Preisig C L, Kuć J A
Arch Biochem Biophys. 1985 Jan;236(1):379-89. doi: 10.1016/0003-9861(85)90638-1.
The dose response for elicitation of the hypersensitive reaction in potato tuber discs by arachidonic acid (AA) suggested saturation at higher concentrations. Glucans from Phytophthora infestans, inactive themselves as elicitors of the hypersensitive reaction, enhanced sesquiterpene accumulation and hypersensitive browning elicited by AA. Significant activity (seven times control values) was observed with 33 pmol AA/3.0-cm potato disc in the presence of glucans. Glucans did not affect accumulation of steroid glycoalkaloids, influence the timing or relative amounts of sesquiterpenes which accumulate, or affect recovery of AA added to potato discs. Glucans enhanced activity whether added to potato discs 18 h prior to AA, at the same time as AA, or 18 h after AA. Elicitor activity in the presence of glucans was evident with 20-carbon unsaturated fatty acids that had little or no elicitor activity in the absence of glucans. The position of double bonds had considerable influence on the specific activity of unsaturated fatty acids. The most active had a minimum of three double bonds in a methylene-interrupted series beginning with delta 5, e.g., delta 5,8,11. A delta 5 double bond conferred significant activity even if it was not part of a methylene-interrupted series. The 20-carbon chain length appeared optimal for elicitor activity. The 22-carbon chain acids had low activity, and 16- and 18-carbon acids were inactive. A free carboxyl group or easily transesterified group appeared necessary for activity. Arachidonyl alcohol had very low activity and arachidonyl cyanide was inactive. AA-containing phosphatidylcholine, lysophosphatidylcholine and monoacylglycerol were at least as active as free AA, AA-containing diacylglycerols were slightly less active than free AA, and triarachidonyl glycerol was inactive.
花生四烯酸（AA）引发马铃薯块茎切片过敏反应的剂量反应表明，在较高浓度时会出现饱和现象。来自致病疫霉的葡聚糖本身作为过敏反应的激发子无活性，但能增强AA引发的倍半萜积累和过敏褐变。在存在葡聚糖的情况下，33 pmol AA/3.0厘米马铃薯切片表现出显著活性（是对照值的7倍）。葡聚糖不影响甾体糖苷生物碱的积累，不影响积累的倍半萜的时间或相对量，也不影响添加到马铃薯切片中的AA的回收率。无论在AA添加前18小时、与AA同时还是在AA添加后18小时添加到马铃薯切片中，葡聚糖都能增强活性。在存在葡聚糖的情况下，20碳不饱和脂肪酸具有激发子活性，而在不存在葡聚糖时几乎没有或没有激发子活性。双键的位置对不饱和脂肪酸的比活性有相当大的影响。活性最高的在以δ5开始的亚甲基间断系列中至少有三个双键，例如δ5,8,11。即使δ5双键不是亚甲基间断系列的一部分，它也赋予显著活性。20碳链长度似乎是激发子活性的最佳长度。22碳链的酸活性低，16碳和18碳的酸无活性。活性似乎需要一个游离羧基或易于酯交换的基团。花生四烯醇活性非常低，花生四烯腈无活性。含AA的磷脂酰胆碱、溶血磷脂酰胆碱和单酰甘油至少与游离AA一样活跃，含AA的二酰甘油活性略低于游离AA，而三花生四烯酸甘油酯无活性。
