Activating cryptic biosynthetic gene cluster through a CRISPR-Cas12a-mediated direct cloning approach.

Direct cloning of biosynthetic gene clusters (BGCs) from microbial genomes facilitates natural product-based drug discovery. Here, by combining Cas12a and the advanced features of bacterial artificial chromosome library construction, we developed a fast yet efficient in vitro platform for directly capturing large BGCs, named CAT-FISHING (CRISPR/Cas12a-mediated fast direct biosynthetic gene cluster cloning). As demonstrations, several large BGCs from different actinomycetal genomic DNA samples were efficiently captured by CAT-FISHING, the largest of which was 145 kb with 75% GC content. Furthermore, the directly cloned, 110 kb long, cryptic polyketide encoding BGC from Micromonospora sp. 181 was then heterologously expressed in a Streptomyces chassis. It turned out to be a new macrolactam compound, marinolactam A, which showed promising anticancer activity. Our results indicate that CAT-FISHING is a powerful method for complicated BGC cloning, and we believe that it would be an important asset to the entire community of natural product-based drug discovery.

A gene cluster encoding a nonribosomal peptide synthetase-like enzyme catalyzes γ-aromatic butenolides.

Sea cucumber-derived fungi have attracted much attention due to their capacity to produce an incredible variety of secondary metabolites. Genome-wide information on Aspergillus micronesiensis H39 obtained using third-generation sequencing technology (PacBio-SMRT) showed that the strain contains nonribosomal peptide synthetase (NRPS)-like gene clusters, which aroused our interest in mining its secondary metabolites. 11 known compounds (1-11), including two γ-aromatic butenolides (γ-AB) and five cytochalasans, were isolated from A. micronesiensis H39. The structures of the compounds were determined by NMR and ESIMS, and comparison with those reported in the literature. From the perspective of biogenetic origins, the γ-butyrolactone core of compounds 1 and 2 was assembled by NRPS-like enzyme. All of the obtained compounds showed no inhibitory activity against drug-resistant bacteria and fungi, as well as compounds 1 and 2 had no anti-angiogenic activity against zebrafish.

Risk Factors for Hospitalization Duration Longer Than 24 Hours Following Percutaneous Radiofrequency Ablation of Liver Tumours.

PURPOSE: Prior studies have described complications of radiofrequency ablation (RFA) of liver tumours. The aim of this study was to identify risk factors for hospitalization duration longer than 24 hours following RFA of liver tumours. METHODS: This retrospective, single-centre study included patients with liver tumours undergoing RFA between October 2017 and July 2020. Medical records were reviewed to collect patient, tumours, and procedure characteristics for each RFA session. The association between potential risk factors and duration of hospitalization (less than or more than 24 hours) was analyzed using univariate and multivariate logistic regressions. RESULTS: Our study included 291 patients (mean age: 65.2 ± 11.2 [standard deviation]; 201 men) undergoing 324 RFA sessions. Sixty-eight sessions (21.0%) resulted in hospitalization of more than 24 hours. Multivariate analysis identified each additional needle insertion per session (OR 1.4; 95% CI [1.1-1.9]; P = .02), RFA performed in segment V (OR 2.8; 95% CI [1.4-5.7]; P = .004), and use of artificial pneumothorax (OR 14.5; 95% CI [1.4-146.0]; P = .02) as potential risk factors. A history of hepatic encephalopathy (OR 2.6; 95% CI [1.1-6.0]; P = .03) was only significant in univariate analysis. Post-hoc, subgroup analysis of patients with hepatocellular carcinoma (69.8%) did not identify other risk factors. CONCLUSION: Risk factors for a hospitalization duration longer than 24 hours include a higher number of needle insertions per session, radiofrequency ablation in segment V, and use of an artificial pneumothorax.

[Characterization and identification of chemical constituents from Schizonepetae Spica based on UHPLC-Q-TOF-MS/MS technique].

The chemical constituents of Schizonepetae Spica were qualitatively analyzed by UHPLC-Q-TOF-MS/MS. An Agilent poroshell 120 SB-C_(18) column(3.0 mm×100 mm, 2.7 µm) was used for gradient elution with 0.1% formic acid water(A)-acetonitrile(B) solution as mobile phase at the flow rate of 0.4 mL·min~(-1) and column temperature of 45 ℃. The data were collected by scanning in positive and negative ion modes, and the compounds were identified by comparison of reference materials and PeakView software. Ninety-seven compounds were identified from Schizonepetae Spica, including 28 flavonoids, 23 phenolic acids, 23 fatty acids, 15 terpenoids, and 8 other compounds. The UHPLC-Q-TOF-MS/MS method established in this study can identify the chemical components of Schizonepetae Spica rapidly, accurately, and comprehensively, and provide a basis for the basic study of pharmacodynamic substances of Schizonepetae Spica.

Large aperture and defect-free liquid crystal planar optics enabled by high-throughput pulsed polarization patterning.

The liquid crystal (LC) geometrical phase optics, which is realized by the high-resolution control of the optical axis orientation in transparent micrometer-thin polymer films, is emerging as a next generation of planar optics. It features pronounced optical properties and stimuli-responsive behaviors, which could introduce appealing and new possibilities for photonic purposes. The development of fabrication techniques producing elements with large aperture sizes and arbitrarily varying molecular orientation is of significance in terms of practical utility. Here, we propose the pulsed polarization patterning technique to create large-aperture and defect-free LC geometrical phase elements. We investigated the capability of the azo photo-alignment material responding to nanosecond laser pulses and the corresponding anchoring behaviors to LCs. The threshold was reduced to one fourth of that under the continuous wave recording. The patterning resolution was found to be enhanced to around 0.71 µm, due to the ultra-fast interaction nature of the photo-alignment material with the polarized light field. We proposed the flying exposure mode to deliver high frequency modulated polarized laser pulses (8 kHz), with the precision stage moving in a uniform velocity for light-field stitching and the servo auto-focusing in the sample normal, enabling the stable and reliable polarization patterning for large aperture sizes. We further report on representative fabrication of LC polarization gratings with an aperture of 4 inch and 99.2% average diffraction efficiency.

Comparison of 18F-sodium fluoride positron emission tomography imaging and 99mTc-pyrophosphate in cardiac amyloidosis.

BACKGROUND: Pyrophosphate (PYP) scintigraphy provides high diagnostic accuracy for the detection of transthyretin (ATTR) cardiac amyloidosis (CA). There has recently been emerging interest in using 18F-sodium fluoride (NaF) for this application, yet its sensitivity has never been directly compared to that of PYP, the current molecular gold standard METHODS: Twelve subjects with ATTR-CA and 5 controls referred for PYP-SPECT were prospectively enrolled. 18F-NaF PET/CT scans were performed at 1 and 3 hours. Qualitative and quantitative analyses of the images were performed, and the sensitivity of 18F-NaF PET/CT and PYP-SPECT were compared RESULTS: Visual interpretation of NaF PET/CT yielded a sensitivity of 0.25 (95% CI 0.089 to 0.53) for the detection of ATTR-CA, which is significantly inferior to that of PYP-SPECT/CT (100%, P = .016). Visual interpretation at 3 hours yielded a similar sensitivity of 0.30 (95% CI 0.11 to 0.60, P = 1.00). There were no false-positive NaF PET studies. Mean target-to-background ratio (TBRmean) at 1h did not differ significantly (P = .21) in ATTR-CA subjects (0.83 ± 0.15) compared to controls (0.72 ± 0.15). Receiver operating characteristic (ROC) analysis yielded an area under the curve (AUC) of 0.69 ± 0.16 (95% CI 0.37 to 1.00, P = .23). CONCLUSION: With qualitative and quantitative analyses, sensitivity of NaF PET/CT is significantly inferior to that of PYP-SPECT for the diagnosis of ATTR-CA.

Monolayer 1T and 1T' MoSO as Promising Electrocatalyst for Hydrogen Evolution based on First Principle Calculations.

Molybdenum disulfide (MoS2 ) has been regarded as one of the most promising candidates for replacing Pt group noble metals as an efficient electrocatalyst to enhance the hydrogen evolution reaction (HER) in consideration of its relatively high earth abundance. Recent studies show that the catalytic efficiency of MoS2 for HER can be promoted by the presence of 1T-phase MoS2 . It is hard to precisely control the formation of 1T-MoS2 , however, due to its metastability relative to 2H-MoS2 . Elevating the stability of 1T phase allotrope is therefore of great importance and could be realized by replacing divalent S with monovalent elements or groups according to crystal field theory, which has been demonstrated through our first-principles density functional theory (DFT) calculation results. Differential Gibbs free energy analysis for hydrogen adsorption (ΔGH* ) suggest that 1T and 1T' MoSO (O doped MoS2 ) might be taken as potential candidate catalysts for HER process with better performance than 1T and 1T' MoS2 . We also propose a probable approach to synthesize 1T and 1T' MoSO under oxidation circumstance environment of graphene oxide.

Synthesis and Biological Evaluation of Celastrol Derivatives with Improved Cytotoxic Selectivity and Antitumor Activities.

Cdc37 associates kinase clients to Hsp90 and promotes the development of cancers. Celastrol, a natural friedelane triterpenoid, can disrupt the Hsp90-Cdc37 interaction to provide antitumor effects. In this study, 31 new celastrol derivatives, 2a-2d, 3a-3g, and 4a-4t, were designed and synthesized, and their Hsp90-Cdc37 disruption activities and antiproliferative activities against cancer cells were evaluated. Among these compounds, 4f, with the highest tumor cell selectivity (15.4-fold), potent Hsp90-Cdc37 disruption activity (IC50 = 1.9 µM), and antiproliferative activity against MDA-MB-231 cells (IC50 = 0.2 µM), was selected as the lead compound. Further studies demonstrated 4f has strong antitumor activities both in vitro and in vivo through disrupting the Hsp90-Cdc37 interaction and inhibiting angiogenesis. In addition, 4f exhibited less toxicity than celastrol and showed a good pharmacokinetics profile in vivo. These findings suggest that 4f may be a promising candidate for development of new cancer therapies.

Further delineation of the clinical spectrum of KAT6B disorders and allelic series of pathogenic variants.

PURPOSE: Genitopatellar syndrome and Say-Barber-Biesecker-Young-Simpson syndrome are caused by variants in the KAT6B gene and are part of a broad clinical spectrum called KAT6B disorders, whose variable expressivity is increasingly being recognized. METHODS: We herein present the phenotypes of 32 previously unreported individuals with a molecularly confirmed diagnosis of a KAT6B disorder, report 24 new pathogenic KAT6B variants, and review phenotypic information available on all published individuals with this condition. We also suggest a classification of clinical subtypes within the KAT6B disorder spectrum. RESULTS: We demonstrate that cerebral anomalies, optic nerve hypoplasia, neurobehavioral difficulties, and distal limb anomalies other than long thumbs and great toes, such as polydactyly, are more frequently observed than initially reported. Intestinal malrotation and its serious consequences can be present in affected individuals. Additionally, we identified four children with Pierre Robin sequence, four individuals who had increased nuchal translucency/cystic hygroma prenatally, and two fetuses with severe renal anomalies leading to renal failure. We also report an individual in which a pathogenic variant was inherited from a mildly affected parent. CONCLUSION: Our work provides a comprehensive review and expansion of the genotypic and phenotypic spectrum of KAT6B disorders that will assist clinicians in the assessment, counseling, and management of affected individuals.

Pure Inorganic Iodocuprate Framework Embedding In Situ Generated [Pb4(OH)4]4+ Cubic Template.

The cationic [Pb4(OH)4]4+ cubane as a template was first introduced to the 3D iodocuprate network, which is fabricated from the alternative connection of infinite [Cu2I2] n chains and µ2-I linkers. Distinct from most of the photocatalysts with UV or visible light for the photocatalytic degradation of an organic pollutant, the target compound could accomplish this task under direct sunlight because of the introduction of photoactive species. Our work provides a promising strategy to generate superior photocatalysts via the encapsulation of photoactive units into open frameworks.

Nonparametric response-adaptive randomization for continuous responses.

Many response-adaptive randomization procedures have been proposed and studied over the past few decades. However, most of these procedures are based on parametric structure and do not directly apply to nonparametric models. In this paper, we propose a response-adaptive randomization procedure based on Mann-Whitney U test statistic. Under widely satisfied conditions, we derive asymptotic properties of the randomization procedure and further obtain power functions in form under Mann-Whitney U test. Simulations show the proposed procedure is more robust and more ethical than classical response-adaptive randomization procedures in some circumstances. Advantages of the procedure are also illustrated in a redesigned real clinical trial.

Cloning and Functional Analysis of Phosphoethanolamine Methyltransferase Promoter from Maize (Zea mays L.).

Betaine, a non-toxic osmoprotectant, is believed to accumulate considerably in plants under stress conditions to maintain the osmotic pressure and promote a variety of processes involved in growth and development. Phosphoethanolamine N-methyltransferase (PEAMT), a key enzyme for betaine synthesis, is reported to be regulated by its upstream promoter. In the present investigation, by using the transgenic approach, a 1048 bp long promoter region of ZmPEAMT gene from Zea mays was cloned and functionally characterized in tobacco. Computational analysis affirmed the existence of abiotic stress responsive cis-elements like ABRE, MYC, HST, LST etc., as well as pathogen, wound and phytohormone responsive motifs. For transformation in tobacco, four 5'-deletion constructs of 826 bp (P2), 642 bp (P3), 428 bp (P4) and 245 bp (P5) were constructed from the 1048 bp (P1) promoter fragment. The transgenic plants generated through a single event exhibited a promising expression of GUS reporter protein in the leaf tissues of treated with salt, drought, oxidative and cold stress as well as control plants. The GUS expression level progressively reduced from P1 to P5 in the leaf tissues, whereas a maximal expression was observed with the P3 construct in the leaves of control plants. The expression of GUS was noted to be higher in the leaves of osmotically- or salt-treated transgenic plants than that in the untreated (control) plants. An effective expression of GUS in the transgenic plants manifests that this promoter can be employed for both stress-inducible and constitutive expression of gene(s). Due to this characteristic, this potential promoter can be effectively used for genetic engineering of several crops.

17q21 locus rs7216389 polymorphism and childhood asthma risk: a meta-analysis.

INTRODUCTION: Recently, a genome-wide association study (GWAS) indicated that rs7216389 polymorphism on chromosome 17q21 was associated with paediatric asthma risk. However, the results remained controversial. Therefore, a meta-analysis was performed. EVIDENCE ACQUISITION: A comprehensive literature retrieve was performed on PubMed, Embase and Science Direct databases up to Feb 20, 2016. The strength of association between 17q21 locus rs7216389 polymorphism and pediatric asthma risk was assessed by computing odds ratio (OR) with its corresponding 95% confidence interval (CI). EVIDENCE SYNTHESIS: A total of 10 studies with 7797 cases and 38757 controls were included. A statistically significant association of rs7216389 polymorphism and pediatric asthma risk was found (OR=1.41, 95%CI=1.34-1.49, P<0.00001). Furthermore, both Caucasians (OR=1.41, 95%CI=1.33-1.49, P<0.00001) and Asians (OR=1.43, 95%CI=1.25-1.63, P<0.00001) with rs7216389 polymorphism showed significant association, respectively. A significantly increased susceptibility was identified in atopic asthma (OR=1.45, 95%CI=1.22-1.72, P<0.00001). In the stratification analysis by study design, both case-control studies (OR=1.40, 95%CI=1.33-1.48, P<0.00001) and cohort studies (OR=2.05, 95%CI=1.32-3.17, P=0.001) showed significant association, respectively. CONCLUSIONS: In conclusion, this meta-analysis suggests that 17q21 locus rs7216389 polymorphism was significantly associated with paediatric asthma risk.

[Avermectins, intelligently made in China].

Avermectins, are pesticides of fermentation products with high efficacy and low toxicity and play important roles in food and agricultural product safety, animal and human health. Ivermectins, the derivatives of avermectins, are used to treat Onchocerciasis, also known as River Blindness. Thanks to these discoveries, more than 200 million Africans are lucky to be exempted from blindness. Great efforts have been made on better understanding of the microbial production system of avermectins through genetic engineering in China. Starting from scratch, Chinese avermectin industry has experienced a comprehensive technological innovation with significantly improved yield, titer and productivity of avermectins, and became the exclusive supplier for the global market. The success of avermectin industry innovation in China not only shed lights on the intelligent yield improvement of other microbial natural product drugs, but also gained wide international recognition. We provide here an overview of the discovery and development of basic and applied research of avermectins, especially historical evolution of avermectins made in China, which will benefit industrial development of microbial drugs in China.

[Progress in the application of neural oscillations cross-frequency coupling in cognitive function research].

Neural oscillations cross-frequency coupling (CFC) refers to the effect of the cross modulation between the electrophysiological oscillation rhythm in different ensembles of neurons. The CFC can reflect the mechanism of information transfer and exchange of local field potentials, electroencephalograph (EEG) and other neural electrophysiological activities at different spatial and temporal scales and plays an important role in the study of cognitive function. This paper introduces the basic phenomenon and classifications of neural oscillation CFC briefly, and reviews the typical applications in the study of the animal cognition model and human cognitive function in recent years, respectively. The main problems are also summarized and the future research is prospected in order to provide new ideas to promote the study and application of the CFC.

Synthesis, Crystal Structures, Molecular Docking and MAO-B Inhibitory Activity of Transition Metal Complexes Derived from 2-(4-(Pyridin-2-yl)piperazin-1-yl)acetic Acid.

Three new complexes derived from 2-(4-(pyridin-2-yl)piperazin-1-yl)acetic acid (HL), [M(L)2(H2O)2] where M = CuII (1), ZnII (2) and CdII (3), have been synthesized and characterized by IR spectroscopy, elemental analysis and X-ray crystallography. The inhibitory activity of these three complexes against MAO-B was tested in vitro, and the molecular docking experiments were also carried out to rationalize their binding models. Both the experimental and docking simulation results indicated that complex 1 has the best inhibitory activity with IC50 value being 6.5 ± 0.31 µM.

Long-term efficacy of implantable cardiac resynchronization therapy plus defibrillator for primary prevention of sudden cardiac death in patients with mild heart failure: an updated meta-analysis.

Previous studies of implantable cardiac resynchronization therapy plus defibrillator (CRT-D) therapy used for primary prevention of sudden cardiac death have suggested that CRT-D therapy is less effective in patients with mild heart failure and a wide QRS complex. However, the long-term benefits are variable. We performed a meta-analysis of randomized trials identified in systematic searches of MEDLINE, EMBASE, and the Cochrane Database. Three studies (3858 patients) with a mean follow-up of 66 months were included. Overall, CRT-D therapy was associated with significantly lower all-cause mortality than was implantable cardioverter defibrillator (ICD) therapy (OR, 0.78; 95 % CI, 0.63-0.96; P = 0.02; I (2) = 19 %). However, the risk of cardiac mortality was comparable between two groups (OR, 0.74; 95 % CI, 0.53-1.01; P = 0.06). CRT-D treatment was associated with a significantly lower risk of hospitalization for heart failure (OR, 0.67; 95 % CI, 0.50-0.89; P = 0.005; I (2) = 55 %). The composite outcome of all-cause mortality and hospitalization for heart failure was also markedly lower with CRT-D therapy than with ICD treatment alone (OR, 0.67; 95 % CI, 0.57-0.77; P < 0.0001; I (2) = 0 %). CRT-D therapy decreased the long-term risk of mortality and heart failure events in patients with mild heart failure with a wide QRS complex. However, long-term risk of cardiac mortality was similar between two groups. More randomized studies are needed to confirm these findings, especially in patients with NYHA class I heart failure or patients without LBBB.

Association between occupational stressors and type 2 diabetes among Chinese police officers: a 4-year follow-up study in Tianjin, China.

PURPOSE: To explore the relationship between occupational stressors and the incidence of type 2 diabetes mellitus among police officers. METHODS: Baseline data were collected from policemen who completed the Occupational Stress Inventory-Revised (OSI-R) questionnaire, a self-designed questionnaire, and underwent free clinical measurements at the Medical Center of Police Hospital in Tianjin, China, in April 2007. A total of 5811 policemen participated in follow-up with the dynamic observation of new-onset diabetes (NOD) events occurring annually between 2008 and 2011. Occupational stress was measured by the OSI-R questionnaire, which contains 14 different scales. Cox proportional hazards regression was used to calculate the hazard ratios (HR) of the incidence of type 2 diabetes mellitus (T2DM) by occupational stressors. RESULTS: A total of 3.1% of the participants (n = 179) developed NOD in the follow-up period from 2008 to 2011, and the incidence rates of NOD were 0.58% in 2008, 0.98% in 2009, 0.52% in 2010, and 1.01% in 2011. Role overload (RO), role boundary (RB), physical environment (PE), interpersonal strain (IS), and physical strain (PHS) were associated with the incidence of T2DM (RO: HR = 1.574, 95% CI = 1.071-2.372; RB: HR = 1.645, 95% CI = 1.144-2.365; PE: HR = 2.292, 95% CI = 1.545-3.400; IS: HR = 1.537, 95% CI = 1.079-2.191; and PHS: HR = 1.680, 95% CI = 1.167-2.006) after adjustment for confounding factors. A subgroup Cox regression analysis among traffic control police officers showed the specific work stressors remained robust except RO. CONCLUSIONS: Several aspects of stressors were independent predictors of T2DM in a prospective cohort study in Tianjin, China. This practical information can be applied to the development of psychological interventions against T2DM.

Bone marrow stromal cells transplantation combined with ultrashortwave therapy promotes functional recovery on spinal cord injury in rats.

OBJECTIVE: This study investigated the effects of bone marrow stromal cells (BMSCs) transplantation combined with low dose ultrashortwave (USW) radiation on functional recovery from spinal cord injury (SCI) in rats. Female Sprague-Dawley rats (n = 64) were randomly divided into five groups: sham-operated, as well as control, USW, BMSCs, and BMSCs + USW that were subjected to spinal cord contusion. BMSCs were transplanted into rats in the BMSCs and BMSCs+USW groups, while those in the USW and BMSCs + USW were exposed to radiation; Basso-Beattie-Bresnahan (BBB) tests were performed before the operation and at 1-week intervals after SCI for 7 weeks. 7 weeks later, animals were assessed footprint pattern, motor evoked potential (MEP), histological features, and expression of the ED1 and glial fibrillary acidic protein (GFAP), markers of activated macrophages and astrocytes, respectively, in the lesion area. BBB scores were higher in the BMSCs + USW than in the BMSCs and control groups. The USW and BMSCs + USW groups had improved coordination compared to the BMSCs and control groups (P < 0.01 and P < 0.001, respectively, vs. control). BMSCs + USW rats had a lower ratio of lesion/cavity to spinal cord area than the other injured rats, and also had expression of GFAP in transplanted BMSCs. All treatment groups had lower ED1 expression and MEP latency than the controls (P < 0.01 and P < 0.001, respectively). The results indicate that BMSCs transplantation combined with USW radiation is more effective than either treatment alone in promoting functional recovery after SCI, possibly due to concomitant suppression of inflammation and spinal cord repair.