scholarly journals Morphological changes in hepatocytes of rats deprived of dietary nucleotides

1996 ◽  
Vol 76 (4) ◽  
pp. 579-589 ◽  
Author(s):  
Ana T. Lopez-Navarro ◽  
Juan D. Bueno ◽  
Angel Gil ◽  
Antonio Sánchez-Pozo
Keyword(s):  
Morphological Changes ◽  
Chromatin Condensation ◽  
Negative Effects ◽  
Adult Rats ◽  
Transmission Electron ◽  
Dietary Nucleotides ◽  
Liver Morphology ◽  
Ultrastructure And Function ◽  
And Function ◽  
Ribosome Association

The aim of the present study was to investigate the influence of dietary nucleotides on liver morphology. Adult rats were fed for 21 d on a nucleotide-containing diet or the same diet free of nucleotides. Liver sections were examined by light and transmission electron microscopy, as well as for nucleic acid and protein contents. Morphometric analysis was performed for different variables. Deprivation of dietary nucleotides resulted in a reduction in hepatocyte nuclear and nucleolar areas as well as in nuclear chromatin condensation. In addition, the rough endoplasmic reticulum was reduced, as were ribosome association and abundance, whereas fat accumulated. These findings portray dietary nucleotides as required nutrients for the liver under normal physiological conditions and suggest that an inadequate supply of nucleotides for a certain period of time has transient negative effects on liver ultrastructure and function.

Comparative spermatology of 11 species of Polyplacophora (Mollusca) from the suborders Lepidopleurina, Chitonina and Acanthochitonina

1988 ◽  
Vol 235 (1279) ◽  
pp. 161-177 ◽  
Keyword(s):  
Electron Microscopy ◽  
Morphological Changes ◽  
Chromatin Condensation ◽  
Nuclear Material ◽  
Taxonomic Character ◽  
Anterior Portion ◽  
Preliminary Examination ◽  
Transmission Electron ◽  
Species Specific ◽  
Egg Coat

Transmission electron microscopy of the spermatozoa and spermatogenesis of 11 species (in three suborders Chitonina, Acanthochitonina, Lepidopleurina) of chiton has shown that each species has a sperm with a unique morphology indicating that spermatozoa can be used as a taxonomic character. Although structure is species-specific, similarities between species within suborders and subfamilies can be recognized. The spermatozoa of species from the suborders Chitonina and Acanthochitonina have a head comprising nuclear material only, the anterior portion of which is in the form of a long thin (approximately 80 nm diameter) filament. In many species the centrioles and mitochondria of the mid-piece are lateral in position, the mitochondria often being sited anteriorly alongside the nucleus. By contrast, Leptochiton asellus , a member of the more ancient suborder Lepidopleurina, has a sperm with a head comprising a nucleus and an acrosome. The mid-piece is also more conven­tional in structure with a ring of five or six spherical mitochondria (sited behind the nucleus) that surround the centrioles. The presence of the acrosome in L. asellus suggests that in the more recent chitons the acro­some has been secondarily lost. It is proposed that loss of the acrosome is correlated to a modification in egg-coat thickness. A preliminary examination of the structure of the eggs of three species has shown that those of L. asellus are surrounded by a very thick chorion (14-30 μm) whereas in Acanthochitona crinitus and Dinoplax gigas there are regions of the chorion that are less than 2 μm thick. The morphological changes that occur during spermatogenesis are very similar in the Chitonina and Acanthochitonina. During spermiogenesis the nucleus elongates to develop a long anterior filament. Chro­matin condensation within the nucleus involves the formation of fibrils that become orientated along its long axis. Closely associated with the elongating nucleus is a manchette. In L . asellus a spherical proacrosomal vesicle appears in the spermatocytes. This vesicle becomes compressed as it matures and simultaneously it migrates to the presumptive anterior end of the spermatid where it invaginates and elongates. Although the pattern of chromatin condensation in the nucleus is similar to that described above, a manchette has not been observed.

scholarly journals Mechanism of formation, ultrastructure, and function of the cytoplasmic bridge system during morphogenesis in Volvox.

1981 ◽  
Vol 91 (3) ◽  
pp. 756-769 ◽  
Author(s):  
K J Green ◽  
G I Viamontes ◽  
D L Kirk
Keyword(s):  
Mechanism Of Formation ◽  
Cell Interior ◽  
Cytoplasmic Bridge ◽  
Transmission Electron ◽  
Actual Movement ◽  
Ultrastructure And Function ◽  
And Function ◽  
And Inversion ◽  
Isolated Cell ◽  
Bridge System

The cytoplasmic bridge system that links all cells of a Volvox embryo and plays a crucial role in morphogenesis is shown to form as a result of localized incomplete cytokinesis; sometimes bridge formation occurs before other regions of the cell have begun to divide. Vesicles, believed to be derived from the cell interior, align along the presumptive cleavage furrow in the bridge-forming region. Apparently it is where these vesicles fail to fuse that bridges are formed. Conventional and high voltage transmission electron microscopy analyses confirm that bridges are regularly spaced; they possess a constant, highly ordered structure throughout cleavage and inversion. Concentric cortical striations (similar to those observed previously in related species) ring each bridge throughout its length and continue out under the plasmalemma of the cell body to abut the striations of neighboring bridges. These striations are closely associated with an electron-dense material that coats the inner face of the membrane throughout the bridge region and appears to be thickest near the equator of each bridge. In addition to the parallel longitudinal arrays of cortical microtubules that traverse the cells, we observed microtubules that angle into and through the bridges during cleavage; however, the latter are not seen once inversion movements have begun. During inversion, bridge bands undergo relocation relative to the cell bodies without any loss of integrity or change in bridge spacing. Observation of isolated cell clusters reveals that it is the sequential movement of individual cells with respect to a stationary bridge system, and not actual movement of the bridges, that gives rise to the observed relocation.

scholarly journals Antiproliferative, Ultrastructural, and Physiological Effects of Amiodarone on Promastigote and Amastigote Forms of Leishmania amazonensis

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Sara Teixeira de Macedo-Silva ◽  
Thais Larissa Araújo de Oliveira Silva ◽  
Julio A. Urbina ◽  
Wanderley de Souza ◽  
Juliany Cola Fernandes Rodrigues
Keyword(s):  
Specific Activity ◽  
Close Association ◽  
Chromatin Condensation ◽  
Membrane Integrity ◽  
Symptomatic Treatment ◽  
Leishmania Amazonensis ◽  
Dependent Manner ◽  
Intracellular Amastigotes ◽  
Transmission Electron ◽  
And Function

Amiodarone (AMIO), the most frequently antiarrhythmic drug used for the symptomatic treatment of chronic Chagas' disease patients with cardiac compromise, has recently been shown to have also specific activity against fungi, Trypanosoma cruzi and Leishmania. In this work, we characterized the effects of AMIO on proliferation, mitochondrial physiology, and ultrastructure of Leishmania amazonensis promastigotes and intracellular amastigotes. The IC50 values were 4.21 and 0.46 μM against promastigotes and intracellular amastigotes, respectively, indicating high selectivity for the clinically relevant stage. We also found that treatment with AMIO leads to a collapse of the mitochondrial membrane potential (ΔΨm) and to an increase in the production of reactive oxygen species, in a dose-dependent manner. Fluorescence microscopy of cells labeled with JC-1, a marker for mitochondrial energization, and transmission electron microscopy confirmed severe alterations of the mitochondrion, including intense swelling and modification of its membranes. Other ultrastructural alterations included (1) presence of numerous lipid-storage bodies, (2) presence of large autophagosomes containing part of the cytoplasm and membrane profiles, sometimes in close association with the mitochondrion and endoplasmic reticulum, and (3) alterations in the chromatin condensation and plasma membrane integrity. Taken together, our results indicate that AMIO is a potent inhibitor of L. amazonensis growth, acting through irreversible alterations in the mitochondrial structure and function, which lead to cell death by necrosis, apoptosis and/or autophagy.

scholarly journals Linking Ultrastructure and Function in Four Genera of Anaerobic Ammonium-Oxidizing Bacteria: Cell Plan, Glycogen Storage, and Localization of Cytochrome c Proteins

2007 ◽  
Vol 190 (2) ◽  
pp. 708-717 ◽  
Author(s):  
Laura van Niftrik ◽  
Willie J. C. Geerts ◽  
Elly G. van Donselaar ◽  
Bruno M. Humbel ◽  
Richard I. Webb ◽  
...  
Keyword(s):  
Electron Tomography ◽  
Glycogen Storage ◽  
Anammox Bacteria ◽  
Ammonium Oxidation ◽  
Intracytoplasmic Membrane ◽  
Transmission Electron ◽  
Cell Plan ◽  
Ultrastructure And Function ◽  
And Function ◽  
Common Cell

ABSTRACT Anaerobic ammonium oxidation (anammox) is an ecologically and industrially important process and is performed by a clade of deeply branching Planctomycetes. Anammox bacteria possess an intracytoplasmic membrane-bounded organelle, the anammoxosome. In the present study, the ultrastructures of four different genera of anammox bacteria were compared with transmission electron microscopy and electron tomography. The four anammox genera shared a common cell plan and contained glycogen granules. Differences between the four genera included cell size (from 800 to 1,100 nm in diameter), presence or absence of cytoplasmic particles, and presence or absence of pilus-like appendages. Furthermore, cytochrome c proteins were detected exclusively inside the anammoxosome. This detection provides further support for the hypothesis that this organelle is the locus of anammox catabolism.

scholarly journals Susceptibility of mouse primary cortical neuronal cells to coxsackievirus B

2004 ◽  
Vol 85 (6) ◽  
pp. 1555-1564 ◽  
Author(s):  
Jeonghyun Ahn ◽  
Jene Choi ◽  
Chul Hyun Joo ◽  
Ilseon Seo ◽  
DongHou Kim ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Chromatin Condensation ◽  
Neuronal Cells ◽  
Virus Production ◽  
Cytopathic Effects ◽  
Transmission Electron ◽  
Coxsackievirus B ◽  
Transcription Inhibitor ◽  
Nuclear Changes ◽  
Induced Apoptosis

Coxsackievirus B (CVB) is often associated with aseptic meningitis and encephalitis, but the six serotypes of CVB vary in their relative disease severity. To elucidate the detailed mechanisms of CVB-induced cytopathological effects, the morphological and biochemical characteristics caused by the CVB serotypes in mouse primary cortical neuronal cells were investigated. By 24 h post-infection, all CVB serotypes except CVB2 induced severe cytotoxic alterations, including a loss of neurites. Both fluorescence and transmission electron microscopy revealed CVB-induced morphological changes indicative of apoptosis, including heavily condensed nuclei, subsequent chromatin condensation into the periphery of the nuclei and oligonucleosomal DNA fragmentation. It was also found that infection with all six CVB serotypes led to productive virus replication, which was completed prior to an apoptotic signal. The caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone significantly inhibited nuclear changes associated with virus-induced apoptosis, but had less effect on virus-associated cytopathic effects and no effect on virus production. In contrast, the transcription inhibitor actinomycin D profoundly inhibited all three virus-induced events. Taken together, these findings demonstrate that all six CVB serotypes can efficiently replicate in mouse cortical neuronal cells and that productive replication of these CVBs, except for CVB2, induces multiple cytopathological effects, including apoptotic alterations.

Ultrastructural Changes in the Venous Wall Induced by Experimental Diabetes: Preliminary Findings

1995 ◽  
Vol 10 (2) ◽  
pp. 69-74 ◽  
Author(s):  
B. Mompeó ◽  
F. Ortega ◽  
L. Sarmiento
Keyword(s):  
Experimental Diabetes ◽  
Morphological Changes ◽  
Femoral Vein ◽  
Ultrastructural Changes ◽  
Adult Rats ◽  
Structural Alterations ◽  
Transmission Electron ◽  
Adventitial Cells ◽  
A Prospective Study ◽  
Venous Wall

Objective: To study whether experimental streptozotocin (STZ) induced diabetes results in structural alterations to the venous wall of the femoral vein in adult rats, in order to develop further studies using this model. Design: A prospective study of femoral veins obtained from controls and STZ-induced diabetes rats. Setting: Department of Morphology, Universidad de Las Palmas de Gran Canaria, Spain. Interventions: Experimental diabetes induced by intraperitoneal injection of streptozotocin. Main outcome measures: The samples were studied at 6 and 12 weeks post-injection using light and transmission electron microscopy. Results: The results show that the venous wall is affected by an increase in the deposition of extracellular tissue. In addition the endothelial, muscular and adventitial cells show morphological changes. Conclusions: Our results demonstrate significant alterations in the venous wall due to hyperglycaemia in the STZ-animal model.

Ultrastructural Study of Rat Colon Following Psyllium Ingestion

1985 ◽  
Vol 43 ◽  
pp. 580-581
Author(s):  
F.G. Lightfoot ◽  
L.E. Grau ◽  
M.M. Cassidy ◽  
G.R. Tadvalkar ◽  
G.V. Vahouny
Keyword(s):  
Electron Microscopy ◽  
Morphological Changes ◽  
Large Population ◽  
Rat Colon ◽  
Gastrointestinal Disorders ◽  
Luminal Surface ◽  
Fecal Material ◽  
Transmission Electron ◽  
Morphologic Analysis ◽  
Irritable Bowel

Psyllium hydrophillic mucilloid is a natural gelling fiber consumed by a large population of our society. It is used as a bulk-producing laxative and in the treatment of gastrointestinal disorders such as “Irritable Bowel Syndrome”. The literature pertaining to the ultrastructural effects of this agent is sparse.This study documents morphological changes induced by psyllium. Animals fed a diet containing 2% psyllium for four weeks were subsequently sacrificed and processed for scanning and transmission electron microscopy. The colon contained fecal material combined with psyllium which conformed to the contour of the luminal surface. This mixture formed surface replicas of the intestinal mucosa. These replicas and their related colonic sites were processed for morphologic analysis.

Correlation Between Cellular Functions and Morphological Changes of Human Trophoblast in Vitro

1975 ◽  
Vol 33 ◽  
pp. 600-601
Author(s):  
John C. Garancis ◽  
Robert O. Hussa ◽  
Michael T. Story ◽  
Donald Yorde ◽  
Roland A. Pattillo
Keyword(s):  
Electron Microscopy ◽  
Cellular Proliferation ◽  
Morphological Changes ◽  
Culture Fluid ◽  
Cellular Functions ◽  
Human Trophoblast ◽  
Transmission Electron ◽  
Marked Activity ◽  
Malignant Trophoblast

Human malignant trophoblast cells in continuous culture were incubated for 3 days in medium containing 1 mM N6-O2'-dibutyryl cyclic adenosine 3':5'-monophosphate (dibutyryl cyclic AMP) and 1 mM theophylline. The culture fluid was replenished daily. Stimulated cultures secreted many times more chorionic gonadotropin and estrogens than did control cultures in the absence of increased cellular proliferation. Scanning electron microscopy revealed remarkable surface changes of stimulated cells. Control cells (not stimulated) were smooth or provided with varying numbers of microvilli (Fig. 1). The latter, usually, were short and thin. The surface features of stimulated cells were considerably different. There was marked increase of microvilli which appeared elongated and thick. Many cells were covered with confluent polypoid projections (Fig. 2). Transmission electron microscopy demonstrated marked activity of cytoplasmic organelles. Mitochondria were increased in number and size; some giant forms with numerous cristae were observed.

Structure of contact sites between the outer and inner mitochondrial membranes investigated by HVEM tomography

1996 ◽  
Vol 54 ◽  
pp. 966-967
Author(s):  
C.A. Mannella ◽  
K.F. Buttle ◽  
K.A. O‘Farrell ◽  
A. Leith ◽  
M. Marko
Keyword(s):  
Liver Mitochondrion ◽  
Adenine Nucleotide ◽  
Protein Complexes ◽  
Mitochondrial Membranes ◽  
Electron Microscopic ◽  
Contact Sites ◽  
Transmission Electron ◽  
Precursor Proteins ◽  
Membrane Contacts ◽  
And Function

Early transmission electron microscopy of plastic-embedded, thin-sectioned mitochondria indicated that there are numerous junctions between the outer and inner membranes of this organelle. More recent studies have suggested that the mitochondrial membrane contacts may be the site of protein complexes engaged in specialized functions, e.g., import of mitochondrial precursor proteins, adenine nucleotide channeling, and even intermembrane signalling. It has been suggested that the intermembrane contacts may be sites of membrane fusion involving non-bilayer lipid domains in the two membranes. However, despite growing interest in the nature and function of intramitochondrial contact sites, little is known about their structure.We are using electron microscopic tomography with the Albany HVEM to determine the internal organization of mitochondria. We have reconstructed a 0.6-μm section through an isolated, plasticembedded rat-liver mitochondrion by combining 123 projections collected by tilting (+/- 70°) around two perpendicular tilt axes. The resulting 3-D image has confirmed the basic inner-membrane organization inferred from lower-resolution reconstructions obtained from single-axis tomography.

The Impact of L-Carnitine and Coenzyme Q10 as Protection Against Busulfan-Oxidative Stress in the Liver of Adult Rats

2020 ◽  
Vol 10 (5) ◽  
pp. 578-586
Author(s):  
Areeg M. Abdelrazek ◽  
Shimaa A. Haredy
Keyword(s):  
Oxidative Stress ◽  
Coenzyme Q10 ◽  
Protective Role ◽  
Albino Rats ◽  
Distilled Water ◽  
Negative Effects ◽  
Adult Rats ◽  
Stress Damage ◽  
The Impact ◽  
Liver Tissues

Background: Busulfan (Bu) is an anticancer drug with a variety of adverse effects for cancer patients. Oxidative stress has been considered as a common pathological mechanism and it has a key role in the initiation and progression of liver injury by Bu. Aim: The study aimed to evaluate the antioxidant impact of L-Carnitine and Coenzyme Q10 and their protective role against oxidative stress damage in liver tissues. Methods and Material: Thirty-six albino rats were divided equally into six groups. G1 (con), received I.P. injection of DMSO plus 1 ml of distilled water daily by oral gavages; G2 (Bu), received I.P. injection of Bu plus 1 ml of the distilled water daily; G3 (L-Car), received 1 ml of L-Car orally; G4 (Bu + L-Car) received I.P. injection of Bu plus 1 ml of L-Car, G5 (CoQ10) 1 ml of CoQ10 daily; and G6 (Bu + CoQ10) received I.P. injection of Bu plus 1 ml of CoQ10 daily. Results: The recent data showed that Bu induced significant (P<0.05) elevation in serum ALT, AST, liver GSSG, NO, MDA and 8-OHDG, while showing significant (P<0.05) decrease in liver GSH and ATP. On the other hand, L-Carnitine and Coenzyme Q10 ameliorated the negative effects prompted by Bu. Immunohistochemical expression of caspase-3 in liver tissues reported pathological alterations in Bu group while also showed significant recovery in L-Car more than CoQ10. Conclusion: L-Car, as well as CoQ10, can enhance the hepatotoxic effects of Bu by promoting energy production in oxidative phosphorylation process and by scavenging the free radicals.

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