Hemocyte activation and nodule formation in the giant keyhole limpet, <scp><i>Megathura crenulata</i></scp>

Martin, Gary G.; Stamnes, Stephanie; Henderson, Nicola; Lum, Juliette; Rubin, Nicole; Williams, Jonathan P.

doi:10.1111/ivb.12355

Cited by 3 publications

(4 citation statements)

References 62 publications

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“…Overall, TEM observations revealed that histological morphology of melanosome or melanocyte in mantle of C. gigas was like that observed in foot epithelium of the ablone H. tuberculate (Bravo Portela et al, 2012) and skin epithelium of keyhole limpet Megathura crenulate (Martin et al, 2021). Additionally, another structure of melanin was observed in the epithelium of mantle in H. tuberculate that melanin was arranged as spiral membranes (Nogal & García, 2015).…”

Section: Discussionmentioning

confidence: 87%

“…In vertebrate, a large number of melanocytic markers have been investigated, among of these, TYR is a highly specific and sensitive marker for melanocytic differentiation (Ordóñez, 2014; Saliba & Bhawan, 2021). Nevertheless, to our knowledge, rare paper related to immunohistochemical makers of melanin in bivalve was published, because in previous studied cases, melanin granule was commonly identified using histochemistry staining (Bravo Portela et al, 2012; Han et al, 2022; Jiang et al, 2020; Martin et al, 2021; Nogal & García, 2015).…”

Section: Introductionmentioning

confidence: 99%

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Histological, elemental, and ultrastructural analysis of melanin in mantle of Pacific oyster (Crassostrea gigas)

et al. 2022

Microscopy Res & Technique

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Colorful shell of bivalve is mainly because of the biological pigments, of which melanin plays an important role in shell color formation. More and more studies focus on the genes function involved in melanin synthesis, but relatively few studies address the biochemical character and ultrastructure of melanin in bivalve from microscopic perspective. Here, we investigated the histological structure of mantle of Crassostrea gigas with orange shell color. Distribution of melanin in mantle was verified with histochemical staining. In addition, immunofluorescence technique showed that strongly positive signal of CgTYR was specific to the mantle margin, which is consistence with the location of brown granules in H&E staining. The further result of elementary composition of melanin displayed that metal Ca, Fe, and Zn were detected using scanning transmission electron microscope and energy dispersive spectroscopy mapping methods. Next, based on TEM observations, it was speculated that the series of cellular events leading to the formation and release of melanin. Melanocyte in the primary stage showed many mitochondria and rough endoplasmic reticulum as well as an extensive Golgi complex with numerous vesicles intermingled with melanosome.Subsequently, melanosome was expended and their hue gradually intensified, and Golgi complex and mitochondria were still observed in the cytoplasm. Finally, after melanosome was discharged into intercellular spaces, the disintegration of membranes in some cells, and severe cellular vacuolization. These data enrich the understanding of ultrastructural characteristic and formation of melanin in mantle of bivalve and pave the way for further investigating shell coloration at the cellular level.

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Section: Discussionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Histological, elemental, and ultrastructural analysis of melanin in mantle of Pacific oyster (Crassostrea gigas)

et al. 2022

Microscopy Res & Technique

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“…Pomacea canaliculata hemocytes, as those of some other gastropods ( 19 , 20 ), exhibit in vitro a notable tendency to approach toward one another, resulting in the formation of aggregates. This phenomenon appears to be a fundamental characteristic of hemocyte behavior in P. canaliculata , as evidenced by the formation of spheroidal hemocyte nodules in primary cultures ( 21 ).…”

Section: Discussionmentioning

confidence: 99%

Pathogenesis of an experimental mycobacteriosis in an apple snail

Cruz-Flores,

Rodriguez,

Giai

et al. 2023

Front. Immunol.

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In this work, we aimed at investigating cell and tissue responses of the apple snail Pomacea canaliculata, following the inoculation of the zoonotic pathogen Mycobacterium marinum. Different doses were tested (10, 20, 65, and 100 M CFU) and the mortality rate was negligible. The histopathogenesis was followed at 4, 9, and 28 days after inoculation. Overt histopathological lesions were consistently observed after the two largest doses only. In the lung, marked hemocyte aggregations, including intravascular nodule formation, were observed within the large blood veins that run along the floor and roof of this organ. Hemocyte aggregations were found occluding many of the radial sinuses supplying the respiratory lamina. Acid-fast bacilli were contained in the different hemocyte aggregations. In addition, hemocytes were observed infiltrating the storage tissue, which makes up most of the lung wall, and the connective tissue of the mantle edge. Additionally, signs of degradation in the storage tissue were observed in the lung wall on day 28. In the kidney, nodules were formed associated with the constitutive hemocyte islets and with the subpallial hemocoelic space, in whose hemocytes the acid-fast structures were found. Electron microscopy analysis revealed the presence of bacteria-containing phagosomes within hemocytes located in the surface zone of the islets. Additionally, electron-dense spheroidal structures, which are likely remnants of digested mycobacteria, were observed in close proximity to the hemocytes’ nuclei. The size attained by the hemocyte nodules varied during the observation period, but there was no clear dependence on dose or time after inoculation. Nodules were also formed subpallially. Some of these nodules showed 2–3 layers with different cellular composition, suggesting they may also form through successive waves of circulating cells reaching them. Nodular cores, including those formed intravascularly in the lung, would exhibit signs of hemocyte dedifferentiation, possibly proliferation, and death. Hemocyte congestion was observed in the hemocoelic spaces surrounding the pallial ends of the renal crypts, and the renal crypts themselves showed de-epithelization, particularly on day 28. The diverse cellular responses of P. canaliculata to M. marinum inoculation and the high resilience of this snail to the pathogen make it a suitable species for studying mycobacterial infections and their effects on cellular and physiological processes.

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“…Nodular hemocyte formations are known to occur in the major clades of Protostomia (e.g., 66 – 69 ) and Deuterostomia (e.g., 70 ). A particular case among the latter are the nodules formed in the zebrafish larvae ( Danio rerio , Teleostei, Cyprinidae) in response to Mycobacterium marinum inoculation, because these nodules (usually called granulomas or tubercles in the context of tuberculosis studies) have received a particular attention as a model of mycobacterial pathogenesis ( 71 – 75 ).…”

Section: The Ampullariid Immune System From a Morpho-functional Persp...mentioning

confidence: 99%

A Dissenters’ View on AppleSnail Immunobiology

2022

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We stand as dissenters against the acceptance of scientific knowledge that has not been built on empirical data. With this in mind, this review synthesizes selected aspects of the immunobiology of gastropods and of apple snails (Ampullariidae) in particular, from morphological to molecular and “omics” studies. Our trip went through more than two centuries of history and was guided by an evo-devo hypothesis: that the gastropod immune system originally developed in the mesenchymal connective tissue of the reno-pericardial complex, and that in that tissue some cells differentiated into hematopoietically committed progenitor cells that integrate constitutive hemocyte aggregations in the reno-pericardial territory, whether concentrated in the pericardium or the kidney in a species-specific manner. However, some of them may be freed from those aggregations, circulate in the blood, and form distant contingent aggregations anywhere in the body, but always in response to intruders (i.e., pathogens or any other immune challenge). After that, we reviewed the incipient immunology of the Ampullariidae by critically revising the findings in Pomacea canaliculata and Marisa cornuarietis, the only ampullariid species that have been studied in this respect, and we attempted to identify the effectors and the processes in which they are involved. Particularly for P. canaliculata, which is by far the most studied species, we ask which hemocytes are involved, in which tissues or organs are integrated, and what cellular reactions to intruders this species has in common with other animals. Furthermore, we wondered what humoral factors could also integrate its internal defense system. Among the cellular defenses, we give an outstanding position to the generation of hemocyte nodules, which seems to be an important process for these snails, serving the isolation and elimination of intruders. Finally, we discuss hematopoiesis in apple snails. There have been contrasting views about some of these aspects, but we envision a hematopoietic system centered in the constitutive hemocyte islets in the ampullariid kidney.

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Hemocyte activation and nodule formation in the giant keyhole limpet, Megathura crenulata

Cited by 3 publications

References 62 publications

Histological, elemental, and ultrastructural analysis of melanin in mantle of Pacific oyster (Crassostrea gigas)

Histological, elemental, and ultrastructural analysis of melanin in mantle of Pacific oyster (Crassostrea gigas)

Pathogenesis of an experimental mycobacteriosis in an apple snail

A Dissenters’ View on AppleSnail Immunobiology

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