The Impact of Increasing Concentrations of Ragweed Pollen on the Innate Immune System and Allergic Response of Drosophila Melanogaster

 

Introduction

Background Information & Relevance

Climate change is a prevalent issue nowadays, and it not only causes environmental distress but also goes to the extent where it impacts human health. Because carbon dioxide is essential for plant survival, many plants can grow faster and larger as carbon dioxide increases. Longer growing seasons and increased temperature has made the ragweed pollen thrive and release more pollen into the atmosphere (2). An airborne allergen, like pollen, can penetrate airways and exacerbate asthma (11). This influx of pollen in the atmosphere has led to the development of numerous asthmatic and allergic cases, in fact there are about 50 million Americans that have asthma in the United States alone (1). Increased and repetitive exposure to these substances can lead to the development of an allergic disorder, most commonly: asthma (3). Asthma is a chronic inflammatory disease and is complex to understand the development of this disease among individuals. 


Drosophila melanogaster are useful, invertebrate asthma models because of their simple physiologically structure that can be easily genetically manipulated because they possess the major organs relevant to asthma (7). The airway of  Drosophila melanogaster or the tracheae has a relatively simple architecture consisting of the whole organ being made of epithelial cells, which shares numerous physiological similarities with the human lung. Fruit flies are typically not used as an asthma-model system because they lack IgE, mast cells and immunoglobulins- key antibodies that are used in immune-atopic responses in humans (4). Nevertheless, although fruit flies do not possess these antibodies, their innate immune system is relatively simple because unlike humans they lack an adaptive immune system and only obtain an inmate immune system to fight back foreign toxins (5). The fruit fly’s simple immune system permits an unveiled view of the epithelial biology and innate immunity (5,6). As well, it has been believed that drosophila larvae can express an allergic response by rising to the surface of the food media when exposed to a reactive oxygen species (ROS) during their third instar larvae stage (7). Larvae dig into their food media to access fresh and more nutrient levels of food media, and can still manage to breathe underneath the substrate (10). This study will therefore test this theory by utilizing ragweed pollen, as the reactive oxygen species in the food media. 


This study is unique in analyzing how different proliferative allergens affected by climate change can provoke potential asthma reactions by utilizing fruit flies as a model based system that could add to the medical field in immunology. This experiment can also raise awareness of this onset trend of allergies that are increasing in relation to the changing climate and is fundamental to understand ragweed pollen’s ability to inflict an allergic reaction in a biological species. 

Hypothesis

If drosophila melanogaster are exposed to ragweed pollen, then they should exhibit oxygen deprivation by remaining at the surface of the food media because ragweed pollen is a reactive oxygen species and presents major mediators of inflammatory responses in the airway epithelium (2,5). 

 

Graphical Abstract

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Methodology

  1. Larvae Collection Method 

    1. Ensures that all  larvae are in third instar stage for experimentation 

    2. Adult flies lay eggs in unaffected culture vial, eggs grow into third instar after 3-4 days 

    3. Use sucrose solution to bring larvae to the surface for retrieval 

  2. Preparing Culture Vials 

    1. Prepare experimental vials 10 minutes prior to transferring larvae and beginning experimentation 

      1. Control Vial: Regular food media with no proliferative allergen (ragweed) 

      2. Experimental 1: 0.05µg of ragweed pollen  

      3. Experimental 2: 0.1 µg of ragweed pollen

      4. Experimental 3: 0.2 µg of ragweed pollen 

  3. Gathering Data 

    1. Count number of larvae at the surface until a depth of 1 millimeter into the food media- larvae are experiencing oxygen deprivation

  4. Statistical analysis

    1. Conduct an ANOVA test analyzing results 

    2. Create a written report of results

 
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Project Timeline

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