scholarly journals Compartmentalization in Penicillin G Biosynthesis by Penicillium chrysogenum PQ-96

2014 ◽  
Vol 63 (4) ◽  
pp. 399-408 ◽  
Author(s):  
WIESŁAW KURZĄTKOWSKI ◽  
MONIKA STANISZEWSKA ◽  
MAŁGORZATA BONDARYK ◽  
ANITA GĘBSKA-KUCZEROWSKA
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
High Activity ◽  
Penicillium Chrysogenum ◽  
Phenylacetic Acid ◽  
Penicillin G ◽  
Transmission Electron ◽  
Isopenicillin N ◽  
Peripheral Cytoplasm

The arrangement of organelles in the sub-apical productive non-growing vacuolated hyphal cells of the high- and the low-penicillin-pro- ducing strains Penicillium chrysogenum was compared using transmission electron microscopy. In the productive cells of the high-yielding strain the endoplasmic reticulum and the polyribosomes with associated peroxisomes are frequently arranged at the periphery of the cytoplasm and around the vacuoles. At the high activity of penicillin G biosynthesis the immuno-label of the cytosolic isopenicillin N synthase is concentrated at the polyribosomes arranged in the peripheral cytoplasm and along the tonoplast as well as around the peroxisomes. On the basis of the obtained results the compartmentalization of the pathway of penicillin G biosymthesis is discussed. The obtained results support the phenylacetic acid detoxification hypothesis of penicillin G biosynthesis.

scholarly journals Pollen, Tapetum, and Orbicule Development inColletia paradoxaandDiscaria americana(Rhamnaceae)

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
M. Gotelli ◽  
B. Galati ◽  
D. Medan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Ultrastructural Changes ◽  
Transmission Electron ◽  
The Family ◽  
Tapetal Cells ◽  
Grain Formation

Tapetum, orbicule, and pollen grain ontogeny inColletia paradoxaandDiscaria americanawere studied with transmission electron microscopy (TEM). The ultrastructural changes observed during the different stages of development in the tapetal cells and related to orbicule and pollen grain formation are described. The proorbicules have the appearance of lipid globule, and their formation is related to the endoplasmic reticulum of rough type (ERr). This is the first report on the presence of orbicules in the family Rhamnaceae. Pollen grains are shed at the bicellular stage.

scholarly journals Enigmatic origin of the poxvirus membrane from the endoplasmic reticulum shown by 3D imaging of vaccinia virus assembly mutants

2017 ◽  
Vol 114 (51) ◽  
pp. E11001-E11009 ◽  
Author(s):  
Andrea S. Weisberg ◽  
Liliana Maruri-Avidal ◽  
Himani Bisht ◽  
Bryan T. Hansen ◽  
Cindi L. Schwartz ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Vaccinia Virus ◽  
Virus Assembly ◽  
Transmembrane Protein ◽  
Membrane Dynamics ◽  
Deletion Mutants ◽  
Viral Membrane ◽  
Transmission Electron

The long-standing inability to visualize connections between poxvirus membranes and cellular organelles has led to uncertainty regarding the origin of the viral membrane. Indeed, there has been speculation that viral membranes form de novo in cytoplasmic factories. Another possibility, that the connections are too short-lived to be captured by microscopy during a normal infection, motivated us to identify and characterize virus mutants that are arrested in assembly. Five conserved vaccinia virus proteins, referred to as Viral Membrane Assembly Proteins (VMAPs), that are necessary for formation of immature virions were found. Transmission electron microscopy studies of two VMAP deletion mutants had suggested retention of connections between viral membranes and the endoplasmic reticulum (ER). We now analyzed cells infected with each of the five VMAP deletion mutants by electron tomography, which is necessary to validate membrane continuity, in addition to conventional transmission electron microscopy. In all cases, connections between the ER and viral membranes were demonstrated by 3D reconstructions, supporting a role for the VMAPs in creating and/or stabilizing membrane scissions. Furthermore, coexpression of the viral reticulon-like transmembrane protein A17 and the capsid-like scaffold protein D13 was sufficient to form similar ER-associated viral structures in the absence of other major virion proteins. Determination of the mechanism of ER disruption during a normal VACV infection and the likely participation of both viral and cell proteins in this process may provide important insights into membrane dynamics.

scholarly journals Effects of ubiquitin C-terminal hydrolase L1 deficiency on mouse ova

Reproduction ◽  
2012 ◽  
Vol 143 (3) ◽  
pp. 271-279 ◽  
Author(s):  
Sayaka Koyanagi ◽  
Hiroko Hamasaki ◽  
Satoshi Sekiguchi ◽  
Kenshiro Hara ◽  
Yoshiyuki Ishii ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Proteomic Analysis ◽  
Ubiquitin Proteasome System ◽  
Underlying Mechanism ◽  
Wild Type ◽  
Transmission Electron ◽  
Ubiquitin Proteasome

Maternal proteins are rapidly degraded by the ubiquitin–proteasome system during oocyte maturation in mice. Ubiquitin C-terminal hydrolase L1 (UCHL1) is highly and specifically expressed in mouse ova and is involved in the polyspermy block. However, the role of UCHL1 in the underlying mechanism of polyspermy block is poorly understood. To address this issue, we performed a comprehensive proteomic analysis to identify maternal proteins that were relevant to the role of UCHL1 in mouse ova using UCHL1-deficientgad. Furthermore, we assessed morphological features ingadmouse ova using transmission electron microscopy. NACHT, LRR, and PYD domain-containing (NALP) family proteins and endoplasmic reticulum (ER) chaperones were identified by proteomic analysis. We also found that the ‘maternal antigen that embryos require’ (NLRP5 (MATER)) protein level increased significantly ingadmouse ova compared with that in wild-type mice. In an ultrastructural study,gadmouse ova contained less ER in the cortex than in wild-type mice. These results provide new insights into the role of UCHL1 in the mechanism of polyspermy block in mouse ova.

Interrelations between the Parasitophorous Vacuole ofToxoplasma gondiiand Host Cell Organelles

2005 ◽  
Vol 11 (2) ◽  
pp. 166-174 ◽  
Author(s):  
Rodrigo Cardoso Magno ◽  
Lorian Cobra Straker ◽  
Wanderley de Souza ◽  
Marcia Attias
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Host Cell ◽  
Fluorescent Probes ◽  
Parasitophorous Vacuole ◽  
Laser Scanning Microscopy ◽  
Cell Organelles ◽  
Apical Side ◽  
Transmission Electron

Toxoplasma gondii, the causative agent of toxoplasmosis, is capable of actively penetrating and multiplying in any nucleated cell of warm-blooded animals. Its survival strategies include escape from fusion of the parasitophorous vacuole with host cell lysosomes and rearrangement of host cell organelles in relation to the parasitophorous vacuole. In this article we report the rearrangement of host cell organelles and elements of the cytoskeleton of LLCMK2 cells, a lineage derived from green monkey kidney epithelial cells, in response to infection byT. gondiitachyzoites. Transmission electron microscopy made on flat embedded monolayers cut horizontally to the apical side of the cells or field emission scanning electron microscopy of monolayers scraped with scotch tape before sputtering showed that association of mitochondria to the vacuole is much less frequent than previously described. On the other hand, all parasitophorous vacuoles were surrounded by elements of the endoplasmic reticulum. These data were complemented by observations by laser scanning microscopy using fluorescent probes from mitochondria and endoplasmic reticulum and reinforced by three-dimensional reconstruction from serial sections observed by transmission electron microscopy and labeling of mitochondria and endoplasmic reticulum by fluorescent probes.

Ultrastructural Morphology of the Plastids in Ferocactus Latispinus (Haworth)

1981 ◽  
Vol 39 ◽  
pp. 648-649
Author(s):  
E. R. Rivera
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Apical Meristem ◽  
Plant Cells ◽  
Cortical Cells ◽  
Conventional Transmission Electron Microscopy ◽  
Meristematic Cells ◽  
Dense Cytoplasm ◽  
Transmission Electron ◽  
Peripheral Cytoplasm

Mature plants of Ferocactus latispinus were divided into the apical meristem, cortical and cambial tissue, and young and mature photosynthetic tissue. Pieces 2x2x4 mm were fixed in 0.075 M PIPES buffered 5% glutaraldehyde and further treated for conventional transmission electron microscopy.The shoot meristematic cells contained dense cytoplasm with a few small vacuoles. All organelles expected to be found in unspecialized plant cells were present. The proplastids were 1-2 diameters larger than mitochondria. Some of these plastids were elongated and most contained small amounts of lipid globules in the stroma (Fig. 1). In addition, phytoferritin was sometimes found in the stroma. No starch was found in these organelles. The thylakoids were poorly developed, and when there were no inclusions in the stroma, proplastids were difficult to distinguish from mitochondria (Fig. 1).Cortical cells had very large, well-developed vacuoles. The organelles were restricted to the peripheral cytoplasm of the cell and to a few transvacuolar cytoplasmic strands.

Studies on the ontogeny and ultrastructure of the sclerotium of Botrytis cinerea Pers. ex Nocca & Balbis

1982 ◽  
Vol 28 (12) ◽  
pp. 1347-1354 ◽  
Author(s):  
H. J. Willetts ◽  
Suzanne Bullock
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Botrytis Cinerea ◽  
Transmission Electron ◽  
Polyphosphate Bodies ◽  
Vacuolated Cells

The ontogeny and ultrastructure of sclerotia of the fungus Botrytis cinerea Pers. ex Nocca & Balbis were studied by light, scanning, and transmission electron microscopy. Exudation droplets of various sizes and colour accumulated on sclerotial surfaces during development and eventually disappeared. A surface hyphal weft was present over sclerotia at maturity, forming a dense covering which often obscured the underlying rind. The rind consisted of highly vacuolated cells with thick, pigmented walls that remained intact even in old sclerotia. The cortex was poorly defined and usually consisted of only one layer of cells. The prosenchymatous medulla constituted the main volume of mature sclerotia. The ultrastructure of young sclerotial hyphae was similar to that of actively growing vegetative hyphae. Hyphae of mature sclerotia contained fewer nuclei and profiles of mitochondria and endoplasmic reticulum than young sclerotial hyphae. Electron-dense structures, tentatively identified as protein and polyphosphate bodies, were observed in hyphae of the cortex and medulla. Sclerotia of B. cinerea were structurally similar to those of Sclerotinia spp.

Effect of Endoplasmic Reticulum Stress on Resveratrol-Induced Cardioprotection

2014 ◽  
Vol 651-653 ◽  
pp. 227-230
Author(s):  
Hammayun Ayub ◽  
Shakir Ahmed ◽  
Ayesha Yasin ◽  
Yi Dong Zhang ◽  
Zhuo Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Endoplasmic Reticulum Stress ◽  
Western Blotting ◽  
Mitochondrial Permeability Transition ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Mptp Opening ◽  
Transmission Electron

To investigate if resveratrol prevent the mitochondrial permeability transition pore (mPTP) opening through inhibition of endoplasmic reticulum stress (ERS). Methods: Rat heart tissue-derived cardiac H9c2 myoblast cell line was cultured. Fluorescence images of mitochondrial membrane potential were obtained with confocal microscopy. Western blotting analyzes the ERS marker protein GRP78 expression. Transmission electron microscopy detects the subcellular structure. Results: Exposure of cardiac H9c2 cells to 100 μM 2-DG, the ERS inducer, for 20 min caused a marked decrease in mitochondrial specific tetramethylrhodamine ethyl ester (TMRE) fluorescence. Resveratrol significantly prevented the loss of TMRE fluorescence. Western blotting revealed that resveratrol decreased GRP78 expression. Experiments with transmission electron microscopy revealed that resveratrol prevented 2-DG-induced swelling of endoplasmic reticulum and mitochondrial damages. Conclusions: These data suggest that inhibition of ERS leads to the prevention of mPTP opening. Resveratrol prevents the mPTP opening through inhibition of ERS.

The role of endoplasmic reticulum during gametogenesis in the aquatic fungus Allomyces macrogynus

1991 ◽  
Vol 69 (2) ◽  
pp. 336-341 ◽  
Author(s):  
Tommy C. Sewall ◽  
Jeffrey C. Pommerville
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Osmium Tetroxide ◽  
Cleavage Furrow ◽  
Aquatic Fungus ◽  
Transmission Electron ◽  
Allomyces Macrogynus ◽  
Zinc Iodide

The Chytridiomycete Allomyces macrogynus generates new membranes for cleavage furrow and nuclear-cap formation during gametogenesis and zoosporogenesis. Transmission electron microscopy after impregnation with a mixture of zinc iodide and osmium tetroxide clearly demonstrated changes in the endoplasmic reticulum. Endoplasmic reticulum was intensely stained but did not appear to contribute to the formation of the unstained flagellar membranes or cleavage furrows. However, the relative cytoplasmic volume of endoplasmic reticulum decreased as positively stained nuclear-cap membrane formed. These observations are consistent with the hypothesis that flagellar membranes and cleavage furrows are derived from trans-Golgi equivalents, whereas the nuclear-cap membrane is derived from the endoplasmic reticulum. Key words: Allomyces macrogynus, Chytridiomycetes, endoplasmic reticulum, gametogenesis, zoosporogenesis.

Electron microscopic study of oospore maturation and germination in an emasculate isolate of Saprolegnia ferax. 1. Gross changes

1980 ◽  
Vol 58 (2) ◽  
pp. 182-194 ◽  
Author(s):  
Gordon W. Beakes
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Microscopic Study ◽  
Electron Microscopic ◽  
Saprolegnia Ferax ◽  
Transmission Electron ◽  
Cytological Changes ◽  
Thin Walled ◽  
Germ Tubes ◽  
Peripheral Cytoplasm

The main morphological and cytological changes which accompany oospore maturation and germination in an emasculate isolate of Saprolegnia ferax have been followed by light and transmission electron microscopy. Oospore development proved similar to that described in antheridiate species except for the absence of motile granules within the central ooplast vacuole. Germination followed within a few days of maturation although it did not occur synchronously within a single oogonium. The ending of dormancy is indicated by a thinning of the oospore wall and a decrease in cytoplasmic refractivity. A new germination wall is secreted around the protoplast and the contents of the central ooplast break down and are partially dispersed into the peripheral cytoplasm as it becomes transformed into a typical somatic vacuole. Oospores swell slightly before the emergence of between one and four germ tubes. These often grow extensively within the oogonium, occasionally infesting and possibly parasitizing neighbouring germlings, before rupturing either the thin-walled pits or basal septa. After emergence most germ tubes continue to grow vegetatively in a sparsely branched fashion, although a few develop terminal sporangia. Oospore germination in this isolate is compared with that described in other oomycete species.

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