To explore the effect and underlying mechanism of increased expression of M-type phospholipase A
receptor (PLA
R) on podocyte membrane induced by hepatitis B virus X protein (HBx) on podocyte ...pyroptosis in hepatitis B virus-associated glomerulonephritis (HBV-GN).
Transfection of the HBx gene into human kidney podocytes was used to mimic the HBV-GN pathogenesis process. Subsequently, podocytes were divided into the following eight groups: normal control plus secretory phospholipase A
-ⅠB (sPLA
-ⅠB) group, empty plasmid plus sPLA
-ⅠB group, HBx group, HBx plus sPLA
-ⅠB group, HBx plus sPLA
-ⅠB plus PLA
R control siRNA group, HBx plus sPLA
-ⅠB plus PLA
R-siRNA group, HBx plus sPLA
-ⅠB plus ROS control siRNA group, and HBx plus sPLA
-ⅠB plus ROS-siRNA group. Podocyte morphology was observed under a transmission electron microscope, and PLA
R expression was detected under a fluorescence microscope. Podocyte pyroptosis and reactive oxygen species (ROS) expression were analyzed by flow cytometry, and the mRNA and pr
Reported infection rates following anterior cruciate ligament (ACL) reconstruction are low, but infections are associated with high morbidity including reoperations and inferior clinical outcomes. ...The purpose of the current study was to investigate the rate of infection after ACL reconstruction with and without graft preparation with a vancomycin irrigant.
All ACL reconstructions performed between May 2009 and August 2018 at a single academic institution were reviewed and categorized based on vancomycin use. Patients with <90-day follow-up, intraoperative graft preparation with an antibiotic other than vancomycin, or previous ipsilateral knee infection were excluded. Infection was defined as a return to the operating room for irrigation and debridement within 90 days after ACL reconstruction. Descriptive and inferential statistical analysis using t tests and Poisson regression were performed, with significance defined as p < 0.05.
In total, 1,640 patients (952 males; 58.0%) with a mean age (and standard deviation) of 27.7 ± 11.4 years underwent ACL reconstruction (1,379 primary procedures; 84.1%) and were included for analysis. Intraoperative vancomycin was used in 798 cases (48.7%), whereas 842 ACL reconstructions (51.3%) were performed without intraoperative vancomycin. In total, 11 reconstructions (0.7%) were followed by infection, which occurred in 10 (1.2%) of the patients in whom the graft was not soaked in vancomycin and in 1 (0.1%) of the patients in whom the graft was soaked in vancomycin (p = 0.032). Age (p = 0.571), sex (p = 0.707), smoking (p = 0.407), surgeon (p = 0.124), and insurance type (p = 0.616) were not associated with postoperative infection risk. Autograft use was associated with decreased infections (p = 0.045). There was an 89.4% relative risk reduction with the use of intraoperative vancomycin. An increased body mass index (BMI) (p = 0.029), increased operative time (p = 0.001), and the absence of ACL graft preparation with vancomycin (p = 0.032) independently predicted postoperative infection.
The use of vancomycin-soaked grafts was associated with a 10-fold reduction in infection after ACL reconstruction (0.1% versus 1.2%; p = 0.032). Other risk factors for infection after ACL reconstruction included increased BMI and increased operative time.
Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
Enterococci have evolved resistance mechanisms to protect their cell envelopes against bacteriocins and host cationic antimicrobial peptides (CAMPs) produced in the gastrointestinal environment. ...Activation of the membrane stress response has also been tied to resistance to the lipopeptide antibiotic daptomycin. However, the actual effectors mediating resistance have not been elucidated. Here, we show that the MadRS (formerly YxdJK) membrane antimicrobial peptide defense system controls a network of genes, including a previously uncharacterized three gene operon (madEFG) that protects the E. faecalis cell envelope from antimicrobial peptides. Constitutive activation of the system confers protection against CAMPs and daptomycin in the absence of a functional LiaFSR system and leads to persistence of cardiac microlesions in vivo. Moreover, changes in the lipid cell membrane environment alter CAMP susceptibility and expression of the MadRS system. Thus, we provide a framework supporting a multilayered envelope defense mechanism for resistance and survival coupled to virulence.
Aims: 1-Aminocyclopropane-1-carboxylate (ACC) deaminase activity is an efficient marker for bacteria to promote plant growth by lowering ethylene levels in plants. We aim to develop a method for ...rapidly screening bacteria containing ACC deaminase, based on a colorimetric ninhydrin assay of ACC. Methods and Results: A reliable colorimetric ninhydrin assay was developed to quantify ACC using heat-resistant polypropylene chimney-top 96-well PCR plates, having the wells evenly heated in boiling water, preventing accidental contamination from boiling water and limiting evaporation. With this method to measure bacterial consumption of ACC, 44 ACC-utilizing bacterial isolates were rapidly screened out from 311 bacterial isolates that were able to grow on minimal media containing ACC as the sole nitrogen source. The 44 ACC-utilizing bacterial isolates showed ACC deaminase activities and belonged to the genus Burkholderia, Pseudomonas or Herbaspirillum. Conclusions: Determination of bacterial ACC consumption by the PCR-plate ninhydrin-ACC assay is a rapid and efficient method for screening bacteria containing ACC deaminase from a large number of bacterial isolates. Significance and Impact of the Study: The PCR-plate ninhydrin-ACC assay extends the utility of the ninhydrin reaction and enables a rapid screening of bacteria containing ACC deaminase from large numbers of bacterial isolates.
Carbapenem-resistant Klebsiella pneumoniae (CR
) is an urgent public health threat. Worldwide dissemination of CR
has been largely attributed to clonal group (CG) 258. However, recent evidence ...indicates the global emergence of a CR
CG307 lineage. Houston, TX, is the first large city in the United States with detected cocirculation of both CR
CG307 and CG258. We sought to characterize the genomic and clinical factors contributing to the parallel endemic spread of CG258 and CG307. CR
isolates were collected as part of the prospective, Consortium on Resistance against Carbapenems in Klebsiella and other
2 (CRACKLE-2) study. Hybrid short-read and long-read genome assemblies were generated from 119 CR
isolates (95 originated from Houston hospitals). A comprehensive characterization of phylogenies, gene transfer, and plasmid content with pan-genome analysis was performed on all CR
isolates. Plasmid mating experiments were performed with CG307 and CG258 isolates of interest. Dissection of the accessory genomes suggested independent evolution and limited horizontal gene transfer between CG307 and CG258 lineages. CG307 contained a diverse repertoire of mobile genetic elements, which were shared with other non-CG258 K. pneumoniae isolates. Three unique clades of Houston CG307 isolates clustered distinctly from other global CG307 isolates, indicating potential selective adaptation of particular CG307 lineages to their respective geographical niches. CG307 strains were often isolated from the urine of hospitalized patients, likely serving as important reservoirs for genes encoding carbapenemases and extended-spectrum β-lactamases. Our findings suggest parallel cocirculation of high-risk lineages with potentially divergent evolution.
The prevalence of carbapenem-resistant Klebsiella pneumoniae (CR
) infections in nosocomial settings remains a public health challenge. High-risk clones such as clonal group 258 (CG258) are particularly concerning due to their association with
carriage, which can severely complicate antimicrobial treatments. There is a recent emergence of clonal group 307 (CG307) worldwide with little understanding of how this successful clone has been able to adapt while cocirculating with CG258. We provide the first evidence of potentially divergent evolution between CG258 and CG307 with limited sharing of adaptive genes. Houston, TX, is home to the largest medical center in the world, with a large influx of domestic and international patients. Thus, our unique geographical setting, where two pandemic strains of CR
are circulating, provides an indication of how differential accessory genome content can drive stable, endemic populations of CR
. Pan-genomic analyses such as these can reveal unique signatures of successful CR
dissemination, such as the CG307-associated plasmid (pCG307_HTX), and provide invaluable insights into the surveillance of local carbapenem-resistant
(CRE) epidemiology.
Objective:
In the intensive care unit (ICU), prolonged inactivity is common, increasing patients’ risk for adverse outcomes, including ICU-acquired weakness. Hence, interventions to minimize ...inactivity are gaining popularity, highlighting actigraphy, a measure of activity involving a wristwatch-like accelerometer, as a method to inform these efforts. Therefore, we performed a systematic review of studies that used actigraphy to measure patient activity in the ICU setting.
Data Sources:
We searched PubMed, EMBASE, CINAHL, Cochrane Library, and ProQuest from inception until December 2016.
Study Selection:
Two reviewers independently screened studies for inclusion. A study was eligible for inclusion if it was published in a peer-reviewed journal and used actigraphy to measure activity in ≥5 ICU patients.
Data Extraction:
Two reviewers independently performed data abstraction and risk of bias assessment. Abstracted actigraphy-based activity data included total activity time and activity counts.
Results:
Of 16 studies (607 ICU patients) identified, 14 (88%) were observational, 2 (12%) were randomized control trials, and 5 (31%) were published after 2009. Mean patient activity levels per 15 to 60 second epoch ranged from 25 to 37 daytime and 2 to 19 nighttime movements. Actigraphy was evaluated in the context of ICU and post-ICU outcomes in 11 (69%) and 5 (31%) studies, respectively, and demonstrated potential associations between actigraphy-based activity levels and delirium, sedation, pain, anxiety, time to extubation, and length of stay.
Conclusion:
Actigraphy has demonstrated that patients are profoundly inactive in the ICU with actigraphy-based activity levels potentially associated with important measures, such as delirium, sedation, and length of stay. Larger and more rigorous studies are needed to further evaluate these associations and the overall utility of actigraphy in the ICU setting.
Calcium plays an essential role in plant developmental process, especially in pollen tube growth. Verapamil, an inhibitor of calcium channels, could affect extracellular calcium ion influx. The ...present study aimed to investigate the effect of verapamil on pollen tube growth of
Malus domestica
and the possible cytological mechanism. Results showed that verapamil affected pollen germination and tube growth in a dose dependent manner. 20 μM verapamil promoted pollen germination and tube growth, while 700 μM verapamil inhibited pollen germination and tube growth. Results from non-invasive ion-selective electrode technique and fluorescent labeling showed that 700 μM verapamil decreased calcium influx and disturbed Ca
2+
c gradient at pollen tube apex. In addition, 700 μM verapamil also affected actin filaments. Further results demonstrated that 700 μM verapamil influenced distribution of pollen tube wall components such as callose, acid pectins and esterified pectins, Fourier-transform infrared analysis (FTIR) of chemical composition supported the above results. In summary, 700 μM verapamil triggered multiple cellular changes including Ca
2+
influx, Ca
2+
c gradient, actin filaments and pollen tube wall components. Based on the above results, we speculated that 700 μM verapamil inhibited apical growth of pollen tubes through altering Ca
2+
influx, Ca
2+
c gradient, actin filaments and cell wall components.
Abstract
Background
Heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) compromise the clinical efficacy of vancomycin. The hVISA isolates spontaneously produce ...vancomycin-intermediate Staphylococcus aureus (VISA) cells generated by diverse and intriguing mechanisms.
Objective
To characterize the biomolecular profile of clinical hVISA applying genomic, transcriptomic and metabolomic approaches.
Methods
39 hVISA and 305 VSSA and their genomes were included. Core genome-based Bayesian phylogenetic reconstructions were built and alterations in predicted proteins in VISA/hVISA were interrogated. Linear discriminant analysis and a Genome-Wide Association Study were performed. Differentially expressed genes were identified in hVISA-VSSA by RNA-sequencing. The undirected profiles of metabolites were determined by liquid chromatography and hydrophilic interaction in six CC5-MRSA.
Results
Genomic relatedness of MRSA associated to hVISA phenotype was not detected. The change Try38 → His in Atl (autolysin) was identified in 92% of the hVISA. We identified SNPs and k-mers associated to hVISA in 11 coding regions with predicted functions in virulence, transport systems, carbohydrate metabolism and tRNA synthesis. Further, capABCDE, sdrD, esaA, esaD, essA and ssaA genes were overexpressed in hVISA, while lacABCDEFG genes were downregulated. Additionally, valine, threonine, leucine tyrosine, FAD and NADH were more abundant in VSSA, while arginine, glycine and betaine were more abundant in hVISA. Finally, we observed altered metabolic pathways in hVISA, including purine and pyrimidine pathway, CoA biosynthesis, amino acid metabolism and aminoacyl tRNA biosynthesis.
Conclusions
Our results show that the mechanism of hVISA involves major changes in regulatory systems, expression of virulence factors and reduction in glycolysis via TCA cycle. This work contributes to the understanding of the development of this complex resistance mechanism in regional strains.
•The glass forming ability is the largest for the Zr-based alloy with 0.3 at% Ti.•The glass transition temperature is decreased by the Ti addition.•the supercooled liquid region is increased by the ...Ti addition.•Both strength and plasticity are significantly enhanced by the Ti addition.•The corrosion current density increases with increasing Ti content.
(Zr54Al10.2Ni9.4Cu26.4)100−xTix (x = 0–0.5, at%) bulk metallic glasses were prepared by water-cooled copper suction casting method. The Ti microalloying effect on glass forming ability and physical and chemical properties of Zr54Al10.2Ni9.4Cu26.4 glass forming alloy were systematically investigated. The glass forming ability is the largest for the Zr-based alloy with 0.3 at% Ti. The glass transition temperature is decreased by the Ti addition, while the supercooled liquid region is broadened. Both strength and plasticity are significantly enhanced by the Ti addition. The yield strength and the fracture strength firstly increase and then decrease when the Ti content reaches up to 0.3 at%. The plastic strain and the fracture strain increase with increasing Ti content. In addition, the corrosion potential is slightly decreased by the Ti addition. The corrosion current density increases with increasing Ti content. The pitting corrosion becomes increasingly serious with increasing Ti content. The honeycomb corrossion structure can be clearly observed when the Ti content reaches up to 0.5 at%. The corresponding mechanisms are also discussed in detail.
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