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Yuuki Kodama - One of the best experts on this subject based on the ideXlab platform.
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symbiotic chlorella variabilis incubated under constant dark conditions for 24 hours loses the ability to avoid digestion by host lysosomal enzymes in digestive vacuoles of host ciliate paramecium bursaria
FEMS Microbiology Ecology, 2014Co-Authors: Yuuki KodamaAbstract:Endosymbiosis between symbiotic Chlorella and alga-free Paramecium bursaria cells can be induced by mixing them. To establish the endosymbiosis, Algae must acquire temporary resistance to the host lysosomal enzymes in the digestive vacuoles (DVs). When symbiotic Algae isolated from the alga-bearing paramecia are kept under a constant dark conditions for 24 h before mixing with the alga-free paramecia, almost all Algae are digested in the host DVs. To examine the cause of algal acquisition to the host lysosomal enzymes, the isolated Algae were kept under a constant light conditions with or without a photosynthesis inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea for 24 h, and were mixed with alga-free paramecia. Unexpectedly, most of the Algae were not digested in the DVs irrespective of the presence of the inhibitor. Addition of 1 mM maltose, a main photosynthetic product of the symbiotic Algae or of a supernatant of the isolated Algae kept for 24 h under a constant light conditions, did not rescue the algal digestion in the DVs. These observations reveal that unknown factors induced by light are a prerequisite for algal resistance to the host lysosomal enzymes.
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Localization of attachment area of the symbiotic Chlorella variabilis of the ciliate Paramecium bursaria during the algal removal and reinfection
Symbiosis, 2013Co-Authors: Yuuki KodamaAbstract:Chlorella spp. and ciliate Paramecium bursaria share a mutual symbiosis. However, both alga-removed P. bursaria and isolated symbiotic Algae can grow independently. Additionally, mixing them experimentally can cause algal reinfection through host phagocytosis. Although the symbiotic algal localization beneath the host cell cortex is a prerequisite phenomenon for maintenance of the relationship of their endosymbiosis, how and where the Algae locate beneath the host cell cortex remains unknown. To elucidate this phenomenon, algal distribution patterns during algal removal and reinfection were observed. During algal removal, Algae at the host anterior cortex were easier to remove than at the posterior and ventral or dorsal cortex areas. During algal reinfection, the Algae after separation from the host digestive vacuoles tended to localize beneath the host ventral or dorsal cortex more readily than that at other cortices. Algae that reinfected trichocyst-removed paramecia didn’t show this localization. Trichocyst-discharge experiments clarified that trichocysts of the anterior cortex are difficult to remove. In 14 strains of P. bursaria , some of the paramecia lacked their symbiotic Algae at the anterior cortex. These observations demonstrate that symbiotic Algae of P. bursaria are difficult to localize at the anterior cortex and that they are easy to remove from the area.
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endosymbiosis of chlorella species to the ciliate paramecium bursaria alters the distribution of the host s trichocysts beneath the host cell cortex
Protoplasma, 2011Co-Authors: Yuuki Kodama, Masahiro FujishimaAbstract:Each symbiotic Chlorella of the ciliate Paramecium bursaria is enclosed in a perialgal vacuole membrane derived from the host digestive vacuole membrane. Alga-free paramecia and symbiotic Algae can grow independently. Mixing them experimentally can cause reinfection. Earlier, we reported that the symbiotic Algae appear to push the host trichocysts aside to become fixed beneath the host cell cortex during the algal reinfection process. Indirect immunofluorescence microscopy with a monoclonal antibody against the trichocysts demonstrates that the trichocysts change their locality to form algal attachment sites and decrease their density beneath the host cell cortex through algal reinfection. Transmission electron microscopy to detect acid phosphatase activity showed that some trichocysts near the host cell cortex are digested by the host lysosomal fusion during algal reinfection. Removal of Algae from the host cell using cycloheximide recovers the trichocyst's arrangement and number near the host cell cortex. These results indicate that symbiotic Algae compete for their attachment sites with preexisting trichocysts and that the Algae have the ability to ensure algal attachment sites beneath the host cell cortex.
Gang Pan - One of the best experts on this subject based on the ideXlab platform.
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switching harmful algal blooms to submerged macrophytes in shallow waters using geo engineering methods evidence from a 15n tracing study
Environmental Science & Technology, 2018Co-Authors: Honggang Zhang, Yuanyuan Shang, Tao Lyu, Jun Chen, Gang PanAbstract:Switching the dominance from Algae to macrophytes is crucial for lake management of human-induced eutrophication. Nutrients from algal sources can be utilized in the process of transition from algal blooms to macrophytes, thereby mitigating eutrophication. However, this process rarely occurs in algal bloom dominated waters. Here, we examined the hypothesis that the transition of algal blooms to macrophytes and the transfer of nutrients from Algae at different temperatures (8 and 25 °C) can be facilitated by using a geo-engineering method. The results showed that the combination of flocculation and capping treatment could not only remove Microcystis aeruginosa blooms from eutrophic waters but also facilitate algal decomposition and incorporation into a submerged macrophyte (Potamogeton crispus) biomass. The flocculation-capping treatment could trigger algal cell lysis. As compared with the control groups, the photosynthesis and respiration rate of Algae were inhibited and chlorophyll-a (Chl-a) concentratio...
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Switching Harmful Algal Blooms to Submerged Macrophytes in Shallow Waters Using Geo-engineering Methods: Evidence from a 15N Tracing Study
2018Co-Authors: Honggang Zhang, Yuanyuan Shang, Tao Lyu, Jun Chen, Gang PanAbstract:Switching the dominance from Algae to macrophytes is crucial for lake management of human-induced eutrophication. Nutrients from algal sources can be utilized in the process of transition from algal blooms to macrophytes, thereby mitigating eutrophication. However, this process rarely occurs in algal bloom dominated waters. Here, we examined the hypothesis that the transition of algal blooms to macrophytes and the transfer of nutrients from Algae at different temperatures (8 and 25 °C) can be facilitated by using a geo-engineering method. The results showed that the combination of flocculation and capping treatment could not only remove Microcystis aeruginosa blooms from eutrophic waters but also facilitate algal decomposition and incorporation into a submerged macrophyte (Potamogeton crispus) biomass. The flocculation-capping treatment could trigger algal cell lysis. As compared with the control groups, the photosynthesis and respiration rate of Algae were inhibited and chlorophyll-a (Chl-a) concentrations were significantly reduced in the flocculation-capping treatment groups. The 15N tracing study revealed that 3.3% and 34.8% of Algae-derived nitrogen could be assimilated by Potamogeton crispus at 8 and 25 °C, respectively. The study demonstrated that the flocculation-capping method can facilitate the switchover from Algae- to the macrophyte-dominated state, which is crucial for restoring the aquatic ecosystem
Matthew P Nelsen - One of the best experts on this subject based on the ideXlab platform.
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dissociation and horizontal transmission of codispersing lichen symbionts in the genus lepraria lecanorales stereocaulaceae
New Phytologist, 2007Co-Authors: Matthew P Nelsen, Andrea GargasAbstract:Summary • Lichenized fungi of the genus Lepraria lack ascomata and conidiomata, and symbionts codisperse by soredia. Here, it is determined whether algal symbionts associated with Lepraria are monophyletic, and whether fungal and algal phylogenies are congruent, both of which are indicative of a long-term, continuous association between symbionts. • The internal transcribed spacer (ITS) and part of the actin type I locus were sequenced from Algae associated with Lepraria, and the fungal ITS and mitochondrial small subunit (mtSSU) were sequenced from fungal symbionts. Phylogenetic analyses tested for monophyly of algal symbionts and congruence between algal and fungal phylogenies. • Algae associated with Lepraria were not monophyletic, and identical Algae associated with different Lepraria individuals and species. Algal and fungal phylogenies were not congruent, suggesting a lack of strict codiversification. • This study suggests that associations between symbionts are not strictly maintained over evolutionary time. The ability to switch partners may provide benefits similar to genetic recombination, which may have helped this lineage persist.
Masahiro Fujishima - One of the best experts on this subject based on the ideXlab platform.
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endosymbiosis of chlorella species to the ciliate paramecium bursaria alters the distribution of the host s trichocysts beneath the host cell cortex
Protoplasma, 2011Co-Authors: Yuuki Kodama, Masahiro FujishimaAbstract:Each symbiotic Chlorella of the ciliate Paramecium bursaria is enclosed in a perialgal vacuole membrane derived from the host digestive vacuole membrane. Alga-free paramecia and symbiotic Algae can grow independently. Mixing them experimentally can cause reinfection. Earlier, we reported that the symbiotic Algae appear to push the host trichocysts aside to become fixed beneath the host cell cortex during the algal reinfection process. Indirect immunofluorescence microscopy with a monoclonal antibody against the trichocysts demonstrates that the trichocysts change their locality to form algal attachment sites and decrease their density beneath the host cell cortex through algal reinfection. Transmission electron microscopy to detect acid phosphatase activity showed that some trichocysts near the host cell cortex are digested by the host lysosomal fusion during algal reinfection. Removal of Algae from the host cell using cycloheximide recovers the trichocyst's arrangement and number near the host cell cortex. These results indicate that symbiotic Algae compete for their attachment sites with preexisting trichocysts and that the Algae have the ability to ensure algal attachment sites beneath the host cell cortex.
Cory D Bishop - One of the best experts on this subject based on the ideXlab platform.
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phylogenetic analysis of algal symbionts associated with four north american amphibian egg masses
PLOS ONE, 2014Co-Authors: Eunsoo Kim, Yuan Lin, Ryan Kerney, Lili Blumenberg, Cory D BishopAbstract:Egg masses of the yellow-spotted salamander Ambystoma maculatum form an association with the green alga “Oophila amblystomatis” (Lambert ex Wille), which, in addition to growing within individual egg capsules, has recently been reported to invade embryonic tissues and cells. The binomial O. amblystomatis refers to the Algae that occur in A. maculatum egg capsules, but it is unknown whether this population of symbionts constitutes one or several different algal taxa. Moreover, it is unknown whether egg masses across the geographic range of A. maculatum, or other amphibians, associate with one or multiple algal taxa. To address these questions, we conducted a phylogeographic study of Algae sampled from egg capsules of A. maculatum, its allopatric congener A. gracile, and two frogs: Lithobates sylvatica and L. aurora. All of these North American amphibians form associations with Algae in their egg capsules. We sampled Algae from egg capsules of these four amphibians from localities across North America, established representative algal cultures, and amplified and sequenced a region of 18S rDNA for phylogenetic analysis. Our combined analysis shows that symbiotic Algae found in egg masses of four North American amphibians are closely related to each other, and form a well-supported clade that also contains three strains of free-living chlamydomonads. We designate this group as the ‘Oophila’ clade, within which the symbiotic Algae are further divided into four distinct subclades. Phylogenies of the host amphibians and their algal symbionts are only partially congruent, suggesting that host-switching and co-speciation both play roles in their associations. We also established conditions for isolating and rearing algal symbionts from amphibian egg capsules, which should facilitate further study of these egg mass specialist Algae.
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intracellular invasion of green Algae in a salamander host
Proceedings of the National Academy of Sciences of the United States of America, 2011Co-Authors: Ryan Kerney, Eunsoo Kim, Cory D Bishop, Roger P Hangarter, Aaron A Heiss, Brian K HallAbstract:The association between embryos of the spotted salamander (Ambystoma maculatum) and green Algae (“Oophila amblystomatis” Lamber ex Printz) has been considered an ectosymbiotic mutualism. We show here, however, that this symbiosis is more intimate than previously reported. A combination of imaging and algal 18S rDNA amplification reveals algal invasion of embryonic salamander tissues and cells during development. Algal cells are detectable from embryonic and larval Stages 26–44 through chlorophyll autofluorescence and algal 18S rDNA amplification. Algal cell ultrastructure indicates both degradation and putative encystment during the process of tissue and cellular invasion. Fewer algal cells were detected in later-stage larvae through FISH, suggesting that the decline in autofluorescent cells is primarily due to algal cell death within the host. However, early embryonic egg capsules also contained encysted algal cells on the inner capsule wall, and algal 18S rDNA was amplified from adult reproductive tracts, consistent with oviductal transmission of Algae from one salamander generation to the next. The invasion of Algae into salamander host tissues and cells represents a unique association between a vertebrate and a eukaryotic alga, with implications for research into cell–cell recognition, possible exchange of metabolites or DNA, and potential congruence between host and symbiont population structures.
