scholarly journals Structure and ultrastructure of oogenic stage in short mackerel Rastrelliger brachysoma (Teleostei: Scombidae)

2017 ◽  
Vol 34 (01) ◽  
pp. 023-030
Author(s):  
S. Senarat ◽  
J. Kettratad ◽  
W. Jiraungkoorskul
Keyword(s):  
Lipid Droplets ◽  
Growth Stage ◽  
Secondary Growth ◽  
Cytoplasmic Organelles ◽  
Transmission Electron ◽  
Candidate Species ◽  
Vitellogenic Stage ◽  
Epithelial Compartment ◽  
Vitelline Envelope ◽  
Structure And Ultrastructure

Abstract Introduction: Structure, ultrastructural features and degeneration of oogenesis were first investigated in female Rastrelliger brachysoma as new candidate species for aquaculture by transmission electron microscopy. Materials and Methods: Specimens were naturally collected during the breeding season from Samut Songkhram Province, Thailand. Results: The ultrastructure of female oogenesis was principally divided into five stages based on the nuclear characterization and cytoplasmic organelles; (i) oogonium; (ii) previtellogenic; (iii) lipid and cortical alveolar; (iv) early and (v) late vitellogenic stages. Initially, oogonium was present within cell nest in the epithelial compartment. Its cell was supported by prefollicular cells. The multiple nucleoli in previtellogenic stage, referring to primary growth stage were the first to appear and they were scattered around the peripheral of nuclear membrane with the increasing number of cytoplasmic organelles. Some microvilli of granulosa cell initially protruded into the vitelline envelope. A simple layer of flattened granulosa and theca cells was also observed. The lipid and cortical alveolar stage under secondary growth oocyte was accumulated with two inclusions; the lipid droplets and cortical alveoli in the ooplasm. Another characterization, the increasing of numerous microvilli was also detected in the vitelline envelope. Finally, in the vitellogenic stage, a massive uptake and processing of proteins into yolk platelets due to embedding of the numerous microvilli in the largest vitelline envelope was observed. Oocyte degeneration in R. brachysoma was novel found especially oogonial and previtellogenic stages. Conclusion: Five oogenic stages of this fish are found with the changing of the arrangement of nucleus, cytoplasmic organelles and follicular complex, which will be applied to further studies.

scholarly journals Subcellular Investigation of Photosynthesis-Driven Carbon Assimilation in the Symbiotic Reef Coral Pocillopora damicornis

mBio ◽  
2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Christophe Kopp ◽  
Isabelle Domart-Coulon ◽  
Stephane Escrig ◽  
Bruno M. Humbel ◽  
Michel Hignette ◽  
...  
Keyword(s):  
Lipid Droplets ◽  
Secondary Ion Mass Spectrometry ◽  
Reef Coral ◽  
Carbon Assimilation ◽  
Isotopic Labeling ◽  
Cellular Level ◽  
Coral Tissue ◽  
Pocillopora Damicornis ◽  
Carbon And Nitrogen ◽  
Transmission Electron

ABSTRACT  Reef-building corals form essential, mutualistic endosymbiotic associations with photosynthetic Symbiodinium dinoflagellates, providing their animal host partner with photosynthetically derived nutrients that allow the coral to thrive in oligotrophic waters. However, little is known about the dynamics of these nutritional interactions at the (sub)cellular level. Here, we visualize with submicrometer spatial resolution the carbon and nitrogen fluxes in the intact coral-dinoflagellate association from the reef coral Pocillopora damicornis by combining nanoscale secondary ion mass spectrometry (NanoSIMS) and transmission electron microscopy with pulse-chase isotopic labeling using [13C]bicarbonate and [15N]nitrate. This allows us to observe that (i) through light-driven photosynthesis, dinoflagellates rapidly assimilate inorganic bicarbonate and nitrate, temporarily storing carbon within lipid droplets and starch granules for remobilization in nighttime, along with carbon and nitrogen incorporation into other subcellular compartments for dinoflagellate growth and maintenance, (ii) carbon-containing photosynthates are translocated to all four coral tissue layers, where they accumulate after only 15 min in coral lipid droplets from the oral gastroderm and within 6 h in glycogen granules from the oral epiderm, and (iii) the translocation of nitrogen-containing photosynthates is delayed by 3 h. IMPORTANCE  Our results provide detailed in situ subcellular visualization of the fate of photosynthesis-derived carbon and nitrogen in the coral-dinoflagellate endosymbiosis. We directly demonstrate that lipid droplets and glycogen granules in the coral tissue are sinks for translocated carbon photosynthates by dinoflagellates and confirm their key role in the trophic interactions within the coral-dinoflagellate association.

scholarly journals Comparison of the effects of difenacoum and brodifacoum on the ultrastructure of rat liver cells

2016 ◽  
Vol 67 (3) ◽  
pp. 204-209 ◽  
Author(s):  
Nursel Gül ◽  
Nuri Yiğit ◽  
Fulya Saygılı ◽  
Ebru Demirel ◽  
Ceren Geniş
Keyword(s):  
Rat Liver ◽  
Lipid Droplets ◽  
Liver Cells ◽  
Mitochondrial Morphology ◽  
Cytotoxic Effects ◽  
Cytoplasmic Material ◽  
Transmission Electron ◽  
Biochemical Assays ◽  
Rat Liver Cells ◽  
Contrast Exposure

Abstract We used transmission electron microscopy to examine the cytotoxic effects of the second-generation anticoagulant rodenticides difenacoum and brodifacoum on rat liver. A single dose of difenacoum or brodifacoum was administered to rats by gastric gavage and liver samples were taken after 24 h, four days or seven days. In the livers of rats treated with difenacoum for 24 h, hepatocytes typically showed increased numbers of lysosomes, as well as enlargement of both the perinuclear space and the cisternae of the rough endoplasmic reticulum (RER), while sinusoids were irregularly shaped and contained Kupffer cells. Similar irregularities occurred in brodifacoum-treated rats at the same time point, but additionally increased numbers of vacuoles, damaged mitochondrial cristae, and clumping of chromatin were observed in hepatocytes, and hemolysed erythrocytes were noted in the sinusoids. Comparable findings were made in each group of rats after four days. After seven days of difenacoum treatment, hepatocytes suffered loss of cytoplasmic material and mitochondrial shrinkage, while RER cisternae became discontinuous. In contrast, exposure to brodifacoum for seven days caused the formation of numerous vacuoles and lipid droplets, disordered mitochondrial morphology, chromatin clumping and invagination of the nuclear envelope in hepatocytes. Sinusoids in the livers of rodenticide-treated rats contained an accumulation of dense material, lipid droplets, cells with pycnotic nuclei and hemolysed erythrocytes. Overall, our results show that brodifacoum causes more severe effects in liver cells than difenacoum. Thus our microscopic data along with additional biochemical assays point to a severe effect of rodenticide on vertebrates.

Observations of Domain Structure at Initial Growth Stage of PbTiO3 Thin Films Grown by Mocvd

1999 ◽  
Vol 596 ◽  
Author(s):  
H. Fujisawa ◽  
M. Shimizu ◽  
H. Niu ◽  
K. Honda ◽  
S Ohtani
Keyword(s):  
Thin Films ◽  
Domain Structure ◽  
Growth Stage ◽  
Domain Walls ◽  
Chemical Vapor ◽  
Initial Growth ◽  
Continuous Film ◽  
Cross Sectional ◽  
Initial Growth Stage ◽  
Transmission Electron

AbstractDomain structure and growth mechanism of PbTiO3 thin films were investigated using a transmission electron microscopy(TEM) from the viewpoint of size effects. At initial growth stage of (111)-oriented PbTiO3 films prepared by metalorganic chemical vapor deposition(MOCVD), triangle-shaped islands were grown on Pt(111)/SiO2/Si before becoming a continuous film. Triangular islands grew gradually in a lateral dimension. This means that PbTiO3 films grew two-dimensionally at initial growth stage. In cross-sectional TEM photomicrographs, (101)-twin boundaries (90° domain walls) and inclination of {110} or {101}-plane were observed in PbTiO3 islands. This result indicates that such small PbTiO3 islands have a tetragonal structure and could have spontaneous polarization. The minimum island which had 90° domain walls was 10nm high and 18nm wide.

Skeletal Muscle Ultrastructural Alterations In Alcoholism

1999 ◽  
Vol 5 (S2) ◽  
pp. 1162-1163
Author(s):  
B. Müller ◽  
H.J. Finol ◽  
I. Montes de Oca ◽  
A. Mayorca.
Keyword(s):  
Internal Medicine ◽  
Skeletal Muscle ◽  
Muscle Weakness ◽  
Lipid Droplets ◽  
Chronic Alcoholism ◽  
University Hospital ◽  
Proximal Muscle Weakness ◽  
Proximal Muscle ◽  
Alcoholic Myopathy ◽  
Transmission Electron

Two forms of muscular alterations have been described in alcoholic patients, one acute, the so called Hypokalemic alcoholic Myopathy; focal or diffuse pain, swelling, tenderness and weakness of skeletal muscle are the main clinical features, and the chronic one with proximal muscle weakness wich progresses slowly in a period of weeks or months Ultrastructurally myofibril disorganization and necrosis where described.In this work we present a systematic study of skeletal muscle alterations in four alcoholic patients who attended the Department of Internal Medicine at Caracas University Hospital . The patients were males, ages between 56 and 62 years old, and presented chronic alcoholism with muscle weakness with a more distal distribution and polymyalgia. Biopsies were taken from quadriceps femorismuscle with a percutaneous neddle and processed for routine transmission electron microscopy.Muscle fibers showed different degrees of atrophy with myofibril disorganization (Fig.l) and disappearence (Fig.2). Myonuclei were hyperchromatic and intermyofibrilar spaces were widened and exhibited abundant lipid droplets.

TRANSMISSION ELECTRON MICROSCOPY OF FUNGAL NEMATODE-TRAPPING DEVICES

1979 ◽  
Vol 59 (3) ◽  
pp. 785-795 ◽  
Author(s):  
S. S. TZEAN ◽  
R. H. ESTEY
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cytoplasmic Organelles ◽  
Dense Bodies ◽  
Transmission Electron ◽  
Luminal Side ◽  
Septal Pores ◽  
Trapping Devices

The nematode-trapping devices of Arthrobotrys dactyloides (constricting rings), Monacrosporium cionopagum (adhesive columnar processes and scalariform loops) and a Dactylella sp. (sticky knobs) were investigated by electron microscopy. The cells of the constricting rings prior to inflation contained normal cytoplasmic organelles and some unusual, oblong, electron-dense inclusions in the luminal side of the protoplast, and lomasomes associated with papillate cylindrical bodies in the peripheral side. Their luminal walls differed from their peripheral walls in structure and thickness. After inflation, the ring cells had thinner luminal walls, the electron-dense inclusions were absent, there were fewer lomasomes, the cells had larger vacuoles, some of which contained electron-dense fine granules, and Woronin bodies were plugging the septal pores. It is postulated that the cells of constricting rings are inflated by means of rapidly generated gases rather than by an inflow of fluids. The sticky knob, adhesive columnar process, and scalariform loop trapping devices exhibited numerous globose electron-dense bodies, especially in their peripheral protoplasts.

Structure and Ultrastructure of the Tracheary Elements of Asplenium (Pteridophyta) from the “Yungas”, Argentina

IAWA Journal ◽  
2010 ◽  
Vol 31 (2) ◽  
pp. 227-240 ◽  
Author(s):  
María Luján Luna ◽  
Gabriela Elena Giudice ◽  
María Alejandra Ganem ◽  
Elías Ramón de la Sota
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Maturation Stage ◽  
Tracheary Elements ◽  
Transmission Electron ◽  
Pit Membrane ◽  
Membrane Hydrolysis ◽  
Structure And Ultrastructure ◽  
Scanning Electron

The structure of root and rhizome tracheary cells of Asplenium spp. (Filicales, Pteridophyta) growing in NW Argentina was studied using light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In all cases, tracheary cells consisted of tracheids with various facets, mainly with scalariform pitting. With SEM, intertracheary pit membranes appeared smooth and non porose in most cases. In some instances, porose or web-like to thread-like pit membranes were noticed in rhizome tracheids. Under TEM secondary walls displayed a smooth and uniform appearance. Pit membranes showed a variation in thickness in presumed association with their maturation stage. More mature tracheary cells showed pit membranes with a mesh-like aspect and visible openings or pores. These characteristics are attributed to pit membrane hydrolysis, which facilitates water transport among tracheary cells.

Structure, function and secretory products of the peltate glands of Centrolobium tomentosum (Fabaceae, Faboideae)

2012 ◽  
Vol 60 (4) ◽  
pp. 301 ◽  
Author(s):  
Esmeire Cruz Matos ◽  
Élder Antônio Sousa Paiva
Keyword(s):  
Three Dimensional ◽  
Secretory Cells ◽  
Secretory Product ◽  
Vegetative Organs ◽  
Transmission Electron ◽  
Histochemical Tests ◽  
Glandular Structures ◽  
Secretory Products ◽  
Development Structure ◽  
Structure And Ultrastructure

The glandular structures of Centrolobium tomentosum Guill. ex Benth. have been little studied despite the economic importance of this species. We describe here the distribution, development, structure and ultrastructure of the secretory cells of the peltate glands found on the vegetative organs of this species. Stem apices and leaves in various stages of development were collected and prepared for examination by light, scanning and transmission electron microscopy. Chemical analyses and conventional histochemical tests to determine the chemical nature of the secretory products were also carried out. Peltate glands occur on aerial vegetative organs during their primary growth stage. These trichomes are structurally stable, persisting throughout the development of the organ. During the initial stages of the gland development, cell separation creates a central space that expands as secretions accumulate. Maximum secretion rates occur during this phase and the secreting cells characteristically have well developed smooth and rough endoplasmic reticulum, and high numbers of plastids and mitochondria. During the later stages of the secretory phase, the central cells show symptoms of cell death and are incorporated in to the secretions. At trichome maturity, the central space is delimited by a uniseriate epithelium. In addition to the resin, which is the main secretory product, an extensive three-dimensional carbohydrate matrix was observed that extended throughout the central space, apparently giving support to the resin droplets. The terpenic nature of the secretion was confirmed by thin-layer chromatography. Given the terpenic nature of the secretion and the permanence of trichomes throughout all phases of leaf development, it is postulated that the resin-secreting trichomes act to protect the plant against herbivores.

Nectary ultrastructure and secretory modes in three species of Tillandsia (Bromeliaceae) that have different pollinators

Botany ◽  
2013 ◽  
Vol 91 (11) ◽  
pp. 786-798 ◽  
Author(s):  
Stefano Mosti ◽  
Cynthia Ross Friedman ◽  
Ettore Pacini ◽  
Luigi Brighigna ◽  
Alessio Papini
Keyword(s):  
Electron Microscopy ◽  
Amino Acids ◽  
Lipid Droplets ◽  
Protein Crystals ◽  
Transmission Electron ◽  
Floral Nectaries ◽  
Secretion Product ◽  
Pollination Mode ◽  
Cell Wall Ingrowths ◽  
Holocrine Secretion

The floral nectaries of three Tillandsia L. spp. having different pollinators were investigated with transmission electron microscopy (TEM) to describe the previously unstudied ultrastructure of the nectar-producing tissues (primarily the epidermis) and also to determine if any differences in the ultrastructural features could be correlated to pollination mode. We determined that there were variations in nectaries among the three species, and that these may be linked to pollinator choice. Tillandsia seleriana Mez, which has a strict relationship with ants, had a nectary epithelium characterized by abundant dictyosomes and endoplasmic reticulum (ER), and a final degeneration stage possibly leading to holocrine secretion. The presence of protein crystals in epithelial plastids was correlated to a nectar enriched with amino acids and proteins, likely functioning to provide a protein-enriched diet and possibly defence against pathogens. Epithelial cells of the hummingbird-pollinated Tillandsia juncea (Ruiz et Pav.) Poir. nectary displayed cell wall ingrowths and dictyosomes and also contained cytoplasmic lipid droplets and protein crystals within plastids, both of which would enrich the nectar for hummingbirds. The nectary epithelium and the parenchyma of bat-pollinated Tillandsia grandis Schltdl. possessed a few cubic protein crystals in the plastids and its secretion product appeared electron transparent.

Effects of Preparation Approaches and Oxidizing agents on the Yield, Morphology and Thermal stability of Polyaniline

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Wan Ahmad Kamil Mahmood ◽  
Mohammad Mizanur Rahman Khan ◽  
Yeap Guan Yeow ◽  
Yee Keat Wee
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Reaction Time ◽  
Secondary Growth ◽  
Rapid Mixing ◽  
Oxidizing Agents ◽  
Mechanical Stirring ◽  
Transmission Electron ◽  
Ft Ir ◽  
Polymerization Method

Abstract Evidence of the control of yield and different morphological features of polyaniline (PANI), along with their higher thermal stability is reported. The syntheses were performed by varying the reaction time from 2 to 6 hours for three different methods using three different oxidizing agents. The freshly prepared PANI was investigated by means of fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-Vis), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The polymer yield was increased with the increasing of reaction time from 2 to 6 h for all oxidants in the synthesis approaches; while the reverse trend was observed for KPS in rapid mixing polymerization and mechanical stirring methods. The highest yield was obtained for 6 h reaction time using APS through mechanical stirring method. FESEM analysis showed the growth of regular and uniform PANI nanoparticles, along with the prevention of secondary growth and agglomeration of primary nanofibers using all three oxidizing agents for sonochemistry and rapid mixing polymerization method, except H2O2 in the case of later technique. However, irregular and agglomerated PANI was found for all oxidants in mechanical stirring method. TGA data showed that PANI synthesized by mechanical stirring method is thermally more stable than those prepared by sonochemistry and rapid mixing polymerization.

Light and transmission electron microscopy of English oak ectomycorrhizal short roots

1984 ◽  
Vol 62 (7) ◽  
pp. 1327-1335 ◽  
Author(s):  
H. H. Edwards ◽  
R. V. Gessner
Keyword(s):  
Electron Microscopy ◽  
Cell Walls ◽  
Quercus Robur ◽  
Lipid Droplets ◽  
Apical Meristem ◽  
Fungal Symbiont ◽  
Host Root ◽  
Transmission Electron ◽  
Cell Layers ◽  
English Oak

The incorporation of caffeine in standard transmission electron microscope fixation procedures has allowed good preservation and embedment of ectomycorrhizal short roots of English oak (Quercus robur L.). In the mantle the most conspicuous structures are cystidia which radiate outwards from the surface. These conically shaped cells have knobs at their tips and thickened cell walls. The cystidia and other outer mantle cells contain many cytoplasmic constituents, whereas the inner mantle cells are nearly devoid of cytoplasm. The mantle cells are held together by an intercellular slime network. The Hartig net cells are filled with cytoplasm and contain numerous lipid droplets. Typical dolipore septa separate the cells; however, these cells have irregularly branched shapes. The host root tissue appears little altered by the presence of the fungal symbiont. However, the root cap consists of only a few cell layers. The apical meristem is functional as evidenced by the presence of newly divided cells and microtubules lining enlarging cells.

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