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21.
Virus inactivation validation studies have been widely applied in the risk assessment of biogenic material-based medical products, such as biological products, animal tissue-derived biomaterials, and allogeneic biomaterials, to decrease the risk of virus transmission. Traditional virus detection methods in an inactivation validation study utilize cell culture as a tool to quantify the infectious virus by observing cytopathic effects (CPEs) after virus inactivation. However, this is susceptible to subjective factors because CPEs must be observed by experts under a microscope during virus titration. In addition, this method is costly and time- and labor-consuming. Molecular biological technologies such as quantitative polymerase chain reaction (qPCR) have been widely used for virus detection but cannot distinguish infectious and noninfectious viruses. Therefore, qPCR cannot be directly applied to virus inactivation validation studies. In this paper, methods to detect viruses and progress in the challenge of differentiating infectious and noninfectious viruses with the combination of pretreatment and qPCR techniques such as the integrated cell culture-qPCR (ICC-qPCR) method are reviewed. In addition, the advantages and disadvantages of each new method, as well as its prospect in virus inactivation validation studies, are discussed. 相似文献
22.
G. Lucchi C. Chambon C. Truntzer D. Pecqueur P. Ducoroy C. Schwartz S. Nicklaus M. Morzel 《International journal of peptide research and therapeutics》2009,15(3):177-185
The objective of the study was to determine optimal conditions for sampling, sample processing and mass-spectrometry based
analysis of infants’ salivary peptidome. Saliva was sampled in 3- and 6-month-old infants and peptide extracts were prepared.
Various sample pretreatments before profiling by MALDI-ToF were evaluated and peptide identification was undertaken by MALDI-ToF/ToF
or nanoLC-ESI-IT tandem MS. A fast and simple protocol (cut-off filtration at 5 kDa) was satisfactory to produce extracts
where no proteolysis was detected even when no protease inhibitor was added. Optimal MALDI spectra were generated after purification
on C18 tips. Variability of spectra between two samples exceeded that of the technical replicates, validating that the method
is suitable to conduct differential studies. Salivary peptides, identified by means of the two complementary mass spectrometry
techniques, were fragments of proline-rich proteins and histatins. The fragments originated mainly from the C-terminal protein
extremities. Indications on the proteolytic systems involved and the anatomic location where they intervene are proposed. 相似文献
23.
24.
盐和水分预处理对扶芳藤幼苗抗寒性的影响 总被引:7,自引:0,他引:7
测定了扶芳藤新品种‘红脉’经不同方式预处理后对幼苗抗寒性的影响,测定了膜脂过氧化水平、保护酶活性和渗透调节物质含量的变化。结果表明,与对照低温胁迫相比,0.1和0.3mol/L NaCl溶液预处理后再经低温胁迫处理,扶芳藤幼苗的膜脂过氧化水平较低、保护酶活性高、渗透调节物质含量的累积较多,不同浓度的NaCl溶液预处理比不同浓度的PEG溶液预处理对提高扶芳藤的抗寒性更有效。通过实验证明了植物在不同的逆境中确实存在着交叉适应现象,植物对各种逆境胁迫有着许多相同的生理反应,对各种胁迫的适应性存在某些共同的机制。 相似文献
25.
A new functionally based kinetic model for enzymatic hydrolysis of pure cellulose by the Trichoderma cellulase system is presented. The model represents the actions of cellobiohydrolases I, cellobiohydrolase II, and endoglucanase I; and incorporates two measurable and physically interpretable substrate parameters: the degree of polymerization (DP) and the fraction of beta-glucosidic bonds accessible to cellulase, F(a) (Zhang and Lynd, 2004). Initial enzyme-limited reaction rates simulated by the model are consistent with several important behaviors reported in the literature, including the effects of substrate characteristics on exoglucanase and endoglucanase activities; the degree of endo/exoglucanase synergy; the endoglucanase partition coefficient on hydrolysis rates; and enzyme loading on relative reaction rates for different substrates. This is the first cellulase kinetic model involving a single set of kinetic parameters that is successfully applied to a variety of cellulosic substrates, and the first that describes more than one behavior associated with enzymatic hydrolysis. The model has potential utility for data accommodation and design of industrial processes, structuring, testing, and extending understanding of cellulase enzyme systems when experimental date are available, and providing guidance for functional design of cellulase systems at a molecular scale. Opportunities to further refine cellulase kinetic models are discussed, including parameters that would benefit from further study. 相似文献
26.
27.
Stream pretreatment of wheat straw solubilized most of the xylan present. Xylose and other sugars were recovered by washing the substrate with water but only a minor part (34%) was monomeric. Treatment of this solutions with celulases and hemicellulases improved the yield of monomeric sugars to 69%, the main product being xylose. Some xylose was also obtained during enzymatic hydrolysis of the solid substrate although the pretreatment step contributed 64% (mean value) of total xylose formed. A reference model, No. 1, and two other models, Nos. 2 and 4, described in the first part of this article series (this issue) have been studied experimentally and results confirm the theoretical conclusions. An uninterrupted hydrolysis over a given time period leads to a lower degree of saccharification than when hydrolysate is withdrawn several times. Saccharification is also favored if the residue is removed at a late stage, i.e., at the end of the 24 h hydrolysis cycle. Extended recirculation of the enzymes during a 4 x 24-h experimental period gave the following average yields of saccharification on a 24-h basis: 65% (Reference), 73% (Model 2), and 79% (Model 4). It is concluded that enzyme recovery with model 4 is 70% or more, while the Reference and Model 2 attain a lower level of recovery. The design of an improved hydrolysis model is also discussed. 相似文献
28.
Myoblast transplantation (MT) is a cell-based gene therapy treatment, representing a potential treat-ment for Duchenne muscular dystrophy (DMD), cardiac failure and muscle trauma. The rapid and mas-sive death of transplanted cells after MT is considered as a major hurdle which limits the efficacy of MT treatment. Heat shock proteins (HSPs) are overexpressed when cells undergo various insults. HSPs have been described to protect cells in vivo and in vitro against diverse insults. The aim of our study is to investigate whether HSP overexpression could increase myoblast survival after autotransplantation in pig intact skeletal muscle. HSP expression was induced by warming the cells at 42℃ for 1 h. HSP70 expression was quantified by Western blot and flow cytometry 24 h after the treatment. To investigate the myogenic characteristics of myoblasts, desmin and CD56 were analysed by Western blot and flow cytometry; and the fusion index was measured. We also quantified cell survival after autologous transplantation in pig intact skeletal muscle and followed cell integration. Results showed that heat shock treatment of myoblasts induced a significative overexpression of the HSP70 (P < 0.01) without loss of their myogenic characteristics as assessed by FACS and fusion index. In vivo (n=7), the myoblast survival rate was not significantly different at 24 h between heat shock treated and non- treated cells (67.69% ± 8.35% versus 58.79% ± 8.35%, P > 0.05). However, the myoblast survival rate in the heat shocked cells increased by twofold at 48 h (53.32% ± 8.22% versus 28.27% ± 6.32%, P < 0.01) and more than threefold at 120 h (26.33% ± 5.54% versus 8.79% ± 2.51%, P < 0.01). Histological analy-sis showed the presence of non-heat shocked and heat shocked donor myoblasts fused with host myoblasts. These results suggested that heat shock pretreatment increased the HSP70 expression in porcine myoblasts, and improved the survival rate after autologous transplantation. Therefore, heat shock pretreatment of myoblast in vitro is a simple and effective way to enhance cell survival after transplantation in pig. It might represent a potential method to overcome the limitations of MT treat-ment. 相似文献
29.
Tingting You Ruizhen Wang Xueming Zhang Shri Ramaswamy Feng Xu 《Biotechnology and bioengineering》2018,115(1):82-91
Ionic liquid (IL)‐acid pretreatment is known to not only enhance the enzymatic hydrolysis efficiency of lignocellulose but also to generate deposits on the surface of fiber by conventional water regeneration, which retard the increment. In this study, ethanol aqueous solution regeneration was developed as a new method to change the substrates characteristics for IL‐acid pretreatment and their effects on the enzymatic hydrolysis were evaluated. Following the IL‐acid reaction, the biomass slurry was subjected to ethanol aqueous solution at various concentration. Results indicated that anti‐solvent choice significantly influenced the reconstruction of both hemicelluloses and lignin as a result of the competition between water and ethanol. The partial removal of hemicelluloses and suitable lignin re‐localization contributed to a more porous structure. Consequently, the cellulose digestibility of aqueous ethanol regenerated samples was dramatically enhanced to ~100% and approximately 11‐ and 2‐fold higher than that of untreated and conventional water regenerated pretreated samples, respectively. A giant leap in the initial rate of enzymatic hydrolysis was also detected in 50% ethanol aqueous solution regenerated samples and only about 10 hr was needed to convert 80% of cellulose to glucose due to the appearance of cellulose II hydrate‐like and more porous structure. 相似文献
30.
Piyush Parkhey Aadil Keshaw Ram Batul Diwan J. Satya Eswari 《Preparative biochemistry & biotechnology》2020,50(8):768-780
AbstractThe present study demonstrates a comparative analysis between the artificial neural network (ANN) and response surface methodology (RSM) as optimization tools for pretreatment and enzymatic hydrolysis of lignocellulosic rice straw. The efficacy for both the processes, that is, pretreatment and enzymatic hydrolysis was evaluated using correlation coefficient (R2) & mean squared error (MSE). The values of R2 obtained by ANN after training, validation, and testing were 1, 0.9005, and 0.997 for pretreatment and 0.962, 0.923, and 0.9941 for enzymatic saccharification, respectively. On the other hand, the R2 values obtained with RSM were 0.9965 for cellulose recovery and 0.9994 for saccharification efficiency. Thus, ANN and RSM together successfully identify the substantial process conditions for rice straw pretreatment and enzymatic saccharification. The percentage of error for ANN and RSM were 0.009 and 0.01 for cellulose recovery and for 0.004 and 0.005 for saccharification efficiency, respectively, which showed the authority of ANN in exemplifying the non-linear behavior of the system. 相似文献