Tailored Aptamer-Based Visual Colorimetric Detection of Staphylococcal Enterotoxin A Using Gold Nanoparticles

Objective: To select and use aptamers as molecular recognition elements to construct a biosensor based on the salt effect of gold nanoparticles for the rapid quantitative detection of staphylococcal enterotoxin A (SEA). Methods: Molecular docking and molecular dynamics simulation were used to truncate the SEA aptamer and predict the results. The simulation results were verified colorimetrically using gold nanoparticles. The optimal SEA aptamer was used as the molecular recognition element. The reaction system was optimized, the relationship between SEA mass concentration and absorbance ratio was explored, and the accuracy, precision and specificity of the developed method were evaluated. Results: An SEA aptamer with short sequence, high affinity, strong specificity and stability was selected. This method was characterized by low limit of detection (LOD) and satisfactory recoveries for spiked samples. Conclusion: Molecular simulation can effectively improve the screening efficiency of aptamers, and the proposed method can be used for rapid detection of SEA

Limitations and Challenges of the Application of Phages in the Field of Microbial Food Safety

In recent years, an increasing number of studies have demonstrated the role of phages in controlling harmful microorganisms in foods. Due to their host specificity, phages are considered as an ideal tool to guarantee food safety. However, there are a series of limitations to the application of phages, so there have been few cases of the application of phages in the food industry. In this context, this paper discusses the frontier and hot issues in the application of phages in food safety, with a focus on the acceptability of the application of phages in the food industry, the potential risk of drug resistance transmission, the problem of phage resistance of bacteria, and the influence of complex food matrices on the effect of phages. Moreover, scientific and reasonable suggestions on the application of phages in the food industry are put forward. We hope that this review will promote the shift from basic research on phages to their application in the food industry

A Cost-Effective Approach to Optimizing Microstructure and Magnetic Properties in Ce17Fe78B6 Alloys

Optimizing fabrication parameters for rapid solidification of Re-Fe-B (Re = Rare earth) alloys can lead to nanocrystalline products with hard magnetic properties without any heat-treatment. In this work, we enhanced the magnetic properties of Ce17Fe78B6 ribbons by engineering both the microstructure and volume fraction of the Ce2Fe14B phase through optimization of the chamber pressure and the wheel speed necessary for quenching the liquid. We explored the relationship between these two parameters (chamber pressure and wheel speed), and proposed an approach to identifying the experimental conditions most likely to yield homogenous microstructure and reproducible magnetic properties. Optimized experimental conditions resulted in a microstructure with homogeneously dispersed Ce2Fe14B and CeFe2 nanocrystals. The best magnetic properties were obtained at a chamber pressure of 0.05 MPa and a wheel speed of 15 m·s−1. Without the conventional heat-treatment that is usually required, key magnetic properties were maximized by optimization processing parameters in rapid solidification of magnetic materials in a cost-effective manner

Serum biomarker panels for the diagnosis of gastric cancer

Abstract Gastric cancer is a leading cause of mortality due to neoplastic disease. Although early detection of gastric cancers can decrease the mortality rate, it remains a diagnostic challenge because of the lack of effective biomarkers. In this study, fifteen gastric cancer patients and ten healthy subjects were recruited to assess novel serum biomarkers for gastric cancer using antibody microarray technology. ELISA was utilized to validate the antibody array results. As a result, compared to the controls, eleven cytokines were found to be significantly increased in gastric cancer, including interferon gamma receptor 1 (IFNGR1), neurogenic locus notch homolog protein 3 (Notch‐3), tumor necrosis factor receptor superfamily member 19L (TNFRSF19L), growth hormone receptor (GHR), signaling lymphocytic activation molecule family 8 (SLAMF8), folate receptor beta (FR‐beta), integrin alpha 5, galectin‐8, erythropoietin‐producing hepatocellular A1 (EphA1), epiregulin, and fibroblast growth factor 12 (FGF‐12) with P < 0.05. ELISA validation supported the results of the antibody array. More importantly, most of these eleven cytokines, including IFNGR1, TNFRSF19L, GHR, SLAMF8, FR‐beta, and integrin alpha 5 were discovered to be elevated in gastric cancer serum samples for the first time in this study, suggesting that these proteins may serve as novel biomarkers for the early diagnosis and prognosis determination of gastric cancer

A Novel Matrine Derivative WM130 Inhibits Activation of Hepatic Stellate Cells and Attenuates Dimethylnitrosamine-Induced Liver Fibrosis in Rats

Activation of hepatic stellate cells (HSCs) is a critical event in process of hepatic fibrogenesis and cirrhosis. Matrine, the active ingredient of Sophora, had been used for clinical treatment of acute/chronic liver disease. However, its potency was low. We prepared a high potency and low toxicity matrine derivate, WM130 (C30N4H40SO5F), which exhibited better pharmacological activities on antihepatic fibrosis. This study demonstrated that WM130 results in a decreased proliferative activity of HSC-T6 cells, with the half inhibitory concentration (IC50) of 68 μM. WM130 can inhibit the migration and induce apoptosis in HSC-T6 cells at both concentrations of 68 μM (IC50) and 34 μM (half IC50). The expression of α-SMA, Collagen I, Collagen III, and TGF-β1 could be downregulated, and the protein phosphorylation levels of EGFR, AKT, ERK, Smad, and Raf (p-EGFR, p-AKT, p-ERK, p-Smad, and p-Raf) were also decreased by WM130. On the DMN-induced rat liver fibrosis model, WM130 can effectively reduce the TGF-β1, AKT, α-SMA, and p-ERK levels, decrease the extracellular matrix (ECM) formation, and inhibit rat liver fibrosis progression. In conclusion, this study demonstrated that WM130 can significantly inhibit the activation of HSC-T6 cells and block the rat liver fibrosis progression by inducing apoptosis, suppressing the deposition of ECM, and inhibiting TGF-β/Smad and Ras/ERK pathways

Opposite effective connectivity in the posterior cingulate and medial prefrontal cortex between first-episode schizophrenic patients with suicide risk and healthy controls.

OBJECTIVE: The schizophrenic patients with high suicide risk are characterized by depression, better cognitive function, and prominent positive symptoms. However, the neurobiological basis of suicide attempts in schizophrenia is not clear. The suicide in schizophrenia is implicated in the defects in emotional process and decision-making, which are associated with prefrontal-cingulate circuit. In order to explore the possible neurobiological basis of suicide in schizophrenia, we investigated the correlation of prefrontal-cingulate circuit with suicide risk in schizophrenia via dynamic casual modelling. METHOD: Participants were 33 first-episode schizophrenic patients comprising of a high suicide risk group (N = 14) and a low suicide risk group (N = 19). A comparison group of healthy controls (N = 15) were matched for age, gender and education. N-back tasking functional magnetic resonance imaging data was collected. RESULTS: Compared with healthy controls group, the two patients groups showed decreased task-related suppression during 2-back task state versus baseline state in the left posterior cingulate and medial prefrontal cortex; the hyper-connectivity from the left posterior cingulate cortex to the left medial prefrontal cortex existed in both schizophrenic patients groups, but hypo-connectivity in the opposite direction only existed in the schizophrenic patients group with high suicide risk. CONCLUSIONS: The hyper-connectivity from the left posterior cingulate cortex to the left medial prefrontal cortex may suggest that the abnormal effective connectivity was associated with risk for schizophrenia. The hypo-connectivity in the opposite direction may represent a possible correlate of increased vulnerability to suicide attempt

Candida causes recurrent vulvovaginal candidiasis by forming morphologically disparate biofilms on the human vaginal epithelium

Background: Recurrent vulvovaginal candidiasis (RVVC) is a recalcitrant medical condition that affects many women of reproductive age. The importance of biofilm formation by Candida in RVVC has been recently questioned. This study aimed to elucidate the fundamental growth modes of Candida in the vagina of patients with RVVC or sporadic vulvovaginal candidiasis (VVC) and to assess their roles in the persistence of RVVC. Methods: Vaginal tissues were sampled from twelve patients clinically and microbiologically diagnosed as RVVC or VVC at a post-antifungal-treatment and asymptomatic period. High-resolution scanning electron microscopy, fluorescence in situ hybridization in combination with Candida-specific 18S rRNA probes and viable fungal burden were used to qualitatively and quantitatively evaluate Candida growth in the human vagina. The presence of Candida biofilm extracellular polymeric substances was examined using confocal laser scanning microscopy and biopsy sections pre-stained with Concanavalin A. Histopathological analysis was carried out on infected vaginal tissues stained with hematoxylin and eosin. Lastly, the susceptibility of epithelium-associated Candida biofilms to fluconazole at the peak serum concentration was evaluated. Results: Candida species grew on the vaginal epithelium of RVVC patients as morphologically disparate biofilms including monolayers, microcolonies, and macro-colonies, in addition to sporadic adherent cells. Candida biofilm growth on the vaginal epithelium was associated with mild lymphocytic infiltration of the vaginal mucosa. These epithelium-based Candida biofilms presented an important characteristic contributing to the persistence of RVVC that is the high tolerance to fluconazole. Conclusions: In summary, our study provides direct evidence to support the presence of Candida biofilms in RVVC and an important role of biofilm formation in disease persistence

Five hypothesized dynamic casual models during 2-back task.

<p>Each model includes the left medial prefrontal cortex (MPFC) and the ipsilateral posterior cingulate cortex (PCC), in which the arrows indicate extrinsic stimulation and functional connections direction. M1, M2 and M3 comprised bi-directional connections with respectively driving input into PCC or MPFC or both of the regions. M4 only contained unidirectional connection from the PCC to MPFC with driving input into PCC and M5 was completely opposite to M4. M1, M4 and M2 were identified as the optimal models in HSR, LSR and HC respectively. HSR: schizophrenic patients with high suicide risk; LSR: schizophrenic patients with low suicide risk; HC: healthy controls.</p

Regions with significant activations at rest state compared with 2-back task (<i>p</i><0.05, FWE corrected).

<p>Regions with significant activations at rest state compared with 2-back task (<i>p</i><0.05, FWE corrected).</p