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Solar-powered sea slugs. Mollusc/algal chloroplast symbiosis. Plant Physiol

Program in Molecular and Environmental Plant Sciences, Texas A&M University, College Station, Texas 77843-2133, USA.
Plant physiology (Impact Factor: 7.39). 06/2000; 123(1):29-38. DOI: 10.1104/pp.123.1.29
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    • "Such kleptoplastidy (i.e., sequestering of chloroplasts) is known in various organisms from protists to metazoans. Sea slugs retain the chloroplasts from consumed green algae and obtain the photosynthetic products (e.g., Green et al. 2000; Maeda et al. 2010; Rumpho et al. 2000). Dinoflagellates also retain cryptomonads as kleptoplasts (e.g., Horiguchi and Pienaar 1992; Larsen 1988); in particular, Dinophysis acuminata retains the ciliate Mesodinium rubrum that first retains chloroplasts from the cryptophyte Geminigera cryophila (Park et al. 2006). "
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    ABSTRACT: The benthic foraminifer Virgulinella fragilis Grindell and Collen 1976 has multiple putative symbioses with both bacterial and kleptoplast endobionts, possibly aiding its survival in environments from dysoxia (5-45 μmol-O2/liter) to microxia (0-5 μmol-O2/liter) and in the dark. To clarify the origin and function of V. fragilis endobionts, we used genetic analyses and transmission electron microscope observations. Virgulinella fragilis retained δ-proteobacteria concentrated at its cell periphery just beneath the cell membranes. Unlike another foraminifer Stainforthia spp., which retain many bacterial species, V. fragilis has a less variable bacterial community. This suggests that V. fragilis maintains specific intracellular bacterial flora. Unlike the endobiotic bacteria, V. fragilis kleptoplasts originated from various diatom species and are found in the interior cytoplasm. We found evidence of both retention and digestion of kleptoplasts, and of fragmentation of the kleptoplastid outer membrane that likely facilitates transport of kleptoplastid products to the host. Accumulations of mitochondria were observed encircling endobiotic bacteria. It is likely that the bacteria use host organic material for carbon oxidation. The mitochondria may use oxygen available around the δ-proteobacteria and synthesize ATP, perhaps for sulfide oxidation.This article is protected by copyright. All rights reserved.
    Journal of Eukaryotic Microbiology 07/2015; 62:454–469. DOI:10.1111/jeu.12200 · 3.22 Impact Factor
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    • "The chromophyte V. litorea has a siphonaceous morphology and succulent filaments with few distinct cross walls, while a large central vacuole is surrounded by a thin layer of multinucleate cytoplasm that contains numerous chloroplasts. This makes it easy for sea slugs to suck out large amounts of chloroplasts by puncturing the thin cell wall using their specially adapted radular tooth (Jensen et al. 1993; Rumpho et al. 2000). The V. litorea plastids are surrounded by four membranes in vivo, which have a more robust structure and function than plant plastids after isolation (Lilley et al. 1975; Kaiser et al. 1981; Seftor & Jensen 1986; Rumpho et al. 2001), and this probably contributes to their survival in the digestive tract during the uptake phase of symbiosis (Rumpho et al. 2001). "
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    ABSTRACT: The capacity of sea slugs (sacoglossans) for retaining chloroplasts from food algae provides important insights into endosymbiotic relationships and kleptoplasty. A sea slug species was captured accidentally in the Yellow Sea and identified as Placida sp. YS001 based on phylogenetic analyses of the COX1 and 16S gene sequence. Its life cycle was recorded using microscope. Photosynthetic analysis by pulse amplitude modulated fluorometry during starvation revealed shortterm functional kleptoplasty. An ultrastructural comparison of the slug and alga showed that a change in the chloroplast structure and the phagosome might correspond to short-term endosymbiosis. The horizontally transferred genes, psbO and lectin, were not cloned in the adults or eggs. This study demonstrates the morphological adaptation that occurs during short-term endosymbiotic relationships and provides fresh insights.
    Biologia 05/2014; 69(5). DOI:10.2478/s11756-014-0355-y · 0.70 Impact Factor
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    • "Wägele and Johnsen, 2001; Evertsen et al., 2007; Händeler et al., 2009; Jesus et al., 2010; Wägele et al., 2011; Middlebrooks et al., 2012; Klochkova et al., 2013) has been replacing to a large extent other methodologies such as O 2 production (e.g. Rumpho et al., 2000; Giménez-Casalduero and Muniain, 2006) and light-driven CO 2 incorporation using 14 C incubation (e.g. Trench et al., 1973; Hinde and Smith, 1975; Clark et al., 1990; Marín and Ros, 1992). "
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    ABSTRACT: Some species of sacoglossan sea slugs can maintain functional chloroplasts from specific algal food sources in the cells of their digestive diverticula. These ‘stolen’ chloroplasts (kleptoplasts) can survive in the absence of the plant cell and continue to photosynthesize, in some cases for as long as one year. Within the Metazoa, this phenomenon (kleptoplasty) seems to have only evolved among sacoglossan sea slugs. Known for over a century, the mechanisms of interaction between the foreign organelle and its host animal cell are just now starting to be unravelled. In the study of sacoglossan sea slugs as photosynthetic systems, it is important to understand their relationship with light. This work reviews the state of knowledge on autotrophy as a nutritional source for sacoglossans and the strategies they have developed to avoid excessive light, with emphasis to the behavioural and physiological mechanisms suggested to be involved in the photoprotection of kleptoplasts. A special focus is given to the advantages and drawbacks of using pulse amplitude modulated fluorometry in photobiological studies addressing sacoglossan sea slugs. Finally, the classification of photosynthetic sacoglossan sea slugs according to their ability to retain functional kleptoplasts and the importance of laboratory culturing of these organisms are briefly discussed.
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