bluuebunny/crossref_metadata_2025_split huggingface dataset:
Al localization in plant roots using EDXA and EELS techniques
Authors: Marienfeld Stephan F.-W. , Stelzer Ralf , Lehmann Heiner 
Published: June 2020

Aluminum, which is soluble at pH 5.0 is toxic to plants and frequently the most important yield limiting factor of crop production, on acid soils. Moreover, Al has been associated with human mental diseases (e.G. Alzheimer).Phytotoxicity of Al primarily results in adecline of mitotic activity of the root meristem, an evident reduction of root growth and subsequently affects mineral nutrition and water supply. Several authors assume a shifting of Alin to the nucleus and a direct influence on DNA-synthesis to be the reason for this growth reduction. However, Al in nucleus has only been demonstrated after preparations allowing Al to shift during this preparation. Using SEM and microprobe-analysis, it was only possible to demonstrate Al in roots mainly to be absorbed (as Al-phosphate) in cell walls. A quantification in cytoplasma or even a localisation in distinct organelles (e.g. the nucleus) fails due to the low tracability and the in sufficient resolution.Therefore, in addition to EDX-analysis we try to localize Al by using electron spectroscopic imaging (ESI) and electron energy loss spectroscopy (EELS) techniques, which are distinguished by an excellent spatial resolution and a high sensitivity. So element scan be analyzed and localized in small cell compartments. For those observations the plant material has to be fixed, embedded and cutin ultrathin sections. During chemical fixation procedure, however, the membranes lose their semipermeability and substances may be extracted or shifted inside the tissue or the cells. There fore elemental analysis must be done only under special conditions.
Application of video EM and image processing for evaluation of barrier tissues endocrine activity after environmental chemical exposure
Authors: Ptashekas J. 
Published: June 2020

Biotesting procedure of new environmental chemicals is unavoidable within framework of environmental medicine and public health. Micrographs in transmission electron microscopy are indispensable for evaluation of fine details of ultrastructure of diffuse endocrine system cells located in barrier epithelial tissues of gastrointestinal tract. At the same time it is insufficient to obtain integrated image and tissue functional activity analysis. Videoprocessed electron microscopy provides for full section (s) visual information and is applicable in environmental medicine.Wistar rats 250-280 gr b.w. had been once tube fed with 0.1 DL50 solution of piperasin derivative herbicide saprol (Celamerck, FRG) and investigated 15 min., 4 h and 24 h after treatment. Vertical samples of pyloric mucosa were prepared for transmission electron microscopy (TEM). Separate types of gastric endocrine cells had been verified ultrastructurally from micrographs according to lausanne (1981) Enteroendocrine Cells Classification. TEM image had been videoprojected to the monitor and computer processed to obtain distinct electron optical density, maturity level and number of secretory granules within 1 sq mkm of endocrine cell cytoplasma. Granules size (nm) frequency distribution histograms provided as well.
Radioactive and Non-Radioactive In Situ Hybridization Techniques
Authors: Durrant I. 
Published: June 2020

In situ hybridization is a powerful technique that has found multiple applications in the biological sciences. The most widely used technique is in the analysis of mRNA species in cell populations. This is particularly useful for the analysis of relative amounts, site of transcription, timing and induction of transcription. Recent advances have lead the technique into the areas of relative quantification, dual signal detection and disease diagnosis. DNA targets can also be visualised by in situ hybridization both in cells and tissues and on isolated chromosomes and nuclei. There are a variety of systems that can be used to detect hybridization signals in situ. These choices are based in two areas, probe type and label type and this selection process holds true for both radioactive and non-radioactive systems.Probe selection is important and plays a part in the overall success of the application (see Table
1). RNA probes and oligonucleotide probes are the most widely used in cells and tissues whereas
DNA probes are routinely used for chromosome and nuclei targets. RNA probes are used due to
the higher sensitivity obtained but oligonucleotide probes are gaining in popularity due to ease
of use. The lower sensitivity seen with these probes, due to lower labelling capacity, can be
overcome by use of probe cocktails.
Magnetic Resonance Analysis of Mouse Embryos with Altered Gene Expression
Authors: Smith B. R. 
Published: June 2020

Techniques to assess and analyze phenotypes of experimentally altered animals have not kept pace with our ability to manipulate the genome. Assessment of the shape, position, and timing of the appearance of anatomical structures is indispensable to identifying and understanding the mechanisms of normal and abnormal morphogenesis. Tools are needed to effectively diagnose the condition of the hundreds of experimentally altered animals being produced.Magnetic resonance (MR) microscopy is a non-destructive technique capable of generating three-dimensional images of developing structures from whole embryos. It facilitates the evaluation of complex anatomical structures by allowing them to be studied in any plane of sectioning for cut-away views and from any angle for surface views.MR microscopy has been used to assess the following mutant mouse embryos and mouse embryos with altered gene expression: Splotch, Curly-tail, Loop-tail, TS 16, HOX 2.2 transgenic, MARKS knockout, LH-2 knockout, and Dlx-2 knockout. Imaging was performed on a modified 9.4 Tesla GE NMR Instruments Omega system with echo times of 6 ms and repetition times of 200 ms.
MH27 Binds to Several Types of Epithelial Junctions by Em-Immuncytochemistry in the Nematode C. Elegans
Authors: Hall David H. 
Published: June 2020

The monoclonal antibody MH27 was used to test a post-embedding method for EM immunocytochemistry in the nematode C. elegans. Primary antibody localization was performed on LR Gold thin sections of lightly fixed him-5 adult animals, followed by a gold-linked anti-mouse IgG secondary antibody (AuroProbe, Amersham Life Science) and viewed on a Philips CM 10 electron microscope. Methods for fixation, embedding, sectioning and antibody procedures followed those of Selkirk et al. (1990) and Hall (1995). Relatively few examples of immunolabelling have been previously demonstrated in C. elegans at the EM level. We have previously found that LR White embedment was unsuitable, as it causes severe shrinkage in nematode tissues. Selkirk and coworkers showed that LR Gold was preferable for EM-immunocytochemistry, and used it to localize several surface antigens. Okamoto and Thomson (1985) previously demonstrated successful results with post-embedding labeling of Epon embedded material, but we anticipate that many antigens will not be well exposed in an Epon thin section.MH27 was generated during a search for specific antibodies to muscle proteins (Francis and Waterston, 1985). The antibody is now widely used for immunofluorescence studies to demarcate the boundaries of the hypodennal cells, and has proven useful to follow cellular development during embryogenesis and larval stages in C. elegans and other nematode species (Fitch and Emmons, 1995). We were interested to learn the ultrastructural localization of the MH27 antibody, as well as to further develop this technique for C. elegans tissues. We used the him-5 strain so that both male and hermaphrodite animals could be sampled.
An Ultrastructural Comparison of Hepatocytes from ADH+ and ADH−Peromyscus Maniculatus
Authors: Ellzey J. T. , Borunda D. , Stewart B. P. 
Published: June 2020

Genetically alcohol deficient deer mice (ADHN/ADHN) (obtained from the Peromyscus Genetic Stock Center, Univ. of South Carolina) lack hepatic cytosolic alcohol dehydrogenase. In order to determine if these deer mice would provide a model system for an ultrastructural study of the effects of ethanol on hepatocyte organelles, 75 micrographs of ADH+ adult male deer mice (n=5) were compared with 75 micrographs of ADH− adult male deer mice (n=5). A morphometric analysis of mitochondrial and peroxisomal parameters was undertaken.The livers were perfused with 0.1M HEPES buffer followed by 0.25% glutaraldehyde and 2% sucrose in 0.1M HEPES buffer (4C), removed, weighed and fixed by immersion in 2.5% glutaraldehyde in 0.1M HEPES buffer, pH 7.4, followed by a 3,3’ diaminobenzidine (DAB) incubation, postfixation with 2% OsO4, en bloc staining with 1% uranyl acetate in 0.025M maleate-NaOH buffer, dehydrated, embedded in Poly/Bed 812-BDMA epon resin, sectioned and poststained with uranyl acetate and lead citrate. Photographs were taken on a Zeiss EM-10 transmission electron microscope, scanned with a Howtek personal color scanner, analyzed with OPTIMAS 4.02 software on a Gateway2000 4DX2-66V personal computer and stored in Excel 4.0.
An Early Developmental Marker for Radial Glia in Rat Spinal Cord
Authors: Kriho V. , Yang H.-Y. , Lue C.-M. , Lieska N. , Pappas G. D. 
Published: June 2020

Radial glia have been classically defined as those early glial cells that radially span their thin processes from the ventricular to the pial surfaces in the developing central nervous system. These radial glia constitute a transient cell population, disappearing, for the most part, by the end of the period of neuronal migration. Traditionally, it has been difficult to definitively identify these cells because the principal criteria available were morphologic only.Using immunofluorescence microscopy, we have previously defined a phenotype for radial glia in rat spinal cord based upon the sequential expression of vimentin, glial fibrillary acidic protein and an intermediate filament-associated protein, IFAP-70/280kD. We report here the application of another intermediate filament-associated protein, IFAP-300kD, originally identified in BHK-21 cells, to the immunofluorescence study of radial glia in the developing rat spinal cord.Results showed that IFAP-300kD appeared very early in rat spinal cord development. In fact by embryonic day 13, IFAP-300kD immunoreactivity was already at its peak and was observed in most of the radial glia which span the spinal cord from the ventricular to the subpial surfaces (Fig. 1). Interestingly, from this time, IFAP-300kD immunoreactivity diminished rapidly in a dorsal to ventral manner, so that by embryonic day 16 it was detectable only in the maturing macroglial cells in the marginal zone of the spinal cord and the dorsal median septum (Fig. 2). By birth, the spinal cord was essentially immuno-negative for this IFAP. Thus, IFAP-300kD appears to be another differentiation marker available for future studies of gliogenesis, especially for the early stages of radial glia differentiation.
Ultrastructural Localization of Antigens by Capillary Action Immunocytochemistry
Authors: Kömüves László G. 
Published: June 2020

Light microscopic immunohistochemistry based on the principle of capillary action staining is a widely used method to localize antigens. Capillary action immunostaining, however, has not been tested or applied to detect antigens at the ultrastructural level. The aim of this work was to establish a capillary action staining method for localization of intracellular antigens, using colloidal gold probes.Post-embedding capillary action immunocytochemistry was used to detect maternal IgG in the small intestine of newborn suckling piglets. Pieces of the jejunum of newborn piglets suckled for 12 h were fixed and embedded into LR White resin. Sections on nickel grids were secured on a capillary action glass slide (100 μm wide capillary gap, Bio-Tek Solutions, Santa Barbara CA, distributed by CMS, Houston, TX) by double sided adhesive tape. Immunolabeling was performed by applying reagents over the grids using capillary action and removing reagents by blotting on filter paper. Reagents for capillary action staining were from Biomeda (Foster City, CA). The following steps were performed: 1) wet the surface of the sections with automation buffer twice, 5 min each; 2) block non-specific binding sites with tissue conditioner, 10 min; 3) apply first antibody (affinity-purified rabbit anti-porcine IgG, Sigma Chem. Co., St. Louis, MO), diluted in probe diluent, 1 hour; 4) wash with automation buffer three times, 5 min each; 5) apply gold probe (goat anti-rabbit IgG conjugated to 10 nm colloidal gold, Zymed Laboratories, South San Francisco, CA) diluted in probe diluent, 30 min; 6) wash with automation buffer three times, 5 min each; 7) post-fix with 5% glutaraldehyde in PBS for 10 min; 8) wash with PBS twice, 5 min each; 9) contrast with 1% OSO4 in PBS for 15 min; 10) wash with PBS followed by distilled water for5 min each; 11) stain with 2% uranyl acetate for 10 min; 12) stain with lead citrate for 2 min; 13) wash with distilled water three times, 1 min each. The glass slides were separated, and the grids were air-dried, then removed from the adhesive tape. The following controls were used to ensure the specificity of labeling: i) omission of the first antibody; ii) normal rabbit IgG in lieu of first antibody; iii) rabbit anti-porcine IgG absorbed with porcine IgG.
NMR, crystallography, and electron microscopy of nucleoprotein complexes
Authors: Ottensmeyer F. P. 
Published: June 2020

The forte of electron microscopy in biology is its unique ability to elucidate the very diverse structures of biological specimens at a range of sizes, with relationships within tissue sections, between and within cells, subcellular organelles, and macromolecules, for the latter with increasingly finer detail. It is the relationship between molecules that is the essence of biology, and it is here that a major emphasis in effort has been placed in recent years in terms of structure determination, not only in electron microscopy, but also in fields with complementary structural approaches, such as the classical x-ray crystallography and the much more recent NMR spectroscopy. The spatial relationship between nucleic acids and proteins is only one facet of this effort, albeit a most important one.Conventionally electron microscopy has a spatial resolution of about 20 Å in stained biological specimens, but has succeeded with near-atomic resolutions in several cases. NMR spectroscopy per force has to start at atomic dimensions, since its inter-nuclear signals are only available at short range. It builds outward mathematically to molecular dimensions. In the process the technique has permitted the elucidation of detailed interactions, not only between atoms on the same molecule, but in a number of instances between atoms of interacting macromolecules.
The use of an internal standard in the application of quantitative image-EELS in biology
Authors: Abolhassani-Dadras S. , Vázquez-Nin G.H. , Echeverría O.M. , Fakan S. 
Published: June 2020

The energy filtering transmission electron microscope (EFTEM) is employed to examine the possibility of using ribosomes as internal standard for a quantitative in-situ study of phosphorus content of nuclear constituents in a biological section. The problems that can arise from different steps of such an experimental approach are discussed.Salivary gland cells from fourth instar larvae of Chironomus thummi are selected as test specimens because of their appropriate structure. The nucleus of these cells contains two types of granules, one of which (known as Balbiani ring granule, Brg) has an RNA size known from radioactive phosphorus labelling and subsequent isolation, allowing one to estimate its phosphorus content. The other type of granule (known as small RNP granule) has been recently discovered and its phosphorus content is not known. The EFTEM method is used to verify the phosphorus content of these two nuclear constituents.
Biological crystals formation studied by HTREM and image analysis
Authors: Houlle P. , Cuisinier F.J.G. , Voegel J.C. , Schutz P. 
Published: June 2020

High resolution electron microscopy (HREM) allows the determination of the molecular crystal structure by comparing HREM images with simulated images. Direct comparison was not possible for small crystalline areas such as nanometer-sized particles or for thin crystals with weak image contrast. To overcome these problems, we used numerical image analysis to gain access to the structure informations within these minute crystals. We used this approach for the characterization of the initial mineralization steps during human amelogenesis, chicken bone and human dentine crystals growth.Our method consists in HREM associated with both numerical image analysis and image simulation techniques (EMS) Image analysis was performed using the IMAGIC statistical. Nanoparticle subimages, 128 × 128 pixels in size, were extracted from the original micrographs by interactive selection. A circular mask with a radius of 50 pixels was applied. The mean intensity of each subimage was set to zero and its internal variance was normalized to 10. Double direct alignment procedures were used to align the images in rotation and translation against an alignment reference extracted from the data set. An average image was finally calculated to improve the signal to noise ratio.
Scanning electron microscopy of early infection of dyers woad, Isatis tinctoria by germlings of Puccinia thlaspeos
Authors: Binns M. T. , Hooper G. R. , Kropp B. R. , Hansen D. R. , Thomson S. V. 
Published: June 2020

Dyers Woad (Isatis tinctoria) is an introduced noxious weed of crop and rangeland in northern Utah. A native rust fungus (tentatively identified as Puccinia thlaspeos) is being investigated as a possible biological control agent of the weed. In order to effectively use the rust in a bio-control program, it is necessary to understand its epidemiology and characteristics.Weeds were inoculated by suspending previously infected weed leaf fragments over test plants. Teliospores on these fragments produced basidiospores which dropped onto the weed seedling leaf surfaces. Inoculated leaves were prepared for SEM by fixation in 2% cacodylate buffered glutaraldehyde, post fixed in 2% buffered osmium tetroxide and dehydrated through ethyl alcohol and critical point dried. Mounted specimens were sputter-coated with gold. Some tissues were freeze fractured in 100% alcohol and fragments were critical point dried, coated and mounted for SEM.
SEM study of phytoliths produced by grasses indigenous to the desert experimental range in southwestern utah
Authors: Carver Melanie R. , Ball Terry , Gardner John S. , Erickson Kali M. 
Published: June 2020

The USDA Desert Experimental Range Station located in southwestern Utah has been conducting an ongoing investigation into the effects of grazing on the ecology of the region, The study reported herein is a preliminary effort to determine if phytolith analysis can be used to gain insight into the ecology of the region prior to the 60 year period over which records have been kept.Phytoliths are solid deposits of silicon dioxide that form at specific intracellular and extracellular locations in many plant taxa. Grasses produce phytoliths with morphological characteristics diagnostic of their taxa. When a plant dies, its phytoliths resist decomposition thereby becoming micro-fossils of the plant that produced them. Micro-fossil phytoliths provide archaeobotanical and ecological information because they remain in the same soil horizon at which decay occured. In this study phytoliths produced by four grasses indigenous to the Experimental Range were analyzed. Phytoliths extracted from soil samples of different grazing treatments at the Range were then analyzed to determine if any similar to those produced by the four grasses could be identified in the soil. If so, then phytolith analysis could prove to be a viable research tool for those studying the paleoecology of the Range.
Cytochemical localization of chloride in the leaves of Ruppia maritima L
Authors: Barnabas A. D. 
Published: June 2020

Ruppia maritima L. is a submerged halophyte which occurs frequently in estuaries where sodium chloride is the dominant salt. Unlike terrestrial halophytes, R. maritima does not possess any specialized salt-secreting structures such as salt glands. Knowledge of salt tolerance mechanisms in this plant is important to our understanding of its biology. In the present study, the subcellular distribution of chloride ions in leaf blade epidermal cells of R. maritima was determined.Chloride ions in the cells were localized by precipitation with silver, resulting in the formation of silver chloride (AgCl2) deposits. Leaf samples were fixed in a mixture of osmium and silver acetate under red safe light conditions to prevent reduction of silver by light. The material was dehydrated and embedded in a chloride-free resin. Leaf samples fixed only in osmium were used as controls. Transmission electron microscopy (TEM) and energy dispersive X-ray (EDX) microanalysis using a Joel 6100 SEM with a Noran Voyager 2100 EDX microanalyser, were used to study AgCl2 distribution. Ultrathin sections for TEM were examined unstained. EDX microanalysis was performed on thick sections of resinembedded material mounted on glass slides.
The study of multiphase polymer-blend morphologies by HVEM
Authors: Cavanaugh T.J. , Buttle K. , Turner J.N. , Nauman E.B. 
Published: June 2020

Multiphase polymer blends are important in the polymer industry. Most commercial blends consist of two main polymers combined with a third, compatibilizing polymer, typically a graft or block copolymer. The most common examples are those involving the impact modification of a brittle thermoplastic by the microdispersion of a rubber into the matrix. Recently, a model of ternary polymer blends has provided a wealth of morphologies for examination. Even though this model can give an excellent basis for the design of a polymer blend, experimental verification is necessary. A correlation of blend properties such as impact strength with blend morphology must also be made. The focus is to confirm the predicted morphologies in binary and ternary blends using HVEM.The polymer blends were produced by compositional quenching. In this process, the polymers were dissolved in a solvent. The solution was pumped through a heat exchanger and then flashed across a needle valve to remove the solvent.
Length-Scale-Dependent surface roughness measurements of bioactive polymer thin films using scanning probe microscopy
Authors: Buchko Christopher J. , Kozloff Kenneth M. , Martin David C. 
Published: June 2020

The development of implantable biomedical devices requires active biological interfaces that minimize the body’s immune response. We have identified candidate protein polymer coatings for biomedical applications and methods of processing these coatings that promote a favorable in vitro biological performance. However, the chronic implantation of biomedical devices, specifically the neural prosthetic devices developed at the University of Michigan, places additional requirements on the polymer coatings. Among these constraints are the efficient transport of neuronal signals from tissue to the device and the prevention of physical displacement of the device through tissue. To meet these potentially conflicting goals, we are developing discontinuous, porous polymer coatings that are rough at biologically-relevant length scales.In order to quantify the surface morphology of these thin polymer films, which are typically 0.02 μm to 5.0 μm thick, we employ a number of complementary techniques, including scanning probe microscopy (SPM), scanning electron microscopy (SEM), light optical microscopy (LOM), and transmission electron microscopy (TEM).