Alkynyl Acylazolium: a Versatile 1,3-Bielectrophilic 3C-Synthon in NHC-Organocatalysis.

N-Heterocyclic carbene (NHC) organocatalysis has emerged as a powerful tool in the field of modern organic synthesis especially in the asymmetric construction of various cyclic skeletons. As an emerging NHC-bound 1,3-bielectrophilic intermediate, alkynyl acylazolium has drawn substantial attention in recent years, and has been used as a versatile 3C-synthon in synthesizing valuable organic molecules since its discovery. In this review, focused on the different pathways for the formation of alkynyl acylazoliums from different precursors like alkynoic esters, alkynoic acids and ynals, the recent advances in the transformations and applications of alkynyl acylazoliums pioneered or developed over the last decade under NHC-catalysis were summarized comprehensively. At the same time, the outlook for further investigation and exploration of novel reaction modes for alkynyl acylazoliums in the future was also discussed.

Engineered bacteria producing aryl-hydrocarbon receptor agonists protect against ethanol-induced liver disease in mice.

BACKGROUND AND PURPOSE: Gut bacteria metabolize tryptophan into indoles. Intestinal levels of the tryptophan metabolite indole-3-acetic acid are reduced in patients with alcohol-associated hepatitis. Supplementation of indole-3-acetic acid protects against ethanol-induced liver disease in mice. The aim of this study was to evaluate the effect of engineered bacteria producing indoles as Aryl-hydrocarbon receptor (Ahr) agonists. METHODS: C57BL/6 mice were subjected to chronic-plus-binge ethanol feeding and orally given PBS, control Escherichia coli Nissle 1917 (EcN) or engineered EcN-Ahr. The effects of EcN and EcN-Ahr were also examined in mice lacking Ahr in interleukin 22 (Il22)-producing cells. RESULTS: Through the deletion of endogenous genes trpR and tnaA, coupled with overexpression of a feedback-resistant tryptophan biosynthesis operon, EcN-Ahr were engineered to overproduce tryptophan. Additional engineering allowed conversion of this tryptophan to indoles including indole-3-acetic acid and indole-3-lactic acid. EcN-Ahr ameliorated ethanol-induced liver disease in C57BL/6 mice. EcN-Ahr upregulated intestinal gene expression of Cyp1a1, Nrf2, Il22, Reg3b, and Reg3g, and increased Il22-expressing type 3 innate lymphoid cells. In addition, EcN-Ahr reduced translocation of bacteria to the liver. The beneficial effect of EcN-Ahr was abrogated in mice lacking Ahr expression in Il22-producing immune cells. CONCLUSIONS: Our findings indicate that tryptophan metabolites locally produced by engineered gut bacteria mitigate liver disease via Ahr-mediated activation in intestinal immune cells.

Nutrient availability of roughages in isocaloric and isonitrogenous diets alters the bacterial networks in the whole gastrointestinal tract of Hu sheep.

BACKGROUND: The nutrient availability of roughages could affect the dietary utilization efficiency of ruminants even in isocaloric and isonitrogenous diets. Here, we analyzed the bacterial composition and their metabolic pathways in the gastrointestinal tracts (GITs) of Hu sheep fed with wheat straw (WS) instead of alfalfa (AL) in isocaloric and isonitrogenous diets, trying to explore the reasons from the perspective of GITs bacterial network structure changes. RESULTS: We employed 16S rRNA gene sequencing in combination with the Kruskal-Wallis test, Spearman correlation analysis, and other statistical methods to describe the microbiota composition in the GITs of Hu sheep. The results showed after the roughage was replaced from AL to WS, the most positive response occurred in the rumen microbiota, resulting in a more obvious microbiological and functional redundancy phenomenon. Whereas extended biogeographic studies of the GITs bacterial community found opposite results for the hindgut microbiota and metabolism networks compared to the forestomach. The abundance of fiber-degrading bacteria such as Prevotella, Oscillospiraceae NK4A214 group, and Treponema was significantly increased in GITs, but low-efficiency crude fiber degradation inhibited energy use efficiency, the pentose phosphate pathway, gluconeogenesis, and volatile acid synthesis. In addition, dietary shifting from AL to WS decreased the abundance of beneficial bacteria such as the Lachnospiraceae NK3A20 group and Alistipes, thereby enhancing the underlying inflammatory response. CONCLUSIONS: These findings suggest that feeding untreated WS affected the structure and function of the bacterial network in the GITs due to limited total digestible nutrients, and in particular increases the complexity of the rumen bacterial network, and limit the abundance of bacteria involved in the crude fiber degradation in the hindgut.

Inferring synchronizability of networked heterogeneous oscillators with machine learning.

In the study of network synchronization, an outstanding question of both theoretical and practical significance is how to allocate a given set of heterogeneous oscillators on a complex network in order to improve the synchronization performance. Whereas methods have been proposed to address this question in the literature, the methods are all based on accurate models describing the system dynamics, which, however, are normally unavailable in realistic situations. Here, we show that this question can be addressed by the model-free technique of a feed-forward neural network (FNN) in machine learning. Specifically, we measure the synchronization performance of a number of allocation schemes and use the measured data to train a machine. It is found that the trained machine is able to not only infer the synchronization performance of any new allocation scheme, but also find from a huge amount of candidates the optimal allocation scheme for synchronization.

Artificial-intelligence-based computed tomography histogram analysis predicting tumor invasiveness of lung adenocarcinomas manifesting as radiological part-solid nodules.

Background: Tumor invasiveness plays a key role in determining surgical strategy and patient prognosis in clinical practice. The study aimed to explore artificial-intelligence-based computed tomography (CT) histogram indicators significantly related to the invasion status of lung adenocarcinoma appearing as part-solid nodules (PSNs), and to construct radiomics models for prediction of tumor invasiveness. Methods: We identified surgically resected lung adenocarcinomas manifesting as PSNs in Peking University People's Hospital from January 2014 to October 2019. Tumors were categorized as adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), and invasive adenocarcinoma (IAC) by comprehensive pathological assessment. The whole cohort was randomly assigned into a training (70%, n=832) and a validation cohort (30%, n=356) to establish and validate the prediction model. An artificial-intelligence-based algorithm (InferRead CT Lung) was applied to extract CT histogram parameters for each pulmonary nodule. For feature selection, multivariate regression models were built to identify factors associated with tumor invasiveness. Logistic regression classifier was used for radiomics model building. The predictive performance of the model was then evaluated by ROC and calibration curves. Results: In total, 299 AIS/MIAs and 889 IACs were included. In the training cohort, multivariate logistic regression analysis demonstrated that age [odds ratio (OR), 1.020; 95% CI, 1.004-1.037; p=0.017], smoking history (OR, 1.846; 95% CI, 1.058-3.221; p=0.031), solid mean density (OR, 1.014; 95% CI, 1.004-1.024; p=0.008], solid volume (OR, 5.858; 95% CI, 1.259-27.247; p = 0.037), pleural retraction sign (OR, 3.179; 95% CI, 1.057-9.559; p = 0.039), variance (OR, 0.570; 95% CI, 0.399-0.813; p=0.002), and entropy (OR, 4.606; 95% CI, 2.750-7.717; p<0.001) were independent predictors for IAC. The areas under the curve (AUCs) in the training and validation cohorts indicated a better discriminative ability of the histogram model (AUC=0.892) compared with the clinical model (AUC=0.852) and integrated model (AUC=0.886). Conclusion: We developed an AI-based histogram model, which could reliably predict tumor invasiveness in lung adenocarcinoma manifesting as PSNs. This finding would provide promising value in guiding the precision management of PSNs in the daily practice.

[Prediction of Lymph Node Metastasis of Mixed Ground-glass Nodules 
Based on Clinical Imaging Information].

BACKGROUND: Previous studies have shown that lymph node metastasis only occurs in some mixed ground-glass nodules (mGGNs) which the pathological results were invasive adenocarcinoma (IAC). However, the presence of lymph node metastasis leads to the upgrading of tumor-node-metastasis (TNM) stage and worse prognosis of the patients, so it is important to perform the necessary evaluation before surgery to guide the operation method of lymph node. The aim of this study was to find suitable clinical and radiological indicators to distinguish whether mGGNs with pathology as IAC is accompanied by lymph node metastasis, and to construct a prediction model for lymph node metastasis. METHODS: From January 2014 to October 2019, the patients with resected IAC appearing as mGGNs in computed tomography (CT) scan were reviewed. All the lesions were divided into two groups (with lymph node metastasis or not) according to their lymph node status. Lasso regression model analysis by applying R software was used to evaluate the relationship between clinical and radiological parameters and lymph node metastasis of mGGNs. RESULTS: A total of 883 mGGNs patients were enroled in this study, among which, 12 (1.36%) showed lymph node metastasis. Lasso regression model analysis of clinical imaging information in mGGNs with lymph node metastasis showed that previous history of malignancy, mean density, mean density of solid components, burr sign and percentage of solid components were informative. Prediction model for lymph node metastasis in mGGNs was developed based on the results of Lasso regression model with area under curve=0.899. CONCLUSIONS: Clinical information combined with CT imaging information can predict lymph node metastasis in mGGNs.

Complete biodegradation of the oldest organic herbicide 2,4-Dichlorophenoxyacetic acid by engineering Escherichia coli.

After nearly 80 years of extensive application, the oldest organic herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) has caused many problems of environmental pollution and ecological deterioration. Bioremediation is an ideal method for pollutant treatment. However, difficult screening and preparation of efficient degradation bacteria have largely hindered its application in 2,4-D remediation. We have created a novel engineering Escherichia coli with a reconstructed complete degradation pathway of 2,4-D to solve the problem of screening highly efficient degradation bacteria in this study. The results of fluorescence quantitative PCR demonstrated that all nine genes in the degradation pathway were successfully expressed in the engineered strain. The engineered strains can quickly and completely degrade 0.5 mM 2, 4-D within 6 h. Inspiring, the engineered strains grew with 2,4-D as the sole carbon source. By using the isotope tracing method, the metabolites of 2,4-D were found incorporated into the tricarboxylic acid cycle in the engineering strain. Scanning electron microscopy showed that 2,4-D had less damage on the engineered bacteria than the wild-type strain. Engineered strain can also rapidly and completely remedy 2,4-D pollution in natural water and soil. Assembling the metabolic pathways of pollutants through synthetic biology was an effective method to create pollutant-degrading bacteria for bioremediation.

[Research progress on the effects and mechanisms of electroacupuncture on radiation-induced brain injury].

Radiation-induced brain injury is a serious complication after cranio-cerebral radiotherapy, which affects the patient's quality of life and survival. A large number of studies have shown that various mechanisms such as neuronal apoptosis, blood-brain barrier damage, and synaptic dysfunction may be related to radiation-induced brain injury. Acupuncture has an important role in clinical rehabilitation of various brain injuries. As a new type of acupuncture, electroacupuncture has the characteristics of strong control ability, uniform and long-lasting stimulation, and is widely used in clinic. This article reviews the effects and mechanisms of electroacupuncture on radiation-induced brain injury, in order to provide a theoretical basis and experimental support for reasonable clinical application.

Astaxanthin mitigates oxidative stress caused by microplastics at the expense of reduced skin pigmentation in discus fish.

Microplastics (MPs) exposure generally triggers oxidative stress in fish species and vertebrate pigmentation is commonly influenced by oxidative stress, but MPs-induced oxidative stress on fish pigmentation and body color phenotype has not been reported. The aim of this study is to determine whether astaxanthin could mitigate the oxidative stress caused by MPs but at the expense of reduced skin pigmentation in fish. Here, we induced oxidative stress in discus fish (red skin color) by 40 or 400 items/L MPs under both astaxanthin (ASX) deprivation and supplementation. We found that lightness (L*) and redness (a*) values of fish skin were significantly inhibited by MPs under ASX deprivation. Moreover, MPs exposure significantly reduced ASX deposition in fish skin. The total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) activity in fish liver and skin were both significantly increased with the increase of MPs concentration, but content of glutathione (GSH) in fish skin showed a significant decrease. For ASX supplementation, the L*, a* values and ASX deposition were significantly improved by ASX, including the skin of MPs-exposed fish. The T-AOC and SOD levels changed non-significantly in fish liver and skin under the interaction of MPs and ASX, but ASX significantly reduced GSH content in fish liver. Biomarker response index indicated that ASX could improve the moderately altered antioxidant defense status of MPs-exposed fish. This study suggests that the oxidative stress caused by MPs was mitigated by ASX but at expense of reduced fish skin pigmentation.

Electrode Materials of Cobaltous Fluoride for Supercapacitor and Electrocatalysis Applications.

Herein, CoF2 was synthesized by a solvothermal method. The characterization results of the phase and morphology of the sample show that it was successfully synthesized and its morphology is composed of micron particles with uneven size and shape. The electrochemical test results of SCs in different electrolytes show that CoF2 has electrochemical activity only in alkaline electrolytes. Notably, the electrochemical behavior of CoF2 in LiOH solution is different from that in other alkaline solutions in that charge-discharge curve has a quasi-isosceles triangle shape and the CV curve has no obvious redox peak. That is, it has pseudocapacitance behavior in LiOH. Furthermore, CoF2 as catalyst for HER requires an overpotential of only 168 mV to obtain current density of 10 mA cm-2 and a Tafel slope of 116 mV dec-1 in 1 M KOH solution. This research provides a novel way to explore excellent performance electrode materials for SC and HER.

Genome-wide identification and skin expression of immunoglobulin superfamily in discus fish (Symphysodon aequifasciatus) reveal common genes associated with vertebrate lactation.

Discus Symphysodon spp. employs an unusual parental care behavior where fry feed on parental skin mucus after hatching. Studies on discus immunoglobulin superfamily (IgSF) especially during parental care are scarce. Here, a total of 518 IgSF members were identified based on discus genome and clustered into 12 groups, unevenly distributing on 30 linkage groups. A total of 92 pairs of tandem duplication and 40 pairs of segmental duplication that underwent purifying selection were identified. IgSF genes expressed differentially in discus skin during different care stages and between male and female parents. Specifically, the transcription of btn1a1, similar with mammalian lactation, increased after spawning, reached a peak when fry started biting on parents' skin mucus, and then decreased. The expression of btn2a1 and other immune members, e.g., nect4, fcl5 and cd22, were up-regulated when fry stopped biting on mucus. These results suggest the expression differentiation of IgSF genes in skin of discus fish during parental care.

Puerarin extends the lifespan of Drosophila melanogaster by activating autophagy.

Lifespan longevity has attracted increasing attention with societal development. To counter the effects of aging on longevity, we focused on the natural chemicals of plants. In this study, we investigated the effects of puerarin supplementation on the lifespan of Drosophila melanogaster. Puerarin supplementation significantly extended the lifespan of D. melanogaster at 60 µM and 120 µM by upregulating proteasome subunit beta 5 (prosbeta5) and sirtuin-1 (Sirt1). However, puerarin-induced longevity of male flies (F0 generation) may not be passed on to descendants. Additionally, a puerarin diet for 10 and 25 days did not influence the body weight and food intake of male Canton-S flies. Puerarin significantly improved the climbing ability, starvation resistance, and oxidation resistance of male flies by upregulating the expression of Shaker, catalase (CAT), superoxide dismutase 1 (SOD1), and Methuselah, and downregulating poly [ADP-ribose] polymerase (PARP-1) and major heat shock 70 kDa protein Aa (HSP70). Moreover, 120 µM puerarin supplementation for 25 days significantly increased adenosine 5' triphosphate (ATP) content by increasing adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) levels. Additionally, the puerarin diet for 25 days suppressed male fecundity in male flies by decreasing the levels of Bam and Punt. Mechanistically, puerarin enhanced lysosome-involved autophagy by promoting the expression of lysosome markers [ß-galactosidase and lysosomal associated membrane protein 1 (LAMP1)], and elevating the levels of autophagy-related genes, including autophagy-associated gene 1 (ATG1), ATG5, and ATG8b. However, puerarin decreased the phosphorylation of the target of rapamycin (TOR) protein. In conclusion, puerarin is a promising compound for improving the longevity of D. melanogaster by activating autophagy.

Phylogeny, transcriptional profile, and auxin-induced phosphorylation modification characteristics of conserved PIN proteins in Moso bamboo (Phyllostachys edulis).

Auxin polar transport is an important way for auxin to exercise its function, and auxin plays an irreplaceable role in the rapid growth of Moso bamboo. We identified and performed the structural analysis of PIN-FORMED auxin efflux carriers in Moso bamboo and obtained a total of 23 PhePIN genes from five gene subfamilies. We also performed chromosome localization and intra- and inter-species synthesis analysis. Phylogenetic analyses of 216 PIN genes showed that PIN genes are relatively conserved in the evolution of the Bambusoideae and have undergone intra-family segment replication in Moso bamboo. The PIN genes' transcriptional patterns showed that the PIN1 subfamily plays a major regulatory role. PIN genes and auxin biosynthesis maintain a high degree of consistency in spatial and temporal distribution. Phosphoproteomics analysis identified many phosphorylated protein kinases that respond to auxin regulation through autophosphorylation and phosphorylation of PIN proteins. The protein interaction network showed that there is a plant hormone interaction regulatory network with PIN protein as the core. We provide a comprehensive PIN protein analysis that complements the auxin regulatory pathway in Moso bamboo and paves the way for further auxin regulatory studies in bamboo.

Metformin attenuates fibroblast activation during pulmonary fibrosis by targeting S100A4 via AMPK-STAT3 axis.

Fibroblasts activation is a crucial process for development of fibrosis during idiopathic pulmonary fibrosis pathogenesis, and transforming growth factor (TGF)-ß1 plays a key regulatory role in fibroblast activation. It has been reported that metformin (MET) alleviated bleomycin (BLM)-induced pulmonary fibrosis (PF) by regulating TGF-ß1-induced fibroblasts activation, but the underlying mechanisms still deserve further investigations. In this study, MET blocked α-smooth muscle actin (α-SMA) accumulation in vivo accompanied with S100A4 expression and STAT3 phosphorylation inhibition, resulting in attenuating the progression of lung fibrosis after BLM administration. We determined that S100A4 plays critical roles in fibroblasts activation in vitro, evidenced by siRNA knockdown of S100A4 expression downregulated TGF-ß1 induced α-SMA production in Human fetal lung fibroblast (HFL1) cells. Importantly, we found for the first time that the expression of S100A4 in fibroblasts was regulated by STAT3. Stattic, an effective small molecule inhibitor of STAT3 phosphorylation, reduced S100A4 level in TGF-ß1- treated HFL1 cells accompanied with less α-SMA production. We further found that MET, which inhibits STAT3 phosphorylation by AMPK activation, also inhibits fibroblasts activation by targeting S100A4 in vitro. Together all these results, we conclude that S100A4 contributes to TGF-ß1- induced pro-fibrogenic function in fibroblasts activation, and MET was able to protect against TGF-ß1-induced fibroblasts activation and BLM-induced PF by down-regulating S100A4 expression through AMPK-STAT3 axis. These results provide a useful clue for a clinical strategy to prevent PF.

Clinical-radiomics nomogram for predicting esophagogastric variceal bleeding risk noninvasively in patients with cirrhosis.

BACKGROUND: Esophagogastric variceal bleeding (EGVB) is a serious complication of patients with decompensated cirrhosis and is associated with high mortality and morbidity. Early diagnosis and screening of cirrhotic patients at risk for EGVB is crucial. Currently, there is a lack of noninvasive predictive models widely available in clinical practice. AIM: To develop a nomogram based on clinical variables and radiomics to facilitate the noninvasive prediction of EGVB in cirrhotic patients. METHODS: A total of 211 cirrhotic patients hospitalized between September 2017 and December 2021 were included in this retrospective study. Patients were divided into training (n = 149) and validation (n = 62) groups at a 7:3 ratio. Participants underwent three-phase computed tomography (CT) scans before endoscopy, and radiomic features were extracted from portal venous phase CT images. The independent sample t-test and least absolute shrinkage and selection operator logistic regression were used to screen out the best features and establish a radiomics signature (RadScore). Univariate and multivariate analyses were performed to determine the independent predictors of EGVB in clinical settings. A noninvasive predictive nomogram for the risk of EGVB was built using independent clinical predictors and RadScore. Receiver operating characteristic, calibration, clinical decision, and clinical impact curves were applied to evaluate the model's performance. RESULTS: Albumin (P = 0.001), fibrinogen (P = 0.001), portal vein thrombosis (P = 0.002), aspartate aminotransferase (P = 0.001), and spleen thickness (P = 0.025) were selected as independent clinical predictors of EGVB. RadScore, constructed with five CT features of the liver region and three of the spleen regions, performed well in training (area under the receiver operating characteristic curve (AUC) = 0.817) as well as in validation (AUC = 0.741) cohorts. There was excellent predictive performance in both the training and validation cohorts for the clinical-radiomics model (AUC = 0.925 and 0.912, respectively). Compared with the existing noninvasive models such as ratio of aspartate aminotransferase to platelets and Fibrosis-4 scores, our combined model had better predictive accuracy with the Delong's test less than 0.05. The Nomogram had a good fit in the calibration curve (P > 0.05), and the clinical decision curve further supported its clinical utility. CONCLUSION: We designed and validated a clinical-radiomics nomogram able to noninvasively predict whether cirrhotic patients will develop EGVB, thus facilitating early diagnosis and treatment.

Liver Injury and Metabolic Dysregulation in Largemouth Bass (Micropterus salmoides) after Ammonia Exposure.

Elevated environmental ammonia leads to respiratory disorders and metabolic dysfunction in most fish species, and the majority of research has concentrated on fish behavior and gill function. Prior studies have rarely shown the molecular mechanism of the largemouth bass hepatic response to ammonia loading. In this experiment, 120 largemouth bass were exposed to total ammonia nitrogen of 0 mg/L or 13 mg/L for 3 and 7 days, respectively. Histological study indicated that ammonia exposure severely damaged fish liver structure, accompanied by increased serum alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase activity. RT-qPCR results showed that ammonia exposure down-regulated the expression of genes involved in glycogen metabolism, tricarboxylic acid cycle, lipid metabolism, and urea cycle pathways, whereas it up-regulated the expression of genes involved in gluconeogenesis and glutamine synthesis pathways. Thus, ammonia was mainly converted to glutamine in the largemouth bass liver during ammonia stress, which was rarely further used for urea synthesis. Additionally, transcriptome results showed that ammonia exposure also led to the up-regulation of the oxidative phosphorylation pathway and down-regulation of the mitogen-activated protein kinase signaling pathway in the liver of largemouth bass. It is possible that the energy supply of oxidative phosphorylation in the largemouth bass liver was increased during ammonia exposure, which was mediated by the MAPK signaling pathway.

Huashi baidu granule in the treatment of pediatric patients with mild coronavirus disease 2019: A single-center, open-label, parallel-group randomized controlled clinical trial.

Background: Since late February 2022, a wave of coronavirus disease 2019 (COVID-19) mainly caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant rapidly appeared in Shanghai, China. Traditional Chinese medicine treatment is recommended for pediatric patients; however, the safety and efficacy remain to be confirmed. We conducted a single-center, open-label, parallel-group randomized controlled trial to assess the efficacy and safety of a Chinese herb compound, Huashi Baidu granule (HSBDG) in pediatric patients with laboratory-confirmed mild COVID-19. Methods: 108 recruited children (aged 3-18 years) with laboratory-confirmed mild COVID-19 were randomly allocated 2:1 to receive oral HSBDG for five consecutive days (intervention group) and to receive compound pholcodine oral solution for five consecutive days (control group). The negative conversion time of SARS-CoV-2 nucleic acid and symptom scores were recorded. Results: The median negative conversion time of SARS-CoV-2 nucleic acid was significantly shorter in the intervention group than in the control group (median days [interquartile range (IQR)]: 3 [3-5] vs. 5 [3-6]; p = 0.047). The median total symptom score on day 3 was significantly lower in the intervention group than in the control group (median total symptom score [IQR]: 1 [0-2] vs. 2 [0-3]; p = 0.036). There was no significant differences in the frequency of antibiotic use and side effects between the two groups. Conclusion: HSBDG is a safe, effective oral Chinese herbal compound granule, which shows a good performance within the Omicron wave among pediatric patients.

Nocardiopsis changdeensis sp. nov., an endophytic actinomycete isolated from the roots of Eucommia ulmoides Oliv.

Strain Mg02T was isolated from roots of Eucommia ulmoides Oliv. collected from Changde City, Hunan Province, China. Strain Mg02T, which exhibited distinct chemotaxonomic characteristics of the genus Nocardiopsis: cell-wall chemotype III/C, i.e., meso-diaminopimelic acid as diagnostic amino acid in whole-cell hydrolysates and menaquinone MK-10 with variable degrees of saturation in the side chain as the predominant isoprenoid quinone, was investigated by a polyphasic approach to determine their taxonomic position. Sequence analysis of the 16S rRNA gene indicated that strain Mg02T is affiliated to the genus Nocardiopsis, having highest sequence similarity to Nocardiopsis flavescens CGMCC 4.5723T (99.1%) and <98.7% to other species of the genus Nocardiopsis with validly published names. Phylogenetic analysis of 16S rRNA gene indicated strain Mg02T formed a separate evolutionary clade, suggesting that it could be a novel Nocardiopsis species. Phylogenomic analysis showed that strain Mg02T was closely related to N. flavescens CGMCC 4.5723T and distinct from the latter according to the clustering patterns. The Average Nucleotide Identity and digital DNA-DNA hybridization values between strain Mg02T and N. flavescens CGMCC 4.5723T were far below the species-level thresholds. Based on phenotypic, phylogenetic and chemotaxonomic characteristics, we think that strain Mg02T should represent a novel Nocardiopsis species, for which the name Nocardiopsis changdeensis sp. nov. is proposed. The type strain is Mg02T (=MCCC 1K06174T = JCM 34709T).

A van der Waals heterojunction strategy to fabricate layer-by-layer single-molecule switch.

Single-molecule electronics offer a unique strategy for the miniaturization of electronic devices. However, the existing experiments are limited to the conventional molecular junctions, where a molecule anchors to the electrode pair with linkers. With such a rod-like configuration, the minimum size of the device is defined by the length of the molecule. Here, by incorporating a single molecule with two single-layer graphene electrodes, we fabricated layer-by-layer single-molecule heterojunctions called single-molecule two-dimensional van der Waals heterojunctions (M-2D-vdWHs), of which the sizes are defined by the thickness of the molecule. We controlled the conformation of the M-2D-vdWHs and the cross-plane charge transport through them with the applied electric field and established that they can serve as reversible switches. Our results demonstrate that the M-2D-vdWHs, as stacked from single-layer 2D materials and a single molecule, can respond to electric field stimulus, which promises a diverse class of single-molecule devices with unprecedented size.

The chromosome-level genome and key genes associated with mud-dwelling behavior and adaptations of hypoxia and noxious environments in loach (Misgurnus anguillicaudatus).

BACKGROUND: The loach (Misgurnus anguillicaudatus), the most widely distributed species of the family Cobitidae, displays a mud-dwelling behavior and intestinal air-breathing, inhabiting the muddy bottom of extensive freshwater habitats. However, lack of high-quality reference genome seriously limits the interpretation of the genetic basis of specialized adaptations of the loach to the adverse environments including but not limited to the extreme water temperature, hypoxic and noxious mud environment. RESULTS: This study generated a 1.10-Gb high-quality, chromosome-anchored genome assembly, with a contig N50 of 3.83 Mb. Multiple comparative genomic analyses found that proto-oncogene c-Fos (fos), a regulator of bone development, is positively selected in loach. Knockout of fos (ID: Mis0086400.1) led to severe osteopetrosis and movement difficulties, combined with the comparison results of bone mineral density, supporting the hypothesis that fos is associated with loach mud-dwelling behavior. Based on genomic and transcriptomic analysis, we identified two key elements involved in the intestinal air-breathing of loach: a novel gene (ID: mis0158000.1) and heat shock protein beta-1 (hspb1). The flavin-containing monooxygenase 5 (fmo5) genes, central to xenobiotic metabolism, undergone expansion in loach and were identified as differentially expressed genes in a drug stress trial. A fmo5-/- (ID: Mis0185930.1) loach displayed liver and intestine injury, indicating the importance of this gene to the adaptation of the loach to the noxious mud. CONCLUSIONS: Our work provides valuable insights into the genetic basis of biological adaptation to adverse environments.