Publisher Correction: Fish telocytes and their relation to rodlet cells in ruby-red-fin shark (rainbow shark) Epalzeorhynchos frenatum (Teleostei: Cyprinidae)

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Fish telocytes and their relation to rodlet cells in ruby-red-fin shark (rainbow shark) Epalzeorhynchos frenatum (Teleostei: Cyprinidae)

Telocytes comprise the major constituents of the supportive interstitial framework within the various organs. They form a 3D network between different types of stromal and non-stromal cells, which makes them distinctively vital. We have previously explored the origin of the peculiar rodlet cells, especially on their differential stages in aquatic species. The current study aimed at highlighting the relation of telocytes with different rodlet stages. Samples of fish, olfactory organs, and gills were processed for semi thin sections, transmission electron microscopy, and immunohistochemistry. It was evident in the study that telocytes formed a 3D interstitial network, entrapping stem cells and differentiating rodlet cells, to establish direct contact with stem cells. Differentiated stem cells and rodlet progenitor cells, practically in the granular and transitional stages, also formed ultrastructure junctional modifications, by which nanostructures are formed to establish cell contact with telocytes. Telocytes in turn also connected with macrophage progenitor cells. Telocytes (TCs) expressed CD34, CD117, VEGF, and MMP-9. In conclusion, telocytes established direct contact with the stem and rodlet cells in various differential stages. Telocytes may vitally influence stem/progenitor cell differentiation, regulate rodlet cell function, and express MPP-9 that may regulate immune cells functions especially, including movement and migration ability.

Microanalysis of Fish Ovarian Follicular Atresia: A Possible Synergic Action of Somatic and Immune Cells

The present study describes in detail the morphological characteristics of the process of ovarian follicular atresia in Redbelly tilapia (Coptodon zillii) during the nonbreeding season using light and electron microscopy and immunohistochemistry. The follicular regression process was initiated with shrinkage and disintegration of the nuclear membrane of oocytes resulting in dispersing of chromatin within the ooplasm, followed by marked hyperplasia and hypertrophy of follicular and granulosa cells, which exhibited a strong phagocytic activity to engulf the liquefied yolk particles. Rodlet cells and granulocytes were recorded on the follicular wall and invaded the regressed follicles. Rodlet cells expressed a strong immunoreactivity to matrix metalloperoxidase (MMP-9) and α-smooth muscle actin, while neutrophils expressed a strong reactivity to Myeloperoxidase-3 (MPO). In the advanced stage of follicular atresia, the yolk was almost phagocytized and resorbed and the regressed follicle lost its integrity and appeared to be formed of a cellular mass of phagocytic cells. Transmission electron microscopy revealed the presence of neutrophils, eosinophils, and dendritic cells within the atretic follicle in between these phagocytic cells. Moreover, numerous lysosomes, granules, and phagosomes were observed within the cytoplasm of both phagocytic cells and granulocytes. Telocytes were also demonstrated within the highly thickened richly vascularized theca layer during the late stages of follicular atresia. Immunohistochemical staining for caspase-3 established the participation of apoptosis in the advanced stages of follicular regression. Immune cells, rodlet cells, and telocytes in combination with follicular cells play an essential role in follicular atresia. In conclusion, the present study provides a new evidence on the role of both somatic and immune cells in the phenomenon of ovarian follicular atresia in Redbelly tilapia (Coptodon zillii) during the nonbreeding season.

Morphological Alternations of Intraepithelial and Stromal Telocytes in Response to Salinity Challenges

Summary statementThe article represent an experimental study in which we investigated the effect of the ssalinty on the communicating cells (telocytes) and their target cells including chloride, stem, Rodlet cells, myoblastsAbstractTelocyte is a communicating cell established relations to various types of cells. Few experimental studies are performed on telocytes. The current study investigated responce of telocytes to salinity stress in relations to osmoregualtory, immune and stem cells. We exposed Common carp to salinity level 0.2, 6, 10, 14 ppt. Gill samples were fixed and processed for microscopic and TEM. Two types of telocytes were identified: intraepithelial and stromal telocytes. Intraepithelial telocytes comprised the cellular lining of the lymph spaces where they shed the secretory vesicles. Stromal telocytes shed their secretory vesicles in the secondary circulatory vessels. Telocyte enlarged and exhibited high secretory activities. They exert their effect either by direct contact or by paracrine mode. In sanity treated samples, chloride cells enlarged and the mitochondria became cigar-shaped. pavement cells enlarged and micro-ridges elongated. Stromal telocytes established contact with stem cell and skeletal myoblast. Macrophages and Rodlet cells increased in number. In conclusion, intraepithelial and stromal responded to salinity stress by activation of cellular signaling. They play a major role in osmoregulation, immunity, and regeneration.

Are rodlet cells reliable biomarkers in Fundulus heteroclitus (L.)?

Two populations of killifish, Fundulus heteroclitus (L.) were studied, one from a high environmentally impacted site (Saw Mill Creek) exposed to pollutants, heavy metals and infected with parasites, the other from a habitat that was far less affected (Lemon Creek), on Staten Island, New York. The rodlet cell counts in the gills of each population were compared and correlated with the number of gill parasites. A comparison of rodlet cell numbers was also made between mature males and females within each population. Although the parasite infestation was significantly higher in the Saw Mill Creek population, the rodlet cell counts did not differ between the two groups. There was no statistical correlation between the parasite number and number of rodlet cells or between standard length and rodlet cells in each population. Also, the number of rodlet cells did not differ between males and females in either group. Furthermore, EM observations showed no difference in the activity of these cells. Our findings suggest that in F. heteroclitus, rodlet cells are not dependable biomarkers for evaluating the fish's response to parasites and environmental stressors. In addition, the sexual status of the fish does not appear to affect the number of rodlet cells.