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1.
Om Prakash Mahe Talat Syed Hadi Hasan 《Journal of Molecular Catalysis .B, Enzymatic》2009,56(4):265-271
Soluble and alginate immobilized urease was utilized for detection and quantitation of mercury in aqueous samples. Urease from the seeds of pumpkin, being a vegetable waste, was extracted and purified to apparent homogeneity (sp. activity 353 U/mg protein; A280/A260 = 1.12) by heat treatment at 48 ± 0.1 °C and gel filtration through Sephadex G-200. Homogeneous enzyme preparation was immobilized in 3.5% alginate leading to 86% immobilization, no leaching of enzyme was found over a period of 15 days at 4 °C. Urease catalyzed urea hydrolysis by soluble and immobilized enzyme revealed a clear dependence on the concentration of Hg2+. Inhibition caused by Hg2+ was non-competitive (Ki = 1.2 × 10−1 μM for soluble and 1.46 × 10−1 μM for alginate immobilized urease.). Time-dependent inhibition both in presence and in absence of Hg2+ ion revealed a biphasic inhibition in activity. For optimization of this process response surface methodology (RSM) was utilized where two-level-two-full factorial (22) central composite design (CCD) has been employed. The regression equation and analysis of variance (ANOVA) were obtained using MINITAB® 15 software. Predicted values thus obtained were closed to experimental value indicating suitability of the model. 3D response surface plot, iso-response contour plot and process optimization curve were helpful to predict the results by performing only limited set of experiments. 相似文献
2.
The rheological properties of solutions of gellan were examined at high concentrations where there is entanglement coupling between gellan chains. An ionic liquid 1-butyl-3-methylimidazolium chloride (BmimCl) was used as a solvent. Concentrated solutions of gellan in BmimCl were obtained by using a hot-molding technique. The concentration of gellan was varied from 1.9 × 102 to 4.8 × 102 kg m−3. The measurement temperature ranged from 50 to 100 °C. The master curve of the angular frequency dispersion of the storage modulus for the gellan solutions showed a rubbery plateau at high angular frequency. The molecular weight between entanglements (Me) for gellan was obtained from the plateau modulus. From the concentration dependence curve of Me, Me for gellan in the molten state was determined to be 2.3 × 103. 相似文献
3.
In this study, the hydraulic conductivity (Lp), Me2SO permeability (
Me2SO), and the reflection coefficients (ς) and their activation energies were determined for Metaphase II (MII) mouse oocytes by exposing them to 1.5 M Me2SO at temperatures of 30, 20, 10, 3, 0, and −3°C. These data were then used to calculate the intracellular concentration of Me2SO at given temperatures. Individual oocytes were immobilized using a holding pipette in 5 μl of an isosmotic PBS solution and perfused with precooled or prewarmed 1.5 M Me2SO solutions. Oocyte images were video recorded. The cell volume changes were calculated from the measurement of the diameter of the oocytes, assuming a spherical shape. The initial volume of the oocytes in the isoosmotic solution was considered 100%, and relative changes in the volume of the oocytes after exposure to the Me2SO were plotted against time. Mean (means ± SEM) Lpvalues in the presence of Me2SO (
Me2SOp) at 30, 20, 10, 3, 0, and −3°C were determined to be 1.07 ± 0.03, 0.40 ± 0.02, 0.18 ± 0.01, 7.60 × 10−2± 0.60 × 10−2, 5.29 × 10−2± 0.40 × 10−2, and 3.69 × 10−2± 0.30 × 10−2μm/min/atm, respectively. The
Me2SOvalues were 3.69 × 10−3± 0.3 × 10−3, 1.07 × 10−3± 0.1 × 10−3, 2.75 × 10−4± 0.15 × 10−4, 7.83 × 10−5± 0.50 × 10−5, 5.24 × 10−5± 0.50 × 10−5, and 3.69 × 10−5± 0.40 × 10−5cm/min, respectively. The ς values were 0.70 ± 0.03, 0.77 ± 0.04, 0.81 ± 0.06, 0.91 ± 0.05, 0.97 ± 0.03, and 1 ± 0.04, respectively. The estimated activation energies (Ea) for
Me2SOp,
Me2SO, and ς were 16.39, 23.24, and −1.75 Kcal/mol, respectively. These data may provide the fundamental basis for the development of more optimal cryopreservation protocols for MII mouse oocytes. 相似文献
4.
Galactomannans isolated from legume seed endosperms, including those of commercial interest, have been characterized by multidetection aqueous SEC. Galactomannans derived from seeds of the Faboideae subfamily had substantially higher Mw than those from Caesalpinioideae seeds (Mw,Fab = 2.4–3.1 × 106 g/mol, Mw,Caes. = 0.86–2.1 × 106 g/mol) and within the latter botanical subfamily, an apparent correlation between Mw and the degree of galactose substitution DG was found. The molar mass distributions were unimodal and differed primarily by a scale factor, with distributional widths narrower than a true Flory ‘most-probable distribution’; good fits to Schulz–Zimm model were obtained. Across subfamilies no differences were found in the exponents of [η]–M and Rv–M relationships (0.61 ± 0.02, 0.54 ± 0.01, respectively), the Flory chain stiffness ratio (C∞ = 20 ± 1 (BSF analysis)), or the persistence length (Lp = 5.5 ± 0.2 nm) obtained from SEC fraction data. However, it was found that prefactors in the [η]–M and Rv–M relationships as well as the unperturbed parameter KΘ decrease in proportion to DG and therefore chain density. Generalized relationships incorporating galactose-dependent prefactors were therefore developed to model SEC fraction data of native galactomannans ([η]GM = (1800 ± 200) × Mo−1.61 × M0.61±0.02, Rv,GM = 0.63 ± 0.05 × Mo−0.54 × M0.54±0.01) as well as lower-M fractions obtained by ultrasonication ([η]GM = (730 ± 100) × Mo−1.71 × Mw0.71±0.02, Rv,GM = 0.49 ± 0.05 × Mo−0.57 × Mw0.57±0.01, M ≈ 1 × 105-native). As a consequence of this dependence and the observed patterns in molar mass variation, [η] varies within a narrow range for galactomannans as a whole despite substantial Mw differences. 相似文献
5.
Toshiaki Mori Momoko Toyoda Tatsuro Ohtsuka Yoshio Okahata 《Analytical biochemistry》2009,395(2):211-216
A biotinylated mannotriose (Man3-bio) was dispersively immobilized in the matrix of biotinylated lactose (Gal-Glc-bio) on a streptavidin-covered, 27-MHz quartz crystal microbalance (QCM), and binding kinetics of concanavalin A (Con A) to Man3-bio in the Gal-Glc-bio matrix could be obtained from frequency decreases (mass increases) of the QCM. Association constants (Ka) and binding and dissociation rate constants (kon and koff) could be determined separately as the 1:1 and 1:2 bindings of Con A to Man3-bio on the surface. When Man3-bio was immobilized with content of 1 to 5 mol% in the matrix, the 1:1 binding of Con A to Man3-bio was obtained as Ka = (4 ± 1) × 106 M−1, kon = (4 ± 1) × 104 M−1 s−1, and koff = (12 ± 2) × 10–3 s−1. On the contrary, when Man3-bio was immobilized with content of 20 to 100 mol% in the matrix, the 1:2 binding of Con A to Man3-bio was obtained as Ka = (14 ± 2) × 106 M−1, kon = (14 ± 2) × 104 M−1 s−1, and koff = (7 ± 2) × 10–3 s−1. Thus, Ka for the 1:2 binding was 10 times larger than that for the 1:1 binding, with a three times larger binding rate constant (kon) and a three times smaller dissociation rate constant (koff). This is the first example to obtain separate kinetic parameters for the 1:1 and 1:2 bindings of lectins to carbohydrates on the surface. 相似文献
6.
Biosurfactants have gained attention because they exhibit some advantages such as biodegradability, low toxicity, ecological acceptability and ability to be produced from renewable and cheaper substrates. They are widely used for environmental applications for bioremediation and also in biomedical field. However, the high cost of production is the limiting factor for widespread industrial applications. Thus, optimization of the growth medium for biosurfactant-lichenysin production by Bacillus licheniformis R2 was carried out using response-surface methodology. A preliminary screening phase based on a two-level fractional factorial design led to the identification of NH4NO3, glucose, Na2HPO4 and MnSO4·4H2O concentrations as the most significant variables affecting the fermentation process. The 24 full-factorial central composite design was then applied to further optimize the biosurfactant production. The optimal levels of the aforementioned variables were (g/l): NH4NO3, 1.0; glucose, 34.0; KH2PO4, 6.0; Na2HPO4, 2.7; MgSO4·7H2O, 0.1; CaCl2, 1.2 × 10−3; FeSO4·7H2O, 1.65 × 10−3; MnSO4·4H2O, 1.5 × 10−3 and Na–EDTA, 2.2 × 10−3. With the optimization procedure, the relative lichenysin yield expressed as the critical micelle dilution (CMD) was fourfold higher than that obtained in the non-optimized reference medium. 相似文献
7.
Kamila dos Santos Maguerroski Suellen Cadorin Fernandes Ana Cristina Franzoi Iolanda Cruz Vieira 《Enzyme and microbial technology》2009,44(6-7):400-405
A biosensor based on the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMI·Tf2N) and a novel source of peroxidase (tissue from the pine nuts of Araucaria angustifolia) was constructed. This enzyme was immobilized on chitosan crosslinked with citrate and the biosensor used for the determination of rosmarinic acid by square-wave voltammetry. The peroxidase in the presence of hydrogen peroxide catalyzes the oxidation of rosmarinic acid to quinone and the electrochemical reduction of the product was obtained at a potential of +0.15 V vs. Ag/AgCl. Different analytical parameters influencing the biosensor response, that is, peroxidase units, pH, hydrogen peroxide concentration and parameters for the square-wave voltammetry (frequency, pulse amplitude and scan increment), were investigated. The best performance was observed for the biosensor under the following conditions: 1000 units mL−1 peroxidase, pH 7.0 and 8.3 × 10−4 mol L−1 hydrogen peroxide with a frequency of 30 Hz, pulse amplitude of 100 mV and scan increment of 5.0 mV. The biosensor gave a linear response to rosmarinic acid over the concentration range of 9.07 × 10−7 to 4.46 × 10−6 mol L−1 with a detection limit of 7.25 × 10−8 mol L−1. The recovery of rosmarinic acid in plant extracts ranged from 97.0% to 109.6% and the determination of this substance in these samples using the biosensor compared favorably with that using the capillary electrophoresis method. 相似文献
8.
Sandeep Kumar Alka Dwevedi Arvind M. Kayastha 《Journal of Molecular Catalysis .B, Enzymatic》2009,58(1-4):138-145
The soybean (Glycine max) urease was immobilized on alginate and chitosan beads and various parameters were optimized and compared. The best immobilization obtained were 77% and 54% for chitosan and alginate, respectively. A 2% chitosan solution (w/v) was used to form beads in 1N KOH. The beads were activated with 1% glutaraldehyde and 0.5 mg protein was immobilized per ml of chitosan gel for optimum results. The activation and coupling time were 6 h and 12 h, respectively. Further, alginate and soluble urease were mixed to form beads and final concentrations of alginate and protein in beads were 3.5% (w/v) and 0.5 mg/5 ml gel. From steady-state kinetics, the optimum temperature for urease was 65 °C (soluble), 75 °C (chitosan) and 80 °C (alginate). The activation energies were found to be 3.68 kcal mol−1, 5.02 kcal mol−1, 6.45 kcal mol−1 for the soluble, chitosan- and alginate-immobilized ureases, respectively. With time-dependent thermal inactivation studies, the immobilized urease showed improved stability at 75 °C and the t1/2 of decay in urease activity was 12 min, 43 min and 58 min for soluble, alginate and chitosan, respectively. The optimum pH of urease was 7, 6.2 and 7.9 for soluble, alginate and chitosan, respectively. A significant change in Km value was noticed for alginate-immobilized urease (5.88 mM), almost twice that of soluble urease (2.70 mM), while chitosan showed little change (3.92 mM). The values of Vmax for alginate-, chitosan-immobilized ureases and soluble urease were 2.82 × 102 μmol NH3 min−1 mg−1 protein, 2.65 × 102 μmol NH3 min−1 mg−1 protein and 2.85 × 102 μmol NH3 min−1 mg−1 protein, respectively. By contrast, reusability studies showed that chitosan–urease beads can be used almost 14 times with only 20% loss in original activity while alginate–urease beads lost 45% of activity after same number of uses. Immobilized urease showed improved stability when stored at 4 °C and t1/2 of urease was found to be 19 days, 80 days and 121 days, respectively for soluble, alginate and chitosan ureases. The immobilized urease was used to estimate the blood urea in clinical samples. The results obtained with the immobilized urease were quite similar to those obtained with the autoanalyzer®. The immobilization studies have a potential role in haemodialysis machines. 相似文献
9.
S. Subramanian G. Santharam N. Sathiah J.S. Kennedy R.J. Rabindra 《Biological Control》2006,37(3):367-374
Mass production of baculoviruses by in vivo methods is influenced by several factors like larval age at virus treatment, virus concentration and the incubation temperature. The larval age at virus treatment and virus concentration should be synchronized to result in insect death at a fully grown larval stage to maximize the productivity. Since temperature influences both the growth of the larvae and replication of the virus, we evaluated the influence of incubation temperature on mass production of Spodoptera litura nucleopolyhedrovirus (SpltNPV) at four different temperature regimes viz., 25, 30, and 35 °C and room temperature by diet-surface contamination method. Incubation of early fifth instar larvae dosed with 3932.4 polyhedral inclusion bodies (PIB)/mm2 at 25 °C enhanced the virus productivity to 6.623 × 1011 PIB yield/100 inoculated larvae, while it was only 1.779 × 1011 at 35 °C. The disease progression in the virus treated larvae was slow with median lethal time (LT50) of 208 h at 25 °C as compared to 136 h at 35 °C. In spite of the slow death which means lower production cycles/year, the productivity/year was higher at 25 °C than at other temperatures. The SpltNPV produced at 25 °C was also found to be of superior quality in terms of low bacterial contaminants than at 35 °C. Neonate larval bioassay conducted with viruses produced at different temperature treatments revealed that they were similar in their activity and virulence. Hence our results indicate that maintenance of the SpltNPV production facility at 25 °C would enhance both the virus productivity and quality. 相似文献
10.
E. Quesada-Moraga E.A.A. Maranhao P. Valverde-García C. Santiago-lvarez 《Biological Control》2006,36(3):274-287
As part of a 3-fold approach to select potential mycoinsecticides for whitefly control, we evaluated infectivity, thermal requirements, and toxicogenic activity of the entomopathogenic fungus Beauveria bassiana (Ascomycota: Clavicipitaceae) under laboratory conditions. Twenty-five native B. bassiana isolates and a commercially available mycoinsecticide (based on B. bassiana) were evaluated for virulence to fourth instar nymphs of sweetpotato whitefly, Bemisia tabaci, and greenhouse whitefly, Trialeurodes vaporariorum, at a concentration of 1 × 107 conidia/ml. All isolates were pathogenic for both whitefly species, whereas mortality rates varied from 3 to 85%. A second series of bioassays was conducted on 10 selected isolates using four 10-fold concentrations ranging from 1 × 105 to 1 × 108 conidia/ml. Median lethal concentrations (LC50) of the four most virulent isolates varied from 1.1 × 105 to 6.2 × 106 conidia/ml and average survival time (AST) of treated nymphs from 5.9 to 7.4 days. T. vaporariorum were significantly more susceptible to all B. bassiana isolates than B. tabaci. The thermal biology of the eight most virulent isolates to both whitefly species was investigated at six temperatures (10–35 °C). The colony radial growth rate was estimated from the slope of the linear regression of colony radius on time and data were then fitted to a modified generalized β function that accounted for 90.5–99.3% of the data variance. Optimum temperatures for extension rate ranged from 23.1 to 27.1 °C, whereas maximum temperatures for fungal growth varied from 31.8 to 36.6 °C. On the basis of their virulence and thermal requirements, three isolates showed promise as candidates for whitefly management in Mediterranean greenhouses. Whilst in vitro production of macromolecular compounds toxic to Galleria mellonella larvae was not a requisite for virulence, ASTs of larvae injected with Sephadex G-25 fractions from candidate isolates ranged from 1.4 to 3.7 days compared with 5–6 days for non-toxic G-25 fractions. In addition, proteinase K treatment significantly reduced their toxic activity suggesting that they were proteins and revealing the potential of these isolates to be further improved through biotechnology to kill the pest more quickly. 相似文献
11.
Hui-Ling Ma Selim Kermasha Jin-Ming Gao Rogelio Morales Borges Xiu-zhu Yu 《Journal of Molecular Catalysis .B, Enzymatic》2009,57(1-4):89-95
Rhus vernificera laccase-catalyzed oxidation of phenolic compounds, i.e., (+)-catechin, (−)-epicatechin and catechol, was carried out in selected organic solvents to search for the favorable reaction medium. The investigation on reaction parameters showed that optimal laccase activity was obtained in hexane at 30 °C, pH 7.75 for the oxidation of (+)-catechin as well as for (−)-epicatechin, and in toluene at 35 °C, pH 7.25 for the oxidation of catechol. Ea and Q10 values of the biocatalysis in the reaction media of the larger log p solvents like isooctane and hexane were relatively higher than those in the reaction media of lower log p solvents like toluene and dichloromethane. Maximum laccase activity in the organic media was found with 6.5% of buffer as co-solvent. A wider range of 0–28 μg protein/ml in hexane than that of 0–16.7 μg protein/ml in aqueous medium was observed for the linear increasing conversion of (+)-catechin. The kinetic studies revealed that in the presence of isooctane, hexane, toluene and dichloromethane, the Km values were 0.77, 0.97, 0.53 and 2.9 mmol/L for the substrate of (+)-catechin; 0.43, 0.34, 0.14 and 3.4 mmol/L for (−)-epicatechin; 2.9, 1.8, 0.61 and 1.1 mmol/L for catechol, respectively, while the corresponding Vmax values were 2.1 × 10−2, 2.3 × 10−2, 0.65 × 10−2 and 0.71 × 10−2 δA/μg protein min); 1.8 × 10−2, 0.88 × 10−2, 0.19 × 10−2 and 1.0 × 10−2 δA/μg protein min); 0.48 × 10−2, 0.59 × 10−2, 0.67 × 10−2 and 0.54 × 10−2 δA/μg protein min), respectively. FT-IR indicated the formation of probable dimer from (+)-catechin in organic solvent. These results suggest that this laccase has higher catalytic oxidation capacity of phenolic compounds in suitable organic media and favorite oligomers could be obtained. 相似文献
12.
Padmarajaiah Nagaraja Anantharaman Shivakumar Ashwinee Kumar Shrestha 《Analytical biochemistry》2009,395(2):231-236
A sensitive, selective, and rapid enzymatic method is proposed for the quantification of hydrogen peroxide (H2O2) using 3-methyl-2-benzothiazolinonehydrazone hydrochloride (MBTH) and 10,11-dihydro-5H-benz(b,f)azepine (DBZ) as chromogenic cosubstrates catalyzed by horseradish peroxidase (HRP) enzyme. MBTH traps free radical released during oxidation of H2O2 by HRP and gets oxidized to electrophilic cation, which couples with DBZ to give an intense blue-colored product with maximum absorbance at 620 nm. The linear response for H2O2 is found between 5 × 10−6 and 45 × 10−6 mol L−1 at pH 4.0 and a temperature of 25 °C. Catalytic efficiency and catalytic power of the commercial peroxidase were found to be 0.415 × 106 M−1 min−1 and 9.81 × 10−4 min−1, respectively. The catalytic constant (kcat) and specificity constant (kcat/Km) at saturated concentration of the cosubstrates were 163.2 min−1 and 4.156 × 106 L mol−1 min−1, respectively. This method can be incorporated into biochemical analysis where H2O2 undergoes catalytic oxidation by oxidase. Its applicability in the biological samples was tested for glucose quantification in human serum. 相似文献
13.
Renoguanylin (REN) is a recently described member of the guanylin family, which was first isolated from eels and is expressed in intestinal and specially kidney tissues. In the present work we evaluate the effects of REN on the mechanisms of hydrogen transport in rat renal tubules by the stationary microperfusion method. We evaluated the effect of 1 μM and 10 μM of renoguanylin (REN) on the reabsorption of bicarbonate in proximal and distal segments and found that there was a significant reduction in bicarbonate reabsorption. In proximal segments, REN promoted a significant effect at both 1 and 10 μM concentrations. Comparing control and REN concentration of 1 μM, JHCO3−, nmol cm− 2 s− 1 − 1,76 ± 0,11control × 1,29 ± 0,08REN 10 μM; P < 0.05, was obtained. In distal segments the effect of both concentrations of REN was also effective, being significant e.g. at a concentration of 1 μM (JHCO3−, nmol cm− 2 s− 1 − 0.80 ± 0.07control × 0.60 ± 0.06REN 1 μM; P < 0.05), although at a lower level than in the proximal tubule. Our results suggest that the action of REN on hydrogen transport involves the inhibition of Na+/H+exchanger and H+-ATPase in the luminal membrane of the perfused tubules by a PKG dependent pathway. 相似文献
14.
We studied the process of conversion of microcrystalline-cellulose into fermentable glucose in the formic acid reaction system using cross polarization/magic angle spinning 13C-nuclear magnetic resonance, X-ray diffraction and Fourier transform infrared spectroscopy. The results indicated that formic acid as an active agent was able to effectively penetrate into the interior space of the cellulose molecules, thus collapsing the rigid crystalline structure and allowing hydrolysis to occur easily in the amorphous zone as well as in the crystalline zone. The microcrystalline-cellulose was hydrolyzed using formic acid and 4% hydrochloric acid under mild conditions. The effects of hydrochloric acid concentration, the ratio of solid to liquid, temperature (55–75 °C) and retention time (0–9 h), and the concentration of glucose were analyzed. The hydrolysis velocities of microcrystalline-cellulose were 6.14 × 10− 3 h− 1 at 55 °C, 2.94 × 10− 2 h− 1 at 65 °C, and 6.84 × 10− 2 h− 1 at 75 °C. The degradation velocities of glucose were 0.01 h− 1 at 55 °C, 0.14 h− 1 at 65 °C, 0.34 h− 1 at 75 °C. The activation energy of microcrystalline-cellulose hydrolysis was 105.61 kJ/mol, and the activation energy of glucose degradation was 131.37 kJ/mol. 相似文献
15.
Peroxidase catalyzed phenolic compounds oxidation in presence of surfactant Dynol 604: A kinetic investigation 总被引:1,自引:0,他引:1
The kinetics of fungal peroxidase-catalyzed phenolic compounds (PCs) oxidation was investigated in presence of acetylenic-based surfactant Dynol 604 at pH 5.5 and 25 °C. It was shown that the presence of ppm concentrations of surfactant did not influence initial rate of PCs oxidation. The calculated apparent bimolecular rate constants were (1.8 ± 0.2) × 105 M−1 s−1, (1.4 ± 0.4) × 107 M−1 s−1, (1.30 ± 0.06) × 107 M−1 s−1 and 1.1 × 108 M−1 s−1 for phenol, 1-naphthol, 2-naphthol and 1-hydroxypyrene, respectively.During an extensive substrates conversion Dynol 604 showed diverse action for different PCs. The oxidation of phenol practically did not change, whereas the surfactant enhanced the conversion of 1- and 2-naphthol and 1-hydroxypyrene in dose response manner. The results accounted by a scheme, which contains a stadium of enzyme inhibition by oligomeric PC oxidation products. The action of the surfactant was explained by avoidance the enzyme active center clothing with the oligomers. The results acquired demonstrate a remarkable increase of substrates conversion in the presence of Dynol 604. 相似文献
16.
Cryopreservation of human adipose tissues 总被引:2,自引:1,他引:1
Scientific studies on cryopreservation of adipose tissues have seldom been performed. The purpose of our present study is conducted both in vitro and in vivo to develop a novel cryopreservation method that can be used successfully for long-term preservation of human adipose tissues for possible future clinical application. In this study, samples of adipose aspirates were obtained from 36 adult white female patients after liposuction and collected from the middle layer after centrifugation. In the in vitro study, suitable cryoprotectant agents (CPAs) and their concentrations and possible combinations were selected from our preliminary experiment. A combination of dimethyl sulfoxide (Me2SO) and trehalose as CPA with the optimal concentration (0.5 M Me2SO and 0.2 M trehalose) was chosen and then used throughout the study. In addition, maximal recovery of adipose tissues was achieved after cryopreservation using slow cooling without seeding (1–2 °C/min to −30 °C, followed by plunging to −196 °C for storage) and fast warming (in 40 °C water bath, averaging 35 °C/min). Fresh adipose aspirates (Group 1), cryopreserved adipose aspirates without CPAs (Group 2), or cryopreserved adipose aspirates with CPAs (Group 3) were evaluated by integrated adipocyte counts and histology. In the in vivo study, fresh adipose aspirates (Group 1), cryopreserved adipose aspirates without CPAs (Group 2), or cryopreserved adipose aspirates with CPAs (Group 3) were injected into a nude mouse. The retained adipose aspirates (fat grafts) were harvested in each animal at 4 months and their weight, volume, and histology was assessed. In the in vitro study, significantly higher integrated viable adipocyte count (2.06 ± 0.54 × 106 mL−1 vs. 1.07 ± 0.41 × 106 mL−1, p < 0.0011) of adipose aspirates was found in Group 3 compared with Group 2. Group 3 had only a marginally lower integrated viable adipocyte count compared with Group 1 (2.06 ± 0.54 ×106 mL−1 vs. 2.57 ± 0.56 × 106 mL−1, p = 0.083). Histologically, more tissue shrinkage was evident in Group 2 compared with Group 3. In the in vivo study, various degrees of absorption of injected fat grafts were seen in all 3 groups. However, Group 3 had significantly more retained weight and volume of the injected fat grafts than Group 2 (both p < 0.0001) but had significantly less retained weight and volume than Group 3 (weight, p = 0.009178; volume, p = 0.007836). Histologically, a large amount of tissue fibrosis was seen in Group 2, and reasonably well maintained fatty tissue with only a small amount of tissue fibrosis was seen in Group 3. The results from the present in vitro and in vivo studies, for the first time, demonstrate that our preferred cryopreservation method, the combination of 0.5M Me2SO and 0.2 M trehalose as CPA in addition to the controlled slow cooling and fast rewarming protocol, appears to provide the maximum recovered results in cryopreservation of human adipose tissues and may become a real option after further refinements for cryopreservation of human adipose aspirates in a clinical setting. 相似文献
17.
The rate constant for the hydrolysis of prostacyclin (PGI2) to 6-keto-PGF1α was measured by monitoring the UV spectral change, over a pH range 6 to 10 at 25°C and the total ionic strength of 0.5 M. The first-order rate constant (kobs) extrapolated to zero buffer concentration follows an expression, kobs = kH+ (H+), where kH+ is a second-order rate constant for the specific acid catalyzed hydrolysis. The value of kH+ obtained (3.71 × 104 sec−1 M−1) is estimated approximately 700-fold greater than a kH+ value expected from the hydrolysis of other vinyl ethers. Such an unusually high reactivity of PGI2 even for a vinyl ether is attributed to a possible ring strain release that would occur upon the rate controlling protonation of C5. A Brønsted slope (α) of 0.71 was obtained for the acid (including H3O+) catalytic constants, from which a pH independent first-order rate constant for the spontaneous hydrolysis (catalyzed by H2O as a general acid) was estimated to be 1.3 × 10−6 sec−1. An apparent activation energy (Ea) of 11.85 Kcal/mole was obtained for the hydrolysis at pH 7.48, from which a half-life of PGI2 at 4°C was estimated to be approximately 14.5 min. when the total phosphate concentration is 0.165 M (cf. 3.5 min. at 25°C). 相似文献
18.
The characteristics of morphometric (body length and width), biochemical (fatty acid content), motility, and penetration rate of infective juveniles ofSteinernema carpocapsaeBeijing strain reared on four different culture media [e.g., plant protein medium (I), animal protein medium (II), plant and animal protein medium (III), andin vivoculture (IV) were systematically compared in this research. The results showed that the average lengths of infective juveniles were 497.4 ± 0.09, 514.3 ± 0.08, 525.7 ± 0.09, and 556.6 ± 0.09 μm, the average widths were 24.9 ± 0.006, 25.6 ± 0.005, 26.1 ± 0.006, and 27.9 ± 0.004 μm, and the average dry weights per million infective juveniles were 49.2 ± 2.2, 58.6 ± 2.4, 59.6 ± 1.8, and 80.7 ± 1.7 mg cultured by media I, II, III, and IV, respectively. The highest relative content of fatty acid of infective juveniles was obtained from medium IV at 15.4 ± 1.2 × 105μV/s, and the lowest one was 6.76 ± 0.3 × 105μV/s from medium I and 11.8 ± 0.2 × 105and 13.7 ± 0.3 × 105μV/s from media II and III, respectively. The numbers of nematodes that moved a vertical distance of 5 cm in sand column within 48 h were 24 ± 3.6, 75 ± 11.6, 69 ± 9.7, and 92 ± 13.2 and the penetration rates into theGallerialarva within 24 h were 2.8 ± 0.45, 6.0 ± 1.14, 6.4 ± 0.74, and 6.0 ± 0.7% from media I to IV, respectively. The results indicated that the quality of entomopathogenic nematode was influenced by the cultural medium component. The animal protein, especially from insects which were presented in media II, III, and IV, has a strong positive effect on nematode quality. 相似文献
19.
zlem Alptekin S. Seyhan Tükel Deniz Yldrm Dilek Alagz 《Journal of Molecular Catalysis .B, Enzymatic》2009,58(1-4):124-131
Bovine liver catalase was covalently immobilized onto controlled pore glass (CPG) beads modified with 3-aminopropyltriethoxysilane (3-APTES) followed by treatment with glutaraldehyde. Coupling of catalase onto CPG was optimized to improve the efficiency of the overall immobilization procedure. The optimum coupling conditions: pore diameter of CPG, pH, buffer concentration, temperature, coupling time and initial catalase amount per grams of carrier were determined as 70 nm, 6.0, 75 mM, 5 °C, 7 h and 6 mg catalase, respectively. Catalytic efficiencies (kcat/Km) and thermal inactivation rate constants (ki) of ICPG1 were determined and compared with that of free catalase. Suitability of ICPG1 was also investigated by using it in batch and plug-flow type reactors. When the remaining activity of ICPG1 retained was about 50% of its initial activity the highest total productivity of ICPG1 was determined as 7.6 × 106 U g immobilized catalase−1 in plug-flow type reactor. However, the highest total productivity of ICPG1 was 6.2 × 105 U g immobilized catalase−1 in batch type reactor. ICPG1 may have great potentials as biocatalyst for the application in decomposition of hydrogen peroxide in plug-flow type reactor. 相似文献
20.
Charles E. Ahlfors 《Analytical biochemistry》1981,110(2):295-307
The binding of biliverdin-IXα by human albumin and serum was quantitated, using three different binding techniques, to study the effects of biliverdin on bilirubin-albumin binding. The apparent equilibrium association constants (K ± SD) and binding capacities (n) of defatted albumin, pooled adult sera, and pooled umbilical cord sera for biliverdin are: K = 1.3 ± 2 × 106
−1, n = 1.00; K = 13.0 ± 3 × 106
−1, n = 0.90; and K = 6.8 ± 0.1 × 106
−1, n = 0.85, respectively. Although bilirubin binds at more than one albumin site, competitive studies showed that biliverdin binds only at the primary (highest affinity) bilirubin site. Sulfisoxazole, previously thought to compete with bilirubin for the primary binding site, was found to displace bilirubin from both primary and secondary bilirubin binding sites. Biliverdin, because of its specific binding and spectral characteristics, could be a useful probe for determining the capacity of the primary bilirubin-albumin binding site. 相似文献