Revealing the molecular signatures of host-pathogen interactions.

Advances in sequencing technology and genome-wide association studies are now revealing the complex interactions between hosts and pathogen through genomic variation signatures, which arise from evolutionary co-existence

Oxygen-Glucose Deprivation Induced Glial Scar-Like Change in Astrocytes

It has been demonstrated that cerebral ischemia induces astrocyte reactivity, and subsequent glial scar formation inhibits axonal regeneration during the recovery phase. Investigating the mechanism of glial scar formation will facilitate the development of strategies to improve axonal regeneration. However, an in vitro model of ischemia-induced glial scar has not yet been systematically established.In the present study, we at the first time found that oxygen-glucose deprivation (OGD) in vitro can induce rat cortical astrocytes to present characteristics of glial scar. After OGD for 6 h, astrocytes showed a remarkable proliferation following 24 h reperfusion, evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and BrdU immunocytochemistry. Meanwhile, the expression of glial fibrillary acidic protein significantly increased, so did the expression of neurocan, which is a hallmark of the glial scar. In further experiments, neurons were co-cultured with astrocytes, which had been exposed to OGD, and then the immunostaining of class III β-tubulin was carried out to assess the neurite growth. When the co-culture was performed at 48 h reperfusion of astrocytes, the neurite growth was obviously inhibited, and this inhibition could be reversed by chondroitinase ABC, which digests glycosaminoglycan chains on CSPGs, including neurocan. However, the processes of neurons were elongated, when the co-culture was performed immediately after OGD.Our results indicated that after conditioned OGD the astrocytes presented the characteristics of the glial scar, which are also comparable to the astrocytes in acute and chronic phases after cerebral ischemia in vivo. Therefore, the present system may be used as an in vitro model to explore the mechanisms underlying glial scar formation and the treatments to improve axonal regeneration after cerebral ischemia

A Novel 5-Enolpyruvylshikimate-3-Phosphate Synthase Shows High Glyphosate Tolerance in Escherichia coli and Tobacco Plants

A key enzyme in the shikimate pathway, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) is the primary target of the broad-spectrum herbicide glyphosate. Identification of new aroA genes coding for EPSPS with a high level of glyphosate tolerance is essential for the development of glyphosate-tolerant crops. In the present study, the glyphosate tolerance of five bacterial aroA genes was evaluated in the E. coli aroA-defective strain ER2799 and in transgenic tobacco plants. All five aroA genes could complement the aroA-defective strain ER2799, and AM79 aroA showed the highest glyphosate tolerance. Although glyphosate treatment inhibited the growth of both WT and transgenic tobacco plants, transgenic plants expressing AM79 aroA tolerated higher concentration of glyphosate and had a higher fresh weight and survival rate than plants expressing other aroA genes. When treated with high concentration of glyphosate, lower shikimate content was detected in the leaves of transgenic plants expressing AM79 aroA than transgenic plants expressing other aroA genes. These results suggest that AM79 aroA could be a good candidate for the development of transgenic glyphosate-tolerant crops

Predictors of HIV and Syphilis among Men Who Have Sex with Men in a Chinese Metropolitan City: Comparison of Risks among Students and Non-Students

Men who have sex with men (MSM) are at a substantial risk of HIV, given rising HIV prevalence in urban China. Adolescent and adult students often take HIV-related risk as part of sexual exploration. We compared the risks of HIV and syphilis infections and risky sexual behaviors between student and non-student among urban MSM.Respondent driven sampling approach was used to recruit men who were self-identified as MSM in Chongqing Metropolitan City in southwestern China in 2009. Each participant completed a computer-assisted self-interview which collected demographic and behavioral data, and provided blood specimens for HIV and syphilis testing. Multivariable logistic regression analyses identified predictors for HIV and syphilis infections while comparing student and non-student MSM.Among 503 MSM participants, 36.4% were students, of whom 84.2% were in college. The adjusted prevalence of HIV infection was 5.5% (95% confidence interval [CI]: 2.1%-10.2%) in students and 20.9% (95% CI: 13.7%-27.5%) in non-students; the adjusted prevalence of syphilis was 4.4% (95% CI: 0.7%-9.0%) in students and 7.9% (95% CI: 3.6%-12.9%) in non-students (P = 0.12). Two groups had similar risky sexual behaviors such as number of sexual partners and exchanging sex for money. Multivariate analysis showed that students had lower HIV prevalence than non-students (adjusted odds ratio [AOR]: 0.3; 95% CI: 0.1-0.8) adjusting for age, ethnicity and other variables.Student MSM have lower HIV and similar syphilis prevalence compared with non-student MSM. However, due to a shorter duration of sexual experience and high prevalence of at-risk sexual behaviors among student MSM, HIV risk might be quite high in students as in non-students

MICA/B expression is inhibited by unfolded protein response and associated with poor prognosis in human hepatocellular carcinoma

BackgroundMICA/B are major ligands for NK cell activating receptor NKG2D and previous studies showed that the serum level of soluble MICA (sMICA) is an independent prognostic factor for advanced human hepatocellular carcinoma. However, the correlation between cellular MICA/B expression pattern and human hepatocellular carcinoma progression has not been well explored. The unfolded protein response is one of the main causes of resistance to chemotherapy and radiotherapy in tumor cells. However, whether the UPR in HCC could regulate the expression levels of MICA/B and affect the sensitivity of HCC cells to NK cell cytolysis has not been established yet.MethodsMICA/B expression pattern was evaluated by immunohistochemistry and Kaplan-Meier survival analysis was done to explore the relationship between MICA/B expression level and patient survival. The protein and mRNA expression levels of MICA/B in SMMC7721 and HepG2 cells treated by tunicamycin were evaluated by flow cytometry, Western Blot and RT-PCR. The cytotoxicity analysis was performed with the CytoTox 96 Non-Radioactive LDH Cytotoxicity Assay.ResultsMICA/B was highly expressed in human hepatocellular carcinoma and the expression level was significantly and negatively associated with tumor-node metastasis (TNM) stages. Patients with low level of MICA/B expression showed a trend of shorter survival time. The unfolded protein response (UPR) downregulated the expression of MICA/B. This decreased protein expression occurred via post-transcriptional regulation and was associated with proteasomal degradation. Moreover, decreased expression level of MICA/B led to the attenuated sensitivity of human HCC to NK cell cytotoxicity.ConclusionThese new findings of the connection of MICA/B, UPR and NK cells may represent a new concrete theory of NK cell regulation in HCC, and suggest that targeting this novel NK cell-associated immune evasion pathway may be meaningful in treating patients with HCC.Electronic supplementary materialThe online version of this article (doi:10.1186/s13046-014-0076-7) contains supplementary material, which is available to authorized users

Synthesis and electrochemical properties of nanostructured LiAIxMn2-xO4-yBry particles

Nanostructured LiAlxMn2−xO4−yBry particles were synthesized successfully by annealing the mixed precursors, which were prepared by room-temperature solid-state coordination method using lithium acetate, manganese acetate, lithium bromide, aluminum nitrate, citric acid, and polyethylene glycol 400 as starting materials. X-ray diffractometer patterns indicated that the particles of the as-synthesized samples are well-crystallized pure spinel phase. Transmission electron microscopy images showed that the LiAlxMn2−xO4−yBry samples consist of small-sized nanoparticles. The results of galvanostatic cycling tests revealed that the initial discharge capacity of LiAl0.05 Mn1.95O3.95Br0.05 is 119 mAh g−1; after the 100th cycle, its discharge capacity still remains at 92 mAh g−1. The introduction of Al and Br in LiMn2O4 bring a synergetic effect and is quite effective in increasing the capacity and elevating cycling performance