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

Milek, Igor; Črnigoj, Miha; Ulrih, Nataša Poklar; Kaletunç, Gönül

doi:10.1139/w07-069

Cited by 10 publications

(10 citation statements)

References 23 publications

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“…All of the events in the curves in Fig. 3 and in similar data in references [46][47][48][49][50] are endothermic, again showing the noncovalent bonds that structure cells are formed exothermically. Measurements of the heats of thermal denaturation of biopolymers too numerous to cite here all show that ΔH for thermal disruption of these structures is also endothermic.…”

Section: Temperature Scanning Calorimetrysupporting

confidence: 66%

Biological calorimetry and the thermodynamics of the origination and evolution of life

Hansen

Criddle

Battley

2009

Pure and Applied Chemistry

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Calorimetric measurements on biological systems from small molecules to whole organisms lead to a new conception of the nature of live matter that has profound consequences for our understanding of biology. The data show that the differences in Gibbs energy (ΔG) and enthalpy (ΔH) are near zero or negative and the difference in entropy (ΔS) is near zero between a random mixture of molecules and live matter of the same composition. A constant input of energy is required to maintain ion gradients, ATP production, and the other functions of living matter, but because cells are organized in a spontaneous process, no energy input is required to maintain the structure or organization of cells. Thus, the origin of life and evolution of complex life forms occurs by thermodynamically spontaneous processes, carbon-based life should be common throughout the universe, and because there is no energy cost, evolution can occur relatively rapidly.However, observations on biological systems challenge Schrödinger's model. Despite the assumed formidable energy and entropy costs, life did originate at least once, and possibly more than once [2]. Second, energy from catabolism is not transferred into new tissue during growth; catabolic reactions are used in driving (i.e., increasing the rates of) anabolic reactions but do not contribute to an overall higher-energy state in the anabolic products [2,3]. Third, live matter exists in a state of suspended animation or in a state with an extremely low rate of respiration for extended lengths of time without energy input (e.g., see [4][5][6][7]), for example, microorganisms, resurrection plants, seeds, spores, estivating animals, bdelloids, and inhabitants of desert ephemeral pools. Fourth, experimental data show that life does not always feed on negentropy [8]. And, evolutionary changes occur with frequencies that are difficult to envision if change to more complex life forms requires formation of ever-lower-entropy, higher-energy, metastable states.Explication of the reaction defining the thermodynamic system in which live matter is formed from nonliving matter resolves the apparent inconsistencies between Schrödinger's model for live matter and these observations. Schrödinger [1] did not explicitly define the reaction used to conclude that the entropy of live matter is lower than that of the "foodstuffs" from which it was formed. The product is clearly living cells, tissues, or an organism, but the state of the live matter and what is meant by "foodstuffs", i.e., the reactants, are not clear. Is the live matter an animal in motion or is it an embryo in a seed in a state of suspended animation? In autotrophs, "foodstuffs" could mean CO 2 , H 2 O, and N 2 , or it could mean the substrates for respiration such as carbohydrates and amino acids. Whether living tissues are in a high-or a low-energy state is relative to the reactants and thus depends on the system considered.Comparison of a random mixture of molecules in aqueous solution and live matter of the same composition is the appropriate...

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Section: Temperature Scanning Calorimetrysupporting

confidence: 66%

Biological calorimetry and the thermodynamics of the origination and evolution of life

Hansen

Criddle

Battley

2009

Pure and Applied Chemistry

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“…In the context of radiobiology, "survival" means the conservation of the cell's proliferative capacity [19] (see definitions box). Regarding HT, there is considerable literature describing the impact of heat on different cellular components [20][21][22][23][24], and several models are aimed to predict the survival of cells under HT treatments [25]. For thermal-radiosensitisation using temperatures of 40-46 • C, there is a general agreement on a relevant role of DNA repair impairment by heat-induced protein denaturation in the processes of radiosensitisation between 40-46 • C [9-11, 17, 21, 22, 26].…”

Section: Introductionmentioning

confidence: 99%

Mathematical model for the thermal enhancement of radiation response: Thermodynamic approach

Mendoza¹,

Michlíková²,

Berger³

et al. 2020

Preprint

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Radiotherapy can effectively kill malignant cells, but the doses required to cure cancer patients can often not be applied as they come at the cost of severe collateral damage to adjacent healthy tissues. Hyperthermia (HT) is a promising option to improve the outcome of radiation treatment (RT) and is increasingly applied in the clinics by incorporating a broad range of technological advances over the past 15 years. However, the design of adequate HT treatment scheduling in the clinical setting has remained challenging. From the theoretical perspective, mathematical models to predict the proposed synergistic effect and therapeutic outcome of combined treatment schemes are essential to improving treatment outcomes. We here propose a theoretical model to better understand the thermal enhancement of RT. In our model, the thermal enhancement ratio (TER) is explained by the fraction of cells that is radiosensitised by the infliction of sublethal damage through mild HT. In the course of further damage, the cells finally lose proliferative capacity and die, respectively, in a non-reversible process. We suggest the TER to be proportional to the energy invested in the sensitisation, which is modelled as a simple rate process. Assuming protein denaturation as the main driver of HT-induced sublethal damage and considering the temperature dependence of the heat capacity of cellular proteins, the sensitisation rates were found to depend exponentially on temperature; this is in agreement with previous empirical observations. Accordingly, our theoretical calculations well reproduce experimental data from both in-vitro and in-vivo studies for the simultaneous application of mild HT and RT. Our model is able to predict and explain the thermal modulation of cellular radioresponse. Ongoing systematic experimental studies, and calorimetry measurements, shall further validate our predictions for other cell models.

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“…Whole cell differential scanning calorimetry (DSC) has been used to characterize the thermal stability of cell components in bacterial cells ( Miles, Mackey & Parsons, 1986 ; Mackey et al, 1988 ; Lepock, Frey & Inniss, 1990 ; Anderson et al, 1991 ; Anderson et al, 1991? ; Mackey et al, 1991 ; Mackey et al, 1993 ; Teixeira et al, 1997 ; Mohácsi-Farkas et al, 1999 ; Bayles et al, 2000 ; Lee & Kaletunc, 2002a ; Lee & Kaletunc, 2002b ; Alpas et al, 2003 ; Kaletunc et al, 2004 ; Lepock, 2005 ; Nguyen, Corry & Miles, 2006 ; Tunick, Bayles & Novak, 2006 ; Abuladze et al, 2009 ; Lee & Kaletunç, 2010 ), archaeal cells ( Milek et al, 2007 ), endospores ( Belliveau et al, 1992 ), and eukaryotic cells ( Lepock et al, 1990 ; Obuchi et al, 2000 ). DSC has also been used to probe the mechanisms of numerous AMPs in model membrane systems, including the cathelicidins ( Andrushchenko, Vogel & Prenner, 2007 ), LL-37 ( Sevcsik et al, 2007 ), β -17 ( Epand et al, 2003 ), and MSI-78 ( Hallock, Lee & Ramamoorthy, 2003 ; Ramamoorthy et al, 2006 ).…”

Section: Introductionmentioning

confidence: 99%

Differential scanning calorimetry of wholeEscherichia colitreated with the antimicrobial peptide MSI-78 indicate a multi-hit mechanism with ribosomes as a novel target

Brannan

Whelan

Cole

et al. 2015

PeerJ

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Differential Scanning Calorimetry (DSC) of intact Escherichia coli (E. coli) was used to identify non-lipidic targets of the antimicrobial peptide (AMP) MSI-78. The DSC thermograms revealed that, in addition to its known lytic properties, MSI-78 also has a striking effect on ribosomes. MSI-78’s effect on DSC scans of bacteria was similar to that of kanamycin, an antibiotic drug known to target the 30S small ribosomal subunit. An in vitro transcription/translation assay helped confirm MSI-78’s targeting of ribosomes. The scrambled version of MSI-78 also affected the ribosome peak of the DSC scans, but required greater amounts of peptide to cause a similar effect to the unscrambled peptide. Furthermore, the effect of the scrambled peptide was not specific to the ribosomes; other regions of the DSC thermogram were also affected. These results suggest that MSI-78’s effects on E. coli are at least somewhat dependent on its particular structural features, rather than a sole function of its overall charge and hydrophobicity. When considered along with earlier work detailing MSI-78’s membrane lytic properties, it appears that MSI-78 operates via a multi-hit mechanism with multiple targets.

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

Cited by 10 publications

References 23 publications

Biological calorimetry and the thermodynamics of the origination and evolution of life

Biological calorimetry and the thermodynamics of the origination and evolution of life

Mathematical model for the thermal enhancement of radiation response: Thermodynamic approach

Differential scanning calorimetry of wholeEscherichia colitreated with the antimicrobial peptide MSI-78 indicate a multi-hit mechanism with ribosomes as a novel target

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