TY - JOUR

T1 - Spermatogenesis and lobular cyst type of testes organization in marine gastropod Littorina saxatilis (Olivi 1792)

AU - Demin, Sergei Iu

AU - Stefanova, Vera N.

AU - Granovitch, Andrey I.

AU - Mikhailova, Natalia A.

PY - 2019/6

Y1 - 2019/6

N2 - Although individual stages of spermatogenesis in Littorina saxatilis are well studied at the electron microscopic level, the gonad structure and the spatial localization of gametes at different stages of maturation remain unclear. Using differential-interference contrast (DIC) for observations of fresh tissue we show that the mature testis consists of numerous ovoid lobules forming larger lobes. The lobules of intact mature testes of L. saxatilis are filled with randomly arranged multicellular cysts containing gametes at different stages of maturation. Gametes within a cyst are highly synchronized in respect of the differentiation degree. At the same time, no spatial gradient in the arrangement of cysts according to the maturation degree of gametes in them was observed in any of the studied lobules. The male gonads contain cysts with early spermatids, mid, late spermatids, and spermatozoa. Using silver-staining, DAPI, and chromomycin A3 (CMA3) staining, we identify 20 main types of nucleus organization in differentiating sperm. Premature and mature male gonads contain cysts with a mosaic arrangement as well as rare solitary cyst cells, goniablast cysts, or separate spermatogonia in between them. Our data indicate that the testis structure in L. saxatilis cannot be attributed to the tubular type, as previously thought. It corresponds to the lobular cyst type but individual lobules contain cysts with gametes at the same stage of development. It is similar to the testis structure of several fishes, amphibians, and Drosophila melanogaster. This type of the gonad organization has never been described in gastropods before.

AB - Although individual stages of spermatogenesis in Littorina saxatilis are well studied at the electron microscopic level, the gonad structure and the spatial localization of gametes at different stages of maturation remain unclear. Using differential-interference contrast (DIC) for observations of fresh tissue we show that the mature testis consists of numerous ovoid lobules forming larger lobes. The lobules of intact mature testes of L. saxatilis are filled with randomly arranged multicellular cysts containing gametes at different stages of maturation. Gametes within a cyst are highly synchronized in respect of the differentiation degree. At the same time, no spatial gradient in the arrangement of cysts according to the maturation degree of gametes in them was observed in any of the studied lobules. The male gonads contain cysts with early spermatids, mid, late spermatids, and spermatozoa. Using silver-staining, DAPI, and chromomycin A3 (CMA3) staining, we identify 20 main types of nucleus organization in differentiating sperm. Premature and mature male gonads contain cysts with a mosaic arrangement as well as rare solitary cyst cells, goniablast cysts, or separate spermatogonia in between them. Our data indicate that the testis structure in L. saxatilis cannot be attributed to the tubular type, as previously thought. It corresponds to the lobular cyst type but individual lobules contain cysts with gametes at the same stage of development. It is similar to the testis structure of several fishes, amphibians, and Drosophila melanogaster. This type of the gonad organization has never been described in gastropods before.

KW - Cyst cells

KW - Cyst type of testis

KW - Germline cells

KW - Marine snails Littorina

KW - Stages of spermatocytogenesis

KW - CELLS

KW - FINE-STRUCTURE

KW - REGIONS

KW - SPERM MORPHOLOGY

KW - DROSOPHILA

UR - http://www.scopus.com/inward/record.url?scp=85061716745&partnerID=8YFLogxK

U2 - 10.1007/s00441-019-03004-y

DO - 10.1007/s00441-019-03004-y

M3 - Article

AN - SCOPUS:85061716745

VL - 376

SP - 457

EP - 470

JO - Cell and Tissue Research

JF - Cell and Tissue Research

SN - 0302-766X

IS - 3

ER -