Matching Items (8)

128820-Thumbnail Image.png

Morphometric Identification of Queens, Workers and Intermediates in In Vitro Reared Honey Bees (Apis mellifera)

Description

In vitro rearing is an important and useful tool for honey bee (Apis mellifera L.) studies. However, it often results in intercastes between queens and workers, which are normally are

In vitro rearing is an important and useful tool for honey bee (Apis mellifera L.) studies. However, it often results in intercastes between queens and workers, which are normally are not seen in hive-reared bees, except when larvae older than three days are grafted for queen rearing. Morphological classification (queen versus worker or intercastes) of bees produced by this method can be subjective and generally depends on size differences. Here, we propose an alternative method for caste classification of female honey bees reared in vitro, based on weight at emergence, ovariole number, spermatheca size and size and shape, and features of the head, mandible and basitarsus. Morphological measurements were made with both traditional morphometric and geometric morphometrics techniques. The classifications were performed by principal component analysis, using naturally developed queens and workers as controls. First, the analysis included all the characters. Subsequently, a new analysis was made without the information about ovariole number and spermatheca size. Geometric morphometrics was less dependent on ovariole number and spermatheca information for caste and intercaste identification. This is useful, since acquiring information concerning these reproductive structures requires time-consuming dissection and they are not accessible when abdomens have been removed for molecular assays or in dried specimens. Additionally, geometric morphometrics divided intercastes into more discrete phenotype subsets. We conclude that morphometric geometrics are superior to traditional morphometrics techniques for identification and classification of honey bee castes and intermediates.

Contributors

Agent

Created

Date Created
  • 2015-04-20

128043-Thumbnail Image.png

Gustatory Perception and Fat Body Energy Metabolism Are Jointly Affected by Vitellogenin and Juvenile Hormone in Honey Bees

Description

Honey bees (Apis mellifera) provide a system for studying social and food-related behavior. A caste of workers performs age-related tasks: young bees (nurses) usually feed the brood and other adult

Honey bees (Apis mellifera) provide a system for studying social and food-related behavior. A caste of workers performs age-related tasks: young bees (nurses) usually feed the brood and other adult bees inside the nest, while older bees (foragers) forage outside for pollen, a protein/lipid source, or nectar, a carbohydrate source. The workers' transition from nursing to foraging and their foraging preferences correlate with differences in gustatory perception, metabolic gene expression, and endocrine physiology including the endocrine factors vitellogenin (Vg) and juvenile hormone (JH). However, the understanding of connections among social behavior, energy metabolism, and endocrine factors is incomplete. We used RNA interference (RNAi) to perturb the gene network of Vg and JH to learn more about these connections through effects on gustation, gene transcripts, and physiology. The RNAi perturbation was achieved by single and double knockdown of the genes ultraspiracle (usp) and vg, which encode a putative JH receptor and Vg, respectively. The double knockdown enhanced gustatory perception and elevated hemolymph glucose, trehalose, and JH. We also observed transcriptional responses in insulin like peptide 1 (ilp1), the adipokinetic hormone receptor (AKHR), and cGMP-dependent protein kinase (PKG, or “foraging gene” Amfor). Our study demonstrates that the Vg–JH regulatory module controls changes in carbohydrate metabolism, but not lipid metabolism, when worker bees shift from nursing to foraging. The module is also placed upstream of ilp1, AKHR, and PKG for the first time. As insulin, adipokinetic hormone (AKH), and PKG pathways influence metabolism and gustation in many animals, we propose that honey bees have conserved pathways in carbohydrate metabolism and conserved connections between energy metabolism and gustatory perception. Thus, perhaps the bee can make general contributions to the understanding of food-related behavior and metabolic disorders.

Contributors

Agent

Created

Date Created
  • 2012-06-28

135152-Thumbnail Image.png

Testing the Limits of Ethical Issues within the Field of Genetic Counseling

Description

Genetic counseling is a medical field that was established in the 1970s, but whose demand is now growing exponentially due to modern genetic technology. We now have the ability to

Genetic counseling is a medical field that was established in the 1970s, but whose demand is now growing exponentially due to modern genetic technology. We now have the ability to look into the human genetic code, detect the genotype of individuals, and use this knowledge to our benefit. However, Genetic testing results in a need for new ethical boundaries to be drawn. The idea of the "best possible conditions" of conceiving a child and whether this child has a right to not know are the two major ethical issues that will be focused on in order to analyze the ethical boundary that needs to be drawn for genetic counseling. In order to analyze these ethical issues, a focus group of Arizona State University students was organized. After producing results for the focus group, there are no true conclusions that can be drawn that applied to all of society. The focus group sample size was too small to produce a broad range of results and the participants were all Arizona State University Undergraduate students. However, it did become apparent that knowledge on these ethical issues is crucial in order to ensure they do not hinder the field of genetic counseling. It is predicted that in order to have the best outcome for the field of genetic counseling, genetic counselors themselves need to draw the ethical boundaries for the issues studied.

Contributors

Agent

Created

Date Created
  • 2016-05

135022-Thumbnail Image.png

The Role of the Biogenic Amine Tyramine in Latent Inhibition Learning in the Honey Bee, Apis mellifera

Description

Animals must learn to ignore stimuli that are irrelevant to survival, a process referred to as latent inhibition. The Amtyr1 gene has been shown through quantitative trait loci mapping to

Animals must learn to ignore stimuli that are irrelevant to survival, a process referred to as latent inhibition. The Amtyr1 gene has been shown through quantitative trait loci mapping to be linked to strong latent inhibition in honey bees. Here we implicate this G-protein coupled receptor for the biogenic amine tyramine as an important factor underlying this form of learning in honey bees. We show that dsRNA targeted to disrupt the tyramine receptors, specifically affects latent inhibition but not excitatory associative conditioning. Our results therefore identify a distinct reinforcement pathway for latent inhibition in insects.

Contributors

Agent

Created

Date Created
  • 2016-12

134156-Thumbnail Image.png

Vitellogenin Expression and Deformed Wing Virus Replication in Apis mellifera

Description

Vitellogenin (vg) is a precursor protein of egg yolk in honeybees, but it is also known to have immunological functions. The purpose of this experiment was to determine the effect

Vitellogenin (vg) is a precursor protein of egg yolk in honeybees, but it is also known to have immunological functions. The purpose of this experiment was to determine the effect of vg on the viral load of deformed wing virus (DWV) in worker honey bees (Apis mellifera). I hypothesized that a reduction in vg expression would lead to an increase in the viral load. I collected 180 worker bees and split them into four groups: half the bees were subjected to a vg gene knockdown by injections of double stranded vg RNA, and the rest were injected with green fluorescent protein (gfp) double stranded RNA. Half of each group was thereafter injected with DWV, and half given a sham injection. The rate of mortality in all four groups was higher than expected, leaving only 17 bees total. I dissected these bees' fat bodies and extracted their RNA to test for vg and DWV. PCR results showed that, out of the small group of remaining bees, the levels of vg were not statistically different. Furthermore, both groups of virus-injected bees showed similar viral loads. Because of the high mortality rate bees and the lack of differing levels of vg transcript between experimental and control groups, I could not draw conclusions from these results. The high mortality could be caused by several factors: temperature-induced stress, repeated stress from the two injections, and stress from viral infection. In addition, it is possible that the vg dsRNA batch I used was faulty. This thesis exemplifies that information cannot safely be extracted when loss of sampling units result in a small datasets that do not represent the original sampling population.

Contributors

Agent

Created

Date Created
  • 2017-12

134942-Thumbnail Image.png

Ecdysone Effect on Hypopharyngeal Glands and Ovarioles in Adult Worker Bees (Apis mellifera)

Description

Division of labor is a hallmark for social insects and is closely related to honey bee morphology and physiology. Vitellogenin (Vg), a precursor protein in insect egg yolk, has several

Division of labor is a hallmark for social insects and is closely related to honey bee morphology and physiology. Vitellogenin (Vg), a precursor protein in insect egg yolk, has several known functions apart from serving as a nutrient source for developing eggs. Vg is a component in the royal jelly produced in the hypopharyngeal glands (HPG) of worker bees which is used to feed both the developing brood and the queen. The HPG is closely associated with divisions of labor as the peak in its development corresponds with the nursing behavior. Independent of the connection between Vg and the HPG, Vg has been seen to play a fundamental role in divisions of labor by affecting worker gustatory responses, age of onset of foraging, and foraging preferences. Similar to Vg, the number of ovarioles in worker ovaries is also associated with division of labor as bees with more ovarioles tend to finish tasks in the hive and become foragers faster. This experiment aims to connect HPGs, ovaries, and Vg by proposing a link between them in the form of ecdysone (20E). 20E is a hormone produced by the ovaries and is linked to ovary development and Vg by tyramine titers. By treating young emerged bees with ecdysone and measuring HPG and ovary development over a trial period, this experiment seeks to determine whether 20E affects division of labor through Vg. We found that though the stress of injection caused a significant decrease in development of both the ovaries and HPG, there was no discernable effect of 20E on either of these organs.

Contributors

Agent

Created

Date Created
  • 2016-12

128856-Thumbnail Image.png

Honey Bee PTEN – Description, Developmental Knockdown, and Tissue-Specific Expression of Splice-Variants Correlated with Alternative Social Phenotypes

Description

Background
Phosphatase and TENsin (PTEN) homolog is a negative regulator that takes part in IIS (insulin/insulin-like signaling) and Egfr (epidermal growth factor receptor) activation in Drosophila melanogaster. IIS and Egfr

Background
Phosphatase and TENsin (PTEN) homolog is a negative regulator that takes part in IIS (insulin/insulin-like signaling) and Egfr (epidermal growth factor receptor) activation in Drosophila melanogaster. IIS and Egfr signaling events are also involved in the developmental process of queen and worker differentiation in honey bees (Apis mellifera). Here, we characterized the bee PTEN gene homologue for the first time and begin to explore its potential function during bee development and adult life.
Results
Honey bee PTEN is alternatively spliced, resulting in three splice variants. Next, we show that the expression of PTEN can be down-regulated by RNA interference (RNAi) in the larval stage, when female caste fate is determined. Relative to controls, we observed that RNAi efficacy is dependent on the amount of PTEN dsRNA that is delivered to larvae. For larvae fed queen or worker diets containing a high amount of PTEN dsRNA, PTEN knockdown was significant at a whole-body level but lethal. A lower dosage did not result in a significant gene down-regulation. Finally, we compared same-aged adult workers with different behavior: nursing vs. foraging. We show that between nurses and foragers, PTEN isoforms were differentially expressed within brain, ovary and fat body tissues. All isoforms were expressed at higher levels in the brain and ovaries of the foragers. In fat body, isoform B was expressed at higher level in the nurse bees.
Conclusion
Our results suggest that PTEN plays a central role during growth and development in queen- and worker-destined honey bees. In adult workers, moreover, tissue-specific patterns of PTEN isoform expression are correlated with differences in complex division of labor between same-aged individuals. Therefore, we propose that knowledge on the roles of IIS and Egfr activity in developmental and behavioral control may increase through studies of how PTEN functions can impact bee social phenotypes.

Contributors

Agent

Created

Date Created
  • 2011-07-14

155638-Thumbnail Image.png

The role of the biogenic amine tyramine in latent inhibition learning in the honey bee, Apis mellifera

Description

Animals must learn to ignore stimuli that are irrelevant to survival, which is a process referred to as ‘latent inhibition’. This process has been shown to be genetically heritable (Latshaw

Animals must learn to ignore stimuli that are irrelevant to survival, which is a process referred to as ‘latent inhibition’. This process has been shown to be genetically heritable (Latshaw JS, Mazade R, Sinakevitch I, Mustard JA, Gadau J, Smith BH (submitted)). The locus containing the AmTYR1 gene has been shown through quantitative trait loci mapping to be linked to strong latent inhibition in honey bees. The Smith lab has been able to show a correlation between learning and the AmTYR1 receptor gene through pharmacological inhibition of the receptor. In order to further confirm this finding, experiments were designed to test how honey bees learn with this receptor knocked out. Here this G-protein coupled receptor for the biogenic amine tyramine is implemented as an important factor underlying latent inhibition in honey bees. It is shown that double-stranded RNA (dsRNA) and Dicer-substrate small interfering RNA (dsiRNA) that are targeted to disrupt the tyramine receptors specifically affects latent inhibition but not excitatory associative conditioning. The results therefore identify a distinct reinforcement pathway for latent inhibition in insects.

Contributors

Agent

Created

Date Created
  • 2017