977 resultados para Genetically modified seeds
Resumo:
A rider to a US law, the Consolidated and Continuing Appropriations Act, 2013, known as the Farmer Assurance Provision, encourages the large-scale genetic modification and global distribution of agricultural crops, thereby undermining the Food and Agriculture Organization of the United Nations' determination that food security rests on biodiversity. The rider blocks the US Department of Agriculture's mandate to prohibit farmers from growing crops from biotechnological seeds where the courts have found that this farm practice may cause damage to human health and/or degrade the environment. Despite genetically modified organisms (GMOs) reducing unwanted traits in plants, the paper supports the UN's mission for biodiversity and that more long-term testing was (and is) needed for GMO products, developed from 1994 on, before a hasty piece of Congressional legislation as was made in this case.
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Uncoupling protein one (UCP1) is a mitochondrial inner membrane protein capable of uncoupling the electrochemical gradient from adenosine-5'-triphosphate (ATP) synthesis, dissipating energy as heat. UCP1 plays a central role in nonshivering thermogenesis in the brown adipose tissue (BAT) of hibernating animals and small rodents. A UCP1 ortholog also occurs in plants, and aside from its role in uncoupling respiration from ATP synthesis, thereby wasting energy, it plays a beneficial role in the plant response to several abiotic stresses, possibly by decreasing the production of reactive oxygen species (ROS) and regulating cellular redox homeostasis. However, the molecular mechanisms by which UCP1 is associated with stress tolerance remain unknown. Here, we report that the overexpression of UCP1 increases mitochondrial biogenesis, increases the uncoupled respiration of isolated mitochondria, and decreases cellular ATP concentration. We observed that the overexpression of UCP1 alters mitochondrial bioenergetics and modulates mitochondrial-nuclear communication, inducing the upregulation of hundreds of nuclear- and mitochondrial-encoded mitochondrial proteins. Electron microscopy analysis showed that these metabolic changes were associated with alterations in mitochondrial number, area and morphology. Surprisingly, UCP1 overexpression also induces the upregulation of hundreds of stress-responsive genes, including some involved in the antioxidant defense system, such as superoxide dismutase (SOD), glutathione peroxidase (GPX) and glutathione-S-transferase (GST). As a consequence of the increased UCP1 activity and increased expression of oxidative stress-responsive genes, the UCP1-overexpressing plants showed reduced ROS accumulation. These beneficial metabolic effects may be responsible for the better performance of UCP1-overexpressing lines in low pH, high salt, high osmolarity, low temperature, and oxidative stress conditions. Overexpression of UCP1 in the mitochondrial inner membrane induced increased uncoupling respiration, decreased ROS accumulation under abiotic stresses, and diminished cellular ATP content. These events may have triggered the expression of mitochondrial and stress-responsive genes in a coordinated manner. Because these metabolic alterations did not impair plant growth and development, UCP1 overexpression can potentially be used to create crops better adapted to abiotic stress conditions.
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Genetically modified foods are a major concern around the world due to the lack of information concerning their safety and health effects. This work evaluates differences, at the proteomic level, between two types of crop samples: transgenic (MON810 event with the Cry1Ab gene, which confers resistance to insects) and non-transgenic maize flour commercialized in Brazil. The 2-D DIGE technique revealed 99 differentially expressed spots, which were collected in 2-D PAGE gels and identified via mass spectrometry (nESI-QTOF MS/MS). The abundance of protein differences between the transgenic and non-transgenic samples could arise from genetic modification or as a result of an environmental influence pertaining to the commercial sample. The major functional category of proteins identified was related to disease/defense and, although differences were observed between samples, no toxins or allergenic proteins were found.
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Formas químicas de controle de mosquitos vetores são ineficazes, levando ao desenvolvimento de novas estratégias. Assim, foi realizada revisão das estratégias de controle genético de populações de mosquitos vetores baseada na técnica do inseto estéril. Uma delas consiste na liberação de machos esterilizados por radiação, a outra, na integração de um gene letal dominante associado a um promotor específico de fêmeas imaturas. Entre as vantagens sobre outras técnicas biológicas e químicas de controle de vetores estão: alta especificidade, não prejudicial ao meio ambiente, baixo custo de produção e alta eficácia. O uso desta técnica de modificação genética pode vir a ser uma importante ferramenta do manejo integrado de vetores
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Overwhelming evidence supports the importance of the sympathetic nervous system in heart failure. In contrast, much less is known about the role of failing cholinergic neurotransmission in cardiac disease. By using a unique genetically modified mouse line with reduced expression of the vesicular acetylcholine transporter (VAChT) and consequently decreased release of acetylcholine, we investigated the consequences of altered cholinergic tone for cardiac function. M-mode echocardiography, hemodynamic experiments, analysis of isolated perfused hearts, and measurements of cardiomyocyte contraction indicated that VAChT mutant mice have decreased left ventricle function associated with altered calcium handling. Gene expression was analyzed by quantitative reverse transcriptase PCR and Western blotting, and the results indicated that VAChT mutant mice have profound cardiac remodeling and reactivation of the fetal gene program. This phenotype was attributable to reduced cholinergic tone, since administration of the cholinesterase inhibitor pyridostigmine for 2 weeks reversed the cardiac phenotype in mutant mice. Our findings provide direct evidence that decreased cholinergic neurotransmission and underlying autonomic imbalance cause plastic alterations that contribute to heart dysfunction.
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The diversity of endophytic filamentous fungi from leaves of transgenic imidazolinone-tolerant sugarcane plants and its isoline was evaluated by cultivation followed by amplified rDNA restriction analysis (ARDRA) of randomly selected strains. Transgenic and non-transgenic cultivars and their crop management (herbicide application or manual weed control) were used to assess the possible non-target effects of genetically modified sugarcane on the fungal endophytic community. A total of 14 ARDRA haplotypes were identified in the endophytic community of sugarcane. Internal transcribed spacer (ITS) sequencing revealed a rich community represented by 12 different families from the Ascomycota phylum. Some isolates had a high sequence similarity with genera that are common endophytes in tropical climates, such as Cladosporium, Epicoccum, Fusarium, Guignardia, Pestalotiopsis and Xylaria. Analysis of molecular variance indicated that fluctuations in fungal population were related to both transgenic plants and herbicide application. While herbicide applications quickly induced transient changes in the fungal community, transgenic plants induced slower changes that were maintained over time. These results represent the first draft on composition of endophytic filamentous fungi associated with sugarcane plants. They are an important step in understanding the possible effects of transgenic plants and their crop management on the fungal endophytic community.
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The rhizosphere is a niche exploited by a wide variety of bacteria. The expression of heterologous genes by plants might become a factor affecting the structure of bacterial communities in the rhizosphere. In a greenhouse experiment, the bacterial community associated to transgenic eucalyptus, carrying the Lhcb1-2 genes from pea (responsible for a higher photosynthetic capacity), was evaluated. The culturable bacterial community associated to transgenic and wild type plants were not different in density, and the Amplified Ribosomal DNA Restriction Analysis (ARDRA) typing of 124 strains revealed dominant ribotypes representing the bacterial orders Burkholderiales, Rhizobiales, and Actinomycetales, the families Xanthomonadaceae, and Bacillaceae, and the genus Mycobacterium. Principal Component Analysis based on the fingerprints obtained by culture-independent Denaturing Gradient Gel Electrophoresis analysis revealed that Alphaproteobacteria, Betaproteobacteria and Actinobacteria communities responded differently to plant genotypes. Similar effects for the cultivation of transgenic eucalyptus to those observed when two genotype-distinct wild type plants are compared.
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BACKGROUND: Biosurfactant production was investigated using two strains of Bacillus subtilis, one being a reference strain (B. subtilis 1012) and the other a recombinant of this (B. subtilis W1012) made able to produce the green fluorescent protein (GFP). RESULTS: Batch cultivations carried out at different initial levels of glucose (GO) in the presence of 10 g L(-1) casein demonstrated that the reference strain was able to release higher levels of biosurfactants in the medium at 5.0 <= G(0) <= 10 g L(-1) (B(max) = 104-110 mg L(-1)). The recombinant strain exhibited slightly lower levels of biosurfactants(B(max) = 90-104 mg L(-1))but only at higher glucose concentrations (G(0) >= 20 g L(-1)). Under these nutritional conditions, the fluorescence intensity linked to the production of GFP was shown to be associated with the cell concentration even after achievement of the stationary phase. CONCLUSION: The ability of the genetically-modified strain to simultaneously overproduce biosurfactant and GFP even at low biomass concentration makes it an interesting candidate for use as a biological indicator to monitor indirectly the biosurfactant production in bioremediation treatments. (C) 2008 Society of Chemical Industry
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Allergy is a major cause of morbidity worldwide. The number of characterized allergens and related information is increasing rapidly creating demands for advanced information storage, retrieval and analysis. Bioinformatics provides useful tools for analysing allergens and these are complementary to traditional laboratory techniques for the study of allergens. Specific applications include structural analysis of allergens, identification of B- and T-cell epitopes, assessment of allergenicity and cross-reactivity, and genome analysis. In this paper, the most important bioinformatic tools and methods with relevance to the study of allergy have been reviewed.
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An efficient system is now in place for improving diverse sugarcane cultivars by genetic transformation, that is, the insertion of useful new genes into single cells followed by the regeneration of genetically modified (transgenic) plants. The method has already been used to introduce genes for resistance to several major diseases, insect pests and a herbicide, Field testing has begun, and research is underway to identify other genes for increased environmental stress resistance, agronomic efficiency and yield of sucrose or other valuable products. Experience in other crops has shown that genetically improved varieties which provide genuine environmental and consumer benefits are welcomed by producers and consumers. Substantial research is still needed, but these new gene technologies will reshape the sugar industry and determine the international competitive efficiency of producers.
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The cellular prion protein (PrPC) is a neuronal anchored glycoprotein that has been associated with distinct functions in the CNS, such as cellular adhesion and differentiation, synaptic plasticity and cognition. Here we investigated the putative involvement of the PrPC in the innate fear-induced behavioural reactions in wild-type (WT), PrPC knockout (Prnp(0/0)) and the PrPC overexpressing Tg-20 mice evoked in a prey versus predator paradigm. The behavioural performance of these mouse strains in olfactory discrimination tasks was also investigated. When confronted with coral snakes, mice from both Prnp(0/0) and Tg-20 strains presented a significant decrease in frequency and duration of defensive attention and risk assessment, compared to WT mice. Tg-20 mice presented decreased frequency of escape responses, increased exploratory behaviour, and enhancement of interaction with the snake, suggesting a robust fearlessness caused by PrPC overexpression. Interestingly, there was also a discrete decrease in the attentional defensive response (decreased frequency of defensive alertness) in Prnp(0/0) mice in the presence of coral snakes. Moreover, Tg-20 mice presented an increased exploration of novel environment and odors. The present findings indicate that the PrPC overexpression causes hyperactivity, fearlessness, and increased preference for visual, tactile and olfactory stimuli-associated novelty, and that the PrPC deficiency might lead to attention deficits. These results suggest that PrPC exerts an important role in the modulation of innate fear and novelty-induced exploration. (C) 2008 Published by Elsevier B.V.
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Treatment of human cancers with an inherent antigen-processing defect due to a loss of peptide transporters (TAP-1 and TAP-2) and/or MHC class I antigen expression remains a considerable challenge. There is now an increasing realization that tumor cells with down-regulated expression of TAP and/or MHC class I antigens display strong resistance to cytotoxic T lymphocyte (CTL)mediated immune control, and often fail to respond to the conventional immunotherapeutic protocols based on active immunization with tumor-associated epitopes (TAE) or adoptive transfer of tumor-specific T cells, In the present study, we describe a novel approach based on immunization with either genetically modified tumor cells or naked DNA vectors encoding TAE fused to an endoplasmic reticulum (ER) signal sequence (ER-TAE) which affords protection against challenge by melanoma cells with down-regulated expression of TAP-1/2 and MHC class I antigens. In contrast, animals immunized with a vaccine based on TAE alone showed no protection against tumor challenge. Although MHC-peptide tetramer analysis showed a similar frequency of antigen-specific CTL in both ER-TAE- and TAE-immunized mice, functional analysis revealed that CTL activated following immunization with ER-TAE displayed significantly higher avidity for TAE when compared to animals immunized with the TAE alone, These observations provide a new strategy in anti-cancer vaccine design that allows activation of a highly effective and well-defined CTL response against tumors with down-regulated expression of TAP and MHC class I antigens.
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The green macroalgal species Caulerpa taxifolia is indigenous to tropical/subtropical Australia, ranging as far south as 28degrees and 29degrees 15' S on the Australian mainland east and west coasts, respectively. The origin of disjunct populations of the species, discovered in 2000 on the Australian mainland east coast at localities to 35degrees S remains unknown, variously attributed to introduced exotic strains or range extensions from other eastern Australian populations. Some naturally occurring Australian populations of C. taxifolia are similar to Mediterranean C. taxifolia. In Australia, large broad forms of the species, which have been known in the region since 1860, grow luxuriantly in sheltered seagrass meadows, with some of these populations tolerating minimum surface seawater temperatures in winter of 12.5 to 14.5degreesC. Accordingly, the contention that the Mediterranean has been invaded by a genetically-modified, large, cold-adapted strain of C. taxifolia may be incorrect. It is crucial that genetic markers (DNA fingerprinting, microsatellites) sensitive at the population level are used to accurately determine the genetic relatedness of C. taxifolia populations.
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Because of subtle differences between mouse and human skin, mice have traditionally not been an ideal model to study melanoma development. Understanding of the molecular mechanisms of melanoma predisposition, however, has been greatly improved by modeling various pathway defects in the mouse. This review analyzes the latest developments in mouse models of melanoma, and summarizes what these may indicate about the development of this neoplasm in humans. Mutations of genes involved in human melanoma have been recapitulated with some unexpected results, particularly with respect to the role of the two transcripts (Ink4a and Arf) encoded by the Cdkn2a locus. Both the Ink4a/pRb and Arf/p53 pathways are involved in melanoma development in mice, and possible mechanisms of cross-talk between the two pathways are discussed. We also know from mouse models that Ras/mitogen-activated protein kinase pathway activation is very important in melanoma development, either through direct activation of Ras (e.g., Hras G12V), or via activation of Ras-effector pathways by other oncogenes (e.g., Ret, Hgf/Sf). Ras can cooperate with the Arf/p53 pathway, and probably the Ink4a/Rb pathway, to induce melanoma. These three growth regulation pathways (Ink4a/pRb, Arf/p53, and Ras/mitogen-activated protein kinase) seem to represent three major axes of melanoma development in mice. Finally, we summarize experiments using genetically modified mice that have given indications of the intensity and timing of ultraviolet radiation exposure that may be most responsible for melanoma development.
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Central to the development of green lifestyles is the consumption of foods that by dint of their status as chemical-free, locally produced and/or free of genetically modified ingredients, reduce the environmental impact of food provision. Yet there are many other factors, such as health concerns, that may also encourage the consumption of 'green' foods. This paper explores the ways in which Australian consumers construct organic food-a sector of the food industry that is currently growing at between 20 and 50 percent per annum but is struggling to keep up with rising consumer demand. In order to examine the significance of 'green' signifiers in the consumption practices of Australian consumers a series of focus group interviews and a national consumer survey were conducted. These examined both those characteristics of food that were valued in general, and those meanings that were associated with organic food in particular. In very general terms, analysis reveals that while consumers believed organic foods to be healthy and environmentally sound-both of which were considered desirable-these characteristics were subsumed by an overarching concern with convenience. This does not mean that consumers did not hold genuinely positive environmental attitudes. Rather, it reflects a range of contradictory beliefs and practices that appeared to derive from the discursive conflict between conventional and organic food industries over environmental, health and safety claims. The paper concludes by identifying the barriers and opportunities for expanding the organic industry in Australia in the context of the ways organics is constructed by consumers.