Yasushi Kusuoka

Yasushi Kusuoka
Lake Biwa Museum · Research

Dr. of Science

About

72
Publications
2,886
Reads
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277
Citations
Citations since 2016
2 Research Items
121 Citations
201620172018201920202021202205101520
201620172018201920202021202205101520
201620172018201920202021202205101520
201620172018201920202021202205101520
Introduction
Skills and Expertise

Publications

Publications (72)
Article
Many freshwater protists harbor unicellular green algae within their cells and these host-symbiont relationships slowly are becoming better understood. Recently, we reported that several ciliate species shared a single species of symbiotic algae. Nonetheless, the algae from different host ciliates were each distinguishable by their different genoty...
Article
Many freshwater protists harbor unicellular green algae within their cells, but little is known of their degree of integration and specificity. Using algae-targeted PCR of whole ciliate cells collected at irregular intervals over 15 months from Lake Biwa, Japan, we explored the SSU-ITS rDNA of the endosymbiotic algae and its changes over time, obta...
Article
Two oxytrichid freshwater ciliates, Apoamphisiella tihanyiensis (Gellért and Tamás, 1958) Foissner, 1997 and Notohymena australis (Foissner and O’Donoghue, 1990) Berger, 1999, were recorded for the first time in Lake Biwa, a 4-million-year-old lake located at the Shiga Prefecture in Japan. Their morphology was investigated based on observations of...
Article
Stentor polymorphus (Müller) Ehrenberg (Heterotrichea, Ciliophora) is a trumpet-form ciliate with endosymbiotic green algae (photobionts). Previous reports have indicated that this photobiont has a form typical of Chlorella Beijerinck (Trebouxiophyceae), with one chloroplast and a distinct pyrenoid. We collected S. polymorphus from an artificial po...
Article
Recent phylogenetic analyses of the peritrich genus Vorticella have suggested that it might be paraphyletic, with one Vorticella species - Vorticella microstoma grouping with the swimming peritrichs Astylozoon and Opisthonecta in a distant clade. These results were based on very limited taxon sampling and thus could not be accepted as conclusive ev...
Article
Little is known about the phylogeny of the family Vorticellidae at the generic level because few comprehensive analyses of molecular phylogenetic relationships between members of this group have, so far, been done. As a result, the phylogenetic positions of some genera that were based originally on morphological analyses remain controversial. In th...
Article
We examined the effects of predation by Nigorobuna Carassius auratus grandoculis larvae and fry, a crucian carp endemic to Lake Biwa, Japan, on the community structure of aquatic organisms in rice fields. Six experimental plots with three different rice-straw treatments in the presence/absence of stocked larvae were prepared. In each plot, the numb...
Article
The urostyloid freshwater ciliate Pseudourostyla cristata was recorded for the first time from Lake Biwa, a 4-million-year-old lake located in Shiga Prefecture, Japan. Its morphology and morphogenesis were investigated using live observation and protargol impregnation, and the SSU ribosomal RNA gene was sequenced. Based on the current observations...
Article
Full-text available
We investigated a Histiobalantium natans viridis population from the ancient Lake Biwa in Japan, using live observation, silver impregnation, and the small subunit rRNA gene sequence. The morphological and molecular data show, with high support, a close relationship of Histiobalantium, Schizocalyptra and Pleuronema, supporting the family Pleuronema...
Article
This paper includes the proposal of a new genus for a new species of peritrichous ciliate, Apocarchesium rosettum n. gen., n. sp., as well as the first description by modern techniques of another peritrich, Ophrydium eichornii Ehrenberg, 1838. The genus Apocarchesium is separated from the related genus Carchesium by the appearance of the stalk and...
Article
Full-text available
Levicoleps biwae n. gen., n. sp. was discovered in organic mud on the shore of Lake Biwa, Japan. Its morphology and small subunit rRNA gene sequence were studied with standard methods. Further, we established a terminology for the colepid armour and selected four features for genus recognition: the number of armour tiers, the structure of the tier...
Article
A distributional survey of the large branchiopod crustaceans of the rice paddies of Shiga Prefecture, Japan, was conducted by the Lake Biwa Museum in May and June of 1999 and 2000. Collecting kits were issued to over 100 lay Field Reporters, who returned all samples, usually dried, to the museum for processing. Their 242 species-lots were augmented...
Article
Vertical distributions of bacterial numbers, cell sizes, and biomass in the water of Lake Fryxell in the McMurdo Dry Valleys of the Antarctic were examined by the acridine orange direct count (AODC) method. Total bacterial numbers increased with increasing depth from 5.4×105 cells⋅ml-1 in the surface water (5.0 m depth) to 1.7×107 cells⋅ml-1 in the...
Article
Scanning electron microscope (SEM) observations of remaining stalk ends were made to distinguish emigration by telotroch formation and death by predation in sessile peritrich ciliates (protozoa). Carchesium polypinum had nail head-like stalk ends after the formation of telotrochs and Epistylis sp. had cone-shaped stalk ends. When the peritrichs wer...
Article
A computerized system was devised to trace the attachment, growth and disappearance of peritrich ciliates in an urban river. By tracing the development of each Carchesium polypinum colony in the river, it was possible to estimate the actual growth rate of this species without considering the effect of immigration. The survival and colonization rate...

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