Records |
Author |
Marc, M.; Parvizi, N.; Ellendorff, F.; Kallweit, E.; Elsaesser, F. |
Title |
Plasma cortisol and ACTH concentrations in the warmblood horse in response to a standardized treadmill exercise test as physiological markers for evaluation of training status |
Type |
Journal Article |
Year |
2000 |
Publication |
Journal of Animal Science |
Abbreviated Journal |
J. Anim Sci. |
Volume |
78 |
Issue |
7 |
Pages |
1936-1946 |
Keywords |
Adrenocorticotropic Hormone/*blood/diagnostic use; Animals; Catheterization/veterinary; Exercise Test; Horses/*blood; Hydrocortisone/*blood; Male; *Physical Conditioning, Animal |
Abstract |
Reliable physiological markers for performance evaluation in sport horses are missing. To determine the diagnostic value of plasma ACTH and cortisol measurements in the warmblood horse, 10 initially 3-yr-old geldings of the Hannovarian breed were either exposed to a training schedule or served as controls. During experimental Phase 1, horses were group-housed, and half of the horses were trained for 20 wk on a high-speed treadmill. During Phase 2, groups were switched and one group was trained for 10 wk as during Phase 1, whereas the control group was confined to boxes. During Phase 3 horses were initially schooled for riding. Thereafter, all horses were regularly schooled for dressage and jumping, and half of the horses received an additional endurance training for 24 wk. During all phases horses were exposed at regular intervals to various standardized treadmill exercise tests. During and after the tests frequent blood samples were taken from an indwelling jugular catheter for determination of ACTH and cortisol. Treadmill exercise increased both hormones. Maximum ACTH concentrations were recorded at the end of exercise, and maximum cortisol levels were recorded 20 to 30 min later. Except for one test there were no differences in ACTH levels between trained horses and controls. There was no significant effect of training on the cortisol response (net increase) to treadmill exercise in any of the tests during Phase 1. During Phase 2 higher cortisol responses were recorded in controls than in trained horses (P < .05) after 10 wk of training (controls confined to boxes). During Phase 3 plasma cortisol responses were also higher in controls than in trained horses (P < .05 after 6, 18, and 24, P < or = .07 after 12 wk of training) when the inclination of the treadmill was 5%, but not at 3%. There was no overlap in net cortisol responses at 30 min between trained and untrained horses. An ACTH application after 24 wk of training resulted in higher cortisol responses in controls than in trained horses (P < or = .05), without any overlap between the groups at 30 min after ACTH. Plasma cortisol responses to either treadmill exercise or ACTH injection may be a reliable physiological marker for performance evaluation. Prerequisites are sufficient differences in training status and sufficient intensity of exercise test conditions. |
Address |
Institute of Animal Science and Animal Behaviour, Federal Agricultural Research Center (FAL) Mariensee, Neustadt, Germany |
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0021-8812 |
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PMID:10907837 |
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Equine Behaviour @ team @ |
Serial |
3732 |
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Author |
Hagen, S.J.; Eaton, W.A. |
Title |
Two-state expansion and collapse of a polypeptide |
Type |
Journal Article |
Year |
2000 |
Publication |
Journal of Molecular Biology |
Abbreviated Journal |
J Mol Biol |
Volume |
301 |
Issue |
4 |
Pages |
1019-1027 |
Keywords |
Animals; Computer Simulation; Cytochrome c Group/*chemistry/*metabolism; Horses; Kinetics; Lasers; Models, Chemical; Peptides/*chemistry/*metabolism; Protein Conformation; Protein Denaturation; *Protein Folding; Spectrometry, Fluorescence; Temperature; Thermodynamics |
Abstract |
The initial phase of folding for many proteins is presumed to be the collapse of the polypeptide chain from expanded to compact, but still denatured, conformations. Theory and simulations suggest that this collapse may be a two-state transition, characterized by barrier-crossing kinetics, while the collapse of homopolymers is continuous and multi-phasic. We have used a laser temperature-jump with fluorescence spectroscopy to measure the complete time-course of the collapse of denatured cytochrome c with nanosecond time resolution. We find the process to be exponential in time and thermally activated, with an apparent activation energy approximately 9 k(B)T (after correction for solvent viscosity). These results indicate that polypeptide collapse is kinetically a two-state transition. Because of the observed free energy barrier, the time scale of polypeptide collapse is dramatically slower than is predicted by Langevin models for homopolymer collapse. |
Address |
Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Building 5, Bethesda, MD, 20892-0520, USA |
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0022-2836 |
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PMID:10966803 |
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Equine Behaviour @ team @ |
Serial |
3790 |
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Author |
Abbruzzetti, S.; Crema, E.; Masino, L.; Vecli, A.; Viappiani, C.; Small, J.R.; Libertini, L.J.; Small, E.W. |
Title |
Fast events in protein folding: structural volume changes accompanying the early events in the N-->I transition of apomyoglobin induced by ultrafast pH jump |
Type |
Journal Article |
Year |
2000 |
Publication |
Biophysical Journal |
Abbreviated Journal |
Biophys J |
Volume |
78 |
Issue |
1 |
Pages |
405-415 |
Keywords |
Animals; Apoproteins/*chemistry; Horses; *Hydrogen-Ion Concentration; Kinetics; Models, Molecular; Myoglobin/*chemistry; Protein Conformation; *Protein Folding; Protein Structure, Secondary; Spectrometry, Fluorescence |
Abstract |
Ultrafast, laser-induced pH jump with time-resolved photoacoustic detection has been used to investigate the early protonation steps leading to the formation of the compact acid intermediate (I) of apomyoglobin (ApoMb). When ApoMb is in its native state (N) at pH 7.0, rapid acidification induced by a laser pulse leads to two parallel protonation processes. One reaction can be attributed to the binding of protons to the imidazole rings of His24 and His119. Reaction with imidazole leads to an unusually large contraction of -82 +/- 3 ml/mol, an enthalpy change of 8 +/- 1 kcal/mol, and an apparent bimolecular rate constant of (0.77 +/- 0.03) x 10(10) M(-1) s(-1). Our experiments evidence a rate-limiting step for this process at high ApoMb concentrations, characterized by a value of (0. 60 +/- 0.07) x 10(6) s(-1). The second protonation reaction at pH 7. 0 can be attributed to neutralization of carboxylate groups and is accompanied by an apparent expansion of 3.4 +/- 0.2 ml/mol, occurring with an apparent bimolecular rate constant of (1.25 +/- 0.02) x 10(11) M(-1) s(-1), and a reaction enthalpy of about 2 kcal/mol. The activation energy for the processes associated with the protonation of His24 and His119 is 16.2 +/- 0.9 kcal/mol, whereas that for the neutralization of carboxylates is 9.2 +/- 0.9 kcal/mol. At pH 4.5 ApoMb is in a partially unfolded state (I) and rapid acidification experiments evidence only the process assigned to carboxylate protonation. The unusually large contraction and the high energetic barrier observed at pH 7.0 for the protonation of the His residues suggests that the formation of the compact acid intermediate involves a rate-limiting step after protonation. |
Address |
Dipartimento di Fisica, Universita di Parma, 43100 Parma, Italia |
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0006-3495 |
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PMID:10620304 |
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no |
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Equine Behaviour @ team @ |
Serial |
3792 |
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Author |
Pierce, M.M.; Nall, B.T. |
Title |
Coupled kinetic traps in cytochrome c folding: His-heme misligation and proline isomerization |
Type |
Journal Article |
Year |
2000 |
Publication |
Journal of Molecular Biology |
Abbreviated Journal |
J Mol Biol |
Volume |
298 |
Issue |
5 |
Pages |
955-969 |
Keywords |
Amino Acid Sequence; Amino Acid Substitution/genetics; Binding Sites; Cytochrome c Group/*chemistry/genetics/*metabolism; *Cytochromes c; Enzyme Stability/drug effects; Fluorescence; Guanidine/pharmacology; Heme/*metabolism; Histidine/genetics/*metabolism; Hydrogen-Ion Concentration; Isomerism; Kinetics; Models, Molecular; Molecular Sequence Data; Mutation/genetics; Proline/*chemistry/metabolism; Protein Conformation/drug effects; Protein Denaturation/drug effects; *Protein Folding; Protein Renaturation; Saccharomyces cerevisiae/enzymology/genetics; Sequence Alignment; Thermodynamics |
Abstract |
The effect of His-heme misligation on folding has been investigated for a triple mutant of yeast iso-2 cytochrome c (N26H,H33N,H39K iso-2). The variant contains a single misligating His residue at position 26, a location at which His residues are found in several cytochrome c homologues, including horse, tuna, and yeast iso-1. The amplitude for fast phase folding exhibits a strong initial pH dependence. For GdnHCl unfolded protein at an initial pH<5, the observed refolding at final pH 6 is dominated by a fast phase (tau(2f)=20 ms, alpha(2f)=90 %) that represents folding in the absence of misligation. For unfolded protein at initial pH 6, folding at final pH 6 occurs in a fast phase of reduced amplitude (alpha(2f) approximately 20 %) but the same rate (tau(2f)=20 ms), and in two slower phases (tau(m)=6-8 seconds, alpha(m) approximately 45 %; and tau(1b)=16-20 seconds, alpha(1b) approximately 35 %). Double jump experiments show that the initial pH dependence of the folding amplitudes results from a slow pH-dependent equilibrium between fast and slow folding species present in the unfolded protein. The slow equilibrium arises from coupling of the His protonation equilibrium to His-heme misligation and proline isomerization. Specifically, Pro25 is predominantly in trans in the unligated low-pH unfolded protein, but is constrained in a non-native cis isomerization state by His26-heme misligation near neutral pH. Refolding from the misligated unfolded form proceeds slowly due to the large energetic barrier required for proline isomerization and displacement of the misligated His26-heme ligand. |
Address |
Center for Biomolecular Structure, Department of Biochemistry, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA |
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0022-2836 |
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PMID:10801361 |
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refbase @ user @ |
Serial |
3853 |
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Author |
Emery, N.J. |
Title |
The eyes have it: the neuroethology, function and evolution of social gaze |
Type |
Journal Article |
Year |
2000 |
Publication |
Neuroscience and Biobehavioral Reviews |
Abbreviated Journal |
Neurosci Biobehav Rev |
Volume |
24 |
Issue |
6 |
Pages |
581-604 |
Keywords |
Animals; *Eye; Fixation, Ocular; Humans; *Social Behavior |
Abstract |
Gaze is an important component of social interaction. The function, evolution and neurobiology of gaze processing are therefore of interest to a number of researchers. This review discusses the evolutionary role of social gaze in vertebrates (focusing on primates), and a hypothesis that this role has changed substantially for primates compared to other animals. This change may have been driven by morphological changes to the face and eyes of primates, limitations in the facial anatomy of other vertebrates, changes in the ecology of the environment in which primates live, and a necessity to communicate information about the environment, emotional and mental states. The eyes represent different levels of signal value depending on the status, disposition and emotional state of the sender and receiver of such signals. There are regions in the monkey and human brain which contain neurons that respond selectively to faces, bodies and eye gaze. The ability to follow another individual's gaze direction is affected in individuals with autism and other psychopathological disorders, and after particular localized brain lesions. The hypothesis that gaze following is “hard-wired” in the brain, and may be localized within a circuit linking the superior temporal sulcus, amygdala and orbitofrontal cortex is discussed. |
Address |
Center for Neuroscience, Department of Psychiatry & California Regional Primate Research Center, University of California, Davis, CA 95616, USA. njemery@ucdavis.edu |
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0149-7634 |
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PMID:10940436 |
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no |
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refbase @ user @ |
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3996 |
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Author |
Madigan, J.E.; Whittemore, J. |
Title |
The role of the equine practitioner in disasters |
Type |
Journal Article |
Year |
2000 |
Publication |
Journal of the American Veterinary Medical Association |
Abbreviated Journal |
J Am Vet Med Assoc |
Volume |
216 |
Issue |
8 |
Pages |
1238-1239 |
Keywords |
*Animal Husbandry/education; *Animal Welfare; Animals; Disaster Planning; *Horses; *Natural Disasters; United States; *Veterinary Medicine |
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Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis 95616, USA |
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0003-1488 |
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PMID:10767959 |
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no |
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Equine Behaviour @ team @ |
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4055 |
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Author |
Weiss, A.; King, J.E.; Figueredo, A.J. |
Title |
The heritability of personality factors in chimpanzees (Pan troglodytes) |
Type |
Journal Article |
Year |
2000 |
Publication |
Behavior Genetics |
Abbreviated Journal |
Behav Genet |
Volume |
30 |
Issue |
3 |
Pages |
213-221 |
Keywords |
Animals; Female; Humans; Male; Models, Genetic; Pan troglodytes/*genetics; Personality/*genetics; Social Environment |
Abstract |
Human personality and behavior genetic studies have resulted in a growing consensus that five heritable factors account for most variance in human personality. Prior research showed that chimpanzee personality is composed of a dominance-related factor and five human-like factors--Surgency, Dependability, Emotional Stability, Agreeableness, and Openness. Genetic, shared zoo, and nonshared environmental variance components of the six factors were estimated by regressing squared phenotypic differences of all possible pairs of chimpanzees onto 1 – Rij, where Rij equals the degree of relationship and a variable indicating whether the pair was housed in the same zoo. Dominance showed significant narrow-sense heritability. Shared zoo effects accounted for only a negligible proportion of the variance for all factors. |
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Department of Psychology, University of Arizona, Tucson 85721, USA. aweiss@u.arizona.edu |
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0001-8244 |
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PMID:11105395 |
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Equine Behaviour @ team @ |
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4143 |
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Mrabet, O.; Es-Salah, Z.; Telhiq, A.; Aubert, A.; Liege, S.; Choulli, K.; Neveu, P.J. |
Title |
Influence of gender and behavioural lateralisation on two exploratory models of anxiety in C3H mice |
Type |
Journal Article |
Year |
2000 |
Publication |
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Abbreviated Journal |
Behav Processes |
Volume |
52 |
Issue |
1 |
Pages |
35-42 |
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Abstract |
Behavioural lateralisation, which has been postulated to be an individual personality trait, is related to the activity of various physiological systems including the immune system. As lateralisation has been related to anxiety, which is known to influence immune reactivity, it can be hypothesized that the relation between lateralisation and immune reactivity involves individual behavioural patterns as they appear in exploratory-based anxiety models. In order to answer this question, a behavioural investigation focussing on exploratory activity was undertaken in male and female C3H mice previously selected for their paw preference. The observations were performed using two generic paradigms: elevated plus-maze and open field. Exploratory behaviour in the open field, but not in the plus-maze, was influenced by the interactive effect of gender and behavioural lateralisation. A significant difference between male and female mice was found in left-pawed but not in right-pawed nor ambidextrous animals, left-pawed female mice displaying the less exploratory behaviours. These results provide a first evidence of inter-individual variations in exploratory behaviours involving interaction between gender and lateralisation. |
Address |
U.F.R. des Sciences Biologiques et Pharmaceutiques, Departement de Biologie, Faculte des Sciences, Universite Ibn Tofail, Kenitra, Morocco |
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0376-6357 |
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PMID:11011107 |
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Equine Behaviour @ team @ |
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4149 |
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Author |
Rogers, L.J. |
Title |
Evolution of hemispheric specialization: advantages and disadvantages |
Type |
Journal Article |
Year |
2000 |
Publication |
Brain and Language |
Abbreviated Journal |
Brain Lang |
Volume |
73 |
Issue |
2 |
Pages |
236-253 |
Keywords |
Aggression/psychology; Animals; Behavior, Animal/physiology; Brain/*physiology; Chickens/physiology; *Evolution; Feeding Behavior/physiology; Functional Laterality/*physiology; Visual Fields/physiology; Visual Perception/physiology |
Abstract |
Lateralization of the brain appeared early in evolution and many of its features appear to have been retained, possibly even in humans. We now have a considerable amount of information on the different forms of lateralization in a number of species, and the commonalities of these are discussed, but there has been relatively little investigation of the advantages of being lateralized. This article reports new findings on the differences between lateralized and nonlateralized chicks. The lateralized chicks were exposed to light for 24 h on day 19 of incubation, a treatment known to lead to lateralization of a number of visually guided responses, and the nonlateralized chicks were incubated in the dark. When they were feeding, the lateralized chicks were found to detect a stimulus resembling a raptor with shorter latency than nonlateralized chicks. This difference was not a nonspecific effect caused by the light-exposed chicks being more distressed by the stimulus. Instead, it appears to be a genuine advantage conferred by having a lateralized brain. It is suggested that having a lateralized brain allows dual attention to the tasks of feeding (right eye and left hemisphere) and vigilance for predators (left eye and right hemisphere). Nonlateralized chicks appear to perform these dual tasks less efficiently than lateralized ones. Reference is made to other species in discussing these results. |
Address |
Division of Zoology, University of New England, Armidale, New South Wales, Australia. lrogers@metz.une.edu.au |
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0093-934X |
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PMID:10856176 |
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Equine Behaviour @ team @ |
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4621 |
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Author |
Nicol, C.J |
Title |
Equine Stereotypies. In: Houpt K.A. (Ed.), |
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Book Chapter |
Year |
2000 |
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Recent Advances in Companion Animal Behavior Problems |
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International Veterinary Information Service |
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refbase @ user @ |
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477 |
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