Two superconducting states with broken time-reversal symmetry in FeSe1-xSx.

Iron-chalcogenide superconductors FeSe1-xSx possess unique electronic properties such as nonmagnetic nematic order and its quantum critical point. The nature of superconductivity with such nematicity is important for understanding the mechanism of unconventional superconductivity. A recent theory suggested the possible emergence of a fundamentally new class of superconductivity with the so-called Bogoliubov Fermi surfaces (BFSs) in this system. However, such an ultranodal pair state requires broken time-reversal symmetry (TRS) in the superconducting state, which has not been observed experimentally. Here, we report muon spin relaxation (µSR) measurements in FeSe1-xSx superconductors for 0 ≤ x ≤ 0.22 covering both orthorhombic (nematic) and tetragonal phases. We find that the zero-field muon relaxation rate is enhanced below the superconducting transition temperature Tc for all compositions, indicating that the superconducting state breaks TRS both in the nematic and tetragonal phases. Moreover, the transverse-field µSR measurements reveal that the superfluid density shows an unexpected and substantial reduction in the tetragonal phase (x > 0.17). This implies that a significant fraction of electrons remain unpaired in the zero-temperature limit, which cannot be explained by the known unconventional superconducting states with point or line nodes. The TRS breaking and the suppressed superfluid density in the tetragonal phase, together with the reported enhanced zero-energy excitations, are consistent with the ultranodal pair state with BFSs. The present results reveal two different superconducting states with broken TRS separated by the nematic critical point in FeSe1-xSx, which calls for the theory of microscopic origins that account for the relation between nematicity and superconductivity.

ImmCluster: an ensemble resource for immunology cell type clustering and annotations in normal and cancerous tissues.

Single-cell transcriptome has enabled the transcriptional profiling of thousands of immune cells in complex tissues and cancers. However, subtle transcriptomic differences in immune cell subpopulations and the high dimensionality of transcriptomic data make the clustering and annotation of immune cells challenging. Herein, we introduce ImmCluster (http://bio-bigdata.hrbmu.edu.cn/ImmCluster) for immunology cell type clustering and annotation. We manually curated 346 well-known marker genes from 1163 studies. ImmCluster integrates over 420 000 immune cells from nine healthy tissues and over 648 000 cells from different tumour samples of 17 cancer types to generate stable marker-gene sets and develop context-specific immunology references. In addition, ImmCluster provides cell clustering using seven reference-based and four marker gene-based computational methods, and the ensemble method was developed to provide consistent cell clustering than individual methods. Five major analytic modules were provided for interactively exploring the annotations of immune cells, including clustering and annotating immune cell clusters, gene expression of markers, functional assignment in cancer hallmarks, cell states and immune pathways, cell-cell communications and the corresponding ligand-receptor interactions, as well as online tools. ImmCluster generates diverse plots and tables, enabling users to identify significant associations in immune cell clusters simultaneously. ImmCluster is a valuable resource for analysing cellular heterogeneity in cancer microenvironments.

Exploring functional genes' correlation with (S)-equol concentration and new daidzein racemase identification.

With its estrogenic activity, (S)-equol plays an important role in maintaining host health and preventing estrogen-related diseases. Exclusive production occurs through the transformation of soy isoflavones by intestinal bacteria, but the reasons for variations in (S)-equol production among different individuals and species remain unclear. Here, fecal samples from humans, pigs, chickens, mice, and rats were used as research objects. The concentrations of (S)-equol, along with the genetic homology and evolutionary relationships of (S)-equol production-related genes [daidzein reductase (DZNR), daidzein racemase (DDRC), dihydrodaidzein reductase (DHDR), tetrahydrodaidzein reductase (THDR)], were analyzed. Additionally, in vitro functional verification of the newly identified DDRC gene was conducted. It was found that approximately 40% of human samples contained (S)-equol, whereas 100% of samples from other species contained (S)-equol. However, there were significant variations in (S)-equol content among the different species: rats > pigs > chickens > mice > humans. The distributions of the four genes displayed species-specific patterns. High detection rates across various species were exhibited by DHDR, THDR, and DDRC. In contrast, substantial variations in detection rates among different species and individuals were observed with respect to DZNR. It appears that various types of DZNR may be associated with different concentrations of (S)-equol, which potentially correspond to the regulatory role during (S)-equol synthesis. This enhances our understanding of individual variations in (S)-equol production and their connection with functional genes in vitro. Moreover, the newly identified DDRC exhibits higher potential for (S)-equol synthesis compared to the known DDRC, providing valuable resources for advancing in vitro (S)-equol production. IMPORTANCE: (S)-equol ((S)-EQ) plays a crucial role in maintaining human health, along with its known capacity to prevent and treat various diseases, including cardiovascular diseases, metabolic syndromes, osteoporosis, diabetes, brain-related diseases, high blood pressure, hyperlipidemia, obesity, and inflammation. However, factors affecting individual variations in (S)-EQ production and the underlying regulatory mechanisms remain elusive. This study examines the association between functional genes and (S)-EQ production, highlighting a potential correlation between the DZNR gene and (S)-EQ content. Various types of DZNR may be linked to the regulation of (S)-EQ synthesis. Furthermore, the identification of a new DDRC gene offers promising prospects for enhancing in vitro (S)-EQ production.

High expression of small nucleolar host gene RNA may predict poor prognosis of Hepatocellular carcinoma, based on systematic reviews and meta-analyses.

BACKGROUND: The prognosis of patients with hepatocellular cancer is substantially correlated with the abnormal expression of growing long non-coding RNA small nucleolar host gene RNA (SNHG) families in liver cancer tissues. This study aimed to examine the relationship between SNHG expression and liver cancer prognosis. METHODS: After searching six internet databases, pertinent manuscripts were found based on inclusion and exclusion criteria. To determine whether SNHG expression levels affect liver cancer prognosis, raw data were collected and hazard ratios (HRs) and odds ratios (ORs) were calculated. The results were examined for potential publication bias using the sensitivity analysis and Beeg's test. RESULTS: Most SNHG family members were up-regulated in liver cancer tissues. High SNHG expression predicts poor liver cancer outcomes of, including overall survival (OS) (HR: 1.697, 95% confidence interval [CI]: 1.373-2.021), especially SNHG5 (the HR of OS is 4.74, 95%CI range from 1.35 to 6.64), progression-free survival (HR: 1.85, 95% CI: 1.25-2.73), tumor, node, metastasis (TNM) stage (OR: 1.696, 95% CI: 1.436-2.005), lymph node metastasis (OR: 2.383, 95% CI: 1.098-5.173), and tumor size (OR: 1363, 95% CI: 1.165-1.595). The OS results were found to be reliable and robust, as indicated by the sensitivity analysis. Additionally, Beeg's test demonstrated the absence of any potential publication bias for each result. CONCLUSION: In liver cancer tissues, most SNHGs are highly expressed, which may signal poor prognosis. SNHG has the potential to be an intriguing predictive marker and a prospective therapeutic target for liver cancer.

A Neutral Polysaccharide from Medicago Sativa L.: Structural Properties and Hypoglycemic Activity In Vitro and In Vivo.

Medicago sativa polysaccharides (MSPs) are beneficial compounds extracted from Medicago sativa L. that exhibit multiple medicinal activities. However, little is known about their hypoglycemic effects. In this study, MSP-II-a, a neutral polysaccharide with an Mw of 4.3×104 Da, was isolated and purified from M. sativa L. Monosaccharide composition analysis determined that MSP-II-a was composed of arabinose, glucose, galactose, mannose, rhamnose, and xylose in a molar ratio of 2.1 : 4.0 : 1.1:0.4 : 1.4 : 1.1. Structural characterization of MSP-II was performed using a combination of methylation analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy. The results showed that MSP-II-a was mainly comprised of 1,4-p-Glc, 1,3,4-Rha, and 1,3-p-Gal glycosidic linkages, revealing a mesh-like texture with irregular blade shapes. In vitro assays demonstrated that MSP-II-a, at concentrations of 200 and 400 µg/mL, promoted glucose uptake in insulin-resistant 3T3-L1 adipocytes. In vivo studies have shown that MSP-II-a significantly alleviates insulin resistance by reducing fasting blood glucose levels and increasing hepatic glycogen synthesis in HFD/STZ-induced diabetic mice. These findings revealed that MSP-II-a is a promising source of bioactive polysaccharides with potential hypoglycemic activity.

Xylarkarynone A and B: Two Bioactive Eremophilane Sesquiterpenes from Xylaria sp. HHY-2.

A new compound xylarkarynone A (1), a first reported natural product compound xylarkarynone B (2) and eight known compounds (3-10) were isolated from Xylaria sp. HHY-2. Their structures were elucidated by spectroscopic methods, DP4+ probability analyses and electronic circular dichroism (ECD) calculations. The bioactivities of isolated compounds were assayed. Compound 1 exhibited obvious activity against A549 cells with an IC50 value of 6.12±0.28 µM. Additionally, compound 1 showed moderate antifungal activities against Plectosphaerella cucumerina and Aspergillus niger with minimum inhibitory concentrations (MICs) of both 16 µg/mL, which was at the same grade with positive control nystatin. Most compounds exhibited varying degrees of inhibitory activity against P. cucumerina, indicating that Xylaria sp. has potential as inhibitors against P. cucumerina.

Single-Cell Transcriptomics Reveals Cellular Heterogeneity and Drivers in Serrated Pathway-Driven Colorectal Cancer Progression.

Serrated lesions are common precancerous pathways in colorectal cancer (CRC), but the process by which they progress to malignancy remains unclear. We aimed to elucidate this progression through a single-cell RNA landscape. We conducted single-cell RNA sequencing on three normal colonic tissues and fifteen SLs (including HPs, SSLs, SSLD, and TSAs) and integrated these data with datasets containing tumor samples. We identified three invasive malignant epithelial cell subtypes related to CRC progression: SLC1, SLC2, and tumor cell. SLC1, specific to SSLs, is involved in cell proliferation and shows a continuum of malignancy in gene expression. TSA-specific SLC2 exhibited FOXQ1 upregulation and active EMT, indicating invasiveness. The trajectory analysis showed that HPs do not progress to cancer, and different SL types are linked to the MSI status of advanced CRCs. We validated molecular drivers in premalignant lesions and later carcinogenesis. In the tumor microenvironment, CAF and pre-CAF fibroblast subtypes associated with progression were identified. During the premalignant stage, SLC1 triggered CD8+ T cell responses, while at the advanced stage, CAFs promoted tumor invasion and metastasis via FN1-CD44, influencing tumor progression and the treatment response. Our findings highlight transcriptional changes across serrated pathway stages, aiding in early CRC diagnosis and treatment.

TC2N Promotes Cell Proliferation and Metastasis in Hepatocellular Carcinoma by Targeting the Wnt/ß-Catenin Signaling Pathway.

Hepatocellular carcinoma (HCC), one of the most prevalent types of cancer worldwide, has an exceedingly poor prognosis. Tandem C2 domain nuclear protein (TC2N) has been implicated in tumorigenesis and serves as an oncogene or tumor suppressor in different types of cancer. Here, we explore the possible regulatory activities and molecular mechanisms of TC2N in HCC progression. However, TC2N expression was significantly upregulated in HCC tissues and hepatoma cell lines, and this upregulation was positively correlated with tumor progression in HCC patients. The ectopic overexpression of TC2N accelerated the proliferation, migration, and invasion of HCC cells, whereas its knockdown showed the opposite effects. Bioinformatics analysis showed that TC2N participates in the regulation of the Wnt/ß-catenin signaling pathway. Mechanistically, TC2N activated the Wnt/ß-catenin signaling pathway by regulating the expression levels of ß-catenin and its downstream targets CyclinD1, MMP7, c-Myc, c-Jun, AXIN2, and glutamine synthase. Furthermore, the deletion of ß-catenin effectively neutralized the regulation of TC2N in HCC proliferation and metastasis. Overall, this study showed that TC2N promotes HCC proliferation and metastasis by activating the Wnt/ß-catenin signaling pathway, indicating that TC2N might be a potential molecular target for the treatment of HCC.

Isolation and genomic characterization of Vmp-1 using Vibrio mimicus as the host: A novel virulent bacteriophage capable of cross-species lysis against three Vibrio spp.

Vibrio mimicus is a zoonotic pathogen that is widely distributed in aquatic habitats/environments (marine coastal water, estuaries, etc). The development of biocontrol agents for V. mimicus is imperative for the prevention and control of aquatic animal diseases and human food-borne infections. In this study, a broad-spectrum bacteriophage Vmp-1 was isolated from dealt aquatic product in a local market by double-layer agar plate method using V. mimicus CICC21613 as the host bacteria. Results indicated that Vmp-1, which belongs to the family Podoviridae, showed good pH tolerance (pH 3.0-12.0) and thermal stability (30-50 °C). The optimal multiplicity of infection (MOI) of Vmp-1 was 0.001 for a 20-min incubation and 100-min lysis period. Vmp-1 effectively controlled V. mimicus CICC21613 in LBS model (MOI = 0.0001, 0.001, 0.01, 0.1, 1) within 8 h. The full length of the Vmp-1 genome was 43,312 bp, with average GC content of 49.5%, and a total of 44 protein-coding regions. This study provides a novel phage strain that has the highest homology with vB_VpP_HA5 (GenBank: OK585159.1, 95.96%) for the development of biocontrol agents for V. mimicus.

Rapid genotyping of 32 insertion/deletion panel for human identification using fluorogenic probes-based multiplex real-time PCR.

BACKGROUND: Insertion and deletion (InDel) polymorphisms have considerable potential in the field of forensic genetics because of their low mutation rate and small amplicons. At present, InDel polymorphisms detection based on the technique of capillary electrophoresis is the main technique used in forensic DNA laboratory. However, this method is complicated and time-consuming, and is not suitable for rapid on-site paternity and personal identification. Next-generation sequencing analysis of InDels polymorphisms requires expensive instruments, large upfront reagent and supply costs, computational requirements and complex bioinformatics, increased the time to obtain results. Thus, there is an urgent need to establish a method to provide reliable, rapid, sensitive and economical genotyping for InDels. METHOD: A rapid InDels (32 InDels) panel was established using fluorogenic probes-based multiplex real-time PCR with microfluidic test cartridge and portable real-time PCR instrument. Then, we performed several validation studies including concordance, accuracy, sensitivity, stability, species specificity. RESULTS: It showed that the complete genotypes could be obtained from ≥100 pg of input DNA and from a series of challenging samples with high accuracy and specificity within 90 min. CONCLUSION: This method provides a rapid and cost-effective solution for InDels genotyping and personal identification in portable format.

Risk factors of multidrug-resistant bacteria infection in patients with ventilator-associated pneumonia: A systematic review and meta-analysis.

BACKGROUND: Multidrug-resistant (MDR) bacteria-induced VAP often has high lethality. We present this systematic review and meta-analysis to assess the risk factors for MDR bacterial infection in patients with VAP. METHODS: PubMed, EMBASE, Web of Science, and Cochrane Library were searched for studies regarding MDR bacterial infection in VAP patients, from Jan 1996 to Aug 2022. Study selection, data extraction, and quality assessment of included studies were conducted by two reviewers independently, and potential risk factors for MDR bacterial infection were identified. RESULTS: Meta-analysis showed that the score of the Acute Physiology and Chronic Health Evaluation II (APACHE-II) [OR = 1.009, 95% (CI 0.732, 1.287)], Simplified Acute Physiology Score II (SAPS-II) [OR = 2.805, 95%CI (0.854, 4.755)], length of hospital-stay before VAP onset (days) [OR = 2.639, 95%CI (0.387, 4.892)], in-ICU duration [OR = 3.958, 95%CI (0.894, 7.021)], Charlson index [OR = 1.000, 95%CI (0.889, 1.111)], overall hospital-stay [OR = 20.742, 95%CI (18.894, 22.591)], Medication of Quinolones [OR = 2.017, 95%CI (1.339, 3.038)], medication of carbapenems [OR = 3.527, 95%CI (2.476, 5.024)], combination of more than 2 prior antibiotics [OR = 3.181, 95%CI (2.102, 4.812)], and prior use of antibiotics [OR 2.971, 95%CI (2.001, 4.412)] were independent risk factors of MDR bacterial infection in VAP patients. Diabetes and mechanical ventilation duration before VAP onset showed no association with risk for MDR bacterial infection. CONCLUSIONS: This study has identified 10 risk factors associated with MDR bacterial infection in VAP patients. Identification of these factors would be able to facilitate the treatment and prevention of MDR bacterial infection in clinical practice.

TRIM31 promotes the progression of oral squamous cell carcinoma through upregulating AKT phosphorylation and subsequent cellular glycolysis.

The regulation of protein kinase B (AKT) phosphorylation by Tripartite motif-containing protein 31 (TRIM31) is implicated as an essential mechanism in the progression of many malignant tumors. Nevertheless, the function of the TRIM31/AKT pathway in oral squamous cell carcinoma (OSCC) remains elusive. Here, immunohistochemistry analysis of human OSCC tissue microarrays indicated significantly higher levels of TRIM31 and phosphorylated AKT (p-AKT) in OSCC tumors than in adjacent tissue samples. Also, we detected a positive association between TRIM31 expression and clinical OSCC development. In in vitro studies, TRIM31 knockdown severely impaired OSCC cell growth, invasion, and migration. By contrast, TRIM31 overexpression improved these cell behaviors, while subsequent AKT inhibition abrogated the effect. In vivo tumorigenesis experiments using nude mice also validated the effects of TRIM31/AKT signaling in tumor growth. Furthermore, TRIM31 upregulation facilitated glucose uptake, as well as lactate and adenosine triphosphate production of OSCC cells, while such positive effects on glycolysis and malignant cell phenotypes were reversed by treatment with AKT or glycolysis inhibitors. In conclusion, TRIM31 may improve OSCC progression by enhancing AKT phosphorylation and subsequent glycolysis. Hence, TRIM31 has the potential as a treatment target in OSCC.

A Comprehensive Review on Adsorption, Photocatalytic and Chemical Degradation of Dyes and Nitro-Compounds over Different Kinds of Porous and Composite Materials.

Dye and nitro-compound pollution has become a significant issue worldwide. The adsorption and degradation of dyes and nitro-compounds have recently become important areas of study. Different methods, such as precipitation, flocculation, ultra-filtration, ion exchange, coagulation, and electro-catalytic degradation have been adopted for the adsorption and degradation of these organic pollutants. Apart from these methods, adsorption, photocatalytic degradation, and chemical degradation are considered the most economical and efficient to control water pollution from dyes and nitro-compounds. In this review, different kinds of dyes and nitro-compounds, and their adverse effects on aquatic organisms and human beings, were summarized in depth. This review article covers the comprehensive analysis of the adsorption of dyes over different materials (porous polymer, carbon-based materials, clay-based materials, layer double hydroxides, metal-organic frameworks, and biosorbents). The mechanism and kinetics of dye adsorption were the central parts of this study. The structures of all the materials mentioned above were discussed, along with their main functional groups responsible for dye adsorption. Removal and degradation methods, such as adsorption, photocatalytic degradation, and chemical degradation of dyes and nitro-compounds were also the main aim of this review article, as well as the materials used for such degradation. The mechanisms of photocatalytic and chemical degradation were also explained comprehensively. Different factors responsible for adsorption, photocatalytic degradation, and chemical degradation were also highlighted. Advantages and disadvantages, as well as economic cost, were also discussed briefly. This review will be beneficial for the reader as it covers all aspects of dye adsorption and the degradation of dyes and nitro-compounds. Future aspects and shortcomings were also part of this review article. There are several review articles on all these topics, but such a comprehensive study has not been performed so far in the literature.

[Effects of Rehmanniae Radix and Rehmanniae Radix Praeparata on proteomics and autophagy in mice with type 2 diabetes mellitus induced by high-fat diet coupled with streptozotocin].

To compare the pancreatic proteomics and autophagy between Rehmanniae Radix-and Rehmanniae Radix Praeparata-treated mice with type 2 diabetes mellitus(T2DM). The T2DM mouse model was established by high-fat diet coupled with streptozotocin(STZ, intraperitoneal injection, 100 mg·kg~(-1), once a day for three consecutive days). The mice were then randomly assigned into a control group, low-(5 g·kg~(-1)) and high-dose(15 g·kg~(-1)) Rehmanniae Radix groups, low-(150 mg·kg~(-1)) and high-dose(300 mg·kg~(-1)) catalpol groups, low-(5 g·kg~(-1)) and high-dose(15 g·kg~(-1)) Rehmanniae Radix Praeparata groups, low-(150 mg·kg~(-1)) and high-dose(300 mg·kg~(-1)) 5-hydroxymethyl furfuraldehyde(5-HMF) groups, and a metformin(250 mg·kg~(-1)) group. In addition, a normal group was also set and each group included 8 mice. The pancreas was collected after four weeks of administration and proteomics tools were employed to study the effects of Rehmanniae Radix and Rehmanniae Radix Praeparata on protein expression in the pancreas of T2DM mice. The expression levels of proteins involved in autophagy, inflammation, and oxidative stress response in the pancreatic tissues of T2DM mice were determined by western blotting, immunohistochemical assay, and transmission electron microscopy. The results showed that the differential proteins between the model group and Rehmanniae Radix/Rehmanniae Radix Prae-parata group were enriched in 7 KEGG pathways, such as autophagy-animal, which indicated that the 7 pathways may be associated with T2DM. Compared with the control group, drug administration significantly up-regulated the expression levels of beclin1 and phosphorylated mammalian target of rapamycin(p-mTOR)/mTOR and down-regulated those of the inflammation indicators, Toll-like receptor-4(TLR4) and Nod-like receptor protein 3(NLRP3), in the pancreas of T2DM mice, and Rehmanniae Radix showed better performance. In addition, the expression levels of inducible nitric oxide synthase(iNOS), nuclear factor erythroid 2-related factor 2(Nrf2), and heine oxygenase-1(HO-1) in the pancreas of T2DM mice were down-regulated after drug administration, and Rehmanniae Radix Praeparata demonstrated better performance. The results indicate that both Rehmanniae Radix and Rehmanniae Radix Praeparata can alleviate the inflammatory symptoms, reduce oxidative stress response, and increase the autophagy level in the pancreas of T2DM mice, while they exert the effect on different autophagy pathways.

Process of Forensic Medicine in DNA Identification of Aged Human Remains.

Skeleton and teeth are important biological samples. Due to their special structure and strong ability to resist degradation, they are ideal biological materials to retain DNA under natural condition. In many cases, such as historical figure identification, aged skeleton and teeth are usually the only biological samples. However, their DNA is in a state of trace, damage and degradation to different degrees, which requires special experimental treatment to achieve identification. This paper reviews the sample selection, DNA extraction, DNA enrichment and analysis approaches based on relevant research reports in recent years, aiming to promote the further development and improvement of the aged skeleton and teeth identification system.

Phosphoric Acid-Catalyzed Enantioselective Synthesis of Axially Chiral Anthrone-based Compounds.

Anthrones and analogues are structural cores shared by diverse pharmacologically active natural and synthetic compounds. The sp2 -rich nature imposes inherent obstruction to introduce stereogenic element onto the tricyclic aromatic backbone. In our pursuit to expand the chemical space of axial chirality, a novel type of axially chiral anthrone-derived skeleton was discovered. This work establishes oxime ether as suitable functionality to furnish axial chirality on symmetric anthrone skeletons through stereoselective condensation of the carbonyl entity with long-range chirality control. The enantioenriched anthrones could be elaborated into dibenzo-fused seven-membered N-heterocycles containing well-defined stereogenic center via Beckmann rearrangement with axial-to-point chirality conversion.

Intermetallic PtFe Electrocatalysts for the Oxygen Reduction Reaction: Ordering Degree-Dependent Performance.

Platinum-based atomically ordered alloys (i.e., intermetallic compounds) have distinct advantages over disordered solid solution counterparts in boosting the cathodic oxygen-reduction reaction (ORR) in proton-exchange-membrane fuel cells. Nevertheless, the pivotal role of ordering degree of intermetallic catalysts in promoting ORR performance has been ignored heavily so far, probably owing to the lack of synthetic routes for controlling the ordering degree, especially for preparing highly ordered intermetallic catalysts. Herein, a family of intermetallic PtFe catalysts with similar particle size of 3-4 nm but varied ordering degree in a wide range of 10-70% are prepared. After constructing the PtFe/Pt core/shell structure with around 3 Pt-layer skin, a positive correlation between the ordering degree of the intermetallic catalysts and their ORR activity and durability is identified. Notably, the highly ordered PtFe/Pt catalyst exhibits a high mass activity of 0.92 A mgPt -1 at 0.9 ViR-corrected as cathode catalyst in H2 -O2 fuel cell, with only 24% loss after accelerated durability tests. The ordering degree-dependent performance can be ascribed to the compressive strain effect induced by the intermetallic PtFe core with smaller lattice parameters, and the more thermodynamically stable intermetallic structure compared to disordered alloys.

d-Alanine Metabolism via d-Ala Aminotransferase by a Marine Gammaproteobacterium, Pseudoalteromonas sp. Strain CF6-2.

As the most abundant d-amino acid (DAA) in the ocean, d-alanine (d-Ala) is a key component of peptidoglycan in the bacterial cell wall. However, the underlying mechanisms of bacterial metabolization of d-Ala through the microbial food web remain largely unknown. In this study, the metabolism of d-Ala by marine bacterium Pseudoalteromonas sp. strain CF6-2 was investigated. Based on genomic, transcriptional, and biochemical analyses combined with gene knockout, d-Ala aminotransferase was found to be indispensable for the catabolism of d-Ala in strain CF6-2. Investigation on other marine bacteria also showed that d-Ala aminotransferase gene is a reliable indicator for their ability to utilize d-Ala. Bioinformatic investigation revealed that d-Ala aminotransferase sequences are prevalent in genomes of marine bacteria and metagenomes, especially in seawater samples, and Gammaproteobacteria represents the predominant group containing d-Ala aminotransferase. Thus, Gammaproteobacteria is likely the dominant group to utilize d-Ala via d-Ala aminotransferase to drive the recycling and mineralization of d-Ala in the ocean. IMPORTANCE As the most abundant d-amino acid in the ocean, d-Ala is a component of the marine DON (dissolved organic nitrogen) pool. However, the underlying mechanism of bacterial metabolization of d-Ala to drive the recycling and mineralization of d-Ala in the ocean is still largely unknown. The results in this study showed that d-Ala aminotransferase is specific and indispensable for d-Ala catabolism in marine bacteria and that marine bacteria containing d-Ala aminotransferase genes are predominantly Gammaproteobacteria widely distributed in global oceans. This study reveals marine d-Ala-utilizing bacteria and the mechanism of their metabolization of d-Ala. The results shed light on the mechanisms of recycling and mineralization of d-Ala driven by bacteria in the ocean, which are helpful in understanding oceanic microbial-mediated nitrogen cycle.

Optimization and performance evaluation of double-stranded probe in real-time PCR.

BACKGROUND: TaqMan probe-based real-time PCR (qPCR/RT-qPCR) has been widely used in various fields because of its high sensitivity and specificity. However, TaqMan probes are associated with a relatively higher background signal, and hence negatively affect the detection results. METHODS: Double-stranded probes (DSPs) were designed for the high sensitive detection of hepatitis B virus (HBV) DNA and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA using qPCR/RT-qPCR. Old DSPs (ODSPs) consist of different lengths of positive and negative strands with complementary oligonucleotides. We systematically optimized ODSPs length, the free energy of hybridization (ΔG) between complementary oligonucleotides, and the length of sticky ends, and the novel DSPs performances were evaluated in comparison with other types of probes. RESULTS: By using similar length positive and negative strands, controlling ΔG between complementary oligonucleotides to approximately -30 kcal/mol, and maintaining the sticky end length at 4-6 nt, the analytical performances of DSPs were significantly improved. Compared with other types of probes, DSPs are advantageous in fluorescence signal intensity and sensitivity. CONCLUSION: DSPs can further improve the detection sensitivity and the detection rate of low-concentration samples in molecular diagnosis.

A mild one-pot transformation of nitroalkanes to ketones or aldehydes via a visible-light photocatalysis-hydrolysis sequence.

Using a visible-light photoredox catalysis strategy with household decorative blue LEDs and the additives Et3N and DIPEA, as well as the subsequent hydrolysis sequence, a mild one-pot process for the direct transformation of nitroalkanes to the corresponding ketones and aldehydes, constituting a Nef-like reaction, has been developed. It is worth noting that by using an appropriate photocatalyst (e.g., [Ir(dtbbpy)(ppy)2]PF6) and the extra additive Et3N with the combination of DIPEA and Mg(ClO4)2 in i-PrOH (instead of CH3CN), the transformation of nitroalkanes to the corresponding oximes, rather than nitrones, can be markedly more effective. The oximes can then be hydrolyzed to ketones by reaction with CuCl2·2H2O in a pH 7 buffer solution. This process is appealing because of the benefits of efficient conversion, mild conditions, high yields, and general applicability to compounds with a wide range of labile functional groups.