Investigating the Immune System and Colonialism in Sea Urchins

Abstract

Sea urchins are relegated as background or non-playable characters in Western Science and Western culture on a daily basis. This dissertation shines a spotlight on my non-human relatives and gives readers a chance to learn about the sciences and cultures that sea urchin species play a role in. Along with offering research within the realms of development biology and immunology, there are pieces relevant to Science & Society and general audience blended throughout the chapters. I address two major problems in this work. The first problem is determining how the complex immune system of the Lytechinus variegatus larva develops and reacts to injury. The second, is uncovering what colonial practices have led to the sea urchin research climate today.The first chapter of this dissertation offers a broad Introduction to sea urchins. Moving away from a “cold” or impersonal description, you’ll learn about the diversity of sea urchins that move about the world’s oceans every day. Topics include what urchin’s eat, their etymological origin, their influence on historical and contemporary cultures, what some taste like, and other ranging topics. Parallel to these topics, this chapter contains basic biology on the adult and larval sea urchin, and the development of the embryo’s mesenchyme cell populations, which will be the foci of multiple chapters. Moving into wet lab research, chapter 2 provides the methods used in molecular, cellular, and embryological experiments. The major novel research method is an injury assay where we are able crush or “squish” L. variegatus larvae, causing a reproducible and quick immune cell response. Chapter 3 involves a review and recommendations on how Western Science developmental biology researchers think about and approach studying the larva’s mesenchyme. Using these new practices, we were able to uncover tissue specific candidate markers in silico, by cloning, and through expression data. Chapter 4 is the characterization of the immune-related cytokine family, the macrophage migration inhibitory factors (MIFs) in sea urchins. Utilizing newly published genomes, we were able to provide a fuller description of MIF gene duplications, and confidently clone select MIFs and perturb candidate regulators. The following chapter addresses the conundrum of wound healing and the immune system’s role in the process. By crushing L. variegatus larvae, we have been able to describe and characterize roles of pigment and blastocoelar cells in epithelial and skeletal wound repair. Our conclusions for the respective chapters are, the MIF family has gone through a major gene duplication, and are now able to perform tissue specific and potentially redundant roles in immune cell function; and pigment cells and blastocoelar cell networks are activated quickly in injuries and can remodel tissues in the larvae. The Science & Society, and penultimate chapter of this dissertation takes a deeper look into why Western Scientists study sea urchin, doing so through the lens of colonialism. In outlining personal kinship, obligations, and an interdisciplinary lens, I am able to name the colonial intentions of marine stations and their use of invertebrate species as research materials. For a contemporary example, I name general instances of colonial research methods and propose select ways to promote anti- and decolonial practices in sea urchin science that move beyond metaphors. This project, and the questions it answers and generates moves away from myths of Western Science such as neutrality, and away from a spiritless resource for academic consumption. Along with learning about the immune system, cytokines, and injury response from my non-human, sea urchin relatives, we can also begin to address broad and systemic problems that are faced in sea urchin science and culture. My goal, and what should be thought about early in reading this work, is to learn from, appreciate, reciprocate, respect, and co-create knowledge with sea urchins in a way that doesn’t harm the Land.