Genetic diversity of yeasts from East Ongul Island, East Antarctica and their extracellular enzymes secretion
Genetic diversity of yeasts from East Ongul Island, East Antarctica and their extracellular enzymes secretion
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DOI：
10.1007/s00300-017-2185-1
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发表时间：
2018-02-01
期刊：
影响因子：
1.7
通讯作者：
Tsuji, Masaharu
中科院分区：
文献类型：
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作者：
Tsuji, Masaharu
在低温下生长的微生物会遇到许多生长限制。然而，居住在极地地区的真菌可以在低温下生长和分解有机化合物。本研究对东 Ongul 岛酵母的生物多样性和分泌能力进行了研究，并评估了它们在 -3 至 20 A 摄氏度的温度范围内的细胞外酶活性。从东南极洲东翁古尔岛的表层土壤中总共分离出 95 株酵母菌株。根据内转录间隔区（ITS）和26S rDNA D1/D2结构域序列相似性，将这些菌株分为10属16种。所有菌株均被归类为担子菌酵母。从每个物种中选择一种代表性菌株，并评估其在-3°C至37°C之间的温度下生长的能力。还研究了菌株在 -3 至 20°C 温度范围内分泌胞外酶（脂肪酶、纤维素酶和蛋白酶）的能力。根据最佳和最高生长温度，酵母被分为嗜冷酵母和耐冷酵母。本研究中研究的所有菌株都能够在 -3 A 摄氏度和不含维生素的培养基中生长。嗜冷酵母，例如 Glaciozyma antarctica、Gl. martinii、Mrakia gelida 和 Phenoliferia glacialis 在 -3 A 摄氏度下不会分泌大量的胞外酶；相比之下，耐冷酵母 Goffeauzyma gilvescens、Holtermanniella wattica、Tausonia pullulans 和 Udeniomyces puniceus 即使在零下温度下也能分泌大量酶。这些结果表明，耐冷酵母，而不是嗜冷酵母，在东翁古尔岛近零度温度下生态系统的营养循环中发挥着重要作用。
Microbes growing at low temperatures encounter numerous growth constraints. However, fungi that inhabit polar regions can grow and decompose organic compounds at low temperatures. Research on the biodiversity and secretion ability of yeasts from East Ongul Island, and evaluation of their extracellular enzymatic activity at temperatures ranging from -3 to 20 A degrees C, was performed and described in this study. In total, 95 yeast strains were isolated from the surface soil on East Ongul Island, East Antarctica. Based on the internal transcribed spacer (ITS) region and 26S rDNA D1/D2 domain sequence similarity, these strains were classified into 10 genera and 16 species. All strains were categorized as basidiomycetous yeasts. One representative strain was selected from each species, and its ability to grow at temperatures between -3 and 37 A degrees C was evaluated. Strain abilities to secrete extracellular enzymes (lipase, cellulase, and protease) at temperatures ranging from -3 to 20 A degrees C were also investigated. Based on the optimal and maximal growth temperatures, the yeasts were classified as psychrophilic or psychrotolerant. All the strains investigated in this study were able to grow at -3 A degrees C and in vitamin-free media. Psychrophilic yeasts, such as Glaciozyma antarctica, Gl. martinii, Mrakia gelida, and Phenoliferia glacialis, did not secrete pronounced amounts of extracellular enzymes at -3 A degrees C; in contrast, the psychrotolerant yeasts Goffeauzyma gilvescens, Holtermanniella wattica, Tausonia pullulans, and Udeniomyces puniceus secreted copious amounts of enzymes, even at subzero temperatures. These results indicated that psychrotolerant yeasts, rather than psychrophilic yeasts, play important roles in the nutrient cycle in the East Ongul Island ecosystem at near-subzero temperatures.