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2.
Orthop Surg ; 2021 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-34939333

RESUMO

This study was designed to analyze the causes of cervical adjacent segment degenerative disease (ASDis), evaluate the surgical outcomes of longitudinal spinous-splitting laminoplasty with coral bone (SLAC) during cervical reoperation, and accumulate data on reoperation with SLAC in a primary hospital. Based on the inclusion and exclusion criteria, we conducted a retrospective study involving 52 patients who underwent cervical reoperation for ASDis using SLAC at the spinal surgery department of the Beijing Jishuitan Hospital from 1998 to 2014. Among them, 39 were treated with anterior cervical fusion and internal fixation during the first operation (anterior cervical corpectomy with fusion [ACCF], n = 24; anterior cervical discectomy and fusion [ACDF], n = 11; and cervical disc arthroplasty [CDA], n = 4). Outcomes were the Japanese Orthopaedic Association (JOA) score, neck disability index (NDI) score, upper limb/neck and shoulder evaluated using a visual analogue scale (VAS), and rates of ASDis. In patients who underwent an anterior cervical approach in the first instance, the incidence of ASDis was significantly higher in the C3/4 gap than in the other gaps. In the ACCF group, the lateral radiograph of the cervical spine revealed that the distance between the anterior cervical plate and the adjacent segment disc was <5 mm in 15 (62.5%) cases and five (12.8%) cases, respectively, the internal fixation screws broke into the annulus of the adjacent segment. After the first SLAC, ASDis developed at C2/3 and C3/4 in four (30.8%) and eight (61.5%) cases, respectively. After reoperation, all cases were followed up for >5 (average, 6.2) years. The pre-reoperation and last follow-up values were as follows: mean Japanese Orthopaedic Association score, 10.2 ± 1.5 vs 15.5 ± 0.7 (P = 0.03); neck disability index, 26.2 vs 13.6 points (P = 0.01); upper-limb visual analog scale (VAS) score, 6.1 vs 2.6 points (P = 0.04); and neck and shoulder VAS score, 6.6 vs 2.1 points (P = 0.03). SLAC is a simple technique in which the local anatomy is clearly visible and satisfactory clinical outcomes are obtained.

3.
Front Oncol ; 11: 780601, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34926294

RESUMO

Cholangiocarcinoma (CCA) is featured by common occurrence and poor prognosis. Autophagy is a biological process that has been extensively involved in the progression of tumors. Long noncoding RNAs (lncRNAs) have been discovered to be critical in diagnosing and predicting various tumors. It may be valuable to elaborate autophagy-related lncRNAs (ARlncRNAs) in CCA, and indeed, there are still few studies concerning the role of ARlncRNAs in CCA. Here, a prognostic ARlncRNA signature was constructed to predict the survival outcome of CCA patients. Through identification, three differentially expressed ARlncRNAs (DEARlncRNAs), including CHRM3.AS2, MIR205HG, and LINC00661, were screened and were considered predictive signatures. Furthermore, the overall survival (OS) of patients with high-risk scores was significantly lower than that of patients with low scores. Interestingly, the risk score was an independent factor for the OS of patients with CCA. Moreover, receiver operating characteristic (ROC) curve analysis showed that the screened and constructed prognosis signature for 1 year (AUC = 0.884), 3 years (AUC =0.759), and 5 years (AUC = 0.788) presented a high score of accuracy in predicting OS of CCA patients. Gene set enrichment analysis (GSEA) revealed that the three DEARlncRNAs were significantly enriched in CCA-related signaling pathways, including "pathways of basal cell carcinoma", "glycerolipid metabolism", etc. Quantitative real-time PCR (qRT-PCR) showed that expressions of CHRM3.AS2, MIR205HG, and LINC00661 were higher in CCA tissues than those in normal tissues, similar to the trends detected in the CCA dataset. Furthermore, Pearson's analysis reported an intimate correlation of the risk score with immune cell infiltration, indicating a predictive value of the signature for the efficacy of immunotherapy. In addition, the screened lncRNAs were found to have the ability to modulate the expression of mRNAs by interacting with miRNAs based on the established lncRNA-miRNA-mRNA network. In conclusion, our study develops a novel nomogram with good reliability and accuracy to predict the OS of CCA patients, providing a significant guiding value for developing tailored therapy for CCA patients.

4.
FASEB J ; 35(12): e22005, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34788479

RESUMO

Preeclampsia is a significant contributor for maternal or fetal morbidity and mortality, which is characterized by reduced invasion capacity of trophoblasts and is regulated by extracellular matrix (ECM). It is still under investigation whether chorionic villus-derived mesenchymal stem cells (CVMSC) could affect the functionality of trophoblasts. In this study, CVMSC-derived exosomes were isolated; their effect on trophoblasts was investigated based on the CCK8 assay, migration assay, and apoptosis detection. And the underlying mechanism of this effect was investigated using mRNA sequencing, western blot, co-immunoprecipitation, luciferase report assay, and ubiquitination assay. The results show that CVMSC-derived exosomes promote migration and proliferation of trophoblasts, and also reduce cell apoptosis. mRNA sequencing confirmed that after treatment of CVMSC-derived exosomes, Tripartite Motif Containing 72 (TRIM72) expression was upregulated and Tumor Protein P53 (P53) expression was downregulated, both significantly in trophoblasts. Subsequent study confirms that TRM72 can directly interact with P53 and promote P53 ubiquitination and proteasomal degradation, reducing apoptosis rate and elevating proliferation and migration in trophoblasts. Our study confirms that CVMSC-derived exosomes promote trophoblast migration and proliferation by upregulating TRIM72 expression, and subsequently advance P53 ubiquitination and proteasomal degradation.

5.
Transl Vis Sci Technol ; 10(13): 30, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34817575

RESUMO

Purpose: To investigate the effects of indocyanine green (ICG) solution on the viability and cytolysis of human lens epithelial cells ex vivo. Methods: A total of 200 pieces of anterior capsules were obtained during cataract surgery, and 110 pieces of the anterior capsules were randomly divided into five groups and treated by immersion in different concentrations of ICG solution. The remaining 90 anterior capsules were also divided into five groups and treated with a combination of drug immersion and washing in balanced salt solution. Electron microscopy and trypan blue and eosin stains were used to analyze the cells. Percentage of dead, shedding, or living lens epithelial cells was estimated and used to demonstrate effects of the ICG on viability and cytolysis. Results: Compared with the control group, the percentage of dead and shedding lens epithelial cells increased while the percentage of living lens epithelial cells decreased in all the immersion groups. In the washing groups, the percentage of the living lens epithelial cells was 63.42% ± 2.49%, 54.04% ± 1.84%, 43.51% ± 2.63%, 29.21% ± 2.40%, and 15.73% ± 1.61% for the five groups and reflected a concentration-effect relationship. Electron microscopy showed that the higher the concentration of the ICG solution, the more severe the destruction of the lens epithelial cell structure. Conclusions: ICG could reduce the viability of the lens epithelial cells and promote cell cytolysis. Translational Relevance: Our study showed that ICG could directly reduce the viability of the lens epithelial cells in a concentration-dependent fashion, which can theoretically reduce the incidence of posterior capsule opacification.

6.
Zhongguo Dang Dai Er Ke Za Zhi ; 23(11): 1132-1140, 2021 Nov 15.
Artigo em Inglês, Chinês | MEDLINE | ID: mdl-34753545

RESUMO

OBJECTIVES: To study the association of ß2-drenergic receptor (ADRB2) regulatory region single nucleotides polymorphism (SNP)/haplotypes at rs11168070, rs17108803, rs2053044, rs12654778, rs11959427, and rs2895795 loci with childhood asthma. METHODS: A total of 143 children with asthma who attended the hospital from October 2016 to October 2020 were enrolled as the asthma group, among whom 61 children had mild symptoms (mild group) and 82 children had moderate-to-severe symptoms (moderate-to-severe group). A total of 137 healthy children were enrolled as the control group. Peripheral venous blood samples were collected from the two groups. The SNaPshot SNP technique was used to analyze the SNP and haplotypes of the ADRB2 regulatory region at rs11168070, rs17108803, rs2053044, rs12654778, rs11959427, and rs2895795 loci in all children. The asthma group and the control group were compared in terms of the association of ADRB2 regulatory region SNP and haplotypes at the above six loci with susceptibility to asthma and severity of asthma. RESULTS: Polymorphisms were observed in the ADRB2 regulation region at the above six loci in both the asthma group and the control group, with significant differences between the two groups in the distribution of genotype and allele frequencies at rs2895795 (-1429T /A), rs2053044(-1023G/A), and rs12654778 (-654G/A) loci (P<0.05). Linkage disequilibrium of SNP was observed at the six loci of the ADRB2 regulatory region.The haplotypes of TATGCT, TATGGC, and AGTGCT were associated with susceptibility to childhood asthma, among which TATGCT and TATGGC were risk factors for childhood asthma (OR=1.792 and 1.946 respectively, P<0.05), while AGTGCT was a protective factor (OR=0.523, P<0.05). CONCLUSIONS: SNP/haplotype of the ADRB2 regulatory region is associated with the susceptibility to childhood asthma. The haplotypes of TATGCT and TATGGC formed by such SNP/haplotype are risk factors for childhood asthma, while AGTGCT is a protective factor.


Assuntos
Asma , Receptores Adrenérgicos beta 2 , Asma/genética , Estudos de Casos e Controles , Criança , Predisposição Genética para Doença , Genótipo , Haplótipos , Humanos , Polimorfismo de Nucleotídeo Único , Receptores Adrenérgicos beta 2/genética , Sequências Reguladoras de Ácido Nucleico
7.
J Phys Chem B ; 125(37): 10452-10458, 2021 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-34520210

RESUMO

Bioluminescence of a number of marine organisms is conditioned by Ca2+-regulated photoprotein (CaRP) with coelenterazine as the reaction substrate. The reaction product, coelenteramide, at the first singlet excited state (S1) is the emitter of CaRP. The S1-state coelenteramide is produced via the decomposition of coelenterazine dioxetanone. Experiments suggested that the neutral S1-coelenteramide is the primary emitter species. This supposition contradicts with theoretical calculations showing that the anionic S1-coelenteramide is a primary product of the decomposition of coelenterazine dioxetanone. In this study, applying molecular dynamic (MD) simulations and the hybrid quantum mechanics/molecular mechanics (QM/MM) method, we investigated a proton-transfer (PT) process taking place in CaRP obelin from Obelia longissima for emitter formation. Our calculations demonstrate a concerted PT process with a water molecule as a bridge between anionic S1-coelenteramide and the nearest histidine residue. The low activation barrier as well as the strong hydrogen-bond network between the proton donor and the proton acceptor suggests a fast PT process comparable with that of the lifetime of excited anionic S1-coelenteramide. The existence of the PT process eliminates the discrepancy between experimental and theoretical studies. The fast PT process at emitter formation can also take place in other CaRPs.


Assuntos
Hidrozoários , Prótons , Animais , Ligação de Hidrogênio , Proteínas Luminescentes
8.
Orthop Surg ; 13(7): 1960-1968, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34516712

RESUMO

OBJECTIVE: To compare the clinical efficacy between robot-assisted minimally invasive transforaminal lumbar interbody fusion (robot-assisted MIS-TLIF) and traditional open TLIF surgery in the treatment of lumbar spondylolisthesis. METHODS: According to the inclusion and exclusion criteria, 48 cases with lumbar spondylolisthesis who received surgical treatment from June 2016 to December 2017 in the spinal surgery department of Beijing Jishuitan Hospital were analyzed in this study, including 23 patients who received robot-assisted MIS-TLIF and 25 patients who received traditional open TLIF surgery. The two groups were compared in terms of pedicle screw accuracy evaluated by Gertzbein-Robbins classification on postoperative computed tomography (CT), operation time, blood loss, postoperative drainage, hospitalization, time to independent ambulation, low back pain evaluated by visual analog scale (VAS), lumbar function evaluated by Oswestry Disability Index (ODI), paraspinal muscles atrophy on magnetic resonance imaging (MRI), and complications. RESULTS: Postoperative CT showed that the rate of Grade A screws in the robot-assisted MIS-TLIF group was significantly more than that in the open surgery group (χ2 = 4.698, P = 0.025). Compared with the open surgery group, the robot-assisted MIS-TLIF group had significantly less intraoperative blood loss, less postoperative drainage, shorter hospitalization, shorter time to independent ambulation, and lower VAS at 3 days post-operation (P < 0.05). However, the duration of surgery was longer. The VAS of the robot-assisted MIS-TLIF group decreased from 6.9 ± 1.8 at pre-operation to 2.1 ± 0.8 at post-operation, 1.8 ± 0.7 at 6-month follow-up and 1.6 ± 0.5 at 2-year follow-up. The VAS of the open surgery group decreased from 6.5 ± 1.7 at pre-operation to 3.7 ± 2.1 at post-operation, 2.1 ± 0.6 at 6-month follow-up and 1.9 ± 0.5 at 2-year follow-up. The ODI of the robot-assisted MIS-TLIF group decreased from 57.8% ± 8.9% at pre-operation to 18.6% ± 4.7% at post-operation, 15.7% ± 3.9% at 6-month follow-up and 14.6% ± 3.7% at 2-year follow-up. The ODI of the open surgery group decreased from 56.9% ± 8.8% at pre-operation to 20.8% ± 5.1% at post-operation, 17.3% ± 4.2% at 6-month follow-up and 16.5% ± 3.8% at 2-year follow-up. Paraspinal muscle cross-sectional area in 2-year follow-up in patients of the open surgery group decreased significantly compared to patients of robotic-assisted MIS-TLIF group (P = 0.016). CONCLUSION: In the treatment of lumbar spondylolisthesis, robot-assisted MIS-TLIF may lead to more precise pedicle screw placement, less intraoperative blood loss, less postoperative drainage, less postoperative pain, quicker recovery, and less paraspinal muscle atrophy than traditional open surgery.


Assuntos
Vértebras Lombares/cirurgia , Procedimentos Cirúrgicos Minimamente Invasivos , Procedimentos Cirúrgicos Robóticos/métodos , Fusão Vertebral/métodos , Espondilolistese/cirurgia , Adulto , Idoso , Avaliação da Deficiência , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Medição da Dor , Resultado do Tratamento
9.
Photochem Photobiol ; 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34333799

RESUMO

Among numerous bioluminescent organisms, firefly is the most studied one. Recent experiment proposed that sulfoluciferin (SLH2 ) may serve as a storage form of luciferin (LH2 ). In the present article, we employed density functional theory calculation to uncover the mechanism and detailed process of the storage and release reactions. Due to lack of available crystallographic structure of the related enzyme, the calculation was performed on a model system. For the storage reaction, possible amino acid residues were used for imitating the protein environment. For the release reaction, the dielectric constant of 3.0 was employed to simulate the polarity of the protein cavity. The computational results indicated that the reactions from LH2 to SLH2 and from SLH2 to LH2 are both exergonic, which favor the storage and release processes and coincide with the experimental observation. Basing on experimental and current theoretical study, we supplemented the stages of LH2 storage and release in the entire bioluminescent cycle of firefly. The current theoretical calculation could inspire the study on LH2 storage and release of other bioluminescent organisms.

10.
Bioresour Technol ; 337: 125441, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34182347

RESUMO

Consolidated bio-saccharification (CBS) technology employs cellulosome-producing bacterial cells, rather than fungal cellulases, as biocatalysts for cost-effective production of lignocellulosic sugars. Extracellular ß-glucosidase (BGL) expression in the whole-cell arsenal is indispensable, due to severe cellobiose inhibition of the cellulosome. However, high-level BGL expression in Clostridium thermocellum is challenging, and the optimal BGL production level for efficient cellulose saccharification is currently unknown. Herein, we obtained new CBS biocatalysts by transforming BGL-expressing plasmids into C. thermocellum, which produced abundant BGL proteins and hydrolyzed cellulose effectively. The optimal ratio of extracellular BGL-to-cellulosome activity was determined to be in a range of 5.5 to 21.6. Despite the critical impact of BGL, both excessive BGL expression and its assembly on the cellulosome via type I cohesin-dockerin interaction led to reduced cellulosomal activity, which further confirmed the importance of coordinated BGL expression with the cellulosome. This study will further promote industrial CBS application in lignocellulose conversion.


Assuntos
Celulossomas , Clostridium thermocellum , Proteínas de Bactérias , Lignina , beta-Glucosidase
11.
BMC Ophthalmol ; 21(1): 222, 2021 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-34001069

RESUMO

BACKGROUND: Ocular toxoplasmosis caused by Toxoplasma gondii is an infectious disease which is widely distributed around the world and can present with various clinic manifestations. We are here reporting an unusual case presented with epiretinal membrane (ERM), i.e., macular pucker. CASE PRESENTATION: A 16-year old male patient visited our outpatient clinic complaining of decreased vision for about 8 years in his left eye. The best-corrected visual acuity (BCVA) was 20/20 OD and 20/400 OS. There was sensory exotropia in his left eye. No inflammatory cells or flare were found in his anterior chamber or vitreous cavity OU. An ERM involving his left macular area was found on his dilated fundus exam, which was confirmed by Optical Coherence Tomography (OCT). The ERM was found to involve his left macular area with his foveal ellipsoid zone absent. The right eye was found to be within normal limit. After a thorough discussion with the patient and his parents about treatment options and surgical benefits, risks and alternatives, we performed vitrectomy, peeled off the ERM and collected the vitreous sample for parasite testing during the procedure. Patient's blood also was drawn for serological testing. Vitreous sample analysis and serological tests confirmed ocular toxoplasmosis OS as his final diagnosis. Unfortunately, the BCVA of this patient was not improved after the surgery, but the exotropia disappeared. CONCLUSION: ERM is an unusual clinical presentation of ocular toxoplasmosis. We may add Toxoplasma gondii infection as a differential diagnosis when encountering ERM cases.


Assuntos
Membrana Epirretiniana , Toxoplasmose Ocular , Adolescente , Membrana Epirretiniana/cirurgia , Humanos , Masculino , Tomografia de Coerência Óptica , Toxoplasmose Ocular/diagnóstico , Acuidade Visual , Vitrectomia
12.
J Chem Theory Comput ; 17(6): 3483-3494, 2021 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-34002603

RESUMO

Chemiluminescence (CL) utilizing four-membered cyclic peroxides is one of the most useful analytical techniques. Up to now, the CL mechanisms for nonketone (1,2-dioxetanes) and monoketone (1,2-dioxetanones) derivatives of four-membered cyclic peroxides have been intensively studied experimentally and theoretically in the past several decades, but no general mechanism has been concluded to rationalize the origin of high-efficiency singlet chemiexcitation. In contrast, as the only diketone derivative of four-membered cyclic peroxide, the electron-transfer (ET)-catalyzed CL of 1,2-dioxetanedione (DDO), which is most suggested as a critical step in the well-known peroxyoxalate CL (POCL), has never been theoretically investigated and uncovered yet. In this work, we theoretically investigated the rubrene-catalyzed decomposition of DDO for the first time, with a hybrid quantum mechanical/molecular mechanical model and nonadiabatic molecular dynamics simulation. The computation shows a stepwise ET-catalyzed decomposition and three S0/S1 conical intersection (CI)-controlled singlet chemiexcitation. The three universal S0/S1 CIs play different roles in the high-efficiency singlet chemiexcitation in ET-catalyzed CL of DDO and should be the true origin of the high-efficiency singlet CL. We believe that the current work could not only provide a further understanding for high-efficiency singlet CL but also provide some general clues to designed new high-efficient CL systems.

13.
Ann Palliat Med ; 10(5): 5433-5443, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-34044571

RESUMO

BACKGROUND: A uperior adjacent vertebral fracture (SAVF) is a common complication after kyphoplasty. Intra-disc leakage is a significant risk factor of SAVF. However, to date, no studies on the prevention of SAVF after intra-disc leakage have been conducted. This study sought to evaluate the clinical outcome of prophylactic vertebral augmentation in high-risk patients, and explore the other risk factors of SAVF. METHODS: Of 2,571 patients who received kyphoplasty, 82 with intra-disc leakage were retrospectively enrolled in the study, and divided into 2 groups based on whether they had a superior level of prophylactic vertebral augmentation. To ensure that any possible early complications were examined, there was a minimum follow-up period of 12 months. RESULTS: The pre-operation parameters were comparable between the 2 groups. In the non-prophylactic group, 9 of 59 (15.3%) patients had SAVF superior to the level of intra-disc leakage. Of these 9 SAVF cases, 8 fractures (88.9%) occurred within 6 months after surgery. Overall, 14 (23.7%) patients developed a new fracture. In the prophylactic group, no patients had a SAVF (0.0%), but 3 (13.0%) had remote fractures (P=0.047 and 0.284). No complications were associated with vertebral augmentation. Further, the risk factor analysis showed that patients with comorbidities and a history of corticoid use had a higher risk of fracture compared with patients with none of these risk factor [odds ratios: 12.0, 95% confidence interval (CI): 1.0-143, and 34.3, 95% CI: 3.2-364.5, respectively]. CONCLUSIONS: Prophylactic vertebral augmentation can prevent SAVF without complications. Patients with comorbidities and a history of corticoid use had a higher risk of SAVF compared with patients without corticoid use. Thus, we recommend prophylactic vertebral augmentation in the selected high-risk patients.


Assuntos
Fraturas por Compressão , Cifoplastia , Fraturas da Coluna Vertebral , Cimentos Ósseos , Fraturas por Compressão/cirurgia , Humanos , Cifoplastia/efeitos adversos , Estudos Retrospectivos , Fraturas da Coluna Vertebral/cirurgia , Resultado do Tratamento
14.
J Cataract Refract Surg ; 47(12): e66-e69, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33929794

RESUMO

Implantation of an intraocular lens (IOL) after combined vitrectomy and cataract surgery is usually required to reduce postoperative refraction errors. However, because of the severe fibrosis of the anterior capsule and the adhesion between the anterior and posterior capsules, it is difficult to reopen the capsular bag to complete the secondary IOL implantation. In this study, a surgical approach is described for reopening the severe adhesion between capsules and removing the significant fibroproliferative membranous material by injecting ophthalmic viscosurgical device into the periphery of the capsular bag to separate the anterior and posterior capsules. The IOL was implanted into the capsular bag without any zonular rupture or posterior capsule tear. The position of the IOL was stable during postoperative follow-up up to 3 months. This procedure to open a severely fibrosis capsule was safe and effective.

15.
Biomol NMR Assign ; 15(2): 329-334, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-33876380

RESUMO

The cellulosome is a highly efficient cellulolytic complex containing cellulolytic enzymes and non-catalytic subunits, i.e. scaffoldins, which are assembled by the interactions between the dockerin modules of the enzymes and the cohesin modules of the primary scaffoldins. The cellulosome attaches to the cell surface via the S-layer homology (SLH) modules of the anchoring scaffoldins. Clostridium thermocellum DSM1313 is a thermophilic cellulosome-producing bacterium with great potential in lignocellulose bioconversion and biofuel production. The bacterium contains four anchoring scaffoldins ScaB, ScaC, ScaD and ScaF, among which ScaF is the only one that contains an additional module of unknown function (ScaF-X) between the cohesin and SLH modules. The gene of ScaF is located outside the scaffoldin gene cluster of scaA, scaB, scaC and scaD. Previous studies showed unique regulation properties and function of ScaF compared to other anchoring scaffoldins, which might be related to the additional ScaF-X module. Here we report the NMR chemical shift assignments of ScaF-X from C. thermocellum DSM1313. The well-dispersed NMR spectrum and the secondary structure prediction based on the chemical shifts of ScaF-X indicated that ScaF-X is a well-folded protein module. The chemical shift assignments provide the basis for future studies on the structure of this module and its function in cellulosomes.

16.
Appl Microbiol Biotechnol ; 105(6): 2455-2472, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33606076

RESUMO

Butanol inhibits bacterial activity by destroying the cell membrane of Clostridium acetobutylicum strains and altering functionality. Butanol toxicity also results in destruction of the phosphoenolpyruvate-carbohydrate phosphotransferase system (PTS), thereby preventing glucose transport and phosphorylation and inhibiting transmembrane transport and assimilation of sugars, amino acids, and other nutrients. In this study, based on the addition of exogenous butanol, the tangible macro indicators of changes in the carbon ion beam irradiation-mutant Y217 morphology were observed using scanning electron microscopy (SEM). The mutant has lower microbial adhesion to hydrocarbon (MATH) value than C. acetobutylicum ATCC 824 strain. FDA fluorescence intensity and conductivity studies demonstrated the intrinsically low membrane permeability of the mutant membrane, with membrane potential remaining relatively stable. Monounsaturated FAs (MUFAs) accounted for 35.17% of the mutant membrane, and the saturated fatty acids (SFA)/unsaturated fatty acids (UFA) ratio in the mutant cell membrane was 1.65. In addition, we conducted DNA-level analysis of the mutant strain Y217. Expectedly, through screening, we found gene mutant sites encoding membrane-related functions in the mutant, including ATP-binding cassette (ABC) transporter-related genes, predicted membrane proteins, and the PTS transport system. It is noteworthy that an unreported predicted membrane protein (CAC 3309) may be related to changes in mutant cell membrane properties. KEY POINTS: • Mutant Y217 exhibited better membrane integrity and permeability. • Mutant Y217 was more resistant to butanol toxicity. • Some membrane-related genes of mutant Y217 were mutated.


Assuntos
Butanóis , Clostridium acetobutylicum , 1-Butanol , Butanóis/toxicidade , Proteínas de Membrana
17.
J Org Chem ; 86(6): 4472-4482, 2021 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-33634700

RESUMO

Reacting with H2O2, tetrachloro-1,4-benzoquinone (TCBQ) produces chemiluminescence (CL), but chloranilic acid (CA), the dihydroxylation product of TCBQ, does not. However, an unprecedented strong CL generates from CA/H2O2 in the presence of Co(II). Why? We performed quantum chemical calculations on the entire reaction process of CA/H2O2 and CA/H2O2/Co(II) systems. The computational results indicate: for CA/H2O2 system, the reason leading to non-CL as: there is no free •OH produced by CA/H2O2, which prevents the subsequent reaction from taking place; for CA/H2O2/Co(II) system, the chemical process resulting in the CL as: First, a neutral dioxetane is formed via six sequential reactions. Then, the neutral dioxetane decomposes to generate a neutral excited-state (S1) product via a gradually reversible charge transfer initiated luminescence mechanism. A conical intersection of the ground and the S1-state potential energy surfaces facilitates the production of the S1-state product. Ultimately, the neutral S1-state product emits light as a practical light emitter. The key component for forming dioxetane and the following CL is the intrinsically generated •OH, which is roaming around at the region of C2 atoms of the CA moiety, instead of being free. The quantum chemical calculations supported the experimental observation and conclusion by providing the mechanistic explanation in detail.

18.
J Org Chem ; 86(2): 1874-1881, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-33397105

RESUMO

As the only genetically encodable bioluminescent system among eukaryotes to date, bioluminescent fungi can unceasingly emit green light for days. Cross-reactions among four lineages of luminescent fungi suggest that all of them share a common bioluminescent mechanism. A series of excellent experiments by Yampolsky's group have revealed the key components in fungal bioluminescence (BL) from luciferin to light emission. However, the detailed underlying mechanism and processes remain unknown. By performing multireference and (time dependent) density functional theory calculations, we clearly described the bioluminescent process at the molecular and electronic state level. The fungal BL is initiated by the cycloaddition of O2 to luciferin to form an α-pyrone endoperoxide high-energy intermediate (II). This oxygenation is not initiated by a single-electron transfer as it is in firefly BL, but it is explained by a charge transfer followed by a spin inversion mechanism. The thermolysis of II generates oxyluciferin at the first singlet excited state (S1) through a zwitterion intermediate (III). A chemical form of the S1-state oxyluciferin, E-V(3)*, has the potential to be a light emitter. The current theoretical calculation provides great detail for deeply understanding the chemical processes in fungal BL and in chemiluminescence involving α-pyrone endoperoxide.


Assuntos
Fungos , Luminescência , Teoria da Densidade Funcional , Medições Luminescentes , Modelos Teóricos , Pironas
19.
Chemistry ; 27(18): 5712-5720, 2021 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-33270291

RESUMO

A first-generation pair of chemiluminescent formaldehyde (FA) probes (CFAP540 and CFAP700) was reported recently. CFAP540 and CFAP700, with high selectivity and sensitivity to FA, are, respectively, suitable in cell and in vivo. Experimentalists have confirmed that both probes utilize a general 2-aza-Cope FA-reactive trigger and a chemiluminogenic phenoxydioxetane scaffold. The mechanism and detailed process of CFAP chemiluminescence (CL) remain largely unknown. In the present paper, (time-dependent) density functional theory calculations are performed on the entire reaction process of CFAP540 with FA to produce CL. The calculations elucidated the CL-producing process: FA initiates the decomposition of CFAP540 by dehydration condensation, and a phenoxy 1,2-dioxetane is formed through a series of reactions of aza-Cope rearrangement, hydrolysis of imine, and ß-elimination of alkoxyl group. Afterwards, the produced phenoxy 1,2-dioxetane decomposes to produce the m-oxybenzoate derivative in the first singlet state (S1 ) via two crossings between potential energy surfaces of the ground state (S0 ) and S1 state. This m-oxybenzoate derivative was assigned as the light emitter of the CFAP540 CL. The CL-producing process and assignment of the light emitter of CFAP700 CL are similar with the corresponding ones of CFAP540. By analyzing the D-π-A architecture of the light emitters of CFAP540 and CFAP700, a series of CFAPs is theoretically designed and a scheme to modulate their CL from visible to near-infrared region is proposed by adjusting the length and structure of the π-bridge.


Assuntos
Formaldeído , Luminescência
20.
Int J Biol Macromol ; 170: 196-206, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33347927

RESUMO

Marine microalgae are promising sources of novel glycoside hydrolases (GHs), which have great value in biotechnical and industrial applications. Although many GH1 family ß-glucosidases have been extensively studied, studies on ß-glucosidases from microalgae are rare, and no structure of algal GH1 ß-glucosidase has been reported. Here, we report the biochemical and structural study of a GH1 ß-glucosidase BGLN1 from Nannochloropsis oceanica, an oleaginous microalga. Phylogenetic analysis of BGLN1, together with the known structures of GH1 ß-glucosidases, has indicated that BGLN1 is branched at the root of the eukaryotic part of the phylogenetic tree. BGLN1 showed higher activity against laminaribiose compared to cello-oligosaccharides. Unlike most of the other GH1 ß-glucosidases, BGLN1 is partially inhibited by metal ions. The crystal structure of BGLN1 revealed that BGLN1 adopts a typical (α/ß)8-barrel fold with variations in loops and N-terminal regions. BGLN1 contains extra residues at the N-terminus, which are essential for maintaining protein stability. BGLN1 has a more acidic substrate-binding pocket than other ß-glucosidases, and the variations beyond the conserved -1 site determine the substrate specificity. These results indicate that GH enzymes from microalgae may have unique structural and functional features, which will provide new insight into carbohydrate synthesis and metabolism in marine microalgae.


Assuntos
Microalgas/enzimologia , Estramenópilas/enzimologia , beta-Glucosidase/química , Sequência de Aminoácidos , Sítios de Ligação , Cristalização , Dissacarídeos/metabolismo , Microalgas/genética , Modelos Moleculares , Simulação de Acoplamento Molecular , Oligossacarídeos/metabolismo , Fases de Leitura Aberta , Filogenia , Ligação Proteica , Processamento de Proteína Pós-Traducional , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Estramenópilas/genética , Relação Estrutura-Atividade , Especificidade por Substrato , beta-Glucosidase/genética , beta-Glucosidase/isolamento & purificação
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