Fig 3 - uploaded by Theerakamol Pengsakul
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Oncomelania hupensis haemolymphoctes of three different nucleus sizes; large (arrow 1), medium (arrow 2) and small (arrow 3) (Scanning Electron Microscopy micrograph) Bar = 10 µm.
Source publication
Information concerning morphological and functional basis of defense cells of Oncomelania hupensis (Gastropoda: Pomatiopsidae), intermediate host of schistosomiasis parasite, Schistosoma japonicum, observed through optical microscopy (light and fluorescence); scanning electron microscopy (SEM); and transmission electron microscopy (TEM) is presente...
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... also could be separated into three size groups: large, medium, and small, with diameter ranges of 8.1-8.6 µm, 5.5-6.0 µm, and 4.2- 4.7 µm, respectively. The SEM micrographs showed round shaped nucleus of haemo-lymphocytes with rough surface but the cytoplasm was not visible. The SEM of haemo-lymphocytes also showed the three sizes of nucleus (Fig. 3), with their size ranges similar to the ones observed using fluorescent microscopy ...
Citations
... However, detailed analysis on cell size, ultrastructural characteristics, extent of granularity, cell surface and biomedical markers indicated that hemocyte populations are very heterogeneous (Martins-Souza et al., 2009). More interestingly, some studies reported that the hemocytes of O. hupensis can be divided into three different types (small, medium and large) based mainly upon nucleus size, and showed that the hemocytes may play an important role in the snail immune defense response to parasite invasion (Tang et al., 2009(Tang et al., , 2012(Tang et al., , 2013Pengsakul et al., 2013a). ...
... Therefore, the morphological and structural characterizations of hemocytes are fundamental for a better understanding of the interaction between snail and parasite. Although the nomenclature of hemocytes in the Mollusca has not been standardized yet, many studies on the classification of hemocytes have been reported, mostly based on ultrastructure (Matricon-Gondran and Letorcart, 1999;Pengsakul et al., 2013a), flow cytometry (Martins-Souza et al., 2009) and biochemical analysis (Granath and Yoshino, 1983). In this study, we performed SEM, TEM and flow cytometry Fig. 7. Oncomelania hupensis macrophage migration inhibitory factor (OhMIF) is implicated in maturity and differentiation of hemocytes. ...
Schistosomiasis, caused by parasitic trematodes of the genus Schistosoma, remains a devastating public health problem, with over 200 million people infected and 779 million people at risk worldwide, especially in developing countries. The freshwater amphibious snail Oncomelania hupensis is the obligate intermediate host of Schistosoma japonicum. This unique and long-standing host-parasite interaction highlights the biomedical importance of the molecular and cellular mechanisms involved in the snail immune defense response against schistosome infection. In recent years, a number of immune-related effectors and conserved signalling pathways have been identified in molluscs, especially in Biomphalaria glabrata, which is an intermediate host for Schistosoma mansoni, but few have been reported in O. hupensis. Here we have successfully identified and functionally characterized a homologue of mammalian macrophage migration inhibitory factor (MIF) from O. hupensis (OhMIF). MIF, a pleiotropic regulator of innate immunity, is a constitutively expressed mediator in the host’s antimicrobial defense system and stress response that promotes the pro-inflammatory functions of immune cells. In the present study, we detected the distribution of OhMIF in various snail tissues, especially in immune cell types (hemocytes) and found that OhMIF displays significantly increased expression in snails following challenge with S. japonicum. Knockdown of OhMIF was conducted successfully in O. hupensis and significantly reduced the percentage of phagocytic cell populations in circulating hemocytes. Furthermore, OhMIF is not only implicated in the activation and differentiation of hemocytes, but also essential to promote the migration and recruitment of hemocytes towards the infected sites. These results provide the first known functional evidence in exploring the molecular mechanisms involved in the O. hupensis innate immune defense response to the parasite S. japonicum and help to better understand the complex host-parasite interaction.
