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At least 631 records · Page 35Linked to original sources
PubMed1997

Localization of structural elements of bee venom phospholipase A2 involved in N-type receptor binding and neurotoxicity.

We have shown previously that neurotoxic venom secretory phospholipases A2 (sPLA2s) have specific receptors in brain membranes called N-type receptors that are likely to play a role in the molecular events leading to neurotoxicity of these proteins. The sPLA2 found in honey bee venom is neurotoxic and binds to this receptor with high affinity. In this paper, we have used a number of mutants of bee venom sPLA2 produced in Escherichia coli to determine the structural elements of this protein that are involved in its binding to N-type receptors. Mutations in the interfacial binding surface, in the Ca2+-binding loop and in the hydrophobic channel lead to a dramatic decrease in binding to N-type receptors, whereas mutations of surface residues localized in other parts of the sPLA2 structure do not significantly modify the binding properties. Neurotoxicity experiments show that mutants with low affinity for N-type receptors are devoid of neurotoxic properties, even though some of them retain high enzymatic activity. These results provide further evidence for the involvement of N-type receptors in neurotoxic processes associated with venom sPLA2s and identify the surface region surrounding the hydrophobic channel of bee venom sPLA2 as the N-type receptor recognition domain.

Animals↗
PubMed2002

Developing and establishing bee species as crop pollinators: the example of Osmia spp. (Hymenoptera: Megachilidae) and fruit trees.

The development of a bee species as a new crop pollinator starts with the identification of a pollination-limited crop production deficit and the selection of one or more candidate pollinator species. The process continues with a series of studies on the developmental biology, pollinating efficacy, nesting behaviour, preference for different nesting substrates, and population dynamics of the candidate pollinator. Parallel studies investigate the biology of parasites, predators and pathogens. The information gained in these studies is combined with information on the reproductive biology of the crop to design a management system. Complete management systems should provide guidelines on rearing and releasing methods, bee densities required for adequate pollination, nesting materials, and control against parasites, predators and pathogens. Management systems should also provide methods to ensure a reliable pollinator supply. Pilot tests on a commercial scale are then conducted to test and eventually refine the management system. The process culminates with the delivery of a viable system to manage and sustain the new pollinator on a commercial scale. The process is illustrated by the development of three mason bees, Osmia cornifrons (Radoszkowski), O. lignaria Say and O. cornuta (Latreille) as orchard pollinators in Japan, the USA and Europe, respectively.

Animals↗
PubMed2005

Bee venom, immunostimulant or immunosuppressor? Insight into the effect on matrix metalloproteinases and interferons.

The current evidence has defined conflicting properties for bee venom. The goal of this study was to determine whether bee venom (BV) is an immunosuppressor or immunostimulant. The WEHI-164, HT-1080, and K562 cell lines were used for assaying toxicity, proliferative response, matrix metalloproteinase-2 and -9 (MMP-2 and MMP-9) activity, and interferon production. The Australian and Iranian BV (ABV and IBV) were used at concentrations of 0.025-1 microg/ml in triplicate and 2-fold dilutions. MMP-2 and -9 activities were evaluated using the zymography method. The production of interferons (IFN-alpha and IFN-beta) were assessed using enzyme-linked immunoassay procedure. Our results show no significant difference between two sources of honeybee venom (ABV and IBV) when they are added to an identified cell line, whereas the response of various cell lines against BV could be different. The increasing amounts of ABV and/or IBV (between doses 0.025-0.5 microg/ml) to human monocyte cell line (K562) exhibit a significant increase in proliferative response. Our data show that the immunomodulatory effect of ABV and/or IBV on MMP-2 and MMP-9 activity in both cell culture media, WEHI-164 and K562, is similar. The stimulatory effect of BV on MMP-2 and -9 activities is occurred between doses 0-0.05 microg/ ml. In contrast, the inhibitory effect of BV on these two MMPs is seen at concentrations of >0.05 microg/ml. The ABV and/or IBV has no influence on IFN-alpha production in cell culture media, whereas adding the BV to K562 cell line could significantly increase the production level of IFN-beta only on day 8 posttreatment. We conclude that time- and dose-dependent response as well as the type of treated cell line could determine the immunosuppressive and/or immunostimulant property of bee venom that could be effective in future therapeutic strategies.

Animals↗
PubMed1995

Linkage map of the honey bee, Apis mellifera, based on RAPD markers.

A linkage map was constructed for the honey bee based on the segregation of 365 random amplified polymorphic DNA (RAPD) markers in haploid male progeny of a single female bee. The X locus for sex determination and genes for black body color and malate dehydrogenase were mapped to separate linkage groups. RAPD markers were very efficient for mapping, with an average of about 2.8 loci mapped for each 10-nucleotide primer that was used in polymerase chain reactions. The mean interval size between markers on the map was 9.1 cM. The map covered 3110 cM of linked markers on 26 linkage groups. We estimate the total genome size to be approximately 3450 cM. The size of the map indicated a very high recombination rate for the honey bee. The relationship of physical to genetic distance was estimated at 52 kb/cM, suggesting that map-based cloning of genes will be feasible for this species.

Animals↗
PubMed1998

Quantitative trait loci for honey bee stinging behavior and body size.

A study was conducted to identify quantitative trait loci (QTLs) that affect colony-level stinging behavior and individual body size of honey bees. An F1 queen was produced from a cross between a queen of European origin and a drone descended from an African subspecies. Haploid drones from the hybrid queen were individually backcrossed to sister European queens to produce 172 colonies with backcross workers that were evaluated for tendency to sting. Random amplified polymorphic DNA markers were scored from the haploid drone fathers of these colonies. Wings of workers and drones were used as a measure of body size because Africanized bees in the Americas are smaller than European bees. Standard interval mapping and multiple QTL models were used to analyze data. One possible QTL was identified with a significant effect on tendency to sting (LOD 3.57). Four other suggestive QTLs were also observed (about LOD 1.5). Possible QTLs also were identified that affect body size and were unlinked to defensive-behavior QTLs. Two of these were significant (LOD 3.54 and 5.15).

Animals↗
PubMed2003

American foulbrood and African honey bees (Hymenoptera: Apidae).

We have taken samples of honey from individual beekeepers (N = 64), and of domestic (N = 35) and imported honey (N = 15) retailed in supermarkets in several sub-Saharan countries and cultivated these samples for Paenibacillus larvae subsp. larvae Heyndrickx et al. causing American foulbrood in honey bee colonies. The results are compared with samples of similar backgrounds and treated the same way but collected in Sweden (N = 35). No P. larvae subsp. larvae spores were found in any honey produced in Africa south of the Sahara although honey imported into this region frequently contains the pathogen. Swedish honey frequently contains P. larvae subsp. larvae spores although the general level of visibly infected bee colonies is low (roughly 0.5%). The results suggest that large parts of Africa may be free from American foulbrood. Behavioral studies (hygienic behavior) on Apis mellifera subsp. scutellata Lepeletier in Zimbabwe suggest that hygienic behavior of African bees could influence the apparent low level, or even absence of American foulbrood in large parts of Africa.

Africa↗
PubMedDate not supplied

Genetic control of the honey bee (Apis mellifera) dance language: segregating dance forms in a backcrossed colony.

We studied the genetic control of the dance dialects that exist in the different subspecies of honey bees (Apis mellifera) by observing the variation in dance form observed in a backcross between two lines that showed widely different dance dialects. To do this we generated the reciprocal of the cross performed by Rinderer and Beaman (1995), thus producing phenotypic segregation of dance forms within a single colony rather than between colonies. Our results are consistent with Rinderer and Beaman (1995) in that inheritance of the transition point from round dancing --> waggle dancing is consistent with control by a single locus with more than one allele. That is, we found one dance type to be dominant in the F(1), and observed a 1:1 segregation of dance in a backcross involving the F(1) and the recessive parent. However, we found some minor differences in dance dialect inheritance, with the most significant being an apparent reversal of dominance between our cross (for us "black" is the dominant dialect) and that of Rinderer and Beaman (1995) (they report "yellow" to be the dominant dialect). We also found that our black bees do not perform a distinct sickle dance, whereas the black bees used by Rinderer and Beaman (1995) did perform such a dance. However, our difference in dominance need not contradict the results of Rinderer and Beaman (1995), as there is no evidence that body color and dominance for dance dialect are linked.

Animal Communication↗
PubMed2004

Olfactory eavesdropping by a competitively foraging stingless bee, Trigona spinipes.

Signals that are perceived over long distances or leave extended spatial traces are subject to eavesdropping. Eavesdropping has therefore acted as a selective pressure in the evolution of diverse animal communication systems, perhaps even in the evolution of functionally referential communication. Early work suggested that some species of stingless bees (Hymenoptera, Apidae, Meliponini) may use interceptive olfactory eavesdropping to discover food sources being exploited by competitors, but it is not clear if any stingless bee can be attracted to the odour marks deposited by an interspecific competitor. We show that foragers of the aggressive meliponine bee, Trigona spinipes, can detect and orient towards odour marks deposited by a competitor, Melipona rufiventris, and then rapidly take over the food source, driving away or killing their competitors. When searching for food sources at new locations that they are not already exploiting, T. spinipes foragers strongly prefer M. rufiventris odour marks to odour marks deposited by their own nest-mates, whereas they prefer nest-mate odour marks over M. rufiventris odour marks at a location already occupied by T. spinipes nest-mates. Melipona rufiventris foragers flee from T. spinipes odour marks. This olfactory eavesdropping may have played a role in the evolution of potentially cryptic communication mechanisms such as shortened odour trails, point-source only odour marking and functionally referential communication concealed at the nest.

Analysis of Variance↗
PubMed2006

Evolution of the complementary sex-determination gene of honey bees: balancing selection and trans-species polymorphisms.

The mechanism of sex determination varies substantively among evolutionary lineages. One important mode of genetic sex determination is haplodiploidy, which is used by approximately 20% of all animal species, including >200,000 species of the entire insect order Hymenoptera. In the honey bee Apis mellifera, a hymenopteran model organism, females are heterozygous at the csd (complementary sex determination) locus, whereas males are hemizygous (from unfertilized eggs). Fertilized homozygotes develop into sterile males that are eaten before maturity. Because homozygotes have zero fitness and because common alleles are more likely than rare ones to form homozygotes, csd should be subject to strong overdominant selection and negative frequency-dependent selection. Under these selective forces, together known as balancing selection, csd is expected to exhibit a high degree of intraspecific polymorphism, with long-lived alleles that may be even older than the species. Here we sequence the csd genes as well as randomly selected neutral genomic regions from individuals of three closely related species, A. mellifera, Apis cerana, and Apis dorsata. The polymorphic level is approximately seven times higher in csd than in the neutral regions. Gene genealogies reveal trans-species polymorphisms at csd but not at any neutral regions. Consistent with the prediction of rare-allele advantage, nonsynonymous mutations are found to be positively selected in csd only in early stages after their appearances. Surprisingly, three different hypervariable repetitive regions in csd are present in the three species, suggesting variable mechanisms underlying allelic specificities. Our results provide a definitive demonstration of balancing selection acting at the honey bee csd gene, offer insights into the molecular determinants of csd allelic specificities, and help avoid homozygosity in bee breeding.

Alleles↗
PubMed2006

Evolution of the Yellow/Major Royal Jelly Protein family and the emergence of social behavior in honey bees.

The genomic architecture underlying the evolution of insect social behavior is largely a mystery. Eusociality, defined by overlapping generations, parental brood care, and reproductive division of labor, has most commonly evolved in the Hymenopteran insects, including the honey bee Apis mellifera. In this species, the Major Royal Jelly Protein (MRJP) family is required for all major aspects of eusocial behavior. Here, using data obtained from the A. mellifera genome sequencing project, we demonstrate that the MRJP family is encoded by nine genes arranged in an approximately 60-kb tandem array. Furthermore, the MRJP protein family appears to have evolved from a single progenitor gene that encodes a member of the ancient Yellow protein family. Five genes encoding Yellow-family proteins flank the genomic region containing the genes encoding MRJPs. We describe the molecular evolution of these protein families. We then characterize developmental-stage-specific, sex-specific, and caste-specific expression patterns of the mrjp and yellow genes in the honey bee. We review empirical evidence concerning the functions of Yellow proteins in fruit flies and social ants, in order to shed light on the roles of both Yellow and MRJP proteins in A. mellifera. In total, the available evidence suggests that Yellows and MRJPs are multifunctional proteins with diverse, context-dependent physiological and developmental roles. However, many members of the Yellow/MRJP family act as facilitators of reproductive maturation. Finally, it appears that MRJP protein subfamily evolution from the Yellow protein family may have coincided with the evolution of honey bee eusociality.

Animals↗
PubMed2002

Annotated expressed sequence tags and cDNA microarrays for studies of brain and behavior in the honey bee.

To accelerate the molecular analysis of behavior in the honey bee (Apis mellifera), we created expressed sequence tag (EST) and cDNA microarray resources for the bee brain. Over 20,000 cDNA clones were partially sequenced from a normalized (and subsequently subtracted) library generated from adult A. mellifera brains. These sequences were processed to identify 15,311 high-quality ESTs representing 8912 putative transcripts. Putative transcripts were functionally annotated (using the Gene Ontology classification system) based on matching gene sequences in Drosophila melanogaster. The brain ESTs represent a broad range of molecular functions and biological processes, with neurobiological classifications particularly well represented. Roughly half of Drosophila genes currently implicated in synaptic transmission and/or behavior are represented in the Apis EST set. Of Apis sequences with open reading frames of at least 450 bp, 24% are highly diverged with no matches to known protein sequences. Additionally, over 100 Apis transcript sequences conserved with other organisms appear to have been lost from the Drosophila genome. DNA microarrays were fabricated with over 7000 EST cDNA clones putatively representing different transcripts. Using probe derived from single bee brain mRNA, microarrays detected gene expression for 90% of Apis cDNAs two standard deviations greater than exogenous control cDNAs. [The sequence data described in this paper have been submitted to Genbank data library under accession nos. BI502708-BI517278. The sequences are also available at http://titan.biotec.uiuc.edu/bee/honeybee_project.htm.]

Animals↗
PubMed1994

Foreign-body granuloma and IgE-pseudolymphoma after multiple bee stings.

We report a patient with an unusual combination of an eosinophilic foreign-body granuloma and a pseudolymphoma, with recurrent severe oedema on the forehead, after multiple bee stings. On immunohistology the foreign-body granuloma and lymphoid follicles reacted with monoclonal antibodies against the high- and low-affinity IgE receptors, and against IgE. Prick and intradermal tests with whole-body bee extracts showed positive immediate-type reactions. The eosinophilic granuloma formation and lymphoid follicles may have been induced by a combination of immune complex and cell-mediated hypersensitivity following antigen persistence. Although bee stings are common, as far as we are aware, this complex reaction pattern has not been reported previously.

Animals↗
PubMed2006

Gene expression profiles underlying alternative caste phenotypes in a highly eusocial bee, Melipona quadrifasciata.

To evaluate caste-biased gene expression in Melipona quadrifasciata, a stingless bee, we generated 1278 ESTs using Representational Difference Analysis. Most annotated sequences were similar to honey bee genes of unknown function. Only few queen-biased sequences had their putative function assigned by sequence comparison, contrasting with the worker-biased ESTs. The expression of six annotated genes connected to caste specificity was validated by real time PCR. Interestingly, queens that were developmentally induced by treatment with a juvenile hormone analogue displayed an expression profile clearly different from natural queens for this set of genes. In summary, this study represents an important first step in applying a comparative genomic approach to queen/worker polyphenism in the bee.

Animals↗
PubMed2006

Towards a molecular definition of worker sterility: differential gene expression and reproductive plasticity in honey bees.

We show that differences in the reproductive development of honey bee workers are associated with locus-specific changes to abundance of messenger RNA. Using a cross-fostering field experiment to control for differences related to age and environment, we compared the gene expression profiles of functionally sterile workers (wild-type) and those from a mutant strain in which workers are reproductively active (anarchist). Among the set of three genes that are significantly differentially expressed are two major royal jelly proteins that are up-regulated in wild-type heads. This discovery is consistent with sterile workers synthesizing royal jelly as food for developing brood. Likewise, the relative underexpression of these two royal jellies in anarchist workers is consistent with these workers' characteristic avoidance of alloparental behaviour, in favour of selfish egg-laying. Overall, there is a trend for the most differentially expressed genes to be up-regulated in wild-type workers. This pattern suggests that functional sterility in honey bee workers may generally involve the expression of a suite of genes that effectively 'switch' ovaries off, and that selfish reproduction in honey bee workers, though rare, is the default developmental pathway that results when ovary activation is not suppressed.

Animals↗
PubMed2004

Long-distance gene flow and cross-Andean dispersal of lowland rainforest bees (Apidae: Euglossini) revealed by comparative mitochondrial DNA phylogeography.

Euglossine bees (Apidae; Euglossini) exclusively pollinate hundreds of orchid species and comprise up to 25% of bee species richness in neotropical rainforests. As one of the first studies of comparative phylogeography in a neotropical insect group, we performed a mitochondrial DNA (mtDNA)-based analysis of 14 euglossine species represented by populations sampled across the Andes and/or across the Amazon basin. The mtDNA divergences within species were consistently low; across the 12 monophyletic species the mean intraspecific divergence among haplotypes was 0.9% (range of means, 0-1.9%). The cytochrome oxidase 1 (CO1) divergence among populations separated by the Andes (N = 11 species) averaged 1.1% (range 0.0-2.0%). The mtDNA CO1 data set displayed homogeneous rates of nucleotide substitution, permitting us to infer dispersal across the cordillera long after the final Andean uplift based on arthropod molecular clocks of 1.2-1.5% divergence per million years. Gene flow across the 3000-km breadth of the Amazon basin was inferred from identical cross-Amazon haplotypes found in five species. Although mtDNA haplotypes for 12 of the 14 euglossine species were monophyletic, a reticulate CO1 phylogeny was recovered in Euglossa cognata and E. mixta, suggesting large ancestral populations and recent speciation. Reference to closely related outgroups suggested recent speciation for the majority of species. Phylogeographical structure across a broad spatial scale is weaker in euglossine bees than in any neotropical group previously examined, and may derive from a combination of Quaternary speciation, population expansion and/or long-distance gene flow.

Animals↗
PubMed2004

'Anti-bee' and 'pro-bird' changes during the evolution of hummingbird pollination in Penstemon flowers.

Floral phenotypes may be as much the result of selection for avoidance of some animal visitors as selection for improving the interaction with better pollinators. When specializing on hummingbird-pollination, Penstemon flowers may have evolved to improve the morphological fit between bird and flower, or to exclude less-efficient bees, or both. We hypothesized how such selection might work on four floral characters that affect the mechanics of pollen transfer: anther/stigma exsertion, presence of a lower corolla lip, width of the corolla tube, and angle of flower inclination. We surgically modified bee-pollinated P. strictus flowers changing one trait at a time to make them resemble hummingbird-pollinated P. barbatus flowers, and measured pollen transfer by bumblebees and hummingbirds. Results suggest that, apart from 'pro-bird' adaptations, specific 'anti-bee' adaptations have been important in shaping hummingbird-flowers. Moreover, some trait changes may have been selected for only if changing in concert with other traits.

Adaptation, Biological↗
PubMed1977

Ethological study of African carpenter bees of the genus Xylocopa (Hymenoptera, Anthophoridae).

Over 200 bees of 4 African Xylocopa species were observed for 3 months on the island of Rubondo (L. Victoria, Tanzania). Some 40 burrows were investigated, 100 bees marked. Building techniques are minutely reported; burrow construction simplifies defence and allows re-use by succeeding generations. Food plants, collecting, provisioning and all aspects of ontogenesis are treated, insight given into pupal leg mobility and the much-debated emergence order after eclosion: the first-hatched bee, in the rearmost cell, prepares the way for siblings. Copulation and the copulatory hold are studied using tethered femalefemale, and illustrated. A few colonization experiments are described and s spectrogram of begging sounds given. Meeting of the generations, feeding of the young and nest-defence by young siblings throw light on the evolution of primitively eusocial communities. The known literature is reviewed in each chapter.

Africa↗
PubMed1996

Effects on behaviour and EEG of single chain phospholipases A2 from snake and bee venoms injected into rat brain: search for a functional antagonism.

Three phospholipase A2 (PLA2s), OS1 and OS1 purified from the taipan snake venom Oxyuranus scutellatus scutellatus and bee venom PLA2 were injected to rats by the intracerebroventricular route. OS1 showed no sign of neurotoxicity at doses at which OS2 and bee venom PLA2 produced multiform dose-dependent behavioural effects including motor disturbances (stereotyped movements), compulsive scratching, convulsions and breathing difficulties. EEG recordings showed at the very time when the animal was motionless the induction of several episodes of a low frequency hippocampal theta rhythm, index of long-term changes in synaptic neuroplasticity. Spike-wave discharges were also produced but the occurrence was not systematic. These seizures were often accompanied with behavioural convulsions. Blockers of NMDA receptors and drugs modifying the GABAergic transmission could not abolish the neurotoxic effects of PLA2s except for diazepam (10 mg/kg intraperitoneally) that prevented only OS2-induced disturbances. Blockers of L-type Ca2+ channels and K+ channel openers were also without effect. The toxicity of OS2 and bee venom PLA2 is probably due to their initial specific binding to their neuronal receptor sites.

Animals↗