In vitro susceptibility of Candida species to lactoferrin.
In vitro susceptibility of Candida species to lactoferrin.
复制标题
念珠菌属对乳铁蛋白的体外敏感性。
作者：
Y. Y. Xu;Y. Samaranayake;L. Samaranayake;H. Nikawa
乳铁蛋白是一种存在于人类粘膜分泌物和唾液中的抗菌蛋白。由于没有关于人乳铁蛋白和牛乳铁蛋白相对杀真菌活性的资料，我们研究了一株口服白色念珠菌对这两种蛋白的敏感性。无论孵育时间是45分钟、90分钟还是150分钟，在37摄氏度下暴露于浓度为20微克ml-1的HLF或BLF中，酵母的失活程度都是相同的。在一项类似的研究中，使用20微克ml-1 BLF和150分钟的孵育时间，对属于6种不同念珠菌的35株菌株产生了不同的抗念珠菌活性。因此，BLF对6种念珠菌的抑菌效果由大到小依次为：热带念珠菌b>克氏念珠菌b>白色念珠菌b>吉列念珠菌b>副念珠菌b>光秃秃念珠菌；后者的抵抗力最强。这些念珠菌对该蛋白的易感性在种内也存在显著差异（P < 0.05）。当暴露于BLF的酵母细胞通过冷冻扫描电镜检查时，可以注意到深刻的细胞壁变化，如细胞表面起泡，肿胀和细胞塌陷。这些发现表明，乳铁蛋白，唾液的一个组成部分，可能会不同地调节口腔中念珠菌的携带。
Lactoferrin is an antimicrobial protein present in human mucosal secretions as well as saliva. As there is no information on the relative fungicidal activity of human and bovine lactoferrin, an oral isolate of Candida albicans was studied for its susceptibility to these two proteins. Exposure to a concentration of 20 micrograms ml-1 of either HLF or BLF at 37 degrees C inactivated the yeast to the same degree irrespective of the incubation time of 45, 90 or 150 min. A similar study, using 20 micrograms ml-1 BLF and an incubation time of 150 min, elicited varying anticandidal activity against 35 isolates belonging to six different Candida species. Thus, BLF was fungicidal for the six Candida species in the following decreasing order, C. tropicalis > C. krusei > C. albicans > C. guilliermondii > C. parapsilosis > C. glabrata; the latter being the most resistant. These Candida species also demonstrated significant intra-species variation in susceptibility to the protein (P < 0.05). When the yeast cells exposed to BLF were examined by cryo-scanning electron microscopy, profound cell wall changes such as cell surface blebs, swelling and cell collapse were noted. These findings suggest that lactoferrin, a constituent of saliva, may differentially modulate the carriage of Candida species in the oral cavity.