Marqueur d’identification à micro-échelle de l’ivoire de mammouth dans les objets préhistoriques

This paper illustrates the importance of the material identification in order to be able to answer archaeological questions and describes the definition of new markers based on the chemical analysis and the study of the inner micro-morphology of the objects. The challenge for the identification of mammoth ivory is highlighted amongst prehistoric objects, which were heavily worked and used. The applied analytical approach is non-invasive to preserve the integrity of the rare and precious prehistoric objects. The objects are studied by means of Proton Induced X-ray emission (PIXE) and micro X-ray tomography (microCT). Examples of the study of objects dating back to the Upper Palaeolithic nicely illustrate the informative potential of this kind of investigations.     

Effect of molecular charge on choroid-plexus permeability: Tracer studies with cationized ferritins

Summary The permeability of the choroid plexus and renal glomerulus to intravenously injected native, anionic ferritin and various cationic ferritin derivatives was studied in normal rats by electron microscopy. In both structures, anionic, native ferritin was largely confined to the circulatory compartment while the cationic forms penetrated and accumulated within the filtration barriers. In the choroid plexus, cationic ferritin concentrated in relationship to the endothelial fenestrations and the subendothelial basal lamina region. In the glomerulus, there was also an inner concentration of cationic tracer and, in addition, an aggregation of tracer along the outer, subepithelial portion of the basal lamina. The results indicate that the localization of tracer within the filtration barrier of both the choroid plexus and renal glomerulus is directly related to the tracer's isoelectric point. The findings suggest that the choroid plexus, like the glomerulus, contains fixed anionic groups within the capillary wall which influence its permeability.     

Ultrastructural localization of glycogen in erythrocytes and developing erythrocytic cells in normal human bone marrow

Summary The periodic acid-thiosemicarbazide-silver proteinate (PA-TSC-SP) reaction was employed for the ultrastructural cytochemical localization of saliva-labile glycogen in the erythrocytic cells in normal human blood and bone marrow. Particulate glycogen was demonstrated in the cytoplasm of all developmental forms of erythrocytic cells from the proerythroblast through the reticulocyte; a few particles of glycogen also were present in mature erythrocytes even in the peripheral blood. Statistical evaluation of the number of glycogen particles in mid-plane cell sections at each morphological stage of development indicated a significant and stepwise decrease during cellular maturation. This change in glycogen content may reflect both cellular utilization and mitosis during the maturational sequence.Supported by Grant No. SR01AM 12084-15 from the National Institutes of Health, Bethesda, Maryland.Appreciation is expressed to Anita Topson, Barbara Speakmon and Marjorie Griffith for their technical assistance and to Dr. Gerald King for performing the bone marrow aspirations.     

Enhanced production of bioethanol and ultrastructural characteristics of reused Saccharomyces cerevisiae immobilized calcium alginate beads

Yeast immobilized on alginate beads produced a higher ethanol yield more rapidly than did free yeast cells under the same batch-fermentation conditions. The optimal fermentation conditions were 30 °C, pH 5.0, and 10% initial glucose concentration with 2% sodium alginate beads. The fermentation time using reused alginate beads was 10-14 h, whereas fresh beads took 24 h, and free cells took 36 h. All bead samples resulted in nearly a 100% ethanol yield, whereas the free cells resulted in an 88% yield. Transmission electron microscopy (TEM) showed that the shortened time and higher yield with the reused beads was due to a higher yeast population per bead as well as a higher porosity. The ultrastructure of calcium alginate beads and the alginate matrix structure known as the “egg-box” model were observed using TEM.     

Phytomonas serpens: cysteine peptidase inhibitors interfere with growth, ultrastructure and host adhesion

In this study, we report the ultrastructural and growth alterations caused by cysteine peptidase inhibitors on the plant trypanosomatid Phytomonas serpens. We showed that the cysteine peptidase inhibitors at 10 microM were able to arrest cellular growth as well as promote alterations in the cell morphology, including the parasites becoming short and round. Additionally, iodoacetamide induced ultrastructural alterations, such as disintegration of cytoplasmic organelles, swelling of the nucleus and kinetoplast-mitochondrion complex, which culminated in parasite death. Leupeptin and antipain induced the appearance of microvillar extensions and blebs on the cytoplasmic membrane, resembling a shedding process. A 40 kDa cysteine peptidase was detected in hydrophobic and hydrophilic phases of P. serpens cells after Triton X-114 extraction. Additionally, we have shown through immunoblotting that anti-cruzipain polyclonal antibodies recognised two major polypeptides in P. serpens, including a 40 kDa component. Flow cytometry analysis confirmed that this cruzipain-like protein has a location on the cell surface. Ultrastructural immunocytochemical analysis demonstrated the presence of the cruzipain-like protein on the surface and in small membrane fragments released from leupeptin-treated parasites. Furthermore, the involvement of cysteine peptidases of P. serpens in the interaction with explanted salivary glands of the phytophagous insect Oncopeltus fasciatus was also investigated. When P. serpens cells were pre-treated with either cysteine peptidase inhibitors or anti-cruzipain antibody, a significant reduction of the interaction process was observed. Collectively, these results suggest that cysteine peptidases participate in several biological processes in P. serpens including cell growth and interaction with the invertebrate vector.     

慈姑(Sagittaria sagittifolia L.)对环境镉胁迫因子的应答

主要研究了水环境中Cd²⁺污染对慈姑(Sagittaria sagittifolia L.)根的毒害影响。结果表明:在Cd²⁺胁迫下,慈姑根出现不同程度的褐变、发黑,生长受到限制;叶和根尖细胞超微结构受损,叶绿体膨大、类囊体排列紊乱、线粒体嵴减少、空泡化、染色质凝集等;根尖细胞在扫描电镜下呈细胞壁增厚、细胞形状扭曲和排列不规则现象。能谱分析结果表明随外界Cd²⁺浓度增大,单个慈姑根尖中的Cd²⁺含量升高,其他营养元素的吸收受到不同程度的影响。Cd²⁺对慈姑的毒害有明显的剂量效应和时间效应。     

Electrically induced gel-to-gel phase-transition in neurons

At the end of transcardial perfusions with ice-cold physiological saline for 30 min or with isoosmotic potassium chloride for 5 min, but immediately before perfusion fixation, condenser-discharge electric shocks were administered to rats through surface electrodes pressed onto the temporal muscles of the scalped skull. As a result, striking ultrastructural compaction came about in numerous neurons thinly scattered in certain brain areas. Its features displayed a high degree of similarity to those previously observed following the in vivo administration of the same kind of electric shocks. This surprising independence from the actual state of metabolism questions whether the ultrastructural compaction, induced either in vivo or post mortem, is the result of any cascade of enzyme-mediated processes. On the other hand, a physical mechanism, phase transition propagated by non-covalent free energy stored in a cytoplasmic gel structure, which was proposed recently to explain a mechanically induced similar ultrastructural compaction, appears to apply also to the present case.     

原发性纤毛运动障碍一例并文献复习

目的:报道1例原发性纤毛运动障碍(primary ciliary dyskinesia,PCD)患者的临床和病理资料,总结其临床特征和诊治要点。方法:对1例可疑原发性纤毛运动障碍患者进行病史采集、体格检查、胸部X线和CT、肺功能检查、支气管镜检查及支气管黏膜活检、电镜超微病理观察、染色体检查等相关检查,确诊为原发性纤毛运动障碍。结合该例患者诊治过程进行文献分析,明确原发性纤毛运动障碍的诊治要点及注意事项。结果:该例患者具有咳嗽、喘息等呼吸道症状,胸部X线及CT提示肺部感染及脏器全反位;肺功能提示基本正常且支气管激发试验为阴性;支气管镜检查示支气管反位及支气管炎症,取黏膜活检提示支气管黏膜慢性炎症改变;超微病理发现气道上皮细胞呈现形态扁平化、纤毛极性消失、细胞内纤毛,纤毛动力臂结构未见异常;染色体检查:46,XX,400-550条带阶段未见染色体异常;确诊为原发性纤毛运动障碍。结论:原发性纤毛运动障碍临床少见且复杂多样,容易漏诊和误诊。临床症状、胸部影像学、纤毛超微结构观察以及基因检测等相关检查联合应用有助于原发性纤毛运动障碍的临床诊断和治疗。对于呼吸道感染迁延不愈并发内脏反位者,无论有无鼻窦炎和支气管扩张,均应考虑原发性纤毛运动障碍存在可能,应当及时进行呼吸道黏膜超微病理学检查,以便尽早进行诊断和干预,减少和延缓并发症的发生。     

Ultrastructural distribution of poly (A)+ RNA during Trypanosoma cruzi-cardiomyocyte interaction in vitro: a quantitative analysis of the total mRNA content by in situ hybridization

Ultrastructural in situ hybridization was used to visualize the spatial distribution of poly (A)+ RNA and quantitate its relative amount within different cellular compartments of cardiomyocytes after T. cruzi infection. The amount of poly (A)+ RNA remained about the same up to 24 h post-infection. In contrast, its content was reduced 65% after 72 h of interaction, showing a marked decrease in the cell cytoplasm. This decline in poly (A)+ RNA level in host cell cytoplasm was concomitant with intracellular proliferation of T. cruzi amastigotes. Thus, T. cruzi may affect host cell cytoplasmic mRNA stability, associated with the parasite's intracellular multiplication.