The art of growing old: environmental manipulation, physiological rhythms, and the advent of Microcebus murinus as a primate model of aging

Fibrous Osteodystrophy, Chronic Renal Disease, and Uterine Adenocarcinoma in Aged Gray Mouse Lemurs (Microcebus murinus)

The gray mouse lemur (Microcebus murinus, GML) is a nocturnal, arboreal, prosimian primate that is native to Madagascar. Captive breeding colonies of GMLs have been established primarily for noninvasive studies on questions related to circadian rhythms and metabolism. GMLs are increasingly considered to be a strong translational model for neurocognitive aging due to overlapping histopathologic features shared with aged humans. However, little information is available describing the clinical presentations, naturally occurring diseases, and histopathology of aged GMLs. In our colony, a 9 y-old, male, GML was euthanized after sudden onset of weakness, lethargy, and tibial fracture. Evaluation of this animal revealed widespread fibrous osteodystrophy (FOD) of the mandible, maxilla, cranium, appendicular, and vertebral bones. FOD and systemic metastatic mineralization were attributed to underlying chronic renal disease. Findings in this GML prompted periodic colony-wide serum biochemical screenings for azotemia and electrolyte abnormalities. Subsequently, 3 additional GMLs (2 females and 1 male) were euthanized due to varying clinical and serum biochemical presentations. Common to all 4 animals were FOD, chronic renal disease, uterine adenocarcinoma (females only), cataracts, and osteoarthritis. This case study highlights the concurrent clinical and histopathologic abnormalities that are relevant to use of GMLs in the expanding field of aging research.

Wild Laboratories of Climate Change: Plants, Phenology, and Global Warming, 1955-1980

Phenologists track the seasonal behavior of plants and animals in response to climatic change. During the second half of the twentieth century, phenologists developed a large-scale project to monitor the flowering time of the common lilac (Syringa vulgaris) across the United States. By the 1960s, this approach offered a potential plant-based indicator of anthropogenic climate change, a biological signal amidst the emerging narrative of increasing levels of atmospheric carbon dioxide. As a tangible representation of changes in climate-warmer temperatures lead to earlier blooming-phenology proved highly legible to scientists, politicians, and laypeople. Yet, as phenology gained broader repute in the 1960s, both in agricultural stations and as a component program of the International Biological Program (IBP), it struggled to align itself epistemically with the regnant disciplinary assumptions of mid-century ecology. Operating in the hinterlands between laboratory and field, biology and meteorology, ecological theory and agronomy practice, phenologists challenged prevailing notions of the model organism and what it meant to study biology in the field. Rebranding the discipline as a component of ecosystem modeling, scientists successfully brought phenology within the purview of mainstream ecology. In so doing, however, they obscured its climate-relevant meteorological character and stymied the development of a biological narrative of climate change.