Oogenesis and egg development in triatomines: a biochemical approach

Abstract

In triatomines, as well as in other insects, accumulation of yolk is a process in which an extra-ovarian tissue, the fat body, produces yolk proteins that are packed in the egg. The main protein, synthesized by the fat body, which is accumulated inside the oocyte, is vitellogenin. This process is also known as vitellogenesis. There are growing evidences in triatomines that besides fat body the ovary also produces yolk proteins. The way these yolk proteins enter the oocyte will be discussed. Yolk is a complex material composed of proteins, lipids, carbohydrates and other minor components which are packed inside the oocyte in an organized manner. Fertilization triggers embryogenesis, a process where an embryo will develop. During embryogenesis the yolk will be used for the construction of a new individual, the first instar nymph. The challenge for the next decade is to understand how and where these egg proteins are used up together with their non-protein components, in pace with the genetic program of the embryo, which enables cell differentiation (early phase of embryogenesis) and embryo differentiation (late phase) inside the egg.

Looking for reference genes for real‐time quantitative PCR experiments in Rhodnius prolixus (Hemiptera: Reduviidae)

“…For similar reasons, the fourth day after feeding was chosen for checking gene stability in the ovary and fat body. On this day, these organs are metabolically active as described above, with lipids (Pontes et al ., 2008) and carbohydrates (Mariano et al ., 2009) accumulating in the fat body and production of oocytes by the ovaries (Atella et al ., 2005).…”

“…Here, the expression of seven candidate genes was determined in the anterior and posterior midgut, ovary, fat body and flight muscle in adult female insects on the fourth day after a bloodmeal. On this day, R. prolixus metabolism is highly activated, as blood digestion is occurring in the intestinal tract (Grillo et al ., 2007; Ursic‐Bedoya et al ., 2008), nutrients are being accumulated in the fat body (Pontes et al ., 2008; Mariano et al ., 2009) and oocytes are growing at high rates (Atella et al ., 2005; Santos et al ., 2008). After analysis by ge N orm P lus and N orm F inder software, heat shock protein 70 kDa ( RpHSP70 ) and elongation factor 1 ( RpEF‐1 ) were indicated as the best reference genes in this kind of experiment (data not shown).…”

“…As also happens with other haematophagous arthropods, the bloodmeal regulates the physiology of R. prolixus (Atella et al ., 2005; Orchard, 2006). As a result, measurement of the expression of a target gene in unfed and fed insects is a useful experiment to look for gene function and regulation.…”

Rhodnius prolixus: From classical physiology to modern developmental biology

“…For instance, recent reports show that glucose metabolism is essential for early embryonic development in Tribolium and that GSK3 controls mitochondrial function and glucose metabolism during oocyte maturation in Drosophila (Sieber et al, 2016). In Rhodnius, in view of the potential for biological control of Chagas disease spread, the metabolic pathways linking blood ingestion and the development of eggs and embryos have been widely investigated (references in (Atella et al, 2005).…”

On the physico-chemical and physiological requirements of hemozoin formation promoted by perimicrovillar membranes in Rhodnius prolixus midgut

“…Much of the knowledge about PMVM came from studies of the hemipteran hemimetabolous kissing bug Rhodnius prolixus, one of the vectors of Chagas' disease and which has been used as a model for biochemical and physiological studies since the seminal work of Wigglesworth (Wigglesworth, 1934;Atella et al, 2005). In this species, production and secretion of PMVM by midgut cells occurs in response to the blood meal (Lane and Harrison, 1979;Billingsley and Downe, 1983;Albuquerque-Cunha et al, 2004).…”