scholarly journals Coupling membranes as energy-transmitting cables. I. Filamentous mitochondria in fibroblasts and mitochondrial clusters in cardiomyocytes.

1988 ◽  
Vol 107 (2) ◽  
pp. 481-495 ◽  
Author(s):  
A A Amchenkova ◽  
L E Bakeeva ◽  
Y S Chentsov ◽  
V P Skulachev ◽  
D B Zorov
Keyword(s):  
Fluorescence Quenching ◽  
Human Fibroblasts ◽  
Condensed State ◽  
Rat Cardiomyocytes ◽  
Laser Illumination ◽  
Cluster Organization ◽  
A Cell ◽  
Mitochondrial Junctions ◽  
Branched Chains

An hypothesis considering mitochondria as intracellular power-transmitting protonic cables was tested in human fibroblasts where mitochondria are thin and long and in rat cardiomyocytes where they show cluster organization. Mitochondria in the cell were specifically stained with fluorescent-penetrating cation ethylrhodamine, which electrophoretically accumulates in the mitochondrial matrix. A 40-micron-long mitochondrial filament of fibroblast was illuminated by a very narrow (less than or equal to 0.5 micron) laser beam to induce local damage of the mitochondrial membranes. Such a treatment was found to induce quenching of the ethylrhodamine fluorescence in the entire filament. According to the electron microscope examination, the laser-treated filament retained its continuity after the laser illumination. Other mitochondrial filaments (some of which were localized at a distance less than 10 micron from the laser-treated one) remained fluorescent. In a cell where mitochondrial filaments seemed to be united in a network, laser illumination of one filament resulted in fluorescence quenching in the whole network, whereas fluorescence of small mitochondria not connected with the network was unaffected. The illumination of cardiomyocyte was found to result in the fluorescence quenching not only in a laser-illuminated mitochondrion but also in a large cluster of organelles composed of many mitochondria. Electron microscopy showed that all the mitochondria in the cluster change from the orthodox to the condensed state. It was also found that mitochondria in the cluster are connected to one another with specific junctions. If a mitochondrion did not form junctions with a quenched cluster, its fluorescence was not decreased even when this mitochondrion was localized close to an illuminated one. The size of the mitochondrial cluster may be as long as 50 micron. The cluster is formed by branched chains of contacting mitochondria, which may be defined as Streptio mitochondriale. In the cardiomyocyte there are several mitochondrial clusters or, alternatively, the quenched cluster is a result of decomposition of a supercluster uniting all the mitochondria of the cell. Cluster organization of mitochondria could also be revealed when a single mitochondrion was punctured in situ with a microcapillary. The obtained data are in agreement with the idea that mitochondrial junctions are H+ permeable so that, within the cluster, delta psi may be transmitted from one mitochondrion to another. The above results are consistent with the assumption that mitochondrial filaments or networks represent a united electrical system.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Intracellular distribution of histone mRNAs in human fibroblasts studied by in situ hybridization.

1988 ◽  
Vol 85 (2) ◽  
pp. 463-467 ◽  
Author(s):  
J. B. Lawrence ◽  
R. H. Singer ◽  
C. A. Villnave ◽  
J. L. Stein ◽  
G. S. Stein
Keyword(s):  
In Situ Hybridization ◽  
Human Fibroblasts ◽  
Intracellular Distribution ◽  
Histone Mrnas

scholarly journals An in situ near-ambient pressure X-ray Photoelectron Spectroscopy study of Mn polarised anodically in a cell with solid oxide electrolyte

2015 ◽  
Vol 174 ◽  
pp. 532-541 ◽  
Author(s):  
Benedetto Bozzini ◽  
Matteo Amati ◽  
Patrizia Bocchetta ◽  
Simone Dal Zilio ◽  
Axel Knop-Gericke ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Ambient Pressure ◽  
Solid Oxide ◽  
Spectroscopy Study ◽  
Solid Oxide Electrolyte ◽  
X Ray ◽  
A Cell ◽  
Oxide Electrolyte

scholarly journals Order and stochasticity in the folding of individual Drosophila genomes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sergey V. Ulianov ◽  
Vlada V. Zakharova ◽  
Aleksandra A. Galitsyna ◽  
Pavel I. Kos ◽  
Kirill E. Polovnikov ◽  
...  
Keyword(s):  
Random Walk ◽  
High Resolution ◽  
3D Genome ◽  
Topologically Associating Domains ◽  
Chromatin Folding ◽  
A Cell ◽  
Single Nucleus ◽  
High Level ◽  
Cell To Cell Variability

AbstractMammalian and Drosophila genomes are partitioned into topologically associating domains (TADs). Although this partitioning has been reported to be functionally relevant, it is unclear whether TADs represent true physical units located at the same genomic positions in each cell nucleus or emerge as an average of numerous alternative chromatin folding patterns in a cell population. Here, we use a single-nucleus Hi-C technique to construct high-resolution Hi-C maps in individual Drosophila genomes. These maps demonstrate chromatin compartmentalization at the megabase scale and partitioning of the genome into non-hierarchical TADs at the scale of 100 kb, which closely resembles the TAD profile in the bulk in situ Hi-C data. Over 40% of TAD boundaries are conserved between individual nuclei and possess a high level of active epigenetic marks. Polymer simulations demonstrate that chromatin folding is best described by the random walk model within TADs and is most suitably approximated by a crumpled globule build of Gaussian blobs at longer distances. We observe prominent cell-to-cell variability in the long-range contacts between either active genome loci or between Polycomb-bound regions, suggesting an important contribution of stochastic processes to the formation of the Drosophila 3D genome.

Isolation of microcell hybrid clones containing retroviral vector insertions into specific human chromosomes

1987 ◽  
Vol 7 (8) ◽  
pp. 2814-2820
Author(s):  
T G Lugo ◽  
B Handelin ◽  
A M Killary ◽  
D E Housman ◽  
R E Fournier
Keyword(s):  
High Efficiency ◽  
Human Fibroblasts ◽  
Retroviral Vector ◽  
Human Chromosomes ◽  
G418 Resistance ◽  
Microcell Hybrid ◽  
Dominant Selectable Marker ◽  
Hybrid Clones ◽  
Microcell Fusion

We sought an efficient means to introduce specific human chromosomes into stable interspecific hybrid cells for applications in gene mapping and studies of gene regulation. A defective amphotropic retrovirus was used to insert the gene conferring G418 resistance (neo), a dominant selectable marker, into the chromosomes of diploid human fibroblasts, and the marked chromosomes were transferred to mouse recipient cells by microcell fusion. We recovered five microcell hybrid clones containing one or two intact human chromosomes which were identified by karyotype and marker analysis. Integration of the neo gene into a specific human chromosome in four hybrid clones was confirmed by segregation analysis or by in situ hybridization. We recovered four different human chromosomes into which the G418 resistance gene had integrated: human chromosomes 11, 14, 20, and 21. The high efficiency of retroviral vector transformation makes it possible to insert selectable markers into any mammalian chromosomes of interest.

scholarly journals The presence and absence of periplasmic rings in bacterial flagellar motors correlates with stator type

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Mohammed Kaplan ◽  
Debnath Ghosal ◽  
Poorna Subramanian ◽  
Catherine M Oikonomou ◽  
Andreas Kjaer ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Pathogenic Bacteria ◽  
Bioinformatics Analysis ◽  
Cell Envelope ◽  
Shewanella Oneidensis ◽  
Flagellar Motor ◽  
Flagellar Motors ◽  
A Cell ◽  
Animal Hosts

The bacterial flagellar motor, a cell-envelope-embedded macromolecular machine that functions as a cellular propeller, exhibits significant structural variability between species. Different torque-generating stator modules allow motors to operate in different pH, salt or viscosity levels. How such diversity evolved is unknown. Here, we use electron cryo-tomography to determine the in situ macromolecular structures of three Gammaproteobacteria motors: Legionella pneumophila, Pseudomonas aeruginosa, and Shewanella oneidensis, providing the first views of intact motors with dual stator systems. Complementing our imaging with bioinformatics analysis, we find a correlation between the motor’s stator system and its structural elaboration. Motors with a single H+-driven stator have only the core periplasmic P- and L-rings; those with dual H+-driven stators have an elaborated P-ring; and motors with Na+ or Na+/H+-driven stators have both their P- and L-rings embellished. Our results suggest an evolution of structural elaboration that may have enabled pathogenic bacteria to colonize higher-viscosity environments in animal hosts.

scholarly journals Fibronectin expression is determined by the genotype of the transformed parental cells in heterokaryons between normal and transformed fibroblasts.

1979 ◽  
Vol 80 (1) ◽  
pp. 118-127 ◽  
Author(s):  
P Laurila ◽  
J Wartiovaara ◽  
S Stenman
Keyword(s):  
Cell Surface ◽  
Minimal Surface ◽  
Human Fibroblasts ◽  
Transformed Cells ◽  
Transformed Cell ◽  
Gene Dose ◽  
Fibronectin Expression ◽  
A Cell ◽  
Dose Dependent ◽  
Was Gene

The expression of fibronectin, a cell surface-associated transformation-sensitive glycoprotein, was studied in hetero- and homokaryons of normal and SV40-transformed human fibroblasts. In immunofluorescence, fibroblast homokaryons had an intense surface-associated and intracelluar fibronectin fluorescence similar to that of normal fibroblasts. Transformed cells and their homokaryons had a minimal surface-associated and a weak intracellular fibronectin fluorescence. In heterokaryons formed between transformed and normal fibroblasts, the expression of fibronectin fell within 24 h to the level of the transformed cell homokaryons. The change was detectable already at 3 h after fusion and was gene-dose dependent. These results show that the transformed genotype determines fibronectin expression in the heterokaryons.

Control of proliferin gene expression in serum-stimulated mouse cells

1987 ◽  
Vol 7 (6) ◽  
pp. 2080-2086
Author(s):  
D I Linzer ◽  
E L Wilder
Keyword(s):  
Protein Synthesis ◽  
S Phase ◽  
Mrna Levels ◽  
3T3 Cells ◽  
Serum Stimulation ◽  
Posttranscriptional Processing ◽  
A Cell ◽  
Mouse Cells ◽  
Stimulation Of

The serum-inducible expression of proliferin genes in BALB/c 3T3 cells was found to be dependent on both protein synthesis and an extended presence of serum in the medium. Even though no mature proliferin mRNA was detected in serum-starved cells, transcription of the proliferin genes occurred in these resting-cell cultures, indicating that posttranscriptional events may be important for regulating proliferin mRNA levels. These results suggest that protein synthesis after serum stimulation of quiescent mouse fibroblasts is required for posttranscriptional processing or stabilization of proliferin RNA. Proliferin RNA levels were found to be heterogeneous among serum-stimulated cells analyzed by in situ hybridization. This heterogeneity is probably due to asynchrony in the population and may point to a correlation between the time of proliferin expression and the time of entry of a cell into S phase.

Urinary TCP1-eta: A Cortical Damage Marker for the Pathophysiological Diagnosis and Prognosis of Acute Kidney Injury

2019 ◽  
Vol 174 (1) ◽  
pp. 3-15 ◽  
Author(s):  
Sandra M Sancho-Martínez ◽  
Fernando Sánchez-Juanes ◽  
Víctor Blanco-Gozalo ◽  
Miguel Fontecha-Barriuso ◽  
Laura Prieto-García ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Kidney Injury ◽  
Cortical Damage ◽  
Renal Tubular Cells ◽  
Tubular Necrosis ◽  
Diagnosis And Prognosis ◽  
A Cell ◽  
Renal Tubular ◽  
Dextran Solution

Abstract Acute kidney injury (AKI) is a serious syndrome with increasing incidence and health consequences, and high mortality rate among critically ill patients. Acute kidney injury lacks a unified definition, has ambiguous semantic boundaries, and relies on defective diagnosis. This, in part, is due to the absence of biomarkers substratifying AKI patients into pathophysiological categories based on which prognosis can be assigned and clinical treatment differentiated. For instance, AKI involving acute tubular necrosis (ATN) is expected to have a worse prognosis than prerenal, purely hemodynamic AKI. However, no biomarker has been unambiguously associated with tubular cell death or is able to provide etiological distinction. We used a cell-based system to identify TCP1-eta in the culture medium as a noninvasive marker of damaged renal tubular cells. In rat models of AKI, TCP1-eta was increased in the urine co-relating with renal cortical tubule damage. When kidneys from ATN rats were perfused in situ with Krebs-dextran solution, a portion of the urinary TCP1-eta protein content excreted into urine disappeared, and another portion remained within the urine. These results indicated that TCP1-eta was secreted by tubule cells and was not fully reabsorbed by the damaged tubules, both effects contributing to the increased urinary excretion. Urinary TCP1-eta is found in many etiologically heterogeneous AKI patients, and is statistically higher in patients partially recovered from severe AKI. In conclusion, urinary TCP1-eta poses a potential, substratifying biomarker of renal cortical damage associated with bad prognosis.

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