Novel surfactant proteins are involved in the structure and stability of foam nests from the frog Leptodactylus vastus
Novel surfactant proteins are involved in the structure and stability of foam nests from the frog Leptodactylus vastus
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DOI：
10.1242/jeb.019315
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发表时间：
2008-08-15
影响因子：
2.8
通讯作者：
Maciel Melo, Vania Maria
中科院分区：
文献类型：
--
作者：
Hissa, Denise Cavalcante;Vasconcelos, Ilka Maria;Maciel Melo, Vania Maria
许多两栖动物将卵产在泡沫巢中，这样卵就可以沉积在水中。对其中一些泡沫巢的分析表明，它们是蛋白质的丰富来源，具有不寻常的一级结构和显着的表面活性剂活性，被命名为“ranaspumins”。这项工作的目的是研究青蛙 Leptodactylus badus 的泡沫巢，以获得有关其组成和功能的信息，并提高对雷纳斯普明（可能是一类新型表面活性剂蛋白）的了解。对泡沫液成分的分析表明，蛋白质和碳水化合物可能为发育中的蝌蚪提供营养。对泡沫液在化学防御中的功能的研究表明，没有与公认的防御化合物相关的显着生物活性。然而，泡沫液呈现出紫外线吸收性，表明其具有防止阳光损伤的作用，这被认为是最近报道的两栖动物种群数量下降的可能原因之一。泡沫巢不能阻止微生物的定植，例如观察到的以革兰氏阳性杆菌为主的细菌群落。 L.vantus 泡沫液显示出与其蛋白质相关的强表面活性剂活性，这种活性似乎主要归因于一种名为 Lv-ranaspumin 的蛋白质。通过离子交换色谱法分离该蛋白质，发现其是具有以下 N 末端序列的 20 kDa 单体分子：FLEGFLVPKVVPGPTAALLKKALDD。这种蛋白质与已知的蛋白质或结构没有任何匹配，这表明它属于一类新的表面活性剂蛋白质。
Many amphibians lay their eggs in foam nests, which allow the eggs to be deposited out of the water. Analysis of some of these foam nests has revealed that they are a rich source of proteins with unusual primary structures and remarkable surfactant activity, named ranaspumins. The aim of this work was to study the foam nests of the frog Leptodactylus vastus in order to obtain information regarding their composition and function and to improve the understanding of ranaspumins, which are probably a novel class of surfactant proteins. Analyses of the foam fluid composition showed proteins and carbohydrates that presumably are responsible for providing nutrients for the developing tadpoles. Investigation of the function of foam fluid in chemical defence revealed no significant biological activity that could be associated with recognized defence compounds. However, foam fluid presented UV absorbance, suggesting a role in protection against sun damage, which is considered to be one of the possible causes of recently reported amphibian population declines. The foam nests do not prevent the colonization of microorganisms, such as the observed bacterial community of predominantly Gram-positive bacilli. L. vastus foam fluid shows a strong surfactant activity that was associated with their proteins and this activity seems to be due mainly to a protein named Lv-ranaspumin. This protein was isolated by ion-exchange chromatography and found to be a 20 kDa monomeric molecule with the following N-terminal sequence: FLEGFLVPKVVPGPTAALLKKALDD. This protein did not show any match to known proteins or structures, which suggests that it belongs to a new class of surfactant protein.