Taconic Insights

An elegant new study proves "natural" microbiomes can be transferred to, and maintained in, SPF laboratory mice. The Problem with SPF Mice Historically, laboratory mice have been valued for their well-defined genetics and a health profile free from mouse pathogens. Over the last thirty years, efforts have been made to improve the health of laboratory mice by removing organisms that are deemed pathogenic. That list is now...

This is the second of a four-part series on the effective use of cryopreservation in maintaining genetically modified mouse and rat lines: Cryopreservation in Colony Management Introduction to Embryo Cryopreservation Sperm Cryopreservation Overview Cryopreservation Decision Tree Embryo Cryopreservation Overview Until recently, cryopreservation of two-cell stage or later stage embryos was the predominant method for preserving lines of laboratory rodent models. The methodology is relatively simple and does...

Human Vaccine Evaluation in a Novel Humanized Immune System Mouse The evaluation of specific antibody production requires an in vivo model; however, species differences limit the utility of experimental animals for this purpose. For example, the lack of interspecies homology between the T cell receptor (TCR) repertoire and major histocompatibility complex (MHC) proteins precludes the evaluation of human vaccine responses in rodents. Humanized mice could be the...

Use of genetically engineered rodent models in research requires the lines to be maintained in continuous breeding, which is costly, labor intensive, and takes up limited vivarium space. Also when such colonies are the sole source of the model, there is risk of losing the line altogether to unanticipated death, disease, infertility, genetic drift, or microbial contamination. Effective use of cryopreservation allows researchers to better utilize financial...

While wild type mice administered GDF15 lose weight, Gfral knockout mice are resistant to the effects of GDF15. Figure from Hsu, J-Y, et al1. Four independent research groups recently identified the previously orphan receptor GFRAL as the receptor for GDF15. The simultaneous publications, one in Nature1 and three in Nature Medicine2,3,4, show that GFRAL expression is restricted to brainstem regions in mice and that GDF15 acts through...

Gnotobiotics, edited by Trenton Schoeb and Kathryn Eaton, is invaluable to those developing or managing gnotobiotic facilities. The book is part of the American College of Laboratory Animal Medicine Series, published by Elselvier, and covers a number of species including rodents, swine and fish. It is assembled from contributions by nineteen authors with firsthand experience managing gnotobiotic facilities. James Fox nicely captures the essence of this book...

Researchers have identified measurable effects of exercise on the gut microbiome in mice, according to a study published in mSystems. In "Moderate Exercise Has Limited but Distinguishable Effects on the Mouse Microbiome," researchers at Dalhousie University, Canada, compared gut microbial diversity and changes in exercise-associated inflammatory markers over an 8-week period in sedentary mice and mice that performed either voluntary or moderate forced exercise. They found levels...

Anthony St. Leger and colleagues from the National Eye Institute at the National Institute of Health (NIH) recently published evidence that the ocular microbiome plays an important immunological role1. The Ocular Microbiome The surface of the human body is colonized by a diverse community of microorganisms, and the eye is no exception. Yet the ocular surface contains relatively few bacteria, approximately 150-fold fewer than the mouth2. Many...

Segmented filamentous bacteria (SFB) in the terminal ileum of an 8-week-old Taconic B6 mouse On September 13, 2017 researchers from the Massachusetts Institute of Technology and the University of Massachusetts Medical School simultaneously published papers in Nature on the same intriguing topic: a link between autism and infection during pregnancy. Previous epidemiological studies have shown an association between hospitalization during pregnancy due to severe infection and the...

In the spirit of Russell and Burch's 3Rs, scientists are developing new tools and methodologies to reduce the use of animal models wherever possible. A very good example is the rasH2 mouse model, which was developed as an alternative to the traditional, two-year carcinogenicity testing of compounds for mutagenic and non-mutagenic chemically- induced tumor formation. Transgenic Mice as an Ethical Alternative The rasH2 mouse was developed in...