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At least 415 records · Page 23Linked to original sources

PubMed2000

The interplay between dancing and trophallactic behavior in the honey bee Apis mellifera.

The interplay between the recruitment dance and food-giving trophallactic contacts of returning Apis meellifera foragers was analyzed. Dancing and trophallactic events were recorded for bees returning from a rate feeder that provided 50% weight on weight sucrose solution at a constant flow rate of 5 microl min(-1). Bees that had danced immediately before their trophallactic contact had more recipients per trophallaxis compared with bees that did not dance before. Thus, besides information coded in dancing behavior, dance maneuvers could serve as a stimulus to increase attention of bees located on the dance floor to receive nectar. In addition, the number of bees receiving food during a trophallaxis showed a positive correlation with the probability of dancing immediately after contacting. The time from arrival at the hive to when the first or the subsequent contacts took place presented no correlation with the probability of dancing after trophallaxis. Also, the duration of a trophallaxis was positively correlated with the number of recipients per trophallaxis. These results suggest that returning foragers could receive information during a trophallactic contact with their hive mates that modify thresholds for dancing. Dance maneuvers and trophallactic contacts performed by foraging bees seem to be "mutually" affected.

Animals↗

PubMed2005

Expression of Pax group III genes in the honeybee (Apis mellifera).

Pax group III genes are involved in a number of processes during insect segmentation. In Drosophila melanogaster, three genes, paired, gooseberry and gooseberry-neuro, regulate segmental patterning of the epidermis and nervous system. Paired acts as a pair-rule gene and gooseberry as a segment polarity gene. Studies of Pax group III genes in other insects have indicated that their expression is a good marker for understanding the underlying molecular mechanisms of segmentation. We have cloned three Pax group III genes from the honeybee (Apis mellifera) and examined their relationships to other insect Pax group III genes and their expression patterns during honeybee segmentation. The expression pattern of the honeybee homologue of paired is similar to that of paired in Drosophila, but its expression is modulated by anterior-posterior temporal patterning similar to the expression of Pax group III proteins in Tribolium. The expression of the other two Pax group III genes in the honeybee indicates that they also act in segmentation and nervous system development, as do these genes in other insects.

Amino Acid Sequence↗

PubMed2003

Ultrastructure and bacterial infection of wounds in honey bee ( Apis mellifera) pupae punctured by Varroa mites.

The damage to western honey bee, Apis mellifera, colonies caused by the originally Asian ectoparasitic mite Varroa destructor is mainly a consequence of the infestation of host bee pupae. In the capped brood cell, female mites puncture the host's integument at preferred sites in order to suck haemolymph. Due to repeated feeding by the mother mite and her progeny, these perforations are kept open until shortly before the imaginal moult of the bee. Thereafter scarring takes place, thus preventing microbial infection after the adult bee has emerged from the protected environment of the sealed brood cell. However, colonies of various bacteria were found in the open wounds of about 15-30% of all inspected host pupae with an abundance depended on the level of host brood cell infestation by the mite. The small punctures of the pupal integument are difficult to detect but, by vital staining with trypan blue, the wounds can be visualised. The ultrastructure of the pupal wounds, the bacterial colonies and the scarring process are documented by a series of scanning electron micrographs.

Animals↗

PubMed2004

Prepro-tachykinin gene expression in the brain of the honeybee Apis mellifera.

We have recently identified a tachykinin-related peptide (AmTRP) from the mushroom bodies (MBs) of the brain of the honeybee Apis mellifera L. by using direct matrix-assisted laser desorption/ionization with time-of-flight mass spectometry and have isolated its cDNA. Here, we have examined prepro-AmTRP gene expression in the honeybee brain by using in situ hybridization. The prepro-AmTRP gene is expressed predominantly in the MBs and in some neurons located in the optic and antennal lobes. cDNA microarray studies have revealed that AmTRP expression is enriched in the MBs compared with other brain regions. There is no difference in AmTRP-expressing cells among worker, queen, and drone brains, suggesting that the cell types that express the prepro-AmTRP gene do not change according to division of labor, sex, or caste. The unique expression pattern of the prepro-AmTRP gene suggests that AmTRPs function as neuromodulators in the MBs of the honeybee brain.

Animals↗

PubMed2006

Categorization of visual stimuli in the honeybee Apis mellifera.

Categorization refers to the classification of perceptual input into defined functional groups. We present and discuss evidence suggesting that stimulus categorization can also be found in an invertebrate, the honeybee Apis mellifera, thus underlining the generality across species of this cognitive process. Honeybees show positive transfer of appropriate responding from a trained to a novel set of visual stimuli. Such a transfer was demonstrated for specific isolated features such as symmetry or orientation, but also for assemblies (layouts) of features. Although transfer from training to novel stimuli can be achieved by stimulus generalization of the training stimuli, most of these transfer tests involved clearly distinguishable stimuli for which generalization would be reduced. Though in most cases specific experimental controls such as stimulus balance and discriminability are still required, it seems appropriate to characterize the performance of honeybees as reflecting categorization. Further experiments should address the issue of which categorization theory accounts better for the visual performances of honeybees.

Animals↗

PubMed2005

Allozyme variability and phylogenetic relationships in honey bee (Hymenoptera: Apidae: Apis mellifera) populations from Greece and Cyprus.

Ten gene enzymic systems (alpha-GPDH, AO, MDH, ADH, LAP, SOD, ALP, ACPH, ME, and EST), corresponding to 12 genetic loci, were assayed from five Greek populations representing three subspecies of Apis mellifera, A. m. cecropia (Pthiotida, Kythira), A. m. macedonica (Macedonia), and the "Aegean race" of A. mellifera, which is supposed to be very similar to A. m. adami (Ikaria, Kasos), as well as a population from Cypus (A. m. cypria). ADH( *)-1, ADH( *)-2, and LAP( *) electrophoretic patterns discriminate the Cyprus population from the Greek populations. MDH( *)-1, EST( *)-3, SOD( *), ALP( *), and ME( *) loci were found to be polymorphic in almost all populations. The observed heterozygosity was found to range from 0.066 to 0.251. Allele frequencies of all loci were used to estimate Nei's genetic distance, which was found to range between 0.011 and 0.413 among the populations studied. UPGMA and neighbor-joining phylogenetic trees obtained by genetic distance matrix methods, as well as a Wagner tree based on the discrete character parsimony method, support the hypothesis that the most distant population is that from Cyprus. Our allozymic data support A. m. cypria as a distinct subspecies, but there was no allozymic support for the distinction of the other subspecies existing in Greece.

Animals↗

PubMed2006

Mitochondrial DNA diversity and genetic differentiation of the honeybee (Apis cerana) in Thailand.

Genetic diversity of the honeybee (Apis cerana) in Thailand collected from north, northeast, the central region, peninsular Thailand, and Samui Island (n = 181) was examined by PCR-RFLP of ATPase6-ATPase8. Interestingly, 78 individuals (43.09%) of the southern-latitude bees exhibited length heteroplasmy of the PCR product. The gel-eluted ATPase6-ATPase8 (825 bp) of each bee was restricted with TaqI, SspI, and VspI, respectively. Eight mitotypes were generated and revealed biogeographic differentiation between conspecific samples of A. cerana. AAA, ACA, AAD, BAA, ADA, and ABA were found only in the north-to-central samples (north, northeast, and central region); BBB and BBC were found in the southern-latitude bees; and BBC was restrictively found in the Samui sample. Large genetic distances were observed between each of the north-to-central samples and peninsular Thailand and Samui samples, but lower levels of genetic distance were found within each region. Geographic heterogeneity and phylogenetic analyses indicated that Thai A. cerana could be genetically differentiated into northern Thailand, peninsular Thailand, and Samui Island populations.

Animals↗

PubMed2005

Methyl parathion modifies foraging behaviour in honeybees (Apis mellifera).

We examined the effects of sublethal doses of an organophosphorus insecticide, Methyl Parathion (MeP), on the foraging behaviour of honeybees (Apis mellifera ligustica) in a flight cage. The results revealed that MeP modified the frequency of visits to a feeding station to which the bees had previously been trained. A dose of 50 ng per animal elicited an increase in the frequency of visits to the feeder, compared to control animals. A dose of 10 ng, on the other hand, led initially to a decrease in the visit frequency, followed by an increase to a level above that of the controls. A hypothesis is presented to account for the way in which MeP affects foraging behaviour. We propose that the behavioural assay presented here could be useful as a preliminary screening test to study sublethal effects of pesticides on foraging performance in honeybees.

Animals↗

PubMed2005

Pheromone communication in the honeybee (Apis mellifera L.).

Recent studies have demonstrated a remarkable and unexpected complexity in social insect pheromone communication, particularly for honeybees (Apis mellifera L.). The intricate interactions characteristic of social insects demand a complex language, based on specialized chemical signals that provide a syntax that is deeper in complexity and richer in nuance than previously imagined. Here, we discuss this rapidly evolving field for honeybees, the only social insect for which any primer pheromones have been identified. Novel research has demonstrated the importance of complexity, synergy, context, and dose, mediated through spatial and temporal pheromone distribution, and has revealed an unprecedented wealth of identified semiochemicals and functions. These new results demand fresh terminology, and we propose adding "colony pheromone" and "passenger pheromone" to the current terms sociochemical, releaser, and primer pheromone to better encompass our growing understanding of chemical communication in social insects.

Animal Communication↗

PubMed2006

Beyond 9-ODA: sex pheromone communication in the European honey bee Apis mellifera L.

The major component of the mandibular gland secretion of queen honeybees (Apis mellifera L.), 9-ODA ((2E)-9-oxodecenoic acid), has been known for more than 40 yr to function as a long-range sex pheromone, attracting drones at congregation areas and drone flyways. Tests of other mandibular gland components failed to demonstrate attraction. It remained unclear whether these components served any function in mating behavior. We performed dual-choice experiments, using a rotating drone carousel, to test the attractiveness of 9-ODA compared to mixtures of 9-ODA with three other most abundant components in virgin queen mandibular gland secretions: (2E)-9-hydroxydecenoic acid (9-HDA), (2E)-10-hydroxydecenoic acid (10-HDA), and p-hydroxybenzoate (HOB). We found no differences in the number of drones attracted to 9-ODA or the respective mixtures over a distance. However, adding 9-HDA and 10-HDA, or 9-HDA, 10-HDA, and HOB to 9-ODA increased the number of drones making contact with the baited dummy. On the basis of these results, we suggest that at least 9-HDA and 10-HDA are additional components of the sex pheromone blend of A. mellifera.

Animal Communication↗

PubMed2006

Virgin queen mandibular gland signals of Apis mellifera capensis change with age and affect honeybee worker responses.

The mandibular gland secretions of Apis mellifera capensis virgin queens were analyzed by gas chromatography-mass spectroscopy. Changes in the patterns of the mandibular gland volatiles of A. m. capensis virgin queens were followed from emergence until 14-d old. Ontogenetic changes in the mandibular gland secretions were largely quantitative in nature, delineating the age categories (global R = 0.612, P = 0.001), except for 7- and 14-d-old queens, which cannot be separated on their mandibular gland profiles (P = 0.2). (E)-9-Oxodec-2-enoic acid (9ODA) contributes most and most consistently to the dissimilarity between groups as well as the similarity within groups. Worker reactions to introduced virgin queens of various ages were recorded. Workers showed a significant increase in hostile reactions as queens aged (r = 0.615, N = 20, P < 0.05). Consequently, worker reactions and relative 9ODA production exhibit a positive queen age-dependent response.

Animals↗

PubMed2006

Study of the interaction between Apis mellifera venom and micro-heterogeneous systems.

The bee venom, used in treatment of inflammatory and articular diseases, is a complex mixture of peptides and enzymes and the presence of tryptophan allows the investigation by fluorescence techniques. Steady state and time-resolved fluorescence spectroscopy were used to study the interaction between bee venom extracted from Apis mellifera and three micro heterogeneous systems: sodium dodecylsulphate (SDS) micelles, sodium dodecylsulphate-poly(ethylene oxide) (SDS-PEO) aggregates, and the polymeric micelles LUTROL F127, formed by poly(ethylene oxide)-poly(propylene oxide)- poly(ethylene oxide). Fluorescence parameters in buffer solution were typical of peptides containing tryptophan exposed to the aqueous medium, and they gradually changed upon the addition of surfactant and polymeric micelles, demonstrating the interaction of the peptides with the micro heterogeneous systems. Quenching experiments were carried out using the N-alkylpyridinium ions (ethyl, hexyl, and dodecyl) as quenchers. In buffer solution the quenching has low efficiency and is independent of the alkyl chain length of the quencher. In the presence of the micro heterogeneous systems the extent of static and dynamic quenching enhanced, showing that both fluorophore and quenchers reside in the microvolume of the aggregates. The more hydrophobic quencher (dodecyl pyridinium ion) provides higher values for K (SV) and dynamic quenching constants, and SDS-PEO aggregates are most efficient to promote interaction between peptides and alkyl pyridinium ions. The results proved that bee venom interacts with drug delivery micelles of the copolymer LUTROL F127.

Animals↗

PubMed2006

Use of surfactants as plasticizers in preparing solid dispersions of poorly soluble API: stability testing of selected solid dispersions.

PURPOSE: The purpose of the study is to evaluate the effect of surfactant-plasticizers on the physical stability of amorphous drug in polymer matrices formed by hot melt extrusion. METHOD: Solid dispersions of a poorly soluble drug were prepared using PVP-K30, Plasdone-S630, and HPMC-E5 as the polymeric carriers and surfactants as plasticizers. The solid dispersions were produced by hot melt extrusion at temperatures 10 degrees C above and below the glass transition temperature (Tg) of the carrier polymers using a 16 mm-Haake Extruder. The surfactants tested in this study included Tween-80 and Docusate Sodium. The particle size of the extrudate was reduced to have mean of 100-200 micron. The physical stability of the solid dispersions produced was monitored at 30 degrees C/60% for six-months and at 60 degrees C/85% for two-months in open HDPE bottles. Modulated differential scanning calorimetry, polarized light microscopy, powder X-ray diffraction and dissolution testing was performed to assess the physical stability of solid dispersions upon stress testing. RESULTS: The dispersions containing HPMC-E5 were observed especially to be susceptible to physical instability under an accelerated stress conditions (60 degrees C/85%RH) of the solid dispersion. About 6% conversion of amorphous drug to crystalline form was observed. Consequently, the system exhibits similar degree of re-crystallization upon addition of the surfactant. However, under 30 degrees C/60%RH condition, the otherwise amorphous Drug-HPMC-E5 system has been destabilized by the addition of the surfactant. This effect is much more reduced in the extruded solid dispersions where polymeric carriers such as Plasdone S-603 and PVP-K30 (in addition to surfactants) are present. Furthermore, the drug release from the solid dispersions was unaffected at the stress conditions reported above. CONCLUSIONS: Possible reasons for the enhanced stability of the dispersions are due to the surfactants ability to lower the viscosity of the melt, increase the API solubility and homogeneity in the carrier polymer. In contrast, while it is possible for the surfactants to destabilize the system by lowering the Tg and increasing the water uptake, the study confirms that this effect is minimal. By and large, the surfactants appear to be promising plasticizers to produce solid dispersions by hot melt extrusion, in so doing improving dissolution rate without compromising the physical stability of the systems.

Calorimetry, Differential Scanning↗

PubMed2005

Isolation and characterization of some hydroxy fatty and phosphoric acid esters of 10-hydroxy-2-decenoic acid from the royal jelly of honeybees (Apis mellifera).

The present work characterizes novel FA in the royal jelly of honeybees (Apis mellifera). TLC analysis showed that the chloroform/methanol extract obtained from royal jelly consists mainly of FA. The FABMS spectrum of this extract gave several ion peaks due to compounds with higher M.W. than those of the FA so far reported. The methanol extract was found to contain unknown phospholipids. By means of reversed-phase HPLC with various solvent systems, 13 compounds were obtained in pure state. Their structures including absolute configurations were determined by chemical, NMR, and MS spectral analysis. Six compounds were identified as novel mono- or di-esters of 10-hydroxy-2E-decenoic acid in which the hydroxyl group was esterified by another FA unit, and one was hydroxy-2E-decenoic acid 10-phosphate. In addition, we demonstrated that 9-hydroxy-2E-decenoic acid exists as a mixture of optical isomers.

Animals↗

PubMed1996

Characterisation of dopamine receptors in insect (Apis mellifera) brain.

In vitro binding experiments using the vertebrate D1 dopamine receptor ligand [3H]SCH23390 and the vertebrate D2 dopamine receptor ligand [3H]spiperone were conducted on membrane preparations of honey bee (Apis mellifera) brain. Specific binding of [3H]SCH23390 was saturable and reversible. Analysis of saturation data gave an apparent Kd of 6.3 +/- 1.0 nM and Bmax of 1.9 +/- 0.2 pmol/mg protein for a single class of binding sites. The specificity of high affinity [3H]SCH23390 binding was confirmed in displacement experiments using a range of dopaminergic antagonists and agonists. The rank order of potency for antagonists was: R(+)-SCH23390 > cis-(Z)-flupentixol > or = chlorpromazine > fluphenazine > S(+)-butaclamol > spiperone. R(+/-)-SKF38393 and dopamine were the most effective agonists tested. [3H]SCH23390 labels a site in bee brain that is similar, but not identical to the vertebrate D1 dopamine receptor subtype. [3H]Spiperone also bound with high affinity to bee brain homogenates. Scatchard analysis of [3H]spiperone saturation data revealed a curvilinear plot suggesting binding site heterogeneity. The high affinity site had a apparent Kd of 0.11 +/- 0.02 nM and Bmax of 9.2 +/- 0.5 fmol/mg protein. The calculated values for the low affinity site were a Kd of 19.9 nM and Bmax of 862 fmol/mg protein. Kinetic analyses also indicated that [3H]spiperone recognises a heterogeneous population of sites in bee brain. Furthermore, agonist competition studies revealed a phenolaminergic as well as a dopaminergic component to [3H]spiperone binding in bee brain. The rank order of potency of dopaminergic antagonists in competing for [3H]spiperone binding was: spiperone > fluphenazine > S(+)-butaclamol > domperidone > R(+)-SCH23390 > S(-)-sulpiride.

Animals↗

PubMed1975

Ultrastructural analysis of the freeze-etched spore envelope of the microsporidian, Nosema apis Zander.

The outer limiting layer of the spore coat of Nosema apis is relatively smooth. The inner limiting layer shows two fractured faces, the concave face carrying many stud-like projections, 120 nm long and 50 nm high, while the convex face carries numerous depressions which are complementary to the projections. In addition, the convex face bears 7 nm particles. In between the outer and inner limiting layers lies the thick homogeneous portion of spore coat which is comprised of numerous microfibres, each 9 nm in diameter. These microfibres resemble those in the freeze-etched host endocuticle. Next to the inner limiting layer of the spore coat are double spore membranes. The convex faces of these spore membranes have a dense population of particles, each 7 nm in diameter.

Animals↗

PubMed1988

5-Hydroxytryptamine in the venom of the honey bee (Apis mellifera L.): variation with season and with insect age.

We used liquid chromatography with electrochemical detection to show that 5-HT is present in the venom of worker honey bees (Apis mellifera L.). Immunohistochemical demonstration of 5-HT-like immunoreactivity within the venom reservoir supports this finding. Measurements were made on bees of known age at various times during the summer season. The amount of 5-HT in the venom system varies with the age of the bee and with the time of year at which the bees reached a specific age. 5-HT is shown to be a component of pure venom, rather than simply present in venom gland and reservoir tissues, by its presence in venom collected by electrical 'milking' of worker bees.

Age Factors↗

PubMed1995

Toxinology of venoms from the honeybee genus Apis.

The venoms of Apis dorsata, A. cerana, A. florea, and three different populations of A. mellifera were compared for lethal activity toward mice. All venoms exhibited identical activities, a finding consistent with recent evolutionary history within the genus. Young queen honeybees use their venoms only for stinging other queens and possess a venom only half as lethal to mice as worker venom, and by the time queens are 1-2 years of age their venom has become essentially inactive. Phospholipase A2 is the most lethal of the honeybee venom peptides, whereas melittin, which is only slightly less lethal, is the most abundant. Concurrent analyses of melittin, phospholipase, and the combination of the two at their natural 3:1 mixture in bee venom revealed that the lethal activity of the mixture was about the same as native honeybee venom. This value was less than that for either melittin or phospholipase alone and indicates that synergism of the two peptides is not occurring. The results are consistent with independent lethal activities for the venom components, and show that melittin is not only the dominant, but also the main lethal component in honeybee venom.

Animals↗