Publications by authors named "Mizuki Sasaki"

28 Publications

  • Page 1 of 1

Brachylaima phaedusae n. sp. (Trematoda: Brachylaimidae) from door snails in Japan.

Parasitol Int 2021 Sep 15;86:102469. Epub 2021 Sep 15.

Kyushu Mollusc Study Society, 4-21-17 Konan, Miyazaki, Miyazaki 880-0944, Japan.

The metacercarial infections of door snails (Gastropoda: Clausiliidae) with unknown species of the genus Brachylaima (Trematoda: Brachylaimidae) have recently been reported in eastern Honshu and Kyushu, Japan. A large scale snail survey was carried out to clarify their taxonomic status. From the period of 2015 to 2020, a total of 1239 land snails (768 door snails and 471 others) were collected from 32 localities in Honshu, Shikoku, and Kyushu. The resulting trematode isolates were identified as Brachylaima sp. by mitochondrial DNA barcoding. The sporocysts were found only a few from Megalophaedusa sublunellata (Clausiliidae), Tauphaedusa subaculus (Clausiliidae), and Aegista trochula (Camaenidae), while the metacercariae were frequently detected from 14 species of Clausiliidae and 2 species of other families. Although Brachylaima sp. showed a broad range of intermediate hosts, door snails seem to be very important to drive the life cycle. The gravid adults of Brachylaima sp. was experimentally raised from metacercariae using immunosuppressed mice. Morphological, phylogenetical, and ecological considerations prompted us to propose Brachylaima phaedusae n. sp. for this unknown species. The definitive hosts of the new species are completely unknown. The wide geographic distribution and high genetic diversity of the new species suggest a possibility that the definitive host is ground-foraging birds, which prefer door snails.
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http://dx.doi.org/10.1016/j.parint.2021.102469DOI Listing
September 2021

Survey to detect tick-borne encephalitis virus from human-feeding ticks in Hokkaido, Japan.

J Dermatol 2021 Jul 23;48(7):1094-1097. Epub 2021 Mar 23.

National Research Center for the Control and Prevention of Infectious Diseases (CCPID, Nagasaki University, Nagasaki, Japan.

A tick infestation is one of the most common arthropod-related skin diseases in Hokkaido, the northernmost island of Japan. Ticks also act as an infectious disease vector for humans. Tick-borne encephalitis (TBE), a highly mortal central nervous system infection caused by TBE virus (TBEV), has sporadically occurred there recently. However, there have been no epidemiological data on the current surveillance of human tick bites and the prevalence of TBEV in human-feeding ticks. This study was performed to clarify those indeterminate issues. One hundred and fifty-three ixodid ticks feeding on humans were collected from 150 outpatients in Hokkaido during the season of April to August 2018. None of the cases showed any infectious symptoms. These ticks were morphologically identified to species, and a cytopathic assay on baby hamster kidney cells was carried out to detect TBEV from each tick. The tick collection consisted of 108 Ixodes persulcatus (one nymph and 107 adult females), 44 female Ixodes ovatus, and one female Haemaphysalis japonica. No tick extracts showed positive results of the cytopathic assay, suggesting the non-existence of TBEV in the present specimens. However, the survey to detect TBEV from human-feeding ticks is still important to monitor the occurrence of TBE, because human tick bites by I. ovatus, a possible vector of TBEV, are increasing even in the northern and eastern areas of Hokkaido.
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http://dx.doi.org/10.1111/1346-8138.15865DOI Listing
July 2021

Trematode diversity in freshwater snails from a stopover point for migratory waterfowls in Hokkaido, Japan: An assessment by molecular phylogenetic and population genetic analyses.

Parasitol Int 2021 Aug 20;83:102329. Epub 2021 Mar 20.

Department of Parasitology, Asahikawa Medical University, Asahikawa, Hokkaido 078-8510, Japan.

The cryptic diversity of trematodes was evaluated in the Nagayama-Shinkawa River, an artificial canal of the Ishikari River System of Hokkaido, Japan. Numerous migratory waterfowls use the canal as a stopover point in every spring season. The lymnaeid snail, Radix auricularia, and the semisulcospirid snail, Semisulcospira libertina, colonize the static and flowing water areas, respectively. The trematode fauna of the two snails was assessed by molecular phylogenetic and population genetic analyses. Each of distinctive clades in mitochondrial DNA trees was arbitrarily set as a species. In total, 14 species of the families Diplostomidae, Echinostomatidae, Notocotylidae, Plagiorchiidae, and Strigeidae occurred in R. auricularia, wherease S. libertina harbored 10 species of the families Echinochasmidae, Heterophyidae, Notocotylidae, and Lecithodendridae and Cercaria creta, an unclassified species whose adult stage is still unknown. The species diversity of the larval trematodes could be recognized as a "hot spot", suggesting that the seasonal visit of waterfowls is very important to spread trematodes and to keep their diversity. A high intraspecific genetic diversity was observed in the echinostomatid, notocotylid, echinochasmid, and heterophyid species, whose definitive hosts include birds. It seems likely that each of the parasite populations is always disturbed by repeated visits of waterfowls.
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http://dx.doi.org/10.1016/j.parint.2021.102329DOI Listing
August 2021

Notocotylus ikutai n. sp. (Digenea: Notocotylidae) from lymnaeid snails and anatid birds in Hokkaido, Japan.

Parasitol Int 2021 Aug 6;83:102318. Epub 2021 Mar 6.

Department of Parasitology, Asahikawa Medical University, Asahikawa, Hokkaido 078-8510, Japan.

An unknown species of the genus Notocotylus (Digenea: Notocotylidae) was found as the larval stage from the lymnaeid snail, Radix auricularia, in a static water area of the Chubetsu River, Hokkaido, the northernmost island of Japan. A DNA barcoding identification system was applied to detect the adult stage. Through the inspection of anatid game birds in Hokkaido, Anas crecca, Anas platyrhynchos, Anas zonorhyncha, and Mareca penelope were demonstrated to serve as the definitive hosts. The detailed morphological features of the species were characterized using adults raised experimentally in immunosuppressed mice and naturally developed larvae in R. auricularia. Although the species is morphologically similar to Notocotylus attenuatus and Notocotylus magniovatus in both adult and larval stages, its taxonomic independence was confirmed by a comprehensive study based on molecular phylogeny, morphology, and ecology. Here we propose Notocotylus ikutai n. sp. for this species. The migratory behavior of the anatid hosts and the North-Eurasian distribution of R. auricularia suggest that the new species is widely distributed in the northern Far East.
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http://dx.doi.org/10.1016/j.parint.2021.102318DOI Listing
August 2021

Severe laryngeal edema caused by Pseudoterranova species: A case report.

Medicine (Baltimore) 2021 Jan;100(4):e24456

Department of Otolaryngology-Head and Neck Surgery.

Rationale: Severe laryngeal edema can cause upper airway obstruction, which is fatal. Pseudoterranova, an uncommon nematode of the family Anisakidae, predominantly invades the stomach after ingestion of the nematodes in raw or undercooked marine fish. There have been a few reports of development of severe laryngeal edema caused by the nematode invading the base of the tongue.

Patient Concerns: A 69-year-old Japanese woman complained of stuffy and scratchy throat for 8 hours and reported eating sashimi, fresh slices of raw jacopever, 4 days before the first visit.

Diagnosis: Endoscopy revealed a white-yellowish wriggling worm at the left side of the base of the tongue and severe edema of the larynx.

Interventions: The worm was extracted using endoscopic forceps. The patient was hospitalized and treated with intravenous injection of an antibiotic and steroid.

Outcomes: The symptoms and laryngeal edema disappeared the next day. The worm was identified as a 4th-stage larva of Pseudoterranova spp based on morphologic features. The serum Anisakis-specific IgE antibody level was high, at 38.6 UA/mL.

Lessons: Clinicians should be aware of the possibility of severe laryngeal edema due to invasion by anisakid nematodes in the pharyngolaryngeal area in cases involving previous ingestion of raw or uncooked marine fish.
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http://dx.doi.org/10.1097/MD.0000000000024456DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7850652PMC
January 2021

Frequent infections of mountain stream fish with the amphibian acanthocephalan, Pseudoacanthocephalus toshimai (Acanthocephala: Echinorhynchidae).

Parasitol Int 2021 Apr 1;81:102262. Epub 2020 Dec 1.

Department of Parasitology, Asahikawa Medical University, Midorigaoka-Higashi 2-1, Asahikawa, Hokkaido 078-8510, Japan.

Pseudoacanthocephalus toshimai is an intestinal acanthocephalan parasite of amphibians in Hokkaido, the northernmost island of Japan. In this study, common freshwater fish of the families Salmonidae and Cottidae in mountain streams around the Kamikawa basin of Hokkaido were examined for acanthocephalan infections with P. toshimai. A total of 160 salmonids and 14 cottids were caught in 4 streams by bait fishing during summer and autumn seasons of 2019. Adult acanthocephalans were found only from the salmonids, namely, Salvelinus leucomaenis leucomaenis, Salvelinus malma krascheninnikovi, Oncorhynchus masou, and Oncorhynchus mykiss. The maximum prevalence reached 58.1% in S. leucomaenis, but the mean worm burden was at low levels (e.g., 3.1 in S. leucomaenis and 2.2 in S. malma). All of the acanthocephalans were identified to P. toshimai by morphological observation and DNA barcoding. Although the male acanthocephalans became sexually mature, the females never reached the gravid adult stage, suggesting that salmonids are unsuitable or aberrant hosts for P. toshimai. The infected fish were found exclusively from a small stream with bush, in which a large habitat of amphibians is included. Ligidium japonicum, a terrestrial isopod, collected from the habitat was highly infected with cystacanth larvae of P. toshimai. The observation of fish stomach contents directly demonstrated that small salmonids eat L. japonicum. The terrestrial isopods, which are washed away by rain into a stream, seem to be a source of salmonid infections with P. toshimai. The habitat of intermediate hosts should be emphasized in the taxonomy of the closely related genera Acanthocephalus and Pseudoacanthocephalus.
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http://dx.doi.org/10.1016/j.parint.2020.102262DOI Listing
April 2021

Brachylaima succini sp. nov. (Trematoda: Brachylaimidae) from Succinea lauta, an amber snail in Hokkaido, Japan.

Parasitol Int 2020 Aug 10;77:102104. Epub 2020 Mar 10.

Faculty of Science, Toho University, Funabashi, Chiba 274-8510, Japan.

Through a continuous survey of trematodes in land snails of Hokkaido, the northernmost island of Japan, we have discovered four species of the genus Brachylaima (Trematode: Brachylaimidae). Among them, Brachylaima ezohelicis, Brachylaima asakawai, and Brachylaima lignieuhadrae have already been described. Each of the three species is a strict specialist in selecting a particular species of land snail as the first intermediate host. In this report, we propose the fourth species, Brachylaima succini sp. nov., based on ecological, morphological, and phylogenetic considerations. Sporocysts and metacercariae of the new species were found exclusively from Succinea lauta, which is known as an amber snail indigenous to Hokkaido. Phylogenetic trees of nuclear 28S rDNA and mitochondrial cytochrome c oxidase subunit 1 (cox1) demonstrated it to be distinct from the other sympatric species. Although metacercariae of the new species possessed unique morphological characters, adult worms experimentally raised from the metacercariae were similar to those of B. ezohelicis and B. lignieuhadrae. Natural definitive hosts of the new species are unknown, but the existence of common cox1 haplotypes from far-distant localities suggests a possibility that birds are involved as the definitive hosts. Findings of amber snails coinfected with both sporocysts of the new species and Leucochloridium perturbatum also support the involvement of birds.
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http://dx.doi.org/10.1016/j.parint.2020.102104DOI Listing
August 2020

Brachylaima lignieuhadrae n. sp. (Trematoda: Brachylaimidae) from land snails of the genus Euhadra in Japan.

Parasitol Int 2020 Feb 12;74:101992. Epub 2019 Sep 12.

Department of Parasitology, Asahikawa Medical University, Asahikawa, Hokkaido 078-8510, Japan.

Land snails of the genus Euhadra (Gastropoda: Bradybaenidae) are indigenous to the Japanese Archipelago. The larvae of an unknown species, tentatively named as Brachylaima sp. B (Trematoda: Brachylaimidae), have been found from Euhadra brandtii sapporo in Hokkaido, the northernmost island of Japan. In this study, a large-scale snail survey covering a wide area of Japan was conducted to confirm the larval parasite from members of Euhadra and related genera. Sporocysts with cercariae were found only from Eu. brandtii sapporo in Hokkaido and Euhadra callizona in central Honshu at low prevalence (1.0-9.6%). The metacercariae were detected widely from 6 species of Euhadra and the related genera at high prevalence (7.1-100%). A molecular identification by DNA barcoding demonstrated almost all of the larvae to be Brachylaima sp. B. Adult worms experimentally raised from the metacercariae were morphologically most similar to Brachylaima ezohelicis in Hokkaido, but could be differentiated by the microstructure of the tegumental surface. We propose Brachylaima lignieuhadrae n. sp. for the unknown species, based on the morphology, DNA profile, host specificity, and geographic distribution. Phylogeography of the new species suggests a possibility that migratory birds serve as the definitive hosts.
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http://dx.doi.org/10.1016/j.parint.2019.101992DOI Listing
February 2020

A Philophthalmid Eyefluke from a Human in Japan.

J Parasitol 2019 08;105(4):619-623

2   Department of Parasitology, Asahikawa Medical University, Asahikawa, Hokkaido 078-8510, Japan.

Philophthalmid eyeflukes are cosmopolitan parasites of birds and occasionally of mammals, including humans. A gravid adult of sp. was found from the bulbar conjunctiva of a 64-yr-old woman in Japan, who was diagnosed with acute conjunctivitis. The parasite was morphologically most similar to , but distinctive in lacking an esophagus and in having clearly lobed testes. The DNA sequence analysis of genes for nuclear ribosomal RNA and mitochondrial cytochrome oxidase subunit 1 supported the identification at generic level. The morphological and molecular analyses strongly suggest that the eyefluke from a human in Japan should be treated as an undescribed species of . The occurrence of human philophthalmosis is very rare. As far as we know, a total of 11 human cases have been reported worldwide to date.
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August 2019

Infection status of commercial fish with cystacanth larvae of the genus Corynosoma (Acanthocephala: Polymorphidae) in Hokkaido, Japan.

Int J Food Microbiol 2019 Sep 21;305:108256. Epub 2019 Jun 21.

Department of Parasitology, Asahikawa Medical University, Asahikawa, Hokkaido 078-8510, Japan.

Acanthocephalans of the genus Corynosoma are known as intestinal parasites, mainly of pinnipeds. Human corynosomiasis has been reported as an infrequent foodborne disease in Hokkaido, the northernmost island of Japan. Potential sources of the human infection are marine fish, because they are paratenic hosts of these parasites. In this study, the prevalence and intensity of larval Corynosoma in commercial fish from 17 fishing ports of Hokkaido were examined from April 2016 to January 2019. Out of a total of 1217 fish examined, 122 (10.0%) were infected with cystacanth larvae. The infected fish assemblage was composed of 7 families and 13 species from all the coastal seas of Hokkaido (the Pacific Ocean, Okhotsk Sea, and Japan Sea), showing that commercial fish can be source of human infection when eaten raw. Flatfish of the family Pleuronectidae showed the highest intensity of cystacanths, ranging from 1 to 56. A DNA barcoding system was developed in this study, based on the standard mitochondrial cox1 sequences of morphologically identified adults of Corynosoma spp. from pinnipeds in Hokkaido. By using the DNA barcoding, most of the fish-derived cystacanths were identified as either C. strumosum or C. villosum, and furthermore, a clinical isolate from human as C. villosum. Both of the species were commonly detected from various fish of Hokkaido, irrespective of the coastal seas. Flatfish frequently harbored C. villosum. Considering the wide range of commercial fish in Hokkaido and the advanced transportation system of fresh fish, there is a possibility that human corynosomiasis will occur everywhere in Japan.
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http://dx.doi.org/10.1016/j.ijfoodmicro.2019.108256DOI Listing
September 2019

Distribution records of three species of Leucochloridium (Trematoda: Leucochloridiidae) in Japan, with comments on their microtaxonomy and ecology.

Parasitol Int 2019 Oct 31;72:101936. Epub 2019 May 31.

School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan.

Insectivorous birds serve as definitive hosts for trematodes of the genus Leucochloridium. The parasites exclusively use amber snails of the family Succineidae as intermediate hosts. A pulsating and colorful display of the larval broodsac in the snail's eyestalk seems to be a caterpillar mimic for attracting birds. A colored design of the broodsac is very useful for parasite identification. In Japan, characteristic broodsacs from amber snails have been recorded from 1980's, but their taxonomic discrimination from Asian, European, and North American species has not been achieved. In this study, old scientific records, sighting information on broodsacs from the general public, and direct molecular evidence by DNA barcoding clearly showed that at least three species of Leucochloridium are distributed in Japan. A vertical-striped broodsac found from Succinea sp. in Okinawa, the subtropical island of Japan, were treated as Leucochloridium sp., but being almost identical to that of Leucochloridium passeri in neighboring Taiwan. The European species of Leucochloridium perturbatum and Leucochloridium paradoxum were frequently detected from Succinea lauta in Hokkaido, the northernmost island of Japan. The former species was common in inland areas of Hokkaido, whereas the latter species was frequently seen in the coastal areas. A possible explanation for the parasite distribution pattern is that principal definitive hosts (migratory or resident birds) differ in each parasite. The conspecificity of Leucochloridium variae in North America and L. perturbatum in Europe and the Far East is also discussed.
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http://dx.doi.org/10.1016/j.parint.2019.101936DOI Listing
October 2019

Description of Enterobius (Colobenterobius) emodensis sp. n. (Nematoda: Oxyuridae) collected from Central Himalayan langur, Semnopithecus schistaceus, in Uttarakhand, India.

Zootaxa 2018 Nov 5;4514(1):65-76. Epub 2018 Nov 5.

Department of Biomedicine / Department of Infectious Disease Control, Faculty of Medicine, Oita University, Hasama, Yufu, Oita 879-5593, Japan..

A new pinworm species, Enterobius (Colobenterobius) emodensis sp. n. (Nematoda: Oxyuridae) is described from the Central Himalayan langur, Semnopithecus schistaceus, in Mandal Valley, Chamoli District, Uttarakhand, India, based on mature and immature adults and fourth-stage larvae. This species closely resembles Enterobius (Colobenterobius) zakiri parasitic in Tarai langur, Semnopithecus hector, recorded from Uttarakhand and Uttar Pradesh, India, but is readily distinguished by having a shorter esophagus and a shorter spicule. It is surmised that this pinworm has co-speciated with the host langur. The new species is also characterized in that the posterior 1/3 of the esophageal corpus is much darker. Phylogenetic analysis based on the sequences of partial Cox1 gene of mtDNA suggested a basal position of diversification of Colobenterobius from the Enterobius lineage.
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http://dx.doi.org/10.11646/zootaxa.4514.1.5DOI Listing
November 2018

A case of small bowel obstruction due to infection with Bolbosoma sp. (Acanthocephala: Polymorphidae).

Parasitol Int 2019 Feb 2;68(1):14-16. Epub 2018 Oct 2.

Department of Infectious Disease Control, Department of Biomedicine, Faculty of Medicine, Oita University, Oita, Japan.

A case of small bowel obstruction caused by Bolbosoma sp. infection is reported. A 27-year-old woman admitted with abdominal pain was diagnosed as small bowel obstruction. Laparoscopic surgery revealed induration in jejunum at ca. 120 cm distal to the ligament of Treiz, attributed to a band connecting the serosa to the ascending mesocolon. Resected band contained an acanthocephalan accompanying foreign body reaction with abscess formation. The parasite belonged to the genus Bolbosoma, of which identification was made by DNA sequence analysis. This is the eighth case of Bolbosoma infection in humans, and the first one causing an ileus.
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http://dx.doi.org/10.1016/j.parint.2018.09.007DOI Listing
February 2019

Brachylaima asakawai sp. nov. (Trematoda: Brachylaimidae), a rodent intestinal fluke in Hokkaido, Japan, with a finding of the first and second intermediate hosts.

Parasitol Int 2018 10 27;67(5):565-574. Epub 2018 Apr 27.

Mie University Graduate School, Faculty of Bioresources, Tsu, Mie 514-8507, Japan.

In the 1970's and 1980's, an unknown species of the genus Brachylaima (Trematoda: Brachylaimidae) had been recorded from the intestines of Rattus norvegicus and Apodemus speciosus in Hokkaido, Japan. The rodent fluke was characteristic in extending a bilateral vitellarium till the level of posterior margin of anterior testis and in keeping almost the same-sized spherical ovary and testes. In this study, the rodent fluke was rediscovered from A. speciosus, Apodemus argenteus, and Myodes rufocanus in Hokkaido. The resultant parasite collection enabled us to make a mitochondrial DNA (mtDNA) barcode for tracking its intermediate hosts. The metacercaria of the rodent fluke was detected frequently from the kidney of three species of land snails (Discus pauper, Succinea lauta, and Ainohelix editha). However, its sporocyst with cercariae was found only from the hepatopancreas of D. pauper, a fairly small snail. The wide-spectrum of the second intermediate host seems to increase the chance of transmitting the parasite to various mammals and birds. The use of indigenous land snails as the first and second intermediate hosts, the distinctiveness of the mtDNA sequence, and the characteristic morphology of all the developmental stages prompted us to propose Brachylaima asakawai sp. nov. for the rodent intestinal fluke in Hokkaido. The present field survey suggests that the life cycle of the new species is primarily dependent on a predator-prey relationship between rodents and D. pauper.
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http://dx.doi.org/10.1016/j.parint.2018.04.010DOI Listing
October 2018

Echinococcus felidis in hippopotamus, South Africa.

Vet Parasitol 2017 Aug 3;243:24-28. Epub 2017 Jun 3.

Immunobiology Research Program, Department of Bacteriology and Immunology, Faculty of Medicine, P.O. Box 21, FI-00014 University of Helsinki, Finland. Electronic address:

Hydatid cysts of Echinococcus felidis are described from the hippopotamus (Hippopotamus amphibius) from Mpumalanga Province, South Africa. Among six hippopotami investigated, hepatic hydatids were found in three. The identification was based on mitochondrial and nuclear DNA sequences. In addition, the rostellar hook morphology was analysed. This is the first morphological description of the metacestode of E. felidis, and the first molecularly confirmed report of the intermediate host of E. felidis in South Africa. The definitive host of E. felidis in South Africa is the lion (Panthera leo).
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http://dx.doi.org/10.1016/j.vetpar.2017.06.001DOI Listing
August 2017

Evolutionary origin of type IV classical cadherins in arthropods.

BMC Evol Biol 2017 06 17;17(1):142. Epub 2017 Jun 17.

Laboratory of Evolutionary Cell and Developmental Biology, JT Biohistory Research Hall, 1-1 Murasaki-cho, Takatsuki, 569-1125, Osaka, Japan.

Background: Classical cadherins are a metazoan-specific family of homophilic cell-cell adhesion molecules that regulate morphogenesis. Type I and type IV cadherins in this family function at adherens junctions in the major epithelial tissues of vertebrates and insects, respectively, but they have distinct, relatively simple domain organizations that are thought to have evolved by independent reductive changes from an ancestral type III cadherin, which is larger than derived paralogs and has a complicated domain organization. Although both type III and type IV cadherins have been identified in hexapods and branchiopods, the process by which the type IV cadherin evolved is still largely unclear.

Results: Through an analysis of arthropod genome sequences, we found that the only classical cadherin encoded in chelicerate genomes was the type III cadherin and that the two type III cadherin genes found in the spider Parasteatoda tepidariorum genome exhibited a complex yet ancestral exon-intron organization in arthropods. Genomic and transcriptomic data from branchiopod, copepod, isopod, amphipod, and decapod crustaceans led us to redefine the type IV cadherin category, which we separated into type IVa and type IVb, which displayed a similar domain organization, except type IVb cadherins have a larger number of extracellular cadherin (EC) domains than do type IVa cadherins (nine versus seven). We also showed that type IVa cadherin genes occurred in the hexapod, branchiopod, and copepod genomes whereas only type IVb cadherin genes were present in malacostracans. Furthermore, comparative characterization of the type IVb cadherins suggested that the presence of two extra EC domains in their N-terminal regions represented primitive characteristics. In addition, we identified an evolutionary loss of two highly conserved cysteine residues among the type IVa cadherins of insects.

Conclusions: We provide a genomic perspective of the evolution of classical cadherins among bilaterians, with a focus on the Arthropoda, and suggest that following the divergence of early arthropods, the precursor of the insect type IV cadherin evolved through stepwise reductive changes from the ancestral type III state. In addition, the complementary distributions of polarized genomic characters related to type IVa/IVb cadherins may have implications for our interpretations of pancrustacean phylogeny.
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http://dx.doi.org/10.1186/s12862-017-0991-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5473995PMC
June 2017

Brachylaima ezohelicis sp. nov. (Trematoda: Brachylaimidae) found from the land snail Ezohelix gainesi, with a note of an unidentified Brachylaima species in Hokkaido, Japan.

Parasitol Int 2017 Jun 25;66(3):240-249. Epub 2017 Jan 25.

School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan.

In the Japanese Archipelago, Ezohelix gainesi, a member of bradybaenid land snails, is endemic mainly to the island of Hokkaido. During July to August of 2016, a survey to detect trematode infections from E. gainesi was carried out at a forest city park in Asahikawa, Hokkaido. Systemic infections of the snails with sporocysts containing short-tailed cercariae were found in 5.3% of 94 individuals examined. Furthermore, most of them (90.4%) harbored non-encysted metacercariae within their kidneys. A DNA sequence identification revealed that both of the sporocyst and the metacercaria belong to an unknown species of the family Brachylaimidae. The metacercariae showed a genetic diversity with 6 haplotypes of mitochondrial DNA (mtDNA) even in the limited sampling area. A definitive host of the unknown species could not be determined, although 34 field mice (Apodemus speciosus) and 21 voles (Myodes rufocanus) from the city park were examined for intestinal parasites. To examine the adult stage, the metacercariae were perorally administrated to mice, together with anti-inflammatory treatment with methylprednisolone. Fully matured adult worms were recovered from the intestinal ileum 8 and 14days postinfection. The gravid adults showed typical features of the genus Brachylaima. A morphological and biogeographical evaluation prompted us to propose Brachylaima ezohelicis sp. nov. for the parasite from E. gainesi. The autochthony of the first intermediate host and the spatial heterogeneity of mtDNA suggest that the new species found in the city park is not a recently expanded population of immigrant origin.
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http://dx.doi.org/10.1016/j.parint.2017.01.015DOI Listing
June 2017

The putative serine protease inhibitor (serpin) genes encoded on Echinococcus multilocularis genome and their expressions in metacestodal stage.

Vet Parasitol 2017 Jan 27;233:20-24. Epub 2016 Nov 27.

Department of Parasitology, Asahikawa Medical University, 2-1-1-1, Midorigaoka-Higashi, Asahikawa, Hokkaido, 078-8510, Japan.

Two putative serpin genes were identified in Echinococcus multilocularis, in addition to the already reported serpinEmu, and were designated as serpin2Emu and serpin3Emu. Western blot analysis using polyclonal antibodies against serpinEmu, putative serpin2Emu protein, and putative serpin3Emu protein indicated that all three proteins were localized in both intracellular and excretory-secretory (ES) fractions of E. multilocularis metacestodes. In addition, immune staining of parasite tissue indicated that all three proteins were localized at the germinal layer.
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http://dx.doi.org/10.1016/j.vetpar.2016.11.019DOI Listing
January 2017

Serological survey of Encephalitozoon cuniculi infection in cats in Japan.

J Vet Med Sci 2016 Nov 20;78(10):1615-1617. Epub 2016 Jun 20.

Laboratory of Veterinary Parasitology, School of Veterinary Medicine, Kitasato University, Towada, Aomori 034-8628, Japan.

Antibodies to Encephalitozoon cuniculi (E. cuniculi) were examined by enzyme-linked immunosorbent assay using E. cuniculi PTP2 recombinant protein from serum samples that had been collected from a total of 295 cats in Japan. Of these samples, 6.1% (18/295) had antibodies against E. cuniculi, which included 6.3% (6/96) of the male cats and 6.0% (12/199) of the female cats. The incidence was slightly higher in feral cats (8.3%, 11/132) compared to domesticated cats (4.3%, 7/163). This suggests the possibility that the cats of our country have become a reservoir of E. cuniculi. This study is the first to demonstrate the prevalence of E. cuniculi infection in cats in Japan.
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http://dx.doi.org/10.1292/jvms.15-0545DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5095633PMC
November 2016

Swine cysticercosis in the Karangasem district of Bali, Indonesia: An evaluation of serological screening methods.

Acta Trop 2016 Nov 29;163:46-53. Epub 2016 Jul 29.

Department of Parasitology, Asahikawa Medical University, Asahikawa, Japan. Electronic address:

A serological assessment was undertaken on pigs from the Kubu and Abang sub-districts of Karangasem on the island of Bali, Indonesia, where earlier studies had detected patients with cysticercosis. Antigens purified from Taenia solium cyst fluid by cation-exchange chromatography were used to evaluate antibody responses in the pigs and the serological tests were also evaluated using sera from pigs experimentally infected with T. solium eggs. A total of 392 serum samples from naturally exposed pigs were tested using an ELISA that could be read based on both a colour change perceptible by the naked eye and an ELISA based on absorbance values. Twenty six (6.6%) pigs were found seropositive by the naked-eye ELISA and were categorized into three groups: strongly positive (absorbance values >0.8, n=6), moderately positive (absorbance values between 0.2 and 0.8, n=7), and weakly positive (absorbance values <0.2, n=13). Necropsies performed on 11 strongly and moderately positive pigs revealed that six strongly positive pigs were infected either solely with T. solium cysticerci (n=3), or co-infected with both T. solium and Taenia hydatigena (n=3). Four moderately positive pigs were infected solely with T. hydatigena. No cysticerci were found in one pig that was moderately positive by the naked-eye ELISA. Two experimentally infected pigs became antibody positive by 6 weeks post-infection, whereas eight control pigs remained negative. An additional 60 pigs slaughtered at authorized abattoirs on Bali were tested using the same ELISA. All 60 pigs were seronegative with no evidence of Taenia infection at necropsy. The results confirm the presence of porcine cysticercosis on Bali and, while the serological responses seen in T. solium infected animals were much stronger than those infected with T. hydatigena, the diagnostic antigens are clearly not species specific. Further studies are necessary to confirm if it is possible to draw a cut off line for differentiation of pig infected with T. solium from those infected with T. hydatigena.
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http://dx.doi.org/10.1016/j.actatropica.2016.07.022DOI Listing
November 2016

Boronic Acid-Appended Molecular Glues for ATP-Responsive Activity Modulation of Enzymes.

J Am Chem Soc 2016 05 19;138(17):5527-30. Epub 2016 Apr 19.

Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.

Water-soluble linear polymers GumBAn (m/n = 18/6, 12/12, and 6/18) with multiple guanidinium ion (Gu(+)) and boronic acid (BA) pendants in their side chains were synthesized as ATP-responsive modulators for enzyme activity. GumBAn polymers strongly bind to the phosphate ion (PO4(-)) and 1,2-diol units of ATP via the Gu(+) and BA pendants, respectively. As only the Gu(+) pendants can be used for proteins, GumBAn is able to modulate the activity of enzymes in response to ATP. As a proof-of-concept study, we demonstrated that trypsin (Trp) can be deactivated by hybridization with GumBAn. However, upon addition of ATP, Trp was liberated to retrieve its hydrolytic activity due to a higher preference of GumBAn toward ATP than Trp. This event occurred in a much lower range of [ATP] than reported examples. Under cellular conditions, the hydrolytic activity of Trp was likewise modulated.
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http://dx.doi.org/10.1021/jacs.6b02664DOI Listing
May 2016

Encephalitozoon infections in Rodentia and Soricomorpha in Japan.

Vet Parasitol 2013 Nov 5;198(1-2):193-6. Epub 2013 Sep 5.

Department of Veterinary Parasitology, School of Veterinary Medicine, Kitasato University, Towada, Aomori 034-8628, Japan.

Encephalitozoon is an obligate intracellular microsporidian parasite that infects a wide range of mammalian hosts. In this study, we used nested PCR to investigate the presence of Encephalitozoon infection in Rodentia and Soricomorpha in Japan. We attempted to amplify and sequence Encephalitozoon-specific DNA from brain and viscera samples of 180 animals collected between 2008 and 2010. Forty-three samples (23.9%) from the orders Rodentia and Soricomorpha were positive for Encephalitozoon. This study is the first report of Encephalitozoon infection in Rodentia and Soricomorpha in Japan, and our findings suggest that these hosts may play a role in the spread of microsporidian spores in the environment.
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http://dx.doi.org/10.1016/j.vetpar.2013.08.018DOI Listing
November 2013

Effect of sex steroids on Babesia microti infection in mice.

Am J Trop Med Hyg 2013 Feb 18;88(2):367-75. Epub 2012 Dec 18.

Department of Veterinary Parasitology, School of Veterinary Medicine, Kitasato University, Towada, Aomori, Japan.

Sex-based-differences are known to affect susceptibility to protozoan infections, but their effects on parasitemia and clinical symptoms in Babesia infections remain unclear. We examined the sex-based susceptibility of various mouse strains to Babesia microti Munich strain infection. In all strains, male mice exhibited significantly higher peak parasitemia and more severe anemia than female mice. Testosterone and estradiol-17β treatment caused an increase in parasitemia and aggravation of anemia. Orchidectomized male mice receiving testosterone exhibited smaller splenic macrophage populations three days after infection, smaller B cell populations 10 days after infection, and reduced splenic tumor necrosis factor-α and interferon-γ mRNA expression than mice that did not receive testosterone. Mice receiving estradiol-17β did not exhibit immunosuppressive effects. Thus, a weakened and delayed innate immunity response may lead to acquired immunity failure. The results suggested that testosterone directly affects T or B cells, leading to delayed acquired immunity, dramatically increased parasitemia, and severe anemia.
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http://dx.doi.org/10.4269/ajtmh.2012.12-0338DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3583332PMC
February 2013

Downregulation of hepatic cytochrome P450 3A in mice infected with Babesia microti.

J Vet Med Sci 2012 Feb 29;74(2):241-5. Epub 2011 Sep 29.

Department of Veterinary Teaching Hospital, School of Veterinary Medicine, Kitasato University, Towada, Aomori 034–8628, Japan.

To investigate effects of Babesia infection on drug metabolism, we intraperitoneally inoculated B. microti into ICR mice and measured the expression and activity of hepatic cytochrome P450 (CYP) 3A, a major drug-metabolizing enzyme. Twelve days after infection, CYP3A11 mRNA, CYP3A protein and activity and mRNAs of nuclear receptors, which participate in CYP3A expression, were significantly reduced. These results suggest that B. microti infection suppresses CYP3A-dependent drug metabolism. Additionally, tumor necrosis factor (TNF)-α and nitric oxide synthase (NOS) 2 mRNAs were induced in the infected mouse liver. Since TNF-α is one of the potent mediators that induce NOS2 and repress CYP3A transcription, the possible involvement of TNF-α in this downregulation of CYP3A was discussed.
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http://dx.doi.org/10.1292/jvms.11-0036DOI Listing
February 2012

A PCR-based epidemiological survey of Hepatozoon canis in dogs in Nigeria.

J Vet Med Sci 2008 Jul;70(7):743-5

Department of Veterinary Parasitology, School of Veterinary Medicine, Kitasato University, Towada, Aomori, Japan.

The prevalence of Hepatozoon canis infections in dogs in Nigeria was surveyed using molecular methods. DNA was extracted from blood samples obtained from 400 dogs. A primer set that amplified the Babesia canis 18S rRNA gene, which has high similarity to the H. canis 18S rRNA gene, was used for the PCR. As a result, samples from 81 dogs (20.3%) produced 757 bp bands, which differed from the 698 bp band that corresponded to B. canis infection. The sequence of the PCR products of 10 samples were determined, all of which corresponded with the H. canis sequence.
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http://dx.doi.org/10.1292/jvms.70.743DOI Listing
July 2008

Molecular survey of Babesia canis in dogs in Nigeria.

J Vet Med Sci 2007 Nov;69(11):1191-3

Department of Veterinary Parasitology, School of Veterinary Medicine, Kitasato University, Towada, Aomori 034-8628, Japan.

An epidemiological study of Babesia canis in dogs in Nigeria was performed. Four hundred blood samples collected from dogs in Nigeria were investigated using nested PCR and sequence analysis. On nested PCR screening, nine samples (2.3%) produced a band corresponding to a 698-bp fragment indicative of B. canis infection. Sequence analysis of the PCR products identified eight samples (2.0%) as B. canis rossi and the ninth (0.3%) as B. canis vogeli. This is the first report of the prevalence of B. canis rossi and B. canis vogeli in dogs in Nigeria.
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http://dx.doi.org/10.1292/jvms.69.1191DOI Listing
November 2007

Molecular evidence of Babesia equi transmission in Haemaphysalis longicornis.

Am J Trop Med Hyg 2007 Apr;76(4):694-7

Department of Veterinary Parasitology, School of Veterinary Medicine and Animal Sciences, Kitasato University, Towada, Aomori, Japan.

We studied the tick, Haemaphysalis longicornis, to determine the possibility of both transovarial and transstadial transmission of Babesia equi. We also studied the usefulness of the needle injection method for pathogenic tick-transmitted organisms including Babesia parasites. Erythrocytes infected with B. equi were injected into the midgut of engorged adults or nymphs using a hypodermic needle passed through the integument. DNA of B. equi in ticks was detected using nested polymerase chain reaction (PCR). B. equi DNA was present in adults, eggs, and larvae, indicating that transovarial transmission occurred. B. equi DNA was present in adults that developed from infected nymphs, and the B. equi antigen was present in their salivary glands, indicating that transstadial transmission occurred. These findings suggest that H. longicornis may play a role in the transmission of B. equi.
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April 2007

Molecular cloning and partial characterization of Babesia equi EMA-3.

Mol Biochem Parasitol 2006 Dec 1;150(2):371-3. Epub 2006 Sep 1.

Department of Veterinary Parasitology, School of Veterinary Medicine and Animal Sciences, Kitasato University, Towada, Aomori 034-8628, Japan.

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http://dx.doi.org/10.1016/j.molbiopara.2006.08.004DOI Listing
December 2006
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