Global research trends in the effects of exercise on depression: A bibliometric study over the past two decades.

Introduction: With depression's growing global prevalence and substantial impact, effective prevention and management strategies are imperative. Our study aims to perform a thorough bibliometric analysis of existing research on the impact of exercise on depression. Methods: A comprehensive analysis of Web of Science Core Collection publications from 2000 to 2020 was performed, highlighting trends, themes, and influential authors. The study focused on subject categories, source journals, countries/regions, institutions, and prolific authors. Co-citation and keyword analyses revealed key themes, hotspots and the thematic evolution. Results: The multidisciplinary nature of this research is evident across psychiatry, psychology, neuroscience, and sports science. Specific populations such as women, the elderly, and those with chronic illnesses were targeted. Mind-body exercises like yoga and tai chi gained prominence. Co-citation clusters showcased the evolution from early investigations on exercise's impact to recent dose-response and protocol studies. Conclusions: This bibliometric analysis provides insights into the dynamic field of exercise interventions for depression. It underscores the importance of individual differences, calls for guidelines considering comorbidities, and points towards future directions such as exploring mind-body exercise mechanisms and well-designed clinical trials. This study contributes to a comprehensive understanding of the research landscape and informs future endeavors aimed at refining depression treatment through exercise interventions.

Comparison of reperfusion- and central repair-first strategies for acute type a dissection with mesenteric malperfusion: a single-center retrospective cohort study.

BACKGROUND: We seek to compare the early and late outcomes of reperfusion-first versus central repair-first strategies in patients with acute type A dissection (ATAAD) complicated by mesenteric malperfusion. METHODS: Among 68 patients, reperfusion-first strategy with superior mesenteric artery (SMA) stenting was adopted in 31 and central repair-first in 37, based on rupture risk and circulatory compromise, severity, time and mechanisms of mesenteric ischemia. Early and late outcomes were compared between two strategies. Follow-up was 100% at 3.3±1.4 years. RESULTS: Mean age was 50.6±11.4 years (59 males, 86.8%). The reperfusion-first group had more celiac artery involvement (74.2% vs. 48.6%) and peritoneal irritation signs (19.4% vs. 2.7%), while central repair-first group had more tamponade (27% vs. 3.2%). Early mortality was 48.6% (18/37) with central repair-first strategy versus 19.4% (6/31) in reperfusion-first group (P=0.012). Reperfusion-first patients had fewer gastrointestinal complications (12.9% vs. 54.1%, P<0.001) and respiratory failure (3.2% vs. 24.3%, P=0.017). At 5 years, SMA stent patency was 84%, and survival was significantly higher in reperfusion-first patients (80.6% vs. 45.9%, P=0.009), with similar freedom from adverse events between two groups (74.9% vs. 76.0%, P=0.812). Tamponade (hazard ratio [HR], 3.093; P=0.023), peritoneal irritation signs (HR, 8.559; P=0.006), and lactate (mmol/L) (HR, 1.279; P<0.001) were predictors for all-cause mortality. CONCLUSIONS: In this series of ATAAD patients with mesenteric malperfusion, the reperfusion-first strategy with SMA stenting could significantly reduce the mortality risk and achieved favorable late survival and freedom from adverse events. These results argue favorably for the use of the reperfusion-first strategy in such patients.

Tongue Acupuncture to Treat Dysphagia in Patients with Parkinson's Disease: A Randomized Controlled Trial.

Objective: Parkinson's disease (PD) is a chronic degenerative disease that lacks specific treatment. The incidence of dysphagia in patients with PD is 35%-82%. Dysphagia not only affects nutritional intake but also leads to pneumonia, even asphyxia. This study explored the efficacy of tongue acupuncture for treating dysphagia in patients with PD. Materials and Methods: From March 2021 to June 2023, 64 patients with PD-related dysphagia were chosen from Qingdao Central Hospital and the Affiliated Hospital of Qingdao Binhai University, both in Qindao, Shandong, China. The patients were divided into a tongue acupuncture group (n = 32) and a control group (n = 32). The control group was treated with a VitalStim® 5900 Swallowing Disorder Therapeutic Instrument (CA, USA), and the tongue acupuncture group had tongue acupuncture at Juquan (Ex-HN-10) and Haiquan (Ex-HN-11). Swallowing function and nutritional conditions were compared between the 2 groups after all treatments. Results: The total clinical effective rate in the tongue acupuncture group was higher than that of the control group (P < 0.05). The proportion of grade 1 and grade 2 of the 5-scaled Kubota drinking-water test in the tongue acupuncture group was significantly higher than that in the control group (78.13 % versus 31.26 %; P < 0.05), and the proportion of grade 3, grade 4, and grade 5 was significantly lower than that in the control group (21.87 % versus 68.74 %; P < 0.05). After tongue acupuncture, levels of body mass index, upper-arm circumference, triceps skinfold thickness, hemoglobin, serum albumin, and prealbumin were significantly higher than those in the control group (P < 0.05) and the incidence of complications caused by PD was significantly lower than that in the control group (P < 0.05). Conclusions: Treatment of dysphagia in PD by tongue acupuncture significantly improved swallowing function and nutritional level, and decreased the incidence of complications.

A human-specific cytotoxic neopeptide generated by the deafness gene Cingulin.

Accumulation of mutant proteins in cells can induce proteinopathies and cause functional damage to organs. Recently, the Cingulin (CGN) protein has been shown to maintain the morphology of cuticular plates of inner ear hair cells and a frameshift mutation in CGN causes autosomal dominant nonsyndromic hearing loss. Here, we find that the mutant CGN proteins form insoluble aggregates which accumulate intracellularly and lead to cell death. Expression of the mutant CGN in the inner ear results in severe hair cell death and hearing loss in mice, resembling the auditory phenotype in human patients. Interestingly, a human-specific residue (V1112) in the neopeptide generated by the frameshift mutation is critical for the aggregation and cytotoxicity of the mutant human CGN. Moreover, the expression of heat shock factor 1 (HSF1) decreases the accumulation of insoluble mutant CGN aggregates and rescues cell death. In summary, these findings identify mutant-specific toxic polypeptides as a disease-causing mechanism of the deafness mutation in CGN, which can be targeted by the expression of the cell chaperone response regulator HSF1.

Liver-Targeted Nanoparticles Loaded with Cannabidiol Based on Redox Response for Effective Alleviation of Acute Liver Injury.

The purpose of this work was to construct liver-targeted nanoparticles based on the redox response to effectively deliver cannabidiol (CBD) for the prevention of acute liver injury (ALI). CBD-loaded nanoparticles (CBD NPs) with a particle size of 126.5 ± 1.56 nm were prepared using the polymer DA-PP-LA obtained by grafting pullulan polysaccharide with deoxycholic acid (DA) and α-lipoic acid (α-LA). CBD NPs showed typical redox-response release behavior. Interestingly, CBD NPs exhibited admirable liver targeting ability, significantly accumulated in the liver, and effectively promoted the internalization of CBD in liver cells, thus effectively reducing the H2O2-induced oxidative damage of HepG2 cells and avoiding apoptosis. More importantly, CBD NPs effectively prevented CCl4-induced ALI by protecting liver function, ameliorating oxidative stress levels, inhibiting the production of inflammatory factors, and protecting the liver from histological damage. This study provides a promising strategy for achieving targeted delivery of CBD NPs in the liver, thereby effectively preventing ALI.

Robust, superabsorbent and antibacterial polysaccharide-based hybrid-network hydrogels for wound repair.

Hydrogel dressings with multiple functions are ideal options for wound repair. This study developed hydrogel dressings by interpenetrating the physically crosslinked xanthan gum (XG)/carboxylated chitosan (CCS) network and the chemically crosslinked polyacrylamide (PAAm) network via a one-pot method. The XG-CCS/PAAm hydrogels were found to display tunable mechanical properties, due to the formation of strong network structure. The hydrogels exhibited the strongest tensile strength of 0.6 MPa at an XG/CCS ratio of 40/60, while the largest compressive strength of 4.5 MPa is achieved at an XG/CCS ratio of 60/40. Moreover, the hydrogel with an XG/CCS ratio of 60/40 exhibited desirable adhesion strength on porcine skin, which was 3.7 kPa. It also had a swelling ratio, as high as 1200 %. After loading with cephalexin, the XG-CCS/PAAm hydrogels can deliver the antibacterial drugs following a first-order kinetic. As a result, both E. coli and S. aureus can be completely inactivated by the cefalexin-loaded hydrogels after 12 h. Furthermore, the XG-CCS/PAAm hydrogels were found to exhibit excellent biocompatibility as well as effective wound healing ability, as proven by the in vitro and in vivo tests. In this regard, XG-CCS/PAAm hydrogels can act as promising multifunctional wound dressings.

Kaempferol inhibited invasion and metastasis of gastric cancer cells by targeting AKT/GSK3ß pathway based on network pharmacology and molecular docking.

This study aims to explore the mechanisms of the inhibitory effect of kaempferol on the invasion and metastasis of gastric cancer (GC) cells through network pharmacology prediction and experimental verification. It identifies core targets via PPI network analysis and finds that kaempferol binds to these targets well. In vitro experiments showed that kaempferol could inhibit the proliferation, colony formation, migration and invasion of GC cells. Western blotting indicated kaempferol may reduce AKT and GSK3ß phosphorylation, leading to lower expression of invasion-related genes SRC, MMP9, CXCR4, KDR, and MMP2. Overall, kaempferol may prevent migration and invasion of GC cells via the AKT/GSK3ß signaling pathway.

Development and characterization of defatted coconut flour based oleogels: A fat substitute for application in oil-fortified surimi.

This research examined the impact of defatted coconut flour (DCF)-based oleogels on the quality of surimi. Microscopic analysis indicated that the dietary fiber present in DCF could act as the main structure of the oleogels network. The formation of the oleogels network primarily relies on the tensile intramolecular or intermolecular hydrogen bonds between DCF and corn oil. The oleogels displayed oil binding capacity of up to 96.95% and exhibited favorable mechanical and rheological properties. Efforts were undertaken to integrate the acquired oleogels into silver carp surimi to create oil-fortified surimi products. Adding oleogels significantly enhanced the gel strength, texture, and water-holding capacity of surimi compared to adding corn oil. Especially, oleogels containing 5.0 % (w/v) DCF concentration elevated the lipid content in the surimi and preserved the gel and texture properties. Therefore, incorporating oleogels in surimi presents a potential solution for enhancing the nutritional content of surimi products.

Metabolic Profiling of Cochlear Organoids Identifies α-Ketoglutarate and NAD+ as Limiting Factors for Hair Cell Reprogramming.

Cochlear hair cells are the sensory cells responsible for transduction of acoustic signals. In mammals, damaged hair cells do not regenerate, resulting in permanent hearing loss. Reprogramming of the surrounding supporting cells to functional hair cells represent a novel strategy to hearing restoration. However, cellular processes governing the efficient and functional hair cell reprogramming are not completely understood. Employing the mouse cochlear organoid system, detailed metabolomic characterizations of the expanding and differentiating organoids are performed. It is found that hair cell differentiation is associated with increased mitochondrial electron transport chain (ETC) activity and reactive oxidative species generation. Transcriptome and metabolome analyses indicate reduced expression of oxidoreductases and tricyclic acid (TCA) cycle metabolites. The metabolic decoupling between ETC and TCA cycle limits the availability of the key metabolic cofactors, α-ketoglutarate (α-KG) and nicotinamide adenine dinucleotide (NAD+). Reduced expression of NAD+ in cochlear supporting cells by PGC1α deficiency further impairs hair cell reprogramming, while supplementation of α-KG and NAD+ promotes hair cell reprogramming both in vitro and in vivo. These findings reveal metabolic rewiring as a central cellular process during hair cell differentiation, and highlight the insufficiency of key metabolites as a metabolic barrier for efficient hair cell reprogramming.

The effect of active and passive smoking during pregnancy on birth outcomes: A cohort study in Shanghai.

INTRODUCTION: China is the largest tobacco consumer in the world, and tobacco poses a serious threat to the health of pregnant women. However, there are relatively few domestic studies on smoking during pregnancy and childbirth outcomes among pregnant women. The purpose of this study was to analyze the effect of active and passive smoking on pregnant women and their pregnancy outcomes, providing evidence and recommendations for intervention measures. METHODS: This was a cohort study in Shanghai from April 2021 to September 2023. According to the smoking status of pregnant women, they were divided into three groups: active smokers, passive smokers and non-smokers. A self-designed questionnaire was utilized to conduct the survey, and their pregnancy outcomes were tracked and followed up. RESULTS: A total of 3446 pregnant women were included in this study, among which 2.1% were active smokers, 43.5% were passive smokers, and 54.4% were non-smokers. The average age of the pregnant women was 29.9 years, and 41.2% had a university degree or higher. The education level of active smokers and passive smokers was significantly lower than that of non-smokers (p<0.05).The average gestational age of non-smokers was 38.6 weeks, and the birth weight was 3283.2 g, which was higher than those of active smokers and passive smokers (p<0.05). Logistic regression analysis showed that passive smoking increased the likelihood of preterm birth (AOR=1.38; 95% CI: 1.05-1.81), low birth weight (AOR=1.53; 95% CI: 1.10-2.12), and intrauterine growth restriction (AOR=1.35; 95% CI: 1.02-1.79), while active smoking increased the likelihood of preterm birth (AOR=2.98; 95% CI: 1.50-5.90), low birth weight (AOR=4.29; 95% CI: 2.07-8.88), intrauterine growth restriction (AOR=2.70; 95% CI: 1.37-5.33) , and birth defects (AOR=2.66; 95% CI: 1.00-6.97). CONCLUSIONS: Our findings illustrate that active and passive smoking can lead to adverse pregnancy outcomes. This study provides data on the relationship between smoking during pregnancy and delivery outcomes among pregnant women. In the future, we need more effective strategies to protect pregnant women from the harm of tobacco.

The different serum albumin assays influence the prescriptions in children with primary nephrotic syndrome.

The differences between the serum albumin determined by bromocresol green (BCG) and immunonephelometry (IN) were inconsistent in past studies, and the samples were all adults. We sought to determine the differences in children and reveal the impacts of these differences on the clinical diagnosis and treatments of primary nephrotic syndrome (PNS). Repeated measurements from 576 PNS children showed that albumin measured by BCG and IN (ALB-B and ALB-I) were 19.95 (11.15) g/L and 15.30 (11.05) g/L, respectively, and the mean difference was 4.68 g/L (P < 0.001). The cut-offs we calculated for hypoalbuminemia and severe hypoalbuminemia based on the IN were 25 and 15 g/L, which were 5 g/L lower than the cut-offs recommended by KIDGO, respectively. A pair of historical control samples (206 vs. 216) with ALB-B or ALB-I showed that the proportion of severe hypoalbuminemia was 14.60% greater in IN group (75.20% vs. 60.60%, P < 0.001). The misdiagnosis rate of severe hypoalbuminemia by IN was 33.77% when 20 g/L rather than 15 g/L was used as the cut-off. Furthermore, the proportion of patients receiving albumin injections increased by 10.20%, and the average consumption increased by 97.06% (P = 0.01) along with the use of IN. So, our results suggested that the difference between ALB-B and ALB-I led to misdiagnosis and prescription abuse in PNS children.

Indeno[1,2,3-cd]pyrene enhances the sensitivity of airway epithelial cells to ferroptosis and aggravates asthma.

Particulate matter of aerodynamic diameter ≤2.5 µm (PM2.5) exposure induces oxidative stress in lung tissues. Ferroptosis is a form of regulated cell death based on oxidative damage and lipid peroxidation. Whether PM2.5 exposure-induced oxidative stress can promote ferroptosis to aggravate asthma is not known. To investigate if PM2.5 exposure induces oxidative stress to promote ferroptosis and influence asthma development, a cockroach extract-induced asthma model in mice was used for in vivo studies. Airway epithelial cell (AEC) ferroptosis was detected by assays (CCK8, malonaldehyde, and 4-hydroxynonenal). Molecular mechanisms were investigated by real-time reverse transcription-quantitative polymerase chain reaction, western blotting, flow cytometry, liquid chromatography-tandem mass spectrometry, and chromatin immunoprecipitation. We found that exposure to PM2.5 and Indeno[1,2,3-cd] pyrene (IP; one of the prominent absorbed polycyclic aromatic hydrocarbons in PM2.5) enhanced the sensitivity of AECs to ferroptosis to aggravate asthma, whereas ferroptosis inhibitors and cytosolic phospholipase A2 (cPLA2) inhibitors reversed this augmented inflammatory response in mice suffering from asthma. IP treatment enhanced cPLA2 expression/activation through aryl hydrocarbon receptor (AhR) genomic and non-genomic pathways, resulting in arachidonic-acid release to promote the sensitivity of AECs to ferroptosis. IP exposure enhanced the release of leukotriene-B4 from lung macrophages, resulting in enhanced expression of acyl-coA synthetase long chain family member4 (ACSL4) and the sensitivity of AECs to ferroptosis. This finding suggests that exposure to PM2.5 and IP promote ferroptosis sensitivity in AECs to aggravate asthma, which may provide new targets for the prevention and treatment of asthma.

Dynamics of antibiotic resistance genes during manure composting: Reduction in herbivores manure and accumulation in carnivores.

The elevated levels of antibiotic resistance genes (ARGs) in livestock manure represent a significant threat to both the environment and human health. Composting has been recognized as an effective strategy to mitigate the abundance of ARGs in manure. However, notable rebounds in ARGs abundance have been observed during this process. This study explored the changes in ARGs abundance and the underlying influencing factors during the composting of carnivore (chicken and pig) and herbivore (sheep and cow) manures, along with mushroom residues. The findings revealed that the total relative abundance of ARGs increased by 6.96 and 10.94 folds in chicken and pig manure composts, respectively, whereas it decreased by a remarkable 91.72% and 98.37% in sheep and cow manure composts. Nitrogen content emerged as the primary physicochemical factors governing the abundance of ARGs in chicken and pig manure composts. Conversely, carbon content played a pivotal role in determining ARGs abundance in chicken and pig manure composts. Furthermore, the presence of dominant hosts, such as Corynebacterium, Bacillus, and Clostridium, along with emerging bacteria like Thermobifida, Saccharomonospora, and Actinomadura, contributed significantly to the enrichment of total ARGs, including tetG, tetO, tetX, and sul2, in chicken and pig manure composts. The coexistence of these genes with mobile genetic elements and a plethora of host bacteria, coupled with their high abundance, renders them particularly high-risk ARGs. On the other hand, the observed decrease in the abundance of total ARGs in sheep and cow manure composts can be attributed to the decline in the population of host bacteria, specifically Atopostipes, Psychrobacter, and Corynebacterium. Collectively, these results provide crucial insights into the management of ARGs risks and offer essential theoretical support for enhancing the safe utilization of organic fertilizer in agriculture.

Association between gut microbiota and diabetic nephropathy: a two-sample Mendelian randomization study.

Background: To clarify the causal relationship between gut microbiota and diabetic nephropathy (DN), we employed Mendelian randomization (MR). Despite a strong correlation observed, establishing causality is still unclear. By utilizing MR, we aimed to investigate this relationship further and shed light on the potential causal effect of gut microbiota on DN. Methods: Genetic instrumental variables for gut microbiota were obtained from a GWAS with 18340 participants. DN summary statistics (1032 cases, 451248 controls) were sourced from a separate GWAS. The primary analysis used the inverse-variance weighted (IVW) method. Reverse MR analysis was conducted to explore reverse causation. Rigorous sensitivity analyses were performed to ensure the resilience and reliability of the study's findings. Results: We found two bacterial traits associated with an increased risk of DN: genus LachnospiraceaeUCG008 (OR: 1.4210; 95% CI: 1.0450, 1.9322; p = 0.0250) and genus Terrisporobacter (OR: 1.9716; 95% CI: 1.2040, 3.2285; p = 0.0070). Additionally, phylum Proteobacteria (OR: 0.4394; 95% CI: 0.2721, 0.7096; p = 0.0008) and genus Dialister (OR: 0.4841; 95% CI: 0.3171, 0.7390; p = 0.0008) were protective against DN. Sensitivity analyses consistently supported these results. In the reverse MR analysis, no statistically significant associations were observed between DN and these four bacterial traits. Conclusions: Our analyses confirmed a potential causal relationship between certain gut microbiota taxa and the risk of DN. However, additional studies are required to elucidate the underlying mechanisms through which gut microbiota influences the development of DN.

Combination of static and dynamic neural imaging features to distinguish sensorineural hearing loss: a machine learning study.

Purpose: Sensorineural hearing loss (SNHL) is the most common form of sensory deprivation and is often unrecognized by patients, inducing not only auditory but also nonauditory symptoms. Data-driven classifier modeling with the combination of neural static and dynamic imaging features could be effectively used to classify SNHL individuals and healthy controls (HCs). Methods: We conducted hearing evaluation, neurological scale tests and resting-state MRI on 110 SNHL patients and 106 HCs. A total of 1,267 static and dynamic imaging characteristics were extracted from MRI data, and three methods of feature selection were computed, including the Spearman rank correlation test, least absolute shrinkage and selection operator (LASSO) and t test as well as LASSO. Linear, polynomial, radial basis functional kernel (RBF) and sigmoid support vector machine (SVM) models were chosen as the classifiers with fivefold cross-validation. The receiver operating characteristic curve, area under the curve (AUC), sensitivity, specificity and accuracy were calculated for each model. Results: SNHL subjects had higher hearing thresholds in each frequency, as well as worse performance in cognitive and emotional evaluations, than HCs. After comparison, the selected brain regions using LASSO based on static and dynamic features were consistent with the between-group analysis, including auditory and nonauditory areas. The subsequent AUCs of the four SVM models (linear, polynomial, RBF and sigmoid) were as follows: 0.8075, 0.7340, 0.8462 and 0.8562. The RBF and sigmoid SVM had relatively higher accuracy, sensitivity and specificity. Conclusion: Our research raised attention to static and dynamic alterations underlying hearing deprivation. Machine learning-based models may provide several useful biomarkers for the classification and diagnosis of SNHL.

FGF21 attenuates salt-sensitive hypertension via regulating HNF4α/ACE2 axis in the hypothalamic paraventricular nucleus of mice.

BACKGROUND: Fibroblast growth factor 21 (FGF21) has a protective effect against cardiovascular disease. However, the role of FGF21 in hypertension remains elusive. METHODS: Ten-week-old male C57BL/6 mice were randomly divided into normal-salt (NS) group, NS+FGF21 group, deoxycorticosterone acetate-salt (DOCA) group and DOCA+FGF21 group. The mice in NS group underwent uninephrectomy without receiving DOCA and 1% NaCl and the mice in DOCA group were subjected to uninephrectomy and DOCA-salt (DOCA and 1% NaCl) treatment for 6 weeks. At the same time, the mice were infused with vehicle (artificial cerebrospinal fluid, aCSF) or FGF21 (1 mg/kg) into the bilateral paraventricular nucleus (PVN) of mice. RESULTS: Here, we showed that FGF21 treatment lowered DOCA salt-induced inflammation and oxidative stress in the PVN, which reduced sympathetic nerve activity and hypertension. Mechanistically, FGF21 treatment decreased the expression of HNF4α and inhibited the binding activity of HNF4α to the promoter region of ACE2 in the PVN of DOCA salt-treated mice, which further up-regulated ACE2/Ang (1-7) signals in the PVN. In addition, ACE2 deficiency abolished the protective effect of FGF21 in DOCA salt-treated mice, suggesting that FGF21-mediated antihypertensive effect was dependent on ACE2. CONCLUSIONS: The results demonstrate that FGF21 protects against salt-sensitive hypertension via regulating HNF4α/ACE2/Ang (1-7) axis in the PVN of DOCA salt-treated mice via multi-organ crosstalk between liver, brain and blood vessels.

Genetic variants in UNC93B1 predispose to childhood-onset systemic lupus erythematosus.

Rare genetic variants in toll-like receptor 7 (TLR7) are known to cause lupus in humans and mice. UNC93B1 is a transmembrane protein that regulates TLR7 localization into endosomes. In the present study, we identify two new variants in UNC93B1 (T314A, located proximally to the TLR7 transmembrane domain, and V117L) in a cohort of east Asian patients with childhood-onset systemic lupus erythematosus. The V117L variant was associated with increased expression of type I interferons and NF-κB-dependent cytokines in patient plasma and immortalized B cells. THP-1 cells expressing the variant UNC93B1 alleles exhibited exaggerated responses to stimulation of TLR7/-8, but not TLR3 or TLR9, which could be inhibited by targeting the downstream signaling molecules, IRAK1/-4. Heterozygous mice expressing the orthologous Unc93b1V117L variant developed a spontaneous lupus-like disease that was more severe in homozygotes and again hyperresponsive to TLR7 stimulation. Together, this work formally identifies genetic variants in UNC93B1 that can predispose to childhood-onset systemic lupus erythematosus.

Microplastics increase the microbial functional potential of greenhouse gas emissions and water pollution in a freshwater lake: A metagenomic study.

Aquatic ecosystems are being increasingly polluted by microplastics (MPs), which calls for an understanding of how MPs affect microbially driven biogenic element cycling in water environments. A 28-day incubation experiment was conducted using freshwater lake water added with three polymer types of MPs (i.e., polyethylene, polypropylene, polystyrene) separately or in combination at a concentration of 1 items/L. The effects of various MPs on microbial communities and functional genes related to carbon, nitrogen, phosphorus, and sulfur cycling were analyzed using metagenomics. Results showed that Sphingomonas and Novosphingobium, which were indicator taxa (genus level) in the polyethylene treatment group, made the largest functional contribution to biogenic element cycling. Following the addition of MPs, the relative abundances of genes related to methane oxidation (e.g., hdrD, frhB, accAB) and denitrification (napABC, nirK, norB) increased. These changes were accompanied by increased relative abundances of genes involved in organic phosphorus mineralization (e.g., phoAD) and sulfate reduction (cysHIJ), as well as decreased relative abundances of genes involved in phosphate transport (phnCDE) and the SOX system. Findings of this study underscore that MPs, especially polyethylene, increase the potential of greenhouse gas emissions (CO2, N2O) and water pollution (PO43-, H2S) in freshwater lakes at the functional gene level.