环境因子对海南岛野生兰科植物物种组成与分布格局的影响

海南岛是中国兰科植物物种丰富度较高的地区, 了解环境因子对海南岛野生兰科植物物种组成和分布格局的影响, 对于该地区野生兰科植物的保护管理和相关研究具有重要指导意义。基于海南岛野生兰科植物调查分布样方的植被类型、海拔、坡向、坡度、年平均气温、年降水量的数据, 采用典范相关分析探索了环境因子对物种组成的影响, 并计算各个环境因子对物种组成的总效应与净效应, 同时分析了6个环境因子对野生兰科植物分布格局的影响。结果表明, 所选的6个环境因子共解释了海南岛野生兰科植物组成变异的3.7%; 植被类型、海拔、年平均气温、年降水量、坡向、坡度这6个环境因子的总效应与净效应均达显著水平, 但其解释率依次减小。所选的6个环境因子对海南岛野生兰科植物的分布均有影响, 野生兰科植物在海南岛主要分布在中海拔段、5°-35°的坡度范围、阴坡与半阴坡、年平均气温较低且年降水量较高的环境, 并且于原生植被中分布最多。     

Prognostic Impact of Hyaluronan and Its Regulators in Pancreatic Ductal Adenocarcinoma

Background

Although pancreatic ductal adenocarcinoma is characterized by an abundant stroma enriched with hyaluronan (HA), the prognostic impact of HA and its regulators remains unknown.

Methods

Using immunohistochemistry, expression patterns of HA and its regulators, including a synthesizing enzyme (HAS2), and a degrading enzyme (HYAL1) were investigated in patients who received surgical resection. The prognostic significance of these markers and other clinicopathological variables was determined using univariate and multivariate analyses. The HA levels were determined quantitatively by enzyme-linked immunosorbent assay (ELISA).

Results

We found that strong expressions of HA (P=0.008) and HAS2 (P=0.022) were significantly associated with shorter survival time after surgery. By contrast, weak expression of HYAL1 was significantly associated with poor survival (P=0.001). In multivariate analysis, tumor stage (hazard ratio (HR)=2.76, 95% confidence interval (CI): 1.14-6.66 P=0.024), strong HA expression (HR=6.04, 95%CI: 1.42-25.69 P=0.015), and weak HYAL1 expression (HR=3.16, 95%CI: 1.19-8.40 P=0.021) were independent factors predicting poor survival. ELISA revealed higher concentration of HA in pancreatic cancer tissues than in normal pancreatic tissues (P=0.001).

Conclusion

These findings suggest, for the first time, that HA and its regulators may have prognostic impact in patients with pancreatic cancer.     

Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents

The study of electrophysiological properties of cardiac ion channels with the patch-clamp technique and the exploration of cardiac cellular Ca²⁺ handling abnormalities requires isolated cardiomyocytes. In addition, the possibility to investigate myocytes from patients using these techniques is an invaluable requirement to elucidate the molecular basis of cardiac diseases such as atrial fibrillation (AF).¹ Here we describe a method for isolation of human atrial myocytes which are suitable for both patch-clamp studies and simultaneous measurements of intracellular Ca²⁺ concentrations. First, right atrial appendages obtained from patients undergoing open heart surgery are chopped into small tissue chunks ("chunk method") and washed in Ca²⁺-free solution. Then the tissue chunks are digested in collagenase and protease containing solutions with 20 μM Ca²⁺. Thereafter, the isolated myocytes are harvested by filtration and centrifugation of the tissue suspension. Finally, the Ca²⁺ concentration in the cell storage solution is adjusted stepwise to 0.2 mM. We briefly discuss the meaning of Ca²⁺ and Ca²⁺ buffering during the isolation process and also provide representative recordings of action potentials and membrane currents, both together with simultaneous Ca²⁺ transient measurements, performed in these isolated myocytes.     

单头亚菊的组织培养与快速繁殖

以单头亚菊茎段为外植体对其进行组织培养,MS为基本培养基,设置不同激素浓度配比。对实验结果进行观察分析,筛选出合适的配方。启动培养基为Ms＋0．5mg·L-16-BA＋0．01mg·L-1NAA。继代培养基MS＋O．75mg·L-1。6-BA＋0．01mg·L。NAA,可获得较高的增殖率。不定根最适诱导培养基为1／2MS＋O．15mg·L—IBA,生根率达87％以上,组培苗移栽成活率达98％。     

耐镉马克思克鲁维酵母重金属镉吸附特性的研究

菌株YS-K1是从镉污染土壤中筛选获得的一株耐镉马克思克鲁维酵母Kluyveromyces marxianus YS-K1,对其镉吸附特性研究结果表明,该菌对镉具有良好的耐受性和吸附性,即使在镉浓度高达140mg/L的培养基中也能生长,当镉浓度在30mg/L以下时,24h后能吸附溶液中90%以上的镉,且最佳吸附条件为pH6.0,温度30℃。该菌所吸附的镉大部分集中在细胞壁上,占总吸附镉的76%,细胞膜上的占9%,细胞质中的占15%;能量抑制剂2,4-二硝基苯酚(DNP)和二环己基碳二亚胺(DCC),分别能降低菌株15%和22%的镉吸附量。在Kluyveromyces marxianus YS-K1细胞中,锌离子与镉离子有共用的结合位点,锌离子不仅会与镉离子竞争细胞表面的结合位点,减少其对镉的吸附量,而且也会与镉离子竞争进入细胞的通道位点,减少其对镉的积累量,同时能部分恢复镉离子对菌株生长的抑制作用。     

麻疯树苯丙氨酸解氨酶启动子的克隆和表达载体的构建

苯丙氨酸解氨酶（phenylalanine ammonia lyase, PAL）是苯丙烷类代谢途径的关键酶,催化苯丙氨酸转化为肉桂酸,促进黄酮、香豆素等次生代谢物的生成。本文根据已克隆的麻疯树苯丙氨酸解氨酶基因JcPAL的序列设计引物,通过DNA步移技术,克隆出长度为1 334 bp的JcPAL基因起始密码子上游序列。序列分析显示其不仅具备CAAT、TATA盒这些保守元件,而且包含多种胁迫诱导元件,特别是在序列中发现一些苯丙氨酸解氨酶特有的元件。为了鉴定JcPAL基因的启动子元件,分别将长度不同的5′端侧翼区缺失体定向插入载体pBI121中, 取代原有的CaMV35S启动子,构建了4个驱动报告基因GUS的植物表达载体。     

光氧环境对紫色硫细菌YL28去除无机三态氮的影响

【背景】光和氧是制约光合细菌生长代谢进而影响其除氮效果的重要因素。不产氧光合细菌紫色硫细菌——海洋着色菌(Marichromatium gracile) YL28能以亚硝氮为唯一氮源进行光合生长,对高浓度无机三态氮具有良好去除能力。【目的】阐明YL28菌株除氮效率与光氧环境的交互联系,获得其生物除氮的最适光氧条件。【方法】以高浓度无机三态氮共存海水水体为研究体系,在有光/无光条件下考查装样量(表征体系溶氧状态)对YL28菌株生物除氮活性的影响,并通过响应面分析法对装样量、光照强度和光周期3个主要因素进行优化。【结果】光照且氧浓度较低时(80%装样量),YL28具有最佳生长和无机三态氮去除能力;装样量在10%-100%时,菌体生物量(OD_(660))在0.938-2.719之间,当氨氮、亚硝氮和硝氮分别为7.16、5.67和4.83mmol/L时,其去除率分别在71.44%-89.09%、99.22%-99.83%和91.60%-97.33%。黑暗条件下,装样量在20%-100%时,氨氮、亚硝氮和硝氮去除率分别在48.07%-64.27%、73.51%-86.42%和42.57%-46.34%,但菌体生物量(OD_(660)为0.615-0.903)明显降低。通过响应面优化,当装样量、光照强度和光周期分别为80.0%(溶氧量约为0.32 mg/L)、2 800 lx和24L:0D时,细胞生长和氨氮去除活性达到最佳状态,分别比优化前提高了21.28%和14.11%。在实际应用中,选取72%-89%装样量(溶氧量约为0.26-0.63mg/L)、2240-3460lx光照强度和21L:3D-24L:0D光周期,细胞活性可达95%以上。【结论】80%装样量有助于促进菌体光照生长和除氮;在黑暗有氧和无氧环境下,YL28菌株也具有较好除氮活性,这为不产氧光合细菌在生物反应器中高效去除无机三态氮的应用提供了有价值的参考数据。     

Suberoylanilide Hydroxamic Acid Triggers Autophagy by Influencing the mTOR Pathway in the Spinal Dorsal Horn in a Rat Neuropathic Pain Model

Histone acetylation levels can be upregulated by treating cells with histone deacetylase inhibitors (HDACIs), which can induce autophagy. Autophagy flux in the spinal cord of rats following the left fifth lumber spinal nerve ligation (SNL) is involved in the progression of neuropathic pain. Suberoylanilide hydroxamic acid (SAHA), one of the HDACIs can interfere with the epigenetic process of histone acetylation, which has been shown to ease neuropathic pain. Recent research suggest that SAHA can stimulate autophagy via the mammalian target of rapamycin (mTOR) pathway in some types of cancer cells. However, little is known about the role of SAHA and autophagy in neuropathic pain after nerve injury. In the present study, we aim to investigate autophagy flux and the role of the mTOR pathway on spinal cells autophagy activation in neuropathic pain induced by SNL in rats that received SAHA treatment. Autophagy-related proteins and mTOR or its active form were assessed by using western blot, immunohistochemistry, double immunofluorescence staining and transmission electron microscopy (TEM). We found that SAHA decreased the paw mechanical withdrawal threshold (PMWT) of the lower compared with SNL. Autophagy flux was mainly disrupted in the astrocytes and neuronal cells of the spinal cord dorsal horn on postsurgical day 28 and was reversed by daily intrathecal injection of SAHA (n?=?100 nmol/day or n?=?200 nmol/day). SAHA also decreased mTOR and phosphorylated mTOR (p-mTOR) expression, especially p-mTOR expression in astrocytes and neuronal cells of the spinal dorsal horn. These results suggest that SAHA attenuates neuropathic pain and contributes to autophagy flux in astrocytes and neuronal cells of the spinal dorsal horn via the mTOR signaling pathway.

     

镉诱导金属硫蛋白在华溪蟹组织中的表达

采用体外暴露染毒法,研究了不同浓度与时间条件下,镉诱导河南华溪蟹(Sinopotamon henanense)金属硫蛋白(metallothionein,MT)在肝胰腺、肌肉、鳃和卵巢中的表达差异。镉浓度分别为0、14·5mg/L、29mg/L和58mg/L;处理时间依次为1d、3d和5d。利用镉血红蛋白饱和法和火焰原子吸收分光光度法(AAS)测定MT的蛋白含量。结果显示,用不同的染毒浓度和处理时间,镉在组织中诱导产生MT的含量有较大差异,其中肝胰腺MT的诱导量最大,变化规律也最明显;肌肉中也有较大量MT的表达;而鳃和卵巢MT的诱导量均较低。此外,本文分析了镉的浓度与时间梯度对诱导MT表达的影响与毒性效应机制。结论:组织不同,染毒浓度及时间不同,镉诱导MT的表达也不同,具有一定的组织差异性和规律性。     

Selective cytotoxicity of scFv-TNF fusion protein on the tumor cells

A fusion protein of single-chain, Fv-tumor necrosis factor , scFv-TNF, was constructed and expressed in the Pichia pastoris expression system. There was 67-fold less toxicity of the fusion protein when compared with TNF- alone in cells expressing CA125. Furthermore, scFv-TNF was 10-fold more selective in cell killing directed by anti-CA125 scFv in a CA125-positive cell line than the CA125-negative line.