Leuconostoc mesenteroides are characterized by α-glucan production in the presence of sucrose. Although they lack the enzymes to scavenge reactive oxygen species (ROS), strains of L. mesenteroides are generally tolerant to oxygen. Despite the wide applications of L. mesenteroides and α-glucans in food and medical industry, mechanisms underlie α-glucan synthesis, and their roles in oxygen-tolerance remain to be elucidated. This study aimed at functional characterization of the enzyme for α-glucan synthesis in L. mesenteroides CGMCC10064 and addressing its role in oxygen stress. 1323 was identified as a secreted glucansucrase via SDS-PAGE followed by MALDI-TOF MS and Western blot. Its enzyme activity was characterized via in situ polymer synthesis and function blockade by a specific antibody. Finally, 1323-encoding gene was cloned and expressed in E. coli. α-glucan was synthesized in vitro with recombinant 1323 and its potential in oxygen stress relief was investigated. The α-glucan obtained improved the aerobic growth of L. mesenteroides strains via reduction of the oxidation–reduction potential as well as ROS accumulation. Moreover, oxygen stress relief by the α-glucan improved the growth and survival of probiotic Lactobacillus and Bifidobacterium strains under oxygen stress. These results highlighted the potential of a novel secreted glucansucrase and its α-glucan product in oxygen stress relief and cultivation and preservation of oxygen-sensitive bacteria.

Freezing stress can seriously affect plant growth and development, but the mechanisms of these effects and plant responses to freezing stress require further exploration. Here, we identified a NAM, ATAF1/2, and CUC2 (NAC)-family transcription factor (TF), NAC056, that can promote freezing tolerance in Arabidopsis. NAC056 mRNA levels are strongly induced by freezing stress in roots, and the nac056 mutant exhibits compromised freezing tolerance. NAC056 acts positively in response to freezing by directly promoting key C-repeat-binding factor (CBF) pathway genes. Interestingly, we found that CBF1 regulates nitrate assimilation by regulating the nitrate reductase gene NIA1 in plants; therefore, NAC056-CBF1-NIA1 form a regulatory module for the assimilation of nitrate and the growth of roots under freezing stress. In addition, 35S::NAC056 transgenic plants show enhanced freezing tolerance, which is partially reversed in the cbfs triple mutant. Thus, NAC056 confers freezing tolerance through the CBF pathway, mediating plant responses to balance growth and freezing stress tolerance.

加强创新创业教育,培养拔尖创新人才,是高校落实创新驱动发展战略的重要举措,对经济社会发展起到关键推动作用.该文通过新产品开发与创业导论课程的线上线下一体化教学改革,形成理论教学、实践教学、科技创新、创业辅导四层次结合的课程体系,实现知识拓展和混合式教学质量提升,以学生为中心促进知识内化,全面促进大学生创新创业素养及能力的培养.

Gut dysbiosis causes damage to the intestinal barrier and is associated with type 2 diabetes mellitus (T2DM). We tested the potential protective effects of probiotic BL21 and LRa05 on gut microbiota in type 2 diabetes mellitus mice and determined whether these effects were related to the modulation of gut microbiota.Thirty specific pathogen-free C57BL/6J mice were randomly allocated to three groups—the (CTL) control group, HFD/STZ model (T2DM) group, and HFD/STZ-probiotic intervention (PRO) group—and intragastrically administered strains BL21 and LRa05 for 11 weeks. The administration of strains BL21 and LRa05 significantly regulated blood glucose levels, accompanied by ameliorated oxidative stress in mice. The BL21/LRa05-treated mice were protected from liver, cecal, and colon damage. Microbiota analysis showed that the cecal and fecal microbiota of the mice presented significantly different spatial distributions from one another. Principal coordinate analysis results indicated that both T2DM and the BL21/LRa05 intervention had significant effects on the cecal contents and fecal microbiota structure. In terms of the fecal microbiota, an abundance of Akkermansia and Anaeroplasma was noted in the PRO group. In terms of the cecal content microbiota, enrichment of Akkermansia , Desulfovibrio , Bifidobacterium , Lactobacillus , and Limosilactobacillus was noted in the PRO group. The probiotics BL21 and LRa05 prevent or ameliorate T2DM by regulating the intestinal flora and reducing inflammation and oxidative stress. Our results suggest that BL21 and LRa05 colonize in the cecum. Thus, BL21/LRa05 combined with probiotics having a strong ability to colonize in the colon may achieve better therapeutic effects in T2DM. Our study illustrated the feasibility and benefits of the combined use of probiotics and implied the importance of intervening at multiple intestinal sites in T2DM mice.

食品安全与卫生学是上海商学院食品质量与安全专业核心课程,也是上海市一流本科专业课程.文章基于IFT(Institute of Food Technologists)专业认证教育理念,融合课程思政,围绕综合性人才培养目标,通过线上线下融合、翻转课堂、案例教学、科研项目引领等形式开展教学,建立了基于学生学习效果的课程评价导向和课程目标达成度分析报告,增强学生食品科学传播能力、实践动手能力和解决问题能力,形成了团队协作、共同学习进步的良好氛围.

A novel exopolysaccharide named BD0.4 was purified from the fermentation broth of Paenibacillus bovis sp. nov BD3526 in wheat bran medium via anion exchange column chromatography. Its fine structure was identified by a variety of physical and chemical methods. BD0.4, with the weight average molecular weight of 376 kDa, consisted of glucuronic acid, glucose and fucose in a molar ratio of 1.58:1:1.66. The backbone included 1,3-linked Fuc, 1,3,4-linked Fuc, 1,3-linked Glc and 1,4-linked GlcA residues, with the branching point located at the O4 position of 1,3,4-linked Fuc residues, and the branched chain composed of terminal GlcA residues. BD0.4 could improve the phagocytic ability of macrophages and significantly stimulate the secretion of NO, TNF-α, IL-1β and IL-6 from RAW264.7 cells in a dose-dependent manner. BD0.4 could promote the expression of NF-кB and cause nuclear translocation of NF-κB p65, indicating that BD0.4 probably exerted immune activity through the NF-κB signaling pathway.

以植物乳杆菌GH-6发酵黑果枸杞浆为研究对象,分析发酵前后黑果枸杞浆中差异性代谢物的含量变化.采用超高效液相色谱-静电场轨道肼质谱联用(UPLC-Orbitrap MS)技术,首先对发酵前后黑果枸杞浆的成分进行分析,共鉴定出61个代谢物.随后,在原浆、发酵液以及添加蔗糖及乳清蛋白后的发酵液中筛选出22个差异性代谢物,其中4种花青素类、3种有机酸类、2种糖类、3种氨基酸类、7种小肽类和3种嘌呤类.结果表明,由于植物乳杆菌GH-6糖苷酶的水解作用,促使花青素类及糖类物质的含量上升;经发酵引起的乳酸生成增加,可有效调节黑果枸杞发酵液的风味;益生乳酸菌具有的肽转运系统使得二肽、三肽类物质水解,天冬氨酸-异亮氨酸、缬氨酰-谷氨酸及缬氨酰-缬氨酰-缬氨酸在发酵后未被检出,说明这三种肽类可能优先被植物乳杆菌GH-6所利用.此外,植物乳杆菌GH-6还具有降解嘌呤的能力,致使发酵液中嘌呤类物质的含量降低.总之,通过植物乳杆菌GH-6发酵能显著影响黑果枸杞浆中的代谢变化,研究将为黑果枸杞有效营养成分的开发利用以及发酵制品等相关产品的研发提供参考和新的应用方向.

Background Levan is a well-known homopolymer of fructose composed predominantly of β-(2, 6) fructofuranosyl linkages in the backbone with occasional β-(2, 1) linkages in the branch chains with varied applications. However, high production cost due to low yield of microbial levan has become a bottleneck for its practical applications. Furthermore, factors affecting the molecular mass of the synthesized levan by Leuconostoc spp. during prolonged cultivation is not fully elucidated. Methods The cultivation condition for Leuconostoc citreum BD1707 to synthesize levan was optimized by single-factor experiments and subsequently with response surface methodology (RSM). The average molecular weight (Mw) of levan synthesized by the strain L.citreum BD1707 under the optimized cultivation conditions was monitored by high-performance size exclusion chromatography (HPSEC). Finally, the enzyme with levan-degrading activity was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Results The levan yield of BD1707 reached 34.86 g/L with a corresponding productivity of 7.47 g/L/d under the optimal cultivation conditions deduced by RSM, i.e., cultivation at 26 °C and 200 rpm for 112 h in tomato juice supplemented with 172 g/L sucrose with an initial pH value of 6.12. The Mw of levan reached a peak value of 2.320 × 10 7 Da at 6 h of cultivation under the optimized cultivation conditions and then gradually decreased to 8.809 × 10 6 Da after 120 h of cultivation. Conclusion The levan yield of the strain L.citreum BD1707 could be sufficiently enhanced via cultivation condition optimization. The decrease in molecular mass of the synthesized levan was attributed predominantly to the hydrolytic activity of levansucrase secreted by L.citreum BD1707 during cultivation, with an estimated Mw of 130 KD by SDS-PAGE, while the effect of acid hydrolysis could be nearly neglected.

“食品微生物检验学”作为食品质量与安全相关专业的核心课程,具有很强的实践性和应用性.结合ADDIE模型,对课程进行分析、设计、开发、实施和评价5步改革,有利于创建先进的教学模式,切实提高教学质量和学生的实践能力,为培养应用型人才奠定基础.

研究牛类芽孢杆菌(Paenibacillus bovis)BD3526抑制变形链球菌(Streptococcus mutans)ATCC35668的特性,拓宽P.bovis BD3526代谢产物的抑菌用途.主要研究P.bovis BD3526在麦麸培养基中的发酵特性和发酵上清液对蛋白水解酶和过氧化氢酶的敏感性、不同pH耐受性和热稳定性,以及对口腔中常见乳杆菌属生长的影响.结果表明,P.bovis BD3526发酵12 h后进入稳定期,在36 h时活性达到4.58×108 CFU/mL、pH值5.20,对Streptococcus mutans ATCC35668抑菌圈直径为(21.27±0.71)mm.该发酵上清液对口腔中常见的有益菌(植物乳杆菌和干酪乳杆菌)无抑菌活性,但对链球菌属微生物抑制作用明显.目标抑菌物质具有良好的热稳定性和pH稳定性、对消化系统蛋白水解酶和过氧化氢酶不敏感;经链霉蛋白酶处理后抑菌活性消失,表明该抑菌物质的化学结构中含有肽类成分.P.bovis BD3526代谢麦麸合成的抑菌物质对S.mutans ATCC35668具有强烈抑制且稳定的抑制效果,这为将来开发特异性功能食品配料或口腔护理产品奠定了理论基础.

线上教学被赋予了重要的历史使命,发挥了重要的作用,但是师生不能面对面直接交流导致情感交互不够,企业现场实践缺失.因此,为确保疫情防控时期"食品质量管理"课程的教学质量和效果,通过开设"新冠疫情和食品质量安全""食品人战疫故事""食品工厂云参观"及"家庭厨房烹饪危害分析与质量控制"等板块,探索了线上教学与课程思政资源的融合并进行了实践,以期为食品专业其他课程的课程思政改革提供参考.

Biodegradable membranes of chitosan and its composite with other natural polymers provide a promising solution for biomaterials. To further improve the antibacterial activities of chitosan (CS)/hydroxypropyl methyl cellulose (HPMC) membrane, natural extracts tea polyphenols (TP) were employed in this work. And TP was encapsulated by beta-cyclodextrin (CD) beforehand to improve its compatibility with HPMC. To our knowledge, it's the first time ever reported to use CD encapsulated TP in CS/HPMC membranes. And variety characterization results such as Fourier transform infrared spectroscopy (FTIR), ultraviolet spectra (UV) and dynamic light scattering (DLS) showed that TP had successfully encapsulated with CD. After the solvent blending of CS/HPMC and CDTP, CS/HPMC/CDTP membrane was prepared by a casting method and exhibited good toughness and tensile strength. Finally, bacterial inhibitive rate and inhibition zones of the membrane with E. coli and S. aureus proved the enhanced antibacterial as expected. And the morphology of the bacteria was observed to estimate the possible interaction approach of materials and bacteria. The novel biodegradable membrane can be used for antibacterial coating application.

在"食品营养学"课程实践教学环节中,以食品营养强化章节内容为基础,结合我国《预包装食品营养标签通则》设计综合实验项目"营养强化及营养标签制作".实验内容包含:①营养强化食品的设计与制作;②营养成分分析;③营养标签制作3个部分.每个实验小组人数5人,实验时间12学时,在2～3个教学日完成.通过在15名学生中进行的尝试性实验对其实施效果、注意要点进行深入探讨.

Chronic low-grade inflammation is widely involved in the development and progression of metabolic syndrome, which can lead to type 2 diabetes mellitus (T2DM). Dysregulation of proinflammatory and anti-inflammatory cytokines not only impairs insulin secretion by pancreatic β-cells but also results in systemic complications in late diabetes. In our previous work, metabolites produced by Paenibacillus bovis sp. nov. BD3526, which were isolated from Tibetan yak milk, demonstrated antidiabetic effects in Goto–Kakizaki (GK) rats. In this work, we used single-cell RNA sequencing (scRNA-seq) to further explore the impact of BD3526 metabolites on the intestinal cell composition of GK rats. Oral administration of the metabolites significantly reduced the number of adipocytes in the colon tissue of GK rats. In addition, cluster analysis of immune cells confirmed that the metabolites reduced the expression of interleukin (IL)-1β in macrophages in the colon and increased the numbers of dendritic cells (DCs) and regulatory T (Treg) cells. Further mechanistic studies of DCs confirmed that activation of the WNT/β-catenin pathway in DCs promoted the expression of IL-10 and transforming growth factor (TGF)-β, thereby increasing the number of Treg cells.

Chitosan and its derivatives are widely used in medical, cosmetic and food fields. In this study, chitosan-N-arginine (CSA) was synthesized and characterized by Fourier-transform infrared (FT-IR), 1H NMR, gel permeation chromatography (GPC), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). A novel antibacterial composite film consisting of CSA, hydroxypropyl methylcellose (HPMC) and glycerol was then prepared. The transparent and homogeneous film presented good compatibility between CSA and HPMC, confirmed by SEM. The thickness of the film was about 44.8 μm and its moisture content was 23.0%. Antimicrobial evaluation of CSA/HPMC film showed 9.0 mm bacteriostatic diameter zone against E. coli and 10.5 mm one against S. aureus. The film exhibited cell biocompatibility and promoted proliferation with L929 cell cytotoxicity test. Both antibacterial and cytotoxic results showed that the CSA/HPMC film was a promising material for medication, cosmetics and food preservation applications.

In this present study, the structure and immunomodulatory activity of a novel polysaccharide (WSRP-1b) from Kushui rose (Rosa setate x Rosa rugosa) waste were investigated. Structure characterization demonstrated that WSRP-1b had a weight-average molecular weight of 1.11 x 10(4) Da and consisted of glucose (42.6 %), mannose (21.4 %), arabinose (9.9 %), xylose (2.2 %), and galactose (23.9 %). Its backbone was composed of 1, 4-linked alpha-Glcp, 1, 4-linked beta-Glcp, and 1, 4-linked beta-Manp, with branches of 1, 4-linked alpha-Glcp and 1, 4-linked beta-Manp substituted at C-6 by 1, 6-linked beta-Galp. The branches mainly contained 1, 5-linked Araf, terminal arabinose and terminal glucose. Bioactivity assays showed that WSRP-1b had immunomodulatory activity by enhancing phagocytosis of macrophages, increasing production of ROS, NO, cytokines (IL-6, TNF-alpha), and activating NF-kappa B signaling pathway. These results suggested that it could be developed as a potential and safe immunomodulatory agent in fields of pharmacological or functional foods.

自制酸奶,又称"DIY"酸奶,指消费者利用酸奶发酵剂和牛奶自己制作而成的发酵乳制品.从多角度对自制酸奶和商业化酸奶进行综合评价,结果发现:商业化酸奶在发酵、冷藏及稳定性方面优势明显,而自制酸奶则具有操作自由度高的特点.

为制备高活性冻干粉,通过响应面法对BD1710菌株的培养条件进行优化,结果显示:当培养时间为29.5 h,培养温度为29.5℃,初始pH值为7.3,蔗糖浓度为16.8％时,菌株BD1710冻干存活率可达92.44％,与理论值基本一致,并显著优于传统工艺的冻干保护效果(76.81％).推测可能是BD1710合成的胞外多糖以及培养基中的天然冻干保护剂为冻干过程中的微生物细胞提供了主要的细胞保护.因此,发酵后直接冻干可作为制备高活性肠膜明串珠菌制剂的一种简易手段.

Gut microbiota is closely related to type 2 diabetes mellitus (T2DM). The gut microbiota of patients with T2DM is significantly different from that of healthy subjects in terms of bacterial composition and diversity. Here, we used the fermentation products of Paenibacillus bovis sp. nov. BD3526 to study the disease progression of T2DM in Goto-kakisaki (GK) rats. We found that the symptoms in GK rats fed the fermentation products of BD3526 were significantly improved. The 16S rRNA sequencing showed that the fermentation products of BD3526 had strong effects on the gut microbiota by increasing the content of Akkermansia. In addition, the interaction of the genus in the gut of the BD3526 group also significantly changed. Additional cytokine detection revealed that the fermentation products of BD3526 can reduce the inflammatory factors in the intestinal mucus of GK rats and thereby inhibit the inflammatory response and ameliorate the symptoms of T2DM.

多黏类芽孢杆菌(Paenibacillus polymyxa)BD3736具有代谢脱脂乳、合成α-葡萄糖苷酶抑制剂(α-glucosidase inhibitors,AGIs)的能力.通过单因素试验,初步分析接种量、发酵温度、脱脂乳质量浓度及培养时间对AGIs的α-葡萄糖苷酶抑制活性的影响,并确定主要的影响因素;继而采用3因素3水平的响应面分析法,对多黏类芽孢杆菌BD3736在发酵脱脂乳中合成AGIs的发酵条件进行优化,获得的最优发酵条件为发酵温度31.5℃、接种量3.5％、培养时间4 d.在此条件下,发酵液上清对α-葡萄糖苷酶的半数最大抑制质量浓度为30.5 mg/mL.