鸢尾切花保鲜的初步研究

本文通过对影响切花保鲜的pH值、切口处理、糖分、细菌数等的实验研究,初步探讨了不同配方保鲜剂对鸢尾切花保鲜的影响。     

N-aroyloxylthioxo-naphthalimides as DNA photocleavers of aroyloxyl oxygen radicals: synthesis, evaluation, and substituents' effect

Novel N-Aroyloxylthioxo-naphthalimides as highly efficient 'time-resolved' DNA photocleavers of aroyloxyl radicals type were designed and synthesized. The substituents at the aroyloxyl moiety have an important and unusual influence on the DNA photocleavage, and DNA photodamages of the compounds were unusually not depended on the electronic effects of substituents on the corresponding oxygen-centered radicals. With AM1 semi-empirical quantum calculation, it was found that their photocleaving activities were correlated with the densities of electron clouds on the N-O bonds in the triplet state. N-(m-Dichloro-benzoyloxy)-thioxo-naphthalimide could photodamage DNA effectively at less than the concentration of 2 microM.     

Essential roles of the Bcl-2 family of proteins in caspase-2-induced apoptosis

Caspase-2 is an initiating caspase required for stress-induced apoptosis in various human cancer cells. Recent studies suggest that it can mediate the death function of tumor suppressor p53 and is activated by a multimeric protein complex, PIDDosome. However, it is not clear how caspase-2 exerts its apoptotic function in cells and whether its enzymatic activity is required for the apoptotic function. In this study, we used both in vitro mitochondrial cytochrome c release assays and cell culture apoptosis analyses to investigate the mechanism by which caspase-2 induces apoptosis. We show that active caspase-2, but neither a catalytically mutated caspase-2 nor active caspase-2 with its inhibitor, can cause cytochrome c release. Caspase-2 failed to induce cytochrome c release from mitochondria with Bid(-/-) background, and the release could be restored by addition of the wild-type Bid protein, but not by Bid with the caspase-2 cleavage site mutated. Caspase-2 was not able to induce cytochrome c release from Bax(-/-)Bak(-/-) mitochondria either. In cultured cells, gene deletion of Bax/Bak or Bid abrogated apoptosis induced by overexpression of caspase-2. Collectively, these results indicate that proteolytic activation of Bid and the subsequent induction of the mitochondrial apoptotic pathway through Bax/Bak is essential for apoptosis triggered by caspase-2.     

A novel synthetic fluoro-containing jasmonate derivative acts as a chemical inducing signal for plant secondary metabolism

A novel fluoro-containing jasmonate derivative was chemically synthesized and evaluated as a potential elicitor with respect to the induction of plant defense responses and the biosynthesis of plant secondary metabolites. A bioactive taxuyunnanine C (Tc)-producing cell line of Taxus chinensis was taken as a model plant cell system. The presence of novel synthesized pentafluoropropyl jasmonate (PFPJA) induced two early and important events in plant defense responses, including an oxidative burst and activation of l-phenylalanine ammonia lyase. In addition, PFPJA was found to significantly increase Tc accumulation, without any inhibition of cell growth. Moreover, Tc accumulation was increased more in the presence of PFPJA compared with methyl jasmonate (MJA) and previously reported trifluoroethyl jasmonate (TFEJA). For example, addition of 100 M PFPJA on day 7 led to a high Tc content (38.2±0.3 mg/g) at day 21, while the Tc content was 29.3±0.3 mg/g and 34.9±0.9 mg/g with the addition of 100 M MJA and TFEJA, respectively. Quantitative structure–activity analysis of fluoro-containing jasmonates suggests that the increase in the fluoro-groups introduced into the carboxyl side-chain of MJA resulted in a higher stimulatory activity for Tc biosynthesis, which corresponds well with the markedly increased lipophilicity after fluorine introduction. These results indicate that newly synthesized fluoro-containing PFPJA can act as a powerful chemical inducing signal for secondary metabolism in plant cell cultures.     

Diagnosis of liver cancer using HPLC-based metabonomics avoiding false-positive result from hepatitis and hepatocirrhosis diseases

Metabonomics, the study of metabolites and their roles in various disease states, is a novel methodology arising from the post-genomics era. This methodology has been applied in many fields. Current metabonomics practice has relied on mass spectrometry (MS), gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) to analyze metabolites. In this study, a novel approach of using high-performance liquid chromatography (HPLC) in conjunction with developed software was employed. Using the principal components analysis method (PCA), all (113) peaks of urinary metabolites with a cis-diol structure from patients with hepatitis and hepatocirrhosis were compared to those from liver cancer patients. The results showed that the metabonomics-PCA method might be useful to differentiate between patients with hepatocirrhosis and hepatitis from patients with liver cancer while lowering false-positive rate. These findings also suggest that a subset of the urinary nucleosides identified with metabonomics correlate better with cancer diagnosis than the traditional single tumor marker alpha-fetoprotein (AFP).     

石油污灌渠底泥生态毒性诊断研究

底泥样品采自沈阳东部石油污水灌渠的上、中、下游.进行了重金属Cu、Zn、Pb、Cd、矿物油含量分析和生态毒性试验.结果表明,所有底泥均有污染物积累.矿物油含量为408～118 300 mg·kg^-1,Cu为17.83～78.53 mg·kg^-1,Zn为35.76～155.16 mg·kg^-1,Pb为8.50～31.03 mg·kg^-1,Cd为0.1 mg·kg^-1～1.0mg·kg^-1.底泥对高等植物有不同程度的生长抑制或刺激效应,对蚯蚓有急性致死及慢性亚致死效应.种子发芽根伸长抑制率为-29.81%～93.8%,蚯蚓14d死亡率最大值为100%.蚯蚓14d和28d体重增长抑制率分别为-36.6%～6.08%和-40.4%～6.1%.研究表明,长期石油污水灌溉导致河道底泥中污染物的积累和较强生态毒性.     

辐照地被竹突变体DNA多态性分析

利用ISSR分子标记技术对γ-射线(铯137)辐照地被竹突变体植株的基因组DNA变异进行检测和分析,结果表明从100条ISSR引物中筛选得到多态性高、重复性好的引物21条,ISSR的多态性主要表现为扩增片段的增减和扩增片段长度的差异,不同的突变株系中,多态性比率为19.46％ ～ 72.39％,反映了各突变体中遗传物质...     

Interactions among Candidate Genes Selected by Meta-Analyses Resulting in Higher Risk of Ischemic Stroke in a Chinese Population

Ischemic stroke (IS) is a multifactorial disorder caused by both genetic and environmental factors. The combined effects of multiple susceptibility genes might result in a higher risk for IS than a single gene. Therefore, we investigated whether interactions among multiple susceptibility genes were associated with an increased risk of IS by evaluating gene polymorphisms identified in previous meta-analyses, including methylenetetrahydrofolate reductase (MTHFR) C677T, beta fibrinogen (FGB, β-FG) A455G and T148C, apolipoprotein E (APOE) ε2–4, angiotensin-converting enzyme (ACE) insertion/deletion (I/D), and endothelial nitric oxide synthase (eNOS) G894T. In order to examine these interactions, 712 patients with IS and 774 controls in a Chinese Han population were genotyped using the SNaPshot method, and multifactor dimensionality reduction analysis was used to detect potential interactions among the candidate genes. The results of this study found that ACE I/D and β-FG T148C were significant synergistic contributors to IS. In particular, the ACE DD + β-FG 148CC, ACE DD + β-FG 148CT, and ACE ID + β-FG 148CC genotype combinations resulted in higher risk of IS. After adjusting for potential confounding IS risk factors (age, gender, family history of IS, hypertension history and history of diabetes mellitus) using a logistic analysis, a significant correlation between the genotype combinations and IS patients persisted (overall stroke: adjusted odds ratio [OR] = 1.57, 95% confidence interval [CI]: 1.22–2.02, P < 0.001, large artery atherosclerosis subtype: adjusted OR = 1.50, 95% CI: 1.08–2.07, P = 0.016, small-artery occlusion subtype: adjusted OR = 2.04, 95% CI: 1.43–2.91, P < 0.001). The results of this study indicate that the ACE I/D and β-FG T148C combination may result in significantly higher risk of IS in this Chinese population.     

A Network Flow-Based Method to Predict Anticancer Drug Sensitivity

Predicting anticancer drug sensitivity can enhance the ability to individualize patient treatment, thus making development of cancer therapies more effective and safe. In this paper, we present a new network flow-based method, which utilizes the topological structure of pathways, for predicting anticancer drug sensitivities. Mutations and copy number alterations of cancer-related genes are assumed to change the pathway activity, and pathway activity difference before and after drug treatment is used as a measure of drug response. In our model, Contributions from different genetic alterations are considered as free parameters, which are optimized by the drug response data from the Cancer Genome Project (CGP). 10-fold cross validation on CGP data set showed that our model achieved comparable prediction results with existing elastic net model using much less input features.     

DISIS: Prediction of Drug Response through an Iterative Sure Independence Screening

Prediction of drug response based on genomic alterations is an important task in the research of personalized medicine. Current elastic net model utilized a sure independence screening to select relevant genomic features with drug response, but it may neglect the combination effect of some marginally weak features. In this work, we applied an iterative sure independence screening scheme to select drug response relevant features from the Cancer Cell Line Encyclopedia (CCLE) dataset. For each drug in CCLE, we selected up to 40 features including gene expressions, mutation and copy number alterations of cancer-related genes, and some of them are significantly strong features but showing weak marginal correlation with drug response vector. Lasso regression based on the selected features showed that our prediction accuracies are higher than those by elastic net regression for most drugs.