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1.
BMJ Open Respir Res ; 11(1)2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38719503

RESUMO

INTRODUCTION: Bronchiectasis is a worldwide chronic lung disorder where exacerbations are common. It affects people of all ages, but especially Indigenous populations in high-income nations. Despite being a major contributor to chronic lung disease, there are no licensed therapies for bronchiectasis and there remain relatively few randomised controlled trials (RCTs) conducted in children and adults. Our RCT will address some of these unmet needs by evaluating whether the novel mucoactive agent, erdosteine, has a therapeutic role in children and adults with bronchiectasis.Our primary aim is to determine in children and adults aged 2-49 years with bronchiectasis whether regular erdosteine over a 12-month period reduces acute respiratory exacerbations compared with placebo. Our primary hypothesis is that people with bronchiectasis who regularly use erdosteine will have fewer exacerbations than those receiving placebo.Our secondary aims are to determine the effect of the trial medications on quality of life (QoL) and other clinical outcomes (exacerbation duration, time-to-next exacerbation, hospitalisations, lung function, adverse events). We will also assess the cost-effectiveness of the intervention. METHODS AND ANALYSIS: We are undertaking an international multicentre, double-blind, placebo-RCT to evaluate whether 12 months of erdosteine is beneficial for children and adults with bronchiectasis. We will recruit 194 children and adults with bronchiectasis to a parallel, superiority RCT at eight sites across Australia, Malaysia and Philippines. Our primary endpoint is the rate of exacerbations over 12 months. Our main secondary outcomes are QoL, exacerbation duration, time-to-next exacerbation, hospitalisations and lung function. ETHICS AND DISSEMINATION: The Human Research Ethics Committees (HREC) of Children's Health Queensland (for all Australian sites), University of Malaya Medical Centre (Malaysia) and St. Luke's Medical Centre (Philippines) approved the study. We will publish the results and share the outcomes with the academic and medical community, funding and relevant patient organisations. TRIAL REGISTRATION NUMBER: ACTRN12621000315819.


Assuntos
Bronquiectasia , Expectorantes , Estudos Multicêntricos como Assunto , Qualidade de Vida , Tioglicolatos , Tiofenos , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Bronquiectasia/tratamento farmacológico , Progressão da Doença , Método Duplo-Cego , Expectorantes/uso terapêutico , Ensaios Clínicos Controlados Aleatórios como Assunto , Tioglicolatos/uso terapêutico , Tiofenos/uso terapêutico , Resultado do Tratamento
2.
Neuropsychopharmacology ; 46(10): 1757-1767, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33953341

RESUMO

A major theme of addiction research has focused on the neural substrates of individual differences in the risk for addiction; however, little is known about how vulnerable populations differ from those that are relatively protected. Here, we prospectively measured dopamine (DA) neurotransmission prior to cocaine exposure to predict the onset and course of cocaine use. Using in vivo voltammetry, we first generated baseline profiles of DA release and uptake in the dorsomedial striatum (DMS) and nucleus accumbens of drug-naïve male rats prior to exposing them to cocaine using conditioned place preference (CPP) or operant self-administration. We found that the innate rate of DA uptake in the DMS strongly predicted motivation for cocaine and drug-primed reinstatement, but not CPP, responding when "price" was low, or extinction. We then assessed the impact of baseline variations in DA uptake on cocaine potency in the DMS using ex vivo voltammetry in naïve rats and in rats with DA transporter (DAT) knockdown. DA uptake in the DMS of naïve rats predicted the neurochemical response to cocaine, such that rats with innately faster rates of DA uptake demonstrated higher cocaine potency at the DAT and rats with DAT knockdown displayed reduced potency compared to controls. Together, these data demonstrate that inherent variability in DA uptake in the DMS predicts the behavioral response to cocaine, potentially by altering the apparent potency of cocaine.


Assuntos
Cocaína , Animais , Cocaína/farmacologia , Dopamina , Inibidores da Captação de Dopamina/farmacologia , Individualidade , Masculino , Motivação , Ratos , Ratos Sprague-Dawley
3.
Environ Entomol ; 49(5): 1214-1225, 2020 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-32860049

RESUMO

Beneficial root microbes may mitigate negative effects of crop pests by enhancing plant tolerance or resistance. We used a greenhouse experiment to investigate impacts of commercially available microbial root inoculants on growth and biomass allocation of wheat (Triticum aestivum L. [Cyperales: Poaceae]) and on survival and growth of the gall-inducing wheat pest Hessian fly, Mayetiola destructor (Say). A factorial design was used, with two near-isogenic wheat lines (one susceptible to Hessian fly, the other resistant), two levels of insect infestation (present, absent), and four inoculants containing: 1) Azospirillum brasilense  Tarrand et al. (Rhodospirillales: Azospirillaceae), a plant growth-promoting bacterium, 2) Rhizophagus intraradices (N.C. Schenck & G.S. Sm.) (Glomerales: Glomeraceae), an arbuscular mycorrhizal fungus, 3) A. brasilense + R. intraradices, and 4) control, no inoculant. Larval feeding stunted susceptible wheat shoots and roots. Plants had heavier roots and allocated a greater proportion of biomass to roots when plants received the inoculant with R. intraradices, regardless of wheat genotype or insect infestation. Plants receiving the inoculant containing A. brasilense (alone or with R. intraradices) had comparable numbers of tillers between infested and noninsect-infested plants and, if plants were susceptible, a greater proportion of aboveground biomass was allocated to tillers. However, inoculants did not impact density or performance of Hessian fly immatures or metrics associated with adult fitness. Larvae survived and grew normally on susceptible plants and mortality was 100% on resistant plants irrespective of inoculants. This initial study suggests that by influencing plant biomass allocation, microbial inoculants may offset negative impacts of Hessian flies, with inoculant identity impacting whether tolerance is related to root or tiller growth.


Assuntos
Inoculantes Agrícolas , Dípteros , Animais , Biomassa , Fungos , Triticum
4.
New Phytol ; 225(5): 1852-1872, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31774564

RESUMO

At the colonization site of a foreign entity, plant cells alter their trajectory of growth and development. The resulting structure - a plant gall - accommodates various needs of the foreigner, which are phylogenetically diverse: viruses, bacteria, protozoa, oomycetes, true fungi, parasitic plants, and many types of animals, including rotifers, nematodes, insects, and mites. The plant species that make galls also are diverse. We assume gall production costs the plant. All is well if the foreigner provides a gift that makes up for the cost. Nitrogen-fixing nodule-inducing bacteria provide nutritional services. Gall wasps pollinate fig trees. Unfortunately for plants, most galls are made for foes, some of which are deeply studied pathogens and pests: Agrobacterium tumefaciens, Rhodococcus fascians, Xanthomonas citri, Pseudomonas savastanoi, Pantoea agglomerans, 'Candidatus' phytoplasma, rust fungi, Ustilago smuts, root knot and cyst nematodes, and gall midges. Galls are an understudied phenomenon in plant developmental biology. We propose gall inception for discovering unifying features of the galls that plants make for friends and foes, talk about molecules that plants and gall-inducers use to get what they want from each other, raise the question of whether plants colonized by arbuscular mycorrhizal fungi respond in a gall-like manner, and present a research agenda.


Assuntos
Emigrantes e Imigrantes , Interações Hospedeiro-Parasita , Animais , Humanos , Tumores de Planta , Pseudomonas , Rhodococcus , Xanthomonas
5.
F1000Res ; 8: 154, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31656585

RESUMO

Cumulative grade point average (CGPA) is a system for calculation of GPA scores and is one way to determine a student's academic performance in a university setting. In Nigeria, an employer evaluates a student's academic performance using their CGPA score. For this study, data were collected from a student database of a private school in the south-west geopolitical zone in Nigeria. Regression analysis, correlation analysis, and analysis of variance (F-test) were employed to determine the study year that students perform better based on CGPA. According to the results, it was observed that students perform much better in year three (300 Level) and year four (400 Level) compared to other levels. In conclusion, we strongly recommend the private university to introduce program that will improve the academic performance of students from year one (100 level).


Assuntos
Critérios de Admissão Escolar , Universidades , Humanos , Nigéria , Análise de Regressão
6.
J Econ Entomol ; 112(5): 2398-2406, 2019 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-31102452

RESUMO

The agricultural landscape of North Dakota is changing. Corn and soybean are now commonplace, but once were rare. Spring sown wheat Triticum aestivum L. and durum wheat Triticum turgidum spp. durum continue to be dominant, but more winter-sown wheat is expected in the future. The presence of wheat in the landscape throughout much of the year will benefit populations of the Hessian fly, Mayetiola destructor (Say), which occurs throughout the state, sometimes in large numbers. Hessian fly is unusual among crop pests for which resources for plant resistance are well developed. On wheat genotypes expressing a single effective H resistance gene, 100% of larvae die before exhibiting any growth. Over 35 H genes in the public domain are available for crossing into elite cultivars. We explored the effectiveness of 31 Hessian fly resistance genes for a North Dakota Hessian fly population. Six genes-H4, H15, H21, H23, H26, and H29-caused 100% larval mortality. Seven others caused at least 80% mortality. Experimental data were used to address three additional questions. Do adult females avoid laying eggs on plants that will kill their offspring: Are neonate larvae able to detect resistance that will end up killing them? Do all 31 genes confer equal protection against larval-induced growth deficits? North Dakota wheat breeders have the necessary tools to create highly resistant wheat cultivars. So far, H genes have been deployed singly in cultivars. Advances in plant breeding will enable gene stacking, a more durable strategy over time.


Assuntos
Dípteros , Triticum , Animais , Feminino , Genótipo , Larva , North Dakota
7.
Pediatr Radiol ; 47(10): 1237-1248, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29052771

RESUMO

There is a lack of standardized approach and terminology to classify the diverse spectrum of manifestations in tuberculosis. It is important to recognize the different clinical and radiographic patterns to guide treatment. As a result of changing epidemiology, there is considerable overlap in the radiologic presentations of primary tuberculosis and post-primary tuberculosis. In this article we promote a standardized approach in clinical and radiographic classification for children suspected of having or diagnosed with childhood tuberculosis. We propose standardized terms to diminish confusion and miscommunication, which can affect management. In addition, we present pitfalls and limitations of imaging.


Assuntos
Radiografia Torácica/normas , Doenças Torácicas/classificação , Doenças Torácicas/diagnóstico por imagem , Tuberculose/classificação , Tuberculose/diagnóstico por imagem , Criança , Diagnóstico Diferencial , Progressão da Doença , Humanos , Terminologia como Assunto , Tuberculose dos Linfonodos/classificação , Tuberculose dos Linfonodos/diagnóstico por imagem , Tuberculose Pulmonar/diagnóstico por imagem
8.
J Insect Physiol ; 84: 1, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26809875
10.
Am J Transplant ; 16(5): 1474-9, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26587971

RESUMO

There is no approved therapy for hepatitis C virus (HCV) infection after kidney transplantation, and no data regarding the use of new-generation direct antiviral agents (DAAs) have been published so far. The aims of this pilot study were to assess the efficacy and safety of an interferon-free sofosbuvir-based regimen to treat chronic HCV infection in kidney transplant recipients. Twenty-five kidney transplant recipients with chronic HCV infection were given, for 12 (n = 19) or 24 weeks (n = 6), sofosbuvir plus ribavirin (n = 3); sofosbuvir plus daclatasvir (n = 4); sofosbuvir plus simeprevir, with (n = 1) or without ribavirin (n = 6); sofosbuvir plus ledipasvir, with (n = 1) or without ribavirin (n = 9); and sofosbuvir plus pegylated-interferon plus ribavirin (n = 1). A rapid virological response, defined by undetectable viremia at week 4 after starting DAA therapy, was observed in 22 of the 25 patients (88%). At the end of therapy, HCV RNA was undetectable in all patients. At 4 and 12 weeks after completing DAA therapy, all had a sustained virological response. The tolerance to anti-HCV therapy was excellent and no adverse event was observed. A significant decrease in calcineurin inhibitor levels was observed after HCV clearance. New-generation oral DAAs are efficient and safe to treat HCV infection after kidney transplantation.


Assuntos
Antivirais/uso terapêutico , Sobrevivência de Enxerto/efeitos dos fármacos , Hepacivirus/efeitos dos fármacos , Hepatite C/tratamento farmacológico , Falência Renal Crônica/complicações , Transplante de Rim/efeitos adversos , Sofosbuvir/uso terapêutico , DNA Viral/genética , Feminino , Seguimentos , Taxa de Filtração Glomerular , Hepacivirus/genética , Hepatite C/virologia , Humanos , Falência Renal Crônica/cirurgia , Testes de Função Renal , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Prognóstico , Fatores de Risco , Segurança , Carga Viral
11.
J Insect Physiol ; 84: 4-21, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26705897

RESUMO

Insects that reprogram host plants during colonization remind us that the insect side of plant-insect story is just as interesting as the plant side. Insect effectors secreted by the salivary glands play an important role in plant reprogramming. Recent discoveries point to large numbers of salivary effectors being produced by a single herbivore species. Since genetic and functional characterization of effectors is an arduous task, narrowing the field of candidates is useful. We present ideas about types and functions of effectors from research on blood-feeding parasites and their mammalian hosts. Because of their importance for human health, blood-feeding parasites have more tools from genomics and other - omics than plant-feeding parasites. Four themes have emerged: (1) mechanical damage resulting from attack by blood-feeding parasites triggers "early danger signals" in mammalian hosts, which are mediated by eATP, calcium, and hydrogen peroxide, (2) mammalian hosts need to modulate their immune responses to the three "early danger signals" and use apyrases, calreticulins, and peroxiredoxins, respectively, to achieve this, (3) blood-feeding parasites, like their mammalian hosts, rely on some of the same "early danger signals" and modulate their immune responses using the same proteins, and (4) blood-feeding parasites deploy apyrases, calreticulins, and peroxiredoxins in their saliva to manipulate the "danger signals" of their mammalian hosts. We review emerging evidence that plant-feeding insects also interfere with "early danger signals" of their hosts by deploying apyrases, calreticulins and peroxiredoxins in saliva. Given emerging links between these molecules, and plant growth and defense, we propose that these effectors interfere with phytohormone signaling, and therefore have a special importance for gall-inducing and leaf-mining insects, which manipulate host-plants to create better food and shelter.


Assuntos
Comportamento Alimentar , Insetos/fisiologia , Plantas/parasitologia , Animais , Apirase/metabolismo , Sangue , Calreticulina/metabolismo , Interações Hospedeiro-Parasita , Humanos , Peroxirredoxinas/metabolismo , Doenças das Plantas/parasitologia , Reguladores de Crescimento de Plantas/metabolismo , Imunidade Vegetal , Plantas/imunologia , Transdução de Sinais
12.
Environ Entomol ; 44(3): 601-9, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26313966

RESUMO

Gall-inducing insects are known for altering source-sink relationships within plants. Changes in photosynthesis may contribute to this phenomenon. We investigated photosynthetic responses in wheat [Triticum aestivum L. (Poaceae: Triticeae)] seedlings attacked by the Hessian fly [Mayetiola destructor (Say) (Diptera: Cecidomyiidae], which uses a salivary effector-based strategy to induce a gall nutritive tissue in susceptible plants. Resistant plants have surveillance systems mediated by products of Resistance (R) genes. Detection of a specific salivary effector triggers downstream responses that result in a resistance that kills neonate larvae. A 2 × 2 factorial design was used to study maximum leaf photosynthetic assimilation and stomatal conductance rates. The plant treatments were-resistant or susceptible wheat lines expressing or not expressing the H13 resistance gene. The insect treatments were-no attack (control) or attack by larvae killed by H13 gene-mediated resistance. Photosynthesis was measured for the second and third leaves of the seedling, the latter being the only leaf directly attacked by larvae. We predicted effector-based attack would trigger increases in photosynthetic rates in susceptible but not resistant plants. For susceptible plants, attack was associated with increases (relative to controls) in photosynthesis for the third but not the second leaf. For resistant plants, attack was associated with increases in photosynthesis for both the second and third leaves. Mechanisms underlying the increases appeared to differ. Resistant plants exhibited responses suggesting altered source-sink relationships. Susceptible plants exhibited responses suggesting a mechanism other than altered source-sink relationships, possibly changes in water relations that contributed to increased stomatal conductance.


Assuntos
Dípteros/crescimento & desenvolvimento , Interações Hospedeiro-Parasita , Fotossíntese/fisiologia , Triticum/parasitologia , Animais , Genes de Plantas , Larva/crescimento & desenvolvimento , Folhas de Planta/genética , Folhas de Planta/imunologia , Folhas de Planta/metabolismo , Folhas de Planta/parasitologia , Triticum/genética , Triticum/imunologia , Triticum/metabolismo
13.
PLoS One ; 9(6): e100958, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24964065

RESUMO

Highly specialized obligate plant-parasites exist within several groups of arthropods (insects and mites). Many of these are important pests, but the molecular basis of their parasitism and its evolution are poorly understood. One hypothesis is that plant parasitic arthropods use effector proteins to defeat basal plant immunity and modulate plant growth. Because avirulence (Avr) gene discovery is a reliable method of effector identification, we tested this hypothesis using high-resolution molecular genetic mapping of an Avr gene (vH13) in the Hessian fly (HF, Mayetiola destructor), an important gall midge pest of wheat (Triticum spp.). Chromosome walking resolved the position of vH13, and revealed alleles that determine whether HF larvae are virulent (survive) or avirulent (die) on wheat seedlings carrying the wheat H13 resistance gene. Association mapping found three independent insertions in vH13 that appear to be responsible for H13-virulence in field populations. We observed vH13 transcription in H13-avirulent larvae and the salivary glands of H13-avirulent larvae, but not in H13-virulent larvae. RNA-interference-knockdown of vH13 transcripts allowed some H13-avirulent larvae to escape H13-directed resistance. vH13 is the first Avr gene identified in an arthropod. It encodes a small modular protein with no sequence similarities to other proteins in GenBank. These data clearly support the hypothesis that an effector-based strategy has evolved in multiple lineages of plant parasites, including arthropods.


Assuntos
Dípteros/genética , Genes de Insetos/genética , Genes de Plantas , Marcadores Genéticos , Virulência/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Mapeamento Cromossômico , Dípteros/crescimento & desenvolvimento , Dípteros/patogenicidade , Teste de Complementação Genética , Dados de Sequência Molecular , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Triticum/genética , Triticum/parasitologia
14.
BMC Genomics ; 15: 501, 2014 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-24948464

RESUMO

BACKGROUND: The chemical senses of insects mediate behaviors that are closely linked to survival and reproduction. The order Diptera contains two model organisms, the vinegar fly Drosophila melanogaster and the mosquito Anopheles gambiae, whose chemosensory genes have been extensively studied. Representing a third dipteran lineage with an interesting phylogenetic position, and being ecologically distinct by feeding on plants, the Hessian fly (Mayetiola destructor Say, Diptera: Cecidomyiidae) genome sequence has recently become available. Among plant-feeding insects, the Hessian fly is unusual in 'reprogramming' the plant to create a superior food and in being the target of plant resistance genes, a feature shared by plant pathogens. Chemoreception is essential for reproductive success, including detection of sex pheromone and plant-produced chemicals by males and females, respectively. RESULTS: We identified genes encoding 122 odorant receptors (OR), 28 gustatory receptors (GR), 39 ionotropic receptors (IR), 32 odorant binding proteins, and 7 sensory neuron membrane proteins in the Hessian fly genome. We then mapped Illumina-sequenced transcriptome reads to the genome to explore gene expression in male and female antennae and terminal abdominal segments. Our results reveal that a large number of chemosensory genes have up-regulated expression in the antennae, and the expression is in many cases sex-specific. Sex-specific expression is particularly evident among the Or genes, consistent with the sex-divergent olfactory-mediated behaviors of the adults. In addition, the large number of Ors in the genome but the reduced set of Grs and divergent Irs suggest that the short-lived adults rely more on long-range olfaction than on short-range gustation. We also report up-regulated expression of some genes from all chemosensory gene families in the terminal segments of the abdomen, which play important roles in reproduction. CONCLUSIONS: We show that a large number of the chemosensory genes in the Hessian fly genome have sex- and tissue-specific expression profiles. Our findings provide the first insights into the molecular basis of chemoreception in plant-feeding flies, representing an important advance toward a more complete understanding of olfaction in Diptera and its links to ecological specialization.


Assuntos
Dípteros/genética , Dípteros/metabolismo , Perfilação da Expressão Gênica , Herbivoria/genética , Animais , Mapeamento Cromossômico , Feminino , Ontologia Genética , Masculino , Proteínas de Membrana/genética , Anotação de Sequência Molecular , Especificidade de Órgãos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores Odorantes/genética , Células Receptoras Sensoriais/metabolismo
15.
J Morphol ; 274(11): i-iii, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24132950

RESUMO

Cover illustration. Mayetiola destructor is a major pest of wheat in Europe, North Africa and North America. In this issue of the Journal of Morphology, Schneeberg et al. (pp. 1299-1311) investigate the adult head structures of the cecidomyiid fly and compared their findings with evolutionarily less successful families within Bibionomorpha. The cover image shows a histological cross section of the head of Mayetiola destructor (Diptera, Cecidomyiidae).


Assuntos
Dípteros/anatomia & histologia , Animais , Cabeça/anatomia & histologia
16.
J Morphol ; 274(11): 1299-311, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24026972

RESUMO

The adult head of the Hessian fly Mayetiola destructor was examined and described in detail. Morphological features are evaluated with respect to phylogenetic implications and possible effects of miniaturisation. Preserved groundplan features of Diptera are the orthognathous orientation of the head, the vestiture of small microtrichia (possible autapomorphy), filiform antennae inserted frontally between the compound eyes, the presence of a clypeolabral muscle (possible autapomorphy), the presence of labellae (autapomorphy), and the presence of only one premental retractor. Potential synapomorphies of the groups assigned to Bibionomorpha are the origin of M. tentorioscapalis medialis on the frons and the loss of M. craniolacinialis. Further apomorphies of Cecidomyiidae identified in Mayetiola are the unusually massive anterior tentorial arm, the absence of the labro-epipharyngeal food channel, the absence of the lacinia, and the presence of antennal sensilla connected by a seta, a feature not known from any other group of Diptera. The very large size of the compound eyes (in relation to the entire head surface) and the complete loss of ocelli are possible effects of miniaturization. The large size of the brain (in relation to the cephalic lumen), the unusual shape of the optic lobes, and the absence of the frontal ganglion as a separate structure are probably also linked with size reduction.


Assuntos
Dípteros/anatomia & histologia , Animais , Antenas de Artrópodes/anatomia & histologia , Encéfalo/anatomia & histologia , Dípteros/classificação , Feminino , Cabeça/anatomia & histologia , Masculino , Músculos/anatomia & histologia , Filogenia , Sensilas/anatomia & histologia
17.
Environ Entomol ; 42(1): 123-30, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23339793

RESUMO

For animals that lay eggs, a longstanding question is, why do females choose particular oviposition sites? For insects that lay eggs on plants there are three hypotheses: maximizing suitable habitat for juveniles, maximizing female lifespan, and maximizing egg survival. We investigated the function of the oviposition-site choice behavior of a gall midge, the Hessian fly, Mayetiola destructor (Say). In spite of living less than a day and having hundreds of eggs, the ovipositing female is choosy about the placement of eggs. Choosiness makes sense. The tiny gall-making neonate larva has limited movement and strict requirements for colonization. We examined whether offspring benefit from the Hessian fly female's preference for the plant's youngest leaf. To do this we restricted the female's access to the first, second, or third leaf of a seedling (wheat Triticum aestivum L.) plant. Being placed on older leaves did not impact egg survival or larval survival during migration to attack sites at the base of the plant, but did have negative impacts on egg-to-adult survival (reduced by 48%) and reproductive potential (reduced by 30-45%). These negative impacts appear to come from larvae having to search harder to find the limited number of reactive plant cells that can be reprogrammed to form the gall nutritive tissue. We propose that the ability of larvae to find these reactive cells in spite of being placed on an older leaf is important because it creates leeway for female behavior to evolve in the face of other selection pressures, e.g., attack by egg parasitoids.


Assuntos
Dípteros/fisiologia , Interações Hospedeiro-Parasita , Oviposição , Triticum/parasitologia , Animais , Feminino , Larva/crescimento & desenvolvimento , Masculino , Folhas de Planta/parasitologia , Plântula/parasitologia
19.
Annu Rev Phytopathol ; 50: 339-57, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22656645

RESUMO

Gall midges constitute an important group of plant-parasitic insects. The Hessian fly (HF; Mayetiola destructor), the most investigated gall midge, was the first insect hypothesized to have a gene-for-gene interaction with its host plant, wheat (Triticum spp.). Recent investigations support that hypothesis. The minute larval mandibles appear to act in a manner that is analogous to nematode stylets and the haustoria of filamentous plant pathogens. Putative effector proteins are encoded by hundreds of genes and expressed in the HF larval salivary gland. Cultivar-specific resistance (R) genes mediate a highly localized plant reaction that prevents the survival of avirulent HF larvae. Fine-scale mapping of HF avirulence (Avr) genes provides further evidence of effector-triggered immunity (ETI) against HF in wheat. Taken together, these discoveries suggest that the HF, and other gall midges, may be considered biotrophic, or hemibiotrophic, plant pathogens, and they demonstrate the potential that the wheat-HF interaction has in the study of insect-induced plant gall formation.


Assuntos
Dípteros/patogenicidade , Interações Hospedeiro-Parasita , Doenças das Plantas/parasitologia , Triticum/parasitologia , Animais , Dípteros/genética , Dípteros/crescimento & desenvolvimento , Feminino , Larva , Modelos Biológicos , Doenças das Plantas/imunologia , Imunidade Vegetal , Triticum/genética , Triticum/imunologia , Virulência
20.
J Econ Entomol ; 104(4): 1393-405, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21882709

RESUMO

Resistance (R) genes have a proven record for protecting plants against biotic stress. A problem is parasite adaptation via Avirulence (Avr) mutations, which allows the parasite to colonize the R gene plant. Scientists hope to make R genes more durable by stacking them in a single cultivar. However, stacking assumes that R gene-mediated resistance has no fitness cost for the plant. We tested this assumption for wheat's resistance to Hessian fly, Mayetiola destructor (Say) (Diptera: Cecidomyiidae). Our study included ten plant fitness measures and four wheat genotypes, one susceptible, and three expressing either the H6, H9, or H13 resistance gene. Because R gene-mediated resistance has two components, we measured two types of costs: the cost of the constitutively-expressed H gene, which functions in plant surveillance, and the cost of the downstream induced responses, which were triggered by Hessian fly larvae rather than a chemical elicitor. For the constitutively expressed Hgene, some measures indicated costs, but a greater number of measures indicated benefits of simply expressing the H gene. For the induced resistance, instead of costs, resistant plants showed benefits of being attacked. Resistant plants were more likely to survive attack than susceptible plants, and surviving resistant plants produced higher yield and quality. We discuss why resistance to the Hessian fly has little or no cost and propose that tolerance is important, with compensatory growth occurring after H gene-mediated resistance kills the larva. We end with a caution: Given that plants were given good growing conditions, fitness costs may be found under conditions of greater biotic or abiotic stress.


Assuntos
Dípteros/fisiologia , Aptidão Genética , Interações Hospedeiro-Parasita/genética , Triticum/genética , Triticum/parasitologia , Animais , Genes de Plantas , Genótipo , Larva
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