Amphioxus Immunity

Tracing the Origins of Human Immunity

An-Long Xu

• Publisher: Academic Press
• Year: 2015
• Print ISBN: 9780128499030
• eBook ISBN: 9780128096475
• Topic: Medicine
• Subtopic: Immunology

Amphioxus Immunity: Tracing the Origin of Human Immunity covers a remarkable range of information about Amphioxus and its evolutionary context. This compilation of what is currently known about Amphioxus, with a sharp focus on its immune system, includes 13 topics, such as: - Amphioxus as a model for understanding the evolution of vertebrates- basic knowledge of immunology- immune organs and cells of amphioxus- a genomic and transcriptomic view of the Amphioxus immunity- pattern recognition system in Amphioxus- transcription factors in Amphioxus- the complement system of Amphioxus- the oxidative burst system in Amphioxus- immune effectors in Amphioxus- lipid signaling of immune response in Amphioxus- apoptosis in amphioxus; primitive adaptive immune system of Amphioxus- and future research directions This valuable reference book is loaded with information that will be useful for anyone who wishes to learn more about the origin of vertebrates and adaptive immunity.- Provides new evidence on the origin of the adaptive immune system, the evolution of innate immunity, and evolution-stage specific immune defense mechanisms- Not only presents the cells and molecules involved in the adaptive immune response in Amphioxus, but also characterizes the origination and evolution of the gene families and pathways involved in innate immunity- Includes much pioneering work, from the molecular, genomic, and cellular to the individual level

Chapter 1

Amphioxus as a Model for Understanding the Evolution of Vertebrates

Yuchao Feng^*

Jun Li^**

Anlong Xu^†
* Guangdong Provincial Hospital of Traditional Chinese Medicine, South China Sea Institute of Oceanology, Chinese Academy of Sciences
^** Liaocheng University
^† Sun Yat-sen University, Guangzhou, China

Abstract

This chapter introduces the biology of amphioxus and discusses the research history of this living fossil. Amphioxus was first discovered in Europe as a lancelet. Taxonomically, it belongs to the subphylum Cephalochordata, which means “chordate in the head.” The fossil evidence, as well as the modern molecular phylogenetic tree, suggests amphioxus as the most basal chordate. The body plan and embryonic development of amphioxus are close to its vertebrate ancestors. It was used as a model animal for developmental studies since the nineteenth century. The famous Chinese zoologist Tung Tichou made many contributions to the developmental research of amphioxus. Amphioxus can now be used as a model for the study of the origin of vertebrate immunity.

Keywords

protochordate

lancelet

Wenchang fish

living fossil

Tung Tichou

Contents

1.1 Brief introduction of amphioxus 1

1.2 Biology of amphioxus 3

1.2.1 Reproduction and embryogenesis of amphioxus 4

1.2.2 Anatomy of amphioxus 6

1.3 The story of amphioxus and early research studies in China 10

References 12

1.1. Brief introduction of amphioxus

The amphioxus was first described by Peter Simon Pallas (1774). Also, the Russian zoologist Alexander Kowalevsky (1867) did extensive pioneering work on amphioxus embryology. He noted that the late embryonic development of amphioxus has many features of vertebrates, such as notochords. This discovery supported the concept that protochordates were the closest living relatives of vertebrates.

The fossils of invertebrate chordates give additional support of amphioxus as the model for ancestral vertebrates (Holland et al., 2004). Haikouella, a 530-million-year-old fossil found in Haikou, Yunnan province, China (Mallatt and Chen, 2003), is known for the anatomy of protochordate and vertebrate features. It possesses the typical features of protochordate amphioxus, such as a notochord, pharynx, and dorsal nerve cord (Figure 1.1). But, more importantly, Haikouella seems to have a dorsal ventral aorta, heart, and neural crest (Chen, 2008). This indicates that amphioxus has the primitive body plan of ancestral vertebrates and is a living fossil close to the origin of vertebrates.

Figure 1.1 Comparison of Reconstructed Haikouella and Amphioxus.
(A) Showing the feature of Haikouella, which possesses similar structure such as dorsal nerve cord, notochord, postanal tail, which is also in (B) amphioxus. This indicates that the amphioxus is the most primitive chordates and has the features of common vertebrates ancestors. Adapted from Holland et al. (2004).

Amphioxus has long been regarded a key phylogenetic model animal in the research on the origin of vertebrates. Molecular phylogenetic analyses (Figure 1.2) have placed cephalochordates as the most basal chordate group (Blair and Hedges, 2005; Delsuc et al., 2006; Vienne and Pontarotti, 2006; Putnam et al., 2008). Unlike the much-reduced metamorphosis of the tunicates, cephalochordates have maintained...

Table of contents

• Cover
• Title page
• Table of Contents
• Copyright
• Dedication
• List of Contributors
• About the Author
• Foreword
• Preface
• Chapter 1: Amphioxus as a Model for Understanding the Evolution of Vertebrates
• Chapter 2: Basic Knowledge of Immunology
• Chapter 3: Immune Organs and Cells of Amphioxus
• Chapter 4: Genomic and Transcriptomic View of Amphioxus Immunity
• Chapter 5: Pattern Recognition System in Amphioxus
• Chapter 6: Transcription Factors in Amphioxus
• Chapter 7: The Complement System of Amphioxus
• Chapter 8: The Oxidative Burst System in Amphioxus
• Chapter 9: Immune Effectors in Amphioxus
• Chapter 10: Evolution of Inflammation-Related Lipid Metabolism Pathway and Inflammatory Lipid Signaling in Amphioxus
• Chapter 11: Apoptosis in Amphioxus
• Chapter 12: Primitive Adaptive Immune System of Amphioxus
• Chapter 13: Future Research Directions
• Abbreviation Index
• Subject Index