原矛头蝮蛇毒对小鼠器官形态的影响

目的:观察原矛头蝮(P.mucrosquamatus)蛇毒对小鼠脏器形态结构的影响,从组织学角度探讨该蛇毒的致病机理。方法:用原矛头蝮攻击小鼠,待小鼠死亡后,立即进行解剖,观察心脏和大血管内部血栓形成情况。取心脏、血管、周围神经、肾脏、肝脏、脾脏和肺,观察外形,并进行石蜡切片,H.E染色观察。用健康小鼠相同器官为对照,比较二者的差异。结果:被原矛头蝮攻击致死小鼠的心脏、肝脏和肺发生了显著收缩;心腔和血管腔被血栓堵塞;在心脏、肝脏和肾脏组织血管中观察到了血栓;脾脏中白细胞显著增多;肺泡收缩,细支气管严重收缩致管腔堵塞;股动脉血管内膜发生了脱落;在股神经中发生了脱髓鞘现象。结论:急性凝血和窒息是导致小鼠死亡的重要原因;原矛头蝮蛇毒兼具血循毒和神经毒的特征;原矛头蝮蛇毒可导致多种脏器内部结构发生改变。     

Crowding,Entropic Forces,and Confinement: Crucial Factors for Structures and Functions in the Cell Nucleus

The view of the cell nucleus as a crowded system of colloid particles and that chromosomes are giant self-avoiding polymers is stimulating rapid advances in our understanding of its structure and activities, thanks to concepts and experimental methods from colloid, polymer, soft matter, and nano sciences and to increased computational power for simulating macromolecules and polymers. This review summarizes current understanding of some characteristics of the molecular environment in the nucleus, of how intranuclear compartments are formed, and of how the genome is highly but precisely compacted, and underlines the crucial, subtle, and sometimes unintuitive effects on structures and reactions of entropic forces caused by the high concentration of macromolecules in the nucleus.     

Cell Wall and Morphological Changes Induced by Temperature Shift in Bacillus subtilis Cell Wall Mutants

Bacillus subtilis RUB1012 and RUB1013 have the following phenotype when grown at 45 degrees C: no growth on tryptose blood agar base, growth as clumps of spheres in broth culture, a slow autolysis rate, and a low proportion of teichoic acid to peptidoglycan. Revertants of strain RUB1012 (RUB2032, RUB2012, and RUB2042) that could grow on tryptose blood agar base were isolated. Each revertant had a different proportion of teichoic acid to peptidoglycan. The nanomoles of phosphorus per milligram of cell wall at the nonpermissive temperature were 141, 160, 236, and 541 for strain RUB1012 and revertants RUB2032, 2012, and 2042, respectively, as compared with 1,100 for the parent strain. With most bacteriophage tested, plating efficiency was related to the amount of glucosylated teichoic acid. Scanning electron microscopy was used to study strain RUB2032 during a shift from growth at 30 degrees C to growth at 45 degrees C. The change from rod to sphere began with the thickening of the cylindrical portion of the cell. Caps of the cells appeared to be immune to the thickening process. During growth, the cells became progressively shorter and thicker, and cell separation was inhibited. When cells of strain RUB2032 were shifted from growth at 45 degrees C to growth at 30 degrees C, accumulation of an amorphous material on the outer surfaces of the cells preceded the change from sphere to rod morphology. Cells remained clumped, with rods appearing at the periphery of the clumps. Analysis by DNA-mediated transformation and PBS1-mediated transduction indicated that strains RUB1012 and RUB1013 have multiple mutations mapping in the same region as other cell wall mutations.     

Isolation and Purification of Drosophila Peripheral Neurons by Magnetic Bead Sorting

The Drosophila peripheral nervous system (PNS) is a powerful model for investigating the complex processes of neuronal development and dendrite morphogenesis at the functional and molecular levels. To aid in these analyses, we have developed a strategy for the isolation of a subclass of PNS neurons called dendritic arborization (da) neurons that have been widely used for studying dendrite morphogenesis^1,2. These neurons are very difficult to isolate as a pure population, due in part to their extremely low occurrence and their difficult-to-reach location below the tough chitinous larval cuticle. Our newly developed method overcomes these challenges, and is based on a fast and specific cell enrichment using antibody-coated magnetic beads. For our magnetic bead sorting studies, we have used age-matched third instar larvae expressing a mouse CD8 tagged GFP fusion protein (UAS-mCD8-GFP)³ under the control of either the class IV dendritic arborization (da) neuron-specific pickpocket (ppk)-GAL4 driver⁴ or the control of the pan-da neuron-specific GAL4^21-7 driver⁵. Although this protocol has been optimized for isolating PNS cells which are attached to the inner wall of the larval cuticle, by varying a few parameters, the same protocol could be used to isolate many different cell types attached to the cuticle at larval or pupal stages of development (e.g. epithelia, muscle, oenocytes etc.), or other cell types from larval organs depending upon the GAL4-specific driver expression pattern. The RNA isolated by this method is of high quality and can be readily used for downstream genomic analyses such as microarray gene expression profiling studies. This approach offers a powerful new tool to perform studies on isolated Drosophila dendritic arborization (da) neurons thereby providing novel insights into the molecular mechanisms underlying dendrite morphogenesis.Download video file.^{(149M, mp4)}     

Curling and Local Shape Changes of Red Blood Cell Membranes Driven by Cytoskeletal Reorganization

Human red blood cells (RBCs) lack the actin-myosin-microtubule cytoskeleton that is responsible for shape changes in other cells. Nevertheless, they can display highly dynamic local deformations in response to external perturbations, such as those that occur during the process of apical alignment preceding merozoite invasion in malaria. Moreover, after lysis in divalent cation-free media, the isolated membranes of ruptured ghosts show spontaneous inside-out curling motions at the free edges of the lytic hole, leading to inside-out vesiculation. The molecular mechanisms that drive these rapid shape changes are unknown. Here, we propose a molecular model in which the spectrin filaments of the RBC cortical cytoskeleton control the sign and dynamics of membrane curvature depending on whether the ends of the filaments are free or anchored to the bilayer. Computer simulations of the model reveal that curling, as experimentally observed, can be obtained either by an overall excess of weakly-bound filaments throughout the cell, or by the flux of such filaments toward the curling edges. Divalent cations have been shown to arrest the curling process, and Ca²⁺ ions have also been implicated in local membrane deformations during merozoite invasion. These effects can be replicated in our model by attributing the divalent cation effects to increased filament-membrane binding. This process converts the curl-inducing loose filaments into fully bound filaments that arrest curling. The same basic mechanism can be shown to account for Ca²⁺-induced local and dynamic membrane deformations in intact RBCs. The implications of these results in terms of RBC membrane dynamics under physiological, pathological, and experimental conditions is discussed.     

河南永城煤矿塌陷区水质对鲫鱼形态性状指标和脏器系数的影响

选择鲫鱼Carassius auratus为研究对象,以相对无煤矿污染的商丘市天沐湖为对照,以煤矿污染较严重的永城煤矿塌陷积水区为研究样地,主要研究了永城煤矿塌陷区水质对鲫鱼形态性状指标和脏器系数的影响.结果 表明,与对照天沐湖相比,永城煤矿塌陷区鲫鱼体重/全长显著减小(P＜0.05),但鲫鱼头长/全长、体长/全长、尾长/全长、体高/全长差异不显著(P＞0.05);脾脏系数显著减小(P＜0.01),头肾系数显著增大(P＜0.01),肝胰脏系数、肾脏系数、生殖腺系数差异不显著(P＞0.05).表明永城煤矿塌陷积水区长期低浓度煤矿污染对鲫鱼形态及其重要内脏器官可能造成了一定的影响.     

Morphological and Biochemical Changes During Programmed Cell Death of Rat Cerebellar Granule Cells

Cultured cerebellar granule cells deprived of depolarizing concentrations of KCl and serum die by programmed cell death. Recently, it was shown that serum removal by itself can lead to oxidative stress and DNA fragmentation in these cells. We have modified the protocol which initiates cell death in such a way that only the effect of KCl withdrawal-induced cell death was observed. We have performed a series of experiments to correlate the structural and biochemical changes in this process of cell death. Significant morphological alterations occur in cell bodies and neurites during a 48-hour period of KCl removal. Cell viability dropped to 53%, 34% or 10% of control levels, respectively, as a result of 1-, 2-, or 3-day KCl removal. A series of experiments was conducted to determine the change of total protein level, protein synthesis rate, RNA synthesis rate, and mitochondrial activity during the first 48 hours of KCl removal. These studies not only provide a picture correlating the morphological and biochemical changes in the process of programmed cell death, but also serve as a reference for future studies of this complex phenomenon.     

灰楸形态多样性分析及核心种质初步构建

根据对267个灰楸的15个相关性状的方差和主成分等统计分析结果,评价灰楸种质资源的形态多样性。并且将种质资源按地理流域进行分组,以欧氏距离结合离差平方和的方法进行系统聚类,以生产或育种过程中起过重要作用的品种为必选材料,初步构建了63份核心种质,占总种质的23.6%。63份核心种质和总种质遗传多样性t检验未达到显著水平,表明初步构建的灰楸核心种质能代表总体资源的遗传多样性。     

Magnetic Resonance Spectroscopy Studies on Changes in Cerebral Calcium and Zinc and the Energy State Caused by Excitotoxic Amino Acids

Under control conditions, superfused hippocampal slices exhibited a significantly higher phosphocreatine (PCr)/ATP ratio than cortical slices; the evidence suggests that this is due to lower concentrations of ATP, rather than higher concentrations of PCr. Glutamate caused relatively rapid decreases in PCr and ATP levels to approximately 45%, accompanied or immediately followed by an increased free intracellular calcium concentration ([Ca2+]i) and the release of Zn2+ in the cortex. In the hippocampus PCr and ATP decreased further to approximately 20% of control values, but the changes in [Ca2+]i and Zn2+ content were slower. This is in contrast to the effects of depolarisation, which produced the same rapid changes in the energy state and [Ca2+]i, with no detectable Zn2+, in both tissues. NMDA causes effects similar to those of glutamate in the cortex (decreases in the energy state, increased [Ca2+]i, and release of Zn2+). Pretreatment of the cortex for 1 h with the NMDA blocker MK-801 prevented all of the observed effects of NMDA. In contrast, pretreatment with MK-801 had no detectable effect on the increase in [Ca2+]i or the decreases in PCr and ATP caused by glutamate, although it prevented the release of zinc. The results are discussed in relation to the function of the NMDA subtype of glutamate receptor in excitotoxicity.     

Trapping, parasitism, and poisoning of nematodes by fungi

Naturally occurring toxins and nematode-destroying fungi are the two major factors controlling soil nematode populations. Nematode-destroying fungi fall into two groups - hyphal forms, producing traps which capture nematodes, and endoparasitic forms, both common in natural soils. Nematode-destroying fungi have been used in attempts to control levels of pathogenic nematodes in agricultural soils with limited success.     

Understanding Genetic Diversity and Population Structure of a Poa pratensis Worldwide Collection through Morphological,Nuclear and Chloroplast Diversity Analysis

Poa pratensis L. is a forage and turf grass species well adapted to a wide range of mesic to moist habitats. Due to its genome complexity little is known regarding evolution, genome composition and intraspecific phylogenetic relationships of this species. In the present study we investigated the morphological and genetic diversity of 33 P. pratensis accessions from 23 different countries using both nuclear and chloroplast molecular markers as well as flow cytometry of somatic tissues. This with the aim of shedding light on the genetic diversity and phylogenetic relationships of the collection that includes both cultivated and wild materials. Morphological characterization showed that the most relevant traits able to distinguish cultivated from wild forms were spring growth habit and leaf colour. The genome size analysis revealed high variability both within and between accessions in both wild and cultivated materials. The sequence analysis of the trnL-F chloroplast region revealed a low polymorphism level that could be the result of the complex mode of reproduction of this species. In addition, a strong reduction of chloroplast SSR variability was detected in cultivated materials, where only two alleles were conserved out of the four present in wild accessions. Contrarily, at nuclear level, high variability exist in the collection where the analysis of 11 SSR loci allowed the detection of a total of 91 different alleles. A Bayesian analysis performed on nuclear SSR data revealed that studied materials belong to two main clusters. While wild materials are equally represented in both clusters, the domesticated forms are mostly belonging to cluster P2 which is characterized by lower genetic diversity compared to the cluster P1. In the Neighbour Joining tree no clear distinction was found between accessions with the exception of those from China and Mongolia that were clearly separated from all the others.     

猫嗅球外丛层和僧帽细胞层年龄相关形态学变化

分别用Nissl法及免疫组织化学ABC法标记青、老年猫嗅球中嗅觉二级神经元和外丛层胶质细胞,显微镜下观察其分布并计数,对嗅觉二级神经元胞体直径和外丛层厚度进行测量,比较其年龄相关性变化,研究神经元与胶质细胞之间的关系,探讨老年性嗅觉功能衰退的相关神经机理。结果显示,老年猫嗅觉二级神经元胞体直径和分布密度均有不同程度的显著性下降(P<0.05);外丛层厚度变化不明显(P>0.05);外丛层胶质细胞特别是星形胶质细胞显著性增生(P<0.05)。表明在衰老过程中嗅觉二级神经元有丢失,并呈现功能下降,可能是老年性嗅觉功能衰退的原因之一。同时外丛层胶质细胞增生以进一步保护神经元,延缓其衰老。     

章古台固沙林引起下垫面热量平衡特征变化的分析

章古台位于辽宁省西北部彰武县境内,是科尔沁沙地的东南前哨。50年代初期,本区主要由流动沙丘、半流动沙丘和丘间低地组成,生态环境十分恶劣。为了治理风沙危害,改变生态环境,1952年在该地区进行大面积樟子松造林。现已有林地2150ha,成功地将光秃的沙丘改造成翠绿的森林环境。显然,下垫面的这种变化不仅会带来该地区生态环境的改变,也将引起局地小气候尤其是热量平衡特征相应的     

Morphological and Physiological Changes Induced by High Hydrostatic Pressure in Exponential- and Stationary-Phase Cells of Escherichia coli: Relationship with Cell Death

The relationship between a loss of viability and several morphological and physiological changes was examined with Escherichia coli strain J1 subjected to high-pressure treatment. The pressure resistance of stationary-phase cells was much higher than that of exponential-phase cells, but in both types of cell, aggregation of cytoplasmic proteins and condensation of the nucleoid occurred after treatment at 200 MPa for 8 min. Although gross changes were detected in these cellular structures, they were not related to cell death, at least for stationary-phase cells. In addition to these events, exponential-phase cells showed changes in their cell envelopes that were not seen for stationary-phase cells, namely physical perturbations of the cell envelope structure, a loss of osmotic responsiveness, and a loss of protein and RNA to the extracellular medium. Based on these observations, we propose that exponential-phase cells are inactivated under high pressure by irreversible damage to the cell membrane. In contrast, stationary-phase cells have a cytoplasmic membrane that is robust enough to withstand pressurization up to very intense treatments. The retention of an intact membrane appears to allow the stationary-phase cell to repair gross changes in other cellular structures and to remain viable at pressures that are lethal to exponential-phase cells.     

Morphological Comparison of Meloidogyne Female Head Structures,Perineal Patterns,and Stylets

The external morphology of female heads of three populations of each of two cytological races of Meloidogyne hapla (race A-meiotic, race B-mitotic) and single populations of M. arenaria, M. incognita, and M. javanica was compared by light (LM) and scanning electron microscopy (SEM). Perineal patterns of all nine populations were observed with a LM and then examined with a SEM. In addition, female stylets of each population were excised, viewed with a SEM, and compared with observations made with a LM. Head morphology of the females, including shape of medial and lateral lips, expression of sensilla, and head annulation, was distinct for each species, each race of M. hapla, and each population of M. hapla race A. The morphology of a given perineal pattern appeared similar with the SEM and the LM. The SEM emphasized surface details, whereas the LM revealed subcuticular structure as well. Stylet morphology was unique for each species but similar in all populations of M. hapla. There were differences between species in the shape of the cone, shaft, and knobs and in the distance of the dorsal esophageal gland orifice from the stylet knob base. Several of the morphological characters first detected in the SEM were seen subsequently with the LM and are helpful in species identification.     

Quantification of Dynamic Morphological Drug Responses in 3D Organotypic Cell Cultures by Automated Image Analysis

Glandular epithelial cells differentiate into complex multicellular or acinar structures, when embedded in three-dimensional (3D) extracellular matrix. The spectrum of different multicellular morphologies formed in 3D is a sensitive indicator for the differentiation potential of normal, non-transformed cells compared to different stages of malignant progression. In addition, single cells or cell aggregates may actively invade the matrix, utilizing epithelial, mesenchymal or mixed modes of motility. Dynamic phenotypic changes involved in 3D tumor cell invasion are sensitive to specific small-molecule inhibitors that target the actin cytoskeleton. We have used a panel of inhibitors to demonstrate the power of automated image analysis as a phenotypic or morphometric readout in cell-based assays. We introduce a streamlined stand-alone software solution that supports large-scale high-content screens, based on complex and organotypic cultures. AMIDA (Automated Morphometric Image Data Analysis) allows quantitative measurements of large numbers of images and structures, with a multitude of different spheroid shapes, sizes, and textures. AMIDA supports an automated workflow, and can be combined with quality control and statistical tools for data interpretation and visualization. We have used a representative panel of 12 prostate and breast cancer lines that display a broad spectrum of different spheroid morphologies and modes of invasion, challenged by a library of 19 direct or indirect modulators of the actin cytoskeleton which induce systematic changes in spheroid morphology and differentiation versus invasion. These results were independently validated by 2D proliferation, apoptosis and cell motility assays. We identified three drugs that primarily attenuated the invasion and formation of invasive processes in 3D, without affecting proliferation or apoptosis. Two of these compounds block Rac signalling, one affects cellular cAMP/cGMP accumulation. Our approach supports the growing needs for user-friendly, straightforward solutions that facilitate large-scale, cell-based 3D assays in basic research, drug discovery, and target validation.     

Morphological and Physiological Changes on Rhizopus stolonifer by Effect of Chitosan,Oligochitosan or Essential Oils

Effects of chitosan, oligochitosan and the essential oils of clove and cinnamon were evaluated on hyphal morphology, cell wall thickness, minimum medium pH changes and respiration of Rhizopus stolonifer. Changes in hyphal morphology were observed due to chitosan or oligochitosan treatment in this fungus. Mycelial branching, abnormal shapes and swelling were showed on hyphae of R. stolonifer treated with chitosan, whereas the development of hyphae was markedly inhibited by the effect of oligochitosan. Clove and cinnamon oils caused few morphological changes in the hyphae of R. stolonifer. Cell wall thickness was increased approximately 2‐ to 3‐fold by effect of chitosan, oligochitosan and the essential oil of clove. R. stolonifer grown in minimum medium generated a decrease in the medium's pH. However, the addition of chitosan or oligochitosan caused increases in pH of medium culture. The highest pH value (5.4) was observed in the presence of chitosan. The respiration of R. stolonifer was stimulated at low concentrations of chitosan, oligochitosan or essential oils. Significant changes in morphology and physiology of this fungus were demonstrated by the effect of all evaluated compounds. The most important changes were induced on cells of R. stolonifer treated with chitosan and oligochitosan.