scholarly journals Dynamic Nature of Host-Pathogen Interactions inMycobacterium marinum Granulomas

2001 ◽  
Vol 69 (12) ◽  
pp. 7820-7831 ◽  
Author(s):  
Donna M. Bouley ◽  
Nafisa Ghori ◽  
K. Lynne Mercer ◽  
Stanley Falkow ◽  
Lalita Ramakrishnan
Keyword(s):  
Cell Activation ◽  
Morphological Changes ◽  
Tuberculous Infection ◽  
Dynamic Nature ◽  
Leopard Frogs ◽  
Transmission Electron ◽  
Phosphatase Cytochemistry ◽  
Phagocytic Killing

ABSTRACT Mycobacterium marinum causes long-term subclinical granulomatous infection in immunocompetent leopard frogs (Rana pipiens). These granulomas, organized collections of activated macrophages, share many morphological features with persistent human tuberculous infection. We examined organs of frogs with chronicM. marinum infection using transmission electron microscopy in conjunction with immunohistochemistry and acid phosphatase cytochemistry to better define the bacterium-host interplay during persistent infection. Bacteria were always found within macrophage phagosomes. These phagosomes were often fused to lysosomes, in sharp contrast to those formed during in vitro infection of J774 macrophage-like cells by M. marinum. The infected macrophages in frog granulomas showed various levels of activation, as evidenced by morphological changes, including epithelioid transformation, recent phagocytic events, phagolysosomal fusion, and disintegration of bacteria. Our results demonstrate that even long-term granulomas are dynamic environments with regard to the level of host cell activation and bacterial turnover and suggest a continuum between constantly replicating bacteria and phagocytic killing that maintains relatively constant bacterial numbers despite an established immune response. Infection with a mutant bacterial strain with a reduced capacity for intracellular replication shifted the balance, leading to a greatly reduced bacterial burden and inflammatory foci that differed from typical granulomas.

Involvement of extracellular calcium in gastric stimulation

1981 ◽  
Vol 241 (5) ◽  
pp. G365-G375
Author(s):  
C. D. Logsdon ◽  
T. E. Machen
Keyword(s):  
Morphological Changes ◽  
Phosphodiesterase Inhibitor ◽  
Ringer Solution ◽  
Tetraacetic Acid ◽  
Dibutyryl Camp ◽  
Long Term Effects ◽  
Gastric Stimulation ◽  
Transmission Electron

We have tested whether external Ca2+ is required for either initiation or maintenance of secretory parameters, including membrane elaboration of oxyntic cells, in frog gastric mucosa. Ca2+ was removed from in vitro mucosal preparations [by washing repeatedly in Ca2+-free Ringer solution and adding 0.1 mM ethylene glycol-bis(beta-aminoethylether)-N,N'-tetraacetic acid to the serosal solution] either before (i.e., resting tissues) or after addition of stimulants. Electrophysiology [transepithelial potential difference (PD) and resistance], morphology (morphometric analysis of transmission electron micrographs), and transport (H+ secretion) were monitored. La3+ (1 mM) was added to the mucosal solution to help maintain resistance and PD. La3+ decreased tissue shunt conductance during Ca2+-free conditions, as evidenced by a decreased mucosal-serosal flux of 22Na+, presumably by preserving tight-junction integrity. Secretion was elicited by histamine alone or in combination with dibutyryl cAMP and isobutylmethylxanthine (a phosphodiesterase inhibitor). External Ca2+ is not required for the initiation of H+ secretion or the accompanying morphological changes when the combined stimulants are used, whereas H+ secretion and the morphological change showed some Ca2+ dependency when histamine alone was used. Thus, histamine-elicited secretion seems to be more sensitive to Ca2+ removal than that brought about by the combined stimulants. Long-term effects of Ca2+-free solutions on resistance, PD, and H+ secretion can largely be explained by disruptive effects on tight junctions.

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.

scholarly journals Protein kinase D promotes plasticity-induced F-actin stabilization in dendritic spines and regulates memory formation

2015 ◽  
Vol 210 (5) ◽  
pp. 771-783 ◽  
Author(s):  
Norbert Bencsik ◽  
Zsófia Szíber ◽  
Hanna Liliom ◽  
Krisztián Tárnok ◽  
Sándor Borbély ◽  
...  
Keyword(s):  
Synaptic Plasticity ◽  
Protein Kinase ◽  
Dendritic Spines ◽  
Morphological Changes ◽  
Long Term Potentiation ◽  
Memory Formation ◽  
Protein Kinase D

Actin turnover in dendritic spines influences spine development, morphology, and plasticity, with functional consequences on learning and memory formation. In nonneuronal cells, protein kinase D (PKD) has an important role in stabilizing F-actin via multiple molecular pathways. Using in vitro models of neuronal plasticity, such as glycine-induced chemical long-term potentiation (LTP), known to evoke synaptic plasticity, or long-term depolarization block by KCl, leading to homeostatic morphological changes, we show that actin stabilization needed for the enlargement of dendritic spines is dependent on PKD activity. Consequently, impaired PKD functions attenuate activity-dependent changes in hippocampal dendritic spines, including LTP formation, cause morphological alterations in vivo, and have deleterious consequences on spatial memory formation. We thus provide compelling evidence that PKD controls synaptic plasticity and learning by regulating actin stability in dendritic spines.

Paracrystalline bundles of large tubules, induced in vitro by Mebendazole in Cysticercus cellulosae

Parasitology ◽  
1981 ◽  
Vol 83 (3) ◽  
pp. 513-518 ◽  
Author(s):  
J. P. Laclette ◽  
Marie Therese Merchant ◽  
Kaethe Willms ◽  
L. Cañedo
Keyword(s):  
Electron Microscopy ◽  
Culture Medium ◽  
Morphological Changes ◽  
Bladder Wall ◽  
Secretory Cells ◽  
External Diameter ◽  
Nematode Larvae ◽  
Transmission Electron ◽  
Cysticercus Cellulosae

SUMMARYThe effect of the anthelmintic Mebendazole on Cysticercus cellulosae maintained in culture medium was studied by transmission electron microscopy. In addition to the well-known morphological changes induced by Mebendazole in other cestode and nematode larvae, it also induced the cytoplasmic appearance of paracrystalline bundles in the secretory cells of the bladder wall. These bundles were formed by groups of large parallel tubules arranged in a hexagonal-like pattern. The tubules, which had an external diameter of about 50 nm and a length that might exceed 5 μm, were surrounded by a matrix and a distance between neighbouring tubules of 80–120 nm centre to centre was estimated. The tubules were stable to colchicine and low temperature. The temporary appearance of bundles is described and some alternative explanations on their origin are advanced.

scholarly journals Effects of Long-Term Citrate Treatment in the PC3 Prostate Cancer Cell Line

2019 ◽  
Vol 20 (11) ◽  
pp. 2613 ◽  
Author(s):  
Carmen Caiazza ◽  
Massimo D’Agostino ◽  
Fabiana Passaro ◽  
Deriggio Faicchia ◽  
Massimo Mallardo ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cell Line ◽  
Morphological Changes ◽  
Short Form ◽  
Acute Administration ◽  
In Vivo Models ◽  
Pc3 Cells ◽  
Resistant Cells

Acute administration of a high level of extracellular citrate displays an anti-proliferative effect on both in vitro and in vivo models. However, the long-term effect of citrate treatment has not been investigated yet. Here, we address this question in PC3 cells, a prostate-cancer-derived cell line. Acute administration of high levels of extracellular citrate impaired cell adhesion and inhibited the proliferation of PC3 cells, but surviving cells adapted to grow in the chronic presence of 20 mM citrate. Citrate-resistant PC3 cells are significantly less glycolytic than control cells. Moreover, they overexpress short-form, citrate-insensitive phosphofructokinase 1 (PFK1) together with full-length PFK1. In addition, they show traits of mesenchymal-epithelial transition: an increase in E-cadherin and a decrease in vimentin. In comparison with PC3 cells, citrate-resistant cells display morphological changes that involve both microtubule and microfilament organization. This was accompanied by changes in homeostasis and the organization of intracellular organelles. Thus, the mitochondrial network appears fragmented, the Golgi complex is scattered, and the lysosomal compartment is enlarged. Interestingly, citrate-resistant cells produce less total ROS but accumulate more mitochondrial ROS than control cells. Consistently, in citrate-resistant cells, the autophagic pathway is upregulated, possibly sustaining their survival. In conclusion, chronic administration of citrate might select resistant cells, which could jeopardize the benefits of citrate anticancer treatment.

scholarly journals Differentiation of a teratocarcinoma line: preferential development of cholinergic neurons.

1981 ◽  
Vol 88 (1) ◽  
pp. 57-66 ◽  
Author(s):  
S E Pfeiffer ◽  
H Jakob ◽  
K Mikoshiba ◽  
P Dubois ◽  
J L Guenet ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Cholinergic Neurons ◽  
Carcinoma Cells ◽  
Sodium Influx ◽  
Average Cell ◽  
Transmission Electron ◽  
Neuronal Processes ◽  
Embryonic Antigen ◽  
Average Cell Volume

A line of embryonal carcinoma cells, PCC7-S, established in vitro from a spontaneous testicular teratocarcinoma, has been studied. Upon removing the cells from a low density monolayer culture system and permitting the cells to form aggregates in suspension, we observed a change of several physical and biochemical parameters: (a) reduction in average cell volume, (b) blockage and accumulation of cells in G1, (c) rise in secreted protease activity, (d) rise in acetylcholinesterase and choline acetyltransferase activities, and (e) disappearance of embryonic antigen F9. Although PCC7 aggregates did not undergo substantial morphological changes while suspended, when aggregates 4 or more days old were allowed to attach to plastic tissue culture dishes, substantial neurite outgrowth occurred over the next 1-3 d. This process was markedly enhanced by the addition to the growth medium of carboxymethylcellulose and inhibitors of DNA synthesis. Transmission electron microscopy disclosed a neurite ultrastructure consistent with that of neuronal processes. A veratridine-stimulated, tetrodotoxin-blocked sodium influx of 100 nmol/min per mg protein was also observed in these differentiated surface cultures. This cell line is discussed in terms of its utility for the study of early events leading to a commitment to cellular differentiation, as well as for the investigation of terminal differentiation to cholinergic neurons.

Ultrastructural Characterization of Platelet-Activating Factor-Stimulated Human Eosinophils from Patients with Asthma

1993 ◽  
Vol 84 (4) ◽  
pp. 391-399 ◽  
Author(s):  
Claus Kroegel ◽  
Ann Dewar ◽  
Tatsuo Yukawa ◽  
Per Venge ◽  
Peter J. Barnes ◽  
...  
Keyword(s):  
Morphometric Analysis ◽  
Morphological Changes ◽  
Shape Change ◽  
Platelet Activating Factor ◽  
Eosinophil Cationic Protein ◽  
Cell Periphery ◽  
Cationic Protein ◽  
Asthmatic Patients ◽  
Transmission Electron

1. Purified human eosinophils from asthmatic patients were stimulated with platelet-activating factor in vitro and examined for morphological changes by transmission electron and light microscopy. Changes were also evaluated by morphometric analysis and were related to the platelet-activating factor-stimulated release of granular eosinophil cationic protein. 2. Stimulation of eosinophils with platelet-activating factor induced a dose-dependent shape change, including the elongation of cells, loss of microvilli and the formation of lamellipodia. This effect was maximal at 25 min and was reversible. 3. Stimulation with platelet-activating factor also induced granule movement to the cell periphery and fusion of adjacent granules. Granules became swollen and vesiculated, whereas both the matrix and core showed evidence of solubilization. 4. There was a time-dependent secretion of eosinophilic cationic protein from human eosinophils upon stimulation with platelet-activating factor which occurred without significant lactate dehydrogenase release. 5. Morphometric analysis of the transmission electron micrographs indicated a significant reduction in cytoplasmic area after 10 min of incubation with platelet-activating factor from 39.0 ± 1.7 μm2 for untreated eosinophils to 33.2 ± 2.3 μm2 (P < 0.02) for platelet-activating factor-treated cells, underscoring the observation that the cells change from spherical to ellipsoidal. No significant increase in the perimeter of the cells was found. 6. The number of granule-profiles in platelet-activating factor-stimulated eosinophils was slightly reduced when compared with control, and an increase in granule area was observed 10 min after platelet-activating factor challenge (0.215 ± 0.011 μm2 versus 0.246 ± 0.016 μm2). 7. Human eosinophils from patients with asthma stimulated with platelet-activating factor undergo both cellular and granular alterations and reorganization which parallel the release of granular eosinophil basic protein.

scholarly journals Antileishmanial Activity of a Linalool-Rich Essential Oil from Croton cajucara

2003 ◽  
Vol 47 (6) ◽  
pp. 1895-1901 ◽  
Author(s):  
Maria do Socorro S. Rosa ◽  
Ricardo R. Mendonça-Filho ◽  
Humberto R. Bizzo ◽  
Igor de Almeida Rodrigues ◽  
Rosangela Maria A. Soares ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Essential Oil ◽  
Mammalian Cells ◽  
Morphological Changes ◽  
Peritoneal Macrophages ◽  
Transmission Electron ◽  
Low Concentrations ◽  
Mouse Peritoneal Macrophages ◽  
Croton Cajucara

ABSTRACT The in vitro leishmanicidal effects of a linalool-rich essential oil from the leaves of Croton cajucara against Leishmania amazonensis were investigated. Morphological changes in L. amazonensis promastigotes treated with 15 ng of essential oil per ml were observed by transmission electron microscopy; leishmanial nuclear and kinetoplast chromatin destruction, followed by cell lysis, was observed within 1 h. Pretreatment of mouse peritoneal macrophages with 15 ng of essential oil per ml reduced by 50% the interaction between these macrophages and L. amazonensis, with a concomitant increase by 220% in the level of nitric oxide production by the infected macrophages. Treatment of preinfected macrophages with 15 ng of essential oil per ml reduced by 50% the interaction between these cells and the parasites, which led to a 60% increase in the amount of nitric oxide produced by the preinfected macrophages. These results provide new perspectives on the development of drugs with activities against Leishmania, as linalool-rich essential oil is a strikingly potent leishmanicidal plant extract (50% lethal doses, 8.3 ng/ml for promastigotes and 8.7 ng/ml for amastigotes) which inhibited the growth of L. amazonensis promastigotes at very low concentrations (MIC, 85.0 pg/ml) and which presented no cytotoxic effects against mammalian cells.

Dietary regulation of intestinal brush-border sugar and amino acid transport in carnivores

1991 ◽  
Vol 261 (4) ◽  
pp. R793-R801 ◽  
Author(s):  
R. K. Buddington ◽  
J. W. Chen ◽  
J. M. Diamond
Keyword(s):  
Brush Border ◽  
Sugar Transport ◽  
Nutrient Transporters ◽  
Sugar Transporters ◽  
Dietary Regulation ◽  
Leopard Frogs ◽  
Intestinal Brush Border ◽  
Carbohydrate Levels

The ability of omnivores and herbivores to regulate reversibly their intestinal brush-border nutrient transporters is functionally related to the unpredictably variable composition of their natural diets. To determine whether carnivores are able similarly to regulate the activities of their intestinal nutrient transporters, we fed to three species of vertebrates that are carnivorous as adults (cats, mink, and leopard frogs) diets with either at least 50% digestible carbohydrate or with negligible carbohydrate levels. Rates of transport for the sugars glucose and fructose and the amino acids (AAs) aspartate, leucine, lysine, and proline were measured throughout the intestine (only proline and glucose in the frogs) by an in vitro everted-sleeve method. Although all three species consume much carbohydrate during early development, only the mink was able to regulate sugar transporter activity in response to changes in levels of dietary carbohydrate. In contrast, the sugar transporters of the cat were unresponsive to varying carbohydrate levels, and long-term feeding of a high-carbohydrate diet caused down-regulation of sugar transport in frogs. Of the three species, only the mink is a member of a family that includes omnivorous species, whereas all members of the families to which the cat and frog belong are carnivorous as adults. All three species were able to regulate rates of AA transport, though the patterns and magnitude of the responses differed between species as well as between AAs, suggesting independent regulation of some AA transporters.(ABSTRACT TRUNCATED AT 250 WORDS)

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