Diego Bernales

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Judith L Green

University of California, Santa Barbara

E. Wayne Ross

University of British Columbia

Don Ross

University College Cork

Alejandra B Osorio

Wellesley College

Steffen Boehm

University of Exeter

Armando Marques-Guedes

UNL - New University of Lisbon

Giulia Sissa

Ucla

Renzo Ramirez-Bacca

Universidad Nacional de Colombia (National University of Colombia)

J.-C. Spender

Kozminski University

Daniel Hershenzon

University of Connecticut

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Papers by Diego Bernales

The Use of Carbohydrate Profiles and Chemometrics in the Characterization of Natural Honeys of Identical Geographical Origin

Journal of Agricultural and Food Chemistry, 2005

A study of the real possibilities of carbohydrate profiles and chemometrics to characterize the b... more A study of the real possibilities of carbohydrate profiles and chemometrics to characterize the botanical origin of honey from a single geographical area, the Province of Soria (Spain), is presented. To this end, 14 carbohydrates were quantified using high-performance liquid chromatography (HPLC) with pulsed amperometric detection (PAD) in 77 natural honeys, the botanical origins of which were ling, spike lavender, French lavender, thyme, forest, and multifloral. Principal component analysis has been employed as a first approach to characterize the honey samples analyzed, showing similarities between spike lavender and multifloral honeys. The best discrimination among groups is obtained when four canonical discriminant analyses were carried out sequentially, origin by origin, achieving an overall percentage of success of 90% following cross-validation.

Divergent locomotor muscle design among thresher sharks

Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2009

Through convergent evolution tunas and lamnid sharks share thunniform swimming and a medial posit... more Through convergent evolution tunas and lamnid sharks share thunniform swimming and a medial position of the red, aerobic swimming musculature. During continuous cruise swimming these muscles move uniformly out of phase with local body curvature and the surrounding white muscle tissue. This design results in thrust production primarily from the caudal fin rather than causing whole-body undulations. The common thresher shark (Family Alopiidae) is the only other fish known to share the same medial red muscle anatomy as the thunniform swimmers. However, the overall body shape and extremely heterocercal caudal fin of the common thresher is not shared with the thunniform swimmers, which have both fusiform bodies and high aspect-ratio, lunate caudal fins. Our study used sonomicrometry to measure the dynamics of red and white muscle movement in common thresher sharks swimming in the ocean to test whether the medial position of red muscle is associated with uncoupling of muscle shortening and local body bending as characteristic of thunniform swimmers. Common threshers (∼ 60-100 kg) instrumented with sonomicrometric and electromyographic (EMG) leads swam alongside of the vessel with a tail-beat frequency of ∼ 0.5 Hz. EMG signals confirmed that only the red muscle was active during sustained swimming. Despite the more medial position of the red muscle relative to the white muscle, its strain was approximately 1.5-times greater than that of the overlying white muscle, and there was a notable phase shift between strain trajectories in the red muscle and adjacent white muscle. These results suggest an uncoupling (shearing) of the red muscle from the adjacent white muscle. Although the magnitude of the phase shift between red and white muscle strain was relatively constant within individuals, it varied among sharks, ranging from near zero (red and white in phase) to almost 180°out of phase. This extent in variability has not been documented previously for thunniform swimmers with a medial red muscle position and may be a characteristic of the thresher's unique body and caudal fin morphology. Nonetheless, the uncoupling of red and white muscle strain remains a consistent character associated with fishes having a medially positioned red muscle.

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Mammal-like muscles power swimming in a cold-water shark

Nature, 2005

Effects of temperature on muscle contraction and powering movement are profound, outwardly obviou... more Effects of temperature on muscle contraction and powering movement are profound, outwardly obvious, and of great consequence to survival. To cope with the effects of environmental temperature fluctuations, endothermic birds and mammals maintain a relatively warm and constant body temperature, whereas most fishes and other vertebrates are ectothermic and conform to their thermal niche, compromising performance at colder temperatures. However, within the fishes the tunas and lamnid sharks deviate from the ectothermic strategy, maintaining elevated core body temperatures that presumably confer physiological advantages for their roles as fast and continuously swimming pelagic predators. Here we show that the salmon shark, a lamnid inhabiting cold, north Pacific waters, has become so specialized for endothermy that its red, aerobic, locomotor muscles, which power continuous swimming, seem mammal-like, functioning only within a markedly elevated temperature range (20-30°C). These muscles are ineffectual if exposed to the cool water temperatures, and when warmed even 10°C above ambient they still produce only 25-50% of the power produced at 26°C. In contrast, the white muscles, powering burst swimming, do not show such a marked thermal dependence and work well across a wide range of temperatures.

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Mammal-like muscles power swimming in a cold-water shark

Nature, 2005

Effects of temperature on muscle contraction and powering movement are profound, outwardly obviou... more Effects of temperature on muscle contraction and powering movement are profound, outwardly obvious, and of great consequence to survival 1,2 . To cope with the effects of environmental temperature fluctuations, endothermic birds and mammals maintain a relatively warm and constant body temperature, whereas most fishes and other vertebrates are ectothermic and conform to their thermal niche, compromising performance at colder temperatures 2,3 . However, within the fishes the tunas and lamnid sharks deviate from the ectothermic strategy, maintaining elevated core body temperatures 4,5 that presumably confer physiological advantages for their roles as fast and continuously swimming pelagic predators. Here we show that the salmon shark, a lamnid inhabiting cold, north Pacific waters, has become so specialized for endothermy that its red, aerobic, locomotor muscles, which power continuous swimming, seem mammal-like, functioning only within a markedly elevated temperature range (20-30 8C). These muscles are ineffectual if exposed to the cool water temperatures, and when warmed even 10 8C above ambient they still produce only 25-50% of the power produced at 26 8C. In contrast, the white muscles, powering burst swimming, do not show such a marked thermal dependence and work well across a wide range of temperatures.

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Intracranial self-stimulation recovers learning and memory capacity in basolateral amygdala-damaged rats

Neurobiology of Learning and Memory, 2010

We studied the capacity of post-training intracranial self-stimulation (SS) to reverse or amelior... more We studied the capacity of post-training intracranial self-stimulation (SS) to reverse or ameliorate learning and memory impairments caused by amygdala damage in rats. A first experiment showed that lesions of the basolateral amygdala (BLA) slow down acquisition of two-way active avoidance conditioning (2wAA). In a second experiment we observed that a post-training SS treatment administered immediately after each 2wAA conditioning session is able to completely reverse the disruptive effects of the BLA lesions, and the facilitative effect lasts for 10 days. A third experiment allowed us to differentiate the strong recuperative effects of the SS treatment from the slight effect caused by overtraining the same conditioning response. We concluded that SS is able to counteract the behavioral deficit induced by BLA damage, probably by activating alternative undamaged brain structures related to learning and memory, such as the hippocampus.

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Evidence for Temperature Elevation in the Aerobic Swimming Musculature of the Common Thresher Shark, Alopias vulpinus

Copeia, 2005

This paper reports on the in vivo temperature measurements for slow-twitch, red aerobic muscle (R... more This paper reports on the in vivo temperature measurements for slow-twitch, red aerobic muscle (RM) and fast twitch, white muscle (WM) of 24 Common Thresher Sharks, Alopias vulpinus, captured off the coast of Southern California. Mean (؎ SE) RM temperature elevation was 2.33 ؎ 0.30 C warmer than the ambient sea surface temperature (SST, 19.13 ؎ 0.22 C) and 2.25 ؎ 0.35 C warmer than the coldest WM temperature measured (19.23 ؎ 0.30 C). The maximum RM temperature elevation was 5.4 C above SST and up to 7.6 C above the WM. Nine Common Thresher Sharks exhibited RM temperatures that exceeded 3.0 C above SST. No significant relationship was found between fish total length and RM temperature elevation. Although there was individual variability in RM temperature elevation, this study documents that the Common Thresher Shark is capable of significantly elevating its RM temperature above that of the ambient conditions.

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Intracranial self-stimulation improves memory consolidation in rats with little training

Neurobiology of Learning and Memory, 2008

Post-training intracranial electrical self-stimulation can improve learning and memory consolidat... more Post-training intracranial electrical self-stimulation can improve learning and memory consolidation in rats. However, the molecular mechanisms involved are not known yet. Since previous paradigms of this kind of facilitation are relatively unsuitable to try a molecular approach, here we develop a single and short model of learning and memory facilitation by post-training self-stimulation that could make easier the research of its neural and molecular basis. Thus, three consecutive experiments were carried out to ascertain whether post-training self-stimulation is able to facilitate memory when learning consists of only a brief (5 trials) two-way active avoidance conditioning session. The results of Experiment 1 showed that it is actually possible, and that 48 h after the acquisition session is a very good time to observe the memory improvement. As a way to probe the retroactive effect of self-stimulation, in Experiment 2 we observed that the same self-stimulation treatment given to the subjects not post-training but 48 h before a single two-way active avoidance session does not improve the acquisition of conditioning. In Experiment 3, we showed that the SS facilitative effect observed 48 h after the acquisition session in Experiment 1 was still maintained one week later. We concluded that post-training intracranial self-stimulation can consistently improve memory consolidation even when little acquisition training is given to the animals in a single training session.

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The Use of Carbohydrate Profiles and Chemometrics in the Characterization of Natural Honeys of Identical Geographical Origin

Journal of Agricultural and Food Chemistry, 2005

Divergent locomotor muscle design among thresher sharks

Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2009

Download

Mammal-like muscles power swimming in a cold-water shark

Nature, 2005

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Mammal-like muscles power swimming in a cold-water shark

Nature, 2005

Effects of temperature on muscle contraction and powering movement are profound, outwardly obviou... more Effects of temperature on muscle contraction and powering movement are profound, outwardly obvious, and of great consequence to survival 1,2 . To cope with the effects of environmental temperature fluctuations, endothermic birds and mammals maintain a relatively warm and constant body temperature, whereas most fishes and other vertebrates are ectothermic and conform to their thermal niche, compromising performance at colder temperatures 2,3 . However, within the fishes the tunas and lamnid sharks deviate from the ectothermic strategy, maintaining elevated core body temperatures 4,5 that presumably confer physiological advantages for their roles as fast and continuously swimming pelagic predators. Here we show that the salmon shark, a lamnid inhabiting cold, north Pacific waters, has become so specialized for endothermy that its red, aerobic, locomotor muscles, which power continuous swimming, seem mammal-like, functioning only within a markedly elevated temperature range (20-30 8C). These muscles are ineffectual if exposed to the cool water temperatures, and when warmed even 10 8C above ambient they still produce only 25-50% of the power produced at 26 8C. In contrast, the white muscles, powering burst swimming, do not show such a marked thermal dependence and work well across a wide range of temperatures.

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Intracranial self-stimulation recovers learning and memory capacity in basolateral amygdala-damaged rats

Neurobiology of Learning and Memory, 2010

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Evidence for Temperature Elevation in the Aerobic Swimming Musculature of the Common Thresher Shark, Alopias vulpinus

Copeia, 2005

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Intracranial self-stimulation improves memory consolidation in rats with little training

Neurobiology of Learning and Memory, 2008

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