Physiological Regulation and Conformation: A BASIC Program for the Determination of Critical Points

Yeager, Dorian P.; Ultsch, Gordon R.

doi:10.1086/physzool.62.4.30157935

Cited by 292 publications

(189 citation statements)

References 12 publications

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“…Time from the start of exposure to LOE was noted and, for the fish where the data allowed, i.e., LOE occurred after the drop of MO 2 below SMR, a point of no return (PNR) was calculated as the time post-exposure where MO 2 fell below SMR. PNR was calculated using a stick regression similar to that of Yeager and Ultsch [35] (Figure 1). The measure was calculated in Python 2.7 using the Numpy and Scipy libraries.…”

Section: Loss Of Equilibrium and Time To The Point Of No Returnmentioning

confidence: 99%

“…Fishes 2018, 3, 12 4 of 12 similar to that of critical oxygen levels [34][35][36], using exposure time as a variable instead of oxygen level. As such, the PNR provides an average measure of the duration for which the fish can maintain their required oxygen consumption when continuously exposed to P. parvum.…”

Section: Loss Of Equilibrium and Time To The Point Of No Returnmentioning

confidence: 99%

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Effects of Harmful Algal Blooms on Fish: Insights from Prymnesium parvum

Svendsen

Andersen

Hansen

et al. 2018

Fishes

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Blooms of the planktonic alga Prymnesium parvum pose a global threat, causing fish kills worldwide. Early studies on the exposure of fish to P. parvum indicate that toxic effects are related to gill damage. The more strictly defined concept of adverse outcome pathways has been suggested as a replacement for the mode of action in toxicology studies. In this study, rainbow trout (Onchorhyncus mykiss) were exposed to P. parvum. During exposure, oxygen consumption was determined by respirometry, and ventilation and coughing rate were determined via video surveillance. Per breath oxygen consumption was calculated to assess the ventilation effort to obtain a unit of oxygen. A second experiment monitored fish behavior to assess recovery. The results indicated that oxygen consumption initially increased, but on average fell below the standard oxygen consumption at 70% relative exposure. Being a function of ventilation frequency and oxygen consumption, the per breath oxygen consumption decreased throughout exposure. Behavioral results determined that short-term P. parvum exposure subsequently caused the exposed fish to seek flow refuge immediately and to a greater extent than unexposed fish. The adverse outcome pathway of P. parvum on rainbow trout is that P. parvum acts as a gill irritant resulting in non-recoverable respiratory failure.

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Section: Loss Of Equilibrium and Time To The Point Of No Returnmentioning

confidence: 99%

Section: Loss Of Equilibrium and Time To The Point Of No Returnmentioning

confidence: 99%

Effects of Harmful Algal Blooms on Fish: Insights from Prymnesium parvum

Svendsen

Andersen

Hansen

et al. 2018

Fishes

View full text Add to dashboard Cite

show abstract

“…We calculated the T AB of f Hmax using the program presented in [28]. This program fits two-segmented straight lines, which allowed us to identify the point at which temperature-induced increases in f Hmax shift to a lower exponent.…”

Section: (D) Statistical Analysesmentioning

confidence: 99%

Indirect genetic effects underlie oxygen-limited thermal tolerance within a coastal population of chinook salmon

et al. 2014

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With global temperatures projected to surpass the limits of thermal tolerance for many species, evaluating the heritable variation underlying thermal tolerance is critical for understanding the potential for adaptation to climate change. We examined the evolutionary potential of thermal tolerance within a population of chinook salmon (Oncorhynchus tshawytscha) by conducting a full-factorial breeding design and measuring the thermal performance of cardiac function and the critical thermal maximum (CT max ) of offspring from each family. Additive genetic variation in offspring phenotype was mostly negligible, although these direct genetic effects explained 53% of the variation in resting heart rate ( f H ). Conversely, maternal effects had a significant influence on resting f H , scope for f H , cardiac arrhythmia temperature and CT max . These maternal effects were associated with egg size, as indicated by strong relationships between the mean egg diameter of mothers and offspring thermal tolerance. Because egg size can be highly heritable in chinook salmon, our finding indicates that the maternal effects of egg size constitute an indirect genetic effect contributing to thermal tolerance. Such indirect genetic effects could accelerate evolutionary responses to the selection imposed by rising temperatures and could contribute to the population-specific thermal tolerance that has recently been uncovered among Pacific salmon populations.

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“…Solid lines in graphs indicate significant regression curves, with broken lines depicting the 95% confidence interval. When regressions were significant, a critical point of transition to non-steady state metabolism was determined following a method described by Yeager and Ultsch (1989). For this, the data were sorted into descending order using oxygen tension as a key parameter.…”

Section: Statisticsmentioning

confidence: 99%

Metabolic performance of the squid Lolliguncula brevis (Cephalopoda) during hypoxia: an analysis of the critical PO2

Zielinski

Lee

Pörtner

2000

Journal of Experimental Marine Biology and Ecology

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Brief squid Lolliguncula brevis are regularly exposed to fluctuating oxygen levels in their shallow coastal environment. To assess hypoxia resistance, animals were exposed for two hours to ambient oxygen partial pressures (P ) between 19.3 kPa (normoxia) and 6.6 kPa (34.2% air O 2 saturation) at 20618C. In a second set of experiments, the animals were subjected to a low P of O 2 2.860.3 kPa (14.561.6% air saturation) for 15 to 60 min. Subsequently, metabolic, energy and acid-base status were analysed in the mantle tissue. Onset of anaerobic metabolism was observed between 9.4 and 7.9 kPa (48.7 and 40.9% air saturation), reflecting the critical oxygen tension for this species. The formation of octopine and acetate indicates a simultaneous onset of anaerobic metabolism in both the cytosol and the mitochondria during progressive hypoxia. Concomitantly, an intracellular acidosis developed. During exposure to oxygen partial pressures between 19.3 and 6.6 kPa, aerobic and anaerobic processes were sufficient to maintain energy status in the mantle musculature. No significant changes in ATP and phospho-L-arginine (PLA) concentrations were observed. In contrast, both ATP and PLA levels declined significantly after 15 min at an ambient P of 2.860.3 kPa. Concomitantly, the Gibb's free energy change of ATP hydrolysis fell to a O 2 21minimum value of about 244 kJ?mol , a level suggested to reflect limiting energy availability for cellular ATPases. These results indicate that hypoxia at 2.8 kPa (14.5% air saturation) rapidly takes Lolliguncula brevis to the limits of performance. However, it is probably capable of withstanding longer periods of moderate hypoxia close to 50% air saturation (9.7 kPa), enabling the squids to cope with oxygen fluctuations in their shallow estuarine environment or to dive into hypoxic waters by use of their economic jetting strategy. Nonetheless, the critical P is O 2 considered to be high compared to other hypoxia tolerant animals, an observation likely related to the high metabolic rate of these squids.

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Physiological Regulation and Conformation: A BASIC Program for the Determination of Critical Points

Cited by 292 publications

References 12 publications

Effects of Harmful Algal Blooms on Fish: Insights from Prymnesium parvum

Effects of Harmful Algal Blooms on Fish: Insights from Prymnesium parvum

Indirect genetic effects underlie oxygen-limited thermal tolerance within a coastal population of chinook salmon

Metabolic performance of the squid Lolliguncula brevis (Cephalopoda) during hypoxia: an analysis of the critical PO2

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