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961.
花椒种籽油的含蜡量测定与脱蜡 总被引:7,自引:0,他引:7
花椒种籽油的含蜡量测定与脱蜡是长期困扰花椒种籽油处理的一项关键技术,本研究通过分析混合压榨制备的花椒种籽油,花椒籽种壳油及种仁油的含蜡量,研究了5种脱蜡方法脱除花椒籽油中蜡质的脱蜡效果,确定了脱除花椒籽油中蜡质的有效方法,研究结果表明,花椒籽油的含蜡量在15-20%,左右,而这些蜡质基本上都含在种壳油内一即种壳上,种仁油基本不含蜡质,脱除花椒籽油中蜡质的合理方法应是:(1)含蜡量相对较低的精制粗油可选用表面活性剂法脱蜡;(2)当含蜡量相对较高时,为降低脱蜡过程中油的耗损率可选用分步脱蜡法脱蜡;(3)需进行碱炼的油,可在碱炼过程中将蜡质与游离脂肪酸一半除去。 相似文献
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964.
Wang Meng Feng Zhigang Li Xiaoxi Sun Shulan Lu Li 《Molecular and cellular biochemistry》2021,476(6):2561-2571
Molecular and Cellular Biochemistry - LncRNAs have been proposed to be associated with the tumorigenesis and progression of oral squamous cell carcinoma (OSCC). LncRNA HLA complex group 22 (HCG22)... 相似文献
965.
Wang Ting-Ting Zhu Chen-Ye Zheng Shuang Meng Cai-Cai Wang Tian-Tian Meng Dan-Hua Li Yi-Jun Zhu Hao-Miao Wang Feng-Shan Sheng Ju-Zheng 《Applied microbiology and biotechnology》2018,102(11):4785-4797
Applied Microbiology and Biotechnology - Avibacterium paragallinarum is a Gram-negative bacterium that causes infectious coryza in chicken. It was reported that the capsule polysaccharides... 相似文献
966.
Shu-Qun Liu Yan Tao Zhao-Hui Meng Yun-Xin Fu Ke-Qin Zhang 《Journal of molecular modeling》2011,17(2):289-300
The native serine protease proteinase K binds two calcium cations. It has been reported that Ca2+ removal decreased the enzyme’s thermal stability and to some extent the substrate affinity, but has discrepant effects on
catalytic activity of the enzyme. Molecular dynamics simulations were performed on the Ca2+-bound and Ca2+-free proteases to investigate the mechanism by which the calciums affect the structural stability, molecular motions, and
catalytic activity of proteinase K. Very similar structural properties were observed between these two forms of proteinase
K during simulations; and several long-lived hydrogen bonds and salt bridges common to both forms of proteinase K were found
to be crucial in maintaining the local conformations around these two Ca2+ sites. Although Ca2+ removal enhanced the overall flexibility of proteinase K, the flexibility in a limited number of segments surrounding the
substrate-binding pockets decreased. The largest differences in the equilibrium structures of the two simulations indicate
that, upon the removal of Ca2+, the large concerted motion originating from the Ca1 site can transmit to the substrate-binding regions but not to the catalytic
triad residues. In conjunction with the large overlap of the essential subspaces between the two simulations, these results
not only provide insight into the dynamics of the underlying molecular mechanism responsible for the unchanged enzymatic activity
as well as the decreased thermal stability and substrate affinity of proteinase K upon Ca2+ removal, but also complement the experimentally determined structural and biochemical data. 相似文献
967.
Biological soil crusts (BSCs, or biocrusts) have important positive ecological functions such as erosion control and soil fertility improvement, and they may also have negative effects on soil moisture in some cases. Simultaneous discussions of the two-sided impacts of BSCs are key to the rational use of this resource. This study focused on the contribution of BSCs while combining with specific types of vegetation to erosion reduction and their effects on soil moisture, and it addressed the feasibility of removal or raking disturbance. Twelve plots measuring 4 m × 2 m and six treatments (two plots for each) were established on a 15° slope in a small watershed in the Loess Plateau using BSCs, bare land (as a control, BL), Stipa bungeana Trin. (STBU), Caragana korshinskii Kom. (CAKO), STBU planted with BSCs (STBU+BSCs) and CAKO planted with BSCs (CAKO+BSCs). The runoff, soil loss and soil moisture to a depth of 3 m were measured throughout the rainy season (from June to September) of 2010. The results showed that BSCs significantly reduced runoff by 37.3% and soil loss by 81.0% and increased infiltration by 12.4% in comparison with BL. However, when combined with STBU or CAKO, BSCs only made negligible contributions to erosion control (a runoff reduction of 7.4% and 5.7% and a soil loss reduction of 0.7% and 0.3%). Generally, the soil moisture of the vegetation plots was lower in the upper layer than that of the BL plots, although when accompanied with a higher amount of infiltration, this soil moisture consumption phenomenon was much clearer when combining vegetation with BSCs. Because of the trivial contributions from BSCs to erosion control and the remaining exacerbated consumption of soil water, moderate disturbance by BSCs should be considered in plots with adequate vegetation cover to improve soil moisture levels without a significant erosion increase, which was implied to be necessary and feasible. 相似文献
968.
Yibao Ma Yuanxi Xu Bryan D. Yestrepsky Roderick J. Sorenson Meng Chen Scott D. Larsen Hongmin Sun 《PloS one》2012,7(10)
Staphylococcus aureus is a major human pathogen and one of the more prominent pathogens causing biofilm related infections in clinic. Antibiotic resistance in S. aureus such as methicillin resistance is approaching an epidemic level. Antibiotic resistance is widespread among major human pathogens and poses a serious problem for public health. Conventional antibiotics are either bacteriostatic or bacteriocidal, leading to strong selection for antibiotic resistant pathogens. An alternative approach of inhibiting pathogen virulence without inhibiting bacterial growth may minimize the selection pressure for resistance. In previous studies, we identified a chemical series of low molecular weight compounds capable of inhibiting group A streptococcus virulence following this alternative anti-microbial approach. In the current study, we demonstrated that two analogs of this class of novel anti-virulence compounds also inhibited virulence gene expression of S. aureus and exhibited an inhibitory effect on S. aureus biofilm formation. This class of anti-virulence compounds could be a starting point for development of novel anti-microbial agents against S. aureus. 相似文献
969.
Olfactory cell cultures on ensheathing cell monolayers 总被引:5,自引:0,他引:5
Olfactory neurons dissociated from the olfactory mucosa of 45-week-oldSprague - Dawley rats are plated on either monolayers of ensheathingcells or cortical astrocytes. It is found that the ensheathingcells support a slightly higher percentage of neurite-bearingolfactory neurons than the astrocytes. Scanning electron microscopyshows that some of the cytoplasmic extensions of the ensheathingcells are closely associated with the olfactory axons whileothers appear to ensheath them. Olfactory neurons grown on uncoated,poly-L-lysine or laminin-coated glass coverslips in the presenceof medium conditioned by ensheathing cells fail to grow neurites,suggesting that interaction between membrane molecules, andnot trophic factors, may be required for neurite growth. However,it is unlikely that these membrane molecules are Ll and N-cadherinbecause immunohistochemical staining shows that only a smallproportion of the cultured ensheathing cells express Ll (9%)and N-cadherin (24%). 相似文献
970.
Hua Zhang Ying Gao Zhengwei Dai Tao Meng Shengfen Tu Yong Yan 《Neurochemical research》2011,36(1):49-57
Insulin-like growth factor 1 (IGF-1) stimulates α-secretase processing of amyloid precursor protein (APP) and decreases Aβ
production. Little is known about the relationship between IGF-1 and β-site amyloid precursor protein cleaving enzyme 1 (BACE-1),
the protease essential for the production of β-amyloid peptides (Aβ). Here, we investigated the effect of IGF-1 on BACE-1
in PC12 cells. Quantitative polymerase chain reaction analysis and western blot showed that treatment of cells with IGF-1
significantly decreased the levels of BACE-1 mRNA and protein. Furthermore, IGF-1 increased the phosphorylation of Akt and
ERK1/2. The presence of the phosphatidylinositol 3-kinase (PI3-K) inhibitor LY294002 and the mitogen-activated protein kinase
kinases (MEK) inhibitor PD98059 blocked the effect of IGF-1 on BACE-1. Our data indicated that IGF-1-induced reduction of
BACE-1 might involve the PI3-K/Akt and MAPK/ERK1/2 signaling pathways. 相似文献