Comparative proteomic analysis of vancomycin-sensitive and vancomycin-intermediate resistant Staphylococcus aureus.

PURPOSE: The extensive use of vancomycin has led to the development of Staphylococcus aureus strains with varying degrees of resistance to vancomycin. The present study aimed to explore the molecular causes of vancomycin resistance by conducting a proteomics analysis of subcellular fractions isolated from vancomycin-intermediate resistant S. aureus (VISA) and vancomycin-sensitive S. aureus (VSSA) strains. METHODS: We conducted proteomics analysis of subcellular fractions isolated from 2 isogenic S. aureus strains: strain 11 (VSSA) and strain 11Y (VISA). We used an integrated quantitative proteomics approach assisted by bioinformatics analysis, and comprehensively investigated the proteome profile. Intensive bioinformatics analysis, including protein annotation, functional classification, functional enrichment, and functional enrichment-based cluster analysis, was used to annotate quantifiable targets. RESULTS: We identified 128 upregulated proteins and 21 downregulated proteins in strain 11Y as compared to strain 11. The largest group of differentially expressed proteins was composed of enzymatic proteins associated with metabolic and catalytic activity, which accounted for 32.1% and 50% of the total proteins, respectively. Some proteins were indispensable parts of the regulatory networks of S. aureus that were altered with vancomycin treatment, and these proteins were related to cell wall metabolism, cell adhesion, proteolysis, and pressure response. CONCLUSION: Our proteomics study revealed regulatory proteins associated with vancomycin resistance in S. aureus. Some of these proteins were involved in the regulation of cell metabolism and function, which provides potential targets for the development of strategies to manage vancomycin resistance in S. aureus.

B24N24 nanocage as an electronic sensor for metronidazole drug: density functional theory studies.

This paper implemented the density functional theory (DFT) to evaluate a nano-structured sensor of the metronidazole (ML) drug based on the interaction between pristine B24N24 nanocage and the drug. Chemisorption (adsorption energy = - 13.77 to - 15.11 kcal/mol) and physisorption (= - 1.48 to - 4.97 kcal/mol) were estimated to be potential mechanisms of adsorption. The substantial rise in the electrical conductivity of B24N24 suggested that the nanocage was capable of generating electronic noise in interaction with the drug. In addition, the adsorption of the drug significantly influenced the work function, Fermi level, and complexes (chemisorption) of the highest stability. This suggests that one can detect ML through the Φ-type nano-sensing efficiency of B24N24. The recovery process takes nearly 0.005 s, and it was observed that bare B24N24 nanocages could be employed without costly manipulations of the structure for sensitivity improvement. The UV-Vis results indicated that ML adsorption upshifted the transmission wavelength at 391.07 nm. Thus, the close distance of the drug molecule from the nanocage led to the redshift. It was concluded that B24N24 nanocages could be an effective and efficient nanosensor for the detection of ML in light of their structural characteristics and electronic properties.

Seven novel variants expand the spectrum of RPE65-related Leber congenital amaurosis in the Chinese population.

Purpose: To screen RPE65 in 187 families with Leber congenital amaurosis (LCA). Methods: Sanger sequencing and/or targeted exome sequencing was employed to identify mutations in the RPE65 gene, and intrafamilial cosegregation analysis if DNA was available. In silico analyses and splicing assay were used to evaluate the variants' pathogenicity. Results: Genetic analysis revealed 15 mutations in RPE65 in 14 pedigrees, including one splice-site mutation, one frameshift mutation, three nonsense mutations, and ten missense mutations. Of the mutations identified in RPE65, seven are novel associated with LCA, including five missense variants (c.124C>T, c.149T>C, c.340A>C, c.425A>G, and c.1399C>G) and two indel (insertions or deletions) variants (c.858+1delG and c.1181_1182insT). In vitro splicing assay was performed to evaluate the functional impact on RNA splicing of novel mutations if two of three in silico analyses were predicated to be non-pathogenic at the protein level. Among these 15 variants, 14 were classified as 'pathogenic variants,' and a variant (c.124C>T) was 'variants with uncertain significance' according to the standards and guidelines of the American College of Medical Genetics and Genomics. Conclusions: Mutations in RPE65 were responsible for 11 of the cohort of 187 Chinese families with LCA, which expands the spectrum of RPE65-related LCA in the Chinese population and potentially facilitates its clinical implementation.

Effect of lncRNA BNC2-AS1 on the Proliferation, Migration and Invasion of Gastric Cancer Cells.

Background: Gastric cancer is one of the most common cancers and is the second leading cause of cancer mortality worldwide. The present study aimed to investigate the potential biological effect of long non-coding RNA (lncRNA) BNC2-AS1 on the proliferation, migration, and invasion of cervical cancer cells. Methods: BNC2-AS1 small interfering RNA (siRNA) was transfected into SGC7901 and BGC823 gastric cancer cell lines, with negative siRNA serving as a control. A reverse transcription-quantitative polymerase chain reaction assay was performed to confirm the knockdown of BNC2-AS1. Cell Counting Kit (CCK)-8 and colony-forming unit (CFU) assays were performed to evaluate the effect of BNC2-AS1-knockdown on SGC7901 and BGC823 cell proliferation. A wound healing assay was performed to evaluate the effect of BNC2-AS1-knockdown on SGC7901 and BGC823 cell proliferation and migration. A tumor invasion assay was used to evaluate the effect of BNC2-AS1-knockdown on SGC7901 and BGC823 cell invasion. The expression level of BNC2-AS1 was efficiently knocked down by siRNA 48 hours post-transfection. Results: The results of CCK8 and CFU assays showed that BNC2-AS1-knockdown significantly decreased gastric cancer cell proliferation. Wound healing assay results indicated that BNC2-AS1-knockdown markedly suppressed gastric cancer cell proliferation and migration. Tumor invasion assay results demonstrated that BNC2-AS1-knockdown significantly suppressed gastric cancer cell invasion. Conclusions: BNC2-AS1 levels in gastric cancer SGC7901 and BGC823 cell lines can be efficiently knocked down using the siRNA strategy, and the BNC2-AS1 knockdown can significantly suppress the tumor characteristics of gastric cancer cells, including the ability of proliferation, migration, and invasion.

Blocking of the EGFR-STAT3 signaling pathway through afatinib treatment inhibited the intrahepatic cholangiocarcinoma.

Epidermal growth factor receptor (EGFR) and downstream signal transducer and activator of transcription 3 (STAT3) signaling have been extensively implicated in various human neoplasms. Recently, a novel EGFR inhibitor, known as afatinib, has exhibited broad antitumor activities in a variety of tumors. Therefore, the present study attempted to investigate the impact of this agent on intrahepatic cholangiocarcinoma (ICC). Initially, immunohistochemical assays were performed on 15 human ICC specimens and their adjacent tissues in order to assess the protein levels of phosphorylated EGFR (pEGFR) and pSTAT3. Subsequently, the human ICC cell lines JCK and OZ were exposed to different doses of afatinib, and then cell viability and apoptosis were determined by MTT assay and flow cytometry, respectively. Furthermore, immunoblotting was applied to detect any variations in the phosphorylated protein levels of EGFR and STAT3 in afatinib-treated ICC cells. The results of the current study demonstrated that ICC specimens had evidently increased pEGFR and pSTAT3 protein levels as compared with the adjacent noncancerous tissues. Further in vitro experiments indicated that afatinib evidently blocked ICC cell growth and induced cell apoptosis. At the protein level, pEGFR and pSTAT3 were evidently attenuated by afatinib-administration. In conclusion, the present study clearly determined that afatinib exerts an antitumor effect on ICC cells by silencing the EGFR-STAT3 signaling pathway. This novel agent deserves further investigation as a potential therapeutic strategy for ICC.

CircRNAs as Potential Biomarkers in Gastrointestinal Tract Tumors: Opportunities and Challenges.

Most digestive system tumors have poor prognoses due to the lack of specific biomarkers. Circular RNAs (circRNAs) regulate the expression of genes and play essential roles in digestive system tumorigenesis. Here we review circRNA functions in gastrointestinal tract tumors. CircRNAs are promising biomarkers for clinical applications for gastrointestinal tract tumors.

Increased Expression of Long Noncoding RNA RP11-62F24.2 in Gastric Cancer and Its Clinical Significance.

BACKGROUND: Long noncoding RNAs (lncRNAs) are transcripts longer than 200 nucleotides and have no proteincoding capacity. In recent years, they have been believed to be major players in biological processes. However, there is limited understanding of the many lncRNAs' expressions and their clinical significances in gastric cancer. METHODS: Quantitative RT-PCR was performed to investigate the lncRNA expression in gastric cancer. Then, we further explored the potential association between RP11-62F24.2 level and the clinicopathological features in gastric cancer tissue samples. RESULTS: The results showed that RP11-62F24.2 was significantly upregulated in gastric cancer tissues compared with matched normal tissues (p < 0.05). Its expression level was significantly correlated with invasion and tumor size. CONCLUSIONS: These results indicated that lncRNA RP11-62F24.2 may be a potential biomarker in the diagnosis of gastric cancer.

Probing dynamic fluorescence properties of single and clustered quantum dots toward quantitative biomedical imaging of cells.

We present results on the dynamic fluorescence properties of bioconjugated nanocrystals or quantum dots (QDs) in different chemical and physical environments. A variety of QD samples was prepared and compared: isolated individual QDs, QD aggregates, and QDs conjugated to other nanoscale materials, such as single-wall carbon nanotubes (SWCNTs) and human erythrocyte plasma membrane proteins. We discuss plausible scenarios to explain the results obtained for the fluorescence characteristics of QDs in these samples, especially for the excitation time-dependent fluorescence emission from clustered QDs. We also qualitatively demonstrate enhanced fluorescence emission signals from clustered QDs and deduce that the band 3 membrane proteins in erythrocytes are clustered. This approach is promising for the development of QD-based quantitative molecular imaging techniques for biomedical studies involving biomolecule clustering.

Multimodal, nanoscale, hyperspectral imaging demonstrated on heterostructures of quantum dots and DNA-wrapped single-wall carbon nanotubes.

A multimodality imaging technique integrating atomic force, polarized Raman, and fluorescence lifetime microscopies, together with 2D autocorrelation image analysis is applied to the study of a mesoscopic heterostructure of nanoscale materials. This approach enables simultaneous measurement of fluorescence emission and Raman shifts from a quantum dot (QD)-single-wall carbon nanotube (SWCNT) complex. Nanoscale physical and optoelectronic characteristics are observed including local QD concentrations, orientation-dependent polarization anisotropy of the SWCNT Raman intensities, and charge transfer from photoexcited QDs to covalently conjugated SWCNTs. Our measurement approach bridges the properties observed in bulk and single nanotube studies. This methodology provides fundamental understanding of the charge and energy transfer between nanoscale materials in an assembly.

[Stress analysis of the staggered and straight placement of implants in the mandibular posterior region under the localized load].

OBJECTIVE: To compare the stress distribution of the staggered and straight placement of implants in the mandibular posterior region. METHODS: Using three-dimensional finite element approach to analyze the stress distribution and variance regularity under the localized load. RESULTS: Under vertical load, the stress peak value reduced when wide implant was placed straight (min: 3.70 MPa), but slightly increased when normal implant was placed staggered (max: 8.32 MPa); under the inclined load from buccal to lingual direction, the stress peak value reduced when the wide implant was placed in straight line (min: 12.29 MPa) or normal implant was placed staggered with buccal offset configuration (min: 15.48 MPa), but increased with lingual offset configuration (max: 23.60 MPa). CONCLUSIONS: Wide implant (> or = 4 mm) with straight placement should be adopted to reduce the stress peak value and improve stress distribution, when the buccolingual diameter of the alveolar ridge in the mandibular posterior region was wide.

[A three-dimensional finite element study on composite archwire applied in extraction cases].

OBJECTIVE: To explore mechanical properties of the composite archwire (CoAW) applied in extraction cases. METHODS: The mandibular three dimensional model was established by spiral computed tomography scanning and SOLIDWORKS 2001 PLUS software. The archwire model was established by means of ANSYS software. The mechanical analysis and calculation of CoAW were carried out. RESULTS: With the diameter of NiTi part of CoAW gradually augmented (the diameter of stainless steel part kept unchanged), the stress on teeth gradually increased. As the diameter of stainless steel part of CoAW gradually augmented (the diameter of NiTi part kept unchanged), the stress on teeth also gradually increased. The CoAW (0.30 mm NiTi round wire combined with 0.36 mm stainless steel round wire) produced the least force on teeth. There was little contradistinction between six kinds of CoAW and stainless steel wire on the stress of posterior teeth. CONCLUSIONS: The stress on teeth closely correlated with the diameter of the composite archwire.

Temperature dependence of the Raman spectra of individual carbon nanotubes.

Resonant Raman scattering (RRS) spectra of individual carbon nanotubes on a SiO2 substrate have been investigated first in the temperature range of 100-600 K (Phys. Rev. B 2002, 66, 115411). It was revealed by the intensity abnormality of the radial breathing mode (RBM) that the carbon nanotubes have a temperature-dependent density of electronic states. This means that the previously reported temperature coefficients of RBM of carbon nanotubes are smaller than their "real" ones for the bulk samples of single- or double-walled carbon nanotubes. Comparatively, the G line of individual nanotubes shows no observable difference relative to the bulk samples.