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1.
Jian Chen Zuo-Ming Nie Zheng-Bing Lü Cheng-Gang Zhu Cheng-Zhi Xu Yong-Feng Jin Xiang-Fu Wu Yao-Zhou Zhang 《Applied biochemistry and biotechnology》2007,141(1):149-159
Human granulocyte-macrophage colony-stimulating factor (hGM-CSF) acts on many different kinds of cells, including monocytes,
macrophages, granulocytes, eosinophils, and multipotential stem cells. To explore further explore pharmaceutical action, we
expressed hGM-CSF by the Bombyx mori nucleopolyhedrovirus expression system in silkworm pupae. However, purifying recombinant proteins from silkworm pupae on
a large scale has been a big challenge. To establish purification methods suitable for mass production, we tried two crude
preparation methods: (NH4)2SO4 fractional precipitation and isoelectric precipitation with a combination of gel filtration andion-exchange chromatography.
The isoelectric precipitation method was found to be more efficient. With this method, we eventually obtained approx 11.7
mg of 95% pure product from 1000 g of infected silkworm pupae. The recovery of purified protein was greatly increased, by
approx 40%, compared with the other method. The biologic activity of this protein was determined up to 9.0×106 colony-forming units/mg in the final purified product. 相似文献
2.
Microalgal oil is a potential energy source because it can be easily converted to fatty acid methyl ester or hydrocarbon type
of diesel, and it is produced with relatively higher productivity compared with oil from plants and animals. Heterotrophic
growth of microalgae is superior due to its high final product concentration; however, the cost of the raw materials is unacceptable
if sugar is utilized as the carbon source. The aim of this study is to optimize the lipid accumulation of Chlorella protothecoides by using carbon sources other than glucose in heterotrophic and mixotrophic cultures. Different factors such as different
carbon sources, carbon to nitrogen ratio, initial pH level, salinity, and rotational speed are studied in affecting the cell
growth and the oil accumulation. Our experiments revealed that the heterotrophic and mixotrophic cultures of C. protothecoides grew better than autotrophic cultures. C. protothecoides can grow on glycerol or acetate, as well as on glucose. Several stress factors were confirmed or discovered to significantly
increase the lipid content of microalgae cells. The replacement of glycerol and acetate as carbon sources for microalgae cultivations
provides potential for waste utilization: glycerol from biodiesel industry and acetate from biohydrogen production. 相似文献
3.
Hou Shuguo Zhang Wei Zhang Chao Wu Daoji 《Applied biochemistry and biotechnology》2012,166(5):1368-1379
Ax21 (activator of Xa21-mediated immunity), a pathogen-associated molecular pattern secreted by Xanthomonas oryzae pv. oryzae, can be perceived by a membrane-located pattern recognition receptor Xa21 and triggered immune responses in rice. An Ax21-derived
peptide (17-amino acid) containing a sulfated tyrosine-22 (axYS22) is sufficient for Ax21 activity. Here, we expressed Ax21 and O-sulfated its tyrosine-22 through coexpressing a putative
tyrosine sulfotransferase, raxST, and two other genes involved in the synthesis of 3′-phosphoadenosine 5′-phosphosulfate in Escherichia coli BL21 (DE3). The sulfated Ax21 fused with a histidine tag in its N-terminus was extracted and bound onto a Ni-NTA agarose
and then cleaved with Factor Xa and CNBr in turn. Δax21YS22, a 36-amino acid peptide covering axYS22 in the lysate supernatant, was finally yielded after ultrafiltration. The purified peptide was further verified by Tricine-SDS-PAGE
and isoelectrofocusing electrophoresis. Lesion length analysis, reactive oxygen species production, and mitogen-activated
protein kinase (MAPK) activation of rice leaves inoculated with Δax21YS22 confirmed the activity of the sulfated peptide. Overall, this study successfully established an efficient system for expression
and purification of a sulfated peptide. In addition, the sulfotransferase activity of RaxST was confirmed for the first time. 相似文献
4.
Eleonora Winkelhausen Elena Velickova Samuel A. Amartey Slobodanka Kuzmanova 《Applied biochemistry and biotechnology》2010,162(8):2214-2220
A new lyophilization technique was used for immobilization of Saccharomyces cerevisiae cells in hydroxyethylcellulose (HEC) gels. The suitability of the lyophilized HEC gels to serve as immobilization matrices
for the yeast cells was assessed by calculating the immobilization efficiency and the cell retention in three consecutive
batches, each in duration of 72 h. Throughout the repeated batch fermentation, the immobilization efficiency was almost constant
with an average value of 0.92 (12–216 h). The maximum value of cell retention was 0.24 g immobilized cells/g gel. Both parameters
indicated that lyophilized gels are stable and capable of retaining the immobilized yeast cells. Showing the yeast cells propagation
within the polymeric matrix, the scanning electron microscope images also confirmed that the lyophilization technique for
immobilization of S. cerevisiae cells in the HEC gels was successful. The activity of the immobilized yeast cells was demonstrated by their capacity to convert
glucose to ethanol. Ethanol yield of 0.40, 0.43 and 0.30 g ethanol/g glucose corresponding to 79%, 84% and 60% of the theoretical
yield was attained in the first, second and third batches, respectively. The cell leakage was less than 10% of the average
concentration of the immobilized cells. 相似文献
5.
Lei Sun Wenjing Sun Daming Wang Fengjie Cui Xianghui Qi Zhenghong Xu 《Applied biochemistry and biotechnology》2018,185(4):947-957
2-Keto-d-gluconic acid (2KGA) is mainly used for industrial production of erythorbic acid, a food antioxidant. In this study, a 2KGA producing strain JUIM02 was firstly identified as Arthrobacter globiformis by morphological observation and 16S rDNA sequencing. The 2KGA synthetic capacity of A. globiformis JUIM02 was evaluated by both fermentation and bioconversion, with 180 g/L dextrose monohydrate as substrates, in shake flasks and 5 L fermenters. For fermentation, 2KGA titer, yield, molar yield, and productivity of JUIM02 reached 159.05 g/L, 0.97 g/g, 90.18%, and 6.63 g/L/h in 24 h. For non-sterile and buffer-free bioconversion by free resting cells (~?3.2 g/L dry cell weight) of JUIM02, these data were 172.96 g/L, 1.06 g/g, 98.07%, and 5.41 g/L/h in 32 h. Moreover, JUIM02 resting cells could be repeatedly used. Resting cells stored at 4 °C within 30 days showed stable bioconversion capacity, with 2KGA titers ≥?171.50 g/L, yields ≥?1.04 g/g, and molar yields ≥?97.24%. The 2KGA synthetic pathway in A. globiformis, which was rarely reported, was also speculated similar to Pseudomonas and verified preliminarily. In conclusion, A. globiformis JUIM02 is a promising 2KGA industrial-producing strain suitable for various production methods and a suitable object for 2KGA metabolism research of A. globiformis. 相似文献
6.
Michał Adamczyk Janusz Lasek Agnieszka Skawińska 《Applied biochemistry and biotechnology》2016,179(7):1248-1261
CO2 biofixation was investigated using tubular bioreactors (15 and 1.5 l) either in the presence of green algae Chlorella vulgaris or Nannochloropsis gaditana. The cultivation was carried out in the following conditions: temperature of 25 °C, inlet-CO2 of 4 and 8 vol%, and artificial light enhancing photosynthesis. Higher biofixation were observed in 8 vol% CO2 concentration for both microalgae cultures than in 4 vol%. Characteristic process parameters such as productivity, CO2 fixation, and kinetic rate coefficient were determined and discussed. Simplified and advanced methods for determination of CO2 fixation were compared. In a simplified method, it is assumed that 1 kg of produced biomass equals 1.88 kg recycled CO2. Advance method is based on empirical results of the present study (formula with carbon content in biomass). It was observed that application of the simplified method can generate large errors, especially if the biomass contains a relatively low amount of carbon. N. gaditana is the recommended species for CO2 removal due to a high biofixation rate—more than 1.7 g/l/day. On day 10 of cultivation, the cell concentration was more than 1.7?×?107 cells/ml. In the case of C. vulgaris, the maximal biofixation rate and cell concentration did not exceed 1.4 g/l/day and 1.3?×?107 cells/ml, respectively. 相似文献
7.
Background
Arylamine N-acetyltransferases (NATs) are important drug- and carcinogen-metabolising enzymes that catalyse the transfer of an acetyl group from a donor, such as acetyl coenzyme A, to an aromatic or heterocyclic amine, hydrazine, hydrazide or N-hydroxylamine acceptor substrate. NATs are found in eukaryotes and prokaryotes, and they may also have an endogenous function in addition to drug metabolism. For example, NAT from Mycobacterium tuberculosis has been proposed to have a role in cell wall lipid biosynthesis, and is therefore of interest as a potential drug target. To date there have been no studies investigating the kinetic mechanism of a bacterial NAT enzyme. 相似文献8.
Xinyu Li Pengpeng Zhang Ning Zhang Xiao Liang Wenya Wang Qipeng Yuan Qiang Li 《Applied biochemistry and biotechnology》2017,182(4):1433-1443
Narcissus tazetta lectin (NTL) is a GNA-like lectin, which has a wide potential application in medicine, agriculture, and glycobiology. In the present paper, the codon-optimized ntl gene was transformed into the yeast Pichia pastoris; SDS–PAGE gel and western blotting analysis revealed that the recombinant lectin was expressed successfully in Pichia yeast. The similarity between the recombinant NTL and the native NTL was confirmed by circular dichroism (CD) and hemagglutination assay further. In the 5-L scale fermentator, the protein yield was as high as 1.2 g/L after fermentation for 96 h. In addition, the effect of metal ions (K+, Mg2+, Ca2+, and Cu2+), acid, and alkaline on hemagglutinating activity of NTL was tested, which provided biochemical characterizations of the mannose-binding lectin from Chinese Narcissus. 相似文献
9.
Escherichia coli strains expressing the O-glucosyltransferases UGT73B3 or UGT84B1 were compared for the production of glucosides from quercetin supplied into a defined medium. The formation of quercetin-3-glucoside (Q3G) by UGT73B3 showed a maximum at 33 °C, while the formation of quercetin-7-glucoside by UGT84B1 increased with increasing temperature to 37 °C. The highest concentrations of Q3G were attained by strains having a deletion in the pgi gene-coding phosphoglucose isomerase, which effectively blocked the entry of glucose-6P into the Embden–Meyerhof–Parnas pathway. Formation of Q3G was improved in 1-L controlled bioreactors compared to shake flask cultures, a result attributed to the greater oxygen transfer rate in bioreactors. Under batch conditions with 30 g/L glucose as the sole carbon source, E. coli MEC367 (MG1655 pgi) expressing UGT73B3 generated 3.9 g/L Q3G in 56 h. 相似文献
10.
Catechol-O-methyltransferase (COMT) is an enzyme involved in catecholamine catabolism that is key for the treatment of different neurologic disorders. Actually, there are still unmet needs concerning the development of more selective membrane-bound COMT (hMBCOMT) downstream strategies, envisaging their application in structural and bio-interaction studies. Therefore, in this work, recombinant hexahistidine-tagged hMBCOMT (hMBCOMT-His6) was expressed from Pichia pastoris methanol-induced cultures in a catalytically active form (27.3 nmol h?1 mg?1 of protein) and successfully solubilized with n-dodecyl β-d-maltoside. Afterward, immobilized-metal affinity chromatography provided the required selectivity for the direct capture of hMBCOMT-His6 from detergent-solubilized P. pastoris membranes, being the target enzyme recovered in a highly purified fraction. Also, despite the relatively low purification fold (1.53), the purity of the target enzyme assessed by SDS-PAGE is high and it is recovered with biological activity (67 nmol h?1 mg?1 of protein). Then, after a final polishing stage using Q-Sepharose, a pure and immunologically active enzyme fraction was obtained. Overall, the strategy herein reported may be applied to obtain pure hMBCOMT fractions, debottlenecking the implementation of bio-interaction studies and relieving the problems associated with hMBCOMT drug discovery pipeline. In a last analysis, these studies may lead to the establishment of new pharmacological therapies, thereby improving the prognosis of neurologic disorders. 相似文献
11.
Daniel T. Elg Gianluca A. Panici Sumeng Liu Gregory Girolami Shailendra N. Srivastava David N. Ruzic 《Plasma Chemistry and Plasma Processing》2018,38(1):223-245
Extreme ultraviolet (EUV) lithography produces 13.5 nm light by irradiating a droplet of molten Sn with a laser, creating a dense, hot laser-produced plasma and ionizing the Sn to the + 8 through + 12 states. An unwanted by-product is deposition of Sn debris on the collector optic, which focuses the EUV light emitting from the plasma. Consequently, collector reflectivity is degraded. Reflectivity restoration can be accomplished by means of Sn etching by hydrogen radicals, which can be produced by an H2 plasma and etch the Sn as SnH4. It has previously been shown that plasma cleaning can successfully create radicals and restore EUV reflectivity but that the Sn removal rate is not necessarily limited by the radical density. Additionally, while Sn etching by hydrogen radicals has been shown by multiple investigators, quantification of the mechanisms behind Sn removal has never been undertaken. This paper explores the processes behind Sn removal. Experiments and modeling show that, within the parameter space explored, the limiting factor in Sn etching is not radical flux or SnH4 decomposition, but ion energy flux. Thus the removal is akin to reactive ion etching. 相似文献
12.
I. A. Novakov V. V. Korolkov A. I. Pavlyuchko B. S. Orlinson L. A. Gribov 《Journal of Structural Chemistry》2004,45(4):563-569
An ab initio (6-31G**) study of binary associates of aniline and n-propylamine with nitrobenzene and m-cresol has been carried out. The structures corresponding to the total energy minimum of the system have been found for the associates, and their geometrical and energy characteristics have been determined. Basic types of intermolecular interactions have been established, and their effects on the reactivity of the amino group have been investigated.Original Russian Text Copyright © 2004 by I. A. Novakov, V. V. Korolkov, A. I. Pavlyuchko, B. S. Orlinson, and L. A. GribovTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 4, pp. 595–601, July–August, 2004.This revised version was published online in April 2005 with a corrected cover date. 相似文献
13.
M. M. R. Talukder M. M. Zaman Y. Hayashi J. C. Wu T. Kawanishi 《Applied biochemistry and biotechnology》2007,141(1):77-83
The thermostability of Cromobacterium viscosum lip ase (EC 3.1.1.3) entrapped in AOT (sodium bis-[2-ethylhexyl] sulfosuccinate) reverse micelles was in creased by the addition
of short-chain polyethylene glycol (PEG 400). Two different approaches were considered: (1) the determination of half-life
time and (2) the mechanistic analysis of deactivation kinetics. The half-life of lipase entrapped in AOT/isooctane reverse
micelles with PEG 400 at 60°C was 28h, ninefold higher than that in reverse micelles without PEG 400. The lip ase entrapped
in both reverse micellar systems followed a series-type deactivation mechanism involving two first-order steps. The deactivation
constant for the first step at 60°C in PEG containing reverse micelles was 0.055 h11, 11-fold lower than that in reverse micelles without PEG, whereas it remained almost constant for the second step. The inactivation
energy of the lip ase entrapped in reverse micelles with and without PEG 400 was 88.12 and 21.97 kJ/mol, respectively. 相似文献
14.
Strashimir Djoumaliisky Maria Luisa Cerrada Tatyana Dobreva Peter Zipper 《Chemical Papers》2010,64(2):246-254
Structural foam moldings, composed of three co-axial cylinders differing in diameter (10 mm, 20 mm, and 30 mm) and length,
were produced from isotactic polypropylene (PP) and 0.5 mass % 1,1′-azobisformamide on an in-line injection molding machine
in a mould cavity pre-pressurized with nitrogen by the classical low-pressure process combined with egression of foamed melt
from the core. Injection-molding conditions were as follows: melt temperature, 220°C, mold temperature, 20°C, cooling time,
5 min, gas-counter pressure, 0.5 MPa. The sprue gate was at the end of the smallest cylinder and its diameter was varied from
4 mm to 7 mm. To investigate the development of β-PP modification in terms of phenomena due to the phase change in the mould cavity (expansion), appropriate specimens (cross-sections)
were cut from the middle of each cylinder in parallel and perpendicular orientation to the flow direction and were investigated
by WAXS, DSC, and POM. As revealed by WAXS, β-PP is present in all cylinders, always concentrated in certain regions of the cross-section — mainly in the surface layers
of the smallest cylinder (D1) and in the foamed core of the other two cylinders (D2 and D3). Its concentration was found to
change with the sprue dimensions. High β-PP concentration is associated with a preferred orientation in the skin of the smallest cylinder and with better expansion
conditions in larger cylinders. Presence of the β-phase in the surface layers and in the core of the moldings was proved by DSC and POM. 相似文献
15.
Priya Fuke Vaibhav V. Gujar Anshuman A. Khardenavis 《Applied biochemistry and biotechnology》2018,184(3):970-986
Stabilization and utilization of poultry waste demand efficient biodegradation either by mixture of enzymes or by microbial system that can produce different types of protein-hydrolyzing enzymes. For utilization of this keratinous biomass, in the present study, genome was sequenced and annotated for a bacterium having multiple enzymatic options for hydrolysis of different soluble and insoluble protein fractions of poultry waste. Among the soluble protein substrates, optimum production of enzyme and soluble protein was observed in case of casein, whereas among the insoluble protein substrates, maximum production of enzyme was achieved when broken nails were used. Conditions for enhanced enzyme activity with concurrent degradation of keratin-rich poultry feather waste to protein-rich hydrolysate were optimized for different growth parameters. The bacterium grew well and highest protease production occurred in 144 h at mesophilic temperature (30 °C) and alkaline condition (pH 8–10) with enzyme activities of 134 and 168 U/mL, respectively. 相似文献
16.
Daniela Vieira Cortez Solange I. Mussatto Inês Conceição Roberto 《Applied biochemistry and biotechnology》2016,180(5):969-979
Cells of Candida guilliermondii permeabilized with Triton X-100 were able to efficiently produce xylitol from a medium composed only by d-xylose and MgCl2·6H2O in potassium phosphate buffer, at 35 °C and pH 6.5. Under these conditions, the results were similar to those obtained when cofactor and co-substrate or nutrients were added to the medium (about 95 % d-xylose was assimilated producing 42 g/L of xylitol, corresponding to 0.80 g/g yield and 2.65 g/L h volumetric productivity). Furthermore, the permeabilized cells kept the d-xylose assimilation in about 90 % and the xylitol production in approx. 40 g/L during three bioconversion cycles of 16 h each. These values are highly relevant when compared to others reported in the literature using enzyme technology and fermentative process, thereby demonstrating the effectiveness of the proposed method. The present study reveals that the use of permeabilized cells is an interesting alternative to obtain high xylitol productivity using low cost medium formulation. This approach may allow the future development of xylitol production from xylose present in lignocellulosic biomass, with additional potential for implementation in biorefinery strategies. 相似文献
17.
Yong Li 《Theoretical chemistry accounts》2007,117(1):163-165
We present the theoretical results for the positions and widths of the initial anticrossing between Stark manifold n and n + 1 in sodium, obtained by using the method of diagonalization in which zero-field wave functions are chosen from a kind of atomic potential model. These results can provide the quantitative information for understanding the microwave ionization process, whose rate-limiting step is probably the n to n + 1 transition performed at the first crossing between the outermost states of these two manifolds. 相似文献
18.
Xiaofeng Wang Yongchuan Sun Feng Ke Heyun Zhao Tao Liu Li Xu Yun Liu Yunjun Yan 《Applied biochemistry and biotechnology》2012,166(5):1355-1367
A gene encoding Yarrowia lipolytica lipase LIP2 (YlLIP2) was cloned into a constitutive expression vector pGAPZαA and electrotransformed into the Pichia pastoris X-33 strain. The high-yield clones obtained by high copy and enzyme activity screening were chosen as the host strains for
shaking flask and fermentor culture. The results showed that glucose was the optimum carbon source for YlLIP2 production,
and the maximum hydrolytic activity of recombinant YlLIP2 reached 1,315 U/ml under the flask culture at 28 °C, pH 7.0, for
48 h. The fed-batch fermentation was carried out in 3- and 10-l bioreactors by continuously feeding glucose into the growing
medium for achieving high cell density and YlLIP2 yields. The maximum hydrolytic activity of YlLIP2 and cell density obtained
in the 3-l bioreactor were 10,300 U/ml and 116 g dry cell weight (DCW)/l, respectively. The peak hydrolytic activity of YlLIP2
and cell density were further improved in the 10-l fermentor where the values respectively attained were 13,500 U/ml and 120 g
DCW/l. The total protein concentration in the supernatant reached 3.3 g/l and the cell viability remained approximately 99%
after 80 h of culture. Furthermore, the recombinant YlLIP2 produced in P. pastoris pGAP and pAOX1 systems have similar content of sugar (about 12%) and biochemical characteristics. The above results suggest
that the GAP promoter-derived expression system of P. pastoris is effective for the expression of YlLIP2 by high cell density culture and is probably an alternative to the conventional
AOX1 promoter expression system in large-scale production of industrial lipases. 相似文献
19.
Anita Kovács I. Csóka Magdolna Kónya E. Csányi A. Fehér I. Erős 《Journal of Thermal Analysis and Calorimetry》2005,82(2):491-497
Summary The properties of the inner and the external aqueous phases, were studied in w/o/w multiple emulsions with light microscopic image analysis and differential scanning calorimetry (DSC). The importance of multiple
emulsions lies in the presence of these aqueous phases, making them available for sustained, controlled drug delivery systems.
Differentiation of these two aqueous phases, studying the effect of manufacturing technology on droplet structure, quantitative
determination of phase volumes and any changes occurring during storage are essential when planning w/o/w emulsions. The present study uses microscopic observations combined with DSC measurements in order to identify the formed
structure, at developmental stage in case of different components, preparation methods, and stirring rates. These tools are
beneficial during manufacturing as in process controls, or to ensure product quality. 相似文献
20.
Gang-Gang Chong Yu-Cai He Qiu-Xiang Liu Xiao-Qin Kou Qing Qing 《Applied biochemistry and biotechnology》2017,182(4):1341-1357
Effective utilization of winter bamboo shoot shell (BSS) is of great interest, since BSS provides a renewable and inexpensive bioresource for the production of biofuels. In this study, an effective combination pretreatment by the sequential aqueous ammonia (25 wt%) extraction at 50 °C for 24 h and LiCl/N,N-dimethyl formamide (LiCl/DMF) (6 wt% of LiCl) pretreatment at 50 °C for 8 h was used for pretreating BSS. SEM, FTIR, and XRD results indicated that combination pretreatment could effectively remove lignin and change the crystal structure of cellulose for promoting enzymatic saccharification. Additionally, significant linear correlations were found about solid recovery-delignification (R 2 = 0.9235), delignification-reducing sugars (R 2 = 0.9552), and delignification-hemicellulose removal (R 2 = 0.9779) during the combination pretreatment. The reducing sugars and glucose from the hydrolysis of 100 g/L pretreated BSS could be obtained at 72.3 and 40.5 g/L, respectively. Using the recovered BSS-hydrolysates containing 20–50 g/L glucose as carbon source, the ethanol yields at 48 h could be obtained at 84.5–86.1% of the theoretical yield. In conclusion, the sequential ammonia extraction and LiCl/DMF pretreatment has high potential application in future. 相似文献