Phototropins and Their LOV Domains：Versatile Plant Blue-Light Receptors

The phototropins phot1 and phot2 are plant blue-light receptors that mediate phototropism, chloroplast movements, stomatal opening, leaf expansion, the rapid Inhibition of hypocotyl growth in etiolated seedlings, and possibly solar tracking by leaves in those species in which It occurs. The phototroplns are plasma membrane-associated hydrophilic proteins with two chromophore domains （designated LOV1 and LOV2 for their resemblance to domains In other signaling proteins that detect light, oxygen, or voltage） in their Nterminal half and a classic serine/threonlne kinase domain in their C-terminal half. Both chromophore domains bind flavin mononucleotide （FMN） and both undergo light-activated formation of a covalent bond between a nearby cystelne and the C（4a） carbon of the FMN to form the signaling state. LOV2-cystelnyl adduct formation leads to the release downstream of a tightly bound amphlpathlc α-helix, a step required for activation of the klnase function. This cysteinyl adduct then slowly decays over a matter of seconds or minutes to return the photoreceptor chromophore modules to their ground state. Functional LOV2 is required for light-activated phosphorylation and for various blue-light responses mediated by the phototroplns. The function of LOV1 is still unknown, although It may serve to modulate the signal generated by LOV2. The LOV domain Is an ancient chromophore module found In a wide range of otherwise unrelated proteins In fungi and prokaryotes, the latter Including cyanobacterla, eubacterla, and archaea. Further general reviews on the phototropins are those by Celaya and Liscum （2005） and Christie and Briggs （2005）.     

Lipopolysaccharide enhances the production of nicotine-induced prostaglandin E2 by an increase in cyclooxygenase-2 expression in osteoblasts

Previous studies have indicated that lipopolysaccharide(LPS)from Gram-negative bacteria inplaque induces the release of prostaglandin E_2(PGE_2),which promotes alveolar bone resorption in periodontitis,and that tobacco smoking might be an important risk factor for the development and severity of periodontitis.We determined the effect of nicotine and LPS on alkaline phosphatase(ALPase)activity,PGE_2 production,and the expression of cyclooxygenase(COX-1,COX-2),PGE_2 receptors Ep1-4,and macrophage colonystimulating factor(M-CSF)in human osteoblastic Saos-2 cells.The cells were cultured with 10~(-3)M nicotinein the presence of 0,1,or 10μg/ml LPS,or with LPS alone.ALPase activity decreased in cells cultured withnicotine or LPS alone,and decreased further in those cultured with both nicotine and LPS,whereas PGE_2production significantly increased in the former and increased further in the latter.By itself,nicotine did notaffect expression of COX-1,COX-2,any of the PGE_2 receptors,or M-CSF,but when both nicotine and LPSwere present,expression of COX-2,Ep3,Ep4,and M-CSF increased significantly.Simultaneous addition of10~(-4)M indomethacin eliminated the effects of nicotine and LPS on ALPase activity,PGE_2 production,and M-CSF expression.Phosphorylation of protein kinase A was high in cells cultured with nicotine and LPS.Theseresults suggest that LPS enhances the production of nicotine-induced PGE_2 by an increase in COX-2 expres-sion in osteoblasts,that nicotine-LPS-induced PGE_2 interacts with the osteoblast Ep4 receptor primarily inautocrine or paracrine mode,and that the nicotine-LPS-induced PGE_2 then decreases ALPase activity andincreases M-CSF expression.     

法尼酯X受体对肝脂酶表达的影响

目的:探讨法尼酯X受体(farnesoid X receptor,FXR)对肝脂酶(hepatic lipase,HL)表达的影响。方法:用FXR激动剂CDCA作用人肝癌细胞株(HepG2),用RT-PCR和Western blotting检测HL的表达情况。结果:用不同浓度的CDCA(25μmol/L、50μmol/L、75μmol/L)分别作用HepG2细胞6h、12h、24h、48h后,HL的mRNA和蛋白质水平呈时间和剂量依赖性下调。结论:FXR激动剂可抑制肝脂酶的表达。     

雌激素受体β基因CA重复序列多态性与绝经后骨质疏松症的关联性研究

绝经后骨质疏松症(PMO)是一种多基因调控的遗传性疾病。雌激素受体β亚型基因是骨质疏松症的重要侯选基因。此文采用病例对照设计(78名股骨颈PMO病人和122名对照以及108名腰椎PMO病人和92名对照)研究中国人(汉族)雌激素受体β基因(ESR2)第5内含子CA重复序列多态性与PMO的相关性。以CA重复序列平均数22次为界将重复序列基因分为短基因(<22)和长基因(≥22),分别以S和L表示。股骨颈及腰椎(L2-4)部位,病例组中LL基因型和L等位基因者频率显著高于对照组(P<0.01),SL、LL及SL LL基因型者较SS基因型者患PMO风险显著增高(P<0.05);调整年龄、绝经时间、绝经年龄及体质指数后,Logistic回归分析显示ESR2(CA)n多态性仍然与股骨颈(OR4.923,95%CI1.986～12.203,P=0.001)及L2-4(OR2.267,95%CI1.121～4.598,P=0.023)PMO显著相关。结果显示:ESR2基因CA重复序列多态性与股骨颈和L2-4部位PMO独立关联,L等位基因显性影响PMO的发病风险。     

功能性新型冠状病毒RBD结构域在毕赤酵母表面的展示*

目的:设计并构建新型冠状病毒(SARS-CoV-2)受体结合结构域(receptor binding domain,RBD)在毕赤酵母表面的展示体系,并对表面展示的RBD进行功能性评价,从而为以RBD为靶点的高通量药物筛选平台奠定基础。方法:将四种锚定分子与新冠病毒RBD融合,电转化至毕赤酵母中;通过细胞免疫荧光分析,筛选能够成功展示RBD的锚定系统;进一步分析其与血管紧张素转化酶2(angiotensin-converting enzyme 2,ACE2)受体的亲和力,证明展示在细胞表面RBD分子的功能。结果:仅Sed1p锚定分子能够有效呈递RBD至毕赤酵母细胞表面,展示效率约为70%;亲和力分析结果表明,ACE2受体和表面展示RBD的亲和力(K_D = 30.42 nmol/L)与溶液中RBD的亲和力(K_D = 16.00 nmol/L)较为接近。结论:这一体系能够在毕赤酵母表面高效地展示具有生物学功能的RBD,可用于抗新冠病毒RBD药物的高通量筛选和评价。     

革兰氏阴性菌TonB依赖性受体的功能与结构研究进展*

为维持生长所需,革兰氏阴性菌需要从外界摄取多种营养物质。分子量小于600 Da的分子可以通过自由扩散的方式通过革兰氏阴性菌的外膜,而大分子物质则需要特殊的转运系统才能将其转运至革兰氏阴性菌的胞内。革兰氏阴性菌对大分子营养物质的识别和转运主要由TonB依赖性受体负责完成。所有革兰氏阴性菌中均有TonB依赖性受体的存在,然而不同种类的革兰氏阴性菌拥有TonB依赖性受体的数量不同且功能各异。最近研究表明,TonB依赖性受体不仅参与了铁、血红素、锰、锌、镍、维生素、碳水化合物等多种营养物质的摄取,而且参与了蛋白酶的分泌。为对TonB依赖性受体提供更为深入和系统的理解,详细介绍了目前已知的TonB依赖性受体的功能及结构,以期为更进一步探知TonB依赖性受体未知功能提供可参考依据。     

工程化外泌体介导巨噬细胞清除肿瘤外泌体*

目的:通过膜表面修饰改造技术构建工程化外泌体(engineered exosomes,enExos),并以此介导巨噬细胞特异性清除膜表面富含表皮生长因子受体(epidermal growth factor receptor,EGFR)的肿瘤外泌体。方法:利用表面展示技术获得膜表面展示趋化因子(chemokine 8,CXCL8)的外泌体,同时在其磷脂双分子层上修饰EGFR核酸适配体制备工程化外泌体;纳米颗粒跟踪和纳米粒度电位分析enExos的尺寸、电位;CCK-8试剂盒检测细胞活力;透射电子显微镜观察enExos与高表达EGFR的肿瘤外泌体的特异性结合;荧光成像技术及流式细胞术分析探究enExos靶向趋化巨噬细胞吞噬高表达EGFR的肿瘤外泌体。结果:成功构建膜表面展示EGFR与CXCL8的工程化外泌体,enExos可以特异性识别并捕获高表达EGFR的肿瘤外泌体,同时利用其趋化因子CXCL8特异性靶向巨噬细胞膜表面趋化因子受体CXCR1/CXCR2,刺激巨噬细胞对肿瘤外泌体的捕获及清除。结论:工程化外泌体促进了特定肿瘤外泌体的清除,为后续深入研究工程化外泌体抑制癌症转移的作用奠定基础,并期望为癌症转移治疗提供新的研究方向。     

马来酸曲美布汀联合莫沙必利对功能性消化不良患者胃电图参数、肠道菌群和血清NPSR-1、CGRP、MTL、GAS的影响

摘要 目的：观察马来酸曲美布汀联合莫沙必利对功能性消化不良（FD）患者胃电图参数、肠道菌群和血清神经肽S受体-1（NPSR-1）、降钙素基因相关肽（CGRP）、胃动素(MTL)、胃泌素(GAS)的影响。方法：选取2019年8月~2021年6月期间我院收治的FD患者100例,根据信封抽签法分为对照组（莫沙必利治疗,n=50）和观察组（马来酸曲美布汀联合莫沙必利治疗,n=50）。对比两组疗效、胃电图参数、肠道菌群变化情况和血清NPSR-1、CGRP、MTL、GAS水平,记录两组不良反应发生率。结果：观察组的临床总有效率高于对照组（P<0.05）。治疗后,两组空腹及餐后正常慢波百分比均较治疗前升高,胃电频率、胃电紊乱节律百分比均较治疗前下降,且观察组的变化幅度更大（P<0.05）。治疗后,两组肠杆菌、肠球菌、酵母菌数量较治疗前下降,且观察组的下降幅度更明显（P<0.05）。治疗后,两组血清CGRP水平较治疗前下降,NPSR-1、MTL、GAS水平较治疗前升高,且观察组的变化幅度更大（P<0.05）。两组不良反应发生率组间对比差异无统计学意义（P>0.05）。结论：马来酸曲美布汀联合莫沙必利治疗FD患者,可有效改善胃电图参数和肠道菌群分布,调节其血清NPSR-1、CGRP、MTL、GAS水平,安全有效。     

陈氏心衰方联合β-受体阻滞药治疗缺血性心肌病心衰疗效及对心功能、6 min步行试验影响

摘要 目的：探讨陈氏心衰方及β-受体阻滞药治疗缺血性心肌病心衰疗效及对心功能、6 min步行试验影响。方法：选取我院2022.4-2022.5所收治的70例缺血性心肌病心衰患者按照随机数字表法分为心衰方组和对照组,各35例,其中对照组采取常规治疗+β-受体阻滞药治疗,心衰方组对照组治疗基础上,加用陈氏心衰方治疗,对比两种治疗方案疗效及对心功能、6 min步行试验影响。结果：心衰方组的治疗有效率（97.1 %）显著高于对照组（82.9 %）（P＜0.05）;治疗后,两组心功能均显著改善,而与对照组相比,心衰方组LVEDD和LVESD显著降低,LVEF显著增加（P＜0.05）;治疗前6 min步行试验结果对比无统计学差异（P＞0.05）,治疗后两组患者6 min步行试验结果明显长于治疗前,且心衰方组治疗后也显著长于对照组（P＜0.05）;治疗前两组患者BNP水平、中医证候评分、生活质量评分差异无统计学意义（P＞0.05）,治疗后两组患者的BNP水平、中医证候评分、生活质量评分均明显降低,且心衰方组也显著低于对照组（P＜0.05）。结论：陈氏心衰方及β-受体阻滞药治疗缺血性心肌病心衰疗效显著,可改善患者的心功能,疗效优于单一应用β-受体阻滞药,更适用于缺血性心肌病心衰的治疗,临床上积极及推广应用功能联合用药治疗方式。