Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 38
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Appl Environ Microbiol ; 90(2): e0174023, 2024 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-38193674

RESUMO

Pichia pastoris (P. pastoris) is one of the most popular cell factories for expressing exogenous proteins and producing useful chemicals. The alcohol oxidase 1 promoter (PAOX1) is the most commonly used strong promoter in P. pastoris and has the characteristic of biphasic expression. However, the inducer for PAOX1, methanol, has toxicity and poses risks in industrial settings. In the present study, analyzing transcriptomic data of cells collected at different stages of growth found that the formate dehydrogenase (FDH) gene ranked 4960th in relative expression among 5032 genes during the early logarithmic growth phase but rose to the 10th and 1st during the middle and late logarithmic growth phases, respectively, displaying a strict biphasic expression characteristic. The unique transcriptional regulatory profile of the FDH gene prompted us to investigate the properties of its promoter (PFDH800). Under single-copy conditions, when a green fluorescent protein variant was used as the expression target, the PFDH800 achieved 119% and 69% of the activity of the glyceraldehyde-3-phosphate dehydrogenase promoter and PAOX1, respectively. After increasing the copy number of the expression cassette in the strain to approximately four copies, the expression level of GFPuv driven by PFDH800 increased to approximately 2.5 times that of the strain containing GFPuv driven by a single copy of PAOX1. Our PFDH800-based expression system exhibited precise biphasic expression, ease of construction, minimal impact on normal cellular metabolism, and high strength. Therefore, it has the potential to serve as a new expression system to replace the PAOX1 promoter.IMPORTANCEThe alcohol oxidase 1 promoter (PAOX1) expression system has the characteristics of biphasic expression and high expression levels, making it the most widely used promoter in the yeast Pichia pastoris. However, PAOX1 requires methanol induction, which can be toxic and poses a fire hazard in large quantities. Our research has found that the activity of PFDH800 is closely related to the growth state of cells and can achieve biphasic expression without the need for an inducer. Compared to other reported non-methanol-induced biphasic expression systems, the system based on the PFDH800 offers several advantages, including high expression levels, simple construction, minimal impact on cellular metabolism, no need for an inducer, and the ability to fine-tune expression.


Assuntos
Metanol , Pichia , Saccharomycetales , Metanol/metabolismo , Pichia/genética , Pichia/metabolismo , Regulação Fúngica da Expressão Gênica , Regiões Promotoras Genéticas , Proteínas Recombinantes/metabolismo
2.
Biotechnol Bioeng ; 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38978393

RESUMO

ß-Alanine is the only ß-amino acid in nature and one of the most important three-carbon chemicals. This work was aimed to construct a non-inducible ß-alanine producer with enhanced metabolic flux towards ß-alanine biosynthesis in Escherichia coli. First of all, the assembled E. coli endogenous promoters and 5'-untranslated regions (PUTR) were screened to finely regulate the combinatorial expression of genes panDBS and aspBCG for an optimal flux match between two key pathways. Subsequently, additional copies of key genes (panDBS K104S and ppc) were chromosomally introduced into the host A1. On these bases, dynamical regulation of the gene thrA was performed to reduce the carbon flux directed in the competitive pathway. Finally, the ß-alanine titer reached 10.25 g/L by strain A14-R15, 361.7% higher than that of the original strain. Under fed-batch fermentation in a 5-L fermentor, a titer of 57.13 g/L ß-alanine was achieved at 80 h. This is the highest titer of ß-alanine production ever reported using non-inducible engineered E. coli. This metabolic modification strategy for optimal carbon flux distribution developed in this work could also be used for the production of various metabolic products.

3.
World J Microbiol Biotechnol ; 39(2): 42, 2022 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-36513951

RESUMO

Driven by the massive demand in recent years, the production of ß-alanine has significantly progressed in chemical and biological ways. Although the chemical method is relatively mature compared to biological synthesis, its high cost of waste disposal and environmental pollution does not meet the environmental protection standard. Hence, the biological method has become more prevalent as a potential alternative to the chemical synthesis of ß-alanine in recent years. As a result, the aspartate pathway from L-aspartate to ß-alanine (the most significant rate-limiting step in the ß-alanine synthesis) catalyzed by L-aspartate-α-decarboxylase (ADC) has become a research hotspot in recent years. Therefore, it is vital to comprehensively understand the different enzymes that possess a similar catalytic ability to ADC. This review will investigate the exploratory process of unique synthesis features and catalytic properties of ADC/ADC-like enzymes in particular creatures with similar catalytic capacity or high sequence homology. At the same time, we will discuss the different ß-alanine production methods which can apply to future industrialization.


Assuntos
Glutamato Descarboxilase , Isoenzimas , Glutamato Descarboxilase/metabolismo , Ácido Aspártico/metabolismo , beta-Alanina
4.
Bioprocess Biosyst Eng ; 43(10): 1781-1789, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32399751

RESUMO

The major troubles in 6-(N-hydroxyethyl)-amino-6-deoxy-α-L-sorbofuranose (6NSL) production from N-2-hydroxyethyl glucamine (NHEG) by Gluconobacter oxydans were low cell yield during cell preparation and loss of cells' biocatalytic ability during biotransformation, resulting in high production cost and low 6NSL production. The target of this work was to enhance 6NSL production by reusing cells and improving the cells biocatalytic ability. First, inhibitory effects of substrate and product on 6NSL production, and optimization of cell regeneration condition were investigated, respectively. Then repeated production of 6NSL by immobilized cell using a strategy of in situ exhaustive cell regeneration in a bubble column bioreactor was developed. As a result, the bioprocess underwent nine cycles, the average 6NSL production and conversion rate of NHEG to 6NSL reached 42.6 g L-1 and 83.1% in each batch was achieved, respectively.


Assuntos
Reatores Biológicos , Células Imobilizadas/metabolismo , Gluconobacter oxydans/metabolismo , Sorbose , Sorbose/análogos & derivados , Sorbose/biossíntese
5.
Bioprocess Biosyst Eng ; 43(11): 2009-2015, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32557175

RESUMO

Echinocandin B (ECB) is a key precursor of antifungal agent Anidulafungin, which has demonstrated clinical efficacy in patients with invasive candidiasis. In this study, the effects of microparticle-enhanced cultivation and methyl oleate on echinocandin B fermentation titer were investigated. The results showed that the titer was significantly influenced by the morphological type of mycelium, and mycelium pellet was beneficial to improve the titer of this secondary metabolism. First, different carbon sources were chosen for the fermentation, and methyl oleate achieved the highest echinocandin B titer of 2133 ± 50 mg/L, which was two times higher than that of the mannitol. The study further investigated the metabolic process of the fermentation, and the results showed that L-threonine concentration inside the cell could reach 275 mg/L at 168 h with methyl oleate, about 2.5 times higher than that of the mannitol. Therefore, L-threonine may be a key precursor of echinocandin B. In the end, a new method of adding microparticles for improving the mycelial morphology was used, and the addition of talcum powder (20 g/L, diameter of 45 µm) could make the maximum titer of echinocandin B reach 3148 ± 100 mg/L.


Assuntos
Equinocandinas/química , Fermentação/efeitos dos fármacos , Proteínas Fúngicas/química , Manitol/química , Ácidos Oleicos/química , Treonina/química , Aspergillus nidulans , Candidíase/tratamento farmacológico , Carbono/química , Meios de Cultura , Microesferas , Micélio/metabolismo , Talco/química , Viscosidade
7.
Prep Biochem Biotechnol ; 50(8): 745-752, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32125248

RESUMO

Echinocandin B, a kind of antimycotic with cyclic lipo-hexapeptides, was produced by fermentation with Aspergillus nidulans using fructose as main carbon source. The objective of this study was to screen a high-yield mutant capable of using cheap starch as main carbon source by atmospheric and room temperature plasma (ARTP) treatment in order to decrease the production cost of echinocandin B. A stable mutant A. nidulans ZJB19033, which can use starch as optimal carbon source instead of expensive fructose, was selected from two thousands isolates after several cycles of ARTP mutagenesis. To further increase the production of echinocandin B, the optimization of fermentation medium was performed by response surface methodology (RSM), employing Plackett-Burman design (PBD) followed by Box-Behnken design (BBD). The optimized fermentation medium provided the optimal yield of echinocandin B, 2425.9 ± 43.8 mg/L, 1.3-fold compared to unoptimized medium. The results indicated that the mutant could achieve high echinocandin B production using cheap starch as main carbon source, and the cost of carbon sources in fermentation medium reduced dramatically by about 45%.


Assuntos
Aspergillus nidulans/genética , Equinocandinas/genética , Proteínas Fúngicas/genética , Mutagênese , Amido/metabolismo , Aspergillus nidulans/metabolismo , Meios de Cultura/metabolismo , Equinocandinas/metabolismo , Fermentação , Proteínas Fúngicas/metabolismo , Microbiologia Industrial/métodos
8.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 49(1): 136-139, 2018 Jan.
Artigo em Zh | MEDLINE | ID: mdl-29737105

RESUMO

OBJECTIVE: To analyze the clinical characteristics of infective endocarditis (IE) in culture-positive patients,so as to provide the evidences for reasonable diagnosis and treatment of IE. METHODS: We performed a retrospective study of 157 culture-positive IE cases,which were diagnosed according to modified Duke criteria for IE from Jan. 2008 to Aug. 2015. RESULTS: The average age of 157 cases of IE was 40.85 years. One hundred and one patients (64.3%) had various underlying cardiac diseases,including congenital cardiovascular diseases in 44 cases and rheumatic heart diseases in 15 cases. The main clinical manifestations were anemia (147 cases,93.6%),fever(137 cases,87.3%) and heart murmur (120 cases,76.4%). Vegetation was found in 12 cases (7.6%) with transesophageal echocardiography (TEE) but not with transthoracic echocardiography (TTE) . Culture results showed the most common causative microorganisms were Streptococci (76 cases,48.4%),with Viridans streptococci dominated in 70 cases,and Staphylococci (33 cases,21.0%) (Staphylococcus aureus dominated in 18 cases). All patients were treated with antimicrobial agents. Eighty-five patients (54.1%) received surgical intervention,of which 72 cases received valve replacement. Twenty-seven patients were cured,88 patients were markedly improved,38 patients discontinued treatment,and 4 patients died. The therapeutic efficacy of operation group was better. CONCLUSION: The clinical characteristics of IE included: the age of onset increased,congenital heart disease was the most underlying disease,and Viridians streptococci was the most popular causative microorganism. Surgical therapy can effectively improve the outcomes of IE patients.


Assuntos
Endocardite Bacteriana/epidemiologia , Infecções Estafilocócicas/epidemiologia , Infecções Estreptocócicas/epidemiologia , Adulto , Idade de Início , Endocardite Bacteriana/tratamento farmacológico , Endocardite Bacteriana/cirurgia , Cardiopatias Congênitas/complicações , Humanos , Estudos Retrospectivos , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus , Infecções Estreptocócicas/tratamento farmacológico , Estreptococos Viridans
9.
Biotechnol Appl Biochem ; 64(3): 392-399, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-27098203

RESUMO

An effective epoxide hydrolase (EH) production strain was mutagenized using 60 Co gamma and UV irradiation. Among positive mutant strains, the EH activity of C2-44 reached 33.7 U/g, which was 267% as much as that of the original Aspergillus niger ZJB-09103. Compared with the wild type, there were significant changes in morphology for C2-44, including the color of mycelia on the slants and the shape of conidial head. In addition, glucose and soybean cake were the optimal carbon and nitrogen source in terms of EH activity for the mutant C2-44 instead of soluble starch and peptone for the wild-type strain. The reaction time required to reach 99% enantiomeric excesses of (S)-epichlorohydrin from racemic substrate was shortened significantly by the mutant C2-44. This phenomenon was probably explained by the higher Vmax for hydrolysis of racemic epichlorohydrin by C2-44 compared with Aspergillus niger ZJB-09103.


Assuntos
Aspergillus niger , Epóxido Hidrolases , Proteínas Fúngicas , Raios gama , Mutagênese/efeitos da radiação , Raios Ultravioleta , Aspergillus niger/enzimologia , Aspergillus niger/genética , Epóxido Hidrolases/biossíntese , Epóxido Hidrolases/genética , Proteínas Fúngicas/biossíntese , Proteínas Fúngicas/genética
10.
Artigo em Zh | MEDLINE | ID: mdl-30124241

RESUMO

Objective: To analyze the clinical features of neurocysticercosis(NCC) to provide evidence for clinical diagnosis and treatment of the disease. Methods: Medical records of NCC patients in the West China Hospital of Sichuan University received between January 2003 and January 2013 were reviewed retrospectively. The epidemiological data, clinical manifestations, therapeutic procedures and outcomes of the patients were analyzed. Results: A total of 94 NCC patients met the recruiting criteria, of whom 67.0%(63/94) were male, 59.6%(56/94) ranged 30-55 years old, 73.4%(69/94) had a living history in endemic regions such as Aba, Ganzi and Liangshan prefectures, 80.9%(76/94) lived in rural areas. NCC was clinically characterized by epilepsy, headache and intracranial hypertension. The positive rate for anti-T. solium antibodies by ELISA was 96.8%(91/94), and the total positive scan rate of neuroimaging including CT and MRI was 95.7%(90/94). In addition, 73 patients were suspected to have NCC at the first diagnosis, with a misdiagnosis rate of 22.3%(21/94). Seventy-nine of the patients received albendazole treatmentï¼»20 mg/(kg·d), twice per day for 10 days as one treatment course, 1-3 courses as neededï¼½. Eleven patients received praziquantel(total dose of 120-180 mg/kg, 3 times per day for 3 days as one treatment course, 1-3 courses), and 4 received a combination of albendazole and praziquantel. Symptoms improved in 77 cases(81.9%), but 12 of them(12/77, 15.6%) relapsed. The improvement rate of the albendazole group(6/11, 84.8%) was significantly higher than that of the praziquantel group(54.6%)(P<0.05). Conclusion: NCC more commonly occurs in young males and lacks specific clinical manifestations. Neuroimaging combined with serum specific antibody tests is crucial for diagnosis. Albendazole has better therapeutic effects than praziquantel.


Assuntos
Neurocisticercose , Adulto , Albendazol , Anticorpos , China , Erros de Diagnóstico , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Praziquantel , Estudos Retrospectivos
11.
Appl Biochem Biotechnol ; 196(3): 1450-1463, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37418127

RESUMO

S-adenosyl-l-methionine (SAM), a vital physiologically active substance in living organisms, is produced by fermentation over Saccharomyces cerevisiae. The main limitation in SAM production was the low biosynthesis ability of SAM in S. cerevisiae. The aim of this work is to breed an SAM-overproducing mutant through UV mutagenesis coupled with high-throughput selection. Firstly, a high-throughput screening method by rapid identification of positive colonies was conducted. White colonies on YND medium were selected as positive strains. Then, nystatin/sinefungin was chosen as a resistant agent in directed mutagenesis. After several cycles of mutagenesis, a stable mutant 616-19-5 was successfully obtained and exhibited higher SAM production (0.41 g/L vs 1.39 g/L). Furthermore, the transcript levels of the genes SAM2, ADO1, and CHO2 involved in SAM biosynthesis increased, while ergosterol biosynthesis genes in mutant 616-19-5 significantly decreased. Finally, building on the above work, S. cerevisiae 616-19-5 could produce 10.92 ± 0.2 g/L SAM in a 5-L fermenter after 96 h of fermentation, showing a 2.02-fold increase in the product yield compared with the parent strain. Paving the way of breeding SAM-overproducing strain has improved the good basis for SAM industrial production.


Assuntos
Metionina , S-Adenosilmetionina , Saccharomyces cerevisiae/genética , Ensaios de Triagem em Larga Escala , Melhoramento Vegetal , Racemetionina
12.
Biotechnol Lett ; 35(6): 937-42, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23430130

RESUMO

Biotransformation of 1,3-dichloro-2-propanol (DCP) to epichlorohydrin (ECH) by the whole cells of recombinant Escherichia coli expressing halohydrin dehalogenase was limited by product inhibition. To solve this problem and improve the ECH yield, a biotransformation strategy using resin-based in situ product removal (ISPR) was investigated. Seven macroporous resins were examined to adsorb ECH: resin HZD-9 was the best. When 10 % (w/v) HZD-9 was added to batch biotransformation, 53.3 mM ECH was obtained with a molar yield of 88.3 %. The supplement of the HZD-9 increased the ECH volumetric productivity from 0.5 to 2.8 mmol/l min compared to without addition of resin. In fed-batch biotransformation, this approach increased ECH from 31 to 87 mM. These results provide a promising basis for the biosynthesis of ECH.


Assuntos
Biotecnologia/métodos , Epicloroidrina/isolamento & purificação , Epicloroidrina/metabolismo , Escherichia coli/metabolismo , Hidrolases/metabolismo , alfa-Cloridrina/análogos & derivados , Adsorção , Biotransformação , Inibidores Enzimáticos/isolamento & purificação , Inibidores Enzimáticos/metabolismo , Escherichia coli/enzimologia , Escherichia coli/genética , Hidrolases/genética , Polímeros/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , alfa-Cloridrina/metabolismo
13.
Artigo em Zh | MEDLINE | ID: mdl-24809196

RESUMO

OBJECTIVE: To analyze the clinical and epidemiological characteristics of visceral leishmaniasis cases in Sichuan. METHODS: The medical records of 137 patients with visceral leishmaniasis were reviewed between January 2000 and April 2012 in West China Hospital. The epidemiological data, clinical manifestations, laboratory features, diagnosis, therapeutic procedures and outcome of the patients were retrospectively analyzed. RESULTS: Eighty-eight (64.2%) out of 137 cases were the residents in the endemic area of Sichuan Province and adjacent areas, and 49 (35.8%) were non-endemic area residents with a history of visiting endemic area. Patients living in rural areas accounted for 84.7% (116/137), in town for 15.3% (21/137). Visceral leishmaniasis should be strongly suspected in a patient with prolonged fever, marked hepatosplenomegaly, lymphadenectasis, cytopenia and hypergammaglobulinemia. All patients showed positive in rk39 dipstick test, and were treated with antimony sodium gluconate. Among these patients, 86.1% (118/137) were cured by drug, 2.9% (4/137) received splenectomy, and 6.6% (9/137) relapsed. The misdiagnosis rate was 23.4% (32/137). CONCLUSION: Bone marrow smear staining and biopsy, combined with rk39 antibody detection and epidemiological history are crucial for early diagnosis and treatment of visceral leishmaniasis. Antimonials is still an effective therapeutic choice.


Assuntos
Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/epidemiologia , Adolescente , Adulto , Criança , Pré-Escolar , China/epidemiologia , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
14.
Front Genet ; 14: 1180500, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37265963

RESUMO

Objectives: This study aimed to explore cell type level expression quantitative trait loci (eQTL) in adenocarcinoma at the gastroesophageal junction (ACGEJ) and identify susceptibility and prognosis markers. Methods: Whole-genome sequencing (WGS) was performed on 120 paired samples from Chinese ACGEJ patients. Germline mutations were detected by GATK tools. RNA sequencing (RNA-seq) data on ACGEJ samples were taken from our previous studies. Public single-cell RNA sequencing (scRNA-seq) data were used to produce the proportion of epithelial cells. Matrix eQTL and a linear mixed model were used to identify condition-specific cis-eQTLs. The R package coloc was used to perform co-localization analysis with the public data of genome-wide association studies (GWASs). Log-rank and Cox regression tests were used to identify survival-associated eQTL and genes. Functions of candidate risk loci were explored by experimental validation. Results: Refined eQTL analyses of paired ACGEJ samples were performed and 2,036 potential ACGEJ-specific eQTLs with East Asian specificity were identified in total. ACGEJ-gain eQTLs were enriched at promoter regions more than ACGEJ-loss eQTLs. rs658524 was identified as the top eQTL close to the transcription start site of its paired gene (CTSW). rs2240191-RASAL1, rs4236599-FOXP2, rs4947311-PSORS1C1, rs13134812-LOC391674, and rs17508585-CDK13-DT were identified as ACGEJ-specific susceptibility eQTLs. rs309483-LINC01355 was associated with the overall survival of ACGEJ patients. We explored functions of candidate eQTLs such as rs658524, rs309483, rs2240191, and rs4947311 by experimental validation. Conclusion: This study provides new risk loci for ACGEJ susceptibility and effective disease prognosis biomarkers.

15.
Cancer Cell ; 41(12): 2038-2050.e5, 2023 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-38039962

RESUMO

Esophageal squamous cell carcinoma (ESCC) develops through a series of increasingly abnormal precancerous lesions. Previous studies have revealed the striking differences between normal esophageal epithelium and ESCC in copy number alterations (CNAs) and mutations in genes driving clonal expansion. However, due to limited data on early precancerous lesions, the timing of these transitions and which among them are prerequisites for malignant transformation remained unclear. Here, we analyze 1,275 micro-biopsies from normal esophagus, early and late precancerous lesions, and esophageal cancers to decipher the genomic alterations at each stage. We show that the frequency of TP53 biallelic inactivation increases dramatically in early precancerous lesion stage while CNAs and APOBEC mutagenesis substantially increase at late stages. TP53 biallelic loss is the prerequisite for the development of CNAs of genes in cell cycle, DNA repair, and apoptosis pathways, suggesting it might be one of the earliest steps initiating malignant transformation.


Assuntos
Carcinoma de Células Escamosas , Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Lesões Pré-Cancerosas , Humanos , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/patologia , Carcinoma de Células Escamosas do Esôfago/genética , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Genômica , Lesões Pré-Cancerosas/genética , Lesões Pré-Cancerosas/patologia
16.
Int J Biol Sci ; 19(8): 2551-2571, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37215984

RESUMO

The apolipoprotein B mRNA editing enzyme catalytic polypeptide (APOBEC) mutagenesis is prevalent in esophageal squamous cell carcinoma (ESCC). However, the functional role of APOBEC mutagenesis has yet to be fully delineated. To address this, we collect matched multi-omics data of 169 ESCC patients and evaluate characteristics of immune infiltration using multiple bioinformatic approaches based on bulk and single-cell RNA sequencing (scRNA-seq) data and verified by functional assays. We find that APOBEC mutagenesis prolongs overall survival (OS) of ESCC patients. The reason for this outcome is probably due to high anti-tumor immune infiltration, immune checkpoints expression and immune related pathway enrichment, such as interferon (IFN) signaling, innate and adaptive immune system. The elevated AOBEC3A (A3A) activity paramountly contributes to the footprints of APOBEC mutagenesis and is first discovered to be transactivated by FOSL1. Mechanistically, upregulated A3A exacerbates cytosolic double-stranded DNA (dsDNA) accumulation, thus stimulating cGAS-STING pathway. Simultaneously, A3A is associated with immunotherapy response which is predicted by TIDE algorithm, validated in a clinical cohort and further confirmed in mouse models. These findings systematically elucidate the clinical relevance, immunological characteristics, prognostic value for immunotherapy and underlying mechanisms of APOBEC mutagenesis in ESCC, which demonstrate great potential in clinical utility to facilitate clinical decisions.


Assuntos
Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Animais , Camundongos , Carcinoma de Células Escamosas do Esôfago/genética , Carcinoma de Células Escamosas do Esôfago/terapia , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/terapia , Mutagênese , Imunoterapia
17.
Cell Rep ; 42(10): 113270, 2023 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-37851572

RESUMO

Esophageal squamous-cell carcinoma (ESCC) is commonly treated with radiotherapy; however, radioresistance hinders its clinical effectiveness, and the underlying mechanism remains elusive. Here, we develop patient-derived xenografts (PDXs) from 19 patients with ESCC to investigate the mechanisms driving radioresistance. Using RNA sequencing, cytokine arrays, and single-cell RNA sequencing, we reveal an enrichment of cancer-associated fibroblast (CAF)-derived collagen type 1 (Col1) and tumor-cell-derived CXCL1 in non-responsive PDXs. Col1 not only promotes radioresistance by augmenting DNA repair capacity but also induces CXCL1 secretion in tumor cells. Additionally, CXCL1 further activates CAFs via the CXCR2-STAT3 pathway, establishing a positive feedback loop. Directly interfering with tumor-cell-derived CXCL1 or inhibiting the CXCL1-CXCR2 pathway effectively restores the radiosensitivity of radioresistant xenografts in vivo. Collectively, our study provides a comprehensive understanding of the molecular mechanisms underlying radioresistance and identifies potential targets to improve the efficacy of radiotherapy for ESCC.


Assuntos
Fibroblastos Associados a Câncer , Carcinoma de Células Escamosas , Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Tolerância a Radiação , Humanos , Fibroblastos Associados a Câncer/metabolismo , Fibroblastos Associados a Câncer/efeitos da radiação , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/radioterapia , Carcinoma de Células Escamosas/metabolismo , Linhagem Celular Tumoral , Quimiocina CXCL1/metabolismo , Colágeno/metabolismo , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/radioterapia , Neoplasias Esofágicas/metabolismo , Carcinoma de Células Escamosas do Esôfago/radioterapia , Carcinoma de Células Escamosas do Esôfago/genética , Carcinoma de Células Escamosas do Esôfago/metabolismo
18.
Enzyme Microb Technol ; 164: 110189, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36586225

RESUMO

S-adenosyl-L-methionine (SAM), used in diverse pharmaceutical applications, was biosynthesized from L-methionine (L-met) and adenosine triphosphate (ATP). This study aims to increase the accumulation of SAM in Saccharomyces cerevisiae by promoting ATP availability. Strain ΔSOD1 was obtained from the parent strain WT15-33 (CCTCC M 2021915) by deleting gene sod1, which improved the supply of ATP. The SAM content in strain ΔSOD1 exhibited a 22.3% improvement compared to the parent strain, which reached 93.6 mg g-1. The transformation of NADH (reduced nicotinamide adenine dinucleotide) and the relative expression of ATPase essential genes were investigated, respectively. The results showed that the lack of gene sod1 benefited the generation of ATP, which positively regulated the synthesis of SAM. Besides that, the production of SAM was further enhanced by improving substrate assimilation. With the infusion of 1.44 g L-1L-met and 0.60 g L-1 adenosine at 24 h (h) and 0 h following fermentation, the optimum medium could produce 1.54 g L-1 SAM. Based on the regulations mentioned above, the SAM concentration of strain ΔSOD1 enhanced from 7.3 g L-1 to 10.1 g L-1 in a 5-L fermenter in 118 h. This work introduces a novel idea for the biosynthesis of ATP and SAM, and the strain ΔSOD1 has the potential for industrial production.


Assuntos
S-Adenosilmetionina , Saccharomyces cerevisiae , Trifosfato de Adenosina/metabolismo , Fermentação , Metionina/metabolismo , S-Adenosilmetionina/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Superóxido Dismutase-1
19.
Biotechnol Appl Biochem ; 59(3): 170-7, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23586826

RESUMO

In the current study, the haloalcohol dehalogenase HheC gene from Agrobacterium radiobacter AD1 was synthesized and expressed in Escherichia coli. After purification using Ni-nitrilotriacetic acid affinity chromatography, HheC was used in the synthesis of chiral epichlorohydrin in the presence of NO2⁻. The optimal pH, temperature, and NO2⁻ concentration for enantioselectivity are 5.0, 37°C, and 60 mM, respectively. The maximum velocity and Michaelis constant values for (S)-epichlorohydrin are 714.3 µmol min⁻¹ mg⁻¹ and 17.2 mM, respectively, whereas those for (R)-epichlorohydrin are 166.8 µmol min⁻¹ mg⁻¹ and 29.0 mM, respectively. Under optimal conditions, (R)-epichlorohydrin with 99% enantiomeric excess was obtained after an 18 Min reaction; the yield reached 41%, which is the highest amount obtained for chiral epichlorohydrin synthesis using haloalcohol dehalogenase. In addition, (R)-epichlorohydrin with 99% enantiomeric excess was successfully obtained from 1,3-dichloro-2-propanol by the ring opening of racemic epichlorohydrin in the presence of NO2⁻ after the ring closure of 1,3-dichloro-2-propanol with HheC. To the best of our knowledge, the current study is the first report on the kinetic resolution of epichlorohydrin with NO2⁻ and synthesis of chiral epichlorohydrin with 99% enantiomeric excess from 1,3-dichloro-2-propanol by combining ring closure of 1,3-dichloro-2-propanol and ring opening of racemic epichlorohydrin.


Assuntos
Agrobacterium tumefaciens/enzimologia , Epicloroidrina/síntese química , Hidrolases/metabolismo , Microbiologia Industrial/métodos , Nitritos/metabolismo , Clonagem Molecular , Eletroforese em Gel de Poliacrilamida , Escherichia coli/genética , Concentração de Íons de Hidrogênio , Estrutura Molecular , Estereoisomerismo , Temperatura
20.
Bioprocess Biosyst Eng ; 35(5): 751-60, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22116528

RESUMO

The lignin-modifying enzymes (LMEs) play an important role in decomposition of agricultural residues, which contain a certain amount of lignin. In this study, the production of LMEs by three co-cultivated combinations of Phlebia radiata, Dichomitus squalens and Ceriporiopsis subvermispora and the respective monocultures was comparatively investigated. Laccase and manganese peroxidases (MnP) were significantly promoted in the co-culture of P. radiata and D. squalens, and corncob was verified to be beneficial for laccase and MnP production. Moreover, laccase production by co-culture of P. radiata and D. squalens with high ratio of glucose to nitrogen was higher than low ratio under carbon- and nitrogen-meager conditions. New laccase isoenzymes measured by Native-PAGE were stimulated by co-cultured P. radiata with D. squalens or C. subvermispora, respectively, growing in the defined medium containing corncob, but the expression of laccase was greatly restrained by the co-culturing of D. squalens with C. subvermispora. This study showed that the synergistic and depressing effects of co-cultivation of P. radiata, D. squalens and C. subvermispora on LMEs were species specific.


Assuntos
Coriolaceae/enzimologia , Coriolaceae/crescimento & desenvolvimento , Proteínas Fúngicas/biossíntese , Lacase/biossíntese , Peroxidases/biossíntese , Técnicas de Cocultura , Lignina/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA