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2.
Curr Psychol ; : 1-11, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-35013656

RESUMO

In recent years, viral challenges on the Internet have become a very frequent phenomenon. These allude to the actions that are proposed to Internet users to record themselves performing a challenge and disseminate it on different online platforms so that other users will also perform it. Despite its rapid expansion, there is no evidence of any validated assessment tool of this phenomenon. To meet this need, the Viral Internet Challenges Scale (VICH-S) was designed. The main objective of this study was to establish the psychometric properties of this scale, the prevalence of different types of challenges (social, solidary, and dangerous), as well as the single or conjoint performance of these types of challenges using the VICH-S. Furthermore, the construct validity of the scale was tested with these variables: Fear of Missing Out, Loss of Connection (nomophobia), Self-Online, and Emotional Attention Online. Participants were 417 preadolescents (41.2% boys) with age ranging from 10 to 14 years. Exploratory factor analysis of the VICH-S scale revealed the existence of two factors: Challenge Satisfaction and Social Motivation. Convergent validity indicators showed positive and significant correlations between these two dimensions and the Fear of Missing Out, Loss of Connection (nomophobia), Self-Online, and Emotional Attention Online. The most frequent challenges were social challenges (80.3%), followed by solidary (20.6%) and dangerous challenges (7.7%). This study has relevant implications, as the VICH-S presents adequate psychometric properties to evaluate this barely explored and growing phenomenon of viral challenges on the Internet in preadolescence.

3.
J Prev Med Hyg ; 61(1): E9-E14, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32490263

RESUMO

INTRODUCTION: Hand hygiene is crucial to prevent cross infection. Healthcare students are in a prime position to learn hand hygiene skills. The aim of this study was to analyze hand hygiene behavioral intentions of healthcare students before and after contact with the patient and to compare the knowledge of and attitude towards hand hygiene between medical and nursing students. METHODS: In a descriptive survey research design, convenience selection of a sample of medical students (n=657) and nursing students (n=303) was done from modules taught by the Department of Preventive Medicine and Public Health in both Medicine and Nursing undergraduate degrees in four Spanish universities. The hand hygiene Questionnaire, a validated instrument to evaluate behavior, knowledge, and attitudes, was used. RESULTS: A significantly lower percentage of students reported always or almost always carrying out hand hygiene before contact with the patient or invasive procedures in comparison to the percentage complying after contact with secretions or with the patient. Although hand hygiene knowledge appears acceptable, its importance is not sufficiently valued. CONCLUSIONS: There are deficiencies in behavioral intention, knowledge, and attitudes related to hand hygiene in medical and nursing students. Better results are observed among nursing students, especially those who have received specific training.


Assuntos
Higiene das Mãos , Conhecimentos, Atitudes e Prática em Saúde , Intenção , Estudantes de Medicina , Estudantes de Enfermagem , Adolescente , Adulto , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Espanha , Adulto Jovem
4.
Insect Mol Biol ; 29(4): 373-380, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32249467

RESUMO

The implementation of Integrated Pest Management in current agricultural practice is a convenient and very effective strategy to keep pest populations under control. The use of biological control agents, such as Phytoseiulus persimilis, is key for the success of such an approach. This predatory mite is widely used as it is very effective for controlling Tetranychus urticae, one of the most devastating crop pests. Here, we identify several mutations located in the voltage-gated sodium channel (VGSC) of commercially sourced P. persimilis that correlate with a reduced susceptibility to the pyrethroid deltamethrin. We found that the mites sourced from two different biocontrol product companies have intrinsic genotypic differences that correlate with their phenotype when tested with different concentrations of deltamethrin. Mites from Syngenta Bioline, carrying the mutations M918L and A1536T, were able to survive deltamethrin concentrations of up to 10 ppm, while the mites from Koppert Biological Systems, with the combination M918L, L925V and S1539T, survived treatment with 40 ppm. All of the point mutations identified in the predatory mite samples are located in a particular region of the VGSC, previously proposed as the binding site for this family of pesticides and identified as a 'hot spot' for resistance.


Assuntos
Proteínas de Artrópodes/genética , Resistência a Medicamentos/genética , Mutação , Nitrilas/farmacologia , Piretrinas/farmacologia , Tetranychidae/genética , Canais de Sódio Disparados por Voltagem/genética , Acaricidas/farmacologia , Sequência de Aminoácidos , Animais , Proteínas de Artrópodes/metabolismo , Sequência de Bases , Mutação Puntual , Alinhamento de Sequência , Tetranychidae/metabolismo , Canais de Sódio Disparados por Voltagem/metabolismo
5.
Neotrop Entomol ; 48(6): 949-956, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31463776

RESUMO

To further the use of local parasitoids to control the spotted wing drosophila suzukii (Matsumura) in Mexico, three treatments were implemented by sextuplicate in commercial berry fields of Colima and Jalisco from June 2017 to May 2018: single release of Trichopria drosophilae Perkins (pupal parasitoid), combined release of T. drosophilae + Leptopilina boulardi Barbotin, Carton & Kelner-Pillault (larval parasitoid), and a no release control. Compared with the no release sites, parasitism by T. drosophilae increased 4 and 4.1-fold at the single and combined release sites, respectively, and parasitism of L. boulardi increased 2.8-fold at the sites where it was evaluated. Additionally, it was registered a 50 and 55% reduction of D. suzukii at the sites with single and combined releases, respectively; in other words, supplementing T. drosophilae with L. boulardi provided little benefit compared with the release of T. drosophilae alone. These results indicate that single release of local T. drosophilae is a more cost-effective option to reduce D. suzukii populations, and that such activity can contribute significantly to the phytosanitary management of this invasive pest.


Assuntos
Drosophila/parasitologia , Controle Biológico de Vetores/métodos , Vespas/fisiologia , Animais , México , Pupa/parasitologia , Rubus
6.
Qual Life Res ; 27(10): 2609-2618, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29881894

RESUMO

PURPOSE: Health-related quality of life (HRQoL) is a well-known construct that refers to a state of complete physical, mental, and social well-being. Its relationship with multiple forms of violence, including bullying, has been widely explored, but this is not the case for cyberbullying. The main objective is to analyze how HRQoL varies depending on the role played in cyberbullying, its temporal stability, and gender and age differences. METHOD: An analytical and longitudinal study was conducted at two temporal moments. At Time 1 (December 2015), 920 Spanish students aged between 11 and 18 years participated (Mage = 13.36, SD = 1.83: 48.9% boys and 51.1% girls). At Time 2 (April 2016), there were 313 participants (Mage 12.81 years, SD = 1.59: 53.4% boys and 46.6% girls). We used the Cyberbullying Test (technological scale) and the Spanish version of the KIDSCREEN-52. RESULTS: Cybervictims and cyberbully-victims present worse scores in all dimensions of the KIDSCREEN-52 (p < .001), compared to cyberbystanders or uninvolved individuals. There are gender differences only in cyberaggression and cyberbystanding. There are significant inverse correlations between all the dimensions of the KIDSCREEN-52 and cybervictimization, with Bullying (r = - .603, p < .001), Mood (r = - .329, p < .001), and School environment (r = - .327, p < .001) being particularly relevant. There were statistically significant differences between T1 and T2 for cyberbystanding (lower scores at T2). CONCLUSION: Cybervictims and cyberbully-victims have worse quality of life in all the dimensions than uninvolved individuals, especially in Psychological well-being, School environment, and Bullying.


Assuntos
Vítimas de Crime/psicologia , Cyberbullying/psicologia , Qualidade de Vida/psicologia , Adolescente , Comportamento do Adolescente/psicologia , Criança , Feminino , Humanos , Internet , Estudos Longitudinais , Masculino , Psicometria/métodos , Estudantes/psicologia , Inquéritos e Questionários
7.
Stress ; 17(2): 149-56, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24351081

RESUMO

Spanish medical graduates who apply for a medical specialty training position (MIR) must take an examination that will shape their future personal and professional lives. Preparation for the test represents an important stressor that persists for several months. The aim of this study was to elucidate the stress pattern of this group and evaluate possible changes in the circadian rhythm of cortisol release in medical graduates preparing for this test. A repeated-measures longitudinal study was performed, measuring the salivary cortisol concentrations in 36 medical graduates (13 males and 23 females; mean age of 24.2 years) on five sampling days. Five cortisol samples were collected from 07:00 to 21:00 h in order to monitor changes in the circadian rhythm. On all sampling days (except on the day of the official examination), anxiety and psychological stress were evaluated with the Spanish versions of the State-Trait Anxiety Inventory (STAI) and the Perceived Stress Scale (PSS). During the study period, participants showed higher levels of anxiety than the Spanish reference population as well as a progressive increase in self-perceived stress. A significant increase in salivary cortisol concentration was observed in both chronic (study and examination preparation) and acute (examinations) situations. Our results suggest that the cortisol awakening response (CAR) may be a good indicator of anticipatory stress but is unaffected by long-term examination preparation. Comparison of results between the official examination day and the mock examination days yielded evidence that learning may modulate the behavior of the hypothalamic-pituitary-adrenal axis.


Assuntos
Avaliação Educacional , Hidrocortisona/análise , Ansiedade de Desempenho/metabolismo , Saliva/química , Estresse Psicológico/metabolismo , Estudantes de Medicina/psicologia , Adulto , Antecipação Psicológica , Ritmo Circadiano , Feminino , Humanos , Hidrocortisona/metabolismo , Sistema Hipotálamo-Hipofisário/fisiopatologia , Masculino , Medicina , Ansiedade de Desempenho/etiologia , Inventário de Personalidade , Sistema Hipófise-Suprarrenal/fisiopatologia , Índice de Gravidade de Doença , Espanha , Estresse Psicológico/etiologia , Inquéritos e Questionários , Adulto Jovem
8.
Environ Technol ; 32(11-12): 1383-91, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21970180

RESUMO

Soils collected from five locations in the argan forest (an endemic plant) in Morocco were used to form the first collection of Bacillus thuringiensis (Bt) strains from this area (58 strains). Here we found that the argan forest is a major source of Bt, as 90.62% of the samples contained Bt strains. These strains produced mainly spherical or irregular crystals that in some cases remained adhered to the spore after cell lysis. There was no strain producing bipyramidal crystals, suggesting the absence of strains bearing crv1 genes. This was confirmed by PCR analysis using eight primer pairs that can potentially detect 13 different groups of cry and cyt genes. Strains containing cry7/8 were the most abundant (25.53%), followed by strains harbouring cry9A (14.89%), cry11 (8.51%) and cry4 (4.25%). The mixtures of spores and crystals as well as culture supernatants were assayed for toxicity towards Ceratitis capitata (Medfly), showing up to 30% mortality. Our findings suggest that the argan region is a suitable target for future and wider screening programmes looking for strains bearing toxins or combinations of them to develop more efficient Bt-based formulates.


Assuntos
Bacillus thuringiensis/fisiologia , Proteínas de Bactérias/química , Microbiologia do Solo , Animais , Bacillus thuringiensis/genética , Bacillus thuringiensis/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/química , Toxinas Bacterianas/genética , Toxinas Bacterianas/metabolismo , Ceratitis capitata/crescimento & desenvolvimento , Ceratitis capitata/microbiologia , Eletroforese em Gel de Poliacrilamida , Inseticidas/química , Inseticidas/metabolismo , Microscopia de Contraste de Fase , Marrocos , Reação em Cadeia da Polimerase , Sapotaceae
9.
J Microbiol Biotechnol ; 19(8): 749-59, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19734711

RESUMO

A survey of Bacillus thuringiensis (Berliner) strains isolated from Spanish citrus orchards has been performed, and the strains were tested for insecticidal activity against the Mediterranean fruit fly Ceratitis capitata (Wiedemann), a key citrus pest in Spain. From a total of 150 environmental samples, 376 isolates were selected, recording a total B. thuringiensis index of 0.52. The collection was characterized by means of phase-contrast microscopy, SDS-PAGE, and PCR analysis with primer pairs detecting toxin genes cry1, cry2, cry3, cry4, cry5, cry7, cry8, cry9, cry10, cry11, cry12, cry14, cry17, cry19, cry21, cry27, cry39, cry44, cyt1, and cyt2. Diverse crystal inclusion morphologies were identified: bipyramidal (45%), round (40%), adhered to the spore (7%), small (5%), and irregular (3%). SDSPAGE of spore-crystal preparations revealed 39 different electrophoresis patterns. All primer pairs used in PCR tests gave positive amplifications in strains of our collection, except for primers for detection of cry3, cry19, cry39, or cry44 genes. Strains containing cry1, cry2, cry4, and cry27 genes were the most abundant (48.7%, 46%, 11.2%, and 8.2% of the strains, respectively). Ten different genetic profiles were found, although a total of 109 strains did not amplify with the set of primers used. Screening for toxicity against C. capitata adults was performed using both spore-crystal and soluble fractions. Mortality levels were less than 30%. We have developed a large and diverse B. thuringiensis strain collection with huge potential to control several agricultural pests; however, further research is needed to find out Bt strains active against C. capitata.


Assuntos
Bacillus thuringiensis/isolamento & purificação , Proteínas de Bactérias/farmacologia , Ceratitis capitata/efeitos dos fármacos , Citrus/microbiologia , Endotoxinas/farmacologia , Proteínas Hemolisinas/farmacologia , Inseticidas/farmacologia , Controle Biológico de Vetores/métodos , Animais , Bacillus thuringiensis/química , Bacillus thuringiensis/citologia , Bacillus thuringiensis/genética , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Biodiversidade , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Eletroforese em Gel de Poliacrilamida , Endotoxinas/química , Endotoxinas/genética , Proteínas Hemolisinas/química , Proteínas Hemolisinas/genética , Inseticidas/química , Microscopia de Contraste de Fase , Reação em Cadeia da Polimerase , Espanha
10.
Anal Bioanal Chem ; 387(6): 2199-205, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17205269

RESUMO

In the present work we study the use of near-infrared spectroscopy (NIRS) technology together with a remote reflectance fibre-optic probe for the analysis of major (Ca, K, P) and minor (Fe, Mn, Na, Zn) elements, protein and moisture in alfalfa. The method allows immediate analysis of the alfalfa without prior sample treatment or destruction through direct application of the fibre-optic probe on ground samples in the case of the mineral composition and on-ground and compacted (baled) samples in the case of protein and humidity. The regression method employed was modified partial least-squares (MPLS). The calibration results obtained using samples of alfalfa allowed the determination of Ca, K, P, Fe, Mn, Na and Zn, with a standard error of prediction (SEP(C)) and a correlation coefficient (RSQ) expressed in mg/kg of alfalfa of 1.37x10(3) and 0.878 for Ca, 1.10x10(3) and 0.899 for K, 227 and 0.909 for P, 103 and 0.948 for Fe, 5.1 and 0.843 for Mn, 86.2 and 0.979 for Na, and of 1.9 and 0.853 for Zn, respectively. The SEP(C) and RSQ values (in %) for protein and moisture in ground samples were 0.548 and 0.871 and 0.150 and 0.981, respectively; while in the compacted samples they were 0.564 and 0.826 and 0.262 and 0.935, respectively. The prediction capacity of the model and the robustness of the method were checked in the external validation in alfalfa samples of unknown composition, and the results confirmed the suitability of the method.


Assuntos
Medicago sativa , Minerais/análise , Proteínas de Plantas/análise , Espectroscopia de Luz Próxima ao Infravermelho/instrumentação , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Água/análise , Calibragem , Medicago sativa/química
11.
J Invertebr Pathol ; 90(1): 51-4, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15913643

RESUMO

Toxicity and larval growth inhibition of 11 insecticidal proteins of Bacillus thuringiensis were evaluated against neonate larvae of Helicoverpa armigera, a major pest of important crops in Spain and other countries, by a whole-diet contamination method. The most active toxins were Cry1Ac4 and Cry2Aa1, with LC50 values of 3.5 and 6.3 microg/ml, respectively. At the concentrations tested, Cry1Ac4, Cry2Aa1, Cry9Ca, Cry1Fa1, Cry1Ab3, Cry2Ab2, Cry1Da, and Cry1Ja1, produced a significant growth inhibition, whereas Cry1Aa3, Cry1Ca2, and Cry1Ea had no effect.


Assuntos
Bacillus thuringiensis/metabolismo , Endotoxinas/metabolismo , Endotoxinas/intoxicação , Lepidópteros/efeitos dos fármacos , Controle Biológico de Vetores/métodos , Animais , Larva/efeitos dos fármacos , Lepidópteros/crescimento & desenvolvimento , Espanha
12.
Meat Sci ; 69(2): 243-8, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22062814

RESUMO

A near infrared spectrometer equipped with a standard 210/210 bundle remote reflectance fibre-optic probe, with a 5×5 cm quartz window type, was used for the determination of fatty acids in the Longissimus dorsi muscle of Iberian breed swine. The fatty acids C14:0, C16:0, C16:1, C17:0, C17:1, C18:0, C18:1, C18:2, C18:3, Σpolyunsaturated, Σmonounsaturated and Σsaturated were determined in samples of intramuscular fat from Iberian breed swine by direct application of the fibre-optic probe onto the loin sample, with no treatment or manipulation of the sample. The regression method employed was modified partial least squares. The calibration results using the fibre-optic probe for 74 loin samples had multiple correlation coefficients (RSQ) for C14:0, C16:0, C16:1, C17:0, C17:1, C18:0, C18:1, C18:2, C18:3, Σpolyunsaturated, Σmonounsaturated and Σsaturated acid of 0.785, 0.798, 0.788, 0.825, 0.762, 0.765, 0.696, 0.859, 0.878, 0.807, 0.943, 0.858, respectively, and standard errors of prediction corrected for the same fatty acids (%) of 0.08, 0.63, 0.26, 0.02, 0.02, 0.51, 0,77, 0.64, 0.05, 1.06, 0.34, 0.70, respectively. The robustness of the method was checked by applying the fibre-optic probe to unknown samples of Iberian breed pork loin in a slaughterhouse, using 15 samples for the external validation.

13.
J Environ Monit ; 5(4): 547-9, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12948225

RESUMO

The aim of this study has been to use a global index to measure the air quality in the city, apart from individual assessment of the values of the concentrations of the different pollutants. We calculated the ORAQI with the data obtained at four air-pollution monitoring stations located in the city of Salamanca over the period between 1993 and 2001. For the calculations, SO2, PM10, NO2, CO and O3 were used as the most significant pollutants for the surroundings of the monitoring stations. The evolution of this index over 9 years is reported, and the repercussion of the most characteristic pollutants of each season of the year on the ORAQI along the whole period analysed is studied. The importance of the summer pollution in the characterisation of the least polluted surroundings was observed. At the most polluted sites, a decrease in the values corresponding to winter occurs, leading the ORAQI to take similar values along the whole year. In general, taking into account the surroundings of all the monitoring stations, the quality of the air to which the inhabitants of the city of Salamanca are exposed to can be said to be good.


Assuntos
Poluentes Atmosféricos/análise , Exposição Ambiental , Modelos Teóricos , Cidades , Humanos , Dióxido de Nitrogênio/análise , Oxidantes Fotoquímicos/análise , Ozônio/análise , Tamanho da Partícula , Estações do Ano , Espanha , Dióxido de Enxofre/análise
14.
Appl Environ Microbiol ; 67(12): 5729-34, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11722929

RESUMO

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 Cry1Ja shares binding sites with Cry1A toxins. We tested this hypothesis in six moth and butterfly species, each from a different family: Cacyreus marshalli (Lycaenidae), Lobesia botrana (Tortricidae), Manduca sexta (Sphingidae), Pectinophora gossypiella (Gelechiidae), P. xylostella (Plutellidae), and Spodoptera exigua (Noctuidae). Although the extent of competition varied among species, experiments with biotinylated Cry1Ja and radiolabeled Cry1Ac showed that Cry1Ja and Cry1Ac competed for binding sites in all six species. A recent report also indicates shared binding sites for Cry1Ja and Cry1A toxins in Heliothis virescens (Noctuidae). Thus, shared binding sites for Cry1Ja and Cry1A occur in all lepidopteran species tested so far.


Assuntos
Proteínas de Bactérias/metabolismo , Toxinas Bacterianas , Endotoxinas/metabolismo , Lepidópteros/metabolismo , Sequência de Aminoácidos , Animais , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/genética , Proteínas de Bactérias/toxicidade , Sítios de Ligação , Ligação Competitiva , Endotoxinas/genética , Endotoxinas/toxicidade , Proteínas Hemolisinas , Resistência a Inseticidas , Larva/metabolismo , Lepidópteros/efeitos dos fármacos , Dados de Sequência Molecular
15.
Appl Environ Microbiol ; 67(11): 5043-8, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11679324

RESUMO

The long-term benefit of insecticidal products based on Cry toxins, either in sprays or as transgenic crops, is threatened by the development of resistance by target pests. The models used to predict evolution of resistance to Cry toxins most often are monogenic models in which two alleles are used. Moreover, the high-dose/refuge strategy recommended for implementation with transgenic crops relies on the assumption that the resistance allele is recessive. Using selection experiments, we demonstrated the occurrence in a laboratory colony of diamondback moth of two different genes (either allelic or nonallelic) that confer resistance to Cry1Ab. At the concentration tested, resistance was dominant in one selection line and partially recessive in the other. Resistant insects from the two selection lines also differed in their cross-resistance patterns. The diamondback moth colony was derived from a field population from the Philippines, which originally showed a different resistance phenotype. This is the first time that an insect population has been directly shown to carry more than one gene conferring resistance to the same Cry toxin.


Assuntos
Proteínas de Bactérias/toxicidade , Toxinas Bacterianas , Endotoxinas/toxicidade , Variação Genética , Resistência a Inseticidas/genética , Mariposas/efeitos dos fármacos , Mariposas/genética , Controle Biológico de Vetores , Animais , Bacillus thuringiensis/metabolismo , Toxinas de Bacillus thuringiensis , Genes de Insetos , Proteínas Hemolisinas , Mariposas/fisiologia , Seleção Genética
16.
Appl Environ Microbiol ; 67(10): 4610-3, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11571163

RESUMO

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 strains against five B. thuringiensis toxins (Cry1Aa, Cry1Ab, Cry1Ac, Cry1Ca, and Cry1Da) using two bioassay methods. Tests of the LAB-V strain from The Netherlands in different laboratories using different bioassay methods yielded only minor differences in results. In contrast, side-by-side comparisons revealed major genetic differences in susceptibility between strains. Compared with the LAB-V strain, the ROTH strain from England was 17- to 170-fold more susceptible to Cry1Aa and Cry1Ac, respectively, whereas the LAB-PS strain from Hawaii was 8-fold more susceptible to Cry1Ab and 13-fold more susceptible to Cry1Da and did not differ significantly from the LAB-V strain in response to Cry1Aa, Cry1Ac, or Cry1Ca. The relative potencies of toxins were similar among LAB-V, ROTH, and LAB-PS, with Cry1Ab and Cry1Ac being most toxic and Cry1Da being least toxic. Therefore, before choosing a standard reference strain upon which to base comparisons, it is highly advisable to perform an analysis of variation in susceptibility among field and laboratory populations.


Assuntos
Proteínas de Bactérias/toxicidade , Toxinas Bacterianas , Endotoxinas/toxicidade , Mariposas/efeitos dos fármacos , Animais , Toxinas de Bacillus thuringiensis , Bioensaio , Proteínas Hemolisinas , Resistência a Inseticidas , Larva/efeitos dos fármacos , Mariposas/genética
17.
Biochem Mol Biol Int ; 45(5): 1011-20, 1998 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9739466

RESUMO

Cry proteins from Bacillus thuringiensis have insecticidal properties. The function of domains I and II has been described but domain III has so far eluded understanding. Domain III from Cry1Ab and Cry1Ac has been cloned, expressed in E. coli and injected to rabbits with the aid of characterizing them immunologically. Interestingly, polyclonal antibodies against Cry1Ab fragment did not recognize either the native Cry1Ab toxin or the Cry1Ac fragment while those against the latter did recognize either the native Cry1Ac toxin or the Cry1Ab protein fragment. A combination of information from sequence comparison and hydrophobicity profile indicates that these protein fragments possibly adopt different spatial dispositions within the respective toxins.


Assuntos
Bacillus thuringiensis/química , Proteínas de Bactérias/química , Toxinas Bacterianas/química , Endotoxinas/química , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Toxinas Bacterianas/genética , Toxinas Bacterianas/imunologia , Clonagem Molecular , Endotoxinas/genética , Endotoxinas/imunologia , Ensaio de Imunoadsorção Enzimática , Proteínas Hemolisinas , Estrutura Secundária de Proteína , Proteínas Recombinantes/química , Solubilidade
18.
J Ind Microbiol Biotechnol ; 19(3): 202-19, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9418060

RESUMO

Bacillus thuringiensis is a Gram-positive bacterium, widely used in agriculture as a biological pesticide. The biocidal activity mainly resides in a parasporal protein inclusion body, or crystal. The inclusion is composed of one or more types of delta-endotoxins (Cry and Cyt proteins). Cry proteins are selectively toxic to different species from several invertebrate phyla: arthropods (mainly insects), nematodes, flatworms and protozoa. The mode of action of the insecticidal proteins is still a matter of investigation; generally, the active toxin is supposed to bind specific membrane receptors on the insect midgut brush-border epithelium, leading to intestinal cell lysis and subsequent insect death by starvation or septicemia. The toxin-encoding cry genes have been extensively studied and expressed in a large number of prokaryotic and eukaryotic organisms. The expression of such genes in transgenic plants has provided a powerful alternative for crop protection.


Assuntos
Bacillus thuringiensis/fisiologia , Proteínas de Bactérias/biossíntese , Toxinas Bacterianas , Endotoxinas/biossíntese , Controle Biológico de Vetores , Proteínas Recombinantes/biossíntese , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/química , Proteínas de Bactérias/farmacologia , Endotoxinas/química , Endotoxinas/farmacologia , Proteínas Hemolisinas , Resistência a Inseticidas , Plantas Geneticamente Modificadas
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