Reproduction & Endocrinology
- Bursian, Steve (toxicology, animal health, environment)
- Chou, Karen (toxicology, animal health, reproduction)
- Cibelli, Jose (cellular reprogramming, nuclear transfer, embryonic stem cells)
- Ireland, James (endocrinology of reproduction, fertility, functional genomics)
- Pursley, Richard (dairy reproductive management, ovarian physiology)
- Smith, George (reproduction, ovarian function, stress physiology, functional genomics)
- VandeHaar, Michael (dairy nutrition, endocrinology, mammary physiology)
Steven J. Bursian, Professor
Principle Investigator, Animal Toxicology Laboratory
Katrina L. Shields, Research Assistant/Laboratory Coordinator
Our laboratory studies the effects of natural toxins such as mycotoxins and environmental contaminants such as PCBs and dioxins on animals. For the past 40 years, past and present members of our group have worked with mink and have contributed significantly to the extensive database regarding not only the biology of this species, but also the unique sensitivity of the mink to persistent environmental contaminants. Most recently, we have conducted a number of feeding trials with mink that assessed the reproductive and health effects of environmentally derived chemical contaminants from specific areas of concern such as the Saginaw River in Michigan and the Housatonic River in Massachusetts. We are also studying a unique lesion of the jaw that occurs in mink exposed to specific chlorinated contaminants that are common in the environment. Additionally, we have conducted a number of studies that have examined the effects of common environmental contaminants as well as emerging contaminants on avian embryo development. We are fortunate to have a number of fellow scientists not only at MSU but at other research facilities throughout the word, that collaborate with us on our studies. The data that this laboratory has generated over the years have been and will continue to be important information incorporated into ecological risk assessments.
My laboratory studies the exposure and health effects of environmental chemicals in mammalian species, with a focus on developmental and reproductive toxicity. The laboratory examines the mechanism of toxicity of pesticides and endocrine disruptors on testicular function, sperm and egg production, and fertility. The target mechanisms include the functions of endocrine systems, production of reactive oxygen species, and the relationship between clusters of alternations in gene expression and long-term reproductive performance. A second major focus of my laboratory is the development of improved semen preservation methods for livestock. The study models include laboratory animals, livestock, and cultured gametes.
Our Cellular Reprogramming Laboratory focuses in two aspects of developmental biology. (1) Nuclear Transfer—Cloning: A number of different laboratories, including our own, have demonstrated that a somatic (body) cell, once fused with an egg, is capable of generating not only stem cells (ref 1) but a whole new organism as well (refs 2-4). Interestingly, we still do not comprehend how this is possible. Our laboratory focuses on understanding the molecular events that lead to the transformation of a somatic nucleus into an embryonic-pluripotent one. Insights into the mechanism of de-differentiation will help us generate cloned animals at optimal efficiency for their use in agriculture and medicine (ref 5). (2) Primate Embryonic Stem Cells: Embryonic stem (ES) cells are capable of maintaining an undifferentiated or ‘pluripotent’ state in vitro. At the same time, by modifying the culture conditions, they can generate daughter cells capable of forming all the tissues in the body. We have demonstrated that somatic cells can be turned into ES cells either by nuclear transfer (cloning; ref 1) or by parthenogenesis (ref 6), and that these cells can later be induced to differentiate into multiple complex tissues (ref 6). In order for us to understand how the state of pluripotency is reached and maintained, ES cells are carefully analyzed at the molecular level. Our challenge is now to learn how to produce these cells without having to relay on eggs (ref 7).
Cibelli JB, Stice SL, Golueke PJ, et al. (1998) Transgenic bovine chimeric offspring produced from somatic cell-derived stem-like cells. Nat Biotechnol 16: 642-646.
Cibelli JB, Stice SL, Golueke PJ, et al. (1998) Cloned transgenic calves produced from nonquiescent fetal fibroblasts. Science 280: 1256-1258.
Lanza RP, Cibelli JB, Blackwell C, et al. (2000) Extension of cell life-span and telomere length in animals cloned from senescent somatic cells [see comments]. Science 288: 665-669.
Lanza RP, Cibelli JB, Faber D, et al. (2001) Cloned cattle can be healthy and normal. Science 294: 1893-1894.
Cibelli JB, Campbell KH, Seidel GE, West MD, Lanza RP. (2002) The health profile of cloned animals. Nat Biotechnol 20: 13-14.
Cibelli JB, Grant KA, Chapman KB, et al. (2002) Parthenogenetic stem cells in nonhuman primates. Science 295: 819.
Cibelli J, Kiessling A, Cunniff K, Richards C, Lanza R, West M. (2001) Somatic Cell Nuclear Transfer in Humans: Pronuclear and Early Embryonic Development. e-biomed: The Journal of Regenerative Medicine Volume 2.
James J. Ireland. Professor
Director, Molecular Reproductive Endocrinology Laboratory
Depts. Animal Science and Physiology
Janet L.H. Ireland, Laboratory Coordinator
Fermin Jimenez-Krassel, Chief Research Associate
Our laboratory focuses on elucidation of the physiological role hormones, growth factors and cytokines have in regulation of selection, growth, and function of dominant follicles in cattle; and on use of molecular technology (DNA array, real-time PCR) to identify new genes potentially involved in aging-induced alterations in selection, growth, differentiation and function of dominant follicles. We are keenly interested in identification of the intrafollicular factors that regulate aromatase activity in granulosa cells of dominant follicles because of the pivotal physiological role estradiol has in reproduction and other non-reproductive processes. From a practical standpoint, we are interested in development of new diagnostic methods to identify cattle with superior fertility. Our laboratory has considerable expertise in large animal surgery (including utero-ovarian vein cannulations for blood sampling and ovariectomy), ultrasound analysis of follicular development, ultrasound-guided needle biopsy of ovarian follicles, ultrasound-guided intrafollicular injection of drugs, ELISA, RIA, Northern and immunoblot analysis, DNA array, PCR, protein purification, antibody development, and cell culture.
Our group does research and subsequent extension of reproductive management strategies to enhance profitability of dairy production. In particular we study ovarian physiology in cattle with primary emphasis on follicular development. We are also studying hormonal control of follicular growth to synchronize ovulation and to increase embryo production in superstimulated cows.
Research efforts in the Molecular Animal Reproduction and Neuroendocrinology Laboratory have focused on investigation of fundamental mechanisms that regulate ovarian function in farm animals and the physiological and neuroendocrine mechanisms involved in regulation of the stress response. We have obtained new insight into the hormonal regulation and regulatory role of members of the matrix metalloproteinase gene family in control of follicle rupture and the hormonal regulation and physiological role of various components of the corticotropin releasing factor (CRF) system in promoting the stress response. Recent research efforts also utilize functional genomics approaches to identify specific components of the oocyte transcriptome [catalog of genes expressed in the female germ cell] that play a key role in regulation of folliculogenesis, oocyte function and early embryonic development, and to identify objective molecular markers that are predictive of oocyte competence and subsequent potential reproductive success post-fertilization.
My research program includes dairy nutrition and mammary physiology, replacement heifer nutrition and management and nutrition modeling. The major research focus is to identify mechanisms by which nutrition alters mammary development of dairy heifers with emphasis on leptin and the insulin-like growth factor system.