Differential expression of four genes encoding molluscan insulin-related peptides in the central nervous system of the pond snail Lymnaea stagnalis

1992 ◽  
Vol 269 (1) ◽  
pp. 183-188 ◽  
Author(s):  
I. Meester ◽  
M. D. Ramkema ◽  
J. van Minnen ◽  
H. H. Boer
1991 ◽  
Vol 279 (3) ◽  
pp. 837-842 ◽  
Author(s):  
P L Hordijk ◽  
H D F H Schallig ◽  
R H M Ebberink ◽  
M de Jong-Brink ◽  
J Joosse

In the pond snail Lymnaea stagnalis infected with the schistosome parasite Trichobilharzia ocellata, a peptide called schistosomin is released from the central nervous system, which counteracts the bioactivity of a number of gonadotropic hormones. This leads to inhibition of the reproductive activities of the infected snail. In order to determine the structure of schistosomin, the neuropeptide was purified from the central nervous system using gel-permeation chromatography and reverse-phase h.p.l.c. The complete primary structure of the peptide was determined by N-terminal sequencing and peptide mapping. Schistosomin is a single-chain molecule of 79 amino acids with a molecular mass of 8738 Da. The peptide contains eight cysteine residues which may give rise to four intramolecular disulphide bridges that fold the peptide into a stable globular structure. A database search did not reveal any known peptides that show significant sequence similarity to schistosomin. By means of immunocytochemistry, the peptide was shown to be localized in the growth-controlling neurosecretory light green cells, which are located in the cerebral ganglia of the central nervous system of Lymnaea. In addition to schistosomin, these neurons are known to produce various insulin-related peptides.


2019 ◽  
Author(s):  
Brittany A. Mersman ◽  
Sonia N. Jolly ◽  
Zhenguo Lin ◽  
Fenglian Xu

AbstractConnections between neurons called synapses are the key components underlying all nervous system functions of animals and humans. However, important genetic information on the formation and plasticity of one type, the electrical (gap junction-mediated) synapse, is severely understudied, especially in invertebrates. In the present study, we set forth to identify and characterize the gap junction-encoding gene innexin in the central nervous system (CNS) of the mollusc pond snail Lymnaea stagnalis (L. stagnalis). With PCR, 3’ and 5’ RACE, and BLAST searches, we identified eight innexin genes in the L. stagnalis nervous system named Lst Inx1-8. Phylogenetic analysis revealed that the L. stagnalis innexin genes originated from a single copy in the common ancestor of molluscan species by multiple gene duplication events and have been maintained in L. stagnalis since they were generated. The paralogous innexin genes demonstrate distinct expression patterns among tissues. In addition, one paralog, Lst Inx1, exhibits heterogeneity in cells and ganglia, suggesting the occurrence of functional diversification after gene duplication. These results introduce possibilities to study an intriguing potential relationship between innexin paralog expression and cell-specific functional outputs such as heterogenic ability to form channels and exhibit synapse plasticity. The L. stagnalis CNS contains large neurons and a functionally defined network for behaviors; with the introduction of L. stagnalis in the gap junction field, we are providing novel opportunities to combine genetic research with direct investigation of functional outcomes at the cellular, synaptic, and behavioral levels.Summary StatementBy characterizing the gap junction gene innexin in Lymnaea stagnalis, we open opportunities for novel studies on the regulation, plasticity, and evolutionary function of electrical synapses throughout the animal kingdom.


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