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PubMed1971

Temperature and enzyme activity in poikilotherms. Isocitrate dehydrogenases in rainbow-trout liver.

1. The kinetics of the thermally induced enzyme variants of the supernatant NADP-isocitrate dehydrogenase from rainbow-trout liver are investigated. 2. Fish acclimatized to 2 degrees C (cold-adapted enzyme) and 17 degrees C (warm-adapted enzyme) show different relative distributions of the three NADP-isocitrate dehydrogenase isoenzymes; this has been demonstrated with electrophoresis and electrofocusing techniques. 3. Plots of K(m) versus temperature for the cold-adapted and warm-adapted enzyme variants are complex in nature with apparent maximal enzyme-substrate affinity corresponding to the temperature at which the trout is acclimatized. Both substrates, dl-isocitrate and NADP(+), give similar curves although the magnitude of the K(m) change with temperature is much decreased in the case of NADP(+). 4. E(a) values of approx. 18kcal/mol were determined for both the cold-adapted and warm-adapted enzyme variants. 5. In an attempt to determine how velocities can be increased at low temperatures, cation, pH requirements, metabolite and enzyme concentrations were examined. 6. NAD-isocitrate dehydrogenase could not be detected in trout tissues.

Acclimatization↗
PubMed1994

Cold exposure induces different uncoupling-protein thermogenin masking/unmasking processes in brown adipose tissue depending on mitochondrial subtypes.

The effect of cold exposure on thermogenic parameters such as mitochondrial protein content, GDP-binding and uncoupling protein (UCP) levels in different mitochondrial fractions from rat brown adipose tissue has been investigated. Rats were exposed from 12 h to 5 days at 4 degrees C, and three mitochondrial fractions were isolated by differential centrifugation: the M1 fraction (1000 g), the M3 fraction (3000 g) and the M15 fraction (15,000 g). Cytochrome c oxidase activity as an index of mitochondrial mass showed an increase during cold exposure. During the first 24 h of cold exposure UCP was incorporated specifically into the M3 and M15 mitochondrial fractions, and thereafter UCP appeared in the heaviest M1 fraction. However, specific GDP binding was increased during the first 24 h in the same way in all subpopulations, and this increase continued up to 72 h of cold exposure. Results suggest that different molecular events are involved during acute and chronic adaptation to cold: during the first 24 h of cold acclimatization, thermogenic activity is increased by an unmasking process of the UCP binding sites in the M1 mitochondrial fraction as UCP levels were constant and GDP binding increased, but in the M3 and M15 fraction the increase in thermogenic activity was completely due to an increase in GDP binding induced by a specific incorporation of UCP targeted to these mitochondria. Thus thermogenic parameters change in a different way in the brown-fat mitochondrial subpopulations during cold acclimatization.

Acclimatization↗
PubMed2004

Intermittent altitude exposures reduce acute mountain sickness at 4300 m.

Acute mountain sickness (AMS) commonly occurs at altitudes exceeding 2000-2500 m and usually resolves after acclimatization induced by a few days of chronic residence at the same altitude. Increased ventilation and diuresis may contribute to the reduction in AMS with altitude acclimatization. The aim of the present study was to examine the effects of intermittent altitude exposures (IAE), in combination with rest and exercise training, on the incidence and severity of AMS, resting ventilation and 24-h urine volume at 4300 m. Six lowlanders (age, 23 +/- 2 years; body weight, 77 +/- 6 kg; values are means +/- S.E.M.) completed an Environmental Symptoms Questionnaire (ESQ) and Lake Louise AMS Scoring System (LLS), a resting end-tidal partial pressure of CO2 ( PETCO2) test and a 24-h urine volume collection at sea level (SL) and during a 30 h exposure to 4300 m altitude-equivalent (barometric pressure=446 mmHg) once before (PreIAE) and once after (PostIAE) a 3-week period of IAE (4 h.day(-1), 5 days.week(-1), 4300 m). The previously validated factor score, AMS cerebral score, was calculated from the ESQ and the self-report score was calculated from the LLS at 24 h of altitude exposure to assess the incidence and severity of AMS. During each IAE, three subjects cycled for 45-60 min.day(-1) at 60-70% of maximal O2 uptake (VO2 max) and three subjects rested. Cycle training during each IAE did not affect any of the measured variables, so data from all six subjects were combined. The results showed that the incidence of AMS (%), determined from both the ESQ and LLS, increased (P<0.05) from SL (0 +/- 0) to PreIAE (50 +/- 22) at 24 h of altitude exposure and decreased (P<0.05) from PreIAE to PostIAE (0 +/- 0). The severity of AMS (i.e. AMS cerebral symptom and LLS self-report scores) increased (P<0.05) from SL (0.02 +/- 0.02 and 0.17 +/- 0.17 respectively) to PreIAE (0.49 +/- 0.18 and 4.17 +/- 0.94 respectively) at 24 h of altitude exposure, and decreased (P<0.05) from PreIAE to PostIAE (0.03 +/- 0.02 and 0.83 +/- 0.31 respectively). Resting PETCO2 (mmHg) decreased (i.e. increase in ventilation; P<0.05) from SL (38 +/- 1) to PreIAE (32 +/- 1) at 24 h of altitude exposure and decreased further (P<0.05) from PreIAE to PostIAE (28 +/- 1). In addition, 24-h urine volumes were similar at SL, PreIAE and PostIAE. In conclusion, our findings suggest that 3 weeks of IAE provide an effective alternative to chronic altitude residence for increasing resting ventilation and reducing the incidence and severity of AMS.

Acclimatization↗
PubMed1998

Effect of temperature on the pharmacokinetics of benzocaine in rainbow trout (Oncorhynchus mykiss) after bath exposures.

The pharmacokinetics of benzocaine during bath exposures at 1 mg/L were determined in rainbow trout acclimated at 6 degrees C, 12 degrees C or 18 degrees C for at least 1 month. Individual fish were exposed to benzocaine in a recirculating system for 4 h and pharmacokinetic parameters were estimated in a unique manner from the concentration of benzocaine in the bath water vs. time curve. Elimination from plasma was also determined after the 4 h exposure. The uptake clearance and metabolic clearance increased with increased acclimatization temperatures (uptake clearance 581 +/- 179 mL/min/kg at 6 degrees C and 1154 +/- 447 mL/min/kg at 18 degrees C; metabolic clearance 15.2 +/- 4.1 mL/min/kg at 6 degrees C and 22.3 +/- 4.2 mL/min/kg at 18 degrees C). The apparent volume of distribution had a trend for increasing with temperature that was not significant at the 5% level (2369 +/- 678 mL/kg at 6 degrees C to 3260 +/- 1182 mL/kg at 18 degrees C). The elimination half-life of benzocaine in plasma was variable and did not differ significantly with temperature (60.8 +/- 30.3 min at 6 degrees C to 35.9 +/- 13.0 min at 12 degrees C). Elimination of benzocaine from rainbow trout is relatively rapid and even more rapid at higher acclimatization temperatures based on calculated metabolic clearances and measured plasma concentrations, but was not evident by measurement of terminal plasma half-lifes.

Acclimatization↗
PubMed2001

Redistribution of pulmonary blood flow during hypoxic exercise.

Pulmonary blood flow (PBF) distribution was studied at rest and during exercise in rats acclimatized to chronic hypoxia (barometric pressure [PB] 370 Torr for 3 weeks, A rats) and non-acclimatized (NA) littermates. Both A and NA rats exercised in hypoxia (inspired O2 pressure [PIO2] approximately 70 Torr) or in normoxia (PlO2 approximately 145 Torr). PBF distribution was determined using fluorescent-labeled microspheres injected into the right atrium. The lungs were cut into 28 samples to determine relative scatter of specific PBF ([sample fluorescence intensity/sample dry weight)/(total lung fluorescence intensity/total lung dry weight]). Exercise produced redistribution of PBF both in NA and A rats, and this effect was larger in hypoxia than in normoxia, with minimal redistribution occurring during normoxic exercise in NA rats. The pattern of distribution varies considerably among individual animals. As a result of distribution, the previous high flow areas would be overperfused during hypoxic exercise in some rats. The results support the concept that hypoxic pulmonary vasoconstriction is not uniform and suggest that the combination of hypoxia and exercise may lead to overperfusion and capillary leak in some individuals.

Acclimatization↗
PubMed2003

Arbuscular mycorrhizal inoculation enhances survival rates and growth of Micropropagated plantlets of Echinacea pallida.

In an attempt to induce positive effects on the acclimatization of in vitro propagated Echinacea pallida, four arbuscular mycorrhizal (AM) fungi, Glomus mosseae, Gigaspora ramisporophora, Scutellospora fulgida and Entrophospora colombiana were selected to aid the soil adaptation process. Fungal inocula affected the survival of E. pallida plantlets ranging from 83 % to 92 %, depending on the AM species and also contrasting with 58 % survival of the non-inoculated plantlets. Growth and development were faster in mycorrhizal treated plantlets than in non-treated ones, especially among those treated with Glomus mossae and Scutellospora fulgida. The presence of well-formed arbuscules and vesicles in Echinacea infested roots was confirmed by microscopic examinations in addition to 90 % success in the survival rate of vigorous plants indicated that mycorrhization is a valuable tool to overcome Echinacea acclimatization shock.

Acclimatization↗
PubMed2006

Carbohydrate supplementation and endurance performance of moderate altitude residents at 4300 m.

Recent work from our laboratory demonstrated that carbohydrate supplementation (CHOS) during exercise improved prolonged time-trial (TT) performance of sea-level residents (SLR) living at 4300 m while they were in daily negative energy balance (- 1250 kcal x day (-1); [ ]). The purposes of the current study were to determine during initial exposure to 4300 m:1) whether CHOS also improves TT performance of moderate altitude residents (MAR) who are in energy balance and 2) if acclimatization to moderate elevations benefits TT performance. Fifteen Air Force Academy (AFA) active duty members (age: 30 +/- 1 yrs; mean +/- SE), who had been living at approximately 2000 m for 21 +/- 3 months performed a maximal-effort 720-kJ cycle TT at the AFA and at Pikes Peak (PP), CO, (4300 m) on days 1 (PP1) and 3 (PP3). Daily energy intake and expenditure were maintained similarly at the AFA and PP. At the start of the TTs at PP, and then every 15 min thereafter, 9 subjects drank a 10 % CHO solution (0.175 g x kg (-1) body weight) and 6 subjects drank a placebo (PLA) solution. All subjects were allowed to freely adjust the power output of the cycle ergometer and drank water AD LIBITUM. Performance time did not differ between groups on PP1 (CHOS vs. PLA; 101 +/- 8 vs. 116 +/- 10 min) or PP3 (95 +/- 8 vs. 107 +/- 12 min). For both groups, cycle times on PP1 and PP3 were longer compared to the AFA (p<0.01) and were improved from PP1 to PP3 (p<0.05). Exercise intensity (i.e., % peak oxygen uptake) was maintained similarly at approximately 62 % during the TTs at the AFA and PP. Blood glucose was 1.5 to 2.0 mmol x L (-1) higher for CHOS vs. PLA (p<0.01). It was concluded that CHOS provided no TT performance benefit for MAR at 4300 m when energy balance was maintained. However, the decrements in TT performance and exercise intensity were attenuated at 4300 m in MAR compared to those of SLR as a result of acclimatization attained while living for nearly 2 years at approximately 2000 m.

Acclimatization↗
PubMed1993

Carbohydrate metabolism during exercise in hot and thermoneutral environments.

This study compared the effects of moderately intense exercise in hot and thermoneutral environments on muscle glycogen and carbohydrate utilization. Well-trained, heat acclimatized cyclists (n = 7) rode at 73.6 +/- 1.1% maximal oxygen consumption for 60 min in a thermoneutral room (23.5 +/- 0.6 degrees C, 52.7 +/- 2.9 relative humidity) or an environmental chamber (33.7 +/- 0.1 degrees C, 49.1 +/- 1.8% relative humidity). During each exercise bout, the subjects received 125 ml of water every 15 min. Muscle biopsies from the vastus lateralis were obtained prior to and following each exercise bout. Exercise in the heat significantly elevated rectal temperature and heart rate above and reduced body weight and plasma volume below that produced by exercise in a thermoneutral environment. Plasma glucose and blood lactate concentrations were similar between treatments prior to exercise, but increased to a greater concentration (p < 0.05) when exercise was performed in the heat. No differences between treatments were found for blood glycerol or free fatty acid concentrations, carbohydrate oxidation or muscle glycogen utilization. These results suggest that moderately intense exercise in the heat, as opposed to a thermoneutral environment, does not increase the rate of muscle glycogenolysis or carbohydrate oxidation in well conditioned, heat acclimatized subjects.

Acclimatization↗
PubMed1992

Sleep apneas and high altitude newcomers.

Sleep and respiration data from two French medical high altitude expeditions (Annapurna 4,800 m and Mt Sajama 6,542 m) are presented. Difficulties in maintaining sleep and a SWS decrease were found with periodic breathing (PB) during both non-REM and REM sleep. Extent of PB varied considerably among subjects and was not correlated to the number of arousals but to the intercurrent wakefulness duration. There was a positive correlation between the time spent in PB and the individual hypoxic ventilatory drive. The relation between PB, nocturnal desaturation, and mountain sickness intensity are discussed. Acclimatization decreased the latency toward PB and improved sleep. Hypnotic benzodiazepine intake (loprazolam 1 mg) did not worsen either SWS depression or apneas and allowed normal sleep reappearance after acclimatization.

Acclimatization↗
PubMed1990

The energetic significance of lactate accumulation in blood at altitude.

The O2 equivalent of lactic acid accumulation in blood was estimated from data on ten subjects acclimatized to altitudes up to 6500 m in the course of a Mt. Everest expedition. The calculated value of the O2 equivalent of La by standard least squares regression was 2.07 +/- 0.4 l O2 for a rise of blood lactic acid concentration [Lab] of 1 g per liter of blood (2.92 ml O2 per kg of body weight per 1 mM increase in blood lactate). This value, as well as the value obtained by the regression procedure suggested by Brace (2.84 +/- 0.5 l), was not significantly different from the previously reported value of 2.38 +/- 0.22 (14) for sea-level conditions. This finding indicated that, after La equilibrium is achieved, the redistribution of La among extra- and intracellular body compartments, as reflected by [Lab], appears not to be substantially affected by chronic hypoxia. The calculated maximum lactic O2 debt values at the Mt. Everest base camp (5350 m) were 1.26 and 1.42 liters for acclimatized Caucasians and for Sherpas, respectively. The amount of the measured maximum O2 debt at altitude was somewhat increased by pure O2 breathing (1.53 vs 1.26 l).

Acclimatization↗
PubMedDate not supplied

Short-term effects of formaldehyde on peak expiratory flow and irritant symptoms.

The authors studied the respiratory effects of formaldehyde exposure among students who dissected cadavers in a gross anatomy laboratory. Peak expiratory flow and respiratory symptoms were measured before and after each weekly laboratory session. Each of 38 students was exposed to formaldehyde for 2.5 hr/wk for 14 wk. Individual, daily formaldehyde measurements averaged 1.1 ppm (standard deviation = 0.56 ppm). Multivariate models demonstrated two different time scales of effect of formaldehyde on peak expiratory flow: (1) exposure during the previous 2.5 hr reduced peak expiratory flow by -1.0% per ppm, and (2) average exposure during all preceding weeks reduced peak expiratory flow by an additional -0.5% per ppm of formaldehyde. However, the short-term exposure effect was diminished during the first 4 wk, suggesting at least partial acclimatization. Symptom reporting was also associated with exposure during the previous 2.5 hr, and similar evidence of acclimatization was observed. These results suggest that there are two different time scales of response to formaldehyde, and they emphasize the need for longitudinal studies, characterized by quantitative exposure characterization, and frequent measurements of outcome.

Acclimatization↗
PubMedDate not supplied

Plasma thyroid hormone concentrations in a wintering passerine bird: their relationship to geographic variation, environmental factors, metabolic rate, and body fat.

Winter acclimatization among passerine birds involves metabolic adjustments that allow for high rates of thermogenesis. In previous studies, we observed geographic variation in the basal metabolic rate (BMR) of overwintering cardinals along a latitudinal gradient at two different longitudinal transects. Because thyroid hormones (THs) are important for metabolic adjustments in endotherms, we determined whether geographic variation in BMR can be explained by variation in thyroid status. We measured total plasma TH (thyroxine [T(4)] and 3,5,3'-triiodothyronine [T(3)]) concentrations by radioimmunoassay in birds from two latitudinal transects extending from approximately 31 degrees to 42 degrees. Birds from both transects had higher plasma THs in the late afternoon than in the early morning. Plasma T(3) increased with latitude, while plasma T(4) varied such that the southernmost birds and the northernmost birds had higher hormone concentrations than birds at the intermediate latitude. There was no correlation between plasma TH concentrations and BMR. To test whether thyroid status influences metabolic parameters in winter-acclimatized captive cardinals, we fed cardinals diets supplemented with T(4) (5 microg T(4) g(-1) food), the goitrogen methimazole (1 mg g(-1) food), or both. Plasma T(4) concentrations were altered by most of the treatments, but we observed no significant effects on any metabolic parameter. We conclude, therefore, that there is latitudinal variation in metabolic parameters in cardinals but that this variation is not explained by variation in plasma TH concentrations.

Acclimatization↗
PubMed2005

Temperature influences whole-animal rates of metabolism but not protein synthesis in a temperate intertidal isopod.

The effects of temperature on two important biological rate processes, whole-body rates of oxygen uptake (M dot o2) and protein synthesis (k(s)), were investigated in the temperate intertidal isopod Ligia oceanica at two different times of the year. Animals were collected in January (winter) and June (summer) and either subjected to an acute temperature change after 24 h (acclimatized) or acclimated to various temperatures for 4 wk. In both cases, M dot o2 increased with temperature, with a Q(10) of 2.2 between 5 degrees and 20 degrees C, but increased in thermal sensitivity at 25 degrees C. Winter isopods were characterized by significantly higher M dot o2 levels, greater thermal sensitivities, and lower thermal tolerances than summer animals. Seasonal differences in M dot o2 persisted after acclimation, indicating that temperature alone was not responsible for the changes. In sharp contrast, whole-body k(s) showed no variation with temperature, although overall rates decreased upon acclimation. In acclimatized animals, k(s) was higher in the summer than in the winter. After acclimation, a compensatory increase in RNA capacity in winter animals reversed this situation. The temperature independence of whole-body k(s) in L. oceanica could ensure survival in a highly liable thermal environment, as thermal tolerances of intertidal invertebrates are thought to be more closely related to protein than to energy metabolism.

Acclimatization↗
PubMed2000

Altered structure and function of the carotid body at high altitude and associated chemoreflexes.

The ventilatory response to hypoxia is complex. First contact with hypoxia causes an increase in ventilation within seconds that reaches full intensity within minutes because of an increase in carotid sinus nerve (CSN) input to the brain stem. With continued exposure, ventilation increases further over days (ventilatory acclimatization). Initially, it was hypothesized that ventilatory acclimatization arose from a central nervous system (CNS) mechanism. Compensation for alkalosis in the brain and restoration of pH in the vicinity of central chemoreceptors was believed to cause the secondary increase in ventilation. However, when this hypothesis could not be substantiated, attention was turned to the peripheral chemoreceptors. With the lowering of arterial PO2 at high altitude, there is an immediate increase in firing of afferents from chemoreceptors in the carotid body. After peaking over the next few minutes, the firing rate of afferents begins to rise again within hours until a steady state is reached. This secondary increase occurs along with increase in neurotransmitter synthesis and release and altered gene expression followed by hypertrophy of carotid body glomus cells. Further exposure to hypoxia eventually leads to blunting of the CSN output and ventilatory response in some species. This mini review is about the altered structure and function of the carotid body at high altitude and the associated blunting of the chemoreceptor and ventilatory responses observed in some species.

Acclimatization↗
PubMed2002

Chilean miners commuting from sea level to 4500 m: a prospective study.

The development of mining activities in North Chile involves a great number of workers intermittently exposed to high altitude for a long period of time (chronic intermittent hypoxia, CIH). A 2(1/2)-year prospective study aimed to characterize this model of exposure to CIH and to know whether this condition may progressively lead to a chronic pattern. Twenty-nine miners, aged 25 +/- 5 yr, working 7 days at HA (3800 to 4600 m) and resting 7 days at sea level (SL) were studied. Subjects underwent a physical examination, EKG, hematological status, maximal exercise test, ventilatory and cardiac response to hypoxia (F(iO2) = 0.114) at rest and exercise, pulmonary vascular response to hypoxia by echocardiography, and 24-h monitoring of EKG and arterial pressure. Basal evaluations were performed at SL before the first exposure to hypoxia. HA measurements were daily AMS score, sleep status, and 24-h monitoring of EKG and arterial pressure. All these measurements were repeated after a mean period of 12, 19, and 31 months. Hematocrit increased but reached values lower than those observed in chronic permanent exposure. Systemic and pulmonary arterial pressures measured at SL did not change, but were higher in hypoxia. Right ventricle showed a slight dilatation. Exercise performance at SL declined with exposure to CIH to reach a 12.3% decrease after 31 months of CIH, associated with a 6.8% decrease in maximal heart rate. Signs of ventilatory acclimatization were observed after 12 months. Symptoms of AMS and sleep disturbances were still seen on the first 2 days at HA, whatever the time of exposure to CIH. In conclusion, CIH induced a clear acclimatization process. Subjects did not reach a health status comparable to that seen in permanent residents at HA and remained at risk of acute altitude-induced illnesses.

Acclimatization↗
PubMed2005

Effects of intermittent hypoxia on heart rate variability during rest and exercise.

Changes in heart rate variability induced by an intermittent exposure to hypoxia were evaluated in athletes unacclimatized to altitude. Twenty national elite athletes trained for 13 days at 1200 m and either lived and slept at 1200 m (live low, train low, LLTL) or between 2500 and 3000 m (live high, train low, LHTL). Subjects were investigated at 1200 m prior to and at the end of the 13-day training camp. Exposure to acute hypoxia (11.5% O(2)) during exercise resulted in a significant decrease in spectral components of heart rate variability in comparison with exercise in normoxia: total power (p < 0.001), low-frequency component. LF (p < 0.001), high-frequency component, HF (p < 0.05). Following acclimatization, the LHTL group increased its LF component (p < 0.01) and LF/HF ratio during exercise in hypoxia after the training period. In parallel, exposure to intermittent hypoxia caused an increased ventilatory response to hypoxia. Acclimatization modified the correlation between the ventilatory response to hypoxia at rest and the difference in total power between normoxia and hypoxia (r (2) = 0.65, p < 0.001). The increase in total power, LF component, and LF/HF ratio suggests that intermittent hypoxic training increased the response of the autonomic nervous system mainly through increased sympathetic activity.

Acclimatization↗
PubMed2006

Work capacity of permanent residents of high altitude.

Tibetan and Andean natives at altitude have allegedly a greater work capacity and stand fatigue better than acclimatized lowlanders. The principal aim of the present review is to establish whether convincing experimental evidence supports this belief and, should this be the case, to analyze the possible underlying mechanisms. The superior work capacity of high altitude natives is not based on differences in maximum aerobic power (V(O2 peak)), mL kg(-1)min(-1)). In fact, average V (O2 peak) of both Tibetan and Andean natives at altitude is only slightly, although not significantly, higher than that of Asian or Caucasian lowlanders resident for more than 1 yr between 3400 and 4700 m (Tibetans, n = 152, vs. Chinese Hans, n = 116: 42.4 +/- 3.4 vs. 39.2 +/- 2.6 mL kg(-1)min(-1), mean +/- SE; Andeans, n = 116, vs. Caucasians, n = 70: 47.1 +/- 1.7 vs. 41.6 +/- 1.2 mL kg(-1)min(-1)). However, compared to acclimatized lowlanders, Tibetans appear to be characterized by a better economy of cycling, walking, and running on a treadmill. This is possibly due to metabolic adaptations, such as increased muscle myoglobin content and antioxidant defense. All together, the latter changes may enhance the efficiency of the muscle oxidative metabolic machinery, thereby supporting a better prolonged submaximal performance capacity compared to lowlanders, despite equal V(O2 peak). With regard to Andeans, data on exercise efficiency is scanty and controversial and, at present, no conclusion can be drawn as to the origin of their superior performance.

Acclimatization↗
PubMed2006

Methionine-rich storage protein gene in the rice stem borer, Chilo suppressalis, is expressed during diapause in response to cold acclimation.

Gene expressions of acclimatized and non-acclimatized diapausing larvae were examined in Chilo suppressalis using a subtraction technique. A gene encoding a methionine-rich storage protein, CsSP1, was cloned and its complete cDNA sequence was determined. Potentially, CsSP1 encoded a 758-amino acid protein, with a calculated molecular weight of 88.8 kDa. The expression level of CsSP1 was higher in nondiapausing larvae than in diapausing ones. The CsSP1 expression was up-regulated in diapausing larvae when the temperature of cold acclimation was shifted to 5 degrees C. The up-regulated level was maintained at 40 days after incubation at 5 degrees C. In nondiapausing larvae, CsSP1 expression was down-regulated when the temperature was below developmental zero. Involvement of CsSP1 in diapause, cold tolerance acquisition and postdiapause development in C. suppressalis is discussed.

Acclimatization↗