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1.
Food Chem ; 305: 125438, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31494498

RESUMO

Fifteen vitisin A-type pyranoanthocyanins (vAPs) were determined in bilberry wines fermented with Saccharomyces cerevisiae and Schizosaccharomyces pombe by HPLC-DAD and UPLC-DAD-ESI-MS/MS. The fermentation involving S. pombe enhanced the production of vAPs compared to the fermentation with pure S. cerevisiae. The formation of vAPs correlated significantly with the decrease in the content of monomeric anthocyanins and pyruvic acid during 12 months of aging. vAPs were more stable than their corresponding monomeric anthocyanins. Methylation in the B-ring and glycosylation with galactose and arabinose further improved the stability of vAPs. Aging for 12 months led to depletion of pyruvic acid and reduction of over 50% of monomeric anthocyanins. The content of vAPs increased by 26-54% during the first six months of aging, followed by a 2.2-10.2% reduction over the following six months. More residual pyruvic acid in S. pombe wines after fermentation consequently enhanced the generation of vAPs during aging.

2.
ACS Synth Biol ; 8(5): 1037-1046, 2019 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-30990999

RESUMO

Large hydrophobic molecules, such as carotenoids, cannot be effectively excreted from cells by natural transportation systems. These products accumulate inside the cells and affect normal cellular physiological functions, which hinders further improvement of carotenoid production by microbial cell factories. In this study, we proposed to construct a novel artificial transport system utilizing membrane lipids to carry and transport hydrophobic molecules. Membrane lipids allow the physiological mechanism of membrane dispersion to be reconstructed and amplified to establish a novel artificial membrane vesicle transport system (AMVTS). Specifically, a few proteins in E. coli were reported or proposed to be related to the formation mechanism of outer membrane vesicles, and were individually knocked out or overexpressed to test their physiological functions. The effects on tolR and nlpI were the most significant. Knocking out both tolR and nlpI resulted in a 13.7% increase of secreted ß-carotene with a 35.6% increase of specific production. To supplement the loss of membrane components of the cells due to the increased membrane vesicle dispersion, the synthesis pathway of phosphatidylethanolamine was engineered. While overexpression of AccABCD and PlsBC in TW-013 led to 15% and 17% increases of secreted ß-carotene, respectively, the overexpression of both had a synergistic effect and caused a 53-fold increase of secreted ß-carotene, from 0.2 to 10.7 mg/g dry cell weight (DCW). At the same time, the specific production of ß-carotene increased from 6.9 to 21.9 mg/g DCW, a 3.2-fold increase. The AMVTS was also applied to a ß-carotene hyperproducing strain, CAR025, which led to a 24-fold increase of secreted ß-carotene, from 0.5 to 12.7 mg/g DCW, and a 61% increase of the specific production, from 27.7 to 44.8 mg/g DCW in shake flask fermentation. The AMVTS built in this study establishes a novel artificial transport mechanism different from natural protein-based cellular transport systems, which has great potential to be applied to various cell factories for the excretion of a wide range of hydrophobic compounds.

3.
J Chromatogr B Analyt Technol Biomed Life Sci ; 1114-1115: 100-109, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30947130

RESUMO

The purpose of this study was to find the component of the Bifidobacterium cell wall more particularly the functional groups from peptidoglycan involved in the mechanism of binding with Benzo[a]pyrene. Additionally, the effect of different stress factors (acid, heat, alkaline, oxidative, osmotic, enzymatic, and detergent factors) on the functional group and the overall binding mechanism of Bifidobacterium with B[a]p were also evaluated. Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) were used to explain the binding mechanism of Bifidobacterium with B[a]p along with HPLC (high-performance liquid chromatography). The peptidoglycan-B[a]p complexes were highly stable after benzene washing. Peptidoglycan from Bifidobacterium infantis BY12 showed highest binding rate with B[a]p out of nine selected strains. FTIR spectra showed that the main functional groups involved in B[a]p binding were CO, OH and/or NH. FTIR spectrums along with SEM electrographs as a function of stress factors reveal that peptidoglycan structural integrity is important in B[a]p binding. Bifidobacterium longum subsp. infantis BY12 may be employed as a biological detoxification agent for the elimination of B[a]p from human diet and animal feed in the future.


Assuntos
Benzo(a)pireno/metabolismo , Bifidobacterium/citologia , Bifidobacterium/metabolismo , Peptidoglicano/metabolismo , Benzo(a)pireno/análise , Bifidobacterium/química , Bifidobacterium/fisiologia , Peptidoglicano/química , Probióticos , Espectroscopia de Infravermelho com Transformada de Fourier , Estresse Fisiológico
4.
Int J Biol Macromol ; 133: 674-682, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31022485

RESUMO

In the current study, a carboxyl-rich polysaccharide purified from Lycium barbarum L. leaves (hereafter, LP) and its degradation with ascorbic acid and hydrogen peroxide were characterized. Degradation decreased the molecular weight of LP from 4.63 × 104 to 3.45 × 104 Da, and increased its zeta potential from -8.01 to -5.35 mV. In vitro experiments showed that degradation significantly increased the anticoagulant activity and, in particular, antiplatelet activity of LP (p < 0.05). The polysaccharide with the highest degree of degradation had higher inhibitory activity than aspirin against arachidonic acid- and thrombin-induced platelet aggregation at 0.5 g/mL. A reduction in uronic acids between LP and its degradation products significantly decreased their antiplatelet activity (p < 0.05). Further analysis confirmed that polysaccharides changed from a compact spherical structure to a random coil in aqueous solution following degradation, which facilitated the interaction of polysaccharides and platelets.


Assuntos
Lycium/química , Folhas de Planta/química , Polissacarídeos/química , Polissacarídeos/farmacologia , Anticoagulantes/química , Anticoagulantes/farmacologia , Ácido Ascórbico/química , Configuração de Carboidratos , Frutas/química , Humanos , Peróxido de Hidrogênio/química , Peso Molecular , Inibidores da Agregação de Plaquetas/química , Inibidores da Agregação de Plaquetas/farmacologia
5.
Nutrients ; 11(2)2019 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-30720717

RESUMO

Schisandra chinensis (Turcz.) Baill. (SCE) is a plant with high potential for beneficial health effects, confirmed by molecular studies. Its constituents exert anti-cancer effects through the induction of cell cycle arrest and apoptosis, as well as inhibition of invasion and metastasis in cancer cell lines and experimental animals. SCE displays antimicrobial effects against several pathogenic strains. It has anti-diabetic potential, supported by hypoglycemic activity. A diet rich in SCE improves pancreatic functions, stimulates insulin secretion, and reduces complications in diabetic animals. SCE prevents lipid accumulation and differentiation of preadipocytes, indicating its anti-obesity potential. SCE exerts a protective effect against skin photoaging, osteoarthritis, sarcopenia, senescence, and mitochondrial dysfunction, and improves physical endurance and cognitive/behavioural functions, which can be linked with its general anti-aging potency. In food technology, SCE is applied as a preservative, and as an additive to increase the flavour, taste, and nutritional value of food. In summary, SCE displays a variety of beneficial health effects, with no side effects. Further research is needed to determine the molecular mechanisms of SCE action. First, the constituents responsible for its beneficial effects should be isolated and identified, and recommended as preventative nutritional additives, or considered as therapeutics.


Assuntos
Preparações de Plantas/farmacologia , Schisandra , Animais , Anti-Infecciosos/farmacologia , Fármacos Antiobesidade/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Conservantes de Alimentos , Humanos , Fitoterapia/métodos , Substâncias Protetoras/farmacologia
6.
J Sci Food Agric ; 2018 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-30506690

RESUMO

BACKGROUND: Peptides can act as antioxidants in emulsion but the mechanism is poorly understood. Caragana ambigua seed is a potential protein source, the commercial applications of which have not been explored yet. Here we aimed to evaluate the bio-economic potential of C. ambigua by isolating and characterizing antioxidative peptides from its seeds' protein hydrolysate for the purpose of protecting lipids from oxidation. RESULTS: A novel decapeptide, identified as QITEGEDGGG, was purified by HPLC based on enrichment of antioxidant fractions, and its antioxidative activity for walnut oil was evaluated in terms of its effect on oil quality, primary and secondary peroxide formation, oxidation kinetics, and structure of oil droplets. A molecular simulation involving the peptide and fatty acid was carried out to understand the mechanism underlying the prevention of lipid oxidation by the peptide. The peptide effectively scavenged superoxide anions (86.46%), inhibited the rate of linoleic acid oxidation (60.37%), and delayed auto-oxidation of walnut oil. Its inhibition of lipid oxidation was attributed to the protection of phenolic compounds and polyunsaturated fatty acids of walnut oil. CONCLUSION: Our findings will help exploit novel antioxidant peptides of lipids from woody seed-based protein sources such the seeds of C. ambigua trees. This article is protected by copyright. All rights reserved.

7.
Int J Biol Macromol ; 123: 182-188, 2018 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-30445070

RESUMO

A heteropolysaccharide, LP5, was purified from Lycium barbarum L. leaves. It was identified as a calcium-rich polysaccharide (8.6 mg calcium/g) with a molecular weight of 2.50 × 105 Da. The polysaccharide was composed of six kinds of monosaccharides, of which mannose and xylose are the main components. And it contains 16.37% glucuronic acid. Studies on RAW264.7 cells demonstrated that this polysaccharide exhibited potent immunomodulatory activity, including an increase in phagocytic activity, as well as the release of both nitric oxide and cytokines. However, after the depletion of calcium, the polysaccharide exhibited greater immunomodulatory activity (p < 0.05). Further conformation analysis confirmed that the polysaccharide changed from a compact spherical conformation to a random coil structure in aqueous solution after the depletion of calcium, which resulted in increased immunomodulatory activity by LP5.

8.
J Food Sci Technol ; 55(6): 2240-2250, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29892124

RESUMO

This study aimed to investigate the effect of Lactobacillus plantarum strains on quality improvement of bog bilberry juice. Bog bilberry juice with different pH conditions was fermented by Lactobacillus B7 or C8-1 strain. Physicochemical index, amino acids, phenolic compounds, and volatiles of these fermented juices were compared. Results indicated that Lactobacillus plantarum strains preferred to metabolize malic acid and reducing sugar in non-pH-adjusted juice (NJ, pH 2.65), whereas quinic and citric acids were largely consumed in pH-adjusted juice (AJ, pH 3.50). Shikimic acid and aromatic amino acids were significantly accumulated in pH-adjusted juice, and phenolic compounds in both juices were significantly reduced. These strains enhanced the composition and concentration of volatiles compounds in non-pH-adjusted juice and improved the floral and fruity flavors. However, concentration and complexity of volatiles were reduced in pH-adjusted juices.

9.
Sheng Wu Gong Cheng Xue Bao ; 34(5): 703-711, 2018 May 25.
Artigo em Chinês | MEDLINE | ID: mdl-29893078

RESUMO

Carotenoids are a class of terpenes of commercial interest and exert important biological functions. Engineering morphological and biosynthetic aspects of Escherichia coli cell membrane could improve its storage capacity for ß-carotene. However, how the synthesis of phosphatidylethanolamine, the major component of the cell membrane, was not discussed in detail. In this work, the synthesis of phosphatidylethanolamine was divided into three modules to discuss their synergetic effect, by expressing in different combinations. Overexpressing the upstream module 1 in CAR016 caused a 30.5% increase of ß-carotene specific production (from 10.1 mg/g to 13.7 mg/g DCW); combined overexpressing module 1 and module 2 in CAR016 led to a 122% increase of ß-carotene specific production (from 10.5 mg/g to 22.3 mg/g DCW). The optimal expression combination of the phosphatidylethanolamine synthetic pathway was obtained, which further increased the content of the cell membrane for ß-carotene storage, and improved its production. The membrane engineering strategy opens up a new direction for engineering microbial producers for a large spectrum of hydrophobic molecules.

10.
Front Microbiol ; 9: 1194, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29922266

RESUMO

Lactobacillus helveticus is an important lactic acid bacterium. The strains used in this study have proven probiotic function, and the potential to produce functional dairy products and bioactive peptides. To explore the effects of vitamins on the growth of L. helveticus, a chemically defined medium was designed and nine vitamins were tested. Pantothenic acid (Vb5), vitamin C (Vc), and biotin were necessary for the growth of L. helveticus CICC 22171. These three vitamins had an important effect on the glucose metabolism and energy metabolism of strain CICC 22171. Through transcriptomic analysis, we found that three vitamins were related to the synthesis of fatty acids and participate in the energy supply of the cells. Additionally, Vb5 was involved in the metabolism of bacterial proteins and lipids and was related to the activity of various enzymes. The results indicated that Vc was involved in protein metabolism, and biotin affected the intracellular transport mechanism of bacteria. The ability of vitamins to promote the growth of the strain was verified in skim milk medium. The results indicated that Vc, biotin, and Vb5 could promote the proliferation of L. helveticus but had no significant effect on Lactobacillus bulgaricus.

11.
Data Brief ; 17: 926-937, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29876448

RESUMO

The data investigated 198 volatile compounds of six currant cultivars grown in China which is analyzed by SPME-GC-MS. Volatile compounds in these currant samples were identified by two methods, comparing retention indices with reference standards and matching mass spectrum in the NST11 library. A synthetic currant matrix prepared according to the currant juice condition were extracted and analyzed using the same extraction procedure as the currant samples. The standard curve was generated for quantification of volatile compounds. For the volatiles without the available standard, the data provided consulting standards that had the same carbon atom or the similar functional structure for quantification. Further interpretation and discussion can be seen in article entitled "Characterization of Free and Bound Volatile Compounds in Six Ribes nigrum L. Blackcurrant Cultivars" (Liu et al., 2018) [1].

12.
Microb Cell Fact ; 17(1): 85, 2018 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-29866124

RESUMO

BACKGROUND: Geranyl acetate is widely used in the fragrance and cosmetic industries, and thus has great economic value. However, plants naturally produce a mixture of hundreds of esters, and geranyl acetate is usually only present in trace amounts, which makes its economical extraction from plant sources practically impossible. As an ideal host for heterologous production of fragrance compound, the Saccharomyces cerevisiae has never been engineered to produce the esters, such as geranyl acetate. RESULTS: In this study, a heterologous geranyl acetate synthesis pathway was constructed in S. cerevisiae for the first time, and a titer of 0.63 mg/L geranyl acetate was achieved. By expressing an Erg20 mutant to divert carbon flux from FPP to GPP, the geranyl acetate production increased to 2.64 mg/L. However, the expression of heterologous GPP had limited effect. The highest production of 13.27 mg/L geranyl acetate was achieved by additional integration and expression of tHMG1, IDI1 and MAF1. Furthermore, through optimizing fermentation conditions, the geranyl acetate titer increased to 22.49 mg/L. CONCLUSIONS: We constructed a monoterpene ester producing cell factory in S. cerevisiae for the first time, and demonstrated the great potential of this system for the heterologous production of a large group of economically important fragrance compounds.


Assuntos
Acetatos/metabolismo , Ésteres/metabolismo , Monoterpenos/metabolismo , Saccharomyces cerevisiae/patogenicidade , Terpenos/metabolismo , Engenharia Tecidual/métodos
13.
Front Microbiol ; 9: 1034, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29867910

RESUMO

Lycium barbarum is a boxthorn that produces the goji berries. The aim of the current study was to evaluate the proliferative effect of L. barbarum polysaccharides (LBP) on probiotics. LBP was extracted from goji berries and its monosaccharide composition characterized by gas chromatography (GC). The LBP extract contained arabinose, rhamnose, xylose, mannose, galactose, and glucose. LBP obviously promoted the proliferation of lactic acid bacteria (LAB) strains, especially Bifidobacterium longum subsp. infantis Bi-26 and Lactobacillus acidophilus NCFM. In the presence of LBP in the growth medium, the ß-galactosidase (ß-GAL) and lactate dehydrogenase (LDH) activities of strain Bi-26 significantly increased. The activities of ß-GAL, LDH, hexokinase (HK), 6-phosphofructokinase (PFK), and pyruvate kinase (PK) of strain NCFM significantly increased under those conditions. LAB transcriptome sequencing analysis was performed to elucidate the mechanism responsible for the proliferative effect of LBP. The data revealed that LBP promoted the bacterial biosynthetic and metabolic processes, gene expression, transcription, and transmembrane transport. Pyruvate metabolism, carbon metabolism, phosphotransferase system (PTS), and glycolysis/gluconeogenesis genes were overexpressed. Furthermore, LBP improved cell vitality during freeze-drying and tolerance of the gastrointestinal environment. In summary, LBP can be used as a potential prebiotic for Bifidobacterium and Lactobacillus.

14.
3 Biotech ; 8(6): 269, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29868307

RESUMO

The goal of this work was to improve the lycopene storage capacity of the E. coli membrane by engineering both morphological and biosynthetic aspects. First, Almgs, a protein from Acholeplasma laidlawii that is involved in membrane bending is overexpressed to expand the storage space for lycopene, which resulted in a 12% increase of specific lycopene production. Second, several genes related to the membrane-synthesis pathway in E. coli, including plsb, plsc, and dgka, were also overexpressed, which led to a further 13% increase. In addition, membrane separation and component analysis confirmed that the increased amount of lycopene was mainly accumulated within the cell membranes. Finally, by integrating both aforementioned modification strategies, a synergistic effect could be observed which caused a 1.32-fold increase of specific lycopene production, from the 27.5 mg/g of the parent to 36.4 mg/g DCW in the engineered strain. This work demonstrates that membrane engineering is a feasible strategy for increasing the production and accumulation of lycopene in E. coli.

15.
Food Res Int ; 108: 254-263, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29735055

RESUMO

This study investigated the evolution of acetaldehyde and pyranoanthocyanins in wine during malolactic fermentation, and further evaluated the correlation between acetaldehyde and pyranoanthocyanins. Cabernet Gernischt wine after alcoholic fermentation was inoculated with four lactic acid bacteria strains. Malolactic fermentation kinetics and wine characteristics were compared. Results showed these strains exhibited different kinetics on wine malolactic fermentation. Wine with Lactobacillus plantarum had lower reducing sugar, total acid, and yellowness. Lactobacillus plantarum elevated the level of acetaldehyde in wine model medium and wine during malolactic fermentation. Malolactic fermentation using Lactobacillus plantarum significantly increased the concentration of pyranoanthocyanins, whereas O. oeni strain reduced the level of pyranoanthocyanins in wine. Polymerized anthocyanins percentage in wine was significantly enhanced after fermentation with Lactobacillus plantarum. Principal component analysis indicated that the characteristics of these strains inoculated wines after malolactic fermentation were segregated. The findings from this study could provide useful information on the wine color improvement through malolactic fermentation with suitable lactic acid bacteria strains.

16.
Food Res Int ; 107: 509-517, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29580514

RESUMO

The objectives of this study were to evaluate the role of sucrose on the stability of anthocyanins during heating and the anticancer effects of anthocyanins/anthocyanidins on HepG-2 cells. The anthocyanins extract was heated at 70 °C, 100 °C, and 120 °C in the presence of 5%, 10%, and 20% sucrose. Total anthocyanin content, anthocyanin/anthocyanidin species, and the ability to induce HepG-2 cell apoptosis were evaluated. The results indicated that the total anthocyanin content decreased during heating at temperatures above 70 °C. Anthocyanins were degraded into anthocyanidins after heat treatment and the degradation rate positively correlated with temperature. The degradation of anthocyanins was inhibited with the addition 5% to 20% sucrose. However, sucrose had no protective effect on the total anthocyanin content. The anticancer ability of blueberry extract was assayed using HepG-2 cells and found to be associated with the concentration of anthocyanins. Anthocyanins displayed stronger anticancer activity than anthocyanidins and this has not been reported so far.

17.
Food Res Int ; 103: 301-315, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29389620

RESUMO

This study investigated the profiles of free and bound volatile compounds of six currant cultivars grown in China. Results showed that 166 free and 111 bound volatiles were found in these cultivars with esters and terpenoids as the major volatiles. Additionally, 10 hydroxy esters were detected in these cultivars for the first time. Floral, fruity, and sweet flavors appeared to be the feature aroma in these cultivars, which resulted from the contribution of 17 volatiles. Principal component analysis indicated the cultivar "Fertodi", "Risagar" and "Liangye" had the similar profiles of free and bound volatile compounds, whereas the cultivar "Brodtrop" and "Yadrionaya" exhibited the similarity on their free and bound volatiles. The cultivar "Sofya" showed a different volatile composition. Cluster analysis revealed the cultivar "Fertodi", "Risagar", and "Liangye" had the similar profiles of free and bound volatile compounds, whereas the similar free and bound volatile compositions were observed in the cultivar "Sofya" and "Yadrionaya". This study could provide useful information on quality control of commercial currant products.

18.
Waste Manag ; 73: 101-112, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29279244

RESUMO

A comprehensive characterization of the bacterial diversity associated to thermophilic stages of green waste composting was achieved. In this study, eight different treatments (T1-T8) and three replicated lab-scale green waste composting were carried out to compare the effect of the cellulase (i.e. 0, 2%), microbial inoculum (i.e. 0, 2 and 4%) and particle size (i.e. 2 and 5 mm) on bacterial community structure. Physicochemical properties and bacterial communities of T1-T8 composts were observed, and the bacterial structure and diversity were examined by high-throughput sequencing via a MiSeq platform. The results showed that the most abundant phyla among the treatments were the Firmicutes, Chloroflexi and Proteobacteria. The shannon index and non-metric multidimensional scaling (NMDS) showed higher bacterial abundance and diversity at the metaphase of composting. Comparing with 5-mm treatments, particle size of 2-mm had a richer diversity of bacterial communities. The addition of cellulase and a microbial inoculum could promote the fermentation temperature, reduce the compost pH and C/N ratio and result in higher GI index. The humic substance (HS) and humic acid (HA) contents for 2-mm particle size treatments were higher than those of 5-mm treatments. Canonical correspondence analysis suggested that differences in bacterial abundance and diversity significantly correlated with HA, E4/E6 and temperature, and the relationship between bacterial diversity and environmental parameters was affected by composting stages. Based on these results, the application of cellulase to promote green waste composting was feasible, and particle size was identified as a potential control of composting physicochemical properties and bacterial diversity.


Assuntos
Compostagem , Microbiologia do Solo , Bactérias , Substâncias Húmicas , Solo , Temperatura Ambiente
19.
Metab Eng ; 43(Pt A): 85-91, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28688931

RESUMO

Carotenoids are a class of terpenes of commercial interest that exert important biological functions. While various strategies have been applied to engineer ß-carotene production in microbial cell factories, no work has been done to study and improve the storage of hydrophobic terpene products inside the heterologous host cells. Although the membrane is thought to be the cell compartment that accumulates hydrophobic terpenes such as ß-carotene, direct evidence is still lacking. In this work, we engineered the membrane of Escherichia coli in both its morphological and biosynthetic aspects, as a means to study and improve its storage capacity for ß-carotene. Engineering the membrane morphology by overexpressing membrane-bending proteins resulted in a 28% increase of ß-carotene specific producton value, while engineering the membrane synthesis pathway led to a 43% increase. Moreover, the combination of these two strategies had a synergistic effect, which caused a 2.9-fold increase of ß-carotene specific production value (from 6.7 to 19.6mg/g DCW). Inward membrane stacks were observed in electron microscopy images of the engineered E. coli cells, which indicated that morphological changes were associated with the increased ß-carotene storage capacity. Finally, membrane separation and analysis confirmed that the increased ß-carotene was mainly accumulated within the cell membrane. This membrane engineering strategy was also applied to the ß-carotene hyperproducing strain CAR025, which led to a 39% increase of the already high ß-carotene specific production value (from 31.8 to 44.2mg/g DCW in shake flasks), resulting in one of the highest reported specific production values under comparable culture conditions. The membrane engineering strategy developed in this work opens up a new direction for engineering and improving microbial terpene producers. It is quite possible that a wide range of strains used to produce hydrophobic compounds can be further improved using this novel engineering strategy.


Assuntos
Membrana Celular/metabolismo , Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Engenharia Genética , Proteínas de Membrana/metabolismo , beta Caroteno/biossíntese , Membrana Celular/genética , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Proteínas de Membrana/genética , beta Caroteno/genética
20.
World J Microbiol Biotechnol ; 33(8): 156, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28702797

RESUMO

Vibrio parahaemolyticus: is recognized as the main cause of gastroenteritis associated with consumption of seafood. Bacteriocin-producing Lactobacillus plantarum FGC-12 isolated from golden carp intestine had strong antibacterial activity toward V. parahaemolyticus. The fish-borne bacteriocin was purified by a three-step procedure consisting of ethyl acetate extraction, gel filtration chromatography and high performance liquid chromatography. Its molecular weight was estimated at 4.1 kDa using SDS-PAGE. The fish-borne bacteriocin reached the maximum production at stationary phase after 20 h. It was heat-stable (30 min at 121 °C) and remained active at pH range from 3.0 to 5.5, but was sensitive to nutrasin, papain and pepsin. Its minimum inhibitory concentration for V. parahaemolyticus was 6.0 mg/ml. Scanning electron microscopy analysis showed that the fish-borne bacteriocin disrupted cell wall of V. parahaemolyticus. The antibacterial mechanism of the fish-borne bacteriocin against V. parahaemolyticus might be described as action on membrane integrity in terms of the leakage of electrolytes, the losses of Na+K+-ATPase, AKP and proteins. The addition of the fish-borne bacteriocin to shrimps leaded V. parahaemolyticus to reduce 1.3 log units at 4 °C storage for 6 day. Moreover, a marked decline in total volatile base nitrogen and total viable counts was observed in bacteriocin treated samples than the control. It is clear that this fish-borne bacteriocin has promising potential as biopreservation for the control of V. parahaemolyticus in aquatic products.


Assuntos
Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Bacteriocinas/isolamento & purificação , Bacteriocinas/farmacologia , Peixes/microbiologia , Lactobacillus plantarum/metabolismo , Penaeidae/microbiologia , Vibrio parahaemolyticus/efeitos dos fármacos , Adenosina Trifosfatases/metabolismo , Animais , Antibacterianos/biossíntese , Antibacterianos/química , Bacteriocinas/biossíntese , Bacteriocinas/química , Permeabilidade da Membrana Celular/efeitos dos fármacos , Parede Celular/efeitos dos fármacos , Contagem de Colônia Microbiana , Eletrólitos , Microbiologia de Alimentos , Conservação de Alimentos , Armazenamento de Alimentos , Concentração de Íons de Hidrogênio , Lactobacillus plantarum/isolamento & purificação , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Varredura , Peso Molecular , Papaína , Pepsina A , Potássio/metabolismo , Alimentos Marinhos , Sódio/metabolismo , Temperatura Ambiente , Vibrio parahaemolyticus/citologia , Vibrio parahaemolyticus/patogenicidade , Microbiologia da Água
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