Merçot Herve, Defaye Danielle, Capy Pierre, Pla Eliane, David Jean R
Institut Jacques Monod, Laboratoire Dynamique du Génome et Evolution. Tour 42-4. CNRS - Université Paris 7, 2 Place Jussieu, 75251, Paris, France.
Muséum National d'Histoire Naturelle, Laboratoire de Zoologie des Arthropodes. 61 Rue Buffon, 75005, Paris, France.
Evolution. 1994 Jun;48(3):746-757. doi: 10.1111/j.1558-5646.1994.tb01358.x.
In vitro alcohol dehydrogenase (ADH) activity was measured in adults of species belonging to Drosophila and to the related genus Zaprionus. Data were analyzed according to the known breeding sites and the level of ethanol tolerance of these species. Alcohol dehydrogenase activity was assayed with both ethanol (E) and isopropanol (I). Our results show a very broad range of activities among the 71 species investigated, the ratio of the highest value observed (D. melanogaster) to the lowest (D. pruinosa) being 65:1. A general positive correlation was found between the level of ADH activity and the capacity to detoxify ethanol. Nevertheless, many species show exceptions to this rule. Contrary to a logical expectation, adaptation to high alcoholic resources, which has been a recurrent evolutionary event, was not mediated by a more efficient use of ethanol, that is, an increase of the E/I ratio. This ratio seems to be quite variable according to the phylogeny and is especially low in the subgenus Sophophora as well as in Zaprionus. Alcohol tolerance clearly is related to the larval habitat of the species and shows that adaptation to alcoholic resources has been a major evolutionary challenge in drosophilids. This adaptation is not related to phylogeny, having occurred independently several times during the evolution of the group. Finally, it should be borne in mind that, besides metabolization and detoxification, other physiological processes such as nervous-system tolerance or ethanol excretion may be involved in ethanol tolerance, and such functions also should be investigated. Environmental ethanol, which is certainly a major ecological parameter for many drosophilids, has selected a diversity of physiological adaptations, all related to the Adh locus, but presumably much more complicated than was previously believed.
在属于果蝇属及相关的扎普里昂果蝇属的物种成虫中测量了体外乙醇脱氢酶（ADH）活性。根据这些物种已知的繁殖地点和乙醇耐受性水平对数据进行了分析。用乙醇（E）和异丙醇（I）测定了乙醇脱氢酶活性。我们的结果显示，在所研究的71个物种中，活性范围非常广泛，观察到的最高值（黑腹果蝇）与最低值（粉腹果蝇）之比为65:1。发现ADH活性水平与乙醇解毒能力之间存在普遍的正相关。然而，许多物种都有此规则的例外情况。与合理预期相反，适应高酒精资源这一反复出现的进化事件，并非由对乙醇更有效的利用（即E/I比值的增加）介导。根据系统发育，这个比值似乎相当可变，在Sophophora亚属以及扎普里昂果蝇属中尤其低。乙醇耐受性显然与物种的幼虫栖息地有关，表明适应酒精资源一直是果蝇科动物面临的主要进化挑战。这种适应与系统发育无关，在该类群的进化过程中独立发生了几次。最后，应该记住，除了代谢和解毒之外，其他生理过程，如神经系统耐受性或乙醇排泄，可能也参与了乙醇耐受性，这些功能也应该进行研究。环境乙醇肯定是许多果蝇科动物的一个主要生态参数，它选择了多种生理适应，所有这些适应都与Adh基因座有关，但可能比以前认为的要复杂得多。
