scholarly journals Gastrodermis ultrastructure of the different life stages of the polyopisthocotylean monogenean gill parasite Discocotyle sagittata

2021 ◽  
Author(s):  
Joanne Cable ◽  
Mohamed Mohamed El-Naggar
Keyword(s):  
Salmo Trutta ◽  
Structural Organization ◽  
Alimentary Tract ◽  
Blood Feeding ◽  
Life Stages ◽  
Variable Size ◽  
Digestive Cells ◽  
Gill Parasite ◽  
Apical Cytoplasm ◽  
Gill Lamellae

AbstractThe polyopisthocotylean Discocotyle sagittata is a blood-feeding monogenean that infects the gill lamellae of rainbow trout, Oncorhynchus mykiss, and brown trout, Salmo trutta. The ultrastructure of their alimentary tract, at different stages of the life cycle, was previously unknown. Here, we show that the gastrodermis of the oncomiracidium, subadult, and adult D. sagittata follows the same structural organization as that of other blood-feeding polyopisthocotyleans, being composed of digestive cells alternating with a connecting syncytium. Digestive cells of the oncomiracidium are found in three developmental forms: undifferentiated, developing differentiated, and differentiated (presumably functioning) cells whereas those of adult and subadult are present in a single functioning state with variable size and content. The apical cytoplasm of adult digestive cells forms conical outgrowths, a feature which is absent in the oncomiracidium. The connecting syncytium of the oncomiracidium has no evidence of metabolic activity, while that of adult and subadult is metabolically active. The lamellae of the connecting syncytium of adults and subadults are more numerous and larger, and their terminal portions are expanded, compared with those of the oncomiracidium. Parallel, tubular, membranous structures are characteristic of the apical cytoplasm of the connecting syncytium of the oncomiracidium. Luminal lamella in the oncomiracidium, subadult, and adult form balloon-like structures enclosing some luminal contents, but those of the oncomiracidium are larger, bounded by nucleated cytoplasmic layer, and enclose more luminal contents. The possible functions of these structures and mechanism of digestion in both oncomiracidium and adult are discussed.

scholarly journals Strong Effects of Temperature on the Early Life Stages of a Cold Stenothermal Fish Species, Brown Trout (Salmo trutta L.)

PLoS ONE ◽  
2016 ◽  
Vol 11 (5) ◽  
pp. e0155487 ◽  
Author(s):  
Emilie Réalis-Doyelle ◽  
Alain Pasquet ◽  
Daniel De Charleroy ◽  
Pascal Fontaine ◽  
Fabrice Teletchea
Keyword(s):  
Brown Trout ◽  
Fish Species ◽  
Early Life ◽  
Salmo Trutta ◽  
Life Stages ◽  
Early Life Stages ◽  
Brown Trout Salmo Trutta ◽  
Effects Of Temperature

An unusual structural organization to the gut of a digenetic trematode, Fellodistomum fellis

Parasitology ◽  
1982 ◽  
Vol 85 (1) ◽  
pp. 53-60 ◽  
Author(s):  
D. W. Halton
Keyword(s):  
Cell Surface ◽  
Elemental Analysis ◽  
Structural Organization ◽  
Digenetic Trematode ◽  
Blood Components ◽  
Ultrastructural Examination ◽  
Anterior Portion ◽  
Digestive Cells ◽  
Histochemical Tests ◽  
Host Blood

SUMMARYAn ultrastructural examination of Fellodistomum fellis has revealed that the caecal lining consists of 2 distinct components: (a) cup-shaped digestive cells and (b) a pleomorphic layer of cytoplasm which supports and separates individual digestive cells. The digestive cells sequester host blood components within apical pockets formed by lamellated extensions of the cell surface, and undergo asynchronous, cyclical transformations in morphology associated with extracellular digestion and with the extrusion to the gut lumen of pigmented digestive residues. Histochemical tests and elemental analysis of the pigment suggest that it is a ferripor-phyrin, haematin. In the anterior portion of the caecum the supporting cytoplasmic layer is in continuity with the oesophageal tegument and snares the same ultrastructure. It is concluded that the digestive cells are supported by an extension of the foregut tegument.

scholarly journals Interacting Effects of Polystyrene Microplastics and the Antidepressant Amitriptyline on Early Life Stages of Brown Trout (Salmo trutta f. fario)

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2361 ◽  
Author(s):  
Hannah Schmieg ◽  
Janne K.Y. Burmester ◽  
Stefanie Krais ◽  
Aki S. Ruhl ◽  
Selina Tisler ◽  
...  
Keyword(s):  
Brown Trout ◽  
Early Life ◽  
Salmo Trutta ◽  
Aquatic Organisms ◽  
Acetylcholinesterase Activity ◽  
Tricyclic Antidepressant ◽  
Life Stages ◽  
Early Life Stages ◽  
Scientific Discussion ◽  
Resting Behavior

Whether microplastics themselves or their interactions with chemicals influence the health and development of aquatic organisms has become a matter of scientific discussion. In aquatic environments, several groups of chemicals are abundant in parallel to microplastics. The tricyclic antidepressant amitriptyline is frequently prescribed, and residues of it are regularly found in surface waters. In the present study, the influence of irregularly shaped polystyrene microplastics (<50 µm), amitriptyline, and their mixture on early life-stages of brown trout were investigated. In a first experiment, the impacts of 100, 104, and 105 particles/L were studied from the fertilization of eggs until one month after yolk-sac consumption. In a second experiment, eggs were exposed in eyed ova stages to 105, 106 particles/L, to amitriptyline (pulse-spiked, average 48 ± 33 µg/L) or to two mixtures for two months. Microplastics alone did neither influence the development of fish nor the oxidative stress level or the acetylcholinesterase activity. Solely, a slight effect on the resting behavior of fry exposed to 106 particles/L was observed. Amitriptyline exposure exerted a significant effect on development, caused elevated acetylcholinesterase activity and inhibition of two carboxylesterases. Most obvious was the severely altered swimming and resting behavior. However, effects of amitriptyline were not modulated by microplastics.

scholarly journals THE FINE STRUCTURE OF THE PIGMENT EPITHELIUM IN THE ALBINO RAT

1962 ◽  
Vol 14 (3) ◽  
pp. 459-474 ◽  
Author(s):  
John E. Dowling ◽  
I. R. Gibbons
Keyword(s):  
Inclusion Bodies ◽  
Pigment Epithelium ◽  
Rod Outer Segments ◽  
Variable Size ◽  
Albino Rat ◽  
Pigment Epithelial ◽  
Hepatic Cells ◽  
Apical Cytoplasm ◽  
Granular Matrix ◽  
The Relationship

In this report, particular attention is paid to the inclusion bodies found in the apical cytoplasm of the pigment epithelial cell. These bodies are of variable size and form. The smallest (0.4 µ diameter) consist of a granular matrix enclosed by a single membrane, and are similar to the lysosomes of hepatic cells. Larger inclusion bodies contain areas of lamellated material in addition to granular matrix. The largest particles seen (2 µ diameter) are almost entirely lamellar. These different forms seem closely related, for it is possible to find all transitional stages between the smallest and largest particles. The relationship between the lamellar inclusion bodies and the rod outer segments is discussed.

scholarly journals Ultrastructural observations on the oncomiracidium epidermis and adult tegument of Discocotyle sagittata, a monogenean gill parasite of salmonids

2021 ◽  
Vol 120 (3) ◽  
pp. 899-910
Author(s):  
Mohamed Mohamed El-Naggar ◽  
Richard C Tinsley ◽  
Jo Cable
Keyword(s):  
Surface Layer ◽  
Cell Layer ◽  
Ciliated Cell ◽  
The Body ◽  
Life Stages ◽  
Sensory Receptors ◽  
Ciliated Cells ◽  
Membrane Turnover ◽  
Free Swimming ◽  
Gill Parasite

AbstractDuring their different life stages, parasites undergo remarkable morphological, physiological, and behavioral “metamorphoses” to meet the needs of their changing habitats. This is even true for ectoparasites, such as the monogeneans, which typically have a free-swimming larval stage (oncomiracidium) that seeks out and attaches to the external surfaces of fish where they mature. Before any obvious changes occur, there are ultrastructural differences in the oncomiracidium’s outer surface that prepare it for a parasitic existence. The present findings suggest a distinct variation in timing of the switch from oncomiracidia epidermis to the syncytial structure of the adult tegument and so, to date, there are three such categories within the Monogenea: (1) Nuclei of both ciliated cells and interciliary cytoplasm are shed from the surface layer and the epidermis becomes a syncytial layer during the later stages of embryogenesis; (2) nuclei of both ciliated cells and interciliary syncytium remain distinct and the switch occurs later after the oncomiracidia hatch (as in the present study); and (3) the nuclei remain distinct in the ciliated epidermis but those of the interciliary epidermis are lost during embryonic development. Here we describe how the epidermis of the oncomiracidium of Discocotyle sagittata is differentiated into two regions, a ciliated cell layer and an interciliary, syncytial cytoplasm, both of which are nucleated. The interciliary syncytium extends in-between and underneath the ciliated cells and sometimes covers part of their apical surfaces, possibly the start of their shedding process. The presence of membranous whorls and pyknotic nuclei over the surface are indicative of membrane turnover suggesting that the switch in epidermis morphology is already initiated at this stage. The body tegument and associated putative sensory receptors of subadult and adult D. sagittata are similar to those in other monogeneans.

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