RESUMO
The assembly of metal nanoparticles and targets to be detected in a small light probe volume is essential for achieving sensitive in-solution surface-enhanced Raman spectroscopy (SERS). Such assemblies generally require either chemical linkers or templates to overcome the random diffusion of the colloids unless the aqueous sample is dried. Here, a facile method is reported to produce 3D multiscale assemblies of various colloids ranging from molecules and nanoparticles to microparticles for sensitive in-solution SERS detection without chemical linkers and templates by exploiting photothermally driven convective flow. The simulations suggest that colloids sub 100 nm in diameter can be assembled by photothermally driven convective flow regardless of density; the assembly of larger colloids up to several micrometers by convective flow is significant only if their density is close to that of water. Consistent with the simulation results, the authors confirm that the photothermally driven convective flow is mainly responsible for the observed coassembly of plasmonic gold nanorods with either smaller molecules or larger microparticles. It is further found that the coassembly with the plasmonic nanoantennae leads to dramatic Raman enhancements of molecules, microplastics, and microbes by up to fivefold of magnitude compared to those measured in solution without the coassembly.
Assuntos
Nanopartículas Metálicas , Plásticos , Coloides/química , Ouro/química , Nanopartículas Metálicas/química , Análise Espectral Raman/métodosRESUMO
Waterproof membranes have higher initial strength, faster construction, and better waterproofing than conventional sheet membranes. In addition, their polymer constituents have much higher interfacial adhesion and tensile strength than those of conventional materials. However, despite their advantages, waterproof membranes are not widely used in civil construction. This study evaluates the material properties and interface parameters of a waterproof membrane by considering the results of laboratory experiments and numerical analysis. Since the contact behavior of a membrane at its interface with shotcrete is important for understanding the mechanism of the support it offers known as a shotcrete tunnel lining, modeling should adopt appropriate contact conditions. The numerical analysis identifies the suitability and contact conditions of the waterproof membrane in various conditions.
RESUMO
In recent nanobiotechnology developments, a wide variety of functional nanomaterials and engineered biomolecules have been created, and these have numerous applications in cell biology. For these nanomaterials to fulfill their promises completely, they must be able to reach their biological targets at the subcellular level and with a high level of specificity. Traditionally, either nanocarrier- or membrane disruption-based method has been used to deliver nanomaterials inside cells; however, these methods are suboptimal due to their toxicity, inconsistent delivery, and low throughput, and they are also labor intensive and time-consuming, highlighting the need for development of a next-generation, intracellular delivery system. This study reports on the development of an intracellular nanomaterial delivery platform, based on unexpected cell-deformation phenomena via spiral vortex and vortex breakdown exerted in the cross- and T-junctions at moderate Reynolds numbers. These vortex-induced cell deformation and sequential restoration processes open cell membranes transiently, allowing effective and robust intracellular delivery of nanomaterials in a single step without the aid of carriers or external apparatus. By using the platform described here (termed spiral hydroporator), we demonstrate the delivery of different nanomaterials, including gold nanoparticles (200 nm diameter), functional mesoporous silica nanoparticles (150 nm diameter), dextran (hydrodynamic diameters between 2-55 nm), and mRNA, into different cell types. We demonstrate here that the system is highly efficient (up to 96.5%) with high throughput (up to 1 × 106 cells/min) and rapid delivery (â¼1 min) while maintaining high levels of cell viability (up to 94%).
Assuntos
Dextranos/farmacologia , Sistemas de Liberação de Medicamentos , Nanoestruturas/química , Linhagem Celular Tumoral , Sobrevivência Celular , Dextranos/química , Humanos , Células K562 , Dispositivos Lab-On-A-ChipRESUMO
Chemical disinfectants such as 5-chloro-2-methylisothiazol-3(2H)-one/2-methyl-4-isothiazolin-3-one (CMIT/MIT) have been widely used in commercial products and humidifiers to prevent the growth of microorganisms. However, as continuous inhalation of CMIT/MIT is a fatal health risk, the concentration of its commercially available form is strictly regulated. Nonetheless, there are limited reports on effective methods for the quick and easy detection of CMIT/MIT. In this study, we have demonstrated rapid and convenient plasmonic methods for the dual-mode detection of CMIT/MIT using gold nanoplasmonic particles (GNPs) and understood the underlying molecular mechanism via additional analyses with microscopic and spectroscopic tools. In the presence of CMIT/MIT, the GNPs can rapidly aggregate due to molecular specific interactions with their capping agents and resultant reaction products. This target-mediated aggregation of the GNPs is represented by a visible color change of the solution from red to purple within just 3 min. By adjusting the reaction ratio between the CMIT/MIT and the GNPs, we could observe a marked color change at the regulation level (15 ppm) with naked eyes without any instruments. In addition, the concentration-dependent Raman spectral change in the reaction solution allows us to crosscheck the observed colorimetric responses both quantitatively and qualitatively based on molecular fingerprint spectra. Therefore, our detection protocol provides a powerful way to develop a high-throughput screening method to ensure that the level of the CMIT/MIT ingredients remains within the regulatory concentration.
Assuntos
Desinfetantes/análise , Ouro/química , Nanopartículas Metálicas/química , Tiazóis/análise , Colorimetria , Concentração de Íons de Hidrogênio , Análise Espectral RamanRESUMO
Photothermal conversion effect of plasmonic nanostructures is considered as a promising technique for cellular and molecular manipulations owing to controllability of local temperature. Therefore, this technique has been extensively applied to biological studies such as controlling cellular behavior, delivery of biologics, and biomolecular detection. Herein, we propose a novel method for directed cell positioning and photothermally modulated molecular delivery to the cells using patterned plasmonic interfaces. Plasmonic substrates with gold nanorods (GNRs) and cell adhesion molecules fabricated by microcontact printing are optimized for cellular positioning on designated patterns. Through the photothermal conversion effect of GNRs on the pattern, we further demonstrate on-demand, light-induced delivery of drug molecules to the target cells. We expect that this approach will provide a new way to study single cellular behaviors and enhance molecular delivery to the target cells.
Assuntos
Sistemas de Liberação de Medicamentos , Hipertermia Induzida , Fototerapia , Linhagem Celular Tumoral , Ouro/química , Humanos , Nanotubos/química , Nanotubos/ultraestrutura , ImpressãoRESUMO
Licochalcone B (Lico B), which is normally isolated from the roots of Glycyrrhiza inflata (Chinese Licorice), generally classified into organic compounds including retrochalcones. Potential pharmacological properties of Lico B include anti-inflammatory, anti-bacterial, anti-oxidant, and anti-cancer activities. However, its biological effects on melanoma and squamous cell carcinoma (SCC) are unknown. Based on these known facts, this study investigated the role of Lico B in apoptosis, through the extrinsic and intrinsic pathways and additional regulation of specificity protein 1 in human skin cancer cell lines. Annexin V/7-aminoactinomycin D staining, western blot analysis, mitochondrial membrane potential assay, and an anchorage-independent cell transformation assay demonstrated that Lico B treatment of human melanoma and SCC cells significantly inhibited cell proliferation and induced apoptotic cell death. More specifically, Lico B induced apoptosis through the regulation of specificity protein 1 and apoptosis-related proteins including CCAAT/enhancer-binding protein homologous protein, death receptors, and poly (ADP-ribose) polymerase. These results indicate that Lico B has apoptotic effect on A375 and A431 skin cancer cells, suggesting the potential value of Lico B for the treatment of human melanoma and SCC. Copyright © 2017 John Wiley & Sons, Ltd.
Assuntos
Apoptose/efeitos dos fármacos , Produtos Biológicos/química , Carcinoma de Células Escamosas/tratamento farmacológico , Chalconas/química , Melanoma/tratamento farmacológico , Neoplasias Cutâneas/tratamento farmacológico , Carcinoma de Células Escamosas/patologia , Humanos , Melanoma/patologia , Neoplasias Cutâneas/patologia , Melanoma Maligno CutâneoRESUMO
Licochalcone A (LCA), isolated from the root of Glycyrrhiza inflata, are known to have medicinal effect such as anti-oxidant, anti-bacterial, anti-viral, and anti-cancer. Though, as a pharmacological mechanism regulator, anti-cancer studies on LCA were not investigated in human breast cancer. We investigated the anti-proliferative and apoptotic effect of LCA in human breast cancer cells MCF-7 and MDA-MB-231 through MTS assay, PI staining, Annexin-V/7-AAD assay, mitochondrial membrane potential assay, multi-caspase assay, RT-PCR, Western blot analysis, and anchorage-independent cell transformation assay. Our results showed the little difference between two cells, as MCF-7 cell is both estrogen/progesterone receptor positive, there were only effect on Sp1 protein level, but not in mRNA level. Adversely, estrogen/progesterone/human epidermal growth factor receptor 2 triple negative, MDA-MB-231 showed decreased Sp1 mRNA, and protein levels. To confirm the participation of Sp1 in breast cancer cell viability, siRNA techniques were introduced. Both cells showed dysfunction of mitochondrial membrane potential and mitochondrial ROS production, which reflects it passed intracellular mitochondrial apoptosis pathway. Additionally, LCA showed the anti-proliferative and apoptotic effect in breast cancer cells through regulating Sp1 and apoptosis-related proteins in a dose- and a time-dependent manner. Consequently, LCA might be a potential anti-breast cancer drug substitute. J. Cell. Biochem. 118: 4652-4663, 2017. © 2017 Wiley Periodicals, Inc.
Assuntos
Neoplasias da Mama/tratamento farmacológico , Chalconas/farmacologia , Proteínas de Neoplasias/metabolismo , Fator de Transcrição Sp1/metabolismo , Apoptose/efeitos dos fármacos , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Sobrevivência Celular/efeitos dos fármacos , Feminino , Humanos , Células MCF-7 , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/metabolismo , Mitocôndrias/patologiaRESUMO
BACKGROUND: Mastectomy is an optional surgical management of breast cancer, but it can cause significant adverse reactions. Breast reconstruction is a concern in post-mastectomy recovery. We assessed the oncologic safety and patient satisfaction following immediate breast reconstruction using an implant or tissue expander. METHODS: We retrospectively reviewed all patients who underwent reconstruction with an implant or tissue expander immediately after mastectomy. Seventy-seven patients underwent breast reconstruction at a general hospital breast cancer center from January 2008 to December 2010. Fourteen patients were excluded due to loss at follow-up, so 63 patients were included in this study. Questionnaires were sent to all patients to assess patient satisfaction. RESULTS: Mean age was 44.1 years (range 29-64). After a median follow-up period of 22.4 months, there was 1 case of locoregional recurrence, 1 case of distant metastasis, and an overall breast cancer-specific survival of 100 %. Overall rate of major complications, such as nipple areolar complex (NAC) necrosis and implant removal, was 11.1 % (7 patients). Of the 10 patients who had NAC necrosis, 6 patients improved after observation and 4 patients had NAC excision. Three patients had their implant removed due to severe infection, leakage, and dissatisfaction, respectively. There were 32 cases of total mastectomy (TM), 12 cases of skin-sparing mastectomy (SSM), and 19 cases of NAC-sparing mastectomy (NSM). According to the questionnaire, 84.1 % were satisfied with the general operational result and 77.8 % with the cosmetic result. Of the 31 patients who received conservative surgery, 87.1 % were satisfied with the general result and 83.9 % with the cosmetic result. CONCLUSIONS: Immediate breast reconstruction using an implant after mastectomy was technically feasible and oncologically safe. In addition, the reconstruction resulted in a relatively high rate of patient satisfaction. Further long-term studies are warranted to confirm these findings.
Assuntos
Implantes de Mama , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/patologia , Carcinoma Intraductal não Infiltrante/patologia , Mamoplastia/métodos , Mastectomia/métodos , Dispositivos para Expansão de Tecidos , Adulto , Neoplasias da Mama/cirurgia , Carcinoma Ductal de Mama/cirurgia , Carcinoma Intraductal não Infiltrante/cirurgia , Estudos de Casos e Controles , Feminino , Seguimentos , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Satisfação do Paciente , Prognóstico , Estudos Retrospectivos , Inquéritos e Questionários , Fatores de TempoAssuntos
Infartos do Tronco Encefálico/diagnóstico , Bulbo/patologia , Bexiga Urinária Hiperativa/diagnóstico , Incontinência Urinária de Urgência/diagnóstico , Doença Aguda , Infartos do Tronco Encefálico/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Bexiga Urinária Hiperativa/complicações , Incontinência Urinária de Urgência/etiologiaRESUMO
The purpose of this study is to assess the technical feasibility and clinical efficacy of percutaneous transluminal angioplasty and stenting (PTAS) for symptomatic stenosis of the intracranial extradural (petrous and cavernous) internal carotid artery (ICA).Review of medical records identified 26 consecutive patients who underwent PTAS using a balloon-expandable coronary stent (n = 15, 57.7%) or a Wingspan self-expandable stent (n = 11, 42.3%) for treatment of severe stenosis (>70%) involving the intracranial extradural ICA. The inclusion criteria were transient ischemic attack with an ABCD(2) score of ≥3 (n = 12, 46.2%) or minor stroke with an NIHSS score of ≤4 (n = 14, 53.8%). Technical success rates, complications, and angiographic and clinical outcomes were analyzed retrospectively.PTAS was technically successful in all patients. The mean stenosis ratio decreased from 77.1% to 10.0% immediately after PTAS. The overall incidence of procedural complications was 23.1%, and the postoperative permanent morbidity/mortality rate was 7.7%. A total of 22 patients were tracked over an average period of 29.9 months. During the observation period, 20 patients (90.9%) had no further cerebrovascular events and stroke recurrence occurred in two patients (9.1%), resulting in an annual stroke risk of 3.7%. Two cases (11.1%) of significant in-stent restenosis (>50%) were found on follow-up angiography (n = 18).PTAS for severe stenosis (>70%) involving the intracranial extradural ICA showed a good technical feasibility and favorable clinical outcome in patients with transient ischemic attack or minor stroke.
Assuntos
Angioplastia/métodos , Artéria Carótida Interna/cirurgia , Estenose das Carótidas/complicações , Estenose das Carótidas/cirurgia , Ataque Isquêmico Transitório/etiologia , Procedimentos Neurocirúrgicos/métodos , Stents , Acidente Vascular Cerebral/etiologia , Adulto , Idoso , Artéria Carótida Interna/diagnóstico por imagem , Estenose das Carótidas/diagnóstico por imagem , Angiografia Cerebral , Estudos de Viabilidade , Feminino , Seguimentos , Oclusão de Enxerto Vascular/epidemiologia , Humanos , Ataque Isquêmico Transitório/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Acidente Vascular Cerebral/diagnóstico por imagem , Resultado do TratamentoRESUMO
OBJECTIVE: Collateral flow is important for ischemic brain tissue after an acute occlusion of the cerebral artery. The purpose of this study was to evaluate baseline collateral flow, on CT angiography (CTA), as a predictor of functional outcome in patients who had endovascular recanalization, after acute pure first segment (M1) occlusion of the middle cerebral artery (MCA). METHODS: Thirty patients with acute pure M1 occlusion treated by endovascular recanalization, who were ineligible for intravenous thrombolysis or resistant to intravenous thrombolysis, were reviewed. The relationship between baseline collateral flow, on CTA, and functional outcome, was analyzed. In addition, other factors affecting clinical outcome were assessed. RESULTS: The mean NIHSS score on admission was 16.87±4.86 (7-24). The mean time interval between onset of stroke symptoms and recanalization was 324.37±68.38 (210-463) min. Successful recanalization (TICI 2b-3) was achieved in 18 patients (60%). Twenty-seven of 30 patients improved their NIHSS score (mean 8.4); NIHSS score 8.9±5.4 (median 10, range 0-16) at seven days. Two patients had aggravated symptoms and one patient had no change on the NIHSS score. At 90 days after recanalization, a modified Rankin Scale (mRS) of ≤3 was achieved in 15 patients (50%) and a mRS of ≤2 was achieved in nine patients (30%). Symptomatic intra-cerebral hemorrhage occurred in two patients (6.7%). Multivariate regression analysis showed an initial NIHSS score (p=0.004), grade of baseline collateral flow on CTA (p=0.025), presence of diabetes mellitus (p=0.037), and TICI scale (p=0.049) were factors associated with an improved NIHSS. For the mRS at 90 days, only the grade of the baseline collateral flow on CTA was associated with a good functional outcome (p=0.013). CONCLUSIONS: The results of this study suggest that the grade of baseline collateral flow, on CTA, is an independent predictor of functional outcome for endovascular recanalization of acute pure M1 occlusion of the middle cerebral artery.
Assuntos
Circulação Cerebrovascular/fisiologia , Procedimentos Endovasculares/métodos , Infarto da Artéria Cerebral Média/diagnóstico por imagem , Infarto da Artéria Cerebral Média/cirurgia , Avaliação de Resultados em Cuidados de Saúde , Adulto , Idoso , Idoso de 80 Anos ou mais , Angiografia Cerebral , Hemorragia Cerebral , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
We prospectively recruited 10 patients who presented with urinary retention as a neurological deficit that was attributable to lateral medullary infarction. Of these, 9 patients underwent a urodynamic study, which demonstrated detrusor underactivity of the bladder in 7 patients. Urinary retention developed mainly when the lesions involved the lateral tegmentum of the middle or caudal medulla. We concluded that interruption of the descending pathway from the pontine micturition center to the sacral spinal cord in the lateral medulla was responsible for the development of urinary retention.
Assuntos
Isquemia Encefálica/diagnóstico , Bulbo/patologia , Tratos Piramidais/anatomia & histologia , Acidente Vascular Cerebral/diagnóstico , Retenção Urinária/diagnóstico , Idoso , Isquemia Encefálica/complicações , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Acidente Vascular Cerebral/complicações , Retenção Urinária/etiologiaRESUMO
The effect of dilute sodium hydroxide (NaOH) on reed straw structural change at 105 degreeC temperature was evaluated in this study. Various concentrations of NaOH (1% to 2.5%) were used for pretreatment of reed straw at 105 degreeC for 10min. Scanning electron microscopy, atomic force microscopy and Fourier transform infrared spectroscopy studies showed that 2% and 2.5% NaOH pretreated sample exposed more cellulose fibers compared with other treatments. The cellulose crystalline index was increased by the 1% to 2.0% NaOH treatments and slightly lowered by the 2.5% NaOH treatment due to destructing cellulose fibres. Two per cent NaOH pretreatment caused 69.9% lignin removal, whereas 2.5% NaOH pretreatment removed 72.4% lignin. Besides, reed straw, when pretreated at 2% and 2.5% NaOH, resulted 56.4% and 60.5% hemicellulose removal, respectively. However, the difference in removal of lignin and hemicellulose between 2% and 2.5% NaOH treated reed straw was very marginal. In addition, very negligible increase of cellulose level was estimated, amounting 78.8% and 76.6% in 2.5% and 2% NaOH-treated sample, respectively. Moreover, after 72 h, reducing sugar yield was 81.2% and 83.3% using enzyme loading of 15 FPU (g dry biomass)-' and 30 IU (g dry biomass)- and xylanase 4 FXU (g dry biomass)-1 from 2% and 2.5% NaOH pretreated reed straw, respectively. Reducing sugar yield was increased very marginally when NaOH concentration increased from 2% to 2.5% for reed straw pretreatment. Therefore, 2% NaOH is supposed to be effective for reed straw pretreatment at this mentioned condition.
Assuntos
Celulose/química , Celulose/ultraestrutura , Componentes Aéreos da Planta/química , Componentes Aéreos da Planta/ultraestrutura , Poaceae/química , Poaceae/ultraestrutura , Hidróxido de Sódio/química , Álcalis/química , Concentração de Íons de Hidrogênio , Teste de MateriaisAssuntos
Amnésia Anterógrada/etiologia , Corpo Caloso/patologia , Golpe de Calor/patologia , Hipocampo/patologia , Adolescente , Amnésia Anterógrada/patologia , Amnésia Anterógrada/psicologia , Angiografia Cerebral , Corpo Caloso/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética , Hidratação , Golpe de Calor/complicações , Hipocampo/diagnóstico por imagem , Humanos , Testes de Função Hepática , Angiografia por Ressonância Magnética , Imageamento por Ressonância Magnética , Masculino , Testes Neuropsicológicos , Tomografia por Emissão de Pósitrons , Tomografia Computadorizada por Raios XRESUMO
Two cas genes were isolated from Pectobacterium carotovorum subsp. carotovorum LY34 (Pcc LY34). Sequence analysis of the 4873 bp cloned DNA fragment (accession number AY866383) revealed two open reading frames (casF and casB) that are predicted to encode 658 and 467 amino acid proteins, respectively. The CasF protein is similar to other PTS enzyme II components. casB encodes ß-glucosidase, a member of the glycosyl hydrolase family 1. An inverted repeat sequence was identified in the casB promoter region, and was hypothesized to have a negative effect on casB transcription. Replacement of the casB promoter of Pcc LY34 with the bglB promoter activated the casB gene, consistent with the repeats inhibiting expression of casB. Purified CasB enzyme was estimated to be 53,000 Da by SDS-PAGE, and hydrolyzed salicin, arbutin, pNPG, and MUG. CasB exhibited maximal activity toward pNPG at pH 7.0 and 40 °C, and Mg(2+) is essential for its activity. Two conserved glutamate residues (Glu(177) and Glu(366)) were shown to be important for CasB activity.
Assuntos
Pectobacterium carotovorum/enzimologia , Pectobacterium carotovorum/genética , Ativação Transcricional , beta-Glucosidase/genética , beta-Glucosidase/metabolismo , DNA Bacteriano/química , DNA Bacteriano/genética , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Sequências Repetidas Invertidas , Engenharia Metabólica , Dados de Sequência Molecular , Peso Molecular , Fases de Leitura Aberta , Regiões Promotoras Genéticas , Recombinação Genética , Análise de Sequência de DNA , Especificidade por Substrato , Temperatura , Transcrição Gênica , beta-Glucosidase/químicaRESUMO
This work was conducted to evaluate the effect of dilute sodium hydroxide (NaOH) on barley straw at boiling temperature and fractionation of its biomass components into lignin, hemicellulose, and reducing sugars. To this end, various concentrations of NaOH (0.5% to 2%) were applied for pretreatment of barley straw at 105 degrees C for 10 min. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and Fourier transform infrared (FTIR) spectroscopy studies revealed that 2% NaOHpretreated barley straw exposed cellulose fibers on which surface granules were abolished due to comprehensive removal of lignin and hemicellulose. The X-ray diffractometer (XRD) result showed that the crystalline index was increased with increased concentration of NaOH and found a maximum 71.5% for 2% NaOH-pretreated sample. The maximum removal of lignin and hemicellulose was 84.8% and 79.5% from 2% NaOH-pretreated liquor, respectively. Reducing sugar yield was 86.5% from 2% NaOH-pretreated sample using an enzyme dose containing 20 FPU of cellulase, 40 IU of beta-glucosidase, and 4 FXU of xylanase/g substrate. The results of this study suggest that it is possible to produce the bioethanol precursor from barley straw using 2% NaOH at boiling temperature.
Assuntos
Hordeum/efeitos dos fármacos , Lignina/química , Lignina/ultraestrutura , Hidróxido de Sódio/química , beta-Glucosidase/metabolismo , Biocombustíveis , Biomassa , Biotecnologia/métodos , Hordeum/química , Hordeum/enzimologia , Temperatura Alta , Concentração de Íons de Hidrogênio , Hidrólise , Microscopia de Força Atômica , Polissacarídeos/química , Polissacarídeos/ultraestrutura , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
We evaluated the effect of dilute sodium hydroxide (NaOH) on wheat straw at boiling temperature for removing lignin and increasing the yield of reducing sugar. Various concentrations of NaOH (0.5% to 2%) were used for pretreating wheat straw at 105 °C for 10 min. Scanning electron microscopy, atomic force microscopy, and Fourier transform infrared spectroscopy studies revealed that the 2% NaOH-pretreated sample exposed more cellulose fiber. The maximum respective removal of lignin and hemicellulose was 70.3% and 68.2% from the 2% NaOH-pretreated liquor. The reducing sugar yield was 84.6% using an enzyme dose containing 20 FPU of cellulase, 40 IU of ß-glucosidase and 4 FXU of xylanase/g of substrate. However, 2% NaOH-treated wheat straw had the lowest crystalline index of 52.5%, due to destructured cellulose fibers. The results indicate the effectiveness of producing the bioethanol precursor from wheat straw by using 2% NaOH at boiling temperature.
Assuntos
Biocombustíveis , Etanol/metabolismo , Hidróxido de Sódio/farmacologia , Temperatura de Transição , Triticum/efeitos dos fármacos , Triticum/metabolismo , Celulose/metabolismo , Etanol/química , Hidrólise/efeitos dos fármacos , Cinética , Lignina/metabolismo , Polissacarídeos/metabolismo , Triticum/química , Triticum/enzimologiaRESUMO
This study was conducted to assess the gene duplication and diversification of tandem cellulase genes in thermophilic bacteria. The tandem cellulase genes cel5C and cel5D were cloned from Thermotoga maritima MSB8, and a survey of the thermophilic bacterial genome for tandem cel genes from the databases was carried out. A clone having 2.3 kb fragment from T. maritima MSB8 showed cellulase activity, which had two open reading frames in tandem (cel5C and cel5D). The cel5C gene has 954 bp, which encodes a protein of 317 amino acid residues with a signal peptide of 23 amino acids, and the other gene cel5D consisting of 990 bp encoding a protein of 329 amino acid residues. These two proteins have similarity with the enzymes of glycosyl hydrolase family 5. From the enzyme assay, it was observed that Cel5C was extracellular and Cel5D was intracellular cellulase. Phylogenetic and homology matrix analyses of DNA and protein sequences revealed that family 12 cellulase enzymes Cel12A and Cel12B displayed higher homology (>50 %), but Cel5C and Cel5D enzymes belong to family 5 displayed lower homology (<30 %). In addition, repeated and mirror sequences in tandem genes are supposed to show the existence of gene duplication and recombination.
Assuntos
Celulases/genética , Duplicação Gênica , Recombinação Genética , Thermotoga maritima/enzimologia , Thermotoga maritima/genética , Celulases/química , Clonagem Molecular , DNA Bacteriano/genética , Evolução Molecular , Espaço Extracelular/enzimologia , Glicosídeo Hidrolases/genética , Espaço Intracelular/enzimologia , Modelos Moleculares , Filogenia , Conformação Proteica , Thermotoga maritima/citologiaRESUMO
The gene encoding an esterase enzyme was cloned from a metagenomic library of cow rumen bacteria. The esterase gene (est5S) was 1,026 bp in length, encoding a protein of 366 amino acid residues with a calculated molecular mass of 40,168 Da. The molecular mass of the enzyme was estimated to be 40,000 Da. The Est5S protein contains the Gly-X-Ser-X-Gly motif found in most bacterial and eukaryotic serine hydrolases. However, the Asp or Glu necessary for the catalytic triad [Ser-Asp-(Glu)-His] was not present, indicating Est5S represents a novel member of the GHSQG family of esterolytic enzymes. BlastP in the NCBI database analysis of Est5S revealed homology to hypothetical proteins and it had no homology to previous known lipases and esterases. Est5S was optimally active at pH 7.0 and 40 degrees C. Among the p-nitrophenyl acylesters tested, high enzymatic activities were observed on the short-chain p-nitrophenyl acylesters, such as p-nitrophenyl acetate, etc. The conserved serine residue (Ser190) was shown to be important for Est5S activity. The primers that amplified the est5S gene did not show any relative band with 49 species of culturable rumen bacteria. This implies that a new group esterase gene, est5S, may have come from a noncultured cow rumen bacterium.
Assuntos
Bactérias/enzimologia , Esterases/genética , Esterases/metabolismo , Rúmen/microbiologia , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/metabolismo , Bovinos , Clonagem Molecular , DNA Bacteriano/química , DNA Bacteriano/genética , Estabilidade Enzimática , Esterases/química , Esterases/isolamento & purificação , Concentração de Íons de Hidrogênio , Cinética , Dados de Sequência Molecular , Peso Molecular , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Especificidade por Substrato , TemperaturaRESUMO
ß-Glucosidases are widespread in bacteria and involved in the metabolism of various carbohydrate substrates. Studying of ß-glucoside utilization (bgl) operons on operon of Pectobacterium carotovorum subsp. carotovorum LY34 (Pcc LY34) will help us understanding how ß-glucoside utilization (bgl) operon can cooperate with other systems in bacterium caused soft-rot disease. Pcc LY34 causes soft-rot disease in plants and expresses multiple enzymatic forms of ß-glucosidases. To fully explore the ß-glucoside utilization system in Pcc LY34, we have isolated a bgl operon from a genomic library for screening of ß-glucosidase activities. Sequence analysis of a 3050bp cloned DNA fragment (accession number AY870655) shows two open reading frames (bglY and bglK) that are predicted to encode proteins of 474 and 278 amino acid residues, respectively. Pair wise similarity analysis suggests BglY is a beta-glucosidase (a member of glycosyl hydrolase family 1) and BglK is a transcriptional antiterminator protein. bglY promoter region contains an inverted repeat sequence similar to transcriptional terminator. Different from other four ß-glucoside utilization operons of Pcc LY34 strain, BglY contains signal peptide sequences as extracellular ß-glucosidase. Comparisons of five ß-glucoside utilization operons of Pcc LY34 strain showed that bglYK operon does not have phosphotransferase system domain which are responsible for sugar transportation. BglY shares 33-44% identity with other four ß-glucosidases of Pcc LY34 strain. Enzyme assay showed that purified BglY enzyme hydrolyzed salicin, arbutin, pNPG, and MUG, and exhibited maximal activity at pH 7.0 and 40°C. This activity was enhanced Mg(2+). Site-directed mutagenesis revealed E166 and E371 are critical of BglY's ß-glucosidase activity.