共查询到20条相似文献,搜索用时 46 毫秒
1.
Summary The production of -linolenic acid (GLA) by the fungus Mucor rouxii CBS 416.77 was studied on low budget nitrogen and carbon sources, i.e. rape meal, cocos expeller and two types of yeast extract (nitrogen sources), and starch, starch hydrolysate, beet molasses and cocos expeller (carbon sources). As references, Difco yeast extract and glucose were used. In flask cultivations the three yeast extracts were fully interchangeable, while the Difco yeast extract (the most expensive of those tested) gave a higher productivity of GLA in fermentor cultures (14 mg·l–1·h–1). The yield of lipids and GLA were increased in the order yeast extract < rape meal < cocos expeller. Thus the amount of lipid increased from 0.56 to 2.8 g·l–1, and that of GLA from 0.15 to 0.33 g·l–1. Use of beet molasses or cocos expeller as carbon sources gave poor growth. Starch and starch hydrolysate resulted in better productivity of GLA than glucose (4.7 and 4.9 compared to 3.4 mg·l–1·h–1).
Offsprint requests to: A.-M. Lindberg 相似文献
2.
Clearance rates of sessile rotifers: in vitro determinations 总被引:1,自引:1,他引:0
We measured laboratory clearance rates of 10 rotifer and one unidentified bryozoan species from 3 different lakes using 32P labeled algae (Chlamydomonas) or yeast (Rhodotorula). Clearance rates for all rotifers fed yeast ranged from < 2.0 to > 260 µl · animal–1 · h–1 depending on species. The in vitro clearance rates of two sessile rotifers (Ptygura crystallina and P. pilula) were not significantly different from previously measured in situ rates (Wallace and Starkweather 1983). Clearance rates for 5 rotifers fed algae ranged from < 5.0 to > 90.0 µl · animal–1 · h–1. Ptygura beauchampi, P. crystallina, P. pilula, Floscularia conifera, and F. melicerta ingested both cell types but their clearance rates varied substantially among species and between cell types. There was a substantial time-dependent loss of 32P from formalin-fixed animals (Sinantherina socialis) awaiting processing. This loss stabilized at approximately 20 hours and was estimated to be about 40% of the initial ingested label. Clearance rates for the bryozoan fed yeast or algae were highly variable, ranging from < 1.0 to > 3 000 µl · animal–1 · h–1. 相似文献
3.
The growth of surplus brewers' yeast in a fed-batch process was studied with the aim of increasing the fermentation activity of the yeast cells and of optimizing the growth conditions: 20 h cultivation at 30° C and pH 5.0–5.5 using beet molasses as substrate, with a regulated feeding rate, showed satisfactory results. Under the chosen conditions, the final amount of biomass increased more than fivefold, achieving a specific growth rate of 0.1 h–1 and substrate yield coefficient of 0.54 g·g–1. The increase in fermentation activity of yeast cells during cultivation correlated very well with the concentration of reduced glutathione, which increased from 1.2 to 2.7 mg·g–1 (dry matter). At the same time the fermentation activity increased fivefold, which related to the nitrogen content of the yeast cells. Ethanol formation throughout the cultivation did not exceed 0.5 g·l–1.
Correspondence to: B. Strel 相似文献
4.
Zdeněk Lojda 《Histochemistry and cell biology》1970,22(4):347-361
Summary In the histochemical detection of -D-glucosidase the indigogenic method of Pearson et al. was tested and evaluated. 4-Cl-5-Br-3-indolyl--D-glucoside was used as the substrate.Intestinal -D-glucosidase is firmly bound to the structure. About 60% of activity survives 2 hours fixation in cold 4% formaldehyde and some activity can be demonstrated even in paraffin sections after a shortened embedding.The localization obtained with the original method is not correct. Due to a slow oxidation of indoxyl in the acid pH range and to hydrogen peroxide formation indigo is deposited in sites with an active peroxidase or pseudoperoxidase. The addition of horse-radish peroxidase improves the localization but does not entirely prevent diffusion artifacts. A striking improvement of the localization can be achieved by a mixture of ferri-ferrocyanide. 3.1 · 10–3 M concentration of this oxidation catalyst which is still very effective causes only a 26% inhibition of the enzyme activity as revealed by biochemical assays in homogenates of rat intestine.A new medium was devised consisting of 0.1 M citrate phosphate buffer pH 5.5, 8 · 10–4 M 4-Cl-5-Br-3-indolyl--D-glucoside and 3.1 · 10–3 M ferri-ferrocyanide mixture. With this medium a very clear brush border localization of the enzyme activity (activities) in enterocytes of the rat and human intestine was demonstrated. This activity is present in differentiated enterocytes covering the villi. The highest activity resides in the jejunum. Enzyme activity is considerably inhibited by galactonolactone (5 · 10–3 M) and gluconolactone (4 · 10–4 M). It is completely inhibited by florizin (5 · 10–3 M). Cellobiose (8 · 10–2 M) caused 65%, lactose (8 · 10–2 M) 48% and glucose (8 · 10–2 M) 35% inhibition (data were obtained by cytospectrophotometry). In patients with celiac sprue the activity is very much decreased. Its restitution after a gluten-free diet proceeds roughly parallel to that of lactase. The relationship of the demonstrated activity (activities) to florizin hydrolase and lactase is discussed.In the kidney the reaction is very weak and is confined to the cells of proximal convoluted tubules (diffuse staining with some enhancement at the luminal surface of the brush border). The method is also very useful for processing zymograms. 相似文献
5.
Karel Melzoch Mojmír Rychtera Nikolay S. Markvichov Věra Pospíchalová Gabriela Basařová Michail N. Manakov 《Applied microbiology and biotechnology》1991,34(4):469-472
Summary A series of continuous fermentations were carried out with a production strain of the yeast Saccharomyces cerevisiae in a membrane bioreactor. A membrane separation module composed of ultrafiltration tubular membranes retained all biomass in a fermentation zone of the bioreactor and allowed continuous removal of fermentation products into a cell-free permeate. In a system with total (100%) cell recycle the impact of fermentation conditions [dilution rate (0.03–0.3 h–1); substrate concentration in the feed (50–300 g·1–1); biomass concentration (depending on the experimental conditions)] was studied on the behaviour of the immobilized cell population and on ethanol formation. Maximum ethanol productivity (15 g·1–1·h–1) was attained at an ethanol concentration of 81 g·1–1. The highest demands of cells for maintenance energy were found at the maximum feed substrate concentration (300 g·1–1) and at very low concentrations of cells in the broth. 相似文献
6.
G. Amin R. De Mot K. Van Dijck H. Verachtert 《Applied microbiology and biotechnology》1985,22(4):237-245
Summary Direct alcoholic fermentation of dextrin or soluble starch with selected amylolytic yeasts was studied in both batch and immobilized cell systems. In batch fermentations, Saccharomyces diastaticus was capable of fermenting high dextrin concentrations much more efficiently than Schwanniomyces castellii. From 200 g·l–1 of dextrin S. diastaticus produced 77 g·l–1 of ethanol (75% conversion efficiency). The conversion efficiency decreased to 59% but a higher final ethanol concentration of 120 g·l–1 was obtained with a medium containing 400 g·l–1 of dextrin. With a mixed culture of S. diastaticus and Schw. castellii 136 g·l–1 of ethanol was produced from 400 g·l–1 of dextrin (67% conversion efficiency). S. diastaticus cells attached well to polyurethane foam cubes and a S. diastaticus immobilized cell reactor produced 69 g·l–1 of ethanol from 200 g·l–1 of dextrin, corresponding to an ethanol productivity of 7.6g·l–1·h–1. The effluent from a two-stage immobilized cell reactor with S. diastaticus and Endomycopsis fibuligera contained 70 g·l–1 and 80 g·l–1 of ethanol using initial dextrin concentrations of 200 and 250 g·l–1 respectively. The corresponding values for ethanol productivity were 12.7 and 9.6 g·l–1·h–1. The productivity of the immobilized cell systems was higher than for the batch systems, but much lower than for glucose fermentation. 相似文献
7.
D. Michel-Savin R. Marchal J. P. Vandecasteele 《Applied microbiology and biotechnology》1990,32(4):387-392
Summary The parameters that control fermentation performance of butyrate production have been studied with a selected strain ofClostridium tyrobutyricum. Fed-batch supply of glucose increased productivity for butyrate. The ratio of butyrate to total acids was strongly influenced by the growth rate of the bacteria, acetate being produced along with butyrate at higher growth rates. In glucose-limited, fed-batch cultures, initially produced acetate was re-utilized, resulting in exclusive production of butyrate. In cultures with non-limiting glucose feeding, the butyrate concentration reached 42.5 g·1–1 with a selectivity of 0.90, a productivity of 0.82 g·–1 per hour and a yield of 0.36 g·g–1 The effects of the mode of supply of glucose on the production of butyrate and acetate are discussed in relation with the energy requirements for cell growth. 相似文献
8.
Eric Giraud Alain Brauman Simon Keleke Bertrand Lelong Maurice Raimbault 《Applied microbiology and biotechnology》1991,36(3):379-383
Summary An amylolytic lactic acid bacterium identified as Lactobacillus plantarum was isolated from cassava roots (Manihot esculenta var. Ngansa) during reting. The amylolytic enzyme synthesized was an extracellular -amylase with an optimum pH of 5.0 and an optimum temperature of 55° C. Cultured on starch, the strain displayed a growth rate of 0.43 h–1, a biomass yield of 0.19 g·g–1 and a lactate yield of 0.81 g·g–1. The growth kinetics were similar on starch and glucose. Sufficient enzyme was synthesized and starch hydrolysis was not a limiting factor for growth. Biosynthesis of the enzyme was observed when the glucose concentration was less than 6.7 g·l–1 and reached up to 4 IU·ml–1 at the end of the fermentation.
Offprint requests to: M. Raimbault 相似文献
9.
Summary Changes in the abundance of the components of the microbial plankton between July 1990 and March 1991 in Crooked Lake, one of the largest and deepest freshwater lakes in Antarctica, are described. Chlorophyll a concentration is low (0.2–0.4g·1–1) and there is no discernable spring increase. The phytoplankton is largely dominated by flagellates. Bacterioplankton exhibits a seasonal pattern of abundance ranging from 1.0 × 108·1–1 in July to 3.25 × 108·1–1 in September. Changes in bacterial abundance probably relate to temperature and grazing by heterotrophic and mixotrophic flagellates. Total flagellated protozoan concentrations ranged between 25–136 × 102·l–1. Autotrophic and heterotrophic flagellate abundances were coupled and peaks in their abundance oscillated with peaks in bacterioplankton concentration. Four species of ciliated protozoa, dominated by oligotrichs, particularly the plastidic Strombidium, inhabit the lake. The plankton is characterised by the presence of floes which act as loci for bacteria, flagellates and amoebae and feeding sites for the ciliates and the two sparce metazoan components of the plankton. Crooked Lake is extremely oligotrophic but nonetheless supports a plankton community with a low species diversity and simple trophodynamics. 相似文献
10.
The growth of the anaerobic acetogenic bacterium Acetobacterium woodii DSM 1030 was investigated in fructose-limited chemostat cultures. A defined medium was developed which contained fructose, mineral salts, cysteine · HCl and Ca pantothenate (1 mg · 1–1) supplied in a vitamin supplement. Growth at high dilution rates was dependent on the presence of CO2 in the gas phase. The
max was found to be 0.16 h–1 and the fructose maintenance requirement was 0.1 to 0.13 mmol fructose · (g dry wt)–1 · h–1. A growth yield of 61 g dry wt · (mol fructose)–1, corrected for the cell maintenance requirement and for incorporation of fructose carbon into cell biomass, was determined from the fructose consumption. A corresponding growth yield of 69 g dry wt · (mol fructose)–1 was calculated from the acetate production assuming that fructose fermentation was homoacetogenic. A YATP of 12.2 to 13.8 g dry wt · (mol ATP)–1 was calculated from these growth yields using a value of 5 mol ATP · (mol fructose)–1 as an estimate of the amount of ATP synthesised from fructose fermentation. The addition of yeast extract (0.5 g · 1–1) to the medium did not influence the
max or cell yield. After prolonged growth under fructose-limited conditions the requirement of the culture for CO2 in the gas phase was reduced.Abbreviations YE
yeast extract
- IC
inorganic carbon
- D
fermenter dilution rate : h–1
- MX
maintenance requirement for X: mmol X · (g dry wt)–1 · h–1
- X
may be fructose (Fruct), fructose consumed in energy metabolism (Fruct [E]), acetate (Ac)
- ATP
CO2, NH
inf4
sup+
or Pi
- qX
specific rate of utilisation or consumption of X: mmol X · (g dry wt)–1 · h–1
- V
fermenter volume: litre
- rC
· Cell, fermenter cell carbon production: mmol C · h–1
- YX
yield of cells on X: g dry wt · (mol X)–1
- Y
infx
supmax
the yield corrected for cell maintenance: g dry wt · (mol X)–1
- SATP
stoichiometry of ATP synthesis from fructose: mol ATP · (mol frucose)–1
- x
cell concentration: g dry wt · 1–1
-
specific growth rate : h–1
-
max
maximum specific growth rate: h–1 相似文献
11.
Water conservation and protein metabolism in northern elephant seal pups during the postweaning fast
S. H. Adams D. P. Costa 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1993,163(5):367-373
Urine production and N output were monitored in northern elephant seal (Mirounga angustirostris) pups progressing through 10 weeks of a natural postweaning fast. Urine output declind by 84% (to 69±12 ml·day–1) at 10 weeks (P<0.05). Glomerular filtration rate at 10 weeks was 51% of the 67±3 ml serum·min–1 observed during week 1 (P<0.05). Urine N excretion fell by 69% to 1.2±0.17 g·day–1, while urinary concentration increased (P<0.05). Serum urea declined from an initial 11 mmol·1–1 to 5–7 mmol·1–1 by 5 weeks. The fall in urinary N loss (and thus amino acid oxidation) was concomitant with depressed metabolic rate. Therefore, protein contributed little toward meeting energy demands (i.e., <4% of average metabolic rate) throughout fasting. These data indicate that fasting pups improve water conservation and minimize protein catabolism during prolonged natural fasts without an exogenous source of water.Abbreviations AA
amino acid(s)
- AMR
average metabolic rate
- ANOVA
one-way analysis of variance
- BMR
basal metabolic rate
- BUN
blood urea nitrogen
- EP
end product
- EWL
evaporative water loss
- [Gr]s
serum creatinine concentration
- GFR
glomerular filtration rate
- LBM
lean body mass
- LML
Long Marine Laboratory
- MR
metabolic rate
- NEFA
non-esterified fatty acids
- RMR
resting metabolic rate
- TCA
tricarboxylic acid
- U:C
ulinary urea: creatinine concentration ratio 相似文献
12.
Radomíra Vaňková Miroslav Kamínek Josef Eder Tomáš Vaněk 《Journal of Plant Growth Regulation》1987,6(3):147-157
Two strains of cultured tobacco cells (Nicotiana tabacum L. cv. Wisconsin 38) differing in their requirement for exogenous cytokinins (cytokinin-dependent and cytokinin-autonomous) were immobilized on polyphenylenoxide (Sorfix) activated with glutaraldehyde. Columns packed with immobilized cells were continually eluted with diluted Murashige and Skoog's medium lacking or supplemented with synthetic cytokinin (6-benzylaminopurine; BA). Purified samples of column eluates were fractionated by HPLC, andtrans-zeatin (t-Z) andtrans-zeatin riboside (t-ZR) content was estimated by enzyme immunoassay. Both cytokinin-autonomous and cytokinin-dependent tobacco cells produced and excretedt-Z and its riboside, and there were significant quantitative differences between the strains. The steady-state excretion rate oft-Z was 19.8 ng · g–1 dw · h–1 and 4 ng · g–1 dw · h–1, respectively, and that oft-ZR 4 ng · g–1 dw · h–1 and 1 ng · g–1 dw · h–1, respectively. Exposure of cytokinin-dependent cells to BA after 72 h of starving for this synthetic cytokinin caused temporary increase in excretion of both zeatin and its riboside. After the application of 5 M BA for 24 h, the excretion rate oft-ZR reached 5 ng · g–1 dw · h–1 (5-fold increase), and that oft-Z achieved 12 ng · g–1 dw · h–1 (3-fold increase). The elevation oft-Z excretion was delayed about 13 h compared witht-ZR excretion, which started increasing almost immediately after BA application. A pulse of BA in lower concentration (1.5 M for 30 h) provoked lower response. 相似文献
13.
Zusammenfassung Schwach konzentrierte Tanninlösungen (5·10–5 bis 5·10–8 molar) vermochten das Wachstum 10 mm langer Koleoptilabschnitte von 15 Kulturformen vonAvena sativa, Hordeum distichon, Hordeum vulgare, Zea mays, Triticum aestivum undSecale cereale um etwa 6–25% zu fördern. Die mögliche Beteiligung von Gerbstoffen am Streckungswachstum höherer Pflanzen wurde diskutiert.
Summary The growth of 10 mm coleoptile sections of 15 cultivars ofAvena sativa, Hordeum distichon, Hordeum vulgare, Zea mays, Triticum aestivum andSecale cereale was stimulated by dilute tannin-solutions (5·10–5 to 5·10–8 molar) from 6 up to 25%. The possible role of tannins in elongation growth of higher plants was discussed.相似文献
14.
Bernd Blechschmidt Petra Borneleit Hans-Peter Kleber 《Applied microbiology and biotechnology》1991,36(3):364-368
Summary The formation and localization of the -lactamase of Acinetobacter calcoaceticus CCM 5593 is strongly affected by cultivation and induction conditions. Optimal parameters for enzyme yield are cultivation on minimal salts medium with acetate (10 g·1–1) as carbon source and addition of yeast extract (5–10 g·l–1), induction by cefotaxime (50g·ml–1) immediately after inoculation and growth for 24 h at 25° C. The strain forms a basal level of -lactamase constitutively [70 units (U)·g–1]. Nearly all of this was found to be cell-bound. However, -lactamase activity additionally produced after induction (up to 500 U·g–1 wet bacteria) was located in the culture medium (up to 96%). This unusual localization is a special feature of A. calcoaceticus and is not attributed to cell lysis.
Offprint requests to: P. Borneleit 相似文献
15.
A. S. Afschar K. H. Bellgardt C. E. Vaz Rossell A. Czok K. Schaller 《Applied microbiology and biotechnology》1991,34(5):582-585
Summary
Klebsiella oxytoca fermented 199 g·l–1 high test or invert molasses using batch fermentation with substrate shift to produce 95.2–98.6 g 2,3-butanediol·l–1 and 2,4–4.3 g acetoin·l–1 with a diol yield of 96–100% of the theoretical value and a diol productivity of 1.0–1.1 g·l–1·h–1. Fermentation was performed numerous times with molasses in repeated batch culture with cell recovery. Such repeated batch fermentation, in addition to a high product yield, also showed a very high product concentration. For example, 118 g 2,3-butanediol·l–1 and 2.3 g acetoin·l–1 were produced from 280 g·l–1 of high test molasses. The diol productivity in this fermentation amounted to 2.4 g·l–1·h–1 and can undoubtedly be further increased by increasing the cell concentration. Because the Klebsiella cultures ferment 2,3-butanediol at an extremely high rate once the sugar has been consumed, the culture was inhibited completely by the addition of 15 g ethanol·l–1 and switching off aeration.
Offprint requests to: A. S. Afschar 相似文献
16.
João Carlos M. de Carvalho Eugênio Aquarone Sunao Sato Milton L. Brazzach Dante A. Moraes Walter Borzani 《Applied microbiology and biotechnology》1993,38(5):596-598
Fed-batch ethanol fermentation tests of sugar cane blackstrap molasses were carried out at 32° C and ph 4.5–5.0, using pressed yeast as inoculum, and with no air supply. Two values of the fermentor filling-up time were adopted: 5 h and 7 h. The feeding rates obeyed equation F=F0·–K·t, with K equal to 0.0, 0.2, 0.4, 0.6 and 0.8 h–1. The average yeast yields and the average yeast productivities increased up to 33% and 45%, respectively, while the ethanol yield (average=76%; standard deviation=4%) was practically unaffected when K increased from 0 to 0.8 h–1.
Correspondence to: E. Aquarone 相似文献
17.
Summary Some environmental affects on cell aggregation described in the literature are briefly summarized. By means of a biomass recirculation culture (Contact system), using the yeast Torulopsis glabrata, the aggregation behavior of cells in static and in dynamic test systems is described. Sedimentation times required to obtain 50 g · l–1 yeast dry matter in static systems were always higher than in dynamic ones.In addition to, influencing the biomass yield, the specific growth rate of the yeast also affected cell aggregation. The specific growth rate and therefore the aggregation could be regulated by the biomass recirculation rate as well as by the sedimenter volume.Abbreviations fo
Overflow flow rate (l·h–1)
- fR
Recycle flow rate (l·h–1)
- ft0t
Total flow rate through the fermenter (l·h–1)
- g
Gram
- h
Hour
- DR
Fermenter dilution rate due to recycle (h–1)
- DS
Fermeter dilution rate due to substrate (h–1)
- Dtot
Total fermenter dilution rate (h–1)
- l
Liter
-
Specific growth rate (h–1)
- PF
Fermenter productivity (g·l–1·h–1)
- PFS
Overall productivity (g·l–1·h–1)
- RpM
Rates per minute
- RS
Residual sugar content in the effluent with respect to the substrate concentration (%)
- Y
Yield of biomass with respect to sugar concentration (%)
-
Sed 50
Sedimentation time to reach a YDM of 50 g·l–1 (min)
- V
Volume (l)
- VF
Fermenter volume (l)
- VSed
Sedimenter volume (l)
- VVM
Volumes per volume and minute
- XF
YDM in the fermenter (g·l–1)
- XF
YDM in the recycle (g·l–1)
- XS
Yeast dry matter due to substrate concentration (g·l–1)
- YDM
Yeast dry matter (g·l–1) 相似文献
18.
J. M. Laplace J. P. Delgenes R. Moletta J. M. Navarro 《Applied microbiology and biotechnology》1991,36(2):158-162
Summary To investigate simultaneous alcoholic fermentation of glucose and xylose derived from lignocellulosic material by separate or co-culture processes, the effect of oxygen transfer rate (OTR) on the fermentation of 50 g/l xylose by Pichia stipitis NRRL Y 7124 and Candida shehatae ATCC 22984, and the fermentation of 50 g/l glucose by Saccharomyces cerevisiae CBS 1200 and Zymomonas mobilis ATCC 10988 was carried out in batch cultures. The kinetic parameters of the xylose-fermenting yeasts were greatly dependent on the OTR. The optimum OTR values were found to be 3.9 and 1.75 mmol·1–1·h–1 for C. shehatae and P. stipitis, respectively. By contrast the fermentative parameters of S. cerevisiae were poorly affected by the OTR range tested (0.0–3.5 mmol·l–1·h–1) Under these conditions the ethanol yields ranged from 0.41 g·g–1 to 0.45 g·g–1 and the specific ethanol productivity was around 0.70 g·g–1·h–1. Z. mobilis gave the highest fermentative performance under strictly anaerobic conditions (medium continually flushed with nitrogen): under these conditions, the ethanol yield was 0.43 g·g–1 and the average specific ethanol productivity was 2.3 g·g–1·h–1. Process considerations in relation to the effect of OTR on the fermentative performance of the tested strains are discussed.
Offprint requests to: J. P. Delgenes 相似文献
19.
Eain M. Cornford Deborah Young James W. Paxton Shigeyo Hyman Catherine L. Farrell Robert B. Elliott 《Neurochemical research》1993,18(5):591-597
The intracarotid injection method has been utilized to examine blood-brain barrier (BBB) glucose transport in normal mice, and after a 2-day fast. In anesthetized mice, cerebral blood flow (CBF) rates were reduced from 0.86 ml·min–1·gm–1 in control to 0.80 ml·min–1·gm–1 in fasted animals (p>0.05). Brain Uptake Indices were significantly (p<0.05) higher in fasted (plasma glucose =4.7 mM) than control (plasma glucose = 6.5 mM) mice, while plasma glucose was significantly lower. The maximal velocity (Vmax) for glucose transport was 1562±303 nmoles·min–1·g–1, and the half-saturation constant (Km =) 6.67±1.46 mM in normally fed mice. In fasted mice the Vmax was 2053±393 nmoles·min–1·g–1 (p>0.05), and the half-saturation constant (Km =) 7.30±1.60 mM (not significant, P>0.05). A rabbit polyclonal antiserum to a synthetic peptide encoding the 13 C-terminal amino acids of the human erythrocyte glucose transporter (GLUT-1) immunocytochemically confirmed that the mouse brain capillary endothelial glucose transporter is a GLUT-1 transporter, and immunoreactivity was similar in brain endothelia from fed and fasted animals. In conclusion, after a 2-day fast in the mouse, we saw significant reductions in forebrain weight (7%), and plasma glucose levels (27%). Increased brain glucose extraction (25%, p<0.05), and a 22% increase in the unsaturatedpermeability-surface area product (p<0.05) was also observed. 相似文献
20.
Huicai Wang Xinsheng Wang Xiaoqing Zhang Xia Qin Zixia Zhao Zhiying Miao Nan Huang Qiang Chen 《Biosensors & bioelectronics》2009,25(1):142-146
A novel glucose biosensor was developed, based on the immobilization of glucose oxidase (GOD) with cross-linking in the matrix of bovine serum albumin (BSA) on a Pt electrode, which was modified with gold nanoparticles decorated Pb nanowires (GNPs-Pb NWs). Pb nanowires (Pb NWs) were synthesized by an l-cysteine-assisted self-assembly route, and then gold nanoparticles (GNPs) were attached onto the nanowire surface through –SH–Au specific interaction. The morphological characterization of GNPs-Pb NWs was examined by transmission electron microscopy (TEM). Cyclic voltammetry and chronoamperometry were used to study and to optimize the electrochemical performance of the resulting biosensor. The synergistic effect of Pb NWs and GNPs made the biosensor exhibit excellent electrocatalytic activity and good response performance to glucose. The effects of pH and applied potential on the amperometric response of the biosensor have been systemically studied. In pH 7.0, the biosensor showed the sensitivity of 135.5 μA mM−1 cm−2, the detection limit of 2 μM (S/N = 3), and the response time <5 s with a linear range of 5–2200 μM. Furthermore, the biosensor exhibits good reproducibility, long-term stability and relative good anti-interference. 相似文献