Wednesday: Grand Challenges in Physiology

Image from the American Physiological Society's website.
http://www.the-aps.org/mm/Conferences/APS-Conferences/2014-Conferences/…

Wednesday was the last day of the meeting that culminated in a closing banquet with an awards session to honor students who had exceptional presentations. What an impressive group of young comparative physiologists!  The plenary lecture was given by Dr. Steven Chown (Monash Univ, Australia). He spoke about climate change forecasts and continuing environmental changes and how important it is to understand how animals adapt to changing conditions in order to make ecophysiological predictions.

Other highlights from throughout the final day of the meeting included:

A series of lectures that were focused on understanding and modeling responses to stress in animals to help predict when populations may be at risk of declining before it happens.

Finkelstein A, Derdikman D, Rubin A, Foerster JN, Las L, Ulanovsky N (Weizmann Inst of Sci; Israel Inst of Tech). There are neurons in brain that are called 'head-direction cells'. These are responsible for informing an animal when their head is oriented in a specific direction, which is important for orientation when navigating in a three-dimensional space.

Dr. John Cockrem (Massey Univ, New Zealand) spoke about how birds release the hormone corticosterone when they perceive or experience a threat. This response to stress can vary between birds. Birds that have lower stress responses (indicated by lower corticosterone release) are considered to be more successful under predictable conditions. In contrast, birds with large stress responses may be more successful under unpredictable or changing conditions, which may help them to deal with environmental changes better than birds with lower stress responses.

13-lined ground squirrel hibernation is broken up by intermittent bouts of arousal during which time the animal wakes up from torpor (See figure below).

Figure 1: showing hibernation of a 13-line ground squirrel with intermittent bouts of arousal and torpor. March 16, 2009, doi:
10.1113/jphysiol.2008.167692

Ballinger M, Napolitano M, Bjork J, Andrews MT (Univ Minnesota) discussed how brown fat (i.e. brown adipose tissue), which the animals build up before hibernation, is important for producing heat that enables them to have these intermittent bouts of arousal. Notice in the image above how the body temperature ranges from ~37degC when they are awake down to only about 3-5degC when they are in torpor.

Grabek K, Hesselberth J, Barsh G, Behn CD, Martin S (Univ Colorado (Denver); HudsonAlpha Inst Biotech) also discussed how brown fat cycles between a more dormant state (torpor) to an active state (arousal) to match the metabolism of the whole animal during those phases. They discovered that the genome of the brown fat actually changes during these different phases to allow for the rapid production of various proteins needed to produce heat (thermogenesis).

Wone B, Ojha J, Davidowitz (Univ Nevada-Reno; Univ Arizona) presented data that showed hawkmoths (Manduca sexta) are good models of disease and aging in skeletal muscle because their flight muscles are similar, metabolically-speaking, to vertebrate skeletal muscle. Who knew?

Image of Manduca sexta from Wikimedia Commons.