Amino acid content in the anterior and posterior tissues of earthworms determined by acid hydrolysis

Although earthworms (Eisenia fetida) are widely used in ecological toxicology research, existing work mostly focuses on the overall level and ignores the metabolic heterogeneity brought about by their significant physiological functional zoning - the anterior segment tissue serves as a neural regulatory center, while the posterior segment tissue undertakes motor, energy metabolism, and exogenous detoxification functions.

Amino acids, as key metabolites connecting neural transmission, redox balance, and heavy metal chelation, are an ideal entry point for revealing tissue-specific responses. However, current research on the amino acid metabolism of earthworms under Cd stress still lacks systematic integration of tissue resolution, temporal dynamics, and concentration gradients, which limits a deeper understanding of the metabolic network regulation mechanisms under long-term toxicity effects and makes it difficult to provide sufficient molecular evidence for accurate risk assessment of soil heavy metal pollution.