Rapid classification and identification of chemical constituents in Leonurus japonicus Houtt based on UPLC-Q-Orbitrap-MS combined with data post-processing techniques.

Leonurus japonicus Houtt (LJH) is a bulk medicinal material commonly used in clinical practice, but its complex constituents have not been completely understood, posing challenges to pharmacology, pharmacokinetic research, and scientific and rational drug use. As a result, it is critical to develop an efficient and accurate method for classifying and identifying the chemical composition of LJH. In this study, ultra-performance liquid chromatography-quadrupole electrostatic field-orbital trap high resolution mass spectrometry (UPLC-Q-Orbitrap-MS) was successfully established, along with two data post-processing techniques, characteristic fragmentations (CFs) and neutral losses (NLs), to quickly classify and identify the chemical constituents in LJH. As a result, 44 constituents of LJH were identified, including four alkaloids, 20 flavonoids, two phenylpropanoids, 17 organic acids, and one amino acid. The method in this paper enables classification and identification of chemical compositions rapidly, providing a scientific foundation for further research on the effective and toxic substances of LJH.

A novel lytic bacteriophage against colistin-resistant Escherichia coli isolated from different animals.

Escherichia coli is a common pathogen in human and veterinary clinical infection. With antibiotic resistance including colistin resistance increasing globally, few antibiotic treatments are available for use against multidrug-resistant strains of E. coli. Given such circumstances, bacteriophage (phage) therapy is once again being considered as a potential alternative or adjunct to antibiotic therapy. Here, we isolated 52 phages from 816 samples from pig, chicken and duck farms in 4 provinces in China and identified a novel Escherichia phage, vB_EcoStr-FJ63A, from pig feces. Morphological observation showed that phage vB_EcoStr-FJ63A had an icosahedral capsid and an inflexible tail. Whole-genome sequencing revealed a double-stranded DNA genome of 168,157 bp (including 271 coding sequences) with a GC content of 40.29%. Bioinformatic analysis classified phage vB_EcoStr-FJ63A as a Krischvirus, belonging to Straboviridae. The phage was relatively stable at pH 4-10 and below 60℃. It was lytic against a wide variety of colistin-resistant strains of E. coli from various animals, with one-step growth curves showing a latent period of 30 min and burst size of ∼11 PFU per infected cell. Maximum bactericidal activity was achieved within 2 h. No antibiotic resistance or virulence genes were detected in the phage genome. Further studies are warranted to develop phage vB_EcoStr-FJ63A as a potential biocontrol agent against colistin-resistant E. coli.

Mifepristone Treatment in Pregnant Murine Model Induced Mammary Gland Dysplasia and Postpartum Hypogalactia.

Mammary gland dysplasia and postpartum hypogalactia often occur in humans and in the livestock breeding industry. However, their underlying mechanisms are not clear yet. Mifepristone, which has a high affinity for progesterone (P4) and glucocorticoid receptors, was exploited here to induce the disorders of mammary gland development and lactation. Four strategies were devised for treating pregnant mice with mifepristone. In the first strategy, mice were administered 1.20 mg mifepristone/kg body weight (BW) on pregnancy day 4 (Pd4). In the second strategy, mifepristone was administered to mice twice, with 1.20 mg/kg BW on Pd4 and 0.40 mg/kg BW on Pd8. In the third strategy, mice were treated with a single dose of 0.40 mg mifepristone/kg BW on Pd8. In the fourth strategy, mice were administered 0.40 mg mifepristone/kg BW on Pd8 and 0.20 mg mifepristone/kg BW on Pd12. The results suggested that mifepristone administration at the dose of 1.20 mg/kg BW on Pd4 caused significant reduction in milk production on lactation day 1 (Ld1), Ld2, and Ld3, as assessed using a weigh-suckle-weigh assay. Mammary ß-casein expression, milk yields, litter growth rates, gland structure, and serum concentrations of 17-ß estrogen (E2), P4, prolactin (PRL), growth hormone (GH), corticosterone (CORT) and oxytocin (OT) as well as the receptors of these hormones were determined during pregnancy or lactation after performing the first (Pd4) strategy. The results demonstrated that mifepristone administration during early pregnancy decreased ß-casein expression, milk yields and litter growth rates, induced fewer alveoli, enlarged alveolar lumina, and altered the levels of E2, P4, PRL, GH, CORT, and OT as well as the mRNA expression of these hormonal receptors during pregnancy or early lactation. The present study on pregnant mice treated with mifepristone offers an innovative murine model to study the mechanism underlying mammary gland dysplasia and postpartum hypogalactia.