Effects of Zinc Adaptation on Histological Morphology, Antioxidant Responses, and Expression of Immune-Related Genes of Grass Carp (Ctenopharyngodon idella).

The study was conducted to evaluate the effect of zinc adaptation on histological morphology and antioxidant and immune responses of grass carp(Ctenopharyngodon idella). A total of 180 young grass carp (20.0 ± 2.0 g) was equally distributed into 9 groups, and triplicate groups were subjected to 0 µg/L Zn2+ (control group), 200 µg/L Zn2+, and 300 µg/L Zn2+ solution for 42 days, respectively. The results indicated that the liver and gill have obvious pathological changes after long-term adaptation to zinc except the intestine; the zinc adaptation can positively influence intestinal morphology. The activities of GPX (glutathione peroxidase activity), SOD (superoxide dismutase), and CAT (Catalase) were significantly increased in zinc treatment groups (P < 0.05). The genes expression levels of CuZnSOD (copper zinc superoxide dismutase), CAT, Hsp70 (heat shock protein-70), IL-1b (interleukin-1-b), and TGF-ß1 (transforming growth factor-ß1) were upregulated in the gill and intestine of grass carp following waterborne adaptation to zinc solution for 42 days (P < 0.05). In conclusion, zinc adaptation has different effects on organs of grass carp and may reduce the inflammatory response of the body's gills and intestines by improving the body's antioxidant and anti-stress defense capabilities.

Effect of Spirulina and Ferrous Fumarate on Intestinal Morphology and the Diversity of Gut Microbiota of Yellow River Carp.

The study aimed to investigate the effect of diets supplemented with Spirulina and the mixture of Spirulina and ferrous fumarate on intestinal morphology and the diversity of gut microbiota of Yellow River carp. The results showed that the Spirulina and the mixture of Spirulina and ferrous fumarate could promote the development of intestinal villi, increase the thickness of intestinal muscular layer. Additionally, high-throughput sequencing of 16S rRNA gene revealed that the Spirulina and the mixture of Spirulina and ferrous fumarate could alter the composition, diversity, and richness of intestinal microbial communities. The relative abundances of the predominant phyla Firmicutes and Verrucomicrobia showed significant changes at the phylum level after fed with Spirulina and ferrous fumarate. At the genus level, the predominant genera with marked differences in abundances were Flavobacterium, Aeromonas, and Brevinema. In conclusion, this study indicated the Spirulina and the ferrous fumarate could alter the intestinal microbiota structure and could also cause positive impacts on the health of Yellow River carp. This study provides the valuable information for elucidating the mechanisms of Spirulina and ferrous fumarate in aquatic animals in the future.

A time-resolved spectroscopic study of the bichromophoric phototrigger 3',5'-dimethoxybenzoin diethyl phosphate: interaction between the two chromophores determines the reaction pathway.

3',5'-Dimethoxybenzoin (DMB) is a bichromophoric system that has widespread application as a highly efficient photoremovable protecting group (PRPG) for the release of diverse functional groups. The photodeprotection of DMB phototriggers is remarkably clean, and is accompanied by the formation of a biologically benign cyclization product, 3',5'-dimethoxybenzofuran (DMBF). The underlying mechanism of the DMB deprotection and cyclization has, however, until now remained unclear. Femtosecond transient absorption (fs-TA) spectroscopy and nanosecond time-resolved resonance Raman (ns-TR(3)) spectroscopy were employed to detect the transient species directly, and examine the dynamic transformations involved in the primary photoreactions for DMB diethyl phosphate (DMBDP) in acetonitrile (CH(3)CN). To assess the electronic character and the role played by the individual sub-chromophore, that is, the benzoyl, and the di-meta-methoxybenzylic moieties, for the DMBDP deprotection, comparative fs-TA measurements were also carried out for the reference compounds diethyl phosphate acetophenone (DPAP), and 3',5'-dimethoxybenzylic diethyl phosphate (DMBnDP) in the same solvent. Comparison of the fs-TA spectra reveals that the photoexcited DMBDP exhibits distinctly different spectral character and dynamic evolution from those of the reference compounds. This fact, combined with the related steady-state spectral and density functional theoretical results, strongly suggests the presence in DMBDP of a significant interaction between the two sub-chromophores, and that this interaction plays a governing role in determining the nature of the photoexcitation and the reaction channel of the subsequent photophysical and photochemical transformations. The ns-TR(3) results and their correlation with the fs-TA spectra and dynamics provide evidence for a novel concerted deprotection-cyclization mechanism for DMBDP in CH(3)CN. By monitoring the direct generation of the transient DMBF product, the cyclization time constant was determined unequivocally to be approximately 1 ns. This indicates that there is little relevance for the long-lived intermediates (>10 ns) in giving the DMBF product, and excludes the stepwise mechanism proposed in the literature as the major pathway for the DMB cyclization reaction. This work provides important new insights into the origin of the 3',5'-dimethoxy substitution effect for the DMB photodeprotection. It also helps to clarify the many different views presented in previous mechanistic studies of the DMB PRPGs. In addition to this, our fs-TA results on the reference compound DMBnDP in CH(3)CN provide the first direct observation (to the best of our knowledge) showing the predominance of a prompt (approximately 2 ps) heterolytic bond cleavage after photoexcitation of meta-methoxybenzylic compounds. This provides insight into the long-term controversies about the photoinitiated dissociation mode of related substituted benzylic compounds.

Photophysics and photodeprotection reactions of p-methoxyphenacyl phototriggers: an ultrafast and nanosecond time-resolved spectroscopic and density functional theory study.

Time-resolved spectroscopic experiments were performed to investigate the kinetics and mechanisms of the photodeprotection reactions for p-methoxyphenacyl (pMP) compounds, p-methoxyphenacyl diethyl phosphate (MPEP) and diphenyl phosphate (MPPP). The experimental results reveal that compared to the previous reports for the counterpart p-hydroxyphenacyl (pHP) phosphates, the (3)npi*/pipi* mixed character triplet of pMP acts as a reactive precursor that leads to the subsequent solvent and leaving group dependent chemical reactions and further affects the formation of photoproducts. The MPPP triplet in H(2)O/CH(3)CN and in fluorinated alcohols shows a rapid heterolytic cleavage (tau approximately 5.4 ns) that results in deprotection and formation of a solvolytic rearrangement product, whereas the MPPP triplet in CH(3)CN and the MPEP triplet in CH(3)CN and H(2)O/CH(3)CN and fluorinated alcohols decay on a much longer time scale (tau approximately 100 ns) with little observation of the rearrangement product. The density functional theory (DFT) calculations reveal a substantial solvation effect that is connected with the methoxy versus hydroxyl substitution in accounting for the different deprotection reactivity of pMP and pHP compounds. The results reported here provide new insight in elucidating the solvent and leaving group dependent dual reactivity of pMP compounds on the formation of the rearrangement versus reductive photoproduct.

Resonance Raman characterization of the different forms of ground-state 8-substituted 7-hydroxyquinoline caged acetate compounds in aqueous solutions.

To investigate the substituent effect on the distribution of the forms of the ground-state species of 8-substituted 7-hydroxyquinolines, ultraviolet-absorption and resonance Raman experiments were performed for 8-chloro-7-hydroxyquinoline (CHQ-OAc) and 8-cyano-7-hydroxyquinoline (CyHQ-OAc) in acetonitrile (MeCN), in NaOH-H(2)O/MeCN (60:40, v/v, pH 11-12), and in H(2)O/MeCN (60:40, v/v, pH 6-7) solutions, and these results were compared to those previously reported for the 8-bromo-7-hydroxyquinoline (BHQ-OAc) compound. Swapping a bromine atom in BHQ-OAc for a chlorine atom in CHQ-OAc causes the amount of the tautomeric species to become larger, although the neutral species is still the predominant species for both systems in water-rich solutions. The absorption spectra and the resonance Raman spectra of CyHQ-OAc suggest that, because of the strong electron-withdrawing nature of the cyano substituent, a measurable amount of the anionic species is present and the tautomeric species cannot be easily detected in water-rich solutions. The results reported here reveal large substituent effects on the distribution of the different forms of the XHQ-OAc compounds in largely aqueous solutions. The steric effect of the 8-substituted group and competitive hydrogen bonding between the 8-substituted group and water molecules hinders the formation of a cyclic BHQ-OAc-water complex, and the electron-withdrawing property of the 8-substituted group enhances the deprotonation of the phenol group while disfavoring the formation of the positively charged quinoline nitrogen. We briefly discuss the implications of the substituent effects for using these compounds as phototriggers.

Time-resolved resonance Raman and density functional theory investigation of the photochemistry of (S)-ketoprofen.

Ketoprofen is known to induce photosensitivity due to its specific structure and electronic features, and this limits its use in medical applications. In this Article, the photochemistry of (S)-ketoprofen has been investigated by time-resolved resonance Raman spectroscopy to gain additional information so as to better elucidate the possible photochemical reaction mechanism of ketoprofen in different solvents. In nonaqueous solvents like neat acetonitrile and isopropyl alcohol, and 1:1 acetonitrile:water and 1:1 acetonitrile:acidic water aqueous solvents, (S)-ketoprofen exhibits benzophenone-like photochemistry to produce a triplet state, which in turn produces a ketyl radical-like species that then undergoes a cross-coupling reaction with either a dimethyl radical (which is generated by hydrogen abstraction of isopropyl alcohol) or a water molecule, respectively, at the para-position to form a transient species that has a lifetime up to the microsecond time scale. However, photolysis of (S)-ketoprofen in a 1:1 acetonitrile:alkaline water solution and 3:7 acetonitrile:phosphate buffered solution appears to undergo a prompt decarboxylation reaction. Only one species was observed in the nanosecond time-resolved resonance Raman experiments under these conditions, and this species was tentatively assigned to be a triplet protonated biradical carbanion.

Resonance Raman characterization of different forms of ground-state 8-bromo-7-hydroxyquinoline caged acetate in aqueous solutions.

The 8-bromo-7-hydroxyquinolinyl group (BHQ) is a derivative of 7-hydroxyquinoline (7-HQ) and BHQ molecules coexisting as different forms in aqueous solution. Absorption and resonance Raman spectroscopic methods were used to examine 8-bromo-7-hydroxyquinoline protected acetate (BHQ-OAc) in acetonitrile (MeCN), H(2)O/MeCN (60:40, v/v, pH 6 approximately 7), and NaOH-H(2)O/MeCN (60:40, v/v, pH 11 approximately 12) to obtain a better characterization of the forms of the ground-state species of BHQ-OAc in aqueous solutions and to examine their properties. The absorption spectra of BHQ-OAc in water show no absorption bands of the tautomeric species unlike the strong band at about 400 nm observed for the tautomeric form in 7-HQ aqueous solution. The resonance Raman spectra in conjunction with Raman spectra predicted from density functional theory (DFT) calculations reveal the observation of a double Raman band system characteristic of the neutral form (the nominal C=C ring stretching, C-N stretching, and O-H bending modes at 1564 and 1607 cm(-1)) and a single Raman band diagnostic of the enol-deprotonated anionic form (the nominal C=C ring, C-N, and C-O(-) stretching modes in the 1593 cm(-1) region). These results suggest that the neutral form of BHQ-OAc is the major species in neutral aqueous solution. There is a modest increase in the amount of the anionic form and a big decrease in the amount of the tautomeric form of the molecules for BHQ-OAc compared to 7-HQ in neutral aqueous solution. The presence of the 8-bromo group and/or competitive hydrogen bonding that hinder the formation and transfer process of a BHQ-OAc-water cyclic complex may be responsible for this large substituent effect.

[Degradation of N-nitrosodimethylamine by Palladium/ Iron Bimetallic Composite Catalytic Fiber].

N-nitrosodimethylamine (NDMA) in the water environment is a carcinogenic organic contaminant, which can be converted to hypotoxic compounds by zero-valent iron degradation. For the removal of trace NDMA in water, the theory and efficiency of zero-valent iron degradation should be intensely researched. In this study, the polypropylene (PP) fibers were chosen as substrate materials and the composite catalyst fibers containing Pd/Fe0 bimetal were prepared by the UV irradiation-coordination method for the removal of trace NDMA. Pd/Fe0/PP-g-AA was characterized by scanning electron microscope, inductively coupled plasma atomic emission spectrometry, and X-ray photoelectron spectroscopy. The NDMA removal by Pd/Fe0/PP-g-AA under different conditions was investigated. The results indicated that when the acrylic acid monomer mass fraction was 20%, the composite catalytic fiber Pd/Fe0/PP-g-AA showed a better degradation effect on NDMA. The removal of NDMA followed the pseudo-first-order reaction kinetics model. The initial NDMA concentration and the pH of the solution could not greatly influence the catalytic degradation of trace amounts of NDMA. The presence of 3CO2- and NO3- significantly inhibited the degradation of NDMA. However, the NDMA degradation had been less affected by SO42-, HCO3-, and nature organic matter (NOM) existing in the solution.

Aromatic annulation strategy for naphthalenes fused at 1,2- and 3,4-positions with two heterocycles.

An efficient regioselective naphthoannulation strategy able to fuse a newly formed naphthalene ring at its 1,2- and 3,4- positions to two different heterocycles has been developed.