Development of the Leech Nervous System

Isolation, characterization, and expression ofLe-msx, a maternally expressed member of the msx gene family from the glossiphoniid leech,Helobdella

“…Embryos were isolated from the parent and fixed immediately or were maintained in buffered saline medium, before fixation, until the desired stage of development was reached. Embryos were staged according to Stent et al (1992).…”

A distinct patterning mechanism of O and P cell fates in the development of the rostral segments of the leechHelobdella robusta: implications for the evolutionary dissociation of developmental pathway and morphological outcome

“…The embryos were cultured at 23°C in a buffered saline medium supplemented with antibiotics (0.05 mg/ml tetracycline, 100 units/ml penicillin, 100 units/ml streptomycin). Staging and nomenclature of the leech embryo in this study follow that described by Stent et al (Stent et al, 1992).…”

Functions of the subesophageal ganglion in the medicinal leech revealed by ablation of neuromeres in embryos

“…The SupraEG, which arises from the anteriormost part of the embryo called the prostomium (Stent et al, 1992), contains a variety of peptidergic neurons (Crisp et al, 2002), and its function remains relatively unexplored. The SubEG arises embryonically from four ganglion-like clusters of neurons at the anterior of the ventral nerve cord (Stent et al, 1992), and in adults this embryonic origin is reflected in the four bilaterally symmetric neuromeres (Fig.·1A,B). In adults, the cells of the SubEG are tightly compacted and the neuromere boundaries are somewhat obscured, making well-defined ablations with clean boundaries difficult to produce.…”