Purpose

Earthworm mucus is a ubiquitous source of C and N for soil biochemical processes and likely fuels direct interactions with other soil organisms; however, its chemical composition is little known and was the research question addressed by this research. A method was developed for the collection of sufficient amounts of cutaneous mucus from highly isotopically labelled earthworms with the objective to analyse mucus chemically by state-of-the-art nuclear magnetic resonance (NMR) techniques.

Materials and methods

A clean sand method was developed to collect cutaneous mucus from highly ¹³C, ¹⁵N-labelled endogeic earthworms (Allolobophora chlorotica). Mucus was analysed by 1D and 2D NMR.

Results and discussion

NMR spectra showed a complex mixture dominated by carbohydrates with a high aliphatic/lipid content and relatively few resonances for protein/peptide material. A very large contribution from acetate was detected, likely in the form of acetylated carbohydrates.

Conclusions

The ample presence of acetate is noteworthy because acetate is an important component in soil carbon cycling and methanogenic pathways. Earthworm mucus may be involved in novel direct biochemical interactions with soil (and possibly also sediment) microorganisms and plant roots that have not been recognised before.

中文翻译：

---

皮肤earth粘液中存在大量乙酸盐的证据

目的

mu粘液是土壤生化过程中普遍存在的碳和氮源，可能促进与其他土壤生物的直接相互作用。然而，其化学成分鲜为人知，是本研究解决的研究问题。开发了一种从高度同位素标记的earth中收集足量皮肤粘液的方法，目的是通过最新的核磁共振（NMR）技术进行化学分析。

材料和方法

开发了一种干净的砂方法，以从高度¹³ C，¹⁵ N标记的内生earth（Allolobophora chlorotica）收集皮肤粘液。通过1D和2D NMR分析粘液。

结果和讨论

NMR谱显示复杂的混合物以碳水化合物为主，脂肪族/脂类含量高，蛋白质/肽类物质的共振相对较少。检测到乙酸盐的贡献很大，很可能是乙酰化碳水化合物的形式。

结论

乙酸盐的充足存在是值得注意的，因为乙酸盐是土壤碳循环和产甲烷途径中的重要成分。mu的粘液可能参与了与土壤（可能还有沉积物）的微生物和植物根系的新的直接生化相互作用，而以前从未认识到。