Dickensmarshall4995
Alcohol acyltransferases (AATs) enables microbial biosynthesis of a large space of esters by condensing an alcohol and an acyl-CoA. However, substrate promiscuity of AATs prevents microbial biosynthesis of designer esters with high selectivity. Here, we developed a high-throughput microbial screening platform that facilitates rapid identification of AATs for designer ester biosynthesis. First, we established a microplate-based culturing technique with in situ fermentation and extraction of esters. We validated its capability in rapid profiling of the alcohol substrate specificity of 20 chloramphenicol acetyltransferase variants derived from Staphylococcus aureus (CATSa ) for microbial biosynthesis of acetate esters with various exogeneous alcohol supply. By coupling the microplate-based culturing technique with a previously established colorimetric assay, we developed a high-throughput microbial screening platform for AATs. We demonstrated that this platform could not only probe the alcohol substrate specificity of both native and engineered AATs but also identify the beneficial mutations in engineered AATs for enhanced ester synthesis. We anticipate the high-throughput microbial screening platform provides a useful tool to identify novel wildtype and engineered AATs that have important roles in nature and industrial biocatalysis for designer bioester production.Enzyme engineering toward catalytic-tetrad residues usually results in activity loss. Unexpectedly, we found that a directed evolution campaign yielded a beneficial residue A100 in KmCR (a carbonyl reductase from Kluyveromyces marxianus ZJB14056), which is a residue of catalytic tetrad and conserved according to multiple sequence alignment. Inspired by this finding, we performed saturation mutagenesis on all the four residues of catalytic tetrad of KmCR. A number of variants with improved enzymatic activities were obtained. Among them, the variant KmCR_A100S exhibited increased catalytic efficiency (kcat /KM = 47.3 s-1 ·mM-1 ), improved stereoselectivity (from moderate selectivity (deP = 66.7%) to strict (S)-selectivity (deP > 99.5%)), and extended substrate scope, compared to those of KmCR_WT. In silico analysis showed that a relay system was rebuilt in KmCR via the beneficial residue S100. Furthermore, comparison of 11 protein engineering campaigns indicated that the beneficial position is easily overlooked due to the long distance (>10 Å) from ketone substrates. Since CRs share similar catalytic mechanism, the knowledge gained from this study has universal significance to CR engineering.In this study, we show that maltose-binding protein (MBP) is capable of facilitating stable gold nanoparticle synthesis, and a structure of MBP in the presence of gold ions was determined by X-ray crystallography. Using this high-resolution structure of gold ion bound MBP, a peptide (AT1) was selected and synthesized and was shown to also aid in the synthesis of stable gold nanoparticles under similar experimental conditions to those used for protein facilitated synthesis. This structure-based approach represents a new potential method for the selection of peptides capable of facilitating stable nanoparticle synthesis.In the majority of cancers, pathogenic variants are only found at the level of the tumor; however, an unusual number of cancers and/or diagnoses at an early age in a single family may suggest a genetic predisposition. Predisposition plays a major role in about 5-10% of adult cancers and in certain childhood tumors. As access to genomic testing for cancer patients continues to expand, the identification of potential germline pathogenic variants (PGPVs) through tumor-DNA sequencing is also increasing. Statistical methods have been developed to infer the presence of a PGPV without the need of a matched normal sample. These methods are mainly used for exploratory research, for example in real-world clinico-genomic databases/platforms (CGDB). These databases are being developed to support many applications, such as targeted drug development, clinical trial optimization, and postmarketing studies. To ensure the integrity of data used for research, a quality management system should be established, and quality oversight activities should be conducted to assess and mitigate clinical quality risks (for patient safety and data integrity). As opposed to well-defined 'good practice' quality guidelines (GxP) areas such as good clinical practice, there are no comprehensive instructions on how to assess the clinical quality of statistically derived variables from sequencing data such as PGPVs. In this article, we aim to share our strategy and propose a possible set of tactics to assess the PGPV quality and to ensure data integrity in exploratory research.
Intestinal tumor is one of the most common tumors that seriously threaten the health of residents all over the world. Studies suggest that the imbalance of intestinal flora is associated with tumorgenesis; meanwhile, long-term regular aerobic exercise can improve the occurrence and development of tumors. However, moderate aerobic exercise affecting the development of intestinal tumors and their related flora has not been explored. Thus, the purpose of our study is to explore the effects of aerobic exercise on intestinal tumor growth and flora changes in Apc
mice, and try to answer whether there is a correlation between them after exercise intervention.
In this study, 18 required Apc
mice were randomly divided into Model group (n = 6), Exercise group (n = 6), and Aspirin group (positive control, n = 6), while C57BL/6J wild-type mice were used as the blank control group. Each group is given corresponding intervention. Weight monitoring, tumor counts, hematoxylin-eosin staining, TdT-mediated dUTP nick-enbundance and negative correlation with conditioned pathogens).
Changes in flora abundance may be one of the reasons for aerobic exercise to reduce the number of intestinal tumors, probably mediated by cell apoptosis. Future studies should focus on the potential mechanism of aerobic exercise in preventing intestinal tumorgenesis, especially the molecular mechanism through intestinal flora.
Aerobic exercise has a preventive effect on intestinal tumors in Apc
mice, and can regulate the abundance of intestinal flora.
Aerobic exercise has a preventive effect on intestinal tumors in ApcMin/+ mice, and can regulate the abundance of intestinal flora.
Obesity is associated with fatigue in many diseases, but the correlation between obesity and poststroke fatigue (PSF) is unclear. The study aimed to investigate the relationship between body mass index (BMI) and the occurrence of and recovery from PSF.
Within 3days of the onset of ischemic stroke, patients were consecutively recruited. We assessed PSF at admission and at 6, 12, and 24months with the Fatigue Severity Scale (FSS). Multivariable logistic regression and restricted cubic spline function were used to explore the relationships between baseline BMI and the risk of PSF at different time points. The correlation between baseline BMI and the dynamic changes in the natural logarithm transformation of the FSS (lnFSS) score during the follow-up period was analyzed by the piecewise linear mixed-effects model.
A total of 1026 stroke patients were included. Multivariable analyses indicated that obesity was associated with a decreased risk of early PSF (fatigue diagnosed at baseline) [odds ratio (OR) 0.61, 95% confidence interval (CI) 0.41-0.93] but an increased risk of late PSF (fatigue diagnosed 6months after the index stroke) (OR 1.63, 95% CI 1.06-2.50 for 6months; OR 1.87, 95% CI 1.18-2.96 for 12months; OR 2.11, 95% CI 1.28-3.49 for 24months). Longitudinal analyses indicated that in the late stage of fatigue, the higher the BMI category, the slower the rate of decrease was for the FSS score.
Obese patients are less likely to develop fatigue in the acute stage of ischemic stroke. However, they are more prone to late fatigue and exhibit a slower decline in the FSS score in the long term.
Obese patients are less likely to develop fatigue in the acute stage of ischemic stroke. However, they are more prone to late fatigue and exhibit a slower decline in the FSS score in the long term.Mercury (Hg) is a heavy metal widely distributed in ecological environment, poisoning the immune system of humans and animals. Selenium (Se) is an essential microelement and selenoproteins involved in the procedure of Se antagonizing organ toxicity induced by heavy metals. The aim of this research was to investigate the changes of gene expression profile of selenoproteins induced by mercuric chloride (HgCl2) in chicken spleen lymphocytes. We established cytotoxicity model of chicken spleen lymphocytes by HgCl2 exposure, the messenger RNA (mRNA) expression levels of 25 selenoproteins in spleen lymphocytes were analyzed by real-time quantitative PCR (qPCR), and the gene expression pattern of selenoproteins was revealed by principal component analysis (PCA). The results showed that the mRNA expression levels of 13 selenoproteins (GPX3, GPX4, TXNRD2, TXNRD3, DIO2, SELENOS, SELENON, SELENOT, SELENOO, SELENOP, SELENOP2, MSRB1, and SEPHS2) were decreased in HgCl2 treatment group, and there was strong positive correlation between these selenoproteins and component 1 as well as component 2 of the PCA. At the same time, the protein expression levels of GPX4, TXNRD1, TXNRD2, SELENOM, SELENOS, and SELENON were detected by Western blotting, which were consistent with the changes of gene expression. MF-438 order The results showed that the expression levels of selenoproteins were aberrant in response to HgCl2 toxicity. The information presented in this study provided clues for further research on the interaction between HgCl2 and selenoproteins, and the possible mechanism of immune organ toxicity induced by HgCl2.Positron emission tomography (PET) imaging using the amino acid tracer O-[2-(18F)fluoroethyl]-L-tyrosine (FET) has gained increased popularity within the past decade in the management of glioblastoma (GBM). Radiomics features extracted from FET PET images may be sensitive to variations when imaging at multiple time points. It is therefore necessary to assess feature robustness to test-retest imaging. Eight patients with histologically confirmed GBM that had undergone post-surgical test-retest FET PET imaging were recruited. In total, 1578 radiomic features were extracted from biological tumour volumes (BTVs) delineated using a semi-automatic contouring method. Feature repeatability was assessed using the intraclass correlation coefficient (ICC). The effect of both bin width and filter choice on feature repeatability was also investigated. 59/106 (55.7%) features from the original image and 843/1472 (57.3%) features from filtered images had an ICC ≥ 0.85. Shape and first order features were most stable. Choice of bin width showed minimal impact on features defined as stable. The Laplacian of Gaussian (LoG, σ = 5 mm) and Wavelet filters (HLL and LHL) significantly improved feature repeatability (p ≪ 0.0001, p = 0.003, p = 0.002, respectively). Correlation of textural features with tumour volume was reported for transparency. FET PET radiomic features extracted from post-surgical images of GBM patients that are robust to test-retest imaging were identified. An investigation with a larger dataset is warranted to validate the findings in this study.