Freeze‐Fracture and Cytoehemical Studies on the in Vitro Cyst Form of Reptilian <i>Blastocystis pythoni</i>

Yoshikawa, Hideki; Nagashima, M; Morimoto, Keiko; Yamanouti, Yasuko; Yap, E. H.; Singh, Mulkit

doi:10.1111/j.1550-7408.2003.tb00108.x

Cited by 11 publications

(5 citation statements)

References 22 publications

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“…In general, stramenopiles utilize β-glucans as storage polysaccharides and lack starch or glycogen metabolism-related genes, as evidenced by the stramenopile genomes examined so far (diatoms, brown algae, and oomycetes) [ 86 , 87 ]. Our results are consistent with previous microscopic observations of glycogen-like particles in the cytoplasm of several species of Blastocystis [ 88 – 90 ].…”

Section: Resultssupporting

confidence: 94%

Extreme genome diversity in the hyper-prevalent parasitic eukaryote Blastocystis

et al. 2017

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Blastocystis is the most prevalent eukaryotic microbe colonizing the human gut, infecting approximately 1 billion individuals worldwide. Although Blastocystis has been linked to intestinal disorders, its pathogenicity remains controversial because most carriers are asymptomatic. Here, the genome sequence of Blastocystis subtype (ST) 1 is presented and compared to previously published sequences for ST4 and ST7. Despite a conserved core of genes, there is unexpected diversity between these STs in terms of their genome sizes, guanine-cytosine (GC) content, intron numbers, and gene content. ST1 has 6,544 protein-coding genes, which is several hundred more than reported for ST4 and ST7. The percentage of proteins unique to each ST ranges from 6.2% to 20.5%, greatly exceeding the differences observed within parasite genera. Orthologous proteins also display extreme divergence in amino acid sequence identity between STs (i.e., 59%–61% median identity), on par with observations of the most distantly related species pairs of parasite genera. The STs also display substantial variation in gene family distributions and sizes, especially for protein kinase and protease gene families, which could reflect differences in virulence. It remains to be seen to what extent these inter-ST differences persist at the intra-ST level. A full 26% of genes in ST1 have stop codons that are created on the mRNA level by a novel polyadenylation mechanism found only in Blastocystis. Reconstructions of pathways and organellar systems revealed that ST1 has a relatively complete membrane-trafficking system and a near-complete meiotic toolkit, possibly indicating a sexual cycle. Unlike some intestinal protistan parasites, Blastocystis ST1 has near-complete de novo pyrimidine, purine, and thiamine biosynthesis pathways and is unique amongst studied stramenopiles in being able to metabolize α-glucans rather than β-glucans. It lacks all genes encoding heme-containing cytochrome P450 proteins. Predictions of the mitochondrion-related organelle (MRO) proteome reveal an expanded repertoire of functions, including lipid, cofactor, and vitamin biosynthesis, as well as proteins that may be involved in regulating mitochondrial morphology and MRO/endoplasmic reticulum (ER) interactions. In sharp contrast, genes for peroxisome-associated functions are absent, suggesting Blastocystis STs lack this organelle. Overall, this study provides an important window into the biology of Blastocystis, showcasing significant differences between STs that can guide future experimental investigations into differences in their virulence and clarifying the roles of these organisms in gut health and disease.

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Section: Resultssupporting

confidence: 94%

Extreme genome diversity in the hyper-prevalent parasitic eukaryote Blastocystis

et al. 2017

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“…Alveolates are members of the SAR (which stands for Stramenopiles, alveolates, and Rhizaria) which contain two other major groups: the Stramenopiles and Rhizaria. Both of these are "-glucan accumulators and accumulate neither glycogen nor starch (with the noticeable exception of the Blastocystis glycogenaccumulating unicellular stramenopile gut parasite (Yoshikawa et al 2003)). It must be stressed that "-1,3-linked storage "-glucans are widely distributed in the bikont branch of the eukaryotes (Fig.…”

Section: The Bacterial Eukaryote and Archeal Domainsmentioning

confidence: 99%

The Transition from Glycogen to Starch Metabolism in Cyanobacteria and Eukaryotes

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Colleoni

Arias

2015

Starch

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'-1,4-linked glucan chains branched through '-1,6 glucosidic lineages define the most frequently found storage polysaccharides in living cells. These glucans come in two very distinct forms known as glycogen and starch. The small water-soluble glycogen particles distribute widely in Archaea, Bacteria, and heterotrophic eukaryotes, while semicrystalline solid starch seems to be restricted to photosynthetic eukaryotes. This review focusses on the so-called glycosylnucleotide-dependent pathway of starch and glycogen synthesis. Through comparative biochemistry of storage polysaccharide metabolism in distinct clades, we will review the evidence sustaining that starch has evolved from preexisting glycogen metabolism several times during the evolution of photosynthetic eukaryotes and cyanobacteria. This review will also describe the possible function of storage polysaccharide metabolism in establishing metabolic symbiosis during plastid endosymbiosis. We will detail the evidence sustaining that storage polysaccharide metabolism was used by three distinct organisms to establish a tripartite symbiosis that facilitated metabolic integration of free-living cyanobacteria into evolving organelles.

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“…In contrast, oral inoculation of the RN94-9 strain was able to infect rats due to the presence of cysts in cultured organisms. Since only the Blastocystis isolates from rats and a reptile were known to produce a considerable number of cysts in the in vitro culture (Chen et al 1999;Yoshikawa et al 2003bYoshikawa et al , 2004d, intracecal inoculation was performed to clarify the infectivity in chickens of six isolates from the three different species of birds. In addition, Blastocystis is known to be genetically a polymorphic organism, hence, two different genotypes among the Blastocystis isolates from the same host species were used in this study (Table 1).…”

Section: Resultsmentioning

confidence: 99%

“…To clarify the cyst form in the feces of the animals, fresh fecal samples from each animal were collected every day and treated twice with distilled water for 1 h, because only the cyst form is known to tolerate fluctuations in osmotic pressure Yoshikawa et al 2003b). After the centrifugation, the sediments were resuspended in the liquid medium and cultured at 37°C.…”

Section: Examination Of Blastocystis Infection In Chicksmentioning

confidence: 99%

Infectivity of Blastocystis isolates from chickens, quails and geese in chickens

et al. 2005

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The infectivity of six Blastocystis isolates obtained from two domestic chickens, two Japanese quails and two domestic geese, were examined in 1-week-old male chicks. All six isolates were able to infect the chicks via the intracecal inoculation of 1x10(6) cells of cultured organisms. Since the infected chicks discharged many cysts in their feces, the infectivity of the concentrated cysts in chicks was compared among three isolates from different bird species. The CK86-1 and QQ93-3 isolates, which were obtained from a chicken and a quail, respectively, were successfully infected in chicks by orally inoculating with 1x10(2)-1x10(6) cysts. On the other hand, the AC03-1 isolate from a goose required more cysts to infect the chicks, from 1x10(3) cysts to 1x10(6) cysts. In addition, when an uninfected normal chick was housed with five experimentally inoculated chicks with cysts of the QQ93-3 isolate, the normal chick became infected, indicating the fecal-oral transmission of the cyst form among the birds. These results show that the transmission of Blastocystis infection occurs easily between the same or different bird species. Therefore, the proposal of new Blastocystis species on the basis of different avian host species is problematic.

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Freeze‐Fracture and Cytoehemical Studies on the in Vitro Cyst Form of Reptilian Blastocystis pythoni

Cited by 11 publications

References 22 publications

Extreme genome diversity in the hyper-prevalent parasitic eukaryote Blastocystis

Extreme genome diversity in the hyper-prevalent parasitic eukaryote Blastocystis

The Transition from Glycogen to Starch Metabolism in Cyanobacteria and Eukaryotes

Infectivity of Blastocystis isolates from chickens, quails and geese in chickens

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