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Causes, Timing and Cost of Early Embryo Loss

by Troy Ott, Associate Professor of Reproductive Biology, Department of Dairy and Animal Science, Penn State

College of Agricultural Sciences

The College of Agricultural Sciences, the first of the colleges established at Penn State, awarded the nation's first baccalaureate degrees in agriculture in 1861. Today, the college is widely recognized as one of the nation's premier institutions for agricultural research and education programs.

College of Health and Human Development

Committed to improving the quality of your life is what the College of Health and Human Development is all about. Our work is relevant to people everywhere and we are leading the way in offering high-quality education to our students and in producing research that will positively affect the way we live today and in the future.

College of Medicine

Penn State College of Medicine is committed to enhancing the quality of life through improved health, the professional preparation of those who will serve the health needs of others, and the discovery of knowledge that will benefit all.

Colony stimulating factor 1 is an extrinsic stimulator of mouse spermatogonial stem cell self-renewal

Self-renewal and differentiation of spermatogonial stem cells (SSCs) provide the foundation for testis homeostasis, yet mechanisms that control their functions in mammals are poorly defined. We used microarray transcript profiling to identify specific genes whose expressions are augmented in the SSC-enriched Thy1+ germ cell fraction of mouse pup testes. Comparisons of gene expression in the Thy1+ germ cell fraction with the Thy1-depleted testis cell population identified 202 genes that are expressed 10-fold or higher in Thy1+ cells. This database provided a mining tool to investigate specific characteristics of SSCs and identify novel mechanisms that potentially influence their functions. These analyses revealed that colony stimulating factor 1 receptor (Csf1r) gene expression is enriched in Thy1+ germ cells. Addition of recombinant colony stimulating factor 1 (Csf1), the specific ligand for Csf1r, to culture media significantly enhanced the self-renewal of SSCs in heterogeneous Thy1+ spermatogonial cultures over a 63-day period without affecting total germ cell expansion. In vivo, expression of Csf1 in both pre-pubertal and adult testes was localized to clusters of Leydig cells and select peritubular myoid cells. Collectively, these results identify Csf1 as an extrinsic stimulator of SSC self-renewal and implicate Leydig and myoid cells as contributors of the testicular stem cell niche in mammals.

Department of Dairy and Animal Science

The Department of Dairy and Animal Science’s rich history of achievement and excellence dates from its inception in 1907. That’s nearly 100 years of making a difference in the lives of people – with important scientific discoveries, outstanding educational opportunities, and the latest in agricultural techniques. Today, the Department continues to build upon that tradition and strong heritage of leadership and distinction. We continuously strive to improve our service to our stakeholders - producers, processors, agribusinesses, and youth and rural residents.

Department of Poultry Science

The Department of Poultry Science employs a multidisciplinary approach to scholarship in teaching, research, and outreach. In addition to providing undergraduate and graduate education in the avian sciences and associated discipline areas, we conduct both fundamental and applied research, with many projects having direct application to the commercial poultry industry. We communicate our research findings via extension programs, at scientific conferences, in the scientific and popular press, and electronically. Our overall goal is to be recognized nationally and internationally as a center for scholarship and excellence in poultry science.

The Huck Institutes of the Life Sciences

The Huck Institutes catalyzes and facilitates excellence in interdisciplinary research and education in the life sciences at Penn State. It is dedicated to strengthening research in the life sciences, preparing students for successful careers, and encouraging new perspectives across disciplinary boundaries.