Double-layered Cell Research Articles

Use of PCR-restriction fragment length polymorphism for the identification of zoonotic mycobacteriosis in zebrafish caused by Mycobacterium abscessus and Mycobacterium chelonae

Skin ulcers, scoliosis, and dropsy-like scale edema were observed in laboratory-maintained zebrafish. Affected fish had multifocal granulomas not only in internal organs such as the liver, intestine, genital organs, kidney, muscle, and spleen but also in the fin, epithelium, gills, and sclera of the eyes. Large numbers of acid-fast-rod-shaped bacteria were observed within the necrotic centers of well-demarcated, multifocal granulomas with Gram's stain and Ziehl–Neelson's stain. The size of the Mycobacterium spp. was 1–2 μm × 2–3 μm with a double-layered cell wall, based upon electron-microscopical features. Definitive diagnosis of these outbreaks was obtained by culture on selective media followed by PCR-restriction fragment length polymorphism analysis (PRA) of the rpoB gene for species identification. The amplified 360-bp products of the rpoB gene of mycobacteria isolated from zebrafish were digested with MspI restriction enzyme, which revealed unique band patterns matching those of Mycobacterium abscessus and Mycobacterium chelonae which are responsible for skin and soft tissue infection caused by rapidly growing mycobacteria in humans. This is the first documentation of the precise identification of zoonotic non-tuberculous mycobacteria isolated from laboratory-maintained zebrafish by the PRA of the rpoB gene; this study thus provides a great deal of useful epidemiological information and reduces the likelihood that epizootics will occur.

Effects of media composition on submerged culture spores of the entomopathogenic fungus, Metarhizium anisopliae var. acridum, Part 1: Comparison of cell wall characteristics and drying stability among three spore types

Metarhizium anisopliae var. acridum (IMI 330189) can produce at least three spore types in vitro; blastospores, submerged conidia, and aerial conidia, as defined by culturing conditions, sporogenesis, and spore morphology. This study compares morphological characteristics (dimensions and cell wall structure), chemical properties of cell wall surfaces (charge, hydrophobicity, and lectin binding), and performance (germination rate and drying stability) among these three spore types. Submerged conidia and aerial conidia both possessed thick, double-layered cell walls, with hydrophobic regions on their surfaces. However, in contrast to aerial conidia, submerged conidia have: (1) a greater affinity for the lectin concanavalin-A; (2) more anionic net surface charge; and (3) a less distinct outer rodlet layer. Blastospores were longer and more variable in length than both submerged conidia and aerial conidia, and had thinner single-layered cell walls that lacked an outer rodlet layer. Also, blastospores had a greater affinity than either conidia type for the lectin, wheat germ agglutinin. Blastaspores lacked hydrophobic regions on their surface, and had a lower anionic net surface charge than submerged conidia. In culture, blastospores germinated the fastest followed by submerged conidia, and then aerial conidia. Survival of submerged conidia and aerial conidia were similar after drying on silica gel, and was greater than that for blastospores. We provide corroborating information for differentiating spore types previously based on method of production, sporogenesis, and appearance of spores. These physical characteristics may have practical application for predicting spore-performance characteristics relevant to production and efficacy of mycoinsecticides.

Single- and double-layered mesoporous TiO2/P25 TiO2 electrode for dye-sensitized solar cell

Abstract Nanocrystalline mesoporous titania (MP-TiO 2 ) was synthesized by surfactant-assisted templating method using tetraisopropyl orthotitanate modified with acetylacetone and laurylamine hydrochloride as template. The short-circuit photocurrent density ( J sc ) of the cell made from MP-TiO 2 was much higher than that of the cell made from commercial P25 titania. The incident photon to current conversion efficiency (IPCE) spectra of thin MP-TiO 2 cell were higher than that of thick P25 cell in the region between 400 and 475 nm but lower than that of thick P25 cell in the red region, because the thickness of thin transparent MP-TiO 2 film was not enough to scatter the light leading to low absorbed spectra in red region. IPCE spectra of MP-TiO 2 can be improved by using the cell made from blended MP-TiO 2 with P25. The cell performance was improved with increasing sintering temperature. Double-layered titania cells were also fabricated to further improve the cell performance by increasing light scattering and amount of adsorbed dye. The solar energy conversion efficiency ( η ) up to 8.1% was obtained by using the double-layered titania cell sintered at 450 °C for 2 h.

Imaging Properties of Double-Layered Liquid Crystal Microlens

A liquid crystal (LC) microlens for obtaining an erect image is designed using LC director orientation simulation and ray tracing, where relationships between LC material and structural parameters of the double-layered LC microlens cell and its optical properties are calculated. Then, the double-layered LC microlens is fabricated based on the simulation results. The dependence of the working distance on the magnification of the image is discussed experimentally and theoretically. An erect image of unit magnification with a designed working distance is obtained by the double-layered structure. Lens properties such as magnification are continuously controlled and image direction can be switched by changing the voltage applied to the LC microlens cell.

Interfacial Characteristics of Organic Electroluminescent Devices (OELDs) Using Impedance Technique

We studied the effect of bias voltage on the impedance spectra of a double-layered cell. When bias-voltage was applied, bulk resistance was reduced due to the increased number of carriers but total capacitances increased very much due to more polarization at interfaces. When compared with single-layered cell, double-layered cell resulted in the lower turn-on voltage, which may be related to the increased interfacial impedance.

Vapor-deposited poly(N-vinylcarbazole) films for hole transport layer in organic electroluminescent devices

Vapor-deposited films of poly(N-vinylcarbazole) (PVCz) were used as hole transport layers in organic electroluminescent devices. Hole transporting ability of the vapor-deposited PVCz films in the double-layered cell remarkably depended on their film morphology. Light emission was obtained only when a thin, homogeneous PVCz film (10–15 nm in thickness) was deposited on an anode substrate which was kept at 100°C during deposition. When the PVCz film was overcoated on a low molecular hole transporting layer, the EL performance of the mutilayered device was retained for a longer time as compared with that without the PVCz deposition. This improved durability was ascribed to the PVCz layer which prevents the low molecular layer from being degraded by aggregation.

Asexual Sporulation inCoprinus cinereus:Structure and Development of Oidiophores and Oidia in anAmut BmutHomokaryon

Polak, E., Hermann, R., Kües, U., and Aebi, M. 1997. Asexual sporulation inCoprinus cinereus:Structure and development of oidiophores and oidia in anAmut Bmuthomokaryon.22,112–126.Coprinus cinereusstrain AmutBmut is a homokaryon with mutations in both mating type loci. It produces asexual spores (oidia) in sticky liquid droplets on specialized aerial structures (oidiophores). These oidiophores have uninucleate cells and are organized as those of the monokaryon 5026 from which the strain derived. However, unlike in the monokaryon, oidiophores in strain AmutBmut are induced by light. Young oidiophores are easily detected upon light induction and the process of oidiophore development is readily followed in this strain. Fully grown oidiophores consecutively give rise to short branches (oidial hyphae) that break up into two or occasionally three uninucleate oidia (arthroconidia) until up to 200 oidia are collected at the tip of the oidiophore. Mature spores are enclosed by a mucilage and a double-layered primary cell wall with hair-like structures except for the sides of former cell attachments. In a summary of our microscopic observations on developing oidiophores and nuclear stainings we present a model showing the successive steps of oidiophore and spore development.

An electronmicroscope study of glycopeptide antibiotic-resistant strains of Staphylococcus epidermidis.

Ultra-thin section transmission electronmicroscopy revealed that two of three glycopeptide-resistant strains of Staphylococcus epidermidis had abnormally thick cell walls, a finding consistent with the view that the reduction in susceptibility may result from the overproduction of glycopeptide binding sites within the cell-wall peptidoglycan. The third resistant strain had a slightly thickened cell wall with an irregular, roughened outline; this strain also underwent autolysis on prolonged incubation on blood agar and the resistance may be associated with abnormal cell-wall synthesis. Sub-MIC concentrations of vancomycin and teicoplanin caused surface damage to a proportion of cocci able to grow in the presence of antibiotic. Exposure to teicoplanin was additionally associated with the formation of filamentous forms and variable amounts of extracellular material. Transmission electronmicroscopy showed that both antibiotics exerted effects within the bacterial cytoplasm of the resistant strains that were not seen in an NCTC control strain: intracellular lamellae and structures resembling mesosomes were observed in the former. These effects were more noticeable in cocci exposed to vancomycin. Bacteria exposed to teicoplanin often showed abnormal septation and, in some preparations, a double-layered cell wall.

Three-layered organic solar cell with a photoactive interlayer of codeposited pigments

Three-layered organic solar cell with an interlayer of codeposited pigments of n-type perylene tetracarboxylic derivative (Me-PTC) and p-type metal-free phthalocyanine (H2Pc) in between the respective pigment layers, was fabricated. Two times larger photocurrent compared to the double-layered cell without an interlayer was obtained due to the efficient carrier photogeneration in a codeposited layer. The power conversion efficiency reached 0.7% under the intense white light of 100 mW cm−2.

Morphological changes in putrefactive anaerobe 3679 (Clostridium sporogenes) induced by sorbate, hydrochloric acid, and nitrite.

Putrefactive anaerobe 3679 (Clostridium sporogenes), a gram-positive bacterium, was examined by light and electron microscopy during normal growth and in a medium containing sorbate (50 mM, pH 6.5), hydrochloric acid (pH of medium adjusted from 7 to 5 with HCl), or nitrite (1 mM, pH 7). During the early exponential growth phase, untreated cells were filamentous and nonseptate, but became septate later and divided when the culture entered the stationary phase. Untreated short and filamentous cells had a double-layered cell wall. Sorbate-treated cells were usually filamentous and nonseptate, but with distorted shapes characterized by numerous bends and bulges. Septation, when present, resulted in minicells. The inner cell wall appeared to be thickened and the outer wall was absent in many areas. Acid-treated cells were similar to sorbate-treated cells but contained septa. Considerable cellular debris was present in the suspension. Nitrite-treated cells were also filamentous, bent, and bulged but the cell wall appeared normal. Considerable cellular debris was also present in suspensions of nitrite-treated cells. Changes in morphology are discussed in relation to possible mechanisms of cell growth regulation and the inhibitory action of sorbate, acid, and nitrite.

New Asymmetrical Double-Layered Guest-Host Liquid Crystal Displays with Improved Optical Performances

Significant improvement of gray scale capability, faster response times, higher contrast ratio, and symmetrical display performance can be obtained in a new asymmetrical double-layered Guest-Host nematic liquid crystal cell geometry. A theoretical model describing the electro-optical performance in the principal viewing zone is shown.

Viewing Angle Characteristics of ECB Type Multi-Colored LCD with Non-Twist

Abstract A simplified analysis is made on the viewing angle characteristics of ECB type multicolored LCDs having no twist, under the assumption that the incident light beam is applied obliquely to the plane including the directors. In addition to making Δn. d small, a symmetric configuration of molecular orientation is found theoretically to be favorable for any applied voltages to improve the viewing angle characteristic. The symmetric configuration means a symmetry which is like a mirror image with respect to the midplane in the layer of a liquid crystal. This has been experimentally confirmed hy thc use of a double-layered cell having such symmetric configuration. In fact, the widest viewing angle range of ∼±40° has been obtained in a double-layered pretilted HAN cell. It is rcvcalcd cxperimentally that, when the incident light beam lies in the plane normal to the plane including the directors, the purity of displayed color tends to decrease in the cell having the symmetric configuration, as the incide...

Pancarditis in Whipple’s Disease: Electronmicroscopic Demonstration of Intracardiac Bacillary Bodies

The advent of electron microscopy has repeatedly confirmed Whipple's original postulate that bacterial infestation might be the cause of intestinal lipodystrophy (Whipple's disease). We have recently studied two patients, a 67-year-old man and a 38-year-old woman, who died of untreated Whipple's disease, and both were found to have clinically unrecognized pancarditis. Histologically, PAS-positive histiocytes in foci of chronic inflammation were demonstrable in several organs, including the heart. Electron microscopy of autopsy tissues showed numerous intracellular and extracellular rod-shaped bacillary bodies and serpiginous membranes. The bacillary bodies, some sectioned transversely and others longitudinally, were about 0.2 mum wide and 2 mum long; each had a double-layered cell wall. These bacillary bodies have not been previously identified in the heart, and may be casually related to cardiac lesions occurring in many untreated cases of Whipple's disease.

Electron Microscopic Observations of Chlamydia-like Microorganism in Hepatopancreas Cells of the Spider, Coras luctuosus

Chlamydia-like microorganism was observed not only in the cytoplasm but also within the intracytoplasmic inclusions of hepatopancreas cells of the spider, Coras luctuosus. The reticulate body, which bears a resemblance to that of members of the genus Chlamydia, is generally spherical and approximately 370 to 800mμ in diameter; its cytoplasm contains ribosome-like particles as well as fine DNA-like fibrils, and is bounded by a double-layered cell wall and a cytoplasmic membrane. The frequent occurrence of pairs or clusters of reticulate bodies and of profiles with symmetrical constriction, suggests that the reticulate bodies multiply by fission. Maturation process of the cell is accomplished by condensation of DNA-like fibrils. The elementary body is spherical, from 320 to 360mμ in diameter, with an eccentrically placed electron-dense nucleoid. In addition, four kinds of unusual parasites, which are undoubtedly cellular and procaryotic, are found only in the spider infected with the chlamydia-like microorganism. The possible relations of these parasites to the chlamydia-like microrganism are discussed.

Characteristics and properties of a caldo-active bacterium producing extracellular enzymes and two related strains.

The caldo-active strain YT-P was found to produce a variety of extracellular enzymes, including an amylase and a protease, which were further examined. With azo-casein as a substrate, optimum conditions with respect to enzyme and substrate concentration were determined for the protease. The optimum temperature was found to be 70°C, with a sharp decline to both lower and higher temperatures. The enzyme was found to be extremely heat-stabile, with unaltered activity after 8 hours at 80°C. Optimum conditions for the amylase were also examined. This enzyme was shown to be less heat-stabile, though the temperature optimum was again at 70°C. The activity or stability was not influenced by absence or presence of Ca-ions. The main activity of the amylase was found in the 20–40% ammonium sulfate fraction, which also contained the bulk of the proteolytic enzyme. This strain growth optimally on a variety of carbon sources at 72°C. Typical submicroscopical features are the double-layered cell wall, and a cytoplasmic membrane with a varying number of small dots and dot-free patches. Furthermore the nutritional requirements and submicroscopical features of two other strains, YT-G and YT-F, are described and compared to strain YT-P. Based on the fatty acid composition of the three spore forming caldo-active strains we suggest that they belong to the genus Bacillus, and propose the names B. caldolyticus for strain YT-P, B. caldovelox for strain YT-F, and B. caldotenax for strain YT-G.

Properties of a D-quinovosamine-producing Achromobacter.

The bacterial mucopolysaccharide of a Gram-negative bacterium, Georgetown strain COC-21, includes a hexosamine component, D-quinovosamine. The bacterium has been identified and classified as Achromobacter georgiopolitanum n. sp. and a description of the organism is given. The overall deoxyribonucleic acid base composition, determined by buoyant density measurements in cesium chloride, is 41 moles %. Electron micrographs of ultrathin sections reveal a double-layered cell wall structure typical of the Gram-negative bacteria.

ULTRASTRUCTURAL STUDIES ON THE CYANELLES OF GLAUCOCYSTIS NOSTOCHINEARUM ITZIGSOHN(1).

Ultrastructural studies conducted on the intracellular symbiont of Glaucocystis nostochinearum Itz., a unicellular alga with a debated taxonomic position, have shown that the endosymbiont, although somewhat aberrant, is a blue-green alga. Due possibly to its intracellular habitat, it lacks the characteristic cyanophycean double-layered cell wall and the cells appear to be completely naked, bound only by a single plasma membrane. The protoplasm of the cell is differentiated into the lamellated chromatoplasm, which contains the photosynthetic pigments and polyphosphate granules, and a nonlamellar ccntroplasm, in which the nucleic material is dispersed. The usual cyanophycean organelles, as well as the different vacuoles and granules, with the exception of the formed bodies, are missing. Approximately 10% of the cells sliows a peculiar homogeneous area at one tip, the nature of which is unknown. Binary fission of the organism is mentioned. Since this cyanelle has not yet been classified, we name it Skujapelta nuda nov. gen., nov. sp.; and because of its structural peculiarities we find it necessary to create a new family for it, Skujapeltaceae in the order Chroococcales.

ULTRASTRUCTURAL STUDIES ON THE BLUE-GREEN ALGAL SYMBIONT IN CYANOPHORA PARADOXA KORSCHIKOFF.

Studies conducted on the ultrastructure of Cyanophora paradoxa Korschikoff (a cryptomonad) have shown that its intracellular symbiont is closely related to unicellular blue-green algae. Due to its peculiar habitat, the intracellular symbiont lacks the characteristic cyanophycean double-layered cell wall, but is surrounded by a thin protoplasmic membrane. The protoplasm itself is differentiated into a lamellated chromatoplasm containing photosynthetic pigments, polyphosphate granules, and possible oil droplets, and a non-lamellar centroplasm with a large centrally located electron-opaque body surrounded by a fibril-containing halo. This halo-central body complex may be nuclear in nature. Binary fission of the organism is described. Since this cyanelle has not yet been classified, we name it Cyanocyta korschikoffiana nov. gen. nov. sp.; and because of its structural peculiarities, we find it necessary to create a new family for it, Cyanocytaceae, in the order Chroococcales.