Search

Aim: The relationship between the gut microbiota, metabolites and body fat percentage (BFP) remains unexplored. We systematically assessed the causal relationships between gut microbiota, metabolites and BFP using Mendelian randomization analysis. Materials and Methods: Single nucleotide polymorphisms associated with gut microbiota, blood metabolites and BFP were screened via a genome‐wide association study enrolling individuals of European descent. Summary data from genome‐wide association studies were extracted from the MiBioGen consortium and the UK Biobank. The inverse variance‐weighted model was the primary method used to estimate these causal relationships. Sensitivity analyses were performed using pleiotropy, Mendelian randomization‐Egger regression, heterogeneity tests and leave‐one‐out tests. Results: In the aspect of phyla, classes, orders, families and genera, we observed that o_Bifidobacteriales [β = −0.05; 95% confidence interval (CI): −0.07 to −0.03; false discovery rate (FDR) = 2.76 × 10−3], f_Bifidobacteriaceae (β = −0.05; 95% CI: −0.07 to −0.07; FDR = 2.76 × 10−3), p_Actinobacteria (β = −0.06; 95% CI: −0.09 to −0.03; FDR = 6.36 × 10−3), c_Actinobacteria (β = −0.05; 95% CI: −0.08 to −0.02; FDR = 1.06 × 10−2), g_Bifidobacterium (β = −0.05; 95% CI: −0.07 to −0.02; FDR = 1.85 × 10−2), g_Ruminiclostridium9 (β = −0.03; 95% CI: −0.06 to −0.01; FDR = 4.81 × 10−2) were negatively associated with BFP. G_Olsenella (β = 0.02; 95% CI: 0.01‐0.03; FDR = 2.16 × 10−2) was positively associated with BFP. Among the gut microbiotas, f_Bifidobacteriales, o_Bifidobacteriales, c_Actinobacteria and p_Actinobacteria were shown to be significantly associated with BFP in the validated dataset. In the aspect of metabolites, we only observed that valine (β = 0.77; 95% CI: 0.5‐1.04; FDR = 8.65 × 10−6) was associated with BFP. Conclusions: Multiple gut microbiota and metabolites were strongly associated with an increased BFP. Further studies are required to elucidate the mechanisms underlying this putative causality. In addition, BFP, a key indicator of obesity, suggests that obesity‐related interventions can be developed from gut microbiota and metabolite perspectives. [ABSTRACT FROM AUTHOR]

Introduction: The emergence of multidrug-resistant Klebsiella pneumoniae (K. pneumoniae) and the decline of effective antibiotics lead to the urgent need for new antibacterial agents. The aim of this study is to investigate the therapeutic effect of antimicrobial peptides against gentamicin-resistant (RT) K. pneumoniae and to screen effective antimicrobial peptides. Methods: In this study, the RT strains were induced by gradient gentamicin, and the RT strains were selected by detecting the expression levels of efflux pump genes, porin genes, and biofilm formation genes of the strains combined with their effects on the cells. Then the effects of four antimicrobial peptides on the efflux pump activity, biofilm formation level and cell condition after infection were detected to explore the effects of antimicrobial peptides on RT strains. Finally, the RT strain was used to induce a mouse model of pneumonia, and the four antimicrobial peptides were used to treat pneumonia mice for in vivo experiments. The pathological changes in lung tissues in each group were detected to explore the antimicrobial peptide with the most significant effect on the RT strain in vivo. Results: The results showed that the minimal inhibitory concentrations of the RT strains (strain C and strain I) were significantly higher than those of the wild-type strain, and the expression of efflux pump, porin and biofilm formation genes was significantly increased. The antimicrobial peptides could effectively inhibit the biofilm formation and efflux pump protein function of the RT strains. In addition, the antimicrobial peptides showed promising antibacterial effects both in vitro and in vivo. Discussion: Our study provided a theoretical basis for the treatment of gentamicin resistant K. pneumoniae infection with antimicrobial peptides, and found that KLA was significantly superior to LL37, Magainin I, KLA and Dermaseptin (10 μg/mL in cells, 50 μg in mice). [ABSTRACT FROM AUTHOR]

Helianthus annuus seed byproduct is a residual product obtained after seed oil extraction. The present study investigated the preventive and repair effects of the H. annuus seed byproduct ethanol extract (HSE) on ultraviolet radiation (UVR)‐induced injury in human immortalized keratinocytes (HaCaTs) and human skin fibroblasts (HSFs). Results revealed that the total phenolic acid and oligosaccharide content in HSE was >50%. HSE had a stronger preventive effect on UVR‐induced injury than the repair effect. Moreover, phenolic acids were the main active component of HSE mediating the preventative effect. In HaCaTs and HSFs, HSE prevented UVR‐induced injury by inhibiting excessive ROS production. It reduced the secretion of tumor necrosis TNF‐α, IL‐1α, IL‐1β, IL‐6, and IL‐8 by inhibiting the level of ROS, thus reducing inflammation‐mediated injury to skin cells. In addition, HSE inhibited the expression of various mRNA kinases in the MAPK–ERK/p38/JNK pathway. This downregulated the expression of activator protein‐1 (AP‐1) mRNA and further reduced the secretion of matrix metalloproteinase (MMP)‐1, MMP‐3, and MMP‐9 as well as reduced UVR‐induced injury to the cells. In conclusion, HSE is a broad‐spectrum, natural UV filter with high efficiency and low toxicity that has the potential to be used in sunscreen products. [ABSTRACT FROM AUTHOR]

The existing reservoir in the Yongjin block exhibits an extremely low matrix permeability, posing challenges in precisely evaluating the damage caused by fracturing fluid using traditional core flow experimental methods. Currently, there is no established quantitative method for characterizing the degree of damage. In this study, we integrated online nuclear magnetic resonance, microscopic computed tomography, and core displacement experimental techniques, pioneering a novel approach to evaluate damage in deep tight oil reservoirs subjected to hydraulic fracturing. We analyzed the influence patterns of key factors such as backflow pressure differential, shut-in time, invasion volume, and residual retention on rock matrix damage in the operational area. The study unveiled the mechanisms behind water sensitivity, water block, and fracturing fluid retention damage among oil, water, and rock. The results indicate that water sensitivity damage is less than 20%, primarily occurring within large pores. Water block damage can significantly reduce the residual oil permeability. Experimental findings suggest that optimizing liquid backflow with a pressure differential and well shut-in time set at 5 MPa and 9 days can markedly reduce the intrusion volume of gel-breaking fluid, restoring the residual oil permeability. Under high-pressure differential conditions, residual fracturing fluid can infiltrate the rock matrix, resulting in pore damage. Additionally, it can accumulate on the fracture surfaces, thereby reducing the permeability of microfractures. [ABSTRACT FROM AUTHOR]