- B.A., Biochemistry, University of Kansas
- (Year Abroad) Physiology and Biochemistry of Farm Animals, University of Reading, England
- M.S., Animal Science, Purdue University
- Ph.D., Animal Science, Purdue University
A long-term focus in our laboratory is mammalian fertilization and the molecules involved in the fertilization process. Research is centered on interactions between sperm and oocyte plasma membrane molecules after sperm have undergone the acrosome reaction since our earlier work demonstrated that this was frequently the limiting step in vivo in subfertile animals. Details of these interactions including receptor/ligand pairings are still largely unknown. Environmental stresses such as elevated ambient temperature affect both the sperm’s ability and the oocyte’s ability to interact with each other at the plasma membrane level. We hypothesize that this is due to decreased/defective synthesis of interacting molecules.
A second focus in our laboratory is the regulation of Sertoli cell proliferation. Sertoli cell numbers are a major determinant of postpuberal testis size and sperm production. The number of Sertoli cells is generally believed to be determined prepuberally. We have found that reducing endogenous estrogen in the boars postnatally leads to increased proliferation of Sertoli cells and larger postpuberal testes in the pig. This occurs without altered pituitary hormones in boars and strongly suggests a locally mediated mechanism.
The pig is the primary species studied due in part to its importance to US and world food production as well as the availability of large numbers of gametes and comparatively short gestation and prepuberal intervals. In vitro oocyte maturation and fertilization, in vitro bioassays, gene expression (qPCR), immunohistochemistry, gel electrophoresis and western blotting, heterospermic insemination and other in vivo animal trials, CRISPR editing and embryo transfer are techniques used to advance our laboratory research goals.
- Physiology of Reproduction (NPB 121/121L)
- Mammalian Gametogenesis and Fertilization (MCP 222)
Stress and Reproduction (ANS 160A&B)
Current Graduate Students
- Javier Morales, Ph.D. Program, Animal Biology Graduate Group. Expected Graduation Date: Summer 2021.
- Kelly Zacanti, Ph.D. Program, Animal Biology Graduate Group. Expected Graduation Date: Summer 2021.
Recent Graduate Students
- Tana Almand, M.S.
- Jennifer Jankovitz, M.S.
- Kimberley Miller, M.S.
- Simin Tang, M.S.
At-Taras EE, Berger T, McCarthy MJ, Conley AJ, Nitta-Oda BJ, Roser JF. Reducing estrogen synthesis in developing boars increases testis size and total sperm production. J Androl 2006; 27: 552-559.
Berger T, McCarthy M, Pearl CA, At-Taras E, Roser JF, Conley A. Reducing endogenous estrogens during the neonatal and juvenile periods affects reproductive tract development and sperm production in postpuberal boars. Anim Reprod Sci 2007.
Kao E, Villalon R, Ribeiro S, Berger T. Role for endogenous estrogen in prepubertal Sertoli cell maturation. Anim Reprod Sci 2012; 135:106-112.
Berger T, Kentfield L, Roser JF, Conley A. Stimulation of Sertoli cell proliferation: defining the response interval to an inhibitor of estrogen synthesis in the boar. Reproduction 2012; 143: 523-529.
Conley AJ, Corbin CJ, Thomas JL, Gee NA, Lasley BL, Moeller BC, Stanley SD, Berger T. Costs and consequences of cellular compartmentalization and substrate competition among human enzymes involved in androgen and estrogen synthesis. Biology of Reproduction 2012; 86: (1) 1-8.
Berger T, Conley AJ, Van Klompenberg M, Roser JF, Hovey RC. Increased testicular Sertoli cell population induced by an estrogen receptor antagonist. Molecular and Cellular Endocrinology 2013; 366: 53-58.
Zamaratskaia G, Berger T. Skatole metabolism in the pigs with reduced testicular oestrogen synthesis. Reproduction in Domestic Animals 2014; 49(2): 302-305.
Berger T, Conley AJ. Reduced endogenous estrogen and hemicastration interact synergistically to increase porcine Sertoli cell proliferation. Biology of Reproduction 2014.
Berger T, Conley AJ. Reducing endogenous estrogen during prepuberal life does not affect boar libido or sperm fertilizing potential. Theriogenology 2014, 82: 627-35.
Legacki E, Conley AJ, Nitta-Oda BJ, Berger T. Porcine Sertoli Cell Proliferation after Androgen Receptor Inactivation. Biology of Reproduction 2015; 92:93.
Katleba K, Legacki EL, Conley AJ, Berger T. Steroid regulation of early postnatal development in the corpus epididymidis of pigs. Journal of Endocrinology 2015; http://dx.doi.org/10.1530/JOE-15-0001.
Tanphaichitr N, Kongmanas K, Kruevaisayawan H, Saewu A, Sugeng C, Fernandes J, Souda P, Angel JB, Faull KF, Aitken RJ, Whitelegge J, Hardy D, Berger T, Baker M. Remodeling of the plasma membrane in preparation for sperm-egg recognition: roles of acrosomal proteins. Asian Journal of Andrology 2015; 17(4): 1-9.
Hughes JR, Berger T. Development of apical blebbing in the boar epididymis. PLOS One 2015; 10(5):e0126848, 2015.
Hughes JR, Berger T. Regulation of apical blebbing in the porcine epididymis. J Anat. 2018; 232:515-522.
Berger T, Nitta-Oda BJ. 2018. Increased testicular estradiol during the neonatal interval reduces Sertoli cell numbers. Anim Reprod Sci. 189:146-151.
Berger, T, Sidhu P, Tang S, Kucera H. 2019. Are testicular cortisol and WISP2 involved in estrogen-regulated Sertoli cell proliferation? Anim Reprod Sci. 207: 44-51. doi: 10.1016/j.anireprosci.2019.05.014
Kucera H, Puschner B, Conley A, Berger T. 2019. Tissue steroid levels in response to reduced testicular estrogen synthesis in the male pig, Sus scrofa. PLOS One 14(4):e3900215. doi: 10.1371/journal.pone.0215390
Berger T. 2019. Testicular estradiol and the pattern of Sertoli cell proliferation in prepuberal bulls. Theriogenology 136:60-65. doi:10.1016/j.theriogenology.2019.06.031
Arias del Razo R, Berger T, Conley A, Freeman S, Goetze L, Jacob S, Larke R, Mendoza S, Rothwell E, Savidge L, Solomon M, Weinstein T, Witczak L, Bales K. 2020. Effects of chronic intranasal oxytocin on behavior and cerebral glucose uptake in juvenile titi monkeys. Psychoneuroendocrinology, 113:104494.
Berger T, Nitta-Oda BJ. 2020. Sertoli cell proliferation in juvenile boars and microRNA. Livestock Science 233:103954.
Berger, T., Tang, S., Tu, L., Soto, D.A., Conley, A.J. and Nitta-Oda, B., 2021. Changes in testicular gene expression following reduced estradiol synthesis: A complex pathway to increased porcine Sertoli cell proliferation, Mol Cell Endocrinol. 523, 111099.
Vanselow, J., Conley, A.J. and Berger, T., 2021. Aromatase and the three little paralogs, Biol Reprod. https://academic.oup.com/biolreprod/advance-article-abstract/doi/10.1093/biolre/ioab112/6294498?redirectedFrom=fulltext
Vanselow, J., Conley, A.J., Corbin, C.J. and Berger, T., 2021. Genomic Structure of the Porcine CYP19 Locus and Expression of the CYP19A3 Paralog, Genes (Basel). 12. https://www.mdpi.com/2073-4425/12/4/533