ABSTRACT
A robust and sensitive method utilising a hybrid ion chromatography tandem mass spectrometry system (IC-MS/MS) for the simultaneous determination of nine (9) highly polar anionic pesticides (chlorate, ethephon, fosetyl aluminium, glufosinate, glyphosate, N-acetyl AMPA, N-acetyl glyphosate, perchlorate and phosphonic acid) in fruit and vegetables is described. Mean recoveries (nâ¯=â¯6) at two fortification levels ranged from 83 to 112% with %CVs in the range 3-14%. The linearity range was 0.005-0.4â¯mgâ¯kg-1 and R2 values were >0.99 and the sensitivity of the method allowed (20× or 30×) dilution of samples. Provision of qualitative determination of aminomethylphosphonic acid (AMPA) was also facilitated via minor modification of the chromatographic conditions. Compliance with method validation criteria, survey results from the statutory UK/EU Pesticide Residues in Food 2018 programmes i.e. pea, pineapple, melon and successful z-scores for a UK proficiency testing scheme sample (ethephon in pineapple) demonstrate successful application of this IC-MS/MS method.
Subject(s)
Food Contamination/analysis , Fruit/chemistry , Pesticide Residues/analysis , Tandem Mass Spectrometry/methods , Vegetables/chemistry , Anions/analysis , Anions/chemistry , Chromatography, Liquid/methods , European Union , Food Analysis/methods , Limit of Detection , Organophosphorus Compounds , Pesticide Residues/chemistry , Reproducibility of Results , Tandem Mass Spectrometry/instrumentationABSTRACT
CCAAT/enhancer binding protein ß (C/EBPß) is required for murine mammary ductal morphogenesis and alveologenesis. Progesterone is critical for proliferation and alveologenesis in adult mammary glands, and there is a similar requirement for progesterone receptor isoform B (PRB) in alveologenesis. We examined C/EBPß regulation of PR expression. All three C/EBPß isoforms, including typically inhibitory LIP, transactivated the PR promoter. LIP, particularly, strongly synergized with c-Jun to drive PR transcription. Endogenous C/EBPß and c-Jun stimulated a PR promoter-reporter and these two factors showed promoter occupancy on the endogenous PR gene. Additionally, LIP overexpression elevated endogenous PR protein expression. In pregnancy, both PRB and the relative abundance of LIP among C/EBPß isoforms increase. Consistent with a role in PRB expression, in vivo C/EBPß and PR isoform A expression showed mutually exclusive localization in mammary epithelium, while C/EBPß and PRB largely co-localized. We suggest a critical role for C/EBPß, particularly LIP, in PRB expression.
