Конференции Карельского научного центра РАН, XIII Международный Нематологический симпозиум «Нематоды и другие Ecdysozoa в изменяющейся среде обитания»

Размер шрифта: 
Male gametes in the Ecdysozoan worms: Everything's Alright!
Vladimir V. Yushin, L. A. Gliznutsa, E. A. Sokolova, J. K. Zograf

Изменена: 2019-04-30

Аннотация


The metazoan clade Ecdysozoa indicates the close relationships between the moulting invertebrate phyla where worm-like aschelminth taxa Nematoda, Nematomorpha, Kinorhyncha, Loricifera and Priapulida are phylogenetically distant from the arthropod related phyla. Relationships of worm-like ecdysozoan here discussed using male gamete morphology as the character reflecting their phylogeny. Primitive spermatozoa with a rounded head, an acrosome, a nucleus with a nuclear envelope, mitochondria and a flagellum were found in the most primitive ecdysozoan worms, Priapulida. Flagellate elongated modified spermatozoa were found in the interstitial priapulids and Loricifera. The spermatozoa of Kinorhyncha have well developed axoneme but unusual ultrastructural features. Data on spermatozoa do not contradict the traditional association of Priapulida, Loricifera and Kinorhyncha as the supertaxon Scalidophora. Aflagellate aberrant spermatozoa are characterised by absence of an axoneme, an acrosome and a nuclear envelope; they usually include multiple mitochondria and unique membranous components. These features were well demonstrated in Nematomorpha and Nematoda. Spermatozoа of nematomorphs are rod-shaped cells with an expanded anterior “acrosomal complex” and a posterior part with axial cylindrical nucleus surrounded by layers of cisterns. There is no axoneme but usual mitochondria occur in the acrosomal complex. The aberrant nematode spermatozoa have no axoneme and acrosome being bipolar cells with anterior pseudopod and cell body which includes nucleus without a nuclear envelope, mitochondria and membranous organelles. Analysis of the newest original data on the sperm development in the kinorhynchs, nematomorph Gordionus alpestris and several free-living nematodes of the class Enoplea supports association of Nematoda and Nematomorpha as the supertaxon Nematoida. (Support: RFBR 17-04-00719; RFBR 18-04-00256).