Essential role of Alix in regulating cardiomyocyte exosome biogenesis under physiological and stress conditions.

BACKGROUND: Exosomes released by cardiomyocytes are essential mediators of intercellular communications within the heart, and various exosomal proteins and miRNAs are associated with cardiovascular diseases. However, whether the endosomal sorting complex required for transport (ESCRT) and its key component Alix is required for exosome biogenesis within cardiomyocyte remains poorly understood. METHODS: Super-resolution imaging was performed to investigate the subcellular location of Alix and multivesicular body (MVB) in primary cardiomyocytes. Cardiomyocyte-specific Alix-knockout mice were generated using AAV9/CRISPR/Cas9-mediated in vivo gene editing. A stable Alix-knockdown H9c2 cardiomyocyte line was constructed through lentiviral-mediated delivery of short hairpin RNA. In order to determine the role of Alix in controlling exosome biogenesis, exosomes from cardiomyocyte-specific Alix-knockout mice plasma and Alix-knockdown H9c2 culture medium were isolated and examined by western blot, NTA analysis and transmission electron microscopy. Biochemical and immunofluorescence analysis were performed to determine the role of ESCRT machinery in regulating MVB formation. Lastly, transverse aortic constriction (TAC)-induced cardiac pressure overload model was established to further explore the role of Alix-mediated exosome biogenesis under stress conditions. RESULTS: A significant proportion of Alix localized to the MVB membrane within cardiomyocytes. Genetic deletion of Alix in murine heart resulted in a reduction of plasma exosome content without affecting cardiac structure or contractile function. Consistently, the downregulation of Alix in H9c2 cardiomyocyte line also suppressed the biogenesis of exosomes. We found the defective ESCRT machinery and suppressed MVB formation upon Alix depletion caused compromised exosome biogenesis. Remarkably, TAC-induced cardiac pressure overload led to increased Alix, MVB levels, and elevated plasma exosome content, which could be totally abolished by Alix deletion. CONCLUSION: These results establish Alix as an essential and stress-sensitive regulator of cardiac exosome biogenesis and the findings may yield valuable therapeutic implications.

Fault Diagnosis of Rolling Bearing Based on HPSO Algorithm Optimized CNN-LSTM Neural Network.

The quality of rolling bearings is vital for the working state and rotation accuracy of the shaft. Timely and accurately acquiring bearing status and early fault diagnosis can effectively prevent losses, making it highly practical. To improve the accuracy of bearing fault diagnosis, this paper proposes a CNN-LSTM bearing fault diagnosis model optimized by hybrid particle swarm optimization (HPSO). The HPSO algorithm has a strong global optimization ability and can effectively solve nonlinear and multivariate optimization problems. It is used to optimize and match the parameters of the CNN-LSTM model and dynamically find the optimal value of the parameters. This model overcomes the problem that the parameters of the CNN-LSTM model depend on empirical settings and cannot be adjusted dynamically. This model is used for bearing fault diagnosis, and the accuracy rate of fault diagnosis classification reaches 99.2%. Compared with the traditional CNN, LSTM, and CNN-LSTM models, the accuracy rates are increased by 6.6%, 9.2%, and 5%, respectively. At the same time, comparing the models with different optimization parameters shows that the model proposed in this paper has the highest accuracy. The experimental results verified the superiority of the HPSO algorithm to optimize model parameters and the feasibility and accuracy of the HPSO-CNN-LSTM model for bearing fault diagnosis.

Molecular characteristics of norovirus in sporadic and outbreak cases of acute gastroenteritis and in sewage in Sichuan, China.

BACKGROUND: Norovirus is highly diverse and constant surveillance is essential for the prevention and control of norovirus gastroenteritis. METHODS: From 2015 to 2019, fecal samples were collected from sporadic cases and outbreaks of acute gastroenteritis reported to Sichuan center for disease control and prevention. Sewage samples were collected from a wastewater treatment plant in Sichuan. All samples were tested for norovirus by real-time reverse transcription polymerase chain reaction. Norovirus-positive clinical samples were sequenced by Sanger sequencing. Sewage samples were sequenced by amplicon and virome sequencing. RESULTS: A total of 1462 fecal samples were collected and 11 different norovirus genotypes were detected. GII.4 Sydney 2012[P31] and GII.3[P12] were the dominant genotypes in sporadic cases whereas GII.2[P16] and GII.17[P17] were the dominant genotypes in outbreaks. GII.3 was predominant in children 0-6 months of age during spring and summer, while GII.4 was predominant in children older than 6 months and in the autumn. The detection rate of GII.17[P17] increased with age. In sewage, 16 genotypes were detected. GII.3, GII.4, GI.1, and GI.2 were the dominant genotypes. CONCLUSION: This study demonstrated that multiple norovirus genotypes co-circulate in Sichuan. It is vital to continuously trace the genetic diversity of norovirus to give a future perspective on surveillance needs and guide vaccine design and policy decisions.

Microfluidic Chip with Two-Stage Isothermal Amplification Method for Highly Sensitive Parallel Detection of SARS-CoV-2 and Measles Virus.

A two-stage isothermal amplification method, which consists of a first-stage basic recombinase polymerase amplification (RPA) and a second-stage fluorescence loop-mediated isothermal amplification (LAMP), as well as a microfluidic-chip-based portable system, were developed in this study; these enabled parallel detection of multiplex targets in real time in around one hour, with high sensitivity and specificity, without cross-contamination. The consumption of the sample and the reagent was 2.1 µL and 10.6 µL per reaction for RPA and LAMP, respectively. The lowest detection limit (LOD) was about 10 copies. The clinical amplification of about 40 nasopharyngeal swab samples, containing 17 SARS-CoV-2 (severe acute respiratory syndrome coronavirus) and 23 measles viruses (MV), were parallel tested by using the microfluidic chip. Both clinical specificity and sensitivity were 100% for MV, and the clinical specificity and sensitivity were 94.12% and 95.83% for SARS-CoV-2, respectively. This two-stage isothermal amplification method based on the microfluidic chip format offers a convenient, clinically parallel molecular diagnostic method, which can identify different nucleic acid samples simultaneously and in a timely manner, and with a low cost of the reaction reagent. It is especially suitable for resource-limited areas and point-of-care testing (POCT).

Beware of pharyngeal Fusobacterium nucleatum in COVID-19.

BACKGROUND: Fusobacterium nucleatum (F. n) is an important opportunistic pathogen causing oral and gastrointestinal disease. Faecalibacterium prausnitzii (F. p) is a next-generation probiotic and could serve as a biomarker of gut eubiosis/dysbiosis to some extent. Alterations in the human oral and gut microbiomes are associated with viral respiratory infection. The aim of this study was to characterise the oral and fecal bacterial biomarker (i.e., F. n and F. p) in COVID-19 patients by qPCR and investigate the pharyngeal microbiome of COVID-19 patients through metagenomic next-generation sequencing (mNGS). RESULTS: Pharyngeal F. n was significantly increased in COVID-19 patients, and it was higher in male than female patients. Increased abundance of pharyngeal F. n was associated with a higher risk of a positive SARS-CoV-2 test (adjusted OR = 1.32, 95% CI = 1.06 ~ 1.65, P < 0.05). A classifier to distinguish COVID-19 patients from the healthy controls based on the pharyngeal F. n was constructed and achieved an area under the curve (AUC) of 0.843 (95% CI = 0.688 ~ 0.940, P < 0.001). However, the level of fecal F. n and fecal F. p remained unaltered between groups. Besides, mNGS showed that the pharyngeal swabs of COVID-19 patients were dominated by opportunistic pathogens. CONCLUSIONS: Pharyngeal but not fecal F. n was significantly increased in COVID-19 patients, clinicians should pay careful attention to potential coinfection. Pharyngeal F. n may serve as a promising candidate indicator for COVID-19.

Metal-Organic Gel Derived N-Doped Granular Carbon: Remarkable Toluene Uptake and Rapid Regeneration.

Porous carbon materials with chemical and thermal stability and high porosity have been widely used for volatile organic compound (VOC) purification. Designing granular carbon with remarkable adsorption capacity and rapid regeneration is of great significance for the capture of VOCs from high humidity air. Herein, a series of N-doped granular carbons were synthesized by direct carbonization of metal-organic gel (MOG). The N-doped granular carbons (C700 and C700K) feature high surface area, hierarchical pore, and abundant N,O multifunctional groups. The toluene adsorption capacity of C700K is highly improved (9.0 mmol/g toluene at P/P0 = 0.1) in comparison with MOG (4.81 mmol/g toluene at P/P0 = 0.1). The toluene breakthrough time of C700K is over 4 times longer than that of MOG at wet conditions (60% RH, 298 K), also much longer than that of widely used carbon materials, zeolites, and representative MOFs, including BPL activated carbon, coconut shell activated carbon, carbosieve, ZSM-5, and MIL-101(Cr). Furthermore, the N-doped granular carbons also exhibit excellent hydrophobicity and can be regenerated rapidly. The internal pore channel and desorption kinetics reveal that the effective diffusion length plays a critical role in the regeneration rate.

Epidemiology of norovirus gastroenteritis in hospitalized children under five years old in western China, 2015-2019.

OBJECTIVES: Norovirus is associated with one-fifth of all gastroenteritis cases, but basic epidemiological data is lacking, especially in developing countries. As long-term surveillance on norovirus gastroenteritis is scarce in western China, this study aims to update the epidemiological knowledge of norovirus gastroenteritis and to characterize the genotypes of norovirus strains. METHODS: Stool samples were collected from hospitalized children under 5 years old with gastroenteritis in Chengdu, China. All samples were tested for norovirus as well as rotavirus, sapovirus, enteric adenovirus, and astrovirus by real-time RT-PCR. RdRp and VP1 genes were sequenced in norovirus-positive samples to investigate viral phylogenies. RESULTS: Of the 1181 samples collected from 2015 to 2019, 242 (20.5%) were positive for norovirus. Among norovirus-positive cases, 65 cases had co-infection with another virus; norovirus/enteric adenovirus was most frequently detected (50.8%, 33/65). The highest positive rate was observed in children aged 13-18 months (23.7%, 68/287). Norovirus infection peaked in autumn (36.6%, 91/249), followed by summer (20.3%, 70/345). Pearson correlation analysis showed significant correlation between the norovirus-positive rate and humidity (r = 0.773, P < 0.05). GII.4 Sydney 2012 [P31] (48.5%, 79/163) and GII.3 [P12] (35.6%, 58/163) were the dominant norovirus strains. CONCLUSIONS: Norovirus has become one of the most common causes of viral gastroenteritis in children under 5 years old in western China. Continuous monitoring is imperative for predicting the emergence of new epidemic strains and for current vaccine development.

Detection of SARS-CoV-2 in fecal samples with different pretreatment methods and PCR kits.

BACKGROUND: Gastrointestinal symptoms are common in COVID-19 patients and SARS-CoV-2 RNA has been detected in the patients' feces, which could lead to fecal-oral transmission. Therefore, fecal sample testing with real-time RT-PCR is highly recommended as a routine test for SARS-CoV-2 infection. However, varying rates of detection in fecal sample have been reported. The aim of this study was to provide insights into the detection rates of SARS-CoV-2 in COVID-19 patients' fecal sample by using four real-time RT-PCR kits and two pretreatment methods (inactive and non-inactive). RESULTS: The detection rate of Trizol pretreatment group was slightly higher than that of Phosphate Buffered Saline (PBS) groups, showing that pretreatment and inactivation by Trizol had no influence to SARS-CoV-2 nucleic acid test (NAT) results. 39.29% detection rate in fecal sample by DAAN was obtained, while Bio-germ was 40.48%, Sansure 34.52%, and GeneoDx 33.33%. The former three kits had no significant difference. The DAAN kit detection rates of ORF1ab and N gene were nearly equal and Ct value distribution was more scattered, while the Bio-germ kit distribution was more clustered. The positive rate of SARS-COV-2 in fecal samples correlated with the severity of the disease, specifically, severe cases were less likely to be identified than asymptomatic infection in the DAAN group (adjusted OR 0.05, 95%CI = 0.00 ~ 0.91). CONCLUSIONS: Trizol should be of choice as a valid and safe method for pretreatment of fecal samples of SARS-CoV-2. All real-time RT-PCR kits assessed in this study can be used for routine detection of SARS-CoV-2 in fecal samples. While DAAN, with high NAT positive rate, could be the best out of the 4 kits used in this study. SARS-CoV-2 positive rate in fecal sample was related to the severity of illness.

Macroporous MnO2-based aerogel crosslinked with cellulose nanofibers for efficient ozone removal under humid condition.

Atmospheric ozone pollution receives worldwide concerns, and it is a big challenge to search for the practical ozone-decomposition catalyst with good moisture resistance. Herein, a light-weight and high-porosity MnO2-based hybrid aerogel was synthesized with cellulose nanofibers using a facile ice-template approach, followed by freeze-drying. In the three-dimensional framework, the cellulose nanofibers serve as the skeletons to disperse MnO2 particles, improving the exposure of active sites on MnO2. XPS, 1H NMR and ATR-FTIR demonstrate that MnO2 particles are effectively combined with cellulose nanofibers through hydrogen bonds, which originate from the abundant surface hydroxyl groups of both components. These consumed surface hydroxyl groups of MnO2 not only reduce the water adsorption but also avoid the generation of surface-adsorbed H2O via the reaction with ozone, thus alleviating the catalyst deactivation. In addition, the interconnected macroporous structure enables the rapid diffusion of ozone molecules and facilitates the passage of water molecules, which is conducive to the adsorption and decomposition of ozone on the active sites, i.e. surface oxygen vacancies. Thus, the high and stable ozone conversion was achieved for 150 ppb O3 under the relative humidity of 50% and the space velocity of 600 L·g-1·h-1 within 10 days at room temperature.

Reflection on lower rates of COVID-19 in children: Does childhood immunizations offer unexpected protection?

The incidence of COVID-19 in children and teenagers is only about 2% in China. Children had mild symptoms and hardly infected other children or adults. It is worth considering that children are the most vulnerable to respiratory pathogens, but fatal SARS-like virus had not caused severe cases among them. According to the pathological studies of COVID-19 and SARS, a sharp decrease in T lymphocytes leads to the breakdown of the immune system. The cellular immune system of children differs from that of adults may be the keystone of atypical clinical manifestations or even covert infection. The frequent childhood vaccinations and repeated pathogens infections might be resulting in trained immunity of innate immune cells, immune fitness of adaptive immune cells or cross-protection of antibodies in the children. Therefore, due to lack of specific vaccine, some vaccines for tuberculosis, influenza and pneumonia may have certain application potential for the front-line health workers in the prevention and control of COVID-19. However, for high-risk susceptible populations, such as the elderly with basic diseases such as hypertension and diabetes, it is necessary to explore the remedial effect of the planned immune process on their immunity to achieve the trained immunity or immune fitness, so as to improve their own antiviral ability.

In Situ Preparation of Amphibious ZnO Quantum Dots with Blue Fluorescence Based on Hyperbranched Polymers and their Application in Bio-Imaging.

A new strategy for preparing amphibious ZnO quantum dots (QDs) with blue fluorescence within hyper-branched poly(ethylenimine)s (HPEI) was proposed in this paper. By changing [Zn2+]/[OH-] molar ratio and heating time, ZnO QDs with a quantum yields (QY) of 30% in ethanol were obtained. Benefiting from the amphibious property of HPEI, the ZnO/HPEI nanocomposites in ethanol could be dissolved in chloroform and water, acquiring a QY of 53%, chloroform and 11% in water. By this strategy, the ZnO/HPEI nano-composites could be applied in not only in optoelectronics, but also biomedical fields (such as bio-imaging and gene transfection). The bio-imaging application of water-soluble ZnO/HPEI nanocomposites was investigated and it was found that they could easily be endocytosed by the COS-7 cells, without transfection reagent, and they exhibited excellent biological imaging behavior.

The impact of IFNL3 genotype on interferon treatment outcome in patients chronically infected with hepatitis B virus: A meta-analysis.

BACKGROUND: Polymorphisms near the interferon lambda 3 (IFNL3, also known as IL28B) have been proposed to be associated with interferon (IFN)-induced hepatitis C virus (HCV) clearance, but the impact of IFNL3 variations on the result of IFN-based therapy in chronic hepatitis B (CHB) infection is still poor understood. METHODS: The purpose of this study was to evaluate the relationship between the IFNL3 polymorphisms and the effectiveness of IFN therapy in patients infected with CHB by means of meta-analysis. PubMed and Embase were utilized to identify relevant studies. Odds ratio (OR) and 95% confidence interval (CI) were analysed together to assess the strength of the association. Subgroup analysis was mainly performed according to HBeAg. RESULTS: Twelve studies of 1645 CHB patients met the inclusion criteria and were selected in our meta-analysis. One polymorphism, rs12979860, near to the IFNL3 gene had significant association with the response of CHB patients to IFN-based therapy (OR = 2.35, 95% CI: 1.61-3.42 in allelic model). Another polymorphism, rs8099917, had a similar result (OR = 1.57, 95% CI: 1.03-2.40 in dominant model; and OR = 1.88, 95% CI: 1.21-2.90 in allelic model). When stratified by HBeAg, the antiviral outcome was markedly influenced by both two SNPs in HBeAg positive group (for rs12979860, OR = 1.90, 95% CI: 1.31-2.76 and OR = 2.07, 95% CI: 1.26-3.41 in dominant and allelic models respectively; for rs8099917, OR = 1.67, 95% CI: 1.04-2.67 in dominant model and OR = 1.77, 95% CI: 1.10-2.85 in allelic model). CONCLUSION: We concluded that two polymorphisms (rs12979860 and rs8099917) of IFNL3 may play a crucial role in the IFN-based treatment of CHB, especially in HBeAg positive group.

Isolation and structural elucidation of novel antimicrobial compounds from maggots of Chrysomyis megacephala Fabricius.

The excretions/secretions from the maggot of Chrysomyis megacephala Fabricius are traditionally used to treat serious infections in China. In this study, bioassay-guided fractionation led to the isolation of three novel antibacterial compounds (1-3), including important fluorinated compounds (3 and 5), together with other nine known compounds from 70% methanol extract of C. megacephala. The structures of the new compounds were elucidated by NMR spectroscopic analysis and high-resolution mass spectroscopy. The antibacterial activities of the isolated compounds were evaluated using agar disc diffusion method. New compounds 1 and 2 exhibited moderate activity against Bacillus subtilis with a minimum inhibitory concentration (MIC) of 250 µg mL(- 1). The most active compounds 3 and 5 displayed a broad spectrum of antimicrobial activity with an MIC of 125 µg mL(- 1) against G(+) and G(- ) bacteria. The structure of the above-mentioned novel compounds and their antimicrobial activities are herein reported for the first time from the natural product of insects.

[Hemagglutinin gene of influenza A (H3N2) virus from human samples in the 2009 influenza epidemic in Chengdu].

OBJECTIVE: To study the antigenic and genetic characteristics of influenza A (H3N2) virus in the 2009 influenza epidemics in Chengdu. METHODS: The influenza virus strains were isolated with MDCK cells from 4869 samples taken from the sentinel surveillance in 2009 in Chengdu. Hemagglutination inhibition (HI) and RT-PCR reaction tests were performed to guide the extraction of viral RNA from the culture fluid of the influenza A (H3N2) virus. The hemagglutinin gene was obtained by RT-PCR and sequenced. RESULTS: The separation rates of swine influenza H1N1, H3N2, H1N1, and B were 25.2%, 7.2%, 4.5%, and 1.5% respectively. The epidemic peaked in summer and autumn. Four amino acids changed in A, B, and D antigenic and receptor binding sites: site160N>K, site174K>R/N, site189K>Q, site277R>Q. Glycosylation sites were inserted to sitel60 or absent at site181 in some isolated strains. CONCLUSION: Swine influenza H1N1 viruses dominated the 2009 Chengdu epidemic, with H3N2, H1N1, and B strains coexisting. The influenza A(H3N2) viruses had gene variations due to antigenic drift.