The neuro-muscular system in cercaria with different patterns of locomotion

Abstract

The neuro-muscular system (NMS) of cercariae with different swimming patterns was studied with immunocytochemical methods and confocal scanning laser microscopy. Specimens of the continuously swimming Cercaria parvicaudata, Maritrema subdolum and Himasthla elongata were compared with specimens of the intermittently swimming Cryptocotyle lingua and the attached Podocotyle atomon. The patterns of F-actin in the musculature, 5-HT immunoreactive (-IR), FMRFamide-IR neuronal elements, α-tubulin-IR elements in the nervous and sensory systems and DAPI-stained nuclei were investigated. The general plan of the NMS was similar in all cercariae studied. No major structural differences in the patterns of muscle fibres were observed. However, in the tail of C. lingua, transverse muscle fibres connecting the bands of longitudinal muscles were found. No major structural differences in the 5-HT- or FMRFamide-IR nervous systems were observed. The number of 5-HT-IR neurones in the cercarial bodies varied between 12 and 14. The number and distribution of the α-tubulin-IR processes on the cercarial bodies and tails differed from each other. The relation between the number and structure of the α-tubulin-IR processes and the host finding strategy of the cercariae is discussed. A detailed schematic picture of the NMS in the tails of C. lingua and M. subdolum is presented.

The neuromuscular system in freshwater furcocercaria from Belarus. II Diplostomidae, Strigeidae, and Cyathocotylidae

“…As expected, the 5-HT-IR fibers and neurons in all the investigated species form orthogonal patterns that are similar to those that have been reported from cercariae of other species (see Terenina et al 2006;Tolstenkov et al 2010Tolstenkov et al , 2011a. The number of paired 5-HT-IR neurons in the bodies of the investigated cercariae varied between five and eight, and between six and eight in the literature mentioned above.…”

“…The checked pattern formed by the transverse muscle fibers in the tails stem of D. pseudospathaceum, C. szidati, A. burti, H. volgensis, and P. ovatus has not been observed in B. polonica, T. szidati, and T. franki (Tolstenkov et al 2011b) nor in any other cercariae studied (Tolstenkov et al 2011a;Halton and Maule 2004). Max projection of the FMRFamide-IR nervous system in the body of Holostephanus volgensis.…”

“…The organization of the neuromuscular system (NMS) and the distribution of neurotransmitters have been studied in several species of cercariae (see Tolstenkov et al 2011a). However, comparatively little is known about the NMS in many taxons of furcocercariae.…”

Spontaneous Electrical Activity and Spikes in the Tail of Marine Cercariae

“…Swimming cercariae show distinctive behavioural patterns related to their strategy of host finding and infection and can be divided into two groups: cercariae with a continuous swimming pattern and cercariae with an intermittent type of swimming pattern, where active phases alternate with passive phases when the cercariae soar in the water [ 1 ]. The difference in the swimming patterns correlates with the details of morphology in the tail—the larval locomotory organ, which is shown for two species chosen for the present research [ 3 ].…”

“…For the first time, APs have been detected in cercariae. The nervous system in the tail of C. lingua (tail size 270–420 × 33–40 μ m) contains a small number of paired symmetrical neurons [ 3 ]. In the region of spike recording, several pairs of candidate cells were observed with one pair of nuclei lying very close to the electrode ( Figure 2(a) ).…”