20.500.12556/DiRROS-19636 NanoSIMS and tissue autoradiography reveal symbiont carbon fixation and organic carbon transfer to giant ciliate host The giant colonial ciliate Zoothamnium niveum harbors a monolayer of the gammaproteobacteria Cand. Thiobios zoothamnicoli on its outer surface. Cultivation experiments revealed maximal growth and survival under steady flow of high oxygen and low sulfide concentrations. We aimed at directly demonstrating the sulfur-oxidizing, chemoautotrophic nature of the symbionts and at investigating putative carbon transfer from the symbiont to the ciliate host. We performed pulse-chase incubations with 14C- and 13C-labeled bicarbonate under varying environmental conditions. A combination of tissue autoradiography and nanoscale secondary ion mass spectrometry coupled with transmission electron microscopy was used to follow the fate of the radioactive and stable isotopes of carbon, respectively. We show that symbiont cells fix substantial amounts of inorganic carbon in the presence of sulfide, but also (to a lesser degree) in the absence of sulfide by utilizing internally stored sulfur. Isotope labeling patterns point to translocation of organic carbon to the host through both release of these compounds and digestion of symbiont cells. The latter mechanism is also supported by ultracytochemical detection of acid phosphatase in lysosomes and in food vacuoles of ciliate cells. Fluorescence in situ hybridization of freshly collected ciliates revealed that the vast majority of ingested microbial cells were ectosymbionts. microbial ecology symbiosis true false true Angleški jezik Ni določen Neznano 2024-07-23 03:54:07 2024-07-24 12:15:56 2024-07-25 04:14:48 0000-00-00 00:00:00 2018 0 0 str. 714-727 Vol. 12 2018 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 2018-03-01 577 1751-7362 10.1038/s41396-018-0069-1 4610639 http://dx.doi.org/10.1038/s41396-018-0069-1 1 af126813-4885-11ef-b487-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=27136 RAZ_Volland_Jean-Marie_2018.pdf RAZ_Volland_Jean-Marie_2018.pdf 1 9965697C0AA9DF515540C424E3D3AB16 338c3edbf7f3ad3309daf55ab1218452b806f907313c52070b008a1805568874 c7d03532-4995-11ef-b487-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=27285 Nacionalni inštitut za biologijo 0 0 0