We attempt quantitative implementation of a previous suggestion that asymmetric charge neutralization of DNA phosphate groups may provide part of the driving force for nucleosome folding. Polyelectrolyte theory can be used to estimate the effective compressive force acting along the length of one side of the DNA surface when a fraction of the phosphate groups are neutralized by histones bound to that side. A standard engineering formula then relates the force to the bending amplitude caused by it. Calculated bending amplitudes are consistent with the curvature of nucleosomal DNA and the overall extent of charge neutralization by the histones. The relation of the model to various aspects of nucleosome folding, including the detailed path of core-particle DNA, is discussed. Several other DNA-protein complexes are listed as examples of possible asymmetric charge-induced bending.
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http://dx.doi.org/10.1080/07391102.1989.10506519 | DOI Listing |
Front Nutr
January 2025
Department of Ophthalmology, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, China.
Aim: This study aimed to explore the association between the ratio of 4-pyridoxine (4-PA) to pyridoxal 5'-phosphate (PLP) (4-PA/PLP) and diabetic retinopathy (DR) and further assess the mediating effect of Endothelial Activation and Stress Index (EASIX) on the association between 4-PA/PLP and DR.
Methods: In this cross-sectional study, 1,698 patients with diabetes from the National Health and Nutrition Examination Survey were included. According to the median, 4-PA/PLP was categorized into a high-level group (≥0.
Int J Biomater
January 2025
Iranian Center for Endodontic Research, Research Institute for Dental Sciences, Shahid Beheshti University of Medical Sciences, Tehran 1983963113, Iran.
This study aimed to evaluate the impact of different manipulation methods and storage environments on the microstructural, chemical, and mechanical properties of calcium-enriched mixture (CEM) cement. Four sample groups were examined, including nondried (ND-I) and dried (D-I) groups placed directly in an incubator, dried samples stored in phosphate-buffered saline (PBS) (D-P), and dried samples stored in distilled water (D-W). Various analyses, including Vickers microhardness, compressive strength, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) were conducted after incubating the samples for 7 days.
View Article and Find Full Text PDFNephrol Dial Transplant
January 2025
Department of Microbiology, Immunology and Transplantation; Nephrology and Renal Transplantation Research Group, KU Leuven, Leuven, Belgium.
Vitamin D deficiency is common in patients with chronic kidney disease (CKD) and associates with poor outcomes. Current clinical practice guidelines recommend supplementation with nutritional vitamin D as for the general population. However, recent large-scale, clinical trials in the general population failed to demonstrate a benefit of vitamin D supplementation on skeletal or non-skeletal outcomes, fueling a debate on the rationale for screening for and correcting vitamin D deficiency, both in non-CKD and CKD populations.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
College of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071, PR China. Electronic address:
The synthesis of highly efficient and environmentally friendly flame retardants through the synergistic interaction of boron, phosphorus and nitrogen is becoming a new research direction. In this study, N-DBSPA, a flame retardant with high flame retardancy, high thermal stability and high efficiency, was prepared by the reaction between pentaerythritol borate and amino trimethylene phosphate, and the limiting oxygen index (LOI) of the modified cotton fabric increased from 18 % to 44.7 % at a weight gain (WG) of 20.
View Article and Find Full Text PDFPlant Dis
January 2025
Henan Normal University, College of Life Sciences, Xinxiang, Xinxiang, Henan, China, 453007.
Echinacea purpurea (Eastern Purple Coneflower) is a perennial herbaceous plant belonging to the Asteraceae. It originated from North America and is cultivated all over the world. Extracts of E.
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