Search results for "Genetically Modified"
showing 10 items of 345 documents
A mathematical model of exposure of nontarget Lepidoptera to Bt-maize pollen expressing Cry1Ab within Europe
2010
Genetically modified (GM) maize MON810 expresses a Cry1Ab insecticidal protein, derived from Bacillus thuringiensis ( Bt ), toxic to lepidopteran target pests such as Ostrinia nubilalis . An environmental risk to non-target Lepidoptera from this GM crop is exposure to harmful amounts of Bt -containing pollen deposited on host plants in or near MON810 fields. An 11-parameter mathematical model analysed exposure of larvae of three non-target species: the butterflies Inachis io (L.), Vanessa atalanta (L.) and moth Plutella xylostella (L.), in 11 representative maize cultivation regions in four European countries. A mortality–dose relationship was integrated with a dose–distance relationship t…
Evaluating Resistance to Bt Toxin Cry1Ab by F<SUB>2</SUB> Screen in European Populations of Ostrinia nubilalis (Lepidoptera: Crambidae)
2010
ABSTRACT The large-scale cultivation of transgenic crops producing Bacillus thuringiensis (Bt) toxins have already lead to the evolution of Bt resistance in some pest populations targeted by these crops. We used the F2 screening method for further estimating the frequency of resistance alleles of the European corn borer, Ostrinia nubilalis (Hubner) (Lepidoptera: Crambidae), to Bt maize, Zea mays L., producing the CrylAb toxin. In France, Germany, and Italy, 784, 455, and 80 lines of European corn borer were screened for resistance to Mon810 maize, respectively. In Slovakia, 26 lines were screened for resistance to the CrylAb toxin. The cost of F2 screen performed in the four countries varie…
Genetic Engineering Strategies for Abiotic Stress Tolerance in Plants
2015
Crop plants are affected by a variety of abiotic stresses such as salinity, drought, extreme temperatures, and oxidative stress and cause a significant yield loss (more than 50 %). In the near future, these abiotic stresses might increase because of global climate change. Abiotic stresses lead to dehydration or osmotic stress through reduced availability of water for vital cellular functions and maintenance of turgor pressure and also result in high production of reactive oxygen species (ROS). Plants are evolved with various mechanisms such as changes in cellular and metabolic processes to cope with the stress condition. Recent developments in molecular genetics have contributed greatly to …
Polyamines in Developing Stress-Resistant Crops
2012
F.Marco,R.Alcazar,T.Altabella,P.Carrasco,SarvajeetSinghGill,NarendraTuteja,andA.F. TiburcioPolyamines (PAs) are small protonated compounds with key roles in plant devel-opmentandphysiologicalprocesses.PAsmayalsofunctionasstressmessengersinplant responses to different stress signals. Recent studies using exogenous appli-cation of polyamines and more contemporary genetic manipulation of polyaminelevelsincropsandmodelspeciespointtotheirinvolvementinstressprotection.Thedifferentmechanismsbywhichpolyaminesexerttheirfunctionsarepresentlybeingunraveledandinvolvedifferentmodesofactionthataresummarizedinthischapter.Polyamines are integrated with other stress-related hormone pathways, such asabscisic…
Putrescine accumulation in Arabidopsis thaliana transgenic lines enhances tolerance to dehydration and freezing stress
2011
Polyamines have been globally associated to plant responses to abiotic stress. Particularly, putrescine has been related to a better response to cold and dehydration stresses. It is known that this polyamine is involved in cold tolerance, since Arabidopsis thaliana plants mutated in the key enzyme responsible for putrescine synthesis (arginine decarboxilase, ADC; EC 4.1.1.19) are more sensitive than the wild type to this stress. Although it is speculated that the over-expression of ADC genes may confer tolerance, this is hampered by pleiotropic effects arising from the constitutive expression of enzymes from the polyamine metabolism. Here, we present our work using A. thaliana transgenic pl…
Agrobacterium tumefaciens-mediated genetic transformation of the cardenolide-producing plant Digitalis minor L.
2003
A repeatable transformation system has been established for Digitalis minor using Agrobacterium tumefaciens. Leaf explants from 30-day-old seedlings were inoculated with either EHA105 (carrying the nptII and gusA genes) or AGL1 (with the bar and gusA genes) strains. Among the tested factors influencing T-DNA transfer to plants, the EHA105 strain and the addition of acetosyringone to the co-culture medium increased transformation. The highest transformation efficiency (8.4%) was obtained when freshly isolated explants, soaked in a bacterial suspension with an OD 550 of 0.9, were subcultured on selection medium after a 4-day co-culture with the bacteria. Evidence of stable transgene integrati…
Regeneration of herbicide-tolerant black locust transgenic plants by SAAT
2003
A protocol based on SAAT (sonication-assisted Agrobacterium-mediated transformation) has been developed to obtain herbicide-resistant transgenic black locust (Robinia pseudoacacia L.) plants. Cotyledon explants were co-cultivated with Agrobacterium AGL1 strain carrying the pTAB16 plasmid (bar and gusA genes). The effects of bacterial concentration (OD550 of 0.3, 0.6, 0.8) and method of infection (sonication vs immersion) on bacterial delivery were determined by assaying cotyledons for transient beta-glucuronidase expression 3 days after infection. SAAT increases transient expression efficiency especially at an OD550 of 0.6. After determining bacterial concentration and infection method, oth…
NDST1 missense mutations in autosomal recessive intellectual disability.
2014
NDST1 was recently proposed as a candidate gene for autosomal recessive intellectual disability in two families. It encodes a bifunctional GlcNAc N-deacetylase/N-sulfotransferase with important functions in heparan sulfate biosynthesis. In mice, Ndst1 is crucial for embryonic development and homozygous null mutations are perinatally lethal. We now report on two additional unrelated families with homozygous missense NDST1 mutations. All mutations described to date predict the substitution of conserved amino acids in the sulfotransferase domain, and mutation modeling predicts drastic alterations in the local protein conformation. Comparing the four families, we noticed significant overlap in …
HSF1-controlled and age-associated chaperone capacity in neurons and muscle cells of C. elegans.
2010
Protein stability under changing conditions is of vital importance for the cell and under the control of a fine-tuned network of molecular chaperones. Aging and age-related neurodegenerative diseases are directly associated with enhanced protein instability. Employing C. elegans expressing GFP-tagged luciferase as a reporter for evaluation of protein stability we show that the chaperoning strategy of body wall muscle cells and neurons is significantly different and that both are differently affected by aging. Muscle cells of young worms are largely resistant to heat stress, which is directly mediated by the stress response controlled through Heat Shock Transcription Factor 1. During recover…
Shared midgut binding sites for Cry1A.105, Cry1Aa, Cry1Ab, Cry1Ac and Cry1Fa proteins from Bacillus thuringiensis in two important corn pests, Ostrin…
2013
First generation of insect-protected transgenic corn (Bt-corn) was based on the expression of Cry1Ab or Cry1Fa proteins. Currently, the trend is the combination of two or more genes expressing proteins that bind to different targets. In addition to broadening the spectrum of action, this strategy helps to delay the evolution of resistance in exposed insect populations. One of such examples is the combination of Cry1A.105 with Cry1Fa and Cry2Ab to control O. nubilalis and S. frugiperda. Cry1A.105 is a chimeric protein with domains I and II and the C-terminal half of the protein from Cry1Ac, and domain III almost identical to Cry1Fa. The aim of the present study was to determine whether the c…