Limits...
Glycogen and glucose metabolism are essential for early embryonic development of the red flour beetle Tribolium castaneum.

Fraga A, Ribeiro L, Lobato M, Santos V, Silva JR, Gomes H, da Cunha Moraes JL, de Souza Menezes J, de Oliveira CJ, Campos E, da Fonseca RN - PLoS ONE (2013)

Bottom Line: In oviparous insects the egg becomes an isolated system after egg laying with all energy conversion taking place during embryogenesis.Expression analysis via in situ hybridization shows that both genes are expressed only in the embryonic tissue, suggesting that embryonic and extra-embryonic cells display different metabolic activities. dsRNA adult female injection (parental RNAi) of both genes lead a reduction in egg laying and to embryonic lethality.Morphological analysis via DAPI stainings indicates that early development is impaired in Tc-GSK-3 and Tc-HexA1 RNAi embryos.

View Article: PubMed Central - PubMed

Affiliation: Laboratório Integrado de Bioquímica Hatisaburo Masuda (LIBHM), Núcleo de Pesquisas Ecológicas e Sócioambientais de Macaé (NUPEM), Universidade Federal do Rio de Janeiro (UFRJCampus Macaé), Rio de Janeiro, Brazil.

ABSTRACT
Control of energy metabolism is an essential process for life. In insects, egg formation (oogenesis) and embryogenesis is dependent on stored molecules deposited by the mother or transcribed later by the zygote. In oviparous insects the egg becomes an isolated system after egg laying with all energy conversion taking place during embryogenesis. Previous studies in a few vector species showed a strong correlation of key morphogenetic events and changes in glucose metabolism. Here, we investigate glycogen and glucose metabolism in the red flour beetle Tribolium castaneum, an insect amenable to functional genomic studies. To examine the role of the key enzymes on glycogen and glucose regulation we cloned and analyzed the function of glycogen synthase kinase 3 (GSK-3) and hexokinase (HexA) genes during T. castaneum embryogenesis. Expression analysis via in situ hybridization shows that both genes are expressed only in the embryonic tissue, suggesting that embryonic and extra-embryonic cells display different metabolic activities. dsRNA adult female injection (parental RNAi) of both genes lead a reduction in egg laying and to embryonic lethality. Morphological analysis via DAPI stainings indicates that early development is impaired in Tc-GSK-3 and Tc-HexA1 RNAi embryos. Importantly, glycogen levels are upregulated after Tc-GSK-3 RNAi and glucose levels are upregulated after Tc-HexA1 RNAi, indicating that both genes control metabolism during embryogenesis and oogenesis, respectively. Altogether our results show that T. castaneum embryogenesis depends on the proper control of glucose and glycogen.

Show MeSH
Glycogen content decreases in two phases during T. castaneum embryogenesis.High glycogen content is detected at the first four hours of embryogenesis and decreases between 4 and 8 hours of embryonic development (dashed box). Glycogen level is maintained or slightly increased between 8–12, 12–16, 16–20 and 20–24 hours. During the next 24 hours glycogen content largely decreases (grey box) and remains low until 72 hours.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3672164&req=5

pone-0065125-g006: Glycogen content decreases in two phases during T. castaneum embryogenesis.High glycogen content is detected at the first four hours of embryogenesis and decreases between 4 and 8 hours of embryonic development (dashed box). Glycogen level is maintained or slightly increased between 8–12, 12–16, 16–20 and 20–24 hours. During the next 24 hours glycogen content largely decreases (grey box) and remains low until 72 hours.

Mentions: Changes in glucose levels (Figure 2), in Hex activity (Figure 4F) and Tc-HexA1 expression (Figure 4A–E) suggest a tight control of beetle embryonic metabolism. Particularly important is the possibility that glucose upregulation observed in the second embryonic phase, after 24 hours, could be generated by glycogen conversion into glucose. To investigate this hypothesis we measured glycogen content. High glycogen content was observed in the first four hours of embryogenesis (0–4 hours) when compared to later stages (Figure 6). During the next five time-points of four hours (4–8, 8–12, 12–16, 16–20 and 20–24 hours) there is no significant change on glycogen levels with the exception of a small increase between 20–24 hours. Later on, a huge decrease in glycogen level occurs between 24–48 hours, leading to a basal level, whichis maintained in the next day of development (48–72 hours). To sum up, glycogen is degraded in two phases throughout embryogenesis and it is important to investigate the mechanism responsible for this regulation.


Glycogen and glucose metabolism are essential for early embryonic development of the red flour beetle Tribolium castaneum.

Fraga A, Ribeiro L, Lobato M, Santos V, Silva JR, Gomes H, da Cunha Moraes JL, de Souza Menezes J, de Oliveira CJ, Campos E, da Fonseca RN - PLoS ONE (2013)

Glycogen content decreases in two phases during T. castaneum embryogenesis.High glycogen content is detected at the first four hours of embryogenesis and decreases between 4 and 8 hours of embryonic development (dashed box). Glycogen level is maintained or slightly increased between 8–12, 12–16, 16–20 and 20–24 hours. During the next 24 hours glycogen content largely decreases (grey box) and remains low until 72 hours.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3672164&req=5

pone-0065125-g006: Glycogen content decreases in two phases during T. castaneum embryogenesis.High glycogen content is detected at the first four hours of embryogenesis and decreases between 4 and 8 hours of embryonic development (dashed box). Glycogen level is maintained or slightly increased between 8–12, 12–16, 16–20 and 20–24 hours. During the next 24 hours glycogen content largely decreases (grey box) and remains low until 72 hours.
Mentions: Changes in glucose levels (Figure 2), in Hex activity (Figure 4F) and Tc-HexA1 expression (Figure 4A–E) suggest a tight control of beetle embryonic metabolism. Particularly important is the possibility that glucose upregulation observed in the second embryonic phase, after 24 hours, could be generated by glycogen conversion into glucose. To investigate this hypothesis we measured glycogen content. High glycogen content was observed in the first four hours of embryogenesis (0–4 hours) when compared to later stages (Figure 6). During the next five time-points of four hours (4–8, 8–12, 12–16, 16–20 and 20–24 hours) there is no significant change on glycogen levels with the exception of a small increase between 20–24 hours. Later on, a huge decrease in glycogen level occurs between 24–48 hours, leading to a basal level, whichis maintained in the next day of development (48–72 hours). To sum up, glycogen is degraded in two phases throughout embryogenesis and it is important to investigate the mechanism responsible for this regulation.

Bottom Line: In oviparous insects the egg becomes an isolated system after egg laying with all energy conversion taking place during embryogenesis.Expression analysis via in situ hybridization shows that both genes are expressed only in the embryonic tissue, suggesting that embryonic and extra-embryonic cells display different metabolic activities. dsRNA adult female injection (parental RNAi) of both genes lead a reduction in egg laying and to embryonic lethality.Morphological analysis via DAPI stainings indicates that early development is impaired in Tc-GSK-3 and Tc-HexA1 RNAi embryos.

View Article: PubMed Central - PubMed

Affiliation: Laboratório Integrado de Bioquímica Hatisaburo Masuda (LIBHM), Núcleo de Pesquisas Ecológicas e Sócioambientais de Macaé (NUPEM), Universidade Federal do Rio de Janeiro (UFRJCampus Macaé), Rio de Janeiro, Brazil.

ABSTRACT
Control of energy metabolism is an essential process for life. In insects, egg formation (oogenesis) and embryogenesis is dependent on stored molecules deposited by the mother or transcribed later by the zygote. In oviparous insects the egg becomes an isolated system after egg laying with all energy conversion taking place during embryogenesis. Previous studies in a few vector species showed a strong correlation of key morphogenetic events and changes in glucose metabolism. Here, we investigate glycogen and glucose metabolism in the red flour beetle Tribolium castaneum, an insect amenable to functional genomic studies. To examine the role of the key enzymes on glycogen and glucose regulation we cloned and analyzed the function of glycogen synthase kinase 3 (GSK-3) and hexokinase (HexA) genes during T. castaneum embryogenesis. Expression analysis via in situ hybridization shows that both genes are expressed only in the embryonic tissue, suggesting that embryonic and extra-embryonic cells display different metabolic activities. dsRNA adult female injection (parental RNAi) of both genes lead a reduction in egg laying and to embryonic lethality. Morphological analysis via DAPI stainings indicates that early development is impaired in Tc-GSK-3 and Tc-HexA1 RNAi embryos. Importantly, glycogen levels are upregulated after Tc-GSK-3 RNAi and glucose levels are upregulated after Tc-HexA1 RNAi, indicating that both genes control metabolism during embryogenesis and oogenesis, respectively. Altogether our results show that T. castaneum embryogenesis depends on the proper control of glucose and glycogen.

Show MeSH