Horizontal transfer and functional evaluation of high pathogenicity islands in Avian Escherichia coli

High pathogenicity islands (HPIs) inEscherichia coliencode genes that are primarily involved in iron uptake and regulation, and confer virulence and pathogenicity. The aim of this study was to investigate the transfer ofHPIs in avianE. coliand identify the function ofHPIin the acceptor strain. TheHPItransfer strain was obtained under conditions of low temperature and low iron abundance, and the donor and acceptor strains were confirmed.E. coli HPIs are transferred by horizontal gene transfer events, which are likely mediated primarily by homologous recombination inHPI-adjacent sequences. Assays for biological activity and pathogenicity changes in the acceptor strain indicated thatHPIs might not be involved in pathogenesis in avianE. coli, and thus the main function ofHPIs in this strain of bacteria may be to regulate iron nutrition.

A simple approach for the discrimination of surfactants based on the control of squaraine aggregation

The color of squaraine solution shows a "fingerprint" change upon addition of different surfactants. A cross-responsive sensing array based on a small molecular probe was applied to discriminate surfactants with 100% confidence limits. Furthermore, the probe can selectively detect sodium dodecyl sulfate (SDS) with turn-on fluorescence response.

[Hepatitis B virus X protein-regulated expression of Plk1]

OBJECTIVE

To investigate the ability and underlying mechanism of hepatitis B virus X protein (HBx) regulation of Polo-like kinase 1 (Plk1) expression.

METHODS

The human HCC cell line HepG2 was transfected (transiently and stably) with an HBx plasmid expression vector (pCMV-HA-HBx) or empty plasmid vector (control), with and without expression plasmids with the Plk1 promoter. Effects on Plk1 expression were assessed by western blotting. Functional effects on the Plk1 promoter were assessed by luciferase reporter assay. Effects on the mRNA level of Plk1 in S phase HepG2 cells were assessed by quantitative real-time reverse transcriptase polymerase chain reaction. After blocking protein synthesis by treatment with cycloheximide (CHX), the turnover rate of Plk1 was assessed by western blotting. Lastly, the effect of HBx on cell cycle was assessed by flow cytometry.

RESULTS

HBx did not increase the protein expression of Plk1 in non-synchronized HepG2 cells, but did significantly up-regulate the Plk1 protein level in the synchronized S phase cells (P = 0.026 and P = 0.003, respectively). Ectopic expression of HBx did not increase the mRNA level of Plk1 in HepG2 cells, but did inhibit the degradation of Plk1, as evidenced by an increased half-life of Plk1 protein (from 30 to 90 minutes). The HBx-expressing HepG2 cells showed more frequent entry into the S or G(2)/M phase than the control cells (31.65% vs. 24.56% or 9.43% vs. 4.47%, respectively) and less in the G(0)/G(1) phase (decrease from 70.97% to 58.92% for the HBx-expressing HepG2 cells).

CONCLUSION

HBx is able to up-regulate the expression of Plk1 in HepG2 cells by a mechanism involving stabilization of the Plk1 protein primarily in the S phase of the cell cycl.

A novel self-assembled platform for the ratiometric fluorescence detection of spermine

A novel self-assembled platform where the micelles of a pyrene derivative act as the shell and squaraine (SQ) as the nucleus was constructed for the ratiometric near infrared (NIR) fluorescence detection of urinary spermine with high selectivity.

CT45A1 acts as a new proto-oncogene to trigger tumorigenesis and cancer metastasis

Cancer/testis antigen (CTA)-45 family (CT45) belongs to a new family of genes in phylogenetics and is absent in normal tissues except for testis, but is aberrantly overexpressed in various cancer types. Whether CT45 and other CTAs act as proto-oncogenes has not been determined. Using breast cancer as a model, we found that CT45A1, a representative CT45 family member, alone had a weak tumorigenic effect. However, its neoplastic potency was greatly enhanced in the presence of growth factors. Overexpression of CT45A1 in breast cancer cells markedly upregulated various oncogenic and metastatic genes, constitutively activated ERK and CREB signaling pathways, promoted epithelial-mesenchymal transition, and increased cell stemness, tumorigenesis, invasion, and metastasis, whereas silencing CT45A1 significantly reduced cancer cell migration and invasion. We propose that CT45A1 functions as a novel proto-oncogene to trigger oncogenesis and metastasis. CT45A1 and other CT45 members are therefore excellent targets for anticancer drug discovery and targeted tumor therapy, and valuable genes in the study of a molecular phylogenetic tree.

Nonlinear eddy viscosity modeling and experimental study of jet spreading rates

Indoor airflow pattern is strongly influenced by turbulent shear and turbulent normal stresses that are responsible for entrainment effects and turbulence-driven secondary motion. Therefore, an accurate prediction of room airflows requires reliable modeling of these turbulent quantities. The most widely used turbulence models include RANS-based models that provide quick solutions but are known to fail in turbulent free shear and wall-affected flows. In order to cope with this deficiency, this study presents a nonlinear k-ε turbulence model and evaluates it along with linear k-ε models for an indoor isothermal linear diffuser jet flow measured in two model rooms using PIV. The results show that the flow contains a free jet near the inlet region and a wall-affected region downstream where the jet is pushed toward the ceiling by entrainment through the well-known Coanda effect. The CFD results show that an accurate prediction of the entrainment process is very important and that the nonlinear eddy viscosity model is able to predict the turbulence-driven secondary motions. Furthermore, turbulence models that are calibrated for high Reynolds free shear layer flows were not able to reproduce the measured velocity distributions, and it is suggested that the model constants of turbulence models should be adjusted before they are used for room airflow simulations.

Trends of hypertension prevalence, awareness, treatment and control in rural areas of northern China during 1991-2011

This study aims to investigate the trends in prevalence, awareness, treatment and control of hypertension among rural residents aged 35-74 years in northern China during the country's rapid economic development from 1991 to 2011. Two surveys, conducted in 1991 and 2011, included 2196 and 1939 participants aged 35-74 years from same villages in Ji County, Tianjin of China, respectively. The prevalence of hypertension, adjusted by age and gender using the world standard population in 2000, increased 30% (39.9% vs 51.7%) between 1991 and 2011. The increase was greatest (68%) in women aged 35-44 years. Meanwhile, the prevalence of stage II hypertension increased by 75% overall, with a 4-fold increase in men aged 45-54 years. Although the awareness, treatment and control of hypertension increased significantly during the same period, they remained unacceptably poor. In conclusion, the community-based surveys showed that the prevalence of hypertension in rural residents of northern China aged 35-74 years increased rapidly over the past 20 years, and most dramatically in young women. Efforts in the primary prevention of hypertension, particularly for young women, and promoting education for hypertension awareness, treatment and control are of paramount importance in rural China.

Abstract 3220: A microfluidic, multi-analyte, high sensitivity, immunoassay platform for rapid biomarker detection

Traditionally, protein analytes or biomarkers have been measured individually in ELISAs. However, it is becoming increasingly clear that multiple markers are associated with multivariate diseases like cancer. Despite demand, the adoption of multi-analyte biomarker tests in clinical research has been severely limited for many reasons including technical concerns regarding assay reproducibility, time and the labor-intensive nature of assay panel development, and reported non-correlation with conventional ELISA data. To address this issue, we have developed a novel fully automated desktop immunoassay platform that enables simultaneous interrogation of four analytes in eight individual samples on a single disposable microfluidic cartridge in under an hour. We have devised a unique approach to immobilize antibodies that results in assays with high sensitivities (femtomolar) and broad dynamic ranges (>4 logs). Twenty microliters of patient sample are split into parallel channels containing individual immunoassays. By segregating each assay to a discrete location, the multi-analyte assay mimics single-analyte ELISAs, thus enabling each assay to operate under its optimal conditions. This methodology combines the specificity of a traditional ELISA immunoassay, where the sample is assayed by a singular pair of capture and detect antibodies eliminating cross-reactivity and other negative interactions from other antibody pairs while offering the benefits of a multiplexed antigen analysis. We describe the system's design, speed, sensitivity and reproducibility using data generated with a custom-built 4-analyte pro-inflammatory panel cartridge (IL-1β, IL-6, IL-10 and TNFα) on clinical samples. We demonstrate that our assay system is ideal for quantitative analysis of soluble protein markers in clinical research and in clinical trials.

Citation Format: Rajiv Pande, John H. Leamon, Marty Putnam, M Pitta, D Svancara, J Tu. A microfluidic, multi-analyte, high sensitivity, immunoassay platform for rapid biomarker detection. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3220. doi:10.1158/1538-7445.AM2013-3220

Tissue distribution, expression, and antimicrobial activity of Anas platyrhynchos avian β-defensin 6

In this study, a novel avian β-defensin (AvBD) was isolated from the Chaohu duck. The complete nucleotide sequence of the gene contained a 204-bp open reading frame that encoded 67 amino acids (aa), including a signal peptide of 20 aa, a propiece of 5 aa, and a mature peptide of 42 aa. The homology, characterization, and comparison of this gene with AvBD from other avian species confirmed that it was duck AvBD6. Also, the preproprotein of AvBD6 from chicken, goose, and duck was highly conserved with 100% aa homology. The AvBD6 mRNA was widely expressed in the investigated tissues of healthy 5-mo-old ducks, with the exception of the skin, kidney, and bursa. The AvBD6 mRNA was highly expressed in the spleen, lung, stomach, tongue, and egg yolk, successively; moderately expressed in the bone marrow and liver; and expressed to lower degrees in the trachea, heart, intestine, muscle, esophagus, and testis. We produced recombinant AvBD6 by expressing the gene in Escherichia coli. The yield of soluble glutathione S-transferees (GST)-AvBD6 in the inclusion bodies increased significantly as the incubation temperature was decreased from 37 to 30°C. As expected, the GST-AvBD6 exhibited strong bactericidal properties [minimum inhibitory concentration (MIC) = 0.5 to 2 μM] against the Aeromonas veronii biovar sobria strain BJCP-5, E. coli, and Enterococcus faecalis [ATCC 29212); it possessed medium bactericidal properties (MIC = 4 to 8 μM) against Staphylococcus aureus, Salmonella enteritidis, Pseudomonas aeruginosa (ATCC 27853), and Bacillus subtilis (CMCC 63501;; and it possessed low bactericidal properties (MIC = 16 μM) against Candida albicans (ATCC 10231). Additionally, the antimicrobial activity of GST-AvBD6 proved to be the same as that of synthetic AvBD6. The A. veronii biovar sobria strain BJCP-5 cells that were treated with GST-AvBD6 showed lysis and shrinkage under scanning electron microscopy. The mechanisms of AvBD6-mediated killing of A. veronii biovar sobria involved both cell lysis and nonlysis. Our results indicate that AvBD6 plays an important role in the innate immunity of the Chaohu duck.

Tunneling-nanotube direction determination in neurons and astrocytes

A tunneling nanotube (TNT) is a newly discovered structure involved in cell-cell communication and is found in various types of cells. Here we identify S100A4 as an extracellular molecule and describe its role in attracting the growth direction of TNTs. Together with its putative receptor, receptor for advanced glycation end product, we demonstrate their involvement in TNT direction guidance. Our results further suggest a mechanism for direction guidance of TNTs. In TNT-initiating cells, p53 activates caspase-3, which leads to S100A4 cleavage and its subsequent decrease in cellular concentration. The decrease in cellular S100A4 induces the formation of a gradient of S100A4, from a low concentration in initiating cells toward a high concentration in target cells. This concentration gradient of S100A4 induces direction guidance for TNTs.

QTL and epistatic analyses of heterosis for seed yield and three yield component traits using molecular markers in rapeseed (Brassica napus L.)

Aiming to explore the basis of heterosis in rapeseed, QTLs for yield and three yield component traits were mapped and the digenic interactions were detected in an F2 population derived from a cross between two elite rapeseed lines, SI-1300 and Eagle, in this study. Twenty-eight QTLs were detected for the four yield traits, with only two of them detected simultaneously in the Wuhan and Jingmen environments. Additive, partial dominance, dominance, and overdominance effects were all identified for the investigated traits. Dominance (including partial dominance) was shown by 55% of the QTLs, which suggests that dominance is a major genetic basis ofheterosis in rapeseed. At the P < or = 0.01 level with 1000 random permutations, 108 and 104 significant digenic interactions were detected in Wuhan and Jingmen, respectively, for the four yield-related traits using all possible locus pairs of molecular markers. Digenic interactions, including additive by additive, additive by dominance, and dominance by dominance, were frequent and widespread in this population. In most cases (78.3%), the interactions occurred among marker loci for which significant effects were not detected by single-locus analysis. Some QTLs (57.1%) detected by single-locus analysis were involved in epistatic interactions. It was concluded that epistasis, along with dominance (including partial dominance), is responsible for the expression of heterosis in rapeseed.

An acoustic rectifier

The detection of acoustic signals is of relevance for a range of practical applications, for example in medical diagnostics. However, whereas rectification of electric current and other energy forms such as thermal flux has been demonstrated, acoustic rectification has not yet been achieved. Here, on the basis of the earlier theoretical proposal of an 'acoustic diode', we present the first experimental demonstration of a rectified energy flux of acoustic waves. A one-dimensional acoustic rectifier is fabricated by coupling a superlattice with a layer of ultrasound contrast agent microbubble suspension. A significant rectifying effect is observed within two frequency bands at locations that agree well with theoretical predictions. Following optimization of the concentration of the microbubble suspension, rectifying ratios can be as high as ~10(4). This realization of an acoustic rectifier should have substantial practical significance, for example in the focusing of ultrasound in medical applications.