The search for novel insecticide targets in the post-genomics era, with a specific focus on G-protein coupled receptors

Insects are considered pests globally, implicated in the destruction of agricultural fields and transmission of pathogens that cause deadly human diseases, such as dengue, Zika and malaria. The diversity of the insecticide arsenal has remained stagnant for decades, but the recent rise of insecticide resistance fueled the discovery of novel modes of action, and the power of genomics has reinvigorated this search. This review discusses the importance of comparative and functional insect genomics in the identification of potential gene targets for an insecticidal mode of action with low off-target toxicity. Due to the global participation in the sequencing and annotation of insect genomes, the targeting of specific genes with molecular tools like RNAi and CRISPR/Cas9 for genome engineering and consequent functional identification and validation has become more efficient. While there are multiple avenues to explore for insecticidal candidates, this review identifies G-protein coupled receptors as attractive targets, and hones in on the octopamine and dopamine receptors due to their potential.

Relationship between Neutrophil-To-Lymphocyte Ratio and Electrocardiographic Ischemia Grade in STEMI / Associação entre a Relação Neutrófilos/Linfócitos e o Grau de Isquemia Eletrocardiográfica no IAMEST

Background: Neutrophil-to-lymphocyte ratio (NLR) has been found to be a good predictor of future adverse cardiovascular outcomes in patients with ST-segment elevation myocardial infarction (STEMI). Changes in the QRS terminal portion have also been associated with adverse outcomes following STEMI. Objective: To investigate the relationship between ECG ischemia grade and NLR in patients presenting with STEMI, in order to determine additional conventional risk factors for early risk stratification. Methods: Patients with STEMI were investigated. The grade of ischemia was analyzed from the ECG performed on admission. White blood cells and subtypes were measured as part of the automated complete blood count (CBC) analysis. Patients were classified into two groups according to the ischemia grade presented on the admission ECG, as grade 2 ischemia (G2I) and grade 3 ischemia (G3I). Results: Patients with G3I had significantly lower mean left ventricular ejection fraction than those in G2I (44.58 ± 7.23 vs. 48.44 ± 7.61, p = 0.001). As expected, in-hospital mortality rate increased proportionally with the increase in ischemia grade (p = 0.036). There were significant differences in percentage of lymphocytes (p = 0.010) and percentage of neutrophils (p = 0.004), and therefore, NLR was significantly different between G2I and G3I patients (p < 0.001). Multivariate logistic regression analysis revealed that only NLR was the independent variable with a significant effect on ECG ischemia grade (odds ratio = 1.254, 95% confidence interval 1.120–1.403, p < 0.001). Conclusion: We found an association between G3I and elevated NLR in patients with STEMI. We believe that such an association might provide an additional prognostic value for risk stratification in patients with STEMI when combined with standardized risk scores. .

Fundamento: A relação neutrófilos/linfócitos (N/L) tem sido descrita como boa preditora de eventos cardiovasculares adversos futuros em pacientes com infarto agudo do miocárdio com elevação do segmento ST (IAMEST). Mudanças na porção terminal do complexo QRS também têm sido associadas a eventos adversos após IAMEST. Objetivo: Investigar a associação entre o grau de isquemia no ECG e a relação N/L em pacientes com IAMEST para determinar fatores de risco convencionais adicionais na estratificação precoce de risco. Métodos: Pacientes com IAMEST foram investigados. O grau de isquemia foi analisado a partir do ECG obtido à admissão. A contagem de leucócitos e seus subtipos foi realizada a partir de hemograma automatizado. De acordo com o grau de isquemia presente no ECG de admissão, os pacientes foram classificados em dois grupos, isquemia grau 2 (IG2) e isquemia grau 3 (IG3). Resultados: Pacientes com IG3 apresentaram valores médios significativamente menores de fração de ejeção do ventrículo esquerdo do que os pacientes com IG2 (44,58 ± 7,23 versus 48,44 ± 7,61; p = 0,001). Como esperado, a taxa de mortalidade intra-hospitalar aumentou proporcionalmente com o aumento no grau de isquemia (p = 0,036). Houve diferenças significativas nas porcentagens de linfócitos (p = 0,010) e de neutrófilos (p = 0,004) e, portanto, a relação N/L diferiu significativamente entre pacientes com IG2 e IG3 (p < 0,001). À análise de regressão logística multivariada, apenas a relação N/L emergiu como variável independente com efeito significativo sobre o grau de isquemia no ECG (odds ratio = 1,254; intervalo de confiança de 95% 1,120-1,403; p < 0,001). Conclusão: Nós encontramos uma associação entre IG3 e relação N/L aumentada em pacientes com IAMEST. Acreditamos que esta associação possa oferecer um valor prognóstico adicional para estratificação de risco em pacientes com IAMEST quando usado em combinação com escores de risco padronizados. .

O subgênero Culex na América do Sul (Diptera: Culicidade) / The subgenus Melanoconion of Culex (Diptera: Culicidae) in South America

Introdução - Algumas espécies de Culex (Melanoconion) são consideradas vetores de vírus do complexo da Encefalite Equina Venezuelana e do Vírus do Nilo Ocidental. O subgênero Melanoconion é considerado grupo taxonômico diverso, amplamente distribuído nos países do continente americano, com exceção do Chile e Canadá. A diferenciação das espécies implica grande dificuldade taxonômica, dependendo de estudos dos caracteres morfológicos da genitália dos machos. Contudo o estudo da genitália masculina demanda destreza na dissecção das respectivas estruturas. A classificação atual do subgênero inclui 160 espécies distribuídas em dois grupos principais, a Seção Melanoconion e a Seção Spissipes. Estas seções estão subdivididas em agrupamentos não formais que foram propostos de maneira a englobar as espécies morfologicamente semelhantes, em especial por caracteres da genitália masculina. Objetivos - Investigar as relações filogenéticas entre as espécies do subgênero, e testar a classificação atual proposta por Sirivanakarn (1983). O estudo avaliou o monofiletismo das seções Melanoconion e Spissipes, e de alguns agrupamentos incluídos em cada uma. Métodos - A partir de amostra composta por 106 espécimes do subgênero (46 espécies) e empregando fragmentos de dois genes nucleares de cópia única (CAD, HB), e do gene mitocondrial (COI), foram propostas hipóteses sobre relações filogenéticas. As análises filogenéticas empregaram os métodos estatísticos de Máxima Verossimilhança e de análise Bayesiana. Resultados e Discussão - Apresenta-se a primeira hipótese filogenética de espécies do subgênero Melanoconion baseada informações de três genes. Os resultados obtidos corroboram o monofiletismo das duas seções. As espécies incluídas na Seção Spissipes estão subdivididas em grupos que refletem a história evolutiva e, portanto, correspondem a grupos naturais que compartilham ancestral comum. Portanto, propomos a revalidação do subgênero Helcoporpa Dyar transferindo para ele todas as espécies até agora incluídas na Seção Sipissipes, com exceção do Culex nicaroensis. Por outro lado, a Seção Melanoconion é formada por grupos monofiléticos e outros grupos polifiléticos ou parafiléticos. Este fato sugere que serão necessários rearranjos taxonômicos na Seção Melanoconion, além de estudos mais abrangentes tanto em relação à amostra de espécies como outros genes. Os resultados aqui descritos mostram que o gene COI pode ser utilizado como ferramenta complementar para facilitar a identificação taxonômica das espécies de Melanoconion. Adicionalmente, os genes nucleares, quando analisados em conjunto, proporcionaram informação suficiente na diferenciação de seções, grupos não formais e espécies do subgênero. O uso dos três marcadores moleculares é recomendado para estudo da filogenia de Culex (Melanoconion). Este estudo contribui com informação nova e útil para melhor compreender a classificação de Melanoconion e auxiliar na identificação das espécies.

Introduction - Some of the species of Culex (Melanoconion) Theobald are recognized as vectors of arboviruses such as Venezuelan Equine Encephalitis Virus complex and West Nile Virus. Melanoconion is considered taxonomically diverse and widely distributed in the Americas, with the exception of Chile and Canada. The species of this subgenus pose a real taxonomical challenge as the identification based on morphological traits focuses mainly on the male genitalia that require well-trained skills for dissection of the structures. The current classification of the subgenus recognizes 160 species divided in two major groups, Melanoconion Section and Spissipes Section. Each one of these sections are further divided into non-formal groupings proposed to include morphologically similar species, mainly based on male genitalia characters. Research objectives - To investigate phylogenetic relationships between species of the subgenus Melanoconion of Culex by testing the current classification by Sirivanakarn (1983). We intended to evaluate the monophyly of the two major sections of the subgenus and some of the non-formal groups included in each section. Methods - Our sample taxa included 106 specimens of Melanoconion (46 species), from which we used fragments of two single-copy nuclear genes (CAD, HB) and the mitochondrial gene COI. We raised phylogenetic hypotheses about the subgenus Melanoconion based on analyses that used statistical methods such as Maximum likelihood and Bayesian inference. Results and Discussion - We present the first molecular phylogeny of Melanoconion based on information provided by three genes. The obtained phylogenetic trees strongly support that both sections, Melanoconion and Spissipes, are monophyletic groups. Furthermore the Spissipes Section showed phylogenetic lineages consistent with morphological classification. Thus we strongly recommend the resurrection of subgenus Helcoporpa Dyar to include species until now considered as Spissipes Section, with the exception of Culex nicaroensis. As for the Melanoconion Section, several non-formal groupings corresponded to polyphyletic or paraphyletic groups, with only a few having monophyletic origins. This fact suggests that future taxonomic rearrangements should be consider for Melanoconion Section, as well as a wider sampling of species and molecular markers. Our results confirmed the use of COI gene as a complementary tool for taxonomical identifications. Additionally, the performance of nuclear genes, when analyzed together, was highly informative, showing resolution between the two sections and also for species level. As for tools to infer phylogeny, our data are in agreement with the use of multi loci approach, in order to propose a phylogenetic hypothesis. Our results contribute with new information that improves the classification of subgenus Melanoconion and provides useful data to help with the identification tasks.

A possible role of Drosophila CTCF in mitotic bookmarking and maintaining chromatin domains during the cell cycle

BACKGROUND: The CCCTC-binding factor (CTCF) is a highly conserved insulator protein that plays various roles in many cellular processes. CTCF is one of the main architecture proteins in higher eukaryotes, and in combination with other architecture proteins and regulators, also shapes the three-dimensional organization of a genome. Experiments show CTCF partially remains associated with chromatin during mitosis. However, the role of CTCF in the maintenance and propagation of genome architectures throughout the cell cycle remains elusive. RESULTS: We performed a comprehensive bioinformatics analysis on public datasets of Drosophila CTCF (dCTCF). We characterized dCTCF-binding sites according to their occupancy status during the cell cycle, and identified three classes: interphase-mitosis-common (IM), interphase-only (IO) and mitosis-only (MO) sites. Integrated function analysis showed dCTCF-binding sites of different classes might be involved in different biological processes, and IM sites were more conserved and more intensely bound. dCTCF-binding sites of the same class preferentially localized closer to each other, and were highly enriched at chromatin syntenic and topologically associating domains boundaries. CONCLUSIONS: Our results revealed different functions of dCTCF during the cell cycle and suggested that dCTCF might contribute to the establishment of the three-dimensional architecture of the Drosophila genome by maintaining local chromatin compartments throughout the whole cell cycle.

Omics of vector mosquitoes: a big data platform for vector biology and vector-borne diseases / 南方医科大学学报

Recently the studies on mosquito genomics, transcriptomics and small RNAomics developed rapidly with the novel biotechnologies of the next generation sequencing techniques. The genome sequences of several important vector mosquitoes including Anopheles gambiae, Culex quinquefasciatus, and Aedes aegypti have been published. The genome sizes vary among the different species of mosquitoes and are consistent with the number of the repeat regions. The released genome sequences facilitate gene cloning and identification as for OBP, OR and dsx genes. Transcriptomics provides a useful tool for functional analyses of the mosquito genes, and using this technique, the molecular basis of mosquito blooding, gland proteins and diapauses have been explored. Studies on small RNAomics suggest important roles of miRNAs and piRNAs in ovary development, blood digestion, and immunity against virus infection. The studies on mosquito omics have generated a big data platform for investigation of vector biology and vector-transmitted disease prevention.

Genetic basis of triatomine behavior: lessons from available insect genomes

Triatomines have been important model organisms for behavioural research. Diverse reports about triatomine host search, pheromone communication in the sexual, shelter and alarm contexts, daily cycles of activity, refuge choice and behavioural plasticity have been published in the last two decades. In recent times, a variety of molecular genetics techniques has allowed researchers to investigate elaborate and complex questions about the genetic bases of the physiology of insects. This, together with the current characterisation of the genome sequence of Rhodnius prolixus allows the resurgence of this excellent insect physiology model in the omics era. In the present revision, we suggest that studying the molecular basis of behaviour and sensory ecology in triatomines will promote a deeper understanding of fundamental aspects of insect and, particularly, vector biology. This will allow uncovering unknown features of essential insect physiology questions for a hemimetabolous model organism, promoting more robust comparative studies of insect sensory function and cognition.

Detection of diploid males in a natural colony of the cleptobiotic bee Lestrimelitta sp (Hymenoptera, Apidae)

When working at quantifying the genome size of stingless bees, it was observed that males of Lestrimelitta sp possessed the same amount of nuclear DNA as the females. Thus, we used flow cytometry (FCM) and cytogenetic analysis to confirm the ploidy of these individuals. The males analyzed proved to be diploid, since, through cytometric analysis, it was demonstrated that the mean genome size of both males and females was the same (C = 0.463 pg), and, furthermore, cytogenetic analysis demonstrated that both had 2n = 28 chromosomes.

Mitochondrial genome differences between the stingless bees Melipona rufiventris and Melipona mondury (Apidae: Meliponini)

Within the Meliponini, a widely distributed group of stingless bees, Melipona rufiventris has been considered as a single, cohesive species. Recently, analysis of morphological characters led to the splitting of this species into two species, M. mondury and M. rufiventris. The former occurs in the Atlantic Rain Forest ranging from Santa Catarina to Bahia States, while the latter is found in other parts of Brazil. We used PCR + RFLP to identify genetic marker patterns of the mtDNA between these species. Nine mtDNA regions were amplified and digested with four restriction enzymes (EcoRI, EcoRV, HindIII, and HinfI). Six species-specific restriction sites were identified for M. mondury and M. rufiventris with all enzymes, except for HindIII. The molecular data agree with the morphological classification.