Circular RNA ame_circ_000115 regulates expression of genes in larval gusts of Apis mellifera ligustica stressed by Ascosphaera apis / 生物工程学报

Circular RNAs (circRNAs) are a new class of non-coding RNAs, which have been confirmed to regulate insect gene expression and immune response through multiple manners such as competing endogenous RNA (ceRNA) regulatory network. Currently, function of circRNA in honey bee immune response remains unclear. In this study, PCR and Sanger sequencing were performed to validate the back splicing (BS) site of ame_circ_000115 (in short ac115). RT-qPCR was used to detect the expression profile of ac115 in larval guts of Apis mellifera ligustica stressed by Ascosphaera apis. Dual-luciferase reporter gene assay was conducted to verify the binding relationship between ac115 and ame-miR-13b. Interference of ac115 in larval guts was carried out by feeding specific siRNA, followed by determination of the effect of ac115 interference on expression of six genes relevant to host immune response. The results confirmed the existence of BS site within ac115. Compared with the un-inoculated group, the expression of ac115 in 4-day-old larval gut of the A. apis-inoculated group was up-regulated with extreme significance (P < 0.000 1), while that in 5- and 6-day-old larval guts were significantly up-regulated (P < 0.05). The brightness of specific band for ac115 in 4-, 5- and 6-day-old larval guts of the siRNA-circ_000115-fed group gradually became weak, whereas that of the siRNA-scrambl-fed group was pretty high without obvious variation. Compared with that of the siRNA-scramble-fed group, the expression of ac115 in 4-day-old larval gut of the siRNA-circ_000115-fed group was significantly down-regulated (P < 0.05), whereas that of the 5- and 6-day-old larval guts were down-regulated with extreme significance (P < 0.001). Ame-miR-13b was truly existed and expressed in A. m. ligustica larval guts, and there was true binding relationship between ac115 and ame-miR-13b. Compared with that of the siRNA-scramble-fed group, the expression of antimicrobial peptide genes hymenoptaecin and abaecin in 6-day-old larval gut of the siRNA-circ_000115-fed group was significantly up-regulated (P < 0.05), while that of ecdysone receptor (Ecr) was down-regulated with extreme significance (P < 0.01). These results indicate that ac115 is truly expressed in A. m. ligustica larval guts, BS site truly exists within ac115, and effective interference of ac115 in A. m. ligustica larval guts can be achieved via feeding siRNA. Moreover, ac115 potentially regulates Ecr expression through adsorption of ame-miR-13b and expression of hymenoptaecin and abaecin using a non-ceRNA manner, further participating in host stress-response.

Genetic parameters for weight, morphometry and oviposition of Africanized honeybee queens using simulated data / [Parâmetros genéticos para peso, morfometria e oviposição de abelhas rainhas africanizadas sob simulação]

This study aimed to estimate genetic parameters for simulated data of body weight (BW), abdominal width (AW), abdominal length (AL), and oviposition. Simulation was performed based on real data collected at apiaries in the region of Campo das Vertentes, Minas Gerais, Brazil. Genetic evaluations were performed using single- and two-trait models and (co)variance components were estimated by the restricted maximum likelihood method. The heritability for BW, AW, AL and oviposition were 0.54, 0.47, 0.31 and 0.66, respectively. Positive genetic correlations of high magnitude were obtained between BW and AW (0.80), BW and oviposition (0.69), AW and oviposition (0.82), and AL and oviposition (0.96). The genetic correlations between BW and AL (0.11) and between AW and AL (0.26) were considered moderate and low. In contrast, the phenotypic correlations were positive and high between BW and AW (0.97), BW and AL (0.96), and AW and AL (0.98). Phenotypic correlations of low magnitude and close to zero were obtained for oviposition with AL (0.02), AW (-0.02), and BW (-0.03). New studies involving these characteristics should be conducted on populations with biological data in order to evaluate the impact of selection on traits of economic interest.(AU)

Objetivou-se estimar parâmetros genéticos para dados simulados de peso corporal (PC), largura abdominal (LA), comprimento abdominal (CA) e oviposição (OV). A simulação foi conduzida com base em dados reais, coletados em apiários da região do Campo das Vertentes, Minas Gerais. As estimativas das análises genéticas foram realizadas por modelos uni e bicaracterísticos, sendo os componentes de (co) variância estimados pelo método da máxima verossimilhança restrita. As herdabilidades para PC, LA, CA e OV foram de 0,54, 0,47, 0,31 e 0,66 respectivamente. As correlações genéticas foram positivas e de alta magnitude para PC e LA (0,80), PC e OV (0,69), LA e OV (0,82) e CA e OV (0,96). Para PC e CA (0,11) e LA e CA (0,26), as correlações genéticas foram moderadas e de baixa magnitude. As correlações fenotípicas foram positivas e de alta magnitude para PC e LA (0,97), PC e CA (0,96) e LA e CA (0,98). Para OV e CA (0,02), OV e LA (-0,02) e OV e PC (-0,03), foram encontradas correlações fenotípicas de magnitude baixa e próximas de zero. Novos estudos devem ser realizados em populações com dados biológicos, a fim de se observar o impacto da seleção em características de interesse econômico.(AU)

Correlação de parâmetros biométricos e produtivos em colônias de Melipona scutelaris / Correlation of biometric and productive parameters in colonies of Melipona scutelaris

The objective of this research was to estimate the correlations between the biometric and reproductive parameters of Melipona scutelaris. Four collections were performed with 30-day intervals, consisting of the evaluation of each colony, considering the following parameters: honey pot size and volume (HPS and VHP), estimated honey production (EHP), number of combs (NC), mean diameter of the combs (MDC), height of the combs (HC), height of rearing cells (HRC), number of pups (NP) population (POP) and wax envelope in pups. The data were analyzed using the SAS software (2004), and the Pearson correlation coefficient was used for the correlation calculations. The correlations of the studied variables of production and biometrics of Melipona scutellaris colonies made it possible to perceive that the variable number of honey pots (NHP) present a higher correlation with HPS, EPH, DMC, HRC, NP and POP, followed by size of pots of honey (HPS) with: VHP, EHP, MDC, HC and POP. For future studies using the productive and biometric characteristics of the bees Melipona scutellaris can be considered for EPH, VHP, EPH, NC and POP, as variable responses.(AU)

Parâmetros genéticos para características produtivas e biométricas em abelha Melipona quadrifasciata anthidioides LEPELETIER / Genetic parameters for production and biometrics traits in honey bee Melipona quadrifasciata anthidioides LEPELETIER

Os objetivos deste trabalho foram estimar componentes de variância genética aditiva, fenotípica e residual e a herdabilidade para características relacionadas com a produção de mel e com a estrutura do ninho de abelhas Melipona quadrifasciata anthidioides. Sessenta colônias de diferentes regiões da Bahia foram transladadas para caixas padronizadas modelo INPA e divididas, originando as gerações parentais G1 e G2. Foram medidas as características: estimativa da produção de mel; número, largura, volume e altura dos potes de mel; número, altura e diâmetro dos potes de pólen; peso; número, largura e diâmetro dos discos de cria e estimativa da população da colônia. As medidas foram corrigidas para o efeito fixo de mês de mensuração. Os componentes de variância e herdabilidade foram estimados por meio do método de semelhança entre parentes, utilizando-se abordagem Bayesiana. As médias e os desvios padrão variaram de 2,01±0,70cm para diâmetro de potes de pólen a 2.333,0±384,1kg para o peso das caixas. Houve indicação de convergência para todas as cadeias obtidas. As estimativas de variância genética aditiva variaram de 0,02cm para as características largura dos potes de mel a 38.587,72kg para o peso. Para as estimativas de variâncias fenotípicas, os valores variaram de 0,05 para a altura dos potes de pólen a 95.136,43kg para o peso; e para as variâncias residuais, os valores encontrados variaram de 0,02 para a variável largura dos potes de mel a 56.548,71kg para o peso. As estimativas de herdabilidade variaram de 0,35 a 0,53. Os resultados demonstraram que as características avaliadas possuem variação genética aditiva que garante boa resposta à seleção.

The aim of this study was to estimate components of genetic variance, phenotypic and residual and heritability for traits related to the production of honey and the nest structure of bee Melipona quadrifasciata anthidioides. Sixty colonies from different regions of Bahia were transferred to standard INPA model boxes and divided, creating the parental generations G1 and G2. The following characteristics were measured: estimated production of honey, number, width, height and volume of the honey pots, number, height and diameter of pollen storage pots, weight, number, length and diameter of the brood combs and estimate the population of the colony. The measurements were corrected for the fixed effects of month of measurement. The variance components and heritability were estimated by the method of similarity between relatives using the Bayesian approach. The mean and standard deviations ranged from 2.01±0.70cm diameter pots for pollen to 2333.0±384.1kg to the weight of the boxes. There was indication of convergence for all the chains obtained. Estimates of the additive genetic variance ranged from 0.02cm to the width characteristics of honey pots to 38587.72kg for weight. For the estimates of phenotypic variance the values ranged from 0.05 for the height of the pollen pots to 95136.43kg for weight; and the residual variance the values varied from 0.02 for the variable width of the honey pots to 56548.71kg for weight. The results showed that the characteristics assessed have additive genetic variation that ensures good response to selection.

Transcript levels of ten caste-related genes in adult diploid males of Melipona quadrifasciata (Hymenoptera, Apidae): a comparison with haploid males, queens and workers

In Hymenoptera, homozygosity at the sex locus results in the production of diploid males. In social species, these pose a double burden by having low fitness and drawing resources normally spent for increasing the work force of a colony. Yet, diploid males are of academic interest as they can elucidate effects of ploidy (normal males are haploid, whereas the female castes, the queens and workers, are diploid) on morphology and life history. Herein we investigated expression levels of ten caste-related genes in the stingless bee Melipona quadrifasciata, comparing newly emerged and 5-day-old diploid males with haploid males, queens and workers. In diploid males, transcript levels for dunce and paramyosin were increased during the first five days of adult life, while those for diacylglycerol kinase and the transcriptional co-repressor groucho diminished. Two general trends were apparent, (i) gene expression patterns in diploid males were overall more similar to haploid ones and workers than to queens, and (ii) in queens and workers, more genes were up-regulated after emergence until day five, whereas in diploid and especially so in haploid males more genes were down-regulated. This difference between the sexes may be related to longevity, which is much longer in females than in males.

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.

Karyotypic description of the stingless bee Oxytrigona cf. flaveola (Hymenoptera, Apidae, Meliponina) of a colony from Tangará da Serra, Mato Grosso State, Brazil

The aim was to broaden knowledge on the cytogenetics of the subtribe Meliponina, by furnishing cytogenetic data as a contribution to the characterization of bees from the genus Oxytrigona. Individuals of the species Oxytrigona cf. flaveola, members of a colony from Tangará da Serra, Mato Grosso State, Brazil, were studied. The chromosome number was 2n = 34, distributed among four chromosomal morphologies, with the karyotype formula 8m+8sm+16st+2t. Size heteromorphism in the first metacentric pair, subsequently confirmed by sequential staining with fluorochrome (DA/DAPI/CMA3), was apparent in all the examined individuals The nucleolar organizing regions (NORs) are possibly located in this metacentric chromosome pair. These data will contribute towards a better understanding of the genus Oxytrigona. Given that species in this group are threatened, the importance of their preservation and conservation can be shown in a sensible, concise fashion through studies such as this.

Mitochondrial DNA polymorphism among populations of Meliponaquadrifasciata quadrifasciata Lepeletier (Apidae: Meliponini) from southern Brazil / Polimorfismo do DNA mitocondrial entre populações de Melipona quadrifasciata quadrifasciata Lepeletier (Apidae: Meliponini) do sul do Brasil

The geographical distribution of the Brazilian endemic stingless bee Melipona quadrifasciata quadrifasciata Lepeletier ranges from Rio Grande do Sul to Minas Gerais states. The objective of the present study was to verify mtDNA polymorphisms among samples of M. q. quadrifasciata collected in southern Brazil. Twenty nine colonies from three localities (Blumenau and Mafra/SC and Prudentópolis/ PR) were sampled. Seven mtDNA regions were amplified and further digested with 15 restriction enzymes (PCR-RFLP). Five composite haplotypes were identified, with two unique to samples from Prudentópolis and the remaining three to samples from Mafra and/or Blumenau.

A distribuição geográfica da abelha sem ferrão Melipona quadrifasciata quadrifasciata Lepeletier compreende desde o Rio Grande do Sul até Minas Gerais. O objetivo do presente estudo foi verificar a variabilidade genética em amostras de M. q. quadrifasciata coletadas na Região Sul do Brasil. Para tanto, 29 colônias de três localidades (Blumenau e Mafra/SC e Prudentópolis/PR) foram amostradas e a técnica de PCR-RFLP para o DNA mitocondrial foi utilizada. Sete regiões do genoma mitocondrial foram amplificadas e digeridas com 15 enzimas de restrição. Cinco haplótipos foram identificados: dois exclusivos das amostras de Prudentópolis e os outros três registrados nas amostras de Mafra e/ou de Blumenau.

Sequence and expression pattern of the germ line marker vasa in honey bees and stingless bees

Queens and workers of social insects differ in the rates of egg laying. Using genomic information we determined the sequence of vasa, a highly conserved gene specific to the germ line of metazoans, for the honey bee and four stingless bees. The vasa sequence of social bees differed from that of other insects in two motifs. By RT-PCR we confirmed the germ line specificity of Amvasa expression in honey bees. In situ hybridization on ovarioles showed that Amvasa is expressed throughout the germarium, except for the transition zone beneath the terminal filament. A diffuse vasa signal was also seen in terminal filaments suggesting the presence of germ line cells. Oocytes showed elevated levels of Amvasa transcripts in the lower germarium and after follicles became segregated. In previtellogenic follicles, Amvasa transcription was detected in the trophocytes, which appear to supply its mRNA to the growing oocyte. A similar picture was obtained for ovarioles of the stingless bee Melipona quadrifasciata, except that Amvasa expression was higher in the oocytes of previtellogenic follicles. The social bees differ in this respect from Drosophila, the model system for insect oogenesis, suggesting that changes in the sequence and expression pattern of vasa may have occurred during social evolution.

Analysis of the intercaste transcriptional profile of Melipona scutellaris Latreille, 1811 (Hymenoptera, Apidae, Meliponini) by mRNA differential display

In colonies of Melipona scutellaris Latreille, 1811 workers can be found with four ganglion nerve cells, a morphological characteristic of the queen. It is hypothesized that these workers, called intercastes, or phenocopies, are phenotypically-like workers, but genotypically identical to queens due to this specific trait. Workers with the same number of ganglion as queens seem to be intercastes between queens and workers. Our objective was to analyze the mRNA pro files of workers, queens, and intercastes of M. scutellaris through DDRT-PCR. Three hundred (300) pupae with white eyes were collected and externally identified according to the number of abdominal nerve ganglions: workers (5 ganglions), queens (4 ganglions) and intercastes (4 ganglions). The analysis identified differentially expressed transcripts that were present only in workers, but absent in intercastes and queens, confirming the hypothesis, by demonstrating the environmental effect on the queen genotype that generated phenotype-like workers.

Cytogenetic characterization of Melipona rufiventris Lepeletier 1836 and Melipona mondury Smith 1863 (Hymenoptera, Apidae) by C banding and fluorochromes staining

The stingless bees Melipona rufiventris and M. mondury were analyzed cytogenetically by conventional staining with Giemsa, C-banding and sequential staining with the fluorochromes CMA3/DA/DAPI. Both species presented 2n = 18 and n = 9, except for one colony of M. rufiventris, in which some individuals had 2n = 19 due to the presence of a B chromosome. After Giemsa staining and C-banding the chromosomes appeared very condensed and presented a high heterochromatic content, making it difficult to localize the centromere and therefore to visualize the chromosomes morphology. The constitutive heterochromatin was located in interstitial chromosome regions covering most of the chromosomes extension and consisted mainly of AT, as shown by DAPI staining. The euchromatin was restricted to the chromosome extremities and was GC-rich, as evidenced by CMA3 staining. The B chromosome was CMA3-negative and DAPI-positive, a heterochromatic constitution similar to that of the A genome chromosomes.

Divergência genética em Melipona scutellaris Latreille (Hymenoptera: Apidae) com base em caracteres morfológicos / Genetic divergence in Melipona scutellaris Latreille (Hymenoptera: Apidae) on the basis of morphologic characters

A Melipona scutellaris (Uruçu) é uma espécie endêmica do Nordeste brasileiro, sendo importante não só para a produção de mel e pólen, mas também para a polinização de Fanerógamas. Foram utilizadas técnicas de análise multivariada para comparar populações de M. scutellaris de 8 regiões da Bahia. Foram avaliadas as seguintes características das asas: comprimento e largura das asas anterior e posterior, comprimento da nervura radial, medial e cubital das asas anterior e posterior, comprimento da nervura medial + cubital, da nervura radio sectar + medial – 1º , da nervura radio sectar + medial – 2º , comprimento da nervura anal e comprimento da nervura medial-cubital das asas anteriores e comprimento da nervura radial sectar da asa posterior. Foram necessárias as três primeiras variáveis canônicas para acumular 85% da variação. A análise de agrupamento realizado utilizando distância D2 de Mahalanobis levou a formação de três grupos distintos conforme a altitude, um formado por colônias a 1100m de altitude, um segundo grupo formado por colônias que estão entre 0 e 560m e o terceiro grupo formado por colônias que estão localizadas entre 600 e 964m de altitude. Indicando que provavelmente, as conformações geográficas existentes nestas regiões estejam impedindo que ocorra o fluxo gênico entre essas populações.

The Melipona scutellaris (Uruçu) is a Brazilian northeast endemic bee species, it is important not alone for the production of honey and pollen, but also for the polinization of Fanerógamas. Techniques of multivaried analysis had been used to compare colonies of M. scutellaris from 8 differents regions of the Bahia state, Brazil. The evaluated characteristics had been: length and width of the forewings and posterior wing, length of the radial, medial and cubital venation of the forewings and posterior wings; length of the medial + cubital venation, length of radio sectar + medial - 1º venation, length of the radio sectar + medial - 2º venation, length of the forewings anal venation, length of the medial-cubital venation, all of them in the forewings; and length of the radial sectar venation of the posterior wing. The first three canonic variable had been necessary to accumulate 85% of the variation. The grouping analysis using the Mahalanobis D2 distance shows formation of three distinct groups according to altitude. The first was formed by colonies at 1.100m of altitude, the second was formed by colonies at 0 and 560m of altitude, and the third group was formed by colonies at 600 and 964m of altitude. This results suggest tha the altitude in these regions are hindering the genic flow between these populations.

Molecular identification of species of the Genus Euglossa Latreille (Hymenoptera: Apidae, Euglossini)

Euglossine bees interact with more than 60 plant families of the Neotropical region. The richness and abundance of these bees have been intensively studied in different ecosystems using the methodology of capturing males with chemical baits. Females are poorly known for most of the species and morphological characters for their taxonomic classification have not yet been described. The purpose of this study was to use allozymes and restriction patterns of the mitochondrial regions 16S and Cyt b to identify species of Euglossa Latreille. Bees were collected while visiting Thevetia peruviana (Apocynaceae) flowers in five cities of the state of São Paulo, Brazil. Three Euglossa species were identified among the 305 individuals collected. Euglossa cordata (L.) was the only species found in all cities, while E. securigera Dressler and E. townsendi Cockerell were restricted to two and one cities respectively. EST-3 was a diagnostic marker, whereas ICD, MDH, ME and PGM were informative for species identification when used in combination. Restriction by VspI of the amplified 16S fragment differentiated the three species and showed intraspecific polymorphism for E. cordata and E. securigera. The Cyt b region showed distinctive patterns for E. townsendi but it was not possible to differentiate the other two species. Our results describe potentially useful genetic markers for the identification of Euglossa spp. at the species and group level.

As abelhas euglossíneas interagem com mais de 60 famílias de plantas da Região Neotropical. Sua riqueza e abundância têm sido intensamente estudadas em diferentes ecossistemas utilizando-se a metodologia de captura de machos em iscas-armadilhas. As fêmeas, entretanto, são pouco conhecidas para a maioria das espécies, e caracteres morfológicos que permitam sua identificação taxonômica não têm sido descritos. O propósito deste trabalho foi utilizar alozimas e padrões de restrição das regiões mitocondriais 16S e Cit b para identificar espécies do gênero Euglossa Latreille. As abelhas foram coletadas enquanto visitavam flores de Thevetia peruviana (Apocynaceae) em cinco cidades do estado de São Paulo. Foram identificadas três espécies de Euglossa entre os 305 indivíduos coletados. Euglossa cordata (L.) foi a única espécie presente em todas as cidades, enquanto E. securigera Dressler e E. townsendi Cockerell foram encontradas em duas e uma cidade, respectivamente. EST-3 mostrou-se ser marcador diagnóstico, enquanto ICD, MDH, ME e PGM foram locos informativos para a identificação de espécies quando considerados conjuntamente. A restrição com VspI da região 16S amplificada, além de diferenciar as três espécies, apresentou polimorfismo intraespecífico para E. cordata e E. securigera. A região Cit b apresentou padrões característicos para E. townsendi, mas não permitiu diferenciar as outras duas espécies. Os resultados descrevem marcadores genéticos potencialmente úteis para a identificação de Euglossa spp. ao nível de espécie e grupo de espécies.

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.

Evaluation of the RAPD profiles from different body parts of Euglossa pleosticta Dressler male bees (Hymenoptera: Apidae, Euglossina)

In the current literature, information is scarce on which part of the adult insect body is suitable for isolation of genomic DNA for genetic analysis based on DNA-markers. In this study, we evaluated RAPD profiles generated from total genomic DNA isolated from distinct body parts (head, legs, thorax + wings and abdomen) of 12 males of Euglossa pleosticta Dressler. From the total of bands analyzed, 9.0 percent did not show reproducibility. Percent variations of bands in each body segment were: 1.1 percent (head); 0.4 percent (legs); 0.8 percent (thorax/wings) and 6.7 percent (abdomen). The much higher variation (chi2one sample = 10.27; df = 1; P < 0.01) in the RAPD profiles obtained by using DNA isolated from abdomen of the euglossine males suggests that this body part of adult insects should be avoided in DNA extraction procedures. Conversely, the low variation among the RAPD profiles obtained from amplifications of genomic DNA extracted from head, legs and thorax/wings indicates that all these body parts of male bees are equally useful and secure for using in isolation and amplification procedures of total genomic DNA.

Na literatura atual, são escassas as informações sobre qual a parte do corpo do inseto adulto é mais adequada para a extração de DNA genômico para estudos de análises genéticas baseadas em marcadores de DNA. Neste estudo, foram analisados os perfis de RAPD produzidos a partir da amplificação do DNA genômico extraído de partes distintas do corpo (cabeça, pernas, tórax + asas e abdome) de 12 machos de Euglossa pleosticta Dressler. Do total de bandas analisadas, 9,0 por cento não mostraram repetibilidade. As porcentagens de variação de bandas em relação às diferentes partes do corpo das abelhas foram: 1,1 por cento (cabeça); 0,4 por cento (pernas); 0,8 por cento (tórax/asas) e 6,7 por cento (abdome). A maior variação observada (chi2para uma amostra = 10,27; gl = 1; P < 0,01), nos perfis eletroforéticos de RAPD, produzidos nas amplificações do DNA extraído do abdome de machos euglossíneos sugere que essa parte do corpo de insetos adultos deve ser evitada em procedimentos de extração de DNA. De modo diverso, a baixa variação entre os perfis de RAPD obtidos a partir das amplificações de DNA genômico extraído da cabeça, pernas e tórax/asas das abelhas indica que todas essas partes do corpo de machos euglossíneos são igualmente úteis e confiáveis para serem utilizadas para a extração e a amplificação do DNA genômico.

Alelle number and heterozigosity for microsatellite loci in different stingless bee species (Hymenoptera: Apidae, Meliponini)

In the present study we compare genetic characteristics (allele diversity and observed heterozygosity) of microsatellite loci, from three stingless bee species (Plebeia remota Holmberg, Partamona mulata Moure In Camargo and Partamona helleri Friese), amplified by using heterospecific primers originally designed for Melipona bicolor Lepeletier and Scaptotrigona postica Latreille. We analyzed 360 individuals of P. remota from 72 nests, 58 individuals of P. mulata from 58 nests, and 47 individuals of P. helleri from 47 nests. The three species studied showed low level of polymorphism for the loci amplified with primers derived from M. bicolor. However, for the loci amplified with primers derived from S. postica, only P. remota presented low level of polymorphism.

No presente trabalho compararam-se as características de locos de microssatélite, como diversidade alélica e taxa de heterozigose observada, de três espécies de abelhas sem ferrão (Plebeia remota Holmberg, Partamona mulata Moure In Camargo e Partamona helleri Friese), amplificados com oligonucleotídeos heteroespecíficos originalmente desenhados para Melipona bicolor Lepeletier e Scaptotrigona postica Latreille. Foram analisados 360 indivíduos de P. remota de 72 ninhos, 58 indivíduos de P. mulata de 58 ninhos e 47 indivíduos de P. helleri de 47 ninhos. As três espécies apresentaram baixo nível de polimorfismo para locos amplificados com oligonucleotídeos derivados de Melipona bicolor. Entretanto, para os locos amplificados com oligonucleotídeos derivados de S. postica, somente P. remota apresentou baixo nível de polimorfismo.

Genetic similarity among male bees of Euglossa truncata Rebêlo & Moure (Hymenoptera: Apidae) revealed by RAPD markers

The genetic RAPD (random amplified polymorphic DNA) markers have been used successfully in taxonomical studies of several groups of organisms. In the present study these molecular markers were used to analyze the genetic similarity among eighteen males of Euglossa truncata Rebêlo & Moure exhibiting variations in two morphological characters (colour of the antennal scape and metaepisternal hairs) which are frequently used to identify this species of euglossine bee. The twelve primers used in the RAPD analysis amplified 127 loci, of which 40 (31.5 percent) were polymorphic, showing some variation among the individuals. The coefficients of genetic similarity among the individuals ranged from 0.79 to 0.95, indicating a rather high genetic similarity among the 18 male bees studied. No RAPD band was specific to any morphological character analyzed. The results indicate that all bees analyzed belong to the same species. The high genetic similarity among the eighteen euglossine males studied indicates that the variations observed in the morphological characters are not in disagreement with the identification of this species of Euglossina and these characters can vary among males of E. truncata.

Os marcadores genéticos RAPD (DNA polimórfico amplificado ao acaso) têm sido empregados com sucesso em estudos taxonômicos de diversos grupos de organismos. No presente trabalho esses marcadores moleculares foram utilizados para analisar a similaridade genética entre dezoito machos de Euglossa truncata Rebêlo & Moure apresentando variações em dois caracteres morfológicos (coloração do escapo antenal e da pilosidade dos tufos metaepisternais), os quais normalmente são utilizados na identificação dessa espécie de abelha Euglossina. Os 12 primers utilizados nas análises produziram 127 locos de RAPD, dos quais 40 (31,5 por cento) foram polimórficos, revelando alguma variação genética entre os indivíduos analisados. Os coeficientes de similaridade genética entre os indivíduos variaram de 0,79 a 0,95, indicando alta similaridade entre os 18 machos analisados. Nenhuma banda de RAPD mostrou-se específica para os caracteres morfológicos considerados. Os resultados obtidos indicam que todos os machos analisados pertencem à mesma espécie euglossina. A alta similaridade genética entre os dezoito machos eulossíneos indica que as variações observadas nos caracteres morfológicos destes não estão em discordância com a identificação dessa espécie de Euglossina, e que tais caracteres podem variar entre os machos de E. truncata.

Differentially displayed expressed sequence tags in Melipona scutellaris (Hymenoptera, Apidae, Meliponini) development

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.

A comparative analysis of highly conserved sex-determining genes between Apis mellifera and Drosophila melanogaster

A comparison of the most conserved sex-determining genes between the fruit fly, Drosophila melanogaster, and the honey bee, Apis mellifera, was performed with bioinformatics tools developed for computational molecular biology. An initial set of protein sequences already described in the fruit fly as participants of the sex-determining cascade was retrieved from the Gene Ontology database (http://www.geneontology.org/) and aligned against a database of protein sequences predicted from the honey bee genome. The doublesex (dsx) gene is considered one of the most conserved sex-determining genes among metazoans, and a male-specific partial cDNA of putative A. mellifera dsx gene (Amdsx) was identified experimentally. The theoretical predictions were developed in the context of sequence similarity. Experimental evidence indicates that dsx is present in embryos and larvae, and that it encodes a transcription factor widely conserved in metazoans, containing a DM DNA-binding domain implicated in the regulation of the expression of genes involved in sexual phenotype formation.