scholarly journals The interplay of temperature and protons in the modulation of oxygen binding by squid blood

1992 ◽  
Vol 281 (3) ◽  
pp. 725-728 ◽  
Author(s):  
B Giardina ◽  
S G Condò ◽  
O Brix
Keyword(s):  
Rangifer Tarandus ◽  
Effect Of Temperature ◽  
Strong Temperature Dependence ◽  
Oxygen Binding ◽  
Experimental Conditions ◽  
Ovibos Moschatus ◽  
High Affinity ◽  
Loading And Unloading ◽  
Musk Ox ◽  
Oxygen Equilibrium Curve

An extensive set of data relating to the binding of oxygen by haemocyanin from the squid Todarodes sagittatus has been collected under various experimental conditions. The results obtained show that, within the range of physiological pH, the concentration of protons affects mainly the high-affinity state of the molecule without significantly affecting the low-affinity state. As far as the effect of temperature is concerned, the data show a characteristic feature which is very similar to that previously described in the case of haemoglobins from Arctic mammals such as reindeer (Rangifer tarandus) and musk ox. (Ovibos moschatus). The shape of the oxygen equilibrium curve shows strong temperature-dependence, since the overall heat of the binding of oxygen to the low-affinity state of the molecule is strongly exothermic and that to the high-affinity state is very close to zero. The results provide an outline of the intramolecular compromise that, through the interplay of temperature and protons, optimizes the loading and unloading of oxygen under the various environmental conditions experienced by this species of squid.

Oxygen binding of erythrocruorin and coelomic cell haemoglobin from the terebellid polychaete Neoamphitrite figulus related to some environmental factors

1982 ◽  
Vol 62 (2) ◽  
pp. 373-384 ◽  
Author(s):  
Rufus M. G. Wells ◽  
Lynda M. Warren
Keyword(s):  
Haemoglobin Concentration ◽  
Log P ◽  
Oxygen Binding ◽  
Transfer System ◽  
Equilibrium Curve ◽  
High Affinity ◽  
Coelomic Cells ◽  
Hyperbolic Equilibrium ◽  
Oxygen Equilibrium Curve

Measurements of pH, oxygen content, O2-combining capacity, and haemoglobin concentration were made for the vascular blood of the burrowing polychaete Neoamphitrite figulus in order to assess the role of its two respiratory pigments in respiration. The oxygen equilibrium curve of the erythrocruorin (extracellular haemoglobin) in the vessels was sigmoidal, having an n50 value of 1·5 and a low affinity for oxygen as determined by the P50 which was 26 mmHg at pH 7·31 and 18 °C. O2-binding by the erythrocruorin is sensitive to changes in pH (Δ log P50/Δ log pH = –0·24 to –0·29). The coelomic cell haemoglobin has a hyperbolic equilibrium curve (n50 = 1·0) and a high affinity for oxygen (P50 = 4·5 mmHg) independent of pH, suggesting an oxygen transfer system from the erythrocruorin to the coelomic cells.

scholarly journals Effect of temperature on the formation of Highly-oxygenated Organic Molecules (HOM) from alpha-pinene ozonolysis

2018 ◽  
Author(s):  
Lauriane L. J. Quéléver ◽  
Kasper Kristensen ◽  
Louise Jensen ◽  
Bernadette Rosati ◽  
Ricky Teiwes ◽  
...  
Keyword(s):  
Organic Molecules ◽  
Peroxy Radical ◽  
Effect Of Temperature ◽  
Strong Temperature Dependence ◽  
Peroxy Radicals ◽  
Atmospheric Conditions ◽  
Experimental Conditions ◽  
Mass Spectral ◽  
Alpha Pinene ◽  
Lower Temperature

Abstract. Highly-oxygenated Organic Molecules (HOM) are important contributors to Secondary Organic Aerosol (SOA) and New-Particle Formation (NPF) in the boreal atmosphere. This newly discovered class of molecules is efficiently formed from atmospheric oxidation of biogenic volatile organic compounds (VOC), such as monoterpenes, through a process called autoxidation. This process, in which peroxy-radical intermediates isomerize to allow addition of molecular oxygen, is expected to be highly temperature-dependent. Here, we studied the dynamics of HOM formation during alpha-pinene ozonolysis experiments performed at three different temperatures, 20 °C, 0 °C and −15 °C, in the Aarhus University Research on Aerosol (AURA) chamber. We found that the HOM formation, under our experimental conditions (50 ppb alpha-pinene, 100 ppb ozone), decreased considerably as temperature decreased, with molar yields dropping by around a factor of 50 when experiments were performed at 0 °C, compared to 20 °C. At −15 °C, the HOM signals were already close to the detection limit of the nitrate-based Chemical Ionization Atmospheric Pressure interface Time Of Flight (CI-APi-TOF) mass spectrometer used for measuring gas-phase HOM. Surprisingly, very little difference was seen in the mass spectral distribution of the HOM molecules of interest at 0 °C and 20 °C, with e.g. the ratios between the typical HOM products C10H14O7, C10H14O9, and C10H14O11 remaining fairly constant. The more oxidized species have undergone more isomerization steps, yet, at lower temperature, they did not decrease more than the less oxidized species. One possible explanation is be that the rate-limiting step forming these HOM occurs before the products become oxygenated enough to be detected by our CI-APi-TOF (i.e. typically seven or more oxygen atoms). The strong temperature dependence of HOM formation was observed under temperatures highly relevant for the boreal forest, but the exact magnitude of this effect in the atmosphere will be much more complex: the fate of peroxy-radicals is a competition between autoxidation (influenced by temperature and VOC type) and bimolecular termination pathways (influenced mainly by concentration of reaction partners). While the temperature influence is likely smaller in the boreal atmosphere than in our chamber, the magnitude and complexity of this effect clearly deserves more consideration in future studies in order to estimate the ultimate role of HOM on SOA and NPF under different atmospheric conditions.

Zoological Perspectives on the Late Glacial

2007 ◽  
Author(s):  
D. W. Yalden
Keyword(s):  
Rangifer Tarandus ◽  
Late Glacial ◽  
The Arctic ◽  
Background Information ◽  
Ovibos Moschatus ◽  
Mammal Fauna ◽  
Dicrostonyx Torquatus ◽  
The Church ◽  
Musk Ox ◽  
Woolly Mammoth

Enough mammal specimens of Late Glacial date from the British Isles have been subjected to radiocarbon dating to provide a reliable outline of the likely large mammal fauna of the time, though the accompanying fauna of small mammals has mostly been assigned to this period on associative, rather than direct, dating. These give an adequate zoological background against which to examine the suggested identities of the large mammals depicted at Church Hole, Creswell Crags. This background information is reviewed in this chapter. While Bison priscus was certainly present earlier in the Devensian, there is no evidence that Bison returned to Britain in the Late Glacial, but aurochs (Bos primigenius) did so, and must be considered a more probable identification. The evidence that ibex (Capra ibex) ever occurred in Britain is very dubious, which cast serious doubt on the original identification of the Church Hole Panel III engraving as being of this species. In this case, discussion and reinterpretation of the engravings during the course of the conference suggested a better resolution than the zoological one suggested at the time. The ice of the Devensian glacial maximum, at about 20–18 ka BP, is believed to have covered all of northern Great Britain and Ireland, leaving smaller areas of the south of each island free of ice but occupied by tundra, permafrost, conditions. It is most unlikely that any of the present mammal fauna could have survived here then, though the possibilities that mountain hare (Lepus timidus) and stoat (Mustela erminea) did so must be conceded—both range well into the Arctic at the present day. The severity of the climate, and the likely nature of the mammal fauna, is indicated by the presence of musk ox (Ovibos moschatus) (Fisherton, Wiltshire, but undated) and the possible polar bear (Ursus maritimus) (Creag nan Uamh, Sutherland, 18.9 ka: Kitchener and Bonsall 1997) that date to this time. Barnwell Station, Cambridge, has a<sup>14</sup> C date on peat of 19.5 ka BP, and a fauna including woolly mammoth (Mammuthus primigenius), woolly rhinoceros (Coelodonta antiquitatis), reindeer (Rangifer tarandus), and horse (Equus ferus). Dated specimens fromsouthern Ireland are also relevant: collared lemming (Dicrostonyx torquatus) at20.3 ka BP, woolly mammoth at 20.36 ka BP and Arctic fox (Alopex lagopus) at 19.95 ka BP, all from Castlepook Cave, Cork (Woodman et al. 1997).

scholarly journals Effect of temperature on the formation of highly oxygenated organic molecules (HOMs) from alpha-pinene ozonolysis

2019 ◽  
Vol 19 (11) ◽  
pp. 7609-7625 ◽  
Author(s):  
Lauriane L. J. Quéléver ◽  
Kasper Kristensen ◽  
Louise Normann Jensen ◽  
Bernadette Rosati ◽  
Ricky Teiwes ◽  
...  
Keyword(s):  
Organic Molecules ◽  
Peroxy Radical ◽  
Effect Of Temperature ◽  
Strong Temperature Dependence ◽  
Peroxy Radicals ◽  
Atmospheric Conditions ◽  
Experimental Conditions ◽  
Alpha Pinene ◽  
Different Temperatures ◽  
Lower Temperature

Abstract. Highly oxygenated organic molecules (HOMs) are important contributors to secondary organic aerosol (SOA) and new-particle formation (NPF) in the boreal atmosphere. This newly discovered class of molecules is efficiently formed from atmospheric oxidation of biogenic volatile organic compounds (VOCs), such as monoterpenes, through a process called autoxidation. This process, in which peroxy-radical intermediates isomerize to allow addition of molecular oxygen, is expected to be highly temperature-dependent. Here, we studied the dynamics of HOM formation during α-pinene ozonolysis experiments performed at three different temperatures, 20, 0 and −15 ∘C, in the Aarhus University Research on Aerosol (AURA) chamber. We found that the HOM formation, under our experimental conditions (50 ppb α-pinene and 100 ppb ozone), decreased considerably at lower temperature, with molar yields dropping by around a factor of 50 when experiments were performed at 0 ∘C, compared to 20 ∘C. At −15 ∘C, the HOM signals were already close to the detection limit of the nitrate-based chemical ionization atmospheric pressure interface time-of-flight (CI-APi-TOF) mass spectrometer used for measuring gas-phase HOMs. Surprisingly, comparing spectra measured at 0 and 20 ∘C, ratios between HOMs of different oxidation levels, e.g., the typical HOM products C10H14O7, C10H14O9, and C10H14O11, changed considerably less than the total HOM yields. More oxidized species have undergone more isomerization steps; yet, at lower temperature, they did not decrease more than the less oxidized species. One possible explanation is that the primary rate-limiting steps forming these HOMs occur before the products become oxygenated enough to be detected by our CI-APi-TOF (i.e., typically seven or more oxygen atoms). The strong temperature dependence of HOM formation was observed under temperatures highly relevant to the boreal forest, but the exact magnitude of this effect in the atmosphere will be much more complex: the fate of peroxy radicals is a competition between autoxidation (influenced by temperature and VOC type) and bimolecular termination pathways (influenced mainly by concentration of reaction partners). While the temperature influence is likely smaller in the boreal atmosphere than in our chamber, both the magnitude and complexity of this effect clearly deserve more consideration in future studies in order to estimate the ultimate role of HOMs on SOA and NPF under different atmospheric conditions.

РАДИОУГЛЕРОДНЫЕ ДАТИРОВКИ ПАЛЕОНТОЛОГИЧЕСКИХ ОБРАЗЦОВ ВЕРХНЕГО ПЛЕЙСТОЦЕНА НИЖНЕЙ ОБИ

2020 ◽  
Author(s):  
I. Zolnikov ◽  
◽  
A. Vybornov ◽  
A. Anoikin ◽  
A. Postnov ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Rangifer Tarandus ◽  
Western Siberia ◽  
Budker Institute ◽  
Mammuthus Primigenius ◽  
Upper Pleistocene ◽  
Ovibos Moschatus ◽  
The North

In the course of studies conducted by IAET SB RAS in the Lower Ob in 2016–2019, the understanding of the conditions for settlement of the Paleolithic population in the north of Western Siberia was significantly supplemented. Dating of a series of paleontological finds was carried out at the "Accelerated mass spectrometer of the Budker Institute of Nucle- ar Physics of SB RAS". The dates obtained show the distribution of the main representatives of the Upper Pleistocene fauna of Subarctica: Mammuthus primigenius – 50,000–15,000 BP, Coelodonta antiquitatis – 43,000–38,000 BP and 27,000–25,000 BP, Rangifer tarandus, Equus ferus – 40,000–10,000 BP, Bison sp. – 50,000–40,000 BP, Ovibos moschatus – 41,000–32,000 BP.

Applicability of Instability Index for In vitro Protein Stability Prediction

2019 ◽  
Vol 26 (5) ◽  
pp. 339-347 ◽  
Author(s):  
Dilani G. Gamage ◽  
Ajith Gunaratne ◽  
Gopal R. Periyannan ◽  
Timothy G. Russell
Keyword(s):  
Protein Stability ◽  
Caulobacter Crescentus ◽  
Effect Of Temperature ◽  
Instability Index ◽  
Dipeptide Composition ◽  
Experimental Conditions ◽  
The Stability ◽  
Vitro Protein

Background: The dipeptide composition-based Instability Index (II) is one of the protein primary structure-dependent methods available for in vivo protein stability predictions. As per this method, proteins with II value below 40 are stable proteins. Intracellular protein stability principles guided the original development of the II method. However, the use of the II method for in vitro protein stability predictions raises questions about the validity of applying the II method under experimental conditions that are different from the in vivo setting. Objective: The aim of this study is to experimentally test the validity of the use of II as an in vitro protein stability predictor. Methods: A representative protein CCM (CCM - Caulobacter crescentus metalloprotein) that rapidly degrades under in vitro conditions was used to probe the dipeptide sequence-dependent degradation properties of CCM by generating CCM mutants to represent stable and unstable II values. A comparative degradation analysis was carried out under in vitro conditions using wildtype CCM, CCM mutants and two other candidate proteins: metallo-β-lactamase L1 and α -S1- casein representing stable, borderline stable/unstable, and unstable proteins as per the II predictions. The effect of temperature and a protein stabilizing agent on CCM degradation was also tested. Results: Data support the dipeptide composition-dependent protein stability/instability in wt-CCM and mutants as predicted by the II method under in vitro conditions. However, the II failed to accurately represent the stability of other tested proteins. Data indicate the influence of protein environmental factors on the autoproteolysis of proteins. Conclusion: Broader application of the II method for the prediction of protein stability under in vitro conditions is questionable as the stability of the protein may be dependent not only on the intrinsic nature of the protein but also on the conditions of the protein milieu.

Is there a cost of parasites to caribou?

Parasitology ◽  
2008 ◽  
Vol 136 (2) ◽  
pp. 253-265 ◽  
Author(s):  
J. HUGHES ◽  
S. D. ALBON ◽  
R. J. IRVINE ◽  
S. WOODIN
Keyword(s):  
Rangifer Tarandus ◽  
Parasite Species ◽  
Negative Relationship ◽  
Apparent Competition ◽  
Range Shift ◽  
The Arctic ◽  
Contributory Factor ◽  
Ovibos Moschatus ◽  
Winter Range ◽  
Nematode Parasites

SUMMARYMacroparasites potentially play a significant but often ignored role in the ecology and dynamics of wild ruminant populations. In the Arctic, parasites may impact on host populations by exacerbating the effects of seasonal and limited forage availability on the condition, fecundity and survival of individuals. We studied the effects of abomasal nematode parasites and warble flies, Hypoderma tarandi, on condition and pregnancy of caribou Rangifer tarandus in the Dolphin-Union herd, Nunavut, Canada. By the end of winter, female caribou over 2 years old showed a significant decrease in body weight with increasing nematode burden, and a decrease in back fat depth with increasing warble abundance. These effects were exaggerated in the non-pregnant fraction of the population. High warble larvae burdens were also associated with significantly reduced probability of being pregnant. Our research demonstrates a negative relationship between parasites and caribou condition that may have consequences for their fitness. Additionally, we discuss the possibility that muskox Ovibos moschatus share some parasite species with the caribou and could lead to elevated burdens in the sympatric host. Parasites may have been a contributory factor in a previous winter range-shift of the caribou herd and this may reflect a form of apparent competition between the two ungulate species.

Ovibos moschatus (Musk ox)

1968 ◽  
pp. 177-179
Author(s):  
T. C. Hsu ◽  
Kurt Benirschke
Keyword(s):  
Ovibos Moschatus ◽  
Musk Ox

scholarly journals Effect of temperature on acid hydrolysis of Jerusalem artichoke as raw material for ethanol production

2013 ◽  
pp. 279-287 ◽  
Author(s):  
Radojka Razmovski ◽  
Vesna Vucurovic ◽  
Uros Miljic ◽  
Vladimir Puskas
Keyword(s):  
Hold Time ◽  
Jerusalem Artichoke ◽  
Raw Material ◽  
Effect Of Temperature ◽  
Industrial Biotechnology ◽  
Microbial Conversion ◽  
Experimental Conditions ◽  
Theoretical Yield ◽  
Renewable Raw Material ◽  
Layer Chromatography

Jerusalem artichoke (JA) is a low-requirement crop, which does not interfere with food chain, and is a promising carbon source for industrial fermentation. Microbial conversion of such a renewable raw material to useful products, such as ethanol, is an important objective in industrial biotechnology. In this study, ethanol was efficiently produced from the hydrolyzates of JA obtained at different pH values (pH 2.5, pH 3.0 and pH 3.5), temperature (120, 130, 132 and 134?C) and hold time (30 and 60 min) by Saccharomyces cerevisiae. The efficient degradation of JA by HCl under certain experimental conditions was confirmed by thin-layer chromatography. Ethanol concentration of 7.52% (w/w), which corresponds to 93.89 % of the theoretical yield is achieved by ethanol fermentation of JA hydrolyzate obtained at pH 2.5.

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