The NADH recycling enzymes TsaC and TsaD regenerate reducing equivalents for Rieske oxygenase chemistry.

Many microorganisms use both biological and nonbiological molecules as sources of carbon and energy. This resourcefulness means that some microorganisms have mechanisms to assimilate pollutants found in the environment. One such organism is Comamonas testosteroni, which metabolizes 4-methylbenzenesulfonate and 4-methylbenzoate using the TsaMBCD pathway. TsaM is a Rieske oxygenase, which in concert with the reductase TsaB consumes a molar equivalent of NADH. Following this step, the annotated short-chain dehydrogenase/reductase and aldehyde dehydrogenase enzymes TsaC and TsaD each regenerate a molar equivalent of NADH. This co-occurrence ameliorates the need for stoichiometric addition of reducing equivalents and thus represents an attractive strategy for integration of Rieske oxygenase chemistry into biocatalytic applications. Therefore, in this work, to overcome the lack of information regarding NADH recycling enzymes that function in partnership with Rieske non-heme iron oxygenases (Rieske oxygenases), we solved the X-ray crystal structure of TsaC to a resolution of 2.18 Å. Using this structure, a series of substrate analog and protein variant combination reactions, and differential scanning fluorimetry experiments, we identified active site features involved in binding NAD+ and controlling substrate specificity. Further in vitro enzyme cascade experiments demonstrated the efficient TsaC- and TsaD-mediated regeneration of NADH to support Rieske oxygenase chemistry. Finally, through in-depth bioinformatic analyses, we illustrate the widespread co-occurrence of Rieske oxygenases with TsaC-like enzymes. This work thus demonstrates the utility of these NADH recycling enzymes and identifies a library of short-chain dehydrogenase/reductase enzyme prospects that can be used in Rieske oxygenase pathways for in situ regeneration of NADH.

Leveraging a Structural Blueprint to Rationally Engineer the Rieske Oxygenase TsaM.

Rieske nonheme iron oxygenases use two metallocenters, a Rieske-type [2Fe-2S] cluster and a mononuclear iron center, to catalyze oxidation reactions on a broad range of substrates. These enzymes are widely used by microorganisms to degrade environmental pollutants and to build complexity in a myriad of biosynthetic pathways that are industrially interesting. However, despite the value of this chemistry, there is a dearth of understanding regarding the structure-function relationships in this enzyme class, which limits our ability to rationally redesign, optimize, and ultimately exploit the chemistry of these enzymes. Therefore, in this work, by leveraging a combination of available structural information and state-of-the-art protein modeling tools, we show that three "hotspot" regions can be targeted to alter the site selectivity, substrate preference, and substrate scope of the Rieske oxygenase p-toluenesulfonate methyl monooxygenase (TsaM). Through mutation of six to 10 residues distributed between three protein regions, TsaM was engineered to behave as either vanillate monooxygenase (VanA) or dicamba monooxygenase (DdmC). This engineering feat means that TsaM was rationally engineered to catalyze an oxidation reaction at the meta and ortho positions of an aromatic substrate, rather than its favored native para position, and that TsaM was redesigned to perform chemistry on dicamba, a substrate that is not natively accepted by the enzyme. This work thus contributes to unlocking our understanding of structure-function relationships in the Rieske oxygenase enzyme class and expands foundational principles for future engineering of these metalloenzymes.

Neuroprotective Alkamides from the Aerial Parts of Achillea alpina L.

Three new alkamides, achilleamide B-D (1-3) along with five known alkamides (4-8) were isolated from the aerial parts of Achillea alpina L. Structures were elucidated by spectroscopic analysis. Modified Mosher's method and electronic circular dichroism (ECD) calculations were introduced for the absolute configuration of 3. The neuroprotective effects of all the compounds were evaluated by 6-hydroxydopamine (6-OHDA)-induced cell death in human neuroblastoma SH-SY5Y cells, with concentration for 50 % of maximal effect (EC50 ) values of 3.16-24.75 µM, and the structure-activity relationship was conducted.

Identification of key genes as predictive biomarkers for osteosarcoma metastasis using translational bioinformatics.

BACKGROUND: Osteosarcoma (OS) metastasis is the most common cause of cancer-related mortality, however, no sufficient clinical biomarkers have been identified. In this study, we identified five genes to help predict metastasis at diagnosis. METHODS: We performed weighted gene co-expression network analysis (WGCNA) to identify the most relevant gene modules associated with OS metastasis. An important machine learning algorithm, the support vector machine (SVM), was employed to predict key genes for classifying the OS metastasis phenotype. Finally, we investigated the clinical significance of key genes and their enriched pathways. RESULTS: Eighteen modules were identified in WGCNA, among which the pink, red, brown, blue, and turquoise modules demonstrated good preservation. In the five modules, the brown and red modules were highly correlated with OS metastasis. Genes in the two modules closely interacted in protein-protein interaction networks and were therefore chosen for further analysis. Genes in the two modules were primarily enriched in the biological processes associated with tumorigenesis and development. Furthermore, 65 differentially expressed genes were identified as common hub genes in both WGCNA and protein-protein interaction networks. SVM classifiers with the maximum area under the curve were based on 30 and 15 genes in the brown and red modules, respectively. The clinical significance of the 45 hub genes was analyzed. Of the 45 genes, 17 were found to be significantly correlated with survival time. Finally, 5/17 genes, including ADAP2 (P = 0.0094), LCP2 (P = 0.013), ARHGAP25 (P = 0.0049), CD53 (P = 0.016), and TLR7 (P = 0.04) were significantly correlated with the metastatic phenotype. In vitro verification, western blotting, wound healing analyses, transwell invasion assays, proliferation assays, and colony formation assays indicated that ARHGAP25 promoted OS cell migration, invasion, proliferation, and epithelial-mesenchymal transition. CONCLUSION: We identified five genes, namely ADAP2, LCP2, ARHGAP25, CD53, and TLR7, as candidate biomarkers for the prediction of OS metastasis; ARHGAP25 inhibits MG63 OS cell growth, migration, and invasion in vitro, indicating that ARHGAP25 can serve as a promising specific and prognostic biomarker for OS metastasis.

Loss of high-temperature requirement protein A2 protease activity induces mitonuclear imbalance via differential regulation of mitochondrial biogenesis in sarcopenia.

Cellular homeostasis requires tight coordination between nucleus and mitochondria, organelles that each possesses their own genomes. Disrupted mitonuclear communication has been found to be implicated in many aging processes. However, little is known about mitonuclear signaling regulator in sarcopenia which is a major contributor to the risk of poor health-related quality of life, disability, and premature death in older people. High-temperature requirement protein A2 (HtrA2/Omi) is a mitochondrial protease and plays an important role in mitochondrial proteostasis. HtrA2mnd2(-/-) mice harboring protease-deficient HtrA2/Omi Ser276Cys missense mutants exhibit premature aging phenotype. Additionally, HtrA2/Omi has been established as a signaling regulator in nervous system and tumors. We therefore asked whether HtrA2/Omi participates in mitonuclear signaling regulation in muscle degeneration. Using motor functional, histological, and molecular biological methods, we characterized the phenotype of HtrA2mnd2(-/-) muscle. Furthermore, we isolated the gastrocnemius muscle of HtrA2mnd2(-/-) mice and determined expression of genes in mitochondrial unfolded protein response (UPRmt ), mitohormesis, electron transport chain (ETC), and mitochondrial biogenesis. Here, we showed that HtrA2/Omi protease deficiency induced denervation-independent skeletal muscle degeneration with sarcopenia phenotypes. Despite mitochondrial hypofunction, upregulation of UPRmt and mitohormesis-related genes and elevated total reactive oxygen species (ROS) production were not observed in HtrA2mnd2(-/-) mice, contrary to previous assumptions that loss of protease activity of HtrA2/Omi would lead to mitochondrial dysfunction as a result of proteostasis disturbance and ROS burst. Instead, we showed that HtrA2/Omi protease deficiency results in different changes between the expression of nuclear DNA- and mitochondrial DNA-encoded ETC subunits, which is in consistent with their transcription factors, nuclear respiratory factors 1 and 2, and coactivator peroxisome proliferator-activated receptor γ coactivator 1α. These results reveal that loss of HtrA2/Omi protease activity induces mitonuclear imbalance via differential regulation of mitochondrial biogenesis in sarcopenia. The novel mechanistic insights may be of importance in developing new therapeutic strategies for sarcopenia.

Control of Protein Conformation and Orientation on Graphene.

Graphene-based biosensors have attracted considerable attention due to their advantages of label-free detection and high sensitivity. Many such biosensors utilize noncovalent van der Waals force to attach proteins onto graphene surface while preserving graphene's high conductivity. Maintaining the protein structure without denaturation/substantial conformational change and controlling proper protein orientation on the graphene surface are critical for biosensing applications of these biosensors fabricated with proteins on graphene. Based on the knowledge we obtained from our previous experimental study and computer modeling of amino acid residual level interactions between graphene and peptides, here we systemically redesigned an important protein for better conformational stability and desirable orientation on graphene. In this paper, immunoglobulin G (IgG) antibody-binding domain of protein G (protein GB1) was studied to demonstrate how we can preserve the protein native structure and control the protein orientation on graphene surface by redesigning protein mutants. Various experimental tools including sum frequency generation vibrational spectroscopy, attenuated total refection-Fourier transform infrared spectroscopy, fluorescence spectroscopy, and circular dichroism spectroscopy were used to study the protein GB1 structure on graphene, supplemented by molecular dynamics simulations. By carefully designing the protein GB1 mutant, we can avoid strong unfavorable interactions between protein and graphene to preserve protein conformation and to enable the protein to adopt a preferred orientation. The methodology developed in this study is general and can be applied to study different proteins on graphene and beyond. With the knowledge obtained from this research, one could apply this method to optimize protein function on surfaces (e.g., to enhance biosensor sensitivity).

Molecular Mechanisms of Interactions between Monolayered Transition Metal Dichalcogenides and Biological Molecules.

Single layered two-dimensional (2D) materials such as transition metal dichalcogenides (TMDs) show great potential in many microelectronic or nanoelectronic applications. For example, because of extremely high sensitivity, TMD-based biosensors have become promising candidates for next-generation label-free detection. However, very few studies have been conducted on understanding the fundamental interactions between TMDs and other molecules including biological molecules, making the rational design of TMD-based sensors (including biosensors) difficult. This study focuses on the investigations of the fundamental interactions between proteins and two widely researched single-layered TMDs, MoS2, and WS2 using a combined study with linear vibrational spectroscopy attenuated total reflectance FTIR and nonlinear vibrational spectroscopy sum frequency generation vibrational spectroscopy, supplemented by molecular dynamics simulations. It was concluded that a large surface hydrophobic region in a relatively flat location on the protein surface is required for the protein to adsorb onto a monolayered MoS2 or WS2 surface with preferred orientation. No disulfide bond formation between cysteine groups on the protein and MoS2 or WS2 was found. The conclusions are general and can be used as guiding principles to engineer proteins to attach to TMDs. The approach adopted here is also applicable to study interactions between other 2D materials and biomolecules.

An Onboard Vision-Based System for Autonomous Landing of a Low-Cost Quadrotor on a Novel Landing Pad.

In this paper, an onboard vision-based system for the autonomous landing of a low-cost quadrotor is presented. A novel landing pad with different optical markers sizes is carefully designed to be robustly recognized at different distances. To provide reliable pose information in a GPS (Global Positioning System)-denied environment, a vision algorithm for real-time landing pad recognition and pose estimation is implemented. The dynamic model of the quadrotor is established and a system scheme for autonomous landing control is presented. A series of autonomous flights have been successfully performed, and a video of the experiment is available online. The efficiency and accuracy of the presented vision-based system is demonstrated by using its position and attitude estimates as control inputs for the autonomous landing of a self-customized quadrotor.

Chemically Immobilized Antimicrobial Peptide on Polymer and Self-Assembled Monolayer Substrates.

Surfaces with chemically immobilized antimicrobial peptides have been shown to have great potential in various applications such as biosensors and antimicrobial coatings. This research investigated the chemical immobilization of a cecropin-melittin hybrid antimicrobial peptide on two different surfaces, a polymer surface prepared by chemical vapor deposition (CVD) polymerization and a self-assembled monolayer surface. We probed the structure of immobilized peptides using spectroscopic methods and correlated such structural information to the measured antimicrobial activity. We found that the hybrid peptide adopts an α-helical structure after immobilization onto both surfaces. As we have shown previously for another α-helical peptide, MSI-78, immobilized on a SAM, we found that the α-helical hybrid peptide lies down when it contacts bacteria. This study shows that the antimicrobial activity of the surface-immobilized peptides on the two substrates can be well explained by the spectroscopically measured peptide structural data. In addition, it was found that the polymer-based antimicrobial peptide coating is more stable. This is likely due to the fact that the SAM prepared using silane may be degraded after several days whereas the polymer prepared by CVD polymerization is more stable than the SAM, leading to a more stable antimicrobial coating.

Association of single nucleotide polymorphisms of IL23R and IL17 with necrotizing enterocolitis in premature infants.

Necrotizing enterocolitis (NEC) is a severe gastrointestinal inflammatory disease in neonates, particularly in preterm infants. The interleukin (IL) 23/IL17 axis has been shown to play an important role in the gastrointestinal inflammation. However, the association of gene polymorphisms in the IL23/IL17 axis and the development of NEC remains unknown. In this study, we aimed to explore a possible genetic role of IL23R and IL17 in the development of NEC. We identified single nucleotide polymorphisms (SNPs) in IL23R (rs10889677), IL17A (rs2275913), and IL17F (rs763780) by polymerase chain reaction and Sanger sequencing. A total of 102 NEC patients (stage II, n = 75; and stage III, n = 27) and 120 control subjects were recruited for the study. All of the participants were premature (gestational age < 37 weeks). Our results revealed that the combination of the IL17F rs763780 (TC + CC) genotype and the C allele both significantly increased the risk of NEC [odds ratio (OR) 1.89, 95% confidence interval (CI) 1.04-3.43, P = 0.035; OR 1.82, 95% CI 1.06-3.13, P = 0.028, respectively]. Furthermore, the rs763780 (TC + CC) genotype was associated with increased severity of NEC and the incidence of NEC-related perforation [OR 2.80, 95% CI 1.10-7.12, P = 0.031; OR 3.86, 95% CI 1.10-13.53, P = 0.035, respectively]. However, IL23R rs10889677 and IL17A rs2275913 were not associated with the susceptibility to NEC. In conclusion, our data suggest that a variant of IL17F (rs763780) may contribute to the development of NEC.

Influence of Varied Environment Conditions on the Gut Microbiota of Yaks.

Despite the crucial role of the gut microbiota in different physiological processes occurring in the animal body, reports regarding the gut microbiota of animals residing in different environmental conditions like high altitude and different climate settings are limited. The Qinghai-Tibetan Plateau is renowned for its extreme climatic conditions that provide an ideal environment for exploring the effects of high altitude and temperature on the microbiota of animals. Yaks have unique oxygen delivery systems and genes related to hypoxic response. Damxung, Nyêmo, and Linzhou counties in Tibet have variable altitudes and temperatures that offer distinct settings for studying yak adaptation to elevated terrains. The results of our study suggest that amplicon sequencing of V3-V4 and internal transcribed spacer 2 (ITS2) regions yielded 13,683 bacterial and 1912 fungal amplicon sequence variants (ASVs). Alpha and beta diversity indicated distinct microbial structures. Dominant bacterial phyla were Firmicutes, Bacteroidota, and Actinobacteriota. Genera UCG-005, Christensenellaceae_R-7_group, and Rikenellaceae_RC9_gut_group were dominant in confined yaks living in Damxung county (DXS) and yaks living in Linzhou county (LZS), whereas UCG-005 prevailed in confined yaks living in Nyêmo county (NMS). The linear discriminant analysis effect size (LEfSe) analysis highlighted genus-level differences. Meta-stat analysis revealed significant shifts in bacterial and fungal community composition in yaks at different high altitudes and temperatures. Bacterial taxonomic analysis revealed that two phyla and 32 genera differed significantly (p < 0.05). Fungal taxonomic analysis revealed that three phyla and four genera differed significantly (p < 0.05). Functional predictions indicated altered metabolic functions, especially in the digestive system of yaks living in NMS. This study reveals significant shifts in yak gut microbiota in response to varying environmental factors, such as altitude and temperature, shedding light on previously unexplored aspects of yak physiology in extreme environments.

Intervention model under the Omaha system framework can effectively improve the sleep quality and negative emotion of patients with mid to late-stage lung cancer and is a protective factor for quality of life.

This study aims to evaluate the effects of Omaha System framework interventions on quality of life, emotional well-being, and sleep quality in 507 mid to late-stage lung cancer patients. Retrospectively, we compared data of 294 patients receiving conventional care (conventional group) with 213 patients undergoing Omaha System interventions (intervention group) from January 2019 to January 2023. Key indicators included quality of life (FACT-L), anxiety (SAS), depression (SDS), sleep quality (PSQI), hope (HHS), and dignity (PDI). Post-intervention, the intervention group showed a significant increase in FACT-L scores (P<0.001), indicating enhanced quality of life. There was a notable reduction in PSQI scores (P<0.001), suggesting improved sleep quality. Additionally, their anxiety and depression levels significantly decreased, as evidenced by lower SAS (P<0.001) and SDS scores (P<0.001). Logistic regression revealed that care nursing intervention scheme (P=0.007), age (P=0.008), marital status (P=0.002), per capita monthly household income (P=0.004), SAS after intervention (P=0.002), and PSQI after intervention (P=0.002) had a positive influence on quality of life. In conclusion, the Omaha System interventions markedly improved the quality of life, emotional state, and sleep in lung cancer patients.

[Establishment and Evaluation Strategy of an in vitro Cell Model of Bone Marrow Microenvironment Injury in Mouse Acute Graft-Versus-Host Disease].

OBJECTIVE: To establish a mesenchymal stem cell（MSC）-based in vitro cell model for the evaluation of mouse bone marrow acute graft-versus-host disease (aGVHD). METHODS: Female C57BL/6N mice aged 6-8 weeks were used as bone marrow and lymphocyte donors, and female BALB/c mice aged 6-8 weeks were used as aGVHD recipients. The recipient mouse received a lethal dose (8.0 Gy,72.76 cGy/min) of total body γ irradiation, and injected with donor mouse derived bone marrow cells (1×107/mouse) in 6-8 hours post irradiation to establish a bone marrow transplantation (BMT) mouse model (n=20). In addition, the recipient mice received a lethal dose (8.0 Gy,72.76 cGy/min) of total body γ irradiation, and injected with donor mouse derived bone marrow cells (1×107/mouse) and spleen lymphocytes (2×106/mouse) in 6-8 hours post irradiation to establish a mouse aGVHD model (n=20). On the day 7 after modeling, the recipient mice were anesthetized and the blood was harvested post eyeball enucleation. The serum was collected by centrifugation. Mouse MSCs were isolated and cultured with the addition of 2%, 5%, and 10% recipient serum from BMT group or aGVHD group respectively. The colony-forming unit-fibroblast（CFU-F) experiment was performed to evaluate the potential effects of serums on the self-renewal ability of MSC. The expression of CD29 and CD105 of MSC was evaluated by immunofluorescence staining. In addition, the expression of self-renewal-related genes including Oct-4, Sox-2, and Nanog in MSC was detected by real-time fluorescence quantitative PCR（RT-qPCR). RESULTS: We successfully established an in vitro cell model that could mimic the bone marrow microenvironment damage of the mouse with aGVHD. CFU-F assay showed that, on day 7 after the culture, compared with the BMT group, MSC colony formation ability of aGVHD serum concentrations groups of 2% and 5% was significantly reduced （P < 0．05）; after the culture, at day 14, compared with the BMT group, MSC colony formation ability in different aGVHD serum concentration was significantly reduced （P < 0．05）. The immunofluorescence staining showed that, compared with the BMT group, the proportion of MSC surface molecules CD29+ and CD105+ cells was significantly dereased in the aGVHD serum concentration group (P < 0.05), the most significant difference was at a serum concentration of 10% （P < 0．001, P < 0.01）. The results of RT-qPCR detection showed that the expression of the MSC self-renewal-related genes Oct-4, Sox-2, and Nanog was decreased, the most significant difference was observed at an aGVHD serum concentration of 10% （P < 0.01,P < 0．001,P < 0．001）. CONCLUSION: By co-culturing different concentrations of mouse aGVHD serum and mouse MSC, we found that the addition of mouse aGVHD serum at different concentrations impaired the MSC self-renewal ability, which providing a new tool for the field of aGVHD bone marrow microenvironment damage.

Identification of sedative-hypnotic compounds shared by five medicinal Polyporales mushrooms using UPLC-Q-TOF-MS/MS-based untargeted metabolomics.

BACKGROUND: Five Polyporales mushrooms, namely Amauroderma rugosum, Ganoderma lucidum, G. resinaceum, G. sinense and Trametes versicolor, are commonly used in China for managing insomnia. However, their active components for this application are not fully understood, restricting their universal recognition. PURPOSE: In this study, we aimed to identify sedative-hypnotic compounds shared by these five Polyporales mushrooms. STUDY DESIGN AND METHODS: A UPLC-Q-TOF-MS/MS-based untargeted metabolomics, including OPLS-DA (orthogonal projection of potential structure discriminant analysis) and OPLS (orthogonal projections to latent structures) analysis together with mouse assays, were used to identify the main sedative-hypnotic compounds shared by the five Polyporales mushrooms. A pentobarbital sodium-induced sleeping model was used to investigate the sedative-hypnotic effects of the five mushrooms and their sedative-hypnotic compounds. RESULTS: Ninety-two shared compounds in the five mushrooms were identified. Mouse assays showed that these mushrooms exerted sedative-hypnotic effects, with different potencies. Six triterpenes [four ganoderic acids (B, C1, F and H) and two ganoderenic acids (A and D)] were found to be the main sedative-hypnotic compounds shared by the five mushrooms. CONCLUSION: We for the first time found that these six triterpenes contribute to the sedative-hypnotic ability of the five mushrooms. Our novel findings provide pharmacological and chemical justifications for the use of the five medicinal mushrooms in managing insomnia.

Engineering Rieske oxygenase activity one piece at a time.

Enzyme engineering plays a central role in the development of biocatalysts for biotechnology, chemical and pharmaceutical manufacturing, and environmental remediation. Rational design of proteins has historically relied on targeting active site residues to confer a protein with desirable catalytic properties. However, additional "hotspots" are also known to exist beyond the active site. Structural elements such as subunit-subunit interactions, entrance tunnels, and flexible loops influence enzyme catalysis and serve as potential "hotspots" for engineering. For the Rieske oxygenases, which use a Rieske cluster and mononuclear iron center to catalyze a challenging set of reactions, these outside of the active site regions are increasingly being shown to drive catalytic outcomes. Therefore, here, we highlight recent work on structurally characterized Rieske oxygenases that implicates architectural pieces inside and outside of the active site as key dictators of catalysis, and we suggest that these features may warrant attention in efforts aimed at Rieske oxygenase engineering.

A novel inducible haematopoietic cell-depleting mouse model for chimeric complementation of blood cells.

Haematopoietic stem cell transplantation (HSCT) is widely used in regenerative medicine. HSCT can be used not only to treat certain types of blood cancer and immune disorders but also to induce immune tolerance in organ transplantation. However, the inadequacy of HSCs available for transplantation is still a major hurdle for clinical applications. Here, we established a novel inducible haematopoietic cell-depleting mouse model and tested the feasibility of using chimeric complementation to regenerate HSCs and their progeny cells. Large populations of syngeneic and major histocompatibility-mismatched haematopoietic cells were successfully regenerated by this model. The stable allogeneic chimeric mice maintained a substantial population of donor HSCs and Tregs, which indicated that the donor allogeneic HSCs successfully repopulated the recipient blood system, and the regenerated donor Tregs played essential roles in establishing immune tolerance in the allogeneic recipients. In addition, rat blood cells were detected in this model after xenotransplantation of rat whole bone marrow (BM) or Lin- BM cells. This mouse model holds promise for regenerating xenogeneic blood cells, including human haematopoietic cells.

Custom tuning of Rieske oxygenase reactivity.

Rieske oxygenases use a Rieske-type [2Fe-2S] cluster and a mononuclear iron center to initiate a range of chemical transformations. However, few details exist regarding how this catalytic scaffold can be predictively tuned to catalyze divergent reactions. Therefore, in this work, using a combination of structural analyses, as well as substrate and rational protein-based engineering campaigns, we elucidate the architectural trends that govern catalytic outcome in the Rieske monooxygenase TsaM. We identify structural features that permit a substrate to be functionalized by TsaM and pinpoint active-site residues that can be targeted to manipulate reactivity. Exploiting these findings allowed for custom tuning of TsaM reactivity: substrates are identified that support divergent TsaM-catalyzed reactions and variants are created that exclusively catalyze dioxygenation or sequential monooxygenation chemistry. Importantly, we further leverage these trends to tune the reactivity of additional monooxygenase and dioxygenase enzymes, and thereby provide strategies to custom tune Rieske oxygenase reaction outcomes.

Lin- PU.1dim GATA-1- defines haematopoietic stem cells with long-term multilineage reconstitution activity.

Despite extensive characterization of the state and function of haematopoietic stem cells (HSCs), the use of transcription factors to define the HSC population is still limited. We show here that the HSC population in mouse bone marrow can be defined by the distinct expression levels of Spi1 and Gata1. By using a double fluorescence knock-in mouse model, PGdKI, in which the expression levels of PU.1 and GATA-1 are indicated by the expression of GFP and mCherry, respectively, we uncover that the HSCs with lymphoid and myeloid repopulating activity are specifically enriched in a Lin- PU.1dim GATA-1- (LPG) cell subset. In vivo competitive repopulation assays demonstrate that bone marrow cells gated by LPG exhibit haematopoietic reconstitution activity which is comparable to that of classical Lin- Sca1+ c-kit+ (LSK). The integrated analysis of single-cell RNA sequence data from LPG and LSK-gated cells reveals that a transcriptional network governed by core TFs contributes to regulation of HSC multipotency. These discoveries provide new clues for HSC characterization and functional study.

[Establishment and Evaluation of Intestinal Injury Model of Mouse Acute Graft Versus Host Disease Based on An Organoid Technology].

OBJECTIVE: To establish an intestinal organoid model that mimic acute graft versus host disease (aGVHD) caused intestinal injuries by using aGVHD murine model serum and organoid culture system, and explore the changes of aGVHD intestine in vitro by advantage of organoid technology. METHODS: 20-22 g female C57BL/6 mice and 20-22 g female BALB/c mice were used as donors and recipients for bone marrow transplantation, respectively. Within 4-6 h after receiving a lethal dose (8.0 Gy) of γ ray total body irradiation, a total of 0.25 ml of murine derived bone marrow cells (1×107/mice, n=20) and spleen nucleated cells (5×106/mice, n=20) was infused to establish a mouse model of aGVHD (n=20). The aGVHD mice were anesthetized at the 7th day after transplantation, and the veinal blood was harvested by removing the eyeballs, and the serum was collected by centrifugation. The small intestinal crypts of healthy C57BL/6 mice were harvested and cultivated in 3D culture system that maintaining the growth and proliferation of intestinal stem cells in vitro. In our experiment, 5%, 10%, 20% proportions of aGVHD serum were respectively added into the organoid culture system for 3 days. The formation of small intestinal organoids were observed under an inverted microscope and the morphological characteristics of intestinal organoids in each groups were analyzed. For further evaluation, the aGVHD intestinal organoids were harvested and their pathological changes were observed. Combined with HE staining, intestinal organ morphology evaluation was performed. Combined with Alcian Blue staining, the secretion function of aGVHD intestinal organoids was observed. The distribution and changes of Lgr5+ and Clu+ intestinal stem cells in intestinal organoids were analyzed under the conditions of 5%, 10% and 20% serum concentrations by immunohistochemical stainings. RESULTS: The results of HE staining showed that the integrity of intestinal organoids in the 5% concentration serum group was better than that in the 10% and 20% groups. The 5% concentration serum group showed the highest number of organoids, the highest germination rate and the lowest pathological score among experimental groups, while the 20% group exhibited severe morphological destruction and almost no germination was observed, and the pathological score was the highest among all groups(t=3.668, 4.334,5.309,P<0.05). The results of Alican blue staining showed that the secretion function of intestinal organoids in serum culture of aGVHD in the 20% group was weaker than that of the 5% group and 10% of the organoids, and there was almost no goblet cells, and mucus was stainned in the 20% aGVHD serum group. The immunohistochemical results showed that the number of Lgr5+ cells of intestinal organoids in the 5% group was more than that of the intestinal organoids in the 10% aGVHD serum group and 20% aGVHD serum group. Almost no Clu+ cells were observed in the 5% group. The Lgr5+ cells in the 20% group were seriously injuried and can not be observed. The proportion of Clu+ cells in the 20% group significantly increased. CONCLUSION: The concentration of aGVHD serum in the culture system can affect the number and secretion function of intestinal organoids as well as the number of intestinal stem cells in organoids. The higher the serum concentration, the greater the risk of organoid injury, which reveal the characteristics of the formation and functional change of aGVHD intestinal organoids, and provide a novel tool for the study of intestinal injury in aGVHD.

Research on the Application of MEMS Intelligent Sensor in Abnormal Monitoring of Metro Tunnel by Simplified Model Tests.

The current monitoring methods for tunnel structure deformation mainly focus on laser distance measurement, fiber Bragg grating, photogrammetry, electronic total station, hydrostatic leveling and so on. Compared with traditional monitoring methods, MEMS sensors have the advantages of small size, low cost, low energy consumption and high accuracy. In this paper, MEMS sensors are used for the continuous real-time intelligent monitoring of model tunnels, and the multi-point deployment of MEMS sensors is set up for the tunnel structure monitoring with the indicators of acceleration and inclination. The results demonstrated that ß-sample interpolation of the angles of the MEMS measurement points, and then integration of the overall displacements can better reflect the form of uneven settlement of the tunnel. For tunnel models with uneven settlement as the main deformation, the angle interpolation method allows the MEMS sensor to measure the vertical displacement more accurately and to determine the load mode to a certain extent. However, for tunnel models with global settlement as the main deformation, the results vary considerably from reality, as only the uneven part of the settlement can be measured using the angular interpolation method.