Influences on the antimicrobial activity of surface-adsorbed nisin

The efficacy of the antimicrobial peptide nisin was examined after adsorption to silica surfaces. Three protocols were used to evaluate nisin's activity against adhered cells ofListeria monocytogenes: bioassay usingPediococcus pentosaceous FBB 61-2 as the sensitive indicator strain; visualization and enumeration of cells by microscopic image analysis; and viability of adhered cells as determined by lodonitrotetrazolium violet uptake and crystallization. The activity of adsorbed nisin was highly dependent upon conditions of adsorption. The highest antimicrobial activity of adsorbed nisin occurred with high concentrations of nisin (1.0 mg ml^–1) and brief contact times (1 h) on surfaces of low hydrophobicity. Sequential adsorption of a second protein (-lactoglobulin or bovine serum albumin) onto surfaces consistently resulted in decreased nisin activity. These data provide direction for the development of applications to limit microbial attachment on food contact surfaces through the use of adsorbed antimicrobial peptides.     

Dynamics of Forest Landscape Patterns Along the Main Road in Xishuangbanna

In this paper, we investigated dynamics of forest landscape along the main roads in Xishuangbanna from 1976 to 1988, and from 1988 to 2003, using FRAGSTATS software and the GIS technology, based on the results interpreted from the Landsat MSS TM ETM imageries in 1976, 1988, 2003. Some representative quantitative indices of landscape diversity, including mean patch area, percent of landscape , perimeter-area fractal dimension , aggregation , Shannon′s diversity index , and Shannon′s equality index were used to describe the changes in the spatial pattern of landscape elements. Comparing with whole region of Xishuangbanna during last 27 years , the results showed that the man-made landscape (rubber plantation) and non-forested landscape along the main road expanded faster and their percentage were greater, whereas the natural landscape ( primitive forest patches) reduced faster and its percentage was smaller . There were obviouseffects of road on landscape which the forest coverage was decreased , and rubber plantation landscape was increased with the distance from the road . The natural forest landscape had been fragmented. Especially, the tropical seasonal rain forest was affected severely, while the area and contagion of rubber plantation and shrub increased. The whole landscape pattern along the main road tended to be diversiform, equal and fragmented. The landscape was still dominated by natural landscapes but this dominance was weakening . A case study about the displacement of landscape patch centroids showed that the spatial centroids of many types of landscape, including rubber plantation, tropical seasonal rain forest, mountain rain forest, shrub and non-forested land had moved away from the road. All of these changes in landscape pattern would lead the deterioration of these region environments.     

KRAB型锌指蛋白在高等脊椎动物胚胎发育和肿瘤发生、发展中的调控功能

KRAB型锌指蛋白(KRAB-ZFPs)最早出现于四足类脊椎动物, 且进化非常迅速, 是人类基因组编码的最大转录因子家族。尽管当前对此家族蛋白发挥调控功能的分子机制已有较为深入的研究, 但关于此家族蛋白所具备的高等脊椎动物特有的调控功能目前尚无全面系统的认识。文章对KRAB型锌指蛋白在高等脊椎动物的胚胎发育及肿瘤发生、发展中发挥的调控功能进行综述, 以期丰富对该家族蛋白在不同生理、病理过程中调控功能的认识, 为今后更深入的理论和应用研究打下坚实基础。     

基于温度-伤害度关系分析酿酒葡萄根系及芽抗寒性

采用差热分析系统(DTA)对8个主栽酿酒葡萄品种的芽和根系进行低温放热分析(LTE),建立各品种芽、根系韧皮部及木质部的温度-伤害度(LT-I)回归方程,评估不同品种的根系及芽抗寒性.结果表明： 8个品种的根系韧皮部伤害度50%的温度从高到低为马瑟兰>品丽珠>赤霞珠>小芒森>霞多丽>蛇龙珠>贵人香>熊岳白;不同品种木质部伤害度50%的温度从高到低为马瑟兰>霞多丽>赤霞珠>小芒森>品丽珠>蛇龙珠>贵人香>熊岳白;芽伤害度50%的温度从高到低为赤霞珠>小芒森>蛇龙珠>品丽珠>霞多丽>贵人香>马瑟兰>熊岳白.利用模糊隶属函数值法综合评价根系及芽的抗寒性,马瑟兰根系的抗寒性最差,熊岳白根系的抗寒性最好;赤霞珠、品丽珠、小芒森和蛇龙珠芽的抗寒性最差,贵人香和熊岳白芽的抗寒性最好.     

Relics of the Europe's warm past: phylogeography of the Aesculapian snake

Understanding how species responded to past climate change can provide information about how they may respond to the current global warming. Here we show how a European reptile species responded to the last natural global warming event at the Pleistocene-Holocene transition that led to the Holocene climatic optimum approximately 5000-8000 years ago. The Aesculapian snake, Zamenis longissimus, is a thermophilous species whose present-day distribution in the southern half of Europe is a remnant of much wider range during the Holocene climatic optimum when populations occurred as far north as Denmark. These northern populations went extinct as the climate cooled, and presently the species is extinct from all central Europe, except few relic populations in locally suitable microhabitats in Germany and the Czech Republic. Our phylogenetic and demographic analyses identified two major clades that expanded from their respective western and eastern refugia after the last glacial maximum (18,000-23,000 years ago) and contributed approximately equally to the present range. Snakes from the relic northern populations carried the Eastern clade, showing that it was primarily the snakes from the eastern, probably Balkan, refugium that occupied the central and northern Europe during the Holocene climatic optimum. Two small, deep-branching clades were identified in near the Black Sea and in Greece. These clades provide evidence for two additional refugia, which did not successfully contribute to the colonization of Europe. If, as our results suggest, some populations responded to the mid-Holocene global warming by shifting their ranges further north than other populations of the same species, knowing what populations were able to expand in different species may provide information about what populations will be important for the species' ability to cope with the current global warming.     

球蚧跳小蜂属一新种记述(膜翅目,跳小蜂科)

记述采自辽宁省沈阳市北陵公园云杉球蚧Physokermes sp.上的跳小蜂1新种:云杉球蚧跳小蜂Aphycoides marginalis sp.nov.,所有模式标本均保存于东北林业大学昆虫标本室.     

机械通气患儿气管导管表面细菌生物膜形成及病原分析

目的观察儿科重症监护病房（PICU）机械通气（mechanical ventilation,MV）患儿气管导管（endotraeheal tube,mr）表面细菌生物膜（biofilm,BF）内细菌分布情况及BF形态学特征。方法以我院治疗的35例MV患儿为研究对象。收集第1次拔除或更换的ETT,经碘化丙啶（PI）和异硫氰酸荧光索标记刀豆蛋白A（FITC-ConA）染色后,激光共聚焦显微镜观察ETT-BF内细菌及胞外多糖（EPS）分布情况,并收集ETT表面和下呼吸道分泌物进行细菌分离、培养和鉴定。结果（1）35例MV患儿中,E1-r表面细菌培养阳性31例（88．57％）;17例EIT表面和下呼吸道分泌物同时分离出相同菌种,占ETT培养阳性的54．83％。在EIT-BF和下呼吸道分泌物中以金黄色葡萄球菌,肺炎克雷伯菌,大肠埃希菌,阴沟肠杆菌最常见。（2）CLSM观察可见,气管插管12h后,ETT-11表面已出现细菌黏附;48h时ETT表面可见大量短棒状或球状细菌黏附聚集,EPS较12h时显著增多,初步形成BF结构;72h左右细菌粘连成团块状,被EPS包裹,可见成熟BF结构形成;7d后细菌粘连成大片状,在其周围可见散在的微菌落。（3）35例MV患儿中,19例发生了呼吸机相关性肺炎（ventilated—associated pneumonia,VAP）。其中经口插管10例,经鼻插管9例。结论MV时细菌极易在ETT表面黏附,形成细菌BF。ETF表面细菌定植及BF形成与长时间MV患儿伴发呼吸机相关性肺炎之间可能存在一定相关性。     

多次采血对Wistar大鼠脏器系数的影响

目的研究不同时间间隔经眼眶静脉丛多次采血后,对雄性Wistar大鼠重要脏器系数的影响。方法实验组分别间隔3 d、7 d、10 d,经眼眶静脉丛采血,每次采血1 mL,共采3次。对照组于实验组最后一次采血时采血一次,采血1 mL。每次采血前称量体重,于最后一次采血后将大鼠处死,取心脏、肝脏、肾脏、脾脏、胸腺,称量脏器重量,计算脏器系数。结果间隔3 d多次采血,大鼠的肝、肾系数差异具有显著性（P〈0.05）,间隔7 d、10 d多次采血,大鼠的各脏器系数差异无显著性。结论间隔3 d多次采血对大鼠的肝、肾系数有影响,间隔7 d、10 d多次采血对各脏器系数均无影响。     

新革螨属2新种记述（蜱螨亚纲：中气门目：寄螨科）

记述新革螨属2新种：双锯新革螨Neogamasus biserrendogynii sp．nov．和双瓣新革螨Neogamasus bivalvendogynii sp．nov．。     

降落伞式缝合在肠道吻合术中的应用

目的：通过胆肠吻合缝合技术的改进,减少并发症的发生。方法：对52例肠道吻合手术采用降落伞式缝合。结果：降落伞式胆肠吻合时间平均20min,明显缩短了手术时间,全部病例均未出现胆肠吻合漏,无死亡病例。结论：降落伞式胆肠吻合术具有操作简便、省时、并发症少等特点。