bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scanning Electron Microscopic Study of the Eggs of the Warthog Louse (Haematopinus Phacochoeri)
Authors: Baker C , Green ED 
Published: July 2020

Abstract
The large eggs of Haematopinus phacochoeri are found attached to the long dorsal mane bristles of the diurnal warthog. The eggs are generally exposed to great environmental stresses such as excessive sunlight and temperature as well as the occasional plunge under water or mud during grooming. This investigation was therefore undertaken to determine how the eggs of H. phococoeri are adapted to tolerate the various environmental changes it is constantly exposed to. To our knowledge no other SEM study on the eggs of this species has been performed.
Specimens still attached to the bristles were fixed in 70% ethanol, dehydrated and ultrasonically cleaned. Some eggs were longitudinally sectioned with a razor blade to expose the chorionic layers. The eggs were critical point dried in liquid CO2, mounted and viewed by means of a Leica Stereoscan 420 scanning electron microscope.
The general structure of the shell consists of two layers of chorion, i.e. the endo-and exochorion. These two layers are attached at the pre-formed line of weakness at the operculum and again near the hydropyle. Elsewhere these two layers are completely separated by the respiratory layer.
A Transmission Electron Microscopy Study and Viability Evaluation of the Effect of 2450 MHz Microwaves on Candida albicans.
Authors: Melgoza C , Sepúlveda J , Moreno M , Rodríguez M A 
Published: July 2020

Abstract
Microwaves of 2450 MHz have been used as a heating procedure in food technology, tissue processing for histological studies (1), in medicine (2) and as a sterilization agent for medical devices (3). Experiments were carried out exposing yeast cells of Candida albicans suspended in growth media to different times of radiation at 750 watts in a commercial microwave oven. Batches of 5 tubes containing the cells suspension were radiated from 15 seconds to 3 minutes and colony counts were done after exposure. Viability ceased totally after one minute radiation. Samples were obtained from unexposed controls and tubes radiated for 15, 30, 45 and 60 seconds, centrifuged and the pellets fixed in 1.5% potasium permanganate. After embbeding in Epon, thin sections were obtained and stained with uranyl acetate. Micrographs were taken with a Zeiss EM-109 electron microscope. Cells showed alteration of internal membranes at early times, and later changes indicative of cytoplasmic coagulation and organelle disorganization were seen. At 15 seconds mitochondrial matrix showed alterations followed by damage of its membranes.
Characterization of Ustilago Hordei Fimbriae Using Scanning Transmission Electron Microscopy and Immunocytochemistry
Authors: Henry Caroll E , Salaam TL , Steward-Clark E , Craig Joyce , Reynolds Lennell 
Published: July 2020

Abstract
Sporidia of Ustilago hordei produce surface fimbriae which are important in conjugation and pathogenicity. This work focuses on fimbrial origin and production using transmission electron microscopy (TEM) and immunocytochemistry.
Wild type I4A sporidial cells cultured to log phase with rotary shaking in yeast extract glucose (YEG) growth for 48 h. at 21° C, were harvested by centrifugation at 8000 rpm, placed on formvar coated grids, negatively stained with 2% uranyl acetate and photographed in the JEOL 1200 STEM. Some cells were prepared for sectioning by fixation with gluteraldehyde and cacodylate buffer, post fixed in osmium tetroxide, dehydrated and embedded in epoxy and stained with uranyl acetate. The remainder of the cells were sheared in a blender to remove fimbriae. The defimbriated cells and 1 ml. of fimbrial suspension were presented to TEM. The rest of the fimbrial suspension was centrifuged at 30,000 rpm and he fimbrial pellet protein concentration was determined to be 1.345 nm. as assayed by UV adsorption.
Studies on the Dynamic Localization of GFP-Myosin During Cytokinesis in Live Cells
Authors: Sabry James , Moores Sheri , Ryan Shannon , Zang Ji-Hong , Spudich James A 
Published: July 2020

Abstract
Cell division is thought to be powered by the constriction of an actomyosin containing contractile ring found transiently in the cleavage furrow. Conventional myosin II plays a fundamental role in this process of cytokinesis where, in the form of a multimeric complex known as the bipolar thick filament, it is thought to be the molecular motor that generates the force necessary to cause ring constriction.
In order to study the dynamics of this protein in the dividing cell, we have made a fusion protein of the green fluorescent protein (GFP) and the amino terminus of the Dictyostelium myosin heavy chain (GFP-myosin), and imaged the location of this protein in dividing Dictyostelium cells were it is the only myosin II present in the cell. The addition of GFP does not compromise the functioning of the myosin motor as evidenced by the fact that purified GFP-myosin has solution ATPase and in vitro motility kinetics similar to that of non-labelled myosin. In addition, GFP-myosin fully complements the myosin null mutation for both development and cytokinesis in suspension suggesting that GFP-myosin acts as a regulated motor when expressed in cells.
Alterations in the Molecular Interaction of Bcl-2 and Bax During Apoptosis Assessed Using Fluroescence Resonance Energy Transfer (FRET) Microscopy and Green Fluorescent Protein (GFP)-Bax and Blue Fluorescent Protein (BFP)-Bcl-2 Expressing Proteins
Authors: Mahajan N , Herman B 
Published: July 2020

Abstract
Apoptosis or programmed cell death, is a mechanism of cellular demise which is believed to play a role in many physiological processes, and which when defective, can contribute to the pathogenesis of cancer. Apoptosis is stimulated in cells by the p53 tumor suppresser, Bax and El A proteins and inhibited by overexpression of Bcl-2 and adenovirus E1B 19 kDa oncoproteins. A role for altered apoptosis in cancer comes from recent reports which have documented that inactivation of p53 (which promotes apoptosis) and/or overexpression of bcl-2 (which inhibits apoptosis) occurs in numerous cancers. Recent work from our laboratory has shown that inactivation of p53 (either by physical complex formation between p53 and Human Papillomavirus (HPV) type 16- or 18- E6 protein or by mutation of p53), is associated with increased expression of bcl-2 in cervical carcinoma cells. The combination of inactive p53 and increased expression of bcl-2 may lead to inhibition of apoptosis and thereby contribute to the development or progression of cervical cancer.
Spectral Imaging of Chromogenic Dyes in Cytological Specimens
Authors: Macville Merryn , Speel Ernst-Jan , Soenksen Dirk , Hopman Ton , ThomasRied  
Published: July 2020

Abstract
Recently, spectral imaging has been successfully applied to 24-color fluorescence in situ hybridization (FISH), and it has evolved into a new powerful method for the analysis of structural and numerical chromosomal aberrations on metaphase spreads (spectral karyotyping) For cytological specimens it is often impossible to use fluorescence microscopy because of (fixation-induced) auto-fluorescence or prior cytological staining. Also, re-examination of archived fluorescent specimens is hampered by fading. However, the need for multi-parameter cytochemical analysis remains when rare or unique material is to be studied in research or clinical diagnosis. Multi-color bright-field microscopy using enzyme precipitates has become feasible for in situ hybridization as well as immunohistochemical detection. Conventional transmission microscopy optics have allowed up to three targets to be detected simultaneously. In parallel to 24-color FISH, we explored the potential of spectral imaging to increase the number of parameters to be analyzed in bright-field microscopy.
Measurement of the Dissociation Time Constant of Plasma Membrane Bound Protein Domains Using GFP Fusion Tags
Authors: Teruel Mary , Oancea Elena , Stauffer Thomas , Meyer Tobias 
Published: July 2020

Abstract
We have previously shown that the spatial dynamics of GFP-tagged proteins can be investigated by locally enhancing the fluorescence of GFP using a short UV-laser pulse. 1 We have since developed photobleaching and photoenhancement methods to study binding parameters of GFP-tagged protein domains in intact cells. Here we present an analysis procedure which uses either photobleaching or photoenhancement measurements to determine simultaneously (1) the lateral diffusion coefficient and (2) the dissociation time constant defined for a plasma membrane associated, GFP-tagged protein. The dissociation time constant is defined as the time required for the dissociation of 63% of bound protein and is a functionally relevant parameter related to the binding strength. High affinity interactions are associated with a slow dissociation time constant and low affinity interactions with a fast dissociation time constant. The dissociation time constant of a signaling protein also imposes a critical limit on the cellular response time for signal transduction.
Studies on the Green Fluorescence Protein Marked Autographa Californica Multiple Nucleopolyhedrovirus in Trichoplusia ni Larvae.
Authors: Brownwright AJ , Barrett JW , Palli SR 
Published: July 2020

Abstract
We have investigated the infection process of Green Fluorescence Protein marked Autographa Californica multiple nucleopolyhedrovirusCAcMNPV-GFP) under both light and electron microscopes. Enveloped virus particles were observed in the nucleus of columnar epithelial cells of the midgut 24 hours after feeding Trichoplusia ni larvae with AcMNPV-GFP infected freeze-dried larvae. by this time enveloped virus particles were also observed in the plasma membrane reticular system(PMRS) of midgut epithelial cells and nuclei of the tracheoblasts that are present in the connective tissue of the midgut. by 60 hours post feeding, tissues such as fat body and epidermis were showing enveloped virus particles in their nuclei while the the midgut epithelial cells were now largely devoid of virus.
Based on these results we propose that enveloped virions released from occlusion bodies in the lumen enter columnar epithelial cells and replicate in the nucleus. At the same time some of the virions enter the PMRS and get quick access to tracheoblasts present in the midgut connective tissue and thereafter to hemocytes present in the haemolymph.
Employment of a Bioreactor Vessel to Simulate Elements of Microgravity During Early Chick Heart Development
Authors: Norton WN , Wiens D 
Published: July 2020

Abstract
Formation of the chick heart is initiated when paired regions of the mesoderm migrate to a specific region in the primitive head. Certain cells eventually form a pair of endocardiac tubes that become the lining of the heart, while the remaining precardiac mesoderm ultimately differentiates into the myocardium. Fibronectin is suspected as a crucial component of the migratory process. Very few investigations have been conducted on the relationship between cell motility and microgravity.
The primary objectives of this investigation were to determine the effect of altered gravity on the production and distribution of fibronectin, an extracellular matrix glycoprotein, during embryonic development of the chick heart, and to ascertain the extent to which these alterations affect myogenesis or morphogenesis. A microgravity bioreactor vessel, originally designed by NASA as a low-shear culture system, was employed to culture the cellular expiants in a simulated microgravity environment. Fertile, White-Leghorn chicken eggs were incubated at 38°C for 32 hours in a humidified egg incubator.
The Effect of Tgfß-2 on Inner Ear Development: Light and Electron Microscopy Observations
Authors: Friedman R , Paradies N , Wert S , Doetschman T , Cardell EL 
Published: July 2020

Abstract
Transforming growth factor beta (TGFß) genes are linked to a variety of developmental processes and are the subject of in vivo and in vitro transgene research studies. We are evaluating TGFß-2 effects on mouse inner ear development, with emphasis on the cochlear duct (CD), by comparing plastic sections of intact inner ears from developmental day (D) 16.5,18.5 and 19.5 littermates with wildtype (+/+), heterozygous (+/−) and mutant (−/−) TGFß-2 genotypes as determined by polymerase chain reaction analysis of tail digests. Auditory and vestibular organs of all D16.5 mice appear similar: membranous labyrinth epithelium varies from simple cuboidal/low columnar to pseudostratified/stratified columnar. Surrounding mesenchyme varies in cell density regionally, the most cellular mesenchyme underlies areas of sensory epithelium. Sparse mesenchymal cell distribution in the vestibule and basal CD indicates sites of perilymph channel formation. The spiral and vestibular ganglia and their unmyelinated fibers are prominent. Otoconia and hair cells are present in the utricle (U) and saccule (S) maculae; hair cells are less easily identifiable in the CD.
An Electron Microscopic Study of Developing Synapses in Facial and Hypoglossal Motor Nuclei of the Brazilian Opossum.
Authors: Pepper TM , Swanson JJ , Kuehl-Kovarik MC , Jacobson CD 
Published: July 2020

Abstract
Previously, we have shown the apparent development of synapses utilizing immunohistochemistry (IHC) for synapse-associated proteins in the facial and hypoglossal motor nuclei of the Brazilian opossum. This study suggests that synaptogenesis is delayed in the facial motor nucleus (FMN) as compared to the hypoglossal motor nucleus (HMN). In the present study we plan to confirm and extend these findings at the electron microscopic (EM) level.
We have examined the ultrastructure of the developing FMN from animals 5 to 25 days of postnatal age (PN). The specific nuclei were identified using methylene blue stained 150 μm thick vibratome cut sections. The FMN and HMN were then dissected out for processing, guaranteeing that visualization at the EM level would be confined to areas specific to the nuclei of interest.
Initial analysis of the FMN indicates a marked increase of detectable synapses between 5 and 15PN.
Effects of Transforming Growth Factor-β1 on Decorin Expression by Undifferentiated Osteoblastic Cells
Authors: Bailey GW , Dimlich RVW , Alexander KB , McCarthy JJ , Pretlow TP , Yamada T , Kubushiro N , Shigemasa K , Ikeda T , Takagi M 
Published: July 2020

Abstract
Decorin is the predominant proteoglycan isolated from bone of several animal species. Bone matrix decorin appears to bind transforming growth factor β (TGF-β) and enhances its bioactivity. TGF-β is stored in bone matrix in abundant amounts and modulates the synthesis of bone matrix proteins by osteoblasts. Thus it appears to play a role in regulation of bone formation during the bone remodeling process. The effect of TGF-β on decorin expression in bone cells has been evaluated in murine osteoblastic cells, but the results are divergent depending on the experimental conditions and cell types used. The present study investigated the effect of TGF-βl on the expression of decorin mRNA in two clonal rat osteoblastic cell lines with different stages of differentiation, ROS-C26 (C26) and ROS-C20 (C20); C26 is a potential osteoblast precursor cell line that is also capable of differentiating into muscle cells and adipocytes; C20 is a more differentiated osteoblastic cell line.
Horse Radish Peroxidase Labelled Oligonucleotides and Tyramide Signal Amplification for Fluorescence in Situ Hybridization to Low Abundant Cytokine Mrnas
Authors: Corput Mariette van de , Gijlswijk Rob van , Bobrow Mark , Erickson Tom , Dirks Roel , Raap Ton 
Published: July 2020

Abstract
In recent years, Tyramide Signal Amplification (TSA) has gained acclaim as a very sensitive detection method for immunocytochemsitry and fluorescence in situ hybridization (FISH). To maximally exploit the great signal generation capacity of TSA in mRNA-FISH, minimizing signals emanating from non-specifically bound nucleic acid probe becomes of prime importance, because a specificity check of the signals observed in the cytoplasm is virtually impossible. We reasoned that utilization of synthetic oligonucleotides (ONTs) in stead of commonly used cDNAs or cRNAs would diminish non-specific probe binding and that direct Horse Radish Peroxidase (HRP) labelling of ONTs and TSA would enable their in situ detection.
This approach was first tested in metaphase DNA-FISH using chromosome-specific repeats as targets. Using bifunctional crosslinking chemistry and HPLC, 5’-hexylamino oligonucleotides for chromosome specific simple satellite and alphoid sequences were conjugated to HRP and purified. Following 15 - 20 min of situ hybridization of a single HRP-ONT probe to metaphase chromosomes and a direct flurochrome-tyramide detection step, such repeat targets could be visualized with high specificity and excellent signal-to noise ratio.
Comparative Genomic Hybridization to Dna Microarrays
Authors: Pinkel D , Segraves R , Sudar D , van Vliet L , Clark S , Chen C , Zhai Y , Gray JW , Albertson D G 
Published: July 2020

Abstract
Comparative genomic hybridization (CGH), which involves the simultaneous hybridization of differentially labeled total genomic DNA from test cells and reference normal cells to metaphase chromosomes, has been used extensively to screen tumor genomes for regions of DNA sequence copy number variation. Analysis of these hybridizations requires quantitative analysis of the ratio of intensities of the fluorescent hybridization signals as a function of position along the chromosomes, which basically serve as a convenient genetic map. The ratios need to be measured very accurately since changes of about ± 20% from the average for the genome indicate important genetic events. Widespread use of CGH over the past several years has identified numerous regions of the genome that may contain currently unknown cancer genes. For example, regions of increased copy number may indicate sites of oncogenes, while regions of copy number decrease relative to average for the genome may signify the presence of a tumor suppressor gene.
Molecular and Structural Studies on Dynein Associated Mutations in Chlamydomonas Flagella.
Authors: Porter ME , Myster S , Perrone C , O'Toole E 
Published: July 2020

Abstract
The dynein ATPases are a large family of motor enzymes that provide the driving force for flagellar motility and contribute to microtubule-based transport inside cells. The challenge for the field is to appreciate the functional significance of the multiple dynein motors, to determine how the cell assembles a motor complex and targets each motor to its appropriate location, and to understand how a cell regulates the activity of each motor to accomplish its specific task(s). In our laboratory, we have capitalized on the highly ordered structural organization of the flagellar axoneme and on the ease of genetic analysis in Chlamydomonas to ask how a single cell controls the assembly and activity of its multiple flagellar dyneins. In particular, we have focused our efforts on the inner dynein arms, which are both necessary and sufficient for normal flagellar motility. The significance of this work derives from the conservation of axoneme structure across species, as well as the numerous functional homologies between the flagellar and cytoplasmic dyneins.
Structure of Centrosomes and Chromosomes Through IVEM Tomography
Authors: Agard DA , Guenbaut Vincent , Moritz Michelle , Braunfeld MB , Zhang GuoFung , Sedat John W 
Published: July 2020

Abstract
Centrosome structure: The centrosome is the major microtubule-organizing center of animal cells - it initiates spindle formation at the onset of mitosis and plays an active role in chromosome segregation. At the most basic level, microtubule (MT) formation is regulated at least in part, through the functional availability of nucleation sites on the centrosome. Functional centrosomes can be isolated from Drosophila embryos. When visualized with IVEM Tomography (IVEM-T) ring complexes are visualized throughout the peri-centriolar material (PCM) (1). γ-tubulin has been implicated in MT nucleation. Through immuno-IVEM-T we have shown that the ring structures within the PCM, contain y-tubulin and further that the only place γ-tubulin is found is at the minus (nucleating) end of MTs (2). This strongly implicates these γ-tubulin containing ring structures in MT polymerization, until our studies there was no direct proof that γ-tubulin was located at the site of MT nucleation. Furthermore Zheng et al have been able to isolate similar ring structures that are soluble from both Xenopus and Drosophila embryos (3).
Automated Color Segmentation for Quantitative Microscopy
Authors: Gaddipati A , Vince DG , Cothren R M , Cornhill JF 
Published: July 2020

Abstract
Over the past decade, there has been increased interest in quantifying cell populations and morphological structures in tissue sections using image analysis systems. Automated analysis is now being used in limited pathological applications, such as PAP smear evaluation, with the dual aim of increasing the accuracy of diagnosis and reducing the review time. Applications such as these primarily use gray scale images and deal with cells that are well separated. Quantification of routinely stained tissue represents a more difficult problem in that objects can not be separated in gray scale and the images are more complex. Many of the existing semi-automated algorithms are specific to a particular application and are computationally expensive. Hence, we investigated general adaptive automated color segmentation approaches which alleviate these problems.
The first stage of this research concentrated on separating tissue color clusters in a color space histogram of the image.
Association of a Brush Border Myosin I-Like Protein with Vesicular Organelles of the Secretory Pathway in Chicken Enterocytes
Authors: Kömüves László G , Munson Scott , Bikle Daniel D 
Published: July 2020

Abstract
Brush border myosin I (BBMI) was first identified as a major constituent of the microvillus cytoskeleton, where it links the actin filaments of the microvillus core to the overlying plasma membrane. Recently, however, BBMI was also found on isolated Golgi membranes. This observation suggests that cytoplasmic BBMI might act as a molecular motor for apically targeted secretory vesicles.
In an earlier study from this laboratory a 105-110 kD protein was isolated from the chicken small intestine, which displayed several characteristics of the BBMI. Using an antibody against this BBMI- like protein (MLP), the protein was detected in the apical brush border of the enterocytes. The limited resolution of the light microscopic immunohistochemical techniques used in that investigation, however, did not provide information about the intracellular distribution of MLP in the enterocytes.
In this study the intracellular localization of MLP was characterized using post-embedding colloidal gold immunocytochemistry. Pieces of the jejunum from 6-week-old male White Leghorn chickens were fixed and embedded in LR Gold resin.