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1.
Food Chem ; 305: 125439, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31499287

RESUMO

Compared to the control longans, hydrogen peroxide (H2O2)-treated longans exhibited higher index of pulp breakdown, higher fruit respiration rate, higher activities of pulp phosphohexose isomerase (PGI), succinate dehydrogenase (SDH), cytochrome C oxidase (CCO), ascorbic acid oxidase (AAO) and polyphenol oxidase (PPO), but lower activity of pulp nicotinamide adenine dinucleotide kinase (NADK). H2O2-treated longans also exhibited lower total activities of pulp glucose-6-phosphate dehydrogenase (G-6-PDH) and 6-phosphogluconate dehydrogenase (6-PGDH), lower levels of pulp NADP(H), but higher levels of pulp NAD(H). These data indicated that H2O2-stimulated longan pulp breakdown was owing to a decreased proportion of pentose phosphate pathway (PPP), the increased proportions of Embden-Meyerhof-Parnas pathway (EMP), tricarboxylic acid (TCA) cycle and cytochrome pathway (CCP) in total respiratory pathways. These findings further revealed that H2O2 could enhance respiration rate, and thus accelerate pulp breakdown occurrence and shorten the shelf life of longan fruit.

2.
Food Chem ; 306: 125627, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31610328

RESUMO

Effects of various concentrations of Kadozan (chitosan) treatment on storability and quality properties of harvested 'Fuyan' longans were investigated. Compared to the control samples, Kadozan treated-longans displayed lower fruit respiration rate, lower pericarp cell membrane permeability, pericarp browning index, pulp breakdown index, fruit disease index, and weight loss, but higher rate of commercially acceptable fruit, higher levels of pericarp chlorophyll, carotenoid, anthocyanin, flavonoid and total phenolics, higher amounts of pulp total soluble sugar, sucrose, total soluble solids, and vitamin C. These results revealed Kadozan treatment could increase storability and retain better quality of harvested longan fruit. Among different concentrations of Kadozan, the dilution of 1:500 (VKadozan: VKadozan + Water) showed the best results in storability and maintained the best quality of longans during storage. These findings demonstrated that Kadozan could be a facile and eco-friendly postharvest handling approach for increasing storability and lengthening shelf-life of harvested 'Fuyan' longan fruit.

3.
Int J Biol Macromol ; 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31759007

RESUMO

The aims of this work were to synthesize cellulose nanofibril/titanium dioxide nanoparticle (CNF/TiO2NP) nanocomposites, evaluate the use of CNF/TiO2NP nanocomposites in PVA-based films, and investigate the intestinal toxicity of the nanocomposites. Via a mixing method, CNF/TiO2NP nanocomposites were synthesized. The addition of the nanocomposites significantly enhanced the tensile strength, Young's modulus, and light barrier capacity of PVA films. Moreover, a high concentration of CNF/TiO2NP nanocomposites (10 mg/mL) had no appreciable effect on the growth of Escherichia coli P-24, Lactobacillus acidophilus ADH, and Bifidobacterium animalis Bif-6 cells. The nanocomposites did not exhibit significant toxicity to cancerous and normal colon cells even when their concentrations increased to a high level of 1000 µg/mL. The results indicate that CNF/TiO2NP nanocomposites can potentially be used as functional fillers for a PVA-based packaging system.

4.
Analyst ; 144(16): 4820-4825, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31282496

RESUMO

Rapid detection of food contaminants using novel analytical methods in combination with nanomaterials has received much attention. This study aimed to synthesize polyhedral gold nanostars (AuNS) with multi-angled corners and develop a surface-enhanced Raman spectroscopy (SERS) method coupled with AuNS to detect pesticide residues in juice products. AuNS are multi-branched three-dimensional metal nanostructures with rough surface features which can induce surface plasmon resonance. A facile synthesis of AuNS was achieved using a two-step method and as-prepared AuNS had much cleaner surfaces than gold nanoparticles. A Raman reporter molecule (4-aminothiophenol) was used to evaluate the performance of the SERS method, yielding fingerprint-like Raman spectra and the sensitivity of the SERS method could reach 10 ppb (µg kg-1). SERS coupled with AuNS was used to detect thiram residues in peach juice and the detection limit was 50 ppb, and is 100 times more sensitive than using normal gold nanoparticles. These results demonstrate that AuNS are excellent substrates for SERS measurement, which has great potential for rapid detection of chemical contaminants in food products.

5.
Food Chem ; 293: 271-277, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31151611

RESUMO

The contamination of pesticide residues in Oolong tea has raised much concern in recent years. The objective of this study was to synthesize gold nanoparticles (AuNPs) and develop surface-enhanced Raman spectroscopy (SERS) methods for detection and quantification of pesticides in Oolong tea. Facile synthesis of spherical and monodispersed AuNPs with an average diameter of 15 nm was achieved, which induced strong electromagnetic fields in SERS analysis. AuNP substrates were employed for rapid detection and quantification of carbendazim in Tieguanyin Oolong tea. Partial least squares (PLS) analysis and leave-one-out cross validation were utilized in spectral data analysis. The PLS results for Oolong tea samples were obtained: R value = 0.964; the detection limit = 100 µg/kg. These results demonstrate that SERS coupled with gold nanoparticle substrate is a simple, rapid, and sensitive analytical tool for measurement and quantification of carbendazim residues in Oolong tea.


Assuntos
Benzimidazóis/análise , Carbamatos/análise , Ouro/química , Nanopartículas Metálicas/química , Resíduos de Praguicidas/análise , Praguicidas/análise , Análise Espectral Raman/métodos , Chá/química , Cor , Limite de Detecção
6.
Mikrochim Acta ; 186(7): 453, 2019 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-31201539

RESUMO

The authors describe a three-dimensional (3D) flexible interconnected porous nanocomposite membrane for use in surface-enhanced Raman scattering (SERS). It was obtained via in -situ deposition of gold nanoparticles (AuNPs, ca. 10 nm) on eggshell membranes (ESM). The AuNP/ESM nanocomposites were used as a SERS substrate for detection of the pesticide thiabendazole (TBZ) with prominent Raman bands at 1180, 1280, and 1580 cm-1. The abundant "hot spots" are generated by the closely arranged AuNPs in the 3D geometry of the ESM networks. This makes the SERS substrate highly sensitive because of remarkable signal amplification. The substrates were applied to the rapid detection of TBZ in Oolong tea. The limit of detection for TBZ is 0.1 ppm. Graphical abstract Schematic presentation of a three-dimensional flexible interconnected porous nanocomposite membrane as surface-enhanced Raman scattering (SERS) substrate for detection of thiabendazole (TBZ) in tea.

7.
Food Chem ; 295: 311-319, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174763

RESUMO

A novel gene aga3027 from the genome of Flammeovirga sp. OC4, isolated from the deep sea, was screened and expressed in Escherichia coli BL21. This gene encoded the genetic information of a potential agarase that consists of 851 amino acids and belongs to 16 ß-agarase family of glycoside hydrolase. Purified recombinant Aga3027 demonstrated the maximum activity of agarase at 40 °C and pH 9.0, displaying excellent thermostability and pH-stability. The agarase retained more than 80% of its maximum activity after incubation at 30-40 °C for 48 h, or after incubation at pH 6.0-9.0 for 60 min, which indicated that this agarase was suitable for industrial applications. Silica gel chromatography was used to purify the hydrolysates of agar treated by agarase from the recombinant Aga3027. The hydrolysates were identified as neoagarotetraose and neoagarohexaose by thin layer chromatography and further confirmed by ion chromatography.


Assuntos
Ágar/química , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/metabolismo , Ágar/metabolismo , Bacteroidetes/enzimologia , Bacteroidetes/genética , Cromatografia em Camada Delgada , Estabilidade Enzimática , Escherichia coli/genética , Escherichia coli/metabolismo , Galactosídeos/metabolismo , Glicosídeo Hidrolases/genética , Concentração de Íons de Hidrogênio , Hidrólise , Oligossacarídeos/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Temperatura Ambiente
8.
Carbohydr Polym ; 217: 126-134, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31079668

RESUMO

Longan pulp is an excellent source of polysaccharides and other nutrients that have many health benefits. However, longans is susceptible to pulp breakdown after harvest and loses its nutrition values. To solve this problem, this study aimed to study the effects of a novel chitosan, Kadozan, on pulp breakdown index, contents of pectin, cellulose and hemicelluloses, and activities of enzymes in longan pulp relating to disassembly of polysaccharides (XET, PE, PG, ß-Gal, and cellulase). The data illustrated that, compared to the control longans, chitosan-treated longans contained higher amounts of CWM, CSP, ISP, cellulose and hemicelluloses, but exhibited lower pulp breakdown index, lower activities of cell wall-disassembling enzymes, and contained lower WSP amount. These results suggested that Kadozan with a dilution of 1:500 (VKadozan: VKadozan + Water) could significantly decrease activities of disassembling-enzymes and depolymerization of polysaccharides in cell wall, and subsequently alleviate pulp breakdown and prolong storage-life of postharvest longans.


Assuntos
Parede Celular/efeitos dos fármacos , Quitosana/farmacologia , Inibidores Enzimáticos/farmacologia , Frutas/metabolismo , Polissacarídeos/metabolismo , Sapindaceae/metabolismo , Parede Celular/metabolismo , Celulose/metabolismo , Conservação de Alimentos/métodos , Qualidade dos Alimentos , Glicosídeo Hidrolases/antagonistas & inibidores , Hidrólise/efeitos dos fármacos , Pectinas/metabolismo
9.
Colloids Surf B Biointerfaces ; 180: 212-220, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31054461

RESUMO

The objective of this study was to synthesize a novel antimicrobial cellulose nanofibril/silver nanoparticle (CNF/AgNP) nanocomposite by an ultraviolet (UV) irradiation method and evaluate the toxicity of the nanocomposite to human colon cells. AgNPs coated on CNFs have an average size of ˜28 nm and exhibited a surface plasma resonance absorption peak at 402 nm. Coating AgNPs on CNFs interfered with the formation of intra-chain and inter-chain hydrogen bonds of cellulose. Moreover, the CNF/AgNP nanocomposite exhibited significant antimicrobial activities against two important food-borne pathogens, including Escherichia coli O157:H7 and Staphylococcus aureus. No apparent toxicity of the CNF/AgNP nanocomposite to Caco-2 and FHC human colon cells was observed, except when a high content of (≥500 µg/m L) of the nanocomposite was used for which a significant decrease of cell viability was observed. The nanocomposite's toxicity was related to the content, size, and surface charge of UV-synthesized AgNPs on CNFs. These results indicate that the antimicrobial CNF/AgNP nanocomposite prepared by UV irradiation method can be potentially used as an active filler applied in food packaging materials.

10.
Food Chem Toxicol ; 130: 253-261, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31103740

RESUMO

Compound K is a type of protopanaxadiol-type ginsenosides (PPDs) that has strong bioactivities due to fewer glycosyls. However, compound K is not present in raw and unprocessed ginseng. Some PPDs have the same structure with gypenosides, and could be obtained from Gynostemma pentaphyllum. The enzymolysis of PPD-type gypenosides of G. pentaphyllum by naringinase has been reported for the first time in this research. In addition, isolation and identification of enzymolysis end product, and the optimization of enzymolysis parameters were investigated. The results showed that compound K was produced from the enzymolysis of PPD-type gypenosides by naringinase, and could be isolated and purificated by HP-20 macroporous resin and C-18 column chromatography. The optimum enzymolysis conditions determined by the response surface methodology (RSM) are pH 4.1, 50 °C, and 71 h, with a yield of 65.44 ±â€¯4.52% for compound K. These results demonstrated that enzymolysis could be a promising method for producing compound K from the biotransformation of PPD-type gypenosides of G. pentaphyllum.


Assuntos
Ginsenosídeos/química , Ginsenosídeos/metabolismo , Cromatografia Líquida , Gynostemma/química , Modelos Químicos , Complexos Multienzimáticos/metabolismo , Extratos Vegetais/química , beta-Glucosidase/metabolismo
11.
Food Chem Toxicol ; 128: 89-96, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30946873

RESUMO

Defatted-sesame meal (DSM), a byproduct of sesame oil, has attracted considerable interest in the food industry because of its strong antioxidant activity. The aim of this study was to measure the content and distribution of lignans in DSM and evaluate their antioxidant activity after thermal processing and in vitro digestion. The results showed that the sesame lignans (SL) content and antioxidant activity were significantly influenced by the temperature and time during thermal preparation, and the maximum antioxidant potency composite index (ACI) was obtained after roasting the samples at 240 °C for 20 min. As sesame seed was processed with longer time and higher temperature, more pinoresinol diglucoside (PD) and sesamol were measured in DSM. According to the correlation matrix under thermal preparation, a significant contribution to the antioxidant potency of DSM was discovered. After in vitro digestion, the release amount of lignans increased by 19.6%, and the values of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and ACI gradually declined after digestion, with a 40% decrease in both the DPPH radical scavenging activity and the ACI from oral to intestinal phase. These results could be used to help improve the bioavailability of SL and obtaining high quality sesame byproducts.


Assuntos
Antioxidantes/farmacologia , Temperatura Alta , Sementes/metabolismo , Sesamum/embriologia , Disponibilidade Biológica , Compostos de Bifenilo/farmacologia , Hidrólise , Técnicas In Vitro , Lignanas/metabolismo , Lignanas/farmacologia , Modelos Biológicos , Picratos/farmacologia
12.
Food Chem ; 275: 239-245, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30724192

RESUMO

This study aimed to investigate the effects of Lasiodiplodia theobromae (Pat.) Griff. & Maubl (L. theobromae) inoculation on the energy status and activity of adenosine triphosphatase (ATPase) during L. theobromae-induced disease development and pericarp browning of harvested 'Fuyan' longan (Dimocarpus longan Lour. cv. Fuyan) fruit. The results showed that, compared to the control longans, L. theobromae-inoculated longans displayed higher indices of fruit disease and pericarp browning, lower pericarp ATP and ADP contents, higher AMP content, lower level of energy charge, as well as lower activities of Ca2+-ATPase, Mg2+-ATPase and H+-ATPase in membranes of plasma, vacuole, and mitochondria. These results indicated that the infection of L. theobromae reduced energy status and ATPase activities, caused ions disorder, damaged the integrity and function of the cell and organelles including vacuole and mitochondria in pericarp of longan fruit, which contributed to L. theobromae-promoted disease development and pericarp browning of harvested longan fruit during storage.


Assuntos
Adenosina Trifosfatases/metabolismo , Ascomicetos/patogenicidade , Doenças das Plantas/microbiologia , Sapindaceae/metabolismo , Sapindaceae/microbiologia , Difosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Metabolismo Energético , Frutas/metabolismo , Frutas/microbiologia , Mitocôndrias/metabolismo , Proteínas de Plantas/metabolismo , Vacúolos/metabolismo
13.
Int J Biol Macromol ; 129: 887-894, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30776442

RESUMO

Cellulose nanofibrils (CNFs) and silver nanoparticles (AgNPs) are nano-sized fillers widely used for enhancing the active functions of food packaging materials. However, nanomaterials may pose unexpected toxic effects on humans. Thus, the objective of this work was to develop a novel CNF/AgNP composite and investigate its properties and cytotoxicity. The CNF/AgNP composite was prepared via a reduction method using NaBH4. The AgNPs embedded in the composite showed an average size of 10.72 ±â€¯4.96 nm and a surface plasmon resonance (SPR) absorption peak at 397 nm. AgNPs were distributed individually in the composite after synthesis, but aggregated during film preparation. The formation of AgNPs disrupted hydrogen bonds between the hydroxyl groups of cellulose, weakening the hydrogen-bond intensity, as shown by FTIR. Silver ions were efficiently released from the composite film in the first 24 h. The CNF/AgNP composite exhibited inhibitory effects on Escherichia coli O157:H7 and Listeria monocytogenes. The composite (50-1000 µg/mL) did not significantly reduce the viability of Caco-2 and FHC colon cells, although the uptake of AgNPs through an endosomal mechanism was observed. These results suggest that the as-prepared CNF/AgNP composite could potentially be used as an antimicrobial material in active food packaging systems.


Assuntos
Materiais Biocompatíveis , Celulose , Embalagem de Alimentos , Nanopartículas Metálicas , Prata , Materiais Biocompatíveis/química , Linhagem Celular Tumoral , Sobrevivência Celular , Celulose/química , Humanos , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Prata/química , Análise Espectral
14.
Carbohydr Polym ; 205: 596-600, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30446146

RESUMO

This study aimed to develop a jellylike flexible substrate based on nanocellulose decorated with Ag nanoparticles (Ag/NC substrate) and explore its applications for rapid in-situ pesticide detections in fruits and vegetables by surface-enhanced Raman spectroscopy (SERS). The performances of Ag/NC substrate were characterized by rhodamine 6G (R6G). The limit of detection recorded by a portable Raman spectrometer is 10-8 M. The substrate still exhibited satisfactory sensitivity after 60-day preservation. Jellylike and slightly sticky Ag/NC substrate demonstrated good adaptabilities in attaching to sample surfaces and is suitable for in-situ SERS detection. Two types of pesticides on apple peels and cabbages were detected by rapid in-situ and non-invasive SERS method coupled with Ag/NC substrate. The lowest detectable level was 0.5 ng/cm2 for thiram and 5 ng/cm2 for thiabendazole, which were well below the maximum residue levels. These results demonstrate that Ag/NC substrate is sensitive for rapid in-situ multi-pesticide detection in food.


Assuntos
Celulose/química , Contaminação de Alimentos/análise , Frutas/química , Nanopartículas Metálicas/química , Praguicidas/análise , Verduras/química , Brassica/química , Limite de Detecção , Malus/química , Prata/química , Análise Espectral Raman/métodos , Tiabendazol/análise , Tiram/análise
15.
Food Chem ; 270: 229-235, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30174039

RESUMO

This study aimed to investigate the effects of acidic electrolyzed oxidizing water (AEW) treatment on storability and metabolism of reactive oxygen species (ROS) in blueberries cv. 'Brightwell' during storage at 4 °C. Results showed that, compared with the control blueberries, AEW treated-blueberries exhibited lower incidence of fruit decay, higher rate of commercially acceptable fruit, higher fruit firmness and skin hardness, and higher anthocyanin and total phenolics contents, along with higher activities of SOD, CAT and APX, higher antioxidant activity, but lower generation rate of superoxide anion and cell membrane permeability. These results demonstrated that AEW treatment for enhancing storability of harvested blueberries during storage may be mediated by regulating ROS metabolism, manifested as AEW increasing ROS scavenging capacity and reducing ROS accumulation, and thereby maintained the structural integrity of cellular membrane, which indicated that AEW treatment was a facile postharvest method for extending the shelf life of harvested blueberries.


Assuntos
Mirtilos Azuis (Planta)/química , Armazenamento de Alimentos/métodos , Espécies Reativas de Oxigênio/metabolismo , Antocianinas , Antioxidantes , Frutas , Água
16.
Food Chem ; 266: 299-308, 2018 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-30381189

RESUMO

This study aimed to investigate the effects of a novel chitosan formulation (Kadozan) treatment on disease development, response of disease resistance, metabolism of reactive oxygen species (ROS) in Peronophthora litchii-inoculated "Wuye" litchis. Compared with P. litchii-inoculated litchis, Kadozan-treated P. litchii-inoculated litchis exhibited lower fruit disease index, higher lignin content, higher activities of disease resistance-related enzymes (CHI, GLU and PAL), lower O2- generating rate and malondialdehyde content, higher activities of ROS scavenging enzymes (SOD, CAT and APX), higher contents of ascorbic acid and glutathione, and higher levels of reducing power and DPPH radical scavenging activity. These results suggest that Kadozan can be used to inhibit the growth of P. litchii in harvested litchis owning to the enhancement of disease resistance and ROS scavenging capacity, and decreases in O2- accumulation and membrane lipid peroxidation. Kadozan treatment can be used as a facile and novel method for suppressing postharvest pathogenic disease of litchis.

17.
J Agric Food Chem ; 2018 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-30403851

RESUMO

This study investigated the changes in metabolisms of membrane lipids and phenolics caused by Phomopsis longanae Chi infection in association with pericarp browning and fruit disease occurrence of postharvest longans. Compared with the uninoculated-longans, the longans inoculated by P. longanae exhibited higher cellular membrane permeability; higher PLD, lipase, and LOX activities; and higher levels of saturated fatty acids (SFAs) and phosphatidic acid but lower levels of phosphatidylinositol, phosphatidylcholine, and unsaturated fatty acids (USFAs). Additionally, the longans inoculated by P. longanae showed higher activities of POD and PPO but a lower amount of total phenolics. These findings suggested that infection of P. longanae enhanced activities of PLD-, lipase-, and LOX- stimulated degradations of membrane lipids and USFAs, which destroyed the integrity of the cell membrane structure, resulting in enzymatic browning by contact of phenolics with POD and PPO, and resulting in reduction of resistance to pathogen infection and accordingly accelerated disease occurrence of postharvest longan fruit.

18.
Front Microbiol ; 9: 2466, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30386318

RESUMO

Phomopsis longanae Chi is a major pathogenic fungus that infects harvested longan fruit. This study aimed to investigate the effects of P. longanae on reactive oxygen species (ROS) metabolism and its relation to the pericarp browning and disease development of harvested longan fruit during storage at 28°C and 90% relative humidity. Results showed that compared to the control longans, P. longanae-inoculated longans displayed higher indexes of pericarp browning and fruit disease, higher O2 -. generation rate, higher accumulation of malondialdehyde (MDA), lower contents of glutathione (GSH) and ascorbic acid (AsA), lower 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability and reducing power in pericarp. In addition, P. longanae-infected longans exhibited higher activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) in the first 2 days of storage, and lower activities of SOD, CAT, and APX during storage day 2-5 than those in the control longans. These findings indicated that pericarp browning and disease development of P. longanae-infected longan fruit might be the result of the reducing ROS scavenging ability and the increasing O2 -. generation rate, which might lead to the peroxidation of membrane lipid, the loss of compartmentalization in longan pericarp cells, and subsequently cause polyphenol oxidase (PPO) and peroxidase (POD) to contact with phenolic substrates which result in enzymatic browning of longan pericarp, as well as cause the decrease of disease resistance to P. longanae and stimulate disease development of harvested longan fruit.

19.
Front Microbiol ; 9: 2583, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30425698

RESUMO

Pestalotiopsis microspora (P. microspora) is one of dominant pathogenic fungi causing rotten disease in harvested Chinese olive (Canarium album Lour.) fruits. The purposes of this study were to evaluate the antifungal activities of ginger oleoresin (GO) against P. microspora and to illuminate the underlying action mechanisms. The in vitro assays indicate that GO exhibited strong antifungal activity against mycelial growth of P. microspore, and with 50%-inhibition concentration (EC 50) and 90%-inhibition concentration (EC 90) at 2.04 µL GO and 8.87 µL GO per mL propylene glycol, respectively, while the minimal inhibitory concentration (MIC) and minimal fungicidal concentration were at 10 µL GO and 30 µL GO per mL propylene glycol, respectively. Spore germination of P. microspora was inhibited by GO in a dose-dependent manner, and with 100% inhibition rate at the concentration of 8 µL GO per mL propylene glycol. Compared to the control, the cellular membrane permeability of P. microspora increased due to severe leakage of intercellular electrolytes, soluble proteins, and total sugars with the treatments (EC 50, EC 90) by GO during incubation. In addition, analysis of fatty acid contents and compositions in cellular membrane by GC-MS indicated that GO could significantly promote the degradation or peroxidation of unsaturated fatty acids in P. microspore, resulting in the enhancement of membrane fluidity. Moreover, observations of microstructure further showed the damage to plasma membrane and morphology of P. microspora caused by GO, which resulted in distortion, sunken and shriveled spores and mycelia of the pathogen. Furthermore, in vivo assay confirmed that over 3 MIC GO treatments remarkably suppressed disease development in P. microspore inoculated-Chinese olive fruit. These results demonstrate that owing to its strong antifungal activity, GO can be used as a promising antifungal agent to inhibit the growth of pathogenic fungi in Chinese olives.

20.
Conf Proc IEEE Eng Med Biol Soc ; 2018: 4492-4495, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30441349

RESUMO

Rapid and accurate detection of single-nucleotide polymorphism (SNP) in pathogenic mutants is crucial for broad fields from food safety monitoring to disease diagnostics and prognosis. Here, we developed a nanopore single-molecule sensor, coupled with the locked nucleic acid (LNA) technique, to accurately discriminate SNPs for detection of Shiga toxin producing Escherichia coli (STEC) O157:H7 pathogen serotype, and cancer-derived driver mutations EGFR L858R and KRAS G12D. This sensitive method, with a simplified, low cost, easy-to-operate LNA design, can be applied in food science and medical detection that need rapid and accurate determination of genetic variations.

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