| 1. |
- Klionsky, Daniel J., et al.
(author)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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In: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Research review (peer-reviewed)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 2. |
- Chen, Shu-Feng, et al.
(author)
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Multireference theoretical studies on the solvent effect of firefly multicolor bioluminescence
- 2011
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In: International Journal of Quantum Chemistry. - : Wiley. - 0020-7608 .- 1097-461X. ; 111:13, s. 3371-3377
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Journal article (peer-reviewed)abstract
- In concert with the recent spectroscopic studies of the light-color modulation mechanism of firefly (Hirano et al., J Am Chem Soc 2009, 131, 2385), quantum chemical calculations using complete active space SCF (CASSCF), multistate complete active space second order perturbation (MS-CASPT2) theory as well as a time-dependent density functional theory (TD-DFT) approach with the Coulomb attenuated hybrid exchange-correlation functional (CAM-B3LYP) were performed on the excited state (S1) of the keto-form oxyluciferin (keto-OxyLH2). Benzene, DMSO, CH3CN, and H2O were chosen as polar solvents. The polarization effect of less polar solvent was considered by a simple model, complex of keto-OxyLH2, and NH3 with different covalent character. The calculated results supported the experimental conclusion: (1) the light emitter of bioluminescence is the S1 state of keto-OxyLH2 anion [(keto-1)*], and (2) light emission from (keto-1)* is modulated by the polarity of surrounding environment and the degree of covalent character of hydrogen bond between (keto-1)* and a protonated basic moiety. The mechanism of the multicolor bioluminescence was discussed from the theoretical viewpoint.
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| 3. |
- Navizet, Isabelle, et al.
(author)
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Are the Bio- and Chemiluminescence States of the Firefly Oxyluciferin the Same as the Fluorescence State?
- 2013
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In: Photochemistry and Photobiology. - : Wiley. - 0031-8655 .- 1751-1097. ; 89:2, s. 319-325
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Journal article (peer-reviewed)abstract
- A usual strategy in both experimental and theoretical studies on bio- and chemiluminescence is to analyze the fluorescent properties of the bio- and chemiluminescence reaction product. Recent findings in a coelenteramide and Cypridina oxyluciferin model arise a concern on the validity of this procedure, showing that the light emitters in each of these luminescent processes might differ. Here, the thermal decomposition path of the firefly dioxetanone and the light emission states of the Firefly oxyluciferin responsible for the bio-, chemiluminescence, and fluorescence of the molecule are characterized using ab initio quantum chemistry and hybrid quantum chemistry/molecular mechanics methods to determine if the scenario found in the coelenteramide and Cypridina oxyluciferin study does also apply to the Firefly bioluminescent systems. The results point out to a unique emission state in the bio-, chemiluminescence, and fluorescence phenomena of the Firefly oxyluciferin and, therefore, using fluorescence properties of this system is reasonable.
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| 4. |
- Yue, Ling, et al.
(author)
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Can the Closed-Shell DFT Methods Describe the Thermolysis of 1,2-Dioxetanone?
- 2012
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In: Journal of Chemical Theory and Computation. - : American Chemical Society (ACS). - 1549-9618 .- 1549-9626. ; 8:11, s. 4359-4363
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Journal article (peer-reviewed)abstract
- The chemiluminescent decomposition of 1,2-dioxetanone has in the past been studied by state-of-the-art multireference quantum chemical calculations, and a stepwise biradical mechanism was established. Recently, this decomposition has been reinvestigated, and a concerted mechanism has been proposed based on calculations performed at the closed-shell density functional theory (DFT) level of theory. In order to solve this apparent mechanistic contradiction, the present paper presents restricted and unrestricted DFT results obtained using functionals including different amounts of Hartree–Fock (HF) exchange, repeating and complementing the above-mentioned DFT calculations. The calculated results clearly indicate that the closed-shell DFT methods cannot correctly describe the thermolysis of 1,2-dioxetanone. It is found that unrestricted Kohn–Sham reaction energies and barriers are always lower than the ones obtained using a restricted formalism. Hence, from energy principles, the biradical mechanism is found to be prevailing in the understanding of the 1,2-dioxetanone thermolysis.
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| 5. |
- Zang, Xiao-Ying, et al.
(author)
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Pivotal factors interfering in 24-hour blood pressure fluctuation and arterial stiffness in a community of Chinese elderly hypertensive patients
- 2013
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In: Journal of Clinical Nursing. - : Wiley. - 0962-1067 .- 1365-2702. ; 22:3/4, s. 379-388
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Journal article (peer-reviewed)abstract
- Aims and objectives: To explore which sociodemographic and clinical factors could interfere in the parameters of ambulatory blood pressure monitoring and determine the affecting factors of Ambulatory Arterial Stiffness Index.Background: Although the clinical relevance of ambulatory blood pressure monitoring and Ambulatory Arterial Stiffness Index have been studied, the explanation of their role and related interfering factors remains controversial in patients with different disease or age, etc.Design: Cross-sectional study.Methods: The study was carried out between October 2008–October 2009. A convenience sample of hypertensive patients over 60 years old was recruited in China. Twenty-four hour ambulatory blood pressure monitoring was carried out on the non-dominant arm using an oscillometric device.Results: (1) All 95 patients completed the study and their ages ranged from 60–76 years. (2) There were statistical differences for certain parameters of ambulatory blood pressure monitoring between different characteristics of patients. Financial status was an important factor interfering in patients’ BP fluctuation, especially daytime and 24 hours systolic pressure. The higher body mass index the patients had, the higher the pressure was. (3) Multiple variants logistic analysis of Ambulatory Arterial Stiffness Index showed statistical differences only in coefficient variation of 24-hour diastolic pressure and daytime systolic blood pressure.Conclusions: There are more factors that interfered with systolic pressure and diastolic pressure during the day than nigh. Patients who have less nocturnal dipping may have a higher night time systolic pressure and diastolic pressure. The coefficient of variation of 24 hours diastolic pressure and daytime systolic pressure contribute more to Ambulatory Arterial Stiffness Index which should arouse practitioners’ attention.Relevance to clinical practice: Ambulatory blood pressure monitoring should be used as a routine procedure, as well as Ambulatory Arterial Stiffness Index calculated for older hypertensive patients. The findings may be used to guide community health providers to pay more attention to the factors that may influence BP fluctuation and Ambulatory Arterial Stiffness Index according to individual’s characteristics.
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