Causal role of lipid metabolism in pulmonary alveolar proteinosis: an observational and mendelian randomisation study.

BACKGROUND: Pulmonary alveolar proteinosis (PAP) is a rare interstitial lung disease characterised by the accumulation of lipoprotein material in the alveoli. Although dyslipidaemia is a prominet feature, the causal effect of lipid traits on PAP remains unclear. This study aimed to explore the role of lipid traits in PAP and evaluate the potential of lipid-lowering drug targets in PAP. METHODS: Clinical outcomes, lipid profiles and lung function tests were analysed in a clinical cohort of diagnosed PAP patients and propensity score-matched healthy controls. Genome-wide association study data on PAP, lipid metabolism, blood cells and variants of genes encoding potential lipid-lowering drug targets were obtained for Mendelian randomisation (MR) and mediation analyses. FINDINGS: Observational results showed that higher levels of total cholesterol (TC), triglycerides and low-density lipoprotein (LDL) were associated with increased risks of PAP. Higher levels of TC and LDL were also associated with worse PAP severity. In MR analysis, elevated LDL was associated with an increased risk of PAP (OR: 4.32, 95% CI: 1.63 to 11.61, p=0.018). Elevated monocytes were associated with a lower risk of PAP (OR 0.34, 95% CI: 0.18 to 0.66, p=0.002) and mediated the risk impact of LDL on PAP. Genetic mimicry of PCSK9 inhibition was associated with a reduced risk of PAP (OR 0.03, p=0.007). INTERPRETATION: Our results support the crucial role of lipid and metabolism-related traits in PAP risk, emphasising the monocyte-mediated, causal effect of elevated LDL in PAP genetics. PCSK9 mediates the development of PAP by raising LDL. These finding provide evidence for lipid-related mechanisms and promising lipid-lowering drug target for PAP.

Impact of diabetes on COVID-19 and glucocorticoids on patients with COVID-19 and diabetes during the Omicron variant epidemic: a multicenter retrospective cohort study in South China.

BACKGROUND: To explore the impact of diabetes on the clinical features and prognosis of COVID-19 and assess the influence of glucocorticoid use on the prognosis of patients with COVID-19 and diabetes. METHODS: This retrospective multicenter cohort study included patients admitted between December 2022 and January 2023. The patients were grouped according to diabetes and glucocorticoid use. The primary outcome was in-hospital mortality. RESULTS: Among 400 patients with glucocorticoid data, 109 (27.3%) had diabetes. The inflammatory cytokines were higher in patients with diabetes, manifested by higher IL-6 (25.33 vs. 11.29 ng/L, p = 0.011), CRP (26.55 vs. 8.62 mg/L, p = 0.003), and PCT (0.07 vs. 0.04 ng/ml, p = 0.010), while CD4+ (319 vs. 506 /mL, p = 0.004) and CD8+ (141 vs. 261 /mL, p < 0.001) T lymphocytes were lower. The overall mortality rate of hospitalized COVID-19 patients with diabetes was 13.46%. The diabetic patients who received glucocorticoids vs. those who did not receive glucocorticoids had a similar mortality (15.00% vs. 11.39%, p = 0.591). CONCLUSIONS: Patients with COVID-19 and diabetes are more likely to experience hyperinflammatory response and T cell reduction, especially those with severe/critical disease. Glucocorticoid use was not associated with the prognosis of COVID-19 in patients with diabetes. Still, glucocorticoids should be used cautiously in diabetic patients with severe/critical COVID-19.

The Waxy Gene Has Pleiotropic Effects on Hot Water-Soluble and -Insoluble Amylose Contents in Rice (Oryza sativa) Grains.

Rice (Oryza sativa) is a cereal crop with a starchy endosperm. Starch is composed of amylose and amylopectin. Amylose content (AC) is the principal determinant of rice quality, but varieties with similar ACs can still vary substantially in their quality. In this study, we analyzed the total AC (TAC) and its constituent fractions, the hot water-soluble amylose content (SAC) and hot water-insoluble amylose content (IAC), in two sets of related chromosome segment substitution lines of rice with a common genetic background grown in two years. We searched for quantitative trait loci (QTLs) associated with SAC, IAC, and TAC and identified one common QTL (qSAC-6, qIAC-6, and qTAC-6) on chromosome 6. Map-based cloning revealed that the gene underlying the trait associated with this common QTL is Waxy (Wx). An analysis of the colors of soluble and insoluble starch-iodine complexes and their λmax values (wavelengths at the positions of their peak absorbance values) as well as gel permeation chromatography revealed that Wx is responsible for the biosynthesis of amylose, comprising a large proportion of the soluble fractions of the SAC. Wx is also involved in the biosynthesis of long chains of amylopectin, comprising the hot water-insoluble fractions of the IAC. These findings highlight the pleiotropic effects of Wx on the SAC and IAC. This pleiotropy indicates that these traits have a positive genetic correlation. Therefore, further studies of rice quality should use rice varieties with the same Wx genotype to eliminate the pleiotropic effects of this gene, allowing the independent relationship between the SAC or IAC and rice quality to be elucidated through a multiple correlation analysis. These findings are applicable to other valuable cereal crops as well.

A Directly Moldable, Highly Compact, and Easy-for-Integration 3D Micromixer with Extraordinary Mixing Performance.

Micromixers are a critical component in microfluidics. However, most 2D passive micromixers produce optimal mixing at a high flow rate range and 3D micromixers require mm-scale channels or a complex assembly that is unsuitable for microfluidic applications. Here, we reported a 3D PDMS micromixer based on the splitting-stretching-recombination (SSR) of streams to facilitate molecular diffusion, which can effectively and rapidly mix solutions with low Reynolds numbers (0.01-10). The fabrication of our micromixer is convenient with only two steps─two-photon polymerization (2PP) 3D printing and soft lithography, with high resolution, reproducibility, and ease for integration. We investigated the mixing performance of the micromixer by CFD simulations and experimental studies under a confocal microscope; the results confirmed its better performance and higher chip miniaturization than others. It can achieve a mixing efficiency above 0.90 (which is generally regarded as complete mixing) for low-Re solutions (flow rates ≤60 µL/min) with a mixing volume smaller than 20 nL. The time for complete mixing is in the range of milliseconds (e.g., 21 ms for Re = 10, 194 ms for Re = 0.88). The device shows negligible degradation in mixing performance for highly viscous solutions (∼50 times more viscous than water), macromolecule solutions, and colloidal solutions of nanoparticles.

Mechanical stretch promotes apoptosis and impedes ciliogenesis of primary human airway basal stem cells.

BACKGROUND: Airway basal stem cells (ABSCs) have self-renewal and differentiation abilities. Although an abnormal mechanical environment related to chronic airway disease (CAD) can cause ABSC dysfunction, it remains unclear how mechanical stretch regulates the behavior and structure of ABSCs. Here, we explored the effect of mechanical stretch on primary human ABSCs. METHODS: Primary human ABSCs were isolated from healthy volunteers. A Flexcell FX-5000 Tension system was used to mimic the pathological airway mechanical stretch conditions of patients with CAD. ABSCs were stretched for 12, 24, or 48 h with 20% elongation. We first performed bulk RNA sequencing to identify the most predominantly changed genes and pathways. Next, apoptosis of stretched ABSCs was detected with Annexin V-FITC/PI staining and a caspase 3 activity assay. Proliferation of stretched ABSCs was assessed by measuring MKI67 mRNA expression and cell cycle dynamics. Immunofluorescence and hematoxylin-eosin staining were used to demonstrate the differentiation state of ABSCs at the air-liquid interface. RESULTS: Compared with unstretched control cells, apoptosis and caspase 3 activation of ABSCs stretched for 48 h were significantly increased (p < 0.0001; p < 0.0001, respectively), and MKI67 mRNA levels were decreased (p < 0.0001). In addition, a significant increase in the G0/G1 population (20.2%, p < 0.001) and a significant decrease in S-phase cells (21.1%, p < 0.0001) were observed. The ratio of Krt5+ ABSCs was significantly higher (32.38% vs. 48.71%, p = 0.0037) following stretching, while the ratio of Ac-tub+ cells was significantly lower (37.64% vs. 21.29%, p < 0.001). Moreover, compared with the control, the expression of NKX2-1 was upregulated significantly after stretching (14.06% vs. 39.51%, p < 0.0001). RNA sequencing showed 285 differentially expressed genes, among which 140 were upregulated and 145 were downregulated, revealing that DDIAS, BIRC5, TGFBI, and NKX2-1 may be involved in the function of primary human ABSCs during mechanical stretch. There was no apparent difference between stretching ABSCs for 24 and 48 h compared with the control. CONCLUSIONS: Pathological stretching induces apoptosis of ABSCs, inhibits their proliferation, and disrupts cilia cell differentiation. These features may be related to abnormal regeneration and repair observed after airway epithelium injury in patients with CAD.

Deep Learning-Based Segmentation of Airway Morphology from Endobronchial Optical Coherence Tomography.

BACKGROUND: Manual measurement of endobronchial optical coherence tomography (EB-OCT) images means a heavy workload in the clinical practice, which can also introduce bias if the subjective opinions of doctors are involved. OBJECTIVE: We aim to develop a convolutional neural network (CNN)-based EB-OCT image analysis algorithm to automatically identify and measure EB-OCT parameters of airway morphology. METHODS: The ResUNet, MultiResUNet, and Siamese network were used for analyzing airway inner area (Ai), airway wall area (Aw), airway wall area percentage (Aw%), and airway bifurcate segmentation obtained from EB-OCT imaging, respectively. The accuracy of the automatic segmentations was verified by comparing with manual measurements. RESULTS: Thirty-three patients who were diagnosed with asthma (n = 13), chronic obstructive pulmonary disease (COPD, n = 13), and normal airway (n = 7) were enrolled. EB-OCT was performed in RB9 segment (lateral basal segment of the right lower lobe), and a total of 17,820 OCT images were collected for CNN training, validation, and testing. After training, the Ai, Aw, and airway bifurcate were readily identified in both normal airway and airways of asthma and COPD. The ResUNet and the MultiResUNet resulted in a mean dice similarity coefficient of 0.97 and 0.95 for Ai and Aw segmentation. The accuracy Siamese network in identifying airway bifurcate was 96.6%. Bland-Altman analysis indicated there was a negligible bias between manual and CNN measurements for Ai (bias = -0.02 to 0.01, 95% CI = -0.12 to 0.14) and Aw% (bias = -0.06 to 0.12, 95% CI = -1.98 to 2.14). CONCLUSION: EB-OCT imaging in conjunction with ResUNet, MultiResUNet, and Siamese network could automatically measure normal and diseased airway structure with an accurate performance.

Similarity measurements of B cell receptor repertoire in baseline mice showed spectrum convergence of IgM.

BACKGROUND: The B cell receptor (BCR) repertoire is highly diverse among individuals. Poor similarity of the spectrum among inbred baseline mice may limit the ability to discriminate true signals from those involving specific experimental factors. The repertoire similarity of the baseline status lacks intensive measurements. RESULTS: We measured the repertoire similarity of IgH in blood and spleen samples from untreated BALB/c and C57BL/6J mice to investigate the baseline status of the two inbred strains. The antibody pool was stratified by the isotype of IgA, IgG and IgM. Between individuals, the results showed better convergence of CDR3 and clonal lineage profiles in IgM than in IgA and IgG, and better robustness of somatic mutation networks in IgM than in IgA and IgG. It also showed that the CDR3 clonotypes and clonal lineages shared better in the spleen samples than in the blood samples. The animal batch differences were detected in CDR3 evenness, mutated clonotype proportions, and maximal network degrees. A cut-off of 95% identity in the CDR3 nucleotide sequences was suitable for clonal lineage establishment. CONCLUSIONS: Our findings reveal a natural landscape of BCR repertoire similarities between baseline mice and provide a solid reference for designing studies of mouse BCR repertoires.

Crack engineering for the construction of arbitrary hierarchical architectures.

Three-dimensional hierarchical morphologies widely exist in natural and biomimetic materials, which impart preferential functions including liquid and mass transport, energy conversion, and signal transmission for various applications. While notable progress has been made in the design and manufacturing of various hierarchical materials, the state-of-the-art approaches suffer from limited materials selection, high costs, as well as low processing throughput. Herein, by harnessing the configurable elastic crack engineering-controlled formation and configuration of cracks in elastic materials-an effect normally avoided in various industrial processes, we report the development of a facile and powerful technique that enables the faithful transfer of arbitrary hierarchical structures with broad material compatibility and structural and functional integrity. Our work paves the way for the cost-effective, large-scale production of a variety of flexible, inexpensive, and transparent 3D hierarchical and biomimetic materials.

The divergence of brassinosteroid sensitivity between rice subspecies involves natural variation conferring altered internal auto-binding of OsBSK2.

Japonica/geng and indica/xian are two major rice (Oryza sativa) subspecies with multiple divergent traits, but how these traits are related and interact within each subspecies remains elusive. Brassinosteroids (BRs) are a class of steroid phytohormones that modulate many important agronomic traits in rice. Here, using different physiological assays, we revealed that japonica rice exhibits an overall lower BR sensitivity than indica. Extensive screening of BR signaling genes led to the identification of a set of genes distributed throughout the primary BR signaling pathway with divergent polymorphisms. Among these, we demonstrate that the C38/T variant in BR Signaling Kinase2 (OsBSK2), causing the amino acid change P13L, plays a central role in mediating differential BR signaling in japonica and indica rice. OsBSK2L13 in indica plays a greater role in BR signaling than OsBSK2P13 in japonica by affecting the auto-binding and protein accumulation of OsBSK2. Finally, we determined that OsBSK2 is involved in a number of divergent traits in japonica relative to indica rice, including grain shape, tiller number, cold adaptation, and nitrogen-use efficiency. Our study suggests that the natural variation in OsBSK2 plays a key role in the divergence of BR signaling, which underlies multiple divergent traits between japonica and indica.

Tuning an Electrode Work Function Using Organometallic Complexes in Inverted Perovskite Solar Cells.

Low-work-function (WF) metals (including silver (Ag), aluminum (Al), and copper (Cu)) used as external cathodes in inverted perovskite solar cells (PSCs) encounter oxidation caused by air exposure and halogen-diffusion-induced corrosion, which threaten the long-term stability of the device. The cathode interlayer (CIL) has shown promise in reducing the metal WF and thus boosting the device power conversion efficiency (PCE). However, it remains a challenge for current CIL materials to enable high-WF metals (e.g., Au) to be used as cathodes to achieve PSCs with a superior PCE and long-term stability. Here, we use a series of synthesized (carbolong-derived) organometallic complexes as CILs to tune the electrode WF in inverted PSCs. Density functional theory calculations and surface characterizations show that the organometallic complexes that contain anions and cations are prone to form anion-cation dipoles on the metal surface, hence drastically reducing the metal's WF. Photovoltaic devices based on a Ag cathode, which was modified with these organometallic complexes, received a boosted PCE up to 21.29% and a remarkable fill factor that reached 83.52%, which are attributed to the dipole-enhanced carrier transport. The environmental stability of PSCs was further improved after employing Au as a cathode with these organometallic complexes, and the modified devices exhibited no efficiency loss after 4080 h storage measurements.

Optimization of Factor Combinations for Stem Cell Differentiations on a Design-of-Experiment Microfluidic Chip.

Directed differentiation of stem cells plays a vital role in cell replacement therapy. Many activators and inhibitors targeting different signaling pathways have been identified to contribute to each step of differentiation. Most studies relied on empirically optimizing the combinations of the aforementioned factors for each step to optimize the efficiency of differentiation, which are time-consuming and nonsystematic. Design-of-experiment (DOE) is a powerful strategy to identify the critical combinations from multiple factors systematically. However, it is prohibitively complicated for typical laboratories, given a large number of potential combinations. Here, we develop a multilayer polymethyl methacrylate-based, reusable microfluidic chip to directly facilitate the DOE in the differentiation of stem cells. The chip consists of an inlet layer and multiple disperse layers. Different solutions are injected simultaneously to the chip through the inlet layer. Subsequently, the channels in the disperse layers split and recombine the flow streams to generate solution combinations based on hard-wired DOE designs. We demonstrated that it is in quantitative agreement with the designs using fluorescent dyes. Moreover, we constructed a human-induced pluripotent stem reporter cell line to improve the consistency of the cellular state measurements and use the chip to identify critical factors for cell differentiation to definitive endoderm (DE). We found that the differentiation efficiencies under various factor combinations are significantly different, and CHIR99201 and GDF8 are the most critical factors for differentiation to DE. Our method is potentially applicable to the optimization of factor combinations for multi-step stem cell differentiation and combinatorial drug screening.

Distinct T-cell receptor profiles associated with hepatitis B e antigen seroconversion during entecavir treatment.

BACKGROUND & AIMS: T-cell receptor (TCR) repertoire is ambiguously changed in chronic hepatitis B (CHB) patients during antivirus therapy. We tried to assess TCR repertoire dynamics and its clinical significance upon HBeAg seroconversion in CHB patients. METHODS: Twenty CHB patients undergoing 1-year entecavir (ETV) treatment were enrolled, including 10 complete response (CR) vs 10 non-complete response (NCR) patients based on HBeAg seroconversion at week 48. The TCRß complementarity-determining region 3 (CDR3) of peripheral CD4+ and CD8+ T cells at weeks 0, 12 and 48 was analyzed by unbiased high-throughput sequencing. The TCR repertoire profiles and their correlations with serological parameters were analyzed. RESULTS: The diversity of TCRß repertoires was decreasing in CR patients but increasing in NCR patients. The distribution pattern of TCR repertoires stratified according to clonotype frequencies changed in the opposite direction between CR and NCR patients. Narrow amounts of newly appearing clonotypes in CR patients experienced a more intensive and robust expansion and this phenomenon could occur as early as week 12 for the CD4+ subset but later at week 48 for the CD8+ subset. There existed some CR-exclusive clonotypes with a relatively low but increasing frequency at week 48. The number of unique TCRß clonotypes was positively correlated with the ALT or HBV DNA level in CR patients but showed no or negative correlation in NCR patients. CONCLUSION: Distinct TCR profiles contribute to predicting HBeAg seroconversion in CHB patients during ETV treatment and certain TCRß CDR3 motif may be utilized for CHB immunotherapy in the future.

The incidence, risk factors and prognosis of acute kidney injury in severe and critically ill patients with COVID-19 in mainland China: a retrospective study.

BACKGROUND: The clinical correlates, prognosis and determinants of acute kidney injury (AKI) in patients with coronavirus disease 2019 (Covid-19) remain largely unclear. METHODS: We retrospectively reviewed medical records of all adult patients with laboratory-confirmed Covid-19 who were admitted to the intensive care unit (ICU) between January 23rd 2020 and April 6th 2020 at Wuhan JinYinTan Hospital and The First Affiliated Hospital of Guangzhou Medical University. RESULTS: Among 210 patients, 131 were males (62.4%). The median Age was 64 years (IQR: 56-71). Of 92 (43.8%) patients who developed AKI during hospitalization, 13 (14.1%), 15 (16.3%) and 64 (69.6%) were classified as being at stage 1, 2 and 3, respectively. 54 patients (58.7%) received continuous renal replacement therapy. Age, sepsis, nephrotoxic drug, invasive mechanical ventilation and elevated baseline serum creatinine levels were associated with the occurrence of AKI. Renal recovery during hospitalization was identified among 16 patients with AKI (17.4%), who had a significantly shorter time from admission to AKI diagnosis, lower incidence of right heart failure and higher ratio of partial pressure of oxygen to the fraction of inspired oxygen. Of 210 patients, 93 deceased within 28 days of ICU admission. AKI stage 3, critical disease, greater Age and the lowest ratio of partial pressure of oxygen to the fraction of inspired oxygen being < 150 mmHg were independently associated with death. CONCLUSIONS: Among patients with Covid-19, the incidence of AKI was high. Our findings of the risk factors of the development of AKI and factors associated with renal function recovery may inform clinical management of patients with critical illness of Covid-19.

A Controllable, Centrifugal-Based Hydrodynamic Microfluidic Chip for Cell-Pairing and Studying Long-Term Communications between Single Cells.

Investigation of cell-cell interactions between individual cells in a well-defined microenvironment is critical for the understanding of specific intercellular communications and interactions. However, most current studies in multicellular systems are often overwhelmed by additional complicated interactions. Cell-pairing based on a microfluidic chip provides a potential strategy to simplify the studies. Here, we report a robust and straightforward method, relying on a combination of hydrodynamic single-cell capture and centrifugation-assisted relocation of individual cells, which can be applied, in general, to various cell types for cell-pairing and studying cell interactions at the single-cell level. This microfluidic chip is simple to operate and easily controlled, which requires only two operational steps-capturing individual cells with hydrodynamic traps and subsequently relocating the capture cells by centrifugation. With this microfluidic chip, we demonstrated homotypic cell-pairing, heterotypic cell-pairing, and long-term cell coculture, which exhibited better or comparable performance compared with previous cell-pairing methods. Its single-cell trapping and cell-pairing efficiencies are ∼74% and ∼20%, respectively. As a proof of concept, we paired individual dHL-60 cells and HeLa cells (HeLa-IL8, HeLa-IL10, and wild-type HeLa cells) in multiple cell chambers. The HeLa-IL8 and HeLa-IL10, both engineered with a light-induced gene expression system, can secret interleukin-8 and interleukin-10, respectively, under blue light illumination. We found that these three HeLa cell lines have very different influences on the migration of dHL-60 cells. This platform demonstrates its potential applications in studies of intercellular communication (paracrine), and it can be extended to trap three or more individual cells for more complex biological systems.

Microfluidic technologies for vasculature biomimicry.

Microfluidic technology has been extensively employed in biology and medicine since the field emerged in the 1990s. By utilizing microfluidic approaches, a variety of vascular system-related structures and functions have been mimicked on in vitro platforms. Herein, we begin by introducing microfluidic circulatory devices for the study of two-dimensional (2D) endothelial cells culture. Next, we focus on recent progress on on-chip mimicry of native vasculature, specifically generation of complex three-dimensional (3D) structures within cell-laden hydrogels using microfluidics and self-assembly-based methods. The utilization of microfluidic technology will facilitate the construction of progressively biomimetic in vitro models that have great potential in complementing existing animal models. We envision such platforms to be utilized in a wide range of applications involving vascular systems, including microphysiological studies, drug screening, and disease modeling.

Molecular evolution of human adenovirus type 16 through multiple recombination events.

Human mastadenoviruses (HAdVs) are non-enveloped, double-stranded DNA viruses that are comprised of more than 85 types classified within seven species (A-G) based on genomics. All HAdV prototypes and many newly defined type genomes have been completely sequenced and are available. Computational analyses of the prototypes and newly emergent HAdV strains provide insights into the evolutionary history and molecular adaptation of HAdV. Most types of HAdV-B are important pathogens causing severe respiratory infections or urinary tract infections and are well characterized. However, HAdV-16 of the B1 subspecies has rarely been reported and its genome is poorly characterized. In this study, bioinformatics analysis, based on genome sequences obtained in GenBank, suggested that HAdV-16, a prototype HAdV-B species, evolved from multiple intertypic recombination events. HAdV-16 genome contains the hexon loop 1 to loop 2 region from HAdV-E4, the partial hexon conserved region 4 (C4) from the subspecies HAdV-B2, genome region 30,897-33,384 containing the fiber gene from SAdV-35, and other genomic parts from the subspecies HAdV-B1. Moreover, analysis of sequence similarity with HAdV-E4 LI, LII, and SAdV-36 strains demonstrated the recombination events happened rather early. Further, amino acid sequence alignment indicated that the amino acid variations occurred in hypervariable regions (HVRs). Especially, the major difference in HVR7, which contains the critical neutralization epitope of HAdV-E4, between HAdV-16 and HAdV-E4 might explain the low level of cross-neutralization between these strains. Our findings promote better understanding on HAdV evolution, predicting newly emergent HAdV strains, and developing novel HAdV vectors.

Emergence and genomic analysis of MDR Laribacter hongkongensis strain HLGZ1 from Guangzhou, China.

Background: Laribacter hongkongensis is a facultative anaerobic, non-fermentative, Gram-negative bacillus associated with community-acquired gastroenteritis and traveller's diarrhoea. No clinical MDR L. hongkongensis isolate has been reported yet. Methods: We performed WGS (PacBio and Illumina) on a clinical L. hongkongensis strain HLGZ1 with an MDR phenotype. Results: HLGZ1 was resistant to eight classes of commonly used antibiotics. Its complete genome was a single circular chromosome of 3 424 272 bp with a G + C content of 62.29%. In comparison with the reference strain HLHK9, HLGZ1 had a higher abundance of genes associated with DNA metabolism and recombination. Several inserts including two acquired resistance gene clusters (RC1 and RC2) were also identified. RC1 carried two resistance gene cassette arrays, aac(6')-Ib-cr-aadA2-Δqac-Δsul1-floR-tetR-tetG and arr-3-dfrA32-ereA2-Δqac-sul1, which shared significant nucleotide sequence identities with the MDR region of Salmonella Genomic Island 1 from Salmonella enterica serovar Typhimurium DT104. There was also an integron-like structure, intl1-arr3-dfrA27-Δqac-sul1-aph(3')-Ic, and a tetR-tetA operon located on RC2. MLST analysis identified HLGZ1 as ST167, a novel ST clustered with two strains previously isolated from frogs. Conclusions: This study provides insight into the genomic characteristics of MDR L. hongkongensis and highlights the possibilities of horizontal resistance gene transfer in this bacterium with other pathogens.

A Rapidly Self-Healing Host-Guest Supramolecular Hydrogel with High Mechanical Strength and Excellent Biocompatibility.

It is still a challenge to achieve both excellent mechanical strength and biocompatibility in hydrogels. In this study, we exploited two interactions to form a novel biocompatible, slicing-resistant, and self-healing hydrogel. The first was molecular host-guest recognition between a host (isocyanatoethyl acrylate modified ß-cyclodextrin) and a guest (2-(2-(2-(2-(adamantyl-1-oxy)ethoxy)ethoxy)ethoxy)ethanol acrylate) to form "three-arm" host-guest supramolecules (HGSMs), and the second was covalent bonding between HGSMs (achieved by UV-initiated polymerization) to form strong cross-links in the hydrogel. The host-guest interaction enabled the hydrogel to rapidly self-heal. When it was cut, fresh surfaces were formed with dangling host and guest molecules (due to the breaking of host-guest recognition), which rapidly recognized each other again to heal the hydrogel by recombination of the cut surfaces. The smart hydrogels hold promise for use as biomaterials for soft-tissue repair.

OsNAP connects abscisic acid and leaf senescence by fine-tuning abscisic acid biosynthesis and directly targeting senescence-associated genes in rice.

It has long been established that premature leaf senescence negatively impacts the yield stability of rice, but the underlying molecular mechanism driving this relationship remains largely unknown. Here, we identified a dominant premature leaf senescence mutant, prematurely senile 1 (ps1-D). PS1 encodes a plant-specific NAC (no apical meristem, Arabidopsis ATAF1/2, and cup-shaped cotyledon2) transcriptional activator, Oryza sativa NAC-like, activated by apetala3/pistillata (OsNAP). Overexpression of OsNAP significantly promoted senescence, whereas knockdown of OsNAP produced a marked delay of senescence, confirming the role of this gene in the development of rice senescence. OsNAP expression was tightly linked with the onset of leaf senescence in an age-dependent manner. Similarly, ChIP-PCR and yeast one-hybrid assays demonstrated that OsNAP positively regulates leaf senescence by directly targeting genes related to chlorophyll degradation and nutrient transport and other genes associated with senescence, suggesting that OsNAP is an ideal marker of senescence onset in rice. Further analysis determined that OsNAP is induced specifically by abscisic acid (ABA), whereas its expression is repressed in both aba1 and aba2, two ABA biosynthetic mutants. Moreover, ABA content is reduced significantly in ps1-D mutants, indicating a feedback repression of OsNAP on ABA biosynthesis. Our data suggest that OsNAP serves as an important link between ABA and leaf senescence. Additionally, reduced OsNAP expression leads to delayed leaf senescence and an extended grain-filling period, resulting in a 6.3% and 10.3% increase in the grain yield of two independent representative RNAi lines, respectively. Thus, fine-tuning OsNAP expression should be a useful strategy for improving rice yield in the future.

Fast Single-Cell Patterning for Study of Drug-Induced Phenotypic Alterations of HeLa Cells Using Time-of-Flight Secondary Ion Mass Spectrometry.

A facile single-cell patterning (ScP) method was developed and integrated with time-of-flight secondary ion mass spectrometry (TOF-SIMS) for the study of drug-induced cellular phenotypic alterations. Micropatterned poly(dimethylsiloxane) (PDMS) stencil film and centrifugation-assisted cell trapping were combined for the preparation of on-surface single-cell microarrays, which exhibited both high site occupancy (>90%) and single-cell resolution (>97%). TOF-SIMS is a surface-sensitive mass spectrometry and is increasingly utilized in biological studies. Here we demonstrated, for the first time, its successful application in high-throughput single-cell analysis. Drug-induced phenotypic alterations of HeLa cells in the early stage of apoptosis were investigated using TOF-SIMS. The major molecular sources of variations were analyzed by principle component analysis (PCA).