CAJ | 학술논문

低温生长的适应是一个复杂的过程，涉及细胞的分子生物学和生物化学等很多方面．前期的研究表明，产油真菌———深黄被孢霉（Mortierella isabellina）M6－22能在5～35℃的温度范围生长．本研究以其为研究对象，分析温度下降引起的 M6－22细胞膜流动性、多不饱和脂肪酸含量以及多不饱和脂肪酸合成相关基因的 mRNA 转录水平的变化．结果显示，在15℃条件下，M6－22的细胞膜流动性明显降低，而多不饱和脂肪酸含量显著提高，由30℃时20．85％增加到15℃时的31．04％，而且15℃时Δ12－脂肪酸脱氢酶基因 mRNA 转录水平提高了近3倍，但是Δ6－脂肪酸脱氢酶基因 mRNA 转录水平基本不变．这些研究结果表明，深黄被孢霉 M6－22可能通过提高Δ12－脂肪酸脱氢酶基因的表达水平，增加膜脂中多不饱和脂肪酸含量，维持低温条件下细胞膜的流动性来促进细胞低温环境的适应．本研究将为研究低温条件下多不饱和脂肪酸合成调节机制以及进一步多不饱和脂肪酸工业化生产打下基础．
저온생장적괄응시일개복잡적과정，섭급세포적분자생물학화생물화학등흔다방면．전기적연구표명，산유진균———심황피포매（Mortierella isabellina）M6－22능재5～35℃적온도범위생장．본연구이기위연구대상，분석온도하강인기적 M6－22세포막류동성、다불포화지방산함량이급다불포화지방산합성상관기인적 mRNA 전록수평적변화．결과현시，재15℃조건하，M6－22적세포막류동성명현강저，이다불포화지방산함량현저제고，유30℃시20．85％증가도15℃시적31．04％，이차15℃시Δ12－지방산탈경매기인 mRNA 전록수평제고료근3배，단시Δ6－지방산탈경매기인 mRNA 전록수평기본불변．저사연구결과표명，심황피포매 M6－22가능통과제고Δ12－지방산탈경매기인적표체수평，증가막지중다불포화지방산함량，유지저온조건하세포막적류동성래촉진세포저온배경적괄응．본연구장위연구저온조건하다불포화지방산합성조절궤제이급진일보다불포화지방산공업화생산타하기출．
Adaptation to low -temperature growth is complex,involving many aspects of the molecular biology and biochemistry of the cell.Our previous study has indicated that Mortierella isabellina strain M6 -22,an ole-aginous fungus,is able to sustain growth at temperatures ranging from 5℃ to 35℃.In this study,the changes in cell membrane fluidity,content of polyunsaturated fatty acids and mRNA expression levels of desaturase genes of M6 -22 in response to temperature downshift is analyzed.The results show that the membrane fluidity of M6 -22 is significantly reduced when the culture temperature decreases from 30℃ to 15℃,but the content of polyun-saturated fatty acids including linoleic acid and γ-Linolenic acid increases significantly from 20.85% to 31.04%.Furthermore,the mRNA transcription level of Δ12 -desaturase gene is about 3 -fold higher in M6 -22 grown at 15℃ than in those grown at 30℃,but the mRNA transcription level of Δ6 -desaturase gene does not change significantly with the downshift of temperature.These results indicate that reduced membrane fluidity at low temperature induces higher genes expression of polyunsaturated fatty acids biosynthesis,which might result in higher content of polyunsaturated fatty acids accumulated in M6 -22 to maintain the membrane fluidity at low temperature and enhance its cold adaptation.This study will provide a basis for exploring the regulation mecha-nisms of polyunsaturated fatty acids biosynthesis at low temperature and further industrial application for PUFAs production.