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アイテム
アコヤガイに寄生する吸虫の生活史ならびにその病害について
https://fra.repo.nii.ac.jp/records/2009054
https://fra.repo.nii.ac.jp/records/2009054161aa254-87d4-4062-b6d7-3b5c8eb517fb
| Item type | 紀要論文 / Departmental Bulletin Paper(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2024-06-27 | |||||
| タイトル | ||||||
| タイトル | アコヤガイに寄生する吸虫の生活史ならびにその病害について | |||||
| 言語 | ja | |||||
| タイトル | ||||||
| タイトル | Studies on the life-history of the trematode parasitic in pearl oyster, Pinctada fucata, and en the hindrance for pearl culture | |||||
| 言語 | en | |||||
| 言語 | ||||||
| 言語 | jpn | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_6501 | |||||
| 資源タイプ | departmental bulletin paper | |||||
| アクセス権 | ||||||
| アクセス権 | metadata only access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||
| 著者 |
阪口, 清次
× 阪口, 清次 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | The results obtained from the present studies are summarized as follows: I. The life-history of the trematoda, Bucephalus varicus. (1) The biology of the sporocyst and cercaria in the first intermediate host, the pearl oyster. 1) The very young sporocysts are spherical and 20-30μ in diameter. They grow into a cylindrical bodies with one or more branches, in which spherical germ-cell arise and each of which develops by nucleare division into a germ-ball measuring of 22μ in diameter. Soon after, the germ-ball begins to elongate when it has reached to 50-60μ long, a pair of rudimental tails becomes discernible at the posterior end of its body. When the larval cercaria comes up to about 80μ in length, a pharynx and rhynchus are formed, viz .- the former on posterio-ventral suface of the midbody, and the later at the anterior extremity of the body. When it is about 100μ in length, the excretory vesicle can be seen. Thus, reaching to about 180μ in length, it is completed in morphogenesis. 2) In the Ago Bay situated north of Kisyu province, the germ-balls in mature sporocyst which are found in the pearl oyster in July becomes young cercariae in August. From September to November the youngs grow larger and soon leave the host. However, the sporocysts remain in the body of pearl oyster as they are and pass the winter, and the formation of cercariae begins with the rise of water temperature in the following year. While in the southern warmer regions, the formation of cercariae in the sporocyst begins 1 or 2 months early according to earlier rise of water temperature. 3) The living cercaria which emerged from the first intermediate host is elongate and is cover with minute scales. The body is 163-273μ in length and 45-60μ in breadth in fixed specimens. Mouth is situated on the posterio-ventral surface of the midbody and it is communicating with a simple sac-like intestine. The excretory vesicle extends from near the posterior end of the body to about the middle level of the pharynx. The rhynchus formed by a mass of gland cells is terminating to four lips, each with a pointed tip. 4) Within the temperatures of 10-30˚C, the young cercaria in the sporocyst parasitizing in pearl oyster is fast in growth at higher temperature. The cercaria which emerged from the host into the water keeps on an uninterrupted movement, ascending or decending by the extension and contraction of the tails. The life of free cercariae in water are about 3 days at 25˚C, but they are having the power to penetrate into the second intermediate host within 24 hours, of course, the power is strong just after emergence. (II) The biology of the metacercaria obtained from the second intermediate host. 1) Several species of fish expected to be the second intermediate host of this trematoda were tested to infect with the cercariae obtained from pearl oyster. The metacercariae were obtained successfully from the fishes experimented. The metacercaria forcibly induced from the cyst is elongate and coverd with minute spines. The body is 230-312μ in length and 84-140μ in breadth in fixed specimens. 2) The morphology of the metacercaria were observed carefully and compared with other species belonging to the genus Bucephalus. The morpholgical observation proved that the metacercaria is resembling to Bucephalus varicus Manter, 1940. 3) The naturally infected metacercariae were found in the fins and muscular tissue of the small fishes, Atherina bleekeri, Spratelloides japonicus and Engraulis japonica, collected in pearl farms, where the pearl oysters infected with the cercaria were prevalent. The infection rate with this metacercaria in Atherina bleekeri, is related to the maturing and emerging season of the cercaria in the first intermediate host. (III) The biology of trematoda (adult form) on the final host. 1) Many kinds of fish living in pearl oyster farm, where the pearl oysters heavily infected with the cercaria are found, were collected and examined in order to determine the final host of this trematoda belonging to the genus Bucephlus. A species of trematoda was found in the digestive organs of Caranx sexfasciatus and C. ignobilis, and the species was identifed with Bucephalus varicus Manter 1940. The species bears characteristics of the metacercaria which could be found in the body of some other small fishes or in the artificially infected fishes with the cercaria. The trematoda was frequently found in the carangid fish caught in pearl oyster farms, where the cercaria infection among pearl oysters are severe, while the trematoda was not found always in the fish obtained from the farms free from the cercaria infection. The infection season in which carangid fish heavily infect with this trematoda is closely related to the maturing season of the cercariae, especially to the time when they are leaving the pearl oyster. 2) Expecting the carangid fishes, Caranx sexfasciatus and C. equula, to be the final host of this trematoda, they were fed with the encysted metacercariae grown up in the body of Rudarius ercodes, by artificial infection with the cercaria parasitic in the pearl oyster. The adult flukes developed from the metacercariae were obtained from the experimented fishes. The metacercariae emerge from their cysts in the stomach of the fish, then they migrate to the intestine and 7 days after, most of them are found in the intestine. The juvenile flukes live in the intestine during some periods, after that, they migrate into the pyloric caecum and within 2-3 weeks after infection, they become adult form and reach 1925 ± 117μ (n=22) in average length. The fluke obtained from the artificial infection was identified with Bucephalus varicus Manter. II. The specific name of this trematoda. Judging from the above-mentioned results, it is clear that the cercaria parasitic in the pearl oyster, which has been described as Bucephalus margaritae Ozaki et Ishibashi, is young form B. varicus and the carangid fishes, Caranx sexfasciatus, C. equula and C. ignobilis to be the final hosts of this cercaria. III. Injuries caused by the trematoda. 1) Discrimination of the infected pearl oyster. Although advanced stages of infection are easily recognized by the yellow network of trematode sporocysts which are occuring in the most of the organs of pearl oyster, but the early stages of infection can be distinguished from uninfected pearl oyster only by the detection of the presence of young sporocysts in the tissue with microscopy. Those young sporocysts grow larger and become to penetrat all tissues of the pearl oyster. In such stages, the infected pearl oysters are distinguished from the uninfected by the findings of the efferrent branchial veins which in the uninfected are colorless and transparent, but in the infected are corpulent and light yellow. 2) Physiological conditions of the infected pearl oyster. The physiological conditions of pearl oysters as measued by the ratio of adductor muscle weight to shell weight showed wide annual changes, the ratio decreasing remarkably during the period of September to October when the cercariae mature and leave them. 3) Qualities of the pearls produced by infected pearl oyster. The pearl oyster suffering the advanced stages of infection showed a high mortarity after operation when they are used as mother-shells. The pearls of low qualities such as 'kizudama" (spotted pearls), "usumakidama" (pearl with thin pearl layers) are produced in high ratio in those oysters. In addition, they are useless for the so-called "piece-shell", because "usumakidama" are produced frequently when their mantle pieces are transplanted. In view of these respects, it is considered that the infected pearl oysters should not be used as mother-shell as well as piece-shell. The pearl oysters infected during the autumn of the preceding years do not show any decreases of their activities before summer. Therefore it seems to be a possibility that they can be used successfully as piece-shell until summer. | |||||
| 言語 | en | |||||
| 書誌情報 |
ja : 国立真珠研究所報告 en : Bulletin of the National Pearl Research Laboratory 巻 13, p. 1635-1688, ページ数 54, 発行日 1968-07-05 |
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| 出版者 | ||||||
| 出版者 | 国立真珠研究所 | |||||
| 言語 | ja | |||||
| 出版者 | ||||||
| 出版者 | National Pearl Research Laboratory | |||||
| 言語 | en | |||||
| 書誌レコードID | ||||||
| 収録物識別子タイプ | NCID | |||||
| 収録物識別子 | AN00091717 | |||||
| 情報源 | ||||||
| 識別子タイプ | Local | |||||
| 関連識別子 | pearl_k_1635 | |||||
| 関連サイト | ||||||
| 識別子タイプ | URI | |||||
| 関連識別子 | https://jp-pearl.com/wp-content/uploads/2018/06/houkoku013.pdf#007 | |||||
| 言語 | ja | |||||
| 関連名称 | 日本真珠振興会Archive | |||||
