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PubMed1976

Physical, chemical, and enzymatic studies on the major sucrase of honey bees (Apis mellifera).

A sucrase from honey bees (Apis mellifera) which precipitates between ammonium sulfate saturations of 50 and 70% (5 mg protein per millilitre) and which makes up the major portion of the sucrases of honey bees was purified to homogeneity as shown by several criteria. A large part of the sucrase was found in the head while most of the rest was in the abdomen (a small amount was in the thorax). The enzyme precipitated between the same values of ammonium sulfate saturation as did the sucrase in honey and honey sucrase exhibited kinetics very similar to those of this enzyme. The enzyme was found to be a relatively nonspecific alpha-glucosidase and was shown to have transglucosidase activity. The production of glucose from sucrose was rectilinear when plotted by the Hofstee method at low substrate concentrations but decreased at high sucrose concentrations. The production of fructose was rectilinear throughout the concentration range used. The production of both glucose and rho-nitrophenol when rho nitrophenyl alpha-D-glucoside was the substrate was linear by the Hofstee plot. These effects were found to be due to transglucolysis and a mechanism of action is proposed. Amino acid and amino sugar analyses indicated that the sucrase was a glycoprotein. The molecular weight was found to be between 51000 and 82000 by three different methods and an so20.w value of 4.0 S was obtained. There was no evidence for subunit structure. Tests of the enzyme under various denaturation conditions did not reveal any unusual stabilities. The sucrase bound very tightly to a hydrophobic column. Iodoacetic acid decreased the activity of the sucrase but a large concentration was needed to bring about a 50% activity loss. Reducing agents caused some activity declines. Diethyl pyrocarbonate activated the enzyme.

Amino Acids↗
PubMed2006

Regulation of human T helper cell differentiation by antigen-presenting cells: the bee venom phospholipase A2 model.

Whereas some individuals develop immunity to bee sting and mount protective IgG4- mediated antibody responses to bee venom phospholipase A2 (PLA), others produce large amounts of PLA-specific IgE antibodies and become allergic to this, otherwise, innocuous antigen. PLA-specific IgE responses are the result of imbalanced T helper (Th)2-cell differentiation. There are multiple mechanisms driving the differentiation of naive CD4+ T cells into Th1- or Th2-cell phenotypes. Most of them are linked to the conditions occurring during initial or repeated encounters with the allergen, in the context of an antigen-presenting cell (APC). The different types of APC and their availability to display particular cytokine production profiles, pattern recognition receptors, costimulatory molecules and specific HLA haplotypes are key determinants for human Th1- and Th2-cell polarization.

Animals↗
PubMed1997

Renal changes induced by envenomation with Africanized bee venom in female Wistar rats.

Human envenomation caused by bee or wasp stings has been reported to cause acute renal failure (ARF), usually due to acute tubular necrosis (ATN), as a frequent complication. The pathogenetic mechanisms of ATN occurring in these accidents are still unclear. In the present study, female Wistar rats weighing 150-200 g were injected intravenously with Africanized bee venom at a dose of 0.4 microl/100 g body weight and used in functional and light microscopy studies. The animals were divided into two groups: the early group was studied 3-8 h after inoculation, and the late group was studied 24-30 h thereafter. The animals showed ARF characterized by reduction of glomerular filtration rate with increasing levels of plasma creatinine. They also showed increased fractional sodium and potassium excretions, suggesting changes in the proximal portion of the nephron. The water transport through collecting tubules was reduced, with consequent diuresis, indicating functional changes in the distal portion of the nephron. These functional changes were more marked in the early group, with recovery tending to occur after 24 h. Albuminuria was also observed in this group. Light microscopy showed ATN mainly in cortex and outer medulla, with isolated necrosis in cells or small groups of cells and cast formation in the distal and collecting tubules. After 24 h frequent mitotic figures were found in the tubular epithelium. The observed ARF was due to ATN which in turn was probably caused by multiple effects, mainly hemodynamic changes secondary to cardiotoxicity and systemic vasodilation caused by the venom, myohemoglobinuria, and the direct action of the venom on tubular cells.

Acute Kidney Injury↗
PubMed1985

Isotypic and idiotypic characterization of anti-bee venom phospholipase A2 antibodies.

It was shown that anti-bee venom phospholipase A2 antibodies (anti-PLA) of bee keepers belong mainly to the IgG4 class. Furthermore anti-PLA of different individuals are idiotypically related to each other. This was shown by the binding of heterologous antiidiotypic antibodies, produced against anti-PLA IgG from single donors, to anti-PLA F(ab')2 of different individuals. Therefore, the anti-PLA response provides a human model to study the idiotypic regulation of isotypes in a defined system.

Antibodies↗
PubMed1985

The role of IgG4 as blocking antibodies in asthmatics and in bee keepers.

Sera from 40 asthmatic patients and from 77 bee keepers were evaluated by solid-phase radioimmunoassay for their allergen-specific IgG4 antibody levels. The results indicated that allergen-specific IgG4 antibodies become prominent upon repeated parenteral stimulation with antigen, i.e. immunotherapy and bee stings, and suggested the possible association of IgG4 with blocking antibodies in these allergic conditions.

Allergens↗
PubMed2004

The use of Open Reading frame ESTs (ORESTES) for analysis of the honey bee transcriptome.

BACKGROUND: The ongoing efforts to sequence the honey bee genome require additional initiatives to define its transcriptome. Towards this end, we employed the Open Reading frame ESTs (ORESTES) strategy to generate profiles for the life cycle of Apis mellifera workers. RESULTS: Of the 5,021 ORESTES, 35.2% matched with previously deposited Apis ESTs. The analysis of the remaining sequences defined a set of putative orthologs whose majority had their best-match hits with Anopheles and Drosophila genes. CAP3 assembly of the Apis ORESTES with the already existing 15,500 Apis ESTs generated 3,408 contigs. BLASTX comparison of these contigs with protein sets of organisms representing distinct phylogenetic clades revealed a total of 1,629 contigs that Apis mellifera shares with different taxa. Most (41%) represent genes that are in common to all taxa, another 21% are shared between metazoans (Bilateria), and 16% are shared only within the Insecta clade. A set of 23 putative genes presented a best match with human genes, many of which encode factors related to cell signaling/signal transduction. 1,779 contigs (52%) did not match any known sequence. Applying a correction factor deduced from a parallel analysis performed with Drosophila melanogaster ORESTES, we estimate that approximately half of these no-match ESTs contigs (22%) should represent Apis-specific genes. CONCLUSIONS: The versatile and cost-efficient ORESTES approach produced minilibraries for honey bee life cycle stages. Such information on central gene regions contributes to genome annotation and also lends itself to cross-transcriptome comparisons to reveal evolutionary trends in insect genomes.

Animals↗
PubMed2006

Deformed wing virus is not related to honey bees' aggressiveness.

Guards of Cyprian honey bee colonies, Apis mellifera cypria, display a great defensive behaviour against hornets' attacks. The deformed wing virus (DWV) and the kakugo virus (KV) genomes are very similar, but unlike KV, the presence of DWV is not related to honey bees' aggressiveness. This discrepancy is further discussed.

Aggression↗
PubMed2006

Getting a buzz out of the bee genome.

The honey bee Apis mellifera displays the most complex behavior of any insect. This, and its utility to humans, makes it a fascinating object of study for biologists. Such studies are now further enabled by the release of the honey-bee genome sequence.

Animals↗
PubMed2003

Effects of load type (pollen or nectar) and load mass on hovering metabolic rate and mechanical power output in the honey bee Apis mellifera.

In this study we tested the effect of pollen and nectar loading on metabolic rate (in mW) and wingbeat frequency during hovering, and also examined the effect of pollen loading on wing kinematics and mechanical power output. Pollen foragers had hovering metabolic rates approximately 10% higher than nectar foragers, regardless of the amount of load carried. Pollen foragers also had a more horizontal body position and higher inclination of stroke plane than measured previously for honey bees (probably nectar foragers). Thorax temperatures ranked pollen > nectar > water foragers, and higher flight metabolic rate could explain the higher thorax temperature of pollen foragers. Load mass did not affect hovering metabolic rate or wingbeat frequency in a regression-model experiment. However, using an analysis of variance (ANOVA) design, loaded pollen and nectar foragers (mean loads 27% and 40% of body mass, respectively) significantly increased metabolic rate by 6%. Mean pollen loads of 18% of body mass had no effect on wingbeat frequency, stroke amplitude, body angle or inclination of stroke plane, but increased the calculated mechanical power output by 16-18% (depending on the method of estimating drag). A rise in lift coefficient as bees carry loads without increasing wingbeat frequency or stroke amplitude (and only minimal increases in metabolic rate) suggests an increased use of unsteady power-generating mechanisms.

Animals↗
PubMed2005

Allometric scaling of flight energetics in Panamanian orchid bees: a comparative phylogenetic approach.

The relationship between body size and flight energetics was studied in the clade of tropical orchid bees, in order to investigate energy metabolism and evolution. Body mass, which varied from 47 to 1065 mg, was found to strongly affect hovering flight mass-specific metabolic rates, which ranged from 114 ml CO(2) h(-1) g(-1) in small species to 37 ml CO(2) h(-1) g(-1) in large species. Similar variation of wingbeat frequency in hovering flight occurred among small to large species, and ranged from 250 to 86 Hz. The direct relationship between such traits was studied by the comparative method of phylogenetically independent contrasts (PIC), using a new molecular phylogeny generated from the cytochrome b gene partial sequences. We found wingbeat frequency variation is satisfactorily explained by variation in wing loading, after corrections for body mass and phylogeny. The correlated evolution of mass-specific metabolic rate, wingbeat frequency and wing loading was also revealed after correcting for phylogeny and body mass. Further, the effect of body size on flight energetics can be understood in terms of a relationship between wing form and kinematics, which directly influence and explain the scaling of metabolic rate in this group of bees.

Animals↗
PubMed2005

Effect of food quality, distance and height on thoracic temperature in the stingless bee Melipona panamica.

Stingless bees (Apidae, Meliponini) can recruit nestmates to good food sources. We present the first data showing that recruiting meliponine foragers at feeders and inside nests regulate their thoracic temperature according to net food profitability. Using infrared thermography, we found that Melipona panamica foragers elevated their thoracic temperature at profitable food sources (higher sucrose concentration, closer to the nest). At food sources, there is an increase of approximately 0.9 degrees C in thoracic temperature (Tth) per 1 mol l(-1) increase in sucrose concentration (at 20 m distance from nest: 1 mol l(-1) sucrose concentration, Tth=36.6+/-0.8 degrees C, T(a)=31.3+/-0.5 degrees C; 2.5 mol l(-1) sucrose concentration, Tth=36.9+/-0.6 degrees C, Ta=29.9+/-0.2 degrees C). Inside the nest, the difference between thoracic temperature Tth and ambient air temperature Ta (DeltaTnest) decreases by 0.4 degrees C with each 100 m increase in feeder-to-nest distance and increases by 0.1 degrees C per 1 mol l(-1) increase in sucrose concentration. The Tth of returning foragers was significantly higher at all tested sucrose concentrations (1.0-2.5 mol l(-1) sucrose concentration) and distances (25-437 m) as compared to Ta (at 2.5 mol l(-1) sucrose concentration: 25 m distance from nest, intranidal Tth=30.2+/-1.3 degrees C, Ta=24.8+/-0.7 degrees C; 437 m distance from nest, intranidal Tth=28.6+/-1.7 degrees C, Tnest=25.4+/-1.4 degrees C). For highly profitable food sources (2.5 mol l(-1) sucrose concentration and < or =100 m from the nest), forager Tth was slightly higher than that of randomly chosen control bees inside the nest.

Animal Communication↗
PubMed2005

Look and turn: landmark-based goal navigation in honey bees.

This report describes the piloting mechanisms employed by honey bees during their final approach to a goal. Conceptually applying a bottom-up approach, we systematically varied the position, number and appearance landmarks associated with a rewarded target location within a large, homogenous flight tent. The flight behavior measured under various conditions is well explained with visuo-motor control loops that link perceived landmarks with appropriate turning responses. This view is consistent with the requirement of prolonged reinforcement learning for efficient goal navigation. A simple model is able to provide a comprehensive explanation for diverse flight patterns that range from convoluted searching behavior to highly idiosyncratic approaches, depending on the experimental context. Our results challenge the prevalent notion that honey bees employ image matching for visual guidance toward a goal site. Basic visuo-motor control loops may better meet the high demands for robust and fast flight control, which could serve as a powerful bio-mimetic design principle for micro-robotic aircraft.

Animals↗
PubMed2006

Mechanics of nectar feeding in the orchid bee Euglossa imperialis: pressure, viscosity and flow.

The orchid bee Euglossa imperialis sucks nectars through a slender proboscis. I tested how nectar properties influence this suction pressure and whether ambient air pressure sets the upper limit for suction feeding. Nectar intake rate was measured as a function of sucrose concentration (5-75% w/w), nectar viscosity (2-80 mPa s), and ambient pressure (101-40 kPa). Intake rate declines from about 1.2 mul s(-1) to 0.003 mul s(-1) as sucrose concentration increases from 15% to 65% sucrose. When sucrose concentration is held at 25% while viscosity increases from 2 to 80 mPa s, intake rate declines. When viscosity is held at 10.2 mPa s (the viscosity of 50% sucrose) while sucrose concentration increases from 5% to 50%, intake rate remains constant. Intake rate was limited by a reduction in ambient pressure at all nectar concentrations. Assuming a rigid proboscis, the Hagen-Poiseuille equation suggests that suction pressure increases with viscosity from 10 kPa at 5% sucrose to 45 kPa at 65% sucrose. However, because intake rate declined by the same fraction under hypobaria (40 kPa) at all sucrose concentrations, the euglossine bee proboscis may be better described as a collapsible tube: expanding or collapsing depending on the flow rate, the pressure gradient along the proboscis, and circumferential forces imposed by the proboscis walls.

Animals↗
PubMed2001

Limits to the salience of ultraviolet: lessons from colour vision in bees and birds.

Ultraviolet is an important component of the photic environment. It is used by a wide variety of animals and plants in mutualistic communication, especially in insect and flower inter-relationships. Ultraviolet reflections and sensitivity are also becoming well considered in the relationships between vertebrates and their environment. The relative importance of ultraviolet vis à vis other primary colours in trichromatic or tetrachromatic colour spaces is discussed, and it is concluded that ultraviolet is, in most cases, no more important that blue, green or red reflections. Some animals may use specific wavebands of light for specific reactions, such as ultraviolet in escape or in the detection of polarised light, and other wavebands in stimulating feeding, oviposition or mating. When colour vision and, thus, the input from more than a single spectral receptor type are concerned, we point out that even basic predictions of signal conspicuousness require knowledge of the neuronal wiring used to evaluate the signals from all receptor types, including the ultraviolet. Evolutionary analyses suggest that, at least in arthropods, ultraviolet sensitivity is phylogenetically ancient and undergoes comparatively little evolutionary fine-tuning. Increasing amounts of ultraviolet in the photic environment, as caused by the decline of ozone in the atmosphere, are not likely to affect colour vision. However, a case for which ultraviolet is possibly unique is in the colour constancy of bees. Theoretical models predict that bees will perform poorly at identifying pure ultraviolet signals under conditions of changing illumination, which may explain the near absence of pure ultraviolet-reflecting flowers in nature.

Animals↗
PubMed1976

Activities of antennal and ocellar interneurones in the protocerebrum of the honey-bee.

1. Unit responses to olfactory and mechanical stimuli of the antennae, and illumination of the ocelli, were recorded extracellularly in the protocerebrum of the honey-bee. 2. Bimodal units responded both to antennal and to ocellar stimuli; antennal units responded to the former and the ocellar units to the latter. Some antennal units responded to olfactory stimuli (olfactory units), and others responded to mechanical stimuli (mechanical units). 3. Ocellar units in the brain showed phasic responses at the start and/or cessation of illumination. Six types of responses were found. 4. About two-thirds of the bimodal units showed the same type of response to stimulation of the antennae as to stimulation of the ocelli. Most of them showed excitation by each stimulus. 5. Bimodal units were distributed around the alpha-lobe in the protocerebral lobe, whereas the antennal and the ocellar units were widely distributed. 6. By turning off the ocellar illumination, background discharge frequency, and the pattern and magnitude of responses to antennal stimuli, were changed. The activities of the ocellar units were altered by inputs from the antenna. 7. It was postulated that antennal and ocellar inputs converge and interact with each other in the protocerebral lobe of the honey-bee.

Action Potentials↗
PubMed2005

Two related cinnamic Acid derivatives from Brazilian honey bee propolis, baccharin and drupanin, induce growth inhibition in allografted sarcoma S-180 in mice.

Honey bee propolis is rich in cinnamic acid derivatives. Baccharin and drupanin from Brazilian honey bee propolis are cinnamic acid derivatives that contain prenyl moieties. We previously isolated these two compounds and demonstrated that they induce an apoptotic event in several tumor cell lines. In this study, we examined the tumoricidal activity of baccharin and drupanin in mice allografted with sarcoma S-180 and also studied the genotoxic effects on normal splenocytes using the alkaline single cell gel (comet) assay. We found that both baccharin and drupanin effectively suppressed growth of the tumor. Furthermore, these compounds induced a significant genotoxic effect on the tumor cells in comparison with normal splenocytes. Thus, baccharin and drupanin are potent tumor suppressive components of honeybee propolis.

Animals↗
PubMedDate not supplied

Analysis of the labial gland secretions of the male bumble bee Bombus perplexus Cresson (Hymenoptera: Apidae) from North America.

The labial gland secretions from males of the bumble bee Bombus (Pyrobombus) perplexus Cresson were analysed by gas chromatography/mass spectrometry (GC/MS) in the electron impact and positive ion chemical ionization mode. The major compound of the complex mixture of alkenols, alkenals, fatty acids, hydrocarbons, wax type esters and steroids is 3,7,11,15-tetramethyl-2,6,10-hexadecatrien-1-ol (geranylcitronellol), considerable amounts of hexadecan-1-ol and Z-9-hexadecen-1-ol were also found. All alcohols were present as esters of the detected acids. In older samples both the acids and the alcohols sometimes could not be detected in the GC; therefore, the possibility to check the detected acid-alcohol pattern by interpreting the wax type ester peaks is very instructive. Moreover, the labial gland contains a rich mixture of mono- and di-unsaturated straight chain hydrocarbons. The similarity in composition of the labial glands of the North American B. (Pyrobombus) perplexus with the Eurasian species B. (Pyrobombus) hypnorum corroborates the assumption that the two species are conspecific. The likely supposition that the hydrocarbons could play an essential role in the chemical communication in bumble bees is discussed.

Alcohols↗
PubMedDate not supplied

Antioxidant activity and angiotensin I-converting enzyme inhibition by enzymatic hydrolysates from bee bread.

Enzymatic hydrolysates were prepared from bee bread using three proteases. The antioxidant properties of these hydrolysates were measured using four different methods. These had remarkable antioxidant activity similar or superior to that of 1 mM alpha-tocopherol. They also had high scavenging activities against active oxygen species as the superoxide anion radical and hydroxyl radicals. Moreover, they showed angiotensin I-converting enzyme inhibitory activities and the activities were similar to those from various fermented foods such as fish sauce, sake, vinegar, cheese, miso, and natto. The present studies reveal that enzymatic hydrolysates from bee bread are of benefit not only for the materials of health food diets, but also for in patients undergoing various diseases such as cancer, cardiovascular diseases, diabetes, and hypertension.

Angiotensin-Converting Enzyme Inhibitors↗