Climate-driven changes of global marine mercury cycles in 2100.

Human exposure to monomethylmercury (CH3Hg), a potent neurotoxin, is principally through the consumption of seafood. The formation of CH3Hg and its bioaccumulation in marine food webs experience ongoing impacts of global climate warming and ocean biogeochemistry alterations. Employing a series of sensitivity experiments, here we explicitly consider the effects of climate change on marine mercury (Hg) cycling within a global ocean model in the hypothesized twenty-first century under the business-as-usual scenario. Even though the overall prediction is subjected to significant uncertainty, we identify several important climate change impact pathways. Elevated seawater temperature exacerbates elemental Hg (Hg0) evasion, while decreased surface wind speed reduces air-sea exchange rates. The reduced export of particulate organic carbon shrinks the pool of potentially bioavailable divalent Hg (HgII) that can be methylated in the subsurface ocean, where shallower remineralization depth associated with lower productivity causes impairment of methylation activity. We also simulate an increase in CH3Hg photodemethylation potential caused by increased incident shortwave radiation and less attenuation by decreased sea ice and chlorophyll. The model suggests that these impacts can also be propagated to the CH3Hg concentration in the base of the marine food web. Our results offer insight into synergisms/antagonisms in the marine Hg cycling among different climate change stressors.

Bradyrhizobium japonicum HmuP is an RNA-binding protein that positively controls hmuR operon expression by suppression of a negative regulatory RNA element in the 5' untranslated region.

The hmuR operon encodes proteins for the uptake and utilization of heme as a nutritional iron source in Bradyrhizobium japonicum. The hmuR operon is transcriptionally activated by the Irr protein and is also positively controlled by HmuP by an unknown mechanism. An hmuP mutant does not express the hmuR operon genes nor does it grow on heme. Here, we show that hmuR expression from a heterologous promoter still requires hmuP, suggesting that HmuP does not regulate at the transcriptional level. Replacement of the 5' untranslated region (5'UTR) of an HmuP-independent gene with the hmuR 5'UTR conferred HmuP-dependent expression on that gene. Recombinant HmuP bound an HmuP-responsive RNA element (HPRE) within the hmuR 5'UTR. A 2 nt substitution predicted to destabilize the secondary structure of the HPRE abolished both HmuP binding activity in vitro and hmuR expression in cells. However, deletion of the HPRE partially restored hmuR expression in an hmuP mutant, and it rescued growth of the hmuP mutant on heme. These findings suggest that the HPRE is a negative regulatory RNA element that is suppressed when bound by HmuP to express the hmuR operon.

Arm symptom pattern among breast cancer survivors with and without lymphedema: a contemporaneous network analysis.

BACKGROUND: Arm symptoms commonly endure in post-breast cancer period and persist into long-term survivorship. However, a knowledge gap existed regarding the interactions among these symptoms. This study aimed to construct symptom networks and visualize the interrelationships among arm symptoms in breast cancer survivors (BCS) both with and without lymphedema (LE). PATIENTS AND METHODS: We conducted a secondary analysis of 3 cross-sectional studies. All participants underwent arm circumference measurements and symptom assessment. We analyzed 17 symptoms with a prevalence >15%, identifying clusters and covariates through exploratory factor and linear regression analysis. Contemporaneous networks were constructed with centrality indices calculated. Network comparison tests were performed. RESULTS: 1116 cases without missing data were analyzed, revealing a 29.84% prevalence of LE. Axillary lymph node dissection [ALND] (vs sentinel lymph node biopsy [SLNB]), longer post-surgery duration, and radiotherapy significantly impacted overall symptom severity (P < .001). "Lymphatic Stasis," "Nerve Injury," and "Movement Limitation" symptom clusters were identified. Core symptoms varied: tightness for total sample network, firmness for non-LE network, and tightness for LE network. LE survivors reported more prevalent and severe arm symptoms with stronger network connections than non-LE group (P = .010). No significant differences were observed among different subgroups of covariates (P > .05). Network structures were significantly different between ALND and SLNB groups. CONCLUSION: Our study revealed arm symptoms pattern and interrelationships in BCS. Targeting core symptoms in assessment and intervention might be efficient for arm symptoms management. Future research is warranted to construct dynamic symptom networks in longitudinal data and investigate causal relationships among symptoms.

Topical ophthalmic instillation of engineered hMSCs-derived exosomes: A novel non-invasive therapeutic strategy for ocular posterior-segment disorder.

Due to the presence of protective mechanisms and blood-ocular barriers in the eye, drugs aimed at treating posterior segment ophthalmic disorder have to be administrated mostly through periocular or intravitreal injection. In the current study, we sought to investigate whether topical ophthalmic instillation of human mesenchymal stem cells (hMSCs)-derived exosomes can prevent and treat experimental autoimmune uveitis (EAU), a posterior segment ophthalmic disease induced in animals and considered a model of human autoimmune diseases of the eye. Our studies reveal that topical ophthalmic instillation of hMSCs-derived exosomes can effectively ameliorate EAU. More importantly, we demonstrate that exosomes modified by trans-activator of transcription peptide (TAT) were more effective than naive exosomes in penetrating ocular barrier and preventing/treating EAU. Taken together, these results indicate that topical ophthalmic instillation of TAT-peptide modified exosomes represents a novel non-invasive therapeutic strategy for posterior-segment ophthalmic disorders.

Contemporaneous Symptom Networks of Breast Cancer-Related Upper Limb Lymphedema: A Network Analysis.

BACKGROUND: Upper limb lymphedema (ULL) is a common and deliberating complication for breast cancer survivors (BCSs). Breast cancer survivors with ULL reported a wide range of symptoms. However, little is known about symptom patterns and interrelationships among them. This study was designed to explore symptom clusters and construct symptom networks of ULL-related symptoms among BCSs and to identify the core symptoms. METHODS: This study is a secondary data analysis using datasets from three cross-sectional studies of BCSs in China. A total of 341 participants with maximum interlimb circumference ≥2 cm and complete responses in Part I of the Breast Cancer and Lymphedema Symptom Experience Index were included. Symptom clusters were identified through principal component analysis, and multiple linear regression analysis was employed to explore factors associated with severity of overall ULL-related symptoms. A contemporaneous network with 20 frequently reported symptoms were constructed after controlling for covariates. RESULTS: Three symptom clusters, including lymph stasis symptom cluster, nerve symptom cluster, and movement limitation symptom cluster, were identified. Postsurgery time, axillary lymph node dissection, and radiotherapy were associated with the severity of ULL-related symptoms. Tightness (rs = 1.379; rscov = 1.097), tingling (rs = 1.264; rscov = 0.925), and firmness (rs = 1.170; rscov = 0.923) were the most central symptoms in both networks with and without covariates. CONCLUSIONS: Breast cancer survivors with ULL experienced severe symptom burden. Tightness, tingling, and firmness were core symptoms of ULL among BCSs. Our findings demonstrated that the assessment and targeted intervention of specific core symptoms might help to relive effectively the burden of ULL-related symptom among BCSs.

Advances in the application of extracellular vesicles derived from three-dimensional culture of stem cells.

Stem cells (SCs) have been used therapeutically for decades, yet their applications are limited by factors such as the risk of immune rejection and potential tumorigenicity. Extracellular vesicles (EVs), a key paracrine component of stem cell potency, overcome the drawbacks of stem cell applications as a cell-free therapeutic agent and play an important role in treating various diseases. However, EVs derived from two-dimensional (2D) planar culture of SCs have low yield and face challenges in large-scale production, which hinders the clinical translation of EVs. Three-dimensional (3D) culture, given its ability to more realistically simulate the in vivo environment, can not only expand SCs in large quantities, but also improve the yield and activity of EVs, changing the content of EVs and improving their therapeutic effects. In this review, we briefly describe the advantages of EVs and EV-related clinical applications, provide an overview of 3D cell culture, and finally focus on specific applications and future perspectives of EVs derived from 3D culture of different SCs.

Prognostic nomogram for patients with tongue squamous cell carcinoma: A SEER-based study.

OBJECTIVES: In order to predict the patients' prognosis with tongue squamous cell carcinoma (SCC), this study set out to develop a clinically useful and trustworthy prognostic nomogram. SUBJECTS AND METHODS: The Surveillance, Epidemiology, and End Results (SEER) Program was used to compile clinical information on patients with tongue SCC between 2010 and 2015. The likelihood of Cancer-Specific Survival (CSS) and Overall Survival (OS) for specific patients was predicted using a prognostic nomogram created with the help of the RStudio software. The nomogram's predictive ability was evaluated using the consistency index (C-index) and decision curve analysis, and the nomogram was calibrated for 1-, 2-, 3-, 5-, and 10-year CSS and OS. RESULTS: Patients numbering 6453were enrolled in this study. The primary cohort (3895) and validation cohort (2558) were each randomly assigned. Sex, age, tumor-node-metastasis (TNM) stage, surgery, chemotherapy, and radiation were significant risk factors for OS, whereas age, TNM stage, surgery, chemotherapy, and radiotherapy were significant risk factors for CSS. Additionally, C-index and calibration curves indicated that the prognostic nomogram prediction and the actual observation in both cohorts would be very coherent. CONCLUSIONS: The predictive nomogram created in this study can offer patients with tongue SCC customized treatment and survival risk assessment.

Plastic waste release caused by COVID-19 and its fate in the global ocean.

The COVID-19 pandemic has led to an increased demand for single-use plastics that intensifies pressure on an already out-of-control global plastic waste problem. While it is suspected to be large, the magnitude and fate of this pandemic-associated mismanaged plastic waste are unknown. Here, we use our MITgcm ocean plastic model to quantify the impact of the pandemic on plastic discharge. We show that 8.4 ± 1.4 million tons of pandemic-associated plastic waste have been generated from 193 countries as of August 23, 2021, with 25.9 ± 3.8 thousand tons released into the global ocean representing 1.5 ± 0.2% of the global total riverine plastic discharge. The model projects that the spatial distribution of the discharge changes rapidly in the global ocean within 3 y, with a significant portion of plastic debris landing on the beach and seabed later and a circumpolar plastic accumulation zone will be formed in the Arctic. We find hospital waste represents the bulk of the global discharge (73%), and most of the global discharge is from Asia (72%), which calls for better management of medical waste in developing countries.

Destabilization of ultra-instantaneous ultra-high-temperature sterilized milk stored at different temperatures.

Ultra-instantaneous UHT (UI-UHT, >155°C, <0.1 s) treated milk exhibits higher retention of active protein than regular UHT milk. However, UI-UHT products demonstrate increased susceptibility to destabilization during storage. This study aimed at monitoring the destabilizing process of UI-UHT milk across different storage temperatures and uncovering its potential mechanisms. Compared with regular UHT treatment, ultra-instantaneous treatment markedly accelerated the milk's destabilization process. Aged gel formation occurred after 45 d of storage at 25°C, whereas creaming and sedimentation were observed after 15 d at 37°C. To elucidate the instability mechanism, measurements of plasmin activity, protein hydrolysis levels, and proteomics of the aged gel were conducted. In UI-UHT milk, plasmin activity, and protein hydrolysis levels significantly increased during storage. Excessive protein hydrolysis at 37°C resulted in sedimentation, whereas moderate hydrolysis and an increase in protein particle size at 25°C resulted in aged gel formation. Proteomics analysis results indicated that the aged gel from UI-UHT milk contained intact caseins, major whey proteins, and their derived peptides. Furthermore, specific whey proteins including albumin, lactotransferrin, enterotoxin-binding glycoprotein PP20K, and MFGM proteins were identified in the gel. Additionally, MFGM proteins in UI-UHT milk experienced considerable hydrolysis during storage, contributing to fat instability. This study lays a theoretical foundation for optimizing UI-UHT milk storage conditions to enhance the quality of liquid milk products.

Transcriptomic analysis provides insight into the genetic regulation of shade avoidance in Aegilops tauschii.

BACKGROUND: Weeds are not only economically important but also fascinating models for studying the adaptation of species in human-mediated environments. Aegilops tauschii is the D-genome donor species of common wheat but is also a weed that influences wheat production. How shading stress caused by adjacent wheat plants affects Ae. tauschii growth is a fundamental scientific question but is also important in agriculture, such as for weed control and wheat breeding. RESULT: The present study indicated that shade avoidance is a strategy of Ae. tauschii in response to shading stress. Ae. tauschii plants exhibited growth increases in specific organs, such as stem and leaf elongation, to avoid shading. However, these changes were accompanied by sacrificing the growth of other parts of the plants, such as a reduction in tiller number. The two reverse phenotype responses seem to be formed by systemically regulating the expression of different genes. Fifty-six genes involved in the regulation of cell division and cell expansion were found to be downregulated, and one key upstream negative regulator (RPK2) of cell division was upregulated under shading stress. On the other hand, the upregulated genes under shading stress were mainly enriched in protein serine/threonine kinase activity and carbon metabolism, which are associated with cell enlargement, signal transduction and energy supply. The transcription factor WRKY72 may be important in regulating genes in response to shading stress, which can be used as a prior candidate gene for further study on the genetic regulation of shade avoidance. CONCLUSIONS: This study sheds new light on the gene expression changes and molecular processes involved in the response and avoidance of Ae. tauschii to shading stress, which may aid more effective development of shading stress avoidance or cultivars in wheat and other crops in the future.