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1.
Nat Prod Res ; : 1-5, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38501743

RESUMO

Two new megastigmane glycosides, (6 R,7E,9R)-3-oxo-α-ionyl-9-O-α-L-rhamnopyranosyl-(1''→4')-ß-D-glucopyranoside (1) and (6 R,7E,9R)-3-oxo-α-ionyl-9-O-ß-D-glucopyranosyl-(1''→6')-ß-D-glucopyranoside (2), together with six known analogues (3-8) were isolated from the leaves of Nicotiana tabacum. The structures of all metabolites were determined by comprehensive analysis of NMR and MS spectroscopic data as well as by comparison with those of previously reported. The in vitro anti-inflammatory activity of all isolates was evaluated using a lipopolysaccharide (LPS)-induced RAW264.7 cell inflammatory model, and the compounds 1, 3, 7, and 8 exhibited inhibition of LPS-induced NO production in RAW264.7 macrophage cells with IC50 values of 42.3-61.7 µM (positive control, dexamethasone, IC50 = 21.3 ± 1.2 µM).

2.
Metabolites ; 14(3)2024 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-38535318

RESUMO

Sensory attributes strongly influence consumers' preferences for products. The inoculation of the Klebsiella variicola H8 strain in a reconstituted tobacco leaf concentrate (RTLC) solution increased neutral aroma-enhancing compound (NAEC) production by 45%, decreased the nicotine level by 25%, decreased the water-soluble total sugar content by ~36%, and improved the sensory quality by 5.71%. The production of NAECs such as dihydrokiwi lactone (DHKL: 192.86%), 1,2,3,4-tetrahydro-1,1,6-trimethylnaphthalene (THTMN: 177.77%), 2,4-di-tert-butylphenol (DTBP: 25%), 4-oxoisofolkone (OIFK: 116.66%,) 1,9-heptadecadiene-4,6-diyn-3-ol (HDD: 116.67%), ß-damastrone (BDS: 116.67), and megastigmatrienone A (MSTA: 116.67%) was increased. A metagenomics analysis of the microbial community in the fermented RTLC (FRTLC) was performed to elucidate the mechanism by which NAECs were produced. As a result, 24 groups of functional genes were identified, and among them, five families of carbohydrate-active enzymes, (i) glycoside hydrolase (GH), (ii) glycosyltransferase (GT), (iii) polysaccharide lyase (PL), (iv) carbohydrate esterase (CE), and (v) auxiliary active enzyme (AA), were found to be positively correlated with the production of NAECs. However, among the GHs, the GHs annotated from the H8 strain chromosome displayed the highest relative abundance and a positive correlation with the production of NAECs. Specifically, the GH13-14, GH13-20, GH13-38, GH13-25, GH13-10, GH42, and GH28 genes of the H8 strain were relatively more abundant and were key contributors to the production of NAECs. The correlation analyses revealed that the H8 strain plays a leading role among all the microorganisms in FRTLC in the production of NAECs. Our findings support the application of Klebsiella variicola in NAEC production and a reduction in nicotine content in tobacco products.

3.
Arch Microbiol ; 204(12): 726, 2022 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-36427112

RESUMO

To improve the sensory quality of aged flue-cured tobacco (FCT), Bacillus subtilis subsp, H11 was inoculated on aged FCT leaves named Pingdingshan DCFB. The metagenome and thecharacteristic aroma substances of aged FCT with different fermentation times (0 h, 12 h, 24 h, and 36 h) were systematically analyzed. The results showed that the content of aroma components and sensory quality of aged FCT were significantly improved when the strain was treated at 35 °C with 25% moisture for 24 h. The inoculation of H11 had a strong influence on the microbial composition and metabolism of the aged FCT leaf surface. Five microorganisms Pantoea (35.04%, 20.12-56.95%), Enterobacter (22.16, 13.60-39.82%), Pseudomonas (12.12, 3.13-26.17%), Terribacillus (8.00%, 4.65-13.01%) and Bacillus (6.54%, 0.67-16.96%) accounted for the largest proportion during the process of fermentation. The content of most neutral flavor components such as ketones and aldehydes in FCT after fermentation was higher than that priorto fermentation. After 24 h fermentation, 3-furfural, 5-methylfurfural, dihydrokiwi lactone and megalotrienone increased by 71.42%, 49.19%, 21.09%, and 10.56%, respectively. Correlation analysis between groups showed that Pseudomonas was significantly correlated with (E, E)-2, 4-heptadienal (P < 0.05), Franconibacter was correlated with damascus ketone (P < 0.05), and Terribacillus was related to the production of ß-citral (P < 0.05). GH9 may be involved in the formation of damasone (P < 0.05), and 4-cyclopentene-1, 3-dione was significantly correlated with glycoside hydrolase family 5 (GH5) (P < 0.05). The correlation between 4-oxyisophorone and GH31, GH103, GH73, and GH3 was significant (P < 0.05). Microorganisms and GHs may play important roles in FCT fermentation.


Assuntos
Metagenoma , Microbiota , Nicotiana , Odorantes , Bacillus subtilis/genética , Folhas de Planta
4.
Molecules ; 27(18)2022 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-36144743

RESUMO

Natural coumarins contribute to the aroma of licorice, and they are often used as a flavoring and stabilizing agents. However, coumarins usage in food has been banned by various countries due to its toxic effect. In this study, a strain of HSM-C2 that can biodegrade coumarin with high efficiency was isolated from soil and identified as Pseudomonas putida through performing 16S rDNA sequence analysis. The HSM-C2 catalyzed the biodegradation up to 99.83% of 1 mg/mL coumarin within 24 h under optimal culture conditions, such as 30 °C and pH 7, which highlights the strong coumarin biodegrading potential of this strain. The product, such as dihydrocoumarin, generated after the biodegradation of coumarin was identified by performing GC-MS analysis. The present study provides a theoretical basis and microbial resource for further research on coumarin biodegradation.


Assuntos
Pseudomonas putida , Biodegradação Ambiental , Cumarínicos/metabolismo , DNA Ribossômico/metabolismo , Excipientes , Pseudomonas putida/genética , Pseudomonas putida/metabolismo , Solo , Microbiologia do Solo
5.
Biotechnol Lett ; 43(12): 2233-2241, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34618272

RESUMO

To characterize a novel thermophilic ß-carotene 15,15'-monooxygenase BCMO7211 isolated from the marine bacterium Candidatus Pelagibacter sp. HTCC7211. BCMO7211 was functionally overexpressed in Escherichia coli and purified to homogeneity by Ni-NTA affinity chromatography and Superdex-200 gel filtration chromatography. Labeling experiments with H218O demonstrated that the oxygen atom in the terminal aldehyde group of the produced retinal molecules was provided from both molecular oxygen and water, indicating that BCMO7211 is the first characterized bacterial ß-carotene 15,15'-monooxygenase. BCMO7211 exhibited broad carotenoid substrate specificity toward α-carotene, ß-cryptoxanthin, ß-carotene, zeaxanthin, and lutein. The optimum temperature, pH, and concentrations of the substrate and enzyme for retinal production were 60 °C, 9.0, 500 mg ß-carotene/L, and 2.5 U/ml, respectively. Under optimum conditions, 888.3 mg/L retinal was produced in 60 min with a conversion rate of 89.0% (w/w). BCMO7211 is a potential candidate for the enzymatic synthesis of retinal in biotechnological applications.


Assuntos
Organismos Aquáticos/enzimologia , Inibidores Enzimáticos/farmacologia , Rhizobiaceae/enzimologia , beta-Caroteno 15,15'-Mono-Oxigenase/química , Escherichia coli/genética , Especificidade por Substrato/genética , beta-Caroteno 15,15'-Mono-Oxigenase/antagonistas & inibidores , beta-Caroteno 15,15'-Mono-Oxigenase/genética , beta-Caroteno 15,15'-Mono-Oxigenase/isolamento & purificação
6.
Appl Environ Microbiol ; 87(14): e0032621, 2021 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-33931419

RESUMO

In the marine environment, phosphorus availability significantly affects the lipid composition in many cosmopolitan marine heterotrophic bacteria, including members of the SAR11 clade and the Roseobacter clade. Under phosphorus stress conditions, nonphosphorus sugar-containing glycoglycerolipids are substitutes for phospholipids in these bacteria. Although these glycoglycerolipids play an important role as surrogates for phospholipids under phosphate deprivation, glycoglycerolipid synthases in marine microbes are poorly studied. In the present study, we biochemically characterized a glycolipid glycosyltransferase (GTcp) from the marine bacterium "Candidatus Pelagibacter sp." strain HTCC7211, a member of the SAR11 clade. Our results showed that GTcp is able to act as a multifunctional enzyme by synthesizing different glycoglycerolipids with UDP-glucose, UDP-galactose, or UDP-glucuronic acid as sugar donors and diacylglycerol (DAG) as the acceptor. Analyses of enzyme kinetic parameters demonstrated that Mg2+ notably changes the enzyme's affinity for UDP-glucose, which improves its catalytic efficiency. Homology modeling and mutational analyses revealed binding sites for the sugar donor and the diacylglycerol lipid acceptor, which provided insights into the retaining mechanism of GTcp with its GT-B fold. A phylogenetic analysis showed that GTcp and its homologs form a group in the GT4 glycosyltransferase family. These results not only provide new insights into the glycoglycerolipid synthesis mechanism in lipid remodeling but also describe an efficient enzymatic tool for the future synthesis of bioactive molecules. IMPORTANCE The bilayer formed by membrane lipids serves as the containment unit for living microbial cells. In the marine environment, it has been firmly established that phytoplankton and heterotrophic bacteria can replace phospholipids with nonphosphorus sugar-containing glycoglycerolipids in response to phosphorus limitation. However, little is known about how these glycoglycerolipids are synthesized. Here, we determined the biochemical characteristics of a glycolipid glycosyltransferase (GTcp) from the marine bacterium "Candidatus Pelagibacter sp." strain HTCC7211. GTcp and its homologs form a group in the GT4 glycosyltransferase family and can synthesize neutral glycolipids (monoglucosyl-1,2-diacyl-sn-glycerol [MGlc-DAG] and monogalactosyl [MGal]-DAG) and monoglucuronic acid diacylglycerol (MGlcA-DAG). We also uncovered the key residues for DAG binding through molecular docking, site-direct mutagenesis, and subsequent enzyme activity assays. Our data provide new insights into the glycoglycerolipid synthesis mechanism in lipid remodeling.


Assuntos
Alphaproteobacteria/enzimologia , Glicolipídeos/química , Glicosiltransferases/química , Alphaproteobacteria/genética , Glicosilação , Glicosiltransferases/genética , Glicosiltransferases/metabolismo , Metais Pesados/química , Especificidade por Substrato
7.
Food Res Int ; 125: 108570, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31554135

RESUMO

Many dietary flavonoids existing as glycosides in fruits and vegetables are considered bioactive food components with various potential health benefits. Type 2 diabetes mellitus (T2DM) is a complex and polygenic disease with increasing global prevalence and economic burden. In this study, the hypoglycemic effect of avicularin (quercetin-3-O-α-arabinofuranoside), a flavonoid glycoside commonly found in natural plants and fruits, was determined in a high fat diet/streptozotocin induced type 2 diabetes mouse model. Our results demonstrated that dietary avicularin treatment reduced levels of fasting blood glucose, serum TG and LDL-C, liver AST and ALT, and increased hepatic glycogen in T2DM mice. Furthermore, we used RNA-Seq and iTRAQ to compare the gene and protein expression in the livers of the normal control mice (NC), diabetic control mice (DC) and avicularin treated mice (DA100). The differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) were analyzed based on gene annotations and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. Integrated analysis of the RNA-Seq and iTRAQ data indicated that the fifteen DEGs/DEPs showed the same trend in mRNA and protein expression levels in comparisons of both NC vs DC and DC vs DA100. KEGG analysis revealed that four DEGs/DEPs (PKM, PEPCK, PYG, and PLA2) in the glycolysis, gluconeogenesis, and arachidonic acid pathway, and six DEPs (Ndufb4, Ndufa6, Cox5a, Cox5b, Cox6c, and ATPSß) in the oxidative phosphorylation signaling pathway, play important roles in avicularin's hypoglycemic effect. We also found six other DEGs/DEPs related to T2DM (CA1, Serpinb6a, AK, Pcolce, Cand2, and Atp2a3), and five related to cancer (Phgdh, Tes, Papss1, Psat1, and Fam49b). We did further verify by qRT-PCR and explored the possible binding modes of avicularin with targeted proteins with molecular docking simulations. Taken together, our results demonstrated the protective effects of avicularin against diabetes and provided a global view about the system-level hypoglycemic mechanisms of avicularin by the comprehensive analysis of transcriptomic and proteomic data in T2DM mice.


Assuntos
Diabetes Mellitus Experimental/metabolismo , Flavonoides/farmacologia , Fígado/metabolismo , Proteoma/metabolismo , Transcriptoma/genética , Animais , Diabetes Mellitus Experimental/genética , Flavonoides/genética , Flavonoides/metabolismo , Masculino , Camundongos , Proteoma/efeitos dos fármacos , Transcriptoma/efeitos dos fármacos
8.
Molecules ; 24(5)2019 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-30823375

RESUMO

The Chrysanthemum morifolium flower is widely used in China and Japan as a food, beverage, and medicine for many diseases. In our work, two new caffeoylquinic acid derivatives (1, 2), a new flavanone glycoside (3), and six reported flavanones (4⁻9) were isolated and identified from the flowers of C. morifolium. The chemical structures of all isolates were elucidated by the analysis of comprehensive spectroscopic data as well as by comparison with previously reported data. The isolated constituents 1⁻8 were evaluated for their neuroprotective activity, and compounds 3 and 4 displayed neuroprotective effects against hydrogen peroxide-induced neurotoxicity in human neuroblastoma SH-SY5Y cells.


Assuntos
Chrysanthemum/química , Flavanonas , Flores/classificação , Glicosídeos , Fármacos Neuroprotetores , Ácido Quínico/análogos & derivados , Flavanonas/química , Flavanonas/farmacologia , Glicosídeos/química , Glicosídeos/farmacologia , Células Hep G2 , Humanos , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/farmacologia , Ácido Quínico/química , Ácido Quínico/farmacologia
9.
Bioresour Technol ; 274: 518-524, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30553964

RESUMO

In this study, bacterial cellulose (BC) was synthesized by Acetobacter xylinum ATCC 23767 using tobacco waste extract (TWE) as a carbon source. Nicotine was found to be an inhibitory factor for BC synthesis, but it can be removed at pH 9.0 by steam distillation. After removing nicotine, the BC production was 2.27 g/L in TWE prepared with solid-liquid (S-L) ratio at 1:10. To further enhance the BC production, two fermentation stages were performed over 16 days by re-adjusting the pH to 6.5 at 7 days, after the first fermentation stage was completed. Using this two-stage fermentation, the BC production could reach 5.2 g/L. Structural and thermal analysis by FE-SEM, FT-IR, XRD and TGA showed the properties of BC obtained from TWE were similar to that from Hestrin-Schramm (HS) medium. Considering the huge disposal tobacco waste in China, the present study provides an alternative methodology to synthesize BC.


Assuntos
Celulose/metabolismo , Gluconacetobacter xylinus/metabolismo , Nicotiana/metabolismo , Metabolismo dos Carboidratos , Carbono/metabolismo , China , Meios de Cultura , Fermentação , Espectroscopia de Infravermelho com Transformada de Fourier
10.
An Acad Bras Cienc ; 90(3): 2731-2740, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30304218

RESUMO

The DNA nuclease gene ST2109 has been cloned from the hyperthermophilic archaeon Sulfolobus tokodaii and expressed in Escherichia coli. The recombinant protein StoNurA has been purified to homogeneity by affinity chromatography and gel filtration chromatography. Biochemical analyses demonstrated that StoNurA exhibited DNA binding and 5'-3' exonuclease activities towards ssDNA and dsDNA. The temperature and pH optima of StoNurA were determined to be 65 °C and 8.0, respectively. The activity of StoNurA was found to be dependent of Mn2+, and its half-life of heat inactivation at 100 °C was 5 min. Gel filtration chromatography revealed that StoNurA could form dimers in solution. Pull-down assays also showed that StoNurA physically interacted with a DNA helicase (StoHerA). Our data suggest that NurA may play a key functional role in the processing of DNA recombinational repair.


Assuntos
DNA Arqueal/genética , Desoxirribonucleases/metabolismo , Sulfolobus/enzimologia , Cromatografia de Afinidade , Cromatografia em Gel , Clonagem Molecular , Desoxirribonucleases/genética , Concentração de Íons de Hidrogênio , Sulfolobus/genética , Sulfolobus/metabolismo , Fatores de Tempo
11.
Genome Announc ; 6(17)2018 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-29700133

RESUMO

Novosphingobium sp. HII-3, the first bacterium confirmed to degrade the cembranoid α(ß)-2,7,11-cembratriene-4,6-diol to farnesal, was isolated from cured tobacco leaf in Henan, China. Here, we report the annotated draft genome sequence of strain HII-3, which has an estimated size of 4.45 Mb and comprises 4,072 coding sequences.

12.
An Acad Bras Cienc ; 89(3 Suppl): 2033-2041, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29044312

RESUMO

The effect on different three carbon source (i.e. glucose, fructose and sucrose) on production, chemical characterization and antioxidant activity of exopolysaccharide (EPS) produced by Phellinus vaninii Ljup was investigated in this study. Amongst carbon sources examined, glucose and sucrose were favorable for the mycelia growth, while the maximum EPS yield was achieved when sucrose was employed. The predominant carbohydrate compositions in EPSs identified were gluconic acid, glucose, mannose and galactose acid. Then, FT-IR spectral analysis revealed prominent characteristic groups in EPSs. EPSs molecule exist as nearly globular shape form in aqueous solution. The variation also affects antioxidant activities by investigated by using hydroxyl and DPPH radical scavenging assay. Sucrose was best carbon source from the viewpoint of antioxidant activity due to the relatively high contents of galactose in the EPS with moderate molecular weight and polydispersity.


Assuntos
Carbono/metabolismo , Polissacarídeos Fúngicos , Polissacarídeos Bacterianos/metabolismo , Frutose/metabolismo , Glucose/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier , Sacarose/metabolismo
13.
Biotechnol Lett ; 39(7): 1019-1024, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28353147

RESUMO

OBJECTIVES: To investigate the final product of the bioconversion of lutein by a novel lutein-degrading bacterium, Enterobacter hormaechei A20, and the kinetics of the process. RESULTS: A new product, 8-methyl-α-ionone, was resolved by GC-MS. The compound was further identified by NMR. A conversion yield of 90% was achieved by E. hormaechei in 36 h with 10 g lutein l-1. CONCLUSIONS: This is the first report of the bioconversion of lutein to form 8-methyl-α-ionone. A degradation pathway is proposed.


Assuntos
Biotransformação , Enterobacter/metabolismo , Luteína/metabolismo , Norisoprenoides/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Redes e Vias Metabólicas , Fatores de Tempo
14.
Appl Microbiol Biotechnol ; 101(10): 4279-4287, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28184985

RESUMO

Before being subjected to the aging process, raw tobacco leaves (TLs) must be threshed and redried. We propose that threshing and redrying affect the bacterial communities that inhabit the TL surface, thereby influencing the aging process. However, these effects remain unclear. In this study, Illumina sequencing was applied to analyze the bacterial communities on both raw and redried TLs. Shannon's diversity value decreased from 3.38 to 2.52 after the threshing and redrying processes, indicating a large reduction in TL bacterial diversity. The bacterial communities also largely differed between raw TLs and redried TLs. On unaged raw TLs, Proteobacteria was the most dominant phylum (56.15%), followed by Firmicutes (38.99%). In contrast, on unaged redried TLs, Firmicutes (76.49%) was the most dominant phylum, followed by Proteobacteria (21.30%). Thus, the dominant genus Proteobacteria, which includes Sphingomonas, Stenotrophomonas, and Pantoea, decreased after the threshing and redrying processes, while the dominant genus Firmicutes, which includes Bacillus and Lactococcus, increased. Changes in the bacterial communities between raw and redried TLs were also noted after 1 year of aging. The relative abundance of dominant Proteobacteria taxa on raw TLs decreased from 56.15 to 16.92%, while the relative abundance of Firmicutes taxa increased from 38.99 to 79.10%. However, small changes were observed on redried TLs after 1 year of aging, with a slight decrease in Proteobacteria (21.30 to 17.64%) and a small increase in Firmicutes (76.49 to 79.10%). Based on these results, Firmicutes taxa may have a higher tolerance for extreme environments (such as high temperature or low moisture) than Proteobacteria bacteria. This study is the first report to examine the effects of threshing and redrying on bacterial communities that inhabit TLs.


Assuntos
Firmicutes/isolamento & purificação , Consórcios Microbianos/fisiologia , Nicotiana/microbiologia , Folhas de Planta/microbiologia , Proteobactérias/isolamento & purificação , Firmicutes/genética , Firmicutes/fisiologia , Variação Genética , Sequenciamento de Nucleotídeos em Larga Escala , Consórcios Microbianos/genética , Filogenia , Proteobactérias/genética , Proteobactérias/fisiologia , RNA Ribossômico 16S
15.
Biotechnol Appl Biochem ; 64(6): 843-850, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27958658

RESUMO

Phytosterols have been demonstrated to be precursors of polycyclic aromatic hydrocarbons (PAHs) formed during biomass pyrolysis. Here, a novel Paenibacillus sp. was evaluated for its ability to degrade phytosterols in tobacco waste extract (TWE). The optimal conditions for cell growth and stigmasterol (a representative of phytosterols) degradation were 37 °C, pH 7.0, 1.0 g/L yeast extract, and 6.0 g/L glucose. Paenibacillus sp. could degrade stigmasterol under high concentrations of glucose (up to 130 g/L) and tolerate wide pH (5.0-9.0) and temperature (25-42 °C) ranges. The new strain could degrade stigmasterol completely into CO2 and H2 O, and no intermediate steroids were detected during the degradation process. Phytosterol degradation in TWE was demonstrated by high-performance liquid chromatography-tandem mass spectrometry. Under optimal conditions (37 °C, pH 7.0, with the exponential-phase cells), the total degradation ratio of phytosterols reached 38.5% in TWE, including 45.2% of stigmasterol, 37.4% of ß-sitosterol, 27.3% of campesterol, and 28.7% of cholesterol. These results showed that Paenibacillus sp. is a candidate for phytosterol degradation in TWE and other biomass and is potentially useful in reducing the PAHs generated from biomass pyrolysis.


Assuntos
Nicotiana/metabolismo , Fitosteróis/metabolismo , Extratos Vegetais/metabolismo , Proliferação de Células , Cromatografia Líquida de Alta Pressão , Concentração de Íons de Hidrogênio , Paenibacillus/citologia , Paenibacillus/metabolismo , Filogenia , Fitosteróis/química , Fitosteróis/isolamento & purificação , Extratos Vegetais/química , Espectrometria de Massas em Tandem , Temperatura , Nicotiana/química
16.
Biotechnol Appl Biochem ; 64(4): 525-531, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27222303

RESUMO

A glycoside hydrolase from Penicillium oxalicum BL 3005 was purified to apparent homogeneity. Its molecular mass was estimated to be 90 kDa by SDS-PAGE. The enzyme was identified to be a new member of family-3 by peptide sequence. High transglycosylation activity was found in the hydrolytic reaction of cellobiose. In the reaction, salidroside (4-hydroxyphenethyl O-ß-d-glucopyranoside) was formed by adding tyrosol as the glycosyl acceptor. The optimum reaction pH and temperature were pH 6.5 and 55 °C, respectively. The maximum yield of salidroside was almost 20 g/L. These results indicated that the ß-glucosidase of P. oxalicum can be considered as a very promising catalyst for the synthesis of salidroside.


Assuntos
Biocatálise , Glucosídeos/biossíntese , Glicosídeo Hidrolases/metabolismo , Penicillium/enzimologia , Álcool Feniletílico/análogos & derivados , Eletroforese em Gel de Poliacrilamida , Glucosídeos/química , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/isolamento & purificação , Glicosilação , Peso Molecular , Fenóis/química , Álcool Feniletílico/química , Álcool Feniletílico/metabolismo
17.
An. acad. bras. ciênc ; 89(3,supl): 2033-2041, 2017. tab, graf
Artigo em Inglês | LILACS | ID: biblio-886795

RESUMO

ABSTRACT The effect on different three carbon source (i.e. glucose, fructose and sucrose) on production, chemical characterization and antioxidant activity of exopolysaccharide (EPS) produced by Phellinus vaninii Ljup was investigated in this study. Amongst carbon sources examined, glucose and sucrose were favorable for the mycelia growth, while the maximum EPS yield was achieved when sucrose was employed. The predominant carbohydrate compositions in EPSs identified were gluconic acid, glucose, mannose and galactose acid. Then, FT-IR spectral analysis revealed prominent characteristic groups in EPSs. EPSs molecule exist as nearly globular shape form in aqueous solution. The variation also affects antioxidant activities by investigated by using hydroxyl and DPPH radical scavenging assay. Sucrose was best carbon source from the viewpoint of antioxidant activity due to the relatively high contents of galactose in the EPS with moderate molecular weight and polydispersity.


Assuntos
Polissacarídeos Bacterianos/metabolismo , Carbono/metabolismo , Polissacarídeos Fúngicos , Sacarose/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier , Frutose/metabolismo , Glucose/metabolismo
18.
Food Technol Biotechnol ; 54(3): 290-295, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27956860

RESUMO

In this study, the effects of the addition of Tween 80 and acetone on secretion, structure and antioxidant activities of Lentinus tigrinus exopolysaccharides (EPS) were investigated. It was found that Tween 80 and acetone displayed a stimulatory effect on EPS secretion. The EPS obtained by the addition of Tween 80 (EPS-T), acetone (EPS-A) and control (EPS--C) were purified by Sepharose CL-6B gel filtration chromatography and molecular mass of purified fractions was estimated to be 22.1, 137 and 12 kDa, respectively. Monosaccharide composition analysis indicated that EPS-T, EPS-A and EPS-C were mainly composed of glucose and mannose. Congo Red test indicated that EPS-T and EPS-A had a highly ordered conformation of triple helix, while EPS-C had a random coil conformation. Furthermore, EPS-A exhibited higher DPPH scavenging and antiproliferative activities than EPS--C and EPS-T, which might be attributed to the molecular mass.

19.
Molecules ; 21(7)2016 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-27420042

RESUMO

The aim of this study was to develop an ionic liquid (IL) system for the enzymatic resolution of racemic ibuprofen ethyl ester to produce (S)-ibuprofen. Nineteen ILs were selected for use in buffer systems to investigate the effects of ILs as cosolvents for the production of (S)-ibuprofen using thermostable esterase (EST10) from Thermotoga maritima. Analysis of the catalytic efficiency and conformation of EST10 showed that [OmPy][BF4] was the best medium for the EST10-catalyzed production of (S)-ibuprofen. The maximum degree of conversion degree (47.4%), enantiomeric excess of (S)-ibuprofen (96.6%) and enantiomeric ratio of EST10 (177.0) were achieved with an EST10 concentration of 15 mg/mL, racemic ibuprofen ethyl ester concentration of 150 mM, at 75 °C , with a reaction time of 10 h. The reaction time needed to achieve the highest yield of (S)-ibuprofen was decreased from 24 h to 10 h. These results are relevant to the proposed application of ILs as solvents for the EST10-catalyzed production of (S)-ibuprofen.


Assuntos
Etil-Éteres/química , Ibuprofeno/química , Líquidos Iônicos/química , Solventes/química , Catálise , Concentração de Íons de Hidrogênio , Hidrólise , Conformação Molecular , Temperatura
20.
Biotechnol Lett ; 37(10): 1993-8, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26026965

RESUMO

OBJECTIVES: A novel ß-carotene-9,10'-oxygenase (ScBCO2) has been characterized from Saccharomyces cerevisiae ULI3 to convert ß-carotene to ß-apo-10'-carotenal, which is a precursor of the plant hormone strigolactone. RESULTS: The ScBCO2 enzyme was purified to homogeneity by ammonium sulfate precipitation, Q sepharose and Superdex-200 chromatography. The molecular mass of the enzyme was ~50 kDa by SDS-PAGE. The purified ScBCO2 enzyme displayed optimal activity at 45 °C and pH 8. Tween 20 (1%, w/v), Trition X-100 (1%, w/v), Mg(2+) (5 mM), Zn(2+) (5 mM), Cu(2+) (5 mM), Ca(2+) (5 mM) or DTT (5 mM) increased in the activity by 3, 7, 14, 17, 23, 26 and 27%, respectively. ScBCO2 only exhibited cleavage activity towards carotenoid substrates containing two ß-ionone rings and its catalytic efficiency (kcat/Km) followed the order ß-carotene > α-carotene > lutein. CONCLUSION: ScBCO2 could be used as a potential candidate for the enzymatic biotransformation of ß-carotene to ß-apo-10'-carotenal in biotechnological applications.


Assuntos
Carotenoides/metabolismo , Dioxigenases/isolamento & purificação , Dioxigenases/metabolismo , Proteínas de Saccharomyces cerevisiae/isolamento & purificação , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/enzimologia , beta Caroteno/metabolismo , Precipitação Química , Cromatografia Líquida , Dioxigenases/química , Ativadores de Enzimas/análise , Humanos , Concentração de Íons de Hidrogênio , Recém-Nascido , Peso Molecular , Oxirredução , Proteínas de Saccharomyces cerevisiae/química , Especificidade por Substrato , Temperatura
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