苦丁茶防晒组分萃取工艺的可视化分析

对采用超声辅助法萃取苦丁茶防晒组分进行了较为系统的研究。选择萃取时间、萃取剂体积分数、萃取温度、样品细度4个主要影响因素,运用多因素多水平可视化设计法安排实验。以防晒光区的紫外吸收面积值作为防晒组分萃取含量的实验评定指标。用自主提出的多因素多水平实验结果可视化分析方法对多维空间实验数据进行分析。得出当ρ(苦丁茶)=0.20 g/L时,最佳工艺范围为萃取时间30～60 min、萃取剂体积分数φ(C2H5OH)为50%～70%、萃取温度50～65℃、萃取样品细度140～160目。     

A new technique for studying the stylet tracks of homopteran insects in hand-sectioned plant tissue using light or epifluorescence microscopy

Homopteran insects, such as aphids, psyllids and scales, inject a proteinaceous salivary sheath into their host plant tissue during feeding. This sheath, also referred to as a stylet track, remains in the tissue after the stylets are withdrawn, and is useful for studying plant resistance to insects and plant virus transmission. We describe a new method for studying stylet tracks. Hand microtome sectioned plant material was fixed and cleared in ethanol. The stylet tracks were stained with acid fuchsin and counterstained with aniline blue or fast green. The acid fuchsin stained stylet tracks were pink to red under light microscopy, and orange under TRITC epifluorescence. Stylet tracks in unstained sections autofluoresced under DAPI epifluorescence. This new technique is significantly faster and less complex than previous techniques, and permitted visualization of stylet tracks with light or epifluorescence microscopy within 1 hr of collecting fresh plant material. The technique was also applicable to a broad range of homopterans and plant taxa and provided excellent photomicrographs.     

The Whole Genome Expression Analysis using Two Microarray Technologies to Identify Gene Networks That Mediate the Myocardial Phenotype of CD36 Deficiency

We have previously shown that CD36 is a membrane protein that facilitates long chain fatty acid (FA) transport by muscle tissues. We also documented the significant impact of muscle CD36 expression on heart function, skeletal muscle insulin sensitivity as well as on overall metabolism. To identify a comprehensive set of genes that are differentially regulated by CD36 expression in the heart, we used two microarray technologies (Affymetrix and Agilent) to compare gene expression in heart tissues from CD36 KnocK-Out (KO-CD36) versus wild type (WT-CD36) mice. The obtained results using the two technologies were similar with around 35 genes differentially expressed using both technologies. Absence of CD36 led to down-regulation of the expression of three groups of genes involved in pathways of FA metabolism, angiogenesis/apoptosis and structure. These data are consistent with the fact that the CD36 protein binds FA and thrombospondin 1 invoved respectively in lipid metabolism and anti-angiogenic activities. In conclusion, our findings led to validate our data analysis workflow and identify specific pathways, possibly underlying the phenotypic abnormalities in CD36 Knock -Out hearts.     

Transferrin Modifications and Lipid Peroxidation: Implications in Diabetes Mellitus

Free iron is capable of stimulating the production of free radicals which cause oxidative damage such as lipid peroxidation. One of the most important mechanisms of antioxidant defense is thus the sequestration of iron in a redox-inactive form by transferrin. In diabetes mellitus, increased oxidative stress and lipid peroxidation contribute to chronic complications but it is not known if this is related to abnormalities in transferrin function. In this study we investigated the role of transferrin concentration and glycation. The antioxidant capacity of apotransferrin to inhibit lipid peroxidation by iron-binding decreased in a concentration-dependent manner from 89% at <formula>≥2 mg/ml</formula> to 42% at 0.5 mg/ml. Pre-incubation of apotransferrin with glucose for 14 days resulted in a concentration-dependent increase of glycation: 1, 5 and 13 μmol fructosamine/g transferrin at 0, 5.6 and 33.3 mmol/l glucose respectively, p<0.001. This was accompanied by a decrease in the iron-binding antioxidant capacity of apotransferrin. In contrast, transferrin glycation by up to 33.3 mmol/l glucose did not affect chemiluminescence-quenching antioxidant capacity, which is iron-independent. Colorimetric evaluation of total iron binding capacity in the presence of an excess of iron (iron/transferrin molar ratio=2.4) also decreased from 0.726 to 0.696 and 0.585 mg/g transferrin after 0, 5.6 and 33.3 mmol/l glucose, respectively, p<0.01. In conclusion, these results suggest that lower transferrin concentration and its glycation can, by enhancing the pro-oxidant effects of iron, contribute to the increased lipid peroxidation observed in diabetes.     

Study on the Interaction Mechanism of 2‐Aminoanthraquinone with Calf Thymus DNA

By utilizing multispectrosopic techniques, the toxic interaction of 2‐aminoanthraquinone (2‐AAQ) with calf thymus deoxyribonucleic acid (ctDNA) was investigated in vitro under simulated physiological conditions. The experimental results proved that 2‐AAQ has a toxic interaction with ctDNA. The binding capacity of DNA with 2‐AAQ is diminishing as the pH value of system increasing in the optimization of experimental condition. Moreover we selected pH 7.4, which is nearly physiological condition to enhance the practical significance. According to the Stern–Volmer equation, the quenching was the static quenching process. And the quenching constant can be derived from the fluorescence quenching spectrogram. Ultraviolet absorption spectra and the change in the fluorescence intensity at different ionic strengths further indicated that there was electrostatic binding between 2‐AAQ and ctDNA. The circular dichroism experiment showed that the DNA conformation varied from B to A conformation. The basic group enhanced after 2‐AAQ embedding. The double helix is more compact, and the DNA conformation changes. © 2013 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:272‐278, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/jbt.21487     

A Novel Community of Acidophiles in an Acid Mine Drainage Sediment

A sediment sample (pH 2.5) was collected at an acid mine drainage site in Anhui, China. The present acidophilic microbial community in the sediment was studied with a 16S rRNA gene clone library. Small-subunit rRNA genes were PCR amplified, cloned and screened by amplified rDNA restriction analysis (ARDRA). Subsequently, 10 different clones were identified and they were affiliated with Acidobacteria, β/γ-Proteobacteria, δ-Proteobacteria, Nitrospira, Candidate division TM7, and Low G + C Gram-positives. Phylogenetic analysis of 16S rRNA gene sequences revealed a diversity of acidophiles in the sediment that were mostly novel. Unexpectedly, 16S rRNA gene sequences affiliated with δ-Proteobacteria were found to constitute more than 60% of clone library. To our knowledge, this is the first occasion that bacteria of δ-Proteobacteria have been found dominant in the acidic habitat. Anaerobic sulfate- or metal reduction is the predominant physiological trait of bacteria of this subdivision. The high sulfate, ferric iron and the presence of bioavailable carbon in the anaerobic microenvironment may result in the dominance of bacteria of δ-Proteobacteria.     

珍稀食药用菌——蜜环菌的开发与应用

蜜环菌是一种与传统中药天麻共生的药用真菌,其子实体、菌丝和菌索都可以入药,具有很高的研究开发价值,目前蜜环菌因具有极高的营养保健功能而倍受关注,国内外市场均有销售由蜜环菌及其多糖等提取物制成的药品和保健品。通过综述了蜜环菌的生物学特性、营养化学成分和药理作用的研究情况,并介绍了几种蜜环菌产品的制作方法和保健功能,旨在为蜜环菌的深入研究提供依据,并促进蜜环菌新型保健品或药品的开发,以满足国内外市场的需求。     

法尼酯X受体对肝脂酶表达的影响

目的:探讨法尼酯X受体(farnesoid X receptor,FXR)对肝脂酶(hepatic lipase,HL)表达的影响。方法:用FXR激动剂CDCA作用人肝癌细胞株(HepG2),用RT-PCR和Western blotting检测HL的表达情况。结果:用不同浓度的CDCA(25μmol/L、50μmol/L、75μmol/L)分别作用HepG2细胞6h、12h、24h、48h后,HL的mRNA和蛋白质水平呈时间和剂量依赖性下调。结论:FXR激动剂可抑制肝脂酶的表达。     

Coenzymes as fossils of an earlier metabolic state

Summary A metabolic system composed of nucleic acid enzymes is proposed to have existed prior to the evolution of ribosomal protein synthesis. Vestiges of these nucleic acid enzymes persist in contemporary coenzymes. This proposal rationalizes the fact that many coenzymes are nucleotides or heterocyclic bases which could be derived from nucleotides.     

Production of gluconic acid and 2-ketogluconic acid by Klebsiella aerogenes NCTC 418

2-Ketogluconic acid and, to a lesser extent, gluconic acid were found to be major products of glucose catabolism by phosphate-limited cultures of Klebsiella aerogenes NCTC 418, and together accounted for up to 46% of the glucose carbon that was metabolized.Although the concentrations of both acids increased sub-stantially at low growth rates, their specific rates of synthesis decreased markedly, as did the proportion of glucose converted into these products.Determination of the affinity constant, for glucose, of phosphate-limited organisms showed it to be not significantly different from that of glucose-limited organisms (K _s 50 M), indicative of the phosphotransferase uptake system. And since these organisms possessed an active glucose 6-phosphate dehydrogenase, and had no detectable glucose dehydrogenase activity, it was concluded that gluconic acid and 2-ketogluconic acid arose from their corresponding phosphorylated metabolites, and not directly from glucose.