Winter provides many challenges for terrestrial arthropods, including low temperatures and decreased food availability. Most arthropods are dormant in the winter and resume activity when conditions are favorable, but a select few species remain active during winter. Winter activity is thought to provide a head start on spring growth and reproduction, but few studies have explicitly tested this idea or investigated tradeoffs associated with winter activity. Here, we detail biochemical changes in overwintering winter-active wolf spiders, Schizocosa stridulans, to test the hypothesis that winter activity promotes growth and energy balance. We also quantified levels of putative cryoprotectants throughout winter to test the prediction that winter activity is incompatible with biochemical adaptations for coping with extreme cold. Body mass of juveniles increased 3.5-fold across winter, providing empirical evidence that winter activity promotes growth and therefore advancement of spring reproduction. While spiders maintained protein content throughout most of the winter, lipid content decreased steadily, suggesting either a lack of available prey to maintain lipids, or more likely, an allometric shift in body composition as spiders grew larger. Carbohydrate content showed no clear seasonal trend but also tended to be higher at the beginning of the winter. Finally, we tested the hypothesis that winter activity is incompatible with cryoprotectant accumulation. However, we observed accumulation of glycerol, myo-inositol, and several other cryoprotectants, although levels were lower than those typically observed in overwintering arthropods. Together, our results indicate that winter-active wolf spiders grow during the winter, and while cryoprotectant accumulation was observed in the winter, the modest levels relative to other species could make them susceptible to extreme winter events.
- MeSH
- energetický metabolismus * MeSH
- fyziologická adaptace MeSH
- glycerol analýza MeSH
- index tělesné hmotnosti MeSH
- inositol analýza MeSH
- kryoprotektivní látky analýza MeSH
- lipidy analýza MeSH
- nízká teplota škodlivé účinky MeSH
- pavouci růst a vývoj metabolismus MeSH
- predátorské chování MeSH
- proteiny analýza MeSH
- roční období MeSH
- rozmnožování MeSH
- sacharidy analýza MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
Metabolism of human adipose tissue during acute exercise is monitored by microdialysis. The metabolites are analysed in the microdialysate using capillary electrophoresis (CE) on a short separation path in combination with a contactless conductivity detector (C4D). Four completely new CE/C4D methods were developed for determination of nutrients and metabolites in 10 µL of microdialysate. All methods are characterised by a short separation time and simple sample preparation based primarily on 4-fold dilution of microdialysate. The intra-day repeatability for the migration time varied in the range 0.4 - 0.9% and that for the peak area equalled 0.7 - 2.4%; the inter-day repeatability of the migration time was in the range 1.2 - 2.3% and the range for the peak area was 2.5 - 5.0%; all the values were measured as RSD. The developed determination was employed for sequenced monitoring of the levels of lactate, glycerol and branched chain amino acids in microdialysates taken from the abdominal adipose tissue during acute physical exercise. The stress test lasted 3 h and the metabolites were monitored at 15 min intervals.
- MeSH
- cvičení fyziologie MeSH
- dospělí MeSH
- elektrická vodivost MeSH
- elektroforéza kapilární metody MeSH
- glycerol analýza MeSH
- kyselina mléčná analýza MeSH
- lidé MeSH
- metabolomika metody MeSH
- mikrodialýza metody MeSH
- tuková tkáň metabolismus MeSH
- větvené aminokyseliny analýza MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
The aim of the study was to screen Yarrowia lipolytica strains for keto acid production and determine optimal conditions for pyruvic acid biosynthesis from glycerol by the best producer. The analyzed parameters were thiamine concentration, medium pH, stirring speed, and substrate concentration. The screening was performed in flask cultures, whereas pyruvic acid production was carried out in 5-L stirred-tank reactor with 2 L of working volume. In total, 24 Y. lipolytica strains were compared for their abilities to produce pyruvic and α-ketoglutaric acids. The total concentration of both acids ranged from 0.1 to 15.03 g/L. Ten strains were selected for keto acid biosynthesis in bioreactor. The Y. lipolytica SKO 6 strain was identified as the best producer of pyruvic acid. In the selected conditions (thiamine concentration 1.5 μg/L, pH 4.0, stirring speed 800 rpm, 150 g/L of glycerol), the strain Y. lipolytica SKO 6 produced 99.3 g/L of pyruvic acid, with process yield of 0.63 g/g and volumetric production rate of 1.18 g/L/h. Higher titer of pyruvic acid was obtained during fed-batch culture with 200 g/L of glycerol, reaching 125.8 g/L from pure glycerol (yield 0.68 g/g) and 124.4 g/L from crude glycerol (yield 0.62 g/g). Results obtained for the strain Y. lipolytica SKO 6 proved the suitability of microbial production of pyruvic acid at industrial scale.
- MeSH
- bioreaktory MeSH
- glycerol analýza metabolismus MeSH
- kultivační média chemie MeSH
- kyselina pyrohroznová analýza metabolismus MeSH
- kyseliny ketoglutarové analýza metabolismus MeSH
- techniky vsádkové kultivace MeSH
- thiamin analýza MeSH
- Yarrowia růst a vývoj metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
Anthropogenic halogenated compounds were unknown to nature until the industrial revolution, and microorganisms have not had sufficient time to evolve enzymes for their degradation. The lack of efficient enzymes and natural pathways can be addressed through a combination of protein and metabolic engineering. We have assembled a synthetic route for conversion of the highly toxic and recalcitrant 1,2,3-trichloropropane to glycerol in Escherichia coli, and used it for a systematic study of pathway bottlenecks. Optimal ratios of enzymes for the maximal production of glycerol, and minimal toxicity of metabolites were predicted using a mathematical model. The strains containing the expected optimal ratios of enzymes were constructed and characterized for their viability and degradation efficiency. Excellent agreement between predicted and experimental data was observed. The validated model was used to quantitatively describe the kinetic limitations of currently available enzyme variants and predict improvements required for further pathway optimization. This highlights the potential of forward engineering of microorganisms for the degradation of toxic anthropogenic compounds.
- MeSH
- bakteriální proteiny MeSH
- biodegradace * MeSH
- Escherichia coli genetika metabolismus MeSH
- genetické inženýrství MeSH
- glycerol analýza metabolismus MeSH
- látky znečišťující životní prostředí analýza metabolismus MeSH
- metabolické inženýrství metody MeSH
- metabolické sítě a dráhy MeSH
- počítačová simulace MeSH
- propan analogy a deriváty analýza metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The proposed analytical method allows for simultaneous determination by GC using a programed temperature vaporization injector and a flame ionization detector of the main reaction components (i.e. glycerol, methyl esters, mono-, di-, and triacylglycerols) in the reaction mixture during biodiesel production. The suggested method is convenient for the rapid and simple evaluation of the kinetic data gained during the transesterification reaction and, also partially serves as an indicator of the quality of biodiesel and mainly, as the indicator of the efficiency of the whole production process (i.e. the conversion of triacylglycerols to biodiesel and its time progress). The optimization of chromatographic conditions (e.g. the oven temperature program, injector setting, amount of derivatization reagent, and the derivatization reaction time) was performed. The method has been validated with crude samples of biodiesel made from waste-cooking oils in terms of linearity, precision, accuracy, sensitivity, and limits of detection and quantification. The results confirmed a satisfactory degree of accuracy and repeatability (the mean RSDs were usually below 2%) necessary for the reliable quantitative determination of all components in the considerable concentration range (e.g. 10-1100 μg/mL in case of methyl esters). Compound recoveries ranging from 96 to 104% were obtained.
A sensitive and accurate method utilizing ultrahigh performance liquid chromatography (U-HPLC) coupled to high resolution mass spectrometry based on orbitrap technology (orbitrapMS) for the analysis of nine 3-chloropropane-1,2-diol (3-MCPD) diesters in vegetable oils was developed. To remove the interfering triacylglycerols that induce strong matrix effects, a clean-up step on silica gel column was used. The quantitative analysis was performed with the use of deuterium-labeled internal standards. The lowest calibration levels estimated for the respective analytes ranged from 2 to 5 μg kg(-1). Good recovery values (89-120%) and repeatability (RSD 5-9%) was obtained at spiking levels of 2 and 10 mg kg(-1). As an alternative, a novel ambient desorption ionization technique, direct analysis in real time (DART), hyphenated with orbitrapMS, was employed for no separation, high-throughput, semi-quantitative screening of 3-MCPD diesters in samples obtained by chromatographic fractionation. Additionally, the levels of 3-MCPD diesters measured in reallife vegetable oil samples (palm oil, sunflower oil, rapeseed oil) using both methods are reported. Relatively good agreement of the data generated by U-HPLC-orbitrapMS and DART-orbitrapMS were observed. With regard to a low ionization yield achieved for 3-MCPD monoesters, the methods presented in this paper were not yet applicable for the analysis of these contaminants at the naturally occurring levels.
The distribution of ethyl esters, triglycerides, diglycerides, monoglycerides, and glycerol between the ester and glycerol phase was investigated after the ethanolysis of rapeseed oil at various reaction conditions. The determination of these substances in the ester and glycerol phases was carried out by the GC method. The amount of ethyl esters in the glycerol phase was unexpectedly high and therefore the possibility of the reduction of this amount was investigated. The distribution coefficients and the weight distributions of each investigated substance were calculated and compared mutually. The distribution coefficients between the ester and glycerol phase increase in this sequence: glycerol, monoglycerides, diglycerides, ethyl esters, and triglycerides. Soaps and monoglycerides in the reaction mixture cause a worse separation of ethyl esters from the reaction mixture. The existence of a non-separable reaction mixture was observed also, and its composition was determined.
A CE procedure employing capacitively coupled contactless conductivity detection has been developed for direct determination of the glycerol and mannitol polyalcohols in biological and pharmacological samples. Both glycerol and mannitol are fully separated from the sample matrix within very short times of 3.0 and 3.9 min, respectively, when using the optimized BGE, 60 mM H3BO3+30 mM LiOH (pH 9.1). The LODs amount to 0.5 microM for glycerol and 0.3 microM for mannitol. The repeatability of the glycerol determination in real biological materials is characterized by the coefficient of variation values, 0.5 and 3.2%, for the migration time and the peak area, respectively. The procedure has been used to monitor the free glycerol concentration in adipose tissue microdialyzates. A physiological study has demonstrated that the lipolysis occurring during a sporting action can be stimulated by local application of adrenaline. The procedure has further been utilized to determine mannitol in a pharmacological preparation.
- MeSH
- acetonitrily chemie MeSH
- cvičení fyziologie MeSH
- cyklistika fyziologie MeSH
- elektrická vodivost MeSH
- elektroforéza kapilární metody MeSH
- glycerol analýza metabolismus MeSH
- kalibrace MeSH
- koncentrace vodíkových iontů MeSH
- kyseliny borité chemie MeSH
- lidé MeSH
- lineární modely MeSH
- lipolýza fyziologie MeSH
- mannitol analýza metabolismus MeSH
- reprodukovatelnost výsledků MeSH
- senzitivita a specificita MeSH
- sloučeniny lithia chemie MeSH
- tuková tkáň chemie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Many samples of rapeseed oil ethyl ester were prepared by alkaline-catalyzed transesterification at various conditions (reaction time, temperature, amount of catalyst, the molar ratio of ethanol to oil, the rotations of a disperser and the purification by water). The concentrations of the key impurities for biodiesel quality (the concentrations of monoglycerides, diglycerides, triglycerides, free glycerol, ethanol, free fatty acids, water) and some qualitative parameters (flash point, carbon residue, kinematics viscosity at 40 degrees C) were determined and then the relationships among them were found out. The relationships were characterized by the linear or non-linear statistical models. The found models enable the better understanding of the significance of the qualitative parameters and estimate them from the concentrations of impurities. The temperature dependence was also measured in the case of the viscosity of ethyl ester and used rapeseed oil.
OBJECTIVE: The aim of this study was to monitor and compare metabolic changes in the skeletal muscle during coronary artery bypass grafting surgery with and without cardiopulmonary bypass (CPB) by means of interstitial microdialysis. Glucose, lactate, pyruvate and glycerol were assessed as markers of basic metabolism and tissue perfusion. METHODS: Twenty patients undergoing surgical myocardial revascularization were enrolled in this pilot study. Ten patients were operated on without CPB (group A, off-pump) and 10 patients using normothermic CPB (group B, on-pump). Interstitial microdialysis was performed by a CMA 60 (CMA/Microdialysis AB, Sweden) probe, inserted into the patient's left deltoid muscle. Microdialysis measurements were performed at 30 min intervals. Glucose, lactate, pyruvate and glycerol were measured in samples using a CMA 600 Analyser (CMA/Microdialysis AB, Sweden). Results in both groups were statistically processed and the groups were compared. RESULTS: Both groups were similar with regards to preoperative characteristics. Dynamic changes of interstitial concentrations of the measured analytes were found in off-pump (group A) and on-pump (group B) patients during the operation. There were no significant differences in dialysate concentrations of glucose and lactate between the groups. Significant differences were detected in pyruvate concentrations, lactate-pyruvate ratio and glycerol concentrations between off-pump versus on-pump patients. Pyruvate concentrations were higher in the off-pump group (p<0.05), the lactate-pyruvate ratios indicating the aerobic/anaerobic metabolism status were lower in the off-pump group (p<0.01) and the values of the concentrations of glycerol were lower in the off-pump group (p<0.01). CONCLUSION: Dynamic changes in the interstitial concentrations of the glucose, glycerol, pyruvate and lactate were found in both groups of patients (off-pump and on-pump). The presented preliminary results suggest that extracorporeal circulation during cardiac operations could compromise skeletal muscle energy metabolism.
- MeSH
- anastomóza chirurgická MeSH
- biologické markery analýza MeSH
- extracelulární tekutina chemie MeSH
- financování organizované MeSH
- glukosa analýza MeSH
- glycerol analýza MeSH
- kardiopulmonální bypass MeSH
- koronární bypass bez mimotělního oběhu metody MeSH
- koronární bypass metody MeSH
- koronární nemoc chirurgie krev metabolismus MeSH
- kosterní svaly metabolismus MeSH
- kyselina mléčná analýza MeSH
- kyselina pyrohroznová analýza MeSH
- lidé středního věku MeSH
- lidé MeSH
- mikrodialýza MeSH
- neparametrická statistika MeSH
- peroperační doba MeSH
- pilotní projekty MeSH
- prospektivní studie MeSH
- senioři MeSH
- vyvolaná zástava srdce MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- randomizované kontrolované studie MeSH
