Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Ureido Derivatives of Neoabietic Acid

A series of ureido derivatives of neoabietic acid were synthesized by application of Curtius rearrangement reaction to neoabietic acid and amines. Structure characterization of these compounds was done by 1H-NMR, 13C-NMR and HRMS spectral analysis

Excessive Lipid Peroxidation in Uterine Epithelium Causes Implantation Failure and Pregnancy Loss

Abstract The uterine epithelium undergoes a dramatic spatiotemporal transformation to enter a receptive state, involving a complex interaction between ovarian hormones and signals from stromal and epithelial cells. Redox homeostasis is critical for cellular physiological steady state; emerging evidence reveals that excessive lipid peroxides derail redox homeostasis, causing various diseases. However, the role of redox homeostasis in early pregnancy remains largely unknown. It is found that uterine deletion of Glutathione peroxidase 4 (GPX4), a key factor in repairing oxidative damage to lipids, confers defective implantation, leading to infertility. To further pinpoint Gpx4’s role in different cell types, uterine epithelial‐specific Gpx4 is deleted by a lactotransferrin (Ltf)‐Cre driver; the resultant females are infertile, suggesting increased lipid peroxidation levels in uterine epithelium compromises receptivity and implantation. Lipid peroxidation inhibitor administration failed to rescue implantation due to carbonylation of major receptive‐related proteins underlying high lipid reactive oxygen species. Intriguingly, superimposition of Acyl‐CoA synthetase long‐chain family member 4 (ACSL4), an enzyme that promotes biosynthesis of phospholipid hydroperoxides, along with uterine epithelial GPX4 deletion, preserves reproductive capacity. This study reveals the pernicious impact of unbalanced redox signaling on embryo implantation and suggests the obliteration of lipid peroxides as a possible therapeutic approach to prevent implantation defects

Additional file 1 of TOP2A deficit-induced abnormal decidualization leads to recurrent implantation failure via the NF-κB signaling pathway

Additional file 1: Figure S1. Bioinformatics analysis of differentially expressed genes in endometrium with recurrent implantation failure from GSE111974. A Volcano plot of all expressed genes in endometrial tissues of the patients with RIF and healthy controls from GSE111974. B The PPI network of the DEGs and the hub gene screening map from GSE111974

Additional file 2 of TOP2A deficit-induced abnormal decidualization leads to recurrent implantation failure via the NF-κB signaling pathway

Additional file 2: Figure S2. TOP2A inhibition enhances decidualization in T-HESCs. A Western blotting of TOP2A in DMSO-treated group and Etoposide-treated group (1μM) of T-HESCs. B IGFBP1 protein expression in T-HESCs following treatment with DMSO or Etoposide. The cultures either remained untreated or were decidualized for 4 days. C IGFBP1 and PRL mRNA expression in DMSO and Etoposide group. The cultures either remained untreated or were decidualized for 4 days. D CytoPainter phalloidin-iFluor 488 reagent was used to label filamentous actin, and immunofluorescence was used to analyze the morphological transformation of T-HESCs. Decidualized cells were treated with both 8-bromo-cAMP and MPA for 4days. (F-actin, green fluorescence signals; DAPI, blue signals; scale bar = 200μm). One-way ANOVA or Mann-Whitney U test. Data are the mean ± SEM of 3 biological replicates unless stated otherwise. *p < 0.05, **p < 0.01,***p < 0.001. ns, nonsignificant