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1.
Human mast cells (MCs) contain TG-rich cytoplasmic lipid droplets (LDs) with high arachidonic acid (AA) content. Here, we investigated the functional role of adipose TG lipase (ATGL) in TG hydrolysis and the ensuing release of AA as substrate for eicosanoid generation by activated human primary MCs in culture. Silencing of ATGL in MCs by siRNAs induced the accumulation of neutral lipids in LDs. IgE-dependent activation of MCs triggered the secretion of the two major eicosanoids, prostaglandin D2 (PGD2) and leukotriene C4 (LTC4). The immediate release of PGD2 from the activated MCs was solely dependent on cyclooxygenase (COX) 1, while during the delayed phase of lipid mediator production, the inducible COX-2 also contributed to its release. Importantly, when ATGL-silenced MCs were activated, the secretion of both PGD2 and LTC4 was significantly reduced. Interestingly, the inhibitory effect on the release of LTC4 was even more pronounced in ATGL-silenced MCs than in cytosolic phospholipase A2-silenced MCs. These data show that ATGL hydrolyzes AA-containing TGs present in human MC LDs and define ATGL as a novel regulator of the substrate availability of AA for eicosanoid generation upon MC activation.  相似文献   
2.
孢粉学是解决植物分类中疑难类群物种微形态分化的重要方法,随着分子系统学的发展,结合这两门学科的优势可以更加有效地解决疑难类群的分类学问题。鳞盖蕨属(Microlepia)是一个分类困难的疑难类群,采用孢粉学与分子系统学一一对应的方法,以及居群取样方式,选取280份样本,联合4个叶绿体片段(rbcL、trnL-F、psbA-trnH和rps4),采用最大似然法和贝叶斯法构建该属的系统发生关系,在此基础上对凭证标本中100份材料的孢子进行观察和分析。综合分子系统学和孢粉学的研究结果,得出结论:(1)在形态学研究中广泛被接受的15个物种得到了单系支持,并厘清了分类困难的复合群;(2)发现边缘鳞盖蕨(M. marginata)可能存在隐性种;(3)建议恢复过去归并处理为异名的瑶山鳞盖蕨(M. yaoshanica)、罗浮鳞盖蕨(M. lofoushanensis)、四川鳞盖蕨(M. szechuanica)以及滇西鳞盖蕨(M. subspeluncae);(4)提出鳞盖蕨属可能存在杂交现象;(5)提出鳞盖蕨属完整的属下分类建议。  相似文献   
3.
Palmitic acid (PA) is associated with higher blood concentrations of medium-chain acylcarnitines (MCACs), and we hypothesized that PA may inhibit progression of FA β-oxidation. Using a cross-over design, 17 adults were fed high PA (HPA) and low PA/high oleic acid (HOA) diets, each for 3 weeks. The [1-13C]PA and [13-13C]PA tracers were administered with food in random order with each diet, and we assessed PA oxidation (PA OX) and serum AC concentration to determine whether a higher PA intake promoted incomplete PA OX. Dietary PA was completely oxidized during the HOA diet, but only about 40% was oxidized during the HPA diet. The [13-13C]PA/[1-13C]PA ratio of PA OX had an approximate value of 1.0 for either diet, but the ratio of the serum concentrations of MCACs to long-chain ACs (LCACs) was significantly higher during the HPA diet. Thus, direct measurement of PA OX did not confirm that the HPA diet caused incomplete PA OX, despite the modest, but statistically significant, increase in the ratio of MCACs to LCACs in blood.  相似文献   
4.
Septins are a highly conserved family of GTP‐binding proteins that contribute to many cellular and metabolic functions, including cell polarity, cytokinesis, cell morphogenesis and pathogenesis. In this study, we characterized the septins FaCdc3 and FaCdc12 in the filamentous fungus Fusarium asiaticum. The functions of FaCdc3 and FaCdc12 were evaluated by constructing deletion mutants of FaCdc3 and FaCdc12, designated ΔFaCdc3‐5 and ΔFaCdc12‐71, respectively. The deletion mutants exhibited a reduced rate of mycelial growth, increased aerial hyphae formation, irregularly shaped hyphae, reduced conidiation and a lack of sexual reproduction in wheat kernels. Histochemical analysis revealed that the conidia and hyphae of ΔFaCdc3‐5 and ΔFaCdc12‐71 formed large lipid droplets (LDs). ΔFaCdc3‐5 and ΔFaCdc12‐71 also exhibited increased resistance to agents that induce osmotic stress and damage the cell membrane and cell wall. In addition, the hyphae and conidia of the two mutants formed fewer septa than those of the wild‐type and exhibited aberrant nuclear distribution. Pathogenicity assays showed that ΔFaCdc3‐5 and ΔFaCdc12‐71 exhibited reduced virulence on wheat spikelets, which was indirectly correlated with a reduced level of deoxynivalenol accumulation. All of these defects were restored by genetic complementation of the two mutants with the parental FaCdc3 and FaCdc12. These results indicate that FaCdc3 and FaCdc12 play a critical role in various cellular processes in F. asiaticum.  相似文献   
5.
白透骨消化学成分的研究   总被引:1,自引:0,他引:1  
采用乙醇提取,硅胶柱反复层析的方法,从白透骨消[Glechoma biondiana (Diels) C.Y.Wu et C.Chen]全草的乙酸乙酯部分分离了11个化合物,利用现代波谱技术(MS,1H-NMR,13C-NMR,DEPT)以及与文献对照的方法鉴定了这些化合物的结构,分别为2α-羟基乌苏酸(1)、2α,3α-二羟基乌苏-12-烯-28-酸(2)、乌苏酸(3)、2α,3α,23-三羟基乌苏-12-烯-28-酸(4)、3β,24-二羟基乌苏-12-烯-28-酸(5)、3α-羟基乌苏-12-烯-28-酸(6)、豆甾烷-3,6-二酮(7)、7β-羟基谷甾醇(8)、豆甾醇(9)、β-胡萝卜苷(10)、棕榈酸(11).除化合物(3)和(10)外,其余均为首次从该植物中分离得到.  相似文献   
6.
7.
Chemokines are important mediators of cell migration, and thymus and activation-regulated chemokine (TARC/CCL17) and macrophage-derived chemokine (MDC/CCL22) are well-known typical inflammatory chemokines involved in atopic dermatitis (AD). (+)-Nootkatone is the major component of Cyperus rotundus. (+)-Nootkatone has antiallergic, anti-inflammatory, and antiplatelet activities. The purpose of this study was to investigate the effect of (+)-nootkatone on tumor necrosis factor α (TNF-α)/interferon γ (IFN-γ)-induced expression of Th2 chemokines in HaCaT cells. We found that (+)-nootkatone inhibited the TNF-α/IFN-γ-induced expression of TARC/CCL17 and MDC/CCL22 mRNA in HaCaT cells. It also significantly inhibited TNF-α/IFN-γ-induced activation of nuclear factor kappa B (NF-κB), p38 mitogen-activated protein kinase (MAPK), and protein kinase Cζ (PKCζ). Furthermore, we showed that PKCζ and p38 MAPK contributed to the inhibition of TNF-α/IFN-γ-induced TARC/CCL17 and MDC/CCL22 expression by blocking IκBα degradation in HaCaT cells. Taken together, these results suggest that (+)-nootkatone may suppress TNF-α/IFN-γ-induced TARC/CCL17 and MDC/CCL22 expression in HaCaT cells by inhibiting of PKCζ and p38 MAPK signaling pathways that lead to activation of NF-κB. We propose that (+)-nootkatone may be a useful therapeutic candidate for inflammatory skin diseases such as AD.  相似文献   
8.
The objective of the present study was to explore the site of synthesis of vitellogenin (Vtg) in fresh water edible crab, Oziothelphusa senex senex. Vtg cDNA fragments were isolated from the hepatopancreas of female crabs using RT-PCR method, and the deduced amino acid sequence of O. senex senex showed more than 60% identity with other brachyuran Vtg sequences. RT-PCR analysis showed that Vtg mRNA can be detected only in hepatopancreas of female Oziothelphusa but not in other tissues including eyestalks, Y-organs, mandibular organs, thoracic ganglion, hypodermis and ovary. Antibodies were raised against vitellin purified from the ovary of O. senex senex. Immunoprecipitation analysis revealed the presence of Vtg in the hepatopancreas of vitellogenic stage I females and in the hemolymph, hepatopancreas and ovary extracts from vitellogenic stage II females but absent in hemolymph and hepatopancreas extract of males. These results suggest that Vtg is synthesized only in hepatopancreas but not in the ovaries of O. senex senex. In addition, Vtg synthesized in hepatopancreas is transported to ovary through hemolymph.  相似文献   
9.
The human Z-type α1-antitrypsin variant has a strong tendency to accumulate folding intermediates due to extremely slow protein folding within the endoplasmic reticulum (ER) of hepatocytes. Human α1-antitrypsin has 17 peptidyl-prolyl bonds per molecule; thus, the effect of peptidyl-prolyl isomerases on Z-type α1-antitrypsin protein folding was analyzed in this study. The protein level of Cpr2p, a yeast ER peptidyl-prolyl isomerase, increased more than two-fold in Z-type α1-antitrypsin-expressing yeast cells compared to that in wild-type α1-antitrypsin-expressing cells. When CPR2 was deleted from the yeast genome, the cytotoxicity of Z-type α1-antitrypsin increased significantly. The interaction between Z-type α1-antitrypsin and Cpr2p was confirmed by co-immunoprecipitation. In vitro folding assays showed that Cpr2p facilitated Z-type α1-antitrypsin folding into the native state. Furthermore, Cpr2p overexpression significantly increased the extracellular secretion of Z-type α1-antitrypsin. Our results indicate that ER peptidyl-prolyl isomerases may rescue Z-type α1-antitrypsin molecules from retarded folding and eventually relieve clinical symptoms caused by this pathological α1-antitrypsin.  相似文献   
10.
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