Plasma membrane-anchored fluorescent tracker based on boron-dipyrromethene

The construction of a stable-membrane tracker has significant implications for the visualization of the membrane in live cells.However,most current plasma trackers are not suitable for tracking plasma membranes for a long time due to their limited retention time.Herein,Mem580-F-Sulfo is designed to target and anchor cell membranes and therefore track cell membranes for a longer time.This tracker is composed of a lipophilic boron-dipyrromethene(BODIPY)derivative and a hydrophilic zwitterion to form an amphiphilic structure,which enables its targeting ability toward cell membranes.Moreover,a reactive ester group is included to bind with proteins through covalent bonds in cell membranes nonspecifically,which extends retention time in cell membranes.Mem580-F-Sulfo shows intense brightness(94600),with a high molar absorption coefficient of up to about 100000 L·mol^(-1)·cm^(-1)and a fluorescence quantum yield of up to 0.97.It shows fast cell membrane targeting ability and long retention up to 90 min.In brief,this work has not only developed a tracker with good cell membrane targetability but also provided a new strategy for improving the targeting stability of cell membranes.

Water relations and an expression analysis of plasma membrane intrinsic proteins in sensitive and tolerant rice during chilling and recovery

A symptom of chilling injury is development of water deficit in shoots, resulting from an imbalance of water transport and transpiration. In this work, two rice varieties （Oryza sativa L. var. Wasetoitsu and Somewake） seedlings were chilled at 7 ℃, followed by recovery at 28 ℃. Based on the growth phenotype and electrolyte leakage tests, Somewake was shown to be a chilling-tolerant variety, and Wasetoitsu a chilling-sensitive one. The chilling stress reduced markedly the relative water content （RWC） of leaves, accumulative transpiration and osmotic root hydraulic conductivity （Lp） in both varieties. But when retumed to 28 ℃, the water relation balance of Somewake recovered better. The mRNA expression profile of all the 11 plasma membrane intrinsic proteins （PIPs）, a subgroup of aquaporins, was subsequently determined by real-time reverse transcription （RT）-PCR with TaqMan-minor grove binder （MGB） probes derived from rice var. Nipponbare during chilling treatment and recovery. Most of the PIP genes was down-regulated at the low temperature, and recovered at the warm temperature. The relative expression of some PIPs in both Somewake and Wasetoitsu decreased in parallel during the chilling. However during the recovery, the relative expression of OsPIP1;1, OsPIP2;1, OsPIP2;7 in shoots and OsPIP1：1, OsPIP2：1 in roots were significantly higher in Somewake than Wasetoitsu. This supports the role of PIPs in re-establishing water balance after chilling conditions. We discuss the diversified roles played by members of the aquaporin PIP subfamily in plant chilling tolerance depending on aquaporin isoforms, plant tissue and the stage of chilling duration.

Generation and Identification of Monoclonal Antibody Against Porcine Adipocyte Plasma Membrane Proteins

Production of monoclonal antibody against porcine adipocyte plasma membrane proteins to explore a new way of controlling body fat deposition and improving carcass quality is discussed in this article. Membrane proteins of pig adipocyte plasma membrane proteins were extracted with the help of sucrose density gradient centrifugation, and two kinds of proteins were obtained. The monoclonal antibody （designated 3B2 and 3F3） of IgG1 and IgG2b subclass against adipocyte membrane proteins were produced by immunization, with adipocyte membrane proteins as an antigen, and its titer was 1：105 detected by enzyme-linked immunoadsorbent assay （ELISA）. The cell strains were identified by analyzing the number of chromosomes, the heat stability, the acid and alkali, the types and subtypes of immnoglobulin, and its peculiarities and affinities. Through identification, the chromosome number of hybridoma cell strains was from 80 to 100 and the strains formed good hybridomas colonies. The strains＇ affinity constants were 4.63 × 10^9 and 3.75 × 10^9 （mol L^-1）-1, respectively. At the same time, the McAb secreted was stable to environmental factors, such as, temperature, acid, alkali and so on. The monoclonal antibodies had been obtained and their specificity to porcine adipocyte plasma membrane proteins had been identified.

Secondary Structure Changes and Thermal Stability of Plasma Membrane Proteins of Wheat Roots in Heat Stress

The wheat roots membrane separates the cell from the environment around it and encloses the cell contents. The pro-tein secondary structure and thermal stability of the plasma membrane of wheat root have been characterized in D2O buffer from 20°C to 90°C by Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Quantitative analysis of the amide I band (1700 - 1600 cm–1) showed that the plasma membrane proteins contains 41% α-helix, 16% β-sheet, 18% turn, and 25% disorder structures at 20°C. At elevated temperatures from 25°C up to 90°C, the α-helix and the β-sheet structure unfold into turns and the disorder structure, with a major conformational transition occurring at 50°C. There is a rapid decline in H+-ATPase activity of plasma membrane from 35°C to 55°C and it remain very low level H+-ATPase activity of PM from 55°C to 90°C. Therefore the protein conformational transition was one of reasons of loses H+-ATPase activity of plasma membrane.

Preliminary study on plasma membrane fluidity of Psychrophilic Yeast Rhodotorula sp.NJ298 in low temperature

The ability of cell to modulate the fluidity of plasma membrane was crucial to the survival of microorganism at low temperature.Plasma membrane proteins,fatty acids and carotenoids profiles of Antarctic psychrophilc yeast Rhodotorula sp.NJ298 were investigated at-3 ℃,0 ℃ and 8 ℃.The results showed that plasma membrane protein content was greater at-3 ℃ than that at 8 ℃,and a unique membrane polypeptide composition with an apparent molecular mass of 94.7 kDa was newly synthesized with SDS-PAGE analysis;GC analysis showed that the main changes of fatty acids were the percentage of unsaturated fatty acids(C18:1 and C18:2) and shorter chain saturated fatty acid(C10:0) increased along with the decrease of the culture temperature from 8 ℃ to-3 ℃;HPLC analysis indicated that astaxanthin was the major functional carotenoids of the plasma membrane,percentage of which increased from 54.6±1.5% at 8 ℃ to 81.9±2.1% at-3 ℃.However the fluidity of plasma membrane which was determined by measuring fluorescence anisotropy was similar at-3 ℃,0 ℃ and 8 ℃.Hence these changes in plasma membrane’s characteristics were involved in the cellular cold-adaptation by which NJ298 could maintain normal plasma membrane fluidity at near-freezing temperature.

Original article Activated changes of platelet ultra microstructure and plasma granule membrane protein 140 in patients with non-small cell lung cancer

Background Non-small cell lung cancer （NSCLC） is the leading cause of cancer mortality worldwide. Platelet activation may play an important role in pathologic progress in lung cancer. In this study, we aimed to clarify the influence of activated platelets on lung cancer generation and growth, and the relationship among these functional and ultrastructural chanqes of platelets and the severity of pathoeenetic condition in these Datients with NSCLC.Methods One hundred and thirty-six cases of patients with pathologically confirmed NSCLC were included in this study. Fifty-four healthy people were enrolled as controls. The change of ultra microstructure and activity of blood platelets were observed under the transmission and scanning electron microscope. Simultaneous determination of plasma granule membrane protein 140 （GMP-140） was made.Results Transmission electron microscopy showed remarkable changes of ultra microstructure of platelets in patients with NSCLC, including swelling, increase of α-granules, vesicles, and glycogenosome. Scanning electron microscopy showed many more surface processes and wrinkles on platelets in patients with NSCLC. The reference plasma levels of GMP-140 of healthy controls were （18.2±2.7） μg/L. The plasma levels of GMP-140 in patients with NSCLC were （47.8±12.3） μg/L, which were much higher than those of the controls. There was a medium positive correlation between plasma levels of GMP-140 and amount of α-granules （r=0.514, P 〈0.01） and a high positive correlation between plasma levels of GMP-140 and area of platelet （r=0.84, P 〈0.01） in patients with NSCLC. The Kaplan-Meier survival curve analysis showed significant shift to the left in patients with NSCLC whose a-granules per platelet were 19 or more compared to those 18 or less （Log rank statistic, X^2= 17.38, P〈0.01）.Conclusions There are significant activated changes of ultra microstructure and increased activity of blood platelets in patients with NSCLC. These activated platelets may play an important role in the generation and growth of lung cancer. These changes can be used as a diagnostic index of severity, progression, and prognosis of NSCLC.

Effects of Garlicin on Unstable Angina Pectoris and Its Relationship with Blood Lipid and Granule Membrane Protein-140

Objective: To observe the clinical effects of Garlicin on unstable angina pectoris (UAP) and explore how the Garlicin's effects vary among syndromes as defined by traditional Chinese medicine (TCM).Methods: Fifty-five patients with UAP were randomly divided into the Garlicin group (34 patients) and the control group (21 patients). Each patient was classified according to TCM Syndrome Differentiation as having Cold Syndrome type, Heat Syndrome type, severe blood stasis (SBS) type, and mild blood stasis (MBS) type of UAP. Garlicin 60 mg or nitroglycerin 5 mg was given to the two groups respectively by intravenous drip for 10days as one therapeutic course. The curative effect was evaluated by symptomatic changes and electrocardiogram. The effective rates as well as indexes such as blood lipid, lipoprotein, apolipoprotein, and granule membrane protein-140 (GMP-140) were compared between groups and types. Results: Garlicin and nitroglycerin group did not differ significantly in effective rate, while that of Garlicin group was higher for the Cold Syndrome type than that of Heat Syndrome type (P < 0. 01 ). The high density lipoprotein/low density lipoprotein ratio and apolipoprotein A- I level rose markedly in the former type (P < 0. 05), while an opposite trend was seen in the Heat Syndrome type. Garlicin was more effective in the SBS type than that in the MBS type, and it markedly decreased GMP-140 in the MBS type. Conclusions: Garlicin is effective in UAP, especially the Cold Syndrome and SBS types. Its mechanism may involve improving blood lipid levels and inhibiting platelet activation.

Intracellular Transport of HIV-1 Matrix Protein Associated with Viral RNA

HIV-1 matrix protein (MA) is a multifunctional structural protein localized on N terminus of Gag precursor p55. MA participates in HIV-1 assembly as membranotropic part of Gag precursor as well as an individual protein spliced from Gag early in infection. MA is found in the nuclei of infected cells and in plasma membrane, the site of virus assembly, in association with viral genome RNA. MA mutated variant M4 which contains two changed amino acids in N-terminal regions is also associated with viral RNA, but it is localized in the nuclear and cytoskeleton fractions but not in the plasma membrane suggesting that the mutant is deprived of membranotropic signal and “sticks” in the nuclei an d cytoskeleton, its previous location sites. These data allow suggesting that MA involved into transmission of viral RNA is transported to plasma membrane by cytoskeleton.

Activation effect of extracellular calmodulin on heterotrimeric G protein in pollen plasma membrane

IN recent years, calmodulin （CaM）, an important Ca2+ receptor and constituent of cellular signal transduction systems, has been found extracellularly. We have verified that CaM is presented extracellularly in all of plant species we have examined. In addition, we have reported that extracellular CaM has some biological significance, such as stimulation of cell proliferation, cell wall regeneration, initiation of pollen germination and tube growth and inducement of rbcS gene expression. The role of heterotrimeric G proteins in pollen germination, tube growth and signal transduction of extracellular CaM has been examined in Lily pollen, and two kinds of antibodies against animal Gzα internal sequence and N-terminal

Advances in Molecular Biology for Plasma Membrane Intrinsic Proteins(PIPs):A Review

Water is an important component in plant cells with plant aquaporin being the major protein for water transport in and between plant cells.As a subfamily of plant aquaporins,the plasma membrane intrinsic proteins（PIPs） located in the plasma membrane are classic,high water,selective channel proteins.This paper focuses on recent advances in the molecular biology of PIPs concerning structural characteristics,biological function,and a regulation mechanism.PIPs possess two highly conserved domains:GGGANXXXXGY and TGI/TNPARSL/FGAAI/VI/VFWF/YN.PIPs can also be divided into two phylogenetic subgroups named PIP1 and PIP2.PIP1 possesses longer N terminal sequences and shorter C terminal sequences than PIP2 with conserved amino acid sequences respectively.Studies of transgenic plants and expression in Xenopus oocytes cells indicate that PIPs not only may facilitate transport of water and small neutral solutes like CO2 and glycerin,but they also possess many physiological functions. The functions of plant aquaporins are regulated by many factors including post-translational modification,heteromerization,pH value,and divalent cations.These results indicated that PIPs act as a pivotal role in water and small neutral solutes transport in plants.

A Protein Extracted from Mouse Sperm That Plays an Important Role in Fertilization

A membrane protein was isolated from mouse sperm heads that had undergone acrosomal reaction induced by C2+ ionophore, A 23187, which, with a molecular weight of 77.6 kd, shows capability to block egg-sperm fusion. As revealed by analysis usintg isotopic markers, this protein is one of the chief membrane proteins of inner acrosomal membrane or the outer membrane of equatorial segment and Post-acrosomal region; treatment of mouse sperms with 0.6 μg/ml of the Purified protein for 30 minutes reduced the sperm-egg fusion index by 51%.The above results led us to the conclusion that the protein is an active participant in sperm-egg fusion. The possible existence of sperm receptor on egg plasma membrane was discussed.

油莎豆块茎高水平表达CePIP1;1基因的克隆与分析

油莎豆隶属于禾本目莎草科,是一种在块茎中高水平积累油脂的新型草本油料作物。与其他块根块茎类作物类似,未成熟油莎豆块茎的含水量高达85%,因此,水分平衡对于块茎的发育至关重要。质膜内在蛋白(PIP)是一类定位在细胞膜上具有高效水分转运活性的水通道蛋白,包含PIP1和PIP2两个亚类。本研究基于块茎蛋白组中鉴定到的一个PIP蛋白,采用RT-PCR技术对其编码基因进行克隆,并在此基础上分析其基因结构、序列特征、进化关系、表达特性及蛋白亚细胞定位。结果表明:CePIP1;1含有3个内含子,编码区全长867 bp,编码288个氨基酸,理论分子量为30.76 kDa,等电点为8.82,不稳定系数为32.95,总平均疏水指数为0.384,脂肪族指数为95.28,属于稳定的碱性疏水型蛋白;该蛋白含有保守的MIP结构域,其中包括6个跨膜螺旋、2个半螺旋以及位于半螺旋顶端的NPA基序。序列比对和进化分析显示,CePIP1;1与水稻的PIP1亚类聚在一起,相比于菠菜PIP2;1拥有延伸的N端和较短的C端,符合PIP1亚类的基本特征。在烟草叶片中的亚细胞定位分析显示,CePIP1;1定位在细胞膜,这与生物信息学预测结果一致。表达分析显示,CePIP1;1在分析的所有组织中均高水平表达,属于组成型表达基因,其在块茎的发育过程中呈现先升后降的钟形趋势,与水分含量趋势基本一致。这些结果为下一步的功能分析及油莎豆遗传改良奠定坚实的基础。

明睛颗粒联合雷珠单抗对湿性年龄相关性黄斑变性纤维血管膜纤维化相关蛋白表达的影响

[目的]观察明睛颗粒联合雷珠单抗玻璃体腔注射对实验性湿性年龄相关性黄斑变性(nAMD)纤维血管膜以及纤维化相关蛋白表达的影响,阐释明睛颗粒治疗nAMD的作用机制,为临床上中药联合抗血管内皮生长因子(VEGF)药物治疗提供理论依据。[方法]应用两阶段激光光凝的方法建立实验性nAMD纤维血管膜模型,将造模成功后的BN大鼠随机分为3组:模型组、抗VEGF组、明睛颗粒(MJKL)+抗VEGF组。模型组:予蒸馏水灌胃;抗VEGF组:予玻璃体腔注射雷珠单抗注射液;MJKL+抗VEGF组:予玻璃体腔注射雷珠单抗注射液,同时予明睛颗粒灌胃。10只BN大鼠不造模,常规饲养作为正常对照组。造模40 d后,采用眼底照相(FP)、眼底血管荧光造影(FFA)、光学相干断层扫描(OCT)、视网膜色素上皮(RPE)-脉络膜-巩膜铺片观察眼底病变形态、病变渗出面积及MD值;组织病理学观察视网膜结构的改变,免疫荧光法检测Collagen-1,Fibronectin,α-SMA,TGF-β1的表达及分布,qRT-PCR法检测Collagen-1mRNA,FibronectinmRNA,α-SMAmRNA和TGF-β1 mRNA的相对表达量。[结果]两阶段激光造模后40d建立纤维血管膜模型;抗VEGF组在病变渗出面积、光密度值(MD)值、病变高度均较模型组显著降低(P<0.05),病变面积及视网膜结构损伤程度显著降低;而MJKL+抗VEGF组较抗VEGF组在病变渗出的MD值、病变高度更加降低(P<0.05),病变面积及视网膜结构损伤程度也明显降低。Collagen-1,Fibronectin,α-SMA,TGF-β1的荧光强度中模型组均较正常组明显升高(P<0.05),抗VEGF组均较模型组明显降低(P<0.05);MJKL+抗VEGF组中Collagen-1,Fibronectin,TGF-β1的荧光强度较抗VEGF组明显降低(P<0.05)。Collagen-1mRNA,FibronectinmRNA,α-SMAmRNA和TGF-β1 mRNA的相对表达量中,模型组均较正常组明显升高(P<0.05),抗VEGF组均较模型组明显降低(P<0.05),MJKL+抗VEGF组均较抗VEGF组明显降低(P<0.05)。[结论]明睛颗粒联合抗VEGF药物可以通过降低Collagen-1,Fibronectin,α-SMA,TGF-β1蛋白的表达,从而较单一应用抗VEGF药物可以更好地抑制实验性nAMD纤维血管膜的生长。

油莎豆CePIP2;1的克隆、亚细胞定位与表达分析

油莎豆是一种在块茎中高水平积累油脂的草本油料作物,其未成熟块茎的含水量高达85%,水分平衡对于块茎的发育与代谢至关重要。质膜内在蛋白(PIP)是介导细胞间水分跨膜运输的主要通道。本研究报道1个块茎高水平表达的PIP基因CePIP2;1,该基因含有3个内含子,预测编码288个氨基酸(aa),其理论分子量(MW)为30.34 kDa,等电点(pI)为8.60,总平均疏水指数(GRAVY)为0.529,不稳定系数(Ⅱ)为29.60,属于典型的稳定、碱性、疏水型蛋白。CePIP2;1含有保守的MIP结构域,ar/R选择性滤器为F-H-T-R,Froger位点为Q-S-A-F-W,符合高水分转运活性PIP的特征。进化分析显示,CePIP2;1与OsPIP2;1、OsPIP2;2和OsPIP2;3聚在一起,序列相似性分别为91.72%、90.31%和84.98%,支持其归为PIP2亚类。亚细胞定位分析显示,CePIP2;1定位在烟草叶片的细胞膜。进一步的表达分析显示,虽然CePIP2;1为主要的块茎表达PIP基因,但其在叶片、叶鞘、匍匐茎和根等组织中的表达丰度更高,最高的为叶片,而在芽尖中的表达丰度与块茎相当;在块茎的4个典型发育时期(S_(1)~S_(4))中,CePIP2;1基因呈现先升后降的钟形趋势,表达丰度最高的是S_(2)。这些结果为解析油莎豆的水分平衡机制奠定基础。

Ca^(2+)-dependent TaCCD1 cooperates with TaSAUR215 to enhance plasma membrane H^(+)-ATPase activity and alkali stress tolerance by inhibiting PP2C-mediated dephosphorylation of TaHA2 in wheat

Alkali stress is a major constraint for crop production in many regions of saline-alkali land.However,little is known about the mechanisms through which wheat responds to alkali stress.In this study,we identified a calcium ion-binding protein from wheat,TaCCD1,which is critical for regulating the plasma membrane(PM)H^(+)-ATPase-mediated alkali stress response.PM H+-ATPase activity is closely related to alkali tolerance in the wheat variety Shanrong 4(SR4).We found that two D-clade type 2C protein phosphatases,TaPP2C.D1 and TaPP2C.D8(TaPP2C.D1/8),negatively modulate alkali stress tolerance by dephosphorylating the penultimate threonine residue(Thr926)of TaHA2 and thereby inhibiting PM H+-ATPase activity.Alkali stress induces the expression of TaCCD1 in SR4,and TaCCD1 interacts with TaSAUR215,an early auxin-responsive protein.These responses are both dependent on calcium signaling triggered by alkali stress.TaCCD1 enhances the inhibitory effect of TaSAUR215 on TaPP2C.D1/8 activity,thereby promoting the activity of the PM H^(+)-ATPase TaHA2 and alkali stress tolerance in wheat.Functional and genetic analyses verified the effects of these genes in response to alkali stress,indicating that TaPP2C.D1/8 function downstream of TaSAUR215 and TaCCD1.Collectively,this study uncovers a new signaling pathway that regulates wheat responses to alkali stress,in which Ca^(2+)-dependent TaCCD1 cooperates with TaSAUR215 to enhance PM H+-ATPase activity and alkali stress tolerance by inhibiting TaPP2C.D1/8-mediated dephosphorylation of PM H+-ATPase TaHA2 in wheat.

Topography and functional information of plasma membrane

By using atomic force microscope (AFM), the topography and function of the plasmalemma surface of the isolated protoplasts from winter wheat mesophyll cells were observed, and compared with dead protoplasts induced by dehydrating stress. The observational results revealed that the plasma membrane of living protoplasts was in a state of polarization. Lipid layers of different cells and membrane areas exhibited distinct active states. The surfaces of plasma membranes were unequal, and were characterized of regionalisation. In addition, lattice structures were visualized in some regions of the membrane surface. These typical structures were assumed to be lipid molecular complexes, which were measured to be 15.8±0.09 nm in diameter and 1.9±0.3 nm in height. Both two-dimensional and three-dimensional imaging showed that the plasmalemma surfaces of winter wheat protoplasts were covered with numerous protruding particles. In order to determine the chemical nature of the protruding particles, living protoplasts were treated by proteolytic enzyme. Under the effect of enzyme, large particles became relatively looser, resulting that their width was increased and their height decreased. The results demonstrated that these particles were likely to be of protein nature. These protein particles at plasmalemma surface were different in size and unequal in distribution. The diameter of large protein particles ranged from 200 to 440 nm, with a central micropore, and the apparent height of them was found to vary from 12 to 40 nm. The diameter of mid-sized protein particles was between 40―60 nm, and a range of 1.8―5 nm was given for the apparent height of them. As for small protein particles, obtained values were 12―40 nm for their diameter and 0.7―2.2 nm for height. Some invaginated pits were also observed at the plasma membrane. They were formed by the endocytosis of protoplast. Distribution density of them at plasmalemma was about 16 pits per 15 μm2. According to their size, we classified the invaginated pits into two types―larger pits measuring 139 nm in diameter and 7.2 nm in depth, and smaller pits measuring 96 nm in diameter and 2.3 nm in depth. On dehydration-induced dead pro-toplasts, the degree of polarization of plasma membranes decreased. Lipid molecular layers appeared relatively smooth, and the quantity of integral proteins reduced a lot. Invaginated pits were still de-tectable at the membrane surface, but due to dehydration-induced protoplast contraction, the orifice diameter of pits reduced, and their depth increased. Larger pits averagely measuring 47.4 nm in di-ameter and 31.9 nm in depth, and smaller pits measuring 26.5 nm in diameter and 43 nm in depth at average. The measured thickness of plasma membranes of mesophyll cells from winter wheat examined by AFM was 6.6―9.8 nm, thicker in regions covered with proteins.

橡胶树水通道蛋白HbPIP1;4的亚细胞定位与多聚化分析

质膜内在蛋白(PIP)隶属于水通道蛋白家族,其以细胞膜定位并具有高效的水分转运活性而著称。PIP高度保守,主要包含PIP1和PIP2两个亚类。天然橡胶是重要的工业原料和战略物资,其主要来源为巴西橡胶树。作为橡胶合成和储藏的特异组织,乳管与邻近的薄壁细胞之间缺乏胞间连丝,其水分平衡主要由PIP介导。通过前期研究,团队鉴定到一个PIP1亚类成员HbPIP1;4,该基因在乳管中高水平表达,然而,其在蟾蜍卵母细胞中异源表达却无水分转运活性,推测因不能有效定位到细胞膜所致。为探讨HbPIP1;4在植物体内的功能部位及作用模式,本研究构建了其亚细胞定位和双分子荧光互补(BiFC)载体。通过利用农杆菌介导法瞬时转化烟草叶片,再用激光共聚焦显微镜进行观察,发现荧光信号出现在细胞膜,这与生物信息学预测的细胞膜定位结果一致。BiFC实验进一步证实HbPIP1;4定位在细胞膜,结果同时显示,HbPIP1;4可形成同源多聚体,这与3D结构预测结果一致。上述结果为深入揭示乳管的水分平衡机制奠定了坚实的基础。但HbPIP1;4的异源互作模式还有待进一步研究。

血清Adropin、TLR4、GMP-140水平与不稳定型心绞痛患者冠状动脉病变程度的相关性

目的:分析血清能量平衡相关蛋白(Adropin)、Toll样受体4(TLR4)、血小板颗粒膜蛋白140(GMP-140)水平与不稳定型心绞痛患者冠状动脉病变程度的相关性。方法:回顾性分析2021—2023年该院收治的107例不稳定型心绞痛患者的临床资料,设为研究组,另选取同期107名健康体检者作为对照组。比较两组及不同冠状动脉病变程度、病变血管数不稳定型心绞痛患者血清Adropin、TLR4、GMP-140水平,采用Spearman相关性分析Adropin、TLR4、GMP-140水平与冠状动脉病变程度的相关性。结果:研究组血清Adropin水平低于对照组,TLR4、GMP-140水平均高于对照组,差异有统计学意义(P<0.05);重度病变患者血清Adropin水平低于轻中度病变患者,TLR4、GMP-140水平均高于轻中度病变患者,差异有统计学意义(P<0.05);不同冠状动脉病变血管数患者血清Adropin水平比较:三支病变患者<双支病变患者<单支病变患者;不同冠状动脉病变血管数患者TLR4、GMP-140水平比较:三支病变患者>双支病变患者>单支病变患者,差异均有统计学意义(P<0.05);经Spearman相关性分析结果显示,血清Adropin水平与冠状动脉病变程度、病变血管数均呈负相关(r<0,P<0.05);血清TLR4、GMP-140水平与冠状动脉病变程度、病变血管数均呈正相关(r>0,P<0.05)。结论:血清Adropin、TLR4、GMP-140水平与不稳定型心绞痛患者冠脉病变程度存在相关性。

Identification and characterization of plasma membrane aquaporins isolated from fiber cells of Calotropis procera

Calotropis procera, commonly known as "milkweed", possesses long seed trichomes for seed dispersal and has the ability to survive under harsh conditions such as drought and salinity. Aquaporins are water channel proteins expressed in all land plants, divided into five subfamilies plasma membrane intrinsic proteins (PIPs), tonoplast intrinsic proteins (TIPs), NOD26-like proteins (NIPs), small basic intrinsic proteins (SIPs), and the unfamiliar X intrinsic proteins (XIPs). PIPs constitute the largest group of water channel proteins that are involved in different developmental and regulatory mechanisms including water permeability, cell elongation, and stomata opening. Aquaporins are also involved in abiotic stress tolerance and cell expansion mechanisms, but their role in seed trichomes (fiber cells) has never been investigated. A large number of clones isolated from C. procera fiber cDNA library showed sequence homology to PIPs. Both expressed sequence tags (ESTs) and real-time polymerase chain reaction (PCR) studies revealed that the transcript abundance of this gene family in fiber cells of C. procera is greater than that of cotton. Full-length cDNAs of CpPIP1 and CpPIP2 were isolated from C. procera fiber cDNA library and used for constructing plant expression vectors under constitutive (2×35S) and trichome-specific (GhLTP3) promoters. Transgenic tobacco plants were developed via Agrobacterium-mediated transformation. The phenotypic characteristics of the plants were observed after confirming the integration of transgene in plants. It was observed that CpPIP2 expression cassette under 2×35S and GhLTP3 promoter enhanced the numbers of stem and leave trichomes. However, 2×35S::CpPIP2 has a more amplified effect on trichome density and length than GhLTP3::CpPIP2 and other PIP constructs. These findings imply the role of C. procera PIP aquaporins in fiber cell elongation. The PIPs-derived cell expansion mechanism may be exploited through transgenic approaches for improvement of fiber staple length in cotton and boosting of defense against sucking insects by enhancing plant pubescence.

Enquiry into the Topology of Plasma Membrane- Localized PIN Auxin Transport Components

Auxin directs plant ontogenesis via differential accumulation within tissues depending largely on the activity of PIN proteins that mediate auxin efflux from cells and its directional cell-to-cell transport. Regard- less of the developmental importance of PINs, the structure of these transporters is poorly characterized. Here, we present experimental data concerning protein topology of plasma membrane-localized PINs. Utilizing approaches based on pH-dependent quenching of fluorescent reporters combined with immuno- localization techniques, we mapped the membrane topology of PINs and further cross-validated our results using available topology modeling software. We delineated the topology of PIN1 with two transmembrane （TM） bundles of five m-helices linked by a large intracellular loop and a C-terminus positioned outside the cytoplasm. Using constraints derived from our experimental data, we also provide an updated position of helical regions generating a verisimilitude model of PIN1. Since the canonical long PINs show a high degree of conservation in TM domains and auxin transport capacity has been demonstrated for Arabidopsis representatives of this group, this empirically enhanced topological model of PIN1 will be an important starting point for further studies on PIN structure-function relationships. In addition, we have established protocols that can be used to probe the topology of other plasma membrane proteins in plants.