Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ACCLIMATIZATION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,027 records · Page 57Linked to original sources
PubMed2006

Microbial decolorization of reactive black-5 in a two-stage anaerobic-aerobic reactor using acclimatized activated textile sludge.

A two-stage anaerobic-aerobic treatment process based on mixed culture of bacteria isolated from textile dye effluent was used to degrade reactive black 5 dye (RB-5). The anaerobic step was studied in more detail by varying the dye concentration from 100 to 3000 mg l(-1). The results showed that major decolorization was achieved during the anaerobic process. The time required for decolorization by > 90% increased as the concentration of the dye increased. It was also found that maintaining dissolved oxygen (DO) concentration below 0.5 mg l(-1 )and addition of a co-substrate viz., glucose, facilitates anaerobic decolorization reaction remarkably. An attempt was made to identify the metabolites formed in anaerobic process by using high performance liquid chromatography (HPLC) and UV-VIS spectrophotometry. A plate assay was performed for the detection of dominant decolorizing bacteria. Only a few bacterial colonies with high clearing zones (decolorization zones) were found. The results showed that under anaerobic condition RB-5 molecules were reduced and aromatic amines were generated. The aromatic amine metabolite was partly removed in subsequent aerobic bio-treatment. It was possible to achieve more than 90% decolorization and approximately 46% reduction in amine metabolite concentration through two-stage anaerobic-aerobic treatment after a reaction period of 2 days.

Aerobiosis↗
PubMed1993

Circannual variation in the fatty acid composition of high-density lipoprotein phospholipids during acclimatization in trout.

A circannual variation in the fatty acid composition of plasma and high-density lipoprotein (HDL) phospholipids occurs in rainbow trout (Oncorhynchus mykiss) in response to seasonal alterations in environmental water temperature. The compensatory mechanisms employed in cold adaptation include a decrease in the level of saturated fatty acids and of monoenes of the oleic acid (n-9) family and an increase in the level of unsaturated fatty acids of the linolenic acid (n-3) family, especially in docosahexaenoic acid (22:6(n-3)). The present study demonstrates that in trout, a poikilothermic vertebrate, the weight percentage of 22:6(n-3) in HDL phospholipids is inversely correlated (r = -0.88, P < 0.0001) with water temperature.

Animals↗
PubMed1985

Responses of blood volume and red cell mass in two strains of rats acclimatized to high altitude.

Two strains of rats, one that adapts successfully to high altitude (HA) (Madison = M) and the other that adapts poorly and suffers a high mortality rate at high altitude (Hilltop = H) were studied during 40 days of exposure to a simulated altitude of 18 000 ft (5450 m; PB = 175). The time rate of change of blood volume (TBV), red cell volume (RBCV), plasma volume (PV) and hematocrit (Hct), and the interrelationships of these variables, particularly emphasizing TBV, PV and Hct as functions of RBCV, were compared in the M and H strains. Sea level control values in the two strains were not different, but by the 5th day at HA RBCV and TBV had expanded to a greater extent in H than M - a difference that was maintained throughout the 40 days - but PV decreased similarly in the two strains. By 30 days the inter-strain differences of RBCV, TBV, and Hct became more pronounced but still no difference of PV was noted. The most significant feature was the greater polycythemic response of H, which at the extreme range was not associated with any further decrease of PV and therefore resulted in rapid expansion of TBV. The probable effects of these responses on cardiovascular function and oxygen transport are discussed, comparing the differences of H and M strains, which became maladaptive in H. The similarity of the responses in H to those of man with chronic mountain sickness is noted.

Adaptation, Physiological↗
PubMed1985

Effects of acute heat exposure on respiratory metabolism and blood glucose in freshwater fishes, Prochilodus scrofa (curimbatá) and Cyprinus carpio (carp) acclimatized to tropical winter.

Routine oxygen consumption and blood glucose were determined from freshwater fishes, Prochilodus scrofa and Cyprinus carpio, exposed at high temperatures for 1 hr. Prochilodus scrofa had a significantly higher rate of oxygen consumption at 30 degrees C than at 25 degrees C, and carp higher at 25 degrees C than at 30 degrees C. Blood glucose was significantly higher for Cyprinus carpio than for Prochilodus scrofa at 25 and 30 degrees C; however, after exposure to these temperatures for 1 hr blood glucose did not change significantly for both species. The results suggest that these interspecific variations may be linked to the differences between native and foreign fishes and their way of life.

Animals↗
PubMed2006

Acclimatable cardiac and ventilatory responses to copper in the freshwater crayfish Procambarus clarkii.

Mortality and physiological tests following exposure to waterborne copper were performed in the red swamp crayfish Procambarus clarkii from a central Italian population. Mortality tests gave an estimated 96 h LC50 value (with 95% confidence limits) of 162 (132-211) mg L(-1) waterborne copper II. Variations in cardiac and ventilatory rates were simultaneously monitored using a non-invasive plethysmographic technique. In experiments with different sub-lethal copper concentrations (control, 0.5, 1 and 10 mg L(-1)) performed at different times (3, 6, 96 h), copper exposure elicited a reduction in both heart and scaphognatite rates. Following exposure to 10 mg L(-1) copper for 96 h, the heart and scaphognatite rates decreased to about 35% of the initial values. The reduction was fully reversible, since crayfish exposed to 0.5, 1 and 10 mg Cu L(-1) for 96 h resumed control rates after a 3-h residence in clean water. In crayfish pre-exposed (96 h) to sub-lethal copper concentrations (0.1 and 1 mg L(-1)) and then held in control water (3 h), the reduction of heart and scaphognatite rates after exposure to 10 mg Cu L(-1) were significantly lower than in specimens pre-exposed to control water. Therefore, copper induces a concentration and time dependent reduction of both cardiac and ventilatory activity in P. clarkii; these responses can be reduced or fully abolished by pre-exposure to sub-lethal levels of the metal.

Animals↗
PubMed2005

Heat acclimatization and sunshine cause false indications of mortality due to ozone.

We used graphic analysis and generalized additive modeling to assess whether mortality that is often attributed to ozone and sometimes to < 10-microm particulate matter (PM10) and sulfur dioxide in hot weather results from confounding by neglected weather factors. When mean daily air temperatures exceeded 18 degrees C, mortality at age > or = 65 years, in Greater London 1991-2002 rose and at each temperature was generally higher in early summer than later after exposure to hot weather. Ozone, and to lesser degrees PM10 and sulfur dioxide, followed similar patterns. At each temperature, high levels of ozone and PM10 tended to be associated with sunshine, and high PM10 and sulfur dioxide with low wind, both of which will increase heat stress. With allowance for these confounding factors, generalized additive modeling showed no significant mortality due to ozone, to PM10, or to sulfur dioxide. We conclude that the pollutants played little part in excess mortality associated with hot weather.

Adaptation, Physiological↗
PubMed1976

[Multiplicity of the molecular forms of acetylcholinesterase and thermal acclimatization in Carassius auratus].

Multiple forms of acetylcholinesterase have been studied in Goldfish adapted to 15 degrees C and 25 degrees C. Three forms of enzyme (sedimenting at 18S, 12S and 5S) could be distinguished by sucrose gradient centrifugation. Their molecular and enzymatic properties did not vary with environmental temperature. It was noted that the relative proportion of the three forms differed between brain and muscle extracts, the 18S forms predominating in muscle (about 75 per cent) the 12S forms being more abundant in the brain, suggesting a physiological differentiation between these forms. The latter form varied from 48 per cent to 70 per cent in Goldfish adapted to 15 degrees and 25 degrees C respectively. The relative efficiency of saline buffer solubilization for each form also depended on the tissue used and in all cases decreased with rising environmental temperature. These two facts are taken to reflect interactions between acetylcholinesterase and membrane that depend on the nature of the membrane and probably involve the aliphatic chains of its phospholipids. The greater case of solubilization found in the low temperature adapted fish may be a function of the increased fluidity of the cellular membranes formed at lower temperatures.

Animals↗
PubMed1985

Effects of Quantum Flux Density on Photosynthesis and Chloroplast Ultrastructure in Tissue-Cultured Plantlets and Seedlings of Liquidambar styraciflua L. towards Improved Acclimatization and Field Survival.

Liquidambar styraciflua L. seedlings and tissue-cultured plantlets were grown under high, medium, or low (315, 155, or 50 microeinsteins per square meter per second photosynthetically active radiation) quantum flux densities. Net photosynthesis, chlorophyll content, and chloroplast ultrastructure of leaves differentiated from these conditions were investigated. Seedling photosynthetic rates at light saturation were positively related to light pretreatments, being 6.44, 4.73, and 2.75 milligrams CO(2) per square decimeter per hour for high, medium, and low light, respectively. Cultured plantlets under all light conditions had appreciably higher photosynthetic rates than noncultured seedlings; corresponding rates were 12.14, 13.55, and 11.36 milligrams CO(2) per square decimeter per hour. Chlorophyll in seedlings and plantlets was significantly higher in low light-treated plants. Seedling leaves had chloroplasts with abundant starch regardless of light pretreatment. In high light, starch granules were predominant and associated with disrupted granal structure. Low light seedling chloroplasts had smaller starch grains and well-formed grana. In contrast, tissue culture-differentiated leaves were devoid of starch; grana were well organized in higher quantum flux density treatments, but disorganized at low flux densities.

Journal Article↗