熱效應對綠球藻蛋白質合成之影響

Abstract

綠球藻以16小時照光（光度6000 Lx），8小時黑暗之週期，於25?C下進行同步培養。於每次照光前，將細胞濃度稀釋為每毫升含5×10^6個細胞。 木實驗選出二個時期，觀察熱處理對綠球藻蛋白質合成類型之影響。時期Ⅰ為開始照光後，第５小時之細胞（生長期的細胞），時期Ⅱ為第14.5小時約細胞（成熟期的細胞）。此二時期之綠球藻，分別任42.５?Ｃ振盪培養3小時，以3H-leucine標示合成之蛋白質。經10% SDS-polyacrylamide廖體電泳分析，及自動放射顯影，結果顯示：熱處理改變綠球藻蛋質之合成類型，對二個不同之時期有相同的影響。即減少或停止正常蛋白質之合成；合成相同之熱效應蛋白質。其分子量，分別是94, 000, 84, 000, 81, 000, 77, 000, 26000及17, 000 daltons若以12.5%膠體分析，則二個小分子均可細分為二個橫帶。時期Ⅰ之藻細胞，在42.5?C處理3小時後，再移至30?C，經1?2小時後，蛋白質合成類型即能回復正常。

Synchronous Chlorella cultures were obtained by alternating a light prtiod of 16 hr and a dark period of 8 hr at 25 ?C at 25?C and by diluting to 5x10^6 cells/ml at the end of each dark period. Synchronously cultured Chlorells were treated with temperature up to 42.5?C for 3 hr both at the 5th hour (stage I) and at 14.5 th hour (stage II) after the begining of the light period. During the treatment the cells were labeled with 3H-leucine, Labeled proteins were analyzed by SDS-polyacrylamide gel electrophoresis and fluorography. （ ）and reducing the synthesis of normal proteins. The molecular weights of heat shock proteins were 94,000, 84,000, 77,000, 26,000, and 17,000 daltons. When the Chlorella cells at stage I were returmed to 30?C after 3 hr at 42.5?C, there were a decline in the synthesis of heat shock proteins and a reappearance of a normal pattern of protein synthesis by 1 or 2 hr, however, Chlorella cells recovered to divied after 2 photoperiodical cycles.