Sphingosine kinase 1 regulates HMGB1 translocation by directly interacting with calcium/calmodulin protein kinase II-δ in sepsis-associated liver injury

Previously, we confirmed that sphingosine kinase 1 (SphK1) inhibition improves sepsis-associated liver injury. High-mobility group box 1 (HMGB1) translocation participates in the development of acute liver failure. However, little information is available on the association between SphK1 and HMGB1 translocation during sepsis-associated liver injury. In the present study, we aimed to explore the effect of SphK1 inhibition on HMGB1 translocation and the underlying mechanism during sepsis-associated liver injury. Primary Kupffer cells and hepatocytes were isolated from SD rats. The rat model of sepsis-associated liver damage was induced by intraperitoneal injection with lipopolysaccharide (LPS). We confirmed that Kupffer cells were the cells primarily secreting HMGB1 in the liver after LPS stimulation. LPS-mediated HMGB1 expression, intracellular translocation, and acetylation were dramatically decreased by SphK1 inhibition. Nuclear histone deacetyltransferase 4 (HDAC4) translocation and E1A-associated protein p300 (p300) expression regulating the acetylation of HMGB1 were also suppressed by SphK1 inhibition. HDAC4 intracellular translocation has been reported to be controlled by the phosphorylation of HDAC4. The phosphorylation of HDAC4 is modulated by CaMKII-δ. However, these changes were completely blocked by SphK1 inhibition. Additionally, by performing coimmunoprecipitation and pull-down assays, we revealed that SphK1 can directly interact with CaMKII-δ. The colocalization of SphK1 and CaMKII-δ was verified in human liver tissues with sepsis-associated liver injury. In conclusion, SphK1 inhibition diminishes HMGB1 intracellular translocation in sepsis-associated liver injury. The mechanism is associated with the direct interaction of SphK1 and CaMKII-δ.Subject terms: Hepatotoxicity, Sepsis     

Effects of larval competition on survival and growth in Mediterranean fruit flies

1. Larval success was compared when one, two, or three egg clutches were laid in kumquat fruits (≈ 10 ml in volume) either successively on the same day or at the rate of one clutch per day. 2. Increased clutch density was associated with a significant decrease in larval survival rate and non‐significant decreases in larval growth rate and pupal mass. 3. Larval and pupal parameters showed significantly larger variance when clutches were laid on successive days than on the same day, suggesting a competitive advantage for older larvae over younger larvae. 4. The results suggest that, in small fruit, reduced fitness due to larval competition may act against possible fitness benefits due to social facilitation among adult females, hence reducing the likelihood of non‐linear population dynamics caused by processes such as the Allee effect.     

Drosophila female germline stem cells undergo mitosis without nuclear breakdown

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香荚兰种子的无菌萌发试验

香荚兰(Vanilla planifolia)是兰科、香荚兰属植物,主产于湿热地区。香荚兰的果实是国际上重要的食用香料的原料。大约在1960年,我国引入香荚兰试栽。生产上,通常用扦插法繁殖;但如用种子繁殖,虽然结实较晚(约7至8年开始结实,较扦插苗晚4—5年),但结实期长,盛产期可维持约15年。而且,在杂交育种过程中,一定要用种子繁殖。     

云南山楂茎尖的离体培养及其无性系快速繁殖

用云南山楂(Crataegus scabrifolia(Franch.)Rehd.)成年树茎尖和实生芽两种不同发育阶段的材料为外殖体,诱导它们休眠芽萌动,丛生芽条并诱导芽条生根。实验结果如下:1.以成年态的云南山楂侧芽为外植体,培养在附加IAA 0.1—0.5mg/l+6-BA 1-2mg/l的MS培养基上可诱导芽的萌发;将芽继代培养在附加0.5—1mg/l 6-BA的SH或MS培养基上,40天后芽数增殖4—6倍;将芽条截下置于1/2MS培养基上,附加不同浓度的IAA或IBA,可得到50—80％的生根率。2.以实生芽为外殖体,在相同条件下,则20天后芽数增殖便可获4—6倍;98％以上生根。结果表明:云南山楂的幼年态要比成年态易脱分化和再分化。     

重楼属植物的免疫血清学研究

以海南重楼(Paris dunniana),花叶重楼(P.marmorata),多叶重楼(P.polyphylla),凌云重楼(P.cronquistii),五指莲(P.axialis),滇重楼(Paris polyphylla var.yunnanensis)等六种重楼属植物的根茎为材料,提取分离其球蛋白组份作为抗原,免疫家兔得到相应的抗血清。通过免疫双扩散,聚丙烯酰胺凝胶电泳、免疫电泳、免疫吸收试验以及酶标免疫等方法,研究了重楼属上述六个种和变种的血清学行为以及他们之间的相互关系。在此基础上,用不加权算术平均对群法(UPGMA)经成聚运算,得到基于平均吸收相似系数(Sabs.mean.)和Jaccard's结合系数的两种表相图,这两种表相图的结果是一致的。花叶重楼与多叶重楼有较大的血清反应相似性,五指莲与滇重楼有最大的血清反应相似性。多型种P.polyphylla在形态上的较大变异与血清反应分析的结果是一致的,而且血清反应相似性分析支持了从形态分析得出的假设:Paris dunniana在重楼属的系统发生中是一比较原始的种。     

玉米素核苷的酶标免疫测定法

牛血清白蛋白-玉米素核苷(BSA-ZR)的兔抗血清对玉米素核苷具有很高的亲和性,而且专一性强,除了玉米素外,对其它一些细胞分裂素如激动素(KT)的交叉反应甚微。用辣根过氧化物酶(HRP)作为标记物的酶标免疫法,由于它的灵敏度高,相当于几十毫克量的样品就可以测出细胞分裂素的含量。测定范围在0.25—50pmol之间,测定范围较广。由于该方法专一性高,植物组织的粗提取物可以直接用于测定。避免了提取分离的繁琐程序,使得测定方法较简便、快速,可成批进行,适用于一般实验室。用该方法测得风信子(Hyacinthus orientalis L.)各部分的细胞分裂含量(以玉米素核苷计)在10—60×10~(-9)克/克鲜重,即10—60ng/g F.W.。     

Stimulatory effects of human pancreatic polypeptide on rat pancreatic acini

The effect of human pancreatic polypeptide (HPP) on rat pancreatic acini has been studied. It was found that HPP stimulated amylase and lipase release from the acini. The secretory response of acini to HPP was dose-dependent in a sigmoidal fashion. Between 10(-9) M and 10(-8) M concentration of HPP there was a slow increase of enzyme release to about 40-60% over basal release. At concentrations of HPP above 10(-8) M there was a rapid increase of enzyme release, amounting to 4-6 times over basal release at 10(-6) M concentration of HPP. The potency of HPP compared to other secretagogues at 10(-7) M concentration was 45% of CCK, 60% of carbachol and 75% of secretin. HPP did not inhibit the effect of CCK, secretin and carbachol on amylase release. The amylase release stimulated by HPP was accompanied by an increase in 45Ca2+ efflux. Atropine or dibutyryl cyclic GMP did not influence the effect of HPP. It is concluded that HPP stimulates the release of enzymes from rat pancreatic acini and that Ca2+ may be a mediator for this secretion.