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91.
Li Y Sagar MB Wassler M Shelat H Geng YJ 《Biochemical and biophysical research communications》2007,357(1):157-161
Over-consumption of ethanol (EtOH) represents a major health problem. This study was to test the cytotoxicity of EtOH in cardiac stem cells or myoblasts, and the potential protective effect of apolipoprotein-J (ApoJ), a stress-responding, chaperone-like protein in high-density lipoprotein, on EtOH-injured cardiac myoblasts. In culture, EtOH-exposed canine fetal myoblasts underwent apoptosis in a concentration- and time-dependent manner. Expression ApoJ by cDNA transfection markedly reduced EtOH-induced apoptosis in the cells. ApoJ expression also restored partially the mitochondrial membrane potential and prevented the release of cytochrome-c from mitochondria into cytoplasma. Thus, ApoJ serves as a cytoprotective protein that protects cardiac stem cells against EtOH cytotoxicity. 相似文献
92.
Hydrogen-bond lengths of nucleic acids are (1) longer in DNA than in RNA, and (2) sequence dependent. The physicochemical
basis for these variations in hydrogen-bond lengths is unknown, however. Here, the notion that hydration plays a significant
role in nucleic acid hydrogen-bond lengths is tested. Watson–Crick N1...N3 hydrogen-bond lengths of several DNA and RNA duplexes
are gauged using imino 1
J
NH measurements, and ethanol is used as a cosolvent to lower water activity. We find that 1
J
NH values of DNA and RNA become less negative with added ethanol, which suggests that mild dehydration reduces hydrogen-bond
lengths even as the overall thermal stabilities of these duplexes decrease. The 1
J
NH of DNA are increased in 8 mol% ethanol to those of RNA in water, which suggests that the greater hydration of DNA plays a
significant role in its longer hydrogen bonds. The data also suggest that ethanol-induced dehydration is greater for the more
hydrated G:C base pairs and thereby results in greater hydrogen-bond shortening than for the less hydrated A:T/U base pairs
of DNA and RNA.
Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users. 相似文献
93.
Summary. Gamma-aminobutyric acid (GABA) is considered to be a multifunctional molecule with various physiological effects throughout
the body. It is also evident that the liver contains GABA and its transporter. However, the functions of GABA in liver have
not been well documented. In this study, the cytoprotective effect of GABA against ethanol-induced hepatotoxicity was evaluated
in primary cultured rat hepatocytes. Addition of ethanol induced decrease of cell viability in a dose-dependent manner. However,
treatment with GABA resulted in a dose-dependent recovery from ethanol (150 mM)-induced cytotoxicity.
GABA reversed the ethanol-induced decrease in intracellular polyamine levels. Furthermore, the addition of polyamines also
reversed the ethanol-induced decrease of cell viability. These results suggest that GABA is protective against the cytotoxicity
of ethanol in isolated rat hepatocytes and this effect may be modulated by the maintenance of intracellular polyamine levels. 相似文献
94.
95.
During bioethanol fermentation process, Saccharomyces cerevisiae cell membrane might provide main protection to tolerate accumulated ethanol, and S. cerevisiae cells might also remodel their membrane compositions or structure to try to adapt to or tolerate the ethanol stress. However, the exact changes and roles of S. cerevisiae cell membrane components during bioethanol fermentation still remains poorly understood. This study was performed to clarify changes and roles of S. cerevisiae cell membrane components during bioethanol fermentation. Both cell diameter and membrane integrity decreased as fermentation time lasting. Moreover, compared with cells at lag phase, cells at exponential and stationary phases had higher contents of ergosterol and oleic acid (C18:1) but lower levels of hexadecanoic (C16:0) and palmitelaidic (C16:1) acids. Contents of most detected phospholipids presented an increase tendency during fermentation process. Increased contents of oleic acid and phospholipids containing unsaturated fatty acids might indicate enhanced cell membrane fluidity. Compared with cells at lag phase, cells at exponential and stationary phases had higher expressions of ACC1 and HFA1. However, OLE1 expression underwent an evident increase at exponential phase but a decrease at following stationary phase. These results indicated that during bioethanol fermentation process, yeast cells remodeled membrane and more changeable cell membrane contributed to acquiring higher ethanol tolerance of S. cerevisiae cells. These results highlighted our knowledge about relationship between the variation of cell membrane structure and compositions and ethanol tolerance, and would contribute to a better understanding of bioethanol fermentation process and construction of industrial ethanologenic strains with higher ethanol tolerance. 相似文献
96.
Kim Y Mosier NS Ladisch MR Pallapolu VR Lee YY Garlock R Balan V Dale BE Donohoe BS Vinzant TB Elander RT Falls M Sierra R Holtzapple MT Shi J Ebrik MA Redmond T Yang B Wyman CE Warner RE 《Bioresource technology》2011,102(24):11089-11096
Feedstock quality of switchgrass for biofuel production depends on many factors such as morphological types, geographic origins, maturity, environmental and cultivation parameters, and storage. We report variability in compositions and enzymatic digestion efficiencies for three cultivars of switchgrass (Alamo, Dacotah and Shawnee), grown and harvested at different locations and seasons. Saccharification yields of switchgrass processed by different pretreatment technologies (AFEX, dilute sulfuric acid, liquid hot water, lime, and soaking in aqueous ammonia) are compared in regards to switchgrass genotypes and harvest seasons. Despite its higher cellulose content per dry mass, Dacotah switchgrass harvested after wintering consistently gave a lower saccharification yield than the other two varieties harvested in the fall. The recalcitrance of upland cultivars and over-wintered switchgrass may require more severe pretreatment conditions. We discuss the key features of different pretreatment technologies and differences in switchgrass cultivars and harvest seasons on hydrolysis performance for the applied pretreatment methods. 相似文献
97.
A K270R mutation of xylose reductase (XR) was constructed by site-direct mutagenesis. Fermentation results of the F106X and F106KR strains, which carried wild type XR and K270R respectively, were compared using different substrate concentrations (from 55 to 220 g/L). After 72 h, F106X produced less ethanol than xylitol, while F106KR produced ethanol at a constant yield of 0.36 g/g for all xylose concentrations. The xylose consumption rate and ethanol productivity increased with increasing xylose concentrations in F106KR strain. In particular, F106KR produced 77.6g/L ethanol from 220 g/L xylose and converted 100 g/L glucose and 100g/L xylose into 89.0 g/L ethanol in 72h, but the corresponding values of F106X strain are 7.5 and 65.8 g/L. The ethanol yield of F106KR from glucose and xylose was 0.42 g/g, which was 82.3% of the theoretical yield. These results suggest that the F106KR strain is an excellent producer of ethanol from xylose. 相似文献
98.
Many analytical procedures have been developed to determine the composition of reaction mixtures during transesterification of vegetable oils with alcohols. However, despite their accuracy, these methods are time consuming and cannot be easily used for on-line monitoring. In this work, a fast analytical method was developed to on-line monitor the transesterification reaction of high oleic sunflower oil with ethanol using Near InfraRed spectroscopy and a multivariate approach. The reactions were monitored through sequential scans of the reaction medium with a probe in a one-liter batch reactor without collecting and preparing samples. To calibrate the NIR analytical method, gas chromatography-flame ionization detection was used as a reference method. The method was validated by studying the kinetics of the EtONa-catalyzed transesterification reaction. Activation energy (51.0 kJ/mol) was also determined by considering a pseudo second order kinetics model. 相似文献
99.
Thermo-mechanical extrusion pretreatment for conversion of soybean hulls to fermentable sugars 总被引:1,自引:0,他引:1
Thermo-mechanical extrusion pretreatment for lignocellulosic biomass was investigated using soybean hulls as the substrate. The enzyme cocktail used to hydrolyze pretreated soybean hulls to fermentable sugars was optimized using response surface methodology (RSM). Structural changes in substrate and sugar yields from thermo-mechanical processing were compared with two traditional pretreatment methods that utilized dilute acid (1% sulfuric acid) and alkali (1% sodium hydroxide). Extrusion processing parameters (barrel temperature, in-barrel moisture, screw speed) and processing aids (starch, ethylene glycol) were studied with respect to reducing sugar and glucose yields. The conditions resulting in the highest cellulose to glucose conversion (95%) were screw speed 350 rpm, maximum barrel temperature 80 °C and in-barrel moisture content 40% wb. Compared with untreated soybean hulls, glucose yield from enzymatic hydrolysis of soybean hulls increased by 69.6%, 128.7% and 132.2%, respectively, when pretreated with dilute acid, alkali and extrusion. 相似文献
100.
Wanying Yao Xiao Wu Jun Zhu Bo Sun Yan Y. Zhang Curtis Miller 《Process Biochemistry》2011,46(10):2054-2058
The aim of the work was to study the properties of the bacterial cellulose membrane (BCM) and the feasibility of using it as a new, environmentally friendly support carrier for yeast cell immobilization. It was observed that the morphology of BCM varied with different cultivation methods and the scanning electron microscopy (SEM) images confirmed that the yeast cells were entrapped in the porous network of BCM obtained from the static culture and stabilized by the cross-linked fibrils. Particularly, the research confirmed the effectiveness of yeast immobilization in BCM reflected by the high yield of alcohol (9.7% v/v, a 21.25% increase of those using free cells) and the high stability. The specific rate of ethanol production by the immobilized cells in BCM was 2.1 g g−1 h−1, 31.3% greater than that of the suspended cells. Results implied that applying BCM as the support carrier had little adverse effects on cell viability and proliferation. Instead, it facilitated the product leakage and nutrients transportation through the porous network. 相似文献