Previous investigations have indicated that c-Jun N-terminal kinase (JNK) regulates the maturation and aging of oocytes produced by deuterostome animals. In order to assess the roles of this kinase in a protostome, oocytes of the marine nemertean worm Cerebratulus were stimulated to mature and subsequently aged before being probed with phospho-specific antibodies against active forms of JNK and maturation-promoting factor (MPF). Based on blots of maturing oocytes, a 40-kD putative JNK is normally activated during germinal vesicle breakdown (GVBD), which begins at 30 min post-stimulation with seawater, whereas treating immature oocytes with JNK inhibitors downregulates both the 40-kD JNK signal and GVBD, collectively suggesting a 40-kD JNK may facilitate oocyte maturation. Along with this JNK activity, mature oocytes also exhibit high levels of MPF at 2 h post-stimulation. However, by ~6–8 h post-GVBD, mature oocytes lose the 40-kD JNK signal, and at ~20–30 h of aging, an ~48-kD phospho-JNK band arises as oocytes deactivate MPF and begin to lyse during a necroptotic-like mode of death. Accordingly, JNK inhibitors reduce the aging-related 48-kD JNK phosphorylation while maintaining MPF activity and retarding oocyte degradation. Such findings suggest that a 48-kD JNK may help deactivate MPF and trigger death. Possible mechanisms by which JNK activation either together with, or independently of, protein neosynthesis might stimulate oocyte degradation are discussed.

The north-west Pacific nemertean Cephalothrix simula has been introduced to the Pacific coast of North America, to the Mediterranean Sea and to the Atlantic coast of the Iberian Peninsula. This paper describes the first records of Cephalothrix simula from northern Europe, revealing a broader range for this non-endemic palaeonemertean species. A tree-based species delimitation method (Poisson Tree Process) employing the mitochondrial cox1 gene fragment reveals that four of five Cephalothrix specimens collected from The Netherlands correspond to Cephalothrix simula and only one to the endemic Cephalothrix rufifrons. The Cephalothrix simula sequences from The Netherlands exhibit the highest similarity with sequences from the native area and those from the invaded area in southern Europe. Its co-occurrence with the native Cephalothrix rufifrons in the same habitat is reported. External characters potentially distinguishing live Cephalothrix simula from Cephalothrix rufifrons are given. This finding raises the number of recorded species in The Netherlands to 20.

Lineus mcintoshii is recorded for the first time in Indian waters. This nemertean was sighted associated with the seaweed Bryopsis plumosa on the Thiruvananthapuram coast of Kerala, India.