The 66 kDa isoform of the mammalian She gene promotes adipogenesis, and p66Shc−/− mice accumulate less body weight than wild‐type (WT) mice. As the metabolic consequences of the leaner phenotype of ...p66Shc−/− mice is debated, we hypothesized that gut microbiota may be involved. We confirmed that p66Shc−/− mice gained less weight than WT mice when on a high‐fat diet (HFD), but they were not protected from insulin resistance and glucose intolerance. p66Shc deletion significantly modified the composition of gut microbiota and their modification after an HFD. This was associated with changes in gene expression of Il‐1b and regenerating islet‐derived protein 3 g (Reg3g) in the gut and in systemic trimethylamine N‐oxide and branched chain amino acid levels, despite there being no difference in intestinal structure and permeability. Depleting gut microbiota at the end of HFD rendered both strains more glucose tolerant but improved insulin sensitivity only in p66Shc−/− mice. Microbiota‐depleted WT mice cohoused with microbiota‐competent p66Shc−/− mice became significantly more insulin resistant than WT mice cohoused with WT mice, despite no difference in weight gain. These findings reconcile previous inconsistent observations on the metabolic phenotype of p66Shc−/− mice and illustrate the complex microbiome‐host‐genotype interplay under metabolic stress.—Ciciliot, S., Albiero, M., Campanaro, S., Poncina, N., Tedesco, S., Scattolini, V., Dalla Costa, F., Cignarella, A., Vettore, M., Di Gangi, I. M., Bogialli, S., Avogaro, A., Fadini, G. P. Interplay between gut microbiota and p66Shc affects obesity‐associated insulin resistance. FASEB J. 32, 4004–4015 (2018). www.fasebj.org
A rapid, specific and sensitive procedure for determining residues of eight widespread used quinolone antimicrobials in bovine milk is presented. The method is based on the matrix solid-phase ...dispersion technique with hot water as extractant followed by LC/MS/MS. The entire sample treatment did not take more than 40
min. Hot water appeared to be an efficient extracting medium, since absolute recoveries of the analytes in milk were 77–90%. The method proved to be robust as matrix effects did not affect significantly the accuracy of the method, as evidenced by analyzing six different batches of milk. Using norfloxacin as surrogate analyte, the accuracy of the method at three different spike levels of the analytes in milk was 93–110% with RSDs not larger than 10%. On the basis of a S/N of 10, estimated LOQs of this method range from 0.3 to 1.5
ng/ml, well below the tolerance levels of quinolones in milk set by the European Union.
A series of novel diisocyanide ligands (o-CNC6H4O)2Y (diNC-1: Y = P(O)Ph; diNC-2: Y = o-C(O)C6H4C(O); diNC-3: Y = m-C(O)C6H4C(O); diNC-4: Y = C(O)C2H4C(O); diNC-5: Y = trans-C(O)C2H2C(O)) was ...successfully synthesized by reaction of lithium 2-isocyanophenate (generated in situ from benzoxazole and n-BuLi) and a diacylic or phosphonic dichloride. The corresponding platinum(II) complexes of general formula PtX2(diNC)1,2 (X = Cl, Me; diNC = diisocyanide ligand) were isolated by simple substitution of 1,5-cyclooctadiene in the starting PtX2(COD) complexes. The structure of the complexes, mononuclear or dinuclear, was confirmed by single-crystal X-ray analysis. A dinuclear complex of formula {(μ-diNC)cis-PtCl2(PPh3)2} could also be obtained with the diisocyanide ligand having a rigid fumaryl bridge and consequently the isocyanide moieties pointing in opposite directions. All the complexes were employed as catalysts in the hydroarylation of alkynes, showing generally good activity and selectivity toward the trans-hydroarylation product. With N-methylindole as aromatic substrate the major product was instead a heterocycle:alkyne 2:1 adduct.
The present paper reports the determination of the tri-amine N-(3-aminopropyl)-N-dodecyl-1,3-propanediamine (TA) present in a raw material called LONZABAC used to formulate various, widely used ...commercial biocides. The active principle, TA, is present in LONZABAC together with other molecules at lower concentration levels. Three independent analytical approaches, namely solution NMR spectroscopy, liquid chromatography coupled to high resolution mass spectrometry (LC/HRMS) and acid-base titration in mixed solvent, were used to overcome the problem of the non-availability of the active principle as high purity standard. NMR analysis of raw material, using a suitable internal standard, evidenced in all analyzed lots the presence of the active principle, the N-dodecyl-1,3-propanediamine (DA) and the n-dodecylamine (MA) and the absence of non-organic, NMR-inactive species. NMR peak integration led to a rough composition of the MA:DA:TA as 1:9:90. The LC/HRMS analysis allowed the accurate determination of DA and MA and confirmed in all samples the presence of the TA, which was estimated by difference: MA=1.4±0.3%, DA=11.1±0.7%, TA=87.5±1.3%. The obtained results were used to setup an easy, rapid and cheap acid-base titration method able to furnish a sufficiently accurate evaluation of the active principle both in the raw material and in diluted commercial products. For the raw material the results were: TA+MA=91.1±0.8% and DA-MA=8.9±0.8%, statistically coherent with LC/MS ones. The LC/MS approach demonstrated also its great potentialities to recognize trace of the biocide components both in environmental samples and in the formulated commercial products.
The mononuclear tricationic bis(di-N-heterocyclic carbene) gold(III) complex 13+ of formula Au(MeImCH2ImMe)23+ (Im = imidazol-2-ylidene) was successfully synthesized by transmetalation of the ...di(N-heterocyclic carbene) ligand from the corresponding silver(I) complex to KAuBr4. The counteranion of the gold(III) cationic complex depends on the synthetic procedure. The crude product, isolated by the transmetalation reaction, consists of infinite (Ag4Br7 3–) n ribbons. By adding a stoichiometric amount of AgPF6, the complete precipitation of AgBr is achieved, and the counteranions are PF6 –. If substoichiometric amounts of silver salts are added, then the (Ag4Br7 3–) n ribbon breaks, and silverbromides anionic aggregates of lower nuclearity are obtained, for example, Ag2Br6 4–. The X-ray crystal structures of 1-Ag 4 Br 7 , 1-PF 6 , and 1-Br,(Ag 2 Br 6 ) 0.5 were determined. The complexes with any type of bromide present interactions between the Au center and two bromides of the counteranions so that the geometry around gold is pseudo-octahedral. The gold-bromide interaction has been investigated via DFT calculations and is mainly electrostatic.
Nanoplastics are anticipated to be ubiquitous in various environmental compartments. However, challenges in analytical methods hinder our understanding of risks related to specific nanplastics ...characteristics such as size and chemical compositions, and interactions between nanoplastics and microorganisms. In this study, we applied fit-for-purpose analytical methods and techniques to understand how nanoplastic chemical composition influences their interaction with bacteria collected from activated sludge. When exposed to polystyrene (PS) and polyvinyl chloride (PVC) nanoplastics for 5 days, the nanoplastics attached to the bacteria. Specifically, on day 1, there was a significant predominance of PS nanoplastics over PVC ones of similar size and shape, possibly due to differences in their chemical composition. After 5 days, there is a substantial decrease in nanoplastics attached to bacteria, suggesting bacterial defence mechanisms may reduce particles attachment over time. The overall bacterial community structure demonstrated a high degree of resilience. This resilience highlights the ability of microbial communities to maintain their structure despite nanoplastic stressors, as evidenced by consistent alpha diversity, PCoA, and PERMANOVA results. Understanding these mechanisms is crucial for assessing nanoplastic fate and thus environmental impacts.
•The chemical composition of nanoplastic influences their attachment to bacteria.•The number of PS nanoplastics attached to bacteria is more than PVC nanoplastics.•Exposure to nanoplastic did not influence communities' structure of AS bacteria.
A simple and rapid method able to determine residues of erythromycin A, tylosin and tilmicosin in whole eggs is presented here. The analytical protocol involves a one-step extraction followed by ...liquid chromatography (LC)–tandem mass spectrometry. Analytes were extracted from 1
g of egg spiked with an internal standard (josamycin) with acetonitrile. In terms of accuracy, matrix effect and ion signal stability, no extract cleanup was found to be necessary. After partial solvent removal, the final extract was injected into the LC column. Extraction was effective, since absolute recovery of the analyte in egg at their maximum residue limit (MRL) level was 85–102%. Estimated limits of quantification (S/N
=
10) were 0.2–0.5
ng/g. Based on the EU Commission Decision 2002/657/EC, the method was in-house validated in terms of ruggedness, specificity, linearity, within-laboratory reproducibility, decision limit (CC
α) and detection capability (CC
β). The within-laboratory reproducibility, expressed as RSD (
n
=
18 at the MRL levels), was not higher than 13%. After validation, a short study on EA depletion in eggs was conducted after administration of this drug to laying hens.
