In vivo characterization of thermal stabilities of Aeropyrum pernix cellular components by differential scanning calorimetry

2007 ◽  
Vol 53 (9) ◽  
pp. 1038-1045 ◽  
Author(s):  
Igor Milek ◽  
Miha Črnigoj ◽  
Nataša Poklar Ulrih ◽  
Gönül Kaletunç
Keyword(s):  
Heat Treatment ◽  
Differential Scanning Calorimetry ◽  
Optical Data ◽  
Lag Phase ◽  
Scanning Calorimetry ◽  
Thermal Stabilities ◽  
Whole Cell ◽  
Whole Cells ◽  
Aeropyrum Pernix ◽  
Cellular Components

Revival studies of Aeropyrum pernix show that the viability of cells and cell recovery after heat treatment depends on the temperature of treatment. Differential scanning calorimetry (DSC) is used to analyze the relative thermal stabilities of cellular components of A. pernix and to identify the cellular components responsible for the observed lag phase and reduced maximum growth following a heat treatment. DSC thermograms show 5 visible endothermic transitions with 2 major transitions. DSC analysis of isolated crude ribosomes aids the assignment of the 2 major peaks observed in whole-cell thermograms to denaturation of ribosomal structures. A comparison of partial and immediate full rescan thermograms of A. pernix whole cells indicates that both major peaks represent irreversible thermal transitions. A DNA peak is also identified in the whole-cell thermogram by comparison with the optical data of isolated pure DNA. DNA melting is shown to be irreversible in dilute solution, whereas it is partially reversible in whole cells, owing at least in part, to restricted volume effects. In contrast to mesophilic organisms, hyperthermophilic A. pernix ribosomes are more thermally stable than DNA, but in both organisms, irreversible changes leading to cell death occur owing to ribosomal denaturation.

scholarly journals Evaluation of the Heat Inactivation of Escherichia coli and Lactobacillus plantarum by Differential Scanning Calorimetry

2002 ◽  
Vol 68 (11) ◽  
pp. 5379-5386 ◽  
Author(s):  
Jaesung Lee ◽  
Gönül Kaletunç
Keyword(s):  
Escherichia Coli ◽  
Heat Treatment ◽  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Lactobacillus Plantarum ◽  
Plate Count ◽  
Scanning Calorimetry ◽  
Whole Cells ◽  
E Coli ◽  
Thermal Stability Of

ABSTRACT Differential scanning calorimetry (DSC) is used to evaluate the thermal stability and reversibility after heat treatment of transitions associated with various cellular components of Escherichia coli and Lactobacillus plantarum. The reversibility and the change in the thermal stability of individual transitions are evaluated by a second temperature scan after preheating in the DSC to various temperatures between 40 and 130°C. The viability of bacteria after a heat treatment between 55 and 70°C in the DSC is determined by both plate count and calorimetric data. The fractional viability values based on calorimetric and plate count data show a linear relationship. Viability loss and the irreversible change in DSC thermograms of pretreated whole cells are highly correlated between 55 and 70°C. Comparison of DSC scans for isolated ribosomes shows that the thermal stability of E. coli ribosomes is greater than that of L. plantarum ribosomes, consistent with the greater thermal tolerance of E. coli observed from viability loss and DSC scans of whole cells.

Synthesis and Properties of New Poly( Amide-Imide)s Based on Imide Dicarboxylic Acid

2011 ◽  
Vol 332-334 ◽  
pp. 1722-1726 ◽  
Author(s):  
Sheng Chen ◽  
Qing Kang Zheng ◽  
Zhen Bao Li ◽  
Xin Lei Wang ◽  
Jian Wu Lan
Keyword(s):  
Differential Scanning Calorimetry ◽  
Dicarboxylic Acid ◽  
Diphenyl Ether ◽  
Aminobenzoic Acid ◽  
Trimellitic Anhydride ◽  
Scanning Calorimetry ◽  
Thermal Stabilities ◽  
Glass Transition Temperatures ◽  
Weight Losses ◽  
Cast Films

Two kinds of imide dicarboxylic acid monomers, 4,4'-bis(trimellitimido) diphenyl ether Ⅰ and p-trimellitimido-benzoic acid Ⅱ were successfully synthesized from 4,4'-diaminodiphenyl ether and p-aminobenzoic acid with trimellitic anhydride respectively.and used to synthesize a series of new aromatic poly(amide-imide)s (PAIs) by the tri-phenyl phosphite-activated polycondensation method. The preparation of PAIs was carried out using triphenyl phosphate and pyridine symtem. The PAIs had inherent viscosities of 0.55–1.46 dL g-1. PAI films were obtained by casting their N-Methyl-2-pyrrolidone (NMP) solution. Their cast films had tensile strengths ranging from 37.4 to 83.9 MPa. The glass-transition temperatures (measured by differential scanning calorimetry) were in the range of 265-310°C. According to thermogravimetric analysis, the polymers were fairly stable up to temperature around 420°C, and 10% weight losses in the temperature range of 474-550°C in nitrogen, that showed good thermal stabilities of these polymers.

Synthesis of nanocomposite coating of electrodeposed amorphic layers of the Ni–P–W system

2020 ◽  
pp. 53-60
Author(s):  
A. V. Krasikov
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Differential Scanning Calorimetry ◽  
Phase Composition ◽  
Diffraction Analysis ◽  
Nanocomposite Coating ◽  
Nanocrystalline Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

The processes of the formation of the nanocomposite coating of Ni–11.5% P–5%W were studied during the heat treatment of amorphous electrodeposited layers. Using the method of differential scanning calorimetry, the temperature of the onset of crystallization of the nanocrystalline phase Ni3P was determined. X-ray diffraction analysis showed that heat treatment produces Ni3P phosphides and, presumably, Ni5P2, the size of which, according to electron microscopy, is 5–50 nm. The influence of the duration of heat treatment on the phase composition and microhardness of coatings is investigated.

scholarly journals Solvate Formation of Bis(demethoxy)curcumin: Screening and Characterization

Crystals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 407 ◽  
Author(s):  
Lina Yuan ◽  
Heike Lorenz
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermogravimetric Analysis ◽  
Mass Loss ◽  
Storage Conditions ◽  
Stoichiometric Ratio ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Thermal Stabilities ◽  
X Ray ◽  
Ambient Storage

Solvate formation of bis(demethoxy)curcumin (BDMC) was screened. Six solvates were obtained out of the nineteen solvents investigated. In the present work, three solvates, i.e., BDMC-tetrahydrofuran (THF), BDMC-1,4-dioxane (DIO) and BDMC-dimethyl sulfoxide (DMSO), were thoroughly studied. Their desolvation processes were characterized by temperature-resolved powder X-ray diffraction (TR-PXRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and hot-stage microscopy (HSM). TR-PXRD shows that all the solvates desolvate as the mother BDMC form and no new polymorph could be obtained. The stoichiometric ratio of solvates was calculated via the mass loss of solvents determined by TGA. The thermal stabilities of the solvates were obtained from DSC data and followed the order: BDMC-DMSO > -THF > -DIO. Moreover, stability performances at ambient storage conditions recorded by PXRD show that BDMC-DMSO was stable over three months.

scholarly journals Thermal behavior and thermodynamic parameters of some complexes of biologically active nucleic acid constituents

2021 ◽  
Vol 12 (2) ◽  
pp. 078-108
Author(s):  
M. S. Masoud ◽  
M. Sh. Ramadan ◽  
A. M. Sweyllam ◽  
A. M. Ramadan ◽  
M. H. Al-Saify
Keyword(s):  
Differential Scanning Calorimetry ◽  
Nucleic Acid ◽  
Thermogravimetric Analysis ◽  
Thermal Behavior ◽  
Thermodynamic Parameters ◽  
Biologically Active ◽  
Molecular Configuration ◽  
Scanning Calorimetry ◽  
Thermal Stabilities ◽  
Mechanism Of Decomposition

The thermal behavior of some complexes derived from biologically nucleic acid constituents has been studied applying differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques. Thermodynamic parameters, decompositions and thermal stabilities are calculated and explained. All the complexes gave exothermic peaks with -ve signs for change of entropy values, ΔS which indicate that the activated transition states are more ordered, i.e. in a less random molecular configuration than the reacting complexes. TGA gives the mechanism of decomposition.

scholarly journals Investigation of the films based on the uronate polysaccharides by the method of differential scanning calorimetry

2018 ◽  
Vol 12 (3) ◽  
Author(s):  
N. Коndratjuk ◽  
Ye. Pyvovarov ◽  
Т. Stepanova ◽  
Yu. Matsuk
Keyword(s):  
Heat Treatment ◽  
Differential Scanning Calorimetry ◽  
Calcium Ions ◽  
Total Concentration ◽  
Moisture Loss ◽  
Dynamic Mode ◽  
Scanning Calorimetry ◽  
Ionotropic Gelation ◽  
Complete Disintegration ◽  
Temperature Ranges

In this paper, the problem of studying of the films properties on the basis of uronate polysaccharides (sodium alginate and pectin low-esterified amidated), created on the principle of ionotropic gelation with the participation of calcium ions, has being considered. The purpose of the study is to determine the patterns of films formation based on the composition of the uronate polysaccharides, to determine their properties when heated and conditions of destruction or combustion. The thermophysical properties of the films in the temperature range 20–500°C were controlled by the method of differential scanning calorimetry in the dynamic mode. The temperature at which the loss of external and internal moisture is occurring have been determined. The temperatures when films are subjected to destruction have been founded. Thus, the mass loss of samples was noted in the following temperature ranges: 52–100°С and 40–100°С; the maximum moisture loss was noted at 83 and 85°C for specimens with a total concentration of uronate polysaccharides 2% and 3% respectively. Maximum external moisture losses were 6% and 9%; intra-linked moisture – 28.5 and 29% respectively. Complete disintegration of polymers occurs after 300 and 310°C for specimens with a total concentration of uronate polysaccharides 2% and 3% respectively. The investigation of the destraction temperatures of the above systems allows us to predict the principle of heat treatment of semi-finished products contained in films, created on the basis of the reaction of ionotropic gelation of polysaccharides and calcium ions.

scholarly journals Thermal Analysis of Whole Bacterial Cells Exposed to Potassium Permanganate Using Differential Scanning Calorimetry: a Biphasic Dose-Dependent Response to Stress

2009 ◽  
Vol 9 ◽  
pp. 109-117 ◽  
Author(s):  
Marina K. Abuladze ◽  
Victor M. Sokhadze ◽  
Emma N. Namchevadze ◽  
E. Kiziria ◽  
Leila V. Tabatadze ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Potassium Permanganate ◽  
Cell Level ◽  
Scanning Calorimetry ◽  
Whole Cell ◽  
Melting Heat ◽  
Response To Stress ◽  
The Impact ◽  
Arthrobacter Oxydans ◽  
Dose Dependent

Differential scanning calorimetry (DSC) was applied to estimate the impact of the toxic oxidant potassium permanganate (PM) on the intracellular structural and functional alterations at whole cell level using soil bacteriaArthrobacter oxydansas a model culture. Differential scanning calorimetry (DSC) was applied in order to estimate the impact of the toxic oxidant potassium permanganate (PM) on the intracellular structural and functional alterations at the whole cell level using the soil bacteria Arthrobacter oxydans as a model culture. We compared the total melting heat and the temperature of DNA-protein complex (DNP) melting at the PM application prior to the calorimetry measurement and after 24-h exposure at the concentration range 0.02–1.4 mM. The initial oxidative effect caused changes in the pattern of the whole cell melting spectra (mainly at the temperature range 56–78°C), the decrease of Tmax°C DNP melting, and did not influence significantly the total heat of bacterial melting at different concentrations of PM. The prolonged effect of permanganate up to 24 h was characterized by a biphasic dose-dependent response to stress estimated by the DSC technique and the colony-forming assay. The low doses of PM (0.02 and 0.2 mM) stimulated cell proliferation, and increased the total whole cell melting heat and the temperature of DNP melting. The toxic effect of PM up to 0.04 mMreduced cell viability, changed the character of multipeaked thermograms, and lowered the total melting heat and the temperature of DNP melting in a concentration-dependent manner. This study presents the DSC method for evaluating and monitoring the effects of exposure to potential human and environmental toxicants.

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