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PubMed1977

The effects of palmitic acid on skeletal muscle mitochondria of cold and warm acclimated rats.

The effects of palmitic acid on skeletal muscle mitochondria isolated from the hind limb muscle of cold and warm acclimated rats were studied. At higher concentrations of the fatty acid, a greater depression of both ADP/O and RCR (respiratory control ratio) was observed in the cold acclimated group. Initial ADP/O and RCC however, were higher in the cold acclimated group. The enhanced sensitivity of skeletal muscle mitochondria of the cold acclimated rat is discussed.

Acclimatization↗

PubMed1977

Increased resistance of chickens to acute aflatoxicosis by acclimation to low environmental temperatures.

Young broiler chickens were acclimated to environmental temperatures of 8, 19 and 30 degrees C for five weeks. After acclimation, the birds were administered a single oral dose of aflatoxin (8 mg./kg. body weight) by crop intubation and subsequent mortality were noted. Birds acclimated to the 8 degrees C. environment were more resistant to acute aflatoxicosis than birds acclimated to the other environments. Transferring birds from one environment to another at the time of aflatoxin administration had no effect on their resistance to aflatoxin.

Acclimatization↗

PubMed2001

Effect of daily versus intermittent exposure on heat acclimation.

In order to compare the effectiveness of a daily to an intermittent acclimation protocol, 14 competitive rowers (mean +/- SD VO2peak = 48 +/- 7 ml x kg x min(-1)) were randomly assigned to either a consecutive (10 consecutive days) or intermittent acclimation group (10 sessions over 3 weeks). For every heat exposure, subjects in each group exercised for 30 min at 70% VO2peak in an environmental chamber set at 38 degrees C and 70% relative humidity. Acclimation state was monitored by measuring heart rate (HR), rectal and skin temperature (Tre and Tsk), ratings of perceived exertion (RPE) and whole body sweat rate (SR) during each heat exposure. Final exercise Tre decreased significantly by 0.6 +/- 0.7 degrees C with intermittent heat exposure but the decrease was significantly larger (p < 0.05) with consecutive day heat exposure (1.0 +/- 0.1 degrees C). Final exercise HR also decreased significantly by 13 +/- 12 bpm (p < 0.05) in the consecutive group, and non-significantly by 5 +/- 13 bpm in the intermittent group. RPE decreased with daily (5 +/- 1, p < 0.05) but did not significantly decrease with intermittent heat exposure (1 +/- 3). Similarly, Tsk significantly decreased with consecutive (0.4 +/- 0.2 degrees C, p < 0.05) but not intermittent exposure (0.2 +/- 0.3 degrees C) and SR did not change in either group. Minimal adaptation occurs with intermittent heat exposure and it appears that daily heat exposure is the most effective acclimation strategy.

Acclimatization↗

PubMed2000

Effect of laboratory acclimation on food and water consumption of pregnant sheep after fetal catheterization.

The objectives of this study were to determine 1) the time required for food and water consumption of late-gestation pregnant sheep to stabilize after a 6- to 7-h shipment by truck and 2) whether the duration of laboratory acclimation altered food and/or water consumption of pregnant sheep after fetal and maternal vascular catheterization. We used a semi-quantitative scale and a retrospective study design to determine food and water consumption as a function of acclimation time in post-shipping and post-surgery animals. These animals had been in our research facility for 2, 3, 4, and 5 or more days prior to surgical catheterization of the fetus and mother. We used a quantitative scale and a prospective study design to determine food and water consumption in post-surgery animals that had been in the laboratory for either 2 or > or = 7 days at the time of surgery. We used two- and three-factor repeated measures analyses of variance to determine the statistical significance of any differences. Although food and water consumption in post-shipping animals were significantly (p < 0.001) lower on day 1 than other days, we attributed this difference to the fact that "day 1" was shorter than 24 hours because the animals arrived in the laboratory at noon. Further, the post-surgery decrease and subsequent recovery in food and water consumption did not depend on the duration of the acclimation prior to surgery. We conclude that differences in pre-surgery, post-transportation acclimation periods ranging from 48 hours to > or = 7 days do not affect post-operative recovery from fetal surgery in sheep.

Adaptation, Physiological↗

PubMed2002

A novel technology for quick acclimation of an anaerobic microbial consortia used for biodegrading teraphthalic acid (TA).

The seed sludge originated from a methane fermentation reactor was enriched and acclimated with TA as sole carbon source under nitrate respiration mode first for 6 week, and then can be turned to methane fermentation conditions. After 6 weeks processing, the specific rate of TA degradation under nitrate respiration mode reached 23.8 mgTA/(L.gVSS), more than two times of that under methane fermentation mode 11.4 mg TA/(L.gVSS). The TA reductive cleavers' population density increased about 6 times and 20 times after 30 days and 90 days acclimation. After a total of 90 days for the enrichment and acclimation, the fermentative bacteria which originally existed in the seed sludge nearly disappeared, and instead of them, the TA reductive and cleaving bacteria group was formed in the new consortia, which was confirmed by the MPN counts and roll tube counts. Compared with the control experiment, the acclimation period can be shortened by about 50%.

Adaptation, Physiological↗

PubMed2003

[Differentially expressed genes associated with cold acclimation].

To investigate the upregulated genes associated with cold acclimation, a cold acclimation model was established based on Balb/C mouse. mRNA of muscle and liver were isolated, and the upregulated genes of these tissues were studied by representational differential analysis (RDA). The upregulated genes then were sequenced and searched by Blast software in GenBank database. The results showed that some genes were upregulated and possibly associated with cold acclimation. Three of these genes, transferrin, fibrinogen B-beta-chains and a new gene fragment (Genbank ID: AF454762), were confirmed to be upregulated by RNA slot-blot analysis. The finding of these genes might contribute to further understanding of the molecular mechanisms of cold acclimation.

Acclimatization↗

PubMedDate not supplied

[Adenosine triphosphatase activity in the organs of the crab Hemigrapsus sanguineus, acclimated to sea water of different salinity].

In crabs acclimated to low salinity, the activity of Na, K-ATPase from the gills increases; the activity also increases in the antennal glands after acclimation of the animals to high salinity. The activity of Na, K-ATPase in the abdominal ganglion and in the heart does not depend on the salinity to which crabs had been acclimated. Changes in the activity of Mg-ATPase in the gills and antennal glands associated with acclimation of crabs to sea water with different salinity correspond to those in the activity of Na, K-ATPase.

Adaptation, Physiological↗

PubMed1985

Effects of temperature acclimation on rabbit metabolic rate and rectal temperature.

The metabolic rates and rectal temperatures of cold-(10 degrees C), warm-(20 degrees C) and heat-(30 degrees C) acclimated rabbits were measured at 10, 20 and 30 degrees C. When the logarithm of metabolic rate was plotted against the logarithm of body weight, no differences could be demonstrated between the slopes of the lines obtained for each of the nine experimental groups. Metabolic rate, expressed as kcal h-1 kg-1, kcal h-1 kg-3/4 and kcal h-1 kg-2/3, was mass-independent for most of the experimental conditions. The rabbits were able to maintain constant rectal temperature during cold or heat exposure only when previously acclimated to these temperature extremes. The increase in metabolic rate of cold-acclimated rabbits observed during cold exposure seemed to be too low to explain the maintenance of rectal temperature. The lower metabolic rate of heat-acclimated rabbits exposed to heat probably played an important role in preventing increased rectal temperatures.

Acclimatization↗

PubMed1984

Hypohydration and acclimation: effects on hormone responses to exercise/heat stress.

This study was designed to assess the effects of hypohydration (-5% body weight) and heat acclimation on plasma cortisol (PC) and growth hormone (GH) responses to exercise (1.34 m X s-1) in a hot-wet (35 degrees C, 79% rh) or hot-dry (49 degrees C, 20% rh) environment. Preacclimation, hypohydration in both the hot-wet and hot-dry environments resulted in significant (p less than 0.05) increments in PC levels during the fourth exercise interval. Acclimation had no effects on PC levels in the euhydrated condition, but in the hot-wet environment there did occur an attenuation of the PC response when hypohydrated. Preacclimation exercise in either the hot-wet or hot-dry environment resulted in significant (p less than 0.05) increments in GH when euhydrated. While the effects of acclimation were inconsistent, hypohydration generally resulted in elevated levels of GH compared to euhydration. We concluded from these studies that hypohydration to -5% of body weight generally elicited elevations in circulating levels of stress hormones, and that acclimation did not effect consistent decrements in these responses.

Acclimatization↗

PubMed1981

[Effect of temperature acclimation on plasma high density lipoprotein in rats (author's transl)].

Effect of temperature acclimation to cold as well as heat on plasma high-density lipoprotein cholesterol (HDL) was investigated in rats. Cold acclimation (5 degrees C, 4 weeks) caused significant increase in plasma HDL, while heat acclimation (34 degrees C, 4 weeks) caused significant decrease in plasma HDL. Noradrenaline treatment (50 micrograms/100 g, sc., 2 times a day) did not affect plasma HDL level. These results indicate that temperature acclimation could influence HDL metabolism, possibly not via noradrenaline.

Acclimatization↗

PubMed1976

[Influence of the acclimation temperature on the phospholipid metabolism of the fresh water ell (Anguilla anguilla) (author's transl)].

Lowering of the acclimation temperature of the eel induced a reduction of 32P incorporation into the lipid phosphorus of various tissues. This effect was partly the result of a slight decrease of the inorganic phosphate exchange and metabolism of tissues. 2. The variation of the 32P incorporation into the various phosphatides was different according to the tissue ; gill and kidney phospholipids being the most effected. At high temperature (22 degrees C), the turnover of sphingomyelin and phosphatidyl-choline was four or seven fold higher in all tissues than at low temperature. At low temperature (12 degrees C), the incorporation of 32P into gill and kidney phosphatidylinositol and gill diphosphatidyl-glycerol was the same as at high temperature. The kidney diphosphatidyl-glycerol turnover was affected to the same extent as the other phosphatides by high acclimation temperature. The gill phosphatidyl-ethanolamines had a relatively higher turnover at low temperature. 3. The acclimation of the eel at low temperature provoked an increase of the turnover of phosphatidyl-ethanolamine and diphosphatyl-glycerol into the gill, parallel with an increase of some enzymatic activities. 4. The variation of the acclimation temperature may impose restrictions on the turnover of some phosphatides. There is a limited action of the temperature on the turnover of metabolically active phosphatides of the osmoregulatory organs, such as gill phosphatidyl-inositol and diphosphatidyl-glycerol or kidney phosphatidyl-inositol. 5. The significance of these findings is discussed in relation to the role of phospholipids in the cell and to the physiological functions of the various organs of the eel.

Anguilla↗

PubMed1997

Lectin binding pattern and band 3 localization in toad skin epithelium and the effect of salt acclimation.

Seven lectins were employed to localize glycoconjugates in the skin of a toad (Bufo viridis). Each of the lectins exhibited a particular, specific and selective binding pattern. Peanut lectin (PNA) and WGA bound to mitochondria-rich (MR) cells, but WGA bound also abundantly, in the dermis. Band 3-like protein, as indicated by the reaction with polyclonal anti band 3 antibody, was localized exclusively in MR cells. Ionic acclimation (200 mmol/L NaCl, or 50 mmol/L KCl) affected profoundly the binding pattern of the lectins. High NaCl acclimation resulted also in diminishing anti band 3 antibody binding, whereas in skins of KCl-acclimated toads the staining remained similar to the control. The binding of WGA but not PNA, corresponded with the same cells that stained with anti band 3 antibody. PNA in concentration of > 10 micrograms/mL reduced reversibly, both the resting and activated Cl- conductance by 25-30%. Based on differential binding of band 3, WGA and PNA, these observations provide conclusive verification of the presence of at least two populations of MR cells in the toad skin epithelium. It is suggested that the PNA positive MR cells may correspond to a beta-type MR cell. The information can be used to study molecular mechanisms that are involved in ionic acclimation.

Adaptation, Physiological↗

PubMed1998

Efficient rooting and acclimation of micropropagated Ruppia maritima Loisel.

An efficient protocol for rooting and acclimation of in vitro propagated Ruppia maritima was the focus of this research. The effects of four dilutions of a nutrient medium (f) and four different concentrations of sodium bicarbonate on rooting production were investigated. The optimal rooting medium was determined to be f/2 with 0.25 mM sodium bicarbonate in 5 ppt synthetic seawater at a pH of 7.5. Cultures of R. maritima were found to be photosynthetically inactive as measured by oxygen evolution in sucrose-based multiplication medium but were physiologically capable of adjusting to autotrophism once transferred to a bicarbonate medium. This transition was immediate and comparable to cultures that had acclimated in bicarbonate-based medium for 21 days. Ruppia maritima rooted onto coconut fiber mats and unanchored plants were acclimated in outdoor aquaria during May 1995. The results of these studies showed that micropropagated R. maritima can be acclimated easily and effectively at a low cost in aquaria, making R. maritima a useful seagrass species for restoration and mitigation projects.

Journal Article↗

PubMed1999

Ultracytochemical location of Na(+)/K(+)-atpase activity and effect of high salinity acclimation in gill and renal epithelia of the freshwater shrimp Macrobrachium olfersii (Crustacea, Decapoda).

Accumulation sites of lead phosphate reaction product consequent to Na(+)/K(+)-ATPase activity in gill and renal epithelia of the freshwater shrimp Macrobrachium olfersii were located ultracytochemically by para-nitrophenyl-phosphate hydrolysis and lead precipitation, and quantified per unit membrane area and cytoplasmic volume. In shrimps in freshwater (<0.5 per thousand S, 20 mOsm/kg H(2)O, 0.7 mEq Na(+)/liter), numerous sites of electron-dense, Na(+)/K(+)-ATPase reaction product accumulation were demonstrated in the membrane invaginations of the mitochondria-rich, intralamellar septal cells (12.5 +/- 1.7 sites/microm(2) membrane, 179 +/- 22 sites/microm(3) cytoplasm, mean+/- SEM, N </= 7) and in the basal region of the medial renal tubules (19.8 +/- 1.8 sites/microm(2) membrane, 437 +/- 53 sites/microm(3) cytoplasm), but not in the pillar cells whose apical flanges form the primary interface with the external medium. A putative, ouabain-insensitive Na(+)- or H(+)-ATPase was found in the apical microvilli of the medial renal tubules (17.4 +/- 1.7 sites/microm(2) membrane, 629 +/- 101 sites/microm(3) cytoplasm). This restricted location of Na(+)/K(+)-ATPase activity within the gill epithelium suggests that during uptake, Na(+) moves across the apical pillar cell membrane, passes through specialized, basolateral coupling junctions into the septal cell cytoplasm and is pumped into the hemolymph via the Na(+)/K(+)-ATPase in the invagination membranes. In shrimps acclimated to a high-salinity medium (21 per thousand S, 630 mOsm/kg H(2)O, 280 mEq Na(+)/liter) for 2 and 5 days, the mean number of sites of para-nitrophenylphosphatase activity/microm(2) membrane and /microm(3) cytoplasm for both epithelia increases markedly by 83 and 163%, respectively. However, after 10 days acclimation, the number of sites declines dramatically, attaining values far below those for shrimps in freshwater. These acclimation-induced alterations in numerical density/microm(3) cytoplasm cannot be accounted for by corresponding changes in membrane surface density (microm(2) membrane/microm(3) cytoplasm) and reflect a real alteration in the number of Na(+)/K(+)-ATPase reaction product sites/unit membrane area. These data suggest that neither the gill nor the renal Na(+)/K(+)-ATPase systems function at maximal activity in shrimps in freshwater, possibly due to the low Na(+) concentration, and are initially stimulated by the increase in external ionic concentration. However, these powerful Na(+) transport systems respond to salt loading by a notable reduction in the number of hydrolysis sites, possibly through the incorporation of the Na(+)/K(+)-ATPase into isolated membrane vesicles in the basal invaginations of the medial renal tubules, together with ultrastructural alterations like the spatial isolation of the mitochondria by multiple membrane stacks in the intralamellar septal cells. J. Exp. Zool. 284:617-628, 1999.

Adaptation, Physiological↗

PubMed2001

Influence of anaerobic culture acclimation on the degradation kinetics of various substrates.

The adaptation of an anaerobic culture (anaerobic sludge) to a specific substrate brings significant changes to its microbial population. These changes can be described by the sludge's ability to treat various substrates such as carbohydrates or proteins or "intermediate" products of anaerobic metabolism such as L-lactic, propionic, and acetic acids. The activity of the sludge with respect to a specific substrate is a critical parameter, because the anaerobic degradability of wastewaters depends strongly on it. This work examines and quantifies the differentiation of two anaerobic sludges of the same origin, following an adaptation period of about 18 months to lactose and gelatin, respectively. The acclimation has a significant effect on the maximum specific utilization rates of various compounds and on their apparent consumption kinetics. It is noticeable, however, that even if the anaerobic cultures were not exposed to a specific substrate for a prolonged period of time (more than a year), they still kept the ability of hydrolyzing or degrading it. In addition, the acclimation has an unquestionable effect on the stoichiometry of the production of volatile fatty acids and L-lactate. Finally, from codigestion experiments it is shown that codigestion of lactose and gelatin appears to have no effect on their hydrolysis kinetics in any of the lactose or gelatin acclimated cultures; specifically, the hydrolysis kinetics remained the same as calculated when lactose or gelatin were the only fed substrates. Similarly, the kinetics of L-lactate and D-glucose biodegradation seemed to be unchanged. On the other hand, codigestion has a significant effect on the production of L-lactic, propionic, and acetic acids, which can be attributed to the increased hydrogen production accompanying gelatin biodegradation.

Acetates↗

PubMed2001

Early carbonic anhydrase induction in the gills of the blue crab, Callinectes sapidus, during low salinity acclimation is independent of ornithine decarboxylase activity.

Carbonic anhydrase (CA) induction in the gills of the euryhaline blue crab, Callinectes sapidus, was measured in response to lowered environmental salinity. Simultaneous measurements of ornithine decarboxylase (ODC) activity were made in gills and nonbranchial tissues to determine whether ODC activity and the resultant synthesis of polyamines played a role in the initiation and regulation of CA induction. CA induction in the seventh gill pair (G7) was proportional to the decrease in ambient salinity, but activity in the third gill pair (G3) remained unchanged. Induction began by 24 hr after low salinity transfer, much earlier than previously reported, and peaked after 4 days. The magnitude of salinity change affected the magnitude of CA induction only, not the time course. A general cell volume regulatory response, as measured by the appearance of total ninhydrin-positive substances (TNPS) in the hemolymph, was initiated within 4 hr of low salinity transfer and was complete by 24 hr post-transfer. General cell swelling may be the initial signal in the pathway of CA induction. ODC activity in the gills of acclimated animals was not influenced by salinity. For crabs transferred from 35 to 25 ppt, ODC activity did not change significantly over the time course of acclimation. There was an early but transient increase in ODC activity in all tissues for crabs acclimated to 28 ppt and transferred to 15 ppt. Induction of ODC activity does not appear to be a precursor for CA induction; therefore, it does not appear that polyamines are substantially involved in the up-regulation of transport enzyme activity in low salinity. ODC, and resultant polyamine synthesis, may, however, have a role in cell volume regulation.

Adaptation, Physiological↗

PubMed1977

Rapid modulation of gill Na+ + K+-dependent ATPase activity during acclimation of the killifish Fundulus heteroclitus to salinity change.

The enzymatic properties of membrane-bound Na+ + K+-ATPase from gills of killifish acclimated to fresh water, to 16% sea water, or to 30% sea water appear to be identical, indicating that the same enzyme may function to absorb Na+ in low salinities and excrete Na+ at the gills in high salinities. Ammonium ion is an effective substitute for K+: in the ATPase reaction itself, in blocking phosphorylation of the ATPase protein, and in inhibiting the binding of ouabain to the enzyme. The specific activities of the Na+ + K+-ATPase in the three different salinities are consistent with the expected Na+ pumping rates: higher in fresh water and 30% sea water than in 16% sea water. Within one-half hour after transfer of killifish from one salinity to another, gill Na+ + K+-ATPase activities reach equilibrium levels. The rapid increase in Na+ + K+-ATPase activity in gill microsomes of fish acclimating from fresh water to 30% sea water is accompanied by a slow decrease in the number of binding sites for ouabain, supporting the idea that acclimation to short-term salinity changes may involve modifications in the catalytic rate rather than the number of Na+ + K+-ATPase molecules.

Acclimatization↗

PubMed1979

Enzyme changes accompanying thermal acclimation in two species of pleurocerid snails.

Goniobasis cahawbensis is a stream snail that experiences an annual temperature cycle. G. cochliaris is limited in distribution to springs, and their immediate vicinities, which are characterized by nearly constant annual temperatures. The present study sought to determine whether temperature dependent biochemical differences exist that might account for the differential distribution of these congeneric pleurocerid snails. Eight enzymes were examined following acclimation to 10 degrees, 17 degrees and 24 degrees C. No significant temperature dependent qualitative differences in enzyme phenotypes were demonstrable in either species by starch-gel electrophoresis for malate dehydrogenase, glucose-6-phosphate dehydrogenase, phosphogluconate dehydrogenase, phosphoglucomutase, superoxide dismutase and acetyl and butyryl esterases. Significant quantitative differences were observed in three of these enzymes. G. cahawbensis cytosol malate dehydrogenase activity increased significantly with increasing acclimation temperature, while G. cochliaris malate dehydrogenase activity remained unchanged. The activities of glucose-6-phosphate dehydrogenase did not differ significantly between acclimation temperatures for either species; however, the overall activity of both enzymes was significantly higher for G. cochliaris. Appreciable levels of LDH activity were not demonstrable by electrophoresis or enzymatic assay.

Adaptation, Physiological↗