Symbiotic<i>Chlorella variabilis</i>incubated under constant dark conditions for 24 hours loses the ability to avoid digestion by host lysosomal enzymes in digestive vacuoles of host ciliate<i>Paramecium bursaria</i>

Kodama, Yuuki; Fujishima, Masahiro

doi:10.1111/1574-6941.12448

Cited by 23 publications

(18 citation statements)

References 49 publications

(67 reference statements)

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“…Animals take advantage of mitochondria to generate energy to survive; energy is primarily generated from phagocytizing and digesting food particles through intracellular or extracellular digestion [22,23]. Previous studies have found that phagocytic intracellular digestion is the evolutionary cornerstone of digestive and immune mechanisms of multicellular animals [24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Whole‐Genome Resequencing of Twenty Branchiostoma belcheri Individuals Provides a Brand‐New Variant Dataset for Branchiostoma

Lü

Han

et al. 2020

BioMed Research International

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As the extant representatives of the basal chordate lineage, amphioxi (including the genera Branchiostoma, Asymmetron and Epigonichthys) play important roles in tracing the state of chordate ancestry. Previous studies have reported that members of the Branchiostoma species have similar morphological phenotypic characteristics, but in contrast, there are high levels of genetic polymorphisms in the populations. Here, we resequenced 20 Branchiostomabelcheri genomes to an average depth of approximately 12.5X using the Illumina HiSeq 2000 platform. In this study, over 52 million variations (~12% of the total genome) were detected in the B. belcheri population, and an average of 12.8 million variations (~3% of the total genome) were detected in each individual, confirming that Branchiostoma is one of the most genetically diverse species sequenced to date. Demographic inference analysis highlighted the role of historical global temperature in the long-term population dynamics of Branchiostoma, and revealed a population expansion at the Greenlandian stage of the current geological epoch. We detected 594 Single nucleotide polymorphism and 148 Indels in the Branchiostoma mitochondrial genome, and further analyzed their genetic mutations. A recent study found that the epithelial cells of the digestive tract in Branchiostoma can directly phagocytize food particles and convert them into absorbable nontoxic nutrients using powerful digestive and immune gene groups. In this study, we predicted all potential mutations in intracellular digestion-associated genes. The results showed that most “probably damaging” mutations were related to rare variants (MAF < 0.05) involved in strengthening or weakening the intracellular digestive capacity of Branchiostoma. Due to the extremely high number of polymorphisms in the Branchiostoma genome, our analysis with a depth of approximately 12.5X can only be considered a preliminary analysis. However, the novel variant dataset provided here is a valuable resource for further investigation of phagocytic intracellular digestion in Branchiostoma and determination of the phenotypic and genotypic features of Branchiostoma.

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Section: Introductionmentioning

confidence: 99%

Whole‐Genome Resequencing of Twenty Branchiostoma belcheri Individuals Provides a Brand‐New Variant Dataset for Branchiostoma

Lü

Han

et al. 2020

BioMed Research International

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“…Light availability is important for mixotrophs. For example, Chlorella symbionts provide photosynthetic products to their host under light conditions (Shibata et al, 2016), but they lost their ability to resist host digestion in darkness (Kodama and Fujishima, 2014). Heavy metals also affect protistan ingestion rates (Al-Rasheid and Sleigh, 1994) and physiology (Kim et al, 2011).…”

Section: Discussionmentioning

confidence: 99%

Environmental Factors and Pollution Stresses Select Bacterial Populations in Association With Protists

Zou

Zhang

et al. 2020

Front. Mar. Sci.

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Digestion-resistant bacteria (DRB) refer to the ecological bacterial group that can be ingested, but not digested by protistan grazers, thus forming a specific type of bacteria-protist association. To test the hypothesis that the environment affects the assembly of DRB in protists, a mixotrophic ciliate, Paramecium bursaria, and a heterotrophic ciliate, Euplotes vannus, were reared at different temperatures, light conditions, and concentration gradients of antibiotic oxytetracycline and heavy metals. Community profiling indicated that the composition of DRB in both species varied significantly across the manipulated conditions, except for in P. bursaria under light/dark treatments. Clone library analysis of bacterial 16S rRNA genes showed that DRB were diverse. Pseudomonas became more abundant during the warmer treatment of P. bursaria, whereas the dominance of Pseudoalteromonas weakened and Vibrio became more abundant in E. vannus at a higher temperature. During the treatment of diel light:dark cycles, Aestuariibacter and Alteromonas were selected for in E. vannus but not Pseudoalteromonas, which was highly represented in the all-light and alldark treatments. In contrast, P. bursaria consistently hosted Nevskia, Curvibacter, and Asticcacaulis under all light conditions. There were many bacterial species co-resistant to oxytetracycline and to protistan digestion, in which Sphingomonas, Alteromonas, Aestuariibacter, Puniceicoccaceae (Verrucomicrobia), Pseudomonas, and Sulfitobacter were frequently abundant. Flectobacillus and Aestuariibacter were major lead-resistant bacteria associated with the studied protists. Acinetobacter and Hydrogenophaga were abundant in the P. bursaria treated with a high dose of mercury. Aestuariibacter was found as a dominant group of DRB in E. vannus across all cadmium treatments. In summary, this study demonstrates for the first time that environmental stress selects for bacterial populations associated with protists and that there are diverse bacterial species that not only are resistant to pollution stresses but can also survive protistan predation. This work highlights that bacteria-protists associations need to be taken into account in understanding ecological and environmental issues, such as resilience of bacterial community and function, microbial co-occurrence, and quantity and distribution of antibiotic resistant bacteria and genes.

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“…Our previous study showed that the increased number of acidic vacuoles of the symbiotic Chlorella spp. causes preferential digestion by the host lysosomal digestive enzymes during the early infection process ( Kodama and Fujishima, 2014 ). Kuchitsu et al (1987) showed that the algal vacuoles increase in number at the stationary phase compared with the algae in the log phase.…”

Section: Discussionmentioning

confidence: 99%

Differences in infectivity between endosymbiotic Chlorella variabilis cultivated outside host Paramecium bursaria for 50 years and those immediately isolated from host cells after one year of reendosymbiosis

Kodama

Fujishima

2015

Biology Open

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Chlorella variabilis strain NC64A is an intracellular photobiont of the ciliate Paramecium bursaria. NC64A was isolated from P. bursaria nearly 50 years ago and was thereafter cultivated outside the host. This study was undertaken to detect changes in its infectivity to P. bursaria and its auxotrophy for growth outside the host induced during long-term cultivation. NC64A can grow in Modified Bold's Basal Medium but not in C medium, whereas another symbiotic Chlorella variabilis strain, 1N, that was recently isolated from the host grew in C medium but not in Modified Bold's Basal Medium. With regards infectivity, NC64A in the logarithmic phase of growth showed low infectivity to alga-removed P. bursaria cells, whereas those in the early stationary phase showed high infectivity of about 30%. Those in the decay phase of growth showed no infectivity. Results show that NC64A has infectivity, but the infection rate depends on their culture age in the growth curve. Furthermore, NC64A that had been re-infected to P. bursaria for more than one year and isolated from the host showed a nearly 100% infection rate, which indicates that NC64A can recover its infectivity by re-infection to P. bursaria.

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SymbioticChlorella variabilisincubated under constant dark conditions for 24 hours loses the ability to avoid digestion by host lysosomal enzymes in digestive vacuoles of host ciliateParamecium bursaria

Cited by 23 publications

References 49 publications

Whole‐Genome Resequencing of Twenty Branchiostoma belcheri Individuals Provides a Brand‐New Variant Dataset for Branchiostoma

Whole‐Genome Resequencing of Twenty Branchiostoma belcheri Individuals Provides a Brand‐New Variant Dataset for Branchiostoma

Environmental Factors and Pollution Stresses Select Bacterial Populations in Association With Protists

Differences in infectivity between endosymbiotic Chlorella variabilis cultivated outside host Paramecium bursaria for 50 years and those immediately isolated from host cells after one year of reendosymbiosis

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