Paenibacillus larvae is a Gram-positive bacterium, the spores of which are the causative agent of the most destructive brood disease of honeybees, American foulbrood (AFB). Obtaining viable spores of pathogen strains is requisite for different studies concerning AFB. The aim of this work was to investigate the effects of five saccharides that may naturally occur in higher amounts in bee larvae on in vitro sporulation of P. larvae. The effect of individual saccharides at different concentrations on spore yields of P. larvae strains of epidemiologically important ERIC genotypes was examined in Columbia sheep blood agar (CSA) and MYPGP agar media. It was found that fructose in ERIC I and trehalose in ERIC II strains at concentrations in the range of 0.5–2% represent new sporulation factors that significantly enhanced the yields of viable spores in both media, mostly in a concentration-dependent manner. The enhancements in spore yield were mainly caused by improvements of the germination ability of the spores produced. Glucose, maltose and sucrose at 1% or 0.5% concentrations also supported sporulation but to a lower extent and not in all strains and media. Based on the knowledge gained, a novel procedure was proposed for the preparation of viable P. larvae spores with supposed improved quality for AFB research.

中文翻译：

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果糖和海藻糖选择性增强类芽孢杆菌幼虫 ERIC I 和 ERIC II 菌株的体外孢子形成


类芽孢杆菌幼虫是一种革兰氏阳性细菌，其孢子是蜜蜂最具破坏性的巢病——美国幼虫腐臭病（AFB）的病原体。获得病原体菌株的活孢子对于 AFB 的不同研究是必要的。这项工作的目的是研究蜜蜂幼虫中天然含量较高的五种糖对蜜蜂幼虫体外产孢的影响。在哥伦比亚绵羊血琼脂 (CSA) 和 MYPGP 琼脂培养基中检查了不同浓度的单个糖对流行病学上重要的 ERIC 基因型的P. 幼虫菌株孢子产量的影响。研究发现，ERIC I 中的果糖和 ERIC II 菌株中的海藻糖浓度在 0.5-2% 范围内时代表了新的孢子形成因子，可显着提高两种培养基中活孢子的产量，主要以浓度依赖性方式。孢子产量的提高主要是由于所产生的孢子的萌发能力的提高所致。 1% 或 0.5% 浓度的葡萄糖、麦芽糖和蔗糖也支持孢子形成，但程度较低，并且并非在所有菌株和培养基中都支持。根据所获得的知识，提出了一种新的程序来制备活的P. 幼虫孢子，并假定可以提高 AFB 研究的质量。