes aeneus) population was modelled as an aggregate of individual insects inhabiting a spatially heterogeneous landscape. The development of the pest and host crop (oilseed rape) was driven by climatic variables. The agricultural land of the landscape was managed by farmers applying a specific rotation and crop protection strategy. The evolution of a single resistance allele to the pyrethroid lambda cyhalothrin was analysed for different combinations of crop management practices and for a recessive, intermediate and dominant resistance allele. While the spread of a recessive resistance allele was severely constrained, intermediate or dominant resistance alleles showed a similar response to the management regime imposed. Calendar treatments applied irrespective of pest density accelerated the development of resistance compared to ones applied in response to prescribed pest density thresholds. A greater proportion of spring-sown oilseed rape was also found to increase the speed of resistance as it increased the period of insecticide exposure. Our study demonstrates the flexibility and power of an individual-based model to simulate how farming

  13. Understanding mechanisms of host resistance against greenbug in cereal crops - an interdisciplinary, collaborative approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    At Texas AgriLife Research - Amarillo, we have an ongoing research program focusing on elucidating the mechanisms of interactions between the phloem-feeding aphid pests and cereal crop hosts using the wheat-greenbug as a model system. During this workshop, recent results from our research on the fo...

  14. Effect of soil biochar amendment on grain crop resistance to Fusarium mycotoxin contamination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mycotoxin contamination of food and feed is among the top food safety concerns. Fusarium spp. cause serious diseases in cereal crops reducing yield and contaminating grain with mycotoxins that can be deleterious to human and animal health. Fusarium graminearum and Fusarium verticillioides infect whe...

  15. Assessment of insecticide resistance in five insect pests attacking field and vegetable crops in Nicaragua.

    PubMed

    Pérez, C J; Alvarado, P; Narváez, C; Miranda, F; Hernández, L; Vanegas, H; Hruska, A; Shelton, A M

    2000-12-01

    Field populations of Hypothenemus hampei (Ferrari), Plutella xylostella (L.), Spodoptera exigua (Hübner), Helicoverpa zea (Boddie) and Bemisia tabaci (Gennadius) were tested for resistance to several insecticides commonly used in Nicariagua. Assays were conducted to estimate the LD50s or LC50s and the corresponding resistance ratios. A diagnostic concentration was used to discriminate between susceptible and resistant strains of H. hampei. The tests with >6,000 H. hampei adults collected from six different sites indicate the absence of resistance to endosulfan. Resistance to cypermethrin, deltamethrin, chlorfluazuron, thiocyclam, and methamidophos was documented in six field populations of P. xylostella. High levels of resistance to cypermethrin and deltamethrin, but moderate levels of resistance to chlorpyriphos and methomyl, were also documented in two field populations of S. exigua. Moderate levels of resistance to cypermethrin, deltamethrin and chlorpyriphos were also documented in three field populations of H. zea. Moderate to high levels of resistance to bifenthrin, methamidophos and endosulfan were documented in four field populations of B. tabaci. The presence of significant correlations between LD50s or LC50s suggests the occurrence of cross-resistance or simultaneous selection for resistance by different insecticides with different modes of action. Our data could not differentiate between these two possibilities. Because insecticides will continue being used in Nicaragua, a resistance management program is urgently needed. The implementation of integrated pest management tactics must be accompanied by specific regulations for pesticide registration. In the future, pesticide registration regulations in Nicaragua should include periodic resistance monitoring. The mechanisms to cover the costs of resistance monitoring and resistance management should also be established.

  16. Molecular genetics of aminoglycoside resistance genes and familial relationships of the aminoglycoside-modifying enzymes.

    PubMed Central

    Shaw, K J; Rather, P N; Hare, R S; Miller, G H

    1993-01-01

    The three classes of enzymes which inactivate aminoglycosides and lead to bacterial resistance are reviewed. DNA hybridization studies have shown that different genes can encode aminoglycoside-modifying enzymes with identical resistance profiles. Comparisons of the amino acid sequences of 49 aminoglycoside-modifying enzymes have revealed new insights into the evolution and relatedness of these proteins. A preliminary assessment of the amino acids which may be important in binding aminoglycosides was obtained from these data and from the results of mutational analysis of several of the genes encoding aminoglycoside-modifying enzymes. Recent studies have demonstrated that aminoglycoside resistance can emerge as a result of alterations in the regulation of normally quiescent cellular genes or as a result of acquiring genes which may have originated from aminoglycoside-producing organisms or from other resistant organisms. Dissemination of these genes is aided by a variety of genetic elements including integrons, transposons, and broad-host-range plasmids. As knowledge of the molecular structure of these enzymes increases, progress can be made in our understanding of how resistance to new aminoglycosides emerges. Images PMID:8385262

  17. Resistance evolution to the first generation of genetically modified Diabrotica-active Bt-maize events by western corn rootworm: management and monitoring considerations.

    PubMed

    Devos, Yann; Meihls, Lisa N; Kiss, József; Hibbard, Bruce E

    2013-04-01

    Western corn rootworm (Diabrotica virgifera virgifera; WCR) is a major coleopteran maize pest in North America and the EU, and has traditionally been managed through crop rotation and broad-spectrum soil insecticides. Genetically modified Bt-maize offers an additional management tool for WCR and has been valuable in reducing insecticide use and increasing farm income. A concern is that the widespread, repeated, and exclusive deployment of the same Bt-maize transformation event will result in the rapid evolution of resistance in WCR. This publication explores the potential of WCR to evolve resistance to plant-produced Bt-toxins from the first generation of Diabrotica-active Bt-maize events (MON 863 and MON 88017, DAS-59122-7 and MIR604), and whether currently implemented risk management strategies to delay and monitor resistance evolution are appropriate. In twelve of the twelve artificial selection experiments reported, resistant WCR populations were yielded rapidly. Field-selected resistance of WCR to Cry3Bb1 is documented in some US maize growing areas, where an increasing number of cases of unexpected damage of WCR larvae to Bt-maize MON 88017 has been reported. Currently implemented insect resistance management measures for Bt-crops usually rely on the high dose/refuge (HDR) strategy. Evidence (including laboratory, greenhouse and field data) indicates that several conditions contributing to the success of the HDR strategy may not be met for the first generation of Bt-maize events and WCR: (1) the Bt-toxins are expressed heterogeneously at a low-to-moderate dose in roots; (2) resistance alleles may be present at a higher frequency than initially assumed; (3) WCR may mate in a non-random manner; (4) resistance traits could have non-recessive inheritance; and (5) fitness costs may not necessarily be associated with resistance evolution. However, caution must be exercised when extrapolating laboratory and greenhouse results to field conditions. Model predictions

  18. Electrical resistivity of nanoporous gold modified with thiol self-assembled monolayers

    NASA Astrophysics Data System (ADS)

    Hakamada, Masataka; Kato, Naoki; Mabuchi, Mamoru

    2016-11-01

    The electrical resistivity of nanoporous gold (NPG) modified with thiol self-assembled monolayers (SAMs) has been measured at 298 K using a four-probe method. We found that the adsorption of thiol SAMs increases the electrical resistivity of NPG by up to 22.2%. Dependence of the electrical resistivity on the atmosphere (air or water) was also observed in SAMs-modified NPG, suggesting that the electronic states of the tail groups affect the electrons of the binding sulfur and adjacent surface gold atoms. The present results suggest that adsorption of thiol molecules can influence the behavior of the conducting electrons in NPG and that modification of NPG with SAMs may be useful for environmental sensing.

  19. A modified resistance equation for modeling underwater spark discharge with salinity and high pressure conditions

    SciTech Connect

    Zhao, Pengfei; Roy, Subrata

    2014-05-07

    This work investigates the performance of underwater spark discharge relating to bubble growth and decay under high pressure and with salinity conditions by introducing a modified form of the resistance equation. Here, we study salinity influence on circuit parameters by fitting the experimental data for which gap resistance is much larger in conductive water than in dielectric water. Accordingly, the resistance equation is modified by considering the influence of both plasma and its surrounding liquid. Thermal radiation effect of the bubble is also studied by comparing two different radiation models. Numerical results predict a larger bubble pressure for saline water but a reduced size and a smaller bubble cycle at a greater water depth. Such study may be useful in many saltwater applications, including that for deep sea conditions.

  20. Use of spectral imaging for insect resistance monitoring: EPA research on stewardship of Bt crops

    EPA Science Inventory

    A significant increase in genetically modified corn planting driven by biofuel demand is expected for future growing seasons. As demand increases, incidence of farmer non-compliance with mandated non-genetically modified refuge is likely to increase. As part of the FIFRA regist...

  1. Resistance Management Monitoring for the US Corn Crop to the Illinois Corn Growers Association

    EPA Science Inventory

    Significant increases in genetically modified corn planting are expected for future planted acreages approaching 80% of total corn plantings anticipated by 2009. As demand increases, incidence of farmer non-compliance with mandated non-genetically modified refuge is likely to in...

  2. Evaluation of antiseptics by the modified phenol coefficient method: sensitivity of methicillin-resistant Staphylococcus aureus.

    PubMed

    Sasatsu, M; Shimizu, K; Noguchi, N; Kono, M

    1994-01-01

    The relationship between an effective concentration and the duration of exposure to antiseptics was evaluated in strains of Staphylococcus aureus with a known genetic background, which include methicillin-resistant strains, using a modified version of the phenol coefficient method as part of an effort to investigate the antiseptic resistance of S. aureus. Chlorhexidine digluconate killed an antiseptic-sensitive strain within 1.5 min at 22 degrees C at a standard concentration (0.1%), whereas resistant strains still survived after 1.5 min. Povidone-iodine killed the sensitive strain within 1.5 min at a concentration of 0.1%, whereas it took this agent 3.0 and 4.5 min to kill low- and high-level resistant strains, respectively, at a concentration of 0.8%. These results indicate that the modified phenol coefficient method used is suitable for the evaluation of the sensitivity of microorganisms to antiseptics. An antiseptic-resistant chain that was associated with the ebr gene exhibited cross-resistance to povidone-iodine.

  3. Rutting and Fatigue Cracking Resistance of Waste Cooking Oil Modified Trinidad Asphaltic Materials

    PubMed Central

    Maharaj, Rean; Ramjattan-Harry, Vitra; Mohamed, Nazim

    2015-01-01

    The influence of waste cooking oil (WCO) on the performance characteristics of asphaltic materials indigenous to Trinidad, namely, Trinidad Lake Asphalt (TLA), Trinidad Petroleum Bitumen (TPB), and TLA : TPB (50 : 50) blend, was investigated to deduce the applicability of the WCO as a performance enhancer for the base asphalt. The rheological properties of complex modulus (G∗) and phase angle (δ) were measured for modified base asphalt blends containing up to 10% WCO. The results of rheology studies demonstrated that the incremental addition of WCO to the three parent binders resulted in incremental decreases in the rutting resistance (decrease in G∗/sinδ values) and increases in the fatigue cracking resistance (decrease in G∗sinδ value). The fatigue cracking resistance and rutting resistance for the TLA : TPB (50 : 50) blends were between those of the blends containing pure TLA and TPB. As operating temperature increased, an increase in the resistance to fatigue cracking and a decrease in the rutting resistance were observed for all of the WCO modified asphaltic blends. This study demonstrated the capability to create customized asphalt-WCO blends to suit special applications and highlights the potential for WCO to be used as an environmentally attractive option for improving the use of Trinidad asphaltic materials. PMID:26336652

  4. New Resistance Mechanism in Helicoverpa armigera Threatens Transgenic Crops Expressing Bacillus thuringiensis Cry1Ac Toxin

    PubMed Central

    Gunning, Robin V.; Dang, Ho T.; Kemp, Fred C.; Nicholson, Ian C.; Moores, Graham D.

    2005-01-01

    In Australia, the cotton bollworm, Helicoverpa armigera, has a long history of resistance to conventional insecticides. Transgenic cotton (expressing the Bacillus thuringiensis toxin Cry1Ac) has been grown for H. armigera control since 1996. It is demonstrated here that a population of Australian H. armigera has developed resistance to Cry1Ac toxin (275-fold). Some 70% of resistant H. armigera larvae were able to survive on Cry1Ac transgenic cotton (Ingard) The resistance phenotype is inherited as an autosomal semidominant trait. Resistance was associated with elevated esterase levels, which cosegregated with resistance. In vitro studies employing surface plasmon resonance technology and other biochemical techniques demonstrated that resistant strain esterase could bind to Cry1Ac protoxin and activated toxin. In vivo studies showed that Cry1Ac-resistant larvae fed Cy1Ac transgenic cotton or Cry1Ac-treated artificial diet had lower esterase activity than non-Cry1Ac-fed larvae. A resistance mechanism in which esterase sequesters Cry1Ac is proposed. PMID:15870346

  5. New resistance mechanism in Helicoverpa armigera threatens transgenic crops expressing Bacillus thuringiensis Cry1Ac toxin.

    PubMed

    Gunning, Robin V; Dang, Ho T; Kemp, Fred C; Nicholson, Ian C; Moores, Graham D

    2005-05-01

    In Australia, the cotton bollworm, Helicoverpa armigera, has a long history of resistance to conventional insecticides. Transgenic cotton (expressing the Bacillus thuringiensis toxin Cry1Ac) has been grown for H. armigera control since 1996. It is demonstrated here that a population of Australian H. armigera has developed resistance to Cry1Ac toxin (275-fold). Some 70% of resistant H. armigera larvae were able to survive on Cry1Ac transgenic cotton (Ingard) The resistance phenotype is inherited as an autosomal semidominant trait. Resistance was associated with elevated esterase levels, which cosegregated with resistance. In vitro studies employing surface plasmon resonance technology and other biochemical techniques demonstrated that resistant strain esterase could bind to Cry1Ac protoxin and activated toxin. In vivo studies showed that Cry1Ac-resistant larvae fed Cy1Ac transgenic cotton or Cry1Ac-treated artificial diet had lower esterase activity than non-Cry1Ac-fed larvae. A resistance mechanism in which esterase sequesters Cry1Ac is proposed.

  6. Spatial variation in soil penetration resistance according to the structural states of the soil and soybean crop yield

    NASA Astrophysics Data System (ADS)

    Wilson, Marcelo; Sasal, María Carolina; Oszust, José; Gabioud, Emmanuel; Melchiori, Ricardo

    2013-04-01

    The soil penetration resistance (PR) is used to identify and characterize soil layers densified by effects of tilling, and the results obtained are related to root growth and crop productivity. The aims of this work were: (i) to analyze the spatial variation in PR through resistance isolines in an Aquic Argiudoll with different long-term cropping sequences under no tillage (NT), (ii) to compare the information generated from the lines with the same PR values with the analysis of the cultural profile and (iii) to study the spatial variability in the PR and the bulk density (BD) in a 10-ha plot, and their relationship with soybean crop yield. An experiment was carried out in an Aquic Argiudoll in 100-m2 plots (4 m wide x 25 m long), with different long-term cropping sequences, under NT for 15 years. The treatments tested were: soybean and maize monocultures, wheat/soybean, wheat/soybean-maize and a permanent pasture as a reference. A digital penetrologger Eijkelkamp ® was used to take 20 measurements of the PR in each plot, through the design of a grid 5 m long and 0.66 m wide, centimeter-wise until 20 cm, totaling n= 400. In addition, an observation well (1 m wide by 30 cm deep) was analyzed by means of the technique of the cultural profiles. Besides, two sampling grids in a 10-ha plot with maize-wheat/soybean sequence were used to measure PR every 30 m and BD every 60 m. The variability in the soil properties was assessed using descriptive statistical analysis, determining normality and spatial variability with the adjustment to the theoretical semivariograms. At 10-15 and 15-20 cm, wheat/soybean-maize and wheat/soybean showed the highest PR values, differentiating from the soybeans and maize monocultures and pasture. The lines with the same PR values allowed observing structural changes in the soil profile, such as surface granular structures and subsequent layers of laminar structure, sometimes discontinuous, from 1.0 to 1.5 MPa between 5 and 8 cm in depth, and

  7. Bacillus thuringiensis insecticidal three-domain Cry toxins: mode of action, insect resistance and consequences for crop protection.

    PubMed

    Pardo-López, Liliana; Soberón, Mario; Bravo, Alejandra

    2013-01-01

    Bacillus thuringiensis bacteria are insect pathogens that produce different Cry and Cyt toxins to kill their hosts. Here we review the group of three-domain Cry (3d-Cry) toxins. Expression of these 3d-Cry toxins in transgenic crops has contributed to efficient control of insect pests and a reduction in the use of chemical insecticides. The mode of action of 3d-Cry toxins involves sequential interactions with several insect midgut proteins that facilitate the formation of an oligomeric structure and induce its insertion into the membrane, forming a pore that kills midgut cells. We review recent progress in our understanding of the mechanism of action of these Cry toxins and focus our attention on the different mechanisms of resistance that insects have evolved to counter their action, such as mutations in cadherin, APN and ABC transporter genes. Activity of Cry1AMod toxins, which are able to form toxin oligomers in the absence of receptors, against different resistant populations, including those affected in the ABC transporter and the role of dominant negative mutants as antitoxins, supports the hypothesis that toxin oligomerization is a limiting step in the Cry insecticidal activity. Knowledge of the action of 3d-Cry toxin and the resistance mechanisms to these toxins will set the basis for a rational design of novel toxins to overcome insect resistance, extending the useful lifespan of Cry toxins in insect control programs.

  8. Preparation and ageing-resistant properties of polyester composites modified with functional nanoscale additives

    PubMed Central

    2014-01-01

    This study investigated ageing-resistant properties of carboxyl-terminated polyester (polyethylene glycol terephthalate) composites modified with nanoscale titanium dioxide particles (nano-TiO2). The nano-TiO2 was pretreated by a dry coating method, with aluminate coupling agent as a functional grafting additive. The agglomeration resistance was evaluated, which exhibited significant improvement for the modified nanoparticles. Then, the effects of the modified nano-TiO2 on the crosslinking and ageing-resistant properties of the composites were studied. With a real-time Fourier transform infrared (FT-IR) measurement, the nano-TiO2 displayed promoting effect on the crosslinking of polyester resin with triglycidyl isocyanurate (TGIC) as crosslinking agent. Moreover, the gloss retention, colour aberration and the surface morphologies of the composites during accelerated UV ageing (1500 hours) were investigated. The results demonstrated much less degree of ageing degradation for the nanocomposites, indicating an important role of the nano-TiO2 in improving the ageing-resistant properties of synthetic polymer composites. PMID:24872802

  9. Responses of plants and invertebrate trophic groups to contrasting herbicide regimes in the Farm Scale Evaluations of genetically modified herbicide-tolerant crops.

    PubMed Central

    Hawes, C; Haughton, A J; Osborne, J L; Roy, D B; Clark, S J; Perry, J N; Rothery, P; Bohan, D A; Brooks, D R; Champion, G T; Dewar, A M; Heard, M S; Woiwod, I P; Daniels, R E; Young, M W; Parish, A M; Scott, R J; Firbank, L G; Squire, G R

    2003-01-01

    Effects of genetically modified herbicide-tolerant (GMHT) and conventional crop management on invertebrate trophic groups (herbivores, detritivores, pollinators, predators and parasitoids) were compared in beet, maize and spring oilseed rape sites throughout the UK. These trophic groups were influenced by season, crop species and GMHT management. Many groups increased twofold to fivefold in abundance between early and late summer, and differed up to 10-fold between crop species. GMHT management superimposed relatively small (less than twofold), but consistent, shifts in plant and insect abundance, the extent and direction of these effects being dependent on the relative efficacies of comparable conventional herbicide regimes. In general, the biomass of weeds was reduced under GMHT management in beet and spring oilseed rape and increased in maize compared with conventional treatments. This change in resource availability had knock-on effects on higher trophic levels except in spring oilseed rape where herbivore resource was greatest. Herbivores, pollinators and natural enemies changed in abundance in the same directions as their resources, and detritivores increased in abundance under GMHT management across all crops. The result of the later herbicide application in GMHT treatments was a shift in resource from the herbivore food web to the detritivore food web. The Farm Scale Evaluations have demonstrated over 3 years and throughout the UK that herbivores, detritivores and many of their predators and parasitoids in arable systems are sensitive to the changes in weed communities that result from the introduction of new herbicide regimes. PMID:14561321

  10. Recombinase Polymerase Amplification (RPA) of CaMV-35S Promoter and nos Terminator for Rapid Detection of Genetically Modified Crops

    PubMed Central

    Xu, Chao; Li, Liang; Jin, Wujun; Wan, Yusong

    2014-01-01

    Recombinase polymerase amplification (RPA) is a novel isothermal DNA amplification and detection technology that enables the amplification of DNA within 30 min at a constant temperature of 37–42 °C by simulating in vivo DNA recombination. In this study, based on the regulatory sequence of the cauliflower mosaic virus 35S (CaMV-35S) promoter and the Agrobacterium tumefaciens nopaline synthase gene (nos) terminator, which are widely incorporated in genetically modified (GM) crops, we designed two sets of RPA primers and established a real-time RPA detection method for GM crop screening and detection. This method could reliably detect as few as 100 copies of the target molecule in a sample within 15–25 min. Furthermore, the real-time RPA detection method was successfully used to amplify and detect DNA from samples of four major GM crops (maize, rice, cotton, and soybean). With this novel amplification method, the test time was significantly shortened and the reaction process was simplified; thus, this method represents an effective approach to the rapid detection of GM crops. PMID:25310647

  11. Invertebrate responses to the management of genetically modified herbicide-tolerant and conventional spring crops. I. Soil-surface-active invertebrates.

    PubMed Central

    Brooks, D R; Bohan, D A; Champion, G T; Haughton, A J; Hawes, C; Heard, M S; Clark, S J; Dewar, A M; Firbank, L G; Perry, J N; Rothery, P; Scott, R J; Woiwod, I P; Birchall, C; Skellern, M P; Walker, J H; Baker, P; Bell, D; Browne, E L; Dewar, A J G; Fairfax, C M; Garner, B H; Haylock, L A; Horne, S L; Hulmes, S E; Mason, N S; Norton, L R; Nuttall, P; Randle, Z; Rossall, M J; Sands, R J N; Singer, E J; Walker, M J

    2003-01-01

    The effects of herbicide management of genetically modified herbicide-tolerant (GMHT) beet, maize and spring oilseed rape on the abundance and diversity of soil-surface-active invertebrates were assessed. Most effects did not differ between years, environmental zones or initial seedbanks or between sugar and fodder beet. This suggests that the results may be treated as generally applicable to agricultural situations throughout the UK for these crops. The direction of the effects was evenly balanced between increases and decreases in counts in the GMHT compared with the conventional treatment. Most effects involving a greater capture in the GMHT treatments occurred in maize, whereas most effects involving a smaller capture were in beet and spring oilseed rape. Differences between GMHT and conventional crop herbicide management had a significant effect on the capture of most surface-active invertebrate species and higher taxa tested in at least one crop, and these differences reflected the phenology and ecology of the invertebrates. Counts of carabids that feed on weed seeds were smaller in GMHT beet and spring oilseed rape but larger in GMHT maize. In contrast, collembolan detritivore counts were significantly larger under GMHT crop management. PMID:14561318

  12. Recombinase polymerase amplification (RPA) of CaMV-35S promoter and nos terminator for rapid detection of genetically modified crops.

    PubMed

    Xu, Chao; Li, Liang; Jin, Wujun; Wan, Yusong

    2014-10-10

    Recombinase polymerase amplification (RPA) is a novel isothermal DNA amplification and detection technology that enables the amplification of DNA within 30 min at a constant temperature of 37-42 °C by simulating in vivo DNA recombination. In this study, based on the regulatory sequence of the cauliflower mosaic virus 35S (CaMV-35S) promoter and the Agrobacterium tumefaciens nopaline synthase gene (nos) terminator, which are widely incorporated in genetically modified (GM) crops, we designed two sets of RPA primers and established a real-time RPA detection method for GM crop screening and detection. This method could reliably detect as few as 100 copies of the target molecule in a sample within 15-25 min. Furthermore, the real-time RPA detection method was successfully used to amplify and detect DNA from samples of four major GM crops (maize, rice, cotton, and soybean). With this novel amplification method, the test time was significantly shortened and the reaction process was simplified; thus, this method represents an effective approach to the rapid detection of GM crops.

  13. Overexpression of a Modified Plant Thionin Enhances Disease Resistance to Citrus Canker and Huanglongbing (HLB)

    PubMed Central

    Hao, Guixia; Stover, Ed; Gupta, Goutam

    2016-01-01

    Huanglongbing (HLB or citrus greening disease) caused by Candidatus Liberibacter asiaticus (Las) is a great threat to the US citrus industry. There are no proven strategies to eliminate HLB disease and no cultivar has been identified with strong HLB resistance. Citrus canker is also an economically important disease associated with a bacterial pathogen (Xanthomonas citri). In this study, we characterized endogenous citrus thionins and investigated their expression in different citrus tissues. Since no HLB-resistant citrus cultivars have been identified, we attempted to develop citrus resistant to both HLB and citrus canker through overexpression of a modified plant thionin. To improve effectiveness for disease resistance, we modified and synthesized the sequence encoding a plant thionin and cloned into the binary vector pBinPlus/ARS. The construct was then introduced into Agrobacterium strain EHA105 for citrus transformation. Transgenic Carrizo plants expressing the modified plant thionin were generated by Agrobacterium-mediated transformation. Successful transformation and transgene gene expression was confirmed by molecular analysis. Transgenic Carrizo plants expressing the modified thionin gene were challenged with X. citri 3213 at a range of concentrations, and a significant reduction in canker symptoms and a decrease in bacterial growth were demonstrated compared to nontransgenic plants. Furthermore, the transgenic citrus plants were challenged with HLB via graft inoculation. Our results showed significant Las titer reduction in roots of transgenic Carrizo compared with control plants and reduced scion Las titer 12 months after graft inoculation. These data provide promise for engineering citrus disease resistance against HLB and canker. PMID:27499757

  14. Novel antimicrobial peptide–modified azithromycin-loaded liposomes against methicillin-resistant Staphylococcus aureus

    PubMed Central

    Liu, Xiaowei; Li, Zhan; Wang, Xiaodong; Chen, Yujuan; Wu, Fengbo; Men, Ke; Xu, Ting; Luo, Yan; Yang, Li

    2016-01-01

    Infections caused by multidrug-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), have become a public threat; therefore, development of new antimicrobial drugs or strategies is urgently required. In this study, a new antibacterial peptide DP7-C (Chol-suc-VQWRIRVAVIRK-NH2) and DP7-C-modified azithromycin (AZT)-loaded liposomes (LPs) are developed for the treatment of MRSA infection, and it was found that DP7-C inserted into the LP lipid bilayer not only functioned as a carrier to encapsulate the antibiotic AZT but also synergized the antibacterial effect of the encapsulated AZT. In vitro assays showed that DP7-C-modified LPs possessed sustained drug release profile and immune regulatory effect and did not show obvious cytotoxicity in mammal cells, but they did not possess direct antibacterial activity in vitro. In vivo studies revealed that DP7-C-modified LPs did not exhibit obvious side effects or toxicity in mice but were able to significantly reduce the bacterial counts in an MRSA-infectious mouse model and possessed high antibacterial activity. In particular, DP7-C-modified AZT-loaded LPs showed more positive therapeutic effects than either DP7-C-modified blank LPs or nonmodified AZT-loaded LPs treatment alone. Molecular mechanism studies demonstrated that DP7-C formulations effectively upregulated the production of anti-inflammatory cytokines and chemokines without inducing harmful immune response, suggesting that DP7-C was synergistic with AZT against the bacterial infection by activating the innate immune response. Most importantly, although DP7-C activated the innate immune response, it did not possess direct antibacterial activity in vitro, indicating that DP7-C did not possess the potential to induce bacteria resistance. The findings indicate that DP7-C-modified AZT-loaded LPs developed in this study have a great potential required for the clinical treatment of MRSA infections. PMID:28008253

  15. Efficacy of Genetically Modified Bt Toxins Alone and in Combinations Against Pink Bollworm Resistant to Cry1Ac and Cry2Ab

    PubMed Central

    Tabashnik, Bruce E.; Fabrick, Jeffrey A.; Unnithan, Gopalan C.; Yelich, Alex J.; Masson, Luke; Zhang, Jie; Bravo, Alejandra; Soberón, Mario

    2013-01-01

    Evolution of resistance in pests threatens the long-term efficacy of insecticidal proteins from Bacillus thuringiensis (Bt) used in sprays and transgenic crops. Previous work showed that genetically modified Bt toxins Cry1AbMod and Cry1AcMod effectively countered resistance to native Bt toxins Cry1Ab and Cry1Ac in some pests, including pink bollworm (Pectinophora gossypiella). Here we report that Cry1AbMod and Cry1AcMod were also effective against a laboratory-selected strain of pink bollworm resistant to Cry2Ab as well as to Cry1Ab and Cry1Ac. Resistance ratios based on the concentration of toxin killing 50% of larvae for the resistant strain relative to a susceptible strain were 210 for Cry2Ab, 270 for Cry1Ab, and 310 for Cry1Ac, but only 1.6 for Cry1AbMod and 2.1 for Cry1AcMod. To evaluate the interactions among toxins, we tested combinations of Cry1AbMod, Cry1Ac, and Cry2Ab. For both the resistant and susceptible strains, the net results across all concentrations tested showed slight but significant synergism between Cry1AbMod and Cry2Ab, whereas the other combinations of toxins did not show consistent synergism or antagonism. The results suggest that the modified toxins might be useful for controlling populations of pink bollworm resistant to Cry1Ac, Cry2Ab, or both. PMID:24244692

  16. The present state of research and exploitation of biotech (GM) crops in horticulture: results of research on plum cv. 'HoneySweet' resistant to plum pox virus (Sharka) and the deregulation of this cultivar in the CR & Europe

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gentically modified (GM) crops were grown world-wide on 160 million ha in 2011. Only 114.57 ha of GM crops were grown in Europe, of that, 114.90 ha were Bt maize and 17 ha were potato for industrial starch production. Commercialization of Biotech crops started in 1995. Currently, developing count...

  17. Specific detection of benzimidazole resistance in Colletotrichum gloeosporioides from fruit crops by PCR-RFLP.

    PubMed

    Chung, Wen-Hsin; Chung, Wen-Chuan; Peng, Mun-Tsu; Yang, Hong-Ren; Huang, Jenn-Wen

    2010-02-28

    Anthracnose diseases, caused by Colletotrichum gloeosporioides, are a worldwide problem and are especially important in Taiwan owing to the severe economic damage they cause to tropical fruits that are grown for local consumption and export. Benzimidazoles are systemic fungicides widely used for controlling these diseases in Taiwan. Thirty-one isolates of C. gloeosporioides from mango and strawberry grown in Taiwan were examined for their sensitivity to benzimidazole fungicides. The responses of the isolates grown on benzimidazole-amended culture media were characterized as sensitive, moderately resistant, resistant or highly resistant. Analysis of point mutations in the beta-tubulin gene by DNA sequencing of PCR-amplified fragments revealed a substitution of GCG for GAG at codon 198 in resistant and highly resistant isolates and a substitution of TAC for TTC at codon 200 in moderately resistant isolates. A set of specific primers, TubGF1 and TubGR, was designed to amplify a portion of the beta-tubulin gene for the detection of benzimidazole-resistant C. gloeosporioides. Bsh1236I restriction maps of the amplified beta-tubulin gene showed that the resistant isolate sequence, but not the sensitive isolate sequence, was cut. The PCR restriction fragment length polymorphism (PCR-RFLP) was validated to detect benzimidazole-resistant and benzimidazole-sensitive C. gloeosporioides isolates recovered from avocado, banana, carambola, dragon fruit, grape, guava, jujube, lychee, papaya, passion fruit and wax apple. This method has the potential to become a valuable tool for monitoring the occurrence of benzimidazole-resistant C. gloeosporioides and for assessment of the need for alternative management practices.

  18. A strategy to provide long-term control of weedy rice while mitigating herbicide resistance transgene flow, and its potential use for other crops with related weeds.

    PubMed

    Gressel, Jonathan; Valverde, Bernal E

    2009-07-01

    Transgenic herbicide-resistant rice is needed to control weeds that have evolved herbicide resistance, as well as for the weedy (feral, red) rice problem, which has been exacerbated by shifting to direct seeding throughout the world-firstly in Europe and the Americas, and now in Asia, as well as in parts of Africa. Transplanting had been the major method of weedy rice control. Experience with imidazolinone-resistant rice shows that gene flow to weedy rice is rapid, negating the utility of the technology. Transgenic technologies are available that can contain herbicide resistance within the crop (cleistogamy, male sterility, targeting to chloroplast genome, etc.), but such technologies are leaky. Mitigation technologies tandemly couple (genetically link) the gene of choice (herbicide resistance) with mitigation genes that are neutral or good for the crop, but render hybrids with weedy rice and their offspring unfit to compete. Mitigation genes confer traits such as non-shattering, dwarfism, no secondary dormancy and herbicide sensitivity. It is proposed to use glyphosate and glufosinate resistances separately as genes of choice, and glufosinate, glyphosate and bentazone susceptibilities as mitigating genes, with a six-season rotation where each stage kills transgenic crop volunteers and transgenic crop x weed hybrids from the previous season.

  19. Comparison of herbicide regimes and the associated potential environmental effects of glyphosate-resistant crops versus what they replace in Europe.

    PubMed

    Kleter, Gijs A; Harris, Caroline; Stephenson, Gerry; Unsworth, John

    2008-04-01

    While cultivation of transgenic crops takes place in seven of the EU member states, this constitutes a relatively limited part of the total acreage planted to these crops worldwide. The only glyphosate-resistant (GR) crop grown commercially until recently has been soybean in Romania. In addition, large-scale experimental European data exist for GR sugar and fodder beets, and, to a lesser extent, GR oilseed rape. These GR crops are likely to have an impact both on the use of herbicides and on the environmental impact of the latter. From the data on these GR crops, it appears that quantities of herbicides applied to GR beets are decreased while those on GR soybean are slightly increased compared with their conventional counterparts. Depending on the parameters used for prediction or measurement of environmental impacts of GR crops, generally similar or less negative impacts were observed compared with conventional crops. Favourable environmental effects of the glyphosate-containing herbicide regimes on GR crops appear feasible, provided appropriate measures for maintaining biodiversity and prevention of volunteers and gene flow are applied.

  20. Less waste corn, more land in soybeans, and the switch to genetically modified crops: trends with important implications to wildlife management

    USGS Publications Warehouse

    Krapu, G.L.; Brandt, D.A.; Cox, R.R.

    2004-01-01

    An abundance of waste corn, a key food of many wildlife species, has helped make possible the widespread success of wildlife management in the United States over the past half century. We found waste corn post harvest in Nebraska declined by 47% from 1978 to 1998 due primarily to improvements in combine headers resulting in a marked decline in ear loss. The reduction in waste coincided with major declines in fat storage by sandhill cranes and white-fronted geese during spring migration. Sandhill cranes, northern pintails, white-fronted geese, and lesser snow geese avoided soybeans while staging in spring in the Rainwater Basin Area and Central Platte River Valley. These findings and other literature suggest soybeans are a marginal food for wildlife particularly during periods of high energy requirements. Soybean acreage has increased by 600% in the United States since 1950 and now comprises nearly one-quarter of the nation>'s cropland. With over 80% of the soybean crop now in genetically modified varieties and treated with glyphosate, weed seed is becoming scarce in soybean fields leaving limited food for wildlife on 72 million acres of U.S. cropland. We suggest that the combined effect of increasing efficiency of crop harvesting techniques, expansion of soybeans and other crops poorly suited for wildlife nutrient needs, and more efficient weed control through the shift to genetically modified crops may severely limit seed-eating wildlife populations in the future unless ways are found to replace high energy food sources being lost. We encourage more research to gain greater insight into effects of declining food resources on wildlife populations and propose that the conservation title of the 2002 farm bill be used as a mechanism to replace part of the high-energy food being lost due to changes in production agriculture.

  1. Does Cardiorespiratory Fitness Modify the Association between Birth Weight and Insulin Resistance in Adult Life?

    PubMed Central

    Aoyama, Tomoko; Tsushita, Kazuyo; Miyatake, Nobuyuki; Numata, Takeyuki; Miyachi, Motohiko; Tabata, Izumi; Cao, Zhen-Bo; Sakamoto, Shizuo; Higuchi, Mitsuru

    2013-01-01

    Objective Lower birth weight is associated with higher insulin resistance in later life. The aim of this study was to determine whether cardiorespiratory fitness modifies the association of birth weight with insulin resistance in adults. Methods The subjects were 379 Japanese individuals (137 males, 242 females) aged 20–64 years born after 1943. Insulin resistance was assessed using a homeostasis model assessment of insulin resistance (HOMA-IR), which is calculated from fasting blood glucose and insulin levels. Cardiorespiratory fitness (maximal oxygen uptake, VO2max) was assessed by a maximal graded exercise test on a cycle ergometer. Birth weight was reported according to the Maternal and Child Health Handbook records or the subject’s or his/her mother’s memory. Results The multiple linear regression analysis revealed that birth weight was inversely associated with HOMA-IR (β = −0.141, p = 0.003), even after adjustment for gender, age, current body mass index, mean blood pressure, triglycerides, HDL cholesterol, and smoking status. Further adjustments for VO2max made little difference in the relationship between birth weight and HOMA-IR (β = −0.148, p = 0.001), although VO2max (β = −0.376, p<0.001) was a stronger predictor of HOMA-IR than birth weight. Conclusions The results showed that the association of lower birth weight with higher insulin resistance was little modified by cardiorespiratory fitness in adult life. However, cardiorespiratory fitness was found to be a stronger predictor of insulin resistance than was birth weight, suggesting that increasing cardiorespiratory fitness may have a much more important role in preventing insulin resistance than an individual’s low birth weight. PMID:24069257

  2. Transgenes for insect resistance reduce herbivory and enhance fecundity in advanced generations of crop-weed hybrids of rice.

    PubMed

    Yang, Xiao; Xia, Hui; Wang, Wei; Wang, Feng; Su, Jun; Snow, Allison A; Lu, Bao-Rong

    2011-09-01

    Gene flow from transgenic crops allows novel traits to spread to sexually compatible weeds. Traits such as resistance to insects may enhance the fitness of weeds, but few studies have tested for these effects under natural field conditions. We created F 2 and F 3 crop-weed hybrid lineages of genetically engineered rice (Oryza sativa) using lines with two transgene constructs, cowpea trypsin inhibitor (CpTI) and a Bt transgene linked to CpTI (Bt/CpTI). Experiments conducted in Fuzhou, China, demonstrated that CpTI alone did not significantly affect fecundity, although it reduced herbivory. In contrast, under certain conditions, Bt/CpTI conferred up to 79% less insect damage and 47% greater fecundity relative to nontransgenic controls, and a 44% increase in fecundity relative to the weedy parent. A small fitness cost was detected in F 3 progeny with Bt/CpTI when grown under low insect pressure and direct competition with transgene-negative controls. We conclude that Bt/CpTI transgenes may introgress into co-occurring weedy rice populations and contribute to greater seed production when target insects are abundant. However, the net fitness benefits that are associated with Bt/CpTI could be ephemeral if insect pressure is lacking, for example, because of widespread planting of Bt cultivars that suppress target insect populations.

  3. Limited Fitness Advantages of Crop-Weed Hybrid Progeny Containing Insect-Resistant Transgenes (Bt/CpTI) in Transgenic Rice Field

    PubMed Central

    Yang, Xiao; Wang, Feng; Su, Jun; Lu, Bao-Rong

    2012-01-01

    Background The spread of insect-resistance transgenes from genetically engineered (GE) rice to its coexisting weedy rice (O. sativa f. spontanea) populations via gene flow creates a major concern for commercial GE rice cultivation. Transgene flow to weedy rice seems unavoidable. Therefore, characterization of potential fitness effect brought by the transgenes is essential to assess environmental consequences caused by crop-weed transgene flow. Methodology/Principal Findings Field performance of fitness-related traits was assessed in advanced hybrid progeny of F4 generation derived from a cross between an insect-resistant transgenic (Bt/CpTI) rice line and a weedy strain. The performance of transgene-positive hybrid progeny was compared with the transgene-negative progeny and weedy parent in pure and mixed planting of transgenic and nontransgenic plants under environmental conditions with natural vs. low insect pressure. Results showed that under natural insect pressure the insect-resistant transgenes could effectively suppress target insects and bring significantly increased fitness to transgenic plants in pure planting, compared with nontransgenic plants (including weedy parent). In contrast, no significant differences in fitness were detected under low insect pressure. However, such increase in fitness was not detected in the mixed planting of transgenic and nontransgenic plants due to significantly reduced insect pressure. Conclusions/Significance Insect-resistance transgenes may have limited fitness advantages to hybrid progeny resulted from crop-weed transgene flow owning to the significantly reduced ambient target insect pressure when an insect-resistant GE crop is grown. Given that the extensive cultivation of an insect-resistant GE crop will ultimately reduce the target insect pressure, the rapid spread of insect-resistance transgenes in weedy populations in commercial GE crop fields may be not likely to happen. PMID:22815975

  4. Modified two-fluid model of conductivity for superconducting surface resistance calculation. Master's thesis

    SciTech Connect

    Linden, D.S.

    1993-05-01

    The traditional two-fluid model of superconducting conductivity was modified to make it accurate, while remaining fast, for designing and simulating microwave devices. The modification reflects the BCS coherence effects in the conductivity of a superconductor, and is incorporated through the ratio of normal to superconducting electrons. This modified ratio is a simple analytical expression which depends on frequency, temperature and material parameters. This modified two-fluid model allows accurate and rapid calculation of the microwave surface impedance of a superconductor in the clean and dirty limits and in the weak- and strong-coupled regimes. The model compares well with surface resistance data for Nb and provides insight into Nb3Sn and Y1Ba2Cu3O(7-delta). Numerical calculations with the modified two-fluid model are an order of magnitude faster than the quasi-classical program by Zimmermann (1), and two to five orders of magnitude faster than Halbritter's BCS program (2) for surface resistance.

  5. Comparative Effectiveness of Potential Elicitors of Plant Resistance against Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) in Four Crop Plants

    PubMed Central

    Gordy, John W.; Leonard, B. Rogers; Blouin, David; Davis, Jeffrey A.; Stout, Michael J.

    2015-01-01

    Feeding by insect herbivores activates plant signaling pathways, resulting in the enhanced production of secondary metabolites and other resistance-related traits by injured plants. These traits can reduce insect fitness, deter feeding, and attract beneficial insects. Organic and inorganic chemicals applied as a foliar spray, seed treatment, or soil drench can activate these plant responses. Azelaic acid (AA), benzothiadiazole (BTH), gibberellic acid (GA), harpin, and jasmonic acid (JA) are thought to directly mediate plant responses to pathogens and herbivores or to mimic compounds that do. The effects of these potential elicitors on the induction of plant defenses were determined by measuring the weight gains of fall armyworm, Spodoptera frugiperda (J. E. Smith) (FAW) (Lepidoptera: Noctuidae) larvae on four crop plants, cotton, corn, rice, and soybean, treated with the compounds under greenhouse conditions. Treatment with JA consistently reduced growth of FAW reared on treated cotton and soybean. In contrast, FAW fed BTH- and harpin-treated cotton and soybean tissue gained more weight than those fed control leaf tissue, consistent with negative crosstalk between the salicylic acid and JA signaling pathways. No induction or inconsistent induction of resistance was observed in corn and rice. Follow-up experiments showed that the co-application of adjuvants with JA failed to increase the effectiveness of induction by JA and that soybean looper [Chrysodeixis includens (Walker)], a relative specialist on legumes, was less affected by JA-induced responses in soybean than was the polyphagous FAW. Overall, the results of these experiments demonstrate that the effectiveness of elicitors as a management tactic will depend strongly on the identities of the crop, the pest, and the elicitor involved. PMID:26332833

  6. Thai ethnomedicinal plants as resistant modifying agents for combating Acinetobacter baumannii infections

    PubMed Central

    2012-01-01

    Abstracts Background Acinetobacter baumannii is well-recognized as an important nosocomial pathogen, however, due to their intrinsic resistance to several antibiotics, treatment options are limited. Synergistic effects between antibiotics and medicinal plants, particularly their active components, have intensively been studied as alternative approaches. Methods Fifty-one ethanol extracts obtained from 44 different selected medicinal plant species were tested for resistance modifying agents (RMAs) of novobiocin against A. baumannii using growth inhibition assay. Results At 250 μg/ml, Holarrhena antidysenterica, Punica granatum, Quisqualis indica, Terminalia bellirica, Terminalia chebula, and Terminalia sp. that possessed low intrinsic antibacterial activity significantly enhanced the activity of novobiocin at 1 μg/ml (1/8xminimum inhibitory concentration) against this pathogen. Holarrhena antidysenterica at 7.8 μg/ml demonstrated remarkable resistant modifying ability against A. baumannii in combination with novobiocin. The phytochemical study revealed that constituents of this medicinal plant contain alkaloids, condensed tannins, and triterpenoids. Conclusion The use of Holarrhena antidysenterica in combination with novobiocin provides an effective alternative treatment for multidrug resistant A. baumannii infections. PMID:22536985

  7. Changes in the Chemical Composition and Decay Resistance of Thermally-Modified Hevea brasiliensis Wood

    PubMed Central

    2016-01-01

    In this study the effect of thermal treatment on the equilibrium moisture content, chemical composition and biological resistance to decay fungi of juvenile and mature Hevea brasiliensis wood (rubber wood) was evaluated. Samples were taken from a 53-year-old rubber wood plantation located in Tabapuã, Sao Paulo, Brazil. The samples were thermally-modified at 180°C, 200°C and 220°C. Results indicate that the thermal modification caused: (1) a significant increase in the extractive content and proportional increase in the lignin content at 220°C; (2) a significant decrease in the equilibrium moisture content, holocelluloses, arabinose, galactose and xylose content, but no change in glucose content; and (3) a significant increase in wood decay resistance against both Pycnoporus sanguineus (L.) Murrill and Gloeophyllum trabeum (Pers.) Murrill decay fungi. The greatest decay resistance was achieved from treatment at 220°C which resulted in a change in wood decay resistance class from moderately resistant to resistant. Finally, this study also demonstrated that the influence of thermal treatment in mature wood was lower than in juvenile wood. PMID:26986200

  8. Changes in the Chemical Composition and Decay Resistance of Thermally-Modified Hevea brasiliensis Wood.

    PubMed

    Severo, Elias Taylor Durgante; Calonego, Fred Willians; Sansígolo, Cláudio Angeli; Bond, Brian

    2016-01-01

    In this study the effect of thermal treatment on the equilibrium moisture content, chemical composition and biological resistance to decay fungi of juvenile and mature Hevea brasiliensis wood (rubber wood) was evaluated. Samples were taken from a 53-year-old rubber wood plantation located in Tabapuã, Sao Paulo, Brazil. The samples were thermally-modified at 180°C, 200°C and 220°C. Results indicate that the thermal modification caused: (1) a significant increase in the extractive content and proportional increase in the lignin content at 220°C; (2) a significant decrease in the equilibrium moisture content, holocelluloses, arabinose, galactose and xylose content, but no change in glucose content; and (3) a significant increase in wood decay resistance against both Pycnoporus sanguineus (L.) Murrill and Gloeophyllum trabeum (Pers.) Murrill decay fungi. The greatest decay resistance was achieved from treatment at 220°C which resulted in a change in wood decay resistance class from moderately resistant to resistant. Finally, this study also demonstrated that the influence of thermal treatment in mature wood was lower than in juvenile wood.

  9. Modified ferritic iron alloys with improved high-temperature mechanical properties and oxidation resistance

    NASA Technical Reports Server (NTRS)

    Oldrieve, R. E.

    1975-01-01

    An alloy modification program was conducted in which the compositions of two existing Fe-Cr-Al alloys (Armco 18SR and GE-1541) were changed to achieve either improved high-temperature strength or improved fabricability. Only modifications of Armco 18SR were successful in achieving increased strength without loss of fabricability or oxidation resistance. The best modified alloy, designated NASA-18T, had twice the rupture strength of Armco 18SR at 800 and 1000 C. The NASA-18T alloy also had better oxidation resistance than Armco 18SR and comparable fabricability. The nominal composition of NASA-18T is Fe-18Cr-2Al-1Si-1.25Ta. All attempted modifications of the GE-1541 alloy were unsuccessful in terms of achieving better fabricability without sacrificing high-temperature strength and oxidation resistance.

  10. The citric acid-modified, enzyme-resistant dextrin from potato starch as a potential prebiotic.

    PubMed

    Sliżewska, Katarzyna

    2013-01-01

    In the present study, enzyme-resistant dextrin, prepared by heating of potato starch in the presence of hydrochloric (0.1% dsb) and citric (0.1% dsb) acid at 130ºC for 3 h (CA-dextrin), was tested as a source of carbon for probiotic lactobacilli and bifidobacteria cultured with intestinal bacteria isolated from feces of three healthy 70-year old volunteers. The dynamics of growth of bacterial monocultures in broth containing citric acid (CA)-modified dextrin were estimated. It was also investigated whether lactobacilli and bifidobacteria cultured with intestinal bacteria in the presence of resistant dextrin would be able to dominate the intestinal isolates. Prebiotic fermentation of resistant dextrin was analyzed using prebiotic index (PI). In co-cultures of intestinal and probiotic bacteria, the environment was found to be dominated by the probiotic strains of Bifidobacterium and Lactobacillus, which is a beneficial effect.

  11. Interactions of tillage and cover crop on runoff water quality from glyphosate-resistant cotton systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conservation management systems need to be optimized for glyphosate [N-(phosphonomethyl)glycine]-resistant cotton (Gossypium hirsutum L.) (GRC) in the lower Mississippi River alluvial basin to balance production goals with environmental concerns. A rainfall simulation study was conducted in experim...

  12. Genomic tools for developing markers for postharvest disease resistance in Rosaceae fruit crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A wealth of new plant genomic information and molecular tools have been developed over the past ten years and now the challenge is to learn how to apply this information to address critical production problems, such as disease resistance and abiotic stress tolerance. Malus sieversii, an apple speci...

  13. Enhanced pest resistance of maize leaves expressing monocot crop plant derived ribosome inactivating protein and agglutinin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although many insect resistance genes have been identified, the number of studies examining their effects in combination using transgenic systems is limited. We introduced a construct into maize containing the coding sequence for maize ribosome inactivating protein (MRIP), wheat germ agglutinin (WGA...

  14. High residue cover crops alone or with strategic tillage to manage glyphosate-resistant palmer amaranth (amaranthus palmeri) in Southeastern cotton (gossypium hirsutum)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glyphosate-resistant (GR) Palmer amaranth (Amaranthus palmeri S. Wats) is redefining row crop weed management in the Southeast due to its widespread distribution, high competitive ability, copious seed production, and resilience to standard weed management programs. Herbicides alone are failing to p...

  15. Late-season grass weed management with in-crop and post-harvest herbicides in twin-row glyphosate-resistant soybean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A 3-yr field study was conducted from 2011 to 2013 at Stoneville, MS to determine efficacy of post-harvest and pyroxasulfone-based in-crop herbicides on late-season grasses and yield in twin-row glyphosate-resistant (GR) soybean. Experiments were conducted in a split-plot arrangement of treatments i...

  16. Allergenicity Assessment of Allium sativum Leaf Agglutinin, a Potential Candidate Protein for Developing Sap Sucking Insect Resistant Food Crops

    PubMed Central

    Mondal, Hossain Ali; Chakraborti, Dipankar; Majumder, Pralay; Roy, Pampa; Roy, Amit; Bhattacharya, Swati Gupta; Das, Sampa

    2011-01-01

    Background Mannose-binding Allium sativum leaf agglutinin (ASAL) is highly antinutritional and toxic to various phloem-feeding hemipteran insects. ASAL has been expressed in a number of agriculturally important crops to develop resistance against those insects. Awareness of the safety aspect of ASAL is absolutely essential for developing ASAL transgenic plants. Methodology/Principal Findings Following the guidelines framed by the Food and Agriculture Organization/World Health Organization, the source of the gene, its sequence homology with potent allergens, clinical tests on mammalian systems, and the pepsin resistance and thermostability of the protein were considered to address the issue. No significant homology to the ASAL sequence was detected when compared to known allergenic proteins. The ELISA of blood sera collected from known allergy patients also failed to show significant evidence of cross-reactivity. In vitro and in vivo assays both indicated the digestibility of ASAL in the presence of pepsin in a minimum time period. Conclusions/Significance With these experiments, we concluded that ASAL does not possess any apparent features of an allergen. This is the first report regarding the monitoring of the allergenicity of any mannose-binding monocot lectin having insecticidal efficacy against hemipteran insects. PMID:22110739

  17. Effects of a new modifier on the water-resistance of magnesite cement tiles

    NASA Astrophysics Data System (ADS)

    Xu, Kejing; Xi, Jintao; Guo, Yanqing; Dong, Shuhua

    2012-01-01

    The magnesium oxychloride composite is an inorganic cementitious material with high bending and compression strength in air characteristics. However its strength decreases significantly after immersion in water. The preparing process of a new magnesite cement tile using nano rice husk ashes and a complex water-resistance agent as modifiers was described in the paper. The effects of low-temperature rice husk ashes (RHAs) and the complex water-resistance agent constituted with phosphoric acid, calcium superphosphate, wooden calcium and styrene-acrylic emulsion on the water-resistance of magnesite materials were mainly studied. The samples properties were characterized by XRD, SEM, BET, a laser particle size analyzer and bending test. The experiments show that the proportional addition of nano RHAs markedly increases the water-resistance of magnesite materials without reducing the bending strength and promotes the softening coefficient from 0.29 to 0.78, while the softening coefficient reaches up to 0.97 combined with the use of complex water-resistance agent. The new magnesite cement tiles prepared were not scumming, not warping, and not contracting at room temperature for 360 d.

  18. Particle-by-Particle Charge Analysis of DNA-Modified Nanoparticles Using Tunable Resistive Pulse Sensing.

    PubMed

    Blundell, Emma L C J; Vogel, Robert; Platt, Mark

    2016-02-02

    Resistive pulse sensors, RPS, are allowing the transport mechanism of molecules, proteins and even nanoparticles to be characterized as they traverse pores. Previous work using RPS has shown that the size, concentration and zeta potential of the analyte can be measured. Here we use tunable resistive pulse sensing (TRPS) which utilizes a tunable pore to monitor the translocation times of nanoparticles with DNA modified surfaces. We start by demonstrating that the translocation times of particles can be used to infer the zeta potential of known standards and then apply the method to measure the change in zeta potential of DNA modified particles. By measuring the translocation times of DNA modified nanoparticles as a function of packing density, length, structure, and hybridization time, we observe a clear difference in zeta potential using both mean values and population distributions as a function of the DNA structure. We demonstrate the ability to resolve the signals for ssDNA, dsDNA, small changes in base length for nucleotides between 15 and 40 bases long, and even the discrimination between partial and fully complementary target sequences. Such a method has potential and applications in sensors for the monitoring of nanoparticles in both medical and environmental samples.

  19. Fracture resistance of three-unit zirconia fixed partial denture with modified framework.

    PubMed

    Partiyan, Arthur; Osman, Essam; Rayyan, Mohammad M; Aboushelib, Moustafa; Ibrahim, Ahmed; Jimbo, Ryo

    2017-01-01

    Obtaining ideal prosthetic framework design is at times hindered by anatomical limitations in the posterior region that might increase the risk for zirconia restoration fracture. Modification such as increasing the bulk thickness especially in the connector region could result in strengthening the zirconia framework. Three-unit zirconia fixed partial dentures replacing mandibular molars were fabricated using the following two techniques: CAD/CAM technology and manual copy milling. Modified framework with unveneered full thickness connectors were designed and fabricated with the aforementioned methods. Conventional frameworks (0.5 mm thick with rounded 3 mm connectors) served as control (N = 20). After cementation on epoxy dies, the frameworks were loaded to fracture in a universal testing machine. Fractured surfaces were prepared for examination using scanning electron microscopy. Statistical analysis revealed significant differences in fracture resistance between conventional and modified framework design for both fabrication techniques tested. SEM examination indicated that critical crack originated at the tensile surface of the connectors for conventional frameworks. The critical crack for modified frameworks occurred on the axial wall of the abutments. The modification of the zirconia framework design presented significant improvement of the fracture resistance compared to the conventional design.

  20. Age hardening and creep resistance of cast Al–Cu alloy modified by praseodymium

    SciTech Connect

    Bai, Zhihao; Qiu, Feng; Wu, Xiaoxue; Liu, Yingying; Jiang, Qichuan

    2013-12-15

    The effects of praseodymium on age hardening behavior and creep resistance of cast Al–Cu alloy were investigated. The results indicated that praseodymium facilitated the formation of the θ′ precipitates during the age process and improved the hardness of the Al–Cu alloy. Besides, praseodymium resulted in the formation of the Al{sub 11}Pr{sub 3} phase in the grain boundaries and among the dendrites of the modified alloy. Because of the good thermal stability of Al{sub 11}Pr{sub 3} phase, it inhibits grain boundary migration and dislocation movement during the creep process, which contributes to the improvement in the creep resistance of the modified alloy at elevated temperatures. - Highlights: • Pr addition enhances the hardness and creep resistance of the Al–Cu alloy. • Pr addition facilitates the formation of the θ′ precipitates. • Pr addition results in the formation of the Al11Pr3 phase in the Al–Cu alloy.

  1. Evidence of field-evolved resistance of Spodoptera frugiperda to Bt corn expressing Cry1F in Brazil that is still sensitive to modified Bt toxins.

    PubMed

    Monnerat, Rose; Martins, Erica; Macedo, Cristina; Queiroz, Paulo; Praça, Lilian; Soares, Carlos Marcelo; Moreira, Helio; Grisi, Isabella; Silva, Joseane; Soberon, Mario; Bravo, Alejandra

    2015-01-01

    Brazil ranked second only to the United States in hectares planted to genetically modified crops in 2013. Recently corn producers in the Cerrado region reported that the control of Spodoptera frugiperda with Bt corn expressing Cry1Fa has decreased, forcing them to use chemicals to reduce the damage caused by this insect pest. A colony of S. frugiperda was established from individuals collected in 2013 from Cry1Fa corn plants (SfBt) in Brazil and shown to have at least more than ten-fold higher resistance levels compared with a susceptible colony (Sflab). Laboratory assays on corn leaves showed that in contrast to SfLab population, the SfBt larvae were able to survive by feeding on Cry1Fa corn leaves. The SfBt population was maintained without selection for eight generations and shown to maintain high levels of resistance to Cry1Fa toxin. SfBt showed higher cross-resistance to Cry1Aa than to Cry1Ab or Cry1Ac toxins. As previously reported, Cry1A toxins competed the binding of Cry1Fa to brush border membrane vesicles (BBMV) from SfLab insects, explaining cross-resistance to Cry1A toxins. In contrast Cry2A toxins did not compete Cry1Fa binding to SfLab-BBMV and no cross-resistance to Cry2A was observed, although Cry2A toxins show low toxicity to S. frugiperda. Bioassays with Cry1AbMod and Cry1AcMod show that they are highly active against both the SfLab and the SfBt populations. The bioassay data reported here show that insects collected from Cry1Fa corn in the Cerrado region were resistant to Cry1Fa suggesting that resistance contributed to field failures of Cry1Fa corn to control S. frugiperda.

  2. Virus-induced gene silencing using a modified betasatellite: a potential candidate for functional genomics of crops.

    PubMed

    Kumar, Jitendra; Gunapati, Samatha; Kumar, Jitesh; Kumari, Anita; Kumar, Abhinav; Tuli, Rakesh; Singh, Sudhir P

    2014-08-01

    Betasatellites are geminivirus-associated single-stranded DNA molecules that play an important role in symptom modulation. A VIGS vector was developed by modifying cotton leaf curl Multan betasatellite (CLCuMB). CLCuMB DNA was modified by replacing the βC1 gene with a multiple cloning site. The silencing ability of the modified CLCuMB was investigated by cloning a fragment of a host gene (Su) or a reporter transgene (uidA) into the modified CLCuMB and co-agroinoculation with cotton leaf curl Multan virus, cotton leaf curl Kokhran virus, and ageratum enation virus, separately. The inoculated Nicotiana tabacum, N. benthamiana, Solanum lycopersicum, Arabidopsis thaliana and Gossypium hirsutum plants showed efficient silencing of the cognate genes.

  3. Importance of unusually modified lipid A in Sinorhizobium stress resistance and legume symbiosis.

    PubMed

    Ferguson, Gail P; Datta, Anup; Carlson, Russ W; Walker, Graham C

    2005-04-01

    Sinorhizobium meliloti, a legume symbiont and Brucella abortus, a phylogenetically related mammalian pathogen, both require their BacA proteins to establish chronic intracellular infections in their respective hosts. The lipid A molecules of S. meliloti and B. abortus are unusually modified with a very-long-chain fatty acid (VLCFA; C > or = 28) and we discovered that BacA is involved in this unusual modification. This observation raised the possibility that the unusual lipid A modification could be crucial for the chronic infection of both S. meliloti and B. abortus. We investigated this by constructing and characterizing S. meliloti mutants in the lpxXL and acpXL genes, which encode an acyl transferase and acyl carrier protein directly involved in the biosynthesis of VLCFA-modified lipid A. Our analysis revealed that the unusually modified lipid A is important, but not crucial, for S. meliloti chronic infection and that BacA must have an additional function, which in combination with its observed effect on the lipid A in the free-living form of S. meliloti, is essential for the chronic infection. Additionally, we discovered that in the absence of VLCFAs, S. meliloti produces novel pentaacylated lipid A species, modified with unhydroxylated fatty acids, which are important for stress resistance.

  4. Functionality of Varroa-resistant honey bees (Hymenoptera: Apidae) when used in migratory beekeeping for crop pollination.

    PubMed

    Danka, Robert G; De Guzman, Lilia I; Rinderer, Thomas E; Sylvester, H Allen; Wagener, Christine M; Bourgeois, A Lelania; Harris, Jeffrey W; Villa, José D

    2012-04-01

    Two types of honey bees, Apis mellifera L. (Hymenoptera: Apidae), bred for resistance to Varroa destructor Anderson & Trueman were evaluated for performance when used in migratory crop pollination. Colonies of Russian honey bees (RHB) and outcrossed bees with Varroa-sensitive hygiene (VSH) were managed without miticide treatments and compared with colonies of Italian honey bees that served as controls. Control colonies were managed as groups which either were treated twice each year against V. destructor (CT) or kept untreated (CU). Totals of 240 and 247 colonies were established initially for trials in 2008 and 2009, respectively. RHB and VSH colonies generally had adult and brood populations similar to those of the standard CT group regarding pollination requirements. For pollination of almonds [Prunus dulcis (Mill.) D.A.Webb] in February, percentages of colonies meeting the required six or more frames of adult bees were 57% (VSH), 56% (CT), 39% (RHB), and 34% (CU). RHB are known to have small colonies in early spring, but this can be overcome with appropriate feeding. For later pollination requirements in May to July, 94-100% of colonies in the four groups met pollination size requirements for apples (Malus domestica Borkh.), cranberries (Vaccinium macrocarpon Aiton), and lowbush blueberries (Vaccinium angustifolium Aiton). Infestations with V. destructor usually were lowest in CT colonies and tended to be lower in VSH colonies than in RHB and CU colonies. This study demonstrates that bees with the VSH trait and pure RHB offer alternatives for beekeepers to use for commercial crop pollination while reducing reliance on miticides. The high frequency of queen loss (only approximately one fourth of original queens survived each year) suggests that frequent requeening is necessary to maintain desired genetics.

  5. Impact of long-term cropping of glyphosate-resistant transgenic soybean [Glycine max (L.) Merr.] on soil microbiome.

    PubMed

    Babujia, Letícia Carlos; Silva, Adriana Pereira; Nakatani, André Shigueyoshi; Cantão, Mauricio Egidio; Vasconcelos, Ana Tereza Ribeiro; Visentainer, Jesuí Vergilio; Hungria, Mariangela

    2016-08-01

    The transgenic soybean [Glycine max (L.) Merrill] occupies about 80 % of the global area cropped with this legume, the majority comprising the glyphosate-resistant trait (Roundup Ready(®), GR or RR). However, concerns about possible impacts of transgenic crops on soil microbial communities are often raised. We investigated soil chemical, physical and microbiological properties, and grain yields in long-term field trials involving conventional and nearly isogenic RR transgenic genotypes. The trials were performed at two locations in Brazil, with different edaphoclimatic conditions. Large differences in physical, chemical and classic microbiological parameters (microbial biomass of C and N, basal respiration), as well as in grain production were observed between the sites. Some phyla (Proteobacteria, Actinobacteria, Acidobacteria), classes (Alphaproteobacteria, Actinomycetales, Solibacteres) and orders (Rhizobiales, Burkholderiales, Myxococcales, Pseudomonadales), as well as some functional subsystems (clustering-based subsystems, carbohydrates, amino acids and protein metabolism) were, in general, abundant in all treatments. However, bioindicators related to superior soil fertility and physical properties at Londrina were identified, among them a higher ratio of Proteobacteria:Acidobacteria. Regarding the transgene, the metagenomics showed differences in microbial taxonomic and functional abundances, but lower in magnitude than differences observed between the sites. Besides the site-specific differences, Proteobacteria, Firmicutes and Chlorophyta were higher in the transgenic treatment, as well as sequences related to protein metabolism, cell division and cycle. Although confirming effects of the transgenic trait on soil microbiome, no differences were recorded in grain yields, probably due to the buffering capacity associated with the high taxonomic and functional microbial diversity observed in all treatments.

  6. Evaluation of spectrophotometric and HPLC methods for shikimic acid determination in plants: models in glyphosate-resistant and -susceptible crops.

    PubMed

    Zelaya, Ian A; Anderson, Jennifer A H; Owen, Micheal D K; Landes, Reid D

    2011-03-23

    Endogenous shikimic acid determinations are routinely used to assess the efficacy of glyphosate in plants. Numerous analytical methods exist in the public domain for the detection of shikimic acid, yet the most commonly cited comprise spectrophotometric and high-pressure liquid chromatography (HPLC) methods. This paper compares an HPLC and two spectrophotometric methods (Spec 1 and Spec 2) and assesses the effectiveness in the detection of shikimic acid in the tissues of glyphosate-treated plants. Furthermore, the study evaluates the versatility of two acid-based shikimic acid extraction methods and assesses the longevity of plant extract samples under different storage conditions. Finally, Spec 1 and Spec 2 are further characterized with respect to (1) the capacity to discern between shikimic acid and chemically related alicyclic hydroxy acids, (2) the stability of the chromophore (t1/2), (3) the detection limits, and (4) the cost and simplicity of undertaking the analytical procedure. Overall, spectrophotometric methods were more cost-effective and simpler to execute yet provided a narrower detection limit compared to HPLC. All three methods were specific to shikimic acid and detected the compound in the tissues of glyphosate-susceptible crops, increasing exponentially in concentration within 24 h of glyphosate application and plateauing at approximately 72 h. Spec 1 estimated more shikimic acid in identical plant extract samples compared to Spec 2 and, likewise, HPLC detection was more effective than spectrophotometric determinations. Given the unprecedented global adoption of glyphosate-resistant crops and concomitant use of glyphosate, an effective and accurate assessment of glyphosate efficacy is important. Endogenous shikimic acid determinations are instrumental in corroborating the efficacy of glyphosate and therefore have numerous applications in herbicide research and related areas of science as well as resolving many commercial issues as a consequence of

  7. Effect of crop plants on fitness costs associated with resistance to Bacillus thuringiensis toxins Cry1Ac and Cry2Ab in cabbage loopers.

    PubMed

    Wang, Ran; Tetreau, Guillaume; Wang, Ping

    2016-02-12

    Fitness costs associated with resistance to Bacillus thuringiensis (Bt) toxins critically impact the development of resistance in insect populations. In this study, the fitness costs in Trichoplusia ni strains associated with two genetically independent resistance mechanisms to Bt toxins Cry1Ac and Cry2Ab, individually and in combination, on four crop plants (cabbage, cotton, tobacco and tomato) were analyzed, in comparison with their near-isogenic susceptible strain. The net reproductive rate (R0) and intrinsic rate of increase (r) of the T. ni strains, regardless of their resistance traits, were strongly affected by the host plants. The ABCC2 gene-linked mechanism of Cry1Ac resistance was associated with relatively low fitness costs, while the Cry2Ab resistance mechanism was associated with higher fitness costs. The fitness costs in the presence of both resistance mechanisms in T. ni appeared to be non-additive. The relative fitness of Bt-resistant T. ni depended on the specific resistance mechanisms as well as host plants. In addition to difference in survivorship and fecundity, an asynchrony of adult emergence was observed among T. ni with different resistance mechanisms and on different host plants. Therefore, mechanisms of resistance and host plants available in the field are both important factors affecting development of Bt resistance in insects.

  8. Effect of crop plants on fitness costs associated with resistance to Bacillus thuringiensis toxins Cry1Ac and Cry2Ab in cabbage loopers

    PubMed Central

    Wang, Ran; Tetreau, Guillaume; Wang, Ping

    2016-01-01

    Fitness costs associated with resistance to Bacillus thuringiensis (Bt) toxins critically impact the development of resistance in insect populations. In this study, the fitness costs in Trichoplusia ni strains associated with two genetically independent resistance mechanisms to Bt toxins Cry1Ac and Cry2Ab, individually and in combination, on four crop plants (cabbage, cotton, tobacco and tomato) were analyzed, in comparison with their near-isogenic susceptible strain. The net reproductive rate (R0) and intrinsic rate of increase (r) of the T. ni strains, regardless of their resistance traits, were strongly affected by the host plants. The ABCC2 gene-linked mechanism of Cry1Ac resistance was associated with relatively low fitness costs, while the Cry2Ab resistance mechanism was associated with higher fitness costs. The fitness costs in the presence of both resistance mechanisms in T. ni appeared to be non-additive. The relative fitness of Bt-resistant T. ni depended on the specific resistance mechanisms as well as host plants. In addition to difference in survivorship and fecundity, an asynchrony of adult emergence was observed among T. ni with different resistance mechanisms and on different host plants. Therefore, mechanisms of resistance and host plants available in the field are both important factors affecting development of Bt resistance in insects. PMID:26868936

  9. Annual Medicago: From a Model Crop Challenged by a Spectrum of Necrotrophic Pathogens to a Model Plant to Explore the Nature of Disease Resistance

    PubMed Central

    TIVOLI, B.; BARANGER, A.; SIVASITHAMPARAM, K.; BARBETTI, M. J.

    2006-01-01

    • Background Annual Medicago spp., including M. truncatula, play an important agronomic role in dryland farming regions of the world where they are often an integral component of cropping systems, particularly in regions with a Mediterranean or Mediterranean-type climate where they grow as winter annuals that provide both nitrogen and disease breaks for rotational crops. Necrotrophic foliar and soil-borne pathogens dominate these regions and challenge the productivity of annual Medicago and crop legume species. • Scope This review outlines some of the major and/or widespread diseases these necrotrophic pathogens cause on Medicago spp. It then explores the potential for using the spectrum of necrotrophic pathogen–host interactions, with annual Medicago as the host plant, to better understand and model pathosystems within the diseases caused by nectrotrophic pathogens across forage and grain legume crops. • Conclusions Host resistance clearly offers the best strategy for cost-effective, long-term control of necrotrophic foliar and soil-borne pathogens, particularly as useful resistance to a number of these diseases has been identified. Recently and initially, the annual M. truncatula has emerged as a more appropriate and agronomically relevant substitute to Arabidopsis thaliana as a model plant for legumes, and is proving an excellent model to understand the mechanisms of resistance both to individual pathogens and more generally to most forage and grain legume necrotrophic pathogens. PMID:16803846

  10. Modified Bacillus thuringiensis toxins and a hybrid B. thuringiensis strain counter greenhouse-selected resistance in Trichoplusia ni.

    PubMed

    Franklin, Michelle T; Nieman, Christal L; Janmaat, Alida F; Soberón, Mario; Bravo, Alejandra; Tabashnik, Bruce E; Myers, Judith H

    2009-09-01

    Resistance of greenhouse-selected strains of the cabbage looper, Trichoplusia ni, to Bacillus thuringiensis subsp. kurstaki was countered by a hybrid strain of B. thuringiensis and genetically modified toxins Cry1AbMod and Cry1AcMod, which lack helix alpha-1. Resistance to Cry1AbMod and Cry1AcMod was >100-fold less than resistance to native toxins Cry1Ab and Cry1Ac.

  11. The heat resistance of a polyurethane coating filled with modified nano-CaCO3

    NASA Astrophysics Data System (ADS)

    Li, Bin; Li, Song-Mei; Liu, Jian-Hua; Yu, Mei

    2014-10-01

    The modification of polyurethane coating by adding surface-modified CaCO3 nanoparticles (nano-CaCO3) was investigated in this paper. To improve interfacial interaction between the nano-CaCO3 and the polyurethane (PU) matrix, a silane coupling agent (KH560) was used to modify the nano-CaCO3. The grafting of KH560 on the nano-CaCO3 surfaces was characterized by the TEM, FTIR and TGA techniques. The modification of the nano-CaCO3 surfaces with KH560 was demonstrated to improve the dispersity of nano-CaCO3. FTIR, SEM and AFM were used to characterize the polyurethane coating. The FTIR spectrum indicated that the modification of nano-CaCO3 does not influence the chemical structure of the PU matrix. The roughness and gloss of the nanocomposite coatings containing various amount of nano-CaCO3 were evaluated using a roughness tester and a brightness meter. The heat resistance of the polyurethane coating containing various amounts of nano-CaCO3 was evaluated using the TGA technique. The results revealed that nano-CaCO3 treatment with KH560 improves the nanoparticle dispersion and heat-resistance of polyurethane coating.

  12. Thermal-fatigue and oxidation resistance of cobalt-modified Udimet 700 alloy

    NASA Technical Reports Server (NTRS)

    Bizon, P. T.; Barrow, B. J.

    1986-01-01

    Comparative thermal-fatigue and oxidation resistances of cobalt-modified wrought Udimet 700 alloy (obtained by reducing the cobalt level by direct substitution of nickel) were determined from fluidized-bed tests. Bed temperatures were 1010 and 288 C (1850 and 550 C) for the first 5500 symmetrical 6-min cycles. From cycle 5501 to the 14000-cycle limit of testing, the heating bed temperature was increased to 1050 C (1922 F). Cobalt levels between 0 and 17 wt% were studied in both the bare and NiCrAlY overlay coated conditions. A cobalt level of about 8 wt% gave the best thermal-fatigue life. The conventional alloy specification is for 18.5% cobalt, and hence, a factor of 2 in savings of cobalt could be achieved by using the modified alloy. After 13500 cycles, all bare cobalt-modified alloys lost 10 to 13 percent of their initial weight. Application of the NiCrAlY overlay coating resulted in weight losses of 1/20 to 1/100 of that of the corresponding bare alloy.

  13. Engineering RNA interference-based resistance to dengue virus type 2 in genetically modified Aedes aegypti.

    PubMed

    Franz, Alexander W E; Sanchez-Vargas, Irma; Adelman, Zach N; Blair, Carol D; Beaty, Barry J; James, Anthony A; Olson, Ken E

    2006-03-14

    Mosquitoes (Aedes aegypti) were genetically modified to exhibit impaired vector competence for dengue type 2 viruses (DENV-2). We exploited the natural antiviral RNA interference (RNAi) pathway in the mosquito midgut by constructing an effector gene that expresses an inverted-repeat (IR) RNA derived from the premembrane protein coding region of the DENV-2 RNA genome. The A. aegypti carboxypeptidase A promoter was used to express the IR RNA in midgut epithelial cells after ingestion of a bloodmeal. The promoter and effector gene were inserted into the genome of a white-eye Puerto Rico Rexville D (Higgs' white eye) strain by using the nonautonomous mariner MosI transformation system. A transgenic family, Carb77, expressed IR RNA in the midgut after a bloodmeal. Carb77 mosquitoes ingesting an artificial bloodmeal containing DENV-2 exhibited marked reduction of viral envelope antigen in midguts and salivary glands after infection. DENV-2 titration of individual mosquitoes showed that most Carb77 mosquitoes poorly supported virus replication. Transmission in vitro of virus from the Carb77 line was significantly diminished when compared to control mosquitoes. The presence of DENV-2-derived siRNAs in RNA extracts from midguts of Carb77 and the loss of the resistance phenotype when the RNAi pathway was interrupted proved that DENV-2 resistance was caused by a RNAi response. Engineering of transgenic A. aegypti that show a high level of resistance against DENV-2 provides a powerful tool for developing population replacement strategies to control transmission of dengue viruses.

  14. Electrochemical sensor for multiplex screening of genetically modified DNA: identification of biotech crops by logic-based biomolecular analysis.

    PubMed

    Liao, Wei-Ching; Chuang, Min-Chieh; Ho, Ja-An Annie

    2013-12-15

    Genetically modified (GM) technique, one of the modern biomolecular engineering technologies, has been deemed as profitable strategy to fight against global starvation. Yet rapid and reliable analytical method is deficient to evaluate the quality and potential risk of such resulting GM products. We herein present a biomolecular analytical system constructed with distinct biochemical activities to expedite the computational detection of genetically modified organisms (GMOs). The computational mechanism provides an alternative to the complex procedures commonly involved in the screening of GMOs. Given that the bioanalytical system is capable of processing promoter, coding and species genes, affirmative interpretations succeed to identify specified GM event in terms of both electrochemical and optical fashions. The biomolecular computational assay exhibits detection capability of genetically modified DNA below sub-nanomolar level and is found interference-free by abundant coexistence of non-GM DNA. This bioanalytical system, furthermore, sophisticates in array fashion operating multiplex screening against variable GM events. Such a biomolecular computational assay and biosensor holds great promise for rapid, cost-effective, and high-fidelity screening of GMO.

  15. Safely Coupling Livestock and Crop Production Systems: How Rapidly Do Antibiotic Resistance Genes Dissipate in Soil following a Commercial Application of Swine or Dairy Manure?

    PubMed Central

    Marti, Romain; Tien, Yuan-Ching; Murray, Roger; Scott, Andrew; Sabourin, Lyne

    2014-01-01

    Animal manures recycled onto crop production land carry antibiotic-resistant bacteria. The present study evaluated the fate in soil of selected genes associated with antibiotic resistance or genetic mobility in field plots cropped to vegetables and managed according to normal farming practice. Referenced to unmanured soil, fertilization with swine or dairy manure increased the relative abundance of the gene targets sul1, erm(B), str(B), int1, and IncW repA. Following manure application in the spring of 2012, gene copy number decayed exponentially, reaching background levels by the fall of 2012. In contrast, gene copy number following manure application in the fall of 2012 or spring of 2013 increased significantly in the weeks following application and then declined. In both cases, the relative abundance of gene copy numbers had not returned to background levels by the fall of 2013. Overall, these results suggest that under conditions characteristic of agriculture in a humid continental climate, a 1-year period following a commercial application of raw manure is sufficient to ensure that an additional soil burden of antibiotic resistance genes approaches background. The relative abundance of several gene targets exceeded background during the growing season following a spring application or an application done the previous fall. Results from the present study reinforce the advisability of treating manure prior to use in crop production systems. PMID:24632259

  16. Safely coupling livestock and crop production systems: how rapidly do antibiotic resistance genes dissipate in soil following a commercial application of swine or dairy manure?

    PubMed

    Marti, Romain; Tien, Yuan-Ching; Murray, Roger; Scott, Andrew; Sabourin, Lyne; Topp, Edward

    2014-05-01

    Animal manures recycled onto crop production land carry antibiotic-resistant bacteria. The present study evaluated the fate in soil of selected genes associated with antibiotic resistance or genetic mobility in field plots cropped to vegetables and managed according to normal farming practice. Referenced to unmanured soil, fertilization with swine or dairy manure increased the relative abundance of the gene targets sul1, erm(B), str(B), int1, and IncW repA. Following manure application in the spring of 2012, gene copy number decayed exponentially, reaching background levels by the fall of 2012. In contrast, gene copy number following manure application in the fall of 2012 or spring of 2013 increased significantly in the weeks following application and then declined. In both cases, the relative abundance of gene copy numbers had not returned to background levels by the fall of 2013. Overall, these results suggest that under conditions characteristic of agriculture in a humid continental climate, a 1-year period following a commercial application of raw manure is sufficient to ensure that an additional soil burden of antibiotic resistance genes approaches background. The relative abundance of several gene targets exceeded background during the growing season following a spring application or an application done the previous fall. Results from the present study reinforce the advisability of treating manure prior to use in crop production systems.

  17. Detection of genetically modified crops using multiplex asymmetric polymerase chain reaction and asymmetric hyperbranched rolling circle amplification coupled with reverse dot blot.

    PubMed

    Wang, Xiumin; Teng, Da; Guan, Qingfeng; Tian, Fang; Wang, Jianhua

    2015-04-15

    To meet the ever-increasing demand for detection of genetically modified crops (GMCs), low-cost, high-throughput and high-accuracy detection assays are needed. The new multiplex asymmetric polymerase chain reaction and asymmetric hyper-branched rolling circle amplification coupled with reverse dot blot (RDB) systems were developed to detect GMCs. Thirteen oligonucleotide probes were designed to identify endogenous targets (Lec1, Hmg and Sad1), event-specific targets (RRS-5C, RRS-3C, Bt176-3C and MON810-3C), screening targets (35S promoter and NOS terminator), and control targets (18S and PLX). Optimised conditions were as follows: tailed hybridization probes (1-2 pmol/l) were immobilized on a membrane by baking for 2h, and a 10:1 ratio of forward to reverse primers was used. The detection limits were 0.1 μg/l of 2% RRS and 0.5 ng/l of DNA from genetically modified (GM) soybean. These results indicate that the RDB assay could be used to detect multiplex target genes of GMCs rapidly and inexpensively.

  18. Chromium-modified a-C films with advanced structural, mechanical and corrosive-resistant characteristics

    NASA Astrophysics Data System (ADS)

    Ming, Miao Yi; Jiang, Xiaohong; Piliptsou, D. G.; Zhuang, Yuzhao; Rogachev, A. V.; Rudenkov, A. S.; Balmakou, A.

    2016-08-01

    To improve structural, mechanical and chemical properties of diamond-like carbon films, we developed amorphous carbon chromium-modified composite films fabricated by means of cathode magnetic filtered arc deposition. The properties were analyzed by Raman spectroscopy, X-ray photoelectron spectroscopy and atomic force microscopy for the purpose of the structure characterization, elemental analysis and topology examination. Moreover, we also assessed residual stress, the coefficient of friction, hardness, the elastic modulus and corrosion parameters through X-ray double-crystal surface profilometry, tribo-testing, nanoindenter-testing, as well as contact angle measurements and potentiodynamic polarization analysis. As a result of a comparative analysis, we revealed a substantial improvement in the characteristics of developed composite films in comparison with amorphous carbon films. For example, Cr-modification is resulted, in greater integrated performance, toughness and corrosion resistance; the residual stress was reduced substantially.

  19. Chemically modified Si(111) surfaces simultaneously demonstrating hydrophilicity, resistance against oxidation, and low trap state densities

    NASA Astrophysics Data System (ADS)

    Brown, Elizabeth S.; Hlynchuk, Sofiya; Maldonado, Stephen

    2016-03-01

    Chemically modified Si(111) surfaces have been prepared through a series of wet chemical surface treatments that simultaneously show resistance towards surface oxidation, selective reactivity towards chemical reagents, and areal defect densities comparable to unannealed thermal oxides. Specifically, grazing angle attenuated total reflectance infrared and X-ray photoelectron (XP) spectroscopies were used to characterize allyl-, 3,4-methylenedioxybenzene-, or 4-[bis(trimethylsilyl)amino]phenyl-terminated surfaces and the subsequently hydroxylated surfaces. Hydroxylated surfaces were confirmed through reaction with 4-(trifluoromethyl)benzyl bromide and quantified by XP spectroscopy. Contact angle measurements indicated all surfaces remained hydrophilic, even after secondary backfilling with CH3sbnd groups. Surface recombination velocity measurements by way of microwave photoconductivity transients showed the relative defect-character of as-prepared and aged surfaces. The relative merits for each investigated surface type are discussed.

  20. Distribution of genes encoding aminoglycoside-modifying enzymes among clinical isolates of methicillin-resistant staphylococci.

    PubMed

    Perumal, N; Murugesan, S; Krishnan, P

    2016-01-01

    The objective of this study was to determine the distribution of genes encoding aminoglycoside-modifying enzymes (AMEs) and staphylococcal cassette chromosome mec (SCCmec) elements among clinical isolates of methicillin-resistant staphylococci (MRS). Antibiotic susceptibility test was done using Kirby-Bauer disk diffusion method. The presence of SCCmec types and AME genes, namely, aac (6')-Ie-aph (2''), aph (3')-IIIa and ant (4')-Ia was determined using two different multiplex polymerase chain reaction. The most encountered AME genes were aac (6')-Ie-aph (2'') (55.4%) followed by aph (3')-IIIa (32.3%) and ant (4')-Ia gene (9%). SCCmec type I (34%) was predominant in this study. In conclusion, the aac (6')-Ie-aph (2'') was the most common AME gene and SCCmec type I was most predominant among the MRS isolates.

  1. Botrytis pseudocinerea Is a Significant Pathogen of Several Crop Plants but Susceptible to Displacement by Fungicide-Resistant B. cinerea Strains

    PubMed Central

    Plesken, Cecilia; Weber, Roland W. S.; Rupp, Sabrina; Leroch, Michaela

    2015-01-01

    Botrytis cinerea is one of the most important pathogens worldwide, causing gray mold on a large variety of crops. Botrytis pseudocinerea has been found previously to occur together with B. cinerea in low abundance in vineyards and strawberry fields. Here, we report B. pseudocinerea to be common and sometimes dominant over B. cinerea on several fruit and vegetable crops in Germany. On apples with calyx end rot and on oilseed rape, it was the major gray mold species. Abundance of B. pseudocinerea was often negatively correlated with fungicide treatments. On cultivated strawberries, it was frequently found in spring but was largely displaced by B. cinerea following fungicide applications. Whereas B. cinerea strains with multiple-fungicide resistance were common in these fields, B. pseudocinerea almost never developed resistance to any fungicide even though resistance mutations occurred at similar frequencies in both species under laboratory conditions. The absence of resistance to quinone outside inhibitors in B. pseudocinerea was correlated with an intron in cytB preventing the major G143A resistance mutation. Our work indicates that B. pseudocinerea has a wide host range similar to that of B. cinerea and that it can become an important gray mold pathogen on cultivated plants. PMID:26231644

  2. Wing shape and size of the western corn rootworm (Coleoptera: Chrysomelidae) is related to sex and resistance to soybean-maize crop rotation.

    PubMed

    Mikac, K M; Douglas, J; Spencer, J L

    2013-08-01

    The western corn rootworm, Diabrotica virgifera virgifera LeConte, is a major pest of maize in the United States and more recently, Europe. Understanding the dispersal dynamics of this species will provide crucial information for its management. This study used geometric morphometric analysis of hind wing venation based on 13 landmarks in 223 specimens from nine locations in Illinois, Nebraska, Iowa, and Missouri, to assess whether wing shape and size differed between rotated and continuously grown maize where crop rotation-resistant and susceptible individuals are found, respectively. Before assessing differences between rotation-resistant and susceptible individuals, sexual dimorphism was investigated. No significant difference in wing (centroid) size was found between males and females; however, females had significantly different shaped (more elongated) wings compared with males. Wing shape and (centroid) size were significantly larger among individuals from rotated maize where crop-rotation resistance was reported; however, cross-validation of these results revealed that collection site resistance status was an only better than average predictor of shape in males and females. This study provides preliminary evidence of wing shape and size differences in D. v. virgifera from rotated versus continuous maize. Further study is needed to confirm whether wing shape and size can be used to track the movement of rotation-resistant individuals and populations as a means to better inform management strategies.

  3. Ethical issues in field trials of genetically modified disease-resistant mosquitoes.

    PubMed

    Resnik, David B

    2014-04-01

    Mosquito-borne diseases take a tremendous toll on human populations, especially in developing nations. In the last decade, scientists have developed mosquitoes that have been genetically modified to prevent transmission of mosquito-borne diseases, and field trials have been conducted. Some mosquitoes have been rendered infertile, some have been equipped with a vaccine they transmit to humans, and some have been designed to resist diseases. This article focuses on ethical issues raised by field trials of disease-resistant, genetically modified mosquitoes. Some of these issues include: protecting the public and the environment from harm, balancing benefits and risks, collaborating with the local community, avoiding exploitation, and safeguarding the rights and welfare of research subjects. One of the most difficult problems involves protecting the welfare of community members who will be impacted by the release of mosquitoes but who are not enrolled in the study as research subjects. To address this concern, field trials should take place only when the targeted disease is a significant public health problem in an isolated area, the benefits of the trial for the community are likely to outweigh the risks, community leaders approve of the trial, and there are measures in place to protect the welfare of un-enrolled community members, such as informing the community about the study and offering free treatment to people who contract mosquito-borne diseases. Since the justification of any field trial depends on a careful examination of the scientific and ethical issues, proposed studies should be evaluated on a case-by-case basis.

  4. ETHICAL ISSUES IN FIELD TRIALS OF GENETICALLY MODIFIED DISEASE-RESISTANT MOSQUITOES

    PubMed Central

    RESNIK, DAVID B.

    2012-01-01

    Mosquito-borne diseases take a tremendous toll on human populations, especially in developing nations. In the last decade, scientists have developed mosquitoes that have been genetically modified to prevent transmission of mosquito-borne diseases, and field trials have been conducted. Some mosquitoes have been rendered infertile, some have been equipped with a vaccine they transmit to humans, and some have been designed to resist diseases. This article focuses on ethical issues raised by field trials of disease-resistant, genetically modified mosquitoes. Some of these issues include: protecting the public and the environment from harm, balancing benefits and risks, collaborating with the local community, avoiding exploitation, and safeguarding the rights and welfare of research subjects. One of the most difficult problems involves protecting the welfare of community members who will be impacted by the release of mosquitoes but who are not enrolled in the study as research subjects. To address this concern, field trials should take place only when the targeted disease is a significant public health problem in an isolated area, the benefits of the trial for the community are likely to outweigh the risks, community leaders approve of the trial, and there are measures in place to protect the welfare of un-enrolled community members, such as informing the community about the study and offering free treatment to people who contract mosquito-borne diseases. Since the justification of any field trial depends on a careful examination of the scientific and ethical issues, proposed studies should be evaluated on a case-by-case basis. PMID:23279283

  5. RNA-seq pinpoints a Xanthomonas TAL-effector activated resistance gene in a large-crop genome.

    PubMed

    Strauss, Tina; van Poecke, Remco M P; Strauss, Annett; Römer, Patrick; Minsavage, Gerald V; Singh, Sylvia; Wolf, Christina; Strauss, Axel; Kim, Seungill; Lee, Hyun-Ah; Yeom, Seon-In; Parniske, Martin; Stall, Robert E; Jones, Jeffrey B; Choi, Doil; Prins, Marcel; Lahaye, Thomas

    2012-11-20

    Transcription activator-like effector (TALE) proteins of the plant pathogenic bacterial genus Xanthomonas bind to and transcriptionally activate host susceptibility genes, promoting disease. Plant immune systems have taken advantage of this mechanism by evolving TALE binding sites upstream of resistance (R) genes. For example, the pepper Bs3 and rice Xa27 genes are hypersensitive reaction plant R genes that are transcriptionally activated by corresponding TALEs. Both R genes have a hallmark expression pattern in which their transcripts are detectable only in the presence and not the absence of the corresponding TALE. By transcriptome profiling using next-generation sequencing (RNA-seq), we tested whether we could avoid laborious positional cloning for the isolation of TALE-induced R genes. In a proof-of-principle experiment, RNA-seq was used to identify a candidate for Bs4C, an R gene from pepper that mediates recognition of the Xanthomonas TALE protein AvrBs4. We identified one major Bs4C candidate transcript by RNA-seq that was expressed exclusively in the presence of AvrBs4. Complementation studies confirmed that the candidate corresponds to the Bs4C gene and that an AvrBs4 binding site in the Bs4C promoter directs its transcriptional activation. Comparison of Bs4C with a nonfunctional allele that is unable to recognize AvrBs4 revealed a 2-bp polymorphism within the TALE binding site of the Bs4C promoter. Bs4C encodes a structurally unique R protein and Bs4C-like genes that are present in many solanaceous genomes seem to be as tightly regulated as pepper Bs4C. These findings demonstrate that TALE-specific R genes can be cloned from large-genome crops with a highly efficient RNA-seq approach.

  6. The fretting corrosion resistance of PVD surface-modified orthopedic implant alloys.

    PubMed

    Hendry, J A; Pilliar, R M

    2001-01-01

    The objective of this study was to evaluate the fretting corrosion resistance of both modified and unmodified Ti6Al4V flats fretted against CoCr-alloy spheres in a buffered Hank's solution at 37 degrees C using an original fretting apparatus. A physical vapor deposition (PVD) cathodic arc evaporation technique was used to deposit 3-4 microm thick titanium nitride (TiN), zirconium nitride (ZrN), or amorphous carbon (AC) coatings onto the Ti6Al4V substrates. The fretting behavior of the nitride films (TiN and ZrN) was characterized by the absence of surface damage and the deposition of a Cr-rich oxide transferred from the CoCr-alloy spheres to the modified surfaces. This oxide led to a slight increase in surface roughness. Three of the six multilayered AC coatings tested exhibited extensive fretting damage and generated large, deep, wear scars. Cohesive failure of the AC coating was observed in the low contact stress areas of the fretting scars. The remaining AC-coated specimens experienced only slight polishing wear. The reason for the different behavior within the AC-coated specimens is not clear at the present time. The unmodified Ti6Al4V surfaces experienced severe surface damage consistent with the adhesive galling mechanism to which these alloys are susceptible.

  7. Advanced glycation end-products: modifiable environmental factors profoundly mediate insulin resistance

    PubMed Central

    Ottum, Mona S.; Mistry, Anahita M.

    2015-01-01

    Advanced glycation end-products are toxic by-products of metabolism and are also acquired from high-temperature processed foods. They promote oxidative damage to proteins, lipids and nucleotides. Aging and chronic diseases are strongly associated with markers for oxidative stress, especially advanced glycation end-products, and resistance to peripheral insulin-mediated glucose uptake. Modifiable environmental factors including high levels of refined and simple carbohydrate diets, hypercaloric diets and sedentary lifestyles drive endogenous formation of advanced glycation end-products via accumulation of highly reactive glycolysis intermediates and activation of the polyol/aldose reductase pathway producing high intracellular fructose. High advanced glycation end-products overwhelm innate defenses of enzymes and receptor-mediated endocytosis and promote cell damage via the pro-inflammatory and pro-oxidant receptor for advanced glycation end-products. Oxidative stress disturbs cell signal transduction, especially insulin-mediated metabolic responses. Here we review emerging evidence that restriction of dietary advanced glycation end-products significantly reduces total systemic load and insulin resistance in animals and humans in diabetes, polycystic ovary syndrome, healthy populations and dementia. Of clinical importance, this insulin sensitizing effect is independent of physical activity, caloric intake and adiposity level. PMID:26236094

  8. Quercetin-Based Modified Porous Silicon Nanoparticles for Enhanced Inhibition of Doxorubicin-Resistant Cancer Cells.

    PubMed

    Liu, Zehua; Balasubramanian, Vimalkumar; Bhat, Chinmay; Vahermo, Mikko; Mäkilä, Ermei; Kemell, Marianna; Fontana, Flavia; Janoniene, Agne; Petrikaite, Vilma; Salonen, Jarno; Yli-Kauhaluoma, Jari; Hirvonen, Jouni; Zhang, Hongbo; Santos, Hélder A

    2017-02-01

    One of the most challenging obstacles in nanoparticle's surface modification is to achieve the concept that one ligand can accomplish multiple purposes. Upon such consideration, 3-aminopropoxy-linked quercetin (AmQu), a derivative of a natural flavonoid inspired by the structure of dopamine, is designed and subsequently used to modify the surface of thermally hydrocarbonized porous silicon (PSi) nanoparticles. This nanosystem inherits several advanced properties in a single carrier, including promoted anticancer efficiency, multiple drug resistance (MDR) reversing, stimuli-responsive drug release, drug release monitoring, and enhanced particle-cell interactions. The anticancer drug doxorubicin (DOX) is efficiently loaded into this nanosystem and released in a pH-dependent manner. AmQu also effectively quenches the fluorescence of the loaded DOX, thereby allowing the use of the nanosystem for monitoring the intracellular drug release. Furthermore, a synergistic effect with the presence of AmQu is observed in both normal MCF-7 and DOX-resistant MCF-7 breast cancer cells. Due to the similar structure as dopamine, AmQu may facilitate both the interaction and internalization of PSi into the cells. Overall, this PSi-based platform exhibits remarkable superiority in both multifunctionality and anticancer efficiency, making this nanovector a promising system for anti-MDR cancer treatment.

  9. Leaf Treatments with a Protein-Based Resistance Inducer Partially Modify Phyllosphere Microbial Communities of Grapevine

    PubMed Central

    Cappelletti, Martina; Perazzolli, Michele; Antonielli, Livio; Nesler, Andrea; Torboli, Esmeralda; Bianchedi, Pier L.; Pindo, Massimo; Puopolo, Gerardo; Pertot, Ilaria

    2016-01-01

    Protein derivatives and carbohydrates can stimulate plant growth, increase stress tolerance, and activate plant defense mechanisms. However, these molecules can also act as a nutritional substrate for microbial communities living on the plant phyllosphere and possibly affect their biocontrol activity against pathogens. We investigated the mechanisms of action of a protein derivative (nutrient broth, NB) against grapevine downy mildew, specifically focusing on the effects of foliar treatments on plant defense stimulation and on the composition and biocontrol features of the phyllosphere microbial populations. NB reduced downy mildew symptoms and induced the expression of defense-related genes in greenhouse- and in vitro-grown plants, indicating the activation of grapevine resistance mechanisms. Furthermore, NB increased the number of culturable phyllosphere bacteria and altered the composition of bacterial and fungal populations on leaves of greenhouse-grown plants. Although, NB-induced changes on microbial populations were affected by the structure of indigenous communities originally residing on grapevine leaves, degrees of disease reduction and defense gene modulation were consistent among the experiments. Thus, modifications in the structure of phyllosphere populations caused by NB application could partially contribute to downy mildew control by competition for space or other biocontrol strategies. Particularly, changes in the abundance of phyllosphere microorganisms may provide a contribution to resistance induction, partially affecting the hormone-mediated signaling pathways involved. Modifying phyllosphere populations by increasing natural biocontrol agents with the application of selected nutritional factors can open new opportunities in terms of sustainable plant protection strategies. PMID:27486468

  10. Enhanced antimicrobial properties, cytocompatibility, and corrosion resistance of plasma-modified biodegradable magnesium alloys.

    PubMed

    Zhao, Ying; Jamesh, Mohammed Ibrahim; Li, Wing Kan; Wu, Guosong; Wang, Chenxi; Zheng, Yufeng; Yeung, Kelvin W K; Chu, Paul K

    2014-01-01

    Magnesium alloys are potential biodegradable materials and have received increasing attention due to their outstanding biological performance and mechanical properties. However, rapid degradation in the physiological environment and potential toxicity limit clinical applications. Recently, special magnesium-calcium (Mg-Ca) and magnesium-strontium (Mg-Sr) alloys with biocompatible chemical compositions have been reported, but the rapid degradation still does not meet clinical requirements. In order to improve the corrosion resistance, a rough, hydrophobic and ZrO(2)-containing surface film is fabricated on Mg-Ca and Mg-Sr alloys by dual zirconium and oxygen ion implantation. Weight loss measurements and electrochemical corrosion tests show that the corrosion rate of the Mg-Ca and Mg-Sr alloys is reduced appreciably after surface treatment. A systematic investigation of the in vitro cellular response and antibacterial capability of the modified binary magnesium alloys is performed. The amounts of adherent bacteria on the Zr-O-implanted and Zr-implanted samples diminish remarkably compared to the unimplanted control. In addition, significantly enhanced cell adhesion and proliferation are observed from the Zr-O-implanted sample. The results suggest that dual zirconium and oxygen ion implantation, which effectively enhances the corrosion resistance, in vitro biocompatibility and antimicrobial properties of Mg-Ca and Mg-Sr alloys, provides a simple and practical means to expedite clinical acceptance of biodegradable magnesium alloys.

  11. Modified Jeans instability of magnetized viscous spin 1/2 quantum plasma with resistive effects and Hall current

    NASA Astrophysics Data System (ADS)

    Sharma, Prerana; Chhajlani, R. K.

    2014-07-01

    The effect of Hall current on Jeans self-gravitational instability is examined for finitely conducting dense quantum viscous plasma in the presence of spin generated magnetization. The basic equations of the problem are constructed using quantum magneto hydrodynamic (QMHD) model. The Hall and resistivity terms are incorporated in the idealized Ohm's law and spin induced magnetization and viscosity terms are incorporated to the momentum equations. The general dispersion relation is found to be modified due to the presence of Hall current, electrical resistivity and viscosity parameter along with the spin induced magnetization. The dispersion relation is further reduced for both transverse and longitudinal mode of propagations. In the transverse mode of propagation the Jeans condition of instability is modified due to Alfven velocity, magnetization parameter and quantum corrections, and the growth rate of instability is found to be modified due to the electrical resistivity, viscosity, magnetization parameter and quantum corrections but remains unaffected by the presence of Hall current. In longitudinal direction of propagation the gravitational mode is affected due to the viscosity and quantum parameter while the Jeans condition of instability depends only upon the quantum correction. The Alfven mode in longitudinal direction gets modified due to the electrical resistivity, Hall current, viscosity and magnetization parameter however, it is found to be independent of quantum corrections. The numerical observations are also presented to show the effect of electrical resistivity, magnetization and quantum corrections on the growth rate of instability.

  12. Premixed, injectable PLA-modified calcium deficient apatite biocement (cd-AB) with washout resistance.

    PubMed

    Wu, Fan; Ngothai, Yung; Wei, Jie; Liu, Changsheng; O'Neill, Brian; Wu, Yuequn

    2012-04-01

    By using a non-aqueous solution as the mixing liquid, the washout resistance of the calcium deficient apatite biocement (cd-AB) was significantly improved, over that of the conventional method of using cd-AB with water as the liquid phase. In this study, premixed and injectable cd-AB was prepared, which had the advantage of being stable in the syringe and hardens only after being delivered to the defect area. The cd-AB powder with a Ca/P ratio of 1.5 consists of a mixture of tetracalcium phosphate (TTCP) and dicalcium phosphate anhydrous (DCPA). A solution of polylactide (PLA) in N-methyl-2-pyrrolidone (NMP) was used as the liquid phase of the premixed cd-AB. The premixed cd-AB paste injected into an aqueous environment exhibited excellent washout resistance. The premixed cd-AB had longer setting time and lower compressive strength than conventional cd-AB. The hydration products of premixed cd-AB were a mixture of calcium deficient hydroxyapatite (cd-HA) and PLA. In vitro Tris-HCl immersion tests demonstrated that the premixed cd-AB could be degradable. The results revealed that the premixed cd-AB was cytocompatible and had no adverse effects on the attachment and proliferation of MG-63 osteoblast-like cells in vitro. The most distinct advantages of premixed and injectable PLA-modified cd-AB were its excellent washout resistance and in vitro degradability, suggesting that it may be a promising candidate for bone repair.

  13. Analogue-resistant mutants of Azotobacter chroococcum derepressed for nitrogenase activity and early ammonia excretion having potential as inoculants for cereal crops.

    PubMed

    Lakshminarayana, K; Shukla, B; Sindhu, S S; Kumari, P; Narula, N; Sheoran, R K

    2000-04-01

    Spontaneous mutants resistant to methionine sulfoximine (Msx), methyl alanine (Mal) and methyl ammonium chloride (Mac) were derived from A. chroococcum strain A103. Msx and Mal-resistant mutants expressed 1.73 to 10.98% of the fully derepressed nitrogenase activity when grown in Burk's medium containing ammonium acetate. Mac-resistant mutants did not express nitrogenase activity in ammonium acetate supplemented medium. The mutants excreted ammonia even after 2 days of growth and some mutants excreted more ammonia as compared to the parent. Selected mutants were inoculated on wheat (Triticum aestivum) and barley (Hordeum vulgare) under field conditions. Majority of the derepressed mutants increased grain yield of wheat and barley varying from 1.2 to 33.3%. However, host-dependent effects on grain yield were observed with different mutants. Two mutants, Mal 27 and Mac 19 showed significant increase in grain yields of both the crops. The results suggest that metabolic analogue-resistant mutants of Azotobacter have potential for use as a biofertilizer for cereal crops.

  14. Identification and quantification of three genetically modified insect resistant cotton lines using conventional and TaqMan real-time polymerase chain reaction methods.

    PubMed

    Yang, Litao; Pan, Aihu; Zhang, Kewei; Guo, Jinchao; Yin, Changsong; Chen, Jianxiu; Huang, Cheng; Zhang, Dabing

    2005-08-10

    As the genetically modified organisms (GMOs) labeling policies are issued in many countries, qualitative and quantitative polymerase chain reaction (PCR) techniques are increasingly used for the detection of genetically modified (GM) crops in foods. Qualitative PCR and TaqMan real-time quantitative PCR methods to detect and identify three varieties of insect resistant cotton, i.e., Mon531 cotton (Monsanto Co.) and GK19 and SGK321 cottons (Chinese Academy of Agricultural Sciences), which were approved for commercialization in China, were developed in this paper. Primer pairs specific to inserted DNAs, such as Cowpea trypsin inhibitor (CpTI) gene of SGK321 cotton and the specific junction DNA sequences containing partial Cry1A(c) gene and NOS terminator of Mon531, GK19, and SGK321 cotton varieties were designed to conduct the identified PCR assays. In conventional specific identified PCR assays, the limit of detection (LOD) was 0.05% for Mon531, GK19, or SGK321 in 100 ng of cotton genomic DNA for one reaction. Also, the multiplex PCR method for screening the three GM cottons was also established, which could save time and cost in practical detection. Furthermore, a real-time quantitative PCR assay based on TaqMan chemistry for detection of insect resistant gene, Cry1A(c), was developed. This assay also featured the use of a standard plasmid as a reference molecule, which contained both a specific region of the transgene Cry1A(c) and an endogenous stearoyl-acyl carrier protein desaturase (Sad1) gene of the cotton. In quantitative PCR assay, the quantification range was from 0.01 to 100% in 100 ng of the genome DNA template, and in the detection of 1.0, 3.0, and 5.0% levels of three insect resistant cotton lines, respectively, all of the relative standard deviations (RSDs) were less than 8.2% except for the GM cotton samples with 1.0% Mon531 or GK19, which meant that our real-time PCR assays involving the use of reference molecule were reliable and practical for GM

  15. Structural resistance of chemically modified 1-D nanostructured titanates in inorganic acid environment

    SciTech Connect

    Marinkovic, Bojan A.; Fredholm, Yann C.; Morgado, Edisson

    2010-10-15

    Sodium containing one-dimensional nanostructured layered titanates (1-D NSLT) were produced both from commercial anatase powder and Brazilian natural rutile mineral sands by alkali hydrothermal process. The 1-D NSLT were chemically modified with proton, cobalt or iron via ionic exchange and all products were additionally submitted to intensive inorganic acid aging (pH = 0.5) for 28 days. The morphology and crystal structure transformations of chemically modified 1-D NSLT were followed by transmission electron microscopy, powder X-ray diffraction, selected area electron diffraction and energy dispersive spectroscopy. It was found that the original sodium rich 1-D NSLT and cobalt substituted 1-D NSLT were completely converted to rutile nanoparticles, while the protonated form was transformed in a 70%-30% (by weight) anatase-rutile nanoparticles mixture, very similar to that of the well-known TiO{sub 2}-photocatalyst P25 (Degussa). The iron substituted 1-D NSLT presented better acid resistance as 13% of the original structure and morphology remained, the rest being converted in rutile. A significant amount of remaining 1-D NSLT was also observed after the acid treatment of the product obtained from rutile sand. The results showed that phase transformation of NSLT into titanium dioxide polymorph in inorganic acid conditions were controllable by varying the exchanged cations. Finally, the possibility to transform, through acid aging, 1-D NSLT obtained from Brazilian natural rutile sand into TiO{sub 2}-polymorphs was demonstrated for the first time to the best of authors' knowledge, opening path for producing TiO{sub 2}-nanoproducts with different morphologies through a simple process and from a low cost precursor.

  16. Characterization of microbial population of breba and main crops (Ficus carica) during cold storage: Influence of passive modified atmospheres (MAP) and antimicrobial extract application.

    PubMed

    Villalobos, María Del Carmen; Serradilla, Manuel Joaquín; Martín, Alberto; Hernández-León, Alejandro; Ruíz-Moyano, Santiago; Córdoba, María de Guía

    2017-05-01

    The purpose of this work was to study the changes of bacterial and fungal population of breba fruits such as 'Banane' and 'San Antonio' as well as 'Cuello Dama Negro', 'Cuello Dama Blanco' and 'San Antonio' fig cultivars stored in passive modified atmospheres (MAP) by the use of three different microperforated films (M10 with 16 holes; M30 with five holes and M50 with three holes). Moreover the effects of the application of aqueous soy polyphenolic antimicrobial extract (APE), alone or combined with MAP, were also studied for 'Cuello Dama Negro' and 'Cuello Dama Blanco' fig cultivars. Bacteria and fungi isolates were identified by PCR-RFLP of 16S rRNA and ITS regions, respectively, and subsequently sequence of the different patterns obtained. The results indicated that Pseudomonas gessardii, Pantoea agglomerans and Enterobacter asburiae were the main species of bacteria found in all the treatments studied. The fungal species identified were Aureobasidium pulullans, Cladosporium cladosporioides and Alternaria alternata, which were found in a lower percentage in fruit stored in MAP and fruits treated with antimicrobial extracts, as this treatments allowed to reduce the microbial growth of moulds and yeasts. Thus, the application of treatments such as M30, M50 or the combination of MAP with antimicrobial extract was highly effective to control fruit spoilage in fig and breba crops.

  17. [Genetically modified crops: promises and good intentions are not enough (refutation to Espinoza et aL 2004, Rev. Biol. Trop. 52 (3): 727-732)].

    PubMed

    García, Jaime E G

    2007-06-01

    The arguments presented by Espinoza et al. in their paper "Relationship of genetically modified crops with the environment and health of the Costa Rican human population" published in this journal (Rev. Biol. Trop. 52: 727-732, 2004) are questioned and refuted. The arguments are confronted with evidence offered by scientists and national and international independent organizations around the world (e.g. World Health Organization, Consumers International, Physicians and Scientists for Responsible Application of Science and Technology, International Union for Conservation of Nature and Natural Resources, the Council of the University of Costa Rica, and the Independent Science Panel) showing the current uncertainty and limitations of science in this area, as well as those of proposed and applied biosafety approaches. Environment, biodiversity and food security are so important and basic matters, that there is need of serious testing, particularly when promises seem to be based on environmentally dangerous ideas promoted half a century ago by the so called "green revolution". Debate should continue, based on a holistic analysis of facts and with ethical reasoning, avoiding emotional positions that can confuse virtual reality with reality.

  18. Impact of Adiposity on Incident Hypertension Is Modified by Insulin Resistance in Adults: Longitudinal Observation From the Bogalusa Heart Study.

    PubMed

    Zhang, Tao; Zhang, Huijie; Li, Shengxu; Li, Ying; Liu, Yaozhong; Fernandez, Camilo; Harville, Emily; Bazzano, Lydia; He, Jiang; Chen, Wei

    2016-01-01

    Adiposity and insulin resistance are closely associated with hypertension. This study aims to investigate whether the association between adiposity and hypertension is modified by insulin resistance. The cohort consisted of 1624 middle-aged normotensive black and white adults aged 18 to 43 years at baseline who followed for 16 years on average. Overweight/obesity at baseline was defined as body mass index (BMI) ≥25, and insulin resistance was measured using homeostasis model assessment of insulin resistance. Prevalence of incident hypertension was compared between the insulin-sensitive adiposity and insulin-resistant adiposity groups. The prevalence of incident hypertension was higher in the insulin-resistant adiposity than in the insulin-sensitive adiposity group (32.1% versus 22.1%, P<0.001). In multivariable logistic analyses, adjusted for baseline age, race, sex, follow-up years, and smoking, baseline insulin-resistant obesity was associated with incident hypertension (odds ratio, 1.9; P=0.008). Odds ratios did not differ between blacks and whites (P=0.238). Of note, the odds ratios of BMI associated with hypertension significantly increased with increasing quartiles of baseline homeostasis model assessment (odds ratio, 1.3, 1.1, 1.5, and 2.5 in quartiles I, II, III, and IV, respectively; P=0.006 for trend). Slopes of increasing follow-up blood pressure with baseline BMI, measured as regression coefficients (β), were significantly greater in insulin-resistant than in insulin-sensitive individuals (β=0.74 versus β=0.35 for systolic blood pressure, P=0.004 for difference; β=0.51 versus β=0.23 for diastolic blood pressure, P=0.001 for difference). These findings suggest that insulin resistance has a synergistic effect on the obesity-hypertension association in young adults, indicating that the role of adiposity in the development of hypertension is modified by insulin resistance.

  19. Chemical composition and resistance-modifying effect of the essential oil of Lantana camara Linn

    PubMed Central

    Sousa, Erlânio O.; Silva, Natálya F.; Rodrigues, Fabiola F. G.; Campos, Adriana R.; Lima, Sidney G.; Costa, José Galberto M.

    2010-01-01

    In this work, the chemical constituents, antibacterial and modulatory activities of the essential oil of Lantana camara Linn were studied. The essential oil was extracted from the leaves of L. camara by hydrodistillation method using Clevenger's apparatus and its chemical constituents were separated and identified by GC-MS, and the relative content of each constituent was determined by area normalization. Among the 25 identified components, bicyclogermacrene (19.42%), isocaryophyllene (16.70%), valecene (12.94%) and germacrene D (12.34%) were the main constituents. The oil was examined to antibacterial and modulatory activities against the multiresistant strains of Escherichia coli and Staphylococcus aureus by microdilution test. The results show an inhibitory activity to E. coli (MIC 512 μg/ml) and S. aureus (MIC 256 μg/ml). The synergism of the essential oil and aminoglycosides was verified too, with significant reduction of MICs (7 ×, 1250-5 μg/ml) against E. coli. It is suggested that the essential oil of Lantana camara Linn could be used as a source of plant-derived natural products with resistance-modifying activity. PMID:20668570

  20. Chemical composition and resistance-modifying effect of the essential oil of Lantana camara Linn.

    PubMed

    Sousa, Erlânio O; Silva, Natálya F; Rodrigues, Fabiola F G; Campos, Adriana R; Lima, Sidney G; Costa, José Galberto M

    2010-04-01

    In this work, the chemical constituents, antibacterial and modulatory activities of the essential oil of Lantana camara Linn were studied. The essential oil was extracted from the leaves of L. camara by hydrodistillation method using Clevenger's apparatus and its chemical constituents were separated and identified by GC-MS, and the relative content of each constituent was determined by area normalization. Among the 25 identified components, bicyclogermacrene (19.42%), isocaryophyllene (16.70%), valecene (12.94%) and germacrene D (12.34%) were the main constituents. The oil was examined to antibacterial and modulatory activities against the multiresistant strains of Escherichia coli and Staphylococcus aureus by microdilution test. The results show an inhibitory activity to E. coli (MIC 512 mug/ml) and S. aureus (MIC 256 mug/ml). The synergism of the essential oil and aminoglycosides was verified too, with significant reduction of MICs (7 x, 1250-5 mug/ml) against E. coli. It is suggested that the essential oil of Lantana camara Linn could be used as a source of plant-derived natural products with resistance-modifying activity.

  1. Corrosion resistance of Ti modified by chitosan-gold nanoparticles for orthopedic implantation.

    PubMed

    Farghali, R A; Fekry, A M; Ahmed, Rasha A; Elhakim, H K A

    2015-08-01

    Highly uniform bionanocomposite film composed of chitosan (CS) and gold nanoparticles (AuNPs) was synthesized successfully by electrodeposition method. The influence of AuNPs/CS bionanocomposite film on corrosion resistance of Ti was investigated. Surface morphology and compositional properties of the bionanocomposite were analyzed by scanning electron microscope (SEM), energy dispersive X-ray analysis (EDX), and X-ray photoelectron spectroscopy (XPS). Moreover, cyclic voltammetry (CV), open-circuit potential measurements (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (Rp) were used to examine the corrosion behavior in Hanks' solution. In comparison with Ti, Nyquist and Bode plots displayed higher impedance values and phase angles for AuNPs/CS biocomposite denoting a more protective passive film on Ti with inhibition efficiency (IE%) of 98%. An electric equivalent circuit with three time constants was modeled for the bionanocomposite. In addition, the antibacterial effect revealed the high efficiencies of the bionanocomposite film for inhibiting bacterial growth. The combination of the high biocompatibility of chitosan and strong adsorption ability of AuNPs make AuNPs/CS bionanocomposite promising candidate for modifying biomaterial surfaces for medical implantation applications.

  2. Protease-resistant modified human β-hexosaminidase B ameliorates symptoms in GM2 gangliosidosis model.

    PubMed

    Kitakaze, Keisuke; Mizutani, Yasumichi; Sugiyama, Eiji; Tasaki, Chikako; Tsuji, Daisuke; Maita, Nobuo; Hirokawa, Takatsugu; Asanuma, Daisuke; Kamiya, Mako; Sato, Kohei; Setou, Mitsutoshi; Urano, Yasuteru; Togawa, Tadayasu; Otaka, Akira; Sakuraba, Hitoshi; Itoh, Kohji

    2016-05-02

    GM2 gangliosidoses, including Tay-Sachs and Sandhoff diseases, are neurodegenerative lysosomal storage diseases that are caused by deficiency of β-hexosaminidase A, which comprises an αβ heterodimer. There are no effective treatments for these diseases; however, various strategies aimed at restoring β-hexosaminidase A have been explored. Here, we produced a modified human hexosaminidase subunit β (HexB), which we have termed mod2B, composed of homodimeric β subunits that contain amino acid sequences from the α subunit that confer GM2 ganglioside-degrading activity and protease resistance. We also developed fluorescent probes that allow visualization of endocytosis of mod2B via mannose 6-phosphate receptors and delivery of mod2B to lysosomes in GM2 gangliosidosis models. In addition, we applied imaging mass spectrometry to monitor efficacy of this approach in Sandhoff disease model mice. Following i.c.v. administration, mod2B was widely distributed and reduced accumulation of GM2, asialo-GM2, and bis(monoacylglycero)phosphate in brain regions including the hypothalamus, hippocampus, and cerebellum. Moreover, mod2B administration markedly improved motor dysfunction and a prolonged lifespan in Sandhoff disease mice. Together, the results of our study indicate that mod2B has potential for intracerebrospinal fluid enzyme replacement therapy and should be further explored as a gene therapy for GM2 gangliosidoses.

  3. Production of resistant starch by extrusion cooking of acid-modified normal-maize starch.

    PubMed

    Hasjim, Jovin; Jane, Jay-Lin

    2009-09-01

    The objective of this study was to utilize extrusion cooking and hydrothermal treatment to produce resistant starch (RS) as an economical alternative to a batch-cooking process. A hydrothermal treatment (110 degrees C, 3 d) of batch-cooked and extruded starch samples facilitated propagation of heat-stable starch crystallites and increased the RS contents from 2.1% to 7.7% up to 17.4% determined using AOAC Method 991.43 for total dietary fiber. When starch samples were batch cooked and hydrothermally treated at a moisture content below 70%, acid-modified normal-maize starch (AMMS) produced a greater RS content than did native normal-maize starch (NMS). This was attributed to the partially hydrolyzed, smaller molecules in the AMMS, which had greater mobility and freedom than the larger molecules in the NMS. The RS contents of the batch-cooked and extruded AMMS products after the hydrothermal treatment were similar. A freezing treatment of the AMMS samples at -20 degrees C prior to the hydrothermal treatment did not increase the RS content. The DSC thermograms and the X-ray diffractograms showed that retrograded amylose and crystalline starch-lipid complex, which had melting temperatures above 100 degrees C, accounted for the RS contents.

  4. Protease-resistant modified human β-hexosaminidase B ameliorates symptoms in GM2 gangliosidosis model

    PubMed Central

    Mizutani, Yasumichi; Sugiyama, Eiji; Tasaki, Chikako; Tsuji, Daisuke; Maita, Nobuo; Hirokawa, Takatsugu; Asanuma, Daisuke; Kamiya, Mako; Sato, Kohei; Setou, Mitsutoshi; Urano, Yasuteru; Togawa, Tadayasu; Otaka, Akira; Sakuraba, Hitoshi

    2016-01-01

    GM2 gangliosidoses, including Tay-Sachs and Sandhoff diseases, are neurodegenerative lysosomal storage diseases that are caused by deficiency of β-hexosaminidase A, which comprises an αβ heterodimer. There are no effective treatments for these diseases; however, various strategies aimed at restoring β-hexosaminidase A have been explored. Here, we produced a modified human hexosaminidase subunit β (HexB), which we have termed mod2B, composed of homodimeric β subunits that contain amino acid sequences from the α subunit that confer GM2 ganglioside–degrading activity and protease resistance. We also developed fluorescent probes that allow visualization of endocytosis of mod2B via mannose 6-phosphate receptors and delivery of mod2B to lysosomes in GM2 gangliosidosis models. In addition, we applied imaging mass spectrometry to monitor efficacy of this approach in Sandhoff disease model mice. Following i.c.v. administration, mod2B was widely distributed and reduced accumulation of GM2, asialo-GM2, and bis(monoacylglycero)phosphate in brain regions including the hypothalamus, hippocampus, and cerebellum. Moreover, mod2B administration markedly improved motor dysfunction and a prolonged lifespan in Sandhoff disease mice. Together, the results of our study indicate that mod2B has potential for intracerebrospinal fluid enzyme replacement therapy and should be further explored as a gene therapy for GM2 gangliosidoses. PMID:27018595

  5. WRR4, a broad-spectrum TIR-NB-LRR gene from Arabidopsis thaliana that confers white rust resistance in transgenic oilseed Brassica crops.

    PubMed

    Borhan, Mohammad Hossein; Holub, Eric B; Kindrachuk, Colin; Omidi, Mansour; Bozorgmanesh-Frad, Ghazaleh; Rimmer, S Roger

    2010-03-01

    White blister rust caused by Albugo candida (Pers.) Kuntze is a common and often devastating disease of oilseed and vegetable brassica crops worldwide. Physiological races of the parasite have been described, including races 2, 7 and 9 from Brassica juncea, B. rapa and B. oleracea, respectively, and race 4 from Capsella bursa-pastoris (the type host). A gene named WRR4 has been characterized recently from polygenic resistance in the wild brassica relative Arabidopsis thaliana (accession Columbia) that confers broad-spectrum white rust resistance (WRR) to all four of the above Al. candida races. This gene encodes a TIR-NB-LRR (Toll-like/interleukin-1 receptor-nucleotide binding-leucine-rich repeat) protein which, as with other known functional members in this subclass of intracellular receptor-like proteins, requires the expression of the lipase-like defence regulator, enhanced disease susceptibility 1 (EDS1). Thus, we used RNA interference-mediated suppression of EDS1 in a white rust-resistant breeding line of B. napus (transformed with a construct designed from the A. thaliana EDS1 gene) to determine whether defence signalling via EDS1 is functionally intact in this oilseed brassica. The eds1-suppressed lines were fully susceptible following inoculation with either race 2 or 7 isolates of Al. candida. We then transformed white rust-susceptible cultivars of B. juncea (susceptible to race 2) and B. napus (susceptible to race 7) with the WRR4 gene from A. thaliana. The WRR4-transformed lines were resistant to the corresponding Al. candida race for each host species. The combined data indicate that WRR4 could potentially provide a novel source of white rust resistance in oilseed and vegetable brassica crops.

  6. How can we improve crop genotypes to increase stress resilience and productivity in a future climate? A new crop screening method based on productivity and resistance to abiotic stress

    PubMed Central

    Thiry, Arnauld A.; Chavez Dulanto, Perla N.; Reynolds, Matthew P.; Davies, William J.

    2016-01-01

    The need to accelerate the selection of crop genotypes that are both resistant to and productive under abiotic stress is enhanced by global warming and the increase in demand for food by a growing world population. In this paper, we propose a new method for evaluation of wheat genotypes in terms of their resilience to stress and their production capacity. The method quantifies the components of a new index related to yield under abiotic stress based on previously developed stress indices, namely the stress susceptibility index, the stress tolerance index, the mean production index, the geometric mean production index, and the tolerance index, which were created originally to evaluate drought adaptation. The method, based on a scoring scale, offers simple and easy visualization and identification of resilient, productive and/or contrasting genotypes according to grain yield. This new selection method could help breeders and researchers by defining clear and strong criteria to identify genotypes with high resilience and high productivity and provide a clear visualization of contrasts in terms of grain yield production under stress. It is also expected that this methodology will reduce the time required for first selection and the number of first-selected genotypes for further evaluation by breeders and provide a basis for appropriate comparisons of genotypes that would help reveal the biology behind high stress productivity of crops. PMID:27677299

  7. Comparing the refuge strategy for managing the evolution of insect resistance under different reproductive strategies.

    PubMed

    Crowder, David W; Carrière, Yves

    2009-12-07

    Genetically modified (GM) crops are used extensively worldwide to control diploid agricultural insect pests that reproduce sexually. However, future GM crops will likely soon target haplodiploid and parthenogenetic insects. As rapid pest adaptation could compromise these novel crops, strategies to manage resistance in haplodiploid and parthenogenetic pests are urgently needed. Here, we developed models to characterize factors that could delay or prevent the evolution of resistance to GM crops in diploid, haplodiploid, and parthenogenetic insect pests. The standard strategy for managing resistance in diploid pests relies on refuges of non-GM host plants and GM crops that produce high toxin concentrations. Although the tenets of the standard refuge strategy apply to all pests, this strategy does not greatly delay the evolution of resistance in haplodiploid or parthenogenetic pests. Two additional factors are needed to effectively delay or prevent the evolution of resistance in such pests, large recessive or smaller non-recessive fitness costs must reduce the fitness of resistance individuals in refuges (and ideally also on GM crops), and resistant individuals must have lower fitness on GM compared to non-GM crops (incomplete resistance). Recent research indicates that the magnitude and dominance of fitness costs could be increased by using specific host-plants, natural enemies, or pathogens. Furthermore, incomplete resistance could be enhanced by engineering desirable traits into novel GM crops. Thus, the sustainability of GM crops that target haplodiploid or parthenogenetic pests will require careful consideration of the effects of reproductive mode, fitness costs, and incomplete resistance.

  8. Vancomycin modifies the expression of the agr system in multidrug-resistant Staphylococcus aureus clinical isolates

    PubMed Central

    Cázares-Domínguez, Vicenta; Ochoa, Sara A.; Cruz-Córdova, Ariadnna; Rodea, Gerardo E.; Escalona, Gerardo; Olivares, Alma L.; Olivares-Trejo, José de Jesús; Velázquez-Guadarrama, Norma; Xicohtencatl-Cortes, Juan

    2015-01-01

    Staphylococcus aureus is an opportunistic pathogen that colonizes human hosts and causes a wide variety of diseases. Two interacting regulatory systems called agr (accessory gene regulator) and sar (staphylococcal accessory regulator) are involved in the regulation of virulence factors. The aim of this study was to evaluate the effect of vancomycin on hld and spa gene expression during the exponential and post-exponential growth phases in multidrug-resistant (MDR) S. aureus. Methods: Antibiotic susceptibility was evaluated by the standard microdilution method. The phylogenetic profile was obtained by pulsed-field gel electrophoresis (PFGE). Polymorphisms of agr and SCCmec (staphylococcal cassette chromosome mec) were analyzed by multiplex polymerase chain reaction (PCR). The expression levels of hld and spa were analyzed by reverse transcription-PCR. An enzyme-linked immunosorbent assay (ELISA) was performed to detect protein A, and biofilm formation was analyzed via crystal violet staining. Results: In total, 60.60% (20/33) of S. aureus clinical isolates were MDR. Half (10/20) of the MDR S. aureus isolates were distributed in subcluster 10, with >90% similarity among them. In the isolates of this subcluster, a high prevalence (100%) for the agrII and the cassette SCCmec II polymorphisms was found. Our data showed significant increases in hld expression during the post-exponential phase in the presence and absence of vancomycin. Significant increases in spa expression, protein A production and biofilm formation were observed during the post-exponential phase when the MDR S. aureus isolates were challenged with vancomycin. Conclusion: The polymorphism agrII, which is associated with nosocomial isolates, was the most prevalent polymorphism in MDR S. aureus. Additionally, under our study conditions, vancomycin modified hld and spa expression in these clinical isolates. Therefore, vancomycin may regulate alternative systems that jointly participate in the regulation of

  9. HSP70-hom gene polymorphisms modify the association of diethylhexyl phthalates with insulin resistance.

    PubMed

    Kim, Jin Hee; Hong, Yun-Chul

    2014-12-01

    Recent studies suggest that diethylhexyl phthalates (DEHP) could contribute to the development of insulin resistance (IR) through oxidative stress, and that heat shock protein (HSP) could be related with the association between DEHP and IR. Therefore, we evaluated the effect modification of genetic polymorphisms of HSP70-hom, an oxidative stress related gene, on the relation between exposure to DEHP and IR. We obtained repeated blood and urine samples from 414 elderly female participants and measured urinary levels of mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) as metabolites of DEHP. We also measured serum levels of fasting glucose and insulin, derived the homeostatic model assessment (HOMA) index to assess IR, and genotyped two HSP70-hom polymorphisms (rs2227956 and rs2075800). A mixed effect model and penalized regression spline were used to estimate the associations between DEHP exposure and IR by genetic polymorphisms. The molar sum of MEHHP and MEOHP (∑DEHP) were significantly associated with HOMA (β = 0.30, P = 0.022). When stratified by genotype at rs2227956, the relationship between ∑DEHP and HOMA was statistically significant in participants with TT (β = 0.32, P = 0.048) or TC (β = 0.60, P = 0.008), while at rs2075800 there was a marginal association for the GA genotype (β = 0.33, P = 0.097). When haplotypes were constituted across the two HSP70-hom polymorphisms (rs2227956 and rs2075800), the association was apparent only in participants with the T-A haplotype (β = 0.39, P = 0.029). Our study suggests that HSP70-hom polymorphisms modify the association of DEHP with IR.

  10. Effect of Modified Wheat Gluten on Boiling Resistance Capacity of Pork Meatballs.

    PubMed

    Wang, Kai-Qiang; Luo, Shui-Zhong; Zhong, Xi-Yang; Cai, Ke-Zhou; Cai, Jing; Jiang, Shao-Tong; Zheng, Zhi

    2016-02-01

    The effect of the modified wheat gluten (MWG) extender, prepared by alcalase-based hydrolysis and transglutaminase cross-linking, on meatballs was analyzed in this study. Here, we studied the effect of MWG addition on the boiling resistance capacity of pork meatballs (MB-MWG) at high temperature (100 °C) and increasing cooking time; meatballs with added soy protein isolates (MB-SPI) and raw wheat gluten (MB-WG) were used as references. The cooking loss, water-holding capacity (WHC), and textural properties of meatballs were investigated. The results revealed that MB-MWG showed lower cooking loss, which decreased by 49.16% compared to meatballs without added extenders when treated for 30 min. The WHC of MB-MWG significantly increased from 80.68% to 95.42%. The hardness, springiness, and chewiness (textural properties) of MB-MWG were also significantly increased by 97.05%, 6.68%, and 121.96%, respectively. The addition of MWG increased the cross-linking in meatballs during the cooking process, as indicated by the higher G'. SDS-PAGE indicated an obvious decrease in myosin heavy chain in MB-MWG cooked for 30 min at 100 °C, which was attributed to the interaction of myofibrillar proteins in pork meat with MWG. The nuclear magnetic resonance T2 relaxation time patterns indicated that MWG addition caused an increase in the bound water content, and decrease in the free water content, of meatballs. An analysis of the microstructures revealed that the MB-MWG formed the most regular and compact network. Therefore, MWG could be used as an ingredient to facilitate the processing of meat products.

  11. Field Level RNAi-Mediated Resistance to Cassava Brown Streak Disease across Multiple Cropping Cycles and Diverse East African Agro-Ecological Locations

    PubMed Central

    Wagaba, Henry; Beyene, Getu; Aleu, Jude; Odipio, John; Okao-Okuja, Geoffrey; Chauhan, Raj Deepika; Munga, Theresia; Obiero, Hannington; Halsey, Mark E.; Ilyas, Muhammad; Raymond, Peter; Bua, Anton; Taylor, Nigel J.; Miano, Douglas; Alicai, Titus

    2017-01-01

    Cassava brown streak disease (CBSD) presents a serious threat to cassava production in East and Central Africa. Currently, no cultivars with high levels of resistance to CBSD are available to farmers. Transgenic RNAi technology was employed to combat CBSD by fusing coat protein (CP) sequences from Ugandan cassava brown streak virus (UCBSV) and Cassava brown streak virus (CBSV) to create an inverted repeat construct (p5001) driven by the constitutive Cassava vein mosaic virus promoter. Twenty-five plant lines of cultivar TME 204 expressing varying levels of small interfering RNAs (siRNAs) were established in confined field trials (CFTs) in Uganda and Kenya. Within an initial CFT at Namulonge, Uganda, non-transgenic TME 204 plants developed foliar and storage root CBSD incidences at 96–100% by 12 months after planting. In contrast, 16 of the 25 p5001 transgenic lines showed no foliar symptoms and had less than 8% of their storage roots symptomatic for CBSD. A direct positive correlation was seen between levels of resistance to CBSD and expression of transgenic CP-derived siRNAs. A subsequent CFT was established at Namulonge using stem cuttings from the initial trial. All transgenic lines established remained asymptomatic for CBSD, while 98% of the non-transgenic TME 204 stake-derived plants developed storage roots symptomatic for CBSD. Similarly, very high levels of resistance to CBSD were demonstrated by TME 204 p5001 RNAi lines grown within a CFT over a full cropping cycle at Mtwapa, coastal Kenya. Sequence analysis of CBSD causal viruses present at the trial sites showed that the transgenic lines were exposed to both CBSV and UCBSV, and that the sequenced isolates shared >90% CP identity with transgenic CP sequences expressed by the p5001 inverted repeat expression cassette. These results demonstrate very high levels of field resistance to CBSD conferred by the p5001 RNAi construct at diverse agro-ecological locations, and across the vegetative cropping cycle

  12. The food and environmental safety of Bt crops.

    PubMed

    Koch, Michael S; Ward, Jason M; Levine, Steven L; Baum, James A; Vicini, John L; Hammond, Bruce G

    2015-01-01

    Bacillus thuringiensis (Bt) microbial pesticides have a 50-year history of safety in agriculture. Cry proteins are among the active insecticidal ingredients in these pesticides, and genes coding for Cry proteins have been introduced into agricultural crops using modern biotechnology. The Cry gene sequences are often modified to enable effective expression in planta and several Cry proteins have been modified to increase biological activity against the target pest(s). Additionally, the domains of different but structurally conserved Cry proteins can be combined to produce chimeric proteins with enhanced insecticidal properties. Environmental studies are performed and include invertebrates, mammals, and avian species. Mammalian studies used to support the food and feed safety assessment are also used to support the wild mammal assessment. In addition to the NTO assessment, the environmental assessment includes a comparative assessment between the Bt crop and the appropriate conventional control that is genetically similar but lacks the introduced trait to address unintended effects. Specific phenotypic, agronomic, and ecological characteristics are measured in the Bt crop and the conventional control to evaluate whether the introduction of the insect resistance has resulted in any changes that might cause ecological harm in terms of altered weed characteristics, susceptibility to pests, or adverse environmental impact. Additionally, environmental interaction data are collected in field experiments for Bt crop to evaluate potential adverse effects. Further to the agronomic and phenotypic evaluation, potential movement of transgenes from a genetically modified crop plants into wild relatives is assessed for a new pest resistance gene in a new crop. This review summarizes the evidence for safety of crops containing Cry proteins for humans, livestock, and other non-target organisms.

  13. The food and environmental safety of Bt crops

    PubMed Central

    Koch, Michael S.; Ward, Jason M.; Levine, Steven L.; Baum, James A.; Vicini, John L.; Hammond, Bruce G.

    2015-01-01

    Bacillus thuringiensis (Bt) microbial pesticides have a 50-year history of safety in agriculture. Cry proteins are among the active insecticidal ingredients in these pesticides, and genes coding for Cry proteins have been introduced into agricultural crops using modern biotechnology. The Cry gene sequences are often modified to enable effective expression in planta and several Cry proteins have been modified to increase biological activity against the target pest(s). Additionally, the domains of different but structurally conserved Cry proteins can be combined to produce chimeric proteins with enhanced insecticidal properties. Environmental studies are performed and include invertebrates, mammals, and avian species. Mammalian studies used to support the food and feed safety assessment are also used to support the wild mammal assessment. In addition to the NTO assessment, the environmental assessment includes a comparative assessment between the Bt crop and the appropriate conventional control that is genetically similar but lacks the introduced trait to address unintended effects. Specific phenotypic, agronomic, and ecological characteristics are measured in the Bt crop and the conventional control to evaluate whether the introduction of the insect resistance has resulted in any changes that might cause ecological harm in terms of altered weed characteristics, susceptibility to pests, or adverse environmental impact. Additionally, environmental interaction data are collected in field experiments for Bt crop to evaluate potential adverse effects. Further to the agronomic and phenotypic evaluation, potential movement of transgenes from a genetically modified crop plants into wild relatives is assessed for a new pest resistance gene in a new crop. This review summarizes the evidence for safety of crops containing Cry proteins for humans, livestock, and other non-target organisms. PMID:25972882

  14. Resistance evolution to the first generation of genetically modified Diabrotica-active Bt-maize events by western corn rootworm: management and monitoring considerations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Western corn rootworm (Diabrotica virgifera virgifera; WCR) is a major coleopteran maize pest in North America and the EU, and has traditionally been managed through crop rotation and broad-spectrum soil insecticides. Genetically modified (GM) Bt-maize offers an additional means of control against W...

  15. Functional categorization of carbapenemase-mediated resistance by a combined genotyping and two-tiered Modified Hodge Test approach.

    PubMed

    Wong, Marcus H; Li, Yi; Chan, Edward W; Chen, Sheng

    2015-01-01

    The functional relationship between the detection of carbapenemase activity and phenotypic resistance in Gram-negative bacterial pathogens is often ill-defined. To address this issue, we developed a two-tiered Modified Hodge Test approach for carbapenemase detection and typing, in which the use of Pseudomonas aeruginosa strain PAO1 and Escherichia coli as indicator strains conferred two levels of sensitivities to carbapenemases. When applied alongside PCR genotyping tests for existence of known carbapenemase genes in 92 carbapenem resistant clinical isolates, this method is extremely useful in elucidating the relative role by which different enzymes contributed to the prevalent carbapenem-resistance phenotypes. With this study approach, we showed that the proportion of P. aeruginosa and Acinetobacter baumannii strains whose carbapenem resistance phenotypes could at least be partially attributed to carbapenemase were 34 and 89%, respectively. Our data also facilitates detailed functional categorization of carbapenem resistance phenotypes on the basis of the types and activities of detectable carbapenemase produced by the test organism. For example, six A. baumannii isolates harboring the bla OXA-51/23-like gene without detectable enzymatic activities were identified, suggesting that other resistance mechanisms may be involved. On the other hand, there were seven P. aeruginosa strains which produced carbapenemase phenotype without harboring known carbapenemase genes, inferring the existence of some hitherto unknown resistance determinants. Findings in this work therefore provide a comprehensive view on the cellular basis of carbapenem resistance phenotypes in major Gram-negative bacterial species, paving the way for development of novel strategies to reverse the effects of the major resistance mechanisms concerned.

  16. Large-scale test of the natural refuge strategy for delaying insect resistance to transgenic Bt crops.

    PubMed

    Jin, Lin; Zhang, Haonan; Lu, Yanhui; Yang, Yihua; Wu, Kongming; Tabashnik, Bruce E; Wu, Yidong

    2015-02-01

    The 'natural refuge strategy" for delaying insect resistance to transgenic cotton that produces insecticidal proteins from Bacillus thuringiensis (Bt) relies on refuges of host plants other than cotton that do not make Bt toxins. We tested this widely adopted strategy by comparing predictions from modeling with data from a four-year field study of cotton bollworm (Helicoverpa armigera) resistance to transgenic cotton producing Bt toxin Cry1Ac in six provinces of northern China. Bioassay data revealed that the percentage of resistant insects increased from 0.93% in 2010 to 5.5% in 2013. Modeling predicted that the percentage of resistant insects would exceed 98% in 2013 without natural refuges, but would increase to only 1.1% if natural refuges were as effective as non-Bt cotton refuges. Therefore, the results imply that natural refuges delayed resistance, but were not as effective as an equivalent area of non-Bt cotton refuges. The percentage of resistant insects with nonrecessive inheritance of resistance increased from 37% in 2010 to 84% in 2013. Switching to Bt cotton producing two or more toxins and integrating other control tactics could slow further increases in resistance.

  17. Genomic Modifiers of Natural Killer Cells, Immune Responsiveness and Lymphoid Tissue Remodeling Together Increase Host Resistance to Viral Infection

    PubMed Central

    Lee, Heather; Prince, Jessica; Stadnisky, Michael D.; Anderson, Monique; Nash, William; Rival, Claudia; Wei, Hairong; Gamache, Awndre; Farber, Charles R.; Tung, Kenneth; Brown, Michael G.

    2016-01-01

    The MHC class I Dk molecule supplies vital host resistance during murine cytomegalovirus (MCMV) infection. Natural killer (NK) cells expressing the Ly49G2 inhibitory receptor, which specifically binds Dk, are required to control viral spread. The extent of Dk-dependent host resistance, however, differs significantly amongst related strains of mice, C57L and MA/My. As a result, we predicted that relatively small-effect modifier genetic loci might together shape immune cell features, NK cell reactivity, and the host immune response to MCMV. A robust Dk-dependent genetic effect, however, has so far hindered attempts to identify additional host resistance factors. Thus, we applied genomic mapping strategies and multicolor flow cytometric analysis of immune cells in naive and virus-infected hosts to identify genetic modifiers of the host immune response to MCMV. We discovered and validated many quantitative trait loci (QTL); these were mapped to at least 19 positions on 16 chromosomes. Intriguingly, one newly discovered non-MHC locus (Cmv5) controlled splenic NK cell accrual, secondary lymphoid organ structure, and lymphoid follicle development during MCMV infection. We infer that Cmv5 aids host resistance to MCMV infection by expanding NK cells needed to preserve and protect essential tissue structural elements, to enhance lymphoid remodeling and to increase viral clearance in spleen. PMID:26845690

  18. Protein, cell and bacterial fouling resistance of polypeptoid-modified surfaces: effect of side-chain chemistry†

    PubMed Central

    Statz, Andrea R.; Barron, Annelise E.; Messersmith, Phillip B.

    2011-01-01

    Peptidomimetic polymers consisting of poly-N-substituted glycine oligomers (polypeptoids) conjugated to biomimetic adhesive polypeptides were investigated as antifouling surface coatings. The polymers were immobilized onto TiO2 surfaces via an anchoring peptide consisting of alternating residues of 3,4-dihydroxyphenylalanine (DOPA) and lysine. Three polypeptoid side-chain compositions were investigated for antifouling performance and stability toward enzymatic degradation. Ellipsometry and XPS analysis confirmed that purified polymers adsorbed strongly to TiO2 surfaces, and the immobilized polymers were resistant to enzymatic degradation as demonstrated by mass spectrometry. All polypeptoid-modified surfaces exhibited significant reductions in adsorption of lysozyme, fibrinogen and serum proteins, and were resistant to 3T3 fibroblast cell attachment for up to seven days. Long-term in vitro cell attachment studies conducted for six weeks revealed the importance of polypeptoid side-chain composition, with a methoxyethyl side chain providing superior long-term fouling resistance compared to hydroxyethyl and hydroxypropyl side chains. Finally, attachment of both gram-positive and gram-negative bacteria for up to four days under continuous-flow conditions was significantly reduced on the polypeptoid-modified surfaces compared to unmodified TiO2 surfaces. The results reveal the influence of polypeptoid side-chain chemistry on short-term and long-term protein, cell and bacterial fouling resistance. PMID:21472038

  19. High level of resistance to aztreonam and ticarcillin in Pseudomonas aeruginosa isolated from soil of different crops in Brazil.

    PubMed

    Pitondo-Silva, André; Martins, Vinicius Vicente; Fernandes, Ana Flavia Tonelli; Stehling, Eliana Guedes

    2014-03-01

    Pseudomonas aeruginosa can be found in water, soil, plants and, human and animal fecal samples. It is an important nosocomial pathogenic agent characterized by an intrinsic resistance to multiple antimicrobial agents and the ability to develop high-level (acquired) multidrug resistance through some mechanisms, among them, by the acquisition of plasmids and integrons, which are mobile genetic elements. In this study, 40 isolates from Brazilian soil were analyzed for antibiotic resistance, presence of integrons and plasmidial profile. The results demonstrated that the vast majority of the isolates have shown resistance for aztreonam (92.5%, n=37) and ticarcillin (85%, n=34), four isolates presented plasmids and eight isolates possess the class 1 integron. These results demonstrated that environmental isolates of P. aeruginosa possess surprising antibiotic resistance profile to aztreonam and ticarcillin, two antimicrobial agents for clinical treatment of cystic fibrosis patients and other infections occurred by P. aeruginosa.

  20. Simple screening strategy with only water bath needed for the identification of insect-resistant genetically modified rice.

    PubMed

    Zhang, Fang; Wang, Liu; Wang, Rui; Ying, Yibin; Wu, Jian

    2015-02-03

    An informative, with simple instrument needed, rapid and easily updated strategy for the identification of insect-resistant genetically modified (GM) rice has been described. Such strategy is based on a parallel series of loop-mediated isothermal amplification (LAMP) reactions targeting the rice endogenous gene sucrose phosphate synthase (Sps), the top two most frequently used genetic elements (Agrobacterium tumefaciens nopaline synthase terminator (Nos) and Cauliflower mosaic virus 35S promoter (CaMV35S)), and an insect-resistant specific gene (Cry1Ac) and detected visually by phosphate ion (Pi)-induced coloration reaction. After a logical judgment of visible readouts has been obtained, three popular insect-resistant GM rice events in China can be successfully identified within 35 min, using either microwell strips or paper bases.

  1. Interactions of tillage and cover crop on water, sediment, and pre-emergence herbicide loss in glyphosate-resistant cotton: implications for the control of glyphosate-resistant weed biotypes.

    PubMed

    Krutz, L Jason; Locke, Martin A; Steinriede, R Wade

    2009-01-01

    The need to control glyphosate [N-(phosphonomethyl)glycine]-resistant weed biotypes with tillage and preemergence herbicides in glyphosate-resistant crops (GRCs) is causing a reduction in no-tillage hectarage thereby threatening the advances made in water quality over the past decade. Consequently, if environmental gains afforded by GRCs are to be maintained, then an in-field best management practice (BMP) compatible with tillage is required for hectarage infested with glyphosate-resistant weed biotypes. Thus, 1 d after a preemergent application of fluometuron [N,N-dimethyl-N'-(3-(trifluoromethyl)phenyl)urea] (1.02 kg ha(-1)) and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] (1.18 kg ha(-1)) to a Dundee silt loam (fine-silty, mixed, active, thermic Typic Endoaqualf), simulated rainfall (60 mm h(-1)) was applied to 0.0002-ha microplots for approximately 1.25 h to elucidate tillage (no tillage [NT] and reduced tillage [RT])and cover crop (no cover [NC] and rye cover [RC]) effects on water, sediment, and herbicide loss in surface runoff. Regardless of tillage, RC delayed time-to-runoff 1.3-fold, reduced cumulative runoff volume 1.4-fold, and decreased cumulative sediment loss 4.7-fold. Cumulative fluometuron loss was not affected by tillage or cover crop. Conversely, total metolachlor loss was 1.3-fold lower in NT than RT and 1.4-fold lower in RC than NC. These data indicate that RC can be established in hectarage requiring tillage and potentially curtail water, sediment, and preemergence herbicide losses in the spring to levels equivalent to or better than that of NT, thereby protecting environmental gains provided by GRCs.

  2. Monitoring the agricultural landscape for insect resistance

    NASA Astrophysics Data System (ADS)

    Casas, Joseph; Glaser, J. A.; Copenhaver, Ken

    Farmers in 25 countries on six continents are using plant biotechnology to solve difficult crop production challenges and conserve the environment. In fact, 13.3 million farmers, which include 90 percent of the farming in developing countries, choose to plant biotech crops. Over the past decade, farmers increased area planted in genetically modified (GM) crops by more than 10 percent each year, thus increasing their farm income by more than 44 billion US dollars (1996-2007), and achieved economic, environmental and social benefits in crops such as soybeans, canola, corn and cotton. To date, total acres of biotech crops harvested exceed more than 2 billion with a proven 13-year history of safe use. Over the next decade, expanded adoption combined with current research on 57 crops in 63 countries will broaden the advantages of genetically modified foods for growers, consumers and the environment. Genetically modified (GM) crops with the ability to produce toxins lethal to specific insect pests are covering a larger percentage of the agricultural landscape every year. The United States department of Agriculture (USDA) estimated that 63 percent of corn and 65 percent of cotton contained these specific genetic traits in 2009. The toxins could protect billions of dollars of loss from insect damage for crops valued at greater than 165 billion US dollars in 2008. The stable and efficient production of these crops has taken on even more importance in recent years with their use, not only as a food source, but now also a source of fuel. It is in the best interest of the United States Environmental Protection Agency (USEPA) to ensure the continued efficacy of toxin producing GM crops as their use reduces pesticides harmful to humans and animals. However, population genetics models have indicated the risk of insect pests developing resistance to these toxins if a high percentage of acreage is grown in these crops. The USEPA is developing methods to monitor the agricultural

  3. Termite Resistance of Thermally-Modified Dendrocalamus asper (Schultes f.) Backer ex Heyne.

    PubMed

    Manalo, Ronniel D; Garcia, Carlos M

    2012-03-27

    The effects of thermal modification on the resistance of Dendrocalamus asper against Microcerotermes losbañosensis were investigated after exposure to virgin coconut oil at 140-200 °C for 30-120 min. The results showed that heat treatment significantly improved bamboo's resistance to termites based on mass losses and visual observations. The enhancement was highest at 200 °C. Prolonged treatment had a positive effect on the resistance at lower temperatures only.

  4. Using vegetative index and modified derivative for early detection of soybean plant injury from glyphosate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glyphosate is a non-selective, systemic herbicide highly toxic to sensitive plant species, and its use has seen a significant increase due to the increased adoption of genetically modified glyphosate-resistant crops since the mid-1990s. Glyphosate application for weed control in glyphosate-resistant...

  5. Corrosion resistance of enamel coating modified by calcium silicate and sand particle for steel reinforcement in concrete

    NASA Astrophysics Data System (ADS)

    Tang, Fujian

    Porcelain enamel has stable chemical property in harsh environments such as high temperature, acid and alkaline, and it can also chemically react with substrate reinforcing steel resulting in improved adherence strength. In this study, the corrosion resistances of enamel coating modified by calcium silicate and sand particles, which are designed for improved bond strength with surrounding concrete, were investigated in 3.5 wt% NaCl solution. It consists of two papers that describe the results of the study. The first paper investigates the corrosion behavior of enamel coating modified by calcium silicate applied to reinforcing steel bar in 3.5 wt% NaCl solution by OCP, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The coatings include a pure enamel, a mixed enamel that consists of 50% pure enamel and 50% calcium silicate by weight, and a double enamel that has an inner pure enamel layer and an outer mixed enamel layer. Electrochemical tests demonstrates that both pure and double enamel coatings can significantly improve corrosion resistance, while the mixed enamel coating offers very little protection due to connected channels. The second paper is focused on the electrochemical characteristics of enamel coating modified by sand particle applied to reinforcing steel bar in 3.5 wt% NaCl solution by EIS. Six percentages by weight are considered including 5%, 10%, 20%, 30%, 50%, and 70%. Results reveal that addition of sand particle does not affect its corrosion resistance significantly. Most of the sand particles can wet very well with enamel body, while some have a weak zone which is induced during the cooling stage due to different coefficient of thermal expansion. Therefore, quality control of sand particle is the key factor to improve its corrosion resistance.

  6. Gene Amplification Is A Mechanism For Rapid Weed Evolution To Herbicide Resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The herbicide glyphosate became widely used in the U.S. and other parts of the world following the introduction of glyphosate-resistant crops. These crops were created by introduction of a modified 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene, the herbicide target site. Increased use of ...

  7. Tiered tests to assess the environmental risk of fitness changes in hybrids between transgenic crops and wild relatives: the example of virus resistant Brassica napus.

    PubMed

    Raybould, Alan; Cooper, Ian

    2005-01-01

    Over the last 20 years, there has been much research aimed at improving environmental risk assessment of transgenic crops. Despite large amounts of data, decisions to allow or prohibit the release of transgenic crops remain confused and controversial. We argue that part of the reason for confusion is the lack of clear definitions of components of the environment that should be protected, and, as a consequence, there is no way to judge the relevance of data collected under the auspices of 'environmental risk assessment'. Although this criticism applies to most aspects of environmental risk assessment of transgenic crops, it is most pertinent to effects that might result from an increase in plant fitness, often referred to as increased weediness. Environmental risk assessment of weediness is regarded as complicated: an increase in the fitness of a transgenic plant compared with non-transgenic counterparts will be the result of an interaction between the altered plant phenotype and an enormous number of environmental variables. This has led to the idea that risk assessment of weediness needs to "understand" these interactions, with the implication that exhaustive data are required. Here we argue that environmental risk assessment of the weediness of transgenic plants need not be complicated. Analysis of the conditions that must be met for increased weediness to occur suggests a series of studies that starts with simple tests in the laboratory under "worst case" assumptions, and becomes increasingly complex and realistic should the simpler studies not indicate negligible risk with sufficient certainty. We illustrate how the approach might work for assessing the risks of increased weediness using the example of possible introgression of a gene for Turnip mosaic virus (TuMV) resistance from oilseed rape to certain wild Brassica species.

  8. Modified live Edwardsiella ictaluri vaccine, AQUAVAC-ESC, lacks multidrug resistance plasmids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plasmid mediated antibiotic resistance was first discovered in Edwardsiella ictaluri in the early 1990’s, and in 2007 an E. ictaluri isolate harboring an IncA/C plasmid was recovered from a moribund channel catfish infected with the bacterium. Due to the identification of multidrug resistance plasm...

  9. Cover Crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cover crops are great tools to improve soil quality and health, and great tools to increase carbon sequestration. They are nutrient management tools that can help scavenge nitrate, cycle nitrogen to the following crop, mine NO3 from groundwater, and increase nitrogen use efficiency of cropping syste...

  10. Road asphalt modifiers based on oil-resistant rubbers and products of thermal transformations of coals

    SciTech Connect

    Sharypov, V.I.; Kiselev, V.P.; Beregovtsova, N.G.; Bugaenko, M.B.; Kuznetsov, B.N.

    2008-07-15

    The properties of asphalt binder modifiers prepared by dissolving butadiene-acrylonitrile rubbers and their production waste in liquid products of heat treatment of various brands of coal were studied.

  11. Altered pesticide use on transgenic crops and the associated general impact from an environmental perspective.

    PubMed

    Kleter, Gijs A; Bhula, Raj; Bodnaruk, Kevin; Carazo, Elizabeth; Felsot, Allan S; Harris, Caroline A; Katayama, Arata; Kuiper, Harry A; Racke, Kenneth D; Rubin, Baruch; Shevah, Yehuda; Stephenson, Gerald R; Tanaka, Keiji; Unsworth, John; Wauchope, R Donald; Wong, Sue-Sun

    2007-11-01

    The large-scale commercial cultivation of transgenic crops has undergone a steady increase since their introduction 10 years ago. Most of these crops bear introduced traits that are of agronomic importance, such as herbicide or insect resistance. These traits are likely to impact upon the use of pesticides on these crops, as well as the pesticide market as a whole. Organizations like USDA-ERS and NCFAP monitor the changes in crop pest management associated with the adoption of transgenic crops. As part of an IUPAC project on this topic, recent data are reviewed regarding the alterations in pesticide use that have been observed in practice. Most results indicate a decrease in the amounts of active ingredients applied to transgenic crops compared with conventional crops. In addition, a generic environmental indicator -- the environmental impact quotient (EIQ) -- has been applied by these authors and others to estimate the environmental consequences of the altered pesticide use on transgenic crops. The results show that the predicted environmental impact decreases in transgenic crops. With the advent of new types of agronomic trait and crops that have been genetically modified, it is useful to take also their potential environmental impacts into account.

  12. Cross-Contamination of Residual Emerging Contaminants and Antibiotic Resistant Bacteria in Lettuce Crops and Soil Irrigated with Wastewater Treated by Sunlight/H2O2.

    PubMed

    Ferro, Giovanna; Polo-López, María I; Martínez-Piernas, Ana B; Fernández-Ibáñez, Pilar; Agüera, Ana; Rizzo, Luigi

    2015-09-15

    The sunlight/H2O2 process has recently been considered as a sustainable alternative option compared to other solar driven advanced oxidation processes (AOPs) in advanced treatment of municipal wastewater (WW) to be reused for crop irrigation. Accordingly, in this study sunlight/H2O2 was used as disinfection/oxidation treatment for urban WW treatment plant effluent in a compound parabolic collector photoreactor to assess subsequent cross-contamination of lettuce and soil by contaminants of emerging concern (CECs) (determined by QuEChERS extraction and LC-QqLIT-MS/MS analysis) and antibiotic resistant (AR) bacteria after irrigation with treated WW. Three CECs (carbamazepine (CBZ), flumequine (FLU), and thiabendazole (TBZ) at 100 μg L(-1)) and two AR bacterial strains (E. coli and E. faecalis, at 10(5) CFU mL(-1)) were spiked in real WW. A detection limit (DL) of 2 CFU mL(-1) was reached after 120 min of solar exposure for AR E. coli, while AR E. faecalis was more resistant to the disinfection process (240 min to reach DL). CBZ and TBZ were poorly removed after 90 min (12% and 50%, respectively) compared to FLU (94%). Lettuce was irrigated with treated WW for 5 weeks. CBZ and TBZ were accumulated in soil up to 472 ng g(-1) and 256 ng g(-1) and up-taken by lettuce up to 109 and 18 ng g(-1), respectively, when 90 min treated WW was used for irrigation; whereas no bacteria contamination was observed when the bacterial density in treated WW was below the DL. A proper treatment time (>90 min) should be guaranteed in order to avoid the transfer of pathogens from disinfected WW to irrigated crops and soil.

  13. Modified Cognitive Behavior Therapy for Severe, Treatment-Resistant Obsessive-Compulsive Disorder in an Adolescent With Autism Spectrum Disorder.

    PubMed

    Krebs, Georgina; Murray, Kim; Jassi, Amita

    2016-11-01

    There is a high rate of comorbidity between obsessive-compulsive disorder (OCD) and autism spectrum disorders (ASD). Standard cognitive-behavior therapy (CBT) protocols have been shown to be less effective in treating OCD in young people with ASD than in typically developing youth. This case study describes the treatment of an adolescent boy with severe, treatment-resistant OCD and ASD using a modified CBT approach. Modifications to a standard evidence-based CBT for OCD protocol included extended psychoeducation about anxiety; regular home-based sessions; and increased involvement of systems, including family and school. Multi-informant outcome data indicated significant improvements in OCD symptoms over the course of treatment with gains being maintained over a 12-month follow-up period. These findings demonstrate the potential efficacy of modified CBT for pediatric OCD in the context of ASD.

  14. What lies ahead in post-genomics era: a perspective on genetic improvement of crops for fungal disease resistance.

    PubMed

    Bhadauria, Vijai; Banniza, Sabine

    2014-01-01

    Fungal disease resistance breeding, especially for the lineage-exclusion (LEB) is essential to meet the caloric demand of ever-growing population as diseases, especially caused by fungal and fungus-like pathogens are posing a visible and imminent threat to sustainable world food supply. This article provides a fresh perspective on the application of genomics in the LEB.

  15. Genome Sequence of the Plant Endophyte Bacillus pumilus INR7, Triggering Induced Systemic Resistance in Field Crops.

    PubMed

    Jeong, Haeyoung; Choi, Soo-Keun; Kloepper, Joseph W; Ryu, Choong-Min

    2014-10-30

    Bacillus pumilus INR7 is an endophytic bacterium that has been commercialized as a biological control product against soilborne pathogens as well as foliar pathogens by direct antagonism and induction of systemic resistance. In the current study, we provide the genome sequence and a possible explanation of the function of strain INR7.

  16. Effect of cover crop and premergence herbicides on the control of ALS-Resistant Palmer Amaranth (Amaranthus palmeri) in peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Palmer amaranth is a troublesome species across most of the southeastern United States. Resistance to acetolactate synthase (ALS) inhibiting herbicides has made control of Palmer amaranth even more difficult for peanut producers. Field studies were conducted in 2007 and 2008 to determine the impac...

  17. Wear resistance of WC/Co HVOF-coatings and galvanic Cr coatings modified by diamond nanoparticles

    NASA Astrophysics Data System (ADS)

    Kandeva, M.; Grozdanova, T.; Karastoyanov, D.; Assenova, E.

    2017-02-01

    The efforts in the recent 20 years are related to search of ecological solutions in the tribotechnologies for the replacement of galvanic Cr coatings in the contact systems operating under extreme conditions: abrasion, erosion, cavitation, corrosion, shock and vibration loads. One of the solutions is in the composite coatings deposited by high velocity gas-flame process (HVOF). The present paper presents comparative study results for mechanical and tribological characteristics of galvanic Cr coatings without nanoparticles, galvanic Cr coatings modified by diamond nanoparticles NDDS of various concentration 0.6; 10; 15 и 20% obtained under three technological regimes, and composite WC-12Co coating. Comparative results about hardness, wear, wear resistance and friction coefficient are obtained for galvanic Cr-NDDS and WC-12Co coatings operating at equal friction conditions of dry friction on abrasive surface. The WC-12Co coating shows 5.4 to 7 times higher wear resistance compared to the galvanic Cr-NDDS coatings.

  18. Biofouling-resistant ceragenin-modified materials and structures for water treatment

    DOEpatents

    Hibbs, Michael; Altman, Susan J.; Jones, Howland D. T.; Savage, Paul B.

    2013-09-10

    This invention relates to methods for chemically grafting and attaching ceragenin molecules to polymer substrates; methods for synthesizing ceragenin-containing copolymers; methods for making ceragenin-modified water treatment membranes and spacers; and methods of treating contaminated water using ceragenin-modified treatment membranes and spacers. Ceragenins are synthetically produced antimicrobial peptide mimics that display broad-spectrum bactericidal activity. Alkene-functionalized ceragenins (e.g., acrylamide-functionalized ceragenins) can be attached to polyamide reverse osmosis membranes using amine-linking, amide-linking, UV-grafting, or silane-coating methods. In addition, silane-functionalized ceragenins can be directly attached to polymer surfaces that have free hydroxyls.

  19. Listeria monocytogenes is resistant to lysozyme through the regulation, not the acquisition, of cell wall-modifying enzymes.

    PubMed

    Burke, Thomas P; Loukitcheva, Anastasia; Zemansky, Jason; Wheeler, Richard; Boneca, Ivo G; Portnoy, Daniel A

    2014-11-01

    Listeria monocytogenes is a Gram-positive facultative intracellular pathogen that is highly resistant to lysozyme, a ubiquitous enzyme of the innate immune system that degrades cell wall peptidoglycan. Two peptidoglycan-modifying enzymes, PgdA and OatA, confer lysozyme resistance on L. monocytogenes; however, these enzymes are also conserved among lysozyme-sensitive nonpathogens. We sought to identify additional factors responsible for lysozyme resistance in L. monocytogenes. A forward genetic screen for lysozyme-sensitive mutants led to the identification of 174 transposon insertion mutations that mapped to 13 individual genes. Four mutants were killed exclusively by lysozyme and not other cell wall-targeting molecules, including the peptidoglycan deacetylase encoded by pgdA, the putative carboxypeptidase encoded by pbpX, the orphan response regulator encoded by degU, and the highly abundant noncoding RNA encoded by rli31. Both degU and rli31 mutants had reduced expression of pbpX and pgdA, yet DegU and Rli31 did not regulate each other. Since pbpX and pgdA are also present in lysozyme-sensitive bacteria, this suggested that the acquisition of novel enzymes was not responsible for lysozyme resistance, but rather, the regulation of conserved enzymes by DegU and Rli31 conferred high lysozyme resistance. Each lysozyme-sensitive mutant exhibited attenuated virulence in mice, and a time course of infection revealed that the most lysozyme-sensitive strain was killed within 30 min of intravenous infection, a phenotype that was recapitulated in purified blood. Collectively, these data indicate that the genes required for lysozyme resistance are highly upregulated determinants of L. monocytogenes pathogenesis that are required for avoiding the enzymatic activity of lysozyme in the blood.

  20. Listeria monocytogenes Is Resistant to Lysozyme through the Regulation, Not the Acquisition, of Cell Wall-Modifying Enzymes

    PubMed Central

    Burke, Thomas P.; Loukitcheva, Anastasia; Zemansky, Jason; Wheeler, Richard; Boneca, Ivo G.

    2014-01-01

    Listeria monocytogenes is a Gram-positive facultative intracellular pathogen that is highly resistant to lysozyme, a ubiquitous enzyme of the innate immune system that degrades cell wall peptidoglycan. Two peptidoglycan-modifying enzymes, PgdA and OatA, confer lysozyme resistance on L. monocytogenes; however, these enzymes are also conserved among lysozyme-sensitive nonpathogens. We sought to identify additional factors responsible for lysozyme resistance in L. monocytogenes. A forward genetic screen for lysozyme-sensitive mutants led to the identification of 174 transposon insertion mutations that mapped to 13 individual genes. Four mutants were killed exclusively by lysozyme and not other cell wall-targeting molecules, including the peptidoglycan deacetylase encoded by pgdA, the putative carboxypeptidase encoded by pbpX, the orphan response regulator encoded by degU, and the highly abundant noncoding RNA encoded by rli31. Both degU and rli31 mutants had reduced expression of pbpX and pgdA, yet DegU and Rli31 did not regulate each other. Since pbpX and pgdA are also present in lysozyme-sensitive bacteria, this suggested that the acquisition of novel enzymes was not responsible for lysozyme resistance, but rather, the regulation of conserved enzymes by DegU and Rli31 conferred high lysozyme resistance. Each lysozyme-sensitive mutant exhibited attenuated virulence in mice, and a time course of infection revealed that the most lysozyme-sensitive strain was killed within 30 min of intravenous infection, a phenotype that was recapitulated in purified blood. Collectively, these data indicate that the genes required for lysozyme resistance are highly upregulated determinants of L. monocytogenes pathogenesis that are required for avoiding the enzymatic activity of lysozyme in the blood. PMID:25157076

  1. HOX genes: Major actors in resistance to selective endocrine response modifiers.

    PubMed

    Jin, Kideok; Sukumar, Saraswati

    2016-04-01

    Long term treatment with therapies aimed at blocking the estrogen- (ER) or androgen receptor (AR) action often leads to the development of resistance to selective modulators of the estrogen receptor (SERMs) in ERα-positive breast cancer, or of the androgen receptor (SARMs) in AR-positive prostate cancer. Many underlying molecular events that confer resistance are known, but a unifying theme is yet to be revealed. Receptor tyrosine kinases (RTKs) such EGFR, ERBB2 and IGF1R are major mediators that can directly alter cellular response to the SERM, tamoxifen, but the mechanisms underlying increased expression of RTKs are not clear. A number of HOX genes and microRNAs and non-coding RNAs residing in the HOX cluster, have been identified as important independent predictors of endocrine resistant breast cancer. Recently, convincing evidence has accumulated that several members belonging to the four different HOX clusters contribute to endocrine therapy resistant breast cancer, but the mechanisms remain obscure. In this article, we have reviewed recent progress in understanding of the functioning of HOX genes and regulation of their expression by hormones. We also discuss, in particular, the contributions of several members of the HOX gene family to endocrine resistant breast cancer.

  2. Enhanced biofouling resistance of polyethersulfone membrane surface modified with capsaicin derivative and itaconic acid

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Gao, Xueli; Wang, Qun; Sun, Haijing; Wang, Xiaojuan; Gao, Congjie

    2015-11-01

    The culprit of biofouling is the reproduction of viable microorganisms on the membrane surface. Recently, functionalization of membrane surface with natural antibacterial agents has drawn great attention. This work presents the fabrication of antibiofouling polyethersulfone (PES) ultrafiltration (UF) membranes by UV-assisted photo grafting of capsaicin derivative (N-(4-hydroxy-3-methoxy-benzyl)-acrylamide, HMBA) and itaconic acid (IA) on the surface of PES membrane. Results of FTIR-ATR, water static contact angle (WSCA) and atomic force microscopy (AFM) analysis confirmed the successful grafting of HMBA and IA on the membrane surface. We investigated the antifouling and antibacterial properties of these membranes using BSA and Escherichia coli as the test model, respectively. During a 150-min test, the modified membranes show much lower flux decline (42.7% for PES-g-1H0I, 22.2% for PES-g-1H1I and 7.7% for PES-g-1H5I) when compared with the pristine membrane (flux declined by 77%). The modified membranes exhibit excellent antibacterial activity (nearly 100%) when UV irradiation time was 6 min. The morphological study suggested that the E. coli on the pristine membrane showed a regular and smooth surface while that on the modified membrane was disrupted, which validated the antibacterial activity of the modified membranes.

  3. A Modified Time-Delay Addition Method to Extract Resistive Leakage Current of MOSA

    NASA Astrophysics Data System (ADS)

    Khodsuz, Masume; Mirzaie, Mohammad

    2016-12-01

    Metal oxide surge arresters are one of the most important equipment for power system protection against switching and lightning over-voltages. High-energy stresses and environmental features are the main factors which degrade surge arresters. In order to verify surge arresters good condition, their monitoring is necessary. The majority of surge arrester monitoring techniques is based on total leakage current decomposition of their capacitive and resistive components. This paper introduces a new approach based on time-delay addition method to extract the resistive current from the total leakage current without measuring voltage signal. Surge arrester model for calculating leakage current has been performed in ATP-EMTP. In addition, the signal processing has been done using MATLAB software. To show the accuracy of the proposed method, experimental tests have been performed to extract resistive leakage current by the proposed method.

  4. Isothermal and cyclic oxidation resistance of boron-modified and germanium-doped silicide coatings for titanium alloys

    SciTech Connect

    Cockeram, B.; Rapp, R.A.

    1996-06-01

    Since titanium alloys with an adequate balance of mechanical properties and high-temperature oxidation resistance have not been developed, protective coatings are required. In the authors previous paper, B-modified and Ge-doped silicide diffusion coatings grown on Cp Ti, Ti-24Al-11Nb, Ti-22Al-27Nb, and Ti-20Al-22Nb by the halide-activated, pack-cementation method were described. In this study, isothermal and cyclic oxidation were used to evaluate the oxidation performance of these coatings in comparison to uncoated substrates. The rate-controlling mechanism for isothermal oxidation at high temperature was solid-state diffusion through a SiO{sub 2} scale, while the mechanism for low-temperature oxidation involved grain-boundary diffusion through TiO{sub 2}. Both isothermal and cyclic oxidation rates for the B-modified and Ge-doped silicide coatings were much slower than for pure TiSi{sub 2}. Oxygen contamination was not detected by microhardness measurements in the coated substrates after 200 oxidation cycles at 500-1000{degrees}C for the Ti-Al-Nb alloys, or at 500-875{degrees}C for Cp Ti. The excellent oxidation resistance for the optimum coating compositions is discussed.

  5. Copper modified austenitic stainless steel alloys with improved high temperature creep resistance

    DOEpatents

    Swindeman, R.W.; Maziasz, P.J.

    1987-04-28

    An improved austenitic stainless steel that incorporates copper into a base Fe-Ni-Cr alloy having minor alloying substituents of Mo, Mn, Si, T, Nb, V, C, N, P, B which exhibits significant improvement in high temperature creep resistance over previous steels. 3 figs.

  6. Overexpression of a modified plant thionin enhances disease resistance to citrus canker and Huanglongbing (HLB)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB or citrus greening disease) caused by Candidatus Liberibacter asiaticus (Las) is a great threat to the United States citrus industry. There are no proven strategies to eliminate HLB disease and no cultivar has been identified with strong HLB resistance. Citrus canker is also an ec...

  7. Modified CHROMagar Acinetobacter Medium for Direct Detection of Multidrug-Resistant Acinetobacter Strains in Nasal and Rectal Swab Samples

    PubMed Central

    Lee, Jacob; Kim, Taek-Kyung; Park, Min-Jeong; Kim, Han-Sung; Kim, Jae-Seok

    2013-01-01

    This study aimed to investigate whether CHROMagar Acinetobacter medium (CHROMagar, France) in combination with an antimicrobial supplement (modified CHROMagar Acinetobacter; CHROMagar, France) can be used for detecting and isolating multidrug-resistant Acinetobacter species (MRA) in nasal and rectal surveillance cultures. Nasal and rectal swab samples were collected from patients in an intensive care unit at a teaching hospital. The samples were used to inoculate modified CHROMagar Acinetobacter plates, which were examined after 24 and 48 hr of incubation at 37℃. Their susceptibility against the antimicrobial agents meropenem, imipenem, ciprofloxacin, and amikacin was analyzed using the Etest (bioMerieux, France). A total of 406 paired samples (406 nasal swabs and 406 rectal swabs) were obtained from 226 patients, and 120 samples (28 nasal and 28 rectal cultures, 47 nasal cultures only, and 17 rectal cultures only) yielded MRA. Seventy-five MRA isolates (18.5%) were recovered from the 406 nasal samples, and 45 MRA isolates (11.1%) were recovered from the 406 rectal samples. Of the 120 MRA isolates, 3 (2.5%) were detected only after 48 hr of incubation. The use of modified CHROMagar Acinetobacter together with nasal and rectal swabs and 1-day incubation is an effective surveillance tool for detecting MRA colonization. PMID:23667846

  8. Three-generation reproduction toxicity study of genetically modified rice with insect resistant genes.

    PubMed

    Hu, Yichun; Zhuo, Qin; Gong, Zhaolong; Piao, Jianhua; Yang, Xiaoguang

    2017-01-01

    In the present work, we evaluated the three generation reproductive toxicity of the genetically modified rice with insectresistant cry1Ac and sck genes. 120 Sprague-Dawley (SD) rats were divided into three groups which were fed with genetically modified rice diet (GM group), parental control rice diet (PR group) and AIN-93 control diet (both used as negative control) respectively. Bodyweight, food consumption, reproductive data, hematological parameters, serum chemistry, relative organ weights and histopathology for each generation were examined respectively. All the hematology and serum chemistry parameters, organ/body weight indicators were within the normal range or no change to the adverse direction was observed, although several differences in hematology and serum chemistry parameters (WBC, BUN, LDH of male rat, PLT, PCT, MPV of female rats), reproductive data (rate of morphologically abnormal sperm) were observed between GM rice group and two control groups. No macroscopic or histological adverse effects were found or considered as treatment-related, either. Overall, the three generation study of genetically modified rice with cry1Ac and sck genes at a high level showed no unintended adverse effects on rats's reproductive system.

  9. The present status of commercialized and developed biotech (GM) crops, results of evaluation of plum 'HoneySweet" for resistance to plum pox virus in the Czech Republic

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Commercialization of biotech (GM) crops started in 1996. A significant increase of 9 million hectars was realized in 1996-2009. In the years 2010-2011, it was already 12 million hectars (8 percent of total crop area). 16.7 million farmers in 29 countries planted 160 million hectars of GM crops in...

  10. Improved resistance of chemically-modified nanocellulose against thermally-induced depolymerization.

    PubMed

    Agustin, Melissa B; Nakatsubo, Fumiaki; Yano, Hiroyuki

    2017-05-15

    The study demonstrated the improvement in the resistance of nanocellulose against thermally-induced depolymerization by esterification with benzoyl (BNZ) and pivaloyl (PIV). The change in the degree of polymerization (DP) and molecular weight distribution (MWD) after thermal treatment in nitrogen and in air was investigated using viscometry and gel permeation chromatography. BNZ and PIV nanocellulose esters without α-hydrogens gave higher DP and narrower MWD than pure bacterial cellulose; and the acetyl and myristoyl esters, which possess α-hydrogens. Results also showed that when depolymerization is suppressed, thermal discoloration is also reduced. Resistance against depolymerization inhibits the formation of reducing ends which can be active sites for thermal discoloration. Finally, the findings suggest that benzoylation and pivaloylation can be an excellent modification technique to improve the thermal stability of nanocellulose.

  11. Allelic variation on murine chromosome 11 modifies host inflammatory responses and resistance to Bacillus anthracis.

    PubMed

    Terra, Jill K; France, Bryan; Cote, Christopher K; Jenkins, Amy; Bozue, Joel A; Welkos, Susan L; Bhargava, Ragini; Ho, Chi-Lee; Mehrabian, Margarete; Pan, Calvin; Lusis, Aldons J; Davis, Richard C; LeVine, Steven M; Bradley, Kenneth A

    2011-12-01

    Anthrax is a potentially fatal disease resulting from infection with Bacillus anthracis. The outcome of infection is influenced by pathogen-encoded virulence factors such as lethal toxin (LT), as well as by genetic variation within the host. To identify host genes controlling susceptibility to anthrax, a library of congenic mice consisting of strains with homozygous chromosomal segments from the LT-responsive CAST/Ei strain introgressed on a LT-resistant C57BL/6 (B6) background was screened for response to LT. Three congenic strains containing CAST/Ei regions of chromosome 11 were identified that displayed a rapid inflammatory response to LT similar to, but more severe than that driven by a LT-responsive allele of the inflammasome constituent NRLP1B. Importantly, increased response to LT in congenic mice correlated with greater resistance to infection by the Sterne strain of B. anthracis. The genomic region controlling the inflammatory response to LT was mapped to 66.36-74.67 Mb on chromosome 11, a region that encodes the LT-responsive CAST/Ei allele of Nlrp1b. However, known downstream effects of NLRP1B activation, including macrophage pyroptosis, cytokine release, and leukocyte infiltration could not fully explain the response to LT or the resistance to B. anthracis Sterne in congenic mice. Further, the exacerbated response in congenic mice is inherited in a recessive manner while the Nlrp1b-mediated response to LT is dominant. Finally, congenic mice displayed increased responsiveness in a model of sepsis compared with B6 mice. In total, these data suggest that allelic variation of one or more chromosome 11 genes in addition to Nlrp1b controls the severity of host response to multiple inflammatory stimuli and contributes to resistance to B. anthracis Sterne. Expression quantitative trait locus analysis revealed 25 genes within this region as high priority candidates for contributing to the host response to LT.

  12. Integrated weed management systems with herbicide-tolerant crops in the European Union: lessons learnt from home and abroad.

    PubMed

    Lamichhane, Jay Ram; Devos, Yann; Beckie, Hugh J; Owen, Micheal D K; Tillie, Pascal; Messéan, Antoine; Kudsk, Per

    2017-06-01

    Conventionally bred (CHT) and genetically modified herbicide-tolerant (GMHT) crops have changed weed management practices and made an important contribution to the global production of some commodity crops. However, a concern is that farm management practices associated with the cultivation of herbicide-tolerant (HT) crops further deplete farmland biodiversity and accelerate the evolution of herbicide-resistant (HR) weeds. Diversification in crop systems and weed management practices can enhance farmland biodiversity, and reduce the risk of weeds evolving herbicide resistance. Therefore, HT crops are most effective and sustainable as a component of an integrated weed management (IWM) system. IWM advocates the use of multiple effective strategies or tactics to manage weed populations in a manner that is economically and environmentally sound. In practice, however, the potential benefits of IWM with HT crops are seldom realized because a wide range of technical and socio-economic factors hamper the transition to IWM. Here, we discuss the major factors that limit the integration of HT crops and their associated farm management practices in IWM systems. Based on the experience gained in countries where CHT or GMHT crops are widely grown and the increased familiarity with their management, we propose five actions to facilitate the integration of HT crops in IWM systems within the European Union.

  13. Looking forward to genetically edited fruit crops.

    PubMed

    Nagamangala Kanchiswamy, Chidananda; Sargent, Daniel James; Velasco, Riccardo; Maffei, Massimo E; Malnoy, Mickael

    2015-02-01

    The availability of genome sequences for many fruit crops has redefined the boundaries of genetic engineering and genetically modified (GM) crop plants. However commercialization of GM crops is hindered by numerous regulatory and social hurdles. Here, we focus on recently developed genome-editing tools for fruit crop improvement and their importance from the consumer perspective. Challenges and opportunities for the deployment of new genome-editing tools for fruit plants are also discussed.

  14. Plant biotechnology: transgenic crops.

    PubMed

    Shewry, Peter R; Jones, Huw D; Halford, Nigel G

    2008-01-01

    Transgenesis is an important adjunct to classical plant breeding, in that it allows the targeted manipulation of specific characters using genes from a range of sources. The current status of crop transformation is reviewed, including methods of gene transfer, the selection of transformed plants and control of transgene expression. The application of genetic modification technology to specific traits is then discussed, including input traits relating to crop production (herbicide tolerance and resistance to insects, pathogens and abiotic stresses) and output traits relating to the composition and quality of the harvested organs. The latter include improving the nutritional quality for consumers as well as the improvement of functional properties for food processing.

  15. Structure–Activity Relationship Studies of the Tricyclic Indoline Resistance-Modifying Agent

    PubMed Central

    2015-01-01

    Previously we discovered a tricyclic indoline, N-[2-(6-bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-carbazol-4a-yl)ethyl]-4-chlorobenzene-1-sulfonamide (1, Of1), from bioinspired synthesis of a highly diverse polycyclic indoline alkaloid library, that selectively resensitizes methicillin-resistant Staphylococcus aureus strains to β-lactam antibiotics. Herein, we report a thorough structure–activity relationship investigation of 1, which identified regions of 1 that tolerate modifications without compromising activity and afforded the discovery of a more potent analogue with reduced mammalian toxicity. PMID:24694192

  16. Erwinia amylovora modifies phenolic profiles of susceptible and resistant apple through its type III secretion system.

    PubMed

    Pontais, Isabelle; Treutter, Dieter; Paulin, Jean-Pierre; Brisset, Marie-Noëlle

    2008-03-01

    Fire blight is a disease affecting Maloideae caused by the necrogenic bacterium Erwinia amylovora, which requires the type III protein secretion system (TTSS) for pathogenicity. Profiles of methanol-extractable leaf phenolics of two apple (Malus x domestica) genotypes with contrasting susceptibility to this disease were analyzed by HPLC after infection. Some qualitative differences were recorded between the constitutive compositions of the two genotypes but in both of them dihydrochalcones accounted for more than 90% of total phenolics. Principal component analysis separated leaves inoculated with a virulent wild-type strain from those inoculated with a non-pathogenic TTSS-defective mutant or with water. The changes in levels of the various groups of phenolics in response to the virulent bacterium were similar between the two genotypes, with a significant decrease of dihydrochalcones and a significant increase of hydroxycinnamate derivatives. Differences between genotypes were, however, recorded in amplitude and kinetic of variation in these groups. Occurrence of oxidation and polymerization reactions is proposed, based on the browning process of infected tissues, but whether some by-products act in defense as toxic compounds remain to be tested. Among direct antibacterial constitutive compounds present in apple leaves, the dihydrochalcone phloretin only was found at levels close to lethal concentrations in both genotypes. However, E. amylovora exhibited the ability to stabilize this compound at sublethal levels even in the resistant apple, rejecting the hypothesis of its involvement in the resistance of this genotype.

  17. Detergents modify proteinase K resistance of PrPSc in different transmissible spongiform encephalopathies (TSEs)

    PubMed Central

    Breyer, Johanna; Wemheuer, Wiebke M.; Wrede, Arne; Graham, Catherine; Benestad, Sylvie L.; Brenig, Bertram; Richt, Jürgen A.; Schulz-Schaeffer, Walter J.

    2012-01-01

    Prion diseases are diagnosed by the detection of their proteinase K-resistant prion protein fragment (PrPSc). Various biochemical protocols use different detergents for the tissue preparation. We found that the resistance of PrPSc against proteinase K may vary strongly with the detergent used. In our study, we investigated the influence of the most commonly used detergents on eight different TSE agents derived from different species and distinct prion disease forms. For a high throughput we used a membrane adsorbtion assay to detect small amounts of prion aggregates, as well as Western blotting. Tissue lysates were prepared using DOC, SLS, SDS or Triton X-100 in different concentrations and these were digested with various amounts of proteinase K. Detergents are able to enhance or diminish the detectability of PrPSc after proteinase K digestion. Depending on the kind of detergent, its concentration - but also on the host species that developed the TSE and the disease form or prion type - the detectability of PrPSc can be very different. The results obtained here may be helpful during the development or improvement of a PrPSc detection method and they point towards a detergent effect that can be additionally used for decontamination purposes. A plausible explanation for the detergent effects described in this article could be an interaction with the lipids associated with PrPSc that may stabilize the aggregates. PMID:22226540

  18. β-Diketone modified trastuzumab: a next-generation of Herceptin for resistant breast cancer cells?

    PubMed

    Lu, Jianguo; Pu, Jun; Lu, Xiaozhao; Fu, Haiyan; Wei, Mengying; Yang, Guodong

    2012-11-01

    Despite the initial efficacy of trastuzumab (commercially named Herceptin), acquired resistance in a majority of patients remains the biggest hurdle in breast cancer therapy. Recently, the Scripps Research Institute developed a method termed "instant immunity", in which antibodies (chemical programmed antibody) are rapidly induced by chemicals like β-diketone. When β-diketone is chemically linked to peptides specifically targeting cancer cells, the instant chemical programmed antibody would clear the cancer cells through antibody-dependent cellular cytotoxicity (ADCC) and complement-directed cytotoxicity (CDC). This novel strategy has a super advantage over passive immunization or immunization with recombinant or vectored vaccines because it induces a universal immune response and memory. Theoretically, combination of the cancer cell specific recognition advantage of trastuzumab and cancerous cell clearance of active immunization would be an option for trastuzumab resistant patients, which harbors both the advantages of cancer specific targeting of trastuzumab and active immunization of the "instant immunity", implicating a better clinical outcome. Further studies are needed to verify our hypothesis, which is worth validating.

  19. Detergents modify proteinase K resistance of PrP Sc in different transmissible spongiform encephalopathies (TSEs).

    PubMed

    Breyer, Johanna; Wemheuer, Wiebke M; Wrede, Arne; Graham, Catherine; Benestad, Sylvie L; Brenig, Bertram; Richt, Jürgen A; Schulz-Schaeffer, Walter J

    2012-05-25

    Prion diseases are diagnosed by the detection of their proteinase K-resistant prion protein fragment (PrP(Sc)). Various biochemical protocols use different detergents for the tissue preparation. We found that the resistance of PrP(Sc) against proteinase K may vary strongly with the detergent used. In our study, we investigated the influence of the most commonly used detergents on eight different TSE agents derived from different species and distinct prion disease forms. For a high throughput we used a membrane adsorption assay to detect small amounts of prion aggregates, as well as Western blotting. Tissue lysates were prepared using DOC, SLS, SDS or Triton X-100 in different concentrations and these were digested with various amounts of proteinase K. Detergents are able to enhance or diminish the detectability of PrP(Sc) after proteinase K digestion. Depending on the kind of detergent, its concentration - but also on the host species that developed the TSE and the disease form or prion type - the detectability of PrP(Sc) can be very different. The results obtained here may be helpful during the development or improvement of a PrP(Sc) detection method and they point towards a detergent effect that can be additionally used for decontamination purposes. A plausible explanation for the detergent effects described in this article could be an interaction with the lipids associated with PrP(Sc) that may stabilize the aggregates.

  20. Multifunctional hyaluronic acid modified graphene oxide loaded with mitoxantrone for overcoming drug resistance in cancer

    NASA Astrophysics Data System (ADS)

    Hou, Lin; Feng, Qianhua; Wang, Yating; Yang, Xiaomin; Ren, Junxiao; Shi, Yuyang; Shan, Xiaoning; Yuan, Yujie; Wang, Yongchao; Zhang, Zhenzhong

    2016-01-01

    Multifunctional nanosheets (HA-GO/Pluronic) with targeted chemo-photothermal properties were successfully developed for controlled delivery of mitoxantrone (MIT) to overcome multidrug resistance (MDR). In vitro release profiles displayed that both an acidic environment and a NIR laser could trigger and accelerate the release of a drug, which ensured nanosheets were stable in blood circulation and released MIT within tumor cells under laser irradiation. HA-GO/Pluronic nanosheets were taken up into MCF-7/ADR cells via receptor-mediated endocytosis, which further facilitated escapement of P-gp efflux. Compared with MIT solution, MIT/HA-GO/Pluronic showed greater cytotoxicity and increase in cellular MIT accumulation in MCF-7/ADR cells. Cell apoptosis and cell cycle arrest studies also revealed that MIT/HA-GO/Pluronic was more potent than MIT/GO/Pluronic and MIT solution. The anticancer efficacy in vivo was evaluated in MCF-7 and MCF-7/ADR-bearing mice, and inhibition of tumors by MIT/HA-GO/Pluronic with NIR laser irradiation was the most effective among all MIT formulations. In summary, the MIT/HA-GO/Pluronic system had striking functions such as P-gp reversible inhibitor and anticancer efficacy, and could present a promising platform for drug-resistant cancer treatment.

  1. Electrical resistivity imaging of hydrologic changes in an anthropogenically modified arid environment

    NASA Astrophysics Data System (ADS)

    Perkins, K. S.; Bedford, D.; Miller, D. M.; Sandquist, D. R.; Horowitz, C.

    2011-12-01

    Anthropogenic landscape modification, such as the emplacement of highways and railroads, has altered the natural hydrologic system by influencing surface-water flow paths, as well as the composition and distribution of biotic communities within the Mojave National Preserve, California, USA. Water sprinkling experiments along with electrical resistance imaging were conducted at two sites to evaluate changes in hydrology in terms of plant water availability and use. Previous studies have shown that plants on alluvial fans are more abundant near undisturbed ephemeral channels compared to channels where upslope catchments have been diverted by transportation corridor construction. During the sprinkling experiments, water was applied in one active channel upslope and another abandoned channel down slope from a railroad built less than 100 years ago. The abandoned channel is still evident, but has been disconnected from major runoff derived from higher elevations. Excavation at both sites showed weak soil development with fewer plant roots present beneath the abandoned channel. Electrical resistance imaging results indicate that water infiltrated rapidly at both sites and spread laterally throughout the 6-day monitoring period following the single sprinkling application. More water appears to be present beneath the abandoned channel after 6 days of redistribution. Hence we infer that plants do not preferentially root toward abandoned stream channels to exploit the enhanced infiltration as extensively as they do above the railroad where flow in ephemeral channels is an additional water source.

  2. Phase composition of heat-resisting alloy modified by ageing and alloyed by rhenium

    NASA Astrophysics Data System (ADS)

    Koneva, Nina; Nikonenko, Elena; Popova, Natalya; Gibert, Ivan; Kozlov, Eduard

    2016-11-01

    The paper presents the transmission electron microscope (TEM) investigations of the structure of Ni-Al-Cr-based superalloy which is obtained by directional crystallization technique. The structural TEM investigations are carried out in two stages: 1) annealing at 1150°C for 1 h and 2) annealing at 1100°C for 480 h. The qualitative and quantitative analysis is given for the structure, phase composition and morphology of heat-resisting alloy additionally alloyed by rhenium Re both in the original state and after thermal treatment. The heat-resisting alloy comprises ˜70 at % Ni, ˜17 at % Al and ˜5 at % Cr. The total amount of the primary alloying elements of Mo, W, Ta, Ti, Co, La was ˜7 at % and 0.4 at % Re. It is shown that the structure of the superalloy is represented by (γ + γ')-phase mixture which has a morphologically correct crystallographic orientation and quasi-monocrystalline structure. σ-phase is formed in this superalloy due to rhenium. Since Re distribution in the alloy is not uniform, only a part of (γ + γ')-phase quasi-cuboids is distorted. It is shown that Re modification distorts the ideal structure of (γ + γ')-phase quasi-cuboids and results in the formation of β-, χ-and σ-phases.

  3. Allergenicity assessment of genetically modified cucumber mosaic virus (CMV) resistant tomato (Solanum lycopersicon).

    PubMed

    Lin, Chih-Hui; Sheu, Fuu; Lin, Hsin-Tang; Pan, Tzu-Ming

    2010-02-24

    Cucumber mosaic virus (CMV) has been identified as the causal agent of several disease epidemics in most countries of the world. Insect-mediated virus diseases, such as those caused by CMV, caused remarkable loss of tomato (Solanum lycopersicon) production in Taiwan. With expression of the CMV coat protein gene (Cmvcp) in a local popular tomato cultivar L4783, transgenic tomato line R8 has showed consistent CMV resistance through T(0) to T(8). In this report, the allergenicity of the CMV coat protein (CMV cp) expressed in transgenic tomato R8 was assessed by investigation of the expression of the transgene source of protein, sequence similarity with known allergens, and resistance to pepsin hydrolysis. There is no known account for either the CMV or its coat protein being an allergen. The result of a bioinformatic search also showed no significant homology between CMV cp and any known allergen. The pepsin-susceptible property of recombinant CMV cp was revealed by a simulated gastric fluid (SGF) assay. Following the most recent FAO/WHO decision tree, all results have indicated that CMV cp was a protein with low possibility to be an allergen and the transgenic tomato R8 should be considered as safe as its host.

  4. Simultaneous enhancements of UV resistance and mechanical properties of polypropylene by incorporation of dopamine-modified clay.

    PubMed

    Phua, Si Lei; Yang, Liping; Toh, Cher Ling; Guoqiang, Ding; Lau, Soo Khim; Dasari, Aravind; Lu, Xuehong

    2013-02-01

    Inspired by the radical scavenging function of melanin-like materials and versatile adhesive ability of mussel-adhesion proteins, dopamine-modified clay (D-clay) was successfully incorporated into polypropylene (PP) using an amine-terminated PP oligomer as the compatibilizer. Although the PP/D-clay nanocomposites exhibit intercalated morphology, the incorporation of D-clay greatly improves the thermo-oxidative stability and UV resistance of PP owing to the strong radical scavenging ability of polydopamine (PDA) and large contact area between PP and the PDA coating on clay mineral. Moreover, the reinforcement effect brought by D-clay is fairly significant at very low clay loadings probably owing to the strong interfacial interactions between the layered silicates and the compatibilizer as well as that between the compatibilizer and the PP matrix. The work demonstrates that D-clay is a type of promising nanofiller for thermoplastics used for outdoor applications since it stabilizes and reinforces the polymers simultaneously.

  5. Comparing the impact of conventional pesticide and use of a transgenic pest-resistant crop on the beneficial carabid beetle Pterostichus melanarius.

    PubMed

    Mulligan, Evan A; Ferry, Natalie; Jouanin, Lise; Walters, Keith Fa; Port, Gordon R; Gatehouse, Angharad Mr

    2006-10-01

    The potential impact of a chemical pesticide control method has been compared with that of transgenic plants expressing a protease inhibitor conferring insect resistance by utilising a tritrophic system comprising the crop plant Brassica napus (L.) (Oilseed rape), the pest mollusc Deroceras reticulatum (Müller) and the predatory carabid beetle Pterostichus melanarius (Illiger). Cypermethrin, as the most widely used pesticide in UK oilseed rape (OSR) cultivation, was selected as the conventional treatment. OSR expressing a cysteine protease inhibitor, oryzacystatin-1 (OC-1), was the transgenic comparator. In feeding trials, D. reticulatum showed no significant long-term effects on measured life history parameters (survival, weight gain, food consumption) as a result of exposure to either the cypermethrin or OC-1 treatment. However, D. reticulatum was able to respond to the presence of the dietary inhibitor by producing two novel proteases following exposure to OC-1-expressing OSR. Similarly, P. melanarius showed no detectable alterations in mortality, weight gain or food consumption when feeding on D. reticulatum previously fed either pesticide-contaminated or GM plant material. Furthermore, as with the slug, a novel form of protease, approximately M(r) 27 kDa, was induced in the carabid in response to feeding on slugs fed OC-1-expressing OSR.

  6. Ethnicity Modifies the Relationships of Insulin Resistance, Inflammation, and Adiponectin With Obesity in a Multiethnic Asian Population

    PubMed Central

    Khoo, Chin Meng; Sairazi, Sarina; Taslim, Siska; Gardner, Daphne; Wu, Yi; Lee, Jeannette; van Dam, Rob M.; Shyong Tai, E.

    2011-01-01

    OBJECTIVE The development of obesity-related metabolic disorders varies with ethnicity. We examined whether ethnicity modifies the relationship between BMI and three metabolic pathways (insulin resistance, inflammation, and adiponectin) that are involved in the pathogenesis of diabetes and cardiovascular disease (CVD). RESEARCH DESIGN AND METHODS We analyzed data from 4,804 Chinese, Malay, and Asian-Indian residents of Singapore with complete data on insulin resistance (IR), C-reactive protein (CRP), and total adiponectin levels. Linear regression models with an interaction term ethnicity*BMI were used to evaluate whether ethnicity modifies the association between BMI and IR, CRP, and adiponectin. RESULTS In both uni- and multivariate analyses, BMI was directly associated with IR and CRP and inversely with adiponectin across all ethnic groups. When compared with Chinese and Malays, Asian-Indians had higher IR and CRP and lower adiponectin levels. The associations between BMI and its metabolic pathways were significantly stronger in Chinese than in other ethnic groups. The increase in IR and CRP and the decrease in adiponectin for each unit increase in BMI were greater in Chinese than in other ethnic groups. The findings were similar when waist circumference was used in the analyses instead of BMI. CONCLUSIONS The impact of BMI on IR, CRP, and adiponectin appears greater in Chinese as compared with other major Asian ethnic groups. This may partly explain the rapid increase in the prevalence of diabetes and CVD in Chinese populations and highlights the importance of weight management in Asian ethnic groups despite the apparently low levels of obesity. PMID:21464462

  7. Sequence-Modified Antibiotic Resistance Genes Provide Sustained Plasmid-Mediated Transgene Expression in Mammals.

    PubMed

    Lu, Jiamiao; Zhang, Feijie; Fire, Andrew Z; Kay, Mark A

    2017-03-30

    Conventional plasmid vectors are incapable of achieving sustained levels of transgene expression in vivo even in quiescent mammalian tissues because the transgene expression cassette is silenced. Transcriptional silencing results from the presence of the bacterial plasmid backbone or virtually any DNA sequence of >1 kb in length placed outside of the expression cassette. Here, we show that transcriptional silencing can be substantially forestalled by increasing the An/Tn sequence composition in the plasmid bacterial backbone. Increasing numbers of An/Tn sequences increased sustained transcription of both backbone sequences and adjacent expression cassettes. In order to recapitulate these expression profiles in compact and portable plasmid DNA backbones, we engineered the standard kanamycin or ampicillin antibiotic resistance genes, optimizing the number of An/Tn sequence without altering the encoded amino acids. The resulting vector backbones yield sustained transgene expression from mouse liver, providing generic DNA vectors capable of sustained transgene expression without additional genes or mammalian regulatory elements.

  8. Covalently modified silicon and diamond surfaces: resistance to nonspecific protein adsorption and optimization for biosensing.

    PubMed

    Lasseter, Tami L; Clare, Brian H; Abbott, Nicholas L; Hamers, Robert J

    2004-08-25

    We report the direct covalent functionalization of silicon and diamond surfaces with short ethylene glycol (EG) oligomers via photochemical reaction of the hydrogen-terminated surfaces with terminal vinyl groups of the oligomers, and the use of these monolayers to control protein binding at surfaces. Photochemical modification of Si(111) and polycrystalline diamond surfaces produces EG monolayers linked via Si-C bond formation (silicon) or C-C bond formation (diamond). X-ray photoelectron spectroscopy was used to characterize the monolayer composition. Measurements using fluorescently labeled proteins show that the EG-functionalized surfaces effectively resist nonspecific adsorption of proteins. Additionally, we demonstrate the use of mixed monolayers on silicon and diamond and apply these surfaces to control specific versus nonspecific binding to optimize a model protein sensing assay.

  9. Protein adsorption resistance of PVP-modified polyurethane film prepared by surface-initiated atom transfer radical polymerization

    NASA Astrophysics Data System (ADS)

    Yuan, Huihui; Qian, Bin; Zhang, Wei; Lan, Minbo

    2016-02-01

    An anti-fouling surface of polyurethane (PU) film grafted with Poly(N-vinylpyrrolidone) (PVP) was prepared through surface-initiated atom transfer radical polymerization (SI-ATRP). And the polymerization time was investigated to obtain PU films with PVP brushes of different lengths. The surface properties and protein adsorption of modified PU films were evaluated. The results showed that the hydrophilicity of PU-PVP films were improved with the increase of polymerization time, which was not positive correlation with the surface roughness due to the brush structure. Additionally, the protein resistance performance was promoted when prolonging the polymerization time. The best antifouling PU-PVP (6.0 h) film reduced the adsoption level of bovine serum albumin (BSA), lysozyme (LYS), and brovin serum fibrinogen (BFG) by 93.4%, 68.3%, 85.6%, respectively, compared to the unmodified PU film. The competitive adsorption of three proteins indicated that LYS preferentially adsorbed on the modified PU film, while BFG had the lowest adsorption selectivity. And the amount of BFG on PU-PVP (6.0 h) film reduced greatly to 0.08 μg/cm2, which was almost one-tenth of its adsorption from the single-protein system. Presented results suggested that both hydrophilicity and surface roughness might be the important factors in all cases of protein adsorption, and the competitive or selective adsorption might be related to the size of the proteins, especially on the non-charged films.

  10. Facile and scalable preparation of highly wear-resistance superhydrophobic surface on wood substrates using silica nanoparticles modified by VTES

    NASA Astrophysics Data System (ADS)

    Jia, Shanshan; Liu, Ming; Wu, Yiqiang; Luo, Sha; Qing, Yan; Chen, Haibo

    2016-11-01

    In this study, an efficient, facile method has been developed for fabricating superhydrophobic surfaces on wood substrates using silica nanoparticles modified by VTES. The as-prepared superhydrophobic wood surface had a water contact angle of 154° and water slide angle close to 0°. Simultaneously, this superhydrophobic wood showed highly durable and robust wear resistance when having undergone a long period of sandpaper abrasion or being scratched by a knife. Even under extreme conditions of boiling water, the superhydrophobicity of the as-prepared wood composite was preserved. Characterizations by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy showed that a typical and tough hierarchical micro/nanostructure was created on the wood substrate and vinyltriethoxysilane contributed to preventing the agglomeration of silica nanoparticles and serving as low-surface-free-energy substances. This superhydrophobic wood was easy to fabricate, mechanically resistant and exhibited long-term stability. Therefore, it is considered to be of significant importance in the industrial production of functional wood, especially for outdoor applications.

  11. Microstructural Study on Oxidation Resistance of Nonmodified and Platinum Modified Aluminide Coating

    NASA Astrophysics Data System (ADS)

    Zagula-Yavorska, Maryana; Sieniawski, Jan

    2014-03-01

    Platinum electroplating layers (3 and 7 μm thick) were deposited on the surface of the Inconel 713 LC, CMSX 4, and Inconel 625 Ni-base superalloys. Diffusion treatment at 1050°C for 2 h under argon atmosphere was performed after electroplating. Diffusion treated samples were aluminized according to the low activity CVD process at 1050°C for 8 h. The nonmodified aluminide coatings consist of NiAl phase. Platinum modification let to obtain the (Ni,Pt)Al phase in coatings. The coated samples were subjected to cyclic oxidation testing at 1100°C. It was discovered that increase of the platinum electroplating thickness from 3 to 7 μm provides the improvement of oxidation resistance of aluminide coatings. Increase of the platinum thickness causes decreases in weight change and decreases in parabolic constant during oxidation. The platinum provides the pure Al2O3 oxide formation, slow growth oxide layer, and delay the oxide spalling during heating-cooling thermal cycles.

  12. Hyaluronan and dextran modified tubes resist cellular activation with blood contact.

    PubMed

    Eckmann, David M; Tsai, Irene Y; Tomczyk, Nancy; Weisel, John W; Composto, Russell J

    2013-08-01

    This study was undertaken to evaluate the effects of thin film hyaluronic acid and dextran surface coatings to blunt cellular activation in a laboratory model of extracorporeal blood circulation. The inner lumen surface of polyurethane (PU) and poly(vinyl) chloride (PVC) tubing was grafted with hyaluronic acid and dextran. Surfaces were characterized for the presence of the grafted layer using ellipsometry, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Persistence of the surface layer was maintained for up to 5 days of continuous exposure to shear flow using a Chandler loop apparatus. The Chandler loop method was used to study human whole blood activation activity. Whole blood aggregometry and flow cytometry measures of CD18, CD62L, CD62P, Annexin V and myeloperoxidase performed on blood samples exposed to the tubing for up to three hours were complemented by scanning electron microscopy (SEM) analysis of adherent cells and state of activation. In these studies commercial hospital products and uncoated PVC and PU tubes were used as controls. We found that hyaluranized PU and PVC conferred the greatest resistance to blood activation and that dextranization of the PU and PU tubing also provided significant diminution of the bioresponses measured. Based on our findings, we suggest that surface coating with hyaluronic acid or dextran acts as a potent shield from blood cellular activation during forms of extracorporeal circulation.

  13. Application of laws, policies, and guidance from the United States and Canada to the regulation of food and feed derived from genetically modified crops: interpretation of composition data.

    PubMed

    Price, William D; Underhill, Lynne

    2013-09-04

    With the development of recombinant DNA techniques for genetically modifying plants to exhibit beneficial traits, laws and regulations were adopted to ensure the safety of food and feed derived from such plants. This paper focuses on the regulation of genetically modified (GM) plants in Canada and the United States, with emphasis on the results of the compositional analysis routinely utilized as an indicator of possible unintended effects resulting from genetic modification. This work discusses the mandate of Health Canada and the Canadian Food Inspection Agency as well as the U.S. Food and Drug Administration's approach to regulating food and feed derived from GM plants. This work also addresses how publications by the Organisation for Economic Co-operation and Development and Codex Alimentarius fit, particularly with defining the importance and purpose of compositional analysis. The importance of study design, selection of comparators, use of literature, and commercial variety reference values is also discussed.

  14. An OGA-Resistant Probe Allows Specific Visualization and Accurate Identification of O-GlcNAc-Modified Proteins in Cells.

    PubMed

    Li, Jing; Wang, Jiajia; Wen, Liuqing; Zhu, He; Li, Shanshan; Huang, Kenneth; Jiang, Kuan; Li, Xu; Ma, Cheng; Qu, Jingyao; Parameswaran, Aishwarya; Song, Jing; Zhao, Wei; Wang, Peng George

    2016-11-18

    O-linked β-N-acetyl-glucosamine (O-GlcNAc) is an essential and ubiquitous post-translational modification present in nucleic and cytoplasmic proteins of multicellular eukaryotes. The metabolic chemical probes such as GlcNAc or GalNAc analogues bearing ketone or azide handles, in conjunction with bioorthogonal reactions, provide a powerful approach for detecting and identifying this modification. However, these chemical probes either enter multiple glycosylation pathways or have low labeling efficiency. Therefore, selective and potent probes are needed to assess this modification. We report here the development of a novel probe, 1,3,6-tri-O-acetyl-2-azidoacetamido-2,4-dideoxy-d-glucopyranose (Ac34dGlcNAz), that can be processed by the GalNAc salvage pathway and transferred by O-GlcNAc transferase (OGT) to O-GlcNAc proteins. Due to the absence of a hydroxyl group at C4, this probe is less incorporated into α/β 4-GlcNAc or GalNAc containing glycoconjugates. Furthermore, the O-4dGlcNAz modification was resistant to the hydrolysis of O-GlcNAcase (OGA), which greatly enhanced the efficiency of incorporation for O-GlcNAcylation. Combined with a click reaction, Ac34dGlcNAz allowed the selective visualization of O-GlcNAc in cells and accurate identification of O-GlcNAc-modified proteins with LC-MS/MS. This probe represents a more potent and selective tool in tracking, capturing, and identifying O-GlcNAc-modified proteins in cells and cell lysates.

  15. Novel Swelling-Resistant Sodium Alginate Membrane Branching Modified by Glycogen for Highly Aqueous Ethanol Solution Pervaporation.

    PubMed

    Ji, Chen-Hao; Xue, Shuang-Mei; Xu, Zhen-Liang

    2016-10-12

    A novel carbohydrate chain cross-linking method of sodium alginate (SA) is proposed in which glycogen with the branched-chain structure is utilized to cross-link with SA matrix by the bridging of glutaraldehyde (GA). The active layer of SA composite ceramic membrane modified by glycogen and GA for pervaporation (PV) demonstrates great advantages. The branched structure increases the chain density of the active layer, which compresses the free volume between the carbohydrate chains of SA. Large amounts of hydroxyl groups are consumed during the reaction with GA, which reduces the hydrogen bond formation between water molecules and the polysaccharide matrix. The two factors benefit the active layer with great improvement in swelling resistance, promoting the potential of the active layer for the dehydration of an ethanol-water solution containing high water content. Meanwhile, the modified active layer is loaded on the rigid α-Al2O3 ceramic membrane by dip-coating method with the enhancement of anti-deformation and controllable thickness of the active layer. Characterization techniques such as SEM, AFM, XRD, FTIR, XPS, and water contact angle are utilized to observe the composite structure and surface morphology of the composite membrane, to probe the free volume variation, and to determine the chemical composition and hydrophilicity difference of the active layer caused by the different glycogen additive amounts. The membrane containing 3% glycogen in the selective layer demonstrates the flux at 1250 g m(-2) h(-1) coupled with the separation factor of 187 in the 25 wt % water content feed solution at the operating temperature of 75 °C, reflecting superior pervaporation processing capacity compared with the general organic PV membranes in the same condition.

  16. TRACKING GENE FLOW FROM A GENETICALLY MODIFIED CREEPING BENTGRASS -- METHODS, MEASURES AND LESSONS LEARNED

    EPA Science Inventory

    Creeping bentgrass (CBG) expressing an engineered gene for resistance to glyphosate herbicide is one of the first genetically modified (GM) perennial crops to undergo regulatory review for commercial release by the US Department of Agriculture Animal Plant Health and Inspection S...

  17. Engineering of benzylglucosinolate in tobacco provides proof-of-concept for dead-end trap crops genetically modified to attract Plutella xylostella (diamondback moth).

    PubMed

    Møldrup, Morten E; Geu-Flores, Fernando; de Vos, Martin; Olsen, Carl E; Sun, Joel; Jander, Georg; Halkier, Barbara A

    2012-05-01

    Glucosinolates are biologically active natural products characteristic of crucifers, including oilseed rape, cabbage vegetables and the model plant Arabidopsis thaliana. Crucifer-specialist insect herbivores, like the economically important pest Plutella xylostella (diamondback moth), frequently use glucosinolates as oviposition stimuli. This suggests that the transfer of a glucosinolate biosynthetic pathway to a non-crucifer would stimulate oviposition on an otherwise non-attractive plant. Here, we demonstrate that stable genetic transfer of the six-step benzylglucosinolate pathway from A. thaliana to Nicotiana tabacum (tobacco) results in the production of benzylglucosinolate without causing morphological alterations. Benzylglucosinolate-producing tobacco plants were more attractive for oviposition by female P. xylostella moths than wild-type tobacco plants. As newly hatched P. xylostella larvae were unable to survive on tobacco, these results represent a proof-of-concept strategy for rendering non-host plants attractive for oviposition by specialist herbivores with the long-term goal of generating efficient dead-end trap crops for agriculturally important pests.

  18. Phospholipid-modified PEI-based nanocarriers for in vivo siRNA therapeutics against multidrug-resistant tumors.

    PubMed

    Essex, S; Navarro, G; Sabhachandani, P; Chordia, A; Trivedi, M; Movassaghian, S; Torchilin, V P

    2015-03-01

    Multidrug resistance (MDR) mediated by P-glycoprotein overexpression in solid tumors is a major factor in the failure of many forms of chemotherapy. Here we evaluated phospholipid-modified, low-molecular-weight polyethylenimine (DOPE-PEI) nanocarriers for intravenous delivery of anti-P-pg siRNA to tumors with the final goal of modulating MDR in breast cancer. First, we studied the biodistribution of DOPE-PEI nanocarriers and the effect of PEG coating in a subcutaneous breast tumor model. Four hours postinjection, PEGylated carriers showed an 8% injected dose (ID) accumulation in solid tumor via the enhanced permeability and retention effect and 22% ID in serum due to a prolonged, PEG-mediated circulation. Second, we established the therapeutic efficacy and safety of DOPE-PEI/siRNA-mediated P-gp downregulation in combination with doxorubicin (Dox) chemotherapy in MCF-7/MDR xenografts. Weekly injection of siRNA nanopreparations and Dox for up to 5 weeks sensitized the tumors to otherwise non-effective doses of Dox and decreased the tumor volume by threefold vs controls. This therapeutic improvement in response to Dox was attributed to the significant, sequence-specific P-gp downregulation in excised tumors mediated by the DOPE-PEI formulations.

  19. Improved detection of microbial risk of releasing genetically modified bacteria in soil by using massive sequencing and antibiotic resistance selection.

    PubMed

    Han, Il; Lee, Tae Kwon; Han, Jungmin; Doan, Tuan Van; Kim, Seong Bo; Park, Joonhong

    2012-08-15

    High-throughput 16S rRNA gene-targeted pyrosequencing was used with commonly used risk assessment techniques to evaluate the potential microbial risk in soil after inoculating genetically modified (GM) Corynebacterium glutamicum. To verify the risk, reference experiments were conducted in parallel using well-defined and frequently used GM Escherichia coli and wild-type strains. The viable cell count showed that the number of GM bacteria in the soil was reduced to below the detection limit within 10 days, while the molecular indicator for GM plasmids was detected throughout the experiment by using quantitative real-time polymerase chain reactions. Subsequent pyrosequencing showed an insignificant influence of the GM bacteria and/or their GM plasmids on the structure of the soil bacterial community this was similar to non-GM wild-type strains. However, pyrosequencing combined with kanamycin-resistant bacteria selection uncovered a potential risk of GM bacteria on the soil bacterial community and pathogens. The results of the improved methodology showed that the microbial risk attributable to GM C. glutamicum was relatively lower than that attributable to the reference GM E. coli.

  20. Persistent Overexpression of Phosphoglycerate Mutase, a Glycolytic Enzyme, Modifies Energy Metabolism and Reduces Stress Resistance of Heart in Mice

    PubMed Central

    Shioi, Tetsuo; Kato, Takao; Inuzuka, Yasutaka; Kawashima, Tsuneaki; Tamaki, Yodo; Kawamoto, Akira; Tanada, Yohei; Iwanaga, Yoshitaka; Narazaki, Michiko; Matsuda, Tetsuya; Adachi, Souichi; Soga, Tomoyoshi; Takemura, Genzou; Kondoh, Hiroshi; Kita, Toru; Kimura, Takeshi

    2013-01-01

    Background Heart failure is associated with changes in cardiac energy metabolism. Glucose metabolism in particular is thought to be important in the pathogenesis of heart failure. We examined the effects of persistent overexpression of phosphoglycerate mutase 2 (Pgam2), a glycolytic enzyme, on cardiac energy metabolism and function. Methods and Results Transgenic mice constitutively overexpressing Pgam2 in a heart-specific manner were generated, and cardiac energy metabolism and function were analyzed. Cardiac function at rest was normal. The uptake of analogs of glucose or fatty acids and the phosphocreatine/βATP ratio at rest were normal. A comprehensive metabolomic analysis revealed an increase in the levels of a few metabolites immediately upstream and downstream of Pgam2 in the glycolytic pathway, whereas the levels of metabolites in the initial few steps of glycolysis and lactate remained unchanged. The levels of metabolites in the tricarboxylic acid (TCA) cycle were altered. The capacity for respiration by isolated mitochondria in vitro was decreased, and that for the generation of reactive oxygen species (ROS) in vitro was increased. Impaired cardiac function was observed in response to dobutamine. Mice developed systolic dysfunction upon pressure overload. Conclusions Constitutive overexpression of Pgam2 modified energy metabolism and reduced stress resistance of heart in mice. PMID:23951293

  1. GM crops and the rat digestive tract: a critical review.

    PubMed

    Zdziarski, I M; Edwards, J W; Carman, J A; Haynes, J I

    2014-12-01

    The aim of this review is to examine the relationship between genetically modified (GM) crops and health, based on histopathological investigations of the digestive tract in rats. We reviewed published long-term feeding studies of crops containing one or more of three specific traits: herbicide tolerance via the EPSPS gene and insect resistance via cry1Ab or cry3Bb1 genes. These genes are commonly found in commercialised GM crops. Our search found 21 studies for nine (19%) out of the 47 crops approved for human and/or animal consumption. We could find no studies on the other 38 (81%) approved crops. Fourteen out of the 21 studies (67%) were general health assessments of the GM crop on rat health. Most of these studies (76%) were performed after the crop had been approved for human and/or animal consumption, with half of these being published at least nine years after approval. Our review also discovered an inconsistency in methodology and a lack of defined criteria for outcomes that would be considered toxicologically or pathologically significant. In addition, there was a lack of transparency in the methods and results, which made comparisons between the studies difficult. The evidence reviewed here demonstrates an incomplete picture regarding the toxicity (and safety) of GM products consumed by humans and animals. Therefore, each GM product should be assessed on merit, with appropriate studies performed to indicate the level of safety associated with them. Detailed guidelines should be developed which will allow for the generation of comparable and reproducible studies. This will establish a foundation for evidence-based guidelines, to better determine if GM food is safe for human and animal consumption.

  2. Sunflower crop

    SciTech Connect

    Beard, B.H.

    1981-05-01

    A review of the sunflower as a major commercial crop, including its history, cultivation, hybridization and uses. It is grown principally for its oil which is high in polyunsaturated fatty acids and used in a variety of foods. Recently it has been tested in diesel engines and a high protein meal is produced from the seed residues.

  3. Transcriptional analysis of susceptible and resistant European corn borer strains and their response to Cry1F protoxin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of insect resistance to pesticides and biological toxins expressed by genetically modified crop plants is a serious threat to sustainable agricultural production. One of the central goals of insect resistance management (IRM) is to understand the evolution and adaptation of pest inse...

  4. One-year experience with modified BD GeneOhm MRSA assay for detection of methicillin-resistant Staphylococcus aureus from pooled nasal, skin, and throat samples.

    PubMed

    Svent-Kucina, Natasa; Pirs, Mateja; Mueller-Premru, Manica; Cvitkovic-Spik, Vesna; Kofol, Romina; Seme, Katja

    2009-02-01

    We report our 1-year experience with modified GeneOhm MRSA assay (formerly IDI-MRSA) for pooled surveillance specimens in low methicillin-resistant Staphylococcus aureus (MRSA) prevalence clinical setting. We have successfully modified the GeneOhm MRSA assay protocol during the specimen preparation step by adding an extra washing step followed by pooling of up to 3 samples per patient (nose, skin, with or without throat) at the lysis step. The sensitivity of the modified assay compared with conventional cultivation was 94.3%, specificity 99.2%, negative predictive value 99.2%, and positive predictive value 94.3%. The modified test is reliable and performed well compared with conventional culture methods in our clinical setting with low-level prevalence of MRSA colonization. Our findings support the use of pooling of the patients samples as a cost-effective way of screening for MRSA colonization.

  5. A comparative analysis of media reporting of perceived risks and benefits of genetically modified crops and foods in Kenyan and international newspapers.

    PubMed

    DeRosier, Christopher; Sulemana, Iddisah; James, Harvey S; Valdivia, Corinne; Folk, William; Smith, Randall D

    2015-07-01

    We empirically examine the reporting on biotechnology in Kenyan and international newspapers between 2010 and early 2014. We identify news articles that reported on biotechnology and analyze their use of words to determine whether there is a balance in the reporting of perceived risks and benefits. We also consider how the sources used in news articles and how the publication of the Séralini study of rats fed genetically modified maize affect the balance of reporting of perceived risks and benefits. We find that in Kenyan news reporting, more articles mention perceived benefits than risks, but when risks are mentioned, new articles contain more references to risks than to benefits. We also find that sources affect the reporting of perceived risks and benefits and that the Séralini study increased the likelihood that perceived risks are reported in Kenyan news reporting, but not in international newspapers.

  6. Biotechnology Towards Energy Crops.

    PubMed

    Margaritopoulou, Theoni; Roka, Loukia; Alexopoulou, Efi; Christou, Myrsini; Rigas, Stamatis; Haralampidis, Kosmas; Milioni, Dimitra

    2016-03-01

    New crops are gradually establishing along with cultivation systems to reduce reliance on depleting fossil fuel reserves and sustain better adaptation to climate change. These biological assets could be efficiently exploited as bioenergy feedstocks. Bioenergy crops are versatile renewable sources with the potential to alternatively contribute on a daily basis towards the coverage of modern society's energy demands. Biotechnology may facilitate the breeding of elite energy crop genotypes, better suited for bio-processing and subsequent use that will improve efficiency, further reduce costs, and enhance the environmental benefits of biofuels. Innovative molecular techniques may improve a broad range of important features including biomass yield, product quality and resistance to biotic factors like pests or microbial diseases or environmental cues such as drought, salinity, freezing injury or heat shock. The current review intends to assess the capacity of biotechnological applications to develop a beneficial bioenergy pipeline extending from feedstock development to sustainable biofuel production and provide examples of the current state of the art on future energy crops.

  7. Belowground environmental effects of transgenic crops: a soil microbial perspective.

    PubMed

    Turrini, Alessandra; Sbrana, Cristiana; Giovannetti, Manuela

    2015-04-01

    Experimental studies investigated the effects of transgenic crops on the structure, function and diversity of soil and rhizosphere microbial communities playing key roles in belowground environments. Here we review available data on direct, indirect and pleiotropic effects of engineered plants on soil microbiota, considering both the technology and the genetic construct utilized. Plants modified to express phytopathogen/phytoparasite resistance, or traits beneficial to food industries and consumers, differentially affected soil microorganisms depending on transformation events, experimental conditions and taxa analyzed. Future studies should address the development of harmonized methodologies by taking into account the complex interactions governing soil life.

  8. Globalization’s unexpected impact on soybean production in South America: linkages between preferences for non-genetically modified crops, eco-certifications, and land use

    NASA Astrophysics Data System (ADS)

    Garrett, Rachael D.; Rueda, Ximena; Lambin, Eric F.

    2013-12-01

    The land use impacts of globalization and of increasing global food and fuel demand depend on the trade relationships that emerge between consuming and producing countries. In the case of soybean production, increasing trade between South American farmers and consumers in Asia and Europe has facilitated soybean expansion in the Amazon, Chaco, and Cerrado biomes. While these telecouplings have been well documented, there is little understanding of how quality preferences influence trade patterns and supply chains, incentivizing or discouraging particular land use practices. In this study we provide empirical evidence that Brazil’s continued production of non-genetically modified (GM) soybeans has increased its competitive advantage in European countries with preferences against GM foods. Brazil’s strong trade relationship with European consumers has facilitated an upgrading of the soybean supply chain. Upgraded soybean supply chains create new conservation opportunities by allowing farmers to differentiate their products based on environmental quality in order to access premiums in niche markets in Europe. These interactions between GM preferences, trade flows, and supply chain structure help to explain why Brazilian soybean farmers have adopted environmental certification programs on a larger scale than Argentinian, Bolivian, Paraguayan, and Uruguayan soybean producers.

  9. Innate and Introduced Resistance Traits in Genetically Modified Aspen Trees and Their Effect on Leaf Beetle Feeding

    PubMed Central

    Hjältén, Joakim; Axelsson, E. Petter; Julkunen-Tiitto, Riitta; Wennström, Anders; Pilate, Gilles

    2013-01-01

    Genetic modifications of trees may provide many benefits, e.g. increase production, and mitigate climate change and herbivore impacts on forests. However, genetic modifications sometimes result in unintended effects on innate traits involved in plant-herbivore interactions. The importance of intentional changes in plant defence relative to unintentional changes and the natural variation among clones used in forestry has not been evaluated. By a combination of biochemical measurements and bioassays we investigated if insect feeding on GM aspens is more affected by intentional (induction Bt toxins) than of unintentional, non-target changes or clonal differences in innate plant defence. We used two hybrid wildtype clones (Populus tremula x P. tremuloides and Populus tremula x P. alba) of aspen that have been genetically modified for 1) insect resistance (two Bt lines) or 2) reduced lignin properties (two lines COMT and CAD), respectively. Our measurements of biochemical properties suggest that unintended changes by GM modifications (occurring due to events in the transformation process) in innate plant defence (phenolic compounds) were generally smaller but fundamentally different than differences seen among different wildtype clones (e.g. quantitative and qualitative, respectively). However, neither clonal differences between the two wildtype clones nor unintended changes in phytochemistry influenced consumption by the leaf beetle (Phratora vitellinae). By contrast, Bt induction had a strong direct intended effect as well as a post experiment effect on leaf beetle consumption. The latter suggested lasting reduction of beetle fitness following Bt exposure that is likely due to intestinal damage suffered by the initial Bt exposure. We conclude that Bt induction clearly have intended effects on a target species. Furthermore, the effect of unintended changes in innate plant defence traits, when they occur, are context dependent and have in comparison to Bt induction

  10. Evaluation of detection methods for genetically modified traits in genotypes resistant to European corn borer and herbicides.

    PubMed

    Ma, B L; Subedi, K; Evenson, L; Stewart, G

    2005-01-01

    Detection of genetically modified (GM) traits in corn (Zea mays L.) is urgently needed for preservation of genetic identity and marketing GM products. A laboratory study was conducted to evaluate the efficiency, accuracy, and reliability of different analytical methods to detect GM traits in corn. Samples with known fractions of GM concentrations (Bacillus thuringiensis [Bt], Liberty Link [LL] and stacked [Bt/LL] genes) from commercial seed companies and those derived from yellow kernels in a white corn ear, outcrossed by pollen of neighboring Bt hybrid, were tested by lateral flow quick test kits and by enzyme-linked immunosorbent assay (ELISA)-based test strips purchased from different companies. Liberty Link hybrids are resistant to glufosinate (Liberty or Basta) herbicides, whereas Bt corn is developed for the control of European corn borer (Ostrinia nubilalis). Selected samples of GM concentrations were also tested in a commercial laboratory using DNA-based polymerase chain reaction (PCR) test. The results demonstrated that qualitative lateral flow quick tests could detect samples containing 1% or higher Bt and 2% or higher LL concentrations within the recommended time limit of the test. Faint test lines for samples containing 0.5 to 1% Bt or 1 to 2% LL concentrations appeared if samples remained in the test cup overnight. ELISA test strips detected the Bt content semiquantitatively in the range of 0.5 to 2.0%. Grain samples derived from non-Bt corn outcrossed by neighboring Bt pollen had usually lower GM concentrations than commercial GM seed samples. Both ELISA- and DNA-based PCR tests distinguished samples with GM concentrations between 0.1 to 0.5%, but the precision of quantification at this range was very low and results were highly inconsistent.

  11. Further Modification of the Modified Hodge Test for Detecting Metallo-β-Lactamase-Producing Carbapenem-Resistant Enterobacteriaceae

    PubMed Central

    Kim, Hyun-Ki; Park, Jeong Su; Sung, Heungsup

    2015-01-01

    Background The modified Hodge test (MHT) was designed to detect carbapenemase-producing Enterobacteriaceae (CPE). This study evaluated variables to improve the performance of MHT. Methods Carbapenem-resistant Enterobacteriaceae isolated from November 2010 to March 2013 at the Asan Medical Center, were evaluated, including 33 metallo-β-lactamase (MBL) producers and 103 non-CPEs. MHT was performed by using two carbapenem disks (ertapenem and meropenem; Becton Dickinson, USA), three media (Mueller-Hinton agar (MHA), MacConkey agar (MAC), and zinc-enriched MHA), and two inoculums (0.5-McFarland [McF] suspension and a 10-fold dilution of it.) PCR was performed to detect β-lactamase genes of the MBL, AmpC, and CTX-M types. Results The sensitivity of MHT for detecting New Delhi metallo-β-lactamase (NDM) producers was highest using ertapenem and 0.5-McF, 52.0% on MHA and 68.0% on MAC, respectively. NDM-producing Klebsiella pneumoniae (NDMKP) were detected with higher sensitivity on MAC (78.6%) vs. MHA (28.6%) (P=0.016), but VIM-producing Enterobacter, Citrobacter, and Serratia were detected with higher sensitivity on MHA (78.5%) vs. MAC (14.3%) (P=0.004). MBL producers were consistently identified with lower sensitivity using meropenem vs. ertapenem, 39.4% vs. 60.6% (P=0.0156), respectively. The effects of zinc and inoculum size were insignificant. Enterobacter aerogenes producing unspecified AmpC frequently demonstrated false positives, 66.7% with ertapenem and 22.2% with meropenem. Conclusions The MHT should be adjusted for the local distribution of species and the carbapenemase type of MBL producers. MAC and ertapenem are preferable for assessing NDMKP, but MHA is better for VIM. Laboratory physicians should be aware of the limited sensitivity of MHT and its relatively high false-positive rate. PMID:25932437

  12. Genetically modified crops in a 10-generation feeding trial on Japanese quails--Evaluation of its influence on birds' performance and body composition.

    PubMed

    Sartowska, K E; Korwin-Kossakowska, A; Sender, G

    2015-12-01

    The effect of genetically modified (GM) feed components comprising soya bean meal and maize on the performance indices (reproduction, survival rate, growth, egg production, relative weight of chosen internal organs, and basic chemical composition of breast muscle and egg yolk) of Japanese quails was investigated during a 10-generation trial. A total number of 8,438 healthy quail chicks were used in the course of the trial. In each generation, birds were maintained in 3 experimental groups differing in the main feed components, i.e. 1) GM soya (Roundup Ready) and non-GM maize, 2) GM maize (MON810) and non-GM soya, and 3) non-GM soya and maize. The different feeds used did not influence any of the biological hatch indices, survival rate, or BW of young or adult quails. With regard to egg-laying performance, the GM maize group showed a better laying percentage and a higher egg mass production compared to the other groups; the GM soya group showed reduced average egg mass compared to the other groups, whereas the overall egg production level was the same as in the control group. Results showed a higher relative weight of breast muscle and gizzard in birds fed GM maize compared to the control group, whereas live BW and the relative weights of liver and heart were not different among groups. Meat from the GM soya group showed higher protein and lower fat levels compared to the control group. In the case of egg yolk, its chemical composition in the experimental groups did not differ from the control group. Even though some differences were found among the feeding groups, none could be judged as a negative influence of GM maize or GM soya in feed on the birds or final consumer products over 10 generations of Japanese quails.

  13. Characterizing Nitrous Oxide (N2O) Emissions over a Wheat-based Cropping System in the Northwest United States Using the Modified Bowen Ratio Technique and Static Chambers

    NASA Astrophysics Data System (ADS)

    Waldo, Sarah; Kostyanovsky, Kirill; O'Keeffe, Patrick; Pressley, Shelley; Huggins, Dave; Stockle, Claudio; Lamb, Brian

    2015-04-01

    Nitrous oxide (N2O) is a potent greenhouse gas and ozone depleting substance. Agricultural soils are the primary source of N2O, which is created as a by-product of soil microbial processes. The production and emission of N2O is characterized by high spatial and temporal variability, or "hot spots" and "hot moments". These behaviors, along with limitations in instrument sensitivity to N2O, are challenges in characterizing emissions. Many studies have monitored N2O emissions using either static chambers or micrometeorological measurements or the two methods together. The two techniques are complementary: chamber methods have a lower detection limit and are more reliable as their operation does not depend on atmospheric conditions, but may not capture spatial variability even with multiple chambers. Tower-based methods are subject to relatively high data loss due to non-ideal conditions and to less sensitive detection limits, but have a larger measurement footprint and can characterize field-scale emissions. This study aims to characterize a long-term, field-scale N2O budget over two winter wheat fields located in the Inland Pacific Northwest of the United States, both in terms of an annual emission budget and in terms of understanding what causes hot moments. We combined continuous measurements of N2O emissions from a system of sixteen automated, static chambers with tower-based measurements of N2O fluxes. We used the modified Bowen ratio (MBR) technique with temperature as a tracer. Preliminary results indicate that freeze-thaw cycles in the winter make up a higher percentage of annual emissions than previously thought. Furthermore, comparison of the chamber results to the tower-based measurements imply that the chambers may be underestimating field-scale N2O fluxes because they are not adequately capturing hot spots of emissions. We are conducting ongoing work on how to integrate the two measurement techniques, as well as how the empirical measurements compare with

  14. Public Acceptance of Plant Biotechnology and GM Crops.

    PubMed

    Lucht, Jan M

    2015-07-30

    A wide gap exists between the rapid acceptance of genetically modified (GM) crops for cultivation by farmers in many countries and in the global markets for food and feed, and the often-limited acceptance by consumers. This review contrasts the advances of practical applications of agricultural biotechnology with the divergent paths-also affecting the development of virus resistant transgenic crops-of political and regulatory frameworks for GM crops and food in different parts of the world. These have also shaped the different opinions of consumers. Important factors influencing consumer's attitudes are the perception of risks and benefits, knowledge and trust, and personal values. Recent political and societal developments show a hardening of the negative environment for agricultural biotechnology in Europe, a growing discussion-including calls for labeling of GM food-in the USA, and a careful development in China towards a possible authorization of GM rice that takes the societal discussions into account. New breeding techniques address some consumers' concerns with transgenic crops, but it is not clear yet how consumers' attitudes towards them will develop. Discussions about agriculture would be more productive, if they would focus less on technologies, but on common aims and underlying values.

  15. Intergrated palmer amaranth management in glufosinate-resistant cotton: I. Soil-inversion, high-residue cover crops and herbicide regimes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Amaranthus control in cotton can be difficult with the loss of glyphosate efficacy, especially in conservation tillage cropping systems. Research was conduction from 2006 to 2008 at EV Smith Research Center, Shorter, Alabama, to determine the level of glyphosate susceptible amaranthus control provi...

  16. 75 FR 59057 - Common Crop Insurance Regulations, Cotton Crop Insurance Provisions and Macadamia Nut Crop...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-27

    ... Provisions and Macadamia Nut Crop Insurance Provisions; Correction AGENCY: Federal Crop Insurance Corporation... Provisions and applicable Crop Provisions, including the Cotton Crop Insurance Provisions. In addition, FCIC revised various Crop Provisions, including the Macadamia Nut Crop Insurance Provisions, to...

  17. Effects of GM crops on non-target organisms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop genetically engineered to provide resistance to specific groups of insect pests have been adopted by millions of growers throughout the world. GM crops have become important tools in crop production and protection in many countries and contribute significantly to overall IPM programs. There, ...

  18. Environmental impacts of genetically modified plants: A review.

    PubMed

    Tsatsakis, Aristidis M; Nawaz, Muhammad Amjad; Kouretas, Demetrios; Balias, Georgios; Savolainen, Kai; Tutelyan, Victor A; Golokhvast, Kirill S; Lee, Jeong Dong; Yang, Seung Hwan; Chung, Gyuhwa

    2017-03-27

    Powerful scientific techniques have caused dramatic expansion of genetically modified crops leading to altered agricultural practices posing direct and indirect environmental implications. Despite the enhanced yield potential, risks and biosafety concerns associated with such GM crops are the fundamental issues to be addressed. An increasing interest can be noted among the researchers and policy makers in exploring unintended effects of transgenes associated with gene flow, flow of naked DNA, weediness and chemical toxicity. The current state of knowledge reveals that GM crops impart damaging impacts on the environment such as modification in crop pervasiveness or invasiveness, the emergence of herbicide and insecticide tolerance, transgene stacking and disturbed biodiversity, but these impacts require a more in-depth view and critical research so as to unveil further facts. Most of the reviewed scientific resources provide similar conclusions and currently there is an insufficient amount of data available and up until today, the consumption of GM plant products are safe for consumption to a greater extent with few exceptions. This paper updates the undesirable impacts of GM crops and their products on target and non-target species and attempts to shed light on the emerging challenges and threats associated with it. Underpinning research also realizes the influence of GM crops on a disturbance in biodiversity, development of resistance and evolution slightly resembles with the effects of non-GM cultivation. Future prospects are also discussed.

  19. Simulating Stochastic Crop Management in Cropping Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction -- Crop simulation models are uniquely suitable for examining long term crop responses to environmental variability due to changes in climate or other factors. Long-term studies typically emphasize variability related to weather conditions; certain weather-dependent cropping practices m...

  20. Singly modified amikacin and tobramycin derivatives show increased rRNA A-site binding and higher potency against resistant bacteria.

    PubMed

    Fair, Richard J; McCoy, Lisa S; Hensler, Mary E; Aguilar, Bernice; Nizet, Victor; Tor, Yitzhak

    2014-09-01

    Semisynthetic derivatives of the clinically useful aminoglycosides tobramycin and amikacin were prepared by selectively modifying their 6'' positions with a variety of hydrogen bond donors and acceptors. Their binding to the rRNA A-site was probed using an in vitro FRET-based assay, and their antibacterial activities against several resistant strains (e.g., Pseudomonas aeruginosa, Klebsiella pneumonia, MRSA) were quantified by determining minimum inhibitory concentrations (MICs). The most potent derivatives were evaluated for their eukaryotic cytotoxicity. Most analogues displayed higher affinity for the bacterial A-site than the parent compounds. Although most tobramycin analogues exhibited no improvement in antibacterial activity, several amikacin analogues showed potent and broad-spectrum antibacterial activity against resistant bacteria. Derivatives tested for eukaryotic cytotoxicity exhibited minimal toxicity, similar to the parent compounds.

  1. Phosphoethanolamine Transferase LptA in Haemophilus ducreyi Modifies Lipid A and Contributes to Human Defensin Resistance In Vitro.

    PubMed

    Trombley, Michael P; Post, Deborah M B; Rinker, Sherri D; Reinders, Lorri M; Fortney, Kate R; Zwickl, Beth W; Janowicz, Diane M; Baye, Fitsum M; Katz, Barry P; Spinola, Stanley M; Bauer, Margaret E

    2015-01-01

    Haemophilus ducreyi resists the cytotoxic effects of human antimicrobial peptides (APs), including α-defensins, β-defensins, and the cathelicidin LL-37. Resistance to LL-37, mediated by the sensitive to antimicrobial peptide (Sap) transporter, is required for H. ducreyi virulence in humans. Cationic APs are attracted to the negatively charged bacterial cell surface. In other gram-negative bacteria, modification of lipopolysaccharide or lipooligosaccharide (LOS) by the addition of positively charged moieties, such as phosphoethanolamine (PEA), confers AP resistance by means of electrostatic repulsion. H. ducreyi LOS has PEA modifications at two sites, and we identified three genes (lptA, ptdA, and ptdB) in H. ducreyi with homology to a family of bacterial PEA transferases. We generated non-polar, unmarked mutants with deletions in one, two, or all three putative PEA transferase genes. The triple mutant was significantly more susceptible to both α- and β-defensins; complementation of all three genes restored parental levels of AP resistance. Deletion of all three PEA transferase genes also resulted in a significant increase in the negativity of the mutant cell surface. Mass spectrometric analysis revealed that LptA was required for PEA modification of lipid A; PtdA and PtdB did not affect PEA modification of LOS. In human inoculation experiments, the triple mutant was as virulent as its parent strain. While this is the first identified mechanism of resistance to α-defensins in H. ducreyi, our in vivo data suggest that resistance to cathelicidin LL-37 may be more important than defensin resistance to H. ducreyi pathogenesis.

  2. Phosphoethanolamine Transferase LptA in Haemophilus ducreyi Modifies Lipid A and Contributes to Human Defensin Resistance In Vitro

    PubMed Central

    Trombley, Michael P.; Post, Deborah M. B.; Rinker, Sherri D.; Reinders, Lorri M.; Fortney, Kate R.; Zwickl, Beth W.; Janowicz, Diane M.; Baye, Fitsum M.; Katz, Barry P.; Spinola, Stanley M.; Bauer, Margaret E.

    2015-01-01

    Haemophilus ducreyi resists the cytotoxic effects of human antimicrobial peptides (APs), including α-defensins, β-defensins, and the cathelicidin LL-37. Resistance to LL-37, mediated by the sensitive to antimicrobial peptide (Sap) transporter, is required for H. ducreyi virulence in humans. Cationic APs are attracted to the negatively charged bacterial cell surface. In other gram-negative bacteria, modification of lipopolysaccharide or lipooligosaccharide (LOS) by the addition of positively charged moieties, such as phosphoethanolamine (PEA), confers AP resistance by means of electrostatic repulsion. H. ducreyi LOS has PEA modifications at two sites, and we identified three genes (lptA, ptdA, and ptdB) in H. ducreyi with homology to a family of bacterial PEA transferases. We generated non-polar, unmarked mutants with deletions in one, two, or all three putative PEA transferase genes. The triple mutant was significantly more susceptible to both α- and β-defensins; complementation of all three genes restored parental levels of AP resistance. Deletion of all three PEA transferase genes also resulted in a significant increase in the negativity of the mutant cell surface. Mass spectrometric analysis revealed that LptA was required for PEA modification of lipid A; PtdA and PtdB did not affect PEA modification of LOS. In human inoculation experiments, the triple mutant was as virulent as its parent strain. While this is the first identified mechanism of resistance to α-defensins in H. ducreyi, our in vivo data suggest that resistance to cathelicidin LL-37 may be more important than defensin resistance to H. ducreyi pathogenesis. PMID:25902140

  3. Controlled-release of Bacillus thurigiensis formulations encapsulated in light-resistant colloidosomal microcapsules for the management of lepidopteran pests of Brassica crops

    PubMed Central

    Bashir, Oumar; Lemoyne, Pierre

    2016-01-01

    Bacillus thuringiensis (B. t.) based formulations have been widely used to control lepidopteran pests in agriculture and forestry. One of their weaknesses is their short residual activity when sprayed in the field. Using Pickering emulsions, mixtures of spores and crystals from three B. t. serovars were successfully encapsulated in colloïdosomal microparticles (50 μm) using innocuous chemicals (acrylic particles, sunflower oil, iron oxide nanoparticles, ethanol and water). A pH trigger mechanism was incorporated within the particles so that B. t. release occurred only at pH > 8.5 which corresponds to the midgut pH of the target pests. Laboratory assays performed on Trichoplusia ni (T. ni) larvae demonstrated that the microencapsulation process did not impair B. t. bioactivity. The best formulations were field-tested on three key lepidopteran pests that attack Brassica crops, i.e., the imported cabbageworm, the cabbage looper and the diamondback moth. After 12 days, the mean number of larvae was significantly lower in microencapsulated formulations than in a commercial B. t. formulation, and the effect of microencapsulated formulations was comparable to a chemical pesticide (lambda-cyhalothrin). Therefore, colloïdosomal microcapsule formulations successfully extend the bioactivity of B. t. for the management of lepidopteran pests of Brassica crops. PMID:27761325

  4. Controlled-release of Bacillus thurigiensis formulations encapsulated in light-resistant colloidosomal microcapsules for the management of lepidopteran pests of Brassica crops.

    PubMed

    Bashir, Oumar; Claverie, Jerome P; Lemoyne, Pierre; Vincent, Charles

    2016-01-01

    Bacillus thuringiensis (B. t.) based formulations have been widely used to control lepidopteran pests in agriculture and forestry. One of their weaknesses is their short residual activity when sprayed in the field. Using Pickering emulsions, mixtures of spores and crystals from three B. t. serovars were successfully encapsulated in colloïdosomal microparticles (50 μm) using innocuous chemicals (acrylic particles, sunflower oil, iron oxide nanoparticles, ethanol and water). A pH trigger mechanism was incorporated within the particles so that B. t. release occurred only at pH > 8.5 which corresponds to the midgut pH of the target pests. Laboratory assays performed on Trichoplusia ni (T. ni) larvae demonstrated that the microencapsulation process did not impair B. t. bioactivity. The best formulations were field-tested on three key lepidopteran pests that attack Brassica crops, i.e., the imported cabbageworm, the cabbage looper and the diamondback moth. After 12 days, the mean number of larvae was significantly lower in microencapsulated formulations than in a commercial B. t. formulation, and the effect of microencapsulated formulations was comparable to a chemical pesticide (lambda-cyhalothrin). Therefore, colloïdosomal microcapsule formulations successfully extend the bioactivity of B. t. for the management of lepidopteran pests of Brassica crops.

  5. Identification of a chitinase modifying protein from Fusarium verticillioides: truncation of a host resistance protein by a fungalysin metalloprotease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chitinase modifying proteins (cmps) are proteases, secreted by fungal pathogens, which truncate the plant class IV chitinases ChitA and ChitB during maize ear rot. Cmp activity has been characterized for Bipolaris zeicola and Stenocarpella maydis, but the identities of the proteases are not known. H...

  6. Evaluation of spring wheat and barley crop calender models for the 1979 crop year

    NASA Technical Reports Server (NTRS)

    Nazare, C. V.; Carnes, J. G. (Principal Investigator)

    1981-01-01

    During the Large Area Crop Inventory Experiment, spring wheat planting date and crop development stage estimates based on historical normals were improved by the use of the Feyerherm planting date and Robertson spring wheat crop calendar models. The Supporting Research Crop Calendar Project element modified the Robertson model to reduce bias at cardinal growth stages within the growing season. These models were tested in 1980 along with a state-of-the-art barley model (Williams) against a ground-truth data set from 49 calendar year 1979 segments in the U.S. Great Plains spring wheat and barley region.

  7. Evolutionary ecology of insect adaptation to Bt crops

    PubMed Central

    Carrière, Yves; Crowder, David W; Tabashnik, Bruce E

    2010-01-01

    Transgenic crops producing Bacillus thuringiensis (Bt) toxins are used worldwide to control major pests of corn and cotton. Development of strategies to delay the evolution of pest resistance to Bt crops requires an understanding of factors affecting responses to natural selection, which include variation in survival on Bt crops, heritability of resistance, and fitness advantages associated with resistance mutations. The two main strategies adopted for delaying resistance are the refuge and pyramid strategies. Both can reduce heritability of resistance, but pyramids can also delay resistance by reducing genetic variation for resistance. Seasonal declines in the concentration of Bt toxins in transgenic cultivars, however, can increase the heritability of resistance. The fitness advantages associated with resistance mutations can be reduced by agronomic practices, including increasing refuge size, manipulating refuges to increase fitness costs, and manipulating Bt cultivars to reduce fitness of resistant individuals. Manipulating costs and fitness of resistant individuals on transgenic insecticidal crops may be especially important for thwarting evolution of resistance in haplodiploid and parthenogenetic pests. Field-evolved resistance to Bt crops in only five pests during the last 14 years suggests that the refuge strategy has successfully delayed resistance, but the accumulation of resistant pests could accelerate. PMID:25567947

  8. Novel reverse osmosis membranes composed of modified PVA/Gum Arabic conjugates: Biofouling mitigation and chlorine resistance enhancement.

    PubMed

    Falath, Wail; Sabir, Aneela; Jacob, Karl I

    2017-01-02

    A novel crosslinked Poly (vinyl alcohol) (PVA) reverse osmosis (RO) thin film membrane conjugated with Gum Arabic (GA) with superb performance and features was synthesized for water desalination. RO membrane desalination parameters, such as hydrophilicity, surface roughness, water permeability, salt rejection, Chlorine resistance and biofouling resistance were evaluated using a dead end RO filtration unit. The incorporation of Pluronic F127 and the conjugation of Gum Arabic improved the overall RO performance of the membranes. This study has shown that the membrane PVA-GA-5 that contains 0.9wt% Gum Arabic provided excellent permeation, salt rejection, Chlorine and biofouling resistance and mechanical strength. The most remarkable result to arise from this research is that the overall RO performance enhancement has been achieved while utilizing PVA/Gum Arabic as a separation layer without the use of a substrate, which eliminates negative effects associated with the use of a substrate like internal concentration polarization.

  9. Reliability of high-content disks and modified broth dilution tests for detecting staphylococcal resistance to the penicillinase-resistant penicillins.

    PubMed Central

    Barry, A L; Jones, R N

    1987-01-01

    In vitro susceptibility tests were performed with 271 isolates of Staphylococcus species (204 Staphylococcus aureus), including 110 strains resistant to the penicillinase-resistant penicillins. Disks containing 5 or 10 micrograms of methicillin, 1 or 4 micrograms of oxacillin, and 1 or 4 micrograms of nafcillin were evaluated. After a full 24 h of incubation at 35 degrees C, tests with 1-microgram oxacillin disks provided optimal results. Use of the more potent oxacillin, nafcillin, or methicillin disks only increased the number of false-susceptible test results. For broth microdilution tests, 2% NaCl should be added to cation-supplemented Mueller-Hinton broth, and MICs should be recorded after a full 24 h at 35 degrees C. Microdilution tests with oxacillin in broth with 2% NaCl were more reliable than similar tests with methicillin. PMID:3499451

  10. Safety assessment and public concerns for genetically modified food products: the Japanese experience.

    PubMed

    Hino, Akihiro

    2002-01-01

    The recombinant DNA (rDNA) technique is expected to bring about great progress in the improvement of breeding technology and the development of new plant varieties showing high quality and high yield, such as those with excellent pest and disease resistance, those with environmental stress tolerance, and so forth. In the United States and Canada, many genetically modified (GM) crop plants were commercialized as early as 1994. In Japan, 35 transgenic crop plants, such as herbicide tolerant soybean, cotton, and canola, and insect-resistant corn, cotton, and potatos, were authorized and considered marketable until April 2001. The general public, however, is not familiar with rDNA technology, and some people seem to feel uncomfortable with biotechnology, frequently because of the difficulty of the technology and lacking of sufficient information. New labeling systems were initiated in April 2001 in Japan to provide information regarding the use of GM crops as raw material.

  11. Cover crop water use

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cover crops are being widely promoted because of soil health benefits. However, semi-arid dryland production systems, chronically short of water for crop production, may not be able to profitably withstand the yield reduction that follows cover crops because of cover crop water use. Some studies sug...

  12. Public Acceptance of Plant Biotechnology and GM Crops

    PubMed Central

    Lucht, Jan M.

    2015-01-01

    A wide gap exists between the rapid acceptance of genetically modified (GM) crops for cultivation by farmers in many countries and in the global markets for food and feed, and the often-limited acceptance by consumers. This review contrasts the advances of practical applications of agricultural biotechnology with the divergent paths—also affecting the development of virus resistant transgenic crops—of political and regulatory frameworks for GM crops and food in different parts of the world. These have also shaped the different opinions of consumers. Important factors influencing consumer’s attitudes are the perception of risks and benefits, knowledge and trust, and personal values. Recent political and societal developments show a hardening of the negative environment for agricultural biotechnology in Europe, a growing discussion—including calls for labeling of GM food—in the USA, and a careful development in China towards a possible authorization of GM rice that takes the societal discussions into account. New breeding techniques address some consumers’ concerns with transgenic crops, but it is not clear yet how consumers’ attitudes towards them will develop. Discussions about agriculture would be more productive, if they would focus less on technologies, but on common aims and underlying values. PMID:26264020

  13. PCSK7 Genotype Modifies Effect of a Weight-Loss Diet on 2-Year Changes of Insulin Resistance: The POUNDS LOST Trial

    PubMed Central

    Huang, Tao; Huang, Jinyan; Qi, Qibin; Li, Yanping; Bray, George A.; Rood, Jennifer; Sacks, Frank M.

    2015-01-01

    OBJECTIVE A common variant rs236918 in the PCSK7 gene has the strongest association with iron homeostasis and is related to insulin resistance. Dietary carbohydrate (CHO) modulates the genetic effect on insulin resistance. We examined whether 2-year weight-loss diets modify the effect of PCSK7 genetic variants on changes in fasting insulin levels and insulin resistance in a randomized, controlled trial. RESEARCH DESIGN AND METHODS Data were analyzed in the Preventing Overweight Using Novel Dietary Strategies (POUNDS LOST) trial, which is a randomized, controlled 2-year weight-loss trial using diets that differed in macronutrient proportions. PCSK7 rs236918 was genotyped in 730 overweight or obese adults (80% whites) in this trial. We assessed the progression in fasting insulin and glucose levels, and insulin resistance by genotypes. RESULTS During the 6-month weight-loss phase, the PCSK7 rs236918 G allele was significantly associated with greater decreases in fasting insulin levels in the high–dietary CHO group (P for interaction = 0.04), while the interaction for changes in HOMA-insulin resistance (HOMA-IR) (P for interaction = 0.06) did not reach significant levels in white subjects. The G allele was significantly associated with a greater decrease in fasting insulin levels and HOMA-IR in response to high dietary CHO levels (P = 0.02 and P = 0.03, respectively). From 6 months to 2 years (weight-regain phase), the interactions became attenuated due to the regaining of weight (P for interactions = 0.08 and 0.06, respectively). In addition, we observed similar and even stronger results in the whole-study samples from the trial. CONCLUSIONS Our data suggest that PCSK7 genotypes may interact with dietary CHO intake on changes in insulin sensitivity in the white Americans. PMID:25504030

  14. The draft genome of whitefly Bemisia tabaci MEAM1, a global crop pest, provides novel insights into virus transmission, host adaptation, and insecticide resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Whiteflies are among the most important agricultural pests. They have a broad range of host plants and exceptional ability to transmit a large number of plant viruses, and can rapidly evolve insecticide resistance. Here we present a high-quality draft genome of the whitefly, Bemisia tabaci. Comparat...

  15. Evolution of New Disease Specificity at a Single Resistance Locus in a Crop-Weed Complex: Reconstitution of the Lr21 Gene in Wheat.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaf-rust resistance gene Lr21, present in modern varieties of hexaploid wheat, originated in goatgrass Aegilops tauschii Coss., the D genome donor of wheat. The goatgrass donor was collected in Iran where it grows as a weed in wheat fields as part of the native agricultural ecosystem. In order to ...

  16. Current trends in Bt crops and their fate on associated microbial community dynamics: a review.

    PubMed

    Singh, Amit Kishore; Dubey, Suresh Kumar

    2016-05-01

    Cry protein expressing insect-resistant trait is mostly deployed to control major devastating pests and minimize reliance on the conventional pesticides. However, the ethical and environmental issues are the major constraints in their acceptance, and consequently, the cultivation of genetically modified (GM) crops has invited intense debate. Since root exudates of Bacillus thuringiensis (Bt) crops harbor the insecticidal protein, there is a growing concern about the release and accumulation of soil-adsorbed Cry proteins and their impact on non-target microorganisms and soil microbial processes. This review pertains to reports from the laboratory studies and field trials to assess the Bt toxin proteins in soil microbes and the processes determining the soil quality in conjunction with the existing hypothesis and molecular approaches to elucidate the risk posed by the GM crops. Ecological perturbations hinder the risk aspect of soil microbiota in response to GM crops. Therefore, extensive research based on in vivo and interpretation of results using high-throughput techniques such as NGS on risk assessment are imperative to evaluate the impact of Bt crops to resolve the controversy related to their commercialization. But more studies are needed on the risk associated with stacked traits. Such studies would strengthen our knowledge about the plant-microbe interactions.

  17. Minimising losses caused by Zucchini yellow mosaic virus in vegetable cucurbit crops in tropical, sub-tropical and Mediterranean environments through cultural methods and host resistance.

    PubMed

    Coutts, B A; Kehoe, M A; Jones, R A C

    2011-08-01

    Between 2006 and 2009, 10 field experiments were done at Kununurra, Carnarvon or Medina in Western Australia (WA) which have tropical, sub-tropical and Mediterranean climates, respectively. These experiments investigated the effectiveness of cultural control measures in limiting ZYMV spread in pumpkin, and single-gene resistance in commercial cultivars of pumpkin, zucchini and cucumber. Melon aphids (Aphis gossypii) colonised field experiments at Kununurra; migrant green peach aphids (Myzus persicae) visited but did not colonise at Carnarvon and Medina. Cultural control measures that diminished ZYMV spread in pumpkin included manipulation of planting date to avoid exposing young plants to peak aphid vector populations, deploying tall non-host barriers (millet, Pennisetum glaucum) to protect against incoming aphid vectors and planting upwind of infection sources. Clustering of ZYMV-infected pumpkin plants was greater without a 25m wide non-host barrier between the infection source and the pumpkin plants than when one was present, and downwind compared with upwind of an infection source. Host resistance gene zym was effective against ZYMV isolate Knx-1 from Kununurra in five cultivars of cucumber. In zucchini, host resistance gene Zym delayed spread of infection (partial resistance) in 2 of 14 cultivars but otherwise did not diminish final ZYMV incidence. Zucchini cultivars carrying Zym often developed severe fruit symptoms (8/14), and only the two cultivars in which spread was delayed and one that was tolerant produced sufficiently high marketable yields to be recommended when ZYMV epidemics are anticipated. In three pumpkin cultivars with Zym, this gene was effective against isolate Cvn-1 from Carnarvon under low inoculum pressure, but not against isolate Knx-1 under high inoculum pressure, although symptoms were milder and marketable yields greater in them than in cultivars without Zym. These findings allowed additional cultural control recommendations to be added

  18. Improvement of Sulphur Resistance of a Nickel-modified Catalytic Filter for Tar Removal from Biomass Gasification Gas

    SciTech Connect

    Zhang, Y.; Draelants, D.J.; Engelen, K.; Baron, G.V.

    2002-09-19

    This work focuses on the development of catalytic candle filters for the simultaneous removal of tars and particles from the biomass gasification gas at high temperature. An improvement of sulphur resistance of the nickel-activated catalytic filter was developed by the addition of CaO. The influences of preparation procedure of catalytic filter, the ratio of Ni/CaO and the loading of Ni and CaO on the performance of the catalytic filter were investigated.

  19. Carbapenem-Resistant Klebsiella pneumoniae Strains Exhibit Diversity in Aminoglycoside-Modifying Enzymes, Which Exert Differing Effects on Plazomicin and Other Agents

    PubMed Central

    Almaghrabi, Reem; Doi, Yohei; Hao, Binghua; Chen, Liang; Shields, Ryan K.; Press, Ellen G.; Iovine, Nicole M.; Townsend, Bethany M.; Wagener, Marilyn M.; Kreiswirth, Barry; Nguyen, M. Hong

    2014-01-01

    We measured in vitro activity of plazomicin, a next-generation aminoglycoside, and other aminoglycosides against 50 carbapenem-resistant Klebsiella pneumoniae strains from two centers and correlated the results with the presence of various aminoglycoside-modifying enzymes (AMEs). Ninety-four percent of strains were sequence type 258 (ST258) clones, which exhibited 5 ompK36 genotypes; 80% and 10% of strains produced Klebsiella pneumoniae carbapenemase 2 (KPC-2) and KPC-3, respectively. Ninety-eight percent of strains possessed AMEs, including AAC(6′)-Ib (98%), APH(3′)-Ia (56%), AAC(3)-IV (38%), and ANT(2″)-Ia (2%). Gentamicin, tobramycin, and amikacin nonsusceptibility rates were 40, 98, and 16%, respectively. Plazomicin MICs ranged from 0.25 to 1 μg/ml. Tobramycin and plazomicin MICs correlated with gentamicin MICs (r = 0.75 and 0.57, respectively). Plazomicin exerted bactericidal activity against 17% (1× MIC) and 94% (4× MIC) of strains. All strains with AAC(6′)-Ib were tobramycin-resistant; 16% were nonsusceptible to amikacin. AAC(6′)-Ib combined with another AME was associated with higher gentamicin, tobramycin, and plazomicin MICs than AAC(6′)-Ib alone (P = 0.01, 0.0008, and 0.046, respectively). The presence of AAC(3)-IV in a strain was also associated with higher gentamicin, tobramycin, and plazomicin MICs (P = 0.0006, P < 0.0001, and P = 0.01, respectively). The combination of AAC(6′)-Ib and another AME, the presence of AAC(3)-IV, and the presence of APH(3′)-Ia were each associated with gentamicin resistance (P = 0.0002, 0.003, and 0.01, respectively). In conclusion, carbapenem-resistant K. pneumoniae strains (including ST258 clones) exhibit highly diverse antimicrobial resistance genotypes and phenotypes. Plazomicin may offer a treatment option against strains resistant to other aminoglycosides. The development of molecular assays that predict antimicrobial responses among carbapenem-resistant K. pneumoniae strains should be a research

  20. Extreme resistance to potato virus X infection in plants expressing a modified component of the putative viral replicase.

    PubMed Central

    Longstaff, M; Brigneti, G; Boccard, F; Chapman, S; Baulcombe, D

    1993-01-01

    Three types of mutation were introduced into the sequence encoding the GDD motif of the putative replicase component of potato virus X (PVX). All three mutations rendered the viral genome completely noninfectious when inoculated into Nicotiana clevelandii or into protoplasts of Nicotiana tabacum (cv. Samsun NN). In order to test whether these negative mutations could inactivate the viral genome in trans, the mutant genes were expressed in transformed N.tabacum (cv. Samsun NN) under control of the 35S RNA promoter of cauliflower mosaic virus and the transformed lines were inoculated with PVX. In 10 lines tested in which the GDD motif was expressed as GAD or GED there was no effect on susceptibility to PVX. In two of four lines transformed to express the ADD form of the conserved motif, the F1 and F2 progeny plants were highly resistant to infection by PVX, although only to strains closely related to the source of the transgene. The resistance was associated with suppression of PVX accumulation in the inoculated and systemic leaves and in protoplasts of the transformed plants, although some low level viral RNA production was observed in the inoculated but not the systemic leaves when the inoculum was as high as 100 or 250 micrograms/ml PVX RNA. These results suggest for a plant virus, as reported previously for Q beta phage, that virus resistance may be engineered by expression of dominant negative mutant forms of viral genes in transformed cells. Images PMID:8440232

  1. Characterization of the Metabolically Modified Heavy Metal-Resistant Cupriavidus metallidurans Strain MSR33 Generated for Mercury Bioremediation

    PubMed Central

    Rojas, Luis A.; Yáñez, Carolina; González, Myriam; Lobos, Soledad; Smalla, Kornelia; Seeger, Michael

    2011-01-01

    Background Mercury-polluted environments are often contaminated with other heavy metals. Therefore, bacteria with resistance to several heavy metals may be useful for bioremediation. Cupriavidus metallidurans CH34 is a model heavy metal-resistant bacterium, but possesses a low resistance to mercury compounds. Methodology/Principal Findings To improve inorganic and organic mercury resistance of strain CH34, the IncP-1β plasmid pTP6 that provides novel merB, merG genes and additional other mer genes was introduced into the bacterium by biparental mating. The transconjugant Cupriavidus metallidurans strain MSR33 was genetically and biochemically characterized. Strain MSR33 maintained stably the plasmid pTP6 over 70 generations under non-selective conditions. The organomercurial lyase protein MerB and the mercuric reductase MerA of strain MSR33 were synthesized in presence of Hg2+. The minimum inhibitory concentrations (mM) for strain MSR33 were: Hg2+, 0.12 and CH3Hg+, 0.08. The addition of Hg2+ (0.04 mM) at exponential phase had not an effect on the growth rate of strain MSR33. In contrast, after Hg2+ addition at exponential phase the parental strain CH34 showed an immediate cessation of cell growth. During exposure to Hg2+ no effects in the morphology of MSR33 cells were observed, whereas CH34 cells exposed to Hg2+ showed a fuzzy outer membrane. Bioremediation with strain MSR33 of two mercury-contaminated aqueous solutions was evaluated. Hg2+ (0.10 and 0.15 mM) was completely volatilized by strain MSR33 from the polluted waters in presence of thioglycolate (5 mM) after 2 h. Conclusions/Significance A broad-spectrum mercury-resistant strain MSR33 was generated by incorporation of plasmid pTP6 that was directly isolated from the environment into C. metallidurans CH34. Strain MSR33 is capable to remove mercury from polluted waters. This is the first study to use an IncP-1β plasmid directly isolated from the environment, to generate a novel and stable bacterial strain

  2. Genome editing for crop improvement: Challenges and opportunities.

    PubMed

    Abdallah, Naglaa A; Prakash, Channapatna S; McHughen, Alan G

    2015-01-01

    Genome or gene editing includes several new techniques to help scientists precisely modify genome sequences. The techniques also enables us to alter the regulation of gene expression patterns in a pre-determined region and facilitates novel insights into the functional genomics of an organism. Emergence of genome editing has brought considerable excitement especially among agricultural scientists because of its simplicity, precision and power as it offers new opportunities to develop improved crop varieties with clear-cut addition of valuable traits or removal of undesirable traits. Research is underway to improve crop varieties with higher yields, strengthen stress tolerance, disease and pest resistance, decrease input costs, and increase nutritional value. Genome editing encompasses a wide variety of tools using either a site-specific recombinase (SSR) or a site-specific nuclease (SSN) system. Both systems require recognition of a known sequence. The SSN system generates single or double strand DNA breaks and activates endogenous DNA repair pathways. SSR technology, such as Cre/loxP and Flp/FRT mediated systems, are able to knockdown or knock-in genes in the genome of eukaryotes, depending on the orientation of the specific sites (loxP, FLP, etc.) flanking the target site. There are 4 main classes of SSN developed to cleave genomic sequences, mega-nucleases (homing endonuclease), zinc finger nucleases (ZFNs), transcriptional activator-like effector nucleases (TALENs), and the CRISPR/Cas nuclease system (clustered regularly interspaced short palindromic repeat/CRISPR-associated protein). The recombinase mediated genome engineering depends on recombinase (sub-) family and target-site and induces high frequencies of homologous recombination. Improving crops with gene editing provides a range of options: by altering only a few nucleotides from billions found in the genomes of living cells, altering the full allele or by inserting a new gene in a targeted region of

  3. Genome editing for crop improvement: Challenges and opportunities

    PubMed Central

    Abdallah, Naglaa A; Prakash, Channapatna S; McHughen, Alan G

    2015-01-01

    ABSTRACT Genome or gene editing includes several new techniques to help scientists precisely modify genome sequences. The techniques also enables us to alter the regulation of gene expression patterns in a pre-determined region and facilitates novel insights into the functional genomics of an organism. Emergence of genome editing has brought considerable excitement especially among agricultural scientists because of its simplicity, precision and power as it offers new opportunities to develop improved crop varieties with clear-cut addition of valuable traits or removal of undesirable traits. Research is underway to improve crop varieties with higher yields, strengthen stress tolerance, disease and pest resistance, decrease input costs, and increase nutritional value. Genome editing encompasses a wide variety of tools using either a site-specific recombinase (SSR) or a site-specific nuclease (SSN) system. Both systems require recognition of a known sequence. The SSN system generates single or double strand DNA breaks and activates endogenous DNA repair pathways. SSR technology, such as Cre/loxP and Flp/FRT mediated systems, are able to knockdown or knock-in genes in the genome of eukaryotes, depending on the orientation of the specific sites (loxP, FLP, etc.) flanking the target site. There are 4 main classes of SSN developed to cleave genomic sequences, mega-nucleases (homing endonuclease), zinc finger nucleases (ZFNs), transcriptional activator-like effector nucleases (TALENs), and the CRISPR/Cas nuclease system (clustered regularly interspaced short palindromic repeat/CRISPR-associated protein). The recombinase mediated genome engineering depends on recombinase (sub-) family and target-site and induces high frequencies of homologous recombination. Improving crops with gene editing provides a range of options: by altering only a few nucleotides from billions found in the genomes of living cells, altering the full allele or by inserting a new gene in a targeted

  4. Silver-nanoparticles-modified biomaterial surface resistant to staphylococcus: new insight into the antimicrobial action of silver

    PubMed Central

    Wang, Jiaxing; Li, Jinhua; Guo, Geyong; Wang, Qiaojie; Tang, Jin; Zhao, Yaochao; Qin, Hui; Wahafu, Tuerhongjiang; Shen, Hao; Liu, Xuanyong; Zhang, Xianlong

    2016-01-01

    Titanium implants are widely used clinically, but postoperative implant infection remains a potential severe complication. The purpose of this study was to investigate the antibacterial activity of nano-silver(Ag)-functionalized Ti surfaces against epidemic Staphylococcus from the perspective of the regulation of biofilm-related genes and based on a bacteria-cell co-culture study. To achieve this goal, two representative epidemic Staphylococcus strains, Staphylococcus epidermidis (S. epidermidis, RP62A) and Staphylococcus aureus (S. aureus, USA 300), were used, and it was found that an Ag-nanoparticle-modified Ti surface could regulate the expression levels of biofilm-related genes (icaA and icaR for S. epidermidis; fnbA and fnbB for S. aureus) to inhibit bacterial adhesion and biofilm formation. Moreover, a novel bacteria-fibroblast co-culture study revealed that the incorporation of Ag nanoparticles on such a surface can help mammalian cells to survive, adhere and spread more successfully than Staphylococcus. Therefore, the modified surface was demonstrated to possess a good anti-infective capability against both sessile bacteria and planktonic bacteria through synergy between the effects of Ag nanoparticles and ion release. This work provides new insight into the antimicrobial action and mechanism of Ag-nanoparticle-functionalized Ti surfaces with bacteria-killing and cell-assisting capabilities and paves the way towards better satisfying the clinical needs. PMID:27599568

  5. Glyphosate sustainability in South American cropping systems.

    PubMed

    Christoffoleti, Pedro J; Galli, Antonio J B; Carvalho, Saul J P; Moreira, Murilo S; Nicolai, Marcelo; Foloni, Luiz L; Martins, Bianca A B; Ribeiro, Daniela N

    2008-04-01

    South America represents about 12% of the global land area, and Brazil roughly corresponds to 47% of that. The major sustainable agricultural system in South America is based on a no-tillage cropping system, which is a worldwide adopted agricultural conservation system. Societal benefits of conservation systems in agriculture include greater use of conservation tillage, which reduces soil erosion and associated loading of pesticides, nutrients and sediments into the environment. However, overreliance on glyphosate and simpler cropping systems has resulted in the selection of tolerant weed species through weed shifts (WSs) and evolution of herbicide-resistant weed (HRW) biotypes to glyphosate. It is a challenge in South America to design herbicide- and non-herbicide-based strategies that effectively delay and/or manage evolution of HRWs and WSs to weeds tolerant to glyphosate in cropping systems based on recurrent glyphosate application, such as those used with glyphosate-resistant soybeans. The objectives of this paper are (i) to provide an overview of some factors that influence WSs and HRWs to glyphosate in South America, especially in Brazil, Argentina and Paraguay soybean cropped areas; (ii) to discuss the viability of using crop rotation and/or cover crops that might be integrated with forage crops in an economically and environmentally sustainable system; and (iii) to summarize the results of a survey of the perceptions of Brazilian farmers to problems with WSs and HRWs to glyphosate, and the level of adoption of good agricultural practices in order to prevent or manage it.

  6. Technical Note: On the Matt-Shuttleworth approach to estimate crop water requirements

    NASA Astrophysics Data System (ADS)

    Lhomme, J. P.; Boudhina, N.; Masmoudi, M. M.

    2014-11-01

    The Matt-Shuttleworth method provides a way to make a one-step estimate of crop water requirements with the Penman-Monteith equation by translating the crop coefficients, commonly available in United Nations Food and Agriculture Organization (FAO) publications, into equivalent surface resistances. The methodology is based upon the theoretical relationship linking crop surface resistance to a crop coefficient and involves the simplifying assumption that the reference crop evapotranspiration (ET0) is equal to the Priestley-Taylor estimate with a fixed coefficient of 1.26. This assumption, used to eliminate the dependence of surface resistance on certain weather variables, is questionable; numerical simulations show that it can lead to substantial differences between the true value of surface resistance and its estimate. Consequently, the basic relationship between surface resistance and crop coefficient, without any assumption, appears to be more appropriate for inferring crop surface resistance, despite the interference of weather variables.

  7. Decay resistance of thermally-modified Eucalyptus grandis wood at 140 degrees C, 160 degrees C, 180 degrees C, 200 degrees C and 220 degrees C.

    PubMed

    Calonego, Fred Willians; Severo, Elias Taylor Durgante; Furtado, Edson Luiz

    2010-12-01

    The objective of this study was to evaluate the effect of thermal treatment on the biological resistance of Eucalyptus grandis wood to the decay fungus Picnoporus sanguineus. Boards from 5 years and 11 months old E. grandis trees, taken from the stock possessed by the Duratex-SA company, were thermally-modified at 140 degrees C, 160 degrees C, 180 degrees C, 200 degrees C and 220 degrees C in the Laboratory of Wood Drying and Preservation from UNESP, Botucatu, SP, Brazil. Samples of each treatment were treated according to ASTM D-2017 (1994). The experiment tested the accelerated decay caused by the decay fungus P. sanguineus on a system of soil-block wood. The results of thermal treatment showed that an increase of temperature of 180-220 degrees C caused reductions of between 15.7% and 82.4% in the weight loss in the samples from E. grandis incubated with P. sanguineus.

  8. Adsorption of mercury from water by modified multi-walled carbon nanotubes: adsorption behaviour and interference resistance by coexisting anions.

    PubMed

    Chen, Paris Honglay; Hsu, Cheng-Feng; Tsai, David Dah-wei; Lu, Yen-Ming; Huang, Winn-Jung

    2014-08-01

    This investigation reports the use of modified multi-walled carbon nanotubes (MWCNTs) with various functional groups for adsorbing inorganic divalent mercury (Hg(II)) from water samples. To elucidate the behaviours and mechanisms of Hg(II) adsorption by modified MWCNTs, their adsorption capacity was studied by considering adsorption isotherms and kinetics. Particular attention was paid to interference of coexisting inorganic ions with Hg(II) adsorption. The results reveal that functionalization with oxygen-containing groups improved the Hg(II) adsorption capacity of the MWCNTs. Kinetic analysis demonstrated that the adsorption of Hg(II) by MWCNTs was closely described by the pseudo-second-order and Elovich models, suggesting that the adsorption of Hg(II) by MWCNTs was significantly affected by chemical adsorption. The kinetic results were also analysed using the intraparticle diffusion model, which revealed that intraparticle diffusion was not the only rate-controlling mechanism. The adsorption of Hg(II) on MWCNTs fell drastically as the ionic strength increased from 0 to 1.0mol/L chloride ions, and declined significantly as the pH increased from 2.2 to 10.5. The elemental maps obtained by energy-dispersive spectrometer (EDS) revealed the formation of surface complexes of chloride ions with functional groups on MWCNTs, which reduced the number of available sites for the adsorption of Hg(II) and strengthened the repulsive forces between Hg(II) and MWCNTs. The EDS results suggest that chloride ions are important in controlling Hg(II) speciation and adsorption on the surfaces of MWCNTs.

  9. Genetically Modified Foods and Social Concerns

    PubMed Central

    Maghari, Behrokh Mohajer; Ardekani, Ali M.

    2011-01-01

    Biotechnology is providing us with a wide range of options for how we can use agricultural and commercial forestry lands. The cultivation of genetically modified (GM) crops on millions of hectares of lands and their injection into our food chain is a huge global genetic experiment involving all living beings. Considering the fast pace of new advances in production of genetically modified crops, consumers, farmers and policymakers worldwide are challenged to reach a consensus on a clear vision for the future of world food supply. The current food biotechnology debate illustrates the serious conflict between two groups: 1) Agri-biotech investors and their affiliated scientists who consider agricultural biotechnology as a solution to food shortage, the scarcity of environmental resources and weeds and pests infestations; and 2) independent scientists, environmentalists, farmers and consumers who warn that genetically modified food introduces new risks to food security, the environment and human health such as loss of biodiversity; the emergence of superweeds and superpests; the increase of antibiotic resistance, food allergies and other unintended effects. This article reviews major viewpoints which are currently debated in the food biotechnology sector in the world. It also lays the ground-work for deep debate on benefits and risks of Biotech-crops for human health, ecosystems and biodiversity. In this context, although some regulations exist, there is a need for continuous vigilance for all countries involved in producing genetically engineered food to follow the international scientific bio-safety testing guidelines containing reliable pre-release experiments and post-release track of transgenic plants to protect public health and avoid future environmental harm. PMID:23408723

  10. Genetically modified foods and social concerns.

    PubMed

    Maghari, Behrokh Mohajer; Ardekani, Ali M

    2011-07-01

    Biotechnology is providing us with a wide range of options for how we can use agricultural and commercial forestry lands. The cultivation of genetically modified (GM) crops on millions of hectares of lands and their injection into our food chain is a huge global genetic experiment involving all living beings. Considering the fast pace of new advances in production of genetically modified crops, consumers, farmers and policymakers worldwide are challenged to reach a consensus on a clear vision for the future of world food supply. The current food biotechnology debate illustrates the serious conflict between two groups: 1) Agri-biotech investors and their affiliated scientists who consider agricultural biotechnology as a solution to food shortage, the scarcity of environmental resources and weeds and pests infestations; and 2) independent scientists, environmentalists, farmers and consumers who warn that genetically modified food introduces new risks to food security, the environment and human health such as loss of biodiversity; the emergence of superweeds and superpests; the increase of antibiotic resistance, food allergies and other unintended effects. This article reviews major viewpoints which are currently debated in the food biotechnology sector in the world. It also lays the ground-work for deep debate on benefits and risks of Biotech-crops for human health, ecosystems and biodiversity. In this context, although some regulations exist, there is a need for continuous vigilance for all countries involved in producing genetically engineered food to follow the international scientific bio-safety testing guidelines containing reliable pre-release experiments and post-release track of transgenic plants to protect public health and avoid future environmental harm.

  11. Locus-dependent selection in crop-wild hybrids of lettuce under field conditions and its implication for GM crop development.

    PubMed

    Hooftman, Danny A P; Flavell, Andrew J; Jansen, Hans; den Nijs, Hans C M; Syed, Naeem H; Sørensen, Anker P; Orozco-Ter Wengel, Pablo; van de Wiel, Clemens C M

    2011-09-01

    Gene escape from crops has gained much attention in the last two decades, as transgenes introgressing into wild populations could affect the latter's ecological characteristics. However, different genes have different likelihoods of introgression. The mixture of selective forces provided by natural conditions creates an adaptive mosaic of alleles from both parental species. We investigated segregation patterns after hybridization between lettuce (Lactuca sativa) and its wild relative, L. serriola. Three generations of hybrids (S1, BC1, and BC1S1) were grown in habitats mimicking the wild parent's habitat. As control, we harvested S1 seedlings grown under controlled conditions, providing very limited possibility for selection. We used 89 AFLP loci, as well as more recently developed dominant markers, 115 retrotransposon markers (SSAP), and 28 NBS loci linked to resistance genes. For many loci, allele frequencies were biased in plants exposed to natural field conditions, including over-representation of crop alleles for various loci. Furthermore, Linkage disequilibrium was locally changed, allegedly by selection caused by the natural field conditions, providing ample opportunity for genetic hitchhiking. Our study indicates that when developing genetically modified crops, a judicious selection of insertion sites, based on knowledge of selective (dis)advantages of the surrounding crop genome under field conditions, could diminish transgene persistence.

  12. Yield of glyphosate-resistant sugar beets and efficiency of weed management systems with glyphosate and conventional herbicides under German and Polish crop production.

    PubMed

    Nichterlein, Henrike; Matzk, Anja; Kordas, Leszek; Kraus, Josef; Stibbe, Carsten

    2013-08-01

    In sugar beet production, weed control is one of the most important and most expensive practices to ensure yield. Since glyphosate-resistant sugar beets are not yet approved for cultivation in the EU, little commercial experience exists with these sugar beets in Europe. Experimental field trials were conducted at five environments (Germany, Poland, 2010, 2011) to compare the effects of glyphosate with the effects of conventional weed control programs on the development of weeds, weed control efficiency and yield. The results show that the glyphosate weed control programs compared to the conventional methods decreased not only the number of herbicide applications but equally in magnitude decreased the dosage of active ingredients. The results also showed effective weed control with glyphosate when the weed covering was greater and sugar beets had a later growth stage of four true leaves. Glyphosate-resistant sugar beets applied with the glyphosate herbicide two or three times had an increase in white sugar yield from 4 to 18 % in comparison to the high dosage conventional herbicide systems. In summary, under glyphosate management sugar beets can positively contribute to the increasingly demanding requirements regarding efficient sugar beet cultivation and to the demands by society and politics to reduce the use of chemical plant protection products in the environment.

  13. Wind Turbines Benefit Crops

    SciTech Connect

    Takle, Gene

    2010-01-01

    Ames Laboratory associate scientist Gene Takle talks about research into the effect of wind turbines on nearby crops. Preliminary results show the turbines may have a positive effect by cooling and drying the crops and assisting with carbon dioxide uptake.

  14. Wind Turbines Benefit Crops

    ScienceCinema

    Takle, Gene

    2016-07-12

    Ames Laboratory associate scientist Gene Takle talks about research into the effect of wind turbines on nearby crops. Preliminary results show the turbines may have a positive effect by cooling and drying the crops and assisting with carbon dioxide uptake.

  15. Rapeseed species and environmental concerns related to loss of seeds of genetically modified oilseed rape in Japan.

    PubMed

    Nishizawa, Toru; Tamaoki, Masanori; Aono, Mitsuko; Kubo, Akihiro; Saji, Hikaru; Nakajima, Nobuyoshi

    2010-01-01

    Feral rapeseed in Japan consists of Brassica rapa, B. juncea and B. napus, mostly produced by escape from crops. Brassica rapa and B. juncea were introduced from abroad long ago as leaf and root vegetables and as an oil crop and breeders have developed various cultivars. Brassica napus was introduced in the late 1800s, mainly as an oil crop. Rapeseed production in Japan is low, and most demand is met by imports from Canada (94.4% of the 2009 trade volume). Recently, spontaneous B. napus, including genetically modified (GM) herbicide-resistant individuals, has been detected along Japanese roads, probably originating from seeds lost during transportation of imports. As GM oilseed production increases abroad, the probability of escape of GM oilseed rape in Japan will increase, raising environmental biosafety concerns related to the impact of feral rapeseed on heirloom brassicaceous crops. In this paper, we review the history of rapeseed introduction in Japan and future concerns.

  16. Dealing with transgene flow of crop protection traits from crops to their relatives.

    PubMed

    Gressel, Jonathan

    2015-05-01

    Genes regularly move within species, to/from crops, as well as to their con- specific progenitors, feral and weedy forms ('vertical' gene flow). Genes occasionally move to/from crops and their distantly related, hardly sexually interbreeding relatives, within a genus or among closely related genera (diagonal gene flow). Regulators have singled out transgene flow as an issue, yet non-transgenic herbicide resistance traits pose equal problems, which cannot be mitigated. The risks are quite different from genes flowing to natural (wild) ecosystems versus ruderal and agroecosystems. Transgenic herbicide resistance poses a major risk if introgressed into weedy relatives; disease and insect resistance less so. Technologies have been proposed to contain genes within crops (chloroplast transformation, male sterility) that imperfectly prevent gene flow by pollen to the wild. Containment does not prevent related weeds from pollinating crops. Repeated backcrossing with weeds as pollen parents results in gene establishment in the weeds. Transgenic mitigation relies on coupling crop protection traits in a tandem construct with traits that lower the fitness of the related weeds. Mitigation traits can be morphological (dwarfing, no seed shatter) or chemical (sensitivity to a chemical used later in a rotation). Tandem mitigation traits are genetically linked and will move together. Mitigation traits can also be spread by inserting them in multicopy transposons which disperse faster than the crop protection genes in related weeds. Thus, there are gene flow risks mainly to weeds from some crop protection traits; risks that can and should be dealt with.

  17. The Gene Controlling the Quantitative Trait Locus EPITHIOSPECIFIER MODIFIER1 Alters Glucosinolate Hydrolysis and Insect Resistance in Arabidopsis[W

    PubMed Central

    Zhang, Zhiyong; Ober, James A.; Kliebenstein, Daniel J.

    2006-01-01

    Glucosinolates are sulfur-rich plant secondary metabolites whose breakdown products have a wide range of biological activities in plant–herbivore and plant–pathogen interactions and anticarcinogenic properties. In Arabidopsis thaliana, hydrolysis by the enzyme, myrosinase, produces bioactive nitriles, epithionitriles, or isothiocyanates depending upon the plant's genotype and the glucosinolate's structure. A major determinant of this structural specificity is the epithiospecifier locus (ESP), whose protein causes the formation of epithionitriles and nitriles. A quantitative trait locus (QTL) on chromosome 3 epistatically affects nitrile formation in combination with ESP; this QTL has been termed EPITHIOSPECIFIER MODIFIER1 (ESM1). We identified a myrosinase-associated protein as the ESM1 QTL in Arabidopsis using map-based cloning with recombinant inbred lines, natural variation transcriptomic analysis, and metabolic profiling. In planta and in vitro analyses with natural ESM1 alleles, ESM1 knockouts, and overexpression lines show that ESM1 represses nitrile formation and favors isothiocyanate production. The glucosinolate hydrolysis profile change influenced by ESM1 is associated with the ability to deter herbivory by Trichoplusia ni. This gene could provide unique approaches toward improving human nutrition. PMID:16679459

  18. Combined effects of gamma irradiation and modified atmosphere packaging on bacterial resistance in grated carrots ( Daucus carota)

    NASA Astrophysics Data System (ADS)

    Lacroix, M.; Lafortune, R.

    2004-09-01

    The present study was conducted to evaluate the efficiency of gamma irradiation combined with modified atmosphere packaging as an alternative treatment to ensure the innocuity and the shelf life extension of pre-cured vegetables. Grated carrots were inoculated with Escherichia coli (10 6 CFU/g) and packed under air or under MAP condition (60% O 2, 30% CO 2 and 10% N 2). The packages were then, gamma irradiated at doses from 0.15 to 0.9 kGy and stored at 4±1°C. E. coli counts were periodically evaluated during 50 days of storage. Results showed that at day 1, an irradiation treatment at a dose of 0.15 kGy reduced by 3 and 4 log the microbial level representing a level of 3 and 2 log CFU/g when samples were irradiated under air and under MAP respectively. However, a level of 3 log CFU/g was detected in both treated samples after 7 days of storage. When samples were irradiated at doses ⩾0.3 kGy no E.coli were detected during the whole storage in samples treated under MAP. However, when samples were treated under air, a level of 1-2 log CFU/g of E.coli was detected after 5 days of storage.

  19. New indicators for global crop monitoring in CropWatch -case study in North China Plain

    NASA Astrophysics Data System (ADS)

    Bingfang, Wu; Miao, Zhang; Hongwei, Zeng; Guoshui, Liu; Sheng, Chang; Gommes, René