Comparison of temperature effects on soil respiration and bacterial and fungal growth rates

Temperature is an important factor regulating microbial activity and shaping the soil microbial community. Little is known, however, on how temperature affects the most important groups of the soil microorganisms, the bacteria and the fungi, in situ. We have therefore measured the instantaneous total activity (respiration rate), bacterial activity (growth rate as thymidine incorporation rate) and fungal activity (growth rate as acetate-in-ergosterol incorporation rate) in soil at different temperatures (0-45 degrees C). Two soils were compared: one was an agricultural soil low in organic matter and with high pH, and the other was a forest humus soil with high organic matter content and low pH. Fungal and bacterial growth rates had optimum temperatures around 25-30 degrees C, while at higher temperatures lower values were found. This decrease was more drastic for fungi than for bacteria, resulting in an increase in the ratio of bacterial to fungal growth rate at higher temperatures. A tendency towards the opposite effect was observed at low temperatures, indicating that fungi were more adapted to low-temperature conditions than bacteria. The temperature dependence of all three activities was well modelled by the square root (Ratkowsky) model below the optimum temperature for fungal and bacterial growth. The respiration rate increased over almost the whole temperature range, showing the highest value at around 45 degrees C. Thus, at temperatures above 30 degrees C there was an uncoupling between the instantaneous respiration rate and bacterial and fungal activity. At these high temperatures, the respiration rate closely followed the Arrhenius temperature relationship.     

Desulfobacter psychrotolerans sp. nov., a new psychrotolerant sulfate-reducing bacterium and descriptions of its physiological response to temperature changes

A psychrotrolerant acetate-oxidizing sulfate-reducing bacterium (strain akvb(T)) was isolated from sediment from the northern part of The North Sea with annual temperature fluctuations between 8 and 14 degrees C. Of the various substrates tested, strain akvb(T) grew exclusively by the oxidation of acetate coupled to the reduction of sulfate. The cells were motile, thick rods with round ends and grew in dense aggregates. Strain akvb(T) grew at temperatures ranging from -3.6 to 26.3 degrees C. Optimal growth was observed at 20 degrees C. The highest cell specific sulfate reduction rate of 6.2 fmol cell(-1) d(-1) determined by the (35)SO(2-)(40) method was measured at 26 degrees C. The temperature range of short-term sulfate reduction rates exceeded the temperature range of growth by 5 degrees C. The Arrhenius relationship for the temperature dependence of growth and sulfate reduction was linear, with two distinct slopes below the optimum temperatures of both processes. The critical temperature was 6.4 degrees C. The highest growth yield (4.3-4.5 g dry weight mol(-1) acetate) was determined at temperatures between 5 and 15 degrees C. The cellular fatty acid composition was determined with cultures grown at 4 and 20 degrees C, respectively. The relative proportion of cellular unsaturated fatty acids (e.g. 16:1omega7c) was higher in cells grown at 4 degrees C than in cells grown at 20 degrees C. The physiological responses to temperature changes showed that strain akvb(T) was well adapted to the temperature regime of the environment from which it was isolated. Phylogenetic analysis showed that strain akvb(T) is closest related to Desulfobacter hydrogenophilus, with a 16S rRNA gene sequence similarity of 98.6%. DNA-DNA-hybridization showed a similarity of 32% between D. hydrogenophilus and strain akvb(T). Based on phenotypic and DNA-based characteristics we propose that strain akvb(T) is a member of a new species, Desulfobacter psychrotolerans sp. nov.     

分子伴侣grp75在缺糖损伤细胞恢复中的作用

葡萄糖调节蛋白75(grp75)属于热休克蛋白70家族中的一员,细胞中葡萄糖水平下降时(类似于缺血),grp75表达增高。为研究grp75在缺糖及缺糖再灌注条件下对细胞的作用,本文以中国仓鼠肺细胞株CHL为材料,采用脂质体介导的方法,以grp75表达载体pcDNA3/grp75转染CHL细胞,获得过表达grp75的细胞克隆;置于无糖培养基培养20h及无糖培养12h换含糖培养基继续培养8h(缺糖再灌注)或含糖培养20h,运用MTT法、LDH测定和流式细胞术分析等方法评估细胞损伤程度。MTT测定显示,未转染细胞缺糖再灌流的增殖能力比完全培养20h增殖能力明显降低(p<0.05),且低于无糖培养20h(p<0.05),转染细胞缺糖再灌流的增殖能力明显高于对照组(p<0.01);LDH测定结果显示,未转染细胞缺糖再灌流LDH释放百分比显著高于完全培养20h(p<0.01),与无糖培养20h无明显差别(p>0.05),转染细胞缺糖再灌流LDH释放百分比显著低于对照组(p<0.01);流式细胞术分析表明,转染细胞的凋亡率明显低于对照组。以上结果表明grp75过表达的细胞在缺糖损伤细胞的恢复中具有一定强度的抗损害作用。     

分子伴侣grp75在缺糖损伤细胞恢复中的作用

Glucose-regulated proteins 75(grp75) is a member of hsp70 family. The expression of grp75 is upregulated during glucose starvation (such as ischemia). To evaluate grp75 function, CHL cells were cultured with glucose-free media for 20 h (A) and glucose-free media for 12 h + glucose-containing media for 8 h (ischemia reperfusion) (B). A constructed rat grp75 cDNA expression vector (pcDNA/grp75) was transfected into CHL cells and a cell strain that stably overexpressed grp75 was obtained. The transfected cells and untransfected cells(control group) were cultured with A or B. By MTT, LDH leakage measurement and flow cytometry analysis, growth rate of untransfected cells in B is significantly lower than that in glucose-containing media for 20 h (C) (p < 0.05) and A (p < 0.05). Growth rate of transfected cells is apparently higher than that of control group in B (p < 0.01). LDH liberation percentage of untransfected cells in B is obviously higher than that in C(p < 0.01) and it is not different from A(p > 0.05). LDH liberation percentage of transfected cells is apparently lower than that of control group in B(p < 0.01). Apoptosis of transfected cells is obviously lower by flow cytometry analysis. These results provide evidence for the cytoprotective function of grp75 during glucose starving and ischemia reperfusion.     

Comparison of biooxidation with carbon dioxide assimilation during bacterial growth on ferrous ion or elemental sulfur.

Biomass and oxygen uptake activity profiles of a mixed bioleaching culture were studied and compared at various temperatures. Bacteria were grown on ferrous ion or elemental sulfur in a Micro-Oxymax respirometer apparatus that allowed measurement of both oxygen consumption and carbon dioxide assimilation. Balanced growth was observed between 10 degrees C and 35 degrees C, with an optimum at 30 degrees C, on both energy sources. No significant growth was observed at the lowest temperature used, 5 degrees C, or at the highest temperature used, 40 degrees C. The oxygen to carbon dioxide molar yield was 50:1 when growing on ferrous ion but only 17:1 when growing on elemental sulfur. Upon transfer from a sulfide ore to a new energy source, greater numbers in the inoculum reduced the duration of the lag phase. Lag phase duration was also reduced by proximity to the optimum growth temperature. A longer lag phase decreased the achievable growth rate of the cells exponentially, significantly affecting biooxidation activity.     

Relationship between the heat resistance of spores and the optimum and maximum growth temperatures of Bacillus species

Heat resistance of spores of Bacillus strains was compared with the temperature adaptation of each strain as measured by the optimum and maximum growth temperatures and the heat resistance of vegetative cells. Maximum growth temperatures ranged from 31 to 76 degrees C and were little affected by the nature of the growth medium. The temperature giving maximum growth rate was closely correlated to the maximum temperature for growth, and about 6 degrees C lower. Vetetative-cell heat resistance, determined on exponential-phase cells, was also correlated with maximum growth temperature. The temperature at which spores were inactivated with a decimal reduction time of 10 min was in the range of 75 to 121 degrees C. This temperature was 46 +/- 7 degrees C higher than the maximum growth temperature and correlated with it and the other cell parameters. Spore heat resistance can be considered to have two components, the temperature adaptation characteristic of the species and the stabilization conferred by the spore state.     

Effect of different cryoprotectants and transfer temperatures on the survival rate of hemp (Cannabis sativa L.) cell suspension in deep freezing

Adequate cell dehydration is the precipitating element in the successful cryopreservation of plant cells and organs. This could be achieved by using different cooling rates, transfer temperatures and cryoprotectants. Experiments were performed to determine these critical points in the freeze preservation procedure of Cannabis sativa (L.) suspension cultures. The explants were frozen at a cooling rate of 2 degrees C/min, while the transfer temperatures were -10 degrees C, -20 degrees C, -30 degrees C, -40 degrees C and -50 degrees C. The applied cryoprotectants were the DMSO, glycerol, proline and PEG in different concentration. The highest viability (58%) was obtained by using 10% DMSO and at -10 degrees C transfer temperature. The optimum transfer temperature varied remarkably by different cryoprotectant concentrations indicating the importance of their interactions.     

Extracellular factors of adaptation of Pneudomonas fluorescens batch cultures to adverse conditions

The culture liquid filtrate of an exponential-phase Pseudomonas fluorescens batch culture added to another P. fluorescens culture at the moment of inoculation was found (1) to prevent or diminish cell adsorption of the flask walls; (2) to enhance the intensity of cell respiration; (3) to shorten the period of adaptation of LB-grown cells to growth in glucose-containing mineral M9 medium; (4) to stimulate bacterial growth at supraoptimum temperature (36 degrees C) and pH values (4.8 and 9.2); and (5) to decrease the death rate of bacteria at the supraoptimum growth temperature. These results were interpreted as indicating that P. fluorescens cultures produce two types of regulatory exometabolites similar to those revealed earlier in Escherichia coli and Bacillus subtilis cultures: the direct-action adaptogenic factor XI capable of increasing bacterial resistance to unfavorable growth conditions (temperature and pH) and factor promoting adaptation to new media. Both factors are presumably low-molecular-weight hydrophilic nonprotein compounds.     

Effect of food processing-related stresses on acid tolerance of Listeria monocytogenes

Stationary-phase cells of Listeria monocytogenes grown in glucose-free or glucose-containing media were exposed for 90 min to various stresses, including acid stress (pH 4.0 to 7.0), osmotic stress (10.5 to 20.5% NaCl), and various temperatures (-5 to 50 degrees C), and were further exposed to pH 3.5. Exposure to a mildly acidic (pH 5.0 to 6.0) environment provided protection of the pathogen against acid upon subsequent exposure. This adaptive response, however, was found to be strongly dependent on other environmental conditions during the shock, such as temperature or the simultaneous presence of a second stress factor (NaCl). Growth of L. monocytogenes in the presence of glucose resulted in enhanced survival of the pathogen at pH 3.5. Sublethal stresses other than acidic stresses, i.e., osmotic, heat, and low-temperature stresses, did not affect the acid resistance of L. monocytogenes (P > 0.5). More-severe levels of these stresses, however, resulted in sensitization of the pathogen to acid.     

Carotenoid accumulation in the psychrotrophic bacterium Arthrobacter agilis in response to thermal and salt stress

A psychrotrophic strain of Arthrobacter agilis, isolated from Antarctic sea ice, grows from 5 degrees C to 40 degrees C and in culture media containing 0-10% (w/v) NaCl. Maximum growth rate occurred at 30-35 degrees C with a drastic decline as the cultivation temperatures diverged. Adaptation to extremes of low temperature may be partially attributed to the production of the C-50 carotenoid bacterioruberin, and its glycosylated derivatives. Lowering of the cultivation temperature resulted in a concomitant increase in carotenoid production, which may contribute to membrane stabilisation at low temperature. Maximum biomass accumulation occurred at 5-30 degrees C with a tenfold reduction at 40 degrees C. Changes in growth rates were minimal in culture media containing 0-2% (w/v) NaCl at 10 degrees C while a gradual decrease in growth rates occurred at higher salinity. Biomass accumulation at different salinity followed a trend similar to that observed with different cultivation temperatures. Maximum biomass accumulation was observed in culture media containing 0-5% (w/v) NaCl with a tenfold reduction at 10% (w/v) NaCl. Carotenoid production also decreased as salinity increased.     

Interactive effects of salt concentration and temperature on growth and lipid composition in the moderately halophilic bacterium Vibrio costicola.

The interactive effects of NaCl concentration and growth temperature on the growth and lipid composition of the moderately halophilic eubacterium Vibrio costicola have been investigated. Vibrio costicola was shown to be capable of growth over the temperature range 4-37 degrees C. Maximum growth yields were obtained at 30 degrees C when the optimum NaCl concentration was 1.0 M NaCl. In contrast with some previous studies, at higher or lower growth temperatures both the optimum and lower limit of NaCl concentration were higher, but there was no change in the upper limit of NaCl concentration for growth. There were no differences between the lipid compositions of cultures grown in 1 M NaCl at 30 or 37 degrees C, but as the growth temperature was lowered from 30 to 10 or 4 degrees C, the ratio of phosphatidylethanolamine to phosphatidylglycerol increased significantly as a result of the conversion of phosphatidylglycerol to diphosphatidylglycerol; in addition, at the lower growth temperatures the phospholipid fatty acyl composition became more unsaturated and the mean acyl chain length was shorter. It is suggested that the altered salt dependence of V. costicola at temperatures below the optimum for growth is due to a modification in membrane lipid phase behavior and stability brought about by changes in lipid composition, whereas a different mechanism operates above the growth temperature optimum.     

Factors influencing survival and growth of mammalian cells exposed to hypothermia. I. Effects of temperature and membrane lipid perturbers

The Arrhenius plot of the rate of V79 Chinese hamster cell inactivation due to hypothermia has a "break" around 7-10 degrees C with optimum storage temperature for unprotected cells being about 10 degrees C. Addition of the membrane lipid perturber, butylated hydroxytoluene, improves survival of cells when compared to controls at temperatures below this break but not above. Arrhenius plots of growth rates of the cells show breaks at 30 and 40 degrees C. Measurements of membrane fluidity by electron spin resonance or membrane polarization anisotropy by fluorescence spectrophotometry techniques as a function of temperature in these cells also reveal "breaks" centered around 8 and 30 degrees C. Hence, the changes in the rate of cell inactivation and growth as a function of temperature may be related to membrane lipid phase changes.     

Growth of Rhizobium japonicum Strains at Temperatures Above 27 degrees C

A study was conducted to examine the growth responses of different Rhizobium japonicum strains to increasing temperatures, determine the degree of variability among strains in those responses, and identify temperature-related growth characteristics that could be used to select temperature-tolerant strains. Each of 42 strains was grown in liquid culture for 96 h at 19 incubation temperatures ranging from 27.4 to 54.1 degrees C in a temperature gradient apparatus. Growth was estimated by measuring the change in optical density over time. Strains differed in their responses to increasing temperatures. Three characteristic temperatures were determined for each strain: the temperature giving the maximum optical density at 96 h (optimum temperature), the maximum temperature allowing a continuous increase in optical density during the 96-h period (maximum permissive temperature), and the maximum temperature allowing growth of the cultures after they were transferred to a uniform incubation temperature of 28 degrees C (maximum survival temperature). The three characteristic temperatures varied among strains and had the following ranges: optimum temperature, from 27.4 to 35.2 degrees C; maximum permissive temperature, from 29.8 to 38.0 degrees C; and maximum survival temperature, from 33.7 to 48.7 degrees C. Significant positive correlations were found between maximum permissive temperature and optimum temperature and between maximum permissive temperature and maximum survival temperature. Eight strains which had the highest maximum permissive temperature, optimum temperature, and maximum survival temperature were considered tolerant of high temperatures and were able to grow at temperatures higher than those previously reported for the most tolerant R. japonicum strains. The strains were of diverse geographical origin, but the response to high temperatures was not related to their origin. Evaluation of the temperature responses in pure culture may be useful in the search for R. japonicum strains better suited to environments in which high soil temperature is a limiting factor.     

Effects of temperature on the life history parameters and population growth rates of Hyalopterus pruni (Hemiptera: Aphididae)

The mealy plum aphid, Hyalopterus pruni (Geoffroy) (Hemiptera: Aphididae) is a pest of prune trees in California. The impact of aphids as pests is well characterized by their population growth rate, a parameter integrating their age-specific development, survivorship, and fecundity. These population parameters were measured at five constants temperatures on potted prune trees. Development rates increased with temperature up to an optimum. The relationship between development rate and temperature was described by linear and nonlinear models. Developmental threshold temperature was greater for the nonlinear model than for the linear model. Thermal requirement for development and maximum lethal temperature determined by these models were similar to those for other aphids. The greatest proportional survivorship of nymphs occurred at 26 degrees C. Mean daily fecundity was lowest at 14 degrees C and highest at 22 degrees C. Adult longevity decreased with temperature. Population growth rates for H. pruni were estimated from measurements of fecundity and development time and were highest at 22 degrees C. This is the first study to document the temperature dependence of the life history parameters for H. pruni and the first to generate a degree-day model for the prediction of phenological events.     

Effects of temperature on cell growth and xanthan production in batch cultures of Xanthomonas campestris

Batch xanthan fermentations by Xanthomonas campestris NRRL B-1459 at various temperatures ranging between 22 degrees C and 35 degrees C were studied. At 24 degrees C or lower, xanthan formation lagged significantly behind cell growth, resembling typical secondary metabolism. However, at 27 degrees C and higher, xanthan biosynthesis followed cell growth from the beginning of the exponential phase and continued into the stationary phase. Cell growth at 35 degrees C was very slow; the specific growth rate was near zero. The specific growth rate had a maximum value of 0.26 h(-1) at temperatures between 27 degrees C and 31 degrees C. Cell yield decreased from 0.53 g/g glucose at 22 degrees C to 0.28 g/g glucose at 33 degrees C, whereas xanthan yield increased from 54% at 22 degrees C to 90% at 33 degrees C. The specific xanthan formation rate also increased with increasing temperature. The pyruvate content of xanthan produced at various temperatures ranged between 1.9% and 4.5%, with the maximum occurring between 27 degrees C and 30 degrees C. These results suggest that the optimal temperatures for cell growth are between 24 degrees C and 27 degrees C, whereas those for xanthan formation are between 30 degrees C and 33 degrees C. For single-stage batch fermentation, the optimal temperature for xanthan fermentation is thus dependent on the design criteria (i. e., fermentation rate, xanthan yield, and gum qualities). However, a two-stage fermentation process with temperature shift-up from 27 degrees C to 32 degrees C is suggested to optimize both cell growth and xanthan formation, respectively, at each stage, and thus to improve overall xanthan fermentation.     

Rearing temperature enhances hepatic glucokinase but not glucose-6-phosphatase activities in European sea bass (Dicentrarchus labrax) and gilthead sea bream (Sparus aurata) juveniles fed with the same level of glucose

The aim of this work was to elucidate if the previous results observed in hepatic glucokinase (GK) and glucose-6-phosphatase (G6Pase) activities in European sea bass and gilthead sea bream are due to temperature per se or to differences in feed intake at different water temperatures. For that purpose triplicate groups of fish (30 g initial body weight) were kept at 18 degrees C or 25 degrees C during two weeks and fed a fixed daily ration of a glucose-free or 20% glucose diet. At the end of the experimental period, plasma glucose levels in both species were not influenced by water temperature but were higher in fish fed the glucose diet. Higher hepatic GK activity was observed in the two fish species fed the glucose diet than the glucose-free diet. In the glucose fed groups, GK activity was higher at 25 degrees C than at 18 degrees C. Glucose-6-phosphatase activities in both species were not influenced by water temperature. In European sea bass and in contrast to gilthead sea bream it was observed an effect of dietary composition on G6Pase activities with surprising higher activities recorded in fish fed the glucose diet than in fish fed the glucose-free diet. Overall, our data strongly suggest that European sea bass and gilthead sea bream are apparently capable to strongly regulate glucose uptake by the liver but not glucose synthesis, which is even enhanced by dietary glucose in European sea bass. Within limits, increasing water temperature enhances liver GK but not G6Pase activities, suggesting that both species are more able to use dietary carbohydrates at higher rearing temperatures.     

Temperature dependence of growth and membrane-bound activities of Chloroflexus aurantiacus energy metabolism

The temperature dependence of various activities related to the energy metabolism of isolated membranes and whole cells of the thermophilic bacterium Chloroflexus aurantiacus was determined after phototrophic growth at either 40, 50, or 60 degrees C. The data obtained were expressed by use of Arrhenius plots. Maximum activities were determined at about 65 degrees C for succinate 2,4-dichlorophenol-indophenol reductase as well as NADH oxidase and at about 70 degrees C for Mg-ATPase and for light-induced proton extrusion by cells. Activation energies for Mg-ATPase and light-induced proton extrusion were about 40 kJ mol-1 from 30 degrees C to about 50 degrees C and they increased significantly at higher temperatures. Essentially the same dependency was detectable with NADH oxidase, except for an increase in activation energy below 41 degrees C. All of these responses were independent of growth temperature. Succinate-2,4-dichlorophenol-indophenol reductase showed a change in activation energy around 41 degrees C only with cells grown at 60 degrees C. Differences in the responses of cells grown at different temperatures were identified on the basis of changes from sigmoidal to hyperbolic kinetics for light saturation of proton extrusion. Moreover, the thermostability of proton extrusion was maximal when assayed at the corresponding growth temperatures. In any case, thermostability was lowest at the 65 and 68 degrees C assay temperatures. Differential scanning calorimetry with membranes revealed irreversible heat uptake from about 60 to 72 degrees C. The results are discussed in light of the activation energy for the specific growth rate, which is lowest at temperatures from 40 degrees C to the optimum at 60 degrees C.     

Metabolic control of the membrane fluidity in Bacillus subtilis during cold adaptation

Membrane fluidity adaptation to the low growth temperature in Bacillus subtilis involves two distinct mechanisms: (1) long-term adaptation accomplished by increasing the ratio of anteiso- to iso-branched fatty acids and (2) rapid desaturation of fatty acid chains in existing phospholipids by induction of fatty acid desaturase after cold shock. In this work we studied the effect of medium composition on cold adaptation of membrane fluidity. Bacillus subtilis was cultivated at optimum (40 degrees C) and low (20 degrees C) temperatures in complex medium with glucose or in mineral medium with either glucose or glycerol. Cold adaptation was characterized by fatty acid analysis and by measuring the midpoint of phospholipid phase transition T(m) (differential scanning calorimetry) and membrane fluidity (DPH fluorescence polarization). Cells cultured and measured at 40 degrees C displayed the same membrane fluidity in all three media despite a markedly different fatty acid composition. The T(m) was surprisingly the highest in the case of a culture grown in complex medium. On the contrary, cultivation at 20 degrees C in the complex medium gave rise to the highest membrane fluidity with concomitant decrease of T(m) by 10.5 degrees C. In mineral media at 20 degrees C the corresponding changes of T(m) were almost negligible. After a temperature shift from 40 to 20 degrees C, the cultures from all three media displayed the same adaptive induction of fatty acid desaturase despite their different membrane fluidity values immediately after cold shock.     

Adaptation of Psychrophilic and Psychrotrophic Sulfate-Reducing Bacteria to Permanently Cold Marine Environments

The potential for sulfate reduction at low temperatures was examined in two different cold marine sediments, Mariager Fjord (Denmark), which is permanently cold (3 to 6(deg)C) but surrounded by seasonally warmer environments, and the Weddell Sea (Antarctica), which is permanently below 0(deg)C. The rates of sulfate reduction were measured by the (sup35)SO(inf4)(sup2-) tracer technique at different experimental temperatures in sediment slurries. In sediment slurries from Mariager Fjord, sulfate reduction showed a mesophilic temperature response which was comparable to that of other temperate environments. In sediment slurries from Antarctica, the metabolic activity of psychrotrophic bacteria was observed with a respiration optimum at 18 to 19(deg)C during short-term incubations. However, over a 1-week incubation, the highest respiration rate was observed at 12.5(deg)C. Growth of the bacterial population at the optimal growth temperature could be an explanation for the low temperature optimum of the measured sulfate reduction. The potential for sulfate reduction was highest at temperatures well above the in situ temperature in all experiments. The results from sediment incubations were compared with those obtained from pure cultures of sulfate-reducing bacteria by using the psychrotrophic strain ltk10 and the mesophilic strain ak30. The psychrotrophic strain reduced sulfate optimally at 28(deg)C in short-term incubations, even though it could not grow at temperatures above 24(deg)C. Furthermore, this strain showed its highest growth yield between 0 and 12(deg)C. In contrast, the mesophilic strain ak30 respired and grew optimally and showed its highest growth yield at 30 to 35(deg)C.     

温度对谷胱甘肽分批发酵的影响及动力学模型

研究了24～32℃范围内产朊假丝酵母生产谷胱甘肽的分批发酵过程,发现较高温度对细胞生长有促进作用,而较低温度则更有利于谷胱甘肽产量的提高。应用改进的Logistic和LuedekingPiret方程分别对细胞生长动力学和谷胱甘肽合成动力学进行了模拟,得到不同温度下各种动力学参数。在此基础上,进一步研究了温度同细胞生长动力学参数之间的内在联系,得到谷胱甘肽分批发酵过程中细胞浓度的变化同温度以及底物浓度之间的一般关系式：dX-dt＝［0.0224(T+1.7)］2X(1-X/X_max)1+S｛8.26×10.6×exp［-31477/R/(T+273)］｝。验证实验结果表明,该模型具有很好的适用性。