Kinetics of energy source utilization in Boophilus microplus (Canestrini, 1887) (Acari: Ixodidae) embryonic development.
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.
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.
Eldo
E
Campos
Jorge
J
Moraes
Arnoldo R
AR
Façanha
Erica
E
Moreira
Denise
D
Valle
Leonardo
L
Abreu
Pedro P A
PP
Manso
Aline
A
Nascimento
Marcelo
M
Pelajo-Machado
Henrique
H
Lenzi
Aoi
A
Masuda
Itabajara da Silva
Ida S
Vaz
Carlos
C
Logullo
D000818:Animals; D001835:Body Weight; D002241:Carbohydrates / Q000032:analysis; D004625:Embryo, Nonmammalian / Q000196:embryology / Q000378:metabolism / Q000648:ultrastructure; D004734:Energy Metabolism / Q000502:physiology*; D026863:Ixodidae / Q000196:embryology* / Q000378:metabolism* / Q000648:ultrastructure; D008055:Lipids / Q000032:analysis; D010058:Oviposition; D010101:Oxygen Consumption / Q000502:physiology; D011506:Proteins / Q000032:analysis; D012313:RNA / Q000032:analysis; D013997:Time Factors; D047048:Vitellins / Q000032:analysis; D014867:Water / Q000032:analysis
D002241:Carbohydrates; D008055:Lipids; D011506:Proteins; D047048:Vitellins; D014867:Water; D012313:RNA