经腹腔注射回归热螺旋体感染树鼩后,每日采血计数螺旋体数,记录树鼩临床症状和体温变化;试验后期解剖树鼩取其脏器,进行组织病理分析,探讨回归热螺旋体感染树鼩后引起的变化.结果 表明:回归热螺旋体在树鼩体内能有效地增殖,感染后7d左右会出现第1个菌血症高峰,而后开始下降,感染后12～14 d又形成1个峰,最终形成1个“回归”状增殖曲线;体温与未感染树鼩一样,无明显变化,但死亡前会骤降2～10℃;树鼩感染螺旋体后出现双后肢及尾无力等神经症状;剖检及组织病理学分析发现,螺旋体感染造成树鼩肝脏和脾脏内严重炎症,引起树鼩肝脏和脾脏明显肿大,约为正常树鼩的2倍;回归热螺旋体能有效感染树鼩,形成回归状菌血症,并可引起树鼩神经症状.这一研究提示树鼩可作为研究回归热螺旋体感染和致病机制的动物模型.

Herbs derived from roots, leaves, flowers, or fruits of plants are unavoidably contaminated with fungi and mycotoxins during growth, harvest, and storage, thereby posing a health threat to humans. Especially, root herbs (RHs) are more easily contaminated with fungi and mycotoxins because the roots are in direct contact with the soil. Here, we investigated the occurrence of fungi, aflatoxins (AFs), and ochratoxin A (OTA) in eight RHs that are used as medicines, beverages, dietary supplements, and functional foods in China and other countries. Morphological observation and MultiGeneBlast (β-tubulin and calmodulin) were used to identify the potentially toxigenic fungi. Of the 48 samples tested, all were contaminated by fungi, and 1,844 isolates belonging to 25 genera were detected. The genera Aspergillus and Penicillium, which contain potentially toxigenic fungal species, represented a frequency of 10 and 25%, respectively. Thirty-three isolates of Aspergillus flavus, Aspergillus parasiticus, Aspergillus niger, and Penicillium polonicum were arbitrarily selected for analysis of their toxigenic potential. Five of 13 isolates of A. flavus and 1 isolate of A. parasiticus produced AFs, whereas OTA production was not detected for any of the isolates of A. niger and P. polonicum. The occurrence of AFs and OTA in the 48 samples of eight RHs was tested by ultraperformance liquid chromatography-tandem mass spectrometry; 37.50% of samples from six RHs were contaminated with AFs and 16.67% of samples from four RHs were contaminated with OTA. Seven (14.58%) and four (8.33%) samples of ginseng, polygala, and liquorice exceeded the permissible limits of aflatoxin B1 and AFs, respectively. Because ginseng, polygala, and liquorice are widely used as herbs, dietary supplements, and functional foods, the high frequency of AF contamination of these herbs indicated by our current study warrant attention to raise public awareness.

Objective:To obtain the optimal condition of isolation method of contamination fungi from medicinal herbs,and compare the contaminated fungi on Panax pseudoginseng,Astragalus membranaceus,and Codonopsis pilosula.Methods:According to the orthogonaltest L9(34),the effect of four factors including herb species (A),shaking speed (B),shaking time (C) and medium (D) on the fungal counts of total fungi,Aspergillus and Penicillium were measured by using the dilution plating methodAll isolates of Aspergillus and Penicillium were identified based on morphological criteria using macro-and micro-charactersThe root samples were further tested for aflatoxins using UPLC-MS/MSResults:The optimal isolation method for both total fungi and Aspergillus was 130 r·min-1 of shaking speed,15 min of shaking time,and YES mediumThe optimal isolation method for Penicillium was 160 r·min-1 of shaking speed,30 min of shaking time,and PDA mediumThe fungal count of total fungi on Cpilosula was higher than that of the other two root medicinal herbsMoreover,the fungal count of Aspergillus on three root medicinal herbs were higher than that of PenicilliumWith respect of aflatoxins occurrence,Amembranaceus was contaminated with AFB1 at concentration of 454 μg·kg-1,while no AFs were detected from Ppseudoginseng and CpilosulaConclusion:The isolation method affected fungi isolation resultsThe contamination of three herbs with Aspergillus should be paid more attention.