RESUMO
Lithium metal batteries (LMBs) are promising for next-generation high-energy-density batteries owing to the highest specific capacity and the lowest potential of Li metal anode. However, the LMBs are normally confronted with drastic capacity fading under extremely cold conditions mainly due to the freezing issue and sluggish Li+ desolvation process in commercial ethylene carbonate (EC)-based electrolyte at ultra-low temperature (e.g., below -30 °C). To overcome the above challenges, an anti-freezing carboxylic ester of methyl propionate (MP)-based electrolyte with weak Li+ coordination and low-freezing temperature (below -60 °C) is designed, and the corresponding LiNi0.8 Co0.1 Mn0.1 O2 (NCM811) cathode exhibits a higher discharge capacity of 84.2 mAh g-1 and energy density of 195.0 Wh kg-1 cathode than that of the cathode (1.6 mAh g-1 and 3.9 Wh kg-1 cathode ) working in commercial EC-based electrolytes for NCM811â Li cell at -60 °C. Molecular dynamics simulation, Raman spectra, and nuclear magnetic resonance characterizations reveal that rich mobile Li+ and the unique solvation structure with weak Li+ coordination are achieved in MP-based electrolyte, which collectively facilitate the Li+ transference process at low temperature. This work provides fundamental insights into low-temperature electrolytes by regulating solvation structure, and offers the basic guidelines for the design of low-temperature electrolytes for LMBs.
RESUMO
OBJECTIVE: Parapharyngeal metastases (PPM) are rarely observed in patients with well-differentiated thyroid cancer (WDTC). Radioiodine (131 I) therapy has been the main treatment for metastatic and recurrent DTC after thyroidectomy. This study was performed to evaluate the clinicopathological features and long-term outcomes associated with survival of patients with PPM at the end of follow-up. DESIGN: In total, 14,984 consecutive patients with DTC who underwent 131 I therapy after total or near-total thyroidectomy from 2004 to 2021 were retrospectively reviewed. Therapeutic efficacy was evaluated using the Response Evaluation Criteria in Solid Tumours v1.1 and logistic regression analysis. The disease status was determined using dynamic risk stratification. Disease-specific survival (DSS) was assessed using the Kaplan-Meier method and a Cox proportional hazards model. PATIENTS: Seventy-five patients with PPM from WDTC were enroled in this study. Their median age at the initial diagnosis of PPM was 40.2 ± 14.1 years, and the patients comprised 32 men and 43 women (male:female ratio, 1.00:1.34). Of the 75 patients, 43 (57.33%) presented with combined distant metastases. Fifty-seven (76.00%) patients had 131 I avidity and 18 had non-131 I avidity. At the end of follow-up, 22 (29.33%) patients showed progressive disease. Sixteen of the 75 patients died; of the remaining 59 patients, 6 (8.00%) had an excellent response, 6 (8.00%) had an indeterminate response, 10 (13.33%) had an biochemical incomplete response, and 37 (49.33%) had a structural incomplete response. Multivariate analysis confirmed that age at initial PPM diagnosis, the maximal size of PPM, and 131 I avidity had significant effects on progressive disease of PPM lesions (p = .03, p= .02, and p < .01, respectively). The 5- and 10-year DSS rates were 98.49% and 62.10%, respectively. Age of ≥55 years at initial diagnosis of PPM and the presence of concomitant distant metastasis were independently associated with a poor prognosis (p = .03 and p = .04, respectively). CONCLUSION: The therapeutic effect for PPM was closely associated with 131 I avidity, age at initial PPM diagnosis, and maximal size of PPM at the end of follow-up. Age of ≥55 years at initial diagnosis of PPM and the presence of concomitant distant metastasis were independently associated with poor survival.
Assuntos
Radioisótopos do Iodo , Neoplasias da Glândula Tireoide , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Prognóstico , Seguimentos , Radioisótopos do Iodo/uso terapêutico , Estudos Retrospectivos , Neoplasias da Glândula Tireoide/patologia , TireoidectomiaRESUMO
BACKGROUND: While it has been known that human protein kinases mediate most signal transductions in cells and their dysfunction can result in inflammatory diseases and cancers, it remains a challenge to find effective kinase inhibitor as drugs for these diseases. One major challenge is the compensatory upregulation of related kinases following some critical kinase inhibition. To circumvent the compensatory effect, it is desirable to have inhibitors that inhibit all the kinases belonging to the same family, instead of targeting only a few kinases. However, finding inhibitors that target a whole kinase family is laborious and time consuming in wet lab. RESULTS: In this paper, we present a computational approach taking advantage of interpretable deep learning models to address this challenge. Specifically, we firstly collected 9,037 inhibitor bioassay results (with 3991 active and 5046 inactive pairs) for eight kinase families (including EGFR, Jak, GSK, CLK, PIM, PKD, Akt and PKG) from the ChEMBL25 Database and the Metz Kinase Profiling Data. We generated 238 binary moiety features for each inhibitor, and used the features as input to train eight deep neural networks (DNN) models to predict whether an inhibitor is active for each kinase family. We then employed the SHapley Additive exPlanations (SHAP) to analyze the importance of each moiety feature in each classification model, identifying moieties that are in the common kinase hinge sites across the eight kinase families, as well as moieties that are specific to some kinase families. We finally validated these identified moieties using experimental crystal structures to reveal their functional importance in kinase inhibition. CONCLUSION: With the SHAP methodology, we identified two common moieties for eight kinase families, 9 EGFR-specific moieties, and 6 Akt-specific moieties, that bear functional importance in kinase inhibition. Our result suggests that SHAP has the potential to help finding effective pan-kinase family inhibitors.
Assuntos
Antineoplásicos , Neoplasias , Antineoplásicos/uso terapêutico , Receptores ErbB , Humanos , Neoplasias/tratamento farmacológico , Inibidores de Proteínas Quinases/química , Proteínas Proto-Oncogênicas c-aktRESUMO
BACKGROUND: Human protein kinases play important roles in cancers, are highly co-regulated by kinase families rather than a single kinase, and complementarily regulate signaling pathways. Even though there are > 100,000 protein kinase inhibitors, only 67 kinase drugs are currently approved by the Food and Drug Administration (FDA). RESULTS: In this study, we used "merged moiety-based interpretable features (MMIFs)," which merged four moiety-based compound features, including Checkmol fingerprint, PubChem fingerprint, rings in drugs, and in-house moieties as the input features for building random forest (RF) models. By using > 200,000 bioactivity test data, we classified inhibitors as kinase family inhibitors or non-inhibitors in the machine learning. The results showed that our RF models achieved good accuracy (> 0.8) for the 10 kinase families. In addition, we found kinase common and specific moieties across families using the Shapley Additive exPlanations (SHAP) approach. We also verified our results using protein kinase complex structures containing important interactions of the hinges, DFGs, or P-loops in the ATP pocket of active sites. CONCLUSIONS: In summary, we not only constructed highly accurate prediction models for predicting inhibitors of kinase families but also discovered common and specific inhibitor moieties between different kinase families, providing new opportunities for designing protein kinase inhibitors.
Assuntos
Aprendizado de Máquina , Proteínas Quinases , Humanos , Preparações Farmacêuticas , Inibidores de Proteínas Quinases/farmacologia , Estados Unidos , United States Food and Drug AdministrationRESUMO
BACKGROUND: Human protein kinases, the key players in phosphoryl signal transduction, have been actively investigated as drug targets for complex diseases such as cancer, immune disorders, and Alzheimer's disease, with more than 60 successful drugs developed in the past 30 years. However, many of these single-kinase inhibitors show low efficacy and drug resistance has become an issue. Owing to the occurrence of highly conserved catalytic sites and shared signaling pathways within a kinase family, multi-target kinase inhibitors have attracted attention. RESULTS: To design and identify such pan-kinase family inhibitors (PKFIs), we proposed PKFI sets for eight families using 200,000 experimental bioactivity data points and applied a graph convolutional network (GCN) to build classification models. Furthermore, we identified and extracted family-sensitive (only present in a family) pre-moieties (parts of complete moieties) by utilizing a visualized explanation (i.e., where the model focuses on each input) method for deep learning, gradient-weighted class activation mapping (Grad-CAM). CONCLUSIONS: This study is the first to propose the PKFI sets, and our results point out and validate the power of GCN models in understanding the pre-moieties of PKFIs within and across different kinase families. Moreover, we highlight the discoverability of family-sensitive pre-moieties in PKFI identification and drug design.
Assuntos
Doença de Alzheimer , Neoplasias , Humanos , Proteínas Quinases/metabolismo , Transdução de SinaisRESUMO
Polymeric materials implanted in the human body are usually invisible under X-ray, and the mixing of heavy metal salts into polymeric materials by physical compounding often poses compatibility problems. A new iodine-containing cyclic carbonate monomer, 4-iodo-N-(2-oxo-1,3-dioxan-5-yl)benzamide (IBTMC), is synthesized, which has a degradable carbonate group as its basic structural unit and iodine atoms attached to the side chain in the form of covalent bonds. The ring-opening polymerization of IBTMC is achieved at room temperature under the catalysis of the solid superbase 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). The structure and X-ray developing ability of the synthesized polycarbonate are characterized by 1 H-NMR, X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), Gel Permeation Chromatography (GPC), and micro-computed tomography (Micro-CT). The iodine atoms remain bound to the polymer as covalent bonds after a series of reactions and exhibit a high level of X-ray opacity. In vitro degradation experiments of the polymer prove that the polymer is degradable.
Assuntos
Carbonatos , Cimento de Policarboxilato , Humanos , Cimento de Policarboxilato/química , Polimerização , Microtomografia por Raio-XRESUMO
Tobacco is one of the most significant non-food cash crops (Lu et al. 2020). In March 2022, cigar tobacco plants showing characteristic symptoms of vascular discoloration, stem rotting, leaf wilting and rotting were observed in Tengchong city (N 25°3'26â³, E 98°25'6â³) of Yunnan province, China (Fig. S1). The disease incidence was about 5% on cultivar Yunxue 6 in a 33-ha field. Infected stems were collected from Tengchong for pathogen isolation and 16S rDNA sequence analysis was performed as previously described (Lu et al. 2021). Sequence analysis showed that tobacco isolates (GenBank accession numbers: ON795108, ON795107 and ON795106) had an identical sequence with that of the species type strain of Pectobacterium versatile CFBP 6051T and shared the sequence identities of 99.55% and 99.47% with P. carotovorum DSM 30168T and P. parvum s0421T, respectively. Furthermore, phylogenetic analysis showed that tobacco strains were clustered with Pectobacterium versatile CFBP 6051T (Fig. S2a). In API assays, strain 22TC1 was positive for ß-galactosidase activity, reduction of nitrates to nitrites, fermentation of glucose, hydrolysis of esculin and gelatin, assimilation of D-glucose, L-arabinose, D-mannose, D-mannitol, N-acetylglucosamine, malic acid and trisodium citrate; positive for the enzymatic substrates of alkaline phosphatase, leucine arylamidase, acid phosphatase, naphthol-AS-BI-phosphohydrolase, α-galactosidase, ß-galactosidase and α-glucosidase. Furthermore, the average nucleotide identity (ANI) analysis (Richter et al. 2015) showed that strain 22TC1 (GenBank accession number: JAMWYQ000000000) had the highest ANIb score of 96.76% and ANIm value of 97.19% with P. versatile CFBP 6051T. Similarly, in silico DNA-DNA hybridization (isDDH) value was 74.5% compared to P. versatile CFBP 6051T, isDDH values were 35.5-63.7% with the other Pectobacterium species, which below the 70% threshold value for species delineation (Meier-Kolthoff et al. 2021). The phylogenomic analysis also showed that strain 22TC1 was clustered with the species type strain of P. versatile CFBP 6051T. For pathogenicity tests, cell suspension with ten-fold dilution (approx. 1 x 108 CFU/ml) was injected into the leaf axils of two 2-month-old tobacco stems (cv. Yunyan 87). As a control, tobacco seedlings were inoculated with sterile distilled water. The plants were sealed in plastic bags and maintained in a growth chamber at 28°C for 2 d. The symptoms of water-soaked decay were observed within 24 h of inoculation. Whole-plant decay was at 2 days after injection. No symptoms were developed in the controls. Reisolation was performed on diseased stems and the identity of isolated bacteria was confirmed by PCR and sequencing of 16S rRNA. Similar results were obtained in two independent experiments. Based on the above-described data, the causal pathogen of stem rot on cigar tobacco in Tengchong was identified as P. versatile. To our knowledge, this is the first time that P. versatile is found to cause stem rot on tobacco. Pectobacterium species have been reported to cause seed-borne diseases on tobacco seedlings in the floating tray system and soil-borne diseases in tobacco fields (Wang et al. 2017; Xia and Mo 2007). Therefore, studying the possible transmission of the P. versatile to tobacco plants is necessary.
RESUMO
BACKGROUND: Thrombotic popliteal artery aneurysm (PAA) with acute lower limb ischemia (ALI) is a serious disease leading to amputation. The choice of emergency procedures is not clearly defined, and the difference in therapeutic efficiency between open surgery and endovascular intervention is still unclear. METHOD: We conducted a comprehensive search through PubMed, Wiley Online Library and ScienceDirect. According to the predefined inclusion and exclusion criteria, eligible articles were screened out, and all relevant data were extracted for further analysis. Our study was designed and developed based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Guideline. We critically assessed all included articles by Joanna Briggs Institute (JBI) Critical Appraisal Checklists and the Methodological Index for Non-Randomized Studies (MINORS). RESULT: A total of 29 articles (1338 patients/1387 limbs) were included in the study. After a 1-year follow-up, the primary patency rate of the open surgery group was significantly lower than that of the endovascular intervention group (72.65 vs. 81.46%, P = 0.004), but without significant difference in the secondary patency rate (86.19 vs. 86.86%, P = 0.825). The limb salvage rate of the open surgery group was also significantly lower (83.07 vs. 98.25%, P < 0.001). After the 2-year follow-up, the primary patency rate of the open surgery group was still significantly lower (48.57 vs. 59.90%, P = 0.021). CONCLUSION: The outcome of endovascular intervention was better than that of open surgery especially in the 1-year limb salvage rate and primary patency rate at the 1-year and 2-year follow-ups.
Assuntos
Aneurisma , Procedimentos Endovasculares , Trombose , Humanos , Artéria Poplítea/cirurgia , Isquemia/etiologia , Isquemia/cirurgia , Aneurisma/complicações , Aneurisma/cirurgia , Salvamento de Membro , Trombose/complicações , Trombose/cirurgiaRESUMO
Extremely soft and thin electrodes with high skin conformability have potential applications in wearable devices for personal healthcare. Here, a submicrometer thick, highly robust, and conformable nanonetwork epidermal electrode (NEE) is reported. Electrospinning of polyamide nanofibers and electrospraying of silver nanowires are simultaneously performed to form a homogeneously convoluted network in a nonwoven way. For a 125 nm thick NEE, a low sheet resistance of ≈4 Ω sq-1 with an optical transmittance of ≈82% is achieved. Due to the nanofiber-based scaffold that undertakes most of the stress during deformation, the electric resistance of the NEE shows very little variation; less than 1.2% after 50 000 bending cycles. The NEE can form a fully conformal contact to human skin without additional adhesives, and the NEE shows a contact impedance that is over 50% lower than what is found in commercial gel electrodes. Due to conformal contact even under deformation, the NEE proves to be a stable, robust, and comfortable approach for measuring electrocardiogram signals, especially when a subject is in motion. These features make the NEE promising for use in the ambulatory measurement of physiological signals for healthcare applications.
Assuntos
Nanofibras/química , Nanofios/química , Prata/química , Eletrocardiografia , EletrodosRESUMO
N-acetyl-d-neuraminic acid (Neu5Ac) is a valuable resource that has seen increasing demand in both medicine and biotechnology. Although enzymatic systems and whole-cell biocatalysts have been developed for the synthesis of Neu5Ac, low yield and productivity still hamper the use of these methods on larger scales. We report the creation of an Escherichia coli biocatalyst for the efficient synthesis of Neu5Ac using a metabolic and protein engineering strategy. Expression of the two enzymes, N-acetyl-D-glucosamine 2-epimerase (AGE) and Neu5Ac lyase (NAL), was balanced using promoter engineering. Genes encoding competing pathways and GlcNAc catabolism were deleted, and then a structure-guided process was used to identify a more efficient NAL and an AGE mutant with a higher rate of Neu5Ac synthesis. The resulting biocatalyst produced 351.8â¯mM Neu5Ac with a yield of 58.6% from GlcNAc. This work exemplifies the use of rational design and protein engineering to construct a complex bacterial biocatalyst that can serve as a platform for the large-scale synthesis of a useful biological material.
Assuntos
Biocatálise , Escherichia coli , Microrganismos Geneticamente Modificados , Ácido N-Acetilneuramínico , Escherichia coli/genética , Escherichia coli/metabolismo , Engenharia Metabólica/métodos , Microrganismos Geneticamente Modificados/genética , Microrganismos Geneticamente Modificados/metabolismo , Ácido N-Acetilneuramínico/biossíntese , Ácido N-Acetilneuramínico/genética , Engenharia de Proteínas/métodosRESUMO
Protein phosphatase, Mg(2+)/Mn(2+) dependent, 1D (PPM1D) is emerging as an oncogene by virtue of its negative control on several tumor suppressor pathways. However, the clinical significance of PPM1D in pancreatic cancer (PC) has not been defined. In this study, we determined PPM1D expression in human PC tissues and cell lines and their irrespective noncancerous controls. We subsequently investigated the functional role of PPM1D in the migration, invasion, and apoptosis of MIA PaCa-2 and PANC-1 PC cells in vitro and explored the signaling pathways involved. Furthermore, we examined the role of PPM1D in PC tumorigenesis in vivo. Our results showed that PPM1D is overexpressed in human PC tissues and cell lines and significantly correlated with tumor growth and metastasis. PPM1D promotes PC cell migration and invasion via potentiation of the Wnt/ß-catenin pathway through downregulation of apoptosis-stimulating of p53 protein 2 (ASPP2). In contrast to PPM1D, our results showed that ASPP2 is downregulated in PC tissues. Additionally, PPM1D suppresses PC cell apoptosis via inhibition of the p38 MAPK/p53 pathway through both dephosphorylation of p38 MAPK and downregulation of ASPP2. Furthermore, PPM1D promotes PC tumor growth in vivo. Our results demonstrated that PPM1D is an oncogene in PC.
Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Fosfoproteínas Fosfatases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/química , Apoptose , Carcinogênese/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Regulação para Baixo , Humanos , Invasividade Neoplásica , Fosforilação , Proteína Fosfatase 2C , Via de Sinalização WntRESUMO
BACKGROUND: Regeneration of injured axons in adult mammalian central nervous system (CNS) is not spontaneous. Nogo is a major inhibitory molecule contributing to axon regeneration failure. The molecular mechanisms of Nogo inhibition of axon regeneration are not completely understood. To further investigate the underlying mechanisms, we studied the effects of Nogo-p4, a 25-amino acid core inhibitory fragment of Nogo, on nerve growth factor (NGF)-induced TrkA signaling. METHODS: NGF-differentiated PC12 cells were used as cell models. The effects of Nogo-p4 on two key components of TrkA signaling, phosphorylated Erk1/2 and Akt, were analyzed by western blot. Co-immunoprecipitation experiments were performed to detect the formation of NgR1/p75 complexes. Neurite growth was quantified by measuring the neurite length. RESULTS: Nogo-p4 did not significantly affect TrkA signaling induced by 100 ng/ml NGF, but signaling was suppressed when an NGF concentration of 5 ng/ml was used. Further investigation demonstrated that Nogo-p4 affected TrkA signaling in an NGF concentration-dependent manner. Nogo-p4 suppression of TrkA signaling was strong at low (1 and 5 ng/ml), moderate at intermediate (25 ng/ml), but absent at high (50 and 100 ng/ml) NGF concentrations. NEP1-40 attenuated, and NgR1 overexpression enhanced, Nogo-p4 suppression of TrkA signaling induced by low concentrations of NGF. High but not low concentrations of NGF reduced the formation of NgR1/p75 complexes triggered by Nogo-p4. Nogo-p4 strongly inhibited neurite growth induced by low rather than high concentrations of NGF. CONCLUSION: Nogo-p4 binding with NgR1 suppresses TrkA signaling induced by low concentrations of NGF in differentiated PC12 cells. Suppression of NGF-induced TrkA signaling may be another mechanism by which Nogo inhibits neurite growth.
RESUMO
Bupivacaine is widely used for regional anesthesia, spinal anesthesia, and pain management. However, bupivacaine could cause neuronal injury. Curcumin, a low molecular weight polyphenol, has a variety of bioactivities and may exert neuroprotective effects against damage induced by some stimuli. In the present study, we tested whether curcumin could attenuate bupivacaine-induced neurotoxicity in SH-SY5Y cells. Cell injury was evaluated by examining cell viability, mitochondrial damage and apoptosis. We also investigated the levels of activation of the Akt signaling pathway and the effect of Akt inhibition by triciribine on cell injury following bupivacaine and curcumin treatment. Our findings showed that the bupivacaine treatment could induce neurotoxicity. Pretreatment of the SH-SY5Y cells with curcumin significantly attenuated bupivacaine-induced neurotoxicity. Interestingly, the curcumin treatment increased the levels of Akt phosphorylation. More significantly, the pharmacological inhibition of Akt abolished the cytoprotective effect of curcumin against bupivacaine-induced cell injury. Our data suggest that pretreating SH-SY5Y cells with curcumin provides a protective effect on bupivacaine-induced neuronal injury via activation of the Akt signaling pathway.
Assuntos
Bupivacaína/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Curcumina/farmacologia , Neurônios/efeitos dos fármacos , Síndromes Neurotóxicas/tratamento farmacológico , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Neurônios/metabolismo , Fármacos Neuroprotetores/farmacologia , Síndromes Neurotóxicas/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação/efeitos dos fármacosRESUMO
Currently, development of biofuels as an alternative fuel has gained much attention due to resource and environmental challenges. Bioethanol is one of most important and dominant biofuels, and production using corn or cassava as raw materials has become a prominent technology. However, phytate contained in the raw material not only decreases the efficiency of ethanol production, but also leads to an increase in the discharge of phosphorus, thus impacting on the environment. In this study, to decrease phytate and its phosphorus content in an ethanol fermentation process, Saccharomyces cerevisiae was engineered through a surface-displaying system utilizing the C-terminal half of the yeast α-agglutinin protein. The recombinant yeast strain, PHY, was constructed by successfully displaying phytase on the surface of cells, and enzyme activity reached 6.4 U/g wet biomass weight. Ethanol productions using various strains were compared, and the results demonstrated that the specific growth rate and average fermentation rate of the PHY strain were higher 20 and 18 %, respectively, compared to the control strain S. cerevisiae CICIMY0086, in a 5-L bioreactor process by simultaneous saccharification and fermentation. More importantly, the phytate phosphorus concentration decreased by 89.8 % and free phosphorus concentration increased by 142.9 % in dry vinasse compared to the control in a 5-L bioreactor. In summary, we constructed a recombinant S. cerevisiae strain displaying phytase on the cell surface, which could improve ethanol production performance and effectively reduce the discharge of phosphorus. The strain reported here represents a useful novel engineering platform for developing an environment-friendly system for bioethanol production from a corn substrate.
Assuntos
6-Fitase/metabolismo , Técnicas de Visualização da Superfície Celular/métodos , Enzimas Imobilizadas/metabolismo , Etanol/metabolismo , Engenharia Metabólica/métodos , Ácido Fítico/metabolismo , Saccharomyces cerevisiae/metabolismo , 6-Fitase/genética , Reatores Biológicos , Enzimas Imobilizadas/genética , Fermentação , Manihot/metabolismo , Fósforo/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Zea mays/metabolismoRESUMO
The diploid yeast Candida tropicalis, which can utilize n-alkane as a carbon and energy source, is an attractive strain for both physiological studies and practical applications. However, it presents some characteristics, such as rare codon usage, difficulty in sequential gene disruption, and inefficiency in foreign gene expression, that hamper strain improvement through genetic engineering. In this work, we present a simple and effective method for sequential gene disruption in C. tropicalis based on the use of an auxotrophic mutant host defective in orotidine monophosphate decarboxylase (URA3). The disruption cassette, which consists of a functional yeast URA3 gene flanked by a 0.3 kb gene disruption auxiliary sequence (gda) direct repeat derived from downstream or upstream of the URA3 gene and of homologous arms of the target gene, was constructed and introduced into the yeast genome by integrative transformation. Stable integrants were isolated by selection for Ura+ and identified by PCR and sequencing. The important feature of this construct, which makes it very attractive, is that recombination between the flanking direct gda repeats occurs at a high frequency (10-8) during mitosis. After excision of the URA3 marker, only one copy of the gda sequence remains at the recombinant locus. Thus, the resulting ura3 strain can be used again to disrupt a second allelic gene in a similar manner. In addition to this effective sequential gene disruption method, a codon-optimized green fluorescent protein-encoding gene (GFP) was functionally expressed in C. tropicalis. Thus, we propose a simple and reliable method to improve C. tropicalis by genetic manipulation.
Assuntos
Candida tropicalis/genética , Marcação de Genes/métodos , Genética Microbiana/métodos , Genes Reporter , Proteínas de Fluorescência Verde/genética , Orotidina-5'-Fosfato Descarboxilase/deficiênciaRESUMO
Objective: Bioethanol is a new type of green energy, and predominantly produced currently from starch such as corn and sweet potato. However, pectin contained in the substrates will increase the viscosity of ethanol fermentation broth, which will affect the mass transfer and increase the burden of equipment. In this study, we expressed pectinesterase on the Saccharomyces cerevisiae cell surface and evaluated its effect on fermentation viscosity decrease. Methods: Pectinesterase gene was fused with the C-terminal-half region of α-agglutinin and then inserted into the downstream of the secretion signal gene, to generate a yeast surface-display expression vector pMGK-AG-PE, which was then transformed into the industrial S. cerevisiae. Results: Recombinant yeast strain PE successfully displayed pectinesterase on the surface of cells with 2.6 U/g wet cells. The recombinant enzyme performed the maximal activity at 60 â, pH 5.0, and this enzyme had high activity and stability from pH 4.0 to 5.5. In the simultaneous saccharification and fermentation of sweet potato, the ethanol production of the PE strain was 95 g/L. The viscosity of fermentation broth using the PE strain was lower than that of the parent strain, 120 mPa.s compared to 145 mPa.s after 12 h of fermentation. Conclusion: Expressing pectinesterase on yeast cells surface decreased viscosity of fermentation broth, which is beneficial to starch degradation and ethanol production.
Assuntos
Hidrolases de Éster Carboxílico/metabolismo , Etanol/metabolismo , Proteínas Fúngicas/metabolismo , Ipomoea batatas/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Amido/metabolismo , Aspergillus niger/enzimologia , Biocombustíveis/análise , Hidrolases de Éster Carboxílico/química , Hidrolases de Éster Carboxílico/genética , Estabilidade Enzimática , Fermentação , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Expressão Gênica , Concentração de Íons de Hidrogênio , Ipomoea batatas/química , Ipomoea batatas/microbiologia , Pectinas/metabolismo , TemperaturaRESUMO
Glioblastoma multiforme (GBM) is the most malignant primary brain tumor and more resistant to radiotherapy. However, hetero-radiosensitivity occurs in different patients. MicroRNAs (miRNAs) play important roles in the initiation and progression of a multitude of tumors. The study aims to examine the different microRNAs expression profiles of postoperative radiotherapy sensitive and resistant patients with GBM, to make an inquiry about their potential role and discover a certain set of radio-sensitivity markers. Three paired samples from six GBM patients who had only been treated with postoperative radiotherapy were selected, and then, they were divided into radiotherapy sensitive group and resistant group according to their overall survivals, local recurrence rates, and Karnofsky Performance Scale scores. Expression profiles of miRNAs in these two groups were determined by the method of microarray assay. Comparing with resistant patients, 13 miRNAs were significantly upregulated and 10 miRNAs were greatly downregulated in sensitive group. Among them, four miRNAs were validated by quantitative RT-PCR. The differentially expressed miRNAs and their putative target genes were revealed by bioformatic analysis to play a role in cell signaling, proliferation, aging, and death. High-enrichment pathway analysis identified that some classical pathways participated in numerous metabolic processes, especially in cell cycle regulation, such as mTOR, MAPK, TGF-beta, and PI3K-Akt signaling pathways. Our research will contribute to identifying clinical diagnostic markers and therapeutic targets in the treatment of GBM by postoperative radiotherapy.
Assuntos
Neoplasias Encefálicas/genética , Glioblastoma/genética , MicroRNAs/biossíntese , Tolerância a Radiação/genética , Adulto , Idoso , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/radioterapia , Proliferação de Células/genética , Glioblastoma/radioterapia , Humanos , Masculino , MicroRNAs/genética , Pessoa de Meia-Idade , Período Pós-OperatórioRESUMO
In this study, atmospheric and room temperature plasma (ARTP), a promising mutation breeding technique, was successfully applied to generate Bacillus subtilis mutants that yielded large quantities of recombinant protein. The high throughput screening platform was implemented to select those mutants with the highest yield of recombinant alkaline α-amylase (AMY), including the preferred mutant B. subtilis WB600 mut-12#. The yield and productivity of recombinant AMY in B. subtilis WB600 mut-12# increased 35.0% and 8.8%, respectively, the extracellular protein concentration of which increased 37.9%. B. subtilis WB600 mut-12# exhibited good genetic stability. Cells from B. subtilis WB600 mut-12# became shorter and wider than those from the wild-type. This study is the first to report a novel powerful mutagenesis tool (ARTP) that significantly improves the yield of recombinant proteins in B. subtilis and may therefore play an important role in the high expression level of proteins in recombinant microbial hosts.
Assuntos
Bacillus subtilis/genética , Proteínas Recombinantes/metabolismo , alfa-Amilases/metabolismo , Mutagênese Sítio-Dirigida , Gases em Plasma , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , alfa-Amilases/química , alfa-Amilases/genética , alfa-Amilases/isolamento & purificaçãoRESUMO
We conducted the meta-analysis of all relevant case-control studies aiming to evaluate the relationships of common polymorphisms in forkhead box E1 (FOXE1) and ataxia telangiectasia mutated (ATM) genes to the risk of papillary thyroid carcinoma (PTC). A range of electronic databases were searched without language restrictions: Web of Science (1945 ~ 2013), the Cochrane Library Database (Issue 12, 2013), PubMed (1966 ~ 2013), EMBASE (1980 ~ 2013), CINAHL (1982 ~ 2013), and the Chinese Biomedical Database (CBM) (1982 ~ 2013). This meta-analysis was conducted using the STATA 12.0 software. Crude odds ratio (OR) with their 95 % confidence interval (CI) were calculated. Eight case-control studies with 2,085 PTC patients and 10,341 healthy controls were included. Fourteen common polymorphisms were evaluated, including rs3758249 A > G, rs907577 G > A, rs1867277 G > A, rs3021526 C > T, rs1443434 G > T, rs907580 G > A, rs965513 A > G, rs944289 C > T, and rs189037 G > A polymorphisms in the FOXE1 gene and rs373759 G > A, rs4988099 A > G, rs1801516 G > A, rs664677 T > C, and rs609429 G > C polymorphisms in the ATM gene. Our results demonstrated that the FOXE genetic polymorphisms might be closely related to an increased risk of developing PTC under five genetic models (all P < 0.005), especially for rs3758249, rs907577, rs1867277, rs3021526, rs1443434, rs907580, rs704839, rs894673, and rs10119760 polymorphisms. Nevertheless, no positive associations were found between the ATM genetic polymorphisms and the development of PTC (all P > 0.05). The current meta-analysis provided evidence that FOXE1 genetic polymorphisms may contribute to increased PTC risk, especially for rs3758249, rs907577, rs1867277, rs3021526, rs1443434, rs907580, rs704839, rs894673, and rs10119760 polymorphisms. However, the ATM genetic polymorphisms may not be important dominants of susceptibility to PTC.
Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/genética , Carcinoma/genética , Fatores de Transcrição Forkhead/genética , Estudos de Associação Genética , Neoplasias da Glândula Tireoide/genética , Carcinoma/patologia , Carcinoma Papilar , Estudos de Casos e Controles , Predisposição Genética para Doença , Humanos , Polimorfismo de Nucleotídeo Único , Fatores de Risco , Câncer Papilífero da Tireoide , Neoplasias da Glândula Tireoide/patologiaRESUMO
BACKGROUND: Acute colonic obstruction is the most common complication of colorectal cancer (CRC) in elderly patients. Medical treatment has been associated with higher perioperative morbidity and mortality rates. There is a need for identification of elderly CRC patients who will do poorly so that results can be improved. The purpose of this study is to assess the 30-day outcome of elderly patients undergoing malignant colonic obstruction procedures and identify the associated factors of mortality. METHODS: A review of 233 elderly patients who received medical procedures for malignant colonic obstruction between April 2000 and April 2012 was conducted. Data regarding clinical variables, surgical procedures and outcomes, complications, and mortality were studied. Univariate and logistic regression analyses were performed on mortality risk factors. RESULTS: Patients had a mean age of 78.2 years (range 70-95). A total of 126 (54.1%) patients were classified ASA III and above. Eighty (34.3%) patients had right-sided colonic obstruction. In the 153 (65.7%) patients with left-sided colonic obstruction, 40 patients received self-expandable metallic stent (SEMS) treatment and 193 patients received surgery. A total of 62.2% (n = 145) patients had post operation complications. The overall 30-day mortality was 24.5% (n = 57). ASA grading, peritonitis and Dukes staging were independent risk factors for mortality. CONCLUSIONS: Medical procedures in elderly patients with malignant colonic obstruction are associated with significant complications and mortality. Identifying these high-risk patients and treating promptly may improve outcomes. SEMS treatment provides a useful alternative to surgical intervention.