Thrombotic events and prophylactic anticoagulation in pediatric patients with COVID-19: a systematic review and meta-analysis.

BACKGROUND: Venous thromboembolism (VTE) can occur in children with COVID-19, and the efficacy and safety of prophylactic anticoagulant therapy are uncertain. This study aimed to assess the incidence of VTE in pediatric patients with COVID-19, the association of D-dimer with thrombus formation, and the effectiveness and safety of prophylactic anticoagulation treatment. METHODS: We systematically searched databases from January 2020 to February 2023. A systematic review and meta-analysis were conducted to determine the incidence of VTE in children and evaluate the efficacy and safety of prophylactic anticoagulant therapy. RESULTS: Thirteen cohort studies and one clinical trial were included. The pooled incidence rate of VTE in affected children was 1.5% (95% CI 0.4-2.9%). Children with D-dimer levels five times higher than normal had a higher risk of VTE (OR 4.92, 95% CI 1.60-15.11). Prophylactic anticoagulant therapy did not significantly reduce the risk of VTE (OR 1.35, 95% CI 0.74-2.49). The safety of prophylactic anticoagulant therapy was relatively high, with major bleeding and all-cause mortality rates below 0.1% (95% CI 0.0-0.2%). CONCLUSIONS: The incidence of VTE in children with COVID-19 is low, and prophylaxis based on ISTH standards is reasonable. Low-molecular-weight heparin (LMWH) for VTE prevention has a high level of safety. However, more high-quality studies are needed to understand the impact of anticoagulant therapy on VTE incidence in pediatric patients with COVID-19.

Relic DNA effects on the estimates of bacterial community composition and taxa dynamics in soil.

DNA-based analyses have become routine methods in soil microbial research, for their high throughput and resolution in characterizing microbial communities. Yet, concerns arise regarding the interference of relic DNA in estimates of viable bacterial community composition and individual taxa dynamics in soils that recovered from post-gamma irradiation. In this study, different soil samples with varying bacterial diversity but similar soil properties were randomly selected. We split each sample into two parts: one part was treated with propidium monoazide (PMA) before DNA extraction, PMA can bind to relic DNA and inhibit PCR amplification by chemical modification; DNA of the other part was extracted following the same process but without PMA pretreatment. Then, soil bacterial abundance was quantified by quantitative polymerase chain reaction, and bacterial community structure was examined by Illumina metabarcoding sequencing of 16S rRNA gene. The results showed that the higher bacterial richness and evenness were estimated when relic DNA was present. The variation trends of bacterial abundance, alpha diversity, and beta diversity remained the same, as reflected by the significant correlations between PMA-treated and -untreated samples (P < 0.05). Moreover, as the mean abundance increased, the reproducibility of detecting individual taxa dynamics between relic DNA present and absent treatments increased. These findings provide empirical evidence that a more even distribution of species abundance derived from relic DNA would result in the overestimation of richness in the total DNA pools and also have crucial implications for guiding proper application of high-throughput sequencing to estimate bacterial community diversity and taxonomic population dynamic. KEY POINTS: • Relic DNA effects on the bacterial community in sterilized soils were assessed. • More even species abundance distribution in relic DNA overestimates true richness. • The reproducibility of individual taxa dynamics increased with their abundance.

Stronger linkage of diversity-carbon decomposition for rare rather than abundant bacteria in woodland soils.

Soil microbial diversity is important for maintaining ecosystem functions. However, the linkage between microbial diversity, especially rare and abundant bacterial diversity, and carbon decomposition remains largely unknown. In this study, we assessed the establishment and maintenance of rare and abundant bacterial α-diversities at the taxonomic and phylogenetic levels and their linkages with soil carbon decomposition separately in four Chinese woodlands. Compared to abundant bacteria, rare bacteria showed higher community diversity, tighter phylogenetic clustering, wider environmental breadth, stronger phylogenetic signals, and higher functional redundancy. The assembly of the abundant bacterial subcommunity was governed by stochastic (59.2%) and deterministic (41.8%) processes, whereas the assembly of the rare bacterial subcommunity was mainly dominated by deterministic processes (85.8%). Furthermore, total phosphorus, soil pH, and ammonium nitrogen balanced stochastic and deterministic processes in both rare and abundant bacterial subcommunities. Our results reveal that rare bacteria displayed stronger environmental adaptability and environmental constraint. Importantly, the α-diversities of rare taxa, rather than abundant taxa, were significantly related to carbon decomposition. This study provides a holistic understanding of biogeographic patterns of abundant and rare bacteria and their α-diversities in relation to carbon decomposition, thus helping us better predict and regulate carbon dynamics under the background of global climate change.

Xuanfei Pingchuan Capsules Ameliorate Autophagy in Human Bronchial Epithelial Cells by Inhibiting p38 Phosphorylation.

Background: This study aimed to investigate the protective effect of Xuanfei Pingchuan Capsules (XFPC) on autophagy and p38 phosphorylation in human bronchial epithelial (HBE) cells induced by cigarette smoke extract (CSE). Methods: HBE cells were divided into five groups: blank, CSE, low XFPC dose (XFPC-L), medium XFPC dose (XFPC-M), and high XFPC dose (XFPC-H). HBE cells were induced by CSE to establish a cell model for chronic obstructive pulmonary disease, and different doses of XFPC medicated serum were used to treat the cells. The Cell Counting Kit-8 was used to detect cell viability. Flow cytometry was used to detect cell apoptosis. Fluorescence microscopy and the expression level of microtubule-associated protein light chain 3 (LC3)-II in immunohistochemical method were used to observe autophagy in cells. Western blot was used to detect the protein expression level of p38, phospho-p38 (p-p38), LC3-I, LC3-II and Beclin 1. Real-time polymerase chain reaction was used to detect the expression of LC3-I, LC3-II and Beclin 1 on mRNA level. Results: Compared with the blank group, the cell viability of the CSE group was significantly decreased, and apoptosis and the level of autophagy in cells were significantly increased. The mRNA and protein expression of LC3-I, LC3-II, Beclin 1 and the protein level of p-p38 were significantly increased in the CSE-HBE cells. Compared to the CSE group, the different doses of XFPC medicated serum increased cell viability, decreased cell apoptosis, and inhibited mRNA and protein expression of LC3-I, LC3-II, Beclin 1 and protein level of p-p38. These results were especially observed in the group XFPC-H. After adding a p38 agonist, the therapeutic effect of XFPC on cell viability and autophagy was suppressed. Conclusion: XFPC significantly increased cell viability in a CSE-induced HBE cell model for chronic obstructive pulmonary disease through inhibiting the level of autophagy mediated by phosphorylation of p38.

Temporal Changes in the Function of Bacterial Assemblages Associated With Decomposing Earthworms.

Soil invertebrate corpse decomposition is an ecologically significant, yet poorly understood, process affecting nutrient biogeochemical cycling in terrestrial ecosystems. Here, we attempted to answer how the substrate chemistry and microbial community change during soil invertebrate (earthworm) decomposition and what roles microbes play in this process. Specifically, the dead earthworms (Amynthas corticis) were buried in two soils where the earthworms inhabited, or not, until more than 50% of the earthworm mass was lost. For both soils, earthworms decomposed faster during the early stage (between 0 and 3 days), as reflected by the higher rate of decomposition and increased accumulation of dissolved organic matter (DOM). This decomposition pattern was paralleled by bacterial community dynamics, where bacterial richness and diversity were significantly higher during early decomposition (p < 0.05) with the relative abundances of many genera decreasing as decomposition progressed. The succession of the bacterial community composition was significantly correlated with time-course changes in DOM composition (p < 0.05). Particularly, more functional groups (e.g., microbes associated with carbon, nitrogen, and sulfur cycling) were identified to be linked with the change of a specific DOM type during the early decomposition phase. By exploring the ecologically important process of soil invertebrate decomposition and its associated bacterial communities, this study provides evidence, e.g., a statistically significant positive correlation between bacterial community and DOM compositions, which supports the widely recognized yet less-tested microbial community structure-function relationship hypothesis in invertebrate decomposition.

Plant evenness modulates the effect of plant richness on soil bacterial diversity.

Understanding the relationships between aboveground and belowground biodiversity will help to expand our knowledge on how ecological communities and processes are interactively determined, and thus provide new perspectives for the conservation of biodiversity. Despite the theoretical analyses generally predicting a positive relationship between plant richness and soil microbial diversity, the results from empirical studies have been mixed, probably due to the effect of plant evenness. To investigate this relationship, we conducted field experiments in two geographically distinct sites (Linhai and Shenmu, >1400km apart), by simultaneously manipulating plant richness (2, 4, and 8 species) and evenness (homogeneous versus non-homogeneous). After one year, the bacterial response to plant richness with different plant evenness levels was evaluated using terminal restriction fragment length polymorphism (T-RFLP) analysis. Our results showed that plant evenness modulated plant richness effects on bacterial community, as reflected by the more pronounced positive correlations between bacterial richness and plant richness in homogeneous plant community than in the non-homogeneous treatment. Additionally, plant community structure significantly affected bacterial communities only in the homogeneous treatment in Shenmu, but not in the non-homogeneous treatments. Our results demonstrate that plant evenness could regulate plant richness effects on bacterial alpha- and beta-diversity and thus provide valuable insights into the association between aboveground and belowground biodiversity.

Carbonaceous Nanomaterials Have Higher Effects on Soybean Rhizosphere Prokaryotic Communities During the Reproductive Growth Phase than During Vegetative Growth.

Carbonaceous nanomaterials (CNMs) can affect agricultural soil prokaryotic communities, but how the effects vary with the crop growth stage is unknown. To investigate this, soybean plants were cultivated in soils amended with 0, 0.1, 100, or 1000 mg kg-1 of carbon black, multiwalled carbon nanotubes (MWCNTs), or graphene. Soil prokaryotic communities were analyzed by Illumina sequencing at day 0 and at the soybean vegetative and reproductive stages. The sequencing data were functionally annotated using the functional annotation of prokaryotic taxa (FAPROTAX) database. The prokaryotic communities were unaffected at day 0 and were altered at the plant vegetative stage only by 0.1 mg kg-1 MWCNTs. However, at the reproductive stage, when pods were filling, most treatments (except 1000 mg kg-1 MWCNTs) altered the prokaryotic community composition, including functional groups associated with C, N, and S cycling. The lower doses of CNMs, which were previously shown to be less agglomerated and thus more bioavailable in soil relative to the higher doses, were more effective toward both overall communities and individual functional groups. Taken together, prokaryotic communities in the soybean rhizosphere can be significantly phylogenetically and functionally altered in response to bioavailable CNMs, especially when soybean plants are actively directing resources to seed production.