RESUMO
Alzheimer's disease (AD) is characterized by progressive, irreversible loss of memory and cognitive function. Drosophila melanogaster and other animal models are used to study several diseases, in order to elucidate unknown mechanisms and develop potential therapies. Molecular studies require biological samples and, for neuropathologies such as AD biopsy of the human brain, are invasive and potentially damaging. The solution is to use animal models, such as D. melanogaster, which is a model organism that can replace mammalian organisms in such studies. In this study, we evaluated the climbing ability and differential gene expression during AD progression due to the amylodoigenic pathway using RNA-seq, and we performed an in silico analysis of a fruit fly AD-like GFP (Green Fluorescent Protein) model with GFP expression in the pan-neural elav driver. A total of 1388 genes were differentially expressed in all analyzed groups. The main pathways related to those Differentially Expressed Genes (DEGs) during aging and AD progression were evaluated using the fly genes and human orthologs, in order to link genomic information to higher-order functional information with gene pathway mapping. We identified pathways present in all analyzed groups, such as metabolic pathways, ribosomal pathways, proteasome pathways and immune system pathways. Some of the genes were validated by qPCR. Knockdown of CG17754 gene by RNAi promoted degeneration in the fly eye, validating these findings in vivo. The identification of similarities in molecular pathways between the transgenic fly AD-like GFP model and mammals related to AD provides new insights into the use of this fly in screening novel anti-AD drugs.
Assuntos
Doença de Alzheimer , Drosophila melanogaster , Doença de Alzheimer/metabolismo , Animais , Encéfalo/metabolismo , Modelos Animais de Doenças , Drosophila melanogaster/genética , Expressão Gênica , Mamíferos , RNA-SeqRESUMO
In bees from genus Melipona, differential feeding is not enough to fully explain female polyphenism. In these bees, there is a hypothesis that in addition to the environmental component (food), a genetic component is also involved in caste differentiation. This mechanism has not yet been fully elucidated and may involve epigenetic and metabolic regulation. Here, we verified that the genes encoding histone deacetylases HDAC1 and HDAC4 and histone acetyltransferase KAT2A were expressed at all stages of Melipona scutellaris, with fluctuations between developmental stages and castes. In larvae, the HDAC genes showed the same profile of Juvenile Hormone titers-previous reported-whereas the HAT gene exhibited the opposite profile. We also investigated the larvae and larval food metabolomes, but we did not identify the putative queen-fate inducing compounds, geraniol and 10-hydroxy-2E-decenoic acid (10HDA). Finally, we demonstrated that the histone deacetylase inhibitor 10HDA-the major lipid component of royal jelly and hence a putative regulator of honeybee caste differentiation-was unable to promote differentiation in queens in Melipona scutellaris. Our results suggest that epigenetic and hormonal regulations may act synergistically to drive caste differentiation in Melipona and that 10HDA is not a caste-differentiation factor in Melipona scutellaris.
Assuntos
Abelhas/fisiologia , Comportamento Alimentar/fisiologia , Regulação da Expressão Gênica no Desenvolvimento , Hierarquia Social , Monoterpenos Acíclicos/metabolismo , Animais , Epigênese Genética , Ácidos Graxos/metabolismo , Ácidos Graxos Monoinsaturados/metabolismo , Feminino , Histona Acetiltransferases/genética , Histona Acetiltransferases/metabolismo , Histona Desacetilases/genética , Histona Desacetilases/metabolismo , Proteínas de Insetos/antagonistas & inibidores , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Hormônios Juvenis/metabolismoRESUMO
Vitamin D3 (VD3) deficiency increases DNA damage, while supplementation may exert a pro-oxidant activity, prevent viral infections and formation of tumors. The aim of this study was to investigate the mutagenicity and carcinogenicity of VD3 alone or in combination with doxorubicin (DXR) using the Somatic Mutation and Recombination Test and the Epithelial Tumor Test, both in Drosophila melanogaster. For better understanding of the molecular interactions of VD3 and receptors, in silico analysis were performed with molecular docking associated with molecular dynamics. Findings revealed that VD3 alone did not increase the frequency of mutant spots, but reduced the frequency of mutant spots when co-administered with DXR. In addition, VD3 did not alter the recombinogenic effect of DXR in both ST and HB crosses. VD3 alone did not increase the total frequency of tumor, but significantly reduced the total frequency of tumor when co-administered with DXR. Molecular modeling and molecular dynamics between calcitriol and Ecdysone Receptor (EcR) showed a stable interaction, indicating the possibility of signal transduction between VD3 and EcR. In conclusion, under these experimental conditions, VD3 has modulatory effects on the mutagenicity and carcinogenicity induced by DXR in somatic cells of D. melanogaster and exhibited satisfactory interactions with the EcR.
Assuntos
Carcinogênese/efeitos dos fármacos , Colecalciferol/farmacologia , Doxorrubicina/toxicidade , Drosophila melanogaster/efeitos dos fármacos , Animais , Antibióticos Antineoplásicos/toxicidade , Hormônios e Agentes Reguladores de Cálcio/farmacologia , Drosophila melanogaster/genética , Feminino , Masculino , Modelos Moleculares , Simulação de Dinâmica Molecular , Estrutura Molecular , Mutação/efeitos dos fármacos , Conformação Proteica , Receptores de Calcitriol/química , Receptores de Calcitriol/metabolismo , Recombinação GenéticaRESUMO
Antiparasitic substances are chemicals used to control or kill endoparasites and ectoparasites. Based on the premise that Ivermectin (IVM) and Amoxicillin (AMX) are commonly considered in parasitic control in mammals, the present study aimed to evaluate the carcinogenic and genotoxic potential of different concentrations of IVM and AMX through the detection of epithelial tumor test in Drosophila melanogaster. Third-instar larvae descending from the cross between wts/TM3, Sb1 females and mwh/mwh males were treated with different concentrations of IVM (2.9, 5.8, 11.6 and 23.2 x 10-17 mM) or AMX (1.37, 2.74, 5.48 and 10.9 x 10-16mM). The results revealed that IVM increased the frequency of epithelial tumor in D. melanogaster considering all evaluated concentrations, while AMX showed no carcinogenic effect. Furthermore, the Micronucleus (MN) test in Tradescantia pallida was used to evaluate the genotoxic effect of IVM and AMX. T. pallida individuals were exposed for 8 hours at different concentrations of IVM (5.71, 11.42, 22.84 and 45.68 x 10-5mM) or AMX (5.13, 10.26, 20.52 and 41.05 x 10-3mM). Findings showed an increase in the frequency of micronuclei in T. pallida treated with 11.42, 22.84 and 45.68 x 10-5mM of IVM. We conclude that chronic exposure to IVM is directly associated with events resulting from genetic instability (genotoxicity and carcinogenicity). On the other hand, AMX was neither carcinogenic nor genotoxic for D. melanogaster and T. pallida.
Assuntos
Amoxicilina/toxicidade , Antiparasitários/toxicidade , Carcinógenos/toxicidade , Ivermectina/toxicidade , Mutagênicos/toxicidade , Animais , Carcinoma/induzido quimicamente , Dano ao DNA , Drosophila melanogaster/efeitos dos fármacos , Drosophila melanogaster/genética , Feminino , Larva/efeitos dos fármacos , Larva/genética , Masculino , Testes de Mutagenicidade , Tradescantia/efeitos dos fármacos , Tradescantia/genéticaRESUMO
Physico-chemical and toxicological analyses are of fundamental importance to determine water quality. The objectives of the present study were to evaluate the toxicity, mutagenicity and carcinogenicity of samples from the Mumbuca Stream and the Perdizes River, through both SMART and the wts test, respectively, in somatic cells of Drosophila melanogaster and to quantify the amount of heavy metals and other pollutants, which are indicative of environmental quality. Water samples were collected (M1, M2, P1, P2 and MP) and submitted to physico-chemical analysis, calculating the water quality index for each sampling site. In order to evaluate the toxicity, mutagenicity and carcinogenicity of the samples, third instar larvae descended from the crossing between virgin female wts/TM3, sb1 and mwh/mwh males (wts test) and ST and HB (SMART) crosses were treated with samples from P1, P2, M1, M2 and MP sites. The physico-chemical analysis and the biological assay allowed us to conclude that undetected values for heavy metals and the low frequency of mutant spots (SMART) and epithelial tumor (wts) in treated flies from the Mumbuca Stream and Perdizes River may be due to the reduction of ceramic activities in the municipality. The physico-chemical analyzes identified altered the environmental quality parameters, which directly influenced the survival of D. melanogaster treated with samples of M2 and MP, which according to the WQI were classified as regular and poor environmental quality, respectively. The altered parameters may be due to clandestine domestic sewage sent downstream of the effluent.
Assuntos
Monitoramento Ambiental/métodos , Mutagênicos/toxicidade , Rios/química , Esgotos/análise , Qualidade da Água , Animais , Drosophila melanogaster/citologia , Drosophila melanogaster/efeitos dos fármacos , Feminino , Larva/efeitos dos fármacos , Masculino , Metais Pesados/análiseRESUMO
Thiamethoxam (TMX) belongs to a class of neuro-active insecticides referred as neonicotinoids, while actara® (AC) is one of the most popular TMX-based products in Brazil. The aim of this study was to evaluate the mutagenic, recombinogenic and carcinogenic potential of TMX and AC insecticides. The mutagenic and recombinogenic effect of TMX and AC were evaluated in vivo by the Somatic Mutation and Recombination Test (SMART) while carcinogenic effects were evaluated through the Test for Detection of Epithelial Tumor Clones (wts test), both in somatic cells of Drosophila melanogaster. In the SMART, third instar larvae from standard (ST) and high bioactivation (HB) crosses were treated with different concentrations of TMX and AC (2.4; 4.8; 9.7 × 10-4 mM and 1.9 × 10-3 mM). The results revealed mutagenic effects at the highest concentrations tested in the HB cross. In the test for the detection of epithelial tumor, third instar larvae resulting from the cross between wts/TM3, Sb1 virgin females and mwh/mwh males were treated with the same concentrations of TMX and AC used in the SMART. No carcinogenic effect was observed at any of the concentrations tested. In this work, the inhibition of the mechanism of repair by homologous recombination was observed in flies exposed to 9.7 × 10-4 and 1.9 × 10-3 mM of AC. In conclusion, TMX and AC demonstrated to be a promutagen in the highest concentrations tested.
Assuntos
Drosophila melanogaster/efeitos dos fármacos , Neonicotinoides/farmacologia , Nitrocompostos/farmacologia , Oxazinas/farmacologia , Tiazóis/farmacologia , Animais , Brasil , Carcinogênese/efeitos dos fármacos , Drosophila melanogaster/citologia , Feminino , Inseticidas/farmacologia , Masculino , Mutagênese/efeitos dos fármacos , Testes de Mutagenicidade/métodos , Recombinação Genética/efeitos dos fármacos , TiametoxamRESUMO
Abstract Stingless bees of the genus Melipona, have long been considered an enigmatic case among social insects for their mode of caste determination, where in addition to larval food type and quantity, the genotype also has a saying, as proposed over 50 years ago by Warwick E. Kerr. Several attempts have since tried to test his Mendelian two-loci/two-alleles segregation hypothesis, but only recently a single gene crucial for sex determination in bees was evidenced to be sex-specifically spliced and also caste-specifically expressed in a Melipona species. Since alternative splicing is frequently associated with epigenetic marks, and the epigenetic status plays a major role in setting the caste phenotype in the honey bee, we investigated here epigenetic chromatin modification in the stingless bee Melipona scutellaris. We used an ELISA-based methodology to quantify global methylation status and western blot assays to reveal histone modifications. The results evidenced DNA methylation/demethylation events in larvae and pupae, and significant differences in histone methylation and phosphorylation between newly emerged adult queens and workers. The epigenetic dynamics seen in this stingless bee species represent a new facet in the caste determination process in Melipona bees and suggest a possible mechanism that is likely to link a genotype component to the larval diet and adult social behavior of these bees.
RESUMO
Fipronil (FP) is an insecticide that belongs to the phenylpyrazole chemical family and is used to control pests by blocking GABA receptor at the entrance channel of the chlorine neurons. The aim of this study was to evaluate the mutagenic, recombinogenic and carcinogenic potential of FP. The mutagenic and recombinogenic effects were evaluated using the somatic mutation and recombination test (SMART) on wing cells of Drosophila melanogaster. Third instar larvae from standard (ST) and high bioactivation (HB) crosses were treated with different concentrations of FP (0.3, 0.7, 1.5 or 3.0 × 10-5 mM). The results showed mutagenic effects at all concentrations tested in the HB cross; and all concentrations tested in the ST cross, except at concentration of 0.7 × 10-5 mM. The carcinogenic effect of FP was assayed through the test for detection of epithelial tumor (warts) in D. melanogaster. Third instar larvae from wts/TM3 virgin females mated to mwh/mwh males were treated with different concentrations of FP (0.3, 0.7, 1.5 or 3.0 × 10-5 mM). All these concentrations induced a statistically significant increase in tumor frequency. In conclusion, FP proved to be mutagenic, recombinogenic and carcinogenic in somatic cells of D. melanogaster.
Assuntos
Carcinógenos/toxicidade , Drosophila melanogaster/efeitos dos fármacos , Inseticidas/toxicidade , Testes de Mutagenicidade/métodos , Neoplasias/induzido quimicamente , Pirazóis/toxicidade , Asas de Animais/patologia , Animais , Feminino , Larva/efeitos dos fármacos , Masculino , Mutagênese , Mutagênicos/toxicidade , Recombinação Genética/efeitos dos fármacos , Asas de Animais/efeitos dos fármacosRESUMO
Soft drinks are industrialized unfermented beverages, free of alcohol, carbonated, rich in artificial flavors and sugar. The intense consumption of such beverages can be related to not inheritable diseases such as caries, allergy, cellulite and stretch marks, gastrointestinal disorders, diabetes and cancer. The aim of this study was to evaluate the carcinogenic potential of different concentrations of soft drinks produced in the Uberlândia city, Minas Gerais State, Brazil, by means of Epithelial Tumor Detection Test using Drosophila melanogaster as a model. Third stage larvae descendants of crosses between D. melanogaster virgin females wts/TM3, sb¹ and males mwh/mwh were treated with different concentrations (0.83, 1.66 or 3.33 mL/g) of cola, diet cola, orange or lemon soft drinks. The total epithelial tumor rate observed in flies treated with 3.33 mL/g of cola and orange soft drinks was higher than the negative control. The diet cola and lemon caused no significant increase in the overall frequency of epithelial tumors in D. melanogaster. In conclusion, in these experimental conditions, the cola and orange base soft drinks demonstrated carcinogenic potential in somatic cells of D. melanogaster in the concentration of 3.33 mL/g.
Refrigerantes são bebidas industrializadas não fermentadas, livre de álcool, carbonatadas, ricas em aromas artificiais e açúcar. O consumo intenso dessas bebidas pode estar relacionada à doenças não herdáveis como, cáries, quadros alérgicos, formação de celulite e estrias cutâneas, alterações gastrointestinais, diabetes e câncer. O objetivo desse trabalho foi avaliar o potencial carcinogênico de diferentes concentrações de refrigerantes produzidos no município de Uberlândia, Estado de Minas Gerais, Brasil. Foi realizado o Teste de Detecção de Tumor Epitelial em Drosophila melanogaster. Larvas de terceiro estágio descendentes do cruzamento entre fêmeas virgens wts/TM3, sb¹ e machos mwh/mwh de D. melanogaster foram tratadas com diferentes concentrações (0,83; 1,66 ou 3,33 mL/g) de refrigerantes à base de cola, diet cola, laranja e limão. Os resultados mostraram aumento na frequência de tumor epitelial em moscas tratadas 3,33 mL/g de refrigerantes à base de cola e de laranja, quando comparados ao controle negativo. Os refrigerantes diet cola e limão não provocaram aumento na frequência de tumor epitelial em D. melanogaster. Em conclusão, nessas condições experimentais, os refrigerantes à base de cola e laranja mostraram potencial carcinogênico em células somáticas de D. melanogaster na concentração de 3,33 mL/g.
Assuntos
Verrugas , Bebidas Gaseificadas , Drosophila melanogaster , Testes de MutagenicidadeRESUMO
Na cultura da soja, o déficit hídrico é um dos fatores limitantes à obtenção da máxima produtividade. A identificação de genótipos com capacidade de tolerância à seca é fundamental para a solução desse problema. Objetivou-se, neste trabalho, analisar a qualidade fisiológica e as respostas bioquímicas de cultivares de soja (MG/BR 46 Conquista, UFUS Carajás, UFUS Impacta, UFUS Riqueza e UFUS Xavante) submetidas ao estresse hídrico com soluções de PEG 6000 em diferentes níveis de potencial osmótico (0; -0,1; -0,2; -0,3 e -0,4 MPa). Avaliou-se a qualidade fisiológica das cultivares por meio dos testes de comprimento de plântulas e biomassa fresca e seca de plântulas. As respostas bioquímicas foram avaliadas pela detecção do ácido indol-acético, pelo conteúdo de sacarose e pelo transporte de água nas plântulas. A cultivar UFUS Riqueza apresentou os melhores desempenhos nos testes de qualidade fisiológica, conteúdo de sacarose, absorção e velocidade de absorção de água em plântulas. A cultivar UFUS Xavante mostrou a maior concentração de AIA e o maior massa de plântulas no teste de transporte de água.
In soybean culture water deficit is one of the most limiting factors to the maximum yield obtained. Genotypes identification with drought tolerance capacity is fundamental to solve this problem. The objective in this paper was analyze the physiological quality and physiological and biochemical responses of soybeans cultivars (MG/BR 46 Conquista, UFUS Carajás, UFUS Impacta, UFUS Riqueza and UFUS Xavante) submitted to water stress with PEG 6000 solutions in different levels of osmotic potentials (0; -0,1; -0,2; -0,3 and -0,4 MPa). Physiological quality of cultivars were evaluated by seedling length test and fresh and dry biomass. The biochemical responses were evaluated by detection of indol-acetic acid (IAA), by saccharose content and seedling water transportation. UFUS Riqueza presented the best performance in physiological quality tests, saccharose content, absorption and water absorption velocity in seedling. UFUS Xavante showed the highest IAA's concentration and the greater weight of seedling in water transportation test.
Assuntos
Glycine max , Produção Agrícola , Secas , Irrigação AgrícolaRESUMO
Caryocar brasiliense (pequi), is one of the main species at the biome of the Brazilian savannah due to its use in culinary, popular medicine, industry in general, and iron and steel industry. At São José do Xingu (MT), a tree of C. brasiliense without thorn at the endocarp was found, which enables the improvement of C. brasiliense not only for consumption but also to the high appreciation it already has. To detect the existing differences between the pequi with and without the thorn at the endocarp, RADP markers were used. The generated polymorphisms were cloned and sequenced in order to identify the sequences that are responsible for the fenotypical alteration. It was observed that the pequi without thorn is genetically isolated from the other populations of pequi with thorn at the endocarp, proving that this characteristic is related to the genetic divergence of the species. Analysis in BLASTn evidenced the similarity of the Dof1 genes of Zea mays to its gene of phosphinotricin acetyl transferase. In the analysis of BLASTx, the similarity was verified to the proteins responsible for the deficiency in ferric reductase 4, and catalase.
Pequi, Caryocar brasiliense, é uma das espécies de destaqueno bioma do cerrado brasileiro, devido a sua utilização na medicina, na culinária popular, indústria em geral, e na do ferro e do aço. Na região de São José do Xingu (MT), uma árvore de pequi sem espinho no endocarpo foi encontrado e isso permite melhorar pequi não só para o consumo, aproveitando a alta apreciação que já possui. Para detectar as diferenças existentes entre o genoma de pequi com e sem espinho no endocarpo, marcadores moleculares RAPD foram utilizados. Os polimorfismos gerados foram clonados e sequenciados, a fim de identificar as sequências responsáveis pela alteração fenotípica. Observou-se que o pequi sem espinho é geneticamente isolado de outras populações de pequi com espinho no endocarpo, provando que essa característica está relacionada com a divergência genética da espécie. Análise em Blastn evidenciou a similaridade dos genes Dof1 e com o gene da fosfinotricina-acetiltransferase de Z. mays. Na análise da BLASTx, a similaridade foi verificada com as proteínas responsáveis pela deficiência de ferro 4 redutase e catalase.
Assuntos
DNA de Plantas/genética , Genoma de Planta/genética , Polimorfismo Genético/genética , Ericales/genética , Técnica de Amplificação ao Acaso de DNA Polimórfico , Ericales/anatomia & histologia , Ericales/classificaçãoRESUMO
A ocorrência de Aethalion reticulatum, Linnaeus, 1767 (Hemiptera: Aethalionidae) ou cigarrinha do pedúnculo, em manga Mangifera indica (Anacardiaceae), já foi relatada em diversos estados do país. Algumas relações aparentemente comensais podem ocorrer entre cigarrinhas e abelhas sem ferrão, principalmente Trigona spinipes. Nessetrabalho, analisamos a interação entre a abelha Trigona spinipes Fabricius, 1793 (Hymenoptera: Apidae) e a cigarrinha dopedúnculo A. reticulatum, em mangueira. Os comportamentos de T. spinipes defendendo e estimulando a cigarrinha para obter honeydew foram observados e descritos. Essa associação é mutuamente benéfica, sem implicar necessariamente dependência ou interdependência obrigatória. Todavia, a intensa atividade de abelhas solicitando honeydew pode aumentar o consumo de seiva pelas cigarrinhas prejudicando ainda mais o desenvolvimento normal das frutas.
The occurence of Aethalion reticulatum, Linnaeus, 1767 (Hemiptera: Aethalionidae) in mangoMangifera indica (Anacardiaceae), has been reported in many states of this country. Some apparently commensal relations can occur beteween A. reticulatum and stingless bees, specially Trigona. In this work, we analyzed the interaction between Trigona spinipes Fabricius, 1793 (Hymenoptera: Apidae) and A. reticulatum. The defense behaviour as well the stimulation of A. reticulatum by the bee in order to obtain honeydew, were observed and described. This association is mutually beneficial, without implicate in an obligatory dependence or interdependence. However, the intense solicitation of honeydew by the bees can increase the sap consumption what prejudice the fruit production even more.
Assuntos
Animais , Abelhas , Hemípteros , Insetos , MangiferaRESUMO
Existem poucos estudos acerca da qualidade e da constituição do alimento larval das abelhas sem ferrão. O objetivo do presente trabalho foi acrescentar dados sobre as características do alimento larval, que embasem futuras pesquisas sobre a influência da alimentação das larvas na determinação de castas no gênero Melipona. Um favo recém construído foi retirado de uma colônia forte de Melipona scutellaris e o alimento de 25 alvéolos foram estudados em relação ao volume total de alimento, volume da camada superior e inferior, quantidade e concentração de proteínas eatividades enzimáticas. Ficou evidenciado que o número de variáveis na alimentação larval não se restringe ao volume total (CV=14,19%), mas também, à quantidade de proteínas da camada superior do alimento (CV=13,75%) e, principalmente, de pólen (CV=34,09%). O monitoramento dessas variáveis em diferentes estações do ano pode fornecer pistas sobre quais elementos da alimentação são refletidos na proporção de rainhas produzidas.
There are few studies on the quality and constitution of larval food of stingless bees. The present study was performed to increase the knowledge about the characteristics of larval food. This knowledge can be used in the future to investigate the influence of larval nourishment on the caste determination of Melipona. One recently built comb was removed from a strong colony of Melipona scutellaris and the larval food of 25 brood cells was studied individually. We analyzed the total volume of the larval food, the volume of its superior and inferior layers, the quantity and concentration of proteins, and also the enzymatic activities. The variation among the brood cells was very high, not only concerning the total volume of larval food (CV=14,19%), but also the quantity of proteins (CV=13,75%) and, mainly, the quantity of pollen (CV=34,09%). Monitoring these variables through different seasons can give an idea about which elements of larval food can be related to queen production.
Assuntos
Animais , Abelhas , Enzimas , Himenópteros , Larva , PólenRESUMO
Changes in hormonal levels can produce alternative phenotypes. Juvenile hormone III plays an importantrole in the regulation of metamorphosis, caste determination and age in bees. In this work, we examined theultrastructure of corpora allata cells from stingless bees (Melipona quadrifasciata) treated with juvenilehormone during development. The corpora allata cells of M. quadrifasciata queens showed greater activitythan those of workers. The topical application of juvenile hormone III altered the cellular ultrastructureand either delayed development (as shown by fewer mitochondria and greater chromatin condensation) orenhanced development (looser chromatin and numerous mitochondria) when compared to untreated (control)bees. Our results show that corpora allata cells differ in their ultrastructural characteristics and that thecessation of juvenile hormone production by these cells in M. quadrifasciata is not synchronous.
Assuntos
Animais , Abelhas , Corpora Allata , Corpora Allata/anatomia & histologia , Hormônios de Inseto , Hormônios/análise , Hormônios/fisiologiaRESUMO
The objective of the present study was to determine by differential display reverse transcriptase-polymerase chain reaction (DDRT-PCR) the effects of juvenile hormone (JH) III applied during the late larval 3 (L3) phase on gene expression in Melipona scutellaris. A temporal window of expression of feminizing genes exists during the late L3 and pre-defecating larval phases when these genes can be turned on or off by the action of JH, which is able to mediate the differentiation of female larvae into queens. Combination of the HT11A-AP4 primers revealed differential expression in L3 individuals treated with JH III for 1 h, with weak expression of the transcript, while intense expression was observed for controls and individuals treated for 4 h. Combination of the HT11G-AP4 and HT11G-AP5 primers showed suppression of the gene products for each primer combination in 1-h treated larvae compared to untreated control individuals of the same age and individuals treated for 4 h. Differential gene expression was also observed during development. These results demonstrate that the JH III may suppress or alter gene expression profiles during phase L3 of M. scutellaris.
Assuntos
Abelhas , Expressão Gênica , Hormônios Juvenis , Reação em Cadeia da PolimeraseRESUMO
Nesse estudo nós usamos a técnica de Differential Display Reverse Transcriptase - Polymerase Chain Reaction (DDRT-PCR) para comparamos o perfil de mRNA em Melipona scutellaris durante o desenvolvimento ontogenético pós-embrionário e em operárias adultas, rainha natural e induzida pelo Hormônio Juvenil III. Fragmentos diferencialmente expressos foram detectados usando as seguintes combinações de primers: HT11G-AP05; HT11C-AP05; HT11G-OPF12; HT11G-OPA16. Dos 9 ESTs descrito nesse trabalho, 6 tiveram expressão diferencial nas fases de larva L1 e L2, sugerindo serem mecanismos chave no regulação do desenvolvimento larval em Melipona. A combinação HT11G-AP05 revelou em L1 e L2 um produto com similaridade à proteína tioredoxina redutase de Clostridium sporogenes, uma proteína importante durante os processos de oxidoredução. Esse estudo representa as primeiras evidências moleculares do perfil de expressão durante o desenvolvimento ontogenético em abelhas do gênero Melipona.
Assuntos
Animais , Feminino , Abelhas/genética , Etiquetas de Sequências Expressas , Regulação da Expressão Gênica no Desenvolvimento/genética , Hormônios Juvenis/genética , RNA Mensageiro/genética , Sequência de Bases , Abelhas/crescimento & desenvolvimento , Perfilação da Expressão Gênica , Larva/genética , Larva/crescimento & desenvolvimento , Dados de Sequência Molecular , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodosRESUMO
The cattle tick Boophilus microplus causes great damage in livestock and is considered one of the most important tropical ectoparasites. The traditional method of control is based on the intensive use of pesticides, however the indiscriminate use of these compounds over the years has led to the selection of resistant ticks. Hydrolases, particularly esterases (EST), have been reported to be associated with acaricide resistance in B. microplus. We compared the esterase profile of susceptible and cypermethrin-resistant strains of adult B. microplus and a pyrethroid susceptible reference strain (the Mozzo strain) using polyacrylamide gel electrophoresis and specific staining. The electrophoretic profiles of protein extracts revealed the presence of four regions with esterase activity in the cypermethrin-resistant strain and three of these regions in the susceptible strains. The bands were numbered EST-1 to EST-4 in sequence (starting from the anode) according to their decrease in negative charge. The EST-1A and EST-1B enzymes were detected only in the resistant strain. The inhibition studies with eserine sulfate, copper sulfate, p- p-chloromercuribenzoate (pCMB), malathion and phenylmethylsulfonyl fluoride (PMSF) indicated that the EST-1A and EST-1B enzymes belong to the acetylcholinesterase class and are probably associated with resistance to acaricides in this Brazilian resistant strain of B. microplus.
Assuntos
Animais , Inseticidas/farmacologia , Carrapatos , Bovinos , Doenças dos Bovinos/parasitologia , Resistência a Inseticidas , Controle de Ácaros e CarrapatosRESUMO
A técnica de Low Ionic Strength Single-Strand Conformation Polymorphism (LIS-SSCP) foi desenvolvida, como forma de detectar mutação em fita simples de DNA. Esta técnica consiste basicamente na separação de fragmentos de DNA de fita simples por desnaturação, por meio de uma solução de baixa força iônica (LIS) a base de sacarose. Utilizou-se a técnica de LIS-SSCP para estudar populações de Melipona scutellaris Latreille, 1811 quanto à presença de variações do 16S mtDNA. Estas populações foram introduzidas no Meliponário Uberlândia, Uberlândia-MG, em diferentes período de tempo, colônias K (introduzidas em 1987) e colônias AB e N (introduzidas em 1999 e 2000 respectivamente). Os resultados não mostraram variações no 16S mtDNA entre as colônias K e colônias AB e N, embora houvesse nítidas diferenças morfológicas e comportamentais entre elas.
The Single Strand Conformation Polymorphim (SSCP) is a technique that was developed to detect mutations in single strande DNAs. This technique consistes in separating the single strand DNA fragments by their desnaturation using a low ionic stregth (LIS) solution which is composed of sucrose. We use the LIS-SSCP technique with the purpose to study populations of Melipona scutellaris Latreille, 1811, about the presence of 16SmtDNA variations. The populations were introduced in the Uberlândia Meliponary (Uberlândia-MG, Brazil) in different periods of time, colonies K (introduced in 1987) and colonies AB and N (introduced in 1999 and 2000 respectively). The results had not shown variations between the colonies K, AB and N, although in had clear morphologic and behavioral difference between these colonies.
Assuntos
Animais , Abelhas , DNA Mitocondrial , Polimorfismo Genético , Polimorfismo Conformacional de Fita SimplesRESUMO
O objetivo dessa investigação foi estudo caso-controle para verificar o impacto do uso de antibióticos, clorexidina e mercúrio sobre a resistência de enterobactérias isoladas da cavidade oral. Quatro grupo de dez voluntários foram testados: A - Indivíduos com várias restaurações á amálgama. B - Indivíduos em uso de antimicrobianos. C - Indivíduos em uso de digluconato de clorexidina a 0,12 por cento em Indivíduos em bochechos diários e D - Indivíduos sem história de cárie dentária(Controle). Os indivíduos foram monitorados microbiologicamente por quatro semanas. A resistência foi determinada in vitro pelas técnicas de difusão em gel e diluição em agar. O experimento de transferência de resistência foi realizado utilizando as técnicas de cultura em caldo e filtragem por membrana, usando como receptora E. coli K12. Significante colonização por enterobactérias foi detectada no grupo em uso de antimicrobianos (50 por cento). A espécie mais frequente foi E. coli, com 54,5 por cento, sendo que um terço dessas mostrou multirresistência. No grupo B a concentração inibitória mínima (CIM) para a gentamicina foi de 64 mg/mL, enquanto no grupo Controle foi de 4 mg/mL. Todas as amostras apresentaram resistência tanto para clorexidina como para o cloreto de mercúrio. O CIM calculado pelo E test foi similar ao de diluição em agar. Os experimentos de conjugação mostraram 87,5 por cento de sucesso, em sete de oito efetuados, contudo, somente dois transconjugantes mostraram as duas marcas de resistência
Assuntos
Humanos , Masculino , Feminino , Antibacterianos/farmacologia , Clorexidina , EnterobacteriaceaeRESUMO
A aplicaçäo de Hormônio Juvenil I, II e III em doses simples ou fracionadas sobre larvas de Melipona compressipes, M. quadrifasciata, M. rufiventris e M. scutellaris, quando estas estäo nas fases de L3 e no início da fase de tecelagem dos casulos (larvas pré-defecantes - LPD) ativa os genes feminizantes induzindo diferenciaçäo das larvas fêmeas em rainhas. A técnica de fracionar as dosagens demonstrou ser eficiente em Melipona para a produçäo de rainhas. E difícil obter 100 por cento de rainhas com uma única dose de HJ em algumas espécies, o que implica em um mecanismo de degradaçäo do HJ por esterase específica; 100 por cento de produçäo ocorre somente quando a quantidade adequada de HJ é administrada dentro do período larval que é crítico para a determinaçäo de casta. A dose limite de HJ I para M. compressipes (abaixo da qual näo é possível obter 100 por cento de rainhas) foi de 0,1µg HJ I em 4 aplicaçöes de 0,025µg cada. Para Melipona quadrifasciata a dose limite para se atingir a proporçäo máxima de rainhas foi de 0,2µg HJ I em 4 aplicaçöes de 0,05µg cada. Para M. scutellaris a dose de 0,025µg de HJ I/µl em dose única determinou 100 por cento de rainhas. Näo foi obtido 100 por cento de rainhas em M. rufiventris e dose única de 0,2µg HJ I/µl produziu 86 por cento de rainhas. A fim de se obter a expressäo dos genes feminizantes em espécies de Melipona, o HJ I foi o mais eficiente, seguido do HJ III. Cada espécie responde diferentemente a doses de HJ e estas necessitam ser testadas e aferidas antes de uso.