This study evaluates peptidoglycan hydrolysis by a microbial muramidase from the fungus Acremonium alcalophilum in vitro and in the gastrointestinal tract of broiler chickens. Peptidoglycan used for in vitro studies was derived from 5 gram-positive chicken gut isolate type strains. In vitro peptidoglycan hydrolysis was studied by three approaches: (a) helium ion microscopy to identify visual phenotypes of hydrolysis, (b) reducing end assay to quantify solubilization of peptidoglycan fragments, and (c) mass spectroscopy to estimate relative abundances of soluble substrates and reaction products. Visual effects of peptidoglycan hydrolysis could be observed by helium ion microscopy and the increase in abundance of soluble peptidoglycan due to hydrolysis was quantified by a reducing end assay. Mass spectroscopy confirmed the release of hydrolysis products and identified muropeptides from the five different peptidoglycan sources. Peptidoglycan hydrolysis in chicken crop, jejunum, and caecum samples was measured by quantifying the total and soluble muramic acid content. A significant increase in the proportion of the soluble muramic acid was observed in all three segments upon inclusion of the microbial muramidase in the diet.

中文翻译：

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在肉鸡胃肠道中发现的 Acremonium alcalophilum 的胞壁质酶水解肽聚糖

本研究评估了来自真菌 Acremonium alcalophilum 的微生物胞壁质酶在体外和肉鸡胃肠道中对肽聚糖的水解作用。用于体外研究的肽聚糖来自 5 克阳性鸡肠道分离株。通过三种方法研究体外肽聚糖水解：（a）氦离子显微镜鉴定水解的视觉表型，（b）减少末端测定以量化肽聚糖片段的溶解度，以及（c）质谱估计可溶性底物的相对丰度和反应产物。肽聚糖水解的视觉效果可以通过氦离子显微镜观察到，并且由于水解导致的可溶性肽聚糖的丰度增加通过还原末端测定来量化。质谱证实了水解产物的释放，并从五种不同的肽聚糖来源中鉴定了鼠肽。通过量化总的和可溶性胞壁酸含量来测量鸡作物、空肠和盲肠样品中的肽聚糖水解。在饮食中加入微生物胞壁酸酶后，在所有三个部分中都观察到可溶性胞壁酸的比例显着增加。