bluuebunny/crossref_metadata_2025_split huggingface dataset:
Virus-Like and Membrane-Bound Particles in the Venom Apparatus of a Parasitoid Wasp (Hymenoptera:Braconidae)
Authors: Edson Karthryn M. 
Published: June 2020

Successful parasitism of a host by a parasitoid wasp may be aided by secretions from the venom apparatus, an accessory gland of the female parasitoid's reproductive system. In the present study, transmission electron microscopy of the venom apparatus of Meteorus leviventris reveals virus-like and membrane-bound particles which may influence successful parasitism of the host. This is the first evidence of such particles within the venom apparatus of a parasitoid.The venom apparatus of M. leviventris consists of a venom reservoir with two highly ramified gland filaments attached to it by a common duct.TEM of the secretory cells of the gland filaments reveals particles approximately 50 nm in diameter contained within a cytoplasmic stroma (Fig. 1). These virus-like particles (VLP) have a dense inner core and a hexagonal congifuration. Similar particles are found free within the cytoplasm or associated with vacuoles (Fig. 2).Secretory cells of the gland filaments contain a secretory apparatus which consists of an array of microvilli converging on a central lumen (Fig. 3).
New Ultrastructural Observations on Injury and Regeneration of Cilia in Mammalian Conducting Airway Epithelium
Authors: Carson J.L. , Collier A.M. 
Published: June 2020

The ciliated cells lining the conducting airways of mammals are integral to the defense mechanisms of the respiratory tract, functioning in coordination with secretory cells in the removal of inhaled and cellular debris. The effects of various infectious and toxic agents on the structure and function of airway epithelial cell cilia have been studied in our laboratory, both of which have been shown to affect ciliary ultrastructure.These observations have led to questions about ciliary regeneration as well as the possible induction of ciliogenesis in response to cellular injury. Classical models of ciliogenesis in the conducting airway epithelium of the mammalian respiratory tract have been based primarily on observations of the developing fetal lung. These observations provide a plausible explanation for the embryological generation of ciliary beds lining the conducting airways but do little to account for subsequent differentiation of ciliated cells and ciliogenesis during normal growth and development.
Fine Structural Localization of Membrane ATPase Activity in the Choroid Plexus and Ependyma of the Guinea Pig
Authors: Beggs John 
Published: June 2020

It is generally accepted that the choroid plexus plays an active role in the formation of cerebrospinal fluid. Present evidence suggests that its specific function is to transport sodium into the ventricular cavity. Since membrane-bound ATPase has been implicated in cation transport in various cells and tissues, this study was designed to localize this activity in the choroid as well as the ependyma at the ultrastructural level.The final reaction product resulting from hydrolysis of ATP in the Wachstein-Meisel media was deposited at specific sites along the plasmalemmata (no deposits occurred when B-glycerophosphate was substituted, or when ATP was omitted from the incubation media). In the choroid, reaction product at the apical surface was found to have a random pattern on: a) microvilli and cilia, b) on the plasmalemma between microvilli, c) within coated vesicles at and near the surface (Fig. 1). Lateral membranes and their inter-digitations showed sparse reaction product. The highest activity was exhibited at the basal plasmalemma where deposits followed a uniform pattern along cytoplasmic infoldings and vacuoles (Fig. 2).
Cytochemistry of Membrane-Associated Cytochrome Oxidase in Azotobacter Vinelandii
Authors: Gardner J. N. , Lin L. P. , Socolofsky M. D. 
Published: June 2020

Young, vegetative cells of the nitrogen-fixing bacterium, Azotobacter vinelandii, contain invaginations of the cytoplasmic membrane. These typical procaryotic cells are characterized by the absence of both a nuclear membrane and organelles such as Golgi bodies and mitochondria (Fig. 1). Although mitochondria are the organelles responsible for electron transport and respiratory operations in eucaryotic organisms, the electron transport function of procaryotic cells is attributed to the membranous structures. In the present study an attempt was made to visualize the site of cytochrome oxidase activity using methods of cytochemistry and electron microscopy.The classical method for the demonstration of cytochrome oxidase activity is the Nadi reaction; the two reagents of this reaction are 1-naphthol and p-phenylenediamine. A substituted p-phenylenediamine, N-benzyl-p-phenylenediamine (BPDA), was used successfully by Seligman et al in the demonstration of cytochrome oxidase activity. This reagent reacts readily with 1-naphthol to form an osmiophilic quinoneimine group resulting in the transfer of electrons to cytochrome c which is subsequently oxidized by cytochrome oxidase. The quinoneimine group reacts with OSO4 to yield an electron dense pigment at the site of cytochrome oxidase activity.
Fine Structure of Bacteria Grown in the Presence of Acriflavine
Authors: Boatman Edwin S. 
Published: June 2020

The effect of acridine derivatives on bacterial growth has been shown to be dependent upon the concentration used, pH, temperature, and the position of the amino substituents on the acridine molecule. These factors, in turn, affect the amount of acridine bound to cell constituents. Many bacterial species, when grown in media containing acridities, become filamentous, or pleomorphic, or growth may be entirely prevented. The fine-structure of two species of bacteria treated with acriflavine was investigated. Both were Gram-positive bacilli, one was a Corynebacterium, and the other an aerobic spore-bearing Bacillus.Organisms were incubated at 21°c in the presence of concentrations of acriflavine ranging from 0.25 ug/ml to 12 ug/ml in phosphate buffered peptone water yeast extract medium at pH 7.5. Viable counts were carried out and the amount of acriflavine bound, either reversibly or irreversibly, was estimated at 450 mu, using a DB spectrophotometer. Cultures were observed by light microscopy and, after four days growth, were processed for electron microscopy by fixation in veronal-acetate pH 6.1 buffered 0.8% Os O4 for one hour and embedding in Epon 812 resin.
Nucleolar Segregation in Cells of Untreated Mouse Lymph Node
Authors: Arnold Wm. James , Albert S. 
Published: June 2020

Certain cells which often form prominent populations in mouse lymph nodes have the morphological characteristics of, and parallel the development of, young erythroid cells. These cells produce no histochemically detectable amounts of hemoglobin and bear no indication of full-scale nuclear extrusion. Their nucleoli persist beyond the state of development at which nucleoli disappear from erythroid cells of the bone marrow and spleen. In their persistence, these nucleoli display a structure which is very similar to the “segregation” often found in nuclear intoxication.Profiles of these nucleoli seen in electron micrographs lie usually in contact with condensed chromatin and often appear to be completely surrounded by it (Figure 1). They have the internal appearance of being made up of two or three discrete components each separate from the others. The outer layer is composed of granules about the size and shape of cytoplasmic ribosomes, packed together to an extent intermediate between the interchromatin and the chromatin (Figure 2). Inside the granular shell there are one or several aggregations of fibrillar material, often forming a circular profile (Figure 2). In most nucleoli a third component is present and consists of clusters of darkly staining granules similar to the chromatin but lying within the nucleolus, frequently at the interface of the other components (Figure 3).
Investigation of the Origin of the Crystal Containing Cell in the Caecal Epithelium of the Mouse
Authors: Wesley R. K. Anthony , Jensen Thomas E. 
Published: June 2020

The crystal containing cell has been found in portions of the large and small intestine of the mouse. The cells are usually located at the basal aspect of the epithelium and contain intracytoplasmic inclusions which demonstrate a 60 A lamellar periodicity (Fig. 1) when the plane of sectioning is perpendicular to the crystal lattice. The purpose of this study is to determine if the crystal containing cells are of true epithelial origin or if they originate from a migratory cell type which enters the epithelium from the lamina propria and then differentiates.12 mice were administered intraperitoneal injections of actinomycin D in the following divisions: Group I, 23 ug actinomycin D during a 24 hour period; Group II, 33 ug during 48 hours; Group III, 40 ug over 52 hours; and Group IV, 63 ug over 72 hours. Examination of the caecal epithelia with the electron microscope revealed an increase in the number of crystal containing cells in the treated animals (Fig. 3) over the controls which were injected with corresponding amounts of physiological saline. Control epithelia have crystal cells in about 1-2% of the total cell population, whereas the treated mice epithelia have crystal cells in approximately 20%, or more of the total cells. A large number of migratory cells may have invaded the intestine in response to the peritoneal inflammation established during actinomycin D administration. The increased number of crystal cells in treated mice probably developed from the increased migratory cell population. Since low levels of actinomycin inhibit mitoses in mammalian cell lines, the increase in the number of crystal containing cells in the epithelium could not have been from divisions of the pre-existing cells originally present in the epithelium.
Scanning Microscopy of Human Blood and Marrow Smears
Authors: McDonald L. W. , Hayes T. L. 
Published: June 2020

The scanning electron microscope (SEM) permits direct observation of standard light microscope slide and cover slip preparations. Single cells can be located and identified in the two instruments and the higher resolution, three dimensional image of the SEM can be correlated with the classic cytological information contained in the light microscope image.Samples of peripheral blood and bone marrow were obtained from patients with chronic lymphatic leukemia and polycythemia. A drop of either blood or bone marrow from the syringe used for drawing the specimen was placed on alcohol cleaned, 22 mm square cover glasses. A second cover glass was placed over the drop of blood or marrow and the two cover glasses drawn apart in the manner usual for preparing blood and marrow for examination by light microscopy. These cover slips were rapidly air dried and then stained for examination by light microscopy. The staining procedure consisted of flooding the cover glass with Jenner's stain for 5 minutes, adding distilled water to cover the glass for another 5 minutes and then washing in tap water. Following this a Giemsa stain made up freshly from the stock solution was applied to the cover glass for 10 minutes. The cover glass was then washed and air dried. A thin coating of platinum-paladium was applied in a vacuum evaporator to facilitate electrical conduction.
Incomplete Maturation of Iridal Pigment in Heterochromia Iridum
Authors: Shively James N. , Phemister Robert D. 
Published: June 2020

Heterochromia is an abnormality of iridal pigmentation characterized by marked differences in the color of the two irides or in segments of one iris. The affected areas are pale blue to grayish white. The condition is known to be present in a variety of species including man, dog, mouse, rabbit, cat, pig, and horse. In some species heterochromia has been transmitted as an autosomal dominant trait. It is also a dominant characteristic in Waardenberg's oculo-dermato-auditive syndrome. In several breeds of dogs heterochromia is associated with merle (or harlequin or dappled) coat color which is controlled by an autosomal dominant gene. Other factors are involved in Fuch's heterochromic cyclitis.The present study resulted from the spontaneous occurrence of 5 cases of heterochromia in a large colony of beagles produced to study the long-term effects of low doses of radiation administered at various ages. When ten weeks old (3 or 4 weeks after the dog eye has attained adult characteristics), the affected dogs were anesthetized with pentobarbital sodium. The eyes were extirpated and quickly hemisected dorsoventrally. One calotte was fixed in cold glutaraldehyde-acrolein for 90 minutes. Representative blocks through the iris were cut and stored in phosphate buffer (pH 7. 3) overnight, washed in veronal-acetate buffer, pH 7.3, and post-fixed in 2% OsO4 in veronal-acetate buffer. Further processing was by standard techniques. The sections were stained with uranyl acetate and lead citrate. The other calotte was fixed for 24 hours in 6.25% glutaraldehyde for light microscopy. The calotte was rinsed in phosphate buffer, pH 7.3., embedded in paraffin, sectioned at 6μ and stained with hema-toxylin and eosin.
Intestinal Absorptive Epithelium in Wolman's Cholesterol Lipidosis
Authors: Partin John C. , Mereu Tullio R. , Schubert William K. 
Published: June 2020

Wolman's cholesterol lipidosis is a rare genetic disorder of lipid metabolism in which large amounts of chemically normal cholesterol and triglyceride are accumulated in tissues, particularly liver, spleen, skin, adrenal and intestine. Affected infants develop vomiting, diarrhea, wasting and enlargement of the liver and spleen during the first weeks of life. Characteristic enlargement and calcification of the adrenal glands are present by x-ray. Most of the children die in early infancy.This is the first report of electron microscopy (EM) of small intestinal absorptive epithelium in Wolman's disease. Mucosa was obtained by peroral biopsy from a 6 month old affected infant. The tissue was divided and prepared for lipid staining in frozen sections and for electron microscopy. Lipid stains demonstrated large amounts of lipid in the absorptive but not the crypt epithelium. Serial sections were made of the osmium fixed villi through the absorptive epithelium. Remarkable EM changes were present in thelysosomes, thesmooth endoplasmic reticulumand theGolgi system: Lysosomal vacuoles below the terminal web contained large amounts of dense material as well as electron “lucent” crystal-like images, possibly cholesterol or its esters. Smooth endoplasmic reticulum was prominent and contained many osmiphilic droplets. In the ectoplasm near the plasma membrane great cylindrical whorls of crinkled membrane seemed to arise in association with smooth endoplasmic reticulum, frequently wound around a mitochondrion. In the Golgi system, peripheral vesicles were distended with uniform droplets about. μ in diameter resembling chylomicrons.
Comparison of Normal and Thrombasthenic Human Blood Platelets
Authors: Rodman N. F. , Painter J. C. , Mason R. G. 
Published: June 2020

The ultrastructure of normal human blood platelets in the resting state has been described in detail. Platelets recovered from citrated plasma of a patient with Glanzmann's thrombopathy or thrombasthenia have a similar appearance (Fig. 1). These anucleate cells are usually disc shaped and hence are round or oval, depending upon the plane of sectioning. They have randomly dispersed cytoplasmic organelles and microtubules which are typically arranged in a marginal band.Platelet responses to several agglutinating agents and the relation of platelets to fibrin during clotting have been reported. On exposure to thrombin, to ADP, or to collagen, normal and thrombasthenic platelets undergo similar early morphologic changes. Pseudopods form and organelles move toward platelet centers, with microtubules being outermost of the closely packed, centrally apposed organelles. A peripheral rim of cytoplasm is essentially organelle-free except for an occasional mitochondrion or vacuole and except for microtubules which sometimes extend outward into pseudopods. Following these early, preagglutination changes normal platelets agglutinate in response to each of the 3 agglutinating agents, whether in autologous plasma or in salt solution after repeated washings. Thrombasthenic platelets in autologous plasma fail to agglutinate in response to thrombin or to ADP and agglutinate only minimally on exposure to finely divided collagen.
Biological and Morphological Studies on Low-Leukemia-Strain Mice with Hodgkin's-Like Neoplasia Induced by Serial Cell-Free Transmission of Leukemic Organs of SJL/J Strain Mice
Authors: Fujinaga S. , Maruyama K. , Williams C.W. , Sekhri K. , Dmochowski L. 
Published: June 2020

Yumoto and Dmochowski (Cancer Res.27, 2098 (1967)) reported the presence of mature and immature type C leukemia virus particles in leukemic organs and tissues such as lymph nodes, spleen, thymus, liver, and kidneys of SJL/J strain mice with Hodgki's-like disease or reticulum cell neoplasm (type B). In an attempt to ascertain the possibility that this neoplasia may be of viral origin, experiments with induction and transmission of this neoplasm were carried out using cell-free extracts of leukemic organs from an SJL/J strain mouse with spontaneous disease.It has been possible to induce the disease in low-leukemia BALB/c and C3HZB strain mice and serially transfer the neoplasia by cell-free extracts of leukemic organs of these mice. Histological examination revealed the neoplasia to be of either reticulum cell-type A or type B. Serial transfer is now in its fifth passage. In addition leukemic spleen from another SJL/J strain mouse with spontaneous reticulum cell neoplasm (type A) was set up in tissue culture and is now in its 141st serial passage in vitro. Preliminary results indicate that cell-free material of 39th tissue culture passage can reproduce neoplasia in BALB/c mice.
A Versatile, Sensitive Photometer For Electron and Optical Micrography
Authors: Drogosz F. B. , Hungerford W. R. , Bigelow W. C. 
Published: June 2020

Many electron microscopes manufactured during the last decade were not equipped with exposure meters. The addition of exposure meters to these instruments greatly increases their efficiency and effectiveness. The photometer described here was developed particularly for this purpose and has been used for a number of years with highly satisfactory results. It is, however, quite versatile and, with appropriate modifications, has been found equally satisfactory for use in macro- and microphotography, photographic enlarging, turbidimetry, etc.This photometer uses the simple triode cathode-follower circuit shown in Fig. 1 to amplify the response of an inexpensive CdS-SdSe type photocell whose electrical resistance Rc decreases with increasing intensity of illumination. In this circuit, the meter reads the cathode current of the troide which is controlled by the voltage Eg applied to its grid. The grid is connected to a voltage divider composed of the photocell and two sensitivity adjusting resistors Rs, so that Eg = VRc/(Rc + Rs).
Further Ultrastructural Observations on Metastatic Nodules of Human Breast Cancer
Authors: Swedo John L. , Talley R. W. , Watson John H. L. 
Published: June 2020

Since the report, which described the ultrastructure of a metastatic nodule of human breast cancer after estrogen therapy, additional ultrastructural observations, including some which are correlative with pertinent findings in the literature concerning mycoplasmas, have been recorded concerning the same subject. Specimen preparation was identical to that in.The mitochondria possessed few cristae, and were deteriorated and vacuolated. They often contained particulates and fibrous structures, sometimes arranged in spindle-shaped bundles, Fig. 1. Another apparent aberration was the occurrence, Fig. 2 (arrows) of linear profiles of what seems to be SER, which lie between layers of RER, and are often recognizably continuous with them.It was noted that the structure of the round bodies, interpreted as within autophagic vacuoles in the previous communication, and of vesicular bodies, described morphologically closely resembled those of some mycoplasmas. Specifically, they simulated or reflected the various stages of replication reported for mycoplasmas grown on solid nutrient. Based on this observation, they are referred to here as “mycoplasma-like” structures, in anticipation of confirmatory evidence from investigations now in progress.
Freeze-Etching of Intercellular Junctions of Mouse Liver
Authors: Kreutziger G. O. 
Published: June 2020

The tight junction at the bile canniculus of mouse liver contains a packed hexagonal particle array in the intercellular space. This region has been identified in freeze-etch preparations revealing several additional structures.Mouse liver is fixed in 2% purified glutaraldehyde for 2 hours and infiltrated with 20% glycerine for 1/2 hour. Fixative and cryoprotective solutions are prepared in sodium-free Krebs-Ringer phosphate pH 7.2 to 7.4 and the solutions are oxygenated before use. Fixation and infiltration are conducted at room temperature prior to quick freezing in liquid propane. Freeze-etch replicas are produced with a modified simple freeze-etch device, cleaned with “Clorox”, washed with distilled water and examined unsupported on 300 mesh grids in a Seimens Elmiskop 1A.Two different views of the Plasmalemma are observed (Fig.1). The intercellular surface is identified by the hexagonal particle array. Outside the tight junction this surface has a dense randomly distributed particle population. Viewed from the intracellular surface a circumscribed area reflects the closer membrane apposition of the occluding junction.
Voids in Quenched Nickel
Authors: Laidler J. J. 
Published: June 2020

The presence of three-dimensional voids in quenched metals has long been suspected, and voids have indeed been observed directly in a number of metals. These include aluminum, platinum, and copper, silver and gold. Attempts at the production of observable quenched-in defects in nickel have been generally unsuccessful, so the present work was initiated in order to establish the conditions under which such defects may be formed.Electron beam zone-melted polycrystalline nickel foils, 99.997% pure, were quenched from 1420°C in an evacuated chamber into a bath containing a silicone diffusion pump fluid . The pressure in the chamber at the quenching temperature was less than 10-5 Torr . With an oil quench such as this, the cooling rate is approximately 5,000°C/second above 400°C; below 400°C, the cooling curve has a long tail. Therefore, the quenched specimens are aged in place for several seconds at a temperature which continuously approaches the ambient temperature of the system.