Magnetic nanofibrous scaffolds of poly(caprolactone) (PCL) incorporating magnetic nanoparticles (MNP) were produced, and their effects on physico-chemical, mechanical and biological properties were ...extensively addressed to find efficacy for bone regeneration purpose. MNPs 12 nm in diameter were citrated and evenly distributed in PCL solutions up to 20% and then were electrospun into nonwoven nanofibrous webs. Incorporation of MNPs greatly improved the hydrophilicity of the nanofibers. Tensile mechanical properties of the nanofibers (tensile strength, yield strength, elastic modulus and elongation) were significantly enhanced with the addition of MNPs up to 15%. In particular, the tensile strength increase was as high as ∼25 MPa at 15% MNPs vs. ∼10 MPa in pure PCL. PCL-MNP nanofibers exhibited magnetic behaviors, with a high saturation point and hysteresis loop area, which increased gradually with MNP content. The incorporation of MNPs substantially increased the degradation of the nanofibers, with a weight loss of ∼20% in pure PCL, ∼45% in 10% MNPs and ∼60% in 20% MNPs. Apatite forming ability of the nanofibers tested in vitro in simulated body fluid confirmed the substantial improvement gained by the addition of MNPs. Osteoblastic cells favored the MNPs-incorporated nanofibers with significantly improved initial cell adhesion and subsequent penetration through the nanofibers, compared to pure PCL. Alkaline phosphatase activity and expression of genes associated with bone (collagen I, osteopontin and bone sialoprotein) were significantly up-regulated in cells cultured on PCL-MNP nanofibers than those on pure PCL. PCL-MNP nanofibers subcutaneously implanted in rats exhibited minimal adverse tissue reactions, while inducing substantial neoblood vessel formation, which however, greatly limited in pure PCL. In vivo study in radial segmental defects also signified the bone regeneration ability of the PCL-MNP nanofibrous scaffolds. The magnetic, bone-bioactive, mechanical, cellular and tissue attributes of MNP-incorporated PCL nanofibers make them promising candidate scaffolds for bone regeneration.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Summary
Germination requires sufficient water absorption by seeds, but excessive water in the soil inhibits plant growth. We therefore hypothesized that tolerance mechanisms exist that help young ...seedlings survive and develop in waterlogged conditions.
Many ATP‐BINDING CASSETTE TRANSPORTER subfamily G (ABCG) proteins protect terrestrial plants from harsh environmental conditions. To establish whether any of these proteins facilitate plant development under waterlogged conditions, we observed the early seedling growth of many ABCG transporter mutants under waterlogged conditions.
abcg5 seedlings exhibited severe developmental problems under waterlogged conditions: the shoot apical meristem was small, and the seedling failed to develop true leaves. The seedlings had a high water content and reduced buoyancy on water, suggesting that they were unable to retain air spaces on and inside the plant. Supporting this possibility, abcg5 cotyledons had increased cuticle permeability, reduced cuticular wax contents, and a much less dense cuticle layer than the wild‐type.
These results indicate that proper development of plants under waterlogged conditions requires the dense cuticle layer formed by ABCG5 activity.
See also the Editorial on this article by Sasidharan et al., 229: 5–7.
Photosynthesis is the process by which plants harvest sunlight to produce sugars from carbon dioxide and water. It is the primary source of energy for all life on Earth; hence it is important to ...understand how this process responds to climate change and human impact. However, model-based estimates of gross primary production (GPP, output from photosynthesis) are highly uncertain, in particular over heavily managed agricultural areas. Recent advances in spectroscopy enable the space-based monitoring of sun-induced chlorophyll fluorescence (SIF) from terrestrial plants. Here we demonstrate that spaceborne SIF retrievals provide a direct measure of the GPP of cropland and grassland ecosystems. Such a strong link with crop photosynthesis is not evident for traditional remotely sensed vegetation indices, nor for more complex carbon cycle models. We use SIF observations to provide a global perspective on agricultural productivity. Our SIF-based crop GPP estimates are 50-75% higher than results from state-of-the-art carbon cycle models over, for example, the US Corn Belt and the Indo-Gangetic Plain, implying that current models severely underestimate the role of management. Our results indicate that SIF data can help us improve our global models for more accurate projections of agricultural productivity and climate impact on crop yields. Extension of our approach to other ecosystems, along with increased observational capabilities for SIF in the near future, holds the prospect of reducing uncertainties in the modeling of the current and future carbon cycle.
In hemodialysis patients, fluid overload and malnutrition are accompanied by extracellular fluid (ECF) expansion and intracellular fluid (ICF) depletion, respectively. We investigated the ...relationship between ECF/ICF ratio (as an integrated marker reflecting both fluid overload and malnutrition) and survival and cardiovascular disease (CVD) in the context of malnutrition-inflammation-arteriosclerosis (MIA) complex.
Seventy-seven patients from a single hemodialysis unit were prospectively enrolled. The ECF/ICF volume was measured by segmental multi-frequency bioimpedance analysis. MIA and volume status were measured by serum albumin, C-reactive protein (CRP), pulse wave velocity (PWV) and plasma B-type natriuretic peptide (BNP), respectively.
The mean ECF/ICF ratio was 0.56±0.06 and the cut-off value for maximum discrimination of survival was 0.57. Compared with the low ECF/ICF group, the high ECF/ICF group (ratio≥0.57, 42%) had higher all-cause mortality, CVD, CRP, PWV, and BNP, but lower serum albumin. During the 5-year follow-up, 24 all-cause mortality and 38 CVD occurred (18 and 24, respectively, in the high ECF/ICF group versus 6 and 14 respectively in the low ECF/ICF group, P<0.001). In the adjusted Cox analysis, the ECF/ICF ratio nullifies the effects of the MIA and volume status on survival and CVD and was an independent predictor of all-cause mortality and CVD: hazard ratio (95% confidence interval); 1.12 (1.01-1.25) and 1.09 (1.01-1.18) for a 0.01 increase in the ECF/ICF ratio. The degree of malnutrition (albumin), inflammation (CRP), arteriosclerosis (PWV), and fluid overload (BNP) were correlated well with the ECF/ICF ratio.
Hemodialysis patients with high ECF/ICF ratio are not only fluid overloaded, but malnourished and have stiff artery with more inflammation. The ECF/ICF ratio is highly related to the MIA complex, and is a major risk indicator for all-cause mortality and CVD.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Endothelial dysfunction is one of the main age‐related arterial phenotypes responsible for cardiovascular disease (CVD) in older adults. This endothelial dysfunction results from decreased ...bioavailability of nitric oxide (NO) arising downstream of endothelial oxidative stress. In this study, we investigated the protective effect of anthocyanins and the underlying mechanism in rat thoracic aorta and human vascular endothelial cells in aging models. In vitro, cyanidin‐3‐rutinoside (C‐3‐R) and cyanidin‐3‐glucoside (C‐3‐G) inhibited the d‐galactose (d‐gal)‐induced senescence in human endothelial cells, as indicated by reduced senescence‐associated‐β‐galactosidase activity, p21, and p16INK4a. Anthocyanins blocked d‐gal‐induced reactive oxygen species (ROS) formation and NADPH oxidase activity. Anthocyanins reversed d‐gal‐mediated inhibition of endothelial nitric oxide synthase (eNOS) serine phosphorylation and SIRT1 expression, recovering NO level in endothelial cells. Also, SIRT1‐mediated eNOS deacetylation was shown to be involved in anthocyanin‐enhanced eNOS activity. In vivo, anthocyanin‐rich mulberry extract was administered to aging rats for 8 weeks. In vivo, mulberry extract alleviated endothelial senescence and oxidative stress in the aorta of aging rats. Consistently, mulberry extract also raised serum NO levels, increased phosphorylation of eNOS, increased SIRT1 expression, and reduced nitrotyrosine in aortas. The eNOS acetylation was higher in the aging group and was restored by mulberry extract treatment. Similarly, SIRT1 level associated with eNOS decreased in the aging group and was restored in aging plus mulberry group. These findings indicate that anthocyanins protect against endothelial senescence through enhanced NO bioavailability by regulating ROS formation and reducing eNOS uncoupling.
Aging is known for its correlation with increased protein acetylation rates and the decline of sirtuin‐1 (SIRT1) deacetylation activity. This study demonstrated that anthocyanin‐rich mulberry extract reduces oxidative stress in aging vasculature and attenuates endothelial dysfunction through reversed inhibition of endothelial nitric oxide synthase (eNOS), serine phosphorylation, and SIRT1 expression, recovering NO level in senescence.
The radial microstructure development of polyacrylonitrile-based carbon fibers is traced during continuous carbonization from 400 to 1400 °C. Based on the changes in the microstructure and mechanical ...properties of the fibers, it is confirmed that they undergo four distinctive stages depending on the temperature: (1) further cyclization in a remained unstabilized structure (400–600 °C), (2) crosslinking by dehydrogenation (600–800 °C), (3) crosslinking by denitrogenation (1000–1200 °C), and (4) development of turbostratic structure (1200–1400 °C). A structural analysis of the surface, skin, and core regions reveals that the innermost structure (core) originates from a high degree of structural relaxation. In contrast, densification is dominated in the outermost structure (surface). Such a radial heterogeneity is attributed to gas evolution along the radial direction of the fibers during the high-temperature carbonization and fiber shrinkage. The tensile strength exhibits a strong relationship with the crystal sizes as compared to the degree of disorder and amorphous structures, indicating that the crystal growth by densification has a greater influence on the tensile properties than the structure relaxation.
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MXenes with a two-dimensional (2D) structure have attracted attention as potential biomedical materials. In this study, Ti3C2 MXene particles with 2D-lamellar structures were intercalated and their ...potential as a biomaterial was evaluated using human mesenchymal stem cells. Intercalated MXene was characterized in terms of microstructure, phase composition, and size. Cell proliferation experiments with MXene particles confirmed that concentrations >50 μg/mL were cytotoxic, while concentrations <20 μg/mL promoted osteogenic differentiation. Moreover, MXene effectively facilitated the early and late osteogenic gene expression.
Abstract
Protecting replication fork integrity during DNA replication is essential for maintaining genome stability. Here, we report that SDE2, a PCNA-associated protein, plays a key role in ...maintaining active replication and counteracting replication stress by regulating the replication fork protection complex (FPC). SDE2 directly interacts with the FPC component TIMELESS (TIM) and enhances its stability, thereby aiding TIM localization to replication forks and the coordination of replisome progression. Like TIM deficiency, knockdown of SDE2 leads to impaired fork progression and stalled fork recovery, along with a failure to activate CHK1 phosphorylation. Moreover, loss of SDE2 or TIM results in an excessive MRE11-dependent degradation of reversed forks. Together, our study uncovers an essential role for SDE2 in maintaining genomic integrity by stabilizing the FPC and describes a new role for TIM in protecting stalled replication forks. We propose that TIM-mediated fork protection may represent a way to cooperate with BRCA-dependent fork stabilization.
Cytochrome P450s (CYPs), heme-containing monooxygenases, play important roles in a wide variety of metabolic processes important for development as well as biotic/trophic interactions in most living ...organisms. Functions of some CYP enzymes are similar across organisms, but some are organism-specific; they are involved in the biosynthesis of structural components, signaling networks, secondary metabolisms, and xenobiotic/drug detoxification. Fungi possess more diverse CYP families than plants, animals, or bacteria. Various fungal CYPs are involved in not only ergosterol synthesis and virulence but also in the production of a wide array of secondary metabolites, which exert toxic effects on humans and other animals. Although few studies have investigated the functions of fungal CYPs, a recent systematic functional analysis of CYP genes in the plant pathogen
identified several novel CYPs specifically involved in virulence, asexual and sexual development, and degradation of xenobiotics. This review provides fundamental information on fungal CYPs and a new platform for further metabolomic and biochemical studies of CYPs in toxigenic fungi.
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