RESUMEN
Genetically modified (GM) crops that have been engineered to express transgenes have been in commercial use since 1995 and are annually grown on 200 million hectares globally. These crops have provided documented benefits to food security, rural economies, and the environment, with no substantiated case of food, feed, or environmental harm attributable to cultivation or consumption. Despite this extensive history of advantages and safety, the level of regulatory scrutiny has continually increased, placing undue burdens on regulators, developers, and society, while reinforcing consumer distrust of the technology. CropLife International held a workshop at the 16th International Society of Biosafety Research (ISBR) Symposium to examine the scientific basis for modernizing global regulatory frameworks for GM crops. Participants represented a spectrum of global stakeholders, including academic researchers, GM crop developers, regulatory consultants, and regulators. Concurrently examining the considerations of food and feed safety, along with environmental safety, for GM crops, the workshop presented recommendations for a core set of data that should always be considered, and supplementary (i.e., conditional) data that would be warranted only on a case-by-case basis to address specific plausible hypotheses of harm. Then, using a case-study involving a hypothetical GM maize event expressing two familiar traits (insect protection and herbicide tolerance), participants were asked to consider these recommendations and discuss if any additional data might be warranted to support a science-based risk assessment or for regulatory decision-making. The discussions during the workshop highlighted that the set of data to address the food, feed, and environmental safety of the hypothetical GM maize, in relation to a conventional comparator, could be modernized compared to current global regulatory requirements. If these scientific approaches to modernize data packages for GM crop regulation were adopted globally, GM crops could be commercialized in a more timely manner, thereby enabling development of more diverse GM traits to benefit growers, consumers, and the environment.
RESUMEN
DP915635 maize was genetically modified (GM) to express the IPD079Ea protein for corn rootworm (Diabrotica spp.) control. DP915635 maize also expresses the phosphinothricin acetyltransferase (PAT) protein for tolerance to glufosinate herbicide and the phosphomannose isomerase (PMI) protein that was used as a selectable marker. A field study was conducted at ten sites in the United States and Canada during the 2019 growing season. Of the 11 agronomic endpoints that were evaluated, two of them (early stand count and days to flowering) were statistically significant compared with the control maize based on unadjusted p-values; however, these differences were not significant after FDR-adjustment of p-values. Composition analytes from DP915635 maize grain and forage (proximates, fiber, minerals, amino acids, fatty acids, vitamins, anti-nutrients, and secondary metabolites) were compared to non-GM near-isoline control maize (control maize) and non-GM commercial maize (reference maize). Statistically significant differences were observed for 7 of the 79 compositional analytes (16:1 palmitoleic acid, 18:0 stearic acid, 18:1 oleic acid, 18:2 linoleic acid, 24:0 lignoceric acid, methionine, and α-tocopherol); however, these differences were not significant after FDR-adjustment. Additionally, all of the values for composition analytes fell within the range of natural variation established from the in-study reference range, literature range, and/or tolerance interval. These results demonstrate that DP915635 is agronomically and compositionally comparable to non-GM maize represented by non-GM near-isoline control maize and non-GM commercial maize.
Asunto(s)
Aminoácidos , Zea mays , Estados Unidos , Zea mays/genética , Zea mays/metabolismo , Plantas Modificadas Genéticamente/metabolismo , Aminoácidos/metabolismo , Grano Comestible/metabolismo , Vitaminas/metabolismoRESUMEN
OBJECTIVE: The aim of the study is to identify lessons learned implementing JYNNEOS vaccination for laboratory workers exposed to orthopoxviruses such as mpox. METHODS: Workers at risk of laboratory exposure were offered vaccine in a carefully planned occupational health program. Vaccine was procured from the Centers for Disease Control and Prevention (CDC) Drug Service, which has special requirements. Reasons for accepting or declining vaccine and adverse effects were obtained by survey. RESULTS: Most workers accepted JYNNEOS, and occupational risk was the most commonly cited reason for acceptance. Most experienced mild local adverse effects. The administrative requirements of the Centers for Disease Control and Prevention Drug Service are documented. CONCLUSIONS: Occupational health programs caring for laboratory workers handling unusual biological agents require careful planning and coordination to facilitate access to vaccines that are not commercially available, anticipate and mitigate barriers to vaccination, and comply with special Centers for Disease Control and Prevention requirements.
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Orthopoxvirus , Vacuna contra Viruela , Vacunas , Humanos , VacunaciónRESUMEN
BACKGROUND: Urethral erosion secondary to a medical device-related pressure injury (MDRPI) is preventable, understudied, not well understood, and often overlooked. PURPOSE: This case report describes a patient who sustained an MDRPI secondary to indwelling urinary catheter placement for urinary retention. CASE STUDY: A 93-year-old man with prostate cancer and pneumonia received an indwelling urinary catheter for retention during a 2-week hospitalization. Upon his transfer to a rehabilitation facility, the patient's daughter informed staff that she had observed a 1-cm urethral erosion on the urinary meatus. Within a week, the penile erosion worsened to encircle the urinary meatus to 1.5 cm, and clinical signs of infection were present. Eventually, the patient was transferred to a hospice facility where he died. CONCLUSION: This case study demonstrates the need for increased training of health care professionals in identifying risk factors for MDRPI and managing such injuries to limit their devastating impact on the patient and family members.
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Lesiones por Aplastamiento , Úlcera por Presión , Retención Urinaria , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Catéteres de Permanencia/efectos adversos , Lesiones por Aplastamiento/etiología , Uretra/lesiones , Cateterismo Urinario/efectos adversos , Catéteres Urinarios/efectos adversos , Retención Urinaria/etiologíaRESUMEN
Event DP-Ø23211-2 (hereafter referred to as DP23211) maize expresses the DvSSJ1 double-stranded RNA (DvSSJ1 dsRNA) and the IPD072Aa protein, encoded by the ipd072Aa gene. DvSSJ1 dsRNA and the IPD072Aa protein each provide control of corn rootworms (Diabrotica spp.) when expressed in plants. As part of the environmental risk assessment (ERA), the potential hazard to non-target organisms (NTOs) exposed to the DvSSJ1 dsRNA and the IPD072Aa protein expressed in DP23211 maize was assessed. Worst-case estimated environmental concentrations (EECs) for different NTO functional groups (pollinators and pollen feeders, soil dwelling detritivores, predators and parasitoids, aquatic detritivores, insectivorous birds, and wild mammals) were calculated using worst-case assumptions. Several factors that reduce exposure to NTOs under more realistic environmental conditions were applied, when needed to provide more environmentally relevant EECs. Laboratory bioassays were conducted to assess the activity of DvSSJ1 dsRNA or the IPD072Aa protein against selected surrogate species, and margins of exposure (MOEs) were calculated by comparing the Tier I hazard study results to worst-case or refined EECs. Based on specificity and MOE values, DvSSJ1 dsRNA and the IPD072Aa protein expressed in DP23211 maize are not expected to be harmful to NTO populations at environmentally relevant concentrations.
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Escarabajos , ARN Bicatenario , Animales , Escarabajos/genética , Plantas Modificadas Genéticamente/genética , ARN Bicatenario/genética , Medición de Riesgo , Zea mays/genéticaRESUMEN
Despite over 25 years of safe deployment of genetically engineered crops, the number, complexity, and scope of regulatory studies required for global approvals continue to increase devoid of adequate scientific justification. Recently, there have been calls to further expand the scope of study and data requirements to improve public acceptance. However, increased regulation can actually generate consumer distrust due to the misperception that risks are high. We believe risk-disproportionate regulation as a means to advocate for acceptance of technology is counterproductive, even though some regulatory authorities believe it part of their mandate. To help avoid public distrust, the concept of regulatory transparency to demystify regulatory decision-making should be extended to clearly justifying specific regulatory requirements as: 1) risk-driven (i.e., proportionately addressing increased risk compared with traditional breeding), or 2) advocacy-driven (i.e., primarily addressing consumer concerns and acceptance). Such transparency in the motivation for requiring risk-disproportionate studies would: 1) lessen over-prescriptive regulation, 2) save public and private resources, 3) make beneficial products and technologies available to society sooner, 4) reduce needless animal sacrifice, 5) improve regulatory decision-making regarding safety, and 6) lessen public distrust that is generated by risk-disproportionate regulation.
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Productos Agrícolas , Fitomejoramiento , Animales , Productos Agrícolas/genética , Ingeniería Genética , Plantas Modificadas GenéticamenteRESUMEN
Event DP-2Ø2216-6 (referred to as DP202216 maize) was genetically modified to increase and extend the expression of the introduced zmm28 gene relative to endogenous zmm28 gene expression, resulting in plants with enhanced grain yield potential. The zmm28 gene expresses the ZMM28 protein, a MADS-box transcription factor. The safety assessment of DP202216 maize included an assessment of the potential hazard of the ZMM28 protein, as well as an assessment of potential unintended effects of the genetic insertion on agronomics, composition, and nutrition. The history of safe use (HOSU) of the ZMM28 protein was evaluated and a bioinformatics approach was used to compare the deduced amino acid sequence of the ZMM28 protein to databases of known allergens and toxins. Based on HOSU and the bioinformatics assessment, the ZMM28 protein was determined to be unlikely to be either allergenic or toxic to humans. The composition of DP202216 maize forage and grain was comparable to non-modified forage and grain, with no unintended effects on nutrition or food and feed safety. Additionally, feeding studies with broiler chickens and rats demonstrated a low likelihood of unintentional alterations in nutrition and low potential for adverse effects. Furthermore, the agronomics observed for DP202216 maize and non-modified maize were comparable, indicating that the likelihood of increased weediness or invasiveness of DP202216 maize in the environment is low. This comprehensive review serves as a reference for regulatory agencies and decision-makers in countries where authorization of DP202216 maize will be pursued, and for others interested in food, feed, and environmental safety.
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Pollos , Zea mays , Alérgenos , Alimentación Animal , Animales , Productos Agrícolas/genética , Plantas Modificadas Genéticamente , Ratas , Zea mays/genéticaRESUMEN
DP23211 maize was genetically modified (GM) to express DvSSJ1 double-stranded RNA and the IPD072Aa protein for control of corn rootworm (Diabrotica spp.). DP23211 maize also expresses the phosphinothricin acetyltransferase (PAT) protein for tolerance to glufosinate herbicide, and the phosphomannose isomerase (PMI) protein that was used as a selectable marker. A multi-location field trial was conducted during the 2018 growing season at 12 sites selected to be representative of the major maize-growing regions of the U.S. and Canada. Standard agronomic endpoints as well as compositional analytes from grain and forage (e.g., proximates, fibers, minerals, amino acids, fatty acids, vitamins, anti-nutrients, secondary metabolites) were evaluated and compared to non-GM near-isoline control maize (control maize) and non-GM commercial maize (reference maize). A small number of agronomic endpoints were statistically significant compared to the control maize, but were not considered to be biologically relevant when adjusted using the false discovery rate method (FDR) or when compared to the range of natural variation established from in-study reference maize. A small number of composition analytes were statistically significant compared to the control maize. These analytes were not statistically significant when adjusted using FDR, and all analyte values fell within the range of natural variation established from in-study reference range, literature range or tolerance interval, indicating that the composition of DP23211 maize grain and forage is substantially equivalent to conventional maize represented by non-GM near-isoline control maize and non-GM commercial maize.
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Grano Comestible , Zea mays/genética , Aminoácidos , Canadá , Plantas Modificadas GenéticamenteRESUMEN
The ZMM28 protein encoded by the zmm28 gene is endogenous to maize. DP202216 maize was genetically modified to increase and extend expression of the zmm28 gene relative to native zmm28 gene expression, resulting in plants with enhanced grain yield potential. Evaluation of the history of safe use (HOSU) is one component of the safety assessment framework for a newly expressed protein in a GM crop. The deduced amino acid sequence of the introduced ZMM28 protein in DP202216 maize is identical to the ZMM28 protein in nonmodified conventional maize. The ZMM28 protein has also been found in selected varieties of sweet corn kernels, and closely related proteins are found in other commonly consumed food crops. Concentrations of the ZMM28 protein in event DP202216 maize, conventional maize, and sweet corn are reported. This information supports, in part, the evaluation of HOSU, which can be leveraged in the safety assessment of the ZMM28 protein. Additional studies will be considered in the food and feed safety assessment of the DP202216 maize event.
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Proteínas de Plantas/química , Plantas Modificadas Genéticamente/química , Zea mays/química , Secuencia de Aminoácidos , Seguridad de Productos para el Consumidor , Inocuidad de los Alimentos , Alimentos Modificados Genéticamente , Humanos , Datos de Secuencia Molecular , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/metabolismo , Alineación de Secuencia , Zea mays/genética , Zea mays/metabolismoRESUMEN
DP202216 maize was genetically modified to increase and extend the expression of the zmm28 gene relative to native zmm28 gene expression, resulting in plants with enhanced grain yield potential. Standard nutritional and compositional parameters for maize grain and forage (e.g., proximates, fiber, minerals, amino acids, fatty acids, vitamins, anti-nutrients, secondary metabolites) from DP202216 maize were compared to grain and forage from non-modified near-isoline maize (control). Three amino acids (glycine, methionine, and serine) and two vitamins (vitamin B1 and vitamin B3) were statistically different between DP202216 and control maize grain but were not statistically different when adjusted using the false discovery rate method. These analyte values also fell within the ranges of natural variation of non-modified commercial maize varieties supporting that statistical differences were not biologically relevant. The composition of grain and forage from DP202216 maize is comparable to grain and forage from non-modified maize with a history of safe use.
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Grano Comestible/metabolismo , Plantas Modificadas Genéticamente/metabolismo , Zea mays/metabolismo , Aminoácidos/metabolismo , Niacinamida/metabolismo , Tiamina/metabolismoRESUMEN
As the global population continues to expand, utilizing an integrated approach to pest management will be critically important for food security, agricultural sustainability, and environmental protection. Genetically engineered (GE) crops that provide protection against insects and diseases, or tolerance to herbicides are important tools that complement a diversified integrated pest management (IPM) plan. However, despite the advantages that GE crops may bring for simplifying the approach and improving efficiency of pest and weed control, there are also challenges for successful implementation and sustainable use. This paper considers how several GE traits, including those that confer protection against insects by expression of proteins from Bacillus thuringiensis (Bt), traits that confer tolerance to herbicides, and RNAi-based traits that confer resistance to viral pathogens, can be key elements of a diversified IPM plan for several different crops in both developed and developing countries. Additionally, we highlight the importance of community engagement and extension, strong partnership between industry, regulators and farmers, and education and training programs, for achieving long-term success. By leveraging the experiences gained with these GE crops, understanding the limitations of the technology, and considering the successes and failures of GE traits in IPM plans for different crops and regions, we can improve the sustainability and versatility of IPM plans that incorporate these and future technologies.
RESUMEN
Genetically modified crops undergo extensive evaluation to characterize their food, feed and environmental safety prior to commercial introduction, using a well-established, science-based assessment framework. One component of the safety assessment includes an evaluation of each introduced trait, including its source organism, for potential adverse pathogenic, toxic and allergenic effects. Several Pseudomonas species have a history of safe use in agriculture and certain species represent a source of genes with insecticidal properties. The ipd072Aa gene from P. chlororaphis encodes the IPD072Aa protein, which confers protection against certain coleopteran pests when expressed in maize plants. P. chlororaphis is ubiquitous in the environment, lacks known toxic or allergenic properties, and has a history of safe use in agriculture and in food and feed crops. This information supports, in part, the safety assessment of potential traits, such as IPD072Aa, that are derived from this source organism.
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Proteínas Bacterianas/genética , Agentes de Control Biológico/farmacología , Productos Agrícolas/genética , Plantas Modificadas Genéticamente , Pseudomonas chlororaphis/genética , Insecticidas/farmacología , Filogenia , Zea mays/genéticaRESUMEN
As global populations continue to increase, agricultural productivity will be challenged to keep pace without overtaxing important environmental resources. A dynamic and integrated approach will be required to solve global food insecurity and position agriculture on a trajectory toward sustainability. Genetically modified (GM) crops enhanced through modern biotechnology represent an important set of tools that can promote sustainable agriculture and improve food security. Several emerging biotechnology approaches were discussed in a recent symposium organized at the 13th IUPAC International Congress of Pesticide Chemistry meeting in San Francisco, CA, USA. This paper summarizes the innovative research and several of the new and emerging technologies within the field of agricultural biotechnology that were presented during the symposium. This discussion highlights how agricultural biotechnology fits within the context of sustainable agriculture and improved food security and can be used in support of further development and adoption of beneficial GM crops.
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Biotecnología , Productos Agrícolas/genética , Plantas Modificadas Genéticamente/genética , Agricultura , Productos Agrícolas/química , Productos Agrícolas/inmunología , Productos Agrícolas/microbiología , Resistencia a la Enfermedad , Abastecimiento de Alimentos , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/microbiología , Plantas Modificadas Genéticamente/química , Plantas Modificadas Genéticamente/inmunología , Plantas Modificadas Genéticamente/microbiologíaRESUMEN
Maize (Zea mays) is a widely cultivated cereal that has been safely consumed by humans and animals for centuries. Transgenic or genetically engineered insect-resistant and herbicide-tolerant maize, are commercially grown on a broad scale. Event TC1507 (OECD unique identifier: DAS-Ø15Ø7-1) or the Herculex®(#) I trait, an insect-resistant and herbicide-tolerant maize expressing Cry1F and PAT proteins, has been registered for commercial cultivation in the US since 2001. A science-based safety assessment was conducted on TC1507 prior to commercialization. The safety assessment addressed allergenicity; acute oral toxicity; subchronic toxicity; substantial equivalence with conventional comparators, as well as environmental impact. Results from biochemical, physicochemical, and in silico investigations supported the conclusion that Cry1F and PAT proteins are unlikely to be either allergenic or toxic to humans. Also, findings from toxicological and animal feeding studies supported that maize with TC1507 is as safe and nutritious as conventional maize. Maize with TC1507 is not expected to behave differently than conventional maize in terms of its potential for invasiveness, gene flow to wild and weedy relatives, or impact on non-target organisms. These safety conclusions regarding TC1507 were acknowledged by over 20 regulatory agencies including United States Environment Protection Agency (US EPA), US Department of Agriculture (USDA), Canadian Food Inspection Agency (CFIA), and European Food Safety Authority (EFSA) before authorizing cultivation and/or food and feed uses. A comprehensive review of the safety studies on TC1507, as well as some benefits, are presented here to serve as a reference for regulatory agencies and decision makers in other countries where authorization of TC1507 is or will be pursued.
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Plantas Modificadas Genéticamente/efectos adversos , Zea mays/genética , Alimentación Animal/efectos adversos , Animales , Seguridad de Productos para el Consumidor , Inocuidad de los Alimentos , Humanos , Medición de Riesgo , Estados UnidosRESUMEN
PURPOSE OF REVIEW: The purpose of this study is to review the relevant literature concerning work-associated irritable larynx syndrome (WILS), a hyperkinetic laryngeal disorder associated with occupational irritant exposure. Clinical symptoms are variable and include dysphonia, cough, dyspnoea and globus pharyngeus. WILS is a clinical diagnosis and can be difficult to differentiate from asthma. Treatment options for WILS include medical and behavioural therapy. RECENT FINDINGS: Laryngeal-centred upper airway symptoms secondary to airborne irritants have been documented in the literature under a variety of diagnostic labels, including WILS, vocal cord dysfunction (VCD), laryngeal hypersensitivity and laryngeal neuropathy and many others. The underlying pathophysiology is as yet poorly understood; however, the clinical scenario suggests a multifactorial nature to the disorder. More recent literature indicates that central neuronal plasticity, inflammatory processes and psychological factors are all likely contributors. SUMMARY: Possible mechanisms for WILS include central neuronal network plasticity after noxious exposure and/or viral infection, inflammation (i.e. reflux disease) and intrinsic patient factors such a psychological state. Treatment is individualized and frequently includes one or more of the following: environmental changes in the workplace, GERD therapy, behavioural/speech therapy, psychotherapy counselling and neural modifiers.
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Enfermedades de la Laringe , Enfermedades Profesionales , Exposición Profesional/efectos adversos , Humanos , Enfermedades de la Laringe/etiología , Enfermedades de la Laringe/inmunología , Enfermedades de la Laringe/patología , Enfermedades de la Laringe/psicología , Enfermedades Profesionales/inmunología , Enfermedades Profesionales/patología , Enfermedades Profesionales/psicología , SíndromeRESUMEN
UNLABELLED: Pitch elevation surgery is most often indicated to assist male-to-female transgendered individuals seeking a more feminine voice quality. Behavioral therapy is primary management but if the desired voice quality is not achieved, surgery is offered. Procedures described that raise vocal pitch alter one or more of the main parameters known to physiologically control pitch; vocal fold tension, length, and mass. OBJECTIVE: Web formation with injection augmentation significantly raises vocal pitch in male-to-female transgendered individuals. STUDY DESIGN: Retrospective cohort study. This report describes the voice results after anterior web formation with injection augmentation to reduce vocal fold length in a series of 10 transgendered patients. METHODS: Retrospective review of male-to-female transgendered patients referred to St. Michaels Hospital Voice Clinic, Toronto, Canada for pitch elevation was carried out including demographic data, preoperative and postoperative acoustic data and videostroboscopic evaluation. RESULTS: Comparison between preoperative to postoperative acoustic measures demonstrated a mean increase in fundamental frequency of 110 Hz after web formation. Perturbation measures and pitch range were unchanged from before surgery to after surgery. CONCLUSION: This novel modification for endoscopic anterior web formation has been shown to be a successful procedure for permanent elevation of pitch with little or no morbidity.
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Feminización , Glotis/cirugía , Laringoscopía , Procedimientos de Reasignación de Sexo/métodos , Acústica del Lenguaje , Personas Transgénero , Calidad de la Voz , Acústica , Adulto , Femenino , Glotis/fisiología , Humanos , Laringoscopía/efectos adversos , Masculino , Persona de Mediana Edad , Ontario , Percepción de la Altura Tonal , Estudios Retrospectivos , Procedimientos de Reasignación de Sexo/efectos adversos , Medición de la Producción del Habla , Estroboscopía , Resultado del Tratamiento , Grabación en VideoRESUMEN
The manipulation of the RNA interference pathway using small interfering RNA (siRNA) has become the most frequently used gene silencing method. However, siRNA delivery into primary cells, especially primary macrophages, is often considered challenging. Here we report the investigation of the suitability of two methodologies: transient transfection and electroporation, to deliver siRNA targeted against the putative immunomodulatory gene Mediterranean fever (MEFV) into primary bovine monocyte-derived macrophages (bMDM). Eleven commercial transfection reagents were investigated with variable results with respect to siRNA uptake, target gene knock-down, cell toxicity and type I interferon (IFN) response induction. Three transfection reagents: Lipofectamine 2000, Lipofectamine RNAiMAX and DharmaFECT 3, were found to consistently give the best results. However, all the transfection reagents tested induced an IFN response in the absence of siRNA, which could be minimized by reducing the transfection reagent incubation period. In addition, optimized siRNA delivery into bMDM by electroporation achieved comparable levels of target gene knock-down as transient transfection, without a detectable IFN response, but with higher levels of cell toxicity. The optimized transient transfection and electroporation methodologies may provide a starting point for optimizing siRNA delivery into macrophages derived from other species or other cells considered difficult to investigate with siRNA.
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Electroporación/veterinaria , Macrófagos/inmunología , ARN Interferente Pequeño/administración & dosificación , ARN Interferente Pequeño/genética , Transfección/veterinaria , Animales , Bovinos , Proteínas del Citoesqueleto/genética , Proteínas del Citoesqueleto/inmunología , Femenino , Técnicas de Silenciamiento del Gen , Marcación de Gen/veterinaria , Pirina , Interferencia de ARNRESUMEN
Cellular damage from ionizing radiation (IR) is in part due to DNA damage and reactive oxygen species, which activate DNA damage response (DDR) and cytokine signaling pathways, including the ataxia telangiectasia mutated (ATM) and transforming growth factor (TGF)ß/Smad pathways. Using classic double-strand breaks (DSBs) markers, we studied the roles of Smad proteins in DDR and the crosstalk between TGFß and ATM pathways. We observed co-localization of phospho-Smad2 (pSmad2) and Smad7 with DSB repair proteins following low and high linear energy transfer (LET) radiation in human fibroblasts and epithelial cells. The decays of both foci were similar to that of γH2AX foci. Irradiation with high LET particles induced pSmad2 and Smad7 foci tracks indicating the particle trajectory through cells. pSmad2 foci were absent in S phase cells, while Smad7 foci were present in all phases of cell cycle. pSmad2 (but not Smad7) foci were completely abolished when ATM was depleted or inactivated. In contrast, a TGFß receptor 1 (TGFßR1) inhibitor abrogated Smad7, but not pSmad2 foci at DSBs sites. In summary, we suggest that Smad2 and Smad7 contribute to IR-induced DSB signaling in an ATM or TGFßR1-dependent manner, respectively.
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Proteínas de Ciclo Celular/fisiología , Roturas del ADN de Doble Cadena , Proteínas de Unión al ADN/fisiología , Proteínas Serina-Treonina Quinasas/fisiología , Proteína Smad2/metabolismo , Proteína smad7/metabolismo , Factor de Crecimiento Transformador beta/fisiología , Proteínas Supresoras de Tumor/fisiología , Factor de Transcripción Activador 2 , Proteínas de la Ataxia Telangiectasia Mutada , Línea Celular , Histonas/metabolismo , Humanos , Cinética , Transferencia Lineal de Energía , Fosforilación , Radiación Ionizante , Proteína Smad2/análisis , Proteína smad3/análisis , Proteína smad3/metabolismo , Proteína smad7/análisisRESUMEN
Atrazine, a broad-leaf herbicide, has been used widely to control weeds in corn and other crops for several decades and its extensive used has led to widespread contamination of soils and water bodies. Phytoremediation with switchgrass and other native prairie grasses is one strategy that has been suggested to lessen the impact of atrazine in the environment. The goal of this study is to characterize: (1) the uptake of atrazine into above-ground switchgrass biomass; and (2) the degradation and transformation of atrazine over time. A fate study was performed using mature switchgrass columns treated with an artificially-created agricultural runoff containing 16 ppm atrazine. Soil samples and above-ground biomass samples were taken from each column and analyzed for the presence of atrazine and its chlorinated metabolites. Levels of atrazine in both soil and plant material were detectable through the first 2 weeks of the experiment but were below the limit of detection by Day 21. Levels of deethylatrazine (DEA) and didealkylatrazine (DDA) were detected in soil and plant tissue intermittently over the course of the study, deisopropylatrazine (DIA) was not detected at any time point. A radiolabel study using [(14)C]atrazine was undertaken to observe uptake and degradation of atrazine with more sensitivity. Switchgrass columns were treated with a 4 ppm atrazine solution, and above-ground biomass samples were collected and analyzed using HPLC and liquid scintillation counting. Atrazine, DEA, and DIA were detected as soon as 1d following treatment. Two other metabolites, DDA and cyanuric acid, were detected at later time points, while hydroxyatrazine was not detected at all. The percentage of atrazine was observed to decrease over the course of the study while the percentages of the metabolites increased. Switchgrass plants appeared to exhibit a threshold in regard to the amount of atrazine taken up by the plants; levels of atrazine in leaf material peaked between Days 3 and 4 in both studies.