奥地利维也纳大学Wagner, Michael团队报道了完全氨氧化剂在胍上的生长。相关研究成果于2024年8月14日发表在国际知名学术期刊《自然》。

胍是一种化学稳定的氮化合物，可在人体尿液中排出，广泛用于塑料制造、阻燃剂和推进剂成分，在生物化学中是众所周知的蛋白质变性剂。胍在自然界中广泛存在，被几种微生物用作氮源，但在胍作为唯一底物上生长的微生物尚未被鉴定出来。

该文中，研究表明，完全氨氧化剂氨氧化剂(comammox)硝基螺旋菌(Nitrospira inopinata)和大多数其他comammox微生物可以在胍上生长，胍是唯一的能量、还原剂和氮源。蛋白质组学、酶动力学和N.inopinata胍酶同源物的晶体结构表明，它是一种真正的胍酶。

用含comammox的农业土壤和污水处理厂微生物群进行的孵化实验表明，胍是环境中硝化作用的底物。胍作为comammox生长底物的鉴定，显示了这些全球重要硝化细菌的一个意想不到的生态位，并为它们的分离提供了机会。

附：英文原文

Title: Growth of complete ammonia oxidizers on guanidine

Author: Palatinszky, Marton, Herbold, Craig W., Sedlacek, Christopher J., Phringer, Dominic, Kitzinger, Katharina, Giguere, Andrew T., Wasmund, Kenneth, Nielsen, Per H., Dueholm, Morten K. D., Jehmlich, Nico, Gruseck, Richard, Legin, Anton, Kostan, Julius, Krasnici, Nesrete, Schreiner, Claudia, Palmetzhofer, Johanna, Hofmann, Thilo, Zumstein, Michael, Djinovi-Carugo, Kristina, Daims, Holger, Wagner, Michael

Issue&Volume: 2024-08-14

Abstract: Guanidine is a chemically stable nitrogen compound that is excreted in human urine and is widely used in manufacturing of plastics, as a flame retardant and as a component of propellants, and is well known as a protein denaturant in biochemistry1,2,3. Guanidine occurs widely in nature and is used by several microorganisms as a nitrogen source, but microorganisms growing on guanidine as the only substrate have not yet been identified. Here we show that the complete ammonia oxidizer (comammox) Nitrospira inopinata and probably most other comammox microorganisms can grow on guanidine as the sole source of energy, reductant and nitrogen. Proteomics, enzyme kinetics and the crystal structure of a N. inopinata guanidinase homologue demonstrated that it is a bona fide guanidinase. Incubation experiments with comammox-containing agricultural soil and wastewater treatment plant microbiomes suggested that guanidine serves as substrate for nitrification in the environment. The identification of guanidine as a growth substrate for comammox shows an unexpected niche of these globally important nitrifiers and offers opportunities for their isolation.

DOI: 10.1038/s41586-024-07832-z

Source: https://www.nature.com/articles/s41586-024-07832-z