Genotypes of Bordetella pertussis isolated from infants in Xi'an and Shanghai.

OBJECTIVE: To compare the genotypes of Bordetella pertussis isolated from infants in Xi'an and Shanghai. METHODS: Samples were collected by nasopharyngeal swab from infants aged <1 year hospitalized with suspected pertussis in Xi'an and Shanghai during 2018 and 2019. Bordetella pertussis was isolated, and multilocus antigen sequence typing (MAST) and multilocus variable-number tandem repeat analysis (MLVA) were used to analyse the genotypes. RESULTS: A total of 1200 samples were collected from infants suspected of pertussis and 60 strains of Bordetella pertussis were isolated, including 34 strains in Xi'an and 26 strains in Shanghai. There were significant differences in the MAST types between Xi'an and Shanghai ( χ 2=18.642, P<0.01); the prn1/ ptxP1/ ptxA1/ fim3-1/ fim2-1 strains dominated in Xi'an (32/34, 94.12%), while the dominated MAST types in Shanghai were prn1/ ptxP1/ ptxA1/ fim3-1/ fim2-1 (13/26, 50.00%) and prn2/ ptxP3/ ptxA1/ fim3-1/ fim2-1 (11/26, 42.31%). The composition of MLVA type of pertussis strains was also significantly different between Xi'an and Shanghai ( χ 2=15.866, P<0.01); the MT195 (13/34, 38.24%), MT55 (10/34, 29.41%) and MT104 (9/34, 26.47%) strains dominated in Xi'an, while the MT27 (12/26, 46.15%) strain was most common in Shanghai. CONCLUSION: There are differences in molecular types of Bordetella pertussis isolated from infants with suspected persussis in Xi'an and Shanghai, indicating that further monitoring of Bordetella pertussis is necessary for better understanding the pathogen evolution in China.

RETRACTED ARTICLE: Ultrasound microbubble-mediated miR-150-5p inhibits gastric cancer cell growth by targeting the expression of NR2F2.

We, the Editor and Publisher of the Journal of Receptors and Signal Transduction, have retracted the following article: Ultrasound microbubble-mediated miR-150-5p inhibits gastric cancer cell growth by targeting the expression of NR2F2; Wei Wei, Xiaoguang Wei, Minyu Zhang & Cheng Peng; https://doi/10.1080/10799893.2021.1884260Since publication, concerns have been raised about the integrity of the following figures in the article. 2(A) miR-NC and 2(D) miR-NC-MBs;2(A) Control and 5(C) NR2F2-MBs + miR-NC-MBsWhen approached for an explanation, the authors were unable to provide original data in a suitable format that would confirm the authenticity of the data. The authors have been notified of the retraction but have not responded.We have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines on retractions.The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as 'Retracted'.

Influence of Different Inactivation Methods on Severe Acute Respiratory Syndrome Coronavirus 2 RNA Copy Number.

The outbreak of coronavirus disease 2019 (COVID-19) has spread across the world and was characterized as a pandemic. To protect medical laboratory personnel from infection, most laboratories inactivate the virus causing COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in clinical samples before testing. However, the effect of inactivation on the detection results remains unknown. Here, we used a digital PCR assay to determine the absolute SARS-CoV-2 RNA copy number in 63 nasopharyngeal swab samples and assess the effect of inactivation methods on viral RNA copy number. Viral inactivation was performed by three different methods: (i) incubation with the TRIzol LS reagent for 10 min at room temperature, (ii) heating in a water bath at 56°C for 30 min, and (iii) high-temperature treatment, including autoclaving at 121°C for 20 min, boiling at 100°C for 20 min, and heating at 80°C for 20 min. Compared to the amount of RNA in the original sample, TRIzol treatment destroyed 47.54% of the nucleocapsid protein (N) gene and 39.85% of open reading frame (ORF) 1ab. For samples treated at 56°C for 30 min, the copy number of the N gene and ORF 1ab was reduced by 48.55% and 56.40%, respectively. The viral RNA copy number dropped by 50 to 66% after heating at 80°C for 20 min. Nearly no viral RNA was detected after autoclaving at 121°C or boiling at 100°C for 20 min. These results indicate that inactivation reduced the quantity of detectable viral RNA and may cause false-negative results, especially in weakly positive cases. Thus, use of the TRIzol reagent rather than heat inactivation is recommended for sample inactivation, as the TRIzol reagent had the least effect on the RNA copy number among the tested methods.

Hypoxia-induced proliferation in mesenchymal stem cells and angiotensin II-mediated PI3K/AKT pathway.

Hypoxia could stimulate proliferation of mesenchymal stem cells (MSCs) under certain conditions. This study determined angiotensin II mechanisms and PI3K/AKT pathway in hypoxia-induced proliferation of MSCs. Hypoxia (3% oxygen) induced cellular proliferation in mouse MSCs and upregulated endogenous angiotensin II and angiotensin-converting enzyme in the cell culture and expression of AT1 receptors. The expressions of Sox2, not Oct4 and Rex1, were significantly increased by the hypoxia. The blockade of AT1 receptors, not AT2 receptors, depressed hypoxia induced the proliferative effects. Both hypoxia and exogenous angiotensin II activated p-AKT. Moreover, AT1 receptor inhibitor blocked the effects of hypoxia-mediated p-AKT upregulation. The data demonstrated that the hypoxia at 3% oxygen level could induce mouse MSC proliferation, probably as a result of the activation of PI3K signalling pathways via AT1 receptors.

Macrolide susceptibility and molecular characteristics of Bordetella pertussis.

OBJECTIVE: To analyse macrolide resistance and molecular characteristics of Bordetella pertussis clinical isolates from western China, and to explore the relationship between macrolide-resistance and genotypes. METHODS: Susceptibilities of B. pertussis clinical isolates to erythromycin, azithromycin and clarithromycin were determined by epsilometer test (E-test). Isolated strains were sequenced to ascertain the presence of the 23S rRNA gene A2047G mutation. Strains were typed using multilocus antigen sequence typing, multilocus variable-number tandem-repeat analysis (MLVA) and pulsed-field gel electrophoresis (PFGE). RESULTS: Of 58 B. pertussis strains isolated in this study, 46 were macrolide-resistant and 12 were macrolide sensitive. All macrolide-resistant strains carried the A2047G mutation and were the prn1/ptxP1/ptxA1/fim3-1/fim2-1 genotype; the MLVA types were MT195 (19/58), MT55 (13/58) and MT104 (14/58), and the PFGE profiles were classified into BpSR23 (17/58) and BpFINR9 (29/58) types. None of the macrolide-sensitive strains carried the A2047G mutation; genotypes were (prn9 or prn2)/ptxP3/ptxA1/fim3-1/fim2-1, and all were MT27. PFGE profiles differed from the macrolide-resistant strains. CONCLUSIONS: B. pertussis clinical isolates from western China were severely resistant to macrolides. Genotypes differed between macrolide-resistant and macrolide-sensitive strains, and there may be a correlation between acquisition of macrolide resistance and changes in specific molecular types.

Development of a gold nanoparticle-based universal oligonucleotide microarray for multiplex and low-cost detection of foodborne pathogens.

Bacterial foodborne diseases remain major threats to food safety and public health, especially in developing countries. In this study a novel assay, combining gold nanoparticle (GNP)-based multiplex oligonucleotide ligation-PCR and universal oligonucleotide microarray technology, was developed for inexpensive, specific, sensitive, and multiplex detection of eight common foodborne pathogens, including Shigella spp., Campylobacter jejuni, Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica, Staphylococcus aureus, and Vibrio parahaemolyticus. The target fragments of the eight pathogens were enriched by multiplex PCR and subjected to multiplex ligase detection reaction. Ligation products were enriched and labeled with GNPs by universal asymmetric PCR, using excess GNP-conjugated primers. The labeled single-stranded amplicons containing complementary tag sequences were captured by the corresponding tag sequences immobilized on microarrays, followed by silver staining for signal enhancement. Black images of microarray spots were visualized by naked eyes or scanned on a simple flatbed scanner, and quantified. The results indicated that this assay could unambiguously discriminate all eight pathogens in single and multiple infections, with detection sensitivity of 3.3-85CFU/mL for pure cultures. Microarray results of ninety-five artificially contaminated and retail food samples were consistent with traditional culture, biochemical and real-time PCR findings. Therefore, the novel assay has the potential to be used for routine detection due to rapidity, low cost, and high specificity and sensitivity.

Research on ultra-fast vacuum mechanical switch driven by repulsive force actuator.

In order to meet the fast operation demands of DC circuit breakers, a high-speed vacuum mechanical switch (VMS) driven by a repulsive force actuator is focused. To improve the drive speed and energy conversion efficiency (ECE) of the actuators, the dynamic characteristics of the double sided coil repulsive force actuators are investigated, and two generalized optimization design methods focusing on the aspect ratio of the driving coils (defined as ARF) and the electrical parameters (defined as EF) are developed. FEM simulation models' simulation and tests of VMS prototypes are conducted to verify the optimization methods. Results prove that the ARF method could improve the ECE of a VMS from 1.05% to 7.55%, and EF method could improve ECE of the same VMS from 1.05% to 6.61%, the combination of ARF and EF could improve the value of VMS's ECE to 10.50%, thus proving the validity and accuracy of the optimization methods.

HPV16E7-specific siRNA inhibits cell proliferation in CaSki cells.

High-risk human papilloma virus (HPV) infection is the main cause for the genesis of cervical carcinomas. After infection, E6 and E7 genes of HPV were integrated to the genome of the cervical epithelium. Continued expression of the transforming oncoproteins E6 and E7 not only drives the neoplastic progression in cervical epithelium, but also plays an important role in maintaining the malignant phenotype of cervical cancer cells. The aim of this study is to explore the effects of liposomal transfection of HPV16E7 siRNA on the proliferation of cervical carcinoma cell line CaSki. The siRNA interfering HPV16E7 gene was synthesized and transfected into CaSki cells by liposome to observe the cell morphology changes under microscope. The cell proliferation index was detected by flow cytometry; HPV16E7 mRNA expression was determined by RT-PCR and its protein level was determined by Western blot. After transfection of the CaSki cell by siRNA, cell proliferation was inhibited significantly, and the expression of HPV16E7 mRNA and protein level of HPV16E7 decreased. HPV16E7 siRNA is able to inhibit growth of CaSki cells. HPV16E7 might become a new target for genetic therapy of cervical carcinoma.

Prenatal exposure to hypoxia induced Beclin 1 signaling-mediated renal autophagy and altered renal development in rat fetuses.

AIMS: Hypoxia has adverse effects on renal development. This study was the first to test hypoxia-induced renal autophagy in rat fetuses. METHODS: Pregnant rats were exposed to hypoxia or normoxia during pregnancy and fetal kidneys were collected at gestation day 21. RESULTS: Fetal kidney weight and ratio of kidney-body weight were reduced. Histological analysis showed enlargement in Bowman space and wider space between interstitia in the kidneys of fetus exposed to hypoxia. Fetal renal B-cell lymphoma 2 (BCL-2) was decreased accompanied with higher 2'-deoxyuridine 5'-triphosphate nick end-labeling staining and unchanged soluble FAS in the hypoxia group. Hypoxia increased autophagic structures, including autophagosomes and autolysosomes, in fetal kidneys and increased renal APG5L. There was an increase in renal LC3-II, Beclin 1, p-S6, hypoxia inducible factor 1α (HIF-1a), and ratio of LC3-II-LC3-I and a decrease in P62, protein kinase B (AKT), and phosphorylated AKT in the hypoxia group. Both renal mammalian target of rapamycin (mTOR) and Beclin 1 signaling were upregulated. CONCLUSION: Hypoxia-affected fetal renal development was associated with renal apoptosis and Beclin 1 signaling-mediated autophagy.

Hippocampal apoptosis involved in learning deficits in the offspring exposed to maternal high sucrose diets.

The hippocampus plays a crucial role in learning and memory, and neuronal apoptosis in the hippocampus contributes to learning deficits. Metabolism problems in pregnancy related to excessive fuel consumption (e.g., high fat, high sugar) may influence cognitive and behavioral functions in the offspring by affecting developing brain cells. This study determined the influence of maternal high sucrose (HS) diets on behavior and hippocampal neurons in the young offspring. The ratio of brain weight to body weight in the offspring exposed to prenatal HS diets was significantly decreased; the Morris water maze showed that the offspring exposed to prenatal HS diets exhibited increased escape latencies and path length during navigation testing, while there were no changes in time spent in the target quadrant and number of target approaches. In the offspring exposed to prenatal HS, TUNEL-positive cells were significantly increased in CA1, CA2 and CA3 of the hippocampus; protein expression of insulin-like growth factor-I, PI3K and phosphorylated Akt was significantly decreased, while caspase-3 and N-methyl-d-aspartate receptors were significantly increased in the hippocampus, and there was no change in expression of Bcl-2 and Akt. The results demonstrated that prenatal HS diets could induce the spatial acquisition deficits in the young offspring associated with hippocampal apoptosis, and altered signaling factors for antiapoptosis in the hippocampus might play a critical role in cognition disorders in young children.