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Stereological analysis of nutritive phagocytes and gametogenic cells during the annual reproductive cycle of the green sea urchin, Strongylocentrotus droebachiensis
Author(s) -
Harrington Laura H.,
Walker Charles W.,
Lesser Michael P.
Publication year - 2007
Publication title -
invertebrate biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.486
H-Index - 42
eISSN - 1744-7410
pISSN - 1077-8306
DOI - 10.1111/j.1744-7410.2007.00090.x
Subject(s) - strongylocentrotus droebachiensis , gametogenesis , biology , sea urchin , germinal epithelium , sertoli cell , reproductive biology , microbiology and biotechnology , mitosis , strongylocentrotus purpuratus , zoology , spermatogenesis , embryo , endocrinology , embryogenesis
. The germinal epithelium of sea urchin gonads contains two interdependent populations of cells: somatic cells called nutritive phagocytes (NPs) and germ cells—ovarian and testicular gonial cells and their derivatives, gametocytes and gametes. Annually, NPs vary their structure and function to produce a changing microenvironment for germ cells during gametogenesis and after spawning. Here, we describe seasonal changes in the NPs as they interact with germ cells during successive gametogenic stages in both sexes of the green sea urchin, Strongylocentrotus droebachiensis. Monthly samples were collected from the Gulf of Maine at a depth of 10 m and analyzed with light microscopy and stereology. Shorter day length and falling seawater temperatures were correlated with nutrient mobilization from NPs, initiation of gonial cell mitosis, and subsequent gametogenesis. During gametogenesis, NPs in both sexes were depleted of nutrients and eventually phagocytize residual ova or spermatozoa. Observations from this study are important for understanding both the cellular aspects of the reproductive biology of sea urchins and those environmental factors that affect the onset and progress of gametogenesis.