Muryoi Naomi, Kawahara Hidehisa, Obata Hitoshi
Department of Biotechnology, Faculty of Engineering, Kansai University, Suita-shi, Osaka, Japan.
Biosci Biotechnol Biochem. 2003 Sep;67(9):1950-8. doi: 10.1271/bbb.67.1950.
Some ice-nucleating bacterial strains, including Pantoea ananatis (Erwinia uredovora), Pseudomonas fluorescens, and Pseudomonas syringae isolates, were examined for the ability to shed ice nuclei into the growth medium. A novel ice-nucleating bacterium, Pseudomonas antarctica IN-74, was isolated from Ross Island, Antarctica. Cell-free ice nuclei from P. antarctica IN-74 were different from the conventional cell-free ice nuclei and showed a unique characterization. Cell-free ice nuclei were purified by centrifugation, filtration (0.45 microm), ultrafiltration, and gel filtration. In an ice-nucleating medium in 1 liter of cell culture, maximum growth was obtained with the production of 1.9 mg of cell-free ice nuclei. Ice nucleation activity in these cell-free ice nuclei preparations was extremely sensitive to pH. It was demonstrated that the components of cell-free ice nuclei were protein (33%), saccharide (12%), and lipid (55%), indicating that cell-free ice nuclei were lipoglycoproteins. Also, carbohydrate and lipid stains showed that cell-free ice nuclei contained both carbohydrate and lipid moieties.
研究了一些冰核细菌菌株，包括菠萝泛菌（草生欧文氏菌）、荧光假单胞菌和丁香假单胞菌分离株，检测它们向生长培养基中释放冰核的能力。从南极罗斯岛分离出一种新型冰核细菌——南极假单胞菌IN-74。南极假单胞菌IN-74的无细胞冰核与传统的无细胞冰核不同，并表现出独特的特性。通过离心、过滤（0.45微米）、超滤和凝胶过滤对无细胞冰核进行纯化。在1升细胞培养物的冰核培养基中，产生1.9毫克无细胞冰核时获得最大生长量。这些无细胞冰核制剂中的冰核活性对pH极为敏感。结果表明，无细胞冰核的成分是蛋白质（33%）、糖类（12%）和脂质（55%），这表明无细胞冰核是脂蛋白糖。此外，碳水化合物和脂质染色显示无细胞冰核同时含有碳水化合物和脂质部分。
