Chemical composition of the dufour gland secretion in queens of Melipona bicolor (Hymenoptera, Meliponini)

We describe differences in the chemical composition of the Dufour gland secretion of virgin and physogastric queens of Melipona bicolor through gas chromatography and mass spectrometry. The Dufour gland secretion of virgin queens consists only of hydrocarbons, while that of physogastric queens contains, besides these, a variety of other compounds, such as isobutyrate and acetate esters. Such differences may indicate the queen fecundity condition and the oxygenated compounds of the physogastrics secretion may help to increase their attractiveness.

Macromolecular array patterns of silk gland secretion in social Hymenoptera larvae

The cocoon, produced by most holometabolous insects, is built with silk that is usually produced by the larval salivary gland. Although this silk has been widely studied in the Lepidoptera, its composition and macromolecular arrangement remains unknown in the Hymenoptera. The macromolecular array patterns of the silk in the larval salivary gland of some meliponids, wasps, and ants were analyzed with polarized-light microscopy, and they were compared with those of Bombyx mori (Lepidoptera). There is a birefringent secretion in the glandular lumen of all larvae, due to filamentous structural proteins that display anisotropy. The silk in the distal, middle and proximal regions of the secretory portion of Formicidae and Vespidae glands presented a lattice optical pattern. We found a different pattern in the middle secretory portion of the Meliponini, with a zigzag rather than a lattice pattern. This indicates that the biopolymer fibers begin their macromolecular reorganization at this glandular region, different from the Formicidae and the Vespidae, in which the zigzag optical pattern was only found at the lateral duct. Probably, the mechanism of silk production in the Hymenoptera is a characteristic inherited from a common ancestor of Vespoidea and Sphecoidea; the alterations in the pattern observed in the Meliponini could be a derived characteristic in the Hymenoptera. We found no similarity in the macromolecular reorganization patterns of the silk between the Hymenoptera species and the silkworm.

Enzymatic variability among venoms from different subspecies of Apis mellifera (Hymenoptera: Apidae)

The enzymatic variability was analyzed in venom extracts from bees reared in different colonies of the Africanized, A. m. ligustica and A. m. carnica subspecies. The implications of this variation focused on the biochemistry differentiation and immunogenicity of these venoms. The results showed the existence of a huge variability among the subspecies as well as among the colonies for three out of the six tested components - hyaluronidase, acid phosphatase and proteases - suggesting the utilization of these features as possible biochemical markers. Furthermore, although not statistically significant, it was found that the Africanized bee venom presented slightly higher levels of protein content and esterase activity, when compared to the other subspecies. If the esterase plays a role in the pain intensity caused by the sting, as suggested elsewhere, this might suggest a reason for a bigger algogenicity of this venom in relation to that of European bees. On the other hand, A. m. ligustica bees presented the highest levels of proteolytic and acid phosphatase activities, whose functions are not enlightened in Hymenoptera venoms. The A. m. carnica workers presented the highest hyaluronidase and the lowest acid phosphatase activity levels. The extremely variable results among colonies of the same subspecies and among subspecies, for the tested venom components, justify the absence of correlation between allergic reactions and tests with pooled venom.

Ultramorphology and histology of the venom gland of workers of Apis mellifera (Hymenoptera, Apidae) before and after an electrical shock treatment

This paper describes the ultramorphology and histology of the venom reservoir in 14-day old workers of Apis mellifera, immediately before and after the application of electrical shocks with the object of causing venom elimination and reservoir collapse. The external epithelial surface of the reservoir was differentiated according to its morphological aspects into posterior, median, and proximal or duct regions at the ventral surface and into anterior and posterior regions at the dorsal surface. While the epithelium of the proximal region forms a ventral infolding, a dorsal salience is formed at this region. These structures and the epithelial regions persist both in full and empty reservoirs. The reservoir appeared full and distended before the electrical shocks were applied and became empty and withered afterwards due to the elimination of the secretion, without any reductions in length. Nevertheless, some secretion was kept inside the lumen, thus suggesting a possible role for the reservoir in the modification of the secretion.

Hydrolases in the hypopharyngeal glands of workers of Scaptotrigona postica and Apis mellifera (Hymenoptera, Apinae)

Hydrolytic enzymes from hypopharyngeal gland extracts of newly emerged, nurse and foraging workers of two eusocial bees, Scaptotrigona postica, a native Brazilian stingless bee, and the Africanized honey bee (Apis mellifera) in Brazil, were compared. The hypopharyngeal gland is rich in enzymes in both species. Fifteen different enzymes were found in the extracts, with only a few quantitative differences between the species. Some of the enzymes present in the extracts may have intracellular functions, while others seem to be digestive enzymes. Scaptotrigona postica, had lower β-glucosidase and higher lipase esterase activities than A. mellifera. The differences may be due to different feeding habits and behavioral peculiarities of the two species. ©FUNPEC-RP.

Africanized honeybees: Biological characteristics, urban nesting behavior and accidents caused in Brazilian cities (Hymenoptera: Apidae)

In 1956 African honeybee queens (Apis mellifera scutellata) were imported from South Africa and Tanzania to Brazil, as part of a government project to increase Brazilian honey production. The European honeybees existing in that country had not adapted well to the tropical conditions and consequently, had a low productivity. The newly introduced bee was known to produce substantially more honey than the other subspecies, but was also famous for its great aggressiveness and quicker attack of intruders with less disturbance. Hoping to create a new hybrid bee that would be both docile and productive, the scientist Warwick Estevam Kerr tried to cross the African and the European subspecies under controlled conditions. However, an accident resulted in the escape of 26 swarms into the Brazilian countryside, where their queens mated with drones of the European resident honeybees. The poly-hybrid bees resulting from these crossings expressed scutellata-like reproductive, foraging, and defensive behaviors and, for this reason, were called Africanized honeybees. They spread rapidly from the introduction area of the African honeybees (near Rio Claro, São Paulo state) to as far south as mid-Argentina and to the north of Texas, also settling in Arizona, New Mexico, California and Nevada, due to their high adaptability to variable ecological conditions. In spite of a few undesirable behaviors, these bees have been invoking larger economic interest because they produce much more honey, have good resistance to diseases and are excellent pollinators. In Brazil, because people frequently disturb the environment, the occupation of urban refuges by Africanized honeybees has been increasing in the last years. The concern with accidents is generally associated with the high swarming frequency recorded during the year and the variety of shelters available in urban areas. This paper deals with the biological characteristics of the Africanized honeybees, their nesting behavior in urban environments, and accidents caused by these bees in Brazilian cities.

Influence of the collection methodology on the Apis mellifera venom composition: Peptide analysis

Differences of venom peptide composition as function of two collection methodologies, electrical stimulation (ES) and reservoir disruption (RD), were analyzed by reverse-phase HPLC in Apis mellifera races - A. m. adansonii, A. m. ligustica and Africanized honeybee. The analyses were performed through determination of the relative number and percentage of each molecular form associated to the peaks eluted by chromatography. Comparison of these profiles revealed qualitative and quantitative differences related to the venom collection methodology as well to the three races analyzed. In contrast to data usually found for venom proteins, the three races presented a major number of peaks or molecular forms when venom was collected by ES. Besides, in general, the relative concentration of each peak was higher for ES in relation to RD. That indicates the presence of molecular precursors in the venom obtained by RD. The presence/absence pattern of the peaks, such as their relative concentrations showed a closer similarity between A. m. adansonii and the Africanized honeybees than that observed between these and A. m. ligustica. The obtained data allowed a discussion about the differences in the relative concentration of each venom component according to the collection methodology, and finally the biological action of the venom in different races. So, these results, apart from being useful to establish a peptide profile for each bee race as a function of the venom collection methodology, pointed out once more that the chromatographic techniques are a great tool for the identification of A. mellifera subspecies.

Histologia do rim, fígado e intestino de girinos de rã-touro (Rana catesbeiana) alimentados com dietas contendo própolis

This research was aimed at verifying the occurrence of possible alterations in liver, kidney and intestine of bullfrog tadpoles in stage 42 fed with diets containing different concentrations (0.0; 0.2; 0.5; 1.0 and 1.5%) of propolis hydroalcoholic extract. The experiment was carried out in laboratory of Aquatic Organisms Nutrition from Aquaculture Center of UNESP, where 1,400 tadpoles in stage 26 were used and distributed in twenty experimental aquariums. In the end of experiment (60 days) three tadpoles from each repetition were sacrificed and kidney, liver and intestine samples were collected to processing of histological slices in Histology's Laboratory pertaining to Department of Morphology and Physiology from FCAV - UNESP. Samples were fixed, dehydrated, stained in HE, analysed, photomicrographed and thickness of intestinal epithelium was measured. Histological disturbances in tadpoles's intestine, kidneys and liver were not observed. Thickness of intestinal epithelium from the same ones was not influenced (P>0.05) by propolis concentrations.

Éster de sacarose no controle do Varroa estructor em abelhas africanizadas

This study aimed to determine the effect of sucrose ester on the control of Varroa destructor mite infestation in Africanized honeybees. For the in vitro experiments, the product was tested in bees and mites at five concentrations obtained through dilution in water (T0: 100% distilled water; T1: 0.5%; T2: 1%; T3: 2%; T4: 5%; and T5: 10% sucrose ester).For the field studies, the experimental design was completely randomized, with four treatments and seven replicates, totaling 28 colonies, from which seven were the controls, seven were treated with 0.1% sucrose ester, seven with 0.2% sucrose ester, and seven hives with 0.5% sucrose ester diluted in water. In the in vitro study, the sucrose ester at 0.5% concentration caused mite and bee mortality. In the field tests, the product at 0.2% concentration reduced Varroa destructor infestation in Africanized honeybees and, therefore, may be used as a tool to control this pest. At 0.1, 0.2, and 0.5% concentrations, sucrose ester did not impair the establishment of open and capped brood areas, as well as stored food areas in the hive, suggesting it is not toxic to Africanized honeybees.

Propriedade físico-química da própolis em função da sazonalidade e método de produção

The aim of this work was to investigate monthly, for one year the seasonality effect on the physicochemical properties (dry weight, flavonoids contents, pH and antioxidant activity) of ethanolic extract (EAP) of propolis produced by three different techniques (intelligent propolis collector, plastic screen or scraping) fifteen colonies of africanized bees. No differences (p>0.05) in the physicochemical properties due to the technique of propolis production and seasonality were observed.

Network node with wireless and wired interfaces: Nios II processor and uClinux to development of a NCAP embedded (IEEE 1451.1) with two interfaces, wireless (IEEE 1451.5) and wired (IEEE p1451.2)

This paper presents a NCAP embedded on DE2 kit with Nios II processor and uClinux to development of a network gateway with two interfaces, wireless (ZigBee) and wired (RS232) based on IEEE 1451. Both the communications, wireless and wired, were developed to be point-to-point and working with the same protocols, based on IEEE 1451.0-2007. The tests were made using a microcomputer, which through of browser was possible access the web page stored in the DE2 kit and send commands of control and monitoring to both TIMs (WTIM and STIM). The system describes a different form of development of the NCAP node to be applied in different environments with wired or wireless in the same node. © 2011 IEEE.

Chemometric analysis of Hymenoptera toxins and defensins: A model for predicting the biological activity of novel peptides from venoms and hemolymph

When searching for prospective novel peptides, it is difficult to determine the biological activity of a peptide based only on its sequence. The trial and error approach is generally laborious, expensive and time consuming due to the large number of different experimental setups required to cover a reasonable number of biological assays. To simulate a virtual model for Hymenoptera insects, 166 peptides were selected from the venoms and hemolymphs of wasps, bees and ants and applied to a mathematical model of multivariate analysis, with nine different chemometric components: GRAVY, aliphaticity index, number of disulfide bonds, total residues, net charge, pI value, Boman index, percentage of alpha helix, and flexibility prediction. Principal component analysis (PCA) with non-linear iterative projections by alternating least-squares (NIPALS) algorithm was performed, without including any information about the biological activity of the peptides. This analysis permitted the grouping of peptides in a way that strongly correlated to the biological function of the peptides. Six different groupings were observed, which seemed to correspond to the following groups: chemotactic peptides, mastoparans, tachykinins, kinins, antibiotic peptides, and a group of long peptides with one or two disulfide bonds and with biological activities that are not yet clearly defined. The partial overlap between the mastoparans group and the chemotactic peptides, tachykinins, kinins and antibiotic peptides in the PCA score plot may be used to explain the frequent reports in the literature about the multifunctionality of some of these peptides. The mathematical model used in the present investigation can be used to predict the biological activities of novel peptides in this system, and it may also be easily applied to other biological systems. © 2011 Elsevier Inc.

Development of heterogeneous node network using microcontroller with protocols CAN and Zigbee

In this paper was proposed the development of an heterogeneous system using the microcontroller (AT90CANI28) where the protocol model CAN and the standard IEEE 802.15.4 are connected. This module is able to manage and monitor sensors and actuators using CAN and, through the wireless standard 802.15.4, communicate with the other network modules. © 2011 IEEE.

Atividade viral do vírus respiratório sincicial bovino (brsv) em bezerros leiteiros

The purpose of the present study was to evaluate the antimicrobial activity of propolis extracts diluted in different solvents against bacteria from Staphylococcus genus. The study was performed in the Immunology and Microbiology Laboratory from Universidade Federal do Vale do São Francisco. The propolis extracts were prepared using brown propolis diluted in different solvents such as chloroform, methanol, ethyl acetate and grain alcohol. In order to determine the antimicrobial potential of extracts, agar well diffusion method was used, with controls for each diluent. After that, Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) methods were used. All tests were performed in triplicate. In the agar well diffusion test, the measurements of the inhibition zone for propolis extract were as follows: grain alcohol and propolis (2.88mm), methanol and propolis (2.41mm), chloroform and propolis (2.40mm) and ethyl acetate and propolis (0.83mm). The MBC of propolis extracts in different solvents were 93.75 μg/mL for grain alcohol, 375 μg/mL for chloroform and methanol and 3,000 μg/ml for ethyl acetate. Statistically significant differences were achieved comparing the inhibition zones of propolis diluted in grain alcohol and ethyl acetate (2.88 and 0.83 mm, respectively). Considering the low cost of therapy and the activity of the propolis against caprine mastitis pathogens, other studies regarding in vivo activity and chemical characterization are necessary, in addition to evaluation of the toxicological aspects of propolis extracts.

Extrato de própolis no controle de helmintoses em bezerros

The use of conventional anthelmintic has been a growing concern among consumers who have become more and stricter toward drug residues in products of animal origin. Thus, this research aimed to evaluate the anthelmintic effect of alcoholic extract of propolis, at 30% of concentration, in naturally infected calves. Twelve calves weighting 60 kg and aging 90 days old were used. The treatments were performed by direct oral administration of 10 mL of EAP. The calves received the extract at every 8 h intervals, for five consecutive days. The results were evaluated comprising the detection of light and heavy eggs counted per gram of feces (EPG), immediately before and after treatment, calculating the percentage of reduction. For the statistical analysis, the results were evaluated by Wilcoxon unilateral test of signed points at 5% probability. Trichostrongylus sp. and Strongyloides sp. were found. After treatment, 83% of animals showed an average decrease of 48.48% per counting of EPG. Therefore, propolis may represent an important adjunctive therapy to control helminthiasis in cattle. It was particularly important in ecological organic and biological-dynamic systems of production, whose use of chemicals is prohibitive and limiting factor for certification.