ABSTRACT
Both alcohol-associated liver disease (ALD) and metabolic dysfunction-associated steatotic liver disease are leading contributors to chronic liver diseases. These conditions often coexist, exacerbating disease progression. Despite ALD being a leading cause of liver transplantation, many individuals with alcohol use disorder (AUD) do not receive treatment. In this review, we discussed the epidemiology of ALD in AUD, various treatment options for AUD, and their efficacy on liver health. Our critical analysis of current evidence underscores the need for integrated models involving multiple stakeholders to improve ALD management.
ABSTRACT
Alginate is one of the most important marine colloidal polysaccharides, and its oligosaccharides have been proven to possess diverse biological functions. Alginate lyases could specifically degrade alginate and therefore serve as desirable tools for the research and development of alginate. In this report, a novel catalytic domain, which demonstrated no significant sequence similarity with all previously defined functional domains, was verified to exhibit a random endo-acting lyase activity to alginate. The action pattern analysis revealed that the heterologously expressed protein, named Aly44A, preferred to degrade polyM. Its minimum substrates and the minimum products were identified as unsaturated alginate trisaccharides and disaccharides, respectively. Based on the sequence novelty of Aly44A and its homologs, a new polysaccharide lyase family (PL44) was proposed. The discovery of the novel enzyme and polysaccharide lyase family provided a new entrance for the gene-mining and acquiring of alginate lyases, and would facilitate to the utilization of alginate and its oligosaccharides.
Subject(s)
Alginates , Polysaccharide-Lyases , Polysaccharide-Lyases/metabolism , Polysaccharide-Lyases/chemistry , Polysaccharide-Lyases/genetics , Alginates/chemistry , Alginates/metabolism , Substrate Specificity , Catalytic Domain , Oligosaccharides/chemistry , Oligosaccharides/metabolism , Amino Acid Sequence , Hexuronic Acids/chemistry , Hexuronic Acids/metabolismABSTRACT
Soil quality is defined as the ability of soil to maintain the soil environment and the biosphere. Due to the limitation of salt and alkali stress, soil quality can be reduced, which in turn affects agricultural production. Biochar is widely used in saline-alkali land improvement because of its special pore structure and strong ion exchange ability, while Piriformospora indica is widely used in saline-alkali land improvement because it can symbiose with plants and improve plant stress resistance. However, the synergistic effect of combined biochar application and inoculation of P. indica on the quality of saline-alkali soil and plant development is uncertain. Hence, we investigated the combined influences of biochar and P. indica on the soil physicochemical characteristics, as well as the growth and chlorophyll florescence of sorghum-sudangrass hybrids (Sorghum bicolor × Sorghum sudane) in our study. The results indicated that after applying biochar and P. indica together, there was a considerable drop in soil pH, conductivity, Na+, and Cl- concentrations. Meanwhile, the soil organic matter (SOM), available phosphorus (AP), and alkaline hydrolyzable nitrogen (AN) increased by 151.81%, 50.84%, and 103.50%, respectively, when the Bamboo biochar was combined with 120 ml/pot of P. indica. Eventually, sorghum-sudangrass hybrid biomass, transpiration rate, and chlorophyll content increased by 111.69%, 204.98%, and 118.54%, respectively. According to our findings, using P. indica and biochar together can enhance soil quality and plant growth. The results also provide insights to enhance the quality of saline-alkali soils and the role of microorganisms in nutrient cycling.
ABSTRACT
A novel alginate lyase Aly7Aq was cloned and heterologous expressed by a combination of bioinformatics and molecular biology. Aly7Aq was an M-specific alginate lyase, exhibiting optimum reaction conditions at 50 °C and pH 10.0. Aly7Aq was determined to degrade polysaccharides in a random endo-acting manner. The minimum reaction substrate was tetrasaccharide, and Aly7Aq mainly attacked the third glycosidic linkage from the reducing end of oligosaccharide substrates. The disaccharide product of Aly7Aq was ΔM and the trisaccharide products were ΔMM and ΔMG, which differed from all previously characterized M-specific alginate lyases. The degradation products demonstrated that the ±2 subsites of Aly7Aq strictly recognized M units, while the -1 subsite accommodated both M and G units. Therefore, the substrate specificity of Aly7Aq was derived from the specificity of ±2 subsites. This is the first report on the specificity at subsite ±2 of M-specific alginate lyase. The novel M-specific Aly7Aq could serve as a potential tool in the specific degradation of alginate and targeted preparation of oligosaccharide.
Subject(s)
Alginates , Polysaccharide-Lyases , Polysaccharide-Lyases/chemistry , Polysaccharide-Lyases/metabolism , Polysaccharide-Lyases/genetics , Substrate Specificity , Alginates/chemistry , Oligosaccharides/chemistry , Oligosaccharides/metabolism , Cloning, Molecular , Hydrogen-Ion Concentration , Amino Acid SequenceABSTRACT
BACKGROUND: α-l-Fucose confers unique functions for fucose-containing biomolecules such as human milk oligosaccharides. α-l-Fucosidases can serve as desirable tools in the application of fucosylated saccharides. Discovering novel α-l-fucosidases and elucidating their enzyme properties are always worthy tasks. RESULTS: A GH95 family α-l-fucosidase named Afc95A_Wf was cloned from the genome of the marine bacterium Wenyingzhuangia fucanilytica and expressed in Escherichia coli. It exhibited maximum activity at 40 °C and pH 7.5. Afc95A_Wf defined a different substrate specificity among reported α-l-fucosidases, which was capable of hydrolyzing α-fucoside in CNP-fucose, Fucα1-2Galß1-4Glc and Galß1-4(Fucα1-3)Glc, and showed a preference for α1,2-fucosidic linkage. It adopted Asp residue in the amino acid sequence at position 391, which was distinct from the previously acknowledged residue of Asn. The predicted tertiary structure and site-directed mutagenesis revealed that Asp391 participates in the catalysis of Afc95A_Wf. The differences in the substrate specificity and catalytic site shed light on that Afc95A_Wf adopted a novel mechanism in catalysis. CONCLUSION: A GH95 family α-l-fucosidase (Afc95A_Wf) was cloned and expressed. It showed a cleavage preference for α1,2-fucosidic linkage to α1,3-fucosidic linkage. Afc95A_Wf demonstrated a different substrate specificity and a residue at an important catalytic site compared with known GH95 family proteins, which revealed the occurrence of diversity on catalytic mechanisms in the GH95 family. © 2024 Society of Chemical Industry.
ABSTRACT
Cultural ecosystem services (CES) provided by urban parks are crucial for encouraging residents to engage with nature and enhance their physical and mental well-being. Measuring these services from the residents' perception perspective is essential. Previous studies often focus on a specific type of CES, lacking explicit links between the landscape composition and configuration of urban parks and residents' perceptions of various CES. The main objective of this study, therefore, was to explore the effects of urban park landscape patterns on residents' CES perceptions. We took 12 urban parks in Chengdu, China, and assessed residents' CES perceptions through content analysis of social media texts. Spatial patterns of the parks were analyzed using remote sensing interpretation and field surveys. Correlation analysis examined the relationship between landscape patterns and residents' perceptions, with further verification through questionnaires and face-to-face interviews. Findings revealed that at the landscape level, landscape aggregation of parks was negatively correlated with aesthetic perceptions but positively correlated with recreational perceptions. Landscape diversity negatively impacted perceptions of sports and health (S&H). At the class level, natural elements significantly influenced residents' perceptions of aesthetic and S&H. Specifically, aesthetic perceptions were minimized when the landscape shape index of water bodies reached 6.36 or when the proportion of green space was 56.5 %. Road edge density negatively affected perceptions of S&H and influenced the distribution of water bodies and green spaces. These findings are crucial for optimizing park structures to deliver efficient CES and provide strategies for integrating ecosystem services into environmental management from a public perception perspective.
Subject(s)
Ecosystem , Parks, Recreational , China , Humans , Recreation , Conservation of Natural Resources , Cities , PerceptionABSTRACT
The rapidly aging population is consuming more alcohol, leading to increased alcohol-associated acute pancreatitis (AAP) with high mortality. However, the mechanisms remain undefined, and currently there are no effective therapies available. This study aims to elucidate aging- and alcohol-associated spatial transcriptomic signature by establishing an aging AAP mouse model and applying Visium spatial transcriptomics for understanding of the mechanisms in the context of the pancreatic tissue. Upon alcohol diet feeding and caerulein treatment, aging mice (18 months) developed significantly more severe AAP with 5.0-fold increase of injury score and 2.4-fold increase of amylase compared to young mice (3 months). Via Visium spatial transcriptomics, eight distinct tissue clusters were revealed from aggregated transcriptomes of aging and young AAP mice: five acinar, two stromal, and one islet, which were then merged into three clusters: acinar, stromal, and islet for the comparative analysis. Compared to young AAP mice, > 1300 differentially expressed genes (DEGs) and approximately 3000 differentially regulated pathways were identified in aging AAP mice. The top five DEGs upregulated in aging AAP mice include Mmp8, Ppbp, Serpina3m, Cxcl13, and Hamp with heterogeneous distributions among the clusters. Taken together, this study demonstrates spatial heterogeneity of inflammatory processes in aging AAP mice, offering novel insights into the mechanisms and potential drivers for AAP development. KEY MESSAGES: Mechanisms regarding high mortality of AAP in aging remain undefined. An aging AAP mouse model was developed recapturing clinical exhibition in humans. Spatial transcriptomics identified contrasted DEGs in aging vs. young AAP mice. Top five DEGs were Mmp8, Ppbp, Serpina3m, Cxcl13, and Hamp in aging vs. young AAP mice. Our findings shed insights for identification of molecular drivers in aging AAP.
Subject(s)
Aging , Pancreatitis , Transcriptome , Animals , Aging/genetics , Mice , Pancreatitis/genetics , Pancreatitis/chemically induced , Pancreatitis/metabolism , Pancreatitis/pathology , Gene Expression Profiling , Disease Models, Animal , Male , Inflammation/genetics , Mice, Inbred C57BL , Ethanol/adverse effects , Pancreatitis, Alcoholic/genetics , Pancreatitis, Alcoholic/metabolism , Pancreatitis, Alcoholic/pathology , Acute Disease , Pancreas/metabolism , Pancreas/pathologyABSTRACT
OBJECTIVE: The pancreatic ductal adenocarcinoma (PDAC) microenvironment is primarily composed of cancer-associated fibroblasts (CAFs) and immune cells. Gremlin1 (Grem1) is a profibrogenic factor that promotes tumorigenesis in several cancers. However, the role of Grem1 in the PDAC microenvironment is not adequately defined. METHODS: We correlated Grem1 levels with activated stroma and immune cells in human PDAC using The Cancer Genome Atlas (TCGA) RNA-sequencing data and characterized the expression of Grem1 transcripts and isoforms in pancreatic cell lines and PDAC tissues. We assessed the role of Grem1 in the microenvironment by in vitro studies. RESULTS: Grem1 expression is associated with an activated stroma and increased M1 and M2 macrophages. Only full length Grem1 variant 1 and isoform 1 were detectable in human pancreatic cells, and remarkably high levels of Grem1 were observed in pancreatic fibroblasts (P < 0.05). Immunohistochemistry detected Grem1 protein in PDAC tumor cells and stromal cells, which correlated with infiltrating macrophages in PDAC tumors. Grem1 knockdown in CAFs suppressed transforming growth factor (TGF)-ß-induced extracellular matrix proteins (P < 0.05). Grem1 recombinant protein treatment in vitro increased M1 and M2 macrophages (P < 0.05). CONCLUSIONS: Grem1 acts as a profibrogenic factor in the PDAC microenvironment via modulation of fibroblasts and macrophages. Grem1 may have the potential to be developed as a therapeutic target for PDAC.
ABSTRACT
Chondroitinases play important roles in structural and functional studies of chondroitin sulfates. Carbohydrate-binding module (CBM) is generally considered as an accessory module in carbohydrate-active enzymes, which promotes the association of the appended enzyme with the substrate and potentiates the catalytic activity. However, the role of natural CBM in chondroitinases has not been investigated. Herein, a novel chondroitinase ChABC29So containing an unknown domain with a predicted ß-sandwich fold was discovered from Segatella oris. Recombinant ChABC29So showed enzyme activity towards chondroitin sulfates and hyaluronic acid and acted in a random endo-acting manner. The unknown domain exhibited a chondroitin sulfate-binding capacity and was identified as a CBM. Biochemical characterization of ChABC29So and the CBM-truncated enzyme revealed that the CBM enhances the catalytic activity, thermostability, and disaccharide proportion in the final enzymatic products of ChABC29So. These findings demonstrate the role of the natural CBM in a chondroitinase and will guide future modification of chondroitinases.
Subject(s)
Chondroitin ABC Lyase , Chondroitin Sulfates , Chondroitin ABC Lyase/chemistry , Chondroitin ABC Lyase/metabolism , Chondroitin ABC Lyase/genetics , Chondroitin Sulfates/chemistry , Chondroitin Sulfates/metabolism , Substrate Specificity , Enzyme Stability , Protein Binding , Amino Acid Sequence , Recombinant Proteins/chemistry , Recombinant Proteins/metabolism , Hyaluronic Acid/chemistry , Hyaluronic Acid/metabolismABSTRACT
Chondroitin sulfate (CS) is the predominant glycosaminoglycan within the human body and is widely applied in various industries. Carbohydrate-binding modules (CBMs) possessing the capacity for carbohydrate recognition are verified to be important tools for polysaccharide investigation. Only one CS-specific CBM, PhCBM100, has hitherto been characterized. In the present study, two CBM96 domains present in the same putative PL8_3 chondroitin AC lyase were discovered and recombinantly expressed. The results of microtiter plate assays and affinity gel electrophoresis assays showed that the two corresponding proteins, DmCBM96-1 and DmCBM96-2, bind specifically to CSs. The crystal structure of DmCBM96-1 was determined at a 2.20 Å resolution. It adopts a ß-sandwich fold comprising two antiparallel ß-sheets, showing structural similarities to TM6-N4, which is the founding member of the CBM96 family. Site mutagenesis analysis revealed that the residues of Arg27, Lys45, Tyr51, Arg53, and Arg157 are critical for CS binding. The characterization of the two CBM96 proteins demonstrates the diverse ligand specificity of the CBM96 family and provides promising tools for CS investigation.
Subject(s)
Chondroitin Sulfates , Protein Binding , Chondroitin Sulfates/chemistry , Chondroitin Sulfates/metabolism , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Binding Sites , Amino Acid Sequence , Sequence Alignment , Chondroitin Lyases/chemistry , Chondroitin Lyases/metabolism , Chondroitin Lyases/geneticsABSTRACT
Autophagy is a cellular catabolic process characterized by the formation of double-membrane autophagosomes. Transmission electron microscopy is the most rigorous method to clearly visualize autophagic engulfment and degradation. A large number of studies have shown that autophagy is closely related to the digestion, secretion, and regeneration of gastrointestinal (GI) cells. However, the role of autophagy in GI diseases remains controversial. This article focuses on the morphological and biochemical characteristics of autophagy in GI diseases, in order to provide new ideas for their diagnosis and treatment.
Subject(s)
Gastrointestinal Diseases , Humans , Autophagy , Microscopy, Electron, TransmissionABSTRACT
Alginate is a commercially important polysaccharide composed of mannuronic acid and its C5 differential isomer guluronic acid. Comprehensive research on alginate and alginate lyases requires efficient and precise analytical methods for alginate oligosaccharides. In this research, high-performance anion exchange chromatography (HPAEC) in parallel with pulsed amperometric detection (PAD) and mass spectrometry (MS) was applied to the analysis of oligosaccharides obtained by alginate lyase. By optimizing the chromatographic conditions including mobile phase concentration, flow rate, and elution gradient, the analysis of a single sample could be completed in 30 min. Seven unsaturated alginate oligosaccharides were separated and identified through their analysis time observed with PAD, including all structurally different unsaturated disaccharides and trisaccharides. The quantitative analysis of seven oligosaccharides was performed based on the quantitative capability of PAD. The method exhibited adequate linearity and precision parameters. All the calibration curves showed good linearity at least in the concentration range of 0.002 to 0.1 mg/mL. The HPAEC-PAD/MS method provides a general and efficient online method to analyze alginate oligosaccharides.
Subject(s)
Alginates , Mass Spectrometry , Oligosaccharides , Alginates/chemistry , Oligosaccharides/analysis , Oligosaccharides/chemistry , Chromatography, Ion Exchange/methods , Mass Spectrometry/methods , Chromatography, High Pressure Liquid/methods , Polysaccharide-Lyases/chemistry , Polysaccharide-Lyases/metabolism , Hexuronic Acids/chemistry , Hexuronic Acids/analysis , Limit of DetectionABSTRACT
In recent years, the wide application of mannan has driven the demand for the exploration of mannanase. As one of the main components of hemicellulose, mannan is an important polysaccharide that ruminants need to degrade and utilize, making rumen a rich source of mannanases. In this study, gene mining of mannanases was performed using bioinformatics, and potential dual-catalytic domain mannanases were heterologously expressed to analyze their properties. The hydrolysis pattern and enzymatic products were identified by liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS). A dual-catalytic domain mannanase Man26/5 with the same function as the substrate was successfully mined from the genome of cattle rumen microbiota. Compared to the single-catalytic domain, its higher thermal stability (≤50 °C) and catalytic efficiency confirm the synergistic effect between the two catalytic domains. It exhibited a unique "crab-like" structure where the CBM located in the middle is responsible for binding, and the catalytic domains at both ends are responsible for cutting. The exploration of its multidomain structure and synergistic patterns could provide a reference for the artificial construction and molecular modification of enzymes.
Subject(s)
Bacterial Proteins , Catalytic Domain , beta-Mannosidase , Animals , Cattle , Bacteria/enzymology , Bacteria/genetics , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , beta-Mannosidase/genetics , beta-Mannosidase/chemistry , beta-Mannosidase/metabolism , Enzyme Stability , Hydrolysis , Kinetics , Mannans/chemistry , Mannans/metabolism , Rumen/microbiology , Substrate SpecificitySubject(s)
Carcinoma, Hepatocellular , Hepatitis B, Chronic , Liver Neoplasms , Humans , Carcinoma, Hepatocellular/etiology , Carcinoma, Hepatocellular/epidemiology , Liver Neoplasms/etiology , Liver Neoplasms/epidemiology , Hepatitis B, Chronic/complications , Fatty Liver/complications , Fatty Liver/epidemiology , Risk FactorsABSTRACT
BACKGROUND: As a traditional Chinese herbal medicine, Schisandra chinensis exhibits various effects such as liver protection, blood sugar regulation, blood lipid regulation, immune function regulation, antidepressant activity, etc. However, because of its intricate composition, diverse origins, and medicinal effects depending on complex compound groups, there are differences in the lignan composition of S. chinensis from different origins. Therefore, it is currently difficult to evaluate the quality of medicinal materials from plants of different origins using a single qualitative quality control index. PURPOSE: This paper aims to investigate the potential relationship between the lignan components of S. chinensis from different origins and to establish stable assessment indices for determining the lignan content of S. chinensis from multiple perspectives. METHODS: In this study, we collected S. chinensis samples of seven major origins in China, and randomly sampled 6-9 batches of each origin for a total of 60 batches. The lignan content was determined by HPLC, and its distribution law of the ratio of each lignan component of S. chinensis to Schisandrol A content was analyzed. Combining network pharmacology and differential analysis between samples, the stable and effective substances used as quality markers were determined. RESULTS: There were some correlations among the lignan contents of S. chinensis, some correlations between schisandrin A and other lignans of S. chinensis could be determined. The ratio of each component to the indicator component schisandrol A was evenly distributed and reflected the lignan content of S. chinensis to some extent. Four substances (schisandrol A, schisandrol B, schisantherin A, and schisandrin C) were determined by network pharmacology combined with the analysis results of HCA, PCA and PLS-DA to further optimize the model. They displayed a strong connection with the core target, a large contribution rate to the principal components, and a stable content in each batch of samples, suggesting that these components may be the main active substances of S. chinensis lignans. Therefore, they could be used as main indicators evaluating the advantages and disadvantages of S. chinensis by examining the consistency of component proportions. CONCLUSION: This method can intuitively evaluate the content of main lignans in S. chinensis. This quality assessment model is an exploration of the multi-component comprehensive evaluation system of S. chinensis, providing a new concept for the quality evaluation system of Chinese herbal medicines.
Subject(s)
Cyclooctanes , Drugs, Chinese Herbal , Lignans , Schisandra , Schisandra/chemistry , Lignans/analysis , Drugs, Chinese Herbal/chemistry , Drugs, Chinese Herbal/analysis , Chromatography, High Pressure Liquid/methods , Cyclooctanes/analysis , China , Polycyclic Compounds/analysis , Dioxoles/analysis , Quality Control , Principal Component AnalysisABSTRACT
In recent years, corneal refractive surgery has been widely used in clinics as an effective means to restore vision and improve the quality of life. When choosing myopia-refractive surgery, it is necessary to comprehensively consider the differences in equipment and technology as well as the specificity of individual patients, which heavily depend on the experience of ophthalmologists. In our study, we took advantage of machine learning to learn about the experience of ophthalmologists in decision-making and assist them in the choice of corneal refractive surgery in a new case. Our study was based on the clinical data of 7,081 patients who underwent corneal refractive surgery between 2000 and 2017 at the Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences. Due to the long data period, there were data losses and errors in this dataset. First, we cleaned the data and deleted the samples of key data loss. Then, patients were divided into three groups according to the type of surgery, after which we used SMOTE technology to eliminate imbalance between groups. Six statistical machine learning models, including NBM, RF, AdaBoost, XGBoost, BP neural network, and DBN were selected, and a ten-fold cross-validation and grid search were used to determine the optimal hyperparameters for better performance. When tested on the dataset, the multi-class RF model showed the best performance, with agreement with ophthalmologist decisions as high as 0.8775 and Macro F1 as high as 0.8019. Furthermore, the results of the feature importance analysis based on the SHAP technique were consistent with an ophthalmologist's practical experience. Our research will assist ophthalmologists in choosing appropriate types of refractive surgery and will have beneficial clinical effects.
Subject(s)
Myopia , Refractive Surgical Procedures , Humans , Visual Acuity , Quality of Life , Myopia/surgery , Machine LearningABSTRACT
Double fertilization in many flowering plants (angiosperms) often occurs during the hot summer season, but the mechanisms that enable angiosperms to adapt specifically to high temperatures are largely unknown. The actin cytoskeleton is essential for pollen germination and the polarized growth of pollen tubes, yet how this process responds to high temperatures remains unclear. Here, we reveal that the high thermal stability of 11 Arabidopsis (Arabidopsis thaliana) actin-depolymerizing factors (ADFs) is significantly different: ADFs that specifically accumulate in tip-growing cells (pollen and root hairs) exhibit high thermal stability. Through ancestral protein reconstruction, we found that subclass II ADFs (expressed specifically in pollen) have undergone a dynamic wave-like evolution of the retention, loss, and regeneration of thermostable sites. Additionally, the sites of AtADF7 with high thermal stability are conserved in ADFs specific to angiosperm pollen. Moreover, the high thermal stability of ADFs is required to regulate actin dynamics and turnover at high temperatures to promote pollen germination. Collectively, these findings suggest strategies for the adaptation of sexual reproduction to high temperature in angiosperms at the cell biology level.
Subject(s)
Arabidopsis Proteins , Arabidopsis , Actin Depolymerizing Factors/metabolism , Actins/metabolism , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Temperature , Germination/genetics , Arabidopsis/metabolism , Pollen/metabolism , Pollen TubeABSTRACT
G-specific alginate lyases are important tools for alginate fragment biodegradation and oligosaccharide production, which have great potential in alginate refining research. In this research, a novel G-specific alginate lyase Aly7Ce was cloned, expressed, and characterized, with the optimal reaction conditions at 30 °C and pH 8.0. By employing the UPSEC-VWD-MS method, Aly7Ce was confirmed as a random endoacting alginate lyase. Its minimum substrate was tetrasaccharide, and the final product majorly consisted of disaccharide to tetrasaccharide. HPAEC-PAD/MS method was employed to investigate the structurally different unsaturated alginate oligosaccharides. The substrate recognition and subsite specificity of Aly7Ce were revealed by detecting the oligosaccharide pattern in the enzymatic products with oligosaccharides or polysaccharides as substrates. Aly7Ce mainly attacked the second glycosidic linkage from the nonreducing end of oligosaccharide substrates. The subsite specificity of Aly7Ce was revealed as -2 (M/G), - 1 (G), + 1 (M/G), and +2 (M/G). The regular oligosaccharide products of Aly7Ce could be applied for the efficient preparation of ΔG, ΔGG, and ΔGGG with high purity. The G-specific alginate lyase Aly7Ce with a well-defined product composition and action pattern provided a novel tool for the modification and structural elucidation of alginate, as well as for the targeted preparation of oligosaccharides.
Subject(s)
Polysaccharide-Lyases , Polysaccharides , Polysaccharide-Lyases/chemistry , Oligosaccharides/metabolism , Alginates/chemistry , Substrate Specificity , Hydrogen-Ion Concentration , Bacterial Proteins/metabolismABSTRACT
BACKGROUND: Alginate lyases are important tools for alginate biodegradation and oligosaccharide production, which have great potential in food and biofuel fields. The alginate polysaccharide utilization loci (PUL) typically encode a series of alginate lyases with a synergistic action pattern. Exploring valuable alginate lyases and revealing the synergistic effect of enzymes in the PUL is of great significance. RESULTS: An alginate PUL was discovered from the marine bacterium Wenyingzhuangia fucanilytica CZ1127T , and a repertoire of alginate lyases within it was cloned, expressed and characterized. The four alginate lyases in PUL demonstrated similar optimal reaction conditions: maximum enzyme activity at 35-50 °C and pH 8.0-9.0. The results of action pattern indicated that they were two PL7 endolytic bifunctional enzymes (Aly7A and Aly7B), a PL6 exolytic bifunctional enzyme (Aly6A) and a PL17 exolytic M-specific enzyme (Aly17A). Ultra-performance liquid chromatography-mass spectrometry was employed to reveal the synergistic effect of the four enzymes. The end products of Aly7A were further degraded by Aly7B and eventually generated oligosaccharides, from disaccharide to heptasaccharide. The oligosaccharide products were completely degraded to monosaccharides by Aly6A, but it was unable to directly degrade alginate. Aly17A could also produce monosaccharides by cleaving the M-blocks of oligosaccharide products, as well as the M-blocks of polysaccharides. The combination of these enzymes resulted in the complete degradation of alginate to monosaccharides. CONCLUSION: A new alginate PUL was mined and four novel alginate lyases in the PUL were expressed and characterized. The four cooperative alginate lyases provide novel tools for alginate degradation and biological fermentation. © 2023 Society of Chemical Industry.
Subject(s)
Alginates , Flavobacteriaceae , Alginates/metabolism , Flavobacteriaceae/metabolism , Monosaccharides , Oligosaccharides/metabolism , Substrate Specificity , Hydrogen-Ion ConcentrationABSTRACT
BACKGROUND: A supportive home environment is critical to the safety and quality of life of older adults. Home modification is an effective way to build a supportive home environment for older adults' aging in place. However, there is a lack of knowledge on older adults' need for home modifications in China. METHODS: We conducted a cross-sectional survey in three provinces of China (Hubei, Hunan, and Henan) using stratified and cluster sampling methods in 2021. A total of 5485 older adults aged 60 and over were included. The outcome variables were: need for home modifications, level of need, and type of modification needed. Exposure variables included: demographic and socioeconomic characteristics, as well as health conditions. Logistic and Poisson regressions were applied to examine the needs for home modifications and its associated factors. RESULTS: Nearly 30% of the older adults needed home modifications. The most common choice of home modification was the need for handrails at the bedside, toilet, or threshold (31.64%), and paving un-slip tiles or vinyl flooring (17.45%). Age (IRR = 1.01, P < 0.001), education (IRR = 1.11, P < 0.01), and level of assistance (IRR = 2.31, P < 0.001) were more likely to be positively associated with needs for modification. Participants in the age group of 70 to 79 years, with primary school education, and low-level physically dependent had significantly higher needs for modifications than those of advanced age, lower level of education, or higher level of physically dependent (p < 0.01). CONCLUSIONS: The overall need for home modifications in China is low. Home modification programs are needed to tailor individuals' needs and provide services to those with the most home modification need.