Mammalian spermatogenesis is maintained by spermatogonial stem cells (SSCs). However, since evidentiary assays and unequivocal markers are still missing in non-human primates (NHPs) and man, the identity of primate SSCs is unknown. In contrast, in mice, germ cell transplantation studies have functionally demonstrated the presence of SSCs. LIN28 is an RNA-binding pluripotent stem cell factor, wh...

In the adult mammalian testis, spermatogenic differentiation starts from a minute population of spermatogonial stem cells (SSCs). SSCs are generated after birth from the fetal gonocytes, themselves derived from the primordial germ cells (PGCs), which are specified during the first days after implantation. Transcriptome profiling of purified preparations evidenced the preferential accumulation i...

The decline of quantity and quality of sperm are correlated with the increasing age and some anti-cancer compounds such as busulfan. Previous studies have shown that Resveratrol (Res) inhibits tumorigenesis and metastasis of many cancers including mammary tumor, prostate and pancreatic cancers. It acts as anti-age in mouse and human, however, little is known about its protective effect on aged ...

objective: spermatogonial stem cells (sscs) are the only cell type that can restore fertility to an infertile recipient following transplantation. much effort has been made to develop a protocol for differentiating isolated sscs in vitro. recently, three-dimensional (3d) culture system has been introduced as an appropriate microenvironment for clonal expansion and differentiation of sscs. this ...

Spermatogenesis is a complex series of cellular changes leading to the formation of haploid male gametes (spermatozoa) and includes mitotic, meiotic and post-meiotic phases. Spermatogonial stem cells (SSCs) are essential for the continuous lifelong production of spermatozoa. Spermatogenesis is initiated when SSC is triggered to undergo mitosis that gives rise to progenitors, which further diffe...

Spermatogenesis requires retinoic acid (RA) induction of the undifferentiated to differentiating transition in transit amplifying (TA) progenitor spermatogonia, whereas continuity of the spermatogenic lineage relies on the RA response being suppressed in spermatogonial stem cells (SSCs). Here, we discovered that, in mouse testes, both spermatogonial populations possess intrinsic RA-response mac...

The use of skeletal stem cells (SSCs) for cell-based therapies is currently one of the most promising areas for skeletal disease treatment and skeletal tissue repair. The ability for controlled modification of SSCs could provide significant therapeutic potential in regenerative medicine, with the prospect to permanently repopulate a host with stem cells and their progeny. Currently, SSC differe...

Mammalian spermatogenesis is a classic adult stems cell-dependent process, supported by the self-renewal and differentiation of spermatogonial stem cells (SSCs). However, the identification of SSCs and elucidation of their behaviors in undisturbed testis has long been a big challenge. Here, we generated a knock-in mouse model, Id4-2A-CreERT2-2A-tdTomato, which allowed us to mark Id4-expressing ...

Super star clusters (SSCs) are the most extreme star forming environments in the local universe. Packed with massive stars, these clusters have a major impact on the energetics and morphology of galaxies. Massive stars ionize the interstellar medium and power the infrared radiation of dust, and their stellar winds and supernovae release mechanical energy that can trigger further star formation....

The Next Generation Science Standards (NGSS), a reform effort “for states, by states,” advances ambitious ideals for elementary science teaching, but the fate of these will depend in part on engagement state coordinators (SSCs). This article explores responses SSCs to NGSS purposeful sample 18 US states. Based analysis 19 interviews with 22 SSCs, we develop two arguments. First, SSCs' ideas abo...