Sofia A. Denisova, Sergei V. Shchenkov, Vladimir V. Lebedenkov
{"title":"Microanatomy and ultrastructure of the nervous system of adult Renicola parvicaudatus (Digenea: Renicolidae)","authors":"Sofia A. Denisova, Sergei V. Shchenkov, Vladimir V. Lebedenkov","doi":"10.1002/jmor.21672","DOIUrl":null,"url":null,"abstract":"<p>The digenean complex life cycle includes various morphological forms with different locomotory and behavioral activities, and the functional specialization of their nervous system is of importance for the transmission of these parasites. Adult digeneans acquire many adaptive features associated with the final settlement in a vertebrate host. Our study describes the general morphology and ultrastructure of the nervous system of the adult renicolid digenean <i>Renicola parvicaudatus</i> parasitizing the renal tubules of herring gulls. Using immunocytochemical and electron microscopic methods, we identified the distinctive characteristics of ganglia and synapses in the studied species. A comparative analysis of the organization of the nervous system of adult individuals and their continuously-swimming stylet cercariae revealed a number of stage-related differences in the composition of ganglia, the distribution of serotonin- and FMRFamide-immunoreactive neurons, the cytomorphology of neuron somata and free sensory endings. Thus, in adults, the presence of FMRFamide-positive neuron somata, accessory muscle bundles in the ganglionic cortex, and eight types of neuronal vesicles was detected, but no glia-like elements were identified. Their neurons are characterized by a larger volume of cytoplasm and also show greater ultrastructural diversity. Although the sensory papillae of adults do not vary in their external morphology as much as those of larvae, their sensory bulbs are more diverse in cytomorphology. Following our previous data on the “support” cell processes related to various tissues of the larvae and considered as glia-like structures, we also briefly present the identified features of the parenchyma, attachment organs and excretory system of adult individuals. The excretory system of adult <i>R. parvicaudatus</i> is characterized by the presence of unique terminal cells with several flame tufts, which are not typical either for the larvae of this species or for other digeneans studied so far. We also used molecular phylogenetic analysis to clarify species identification.</p>","PeriodicalId":16528,"journal":{"name":"Journal of Morphology","volume":null,"pages":null},"PeriodicalIF":1.5000,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Morphology","FirstCategoryId":"3","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/jmor.21672","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ANATOMY & MORPHOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The digenean complex life cycle includes various morphological forms with different locomotory and behavioral activities, and the functional specialization of their nervous system is of importance for the transmission of these parasites. Adult digeneans acquire many adaptive features associated with the final settlement in a vertebrate host. Our study describes the general morphology and ultrastructure of the nervous system of the adult renicolid digenean Renicola parvicaudatus parasitizing the renal tubules of herring gulls. Using immunocytochemical and electron microscopic methods, we identified the distinctive characteristics of ganglia and synapses in the studied species. A comparative analysis of the organization of the nervous system of adult individuals and their continuously-swimming stylet cercariae revealed a number of stage-related differences in the composition of ganglia, the distribution of serotonin- and FMRFamide-immunoreactive neurons, the cytomorphology of neuron somata and free sensory endings. Thus, in adults, the presence of FMRFamide-positive neuron somata, accessory muscle bundles in the ganglionic cortex, and eight types of neuronal vesicles was detected, but no glia-like elements were identified. Their neurons are characterized by a larger volume of cytoplasm and also show greater ultrastructural diversity. Although the sensory papillae of adults do not vary in their external morphology as much as those of larvae, their sensory bulbs are more diverse in cytomorphology. Following our previous data on the “support” cell processes related to various tissues of the larvae and considered as glia-like structures, we also briefly present the identified features of the parenchyma, attachment organs and excretory system of adult individuals. The excretory system of adult R. parvicaudatus is characterized by the presence of unique terminal cells with several flame tufts, which are not typical either for the larvae of this species or for other digeneans studied so far. We also used molecular phylogenetic analysis to clarify species identification.
期刊介绍:
The Journal of Morphology welcomes articles of original research in cytology, protozoology, embryology, and general morphology. Articles generally should not exceed 35 printed pages. Preliminary notices or articles of a purely descriptive morphological or taxonomic nature are not included. No paper which has already been published will be accepted, nor will simultaneous publications elsewhere be allowed.
The Journal of Morphology publishes research in functional, comparative, evolutionary and developmental morphology from vertebrates and invertebrates. Human and veterinary anatomy or paleontology are considered when an explicit connection to neontological animal morphology is presented, and the paper contains relevant information for the community of animal morphologists. Based on our long tradition, we continue to seek publishing the best papers in animal morphology.