Respiration,ATP level,and sugar accumulation in potato tubers during storage at 4°

A kinetic study was made of the relationship between respiration rate, sugar content and ATP levels, in fresh and aged potato tubers stored at 4°. The ATP content in tubers rose rapidly immediately after the chilling stress, while respiration rate decreased below the initial rate and sugar accumulation was not detected. After 4 days of storage, the ATP level declined and the sugars started to accumulate. The typical increase in respiration rate that usually follows chilling stress, appeared only in fresh tubers (at about the 6th day of storage). In dinitrophenol-treated tubers, the ATP level remained below the initial level and sugar accumulation was blocked completely. The evidence presented suggests that ATP elevation is not generated by the respiration burst.     

Possible apical respiration in the olfactory epithelium of the frog Rana temporaria

Bioluminescent analysis has been made of the effect of oxygen supply on the content of ATP in the isolated olfactory epithelium of the frog. It was shown that storage of epithelium preparations in the air increases their ATP content. When preparations are kept in the atmosphere of an inert gas, ATP level in the epithelium rapidly decreases, being recovered after transition of preparations to the air medium. The data obtained indicate the existence of apical type of respiration in the olfactory epithelium of the frog.     

Defective intramitochondrial NADH oxidation in skin fibroblasts from an infant with fatal neonatal lacticacidemia.

A small-for-gestational-age female infant born at term developed severe lactic acidosis and died on day 13 of life. Two previous sibs had also died of overwhelming lactic acidosis in the neonatal period. The lactate-to-pyruvate and 3-hydroxybutyrate-to-acetoacetate ratios were elevated at 136 and 42 to one, respectively. The activities of the pyruvate dehydrogenase complex and pyruvate carboxylase in cultured skin fibroblasts were normal but a defect in respiration was indicated by the low rates of conversion of 1-[14C]pyruvate, glutamate, and lactate to 14CO2 in these cells. Skin fibroblast cultures also displayed an elevated lactate-to-pyruvate ratio (72:1) when incubated with glucose as substrate compared to control cell cultures (20:1). When mitochondrial preparations of skin fibroblasts (prepared by digitonin extraction) were tested for their ability to synthesize ATP from a variety of substrates, it was found that those of the patient made adequate amounts of ATP with either succinate or ascorbate/tetramethyl-phenylenediamine as substrate but not with the NAD-linked substrates pyruvate, isocitrate, and palmitoyl carnitine. We propose that this is indicative of a defect in the respiratory chain between NADH and coenzyme Q, for the first time demonstrable in cultured skin fibroblasts.     

Changes in Adenosine Pyrophosphates in Cantaloupe Fruit Ripening Normally and after Treatment with Ethylene

During the climacteric rise in respiration of cantaloupe fruit(Cucumis melo L., var. reticulatus Naud.) the concentrationper gramme fresh weight of adenosine triphosphate (ATP) increasedand that of adenosine diphosphate (ADP) did not change; thusa net synthesis of adenosine pyrophosphate occurs during therespiratory climacteric. A net synthesis of protein which wasobserved was positively correlated with the concentration ofATP. Ethylene treatment stimulated a climacteric-like rise inthe respiration and in the rate of ripening in fruit harvestedat 9 to 32 days after anthesis. The ratio ATP/ADP increasedin fruit ripened with ethylene only when harvested 20 days ormore after anthesis.     

Nitrogenase activity and regeneration of the cellular ATP pool in Azotobacter vinelandii adapted to different oxygen concentrations.

The in vivo activity of nitrogenase under aerobiosis was studied with diazotrophic chemostat cultures of Azotobacter vinelandii grown under glucose- or phosphate-limited conditions at different dilution rates (Ds, representing the growth rate mu) and different dissolved oxygen concentrations. Under steady-state conditions, the concentration as well as the cellular level of ATP increased in glucose-limited cultures when D was increased. Irrespective of the type of growth limitation or the dissolved oxygen concentration, the steady-state concentrations of ATP and of dinitrogen fixed by nitrogenase increased in direct proportion to each other. Specific rates of dinitrogen fixation as well as of the regeneration of the cellular ATP pool were compared with specific rates of cellular respiration. With glucose-limited cultures, the rate of regeneration of the ATP pool and the rate of respiration varied in direct proportion to each other. This relationship, however, was dependent on the dissolved oxygen concentration. As compared to the phosphate-sufficient control, phosphate-limited cultures exhibited the same nitrogenase activity but significantly increased respiratory activities. Rates of ATP regeneration and of cellular respiration of phosphate-limited cultures did not fit into the relationship characteristic of glucose-limited cultures. However, a linear relationship between the rates of dinitrogen fixation and ATP regeneration was identified irrespective of the type of growth limitation and the dissolved oxygen concentration. The results suggest that the ATP supply rather than cellular oxygen consumption is of primary importance in keeping nitrogenase activity in aerobic cultures of A. vinelandii.     

Control of respiration and metabolism in growing Klebsiella aerogenes. The role of adenine nucleotides

1. A rapid-sampling technique was used to obtain perchloric acid extracts of cells growing in a chemostat culture, so that meaningful values for ATP content could be obtained in spite of the fact that the turnover time for the total ATP content was about 1sec. 2. For steady-state growth, it was found that, in a glucose-limited chemostat culture, the ATP/ADP concentration ratio was approximately constant with changes in dissolved-oxygen tensions above the critical value, but fell when the culture was grown under oxygen-limited conditions and was at a minimum in anaerobically grown cultures. The steady-state ATP content was lower in cells growing under nitrogen-limited conditions with glucose in excess than in glucose-limited cells. The steady-state ATP content was independent of growth rate at growth rates over 0.1hr.(-1). 3. When the respiration rate of the cells was stimulated by lowering the oxygen tension the ATP content did not increase, indicating either an increased turnover rate of ATP or a fall in the P/O ratio. The sudden addition of extra glucose or succinate to a glucose-limited culture increased the respiration rate of the cells, but the ATP content quickly returned to the steady-state value after initial perturbations. This control over ATP content is explained in terms of regulation by adenine nucleotides of the catabolism and anabolism of glucose. An exception to this control over ATP content was found when the respiration rate was stimulated by addition of an antifoam.     

Are growth rates of Escherichia coli in batch cultures limited by respiration?

Batch cultures of Escherichia coli were grown in minimal media supplemented with various carbon sources which supported growth at specific growth rates from 0.2 to 1.3/h. The respiration rates of the cultures were measured continuously. With few exceptions, the specific rate of oxygen consumption was about 20 mmol of O2/h per g (dry weight), suggesting that the respiratory capacity was limited at this value. The adenosine triphosphate (ATP) required for the production of cell material from the different carbon sources was calculated on the basis of known ATP requirements in the biochemical pathways and routes of macromolecular synthesis. The calculated ATP requirements, together with the measured growth rates and growth yields on the different carbon sources, were used to calculate the rate of ATP synthesis by oxidative phosphorylation. This rate was closely related to the respiration rate. We suggest that aerobic growth of E. coli in batch cultures is limited by the rate of respiration and the concomitant rate of ATP generation through oxidative phosphorylation.     

Use of cryopreserved peripheral mononuclear blood cells in biomonitoring

This study was performed to investigate the effect of storing blood samples by freezing on selected biomarkers and possible implications for biomonitoring. Comparative measurements were performed in order to investigate the use of cryopreserved vs. freshly separated peripheral mononuclear blood cells (PMBC) obtained from donor blood. Measurements of DNA-repair, mutant frequency, and subcell content were included. Samples for large biomonitoring studies are usually taken from study groups within a short timeperiod of days/weeks and storing of study material for later analysis can be necessary. We measured the DNA repair activity as dimethylsulfate induced unscheduled DNA synthesis (UDS) in PMBC incubated with either autologous plasma or fetal bovine serum (FBS). Comparison of the hprt mutant frequency by the T cell cloning assay was made in parallel. Finally the content of B/T-lymphocytes and monocytes was measured in phytohemaglutinin (PHA)-stimulated cultures at different time intervals. The results showed a higher DNA repair activity in cryopreserved samples compared with fresh samples. We also found differences in mutant frequencies with higher values in fresh samples. A significant correlation of frequencies was seen when comparing fresh with cryopreserved samples. Furthermore we recommend fresh human plasma used in UDS incubation media.     

Use of cryopreserved peripheral mononuclear blood cells in biomonitoring

This study was performed to investigate the effect of storing blood samples by freezing on selected biomarkers and possible implications for biomonitoring. Comparative measurements were performed in order to investigate the use of cryopreserved vs. freshly separated peripheral mononuclear blood cells (PMBC) obtained from donor blood. Measurements of DNA-repair, mutant frequency, and subcell content were included. Samples for large biomonitoring studies are usually taken from study groups within a short time period of days/weeks and storing of study material for later analysis can be necessary. We measured the DNA repair activity as dimethylsulfate induced unscheduled DNA synthesis (UDS) in PMBC incubated with either autologous plasma or fetal bovine serum (FBS). Comparison of the hprt mutant frequency by the T cell cloning assay was made in parallel. Finally the content of B/T-lymphocytes and monocytes was measured in phytohemaglutinin (PHA)-stimulated cultures at different time intervals. The results showed a higher DNA repair activity in cryopreserved samples compared with fresh samples. We also found differences in mutant frequencies with higher values in fresh samples. A significant correlation of frequencies was seen when comparing fresh with cryopreserved samples. Furthermore we recommend fresh human plasma used in UDS incubation media.     

Preparation and characterization of myosin from cultured cells of Escherichia coli (02:K1 30156 strain)

In this study the myosin preparations isolated from E. Coli cell cultures were analysed. The isolation of myosin from fresh cultures resulted in a substantially higher (approximately 10-fold) yield than from stored cells. The coli myosin, despite the two DEAE-cellulose treatments, contained more RNA and P-lipid than the myosin prepared from skeletal muscle. The RNA content can be removed gradually by acetone denaturation and lipid removal followed by subsequent washings. The fresh preparations contained protein-bound alkali-stable P; part of this was released by Cu ions. The coli myosin can be phosphorylated. The phosphate uptake depended on the concentrations of ATP and Mg2+ and on the time of incubation. The alkaline hydrolysate of the phosphorylated, washed lipid-free preparation was resolved into 8 P-containing peaks on ion-exchange chromatography. Of fractions P-Arg, Pi, P-Lys and 2 P-His conformer were identified by means of synthetic compounds, elution pattern and specific reactions. The remaining compounds could not be identified. The most abundant component was P-Arg suggesting that this compound might play an important role in the cytokinetic movements of E. coli.     

Effects of Cyanide and Ethylene on the Respiration of Cyanide-sensitive and Cyanide-resistant Plant Tissues

The effects of cyanide and ethylene, respectively, were studied on the respiration of a fully cyanide-sensitive tissue-the fresh pea, a slightly cyanide-sensitive tissue-the germinating pea seedling, and a cyanide-insensitive tissue-the cherimoya fruit. Cyanide inhibition of both fresh pea and pea seedling respiration was attended by a conventional Pasteur effect where fermentation was enhanced with an accumulation of lactate and ethanol and a change in the level of glycolytic intermediates indicative of the activation of phosphofructokinase and pyruvate kinase accompanied by a sharp decline in ATP level. In these tissues, ethylene had little or no effect on the respiration rate, or on the level of glycolytic intermediates or ATP. By contrast, ethylene as well as cyanide enhanced both respiration and aerobic glycolysis in cherimoya fruits with no buildup of lactate and ethanol and with an increase in the level of ATP. The data support the proposition that for ethylene to stimulate respiration the capacity for cyanide-resistant respiration must be present.     

SHORT-TERM RESPONSES OF NUTRIENT-DEFICIENT ALGAE TO NUTRIENT ADDITION1

Changes in net photosynthesis, dark respiration, ATP content, and some other aspects of composition were measured following phosphate or ammonium addition to cultures of the green alga Scenedesmus quadricauda (Turp.) Bréb. deficient in phosphorus or nitrogen. The deficient nutrient was rapidly taken up. Light-saturated net photosynthesis was depressed below the pre-addition rate during nutrient uptake and did not increase markedly above that rate until several hours after uptake was complete. Dark respiration, on the other hand, was markedly stimulated during uptake of the deficient nutrient and to a lesser extent after uptake was complete. Phosphate addition to P-deficient cells caused a large increase in the ATP content within 2–4 h of addition, whereas ammonium addition to N-deficient cells caused much less or no increase in ATP content. Short-term enrichment experiments to detect nutrient limitations are evaluated in the light of these and similar results taken from the literature. The available evidence shows that photosynthetic responses cannot reliably be used in short-term enrichments but changes in respiration or ATP content may be useful in certain circumstances.     

Starvation-Survival Physiological Studies of a Marine Pseudomonas sp

Starved cultures of a marine Pseudomonas sp. showed a 99.9% decrease in viable cell count during the first 25 days of starvation, yet the culture maintained 10 viable cells per ml for over 1 year. The physiological responses of populations of a marine Pseudomonas sp. to nutrient starvation were observed for periods of up to 40 days. At various intervals during starvation, the numbers of total, viable, and respiring cells were determined within the cultures. The ATP content, endogenous respiration rate, uptake rates, and percent respiration for exogenous glucose and glutamate were determined throughout the starvation period to characterize the physiological changes in the cells. It was observed that, after initial adjustment periods, all parameters tested reached stabilized states after 18 to 25 days of starvation. The results indicate that the actively respiring subpopulation, rather than the viable or total cell numbers, is the most appropriate denominator for interpretation of observed activities on an individual cell basis.     

The relation of sodium and potassium ion transport to the respiration and adenine nucleotide content of liver slices treated with inhibitors of respiration

1. The dependence of the net transport of Na(+) and K(+) by rat liver on the respiration has been determined by incubating slices in the presence of varying concentrations of respiratory inhibitors. 2. Neither the rate of net transport nor the total amount of each ion transported was inhibited unless the rate of endogenous respiration was decreased below a critical value of about 330mmol of O(2)/h per kg of protein (i.e. 50% of the total endogenous respiration). 3. The uninhibited rate of respiration could be varied over a twofold range (380-770mmol of O(2)/h per kg of protein) by the use of different substrates, but the critical value for the onset of transport inhibition was quite constant (290-360mmol/h per kg of protein) under these different conditions. 4. Slices incubated at 38 degrees C without inhibitors showed an increase of their ATP content and the concentration ratio ATP/ADP. The final ATP content and concentration ratio, ATP/ADP, of slices treated with different concentrations of inhibitors were closely related to the rate of respiration. 5. The increased ATP content of the control slices during incubation was equal to the increase of total adenine nucleotides. At increasing degrees of respiratory inhibition the relative contributions of ADP and AMP to the total adenine nucleotide content increased. 6. The critical rate of respiration for the onset of inhibition of ion transport and the corresponding contents of adenine nucleotides provide estimates of the maximal values of certain parameters of energy metabolism required for the support of alkali-cation transport in the liver slices.     

The influence of phosphate deficiency on photosynthesis, respiration and adenine nucleotide pool in bean leaves

The decrease in inorganic phosphate (Pi) content of 10-d-old Phaseolus vulgaris L. plants did not affect rates of photosynthesis (PN) and respiration (RD), leaf growth, and adenylate concentration. Two weeks of phosphate starvation influenced the ATP content and leaf growth more than PN and RD. The ATP concentration in the leaves of 15- and 18-d-old phosphate deficient (-P) plants after a light or dark period was at least half of that in phosphate sufficient (+P, control) plants. Similar differences were found in fresh and dry matter of leaves. However, PN declined to 50 % of control in 18-d-old plants only. Though the RD of -P plants (determined as both CO2 evolution and O2 uptake) did not change, an increased resistance of respiration to KCN and higher inhibition by SHAM (salicylhydroxamic acid) suggested a higher engagement of alternative pathway in respiration and a lower ATP production. The lower demand for ATP connected with inhibition of leaf growth may influence the ATP producing processes and ATP concentration. Thus, the ATP concentration in the leaves depends stronger on Pi content than on PN and RD.     

Regulation of respiration in rotenone-treated tobacco cell suspension cultures

Cells of Nicotiana tabacum L. suspension cultures were treated with the respiratory inhibitor rotenone, which specifically inhibits complex I activity of mitochondria. Rotenone retarded cell growth, as shown by decreases in fresh weight, dry weight and cell numbers on a suspension-volume basis. However, rates of the coupled respiration were higher in rotenone-treated compared to control cells when expressed on a fresh-weight basis. Rates of the rotenone-insensitive respiration increased substantially on both a fresh-weight and extractable-cellular-protein basis 24 h after rotenone treatment. ATP/ADP ratios were not significantly different between control and rotenone-treated cells. Our results indicated that cells of tobacco suspension cultures were able to maintain a slow rate of growth and adequate ATP/ADP ratios without the operation of complex I. Received: 12 June 2000 / Accepted: 2 August 2000     

华北平原地区麦田土壤呼吸特征

2008年4-6月利用LI-8100及LI-6400-09测定了华北平原典型冬小麦田土壤CO_2通量,并分析了麦田土壤呼吸变化规律及其影响机制.结果表明:土壤呼吸日变化呈明显的单峰曲线,最高值出现在12:30-14:30,最低值出现在5:00-6:30;在不同的天气条件下,土壤呼吸速率晴天最高,多云其次,阴天最小;观测期间冠层内各高度CO_2浓度与麦田土壤呼吸速率白天呈显著线性负相关,夜间正相关;土壤呼吸速率与5 cm地温的季节变化趋势基本一致,二者显著指数相关;在田间持水量范围内,土壤呼吸速率与土壤湿度正相关,当土壤相对湿度低于30%时,土壤呼吸受到抑制而通量降低;综合考虑土壤温度与湿度的双因素指数回归模型能较好地解释土壤呼吸的变化情况,土壤温度低于15 ℃时效果更好.

Abstract：

By using LI-8100 and LI-6400-09, the soil CO_2 flux of a winter wheat field in North China Plain was determined from April to June 2008, with its change patterns and affecting fac-tors analyzed. The soil respiration had a single-peak diurnal variation, with the maximum at 12: 30-14:30 and the minimum at 5:00-6:30, and the respiration rate was higher in sunny days than in cloudy or overcast days. There was a significant negative correlation between the CO_2 con-centrations at all canopy heights and the soil respiration rate at daytime, but a significant positive correlation at night. The soil respiration rate presented a seasonal variation similar to the soil tem-perature at 5 cm depth, and had a significant exponential relationship with the soil temperature. Significant correlation was also found between the soil respiration rate and soil humidity when the soil moisture content was within the range of field capacity. Soil humidity less than 30% would limit the soil respiration, inducing a decrease of soil CO_2 flux. A multiple exponential regression model of soil temperature and moisture could better explain the variation of soil respiration, espe-cially when the soil temperature was below 15 ℃.     

Vitrification of carnation in vitro: Changes in ethylene production,ACC level and capacity to convert ACC to ethylene

Carnation tissue was allowed to vitrify in liquid culture and ethylene production, ACC content and capacity to convert ACC to ethylene were measured in comparison to tissue developing normally on solid medium. Flask atmospheres of liquid cultures accumulated ethylene at a higher rate during the first four days. Daily ethylene production by vitrifying material decreased later. Ethylene emission by vitrifying tissues always remained above controls when subcultured daily to fresh medium. Explants and microsomal preparations from vitrifying carnations converted ACC to ethylene at a higher degree from the first day in liquid medium. ACC level markedly increased in vitrifying tissues during the first two days of liquid culture. Raising the level of ethylene in the atmosphere of solid cultures did not induce vitrification symptoms nor did use of inhibitors of ethylene biosynthesis in liquid cultures prevent the process. The role of ethylene in vitrification is reappraised.     

Time course of osmotic adaptation and gill energetics of rainbow trout (Salmo gairdneri R.) following abrupt changes in external salinity

Summary The physiological and biochemical responses of rainbow trout (mean weight 250 g) to abrupt increases in salinity have been investigated. An initial crisis period lasting about 30 h was characterized by an increase in plasma and muscle ions, a rapid gill dehydration and a pronounced acidosis following a transient alkalosis. Mortality was low during this period. During the following days, gradual changes resulted in new steady state levels for most parameters examined.Analysis of adenylate pool (ATP, ATP/ADP ratio and energy charge) in the gills demonstrated an increased energy demand exhibiting two phases (4 h and 3 days), and a return to freshwater values. The gill respiration rate was constant during 3 days in sea water and decreased slightly later on. It was not influenced during the reverse transfer of seawater adapted fish into fresh water at the level of either isolated gills or perfused heads.     

Changes of Respiration Rate, Ethylene Evolution, and Abscisic Acid Content in Developing Inflorescence and Young Fruit of Olive (Olea europaea L. cv. Konservolia)

Simultaneous measurements of respiration, ethylene production, and abscisic acid (ABA) concentrations, as well as the growth parameters length, fresh weight (FW), and dry weight (DW) of olive (Olea europaea L. cv. Konservolia) inflorescence were carried out at short intervals (3–7 days) during the period from bud burst until the 3rd week after full bloom (AFB), when young fruit reached 8 mm in length. The axis of inflorescence elongated remarkably during the 3rd week after bud burst (ABB), massive bract shedding occurred during the 4th week ABB, full bloom (FB) was observed 7 weeks ABB, and massive floral organ abscission 1 week AFB. The results showed a continuous increase in inflorescence FW and DW from bud burst until 4 days before FB. Respiration rate, ethylene production, and levels of ABA were relatively high during the first 3 weeks ABB. After this period, respiration and ethylene followed a similar pattern of changes, inversely to that of ABA concentration. An accumulation of inflorescence ABA 6 and 4 days before FB was associated with the minimum values of respiration and ethylene production on the same dates. The sharp decrease in the ABA concentration during FB and 3 days later was followed by a high rise in ethylene and an increase in respiration rate, which both rose further 1 week AFB. The results suggest a possible correlation of ABA with the early stage of floral abscission, whereas ethylene production seems to be correlated with the terminal separatory activity in olive inflorescence abscission processes. Received May 28, 1998; accepted November 17, 1998