Lysine acetylation regulates the AT-rich DNA possession ability of H-NS.

H-NS, the histone-like nucleoid-structuring protein in bacteria, regulates the stability of the bacterial genome by inhibiting the transcription of horizontally transferred genes, such as the type III and type VI secretion systems (T3/T6SS). While eukaryotic histone posttranslational modifications (PTMs) have been extensively studied, little is known about prokaryotic H-NS PTMs. Here, we report that the acetylation of H-NS attenuates its ability to silence horizontally transferred genes in response to amino acid nutrition and immune metabolites. Moreover, LC-MS/MS profiling showed that the acetyllysine sites of H-NS and K120 are indispensable for its DNA-binding ability. Acetylation of K120 leads to a low binding affinity for DNA and enhances T3/T6SS expression. Furthermore, acetylation of K120 impairs the AT-rich DNA recognition ability of H-NS. In addition, lysine acetylation in H-NS modulates in vivo bacterial virulence. These findings reveal the mechanism underlying H-NS PTMs and propose a novel mechanism by which bacteria counteract the xenogeneic silencing of H-NS.

Global, Regional, and National Burdens of Stroke in Children and Adolescents From 1990 to 2019: A Population-Based Study.

BACKGROUND: Stroke is one of the leading causes of death among children, yet evidence on stroke incidence and prognosis in this population is largely neglected worldwide. The aim of this study was to estimate the latest burden of childhood stroke, as well as trends, risk factors, and inequalities from 1990 to 2019, at the global, regional, and national levels. METHODS: The Global Burden of Disease 2019 study was utilized to evaluate the prevalence, incidence, years lived with disability, years of life lost (YLLs), and average annual percentage changes in stroke among populations aged 0 to 19 years from 1990 to 2019. RESULTS: The global age-standardized incidence of stroke increased (average annual percentage change, 0.15% [95% uncertainty interval, 0.09%-0.21%]), while YLLs decreased substantially (average annual percentage change, -3.33% [95% uncertainty interval, -3.38% to -3.28%]) among children and adolescents between 1990 and 2019. Ischemic stroke accounted for 70% of incident cases, and intracerebral hemorrhage accounted for 63% of YLLs. Children under 5 years of age had the highest incidence of ischemic stroke, while adolescents aged 15 to 19 years had the highest incidence of hemorrhagic stroke. In 2019, low-income and middle-income countries were responsible for 84% of incident cases and 93% of YLLs due to childhood stroke. High-sociodemographic index countries had a reduction in YLLs due to stroke that was more than twice as fast as that of low-income and middle-income. CONCLUSIONS: Globally, the burden of childhood stroke continues to increase, especially among females, children aged <5 years, and low-sociodemographic index countries, such as sub-Saharan Africa. The burden of childhood stroke is likely undergoing a significant transition from being fatal to causing disability. Global public health policies and the deployment of health resources need to respond rapidly and actively to this shift.

Fluorinated 1,7-DO2A-Based Iron(II) Complexes as Sensitive 19F MRI Molecular Probes for Visualizing Renal Dysfunction in Living Mice.

Kidney diseases have become an important global health concern due to their high incidence, inefficient diagnosis, and poor prognosis. Devising direct methods, especially imaging means, to assess renal function is the key for better understanding the mechanisms of various kidney diseases and subsequent development of effective treatment. Herein, we developed a fluorinated ferrous chelate-based sensitive probe, 1,7-DO2A-Fe(II)-F18 (Probe 1), for 19F magnetic resonance imaging (MRI). This highly fluorinated probe (containing 18 chemically equivalent 19F atoms with a fluorine content at 35 wt %) achieves a 15-time enhancement in signal intensity compared with the fluorine-containing ligand alone due to the appropriately regulated 19F relaxation times by the ferrous ion, which significantly increases imaging sensitivity and reduces acquisition time. Owing to its high aqueous solubility, biostability, and biocompatibility, this probe could be rapidly cleared by kidneys, which provides a means for monitoring renal dysfunction via 19F MRI. With this probe, we accomplish in vivo imaging of the impaired renal dysfunction caused by various kidney diseases including acute kidney injury, unilateral ureteral obstruction, and renal fibrosis at different stages. Our study illustrates the promising potential of Probe 1 for in vivo real-time visualization of kidney dysfunction, which is beneficial for the study, diagnosis, and even stratification of different kidney diseases. Furthermore, the design strategy of our probe is inspiring for the development of more high-performance 19F MRI probes for monitoring various biological processes.

Xenogeneic nucleoid-associated EnrR thwarts H-NS silencing of bacterial virulence with unique DNA binding.

Type III and type VI secretion systems (T3/T6SS) are encoded in horizontally acquired genomic islands (GIs) that play crucial roles in evolution and virulence in bacterial pathogens. T3/T6SS expression is subjected to tight control by the host xenogeneic silencer H-NS, but how this mechanism is counteracted remains to be illuminated. Here, we report that xenogeneic nucleoid-associated protein EnrR encoded in a GI is essential for virulence in pathogenic bacteria Edwardsiella and Salmonella. We showed that EnrR plays critical roles in T3/T6SS expression in these bacteria. Various biochemical and genetic analyses demonstrated that EnrR binds and derepresses the promoter of esrB, the critical regulator of T3/T6SS, to promote their expression by competing with H-NS. Additionally, EnrR targets AT-rich regions, globally modulates the expression of ∼363 genes and is involved in various cellular processes. Crystal structures of EnrR in complex with a specific AT-rich palindromic DNA revealed a new DNA-binding mode that involves conserved HTH-mediated interactions with the major groove and contacts of its N-terminal extension to the minor groove in the symmetry-related duplex. Collectively, these data demonstrate that EnrR is a virulence activator that can antagonize H-NS, highlighting a unique mechanism by which bacterial xenogeneic regulators recognize and regulate foreign DNA.

Advancing Precision in 3D Echocardiography: Incorporating 3D Markers to Aid Spatial Orientation.

The incorporation of 3D imaging into diagnostic and interventional echocardiography has rapidly expanded in recent years. Applications such as multiplanar reconstruction that were once considered research tools and required off-cart analysis can now readily be performed at the point of image acquisition and in real-time during live image acquisition for procedural guidance. While the application and quality of 3D images have significantly improved in recent years, there remains a noticeable lag in the evolution of artificial intelligence that would further simplify the interpretative processes, both during live sessions and offline analyses. Users are still required to mentally reconstruct sliced images during multiplanar reconstruction based on color-coded planes. While this may be an effortless task for the seasoned echocardiographer, it can be a challenging task for echocardiographers who are less familiar with 3D imaging and multiplanar reconstruction. This article describes the utility of using 3D markers to aid in image interpretation.

Misidentification of the True Aortic Annulus With 2-dimensional Echocardiography: A Critical Appraisal Using 3-Dimensional Imaging.

OBJECTIVES: This study aimed to evaluate the accuracy of identifying the true aortic valve (AV) annulus using 2-dimensional (2D) echocardiography, with the goal of highlighting potential misidentification issues in clinical practice. DESIGN: An observational study employing 3-dimensional (3D) datasets to generate 2D images of the AV annulus for analysis. SETTING: The study was conducted in an academic medical center. PARTICIPANTS: Three-dimensional transesophageal echocardiography datasets were obtained from 11 patients with normal AV and aortic root anatomies undergoing coronary artery bypass surgery. Attending anesthesiologists certified by the National Board of Echocardiography (NBE) were approached subsequently to participate in this study. INTERVENTIONS: Two images per patient were generated from 3D datasets, reflecting the mid-esophageal long-axis view of the AV, a true AV annulus image, and an off-axis image. A survey was distributed to NBE-certified perioperative echocardiographers across 12 academic institutions to identify the true AV annulus from these images. MEASUREMENTS AND MAIN RESULTS: The survey, completed by 45 qualified respondents, revealed a significant misidentification rate of the true AV annulus, with only 36.8% of responses correctly identifying it. The rate of correct identification varied across image sets, with 44.4% of participants unable to correctly identify any true AV annulus image. CONCLUSIONS: The study highlighted the limitations of 2D echocardiography in accurately identifying the true AV annulus in complex 3D structures like the aortic root. The findings suggest a need for greater reliance on advanced imaging modalities, such as 3D echocardiography, to improve accuracy in clinical practice.

Artificial Intelligence for Anesthesiology Board-Style Examination Questions: Role of Large Language Models.

New artificial intelligence tools have been developed that have implications for medical usage. Large language models (LLMs), such as the widely used ChatGPT developed by OpenAI, have not been explored in the context of anesthesiology education. Understanding the reliability of various publicly available LLMs for medical specialties could offer insight into their understanding of the physiology, pharmacology, and practical applications of anesthesiology. An exploratory prospective review was conducted using 3 commercially available LLMs--OpenAI's ChatGPT GPT-3.5 version (GPT-3.5), OpenAI's ChatGPT GPT-4 (GPT-4), and Google's Bard--on questions from a widely used anesthesia board examination review book. Of the 884 eligible questions, the overall correct answer rates were 47.9% for GPT-3.5, 69.4% for GPT-4, and 45.2% for Bard. GPT-4 exhibited significantly higher performance than both GPT-3.5 and Bard (p = 0.001 and p < 0.001, respectively). None of the LLMs met the criteria required to secure American Board of Anesthesiology certification, according to the 70% passing score approximation. GPT-4 significantly outperformed GPT-3.5 and Bard in terms of overall performance, but lacked consistency in providing explanations that aligned with scientific and medical consensus. Although GPT-4 shows promise, current LLMs are not sufficiently advanced to answer anesthesiology board examination questions with passing success. Further iterations and domain-specific training may enhance their utility in medical education.

zPoseScore model for accurate and robust protein-ligand docking pose scoring in CASP15.

We introduce a deep learning-based ligand pose scoring model called zPoseScore for predicting protein-ligand complexes in the 15th Critical Assessment of Protein Structure Prediction (CASP15). Our contributions are threefold: first, we generate six training and evaluation data sets by employing advanced data augmentation and sampling methods. Second, we redesign the "zFormer" module, inspired by AlphaFold2's Evoformer, to efficiently describe protein-ligand interactions. This module enables the extraction of protein-ligand paired features that lead to accurate predictions. Finally, we develop the zPoseScore framework with zFormer for scoring and ranking ligand poses, allowing for atomic-level protein-ligand feature encoding and fusion to output refined ligand poses and ligand per-atom deviations. Our results demonstrate excellent performance on various testing data sets, achieving Pearson's correlation R = 0.783 and 0.659 for ranking docking decoys generated based on experimental and predicted protein structures of CASF-2016 protein-ligand complexes. Additionally, we obtain an averaged local distance difference test (lDDT pli = 0.558) of AIchemy LIG2 in CASP15 for de novo protein-ligand complex structure predictions. Detailed analysis shows that accurate ligand binding site prediction and side-chain orientation are crucial for achieving better prediction performance. Our proposed model is one of the most accurate protein-ligand pose prediction models and could serve as a valuable tool in small molecule drug discovery.

Geological events and climate change drive diversification and speciation of mute cicadas in eastern continental Asia.

The poor mobility of nymphs living underground, usually for many years, and the weak flying ability of adults make cicadas unique for evolutionary biology and bio-geographical study. Cicadas of the genus Karenia are unusual in Cicadidae in lacking the timbals that produce sound. Population differentiation, genetic structure, dispersal and evolutionary history of the eastern Asian mute cicada Karenia caelatata were investigated based on morphological, acoustic and molecular data. The results reveal a high level of genetic differentiation in this species. Six independent clades with nearly unique sets of haplotypes corresponding to geographically isolated populations are recognized. Genetic and geographic distances are significantly correlated among lineages. The phenotypic differentiation is generally consistent with the high levels of genetic divergence across populations. Results of ecological niche modeling suggest that the potential distribution range of this mountain-habitat specialist during the Last Glacial Maximum was broader than its current range, indicating this species had benefited from the climate change during the early Pleistocene in southern China. Geological events such as orogeny in Southwest China and Pleistocene climate oscillations have driven the differentiation and divergence of this species, and basins, plains and rivers function as natural "barriers" to block the gene flow. Besides significant genetic divergence being found among clades, the populations occurring in the Wuyi Mountains and the Hengduan Mountains are significantly different in the calling song structure from other populations. This may have resulted from significant population differentiation and subsequent adaptation of related populations. We conclude that ecological differences in habitats, coupled with geographical isolation, have driven population divergence and allopatric speciation. This study provides a plausible example of incipient speciation in Cicadidae and improves understanding of population differentiation, acoustic signal diversification and phylogeographic relationships of this unusual cicada species. It informs future studies on population differentiation, speciation and phylogeography of other mountain-habitat insects in the East Asian continent.

Novel Three-Dimensional Printed Human Heart Models and Ultrasound Omniplane Simulator for Transesophageal Echocardiography Training.

Simulation-based training plays an essential role in transesophageal echocardiography (TEE) education. Using 3-dimensional printing technology, the authors invented a novel TEE teaching system consisting of a series of heart models that can be segmented according to actual TEE views, and an ultrasound omniplane simulator to demonstrate how ultrasound beams intersect the heart at different angles and generate images. This novel teaching system is able to provide a more direct way to visualize the mechanics of obtaining TEE images than traditional online or mannequin-based simulators. It can also provide tangible feedback of both an ultrasound scan plane and a TEE view of the heart, which has been proven to improve trainees' spatial awareness and can significantly help in understanding and memorizing complex anatomic structures. This teaching system itself is also portable and inexpensive, making it conducive to teaching TEE in regions of diverse economic status. This teaching system also can be expected to be used for just-in-time training in a variety of clinical scenarios, including operating rooms, intensive care units, etc.

Novel Three-Dimensionally Printed Ultrasound Probe Simulator and Heart Model for Transthoracic Echocardiography Education.

Simulation-based training is an essential component in the education of transthoracic echocardiography (TTE). Nevertheless, current TTE teaching methods may be subject to certain limitations. Hence, the authors in this study aimed to invent a novel TTE training system employing three-dimensional (3D) printing technology to teach the basic principles and psychomotor skills of TTE imaging more intuitively and understandably. This training system comprises a 3D-printed ultrasound probe simulator and a sliceable heart model. The probe simulator incorporates a linear laser generator to enable the visualization of the projection of the ultrasound scan plane in a 3D space. By using the probe simulator in conjunction with the sliceable heart model or other commercially available anatomic models, trainees can attain a more comprehensive understanding of probe motion and related scan planes in TTE. Notably, the 3D-printed models are portable and low-cost, suggesting their potential utility in various clinical scenarios, particularly for just-in-time training.

Structural and Electrical Integrity of Transesophageal Echocardiography Probes: Importance and Key Concepts.

The clinical utility of transesophageal echocardiography (TEE) is well-established for patients undergoing cardiac surgery. With the increase in percutaneous structural heart disease procedures that rely on TEE for procedural guidance, the use of TEE probes is expanding. Although there are well-established protocols for routine cleaning and decontaminating TEE probes between patient use, there is a lack of awareness and misconceptions about maintaining TEE probes' structural and electrical integrity. The electrical leakage test (ELT) is routinely performed between patient use. From a patient safety standpoint, the ELT is necessary to ensure the longevity of this expensive equipment and prevent disruptions to the workflow in a busy department caused by TEE probes being decommissioned due to probe damage. This technical communication aims to highlight the importance of maintaining TEE probes' structural and electrical integrity. The article also highlights and discusses probe handling techniques between patient use, emphasizing the ELT to ensure patient safety and compliance with national and international standards.

Effects of atomic species and interatomic distance on the interactions in one-dimensional nanomaterials.

Noncovalent van der Waals (vdW) interactions are significant for the constitution of nanomaterials; however, they are not well understood in one-dimensional materials. Herein, we employ density functional theory (DFT) methods to address this issue and find that the many-body effects of vdW interactions within the one-dimensional wires composed of atoms chosen from the second period (B, C, N, O, F) vary with the interatomic distance of the wires. Furthermore, the atomic species effectively regulate the transition threshold of the many-body effects of vdW interactions. In the case of the adsorption of n-heptane (C7H16) on the wires, the atomic species alters the interactions between the wires and the molecule by modulating the coupling vibration between wires and C7H16 molecules. Correspondingly, replacing a portion of Pb with Tl atoms could contribute to the stability of the organic-inorganic hybrid halide perovskites with one-dimensional structures. Our findings not only contribute to the understanding of vdW interactions in one-dimensional structures with second-period atoms (B, C, N, O, F) but also provide clues for improving the stability of perovskites with one-dimensional structures.

Engineering improved thermostability of the GH11 xylanase from Neocallimastix patriciarum via computational library design.

Xylanases, which cleave the ß-1,4-glycosidic bond between xylose residues to release xylooligosaccharides (XOS), are widely used as food additives, animal feeds, and pulp bleaching agents. However, the thermally unstable nature of xylanases would hamper their industrial application. In this study, we used in silico design in a glycoside hydrolase family (GH) 11 xylanase to stabilize the enzyme. A combination of the best mutations increased the apparent melting temperature by 14 °C and significantly enhanced thermostability and thermoactivation. The variant also showed an upward-shifted optimal temperature for catalysis without compromising its activity at low temperatures. Moreover, a 10-fold higher XOS production yield was obtained at 70 °C, which compensated the low yield obtained with the wild-type enzyme. Collectively, the variant constructed by the computational strategy can be used as an efficient biocatalyst for XOS production at industrially viable conditions.

Metabolic Engineering of Escherichia coli for Producing Astaxanthin as the Predominant Carotenoid.

Astaxanthin is a carotenoid of significant commercial value due to its superior antioxidant potential and wide applications in the aquaculture, food, cosmetic and pharmaceutical industries. A higher ratio of astaxanthin to the total carotenoids is required for efficient astaxanthin production. ß-Carotene ketolase and hydroxylase play important roles in astaxanthin production. We first compared the conversion efficiency to astaxanthin in several ß-carotene ketolases from Brevundimonas sp. SD212, Sphingomonas sp. DC18, Paracoccus sp. PC1, P. sp. N81106 and Chlamydomonas reinhardtii with the recombinant Escherichia coli cells that synthesize zeaxanthin due to the presence of the Pantoea ananatis crtEBIYZ. The B. sp. SD212 crtW and P. ananatis crtZ genes are the best combination for astaxanthin production. After balancing the activities of ß-carotene ketolase and hydroxylase, an E. coli ASTA-1 that carries neither a plasmid nor an antibiotic marker was constructed to produce astaxanthin as the predominant carotenoid (96.6%) with a specific content of 7.4 ± 0.3 mg/g DCW without an addition of inducer.

Dynamic control of the mevalonate pathway expression for improved zeaxanthin production in Escherichia coli and comparative proteome analysis.

Engineered heterologous multi-gene metabolic pathways often suffer from flux imbalance and toxic metabolites, as the production host typically lacks the regulatory mechanisms for the heterologous pathway. Here, we first coordinated the expression of all genes of the mevalonate (MEV) pathway from Saccharomyces cerevisiae using the tunable intergenic regions (TIGRs), and then dynamically regulated the TIGR-mediated MEV pathway to prevent the accumulation of toxic metabolites by using IPP/FPP-responsive promoter. After introduction of the dynamically controlled TIGR-mediated MEV pathway into Escherichia coli, the content and concentration of zeaxanthin in shaker flask cultures were 2.0- and 2.1-fold higher, respectively, than those of the strain harboring the statically controlled non-TIGR-mediated MEV pathway. The content and concentration of zeaxanthin in E. coli ZEAX (pZSPgadE-MevTTIGR-MevBTIGRIS-2) reached 722.46mg/L and 23.16mg/g dry cell weight (DCW), respectively, in 5.0L fed-batch fermentation. We also comparatively analyzed the proteomes between E. coli ZEAX and E. coli ZEAX (pZSPgadE-MevTTIGR-MevBTIGRIS-2) to understand the mechanism of zeaxanthin biosynthesis. The results of the comparative proteomes demonstrate that zeaxanthin overproduction may be associated with increased precursor availability, increased NADPH availability, increased ATP availability, oxidative stress response, and increased membrane storage capacity for zeaxanthin due to changes in both cellular shape and membrane composition.

Local Geometric Effects on Stability and Energy Gap of Thiolate-Protected Gold Nanoparticles.

Thiolate-protected gold nanoclusters, Aum (SR)n , have potential applications in many fields due to their high stability and remarkable electronic properties. However, the controlling factors in determining the stability and HOMO-LUMO gap of Aum (SR)n remain controversial, despite decades of work on the topic. Through DFT calculations, including nonlocal many-body dispersion (MBD) interactions, the geometric and electronic properties of Aum (SR)n clusters are investigated. Calculations demonstrate that the MBD interactions are essential for correctly describing the geometry and energy of the clusters. Greater anisotropic polarization and more atoms distributed in the shell of the clusters lead to more pronounced MBD interactions and higher stability of the clusters. Furthermore, the HOMO-LUMO gap of the clusters strongly depends on the gold core. These results provide critical clues for understanding and designing Aum (SR)n clusters.

Fur-mediated regulation of hydrogen sulfide synthesis, stress response, and virulence in Edwardsiella piscicida.

The production of endogenous hydrogen sulfide (H2S) is an important phenotype of bacteria. H2S plays an important role in bacterial resistance to ROS and antibiotics, which significantly contributes to bacterial pathogenicity. Edwardsiella piscicida, the Gram-negative pathogen causing fish edwardsiellosis, has been documented to produce hydrogen sulfide. In the study, we revealed that Ferric uptake regulator (Fur) controlled H2S synthesis by activating the expression of phsABC operon. Besides, Fur participated in the bacterial defense against ROS and cationic antimicrobial peptides and modulated T3SS expression. Furthermore, the disruption of fur exhibited a significant in vivo colonization defect. Collectively, our study demonstrated the regulation of Fur in H2S synthesis, stress response, and virulence, providing a new perspective for better understanding the pathogenesis of Edwardsiella.

Complete genome sequence and genome-wide transposon mutagenesis enable the determination of genes required for sodium hypochlorite tolerance and drug resistance in pathogen Aeromonas veronii GD2019.

Aeromonas veronii, a significant pathogen in aquatic environments, poses a substantial threat to both human and animal health, particularly in aquaculture. In this study, we isolated A. veronii strain GD2019 from diseased largemouth bass (Micropterus salmoides) during a severe outbreak of aeromonad septicemia in Guangdong Province, China. The complete genome sequence of A. veronii GD2019 revealed that GD2019 contains a single chromosome of 4703,168 bp with an average G+C content of 58.3%. Phylogenetic analyses indicated that GD2019 forms a separate sub-branch in A. veronii and comparative genomic analyses identified the existence of an intact Type III secretion system. Moreover, to investigate the genes that are required for the conditional fitness of A. veronii under various stresses, a high-density transposon insertion library in GD2019 was generated by a Tn5-based transposon and covers 6311 genomic loci including 4155 genes and 2156 intergenic regions. Leveraging this library, 630 genes were classified as essential genes for growth in rich-nutrient LB medium. Furthermore, the genes GE001863/NtrC and GE002550 were found to confer tolerance to sodium hypochlorite in A. veronii. GE002562 and GE002614 were associated with the resistance to carbenicillin. Collectively, our results provide abundant genetic information on A. veronii, shedding light on the pathogenetic mechanisms of Aeromonas.

Constructing sequence-controlled heterolayered dendritic lanthanide chelates via a one-pot strategy using orthogonal chemistry.

The construction of sequence-controlled heterometallic lanthanide complexes is challenging despite their intriguing physical/chemical properties and enormous potential applications. Here we report a one-pot strategy that exploits orthogonal chemical reactions for modular assembly, which allows for rapid preparation of sequence-controlled heterolayered lanthanide-complex dendritic structures.