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Dive into the research topics where Angel Roberto Barchuk is active.

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Featured researches published by Angel Roberto Barchuk.


FEBS Letters | 2005

Vitellogenin regulates hormonal dynamics in the worker caste of a eusocial insect

Karina R. Guidugli; Adriana Mendes do Nascimento; Gro V. Amdam; Angel Roberto Barchuk; Stig W. Omholt; Zilá Luz Paulino Simões; Klaus Hartfelder

Functionally sterile honey bee workers synthesize the yolk protein vitellogenin while performing nest tasks. The subsequent shift to foraging is linked to a reduced vitellogenin and an increased juvenile hormone (JH) titer. JH is a principal controller of vitellogenin expression and behavioral development. Yet, we show here that silencing of vitellogenin expression causes a significant increase in JH titer and its putative receptor. Mathematically, the increase corresponds to a dynamic dose–response. This role of vitellogenin in the tuning of the endocrine system is uncommon and may elucidate how an ancestral pathway of fertility regulation has been remodeled into a novel circuit controlling social behavior.


Journal of Insect Science | 2002

Effects of juvenile hormone and ecdysone on the timing of vitellogenin appearance in hemolymph of queen and worker pupae of Apis mellifera

Angel Roberto Barchuk; Márcia Maria Gentile Bitondi; Zilá Luz Paulino Simões

Abstract The caste-specific regulation of vitellogenin synthesis in the honeybee represents a problem with many yet unresolved details. We carried out experiments to determine when levels of vitellogenin are first detected in hemolymph of female castes of Apis mellifera, and whether juvenile hormone and ecdysteroids modulate this process. Vitellogenin levels were measured in hemolymph using immunological techniques. We show that in both castes the appearance of vitellogenin in the hemolymph occurs during the pupal period, but the timing was different in the queen and worker. Vitellogenin appears in queens during an early phase of cuticle pigmentation approximately 60h before eclosion, while in workers the appearance of vitellogenin is more delayed, initiating in the pharate adult stage, approximately 10h before eclosion. The timing of vitellogenin appearance in both castes coincides with a slight increase in endogenous levels of juvenile hormone that occurs at the end of pupal development. The correlation between these events was corroborated by topical application of juvenile hormone. Exogenous juvenile hormone advanced the timing of vitellogenin appearance in both castes, but caste-specific differences in timing were maintained. Injection of actinomycin D prevented the response to juvenile hormone. In contrast, queen and worker pupae that were treated with ecdysone showed a delay in the appearance of vitellogenin. These data suggest that queens and workers share a common control mechanism for the timing of vitellogenin synthesis, involving an increase in juvenile hormone titers in the presence of low levels of ecdysteroids.


Insect Biochemistry and Molecular Biology | 2003

The vitellogenin of the honey bee, Apis mellifera : structural analysis of the cDNA and expression studies

Maria-Dolors Piulachs; Karina R. Guidugli; Angel Roberto Barchuk; J. Cruz; Zilá Luz Paulino Simões; Xavier Bellés

The cDNA of Apis mellifera vitellogenin was cloned and sequenced. It is 5440 bp long and contains an ORF of 1770 amino acids (including a putative signal peptide of 16 residues). The deduced amino acid sequence shows significant similarity with other hymenopteran vitellogenins (58% with Pimpla nipponica and 54% with Athalia rosae). The alignment with 19 insect vitellogenins shows a high number of conserved motifs; for example, close to the C-terminus there is a GL/ICG motif followed by nine cysteines, as occurs in all hymenopteran species, and, as in other insect vitellogenins, a DGXR motif is located 18 residues upstream the GL/ICG motif. Phylogenetic analysis of vitellogenin sequences available in insects gave a tree that is congruent with the currently accepted insect phylogenetic schemes. Using two fragments of the vitellogenin cDNA as probes, we analyzed by Northern blot the sex- and caste-specific patterns of vitellogenin expression in pupae and adults of A. mellifera. In queens, vitellogenin mRNA was first detected in mid-late pupal stage, whereas in workers it was first detected in late pupal stage. Vitellogenin mRNA was also observed in drones, although it was first detected not in pupae but in freshly molted adults.


Insect Molecular Biology | 2004

Apis mellifera ultraspiracle: cDNA sequence and rapid up-regulation by juvenile hormone

Angel Roberto Barchuk; Ryszard Maleszka; Zilá Luz Paulino Simões

Two hormones, 20‐hydroxyecdysone (20E) and juvenile hormone (JH) are key regulators of insect development including the differentiation of the alternative caste phenotypes of social insects. In addition, JH plays a different role in adult honey bees, acting as a ‘behavioural pacemaker’. The functional receptor for 20E is a heterodimer consisting of the ecdysone receptor and ultraspiracle (USP) whereas the identity of the JH receptor remains unknown. We have cloned and sequenced a cDNA encoding Apis mellifera ultraspiracle (AMUSP) and examined its responses to JH. A rapid, but transient up‐regulation of the AMUSP messenger is observed in the fat bodies of both queens and workers. AMusp appears to be a single copy gene that produces two transcripts (∼4 and ∼5 kb) that are differentially expressed in the animals body. The predicted AMUSP protein shows greater sequence similarity to its orthologues from the vertebrate–crab–tick–locust group than to the dipteran–lepidopteran group. These characteristics and the rapid up‐regulation by JH suggest that some of the USP functions in the honey bee may depend on ligand binding.


Nature Communications | 2014

Neuroligin-associated microRNA-932 targets actin and regulates memory in the honeybee

Alexandre S. Cristino; Angel Roberto Barchuk; Flávia Cristina de Paula Freitas; Ramesh K. Narayanan; Stephanie D. Biergans; Zhengyang Zhao; Zilá Luz Paulino Simões; Judith Reinhard; Charles Claudianos

Increasing evidence suggests small non-coding RNAs (ncRNAs) such as microRNAs (miRNAs) control levels of mRNA expression during experience-related remodelling of the brain. Here we use an associative olfactory learning paradigm in the honeybee Apis mellifera to examine gene expression changes in the brain during memory formation. Brain transcriptome analysis reveals a general downregulation of protein-coding genes, including asparagine synthetase and actin, and upregulation of ncRNAs. miRNA-mRNA network predictions together with PCR validation suggest miRNAs including miR-210 and miR-932 target the downregulated protein-coding genes. Feeding cholesterol-conjugated antisense RNA to bees results in the inhibition of miR-210 and of miR-932. Loss of miR-932 impairs long-term memory formation, but not memory acquisition. Functional analyses show that miR-932 interacts with Act5C, providing evidence for direct regulation of actin expression by an miRNA. An activity-dependent increase in miR-932 expression may therefore control actin-related plasticity mechanisms and affect memory formation in the brain.


Journal of Insect Physiology | 2008

Downregulation of ultraspiracle gene expression delays pupal development in honeybees

Angel Roberto Barchuk; Vera Lúcia Castelo Figueiredo; Zilá Luz Paulino Simões

Ecdysteroids regulate many aspects of insect physiology after binding to a heterodimer composed of the nuclear hormone receptor proteins ecdysone receptor (EcR) and ultraspiracle (Usp). Several lines of evidence have suggested that the latter also plays important roles in mediating the action of juvenile hormone (JH) and, thus, integrates signaling by the two morphogenetic hormones. By using an RNAi approach, we show here that Usp participates in the mechanism that regulates the progression of pupal development in Apis mellifera, as indicated by the observed pupal developmental delay in usp knocked-down bees. Knock-down experiments also suggest that the expression of regulatory genes such as ftz transcription factor 1 (ftz-f1) and juvenile hormone esterase (jhe) depend on Usp. Vitellogenin (vg), the gene coding the main yolk protein in honeybees, does not seem to be under Usp regulation, thus suggesting that the previously observed induction of vg expression by JH during the last stages of pupal development is mediated by yet unknown transcription factor complexes.


Frontiers in Genetics | 2014

Developmental regulation of ecdysone receptor (EcR) and EcR-controlled gene expression during pharate-adult development of honeybees (Apis mellifera).

Tathyana Rachel Palo Mello; Aline Carolina Aleixo; Daniel G. Pinheiro; Francis Morais Franco Nunes; Márcia Maria Gentile Bitondi; Klaus Hartfelder; Angel Roberto Barchuk; Zilá Luz Paulino Simões

Major developmental transitions in multicellular organisms are driven by steroid hormones. In insects, these, together with juvenile hormone (JH), control development, metamorphosis, reproduction and aging, and are also suggested to play an important role in caste differentiation of social insects. Here, we aimed to determine how EcR transcription and ecdysteroid titers are related during honeybee postembryonic development and what may actually be the role of EcR in caste development of this social insect. In addition, we expected that knocking-down EcR gene expression would give us information on the participation of the respective protein in regulating downstream targets of EcR. We found that in Apis mellifera females, EcR-A is the predominantly expressed variant in postembryonic development, while EcR-B transcript levels are higher in embryos, indicating an early developmental switch in EcR function. During larval and pupal stages, EcR-B expression levels are very low, while EcR-A transcripts are more variable and abundant in workers compared to queens. Strikingly, these transcript levels are opposite to the ecdysteroid titer profile. 20-hydroxyecdysone (20E) application experiments revealed that low 20E levels induce EcR expression during development, whereas high ecdysteroid titers seem to be repressive. By means of RNAi-mediated knockdown (KD) of both EcR transcript variants we detected the differential expression of 234 poly-A+ transcripts encoding genes such as CYPs, MRJPs and certain hormone response genes (Kr-h1 and ftz-f1). EcR-KD also promoted the differential expression of 70 miRNAs, including highly conserved ones (e.g., miR-133 and miR-375), as well honeybee-specific ones (e.g., miR-3745 and miR-3761). Our results put in evidence a broad spectrum of EcR-controlled gene expression during postembryonic development of honeybees, revealing new facets of EcR biology in this social insect.


BMC Genomics | 2013

Genes involved in thoracic exoskeleton formation during the pupal-to-adult molt in a social insect model, Apis mellifera

Michelle Soares; Angel Roberto Barchuk; Ana Carolina Quirino Simões; Alexandre S. Cristino; Flávia Cristina de Paula Freitas; Luísa Lange Canhos; Márcia Maria Gentile Bitondi

BackgroundThe insect exoskeleton provides shape, waterproofing, and locomotion via attached somatic muscles. The exoskeleton is renewed during molting, a process regulated by ecdysteroid hormones. The holometabolous pupa transforms into an adult during the imaginal molt, when the epidermis synthe3sizes the definitive exoskeleton that then differentiates progressively. An important issue in insect development concerns how the exoskeletal regions are constructed to provide their morphological, physiological and mechanical functions. We used whole-genome oligonucleotide microarrays to screen for genes involved in exoskeletal formation in the honeybee thoracic dorsum. Our analysis included three sampling times during the pupal-to-adult molt, i.e., before, during and after the ecdysteroid-induced apolysis that triggers synthesis of the adult exoskeleton.ResultsGene ontology annotation based on orthologous relationships with Drosophila melanogaster genes placed the honeybee differentially expressed genes (DEGs) into distinct categories of Biological Process and Molecular Function, depending on developmental time, revealing the functional elements required for adult exoskeleton formation. Of the 1,253 unique DEGs, 547 were upregulated in the thoracic dorsum after apolysis, suggesting induction by the ecdysteroid pulse. The upregulated gene set included 20 of the 47 cuticular protein (CP) genes that were previously identified in the honeybee genome, and three novel putative CP genes that do not belong to a known CP family. In situ hybridization showed that two of the novel genes were abundantly expressed in the epidermis during adult exoskeleton formation, strongly implicating them as genuine CP genes. Conserved sequence motifs identified the CP genes as members of the CPR, Tweedle, Apidermin, CPF, CPLCP1 and Analogous-to-Peritrophins families. Furthermore, 28 of the 36 muscle-related DEGs were upregulated during the de novo formation of striated fibers attached to the exoskeleton. A search for cis-regulatory motifs in the 5′-untranslated region of the DEGs revealed potential binding sites for known transcription factors. Construction of a regulatory network showed that various upregulated CP- and muscle-related genes (15 and 21 genes, respectively) share common elements, suggesting co-regulation during thoracic exoskeleton formation.ConclusionsThese findings help reveal molecular aspects of rigid thoracic exoskeleton formation during the ecdysteroid-coordinated pupal-to-adult molt in the honeybee.


Insect Molecular Biology | 2010

Organization, evolution and transcriptional profile of hexamerin genes of the parasitic wasp Nasonia vitripennis (Hymenoptera: Pteromalidae).

Alexandre S. Cristino; Francis M. F. Nunes; Angel Roberto Barchuk; V. M. Aguiar-Coelho; Zilá Luz Paulino Simões; Márcia Maria Gentile Bitondi

Hexamerins and prophenoloxidases (PPOs) proteins are members of the arthropod‐haemocyanin superfamily. In contrast to haemocyanin and PPO, hexamerins do not bind oxygen, but mainly play a role as storage proteins that supply amino acids for insect metamorphosis. We identified seven genes encoding hexamerins, three encoding PPOs, and one hexamerin pseudogene in the genome of the parasitoid wasp Nasonia vitripennis. A phylogenetic analysis of hexamerins and PPOs from this wasp and related proteins from other insect orders suggests an essentially order‐specific radiation of hexamerins. Temporal and spatial transcriptional profiles of N. vitripennis hexamerins suggest that they have physiological functions other than metamorphosis, which are arguably coupled with its lifestyle.


PLOS ONE | 2013

Nutritionally driven differential gene expression leads to heterochronic brain development in honeybee castes.

Livia Moda; Joseana Vieira; Anna Cláudia Guimarães Freire; Vanessa Bonatti; Ana Durvalina Bomtorin; Angel Roberto Barchuk; Zilá Luz Paulino Simões

The differential feeding regimes experienced by the queen and worker larvae of the honeybee Apis mellifera shape a complex endocrine response cascade that ultimately gives rise to differences in brain morphologies. Brain development analyzed at the morphological level from the third (L3) through fifth (L5) larval instars revealed an asynchrony between queens and workers. In the feeding phase of the last larval instar (L5F), two well-formed structures, pedunculi and calyces, are identifiable in the mushroom bodies of queens, both of which are not present in workers until a later phase (spinning phase, L5S). Genome-wide expression analyses and normalized transcript expression experiments monitoring specific genes revealed that this differential brain development starts earlier, during L3. Analyzing brains from L3 through L5S1 larvae, we identified 21 genes with caste-specific transcription patterns (e.g., APC-4, GlcAT-P, fax, kr-h1 and shot), which encode proteins that are potentially involved in the development of brain tissues through controlling the cell proliferation rate (APC4, kr-h1) and fasciculation (GlcAT-P, fax, and shot). Shot, whose expression is known to be required for axon extension and cell proliferation, was found to be transcribed at significantly higher levels in L4 queens compared with worker larvae. Moreover, the protein encoded by this gene was immunolocalized to the cytoplasm of cells near the antennal lobe neuropiles and proximal to the Kenyon cells in the brains of L4 queens. In conclusion, during the larval period, the brains of queens are larger and develop more rapidly than workers’ brains, which represents a developmental heterochrony reflecting the effect of the differential feeding regime of the two castes on nervous system development. Furthermore, this differential development is characterized by caste-specific transcriptional profiles of a set of genes, thus pointing to a link between differential nutrition and differential neurogenesis via genes that control cell proliferation and fasciculation.

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Alexandre S. Cristino

International Federation of Sport Climbing

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Joseana Vieira

Universidade Federal de Alfenas

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Livia Moda

University of São Paulo

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Francis Morais Franco Nunes

Federal University of São Carlos

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