Molt-Inhibiting Hormone mRNA Levels and Ecdysteroid Titer during a Molt Cycle of the Blue Crab,Callinectes sapidus

Lee, Kara J.; Watson, R. Douglas; Roer, Robert D.

doi:10.1006/bbrc.1998.9215

Cited by 71 publications

(41 citation statements)

References 20 publications

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“…However, correlations were not observed in premoult animals, whichever normalization was used. Despite these caveats, our results contrast vividly with those obtained for C. sapidus where Northern blot analysis (using a lobster b-actin probe to normalize the data) indicated that MIH mRNA was dramatically (five-to 10-fold) downregulated during premoult [7]. However, in the penaeid shrimp, P. japonicus, MIH (SGP-IV) mRNA levels are not downregulated at this time [6].…”

Section: Discussioncontrasting

confidence: 99%

“…However, this simplistic hypothesis remains untested, and it seems likely that both changes in target organ sensitivity and synthesis/release patterns of neuropeptides may be relevant. Evidence that MIH synthesis may be dramatically reduced during late premoult has been suggested from qualitative measurement of MIH transcript abundance in premoult Callinectes sapidus eyestalks [7], and a reduction in sinus gland MIH content during late premoult has been observed in Procambarus clarkii [8]. However, an alternative explanation might be that the YO becomes refractive to MIH during premoult, as has been suggested for Penaeus vannamei [9].…”

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confidence: 95%

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Moult cycle‐related changes in biological activity of moult‐inhibiting hormone (MIH) and crustacean hyperglycaemic hormone (CHH) in the crab, Carcinus maenas

Chung

Webster

2003

European Journal of Biochemistry

133

102

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The currently accepted model of moult control in crustaceans relies entirely on the hypothesis that moult-inhibiting hormone (MIH) and crustacean hyperglycaemic hormone (CHH) repress ecdysteroid synthesis of the target tissue (Y-organ) only during intermoult, and that changes in synthesis and/or release of these neurohormones are central to moult control. To further refine this model, we investigated the biological activities of these neuropeptides in the crab Carcinus maenas, at the target tissue, receptor and cellular level by bioassay (inhibition of ecdysteroid synthesis), radioligand (receptor) binding assays, and second messenger (cGMP) assays, at defined stages of the moult cycle. To investigate possible moult cycle-related changes in neuropeptide biosynthesis, steady-state transcript levels of both neuropeptide mRNAs were measured by quantitative RT-PCR, and stored neuropeptide levels in the sinus gland were quantified during intermoult and premoult. The results show that the most important level of moult control lies within the signalling machinery of the target tissue, that expression and biosynthesis of both neuropeptides is constant during the moult cycle, and are not central to the currently accepted model of moult control.

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Section: Discussioncontrasting

confidence: 99%

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confidence: 95%

Moult cycle‐related changes in biological activity of moult‐inhibiting hormone (MIH) and crustacean hyperglycaemic hormone (CHH) in the crab, Carcinus maenas

Chung

Webster

2003

European Journal of Biochemistry

133

102

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“…More recently, Chung et al (1997) have shown the presence of mRNA for ecdysteroid receptors in eyestalks of U. pugilator, thus demonstrating the indispensable molecular basis for a putative involvement of the neuroendocrine center. In addition, MIH mRNA levels were demonstrated to undergo stage-specific changes in the eyestalk of Callinectes sapidus, which negatively correlate with the 20E titer in the haemolymph (Lee et al, 1998). However, the fact that eyestalkless animals show similar 20E titer curves as natural premolt animals suggests that 20E-inhibited MIH release is not the only trigger for the steep increase in D 2 /D 3 .…”

Section: Discussionmentioning

confidence: 98%

Ecdysteroid biosynthesis in crayfish Y-organs: Feedback regulation by circulating ecdysteroids

Dell

Sedlmeier

Böcking

et al. 1999

Arch. Insect Biochem. Physiol.

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“…Our particular interest is the role of GCs in MIH and CHH signaling in the crustacean YO; both neuropeptides inhibit molting by suppressing YO ecdysteroidogenesis (Chung and Webster, 2003;Webster and Keller, 1986). Thus, entry into premolt is correlated with reduced MIH synthesis in the eyestalk and a corresponding increase in hemolymph ecdysteroid (Chen et al, 2007;Lee et al, 1998). Various environmental stressors inhibit molting, which may be mediated by elevated CHH in the hemolymph (Chang et al, 1998;Chung and Webster, 2003;Chung and Webster, 2005).…”

Section: Discussionmentioning

confidence: 99%

Effects of elevated ecdysteroid on tissue expression of three guanylyl cyclases in the tropical land crab Gecarcinus lateralis: possible roles of neuropeptide signaling in the molting gland

Lee

Bader

Chang

et al. 2007

Journal of Experimental Biology

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SUMMARY Two eyestalk (ES) neuropeptides, molt-inhibiting hormone (MIH) and crustacean hyperglycemic hormone (CHH), increase intracellular cGMP levels in target tissues. Both MIH and CHH inhibit ecdysteroid secretion by the molting gland or Y-organ (YO), but apparently through different guanylyl cyclase(GC)-dependent pathways. MIH signaling may be mediated by nitric oxide synthase (NOS) and NO-sensitive GC. CHH binds to a membrane receptor GC. As molting affects neuropeptide signaling, the effects of ecdysteroid on the expression of the land crab Gecarcinus lateralis β subunit of a NO-sensitive GC (Gl-GC-Iβ), a membrane receptor GC (Gl-GC-II) and a NO-insensitive soluble GC (Gl-GC-III) were determined. Gl-GC-Iβ isoforms differing in the absence or presence of an N-terminal 32-amino acid sequence and Gl-GC-III were expressed at higher mRNA levels in ES ganglia, gill,hepatopancreas, ovary and testis, and at lower levels in YO, heart and skeletal muscle. Three Gl-GC-II isoforms, which vary in the length of insertions (+18, +9 and +0 amino acids) within the N-terminal ligand-binding domain, differed in tissue distribution. Gl-GC-II(+18) was expressed highly in striated muscle (skeletal and cardiac muscles); Gl-GC-II(+9) was expressed in all tissues examined (ES ganglia, YO, gill, hepatopancreas, striated muscles and gonads); and Gl-GC-II(+0) was expressed in most tissues and was the dominant isoform in ES and thoracic ganglia. ES ablation, which increased hemolymph ecdysteroid, increased Gl-GC-II(+18) mRNA level in claw muscle. Using real-time RT-PCR, ES ablation increased Gl-GC-Iβ, Gl-GC-III and ecdysone receptor mRNA levels in the YOs ∼ten-, ∼four- and∼twofold, respectively, whereas Gl-GC-II mRNA level was unchanged. A single injection of 20-hydroxyecdysone into intact animals transiently lowered Gl-GC-Iβ in hepatopancreas, testis and skeletal muscle, and certain Gl-GC-II isoforms in some of the tissues. These data suggest that YO and other tissues can modulate responses to neuropeptides by altering GC expression.

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Molt-Inhibiting Hormone mRNA Levels and Ecdysteroid Titer during a Molt Cycle of the Blue Crab,Callinectes sapidus

Cited by 71 publications

References 20 publications

Moult cycle‐related changes in biological activity of moult‐inhibiting hormone (MIH) and crustacean hyperglycaemic hormone (CHH) in the crab, Carcinus maenas

Moult cycle‐related changes in biological activity of moult‐inhibiting hormone (MIH) and crustacean hyperglycaemic hormone (CHH) in the crab, Carcinus maenas

Ecdysteroid biosynthesis in crayfish Y-organs: Feedback regulation by circulating ecdysteroids

Effects of elevated ecdysteroid on tissue expression of three guanylyl cyclases in the tropical land crab Gecarcinus lateralis: possible roles of neuropeptide signaling in the molting gland

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