Ovarian nests in cultured Russian sturgeon Acipenser gueldenstaedtii and North American paddlefish Polyodon spathula comprised of previtellogenic oocytes

Abstract

Ovarian nests in the ovaries of sexually maturing Russian sturgeon Acipenser gueldenstaedtii and North American paddlefish Polyodon spathula were investigated. They comprised early previtellogenic, diplotene stage oocytes and somatic cells. In the nucleoplasm, these oocytes contained chromatin in the form of grains, threads and lampbrush chromosomes, primary nucleoli and multiple nucleoli. Two stages of oocytes in nests were distinguished by differences in the distribution of mitochondria with distorted cristae and lipid droplets in the ooplasm. These stages were as follows: pre-early stage 1 (PE 1) and early stage 1 (EP 1) previtellogenic oocytes. In PE 1 oocytes few mitochondria with distorted cristae and lipid droplets were distributed randomly. The ooplasm of PE 1 oocytes was not differentiated into homogeneous and granular compartments. In EP 1 oocytes, mitochondria with distorted cristae were more numerous and grouped in the vicinity of the nucleus, lipid droplets accumulated near these mitochondria. In the nucleoplasm of EP 1 oocytes several low electron-dense spherical bodies, possibly Cajal bodies, were present.

Interspecific hybridization of sturgeon species affects differently their gonadal development

“…Previtellogenic oocytes and both previtellogenic and vitellogenic oocytes in ovarian follicles, as seen in the present study, were already described in Russian sturgeon (Zelazowska et al 2015) and in Siberian sturgeon (Zelazowska and Fopp-Bayat 2017).…”

Previtellogenic oocytes of South African largemouth bass Micropterus salmoides Lacépède 1802 (Actinopterygii, Perciformes) ‐ the Balbiani body, cortical alveoli and developing eggshell

“…In the latter species, numerous nucleoli arise due to the extrachromosomal amplification of cistrons of ribosomal deoxyribonucleic acid (rDNA) which takes place in nucleoplasm during the pachytene stage (Thiry & Poncin, 2005). This process has also been described in the nucleoplasm of oocytes of other vertebrates including sturgeons and paddlefish, and amphibians (Coimbra & Azevedo, 1984;Raikova, 1976;Raikova, Steinert, & Thomas, 1979;Żelazowska & Fopp-Bayat, 2017b;Żelazowska et al, 2015). Such multiplied nucleoli synthetize ribosomes subunits that are then transported to the ooplasm and are stored until the cleavage in embryogenesis.…”

“…It has also been investigated in teleost fish, for example, in zebrafish Danio rerio (Elkouby, ; Elkouby et al, ; Elkouby & Mullins, ; Lyman‐Gingerich & Pelegri, ; Marlow & Mullins, ), rainbow trout Salmo gairdneri (Beams & Kessel, ), golden grey mullet Mugil (Liza) auratus (Bruslé, ), medaka Oryzias latipes (Iwamatsu & Nakashima, ; Kobayashi & Iwamatsu, ; Nakamura et al, ), and in the Atlantic salmon Salmo salar (Škugor, Tveiten, Johnsen, & Andersen, ). It is also present in oocytes of several species of sturgeons and paddlefish (Chondrostei, Acipenseriformes); for example, in the Russian sturgeon, Acipenser gueldenstaedtii (Zelazowska et al, ; Żelazowska, Jankowska, Plewniak, & Rajek, ), Siberian sturgeon, A. baerii (Żelazowska & Fopp‐Bayat, , ), Chinese, A. sinensis , Dabry's, A. dabryanus sturgeons (Yang, Yue, Ye, Li, & Wei, ; Ye et al, ; Ye, Li, Yue, Yang, & Wei, ; Ye, Yue, Yang, Li, & Wei, ; Yue et al, ), the North American paddlefish, Polyodon spathula (Żelazowska et al, ; Żelazowska & Kilarski, ) as well as in numerous species of invertebrates (e.g., Bilinski et al, ; Kloc, Jedrzejowska, Tworzydlo, & Bilinski, ). In all species investigated, the Balbiani body is involved in the development of ooplasm polarity and marks the future vegetal region or vegetal pole in the oocytes.…”

Previtellogenic and vitellogenic oocytes in ovarian follicles of cultured siberian sturgeon Acipenser baerii (Chondrostei, Acipenseriformes)

“…In nuclei in previtellogenic oocytes of cultured A. gueldenstaedtii and of P. spathula , these multiple nucleoli are transcriptionally active, i.e., have well‐developed fibrillar and granular components. They are more or less spherical and locate close to the nuclear envelope (Żelazowska et al, ). In previtellogenic oocytes of A. baerii , nucleoli locate also near the nuclear envelope (Le Menn and Pelissero, ).…”

“…Females reared under controlled conditions grow and reach maturity faster than in the wild (Billard and Lecointre, ). In cultured fish, several abnormalities sometimes occur during gonadogenesis and gametogenesis (Williot and Brun, ; Rzepkowska and Ostaszewska, ; Rzepkowska et al, ; Żelazowska et al, ).…”