Attitude measurement of ultraclose-range spacecraft based on improved YOLOv5s and adaptive Hough circle extraction.

In order to fulfill the requirements for various operations in space, such as rendezvous, docking, and capturing, there is a pressing need to achieve ultraclose-range spacecraft pose measurement. This paper addresses the challenges of pose measurement under low-light conditions at ultraclose range by introducing a stereovision solution based on target detection and adaptive circle extraction. Initially, an improved target detection algorithm is employed to expedite feature object detection. Subsequently, an adaptive circle extraction algorithm is developed through analysis of camera imaging to surmount challenges related to feature extraction and potential feature loss in the space environment. This approach facilitates swift and accurate measurement of spacecraft at ultraclose range. The results showcase a 66.36% reduction in parameter count for the enhanced target detection algorithm compared with the prevalent YOLOv7_tiny algorithm. Additionally, the adaptive circle extraction algorithm demonstrates an 11.4% increase in cooperative target feature extraction precision compared with existing methods while maintaining requisite detection speed. Simulation experiments indicate that the real-time position measurement error for spacecraft at ultraclose range is less than 0.18 mm, and angle measurement error is less than 0.05°. This presents a viable visual solution for spacecraft pose measurement at ultraclose range in low-light environments.

DHX33 mediates p53 to regulate mevalonate pathway gene transcription in human cancers.

Tumor suppressor p53 is frequently null or mutated in human cancers. Here in this study, DHX33 protein was found to be induced in p53 null cells in vitro, and in p53 mutant lung tumorigenesis in vivo. Cholesterol metabolism through mevalonate pathway is pivotal for cell proliferation and is frequently altered in human cancers. Mice carrying mutant p53 and KrasG12D alleles showed upregulation of mevalonate pathway gene expression. However upon DHX33 loss, their upregulation was significantly debilitated. Additionally, in many human cancer cells, DHX33 knockdown caused inhibition of mavelonate pathway gene transcription. We propose DHX33 locates downstream of mutant p53 and Ras to regulate mevalonate pathway gene transcription and thereby supports cancer development in vivo.

Integrating bioinformatics and experimental models to investigate the mechanism of the chelidonine-induced mitotic catastrophe via the AKT/FOXO3/FOXM1 axis in breast cancer cells.

Breast cancer (BC) is currently the most frequent and lethal cancer among women, and therefore, identification of novel biomarkers and potential anticancer agents for BC is crucial. Chelidonine is one of the main active ingredients of Chelidonium majus, which has been applied in Chinese medicine prescriptions to treat cancer. This paper aimed to evaluate the ability of chelidonine to trigger mitotic catastrophe in BC cells and to clarify its mechanism through the AKT/FOXO3/FOXM1 pathway. Bioinformatics analysis revealed that forkhead box O3 (FOXO3) was downregulated in different subtypes of BC. Factors such as age, stage, Scarff-Bloom-Richardson (SBR) grade, diverse BC subclasses, and triple-negative status were inversely correlated to FOXO3 levels in BC patients compared with healthy controls. Notably, patients exhibiting higher FOXO3 expression levels demonstrated better overall survival (OS) and relapse-free survival (RFS). Moreover, FOXM1 levels were negatively correlated with both OS and RFS in BC patients. These results revealed that FOXO3 might be considered a predictive biomarker for the prognosis of BC. By utilizing Gene Set Enrichment Analysis (GSEA), we delved into the main Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment pathways of FOXO3, and the results suggested that FOXO3 was mainly involved in cancer-related pathways and the cell cycle. Thereafter, MTT and flow cytometry (FCM) analysis indicated that chelidonine inhibited BC cell line proliferation and induced M phase arrest. It was found that chelidonine treatment induced MCF-7 cell apoptosis, significantly reduced the expression of survivin and promoted the expression of p53 and caspase-9. Further morphological observation illustrated depolymerization of the actin skeleton and shortening of actin filaments in BC cells, leading to the typical characteristics of mitotic catastrophe, such as abnormal mitosis and multinucleated cells. Western blot analysis demonstrated that chelidonine inhibited the expression of p-AKT to promote the expression of FOXO3 protein and weaken the expression levels of FOXM1 and polo-like kinase 1 (PLK1). Taken together, our present work proved that FOXO3 might be considered a potential therapeutic target for BC. Chelidonine emerges as a promising agent to treat BC by inducing M phase arrest of BC cells and hindering the AKT/FOXO3/FOXM1 axis, thereby inducing mitotic catastrophe in BC.

Improvement of the fibrinolytic activity, acid resistance and thermostability of nattokinase by surface charge engineering.

Nattokinase is a promising thrombolytic drug due to its powerful fibrinolytic effect and few side effects. However, the low fibrinolytic activity and stability of nattokinase have limited its industrial production and oral application. In this study, the basic and neutral amino acid residues on the surface of recombinant nattokinase AprY from Bacillus mojavensis LY-06 (rAprY) were mutated to acidic amino acid residues by surface charge engineering strategy, and two variants K12D and N109D with 92.6 % and 8.4 % increased fibrinolytic activity were obtained. The R45E variant with enhanced acid stability and thermostability was also screened, its acid stability at pH 4 and t1/2 at 55 °C were 3.7-fold and 1.8-fold higher than that of wild type rAprY, respectively. Bioinformatics analysis showed that the increased activities of K12D and N109D variants were related to the increased flexibility of the region around their active centers. The increased rigidity of 97-103 amino acid residues around the active center of R45E may be the reason for its enhanced stability and reduced catalytic activity. The multipoint mutation K12D-N109D (M2)'s catalytic activity did not increase cumulatively, but its pH stability did. The nattokinase variants generated in this study have potential for industrial production and application.

Combined Computer-Aided Predictors to Improve the Thermostability of Nattokinase.

Food-derived nattokinase has strong thrombolytic activity and few side effects. In the field of medicine, nattokinase has been developed as an adjuvant drug for the treatment of thrombosis, and nattokinase-rich beverages and health foods have also shown great potential in the field of food development. At present, the poor thermostability of nattokinase limits its industrial production and application. In this study, we used several thermostability-prediction algorithms to predict nattokinase from Bacillus mojavensis LY-06 (AprY), and screened two variants S33T and T174V with increased thermostability and fibrinolytic activity. The t1/2 of S33T and T174V were 8.87-fold and 2.51-fold those of the wild type AprY, respectively, and their enzyme activities were also increased (1.17-fold and 1.28-fold, respectively). Although the thermostability of N218L was increased by 2.7 times, the fibrinolytic activity of N218L was only 73.3% of that of wild type AprY. The multiple-point mutation results showed that S33T-N218L and S33T-T174V-N218L variants lost their activity, and the T174V-N218L variant did not show any significant change in catalytic performance, while S33T-T174V increased its thermostability and activity by 21.3% and 24.8%, respectively. Although the S33T-T174V variant did not show the additive effect of thermostability, it combined the excellent transient thermostability of S33T with the better thrombolytic activity of T174V. Bioinformatics analysis showed that the overall structure of S33T and T174V variants tended to be stable, while the structure of S33T-T174V variant was more flexible. Local structure analysis showed that the increased rigidity of the active center region (positions 64-75) and the key loop region (positions 129-130, 155-163, 187-192, 237-241, and 268-270) determined the increased thermostability of all variants. In addition, the enhanced flexibility of S33T-T174V variant in the Ca1 binding region (positions 1-4, 75-82) and the peripheral region of the catalytic pocket (positions 210-216) may account for the inability to superpose its thermostability. We explored the effective strategy to enhance the thermostability of nattokinase, and the resulting variants have potential industrial production and application.

Characterization of a Nattokinase from the Newly Isolated Bile Salt-Resistant Bacillus mojavensis LY-06.

Nattokinase is a potential new thrombolytic drug because of its strong thrombolytic effect, high safety, and low cost. However, there is no research reporting on bile salt-tolerant nattokinase-producing probiotics. In this study, the bile salt-tolerant nattokinase-producing strain Bacillus mojavensis LY-06 was isolated from local Xinjiang douchi, and the fermentation yield of nattokinase of 1434.64 U/mL was obtained by both a single factor experiment and an orthogonal experiment. A gene responsible for fibrinolysis (aprY) was cloned from the genome of strain Bacillus mojavensis LY-06, and the soluble expression of this gene in Escherichia coli (rAprY, fused with His-tag at C-terminus) was achieved; molecular docking elucidates the cause of insoluble expression of rAprY. The optimal pH and temperature for the fibrinolysis activity of nattokinase AprY fermented by Bacillus mojavensis LY-06 were determined to be pH 6.0 and 50 °C, respectively. However, the optimal pH of rAprY expressed in Escherichia coli was 8, and its acid stability, thermal stability, and fibrinolytic activity were lower than those of AprY. Bioinformatics analysis found that the His-tag carried at the C-terminus of rAprY could affect its acidic stability by changing the isoelectric point and surface charge of the enzyme; in contrast to AprY, changes in the number of internal hydrogen bonds and the flexibility of the loop region in the structure of rAprY resulted in lower fibrinolytic activity and poorer thermal stability.

[Mechanism of Bupleurum scorzonerifolium and Paeonia lactiflora herbal pair against liver cancer: an exploration based on UPLC-Q-TOF-MS combined with network pharmacology].

This study aimed to decipher the pharmacodynamic material basis and mechanism of herbal pair Bupleurum scorzonerifolium-Paeonia lactiflora(BS-PL) against liver cancer based on UPLC-Q-TOF-MS and network pharmacology. MTT assay and human hepatocellular carcinoma HepG2 cells were used to screen the effective part of BS-PL, the active components of which were further analyzed and identified by UPLC-Q-TOF-MS. Next, we applied Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP) to screen the active ingredients with OB≥30%. Then TCMSP and SwissTargetPrediction were used to collect and predict component targets, followed by the search of liver cancer-related targets with GeneCards and DisGeNET. The intersection targets were obtained using Venny 2.1.0. Protein-protein interaction(PPI) network was constructed using STRING to uncover the core targets, which were subjected to Gene Ontology(GO) and Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment analysis based on DAVID. Finally, the effects of active ingredients on the expression of main proteins enriched in the key pathways of HepG2 cells were verified by Western blot. The results indicated that compared with 30%, 50%, and 70% ethanol extracts of BS-PL, the n-butanol extraction part(CSYZ) from 95% ethanol extract of BS-PL exhibited the best anti-tumor effect. UPLC-Q-TOF-MS revealed 31 ingredients, 14 of which showed OB≥30%. A total of 220 intersection targets were obtained, from which 35 were selected as the key targets under the condition of two times the median of degree. Among the 215 items with P<0.05 obtained through GO enrichment analysis, 154 were classified into biological processes, 22 into cell components and 39 into molecular functions. KEGG enrichment analysis revealed 95 significantly affected signaling pathways, and the ones(sorted in a descending order by P value) closely related to the anti-liver cancer effect of herbal pair were PI3 K-AKT signaling pathway, TNF signaling pathway, MAPK signaling pathway, HIF-1 signaling pathway, and ErbB signaling pathway. Finally, the PI3 K/AKT signaling pathway involving the largest number of targets was extrapolated, and it was found that this pathway contained 15 core targets and 8 active components. Experimental verification showed that the effective components of BS-PL significantly inhibited the expression of p-PI3 K and p-AKT, consistent with the prediction results of network pharmacology. In conclusion, the main pharmacodynamic substances of BS-PL against liver cancer are 14 components like saikosaponin a, saikosaponin d, and paeoniflorin, which exert the anti-liver cancer effect by regulating PI3 K/AKT pathway.

Targeting the PDGF/PDGFR signaling pathway for cancer therapy: A review.

Platelet-derived growth factors (PDGFs) and PDGF receptors (PDGFRs) are expressed in a variety of tumors. Activation of the PDGF/PDGFR signaling pathway is associated with cancer proliferation, metastasis, invasion, and angiogenesis through modulating multiple downstream pathways, including phosphatidylinositol 3 kinase/protein kinase B pathway and mitogen-activated protein kinase/extracellular signal-regulated kinase pathway. Therefore, targeting PDGF/PDGFR signaling pathway has been demonstrated to be an effective strategy for cancer therapy, and accordingly, some great progress has been made in this field in the past few decades. This review will focus on the PDGF isoforms and their binding with the related PDGFRs, the PDGF/PDGFR signaling and regulation, and especially present strategies and inhibitors developed for cancer therapy, and the related clinical benefits and side effects.