魚病研究
Online ISSN : 1881-7335
Print ISSN : 0388-788X
ISSN-L : 0388-788X
50 巻, 4 号
選択された号の論文の5件中1~5を表示しています
論文
  • Kazuo Ogawa, Kousuke Akiyama, Daniel Grabner
    2015 年 50 巻 4 号 p. 183-191
    発行日: 2015年
    公開日: 2015/12/29
    ジャーナル フリー
    Paradeontacylix buri n. sp. is described based on specimens from the afferent branchial arteries of the Japanese amberjack Seriola quinqueradiata cultured in Mie and Oita Prefectures, Japan. The new species can be differentiated from congeners by a body of up to 4.15 mm with lanceolate tegumental spines of the same size throughout the body, uterus ascending after leaving the oötype and the vitellarium not extending posterior to the ovary. P. buri n. sp. is unique among Paradeontacylix species from Seriola spp. in having the same size tegumental spines throughout the body. A phylogenetic analysis based on the sequences of the internal transcribed spacer 2 and on the 28S rRNA-gene demonstrated that P. buri is grouped with other Paradeontacylix species from Seriola spp., indicating that the enlarged tegumental spines in the posteriormost rows in the other Paradeontacylix spp. from Seriola spp. are not a morphological feature at the generic level. Another blood fluke, Paradeontacylix sp., is described based on a single specimen from the afferent branchial artery of yellowtail amberjack S. lalandi cultured in Oita Prefecture, Japan. This species may be differentiated from the most similar P. buri n. sp. by the cirrus (conical and thick walled in Paradeontacylix sp. vs. spherical and thin-walled in P. buri) and by the uterus (extending posteriorly up to the level of the oötype vs. extending posterior to the oötype).
  • Chuandeng Tu, Koushirou Suga, Kinya Kanai
    2015 年 50 巻 4 号 p. 192-199
    発行日: 2015年
    公開日: 2015/12/29
    ジャーナル フリー
    Streptococcus parauberis is a pathogen of streptococcosis in turbot Scophthalmus maximus and the Japanese flounder Paralichthys olivaceus. S. parauberis isolates from diseased Japanese flounder have been classified into several serological phenotypes. In this study we analyzed the DNA sequence of the genetic locus for capsular polysaccharide (CPS) biosynthesis of S. parauberis KRS02083 (subserotype Ia), NUF1003 (subserotype Ib), NUF1071 (subserotype Ic), NUF1032 (serotype II), 2007-1 (nontypeable/PFGE cluster I) and NUF1095 (nontypeable/PFGE cluster III) to elucidate the genetic basis for serological diversity. As a result, three kinds of cps locus were revealed among serotypes and subserotypes, namely the loci for subserotype Ia, subserotypes Ib/Ic and serotype II. The genetic structure of cps loci suggests that the capsules of S. parauberis are synthesized through the Wzy-dependent pathway. Subserotypes Ib and Ic possessed the same genetic structure, although single-base substitution at several regions or insertion of an IS (insertion sequence) element was found in subserotype Ic. The nontypeable strains, which agglutinated with both serotypes I and II antisera, possessed the same genetic structure as subserotype Ib/Ic or serotype II with single-base substitution at several regions.
  • 福田 穣, 津江 佑哉, 追中 大作, 和田 善信, 山下 亜純, 浦崎 慎太郎, 吉岡 宗祐, 木本 圭輔, 吉田 照
    2015 年 50 巻 4 号 p. 200-206
    発行日: 2015年
    公開日: 2015/12/29
    ジャーナル フリー
     2012年以降,診断用の抗KG型ウサギ血清に凝集しないLactococcus garvieae(非凝集性株)が,養殖場のブリとカンパチ病魚から分離されている。これら魚種への非凝集性株の病原性が感染実験で確認された。そこで,抗KG型血清凝集株(従来型株)および非凝集性株のホルマリン不活化菌体(FKC)でブリを免疫し,交差防御効果を検討した。その結果,両免疫原は共に同型株の攻撃に対して高い予防効果を示したものの,従来型株FKCによる免疫は非凝集性株に対して効果が不十分であり,非凝集性株FKCによる免疫は従来型株に対して全く効果を示さなかった。非凝集性株は,日本の海産魚類における新しい血清型の病原性L. garvieaeである。
  • Indah Istiqomah, Yasuhiko Kawato, Mahmoud Mostafa Mahmoud, Jun Okuda, ...
    2015 年 50 巻 4 号 p. 207-212
    発行日: 2015年
    公開日: 2015/12/29
    ジャーナル フリー
    Edwardsiella tarda causes a serious disease known as edwardsiellosis in farmed freshwater and marine fishes. We previously reported that the hemagglutination and cell adherence activities of E. tarda increase in high-salt culture conditions (3% NaCl). This paper describes the induction of fimbriae expression in E. tarda in such high-salt (3% NaCl) culture conditions, using two different phenotypic strains of E. tarda, FK1051 (motile) and MEE0309 (non-motile), isolated from diseased fish. Both strains exhibited faster growth in liquid medium supplemented with 0% to 2% NaCl and slower growth in the 3% NaCl conditions. Hemagglutination activity against guinea pig erythrocytes was detected only in the 2% NaCl and/or 3% NaCl cultures. Electron microscopy revealed two types of fimbriae. The first type was thick (ca. 9 nm) and appeared only in the 0% NaCl culture of FK1051, and the second type was thin (ca. 4 nm) and appeared in the 3% cultures of both strains. The expressions of the major fimbrial subunit gene (etfA) in both strains were significantly higher in the 3% NaCl cultures than in the 0% NaCl cultures. The present results suggest that the thin type of fimbriae is involved in the cell adherence of E. tarda.
短報
  • Chuandeng Tu, Koushirou Suga, Kinya Kanai
    2015 年 50 巻 4 号 p. 213-215
    発行日: 2015年
    公開日: 2015/12/29
    ジャーナル フリー
    A multiplex PCR assay for differentiation of Streptococcus parauberis serotypes was developed. The three primer pairs for subserotypes Ia and Ib/Ic and serotype II were designed from the serotype-specific sequences of the wzy gene in the loci for capsular polysaccharide biosynthesis. All of 188 S. parauberis isolates from Japanese flounder showed positive reaction with the expected size of PCR product for each serotype, which was consistent with the results of agglutination test using rabbit antisera. The nontypeable isolates, which are not differentiated by agglutination test, could be identified as subserotype Ib/Ic or serotype II. Other streptococci including S. parauberis derived from cow and major bacterial fish pathogens showed negative reaction.
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