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Author Miksovska, J.; Larsen, R.W.
Title Photothermal studies of pH induced unfolding of apomyoglobin Type Journal Article
Year 2003 Publication Journal of Protein Chemistry Abbreviated Journal J Protein Chem
Volume (up) 22 Issue 4 Pages 387-394
Keywords Acoustics; Animals; Apoproteins/*chemistry/metabolism; Circular Dichroism; Horses; Myocardium/chemistry; Myoglobin/*chemistry/metabolism; Photolysis; Protein Conformation/radiation effects; Protein Denaturation/radiation effects; *Protein Folding; Temperature; Thermodynamics
Abstract Conformational dynamic and enthalpy changes associated with pH induced unfolding of apomyoglobin were studied using photoacoustic calorimetry and photothermal beam deflection methods. The transition between the native state and the I intermediate was induced by a nanosecond pH jump from o-nitrobenzaldehyde photolysis. Deconvolution of photoacoustic waves indicates two kinetic processes. The fast phase (T < 50 ns) is characterized by a volume expansion of 8.8 ml mol(-1). This process is followed by a volume contraction of about -22 ml mol(-1) (tau approximately 500 ns). Photothermal beam deflection measurements do not reveal any volume changes on the time scale between approximately 100 micros and 5 ms. We associate the volume contraction with structural changes occurring during the transition between the native state and the I intermediate. The lack of any processes on the ms time scale may indicate the absence of structural events involving larger conformational changes of apomyoglobin after the pH jump.
Address Department of Chemistry, University of South Florida, Tampa, Florida 33620, 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 0277-8033 ISBN Medium
Area Expedition Conference
Notes PMID:13678303 Approved no
Call Number Equine Behaviour @ team @ Serial 3780
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Author Marlin, D.J.; Schroter, R.C.; White, S.L.; Maykuth, P.; Matthesen, G.; Mills, P.C.; Waran, N.; Harris, P.
Title Recovery from transport and acclimatisation of competition horses in a hot humid environment Type Journal Article
Year 2001 Publication Equine Veterinary Journal Abbreviated Journal Equine Vet J
Volume (up) 33 Issue 4 Pages 371-379
Keywords Acclimatization/*physiology; Animals; Body Temperature; Body Weight; Breeding; Feeding Behavior; Female; Heart Rate; Heat; Heat Stroke/prevention & control/veterinary; Horse Diseases/prevention & control; Horses/*physiology; Humidity; Male; Respiration; Sports; *Transportation; Tropical Climate
Abstract The aims of the present field-based study were to investigate changes in fit horses undergoing acclimatisation to a hot humid environment and to provide data on which to base recommendations for safe transport and acclimatisation. Six horses (age 7-12 years) were flown from Europe to Atlanta and underwent a 16 day period of acclimatisation. Exercise conditions during acclimatisation (wet bulb globe temperature index 27.6+/-0.0 [mean +/- s.e.]) were more thermally stressful compared with the European climate from which the horses had come (22.0+/-1.8, P<0.001). Following the flight, weight loss was 4.1+/-0.8% bodyweight and took around 7 days to recover. Water intake during the day was significantly increased (P<0.05) compared with night during acclimatisation. Daily mean exercise duration was 72+/-12 min and the majority of work was performed with a heart rate below 120 beats/min. Respiratory rate (fR) was increased (P<0.05) throughout acclimatisation compared with in Europe, but resting morning (AM) and evening (PM) rectal temperature (TREC), heart rate (fC) and plasma volume were unchanged. White blood cell (WBC) count was significantly increased at AM compared with in Europe on Days 4 and 10 of acclimatisation (P<0.01), but was not different by Day 16. In conclusion, horses exposed to hot humid environmental conditions without prior acclimatisation are able to accommodate these stresses and, with appropriate management, remain fit and clinically healthy, without significant risk of heat illness or heat-related disorders, provided they are allowed sufficient time to recover from transport, acclimatisation is undertaken gradually and they are monitored appropriately.
Address Centre for Equine Studies, Animal Health Trust, Newmarket, Suffolk, UK
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 0425-1644 ISBN Medium
Area Expedition Conference
Notes PMID:11469770 Approved no
Call Number refbase @ user @ Serial 1917
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Author Morgan, K.; Funkquist, P.; Nyman, G.
Title The effect of coat clipping on thermoregulation during intense exercise in trotters Type Journal Article
Year 2002 Publication Equine Veterinary Journal Abbreviated Journal Equine Veterinary Journal
Volume (up) 34 Issue S34 Pages 564-567
Keywords horse; thermoregulation; heat loss; recovery; blood temperature; oxygen uptake
Abstract Summary The aim of this study was to study the physiological, especially thermoregulatory, responses during intense exercise in the clipped horse compared to the horse with winter coat. Six Standardbred trotters were studied before and after clipping. They performed an inclined incremental high intensity treadmill exercise test and were monitored during recovery. The clipped horse differed significantly (ANOVA) during exercise as compare to coated: less increase in central venous blood temperature, higher skin surface temperature, greater difference skin to ambient temperature and higher rate of nonevaporative heat loss. The clipped horse had significantly lower total cutaneous evaporative heat loss from walk to end of peak exercise and a shorter time for recovery for the respiratory rate using a paired t test. The clipped horse showed a tendency (P = 0.059) to decreased oxygen uptake during the stepwise increase in workload. We concluded that the clipped horse experienced less strain on the thermoregulatory system due to an enhanced heat loss. Some clipped horses in the study showed a more efficient power output; future studies with emphasis on respiration and oxygen demand are needed to explain this.
Address
Corporate Author Thesis
Publisher American Medical Association (AMA) Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0425-1644 ISBN Medium
Area Expedition Conference
Notes doi: 10.1111/j.2042-3306.2002.tb05484.x Approved no
Call Number Equine Behaviour @ team @ Serial 6614
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Author Pritchard, J.C.; Barr, A.R.S.; Whay, H.R.
Title Validity of a behavioural measure of heat stress and a skin tent test for dehydration in working horses and donkeys Type
Year 2006 Publication Equine veterinary journal Abbreviated Journal Equine Vet J
Volume (up) 38 Issue 5 Pages 433-438
Keywords Age Factors; Animal Welfare; Animals; Behavior, Animal/physiology; Body Temperature/*physiology; Body Weight/physiology; Case-Control Studies; Dehydration/diagnosis/pathology/*veterinary; Drinking; *Equidae; Female; Heat Stress Disorders/diagnosis/physiopathology/*veterinary; Horse Diseases/*diagnosis/pathology; Horses; Hypovolemia/diagnosis/physiopathology/veterinary; Male; Osmolar Concentration; Pakistan; Respiration; Skin/*pathology; Species Specificity; Work
Abstract REASONS FOR PERFORMING STUDY: Dehydration and heat stress are serious welfare issues for equids working in developing countries. There is a lack of any standardised method or validated interpretation of the skin tent test in horses and donkeys. Owners of dehydrated and heat-stressed animals often depend on veterinary examination for identification of these conditions, leading to delays in treatment and unnecessary reliance on external sources to effect welfare improvement. OBJECTIVES: To validate a standardised skin tent test for dehydration and a behavioural measure of heat stress in working equids; and to examine the effect of heat stress and dehydration on tripping and staggering behaviour. METHODS: The study was carried out on 130 working horses and donkeys in Pakistan. Associations between skin tent and blood parameters (packed cell volume [PCV], serum total protein [TP], serum osmolality), clinical parameters, resting and drinking behaviour were examined. Heat stress behaviour (increased respiratory rate and depth, head nodding, flared nostrils, apathy) was observed in conjunction with rectal temperature. Tripping and staggering were assessed using a simple obstacle course. RESULTS: In both species, heat stress behaviour was significantly associated with increased rectal temperature (P<0.001). A positive skin tent test was not significantly associated with PCV or TP, although in donkeys it was significantly associated with lower serum osmolality (P<0.001). More animals age >15 years had a positive skin tent than those in younger age groups (P = 0.037). Very thin horses were more likely to have a positive skin tent than those in thin or moderate condition (P = 0.028). There was no significant correlation between skin tent and tripping or staggering in either species. CONCLUSIONS AND POTENTIAL RELEVANCE: Heat stress behaviour is related to increased body temperature in working horses and donkeys. Owners may use this to make judgements regarding rest and cooling, precluding the need to seek veterinary attention. The skin tent test for dehydration used in this study did not show a significant relationship with PCV or TP. However, the use of blood parameters to validate the skin tent test may be confounded by anaemia, hypoproteinaemia or electrolyte depletion. Alternative methods are needed to confirm or refute the validity of the skin tent test in working equids.
Address Department of Clinical Veterinary Science, University of Bristol, Langford, UK
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 0425-1644 ISBN Medium
Area Expedition Conference
Notes PMID:16986604 Approved no
Call Number Serial 1784
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Author Duncan, I.J.H.; Widowski, T.M.; Malleau, A.E.; Lindberg, A.C.; Petherick, J.C.
Title External factors and causation of dustbathing in domestic hens Type Journal Article
Year 1998 Publication Behavioural Processes Abbreviated Journal Behav. Process.
Volume (up) 43 Issue 2 Pages 219-228
Keywords Dustbathing; Illumination; Laying hens; Radiant heat; Social facilitation; Temperature
Abstract Dustbathing is known to be motivated by complex interactions between internal factors which build up over time and external factors, such as the sight of a dusty substrate. In this study, the effects of other external factors were investigated. Environmental temperature was shown to be important; frequencies of dustbathing were greater when hens were held at 22 than at 10[degree sign]C (P<0.01). In a second experiment, a radiant heat source or a radiant heat+light source, balanced to give the same radiant heat, resulted in more dustbathing behaviour during a 1-h stimulus period than during the same period with no stimulus (P<0.05). Components of dustbathing were increased more by the heat+light stimulus than by the heat stimulus alone (P<0.03). In a third experiment, the amount of dustbathing performed by individual hens in cages with dustbaths was increased by the presence of a group of hens dustbathing in an adjoining pen with a dustbath compared with the amount occurring when the hens were absent from the pen.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 3607
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Author Crowell-Davis, S.L.; Houpt, K.A.; Carnevale, J.
Title Feeding and drinking behavior of mares and foals with free access to pasture and water Type Journal Article
Year 1985 Publication Journal of animal science Abbreviated Journal J. Anim Sci.
Volume (up) 60 Issue 4 Pages 883-889
Keywords Animals; *Drinking Behavior; *Feeding Behavior; Female; Horses/*physiology; Male; Poaceae; Seasons; Temperature; Time Factors
Abstract The feeding and drinking behavior of 11 mares and 15 foals living on pasture with free access to water was recorded during 2,340 15-min focal samples taken over 2 yr. Lactating mares on pasture spent about 70% of the day feeding. Foals began feeding on their first day of life. As they grew older, they spent progressively more time feeding, but still spent only 47 +/- 6% of the time feeding by 21 wk of age. Foals fed primarily during the early morning and evening. While grass formed the major proportion of the diet of both foals and mares, they also ate clay, humus, feces, bark, leaves and twigs. Almost all feeding by foals was done while their mothers were feeding. Movement to water sources was frequently, but not invariably, carried out by an entire herd. Frequency (P = .005) but not duration (P greater than .05) of drinking bouts by mares increased as the temperature increased. Frequency was greatest at 30 to 35 C, at which temperature mares drank once every 1.8 h. Frequency of drinking varied with the time of day (P less than .01), being rarest during the early morning (0500 to 0900 h eastern daylight time) and most frequent during the afternoon (1300 to 1700 h). Drinking by foals was very rare. The youngest age at which a foal was observed to drink was 3 wk, and 8 of 15 foals were never observed to drink before weaning.
Address
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 0021-8812 ISBN Medium
Area Expedition Conference
Notes PMID:3988655 Approved no
Call Number refbase @ user @ Serial 54
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Author Balakrishnan, G.; Hu, Y.; Spiro, T.G.
Title Temperature-jump apparatus with Raman detection based on a solid-state tunable (1.80-2.05 microm) kHz optical parametric oscillator laser Type Journal Article
Year 2006 Publication Applied Spectroscopy Abbreviated Journal Appl Spectrosc
Volume (up) 60 Issue 4 Pages 347-351
Keywords Animals; Cytochromes c/analysis; Horses; Lasers; Myoglobin/metabolism; Spectrum Analysis, Raman/*instrumentation/*methods; *Temperature
Abstract The operating characteristics of a pulsed (10 ns) tunable near-infrared (NIR) laser source are described for temperature-jump (T-jump) applications. A Q-switched Nd:YLF laser (approximately 10 ns pulses) with a 1 kHz repetition rate is used to pump a potassium titanyl arsenate (KTA) crystal-based optical parametric oscillator (OPO), producing approximately 1 mJ NIR pulses that are tunable (1.80-2.05 microm) across the 1.9 microm vibrational overtone band of water. This T-jump source has been coupled to a deep ultraviolet (UV) probe laser for Raman studies of protein dynamics. T-jumps of up to 30 degrees C, as measured via the O-H stretching Raman band of water, are readily achieved. Application to cytochrome c unfolding is demonstrated.
Address Department of Chemistry, Princeton University, Princeton, New Jersey 08544, 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 0003-7028 ISBN Medium
Area Expedition Conference
Notes PMID:16613628 Approved no
Call Number Equine Behaviour @ team @ Serial 3764
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Author Rodier, F.
Title [Spectral properties of porcine plasminogen: study of the acidic transition (author's transl)] Type Journal Article
Year 1976 Publication European journal of biochemistry / FEBS Abbreviated Journal Eur J Biochem
Volume (up) 63 Issue 2 Pages 553-562
Keywords Animals; Binding Sites; Guanidines; Hydrogen-Ion Concentration; *Plasminogen; Protein Binding; Protein Conformation; Spectrometry, Fluorescence; Spectrophotometry; Spectrophotometry, Ultraviolet; Swine; Temperature
Abstract The acidic transition of porcine plasminogen, prepared by affinity chromatography, was studied by non-destructive methods. These methods are based on the analysis of the behaviour of the tryptophyls under various conditions. The perturbation of the absorption and emission spectra by pH or temperature and the dynamic quenching of the intrinsic fluorescence are used to obtain information on structural changes which affect the environment of these residues. It is shown that by decreasing pH the fluorescence emission spectra are shifted toward the long wavelengths, with a broadening of the fluorescence band. The same effect can be obtained at constant pH by heating the protein solution. In order to analyze these phenomena, it is assumed that the fluorescence intensities at 355 nm and 328 nm reflect the proportion of the tryptophans which are exposed to the solvent, and buried, respectively. The plot of the ratio of the fluorescence intensities at these wavelengths versus pH or temperature leads to a titration curve showing an unmasking of tryptophans. The proportion of exposed tryptophans is measured by the dynamic fluorescence quenching technique and the data analyzed according to Lehrer. The plot of the fraction of exposed tryptophyls versus pH also shows the unmasking of these chromophores. Thermal perturbation of a solution of plaminogen at neutral pH induces a difference absorption spectrum whose amplitudes at the maxima are proportional to the number of exposed aromatic residues. The comparison with a solution of fully denatured plasminogen in 6 M guanidium chloride, where all the tryptophyls are exposed, shows that the percentage of exposure is equal to 59%. This number is significantly higher than the percentage found by the fluorescence quenching technique (20%), indicating that some tryptophyls are located in crevices, exposed to the solvent but not to the iodide. At acidic pH the absorption difference spectra induced by thermal perturbation are not classical, since they show an inversion and a new band between 300 nm and 305 nm. This band is mentioned in the literature as a minor band of tryptophan which appears when this chromophore is located in an asymmetric environment. On plotting the maximum amplitude of these spectra obtained at acidic pH versus temperature, we obtain a curve indicating that two types of antagonistic interactions are involved in the perturbation of the chromophores spectra. The spectrophotometric titration of plasminogen gives classical absorption difference spectra. By plotting the maximum amplitude at 292 nm versus pH, we obtain a titration curve with an apparent pK of 2.9 units. This pK is acidic which respect to the pK value of a normal carboxyl. This low value can be due to a positively charged group in the neighbourhood of a carboxyl, which interacts with one or more chromophores. When the carboxyl becomes protonated, this positively charged group is free and available to perturb the environment of some chromophores...
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language French Summary Language Original Title Proprietes spectrales du plasminogene porcin. Etude de la transition acide
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0014-2956 ISBN Medium
Area Expedition Conference
Notes PMID:4326 Approved no
Call Number Admin @ knut @ Serial 22
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Author Permyakov, S.E.; Khokhlova, T.I.; Nazipova, A.A.; Zhadan, A.P.; Morozova-Roche, L.A.; Permyakov, E.A.
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 (up) 65 Issue 4 Pages 984-998
Keywords 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
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 1097-0134 ISBN Medium
Area Expedition Conference
Notes PMID:17022083 Approved no
Call Number Serial 1858
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Author Bayley, P.; Martin, S.; Anson, M.
Title Temperature-jump circular dichroism: observation of chiroptical relaxation processes at millisecond time resolution Type Journal Article
Year 1975 Publication Biochemical and Biophysical Research Communications Abbreviated Journal Biochem Biophys Res Commun
Volume (up) 66 Issue 1 Pages 303-308
Keywords *Alcohol Oxidoreductases/metabolism; Animals; Circular Dichroism; Horses; Kinetics; Liver/enzymology; Mathematics; Protein Conformation; Temperature; Time Factors
Abstract
Address
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 0006-291X ISBN Medium
Area Expedition Conference
Notes PMID:1172440 Approved no
Call Number Equine Behaviour @ team @ Serial 3816
Permanent link to this record