Research progress of visual detection in rapid on-site detection of pathogen nucleic acid.

Nucleic acid detection is widely used in pathogen screening and detection due to its high sensitivity and specificity. With the increase of detection requirements and the development of amplification technology, nucleic acid detection methods are gradually developing towards simple, fast and low-cost. Quantitative polymerase chain reaction (qPCR), as the "gold standard" for nucleic acid detection, relies on expensive equipment and professional operators, which is not suitable for rapid on-site detection of pathogens. The visual detection method without relying on excitation light source or complex equipment can present the detection results in a more intuitive and portable way after combining with rapid and efficient amplification technology, which has the potential of point-of-care testing (POCT). This paper focuses on the reported application of amplification technology and CRISPR/Cas technology in visual detection and compares their advantages and disadvantages, so as to provide reference for POCT strategy based on pathogen nucleic acid.

High-level expression and characterization of a thermostable xylanase mutant from Trichoderma reesei in Pichia pastoris.

A gene encoding xylanase 2 mutant from Trichoderma reesei (T2C/T28C, named mxyn2) was cloned into the Pichia pastoris X33 strain using the vector pPICZαA. Recombinant Mxyn2p was functionally expressed in P. pastoris X33 and secreted into the supernatant. Real time qPCR demonstrated that an increase in gene copy number correlated with higher levels of expression. Supernatant from methanol induced cells was concentrated by ultrafiltration with a 10kDa cut off membrane, and purified with ion exchange chromatography using SP Sepharose Fast Flow chromatography. Recombinant Mxyn2p protein had the highest activity at 75°C, while recombinant protein encoded by the "wild type" xylanase gene xyn2, also expressed in Pichia, was 20°C lower. The Mxyn2p enzyme retained more than 70% of its activity after incubation at 80°C for 10min. The effects of the optimal pH and temperature for higher expression levels in P. pastoris were also determined, 6.0 and 22°C, respectively. The maximum xylanase activity of Mxyn2p was 13,000nkat/mg (9.88g/l) in fed-batch cultivation after 168h induction with methanol in a 50l bioreactor.

High-level expression of pro-form lipase from Rhizopus oryzae in Pichia pastoris and its purification and characterization.

A gene encoding Rhizopus oryzae lipase containing prosequence (ProROL) was cloned into the pPICZαA and electrotransformed into the Pichia pastoris X-33 strain. The lipase was functionally expressed and secreted in Pichia pastoris with a molecular weight of 35 kDa. The maximum lipase activity of recombinant lipase (rProROL) was 21,000 U/mL, which was obtained in a fed-batch cultivation after 168 h induction with methanol in a 50-L bioreactor. After fermentation, the supernatant was concentrated by ultrafiltration with a 10 kDa cut off membrane and purified with ion exchange chromatography using SP Sepharose Fast Flow chromatography. The optimum pH and temperature of the rProROL were pH 9.0 and 40 °C, respectively. The lipase was stable from pH 4.0 to 9.0 and from 25 to 55 °C. The enzyme activity was enhanced by Ca(2+) and inhibited by Hg(2+) and Ag(+). The lipase showed high activity toward triglyceride-Tripalmitin (C16:0) and triglyceride-Trilaurin (C12:0).

Association Between Sleep Duration and Stroke in Different Status of Metabolic Syndrome: A Cross-Sectional Study in Shanghai Adult Residents.

Purpose: This study aimed to investigate the relationship between sleep duration (SD) and stroke, and examine the effects of SD on stroke with or without metabolic syndrome (Mets) and its components among the adult residents in Shanghai, China. Participants and Methods: A total of 20,245 participants (51.72% male, mean age 44.66 years) were included from Shanghai Chronic Disease and Risk Factors Surveillance (SCDRFS) in 2017. The weighted logistic regressions were performed to examine the associations between SD and stroke in different status of Mets and its components. Results: The mean SD was 7.51±0.03 h/d. After adjusting for all the potential factors, SD<6 h/d (OR=1.73, 95% CI: 1.35-2.20) or ≥10 h/d (OR=1.66, 95% CI: 1.08-2.57) was significantly positively associated with stoke in the total participants; moreover, in the non-Mets group, only SD<6 h/d (OR=1.77, 95% CI: 1.19, 2.64) significantly increased the risk of stroke; while, in the Mets group, SD<6 h/d (OR=1.80, 95% CI:1.17-2.76) and ≥10 h/d (OR=1.97, 95% CI: 1.00-3.88) both had a positive significantly association with stoke. In addition, the effects of SD<6 h/d on stroke were more pronounced among those with high WC (OR=2.24, 95% CI: 1.40-3.58) and high TG (OR=2.60, 95% CI: 1.86-3.62), and the effects of SD≥10 h/d on stroke were more evident among those with high TG (OR=2.28, 95% CI: 1.02-5.08) and high FBG (OR=2.58, 95% CI: 1.30-5.10). Conclusion: Both short and long SD were significantly positively associated with stroke in the total participants, and the associations were stronger in the Mets group; conversely, in the non-Mets group, only short SD was significantly positively associated with stroke, and no significant association was observed between long SD and stroke. Therefore, more precise sleep measures may be needed to prevent stroke according to the different status of Mets.

High-frequency repetitive transcranial magnetic stimulation protects against cerebral ischemia/reperfusion injury in rats: Involving the mitigation of ferroptosis and inflammation.

BACKGROUND AND AIM: Repetitive transcranial magnetic stimulation (rTMS) has been found to attenuate cerebral ischemia/reperfusion (I/R) injury. However, its effects and mechanism of action have not yet been clarified. It has been reported that cerebral I/R injury is closely associated not only with ferroptosis but also with inflammation. Hence, the current study aimed to investigate whether high-frequency rTMS attenuates middle cerebral artery occlusion (MCAO)-induced cerebral I/R injury and further to elucidate the mediatory role of ferroptosis and inflammation. METHODS: The protective effects of rTMS on experimental cerebral I/R injury were investigated using transient MCAO model rats. Neurological scores and pathological changes of cerebral ischemic cortex were assessed to evaluate the effects of rTMS on cerebral I/R injury. The involvement of ferroptosis and that of inflammation were examined to investigate the mechanism underlying the effects of rTMS. RESULTS: High-frequency rTMS remarkably rescued the MCAO-induced neurological deficits and morphological damage. rTMS treatment also increased the mRNA and protein expression of glutathione-dependent peroxidase 4, decreased the mRNA and protein levels of acyl-CoA synthetase long-chain family member 4 and transferrin receptor in the cortex. Moreover, rTMS administration reduced the cerebrospinal fluid IL-1ß, IL-6, and TNF-α concentrations. CONCLUSION: These findings implicated that high-frequency rTMS alleviates MCAO-induced cerebral I/R injury, and the underlying mechanism could involve the inhibition of ferroptosis and inflammation. Our study identifies rTMS as a promising therapeutic agent for the treatment of cerebral I/R injury. Moreover, the mechanistic insights into ferroptosis and inflammation advance our understanding of it as a potential therapeutic target for diseases beyond cerebral ischemia stroke.

Comparing high-dose dual therapy with bismuth-containing quadruple therapy for the initial eradication of Helicobacter pylori infection on Hainan Island: A randomized, multicenter clinical trial.

BACKGROUND: Traditional bismuth-containing quadruple therapy, as a first-line eradication treatment for Helicobacter pylori (H. pylori), has several disadvantages, including drug side effects, low medication adherence, and high costs. Trials of high-dose dual treatment have demonstrated its advantages, which include good safety and adherence profiles. In this study, we investigated the efficacy, safety, and compliance of a high-dose dual therapy when compared with bismuth-based quadruple treatment for the initial eradication of H. pylori infection on Hainan Island, China. METHODS: We randomized 846 H. pylori-infected patients into two groups. A bismuth-containing quadruple therapy group was administered the following: esomeprazole 20 mg, amoxicillin 1000 mg, and clarithromycin 500 mg twice daily, and colloidal bismuth pectin in suspension 150 mg three times/day for 2 weeks. A high-dose dual therapy group was administered the following: esomeprazole 20 mg four times/day and amoxicillin 1000 mg three times/day for 2 weeks. Patients were given a 13C urea breath test at 4 weeks at treatment end. Adverse effects and compliance were evaluated at follow-up visits. RESULTS: Eradication rates in the high-dose dual therapy group were: 90.3% (381/422, 95% confidence interval [CI]: 87.1%-92.9%) in intention-to-treat (ITT) and 93.6% (381/407, 95% CI: 90.8%-95.8%) in per-protocol (PP) analyses. Eradication rates were 87.3% in ITT (370/424, 95% CI: 83.7%-90.3%) and 91.8% in PP analyses (370/403, 95% CI: 88.7%-94.3%) for quadruple therapy, with no statistical differences (P = 0.164 in ITT and P = 0.324 in PP analyses). Adverse effects were 13.5% (55/407) in the dual group and 17.4% (70/403) in the quadruple group (P = 0.129). Compliance was 92.4% (376/407) in the dual group and 86.6% (349/403) in the quadruple group (P = 0.007). CONCLUSIONS: High-dose dual therapy had high eradication rates comparable with bismuth-based quadruple treatment, with no differences in adverse effects, however higher adherence rates were recorded.

[Effect of electroacupuncture at "Shuigou" (GV26) and "Baihui" (GV20) on autophagy of hippo-campal neurons in rats with cerebral ischemia-reperfusion injury].

OBJECTIVE: To explore the effect of electroacupuncture (EA) at "Shuigou"(GV6) and "Baihui"(GV20) on autophagy of hippocampal neurons in cerebral ischemia-reperfusion (I/R) injury rats. METHODS: Forty-eight healthy male SD rats were randomly divided into sham operation, model and EA groups, with 16 rats in each group. The rat model of cerebral I/R injury was established by occlusion of the middle cerebral artery (MCAO). Rats of the EA group received EA at GV26 and GV20 for 20 min, once daily for 5 days. The neurological function of rats in each group was evaluated by Longa neurological function score. The cerebral infarction volume was measured by TTC staining. The levels of IL-6, IL-18 and TNF-α in cerebrospinal fluid were detected by ELISA. Real-time PCR and Western blot were respectively used to detect the expressions of autophagy-related proteins AMPK, Beclin-1, VPS34 and LC3B. RESULTS: Compared with the sham operation group, neurological function scores of rats in the model group were significantly increased (P<0.01); the volume of cerebral infarction was significantly increased (P<0.01); the contents of IL-6, IL-18 and TNF-α in cerebrospinal fluid were increased (P<0.01, P<0.05); the mRNA expression levels of AMPK, Beclin-1, VPS34 and LC3B were significantly increased (P<0.01); the protein expressions of AMPK, Beclin-1, VPS34 and the ratio of LC3B-Ⅱ/LC3B-Ⅰ were increased (P<0.01, P<0.05). After intervention and in comparison with the model group, the neurological function scores were decreased (P<0.05); the cerebral infarct volume were decreased (P<0.05); the contents of IL-6, IL-18 and TNF-α in cerebrospinal fluid were decreased (P<0.05); the mRNA expressions of AMPK, Beclin-1, VPS34 and LC3B were significantly decreased (P<0.01); the protein expressions of AMPK, Beclin-1, VPS34 and the ratio of LC3B-Ⅱ/LC3B-Ⅰ were decreased (P<0.05, P<0.01). CONCLUSION: EA can improve the neurological function and alleviate the degree of nerve injury in rats with cerebral I/R injury, which may be related to inhibiting the autophagy level of hippocampal neurons.

Treatment with MQA, a Derivative of Caffeoylquinic Acid, Provides Neuroprotective Effects against Cerebral Ischemia Through Suppression of the p38 Pathway and Oxidative Stress in Rats.

1,5-O-dicaffeoyl-3-O-(4-malic acid methylester)-quinic acid (MQA), extracted from Arctium lappa L., has been observed to exert neuroprotective effects in vitro. The aim of this study was to investigate whether MQA is an effective therapeutic method for cerebral ischemic injury in vivo. In this study, adult male rats were randomly divided into four groups: a normal group, a model group subjected to middle cerebral artery occlusion (MCAO) for 24 h, a model + MQA group (which received intragastric MQA for the 7 days prior to MCAO), and a model + positive drug group. MQA appeared to induce effects in cerebral ischemic injury in rats, by downregulating malondialdehyde, glutathione peroxidase, and nitric oxide synthase levels. Treatment with MQA significantly reduced infarcted sections. In addition, caspase-3 and Iba1 protein expression were evaluated with immunohistochemistry, and cortical cell apoptosis was assessed with terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assays. Expression of AKT and Bax, ERK1/2, P38 and Bcl-2, NFkB1, PARP, and caspase-3 was assessed with Western blotting. We found Bcl-2 and NFkB1 (p50) expressions were upregulated, whereas the expression of PARP, caspase-3, NFkB1 (p105), ERK1/2, P38, AKT, and Bax was downregulated. In conclusion, we observed MQA was an effective treatment for cerebral ischemic injury in rats.

Codon Optimization Significantly Improves the Expression Level of α -Amylase Gene from Bacillus licheniformis in Pichia pastoris.

α-Amylase as an important industrial enzyme has been widely used in starch processing, detergent, and paper industries. To improve expression efficiency of recombinant α-amylase from Bacillus licheniformis (B. licheniformis), the α-amylase gene from B. licheniformis was optimized according to the codon usage of Pichia pastoris (P. pastoris) and expressed in P. pastoris. Totally, the codons encoding 305 amino acids were optimized in which a total of 328 nucleotides were changed and the G+C content was increased from 47.6 to 49.2%. The recombinants were cultured in 96-deep-well microplates and screened by a new plate assay method. Compared with the wild-type gene, the optimized gene is expressed at a significantly higher level in P. pastoris after methanol induction for 168 h in 5- and 50-L bioreactor with the maximum activity of 8100 and 11000 U/mL, which was 2.31- and 2.62-fold higher than that by wild-type gene. The improved expression level makes the enzyme a good candidate for α-amylase production in industrial use.