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1.
Banana fruit are highly susceptible to chilling injury during low temperature storage. Experiments were conducted to compare ethylene binding during storage at chilling (3 and 8 °C) versus optimum (13 °C) temperatures. The skins of fruit stored at 3 and 8 °C gradually darkened as storage duration increased. This chilling effect was reflected in increasing membrane permeability as shown by increased relative electrolyte leakage from skin tissue. In contrast, banana fruit stored for 8 days at 13 °C showed no chilling injury symptoms. Exposure of banana fruit to the ethylene binding inhibitor 1-methylcyclopropene (1 l l-1 1-MCP) prevented ripening. However, this treatment also enhanced the chilling injury accelerated the occurrence of chilling injury-associated increased membrane permeability. 14C-ethylene release assay showed that ethylene binding by banana fruit stored at low temperature decreased with reduced storage temperature and/or prolonged storage time. Fruit exposed to 1-MCP for 12 h and then stored at 3 or 8 °C exhibited lower ethylene binding than those stored at 13 °C. Thus, chilling injury of banana fruit stored at low temperature is associated with a decrease in ethylene binding. The ability of tissue to respond to ethylene is evidently reduced, thereby resulting in failure to ripen. 相似文献
2.
Effects of 1-MCP and exogenous ethylene on fruit ripening and antioxidants in stored mango 总被引:2,自引:0,他引:2
Baogang Wang Jianhui Wang Xiaoyuan Feng Lin Lin Yumei Zhao Weibo Jiang 《Plant Growth Regulation》2009,57(2):185-192
Mango (Mangifera indica L. cv. Tainong) fruits were harvested at the green-mature stage in Hainan and air-freighted to the laboratory at Peking.
The fruits were treated with either 1 μl l−1 1-MCP or 5 μl l−1 ethylene for 24 h and stored at 20°C for up to 16 days. 1-MCP maintained fruit firmness, whereas exogenous ethylene decreased
fruit firmness. Exogenous ethylene accelerated the increase in ethylene and 1-aminocyclopropane-1-carboxylate (ACC) oxidase,
whereas 1-MCP reduced both. Exogenous ethylene stimulated and 1-MCP inhibited the production of H2O2 of mango fruit during storage. Ascorbic acid was maintained at a high concentration in 1-MCP-treated fruit but was low in
ethylene-treated fruit. 1-MCP inhibited activities of antioxidant enzymes including catalase, superoxide dismutase and ascorbate
peroxidase. These results suggest that 1-MCP could play a positive role in regulating the activated oxygen metabolism balance.
Baogang Wang and Jianhui Wang contributed equally to this work. 相似文献
3.
Kjell Johansen Gunnar Lykkeboe Sonja Kornerup G. M. O. Maloiy 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1980,136(1):71-76
Summary Respiratory gas exchange and blood respiratory properties have been studied in the East-African tree frogChiromantis petersi. This frog is unusually xerophilous, occupies dry habitats and prefers body temperatures near 40°C and direct solar exposure. Total O2 uptake was low at 81 l O2·g–1·h–1±19.0 (SD) at 25°C increasing to 253.5 l O2·g–1·h–1±94.8 (SD) at 40°C giving aQ
10 value of 2.1. Skin O2 uptake at 25°C was 38.5% of total. The gas exchange ratio was 0.71 for whole body gas exchange, 0.61 for the lungs and 1.02 for the skin at 25°C.Blood O2 affinity was low with aP
50 of 47.5 mmHg at 25°C and pH 7.65. Then
H-value at 25°C increased from 2.7 aroundP
50 to 5.0 at O2 saturations exceeding 70–80%. Surprisingly, blood O2 affinity was nearly insensitive to temperature expressed by a H value of ±1.0 kcal·mole between 25 and 40°C.The adaptive significance of the low O2 affinity, the increase ofn
H with O2 saturation and the temperature insensitive O2-Hb binding is discussed in relation to the high and fluctuating body temperatures ofChiromantis. 相似文献
4.
Hans Jürgen Braune 《Oecologia》1976,25(1):77-87
Summary Oxygen consumption at 25°C was measured continously throughout the egg stage of Leptopterna dolobrata (more than 9 months).The rate of O2-uptake (l O2/100 eggs · 1 h) is low in freshly laid eggs. Maintaining the eggs at a constant temperature of 16°C, respiration rises abruptly from the first day after oviposition and continues rising steadily for 3 days, reaching an average value of 1.4 l. Oxygen consumption persists at or near this high level during the developmental phase of prediapause, which lasts about 15 days. After some days of oscillating high and low values, respiration decreases, and from the 24th day a low level (0.3–0.4 l) is reached. If the eggs are incubated at 16°C continuously, this low diapause-level is maintained until the end of the experiments (42 weeks) and diapause is terminated in a few eggs only.A significant increase in the success of hatching is obtained by exposing the eggs to a sufficient period of chilling.24 groups of diapausing eggs were chilled at 5°C for certain periods (10, 18, 22, 26, 31, and 34 weeks) and afterwards transferred to 16°C and re-incubated. The changes of their O2-uptake at 25°C were traced throughout their chilling and successive re-incubating periods.Oxygen consumption is greatly accelerated during the cold treatment of the eggs. The low values of the diapause-level are raised progressively during the first 6 weeks of chilling. After this primary rapid increase, respiration remains at a level 5-times as high as the diapause values over a period up to the 25th week at 5°C. This is almost exactly the duration of mesodiapause (6 months).The rates of O2-uptake during the subsequent re-incubation at 16°C depend on the extent of chilling. The ability of diapause-breaking is correlated to the rates of O2-uptake, measured after setting of re-incubation. If respiration never decreases by the onset of re-incubation, diapause is terminated in most of the eggs, and the rates of O2-uptake increase as re-incubation goes on towards the emergence of the larvae (postdiapause period).A preliminary interpretation of the cold-stimulated O2-uptake in diapausing Leptopterna-eggs is given.Dedicated to Prof. Dr. H. Precht (Kiel) on the occasion of his 65th birthday 相似文献
5.
Ioannis S. Minas Georgia Tanou Afroditi Krokida Evangelos Karagiannis Maya Belghazi Miltiadis Vasilakakis Kalliope K. Papadopoulou Athanassios Molassiotis 《BMC plant biology》2018,18(1):358
Background
Understanding the mechanisms involved in climacteric fruit ripening is key to improve fruit harvest quality and postharvest performance. Kiwifruit (Actinidia deliciosa cv. ‘Hayward’) ripening involves a series of metabolic changes regulated by ethylene. Although 1-methylcyclopropene (1-MCP, inhibitor of ethylene action) or ozone (O3) exposure suppresses ethylene-related kiwifruit ripening, how these molecules interact during ripening is unknown.Results
Harvested ‘Hayward’ kiwifruits were treated with 1-MCP and exposed to ethylene-free cold storage (0?°C, RH 95%) with ambient atmosphere (control) or atmosphere enriched with O3 (0.3?μL?L??1) for up to 6?months. Their subsequent ripening performance at 20?°C (90% RH) was characterized. Treatment with either 1-MCP or O3 inhibited endogenous ethylene biosynthesis and delayed fruit ripening at 20?°C. 1-MCP and O3 in combination severely inhibited kiwifruit ripening, significantly extending fruit storage potential. To characterize ethylene sensitivity of kiwifruit following 1-MCP and O3 treatments, fruit were exposed to exogenous ethylene (100?μL?L??1, 24?h) upon transfer to 20?°C following 4 and 6?months of cold storage. Exogenous ethylene treatment restored ethylene biosynthesis in fruit previously exposed in an O3-enriched atmosphere. Comparative proteomics analysis showed separate kiwifruit ripening responses, unraveled common 1-MCP- and O3-dependent metabolic pathways and identified specific proteins associated with these different ripening behaviors. Protein components that were differentially expressed following exogenous ethylene exposure after 1-MCP or O3 treatment were identified and their protein-protein interaction networks were determined. The expression of several kiwifruit ripening related genes, such as 1-aminocyclopropane-1-carboxylic acid oxidase (ACO1), ethylene receptor (ETR1), lipoxygenase (LOX1), geranylgeranyl diphosphate synthase (GGP1), and expansin (EXP2), was strongly affected by O3, 1-MCP, their combination, and exogenously applied ethylene.Conclusions
Our findings suggest that the combination of 1-MCP and O3 functions as a robust repressive modulator of kiwifruit ripening and provide new insight into the metabolic events underlying ethylene-induced and ethylene-independent ripening outcomes.6.
Previous studies have demonstrated that mature green tomatoes can be stored for up to 10 wk at 12. 5°C, 93–95% r.h. in a controlled atmosphere (CA) containing 5% CO 2 , 5% O2 and 90% N 2 , and will then ripen satisfactorily in air at 20°C. The effects of different concentrations of ethylene between <0.1 and 30 μl/litre in this storage atmosphere on ripening changes and fruit quality after 5 wk CA storage and a further 8 or 9 days ripening in air were investigated using cv. Sonatine glasshouse tomatoes. Maintaining ethylene concentrations in the storage atmosphere to.1 plllitre resulted in poor and uneven ripening of the tomatoes after storage, and increased their susceptibility to infection by Botrytis cinerea and Penicillium spp. Fruit previously stored in atmospheres containing 5 to 30 μl/litre ethylene were significantly softer after ripening than tomatoes stored in lower ethylene concentrations. Overall, the best results in terms of fruit quality (colour, firmness) and a low incidence of fungal infection were achieved with 1–3 μl/litre ethylene. The practical problems in achieving and maintaining optimum conditions, including the correct ethylene level, in CA storage of tomatoes are also discussed. 相似文献
7.
Sorting of an exocrine secretory protein to the regulated secretory pathway in endocrine cells 总被引:3,自引:0,他引:3
The effect of exogenous polyamines on electrolyte leakage, chilling index, polygalacturonase activity (PG), ethylene production, and firmness in zucchini squash fruits stored for 12 days at 2 degrees C or 10 degrees C, 85-90% RH was evaluated. Fruits were infiltrated with putrescine (PUT) spermidine (SPD) and spermine (SPM) at 0.1, 0.25, 0.5, 2.0, and 4.0 mM. All polyamines exerted a protective effect on cell and organelle membranes. The most effective was SPD, which reduced electrolyte leakage between 62% and 82%, compared to control fruits stored at 2 degrees C. At 10 degrees C they did not exhibit chilling injury (CI) symptoms, while at 2 degrees C SPM (0.5 mM) and SPD (0.5 mM) diminished them 92% and 100%, respectively; which extended storage life for 8-10 days at 2 degrees C. High concentrations of polyamines (>2.0 mM) caused the appearance of CI symptoms. PG activity diminished proportionally to the concentration of polyamine except for the concentration at 4.0 mM. No significant changes were observed in ethylene production. 相似文献
8.
Exposure to high O2 concentrations may stimulate, have no effect or retard fruit ripening depending upon the commodity, O2 concentration and storage time among other variables. The ethylene-binding inhibitor 1-methylcyclopropene (1-MCP) was used to investigate ethylene-mediated softening responses of Williams banana fruit exposed to elevated O2 for various periods of time. Fruit softening was measured at 25 °C and 90% relative humidity. Exposure to high O2 concentrations for 5 days resulted in accelerated softening. Softening of fruit treated with 1-MCP for 12 h followed by 5 days of storage in high O2 atmospheres at 25 °C was enhanced with increasing O2 concentration between 21 and 100%. However, overall softening was much less compared to non-1-MCP-treated fruit. Softening of 1-MCP-treated fruit was progressively enhanced with increasing holding time from 5 to 20 days. Fruit treated with 1-MCP and then held for 10 days in high O2 atmospheres followed by exposure to ethylene for 24 h and subsequent storage for 5 days at 25 °C softened more rapidly than those held in air for 10 days. 1-MCP-treated fruit held in various high O2 atmospheres can regain gradually the sensitivity to ethylene and finally ripen over time. Enhanced softening of fruit exposed to elevated O2 concentrations suggests that high O2 treatments enhance synthesis of new ethylene binding sites. 相似文献
9.
D. L. C. Procter 《Polar Biology》1987,7(5):303-306
Summary Respiration of an undescribed species of soil nematode of the genus Chiloplacus from the Canadian High Arctic was measured at 2°, 5°, 10°, 15°, 20° and 25°C. The corresponding metabolic rates were 0.2697×10-3 l, 0.3406×10-3 l, 0.8408×10-3 l, 0.8539×10-3 l, 1.8420×10-3 l and 2.9360×10-3 l O2 ind-1 h-1, respectively, for a nematode of 1.0 g dry weight. The relationship between respiration and dry weight for Chiloplacus sp. at 10°C is described by the function log R=-3.0693+0.8844 log W. Q10 values for the 2°–5°, 5°–10°, 10°–15°, 15°–20° and 20°–25°C temperature intervals were 2.18, 6.09, 1.03, 4.65 and 2.54, respectively. Chiloplacus sp. showed raised metabolic rates at low tempetatures compared with species from warmer environments. Metabolic rates of representative samples of the soil, nematode fauna (dominated by individuals of the genus Plectus) from the same location were 0.1593×10-3 l, 0.3603×10-3 l and 0.5332×10-3 l O2 ind-1 h-1 at 5°, 10° and 15°C for an average nematode of 0.4297 g dry weight. 相似文献
10.
Summary Open-system infra red gas analysis was used to measure the CO2 output throughout a year of four species of earthworm. The respiratory quotients (R.Q.s) of the four species were determined by means of a Warburg apparatus and it was found that they varied with season. In some instances R.Q.s did not fall within the expected range of 0.7 to 1.0 and the low values were attributed to calciferous gland activity and the fixation of metabolic CO2.The results from CO2 output measurements at 10°C and R.Q.s were used to calculate oxygen uptake, this varied seasonally but the mean annual values at 10°C for adult, large immature and small immature A. rosea were 64.17, 72.66 and 78.56 l O2 g-1 fresh wt h-1 respectively. Mixed size groups of L. castaneus had a mean annual oxygen consumption at 10°C of 155.83 l O2 g-1 fresh wt h-1 and equivalent values for D. rubida and O. cyaneum were 112.02 and 69.35 l O2 g-1 fresh wt h-1. The apparent relationship between a high respiratory rate per unit weight and a litter dwelling habit (e.g. L. castaneus and D. rubida) disappeared when allowance was made for the weight of gut contents. Mean annual values for oxygen uptake in l O2 g-1 gut free fresh wt h-1 at 10°C were L. castaneus (194.79), D. rubida (142.22), A. rosea (95.70) and O. cyaneum (139.28). No size specific metabolism could be demonstrated either within or between species, this is believed to be correlated with the different levels of activity shown by different species and their life stages.Rates of oxygen consumption per unit weight for A. rosea were shown to be proportional to ambient temperature. Q
10 slopes of this relation, between 6 and 15°C, were higher for large immature A. rosea (2.42) and small immatures (1.96) than for adult clitellate worms (1.42). The mean Q
10 relationship for all size classes of A. rosea was 1.93 over the same temperature range and the equivalent value for cocoons was 1.63. The relationship between the oxygen consumption rate of all size classes of A. rosea and ambient temperature was not significantly affected by acclimatisation at 5 and 10° C prior to measurements being made at 6, 10 and 15° C. 相似文献
11.
Anne Kathrine Hvoslef-Eide 《Plant Cell, Tissue and Organ Culture》1992,28(2):167-174
In vitro cultures of Nephrolepis exaltata and Cordyline fruticosa were stored at 5°, 9° or 13°C, at a low irradiance (3–5 mol m–2 s–1) or in darkness. Prior to storage the cultures were subjected to 18°, 21°, 24° or 27°C and 15, 30 or 45 mol m–2 s–1 in a factorial combination.The optimal storage conditions for Nephrolepis were 9°C in complete darkness. These cultures were still transferable to a peat/perlite mixture at the end of the experimental period of 36 months.The optimal storage conditions for Cordyline were 13°C and a low light level (±3–5 mol m-2 s-1). When the pre-storage conditions were normal growth room conditions (24°C and 30 mol m-2 s-1), in vitro cultures could be stored for 18 months. With the most favourable pre-storage treatment (18°C and 15 mol m-2 s-1) some cultures still had green shoots after 36 months of storage, but did not survive transfer to peat/perlite.Pre-conditioning before storage was most favourable for Nephrolepis, and not that important, but still favourable, for Cordyline. There was an interaction between pre-storage temperature and pre-storage irradiance. For both species a high irradiance level was less favourable than a low irradiance level when combined with high growth room temperatures.Abbreviations BA
6-benzyladenine
- IAA
indole-3-acetic acid
- NOA
2-naphthoxyacetic acid 相似文献
12.
Johan B. Steen Øivind Tøien Peder Fiske 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1991,161(2):155-158
1. | Physiological adaptation to hypothermia were studied in newly hatched great snipe chicks (Gallinago media) by measuring oxygen uptake (VO2), heart rate (HR), respiratory frequency (RF), and body temperature (Tb) at different ambient temperatures (Ta). |
2. | Tb of 1-day-old chicks at Ta of 35°C stabilized at about 40°C. At Ta between 20 and 30°C the chicks maintained a Tb about 8°C above Ta. Hatchlings maintained a higher gradient when active than when resting. Below 20°C they were unable to maintain a stable Tb. |
3. | In resting hatchlings VO2 was similar at Ta between 35 and 20°C (Tb 40–30°C), VO2 range 1.7–2.5 ml·g-1·h-1. Below 20°C, VO2 declined with time. |
4. | The HR of 1-day-old chicks fell linearly with Tb during cooling. The Q10 of the HR was 1.7 at Tb 38°C and increased to 3.0 at 29°C. The RF showed a slight tendency to decrease with decreasing Tb. |
5. | It is concluded that the ability to maintain normal dexterity at low Tb is an important aspect of snipe survival strategy. Maintaining a temperature gradient rather than a constant high Tb presumably saves energy. It is suggested that the mechanisms whereby VO2 is maintained at a low Tb may involve isoenzymes and adaptations of the nervous system. However, such adaptations would not seem to affect the pacemaker mechanism as evidenced by the high Q10 of the HR. |
13.
S. Marhold A. Nagel 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1995,164(8):636-645
Body temperature, oxygen consumption, respiratory and cardiac activity and body mass loss were measured in six females and four males of the subterranean Zambian mole rat Cryptomys sp. (karyotype 2 n=68), at ambient temperatures between 10 and 35°C. Mean body temperature ranged between 36.1 and 33.2°C at ambient temperatures of 32.5–10°C and was lower in females (32.7°C) than in males (33.9°C) at ambient temperatures of 10°C but dit not differ at thermoneutrality (32.5°C). Except for body temperature, mean values of all other parameters were lowest at thermoneutrality. Mean basal oxygen consumption of 0.76 ml O2·g-1· h-1 was significantly lower than expected according to allometric equations and was different in the two sexes (females: 0.82 ml O2·g-1·h-1, males: 0.68 ml O2·g1·h-1) but was not correlated with body mass within the sexes. Basal respiratory rate of 74·min-1 (females: 66·min1, males: 87·min-1) and basal heart rate of 200·min-1 (females: 190·min-1, males: 216·min-1) were almost 30% lower than predicted, and the calculated thermal conductance of 0.144 ml O2·g-1·h1·°C-1 (females; 0.153 ml O2·g-1·h-1·°C-1, males: 0.131 ml O2·g-1·h-1·°C-1) was significantly higher than expected. The body mass loss in resting mole rats of 8.6–14.1%·day-1 was high and in percentages higher in females than in males. Oxygen consumption and body mass loss as well as respiratory and cardiac activity increased at higher and lower than thermoneutral temperatures. The regulatory increase in O2 demand below thermoneutrality was mainly saturated by increasing tidal volume but at ambient temperatures <15°C, the additional oxygen consumption was regulated by increasing frequency with slightly decreasing tidal volume. Likewise, the additional blood transport capacity was mainly effected by an increasing stroke volume while there was only a slight increase of heart frequency. In an additional field study, temperatures and humidity in different burrow systems have been determined and compared to environmental conditions above ground. Constant temperatures in the nest area 70 cm below ground between 26 and 28°C facilitate low resting metabolic rates, and high relative humidity minimizes evaporative water loss but both cause thermoregulatory problems such as overheating while digging. In 13–16 cm deep foraging tunnels, temperature fluctuations were higher following the above ground fluctuations with a time lag. Dominant breeding females had remarkably low body temperatures of 31.5–32.3°C at ambient temperatures of 20°C and appeared to be torpid. This reversible hypothermy and particular social structure involving division of labour are discussed as a strategy reducing energy expenditure in these eusocial subterranean animals with high foraging costs.Abbreviations BMR
basal metabolic rate
- br
breath
-
C
thermal conductance
- HR
neart rate
- LD
light/dark
-
M
b
body mass
- MR
metabolic rate
- OP
oxygen pulse
- PCO2
partial pressure of carbon dioxide
- PO2
partial pressure of oxygen
- RMR
resting metabolic rate
- RR
respiratory rate
-
T
a
ambient temperature
-
T
b
body temperature
- TNZ
thermal neural zone
-
O2
oxygen consumption 相似文献
14.
P. Newrkla 《Oecologia》1978,33(1):87-99
Summary For A. spinosus, significant correlations were found between population parameters and the ecological parameters of alkalinity and temperature. For the birth rate, 43.33% of variance is explained by alkalinity and 56.33% by alkalinity and temperature. Alkalinity, and alkalinity and temperature combined account for 48.22% and 70.23% respectively of the observed variances in nauplii hatching. It was demonstrated that, provided sufficient time for adaptation is allowed, the activity of individuals is not affected by differences in the alkalinity of the medium within the normal range of concentration. Embryonic development does not appear to be influenced by the ionic concentration, but significant increases in time of development of the nauplii (at alkalinity 100 meq/l: 8.8 days/20°C) and of the copepodites (at alkalinity 100 meq/l: 12.6 days/20°C) were recorded at both low and high ionic concentrations. The lowest respiration rates (3.7 nl O2·h-1·g dw-1/20°C) occurred at an alkalinity of 100 meq/l. Rates increased at lower (10 meq/l: 5.7 nl) and at higher (400 meq/l: 11.9 nl) alkalinities. 相似文献
15.
Calegario FF Cosso RG Fagian MM Almeida FV Jardim WF Jezek P Arruda P Vercesi AE 《Journal of bioenergetics and biomembranes》2003,35(3):211-220
The CO2 evolution of intact potato tubers (Solanum tuberosum, L., var. Bintje) was analyzed during a 10-day period of their warm (25 ± 2°C) or cold (5 ± 1°C) storage, to evaluate cold-stress effects on expression and activities of plant uncoupling mitochondrial protein (PUMP) and alternative oxidase (AOX). CO2 evolution rates were analyzed at 20°C, to reflect their possible capacities. The 20°C CO2 production declined from 13 to 8 mg kg–1 h–1 after 2 days of warm storage and then (after 3 to 7 days) decreased from 8 to 6.5 mg kg–1 h–1. In contrast, 20°C CO2 evolution did not change after the first day of cold storage, increased up to 14.5 mg kg–1 h–1 after 2 days, and decreased to about 12 mg kg–1 h–1 after 3 to 7 days of cold storage. Cold storage increased PUMP expression as detected by Western blots and led to elevated capacities of both PUMP (44%) and CN-resistant AOX (10 times), but not the cytochrome pathway. Since we found that cold storage led to about the same mitochondrial respiration of 40 nmol O2 min–1 mg–1 attributable to each of the respective proteins, we conclude that both AOX and PUMP equally contribute to adaptation of potato tubers to cold. 相似文献
16.
Varda Kagan-Zur Denise M. Tieman S. Jean Marlow Avtar K. Handa 《Plant molecular biology》1995,29(6):1101-1110
The effects of extended heat stress on polygalacturonase (PG; EC 3.2.1.15) and pectin methylesterase (PME; EC 3.1.1.11) gene expression at mRNA, protein and activity levels in ripening tomato fruits were investigated. Steady state levels of PG mRNA declined at temperatures of 27°C and above, and a marked reduction in PG protein and activity was observed at temperatures of 32°C and above. Exogenous ethylene treatment did not reverse heat stress-induced inhibition of PG gene expression. Transfer of heat-stressed fruits to 20°C partly restored PG mRNA accumulation, but the rate of PG mRNA accumulation declined exponentially with duration of heat stress. Heat stress-induced inhibition of PME mRNA accumulation was recoverable even after 14 days of heat stress. In fruits held at 34°C, both PG and PME protein and activity continued to accumulate for about 4 days, but thereafter PG protein and activity declined while little change was observed in PME protein and activity. In spite of increases in mRNA levels of both PG and PME during the recovery of heat-stressed fruit at 20°C, levels of PG protein and activity declined in fruits heat-stressed for four or more days while PME protein and activity levels remained unchanged. Collectively, these data suggest that PG gene expression is being gradually and irreversibly shut off during heat stress, while PME gene expression is much less sensitive to heat stress. 相似文献
17.
Oxygen consumption and flight muscle activity during heating in workers and drones of Apis mellifera
Franz Goller Harald E. Esch 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1991,161(1):61-67
Summary Instantaneous oxygen consumption, muscle potential frequency, thoracic and ambient temperature were simultaneously measured during heating in individual workers and drones of honey bees. Relationships between these parameters and effects of thoracic temperature on power input and temperature elevation were studied. Oxygen consumption increased above basal levels only when flight muscles became active. Increasing muscle potential frequencies correlated with elevated oxygen consumption and raised thoracic temperature. The difference between thoracic and ambient temperature and oxygen consumption were linearly related. Oxygen consumption per muscle potential (l O2 · g
–1
thorax
· MP–1) was two-fold higher in drones than in workers. However, oxygen consumption for heating the thorax (l O2 · g
–1
thorax
· (Tth-Ta) · °C–1) was nearly the same in workers and drones. Thoracic temperature affected the amount of oxygen consumed per muscle potential (R10=1.5). Achieved temperature elevation per 100 MP was more temperature sensitive in drones (R10=6–10) than in workers (R10=3.6). Q10 values for oxygen consumption were 3 in workers and 4.5–6 in drones. Muscle potential frequency decreased with a Q10=1.8 in workers and 2.7 in drones. Heating behaviour of workers and drones was different. Drones generated heat less continuously than workers, and showed greater interindividual variability in predilection to heat. However, the maximal difference between ambient and thoracic temperature observed was 22 °C in drones and 14 °C in workers, indicating greater potential for drones.Abbreviations
DL
dorsal-longitudinal muscle
-
DV
dorsoventral muscle
-
MP
muscle potential
-
T
a
ambient temperature
-
T
th
thoracic temperature 相似文献
18.
S. Reuveny Y. J. Kim C. W. Kemp J. Shiloach 《Applied microbiology and biotechnology》1993,38(5):619-623
The effect of temperature and O2 saturation on the production of recombinant proteins -galactosidase and human glucocerebrosidase by Spodoptera frugiperda cells (Sf9) infected with recombinant Autographa californica nuclear polyhedrosis virus was investigated. The rates of cell growth, glucose consumption, O2 consumption and product expression were measured at temperatures between 22° C and 35° C. The results indicated that possible O2 limitation may be alleviated without compromising the maximum cell yield by lowering the incubation temperature from 27° C to 25° C. The expression level of the recombinant proteins at 27° C was similar to that obtained at 22° C and 25° C; lower protein yields were obtained at 30° C. An increase in temperature from 22° C to 27° C led to earlier production of the proteins and to an increase in the proportion of the product released outside the cells.
Correspondence to: J. Shiloach 相似文献
19.
A protocol for storage of emu semen >6 h has not yet been optimized. The objective was to determine: a) whether sperm quality was adversely affected by sudden exposure to low temperatures (5, 10 and 20 °C) during collection; and b) the effects of three storage temperatures (5, 10 and 20 °C) on survival of emu sperm. In two experiments, each repeated three times on alternate days, ejaculates were diluted 1:1 with precooled (5, 10, or 20°C) UWA-E3 diluent and stored for up to 48 h. Collection temperature, or interaction with either the storage time or storage temperature, had no significant effect on sperm viability, motility, or morphology. Mass Motility Score (2.91-3.27 ± 0.26, mean ± SEM), and percentages of live (72.4-76.2 ± 2.4) and morphologically normal sperm (63.3-64.5 ± 2.3) were comparable among collection temperatures. Conversely, storage temperature and storage time affected (P < 0.05) sperm viability, motility, and morphology. After storage for 48 h, percentages of viable, normal, and motile sperm were higher (P < 0.001) at 5 °C (58.7% ± 1.1, 44.7% ± 1.3, and 50.7% ± 4.9, respectively) and 10 °C (62.6% ± 1.1, 54.1% ± 1.3, and 60.4% ± 4.9) than at 20 °C (27.6% ± 1.1, 20.1% ± 1.3, and 25.9% ± 4.9). Beyond 6 h of storage, the percentage of abnormal sperm was higher (P < 0.001) for storage at 5 °C compared to 10 and 20 °C. After 48 h, bacterial counts were considerably higher at 20 °C compared to 5 and 10 °C (P < 0.001). The pH of stored sperm suspension remained unaffected at 5 and 10 °C, but at 20 °C declined to 6.5 ± 0.03 after 24 h (P < 0.05) and to 6.0 ± 0.03 after 48 h (P < 0.001). We concluded that emu semen could be collected at low ambient temperatures (5-20 °C) without compromising its in vitro storage duration and that semen quality during storage for 48 h was better if it was stored at 10 °C than at 5 or 20 °C. 相似文献
20.
Females of Zeiraphera canadensis Mut. & Free., the spruce bud moth, were reared in the laboratory at constant and alternating temperatures, and in an outdoor insectary, to (1) determine the effects of temperature, age and size on several reproductive parameters and, (2) to test the hypothesis that body size-temperature interactions influence longevity and realized fecundity. Egg maturation was linearly related to age and large moths developed eggs at a higher rate than small ones. Mcan lifetime oviposition rate reached a maximum and remained stable at temperatures 20° C while the mean lifetime rate of egg maturation increased linearly with temperature, indicating that higher temperatures adversely affect oviposition. The production of nonviable eggs increased with age but also with temperature, suggesting high temperature (25° C) reduces egg quality and/or hinders fertilization. The realized fecundity and longevity of females reared under an alternating temperature regime (mean 20° C) was significantly less than that of females reared at constant 20° C. Similar realized fecundity, longevity and mean lifetime oviposition rates for females reared at temperatures alternating between 10 and 25° C (mean 20° C) and those at constant 25° C reflected the inability of females to recover from elevated diurnal temperatures. Longevity was positively related to female body size at constant 15 and 20° C but the relationships were negative for moths exposed to diurnal temperatures equal to or exceeding 25° C. Due to the reduced longevity of large moths at high temperatures, linear regressions between size and realized fecundity were only significant at constant temperatures 20° C. At higher temperatures, the size-fecundity relationship became curvilinear as a result of the diminished reproductive output of large individuals. Reduced fecundity and longevity of large females at high temperatures may have been due to elevated internal temperatures of large-bodied moths. Large females in a controlled-environment chamber maintained at 25° C developed an internal temperature excess (i.e. temperature above ambient) of nearly 2° C while small-bodied females exceeded ambient by only 0.3° C. However, when held at 20° C, the temperature excess of large-bodied moths was much less than 1° C and small-bodied females did not differ from ambient. Such interactions between temperature and body size suggest that there should be stabilizing selection toward moderate-sized individuals and may explain the absence of size-related effects on fecundity and longevity previously reported for several other lepidopterans. 相似文献