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

Discovery, Optimization, and Biological Evaluation of Sulfonamidoacetamides as an Inducer of Axon Regeneration

Axon regeneration after injury in the central nervous system is hampered in part because if an age-dependent decline in the intrinsic axon growth potential, and one of the strategies to stimulate axon growth in injured neurons involves pharmacological manipulation of implicated signaling pathways. Here we report phenotypic cell-based screen of chemical libraries and structure–activity-guided optimization that resulted in the identification of compound <b>7p</b> which promotes neurite outgrowth of cultured primary neurons derived from the hippocampus, cerebral cortex, and retina. In an animal model of optic nerve injury, compound <b>7p</b> was shown to induce growth of GAP-43 positive axons, indicating that the in vitro neurite outgrowth activity of compound <b>7p</b> translates into stimulation of axon regeneration in vivo. Further optimization of compound <b>7p</b> and elucidation of the mechanisms by which it elicits axon regeneration in vivo will provide a rational basis for future efforts to enhance treatment strategies

Effects of lifetime cumulative ginseng intake on cognitive function in late life

Abstract Background We investigated the effects of lifetime cumulative ginseng intake on cognitive function in a community-dwelling population-based prospective cohort of Korean elders. Methods Community-dwelling elders (N = 6422; mean age = 70.2 ± 6.9 years, education = 8.0 ± 5.3 years, female = 56.8%) from the Korean Longitudinal Study on Cognitive Aging and Dementia were included. Among them, 3918 participants (61.0%) completed the 2-year and 4-year follow-up evaluations. Subjects were categorized according to cumulative ginseng intake at baseline evaluation; no use group, low use (< 5 years) group, and high use (≥ 5 years) group. One-way analysis of covariance (ANCOVA) was conducted to compare the impact of cumulative ginseng intake on baseline Consortium to Establish a Registry for Alzheimer’s Disease Assessment Packet neuropsychological battery total score (CERAD total score) and Mini-Mental State Examination (MMSE) score among the three groups while adjusting for potential covariates. A repeated-measures ANCOVA was performed to investigate the impacts on the changes in CERAD total scores and MMSE scores during the 4 years of follow-up. Results The high use group showed higher CERAD total scores compared to the no use group after controlling for age, sex, education years, socioeconomic status, smoking, alcohol intake, presence of hypertension, stroke history, Geriatric Depression Scale, Cumulative Illness Rating Scale, and presence of the APOE e4 allele (F(2, 4762) = 3.978, p = 0.019). The changes of CERAD total score for 2 or 4 years of follow-up did not differ according to the use of ginseng. Conclusions Cumulative ginseng use for longer than 5 years may be beneficial to cognitive function in late life

Additional file 1: of Effects of lifetime cumulative ginseng intake on cognitive function in late life

Table S1. Baseline characteristics of participants and those lost to follow-up (DOCX 22 kb