硫化氢对肝硬化大鼠肝脏survivin表达的影响

目的:探讨抗凋亡因子存活素(survivin)在硫化氢(hydrogen sulfide,H2S)干扰的肝硬化大鼠肝脏中的表达量,了解H2S在肝硬化过程中可能的作用机制.方法:♀SD大鼠经复合因素法复制肝硬化模型,造模结束后随机分为S组、P组、C组,分别腹腔注射硫氢化钠(sodium hydrogen sulfide,NaSH)56mg/(kgd)、炔丙基甘氨酸(Propargylglycine,PPG)30mg/(kgd)及等量生理盐水,用敏感硫电极法检测肝硬化大鼠门静脉中H2S的量,用免疫组织化学及realtime-PCR检测大鼠肝脏survivin蛋白及mRNA表达.结果:S组、P组与C组相比,门静脉血浆内H2S浓度显著改变(51.19mol/L±8.75mol/L,68.97mol/L±2.69mol/Lvs134.49mol/L±12.25mol/L,P<0.05),肝硬化H2S增加组大鼠survivin蛋白及mRNA表达显著增加(P<0.05),肝硬化大鼠体内H2S与survivin表达有相关性.结论:在大鼠肝硬化模型中,随着体内H2S浓度的变化,survivin蛋白及mRNA表达发生变化,这可能是H2S调节肝硬化作用过程中的机制之一.     

Hydrogen Production by Steam Reforming of Ethanol over Nickel Catalysts Supported on Sol Gel Made Alumina: Influence of Calcination Temperature on Supports

Selecting a proper support in the catalyst system plays an important role in hydrogen production via ethanol steam reforming. In this study, sol gel made alumina supports prepared for nickel (Ni) catalysts were calcined at different temperatures. A series of (Ni/Al_S.G.) catalysts were synthesized by an impregnation procedure. The influence of varying the calcination temperature of the sol gel made supports on catalyst activity was tested in ethanol reforming reaction. The characteristics of the sol gel alumina supports and Ni catalysts were affected by the calcination temperature of the supports. The structure of the sol gel made alumina supports was transformed in the order of γ → (γ + θ) → θ-alumina as the calcination temperature of the supports increased from 600 °C to 1000 °C. Both hydrogen yield and ethanol conversion presented a volcano-shaped behavior with maximum values of 4.3 mol/mol ethanol fed and 99.5%, respectively. The optimum values were exhibited over Ni/Al_S.G800 (Ni catalyst supported on sol gel made alumina calcined at 800 °C). The high performance of the Ni/Al_S.G800 catalyst may be attributed to the strong interaction of Ni species and sol gel made alumina which lead to high nickel dispersion and small particle size.     

Transforming Pt-SnO2 Nanoparticles into Pt-SnO2 Composite Nanoceramics for Room-Temperature Hydrogen-Sensing Applications

Many low-dimensional nanostructured metal oxides (MOXs) with impressive room-temperature gas-sensing characteristics have been synthesized, yet transforming them into relatively robust bulk materials has been quite neglected. Pt-decorated SnO₂ nanoparticles with 0.25–2.5 wt% Pt were prepared, and highly attractive room-temperature hydrogen-sensing characteristics were observed for them all through pressing them into pellets. Some pressed pellets were further sintered over a wide temperature range of 600–1200 °C. Though the room-temperature hydrogen-sensing characteristics were greatly degraded in many samples after sintering, those samples with 0.25 wt% Pt and sintered at 800 °C exhibited impressive room-temperature hydrogen-sensing characteristics comparable to those of their counterparts of as-pressed pellets. The variation of room-temperature hydrogen-sensing characteristics among the samples was explained by the facts that the connectivity between SnO₂ grains increases with increasing sintering temperature, and Pt promotes oxidation of SnO₂ at high temperatures. These results clearly demonstrate that some low-dimensional MOX nanocrystals can be successfully transformed into bulk MOXs with improved robustness and comparable room-temperature gas-sensing characteristics.     

实验性肝硬化大鼠肝组织中CSE和Ki-67的表达及其意义

目的应用正常及制备的肝硬化大鼠模型的肝脏组织观察H2S过载及不足状态下肝细胞的增殖变化。方法雌性SD大鼠48只,随机分为6组(每组8只):NF组(正常对照组)、SF组(正常H2S增加组)、PF组(正常H2S减少组)、HF组(肝硬化对照组)、SHF组(肝硬化H2S增加组),PHF组(肝硬化H2S减少组)。分组比较门静脉压力及门静脉血浆H2S含量,免疫组化法观察CSE及Ki-67的表达,免疫荧光双重染色观察CSE及Ki-67是否在同一细胞表达。结果随着给予H2 S供体及H2 S的抑制剂,HF组H2S含量明显低于NF组(P<0.01),SHF组和SF组中,给予H2S供体均能使H2S含量升高(P<0.01),给予H2S供体使H2S含量进一步升高(P<0.01);HF组CSE表达明显低于NF组(P<0.01),SF组H2S表达较SHF组均减少(P<0.01)。H2S对正常大鼠无明显作用;HF组Ki-67表达明显高于NF组(P<0.01),SF组H2S表达较SHF组增加(P<0.01),Ki-67表达在正常大鼠无明显作用。结论 NaHS作为H2S供体可能具有抑制实验性肝硬化大鼠肝组织内细胞增殖的作用,H2S可能通过抑制星状细胞和肝血管平滑肌细胞从而对肝硬化起到保护作用。     

过氧化氢对PC12细胞plk1基因表达的影响

目的 观察过氧化氢对体外培养的PC12细胞plk1基因表达的影响.方法 采用MTT法观察不同浓度过氧化氢对体外培养的PC12细胞作用6h后,对PC12细胞存活率的影响;Western-blot检测不同浓度过氧化氢作用后,PC12细胞plk1基因蛋白表达水平的变化.结果 与对照组比较,过氧化氢剂量依赖性降低PC12细胞的存活率,增强PC12细胞plk1基因蛋白的表达水平.结论 过氧化氢降低PC12细胞的增殖活力,其机制可能是通过增强Plk1蛋白表达水平来实现.     

内源性硫化氢和基于中医气血理论的血瘀证之间的关系

“Qi” and “blood” are two essential concepts in Chinese medicine (CM). As qi is intangible, the concept of qi is still controversial between CM and Western medicine. However, the endogenous hydrogen sulfide (H₂S) and other gaseous signaling molecules provides a new approach for understanding the essence of qi in CM. Blood stasis syndrome is a common syndrome in CM. According to the CM theory, the incidence of blood stasis syndrome is closely correlated to the reckless movement of qi, as qi and blood are inseparable in regulating physiological functions. In recent years, more and more evidences suggest a close correlation between blood stasis syndrome and microcirculation dysfunction. In this paper, we discuss the relationship between endogenous H₂S and blood stasis syndrome based on qi-blood theory of CM. We found that endogenous H₂S maybe a material basis in concept of qi in CM, while dysfunctional microcirculation is the pathological basis of the blood stasis syndrome. As qi is closely associated with incidence and progression of blood stasis syndrome, endogenous H₂S may play an important role in preventing and treating the blood stasis syndrome by improving the function of microcirculation.     

Identification of a functional dddD-Rh for dimethyl sulfide production in the Antarctic Rhodococcus sp. NJ-530

Dimethylsulfoniopropionate (DMSP) is widespread in the oceans, and its biological metabolite, dimethyl sulfide (DMS), plays an important role in the atmosphere. The Antarctic region has become a hotspot in DMS studies due to the high spatial and temporal variability in DMS(P) concentration, but the level of bacterial DMS production remains unclear. In this study, a bacterium isolated from Antarctic floating ice, Rhodococcus sp. NJ-530, was found to metabolize DMSP into DMS, and the rate of DMS production was measured as 3.96 pmol·mg protein⁻¹·h⁻¹. Rhodococcus sp. NJ-530 had a DddD-Rh enzyme containing two CaiB domains, which belonged to the CoA-transferase III superfamily. However, the DddD-Rh had a molecular weight of 73.21 kDa, which was very different from previously characterized DddD enzymes in sequence and evolution. In vitro assays showed that DddD-Rh was functional in the presence of acetyl-CoA. This was the first functional DddD from Gram-positive Actinobacteria. Moreover, a quantitative real-time polymerase chain reaction revealed that high temperature facilitated the expression of dddD-Rh, and changes of salinity had little effect on it. This study adds new evidence to the bacterial DMS production in the Southern Ocean and provides a basis for investigating the metabolic mechanism of DMSP in extreme environments.     

Catalase-mimetic gold nanoparticles inhibit the antagonistic action of Lactobacillus gasseri toward foodborne enteric pathogens in associative cultures

Gold nanoparticles (AuNPs) have been previously shown to induce gut dysbiosis during colitis in mice, but the underlying mechanism is not clear yet. Here, we evaluated the effects of AuNPs (5?nm diameter, coated with tannic acid, polyvinylpyrrolidone or citrate) on H₂O₂ accumulation and pathogen antagonization by an intestinal strain of Lactobacillus gasseri under aerobic cultural conditions. AuNPs (0.65?μg/mL) reduced over 50% of H₂O₂ accumulation by L. gasseri, and significantly inhibited the antagonistic action of L. gasseri on growth of four foodborne enteric pathogens, i.e. Salmonella enterica serovar Typhimurium, Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus in associative cultures.