Effect of transitional photoperiods on testicular development and puberty in male deer mice (Peromyscus maniculatus)

Altricial mammals begin to independently thermoregulate during the first few weeks of postnatal development. In wild rodent populations, this is also a time of high mortality (50–95%), making the physiological systems that mature during this period potential targets for selection. High altitude (HA) is a particularly challenging environment for small endotherms owing to unremitting low O 2 and ambient temperatures. While superior thermogenic capacities have been demonstrated in adults of some HA species, it is unclear if selection has occurred to survive these unique challenges early in development. We used deer mice ( Peromyscus maniculatus ) native to high and low altitude (LA), and a strictly LA species ( Peromyscus leucopus ), raised under common garden conditions, to determine if postnatal onset of endothermy and maturation of brown adipose tissue (BAT) is affected by altitude ancestry. We found that the onset of endothermy corresponds with the maturation and activation of BAT at an equivalent age in LA natives, with 10-day-old pups able to thermoregulate in response to acute cold in both species. However, the onset of endothermy in HA pups was substantially delayed (by approx. 2 days), possibly driven by delayed sympathetic regulation of BAT. We suggest that this delay may be part of an evolved cost-saving measure to allow pups to maintain growth rates under the O 2 -limited conditions at HA.

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Development and Characterization of a Sin Nombre Virus Transmission Model in Peromyscus maniculatus

Viruses ◽

10.3390/v11020183 ◽

2019 ◽

Vol 11 (2) ◽

pp. 183 ◽

Cited By ~ 5

Author(s):

Bryce Warner ◽

Derek Stein ◽

Bryan Griffin ◽

Kevin Tierney ◽

Anders Leung ◽

...

Keyword(s):

Peromyscus Maniculatus ◽

Deer Mouse ◽

Virus Transmission ◽

Transmission Model ◽

Deer Mice ◽

Sin Nombre Virus ◽

Infection Model ◽

Main Driver ◽

Heat Shock Responses

In North America, Sin Nombre virus (SNV) is the main cause of hantavirus cardiopulmonary syndrome (HCPS), a severe respiratory disease with a fatality rate of 35–40%. SNV is a zoonotic pathogen carried by deer mice (Peromyscus maniculatus), and few studies have been performed examining its transmission in deer mouse populations. Studying SNV and other hantaviruses can be difficult due to the need to propagate the virus in vivo for subsequent experiments. We show that when compared with standard intramuscular infection, the intraperitoneal infection of deer mice can be as effective in producing SNV stocks with a high viral RNA copy number, and this method of infection provides a more reproducible infection model. Furthermore, the age and sex of the infected deer mice have little effect on viral replication and shedding. We also describe a reliable model of direct experimental SNV transmission. We examined the transmission of SNV between deer mice and found that direct contact between deer mice is the main driver of SNV transmission rather than exposure to contaminated excreta/secreta, which is thought to be the main driver of transmission of the virus to humans. Furthermore, increases in heat shock responses or testosterone levels in SNV-infected deer mice do not increase the replication, shedding, or rate of transmission. Here, we have demonstrated a model for the transmission of SNV between deer mice, the natural rodent reservoir for the virus. The use of this model will have important implications for further examining SNV transmission and in developing strategies for the prevention of SNV infection in deer mouse populations.

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