Invertebrate faunal species have served as “model systems” for clinical research work and academic teaching since the late 1800s. Due to their low cost, easy handling and manipulation, genetic amenability, time effectiveness, compatibility of their culture conditions with large-scale screens and most importantly the simplicity of their biology that enables us to perform experiments and identify key modulators of conserved biological processes before their discovery and assessment in more complex vertebrate models, invertebrate models have been highly acclaimed.
One of the most reliable and efficient invertebrate models in Caenorhabditis elegans. Utilization of C. elegans has helped in bridging the gap between “traditional in vitro evaluations” and “preclinical animal assays”. As the general masses have invoked their concerns about the use of vertebrates in research work, invertebrate models have further gained more momentum in the past several decades.
Their use in drug discovery, transgenic biology, developmental genetics, studies about neurodegenerative diseases, chemical genetics, embryology and aging processes studies has been monumental and worth mentioning.
The topic, as complex as it may sound, can never be overhyped. Their use in research has helped immensely across different domains of science. Despite being a fascinating topic for discussion and learning, students in schools and colleges find this subject to be hard. With a lot of facts and information at hand in the age of Google, students often lose track of how and what to learn about invertebrate model systems. Since this topic requires one to ruminate and find the logic behind facts, teachers often find it challenging to plan and deliver insightful lectures.
We, at Labster, understand the complexities of this subject. This article can provide some help as it attempts to identify the major obstacles encountered by students whilst studying this topic. It also lists practical solutions that teachers and educators can incorporate in their next class. By the end, we’ll convince you why a virtual lab simulation will be helpful not only for your students but also for you as an educator to deliver concepts more efficiently.
There are 3 reasons why students dread and get confused about the topic of the Invertebrate Model System. Acknowledging these blocks is the first step toward making the topic more approachable.
This is the foremost reason that students often feel challenged when dealing with these model systems in their practical classes. Lack of knowledge about the “basic biology of invertebrates'' and not knowing how they are different from vertebrates in different aspects lands many students in a challenging situation. In particular, when dealing with C. elegans, students fail to identify the pros and cons of using this model system. Not knowing that “a significant protein divergence exists between invertebrates and humans (vertebrates)”, students falsely report some data and make inaccurate conclusions about vertebrates. If they don’t take into account this discrepancy, this can potentially lead to a high rate of false negatives. One is required to critically assess the results and look out for meaningful findings when using such invertebrate model systems for vertebrate studies.
This is another troubling issue with many students as theory is very different from practical handling. Invertebrate model systems are biological entities and like any other organism, they can sometimes be unpredictable. Good lab practices are often missed out and students are taught steps and numbers in most labs across the world. Due attention is seldom paid to this issue. This reflects when students aren’t able to properly care for their model systems. While handling C. elegans, a lack of knowledge about their bacterial food source, growth conditions, Nematode Growth Medium (NGM), stock maintenance, etc can further aggravate the situation for students.
Teaching students about the utilization of these invertebrate model systems can be hampered due to the unavailability of required apparatus, equipment and instruments in many labs. Further, strains of C. elegans need to be sourced before one plans to begin an experiment. Their growth, maintenance and long-term storage further require specific conditions, thereby making the availability of incubators, autoclaves, centrifuges, shakers, pipettes, vortex, -80 degree cold storage systems, etc indispensable. In absence of these facilities, teaching them about their importance becomes impossible for educators. Further, the lack of videos and animated alternatives leaves no chance for educators to even demonstrate the essential lab handling practices.
To address the issues encountered while teaching about Invertebrate Model System, educators can engage the under-listed solutions in their classes. Not only can they make teaching easier for educators like you, but they will also make lessons clearer and easier to assimilate for your students.
We recommend educators pay due attention to the core concepts related to this topic. The art of objective analysis and strong basic science concepts are underrated when pursuing a research career. Educators should highlight the vitality of this combination as the techniques keep advancing while the analysis skills depend on one’s objectivity and conversance with core fundamental ideas. We list a few topics that you can work on while teaching about invertebrate model systems to students in your next class.
Difference between vertebrates and invertebrates
The idea of model systems and different types (Escherichia coli, Caenorhabditis elegans, Drosophila melanogaster, Arabidopsis thaliana, yeast, mouse, chicken)
Ethical issues when working with model systems
Commonly used model systems for biomedical studies
Pros and cons of using Caenorhabditis elegans as a model system
Methods to differentiate between male and hermaphrodite C. elegans
Educate your students about the biology of C. elegans. When students are well-versed in the intricacies of a biological system, working with it in the lab becomes quite easier. We list some of the tips and tricks to educate your students about C. elegans.
Sexes in C. elegans: The sexes in C. elegans are defined by the number of sex chromosomes. A male worm has only 1 X chromosomes (genotype: XO) while a hermaphrodite has 2 X chromosomes (genotype: XX). Educate your students on how they can differentiate between the two sexes; males have a spade-shaped tail, while hermaphrodites don’t.
Population representation in C. elegans: Under normal conditions, male C. elegans (XO) account for only 0.1% of the population. (Reason: Due to nondisjunction of X chromosomes)While under some stressful conditions like food scarcity/heat, this rate is higher.
Reproductionin C. elegans: C. elegans display both self-fertilization and sexual reproduction. During sexual reproduction, the number of males is much higher (50%) because male sperm outcompetes the sperm from hermaphrodites. Furthermore, a hermaphrodite inseminated by a male can lay up to 1000 eggs as opposed to 300 during self-fertilization.
Figure: A schematic representation of the life cycle of C. elegans. Image Source
Since the model system is a biological organism, we should teach our students how to grow, maintain, care and store the organism for our lab studies. The biological life in our hands is quite fragile, so one should be proficient in handling it. We provide a list of handling tips for C. elegans.
Concept of starvation at the permissive temperature
Formation of heat-resistant dauer larvae
Preparation of growth media for C. elegans
Preparation of bacterial food source
Preparation of fresh Nematode Growth Medium (NGM) plates
Handling micropipettes, centrifuge, vortex, shakers, and incubators in labs (You can use the Pipetting: Selecting and Using Micropipettes simulation and Pipetting: Master the technique simulation from Labster)
Different methods for transferring C. elegans from one Petri plate to another (chunking, using sterilized filter paper, using a worm picker)
Another important thing that educators can incorporate in their teaching sessions is to enlighten their students about the different techniques used for C. elegans analysis. We list some of them for you.
Genetic screens: Genetic screens are used to select certain phenotypic characters over others. These phenotypes are usually a manifestation of a specific gene in a mutagenized population. Selection of these phenotypes can help in identifying the biological pathway that’s getting altered.
Types of genetic screens: Educate them about the two types of screens; forward and reverse genetic screens. While in a forward screen, we identify the genes based on a known phenotypic character; on the other hand in a reverse screen the phenotypic character is analyzed based on a known gene or set of genes.
Concept of GFP and fluorescence microscopy: You can use the Fluorescence Microscopy simulation from Labster.
Figure: GFP structure. Image Source
Since the topic of invertebrate model systems is a complex subject to teach with only textual tools, we recommend educators use videos and simulations to make the topic interesting for their students.
Since the strains of model systems like C. elegans need to be sourced before planning experiments, and occasions of not having the same can leave students with no option to get their hands dirty in the labs. To overcome the lack of practical lab handling experience, we have brought the Invertebrate Model System simulation. As they delve deeper into the process of finding the mutated protein, they can learn how to handle the organism, its life cycle and how one is supposed to run different screening experiments.
With virtual laboratory simulations from Labster, teachers can make more insightful points as students are rendered with better visual options where they can follow the different concepts in a free-flowing manner. Our simulation, with its unique gamification elements, will save the day for you. By using this way of active and immersive teaching, our virtual learning platform takes an advent in the field of Science to make the upcoming scientists thorough with the “basics of their respective subjects”.
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