Dynamics of vitellogenin synthesis in juvenile giant freshwater prawn Macrobrachium rosenbergii

Feb 21, 2006Journal of experimental zoology. Part A, Comparative experimental biology

Changes in egg yolk protein production in young giant freshwater prawns

AI simplified

Circadian Biology on OpenScience ↗PubMed ↗DOI ↗

Abstract

Hemolymph vitellogenin (Vg) levels in female juvenile Macrobrachium rosenbergii ranged from 0.04 to 2.2 mg/ml.

Eyestalk ablation induced rapid gonad development and increased Vg synthesis in female juveniles.
Vg mRNA expression in the hepatopancreas increased gradually in correlation with gonadosomatic index (GSI).
Vitellin accumulation in oocytes was linked to increased Vg mRNA synthesis, though expression was negligible in the ovary.
Juvenile Vg was composed of 199 and 90 kDa subunits, while the 102 kDa subunit found in adults was absent in juveniles.
Non-ablated juveniles did not show detectable levels of Vg, indicating a reliance on eyestalk factors for vitellogenesis.

AI simplified

The dynamics of vitellogenin (Vg) mRNA expression and patterns of Vg and vitellin distribution in the hepatopancreas and ovary of juvenile Macrobrachium rosenbergii were examined using real-time RT-PCR and immunohistochemical methods. Eyestalk ablation was seen to induce rapid development of the gonads and Vg synthesis in females. In the female hepatopancreas, Vg mRNA expression was observed several days following ablation, after which levels increased gradually with increasing gonadosomatic index (GSI). Vitellin accumulation in the oocytes also increased with increasing Vg mRNA synthesis; expression was however negligible in the ovary. Hemolymph Vg levels in females ranged from 0.04 to 2.2 mg/ml. SDS PAGE/Western blotting analysis of hemolymph samples revealed that juvenile Vg was composed of 199 and 90 kDa subunits; the 102 kDa subunit present in adult female Vg (Okuno et al., 2002. J Exp Zool 292:417-429) could not be detected at any stage of vitellogenesis in juveniles. Vg was not detectable in non-ablated juveniles. The results of this study confirmed that the mode of involvement of eyestalk factors in regulating vitellogenesis is intrinsic to both juveniles and adults, and that a basic pattern of Vg synthesis and processing is conserved. However, the fact that juveniles are not able to produce the same Vg levels observed in adult females, and do not reach high GSI levels culminating in spawning suggests that other factors and physiological conditions specific to adult females are necessary to demonstrate full reproductive ability.

Full Text

Full text is available at the source.

View full text ↗

Dynamics of vitellogenin synthesis in juvenile giant freshwater prawn Macrobrachium rosenbergii

Abstract

Full Text

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief

Abstract

Full Text

Related papers

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief