Spermiogenesis and spermatozoon ultrastructure of the bothriocephalidean cestode Clestobothrium crassiceps (Rudolphi, 1819), a parasite of the teleost fish Merluccius merluccius (Gadiformes: Merlucciidae)

Spermiogenesis and the ultrastructure of the spermatozoon of the bothriocephalidean cestode Clestobothrium crassiceps (Rudolphi, 1819), a parasite of the teleost fish Merluccius merluccius (Linnaeus, 1758), have been studied by means of transmission electron microscopy. Spermiogenesis involves firstly the formation of a differentiation zone. It is characterized by the presence of two centrioles associated with striated rootlets, an intercentriolar body and an electron-dense material in the apical region of this zone. Later, two flagella develop from the centrioles, growing orthogonally in relation to the median cytoplasmic process. Flagella then undergo a rotation of 90° until they become parallel to the median cytoplasmic process, followed by the proximodistal fusion of the flagella with the median cytoplasmic process. The nucleus elongates and afterwards it migrates along the spermatid body. Spermiogenesis finishes with the appearance of the apical cone surrounded by the single helical crested body at the base of the spermatid. Finally, the narrowing of the ring of arched membranes detaches the fully formed spermatozoon. The mature spermatozoon of C. crassiceps is filiform and contains two axonemes of the 9 + '1' trepaxonematan pattern, a parallel nucleus, parallel cortical microtubules, and electron-dense granules of glycogen. The anterior extremity of the gamete exhibits a short electron-dense apical cone and one crested body, which turns once around the sperm cell. The first axoneme is surrounded by a ring of thick cortical microtubules that persist until the appearance of the second axoneme. Later, these thick cortical microtubules disappear and thus, the mature spermatozoon exhibits two bundles of thin cortical microtubules. The posterior extremity of the male gamete presents only the nucleus. Results are discussed and compared particularly with the available ultrastructural data on the former 'pseudophyllideans'. Two differences can be established between spermatozoa of Bothriocephalidea and Diphyllobothriidea, the type of spermatozoon (II vs I) and the presence/absence of the ring of cortical microtubules.

Sääty-yhteiskunnan kirjastosta kansalaisyhteiskunnan kirjastoksi : yleisten kirjastojemme murroskausi 1890-luvulta 1920-luvulle

Summary: From a society of estates to a society of citizens : Finnish public libraries become American

Spermiogenesis and spermatozoon ultrastructure of the bothriocephalidean cestode Clestobothrium crassiceps (Rudolphi, 1819), a parasite of the teleost fish Merluccius merluccius (Gadiformes: Merlucciidae)

Spermiogenesis and the ultrastructure of the spermatozoon of the bothriocephalidean cestode Clestobothrium crassiceps (Rudolphi, 1819), a parasite of the teleost fish Merluccius merluccius (Linnaeus, 1758), have been studied by means of transmission electron microscopy. Spermiogenesis involves firstly the formation of a differentiation zone. It is characterized by the presence of two centrioles associated with striated rootlets, an intercentriolar body and an electron-dense material in the apical region of this zone. Later, two flagella develop from the centrioles, growing orthogonally in relation to the median cytoplasmic process. Flagella then undergo a rotation of 90° until they become parallel to the median cytoplasmic process, followed by the proximodistal fusion of the flagella with the median cytoplasmic process. The nucleus elongates and afterwards it migrates along the spermatid body. Spermiogenesis finishes with the appearance of the apical cone surrounded by the single helical crested body at the base of the spermatid. Finally, the narrowing of the ring of arched membranes detaches the fully formed spermatozoon. The mature spermatozoon of C. crassiceps is filiform and contains two axonemes of the 9 + '1' trepaxonematan pattern, a parallel nucleus, parallel cortical microtubules, and electron-dense granules of glycogen. The anterior extremity of the gamete exhibits a short electron-dense apical cone and one crested body, which turns once around the sperm cell. The first axoneme is surrounded by a ring of thick cortical microtubules that persist until the appearance of the second axoneme. Later, these thick cortical microtubules disappear and thus, the mature spermatozoon exhibits two bundles of thin cortical microtubules. The posterior extremity of the male gamete presents only the nucleus. Results are discussed and compared particularly with the available ultrastructural data on the former 'pseudophyllideans'. Two differences can be established between spermatozoa of Bothriocephalidea and Diphyllobothriidea, the type of spermatozoon (II vs I) and the presence/absence of the ring of cortical microtubules.

First report of the Iowa Soldiers' Monument 1890; Biennial report of the Iowa Soldiers and Sailors Monument Commission, 1894-95

This contains the first (1890),second(1892-93)and third (1894-95) biennial reports of the Iowa Soldiers and Sailors Monument Commission.

[Lettres du directeur des Beaux-Arts, Gustave Larroumet, au directeur du théâtre national de l'Opéra [Ritt ou Gailhard], 30 janvier et 4 février 1890]

A propos de la mise à disposition de l'Opéra pour la représentation de retraite de l'acteur Dumaine

[7 lettres autographes signées de Jules Barbier à Henri Heugel, 1890]

23 janvier 1890. Lui donne carte blanche pour agir auprès de Michaëlis et lui racheter son reste d'exploitation. - 27 février 1890. Au sujet des droits de "Mignon" et "Hamlet" : "je voudrais bien ne pas perdre des droits assez importants actuellement en friche". - 16 mars 1890. Lui demande quelles sont les conditions de Mlle Arnoldson. - 7 avril 1890. Regrette de ne pouvoir répondre à son aimable invitation. - 20 mai 1890. Au sujet de son poème "Circé" rejeté par Léo Delibes : "Je vois venir le moment où je ne pourrai plus placer un poème d'opéra". - 2 juin 1890. Souhaite obtenir des éclaircissements au sujet de sa condamnation à payer une amende de 200 francs pour la publication de "Fleur de neige" sans la restriction accoutumée. - 19 juillet 1890. Au sujet de son poème de "Circé" qu'il souhaite mettre à disposition de Heugel