Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands.
Microbiology of Interfaces, Department of River Ecology, Helmholtz Centre of Environmental Research-UFZ, Brueckstrasse 3A, 39114 Magdeburg, Germany.
FEMS Microbiol Ecol. 2022 May 9;98(5). doi: 10.1093/femsec/fiac047.
Sialic acids are a family of nine-carbon negatively charged carbohydrates. In animals, they are abundant on mucosa surfaces as terminal carbohydrates of mucin glycoproteins. Some commensal and pathogenic bacteria are able to release, take up and catabolize sialic acids. Recently, sialic acids have been discovered to be widespread among most microorganisms. Although the catabolism of sialic acids has been intensively investigated in the field of host-microbe interactions, very limited information is available on microbial degradation of sialic acids produced by environmental microorganisms. In this study, the catabolic pathways of sialic acids within a microbial community dominated by 'Candidatus Accumulibacter' were evaluated. Protein alignment tools were used to detect the presence of the different proteins involved in the utilization of sialic acids in the flanking populations detected by 16S rRNA gene amplicon sequencing. The results showed the ability of Clostridium to release sialic acids from the glycan chains by the action of a sialidase. Clostridium and Chryseobacterium can take up free sialic acids and utilize them as nutrient. Interestingly, these results display similarities with the catabolism of sialic acids by the gut microbiota. This study points at the importance of sialic acids in environmental communities in the absence of eukaryotic hosts.
唾液酸是一族九碳带负电荷的碳水化合物。在动物中，它们作为黏蛋白糖蛋白的末端碳水化合物大量存在于黏膜表面。一些共生菌和致病菌能够释放、摄取和分解唾液酸。最近，人们发现唾液酸在大多数微生物中广泛存在。尽管在宿主-微生物相互作用领域中对唾液酸的代谢进行了深入研究，但关于环境微生物产生的唾液酸的微生物降解的信息非常有限。在本研究中，评估了以“Accumulibacter 菌”为主导的微生物群落中唾液酸的代谢途径。通过使用蛋白质比对工具，检测了在 16S rRNA 基因扩增子测序检测到的侧翼种群中参与利用唾液酸的不同蛋白质的存在。结果表明，梭菌通过唾液酸酶的作用从聚糖链中释放唾液酸的能力。梭菌和金杆菌可以摄取游离的唾液酸并将其用作营养物质。有趣的是，这些结果与肠道微生物群分解唾液酸的代谢过程具有相似性。本研究指出了在没有真核宿主的情况下，唾液酸在环境群落中的重要性。
