绍兴市生食鱼中副溶血性弧菌毒力基因及耐药性与分子分型研究

目的 了解绍兴市生食鱼中副溶血性弧菌的污染状况、毒力基因携带情况、耐药性及分子分型情况。方法 采集绍兴地区354份生食鱼样品,参照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》进行菌株的分离与鉴定;利用荧光定量PCR技术对分离株进行毒力基因检测;采用微量肉汤稀释法和脉冲场凝胶电泳对分离株分别进行药物敏感试验和分子分型。结果 354份生食鱼中有13份样品检出副溶血性弧菌,总检出率为3.7%。13株菌全部检出tlh基因,tdh和trh基因均未检出。13株菌对头孢唑林均耐药,部分菌对氨苄西林耐药,对其他抗生素均敏感。PFGE条带分散,遗传特征多样。结论 绍兴市生食鱼中存在一定程度的副溶血性弧菌污染,菌株毒力基因携带率低,对头孢唑林普遍耐药,遗传特征多样。     

江苏省食源性副溶血性弧菌毒力基因和同源性分析研究

目的了解江苏省不同来源的副溶血性弧菌菌株的毒力基因携带情况以及分子遗传特征。方法对江苏省食源性疾病监测病人粪便、疾病暴发和食品监测分离到的副溶血性弧菌进行毒力基因和PFGE分子分型分析。结果暴发病人分离株92.3%携带毒力基因,监测病人分离株96.3%携带毒力基因。暴发食品分离菌株30%携带毒力基因,食品监测分离株不携带毒力基因。101株副溶血性弧菌经PFGE分子分型后,共形成43个带型模式(P1～P43),其中P9带型为最主要的带型模式;按相似度85%为判读标准可分为24个带型簇(cluster),G带型簇为最主要的带型簇(n=55)。结论病人分离株携带毒力基因的比例远高于食品分离株的比例,暴发病人分离株与疾病监测病人分离株携带毒力基因的比例无明显差异。PFGE结果显示我省副溶血性弧菌主要为G带型簇,以P9为主要带型模式,此带型模式为我省副溶血性弧菌的优势带型,在我省存在持续的传播。     

一起由副溶血性弧菌引起的聚集性腹泻事件的病原特征分析

目的 对2021年湖州市南浔区一起聚集性腹泻事件分离的副溶血性弧菌进行病原特征分析，为及时采取控制措施提供依据。方法 通过询问患者、医院核查等方法搜索到疑似病例59例，对采集的29份厨师、服务员和病例的肛拭子标本以及18份留存餐食进行病原学检测，采用血清学鉴定、脉冲场凝胶电泳（PFGE）、多重荧光聚合酶链式反应和微量肉汤稀释法分别对副溶血性弧菌分离株进行血清分型、分子分型、tlh/tdh/trh毒力基因检测和药敏试验。结果 从3份厨师和6例病例的肛拭子标本中分离到副溶血性弧菌，检出率为15.25%；分离株血清型均为O10:K4。所有菌株tlh、tdh基因均为阳性，trh基因均为阴性。9株分离株仅对氨苄西林耐药，对其他12种抗生素均敏感。经PFGE聚类分析，菌株间相似系数为100.0%，厨师分离株和病例分离株带型一致。结论 这是一起由O10:K4副溶血性弧菌引起的聚集性腹泻事件，分离株均携带tdh毒力基因，分离株之间的同源性高。     

基于环介导等温扩增法(LAMP)检测上海市售贝类产品中副溶血性弧菌的毒力菌株

基于环介导等温扩增法(LAMP)对上海市8-10月市售贝类产品中副溶血性弧菌毒力菌株(tdh和trh毒力基因)进行检测分析,共检测贝类样品180份,6个常规品种,实验同时采用PCR测定方法进行对比。结果表明,含tdh和trh毒力基因的副溶血性弧菌在市售贝类中的检出率分别是12.77%和11.66%,PCR的分析结果为11.11%和7.78%。对分离的毒力菌株进行血清型分型后发现了2株O3:K6型副溶血性弧菌,其中1株为毒力基因双阳性菌(tdh+/trh+)。2株O3:K6型副溶血性弧菌的PFGE条带型相似度较高(相似度90%)。这些结果表明上海市售贝类产品中副溶血性弧菌毒力菌株存在一定的污染,应引起足够重视。双阳性O3:K6型副溶血性弧菌的出现值得关注,应对各血清型菌株尤其是O3:K6型副溶血性弧菌的流行情况加强监测。PCR检测结果对比分析表明,LAMP方法适用于贝类产品中副溶血性弧菌毒力菌株的检测分析。     

2017—2021年泉州市食品污染风险监测中副溶血性弧菌耐药性及分子分型研究

目的 了解2017—2021年泉州地区食品污染风险监测中副溶血性弧菌的耐药情况以及菌株之间的同源性关系。方法 对各县区送检的食品样本进行副溶血性弧菌的增菌培养和分离鉴定，荧光定量PCR法进行毒力基因（tdh、trh和tlh）检测，微量肉汤稀释法进行药敏试验，脉冲场凝胶电泳（PFGE）技术进行分子分型，利用BioNumerics 6.6软件进行聚类分析。结果 210份食品样本共检出副溶血性弧菌65份，总检出率为30.95%；毒力基因检测中tlh基因100%检出，tdh和trh均未检出；药敏试验显示65株副溶血性弧菌对8种抗生素表现出不同程度的耐药，其中耐药最强的是多黏菌素E(27.70%,18/65)，而对美罗培南、环丙沙星、头孢他啶/阿维巴坦、替加环素、阿奇霉素、萘啶酸、链霉素、复方新诺明和阿米卡星9种抗生素不具有耐药性。65菌株通过PFGE图谱聚类分析显示63种型别，菌株之间相似度为34.67%～100.0%。结论 泉州地区食品中存在一定程度的副溶血性弧菌污染，所分离出的副溶血性弧菌对多种抗生素具有较高敏感性，菌株分布呈多态性，相互之间关系比较分散，亲缘关系较远。     

2019—2020年枣庄市副溶血性弧菌病人分离株的耐药性、毒力基因及分子分型分析

目的 了解枣庄市2019—2020年副溶血性弧菌(VP)病人分离株的耐药性、毒力基因携带情况和分子分型特征。方法 参照GB4789.7—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VP菌株的分离和鉴定,采用微量肉汤稀释法测定VP分离株对12种抗生素的耐药性,利用荧光定量聚合酶链式反应(PCR)技术检测VP分离株的毒力基因(tlh、tdh、trh),使用脉冲场凝胶电泳(PFGE)对分离株进行分子分型检测,并进行聚类分析。采用χ²检验对结果进行统计分析。结果 678份病人粪便标本中VP的检出率为4.57%,31株VP分离株对头孢唑啉耐药率为58.06%,多重耐药率为12.90%,其毒力基因tlh、tdh、trh的携带率分别为100%、96.78%、3.22%。31株VP分为17个带型,2个带型簇,优势带型簇涵盖了93.55%的菌株。结论 枣庄市VP病人分离株对头孢唑啉有较高耐药率,出现了多重耐药株。携带的主要毒力基因为tdh和tlh。PFGE带型集中、同源性高,提示应加强该地区VP的流行病学调查和溯源工作。     

中国部分水产品副溶血性弧菌毒力基因的分布特征

目的了解中国部分水产品中副溶血性弧菌毒力基因的分布情况。方法通过聚合酶链反应测定从中国部分水产品中分离的192株副溶血性弧菌是否携带毒力基因tdh、trh,及种特异性基因tlh、toxR。结果192株实验菌株tdh全阴性,4株trh阳性,毒力基因携带率2.08%;而tlh、toxR的携带率均为100%。结论中国副溶血性弧菌水产品分离株毒力基因携带率非常低。     

北京市市售带壳牡蛎致病性弧菌污染状况调查

目的了解北京市市售带壳牡蛎致病性弧菌污染状况。方法 2014年2~11月每月在某水产品批发市场的摊位抽样200只带壳牡蛎,共80份样品(其中腮和肠样品分别为40份)。用常规培养方法检测牡蛎腮和肠(含便)中致病性弧菌,对副溶血性弧菌进行血清学分型,荧光定量PCR检测副溶血性弧菌毒力基因tdh、trh和tlh。结果 80份牡蛎样品中,致病性弧菌阳性样品检出率为62.50%(50/80),副溶血性弧菌阳性菌株检出率为33.75%(27/80),溶藻弧菌阳性菌株检出率为31.25%(25/80);各牡蛎腮和肠样品中,致病性弧菌阳性检出率为67.50%(27/40)和57.50%(23/40);27株副溶血性弧菌共9种血清型;毒力基因检测结果表示,tlh均为阳性,tdh和trh均为阴性。结论北京市市售带壳牡蛎中致病性弧菌污染严重,以副溶血性弧菌和溶藻弧菌检出为主。     

一起多型别副溶血性弧菌引起农村喜宴食物中毒的溯源分析

目的通过对腹泻患者肛拭子标本和外环境样品的病原菌检测,利用脉冲场凝胶电泳(PFGE)分子分型技术对一起多型别副溶血性弧菌引起农村喜宴食物中毒原因开展溯源分析。方法对采集的共20份肛拭子标本和外环境样品进行病原学检测,并对检出的副溶血性弧菌进行血清分型、PFGE分型及tdh、trh、tlh、toxR基因检测。结果 20份样品/标本中15份检出副溶血性弧菌,11株为tdh+trh-tlh+toxR+基因型,4株为tdh-trh-tlh+toxR+基因型。其中12份患者肛拭子标本中有9份检出副溶血性弧菌,7份为O3∶K6血清型,2份为O2群;3份墩板涂抹样品中有2份检出O3∶K6血清型,1份为O1群;3份剩余食物样品中有2份检出副溶血性弧菌,分别为O1群和O10群;厨师肛拭子标本检出O11群副溶血性弧菌;PFGE聚类分析显示7份患者肛拭子标本和2份墩板涂抹样品中的O3∶K6型副溶血性弧菌带型高度同源,剩余食物来源的副溶血性弧菌核酸降解未能显示PFGE条带。结论本次事件是可疑食物交叉污染切菜墩板引起的以O3∶K6血清型为主的多种血清型别副溶血性弧菌的食物中毒。     

中国水产品中副溶血性弧菌耐药性及遗传特征分析

目的研究我国水产品中分离的副溶血性弧菌耐药性、产毒特性及遗传特征。方法对我国26个省、直辖市和自治区水产品中分离的1 137株副溶血性弧菌进行耐药性分析和毒力基因检测,并用脉冲场凝胶电泳方法比对产毒菌株的遗传特征。结果 1 137株副溶血性弧菌中有254株(22.3%)受试菌株对测定的12种抗生素全部敏感,883株(77.7%)对测定的抗生素呈现不同程度耐药。所有受试菌株对左氧氟沙星和庆大霉素抗生素敏感,主要耐受的抗生素为氨苄西林(53.7%,611/1 137)、阿莫西林/克拉维酸(46.3%,526/1 137)和头孢唑林(24.2%,275/1 137)。1 137株副溶血性弧菌分离株全部检出tlh基因,有3株检出tdh基因,有19株检出trh基因,其中2株同时检出tdh和trh基因。20株产毒菌株遗传特征分散,与其食品来源和耐药谱之间也无密切关联,其中4株对测定的抗生素均敏感,其余菌株主要对青霉素类和头孢类抗生素耐药。结论我国水产品中副溶血性弧菌对青霉素类抗生素普遍耐药,毒力基因携带率较低,产毒菌株遗传特征多样。     

Fertilization and early embryonic development in heifers and lactating cows in summer and lactating and dry cows in winter

Two experiments in two seasons evaluated fertilization rate and embryonic development in dairy cattle. Experiment 1 (summer) compared lactating Holstein cows (n = 27; 97.3 +/- 4.1 d postpartum [dppl; 40.0 +/- 1.5 kg milk/d) to nulliparous heifers (n = 28; 11 to 17 mo old). Experiment 2 (winter) compared lactating cows (n = 27; 46.4 +/- 1.6 dpp; 45.9 +/- 1.4 kg milk/d) to dry cows (n = 26). Inseminations based on estrus included combined semen from four high-fertility bulls. Embryos and oocytes recovered 5 d after ovulation were evaluated for fertilization, embryo quality (1 = excellent to 5 = degenerate), nuclei/embryo, and accessory sperm. In experiment 1, 21 embryos and 17 unfertilized oocytes (UFO) were recovered from lactating cows versus 32 embryos and no UFO from heifers (55% vs. 100% fertilization). Embryos from lactating cows had inferior quality scores (3.8 +/- 0.4 vs. 2.2 +/- 0.3), fewer nuclei/embryo (19.3 +/- 3.7 vs. 36.8 +/- 3.0) but more accessory sperm (37.3 +/- 5.8 vs. 22.4 +/- 5.5/embryo) than embryos from heifers. Sperm were attached to 80% of UFO (17.8 +/- 12.1 sperm/UFO). In experiment 2, lactating cows yielded 36 embryos and 5 UFO versus 34 embryos and 4 UFO from dry cows (87.8 vs. 89.5% fertilization). Embryo quality from lactating cows was inferior to dry cows (3.1 +/- 0.3 vs. 2.2 +/- 0.3), but embryos had similar numbers of nuclei (27.2 +/- 2.7 vs. 30.6 +/- 2.1) and accessory sperm (42.0 +/- 9.4 vs. 36.5 +/- 6.3). From 53% of the flushings from lactating cows and 28% from dry cows, only nonviable embryos were collected. Thus, embryos of lactating dairy cows were detectably inferior to embryos from nonlactating females as early as 5 d after ovulation, with a surprisingly high percentage of nonviable embryos. In addition, fertilization rate was reduced only in summer, apparently due to an effect of heat stress on the oocyte.     

Ovarian structures and circulating steroids in heifers and lactating cows in summer and lactating and dry cows in winter

Two experiments compared follicular and luteal development and circulating steroid concentrations from induced luteolysis to ovulation in lactating Holstein cows (n = 27; 40.0 +/- 1.5 kg milk/day) vs. nulliparous heifers (n = 28; 11 to 17 mo-old) during summer (Experiment 1), and in lactating (n = 27; 45.9 +/- 1.4 kg milk/d) vs. dry cows (n = 26) during winter (experiment 2). All females received PGF2,, 6 d after ovulation and were monitored until next ovulation by daily ultrasound and assay of serum progesterone (P4) and estradiol (E2). Every female was used two or three times. In Experiment 1, lactating cows had high incidence of multiple ovulation (63.5%) compared with heifers (1.3%). Among single ovulators, there was no difference in maximal size of ovulatory follicles between lactating cows and heifers (15.8 vs. 16.5 mm, respectively). However, lactating cows had lower peak serum E2 (8.6 vs. 12.1 pg/ml), took longer to ovulate after luteolysis (4.6 vs. 3.8 d), developed more luteal tissue volume (7,293.6 vs. 5,515.2 mm3), and had lower serum P4 on d 6 after ovulation (2.0 vs. 3.0 ng/ml) than heifers (data included multiple ovulators). In experiment 2, multiple ovulations were similar between lactating and dry cows (17.9 vs. 17.2%, respectively). Peak serum E2 was also similar between lactating and dry cows (7.6 vs. 8.5 pg/ml) although lactating cows had larger ovulatory follicles (18.6 vs. 16.2 +/- 0.4 mm). Lactating cows took longer to ovulate (4.8 vs. 4.2 d), developed more luteal tissue (7,599 vs. 5,139 +/- 468 mm3), but had similar serum P4 (2.2 vs. 1.9 ng/ ml) compared with dry cows. Therefore, lactating cows had similar or lower circulating steroid concentrations than dry cows or heifers, respectively, despite having larger ovarian structures.     

2018年深圳市售蔬菜和鸡蛋中氟虫腈及其代谢物的检测分析

目的 建立超高效液相色谱-串联质谱法同时测定蔬菜和鸡蛋中氟虫腈及其代谢物(氟甲腈、氟虫腈砜和氟虫腈亚砜), 并对深圳市售的蔬菜和鸡蛋中氟虫腈及其代谢物残留状况进行抽样检测。方法 采用QuEChERS前处理方法, 以C18色谱柱为分离柱, 以乙腈和10 mmol甲酸+6 mmol甲酸铵水溶液为流动相进行梯度洗脱, 用超高效液相色谱-串联质谱(ultra performance liquid chromatography-mass spectrometry/mass spectrometry, UPLC-MS/MS), 电喷雾电离(electrospray ionization, ESI), 多反应监测(multiple reaction monitoring, MRM)模式检测, 外标法同时定量测定氟虫腈及其代谢物。结果 方法的线性范围为0.1~2.0 μg/L, 线性相关系数均大于0.9994, 检出限0.0005 mg/kg, 定量限0.001 mg/kg; 蔬菜中3个水平的平均加标回收率88.0%~101.2%, 相对标准偏差(relative standard deviation, RSD)均小于8.5%; 鸡蛋中3个水平的平均加标回收率86.1%~104.8%, 相对标准偏差(RSD)均小于9.2%。结论 该方法具有操作简单、干扰少、快速、准确可靠等特点, 可适用于蔬菜鸡蛋中氟虫腈及其代谢物的检测。     

Zinc and iron contents and their bioaccessibility in cereals and pulses consumed in India

Several cereals and pulses commonly consumed in India were screened for zinc and iron contents and their bioaccessibility in the same was determined by equilibrium dialysis employing an in vitro simulated digestion procedure. Zinc content of cereals ranged from 1.08 mg/100 g in rice to 2.24 mg/100 g in sorghum. Zinc content of pulses was between 2.03 mg/100 g (whole chickpea) and 2.68 mg/ 100 g (decorticated chickpea). Iron content of cereals ranged from 1.32 mg% in rice to 6.51 mg% in sorghum, while that of pulses ranged from 3.85 mg% in decorticated green gram to 6.46 mg% in black gram. Dialyzability of zinc from pulses (27–56%) was generally higher than that from cereals (5.5–21.4%). Dialyzabilities of iron were almost similar from both cereals and pulses examined and were 4.13–8.05% in cereals and 1.77–10.2 % in pulses. A significant negative correlation between inherent phytate content and zinc dialyzability value was inferred in the case of pulses. Phytic acid content of the cereals had a significant negative influence on iron dialyzability. Inherent calcium had a negative influence on zinc dialyzability in cereals. Tannin did not have any significant influence on zinc or iron dialyzabilities from cereals and pulses. While both insoluble and soluble fractions of the dietary fibre generally interfered with zinc dialyzability, the insoluble fraction alone had this effect on iron dialyzability. The lower collective negative influence of the inherent factors on zinc dialyzability from pulses is consistent with their higher concentrations in these grains, relative to cereals. The negative correlation of inherent phytic acid with zinc and iron dialyzabilities was supported by enhanced dialyzabilities of these minerals upon partial removal of phytate from the grains by treatment with fungal phytase.     

果蔬及其制品中真菌毒素的污染与检测研究进展

果蔬在生长、贮存、运输及加工等一系列过程中,极易受到各种病原菌的侵染而发生腐烂,腐烂果蔬不仅造成巨大的经济损失,而且导致果蔬积累大量的真菌毒素。真菌毒素可通过食物链的传递对人或动物的健康带来巨大威胁。本文就果蔬中常见真菌毒素的种类、产毒菌株、侵染途径、产毒条件、毒性作用、检测方法和限量标准等方面进行详细的总结,旨在为果蔬中真菌毒素的控制提供参考。     

Fenvalerate residue level and dissipation in tea and in its infusion

Fenvalerate is a non-systemic insecticide/acaricide used in controlling a wide range of pests, including those resistant to organochlorine, organophosphorus and carbamate insecticides. The study investigated the dissipation behaviour (residue level) of fenvalerate in tea and its transfer during infusion. Fenvalerate was applied on tea crop at two dosages, 100 and 200 g a.i. ha^-1 (recommended and double the recommended) in the dry and wet seasons under field conditions. Samples (green tea shoots, made tea, its infusion and spent leaves) were analysed for fenvalerate by high-performance liquid chromatography using diode array detection. The residue dissipated faster in the wet season than in the dry season. Seven days after the treatment (normal round of plucking) the residues observed in the green shoots at the two dosages were 0.5 ± 0.01, 1.1 ± 0.01 and 0.4 ± 0.02, 0.9 ± 0.01 mg kg^-1 in the dry and wet seasons, respectively. During processing of green tea shoots to made tea a 30-40% loss of residue was observed. The transfer of residue from made tea to infusion was in the range 10-30% for both seasons, whereas 50-70% of the residues remained in the spent leaves. However, the degradation rate in both seasons followed first-order kinetics. The half-lives were in the range of 2-3 days for green shoots and made tea in both seasons.     

生物技术在制浆造纸中的应用与研究进展

介绍了生物技术在制浆造纸工业的应用与研究进展，包括生物制浆、生物漂白、生物脱墨及造纸过程中的生物技术等。     

蛋白质组学技术及其在乳及乳制品中的应用研究进展

蛋白质组学技术是近年来生命科学研究的重要工具,在食品、医学及动植物研究领域具有独特优势。利用蛋白质组学技术研究乳及乳制品,深入阐明其中蛋白质的表达及动态变化已成为当前的研究热点。该文主要综述了蛋白质组学的概念、常用技术及应用领域,重点介绍蛋白质组学在乳及乳制品领域,特别是在乳脂肪球膜蛋白、乳清蛋白、乳及乳制品加工过程以及干酪制品中的研究应用,探讨了目前乳及乳制品蛋白质组学研究中存在的问题与局限,并对蛋白质组学及其在乳及乳制品中的应用前景进行了总结与展望,为应用蛋白质组学技术深入研究乳及乳制品提供了理论依据。     

冰酒中的毕赤属和汉逊属酵母菌的筛选及其在葡萄酒酿造中的应用

从冰葡萄酒自然发酵过程中分离、鉴定出10株毕赤属(Pichia)和汉逊属(Hanseniaspora)酵母,对其耐受性(酒精、糖、酸、SO2)进行研究,筛选得到4株耐受性能优良的酵母菌株,编号为"HO"和"HU"(Hanseniaspora属)、"PO"和"PK"(Pichia属)。再将此4个酵母菌株与商业酿酒酵母(Saccharomyces cerevisiae)按不同比例(1:1和10:1,1:1编号为1,10:1编号为2),先接种非酿酒酵母菌株,48 h后再接种酿酒酵母的顺序进行混合发酵。研究了发酵过程中菌群及乙醇的动态变化,又对发酵结束后冰葡萄酒的主要成分进行分析。结果显示:"HO"随接种量的增加菌落数受到抑制,"HU""PO"及"PK"随接种量的增大菌落数受到促进作用;HO1、HU1、HU2、PK1、PK2乙醇含量在发酵前期增长较少,在发酵中期迅速增大,HO2、PO1、PO2乙醇含量在发酵前期增长较多,在发酵中期显著增大,所有发酵乙醇含量皆于第21天稳定在9%左右;"HO""HU""PO"及"PK"不同比例混合发酵各理化指标(酒精度、总糖、总酸、有机酸)均符合国家葡萄酒标准,"HU"乙酸含量过高,葡萄酒品质中含有缺陷。以上结果表明4株酵母菌株均可应用于本土葡萄酒的酿造中,为生产具有本地特色的葡萄酒提供一定的参考。     

Fenvalerate residue level and dissipation in tea and in its infusion

Fenvalerate is a non-systemic insecticide/acaricide used in controlling a wide range of pests, including those resistant to organochlorine, organophosphorus and carbamate insecticides. The study investigated the dissipation behaviour (residue level) of fenvalerate in tea and its transfer during infusion. Fenvalerate was applied on tea crop at two dosages, 100 and 200?g a.i.?ha^?1 (recommended and double the recommended) in the dry and wet seasons under field conditions. Samples (green tea shoots, made tea, its infusion and spent leaves) were analysed for fenvalerate by high-performance liquid chromatography using diode array detection. The residue dissipated faster in the wet season than in the dry season. Seven days after the treatment (normal round of plucking) the residues observed in the green shoots at the two dosages were 0.5?±?0.01, 1.1?±?0.01 and 0.4?±?0.02, 0.9?±?0.01?mg?kg^?1 in the dry and wet seasons, respectively. During processing of green tea shoots to made tea a 30–40% loss of residue was observed. The transfer of residue from made tea to infusion was in the range 10–30% for both seasons, whereas 50–70% of the residues remained in the spent leaves. However, the degradation rate in both seasons followed first-order kinetics. The half-lives were in the range of 2–3 days for green shoots and made tea in both seasons.