Abstract
Large benthic foraminifera are unicellular calcifying reef organisms that can form symbiotic relationships with a range of different microalgae. However, the cellular functions, such as symbiosis and calcification, and other aspects of cellular physiology in large benthic foraminifera are not fully understood. Amphisorus kudakajimensis was used as a model to determine the detailed cellular characteristics of large benthic foraminifera. We used calcein acetoxymethyl ester (calcein AM) as a fluorescent indicator for live confocal imaging. We demonstrated that calcein AM is a useful fluorescent indicator to stain the fine network of reticulopodia and the cytoplasm in living A. kudakajimensis. We showed that at least two types of reticulopodia exist in A. kudakajimensis: the straight bundle of reticulopodia that spreads from the aperture and the fine reticulopodia along the surface of the aperture and chamber walls. The cytoplasm in outer chambers was highly branched and contained a few dinoflagellates. In contrast, the inner chamberlets contained condensed cytoplasm and many dinoflagellates, suggesting that the cytoplasm of A. kudakajimensis performs different functions based on its location within the large test. Our confocal detailed image analysis provides real-time cellular morphology and cell physiology of living foraminifera.
Highlights
Foraminifera are single-celled protists, and modern taxonomies rank the group as a phylum or subphylum [1]
Bright-field images of A. kudakajimensis showed the spreading of reticulopodia outside of the test and the localization of numerous dinoflagellates to inner parts of the test, which were dark in appearance
We could not obtain a clear image of the cytoplasm in each of the chamberlets in the outer chambers (Fig 1A)
Summary
Foraminifera are single-celled protists, and modern taxonomies rank the group as a phylum or subphylum [1]. The main functions of reticulopodia include food capture [7], motility and attachment [8,9], test construction [6, 10,11], and, possibly, some aspects of reproduction [12,13]. We performed a simple staining method to visualize the cytoplasm and reticulopodia within live Amphisorus kudakajimensis (Gudmundsson, 1994), which is a large benthic foraminifera (LBF) with a porcelaneous shell [25]. For this purpose, we utilized calcein acetoxymethyl ester (calcein AM). Based on these chemical properties, calcein AM has a broad range of applications in physiological studies, such as viability assays [30], cytotoxicity assays [31], cell volume studies [32], and the study of chemotaxis [33]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
