Vitamin C Prevents Hypogonadal Bone Loss

Epidemiologic studies correlate low vitamin C intake with bone loss. The genetic deletion of enzymes involved in de novo vitamin C synthesis in mice, likewise, causes severe osteoporosis. However, very few studies have evaluated a protective role of this dietary supplement on the skeleton. Here, we show that the ingestion of vitamin C prevents the low-turnover bone loss following ovariectomy in mice. We show that this prevention in areal bone mineral density and micro-CT parameters results from the stimulation of bone formation, demonstrable in vivo by histomorphometry, bone marker measurements, and quantitative PCR. Notably, the reductions in the bone formation rate, plasma osteocalcin levels, and ex vivo osteoblast gene expression 8 weeks post-ovariectomy are all returned to levels of sham-operated controls. The study establishes vitamin C as a skeletal anabolic agent. © 2012 Zhu et al

Limits to the cellular control of sequestered cryptophyte prey in the marine ciliate Mesodinium rubrum

The marine ciliate Mesodinium rubrum is famous for its ability to acquire and exploit chloroplasts and other cell organelles from some cryptophyte algal species. We sequenced genomes and transcriptomes of free-swimming Teleaulax amphioxeia, as well as well-fed and starved M. rubrum in order to understand cellular processes upon sequestration under different prey and light conditions. From its prey, the ciliate acquires the ability to photosynthesize as well as the potential to metabolize several essential compounds including lysine, glycan, and vitamins that elucidate its specific prey dependency. M. rubrum does not express photosynthesis-related genes itself, but elicits considerable transcriptional control of the acquired cryptophyte organelles. This control is limited as light-dependent transcriptional changes found in free-swimming T. amphioxeia got lost after sequestration. We found strong transcriptional rewiring of the cryptophyte nucleus upon sequestration, where 35% of the T. amphioxeia genes were significantly differentially expressed within well-fed M. rubrum. Qualitatively, 68% of all genes expressed within well-fed M. rubrum originated from T. amphioxeia. Quantitatively, these genes contributed up to 48% to the global transcriptome in well-fed M. rubrum and down to 11% in starved M. rubrum. This tertiary endosymbiosis system functions for several weeks, when deprived of prey. After this point in time, the ciliate dies if not supplied with fresh prey cells. M. rubrum represents one evolutionary way of acquiring photosystems from its algal prey, and might represent a step on the evolutionary way towards a permanent tertiary endosymbiosis

Vitamin C Prevents Hypogonadal Bone Loss

Abstract Epidemiologic studies correlate low vitamin C intake with bone loss. The genetic deletion of enzymes involved in de novo vitamin C synthesis in mice, likewise, causes severe osteoporosis. However, very few studies have evaluated a protective role of this dietary supplement on the skeleton. Here, we show that the ingestion of vitamin C prevents the low-turnover bone loss following ovariectomy in mice. We show that this prevention in areal bone mineral density and micro-CT parameters results from the stimulation of bone formation, demonstrable in vivo by histomorphometry, bone marker measurements, and quantitative PCR. Notably, the reductions in the bone formation rate, plasma osteocalcin levels, and ex vivo osteoblast gene expression 8 weeks post-ovariectomy are all returned to levels of sham-operated controls. The study establishes vitamin C as a skeletal anabolic agent

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

Research on Evolutionary Game of Engineering Community Members from the Perspective of Engineering Ethics

Engineering ethics is a system of ethical principles applied to engineering, which plays the role of value guidance and criterion evaluation in engineering construction activities. Based on engineering ethics, writers review the Sanmenxia Reservoir Project, and use system dynamics to systematically study the evolutionary game of engineering community members, including government, enterprise, and people, involved in the engineering activities. The results show that the engineering community is a heterogeneous community with complex game behaviors, and the correct ethical choice is the key factor that promotes the evolution of the community members to cooperative dynamic equilibrium. Good management of ethical commitment, emphasis on professionalism and public services, strengthening risk alert and avoidance are effective ways for members of the engineering community to form a cooperative game, avoid tragedy of public resources, and ultimately ensure the orderly development of projects

The effects of prenatal azithromycin exposure on offspring ovarian development at different stages, doses, and courses

Azithromycin, a commonly used macrolide antibiotic for treating chlamydial infections during pregnancy, has sparked investigations into its potential effects on offspring development. Despite these inquiries, there remains uncertainty about the specific impact of prenatal azithromycin exposure (PAzE) on offspring ovarian development and the precise ''effect window''. Pregnant mice, following clinical guidelines for azithromycin dosing, were orally administered azithromycin at different gestational stages [(gestational day, GD) 10–12 or GD 15–17], doses (50, 100, or 200 mg/kg·d), and courses (single or multiple). On GD 18, we collected offspring blood and ovaries to examine changes in fetal serum estradiol (E2) levels, fetal ovarian morphology, pre-granulosa cell function, and oocyte development. Multiple courses of PAzE resulted in abnormal fetal ovarian morphological development, disorganized germ cell nests, enhanced ovarian cell proliferation, and reduced apoptosis. Simultaneously, multiple courses of PAzE significantly increased fetal serum E2 levels, elevated ovarian steroidogenic function (indicated by Star, 3β-hsd, and Cyp19 expression), disrupted oocyte development (indicated by Figlα and Nobox expression), and led to alterations in the MAPK signal pathway in fetal ovaries, particularly in the high-dose treatment group. In contrast, a single course of PAzE reduced fetal ovarian cell proliferation, decreased steroidogenic function, and inhibited oocyte development, particularly through the downregulation of Mek2 expression in the MAPK signal pathway. These findings suggest that PAzE can influence various aspects of fetal mouse ovarian cell development. Multiple courses enhance pre-granulosa cell estrogen synthesis function and advance germ cell development, while a single terminal gestation dose inhibits germ cell development. These differential effects may be associated with changes in the MAPK signal pathway

Stereoselective Synthesis of Functionalized Tetrahydro‑1<i>H</i>‑1,2-diazepines by <i>N</i>‑Heterocyclic Carbene-Catalyzed [3 + 4] Annulation

An efficient <i>N</i>-heterocyclic carbene (NHC)-catalyzed asymmetric [3 + 4] annulation reaction of <i>N</i>-Ts hydrazones with 2-bromoenals has been developed. A series of functionalized tetrahydro-1<i>H</i>-1,2-diazepines with two consecutive stereocenters was obtained using NHCs as the catalyst in good yields with excellent diastereo- and enantioselectivities