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Author Gulotta, M.; Gilmanshin, R.; Buscher, T.C.; Callender, R.H.; Dyer, R.B. openurl 
  Title Core formation in apomyoglobin: probing the upper reaches of the folding energy landscape Type Journal Article
  Year 2001 Publication Biochemistry Abbreviated Journal Biochemistry  
  Volume 40 Issue 17 Pages 5137-5143  
  Keywords (up) Animals; Apoproteins/*chemistry; Computer Simulation; Horses; Hydrogen-Ion Concentration; Kinetics; Models, Molecular; Myoglobin/*chemistry; *Protein Folding; Protein Structure, Secondary; Protein Structure, Tertiary; Spectrometry, Fluorescence/instrumentation/methods; Thermodynamics; Tryptophan/chemistry  
  Abstract An acid-destabilized form of apomyoglobin, the so-called E state, consists of a set of heterogeneous structures that are all characterized by a stable hydrophobic core composed of 30-40 residues at the intersection of the A, G, and H helices of the protein, with little other secondary structure and no other tertiary structure. Relaxation kinetics studies were carried out to characterize the dynamics of core melting and formation in this protein. The unfolding and/or refolding response is induced by a laser-induced temperature jump between the folded and unfolded forms of E, and structural changes are monitored using the infrared amide I' absorbance at 1648-1651 cm(-1) that reports on the formation of solvent-protected, native-like helix in the core and by fluorescence emission changes from apomyoglobin's Trp14, a measure of burial of the indole group of this residue. The fluorescence kinetics data are monoexponential with a relaxation time of 14 micros. However, infrared kinetics data are best fit to a biexponential function with relaxation times of 14 and 59 micros. These relaxation times are very fast, close to the limits placed on folding reactions by diffusion. The 14 micros relaxation time is weakly temperature dependent and thus represents a pathway that is energetically downhill. The appearance of this relaxation time in both the fluorescence and infrared measurements indicates that this folding event proceeds by a concomitant formation of compact secondary and tertiary structures. The 59 micros relaxation time is much more strongly temperature dependent and has no fluorescence counterpart, indicating an activated process with a large energy barrier wherein nonspecific hydrophobic interactions between helix A and the G and H helices cause some helix burial but Trp14 remains solvent exposed. These results are best fit by a multiple-pathway kinetic model when U collapses to form the various folded core structures of E. Thus, the results suggest very robust dynamics for core formation involving multiple folding pathways and provide significant insight into the primary processes of protein folding.  
  Address Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0006-2960 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:11318635 Approved no  
  Call Number Equine Behaviour @ team @ Serial 3789  
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Author Gulotta, M.; Rogatsky, E.; Callender, R.H.; Dyer, R.B. openurl 
  Title Primary folding dynamics of sperm whale apomyoglobin: core formation Type Journal Article
  Year 2003 Publication Biophysical Journal Abbreviated Journal Biophys J  
  Volume 84 Issue 3 Pages 1909-1918  
  Keywords (up) Animals; Apoproteins/*chemistry; Crystallography/*methods; Horses; Myocardium/chemistry; Myoglobin/*chemistry; Protein Conformation; *Protein Folding; Species Specificity; Structure-Activity Relationship; Temperature; Whales  
  Abstract The structure, thermodynamics, and kinetics of heat-induced unfolding of sperm whale apomyoglobin core formation have been studied. The most rudimentary core is formed at pH(*) 3.0 and up to 60 mM NaCl. Steady state for ultraviolet circular dichroism and fluorescence melting studies indicate that the core in this acid-destabilized state consists of a heterogeneous composition of structures of approximately 26 residues, two-thirds of the number involved for horse heart apomyoglobin under these conditions. Fluorescence temperature-jump relaxation studies show that there is only one process involved in Trp burial. This occurs in 20 micro s for a 7 degrees jump to 52 degrees C, which is close to the limits placed by diffusion on folding reactions. However, infrared temperature jump studies monitoring native helix burial are biexponential with times of 5 micro s and 56 micro s for a similar temperature jump. Both fluorescence and infrared fast phases are energetically favorable but the slow infrared absorbance phase is highly temperature-dependent, indicating a substantial enthalpic barrier for this process. The kinetics are best understood by a multiple-pathway kinetics model. The rapid phases likely represent direct burial of one or both of the Trp residues and parts of the G- and H-helices. We attribute the slow phase to burial and subsequent rearrangement of a misformed core or to a collapse having a high energy barrier wherein both Trps are solvent-exposed.  
  Address Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA. gulotta@aecom.yu.edu  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0006-3495 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:12609893 Approved no  
  Call Number Equine Behaviour @ team @ Serial 3783  
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Author Gilmanshin, R.; Callender, R.H.; Dyer, R.B. openurl 
  Title The core of apomyoglobin E-form folds at the diffusion limit Type Journal Article
  Year 1998 Publication Nature Structural Biology Abbreviated Journal Nat Struct Biol  
  Volume 5 Issue 5 Pages 363-365  
  Keywords (up) Animals; Apoproteins/*chemistry; Diffusion; Horses; Myoglobin/*chemistry; *Protein Folding; Spectroscopy, Fourier Transform Infrared; Temperature  
  Abstract The E-form of apomyoglobin has been characterized using infrared and fluorescence spectroscopies, revealing a compact core with native like contacts, most probably consisting of 15-20 residues of the A, G and H helices of apomyoglobin. Fast temperature-jump, time-resolved infrared measurements reveal that the core is formed within 96 micros at 46 degrees C, close to the diffusion limit for loop formation. Remarkably, the folding pathway of the E-form is such that the formation of a limited number of native-like contacts is not rate limiting, or that the contacts form on the same time scale expected for diffusion controlled loop formation.  
  Address  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1072-8368 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:9586997 Approved no  
  Call Number Equine Behaviour @ team @ Serial 3795  
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Author Abbruzzetti, S.; Crema, E.; Masino, L.; Vecli, A.; Viappiani, C.; Small, J.R.; Libertini, L.J.; Small, E.W. openurl 
  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 (up) 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  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0006-3495 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:10620304 Approved no  
  Call Number Equine Behaviour @ team @ Serial 3792  
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Author Permyakov, S.E.; Khokhlova, T.I.; Nazipova, A.A.; Zhadan, A.P.; Morozova-Roche, L.A.; Permyakov, E.A. doi  openurl
  Title Calcium-binding and temperature induced transitions in equine lysozyme: new insights from the pCa-temperature “phase diagrams” Type Journal Article
  Year 2006 Publication Proteins Abbreviated Journal Proteins  
  Volume 65 Issue 4 Pages 984-998  
  Keywords (up) Animals; Apoproteins/chemistry/metabolism; Binding Sites; Calcium/chemistry/*metabolism; Cattle; Edetic Acid/metabolism; Horses/metabolism; Hydrogen-Ion Concentration; Lactalbumin/chemistry/metabolism; Muramidase/*chemistry/*metabolism; Protein Denaturation; Spectrometry, Fluorescence; *Temperature; Thermodynamics; Tryptophan/chemistry/metabolism  
  Abstract The most universal approach to the studies of metal binding properties of single-site metal binding proteins, i.e., construction of a “phase diagram” in coordinates of free metal ion concentration-temperature, has been applied to equine lysozyme (EQL). EQL has one relatively strong calcium binding site and shows two thermal transitions, but only one of them is Ca(2+)-dependent. It has been found that the Ca(2+)-dependent behavior of the low temperature thermal transition (I) of EQL can be adequately described based upon the simplest four-states scheme of metal- and temperature-induced structural changes in a protein. All thermodynamic parameters of this scheme were determined experimentally and used for construction of the EQL phase diagram in the pCa-temperature space. Comparison of the phase diagram with that for alpha-lactalbumin (alpha-LA), a close homologue of lysozyme, allows visualization of the differences in thermodynamic behavior of the two proteins. The thermal stability of apo-EQL (transition I) closely resembles that for apo-alpha-LA (mid-temperature 25 degrees C), while the thermal stabilities of their Ca(2+)-bound forms are almost indistinguishable. The native state of EQL has three orders of magnitude lower affinity for Ca(2+) in comparison with alpha-LA while its thermally unfolded state (after the I transition) has about one order lower (K = 15M(-1)) affinity for calcium. Circular dichroism studies of the apo-lysozyme state after the first thermal transition show that it shares common features with the molten globule state of alpha-LA.  
  Address Institute for Biological Instrumentation of the Russian Academy of Sciences, Pushchino, Moscow region 142290, Russia  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1097-0134 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:17022083 Approved no  
  Call Number Serial 1858  
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Author Lin, Y.-L.; Moolenaar, H.; van Weeren, P.R.; van de Lest, C.H.A. doi  openurl
  Title Effect of microcurrent electrical tissue stimulation on equine tenocytes in culture Type Journal Article
  Year 2006 Publication American Journal of Veterinary Research Abbreviated Journal Am J Vet Res  
  Volume 67 Issue 2 Pages 271-276  
  Keywords (up) Animals; Apoptosis; Cell Proliferation; Cells, Cultured; Electric Stimulation; *Horses; Tendons/*cytology  
  Abstract OBJECTIVE: To determine effects of microcurrent electrical tissue stimulation (METS) on equine tenocytes cultured from the superficial digital flexor tendon (SDFT). SAMPLE POPULATION: SDFTs were collected from 20 horses at slaughter. PROCEDURE: Tenocytes were isolated following outgrowth from explants and grown in 48-well plates. Four methods of delivering current to the tenocytes with a METS device were tested. Once the optimal method was selected, current consisting of 0 (negative control), 0.05, 0.1, 0.5, 1.0, or 1.5 mA was applied to cells (8 wells/current intensity) once daily for 8 minutes. Cells were treated for 1, 2, or 3 days. Cell proliferation, DNA content, protein content, and apoptosis rate were determined. RESULTS: Application of microcurrent of moderate intensity increased cell proliferation and DNA content, with greater increases with multiple versus single application. Application of microcurrent of moderate intensity once or twice increased protein content, but application 3 times decreased protein content. Application of current a single time did not significantly alter apoptosis rate; however, application twice or 3 times resulted in significant increases in apoptosis rate, and there were significant linear (second order) correlations between current intensity and apoptosis rate when current was applied twice or 3 times. CONCLUSIONS AND CLINICAL RELEVANCE: Results of the present study indicate that microcurrent affects the behavior of equine tenocytes in culture, but that effects may be negative or positive depending on current intensity and number of applications. Therefore, results are far from conclusive with respect to the suitability of using METS to promote tendon healing in horses.  
  Address Department of Equine Sciences, Faculty of Veterinary Medicine, State University of Utrecht, Utrecht, The Netherlands  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0002-9645 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16454632 Approved no  
  Call Number Serial 1878  
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Author Houpt, K.A.; Northrup, N.; Wheatley, T.; Houpt, T.R. openurl 
  Title Thirst and salt appetite in horses treated with furosemide Type Journal Article
  Year 1991 Publication Journal of applied physiology (Bethesda, Md. : 1985) Abbreviated Journal J Appl Physiol  
  Volume 71 Issue 6 Pages 2380-2386  
  Keywords (up) Animals; Appetite/*drug effects; Blood Volume; Diuresis; Drinking/drug effects; Female; Furosemide/*pharmacology; Horses; Natriuresis; Sodium, Dietary/*administration & dosage; Thirst/*drug effects  
  Abstract When a preliminary experiment in sodium-replete ponies revealed an increase, but not a significant increase, in salt consumption after furosemide treatment, the experiment was repeated using sodium-deficient horses in which aldosterone levels might be expected to be elevated to test the hypothesis that a background of aldosterone is necessary for salt appetite. Ten Standardbred mares were injected intravenously with furosemide or an equivalent volume of 0.9% sodium chloride as a control to test the effect of furosemide on their salt appetite and blood constituents. Sodium intake and sodium loss in urine, as well as water intake and urine output, were measured and compared to determine accuracy of compensation for natriuresis and diuresis. Plasma protein and packed cell volume showed significant increases in response to furosemide treatment (F = 29.31, P less than 0.001 and F = 11.20, P less than 0.001, respectively). There were no significant changes in plasma sodium concentration or osmolality in response to the treatment (P greater than 0.05). The furosemide-treated horses consumed 126 +/- 14.8 g salt, significantly more than when they were given the control injection (94.5 +/- 9.8 g; t = 2.22, P = 0.05). In response to furosemide, horses lost 962 +/- 79.7 and consumed 2,170 +/- 5 meq sodium; however, compared with control, they lost 955 meq more sodium and ingested only 570 meq more sodium, so they were undercompensating for natriuresis. The furosemide-treated horses drank 9.6 +/- 0.8 kg of water, significantly more than when they received the control injection (6.4 +/- 0.8 kg; t = 6.9, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)  
  Address Department of Physiology, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853-6401  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 8750-7587 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:1778936 Approved no  
  Call Number refbase @ user @ Serial 38  
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Author Houpt, T.R. openurl 
  Title The physiological determination of meal size in pigs Type Journal Article
  Year 1985 Publication The Proceedings of the Nutrition Society Abbreviated Journal Proc Nutr Soc  
  Volume 44 Issue 2 Pages 323-330  
  Keywords (up) Animals; Appetite/physiology; Drinking; Duodenum/physiology; *Eating; Energy Intake; Food; Horses/physiology; Milk; Osmolar Concentration; Receptors, Cell Surface/physiology; Receptors, Cholecystokinin; Swine/*physiology; Time Factors  
  Abstract  
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  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0029-6651 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:2996010 Approved no  
  Call Number refbase @ user @ Serial 53  
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Author Krcmar, S.; Mikuska, A.; Merdic, E. openurl 
  Title Response of Tabanidae (Diptera) to different natural attractants Type Journal Article
  Year 2006 Publication Journal of Vector Ecology : Journal of the Society for Vector Ecology Abbreviated Journal J Vector Ecol  
  Volume 31 Issue 2 Pages 262-265  
  Keywords (up) Animals; Appetitive Behavior/*physiology; Cattle/urine; Diptera/*physiology; Female; Horses/urine; Insect Control/methods; Sheep/urine; Swine/urine; Urine/*physiology  
  Abstract The response of female tabanids to natural attractants was studied in the Monjoros Forest along the Nature Park Kopacki rit in eastern Croatia. Tabanids were caught in canopy traps baited with either aged cow, horse, sheep, or pig urine and also in unbaited traps. Tabanids were collected in a significantly higher numbers in traps baited with natural attractants compared to unbaited traps. The number of females of Tabanus bromius, Tabanus maculicornis, Tabanus tergestinus, and Hybomitra bimaculata collected from canopy traps baited with cow urine and traps baited with other natural attractants differed significantly. Females of Haematopota pluvialis were also collected more frequently in canopy traps baited with aged cow urine than in those with aged horse urine, but this difference was not significant. However, the number of females of Haematopota pluvialis collected from canopy traps baited with other natural attractants (sheep and pig urine) differed significantly when compared with aged cow urine baited traps. Canopy traps baited with aged cow urine collected significantly more Tabanus sudeticus than did traps baited with aged pig urine. Finally, the aged cow urine baited canopy traps collected 51 times more tabanids than unbaited traps, while aged horse, aged sheep, and aged pig urine baited traps collected 36, 30, and 22 times as many tabanids, respectively, than unbaited traps.  
  Address Department of Biology, JJ Strossmayer University, Lj. Gaja 6, HR-31000 Osijek, Croatia  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1081-1710 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:17249343 Approved no  
  Call Number Serial 1836  
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Author Hanggi, E.B.; Ingersoll, J.F.; Waggoner, T.L. doi  openurl
  Title Color vision in horses (Equus caballus): deficiencies identified using a pseudoisochromatic plate test Type Journal Article
  Year 2007 Publication Journal of Comparative Psychology Abbreviated Journal J. Comp. Psychol.  
  Volume 121 Issue 1 Pages 65-72  
  Keywords (up) Animals; Appetitive Behavior; *Color Perception; Color Perception Tests/veterinary; *Discrimination Learning; Female; Horses/*psychology; Male; Sensitivity and Specificity  
  Abstract In the past, equine color vision was tested with stimuli composed either of painted cards or photographic slides or through physiological testing using electroretinogram flicker photometry. Some studies produced similar results, but others did not, demonstrating that there was not yet a definitive answer regarding color vision in horses (Equus caballus). In this study, a pseudoisochromatic plate test--which is highly effective in testing color vision both in small children and in adult humans--was used for the first time on a nonhuman animal. Stimuli consisted of different colored dotted circles set against backgrounds of varying dots. The coloration of the circles corresponded to the visual capabilities of different types of color deficiencies (anomalous trichromacy and dichromacy). Four horses were tested on a 2-choice discrimination task. All horses successfully reached criterion for gray circles and demonstration circles. None of the horses were able to discriminate the protan-deutan plate or the individual protan or deutan plates. However, all were able to discriminate the tritan plate. The results suggest that horses are dichromats with color vision capabilities similar to those of humans with red-green color deficiencies.  
  Address Equine Research Foundation, Aptos, CA 95001, USA. EquiResF@aol.com  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0735-7036 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:17324076 Approved no  
  Call Number refbase @ user @ ; Equine Behaviour @ team @ room B 3.029 Serial 1972  
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