Levothyroxine for subclinical hypothyroidism during pregnancy: an updated systematic review and meta-analysis of randomized controlled trials.

PURPOSE: We aimed to perform a systematic review and meta-analysis addressing the efficacy of levothyroxine therapy in pregnant women with subclinical hypothyroidism considering most recent evidence and subgroups of interest for clinical practice. METHODS: PubMed, Embase, and Cochrane Central were searched from inception for randomized controlled trials (RCTs) comparing levothyroxine with placebo or no intervention in pregnant women with subclinical hypothyroidism. We used a random-effects model and conducted subgroup analyses based on thyroid peroxidase antibody status, thyroid stimulating hormone levels, fertility treatment, and recurrent miscarriage. RESULTS: We included 11 RCTs comprising 2,749 pregnant women with subclinical hypothyroidism. Patients treated with levothyroxine (1,439; 52.3%) had significantly lower risk of pregnancy loss (risk ratio 0.69; 95% confidence interval 0.52-0.91; p < 0.01; 6 studies). However, there was no significant association between levothyroxine and live birth (risk ratio 1.01; 95% confidence interval 0.99-1.03; p = 0.29; 8 studies). No statistically significant interaction was observed across subgroups (p > 0.05). CONCLUSION: Levothyroxine replacement therapy for subclinical hypothyroidism during pregnancy may decrease pregnancy loss when early prescribed. Nevertheless, further investigation is needed in patients with thyroid stimulating hormone above four milliunits per liter, especially when associated with recurrent miscarriage or infertility.

Exosome-mediated repair of spinal cord injury: a promising therapeutic strategy.

Spinal cord injury (SCI) is a catastrophic injury to the central nervous system (CNS) that can lead to sensory and motor dysfunction, which seriously affects patients' quality of life and imposes a major economic burden on society. The pathological process of SCI is divided into primary and secondary injury, and secondary injury is a cascade of amplified responses triggered by the primary injury. Due to the complexity of the pathological mechanisms of SCI, there is no clear and effective treatment strategy in clinical practice. Exosomes, which are extracellular vesicles of endoplasmic origin with a diameter of 30-150 nm, play a critical role in intercellular communication and have become an ideal vehicle for drug delivery. A growing body of evidence suggests that exosomes have great potential for repairing SCI. In this review, we introduce exosome preparation, functions, and administration routes. In addition, we summarize the effect and mechanism by which various exosomes repair SCI and review the efficacy of exosomes in combination with other strategies to repair SCI. Finally, the challenges and prospects of the use of exosomes to repair SCI are described.

[Effects of Polystyrene Microplastics Combined with Cadmium Contamination on Soil Physicochemical Properties and Physiological Ecology of Lactuca sativa].

Contaminants such as microplastics (MPs) and heavy metals are commonly found in soils, both of which are extremely difficult to degrade and can easily form compound contamination, altering the physicochemical properties of the soil and thus potentially changing the growth and physiological and ecological characteristics of plants. In order to study the effects of the combined contamination of soil MPs and heavy metals on soil properties and plant growth, polystyrene microplastics (PS-MPs) with a particle size of 3 µm and the heavy metal cadmium were selected in the study. The changes in the physicochemical properties of soil and their effects on lettuce (Lactuca sativa) seed germination and seedling growth were studied at various exposure concentrations of PS-MPs (0, 10, 50, 100, 200, and 400 mg·kg-1) and combined with different Cd contamination concentrations (0, 1.2, and 6.0 mg·kg-1), respectively. The results showed that soil organic matter (SOM), available phosphorus (AP), alkali-hydrolysable nitrogen (AHN), and available kalium (AK) showed significant decreases as the intensity of PS-MPs combined with Cd contamination increased. Simultaneously, PS-MPs combined with Cd contamination also significantly reduced the germination rate of lettuce seeds, but low concentrations of PS-MPs slowed down the effect of Cd (6.0 mg·kg-1) contamination on lettuce seeds, and high concentrations of PS-MPs enhanced the effect of Cd (6.0 mg·kg-1). The fresh weight, dry weight, and plant height of lettuce seedlings showed an increasing and then decreasing trend with increasing exposure to PS-MPs. Chlorophyll content, superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) showed a decreasing trend, whereas malondialdehyde (MDA) content showed an overall increasing trend under different Cd concentrations. The main physicochemical indicators of the soil were negatively correlated with MDA of lettuce seedlings, whereas other indicators of the seedlings were positively correlated. The combined contamination of PS-MPs and Cd could affect the germination of plant seeds and the physiological and ecological characteristics of seedlings by changing the physicochemical properties of the soil. Both exposure to single PS-MPs contaminants and the combination of PS-MPs with Cd inhibited the germination of lettuce seeds and affected the physiological activities of their seedlings, and the inhibition was significantly increased with increasing exposure. Low exposure to PS-MPs or the combination of PS-MPs with Cd contamination exhibited a promotive effect on lettuce seedling growth. High exposure to PS-MPs combined with Cd contamination exhibited significant ecological effects on lettuce seedlings, and high exposure to PS-MPs exacerbated the ecotoxicological effects of Cd contaminants on lettuce seedlings, and PS-MPs and Cd exhibited synergistic effects. The results can provide some reference for assessing the ecological effects of MPs and heavy metal pollution in soil-plant systems.

[Distribution Characteristics of Microplastic Surface Bacterial Communities Under Flooded and Non-flooded Conditions in Nanjishan Wetland of Poyang Lake].

Plastic particles smaller than 5 mm in size are known as microplastics which are widespread in the environment and can cause several negative effects. Moreover, only a few studies have focused on the relationship between microplastics and microbes in the natural wetland ecosystem. In this study, microplastics were collected from sediment, water, and sediment flooded and non-flooded conditions in the lake wetland of Poyang Lake as the study area. The structural distribution of bacterial community on sediment, water, and microplastics were analyzed using 16S high-throughput sequencing. The results of the α-diversity analysis showed that the bacterial abundance and diversity on the surface of microplastics were significantly different from those in the environment and were lower than those in the surrounding environment in both flooded and non-flooded conditions. The results of the principal co-ordinates analysis indicated that the bacterial community on the surface of microplastics was more influenced by the sediment in non-flooded conditions and by the water in flooded conditions. The structure of the bacterial community on the microplastic surface also showed significant differences from the surrounding environment, with the sediment mainly consisting of several other bacterial genera with <1% abundance, whereas the bacterial community on the microplastics had clearly dominant species. The relative abundance of Proteobacteria on the microplastic surfaces increased significantly in the non-flooded condition compared to that in the water and sediment samples, whereas the relative abundance of Bacteroidota on the microplastic surface increased in the flooded condition. The genus Flavobacterium, Massilia, and Pseudomonas were the most abundant in the non-flooded state, and the genus Flavobacterium was the most abundant in the flooded state. In this study, Pseudomonas spp. was the focus of future research on plastic biodegradation. This study can further improve the understanding of microplastic pollution in wetland ecosystems and provide a theoretical basis for lake environmental management.

Monitoring of low-molecular-weight protein aggregation by CE-SDS as a complementary method to SE-HPLC.

Capillary electrophoresis with sodium dodecyl sulfate (CE-SDS) has long been proven to have excellent performance in the analysis and characterization of therapeutic proteins. However, it is rarely used for the detection of low-molecular-weight proteins or peptides. Our research has proved the ability of CE-SDS to characterize the purity of low-molecular-weight proteins (i.e., <10 kDa) and even polypeptides. In this article, insulin glargine was used as a model protein, and CE-SDS was used to analyze the samples damaged by heating and light exposure. The monomers, dimers, and trimers of insulin glargine were effectively separated, and the results of the mass spectrometry also confirmed the existence of two kinds of insulin aggregates. For comparison, the size-exclusion high-performance liquid chromatography (SE-HPLC) only showed a single aggregate peak. In addition, the denaturation conditions caused only the covalent aggregates to appear in the CE-SDS analysis. These advantages also make CE-SDS an excellent supplementary technology to the traditional SE-HPLC, providing biopharmaceutical analysts with more information.

Depressive Symptoms in Patients with Fibromyalgia: Current Evidence and Preventive Approaches.

Fibromyalgia is a chronic inflammatory disease characterized by multifocal pain, fatigue, and cognitive impairment [...].

Identification of LRRK2 gene related to sarcopenia and neuroticism using weighted gene co-expression network analysis.

BACKGROUND: Sarcopenia is reported to be associated with neuroticism, but the mechanisms are not fully understood. Thus, it's of vital importance to elucidate the molecular mechanism of sarcopenia and neuroticism and to explore the potential molecular target of medical therapies for sarcopenia and neuroticism. METHODS: The expression datasets (sarcopenia: GSE111006 and neuroticism: GSE60491) were downloaded from the Gene Expression Omnibus. Weighted gene co-expression network analysis (WGCNA) was used to build the gene co-expression network, screen important modules, and filter the hub genes. Genes with significance over 0.2 and a module membership over 0.8 were hub genes. The overlapped hub genes between sarcopenia and neuroticism were defined as key genes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed for the genes in modules with clinical interest. RESULTS: In this study, we identified 28 gene modules for sarcopenia and 7 for neuroticism by WGCNA. The key modules of sarcopenia and neuroticism were the tan and turquoise modules, respectively. Hub genes of sarcopenia and neuroticism were 20 genes and 107 genes, respectively. The function enrichment found that apoptosis was the common pathway for sarcopenia and neuroticism. Finally, LRRK2 was identified as key genes. LIMITATIONS: The sarcopenia dataset contained fewer samples. CONCLUSION: Based on WGCNA, our study identified apoptosis pathway and LRRK2 that acted as essential components in the etiology of sarcopenia and neuroticism, which may enhance our fundamental knowledge of the molecular mechanisms underlying the disease.

Robot-assisted versus navigation-assisted screw placement in spinal vertebrae.

PURPOSE: Both robots and navigation are effective strategies for optimizing screw placement, as compared to freehand placement. However, few studies have compared the accuracy and efficiency of these two techniques. Thus, the purpose of this study is to compare the accuracy and efficiency of robotic and navigation-assisted screw placement in the spinal vertebrae. METHODS: The 24 spine models were divided into a robot- and navigation-assisted groups according to the left and right sides of the pedicle. The C-arm transmits image data simultaneously to the robot and navigates using only one scan. After screw placement, the accuracy of the two techniques were compared using "angular deviation" and "Gertzbein and Robbins scale" in different segments (C1-7, T1-4, T5-8, T9-12, and L1-S1). In addition, operation times were compared between robot- and navigation-assisted groups. RESULTS: Robots and navigation systems can simultaneously assist in screw placement. The robot-assisted group had significantly less angular deviation than the navigation-assisted group from C1 to S1 (p < 0.001). At the C1-7 and T1-4 segments, the robot-assisted group had a higher rate of acceptable screws than the robot-assisted group. However, at the T5-8, T9-12, and L1-S1 segments, no significant difference was found in the incidence of acceptable screws between the two groups. Moreover, robot-assisted screw placement required less operative time than navigation (p < 0.05). CONCLUSION: The robot is more accurate and efficient than navigation in aiding screw placement. In addition, robots and navigation can be combined without increasing the number of fluoroscopic views.

Effects of polyol excipient stability during storage and use on the quality of biopharmaceutical formulations.

Biopharmaceuticals are formulated using a variety of excipients to maintain their storage stability. However, some excipients are prone to degradation during repeated use and/or improper storage, and the impurities generated by their degradation are easily overlooked by end users and are usually not strictly monitored, affecting the stability of biopharmaceuticals. In this study, we evaluated the degradation profile of polyol excipient glycerol during repeated use and improper storage and identified an unprecedented cyclic ketal impurity using gas chromatography with mass spectrometry (GC-MS). The other polyol excipient, mannitol, was much more stable than glycerol. The effects of degraded glycerol and mannitol on the stability of the model biopharmaceutical pentapeptide, thymopentin, were also evaluated. The thymopentin content was only 66.4% in the thymopentin formulations with degraded glycerol, compared to 95.8% in other formulations after the stress test. Most glycerol impurities (i.e., aldehydes and ketones) reacted with thymopentin, affecting the stability of thymopentin formulations. In conclusion, this work suggests that more attention should be paid to the quality changes of excipients during repeated use and storage. Additional testing of excipient stability under real or accelerated conditions by manufacturers would help avoid unexpected and painful results.

Integrating Network Pharmacology and Transcriptomic Strategies to Explore the Pharmacological Mechanism of Hydroxysafflor Yellow A in Delaying Liver Aging.

Aging affects the structure and function of the liver. Hydroxysafflor yellow A (HSYA) effectively improves liver aging (LA) in mice, but the potential mechanisms require further exploration. In this study, an integrated approach combining network pharmacology and transcriptomics was used to elucidate the potential mechanisms of HSYA delay of LA. The targets of HSYA were predicted using the PharmMapper, SwissTargetPrediction, and CTD databases, and the targets of LA were collected from the GeneCards database. An ontology (GO) analysis and a Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotation of genes related to HSYA delay of LA were performed using the DAVID database, and Cytoscape software was used to construct an HSYA target pathway network. The BMKCloud platform was used to sequence mRNA from mouse liver tissue, screen differentially expressed genes (DEGs) that were altered by HSYA, and enrich their biological functions and signaling pathways through the OmicShare database. The results of the network pharmacology and transcriptomic analyses were combined. Then, quantitative real-time PCR (qRT-PCR) and Western blot experiments were used to further verify the prediction results. Finally, the interactions between HSYA and key targets were assessed by molecular docking. The results showed that 199 potentially targeted genes according to network pharmacology and 480 DEGs according to transcriptomics were involved in the effects of HSYA against LA. An integrated analysis revealed that four key targets, including HSP90AA1, ATP2A1, NOS1 and CRAT, as well as their three related pathways (the calcium signaling pathway, estrogen signaling pathway and cGMP-PKG signaling pathway), were closely related to the therapeutic effects of HSYA. A gene and protein expression analysis revealed that HSYA significantly inhibited the expressions of HSP90AA1, ATP2A1 and NOS1 in the liver tissue of aging mice. The molecular docking results showed that HSYA had high affinities with the HSP90AA1, ATP2A1 and NOS1 targets. Our data demonstrate that HSYA may delay LA in mice by inhibiting the expressions of HSP90AA1, ATP2A1 and NOS1 and regulating the calcium signaling pathway, the estrogen signaling pathway, and the cGMP-PKG signaling pathway.

[Spatiotemporal distribution and multi-source characteristics of microplastics in the soil and water environment of Poyang Lake Wetland, China]. / 鄱阳湖湿地水土环境中微塑料的时空分布及多源性.

The increasing microplastics (MPs) pollution in freshwater wetlands has received global concerns. To investigate the spatiotemporal dynamics of MPs in the wetlands of Poyang Lake, surface water and sediment samples were collected from five rivers entering the lake as well as the confluence of Poyang Lake into the Yangtze River, in both dry and wet seasons. The MPs in water and sediment were extracted by the digestion-filtration method and flotation-separation-digestion-filtration method, respectively. Light microscope, Fourier transform infrared spectroscopy, and scanning electron microscope were used for microplastic characterization. The results showed that the abundance of MPs ranged from 32.1 to 127.3 n·L-1 in water samples, and from 533.3 to 1286.6 n·kg-1 in sediment samples during the wet season. In the dry season, the abundance of MPs ranged from 87.1 to 295.5 n·L-1 in water and from 460.0 to 1368.0 n·kg-1 in sediment. Compared with other freshwater wetlands, Poyang Lake had higher abundance of MPs. There were temporal and spatial differences among regions. The main forms of MPs included beads, fragment, film and fiber, and the corresponding polymer components were mainly polystyrene, polypropy-lene and polyethylene. Beads (35.7% in wet season and 52.0% in dry season) were the main form of MPs in water, while fragment (45.8% in wet season and 69.7% in dry season) was the main form of MPs in sediment. Small size (<0.1 mm) MPs were dominant (>50%) in water and sediment in both seasons. The abundance of MPs with different sizes decreased with the increases of size. The potential main sources of MPs in the wetlands of Poyang Lake included the discharge of industrial wastewater, discharge from urban and rural domestic sewage treatment plants, agricultural and fishing activities, and improper disposal of domestic wastes.

Ginsenoside Rg1 ameliorates sepsis-induced acute kidney injury by inhibiting ferroptosis in renal tubular epithelial cells.

Acute kidney injury (AKI) represents a prevailing complication of sepsis, and its onset involves ferroptosis. Ginsenoside Rg1 exerts a positive effect on kidney diseases. This study explored the action of ginsenoside Rg1 in sepsis-induced AKI (SI-AKI) by regulating ferroptosis in renal tubular epithelial cells (TECs). Sepsis rat models were established using cecal ligation and puncture (CLP) and cell models were established by treating human renal TECs (HK-2) with LPS to induce ferroptosis. Serum creatinine (SCr) and blood urea nitrogen (BUN) and urine KIM1 contents in rats were determined by ELISA kits. Kidney tissues were subjected to immunohistochemical and H&E stainings. Iron concentration, malondialdehyde (MDA), glutathione (GSH), and ferroptosis-related protein (ferritin light chain [FTL], ferritin heavy chain [FTH], GSH peroxidase 4 [GPX4], and Ferroptosis suppressor protein 1 [FSP1]) levels in kidney tissues and HK-2 cells were measured using ELISA kits and Western blotting. HK-2 cell viability was detected by cell counting kit-8, and cell death was observed via propidium iodide staining. Reactive oxygen species accumulation in cells was detected using C11 BODIPY 581/591 as a molecular probe. In CLP rats, ginsenoside Rg1 reduced SCr, BUN, KIM1, and NGAL levels, thus palliating SI-AKI. Additionally, ginsenoside Rg1 decreased iron content, FTL, FTH, and MDA levels, and elevated GPX4, FSP1, and GSH levels, thereby inhibiting lipid peroxidation and ferroptosis. Moreover, FSP1 knockdown annulled the inhibition of ginsenoside Rg1 on ferroptosis. In vitro experiments, ginsenoside Rg1 raised HK-2 cell viability and lowered iron accumulation and lipid peroxidation during ferroptosis, and its antiferroptosis activity was dependent on FSP1. Ginsenoside Rg1 alleviates SI-AKI, possibly resulting from inhibition of ferroptosis in renal TECs through FSP1.

Identification and characterization of chemical and physical stability of insulin formulations utilizing degraded glycerol after repeated use and storage.

Insulin treatment is currently considered to be the main strategy for controlling diabetes. Although the recombinant insulin formulation is relatively mature, we found that a batch of insulin formulation exhibited an unusual degradation rate in the stability experiment. The main purposes of this article are to identify the root cause for this phenomenon and characterize of chemical and physical degradation products. We compared the chemical and physical stability of two batches of insulin formulations prepared separately with simulated repeated use and freshly opened glycerol. The chemical stability of insulin was identified by liquid chromatography coupled with tandem mass spectrometry (LC- MS/MS). Micro-flow imaging (MFI), far-ultraviolet circular dichroism (Far-UV CD) and Thioflavin T (ThT) fluorescent assays were used to reveal protein aggregation and fibrosis. The chemical and physical stability of the insulin formulation with newly opened glycerol was much better than that with degraded glycerol, and both groups of formulations were extremely sensitive to light. The results indicated that the original batch insulin formulation with abnormal stability was indeed caused by the excipient glycerol after long-term storage and repeated usage. More attention should be paid to the quality changes of excipients during repeated usage and storage of excipients for the practical purpose. Moreover, we have discovered a novel degradation pathway for insulin and peptides in general. In addition, LC-MS/MS results suggested that the N-terminus of insulin B-chain was prone to chemical degradation which enlightens that it could be potentially modified to improve the stability of insulin formulations.

Investigation of an Uncommon Artifact during Reducing Capillary Electrophoresis-Sodium Dodecyl Sulfate Analysis of a Monoclonal Antibody with Dynamic Light Scattering and Reversed Phase High-Performance Liquid Chromatography.

PURPOSES: In reducing capillary electrophoresis sodium dodecyl sulfate (CE-SDS) analysis of a monoclonal antibody (mAb-1), the peak area ratio of heavy chain (HC) to light chain (LC) was out of balance, while multiple artifact peaks were observed following the migration of HC. The main purposes of this study were to describe the techniques utilized to eliminate this artifact and clarify the root cause for this interesting phenomenon. METHODS: We optimized the CE-SDS analysis of mAb-1 by a vairety of techniques including changing the concentration of protein or replacing SDS with a more hydrophobic surfactant (i.e., sodium hexadecyl sulfate (SHS) or sodium tetradecyl sulfate (STS) instead of SDS) in sample and/or the sieving gel buffer. Dynamic light scattering (DLS) and reversed phase high-performance liquid chromatography (RP-HPLC) were used to study the protein-surfactant complex. RESULTS: The artifact could be partially mitigated by reducing the protein concentration and replacing SDS with SHS or STS in the sample and/or the sieving gel buffer solutions. Due to replacing a more hydrophobic surfactant, the HC-surfactant complex formed was more resistant to dissociation, preventing additional hydrophobic HC-HC interaction and aggregation, thus eliminating the artifact problem. CONCLUSIONS: DLS and RP-HPLC are powerful supplementary techniques in characterizing the protein-surfactant complex, and hydrophobic surfactants such as SHS and STS could afford more normal electropherograms during the analysis of mAbs.

[Effects of electron acceptor and light on the abundance of microbial function gene related to soil CH4 emission]. / ç”µå­å—ä½“å’Œå ‰ç §å¯¹åœŸå£¤CH4æŽ’æ”¾ç›¸å ³å¾®ç”Ÿç‰©åŠŸèƒ½åŸºå› ä¸°åº¦çš„å½±å“.

To explore the effects of different electron acceptors on soil methane emission and responses of soil microorganisms to different light conditions, a strict anaerobic 20-day incubation experiment was conducted with eight treatments: darkness + Fe3+ (DF); darkness + NO3- (DN); darkness +SO42- (DS); darkness + distilled water (DCK); light + Fe3+ (LF); light + NO3- (LN); light +SO42- (LS); light + distilled water (LCK). The changes of methane concentration in the anaerobic incubation flask and the variation of the abundance of bacteria, archaea, fungi and six soil functional genes were analyzed. Results showed that soil methane emission under NO3-, SO42- addition and control (CK) was significantly lower under light conditions than dark, except the Fe3+ treatment. DN, DCK and LF treatments had the highest abundance of bacteria, fungi and archaea genes, respectively. The gene abundance of methanogenic mcrA, sulfate-reducing bacteria Dsr, and carbon-fixing CbbL were significantly up-regulated in the LF, while that of methanotrophs pmoA, iron-reducing bacteria Geo, and denitrifying bacteria nosZ were significantly up-regulated in the LN, DCK and LCK, respectively. Results of Pearson correlation and RDA analysis showed that CH4 emission was significantly positively correlated with CO2 concentration, pH, ammonium-nitrogen, and total N contents, and negatively correlated with N2O concentration, Eh, nitrate, and total C contents. Under dark condition, methane emission was positively correlated with archaea and pmoA genes abundance, and negatively correlated with other genes abundance. Under light condition, methane emission was negatively correlated with the abundance of soil microbe and functional genes. In general, methane emission under light condition was significantly lower than that under dark condition (except for the Fe3+ treatment). These results showed that it was helpful to reduce methane emission under light condition, but the increase or decrease of methane emission was closely related to the type of electron acceptors and the functional responses of soil micro-organisms.

Freeze-Dried Biopharmaceutical Formulations are Surprisingly Less Stable than Liquid Formulations during Dropping.

PURPOSES: This article describes an interesting phenomenon in which optimized freeze-dried (FD) biopharmaceutical formulations are generally more prone to degradation than their liquid counterparts during dropping and proposes an underlying cause for this surprising phenomenon. METHODS: Two monoclonal antibodies (mAbs) and a fusion protein (FP) were used as model biopharmaceuticals. The stability after dropping stress was determined by ultraviolet-visible (UV-Vis), size exclusion high-performance liquid chromatography (SE-HPLC), micro-flow imaging (MFI), and dynamic light scattering (DLS). RESULTS: Contrary to what we would normally assume, the FD formulations of the three biopharmaceuticals studied here generally showed much higher amounts of protein sub-visible particles (SbVPs) than liquid formulations after applying the same dropping stress as determined by MFI and DLS. Traditional techniques, such as UV-Vis and SE-HPLC, could hardly detect such degradation. CONCLUSIONS: We propose that the higher temperature caused by dropping for the FD powders than the liquid formulations was probably one of the root causes for the higher amount of particles formed for the FD powders. We also recommend that dropping stress should be included for early-stage screening and choosing liquid versus FD biopharmaceutical formulations.

[Microbial Community Structure on Microplastic Surface in the Grus leucogeranus Reserve of Poyang Lake].

As a new type of pollutant, microplastics have attracted increasing attention. Microplastics in aquatic ecosystems are accumulating at an unprecedented scale, causing significant environmental and economic impacts. In this study, sediments and different types of microplastic samples were collected from the Grus leucogeranus Reserve of Wuxing Reclamation Farm of Poyang Lake, which is the largest freshwater lake in China. The main types of microplastics were film (PE), debris (PP1), fiber (PP2), and foam (PS), and the polymers were identified as polyethylene, polypropylene, and polystyrene in the study area. The structures of microbial communities (fungi and bacteria) were identified using 16S high-throughput sequencing. The results showed that there was no significant difference in the Ace and Chao of bacteria between the surface of PE and PP1 and that of the surrounding sediments (P>0.05), whereas PP2 and PS were significantly lower than those in surrounding sediments (P<0.05). Ace and Chao of fungi showed that PE and PS had no significant differences with the sediment (P>0.05), and PP1 and PP2 were significantly lower than those in surrounding sediments (P<0.05). The species diversity Shannon and Simpson index of bacteria and fungi on different types of microplastic surfaces were lower than that of sediment. The bacterial communities on the sediment and microplastic surface mainly included Proteobacteria and Bacteroidetes. In the fungal community, Basidiomycota, Ascomycota, and Chytridiomycota were the dominant bacteria. Through KEGG functional prediction, it was found that most of the metabolic pathways with a significant difference between bacteria and sediments on the surface of microplastics and with an abundance ratio higher than 1% were related to metabolism. Compared with that of sediment, the metabolic pathways of PE and PP2 on microplastic surfaces were down-regulated mainly in cell motility, signal transduction, and carbohydrate metabolism, whereas the energy metabolism, general and global metabolism pathways, and cofactor metabolism were up-regulated. Compared with that of sediment, the bacterial metabolic pathways of PS and PP1 on microplastic surfaces were down-regulated, mainly including general and global metabolic pathways, translation, and exogenous biodegradation, and cell motility and signal transduction were up-regulated. However, the abundance of other functional genes in sediments and microplastic samples showed little difference. The results indicated that microplastics can change the structure of microbial communities, and the microbial community on the surface of microplastics could catalyze metabolic reactions and promote the decomposition of microplastics. The study of microplastic surface microbial structure in Poyang Lake can support management decisions to protect the ecological integrity of the lake.

Characterization of Grinding-Induced Subvisible Particles and Free Radicals in a Freeze-Dried Monoclonal Antibody Formulation.

PURPOSES: The primary objectives of this study were to investigate the degradation mechanisms of freeze-dried monoclonal antibody (mAb) formulations under mechanical grinding, assess the sensitivity and suitability of various particle analysis techniques, analyze the structure of the collected subvisible particles (SbVPs), and analyze the antioxidant mechanism of methionine (Met) under degradation process to gain a thorough understanding of the phenomenon. METHODS: The freeze-dried mAb-X formulations underwent grinding, and the resultant SbVPs were characterized through visual inspection, flow imaging microscopy, dynamic light scattering, ultraviolet-visible spectroscopy, and size-exclusion high-performance liquid chromatography. We further evaluated the effect of different temperatures and the free radical scavenger Met on SbVP formation. The produced free radicals were detected using electron paramagnetic resonance, and Met S-oxide formation was detected using liquid chromatography-mass spectrometry. In addition, we analyzed the obtained SbVPs using capillary electrophoresis sodium dodecyl sulfate and Fourier transform infrared spectroscopy. RESULTS: Grinding leads to SbVP formation under high temperature and free radical formation. Free radicals produced during grinding require the participation of a macromolecule. Met could then bind to the produced free radicals, thus partially protecting mAb-X from degradation while itself undergoing oxidation to form Met(O). Sensitivity differences between different particle analysis techniques were evaluated, and the obtained SbVPs showed significant changes in secondary structure and the formation of covalent aggregates and fragments. CONCLUSIONS: Met plays the role of an antioxidant in protecting macromolecules by quenching the free radicals produced during grinding. To thoroughly characterize SbVPs, multiple and orthogonal particle analysis techniques should be used, and if necessary, SbVPs should be processed by enrichment to accurately analyze primary and high order structures.