In a companion paper in this journal, Amorim and coworkers reviewed recent human studies which show that Heat Shock Proteins (HSP72 and possibly HSP90) are elevated during heat acclimation. They suggest that these cellular changes result in both cellular and whole body thermotolerance. Thermotolerance after an initial sub-lethal heat exposure, has been shown repeatedly in cell studies, and has ...

This paper summarizes the findings from two recent studies involving the physiological effects of atropine (0 to 4 mg, im) on soldiers performing physical exercise in hot-dry environments. Study I determined the threshold of physiological effects and the gradation of these effects with increasing dosage of atropine. Study II examined the effects of exercise-heat acclimation on the reduced physi...

In an aerobic environment, responding to oxidative cues is critical for physiological adaptation (acclimation) to changing environmental conditions. The unicellular alga Chlamydomonas reinhardtii was tested for the ability to acclimate to specific forms of oxidative stress. Acclimation was defined as the ability of a sublethal pretreatment with a reactive oxygen species to activate defense resp...

Maloyan, Alina, Aaron Palmon, and Michal Horowitz. Heat acclimation increases the basal HSP72 level and alters its production dynamics during heat stress. Am. J. Physiol. 276 (Regulatory Integrative Comp. Physiol. 45): R1506–R1515, 1999.—It has been previously shown that heat acclimation leads to an elevated basal level of 72-kDa heat shock protein (HSP72). Augmented expression of HSP72 is cons...

Plants have evolved complex mechanisms to balance the efficient use of absorbed light energy in photosynthesis with the capacity to use that energy in assimilation, so avoiding potential damage from excess light. This is particularly important under natural light, which can vary according to weather, solar movement and canopy movement. Photosynthetic acclimation is the means by which plants alt...

The clustered genes C-repeat (CRT) binding factor (CBF)1/dehydration-responsive element binding protein (DREB)1B, CBF2/DREB1C, and CBF3/DREB1A play a central role in cold acclimation and facilitate plant resistance to freezing in Arabidopsis thaliana. Rice (Oryza sativa L.) is very sensitive to low temperatures; enhancing the cold stress tolerance of rice is a key challenge to increasing its yi...

Variation in respiratory traits was quantified between two populations of the sailfin molly Poecilia latipinna (one from a periodically hypoxic salt marsh, Cedar Key, and one from a chronically normoxic river site, Santa Fe River). Two suites of characters were selected: traits that may show both short-term acclimation response and interdemic variation in acclimation response (metabolic rate, c...

Cold poses major physiological challenges to plants, especially long-lived trees. In trees occurring along variable temperature clines, the expected direction and consequences of selection on cold acclimation ability and freezing tolerance are not straightforward. Here we estimated selection in cold acclimation genes at two evolutionary timescales in all seven species of the American live oaks ...

Acclimation of plants with an abiotic stress can impart tolerance to some biotic stresses. Such a priming response has not been widely studied. In particular, little is known about enhanced defense capacity of drought stress acclimated plants to fungal and bacterial pathogens. Here we show that prior drought acclimation in Nicotiana benthamiana plants imparts tolerance to necrotrophic fungus, S...

Striated muscle contraction is initiated when troponin C (TnC) binds Ca(2+), which activates actinomyosin ATPase. We investigated (i) the variation between cardiac TnC (cTnC) primary structure within teleost fish and (ii) the pattern of TnC expression in response to temperature acclimation. There were few differences between rainbow trout (Oncorhynchus mykiss), yellowfin tuna (Thunnus albacares...