Detection of mycobacterial small RNA in the bacterial culture supernatant and plasma of patients with active tuberculosis.

Bacterial small RNA (sRNA) has been shown to play an important role in control of bacteria virulence, stress response and physiological metabolism by post-transcriptional regulation of gene expression. However, there were few reports about bacterial sRNA as a biomarker of infection. To test the potential role of sRNA in indicating infection of Mycobacterium tuberculosis, total RNA were extracted from the filtrated bacterial cultural supernatant. After synthesis of cDNA by reverse transcription, four Mycobacterial sRNAs including ASdes, ASpks, AS1726, and AS1890, which have been experimentally confirmed by Kristine B in the year of 2009, were detected by real time PCR. The specificity was verified by sequencing of the amplified products. Moreover, we demonstrate that the presence of sRNA Asdes in plasma of 55.56% (15/27) TB patients and 25.00% (6/24) normal controls with BCG vaccination (P < 0.05). Our results suggest that bacterial non-coding sRNA can be detected from either bacterial culture supernatants or patient's plasma. Detecting of Mycobacterial sRNA provides a rapid and relatively noninvasive approach for diagnosing disease and could be developed as a biomarker to identify patients with active tuberculosis to help make informed decisions about proper therapies.1.

Vitronectin [correction of Vitronetcin] promotes cell growth and inhibits apoptotic stimuli in a human hepatoma cell line via the activation of caspases.

This study sought to understand the effects of vitronectin (VTN) on the growth of SMMC-7721 hepatoma cells. In addition, this study examined how VTN inhibits the induction of apoptosis in SMMC-7721 cells by 3,3'-diindolylmethane (DIM), a metabolite of natural phytochemicals, and preliminarily investigated the signaling molecules involved in this process. A cell proliferation reagent was used to observe the effects of VTN on cell proliferation rates. Laser scanning confocal microscopy was performed to observe the effects of VTN on the morphology of tubulin, a component of the cytoskeleton. Flow cytometry and Western blotting assays were used to observe the inhibitory effects of VTN on DIM-induced apoptosis in SMMC-7721 cells and changes in the expression levels of the signaling molecules involved in this process. VTN promoted tumor cell growth in a concentration-dependent manner and inhibited apoptosis caused by the effects of apoptosis-inducing agents. Under in vitro experimental conditions, VTN contributed to the growth of SMMC-7721 hepatoma cells and protected them from the effects of an apoptosis-inducing agent. These findings suggest that during hepatocellular carcinogenesis, VTN may promote tumor cell growth and inhibit chemically induced apoptosis.

Novel Airflow-Field-Driven Melt Spinning 3D Printing of Tubular Scaffolds Based on Polycaprolactone Blends.

The fabrication of various 3D tissue engineering tubular scaffolds with fibrous structures, to assist the human body in rapidly repairing a variety of ailments, is receiving more and more attention. Due to the inefficiency of the majority of fibrous preparation techniques, the question of how to rapidly produce the requisite three-dimensional tubular microfiber scaffold structures has become an urgent problem. In this study, an efficient polymer fiber preparation method was developed, using a high-speed airflow drive. Melt blending of polycaprolactone (PCL), polylactic acid (PLA), and tributyl citrate (TBC), was used for the printing material, to achieve the efficient preparation of tubular microfiber scaffolds with different structures. The scaffold diameter was as small as 2 mm, the wall thickness was up to 100 µm, and the fiber injection efficiency reached 15.48 g/h. By utilizing simulations to optimize the printing parameters and by adjusting the printing settings, it was possible to achieve a controlled fiber diameter in the range of 3 µm to 15 µm. In addition, plasma treatment was applied to the microfibers' surface, to increase their wettability, and the efficiency of the hydrophilic modification was demonstrated. Furthermore, the mechanical property test demonstrated that the fibers have a tensile strength of 1.36 ± 0.16 MPa and a tensile strain of 30.8 ± 3.5%. The radial compressive strain of the tubular scaffold could reach 60% of the original scaffold's diameter. Finally, the in vitro degradation of the fibers at various pH values was tested. The results showed that, under alkaline conditions, the surface of the fibers would be severely crushed and the rate of deterioration would increase.

Siderophore iucA of hypermucoviscous Klebsiella pneumoniae promotes liver damage in mice by inducing oxidative stress.

The hypermucoviscosity/hypervirulent K. pneumoniae (hvKP) is a dominant cause of pyogenic liver abscess (PLA) and has contributed to the endemicity of disease in Asian country. The siderophore aerobactin (iucA) is highly expressed in hvKP and acting virulence role during hvKP infection. However, its role in the PLA is poorly understood. We constructed iucA deletion mutant (ΔiucA-hvKP852) and used animal study to characterize the role of siderophore iucA in K. pneumoniae liver abscess. The animal experiments showed that ΔiucA-hvKP852 strain had lower virulence in mice compared to hvKP852 wild type strain. At 24 h after infection, only two of ten mice developed liver abscess during infection with ΔiucA-hvKP852 strain, while nine of ten mice infected with wild type hvKP852 strain showed multiple lesions of liver abscess. The liver tissue infected with ΔiucA-hvKP852 exhibited low reactive oxygen stress levels compared to those infected by wild type hvKP852 strain (P < 0.05). The results suggest that siderophore iucA play an important role in the liver abscess by inducing oxidative stress.

Multi-Scale Structure and Directional Hydrophobicity of Titanium Alloy Surface Using Electrical Discharge.

Titanium alloys with special macro-micro composite structures of directional hydrophobicity are difficult to prepare due to poor thermal conductivity and good corrosion resistance, inhibiting the wide engineering applications for aerospace, marine engineering, and biomedicine. To prepare macro-micro composite structures on the surface of titanium alloys and achieve directional hydrophobicity, the sub-millimeter structures with an edge width of 150 µm, a groove width of 250 µm, and a depth of 250 µm were fabricated on the titanium alloy by wire electrical discharge machining (WEDM) technology, and high voltage-induced weak electric arc machining (HV-µEAM) was used to fabricate micro-scale feature size micro-structures on the processed macro-structure edges. The influence of process parameters on the morphology of microstructures was studied experimentally. The smooth surface of the titanium alloy is isotropically hydrophilic, and its contact angle is 68°. After processing the macrostructure on the titanium alloy surface, it shows directional hydrophobicity after being modified by low surface energy materials. The macro-micro composite structure formed by HV-µEAM realizes a directional hydrophobic surface with contact angles (CA) of 140° (parallel direction) and 130° (perpendicular direction), respectively. This surface has been modified with low surface energy to achieve contact angles of 154° and 143°. The results of the abrasion resistance test show that under the load of 100 g, it retains directional hydrophobicity at a friction distance of 700 mm with 600# sandpaper. The existence of the sub-millimeter macrostructure is the reason for the directionality of surface hydrophobicity. The microstructure can realize the transformation of the titanium alloy surface from hydrophilic to hydrophobic. Under the combined effects of the macro and micro composite structure, the surface of the titanium alloy shows obvious directional hydrophobicity.

Indirect ELISA with recombinant GP5 for detecting antibodies to porcine reproductive and respiratory syndrome virus.

Porcine reproductive and respiratory syndrome is caused by the PRRS virus (PRRSV), which has six structural proteins (GP2, GP3, GP4, GP5, M and N). GP5 and N protein are important targets for serological detection by enzyme-linked immunosorbent assay (ELISA) and other methods. Toward this goal, we developed an indirect ELISA with recombinant GP5 antigens and this method was validated by comparison to the LSI PRRSV-Ab ELISA kit. The results indicated that the optimal concentration of coated recombinant antigen was 0.2 µg/well for a serum dilution of 1:40. The rate of agreement with the LSI PRRSV-Ab kit was 88.7% (266/300). These results support the potential use of recombinant GP5 as an antigen for indirect ELISA to detect PRRSV antibodies in pigs.