Effect of temperature and divalent cations on the substratum attachment of rat hepatocytes in vitro

1978 ◽  
Vol 34 (1) ◽  
pp. 117-131
Author(s):  
P.O. Seglen ◽  
R. Gjessing
Keyword(s):  
Cytochalasin B ◽  
Arrhenius Plot ◽  
Divalent Cations ◽  
Rat Hepatocytes ◽  
Effect Of Temperature ◽  
Temperature Sensitive ◽  
Dextran Sulphate ◽  
Cell Binding ◽  
Better Than

The attachment of rat hepatocytes to polystyrene-adsorbed serum protein is relatively insensitive to inhibitors such as dextran sulphate, cycloheximide, colchicine and cytochalasin B, and enzymes like trypsin and neuraminidase, but it is strongly dependent on divalent cations. Mg2+ supports attachment better than Ca2+, but a combination of both is required for maximal attachment. The attachment is very temperature-sensitive, with a biphasic Arrhenius plot indicating an activation energy of 123 kJ/mol above 34 degrees C and 374 kJ/mol below 34 degrees C. The adsorbed attachment-promoting serum factor is inactivated by trypsin, or by Ca2+-dependent proteases which contaminate commercial preparations of collagenase. The adsorbed factor is resistant to treatment with glutaraldehyde, neuraminidase and heating to 90 degrees C, whereas the same factor in the unadsorbed state (in serum) is destroyed by heating to 70 degrees C. The factor in serum is unable to compete with the adsorbed factor for cell binding, hence it would appear that adsorption to polystyrene induces the active, heat-resistant conformation of the factor.

scholarly journals Insights in Behavior of Variably Formulated Alginate-Based Microcapsules for Cell Transplantation

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Pia Montanucci ◽  
Silvia Terenzi ◽  
Claudio Santi ◽  
Ilaria Pennoni ◽  
Vittorio Bini ◽  
...  
Keyword(s):  
Divalent Cations ◽  
Chemical Properties ◽  
Live Cells ◽  
High Performing ◽  
Physical Chemical ◽  
Degenerative Disorders ◽  
Selection Of ◽  
Better Than

Alginate-based microencapsulation of live cells may offer the opportunity to treat chronic and degenerative disorders. So far, a thorough assessment of physical-chemical behavior of alginate-based microbeads remains cloudy. A disputed issue is which divalent cation to choose for a high performing alginate gelling process. Having selected, in our system, high mannuronic (M) enriched alginates, we studied different gelling cations and their combinations to determine their eventual influence on physical-chemical properties of the final microcapsules preparation,in vitroandin vivo. We have shown that used of ultrapure alginate allows for high biocompatibility of the formed microcapsules, regardless of gelation agents, while use of different gelling cations is associated with corresponding variable effects on the capsules’ basic architecture, as originally reported in this work. However, only the final application which the capsules are destined to will ultimately guide the selection of the ideal, specific gelling divalent cations, since in principle there are no capsules that are better than others.

scholarly journals Insulin biosynthesis in the bullhead, Ictalurus nebulosus, and the effect of temperature

1973 ◽  
Vol 134 (3) ◽  
pp. 753-761 ◽  
Author(s):  
Margaret L. Moule ◽  
Cecil C. Yip
Keyword(s):  
Qualitative Difference ◽  
Gel Filtration ◽  
Effect Of Temperature ◽  
Insulin Biosynthesis ◽  
Temperature Sensitive ◽  
Bicarbonate Buffer ◽  
Control Tissue ◽  
Ictalurus Nebulosus ◽  
Lower Temperature

Insulin biosynthesis in the brown bullhead, Ictalurus nebulosus (Le Sueur), was studied by measuring the incorporation in vitro of [3H]leucine into proteins of the principal islet. The tissue was incubated for 6–15h in Krebs–Ringer bicarbonate buffer with [3H]leucine, supplemented with amino acids and glucose. Proteins, precipitated with trichloroacetic acid and extracted with acid ethanol, were separated by gel-filtration on Biogel P-30 in 3m-acetic acid. Three major components were found after incubation of the islets at 22°C. On the basis of the results of sulphitolysis, biological activity and the demonstrated precursor–product relationship, components I and II were identified as proinsulin and insulin respectively. The third component was not identified. At 12°C, [3H]leucine was incorporated only into proinsulin. No radioactivity was found in insulin or the unidentified component III at 12°C as was found after incubation at 22°C. When the temperature was lowered from 22° to 12°C after 3h of a 15h incubation, decreased conversion of proinsulin into insulin resulted at the lower temperature compared with the control tissue maintained at 22°C. When the temperature was raised from 12° to 22°C at 3h of a 15h incubation, conversion of proinsulin into insulin occurred. No conversion occurred in the control tissue with the temperature maintained at 12°C. No qualitative difference in the incorporation of [3H]leucine into proinsulin and its conversion into insulin at 12° and 22°C could be demonstrated between islet tissue from fish acclimated to less than 12°C or to 22°C. The results suggest that the enzyme(s) responsible for converting proinsulin into insulin in the bullhead may be temperature sensitive with low activity at 12°C.

Effect of Temperature on Endplate Potential Rundown and Recovery in Rat Diaphragm

2001 ◽  
Vol 85 (5) ◽  
pp. 2070-2075 ◽  
Author(s):  
Michelle Moyer ◽  
Erik van Lunteren
Keyword(s):  
Neuromuscular Junction ◽  
Effect Of Temperature ◽  
Temperature Sensitive ◽  
Enzymatic Reactions ◽  
Rat Diaphragm ◽  
Intermittent Stimulation ◽  
Vesicle Recycling ◽  
Endplate Potential ◽  
Stimulation Period

The amplitude of neuromuscular junction end-plate potentials (EPPs) decreases quickly within a train but recovers nearly completely from train to train during intermittent stimulation. Rundown has been shown to be dependent not only on the rate of transmitter release but also on the rate of replenishment of the depleted neurotransmitter at the site of release. Two groups of processes have been proposed for synaptic vesicle recycling, both of which involve multiple energy-requiring steps and enzymatic reactions and which therefore would be expected to be very temperature-sensitive. The present study tested the hypothesis that low temperature therefore increases the rate of EPP amplitude rundown. Studies were performed in vitro on rat diaphragm and used μ-conotoxin to allow normal-sized EPPs to be recorded from intact fibers. EPP amplitude rundown during intermittent stimulation at 20 and 50 Hz (duty cycle 333 ms) was greater at 20°C than it was at 37°C. Initially, temperature affected only intra-train rundown but, over longer periods of stimulation, both intra- and inter-train rundown were significantly accelerated by cold temperature. Cumulative EPP amplitudes were calculated by successively adding the amplitudes of each EPP during the stimulation period to provide an estimate of total neurotransmitter release in the neuromuscular junction. The cumulative EPP amplitude was significantly lower at 20°C than it was at 37°C during both 20 and 50 Hz stimulation. These data indicate that the mechanism involved in EPP amplitude rundown and recovery is temperature-sensitive, with a greater decrement in EPP amplitude at cold than at warm temperatures.

scholarly journals Temperature sensitivity differs between heart and red muscle mitochondria in mahi-mahi (Coryphaena hippurus)

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Gigi Y. Lau ◽  
Georgina K. Cox ◽  
John D. Stieglitz ◽  
Daniel D. Benetti ◽  
Martin Grosell
Keyword(s):  
Heart Mitochondria ◽  
Effect Of Temperature ◽  
Temperature Sensitive ◽  
Temperature Changes ◽  
Coryphaena Hippurus ◽  
Wide Range ◽  
Irreversible Effects ◽  
Effects Of Temperature ◽  
Lower Temperature

Abstract Maintaining energy balance over a wide range of temperatures is critical for an active pelagic fish species such as the mahi-mahi (Coryphaena hippurus), which can experience rapid changes in temperature during vertical migrations. Due to the profound effect of temperature on mitochondrial function, this study was designed to investigate the effects of temperature on mitochondrial respiration in permeabilized heart and red skeletal muscle (RM) fibres isolated from mahi-mahi. As RM is thought to be more anatomically isolated from rapid ambient temperature changes compared to the myocardium, it was hypothesized that heart mitochondria would be more tolerant of temperature changes through a greater ability to match respiratory capacity to an increase in temperature and to maintain coupling, when compared to RM mitochondria. Results show that heart fibres were more temperature sensitive and increased respiration rate with temperature increases to a greater degree than RM. Respiratory coupling ratios at the three assay temperatures (20, 26, and 30 °C), revealed that heart mitochondria were less coupled at a lower temperature (26 °C) compared to RM mitochondria (30 °C). In response to an in vitro acute temperature challenge, both tissues showed irreversible effects, where both heart and RM increased uncoupling whether the assay temperature was acutely changed from 20 to 30 °C or 30 to 20 °C. The findings from this study indicate that mahi-mahi heart mitochondria were more temperature sensitive compared to those from RM.

scholarly journals Fever and immunoregulation. III. Hyperthermia augments the primary in vitro humoral immune response.

1983 ◽  
Vol 157 (4) ◽  
pp. 1229-1238 ◽  
Author(s):  
H D Jampel ◽  
G W Duff ◽  
R K Gershon ◽  
E Atkins ◽  
S K Durum
Keyword(s):  
Immune Response ◽  
Cell Response ◽  
Direct Action ◽  
Interleukin 1 ◽  
Effect Of Temperature ◽  
Temperature Sensitive ◽  
Humoral Immune ◽  
Fever Response ◽  
And Function

We have examined the possibility that hyperthermia, such as that occurring during fever, may benefit the immune response. The effect of temperature on the in vitro immune response of unprimed murine spleen cells against the antigen sheep erythrocytes was tested. Hyperthermia potently augmented the plaque-forming cell response. Temperature-sensitive events occurred early in the culture period. Subsets of lymphocytes were independently assessed for effects of temperature on their activation and function. We showed that the beneficial effect of elevated temperature on the plaque-forming cell response probably occurs during the priming stage of T helper cells, and neither improves the delivery of help or the activation of B cells, nor impairs suppressor T cell generation or function. We propose that this powerful immunopotentiating effect of hyperthermia may account for the selective value of the fever response. This suggests taht the monokine interleukin 1, which is the endogenous mediator of fever, may promote immune responses both through a direct action on lymphocytes, and indirectly by an action on the central nervous system resulting in fever.

Effect of temperature treatment on survival of Heterodera glycines and its associated fungi and bacteria

Nematology ◽  
2016 ◽  
Vol 18 (7) ◽  
pp. 845-855 ◽  
Author(s):  
Weiming Hu ◽  
Senyu Chen ◽  
Xingzhong Liu
Keyword(s):  
Soybean Cyst Nematode ◽  
Heterodera Glycines ◽  
Temperature Treatment ◽  
Effect Of Temperature ◽  
Suppressive Soil ◽  
Freezing Soil ◽  
Bacteria And Fungi ◽  
Nematode Suppressive Soil ◽  
Better Than

In studies of nematode-suppressive soil and plant-parasitic nematode management, it is often desirable to kill nematodes in the soil but keep the microbial community alive. The effect of temperature treatment on survival of Heterodera glycines, the soybean cyst nematode (SCN), and associated fungi and bacteria was investigated. Extracted eggs and cysts, and cysts in soil were subjected to treatments of temperatures ranging from −80 to 55°C for 1 to 24 h. Nematode survival was determined by hatching in vitro and by infectivity and development in soybean, and fungal survival was determined by plating the eggs or cysts on potato dextrose agar. The nematodes survived well between −20 and 45°C, but could not survive at −80 or 48°C and above, while some nematodes were killed after heat treatment of 46°C. By contrast, fungi survived well in the cysts at −80°C, and also much better than nematodes at the high temperatures. Glasshouse studies demonstrated that both bacteria and fungi survived well in the soil treated with −80°C. Transferring 5% of −80°C-treated soil to autoclaved soil could effectively establish nematode suppressiveness. Our study demonstrated that freezing soil at −80°C can kill SCN but maintain nematode suppressiveness, and the soil treatment can improve the method for nematode-suppressive soil evaluation.

scholarly journals Intracellular segregation of asialoglycoproteins and their receptor: a prelysosomal event subsequent to dissociation of the ligand-receptor complex.

1984 ◽  
Vol 98 (2) ◽  
pp. 375-381 ◽  
Author(s):  
A W Wolkoff ◽  
R D Klausner ◽  
G Ashwell ◽  
J Harford
Keyword(s):  
Cytochalasin B ◽  
Monolayer Culture ◽  
Rat Hepatocytes ◽  
Endocytic Pathway ◽  
Temperature Sensitive ◽  
Ligand Complex ◽  
Receptor Ligand ◽  
Reduced Temperature ◽  
Two Temperature ◽  
Ionophore Monensin

Rat hepatocytes in monolayer culture rapidly internalized asialoglycoproteins and the receptors to which they are bound. Subsequent to endocytosis, the receptor-ligand complex is dissociated within an acidic endosome (Harford, J., K. Bridges, G. Ashwell, and R. D. Klausner, 1983, J. Biol. Chem. 258:3191-3197; Harford, J., A. W. Wolkoff, G. Ashwell, and R. D. Klausner, 1983, J. Cell Biol. 96:1824-1828). Here we show that addition of the proton ionophore monensin to the cells after dissociation has occurred results in intracellular rebinding of ligand molecules. With increasing time inside the cell, the ability of ligand to reassociate with receptor progressively decreases consistent with a segregation of receptor and ligand. The combination of colchicine and cytochalasin B appears to retard the process of segregation. In contrast, removal of sodium from the medium, while inhibiting degradation of ligand, does not affect the decrease in monensin-mediated rebinding. Nonetheless, both sodium deprivation and treatment with colchicine plus cytochalasin B result in the ligand remaining in a low density, nonlysosomal subcellular fraction. Thus, segregation, like dissociation, appears to occur in a pre-lysosomal endocytic compartment. Perturbation of the endocytic pathway by reduced temperature (18 degrees C) was also explored. Our data are consistent with two temperature-sensitive steps: receptor-ligand dissociation is inhibited and there is an independent temperature-sensitive step involved in delivery of ligand to lysosomes. This second effect was localized as being beyond the point in the pathway sensitive to sodium deprivation.

Use of Isolated Periportal and Perivenous Rat Hepatocytes for Studying the Acinar Heterogeneity of Xenobiotic Metabolism: Cytotoxicity of Allyl Alcohol

1988 ◽  
Vol 15 (3) ◽  
pp. 213-218
Author(s):  
Kai E. Penttilä
Keyword(s):  
Allyl Alcohol ◽  
Rat Hepatocytes ◽  
Cell Types ◽  
High Rate ◽  
Ion Content ◽  
Alcohol Dehydrogenase Activity ◽  
Collagenase Perfusion ◽  
Better Than

The periportal hepatotoxicity of allyl alcohol (AlOH) was investigated by studying its metabolism and cytotoxicity in suspensions of periportal (pp) and perivenous (pv) rat hepatocytes isolated by digitonin-collagenase perfusion. No marked difference in alcohol dehydrogenase activity between the cell types was observed. The cells also oxidised AlOH at about equal rates. AlOH depleted cellular glutathione by about 95% within 10 minutes in both cell types, but was partially restored during subsequent incubation. The pp cells suffering from AlOH toxicity in vivo tended to resist AlOH in vitro better than pv hepatocytes, as judged from the measurement of cellular ATP and K+ ion content, and LDH leakage. It is suggested that the oxidation of AlOH may be restricted to the pp region in intact liver simply because of the high rate of uptake and oxidation of AlOH by the liver tissue.

Immunoenzymatic demonstration of the simultaneous presence of transferrin, hemopexin and albumin in a same hepatocyte and their ultrastructural localization

1978 ◽  
Vol 36 (2) ◽  
pp. 88-89
Author(s):  
M. Kraemer ◽  
J. Foucrier ◽  
J. Vassy ◽  
M.T. Chalumeau
Keyword(s):  
Plasma Proteins ◽  
Rat Hepatocytes ◽  
Ultrastructural Localization ◽  
Carrier Proteins ◽  
Normal Cells ◽  
Adult Rat ◽  
Adult Rat Hepatocytes ◽  
Monospecific Antisera ◽  
Different Levels

Some authors using immunofluorescent techniques had already suggested that some hepatocytes are able to synthetize several plasma proteins. In vitro studies on normal cells or on cells issued of murine hepatomas raise the same conclusion. These works could be indications of an hepatocyte functionnal non-specialization, meanwhile the authors never give direct topographic proofs suitable with this hypothesis.The use of immunoenzymatic techniques after obtention of monospecific antisera had seemed to us useful to bring forward a better knowledge of this problem. We have studied three carrier proteins (transferrin = Tf, hemopexin = Hx, albumin = Alb) operating at different levels in iron metabolism by demonstrating and localizing the adult rat hepatocytes involved in their synthesis.Immunological, histological and ultrastructural methods have been described in a previous work.

The development of dormancy in bulblets of Lilium speciosum generated in vitro. II. The effect of temperature

1990 ◽  
Vol 80 (3) ◽  
pp. 431-436 ◽  
Author(s):  
Isabelle Delvallee ◽  
Annie Paffen ◽  
Geert-Jan De Klerk
Keyword(s):  
Effect Of Temperature ◽  
Lilium Speciosum
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