Real-time Fluorescence Quantitative PCR Method Research Articles

B-205 Performance of a Novel Fluorogenic Assay for Detection of Carbapenemase-producing Enterbacteriaceae

Abstract Background In recent years, under the selective challenge of antibiotics, the variety and number of drugresistant pathogenic microorganisms have increased significantly, which brings great challenges to clinical diagnosis and treatment, especially the infection caused by carbapenem resistant Enterobacteriaceae (CRE). Carbapenemases production is the main mechanism of drug resistance of Enterobacteriaceae to carbapenems. Drug resistance of Carbapenems can be caused by three mechanisms, resulting in the production of five major Carbapenemases. These are Klebsiella pneumoniae enzyme (KPC), New Delhi metal β-lactamase (NDM), carbapenem hydrolyzed oxalase (OXA-48 like), integrin-encoded metal β- lactamase (VIM) and IMP (Imipenemase). The real-time fluorescence quantitative PCR (qPCR) method based on molecular beacons was combined with the melting curve analysis to identify five drug resistance genes simultaneously by a single PCR reaction, with rapid detection, high sensitivity and strong specificity. Based on this principle, we developed the novel fluorogenic assay for rapid detection of Carbapenemases in multidrug-resistant Enterobacteriaceae (Dynamiker Biotechnology (Tianjin) Co., Ltd.). Methods We evaluated the performance of the novel fluorogenic assay for rapid detection of Carbapenemases in multidrug-resistant Enterobacteriaceae, including the limit of detection (LoD) and cross-reactivity, and compared it with the lateral flow immunochromatography assay (LFA). Results The LoD ranged from 75-450 CFU/mL for the five carbapenemase genes. The analytical specificity for target genes was 100%, as assessed with a panel of 15 pathogens, which indicated no cross-reactions. Comparison of qPCR and LFA results from twenty-three CRE clinical isolates with characterized carbapenemase content demonstrated a complete agreement (Table 1). Conclusions The novel fluorogenic assay for rapid detection of Carbapenemases in multidrug-resistant Enterobacteriaceae is an accurate and rapid method to identify KPC, NDM, VIM, IMP and OXA-48-like carbapenemases in the clinical microbiology laboratory, which can guide infection control programs to limit the spread of these organisms.

Development of a highly sensitive TaqMan method based on multi-probe strategy: its application in ASFV detection.

The establishment of high sensitive detection method for various pathogenic microorganisms remains constantly concerned. In the present study, multi-probe strategy was first systematically investigated followed by establishing a highly sensitive TaqMan real-time fluorescent quantitative PCR (qPCR) method for detecting African swine fever virus (ASFV). Briefly, four probes based on the B646L gene of ASFV were designed and the effects of different combinations of the probes in a single TaqMan qPCR assay on the detection sensitivity were investigated. As less as 0.5-5 copies/μl of the ASFV gene was detected by the established TaqMan qPCR assay. Furthermore, plasmid harboring the B646L in water samples could be concentrated 1000 times by ultrafiltration to enable a highly sensitive detection of trace viral nucleic acids. Moreover, no cross-reactivity was observed with other common clinical swine viruses such as PCV2, PCV3, PCV4, PEDV, PDCoV, CSFV, PRRSV, and PRV. When detecting 173 clinical porcine serum samples, the coincidence rate between the developed method and WOAH (World Organization of Animal Health) recommended method was 100%. This study might provide an integrated strategy to achieve higher detection sensitivity of trace pathogenic microorganisms and applicably sensitive TaqMan-based qPCR assays.

A multiplex real-time fluorescence-based quantitative PCR assay for calf diarrhea viruses.

Calf diarrhea is a significant condition that has a strong effect on the cattle industry, resulting in huge economic losses annually. Bovine torovirus (BToV), bovine enterovirus (BEV), bovine norovirus (BNoV), bovine coronavirus (BCoV), bovine rotavirus (BRV), and bovine viral diarrhea virus (BVDV) are key pathogens that have been implicated in calf diarrhea. Among these viruses, there remains limited research on BToV, BEV, and BNoV, with no available vaccines or drugs for their prevention and control. Although commercial vaccines exist for BCoV, BRV, and BVDV, the prevalence of these diseases remains high. To address this issue, we developed a multiplex real-time fluorescence quantitative PCR method for detecting BToV, BEV, BNoV, BCoV, BRV, and BVDV. This method can be used to effectively monitor the prevalence of these six viruses and serve as a reference for future prevention and control strategies. In this study, we specifically designed primers and probes for the BNoV Rdrp, BEV 5'UTR, BToV M, BCoV N, BRV NSP5, and BVDV 5'UTR genes. This method was determined to be efficient, stable, and sensitive. The lowest detectable levels of plasmids for BNoV, BEV, BToV, BRV, BCoV, and BVDV were 1.91 copies/μL, 96.0 copies/μL, 12.8 copies/μL, 16.4 copies/μL, 18.2 copies/μL, and 65.3 copies/μL, respectively. Moreover, the coefficients of variation for all six detection methods were < 3%; they also exhibited a strong linear relationship (R2 ≥ 0.98), and an amplification efficiency of 90%-110%. A total of 295 fecal and anal swabs were collected from calves with diarrhea in Guangdong, China. The positive rates for BToV, BEV, BNoV, BCoV, BR, and BVDV were determined to be 0.34% (1/295), 6.10% (18/295), 0.68% (2/295), 1.36% (4/295), 10.85% (32/295), and 2.03% (6/295), respectively. Notably, BEV and BRV exhibited the highest prevalence. Additionally, this study identified the occurrence of BToV and BNoV in Guangdong for the first time. In summary, this study successfully established an effective method for detecting several important bovine viruses; ultimately, this holds strong implications for the future development of the cattle industry.

The Identification of the Banana Endogenous Reference Gene MaSPS1 and the Construction of Qualitative and Quantitative PCR Detection Methods.

Endogenous reference genes play a crucial role in the qualitative and quantitative PCR detection of genetically modified crops. Currently, there are no systematic studies on the banana endogenous reference gene. In this study, the MaSPS1 gene was identified as a candidate gene through bioinformatics analysis. The conservation of this gene in different genotypes of banana was tested using PCR, and its specificity in various crops and fruits was also examined. Southern blot analysis showed that there is only one copy of MaSPS1 in banana. The limit of detection (LOD) test showed that the LOD of the conventional PCR method is approximately 20 copies. The real-time fluorescence quantitative PCR (qPCR) method also exhibited high specificity, with a LOD of approximately 10 copies. The standard curve of the qPCR method met the quantitative requirements, with a limit of quantification (LOQ) of 1.14 × 10-2 ng-about 20 copies. Also, the qPCR method demonstrated good repeatability and stability. Hence, the above results indicate that the detection method established in this study has strong specificity, a low detection limit, and good stability. It provides a reliable qualitative and quantitative detection system for banana.

Two Molecular Plasma-Based Diagnostic Methods to Evaluate Early Infection of Schistosoma japonicum and Schistosomiasis Japonica.

The prevalence and infectious intensity of schistosomiasis japonica has decreased significantly in China in the past few decades. However, more accurate and sensitive diagnostic methods are urgently required for the further control, surveillance, and final elimination of the disease. In this study, we assessed the diagnostic efficacy of a real-time fluorescence quantitative PCR (qPCR) method and recombinase polymerase amplification (RPA) combined with a lateral-flow dipstick (LFD) assay for detecting early infections of Schistosoma japonicum and different infection intensities. The sensitivity of the qPCR at 40 days post-infection (dpi) was 100% (8/8) in mice infected with 40 cercariae, which was higher than in mice infected with 10 cercariae (90%, 9/10) or five cercariae (77.8%, 7/9). The results of the RPA-LFD assays were similar, with sensitivities of 55.6% (5/9), 80% (8/10), and 100% (8/8) in mice infected with 5, 10, and 40 cercariae, respectively. In goats, both the qPCR and RPA-LFD assays showed 100% (8/8) sensitivity at 56 dpi. In the early detection of S. japonicum infection in mice and goats with qPCR, the first peak in positivity appeared at 3-4 dpi, when the positivity rate exceeded 40%, even in the low infection, intensity mice. In the RPA-LFD assays, positive results first peaked at 4-5 dpi in the mice, and the positivity rate was 37.5% in the goats at 1 dpi. In conclusion, neither of the molecular methods produced exceptional results for the early diagnosis of S. japonicum infection. However, they were useful methods for the regular diagnosis of schistosomiasis in mice and goats.

Establishment of a reverse transcription real-time quantitative PCR method for Getah virus detection and its application for epidemiological investigation in Shandong, China.

Getah virus (GETV) is a mosquito-borne, single-stranded, positive-sense RNA virus belonging to the genus Alphavirus of the family Togaviridae. Natural infections of GETV have been identified in a variety of vertebrate species, with pathogenicity mainly in swine, horses, bovines, and foxes. The increasing spectrum of infection and the characteristic causing abortions in pregnant animals pose a serious threat to public health and the livestock economy. Therefore, there is an urgent need to establish a method that can be used for epidemiological investigation in multiple animals. In this study, a real-time reverse transcription fluorescent quantitative PCR (RT-qPCR) method combined with plaque assay was established for GETV with specific primers designed for the highly conserved region of GETV Nsp1 gene. The results showed that after optimizing the condition of RT-qPCR reaction, the minimum detection limit of the assay established in this study was 7.73 PFU/mL, and there was a good linear relationship between viral load and Cq value with a correlation coefficient (R2) of 0.998. Moreover, the method has good specificity, sensitivity, and repeatability. The established RT-qPCR is 100-fold more sensitive than the conventional RT-PCR. The best cutoff value for the method was determined to be 37.59 by receiver operating characteristic (ROC) curve analysis. The area under the curve (AUC) was 0.956. Meanwhile, we collected 2,847 serum specimens from swine, horses, bovines, sheep, and 17,080 mosquito specimens in Shandong Province in 2022. The positive detection rates by RT-qPCR were 1%, 1%, 0.2%, 0%, and 3%, respectively. In conclusion, the method was used for epidemiological investigation, which has extensive application prospects.

Detection of Pseudomonas aeruginosa Serogroup G Using Real-Time PCR for Novel Target Genes Identified Through Comparative Genomics.

Accurate serotyping is essential for effective infection control. Pseudomonas aeruginosa serogroup G is one of the most common serogroups found in water. Conventional serotyping methods are not standardized and have several shortcomings. Therefore, a robust method for rapidly identifying P. aeruginosa serotypes is required. This study established a real-time PCR method for identifying P. aeruginosa serogroup G strains using novel target gene primers based on comparative genomic analysis. A total of 343 genome sequences, including 16 P. aeruginosa serogroups and 67 other species, were analyzed. Target genes identified were amplified using real-time PCR for detecting P. aeruginosa serogroup G strains. Eight serogroup G genes, PA59_01276, PA59_01887, PA59_01888, PA59_01891, PA59_01894, PA59_04268, PA59_01892, and PA59_01896, were analyzed to determine specific targets. A real-time fluorescence quantitative PCR method, based on the novel target PA59_01276, was established to detect and identify serogroup G strains. The specificity of this method was confirmed using P. aeruginosa serogroups and non-P. aeruginosa species. The sensitivity of this real-time PCR method was 4 × 102 CFU/mL, and it could differentiate and detect P. aeruginosa serogroup G in the range of 4.0 × 103–4.0 × 108 CFU/mL in artificially contaminated drinking water samples without enrichment. The sensitivity of these detection limits was higher by 1–3 folds compared to that of the previously reported PCR methods. In addition, the G serum group was accurately detected using this real-time PCR method without interference by high concentrations of artificially contaminated serum groups F and D. These results indicate that this method has high sensitivity and accuracy and is promising for identifying and rapidly detecting P. aeruginosa serogroup G in water samples. Moreover, this research will contribute to the development of effective vaccines and therapies for infections caused by multidrug-resistant P. aeruginosa.

Visual detection of CaMV35S promoter via target-triggered rolling circle amplification of DNAzyme

The cauliflower mosaicvirus 35S (CaMV35S), as the most common promoter, has a usage rate of 70 % in transgenic crops, especially in dicots. Herein, a visual detection method of rolling circle amplification (RCA) combined with DNAzyme technology was developed for the determination of CaMV35S gene. A template sequence of the G-quadruple gene was designed for combining with the target gene CaMV35S. When the target gene existed, the RCA reaction occurred through the action of the enzyme, and the product combined with hemin to generate DNAzyme, which catalyzed the color reaction of 2′-hydrazine-bis-3-ethylbenzothiazolin-6-sulfonic acid (ABTS). Under the optimal experimental conditions, the linear range is 1 × 10−13∼1 × 10-8 mol/L, and the detection limit is 3 × 10-14 mol/L (S/N = 3). The method has been successfully applied to standard samples and practical samples (soybean and tofu). For verifying the feasibility and reliability, real-time fluorescent quantitative PCR method was used to detect the target gene CaMV35S, and the results were in good agreement with those of our method, indicating that our developed method can be used for the determination of actual samples.

Effect of moxibustion at "Zusanli" (ST 36) and "Shenshu" (BL 23) on intestinal flora in adjuvant arthritis rats

To observe the effect of moxibustion at "Zusanli" (ST 36) and "Shenshu" (BL 23) on inflammatory factors and intestinal flora in the rats with adjuvant arthritis. A total of 36 Wistar rats were randomized into a normal group, a model group and a moxibustion group, 12 rats in each one. In the model group and the moxibustion group, the adjuvant arthritis model was established by a compound method, including the environmental factors, i.e. wind, cold and damp, and Freund's complete adjuvant. In the moxibustion group, moxibustion intervention was exerted at "Zusanli" (ST 36) and "Shenshu" (BL 23), for 20 min at each acupoint, once daily, consecutively for 21 days. The paw swelling degree and arthritis index (AI) score were observed before and after intervention in the rats of each group. Using real-time fluorescence quantitative PCR method (real-time PCR) and Western blot method, the mRNA and protein expressions of inflammatory factors of colon tissue, i.e. interleukin (IL) 1β, tumor necrosis factor-α (TNF-α), IL-6, were detected after intervention in the rats of each group. The intestinal flora was detected with 16SrRNA sequencing technology after intervention in the rats of each group. Compared with the normal group, the paw swelling degree and AI score were increased in the rats of the model group (P<0.05); after intervention, compared with the model group, the paw swelling degree and AI score were reduced in the rats of the moxibustion group (P<0.05). Compared with the normal group, the expressions of IL-1β, TNF-α and IL-6 mRNA, as well as proteins were increased in the colon tissue of the rats in the model group (P<0.05); compared with the model group, the expressions of IL-1β, TNF-α and IL-6 mRNA, as well as proteins were reduced in the colon tissue of the rats in the moxibustion group (P<0.05). Compared with the normal group, OTUs count was reduced in the rats of the model group (P<0.05); and compared with the model group, OTUs count was increased in the rats of the moxibustion group (P<0.05). Compared with the normal group, Simpson index was increased, Chao1 and Ace were reduced in the rats of the model group (P<0.05); while, compared with the model group, Chao1 and Ace were increased in the rats of the moxibustion group (P<0.05). Compared with the normal group, the relative abundance of uncategorized Clostridium, Lactobacillus, Prevotella, uncategorized Porphyromonadaceae and uncategorized Prevotella was increased (P<0.05), and the relative abundance of uncategorized Spironella was reduced in the model group (P<0.05). While, compared with the model group, the relative abundance of uncategorized Clostridium, Lactobacillus, uncategorized Prevotella was reduced in the moxibustion group (P<0.05) and that of uncategorized Spironella was increased (P<0.05). Moxibustion at "Zusanli" (ST 36) and "Shenshu" (BL 23) relieves the joint symptoms of adjuvant arthritis rats and inhibits the expressions of inflammatory factors, which is probably related to the regulation of the structure of intestinal flora.

Preparation of DNA Origami Belt and Effect of pH on Its Stability

Abstract The long single-stranded DNA containing multiple copy units prepared by rolling circle amplification technique was used as a scaffold strand. The scaffold strands were hybridized to three short staple strands by molecular self-assembly and produced DNA origami belt. Using the principle of SYBR Green real-time fluorescence quantitative PCR method and atomic force microscopy (AFM) imaging technology, the formation of double-stranded structure was examined by the change of fluorescence signal intensity in the reaction solution while the morphology of DNA belts was observed by AFM intuitively. The effect of pH value on the stability of DNA belt was studied, and its performance of pH-resistant in the wide pH range of 3–11 was obtained. DNA belts exhibited the best stability in neutral pH enviroment (pH = 7), which showed a significantly higher fluorescence signal than that of other groups within 24 h. DNA belts had poor resistance to acid and alkali environment, especially to extreme pH conditions (pH = 3, pH = 11). At extreme pH, even instantaneous treatments (

A Universal Real-Time Fluorescence qPCR Method for Identifying Epidemic Strains of African Swine Fever Virus

Objective Establishing a highly sensitive real-time fluorescence quantitative PCR (qPCR) method for universal testing of epidemic African swine fever virus (ASFV) strains. Methods The ASFV p72 gene was targeted to design primer probes covering 24 p72 genotypes. The optimal amount of dimethylsulphoxide (DMSO) for qPCR amplification was determined, Various sensitivity and limit of detection (LOD) tests were performed, and clinical samples from China and imported goods were tested. Results The optimal primer-probe combination could specifically detect ASFV, 1.5% DMSO was optimal for qPCR, and LOD reached 3.2 copies/μL with good reproducibility (n = 20, p = 0.369). The method was employed to test 142 clinically suspected samples, of which 30 pig blood and 37 pig tissue samples were ASFV-positive. Moreover, the positive testing rate for ASFV was higher than for the standard qPCR method recommended by the Office International Des Epizooties (OIE), and for the commercially available kit. Thus, our method is superior for testing weakly positive samples with low virus titre, and epidemic strains present in imported goods. Conclusion Our method could be employed for universal testing of epidemic ASFV strains worldwide, ensuring wider coverage of hosts and ASFV strains/endemic strains, reducing false negatives, and benefitting early diagnosis.

Expression of CYP2E1 in different brain regions during the formation of toxic cerebral edema induced by 1, 2-DCE in mice and its effect on cerebral edema formation

Objective: To study the expression changes of cytochrome P-450 2E1 (CYP2E1) in different brain regions during 1, 2-dichloroethane (1, 2-DCE) exposure, and to explore the effect of CYP2E1 on the influence and effect of brain edema caused by 1, 2-DCE poisoning. Methods: In December 2018, forty female SPF Kunming mice were randomly divided into 4 groups: control group, 1 d, 2 d, and 3 d exposure groups, with 10 mice in each group. Placed in a 100 L static poisoning cabinet (5 animals/cabinet) , inhaled and exposed to the poison at 1.2 mg/L 1, 2-DCE for 3.5 h per day for 1 d, 2 d and 3 d. Except for exposure to 1, 2-DCE, other treatment methods were the same as those in the exposure groups. They were put to death the next day after the end of the poisoning, and the brain tissue was quickly removed and divided into sections. HE staining method was used for different brain regions. Western blotting method was used to detect the protein content of CYP2E1, occludin and claudin5 in different brain regions, real-time fluorescent quantitative PCR method was used to detect the mRNA expression levels of CYP2E1, occludin and claudin5. Histopathological observations were performed, and the kit method was used to detect malondialdehyde (MDA) , reduced glutathione (GSH) content and catalase (CAT) activity in different brain regions. The experimental data were analyzed by SPSS 20.0. One-way analysis of variance (one-way ANOVA) was used for the comparison of multiple groups, and the SNK (q test) method was used for the pairwise comparison between groups.P<0.05 was considered statistically significant. Results: Compared with the control group, histopathological observations showed obvious brain edema in the 2 d and 3 d exposure groups; Compared with the control group, the MDA content, CYP2E1 protein and mRNA expression levels in the cerebellar tissues of the mice in the 3 d exposure group were significantly increased, and the differences were statistically significant (P<0.05) ; Compared with the control group, the GSH content, CAT activity, occludin and claudin5 protein expression levels in the cerebellar tissues of the mice in each exposure group were significantly reduced, and the differences were statistically significant (P<0.05) . There was no significant difference in the above indicators of frontal cortex in each group in mice (P>0.05) . Conclusion: 1, 2-DCE can induce the expression of CYP2E1 in cerebellar tissues of mice, and cause oxidative damage and brain edema, but has no effect on the expression of CYP2E1 in frontal cortex of mice.

Study on lipid-lowering mechanism of active peptide DP17 from Eupolyphaga steleophaga in hyperlipidemia rats

The aim of this paper was to investigate the mechanism of the active peptide DP17 of Eupolyphaga steleophaga in the treatment of hyperlipidemia rats. HPLC and MADIL-TOF/TOF-MS were used for the amino acid sequence analysis and solid-phase synthesis on the active peptide of E. steleophaga which were obtained by biomimetic enzymatic hydrolysis, separation and purification. The hyperlipidemia model was established by feeding with high-fat diet.Twenty days later, the rats in the blank group and the model group were given the saline and the rats in remaining groups were given the corresponding drugs by oral administration. After administration for 4 weeks, the levels of triglyceride(TG), total cholesterol(TC) and low density lipoprotein(LDL) in serum, the levels of TG, TC, adenosine monophosphate(AMP), adenosine triphosphate(ATP) in liver tissues and TG in feces were detected, respectively. Hematoxylin-eosin(HE) staining was used to observe the pathological changes of liver tissues. The Real-time fluorescence quantitative PCR method was used to detect the expression of acetyl coa carboxylase(ACC) and hydroxymethylglutaryl-coa reductase(HMGCR) mRNA in liver tissues. The expression of mammalian target of rapamycin(mTORC1) protein and adenosine 5'-monophosphate-activated protein kinase(AMPK) in liver tissues were detected by Western blot. The analysis showed that the amino acid sequence of active peptide from E. steleophaga was DAVPGAGPAGCHPGAGP(DP17). The results of pharmacological experiments showed that after oral administration of DP17 in rats, the levels of TG, TC and LDL in serum as well as TG and TC levels in liver tissues were significantly decreased(P&lt;0.05), while the levels of AMP, ATP in liver tissues and TG content in feces were significantly increased(P&lt;0.05); the liver steatosis of rats was significantly relieved; the expression of ACC, HMGCR mRNA and mTORC1 protein in liver tissues were significantly reduced, while the expression of AMPK phosphorylated protein was significantly increased(P&lt;0.05). DP17, the active peptide of E. steleophag can significantly reduce lipid accumulation in liver tissues, and it may play a role in reducing blood lipids by regulating the energy metabolism balance in the body and activating AMPK/mTOR signaling pathway.

Detection and analysis of stacked-trait transgenic events in imported practical soybean

The stacked-trait transgenic crop is a novel transgenic crop obtained by traditional cross-breeding of single-trait transgenic crops. In this study, real-time fluorescent quantitative PCR method was used for detection and analysis of stacked-trait transgenic events in 7 batches of imported practical soybean samples. Eight transgenic soybean events (GTS40-3-2, DAS44406-6, A5547-127, MON89788, MON87708, A2704-12, MON87701 and FG72) were identified. Single-seed and multi-target detection were further applied. Fifteen practical soybean seeds were extracted randomly from each batch and the stacked-trait MON87708 × MON89788 event was detected in 6 batches of samples. Detection rates were 20%, 73.3%, 86.7%, 20%, 86.6% and 40% with relative estimation contents of 7.58%, 55.46%, 70.70%, 41.73%, 49.63% and 16.14%, respectively. This research provided reference and guidance criteria for detection and supervision of imported transgenic soybean events.

Development of a TaqMan Based Real-Time Fluorescent Quantitative PCR Assay for Detection of Porcine Cytomegalovirus in Semen.

This study described a TaqMan based real-time fluorescent quantitative PCR (qPCR) method to detect porcine cytomegalovirus (PCMV) infection, targeting the conserved region of the DNA polymerase (DPOL) gene. The standard curve showed a linear regression relationship with a coefficient of 0.999 and a slope of y = −3.249x + 38.958 corresponding to the amplification efficiency at 99.8%. The limit of the qPCR method was 51.9 copies/μl. The established qPCR method showed excellent specificity, with no cross-reaction observed with common porcine pathogens. The coefficient of variation for intra-assay and interassay variability ranged up to 1.51% and 2.24%, respectively. PCMV positive signals can be found in semen using this qPCR method, which suggested that we should pay more attention to PCMV contamination in semen in order to eliminate PCMV infection in artificial insemination and xenotransplantation.

Population Dynamics of Wolbachia in Laodelphax striatellus (Fallén) Under Successive Stress of Antibiotics.

Wolbachia are the most common symbionts in arthropods; antibiotic treatment for eliminating the symbionts from their host is necessary to investigate the functions. Tetracycline antibiotics are widely used to remove endosymbiont Wolbachia from insect hosts. However, very little has been known on the effects of tetracycline on population size of Wolbachia in small brown planthopper (SBPH), Laodelphax striatellus (Fallén), an important insect pest of rice in Asia. Here, we investigated the dynamics of Wolbachia population density in females and males of L. striatellus by real-time fluorescent quantitative PCR method. The Wolbachia density in females and males of L. striatellus all declined sharply after treatment with 2mg/mL tetracycline for one generation, and continued to decrease to a level which could not be detected by both qPCR and diagnostic PCR after treated for another generation, then maintained at 0 in the following three generations with continuous antibiotic treatment. Wolbachia infection did not recover in L. striatellus after stopping tetracycline treatment for ten generations. This is the first report to precisely monitor the population dynamics of Wolbachia in L. striatellus during successive tetracycline treatment and after that. The results provide a useful method for evaluating the efficiency of artificial operation of endosymbionts.

Complete Genome and Plasmid Sequences of Seven Isolates of Salmonella enterica subsp. enterica Harboring the mcr-1 Gene Obtained from Food in China.

Seven Salmonella enterica subsp. enterica isolates were identified as carrying the mcr-1 gene, by using a real-time fluorescence quantitative PCR method, from a total of 2,558 isolates which were cultured from various food origins in China between 2011 and 2016. Few complete genomes of Salmonella strains harboring the mcr-1 gene have been reported to date, so we report here the complete genome and plasmid sequences of all of these isolates to provide useful references for understanding the prevalence of foodborne Salmonella enterica subsp. enterica isolates carrying mcr-1.

A real-time fluorescence quantitative PCR method for source identification of Crocus sativus and Carthamus tinctorius

The specific PCR primer was designed base on ITS2 sequence in GenBank, and we developed a SYBRGreen real-time fluorescence quantitative PCR system for identification of Crocus sativus and Carthamus tinctorius source. Compared with Chinese herbal medicine DNA barcode technique, this method showed characteristics of shorter time, higher specificity and sensitivity. Using this method to detect 15 samples, 4 were C. sativus, 8 were C. tinctorius, and the other 3 samples were none of them. The result was in accordance with Chinese herbal medicine DNA barcode. This study lays the foundation for identification of related Chinese medical materials.

Protective effect of acupuncture preconditioning on oxidative stress injury induced by myocardial ischemia-reperfusion injury in rats

To observe the protective effect of acupuncture preconditioning at "Jiaji" (EX-B 2) on acute myocardial ischemia-reperfusion injury (MIRI) in the rats and explore the mechanism. Fifty Wistar rats were randomly divided into a control group, a model group, a Jiaji group, a Neiguan group and a Quchi group, 10 rats in each one. In the Jiaji group, the Neiguan group and the Quchi group, electroacupuncture was given for preconditioning at "Jiaji" T4~T5 (EX-B 2), "Neiguan" (PC 6) and "Quchi" (LI 11) for 7 days before modeling. In the control group and the model group, the regular feeding was given, without any acupuncture. At the end of acupuncture, except the control group, ligating the left anterior descending coronary artery (LAD) was adopted to duplicate MIRI models in the rest groups. Electrocardio-gram (ECG) was monitored and ST-segment shift was analyzed. HE staining method was adopted to observe the morphology of cardiac tissue in the rats of the groups. The transmission electron microscope was used to observe myocardial cell ultrastructure. WST-1 method was used to determine the activity of serum superoxide dismutase (SOD), TBA method was used to determine the content of serum malondialehyde (MDA) and the real-time fluorescent quantitative PCR method to determine the expressions of Nrf 2 in ischemic myocardial tissue and downstream HO-1 gene. Compared with the control group, after LAD ligation, ST-segment was elevated and depressed in ECG apparently after reperfusion in the rest groups (all P<0.05). The ST-segment elevation in the Jiaji group and the Neiguan group was less than that in the model group (both P<0.05). Compared with the model group, SOD activity was increased apparently in the Jiaji group and the Neiguan group (both P<0.05), and MDA content was reduced apparently (both P<0.05). The effects in the Jiaji group were better than those in the Neiguan group (both P<0.05). Pathologically, "Jiajia" (EX-B 2) and "Neiguan" (PC 6) all improved the morphology of cardiac tissue and cell ultrastructure. The effects in the Jiaji group were much more significant and the improvements in the Quchi group were not apparent. Compared with the control group, the expressions of Nrf 2 and HO-1 gene in myocardial tissue were down-regulated in the model group (both P<0.05). Those were up-regulated apparently in the Jiaji group and the Neiguan group as compared with the model group (P<0.05, P<0.01). The up-regulation times of the expressions of Nrf 2 and HO-1 gene in the Jiajia group were the highest in comparison. Acupuncture preconditioning at "Jiaji" (EX-B 2) has the protective effect on cardiac ischemia and reperfusion damage, which is probably relevant with the up-regulation of Nrf 2-ARE pathway expression, the activation of endogenous anti-oxidative pathway, the improvement of oxygen free radical scavenging capacity and the alleviation of lipid peroxide damage.

Expression of WT1 gene in acute leukemia and its significance

Objective To explore the relationship between WT1 and prognosis of patients with acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL), and to evaluate the possibility of WT1 as a potential marker for monitoring the minimal residual disease (MRD). Methods Bone marrow mononuclear cells from 58 patients with primary AML, 32 patients with primary ALL, 40 patients with AML-complete remission (CR), 28 patients with ALL-CR and 31 patients with trilineage hyperplasia (control group) were collected. Real-time fluorescent quantitative PCR method was used to detect the expression of WT1 in all patients. The expression threshold of WT1 in each group was established. WT1 copy number/ABL copy number ratio×100% denotes the relative expression level of WT1 gene. Results Median relative expression level of WT1 in the control patients was much lower than that in primary AML patients [0.026% (0-0.240%) vs. 20.880% (3.550%-48.500%), Z=-7.74, P 20.880%) was 60.7% (17/28), while the CR rate was 76.7% (23/30) in those with lower WT1 expression. WT1 expression was increased dramatically in recurrent AML patients. Relative expression level of WT1 was significantly higher in primary ALL patients [0.350% (0.021%-10.780%)] compared with that in the control group Z=-2.58, P<0.05. There was no significant difference in relative expression level of WT1 between ALL and ALL-CR patients [0.038% (0-2.800%), P=0.065]. Conclusion WT1 expression level in AML patients is relatively high, which could be used as an effective index of prognosis evaluation and MRD monitoring for AML patients, but not for ALL patients. Key words: Leukemia, acute; Gene, WT1; Polymerase chain reaction