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Highlights: [•] Bacterial growth and its gene/protein expression were detected at various concentrations of NaF. [•] Fluoride has a classic rise/fall response of inducing E. coli-GFPuv growth and gene and protein expression of GFPuv at 1mM. [•] The effect of fluoride on bacterial growth may be from regulation of mRNA expression. [•] Excessive fluoride may inhibit bacterial growth and/or disrupt its microbial balance in GI tract. [ABSTRACT FROM AUTHOR]

Thiacloprid is a neonicotinoid insecticide used to control sucking and chewing insects of fruits and vegetables. Hydrolysis, photolysis of thiacloprid in aqueous solutions, and soil degradation of three typical types of soil in China were studied. UHPLC-QTOF/MS was used to acquire high-resolution mass spectrometry information of thiacloprid's degradation products in water and soil samples, and the UNIFI platform with integrated data processing function was used to find and identify degradation products. The degradation kinetics of thiacloprid was determined. Six transformation products (M271, M287, M269, M295, M279, M267) were found after the data processing workflow in the UNIFI platform by using the raw MSE data. The structure of putative transformation products can be inferred based on the accurate mass of fragment ions and the automated spectral interpretation tools in the UNIFI platform. The structure of M271 was validated to be thiacloprid amide by comparing the ESI-MS2 fragment ions in soil samples and thiacloprid amide standard. The TrendPlot function of UNIFI was used to demonstrate the kinetics of the transformation products. Reduction, hydrolysis, oxidation are the main reactions of thiacloprid in three tested soil in China and buffer solutions. This study provided a reference for the rapid identification of the transformation products of other pesticides in specific environmental conditions. • Six degradation products of thiacloprid were identified using UHPLC-QTOF-MS. • Established a rapid identification method of the degradation products of thiacloprid. • This technique can be used for degradants analysis of other environmental pesticide. [ABSTRACT FROM AUTHOR]

Thifluzamide as a fungicide is toxic to brain of zebrafish embryos. Brain can regulate biological rhythms. To clarify whether thifluzamide would influence circadian rhythms, zebrafish embryos were treated with thifluzamide (0, 0.19, 1.90 and 2.85 mg/L) for 4 days. Exposure to thifluzamide induced pronounced changes in embryo brain and melatonin levels. The mRNA levels of genes related to circadian rhythms were apparently altered. Among these, the transcripts of cry1ba and clock1 were extremely correlated with exposure concentrations. Importantly, the content of cry1 showed no apparent changes, but the clock level was dramatically increased. Moreover, consistent with the inhibition of development and behavior, the levels of GH and DA were significantly inhibited. In addition, the expression levels of genes related to development, behavior and reproduction were significantly changed by thifluzamide. Therefore, we speculated that circadian disruption due to thifluzamide exposure were primarily attributed to increases in expression of clock1a and contents of clock, which might be at least in part responsible for abnormal development and behavior of zebrafish. In addition, our research will provide important insights into the grouped assessment of SDHI pesticides in future. • Thifluzamide induced brain damage in zebrafish embryo. • Thifluzamide inhibited development and behavior of zebrafish. • Thifluzamide enhanced the MT contents. • Thifluzamide enhanced the clock contents. • Thifluzamide upregulated the expression level of clock1a. Increased clock expression is responsible for dysregulation of circadian rhythm in zebrafish. [ABSTRACT FROM AUTHOR]

Circadian rhythms are fundamental to behavior and physiology of organisms. Flutolanil as a fungicide is toxic to zebrafish embryos. The aims of this study were to determine whether flutolanil would influence circadian rhythms of zebrafish and the mechanism involved. Zebrafish embryos were exposed to flutolanil (0, 0.125, 0.5 and 2 mg/L) for 4 days. Here we report that flutolanil increased the melatonin levels of zebrafish. The mRNA levels of genes related to circadian rhythms were significantly altered. The clock level was significantly increased, but the content of cry1 showed no apparent changes. Moreover, our findings that the level of GH was significantly decreased were consistent with the abnormal development of zebrafish embryos. The expression levels of genes related to development, behavior and reproduction were significantly altered by flutolanil. These results indicate that flutolanil disturbed circadian rhythms of zebrafish primarily by affecting the positive elements, which were at least in partial responsible for abnormal development and behavior of zebrafish. And we speculate that flutolanil is toxic to zebrafish embryos at least in part via dysregulation of circadian rhythms involving clock. • Flutolanil induced abnormal development and behavior of zebrafish. • Flutolanil significantly enhanced the MT contents. • Flutolanil significantly up-regulated the clock contents. • Flutolanil altered the expression levels of the positive genes. [ABSTRACT FROM AUTHOR]

Abstract Although previous trials have indicated that thifluzamide induces developmental inhibition in zebrafish, understanding the distinct mechanism of thifluzamide in this process remains challenging. This study investigated the effect of thifluzamide on zebrafish development and the underlying related signaling pathway. Thifluzamide repressed glucagon (GC) levels but increased growth hormone (GH) levels, and changed the expression of the genes related to growth and development. Additionally, protein kinase A (PKA) and leptin levels were obviously decreased in zebrafish after exposure to thifluzamide for 28 days, but the phosphorylation of cAMP responsive element-binding protein (CREB) was increased. Our results suggested that the anti-developmental effects of thifluzamide in zebrafish are largely associated with alterations in expressions of genes related to growth and development through modulation of leptin. Graphical abstract Image 1 Highlights • Thifluzamide significantly altered the expression of genes related to development. • The PKA level was significantly decreased in zebrafish exposed to thifluzamide. • The level of P-CREB was obviously enhanced by thifluzamide in zebrafish. • The level of leptin was apparently inhibited by thifluzamide. [ABSTRACT FROM AUTHOR]

Biochars can significantly sorb pesticides, and reduce their bioavailability in agricultural soils. In this study, the effects of a type of biochar (BC500) on the sorption, degradation, bioaccumulation and bioavailability of thiacloprid, which is a commonly used insecticide, were investigated. The thiacloprid sorption constant ( K f values) increased by 14 times after 2% BC500 application, and the degradation of the insecticide decreased with increasing amounts of the biochars in the soil. Coupled with the exhaustive extraction and single-point Tenax method, the bioavailability of thiacloprid was predicted in the presence of the biochar. In soils amended with BC500, the thiacloprid concentrations accumulated in Tenax correlated well with those observed in earthworms (R 2 = 0.887), whereas the concentrations extracted by exhaustive method followed a less significant relationship with those in earthworms (R 2 = 0.624). The results of Tenax extractions and earthworm bioassays indicate that biochar reduces the bioavailability of thiacloprid in soil, but the delayed degradation and increased earthworm accumulation in aged biochar-amended soil imply that the environmental risks of biochar application to earthworms remain. [ABSTRACT FROM AUTHOR]