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Neotropical Entomology Jun 2024The use of Meliponini for crop pollination in protected environments is practically non-existent. One of the reasons is the difficulty of acclimatizing Meliponini to the...
The use of Meliponini for crop pollination in protected environments is practically non-existent. One of the reasons is the difficulty of acclimatizing Meliponini to the temperature and light conditions inside greenhouses. We investigated how covering materials used in greenhouses, which filter different intensities of ultraviolet (UV) light, affect the foraging behaviors, flight orientation, attraction to walls and ceilings, and mortality of Scaptotrigona cf. postica (Letreille), Frieseomelitta varia (Lepeletier), and Melipona quadrifasciata (Lepeletier). The experiments were conducted in 5.3 m arenas covered with four types of plastic films that do not polarize sunlight, with UV transmittance levels ranging from 0.1 to 54%, compared to a transparent glass control. The temperature inside the arenas varied between treatments, from 27 ± 3°C to 31 ± 2°C. All three species collected resources and returned to the colony, regardless of the covering material. However, the proportion of this behavior, the number of bees attracted to the ceiling and wall, and mortality varied among treatments and/or throughout the confinement days for each species. Melipona quadrifasciata and F. varia acclimatized better to the confined environments than S. cf. postica and showed consistent resource collection behavior throughout the confinement days in all tested materials, except for the one that filtered around 90% of UV. In all three species, the mortality gradually decreased throughout the confinement days. The results indicate that the choice of covering material, considering its optical characteristics, can be crucial to ensure greater effectiveness of the pollination services provided by stingless bees in protected systems.
Topics: Bees; Animals; Brazil; Ultraviolet Rays; Acclimatization; Temperature; Pollination; Feeding Behavior; Flight, Animal
PubMed: 38656591
DOI: 10.1007/s13744-024-01140-x -
Scientific Reports Nov 2020Benefits obtained after heat acclimation/acclimatization should be completely lost after an estimated period of 6 weeks. However, this estimate is still hypothetical....
Benefits obtained after heat acclimation/acclimatization should be completely lost after an estimated period of 6 weeks. However, this estimate is still hypothetical. We evaluate the long-term effects of heat acclimatization on the level of heat tolerance. Physiological and subjective markers of heat tolerance were assessed during a heat stress test (HST: 3 × 8-min runs outdoors [~ 40 °C and 20% RH] at 50% of their estimated speed at VO) performed on the 2nd day upon arrival to the desert military base in the United Arab Emirates after a first day of mostly passive exposure to heat. Among the 50 male French soldiers, 25 partook in a 4-month military mission in countries characterized by a hot environment ~ 6 months prior to the study (HA). The other 25 participants were never heat acclimatized (CT). Rectal temperature (p = 0.023), heart rate (p = 0.033), and perceived exertion (p = 0.043) were lower in the HA than CT group at the end of HST. Soldiers who experienced a former 4-month period of natural heat acclimatization very likely had a higher level of heat tolerance during exercise in the heat, even 6 months after returning from the previous desert mission, than that of their non-acclimatized counterparts.
Topics: Acclimatization; Adult; Body Temperature; Heart Rate; Hot Temperature; Humans; Male; Physical Exertion; Thermotolerance
PubMed: 33219295
DOI: 10.1038/s41598-020-77358-7 -
Graefe's Archive For Clinical and... Mar 2006To evaluate the relationship between hypobaric hypoxia acclimatization and intraocular pressure (IOP) during ascent, acclimatization, and descent between 2286 m and 5050...
BACKGROUND
To evaluate the relationship between hypobaric hypoxia acclimatization and intraocular pressure (IOP) during ascent, acclimatization, and descent between 2286 m and 5050 m.
METHODS
The following acclimatization-indicative physiological parameters were compared daily with IOP changes in eight healthy climbers of the 2003 Greek Karakorum expedition in altitude stages between 500 m and 5050 m: hemoglobin oxygen saturation (PO2), resting heart rate, blood pressure, retinal findings, and the Lake Louise score for acclimatization grading.
RESULTS
IOP decreased significantly in the ascent phase (0.58 mmHg/100 m) and recovered (0.71 mmHg/100 m) during acclimatization and descent. A direct proportional correlation between decreases in PO2 and IOP was evaluated. Arterial blood pulse and pressure increased during acclimatization, while IOP decreased. No retinal hemorrhages were observed in well-acclimatized and incompletely acclimatized climbers.
CONCLUSIONS
Every new active exposure to hypobaric hypoxia in the ascent phase induced a decrease in the IOP parallel to the PO2 decrease and to the level of acclimatization. The results from our study suggest that IOP changes are related to hypoxia-induced respiratory alkalosis and acclimatization stage, which could be used as a simple mobile screening test for acclimatization level to reveal acute mountain sickness and its severe consequences.
Topics: Acclimatization; Adult; Aged; Alkalosis, Respiratory; Altitude; Altitude Sickness; Atmospheric Pressure; Blood Pressure; Female; Heart Rate; Humans; Hypoxia; Intraocular Pressure; Male; Middle Aged; Partial Pressure
PubMed: 16133013
DOI: 10.1007/s00417-005-1174-1 -
Bioresource Technology Jan 2020The methane productivity and long chain fatty acids (LCFAs) degradation capability of unacclimatized seed sludge (USS) and acclimatized seed sludge (ASS) at different...
The methane productivity and long chain fatty acids (LCFAs) degradation capability of unacclimatized seed sludge (USS) and acclimatized seed sludge (ASS) at different substrate ratios of fats oil and grease (FOG) and mixed sewage sludge were investigated in this study. Biogas produced in ASS in initial phase of anaerobic digestion had higher methane content (65-76%) than that in USS (26-73%). The degradation of major LCFAs in the ASS was 22-80%, 33-191%, and 7-64% higher for the substrate ratios of 100:10, 100:20, and 100:30, respectively, as compared to the LCFAs' degradation in USS. Microbial acclimatization increased the population of Firmicutes (40%), Bacteroidetes (32%), Synergistetes (10%), and Euryarchaeota (8%) in ASS, which supported the faster rate of LCFAs degradation for its later conversion to methane. The significant abundance of Syntrophomonas and Methanosarcina genera in ASS supported faster generation rate of methane in an obligatory syntrophic relationship.
Topics: Acclimatization; Anaerobiosis; Biofuels; Bioreactors; Digestion; Methane; Microbiota; Sewage
PubMed: 31677410
DOI: 10.1016/j.biortech.2019.122294 -
Bio Systems Jul 2014In order to describe the dynamic behavior of a complex biological system, it is useful to combine models integrating processes at different levels and with temporal...
In order to describe the dynamic behavior of a complex biological system, it is useful to combine models integrating processes at different levels and with temporal dependencies. Such combinations are necessary for modeling acclimatization, a phenomenon where changes in environmental conditions can induce drastic changes in the behavior of a biological system. In this article we formalize the use of hybrid systems as a tool to model this kind of biological behavior. A modeling scheme called strong switches is proposed. It allows one to take into account both minor adjustments to the coefficients of a continuous model, and, more interestingly, large-scale changes to the structure of the model. We illustrate the proposed methodology with two applications: acclimatization in wine fermentation kinetics, and acclimatization of osteo-adipo differentiation system linking stimulus signals to bone mass.
Topics: Acclimatization; Animals; Bone and Bones; Cell Differentiation; Environment; Fermentation; Humans; Hybridization, Genetic; Kinetics; Models, Biological; Wine
PubMed: 24892552
DOI: 10.1016/j.biosystems.2014.05.007 -
Experimental Physiology Jan 2016At high altitude the barometric pressure falls, challenging oxygen delivery to the tissues. Thus, whilst hypoxia is not the only physiological stress encountered at high... (Review)
Review
At high altitude the barometric pressure falls, challenging oxygen delivery to the tissues. Thus, whilst hypoxia is not the only physiological stress encountered at high altitude, low arterial P(O2) is a sustained feature, even after allowing adequate time for acclimatization. Cardiac and skeletal muscle energy metabolism is altered in subjects at, or returning from, high altitude. In the heart, energetic reserve falls, as indicated by lower phosphocreatine-to-ATP ratios. The underlying mechanism is unknown, but in the hypoxic rat heart fatty acid oxidation and respiratory capacity are decreased, whilst pyruvate oxidation is also lower after sustained hypoxic exposure. In skeletal muscle, there is not a consensus. With prolonged exposure to extreme high altitude (>5500 m) a loss of muscle mitochondrial density is seen, but this was not observed in a simulated ascent of Everest in hypobaric chambers. At more moderate high altitude, decreased respiratory capacity may occur without changes in mitochondrial volume density, and fat oxidation may be downregulated, although this is not seen in all studies. The underlying mechanisms, including the possible role of hypoxia-signalling pathways, remain to be resolved, particularly in light of confounding factors in the high-altitude environment. In high-altitude-adapted Tibetan natives, however, there is evidence of natural selection centred around the hypoxia-inducible factor pathway, and metabolic features in this population (e.g. low cardiac phosphocreatine-to-ATP ratios, increased cardiac glucose uptake and lower muscle mitochondrial densities) share similarities with those in acclimatized lowlanders, supporting a possible role for the hypoxia-inducible factor pathway in the metabolic response of cardiac and skeletal muscle energy metabolism to high altitude.
Topics: Acclimatization; Air Pressure; Altitude; Animals; Energy Metabolism; Heart; Humans; Muscle, Skeletal; Myocardium
PubMed: 26315373
DOI: 10.1113/EP085317 -
Comparative Biochemistry and... 2021One of the principal goals of comparative biology is the elucidation of mechanisms by which organisms adapt to different environments. The study of enzyme structure,... (Review)
Review
One of the principal goals of comparative biology is the elucidation of mechanisms by which organisms adapt to different environments. The study of enzyme structure, function, and stability has contributed significantly to this effort, by revealing adaptation at a molecular level. Comparative biochemistry, including enzymology, necessarily pursues a reductionist approach in describing the function and structure of biomolecules, allowing more straightforward study of molecular systems by removing much of the complexity of their biological milieu. Although this reductionism has allowed a remarkable series of discoveries linking chemical processes to metabolism and to whole-organism function in the context of the environment, it also has the potential to mislead when careful consideration is not made of the simplifying assumptions inherent to such research. In this review, a brief history of the growth of enzymology, its reliance on a reductionist philosophy, and its contributions to our understanding of biological systems is given. Examples then are provided of research techniques, based on a reductionist approach, that have advanced our knowledge about enzyme adaptation to environmental stresses, including stability assays, enzyme kinetics, and the impact of solute composition on enzyme function. In each case, the benefits of the reductionist nature of the approach is emphasized, notable advances are described, but potential drawbacks due to inherent oversimplification of the study system are also identified.
Topics: Acclimatization; Animals; Enzymes; Humans
PubMed: 33600949
DOI: 10.1016/j.cbpb.2021.110574 -
Journal of Science and Medicine in Sport Feb 2018
Topics: Acclimatization; Athletic Injuries; Exercise; Female; Humans; Steam Bath; Thermotolerance
PubMed: 29275863
DOI: 10.1016/j.jsams.2017.12.003 -
Concours Medical Apr 1955
Topics: Acclimatization; Altitude; Humans
PubMed: 14379649
DOI: No ID Found -
Zoo Biology 2015Seasonal acclimatization in terrestrial mammals in the Northern Hemisphere involves changes in coat insulation. It is more economical to provide increased insulation...
Seasonal acclimatization in terrestrial mammals in the Northern Hemisphere involves changes in coat insulation. It is more economical to provide increased insulation than increased heat production for protection against the cold. This study was done to test a technique for the non-invasive measurement of mammal coat insulation and to measure coat insulation over several seasons on captive exotics. The working hypothesis was that species that have no coat or have a coat that does not change seasonally do not acclimatize seasonally. Three surface temperature readings were measured from the torso area. The insulation was calculated using measured metabolic rates and body temperature when possible. The African elephants, giraffe and okapi did not acclimatize with average maximum insulation values of 0.256°Cm(2) W(-1) . The Amur tigers and mountain goats acclimatized to seasonal ambient conditions by increasing the insulation values of the hair coats in the cold with an average maximum insulation values of 0.811°Cm(2) W(-1) . The cold adapted species are more than three times more insulated in the cold than the equatorial species. The husbandry implications of exotics that have no ability to acclimatize to Northern Hemisphere seasonal ambient changes are profound. Giraffe, African elephants, and okapi when exposed to cold conditions with ambient air temperatures below 21°C will use body energy reserves to maintain a heat balance and will require housing that provides ambient conditions of 21°C.
Topics: Acclimatization; Animals; Animals, Zoo; Body Temperature Regulation; Cold Temperature; Hair; Seasons
PubMed: 26087320
DOI: 10.1002/zoo.21219