Publications by authors named "Yongmei Xia"

35 Publications

A comparative study on physicochemical and micellar solubilization performance between monoglucosyl rebaudioside A and rebaudioside A.

J Sci Food Agric 2021 Oct 23. Epub 2021 Oct 23.

State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu, 214122, China.

Background: Rebaudioside A (RA) and its monoglucosyl derivative, as like rebaudioside D (RD) are the most popular stevia glycosides but possess poor solubility in water, which limited their application as edible surfactants, the applications as in micellar solubilization and drug delivery. Meanwhile, effect of the monoglucosyl attached to RA moiety remains unclear.

Results: Monoglucosyl rebaudioside A (RAG1) was synthesized via hydrolysizing the transglycosylation product of RA with 95% of RA converted. RAG1 content in raw reaction mixture was as high as 69.5% of total glycosides, and harvested with a content of 88.2% by simple filtration. The RAG1 exhibited an aqueous solubility of 87 folds of RA or 391 folds of RD at 25°C. The surface activity of RAG1 solution was higher than RA and invincible to RD. The RAG1 micelles promoted aqueous solubility of IDE up to 500 folds higher at 25°C. The cumulative release rate of IDE encapsulated in RAG1 micelles was 777.5% or 456.7% higher of that of free IDE in simulated gastric/intestinal fluids in 14h, respectively. The RAG1-IDE remained same in 98 days at 25°C.

Conclusion: The α-linked glucosyl to RA induced higher hydrophilicity and surface activity than that resulted by β-linked glucosyl, making RAG1 not only dramatically raised aqueous solubility of RA, but also endowed IDE folds higher in bioaccessibility, yet making the capsule stable at storage. The results would provide a new edible delivery nanocarrier for encapsulation of hydrophobic bioactive components. This article is protected by copyright. All rights reserved.
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http://dx.doi.org/10.1002/jsfa.11604DOI Listing
October 2021

The inhibitory mechanism of chlorogenic acid and its acylated derivatives on α-amylase and α-glucosidase.

Food Chem 2021 Oct 5;372:131334. Epub 2021 Oct 5.

State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, Jiangsu 214122, China. Electronic address:

Due to the poor lipophilicity of chlorogenic acid (CA), five CA derivatives (C2-CA, C4-CA, C6-CA, C8-CA, and C12-CA) with different lipophilicities were synthesized using acylation catalyzed by lipase in present study. The inhibitory activities and mechanisms of CA and its derivatives on α-amylase and α-glucosidase were then determined. Results showed that the inhibitory activities of CA derivatives on α-amylase and α-glucosidase were enhanced as lipophilicity increased, and the inhibitory activities of C12-CA were stronger than those of CA. IC values of C12-CA were 13.30 ± 0.26 μmol/mL for α-amylase and 3.42 ± 0.10 μmol/mL for α-glucosidase. C12-CA possessed the smallest K and K values, and its inhibitory actions on α-amylase and α-glucosidase were stronger than those of CA and the other derivatives. Effects of C12-CA on microenvironments of amino acid residues and secondary structures of α-amylase and α-glucosidase were greater than those of CA and the other derivatives.
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http://dx.doi.org/10.1016/j.foodchem.2021.131334DOI Listing
October 2021

Antioxidant activities of chlorogenic acid derivatives with different acyl donor chain lengths and their stabilities during in vitro simulated gastrointestinal digestion.

Food Chem 2021 Apr 20;357:129904. Epub 2021 Apr 20.

State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, Jiangsu 214122, China. Electronic address:

In this study, chlorogenic acid (CA) was acylated with vinyl esters of different carbon chain lengths under the action of the lipase Lipozyme RM. Five CA derivatives (C2-CA, C4-CA, C6-CA, C8-CA, and C12-CA) with different lipophilicities were obtained, and their digestive stabilities and antioxidant activities were evaluated. The lipophilicities were positively correlated with the digestive stabilities of CA derivatives. The antioxidant activities of CA derivatives did not change with the reduction of phenolic hydroxyl groups, and their capacity to scavenge 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•) and 1,1-diphenyl-2-picrylhydrazyl (DPPH•) were similar to those of CA. In cellular antioxidant activity (CAA) tests, it was found that the capacity of these derivates to cross cell membranes were enhanced upon enhancing lipophilicity, and their antioxidant activities were improved. C12-CA showed the best antioxidant activity with a median effective dose (EC) of 9.40 μg/mL, which was significantly lower than that of CA (i.e., 29.08 μg/mL).
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http://dx.doi.org/10.1016/j.foodchem.2021.129904DOI Listing
April 2021

Durable Superhydrophobic Wood via One-Step Immersion in Composite Silane Solution.

ACS Omega 2021 Mar 11;6(11):7266-7274. Epub 2021 Mar 11.

Department of Mechanical Engineering, York University, Toronto, Ontario M3J 1P3, Canada.

A superhydrophobic coating endows pristine hydrophilic wood with excellent water/moisture repellency and thus prolongs its service life. Generally, the superhydrophobic coating on wood is fabricated by a two-step process in which the nanoparticles are first introduced onto the surface and then modified by low-surface-energy molecules. Herein, for the first time, we have fabricated the superhydrophobic wood via a one-step process free of nanoparticles by immersing the pristine hydrophilic wood, such as pine, balsawood, and basswood, into a composite silane solution of hexadecyltrimethoxysilane and methyltrimethoxysilane. The wood remains superhydrophobic or highly hydrophobic after long-term exposure to mechanical damage (such as abrading, knife-cutting, and tape-peeling), chemical damage (such as immersion in acid, alkali, or ethanol), and environmental impacting (such as UV irradiation and low/high-temperature exposure).
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http://dx.doi.org/10.1021/acsomega.0c04099DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7992087PMC
March 2021

Enhanced Production of Soluble α-Amylase in through Chaperone Co-Expression, Heat Treatment and Fermentation Optimization.

J Microbiol Biotechnol 2021 Apr;31(4):570-583

State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, P.R. China.

α-amylase can hydrolyze α-1,4 linkages in starch and related carbohydrates under hyperthermophilic condition (~ 100°C), showing great potential in a wide range of industrial applications, while its relatively low productivity from heterologous hosts has limited the industrial applications. , a gram-positive bacterium, has been widely used in industrial production for its non-pathogenic and powerful secretory characteristics. This study was conducted to increase production of α-amylase in through three strategies. Initial experiments showed that co-expression of molecular chaperone peptidyl-prolyl -trans isomerase through genomic integration mode, using a CRISPR/Cas9 system, increased soluble amylase production. Therefore, considering that native α-amylase is produced within a hyperthermophilic environment and is highly thermostable, heat treatment of intact culture at 90°C for 15 min was performed, thereby greatly increasing soluble amylase production. After optimization of the culture conditions (nitrogen source, carbon source, metal ion, temperature and pH), experiments in a 3-L fermenter yielded a soluble activity of 3,806.7 U/ml, which was 3.3- and 28.2-fold those of a control without heat treatment (1,155.1 U/ml) and an empty expression vector control (135.1 U/ml), respectively. This represents the highest α-amylase production reported to date and should promote innovation in the starch liquefaction process and related industrial productions. Meanwhile, heat treatment, which may promote folding of aggregated α-amylase into a soluble, active form through the transfer of kinetic energy, may be of general benefit when producing proteins from thermophilic archaea.
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http://dx.doi.org/10.4014/jmb.2101.01039DOI Listing
April 2021

A family of chitosan-peptide conjugates provides broad HLB values, enhancing emulsion's stability, antioxidant and drug release capacity.

Carbohydr Polym 2021 Apr 19;258:117653. Epub 2021 Jan 19.

School of Chemical and Material Engineering, Jiangnan University, Wuxi, Jiangsu 214122, China.

Strong hydrophilicity of polysaccharide and physicochemical instability of peptides limit application of polysaccharide-peptide mixtures in food industry. In this study, a natural resource platform of polysaccharide-peptide conjugates was constructed through Maillard reaction from chitosan and casein hydrophobic peptide. By choosing the molecular weight and deacetylation degree of chitosan and other reaction parameters, the conjugated chitosan-peptides possess extensive HLB values from 6 to 14 were obtained with grafting degree of 3.10%-15.08%. The conjugates have gained dramatically improved emulsifying ability, and endowed the emulsion higher antioxidant capacity than the peptide, chitosan and the mixture of peptide-chitosan has. Emulsions prepared with all conjugates exhibited long-term stability and strengthened tolerance towards temperature and electrolyte stimuli. This stable emulsion system also provided an effective encapsulation, protection and controlled release of curcumin, which may provide a method for transfer polysaccharides to stable emulsifiers with broader HLB values and application.
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http://dx.doi.org/10.1016/j.carbpol.2021.117653DOI Listing
April 2021

Bioavailability and antioxidant activity of nanotechnology-based botanic antioxidants.

J Food Sci 2021 Feb 12;86(2):284-292. Epub 2021 Jan 12.

Key Laboratory of Synthetic and Biological Colloids (Ministry of Education), School of Chemical and Materials Engineering, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu, 214122, China.

Botanic bioactive substances have issues with their solubility, stability, and oral bioavailability in the application, which could be improved by nanotechnologies. In another hands, green synthesis of nanoparticles (NPs) with plant extract is also a promising technology for preparation of NPs due to its safety advantage, yet the bioactive botanic substances that could be more than the assistant of the green synthesis of NPs. Based on the above concerns, this review summarized the preparation of botanic NPs with various plant extract, their solubility, stability, and oral bioavailability; specific attention has been paid to the botanic Ag/Au NPs, their capacity of antioxidant, bioavailability, antimicrobial, anti-inflammatory, and anticancer.
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http://dx.doi.org/10.1111/1750-3841.15582DOI Listing
February 2021

Modification of γ-Cyclodextrin Glycosyltransferase and Addition of Complexing Agents to Increase γ-Cyclodextrin Production.

J Agric Food Chem 2020 Oct 14;68(43):12079-12085. Epub 2020 Oct 14.

State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China.

γ-Cyclodextrin (γ-CD), a cyclic oligosaccharide containing eight glucose units linked by α-1,4-glycosidic bonds, can be produced from starch using cyclodextrin glycosyltransferase (CGTase). Unfortunately, this enzymatic process produces mixtures of α-, β-, and γ-CD. In this study, amino acid residues in the subsite -3 (T47 and F91) and the central subsite (Y186) of γ-CGTase were modified to improve the γ-CD production. The cyclization activities and product specificities of mutants T47H and F91W were similar to those of the wild-type. The cyclization activities of mutants F91N and F91L were significantly greater than those of the wild-type but their γ-CD product specificities were lower. Finally, the central subsite mutant Y186W displayed a γ-CD specificity (94.6%) significantly greater than that of the wild-type (77.1%). To maximize the γ-CD yield, the effects of added complexing agents were investigated. Among the cyclic complexing agents tested, low-boiling cyclododecanone was the smallest that precipitated with γ-CD. When cyclododecanone was used with Y186W, the total CD yield reached 72.6%, and 96.6% of the product was γ-CD. These results, which represent the highest γ-CD yield ever reported, may provide a way to improve large-scale γ-CD preparation and expand the uses of γ-CD in the future.
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http://dx.doi.org/10.1021/acs.jafc.0c05408DOI Listing
October 2020

Reaction coupling separation for isosteviol production from stevioside catalyzed by acidic ion-exchange resin.

Bioprocess Biosyst Eng 2021 Jan 28;44(1):151-159. Epub 2020 Aug 28.

Key Laboratory of Nuclear Medicine of Ministry of Health, Jiangsu Institute of Nuclear Medicine, Wuxi, 214063, Jiangsu, China.

Isosteviol, a prodrug used to be obtained via Wagner-Meerwein rearrangement from steviol with low yield and long reaction time. Herein, an in-situ separation-coupling-reaction is presented to prepare isosteviol from the natural sweetener stevioside. Simply with in-situ water-washing, the product containing 92.98% purity of isosteviol was obtained with a stevioside conversion of 97.23% from a packet bed reactor without further separation. Within the assayed inorganic acid, organic acids and acidic ionic liquids, the acidic ion-exchange resins provided higher product specificity towards isosteviol. Furthermore, comparing to 5-Fluorouracil, the product presented similar and even stronger inhibition on proliferation of the assayed human cancer cells in a time and dose-dependence by causing cell phase arrest. Isosteviol treatment caused G1 arrest on SGC-7901, HCT-8 and HCT-116 cells, S arrest on HepG2, Huh-7 and HepG3B cells, and G2 arrest on MGC-803 cells, respectively. Reaction coupling separation for isosteviol production catalyzed by acidic ion-exchange resin.
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http://dx.doi.org/10.1007/s00449-020-02431-4DOI Listing
January 2021

Fabrication of a Z-Scheme {001}/{110} Facet Heterojunction in BiOCl to Promote Spatial Charge Separation.

ACS Appl Mater Interfaces 2020 Jul 1;12(28):31532-31541. Epub 2020 Jul 1.

Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, P. R. China.

The realization of high-efficiency carrier separation is of great meaning and challenge, which is crucial to boost the photocatalytic activity. Herein, we tackle this bottleneck by fabricating a {110}/{001} facet junction to effectively facilitate the separation of charge carriers. In this study, two different BiOCl nanoplates (BiOCl-H1 and BiOCl-H2) with coexposed {110} and {001} facets were synthesized under different pH conditions. The ratio of these facets could be adjusted by the pH value of the precursor. It was discovered that the photocatalytic performance of the obtained sample for pollutant removal is dependent on the facet ratio of these facets. Theoretical calculation results show the difference in the electronic structure and staggered alignment of these facets, thus endowing BiOCl with the possibility to fabricate a facet junction. Based on our logical analyses, the Z-scheme charge-transfer mechanism was accordingly put forward. Our work opens a new avenue for the construction of a Z-scheme facet heterojunction to enhance charge separation.
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http://dx.doi.org/10.1021/acsami.0c08687DOI Listing
July 2020

A molecular framework underlying the compound leaf pattern of Medicago truncatula.

Nat Plants 2020 05 11;6(5):511-521. Epub 2020 May 11.

CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, CAS Center for Excellence for Molecular Plant Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, China.

Compound leaves show more complex patterns than simple leaves, and this is mainly because of a specific morphogenetic process (leaflet initiation and arrangement) that occurs during their development. How the relevant morphogenetic activity is established and modulated to form a proper pattern of leaflets is a central question. Here we show that the trifoliate leaf pattern of the model leguminous plant Medicago truncatula is controlled by the BEL1-like homeodomain protein PINNATE-LIKE PENTAFOLIATA1 (PINNA1). We identify PINNA1 as a determinacy factor during leaf morphogenesis that directly represses transcription of the LEAFY (LFY) orthologue SINGLE LEAFLET1 (SGL1), which encodes an indeterminacy factor key to the morphogenetic activity maintenance. PINNA1 functions alone in the terminal leaflet region and synergizes with another determinacy factor, the C2H2 zinc finger protein PALMATE-LIKE PENTAFOLIATA1 (PALM1), in the lateral leaflet regions to define the spatiotemporal expression of SGL1, leading to an elaborate control of morphogenetic activity. This study reveals a framework for trifoliate leaf-pattern formation and sheds light on mechanisms generating diverse leaf forms.
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http://dx.doi.org/10.1038/s41477-020-0642-2DOI Listing
May 2020

Polyphenols from Stevia rebaudiana (Bertoni) leaves and their functional properties.

J Food Sci 2020 Feb 28;85(2):240-248. Epub 2020 Jan 28.

Dept. of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan Univ., 130 Dong'an Rood, Shanghai, 200032, China.

The major polyphenol components from Stevia rebaudiana (Bertoni) leaves (PPS) are chlorogenic acids, a polyphenol family of esters, including hydroxycinnamic acids with quinic acid, which possesses excellent hydrophilic antioxidant activity and other therapeutic properties. As an abundant byproduct during production of steviol glycosides, the PPS would be a new antioxidantive food resource or additives applied in foods and drugs with antidiabetic function. Extracting PPS from S. rebaudiana (Bertoni) leaves together with steviol glycosides would be an economic process, which will change most operation process in current Stevia factories. The quantification of PPS needs to be unified for regulation. In view of the current regulation status of polyphenols and extracts from Stevia, the PPS would be ready to go to the market with few regulation barriers in the near future. This review will summarize the analysis, extraction, and some functional properties of PPS, such as antioxidant, antidiabetic, antimicrobial, anti-inflammatory, and anticancer.
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http://dx.doi.org/10.1111/1750-3841.15017DOI Listing
February 2020

RQ3, A Natural Rebaudioside D Isomer, Was Obtained from Glucosylation of Rebaudioside A Catalyzed by the CGTase Toruzyme 3.0 L.

J Agric Food Chem 2019 Jul 1;67(28):8020-8028. Epub 2019 Jul 1.

Pharmaceutical Analytical & Solid-State Chemistry Research Center, Shanghai Institute of Materia Medical , Chinese Academy of Sciences , Shanghai 201203 , China.

In this study, a monoglucosyl rebaudioside A product was isolated from the mixture of glucosylated rebaudioside A obtained from the most reported and industrial used cyclodextrin glycosyl transferase, Toruzyme 3.0 L (CGTase, Toruzyme 3.0 L). The molecular structure of the monoglucosyl rebaudioside A was characterized using LC-MS/MS and methylation analysis combined with 1D and 2D NMR, indicating that it is 13-[(2--(3-α--D-glucopyranosyl)-β-D-glucopyranosyl-3--β-D-glucopyranosyl-β-D-glucopyranosyl)oxy] -kaur-16--19-oic acid β-D-glucopyranosyl ester (also known as RQ3, which naturally exists in Stevia extract as an isomer of rebaudioside D). This study may help to further understand the reaction mechanism of glucosylation of steviol glycoside assisted by Toruzyme 3.0 L in the aspect of molecule linkage pattern, and also benefit the application of the glucosylated rebaudiosides.
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http://dx.doi.org/10.1021/acs.jafc.9b02545DOI Listing
July 2019

Improved Thermostability of Maltooligosyltrehalose Synthase from Arthrobacter ramosus by Directed Evolution and Site-Directed Mutagenesis.

J Agric Food Chem 2019 May 30;67(19):5587-5595. Epub 2019 Apr 30.

Maltooligosyltrehalose synthase (MTSase) is a key enzyme in trehalose production. MTSase from Arthrobacter ramosus has poor thermostability, limiting its industrial use. In this study, mutant G415P was obtained by directed evolution and S361R/S444E was subsequently generated based on a structure analysis of the region around G415. The t of G415P and S361R/S444E at 60 °C increased by 3.0- and 3.2-fold, respectively, compared with the wild-type enzyme. A triple mutant (G415P/S361R/S444E) was obtained through a combination of the above mutants, and its t significantly increased by 19.7-fold. Kinetic and thermodynamic stability results showed that the T and T values of the triple mutant increased by 7.1 and 7.3 °C, respectively, compared with those of the wild-type enzyme. When the triple mutant was used in trehalose production, the yield reached 71.6%, higher than the 70.3% achieved with the wild-type. Thus, the mutant has a potential application for industrial trehalose production.
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http://dx.doi.org/10.1021/acs.jafc.9b01123DOI Listing
May 2019

Steviol, a natural product inhibits proliferation of the gastrointestinal cancer cells intensively.

Oncotarget 2018 May 29;9(41):26299-26308. Epub 2018 May 29.

Key Laboratory of Nuclear Medicine of Ministry of Health, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu 214063, China.

New anticancer agents with lower toxicity have been always urged because of drug resistance associated with overused chemotherapy agents. In this study, steviol, a colonic metabolite of natural sweetener and also a component in leaves of , was found to possess intensive anticancer activity on the human gastrointestinal cancer cells. Steviol inhibited six human gastrointestinal cancer cells intensively as 5-fluorouracil did at 100 μg/mL. The inhibition mechanism follows mitochondrial apoptotic pathway that was evidenced by increase of Bax/Bcl-2 ratio, activation of p21 and p53; and caspase 3-independent mechanism was also involved. These results are consistent with the miRNA expression analysis. The most regulated miRNAs in the steviol treated gastrointestinal cancer cells were miR-203a-3p (log2 =1.32) and miR-6088 (log2 =-2.54) in HCT-116, miR-1268b (log2 =19.85) and miR-23c (log2 =-2.05) in MKN-45. In view of the metabolic characteristics of steviol and its cytotoxicity on the cancer cells, steviol could be a chemotherapy agent potentially for cancer treatment.
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http://dx.doi.org/10.18632/oncotarget.25233DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5995179PMC
May 2018

Fabrication and Photocatalytic Property of Novel SrTiO/BiOI Nanocomposites.

Nanoscale Res Lett 2018 May 11;13(1):148. Epub 2018 May 11.

Huaide College, Changzhou University, Jingjiang, 214500, China.

The novel SrTiO/BiOI nanocomposites were successfully fabricated by a thermal decomposition approach. The as-prepared samples were characterized by XRD, XPS, SEM, EDS, FTIR, DRS and PL spectra. The results show that the SrTiO/BiOI nanocomposites are composed of perovskite SrTiO nanoparticles and tetragonal BiOI nanorods. The SrTiO/BiOI nanocomposites exhibit an excellent photocatalytic performance for the degradation of RhB solution under simulated solar light irradiation, which is superior to that of pristine BiOI and SrTiO. In particular, the 30 wt% SrTiO/BiOI nanocomposite is found as the optimal composites, over which the dye degradation reaches 89.6% for 150 min of photocatalysis. The photocatalytic degradation rate of the 30 wt% SrTiO/BiOI nanocomposite is found to be 3.97 times and 12.5 times higher than that of bare BiOI and SrTiO, respectively. The reactive species trapping experiments suggest that [Formula: see text] and holes are the main active species responsible for the RhB degradation. In addition, the PL spectra elucidate the effective separation of photoinduced electron-hole pairs. Further, the possible photocatalytic mechanism of the SrTiO/BiOI nanocomposites is also elucidated based on the experimental evidences.
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http://dx.doi.org/10.1186/s11671-018-2558-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5948192PMC
May 2018

Neutral and acid-adapted fatty acid vesicles of conjugated linoleic acid.

Colloids Surf B Biointerfaces 2018 Jul 20;167:385-391. Epub 2018 Apr 20.

Key Laboratory of Synthetic and Biological Colloids (Ministry of Education), School of Chemical and Material Engineering, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu, 214122, PR China. Electronic address:

FAVs (fatty acid vesicles), originated from natural biomass and created available biointerface, have advantages of biocompatibility, low-cost, and easy self-assembly in aqueous solution due to their dynamic feature. However, there is no example of applying FAVs in contact with human body since they are inherently alkaline-adapted and pH windows for the FAV formation and application are very narrow and far away from the physiological pH range. In this work an attempt to turn the alkaline-adapted FAVs into neutral and acid-adapted ones was made by fabricating the amphiphile-hybrid vesicles of CLA (conjugated linoleic acid) with a typical cosmetic emulsifier SDS (sodium dodecylsulfate) and/or a co-emulsifier DA (dodecyl alcohol). pH windows for the SDS- and/or DA-hybrid FAV formation of CLA were judged by using dynamic light scattering criterion, and confirmed by small-angle X-ray scattering and room temperature transmission electron microscopy. The experimental results show that with the aid of H-bonding and ion-dipole forces among molecules of CLA, SDS and DA within the hybrid vesicle walls that were identified by Fourier transform infrared analysis, much wider pH windows of 2.5-11.7 for the hybrid FAVs were obtained by expansion from 8.0-9.0 for FAV of CLA alone, which was composition-dependent and made the hybrid FAVs become neutral and acid-adapted.
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http://dx.doi.org/10.1016/j.colsurfb.2018.04.035DOI Listing
July 2018

Seed dormancy-life form profile for 358 species from the Xishuangbanna seasonal tropical rainforest, Yunnan Province, China compared to world database.

Sci Rep 2018 03 16;8(1):4674. Epub 2018 Mar 16.

Department of Biology, University of Kentucky, Lexington, Kentucky, 40506, USA.

Seed dormancy profiles are available for the major vegetation regions/types on earth. These were constructed using a composite of data from locations within each region. Furthermore, the proportion of species with nondormant (ND) seeds and the five classes of dormancy is available for each life form in each region. Using these data, we asked: will the results be the same if many species from a specific area as opposed to data compiled from many locationsare considered? Germination was tested for fresh seeds of 358 species in 95 families from the Xishuangbanna seasonal tropical rainforest (XSTRF): 177 trees, 66 shrubs, 57 vines and 58 herbs. Seeds of 12.3% of the species were ND, and 0.3, 14.8, 60.6, 12.0 and 0% of the species had morphological (MD), morphophysiological (MPD), physiological (PD), physical (PY), and combinational (PY + PD) dormancy, respectively. PD was more important than ND in all life forms, PY was highest in shrubs, MD was not important in any life form and MPD was most common for herb and vines. The seed dormancy profile for XSTRF differs considerably from the composite profile for this vegetation type worldwide, most obviously in ND being much lower and PD much higher in XSTRF.
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http://dx.doi.org/10.1038/s41598-018-22930-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5856844PMC
March 2018

Triple helix conformation of β-d-glucan from Ganoderma lucidum and effect of molecular weight on its immunostimulatory activity.

Int J Biol Macromol 2018 Jul 13;114:1064-1070. Epub 2018 Mar 13.

School of Chemical and Material Engineering, State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Agriculture and Agri-Food Canada, Guelph Food Research Centre, 93 Stone Rd. W., Guelph, Ontario N1G 5C9, Canada. Electronic address:

β-d-glucan (GLP20) isolated from Ganoderma lucidum fruiting bodies was successfully fractionated into five fractions with different weight-average molecular weights (M) through ultrasonic irradiation. The M, radius of gyration (R), hydrodynamic radius (R) and intrinsic viscosity ([η]) of these fractions in phosphate buffered saline (PBS) aqueous solution were determined using HPSEC-MALLS-RI-VS system. The results indicated that β-d-glucan displayed rigid chain conformations with ρ values lager than 2.06 for the five fractions. By applying the polymer solution theory, the exponent (ν and α) values of R = kM and [η] = kM were calculated as 0.72 and 1.05, respectively, which confirmed the rigid chain conformation of glucans with M from 2.9 × 10 to 2.42 × 10 g·mol. According to the known theory for chains, the molar mass per unit contour length M, persistence length q and contour length h per main-chain glucose residue were estimated to be 2150 nm, 128 nm and 0.30 nm, respectively, which indicated that the glucan existed as triple-helical chains in PBS aqueous solution. Bioactivity study of glucan fractions on lymphocytes and THP-1 macrophages demonstrated that all these fractions could stimulate lymphocyte proliferation, promote macrophages to form pseudopodia, and enhance the levels of inflammatory cytokines IL-6 and TNF-α. Meanwhile, the glucan fractions with M higher than 1.82 × 10 g·mol exhibited better activity on enhancing the release of inflammatory cytokines.
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http://dx.doi.org/10.1016/j.ijbiomac.2018.03.054DOI Listing
July 2018

Recombinant expression, characterization, and application of a phospholipase B from Fusarium oxysporum.

J Biotechnol 2017 Jan 8;242:92-100. Epub 2016 Dec 8.

State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.

In this study, a gene encoding a putative lipase from Fusarium oxysporum was optimized via codon optimization and expressed in Pichia pastoris KM71. The gene product was identified as a phospholipase B (PLB). The engineered P. pastoris was further cultured in a 3.6-L bioreactor. After optimization of the induction conditions, this system produced 6.6mgmL protein and 6503.8UmL PLB activity in the culture medium. Efficient expression of this PLB in P. pastoris should reduce the costs of production and application. The purified enzyme, with a specific activity of 1170Umg, was optimally active at pH 5.0 and 55°C. The results of a degumming experiment performed using the recombinant PLB showed that the phosphorus content of a test oil was decreased from 75.88ppm to 3.3ppm in 2h under optimal reaction conditions. This study provides a basis for the industrial use of F. oxysporum PLB in oil degumming applications.
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http://dx.doi.org/10.1016/j.jbiotec.2016.12.009DOI Listing
January 2017

Short-chain aliphatic ester synthesis using Thermobifida fusca cutinase.

Food Chem 2016 Sep 17;206:131-6. Epub 2016 Mar 17.

State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China.

Short-chain aliphatic esters are commonly used as fruit flavorings in the food industry. In this study, Thermobifida fusca (T. fusca) cutinase was used for the synthesis of aliphatic esters, and the maximum yield of ethyl caproate reached 99.2% at a cutinase concentration of 50U/ml, 40°C, and water content of 0.5%, representing the highest ester yield to date. The cutinase-catalyzed esterification displayed strong tolerance for water content (up to 8%) and acid concentration (up to 0.8M). At substrate concentrations ⩽0.8M, the ester yield remained above 80%. Moreover, ester yields of more than 98% and 95% were achieved for acids of C3-C8 and alcohols of C1-C6, respectively, indicating extensive chain length selectivity of the cutinase. These results demonstrate the superior ability of T. fusca cutinase to catalyze the synthesis of short-chain esters. This study provides the basis for industrial production of short-chain esters using T. fusca cutinase.
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http://dx.doi.org/10.1016/j.foodchem.2016.03.051DOI Listing
September 2016

Metal-free three-component oxyazidation of alkenes with trimethylsilyl azide and N-hydroxyphthalimide.

J Org Chem 2015 Jan 18;80(1):290-5. Epub 2014 Dec 18.

‡State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, China.

A novel and facile oxyazidation of alkenes under metal-free and mild conditions has been reported. A remarkable feature of the developed procedure is consecutive construction of C-O and C-N bonds in one step. The process allows quick and selective assembly of alkyl azide from readily available starting materials, where N-hydroxyphthalimide was used as an oxygen-radical precursor and TMSN3 as the N3 source. A range of aromatic alkenes bearing synthetically useful functional groups was tolerated.
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http://dx.doi.org/10.1021/jo502327rDOI Listing
January 2015

Solid-state structure of gelatin-mono epoxy terminated polydimethylsiloxane polymer: effect of electrostatic and hydrophobic interactions.

Colloids Surf B Biointerfaces 2014 Nov 1;123:945-50. Epub 2014 Nov 1.

Key Laboratory of Fine Chemicals of Shandong Province, Qilu University of Technology, Jinan 250353, PR China; School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, PR China. Electronic address:

In this study, a hybrid synthetic gelatin-mono epoxy terminated polydimethylsiloxane polymer (PDMS-E grafted gelatin (PGG)) was successfully synthesized on a large scale. Supramolecular structure of gelatin, which was decided by the sophisticated inter- and intra-molecular interactions, significantly affected the self-assembly and phase behavior of PGG. Interestingly, the supramolecular organization of PGG could be tuned finely by negatively charged surfactants, such as sodium dodecyl sulfate (SDS) and sodium tetradecyl sulfonate (STSo), as revealed by high-resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM), light microscopy (LM), and atomic force microscopy (AFM). SEM images exhibited the presence of spherical aggregates in PGG/SDS films while hexagonal array was observed in PGG/STSo films. The results of LM revealed that when PGG/STSo solution was dried, a successive structural transformation from spheres to hexagons, via sticks and butterfly-shaped aggregates as intermediates, was observed. However, the morphologies of the aggregates formed in PGG/SDS system did not exhibit any obvious change upon drying. Attenuated total reflection-Fourier transform infrared spectra combined with AFM observations indicated that the secondary structure and aggregation behavior of gelatin was modified with the change in the electrostatic and hydrophobic interactions, leading to the formation of diversified solid-state structures of PGG.
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http://dx.doi.org/10.1016/j.colsurfb.2014.10.055DOI Listing
November 2014

Selective oxygenation of alkynes: a direct approach to diketones and vinyl acetate.

Org Biomol Chem 2014 Dec;12(48):9909-13

The Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi, Jiangsu 214122, China.

Arylalkynes can be converted into α-diketones with the use of a copper catalyst, and also be transformed into vinyl acetates under metal-free conditions, both in the presence of PhI(OAc)2 as an oxidant at room temperature. A series of substituted α-diketones were prepared in moderate to good yields. A variety of vinyl halides could be regio- and stereo-selectively synthesized under mild conditions, and I, Br and Cl could be all easily embedded into the alkynes.
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http://dx.doi.org/10.1039/c4ob01404aDOI Listing
December 2014

Low-temperature solution growth of ZnO nanocone/highly oriented nanorod arrays on copper.

J Phys Chem B 2014 Oct 6;118(41):12002-7. Epub 2014 Oct 6.

Jiangsu Key Laboratory of Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University , Nanjing 211189, People's Republic of China.

Solution-phase approaches to one-dimensional (1D) ZnO nanostructure arrays are appealing because of their good potential for scale-up. Allowing for a wide variety of substrate material compatibility and saving energy, it is very essential to further research the low-temperature growth process of 1D ZnO nanostructure arrays and its detailed growth mechanism. In this study, large-scale misaligned hexagonal ZnO nancone arrays were synthesized on bare copper foil, while large-scale well-aligned, and highly oriented ZnO nanorod arrays were grown on seeded copper foil through a facile solution processing method at normal atmospheric pressure at 35 °C. X-ray diffraction analysis verified the crystalline nature of the ZnO nanocone/nanorods, and transmission electron microscopy further confirmed the single-crystal nature and the preferential growth direction of the ZnO nanocone/nanorods. The room-temperature photoluminescence measurement qualitatively identified the intrinsic point defects in the ZnO nanocones/nanorods. Besides, the detailed growth behavior of ZnO was discussed with and without a ZnO seed layer, which provides useful information to propose the growth mechanism of the nanocone/nanorods in the low-temperature solution. The method developed here can be easily scaled up to fabricate ZnO nanostructures for many important applications in field emission display, gas sensors, and superhydrophobic surfaces.
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http://dx.doi.org/10.1021/jp502873zDOI Listing
October 2014

Transglycosylation of stevioside to improve the edulcorant quality by lower substitution using cornstarch hydrolyzate and CGTase.

Food Chem 2013 Jun 12;138(2-3):2064-9. Epub 2012 Nov 12.

State Key Laboratory of Food Science and Technology, School of Chemical and Materials Engineering, Jiangnan University, Wuxi, Jiangsu 214122, China.

Stevioside is an abundant sweetener extracted from Stevia rebaudiana leaf with a bitter aftertaste. Enzymatic transglycosylation of stevioside is a solution to improve the edulcorant quality of stevioside, but highly derivatised stevioside coming with high conversion of stevioside is undesired. In this experiment, the transglycosylation of stevioside was investigated by using a commercial cyclodextrin glucanotransferase and cornstarch hydrolyzate. With controlled parameters, the product was mainly composed of mono- and di-glucosylated stevioside while the highest stevioside conversion reached 77.11%. Neither kinetic nor thermodynamic factor stimulated the formation of high substituted steviosides. The simultaneous hydrolysis in the reaction might inhibit the yield of highly substituted steviosides.
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http://dx.doi.org/10.1016/j.foodchem.2012.10.124DOI Listing
June 2013

Structure evolution of gelatin particles induced by pH and ionic strength.

Microsc Res Tech 2013 Mar 28;76(3):272-81. Epub 2012 Dec 28.

Department of Appiled Chemistry, School of Chemical and Material Engineering, Jiangnan University, Wuxi, People's Republic of China.

Microstructure of gelatin particles played a key role in determining the physicochemical properties of gelatin. Ionic strength and pH as systematic manners were considered to affect gelatin particles structure on the micrometer scale. Scanning electron microscopy was used for depicting the morphologies of gelatin particles. Increasing pH to 10.0 or decreasing pH to 4.0, spherical, spindle, and irregular aggregates of gelatin particles at 2, 6, 10, and 14% solution (w/w) were all transformed to spindle aggregates. When NaCl was added to the system, the molecular chains of gelatin possibly rearranged themselves in a stretched state, and the ribbon aggregates was observed. The structural transitions of gelatin aggregates were strongly depended on the electrostatic repulsion. In the gelatin-sodium dodecyl sulfate (SDS) case, the micrometer scale of aggregates was larger and the different degrees of cross-links were induced through hydrophobic interaction and electrostatic repulsion.
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http://dx.doi.org/10.1002/jemt.22164DOI Listing
March 2013

Flavonoid-mediated inhibition of SARS coronavirus 3C-like protease expressed in Pichia pastoris.

Biotechnol Lett 2012 May 15;34(5):831-8. Epub 2012 Feb 15.

School of Biological Sciences and Technology and the Research Institute for Catalysis, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju, 500-757, Republic of Korea.

The 3C-like protease (3CL(pro)) of severe acute respiratory syndrome associated coronavirus (SARS-CoV) is vital for SARS-CoV replication and is a promising drug target. Recombinant 3CL(pro) was expressed in Pichia pastoris GS115 as a 42 kDa protein that displayed a K ( m ) of 15 ± 2 μM with Dabcyl-KTSAVLQSGFRKME-Edans as substrate. Purified 3CL(pro) was used for inhibition and kinetic assays with seven flavonoid compounds. The IC(50) of six flavonoid compounds were 47-381 μM. Quercetin, epigallocatechin gallate and gallocatechin gallate (GCG) displayed good inhibition toward 3CL(pro) with IC(50) values of 73, 73 and 47 μM, respectively. GCG showed a competitive inhibition pattern with K ( i ) value of 25 ± 1.7 μM. In molecular docking experiments, GCG displayed a binding energy of -14 kcal mol(-1) to the active site of 3CL(pro) and the galloyl moiety at 3-OH position was required for 3CL(pro) inhibition activity.
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http://dx.doi.org/10.1007/s10529-011-0845-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7087583PMC
May 2012

Animal studies of 99mTc-i-PIDP: a new bone imaging agent.

Appl Radiat Isot 2011 Sep 9;69(9):1169-75. Epub 2011 Apr 9.

Key Laboratory of Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, PR China.

This study was to investigate the preparation and biodistribution of (99m)Tc-labeled novel zoledronic acid derivative 1-hydroxy-2-(2-isopropyl-1H-imidazole-1-yl) ethylidene-1,1-bisphosphonic ((99m)Tc-i-PIDP) as a potential bone imaging agent. Satisfactory labeling results (radiochemical purity over 95%) were obtained when the amount of i-PIDP, Na(99m)TcO(4), and SnCl(2)·2H(2)O, were 5 mg, 37 MBq, and 100 μg, respectively, the pH value was between 4.0 and 6.0, and the labeling reaction continued for 30 min. The labeled complex was stable at least up to 6h in vitro. The biodistribution and pharmacokinetics studies in mice and single photon emission computed tomography (SPECT) bone scan in rabbit of (99m)Tc-i-PIDP were systematically studied. The results showed that the bone uptake is up to 9.63%ID/g at 60 min after injection of (99m)Tc-i-PIDP. The pharmacokinetic studies indicate that the data can be fitted to a two-compartment model with the equation of C=5.80e(-0.20t)+2.66e(-0.01t). A plain bone image was obtained at 1 h. All of the results suggested that (99m)Tc-i-PIDP is worthy of future investigation as a novel bone imaging agent.
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http://dx.doi.org/10.1016/j.apradiso.2011.03.045DOI Listing
September 2011
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