Publications by authors named "Zhengqiang Jiang"

95 Publications

Host sunflower-induced silencing of parasitism-related genes confers resistance to invading Orobanche cumana.

Plant Physiol 2021 Mar;185(2):424-440

Key Laboratory of Forage and Endemic Crop Biotechnology, Ministry of Education, School of Life Sciences, Inner Mongolia University, Hohhot 010070, P. R. China.

Orobanche cumana is a holoparasitic plant that attaches to host-plant roots and seriously reduces the yield of sunflower (Helianthus annuus L.). Effective control methods are lacking with only a few known sources of genetic resistance. In this study, a seed-soak agroinoculation (SSA) method was established, and recombinant tobacco rattle virus vectors were constructed to express RNA interference (RNAi) inducers to cause virus-induced gene silencing (VIGS) in sunflower. A host target gene HaTubulin was systemically silenced in both leaf and root tissues by the SSA-VIGS approach. Trans-species silencing of O. cumana genes were confirmed for 10 out of 11 target genes with silencing efficiency of 23.43%-92.67%. Knockdown of target OcQR1, OcCKX5, and OcWRI1 genes reduced the haustoria number, and silencing of OcEXPA6 caused further phenotypic abnormalities such as shorter tubercles and necrosis. Overexpression of OcEXPA6 caused retarded root growth in alfalfa (Medicago sativa). The results demonstrate that these genes play an important role in the processes of O. cumana parasitism. High-throughput small RNA (sRNA) sequencing and bioinformatics analyses unveiled the distinct features of target gene-derived siRNAs in O. cumana such as siRNA transitivity, strand polarity, hotspot region, and 21/22-nt siRNA predominance, the latter of which was confirmed by Northern blot experiments. The possible RNAi mechanism is also discussed by analyzing RNAi machinery genes in O. cumana. Taken together, we established an efficient host-induced gene silencing technology for both functional genetics studies and potential control of O. cumana. The ease and effectiveness of this strategy could potentially be useful for other species provided they are amenable to SSA.
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http://dx.doi.org/10.1093/plphys/kiaa018DOI Listing
March 2021

High level expression and biochemical characterization of an alkaline serine protease from Geobacillus stearothermophilus to prepare antihypertensive whey protein hydrolysate.

BMC Biotechnol 2021 Mar 11;21(1):21. Epub 2021 Mar 11.

Key Laboratory of Food Bioengineering (China National Light Industry), College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua Donglu, Beijing, 100083, China.

Background: Proteases are important for hydrolysis of proteins to generate peptides with many bioactivities. Thus, the development of novel proteases with high activities is meaningful to discover bioactive peptides. Because natural isolation from animal, plant and microbial sources is impractical to produce large quantities of proteases, gene cloning and expression of target protease are preferred.

Results: In this study, an alkaline serine protease gene (GsProS8) from Geobacillus stearothermophilus was successfully cloned and expressed in Bacillus subtilis. The recombinant GsProS8 was produced with high protease activity of 3807 U/mL after high cell density fermentation. GsProS8 was then purified through ammonium sulfate precipitation and a two-step chromatographic method to obtain the homogeneous protease. The molecular mass of GsProS8 was estimated to be 27.2 kDa by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and 28.3 kDa by gel filtration. The optimal activity of GsProS8 was found to be pH 8.5 and 50 °C, respectively. The protease exhibited a broad substrate specificity and different kinetic parameters to casein and whey protein. Furthermore, the hydrolysis of whey protein using GsProS8 resulted in a large amount of peptides with high angiotensin-I-converting enzyme (ACE) inhibitory activity (IC of 0.129 mg/mL).

Conclusions: GsProS8 could be a potential candidate for industrial applications, especially the preparation of antihypertensive peptides.
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http://dx.doi.org/10.1186/s12896-021-00678-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7953746PMC
March 2021

Synbiotic yogurt containing konjac mannan oligosaccharides and Bifidobacterium animalis ssp. lactis BB12 alleviates constipation in mice by modulating the stem cell factor (SCF)/c-Kit pathway and gut microbiota.

J Dairy Sci 2021 Mar 1. Epub 2021 Mar 1.

Key Laboratory of Food Bioengineering (China National Light Industry), College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China. Electronic address:

Synbiotic dietary supplements, as an effective means of regulating the gut microbiota, may have a beneficial effect on constipation. This study evaluated the effects of synbiotic yogurt containing konjac mannan oligosaccharides (KMOS) and Bifidobacterium animalis ssp. lactis BB12 (BB12) on constipated Kunming mice (the model group). Following administration of yogurt containing 2.0% KMOS and BB12 (YBK2.0), black fecal weight and number and gastrointestinal transit rate increased by 97.5, 106.3, and 55.7%, respectively, compared with the model group. Serum levels of excitability neurotransmitters (motilin, substance P, and acetylcholine) in the YBK2.0 group were increased by 139.7, 120.4, and 91.8%, respectively, and serum levels of inhibitory neurotransmitters (vasoactive intestinal peptide, nitric oxide, and acetylcholine) were decreased. Moreover, synbiotic yogurt supplementation significantly downregulated the expression of vasoactive intestinal peptide receptor 1 (VIPR1) and upregulated the expression of serotonin receptor 4 (5-HT4) in the colon, and enhanced the expression of the stem cell factor (SCF)/c-Kit pathway. Additionally, YBK2.0 treatment significantly regulated the community composition and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of gut microbiota, which were positively correlated with physiological parameters of constipation. Thus, supplementation with synbiotic yogurt composed of KMOS and BB12 could facilitate fecal excretion by regulating related pathways and the gut microbiota. These findings demonstrated that the synbiotic yogurt can be considered a functional food for alleviating constipation.
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http://dx.doi.org/10.3168/jds.2020-19449DOI Listing
March 2021

Efficient production of a novel alkaline cold-active phospholipase C from Aspergillus oryzae by molecular chaperon co-expression for crude oil degumming.

Food Chem 2021 Jul 2;350:129212. Epub 2021 Feb 2.

College of Food Science and Nutrition Engineering, China Agriculture University, Beijing 100083, China; College of Engineering, China Agriculture University, Beijing 100083, China. Electronic address:

A novel alkaline cold-active phospholipase C (PLC) gene (AoPC) from Aspergillus oryzae was cloned. AoPC exhibited the highest sequence similarity of 32.5% with that of a PLC from Arabidopsis thaliana. The gene was co-expressed in Pichia pastoris with molecular chaperone PDI (protein disulfide isomerases), and the highest PLC activity of 82, 782 U mL was achieved in a 5-L fermentor. The recombinant enzyme (AoPC) was most active at pH 8.0 and 25 °C, respectively, and it was stable over a broad pH range of 4.5-9.0 and up to 40 °C. It is the first fungal alkaline PLC. The application of AoPC (with 25% citric acid, w/w) in oil degumming process significantly reduced the phosphorus of crude soybean oil by 93.3% to a commercially acceptable level (<10 mg kg). Therefore, the relatively high yield and excellent properties of AoPC may possess it great potential in crude oil refining industry.
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http://dx.doi.org/10.1016/j.foodchem.2021.129212DOI Listing
July 2021

Global transcriptomic analysis of functional oligosaccharide metabolism in Pediococcus pentosaceus.

Appl Microbiol Biotechnol 2021 Feb 29;105(4):1601-1614. Epub 2021 Jan 29.

Key Laboratory of Food Bioengineering (China National Light Industry), College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.

Lactic acid bacteria (LAB) are important in food fermentation and may enhance overall host health. Previous studies to explore LAB metabolism mainly focused on the genera Lacticaseibacillus and Lactococcus. Pediococcus pentosaceus, historically recognized as an important food fermentation bacterial strain, can produce bacteriocins and occasionally demonstrated probiotic functionalities. This study thoroughly surveyed the growth kinetic of three P. pentosaceus isolates in various culture formulations, especially in fructooligosaccharide (FOS), xylooligosaccharide (XOS), or konjac mannooligosaccharide (KMOS) conditions. Results showed that P. pentosaceus effectively metabolized KMOS, the culture of which led to 23.6-fold population increase. However, FOS and XOS were less metabolized by P. pentosaceus. On functional oligosaccharide cultures, P. pentosaceus could result in higher population proliferation, more acidified fermentation environment, and higher glycoside hydrolysis activities in the culture. RNA-Seq analysis classified 1572 out of 1708 putative genes as mRNA-coding genes. The dataset also revealed that the three functional oligosaccharides led to extensive global functional gene regulations. Phosphate conservation and utilization efficiency enhancement may serve as a leading transcriptional regulation direction in functional oligosaccharide metabolisms. In summary, these discovered metabolic characteristics could be employed to support future studies. KEY POINTS: • Konjac mannooligosaccharides effectively promoted P. pentosaceus proliferation. • Functional genes were highly regulated in functional oligosaccharide utilization. • Phosphate conservation was an important transcriptional regulation direction.
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http://dx.doi.org/10.1007/s00253-021-11120-5DOI Listing
February 2021

Biochemical Properties of a Novel D-Mannose Isomerase from Pseudomonas syringae for D-Mannose Production.

Appl Biochem Biotechnol 2021 Jan 23. Epub 2021 Jan 23.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Engineering, China Agricultural University, No.17 Qinghua Donglu, Haidian District, Beijing, 100083, China.

D-Mannose isomerase can reversibly catalyze D-fructose to D-mannose which has various beneficial effects. A novel D-mannose isomerase gene (PsMIaseA) from Pseudomonas syringae was cloned and expressed in Escherichia coli. The recombinant D-mannose isomerase (PsMIaseA) showed the highest amino acid sequence homogeneity of 50% with ManI from Thermobifda fusca. PsMIaseA was purified through Ni-NTA chromatography, and its specific activity was 818.6 U mg. The optimal pH and temperature of PsMIaseA were pH 7.5 and 45 °C, respectively. The enzyme was stable within a wide pH range from 5.0 to 10.0. It could efficiently convert D-fructose to D-mannose without any metal ions. When PsMIaseA was incubated with 600 g/L D-fructose for 6 h, the space-time yield of D-mannose reached 27.2 g L h with a maximum conversion ratio of 27%. Therefore, the D-mannose isomerase may be suitable for green production of D-mannose.
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http://dx.doi.org/10.1007/s12010-021-03487-yDOI Listing
January 2021

Alginate Oligosaccharides: Production, Biological Activities, and Potential Applications.

Compr Rev Food Sci Food Saf 2019 Nov 19;18(6):1859-1881. Epub 2019 Sep 19.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural Univ., Beijing, 100083, China.

Alginate, a group of polyuronic saccharides, has been widely used in both pharmaceutical and food industries due to its unique physicochemical properties as well as beneficial health effects. However, the potential applications of alginate are restricted because of its low water solubility and high solution viscosity when significant concentrations are needed, particularly in food products. Alginate oligosaccharides (AOS), oligomers containing 2 to 25 monomers, can be obtained via hydrolysis of glycosidic bonds, organic synthesis, or through biosynthesis. Generally, AOS have shorter chain lengths and thus improved water solubility when compared with higher molecular weight alginates of the same monomers. These oligosaccharides have attracted interest from both basic and applied researchers. AOS have unique bioactivity and can impart health benefits. They have shown immunomodulatory, antimicrobial, antioxidant, prebiotic, antihypertensive, antidiabetic, antitumor, anticoagulant, and other activities. As examples, they have been utilized as prebiotics, feed supplements for aquaculture, poultry, and swine, elicitors for plants and microorganisms, cryoprotectors for frozen foods, and postharvest treatments. This review comprehensively covers methods for AOS production from alginate, such as physical/chemical methods, enzymatic methods, fermentation, organic synthesis, and biosynthesis. Moreover, current progress in structural characterization, potential health benefits, and AOS metabolism after ingestion are summarized in this review. This review will discuss methods for producing and modified AOS with desirable structures that are suited for novel applications.
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http://dx.doi.org/10.1111/1541-4337.12494DOI Listing
November 2019

High-level expression and enzymatic properties of a novel thermostable xylanase with high arabinoxylan degradation ability from Chaetomium sp. suitable for beer mashing.

Int J Biol Macromol 2021 Jan 9;168:223-232. Epub 2020 Dec 9.

College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China. Electronic address:

A novel thermostable xylanase gene from Chaetomium sp. CQ31 was cloned and codon-optimized (CsXynBop). The deduced protein sequence of the gene shared the highest similarity of 75% with the glycoside hydrolase (GH) family 10 xylanase from Achaetomium sp. Xz-8. CsXynBop was over-expressed in Pichia pastoris GS115 by high-cell density fermentation, with the highest xylanase yield of 10,017 U/mL. The recombinant xylanase (CsXynBop) was purified to homogeneity and biochemically characterized. CsXynBop was optimally active at pH 6.5 and 85 °C, respectively, and stable over a broad pH range of 5.0-9.5 and up to 60 °C. The enzyme exhibited strict substrate specificity towards oat-spelt xylan (2, 489 U/mg), beechwood xylan (1522 U/mg), birchwood xylan (1067 U/mg), and showed relatively high activity towards arabinoxylan (1208 U/mg), but exhibited no activity on other tested polysaccharides. CsXynBop hydrolyzed different xylans to yield mainly xylooligosaccharides (XOSs) with degree of polymerization (DP) 2-5. The application of CsXynBop (200 U/g malt) in malt mashing substantially decreased the filtration time and viscosity of malt by 42.3% and 8.6%, respectively. These excellent characteristics of CsXynBop may make it a good candidate in beer industry.
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http://dx.doi.org/10.1016/j.ijbiomac.2020.12.040DOI Listing
January 2021

Biochemical characterization of a novel α-L-fucosidase from Pedobacter sp. and its application in synthesis of 3'-fucosyllactose and 2'-fucosyllactose.

Appl Microbiol Biotechnol 2020 Jul 9;104(13):5813-5826. Epub 2020 May 9.

Key Laboratory of Food Bioengineering (China National Light Industry), College of Food Science and Nutritional Engineering, China Agricultural University, No.17 Qinghua Donglu, Haidian District, Beijing, 100083, China.

Fucosyllactoses have gained much attention owing to their multiple functions, including prebiotic, immune, gut, and cognition benefits. In this study, human milk oligosaccharide (HMO) 2'-fucosyllactose (α-L-Fuc-(1,2)-D-Galβ-1,4-Glu, 2'FL) and its isomer 3'-fucosyllactose (α-L-Fuc-(1,3)-D-Galβ-1,4-Glu, 3'FL) with potential prebiotic effect were synthesized efficiently by a novel recombinant α-L-fucosidase. An α-L-fucosidase gene (PbFuc) from Pedobacter sp. CAU209 was successfully cloned and expressed in Escherichia coli (E. coli). The deduced amino acid sequence shared the highest identity of 36.8% with the amino sequences of other reported α-L-fucosidases. The purified α-L-fucosidase (PbFuc) had a molecular mass of 50 kDa. The enzyme exhibited specific activity (26.3 U/mg) towards 4-nitrophenyl-α-L-fucopyranoside (pNP-FUC), 3'FL (8.9 U/mg), and 2'FL (3.4 U/mg). It showed the highest activity at pH 5.0 and 35 °C, respectively. PbFuc catalyzed the synthesis of 3'FL and 2'FL through a transglycosylation reaction using pNP-FUC as donor and lactose as acceptor, and total conversion ratio was up to 85% at the optimized reaction conditions. The synthesized mixture of 2'FL and 3'FL promoted the growth of Lactobacillus delbrueckii subsp. bulgaricus NRRL B-548, L. casei subsp. casei NRRL B-1922, L. casei subsp. casei AS 1.2435, and Bifidobacterium longum NRRL B-41409. However, the growths of E. coli ATCC 11775, S. enterica AS 1.1552, L. monocytogenes CICC 21635, and S. aureus AS 1.1861 were not stimulated by the mixture of 2'FL and 3'FL. Overall, our findings suggest that PbFuc possesses a great potential for the specific synthesis of fucosylated compounds.Key Points• A novel α-L-fucosidase (PbFuc) from Pedobacter sp. was cloned and expressed.• PbFuc showed the highest hydrolysis activity at pH 5.0 and 35 °C, respectively.• It was used for synthesis of 3'-fucosyllactose (3'FL) and 2'-fucosyllactose (2'FL).• The mixture of 3'FL and 2'FL promoted the growth of some Lactobacillus sp. and Bifidobacteria sp.
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http://dx.doi.org/10.1007/s00253-020-10630-yDOI Listing
July 2020

Structural basis of carbohydrate binding in domain C of a type I pullulanase from Paenibacillus barengoltzii.

Acta Crystallogr D Struct Biol 2020 May 23;76(Pt 5):447-457. Epub 2020 Apr 23.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, People's Republic of China.

Pullulanase (EC 3.2.1.41) is a well known starch-debranching enzyme that catalyzes the cleavage of α-1,6-glycosidic linkages in α-glucans such as starch and pullulan. Crystal structures of a type I pullulanase from Paenibacillus barengoltzii (PbPulA) and of PbPulA in complex with maltopentaose (G5), maltohexaose (G6)/α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD) were determined in order to better understand substrate binding to this enzyme. PbPulA belongs to glycoside hydrolase (GH) family 13 subfamily 14 and is composed of three domains (CBM48, A and C). Three carbohydrate-binding sites identified in PbPulA were located in CBM48, near the active site and in domain C, respectively. The binding site in CBM48 was specific for β-CD, while that in domain C has not been reported for other pullulanases. The domain C binding site had higher affinity for α-CD than for G6; a small motif (FGGEH) seemed to be one of the major determinants for carbohydrate binding in this domain. Structure-based mutations of several surface-exposed aromatic residues in CBM48 and domain C had a debilitating effect on the activity of the enzyme. These results suggest that both CBM48 and domain C play a role in binding substrates. The crystal forms described contribute to the understanding of pullulanase domain-carbohydrate interactions.
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http://dx.doi.org/10.1107/S205979832000409XDOI Listing
May 2020

Biochemical Characterization and Structural Analysis of a β--Acetylglucosaminidase from for Efficient Production of -Acetyl-d-glucosamine.

J Agric Food Chem 2020 May 11;68(20):5648-5657. Epub 2020 May 11.

College of Food Science and Nutritional Engineering, China Agricultural University, No.17 Qinghua East Road, Haidian District, Beijing 100083, China.

Bioproduction of -acetyl-d-glucosamine (GlcNAc) from chitin, the second most abundant natural renewable polymer on earth, is of great value in which chitinolytic enzymes play key roles. In this study, a novel glycoside hydrolase family-18 β--acetylglucosaminidase (PbNag39) from suitable for GlcNAc production was identified and biochemically characterized. It possessed a unique shallow catalytic groove (5.8 Å) as well as a smaller C-terminal domain (solvent-accessible surface area, 5.1 × 10 Å) and exhibited strict substrate specificity toward -acetyl chitooligosaccharides (COS) with GlcNAc as the sole product, showing a typical manner of action of β--acetylglucosaminidases. Thus, an environmentally friendly bioprocess for GlcNAc production from ball-milled powdery chitin by an enzyme cocktail reaction was further developed. By using the new route, the powdery chitin conversion rate increased from 23.3% (v/v) to 75.3% with a final GlcNAc content of 22.6 mg mL. The efficient and environmentally friendly bioprocess may have great application potential in GlcNAc production.
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http://dx.doi.org/10.1021/acs.jafc.9b08085DOI Listing
May 2020

High-level expression and characterization of a novel phospholipase C from Thielavia terrestris suitable for oil degumming.

Int J Biol Macromol 2020 Aug 18;156:740-748. Epub 2020 Apr 18.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agriculture University, Beijing 100083, China. Electronic address:

A novel phospholipase C gene (TtPLC) from Thielavia terrestris CAU709 was cloned and efficiently expressed in Pichia pastoris. The deduced protein sequence of TtPLC shared the highest identity of 33% with the characterized phospholipase C from Arabidopsis thaliana. The highest phospholipase C yield of 98, 970 U mL, with a protein concentration of 4.9 mg mL was obtained by high-cell density fermentation in a 5-L fermentor. The recombinant enzyme (TtPLC) was purified to homogeneity with a recovery yield of 59.1% and a specific activity of 22, 910 U mg. TtPLC was most active at pH 6.5 and 55 °C, respectively. It was stable within the pH range of 4.5-8.0 and up to 45 °C. The enzyme exhibited excellent stability in different surfactants and organic solvents, including Tween 20 (147.6%), Tween 40 (180.6%), Tween 60 (205.4%), cyclohexane (160.0%), n-octane (178.2%), n-heptane (180.7%), acetone (187.5%) etc. The application of TtPLC in crude soybean oil degumming process significantly reduced the residual phosphorus content from 135.4 mg kg to 7.9 mg kg under the optimized conditions, which satisfied the requirement of environmental friendly physical refining process for oil refining industry. Therefore, TtPLC should be a good candidate in oil refining industry.
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http://dx.doi.org/10.1016/j.ijbiomac.2020.04.104DOI Listing
August 2020

Biochemical characterization of a bifunctional chitinase/lysozyme from Streptomyces sampsonii suitable for N-acetyl chitobiose production.

Biotechnol Lett 2020 Aug 13;42(8):1489-1499. Epub 2020 Mar 13.

Key Laboratory of Food Bioengineering (China National Light Industry), College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China.

Objectives: Chitinases play important role in chitin bioconversion, while few of them have been put into use due to their poor properties. We aimed to identify and characterize chitinases suitable for N-acetyl chitooligosaccharides (COSs) production from chitin materials.

Results: A chitinase gene (SsChi28) from Streptomyces sampsonii XY2-7 was cloned and heterologously expressed in E. coli BL21 (DE3) as an active protein. The deduced protein shared high sequence identities and structure similarities with some glycoside hydrolase family 19 chitinases. The recombinant enzyme (SsChi28) was purified and biochemically characterized. SsChi28 was a monomeric protein with a molecular mass of 30 kDa estimated by SDS-PAGE. It was most active at pH 6.0 and 55 °C, respectively, and stable in a wide pH range of 3.5-11.5 and up to 60 °C. The enzyme exhibited strict substrate specificities towards ethylene glycol chitin (222.3 U/mg) and colloidal chitin (20.1 U/mg). Besides, it displayed lysozyme activity against Micrococcus lysodeikticus. SsChi28 hydrolyzed colloidal chitin to yield mainly N-acetyl chitobiose, accounting high up to 73% (w/w) in total products.

Conclusion: The excellent enzymatic properties of SsChi28 may make it potential in chitin bioconversion (especially for N-acetyl COS production), as well as in biological control of fungal diseases.
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http://dx.doi.org/10.1007/s10529-020-02834-zDOI Listing
August 2020

Curdlan () (1→3)-β-d-Glucan Oligosaccharides Drive M1 Phenotype Polarization in Murine Bone Marrow-Derived Macrophages via Activation of MAPKs and NF-κB Pathways.

Molecules 2019 Nov 22;24(23). Epub 2019 Nov 22.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.

Functional oligosaccharides, particularly curdlan (1→3)-β-d-glucan oligosaccharides (GOS), play important roles in modulating host immune responses. However, the molecular mechanisms underlying the immunostimulatory effects of GOS on macrophage polarization are not clear. In this work, GOS (5-1000 µg/mL) were non-toxic to bone marrow-derived macrophages (BMDMs) with improved pinocytic and bactericidal capacities. Incubation with GOS (100 µg/mL) induced M1 phenotype polarization of BMDMs as evidenced by increased CD11c/CD86 (10.1%) and M1 gene expression of inducible nitric oxide synthase, interleukin (IL)-1β, and chemokine C-C-motif ligand 2. Accordingly, the secretion of cytokines IL-1β, IL-6, monocyte chemotactic protein-1, and tumor necrosis factor-α, as well as the nitrite release of BMDMs were increased by GOS (100 µg/mL). Expression of mitogen-activated protein kinases (MAPKs) of phosphorylated (p)-c-Jun amino-terminal kinase, p-extracellular signal regulated kinase, and p-p38 in BMDMs were increased by GOS, as well as the p-Stat1. Moreover, nuclear factor-kappa B (NF-κB) p-p65 expression in BMDMs was promoted by GOS while it suppressed IκBα expression. Receptor blocking with anti-CR3 (CD11b/CD18) and anti-toll-like receptor (TLR) 2 antibodies diminished GOS induced M1 phenotype polarization with reduced mRNA expression of M1 genes, decreased cytokine and nitrite releases, and suppressed signaling pathway activation. Thus, CR3 (CD11b/CD18) and TLR2 mediated activation of MAPKs and NF-κB pathways are responsible for GOS induced polarization of BMDMs.
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http://dx.doi.org/10.3390/molecules24234251DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6930549PMC
November 2019

Partially Hydrolyzed Guar Gum Attenuates d-Galactose-Induced Oxidative Stress and Restores Gut Microbiota in Rats.

Int J Mol Sci 2019 Sep 30;20(19). Epub 2019 Sep 30.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.

Partially hydrolyzed guar gum (PHGG) has received considerable attention for its various bioactive functions. The injection of d-galactose can cause aging-related injury which is usually resulted from oxidative stress on tissues and cells. In this study, d-galactose (200 mg/kg/day) was injected into rats, and the protective effects of PHGG (500, 1000, and 1500 mg/kg/day) against oxidative damages, as well as its probiotic functions, were analyzed. The results showed that PHGG treatment at a concentration of 1500 mg/kg/day greatly reduced the levels of lactic acid, nitric oxide, inducible nitric oxide synthase, advanced glycation end products, and increased the telomerase activity, by 7.60%, 9.25%, 12.28%, 14.58%, and 9.01%, respectively. Moreover, PHGG significantly elevated the activities of antioxidant enzymes and decreased the content of malondialdehyde in rat serum and brain. The oxidative damage was also significantly alleviated in the liver and hippocampus and the expressions of brain-derived neurotrophic factor and choline acetyltransferase also increased. Furthermore, PHGG treatment could significantly regulated the expression of sirtuin 1, forkhead box O1, and tumor protein p53 in the hippocampus. It also increased the levels of organic acids and improved the composition of intestinal microbiota. These findings demonstrated that PHGG treatment could effectively alleviate the oxidative damage and dysbacteriosis.
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http://dx.doi.org/10.3390/ijms20194861DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6801633PMC
September 2019

Can functional oligosaccharides reduce the risk of diabetes mellitus?

FASEB J 2019 11 15;33(11):11655-11667. Epub 2019 Aug 15.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.

Diabetes significantly affects the life quality and length of patients with diabetes, and almost half of the 4 million people who die from diabetes are under the age of 60. Because of the increasing number of patients with diabetes and the side effects of antidiabetic drugs, the search for new dietary supplementation from natural resources, especially functional oligosaccharides, has attracted much attention among scientific researchers. Functional oligosaccharides are potential antidiabetic treatments because of their nondigestible, low-calorie, and probiotic features. The antidiabetic activity of multiple functional oligosaccharides such as fructo-oligosaccharides, galacto-oligosaccharides, and xylo-oligosaccharides has been reviewed in this paper. Molecular mechanisms involved in the antidiabetic activity of oligosaccharides have been systematically discussed from multiple perspectives, including the improvement of pancreas function, α-glucosidase inhibition, the relief of insulin and leptin resistance, anti-inflammatory effects, regulation of gut microbiota and hormones, and the intervention of diabetic risk factors. In addition, the antidiabetic effects of functional oligosaccharides through the complex gut-brain-liver axis are summarized. The concepts addressed in this review have important clinical implications, although more works are needed to confirm the antidiabetic mechanisms of functional oligosaccharides, standardize safe dose levels, and clarify their metabolism in the human body.-Zhu, D., Yan, Q., Liu, J., Wu, X., Jiang, Z. Can functional oligosaccharides reduce the risk of diabetes mellitus?
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http://dx.doi.org/10.1096/fj.201802802RRRDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6902710PMC
November 2019

Biochemical characterization of a novel exo-oligoxylanase from suitable for monosaccharification from corncobs.

Biotechnol Biofuels 2019 29;12:190. Epub 2019 Jul 29.

1Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Engineering, China Agricultural University, Beijing, 100083 China.

Background: Xylan is the major component of hemicelluloses, which are the second most abundant polysaccharides in nature, accounting for approximately one-third of all renewable organic carbon resources on earth. Efficient degradation of xylan is the prerequisite for biofuel production. Enzymatic degradation has been demonstrated to be more attractive due to low energy consumption and environmental friendliness, when compared with chemical degradation. Exo-xylanases, as a rate-limiting factor, play an important role in the xylose production. It is of great value to identify novel exo-xylanases for efficient bioconversion of xylan in biorefinery industry.

Results: A novel glycoside hydrolase (GH) family 8 reducing-end xylose-releasing exo-oligoxylanase (Rex)-encoding gene () was cloned from and heterogeneously expressed in . The deduced amino acid sequence of shared the highest identity of 74% with a Rex from The recombinant enzyme (PbRex8) was purified and biochemically characterized. The optimal pH and temperature of PbRex8 were 5.5 and 55 °C, respectively. PbRex8 showed prominent activity on xylooligosaccharides (XOSs), and trace activity on xylan. It also exhibited β-1,3-1,4-glucanase and xylobiase activities. The enzyme efficiently converted corncob xylan to xylose coupled with a GH family 10 endo-xylanase, with a xylose yield of 83%. The crystal structure of PbRex8 was resolved at 1.88 Å. Structural comparison suggests that Arg67 can hydrogen-bond to xylose moieties in the -1 subsite, and Asn122 and Arg253 are close to xylose moieties in the -3 subsite, the hypotheses of which were further verified by mutation analysis. In addition, Trp205, Trp132, Tyr372, Tyr277 and Tyr369 in the grove of PbRex8 were found to involve in glucooligosaccharides interactions. This is the first report on a GH family 8 Rex from .

Conclusions: A novel reducing-end xylose-releasing exo-oligoxylanase suitable for xylose production from corncobs was identified, biochemically characterized and structurally elucidated. The properties of PbRex8 may make it an excellent candidate in biorefinery industries.
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http://dx.doi.org/10.1186/s13068-019-1532-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6661730PMC
July 2019

Effect of Konjac Mannan Oligosaccharides on Glucose Homeostasis via the Improvement of Insulin and Leptin Resistance In Vitro and In Vivo.

Nutrients 2019 Jul 24;11(8). Epub 2019 Jul 24.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing 100083, China.

Functional oligosaccharides, particularly konjac mannan oligosaccharides (KMOS), can regulate glucose metabolism. However, the molecular mechanisms involved in the hypoglycemic effect of KMOS remain largely unknown. Here, the effect of KMOS supplementation on glucose homeostasis was evaluated in both high-fat diet (HFD)-fed C57BL/6J mice and high-glucosamine-induced HepG2 cells. KMOS supplementation remarkably ameliorated the fasting blood glucose, glucose tolerance, and insulin tolerance of HFD-fed mice. Abnormalities of triglyceride and glycogen metabolism in the liver induced by the HFD were reversed by KMOS supplementation. The insulin signaling pathway was activated by KMOS, with stimulation of GLUT2 membrane translocation and glucose uptake in HepG2 cells via the AMPK pathway. Moreover, KMOS suppressed p-mTOR expression and stimulated the GSK-3β/CREB pathway via the AMPK pathway. KMOS significantly upregulated leptin receptor expression and downregulated PTP1B and SOCS3 levels in the liver and brain, with a decreased serum leptin concentration. Phosphorylation of JAK2 and STAT3 in the liver was activated by KMOS supplementation, while the expressions of Sirt1, Tfam, and Pgc1-α in the brain were elevated. Conclusively, KMOS attenuated HFD-induced glucose metabolism dysfunction through the regulation of insulin resistance and leptin resistance. This finding indicates that KMOS have potential value as an anti-hyperglycemic dietary supplement.
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http://dx.doi.org/10.3390/nu11081705DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6723648PMC
July 2019

Biochemical characterization of a novel lipase from Malbranchea cinnamomea suitable for production of lipolyzed milkfat flavor and biodegradation of phthalate esters.

Food Chem 2019 Nov 31;297:124925. Epub 2019 May 31.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China. Electronic address:

A novel lipase gene (McLipB) was cloned from a thermophilic fungus Malbranchea cinnamomea and expressed in Pichia pastoris. The deduced amino acid sequence of the lipase (McLipB) shared the highest identity of 46% with the Candida rugosa lipase LIP4. The extracellular lipase activity of 4304 U/mL with protein concentration of 7.7 mg/mL was achieved in a 5-L fermentor. The optimal pH and temperature of McLipB were 7.5 and 40 °C, respectively. The lipase showed high specificity towards triglycerides with short and medium chain fatty acids, and had non-position specificity. McLipB hydrolyzed butter to produce mainly butyric acid, hexanoic acid and a small amount of octanoic acid and decanoic acid. Furthermore, it degraded more than 90% dipropyl phthalate, dibutyl phthalate and dihexyl phthalate to their corresponding monoalkyl phthalates. The properties of McLipB indicate that it has great application potential for production of lipolyzed milkfat flavor and biodegradation of phthalate esters.
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http://dx.doi.org/10.1016/j.foodchem.2019.05.199DOI Listing
November 2019

High-level expression of codon-optimized Thielavia terrestris cutinase suitable for ester biosynthesis and biodegradation.

Int J Biol Macromol 2019 Aug 23;135:768-775. Epub 2019 May 23.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing 100083, China; College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China. Electronic address:

A codon-optimized cutinase gene (TtCutopt) from Thielavia terrestris was over-expressed in Pichia pastoris. An extracellular activity reached 10,200 U/mL using high cell density fermentation. The optimal pH and temperature of TtCutopt were 7.0 and 50 °C, respectively. It displayed high stability over a wide range of pH from 3.0 to 11.0 and up to 85 °C. Among tested p-nitrophenyl esters and triglycerides, TtCutopt showed the highest activity towards p-nitrophenyl butyrate and tributyrin, with specificity activity of 2322.4 U/mg and 1152.5 U/mg, respectively. It was extremely stable in organic solvents and surfactants. TtCutopt efficiently catalyzed the synthesis of butyl butyrate, hexyl butyrate, butyl hexanoate and hexyl hexanoate with esterification efficiency of >95%. Furthermore, it catalyzed the degradation of >90% of dimethyl phthalate, diethyl phthalate, dipropyl phthalate and dibutyl phthalate to release their corresponding monoalkyl phthalates within 24 h. Thus, high yield, high stability, and esterification efficiency of TtCutopt make it an attractive candidate for ester biosynthesis and biodegradation.
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http://dx.doi.org/10.1016/j.ijbiomac.2019.05.173DOI Listing
August 2019

Hepatoprotective Potential of Partially Hydrolyzed Guar Gum against Acute Alcohol-Induced Liver Injury in Vitro and Vivo.

Nutrients 2019 Apr 27;11(5). Epub 2019 Apr 27.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing 100083, China.

Natural polysaccharides, particularly galactomannans, are potential candidates for treatment of alcoholic liver diseases (ALD). However, applications are restricted due to the physicochemical properties associated with the high molecular weight. In this work, guar gum galactomannans were partially hydrolyzed by β-mannanase, and the molecular mechanisms of hepatoprotective effects were elucidated both in vitro and in vivo. Release of lactate dehydrogenase and cytochrome C were attenuated by partially hydrolyzed guar gum (PHGG) in HepG2 cells, due to protected cell and mitochondrial membrane integrity. PHGG co-administration decreased serum amino transaminases and cholinesterase levels of acute alcohol intoxicated mice, while hepatic pathologic morphology was depleted. Activity of superoxide dismutase, catalase, and glutathione peroxidase was recovered to 198.2, 34.5, 236.0 U/mg protein, respectively, while malondialdehyde level was decreased by 76.3% (PHGG, 1000 mg/kg∙day). Co-administration of PHGG induced a 4.4-fold increment of p-AMPK expression, and lipid metabolism was mediated. PHGG alleviated toll-like-receptor-4-mediated inflammation via the signaling cascade of MyD88 and IκBα, decreasing cytokine production. Moreover, mediated expression of Bcl-2 and Bax was responsible for inhibited acute alcohol-induced apoptosis with suppressed cleavage of caspase 3 and PARP. Findings gained suggest that PHGG can be used as functional food supplement for the treatment of acute alcohol-induced liver injury.
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http://dx.doi.org/10.3390/nu11050963DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6567107PMC
April 2019

Xylose rich heteroglycan from flaxseed gum mediates the immunostimulatory effects on macrophages via TLR2 activation.

Carbohydr Polym 2019 Jun 23;213:59-69. Epub 2019 Feb 23.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China. Electronic address:

Immunostimulatory activity of the flaxseed gum neutral fraction (NFG) was investigated. NFG was characterized as a xylose rich heteroglycan through monosaccharide composition analysis, FT-IR, methylation/GC-MS, and 1D/2D-NMR. NFG stimulated NO production and phagocytic activity of macrophages. Secretion of interleukin-6, interleukin-1β, and tumor necrosis factor-α (254.7 pg/mL, 2.5 ng/mL, and 42.9 pg/mL, respectively) was significantly induced by NFG. Mitogen-activated protein kinases of JNK and P38 were activated by NFG with increased phosphorylation of JNK and P38, while NO production was reduced to 6.05 and 4.42 μM by JNK and P38 inhibitor, respectively. Nuclear factor-κB signaling pathway was also activated by NFG with the suppression of IκBα and up-regulation of phosphorylation of IκBα and nuclear factor-κB P65. Toll like receptor-2 was the molecular target of NFG and responsible for the activation of down-stream signaling pathways. Thus, NFG from flaxseed gum may potentially be used as a natural immunomodulator in functional foods.
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http://dx.doi.org/10.1016/j.carbpol.2019.02.080DOI Listing
June 2019

Curdlan oligosaccharides having higher immunostimulatory activity than curdlan in mice treated with cyclophosphamide.

Carbohydr Polym 2019 Mar 22;207:131-142. Epub 2018 Nov 22.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua Donglu, Haidian District, Beijing, 100083, China. Electronic address:

This study evaluated the immunostimulatory activity of curdlan oligosaccharides (GOS) in cyclophosphamide (CTX)-induced immunosuppressed mice and in RAW264.7 cells. GOS was able to stimulate the release of nitric oxide (NO), cytokines (IL-1β, IL-6 and TNF-α) and improve the phagocytic rate of peritoneal macrophages and RAW264.7 cells. It further enhanced immunoglobulins (Ig) release (IgG by 50.6%-74.7%, IgA by 31.3%-34.9%, IgM by 28.3%-66.7%), splenic lymphocyte proliferation (by 74.8%-91.3%), nature killer cells cytotoxicity (by 32.0%-49.6%), immunophenotypes of splenic lymphocytes (from 1.7 to 2.4, 2.2 and 2.7) in immunosuppressed mice. Compared with curdlan, higher immunostimulatory activity of GOS was found in CTX-treated mice. Moreover, GOS could activate nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways through toll-like receptor 2 (TLR2) and complement receptor 3 (CR3). These results indicated that GOS may be a favorable candidate of functional food in regulating immune responses.
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http://dx.doi.org/10.1016/j.carbpol.2018.10.120DOI Listing
March 2019

Slightly Acidic Electrolyzed Water Treatment Enhances the Main Bioactive Phytochemicals Content in Broccoli Sprouts via Changing Metabolism.

J Agric Food Chem 2019 Jan 8;67(2):606-614. Epub 2019 Jan 8.

Beijing Advanced Innovation Center for Food Nutrition and Human Health , China Agricultural University , Beijing 100083 , China.

Changes in the content of bioactive phytochemicals in the broccoli sprouts subjected to different slightly acidic electrolyzed water (SAEW) treatments were investigated in the present study. The highest sulforaphane amount in broccoli sprouts treated with SAEW with an available chlorine concentration (ACC) of 50 mg/L was 11.49 mg/g in dry weight (DW), which increased by 61.2% compared to the control. SAEW treatment enhanced the sulforaphane content mainly by increasing the glucoraphanin (GRA) concentration due to the promotion of methionine metabolism and increased myrosinase activities. In addition, the relative anthocyanin contents of light-germinated broccoli under SAEW 50 treatment were 2.03 times that of broccoli sprouts with tap water treatment, and these contents were associated with an increase in phenylalanine ammonia lyase (PAL) activities and phenylalanine participation in biosynthesis. In summary, SAEW promotes metabolism to induce the accumulation of bioactive compounds in broccoli sprouts.
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http://dx.doi.org/10.1021/acs.jafc.8b04958DOI Listing
January 2019

A novel thermostable β-1,3-1,4-glucanase from Thermoascus aurantiacus and its application in oligosaccharide production from oat bran.

Carbohydr Res 2018 Nov 5;469:31-37. Epub 2018 Sep 5.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing, 100083, China; College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China. Electronic address:

Fermentation conditions for β-1,3-1,4-glucanase (TaGlu34) production in submerged culture by a thermophilic fungus, Thermoascus aurantiacus CAU830 were optimized. The highest enzyme activity of 3741 U/mL was obtained, and the crude enzyme was purified to homogeneity with a purification fold of 7.3 and a recovery yield of 11.6%. The molecular mass of the purified enzyme was estimated to be approximately 34 kDa on SDS-PAGE. TaGlu34 was most active at pH 6.0 and 75 °C, respectively. It showed excellent thermostability with thermal denaturing half-lives of 209, 130 and 69 min at 50, 60 and 70 °C, respectively. TaGlu34 exhibited strict substrate specificity towards barley β-glucan (13,527 U/mg), oat β-glucan (12,502 U/mg) and lichenan (9225 U/mg), but displayed no activity on other tested polysaccharides including laminarin, xylan, pullulan, CMC and starch. TaGlu34 hydrolyzed barley β-glucan and lichenan to yield both mainly disaccharide and trisaccharide, suggesting that it should be an endo type β-1,3-1,4-glucanase. Furthermore, TaGlu34 efficiently degraded the β-glucan component in oat bran to produce mainly oligosaccharides with degrees of polymerization (DP) 3-5, with the highest conversion ratio of 47.1%. The high yield and excellent enzymatic properties of TaGlu34 may make it a good candidate in industries.
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http://dx.doi.org/10.1016/j.carres.2018.08.017DOI Listing
November 2018

Multiple Pedestrian Tracking From Monocular Videos in an Interacting Multiple Model Framework.

IEEE Trans Image Process 2018 Mar 4;27(3):1361-1375. Epub 2017 Dec 4.

We present a multiple pedestrian tracking method for monocular videos captured by a fixed camera in an interacting multiple model (IMM) framework. Our tracking method involves multiple IMM trackers running in parallel, which are tied together by a robust data association component. We investigate two data association strategies which take into account both the target appearance and motion errors. We use a 4D color histogram as the appearance model for each pedestrian returned by a people detector that is based on the histogram of oriented gradients features. Short-term occlusion problems and false negative errors from the detector are dealt with using a sliding window of video frames, where tracking persists in the absence of observations. Our method has been evaluated, and compared both qualitatively and quantitatively with four state-of-the-art visual tracking methods using benchmark video databases. The experiments demonstrate that, on average, our tracking method outperforms these four methods.
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http://dx.doi.org/10.1109/TIP.2017.2779856DOI Listing
March 2018

Structural insights into the catalytic mechanism of a novel glycoside hydrolase family 113 β-1,4-mannanase from .

J Biol Chem 2018 07 5;293(30):11746-11757. Epub 2018 Jun 5.

the College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China

β-1,4-Mannanase degrades β-1,4-mannan polymers into manno-oligosaccharides with a low degree of polymerization. To date, only one glycoside hydrolase (GH) family 113 β-1,4-mannanase, from (ManA), has been structurally characterized, and no complex structure of enzyme-manno-oligosaccharides from this family has been reported. Here, crystal structures of a GH family 113 β-1,4-mannanase from (Man113A) and its complexes with mannobiose, mannotriose, mannopentaose, and mannahexaose were solved. Man113A had higher affinity for -1 and +1 mannoses, which explains why the enzyme can hydrolyze mannobiose. At least six subsites (-4 to +2) exist in the groove, but mannose units preferentially occupied subsites -4 to -1 because of steric hindrance formed by Lys-238 and Trp-239. Based on the structural information and bioinformatics, rational design was implemented to enhance hydrolysis activity. Enzyme activity of Man113A mutants V139C, N237W, K238A, and W239Y was improved by 93.7, 63.4, 112.9, and 36.4%, respectively, compared with the WT. In addition, previously unreported surface-binding sites were observed. Site-directed mutagenesis studies and kinetic data indicated that key residues near the surface sites play important roles in substrate binding and recognition. These first GH family 113 β-1,4-mannanase-manno-oligosaccharide complex structures may be useful in further studying the catalytic mechanism of GH family 113 members, and provide novel insight into protein engineering of GHs to improve their hydrolysis activity.
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http://dx.doi.org/10.1074/jbc.RA118.002363DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6066303PMC
July 2018

Biochemical characterization of a novel xylanase from Paenibacillus barengoltzii and its application in xylooligosaccharides production from corncobs.

Food Chem 2018 Oct 6;264:310-318. Epub 2018 May 6.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Engineering, China Agricultural University, Beijing 100083, China. Electronic address:

A novel xylanase gene (PbXyn10A) from Paenibacillus barengoltzii was cloned and expressed in Escherichia coli. PbXyn10A had an open reading frame of 3,063 bp, and its deduced amino acid sequence shared the highest identity of 72% with a xylanase from Paenibacillus curdlanolyticus. The recombinant xylanase (PbXyn10A) was purified and biochemically characterized. PbXyn10A was most active at pH 6.5 and 60 °C, respectively. It exhibited strict substrate specificity towards birchwood xylan, beechwood xylan and oat-spelt xylan, with K values of 2.19, 2.04 and 2.51 mg/mL, respectively. The enzyme hydrolyzed xylan to yield mainly xylooligosaccharides (XOS) with degree of polymerization 2-4. A new strategy for XOS production from corncobs pretreated by steam explosion using acidic electrolyzed water, followed by enzymatic hydrolysis was developed. The highest XOS yield of 75% (based on xylan in raw corncobs) was achieved. This is the first report on a xylanase from Paenibacillus barengoltzii.
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http://dx.doi.org/10.1016/j.foodchem.2018.05.023DOI Listing
October 2018

In vitro digestibility and prebiotic potential of curdlan (1 → 3)-β-d-glucan oligosaccharides in Lactobacillus species.

Carbohydr Polym 2018 May 31;188:17-26. Epub 2018 Jan 31.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, No.17 Qinghua Donglu, Haidian District, Beijing 100083, China. Electronic address:

Prebiotic effects of curdlan (1 → 3)-β-d-glucan oligosaccharides (GOS) were examined. GOS was tolerant against simulated gastrointestinal digestion, as well as low pH, thermal, and Maillard reaction conditions likely occurred during food processing. Growth of tested Lactobacillus (L.) strains was improved by GOS except L. brevis NRRL B-4527. E. coli did not grow on GOS as the only carbon source. In vitro batch fermentation using human faecal microbiota showed that GOS significantly increased the population of Lactobacillus sp. followed by Bifidobacterium sp. and Bacteroides sp. Growth of L. strains on GOS produced lactic acid, acetic, and propionic acid with decreased culture medium pH. Utilization pattern of GOS by representative L. strains was strain dependent. GOS with degree of polymerization (DP) of 2 and 3 were readily consumed. Findings here indicated that curdlan GOS (DP = 2 and 3) are promising physiologically active prebiotics for improvement of human intestinal health.
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http://dx.doi.org/10.1016/j.carbpol.2018.01.085DOI Listing
May 2018

Effect of slightly acidic electrolyzed water on bioactive compounds and morphology of broccoli sprouts.

Food Res Int 2018 03 4;105:102-109. Epub 2017 Nov 4.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, No 17, Qinghua East Road, Haidian District, Beijing, China; College of Food Science and Nutritional Engineering, China Agricultural University, No 17, Qinghua East Road, Haidian District, Beijing, China. Electronic address:

The producers of broccoli sprouts have become increasingly interested in improving their sulforaphane content. This study has evaluated the effects of slightly acidic electrolyzed water (SAEW) with different available chlorine concentrations (ACC) on broccoli sprouts: their content of some bioactive compounds such as glucosinolates, their morphology, and their total bacterial counts. The results have shown that SAEW might affect the content of sulforaphane by influencing the content of glucosinolates and the activity of myrosinase. SAEW inhibited the growth of broccoli sprouts: their fresh weight decreased as the available chlorine concentration (ACC) of the SAEW increased, but the different solutions did not affect their dry weight. The number of microorganisms on the broccoli sprout decreased by 1.71logCFU/g after using the SAEW with ACC value of 50mg/L treatment compared with tap water treatment. Overall, although SAEW adversely affected the morphology of broccoli sprouts, with a suitable ACC it can be a useful tool for enhancing the amount of secondary metabolites and reducing the microbial counts on broccoli sprouts intended for fresh consumption as a functional food.
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http://dx.doi.org/10.1016/j.foodres.2017.10.052DOI Listing
March 2018