Determination of Whole Molecular of Thermostable Direct Hemolysins in Milk Powder by HPLC-ESI-TOF.

Although Vibrio parahaemolyticus (V. parahaemolyticus) is a pathogen frequently found in seafood, there is a possibility of its presence in other foods, such as dairy products. The main virulence factors of V. parahaemolyticus are thermostable direct hemolysins (TDHs) which are lethal toxins, so it is necessary to establish qualitative and quantitative methods for determining TDHs. HPLC-ESI-TOF was employed to establish a method for identifying TDHs. The identification and quantification ions of TDHs were confirmed by HPLC-ESI-TOF. The method was developed for detecting TDHs in milk powder using HPLC-ESI-TOF in this paper, and limits of detection (were between 0.20 and 0.40 mg/kg, limits of quantitation were between 0.5 and 1.0 mg/kg and recoveries of all TDHs were between from 78% to 94% with relative standard deviation lower than 10%. This research will provide a reference for developing methods of HPLC-MS/MS to detect TDHs in food samples, which can provide a tool for the government to monitor TDHs contamination in foods.

Effect of environmental factors on expression of staphylococcal enterotoxin genes.

Staphylococcal enterotoxins (SEs) secreted by Staphylococcus aureus (S. aureus) can cause foodborne disease, nausea, vomiting and diarrhea, and even death. Regulation of SE expression is related to accessory gene regulators (Agr). It is important to reveal which environmental factors influence regulation of SE expression to prevent SE food poisoning outbreak. Hence, natural environmental factors which may have an impact on SE expression were selected, such as temperature, food types, strains, and competing strains. Seven strains of S. aureus carrying different SE genes were collected from the Chinese Academy of Inspection and Quarantine (CAIQ) strain bank for study. Strains were cultured with different conditions. Temperature was 8 °C, 22 °C, and 30 °C. Food type was milk powder and nutrient broth. Competing strains were Vibrio parahaemolyticus (V. parahaemolyticus), Escherichia coli (E. coli), and Bacillus cereus (B. cereus). The expression culture solution was pretreated by centrifugation, then determined by using SDS-PAGE, and distinguished SEs apart from each other by HPLC-ESI-TOF. There are 168 samples collected from SE expression culture; the result of SDS-PAGE suggests 23 samples were positive for SEs, and the other 145 samples were negative for SEs. The result of HPLC-ESI-TOF suggests that SEs with similar molecular weight can be distinguished in terms of m/z. The most important factor contributing to regulate expression of SEs was estimated by logistic regressive analysis. The result shows that McFadden R2 is 0.213; p value is 0.000 (p < 0.05); this result illustrates that the model is valid and meaningful. Strains, food types, temperature, and competing strands can explain the 21% change in SE expression. Temperature (z = 3.029, p = 0.002 < 0.01), strains (z = - 3.132, p = 0.002 < 0.01), and food types (z = - 2.415, p = 0.016 < 0.05) have significant impact on SE expression, and the competing strains (z = 1.230, p = 0.219 > 0.05) have no impact on the SE expression. More important impact on SE expression was estimated by OR value; the result shows that strength of temperature influencing on SE expression is bigger than strains and food types in terms of values of OR, temperature (OR = 2.862), strains (OR = 0.641), and food types (OR = 0.561); consequently, temperature is a key factor for stimulating SE expression and had high expression at 30 °C. Therefore, food easily contaminated with S. aureus should be monitored intensively at early and late summer, when proper temperature for expressing SEs may result in S. aureus food poisoning prevalence.

Investigation on Potential Biomarkers and Immune-Related Mechanisms of Ischemic Stroke.

BACKGROUND: This study aimed to reveal the detailed immune-related mechanisms underlying ischemic stroke (IS) and identify new immune-associated biomarkers for clinical management. METHODS: Differentially expressed genes (DEGs) between IS samples and normal controls were identified using the GSE16561 dataset. The feature genes of the immune cells were investigated using the GSE72642 dataset. Weighted correlation network analysis (WGCNA) was performed to reveal module genes, followed by an investigation of common DEGs and a functional enrichment analysis. Potential biomarkers were identified based on hub genes in protein-protein interaction networks and WGCNA. Finally, GSE158312 was used for biomarker verification. RESULTS: In total, 1230 DEGs were identified between the IS samples and normal controls. Seven clinically significant modules were identified using WGCNA. The yellow module genes were positively correlated with polymorphonuclear cells (PMNC), whereas the brown module genes were positively correlated with CD4+ T cells. Eight genes were selected as hub genes. These genes are mainly involved in functions such as the innate immune response. Upregulated TLR2 and ARG1 levels were significantly different between the two groups in the verification dataset. CONCLUSIONS: Our findings suggest ARG1 and TLR2 as novel biomarkers for IS. Upregulated TLR2 might play a role in IS development by participating in the innate immune response function.

Novel Fe-Based Amorphous Composite Coating with a Unique Interfacial Layer Improving Thermal Barrier Application.

To improve thermal barrier applications in advanced vehicle engines, a novel Fe-based amorphous composite coating was designed by introducing ceramic oxides and was prepared by atmospheric plasma spraying (APS). The microstructure and related properties of the as-deposited coating were investigated in detail. The composite coating comprises a well-formed FeCrNbBSi amorphous metallic matrix and dispersed yttria-stabilized zirconia (YSZ) splats. A unique Si-oxide interfacial layer with a thickness of several nanometers and an amorphous structure forms between the metallic matrix and ceramic phase, which is attributed to a combination of multiple effects. The composite coating displays extremely low thermal conductivity from 2.28 W/mK at 100 °C to 3.36 W/mK at 600 °C and can increase the surface temperature of the piston crown by 18.93 °C, which implies a significant means of enhancing the power efficiency. The improved thermal barrier ability of the composite coating is revealed as the crucial effect of the Si-oxide interfacial layer, which induces an increased interfacial thermal resistance. The fracture toughness of the composite coating remains at 3.40 MPa·m1/2, comparable to that of the monolithic amorphous coating, 3.74 MPa·m1/2, which is closely related to the formation of a Si-oxide layer and its nanoscale thickness. Therefore, the Fe-based amorphous composite coating developed here demonstrates great potential as an innovative metal-based thermal barrier coating for application in vehicle engines and provides specific inspiration for future works exploring the interfacial engineering of coating.

Maize membrane-bound transcription factor Zmbzip17 is a key regulator in the cross-talk of ER quality control and ABA signaling.

Abiotic stresses disrupt protein folding and induce endoplasmic reticulum (ER) stress, which in turn activates the unfolded protein response (UPR) to aid in the refolding or degradation of misfolded proteins. The phytohormone ABA regulates many aspects of plant development and plays a central role in the stress response; however, the role of ABA in transducing stress signals to activate the UPR has not been recognized. In this study, a gene encoding the maize ortholog of AtbZIP17, a transmembrane transcription factor functioning as an ER stress transducer, was identified from the MaizeGDB database, and designated ZmbZIP17. ZmbZIP17 was induced by both ABA and ER stress-eliciting agents such as dithiotreitol (DTT) and tunicamycin (TM). Transiently expressed yellow fluorescent protein (YFP)-ZmbZIP17 co-localized with the ER marker HDEL-mCherry under control conditions, but partially translocated into the nucleus upon TM treatment or removal of the transmembrane domain. TM-induced processing of ZmbZIP17 was confirmed by Western blot analysis. When overexpressed in Arabidopsis, ZmbZIP17 triggered ER stress response gene expression and tolerance to DTT and TM, elevated ABA-responsive gene expression and ABA sensitivity both pre- and post-germination. Additionally, ABA was found to induce ER stress response gene expression, alone or synergistically with ZmbZIP17, in the absence of DTT or TM; while ZmbZIP17 was capable of interacting with ABA-responsive cis-elements (ABREs) that exist in promoters of known ABA-responsive genes. Together, our results reveal a direct link between ER stress and ABA signaling pathways involving the ZmbZIP17 transcription factor.