A Mutant D‐Fructose‐6‐Phosphate Aldolase (Ala129Ser) with Improved Affinity towards Dihydroxyacetone for the Synthesis of Polyhydroxylated Compounds

A mutant of D ‐fructose‐6‐phosphate aldolase (FSA) of Escherichia coli, FSA A129S, with improved catalytic efficiency towards dihydroxyacetone (DHA), the donor substrate in aldol addition reactions, was explored for synthetic applications. The k_cat/K_M value for DHA was 17‐fold higher with FSA A129S than that with FSA wild type (FSA wt). On the other hand, for hydroxyacetone as donor substrate FSA A129S was found to be 3.5‐fold less efficient than FSA wt. Furthermore, FSA A129S also accepted glycolaldehyde (GA) as donor substrate with 3.3‐fold lower affinity than FSA wt. This differential selectivity of both FSA wt and FSA A129S for GA makes them complementary biocatalysts allowing a control over donor and acceptor roles, which is particularly useful in carboligation multi‐step cascade synthesis of polyhydroxylated complex compounds. Production of the mutant protein was also improved for its convenient use in synthesis. Several carbohydrates and nitrocyclitols were efficiently prepared, demonstrating the versatile potential of FSA A129S as biocatalyst in organic synthesis.     

Structure Identification of Triacylglycerols in the Seed Oil of Momordica Charantia L. Var. Abbreviata Ser.

Triacylglycerols (TGs) in the seed oil of Momordica charantia L. var. abbreviata Ser. (MCV) were separated by non-aqueous reversed-phase (NARP)-HPLC. Many of the TGs contain two different fatty acyl chains, such as palmitic (P), stearic (S), oleic (O), linoleic (L), and conjugated linolenic acid (CLn). Seven pairs of AAB/ABA-type TGs might present in the seed oil of MCV, namely CLnCLnP/CLnPCLn, CLnCLnS/CLnSCLn, CLnCLnO/CLnOCLn, CLnCLnL/CLnLCLn, SSCLn/SCLnS, OOCLn/OCLnO and LLCLn/LCLnL. The positional isomers of a AAB/ABA-type TGs pair yielded mass spectra showing a significant difference in relative abundance ratios of the fragment ions [AA]⁺ to [AB]⁺, which were produced by preferred losses of the fatty acid from the 1/3-position compared to the 2-position of the glycerol backbone. The precise stereospecific structures of the predominant regioisomers of TGs in AAB/ABA pairs were identified by atmospheric pressure chemical ionization mass spectrometry (APCI-MS) according to the special relative abundance ratios of the fragment ions [AA]⁺ to [AB]⁺. TGs with CLn occupying the sn-2 position in seven pairs of AAB/ABA might be major constituents of the oil, such as CLnCLnS, LCLnL, CLnCLnP, and so on. Some of the TGs which were isolated and collected as fractions from the seed oil of MCV by NARP-HPLC were further analyzed by ¹³C-NMR. ¹³C-NMR data of type-AAA TGs containing α-eleostearic acyl have been complemented.     

Delphi数据库的体系结构

本文介绍Ｄｅｌｐｈｉ数据库体系结构,并描述了使用它开发应用程序几种结构图。     

Ser/Thr-rich domains are associated with genetic variation and morphogenesis in Saccharomyces cerevisiae

Proteins containing regions of amino acid bias are often found in eukaryotes and are associated with particular functional groups. We have carried out a genomic analysis of yeast proteins containing regions with a significant bias of Ser and Thr residues. Our findings reveal that a high number are cell surface proteins or regulatory proteins involved in many aspects of cell differentiation. Furthermore, in Saccharomyces-related species, a highly significant correlation exists between the frequency of Ser-rich regions and DNA repeats, indicating that their generation may rely on similar factors. Cluster analysis shows that Ser/Thr-rich regions, located within the tandem repeats of cell surface proteins, are encoded to an increased frequency by UCU (Ser) and ACU/ACC (Thr), implying that mutational events that generate iterations could involve these codons. Replication slippage is proposed to be a contributing factor, as mounting evidence suggests that repeat generation in cell surface proteins can occur independently of meiosis. To reinforce this argument, we have discovered a premeiotic association between Mre11p, a nuclease involved in DNA repair, and ORFs encoding Ser/Thr-rich regions. Several macromolecules involved in the glycosylation and phosphorylation of proteins require Ser and Thr residues as binding sites. Ser/Thr-rich regions, through polymorphisms, are associated with the evolution of functional sites, particularly in providing motifs for glycosylation and phosphorylation. These results point to a Ser/Thr-biased somatic mutation mechanism that contributes to rapid evolution in yeast.     

Protective effect of fresh and processed Jalapeño and Serrano peppers against food lipid and human LDL cholesterol oxidation

The potential of fresh and processed Jalapeño and Serrano pepper extracts for the control of lipid oxidation in several systems was investigated. The assays used included β-carotene/linoleate model system, striped corn oil, ground pork meat and Cu(II)-induced oxidation of human low-density lipoprotein (LDL). The results showed that all extracts were effective in at least one system, although their potency varied. Extracts of smoked Jalapeño were particularly effective. The lipid-protective effect of the extracts was mainly due to the presence of phenolic compounds, but other phytochemicals, such as chlorophylls were also involved.     

癞葡萄水提物的降糖效果研究

为研究癞葡萄水提物对正常小鼠及四氧嘧啶型糖尿病小鼠血糖浓度的影响,将不同剂量(250mg/kg体重、500mg/kg体重和750mg/kg体重)的水提物灌胃给予禁食12h的正常小鼠和四氧嘧啶型糖尿病小鼠。试验结果表明,癞葡萄水提物对正常小鼠的血糖浓度没有影响,而对四氧嘧啶型糖尿病小鼠的血糖浓度有显著影响。其中500mg/kg剂量组糖尿病小鼠的血糖值在灌胃4h后较相应的初始血糖值下降45.28%,糖尿量提高38.39%;给予500mg/kg水提物治疗15d后,糖尿病小鼠血糖值较治疗前下降59.88%,同时对小鼠体重的恢复有一定的促进作用。结果表明癞葡萄水提物对四氧嘧啶型糖尿病小鼠具有良好的预防和治疗效果。     

Caffeic Acid Phenethyl Ester Suppresses Proliferation and Survival of TW2.6 Human Oral Cancer Cells via Inhibition of Akt Signaling

Caffeic acid phenethyl ester (CAPE) is a bioactive component extracted from honeybee hive propolis. Our observations indicated that CAPE treatment suppressed cell proliferation and colony formation of TW2.6 human oral squamous cell carcinoma (OSCC) cells dose-dependently. CAPE treatment decreased G1 phase cell population, increased G2/M phase cell population, and induced apoptosis in TW2.6 cells. Treatment with CAPE decreased protein abundance of Akt, Akt1, Akt2, Akt3, phospho-Akt Ser473, phospho-Akt Thr 308, GSK3β, FOXO1, FOXO3a, phospho-FOXO1 Thr24, phospho-FoxO3a Thr32, NF-κB, phospho-NF-κB Ser536, Rb, phospho-Rb Ser807/811, Skp2, and cyclin D1, but increased cell cycle inhibitor p27^Kip. Overexpression of Akt1 or Akt2 in TW2.6 cells rescued growth inhibition caused by CAPE treatment. Co-treating TW2.6 cells with CAPE and 5-fluorouracil, a commonly used chemotherapeutic drug for oral cancers, exhibited additive cell proliferation inhibition. Our study suggested that administration of CAPE is a potential adjuvant therapy for patients with OSCC oral cancer.     

癞葡萄降糖活性成分的提取及其降糖活性的研究

对癞葡萄中水溶性降糖活性成分的提取进行了研究.以水作为溶剂提取癞葡萄的降糖活性成分,通过10kdal的超滤膜将水提物分为二个组分,并对这两个组分分别进行了降糖活性动物实验.结果表明,大、小分子组分均有一定降糖效果,但相对分子量大于10kdal的组分降糖效果不显著;相对分子量小于10kdal的组分降糖活性显著,起着主要的降糖作用.     

CSF－1R部分基因在大肠杆菌中表达、抗融合蛋白血清制备及丝氨酸／苏氨酸磷酸化的初步研究

鼠巨噬细胞集落刺激因子－１受体（ｍＣＳＦ－１Ｒ）部分序列与质粒ｐＧＥＸ－２Ｔ谷胱苷肽转移酶（ＧＳＴ）融合，融合蛋白ＧＳＴ－ＣＤ－Ｐｓｔ（胞浆区），ＧＳＴ－ＣＴｅｒｍ（Ｃ－末端）和ＧＳＴ－ＫＩ（激酶插入区）成功地在大肠杆菌ＪＭ１０９株表达。初步结果指出：（１）ＧＳＴ－融合蛋白在体外激酶分析中可以作为底物；（２）由ＰＫＡ导致的磷酸化可能具有生理学意义；（３）ｍＣＳＦ－１Ｒ被ＣＫＩＩ磷酸化。３２Ｐ标记ＧＳＴ－ＣＤ－Ｐｓｔ的磷酸氨基酸分析证实，ｍＣＳＦ－１Ｒ的胞浆区丝氨酸上被磷酸化，已制备抗ＧＳＴ－ＣＴｅｒｍ，ＧＳＴ－ＫＩ和ＧＳＴ－ＣＤ－Ｐｓｔ兔抗体。抗血清的筛选通过野生型３２Ｄ－ＣＳＦ－１Ｒ转染子免疫沉淀进行。     

Amino acids,fatty acids,and dietary fibre in edible seaweed products

The nutritional compositions of 34 edible seaweed products of the Laminaria sp., Undaria pinnatifida, Hizikia fusiforme and Porphyra sp. varieties were analyzed.