Architecture of the nervous system in metacercariae of Diplostomum pseudospathaceum Niewiadomska, 1984 (Digenea)
- 5 Downloads
The development of metacercariae of Diplostomum pseudospathaceum Niewiadomska, 1984 is accompanied by profound morphological transformations often characterized as metamorphosis, which makes these metacercariae an interesting case for studying the morphogenesis of the digenean nervous system. Although the nervous system of D. pseudospathaceum is one of the most extensively studied among digeneans, there are still gaps in our knowledge regarding the distribution patterns of some neuroactive substances, most notably neuropeptides. The present study addresses these gaps by studying pre-infective metacercariae of D. pseudospathaceum using immunochemical staining and confocal microscopy to characterize the distribution patterns of serotonin (5-HT) and two major groups of flatworm neuropeptides, FMRFamide-related (FaRPs) and substance P-related (SP) peptides. The general morphology of the nervous system was examined with antibodies to alpha-tubulin. The nervous system of the metacercariae was shown to conform to the most common morphology of the nervous system in the hermaphroditic generation, with three pairs of posterior nerve cords and four pairs of anterior nerves. The patterns of FaRP- and 5-HT immunoreactivity (IR) were similar to those revealed in earlier studies by cholinesterase activity, which is in accordance with the known role of these neurotransmitters in controlling muscle activity in flatworms. The SP-IR nervous system was significantly different and consisted of mostly bipolar cells presumably acting as mechanoreceptors. The architecture of the nervous system in D. pseudospathaceum metacercariae is discussed in comparison to that in cercariae of D. pseudospathaceum and metacercariae of related digenean species.
KeywordsNervous system Metacercariae 5-HT Substance P FMRFamide Alpha-tubulin
Confocal microscopy was performed at the “Taxon” Research Resource Centre (Zoological Institute, Russian Academy of Sciences) (http://www.ckp-rf.ru/ckp/3038/?sphrase_id=8879024).
This work was supported by budget funding (projects АААА-А17-117030110029-3 and АААА-А17-117030310322-3) of the Russian Academy of Sciences and by the Russian Foundation for Basic Research (grant 16-04-00593).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Bettendorf H (1897) Ueber Musculatur und Sinneszellen der Trematoden. Zool Jahrb Abt Anat Ontog Tiere 10:307–358Google Scholar
- Biserova NM (2015) Chapter 11. Platyhelminthes: Neodermata. In: structure and evolution of invertebrate nervous systems. Oxford University Press, Oxford, New YorkGoogle Scholar
- Bullock TH, Horridge GA (1965) Structure and function in the nervous system of invertebrates, vol 2. W.H. Freeman and Company, San-Francisco, LondonGoogle Scholar
- Czubaj A, Niewiadomska K (1991) Sensory endings in the daughter sporocyst of Diplostomum pseudospathaceum Niewiadomska, 1984 (Digenea, Diplostomidae). Acta Parasitologica Polonica 3:115–120Google Scholar
- Ginetsinskaya T (1988) Trematodes, their life cycles, biology and evolution. Amerind, New DelhiGoogle Scholar
- Gustafsson MKS (1988) Helminth nervous system. In: Parasitology in focus. Facts and trends. Springer, Berlin, Heidelberg, New York, pp 295–310Google Scholar
- Havet J (1900) Contribution à l'étude du système nerveux des trématodes (Distomum hepaticum). La Cellule 17:353–381Google Scholar
- Komiya Y (1938) Die Entwicklung des Exkretionssystems einiger Trematodenlarven aus Alster und Elbe, nebst Bemerkungen über ihren Entwicklungszyklus. Parasitol Res 10:340–385Google Scholar
- Niewiadomska K (1996) The genus Diplostomum - taxonomy, morphology and biology. Acta Parasitol 41:55–66Google Scholar
- Niewiadomska K, Czubaj A (1996) Sensory endings in Diplostomum pseudospathaceum Niewiadomska, 1984 cercariae (Digenea, Diplostomidae). Acta Parasitol 41:20–25Google Scholar
- Niewiadomska K, Czubaj A (2000) Ultrastructure of the excretory system in the metacercaria of Diplostomum pseudospathaceum Niew., 1984 (Digenea). Acta Parasitol 45:307–321Google Scholar
- Niewiadomska K, Maślińska D, Czubaj A, Pomorski P (1993) Distribution of serotonin immunoreactive (5HT-IR) neurons and fibers in metacercaria of Diplostomum paracaudum (Iles, 1959) (Digenea). Acta Parasitol 38:52–54Google Scholar
- Petrov A, Podvyaznaya I (2016b) Сhanges in spination patterns over the course of metacercarial development of Diplostomum pseudospathaceum Niewiadomska, 1984 (Trematoda, Diplostomidae). Parazitologiya 50:331–339Google Scholar
- Podvyaznaya IM (1999) The fine structure of the tegument of cercariae and developing metacercariae of Diplostomum chromatophorum (Trematoda: Diplostomidae). Parazitologiya 33:507–519Google Scholar
- Podvyaznaya IM (2013) Ultrastructural changes in the digestive system during the metacercarial development in Diplostomum pseudospathaceum (Trematoda: Digenea: Diplostomidae). Proc Zool Instit 317:101–109Google Scholar
- Shigin AA (1986) Trematodes of the fauna of USSR. The genus Diplostomum. Metacercariae. Nauka, Moscow (In Russian)Google Scholar
- Terenina NB, Gustafsson MKS (2014) The functional morphology of the nervouos system of parasitic flatworms (trematodes, cestodes). KMK scientific press, Moscow (In Russian)Google Scholar