Given the increasing concern regarding antibacterial resistance, the antimicrobial properties of naphthoquinones have recently attracted significant attention. While 1,4-naphthoquinone and its derivatives have been extensively studied, the antibacterial properties of 5,8-dihydroxy-1,4-naphthoquinone derivatives remain relatively unexplored. This study presents a comprehensive in vitro and in vivo analysis of the antibacterial activity of 35 naturally sourced and chemically synthesized derivatives of 5,8-dihydroxy-1,4-naphthoquinone. Kirby-Bauer antibiotic testing identified three compounds with activity against methicillin-resistant Staphylococcus aureus (MRSA), with one compound (PNP-02) demonstrating activity comparable to vancomycin in minimum inhibitory concentration, minimum bactericidal concentration (MBC), and time-kill assays. Microscopic and biochemical analyses revealed that PNP-02 adversely affects the cell wall and cell membrane of MRSA. Mechanistic investigations, including proteomic sequencing analyses, Western blotting, and RT-qPCR assays, indicated that PNP-02 compromises cell membrane integrity by inhibiting arginine biosynthesis and pyrimidine metabolism pathways, thereby increasing membrane permeability and inducing bacterial death. In an in vivo mouse model of skin wound healing, PNP-02 exhibited antibacterial efficacy similar to vancomycin. The compound demonstrated low toxicity to cultured human cells and in hemolysis assays and remained stable during serum incubation. These findings suggest that PNP-02 possesses promising bioactivity against MRSA and represents a potential novel antibacterial agent.
Methicillin-Resistant Staphylococcus aureus/genetics* ; Anti-Bacterial Agents/chemistry* ; Naphthoquinones/administration & dosage* ; Animals ; Microbial Sensitivity Tests ; Mice ; Humans ; Staphylococcal Infections/microbiology* ; Molecular Structure

SoxR, one of bacterial transcriptional regulators, plays a crucial role in bacterial responses to oxidative stress induced by unfavorable environmental conditions. So far, the understanding of bacterial responses to oxidative stress mainly stems from a handful model bacteria such as Escherichia coli and the studies on non-model bacterial responses to oxidative stress are limited. In this study, Citrobacter braakii JPG1, a commonly occurring strain of enterobacteria, was used as a model for the first time to explore the role of SoxR in the responses to aerobic/anaerobic-menadione stress. First, we analyzed the phylogenetic relationship of SoxR based on the whole genome and constructed the soxR-deleted strain (ΔsoxR). Then, the cell counts of the wild type (WT) and ΔsoxR were compared under aerobic/anaerobic-menadione stress. The results showed that the cell count of WT exposed to the aerobic-low concentration menadione (0.1 mmol/L) stress for 24 h increased by 4.2 times compared with that at the time point of 0 h, while that of ΔsoxR only increased by 1.3 times. The vast majority of WT and ΔsoxR cells died after exposure to the aerobic-high concentration menadione (0.3 mmol/L) stress for 24 h, with the cell counts only 29% and 0.2% of those at the time point of 0 h, respectively. Interestingly, the cell counts of WT showed no significant difference between the anaerobic-menadione stress and the control (P > 0.05), and the same was true for ΔsoxR. All these results indicated that SoxR of C. braakii JPG1 only has a regulatory effect on the redox cycling compound menadione under aerobic conditions and enhance the antioxidant capacity. Under anaerobic conditions, menadione failed to activate SoxR. The findings from this study provide new insights into understanding both the physiological responses to menadione stress and the regulatory role of SoxR under different oxygen conditions.
Bacterial Proteins/physiology* ; Anaerobiosis ; Aerobiosis ; Vitamin K 3/pharmacology* ; Citrobacter/metabolism* ; Transcription Factors/physiology* ; Oxidative Stress ; Gene Expression Regulation, Bacterial

Humans ; Vitamins/therapeutic use* ; Iron, Dietary ; Diabetes Mellitus, Type 2 ; Nutrition Surveys ; Diet ; Vitamin A ; Vitamin K

Functional membrane microdomains (FMMs) that are mainly composed of scaffold proteins and polyisoprenoids play important roles in diverse cellular physiological processes in bacteria. The aim of this study was to identify the correlation between MK-7 and FMMs and then regulate the MK-7 biosynthesis through FMMs. Firstly, the relationship between FMMs and MK-7 on the cell membrane was determined by fluorescent labeling. Secondly, we demonstrated that MK-7 is a key polyisoprenoid component of FMMs by analyzing the changes in the content of MK-7 on cell membrane and the changes in the membrane order before and after destroying the integrity of FMMs. Subsequently, the subcellular localization of some key enzymes in MK-7 synthesis was explored by visual analysis, and the intracellular free pathway enzymes Fni, IspA, HepT and YuxO were localized to FMMs through FloA to achieve the compartmentalization of MK-7 synthesis pathway. Finally, a high MK-7 production strain BS3AT was successfully obtained. The production of MK-7 reached 300.3 mg/L in shake flask and 464.2 mg/L in 3 L fermenter.
Bacillus subtilis/metabolism* ; Vitamin K 2/metabolism* ; Bioreactors/microbiology* ; Membrane Microdomains/metabolism*

OBJECTIVE: To observe the expression of c-Myc protein in cervical cancer HeLa cells and explore the effect of juglone on the proliferation and apoptosis of HeLa cells by affecting c-Myc ubiquitination. METHODS: HeLa cells treated with different concentrations (0, 10, 20, or 50 μmol/L) of juglone or with 20 μmol/L juglone for different time lengths were examined for expression of c-Myc protein with Western blotting. The half-life of c-Myc protein was determined using cycloheximide (CHX) and c-Myc protein degradation was detected using coimmunoprecipitation. We also assessed the effects of 20 μmol/L juglone combined with 0, 1.0 or 2.0 μmol/L MG132 (a proteasome inhibitor) on c-Myc expression. The effects of 20 μmol/L juglone on the proliferation and apoptosis of HeLa cells with RNA interference-mediated knockdown of c-Myc were evaluated with MTT assay and flow cytometry. RESULTS: Treatment with juglone significantly lowered c-Myc protein expression in HeLa cells in a concentration-and time-dependent manner (P < 0.05). Juglone obviously shortened the half-life of c-Myc protein, and the addition of MG132 significantly up-regulated the expression level of c-Myc protein (P < 0.05). Juglone treatment also promoted ubiquitination of c-Myc protein in HeLa cells. Compared with the cells transfected with a negative control construct, the cells transfected with si-c-Myc showed significantly decreased proliferation inhibition and a lowered cell rate with early apoptosis after juglone treatment (P < 0.05). CONCLUSION Juglone inhibits proliferation and promotes apoptosis of HeLa cells by affecting the ubiquitination of c-Myc protein.
Apoptosis ; Cell Proliferation ; Female ; HeLa Cells ; Humans ; Naphthoquinones ; Ubiquitination ; Uterine Cervical Neoplasms/genetics*

OBJECTIVES: To study the level of serum vitamin K₂ (VitK₂) and its association with bone metabolism markers osteocalcin (OC), type I procollagen amino-terminal peptide (PINP), and type I collagen carboxy-terminal peptide (CTX) in children. METHODS: A prospective analysis was performed on 1 732 children who underwent routine physical examination from October 2020 to October 2021. The serum levels of VitK₂ and 25-hydroxy vitamin D [25(OH)D] were measured. According to age, they were divided into four groups: <1 year, 1-3 years group, >3-6 years group, and >6-14 years. A total of 309 children with 25(OH)D≥50 nmol/L were screened out, and serum levels of OC, PINP, and CTX were measured to investigate the correlation of the serum levels of OC, PINP, and CTX with serum VitK₂ levels in different age groups. RESULTS: The prevalence rate of serum VitK₂ deficiency was 52.31% (906/1 732). The VitK₂ deficiency group had higher prevalence rates of overweight/obesity and growth pain (≥3 years of age) than the normal VitK₂ group (P<0.05). There were differences in the prevalence rate of serum VitK₂ deficiency (P<0.0083) and the serum level of VitK₂ (P<0.05) between the 1-3 years group and the >6-14 years group. The <1 year group had a higher serum level of CTX and a lower serum level of PINP than the >3-6 years group and the >6-14 years group (P<0.05). The <1 year group had a lower serum level of OC than the >6-14 years group (P<0.05). Serum VitK₂ level was positively correlated with OC level (r_s=0.347, P<0.01), and CTX level was negatively correlated with PINP level (r_s=-0.317, P<0.01). CONCLUSIONS Serum VitK₂ deficiency may be associated with overweight/obesity. Serum VitK₂ may affect the level of OC and even bone health.
Child ; Humans ; Infant ; Biomarkers/metabolism* ; Collagen Type I/metabolism* ; Obesity/complications* ; Osteocalcin/metabolism* ; Overweight/complications* ; Peptide Fragments/metabolism* ; Peptides/metabolism* ; Procollagen/metabolism* ; Vitamin K/blood* ; Child, Preschool ; Adolescent ; Bone and Bones/metabolism*

Administration, Oral ; Humans ; Infant, Newborn ; Vitamin K

OBJECTIVE: To investigate the effect of atovaquone on the cell cycle and apoptosis of non-Hodgkin's lymphoma Raji cells, and clarify the related mechanisms. METHODS: MTT assay and trypan blue dye exclusion method were used to evaluate the effect of atovaquone on the proliferation of Raji cells. After the cells were stained by PI staining, the cell cycle distribution was detected by flow cytometry. Cell apoptosis was analyzed by Annexin V/PI double binding assay. The intracellular alterations of reactive oxygen species were detected by 2', 7'-dichlorofluorescein diacetate (DCFH-DA). The protein expression of cell cycle and apoptosis related molecules were detected by Western blot. RESULTS: Various concentrations of atovaquone (5-40 μmol/L) inhibited the growth of Raji cells in a concentration-dependent manner (r=0.951). The proliferation of Raji cells was significantly inhibited after treated by atovaquone (20 and 30 μmol/L) for 24, 48 and 72 h, which showed statistically different with that in the control group (P<0.01, P<0.001, P<0.001). G₁ phase arrest (P<0.01, P<0.001) and apoptosis (P<0.01) of Raji cells was induced by atovaquone (20 and 30 μmol/L) significantly for 24 h and 48 h, respectively. The expression of p-JAK2 and p-STAT3(Y705) protein were down-regulated significantly induced by atovaquone (P<0.001, P<0.05). Furthermore, atovaquone treatment could induce the decreasing of antiapoptotic protein Mcl-1, Bcl-2, and Bcl-xl expression level (P<0.05) and increasing of cleaved caspase-3 protein expression level. In addition, atovaquone could also induce the down-regulation of c-Myc (P<0.001, P<0.01) and cell cycle related molecules Cyclin D1, CDK4, and CDK6 (P<0.01, P<0.05) protein expression. CONCLUSION Atovaquone effectively inhibits cell proliferation and induces cell cycle arrest and apoptosis by suppression of STAT3 signaling pathway in Raji cells. It can be a potential therapeutic agent against non-Hodgkin's lymphoma.
Humans ; Atovaquone/pharmacology* ; Cell Cycle Checkpoints ; Apoptosis ; Lymphoma, Non-Hodgkin

OBJECTIVE: To verrify the anti-tumor efficacy and toxicity between juglone (Jug) and Jug-loaded PLGA nanoparticles (Jug-PLGA-NPs). METHODS: Jug-PLGA-NPs were prepared by ultrasonic emulsification. The anti-tumor activity of Jug (2, 3, 4 µg/mL) and Jug-PLGA-NPs (Jug: 2, 3, 4 µg/mL) in vitro was measured by MTT assay and cell apoptosis analysis. The distribution, anti-tumor effect and biological safety in vivo was evaluated on A375 nude mice. RESULTS: With the advantage of good penetration and targeting properties, Jug-PLGA-NPs significantly inhibited proliferation and migration of melanoma cells both in vitro and in vivo (P<0.05 or P<0.01) with acceptable biocompatibility. CONCLUSIONS Jug can inhibit the growth of melanoma but is highly toxic. With the advantage of sustained release, tumor targeting, anti-tumor activity and acceptable biological safety, Jug-PLGA-NPs provide a new pharmaceutical form for future application of Jug.
Animals ; Cell Line, Tumor ; Delayed-Action Preparations/therapeutic use* ; Drug Carriers/therapeutic use* ; Melanoma/pathology* ; Mice ; Mice, Nude ; Nanoparticles ; Naphthoquinones ; Particle Size ; Polylactic Acid-Polyglycolic Acid Copolymer/therapeutic use*

Bromadiolone, commonly known as super warfarin, is a long-acting coumarin dicoumarin rodenticide. The mechanism of bromadiolone is mainly to inhibit vitamin K1 epoxide reductase and affect the synthesis of coagulation factors Ⅱ, Ⅶ, Ⅸ and Ⅹ, which causes blood coagulation dysfunction and systemic multiple organ hemorrhage. Here, we report of a case of bromadiolone poisoning patient who had digestive tract, abdominal hemorrhage, as well as secondary paralytic ileus. After blood product transfusion and vitamin K1 supplementation, the patient was discharged after the physical condition was improved. It's suggestied that clinicians should pay attention to rare complications to prevent missed diagnosis when treating other bromadiolone poisoning.
4-Hydroxycoumarins ; Blood Coagulation Factors ; Dicumarol ; Hemorrhage ; Humans ; Intestinal Pseudo-Obstruction/chemically induced* ; Oxidoreductases ; Rodenticides ; Vitamin K 1 ; Warfarin