Characterization and Structure Analysis of a Novel Bacteriocin,Lacticin Z,Produced by Lactococcus lactis QU 14

A novel bacteriocin, lacticin Z, produced by Lactococcus lactis QU 14 isolated from a horse’s intestinal tract was identified. Lacticin Z was purified through a three step procedure comprised of hydrophobic-interaction, cation-exchange chromatography, and reverse-phase HPLC. ESI-TOF MS determined the molecular mass of lacticin Z to be 5,968.9 Da. The primary structure of lacticin Z was found to consist of 53 amino acid residues without any leader sequence or signal peptide. Lacticin Z showed homology to lacticin Q from L. lactis QU 5, aureocin A53 from Staphylococcus aureus A53, and mutacin BHT-B from Streptococcus rattus strain BHT. It exhibited a nanomolar range of MICs against various Gram-positive bacteria, and the activity was completely stable up to 100 °C. Unlike many of other LAB bacteriocins, the stability of lacticin Z was emphasized under alkaline conditions rather than acidic conditions. All the results indicated that lacticin Z belongs to a novel type of bacteriocin.     

PELPIII: the class III pistil‐specific extensin‐like Nicotiana tabacum proteins are essential for interspecific incompatibility

Pre‐zygotic interspecific incompatibility (II) involves an active inhibition mechanism between the pollen of one species and the pistil of another. As a barrier to fertilization, II effectively prevents hybridization and maintains species identity. Transgenic ablation of the mature transmitting tract (TT) in Nicotiana tabacum resulted in the loss of inhibition of pollen tube growth in Nicotiana obtusifolia (synonym Nicotiana trigonophylla) and Nicotiana repanda. The role of the TT in the II interaction between N. tabacum and N. obtusifolia was characterized by evaluating N. obtusifolia pollen tube growth in normal and TT‐ablated N. tabacum styles at various post‐pollination times and developmental stages. The II activity of the TT slowed and then arrested N. obtusifolia pollen tube growth, and was developmentally synchronized. We hypothesize that proteins produced by the mature TT and secreted into the extracellular matrix inhibit interspecific pollen tubes. When extracts from the mature TT of N. tabacum were injected into the TT‐ablated style prior to pollination, the growth of incompatible pollen tubes of N. obtusifolia and N. repanda was inhibited. The class III pistil‐specific extensin‐like protein (PELPIII) was consistently associated with specific inhibition of pollen tubes, and its requirement for II was confirmed through use of plants with antisense suppression of PELPIII. Inhibition of N. obtusifolia and N. repanda pollen tube growth required accumulation of PELPIII in the TT of N. tabacum, supporting PELPIII function in pre‐zygotic II.     

扬子鳄消化道Ghrelin免疫活性细胞的分布及其在冬眠期的密度变化

目的 研究扬子鳄（Alligator sinensis）消化道中生长素释放肽ghrelin免疫活性（IR）细胞的分布、组织定位及其在冬眠期的变化.方法 应用链霉亲和素-生物素-过氧化物酶复合物（SABC）免疫组织化学方法结合生物统计学分析.结果 Ghrelin-IR细胞在扬子鳄的小胃密度最高,在胃贲门部、胃体和胃幽门部有少量分布,主要位于胃腺上皮细胞之间.在食管、十二指肠、空肠、回肠和直肠中均未检测出ghrelin-IR细胞.冬眠期小胃ghrelin-IR细胞显著性减少（P〈0.01）,其它部位无显著性变化（P〉0.05）.结论扬子鳄消化道ghrelin-IR细胞的分布同其它动物有相似之处,也有其一定的特异性.Ghrelin在扬子鳄冬眠期的代谢变化和能量稳态的调节中起重要作用.     

泌尿系感染常见病原菌的分布及耐药性分析

【摘 要】 目的 探讨解放军第44医院住院患者泌尿系感染病原菌的分布及耐药性,为临床合理应用抗菌药物提供参考。方法 通过法国生物梅里埃VITEK 2 compact及ATB-Expression细菌鉴定分析仪对2012年该院收治的698例住院患者送检中段尿标本进行细菌鉴定,并用K-B法对分离病原菌进行体外药敏试验。结果 698例患者中有512例培养阳性,其中女性患者阳性率为81.5%,男性患者阳性率为19.0%,二者比较差异有统计学意义(P＜0.05)。512例阳性患者中段尿标本中共分离出病原菌536株,其中革兰阴性杆菌占68.8%,革兰阳性球菌占22.8%,真菌占8.4%。分离病原菌对常用抗菌药物呈现多重耐药性,革兰阴性杆菌对氨苄西林、哌拉西林、头孢噻吩、复方新诺明的耐药率高于60.0%,对亚胺培南、阿米卡星敏感。革兰阳性球菌对克林霉素、红霉素、青霉素的耐药率高于70.0%,对万古霉素、替考拉宁高度敏感。结论 泌尿系感染病原菌对常用抗菌药物耐药严重,及时了解泌尿系感染病原菌的分布特点及耐药性,对临床合理选用抗菌药物具有重要意义。     

儿童呼吸道感染时呼吸道分泌物的病原菌分布及其耐药性分析

【摘 要】目的 了解本地区儿童呼吸道感染病原菌种类、分布特点及其耐药性,为临床合理应用抗菌药物提供参考。方法 对2009年5月至2012年5月间本地区两家医院儿科住院患者送检的共1350份呼吸道分泌物的细菌培养结果及要检出菌的耐药情况,进行回顾性分析。结果 从1350份标本中共分离出384株病原菌,检出率为28.4%,革兰阴性杆菌258株,占67.2%,革兰阳性球菌95株,占24.7%,厌氧菌17株,占4.4%,真菌14株,占3.6%;革兰阴性前三位杆菌肺炎克雷伯杆菌、大肠埃希菌和解鸟氨酸克雷白杆菌对氨苄西林、哌拉西林耐药率均大于50%以上,共分离出产ESBLs菌57株,阳性率为43.2%;革兰阳性前三位球菌肺炎球菌、金黄色葡萄球菌和表皮葡萄球菌对青霉素、红霉素耐药率达50%以上。结论 本地区儿童呼吸道感染主要病原菌是革兰阴性杆菌,加强细菌培养和耐药性监测对临床合理使用抗生素有重要意义。     

青年咽部菌群分布状况

目的调查健康青年上呼吸道的微生物群分布,寻找优势菌群,为微生态方法治疗呼吸道感染性疾病提供科学依据。方法随机自愿原则选取沈阳医学院学生61名,采集咽后壁标本分离培养并生化鉴定。结果青年咽后壁共检出19个菌属,42个菌种。需氧菌的95％可信区间为（4．7×10^6,6．8×10^6）CFU／mL,厌氧菌的95％可信区间为（5．9×10^6,8．4×10^6）CFU／mL;需氧菌菌群密度为4．8816±1．0251,厌氧菌菌群密度为5．1347±0．9118。需氧菌中链球菌属检出率为100％,其次为奈瑟球菌属（77．4％）、葡萄球菌属（33．9％）。链球菌中缓症链球菌和口腔链球菌、奈瑟球菌属中的灰色奈瑟球菌的检出率与构成比均较高。厌氧菌中检出率与构成比较高是的韦荣球菌属、拟杆菌属、孪生球菌和放线杆菌属。结论青年上呼吸道菌群种类复杂多样;需氧菌中的口腔链球菌、缓症链球菌、灰色奈瑟球菌,厌氧菌中的韦荣球菌属、拟杆菌属、孪生球菌属为优势菌群,对于维护上呼吸道微生态平衡可能起重要的作用。     

小儿下呼吸道感染痰培养标本病原菌构成分析

目的了解小儿下呼吸道感染病原菌的分布及对常用抗菌药物的耐药状况。方法对2710例小儿下呼吸道感染患者痰标本进行培养,用VITEK-2Compact微生物鉴定系统鉴定菌种和药敏试验,WHO-NET5．4软件对数据进行分析。结果共分离病原菌675株,革兰阴性杆菌457株,占67．7％,主要为大肠埃希菌、肺炎克雷伯菌;革兰阳性球菌159株,占23．5％,主要为金黄色葡萄球菌、肺炎链球菌;真菌59株,占8．7％,主要为白色假丝酵母菌。结论小儿下呼吸道感染病原菌以革兰阴性杆菌为主,耐药性较为严重,应不断加强耐药性监测,合理使用抗菌药物。     

婴儿泌尿道感染的病原菌分布及耐药性分析

目的探讨婴儿泌尿道感染的病原菌构成及其耐药情况,以指导临床合理用药。方法对2012年5月至2013年7月某院门诊及住院婴儿送检的尿标本进行分离培养,用全自动微生物鉴定／药敏系统进行菌种鉴定和药敏试验,同时对大肠埃希菌和肺炎克雷伯菌进行超广谱β-内酰胺酶检测。结果婴儿泌尿道感染以大肠埃希菌检出率最高（46．24％）,其余依次是粪肠球菌（22．04％）、肺炎克雷伯菌（7．80％）、屎肠球菌（5．37％）、铜绿假单胞菌（4．30％）。大肠埃希菌和肺炎克雷伯菌超广谱β-内酰胺酶检出率分别为46．51％和58．62％。革兰阴性菌对亚胺培南、美罗培南的耐药率为0,对氨苄西林耐药率最高（〉80％）。革兰阳性菌对万古霉素耐药率为0,对苯唑西林、妥布霉素的耐药率100％。结论婴儿泌尿道感染病原菌以大肠埃希菌为主;大肠埃希菌、肺炎克雷伯菌超广谱β-内酰胺酶检出率高,应引起重视;临床医师要根据药敏结果指导用药,对危重病例和存在泌尿道畸形反复发作病例,革兰阴性菌可选用亚胺培南、美罗培南,革兰阳性菌可选用万古霉素。     

泌尿生殖道支原体培养及耐药性差异分析

目的检测本地区人群泌尿生殖道溶脲脲原体（Uu）和人型支原体（Mh）感染的发生率;分析其对9种抗生素的药物敏感性差异,用以指导临床的抗生素治疗。方法采用法国生物梅里埃Mycoplasma IST2试剂盒对支原体进行分离培养鉴定和药物敏感性试验;分析2008—2013年本地区支原体感染患者耐药性的差异。结果在本地区8168例疑似NGU的患者中检出支原体2564例,阳性检出率为31．39％,其中仅uu感染的患者1833例（22．44％）,Uu和Mh混合感染的患者623例（7．63％）,仅Mh感染的患者108例（1．32％）。仅uu感染的患者对PRI、JOS、DOT、TET、CLA、AZI、ERY、OFL和CIP九种抗生素的敏感率分别为99．8％、99．4％、96．3％、91．9％、90．O％、89．7％、69．7％、4．O％和0．5％;Uu和Mh混合感染的患者对9种抗生素的敏感率分别为96．3％、96．1％、94．8％、79．5％、12．0％、11．7％、1．4％、1．0％和0．3％;仅Mh感染的患者对9种抗生素的敏感率分别为100％、100％、100％、90．7％、0％、0％、O％、14．8％和13．9％。结论本地区泌尿生殖道支原体感染以Uu感染最为常见,Uu和Mh混合感染次之,Mh感染最为少见;对支原体的抗生素治疗首选PRI、JOS、DOT;TET、AZI、CLA可适当使用,而ERY、OFL、CIP则不宜选用。     

The gastrointestinal tract: A major site of antioxidant action?

Diets rich in fruits and vegetables delay the onset of many age-related diseases, and contain a complex mixture of antioxidants (including ascorbate, carotenoids, vitamin E and other phenolics such as the flavonoids). However, diet also contains pro-oxidants, including iron, copper, H₂O₂, haem, lipid peroxides and aldehydes. Nitrite is frequently present in diet, leading to generation of reactive nitrogen species in the stomach. In considering the biological importance of dietary antioxidants, attention has usually focussed on those that are absorbed through the gastrointestinal tract into the rest of the body. In the present paper we develop the argument that the high levels of antioxidants present in certain foods (fruits, vegetables, grains) and beverages (e.g. green tea) play an important role in protecting the gastrointestinal tract itself from oxidative damage, and in delaying the development of stomach, colon and rectal cancer. Indeed, carotenoids and flavonoids do not seem to be as well absorbed as vitamins C and E. Hence their concentrations can be much higher in the lumen of the GI tract than are ever achieved in plasma or other body tissues, making an antioxidant action in the GI tract more likely. Additional protective mechanisms of these dietary constituents (e.g. effects on intercellular communication, apoptosis, cyclooxygenases and telomerase) may also be important.