Gut-based antioxidant enzymes in a polyphagous and a graminivorous grasshopper
Gut-based antioxidant enzymes in a polyphagous and a graminivorous grasshopper
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DOI：
10.1023/a:1016288201110
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发表时间：
2002-07-01
影响因子：
2.3
通讯作者：
Barbehenn, RV
中科院分区：
文献类型：
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作者：
Barbehenn, RV
草食性蝗虫在摄入单宁酸时会在中肠上皮细胞中产生致命的损伤，而多食性蝗虫则不受摄入单宁酸的影响。这项研究测试的假设，即多食性物种捍卫了更高的抗氧化酶（组成型或诱导型）在他们的肠道比草食性物种的活动。比较了四种抗氧化酶：超氧化物歧化酶（SOD），过氧化氢酶（CAT），抗坏血酸过氧化物酶（APOX），谷胱甘肽转移酶过氧化物酶（GSTPX）。本文测定了多食性的血足黑丽鱼和草食性的艾氏管丽鱼的肠腔和中肠组织中的酶活性。本研究结果不支持M.抗氧化酶能更好地保护血足类植物。ellioti，也不是这些酶在M. sanguinipes比A.当昆虫食用含有15%干重单宁酸的食物时，相反，单宁酸消耗减少SOD，APOX，GSTPX的活动在这两个物种。这项研究报告了第一个证据，即SOD分泌到昆虫中肠腔，活性比中肠组织中的活性高出两到四倍。在这两个物种中观察到的GSTPX和APOX活性的空间分布表明，摄入的植物抗氧化酶可能作为获得防御蝗虫。此外，本研究的结果首次比较了直翅目和鳞翅目的抗氧化酶防御作用。最值得注意的是，蚱蜢的SOD活性比毛虫高，但在它们的中肠组织中完全缺乏APOX。
Graminivorous species of grasshoppers develop lethal lesions in their midgut epithelia when they ingest tannic acid, whereas polyphagous grasshoppers are unaffected by ingested tannins. This study tests the hypothesis that polyphagous species are defended by higher activities of antioxidant enzymes (constitutive or inducible) in their guts than are graminivorous species. Comparisons were made between four antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APOX), and glutathione transferase peroxidase (GSTPX). Enzyme activities were measured in the gut lumens and midgut tissues of Melanoplus sanguinipes (polyphagous) and Aulocara ellioti (graminivorous). The results of this study do not support the hypothesis that M. sanguinipes is better defended by antioxidant enzymes than is A. ellioti, nor are these enzymes more inducible in M. sanguinipes than in A. ellioti when insects consume food containing 15% dry weight tannic acid. Instead, tannic acid consumption reduced SOD, APOX, and GSTPX activities in both species. This study reports the first evidence that SOD is secreted into the midgut lumen in insects, with activities two- to fourfold higher than those found in midgut tissues. The spatial distribution of GSTPX and APOX activities observed in both species suggests that ingested plant antioxidant enzymes may function as acquired defenses in grasshoppers. In addition, the results of this study permit the first comparison between the antioxidant enzyme defenses of Orthoptera and Lepidoptera. Most notably, grasshoppers have higher SOD activities than caterpillars, but completely lack APOX in their midgut tissues.