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Se presenta el primer reporte de la abeja colectora de óleo Centris (Odontoxys) melanochlaena Smith, 1874 en Nicaragua. Esta especie se distribuye en varios países de Centroamérica y México, siendo este el primer reporte en el occidente de Nicaragua. Este registro contribuye al conocimiento del rango de distribución de esta especie, así como también incrementa la lista de especies de abejas nativas de Nicaragua.

The first report of the oil-collecting bee Centris (Odontoxys) melanochlaena Smith, 1874 in Nicaragua is presented. This species occurs in several Central American countries and Mexico, being this the first record from western Nicaragua. This record contributes to the knowledge of the distribution range of this species, as well as increases the list of native bees occurring in Nicaragua.

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Megachile amparo (González, Revista Colombiana De Entomología 32(1):93-96, 2006) is the only high Andean leaf-cutter bee reported in Colombia and is possibly endemic to the Colombian Andes. Although it is frequently observed, even in urban areas, its biology and ecology remain unknown. The present study aimed to describe detailed aspects of its bionomy. Trap-nests were installed on the Campus of the Nueva Granada University (Cajicá, Colombia) from June/2018 to March/2020. The trap-nests were wooden blocks (25 × 15 × 14 cm) with 30 cavities of Ø = 1 cm and different lengths (50 mm, 75 mm, and 100 mm) lined with waxed paper straws. During the observations, an increasing number of trap-nests were installed, increasing from 250 to 720 cavities. The trap-nests were monitored three times a week, recording both the date the start and end building by female. Most of the nest were maintained in the field to estimate the sex ratio, cell survival, and total development time under natural conditions. Thirty-two nests were removed at different times of the observation period to establish number of cells per nest, and cells built per female per day. We incubated 20 cells from different nests at 18 °C, 22 °C, 26 °C, and 32 °C to estimate the base temperature, thermal constant k (developmental time in degree days), and cell survival. Young cells of different positions were dissected and weighed to characterize food provision and brood cells. Computerized tomography-CT scans were performed in 30 brood cells to determine if diapause occurred during prepupal stage. Females nested 7- and 10-cm-long cavities and the number of cells per nest varied with cavity length. The brood cells had a length of 1.23 ± 0.12 cm and a diameter of 0.92 ± 0.05 cm. The female spends 1.17 ± 0.29 days to build a brood cell. Food provision varied according to the position of the brood cell in the nest. The adults of M. amparo present a marked seasonality being more active during dry months. Base temperature and thermal constant k were different for males and females. The sex ratio is female biased (1.9:1), and cell survival in the field was 89% with no cleptoparasites or predators recorded.

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In this paper are presented notes on the primary types of some species of the oil-collecting bees of the genus Centris Fabricius, 1804 described by Alpheus Packard, Arturo Roig-Alsina, Charles Michener, Flamínio Ruiz, Haroldo Toro, James Crawford, Jesus Santiago Moure, Philip Timberlake, and Roy Snelling. Information on the type status, type locality and depository are provided.(AU)

Neste artigo são apresentadas notas sobre os tipos primários de algumas espécies de abelhas coletoras de óleo do gênero Centris Fabricius, 1804 descritas por Alpheus Packard, Arturo Roig-Alsina, Charles Michener, Flamínio Ruiz, Haroldo Toro, James Crawford, Jesus Santiago Moure, Philip Timberlake e Roy Snelling. São fornecidas informações sobre o status dos tipos, localidade tipo e depositário.(AU)

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ABSTRACT One nest of Megachile (Moureapis) benigna Mitchell, 1930 (Hymenoptera: Megachilidae) was collected using trap-nests in a forest fragment (Atlantic Forest biome) into an urban matrix in Rio de Janeiro, Brazil, in October/2017. The nest architecture and larval food are presented providing initial data for management and conservation of this species in cities.

RESUMO Um ninho de Megachile (Moureapis) benigna Mitchell, 1930 (Hymenoptera: Megachilidae) foi coletado usando ninhos-armadilha em um fragmento de floresta (bioma Mata Atlântica) em uma área urbana no Rio de Janeiro, Brasil, em outubro/2017. A arquitetura do ninho e o alimento larval são apresentados fornecendo dados iniciais para o manejo e conservação desta espécie nas cidades.

RESUMO

One nest of Megachile (Moureapis) benigna Mitchell, 1930 (Hymenoptera: Megachilidae) was collected using trap-nests in a forest fragment (Atlantic Forest biome) into an urban matrix in Rio de Janeiro, Brazil, in October/2017. The nest architecture and larval food are presented providing initial data for management and conservation of this species in cities.

Um ninho de Megachile (Moureapis) benigna Mitchell, 1930 (Hymenoptera: Megachilidae) foi coletado usando ninhos-armadilha em um fragmento de floresta (bioma Mata Atlântica) em uma área urbana no Rio de Janeiro, Brasil, em outubro/2017. A arquitetura do ninho e o alimento larval são apresentados fornecendo dados iniciais para o manejo e conservação desta espécie nas cidades.

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Olfactory cues constitute one of the most important plant-pollinator communication channels. Specific chemical components can be associated with specific pollinator functional groups due to pollinator-mediated selection on flower volatile (FV) emission. Here, we used multivariate analyses of FV data to detect an association between FVs and the worldwide distributed pollinator group of the carpenter bees (Xylocopa spp.). We compiled FVs of 29 plant species: 9 pollinated by carpenter bees, 20 pollinated by other bee pollinator functional groups. We tested whether FV emission differed between these groups. To rule out any phylogenetic bias in our dataset, we tested FV emission for phylogenetic signal. Finally, using field assays, we tested the attractive function of two FVs found to be associated with carpenter bees. We found no significant multivariate difference between the two plant groups FVs. However, seven FVs (five apocarotenoid terpenoids, one long-chain alkane and one benzenoid) were significantly associated with carpenter bee pollination, thus being "predictor" compounds of pollination by this pollinator functional group. From those, ß-ionone and (E)-methyl cinnamate presented the highest indicator values and had their behavioural function assessed in field assays. Phylogenetic signal for FVs emission was weak, suggesting that their emission could result from pollinator-mediated selection. In field assays, the apocarotenoid ß-ionone attracted carpenter bees, but also bees from other functional groups. The benzenoid (E)-methyl cinnamate did not attract significant numbers of pollinators. Thus, ß-ionone functions as a non-specific bee attractant, while apocarotenoid FVs emerge as consistent indicators of pollination by large food-foraging bees among bee-pollinated flowers.

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Nests of the oil-collecting bee Epicharis (Hoplepicharis) fasciata Lepeletier & Serville, 1828 were studied at the Jardim Botânico of Rio de Janeiro, Brazil. The females constructed their nests in an area of 609 m2 of mostly sandy flat soil. The nest architecture was relatively simple, with a main tunnel of approximately 30 cm in depth with one or two lateral tunnels ending in a single brood cell. Adult activity lasted approximately 45 days. The females dug the tunnels, constructed the brood cells, collected provisions and laid the eggs in approximately two days. Diapause occurred in the post defecating larval stage, and there was no cocoon. Nest architecture and the morphology of the brood cells are described and illustrated.

Ninhos da abelha coletora de óleo Epicharis (Hoplepicharis) fasciata Lepeletier & Serville, 1828 foram estudados no Jardim Botânico do Rio de Janeiro, Brasil. As fêmeas construíram seus ninhos em uma área de 609 m2 de solo plano principalmente arenoso. A arquitetura do ninho é relativamente simples, com um túnel principal de aproximadamente 30 cm de profundidade, com um ou dois túneis laterais terminando em uma única célula de cria. A atividade dos adultos se estendeu por cerca de 45 dias. As fêmeas cavam os túneis, constroem as células de cria, coletam as provisões e depositam os ovos em aproximadamente dois dias. A diapausa ocorreu no estágio de larva pós-defecante e não houve casulo. A arquitetura dos ninhos e a morfologia das células de cria são descritas e ilustradas.

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ABSTRACT Nests of the oil-collecting bee Epicharis (Hoplepicharis) fasciata Lepeletier & Serville, 1828 were studied at the Jardim Botânico of Rio de Janeiro, Brazil. The females constructed their nests in an area of 609 m2 of mostly sandy flat soil. The nest architecture was relatively simple, with a main tunnel of approximately 30 cm in depth with one or two lateral tunnels ending in a single brood cell. Adult activity lasted approximately 45 days. The females dug the tunnels, constructed the brood cells, collected provisions and laid the eggs in approximately two days. Diapause occurred in the post defecating larval stage, and there was no cocoon. Nest architecture and the morphology of the brood cells are described and illustrated.

RESUMO Ninhos da abelha coletora de óleo Epicharis (Hoplepicharis) fasciata Lepeletier & Serville, 1828 foram estudados no Jardim Botânico do Rio de Janeiro, Brasil. As fêmeas construíram seus ninhos em uma área de 609 m2 de solo plano principalmente arenoso. A arquitetura do ninho é relativamente simples, com um túnel principal de aproximadamente 30 cm de profundidade, com um ou dois túneis laterais terminando em uma única célula de cria. A atividade dos adultos se estendeu por cerca de 45 dias. As fêmeas cavam os túneis, constroem as células de cria, coletam as provisões e depositam os ovos em aproximadamente dois dias. A diapausa ocorreu no estágio de larva pós-defecante e não houve casulo. A arquitetura dos ninhos e a morfologia das células de cria são descritas e ilustradas.

RESUMO

Nests of the oil-collecting bee Epicharis (Hoplepicharis) fasciata Lepeletier & Serville, 1828 were studied at the Jardim Botânico of Rio de Janeiro, Brazil. The females constructed their nests in an area of 609 m2 of mostly sandy flat soil. The nest architecture was relatively simple, with a main tunnel of approximately 30 cm in depth with one or two lateral tunnels ending in a single brood cell. Adult activity lasted approximately 45 days. The females dug the tunnels, constructed the brood cells, collected provisions and laid the eggs in approximately two days. Diapause occurred in the post defecating larval stage, and there was no cocoon. Nest architecture and the morphology of the brood cells are described and illustrated.(AU)

Ninhos da abelha coletora de óleo Epicharis (Hoplepicharis) fasciata Lepeletier & Serville, 1828 foram estudados no Jardim Botânico do Rio de Janeiro, Brasil. As fêmeas construíram seus ninhos em uma área de 609 m2 de solo plano principalmente arenoso. A arquitetura do ninho é relativamente simples, com um túnel principal de aproximadamente 30 cm de profundidade, com um ou dois túneis laterais terminando em uma única célula de cria. A atividade dos adultos se estendeu por cerca de 45 dias. As fêmeas cavam os túneis, constroem as células de cria, coletam as provisões e depositam os ovos em aproximadamente dois dias. A diapausa ocorreu no estágio de larva pós-defecante e não houve casulo. A arquitetura dos ninhos e a morfologia das células de cria são descritas e ilustradas.(AU)

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Abstract Megachile Latreille is a conspicuous genus of solitary bees distributed worldwide. However, the biology of tropical species is still little known. We present data on biology of Megachile brasiliensis Data Torre, Megachile sejuncta Cockerell and Megachile stilbonotaspis Moure found in two remnants of eastern Amazonian forest in northeastern Brazil. The study was conducted using the trap-nest methodology in two different areas during four periods. We collected a total of 24 nests of M. brasiliensis, 26 of M. sejuncta and 28 of M. stilbonotaspis. The differential abundance of collected nests may reflect the population size in each sampled place. The nesting activity was concentrated mainly between July and January and species presented a multivoltine pattern, except for M. sejuncta, which was partly univoltine. Assessed pollen use showed a predominant use of Attalea sp. (Arecaceae) and, for M. stilbonotaspis, Tylesia sp. and Lepidaploa sp. (Asteraceae). Babassu is a very common palm in the studied areas and the studied species seem to have a strong link with it. We also reported change of pollen use by M. sejuncta, probably due to competition with M. brasiliensis, which may have influenced the biased sex ratio observed in M. sejuncta toward males. Parasites reported here were also recorded for other Megachile species, such as Coelioxys, Brachymeria, Meloidae and Pyralidae species. Mites were observed in association with M. stilbonotaspis. The data presented here set up a background that encourages new studies on the ecology of these three Amazonian species, providing tools for proper biodiversity management and conservation.

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BACKGROUND: Among the hymenopteran insect venoms, those from social wasps and bees - such as honeybee, hornets and paper wasps - have been well documented. Their venoms are composed of a number of peptides and proteins and used for defending their nests and themselves from predators. In contrast, the venoms of solitary wasps and bees have not been the object of further research. In case of solitary bees, only major peptide components in a few venoms have been addressed. Therefore, the aim of the present study was to explore the peptide component profile of the venom from the solitary bee Xylocopa appendiculata circumvolans by peptidomic analysis with using LC-MS. METHODS: A reverse-phase HPLC connected to ESI-OrbiTrap MS was used for LC-MS. On-line mass fingerprinting was made from TIC, and data-dependent tandem mass spectrometry gave MSMS spectra. A major peptide component was isolated by reverse-phase HPLC by conventional way, and its sequence was determined by Edman degradation, which was finally corroborated by solid phase synthesis. Using the synthetic specimen, biological activities (antimicrobial activity, mast cell devaluation, hemolysis, leishmanicidal activity) and pore formation in artificial lipid bilayer were evaluated. RESULTS: On-line mass fingerprinting revealed that the crude venom contained 124 components. MS/MS analysis gave 75 full sequences of the peptide components. Most of these are related to the major and novel peptide, xylopin. Its sequence, GFVALLKKLPLILKHLH-NH2, has characteristic features of linear cationic α-helical peptides; rich in hydrophobic and basic amino acids with no disulfide bond, and accordingly, it can be predicted to adopt an amphipathic α-helix secondary structure. In biological evaluation, xylopin exhibited broad-spectrum antimicrobial activity, and moderate mast cell degranulation and leishmanicidal activities, but showed virtually no hemolytic activity. Additionally, the peptide was able to incorporate pores in artificial lipid bilayers of azolectin, confirming the mechanism of the cytolytic activity by pore formation in biological membranes. CONCLUSIONS: LC-ESI-MS and MS/MS analysis of the crude venom extract from a solitary bee Xylocopa appendiculata circumvolans revealed that the component profile of this venom mostly consisted of small peptides. The major peptide components, xylopin and xylopinin, were purified and characterized in a conventional manner. Their chemical and biological characteristics, belonging to linear cationic α-helical peptides, are similar to the known solitary bee venom peptides, melectin and osmin. Pore formation in artificial lipid bilayers was demonstrated for the first time with a solitary bee peptide.

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BACKGROUND: Mass spectrometry-guided venom peptide profiling is a powerful tool to explore novel substances from venomous animals in a highly sensitive manner. In this study, this peptide profiling approach is successfully applied to explore the venom peptides of a Japanese solitary carpenter bee, Xylocopa appendiculata (Hymenoptera: Apoidea: Apidae: Anthophila: Xylocopinae: Xylocopini). Although interesting biological effects of the crude venom of carpenter bees have been reported, the structure and biological function of the venom peptides have not been elucidated yet. METHODS: The venom peptide profiling of the crude venom of X. appendiculata was performed by matrix-assisted laser desorption/ionization-time of flight mass spectroscopy. The venom was purified by a reverse-phase HPLC. The purified peptides were subjected to the Edman degradation, MS/MS analysis, and/or molecular cloning methods for peptide sequencing. Biological and functional characterization was performed by circular dichroism analysis, liposome leakage assay, and antimicrobial, histamine releasing and hemolytic activity tests. RESULTS: Three novel peptides with m/z 16508, 1939.3, and 1900.3 were isolated from the venom of X. appendiculata. The peptide with m/z 16508 was characterized as a secretory phospholipase A2 (PLA2) homolog in which the characteristic cysteine residues as well as the active site residues found in bee PLA2s are highly conserved. Two novel peptides with m/z 1939.3 and m/z 1900.3 were named as Xac-1 and Xac-2, respectively. These peptides are found to be amphiphilic and displayed antimicrobial and hemolytic activities. The potency was almost the same as that of mastoparan isolated from the wasp venom. CONCLUSION: We found three novel biologically active peptides in the venom of X. appendiculata and analyzed their molecular functions, and compared their sequential homology to discuss their molecular diversity. Highly sensitive mass analysis plays an important role in this study.

RESUMO

Background: Among the hymenopteran insect venoms, those from social wasps and bees - such as honeybee, hornets and paper wasps - have been well documented. Their venoms are composed of a number of peptides and proteins and used for defending their nests and themselves from predators. In contrast, the venoms of solitary wasps and bees have not been the object of further research. In case of solitary bees, only major peptide components in a few venoms have been addressed. Therefore, the aim of the present study was to explore the peptide component profile of the venom from the solitary bee Xylocopa appendiculata circumvolans by peptidomic analysis with using LC-MS. Methods: A reverse-phase HPLC connected to ESI-OrbiTrap MS was used for LC-MS. On-line mass fingerprinting was made from TIC, and data-dependent tandem mass spectrometry gave MSMS spectra. A major peptide component was isolated by reverse-phase HPLC by conventional way, and its sequence was determined by Edman degradation, which was finally corroborated by solid phase synthesis. Using the synthetic specimen, biological activities (antimicrobial activity, mast cell devaluation, hemolysis, leishmanicidal activity) and pore formation in artificial lipid bilayer were evaluated. Results: On-line mass fingerprinting revealed that the crude venom contained 124 components. MS/MS analysis gave 75 full sequences of the peptide components. Most of these are related to the major and novel peptide, xylopin. Its sequence, GFVALLKKLPLILKHLH-NH2, has characteristic features of linear cationic α-helical peptides; rich in hydrophobic and basic amino acids with no disulfide bond, and accordingly, it can be predicted to adopt an amphipathic α-helix secondary structure. In biological evaluation, xylopin exhibited broad-spectrum antimicrobial activity, and moderate mast cell degranulation and leishmanicidal activities, but showed virtually no hemolytic activity. Additionally, the peptide was able to incorporate pores in artificial lipid bilayers of azolectin, confirming the mechanism of the cytolytic activity by pore formation in biological membranes. Conclusions: LC-ESI-MS and MS/MS analysis of the crude venom extract from a solitary bee Xylocopa appendiculata circumvolans revealed that the component profile of this venom mostly consisted of small peptides. The major peptide components, xylopin and xylopinin, were purified and characterized in a conventional manner. Their chemical and biological characteristics, belonging to linear cationic α-helical peptides, are similar to the known solitary bee venom peptides, melectin and osmin. Pore formation in artificial lipid bilayers was demonstrated for the first time with a solitary bee peptide.(AU)

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Background Mass spectrometry-guided venom peptide profiling is a powerful tool to explore novel substances from venomous animals in a highly sensitive manner. In this study, this peptide profiling approach is successfully applied to explore the venom peptides of a Japanese solitary carpenter bee, Xylocopa appendiculata (Hymenoptera: Apoidea: Apidae: Anthophila: Xylocopinae: Xylocopini). Although interesting biological effects of the crude venom of carpenter bees have been reported, the structure and biological function of the venom peptides have not been elucidated yet. Methods The venom peptide profiling of the crude venom of X. appendiculata was performed by matrix-assisted laser desorption/ionization-time of flight mass spectroscopy. The venom was purified by a reverse-phase HPLC. The purified peptides were subjected to the Edman degradation, MS/MS analysis, and/or molecular cloning methods for peptide sequencing. Biological and functional characterization was performed by circular dichroism analysis, liposome leakage assay, and antimicrobial, histamine releasing and hemolytic activity tests. Results Three novel peptides with m/z 16508, 1939.3, and 1900.3 were isolated from the venom of X. appendiculata. The peptide with m/z 16508 was characterized as a secretory phospholipase A2 (PLA2) homolog in which the characteristic cysteine residues as well as the active site residues found in bee PLA2s are highly conserved. Two novel peptides with m/z 1939.3 and m/z 1900.3 were named as Xac-1 and Xac-2, respectively. These peptides are found to be amphiphilic and displayed antimicrobial and hemolytic activities. The potency was almost the same as that of mastoparan isolated from the wasp venom. Conclusion We found three novel biologically active peptides in the venom of X. appendiculata and analyzed their molecular functions, and compared their sequential homology to discuss their molecular diversity. Highly sensitive mass analysis plays an important role in this study.(AU)

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Background: Among the hymenopteran insect venoms, those from social wasps and bees - such as honeybee, hornets and paper wasps - have been well documented. Their venoms are composed of a number of peptides and proteins and used for defending their nests and themselves from predators. In contrast, the venoms of solitary wasps and bees have not been the object of further research. In case of solitary bees, only major peptide components in a few venoms have been addressed. Therefore, the aim of the present study was to explore the peptide component profile of the venom from the solitary bee Xylocopa appendiculata circumvolans by peptidomic analysis with using LC-MS. Methods: A reverse-phase HPLC connected to ESI-OrbiTrap MS was used for LC-MS. On-line mass fingerprinting was made from TIC, and data-dependent tandem mass spectrometry gave MSMS spectra. A major peptide component was isolated by reverse-phase HPLC by conventional way, and its sequence was determined by Edman degradation, which was finally corroborated by solid phase synthesis. Using the synthetic specimen, biological activities (antimicrobial activity, mast cell devaluation, hemolysis, leishmanicidal activity) and pore formation in artificial lipid bilayer were evaluated. Results: On-line mass fingerprinting revealed that the crude venom contained 124 components. MS/MS analysis gave 75 full sequences of the peptide components. Most of these are related to the major and novel peptide, xylopin. Its sequence, GFVALLKKLPLILKHLH-NH2, has characteristic features of linear cationic α-helical peptides; rich in hydrophobic and basic amino acids with no disulfide bond, and accordingly, it can be predicted to adopt an amphipathic α-helix secondary structure. In biological evaluation, xylopin exhibited broad-spectrum antimicrobial activity, and moderate mast cell degranulation and leishmanicidal activities, but showed virtually no hemolytic activity. Additionally, the peptide was able to incorporate pores in artificial lipid bilayers of azolectin, confirming the mechanism of the cytolytic activity by pore formation in biological membranes. Conclusions: LC-ESI-MS and MS/MS analysis of the crude venom extract from a solitary bee Xylocopa appendiculata circumvolans revealed that the component profile of this venom mostly consisted of small peptides. The major peptide components, xylopin and xylopinin, were purified and characterized in a conventional manner. Their chemical and biological characteristics, belonging to linear cationic α-helical peptides, are similar to the known solitary bee venom peptides, melectin and osmin. Pore formation in artificial lipid bilayers was demonstrated for the first time with a solitary bee peptide.(AU)

Assuntos

RESUMO

Background Mass spectrometry-guided venom peptide profiling is a powerful tool to explore novel substances from venomous animals in a highly sensitive manner. In this study, this peptide profiling approach is successfully applied to explore the venom peptides of a Japanese solitary carpenter bee, Xylocopa appendiculata (Hymenoptera: Apoidea: Apidae: Anthophila: Xylocopinae: Xylocopini). Although interesting biological effects of the crude venom of carpenter bees have been reported, the structure and biological function of the venom peptides have not been elucidated yet. Methods The venom peptide profiling of the crude venom of X. appendiculata was performed by matrix-assisted laser desorption/ionization-time of flight mass spectroscopy. The venom was purified by a reverse-phase HPLC. The purified peptides were subjected to the Edman degradation, MS/MS analysis, and/or molecular cloning methods for peptide sequencing. Biological and functional characterization was performed by circular dichroism analysis, liposome leakage assay, and antimicrobial, histamine releasing and hemolytic activity tests. Results Three novel peptides with m/z 16508, 1939.3, and 1900.3 were isolated from the venom of X. appendiculata. The peptide with m/z 16508 was characterized as a secretory phospholipase A2 (PLA2) homolog in which the characteristic cysteine residues as well as the active site residues found in bee PLA2s are highly conserved. Two novel peptides with m/z 1939.3 and m/z 1900.3 were named as Xac-1 and Xac-2, respectively. These peptides are found to be amphiphilic and displayed antimicrobial and hemolytic activities. The potency was almost the same as that of mastoparan isolated from the wasp venom. Conclusion We found three novel biologically active peptides in the venom of X. appendiculata and analyzed their molecular functions, and compared their sequential homology to discuss their molecular diversity. Highly sensitive mass analysis plays an important role in this study.(AU)

Assuntos

RESUMO

Abstract Background Mass spectrometry-guided venom peptide profiling is a powerful tool to explore novel substances from venomous animals in a highly sensitive manner. In this study, this peptide profiling approach is successfully applied to explore the venom peptides of a Japanese solitary carpenter bee, Xylocopa appendiculata (Hymenoptera: Apoidea: Apidae: Anthophila: Xylocopinae: Xylocopini). Although interesting biological effects of the crude venom of carpenter bees have been reported, the structure and biological function of the venom peptides have not been elucidated yet. Methods The venom peptide profiling of the crude venom of X. appendiculata was performed by matrix-assisted laser desorption/ionization-time of flight mass spectroscopy. The venom was purified by a reverse-phase HPLC. The purified peptides were subjected to the Edman degradation, MS/MS analysis, and/or molecular cloning methods for peptide sequencing. Biological and functional characterization was performed by circular dichroism analysis, liposome leakage assay, and antimicrobial, histamine releasing and hemolytic activity tests. Results Three novel peptides with m/z 16508, 1939.3, and 1900.3 were isolated from the venom of X. appendiculata. The peptide with m/z 16508 was characterized as a secretory phospholipase A2 (PLA2) homolog in which the characteristic cysteine residues as well as the active site residues found in bee PLA2s are highly conserved. Two novel peptides with m/z 1939.3 and m/z 1900.3 were named as Xac-1 and Xac-2, respectively. These peptides are found to be amphiphilic and displayed antimicrobial and hemolytic activities. The potency was almost the same as that of mastoparan isolated from the wasp venom. Conclusion We found three novel biologically active peptides in the venom of X. appendiculata and analyzed their molecular functions, and compared their sequential homology to discuss their molecular diversity. Highly sensitive mass analysis plays an important role in this study.

RESUMO

Abstract Background: Among the hymenopteran insect venoms, those from social wasps and bees - such as honeybee, hornets and paper wasps - have been well documented. Their venoms are composed of a number of peptides and proteins and used for defending their nests and themselves from predators. In contrast, the venoms of solitary wasps and bees have not been the object of further research. In case of solitary bees, only major peptide components in a few venoms have been addressed. Therefore, the aim of the present study was to explore the peptide component profile of the venom from the solitary bee Xylocopa appendiculata circumvolans by peptidomic analysis with using LC-MS. Methods: A reverse-phase HPLC connected to ESI-OrbiTrap MS was used for LC-MS. On-line mass fingerprinting was made from TIC, and data-dependent tandem mass spectrometry gave MSMS spectra. A major peptide component was isolated by reverse-phase HPLC by conventional way, and its sequence was determined by Edman degradation, which was finally corroborated by solid phase synthesis. Using the synthetic specimen, biological activities (antimicrobial activity, mast cell devaluation, hemolysis, leishmanicidal activity) and pore formation in artificial lipid bilayer were evaluated. Results: On-line mass fingerprinting revealed that the crude venom contained 124 components. MS/MS analysis gave 75 full sequences of the peptide components. Most of these are related to the major and novel peptide, xylopin. Its sequence, GFVALLKKLPLILKHLH-NH2, has characteristic features of linear cationic -helical peptides; rich in hydrophobic and basic amino acids with no disulfide bond, and accordingly, it can be predicted to adopt an amphipathic -helix secondary structure. In biological evaluation, xylopin exhibited broad-spectrum antimicrobial activity, and moderate mast cell degranulation and leishmanicidal activities, but showed virtually no hemolytic activity. Additionally, the peptide was able to incorporate pores in artificial lipid bilayers of azolectin, confirming the mechanism of the cytolytic activity by pore formation in biological membranes. Conclusions: LC-ESI-MS and MS/MS analysis of the crude venom extract from a solitary bee Xylocopa appendiculata circumvolans revealed that the component profile of this venom mostly consisted of small peptides. The major peptide components, xylopin and xylopinin, were purified and characterized in a conventional manner. Their chemical and biological characteristics, belonging to linear cationic -helical peptides, are similar to the known solitary bee venom peptides, melectin and osmin. Pore formation in artificial lipid bilayers was demonstrated for the first time with a solitary bee peptide.

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Abstract:The Neotropical bee Centris (Hemisiella) dichrootricha is a solitary bee that nests in pre-existing cavities that occur in the rain forest. This study describes the nesting biology of C. dichrootricha and its preference for nesting in Cerrado and gallery forest habitats. The study was conducted from January 2012 and December 2013, in Mirador State Park in the municipality of Formosa da Serra Negra, Maranhão State, Brazil. For this, wooden trap-nests of 6, 8, 10, 12, 14 and 16 mm in diameter were used; a total of 300 trap-nests were placed in the gallery forest and Cerrado areas, respectively. Traps were monitored monthly and all completed nests were collected and replaced with empty ones. The nests were then taken to the laboratory to analyze bee development and emergence, nests characteristics and parasites presence. The species used 29 of the trap-nests, which had diameters of 8, 10, 12 and 14 mm. A total of 87 C. dichrootricha specimens emerged. The nests were parasitized by two bee species, Mesocheira bicolor (Apinae) and Coelioxys sp. (Megachilinae), and one fly species, Antrax sp. (Diptera). The highest nesting incidence of 72.4 % was observed in the gallery forest, whereas only 27.6 % in the Cerrado; this difference in habitat use was significant (χ² = 5.56; p < 0.05; DF = 1). For the nests that were built in the gallery forest, 80.9% of the soil originated from the Cerrado. The females were significantly larger than the males (F1, 76 = 595.19; p < 0.001). There were 11 pollen types that belonged to six families. Pollen of the family Malpighiaceae was most frequently used, with four species represented (Byrsonima crassifolia, B. rotunda, B. spicata and Heteropterys sp.). C. dichrootricha showed a preference for nesting in cavities of various diameters in gallery forest sites. The present study provides a novel description of the nesting habits and biology of C. dichrootricha in habitats of Central/Southern Maranhão. C. dichrootricha primarily used resources from the Cerrado, including soil to build their nests, pollen and floral oils; we concluded that gallery forest and Cerrado areas are intrinsically related to the maintenance of local populations of this species. Rev. Biol. Trop. 64 (3): 1041-1056. Epub 2016 September 01.

ResumenCentris (Hemisiella) dichrootricha es una especie de abeja solitaria neotropical, que anida en cavidades preexistentes y vive en la selva tropical. El presente estudio describe la biología de anidación de C. dichrootricha y su preferencia de nidificación por áreas en Cerrado y Bosque de Galería. El área de estudio se localiza en el Parque Estadual de Mirador, municipio de Formosa da Serra Negra, Maranhão. El método empleado fue el de nidos trampa de madera de diferentes diámetros, 6, 8, 10, 12, 14 y 16 mm, colocándose 300 nidos trampa por área. Las trampas fueron monitoreadas mensualmente y todos los nidos terminados fueron recogidos y sustituidos por otros vacíos. Los nidos completos fueron llevados al laboratorio para analizar el desarrollo de la abeja, la emergencia, las características de los nidos y la presencia de parásitos. La especie ocupó 29 nidos de los diámetros de 8, 10, 12 y 14 mm. Emergieron 87 individuos de C. dichrootricha. Los nidos fueron parasitados por tres especies: Mesocheira bicolor (Apinae), Coelioxys sp. (Megachilinae) y Antrax sp. (Diptera). En el Bosque de Galería se presentó la mayor nidificación (72.4 %) y en el Cerrado solamente 27.6 %, de esta forma, hubo diferencias significativas entre los hábitats (χ² = 5.56; p < 0.05; G. L.= 1). Los nidos fundados en el bosque de galería presentaron 80.9 % de sedimento originario del Cerrado. Las hembras fueron significativamente más grandes que los machos (F1, 76 = 595.19; p < 0.001). Hubo 11 tipos de polen pertenecientes a seis familias. Los tipos de polinización de la familia Malpighiaceae fueron los más representativos, con cuatro especies: Byrsonima crassifolia, B. rotunda, B. spicata y Heteropterys sp. C. dichrootricha mostró preferencia por nidificar en cavidades con diámetros variados y en el bosque de galería. El presente estudio contribuye con la descripción de los hábitos de nidificación y la biología de la especie para las áreas de Cerrado en la región centrosur de Maranhão. C. dichrootricha utilizó en su mayoría recursos provenientes del Cerrado, tanto sedimento para construir el nido, como material polínico y aceite floral. Estós datos indican que el bosque de galería y el Cerrado están intrínsecamente relacionados con el mantenimiento y conservación de C. dichrootricha.

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RESUMO

Nests of Hylaeus aff. guaraniticus (Schrottky, 1906) were parasited by females of Gasteruption brachychaetum Schrottky, 1906 in trap nests in São Paulo (Brazil). This is thefirst host record of a Gasteruptiidae in the Neotropical Region. The behavior of a G.brachychaetum female entering a host's nest is described as follows: an inquiline female hovered near the host's nest, landed and detected that a female of H. aff. guaraniticus was inside the nest, waited for the host female to fly out, entered backwards into the nest, remained there for almost six minutes, and then went out the nest. The development time of immature stages of G.brachychaetum varied between 16 and 299 days.

Ninhos de Hylaeus aff. guaraniticus (Schrottky, 1906)foram parasitados por fêmeas de Gasteruption brachychaetum Schrottky, 1906 em ninhos-armadilha em São Paulo (Brasil). Este é o primeiro registro de hospedeiro de um Gasteruptiidae na região Neotropical. O comportamento de uma fêmea entrando no ninho do hospedeiro é descrito: a fêmea inquilina pairou sobre o ninho do hospedeiro, pousou e detectou que a fêmea de H. aff. guaraniticus estava dentro do ninho, esperou a fêmea hospedeira voar para fora do ninho, entrou de costas no ninho, permanecendo no local por quase seis minutos, em seguida, partiu voando. O tempo de desenvolvimento dos imaturos de G.brachychaetum variou entre 16 e 229 dias.