Subinhibitory Concentrations of Thymol Reduce Enterotoxins A and B and α-Hemolysin Production in Staphylococcus aureus Isolates

BACKGROUND: Targeting bacterial virulence factors is now gaining interest as an alternative strategy to develop new types of anti-infective agents. It has been shown that thymol, when used at low concentrations, can inhibit the TSST-1 secretion in Staphylococcus aureus. However, there are no data on the effect of thymol on the production of other exotoxins (e.g., alpha-hemolysin and enterotoxins) by S. aureus. METHODOLOGY/PRINCIPAL FINDINGS: Secretion of alpha-hemolysin, SEA and SEB in both methicillin-sensitive and methicillin-resistant S. aureus isolates cultured with graded subinhibitory concentrations of thymol was detected by immunoblot analysis. Hemolysin and tumor necrosis factor (TNF) release assays were performed to elucidate the biological relevance of changes in alpha-hemolysin, SEA and SEB secretion induced by thymol. In addition, the influence of thymol on the transcription of hla, sea, and seb (the genes encoding alpha-hemolysin, SEA and SEB, respectively) was analyzed by quantitative RT-PCR. Thymol inhibited transcription of hla, sea and seb in S. aureus, resulting in a reduction of alpha-hemolysin, SEA and SEB secretion and, thus, a reduction in hemolytic and TNF-inducing activities. CONCLUSIONS/SIGNIFICANCE: Subinhibitory concentrations of thymol decreased the production of alpha-hemolysin, SEA and SEB in both MSSA and MRSA in a dose-dependent manner. These data suggest that thymol may be useful for the treatment of S. aureus infections when used in combination with beta-lactams and glycopeptide antibiotics, which induce expression of alpha-hemolysin and enterotoxins at subinhibitory concentrations. Furthermore, the structure of thymol may potentially be used as a basic structure for development of drugs aimed against these bacterial virulence factors

Evaluating the role of serum uric acid in the risk stratification and therapeutic response of patients with pulmonary arterial hypertension associated with congenital heart disease (PAH-CHD)

Background: Pulmonary arterial hypertension (PAH) is a malignant pulmonary vascular disease that negatively impacts quality of life, exercise capacity, and mortality. This study sought to investigate the relationship between serum uric acid (UA) level and the disease severity and treatment response of patients with PAH and congenital heart disease (PAH-CHD).Methods: This study included 225 CHD patients and 40 healthy subjects. Serum UA was measured in all patients, and UA levels and haemodynamic parameters were re-evaluated in 20 patients who had received PAH-specific drug treatment for at least 7 ± 1 month.Results: Serum UA levels were significantly higher in PAH-CHD patients than in CHD patients with a normal pulmonary artery pressure and normal subjects (347.7 ± 105.7 μmol/L vs. 278.3 ± 84.6 μmol/L; 347.7 ± 105.7 μmol/L vs. 255.7 ± 44.5 μmol/L, p < 0.05). UA levels in the intermediate and high risk groups were significantly higher than those in the low-risk group (365.6 ± 107.8 μmol/L vs. 311.2 ± 82.8 μmol/L; 451.6 ± 117.6 μmol/L vs. 311.2 ± 82.8 μmol/L, p < 0.05). Serum UA levels positively correlated with mean pulmonary arterial pressure, WHO functional class, pulmonary vascular resistance, and NT-proBNP (r = 0.343, 0.357, 0.406, 0.398; p < 0.001), and negatively with mixed venous oxygen saturation (SvO2) and arterial oxygen saturation (SaO2) (r = −0.293, −0.329; p < 0.001). UA significantly decreased from 352.7 ± 97.5 to 294.4 ± 56.8 μmol/L (p = 0.001) after PAH-specific drug treatment for at least 6 months, along with significant decreases in mean pulmonary arterial pressure and pulmonary vascular resistance and increases in cardiac index and mixed SvO2.Conclusion: Serum UA can be used as a practical and economic biomarker for risk stratification and the evaluation of PAH-specific drug treatment effects for patients with PAH-CHD

Differential expression spectrum and targeted gene prediction of tRNA-derived small RNAs in idiopathic pulmonary arterial hypertension

Background: Idiopathic pulmonary arterial hypertension (PAH) is a potentially fatal pulmonary vascular disease with an extremely poor natural course. The limitations of current treatment and the unclear etiology and pathogenesis of idiopathic PAH require new targets and avenues of exploration involved in the pathogenesis of PAH. tRNA-derived small RNAs (tsRNAs), a new type of small non-coding RNAs, have a significant part in the progress of diverse diseases. However, the potential functions behind tsRNAs in idiopathic PAH remain unknown.Methods: Small RNA microarray was implemented on three pairs of plasma of idiopathic PAH patients and healthy controls to investigate and compare tsRNAs expression profiles. Validation samples were used for real-time polymerase chain reaction (Real-time PCR) to verify several dysregulated tsRNAs. Bioinformatic analysis was adopted to determine potential target genes and mechanisms of the validated tsRNAs in PAH.Results: Microarray detected 816 statistically significantly dysregulated tsRNAs, of which 243 tsRNAs were upregulated and 573 were downregulated in PAH. Eight validated tsRNAs in the results of Real-time PCR were concordant with the small RNA microarray: four upregulated (tRF3a-AspGTC-9, 5’tiRNA-31-GluCTC-16, i-tRF-31:54-Val-CAC-1 and tRF3b-TyrGTA-4) and four downregulated (5’tiRNA-33-LysTTT-4, i-tRF-8:32-Val-AAC-2, i-tRF-2:30-His-GTG-1, and i-tRF-15:31-Lys-CTT-1). The Gene Ontology analysis has shown that the verified tsRNAs are related to cellular macromolecule metabolic process, regulation of cellular process, and regulation of cellular metabolic process. It is disclosed that potential target genes of verified tsRNAs are widely involved in PAH pathways by Kyoto Encyclopedia of Genes and Genomes.Conclusion: This study investigated tsRNA profiles in idiopathic PAH and found that the dysregulated tsRNAs may become a novel type of biomarkers and possible targets for PAH

Volcanic Age and Geochemistry of the Permian Linxi Formation in Northeast China: Implications for the Tectonic Evolution of the Paleo-Asian Ocean

The tectonic evolution of the Paleo-Asian Ocean (PAO) has been well studied, including its gradual narrowing and closure by subduction. However, aspects of the tectonic evolution of the oceanic domain remain unclear, including the exact timing and nature of the closure. The Central Asian Orogenic Belt (CAOB) was formed by the closure of the PAO and, therefore, contains information about the tectonic evolution of the oceanic domain. Here, we report a study of the petrology, geochronology, and geochemistry of the Taohaiyingzi section of the Permian Linxi Formation in Alukhorqin Banner (Northeast China) in the central part of the CAOB. A newly discovered andesitic tuff from the lower part of the Linxi Formation yields a weighted mean 206Pb/238U age of 262.2 ± 1.1 Ma (n = 87), indicating that the lower part of the Linxi Formation of the Taohaiyingzi section was deposited during the late Guadalupian. Provenance weathering indicators show that the sedimentary rocks of the Linxi Formation are of low maturity. Element geochemical characteristics indicate that the Linxi Formation clastic rocks were derived from eroded magmatic rocks that formed in a continental arc setting and were deposited close to the arc in a continental arc basin environment. The active margin setting was generated by the subduction of the paleo-Asian oceanic plate beneath the Xilinhot–Songliao block. The inferred palaeosalinity of the sedimentary environment changed gradually from brackish to fresh water, suggesting the end of oceanic plate subduction during the late Guadalupian, and the closure of the PAO during or after the Lopingian

Subinhibitory Concentrations of Perilla Oil Affect the Expression of Secreted Virulence Factor Genes in Staphylococcus aureus

BACKGROUND: The pathogenicity of staphylococcus aureus is dependent largely upon its ability to secrete a number of virulence factors, therefore, anti-virulence strategy to combat S. aureus-mediated infections is now gaining great interest. It is widely recognized that some plant essential oils could affect the production of staphylococcal exotoxins when used at subinhibitory concentrations. Perilla [Perilla frutescens (L.) Britton], a natural medicine found in eastern Asia, is primarily used as both a medicinal and culinary herb. Its essential oil (perilla oil) has been previously demonstrated to be active against S. aureus. However, there are no data on the influence of perilla oil on the production of S. aureus exotoxins. METHODOLOGY/PRINCIPAL FINDINGS: A broth microdilution method was used to determine the minimum inhibitory concentrations (MICs) of perilla oil against S. aureus strains. Hemolysis, tumour necrosis factor (TNF) release, Western blot, and real-time RT-PCR assays were performed to evaluate the effects of subinhibitory concentrations of perilla oil on exotoxins production in S. aureus. The data presented here show that perilla oil dose-dependently decreased the production of α-toxin, enterotoxins A and B (the major staphylococcal enterotoxins), and toxic shock syndrome toxin 1 (TSST-1) in both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA). CONCLUSIONS/SIGNIFICANCE: The production of α-toxin, SEA, SEB, and TSST-1 in S. aureus was decreased by perilla oil. These data suggest that perilla oil may be useful for the treatment of S. aureus infections when used in combination with β-lactam antibiotics, which can increase exotoxins production by S. aureus at subinhibitory concentrations. Furthermore, perilla oil could be rationally applied in food systems as a novel food preservative both to inhibit the growth of S. aureus and to repress the production of exotoxins, particularly staphylococcal enterotoxins

A novel DSPP mutation causes dentinogenesis imperfecta type II in a large Mongolian family

<p>Abstract</p> <p>Background</p> <p>Several studies have shown that the clinical phenotypes of dentinogenesis imperfecta type II (DGI-II) may be caused by mutations in <it>dentin sialophosphoprotein </it>(<it>DSPP</it>). However, no previous studies have documented the clinical phenotype and genetic basis of DGI-II in a Mongolian family from China.</p> <p>Methods</p> <p>We identified a large five-generation Mongolian family from China with DGI-II, comprising 64 living family members of whom 22 were affected. Linkage analysis of five polymorphic markers flanking <it>DSPP </it>gene was used to genotype the families and to construct the haplotypes of these families. All five DSPP exons including the intron-exon boundaries were PCR-amplified and sequenced in 48 members of this large family.</p> <p>Results</p> <p>All affected individuals showed discoloration and severe attrition of their teeth, with obliterated pulp chambers and without progressive high frequency hearing loss or skeletal abnormalities. No recombination was found at five polymorphic markers flanking DSPP in the family. Direct DNA sequencing identified a novel A→G transition mutation adjacent to the donor splicing site within intron 3 in all affected individuals but not in the unaffected family members and 50 unrelated Mongolian individuals.</p> <p>Conclusion</p> <p>This study identified a novel mutation (IVS3+3A→G) in <it>DSPP</it>, which caused DGI-II in a large Mongolian family. This expands the spectrum of mutations leading to DGI-II.</p

SIMULATION AND ANALYSIS ON THERMAL CHARACTERISTIC OF SPINDLE REDUCER BOX OF BORING AND MILLING MACHINING CENTER

The 3D model of spindle reducer box of Boring and Milling Machining Center was established. The gear transmission was analyzed. The thermal load was found by calculating the heat flow of the gear and the heat generated of bearing.The calculated heat convection coefficient was defined as the boundary condition. The temperature field of the spindle reducer box was simulated. By thermal-structure coupling analysis,the thermal deformation results of the box and gears were obtained.Finally,the reliability of spindle box was verified according to the comparison of the simulation result against the nominal clearance

Q and Zheng H: Migration of retinal pigment epithelium cells is regulated by protein kinase Calpha in vitro. Invest Ophthalmol Vis Sci 54

PURPOSE. Retinal pigment epithelium (RPE) cell migration and proliferation are considered key elements in proliferative vitreoretinopathy (PVR). Downregulation of protein kinase Ca (PKCa) can inhibit RPE cell proliferation. Here, we sought to analyze whether PKCa affects the migration of RPE cells. METHODS. Human RPE (hRPE) cells were cultured, confirmed by immunofluorescence staining, and divided into four groups: control, thymeleatoxin, non-small interfering RNA (siRNA), and siRNA-PKCa. Thymeleatoxin was used to activate PKCa, and siRNA-PKCa was used to knock it down. Expression of PKCa was confirmed by quantitative RT-PCR (qRT-PCR). Cell migration ability was analyzed by wound healing assay and transwell chamber assay. Expression of zonula occludens (ZO)-1 and occludin was determined by immunofluorescence. RESULTS. Pure populations of hRPE cell cultures were observed using light and fluorescence microscopy. The mRNA levels of PKCa were not significantly increased by thymeleatoxin, but were reduced by siRNA-PKCa as determined by qRT-PCR assay. The wound healed faster in the thymeleatoxin group than in the control group at time points 12, 15, and 20 hours. The wound healed more slowly in the siRNA-PKCa group than in the non-siRNA group at the three time points. A similar tendency among the four groups was consistently observed in regard to cell numbers counted in the transwell chamber assay. The expression of ZO-1 was highest in the siRNA-PKCa group, similar in the control and non-siRNA groups, and lowest in the thymeleatoxin group. After migration, the fluorescence intensity of ZO-1 was reduced to similarly weak levels among the four groups. CONCLUSIONS. Retinal pigment epithelium cell migration is enhanced by a PKCa agonist and suppressed by a PKCa antagonist. The results suggest that a PKCa-mediated signal transduction pathway plays a crucial role in hRPE cell migration and may be a potential therapeutic target against hRPE cell migration and PVR disease

Petroleum systems and resource potential in Sverdrup Basin, Arctic

The Sverdrup Basin is one of the important petroliferous basins in the Arctic. It has abundant oil and gas resources, but the exploration degree is relatively low. Based on the IHS database and literatures in the public domain, this paper documented the geological characteristics and distribution of oil and gas in the Sverdrup Basin, and classified the petroleum systems and hydrocarbon plays in the basin. The undiscovered hydrocarbons were eventually assessed by Monte Carlo simulation and the favorable exploration areas were predicted. The investigation results show that the discovered oil and gas accumulations are mainly distributed in the western area of the basin, which consists of Sabin and Edinburgh sub-basins. Oil and gas are mainly reserved in the Jurassic and Triassic clastic reservoirs. Two petroleum systems, which are the Paleozoic and Mesozoic systems, were identified in the basin. The Mesozoic petroleum system has a far greater exploration potential. Undiscovered recoverable reserves (mean value) in the Mesozoic petroleum system are 474.81 MMbbl (1 MMbbl=1×106 bbl, 1 bbl=0.137 t) of oil, 13 620.82 Bcf (1 Bcf=1×109 ft3, 1 ft3=0.028 3 m3) of natural gas and 63.66 MMbbl of condensate, amounting to 2 808.61 MMboe (3.85×108 t), of which the natural gas accounts for 80.82%. The Lower Jurassic structural hydrocarbon play in the western area of the basin, the Upper Triassic-Lower Jurassic structural hydrocarbon play in the Edinburgh sub-basin and the Upper Jurassic structural hydrocarbon play in the Sabine sub-basin are the most promising exploration areas

Elevated levels of von Willebrand factor and high mobility group box 1 (HMGB1) are associated with disease severity and clinical outcome of scrub typhus

Objectives: This study aimed to investigate whether von Willebrand factor (vWF) and high mobility group box 1 (HMGB1) are associated with the severity and clinical outcome of scrub typhus and to seek novel biomarkers for surveillance and prediction of the prognosis of this infection. Methods: Serum concentrations of vWF and HMGB1 were measured twice by ELISA for scrub typhus patients (n = 103), once prior to doxycycline therapy and then on day 7 of doxycycline therapy; concentrations were measured once for healthy controls (n = 32). Results: Among the total 103 patients enrolled, 38 had disease complicated by multiple organ dysfunction syndrome (MODS). Serum concentrations of vWF and HMGB1 were significantly higher in all the patients than in the healthy controls, both prior to doxycycline treatment and on day 7 of doxycycline treatment (p < 0.01). Furthermore, serum levels of vWF, HMGB1, and creatinine (SCr) in the patients with MODS increased distinctly, while the platelet (PLT) count diminished markedly compared to the levels in patients without MODS (p < 0.01). The concentration of vWF was positively correlated with that of HMGB1 (r = 0.764, p < 0.001) and SCr (r = 0.528, p < 0.001), but negatively correlated with the PLT count (r = −0.632, p < 0.001). Both HMGB1 and vWF were significantly associated with mortality in scrub typhus (area under the curve (AUC) = 0.864, p = 0.001, and AUC = 0.862, p = 0.001, respectively). Conclusions: Elevated levels of vWF and HMGB1 are associated with the severity and clinical outcome of scrub typhus. These represent possible new biomarkers for use in the assessment and prognostic prediction of this infection