•In laboratory setting, 10ppb nanoplastics (25nm) can alter the DOM-POM transition in seawater samples.•Hydrophobic interactions contribute to the facilitation of NP-DOM assembly.•Results suggest ...that casual disposal of plastic waste potentially poses unforeseen disturbance to the marine carbon-cycle.
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The environmental impact of nanoplastics (NPs) released into natural aquatic surroundings is an increasing concern. NPs are widely generated from our daily waste disposal and eventually reach the ocean, wherein consequent influences on aquatic environments remain unclear. In this regard, there are few studies investigating NP-related ecological impacts. Comprising one of Earth's major carbon pools, marine dissolved organic matter (DOM) serves an essential role in global carbon dynamics. The spontaneous assembly of DOM into particulate organic matter (POM) plays important roles in the marine carbon cycle, and is involved in hemostasis of various ecological communities. Here, we report that 10 ppb NPs (polystyrene/polymethyl methacrylate, 25 nm) appeared in a water column accelerate the kinetic assembly rate of DOM-POM transition. NPs with various characteristics show similar influences on DOM assembly, and seawater samples collected from disparate sites were used to further confirm this unanticipated phenomenon. In this study, we demonstrated that hydrophobic interactions contribute to the facilitation of NP-DOM aggregations. Our results illustrate that NPs alter DOM-POM assembly, which may potentiate unanticipated perturbation to the largest marine carbon pool. Such effects would warrant increased vigilance on current practices of plastic usage and disposal.
Corylin is a main compound isolated from Psoralea corylifolia L. (Fabaceae). A variety of pharmacological effects such as antioxidant, anti-proliferation, and anti-inflammatory properties of corylin ...have been reported. Nevertheless, the effect of corylin in microbial infection and sepsis remains unclear. In the present study, we investigated the anti-inflammatory effects of corylin. Our experimental results demonstrated that corylin inhibited the production of TNF-α, IL-6 and NO by both LPS-activated RAW 264.7 cells and LPS-activated murine peritoneal macrophages. Moreover, corylin suppressed the expression levels of iNOS and COX-2, reduced the production of PGE
and HMGB1, blocked the translocation of HMGB1 from the nucleus to cytosol, and decreased the phosphorylation of MAPKs in LPS-activated RAW 264.7 cells as well as suppressed the activity of NF-κB in LPS-activated J-Blue cells. In addition, the administration of corylin reduced the production of NO and TNF-α, decreased LPS-induced liver damage markers (AST and ALT) and kidney damage markers (BUN and CRE), attenuated infiltration of inflammatory cells and tissue damage of lung, liver and kidney, and enhanced the survival rate of LPS-challenged mice. Taken together, these results show the anti-inflammatory properties of corylin on LPS-induced inflammation and sepsis. Corylin could potentially be a novel anti-inflammatory and immunosuppressive drug candidate in the treatment of sepsis and septic shock.
The substantial increase in plastic pollution in marine ecosystems raises concerns about its adverse impacts on the microbial community. Microorganisms (bacteria, phytoplankton) are important ...producers of exopolymeric substances (EPS), which govern the processes of marine organic aggregate formation, microbial colonization, and pollutant mobility. Until now, the effects of nano- and micro-plastics on characteristics of EPS composition have received little attention. This study investigated EPS secretion by four phytoplankton species following exposure to various concentrations of polystyrene nano- and microplastics (55 nm nanoparticles; 1 and 6 μm microparticles). The 55 nm nanoparticles induced less growth/survival (determined on a DNA basis) and produced EPS with higher protein-to-carbohydrate (P/C) ratios than the exposure to microplastic particles. The amount of DNA from the four marine phytoplankton showed a higher negative linear correlation with increasing P/C ratios, especially in response to nanoplastic exposure. These results provide evidence that marine phytoplankton are quite sensitive to smaller-sized plastics and actively modify their EPS chemical composition to cope with the stress from pollution. Furthermore, the release of protein-rich EPS was found to facilitate aggregate formation and surface modification of plastic particles, thereby affecting their fate and colonization. Overall, this work offers new insights into the potential harm of different-sized plastic particles and a better understanding of the responding mechanism of marine phytoplankton for plastic pollution. The data also provide needed information about the fate of marine plastics and biogenic aggregation and scavenging processes.
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•High levels of nano-/micro-plastics can decrease the survival of phytoplankton.•High concentrations of nano-/micro-plastics can trigger protein-rich EPS release.•A negative correlation between cell survival and P/C ratio was established.•Protein-rich EPS can facilitate the aggregate formation.
Adherens junctions (AJs) play a fundamental role in tissue integrity; however, the organization and dynamics of the key AJ transmembrane protein, E-cadherin, both inside and outside of AJs, remain ...controversial. Here we have studied the distribution and motility of E-cadherin in punctate AJs (pAJs) of A431 cells. Using single-molecule localization microscopy, we show that pAJs in these cells reach more than 1 μm in length and consist of several cadherin clusters with crystal-like density interspersed within sparser cadherin regions. Notably, extrajunctional cadherin appears to be monomeric, and its density is almost four orders of magnitude less than observed in the pAJ regions. Two alternative strategies of tracking cadherin motion within individual junctions show that pAJs undergo actin-dependent rapid—on the order of seconds—internal reorganizations, during which dense clusters disassemble and their cadherins are immediately reused for new clusters. Our results thus modify the classical view of AJs by depicting them as mosaics of cadherin clusters, the short lifetimes of which enable stable overall morphology combined with rapid internal rearrangements.
Organic particle dynamics in the surface ocean plays a critical part in the marine carbon cycle. Aggregation of marine organic particles drives their downward transport to support various marine ...organisms on their transit to the sediments. Extracellular polymeric substances (EPS) from various microbes are a major contributor to the oceanic organic particle pool. The stickiness of EPS is expected to play a determining role in the aggregation process of particles; however, stickiness parameters are usually indirectly estimated through data fitting without direct assessment. Here a magnetic tweezer method was developed to quantitatively assess the stickiness of three model EPS produced by: Amphora sp., (diatom), Emiliania huxleyi (coccolithophore), and Sagittula stellata (bacteria), under different in vitro environmental conditions (salinity or EDTA complexed cations) and surface matrices (EPS-EPS and bare glass). Our results showed the stickiness of three microbial EPS decreasing for S. stellata > E. huxleyi > Amphora sp., in line with their decreasing protein-to-carbohydrate (P/C) ratios (related to their relative hydrophobicity). The data not only emphasize the importance of hydrophobicity on EPS stickiness, but also demonstrates that salinity and the nature of the substrate surface can influence the stickiness. Furthermore, we investigated stickiness between various types of EPS, and the observed selective stickiness of EPS between species may shed light on the interactions among heterogeneous marine microorganisms. Overall, this newly developed system provides a platform to assess the EPS stickiness to advance our understanding of the aggregation and sedimentation process of organic particles that are critical for the fate of organic carbon as well as for biofilm formation and microbial colonization of surfaces in the ocean.
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•A magnetic tweezer-based system was developed to assess the stickiness of EPS.•EPS stickiness is closely related to protein/carbohydrate ratio.•Ca2+ crosslinking and hydrophobic interactions contribute to EPS stickiness.
The behavior and toxicity of silver engineered nanoparticles (Ag-ENs) to the mixotrophic freshwater alga Ochromonas danica were examined in the present study to determine whether any other mechanisms ...are involved in their algal toxicity besides Ag(+) liberation outside the cells. Despite their good dispersability, the Ag-ENs were found to continuously aggregate and dissolve rapidly. When the initial nanoparticle concentration was lower than 10 µM, the total dissolved Ag(+) concentration (Ag(+)(T)) in the suspending media reached its maximum after 1 d and then decreased suggesting that Ag(+) release might be limited by the nanoparticle surface area under these conditions. Furthermore, Ag-EN dissolution extent remarkably increased in the presence of glutathione. In the Ag-EN toxicity experiment, glutathione was also used to eliminate the indirect effects of Ag(+) that was released. However, remarkable toxicity was still observed although the free Ag(+) concentration in the media was orders of magnitude lower than the non-observed effect concentration of Ag(+) itself. Such inhibitive effects were mitigated when more glutathione was added, but could never be completely eliminated. Most importantly, we demonstrate, for the first time, that Ag-ENs can be taken in and accumulated inside the algal cells, where they exerted their toxic effects. Therefore, nanoparticle internalization may be an alternative pathway through which algal growth can be influenced.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In order to assess the overall risk posed by engineered nanoparticles (ENPs), the biological effects of this emergent pollutant to aquatic ecosystems must be evaluated. We present findings from ...studies conducted with a diversity of ENPs (metallic, quantum dots) on a variety of freshwater and marine algae (phytoplankton) illustrating both their direct and indirect effects. We show that in general, while the surface properties of ENPs govern their aggregation behavior and ionic strength controls their dissolution, exopolymeric substances (EPS) produced by algae determine their potential to be toxic and thereby movement through the water column and food web. The production of EPS reduces the impact of ENPs (bioavailability and toxicity) and/or their ions on cellular activities of algae. It does not however directly reduce the aggregation and/or solubility of ENPs but rather affects their stability. Complicating understanding of these interactions is the great assortment of surface coatings for ENPs. This perspective is intended to highlight our current knowledge and the need for future research particularly focused on determining the fate and transport of ENPs in the aquatic environment.
With a median survival time of 15 months, glioblastoma multiforme is one of the most aggressive primary brain cancers. The crucial roles played by the extracellular matrix (ECM) stiffness in glioma ...progression and treatment resistance have been reported in numerous studies. However, the association between ECM-stiffness-regulated genes and the prognosis of glioma patients remains to be explored. Thus, using bioinformatics analysis, we first identified 180 stiffness-dependent genes from an RNA-Seq dataset, and then evaluated their prognosis in The Cancer Genome Atlas (TCGA) glioma dataset. Our results showed that 11 stiffness-dependent genes common between low- and high-grade gliomas were prognostic. After validation using the Chinese Glioma Genome Atlas (CGGA) database, we further identified four stiffness-dependent prognostic genes: FN1, ITGA5, OSMR, and NGFR. In addition to high-grade glioma, overexpression of the four-gene signature also showed poor prognosis in low-grade glioma patients. Moreover, our analysis confirmed that the expression levels of stiffness-dependent prognostic genes in high-grade glioma were significantly higher than in low-grade glioma, suggesting that these genes were associated with glioma progression. Based on a pathophysiology-inspired approach, our findings illuminate the link between ECM stiffness and the prognosis of glioma patients and suggest a signature of four stiffness-dependent genes as potential therapeutic targets.
Patients with subdural hemorrhage (SDH) and a Glasgow Coma Scale (GCS) score of 13–15 are typically categorized as having mild traumatic brain injury. We hypothesize that patients without a maximum ...GCS score – specifically, patients with GCS scores of 13 and 14 – may exhibit poorer neurological outcomes.
Between January 1, 2019, and December 31, 2020, SDH patients with GCS scores ranging from 13 to 15 were retrospectively studied. We compared outcomes between patients with a maximum GCS score of 15 and those with scores of either 13 or 14. Independent factors associated with neurological deterioration among patients with a GCS score of 15 were evaluated using multivariate logistic regression (MLR) analysis.
During the study period, 470 patients with SDH and GCS scores between 13 and 15 were examined. Compared to patients with a maximum GCS score (N = 375), those in the GCS 13–14 group (N = 95) showed significantly higher rates of neurological deterioration (33.7% vs. 10.4%, p value <0.001) and neurosurgical interventions (26.3% vs. 16.3%, p value <0.024). Moreover, the GCS 13–14 group had a significantly poorer prognosis than patients with a GCS score of 15 mortality rate: 7.4% vs. 2.4%, p value <0.017; rate of impaired consciousness at discharge: 21.1% vs. 4.0%, p value <0.001; and rate of neurological disability at discharge: 29.5% vs. 6.9%, p value <0.001. The MLR analysis revealed that SDH thickness (odds ratio = 1.127, p value = 0.006) was an independent risk factor for neurological disability at discharge in patients with a GCS score of 15.
Among SDH patients with mild TBI, those with GCS scores of 13–14 exhibited poorer neurological outcomes than those with a maximum GCS score. The thickness of the SDH is positively associated with neurological disability in SDH patients with a maximum GCS score.
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