An archaeal virus-encoded anti-CRISPR protein inhibits type III-B immunity by inhibiting Cas RNP complex turnover.

CRISPR-Cas systems are widespread in prokaryotes and provide adaptive immune against viral infection. Viruses encode a type of proteins called anti-CRISPR to evade the immunity. Here, we identify an archaeal virus-encoded anti-CRISPR protein, AcrIIIB2, that inhibits Type III-B immunity. We find that AcrIIIB2 inhibits Type III-B CRISPR-Cas immunity in vivo regardless of viral early or middle-/late-expressed genes to be targeted. We also demonstrate that AcrIIIB2 interacts with Cmr4α subunit, forming a complex with target RNA and Cmr-α ribonucleoprotein complex (RNP). Furtherly, we discover that AcrIIIB2 inhibits the RNase activity, ssDNase activity and cOA synthesis activity of Cmr-α RNP in vitro under a higher target RNA-to-Cmr-α RNP ratio and has no effect on Cmr-α activities at the target RNA-to-Cmr-α RNP ratio of 1. Our results suggest that once the target RNA is cleaved by Cmr-α RNP, AcrIIIB2 probably inhibits the disassociation of cleaved target RNA, therefore blocking the access of other target RNA substrates. Together, our findings highlight the multiple functions of a novel anti-CRISPR protein on inhibition of the most complicated CRISPR-Cas system targeting the genes involved in the whole life cycle of viruses.

Electrochemiluminescence Distance and Reactivity of Coreactants Determine the Sensitivity of Bead-Based Immunoassays.

Herein we report the study of electrochemiluminescence (ECL) generation by tris(2,2'-bipyridyl)ruthenium (Ru(bpy)3 2+ ) and five tertiary amine coreactants. The ECL distance and lifetime of coreactant radical cations were measured by ECL self-interference spectroscopy. And the reactivity of coreactants was quantitatively evaluated in terms of integrated ECL intensity. By statistical analysis of ECL images of single Ru(bpy)3 2+ -labeled microbeads, we propose that ECL distance and reactivity of coreactant codetermine the emission intensity and thus the sensitivity of immunoassay. 2,2-bis(hydroxymethyl)-2,2',2''-nitrilotriethanol (BIS-TRIS) can well balance ECL distance-reactivity trade-off and enhance the sensitivity by 236 % compared with tri-n-propylamine (TPrA) in the bead-based immunoassay of carcinoembryonic antigen. The study brings an insightful understanding of ECL generation in bead-based immunoassay and a way of maximizing the analytical sensitivity from the aspect of coreactant.

A CRISPR-associated factor Csa3a regulates DNA damage repair in Crenarchaeon Sulfolobus islandicus.

CRISPR-Cas system provides acquired immunity against invasive genetic elements in prokaryotes. In both bacteria and archaea, transcriptional factors play important roles in regulation of CRISPR adaptation and interference. In the model Crenarchaeon Sulfolobus islandicus, a CRISPR-associated factor Csa3a triggers CRISPR adaptation and activates CRISPR RNA transcription for the immunity. However, regulation of DNA repair systems for repairing the genomic DNA damages caused by the CRISPR self-immunity is less understood. Here, according to the transcriptome and reporter gene data, we found that deletion of the csa3a gene down-regulated the DNA damage response (DDR) genes, including the ups and ced genes. Furthermore, in vitro analyses demonstrated that Csa3a specifically bound the DDR gene promoters. Microscopic analysis showed that deletion of csa3a significantly inhibited DNA damage-induced cell aggregation. Moreover, the flow cytometry study and survival rate analysis revealed that the csa3a deletion strain was more sensitive to the DNA-damaging reagent. Importantly, CRISPR self-targeting and DNA transfer experiments revealed that Csa3a was involved in regulating Ups- and Ced-mediated repair of CRISPR-damaged host genomic DNA. These results explain the interplay between Csa3a functions in activating CRISPR adaptation and DNA repair systems, and expands our understanding of the lost link between CRISPR self-immunity and genome stability.

DNA Motifs and an Accessory CRISPR Factor Determine Cas1 Binding and Integration Activity in Sulfolobus islandicus.

CRISPR-Cas systems empower prokaryotes with adaptive immunity against invasive mobile genetic elements. At the first step of CRISPR immunity adaptation, short DNA fragments from the invaders are integrated into CRISPR arrays at the leader-proximal end. To date, the mechanism of recognition of the leader-proximal end remains largely unknown. Here, in the Sulfolobus islandicus subtype I-A system, we show that mutations destroying the proximal region reduce CRISPR adaptation in vivo. We identify that a stem-loop structure is present on the leader-proximal end, and we demonstrate that Cas1 preferentially binds the stem-loop structure in vitro. Moreover, we demonstrate that the integrase activity of Cas1 is modulated by interacting with a CRISPR-associated factor Csa3a. When translocated to the CRISPR array, the Csa3a-Cas1 complex is separated by Csa3a binding to the leader-distal motif and Cas1 binding to the leader-proximal end. Mutation at the leader-distal motif reduces CRISPR adaptation efficiency, further confirming the in vivo function of leader-distal motif. Together, our results suggest a general model for binding of Cas1 protein to a leader motif and modulation of integrase activity by an accessory factor.

Thermally stable monolithic Doppler asymmetric spatial heterodyne interferometer: optical design and laboratory performance.

We report on a thermally stable monolithic Doppler asymmetric spatial heterodyne (DASH) interferometer with field-widening prisms for thermospheric wind measurements by observing the Doppler shift of the airglow emission. Analytical deduction and numerical simulation are applied to determine the central optical path difference, the thermal compensation condition and the field-widening design. A monolithic interferometer with optimized configuration was built and tested in the laboratory. Laboratory tests show that the best visibility of 0.94 was realized with the 9 ° field-of-view illumination, while the thermal responses of the spatial frequency and the optical phase offset are 0.0154 cm-1/°C and 0.469 rad/°C, respectively.

Analysis and correction of distortions in a spatial heterodyne spectrometer system.

In this paper a method for correcting the radial distortion of interferograms generated by a spatial heterodyne spectrometer system is presented. Instead of utilizing calibration patterns, the distortion model parameters are estimated based on the distorted fringe features generated by projecting the straight interference stripes onto the detector. Comparisons between polynomial models and division models indicate that division models can deliver competitive performance on the reconstructed image with fewer parameters. Simulated interferograms based on ray-tracing are used to demonstrate the correction of errors in the spatial, phase, and spectral domain caused by optical distortion.

Effective wind and temperature retrieval from Doppler asymmetric spatial heterodyne spectrometer interferograms.

This paper presents a method for wind velocity and Doppler temperature retrieval from interferograms of a Doppler asymmetric spatial heterodyne spectrometer. This method is based on the analytic representation of the signal and the subsequent algorithms. It turns out to be more robust than the conventional Fourier transform method at low SNR. The influence of optical dispersion on the accuracy of the retrieved parameters is also characterized. The effective optical path difference is suggested for use in wind and temperature retrieval routines. Computer simulations are used to characterize the accuracy of the proposed method, in particular regarding the influence of optical dispersion.

ADRB2 polymorphisms and dyslipidemia risk in Chinese hypertensive patients.

Single nucleotide polymorphisms (SNPs) within a ß-adrenergic receptor (ADRB2) were shown to be related to lipid traits or hyperlipidemia in different ethnicities, but not in a Chinese population. We performed the present study to investigate the possible relationship between them in a Chinese hypertensive population. Seven hundred and eighty-three hypertensive subjects were enrolled in the hospital-based retrospective research. Using the TaqMan PCR method, three polymorphisms (C-47T, A46G, and C79G) of ADRB2 were detected. For the whole population, no significant statistical difference was found for all serum lipids. Similar findings were seen in men and women subgroups. Subsequently, in the case-control study, we observed that the A46G polymorphism was significantly associated with the elevated risk of hypertriglyceridemia in the dominant model (OR: 1.47, 95%CI: 1.05-2.06, P = 0.025). There are no significant differences in the other four models. With regard to C79G and C-47T, no significant association was seen in this population. In addition, haplotype analysis showed that the TAC haplotype carrying frequent alleles of the three SNPs played a reduced role in hypertriglyceridemia risk and the TGC haplotype carrying rare allele of A46G expressed a significant risk effect. In conclusion, these findings indicated that the ADRB2 SNPs might be a genetic risk factor for dyslipidemia in the Chinese hypertensive patients.

Association of the bradykinin receptors genes variants with hypertension: a case-control study and meta-analysis.

BACKGROUND: The present study was to investigate the role of bradykinin receptors genes polymorphisms on hypertension risk in Northern Han Chinese population. We also carried out a meta-analysis on Chinese to derive a more full assessment of this association. METHODS AND RESULTS: A total of 976 subjects from Northern Han Chinese and 7 studies with 1599 cases and 1425 controls were included in this case-control study and in the current meta-analysis, respectively. For the case-control study, we identified the genotypes of -58T/C and 1098A/G polymorphism in BDKRB2 and BDKRB1 genes, respectively, by TaqMan PCR method. Overall, we found significant association between the -58T/C polymorphism and the increased risk of hypertension in the allele comparison (p = 0.01, OR = 1.386, 95% CI [1.138-1.688]). Subgroup analysis by gender suggested that this obvious association could still be found in males, but not in females. For the 1098A/G polymorphism, no significant association was revealed in overall and subgroup analysis. For the meta-analysis involving the -58T/C polymorphism, a significant association between this polymorphism and hypertension was observed in the whole group. In Chinese Han subgroup, we found significant association with hypertension in allele comparison(C vs. T: p = 0.03, OR = 1.28, 95% CI 1.03-1.59, pheterogeneity = 0.05). CONCLUSIONS: Our case-control study indicated that -58T/C might be significantly associated with the increased risk of hypertension in Northern Han Chinese population, which was partially confirmed by our meta-analysis.

Repeat interruptions in spinocerebellar ataxia type 10 expansions are strongly associated with epileptic seizures.

Spinocerebellar ataxia type 10 (SCA10), an autosomal dominant neurodegenerative disorder, is the result of a non-coding, pentanucleotide repeat expansion within intron 9 of the Ataxin 10 gene. SCA10 patients present with pure cerebellar ataxia; yet, some families also have a high incidence of epilepsy. SCA10 expansions containing penta- and heptanucleotide interruption motifs, termed "ATCCT interruptions," experience large contractions during germline transmission, particularly in paternal lineages. At the same time, these alleles confer an earlier age at onset which contradicts traditional rules of genetic anticipation in repeat expansions. Previously, ATCCT interruptions have been associated with a higher prevalence of epileptic seizures in one Mexican-American SCA10 family. In a large cohort of SCA10 families, we analyzed whether ATCCT interruptions confer a greater risk for developing seizures in these families. Notably, we find that the presence of repeat interruptions within the SCA10 expansion confers a 6.3-fold increase in the risk of an SCA10 patient developing epilepsy (6.2-fold when considering patients of Mexican ancestry only) and a 13.7-fold increase in having a positive family history of epilepsy (10.5-fold when considering patients of Mexican ancestry only). We conclude that the presence of repeat interruptions in SCA10 repeat expansion indicates a significant risk for the epilepsy phenotype and should be considered during genetic counseling.

3D LIDAR-camera extrinsic calibration using an arbitrary trihedron.

This paper presents a novel way to address the extrinsic calibration problem for a system composed of a 3D LIDAR and a camera. The relative transformation between the two sensors is calibrated via a nonlinear least squares (NLS) problem, which is formulated in terms of the geometric constraints associated with a trihedral object. Precise initial estimates of NLS are obtained by dividing it into two sub-problems that are solved individually. With the precise initializations, the calibration parameters are further refined by iteratively optimizing the NLS problem. The algorithm is validated on both simulated and real data, as well as a 3D reconstruction application. Moreover, since the trihedral target used for calibration can be either orthogonal or not, it is very often present in structured environments, making the calibration convenient.

Integration of Cobalt Phthalocyanine, Acetylene Black and Cu2 O Nanocubes for Efficient Electroreduction of CO2 to C2 H4.

Suppressing side reactions and simultaneously enriching key intermediates during CO2 reduction reaction (CO2 RR) has been a challenge. Here, we propose a tandem catalyst (Cu2 O NCs-C-Copc) consisting of acetylene black, cobalt phthalocyanine (Copc) and cuprous oxide nanocubes (Cu2 O NCs) for efficient CO2 -to-ethylene conversion. Density-functional theory (DFT) calculation combined with experimental verification demonstrated that Copc can provide abundant CO to nearby copper sites while acetylene black successfully reduces the formation energies of key intermediates, leading to enhanced C2 H4 selectivity. X-ray photoelectron spectroscopy (XPS) and potentiostatic tests indicated that the catalytic stability of Cu2 O NCs-C-Copc was significantly enhanced compared with Cu2 O NCs. Finally, the industrial application prospect of the catalyst was evaluated using gas diffusion electrolyzers. The F E C 2 H 4 ${{\rm { F}}{{\rm { E}}}_{{{\rm { C}}}_{{\rm { 2}}}{{\rm { H}}}_{{\rm { 4}}}}}$ of Cu2 O NCs-C-Copc can reach to 58.4 % at -1.1 V vs. RHE in 0.1 M KHCO3 and 70.3 % at -0.76 V vs. RHE in 1.0 M KOH. This study sheds new light on the design and development of highly efficient CO2 RR tandem catalytic systems.

Cu2O Nanoparticles Wrapped by N-Doped Carbon Nanotubes for Efficient Electroreduction of CO2 to C2 Products.

Electroreduction of carbon dioxide (CO2) to C2 products (ethylene and ethanol) using efficient catalysts is a feasible approach to alleviate the climate crisis. Cuprous oxide nanoparticles (Cu2O NPs) are a promising catalyst for C2 production but suffer from inherent selectivity and durability. To address this challenge, a Cu2O NPs-nitrogen-doped carbon nanotube (Cu2O NPs-NCNT) composite was prepared with carbon nanotubes (CNTs), Cu2O NPs, and phthalocyanine (Pc). The results indicate that Cu2O NPs-NCNT has excellent Faradic efficiency of C2 products (77.61%) at -1.1 V vs RHE, which is 103.43% higher than that of Cu2O NPs. In the potentiostatic electrolysis combined with Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements, Cu2O NPs-NCNT exhibited structural and catalytic current stability over 10 h. Finally, density functional theory calculations combined with XPS demonstrated that the NCNT in Cu2O NPs-NCNT can selectively absorb CO2 through specific N-CO2 interactions. Our work provides a unique strategy to promote the selectivity of Cu2O NPs for C2 production by introducing N-doped linear carbon materials to fabricate composite.

Aqueous microdroplets promote C-C bond formation and sequences in the reverse tricarboxylic acid cycle.

The reverse tricarboxylic acid cycle (rTCA) is a central anabolic network that uses carbon dioxide (CO2) and may have provided complex carbon substrates for life before the advent of RNA or enzymes. However, non-enzymatic promotion of the rTCA cycle, in particular carbon fixation, remains challenging, even with primordial metal catalysis. Here, we report that the fixation of CO2 by reductive carboxylation of succinate and α-ketoglutarate was achieved in aqueous microdroplets under ambient conditions without the use of catalysts. Under identical conditions, the aqueous microdroplets also facilitated the sequences in the rTCA cycle, including reduction, hydration, dehydration and retro-aldol cleavage and linked with the glyoxylate cycle. These reactions of the rTCA cycle were compatible with the aqueous microdroplets, as demonstrated with two-reaction and four-reaction sequences. A higher selectivity giving higher product yields was also observed. Our results suggest that the microdroplets provide an energetically favourable microenvironment and facilitate a non-enzymatic version of the rTCA cycle in prebiotic carbon anabolism.

Olfactory impairment in familial ataxias.

The main clinical manifestations of the spinocerebellar ataxias (SCAs) result from the involvement of the cerebellum and its connections. Cerebellar activity has been consistently observed in functional imaging studies of olfaction, but the anatomical pathways responsible for this connection have not yet been elucidated. Previous studies have demonstrated olfactory deficit in SCA2, Friedreich's ataxia and in small groups of ataxia of diverse aetiology. The authors used a validated version of the 16-item smell identification test from Sniffin' Sticks (SS-16) was used to evaluate 37 patients with genetically determined autosomal dominant ataxia, and 31 with familial ataxia of unknown genetic basis. This data was also compared with results in 106 Parkinson's disease patients and 218 healthy controls. The SS-16 score was significantly lower in ataxia than in the control group (p<0.001, 95% CI for ß=0.55 to 1.90) and significantly higher in ataxia than in Parkinson's disease (p<0.001, 95% CI for ß=-4.58 to -3.00) when adjusted for age (p=0.001, 95% CI for ß=-0.05 to -0.01), gender (p=0.19) and history of tobacco use (p=0.41). When adjusted for general cognitive function, no significant difference was found between the ataxia and control groups. This study confirms previous findings of mild hyposmia in ataxia, and further suggests this may be due to general cognitive deficits rather than specific olfactory problems.

Early Age Shrinkage and Mechanical Effect of Ultra-High-Performance Concrete Composite Deck: A Case Study with In Situ Test and Numerical Simulation.

For the Honghe Bridge project located in Yunnan Province, Southwest China, a steel/ultrahigh-performance concrete (UHPC) composite deck is used in the suspension bridge with a 700 m main span, and the steel stud connectors are used in the 50 mm-thick UHPC layer. To investigate the shrinkage behavior of UHPC and the relevant influence, the in situ time-dependent strain is measured continuously, and within the 20-day curing time, the material behavior is summarized based on test results. This paper proposes a prediction model for UHPC shrinkage which is refined from the widely used B3 model for normal concrete material, and the parameter values are modified and optimized by experimental comparison. Combining the numerical model and the finite element analysis model of the composite deck, the detailed mechanical state in structural parts is studied. For the practical construction, the simulation results indicate that the small thickness of UHPC above the stud and weak bond strength can influence the eventual structural performance greatly. In the discussion of stress distribution at different locations of the deck, the potential crack on the edge and the corner of the UHPC-steel interface and the mechanical damage on the stud connector around are also indicated.

Effect of the Flame Retardants and Glass Fiber on the Polyamide 66/Polyphenylene Oxide Composites.

In this work, polyamide 66/polyphenylene oxide (PA66/PPO) composites, including the flame retardants 98 wt% aluminum diethylphosphinate + 2 wt% polydimethylsiloxane (P@Si), Al(OH)3-coated red phosphorus (RP*), and glass fiber (GF), were systematically studied, respectively. The limiting oxygen index (LOI), UL-94 vertical burning level, and thermal and mechanical properties of the PA66/PPO composites were characterized. The results showed that the P@Si and RP flame retardants both improved the LOI value and UL-94 vertical burning level of the PA66/PPO composites, and PA66/PPO composites passed to the UL-94 V-0 level when the contents of P@Si and RP* flame retardants were 16 wt% and 8 wt%. On the other hand, the mechanical properties of the PA66/PPO composites were reduced from a ductile to a brittle fracture mode. The addition of GF effectively made up for these defects and improved the mechanical properties of the PA66/PPO composites containing the P@Si and RP*, but it did not change the fracture mode. P@Si and RP* flame retardants improved the thermal decomposition of PA66/PPO/GF composites and reduced the maximum mass loss rates, showing that the PA66/PPO/GF composites containing the P@Si and RP* flame retardants could be used in higher-temperature fields.

Mass spectrometric observation on free radicals during electrooxidation of dopamine.

It has been challenging to directly observe the o-semiquinone radicals and transient intermediates produced during the oxidation of dopamine (DA). To achieve this goal, we developed an electrochemistry-neutral reionization-mass spectrometry (EC-NR-MS) technique for online studying the electrooxidation process of DA. The EC-NR device mainly composed by a self-designed EC flow cell, a sonic spray ionization source, a heating tube, an ion deflector and an electrospray ionization source. By precisely controlling the oxidation potential at 0.55 V, a series of reaction products include o-quinone (DAQ), Leukodopaminochrome (LDAC), Dopaminochrome (DAC), 5,6-dihydroxyindole (DHI) and DA dimer clearly appeared in the MS spectrum. Based on the ion deflector of EC-NR setup, the neutral o-semiquinone radical DA● and neutral Leukodopaminochrome radical LDAC● were successfully extracted from these ionic products and allowed to be detected by MS. Such finding was further confirmed by spin trapping experiment. The formation of o-semiquinone radical anion (DA●-) has been identified as its metal complex with Zn2+. These results provide conclusive evidence for the DA oxidation mechanism, which consists of proton coupled electron transfer and sequential proton-electron transfer steps.

Development and Optimization of a Prognostic Model Associated with Stemness Genes in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is one of the most lethal cancers worldwide, which is associated with a variety of risk factors. Cancer stem cells are self-renewal cells, which can promote the occurrence and metastasis of tumors and enhance the drug resistance of tumor treatment. This study aimed to develop a stemness score model to assess the prognosis of hepatocellular carcinoma (HCC) patients for the optimization of treatment. The single-cell sequencing data GSE149614 was downloaded from the GEO database. Then, we compared the gene expression of hepatic stem cells and other hepatocytes in tumor samples to screen differentially expressed genes related to stemness. R package "clusterProfiler" was used to explore the potential function of stemness-related genes. We then constructed a prognostic model using LASSO regression analysis based on the TCGA and GSE14520 cohorts. The associations of stemness score with clinical features, drug sensitivity, gene mutation, and tumor immune microenvironment were further explored. R package "rms" was used to construct the nomogram model. A total of 18 stemness-related genes were enrolled to construct the prognosis model. Kaplan-Meier analysis proved the good performance of the stemness score model at predicting overall survival (OS) of HCC patients. The stemness score was closely associated with clinical features, drug sensitivity, and tumor immune microenvironment of HCC. The infiltration level of CD8+ T cells was lower, and tumor-associated macrophages were higher in patients with high-stemness score, indicating an immunosuppressive microenvironment. Our study established an 18 stemness-related gene model that reliably predicts OS in HCC. The findings may help clarify the biological characteristics and progression of HCC and help the future diagnosis and therapy of HCC.

Mass spectrometric detection of fleeting neutral intermediates generated in electrochemical reactions.

Towards the goal of on-line monitoring of transient neutral intermediates during electrochemical reactions, an electrochemistry-neutral reionization-mass spectrometry (EC-NR-MS) technique was developed in this work. The EC-NR setup consisted of a customized EC flow cell, a sonic spray ionization source, a heating tube, an ion deflector and an electrospray ionization source, which were respectively used for the precise control of the electrochemical reaction, solution nebulization, droplet desolvation, ion deflection and neutral intermediate ionization. Based on the EC-NR-MS approach, some long-sought neutral radicals including TPrA˙, DBAE˙ and TEOA˙, which belong to important reductive intermediates in electrochemiluminescence (ECL) reactions, were successfully identified which helps to clarify the previously unproven ECL reaction mechanism. These findings were also supported by spin-trapping experiments and the tandem MS technique. Accordingly, the EC-NR-MS method provides a direct solution for studying complicated electrochemical reactions, especially for detecting short-lived neutral radicals as well as ionic intermediates.