Hazeleger Wilma C, Dalvoorde Marinka, Beumer Rijkelt R
Laboratory of Food Microbiology, Wageningen University, 6700 EV Wageningen, The Netherlands.
Int J Food Microbiol. 2006 Dec 1;112(3):288-90. doi: 10.1016/j.ijfoodmicro.2006.04.026. Epub 2006 Jun 27.
The cell morphology of Salmonella enteritidis and Listeria monocytogenes after the application of stress was examined. Cells were stressed by plating the bacteria on Tryptone Soya Agar (TSA) plates, with 5-10% NaCl. The plates were subsequently incubated for 6 days at 25 degrees C. Finally, the cells were harvested and subjected to different fluorescent probes in order to visualize the possible presence of septa in elongated cells. Use of the stain 4',6-Diamidino-2-phenylindole (DAPI), which is a blue fluorescent nucleic acid stain that preferentially stains double-stranded DNA, showed clearly the presence of dark spots, probably cellular partitions where no nucleic acids were present, in both Salmonella and Listeria cells. Another stain, FM 4-64, a lipophilic styryl dye for red staining of the inner membrane, showed the presence of highly fluorescent spots in Listeria cells, probably indicating the presence of membranes. For Salmonella, however, FM 4-64 was not successful in revealing septa in filaments. Double staining applied to elongated Listeria cells showed areas with high fluorescence in DAPI-staining (DNA-rich spots) which contained low fluorescence in FM 4-64-staining (membrane spots) and vice versa, which is a confirmation that the elongated cells are indeed composed of several normal size cells.
研究了施加应激后肠炎沙门氏菌和单核细胞增生李斯特菌的细胞形态。通过将细菌接种在含有5 - 10%氯化钠的胰蛋白胨大豆琼脂（TSA）平板上对细胞施加应激。随后将平板在25摄氏度下孵育6天。最后，收获细胞并使用不同的荧光探针，以观察伸长细胞中是否可能存在隔膜。使用4',6-二脒基-2-苯基吲哚（DAPI）染色，它是一种蓝色荧光核酸染料，优先染色双链DNA，清楚地显示了沙门氏菌和李斯特菌细胞中存在暗斑，这些暗斑可能是不存在核酸的细胞间隔。另一种染料FM 4-64，一种用于内膜红色染色的亲脂性苯乙烯基染料，显示李斯特菌细胞中存在高荧光斑点，这可能表明存在膜。然而，对于沙门氏菌，FM 4-64未能成功揭示丝状菌中的隔膜。对伸长的李斯特菌细胞进行双重染色显示，在DAPI染色（富含DNA的斑点）中荧光高的区域在FM 4-64染色（膜斑点）中荧光低，反之亦然，这证实了伸长的细胞确实由几个正常大小的细胞组成。
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