致癌物诱导恶变细胞中线粒体高变区序列分析

目的检测苯并（a）芘代谢产物反式二羟环氧苯并芘（反式-BPDE）及结晶型硫化镍（NiS）诱发永生化人支气管上皮细胞系（16HBE）恶性转化过程中线粒体DNA控制区序列变化。探讨线粒体DNA控制区在环境致癌物苯并（a）芘及硫化镍致癌作用中是否存在靶分子序列。方法 应用银染PCR-单链构向多态性（SSCP）方法及测序方法分析恶变细胞中线粒体DNA高变区的序列变化。结果 经反式-BPDE和NiS诱导恶变的人支气管上皮细胞系线粒体高变区均未发现异常改变。结论 线粒体基因控制区可能并非是化学致癌物诱发肺癌的靶序列。     

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.     

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。     

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.     

Therapeutic potential of new hydrogen sulfide-releasing hybrids

A new class of hydrogen sulfide (H₂S)-donating hybrids combined with pharmacologically active compounds is presented in this article. The pharmacological profiles of some hybrid lead compounds in the areas of inflammation, H₂S-donating diclofenac (ACS 15); cardiovascular, H₂S-donating aspirin (ACS 14); urology, H₂S-donating sildenafil (ACS 6); and neurodegenerative, H₂S-donating latanoprost (ACS 67) for glaucoma treatment and H₂S-donating levodopa (ACS 84) for Parkinson’s disease, are described. The new H₂S-releasing hybrids demonstrate remarkable improvement in activity and tolerability as compared with the related parent compounds, suggesting an active pharmacological role for H₂S. Finally the mechanism(s) of action of glutathione-dependent and independent, and of gas (H₂S) release (spontaneous or enzymatic) and its implications for clinical pharmacology perspectives will be also discussed.     

Hazards after the storm: Floodwater drainage pump stations and exposure to hydrogen sulfide

A hurricane can present unique hazards that exist long after the strong winds and heavy rains have subsided. These hazards may not only be physical, but chemical as well. Hydrogen sulfide (H₂S) represents an important and potentially overlooked hazard that can be naturally produced in floodwaters following a hurricane. In August of 2012, in the wake of Hurricane Isaac, Plaquemines Parish, Louisiana was submerged under a blanket of floodwater. To remove floodwaters that had breached the levee system designed to keep water out, temporary drainage pump stations were installed at strategic locations. The transfer of floodwaters at these drainage stations resulted in the generation of elevated concentrations of airborne H₂S at the pumping stations. The generation of H₂S at these pumping stations represented a potential inhalation hazard for workers; thus, awareness for possible H₂S exposure at these installments is crucial.     

Malodorous volatile organic sulfur compounds: Sources,sinks and significance in inland waters

Volatile Organic Sulfur Compounds (VOSCs) are instrumental in global S-cycling and greenhouse gas production. VOSCs occur across a diversity of inland waters, and with widespread eutrophication and climate change, are increasingly linked with malodours in organic-rich waterbodies and drinking-water supplies. Compared with marine systems, the role of VOSCs in biogeochemical processes is far less well characterized for inland waters, and often involves different physicochemical and biological processes. This review provides an updated synthesis of VOSCs in inland waters, focusing on compounds known to cause malodours. We examine the major limnological and biochemical processes involved in the formation and degradation of alkylthiols, dialkylsulfides, dialkylpolysulfides, and other organosulfur compounds under different oxygen, salinity and mixing regimes, and key phototropic and heterotrophic microbial producers and degraders (bacteria, cyanobacteria, and algae) in these environs. The data show VOSC levels which vary significantly, sometimes far exceeding human odor thresholds, generated by a diversity of biota, biochemical pathways, enzymes and precursors. We also draw attention to major issues in sampling and analytical artifacts which bias and preclude comparisons among studies, and highlight significant knowledge gaps that need addressing with careful, appropriate methods to provide a more robust understanding of the potential effects of continued global development.     

Role of Aggregatibacter actinomycetemcomitans in glutathione catabolism

Introduction:  Our previous studies demonstrated that three enzymes, γ-glutamyltransferase (GGT), cysteinylglycinase (CGase) and cystalysin, are required for the catabolism of glutathione to produce hydrogen sulfide (H₂S) in Treponema denticola . In this study, we examined glutathione catabolism in Aggregatibacter actinomycetemcomitans .
Methods:  The GGT and CGase of A. actinomycetemcomitans were determined by biological methods and GGT was characterized using a molecular biological approach.
Results:  A. actinomycetemcomitans showed GGT and CGase activity, but could not produce H₂S from glutathione. The addition of recombinant T. denticola cystalysin, an l -cysteine desulfhydrase, to whole cells of A. actinomycetemcomitans resulted in the production of H₂S from glutathione. Subsequently, we cloned A. actinomycetemcomitans GGT gene ( ggt ) and overexpressed the 63 kDa GGT protein. The recombinant A. actinomycetemcomitans GGT was purified and identified. The K _cat/ K _m of the recombinant GGT from N -γ- l -glutamyl-4-nitroaniline as substrate was 31/μ m /min. The activity of GGT was optimum at pH 6.9–7.1 and enhanced by thiol-containing compounds.
Conclusion:  The results demonstrated that A. actinomycetemcomitans had GGT and CGase activities and that the GGT was characterized. The possible role of A. actinomycetemcomitans in glutathione metabolism and H₂S production from oral bacteria was discussed.     

硫化氢保护被ATP损伤的PC12细胞

目的:观察硫化氢的供体硫氢化钠(Na HS)对三磷酸腺苷(ATP)诱导的PC12细胞活力、胞内Ca2+浓度([Ca2+]i)及膜通透性的变化,探讨硫化氢神经保护作用的嘌呤信号机制。方法:将对数生长期高分化的PC12细胞,随机分为4组,分别为(1)正常对照组:常规培养,不进行ATP处理;(2)ATP组:接种细胞24 h后ATP处理;(3)Na HS+ATP组:Na HS预先孵育30 min后再用ATP处理,并且Na HS始终存在于反应体系中;(4)KN-62(P2X7受体阻断剂)+ATP组:KN-62预先孵育30 min,其余同Na HS+ATP组。MTT检测各组细胞活力,Fura-2/AM荧光染料检测各组[Ca2+]i,检测荧光染料YO-PRO-1的相对荧光单位以反映膜的通透性。结果:(1)0.3mmol/L ATP对细胞活力无影响,但1、3、5、10 mmol/L ATP则呈浓度依赖式明显降低细胞活力,200μmol/L Na HS干预可明显逆转ATP引起的细胞活力下降(P0.05),而800μmol/L Na HS预处理则加剧ATP对PC12细胞的损伤(P0.05)。(2)ATP处理PC12细胞会引起[Ca2+]i迅速升高并且呈浓度依赖性,Na HS预处理能对抗ATP引起的[Ca2+]i升高(P0.05)。(3)随着ATP浓度的增加及作用时间的延长,PC12细胞内YO-PRO-1的荧光强度显著增加,Na HS预处理可明显减少细胞对YO-PRO-1的摄取(P0.05)。结论:硫化氢可保护ATP损伤的PC12细胞,可能与其抑制[Ca2+]i升高和YO-PRO-1荧光增强有关。