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Objective: This systematic review was conducted to evaluate the efficacy and safety of continuous nursing care for the recovery of joint function in older adults with total hip or knee arthroplasty. Methods: Randomized controlled trials and cohort studies of continuous nursing in older patients after joint replacement were searched from the database of Cochrane Library, Web of Science, PubMed, and Embase from their establishment to October 25, 2023. After literature screening, two researchers completed data extraction, and the risk of bias was assessed using the Cochrane risk-of-bias tool. The risk analysis included in cohort studies was based on the Newcastle-Ottawa Scale (NOS). Results: The study included a total of 15 articles, comprising 34,186 knee and hip replacement patients. In this review, the effects of continuous nursing on the recovery of joint function of knee replacement and hip replacement in older adults were classified and discussed. Continuous nursing interventions targeted for total hip replacement could greatly increase the range of joint mobility, enhance muscle strength during hip movements like flexion, extension, and abduction, maintain joint stability, relieve pain, improve daily activities, and lower the risk of complications. For older patients with knee arthroplasty, continuous nursing programs could markedly improve knee motion range, joint flexion, joint stability, daily activities, and pain management. Despite the implementation of interventions, the incidence of complications caused by total knee replacement did not decrease. Out of all the studies reviewed, only one used a theoretical framework for interventions provided to patients during the postoperative period of hip arthroplasty. The overall quality of the included studies was very high. Conclusion: Continuous nursing can effectively improve the joint function of older patients after joint replacement. However, its effectiveness in terms of clinical outcomes, patient satisfaction, and medical cost of associated continuous nursing needs to be further clarified. In addition, continuous nursing has no significant advantage in the safety of postoperative complications and readmission rates in older adults after knee joint replacement. To enhance the efficacy and safety of continuous nursing effectively, it is crucial to refine the continuous nursing program in the future, thereby elevating the quality of nursing services.
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The riparian zone is an important location of nitrogen removal in the terrestrial and aquatic ecosystems. Many studies have focused on the nitrogen removal efficiency and one or two nitrogen removal processes in the riparian zone, and less attention has been paid to the interaction of different nitrogen transformation processes and the impact of in situ environmental conditions. The molecular biotechnology, microcosm culture experiments and 15N stable isotope tracing techniques were used in this research at the riparian zone in Weinan section of the Wei River, to reveal the nitrogen removal mechanism of riparian zone with multi-layer lithologic structure. The results showed that the nitrogen removal rate in the riparian zone was 4.14-35.19 µmol·N·kg-1·h-1. Denitrification, dissimilatory reduction to ammonium (DNRA) and anaerobic ammonium oxidation (anammox) jointly achieved the natural attenuation process of nitrogen in the riparian zone, and denitrification was the dominant process (accounting for 59.6%). High dissolved organic nitrogen and nitrate ratio (DOC:NO3-) would promote denitrification, but when the NO3- content was less than 0.06 mg/kg, DNRA would occur in preference to denitrification. Furthermore, the abundances of functional genes (norB, nirS, nrfA) and anammox bacterial 16S rRNA gene showed similar distribution patterns with the corresponding nitrogen transformation rates. Sedimentary NOX-, Fe(II), dissolved organic carbon (DOC) and the nitrogen transformation functional microbial abundance were the main factors affecting nitrogen removal in the riparian zone. Fe (II) promoted NO3- attenuation through nitrate dependent ferrous oxidation process under microbial mediation, and DOC promotes NO3- attenuation through enhancing DNRA effect. The results of this study can be used for the management of the riparian zone and the prevention and control of global nitrogen pollution.
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Purpose To determine whether ezrin regulates Yes-associated protein (YAP) and programed cell death ligand-1 (PD-L1), which are involved in the invasion and metastasis of non-small cell lung cancer (NSCLC). Methods Immunohistochemistry of 164 NSCLC and 16 para-cancer tissues was performed to detect ezrin, YAP, and PD-L1 expression. Further, H1299 and A549 cells were transfected with lentivirus, and then colony formation, CCK8, transwell, and wound-healing assays were used to assess cell proliferation, migration, and invasion. RT-qPCR and western blotting were used for quantitative analysis of ezrin, PD-L1, and YAP expression. Moreover, the role of ezrin in tumor growth was assessed in vivo, and immunohistochemistry and western blotting were performed to evaluate changes in ezrin expression in mouse samples. Results The positive protein expression rates of these molecules in NSCLC were as follows: ezrin, 43.9% (72/164); YAP, 54.3% (89/164); and PD-L1, 47.6% (78/164); these were higher than those in normal lung tissues. Moreover, YAP and ezrin expression positively correlated with PD-L1 expression. Ezrin promoted proliferation, migration, invasion, and expression of YAP and PD-L1in NSCLC. Inhibition of ezrin expression reduced the effects of ezrin on cell proliferation, migration, invasion, inhibited the expression of YAP and PD-L1, and obviously reduced experimental tumor volume in vivo. Conclusions Ezrin is overexpressed in NSCLC patients and correlates with PD-L1 and YAP expression. Ezrin regulates YAP and PD-L1 expression. Inhibition of ezrin delayed NSCLC progression (AU)
Subject(s)
Animals , Mice , Carcinoma, Non-Small-Cell Lung/pathology , Lung Neoplasms/pathology , Gene Expression Regulation, Neoplastic , B7-H1 Antigen/metabolism , Cell Line, Tumor , Cell ProliferationABSTRACT
We propose an ultra-wideband photonic compressive receiver based on random codes shifting with image-frequency distinction. By shifting the center frequencies of two random codes in large frequency range, the receiving bandwidth is flexibly expanded. Simultaneously, the center frequencies of two random codes are slightly different. This difference is used to distinguish the "fixed" true RF signal from the differently located image-frequency signal. Based on this idea, our system solves the problem of limited receiving bandwidth of existing photonic compressive receivers. In the experiments, with two channels of only 780-MHz outputs, the sensing capability in the range of 11-41â GHz has been demonstrated. A multi-tone spectrum and a sparse radar-communication spectrum, composed of a linear frequency modulated (LFM) signal, a quadrature phase-shift keying (QPSK) signal and a single-tone signal, are both recovered.
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PURPOSE: To determine whether ezrin regulates Yes-associated protein (YAP) and programed cell death ligand-1 (PD-L1), which are involved in the invasion and metastasis of non-small cell lung cancer (NSCLC). METHODS: Immunohistochemistry of 164 NSCLC and 16 para-cancer tissues was performed to detect ezrin, YAP, and PD-L1 expression. Further, H1299 and A549 cells were transfected with lentivirus, and then colony formation, CCK8, transwell, and wound-healing assays were used to assess cell proliferation, migration, and invasion. RT-qPCR and western blotting were used for quantitative analysis of ezrin, PD-L1, and YAP expression. Moreover, the role of ezrin in tumor growth was assessed in vivo, and immunohistochemistry and western blotting were performed to evaluate changes in ezrin expression in mouse samples. RESULTS: The positive protein expression rates of these molecules in NSCLC were as follows: ezrin, 43.9% (72/164); YAP, 54.3% (89/164); and PD-L1, 47.6% (78/164); these were higher than those in normal lung tissues. Moreover, YAP and ezrin expression positively correlated with PD-L1 expression. Ezrin promoted proliferation, migration, invasion, and expression of YAP and PD-L1in NSCLC. Inhibition of ezrin expression reduced the effects of ezrin on cell proliferation, migration, invasion, inhibited the expression of YAP and PD-L1, and obviously reduced experimental tumor volume in vivo. CONCLUSIONS: Ezrin is overexpressed in NSCLC patients and correlates with PD-L1 and YAP expression. Ezrin regulates YAP and PD-L1 expression. Inhibition of ezrin delayed NSCLC progression.
Subject(s)
Carcinoma, Non-Small-Cell Lung , Lung Neoplasms , Animals , Mice , Carcinoma, Non-Small-Cell Lung/pathology , Lung Neoplasms/pathology , B7-H1 Antigen/metabolism , Cell Line, Tumor , Cell Proliferation , Gene Expression Regulation, NeoplasticABSTRACT
BACKGROUND: Gluconobacter oxydans, is used in biotechnology because of its ability to oxidize a wide variety of carbohydrates, alcohols, and polyols in a stereo- and regio-selective manner by membrane-bound dehydrogenases located in periplasmic space. These reactions obey the well-known Bertrand-Hudson's rule. In our previous study (BBA-General Subjects, 2021, 1865:129740), we discovered that Gluconobacter species, including G. oxydans and G. cerinus strain can regio-selectively oxidize the C-3 and C-5 hydroxyl groups of D-galactitol to rare sugars D-tagatose and L-xylo-3-hexulose, which represents an exception to Bertrand Hudson's rule. The enzyme catalyzing this reaction is located in periplasmic space or membrane-bound and is PQQ (pyrroloquinoline quinine) and Ca2+-dependent; we were encouraged to determine which type of enzyme(s) catalyze this unique reaction. METHODS: Enzyme was identified by complementation of multi-deletion strain of Gluconobacter oxydans 621H with all putative membrane-bound dehydrogenase genes. RESULTS AND CONCLUSIONS: In this study, we identified this gene encoding the membrane-bound PQQ-dependent dehydrogenase that catalyzes the unique galactitol oxidation reaction in its 3'-OH and 5'-OH. Complement experiments in multi-deletion G. oxydans BP.9 strains established that the enzyme mSLDH (encoded by GOX0855-0854, sldB-sldA) is responsible for galactitol's unique oxidation reaction. Additionally, we demonstrated that the small subunit SldB of mSLDH was membrane-bound and served as an anchor protein by fusing it to a red fluorescent protein (mRubby), and heterologously expressed in E. coli and the yeast Yarrowia lipolytica. The SldB subunit was required to maintain the holo-enzymatic activity that catalyzes the conversion of D-galactitol to L-xylo-3-hexulose and D-tagatose. The large subunit SldA encoded by GOX0854 was also characterized, and it was discovered that its 24 amino acids signal peptide is required for the dehydrogenation activity of the mSLDH protein. GENERAL SIGNIFICANCE: In this study, the main membrane-bound polyol dehydrogenase mSLDH in G. oxydans 621H was proved to catalyze the unique galactitol oxidation, which represents an exception to the Bertrand Hudson's rule, and broadens its substrate ranges of mSLDH. Further deciphering the explicit enzymatic mechanism will prove this theory.
Subject(s)
Gluconobacter oxydans , L-Iditol 2-Dehydrogenase , Humans , L-Iditol 2-Dehydrogenase/genetics , L-Iditol 2-Dehydrogenase/metabolism , Gluconobacter oxydans/genetics , Gluconobacter oxydans/metabolism , Galactitol/metabolism , Escherichia coli/metabolismABSTRACT
Existing photonic compressive receivers have the problem of resolution deterioration when applied in wide-range radar detection. In this study, we propose a photonic-assisted space-frequency two-dimensional (2D) compressive radar receiver capable of achieving high-resolution detection in wide-range scenarios. For the space dimension, the compression process is realized by employing a spatially adaptive photonic projection basis, which guarantees complete mapping of arbitrarily delayed echoes-the key to high-resolution wide-range detection. For the frequency dimension, photonic compressive sensing is employed to further compress the bandwidth of the projected sparse signal. Therefore, the proposed system can achieve wide-range radar detection without resolution deterioration with compressed output. Herein, with two channels of 630 MHz outputs, high-resolution distance detection within a range of 21 km with a resolution of up to 2.3 cm is achieved. Moreover, inverse synthetic aperture radar (ISAR) imaging of two sets of four-point turntables distributed within the range of 21 km with a resolution of 2.3 cm × 5.7 cm is realized. The proposed photonic-assisted 2D compressive radar receiver is a viable solution to overcome the tradeoff between detection resolution and range of existing photonic compressive receivers, which indicates a path for the further development of high-resolution wide-range radar detection.
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Aluminum neurotoxicity impairs learning and memory ability, but the molecular mechanism has not been elucidated. The aim of this study was to examine the role of phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling in regulating the expression of synaptic plasticity-related proteins (PRPs) and p-tau deposition to explore the mechanism underlying aluminum-induced neurotoxicity. We constructed a sub-chronic aluminum-exposed Sprague Dawley (SD) rat model to assess aluminum neurotoxicity in vivo. The learning and memory abilities of rats were examined using the Morris water maze test. We also assessed the effect of aluminum in vitro using rat pheochromocytoma (PC12) cells. To explore the role of PI3K/Akt/mTOR signaling in aluminum neurotoxicity, we used the PI3K inhibitor wortmannin and the mTOR inhibitor rapamycin in aluminum-treated PC12 cells. Protein expression was examined by western blotting. Aluminum disrupted the learning and memory abilities of SD rats. Mechanistically, aluminum reduced the levels of the synaptic PRPs (cAMP-response element binding protein (CREB), glutamate receptor 1 (GluR1), glutamate receptor 2 (GluR2), and postsynaptic density protein 95 (PSD-95), and it increased p-tau deposition in the hippocampus of SD rats. We observed similar results in aluminum-treated PC12 cells. Further, PI3K/Akt/mTOR signaling was abnormally activated in aluminum-treated PC12 cells, and treatment with rapamycin reversed the decrease in synaptic PRPs levels and the increase in p-tau deposition. In conclusion, the activation of PI3K/Akt/mTOR signaling reduces the levels of synaptic PRPs and increases p-tau deposition induced by aluminum. Therefore, the PI3K/Akt/mTOR pathway participates in the mechanism of aluminum neurotoxicity.
Subject(s)
Neurotoxicity Syndromes , Phosphatidylinositol 3-Kinases , Aluminum/toxicity , Animals , Disks Large Homolog 4 Protein , Mammals/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Rats , Rats, Sprague-Dawley , Receptors, Glutamate , Sirolimus/pharmacology , TOR Serine-Threonine Kinases/metabolism , WortmanninABSTRACT
Interfacial free energy is a quantitative basis for explaining and predicting interfacial behavior that is ubiquitous in nature. The contact angle (CA) method can determine the surface free energy (γ) as well as Lifshitz-van der Waals (γLW) and Lewis acid/base (γ+/γ-) components of a solid material from its CAs with a set of known test liquids according to the extended Young-Dupré equation. However, the reliability of the "known" parameters of the test liquids is questioned due to the long-neglected surface roughness effect during calibration of the liquids. This study proposed a simple and practicable two-step approach to correct the energy parameters of several test liquids by incorporating Wenzel's surface roughness relationship into CA measurement. Step 1: water and two apolar liquids (diiodomethane and α-bromonaphthalene) were used as benchmarks to calibrate the surface roughness and energy parameters of two reference solids [apolar poly(tetrafluoroethylene) and monopolar poly(methyl methacrylate)], and step 2: the reference solids were used to calibrate any other test liquids by solving the energy parameters from their CAs in the extended Young-Dupré-Wenzel model. Monte Carlo simulation was used to evaluate error transmission and robustness of the model solutions. The obtained energy parameters (γLW/γ+/γ-) of four test liquids (dimethyl sulfoxide, formamide, ethylene glycol, and glycerol) are 28.01/13.68/4.67, 34.95/3.53/37.62, 26.26/7.51/15.74, and 32.99/9.24/26.02 mJ/m2, respectively, and different from the literature values. The liquids were applied to characterize an example solid surface with true γLW/γ+/γ- values of 28.00/1.00/8.00 mJ/m2 and a roughness index (r) of 1.60. Without correction of the liquid parameters, the calculated surface energy, hydration energy, and hydrophobic attraction energy of the solid sample can deviate by 50, 13, and 27%, respectively. This proves the necessity of correcting parameters of the test liquids before they can be used in CA and interfacial energy studies in the presence of surface roughness.
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Kluyveromyces marxianus is an emerging non-conventional food-grade yeast that is generally isolated from diverse habitats, like kefir grain, fermented dairy products, sugar industry sewage, plants, and sisal leaves. A unique set of beneficial traits, such as fastest growth, thermotolerance, and broad substrate spectrum (i.e., hemi-cellulose hydrolysates, xylose, l-arabinose, d-mannose, galactose, maltose, sugar syrup molasses, cellobiose, and dairy industry) makes this yeast a particularly attractive host for applications in a variety of food and biotechnology industries. In contrast to Saccharomyces cerevisiae, most of the K. marxianus strains are apparently Crabtree-negative or having aerobic-respiring characteristics, and unlikely to endure aerobic alcoholic fermentation. This is a desirable phenotype for the large-scale biosynthesis of products associated with biomass formation because the formation of ethanol as an undesirable byproduct can be evaded under aerobic conditions. Herein, we discuss the current insight into the potential applications of K. marxianus as a robust yeast cell factory to produce various industrially pertinent enzymes, bioethanol, cell proteins, probiotic, fructose, and fructo-oligosaccharides, and vaccines, with excellent natural features. Moreover, the biotechnological improvement and development of new biotechnological tools, particularly CRISPR-Cas9-assisted precise genome editing in K. marxianus are delineated. Lastly, the ongoing challenges, concluding remarks, and future prospects for expanding the scope of K. marxianus utilization in modern biotechnology, food, feed, and pharmaceutical industries are also thoroughly vetted. In conclusion, it is critical to apprehend knowledge gaps around genes, metabolic pathways, key enzymes, and regulation for gaining a complete insight into the mechanism for producing relevant metabolites by K. marxianus.
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PURPOSE: c-MYC plays an important role in regulating cellular growth and apoptosis, and it is aberrantly expressed in many human malignancies. Although c-MYC has been extensively investigated in Burkitt lymphoma and diffuse large B cell lymphoma, little has been reported in anaplastic large cell lymphoma (ALCL). The aim of this study was to investigate the expression and genetic alterations of c-MYC in primary systemic ALCL, characterize its clinicopathologic features and immunophenotypes, and discuss their implications in prognosis. METHODS: Tissue microarrays using samples from 85 ALCL patients were used to evaluate expression of c-MYC and anaplastic lymphoma kinase (ALK). c-MYC and ALK genetic alterations were detected using fluorescence in situ hybridization. The Kaplan-Meier and multivariate Cox regression methods were used for survival analysis. RESULTS: c-MYC was expressed in 24 of 85 samples (28.2%), and ALK was expressed in 54 (63.5%). c-MYC and ALK were co-expressed in 16 samples (18.8%). c-MYC expression and c-MYC and ALK co-expression increased with ALCL clinical stages and the International Prognostic Index (IPI) score (p < 0.05). Fifty of the samples (58.8%) had ALK rearrangement, and 18 (22.1%) had aneuploidy. c-MYC rearrangement was not detected, but aneuploidy was observed in 19 cases (22.4%). c-MYC aneuploidy was significantly different based on c-MYC expression and the IPI score (p < 0.05). c-MYC was a significant independent prognostic factor for progression-free survival and overall survival in patients with ALCL. CONCLUSION: c-MYC protein expression and c-MYC aneuploidy could predict worse survival in patients with ALCL.
Subject(s)
Anaplastic Lymphoma Kinase/genetics , Lymphoma, Large-Cell, Anaplastic/genetics , Lymphoma, Large-Cell, Anaplastic/pathology , Proto-Oncogene Proteins c-myc/genetics , Adolescent , Adult , Aged , Anaplastic Lymphoma Kinase/metabolism , Aneuploidy , Child , Female , Humans , In Situ Hybridization, Fluorescence , Lymphoma, Large-Cell, Anaplastic/mortality , Male , Middle Aged , Prognosis , Proto-Oncogene Proteins c-myc/metabolism , Survival Analysis , Young AdultABSTRACT
PURPOSE: To investigate PD-L1 protein expression and gene amplification in lung squamous cell carcinoma (LUSC) and analyse their correlation with the clinicopathological characteristics and prognosis of LUSC patients. PATIENTS AND METHODS: Tissue samples from 164 LUSC patients were collected. PD-L1 protein was detected by immunochemistry (IHC), and PD-L1 gene amplification was investigated by fluorescence in situ hybridization in LUSC patients. RESULTS: The positive expression rate of PD-L1 in LUSC was 47.6% (78/164), and the amplification rate of PD-L1 was 6.7% (11/164); both rates were higher than those of paratumor tissue. Both PD-L1 positive expression and gene amplification were correlated with clinical stage and lymph node metastasis (P<0.05). PD-L1 protein expression, PD-L1 gene amplification, late stage, lymph node metastasis and distant metastasis were significantly correlated with the prognosis of patients. Among these factors, late stage, lymph node metastasis, PD-L1 protein expression and PD-L1 gene amplification were independent prognostic factors for LUSC. CONCLUSION: Positive PD-L1 protein expression and gene amplification are involved in the malignant progression and metastasis of LUSC. Both PD-L1 protein expression and gene amplification are associated with poor prognosis.
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The C-X-C motif (CXC) chemokines are a family of chemotactic molecules that have been identified as potential prognostic markers and prospective therapeutic targets for many kinds of cancer types. Increasing evidence shows that CXC chemokines are associated with the progression of colorectal cancer (CRC); however, the correlations of CXC chemokines with prognostic and immune infiltrates in CRC remain to be clarified. In this study, we analyzed the mRNA expression level, prognostic data and immune infiltrates of CXC chemokines in CRC patients from the Gene Expression Profiling Interactive Analysis, Oncomine, cBioPortal and databases using GeneMANIA, STRING, DAVID 6.8, and TIMER. Our results showed that CXCL1/2/3/4/5/8/9/10/11/13/14/16 were significantly overexpressed in CRC tissues. Furthermore, expression of CXCL1/2/3/9/10/11 was associated with tumor stage in CRC. A significant association was also identified between the co-expression of CXCL16 with EGFR, KRAS and NRAS. In addition, the survival analysis suggested that high CXCL2/3/8/9/10/11/14 expression is correlated with clinical outcomes of CRC patients. Moreover, a significant association was observed between the CXCL8/9/10/11 expression and immune infiltration in colonic and rectal adenocarcinoma. Overall, CXC chemokines are not only implicated as prognostic biomarkers for CRC patients, but may also influence the immune status of CRC tissues.
Subject(s)
Adenocarcinoma/immunology , Adenocarcinoma/pathology , Chemokines, CXC/analysis , Chemokines, CXC/metabolism , Colorectal Neoplasms/immunology , Colorectal Neoplasms/pathology , Biomarkers, Tumor/analysis , Databases, Genetic , Gene Expression Profiling , Gene Expression Regulation, Neoplastic/genetics , Humans , Prognosis , Prospective Studies , Survival AnalysisABSTRACT
N 6-methyladenosine (m6A) is the most abundant internal modification in eukaryotic messenger RNAs (mRNAs). m6A RNA methylation is involved in all stages of RNA life cycle, from RNA processing, nuclear output, translation regulation to RNA degradation, indicating that m6A has various functions affecting RNA metabolism positively or negatively. Reading proteins are vital in regulating the translation and stability of m6A mRNAs positively or negatively. Recent studies have enhanced the understanding of the molecular mechanism of the YT521-B homology (YTH) domain family and the modification of m6A. This study aimed to review the specific mechanisms, functions, and interactions of the YTH domain protein family. It also discussed future research directions, thus providing new ideas for the clinical diagnosis and targeted therapy of cancer.
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BACKGROUND: In acetic acid bacteria such as Gluconobacter oxydans or Gluconobacter cerinus, pyrroloquinoline quinone (PQQ) in the periplasm serves as the redox cofactor for several membrane-bound dehydrogenases that oxidize polyhydric alcohols to rare sugars, which can be used as a healthy alternative for traditional sugars and sweeteners. These oxidation reactions obey the generally accepted Bertrand Hudson's rule, in which only the polyhydric alcohols that possess cis d-erythro hydroxyl groups can be oxidized to 2-ketoses using PQQ as a cofactor, while the polyhydric alcohols excluding cis d-erythro hydroxyl groups ruled out oxidation by PQQ-dependent membrane-bound dehydrogenases. METHODS: Membrane fractions of G. oxydans were prepared and used as a cell-free catalyst to oxidize galactitol, with or without PQQ as a cofactor. RESULTS: In this study, we reported an interesting oxidation reaction that the polyhydric alcohols galactitol (dulcitol), which do not possess cis d-erythro hydroxyl groups, can be oxidized by PQQ-dependent membrane-bound dehydrogenase(s) of acetic acid bacteria at the C-3 and C-5 hydroxyl groups to produce rare sugars l-xylo-3-hexulose and d-tagatose. CONCLUSIONS: This reaction may represent an exception to Bertrand Hudson's rule. GENERAL SIGNIFICANCE: Bertrand Hudson's rule is a well-known theory in polyhydric alcohols oxidation by PQQ-dependent membrane-bound dehydrogenase in acetic acid bacteria. In this study, galactitol oxidation by a PQQ-dependent membrane-bound dehydrogenase represents an exception to the Bertrand Hudson's rule. Further identification of the associated enzymes and deciphering the explicit enzymatic mechanism will prove this theory.
Subject(s)
Acetic Acid/metabolism , Galactitol/metabolism , Gluconobacter/metabolism , Hexoses/metabolism , Ketoses/metabolism , Bacterial Proteins/metabolism , Gluconobacter/enzymology , Oxidation-Reduction , Oxidoreductases/metabolism , PQQ Cofactor/metabolismABSTRACT
An amendment to this paper has been published and can be accessed via the original article.
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BACKGROUND: Functional sugar alcohols have been widely used in the food, medicine, and pharmaceutical industries for their unique properties. Among these, erythritol is a zero calories sweetener produced by the yeast Yarrowia lipolytica. However, in wild-type strains, erythritol is produced with low productivity and yield and only under high osmotic pressure together with other undesired polyols, such as mannitol or d-arabitol. The yeast is also able to catabolize erythritol in non-stressing conditions. RESULTS: Herein, Y. lipolytica has been metabolically engineered to increase erythritol production titer, yield, and productivity from glucose. This consisted of the disruption of anabolic pathways for mannitol and d-arabitol together with the erythritol catabolic pathway. Genes ZWF1 and GND encoding, respectively, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were also constitutively expressed in regenerating the NADPH2 consumed during erythritol synthesis. Finally, the gene RSP5 gene from Saccharomyces cerevisiae encoding ubiquitin ligase was overexpressed to improve cell thermoresistance. The resulting strain HCY118 is impaired in mannitol or d-arabitol production and erythritol consumption. It can grow well up to 35 °C and retain an efficient erythritol production capacity at 33 °C. The yield, production, and productivity reached 0.63 g/g, 190 g/L, and 1.97 g/L·h in 2-L flasks, and increased to 0.65 g/g, 196 g/L, and 2.51 g/L·h in 30-m3 fermentor, respectively, which has economical practical importance. CONCLUSION: The strategy developed herein yielded an engineered Y. lipolytica strain with enhanced thermoresistance and NADPH supply, resulting in a higher ability to produce erythritol, but not mannitol or d-arabitol from glucose. This is of interest for process development since it will reduce the cost of bioreactor cooling and erythritol purification.
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A novel method was applied to improve biochar properties and its soil application by introducing molasses fermentation wastewater into a maize straw pyrolysis process. In this study, maize straw biochar (MSB) was prepared from maize straw mixed with different amounts (1, 2 and 3 mL g-1 straw, v/w) of molasses fermentation wastewater which contained high organics and nitrogen contents. Characterization results indicated that the yield, carbon content, N/C, and cation exchange capacity (CEC) of MSB increased gradually with the increasing dosage of fermentation wastewater. In addition, the prepared MSB was added into sandy soil with four mixing proportions (1%, 3%, 5% and 10%, w/w) to investigate its effects on plant growth, soil properties and soil catalase activity (CAT) by pot experiments. The results indicated that MSB amendments increased soil pH, soil total organic carbon (TOC) and nutrients contents (TN, TP). It was suggested that 5% biochar proportion in soil derived from maize straw with 2 mL g-1 fermentation wastewater addition was more suitable for ryegrass growth, soil fertility and CAT activity improvement. This study provides a promising way to realize the resource utilization of fermentation wastewater and agricultural wastes at the same time.
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Xylitol is a natural five-carbon sugar alcohol with potential for use in food and pharmaceutical industries owing to its insulin-independent metabolic regulation, tooth rehardening, anti-carcinogenic, and anti-inflammatory, as well as osteoporosis and ear infections preventing activities. Chemical and biosynthetic routes using D-xylose, glucose, or biomass hydrolysate as raw materials can produce xylitol. Among these methods, microbial production of xylitol has received significant attention due to its wide substrate availability, easy to operate, and eco-friendly nature, in contrast with high-energy consuming and environmental-polluting chemical method. Though great advances have been made in recent years for the biosynthesis of xylitol from xylose, glucose, and biomass hydrolysate, and the yield and productivity of xylitol are substantially improved by metabolic engineering and optimizing key metabolic pathway parameters, it is still far away from industrial-scale biosynthesis of xylitol. In contrary, the chemical synthesis of xylitol from xylose remains the dominant route. Economic and highly efficient xylitol biosynthetic strategies from an abundantly available raw material (i.e., glucose) by engineered microorganisms are on the hard way to forwarding. However, synthetic biology appears as a novel and promising approach to develop a super yeast strain for industrial production of xylitol from glucose. After a brief overview of chemical-based xylitol production, we critically analyzed and comprehensively summarized the major metabolic strategies used for the enhanced biosynthesis of xylitol in this review. Towards the end, the study is wrapped up with current challenges, concluding remarks, and future prospects for designing an industrial yeast strain for xylitol biosynthesis from glucose.
Subject(s)
Industrial Microbiology/economics , Metabolic Engineering/economics , Metabolic Engineering/methods , Metabolic Networks and Pathways , Synthetic Biology/economics , Xylitol/biosynthesis , Fermentation , Glucose/metabolism , Industrial Microbiology/methods , Industrial Microbiology/trends , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Sugar Alcohols/metabolism , Synthetic Biology/methods , Synthetic Biology/trends , Xylose/metabolismABSTRACT
A reconfigurable photonic microwave convolver is proposed. The scheme simply consists of the evenly spaced optical carriers (ESOCs), an optical dispersion module (ODM), a wavelength selector (WS), and a balanced photodetector. By adjusting the ESOCs, the dispersion value of the ODM, and the setup of the WS, the proposed convolver is reconfigurable. With the convolver, pulse compressions of the phase-coded microwave waveforms (PCMWs) are realized. Compressions of two PCMWs with different code patterns and respective coding rates of 1.8 and 3.6 Gbit/s are experimentally demonstrated. Full widths at half-maximum (FWHMs) of the main lobe are 0.56 and 0.28 ns, and the peak-to-side lobe ratios are 11.1 and 10.8 dB, respectively. The results are in agreement with the theoretical values. Besides, due to the flexible reconfigurability, it can adapt to various PCMWs by simple operation.