广椭牛齿兰，中国兰科一新记录种

报道了在海南热带雨林国家公园内发现的兰科牛齿兰属中国一新记录种：广椭牛齿兰[Appendicula ovalis(Schltr.) J.J.Sm. ex Mansf.]。该种原分布于马来半岛、苏门答腊岛、爪哇岛、婆罗洲、苏拉威西岛,在形态上与国内记录的4种牛齿兰属植物均有较大差别,如茎中部具分枝、叶广椭圆形、单个花序仅着生1朵花、且唇瓣扭转具粉紫色斑块等特征。对产自海南的该种形态和生境进行了详细描述,并提供高清解剖照片。凭证标本保存于海南大学林学院教学标本馆(HUFB)。     

Intracoronary application of nicorandil regulates the inflammatory response induced by percutaneous coronary intervention

Intracoronary application of nicorandil can effectively reduce the myocardial no‐reflow (MNR) after percutaneous coronary intervention (PCI). We sought to investigate the mechanisms of nicorandil in preventing MNR, besides that of dilating the coronary microvasculature. A total of 60 patients undergoing PCI were enrolled and randomly divided into a nicorandil group and a control group. Before PCI, 2 mg of nicorandil or an equal volume of normal saline was injected into the coronary artery. Blood samples were collected before, 24 hours and 1 week after PCI and inflammatory cytokines were tested. In the control group, the expression of pro‐inflammatory cytokines was significantly increased, while the anti‐inflammatory cytokines were decreased 24 hours after PCI. In contrast, these changes were reversed in the nicorandil group, indicating that nicorandil regulated the inflammatory response induced by PCI. Then, proteomic analysis was performed to further elucidate the potential mechanisms. A total of 53 differentially expressed proteins (DEPs) were found 24 hours after PCI in the control group, and the changes of these relevant genes were reversed in the nicorandil group. These DEPs were significantly enriched in the inflammatory pathways. In conclusion, the intracoronary application of nicorandil before PCI can regulate the inflammatory responses induced by PCI, which might be an important mechanism of nicorandil in preventing MNR.     

重组大肠杆菌表达铜绿假单胞菌溶血性磷脂酶C

[目的]构建产溶血性磷脂酶C (Hemolytic Phospholipase C,PLCH)的重组大肠杆菌(Escherich coli菌株,并初步优化其发酵条件.[方法]首先利用卵黄硼砂平板分离法筛选到一株产磷脂酶C(Phospholipase C,PLC)活性较高的菌株,命名为铜绿假单胞菌(Pseudomonas aeruginosa)41;进一步以P.aeruginosa 41基因组DNA为模板设计引物,PCR扩增获得溶血性磷脂酶C(PLCH)基因,构建重组大肠杆菌表达质粒并转化大肠杆菌E.coli BL21 (DE3);筛选转化子并检测PLC活性和溶血能力,并初步优化其发酵条件.[结果]成功构建了重组大肠杆菌E.coli BL21(DE3) /pET28a-plcH;在硼砂卵黄平板上对重组菌进行PLC活性测定,显示重组菌有明显的磷脂酶C活性;在哥伦比亚血琼脂平板上对重组菌进行溶血性试验,表明PLCH具有较强的溶血活性;初步优化摇瓶发酵条件为:5％转接量,37℃、200 r/min下培养4h添加IPTG至终浓度为0.9 mmol/L,转为25℃、150 r/min诱导培养14 h;优化后重组菌的酶活可达到722.89±0.47 U/mL.[结论]本文成功构建了一株产溶血性磷脂酶C活性较高的重组大肠杆菌菌株,并通过优化发酵条件使其酶活达到了722.89±0.47 U/mL,本实验在国内首次实现了铜绿假单胞菌来源的溶血性磷脂酶C基因在大肠杆菌的胞内表达,该研究为研究磷脂酶C产业化奠定了一定的基础.     

阿魏蘑液体发酵过程菌体形态变化对产漆酶的影响

本文旨在研究阿魏蘑菌体形态与漆酶产量之间的关系。结果显示,玻璃珠的添加可改变发酵过程中菌体形态,漆酶产量在球状菌体条件下高于丝状、絮状菌丝：直径分布在0.2~0.4 mm范围的菌球对漆酶的合成具有明显的促进作用;适合的葡萄糖、玉米粉和麸皮添加量,对直径在0.2~0.4 mm范围的菌球形成具有重要影响。此外,添加惰性载体同样可以控制菌球的直径分布,但对漆酶的合成无促进作用。     

Methyl lucidenate F isolated from the ethanol-soluble-acidic components of <Emphasis Type="Italic">Ganoderma lucidum</Emphasis> is a novel tyrosinase inhibitor

Tyrosinase is a key enzyme in the biosynthesis of melanin, and the use of inhibitors against tyrosinase can prevent hyperpigmentation by inhibiting enzymatic oxidation. However, the current use of tyrosine inhibitors is limited by their low activities and high toxicities. The aim of the present research was to develop novel whitening agents, or tyrosinase-targeted medicine, from a submerged culture of the fungus Ganoderma lucidum. Methyl lucidenate F was isolated from the ethanol-soluble-acidic components (ESACs) of G. lucidum, with the structure of ESACs elucidated via UV, LC-MS, and ¹³C-NMR spectral analysis. The tyrosinase inhibitory activity was measured using catechol as a substrate. Methyl lucidenate F displayed uncompetitive inhibition of the potato tyrosinase activity, for which Lineweaver-Burk plots revealed a maximum reaction rate (V _max) of 0.4367/min, Michaelis constant (K _m) of 6.765 mM and uncompetitive inhibition constant (K _i) of 19.22 μM. Meanwhile, methyl lucidenate F (tetra cyclic triterpenoid) exhibited high tyrosinase inhibitory activity, with an IC₅₀ of 32.23 μM. These results suggest that methyl lucidenate F may serve as a potential candidate for skin-whitening agents.     

Understanding lignin-degrading reactions of ligninolytic enzymes: binding affinity and interactional profile

Previous works have demonstrated that ligninolytic enzymes mediated effective degradation of lignin wastes. The degrading ability greatly relied on the interactions of ligninolytic enzymes with lignin. Ligninolytic enzymes mainly contain laccase (Lac), lignin peroxidase (LiP) and manganese peroxidase (MnP). In the present study, the binding modes of lignin to Lac, LiP and MnP were systematically determined, respectively. Robustness of these modes was further verified by molecular dynamics (MD) simulations. Residues GLU460, PRO346 and SER113 in Lac, residues ARG43, ALA180 and ASP183 in LiP and residues ARG42, HIS173 and ARG177 in MnP were most crucial in binding of lignin, respectively. Interactional analyses showed hydrophobic contacts were most abundant, playing an important role in the determination of substrate specificity. This information is an important contribution to the details of enzyme-catalyzed reactions in the process of lignin biodegradation, which can be used as references for designing enzyme mutants with a better lignin-degrading activity.     

The Survival Benefit of Liver Transplantation for Hepatocellular Carcinoma Patients with Hepatitis B Virus Infection and Cirrhosis

Background

A precise predictive survival model of liver transplantation (LT) with antiviral prophylaxis for hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) and cirrhosis has not been established. The aim of our study was to identify predictors of outcome after LT in these patients based on tumor staging systems, antitumor therapy pre-LT, and antiviral prophylaxis in patients considered to be unfit by Milan or UCSF criteria.

Methods

From 2002 to 2008, 917 LTs with antiviral prophylaxis were performed on patients with HBV-cirrhosis, and 313 had concurrent HCC.

Results

Stratified univariate and multivariate analyses demonstrated that independent predictors for poor survival were tumor size >7.5 cm (P = 0.001), tumor number >1 (P = 0.005), vascular invasion (P = 0.001), pre-LT serum alpha-fetoprotein (AFP) level ≥1000 ng/ml (P = 0.009), and pre-LT aspartate aminotransferase (AST) level ≥120 IU/L (P = 0.044). Pre-LT therapy for HCC was an independent predictor of better survival (P = 0.028). Based on CLIP and TNM tumor staging systems, HCC patients with HBV-cirrhosis who met the following criteria: solitary tumor ≤7.5 cm, or ≤4 multifocal nodules, the largest lesion ≤5 cm and total tumor diameter ≤10 cm, or more nodules with the largest lesion ≤3 cm, and pre-LT serum AFP level <1000 µg/L and AST level <120 IU/L without vascular invasion and lymph node metastasis who were unfit for UCSF, had survival rates of 89% at 5 years. There was a 47% 5-year survival rate for patients with HCC exceeding the revised criteria.

Conclusions

The current criteria for LT based on tumor size, number and levels of AFP and AST may be modestly expanded while still preserving excellent survival after LT. The expanded criteria combined with antiviral prophylaxis and pre-LT adjuvant therapy for HCC may be a rational strategy to prolong survival after LT for HCC patients with HBV-associated cirrhosis.     

Growth kinetics of 1–2 mm and 3–4 mm colonies of Nostoc sphaeroides (Cyanophyta) in outdoor culture

Nostoc sphaeroides Kützing was cultivated in paddlewheel-driven raceway ponds and the growth kinetics of 1-2 mm and 3-4 mm colonies of N. sphaeroides was studied. The biomass productivities in 2.5 m(2) raceway ponds inoculated with 1-2 mm and 3-4 mm colonies were 5.2 and 0.25 g dry wt m(-2) d(-1), respectively. Furthermore, differently sized colonies showed different relative water content, total soluble carbohydrates, chlorophyll a content and density of filaments. This is the first report on mass culture of N. sphaeroides under outdoor conditions.