Resveratrol Upregulates Cardiac SDF-1 in Mice with Acute Myocardial Infarction through the Deacetylation of Cardiac p53

Aims

We previously demonstrated that resveratrol (RSV) administration causes cardiac stromal cell-derived factor (SDF)-1 upregulation and can enhance the mobilization of stem cells in mice with acute myocardial infarction (AMI). However, the upstream signal transduction involved in SDF-1 regulation in the setting of AMI and RSV administration remains unclear. Because RSV is a sirtuin 1 (SIRT1) activator and SIRT proteins act as deacetylases, we investigated the role of SIRT1 in SDF-1 upregulation and its subsequent effects.

Methods and Results

In vitro experiments with H9C2 cardiomyocytes under hypoxia and serum-deprivation conditions showed that p53 acted upstream of SDF-1. RSV could not regulate SDF-1 effectively after SIRT1 silencing, indicating that it is dependent on SIRT1. Subsequently, male C57BL/6 mice were divided into four groups: 1) sham, 2) MI, 3) MI+RSV, and 4) MI+RSV plus nicotinamide, an inhibitor of the deacetylase activity of SIRT (MI+RSV+NAM). Compared with the sham mice, AMI caused a slight increase in the cardiac p53 level and resulted in significant SIRT1 downregulation and p53 acetylation or activation. Compared with the MI mice, MI+RSV administration improved the cardiac SDF-1 level and reversed the reduction of SIRT1 and the activation of p53. Furthermore, we observed less cardiac dysfunction in MI+RSV mice and determined that NAM abolished the effects of RSV.

Conclusions

RSV enhances cardiac SDF-1 excretion after AMI partially through a SIRT1 normalization/p53 inactivation pathway.     

A Novobiocin Derivative,XN4, Inhibits the Proliferation of Chronic Myeloid Leukemia Cells by Inducing Oxidative DNA Damage

XN4 might induce DNA damage and apoptotic cell death through reactive oxygen species (ROS). The inhibition of proliferation of K562 and K562/G01 cells was measured by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide). The mRNA levels of NADPH oxidase 1-5 (Nox1-5) genes were evaluated by qRT-PCR. The levels of extracellular reactive oxygen species (ROS), DNA damage, apoptosis, and cell cycle progression were examined by flow cytometry (FCM). Protein levels were analyzed by immunoblotting. XN4 significantly inhibited the proliferation of K562 and K562/G01 cells, with IC₅₀ values of 3.75±0.07 µM and 2.63±0.43 µM, respectively. XN4 significantly increased the levels of Nox4 and Nox5 mRNA, stimulating the generation of intracellular ROS, inducing DNA damage and activating ATM-γ-H2AX signaling, which increased the number of cells in the S and G2/M phase of the cell cycle. Subsequently, XN4 induced apoptotic cell death by activating caspase-3 and PARP. Moreover, the above effects were all reversed by the ROS scavenger N-acetylcysteine (NAC). Additionally, XN4 can induce apoptosis in progenitor/stem cells isolated from CML patients’ bone marrow. In conclusion, XN4-induced DNA damage and cell apoptosis in CML cells is mediated by the generation of ROS.     

The Detection of Inhibitors of the Sclerotinia sclerotiorum (Lib.) de Bary Extracellular Proteinases in Sunflower

Abstract: Water-soluble protein fractions from leaves, seeds and heads of sunflower were shown to contain inhibitors of trypsin, chymotrypsin and extracellular proteinases from Sclerotinia sclerotiorum , a pathogen of sunflower, and Colletotrichum lindemuthianum. These included bifunctional inhibitors of trypsin and subtilisin. Comparison with the patterns of inhibition of standard proteinases indicated that the major extracellular proteinases of S. sclerotiorum are subtilisin-like. It is speculated that the sunflower inhibitors play a role in conferring resistance to fungal infection.     

安吉小鲵种群数量和数量动态的研究

本文对分布于浙江省安吉县龙王山自然保护区的安吉小鲵（ Ｈｙｎｏｂｉｕｓａｍｊｉｅｎｓｉｓ） 的种群数量进行了调查和分析, 安吉小鲵分布区狭窄, 种群数量小, 由于环境变化, 处于濒危状态, 应加以保护。     

Dielectric properties of human fetal organ tissues at radio frequencies

The in vitro dielectric properties of human fetal organ tissues were measured in the frequency range from 100 kHz to 500 MHz at 24 °C. The dielectric measurements were performed by using a network analyzer (HP4195A) and a coaxial line capacitive sensor. The tested samples, including skin, muscle, heart, lung, liver, kidney, spleen, and brain tissues, were obtained from the legal abortion of five women with 14–16 week gestation periods. © 1996 Wiley-Liss, Inc.     

The effect of nutrient availability and temperature on chain length of the diatom, Skeletonema costatum

We determined the effects of temperature and nutrients on thechain length of a diatom, Skeletonema costatum, in batch cultureand enclosure experiments with estuarine water from San FranciscoBay, USA, using the recently developed CytoBuoy flow cytometer.Determination of the number of cells per diatom chain by CytoBuoyflow cytometer and associated software correlated well withbut was much more precise and time efficient than microscopicquantification. Increasing temperatures (from 6, 8 to 17°C)and nutrient concentrations induced high growth rates and dominanceby longer chains in a cultured S. costatum strain that was originallyacclimatized to a temperature range of 11–30°C. Similarly,a positive correlation between growth rate and chain lengthwas observed in S. costatum in batch culture and natural communitiesin enclosure experiments. Maximal chain lengths of S. costatumwere greater in natural populations than in the batch culture.Longer chains affect sinking rates and thus likely help thediatom remain suspended in the upper part of the water columnwhere physical and chemical parameters are more favorable forgrowth.     

NMR study of the exchange rates of allosterically responsive labile protons in the heme pockets of hemoglobin A.

1H NMR spectroscopy has been used to measure the proximal histidyl labile ring proton (NH) rates of exchange with bulk solvent in the individual subunits of hemoglobin (Hb) A. These protons displayed a substantial decrease in their exchange rates in comparison with related monomeric proteins and exhibited sensitivity to the quarternary state. With the beta subunit NH, the exchange behaviour was similar to an allosterically responsive subset of protons, which have been identified using 1H-3H methods (Englander, J.J., R. Rogero, and S. W. Englander, 1983, J. Mol. Biol. 169:325-344). Assuming similar exchange mechanisms for the two subunits, the NMR data suggested a more flexible alpha than beta subunit in Hb A.     

促胰液素和胆囊收缩素族激素对豚鼠肝胆汁分泌的影响

用具备胃瘘和胆瘘的豚鼠于人工维持胆汁酸池恒定的条件下,观察促胰液素(SEC)和胆囊收缩素(CCK)族激素[包括雨蛙肽(CAE)、五肽胃泌素(G5)和内源性CCK]对肝胆汁分泌的影响及其相互作用。结果表明:静脉灌注SEC、CAE或肠内灌注左旋苯丙氨酸(L-PHE,促内源性CCK释放剂)后,胆汁流量、胆汁HCO~-_3和Cl~-排出量均显著增多,并呈剂量-效应关系,但静脉注射G5则无利胆效应。在恒速灌注SEC的背景下,CAE或CCK对胆汁HCO~-_3排出的效应分别大于它们单独给予时的效应(P<0.05或P<0.01)。这些激素对胆汁酸的排出量均无影响。上述结果表明,SEC,CAE和内源性CCK均有利胆作用,所刺激的肝胆汁属于不依赖胆汁酸部分。G5则无利胆效应。对胆汁中HCO~-_3的排出,SEC与CAE或内源性CCK间有相互加强作用。     

Eimeria sinaitae n. sp. (Apicomplexa: Eimeriidae) from the Rock Agama (Agama sinaita) in Saudi Arabia

Eimeria sinaitae n. sp. is described from the gall bladder of Agama sinaita from Wasie, Saudi Arabia. Sporulated oocysts are elongate-ellipsoid 34.4 times 22.0 (29.0–40.0 times 17.4–24.5) μm. Oocyst wall is smooth, greenish yellow, 1.2 (1.0–1.4) μm thick, and two-layered. Micropyle, polar granule, and oocyst residuum are absent. Sporocysts are ellipsoid 11.4 times 7.6 (9.8–15.0 times 6.7–9.0) μm. Sporocyst residuum is present. The sporocysts lack a Stieda body. Sporozoites are crescent-shaped, blunt at one end and tapered at the other. Eimeria species from Agamidae are compared.