Microelectrode studies of amphotericin B on Na+ and K+ conductance in bullfrog cornea

Addition of 10(-5) M amphotericin B to the tear solution of an in vitro preparation of the frog cornea increased the transepithelial conductance, gt, and decreased the apical membrane fractional resistance, f(R0), in the presence or absence of tear Na+ and Cl-. In the presence of tear Na+ and Cl-, amphotericin B increased the short-circuit current, Isc, from 3.9 to 8.8 microA.cm-2 and changed the intracellular potential, V0, from -48.5 to -17.9 mV probably due to a higher increase in the Na+ than in the K+ conductance. In the absence of tear Na+ and Cl-, amphotericin B decreased Isc from 5.5 to about 0 microA.cm-2 due to K+ (and possibly Na+) flux from cell to tear and changed V0 from -35.4 to -63.6 mV due to the increase in conductance of both ions. Increase in the tear K+ from 4 to 79 mM (in exchange for choline), in the presence of amphotericin B and absence of tear Na+ and Cl-, decreased f(R0) from 0.09 to 0.06, increased gt from 0.23 to 0.31 mS, increased Isc from 0.63 to 7.3 microA.cm-2, and changed V0 from -65.5 to -17.3 mV due to the change in EK in the presence of a high conductance in the tear membrane. Similar effects were observed with an increase of tear Na+. Results support the concept that the Na+ conductance opened by amphotericin B in the apical membrane is greater than the K+ conductance. Previously observed transepithelial effects of the ionophore may be explained mostly on the basis of its effect on the apical membrane.     

Gene therapy with iNOS provides long-term protection against myocardial infarction without adverse functional consequences

Previous studies have shown that gene therapy with inducible nitric oxide synthase (iNOS) protects against myocardial infarction at 3 days after gene transfer. However, the long-term effects of iNOS gene therapy on myocardial ischemic injury and cardiac function are unknown. To address this issue, we used a recombinant adenovirus 5 (Ad5) vector (Av3) with deletions of the E1, E2a, and E3 regions, which enables long-lasting recombinant gene expression for at least 2 mo due to lack of inflammation. Mice received intramyocardial injections in the left ventricular (LV) anterior wall of Av3/LacZ (LacZ group) or Av3/iNOS (iNOS group); 1 or 2 mo later, they were subjected to myocardial infarction (30-min coronary occlusion followed by 4 h of reperfusion). Cardiac iNOS gene expression was confirmed by immunoblotting and activity assays at 1 and 2 mo after gene transfer. In the iNOS group, infarct size (percentage of risk region) was significantly reduced (P < 0.05) both at 1 mo (24.2 +/- 3.4%, n = 6, vs. 48.0 +/- 3.6%, n = 8, in the LacZ group) and at 2 mo (23.4 +/- 3.1%, n = 8, vs. 36.6 +/- 2.4%, n = 7). The infarct-sparing effects of iNOS gene therapy were as powerful as those observed 24 h after ischemic preconditioning (23.1 +/- 3.4%, n = 10). iNOS gene transfer had no effect on LV function or dimensions up to 8 wk later (echocardiography). These data demonstrate that iNOS gene therapy mediated by the Av3 vector affords long-term (2 mo) cardioprotection without inflammation or adverse functional consequences, a finding that provides a rationale for further preclinical testing of this therapy.     

Antiplatelet actions of aporphinoids from Formosan plants

Seventeen aporphines were tested for antiplatelet activity. L-(+)-hemovine HCl and 7-hydroxydehydrothalicsimidine strongly inhibited platelet aggregation induced by adenosine 5'-diphosphate (ADP), arachidonic acid (AA), collagen, and platelet-activating factor (PAF). The latter showed the strongest antiplatelet activity with an IC50 of 70.4 microM against AA-induced platelet aggregation.     

浑太流域洪涝灾害及其治理方略

抚顺、鞍山、辽阳等在内的中部城市群提供年用水量７．０×１０９ｍ３的７０％［５］,对辽宁经济发展与生态环境建设具有至关重要的作用．本文试图剖析浑河、太子河洪涝灾害问题,找出其成因与特点,从生态与工程结合角度提出治理方略,为防洪减灾,振兴经济服务．２　洪涝灾害成因分析２．１　洪涝灾害的一般分析　　洪涝灾害是天降暴雨和下垫面综合作用的结果．它通常依赖气象、水文地理和生态环境三方面因素．气象因素主要指暴雨,包括雨量、雨强和降雨落区．暴雨主要受大气环境制约,目前人类难以左右．然而,通过人工控制增减局地降雨…     

新城疫病毒F48E8株融合蛋白基因序列分析

本研究报道了新城疫病毒（ＮＤＶ）中国标准强毒株Ｆ４８Ｅ８融合蛋白（Ｆ）基因的序列。该基因核苷酸序列长度为１７００ｂｐ,编码由５５３个氨基酸组成的Ｆ０多肽。Ｆ０酶切激活部位序列为ＲＲＱＲＲ↓Ｆ,具有ＮＤＶ强毒的特征。Ｆ０中有３个主要由疏水性氨基酸组成的区域和６个可糖基化位点。经比较,ＮＤＶＦ４８Ｅ８株和Ｍｉｙａｄｅｒａ株、ＴｅｘａｓＧＢ株的氨基酸同源性分别为９３．６４％和９２．４１％。     

VIPR: A probabilistic algorithm for analysis of microbial detection microarrays

Background  

All infectious disease oriented clinical diagnostic assays in use today focus on detecting the presence of a single, well defined target agent or a set of agents. In recent years, microarray-based diagnostics have been developed that greatly facilitate the highly parallel detection of multiple microbes that may be present in a given clinical specimen. While several algorithms have been described for interpretation of diagnostic microarrays, none of the existing approaches is capable of incorporating training data generated from positive control samples to improve performance.     

“生物微核技术监测水质的污染”研究性学习案例

在提供＂生物微核技术监测水质的污染＂研究性学习案例的基础上,通过展现该研究性学习的过程,介绍了该案例的设计、实践操作过程与实践成果,并对该研究性学习的实施过程进行了教学反思。     

Activation of the Imprinted Dlk1-Dio3 Region Correlates with Pluripotency Levels of Mouse Stem Cells

Low reprogramming efficiency and reduced pluripotency have been the two major obstacles in induced pluripotent stem (iPS) cell research. An effective and quick method to assess the pluripotency levels of iPS cells at early stages would significantly increase the success rate of iPS cell generation and promote its applications. We have identified a conserved imprinted region of the mouse genome, the Dlk1-Dio3 region, which was activated in fully pluripotent mouse stem cells but repressed in partially pluripotent cells. The degree of activation of this region was positively correlated with the pluripotency levels of stem cells. A mammalian conserved cluster of microRNAs encoded by this region exhibited significant expression differences between full and partial pluripotent stem cells. Several microRNAs from this cluster potentially target components of the polycomb repressive complex 2 (PRC2) and may form a feedback regulatory loop resulting in the expression of all genes and non-coding RNAs encoded by this region in full pluripotent stem cells. No other genomic regions were found to exhibit such clear expression changes between cell lines with different pluripotency levels; therefore, the Dlk1-Dio3 region may serve as a marker to identify fully pluripotent iPS or embryonic stem cells from partial pluripotent cells. These findings also provide a step forward toward understanding the operating mechanisms during reprogramming to produce iPS cells and can potentially promote the application of iPS cells in regenerative medicine and cancer therapy.     

Conversion of squid pen by a novel strain Lactobacillus paracasei subsp. paracasei TKU010, and its application in antimicrobial and antioxidants activity

TKU010 was isolated from infant vomited milk and identified as Lactobacillus paracasei subsp. paracasei. TKU010 had desirable properties concerning its ability to withstand adverse conditions in the gastrointestinal tract. The hydrolysate of casein enhanced the growth of TKU010 most obviously (17.20-18.25 OD(660)), followed by the hydrolysate of SPP (16.00-15.06 OD(660)). Incubating with SPP, both the culture supernatant of TKU010 on the first day and the fourth day showed inhibitory activities on E. coli BCRC13086, F. oxysporum BCRC32121 and A. fumigatus BCRC30099. TKU010 culture supernatant (1% SPP) incubated for 3 days has high antioxidant activity; the DPPH scavenging ability was 75% per ml. Thus, TKU010 could be preferably used as a starter to produce fermented milk with possibly interesting organoleptic properties. Besides, we have shown that squid pen wastes can be utilized to generate a high value-added product, and have revealed its hidden potential in the production of biocontrol agents and functional foods.