Inhibitory effects of interleukin-6 on release of PGI2 by cultured human pulmonary artery smooth muscle cells

We evaluated the effect of interleukin-6 (IL-6) on the production of prostacyclin (PGI₂) by cultured human pulmonary artery smooth muscle cells (HPASMC). Incubation of these cells for up to 48 h with IL-6 led to a dose- and time-dependent decrease in the concentration of PGI₂ in the culture medium. The incubation of HPASMC with 10 μg/ml of lipopolysaccharide (LPS), 200 U/ml of IL-1β or 500 U/ml of TNFα for 24 hr significantly increased the concentration of PGI₂ in the medium. However, the addition of IL-6 to a medium containing LPS, IL-1β, or TNFα significantly inhibited the stimulatory effect of those substances on PGI₂ production. Such inhibition was closely related to the concentration of IL-6. IL-6 may counteract the roles of LPS and of other cytokines on the regulation of pulmonary vascular tension in endotoxin- and cytokine-mediated disorders such as sepsis and the acute respiratory distress syndrome (ARDS).     

Prostaglandin I2 as a potentiator of acute inflammation in rats

Prostaglandin I₂ potentiated the paw swelling induced by carrageenin in rats. Prostaglandin I₂ (0.1 μg) showed similar activity to PGE₁ (0.01 μg). This potentiating property disappeared in 60 minutes and was completely abolished by diphenhydramine (25 mg kg⁻¹, i.p.). In vascular permeability tests, PGI₂ itself (2.5 × 10⁻¹⁰ mol, 88 ng) caused no dye leakage reaction, but PGE₁ (2.5 × 10⁻¹⁰ mol, 88.5 ng) caused a significant dye leakage. This effect of PGE₁ was statistically significant compared with vehicle- or PGI₂-treated group (p<0.05). Prostaglandin I₂ potentiated the increased vascular permeability induced by 5-hydroxytriptamine (2.5 × 10⁻¹⁰ mol), bradykinin (5 × 10⁻¹⁰ mol) and histamine (2 × 10⁻¹⁰ to 2 × 10⁻⁸ mol). The potentiation was the most evidence in the case of histamine.     

Thromboxane A2 stimulates mitogen activated protein kinase and arachidonic acid liberation in rabbit platelets

U46619, a thromboxane A₂ mimetic, caused tyrosine phosphorylation of several proteins in rabbit platelets. Among them, 42 kDa protein was identified as a mitogen-activated protein kinase (MAPK). U46619 activated MAPK in a concentration-dependent manner, measured by incorporation of ³²P to a specific substrate for MAPK. U46619 also liberated [³H)arachidonic acid in a concentration-dependent manner. The U46619-induced MAPK activation and [³H]arachidonic acid liberation were inhibited by SQ29548 and by the removal of external Ca²⁺ ions. This is a first demonstration that TXA₂ activates MAPK accompanied with arachidonic acid liberation in rabbit platelets.     

Sn-S and Ru-Ru bonds cleavage reactions between [Ph3SnS(CH2)3SSnPh3] and Ru3(CO)12: X-ray crystal structures of [Ph3SnS(CH2)3SSnPh3] and trans-[Ru(CO)4(SnPh3)2]

The organotin complex [Ph₃SnS(CH₂)₃SSnPh₃] (1) was synthesized by PdCl₂ catalyzed reaction between Ph₃SnCl and disodium-1,3-propanedithiolate which in turn was prepared from 1,2-propanedithiol and sodium in refluxing THF. Reaction of 1 with Ru₃(CO)₁₂ in refluxing THF affords the mononuclear complex trans-[Ru(CO)₄(SnPh₃)₂] (2) and the dinuclear complex [Ru₂(CO)₆(μ-κ²-SCH₂CH₂CH₂S)] (3) in 20 and 11% yields, respectively, formed by cleavage of Sn-S bond of the ligand and Ru-Ru bonds of the cluster. Treatment of pymSSnPPh₃ (pymS = pyrimidine-2-thiolate) with Ru₃(CO)₁₂ at 55-60 °C also gives 2 in 38% yield. Both 1 and 2 have been characterized by a combination of spectroscopic data and single crystal X-ray diffraction analysis.     

Kinetic studies of the reduction of hexaaquacobalt(III) perchlorate by a cobaloxime, [Co(dmgBF2)2(H2O)2]

The reaction of with Co(dmgBF₂)₂(H₂O)₂ in 1.0 M HClO₄/LiClO₄ was found to be first-order in both reactants and the [H⁺] dependence of the second-order rate constant is given by k_2obs = b/[H⁺], b at 25 °C is 9.23 ± 0.14 × 10² s⁻¹. The [H⁺] dependence at lower temperatures shows some saturation effect that allowed an estimate of the hydrolysis constant for as K_a = 9.5 × 10⁻³ M at 10 and 15 °C. Marcus theory and the known self-exchange rate constant for Co(OH₂)₅OH^2+/+ were used to estimate an electron self-exchange rate constant of k₂₂ = 1.7 × 10⁻⁴ M⁻¹ s⁻¹ for .     

Study on the heterogeneous degradation of chitosan with H2O2 catalyzed by a new supermolecular assembly crystal: [C6H8N2]6H3[PW12O40]·2H2O

A new supermolecular assembly crystal, [C₆H₈N₂]₆H₃[PW₁₂O₄₀]·2H₂O (DMB-PWA), was synthesized with phosphotungstic acid (PWA) and 1,2-diaminobenzene (DMB) under hydrothermal conditions and was characterized by Fourier-transform infrared spectra (FTIR) and single-crystal X-ray diffraction analysis. DMB-PWA could effectively catalyze oxidative degradation of chitosan with H₂O₂ in the heterogeneous phase. The optimum degradation conditions were determined by orthogonal tests as follows: amount of chitosan 1.00 g, 30% (wt %); H₂O₂, 3.0 mL; dosage of catalyst, 0.06 g; reaction temperature, 85 °C; and reaction time, 30 min. The water-soluble chitosan with a viscosity-average molecular weight (M_v) of 4900 was obtained under the optimum degradation conditions and was characterized by FTIR, ultraviolet-visible diffuse reflection spectra (UV-vis DRS), and X-ray powder diffraction analysis.     

橡胶树暹罗炭疽菌Zn2Cys6型转录因子CsGcc1的生物学功能

【背景】暹罗炭疽菌（Colletotrichum siamense）是一种重要的病原真菌,可以引起炭疽病,给全球橡胶产业带来巨大的经济损失。Zn₂Cys₆型转录因子是真菌特有的锌指类转录因子,通常参与调控真菌的生长发育过程。【目的】在暹罗炭疽菌中鉴定了一个与稻瘟病菌Gcc1同源的Zn₂Cys₆型转录因子CsGcc1,并研究其功能。【方法】根据同源重组原理构建CsGCC1的基因敲除突变体,并通过营养生长、H₂O₂敏感性、分生孢子产生及萌发、玻璃纸试验和致病性分析,明确CsGcc1的功能。【结果】CsGcc1编码一个含有646个氨基酸的蛋白,而且含有一个GAL4结构域。CsGCC1基因在培养36 h的菌丝及分生孢子中具有较高的表达量。CsGCC1基因敲除突变株营养生长速率降低且对H₂O₂更加敏感。相较于野生型菌株,突变株的分生孢子产量、萌发率及附着胞形成率均降低。此外,CsGCC1的敲除可以明显降低分生孢子的穿透能力,突变株对橡胶叶片的致病力减弱。【结论】Zn₂Cys₆型转录因子CsGcc1参与调控暹罗炭疽菌的营养生长、氧化应激、分生孢子发育及致病性等过程。     

1-D coordination chains of Cu(hfac)2 and Mn(hfac)2 bridged by phenyl-nitronylnitroxide derivatives

Two alternating 1-D metal-radical linear [L:Cu(hfac)₂]_n and zig-zag [L:Mn(hfac)₂]_n chains (where L = 4-trimethylsilylethynyl-1-(4,4,5,5-tetramethyl-3-oxylimidazoline-1-oxide)benzene) and hfac = hexafluoroacetylacetonate) are described and characterized by X-ray diffraction of their crystals. Bulk magnetic measurements of L:Cu(hfac)₂ indicated a ferromagnetic interaction with J = 6 cm⁻¹ and L:Mn(hfac)₂ yielded ferrimagnetic interactions with J = −95 cm⁻¹. For the latter, a strong increase of their magnetic moment at lowest temperatures was observed only at very low static magnetic field, while for H_dc > 0.05 T saturation effect led to a downward slope after reaching a maximum.     

Transesterification of sunflower oil to biodiesel on ZrO2 supported La2O3 catalyst

ZrO₂ supported La₂O₃ catalyst prepared by impregnation method was examined in the transesterification reaction of sunflower oil with methanol to produce biodiesel. It was found that the catalyst with 21 wt% loaded La₂O₃ and calcined at 600 °C showed the optimum activity. The basic property of the catalyst was studied by CO₂-TPD, and the results showed that the fatty acid methyl ester (FAME) yield was related to their basicity. The catalyst was also characterized by TG–DTA, XRD, FTIR, SEM and TEM, and the mechanism for the formation of basic sites was discussed. It was also found that the crystallite size of support ZrO₂ decreased by loading of La₂O₃, and the model of the solid-state reaction on the surface of La₂O₃/ZrO₂ catalyst was proposed. Besides, the influence of various reaction variables on the conversion was investigated.     

城市规模对大气污染物NO2和PM2.5浓度的影响

随着我国城市的快速发展,城市的区域性大气污染问题日益突出,尤其是大城市和超大城市的污染问题更加严重。那么城市规模的扩大是否必然导致空气污染的加剧?控制城市人口规模是否是防治空气污染的有效手段?这些问题成为空气污染防治中政府、公众和学者广泛关注的焦点。采用2013年冬季全国114个重点城市两种典型大气污染物-NO_2(传统)和PM_(2.5)(新型)-浓度的实时监测数据,首先分析了这两种大气污染物的空间分布特征,进而定量分析城市人口规模和大气污染物浓度的关系。结果显示:(1)仅有21%的城市NO_2浓度达到WHO的城市年均浓度标准(40μg/m~3),全部城市的PM_(2.5)浓度高于WHO年均浓度标准(10μg/m~3);(2)大气污染物的空间分布具有显著的集聚特征和区域性特征,表现为:NO_2呈较为分散的空间分布,而PM_(2.5)的空间分布呈现"北高南低、内陆高沿海低"的特征。NO_2浓度高的区域主要分布在天津、河北东南部和山东中部地区,PM_(2.5)浓度高的区域主要分布于河北西南部和山东西部;(3)常住人口规模同冬季NO_2和PM_(2.5)浓度呈倒"U"型关系;在1000到1200万的城市冬季平均NO_2和PM_(2.5)浓度最高(NO_2:69.28μg/m~3,PM_(2.5):119.58μg/m~3)。(4)总人口低于1200万的城市,冬季NO_2浓度和PM_(2.5)浓度随着城市规模增加而显著升高(NO_2:r=0.44,P0.01;PM_(2.5):r=0.43,P0.01);总人口高于1200万的城市,NO_2浓度同城市规模呈显著负相关关系(r=0.91,P0.05),PM_(2.5)浓度随城市规模增加逐渐降低。(5)常住人口密度在1000人/km~2以下的重点城市,NO_2和PM_(2.5)浓度同城市人口密度呈显著正相关关系(NO_2:r=0.23,P0.05;PM_(2.5):r=0.36,P0.01)。常住人口密度在1000人/km~2以上的城市人口密度同NO_2和PM_(2.5)浓度呈显著负相关关系(NO_2:r=-0.61,P0.05;PM_(2.5):r=0.63,P0.01)。以上研究结果可以为划定不同大气污染物的重点防治区域和制定联合防治行动计划提供理论依据,并为重点城市大气污染治理和城市人口规模控制理论完善提供参考。     

大庆市6种绿化树种对SO2、NO2的消减及滞尘效应

城市森林在吸收、滞留大气污染物,改善城市生态环境方面具有重要意义。以大庆市6种常见绿化树种为研究对象,采用水洗-滤膜法和熏气试验探究不同树种对总悬浮颗粒物(TSP)、大颗粒物(PM_>10)、粗颗粒物(PM_3—10)和细颗粒物(PM_1—3)的滞留规律以及对大气中SO₂、NO₂的消减效果。研究结果表明：(1)不同树种的滞尘能力差异显著(P<0.05),对TSP的滞留量从大到小依次为：油松(3.82±0.40)g/m²>红瑞木(1.45±0.12)g/m²>紫丁香(1.22±0.17)g/m²>梣叶槭(1.21±0.13)g/m²>大叶杨(0.93±0.17)g/m²>旱柳(0.54±0.14)g/m²;(2)树种间对不同颗粒物的滞留量具有显著差异(P<0.05),供试树种对不同粒径颗粒物滞留的质量占比表现...     

Phosphono-platelet activating factor I. synthesis of 1-O-hexadecyl-2-O-acetyl-glyceryl-3-(2-trimethyl ammonium-methyl) phosphonate and its platelet activating potency

The total synthesis of 1-O-alkyl-2-acetyl-3-glyceryl-(2-trimethyl ammoniummethyl) phosphonate, the phosphono analogue of 1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine, is described. The phosphonolipid shows much lower activity than the phospholipid stimulating serotonin release from rabbit platelets.     

Platelet activating factor (PAF) involvement in endotoxin-induced hypotension in rats. Studies with PAF-receptor antagonist kadsurenone

Evidence from three types of experiments indicates that platelet activating factor (PAF)1 is an important mediator of endotoxin-induced hypotension in rats. a) Endotoxin infusion stimulates the time-dependent appearance of PAF in the blood. b) PAF infusion results immediately (less than 30 sec) in hypotension while endotoxin-induced hypotension takes 3-5 min to occur, allowing time for PAF production. c) Infusion of the specific PAF-receptor antagonist kadsurenone (2.2 mumole/kg bolus, 0.9 mumoles/min/kg continuous infusion), which inhibits PAF-induced hypotension by 67%, causes a 67% reversal of endotoxin-elicited hypotension. An additional finding of this study is that rats respond hypotensively to each of a series of low-dose PAF infusions but only to the first low-dose endotoxin infusion. These endotoxin-refractory rats do respond to subsequent PAF infusions.     

Bis(O2S2 macrocycle) complexes of palladium(II)

Two isomeric dibenzo-O₂S₂ macrocycles L¹ and L² have been synthesised and their coordination chemistry towards palladium(II) has been investigated. Two-step approaches via reactions of 1:1-type complexes, [cis-Cl₂LPd] (1a: L = L¹, 1b: L = L²), with different O₂S₂ macrocycle systems (L¹ and L²) have led to the isolation of the following bis(O₂S₂ macrocycle) palladium(II) complexes in the solid state: [Pd(L¹)₂](ClO₄)₂ (2a) and a mixture of [Pd(L¹)₂](ClO₄)₂ (2a) + [Pd(L²)₂](ClO₄)₂ (2b).     

In silico and in vitro characterization of phospholipase A2 isoforms from soybean (Glycine max)

At the present, no secreted phospholipase A₂ (sPLA₂) from soybean (Glycine max) was investigated in detail. In this work we identified five sequences of putative secreted sPLA₂ from soybean after a BLAST search in G. max database. Sequence analysis showed a conserved PA2c domain bearing the Ca²⁺ binding loop and the active site motif. All the five mature proteins contain 12 cysteine residues, which are commonly conserved in plant sPLA₂s. We propose a phylogenetic tree based on sequence alignment of reported plant sPLA₂s including the novel enzymes from G. max. According to PLA₂ superfamily, two of G. max sPLA₂s are grouped as XIA and the rest of sequences as XIB, on the basis of differences found in their molecular weights and deviating sequences especially in the N- and C-terminal regions of the isoenzymes. Furthermore, we report the cloning, expression and purification of one of the putative isoenzyme denoted as GmsPLA₂-XIA-1. We demonstrate that this mature sPLA₂ of 114 residues had PLA₂ activity on Triton:phospholipid mixed micelles and determine the kinetic parameters for this system. We generate a model based on the known crystal structure of sPLA₂ from rice (isoform II), giving first insights into the three-dimensional structure of folded GmsPLA₂-XIA-1. Besides describing the spatial arrangement of highly conserved pair HIS-49/ASP-50 and the Ca⁺² loop domains, we propose the putative amino acids involved in the interfacial recognition surface. Additionally, molecular dynamics simulations indicate that calcium ion, besides its key function in the catalytic cycle, plays an important role in the overall stability of GmsPLA₂-XIA-1 structure.     

Regulation of sperm motility by PIP2(4,5) and actin polymerization

Actin polymerization and development of hyperactivated (HA) motility are two processes that take place during sperm capacitation. In previous studies, we demonstrated that the increase in F-actin during capacitation depends upon inactivation of the actin severing protein, gelsolin, by its binding to phosphatydilinositol-4, 5-bisphosphate (PIP₂). Here, we showed for the first time the involvement of PIP₂/gelsolin in human sperm motility before and during capacitation. Activation of gelsolin by causing its release from PIP₂ inhibited sperm motility, which could be restored by adding PIP₂ to the cells. Reduction of PIP₂ synthesis inhibited actin polymerization and motility, and increasing PIP₂ synthesis enhanced these activities. Furthermore, sperm demonstrating low motility contained low levels of PIP₂ and F-actin. During capacitation there was an increase in PIP₂ and F-actin levels in the sperm head and a decrease in the tail. In sperm with high motility, gelsolin was mainly localized to the sperm head before capacitation, whereas in low motility sperm, most of the gelsolin was localized to the tail before capacitation and translocated to the head during capacitation. We also showed that phosphorylation of gelsolin on tyrosine-438 depends on its binding to PIP₂. Activation of phospholipase C by Ca²⁺-ionophore or by activating the epidermal-growth-factor-receptor inhibits tyrosine phosphorylation of gelsolin. In conclusion, the data indicate that the increase of PIP₂ and/or F-actin in the head during capacitation enhances gelsolin translocation to the head. As a result the decrease of gelsolin in the tail allows keeping high level of F-actin in the tail, which is essential for the development of HA motility.     

C4作物FACE(free-air CO2 enrichment)研究进展

持续迅速上升的大气二氧化碳浓度([CO₂])是全球变暖最大的驱动因子,但其作为光合作用底物直接增加了作物的生产力。相比C₃作物,人们对未来高浓度CO₂情形下C₄作物的响应规律认识较少。与封闭或半封闭气室研究相比,FACE(free-air CO₂ enrichment)试验在空气自由流动的大田条件下对作物表现进行研究,它提供了对未来作物生长环境的真实模拟,因此提供了评估CO₂肥料效应以及揭示植物响应机制的最好机会。作为人类重要的粮食和饲料来源,高粱和玉米是最重要的C₄作物。在简介美国玉米和高粱FACE系统的基础上,综述了FACE情形下高浓度CO₂(模拟本世纪中叶大气CO₂浓度,即550 μmol/mol)对两大作物生理、生长和产量以及土壤特性等方面的影响,同时比较了与气室研究结果的异同点。(1)FACE使干旱条件下两作物光合作用显著增强,但湿润条件下没有影响;FACE条件下高粱出现光合适应现象,而玉米没有;(2)FACE使两作物气孔导度大幅下降,导致叶温升高、蒸腾速率下降、蒸发蒸腾总量减少或没有变化、叶片总水势和水分利用效率增加或没有变化;(3)FACE对两作物物候期和化学组分影响很少;(4)FACE使干旱条件下两作物生长和产量略有增加,但湿润条件下没有影响;(5)FACE使高粱田土壤丛枝状菌根真菌的长度和易提取胶状物质浓度显著增加,导致水稳性土壤团聚体增加;FACE对高粱田N₂O或含氮气体(N₂O+N₂)的排放没有影响;(6)高浓度CO₂对两作物气孔导度的影响FACE试验明显大于气室试验,而对生长和产量的影响呈相反趋势。阐明CO₂与基因型、土壤湿度和大气温度间的互作效应及其机制是下一轮C₄作物FACE研究优先考虑的方向,技术的不断进步已为利用大型FACE系统来研究这些互作效应提供了可能。     

PGE2 and PGF2α release by human peritoneal macrophages in endometriosis

Objective: To test for differences in the amount and activity of peritoneal macrophages present in the peritoneal fluid of women with, and without endometriosis using prostaglandin release by macrophages in culture as a marker.Patients: Women of reproductive age undergoing laparoscopy for infertility or chronic pelvic pain with postoperative diagnosis of endometriosis and women undergoing laparoscopy for sterilization.Methods: Peritoneal fluid was aspirated during laparoscopy, volume was recorded, macrophages were isolated via a Ficoll Paque gradient and kept in primary culture. PGE₂ and PGF_2α release of the cells were measured before and after stimulation with zymosan.Results: Women with endometriosis had significantly more peritoneal macrophages than controls. Peritoneal macrophages of women with endometriosis released significantly more PGE₂ than those of the control group: 8.4 ± 2.0 versus 1.4 ± 0.4 ng/ml/10⁶cells (mean ± SEM, p=0.0005) and PGF_2α : 10 ± 4.3 (endometriosis) versus 1.8 ± 0.4 (control) ng/ml/10⁶cells (mean ± SEM, p = 0.045).Conclusion: There is a significant increase in the amount of prostaglandins released by peritoneal macrophages from women with endometriosis. These prostaglandins might alter uterine and tubal contractility, thereby affecting fertility.     

Interleukin-1 and tumor necrosis factor are not synergistic for human synovial fibroblast PLA2 activation and PGE2 production

Patterns of arachidonic acid release and metabolism were altered in human synovial fibroblasts following exposure to cytokines. Recombinant interleukin-1 induced an approximate 3-fold in crease in [³H]-AA release, a 7-fold increase in PGE₂ production and a 2-fold increase in PLA₂ activity in human synovial fibroblasts. Recombinant tumor necrosis factor induced similar responses, however, the magnitude was less than that mediated by interleukin-1. A combination of the two cytokines had an additive effect on [³H]-AA release and PLA₂ activity while PGE₂ production was similar to that detected using interleukin-1 alone. [³H]-AA, was released in substantial amounts when sodium fluoride was used as a stimulus but PGE₂ was not. These data show that tumor necrosis factor and interleukin-1 can both activate synovial cell PLA₂ and induce generation of PGE₂, but act in an additive rather than a synergistic fashion. Furthermore, the data show that PGE₂ production is not always concordant with [³H]-AA release, suggesting that appropriate enzyme(s) must be activated.     

Antibacterial properties of recombinant human non-pancreatic secretory phospholipase A2

Human non-pancreatic secretory phospholipase A₂ (hnpsPLA₂) is a group IIA phospholipase A₂ which plays an important role in the innate immune response. This enzyme was found to exhibit bactericidal activity toward Gram-positive bacteria, but not Gram-negative ones. Though native hnpsPLA₂ is active over a broad pH range, it is only highly active at alkaline conditions with the optimum activity pH of about 8.5. In order to make it highly active at neutral pH, we have obtained two hnpsPLA₂ mutants, Glu89Lys and Arg100Glu that work better at neutral pH in a previous study. In the present study, we tested the bactericidal effects of the native hnpsPLA₂ and the two mutants. Both native hnpsPLA₂ and the two mutants exhibit bactericidal activity toward Gram-positive bacteria. Furthermore, they can also kill Escherichia coli, a Gram-negative bacterium. The two mutants showed better bactericidal activity for E. coli at neutral pH than the native enzyme, which is consistent with the enzyme activities. As hnpsPLA₂ is highly stable and biocompatible, it may provide a promising therapy for bacteria infection treatment or other bactericidal applications.