Skip to main content

Germ cell line during the seasonal sexual rest of clams: finding niches of cells for gonad renewal


Reconstitution and renewal of tissues are key topics in developmental biology. In this brief work, we analyzed the wintry spent phase of the reproductive cycle in the Manila clam Ruditapes philippinarum (Bivalvia, Veneridae) in order to study the gonad rebuilding that in this species occurs at the beginning of the warmer months. We labeled VASA homolog protein—a germ cell marker—and compared the histological observations of the spent phase with those of the previously analyzed gametogenic phase. In R. philippinarum, during the reproductive season, most of the body mass is represented by sack-like structures (acini) full of developing gametes. In that period, VASA-stained cells are present at the basal pole of the gut epithelium, in the connective tissue, and around the acini. We here show that during the spent phase large portions of the intestine lack such cell type, except for some areas showing a few faintly VASA-stained cells. Cells with similar nuclear morphology are present among loosely organized cells of connective tissue, sometimes as single units, sometimes in small groups, rarely partially organized in primordial gonadic structures. These observations match the findings of RNA-targeting studies that during the spent phase identified the source of bivalve germ cells within the connective tissue in the form of quiescent units and add new information on the possible maintenance of VASA-stained, multipotent cells among the batiprismatic cells of the intestine during the whole life span of these bivalves.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3


Download references


We would like to thank Edoardo Turolla (Istituto Delta Ecologia Applicata, Ferrara, Italy) for providing Ruditapes philippinarum specimens, and Simone Bettini for his help in histological sample preparation.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Liliana Milani.

Ethics declarations

Ethics approval

All applicable international, national, and/or institutional guidelines for the care and use of animals were followed, in accordance with the Directive 2010/63/EU.

Conflict of interest

The authors declare that they have no competing interests.


This study was funded by the Italian Ministry of Education, University and Research MIUR-SIR Programme (Grant Number RBSI14G0P5) funded to LM, by the Italian Ministry of Education, University and Research MIUR-FIR Programme (Grant Number RBFR13T97A) funded to FG, and by 2014 RFO funding University of Bologna to MGM.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Supplementary material 1 (TIFF 10918 kb)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Milani, L., Pecci, A., Ghiselli, F. et al. Germ cell line during the seasonal sexual rest of clams: finding niches of cells for gonad renewal. Histochem Cell Biol 149, 105–110 (2018).

Download citation

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


  • VASA
  • DEAD-box RNA helicase
  • Multipotent stem cells
  • Gonad development
  • Ruditapes philippinarum