Toxocariasis is a zoonotic disease affecting humans that is predominantly caused by Toxocara canis and T. cati, primarily parasites of dogs and cats, respectively. Toxocara generally establishes long-term infections by co-opting its host’s physiological processes, while at the same time exploiting the nutritional environment. Adult stage T. canis reside in the gut of the definitive canine host where they employ a suite of strategies to combat intestinal immune responses by actively producing and releasing excretory-secretory products (ESPs). The protein component of T. canis ESPs has been widely studied, but characterisation of the non-protein ESP complement remains neglected. To characterize the secreted metabolome of Toxocara ESPs and to shed light on the parasite’s metabolic processes, we profiled the ESPs of T. canis using both gas chromatography (GC) and liquid chromatography (LC) mass spectrometry approaches. We successfully identified 61 small molecules, including 41 polar metabolites, 14 medium-long chain fatty acids (MLCFAs) and six short chain fatty acids (SCFAs). We identified talose, stearic acid and isovalerate as the major compounds belonging to the polar, MLCFA and SCFA chemical classes, respectively. Most of the 61 identified metabolites appear to have been produced by T. canis via three distinct metabolic pathways - fatty acid, amino acid and carbohydrate metabolism. The majority of the identified ESPs have known biological properties, especially as immunomodulators. However, there is limited/no information on the biological roles or applications of 31 ESP biomolecules, suggesting that these may have novel activities that merit further investigation.

中文翻译：

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人畜共患的Round虫寄生犬弓形虫的排泄/分泌代谢组。

弓形虫病是一种影响人的人畜共患疾病，主要由犬Toxocara canis和T. cati引起，分别是狗和猫的寄生虫。弓形虫一般通过选择宿主的生理过程来建立长期感染，同时利用营养环境。成年T. canis犬位于定型犬宿主的肠道中，在那里他们采用一系列策略来通过主动产生和释放排泄-分泌产物（ESP）来对抗肠道免疫反应。犬圆弧菌的蛋白质成分ESPs已被广泛研究，但非蛋白质ESP补体的表征仍被忽略。为了表征Toxocara ESP的分泌代谢组并阐明寄生虫的代谢过程，我们使用气相色谱（GC）和液相色谱（LC）质谱分析方法对犬链球菌的ESP进行了分析。我们成功鉴定出61个小分子，包括41个极性代谢物，14个中长链脂肪酸（MLCFA）和6个短链脂肪酸（SCFA）。我们确定了塔洛糖，硬脂酸和异戊酸酯是分别属于极性，MLCFA和SCFA化学类别的主要化合物。在61种鉴定出的代谢产物中，大多数似乎是由犬圆弧菌产生的。通过三种不同的代谢途径-脂肪酸，氨基酸和碳水化合物的代谢。大多数鉴定出的ESP具有已知的生物学特性，尤其是作为免疫调节剂。然而，关于31种ESP生物分子的生物学作用或应用的信息有限/尚无资料，这表明它们可能具有值得进一步研究的新颖活性。