scholarly journals Ultrastructural Features of an Abundant and Ubiquitous Marine Ciliate, Uronychia binucleata (Protista, Ciliophora, Euplotida)

2020 ◽  
Vol 7 ◽  
Author(s):  
Jingyi Dong ◽  
Xinpeng Fan ◽  
Tengyue Zhang ◽  
Saleh A. Al-Farraj ◽  
Thorsten Stoeck ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Ventral Side ◽  
Dorsal Side ◽  
Cortical Granules ◽  
Marine Ciliate ◽  
Transmission Electron ◽  
Membrane Bound ◽  
Few Data ◽  
Single Configuration ◽  
Electron Lucent

The ciliate genus Uronychia is a marine group with extremely differentiated cortical and ciliary structures. These structures define its unique evolutionary position in the whole subclass Euplotia. However, to date, few data about the ultrastructure of this genus and related taxa is available. In the present work, a dominant species, Uronychia binucleata, was investigated using scanning electron microscopy and transmission electron microscopy. The findings are as follows: (i) this species lacks the typical alveolar plate in its cortex, whereas the abundant electron-lucent vesicular structures occurred densely; (ii) the subpellicular microtubules form a triad configuration in the dorsal side, while appearing in a single configuration in the ventral side; (iii) the cortical granules are extrusomes, which represent a kind of mucocyst instead of ampules; (iv) two kinetosomes in different rows of one cirrus are linked by the single longitudinal connection; (v) the undulating membrane is highly developed and their insides and outsides are partially covered by the cortical flap; (vi) the single-membrane-bound pharyngeal disks interposed with microtubular sheets, and are distributed in three distinct zones. This first detailed report about the ultrastructural features of the genus Uronychia will be a key to improve the diagnosis and systematics of this widely distributed and ecologically important genus and its family Uronychiidae.

scholarly journals Infection With a Novel Rickettsiella Species in Emperor Scorpions (Pandinus imperator)

2020 ◽  
Vol 57 (6) ◽  
pp. 858-870
Author(s):  
Sushan Han ◽  
Aníbal G. Armién ◽  
Janet E. Hill ◽  
Champika Fernando ◽  
Dan S. Bradway ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Rapid Progression ◽  
Protein Coding ◽  
Hematopoietic Organ ◽  
Transmission Electron ◽  
History Of ◽  
Gross Lesions ◽  
Membrane Bound ◽  
Methenamine Silver

Rickettsiella infection was diagnosed in 4 adult emperor scorpions ( Pandinus imperator) from 2 different collections over a 3-year period. One case had a 2-day history of weakness, failure to lift the tail, or respond to stimulation, with rapid progression to death. The other 3 cases were found dead. There were no gross lesions, but histologically the hemolymphatic vasculature and sinuses, presumed hematopoietic organ, heart, midgut and midgut diverticula, nerves, and skeletal muscle were infiltrated with phagocytic and granular hemocytes with necrosis. Phagocytic hemocytes contained abundant intracellular microorganisms that were Fite’s acid-fast-positive, Macchiavello-positive, variably gram-positive or gram-negative, and Grocott’s methenamine silver-negative. By transmission electron microscopy, hemocytes contained numerous phagocytic vacuoles with small dense bacterial forms (mean 0.603 × 0.163 μm) interspersed with large bacterial forms (mean 1.265 × 0.505 μm) and few intermediary forms with electron-dense nucleoids and membrane-bound crystalline arrays (average 4.72 μm). Transmission electron microscopy findings were consistent with bacteria of the family Coxiellaceae. Based on sequencing the 16S ribosomal RNA gene, the identity was confirmed as Rickettsiella, and phylogenetic analysis of protein-coding genes gidA, rspA, and sucB genes suggested the emperor scorpion pathogen as a new species. This study identifies a novel Rickettsiella causing infection in emperor scorpions and characterizes the unique pathological findings of this disease. We suggest this organism be provisionally named Rickettsiella scorpionisepticum.

Phenethyl Isothiocyanate (PEITC) Regulates Autophagy in Chronic Lymphocytic Leukemia.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2906-2906
Author(s):  
Jemimah Adams ◽  
R Gitendra Wickremasinghe ◽  
Archibald G Prentice ◽  
Jonathan C. Strefford ◽  
Andrew Duncombe ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annexin V ◽  
Lymphocytic Leukemia ◽  
Phenethyl Isothiocyanate ◽  
Autophagosome Formation ◽  
Double Membrane ◽  
Transmission Electron ◽  
Membrane Bound ◽  
Autophagy Pathway

Abstract Abstract 2906 Chronic Lymphocytic leukemia (CLL) is currently incurable using conventional therapies. CLL cells can evade killing by various therapeutic strategies. However the precise mechanisms are currently unknown. Autophagy is regulated by a complex system of proteins, and is used by both normal and malignant cells as a protective mechanism against cellular stress induced by starvation, hypoxia, reactive oxygen species (ROS) and endoplasmic reticulum (ER) stress. In malignant cells autophagy was shown to promote tumorigenesis and/or resistance to chemotherapy. Therefore we hypothesized that autophagy may play a role in CLL biology. Autophagy can also promote cell death when stress signals are elevated above a particular threshold for a prolonged period of time. In this study we investigated the basal expression levels of autophagy specific genes and the effect of autophagy specific inhibitors (Bafilomycin, 3-methyladenine and hydroxychloroquine) and inducers (Phenethyl isothiocyanate) on CLL survival. Phenethyl isothiocyanate (PEITC) is about to enter clinical trials for CLL (NCT00968461). We have investigated induction of components of the autophagic pathway following treatment of CLL cells in vitro with a range of chemical inhibitors. Immunoblotting was carried out to investigate components of the autophagy pathway using phosphorylation state-specific and pan-reactive antibodies. Bafilomycin (BAF), 3-methyladenine (3-MA) and hydroxychloroquine (HCQ) toxicity towards CLL samples were evaluated by Annexin V/PI staining, MTT assay and immunoblotting for cleavage of the caspase 3 substrate poly(ADP ribose) polymerase (PARP) from its 116KDa to its 85KDa form. PEITC was used at concentrations between 2.5 and 25μM to investigate its effect on signaling. Autophagy was quantitated by immunoblotting of LC3-I and LC3-II. Lipidation of LC3 from LC3-I to LC3-II is a surrogate marker of autophagy and is essential for autophagasome formation. Immunoblotting was also performed for ATG3, ATG5 and ATG7, key components of the autophagy pathway. Monodansylcadaverine (MDC) was used with immunofluorescence and FACS analysis to investigate increases in autophagasome formation. Transmission electron microscopy (TEM) was used to confirm double membrane bound autophagosomes. Co-immunoprecipitation was used to evaluate if Beclin-1 was sequestered by Bcl-2 preventing autophagy. Its release from Bcl-2 enables Beclin-1 to interact with other autophagy specific proteins and initiates autophagasome formation. LC3-I was lipidated to LC3-II (p=0.019) and ATG3 (p=0.021) was upregulated to a greater extent in CLL samples compared with normal B-cell controls at basal levels. This suggested that autophagy was active to a greater extent in CLL samples compared with normal individuals. In addition Beclin was dissociated from Bcl-2 in CLL samples indicating that autophagy was active. Autophagy appears to be a pro-survival mechanism in untreated CLL cells as inhibiting basal levels of autophagy with autophagy inhibitors BAF (50–200nM), 3-MA (5–10mM) and hydroxychlorquine (5–10μM) resulted in CLL apoptosis as shown by MTT, Annexin V/PI analysis and PARP cleavage. Interestingly augmenting autophagy was also capable of inducing apoptosis in CLL samples. Treatment with PEITC caused an increase in punctate staining using MDC which is suggestive of autophagosome formation. We went on to determine that PEITC further induced LC3-II lipidation using immunoblotting and showed a substantial increase in overall LC3 protein expression. PEITC also induced the expression of ATG3, a key protein in the autophagy pathway. We then evaluated autophagosome formation using TEM (Figure 1). Our data showed greater numbers of autophagosomes in the PEITC treated samples compared to the untreated controls. Therefore autophagy in CLL sits on a knife-edge, such that perturbations that either increase pro- death or decrease pro-survival autophagy signals can result in CLL cell death, depending on the duration and intensity of the signal. Figure 1. Transmission electron microscopy of CLL cells CLL cells were treated with 10μM PEITC. Double membrane bound organelles were found in the CLL cells after treatment which were not present in the no addition control (depicted by the arrows). These organelles are autophagsomes. Magnification (left picture) ruler is 500nM, (right picture) ruler is 100nM Figure 1. Transmission electron microscopy of CLL cells . / CLL cells were treated with 10μM PEITC. Double membrane bound organelles were found in the CLL cells after treatment which were not present in the no addition control (depicted by the arrows). These organelles are autophagsomes. Magnification (left picture) ruler is 500nM, (right picture) ruler is 100nM Disclosures: No relevant conflicts of interest to declare.

The comparative ultrastructure of spermatozoa from Bothrimonus sturionis Duv. 1842 (Pseudophyllidea), Pseudanthobothrium hanseni Baer, 1956 (Tetraphyllidea), and Monoecocestus americanus Stiles, 1895 (Cyclophyllidea)

1984 ◽  
Vol 62 (6) ◽  
pp. 1059-1066 ◽  
Author(s):  
Barbara M. MacKinnon ◽  
Michael D. B. Burt
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Plasma Membrane ◽  
Main Body ◽  
Posterior Portion ◽  
Transmission Electron ◽  
Dense Nucleus ◽  
Comparative Ultrastructure ◽  
Electron Lucent ◽  
Mature Spermatozoa

The mature spermatozoa from Bothrimonus sturionis (Pseudophyllidea), Pseudanthobothrium hanseni (Tetraphyllidea), and Monoecocestus americanus (Cyclophyllidea) were examined using transmission electron microscopy. Transverse sections of the sperm of B. sturionis indicate that the number of sperm axonemes varies from one to eight, with approximately one-third of the sperm containing two axonemes. Likewise, the number of peripheral microtubules lying just within the external plasma membrane varies from 12 to 20. The nucleus is electron lucent and fibrous in appearance. The spermatozoa of B. sturionis show great variation in the material examined and the majority of them are believed to be aberrant. The spermatozoon of P. hanseni contains a single axoneme with the nucleus wrapped in a crescent around it in the anterior region of the sperm. The posterior portion of the spermatozoon is characterized by a helical flange which projects from the main body of the sperm. The spermatozoon of M. americanus is elongate and slender, containing a single axoneme with an electron-dense nucleus coiled around it in the anterior one-third of the sperm. Electron-opaque bodies, which may be glycogen, fill the cytoplasm. The spermatozoa of all three species contain neither an acrosome nor mitochondria. The flagella of all the spermatozoa have a 9 + "1" arrangement of microtubules. The importance of the ultrastructure of spermatozoa in the phylogeny and taxonomy of cestodes is discussed.

The ultrastructure of the skeleton and skeletogenic tissues of the temperate coral Caryophyllia smithii

1990 ◽  
Vol 70 (2) ◽  
pp. 295-310 ◽  
Author(s):  
Martin D'A.A. Le Tissier
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Organic Matrix ◽  
Secretory Vesicles ◽  
Intercellular Spaces ◽  
Transmission Electron ◽  
Temperate Coral ◽  
Zooxanthellate Coral ◽  
Membrane Bound ◽  
Calicoblastic Ectoderm

The skeleton and calicoblastic ectoderm of the scleractinian non-zooxanthellate coral Caryophyllia smithii were investigated by light microscopy, scanning and transmission electron microscopy. Except for some costal spines, the skeleton was fasciculate. Fasciculi were made up of bundles of crystalline needles, each crystalline needle consisting of a number of linear series of small (<1 μm) rounded crystals. Fractured skeletons showed the fasciculi to be arranged into layers and that within some septa, theca and costal spines there were spaces that contained neither mineral nor organic matter. These spaces could also be found at the growing edges of septa and theca. Demineralization of the skeleton revealed an organic matrix whose configuration mirrored the architecture of the skeleton. In areas of the skeleton where deposition was occurring the overlying calicoblastic ectoderm was relatively thin with prominent intercellular spaces and secretory vesicles. In contrast, over non-depositing areas the calicoblastic ectoderm was thick and contained residual bodies, nematocysts and membrane-bound granules. The results are compared and contrasted with those from scleractinian corals that have endosymbiotic zooxanthellae.

scholarly journals Integumentary Histology of the Amphibious Blenny, Isteblennius edentulus (Forester and Schneider, 1801)

2009 ◽  
Vol 14 ◽  
pp. 9
Author(s):  
Taher Ba-Omar ◽  
Maisoon M. Al-Riyami
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Gas Exchange ◽  
Epithelial Cells ◽  
Surface Area ◽  
Ventral Side ◽  
Dorsal Side ◽  
Scanning Electron

The skin of the amphibious blenny, Istiblennius edentulus, was studied using both light and scanning electron microscopy. Rich vascularisation was found immediately below the epidermis and the dermis. Surface epithelial cells displayed microridges in a fingerprint-like pattern.  It was speculated that this increased surface area may aid in the adhesion of mucous secretions as well as to increase the surface area for gas exchange. The number of pores on the dorsal side (6.3x103 per mm2) was significantly higher than that on the ventral side (4.3x103 per mm2). The thickness of the skin on the dorsal side was measured at 31.6±10.0µm and that on the ventral side was 32.9 ± 7.8µm.  

scholarly journals FRTL-5 Rat Thyroid Cells Release Thyroglobulin Sequestered in Exosomes: A Possible Novel Mechanism for Thyroglobulin Processing in the Thyroid

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Pavel Vlasov ◽  
Sonia Q. Doi ◽  
Donald F. Sellitti
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Western Blotting ◽  
Thyroid Stimulating Hormone ◽  
Cellular Proteins ◽  
Thyroid Cells ◽  
Normal Thyroid ◽  
Transmission Electron ◽  
Membrane Bound ◽  
Rat Thyroid

Exosomes are 30–100 nm, membrane-bound vesicles containing specific cellular proteins, mRNAs, and microRNAs that take part in intercellular communication between cells. A possible role for exosomes in thyroid function has not been fully explored. In the present study, FRTL-5 rat thyroid cells were grown to confluence and received medium containing either thyroid stimulating hormone (TSH), exogenous bovine thyroglobulin (bTg), or neither additive for 24 or 48 hours followed by collection of spent medium and ultracentrifugation to isolate small vesicles. Transmission electron microscopy and Western blotting for CD9 indicated the presence of exosomes. Western blotting of exosome extract using a monoclonal anti-Tg antibody revealed a Tg-positive band at ~330 kDa (the expected size of monomeric Tg) with a higher density in TSH-treated cells compared to that in untreated cells. These results are the first to show that normal thyroid cells in culture produce exosomes containing undegraded Tg.

scholarly journals Effect of microtrichia on the interlocking mechanism in the Asian ladybeetle, Harmonia axyridis (Coleoptera: Coccinellidae)

2018 ◽  
Vol 9 ◽  
pp. 812-823 ◽  
Author(s):  
Jiyu Sun ◽  
Chao Liu ◽  
Bharat Bhushan ◽  
Wei Wu ◽  
Jin Tong
Keyword(s):  
Electron Microscopy ◽  
Harmonia Axyridis ◽  
Environmental Scanning Electron Microscopy ◽  
Micro Air Vehicles ◽  
Underlying Mechanism ◽  
Ventral Side ◽  
Dorsal Side ◽  
Environmental Scanning ◽  
Locking Mechanism ◽  
Scanning Electron

The hindwings of beetles are folded under the elytra when they are at rest but are extended during flight, which can provide bioinspiration for the design of deployable micro air vehicles (MAVs). Beetle hindwings must be able to be both securely locked under the elytra and freely extended for flight, depending on the required action. To investigate the locking mechanism, this study used environmental scanning electron microscopy (ESEM) to examine the microstructures of the elytra, hindwings and abdomen of the Asian ladybeetle, Harmonia axyridis (Pallas, 1773). On the ventral side (VS) of the elytra, the microtrichia show a transitional structure from the lateral edge to the medial edge. On the hindwing surface, the folded regions were observed on both the dorsal side (DS) and the VS. On the abdomen, the microtrichia between the abdominal segments show a cyclical change from sparse to dense in each segment in the middle of the abdomen. Furthermore, the different directions of microtrichia that lead to self-locking friction on the surfaces of the hindwing, elytron and abdomen appear to facilitate interlocking. A model for the interlocking of the hindwings of the H. axyridis was established, and its underlying mechanism is discussed.

Vitellocyte ultrastructure in the cestode Didymobothrium rudolphii (Monticelli, 1890): possible evidence for the recognition of divergent taxa within the Spathebothriidea

2006 ◽  
Vol 51 (4) ◽  
Author(s):  
Larisa Poddubnaya ◽  
David Gibson ◽  
Zdzisław Świderski ◽  
Peter Olson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Lipid Droplets ◽  
Interstitial Tissue ◽  
Morphological Parameters ◽  
Transmission Electron ◽  
Shell Globule ◽  
Didymobothrium Rudolphii ◽  
First Time ◽  
Electron Lucent

AbstractIn the spathebothriidean tapeworm Didymobothrium rudolphii (Monticelli, 1890) the fine structure of the vitellocytes at different stages of their development within the vitelline follicles, vitelline ducts and uterus was studied for the first time using transmission electron microscopy. The vitellocyte inclusions of D. rudolphii are shell globule clusters containing tightly packed shell globules associated with a matrix of moderate electron density, glycogen granules, large electron-lucent lipid droplets (up to 3 μm in diameter), and, occasionally, a lipid droplet may occur in the nucleus of the vitellocytes. The diameter of the clusters ranges from 0.4 to 2.5 μm, the number of shell globules in the clusters varies from 8 to 45, and the size of the globules ranges from 0.12 to 0.25 μm and they are of approximately homogeneous sizes within a cluster. Most vitellocyte lipid droplets have a heterogeneous configuration with a ‘cavity’ inside them when they are within vitelline ducts and intrauterine eggs. Vitellocytes of the eggs contain dark concentric bodies and lipid droplets. The interstitial tissue has a syncytial structure. The morphological parameters of the diameter and shape of shell globule clusters, arrangement of shell globules in clusters, number and diameter of globules within clusters, types of lipid droplets and presence of dark concentric bodies are compared with those of two other spathebothriidean genera, Cyathocephalus and Diplocotyle. The comparative data demonstrate that vitelline material morphology has unique features in three spathenothriidean genera and may be used as evidence for the recognition of separate taxa.

scholarly journals Evolution of glandular structures on the scape of males in the genus Aphelinus Dalman (Hymenoptera, Aphelinidae)

2019 ◽  
Vol 72 ◽  
pp. 27-43
Author(s):  
Xanthe A. Shirley ◽  
James B. Woolley ◽  
Keith R. Hopper ◽  
Nunzio Isidoro ◽  
Roberto Romani
Keyword(s):  
Electron Microscopy ◽  
Mate Recognition ◽  
Ventral Side ◽  
Parasitoid Wasps ◽  
Aphytis Melinus ◽  
Species Complexes ◽  
Transmission Electron ◽  
Outgroup Species ◽  
Glandular Structures ◽  
Aphelinus Varipes

The pores and associated glands on male antennae in species of Hymenoptera are involved in mate recognition and are diverse and widespread among taxa. However, nothing has been published about these structures in species of Aphelinus (Chalcidoidea: Aphelinidae), a genus of parasitoid wasps with a long history in biological control. Images from scanning electron microscopy (SEM) and transmission electron microscopy (TEM) of Aphelinus varipes revealed pores on the ventral side of the male scape that were connected to glands. A survey of the scapes of male antennae in 16 species in six species complexes of Aphelinus, as well as two outgroup species, Aphytis melinus and Centrodora sp., showed that pores were present in all except Centrodora sp. The pores varied in several characters: the shape of the structures that carried them, pore size, elevation of the cuticle surrounding the structures, the extent of a carina delimiting the area around the structures, and the number and position of pores. The shape of the pore-bearing structures, the elevation of cuticle around these structures, and the extent of the carina around them map well onto a molecular phylogeny of these Aphelinus species. Combinations of pore characters are diagnostic of species complexes, and in some cases, species of Aphelinus.

scholarly journals A modified lysosomal organelle mediates nonlytic egress of reovirus

2020 ◽  
Vol 219 (7) ◽  
Author(s):  
Isabel Fernández de Castro ◽  
Raquel Tenorio ◽  
Paula Ortega-González ◽  
Jonathan J. Knowlton ◽  
Paula F. Zamora ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electron Tomography ◽  
Microvascular Endothelial Cells ◽  
Brain Microvascular Endothelial Cells ◽  
Basal Surface ◽  
Reovirus Infection ◽  
Transmission Electron ◽  
Membrane Bound ◽  
Viral Inclusions ◽  
Virus Egress

Mammalian orthoreoviruses (reoviruses) are nonenveloped viruses that replicate in cytoplasmic membranous organelles called viral inclusions (VIs) where progeny virions are assembled. To better understand cellular routes of nonlytic reovirus exit, we imaged sites of virus egress in infected, nonpolarized human brain microvascular endothelial cells (HBMECs) and observed one or two distinct egress zones per cell at the basal surface. Transmission electron microscopy and 3D electron tomography (ET) of the egress zones revealed clusters of virions within membrane-bound structures, which we term membranous carriers (MCs), approaching and fusing with the plasma membrane. These virion-containing MCs emerged from larger, LAMP-1–positive membranous organelles that are morphologically compatible with lysosomes. We call these structures sorting organelles (SOs). Reovirus infection induces an increase in the number and size of lysosomes and modifies the pH of these organelles from ∼4.5–5 to ∼6.1 after recruitment to VIs and before incorporation of virions. ET of VI–SO–MC interfaces demonstrated that these compartments are connected by membrane-fusion points, through which mature virions are transported. Collectively, our results show that reovirus uses a previously undescribed, membrane-engaged, nonlytic egress mechanism and highlights a potential new target for therapeutic intervention.

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