Immunohistochemical analysis of nervous system regeneration in chimeric individuals of Dorvillea bermudensis (Polychaeta, Dorvilleidae)

Abstract

In regeneration experiments, 0.5% of the two- or five-segmented fragments of the polychaete Dorvillea bermudensis were found unexpectedly transplanted: two fragments of each that were lying close together during the initial period, fused and regenerated a chimeric individual. Of the three theoretical possibilities (i.e. fusion of (i). two posterior ends; (ii). one anterior and one posterior end; (iii). or two anterior ends) only the last two were realized. The similarly oriented fragments regenerated a normal animal while anterior-anterior fused ones produced two heads or a double head. Whether the ventral cords of the fragments are located vis-à-vis or adjacent, influences the course of regeneration as well. Immunohistochemical methods (anti-acetylated alpha-tubulin) in conjunction with confocal laser scanning microscopy were used to investigate the wiring pattern of the nervous systems of the grafts. In all cases, at least two supraesophageal ganglia were formed and palps, antennae and nuchal organs were innervated by the correct nerves but, in special cases, were innervated vice versa from the other brain. From these results it can be concluded that fusion of a regenerating connective with another connective results in formation of a new brain, irrespective of whether it belongs to the same nerve cord or not.

Nerve development, growth and differentiation during regeneration inEnchytraeus fragmentosusandStylaria lacustris(Oligochaeta)

“…This innervation pattern, later also described for E. japonensis by Myohara (2004), seems to be unique for oligochaete annelids because it has never been observed with any immunohistochemical method in polychaetes (Müller & Berenzen 2002; Müller et al . 2003; Müller & Henning 2004; Müller 2004). Furthermore, this plexus of parallel fibers seems to be a unique pattern for neuronal regeneration, because it was neither found during neuronal development of E. crypticus (Hessling & Westheide 1999) nor E. japonensis (Myohara 2004).…”

Structure and anterior regeneration of musculature and nervous system inCirratuluscf.cirratus(Cirratulidae, Annelida)

“…In contrast, we do not have data illustrating the transition from the lateral loops to the dorsal root of the circumesophageal connective, but they are obviously linked. Although distinct roots of the circumesophageal connective appear during anterior regeneration in other annelids (M€ uller et al, 2003;M€ uller, 2004a, 2004bM€ uller and Henning, 2004;Lindsay et al, 2008), the tripartite loop-like structure observed in C. cf. cirratus has not been described in these other species.…”

Histamine and gamma-aminobutyric acid in the nervous system of Pygospio elegans (Annelida: Spionidae): structure and recovery during reparative regeneration

“…Since confocal microscopy came into zoological research, most studies use only a restricted number of antibodies against neuroactive substances and structural proteins. The majority of modern studies concerned with the annelid nervous system were made using antibodies against acetylated α-tubulin, serotonin, and FMRFamide (4)(5)(6)(7)(8)(9)(10)(11)(12)(13).…”