A facile hydrothermal method is utilized to synthesize zinc oxide-reduced graphene oxide nanocomposites for an electrochemical hydrazine sensor.

Background: HVR1 spans 27 residues at the N terminus of the HCV envelope glycoprotein E2 and is the most variable region within the HCV polyprotein. Results: Three independent functional microdomains were identified in HCV HVR1. Conclusion: Different microdomains in HVR1 cooperate to mediate HCV cell entry and immune evasion. Significance: The data provide novel insights into understanding the mechanisms of HCV infection and immune evasion.

Antimicrobial peptides are promising alternatives to traditional antibiotics. A group of selfassembling lipopeptides was formed by attaching an acyl chain to the N-terminus of α-helix forming peptides with the sequence C x -G(IIKK) y I-NH 2 (C x G y , x = 4-12 and y = 2). C x G y selfassemble into nanofibers above their critical aggregation concentrations (CACs). With increasing x, the CACs decrease and the hydrophobic interactions increase, promoting secondary structure transitions within the nanofibers. Antimicrobial activity, determined by the minimum inhibition concentration (MIC), also decreases with increasing x, but the MICs are significantly smaller than the CACs, suggesting effective bacterial membrane disrupting power. Unlike conventional antibiotics, both C 8 G 2 and C 12 G 2 can kill S. aureus and E. coli after only minutes of exposure. C 12 G 2 nanofibers have considerably faster killing dynamics and lower cytotoxicity than their non-aggregated monomers. Antimicrobial activity of peptide aggregates has to date been underexploited and it is found to be a very promising mechanism for peptide design. Detailed evidence for the molecular mechanisms involved are provided, based on super-resolution fluorescence microscopy, ss-NMR, AFM, neutron scattering/reflectivity, CD and Brewster angle microscopy.

Hepatitis C virus (HCV) infection correlates with human immune disorders characterized by abnormal activation and proliferation of lymphocytes. Interaction of HCV major envelope protein E2 with susceptible cells occurs at an early stage of the viral infection. HCV tropism for susceptible cells may elicit cellular signaling events implicated in the viral pathogenicity, and E2 protein is known to be responsible for the tropism. We documented previously that HCV E2 protein was capable of activating extracellular signal-regulated kinase (ERK) in human hepatoma Huh-7 cells. Here, ERK and p38 mitogen-activated protein kinase (MAPK) signaling pathways were investigated in human T lymphoma cell line Molt-4 in response to HCV E2 protein. Binding of HCV E2 protein to Molt-4 cells was detectable, and such interaction was a determinant for recognition and delivery of the E2 signal to intracellular pathways. Activation of ERK and p38 MAPK was specifically induced following the HCV E2-cell interaction. CD81 and low-density lipoprotein receptor (LDLR), proposed cellular receptors for HCV, were expressed naturally on Molt-4 cells. CD81 and LDLR were shown to mediate HCV E2-induced activation of ERK and p38 MAPK. In CD81-deficient U937 cells, levels of ERK and p38 MAPK activation and cell proliferation induced by HCV E2 protein were lower than those in Molt-4 cells. Furthermore, cell proliferation and secretion of interferon-gamma and interleukin-10 by Molt-4 cells were promoted by HCV E2 protein. Therefore, ERK and p38 MAPK signaling pathways were up-regulated by HCV E2 protein without synergetic stimulation, which was accompanied by alterations of cell behavior.

Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus that causes the most prevalent viral encephalitis in Asia. Since JEV is a neurotropic virus, it is important to identify key molecules that mediate JEV infection in neuronal cells and to investigate their underlying mechanisms. In this study, the critical role of Nedd4, an E3 ubiquitin ligase that is highly expressed in the central nervous system, was examined in JEV propagation. In SK-N-SH neuroblastoma cells, Nedd4 was up-regulated in response to JEV infection. Moreover, down-regulation of Nedd4 resulted in a significant decrease in JEV replication without alterations in virus attachment and internalization or in JEV pseudotyped virus infection, suggesting that Nedd4 participates in the replication but not in the entry stage of JEV infection. Further functional analysis showed that Nedd4 attenuated JEV-induced autophagy, which negatively regulates virus replication during infection. These results suggest that Nedd4 facilitates the replication of JEV by suppressing virus-induced autophagy. Taken together, our results indicate that Nedd4 plays a crucial role in JEV infection of neuronal cells, which provides a potential target for the development of novel treatment to combat JEV infection.

Objectives: Hepatitis C virus (HCV) F protein is a newly identified protein encoded by an alternative open reading frame that +1 overlaps core-encoding gene. It has been found that regulation of c-myc and p53 genes by HCV core protein is involved in liver cancer genesis. We wondered whether HCV F protein exerts similar or adverse regulatory effects on the transcription of c-myc and p53 genes. Methods: HCV F gene-containing, plasmid pcDNA3.1-F and HCV core gene-containing pcDNA3.1-C were constructed and transiently transfected into HepG₂ cells. Real-time quantitative PCR or Western blotting was used to determine the changes at transcription or translation levels of c-myc and p53 genes. Results: The transcription level of c-myc was much higher in pcDNA3.1-F transfected cells than those without plasmid transfected. Whereas the level of p53 transcription in pcDNA3.1-F transfected cells was lower than those in the parental cells. Moreover, levels of c-myc expression were up-regulated and those of p53 expression were down-regulated by HCV F protein. Conclusions: HCV F protein is of regulatory properties in cellular oncogene c-myc and anti-oncogene p53, which may be implicated in the formation of hepatocellular carcinoma.

In-cell NMR offers great insight into the characterization of the effect of toxins and antimicrobial peptides on intact cells. However, the complexity of intact live cells remains a significant challenge for the analysis of the effect these agents have on different cellular components. Here we show that 31P solid-state NMR can be used to quantitatively characterize the dynamic behaviour of DNA within intact live bacteria. Lipids were also identified and monitored, although 31P dynamic filtering methods indicated a range of dynamic states for phospholipid headgroups. We demonstrate the usefulness of this methodology for monitoring the activity of the antibiotic ampicillin and the antimicrobial peptide (AMP) maculatin 1.1 (Mac1.1) against Gram-negative bacteria. Perturbations in the dynamic behaviour of DNA were observed in treated cells, which indicated additional mechanisms of action for the AMP Mac1.1 not previously reported. This work highlights the value of 31P in-cell solid-state NMR as a tool for assessing the antimicrobial activity of antibiotics and AMPs in bacterial cells.

bStreptococcus suis serotype 2 (S. suis 2) is an important zoonotic pathogen that causes considerable economic losses to the pig industry and significantly threatens public health worldwide. The highly pathogenic S. suis 2, which contains the 89K pathogenicity island (PAI), has caused large-scale outbreaks of infections in humans, resulting in high mortality rates. In this study, we established two loop-mediated isothermal amplification (LAMP)-based assays that can rapidly detect S. suis 2 and the 89K PAI and can be performed simultaneously under the same conditions. Further, based on the findings of these two LAMP assays and using the same set of serially diluted DNA samples, we compared the sensitivities of different LAMP product detection methods, including SYBR green detection, gel electrophoresis, turbidimetry, calcein assays, and hydroxynaphthol blue detection. The results suggest that target genes can be amplified and detected within 48 min under 63°C isothermal conditions. The sensitivity of tests for S. suis 2 detection varies between detection methods and reaction systems, indicating that for each LAMP reaction system, multiple detection methods should be performed to select the optimal one. The sensitivities of the optimized methods (7.16 copies/reaction) in the present study were identical to those of the real-time PCR assay, and the test results for reference strains and clinical samples showed that these LAMP systems have high specificities. Thus, since the LAMP systems established in this study are simple, fast, and sensitive, they may have good clinical potential for detecting the highly pathogenic S. suis 2.