Department of Veterinary Public Health, Faculty of Veterinary Medicine, University of Bari, Valenzano, Bari, Italy.
Med Mycol. 2010 Feb;48(1):73-8. doi: 10.3109/13693780902718347.
Malassezia spp. may act as opportunistic skin pathogens in humans and animals. Malassezia pachydermatis proliferation and phospholipase production may play a pathogenic role in the occurrence of skin lesions in dogs. This study investigates the presence of mu-opioid receptor (MOR) in M. pachydermatis strains isolated from healthy dogs and dogs with skin lesions and its effects on phospholipase activity (p.a.). P.a. of 64 M. pachydermatis isolates was evaluated using different concentrations of naloxone (Nx), a MOR antagonist. Isolates were divided into Group A (i.e., 40 isolates from 26 dogs with dermatitis) and Group B (i.e., 24 isolates from 12 healthy dogs). The MOR expression was analyzed by Western blot and immunofluorescence. A statistically higher p.a. than that of the controls was found with isolates in Group A at a Nx concentration of 10(-6) M (P<0.05). No isolate in Group B displayed p.a. in either control samples or in the presence of any Nx concentration. Immunoblotting revealed two positive MOR immunoreactive bands of approximately 65 and 98 kDa. MOR expression and localization was also demonstrated by immunofluorescence in isolates from Groups A and B. This study provides the first evidence of MOR expression on M. pachydermatis cell membranes pointing to its possible role in modulating p.a. production in isolates from dogs with skin lesions.
马拉色菌属可作为人和动物的机会性皮肤病原体。糠秕马拉色菌的增殖和磷脂酶的产生可能在犬皮肤损伤的发生中发挥致病作用。本研究调查了健康犬和有皮肤损伤的犬分离的糠秕马拉色菌菌株中存在的μ-阿片受体（MOR）及其对磷脂酶活性（p.a.）的影响。使用不同浓度的纳洛酮（Nx），一种 MOR 拮抗剂，评估了 64 株糠秕马拉色菌分离株的 p.a.。将分离株分为 A 组（即 26 只患有皮炎的犬的 40 株分离株）和 B 组（即 12 只健康犬的 24 株分离株）。通过 Western blot 和免疫荧光分析 MOR 表达。在 Nx 浓度为 10(-6) M 时，A 组分离株的 p.a.明显高于对照组（P<0.05）。B 组中没有分离株在任何 Nx 浓度下在对照样本中或存在时显示出 p.a.。免疫印迹显示约 65 和 98 kDa 的两个阳性 MOR 免疫反应性带。A 组和 B 组分离株的免疫荧光也显示了 MOR 的表达和定位。本研究首次提供了糠秕马拉色菌细胞膜上存在 MOR 表达的证据，表明其在调节皮肤损伤犬分离株的 p.a.产生中可能发挥作用。
