High genetic barrier to SARS-CoV-2 polyclonal neutralizing antibody escape.

The number and variability of the neutralizing epitopes targeted by polyclonal antibodies in individuals who are SARS-CoV-2 convalescent and vaccinated are key determinants of neutralization breadth and the genetic barrier to viral escape1-4. Using HIV-1 pseudotypes and plasma selection experiments with vesicular stomatitis virus/SARS-CoV-2 chimaeras5, here we show that multiple neutralizing epitopes, within and outside the receptor-binding domain, are variably targeted by human polyclonal antibodies. Antibody targets coincide with spike sequences that are enriched for diversity in natural SARS-CoV-2 populations. By combining plasma-selected spike substitutions, we generated synthetic 'polymutant' spike protein pseudotypes that resisted polyclonal antibody neutralization to a similar degree as circulating variants of concern. By aggregating variant of concern-associated and antibody-selected spike substitutions into a single polymutant spike protein, we show that 20 naturally occurring mutations in the SARS-CoV-2 spike protein are sufficient to generate pseudotypes with near-complete resistance to the polyclonal neutralizing antibodies generated by individuals who are convalescent or recipients who received an mRNA vaccine. However, plasma from individuals who had been infected and subsequently received mRNA vaccination neutralized pseudotypes bearing this highly resistant SARS-CoV-2 polymutant spike, or diverse sarbecovirus spike proteins. Thus, optimally elicited human polyclonal antibodies against SARS-CoV-2 should be resilient to substantial future SARS-CoV-2 variation and may confer protection against potential future sarbecovirus pandemics.

Anti-SARS-CoV-2 receptor-binding domain antibody evolution after mRNA vaccination.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection produces B cell responses that continue to evolve for at least a year. During that time, memory B cells express increasingly broad and potent antibodies that are resistant to mutations found in variants of concern1. As a result, vaccination of coronavirus disease 2019 (COVID-19) convalescent individuals with currently available mRNA vaccines produces high levels of plasma neutralizing activity against all variants tested1,2. Here we examine memory B cell evolution five months after vaccination with either Moderna (mRNA-1273) or Pfizer-BioNTech (BNT162b2) mRNA vaccine in a cohort of SARS-CoV-2-naive individuals. Between prime and boost, memory B cells produce antibodies that evolve increased neutralizing activity, but there is no further increase in potency or breadth thereafter. Instead, memory B cells that emerge five months after vaccination of naive individuals express antibodies that are similar to those that dominate the initial response. While individual memory antibodies selected over time by natural infection have greater potency and breadth than antibodies elicited by vaccination, the overall neutralizing potency of plasma is greater following vaccination. These results suggest that boosting vaccinated individuals with currently available mRNA vaccines will increase plasma neutralizing activity but may not produce antibodies with equivalent breadth to those obtained by vaccinating convalescent individuals.

Inhibition of major histocompatibility complex-I antigen presentation by sarbecovirus ORF7a proteins.

Viruses employ a variety of strategies to escape or counteract immune responses, including depletion of cell surface major histocompatibility complex class I (MHC-I), that would ordinarily present viral peptides to CD8+ cytotoxic T cells. As part of a screen to elucidate biological activities associated with individual severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) viral proteins, we found that ORF7a reduced cell surface MHC-I levels by approximately fivefold. Nevertheless, in cells infected with SARS-CoV-2, surface MHC-I levels were reduced even in the absence of ORF7a, suggesting additional mechanisms of MHC-I down-regulation. ORF7a proteins from a sample of sarbecoviruses varied in their ability to induce MHC-I down-regulation and, unlike SARS-CoV-2, the ORF7a protein from SARS-CoV lacked MHC-I downregulating activity. A single amino acid at position 59 (T/F) that is variable among sarbecovirus ORF7a proteins governed the difference in MHC-I downregulating activity. SARS-CoV-2 ORF7a physically associated with the MHC-I heavy chain and inhibited the presentation of expressed antigen to CD8+ T cells. Specifically, ORF7a prevented the assembly of the MHC-I peptide loading complex and caused retention of MHC-I in the endoplasmic reticulum. The differential ability of ORF7a proteins to function in this way might affect sarbecovirus dissemination and persistence in human populations, particularly those with infection- or vaccine-elicited immunity.

Organic-Inorganic Rare-Earth Double Perovskite Ferroelectric with Large Piezoelectric Response and Ferroelasticity for Flexible Composite Energy Harvesters.

Hybrid organic-inorganic perovskite (HOIP) ferroelectric materials have great potential for developing self-powered electronic transducers owing to their impressive piezoelectric performance, structural tunability and low processing temperatures. Nevertheless, their inherent brittle and low elastic moduli limit their application in electromechanical conversion. Integration of HOIP ferroelectrics and soft polymers is a promising solution. In this work, a hybrid organic-inorganic rare-earth double perovskite ferroelectric, [RM3HQ]2RbPr(NO3)6 (RM3HQ = (R)-N-methyl-3-hydroxylquinuclidinium) is presented, which possesses multiaxial nature, ferroelasticity and satisfactory piezoelectric properties, including piezoelectric charge coefficient (d33) of 102.3 pC N-1 and piezoelectric voltage coefficient (g33) of 680 × 10-3 V m N-1. The piezoelectric generators (PEG) based on composite films of [RM3HQ]2RbPr(NO3)6@polyurethane (PU) can generate an open-circuit voltage (Voc) of 30 V and short-circuit current (Isc) of 18 µA, representing one of the state-of-the-art PEGs to date. This work has promoted the exploration of new HOIP ferroelectrics and their development of applications in electromechanical conversion devices.

Study design and rationale of COMPETE: Comparison of the effect of medication therapy in alleviating migraine with patent foramen ovale.

BACKGROUND: Previous studies have examined the impact of antithrombotic agents on Patent Foramen Ovale (PFO) in relation to migraine. However, differences in effectiveness of different antithrombotic agents and traditional migraine medications are not known. METHODS/DESIGN: This study is an investigator-initiated, randomized, multicenter, single-masked (outcomes assessor), and active-controlled parallel-group trial (ClinicalTrials.gov Identifier: NCT05546320), with the objective of evaluating the prevention efficacy of antithrombotic agents compared to first-line migraine medication in PFO patients. The trial involves 1,000 migraine patients with a right-to-left shunt at the atrial level, randomized in a 1:1:1:1 fashion to receive either aspirin 300 mg QD, clopidogrel 75 mg QD, rivaroxaban 20 mg QD, or the active-control metoprolol 25 mg BID. The primary efficacy end point is the response rate, defined as a 50% or greater reduction in the average migraine attack days per month or in the average number of migraine attacks per month at 12-week visit compared to baseline. CONCLUSIONS: The COMPETE trial aims to provide valuable insights into the comparative effectiveness of antithrombotic agents and standard migraine therapies in patients with PFO. This study holds the promise of advancing treatment approaches for individuals having migraines associated with PFO, thus addressing an important gap in current migraine management strategies.

Outcomes of Transcatheter Closure of Congenital Left Circumflex Coronary Artery Fistula.

BACKGROUND: Congenital left circumflex coronary artery fistula (LCX-CAF) is a relatively rare type of coronary artery fistula (CAF); little is known about the outcomes of transcatheter closure (TCC) of LCX-CAF.Methods and Results: All consecutive patients admitted to Fuwai Hospital and scheduled for TCC of LCX-CAF between January 2012 and December 2022 were reviewed retrospectively. Of the 25 consecutive patients (mean [±SD] age 34±20 years; 48% male) admitted and scheduled for TCC of congenital LCX-CAF, the procedure was feasible in 22 (77.3%). The mean (±SD) diameter of the fistulas was 6.99±2.04 mm; 21 (84%) patients had a large fistula (i.e., diameter >2-fold greater than non-feeding coronary artery). Occluders were deployed via a transarterial approach and arteriovenous loop in 6 (27.3%) and 16 (72.7%) patients, respectively. No procedural complications were recorded. Although the procedural success rates are similar for single LCX-CAF and left anterior descending CAF (81.25% vs. 92.86%; P=0.602), the mean time from initial angiography to first occluder deployment is significantly longer for LCX-CAF (83.06±36.07 vs. 36.00±9.49 min; P<0.001). The mean (±SD) follow-up time was 62.2±45.5 months. The incidence of myocardial infarction and recanalization of the fistula was 4.5% (1/22) and 9.1% (2/22), respectively. CONCLUSIONS: TCC of LCX-CAF is a feasible and effective alternative to surgical repair, with comparable outcomes in selected patients. Optimal medical therapy to prevent post-closure myocardial infarction requires further investigation.

Irreversible Inactivation of SARS-CoV-2 by Lectin Engagement with Two Glycan Clusters on the Spike Protein.

Host cell infection by SARS-CoV-2, similar to that by HIV-1, is driven by a conformationally metastable and highly glycosylated surface entry protein complex, and infection by these viruses has been shown to be inhibited by the mannose-specific lectins cyanovirin-N (CV-N) and griffithsin (GRFT). We discovered in this study that CV-N not only inhibits SARS-CoV-2 infection but also leads to irreversibly inactivated pseudovirus particles. The irreversibility effect was revealed by the observation that pseudoviruses first treated with CV-N and then washed to remove all soluble lectin did not recover infectivity. The infection inhibition of SARS-CoV-2 pseudovirus mutants with single-site glycan mutations in spike suggested that two glycan clusters in S1 are important for both CV-N and GRFT inhibition: one cluster associated with the RBD (receptor binding domain) and the second with the S1/S2 cleavage site. We observed lectin antiviral effects with several SARS-CoV-2 pseudovirus variants, including the recently emerged omicron, as well as a fully infectious coronavirus, therein reflecting the breadth of lectin antiviral function and the potential for pan-coronavirus inactivation. Mechanistically, observations made in this work indicate that multivalent lectin interaction with S1 glycans is likely a driver of the lectin infection inhibition and irreversible inactivation effect and suggest the possibility that lectin inactivation is caused by an irreversible conformational effect on spike. Overall, lectins' irreversible inactivation of SARS-CoV-2, taken with their breadth of function, reflects the therapeutic potential of multivalent lectins targeting the vulnerable metastable spike before host cell encounter.

Physiological and biochemical regulation of tobacco by oxathiapiprolin under Phytophthora nicotianae infection.

As a fungicide, oxathiapiprolin has excellent effects on diseases caused by oomycetes. Fungicides generally protect crops by inhibiting pathogens, but little research has addressed the effects of fungicides on crops. This study combined transcriptomic and metabolomic analyses to systematically analyze the physiological regulatory mechanisms of oxathiapiprolin on tobacco under Phytophthora nicotianae infection. The results showed that under P. nicotianae infection, tobacco's photosynthetic rate and antioxidant enzyme activity increased after the application of oxathiapiprolin. Omics results showed that the genes related to carbon metabolism, disease-resistant proteins, and amino acid synthesis were highly expressed, and the amino acid content increased in tobacco leaves. This study is the first comprehensive investigation of the physiological regulatory effects of oxathiapiprolin on tobacco in response to P. nicotianae infection. These findings provide a basis for the balance between regulating tobacco growth and development and enhancing disease resistance under the stimulation of oxathiapiprolin and provide new research and development opportunities for identifying new disease-resistance genes and the development of high-yielding disease-resistant crop varieties.

Method validation and dissipation kinetics of the novel HPPD-inhibiting herbicide cypyrafluone in winter wheat using QuEChERS method coupled with UPLC-MS/MS.

Cypyrafluone, a novel hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide, can successfully control a wide species of grass and broadleaf weed in wheat fields. However, the dissipation behaviors and terminal residues of cypyrafluone in wheat fields remain unclear. Here, a simple, accurate, and dependable approach for the analysis of cypyrafluone in soil, wheat plant, and grain was constructed utilizing an adapted QuEChERS extraction combined with UPLC-MS/MS. For accurate quantification, matrix-matched calibrations with high linearity (R2 >0.99) were employed to eliminate matrix interference. The method possessed high accuracy with recoveries in the range of 85.5%- 100.6% and precision with relative standard deviations < 14.3%, as well as high sensitivity with limits of quantifications of 0.001 mg kg-1 in the three matrixes. The dissipation kinetics and terminal residues of cypyrafluone were determined at two separate locations with different climates, soil types and cropping systems in 2018. The half-lives of cypyrafluone in soil and wheat plant were 1.47-1.55 d and 1.00-1.03 d, respectively. At harvest, the terminal residue values of cypyrafluone detected in wheat plants were 0-0.0025 mg kg-1 and 0.0044-0.0057 mg kg-1 at the recommended dose and 1.5 times of the recommended dose, respectively, and 0.0049 mg kg-1 of this herbicide was detected in grain at 1.5 times of the recommended dose, which was below the maximum residue limit (MRL). Finally, the risk quotient for cypyrafluone ranged from 0.33% to 0.81% (<1) for different age groups in China, indicating that the impact of residues from the cypyrafluone application on wheat was acceptable. These findings above will offer scientific guidelines for cypyrafluone application in the wheat field ecosystem.

Direct toxicity of the herbicide florasulam against Chlorella vulgaris: An integrated physiological and metabolomic analysis.

Herbicides are the agents of choice for use in weed control; however, they can enter the aquatic environment, with potentially serious consequences for non-target organisms. Despite the possible deleterious effects, little information is available regarding the ecotoxicity of the herbicide florasulam toward aquatic organisms. Accordingly, in this study, we investigated the toxic effect of florasulam on the freshwater microalga Chlorella vulgaris and sought to identify the underlying mechanisms. For this, we employed a growth inhibition toxicity test, and then assessed the changes in physiological and metabolomic parameters, including photosynthetic pigment content, antioxidant system, intracellular structure and complexity, and metabolite levels. The results showed that treatment with florasulam for 96 h at the concentration of 2 mg/L, 2.84 mg/L, and 6 mg/L in medium significantly inhibited algal growth and photosynthetic pigment content. Moreover, the levels of reactive oxygen species were also increased, resulting in oxidative damage and the upregulation of the activities of several antioxidant enzymes. Transmission electron microscopic and flow cytometric analysis further demonstrated that exposure to florasulam (6 mg/L) for 96 h disrupted the cell structure of C. vulgaris, characterized by the loss of cell membrane integrity and alterations in cell morphology. Changes in amino acid metabolism, carbohydrate metabolism, and the antioxidant system were also observed and contributed to the suppressive effect of florasulam on the growth of this microalga. Our findings regarding the potential risks of florasulam in aquatic ecosystems provide a reference for the safe application of this herbicide in the environment.

Oxidative stress and detoxification mechanisms of earthworms (Eisenia fetida) after exposure to flupyradifurone in a soil-earthworm system.

Flupyradifurone (FLU) has great application potential in agricultural production as a new generation of neonicotinoid insecticide after imidacloprid. Nevertheless, the toxic effects of FLU on non-target soil organisms remain unclear, resulting in considerable environmental risks. We evaluated the acute and subchronic toxicities of FLU to earthworms. The results of acute toxicity show that the median lethal concentration (LC50) values (14 d) of FLU were 186.9773 mg kg-1 for adult earthworms and 157.6502 mg kg-1 for juveniles, respectively. The subchronic toxicity of FLU that focused on the activities of antioxidant and detoxication enzymes showed the superoxide dismutase (SOD), catalase (CAT), and glutathione-S transferase (GST) activities in earthworms increased while the peroxidase (POD) and acetylcholinesterase (AChE) activities decreased after exposure to FLU. Oxidative damage analyses revealed that the reactive oxygen species (ROS) level and malonaldehyde (MDA) content in earthworms were increased by FLU, resulting in DNA damage. Transcriptomics and RT-qPCR confirmed that FLU influenced the expression of genes related to antioxidant response and detoxification of earthworms. Ultimately detoxification metabolism, environmental information processing, cell processes, and immune system pathways are significantly enriched to respond jointly to FLU. Our study fills the gaps in the toxicity of FLU to earthworms, providing a basis for its risk assessment of soil ecosystems and non-target biological toxicity.

Transcriptomics and enzymology combined five gene expressions to reveal the responses of earthworms (Eisenia fetida) to the long-term exposure of cyantraniliprole in soil.

Cyantraniliprole is a novel diamide insecticide that acts upon the ryanodine receptor (RyR) and has broad application prospects. Accordingly, it is very important to evaluate the toxicity of cyantraniliprole to earthworms (Eisenia fetida) because of their vital role in maintaining a healthy soil ecosystem. In this study, an experiment was set up, using four concentrations (0.1, 1, 5, and 10 mg/kg) and solvent control group (0 mg/kg), to investigate the ecotoxicity of cyantraniliprole to earthworms. Our results showed that, after 28 days of exposure to cyantraniliprole, both cocoon production and the number of juvenile earthworms had decreased significantly at concentrations of either 5 or 10 mg/kg. On day 14, we measured the activities of digestive enzymes and ion pumps in the intestinal tissues of earthworms. These results revealed that cyantraniliprole exposure caused intestinal damage in earthworm, specifically changes to its intestinal enzyme activity and calcium ion content. Cyantraniliprole could lead to proteins' carbonylation under the high-dose treatments (i.e., 5 mg/kg, 10 mg/kg). At the same time, we also found that cyantraniliprole can cause the abnormal expression of key functional genes (including HSP70, CAT, RYR, ANN, and CAM genes). Moreover, the transcriptomics data showed that exposure to cyantraniliprole would affect the synthesis of carbohydrates, proteins and lipids, as well as their absorption and transformation, while cyantraniliprole would also affect signal transduction. In general, high-dose exposure to cyantraniliprole causes reproductive toxicity, genotoxicity, and intestinal damage to earthworms.

Effects of the novel HPPD-inhibitor herbicide QYM201 on enzyme activity and microorganisms, and its degradation in soil.

QYM201 is a 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibiting herbicide recently registered in China for controlling grass and broadleaf weeds in wheat. It is a novel herbicide, and its potential harm to soil ecosystems has not yet been reported. This study investigates the influence of QYM201 on soil enzyme activity and microorganism quantities in two different soils at concentrations of 0.1, 1, and 5 mg kg-1 soil. Results indicate that QYM201 initially inhibited soil protease, urease, and sucrase activity and this effect increased with concentration. During the later stages of incubation, inhibitory effects gradually weakened and by the end of the experiment (45 days), enzyme activity was restored to control levels. Catalase activity was stimulated by QYM201, with significant differences observed between the QYM201-treated groups and the control at the onset of exposure. This stimulation effect decreased during the later stages of the experiment. However, catalase activity was still significantly higher at the end of the experiment compared to the control. The effects of QYM201 on soil microorganisms differed. Initially, bacteria and actinomycetes quantities were decreased by QYM201 (10 days). As the incubation progressed, microorganism quantities in the lower concentration groups (0.1 and 1 mg kg-1 soil) were restored to control levels, while those of the high concentration group (5 mg kg-1 soil) did not fully recover. QYM201 did not significantly impact the quantity of fungi. The half-life and degradation rate constant (k) of QYM201 for the two studied soil types were 23.1 days and 16.1 days, and 0.030 and 0.043 day-1, respectively.

Transcatheter Closure of Patent Ductus Arteriosus under Echocardiography Guidance: A Randomized Controlled Noninferiority Trial.

BACKGROUND: Percutaneous occlusion under fluoroscopy guidance has become the preferred method for the treatment of patent ductus arteriosus (PDA). To avoid radiation exposure and contrast agent use, PDA occlusion under transthoracic echocardiography (TTE) guidance was conducted. OBJECTIVES: We assessed the hypothesis that the success rate of percutaneous PDA occlusion under TTE was noninferior to that under fluoroscopy guidance. METHODS: In this single-center trial, 100 patients were randomly assigned in a 1 : 1 ratio to the TTE group (n = 50) or to the fluoroscopy group (n = 50). The primary endpoint was the success rate of occlusion, with the noninferiority margin set at 8% for the between-group difference in intention-to-treat analysis. Secondary endpoints were hospitalization duration, cost, procedure time, and rate of adverse events including occluder migration, hemolysis, peripheral vascular complications, and residual shunt at 1-month and 12-month follow-up. RESULTS: Patient, defect, and device characteristics were similarly distributed between groups. The success rate of occlusion was 98% for the TTE group and 100% for the fluoroscopy group (absolute difference: -2%; 95% confidence interval: -5.9% to 1.9%). Cost and procedure duration were significantly lower in the TTE group, without adverse events in either group at a median of 12.0 months (range, 10.0-15.5 months) of follow-up. CONCLUSION: Percutaneous PDA occlusion can be performed via TTE guidance safely and effectively, and the success rate of the TTE-guided procedure was noninferior to that under fluoroscopy guidance, with reduced cost and procedure time. The trial is registered with http://www.chictr.org.cn (ChiCTR-ICR-15006334).

Personalized Three-Dimensional Printing and Echoguided Procedure Facilitate Single Device Closure for Multiple Atrial Septal Defects.

BACKGROUND: To evaluate the feasibility of using a single device to close multiple atrial septal defects (ASDs) under the guidance of transthoracic echocardiography (TTE) and with the aid of three-dimensional (3D) printing models. METHODS: Sixty-two patients with multiple ASDs were retrospectively analyzed. Thirty of these patients underwent TTE-guided closure (3D printing and TTE group) after a simulation of occlusion in 3D printing models. The remaining 32 patients underwent ASD closure under fluoroscopic guidance (conventional group). Closure status was assessed immediately and at 6 months after device closure. RESULTS: Successful transcatheter closure with a single device was achieved in 26 patients in the 3D printing and TTE group and 27 patients in the conventional group. Gender, age [18.8 ± 15.9 (3-51) years in the 3D printing and TTE group; 14.0 ± 11.6 (3-50) years in the conventional group], mean maximum distance between defects, prevalence of 3 atrial defects and large defect distance (defined as distance ≥7 mm), and occluder size used were similarly distributed between groups. However, the 3D printing and TTE group had lower frequency of occluder replacement (3.8% vs 59.3%, p < 0.0001), prevalence of mild residual shunts (defined as <5 mm) immediately (19.2% vs 44.4%, p < 0.05) and at 6 months (7.7% vs 29.6%, p < 0.05) after the procedure, and cost (32960.8 ± 2018.7 CNY vs 41019.9 ± 13758.2 CNY, p < 0.01). CONCLUSION: The combination of the 3D printing technology and ultrasound-guided interventional procedure provides a reliable new therapeutic approach for multiple ASDs, especially for challenging cases with large defect distance.

Toxicity of thifluzamide in earthworm (Eisenia fetida).

An increase in the area treated with the fungicide thifluzamide has triggered concerns for soil ecosystem service providers such as earthworms. Here, we assessed effects of thifluzamide on earthworm (Eisenia fetida) biomarker indicators of stress responses and reproduction following exposure to 0, 0.1, 1.0, and 10.0 mg of thifluzamide kg-1 soil for 7, 14, 21, and 28 d (biomarker indicators) and 30 d (reproduction). Growth and reproduction were inhibited by exposure to thifluzamide at 10.0 mg/kg, and the activities of succinate dehydrogenase (SDH) and respiratory chain complex II were inhibited by exposure to 1.0 and 10.0 mg/kg thifluzamide for the majority of the 28-d experiment. Reactive oxygen species (ROS) increased across all thifluzamide treatments, and the activities of superoxide dismutase (SOD) and glutathione-S-transferase (GST) tended to be inhibited by thifluzamide. Upon exposure to thifluzamide, the activities of catalase (CAT) and guaiacol peroxidase (POD) initially increased and then decreased. Increased levels of malondialdehyde (MDA) were detected only at seven days after exposure, and genotoxicity increased as the thifluzamide concentration increased. The results suggest that thifluzamide presents a potential risk to earthworms at the concentration of 10.0 mg/kg, and its use should be moderated to reduce damage to soil ecosystem function.

Target-site and non-target-site-based resistance to tribenuron-methyl in multiply-resistant Myosoton aquaticum L.

Myosoton aquaticum L., a widespread and competitive winter weed of wheat in China, has evolved resistance to many classes of herbicides. In one M. aquaticum population (AH03), collected from Anhui Province, where tribenuron-methyl and florasulam had been used to control this weed resistance to both herbicides had evolved. Compared with the sensitive population, HN03(S), the resistant (R) population, AH03, was highly resistant to tribenuron-methyl, flucarbazone-Na and pyroxsulam, moderately resistant to pyrithiobac­sodium, and florasulam, and had low resistance to diflufenican. AH03 was still controlled by imazethapyr, 2,4-D butylate, fluroxypyr-meptyl, and isoproturon. Pretreatment with the P450 inhibitor malathion reduced the GR50 value of tribenuron-methyl by 43% in the R population, and by 25% in the S population. This indicates that P450-mediated enhanced metabolism is one likely mechanism for tribenuron-methyl resistance in M. aquaticum. Glutathione-S-transferase (GST) activity could be induced by tribenuron-methyl in both the R and S populations. However, both the basal and induced GST activity of the R population was lower than that of the S population. The in vitro ALS assay confirmed that the ALS from the R plants showed a high resistance (52.93-fold) to tribenuron-methyl. ALS gene sequencing revealed a Pro197Ala substitution in the R plants. Based on the ALS gene sequence analysis, molecular markers were also developed to identify the specific Pro197Ala mutation. This population of M. aquaticum has multiple resistance and target-site (ALS Pro197Ala) and non-target-site resistance mechanisms contribute to tribenuron-methyl resistance.

A novel totally biodegradable device for effective atrial septal defect closure: A 2-year study in sheep.

OBJECTIVE: To evaluate the feasibility, efficacy, and safety of a fully biodegradable poly lactic acid (PLA)-based occluder for atrial septal defect (ASD) closure in an animal model. METHODS: ASDs, approximately 12-mm in diameter, were generated in sheep (n = 18) by needle puncture and balloon dilatation. For ASD closure, occluders were implanted by percutaneous transcatheter approach under echocardiographic guidance. Outcomes were evaluated by transthoracic echocardiography, electrocardiography, blood testing, and histology within the follow-up period ranging from 1 month to 2 years. RESULTS: All occluders were successfully implanted. During follow-up, no animal died; rectal temperatures, blood test results, and electrocardiograms were within normal ranges; and transthoracic echocardiograms, macroscopic studies, and histopathological and electron microscopic examination demonstrated that the occluders were well positioned, with no shifting, residual shunts, severe inflammation, thrombus formation, atrioventricular valve insufficiency, cardiac erosion or arrhythmias. The occluders gradually embedded into the endocardial tissue of the hosts with complete endothelialization and disk absorption at 12 months, and a distinct molecular weight decrease of the framework (to 9% of initial) at 24 months after implantation. CONCLUSIONS: In a sheep model, the use of totally biodegradable occluders appears feasible, efficacious and safe for ASD closure. Studies in humans are ongoing.

Single-Cell and Single-Cycle Analysis of HIV-1 Replication.

The dynamics of the late stages of the HIV-1 life cycle are poorly documented. Viral replication dynamics are typically measured in populations of infected cells, but asynchrony that is introduced during the early steps of HIV-1 replication complicates the measurement of the progression of subsequent steps and can mask replication dynamics and their variation in individual infected cells. We established microscopy-based methods to dynamically measure HIV-1-encoded reporter gene and antiviral gene expression in individual infected cells. We coupled these measurements with conventional analyses to quantify delays in the HIV-1 replication cycle imposed by the biphasic nature of HIV-1 gene expression and by the assembly-inhibiting property of the matrix domain of Gag. We further related the dynamics of restriction factor (APOBEC3G) removal to the dynamics of HIV-1 replication in individual cells. These studies provide a timeline for key events in the HIV-1 replication cycle, and reveal that the interval between the onset of early and late HIV-1 gene expression is only ~3 h, but matrix causes a ~6-12 h delay in the generation of extracellular virions. Interestingly, matrix delays particle assembly to a time at which APOBEC3G has largely been removed from the cell. Thus, a need to prepare infected cells to be efficient producers of infectious HIV-1 may provide an impetus for programmed delays in HIV-1 virion genesis. Our findings also emphasize the significant heterogeneity in the length of the HIV-1 replication cycle in homogenous cell populations and suggest that a typical infected cell generates new virions for only a few hours at the end of a 48 h lifespan. Therefore, small changes in the lifespan of infected cells might have a large effect on viral yield in a single cycle and the overall clinical course in infected individuals.

Transthoracic Echocardiography-Guided Percutaneous Patent Ductus Arteriosus Occlusion: A New Strategy for Interventional Treatment.

INTRODUCTION: Percutaneous patent ductus arteriosus (PDA) occlusion has become the preferred therapeutic option, which uses fluoroscopy as the guidance. To reduce the x-ray exposure, PDA occlusion using the Amplatzer Duct Occluder II (ADO II) under guidance of transthoracic echocardiography only was conducted. This single center study aims to access the safety and efficiency of this new strategy. METHODS AND RESULTS: From June 2013 to May 2015, 63 consecutive PDA patients underwent transthoracic echocardiography-guided PDA occlusion through the femoral artery. Outpatient follow-up was conducted at 1, 3, and 6 months, and yearly. Sixty-two patients successfully underwent echocardiography-guided percutaneous PDA occlusion. One patient was converted to minimally invasive transthoracic occlusion due to failure of delivery sheath passage through tortuous PDA. Mean procedure duration was 24.3 ± 7.0 minutes; ADO II diameter averaged 4.6 ± 0.9 mm; 8 cases showed traces of residual shunt immediately after operation which resolved after 24 hours; and mean hospital stay was 3.4 ± 0.5 days. There was no occluder migration, hemolysis, pericardial effusion, pulmonary branch or aortic stenosis at mean 13.5 ± 4.8 months follow-up. CONCLUSIONS: This study demonstrated that percutaneous PDA occlusion can be successfully performed under guidance of transthoracic echocardiography only and appears safe and effective while avoiding radiation and contrast agent use.