Different rearing conditions alter gut microbiota composition and host physiology in Shaoxing ducks.

Emerging evidences have linked the gut microbiota to poultry physiology. Gut microbiota composition in Shaoxing ducks were profiled under different rearing conditions: raised on the litter floor and the plastic mesh floor. A total of 46 and 39 luminal content samples from the duodenum, ileum, and cecum of the ducks reared under the two conditions were analyzed by 16S rRNA gene amplicon sequencing analysis. Proteobacteria (48.66%), Proteobacteria (33.38%), and Bacteroidetes (55.35%) were the dominant phyla in the duodenum, ileum, and cecum of the ducks reared on the litter floor respectively, while Firmicutes (30.80%), Firmicutes (66.62%) and Bacteroidetes (47.15%) were the topmost phyla in the duodenum, ileum, and cecum of the ducks reared on the plastic mesh floor. Physiologically, the height of villi and the ratio of villus height to crypt depth in the ileum and duodenum were significantly greater in the ducks reared on plastic mesh floor. Furthermore, our results demonstrate that the gut microbiota was significantly associated with the duck phenotypes, such as chest depth and serum estradiol levels (p < 0.05), which were altered by the different rearing conditions. Collectively, our results showed that the rearing floor types have an important effect on the gastrointestinal microbial composition of ducks.

Resonance light scattering detection of fructose bisphosphates using uranyl-salophen complex-modified gold nanoparticles as optical probe.

In this paper, we report a resonance light scattering (RLS) method for the determination of fructose bisphosphates (FBPs) in water solution using fructose 1,6-bisphosphate (F-1,6-BP) as a model analyte without the procedure of extracting target analyte. The method used a type of modified gold nanoparticles (GNPs) as optical probe. The modified GNPs are uranyl-salophen-cysteamine-GNPs (U-Sal-Cy-GNPs) which are obtained through the acylation reaction of carboxylated salophen with cysteamine-capped GNPs (Cy-GNPs) to form Sal-Cy-GNPs and then the chelation reaction of uranyl with tetradentate ligand salophen in the Sal-Cy-GNPs. A FBP molecule is used easily to connect two U-Sal-Cy-GNPs to cause the aggregation of the GNPs by utilizing the specific affinity of uranyl-salophen complex to phosphate group, resulting in the production of strong RLS signal from the system. The amount of FBPs can be determined through detecting the RLS intensity change of the system. A linear range was found to be 2.5 to 75 nmol/L with a detection limit of 0.91 nmol/L under optimal conditions. The method has been successfully used to determine FBPs in real samples with the recoveries of 96.5-103.5 %.

Determination of copper (II) in foodstuffs based on its quenching effect on the fluorescence of N,N'-bis(pyridoxal phosphate)-o-phenylenediamine.

A Schiff base-type fluorescence probe was prepared for the detection of copper (II) in foodstuffs. The probe is N,N'-bis(pyridoxal phosphate)-o-phenylenediamine (BPPP). It was synthesized by utilizing the Schiff base condensation reaction of pyridoxal 5-phosphate with 1,2-phenylenediamine. BPPP has the properties of high fluorescence stability, good water solubility and low toxicity. Its maximum excitation wavelength and maximum fluorescence emission wavelength are at 389 and 448 nm, respectively. When BPPP coexists with copper (II), its fluorescence is dramatically quenched. Under a certain condition, the fluorescence intensity decreased proportionally to the concentration of copper (II) by the quenching effect. Based on this fact, we established a fluorescence quenching method for the determination of copper (II). Under optimal conditions a linear range was found to be 0.5-50 ng/mL with a detection limit of 0.2 ng/mL. The method has been applied to determine copper (II) in foodstuff samples and the analytical results show good agreement with that obtained from atomic absorption spectrometry method.

Extraction of cupric ions with ionic liquids containing polypyridine-type small molecules or peripherally pyridine-modified dendrimers.

The hydrophobic ionic liquid N-butyl-N-methylpyrrolidinium bis((trifluoromethyl)sulfonyl)amide (BMP-TFSA IL), which contains a series of flexible ionophores of polypyridine-type small molecules or two rigid ionophores of peripherally pyridine-modified PAMAM dendrimers, was used to extract cupric ions from aqueous solutions. The polypyridine-type ionophores show good selectivity toward cupric ions at pH 2. The selectivity is affected by the spacing between the two amino groups. However, the pyridine-modified dendrimers showed poor selectivity, although their extraction efficiency still depended on the pH of the aqueous solution. The ionic liquids that contained small molecular ionophores and their dendrimer analogs were reused after acid washing or electrochemical reduction. During acid washing, the nitrogen atoms of the ionophores were protonated to release the cupric ions into the aqueous phase, and the copper atoms were deposited onto the electrode surface during the electrochemical reduction accompanied by the regeneration of the ionophores.

An eight-coordinate vanadium thiolate complex with charge delocalization between V(V)-thiolate and V(IV)-thiyl radical forms.

A six-coordinate oxovanadium(V) thiolate complex and an eight-coordinate non-oxovanadium thiolate complex, [PPh(4)][VO(PS3'')(OCH(3))] (1) and [NEt(4)][V(PS3'')(2)] (2) (PS3'' = P(C(6)H(3)-3-Me(3)Si-2-S)(3)(3-)), respectively, have been isolated and structurally characterized. The former belongs to a limited collection of oxovanadium(V) thiolate complexes. The latter has an unusual coordination number of eight. More importantly, its consensus electronic structure derived from its spectroscopic data should be considered as the resonance forms of V(V)-thiolate and V(IV)-thiyl radical species. This implies that V(IV)-thiyl radical can maintain a stable presence in biological systems.

Anti-inflammatory phloroglucinols and terpenoids from Garcinia subelliptica.

Three new phloroglucinols, garcinielliptones K (1), L (2), and M (3), and two new terpenoids, garcinielliptones N (4) and O (5), have been isolated from the seeds of Garcinia subelliptica. The structures of 1-5 including their relative configurations were elucidated by spectroscopic methods and supported by computer-generated molecular modeling. Compounds 2 and 3 showed potent inhibitory effects on the release of beta-glucuronidase, and on beta-glucuronidase and histamine, respectively, from peritoneal mast cells stimulated with p-methoxy-N-methylphenethylamine (compound 48/80) in a concentration-dependent manner. Compounds 2 and 3 showed potent effects on NO production in culture media of RAW 264.7 cells in response to lipopolysaccharide (LPS). Compound 2 also showed a potent effect on NO production in culture media of N9 cells in response to LPS/interferon-gamma (IFN-gamma).

Two new protopines argemexicaines A and B and the anti-HIV alkaloid 6-acetonyldihydrochelerythrine from formosan Argemone mexicana.

Two new protopine-type alkaloids, argemexicaine A (1) and argemexicaine B (2), along with thirteen known alkaloids, were isolated from MeOH extracts of Formosan Argemone mexicana L. (Papaveraceae). Physical and spectral analyses, particularly IR and thermo-modulated 1D and 2D NMR, were used to determine the transannular conformations of the isolated protopine-type alkaloids. The known benzo[ c]phenanthridine (+/-)-6-acetonyldihydrochelerythrine (5) exhibited significant anti-HIV activity in H9 lymphocytes with EC50 and TI (Therapeutic Index) values of 1.77 microg/mL and 14.6, respectively.

NMR and ab initio studies of amination of ketenimine: direct evidence for a mechanism involving a vinylidenediamine as an intermediate.

High-level ab initio calculations were carried out in both gas phase and solvent (epsilon = 35.9) to estabilish that the amination of ketenimine proceeds via amine addition across the C=N bond rather than the C=C bond, followed by tautomerization to form amidine product. The HOMO of ketenimine is perpendicular to its molecular plane with the largest coefficient on C(beta), while the LUMO is in its molecular plane with the largest coefficient on C(alpha). Amination of ketenimine involves in-plane attack of amine nucleophile on C(alpha) (LUMO) of ketenimine. The labile vinylidenediamine intermediate trans-11 for the reaction of ketenimine 10 with n-butylamine was directly observed by means of low-temperature proton NMR spectra. The evidence confirms that the amination reaction is stepwise and proceeds via n-butylamine addition across the C=N bond of ketenimine 10 rather than the C=C bond, followed by a slower tautomerization of vinylidenediamine trans-11 to amidine 12. Even though the second step is much slower, the first step involving amine addition across the C=N bond is kinetic control. Surprisingly, in the reaction of 10 with n-BuNH(2), attack of n-BuNH(2) syn to the phenyl group on C(beta) of 10 is preferred, even though this produces a less stable product (trans-11); attack of n-BuNH(2) anti to phenyl group on C(beta) of 10 is lacking and results in serious nonbonding interactions between the two phenyls of the ketenimine, as they are pushed together in this transition state.