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PubMed2005

Molecular cloning and expression of a hexamerin cDNA from the honey bee, Apis mellifera.

A cDNA encoding a hexamerin subunit of the Africanized honey bee (Apis mellifera) was isolated and completely sequenced. In the deduced translation product we identified the N-terminal sequence typical of the honey bee HEX 70b hexamerin. The genomic sequence consists of seven exons flanked by GT/AT exon/intron splicing sites, which encode a 683 amino acid polypeptide with an estimated molecular mass of 79.5 kDa, and pI value of 6.72. Semi-quantitative RT-PCR revealed high levels of Hex 70b message in larval stages, followed by an abrupt decrease during prepupal-pupal transition. This coincides with decaying titers of juvenile hormone (JH) and ecdysteroids that is the signal for the metamorphic molt. To verify whether the high Hex 70b expression is dependent on high hormone levels, we treated 5th instar larvae with JH or 20-hydroxyecdysone (20E). In treated larvae, Hex 70b expression was maintained at high levels for a prolonged period of time than in the respective controls, thus indicating a positive hormone regulation at the transcriptional level. Experiments designed to verify the influence of the diet on Hex 70b expression showed similar transcript amounts in adult workers fed on a protein-enriched diet or fed exclusively on sugar. However, sugar-fed workers responded to the lack of dietary proteins by diminishing significantly the amount of HEX 70b subunits in hemolymph. Apparently, they use HEX 70b to compensate the lack of dietary proteins.

Amino Acid Sequence↗
PubMed2006

Thermal history influences diapause development in the solitary bee Megachile rotundata.

Respiration rate, time to pupation and the expression patterns of selected genes were examined during the diapause to post-diapause transition in the alfalfa leafcutting bee, Megachile rotundata held at constant 4 degrees C in winter storage. Respiration quotients were at or below 0.7 from December to May and then increased to over 0.8 in June and July. The time required for prepupae to reach the pupal stage following transfer to 29 degrees C decreased from 23 days in December to 10 days in July. HSP70 was expressed at a consistently high level in all the diapausing prepupae stored at 4 degrees C. In contrast, we demonstrated previously that HSP70 expression in diapausing prepupae maintained under field conditions began decreasing after December and was expressed at trace levels in the June samples. Transferring prepupae stored at 4 to 25 degrees C at monthly intervals from December to July induced a significant decrease in HSP70. Levels of HSC70 showed no changes during the transition to post-diapause development in prepupae maintained at 4 degrees C. Transferring the prepupae to 25 degrees C during the April-June time interval elicited an increase in HSC70 expression. HSP90 was expressed at a consistent level in prepupae stored at 4 degrees C but decreased to very low levels after being transferred to 25 degrees C in December-February prepupae: no decrease was noted in the April-July prepupae. Actin was expressed at trace levels in the diapausing prepupae maintained at 4 degrees C and increased slightly in the post-diapausing pupae. Transferring prepupae stored at 4 to 25 degrees C at monthly intervals from December to July induced an increase in actin expression. These results indicate that the level of gene expression for selected genes in diapausing and post-diapause bees is highly influenced by their thermal history.

Actins↗
PubMedDate not supplied

Open-air-nesting honey bees Apis dorsata and Apis laboriosa differ from the cavity-nesting Apis mellifera and Apis cerana in brood hygiene behaviour.

The cavity-nesting Apis mellifera and Apis cerana bees detect, uncap, and remove diseased brood. The hygiene behaviour of open-air-nesting bees Apis dorsata and Apis laboriosa was investigated in India and Nepal. Sealed A. dorsata pupae were pin-killed or deep-frozen. The workers removed 73 or 37% of damaged pin-killed pupae depending on the diameter of the pins, and only 7% of the frozen undamaged pupae. Migrating A. dorsata and A. laboriosa left unopened the sealed brood in deserted combs. Thus, A. dorsata and A. laboriosa do not open undamaged cells with dead brood. This behaviour is a more efficient mechanism in preventing the spread of diseases and parasitic mites than uncapping and removing dead pupae by A. mellifera and A. cerana. It may be beneficial for migrating A. dorsata and A. laboriosa to temporarily disuse part of the comb cells in exchange for arresting the mites there and thus reducing the increase of their population.

Animals↗
PubMed2006

Cytological variation and pathogenicity of the bumble bee parasite Nosema bombi (Microspora, Nosematidae).

In three field seasons, 2003-2005, bumble bees were collected in southern Sweden and eastern Denmark in search of microsporidian parasites. Of the 16 bumble bee species studied, microsporidia were found in Bombus hortorum, Bombus hypnorum, Bombus lapidarius, Bombus lucorum, Bombus pascuorum, Bombus pratorum, Bombus ruderarius, Bombus subterraneus and Bombus terrestris. Only one microsporidian species, Nosema bombi, was recorded. A microsporidium found in B. pratorum differed cytologically from microsporidia of the other host species. In the most frequently infected host, B. terrestris, the prevalence was 20.6%. Totally 1049 specimens were dissected. The light microscopic and ultrastructural cytology and pathology of N. bombi is described with focus on the variation recorded. Variation was especially prominent in the shape, size and coupling of spores, and in the length and arrangement of the polar filament. In four host species microsporidian infection was restricted to peripheral fat cells.

Animals↗
PubMed2005

Gene expression patterns associated with queen honey bee longevity.

The oxidative stress theory of aging proposes that accumulation of oxidative damage is the main proximate cause of aging and that lifespan is determined by the rate at which this damage occurs. Two predictions from this theory are that long-lived organisms produce fewer ROS or have increased antioxidant production. Based in these predictions, molecular mechanisms to promote longevity could include either changes in the regulation of mitochondrial genes that affect ROS production or elevated expression of antioxidant genes. We explored these possibilities in the honey bee, a good model for the study of aging because it has a caste system in which the same genome produces both a long-lived queen and a short-lived worker. We measured mRNA levels for genes encoding eight of the most prominent antioxidant enzymes and five mitochondrial proteins involved in respiration. The expression of antioxidant genes generally decreased with age in queens, but not in workers. Expression of most mitochondrial genes, in particular CytC, was higher in young queens, but these genes showed a faster age-related decline relative to workers. One exception to this trend was COX-I in thorax. This resulted in higher COX-I/CytC ratios in old queens compared to old workers, which suggests caste-specific differences in mitochondrial function that might be related to the caste-specific differences in longevity. Queen honey bee longevity appears to have evolved via mechanisms other than increased antioxidant gene expression.

Aging↗
PubMed2004

The rectum of Oxaea flavescens (Andrenidae) has a specialized structure among bees.

The rectum of the bee Oxaea flavescens contains six hollow rectal papillae, in contrast to rectal pads found in others Hymenoptera. The rectal epithelium is formed by cubical cells with structural specializations for fluid transport, such as apical plasma membrane invaginations, endocytic vesicles, scalariform junctions, wide extracellular space and double-membrane vesicles. Globular-shaped cells form the rectal papillae with surface plasma membrane invaginations that vary from small depressions to very large sinuses. The cell-cell contact is narrow, exhibiting extensive regions with scalariform junction, while cytoplasmic free ribosome-like material is prominent. These ultrastructural features are discussed in relation to their role in excretion in this bee.

Animals↗
PubMed2006

Cloning and characterization of a third isoform of corazonin in the honey bee Apis mellifera.

The precursor of the insect hormone corazonin has been cloned from the honey bee Apis mellifera. The precursor predicts a novel isoform of corazonin, pQTFTYSHGWTNamide, which was confirmed by tandem mass spectrometry. Although Apis corazonin differs only by a glutamine/threonine substitution from [His7]-corazonin, it is considerably less active in the dark color inducing assay on albino locusts. Whole mount fluorescence immunohistochemistry of the central nervous system of the honey bee showed a pattern similar to the ones described for other insects. Four neurons of the lateral protocerebrum project axons towards the retrocerebral complex. It is unlikely that Apis corazonin is present in all hymenopteran species since the presence of this peptide could not be demonstrated by means of mass spectrometry in the retrocerebral complex of the red wood ant Formica rufa and the wasp Vespula saxonica. Instead, we found masses corresponding with [Arg7]- and [His7]-corazonin respectively, suggesting that some of the corazonin isoforms originated late during evolution in different insect orders.

Amino Acid Sequence↗
PubMed2005

Spatial epidemiology of the Asian honey bee mite (Varroa destructor) in the North Island of New Zealand.

We describe the spatial epidemiology of Varroa destructor infestation among honey bee apiaries in the greater Auckland area of the North Island of New Zealand. The study population was comprised of 641 apiaries located within the boundaries of the study area on 11 April 2000. Cases were those members of the study population declared Varroa-infested on the basis of testing conducted between April and June 2000. The odds of Varroa was highest in apiaries in the area surrounding transport and storage facilities in the vicinity of Auckland International Airport. A mixed-effects geostatistical model, accounting for spatial extra-binomial variation in Varroa prevalence, showed a 17% reduction in the odds of an apiary being Varroa infested for each kilometre increase in the squared distance from the likely site of incursion (95% Bayesian credible interval 7-28%). The pattern of spatially autocorrelated risk that remained after controlling for the effect of distance from the likely incursion site identified areas thought to be 'secondary' foci of Varroa infestation initiated by beekeeper-assisted movement of infested bees. Targeted investigations within these identified areas indicated that the maximum rate of local spread of Varroa was in the order of 12 km/year (interquartile range 10-15 km/year).

Animals↗
PubMed2002

Virulence and site of infection of the fungus, Hirsutella thompsonii, to the honey bee ectoparasitic mite, Varroa destructor.

The Varroa mite, Varroa destructor, is recognized as the most serious pest of both managed and feral Western honey bee (Apis mellifera) in the world. The mite has developed resistance to fluvalinate, an acaricide used to control it in beehives, and fluvalinate residues have been found in the beeswax, necessitating an urgent need to find alternative control measures to suppress this pest. Accordingly, we investigated the possibility of using the fungus, Hirsutella thompsonii, as a biocontrol agent of the Varroa mite. Among the 9 isolates of H. thompsonii obtained from the University of Florida and the USDA, only the 3 USDA isolates (ARSEF 257, 1947 and 3323) were infectious to the Varroa mite in laboratory tests. The mite became infected when it was allowed to walk on a sporulating H. thompsonii culture for 5 min. Scanning electron micrographs revealed that the membranous arolium of the mite leg sucker is the focus of infection where the fungal conidia adhered and germinated. The infected mites died from mycosis, with the lethal times to kill 50% (LT(50)s) dependent on the fungal isolates. Thus, the LT(50)s were 52.7, 77.2, and 96.7h for isolates 3323, 257, and 1947, respectively. Passage of H. thompsonii through Varroa mite three times significantly reduced the LT(50)s of isolates 257 and 1947 (P<0.05) but not the LT(50) of isolate 3323. The fungus did not infect the honey bee in larval, prepupal, pupal, and adult stages under our laboratory rearing conditions. Our encouraging results suggest that some isolates of H. thompsonii have the potential to be developed as a biocontrol agent for V. destructor. However, fungal infectivity against the mites under beehive conditions needs to be studied before any conclusion can be made.

Animals↗
PubMed2003

Diverse origins of tetracycline resistance in the honey bee bacterial pathogen Paenibacillus larvae.

Paenibacillus larvae is the causative agent of the important honey bee larval disease American Foulbrood (AFB). This pathogen has been treated in bee colonies by a single registered antibiotic, oxytetracycline (OTC), for fifty years. Recently, widespread resistance to OTC has been reported. In this study, the degree of antibiotic resistance was contrasted with DNA sequence variation for 125 P. larvae isolates collected in North America. Resistance was uncorrelated with bacterial haplotype, suggesting either that resistance has evolved multiple times in P. larvae or that resistance involves recent horizontal transfer via a non-genomic (e.g., plasmid or conjugal transposon) route. The recency of OTC resistance in P. larvae across this broad survey area underscores the need to manage foulbrood infections carefully and to monitor populations for resistance.

Animals↗
PubMed2003

Partial nectar loads as a cause of multiple nectar transfer in the honey bee (Apis mellifera): a simulation model.

Honey bee foragers transfer their nectar loads to receiver bees within the nest. Surprisingly, they often transfer to more than one receiver (published values range from 1.9 to 2.7). Several adaptive hypotheses have been proposed to explain why multiple transfer occurs. One hypothesis, information improvement, states that multiple transfer arises as an adaptive forager-driven process. Foragers use the delay in finding a receiver to assess the relative work capacities of foragers and receivers, performing recruitment dances when appropriate. Multiple transferring improves their delay information. We used a stochastic simulation model to investigate the non-adaptive partial loads hypothesis. We determined the extent to which partial crop loads and receiver filling and emptying rules (i.e. how much nectar to accept before leaving the transfer area) can cause multiple transfer. As many as 1.9 nectar transfers per returning forager were generated within biologically realistic parameter space. We suggest that much multiple transfer arises as a non-adaptive consequence of partitioning nectar foraging between foragers and receivers, but that this will also result in foragers having better information about the relative work capacities of foragers and receivers as a useful consequence. We suggest that the number of transfers caused by partial loads could also be increased by an adaptive forager-driven effort to improve their information concerning the balance of foragers and receivers and we outline a framework wherein the information improvement hypothesis can be directly tested.

Adaptation, Psychological↗
PubMed1994

Deliberate bee sting challenge of patients receiving maintenance venom immunotherapy at 3-month intervals.

BACKGROUND: A large part of the cost and inconvenience associated with venom immunotherapy (VIT) is related to the need for monthly treatments. Since VIT is advocated for at least 3 to 5 years, and occasionally longer, reducing the number of venom injections may cut down significantly on both cost and inconvenience. OBJECTIVE: We evaluated whether maintenance VIT given every 3 months is both safe and effective regarding reactions to treatment injections or field re-stings and lack of systemic reaction (SR) to deliberate challenge sting. METHODS: The standard 1-month interval was gradually extended to 3 months in 28 patients (mean age 26 years, range 7 to 76) allergic to bee venom (BV), yellow jacket venom, or both venoms. Nineteen patients allergic to BV were deliberately challenged by a live bee sting. In 15 patients the original SR in the field was moderate; in one patient it was mild; and in three patients it was severe. RESULTS: Mean duration receiving standard maintenance VIT before extending the 1-month interval was 17 months. No patient had an SR while receiving the 3-month VIT therapy. Two patients experienced four field re-stings while receiving the 3-month therapy with no reaction. After the live challenge, there was mild urticaria in a single patient; no SR developed in the rest of the patients. CONCLUSION: For young patients allergic to BV whose initial SR is mild to moderate and who have already received 1-month VIT for longer than 17 months, the maintenance interval may safely be extended to 3 months while preserving its protective activity against re-stings.

Adolescent↗
PubMed1995

Natural and recombinant enzymatically active or inactive bee venom phospholipase A2 has the same potency to release histamine from basophils in patients with Hymenoptera allergy.

BACKGROUND: A complementary DNA encoding the major bee venom allergen phospholipase A2 (PLA) has been characterized recently. Recombinant PLA was produced in Escherichia coli and purified to apparent homogeneity. Natural PLA was compared with recombinant PLA in its ability to release histamine from blood basophils. METHODS: A synthetic gene encoding the mature form of PLA was expressed in E. coli, and the polypeptide was purified to homogeneity by affinity chromatography and refolded, yielding fully enzymatically active PLA. In addition, we have produced a genetically engineered enzymatically inactive variant by substitution of a single amino acid residue in the catalytic center. A standard histamine release assay was used to compare the potency of natural PLA with correctly folded enzymatically active and inactive recombinant PLA to release histamine from blood basophils of nine patients with bee venom allergy. RESULTS: Recombinant enzymatically active PLA and purified natural protein were equally effective in releasing histamine from sensitized basophils. By comparing the histamine-releasing capacity of enzymatically active and inactive recombinant allergen, we further demonstrate that catalytic activity is not a requirement for allergenicity in the effector phase. Denaturation of natural PLA or incorrect folding of recombinant protein resulted in a total loss of allergenic potency. CONCLUSION: We demonstrate the feasibility of producing native-like recombinant allergens with or without enzymatic activity. We also provide evidence for the requirement of correct three-dimensional structure of PLA to induce histamine release from basophils and thus evidence for its recognition by IgE.

Bee Venoms↗
PubMed2000

Optic neuropathy occurring after bee and wasp sting.

OBJECTIVE: To inform ophthalmologists about bee and wasp sting-related optic neuropathy. DESIGN: Two case reports and literature review. METHODS: Review of two cases, clinical history, laboratory testing, and follow-up. RESULTS: Two cases of bee and wasp sting optic neuritis are described and five additional cases of optic neuritis occurring after Hymenoptera sting are reviewed from the English language literature. These cases share certain characteristics, including acute to subacute onset of symptoms; moderate to severe visual loss followed by significant visual recovery; edematous and hemorrhagic optic discs; and central or cecocentral scotomas. CONCLUSIONS: Acute optic neuropathy may follow Hymenoptera sting to the face.

Adult↗
PubMed1998

sn-Glycerol-3-phosphate dehydrogenase in the honey bee Apis mellifera -an unusual phenotype associated with the loss of introns.

In comparison with the numerous Drosophila species and the mouse, the Gpdh gene in the honey bee Apis mellifera lacks most introns. This prevents the gene from producing different GPDH isoforms by alternative splicing, which occurs in Drosophila melanogaster. The sequences of the cDNA and genomic Gpdh of A. mellifera are described and show that at the amino acid level they share 84% similarity and 71% identity with D. melanogaster. The identity at the nucleotide level is 62% in the coding region, but no significant similarities were detected in the UTRs. Northern analyses revealed an accumulation of unspliced Gpdh pre-mRNA in the honey bee, probably reflecting splicing inefficiency, although it is also possible that splicing is a regulated step in Gpdh expression in A. mellifera. It is suggested that the intron loss occurred via reverse transcription of a mature Gpdh transcript.

Alternative Splicing↗
PubMed2001

Aging and development in social insects with emphasis on the honey bee, Apis mellifera L.

Honey bee colonies typically consist of about 20-40 thousand workers, zero to few thousand males (drones), depending on the time of year, and a single queen, the mother of the colony. Workers typically live 3-6 weeks during the spring and summer and can live about 4months during the winter. Queens are longer lived. Anecdotes of queens living 2-3years are not unusual, though they normally live less than a year in commercial hives. Little is known about the life span of drones. Queens develop from fertilized eggs that are not different from the eggs that develop into workers. Queens are, however, twice as large, have specialized anatomy, live much longer, and develop faster from egg to adult. All of these differences are derived from differences in larval rearing environment, primarily nutrition. The developmental trajectory of a female larva from worker into a queen can be determined as late as the third day of larval development, after this time the developmental pathway is fixed for a worker phenotype. The total time of larval development is only 5-6 days, therefore, just 2-3 days of differential feeding can lead to profound differences in development, and longevity. Workers undergo age development after they become adults. Workers usually initiate foraging behavior when they are 2-3 weeks old. The age at which a worker initiates foraging is a strong determinant of her length of life. This is presumed to be a result of the hazards of foraging, but natural senescence also occurs. Some bees remain in the nest and are never observed to forage, thereby outliving their forager sisters. Corresponding to this behavioral development are changes in the sizes of glands and the production of glandular products, increases in biogenic amine titers within the brain, an increase in the volume of specific regions of the brain, and changes in the neural system that affect perception of stimuli, and learning and memory. These age-related changes in behavior are regulated by intrinsic and extrinsic factors. Genetic variation has been demonstrated for many of these life history and behavioral traits. Selection and genome mapping studies have demonstrated relationships between the neural system, behavior, and life history traits.

Aging↗
PubMed1994

Cardiac noradrenaline in experimental rat envenomation with Africanized bee venom.

The concentration of cardiac tissue noradrenaline (NOR) was determined in Wistar rats injected with 1.5 microliters/100 g body weight Africanized bee venom (ABV) (LD50 = 0.8 microliter/100 g body weight by the intravenous route). The animals were injected with ABV by the intramuscular (IM), intraperitoneal (IP), subcutaneous (SC) and intravenous (IV) routes. Animals injected by the IM, IP and SC routes were sacrificed 4, 7 and 24 hours after injection. The animals injected by the IV route were sacrificed when they became apnoeic (within minutes). NOR levels in animals injected by the IM, IP and SC routes were inconstant and inconclusive. In contrast, animals injected with ABV by the IV route showed a significant decrease in NOR concentration when compared to their respective controls, suggesting tissue NOR release. It is suggested that the mechanism of death of the animals injected IV with ABV seems to be related, at least in part, to functional cardiac alterations secondary to stress-induced NOR release. As a consequence, cardiological monitoring of patients who are victims of multiple bee stings is recommended, together with a judicious evaluation of therapy involving drugs with a sympathomimetic action.

Animals↗