Campos Eldo, Moraes Jorge, Façanha Arnoldo R, Moreira Erica, Valle Denise, Abreu Leonardo, Manso Pedro P A, Nascimento Aline, Pelajo-Machado Marcelo, Lenzi Henrique, Masuda Aoi, Vaz Itabajara da Silva, Logullo Carlos
Laboratório de Química e Função de Proteínas e Peptídeos and Laboratório de Biologia Celular e Tecidual, CBB, UENF, Avenida Alberto Lamego, 2000, Horto, Campos dos Goytacazes, RJ, CEP 28015-620, Brazil.
Vet Parasitol. 2006 Jun 15;138(3-4):349-57. doi: 10.1016/j.vetpar.2006.02.004. Epub 2006 Mar 29.
The present work evaluates the kinetics of utilization of the main potential energy sources throughout the embryonic developmental stages of Boophilus microplus. The embryonic development of this arthropod is completed in 21 days. Cellularization of the blastoderm occurs on the 6th day and is rapidly followed by germ band extension and segmentation, whose first signs are visible on the 7th day. Cellularization is typically a maternal-driven process, carried out by molecular determinants deposited in the oocyte during oogenesis. On the other hand, segmentation is of zygotic nature, being the consequence of the synthesis of various components by the growing embryo. The enhancement in total B. microplus RNA was observed after cellularization, corroborating the replacement of maternal-driven processes by embryonic zygotic expression. An abrupt increase in oxygen consumption was observed from cellularization until the 8th day of development. The reduction in dry weight at the same period and the susceptibility of oxygen consumption to KCN suggest that the respiration process is activated during early embryonic development. A marked decrease in total lipid content occurred between the 5th and 7th days of development, suggesting this is the main energy source for cellularization. A major reduction in carbohydrate content occurred later, between the 7th and 9th days, and it could be assigned to the morphological segmentation of the embryo. Although the total amount of proteins remains unchanged from oviposition to hatching, a 15% reduction in vitellin (VT) content was observed before cellularization, up to the 4th day after egglaying. This observation was correlated to the synthesis of new proteins needed to support early embryo development. Additional 20% of VT was consumed thereafter, mainly at the end of embryogenesis, and in this case VT is probably used as energy source to the older embryo. Altogether, these data indicate different energy sources for maternal and zygotic driven processes.
本研究评估了微小牛蜱在整个胚胎发育阶段主要潜在能量来源的利用动力学。这种节肢动物的胚胎发育在21天内完成。胚盘的细胞化在第6天发生，随后迅速进行胚带延伸和分节，其最初迹象在第7天可见。细胞化通常是一个由母体驱动的过程，由卵子发生过程中沉积在卵母细胞中的分子决定因素执行。另一方面，分节具有合子性质，是发育中的胚胎合成各种成分的结果。细胞化后观察到微小牛蜱总RNA增加，证实了母体驱动过程被胚胎合子表达所取代。从细胞化到发育的第8天观察到耗氧量突然增加。同期干重的减少以及耗氧量对KCN的敏感性表明呼吸过程在胚胎早期发育期间被激活。在发育的第5天至第7天之间，总脂质含量显著下降，表明这是细胞化的主要能量来源。碳水化合物含量在稍后的第7天至第9天之间大幅减少，这可能与胚胎的形态分节有关。尽管从产卵到孵化蛋白质总量保持不变，但在细胞化之前，即产卵后第4天之前，观察到卵黄蛋白（VT）含量减少了15%。这一观察结果与支持早期胚胎发育所需新蛋白质的合成相关。此后又消耗了另外20%的VT，主要在胚胎发育末期，在这种情况下，VT可能被用作较老胚胎的能量来源。总之，这些数据表明母体驱动过程和合子驱动过程的能量来源不同。
