应激状态下人群心脏储备的调研

目的:研究应激状态下人群心脏储备动用情况。方法:选择运动员81名进行心音图运动试验,分别记录其静息状态和运动后即刻的第1心音幅值与第2心音幅值之比(S1/S2)、舒张期与收缩期时限之比(D/S)和心率(HR);选择心血管病人以及对照组-健康人群各25名,健康孕妇320名(孕周≥28周)以及对照组-健康育龄妇女100名,记录静息状态下的S1/S2、D/S和HR。结果:运动员静息状态和运动后即刻S1/S2和HR升高,D/S降低,有显著性差异(P<0.01);心血管病人相对于健康人S1/S2和HR较高,D/S较低(P均<0.01)相对于健康育龄妇女,孕妇S1/S2和HR较高,D/S较低(P均<0.01)。应激状态下D/S比值会减低,S1/S2升高,HR越快。结论:应激导致心脏负担加重、会调用心力储备和心率储备,心脏功能上调。     

应激条件下人群心脏储备动用趋势的特征研究

目的:探讨应激条件下人群心脏储备动用趋势的复杂度特征。方法:应用运动心力监测仪采集运动员(A组,n=15)和普通大学生(B组,n=15)静息和不同负荷运动后即刻的心音信号,分析心动周期里心音信号的样本熵。结果:静息状态、1 750J、3 500 J、5 250 J、7 000 J 4种不同负荷后即刻运动员和普通大学生的心动周期心音样本熵值均呈下降趋势,且运动员样本熵值均低于普通大学生的。静息时两人群样本熵值未显统计学差异,而运动负荷后即刻表现出显著性差异(P0.05)。静息状态、1 750J、3 500 J、5 250 J、7 000 J 4种不同负荷后即刻运动员心率均低于普通大学生心率,而且普通大学生和运动员的心音样本熵与心率和运动负荷均呈显著(P0.05)相关关系,相关系数分别为-0.671和-0.745。结论:样本熵可以作为评估应激条件下人群心脏储备动用趋势的指标,且能区分普通大学生与运动员的心脏储备动用趋势差异。     

负重越野训练对战士心功能的影响

目的：通过对某军事院校战士在负重越野训练前后的心音图、心电图、血压检测,评估战士心功能变化,为训练提供参考依据。方法：选取59名（男41,女18）,年龄17~23岁,分别检测两次越野（男5 km,负重11 kg,时限25 min;女1.5 km,无负重,时限10 min）前、运动后即刻及48 h后进行心音图和心电图。结果：两次运动后即刻较运动前心率、第1心音幅值/第2心音幅值比值显著升高（P<0.01）;舒张期/收缩期时限比值下降（P<0.01）;收缩压略有上升,舒张压有所下降,未出现运动高血压。运动48 h后,各指标均基本恢复至运动前水平。心电图无异常。本次研究观察到13人（男8,女5）在运动前未屏气状态下出现第1、2心音幅值倒置现象。结论：该强度越野训练对心功能无损伤,是一种安全的高强度训练方法。     

运动员心功能评估新方法和新指标的研究

目的：探讨无创检测和评估心功能的新指标和新方法。方法：随机抽取81名体育系学生（买验组,n=81）和41名普通系学生（对照组,n=41）,完成规定运动量的台阶运动后,通过采集心音信号,进行了心率,D／S比值以及S1／S2比值的对照研究。结果：在静息状态下,体育系学生的心率为66．2±8．7,D／S比值为2．04±0．33;晋通系学生的心率为70．8±8．0,D／S比值为1．82±0．27;在全运动量下,体育系学生的S1／S2比值为7．34±4．04;普通系学生的S1／S2比值为5．22±2．38。,结论：体育系学生比普通系学生具有较高水平的心脏储备：该方法可用来评估运动员与一般人的心脏储备,为运动员选拔以及一般人体质评估提供一种客观量化的新指标。     

用心脏舒张期与收缩期时限比值评估青少年心脏功能

目的：观察青少年在安静状态及最大运动量状态下心脏舒张期时限与收缩期时限比值（D/S）的变化情况,并运用该指标对青少年心脏功能的评估进行探讨。方法：选取重庆市主城区中学309名（男159名,女150名）青少年为研究对象,受试者完成最大运动量的台阶运动,在安静状态和运动后即刻进行D/S比值的测试。根据安静状态D/S值的大小范围将受试者心脏功能分级为优（ D/S≥2）、良（1.5≤D/S<2）、中（1≤D/S<1.5）、差（D/S<1）。结果：安静状态下男生心脏功能评定为优、良、中、差的占比分别为： 7.5%、49.1%、 40.9%、2.5%;女生分别为： 5.3%、48.0%; 44.7%、2.0%。运动后男、女青少年D/S值都明显下降,但心脏功能评定等级高的受试者运动后D/S仍高于等级低的受试者。结论：本次研究的青少年虽有过半心脏功能处于健康状态,但处于亚健康状态的比例较高,有少部分学生心脏功能较差,其心脏健康应得到高度重视;心脏功能等级越高的学生运动后心脏供血时间越长,其心脏功能更好。应用D/S值可以有效评估青少年心脏供血时限的相关情况;对青少年心脏功能进行分级可以针对不同分级群体制定有针对性的运动训练,同时预防心脏安全事故的出现。该评估方法操作简单、客观,可作为一种日常的心脏监测手段在学校普及。     

运动后心力及心率同时遥测的心力恢复趋势与心率恢复趋势的对比研究

为了更加全面地研究和评估心肌的变时性和变力性,研制了能够在运动场地同时采集心力和心率的心音信号遥测系统。采集了50名体育系学生和30名其他系学生在完成规定运动量的登梯运动后,5min内连续变化的心音信号。对采集的数据经过3次样条插值、均匀采样和小波变换滤波后,得到了平滑的心力恢复趋势曲线和心率恢复趋势曲线。统计分析表明,大负荷运动量下的心脏储备主要来自于心力储备而不是心率储备(P<0.001),和其他系学生相比,体育系学生具有的高水平心功能不仅在于具有更大的心力储备指数(P<0.001),而且还在于具有更快的心力恢复速度(P<0.001)。同时检测心力恢复趋势与心率恢复趋势会有益于全面评估心脏功能。     

运动负荷对青年学生和运动员心脏功能的影响

用无创法(阻抗法)测量了40名青年学生和40名运动员在两种运动负荷(50W和150W)运动前、运动后即刻和恢复时程的收缩时间间期(STI)和心率(HR)。在静态时,“运动员组”的心率较缓(P<0.01)、QS_1较长(P<0.05)、PEP/LVET比值较大(P<0.05和P<0.01)、LVETc较短(P<0.001)。运动后即刻,“学生组”和“运动员组”都表现为QS_z、LVET、PEP、IVCT、QS_1缩短、PEP/LVET比值减小、心率增速和LVETc延长。但“运动员组”QS_2、LYET的缩短和心率增速的程度较少,而PEP/LVET比值的减小和LVETc延长的程度较大。除PEP/LVET比值外,其余各项指标的恢复速度均与负荷量有关。“运动员组”的恢复速度较快,尤其在150W时更为明显。本文指出:1)用阻抗法测算动态下的STI更为实用;2)系统训练可提高心脏活动的潜力,改善泵功能,促进心脏活动的调节速度。     

CKMM基因A/G多态与新疆维吾尔族运动能力的相关性

目的:研究新疆维吾尔族114名运动员(速度力量型项目43人,耐力型项目35人,足球36人)和441名普通人肌型肌酸激酶(CKMM)基因A/G多态性与运动能力相关性。方法:聚合酶链式反应-限制性片段长度多态性(PCR-RFLP)法。结果:1维吾尔族普通人群CKMM基因A/G多态性频率(AA、AG、GG)分别为0.497、0.392、0.111,经检验符合H-W平衡(x~2=2.72,P0.05),具有群体代表性;2速度力量型项目运动员3种基因型频率分别0.442、0.302、0.256,GG基因型和G等位基因频率显著高于对照组,两组差异有显著性(P0.05,df=2);3耐力型项目运动员3种基因型频率分别为0.571、0.400、0.029,A等位基因频率高于对照组,但差异没有显著性(P0.05,df=2);4足球运动员3种基因型频率分别为0.472、0.361、0.167,G等位基因频率高于耐力组低于速度力量组,与对照组相比亦无显著性差异(P0.05,df=2)。结论:CKMM基因A/G多态性与维吾尔族速度力量素质呈显著相关,GG基因型和G等位基因可用于速度力量运动员选材的一个辅助因子,但没有发现A/G多态性与耐力素质和足球成绩存在显著相关性。     

8周有氧水上划艇训练对赛艇运动员某些儿茶酚胺和心率变异性指标的影响

目的:探讨有氧渐增负荷量水上划艇训练对赛艇运动员某些血液儿茶酚胺和心率变异性指标的影响。方法:对8名男子公开级赛艇运动员进行持续8周的中等强度有氧渐增负荷量水上划艇训练,运动员每周一至周五上下午和周六上午进行训练,此后至周末恢复休息,每个半天训练120min,第一周的水上划艇负荷量为180km,此后每周递增5km。运动员在训练前1周、训练第4周以及训练第8周结束后的次周一清晨6:00进行安静状态下短时程5min的心率变异性测试,并在心率变异性测试结束即刻进行安静状态下的肘静脉血采集,用于儿茶酚胺指标的检测。结果:与训练前相比,运动员经过有氧渐增负荷量水上划艇训练第4周和第8周后,血浆儿茶酚胺E、NE和DA水平均显著性降低(P<0.05);恢复期心率变异性TP、HF和LF水平,在训练第4周时有所降低,在训练第8周时有所升高,而VLF则在训练第4周和第8周时均有所降低,但这些变化没有统计学意义(P>0.05)。结论:运动员经过8周的有氧渐增负荷量水上划艇训练后,运动员安静下迷走神经系统对心血管系统的调节作用得到增强,交感迷走神经的综合调节作用得到提高,自主神经系统的功能状况得到改善。     

能量消耗C指标在评价乒乓球运动员多球练习中能量消耗的应用*

目的:研究周期类运动能量消耗^C指标在评价乒乓球多球练习中能量消耗应用的可行性。方法:11名某大学代表队的乒乓球运动员(18±1 yrs, 177±2 cm, 71±3 kg,运动水平≥二级)自愿参加了1次跑台递增负荷测试和2次(正手和反手)发球机多球递增频率测试(3 min × 6级,频率为35~85 stroke·min^-1)。用便携式气体代谢仪和心率监测仪检测3次测试的呼吸气体和心率,计算每种频率下每次击球所消耗的能量;采集运动前后的耳血进行血乳酸分析。结果:乒乓球前冲弧圈多球练习的能量消耗^C随击球频率的增加而下降(P＜0.05)。6种击球频率下,正手前冲弧圈的能量消耗^C都高于反手,且差异在35、45、55、65和85 stroke·min^-1时显著(P＜0.05)。能量消耗^C与频率的关系公式分别为y=166.4x^-0.731(R²=0.9731)和y=33.21x^-0.392(R²=0.8423),其中y为能量消耗^C(单位为J·stroke^-1·kg^-1),x为击球频率(单位为stroke·min^-1)。结论:周期类运动项目的能量消耗^C可应用于评价乒乓球运动员单一技术动作多球练习的能量消耗,反映乒乓球运动员在不同击球频率下的击球效率。     

Cell Wall,Cytoskeleton, and Cell Expansion in Higher Plants

To accommodate two seemingly contradictory biological roles in plant physiology, providing both the rigid structural support of plant cells and the adjustable elasticity needed for cell expansion, the composition of the plant cell wall has evolved to become an intricate network of cellulosic, hemicellulosic, and pectic polysaccharides and protein. Due to its complexity, many aspects of the cell wall influence plant cell expansion, and many new and insightful observations and technologies are forthcoming. The biosynthesis of cell wall polymers and the roles of the variety of proteins involved in polysaccharide synthesis continue to be characterized. The interactions within the cell wall polymer network and the modification of these interactions provide insight into how the plant cell wall provides its dual function. The complex cell wall architecture is controlled and organized in part by the dynamic intracellular cytoskeleton and by diverse trafficking pathways of the cell wall polymers and cell wall-related machinery. Meanwhile, the cell wall is continually influenced by hormonal and integrity sensing stimuli that are perceived by the cell. These many processes cooperate to construct, maintain, and manipulate the intricate plant cell wall--an essential structure for the sustaining of the plant stature, growth, and life.     

Dissecting the Heat Stress Response in Chlamydomonas by Pharmaceutical and RNAi Approaches Reveals Conserved and Novel Aspects

To study how conserved fundamental concepts of the heat stress response （HSR） are in photosynthetic eukaryotes, we applied pharmaceutical and antisense/amiRNA approaches to the unicellular green alga Chlamydomonas reinhardtii. The Chlamydomonas HSR appears to be triggered by the accumulation of unfolded proteins, as it was induced at ambient temperatures by feeding cells with the arginine analog canavanine. The protein kinase inhibitor staurosporine strongly retarded the HSR, demonstrating the importance of phosphorylation during activation of the HSR also in Chlamydomonas. While the removal of extracellular calcium by the application of EGTA and BAPTA inhibited the HSR in moss and higher plants, only the addition of BAPTA, but not of EGTA, retarded the HSR and impaired thermotoler- ance in Chlamydomonas. The addition of cycloheximide, an inhibitor of cytosolic protein synthesis, abolished the attenu- ation of the HSR, indicating that protein synthesis is necessary to restore proteostasis. HSP90 inhibitors induced a stress response when added at ambient conditions and retarded attenuation of the HSR at elevated temperatures. In addition, we detected a direct physical interaction between cytosolic HSP90A/HSP70A and heat shock factor 1, but surprisingly this interaction persisted after the onset of stress. Finally, the expression of antisense constructs targeting chloroplast HSP70B resulted in a delay of the cell＇s entire HSR, thus suggesting the existence of a retrograde stress signaling cascade that is desensitized in HSP7OB-antisense strains.     

Redox Regulation of Arabidopsis Mitochondrial Citrate Synthase

Citrate synthase has a key role in the tricarboxylic （TCA） cycle of mitochondria of all organisms, as it cata- lyzes the first committed step which is the fusion of a carbon-carbon bond between oxaloacetate and acetyl CoA. The regulation of TCA cycle function is especially important in plants, since mitochondrial activities have to be coordinated with photosynthesis. The posttranslational regulation of TCA cycle activity in plants is thus far almost entirely unexplored. Although several TCA cycle enzymes have been identified as thioredoxin targets in vitro, the existence of any thioredoxin-dependent regulation as known for the Calvin cycle, yet remains to be demonstrated. Here we have investigated the redox regulation of the Arabidopsis citrate synthase enzyme by site-directed mutagenesis of its six cysteine residues. Our results indicate that oxidation inhibits the enzyme activity by the formation of mixed disulfides, as the partially oxidized citrate synthase enzyme forms large redox-dependent aggregates. Furthermore, we were able to demonstrate that thioredoxin can cleave diverse intraas well as intermolecular disulfide bridges, which strongly enhances the activity of the enzyme. Activity measurements with the cysteine variants of the enzyme revealed important cysteine residues affecting total enzyme activity as well as the redox sensitivity of the enzyme.     

Organelle pH in the Arabidopsis Endomembrane System

The pH of intracellular compartments is essential for the viability of cells. Despite its relevance, little is known about the pH of these compartments. To measure pH in vivo, we have first generated two pH sensors by combining the improved-solubility feature of solubility-modified green fluorescent protein （GFP） （smGFP） with the pH-sensing capabil- ity of the pHluorins and codon optimized for expression in Arabidopsis. PEpHluorin （plant-solubility-modified ecliptic pHluorin） gradually loses fluorescence as pH is lowered with fluorescence vanishing at pH 6.2 and PRpHluorin （plant- solubility-modified ratiomatric pHluorin）, a dual-excitation sensor, allowing for precise measurements. Compartment- specific sensors were generated by further fusing specific sorting signals to PEpHluorin and PRpHluorin. Our results show that the pH of cytosol and nucleus is similar （pH 7.3 and 7.2）, while peroxisomes, mitochondrial matrix, and plastidial stroma have alkaline pH. Compartments of the secretory pathway reveal a gradual acidification, spanning from pH 7.1 in the endoplasmic reticulum （ER） to pH 5.2 in the vacuole. Surprisingly, pH in the trans-Golgi network （TGN） and mul- tivesicular body （MVB） is, with pH 6.3 and 6.2, quite similar. The inhibition of vacuolar-type H＋-ATPase （V-ATPase） with concanamycin A （ConcA） caused drastic increase in pH in TGN and vacuole. Overall, the PEpHluorin and PRpHluorin are excellent pH sensors for visualization and quantification of pH in vivo, respectively.     

How does the host-specialized aphid deal with food deficiency？

Aphis gossypii Glover shows obvious host specialization, with cucurbit- and cotton-specialized biotypes or host races in many regions. Because its annual natal hostcrops senesce earlier the cucurbit-specialized biotype may suffer food deficiency. The method this biotype uses to overcome this challenge is still poorly understood. In orderto understand the potential of the cucurbit-specialized biotype aphids in host shift and usage, the performance of this biotype on cotton （Gossypium hirsutum）, a common butpoor quality host plant, was explored in this study. The cucurbit-specialized aphids could establish populations on cotton only when these plants had at least nine leaves, and subsequent populations developed rather slowly. The presence of whitefly populations on cotton improved the success rate of cucurbit-specialized aphids. The cucurbit-specialized aphidswere mainly distributed on the older leaves of cotton, with only a few settling on the upper leaves. The cucurbit-specialized aphids reared on cotton for 40, 54 and 61 days stillmaintained strong preference for their natal host plant, cucumber （Cucumis sativus）, rather than cotton, and their net reproductive rates and intrinsic rates of natural increase weredramatically lower when they were transferred onto new six-leaf cotton plants or detached leaves. Therefore, we concluded that the cucurbit-specialized aphids have the potentialto utilize mature or whitefly-stressed cotton plants, but that this feeding experience on cotton did not alter their specialization for cucurbits. Some cotton plants could act as atemporary host for the cucurbit-specialized aphids to overcome food deficiency arising from senescing cucurbits.     

Plastid Signals and the Bundle Sheath： Mesophyll Development in Reticulate Mutants

The development of a plant leaf is a meticulously orchestrated sequence of events producing a complex organ comprising diverse cell types. The reticulate class of leaf variegation mutants displays contrasting pigmentation between veins and interveinal regions due to specific aberrations in the development of mesophyll cells. Thus, the reticulate mutants offer a potent tool to investigate cell-type-specific developmental processes. The discovery that most mutants are affected in plastid-localized, metabolic pathways that are strongly expressed in vasculature-associated tis- sues implicates a crucial role for the bundle sheath and their chloroplasts in proper development of the mesophyll cells. Here, we review the reticulate mutants and their phenotypic characteristics, with a focus on those in Arabidopsis thali- ana. Two alternative models have been put forward to explain the relationship between plastid metabolism and meso- phyll cell development, which we call here the supply and the signaling hypotheses. We critically assess these proposed models and discuss their implications for leaf development and bundle sheath function in C3 species. The characteriza- tion of the reticulate mutants supports the significance of plastid retrograde signaling in cell development and highlights the significance of the bundle sheath in C3 photosynthesis.     

Knights in Action： Lectin Receptor-Like Kinases in Plant Development and Stress Responses

The Receptor-Like Kinase （RLK） is a vast protein family with over 600 genes in Arabidopsis and 1100 in rice. The Lectin RLK （LecRLK） family is believed to play crucial roles in saccharide signaling as well as stress perception. All the LecRLKs possess three domains： an N-terminal lectin domain, an intermediate transmembrane domain, and a C-terminal kinase domain. On the basis of lectin domain variability, LecRLKs have been subgrouped into three subclasses： L-, G-, and C-type LecRLKs. While the previous studies on LecRLKs were dedicated to classification, comparative structural analysis and expression analysis by promoter-based studies, most of the recent studies on LecRLKs have laid special emphasis on the potential of this gene family in regulating biotic/abiotic stress and developmental pathways in plants, thus mak- ing the prospects of studying the LecRLK-mediated regulatory mechanism exceptionally promising. In this review, we have described in detail the LecRLK gene family with respect to a historical, evolutionary, and structural point of view. Furthermore, we have laid emphasis on the LecRLKs roles in development, stress conditions, and hormonal response. We have also discussed the exciting research prospects offered by the current knowledge on the LecRLK gene family. The multitude of the LecRLK gene family members and their functional diversity mark these genes as both interesting and worthy candidates for further analysis, especially in the field of crop improvement.     

Aphis （Hemiptera： Aphididae） species groups found in the Midwestern United States and their contribution to the phylogenetic knowledge of the genus

A phylogeny of the genus Aphis Linnaeus, 1 758 was built primarily from specimens collected in the Midwest of the United States. A data matrix was constructedwith 68 species and 41 morphological characters with respective character states of alate and apterous viviparous females. Dendrogram topologies of analyses performed usingUPGMA （Unweighted Pair Group Method with Arithmetic Mean）, Maximum Parsimony and Bayesian analysis of Cytochrome Oxidase I, Elongation Factor 1-α and primary endosymbiont Buchnera aphidicola 16S sequences were not congruent. Bayesian analysis strongly supported most terminal nodes of the phylogenetic trees. The phylogeny wasstrongly supported by EFI-α, and analysis of COl and EFI-α molecular data combined with morphological characters. It was not supported by single analysis of COI or Buch-hera aphidicola 16S. Results from the Bayesian phylogeny show 4 main species groups： asclepiadis,fabae, gossypii, and middletonii. Results place Aphis and species of the generaProtaphis Bōrner, 1952, Toxoptera Koch, 1856 and Xerobion Nevsky, 1928 in a monophyletic clade. Morphological characters support this monophyly as well. The phylogenyshows that the monophyletic clade of the North American middletonii species group belong to the genus Protaphis： P. debilicornis （Gillette ＆ Palmer, 1929）, comb. nov., P. echinaceae（Lagos and Voegtlin, 2009）, comb. nov., and P. middletonii （Thomas, 1879）. The genus Toxoptera should be considered a subgenus of Aphis （stat. nov.）. The analysis also indicatesthat the current genus Iowana Frison, 1954 should be considered a subgenus of Aphis （stat. nov.）.     

Open and Closed： The Roles of Linker Histones in Plants and Animals

Histones package DNA in all eukaryotes and play key roles in regulating gene expression. Approximately 150 base pairs of DNA wraps around an octamer of core histones to form the nucleosome, the basic unit of chromatin. Linker histones compact chromatin further by binding to and neutralizing the charge of the DNA between nucleosomes. It is well established that chromatin packing is regulated by a complex pattern of posttranslational modifications （PTMs） to core histones, but linker histone function is less well understood. In this review, we describe the current understand- ing of the many roles that linker histones play in cellular processes, including gene regulation, cell division, and devel- opment, while putting the linker histone in the context of other nuclear proteins. Although intriguing roles for plant linker histones are beginning to emerge, much of our current understanding comes from work in animal systems. Many unanswered questions remain and additional work is required to fully elucidate the complex processes mediated by linker histones in plants.