Search results for "PLUT"
showing 10 items of 153 documents
Toxicological Impact of Rare Earth Elements (REEs) on the Reproduction and Development of Aquatic Organisms Using Sea Urchins as Biological Models
2022
The growing presence of lanthanides in the environment has drawn the attention of the scientific community on their safety and toxicity. The sources of lanthanides in the environment include diagnostic medicine, electronic devices, permanent magnets, etc. Their exponential use and the poor management of waste disposal raise serious concerns about the quality and safety of the ecosystems at a global level. This review focused on the impact of lanthanides in marine organisms on reproductive fitness, fertilization and embryonic development, using the sea urchin as a biological model system. Scientific evidence shows that exposure to lanthanides triggers a wide variety of toxic insults, includi…
The color of mourning in Rome
2012
El negro es el color del luto en la antigua Roma. La presencia de personas con vestidos blancos en los funerales debe ser interpretada como una exhibición del status jurídico de los asistentes al acto y no como una manifestación del luto. Black is the color of mourning in ancient Rome. The presence of people in white dresses in the funerals must be interpreted as an exhibition of the legal status of the participants in the act and not as a manifestation of the mourning.
Simulations of stellar/pulsar wind interaction along one full orbit
2012
The winds from a non-accreting pulsar and a massive star in a binary system collide forming a bow-shaped shock structure. The Coriolis force induced by orbital motion deflects the shocked flows, strongly affecting their dynamics. We study the evolution of the shocked stellar and pulsar winds on scales in which the orbital motion is important. Potential sites of non-thermal activity are investigated. Relativistic hydrodynamical simulations in two dimensions, performed with the code PLUTO and using the adaptive mesh refinement technique, are used to model interacting stellar and pulsar winds on scales ~80 times the distance between the stars. The hydrodynamical results suggest the suitable lo…
Integrative Model for Binding of Bacillus thuringiensis Toxins in Susceptible and Resistant Larvae of the Diamondback Moth (Plutella xylostella)
1999
ABSTRACT Insecticidal crystal proteins from Bacillus thuringiensis in sprays and transgenic crops are extremely useful for environmentally sound pest management, but their long-term efficacy is threatened by evolution of resistance by target pests. The diamondback moth ( Plutella xylostella ) is the first insect to evolve resistance to B. thuringiensis in open-field populations. The only known mechanism of resistance to B. thuringiensis in the diamondback moth is reduced binding of toxin to midgut binding sites. In the present work we analyzed competitive binding of B. thuringiensis toxins Cry1Aa, Cry1Ab, Cry1Ac, and Cry1F to brush border membrane vesicles from larval midguts in a susceptib…
Resistance to the Bacillus thuringiensis bioinsecticide in a field population of Plutella xylostella is due to a change in a midgut membrane receptor.
1991
The biochemical mechanism for resistance to Bacillus thuringiensis crystal proteins was studied in a field population of diamondback moths (Plutella xylostella) with a reduced susceptibility to the bioinsecticidal spray. The toxicity and binding characteristics of three crystal proteins [CryIA(b), CryIB, and CryIC] were compared between the field population and a laboratory strain. The field population proved resistant (greater than 200-fold compared with the laboratory strain) to CryIA(b), one of the crystal proteins in the insecticidal formulation. Binding studies showed that the two strains differ in a membrane receptor that recognizes CryIA(b). This crystal protein did not bind to the b…
Shared Binding Sites in Lepidoptera for Bacillus thuringiensis Cry1Ja and Cry1A Toxins
2001
ABSTRACT Bacillus thuringiensis toxins act by binding to specific target sites in the insect midgut epithelial membrane. The best-known mechanism of resistance to B. thuringiensis toxins is reduced binding to target sites. Because alteration of a binding site shared by several toxins may cause resistance to all of them, knowledge of which toxins share binding sites is useful for predicting cross-resistance. Conversely, cross-resistance among toxins suggests that the toxins share a binding site. At least two strains of diamondback moth ( Plutella xylostella ) with resistance to Cry1A toxins and reduced binding of Cry1A toxins have strong cross-resistance to Cry1Ja. Thus, we hypothesized that…
Variation in Susceptibility to Bacillus thuringiensis Toxins among Unselected Strains of Plutella xylostella
2001
ABSTRACT So far, the only insect that has evolved resistance in the field to Bacillus thuringiensis toxins is the diamondback moth ( Plutella xylostella ). Documentation and analysis of resistant strains rely on comparisons with laboratory strains that have not been exposed to B. thuringiensis toxins. Previously published reports show considerable variation among laboratories in responses of unselected laboratory strains to B. thuringiensis toxins. Because different laboratories have used different unselected strains, such variation could be caused by differences in bioassay methods among laboratories, genetic differences among unselected strains, or both. Here we tested three unselected st…
Global variation in the genetic and biochemical basis of diamondback moth resistance to Bacillus thuringiensis
1997
Insecticidal proteins from the soil bacterium Bacillus thuringiensis (Bt) are becoming a cornerstone of ecologically sound pest management. However, if pests quickly adapt, the benefits of environmentally benign Bt toxins in sprays and genetically engineered crops will be short-lived. The diamondback moth ( Plutella xylostella ) is the first insect to evolve resistance to Bt in open-field populations. Here we report that populations from Hawaii and Pennsylvania share a genetic locus at which a recessive mutation associated with reduced toxin binding confers extremely high resistance to four Bt toxins. In contrast, resistance in a population from the Philippines shows multilocus control, a …
Genetic and Biochemical Approach for Characterization of Resistance to Bacillus thuringiensis Toxin Cry1Ac in a Field Population of the Diamondback M…
2000
ABSTRACT Four subpopulations of a Plutella xylostella (L.) strain from Malaysia (F 4 to F 8 ) were selected with Bacillus thuringiensis subsp. kurstaki HD-1, Bacillus thuringiensis subsp. aizawai , Cry1Ab, and Cry1Ac, respectively, while a fifth subpopulation was left as unselected (UNSEL-MEL). Bioassays at F 9 found that selection with Cry1Ac, Cry1Ab, B. thuringiensis subsp. kurstaki , and B. thuringiensis subsp. aizawai gave resistance ratios of >95, 10, 7, and 3, respectively, compared with UNSEL-MEL (>10,500, 500, >100, and 26, respectively, compared with a susceptible population, ROTH). Resistance to Cry1Ac, Cry1Ab, B. thuringiensis subsp. kurstaki , and B. thuringiensis subsp…
Lack of Cry1Fa binding to the midgut brush border membrane in a resistant colony of Plutella xylostella moths with a mutaton in the ABCC2 locus
2012
ABSTRACT Previous studies reported “mode 1” Bacillus thuringiensis resistance in a colony of diamondback moths (NO-QA), and recently, this resistance has been mapped to an ABC transporter ( ABCC2 ) locus. We report the lack of binding of Cry1Fa to insects derived from this colony and compare our data with those from other insects with ABCC2 -associated resistance.