Transcriptome Profiling of Etridiazole-Exposed Zebrafish (Danio rerio) Embryos Reveals Pathways Associated with Cardiac and Ocular Toxicities.

Etridiazole (EDZ) is a thiadiazole-containing fungicide commonly used to control Pythium and Phytophthora spp. Although previous studies have shown that EDZ is teratogenic, the exact molecular mechanisms underlying its toxicity remain unknown. In this study, a zebrafish (Danio rerio; ZF) model was used to explore the molecular pathways associated with EDZ toxicity. The whole transcriptome of ZF embryos exposed to 96 h of EDZ was analyzed, along with developmental abnormalities. EDZ-induced malformations were primarily related to the eyes, heart, and growth of the ZF. Compared to untreated ZF, etridiazole-treated ZF had 2882 differentially expressed genes (DEGs), consisting of 1651 downregulated genes and 1231 upregulated genes. Gene ontology enrichment analysis showed that DEGs were involved in biological processes, such as sensory perception, visual perception, sensory organ development, and visual system development, and showed transmembrane transporter and peptidase regulator activities. Metabolism, phototransduction, aminoacyl-tRNA biosynthesis, MAPK signaling pathway, calcium signaling pathway, and vascular smooth muscle contraction were among the most enriched KEGG pathways. The qPCR analyses of the eight random genes were in good agreement with the transcriptome data. These results suggest several putative mechanisms underlying EDZ-induced developmental deformities in ZF.

Distinct Effects of Seed Coat and Flower Colors on Metabolite Contents and Antioxidant Activities in Safflower Seeds.

Safflower is an important oilseed crop cultivated primarily for its seeds, which have pharmaceutical properties. Color is an important agronomical trait that appears to be a prior parameter for evaluating the internal quality of plant seeds. This study employs 197 safflower accessions seeds to analyze how their seed coat and flower colors affect their total oil content, fatty acid composition, total phenolic content (TPC), N-(p-coumaroyl)serotonin (CS) and N-feruloylserotonin (FS) contents, and [2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS)] radical scavenging activities. Significant variations were observed in the targeted metabolite contents and antioxidant properties among genotypes. Notably, the linoleic acid content, total unsaturated fatty acid content, the ratio of total unsaturated fatty acid to total saturated fatty acid, CS, FS, ABTS, and DPPH scavenging capacities varied significantly based on seed coat color, with white-seeded genotypes having the highest average values of these parameters. Moreover, the linoleic acid content differed significantly (p < 0.05) among the genotypes with varying flower colors, with white-flowered accessions having the highest average content. Furthermore, genotypes K185105 (No. 75) and K175278 (No. 146) were identified as promising genetic resources with health benefits. Overall, these findings reveal that seed coat and flower colors distinctly affect metabolite contents and antioxidant properties in safflower seeds.

Effect of capsaicinoids in hot pepper powder on microbial community and free sugar during kimchi fermentation.

Effect of capsaicinoids in hot pepper powder (HP) contains various chemical compounds, including capsaicin and dihydrocapsaicin, which are the main ingredients of the spicy taste. To evaluate the effect of HP on the microbial community in kimchi fermentation, kimchi [kimchi-HP, kimchi-HPE and kimchi-HPER made by adding HP, HP alcohol extract (HPE) and HPE residues (HPER)] was fermented at 4°C for 28 days. The pH and titratable acidity of the samples and the number of bacteria changed with fermentation time. Kimchi-HPER had significantly higher total viable and lactic acid bacteria (LAB) than other samples after 28 days of fermentation. The capsaicinoids content did not differ before and after fermentation, whereas the major free sugar content decreased, and the mannitol content increased. The principal component analysis (PCA) biplots showed similar patterns between kimchi-HP and -HPE. It was confirmed that Leuconostoc and Weissella were related to the initial fermentation, and Lactobacillus was involved in late fermentation. Kimchi-HP and kimchi-HPE increased the ratio of Lactobacillus sakei and decreased that of Leuconostoc mesenteroides compared to kimchi-HPER. Overall, these results revealed that capsaicinoids contained in HP affected Lactobacillus proliferation and mannitol increase during kimchi fermentation.

Aminolysis of O-aryl thionobenzoates: amine basicity combines with modulation of the nature of substituents in the leaving group and thionobenzoate moiety to control the reaction mechanism.

A kinetic study is reported for aminolysis of O-Y-substituted phenyl thionobenzoates (1a-f) and O-4-nitrophenyl X-substituted thionobenzoates (2a-f) in 80 mol % H2O/20 mol % DMSO at 25.0 +/- 0.1 degrees C. The reaction proceeds through one or two intermediates (i.e., a zwitterionic tetrahedral intermediate T(+/-) and its deprotonated form T(-)) depending on the basicity difference between the nucleophile and nucleofuge, that is, the reaction proceeds through T(+/-) when the leaving aryloxide is less basic than the attacking amine, but through T(+/-) and T(-) when the leaving group is more basic than the amine. However, the reaction mechanism is not influenced by the electronic nature of the substituent X in the nonleaving group. The Hammett plot for the reactions of 2a-f with benzylamine is consisted of two intersecting straight lines, which might be interpreted as a change in the rate-determining step (RDS). However, the Yukawa-Tsuno plot for the same reactions exhibits an excellent linear correlation, indicating that the nonlinear Hammett plot is not due to a change in the RDS but caused by stabilization of the ground-state of the substrate through resonance interaction between the electron-donating substituent X and the thionocarbonyl moiety.

Analysis of linear free-energy relationships combined with activation parameters assigns a concerted mechanism to alkaline hydrolysis of x-substituted phenyl diphenylphosphinates.

A kinetic study is reported for alkaline hydrolysis of X-substituted phenyl diphenylphosphinates (1 a-i). The Brønsted-type plot for the reactions of 1 a-i is linear over 4.5 pK(a) units with beta(lg)=-0.49, a typical beta(lg) value for reactions which proceed through a concerted mechanism. The Hammett plots correlated with sigma(o) and sigma(-) constants are linear but exhibit many scattered points, while the corresponding Yukawa-Tsuno plot results in excellent linear correlation with rho=1.42 and r=0.35. The r value of 0.35 implies that leaving-group departure is partially advanced at the rate-determining step (RDS). A stepwise mechanism, in which departure of the leaving group from an addition intermediate occurs in the RDS, is excluded since the incoming HO(-) ion is much more basic and a poorer nucleofuge than the leaving aryloxide. A dissociative (D(N) + A(N)) mechanism is also ruled out on the basis of the small beta(lg) value. As the substituent X in the leaving group changes from H to 4-NO(2) and 3,4-(NO(2))(2), DeltaH++ decreases from 11.3 kcal mol(-1) to 9.7 and 8.7 kcal mol(-1), respectively, while DeltaS++ varies from -22.6 cal mol(-1) K(-1) to -21.4 and -20.2 cal mol(-1) K(-1), respectively. Analysis of LFERs combined with the activation parameters assigns a concerted mechanism to the current alkaline hydrolysis of 1 a-i.

Modification of both the electrophilic center and substituents on the nonleaving group in pyridinolysis of O-4-nitrophenyl benzoate and thionobenzoates.

A kinetic study is reported for reactions of 4-nitrophenyl benzoate (1c) and O-4-nitrophenyl X-substituted thionobenzoates (2a-e) with a series of pyridines in 80 mol % H2O/20 mol % dimethyl sulfoxide (DMSO) at 25.0 +/- 0.1 degrees C. O-4-Nitrophenyl thionobenzoate (2c) is more reactive than its oxygen analogue 1c toward all the pyridines studied. The Brønsted-type plot is linear with beta(nuc)=1.06 for reactions of 1c but curved for the corresponding reactions of 2c with beta(nu)c decreasing from 1.38 to 0.38 as the pyridine basicity increases, indicating that the reaction mechanism is also influenced on changing the electrophilic center from C=O to C=S. The curvature center of the curved Brønsted-type plots (defined as pK(a)(o)) occurs at pKa = 9.3 regardless of the electronic nature of the substituent X in the nonleaving group. The Hammett plot for reactions of 2a-e with 4-aminopyridine is nonlinear, i.e., the substrates having an electron-donating substituent exhibit negative deviations from the Hammett plot. However, the Yukawa-Tsuno plot for the same reactions exhibits good linear correlation, indicating that the negative deviations shown by these substrates arise from stabilization of the ground state through resonance interaction between the electron-donating substituent X and the C=S bond.

Solvent effect on the alpha-effect: ground-state versus transition-state effects; a combined calorimetric and kinetic investigation.

In a study of the solvent effect on the alpha-effect, second-order rate constants (kNu-) have been determined spectrophotometrically for reactions of a series of substituted phenyl acetates with butan-2,3-dione monoximate (Ox-, alpha-nucleophile) and p-chlorophenoxide (p-ClPhO-, reference nucleophile) in DMSO-H2O (DMSO = dimethyl sulfoxide) mixtures of varying compositions at 25.0 +/- 0.1 degrees C. The magnitude of the alpha-effect, kOx-/kp-ClPhO-, increases as the DMSO content in the medium increases up to 40-50 mol %, reaching 500, one of the largest alpha-effect values, and then decreases on further addition of DMSO, resulting in a bell-shaped alpha-effect profile regardless of the nature of the substrates. The magnitude of the alpha-effect is found to be significantly dependent on the substrates (or, more quantitatively, on beta(nuc)). Thus, beta(nuc) is an important predictor of the magnitude of the alpha-effect. The bell-shaped alpha-effect profile found in the present system is attributed to the differential change in the sensitivity of the medium effect on the Ox- and p-ClPhO- systems but not due to a change in the reaction mechanism or to a drastic change in the basicity of the two nucleophiles on addition of DMSO to the medium. Through application of calorimetric measurements of ground-state solvation combined with the diagnostic beta(nuc) values, it is shown that the transition-state effect is more dominant than the ground-state effect as the origin of the alpha-effect in the present system.