Involvement of OsPht1;4 in phosphate acquisition and mobilization facilitates embryo development in rice

Phosphate (Pi) transporters mediate acquisition and transportation of Pi within plants. Here, we investigated the functions of OsPht1;4 (OsPT4), one of the 13 members of the Pht1 family in rice. Quantitative real‐time RT‐PCR analysis revealed strong expression of OsPT4 in roots and embryos, and OsPT4 promoter analysis using reporter genes confirmed these findings. Analysis using rice protoplasts showed that OsPT4 localized to the plasma membrane. OsPT4 complemented a yeast mutant defective in Pi uptake, and also facilitated increased accumulation of Pi in Xenopus oocytes. Further, OsPT4 genetically modified (GM) rice lines were generated by knockout/knockdown or over‐expression of OsPT4. Pi concentrations in roots and shoots were significantly lower and higher in knockout/knockdown and over‐expressing plants, respectively, compared to wild‐type under various Pi regimes. ³³Pi uptake translocation assays corroborated the altered acquisition and mobilization of Pi in OsPT4 GM plants. We also observed effects of altered expression levels of OsPT4 in GM plants on the concentration of Pi, the size of the embryo, and several attributes related to seed development. Overall, our results suggest that OsPT4 encodes a plasma membrane‐localized Pi transporter that facilitates acquisition and mobilization of Pi, and also plays an important role in development of the embryo in rice.     

Brummer‐dependent lipid mobilization regulates starvation resistance in Nilaparvata lugens

Energy homeostasis is an essential characteristic of all organisms, requiring fluctuation in energy accumulation, mobilization, and exchange with the external environment. In insects, energy mobilization is under control of the lipase brummer (bmm), which regulates nutritional status by hydrolyzing the ester bonds in triacylglycerol (TAG). In the present study, we investigated the role of bmm in the lipid mobilization and starvation resistance in the brown planthopper (BPH; Nilaparvata lugens), which is economically one of the most important rice pests in Asia. A severe decrease in TAG and glyceride contents was observed in the starved BPHs, while there was a partial rescue after refeeding. The starvation condition caused a significant increase in the expression levels of Nlbmm, and supplement of food after starvation dramatically reduced the Nlbmm expression. Sucrose rescue after starvation significantly suppressed the expression of Nlbmm, while caused an accumulation of TAG and glyceride. Knockdown of Nlbmm by double‐stranded RNA treatment extended the lifespan to starvation, whereas it increased the level of TAG and glyceride in the BPHs. The decreased lipolysis rate by dsNlbmm‐treated BPHs eventually resulted in increase of starvation resistance. These data demonstrated that the regulation of energy homeostasis by Nlbmm affects starvation resistance, probably through lipid mobilization control in N. lugens.     

Effect of short-term treatment with a monoclonal antibody to P-selectin on balloon catheter-induced: Intimal hyperplasia,re-endothelialization,and attenuation of endothelial-dependent relaxation

The effects of an anti-P-selectin monoclonal antibody (MAb, PB1.3; Cytel Corporation) on neoendothelialization; neoendothelial function, as evidenced by acetylcholine-induced relaxation (nitric oxide formation); and intimal hyperplasia following embolectomy catheter-induced injury to the rabbit thoracic aorta were investigated. Catheter injury was induced in two groups of New Zealand White rabbits. One group received no treatment, while the second group received short-term treatment with the MAb (i.p., immediately before and 12 h after induction of catheter injury). A third group underwent a sham operation and served as uninjured controls. Following sacrifice at 2 weeks after injury, aortic rings were assessed for degree of intimal hyperplasia, neoendothelial morphology (scanning electron microscopy), and acetylcholine-induced relaxation. Aortic tissue from catheter-injured animals that received treatment exhibited improved neoendothelial morphology, as compared with tissue from untreated but catheterized animals; however, no statistically significant attenuation of the hyperplastic response or improvement in the attenuated neoendothelial-dependent acetylcholine-induced relaxant response that is characteristic of neoendothelium that forms after catheter denudation was observed. These data suggest that short-term attenuation of P-selectin-mediated polymorphonuclear leukocyte (PMN)/endothelium, PMN/platelet interactions, and/or thrombin formation beneficially affects neoendothelialization of the vascular wall following balloon catheter-induced injury.     

Regulation of pharmacology by hetero-oligomerization between A1 adenosine receptor and P2Y2 receptor

Adenosine and ATP/UTP are main components of the purinergic system that modulate cellular and tissue functions via specific adenosine and P2 receptors, respectively. Here, we explored the possibility that A(1) adenosine receptor (A(1)R) and P2Y(2) receptor (P2Y(2)R) form heterodimers with novel pharmacological properties. Coimmunoprecipitation showed these receptors directly associate in A(1)R/P2Y(2)R-cotransfected HEK293T cells. Agonist binding by the A(1)R was significantly inhibited by P2Y(2)R agonists only in membranes from cotransfected cells. The functional activity of A(1)R, as indicated by the G(i/o)-mediated inhibition of adenylyl cyclase, in the cotransfected cells was attenuated by the simultaneous addition of A(1)R and P2Y(2)R agonists. The increase in intracellular Ca(2+) levels induced by P2Y(2)R activation of G(q/11) was synergistically enhanced by the simultaneous addition of an A(1)R agonist in the coexpressing cells. These results suggest that oligomerization of A(1)R and P2Y(2)R generates a unique complex in which the simultaneous activation of the two receptors induces a structural alteration that interferes signaling via G(i/o) but enhances signaling via G(q/11).     

Productivity of high-latitude lakes: climate effect inferred from altitude gradient

Climate change is predicted to be dramatic at high latitudes. Still, climate impact on high latitude lake ecosystems is poorly understood. We studied 15 subarctic lakes located in a climate gradient comprising an air temperature difference of about 6°C. We show that lake water productivity varied by one order of magnitude along the temperature gradient. This variation was mainly caused by variations in the length of the ice‐free period and, more importantly, in the supply of organic carbon and inorganic nutrients, which followed differences in terrestrial vegetation cover along the gradient. The results imply that warming will have rapid effects on the productivity of high latitude lakes, by prolongation of ice‐free periods. However, a more pronounced consequence will be a delayed stimulation of the productivity following upon changes of the lakes terrestrial surroundings and subsequent increasing input of elements that stimulate the production of lake biota.     

急性ST段抬高型心肌梗死患者血清NT-proBNP、P-selectin联合IMA预测PCI术后心电图ST段回落的临床价值研究

摘要 目的：探讨急性ST段抬高型心肌梗死（ASTEMI）患者血清N末端B型利钠肽前体（NT-proBNP）、P-选择素（P-selectin）联合缺血修饰白蛋白（IMA）预测经皮冠状动脉介入治疗（PCI）术后心电图ST段回落（STR）不良的临床价值。方法：选取2020年1月～2022年7月南京医科大学第二附属医院急诊科收治的100例ASTEMI患者,根据PCI术后心电图STR分为STR不良组和STR良好组,另选取同期50名体检健康志愿者为对照组。采用酶联免疫吸附法检测血清NT-proBNP、P-selectin和IMA水平。采用多因素Logistic回归分析ASTEMI患者PCI术后心电图STR不良的影响因素,采用受试者工作特征（ROC）曲线分析血清NT-proBNP、P-selectin、IMA水平对ASTEMI患者PCI术后心电图STR不良的预测价值。结果：与对照组比较,ASTEMI组PCI术前血清NT-proBNP、P-selectin和IMA水平升高（P＜0.05）。根据心电图STR将ASTEMI患者分为STR不良组35例和STR良好组65例。STR不良组与STR良好组PCI术后血清NT-proBNP、P-selectin和IMA水平低于PCI术前（P＜0.05）;STR不良组PCI术前和PCI术后血清NT-proBNP、P-selectin和IMA水平高于STR良好组（P＜0.05）。STR不良组Killip分级≥2级比例和肌钙蛋白I高于STR良好组,ST段偏差总和低于STR良好组（P＜0.05）。多因素Logistic回归分析显示,Killip分级≥2级和NT-proBNP、P-selectin、IMA升高为ASTEMI患者PCI术后心电图STR不良的独立危险因素（P＜0.05）。ROC曲线分析显示,血清NT-proBNP、P-selectin联合IMA预测ASTEMI患者PCI术后心电图STR不良的曲线下面积（AUC）大于NT-proBNP、P-selectin和IMA单独预测。结论：血清NT-proBNP、P-selectin和IMA水平升高与ASTEMI患者PCI术后心电图STR不良独立相关,三者联合预测ASTEMI患者PCI术后心电图STR不良的价值较高。     

P—选择素凝集素—EGF功能域的克隆、表达及其单克隆抗体制备

制备特异性抗人P 选择素的凝集素 表皮生长因子 (L EGF)功能域的单克隆抗体。利用特异引物 ,通过RT PCR从外周血血小板中扩增出人P 选择素的L EGF功能域基因 ,将其克隆至pET42b( )载体中 ,测序验证后转染大肠杆菌BL2 1,经诱导表达了C端融合 6×His的蛋白质。融合蛋白质经分离纯化后 ,免疫Balb/c小鼠 ,应用杂交瘤技术 ,通过间接ELISA筛选阳性克隆。获得 3株可稳定分泌抗L EGF功能域单抗的杂交瘤细胞株 (B10、F3和H5 )。其亚型分别为IgG2 、IgG1和IgG3;轻链均为κ型。所获的单抗对LPS刺激活化的人脐静脉内皮细胞均有特异性结合反应 ,并可在体外阻断经凝血酶激活的血小板与中性粒细胞间的粘附。表明所获的单抗可特异性识别结合天然P 选择素 ,具有体外抗活化血小板与中性粒细胞粘附的功能 ,为进一步应用此单抗进行P 选择素结构和功能及抗粘附治疗研究提供了实验基础。     

Rapid mobilization of ferritin iron by ascorbate in the presence of oxygen

L-(—)-ascorbate mobilizes iron from horse-spleen ferritin in the presence of oxygen at pH 8.0. The reaction is strongly stimulated by Cu²⁺. Dehydroascorbate and other stable oxidation products of ascorbate are ineffective. We present evidence that monodehydroascorbate mobilizes ferritin iron by reduction.