Bactericidal efficacy of low concentration of vaporized hydrogen peroxide with validation in a BSL-3 laboratory

BACKGROUND

Highly infective pathogens are cultured and studied in biosafety laboratories. It is critical to thoroughly disinfect these laboratories to prevent laboratory infection. A whole-room, non-contact, reduced corrosion disinfection strategy using hydrogen peroxide was proposed and evaluated.

AIM

To evaluate the bactericidal efficacy of 8% and 10% vaporized hydrogen peroxide( VHP) in a laboratory setting with spores and bacteria as bioindicators.

METHODS

Spores of B. atrophaeus and B. stearothermophilus, along with bacteria E. coli, S. aureus, and S. epidermidis were placed in pre-selected locations in a sealed laboratory and an OXY-PHARM NOCOSPRAY2 vaporized hydrogen peroxide generator was applied. Spore killing efficacy was qualitatively evaluated, and bactericidal efficacy was quantitatively analyzed, and the mean log10 reduction was determined. Finally, the optimized disinfection strategy was verified in a BSL-3 laboratory.

FINDINGS

Significant reductions in microbial load were obtained for each of the selected spores and bacteria when exposed to VHP in concentrations of 8% and 10% for 2～3 h. S. aureus was found to be more resistant than E. coli and S. epidermidis. Tests with 8% hydrogen peroxide and exposure for more than 3 h completely killed B. atrophaeus on surfaces and equipment in the BSL-3 laboratory.

CONCLUSION

The vaporized hydrogen peroxide generator is superior in terms of good diffusivity and low corrosiveness and is time-effective in removing the disinfectant residue. This study provides reference for the precise disinfection of air and object surfaces in biosafety laboratories under varying conditions.

Economic burden of public health care and hospitalisation associated with COVID-19 in China

OBJECTIVES

This study aimed to evaluate the socio-economic burden imposed on the Chinese healthcare system during the coronavirus disease 2019 (COVID-19) pandemic.

STUDY DESIGN

A cross-sectional study was used to investigate how COVID-19 impacted health and medical costs in China. Data were derived from a subdivision of the Centers for Disease control and Prevention of China.

METHODS

We prospectively collected information from the Centers for Disease Control and Prevention and the designated hospitals to determine the cost of public health care and hospitalisation due to COVID-19. We estimated the resource use and direct medical costs associated with public health.

RESULTS

The average costs, per case, for specimen collection and nucleic acid testing (NAT [specifically, polymerase chain reaction {PCR}]) in low-risk populations were $29.49 and $53.44, respectively; however, the average cost of NAT in high-risk populations was $297.94 per capita. The average costs per 1000 population for epidemiological surveys, disinfectant, health education and centralised isolation were $49.54, $247.01, $90.22 and $543.72, respectively. A single hospitalisation for COVID-19 in China cost a median of $2158.06 ($1961.13-$2325.65) in direct medical costs incurred only during hospitalisation, whereas the total costs associated with hospitalisation of patients with COVID-19 were estimated to have reached nearly $373.20 million in China as of 20, May, 2020. The cost of public health care associated with COVID-19 as of 20, May, 2020 ($6.83 billion) was 18.31 times that of hospitalisation.

CONCLUSIONS

This study highlights the magnitude of resources needed to treat patients with COVID-19 and control the COVID-19 pandemic. Public health measures implemented by the Chinese government have been valuable in reducing the infection rate and may be cost-effective ways to control emerging infectious diseases.

Cell-Trappable BODIPY-NBD Dyad for Imaging of Basal and Stress-Induced H2S in Live Biosystems

H₂S is a gaseous signaling molecule that is involved in many physiological and pathological processes. In general, the level of intracellular H₂S (<1 μM) is much lower than that of GSH (∼1-10 mM), leading to the remaining challenge of selective detection and differentiation of endogenous H₂S in live biosystems. To this end, we quantitatively demonstrate that the thiolysis of NBD amine has much higher selectivity for H₂S over GSH than that of the reduction of aryl azide. Subsequently, we developed the first NBD-based cell-trappable probe 1 (AM-BODIPY-NBD) for highly selective and ultrasensitive imaging of intracellular H₂S. Probe 1 demonstrates a 207-fold fluorescence enhancement at 520 nm after reaction with H₂S/esterase to produce a bright BODIPY (quantum yield 0.42) and a detection limit of 15.7 nM. Probe 1 is water-soluble, cell-trappable, and not cytotoxic. Based on this excellent chemical tool, relative levels of basal H₂S in different cell lines were measured to reveal a positive correlation between endogenous H₂S and the metastatic potential of colon and breast cancer cells. In addition, H₂S biogenesis in vivo was also validated by probe 1 both in tobacco leaves under viral infection and in zebrafish after tail amputation. It is anticipated that probe 1 will have widespread applications in imaging and for investigating different H₂S-related biological processes and diseases.

Age and Sex Differences in the Association of Sleep Duration and Overweight/Obesity among Chinese Participants Age above 45 Years: A Cohort Study

OBJECTIVES

We aimed to evaluate the association between sleep duration and obesity and estimate the attributable risk of sleep in the China Health and Retirement Longitudinal Study surveys (CHARLS).

METHODS

A total of 9061 adults aged 45 years above from CHARLS (2011-2015) were included. The main outcome of this study was incident overweight/obesity specific to general and abdominal obesity. Overweight/obesity was defined as BMI ≥ 23.0 (kg/m2) and BMI≥27.5 (kg/m2), respectively. Abdominal obesity was defined as waist circumference ≥90 cm for men and ≥80 cm for women. Self-reported sleep durations were obtained using a structured questionnaire. We assessed hazard ratios (HRs) and 95% confidence intervals (CIs) as well as the population attributable fraction (PAF) for associations between sleep duration and obesity.

RESULTS

986 and 606 participants were identified as overweight and general obesity respectively, 1253 experienced abdominal obesity events. In multivariable-adjusted models, participants with daytime sleep of 0-30 minutes and more than 30 minutes associated with 30% (HR: 0.70, 95% CI: 0.56-0.87) and 35% (HR: 0.65, 95% CI: 0.55-0.78) decreased incident overweight risk respectively compared to those having no daytime sleep, this association also found among females and middle-aged, not males or elderly. Similarly, 0-30 minutes (HR: 0.68, 95% CI: 0.48-0.96) and more than 30 minutes of daytime sleep (HR: 0.73, 95% CI: 0.59-0.91) were associated with a reduced risk of abdominal obesity, similar results also found among females and middle-aged. Compared with 7-9 hours of nocturnal sleep, people who slept 5-7 hours had a reduced risk of overweight (HR: 0.59, 95% CI=0.47-0.74),but not found in subgroups. The hazard role of long nocturnal sleep for abdominal obesity was only found among elderly (HR: 2.33, 95% CI=1.35-4.04) and males (HR: 2.24, 95% CI=1.17-4.29). Compared with moderate total sleepers (7-9hours/day), participants with short total sleep duration exhibited an elevated risk of overweight (HR: 1.13, 95% CI=1.00-1.28), this also found among middle-aged. The PAF for inadequate total sleep duration (<7 hours/day) was 10.77% for overweight individuals.

CONCLUSIONS

Insufficient sleep duration was associated with an elevated risk of overweight only detected among middle-aged not elderly and other subgroups specific by age. The risks for abdominal obesity were increased for males and middle-aged with long nocturnal sleep. Daytime sleep may significantly reduce the risk of overweight and abdominal obesity in female and middle-aged individuals. The link between sleep duration and obesity requires further study.

[Clinical applicational comparison of digital impression and silicon rubber impression technique in posterior implant-supported single crown restoration]

Objective: To investigate the clinical effect and satisfaction of partially edentulous patients restored with posterior implant-supported single crown by digital impression technique and traditional silicon rubber impression, in order to provide clinical reference. Methods: Sixty-four partially edentulous patients who visited the Department of Prosthodontics, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University between March 2018 and January 2021 were enrolled. There were 31 male and 33 female, and the age of the group of patients was (49.3±13.3) years. The 113 implants placed in this group of patients were divided into digital impression group (n=70) and silicone rubber impression group (n=43) according to different impression techniques, and were restored with screw-retained full zirconia single crown, and the patients were followed up for 3-36 months after treatment. The implant survival rate, upper prosthesis, peri-implant soft tissue status, marginal bone loss and patients satisfaction were recorded to evaluate the clinical effects of two impression techniques in posterior implant-supported single crown. Results: In sixty-four patients, digital impression accounted for 62% (40/64), and silicon rubber impression accounted for 38% (24/64), the survival rate of 113 implants was 100% (113/113). The prevalence of interproximal contact loss, food impaction and mechanical complication of the upper full zirconia single crown restorations were 22.7% (41/181), 8.0% (9/113) and 2.7% (3/113) separately. All the mechanical complications were abutment screw loosening. All patients maintained good oral hygiene status, the incidences of peri-implantitis and peri-implant mucositis were 0.9% (1/113) and 4.4% (5/113) respectively. The marginal bone loss was (0.24±0.11) mm. The median of satisfaction visual analogue scale score in patients was 9-10, but no statistically significant differences of all the above results were observed between the two impression techniques (P>0.05). Conclusions: The clinical effect of partially edentulous patients restored with posterior implant-supported single crown using two different impression techniques is good and the satisfaction of patients is high, but the long-term clinical effect remains to be further observed.

Circular Antisense Oligonucleotides for Specific RNase-H-Mediated microRNA Inhibition with Reduced Off-Target Effects and Nonspecific Immunostimulation

Antisense microRNA oligodeoxynucleotides (AMOs) are powerful tools to regulate microRNA functions. Unfortunately, severe off-target effects are sometimes observed. Due to the special topological and enzymatic properties of circular oligodeoxynucleotides (c-ODNs), we rationally designed and developed circular AMOs, which effectively inhibited microRNA functions with high target specificity and low off-target effects. Binding and enzymatic assays indicated that small circular AMOs could selectively bind to and further digest the target mature miR 21, which suggested that the topological properties of circular c-ODNs significantly decreased their off-target effects as microRNA inhibitors. Compared with their linear corresponding phosphorothioated AMOs, circular phosphorothioated AMOs could more effectively reduce the amount of carcinogenic miR 21 and miR 222 and upregulate the expression levels of downstream antitumor proteins of PTEN and PDCD4. In addition, c-PS-antimiRs induced much less nonspecific immunostimulatory effects compared with their linear partner PS-ODNs, further indicating the advantages of circular ODNs in nonspecific immunostimulation.

Functional characterization of two diacylglycerol acyltransferase 1 genes in Mortierella alpina

Diacylglycerol acyltransferase (DGAT) is a crucial enzyme in the triacylglycerol (TAG) biosynthesis pathway. The oleaginous fungus Mortierella alpina can accumulate large amounts of arachidonic acid (ARA, C20:4) in the form of TAG. Therefore, it is important to study the functional characteristics of its DGAT. Two putative genes MaDGAT1A/1B encoding DGAT1 were identified in M. alpina ATCC 32222 genome by sequence alignment. Sequence alignment with identified DGAT1 homologs showed that MaDGAT1A/1B contain seven conserved motifs that are characteristic of the DGAT1 subfamily. Conserved domain analysis showed that both MaDGAT1A and MaDGAT1B belong to the Membrane-bound O-acyltransferases superfamily. The transforming with MaDGAT1A/1B genes could increase the accumulation of TAG in Saccharomyces cerevisiae to 4·47 and 7·48% of dry cell weight, which was 7·3-fold and 12·3-fold of the control group, respectively, but has no effect on the proportion of fatty acids in TAG. This study showed that MaDGAT1A/1B could effectively promote the accumulation of TAG and therefore may be used in metabolic engineering aimed to increase TAG production of oleaginous fungi.

Feasibility of cRGD conjugation at 5'-antisense strand of siRNA by phosphodiester linkage extension

Small interfering RNAs (siRNAs) are widely studied for their highly specific gene silencing activity. However, obstacles remain to the clinical application of siRNAs. Attaching conjugates to siRNAs can improve their stability and broaden their application, and most functional conjugates of siRNAs locate at the 3'-terminus of the sense or antisense strand. In this work, we found that conjugating a group at the 5'-terminus of the antisense strand via phosphodiester was practicable, especially when the group was a flexible moiety such as an alkyl linker. When conjugating a bulky ligand, such as cRGD, the length of the 5'-phosphodiester linker between the ligand and the 5'-terminus of the antisense strand was the key in terms of RNA interference (RNAi). With a relative longer linker, the conjugates showed potency similar to siRNA. A highly efficient transfection system composed of a neutral cytidinyl lipid (DNCA) and a gemini-like cationic lipid (CLD) was employed to deliver siRNAs or their conjugates. The cRGD conjugates showed superior targeting delivery and antitumor efficacy in vivo and also selective cellular uptake in vitro. This unity of encapsulation and conjugation strategy may provide potential strategies for siRNA-based gene therapy.

Effect of Water Chemistry on the Uptake of Co(II) on Graphene Oxide Investigated by Batch Technique

The uptake of Co(II) on graphene oxide (GO) by an adsorption process as a function of pH and ionic strength in the absence and presence of humic acid (HA) or fulvic acid (FA) was studied using batch technique. The results indicated that the uptake is strongly dependent on pH but independent of ionic strength. A stimulative effect of HA/FA on Co(II) uptake was found at pH < 7.0, whereas an inhibitory effect was observed at pH > 7.0. Kinetic studies suggest that Co(II) uptake on GO could be described more favorably by the pseudo-second-order kinetic model. The uptake isotherms can be described better by the Langmuir, Freundlich, and D-R models than by the linear model. The thermodynamic data calculated from the temperature-dependent uptake isotherms suggests that the uptake of Co(II) on GO is spontaneous and endothermic. Results of this work are of great importance for the environmental application of GO in the treatment of Co(II) from wastewater and indicated that GO is promising for the natural attenuation of Co(II) and related metal ions from aqueous solution.

Potential biomarkers and lncRNA-mRNA regulatory networks in invasive growth hormone-secreting pituitary adenomas

PURPOSE

Growth hormone-secreting pituitary adenomas (GH-PAs) are common subtypes of functional PAs. Invasive GH-PAs play a key role in restricting poor outcomes. The transcriptional changes in GH-PAs were evaluated.

METHODS

In this study, the transcriptome analysis of six different GH-PA samples was performed. The functional roles, co-regulatory network, and chromosome location of differentially expressed (DE) genes in invasive GH-PAs were explored.

RESULTS

Bioinformatic analysis revealed 101 DE mRNAs and 70 DE long non-coding RNAs (lncRNAs) between invasive and non-invasive GH-PAs. Functional enrichment analysis showed that epithelial cell differentiation and development pathways were suppressed in invasive GH-PAs, whereas the pathways of olfactory transduction, retinol metabolism, drug metabolism-cytochrome P450, and metabolism of xenobiotics by cytochrome P450 had an active trend. In the protein-protein interaction network, 11 main communities were characterized by cell- adhesion, -motility, and -cycle; transport process; phosphorus and hormone metabolic processes. The SGK1 gene was suggested to play a role in the invasiveness of GH-PAs. Furthermore, the up-regulated genes OR51B6, OR52E4, OR52E8, OR52E6, OR52N2, MAGEA6, MAGEC1, ST8SIA6-AS1, and the down-regulated genes GAD1-AS1 and SPINT1-AS1 were identified in the competing endogenous RNA network. The RT-qPCR results further supported the aberrant expression of those genes. Finally, the enrichment of DE genes in chromosome 11p15 and 12p13 regions were detected.

CONCLUSION

Our findings provide a new perspective for studies evaluating the underlying mechanism of invasive GH-PAs.

Liquid repellency enabled antipathogen coatings

Currently, Coronavirus Disease 2019 (COVID-19)-a respiratory contagion spreading through expiratory droplets-has evolved into a global pandemic, severely impacting the public health. Importantly, the emerging of immune evasion SARS-CoV-2 variants and the limited effect of current antivirals against SARS-CoV-2 in clinical trials suggested that alternative strategies in addition to the conventional vaccines and antivirals are required to successfully control the COVID-19 pandemic. Here, we propose to use liquid-repellent coatings to prevent the spread of the disease in the absence of effective vaccines, antimicrobial agents, or therapeutics, wherein the deposition and penetration of pathogen droplets are prohibited. We use SARS-CoV-2 as a model pathogen and find that SARS-CoV-2 remnants are reduced by seven orders of magnitude on coated surfaces, yielding a repelling efficacy far outperforming the inactivation rate of disinfectants. The SARS-CoV-2 remnant scales exponentially with the liquid/solid adhesion, uncovering the mechanism and effective means for minimizing pathogen attachment. The antipathogen coating that both repels and inactivates pathogens is demonstrated by incorporating the super-liquid-repellent coating with antipathogen additives. Together with its versatility over a wide range of substrates and pathogens, the novel antipathogen coating is of considerable value for infection control in everyday life as well as during pandemics.

[Identification of potential regulatory genes for embryonic stem cell self-renewal and pluripotency by random forest]

OBJECTIVE

To identify novel genes associated with self-renewal and pluripotency of mouse embryonic stem cells(mESCs)by integrating multiomics data based on machine learning methods.

METHODS

We integrated multiomics information of mESCs involving transcriptome, histone modifications, chromatin accessibility, transcription factor binding and architectural protein binding, and compared the signal differences between known stem cell self-renewal and pluripotency genes and other genes.By integrating these multiomics data, we established prediction models based on several machine learning classifiers including random forests and performed 5-fold cross validations.The model was trained using the training dataset containing two thirds of the input samples, and the remaining one third of the input samples were used as the test dataset to assess the performance of the model in independent tests.Finally, the results predicted by the model were validated through gene function annotation and cell function experiments including cell viability assay, colony formation assay and cell cycle analysis.

RESULTS

Compared with the random genes, the genes known to be associated with self-renewal and pluripotency of mESCs in the multiomics data showed significantly different features.Random forest outperformed the other machine learning algorithms tested on these multiomics data, with an area under the curve (AUC) of 0.883±0.018 for cross validation and an AUC of 0.880±0.028 for independent test.Based on this model, we identified 893 potential regulatory genes associated wwith self-renewal and pluripotency of mESCs, which were similar to the known genes in functional annotation.Known-down of the predicted novel regulator gene Cct6a resulted in significant decreases in the cell viability of mESCs (P < 0.0001) and the number of cell clones (P < 0.01), significantly increased the number of cells in G1 phase (P < 0.01) and decreasedthe number of S phase cells (P < 0.05).Knockdown of Cct6a also led to failure of positive alkaline phosphatase staining of the mESCs.

CONCLUSION

Machine learning model based on multiomics data can be used to predict potential self-renewal and pluripotency regulators with high performance.By using this model, we predicted potential self-renewal and pluripotency regulatory genes including Cct6a and applied experimental validation.This model provides new insights into the regulatory mechanism of mESCs and contribute to stem cell research.

Accurate prediction and genome-wide association analysis of digital intramuscular fat content in longissimus muscle of pigs

Intramuscular fat (IMF) content is a critical indicator of pork quality that affects directly the purchasing desire of consumers. However, to measure IMF content is both laborious and costly, preventing our understanding of its genetic determinants and improvement. In the present study, we constructed an accurate and fast image acquisition and analysis system, to extract and calculate the digital IMF content, the proportion of fat areas in the image (PFAI) of the longissimus muscle of 1709 animals from multiple pig populations. PFAI was highly significantly correlated with marbling scores (MS; 0.95, r²  = 0.90), and also with IMF contents chemically defined for 80 samples (0.79, r²  = 0.63; more accurate than direct analysis between IMF contents and MS). The processing time for one image is only 2.31 s. Genome-wide association analysis on PFAI for all 1709 animals identified 14 suggestive significant SNPs and 1 genome-wide significant SNP. On MS, we identified nine suggestive significant SNPs, and seven of them were also identified in PFAI. Furthermore, the significance (-log P) values of the seven common SNPs are higher in PFAI than in MS. Novel candidate genes of biological importance for IMF content were also discovered. Our imaging systems developed for prediction of digital IMF content is closer to IMF measured by Soxhlet extraction and slightly more accurate than MS. It can achieve fast and high-throughput IMF phenotype, which can be used in improvement of pork quality.

Efficient Inhibition of SARS-CoV-2 Using Chimeric Antisense Oligonucleotides through RNase L Activation*

There is an urgent need to develop antiviral drugs and alleviate the current COVID-19 pandemic. Herein we report the design and construction of chimeric oligonucleotides comprising a 2'-OMe-modified antisense oligonucleotide and a 5'-phosphorylated 2'-5' poly(A)₄ (4A_2-5 ) to degrade envelope and spike RNAs of SARS-CoV-2. The oligonucleotide was used for searching and recognizing target viral RNA sequence, and the conjugated 4A_2-5 was used for guided RNase L activation to sequence-specifically degrade viral RNAs. Since RNase L can potently cleave single-stranded RNA during innate antiviral response, degradation efficiencies with these chimeras were twice as much as those with only antisense oligonucleotides for both SARS-CoV-2 RNA targets. In pseudovirus infection models, chimera-S4 achieved potent and broad-spectrum inhibition of SARS-CoV-2 and its N501Y and/or ΔH69/ΔV70 mutants, indicating a promising antiviral agent based on the nucleic acid-hydrolysis targeting chimera (NATAC) strategy.