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Nylon-6,6 microplastics (NMPs) in aquatic systems have emerged as potential contaminants to the global environment and have garnered immense consideration over the years. Unfortunately, there is currently no efficient method available to eliminate NMPs from sewage. This study aims to address this issue by isolating Brucella intermedia ZL-06, a bacterium capable of producing a bacterial polysaccharide-based flocculant (PBF). The PBF generated from this bacterium shows promising efficacy in effectively flocculating NMPs. Subsequently, the precipitated flocs (NMPs + PBF) were utilized as sustainable feedstock for synthesizing PBF. The study yielded 6.91 g/L PBF under optimum conditions. Genome sequencing analysis was conducted to study the mechanisms of PBF synthesis and nylon-6,6 degradation. The PBF exhibited impressive flocculating capacity of 90.1 mg/g of PBF when applied to 0.01 mm NMPs, aided by the presence of Ca 2+ . FTIR and XPS analysis showed the presence of hydroxyl, carboxyl, and amine groups in PBF. The flocculation performance of PBF conformed to Langmuir isotherm and pseudo-first-order adsorption kinetics model. These findings present a promising approach for reducing the production costs of PBF by utilizing NMPs as sustainable nutrient sources., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Recalcitrant dissolved organic carbon (RDOC) resulting from microbial carbon (MCPs) holds promise as a relatively long-term natural carbon sink in marine environments. However, the RDOC formation mechanism remains uncertain in terrestrial aquatic systems. To determine the microbial impacts on autochthonous dissolved organic carbon (DOC), RDOC formation, and the critical influencing bacteria species, spatial changes in hydrochemistry, carbon isotopes, and microbial diversity were investigated in water samples from the karstic Lijiang River, southwest China. Samples were collected at various locations along the river system in May and July 2017. The biodegradable DOC (BDOC), RDOC, soil sourced DOC (SDOC), submerged aquatic vascular plant sourced DOC (PDOC) and microbial sourced DOC (MDOC) were calculated using the in-situ microbial incubation method, stable carbon isotopes and C/N ratio. RDOC accounted for 67% to 93% of DOC concentrations, measuring 1.3 mg/L and 1.2 mg/L in May and July, respectively. In May, BDOC concentrations increased by 0.05 mg/L from 0.18 mg/L to 0.23 mg/L, but decreased by 0.43 mg/L from 0.66 mg/L to 0.23 mg/L in July. The spatiotemporal variation of BDOC indicated photosynthesis was the main BDOC source and induced high autochthonous DOC formation, especially in May. However, RDOC was the dominant accumulation component in Lijiang River. MDOC increased by 0.86 mg/L from 0 to 0.86 mg/L in May and 0.78 mg/L from 0.10 mg/L to 0.88 mg/L in July, which was the dominant accumulated DOC and RDOC component. The abundance of Sporichthyaceae accounted for 3.4%-22.6% in May and Novosphingobium accounted for 3.5%-34.0% in July. These were the critical bacteria species induced MDOC formation, which were confirmed by their abundances in KEGG pathway modules determined by PICRUAST2. These results demonstrate that heterotrophic bacteria dominate autochthonous DOC and RDOC formation in the karst surface river, which is valuable for understanding organic carbon cycling in karstic aquatic systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Human interventions such as tunnel construction have caused groundwater depletion, which substantially affected the functions of forest tree species and their communities. However, the extent to which tunneling-induced groundwater depletion (TIGD) degrades their function levels at various spatial-temporal scales under varying climate conditions remains still unclear. Researchers used stand-scale dendrological records to track and extract the effects of TIGD associated with a single or series of tunneling events (three tunneling events during 1999-2001, 2006-2008, and 2010-2013) on short- and long-term growth levels of two dominant drought-tolerant tree species across (karst and non-karst) landscapes affected by tunnel construction and landscapes not subjected to tunnel construction in a mountainous forest ecosystem located in the southwest of China. The results showed that growth responses of both trees stand to TIGD, and the TIGD-linked water losses of other available water sources were negative and widespread across tunnel-affected landscapes, particularly in the karst landscapes known as delicate landscapes. Tree stands with faster (more vigorous) growth rates showed more significant adverse growth levels in response to either tunneling-induced or drought-induced water stresses. Also, they showed the highest recovered growth levels in response to favorable climatic conditions. Moreover, the growth level in the tunnel-affected forest never fully recovered during six years of very wet weather (2012-2018) after the construction of the final (third) tunnel in 2010-2013. Current research shows that tunnel construction has a cumulatively detrimental impact on the long-term survival of the forest. Even with the mediation of long-term very wet circumstances, it can substantially restrict the development dynamics of the forest compared to drought., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: There is controversy about whether the amniotic fluid contains bacteria. With the use of sequencing-based methods, recent studies report that the amniotic fluid is colonized by microorganisms. However, background-contaminating DNA might lead to false-positive findings when such a low microbial biomass sample is examined., Objective: The purpose of this study was to determine whether the midtrimester amniotic fluid of patients who subsequently had normal pregnancy outcomes contains a microbial signature., Study Design: In this prospective cohort study, 42 amniotic fluid samples were collected from 37 pregnancies (5 twin and 32 singletons) during genetic amniocentesis in the midtrimester. The subsequent pregnancy outcomes of all the participants were followed. Multiple methods were used to detect the presence of microorganisms in this study, which included cultivation, quantitative real-time polymerase chain reaction, and 16S ribosomal RNA gene sequencing. Multiple positive control samples (n=16) served as quality control samples and included 3 adult fecal samples, 4 vaginal swabs, and 9 artificial bacterial communities that were run in parallel with negative control samples (n=12) that included 4 samples from the hospital operating room and 8 samples from the laboratory, to account for background-contaminating DNA during each step of the experiments., Results: No bacteria under anaerobic or aerobic conditions or genital mycoplasmas were cultured from any of the amniotic fluid samples. Quantitative polymerase chain reaction did not reveal greater copy numbers of 16S ribosomal RNA gene in amniotic fluid samples than in negative control samples. 16S Ribosomal RNA gene sequencing did not indicate a significant difference in the microbial richness or community structures between amniotic fluid and negative control samples., Conclusion: With multiple methods of microbiologic inquiry, no microorganisms were identified in the midtrimester amniotic fluid of healthy pregnancies with a normal pregnancy outcome., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Bioflocculants are widely used in a large variety of applications, because of their wide range of flocculation. There is limited information in the literature about the ability of bioflocculants to perform beneficial functions without having adverse effects on blood components. In this study, general hemocompatibility of a bioflocculant (MBF-06) was investigated in an in vitro system, measuring flocculation of plasma proteins, red blood cell integrity, blood cell counts, platelet activation, clot formation, complement activation, cytotoxicity and inflammatory response. Effects of MBF-06 included low plasma protein flocculation, low platelet activation, low inflammatory response, no hemolysis or cytotoxicity and increased expression of coagulation markers, including prothrombin fragments 1+2. These findings suggested that the rapid hemostasis caused by MBF-06 resulted, essentially, from humoral coagulation. Overall, our observations revealed the great potential of MBF-06 as a novel hemostatic agent., (Copyright © 2017 Elsevier B.V. All rights reserved.)