Incomplete recovery of gut microbiota in marine medaka (Oryzias melastigma) during the depuration phase, after exposure to sulfamethazine/nanoplastics.

The persistence of antibiotics and nanoplastics in aquatic environment poses a great threat to aquatic organisms. In our previous study, significant decreases of bacterial richness and changes of bacterial communities in the Oryzias melastigma gut after sulfamethazine (SMZ) and polystyrene nanoplastics (PS) exposure were observed. Here, the O. melastigma dietary exposed to SMZ (0.5 mg/g, LSMZ; 5 mg/g, HSMZ), PS (5 mg/g, PS) or PS + HSMZ were depurated for 21 days to assess the extent of which these effects were reversible. Our results revealed that most diversity indexes of bacterial microbiota in the O. melastigma gut from the treatment groups were insignificantly different from the control, suggesting a large recovery of bacterial richness. Although the sequence abundances of a few genera remained significantly changed, the proportion of dominant genus was recovered. Exposure to SMZ affected the complexity of the bacterial networks, and the cooperation and exchange events of positively associated bacteria were enhanced during this period. After depuration, increases in the complexity of networks and intense competitions among bacteria were observed, which was beneficial for the robustness of networks. However, the gut bacterial microbiota was less stable, and several functional pathways were dysregulated, relative to the control. In addition, higher occurrence of pathogenic bacteria was found in the PS + HSMZ group relative to the signal pollutant group after depuration, indicating a greater hazard for the mixture of PS and SMZ. Taken together, this study contributes to a better understanding of the recovery of bacterial microbiota in fish gut after individual and combined exposure to nanoplastics and antibiotics.

Effects of rhubarb peony decoction combined with antibiotics in treating pediatric periappendiceal abscess.

Background/purpose: Rhubarb peony decoction (RPD) is a formula of traditional Chinese medicine that has been widely used to treat intra-abdominal inflammatory diseases. To investigate the therapeutic efficacy of RPD in pediatric periappendiceal abscess, patients who received intravenous antibiotics alone were compared with those treated with intravenous antibiotics combined with RPD. Methods: A retrospective review of children with periappendiceal abscess who received conservative treatment in our hospital between January 2013 and April 2022 was performed. The patients were divided into an intravenous antibiotic group (the control group) and an intravenous antibiotic combined with RPD group (the intervention group). Interval appendectomy (IA) was generally performed 10-12 weeks after conservative treatment. The primary outcome was the cure rate of conservative treatment, while the secondary outcomes included the recurrence rate, days of total intravenous antibiotic use, length of hospital stay (LOS), postoperative complications, and liver injury caused by RPD. Results: A total of 142 patients (77 girls and 65 boys) were included, 52 in the control group and 90 in the intervention group. The two groups were similar in demographic data and clinical characteristics (P > 0.05). The mean total course of RPD in the intervention group was 11.82 days. The intervention group had a significantly higher cure rate than the control group (93.33% vs. 80.77%, P = 0.029), and the length of total intravenous antibiotic use (P = 0.150), LOS (P = 0.077), recurrence rate (9.52% vs. 4.76%, P = 0.439), as well as the operation time (P = 0.101), LOS (P = 0.572), and postoperative complications (P = 0.549) were not significantly different between the two groups when the patients received IA. No patient had a liver injury caused by RPD during the treatment. Conclusion: Intravenous antibiotics combined with RPD demonstrated high effectiveness and safety for treating pediatric periappendiceal abscess.

Feedback mechanisms of periphytic biofilms to ZnO nanoparticles toxicity at different phosphorus levels.

The increasing use of nanoparticles (NPs) has raised concerns about their potential environmental risks. Many researches on NPs focused on the toxicity mechanism to microorganisms, but neglect the toxicity effects in relation to nutritional conditions. Here, we evaluated the interactive effects of zinc oxide (ZnO) NPs and phosphorus (P) levels on the bacterial community and functioning of periphytic biofilms. Results showed that long-term exposure to ZnO NPs significantly reduced alkaline phosphatase activity (APA) of periphytic biofilms just in P-limited conditions. Co-occurrence network analysis indicated that ZnO NPs exposure reduced network complexity between bacterial taxa in P-limited conditions, while the opposite trend was observed in P-replete conditions. Correlation analysis and random forest modeling suggested that excessive Zn2+ released and high reactive oxygen species (ROS) production might be mainly responsible for the inhibition of APA induced by ZnO NPs under P-limited conditions, while adjustment of bacterial diversity and improvement of keystone taxa cooperation were the main mechanisms in maintaining APA when subjected to weak toxicity of ZnO NPs in P-replete conditions. Taken together, our results provide insights into the biological feedback mechanism involved in ZnO NPs exposure on the ecological function of periphytic biofilms in different P nutritional conditions.

Periphyton has the potential to increase phosphorus use efficiency in paddy fields.

The phosphorus (P) supply is mismatched with rice demand in the early and late stages of rice growth, which primarily results in low P use efficiency and high environmental risk. In recent years, the use of the natural periphyton in nutrient regulation in paddy fields has attracted much research interest. However, a mechanistic understanding of the action of periphyton on P biogeochemical cycling during the pivotal stages of rice growth has received little attention. In this study, the influence of periphyton proliferation on the soil surface and its consequential decomposition on P migration and bioavailability were investigated in two paddy soils using two microcosm experiments. The results showed that periphyton rapidly accumulated fertilizer P when it proliferated on the soil surface under favorable light condition, which led to more fertilizer P being stored on the soil surface and less P being fixed by soil particles or transported via runoff into the water bodies. The decomposition of periphyton under unfavorable light condition not only increased soil soluble reactive P, but also increased the amount of easily available P species, such as labile P, AlP, FeP, and mobilized OP. Thus, periphyton colonizing the soil surface in the early stage of rice growth could act as a P sink and decrease the P environmental risk, and its decomposition in the late stage of rice growth could act as a P source and activator. Phosphorus bioavailability regulated by periphyton could be synchronous with rice needs. Thus, periphyton has the potential to increase P use efficiency in paddy fields.

Determination of mercury and selenium in herbal medicines and hair by using a nanometer TiO2-coated quartz tube atomizer and hydride generation atomic absorption spectrometry.

The nanometer TiO(2) particle was coated onto the inner wall of a T-shaped quartz tube atomizer (QTA) and then was used as a new atomizer (NT-QTA) for the determination of Hg and Se by hydride generation atomic absorption spectrometry (HGAAS). After coating 67.4 mg TiO(2) on a quartz tube, the analytical performance of NT-QTA-HGAAS was compared to conventional QTA-HGAAS and it was improved as follows: (a) the linear range of the calibration curves was expanded from 10.0-80.0 ng mL(-1) to 5.0-150.0 ng mL(-1) for Hg, and from 10.0-70.0 ng mL(-1) to 5.0-100.0 ng mL(-1) for Se; (b) the characteristic concentration of was decreased from 2.8 ng mL(-1)/1% to 1.1 ng mL(-1)/1% for Hg and from 1.2 ng mL(-1)/1% to 0.8 ng mL(-1)/1% for Se; and (c) the interference from the coexistence of As on the determination of Hg and Se could be eliminated. The achieved technique was applied for the determination of Hg and Se in herbal medicines and hair.