Orientador: Flávio Luis Schmidt / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-19T16:23:54Z (GMT). No. of bitstreams: 1 Vieira_LuanaReis_M.pdf: 12427431 bytes, checksum: 43cbcc66f7d6f2b06d12185e0be5c71d (MD5) Previous issue date: 2012 / Resumo: O mel pode ser definido como uma solução concentrada de açúcares. Possui enzimas,ácidos orgânicos e outros compostos. O aquecimento do mel é usualmente utilizado para descristalizar e facilitar o processamento. Atualmente na indústria o mel é aquecido por convecção forçada de ar e pode demorar de 4 a 7 dias, onerando o processamento. O emprego de altas temperaturas no mel pode alterar muitas de suas propriedades, como diminuição da enzima diastase e aumento do hidroximetilfurfural (HMF), importantes indicadores de qualidade. O objetivo do trabalho foi estudar o processo de descristalização do mel frente ao tratamento térmico em banho de água sob agitação,visando desenvolver métodos mais eficientes para a descristalização do produto. A partir dos dados da história térmica do mel, os parâmetros cinéticos de transferência de calor e os impactos do aquecimento nas propriedades do mel foram verificados. Foram utilizados três tipos de méis para avaliação de suas propriedades sob influência do aquecimento e determinação das cinéticas de reação. Avaliaram-se as alterações no pH, acidez, índice de formol e cor, além da atividade diastásica e conteúdo de HMF formados nas temperaturas de 50, 70 e 90ºC. Para os estudos de descristalização foram realizados 12 ensaios utilizando-se mel de eucalipto, safra 2010, aquecido nas temperaturas de 58, 75 e 95ºC e velocidades de rotação 0, 20, 30 e 40 rpm. O aquecimento a 50 e 70ºC não produziu importantes alterações na sua composição inicial, entretanto a 90ºC as alterações começaram a se evidenciar. Os resultados obtidos demonstraram que a formação de HMF e a destruição da diastase puderam ser descritos pelo modelo cinético de primeira ordem com Ea (energia de ativação) de 19,5 kcal/mol, z (índice térmico) de 27,7ºC e Q10 (quociente de velocidade) de 2,3; para a formação do HMF e Ea de 31,4 kcal/mol, z de 17,8ºC e Q10 de 4,3 para a degradação da diastase, sendo notada a maior dependência desta com a temperatura. Foram encontrados menores valores de fh (parâmetro do efeito da temperatura) com o aumento da agitação das embalagens e também com o aumento da temperatura empregada, sendo possível a partir da cinética das reações, estimarem as concentrações finais de HMF e diastase. O ensaio com melhores resultados para a descristalização do mel foi a 75ºC e 20 rpm onde o mel apresentou-se totalmente descristalizado e sem perdas significativas da qualidade. O fh encontrado para este ensaio foi de 16 min e coeficiente de transferência de calor 54,2 W/m2.ºC. Foi possível concluir que o uso de tratamento térmico em banho sob agitação para descristalização do mel melhora as propriedades de transferência de calor reduzindo o tempo total de processo, mantém as características de qualidade do mel em níveis aceitáveis, podendo ser empregado para otimização, rapidez de fluxo, eficiência da descristalização e aumento da produtividade nas indústrias / Abstract: Honey can be defined as a concentrated solution of sugars, containing many organic acids, pigments and other compounds. Heating of honey is usually utilized to dissolve the sugar crystals, making a more acceptable product. Nowadays, at big industries, honey is heated by forced air convection, which takes 4 to 7 days. This process is quite onerous,becoming a problem on honey processing. High temperatures can change many properties of honey, like decrease in diastase activity and increase in hydroxymetylfurfural (HMF) contents, important indicators of honey¿s quality. The aim of the present work was to study the liquefying crystallized honey process using thermal treatment in water bath under stirring, in order to develop more efficient methods of doing it. The work intended to verify, based on data from the thermal history of honey, the kinetic parameters of heat transfer and the consequences of heating on honey properties. To evaluate these consequences and to determine the reaction kinetics, three kinds of honey were used. The parameters: pH, acidity, formaldehyde contents and color, besides diastase activity and HMF contents were evaluated at 50, 70 and 90oC. To study liquefying crystallized honey process only eucalyptu's honey, crop 2010, was used. It was submitted to 12 essays, using temperatures of 58, 75 and 95oC, and stirring speed of 0, 20, 30 and 40 rpm. At 50 and 70ºC the changes observed in honey properties were not important, becoming significant at 90ºC. The results obtained demonstrated that production of HMF and degradation of diastase could be described by the kinetic model of first order with Ea of 19,52 kcal/mol, z of 27,7oC and Q10 of 2,32 for HMF production and Ea de 31,4 kcal/mol, z de 17,8ºC e Q10 de 4,27 for diastase. It was noted that diastase had the great temperature dependency. Increase in temperature and stirring speed of honey container, leds to decrease in fh (parameter of temperature effect) values. The reaction kinetics provided, in addition to kinetic parameters, estimated values of final concentrations of HMF and diastase. The essay with best results for liquefy crystallized honey was that of 75oC and 20rpm, in which honey was fully liquefied with no significant loss of quality. In this essay a fh value of 16 min and a heat transfer coefficient of 54,2 W/m2.OC were found. It was possible to conclude that use of heating treatment in water bath under stirring for liquefying crystallized honey improve the heat transfer properties, reducing total processing time,keep quality characteristics of honey at acceptable levels and, therefore, can be employed at the honey processor industries for optimization, flow quickness, efficiency in liquefying crystallized honey and increase in productivity / Mestrado / Tecnologia de Alimentos / Mestre em Tecnologia de Alimentos

The role of the queen in wax secretion and comb building was studied in the the Cape honeybee, Apis mellifera capensis (Escholtz). The percentage of bees bearing wax and the amount of wax borne by these bees did not differ between the experiments. This meant that the queenless and queenright colonies had the potential to construct equal amounts of comb as the amounts of wax available for comb building was the same. Contrary to this prediction, queenright colonies constructed 8 times more comb than their queenless counterparts. Queenright Apis mellifera scutellata colonies constructed 4 times more comb than their queenless counterparts. The increased amount of 9-oxo-2-decanoic acid (90DA) in the A.m.capensis mandibular gland secretions could not alone account for this difference. In fact, A.m.capensis and A.m.scutellata colonies constructed similar amounts of comb when they were given their own queens or queens from the other race. Worker bees need to have direct contact with their queen for comb building to be enhanced. Even when the queen had her mandibular glands extirpated and tergite glands occluded large amounts of comb were constructed than when access to the queen was limited. Direct access to the head of a mated queen proved to be the stimulus enhancing comb building. No comb was constructed when the workers had access to the abdomen of the queen. Virgin queens did not stimulate comb building. The relatively large amounts of 90DA and 9HDA from the mandibular glands of Cape virgin queens had not influenced comb building. Worker sized cells were generally constructed. These cells were slightly smaller than those constructed by European honeybees, but were indicative of African bees. A few queen less colonies constructed cells that were of an intermediate drone and worker size. Four mandibular gland pneromones were measured by gas chromatography. No correlations between these pheromones and the comb construction measurements were found. It is unlikely that the mandibular gland pheromones are the only pheromones that stimulate comb building. Pheromones from other glands on the head may contribute towards the enhancement of comb building, and they are not present in virgin queens

This thesis analyzes mixtures of neem oil and amitraz as alternative control for Varroa destructor, a major pest of Apis mellifera, under different agricultural settings. In organic and conventional farms, the different treatments were applied in colonies to determine impacts on mite loss, colony strength, and honey yield. The results demonstrated neem to have the least effective control on mite mortality, while the neem and amitraz mixture had the most. Furthermore, no long term impacts on queen fecundity and colony strength were noticed between treatments. However, queen fecundity and honey yield was significantly higher in sites with higher flower abundance and diversity, demonstrating higher colony strength in these sites. Further understanding of the relationship between apiculture and agricultural management is vital for conservation of pollinator health and associated habitats.

Urease of Helicobacter pylori is an important virulence factor implicated in the pathogenesis of many clinical conditions, such as chronic gastritis, peptic ulceration, and gastric cancer. Many urease inhibitors have been discovered, like phosphorodiamidates, hydroxamic acid derivatives, and imidazoles. Despite good activities at the enzyme level and excellent kinetic properties most of them have not been used as therapeutic agents in vivo because of their side effects, toxicity and instability. This has led to much attention to focus on exploring the novel urease inhibitory activities of natural products because of their low toxicity and good bioavailability. Honey, a natural product has been used in folk medicine due to its antitumor, antioxidant, antimicrobial and anti-inflammatory properties. The aims of this study were to isolate, characterise, purify urease produced by H. pylori and investigate the inhibitory effects of solvent honey extracts on its enzymatic activity. Urease was found to be both surface-associated and cytoplasmic. Maximum cytoplasmic urease activity was found to occur after 72 hr whereas maximum extracellular urease activities were found to occur after 96 hr. Characterization of the crude cytoplasmic urease revealed optimal activity at a pH of 7.5 and temperature of 40°C. The kinetic parameters Vmax and Km were 45.32 U ml-1 and 61.11 mM respectively.The honey extracts inhibited the activity of the crude urease in a concentration dependent manner. The Lineweaver-Burk plots indicated a non-competitive type of inhibition against H. pylori urease. The two honey extracts gave promising inhibitory activities against urease of H. pylori. Thus the results of this study delineates that inhibition of urease can ease development in therapeutic and preventative approaches based on the enzymatic activity of this Helicobacter protein.

abstract: Vitellogenin (Vg) is an ancient and highly conserved multifunctional protein. It is primarily known for its role in egg-yolk formation but also serves functions pertaining to immunity, longevity, nutrient storage, and oxidative stress relief. In the honey bee (Apis mellifera), Vg has evolved still further to include important social functions that are critical to the maintenance and proliferation of colonies. Here, Vg is used to synthesize royal jelly, a glandular secretion produced by a subset of the worker caste that is fed to the queen and young larvae and which is essential for caste development and social immunity. Moreover, Vg in the worker caste sets the pace of their behavioral development as they transition between different tasks throughout their life. In this dissertation, I make several new discoveries about Vg functionality. First, I uncover a colony-level immune pathway in bees that uses royal jelly as a vehicle to transfer pathogen fragments between nestmates. Second, I show that Vg is localized and expressed in the honey bee digestive tract and suggest possible immunological functions it may be performing there. Finally, I show that Vg enters to nucleus and binds to deoxyribonucleic acid (DNA), acting as a potential transcription factor to regulate expression of many genes pertaining to behavior, metabolism, and signal transduction pathways. These findings represent a significant advance in the understanding of Vg functionality and honey bee biology, and set the stage for many future avenues of research. / Dissertation/Thesis / Doctoral Dissertation Evolutionary Biology 2019

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy / In this dissertation the physical and chemical alterations induced by mastication and manipulation of wax by the worker bee in honeycomb construction, and the subsequent contribution afforded the structural integrity of the nest, are elucidated. In comb building, the freshly secreted wax scales are mandibulated together with a frothy salivary emulsion, and added piece-meal to form honeycomb. Textural modifications were revealed using X-ray crystallography. While virgin scale wax is highly structured, with the crystallites aligned approximately perpendicular to the planar surface, comb wax has a random crystallographic arrangement. This reflects a disruption of the crystallite structure following the mechanical insult of mastication. Chemical analyses included investigation of both lipid and proteinaceous elements. Lipid composition was evaluated by enzyme-catalyzed as well as thin-layer and gas-liquid chromatographic methods. The results indicate a reduction in scale diacylglycerols with a corresponding increase in comb saturated monoaeylglycerols. Such modifications are highly suggestive of lipase activity within the salivary addition. The proteins of comb and scale wax were analyzed electrophoretically, under reduced conditions. Each wax possesses unique polypeptide fractions, in addition to sharing common protein species, It is speculated that those in common represent integral proteins, such as transport molecules, while the disparities noted may be due to salivary enzymatic degradation, or even glycosylation. The effects of these textural and chemical alterations on the mechanical behaviour of the waxes was assessed. Tensile tests were performed on a variety of scale and comb wax preparations over the range of temperatures likely to impinge on the honeybee nest. These investigations reveal the specific structural contributions made by each of the physico-chemical alterations described. Further, they demonstrate that while scales are ideal moulding materials due to their high distensibility and low stiffness, the greater resistance to deformation and lower potential for extension makes comb wax a superior structural material. The mechanical advantage for including propolis and cocoon silk within the comb structure was also investigated. Tensile testing indicates that the resultant composite material is structurally superior, largely due to the presence of silk reinforcement. / Andrew Chakane 2018

<p>    </p> <p>Domestication is the process by which a previously wild population is managed by humans, thereby being subjected to a different set of selective pressures than experienced in its natural setting. Its opposite, feralization, is therefore when a domesticate escapes or is released from a captive setting, reasserting natural selective pressures. The genomics underpinning both domesti- cation and feralization have not been studied in insects; the Western honey bee (<em>Apis mellifera </em>L.) is a good model for this system, as honey bees exist in both a managed and feral state, and have extensive historic and genomic resources to document population changes. My goal in this thesis was to 1) improve upon our understanding of honey bee importation and genetics to the United States to support demographic assertions, and 2) to sequence managed and feral stocks of honey bees to identify the population structure and 3) genetic differences underpinning domestication. Ultimately, I reconstructed 400 years of honey bee importation and management history, creating the most comprehensive understanding to date of importation dates and locations, historical man- agement practices, and genetic bottlenecks. Additionally, I summarized thirty years of honey bee genome sequencing to provide a road map for future studies. Then, I conducted whole genome pooled sequencing on six managed and three feral stocks of honey bees from the United States. The mitochondrial and whole genome ancestry of feral colonies holds relics from their importation history, while managed colonies show evidence of more recent importation events. The managed stocks in my sample set have higher overall genetic diversity, but exhibit little differentiation, but feral stocks exhibit varying levels of differentiation, indicating different levels of ferality likely dictated by the level of reproductive isolation from managed colonies. </p>

Honey bees can form distinct spatiotemporal memories that allow them to return repeatedly to different food sources at different times of day. Although it is becoming increasingly clear that different behavioral states are associated with different profiles of brain gene expression, it is not known whether this relationship extends to states that are as dynamic and specific as those associated with foraging-related spatiotemporal memories. We tested this hypothesis by training different groups of foragers from the same colony to collect sucrose solution from one of two artificial feeders; each feeder was in a different location and had sucrose available at a different time, either in the morning or afternoon. Bees from both training groups were collected at both the morning and afternoon training times to result in one set of bees that was undergoing stereotypical food anticipatory behavior and another that was inactive for each time of day. Between the two groups with the different spatiotemporal memories, microarray analysis revealed that 1329 genes were differentially expressed in the brains of honey bees. Many of these genes also varied with time of day, time of training or state of food anticipation. Some of these genes are known to be involved in a variety of biological processes, including metabolism and behavior. These results indicate that distinct spatiotemporal foraging memories in honey bees are associated with distinct neurogenomic signatures, and the decomposition of these signatures into sets of genes that are also influenced by time or activity state hints at the modular composition of this complex neurogenomic phenotype.

In the field of insect circadian rhythms, the honey bee is best known for its foraging time-sense, or Zeitgedächtnis, which permits the forager bee to make precise associations between the presence of food and the time of day. A number of studies, now considered classics, established that bees could be trained to collect food at virtually any time of the circadian cycle and that this timekeeping ability was controlled by an endogenous circadian clock. Recently, behavioral rhythms in bees have been examined using a variety of approaches, in both laboratory and field studies. The following areas of new research are reviewed: (a) the ontogeny of behavioral rhythmicity in newly emerged worker bees; (b) the integration of behavioral rhythmicity with the colony's division of labor; (c) the evidence for social entrainment of behavioral rhythms and for a 'clock of the colony'; (d) the potential linkage between circadian rhythms of general locomotor activity and the foraging time-sense; (e) learning and entrainment hypotheses proposed to explain the mechanism underlying the time-sense; (f) the interplay between extinction and persistence of the time-memory as revealed from the differential behavior of individuals within the foraging group; and (g) comparisons of the Zeitgedächtnis with food-anticipatory rhythms in other animals.

Honey bees utilize their circadian rhythms to accurately predict the time of day. This ability allows foragers to remember the specific timing of food availability and its location for several days. Previous studies have provided strong evidence toward light/dark cycles being the primary Zeitgeber for honey bees. Work in our laboratory described large individual variation in the endogenous period length of honey bee foragers from the same colony and differences in the endogenous rhythms under different constant temperatures. In this study, we further this work by examining the temperature inside the honey bee colony. By placing temperature and light data loggers at different locations inside the colony we measured temperature at various locations within the colony. We observed significant oscillations of the temperature inside the hive, that show seasonal patterns. We then simulated the observed temperature oscillations in the laboratory and found that using the temperature cycle as a Zeitgeber, foragers present large individual differences in the phase of locomotor rhythms for temperature. Moreover, foragers successfully synchronize their locomotor rhythms to these simulated temperature cycles. Advancing the cycle by six hours, resulting in changes in the phase of activity in some foragers in the assay. The results are shown in this study highlight the importance of temperature as a potential Zeitgeber in the field. Future studies will examine the possible functional and evolutionary role of the observed phase differences of circadian rhythms.