Double-Tube Multiplex TaqMan Real-Time PCR for the Detection of Eight Animal-Derived Dairy Ingredients.

Milk and dairy products represent important sources of nutrition in our daily lives. The identification of species within dairy products holds importance for monitoring food adulteration and ensuring traceability. This study presented a method that integrated double-tube and duplex real-time polymerase chain reaction (PCR) with multiplex TaqMan probes to enable the high-throughput detection of animal-derived ingredients in milk and dairy products. The detection system utilized one pair of universal primers, two pairs of specific primers, and eight animal-derived specific probes for cow, buffalo, goat, sheep, camel, yak, horse, and donkey. These components were optimized within a double-tube and four-probe PCR multiplex system. The developed double-tube detection system could simultaneously identify the above eight targets with a detection limit of 10-0.1 pg/µL. Validation using simulated adulterated milk samples demonstrated a detection limit of 0.1%. The primary advantage of this method lies in the simplification of the multiplex quantitative real-time PCR (qPCR) system through the use of universal primers. This method provides an efficient approach for detecting ingredients in dairy products, providing powerful technical support for market supervision.

Species Identification of Caviar Based on Multiple DNA Barcoding.

This study aimed to explore the applicability of DNA barcoding for assessing the authenticity of caviar on the Chinese market. A set of universal COI primers and two sets of designed primers based on COI and D-loop genes were used to identify maternal species of samples from 21 batches of caviar. The results showed that the PCR products from three sets of primers had more than 98% similarity to the sequences in database. The COI gene could not distinguish sturgeons with closed genetic relationships, while D-loop gene could effectively improve the accuracy of DNA barcoding and was more suitable to the identification of interspecific sturgeon than the COI gene. The neighbor-joining dendrogram further confirmed the applicability and accuracy of COI and D-loop genes in identifying maternal relatives of caviar (Acipenser baerii/Acipenser gueldenstaedtii/Acipenser schrenckii/Huso dauricus/Huso huso). Despite the limitations of mitochondrial DNA in identifying hybrid sturgeon species, the presence of counterfeit caviar of non-sturgeon ingredients could be excluded. All the caviar samples were identified successfully as sturgeon species, but the mislabeling rate of species was 33.4%, indicating that there were illegal phenomena such as disorderly labeling, mislabeling, and adulteration on the market.

The Effect of Filial Piety and Cognitive Development on the Development of Adolescents' Depressive Symptoms: A Longitudinal Study.

The present study aims to investigate the pathways through which filial piety and cognitive development work on the development of depressive symptoms in adolescents as well as the trigger of adolescents' depressive symptoms (e.g., academic pressure). Two hundred fifty-seven Chinese adolescents (128 females and 129 males) participated in the study from Grade 7 to Grade 9. Results showed that both filial piety and cognitive autonomy significantly contribute to the development of adolescents' depressive symptoms and academic pressure. But reciprocal filial piety (RFP) and authoritarian filial piety (AFP) as two coexisting aspects of filial piety contribute to depressive symptoms in opposite directions. RFP provides significant protection against adolescents' depressive symptoms directly and indirectly through promoting the development of adolescents' cognitive autonomy and alleviating adolescents' academic pressure. In contrast, AFP positively contributes to adolescents' depressive symptoms by hindering the development of cognitive autonomy and intensifying academic pressure.

[Cytogenetic and molecular genetic analysis of small supernumerary marker chromosomes in fetal amniotic fluid].

OBJECTIVE: To explore the origin and mechanism of small supernumerary marker chromosomes (sSMC) in order to facilitate genetic counseling. METHODS: Chromosome karyotypes of two fetuses and their immediate family members were analyzed by conventional G banding. High-throughput whole genome sequencing was used to determine the origin of sSMCs. RESULTS: Fetus 1 was shown to have a karyotype of 47,XY,+mar but with normal FISH and B ultrasound findings. Its father also had a 47,XY,+mar karyotype with normal FISH results and clinical phenotype. High-throughput genome sequencing revealed that fetus 1 and its father were both 46,XY,dup(21)(q11.2;q21.1) with a 6.2 Mb duplication of the long arm of chromosome 21. The fetus was born with normal phenotype and developed well. Its grandmother also had a karyotype of 46,XX,t(15;21)(q13;p13) with normal FISH result and clinical phenotype. The karyotypes of its mother and grandfather were both normal. Analysis of fetus 2 showed a 47,XY,+mar karyotype with normal FISH results. High-throughput genome sequencing suggested a molecular karyotype of 46,XX. The fetus was born with normal phenotype and developed well. The karyotypes of its parents were both normal. CONCLUSION: Considering their variable origins, identification of sSMC should combine conventional G banding analyses with high-throughput whole genome sequencing for precise delineation of the chromosomes.

Diagnostic significance of soluble human leukocyte antigen-G for gastric cancer.

Human leukocyte antigen-G (HLA-G) is a novel tumor marker. Increased level of soluble HLA-G (sHLA-G) in various tumor types has been reported. However, the potential diagnostic value of sHLA-G with other tumor markers in gastric cancer (GC) diagnosis is yet to be explored. In this study, plasma level of sHLA-G was measured in 81 GC patients, 53 benign gastric disease patients and 77 normal controls by ELISA. The serum levels of alpha fetoprotein (AFP), carcinoembryonic antigen (CEA), cancer antigen 125 (CA125), cancer antigen 19-9 (CA19-9) and cancer antigen 72-4 (CA72-4) were also determined. Data showed that plasma level of sHLA-G in GC was dramatically increased compared with normal controls and benign gastric disease patients (both p<0.001). The AUC for sHLA-G was 0.730 (p<0.001), superior to serum AFP, CEA, CA125, CA19-9 and CA72-4. After evaluating three cut-offs of sHLA-G, we concluded sHLA-G (cut-off at 128U/ml) plus CA125 in two-biomarker panel test and CA125 plus CA199 plus sHLA-G or CA125 plus CA724 plus sHLA-G in three-biomarker panel test were better choices for GC discrimination. Our findings indicated that sHLA-G was a potential biomarker for GC diagnosis and the combination of sHLA-G with CA125, CA19-9 and CA72-4 can improve the clinical screening and diagnosis for GC.

[Genetic analysis and counseling for two fetal cases with large de novo Yq deletions].

OBJECTIVE: To analyze the deletion region for two fetal cases with large Yq deletions in order to provide genetic counseling and prenatal diagnosis. METHODS: For both cases, amniotic fluid samples were cultured and analyzed with G banding and fluorescence in situ hybridization (FISH). Multiplex polymerase chain reaction was also carried out to amplify 15 sequence tagged sites (STS) of azoospermia factor (AZF) on the Y chromosome. RESULTS: For both samples, the karyotypes were determined as 46,X,del(Y)(pter→q11:). No heterochromatin was found in C band. The karyotypes of their fathers were 46,XY, and heterochromatin was found in C band. STS analyses suggested that only sY82, sY84 and sY86 in AZFa were amplifiable while the other 12 STS were negative in amniotic fluid for the first case, which indicated deletions of AZFb, AZFd and AZFc. No AZF deletion was found in its father. For the second case, all 15 STS were amplifiable in the amniotic fluid, suggesting no AZF deletion. No AZF deletion was found in its father too. CONCLUSION: Conventional karyotyping combined with FISH and molecular genetics techniques can enable characterization of AZF microdeletions and facilitate genetic counseling and prenatal diagnosis.

[Analysis of two false positive cases from noninvasive prenatal testing].

OBJECTIVE: To track and analyze two false positive cases from non-invasive prenatal testing for potential fetal aneuploidy. METHODS: The two cases, respectively reported to have XO (+++) and T18 (1/20) XO(+), were analyzed with conventional karyotyping, fluorescence in situ hybridization (FISH) and massively parallel genomic sequencing (MPS). RESULTS: The first fetus, who was suspected for XO(+++), was verified to have super female syndrome (47,XXX/46,XX) due to confined placental mosaicism by karyotyping of amniotic fluid cells, FISH analysis of placenta and massively parallel sequencing (MPS) of fetal tissue. The second fetus, suspected to have trisomy 18 (1/20) XO(+), was verified to have Turner syndrome by karyotyping, FISH and MPS analyses of umbilical cord blood cells. And the karyotype was 45,X[48]/46, X, der(X) del(X) (p11.21) del(X) (q13.3)[62]. CONCLUSION: Non-invasive prenatal testing carries a risk for false positive diagnosis of fetal sex chromosome and trisomy 18. Combined cytogenetic and molecular techniques are required to ensure an accurate diagnosis.

Associations between epidermal growth factor receptor gene mutation and serum tumor markers in advanced lung adenocarcinomas: a retrospective study.

OBJECTIVE: To investigate the associations between epidermal growth factor receptor (EGFR) gene mutations and serum tumor markers in advanced lung adenocarcinomas. METHODS: We investigated the association between EGFR gene mutations and clinical features, including serum tumor marker levels, in 97 advanced lung adenocarcinomas patients who did not undergo the treatment of EGFR tyrosine kinase inhibitors. EGFR gene mutation was detected by real-time PCR at exons 18, 19, 20, and 21. Serum tumor marker concentrations were analyzed by chemiluminescence assay kit at the same time. RESULTS: EGFR gene mutations were detected in 42 (43%) advanced lung adenocarcinoma patients. Gender (P=0.003), smoking status (P=0.001), and abnormal serum status of carcinoembryonic antigen (CEA, P=0.028) were significantly associated with EGFR gene mutation incidence. Multivariate analysis showed the abnormal CEA level in serum was independently associated with the incidence of EGFR gene mutation (P=0.046) with an odds ratio of 2.613 (95% CI: 1.018-6.710). However, receiver operating characteristic (ROC) curve analysis revealed CEA was not an ideal predictive marker for EGFR gene mutation status in advanced lung adenocarcinoma (the area under the ROC curve was 0.608, P=0.069). CONCLUSIONS: EGFR gene mutation status is significantly associated with serum CEA status in advanced lung adenocarcinmoas. However, serum CEA is not an ideal predictor for EGFR mutation.

[Gel immobilization of human genome].

OBJECTIVE: To develop a solid phase PCR method by covalent single point immobilization for recycle utilization of human genome. METHODS: Polymethacrylamide gel was selected as a solid PCR carrier based on DNA-hydrogel copolymer chemistry presented by Mirzabekov. (CH2)6NH2 amino-modified PCR product and randomly fractured formic acid-modified plasmid pGEM-T-HLA-G were used as templates. The specificity of the attachment chemistry was characterized by acrylamide gel electrophoresis, and the thermal stability of method was demonstrated by PCR. This method was applied for the recycle utilization of human genome. Sequencing was used to exclude the possibility of introduced mutations during modification and immobilization procedures. RESULTS: The PCR detections of plasmid DNA and human genome DNA immobilized by polymethacrylamide gel was successful. The thermal stability of method was successfully demonstrated by performing PCR after 16 rounds of standard 36 PCR cycles. And the sequencing was found no mutation. CONCLUSION: The DNA immobilization method with polymethacrylamide gel as a solid phase carrier is stable and specific, which can be a possible approach for realizing recycle utilization of human genome for whole-genome sequencing and SNP detection.

[Whole-genome sequencing: a new approach for understanding of pathogenesis and individualized treatment of cancer].

With the development of sequencing technology, the cost of whole-genome sequencing was significantly declined.Meanwhile, with the application of combined whole-genome sequencing with epigenetic analysis on methylation and histone acetylation, the comprehensive and systematic analysis of numerous samples became a reality and we are able to re-understand the genesis and development of cancer. New ideas are emerging in comparative genomics research methods, from comparison of genomes among different individuals to horizontal self-comparison of different tissues and vertical self-comparison of genomes recently.Individualized diagnosis and treatment of cancer has shown a bright future.

[Effect of rapamycin on apoptosis in human myelodysplastic syndrome cell line MUTZ-1 and its possible mechanisms].

The aim of this study was to investigate the effect of rapamycin on cell growth and apoptosis in the myelodysplastic syndrome (MDS) cell line MUTZ-1 and possible mechanism. MUTZ-1 cells were treated with rapamycin, cell proliferation capability was determined with MTT, protein expression including Annexin V/PI, caspase 3, PTEN, p-Akt, p-mTOR and the cell cycle were analyzed with flow cytometry. The results indicated that the proliferation of MUTZ-1 cells was inhibited by rapamycin in concentration-and time-dependent manners (r=0.67, 0.61, 0.72). After treatment with rapamycin for 24-72 hours, cell count in G0/G1 were significantly higher than that of the control (p<0.01), and this effect showed a time-and concentration-dependency (r=0.94, 0.93, 0.92), the cell cycle was blocked in G0/G1 phase. As compared with control group, the proportion of Annexin V+PI-MUTZ-1 cells and the cellular PTEN levels increased in the treated group dramatically and in time-and dose-dependent manners (p<0.01). To the contrary, level of p-mTOR expression markedly decreased as compared with control group (p<0.05). It is concluded that the rapamycin inhibits the proliferation of MUTZ-1 cells, down-regulates the PTEN/PI3K-Akt/mTOR signaling pathway by interaction with mTOR, which induces the apoptosis of mUTZ-1 cells.

Identification of protein components and quantitative immunoassay for SEC2 in staphylococcin injection.

In China, staphylococcin injection has been commonly used in combined cancer therapy to enhance the systemic immune response and reduce the toxicities associated with chemotherapy or radiation therapy in the last decade. It is claimed that the main effective component is staphylococcal enterotoxin C2 (SEC2). However, no standard method based on the concentration of SEC2 has been established for quality control of the injection products. In this study, a sensitive and reliable biotin-streptavidin-ELISA (BS-ELISA) method was established for detection and quantification of SEC2. In addition, 1-D SDS-PAGE coupled with nano-LC-MS/MS was performed to identify the protein components in the injection products from one manufacturing company. The results of the BS-ELISA showed that SEC2 only accounted for less than 0.1% of the total protein in the injection products, and the nano-LC-MS/MS results showed that fifty-five proteins of Staphylococcus aureus were confidently identified in the injection solution. Seventeen out of these proteins, including SEC2, were well-known virulence factors. In addition, eighteen proteins of other Gram-positive bacteria were also confidently identified. Thus, the results indicated that SEC2 is of very low concentration in the injection products and the process of the injection preparation should be improved for health and safety consideration.

[Preparation and application of antibody against staphylococcal enterotoxin C2].

The filtrate of Staphylococcus aureus culture has been used in an ampule form named as staphylococcal enterotoxin C injection for cancer therapy in clinic for ten years in China and proved to be effective. The active constituent of three kinds of injections is claimed to be staphylococcal enterotoxin C2 (SEC2), and the content of SEC2 is used as quality control. However, the correct content of SEC2 was not known and the relative amount of SEC2 was very low because of the complicated components of the filtrate. In this research, we established a proper ELISA system for the detection of SEC2 in staphylococcal enterotoxin C injection, which will improve the quality control of the injection. We produced and identified polyclonal and monoclonal antibodies of SEC2 and established BA-ELISA method based on the method of sandwich ELISA. It was found that the BA-ELISA method had good specificity, sensitivity and reproducibility, and being able to detect SEC2 at concentration from 2 to 20 ng x mL(-1), with an average CV value of 5.08%. The SEC2 content in staphylococcal enterotoxin C injection was calculated. There is some difference between the actual and labeled contents in the injections.

[Expression and bioactivity of the cloned staphylococcal enterotoxin O].

This study is to clone the gene of staphylococcal enterotoxins O, obtain recombinant protein (rSEO) and investigate its activity on mice lymphocyte. Staphylococcus aureus O gene is cloned into GST gene fusion vector pGEX-4T-1. The resultant plasmid pGEX-4T-SEO was used to transform E. coLi BL21, where the GST-SEO fusion protein was expressed efficiently. Then SEO was purified by Glutathione Sepharose 4B affinity column and digested with thrombin. The bioactivity of SEO was analyzed by MTT assay on mice lymphocyte and tumor cells. The nucleotide sequence was confirmed to code for the protein correctly, and soluble SEO was expressed efficiently in E. coli BL21 with pGEX-4T-SEO. The protein purified by affinity chromatography resulted to be one single band by SDS-PAGE detection. The MTT assay of the purified rSEO demonstrated that its abilities of stimulating T cells and inhibiting the proliferation of K562, K562-ADM and B16 cells were equivalent to that of SEC in vitro. The expression plasmid pGEX-4T-SEO was constructed and the recombinant superantigen was expressed successfully, which may provide a foundation for the further research of the anticancer activity of SEO.

Expression and bioactivity analysis of Staphylococcal enterotoxin M and N.

Staphylococcal enterotoxins (SEs) are powerful superantigens that stimulate non-specific T-cell proliferation produced by Staphylococcus aureus and draw considerable attention as ideal drugs for cancer therapy. The filtrate of S. aureus culture has been used as ampul named Staphylococcal enterotoxin C injection in clinic for 10 years in China and proved to be effective. The superantigen SEC claimed to be the only active component without certifiable evidences. For further investigations of the active components of this injection and establishment of foundations for the development of novel anti-cancer drugs, in this research we extracted total DNA from S. aureus (FRI 1230), cloned, expressed and purified recombinant proteins of Staphylococcal enterotoxin M and N (rSEM and rSEN). The MTT assay of the purified rSEM and rSEN demonstrated that their abilities of stimulating T cells and inhibiting the proliferation of K562-ADM cells and B16 cells were equivalent to that of purified SEC2 in vitro. These findings suggested that SEC was not the only active component of Staphylococcal enterotoxin C injection and the effective procedure of expression and purification may be useful for mass productions of these therapeutically important proteins.

[Expression and bioactivity analysis of staphylococcal enterotoxin C2].

AIM: To clone the gene of staphylococcal enterotoxin C2 and express it in the form of a soluble fusion protein in E. coli. Then the activation of SEC2 on mice lymphocyte and its lethal effects on tumor cells were studied. METHODS: Staphylococcus aureus SEC2 gene was cloned into GST gene fusion vector pGEX-4T-1. The resultant plasmid pGEX-4T-SEC2 was used to transform E. coli BL21, where the GST-SEC2 fusion protein was expressed efficiently. The rSEC2 protein was purified with Glutathione Sepharose 4B affinity column and digested with thrombin. The in vitro culture system was utilized to observe the activation of the SEC2 on mice lymphocyte and the lethal effects on tumor cells of the activated mice lymphocyte. RESULTS: The proper gene of SEC2 was cloned and purified rSEC2 was obtained. The MTT results indicated that rSEC2 have strong ability to stimulate mice lymphocyte to proliferate with a dose-dependent manner. With the proliferation of mice splenic lymphocyte, rSEC2 has a strong lethal effect on tumor cells B16, K562 and K562-AD. CONCLUSION: In this study, the gene of SEC2 was cloned and the rSEC2 protein was obtained, which had strong lethal effect on tumor cells B16, K562 and K562-AD.