Phenolic profiling reveals the metabolite basis of flesh colour and fresh-cut browning in apple fruit

Flesh colour, which is affected by cultivars and browning, can largely impact consumer acceptance in fresh-cut apples. The study profiled phenolic metabolites from apple flesh of twenty-three cultivars by widely targeted metabolomics. Comparison among white- and yellow-fleshed cultivars showed fifteen phenolics, mainly quercetin 3-O-glucoside, hyperoside, hesperetin 5-O-glucoside and cymaroside, in white-fleshed apples were significantly higher than those in yellow-fleshed apples. It may indicate a metabolite basis of yellow and white flesh colour, and better potential nutrition in white-fleshed apples. In addition, ten phenolic metabolites including five cyanidin glycosides showed significant differences between the highest and the lowest browning groups, indicating them may be crucial in browning of fresh-cut apple. This work elucidates the differences of phenolic profiles among apple cultivars with different flesh colour and provides useful data to evaluate the suitability of apple for fresh-cut processing.     

汉江上游干支流沉积物细菌群落多样性和影响因素

为了解汉江上游干支流沉积物细菌多样性以及确定性过程和随机性过程在沉积物细菌群落构建过程中的相对重要性,基于Illumina高通量测序技术,分析了环境因子对细菌群落组成的影响,采用非度量多维尺度(NMDS)排序探究了季节之间沉积物细菌群落的差异,并结合中性群落模型和标准化随机率量化了确定性过程和随机过程对群落构建的影响。结果表明:汉江上游及其支流细菌群落主要由变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)、蓝藻门(Cyanophyta)、浮霉菌门(Planctomycetes)和酸杆菌门(Acidobacteria)等组成；细菌群落在不同季节有显著差异；地理距离和环境因子对细菌群落结构影响较小,确定性过程并未在细菌群落组成中起到主导作用；随机过程很大程度上影响了群落在秋季和春季的组成,是沉积物细菌群落构建的主导因素。     

Observation of table-like magnetocaloric effect and large refrigerant capacity in Nd6Fe13Pd1–xCux compounds

The table-like magnetocaloric effect is significant for the magnetic refrigeration applications above 20 K based on the Ericsson cycle. Herein, we prepared a series of Nd₆Fe₁₃Pd_1–xCu_x (x = 0.05, 0.1, 0.15) compounds by the arc-melting method. These compounds show the single crystalline phase in the tetragonal Nd₆Fe₁₃Si-type structure with the space group I4/mcm. A magnetic phase transition from ferromagnetism to antiferromagnetism and a metamagnetic transition from the antiferromagnetic state to the ferromagnetic state are observed in each of the compounds. The compounds exhibit table-like magnetocaloric effects with large refrigerant capacities. A constant ΔS_M in a temperature span of 40 K in the Nd₆Fe₁₃Pd_0.85Cu_0.15 compound are observed. For a field change of 0–5 T, the peak values of –ΔS_M for the Nd₆Fe₁₃Pd_0.95Cu_0.05, Nd₆Fe₁₃Pd_0.90Cu_0.10, and Nd₆Fe₁₃Pd_0.85Cu_0.15 compounds are estimated to be 4.8, 4.6 and 4.4 J/(kg·K) with corresponding refrigerant capacity values of 323, 331 and 316 J/kg, respectively. The obtained table-like magnetocaloric effects with large refrigerant capacities as well as fairly small thermal and magnetic hysteresis deem these series of compounds good candidates for single-phase magnetic refrigeration based on the Ericsson cycle.     

菌酶协同改善花生粕的饲用品质

花生粕是重要的蛋白饲料原料，但由于其氨基酸不平衡，特别是精氨酸与赖氨酸比例严重失衡（精氨酸与赖氨酸含量比值在3~4，理想的精氨酸与赖氨酸含量比值为1.0），限制了其在动物养殖中的应用。研究了复合酶预处理结合乳酸菌发酵花生粕对其品质的改善。结果表明：经菌酶协同处理后，花生粕粗蛋白质含量由46.4%提高至506%，大分子蛋白明显降解为小分子蛋白，酸溶蛋白质含量由2.3%提高至17.8%，多肽含量由1.6%提高至15.7%，蛋氨酸和赖氨酸含量分别提高了77.1%和42.0%，精氨酸降解率为18.7%，精氨酸与赖氨酸含量比值从3.7降低至2.1，总酸含量由06%提高到4.7%，其中乳酸含量由0.64 mg/g提高至14.63 mg/g。菌酶协同处理后的花生粕抗氧化性明显增强，其中每克菌酶协同处理后的花生粕对羟自由基的清除能力与171.6 mg VC相当，比花生粕（与47.6 mg VC相当）提高了2.6倍。     

Hsp100 Molecular Chaperone ClpB and Its Role in Virulence of Bacterial Pathogens

This review focuses on the molecular chaperone ClpB that belongs to the Hsp100/Clp subfamily of the AAA+ ATPases and its biological function in selected bacterial pathogens, causing a variety of human infectious diseases, including zoonoses. It has been established that ClpB disaggregates and reactivates aggregated cellular proteins. It has been postulated that ClpB’s protein disaggregation activity supports the survival of pathogenic bacteria under host-induced stresses (e.g., high temperature and oxidative stress), which allows them to rapidly adapt to the human host and establish infection. Interestingly, ClpB may also perform other functions in pathogenic bacteria, which are required for their virulence. Since ClpB is not found in human cells, this chaperone emerges as an attractive target for novel antimicrobial therapies in combating bacterial infections.     

红色烟火着色剂MOF[Sr2(DTDA)(H2O)6]n的制备与性能

以富氮羧酸类分子2,2'-(3,3'-偶氮-双(1H-1,2,4-三唑-5基))二乙酸(H2DTDA)与氢氧化锶八水合物为原料,在水热条件下制备了一种金属有机框架(MOF)结构的新型红色烟火着色剂[Sr_2(DTDA)(H_2O)_6]_n(1);采用傅里叶变换红外光谱(FT-IR)、X射线单晶衍射(XRD)、粉末X射线单晶衍射(PXRD)和元素分析等对化合物结构进行了表征;采用热重法(TG)-差示扫描量热法(DSC)、BAM标准法测试了化合物1的热性能和感度性能;设计了烟火剂配方,对化合物1应用于红色烟火着色剂的可行性进行分析。结果表明,化合物1是一种具有二维空间结构的MOF材料,其层状结构之间存在丰富的氢键作用;放大合成的水热实验同样可以得到高纯度的化合物1;撞击感度为80 J,摩擦感度 360 N;化合物1可作为红色着色剂应用于烟火剂配方中。     

Macrofungi: A review of cultivation strategies,bioactivity, and application of mushrooms

The production of macrofungi (mushrooms) as well as their economic value have been steadily increasing globally. The use of functional foods, dietary supplements, and traditional medicines derived from macrofungi is increasing as they have numerous health benefits as well as abundant nutrients. Macrofungi are diverse with complex and highly varied growth conditions and bioactive constituents, most macrofungal resources have not yet been fully explored and applicated, leading to an urgent need for appropriate strategies to address the problem. Increasing attention has been paid to the macrofungal cultivation and application, in particular, potential prebiotics. Herein, the present review comprehensively summarizes recent progress in the cultivation, newly identified bioactive constituents, and their effects on gut microbiota as well as the potential ways in which they affect human health. Moreover, the macrofungal food development is discussed to improve food nutritional value and change the quality characteristics of food. Finally, the review addresses consumer safety concerns and the prospective genetic manipulation of macrofungi. We hope that this review can provide a comprehensive research reference for ensuring the safety and efficacy, along with maximizing the value and profitability of macrofungi production.     

2016年上海市市售肉制品中沙门菌耐药谱与分型研究

目的 研究上海市市售肉制品中沙门菌血清型、耐药谱和分子分型特征。方法 2016年1～8月在上海市所辖16个行政区,随机选择1个密集型社区,抽取1家超市或市场作为哨点,定期采集畜、禽类肉制品,按国家食品安全风险评估中心(CFSA)食源性疾病监测方案进行沙门菌分离、血清分型、抗生素定量检测与剂量评估、优势菌的分子分型。结果 606份样品包括猪、鸡、鸭、牛、羊、鹅肉制品,共分离沙门菌158株,总阳性率为26.1%,畜肉和禽肉来源分别占52.5%(83/158)和47.5%(75/158)。前5位沙门菌血清型依次为肠炎沙门菌、鼠伤寒沙门菌、德尔卑沙门菌、罗森沙门菌和印第安纳沙门菌,畜肉和禽肉来源优势菌型间差异有统计学意义(P<0.05)；菌株对磺胺异噁唑耐药率最高(79.7%,126/158),对链霉素、萘啶酸、氨苄西林、四环素和氯霉素耐药率在38.0%～77.8%,多重耐药(MDR)菌株(≥3类)占77.8%(123/158),猪肉来源沙门菌对庆大霉素、链霉素、磺胺异噁唑、复方新诺明、氯霉素、四环素耐药率均高于鸡肉来源沙门菌,鸡肉来源沙门菌对头孢噻呋、头孢曲松、萘啶酸耐药率均高于猪肉来源沙门菌,差异均有统计学意义(P<0.05),32.9%(52/158)的菌株对至少6种抗生素超检测限值；肠炎沙门菌有15个分型,以1型和3型为优势型；鼠伤寒沙门菌有23个分型,具有遗传多样性特征。结论 上海市市售肉制品沙门菌暴露以猪肉和鸡肉来源为主,肉制品中多重耐药沙门菌污染严重。猪肉来源的罗森沙门菌和鸡肉来源的吉韦沙门菌是新输入性的血清型。     

大连市不同海产品中副溶血性弧菌污染的健康风险分级研究

目的对大连市不同海产品中副溶血性弧菌(Vibrio parahaemolyticus, VP)污染的健康风险进行分级和评价。方法 2017年1～10月,在大连市10个县市区分层随机采集4类944份常见海产品。依据GB 4789.7—2013《食品安全国家标准食品微生物学检验副溶血性弧菌检验》进行海产品中VP定量检测,使用实时荧光定量聚合酶链式反应(PCR)方法进行VP毒力基因检测;采用食物频率法获得各类海产品的消费量数据;利用专家咨询法获得海产品交叉污染和烹调习惯参数;采用快速微生物定量风险评估(sQMRA)方法,对4类海产品中致病性VP的健康风险进行分级。结果甲壳类导致人体感染致病性VP发病风险和年发病例数最高,分别为3.5×10~(-6)和2 799.3例。鱼类导致人体感染致病性VP发病风险和年发病例数居第二位,分别为1.1×10~(-6)和1 304.4例。海产品导致人群VP发病的主要途径为交叉污染。结论应关注大连市甲壳类中VP对人群的致病风险,重点控制海产品在加工处理过程中VP的交叉污染。