Polar tube proteins of microsporidia of the family encephalitozoonidae

Encephalitozoonidae are microsporidia associated with human infections including hepatitis, encephalitis, conjunctivitis, and disseminated disease. Microsporidia produce a small resistant spore containing a polar tube which serves as a unique vehicle of infection. Polar tube proteins (PTPs) from Encephalitozoon hellem. Encephalitozoon (Septata) intestinalis, and Encephalitozoon cuniculi were purified to homogeneity by HPLC. By SDS-PAGE, the Mr of E. hellem PTP was 55 kDa, while the Mr of E. intestinalis and E. cuniculi PTP was 45 kDa. Polyclonal rabbit antiserum to these purified PTPs localized to polar filaments by immunogold electron microscopy and immunofluorescence, and demonstrated cross-reactivity by both immunoblotting and immunogold electron microscopy. These PTPs have similar solubility properties, hydrophobicity, and proline content to a 43-kDa PTP we have previously purified from Glugea americanus, a fish microsporidium. As the polar tube is critical in the transmission of this organism, further study of PTPs may lead to the development of new therapeutic strategies and diagnostic tests.     

生长素极性运输研究进展

高等植物的生长发育受激素的广泛调控,其中生长素的作用尤为独特,因为生长素在植物组织内的浓度梯度是由其极性运输维持的,而正是激素在植物组织的相对含量决定了该组织的发育命运。高等植物体内存在可运输的化学信使的概念首先由Ｄａｒｗｉｎ父子提出。通过对金丝鸟木亡草（Ｐｈａｌａｒｉｓｃａ ｎａｒｉｅｎｓｉｓ）幼苗的向光性的研究,他们认为植物的向光性受到一种可运输的物质的调控［1］。后来发现这一物质是生长素,在自然界中主要存在的形式是ＩＡＡ。到本世纪 30年代,禾谷类植物中的生长素的极性运输得到证实,后来发现所有…     

生长素极性运输研究进展

Recent advances in dissecting polar auxin transport, i.e., the physiological characteristics and regulation of polar auxin transport, the chemiosmotic hypothesis for polar auxin transport, and the role of polar auxin transport in plant growth and development were reviewed. The authors here focus on the progress of new supports-isolation and function analysis of the genes encoding putative auxin carriers, for the old model of polar auxin transport.     

棉花li突变体生长素极性运输的减弱

陆地棉(Gossypium hirsutum L.)li突变体叶片卷曲,植株扭曲,种子表皮毛明显偏短。通过扫描电子显微镜(SEM)观察发现,li突变体的纤维发育在起始期与野生型植株并无明显差异,但在伸长期开始后,如开花后3d(3 day post anthesis,DPA),纤维伸长受阻;li突变体茎的形成层和韧皮部分化发育不完全,生长素由顶端向基部的极性运输能力下降,仅为野生型植株的大约三分之一。推测棉花li突变体包括纤维发育不良在内的多效性异常表型,与其生长素极性运输能力的下降有关。     

植物生长素的极性运输载体研究进展

生长素极性运输在植物生长发育中起重要的调控作用.植物细胞间的生长素极性运输主要通过生长素运输载体进行调控.该文对近年来有关生长素极性运输载体,包括输入载体AUX/LAX、输出载体PIN、尤其是新近发现的兼有输入和输出载体功能的MDR/PGP等蛋白家族,以及生长素极性运输中PIN与MDR/PGP蛋白间相互作用关系进行综述.     

Development of the Polar Filament-Polaroplast Complex in a Microsporidian Parasite*

SYNOPSIS. The development of the polar filament in a microsporidian parasite was studied in the electron microscope. The polar filament is a peculiar and complex organelle with intricate anatomical relationships to other structures in the mature spore. The characteristic ultrastructure of the formative and mature stages of the polar filament made it possible to trace its development and study the interactions among various organelles during its formation. In sporoblasts the polar filament develops sequentially from 3 different regions. The base of the filament appears first and is derived from a dense body. The anterior part of the filament is formed from electron dense material located in the perinuclear cisterna and in agranular endoplasmic reticulum. The base and the anterior part of the filament move toward each other and fuse. Subsequently, the posterior part of the filament develops from the posterior part of the Golgi complex. The polar sac and the polaroplast surrounding the anterior segment of the filament are formed from the anterior region of the Golgi complex.     

Various Polar Tripeptides as Asymmetric Organocatalyst in Direct Aldol Reactions in Aqueous Media

A series of tripeptide organocatalysts containing a secondary amine group and two amino acids with polar side chain units were developed and evaluated in the direct asymmetric intermolecular aldol reaction of 4‐nitrobenzaldehyde and cyclohexanone. The effectiveness of short polar peptides as asymmetric catalysts in aldol reactions to attain high yields of enantio‐ and diastereoselective isomers were investigated. In a comparison, glutamic acid and histidine produced higher % ee and yields when they were applied as the second amino acid in short trimeric peptides. These short polar peptides were found to be efficient organocatalysts for the asymmetric aldol addition reaction in aqueous media. Chirality 25:726–734, 2013. © 2013 Wiley Periodicals, Inc     

Polar group conformation of 1,2-di-O-alkylglycerophosphocholines in the absence and presence of ions

The conformation of the glycerophosphocholine (GPC) group of various 1,2-di-O-alkyl and 1,2-diacylglycerophosphocholines forming small micelles or single-bilayer vesicles in H₂O has been studed by NMR in the absence and presence of lanthanide ions. In the absence of lanthanides the motionally averaged polar group conformation of 1,2-di-O-alkylglycerophosphocholine (dialkyl-GPC) is similar to that of the diacyl compound. The replacement of the ester linkages in diacyl phosphatidylcholine by ether bonds has therefore no significant effect on the conformation and segmental motion of the glycerophosphocholine group. This conformation is found to be independent of the state of aggregation, i.e., the main features are the same below and above the critical micellar concentration (CMC). The determining factor must therefore be the intramolecular energetics. Within the experimental accuracy the conformation of dialkyl-GPC in the presence of lanthanide ions is also the same as that of the corresponding diacyl compound. Furthermore, in the presence of lanthanides the polar group conformation of dialkyl-GPC is the same within experimental accuracy in small micelles and single bilayer vesicles. The conformational change induced by lanthanides leads to a reorientation of the OPN dipole. In the presence of lanthanides the OPN dipole increases its angle of tilt with respect to the bilayer plane from about 0° (coplanar orientation) to an average inclinication of about 45°. This gives rise to a more extended disposition of the polar group with respect to the bilayer normal.     

Rearrangement of the Hydrogen-Bonded Network of the Clathrate Hydrates Encaging Polar Guest

Abstract

Rearrangement process of the hydrogen-bonded network of clathrate hydrate of the polar guest ethylamine is examined by the molecular dynamics simulation. The hydrogen-bonded network rearrangements with reorientation of water or migration of water are observed in the 10 ns trajectories and analyzed in term of a representative connectivity pattern of a time zone longer than a time scale of vibrational motion of molecules. The most frequent rearrangement is the reorientation of single water molecule rotating 180° around its twofold axis in the network unlike Bjerrum's picture of molecular rotation in ice. Migration of water in the host lattice rarely occurs and very long time (several hundred pico second) is required to complete the rearrangement process since cooperative reorientation of many neighboring water is necessarily accompanied. The correlation of reorientational motion of water appears to decay not with the Debye type but rather with a power-law behavior.     

Polar lipid composition of leaves from nine typical alpine species

The fatty acids and polar lipid compositions of leaves from nine alpine species were almost identical to that of plants growing in habitats with little seasonal variation in temperature. Furthermore each polar lipid had about the same fatty acid composition in all plant species studied. It is suggested that neither the relative proportions of different lipid classes nor the degree of saturation of individual classes are directly implicated in the adaptation of plant tissues to different climates.     

Identification of a Microsporidian Polar Tube Protein Reactive Monoclonal Antibody

ABSTRACT. The microsporidia are characterized by spores containing a single polar tube that coils around the sporoplasm. When triggered by appropriate stimuli, the polar tube rapidly discharges out of the spore forming a hollow tube. The sporoplasm passes out of the spore through this tube serving as a unique vehicle of infection. Due to the unusual functional and solubility properties of the polar tube, the proteins comprising it are likely to be members of a protein family with a highly conserved amino acid composition among the various microsporidia. Polar tube proteins were separated from the majority of other proteins in glass bead disrupted spores of Glugea americanus using sequential 1% sodium dodecyl sulfate (SDS) and 9M urea extractions. The resultant spore pellet demonstrated broken, empty spore coats and numerous polar tubes in straight and twisted formations by negative stain transmission electron microscopy. After subsequent incubation of the pellet with 2% dithiothreitol (DTT), empty spore coats were still observed but the polar tubes were no longer present in the pellet. The DTT supernatant demonstrated four major protein bands by SDS-PAGE: 23, 27, 34 and 43 kDa. Monoclonal antibodies were produced to these proteins using Hunter's Titermax adjuvant. Mab 3C8.23.1 which cross-reacted with a 43-kDa antigen by immunoblot analyis, demonstrated strong reactivity with the polar tube of G. americanus spores by immunogold electron microscopy. This antibody will be useful in further characterization of polar tube proteins and may lead to novel diagnostic and therapeutic reagents.     

植物生长素极性运输调控机理的研究进展

生长素极性运输特异地调控植物器官发生、发育和向性反应等生理过程。本文综述和分析了生长素极性运输的调控机制。分子遗传和生理学研究证明极性运输这一过程是由生长素输入载体和输出载体活性控制的。小G蛋白ARF附属蛋白GEF和GAP分别调控输出载体（PINI）和输入载体（AUX1）的定位和活性。并影响高尔基体等介导的细胞囊泡运输系统,小G蛋白ROP也参与输出载体PIN2活性的调节。本文基于作者的研究工作提出小G蛋白在调控生长素极性运输中的可能作用模式。     

Polar bodies--more a lack of understanding than a lack of respect

Polar bodies are as diverse as the organisms that produce them. Although in many animals these cells often die following meiotic maturation of the oocyte, in other organisms they are an essential and diverse part of embryonic development. Here we highlight some of this diversity and summarize the evolutionary basis for their utility.     

Characterization of Polar and Non‐Polar Compounds of House Edible Bird's Nest (EBN) from Johor,Malaysia

This work investigated the polar (PC: protein, amino acid and metabolite) and non‐polar (NPC: fatty acid) compounds and bioactivity characteristics of the EBN harvested from the state of Johor in Malaysia. The electrophoretic gels exhibited 15 protein bands (16–173 kD) with unique protein profile. Amino acids analysis by AccQ?Tag method revealed 18 types of amino acids in EBN. Metabolite profiling was performed using High‐Performance Liquid Chromatography coupled with Quadrupole Time‐of‐Flight Mass Spectrometer (HPLC‐QTOF/MS) technique and a total of 54 compounds belonging to different groups were detected and identified. These findings help to uncover the relation of therapeutic activity of EBN. The EBN was further extracted with AcOEt and BuOH. The AcOEt extract was fractionated into three fractions (F₁?F₃), and the high triglyceride content in F₂ was verified by gC‐FID. The three groups of fatty acids discovered in EBN are 48.43 % of poly‐unsaturated (PUFA), 25.35 % of saturated fatty acids (SFA) and 24.74 % of mono‐unsaturated fat (MUFA). This is the first time to report results ofEBN, BuOH, and AcOEt extracts and of fraction F₂ (TEBN) on their analysis for their antioxidant activities by DPPH, ABTS and catalase assay and for their paraoxonase and anti‐tyrosinase activities. The results showed that TEBN exhibited the significant bioactivity in all assays. These findings suggest that TEBN is a good source for natural bioactive compounds in promoting body vigor. Current work widened the content of EBN especially on the triglyceride and also marked the content of specific location (Johor, Malaysia) of EBN origin.     

生长素极性运输在水稻根发育中的作用

生长素极性运输(PAT)在植物生长发育尤其是极性发育和模式建成中起重要作用.采用2种PAT抑制剂TIBA(2,3,5-triiodobenzoic acid)和HFCA(9-hydroxyfluorene-9-carboxylic acid)处理水稻(Oryza sativa L. cv.Zhonghua)幼苗,结果表明:PAT影响水稻根发育包括主根的伸长、侧根的起始和伸长以及不定根的发育.PAT的抑制导致主根变短、侧根和不定根数目减少.外源附加生长素(NAA)可以部分恢复不定根的形成但不能恢复侧根的形成,表明在侧根和不定根的形成上可能具有不同的机制.切片结果表明,30μmol/TIBA处理后并不完全抑制侧根原基的形成,进一步研究表明生长素由胚芽鞘向基部的运输在水稻不定根的起始和伸长中起关键作用.     

Polar lipid composition of chloroplast thylakoids isolated from leaves grown under different lighting conditions

The polar acyl lipid composition was determined for samples of chloroplast thylakoids isolated from Pisum sativum plants grown at light intensities of 50 and 300 E·m^-2·s^-1 and from Aesculus hippocastanum leaves taken from shade or sun environments. Lighting conditions had no major effect on lipid class composition except for a small increase in the amount of monogalactosyldiacylglycerol relative to other lipids in low compared with high light and shade compared with sun conditions. The thylakoids from low light and shade environments also had, relative to those from high light and sun conditions, a substantial decrease in the level of trans-hexadecenoic acid in phosphatidyglycerol. In parallel with this there were lower lipid to chlorophyll ratios, higher overall fatty acid unsaturation, lower chlorophyll a to b ratios and increased relative levels of light harvesting chlorophyll a/b polypeptides as expected for an increase in the degree of thylakoid appression. With this in mind, our results on lipid class composition and content of trans-hexadecenoic acid are discussed in the context of the lateral distribution of lipids within the plane of membrane.Abbreviations DGDG digalactosyldiacylglycerol - EDTA ethylenediaminetetraacetic acid - HEPES N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid - LHC light harvesting chlorophyll a/b - MGDG monogalactosyldiacylglycerol - MPL minor phospholipids - PS1 photosystem one - PS2 photosystem two - SDS sodium dodecyl sulphate - SL sulphoquinovosyldiacylglycerol     

An Ultrastructural Study of the Extruded Polar Tube of Anncaliia algerae (Microsporidia)

All microsporidia share a unique, extracellular spore stage, containing the infective sporoplasm and the apparatus for initiating infection. The polar filament/polar tube when exiting the spore transports the sporoplasm through it into a host cell. While universal, these structures and processes have been enigmatic. This study utilized several types of microscopy, describing and extending our understanding of these structures and their functions. Cryogenically preserved polar tubes vary in diameter from 155 to over 200 nm, noticeably larger than fixed‐sectioned or negatively stained samples. The polar tube surface is pleated and covered with fine fibrillar material that projects from the surface and is organized in clusters or tufts. These fibrils may be the sites of glycoproteins providing protection and aiding infectivity. The polar tube surface is ridged with 5–6 nm spacing between ridges, enabling the polar tube to rapidly increase its diameter to facilitate the passage of the various cargo including cylinders, sacs or vesicles filled with particulate material and the intact sporoplasm containing a diplokaryon. The lumen of the tube is lined with a membrane that facilitates this passage. Careful examination of the terminus of the tube indicates that it has a closed tip where the membranes for the terminal sac are located.     

第二极体排出时间早晚与胚胎发育潜能相关性的研究

目的探讨第二极体排出时间早晚与胚胎质量及发育潜能之间的关系。方法以本生殖医学中心2009年6月-8月IVF—ET周期患者受精卵子为研究对象,共计1170枚卵子。以受精5h为时间界限将受精胚胎分为第二极体正常排出组（正常组）和延迟排出组（延迟组）。分别观察两组卵子正常／异常受精率（2PN率,1PN和3PN率）和优质胚胎率;同时统计阳性妊娠结局所移植胚胎中,正常组和延迟组的胚胎比例各占多少。采用卡方检验对数据进行统计学处理。结果①两组正常受精卵数目之间以及异常受精卵数目之间均有显著性差异（P〈0．05）;两组总受精卵数目之间有非常显著差异（P〈0．001）。②两组的优质胚胎率之间显著性差异（P〈0．05）。③统计阳性妊娠结局所移植的97个胚胎中,来自于正常组的胚胎有92个（94．9％）,仅5个是来自于延迟组（5．1％）。结论受精5h内排出第二极体的卵子其总受精率、正常受精率以及所发育的胚胎质量均显著高于第二极体出现晚的卵子,而且有着较高的胚胎植入率。对受精5h的卵子进行第二极体观察有助于早期预测患者本次IVF-ET周期胚胎的发育潜能以及妊娠结局;还可以作为决定是否行早补救ICSI的判定指标之一。