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1.
Nucleic Acids Res ; 45(18): e158, 2017 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-28985360

RESUMO

The 'sandwich' binding format, which uses two reagents that can bind simultaneously to a given analyte, is the gold standard in diagnostics and many biochemical techniques. One of the bottlenecks in creating a sandwich assay is identifying pairs of reagents that bind non-competitively to the target. To bridge this gap, we invented Megaprimer Shuffling for Tandem Affinity Reagents (MegaSTAR) to identify non-competitive binding pairs of recombinant affinity reagents through phage-display. The key innovation in MegaSTAR is the construction of a tandem library, in which two reagents are randomly-displayed on the phage surface. This is accomplished by using a pool of 300-nucleotide long 'megaprimers', which code for previously-selected reagents, to prime second strand synthesis of a single-stranded DNA template and generate millions of pair-wise combinations. The tandem library is then affinity selected to isolate pairs that both reagents contribute to binding the target. As a proof-of-concept, we used MegaSTAR to identify pairs of fibronectin type III monobodies for three human proteins. For each target, we could identify between five and fifteen unique pairs and successfully used a single pair in a sandwich assay. MegaSTAR is a versatile tool for generating sandwich ELISA-grade and bispecific reagents.


Assuntos
Marcadores de Afinidade/metabolismo , Técnicas de Visualização da Superfície Celular/métodos , Domínios e Motivos de Interação entre Proteínas , Proteínas Recombinantes/metabolismo , Ensaio de Imunoadsorção Enzimática , Técnicas Genéticas , Ensaios de Triagem em Larga Escala/métodos , Humanos , Biblioteca de Peptídeos , Polimerização , Ligação Proteica , Proteínas Recombinantes/química
2.
BMC Biol ; 13: 49, 2015 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-26179401

RESUMO

BACKGROUND: Development and evaluation of new insect pest management tools is critical for overcoming over-reliance upon, and growing resistance to, synthetic, biological and plant-expressed insecticides. For transgenic crops expressing insecticidal proteins from the bacterium Bacillus thuringiensis ('Bt crops') emergence of resistance is slowed by maintaining a proportion of the crop as non-Bt varieties, which produce pest insects unselected for resistance. While this strategy has been largely successful, multiple cases of Bt resistance have now been reported. One new approach to pest management is the use of genetically engineered insects to suppress populations of their own species. Models suggest that released insects carrying male-selecting (MS) transgenes would be effective agents of direct, species-specific pest management by preventing survival of female progeny, and simultaneously provide an alternative insecticide resistance management strategy by introgression of susceptibility alleles into target populations. We developed a MS strain of the diamondback moth, Plutella xylostella, a serious global pest of crucifers. MS-strain larvae are reared as normal with dietary tetracycline, but, when reared without tetracycline or on host plants, only males will survive to adulthood. We used this strain in glasshouse-cages to study the effect of MS male P. xylostella releases on target pest population size and spread of Bt resistance in these populations. RESULTS: Introductions of MS-engineered P. xylostella males into wild-type populations led to rapid pest population decline, and then elimination. In separate experiments on broccoli plants, relatively low-level releases of MS males in combination with broccoli expressing Cry1Ac (Bt broccoli) suppressed population growth and delayed the spread of Bt resistance. Higher rates of MS male releases in the absence of Bt broccoli were also able to suppress P. xylostella populations, whereas either low-level MS male releases or Bt broccoli alone did not. CONCLUSIONS: These results support theoretical modeling, indicating that MS-engineered insects can provide a powerful pest population suppressing effect, and could effectively augment current Bt resistance management strategies. We conclude that, subject to field confirmation, MS insects offer an effective and versatile control option against P. xylostella and potentially other pests, and may reduce reliance on and protect insecticide-based approaches, including Bt crops.


Assuntos
Animais Geneticamente Modificados/genética , Brassica/parasitologia , Produtos Agrícolas/parasitologia , Resistência a Inseticidas , Mariposas/genética , Controle Biológico de Vetores/métodos , Transgenes , Animais , Bacillus thuringiensis/genética , Brassica/genética , Produtos Agrícolas/genética , Feminino , Engenharia Genética , Masculino , Mariposas/fisiologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/parasitologia
3.
Int J Mol Sci ; 16(10): 23587-603, 2015 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-26437402

RESUMO

Often when generating recombinant affinity reagents to a target, one singles out an individual binder, constructs a secondary library of variants, and affinity selects a tighter or more specific binder. To enhance the throughput of this general approach, we have developed a more integrated strategy where the "affinity maturation" step is part of the phage-display pipeline, rather than a follow-on process. In our new schema, we perform two rounds of affinity selection, followed by error-prone PCR on the pools of recovered clones, generation of secondary libraries, and three additional rounds of affinity selection, under conditions of off-rate competition. We demonstrate the utility of this approach by generating low nanomolar fibronectin type III (FN3) monobodies to five human proteins: ubiquitin-conjugating enzyme E2 R1 (CDC34), COP9 signalosome complex subunit 5 (COPS5), mitogen-activated protein kinase kinase 5 (MAP2K5), Splicing factor 3A subunit 1 (SF3A1) and ubiquitin carboxyl-terminal hydrolase 11 (USP11). The affinities of the resulting monobodies are typically in the single-digit nanomolar range. We demonstrate the utility of two binders by pulling down the targets from a spiked lysate of HeLa cells. This integrated approach should be applicable to directed evolution of any phage-displayed affinity reagent scaffold.


Assuntos
Cromatografia de Afinidade/métodos , Proteínas Recombinantes/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Anticorpos/metabolismo , Antígenos/metabolismo , Biotinilação , Calorimetria , Técnicas de Visualização da Superfície Celular , Células HeLa , Humanos , Indicadores e Reagentes , Cinética , Dados de Sequência Molecular , Estrutura Secundária de Proteína
4.
Cureus ; 15(10): e46955, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38022295

RESUMO

Cardiac lipomas are benign primary cardiac tumors that are most often asymptomatic and diagnosed incidentally. Cardiac magnetic resonance imaging (MRI) is the imaging modality of choice when aiming to characterize these tumors. A minority of cardiac lipomas are intramyocardial, which, when combined with the much more common post-infarction fatty metaplasia, makes diagnosing these lipomas very challenging. We review a case of intramyocardial lipoma in the distal interventricular septum that was initially detected on a low-dose computed tomography for lung cancer screening and the subsequent findings on cardiac MRI that made the diagnosis. Additionally, this case also helps to support the conservative management of intramyocardial lipomas that are more distal in the left ventricle and subsequently at lower risk for conduction arrhythmias.

5.
PLoS One ; 18(2): e0278466, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36812214

RESUMO

There have been over 621 million cases of COVID-19 worldwide with over 6.5 million deaths. Despite the high secondary attack rate of COVID-19 in shared households, some exposed individuals do not contract the virus. In addition, little is known about whether the occurrence of COVID-19 resistance differs among people by health characteristics as stored in the electronic health records (EHR). In this retrospective analysis, we develop a statistical model to predict COVID-19 resistance in 8,536 individuals with prior COVID-19 exposure using demographics, diagnostic codes, outpatient medication orders, and count of Elixhauser comorbidities in EHR data from the COVID-19 Precision Medicine Platform Registry. Cluster analyses identified 5 patterns of diagnostic codes that distinguished resistant from non-resistant patients in our study population. In addition, our models showed modest performance in predicting COVID-19 resistance (best performing model AUROC = 0.61). Monte Carlo simulations conducted indicated that the AUROC results are statistically significant (p < 0.001) for the testing set. We hope to validate the features found to be associated with resistance/non-resistance through more advanced association studies.


Assuntos
COVID-19 , Humanos , SARS-CoV-2 , Estudos Retrospectivos , Aprendizado de Máquina , Registros Eletrônicos de Saúde
6.
PLoS Negl Trop Dis ; 16(5): e0010315, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35576193

RESUMO

Establishment of novel mosquito control technologies such as the use of genetically engineered insects typically involves phased testing to generate robust data-sets that support its safe and effective use as a vector control tool. In this study, we demonstrate the ability of the transgenic self-limiting OX513A Aedes aegypti strain to suppress a wild type Ae. aegypti population in an outdoor containment facility in India. OX513A is a genetically engineered Ae. aegypti strain with a repressible dominant self-limiting gene. When male adult OX513A mate with wild female adults, a single copy of the self-limiting gene is inherited by all the progeny, leading to death of >95% of progeny during larval/pupal development. A wild-type population of Ae. aegypti was established and stabilized during a 14 week period in five paired field cage units, each consisting of control and treatment cages, followed by weekly releases of OX513A male adults to suppress the target population. The successive introductions of OX513A male adults led to a consistent decline in wild type numbers eventually resulting in the elimination of Ae. aegypti from all treated cages within 10 to 15 weeks of release. This study demonstrates that Ae. aegypti elimination may be a realistic and achievable target in relatively isolated environments.


Assuntos
Aedes , Febre Amarela , Aedes/genética , Animais , Feminino , Masculino , Controle de Mosquitos , Mosquitos Vetores/genética , Controle Biológico de Vetores/métodos
7.
Front Bioeng Biotechnol ; 10: 975786, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36394032

RESUMO

For more than 60 years, efforts to develop mating-based mosquito control technologies have largely failed to produce solutions that are both effective and scalable, keeping them out of reach of most governments and communities in disease-impacted regions globally. High pest suppression levels in trials have yet to fully translate into broad and effective Aedes aegypti control solutions. Two primary challenges to date-the need for complex sex-sorting to prevent female releases, and cumbersome processes for rearing and releasing male adult mosquitoes-present significant barriers for existing methods. As the host range of Aedes aegypti continues to advance into new geographies due to increasing globalisation and climate change, traditional chemical-based approaches are under mounting pressure from both more stringent regulatory processes and the ongoing development of insecticide resistance. It is no exaggeration to state that new tools, which are equal parts effective and scalable, are needed now more than ever. This paper describes the development and field evaluation of a new self-sexing strain of Aedes aegypti that has been designed to combine targeted vector suppression, operational simplicity, and cost-effectiveness for use in disease-prone regions. This conditional, self-limiting trait uses the sex-determination gene doublesex linked to the tetracycline-off genetic switch to cause complete female lethality in early larval development. With no female progeny survival, sex sorting is no longer required, eliminating the need for large-scale mosquito production facilities or physical sex-separation. In deployment operations, this translates to the ability to generate multiple generations of suppression for each mosquito released, while being entirely self-limiting. To evaluate these potential benefits, a field trial was carried out in densely-populated urban, dengue-prone neighbourhoods in Brazil, wherein the strain was able to suppress wild mosquito populations by up to 96%, demonstrating the utility of this self-sexing approach for biological vector control. In doing so, it has shown that such strains offer the critical components necessary to make these tools highly accessible, and thus they harbour the potential to transition mating-based approaches to effective and sustainable vector control tools that are within reach of governments and at-risk communities who may have only limited resources.

8.
BMC Genomics ; 12: 56, 2011 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-21261962

RESUMO

BACKGROUND: The whitefly Trialeurodes vaporariorum is an economically important crop pest in temperate regions that has developed resistance to most classes of insecticides. However, the molecular mechanisms underlying resistance have not been characterised and, to date, progress has been hampered by a lack of nucleotide sequence data for this species. Here, we use pyrosequencing on the Roche 454-FLX platform to produce a substantial and annotated EST dataset. This 'unigene set' will form a critical reference point for quantitation of over-expressed messages via digital transcriptomics. RESULTS: Pyrosequencing produced around a million sequencing reads that assembled into 54,748 contigs, with an average length of 965 bp, representing a dramatic expansion of existing cDNA sequences available for T. vaporariorum (only 43 entries in GenBank at the time of this publication). BLAST searching of non-redundant databases returned 20,333 significant matches and those gene families potentially encoding gene products involved in insecticide resistance were manually curated and annotated. These include, enzymes potentially involved in the detoxification of xenobiotics and those encoding the targets of the major chemical classes of insecticides. A total of 57 P450s, 17 GSTs and 27 CCEs were identified along with 30 contigs encoding the target proteins of six different insecticide classes. CONCLUSION: Here, we have developed new transcriptomic resources for T. vaporariorum. These include a substantial and annotated EST dataset that will serve the community studying this important crop pest and will elucidate further the molecular mechanisms underlying insecticide resistance.


Assuntos
Hemípteros/genética , Inseticidas/farmacologia , Animais , Biologia Computacional , Perfilação da Expressão Gênica , Hemípteros/efeitos dos fármacos , Proteínas de Insetos/genética , Resistência a Inseticidas/genética , Filogenia
9.
Respir Med Case Rep ; 26: 321-325, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30937281

RESUMO

Pulmonary vein stenosis (PVS) is a serious complication of radiofrequency ablation (RFA) for the treatment of atrial fibrillation. The prevalence of this complication was reported to be as high as 42% in 1999 when RFA was first implemented [1]. However, with improvements in operator technique including wide area circumferential ablation, antral isolation, and the use of intracardiac ultrasound, the incidence of symptomatic severe PVS following RFA ranges from 0% to 2.1% while the incidence of symptomatic pulmonary vein occlusion (PVO) following RFA was found to be 0.67% [2-8]. Despite a decrease in the incidence of clinically significant PVS following RFA, there have been increased reports of complications associated with PVS to include hemoptysis, scarring, lung infarction, and intraparenchymal hemorrhage [9]. Studies have shown that PVS is often misdiagnosed as pneumonia, pulmonary embolism, and lung cancer and as a result, patients are often subjected to unnecessary diagnostic procedures [2,10]. The current first line treatment for this condition is percutaneous balloon angioplasty with stenting; however, there are studies that have shown that there is a relatively high rate of restenosis despite optimal medical therapy [2-3,10,11]. Three case reports have described the use of lobectomy to treat patients with persistent respiratory symptoms in the setting of severe PVO with good outcomes [12-14]. We present a case of iatrogenic PVO and ipsilateral severe PVS following RFA who underwent attempted lobectomy for persistent exertional dyspnea and persistent hypoperfusion of the left upper lung lobe despite percutaneous intervention and six months of optimal medical therapy. The lobectomy was aborted due to the presence of a significant fibrothorax, and the patient continues to have significant exercise limitation despite participation in pulmonary rehabilitation.

10.
Insect Biochem Mol Biol ; 38(6): 634-44, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18510975

RESUMO

The two most damaging biotypes of Bemisia tabaci, B and Q, have both evolved strong resistance to the neonicotinoid insecticide imidacloprid. The major mechanism in all samples investigated so far appeared to be enhanced detoxification by cytochrome P450s monooxygenases (P450s). In this study, a polymerase chain reaction (PCR) technology using degenerate primers based on conserved P450 helix I and heme-binding regions was employed to identify P450 cDNA sequences in B. tabaci that might be involved in imidacloprid resistance. Eleven distinct P450 cDNA sequences were isolated and classified as members of the CYP4 or CYP6 families. The mRNA expression levels of all 11 genes were compared by real-time quantitative RT-PCR across nine B and Q field-derived strains of B. tabaci showing strong resistance, moderate resistance or susceptibility to imidacloprid. We found that constitutive over-expression (up to approximately 17-fold) of a single P450 gene, CYP6CM1, was tightly related to imidacloprid resistance in both the B and Q biotypes. Next, we identified three single-nucleotide polymorphic (SNP) markers in the intron region of CYP6CM1 that discriminate between the resistant and susceptible Q-biotype CYP6CM1 alleles (r-Q and s-Q, respectively), and used a heterogeneous strain to test for association between r-Q and resistance. While survivors of a low imidacloprid dose carried both the r-Q and s-Q alleles, approximately 95% of the survivors of a high imidacloprid dose carried only the r-Q allele. Together with previous evidence, the results reported here identify enhanced activity of P450s as the major mechanism of imidacloprid resistance in B. tabaci, and the CYP6CM1 gene as a leading target for DNA-based screening for resistance to imidacloprid and possibly other neonicotinoids in field populations.


Assuntos
Sistema Enzimático do Citocromo P-450/genética , Hemípteros/genética , Imidazóis , Inseticidas , Nitrocompostos , Alelos , Sequência de Aminoácidos , Animais , Sistema Enzimático do Citocromo P-450/metabolismo , DNA Complementar/química , Expressão Gênica , Hemípteros/enzimologia , Resistência a Inseticidas/genética , Dados de Sequência Molecular , Neonicotinoides , Fenótipo , Filogenia , Análise de Sequência de DNA
11.
Pest Manag Sci ; 64(11): 1106-10, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18798168

RESUMO

Neonicotinoid insecticides retain a crucial role within many chemical and integrated control strategies for the tobacco whitefly, Bemisia tabaci Gennadius, in spite of the establishment of potent and widespread resistance in many areas. Metabolic resistance mechanisms mediated by overexpression of P450-dependent monooxygenases have been implicated in neonicotinoid resistance in the two most prevalent B. tabaci biotypes. Further characterisation of resistance to the neonicotinoid imidacloprid in populations of both these B- and Q-types is reported.Expression of resistance to imidacloprid was age specific in B- and Q-type strains of B. tabaci. The highest observed resistance ratio at LC(50) expressed in prepupal nymphs was 13, compared with at least 580 in their adult counterparts. For all strains, resistance expressed in immatures was not sufficiently potent to compromise recommended imidacloprid application rates.Targeting neonicotinoids towards immature life stages of B. tabaci may circumvent the protection conferred by current mechanisms of resistance, simultaneously reducing the selection pressures imposed. However, such tactics may enhance the expression of existing resistance mechanisms in immatures, or promote the establishment of novel ones expressed in all life stages.


Assuntos
Hemípteros/crescimento & desenvolvimento , Imidazóis , Inseticidas , Nitrocompostos , Fatores Etários , Animais , Feminino , Resistência a Inseticidas , Neonicotinoides , Ninfa
12.
Pest Manag Sci ; 64(11): 1122-5, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18803175

RESUMO

BACKGROUND: Rice brown planthopper, Nilaparvata lugens Stål, is a primary insect pest of cultivated rice, and effective control is essential for economical crop production. Resistance to neonicotinoid insecticides, in particular imidacloprid, has been reported as an increasing constraint in recent years. In order to investigate the extent of resistance, 24 samples of N. lugens were collected from China, India, Indonesia, Malaysia, Thailand and Vietnam during 2005 and 2006. Their responses to two diagnostic doses of imidacloprid (corresponding approximately to the LC(95) and 5 x LC(95) of a susceptible strain) were examined. RESULTS: Ten of the 12 samples collected during 2005 were found to be susceptible to imidacloprid, but two late-season samples from India showed reduced mortality at both diagnostic doses. All 13 strains collected in 2006 showed reduced mortality at both doses when compared with the susceptible strain. Dose-response lines showed resistance in one of the most resistant field strains to be approximately 100-fold compared with the susceptible standard. CONCLUSION: The data demonstrate the development and spread of neonicotinoid resistance in N. lugens in Asia and support reports of reduced field efficacy of imidacloprid.


Assuntos
Hemípteros , Imidazóis , Inseticidas , Nitrocompostos , Animais , Ásia , Feminino , Geografia , Resistência a Inseticidas , Neonicotinoides
13.
Pest Manag Sci ; 64(1): 12-5, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17972303

RESUMO

BACKGROUND: B and Q biotypes of the whitefly, Bemisia tabaci (Gennadius), are generally regarded as the most significant given their global distribution and strong resistance to insecticides. Since these biotypes can coexist and differ markedly in their insecticide resistance profiles, a rapid but reliable means of discriminating between them would be a valuable complement to resistance monitoring and management programmes. Recently, PCR-based methods have been developed to determine the biotype status of B. tabaci populations. However, these require post-amplification procedures, which increase time and labour. RESULTS: The authors have developed an allelic discrimination real-time PCR assay using fluorescent dye-labelled probes to distinguish the B and Q biotypes. The assay targets a single nucleotide polymorphism (SNP) in the mitochondrial cytochrome oxidase I (mtCOI) gene. To evaluate the assay, DNA was extracted from individual whiteflies of six known biotype strains, and all scored correctly as either a B or Q biotype. As further validation, 72 individuals from field samples collected in different parts of the world were also tested by the assay. No failed reactions were observed, with all 72 samples scoring clearly as either the B or Q biotype. CONCLUSION: The development of this rapid and high-throughput assay has important potential for routine monitoring of B and Q biotypes on ornamental plants and for the screening of B. tabaci populations in countries where these biotypes are not yet established.


Assuntos
Alelos , Hemípteros/genética , Reação em Cadeia da Polimerase/métodos , Animais , Sequência de Bases , Complexo IV da Cadeia de Transporte de Elétrons/genética , Hemípteros/classificação , Mitocôndrias/enzimologia
14.
Curr Protoc Chem Biol ; 10(2): e39, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29927113

RESUMO

Antibodies are useful tools for detecting individual proteins in complex samples and for learning about their location, amount, binding partners, and function in cells. Unfortunately, generating antibodies is time consuming and laborious, and their affinity and/or specificity is often limited. This protocol offers a fast and inexpensive alternative to generate antibody surrogates through phage display of a library of fibronectin type III (FN3) monobody variants and affinity selection for binders. © 2018 by John Wiley & Sons, Inc.


Assuntos
Anticorpos Monoclonais/química , Técnicas de Visualização da Superfície Celular , Domínio de Fibronectina Tipo III , Indicadores e Reagentes/síntese química , Anticorpos Monoclonais/imunologia , Especificidade de Anticorpos , Domínio de Fibronectina Tipo III/imunologia , Humanos , Indicadores e Reagentes/química , Biblioteca de Peptídeos
15.
Pest Manag Sci ; 63(6): 555-8, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17437257

RESUMO

Susceptibilities of UK and mainland European samples of Trialeurodes vaporariorum (Westwood) to the neonicotinoid insecticide imidacloprid were investigated over a 7 year period. All 24 strains collected between 1997 and 2003 showed similar baseline levels of susceptibility to that of a known susceptible laboratory strain when exposed to a diagnostic concentration (128 mg L(-1)) of formulated imidacloprid. Two samples collected during 2004, one from the UK and one from The Netherlands, demonstrated reduced susceptibility at this concentration. Using dose-response assays, the presence of resistant individuals was disclosed in both these strains; some individuals were unaffected at doses high enough to induce phytotoxic effects. This report represents the first confirmed cases of neonicotinoid resistance inducing control failures in T. vaporariorum, and highlights a need for careful vigilance to sustain the effectiveness of imidacloprid and related neonicotinoid insecticides.


Assuntos
Hemípteros , Imidazóis , Inseticidas , Nitrocompostos , Animais , Imidazóis/administração & dosagem , Resistência a Inseticidas , Inseticidas/administração & dosagem , Neonicotinoides , Nitrocompostos/administração & dosagem
16.
Pest Manag Sci ; 63(3): 276-81, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17304634

RESUMO

A microencapsulated formulation that gives a burst release of piperonyl butoxide (PBO) several hours before a burst release of a conventional pyrethroid can effectively overcome metabolic resistance in Bemisia tabaci Gennadius, Helicoverpa armigera (Hübner), Aphis gossypii Glover and Myzus persicae Sulzer. This increase in efficacy against resistant pests was reflected in a field trial against B. tabaci on cotton, eliminating the need for two treatments. The ratio between the active insecticide and the synergist was found to be crucial in reducing resistance factors.


Assuntos
Hemípteros/efeitos dos fármacos , Inseticidas/administração & dosagem , Lepidópteros/efeitos dos fármacos , Sinergistas de Praguicidas/administração & dosagem , Butóxido de Piperonila/administração & dosagem , Piretrinas/administração & dosagem , Animais , Preparações de Ação Retardada/toxicidade , Sinergismo Farmacológico , Resistência a Inseticidas , Inseticidas/toxicidade , Sinergistas de Praguicidas/toxicidade , Butóxido de Piperonila/toxicidade , Piretrinas/toxicidade
17.
Pest Manag Sci ; 72(1): 140-9, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25612154

RESUMO

BACKGROUND: We report on the status of imidacloprid and ethiprole resistance in Nilaparvata lugens Stål collected from across South and East Asia over the period 2005-2012. RESULTS: A resistance survey found that field populations had developed up to 220-fold resistance to imidacloprid and 223-fold resistance to ethiprole, and that many of the strains collected showed high levels of resistance to both insecticides. We also found that the cytochrome P450 CYP6ER1 was significantly overexpressed in 12 imidacloprid-resistant populations tested when compared with a laboratory susceptible strain, with fold changes ranging from ten- to 90-fold. In contrast, another cytochrome P450 CYP6AY1, also implicated in imidacloprid resistance, was underexpressed in ten of the populations and only significantly overexpressed (3.5-fold) in a single population from India compared with the same susceptible strain. Further selection of two of the imidacloprid-resistant field strains correlated with an approximate threefold increase in expression of CYP6ER1. CONCLUSIONS: We conclude that overexpression of CYP6ER1 is associated with field-evolved resistance to imidacloprid in brown planthopper populations in five countries in South and East Asia.


Assuntos
Hemípteros/efeitos dos fármacos , Imidazóis/farmacologia , Resistência a Inseticidas , Inseticidas/farmacologia , Nitrocompostos/farmacologia , Pirazóis/farmacologia , Animais , Sudeste Asiático , Sistema Enzimático do Citocromo P-450/metabolismo , Ásia Oriental , Feminino , Hemípteros/genética , Índia , Neonicotinoides
18.
Pest Manag Sci ; 72(3): 618-28, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26374668

RESUMO

BACKGROUND: Under permit from the National Biosafety Commission for the use of genetically modified organisms, releases of a genetically engineered self-limiting strain of Aedes aegypti (OX513A) were used to suppress urban pest Ae. aegypti in West Panama. Experimental goals were to assess the effects on a coexisting population of Ae. albopictus and examine operational parameters with relevance to environmental impact. RESULTS: Ae. albopictus populations were shown to be increasing year upon year at each of three study sites, potentially reflecting a broader-scale incursion into the area. Ae. albopictus abundance was unaffected by a sustained reduction in Ae. aegypti by up to 93% through repeated releases of OX513A. Males accounted for 99.99% of released OX513A, resulting in a sustained mating fraction of 75%. Mean mating competitiveness of OX513A was 0.14. The proportion of OX513A in the local environment decreased by 95% within 25 days of the final release. CONCLUSIONS: There was no evidence for species replacement of Ae. aegypti by Ae. albopictus over the course of this study. No unintentional environmental impacts or elevated operational risks were observed. The potential for this emerging technology to mitigate against disease outbreaks before they become established is discussed.


Assuntos
Aedes , Controle Biológico de Vetores , Aedes/genética , Animais , Animais Geneticamente Modificados/genética , Meio Ambiente , Feminino , Masculino , Panamá
19.
Pest Manag Sci ; 71(7): 957-65, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25078081

RESUMO

BACKGROUND: OX513A is a genetically engineered strain of Aedes aegypti carrying a repressible, dominantly inherited transgene that confers lethality in immature heterozygous progeny. Released male OX513A adults have proven to be effective for the localised suppression of wild Ae. aegypti, highlighting its potential in vector control. Mating and life-table assessments were used to compare OX513A with reared Ae. aegypti strains collected from New Delhi and Aurangabad regions in India. RESULTS: Mating proportions of New Delhi females versus males of OX513A or New Delhi strains were 0.52 and 0.48 respectively, indicating no discrimination by females against either strain, and males of both strains were equally competitive. Developmental time from first instar to adult emergence was significantly longer for OX513A (10.7 ± 0.04 days) than for New Delhi (9.4 ± 0.04 days) and Aurangabad strains (9.1 ± 0.04 days). Differences in mean longevities, female reproductive parameters and population growth parameters between the strains were non-significant. CONCLUSIONS: The laboratory study demonstrates that only minor life-table variations of limited biological relevance exist between OX513A and Indian Ae. aegypti populations, and males had equal potential for mating competitiveness. Thus, results support the OX513A strain as a suitable candidate for continued evaluation towards sustainable management of Ae. aegypti populations in India.


Assuntos
Aedes/genética , Aedes/fisiologia , Animais , Animais Geneticamente Modificados , Feminino , Aptidão Genética , Genótipo , Índia , Longevidade/genética , Masculino , Controle Biológico de Vetores/métodos , Reprodução/genética , Comportamento Sexual Animal
20.
Transplantation ; 78(4): 537-43, 2004 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-15446312

RESUMO

BACKGROUND: A two-part study was initiated to compare kidney transplant patient and transplant professional perceptions regarding immunosuppression-related physical changes and their impact on transplant recipients. METHODS: Parallel surveys were developed and administered to transplant patients and active transplant clinicians. RESULTS: Eighty percent of surveyed patients reported immunosuppression-induced hirsutism, gingival hyperplasia, acne, alopecia, or cushingoid facies. Hirsutism (94%) and gingival hyperplasia (51%) occurred more frequently in cyclosporine patients (p < 0.01); alopecia (30%) occurred more frequently in tacrolimus patients (p < 0.01). Patient reported incidence of physical changes significantly exceeded observations by professionals for every condition (p < 0.01), however 84.4% of affected patients reported feeling "happy to endure" changes "for the sake of having a transplant." Patients also reported emotional and social effects due to physical changes, an outcome underestimated by transplant professionals (p < 0.01). Patients and professionals communicated about physical changes; however, more than half of affected patients believed communication occurred "rarely/never" while over half of the professionals believed communication occurred "every visit/most of the time." Although most physicians believed changes could be addressed, doctors recommended treatment for less than half of the affected patients. When recommended therapy changes were pursued, treatments were effective in the majority of cases. CONCLUSIONS: Incidence of immunosuppression-related physical changes is high and somewhat dependent on drug regimen. Although patients seem willing to accept cosmetic changes for the sake of having a transplant, physical changes have a psychosocial impact that is underestimated by clinicians. Immunosuppression-related physical changes remain underaddressed; effective interventions offer opportunities for improved care.


Assuntos
Alopecia/induzido quimicamente , Hiperplasia Gengival/induzido quimicamente , Hirsutismo/induzido quimicamente , Imunossupressores/efeitos adversos , Transplante de Rim/efeitos adversos , Comunicação , Feminino , Humanos , Masculino , Percepção
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