发光细菌DH132的筛选、鉴定及其在氯霉素生物毒性测定中的应用

利用药敏纸片法,从本实验室保存的发光细菌中筛选出一株对氯霉素敏感的细菌DH132。通过生理生化特征鉴定并利用16SrDNA序列分析的方法,鉴定细菌DH132为哈维氏弧菌。通过在细菌培养液中添加不同浓度的氯霉素溶液,研究了氯霉素浓度与细菌发光强度抑制率之间的关系。结果表明,当氯霉素浓度为80ng/mL和160ng/mL时,对细菌发光的抑制率分别达到10%和50%。氯霉素浓度在0~60ng/mL,60~140ng/mL,140ng/mL~200ng/mL和200~1000ng/mL之间,细菌发光抑制率与氯霉素浓度分别具有很好的线性关系。相对应的回归方程分别为y=0.0627x-0.0233;y=0.3599x-18.276;y=0.7527x-70.219;y=0.0195x 75.964,回归曲线R2值分别为0.9805,0.9918,0.9502和0.9731。     

大菱鲆出血症病原菌的分离和鉴定

从患病大菱鲆体内分离到一株病原菌SMP1,经人工感染试验计算出SMP1的半致死量LD50 =1.94× 10 6 。药敏实验表明氟哌酸、丙氟哌酸、复合磺胺、氯霉素、四环素对SMP1有较强的抑制作用。BIOLOG细菌鉴定系统不能对SMP1鉴定。综合形态观察、生理生化特征、16SrDNA、溶血素基因保守区分析等实验结果 ,可将SMP1鉴定为鳗弧菌。     

纳米银/聚乙烯醇复合物的生物合成及其对6种水产病原菌的抑菌活性

纳米银作为一种新型抑菌剂有望成为传统抑菌剂的替代品,制备稳定、高效、环保的新型纳米银抑菌产品成为当今的研究热点。本研究以葡萄籽提取液为还原剂和稳定剂,聚乙烯醇(PVA)为载体,采用一步法“绿色”生物合成出一种纳米银/聚乙烯醇复合物(AgNPs/PVA)。通过紫外-可见(UV-Vis)吸收光谱、透射电镜(TEM)、X射线衍射(XRD)等手段对合成产物进行了表征。结果表明银离子被葡萄籽提取物成功还原成纳米银并附着在PVA的表面,纳米银颗粒均匀,呈现单分散状态,粒径较小,平均粒径为14 nm左右。AgNPs/PVA对鳗弧菌、溶藻弧菌、副溶血弧菌、哈维氏弧菌、灿烂弧菌及点状气单胞菌等6种典型的水产病原菌均有显著的抑菌效果。以溶藻弧菌为指示菌,AgNPs/PVA的最小抑菌浓度(MIC)为1.1 μg/mL,最小杀菌浓度(MBC)为2.2 μg/mL。AgNPs/PVA的Zeta电位为?24.1 mV,表明纳米银颗粒间有很强的排斥力,为其稳定分散提供保障,后续实验证明制备的AgNPs/PVA具有良好的稳定性和热稳定性。以上研究结果表明,AgNPs/PVA复合材料在水产养殖病害防治中具有广阔的应用前景。      

PMMA芯光纤侧面发光的制备及表征

选用破坏皮层的溶剂处理PMMA芯端发光光纤,获得所需要侧面发光光纤.通过对各种条件下处理得到的侧发光光纤的发光效果进行表征及分析,结果表明:MMA溶液以及正己烷与丙酮以体积比1:1混合溶液处理得到的侧发光效果较好,发光亮度呈指数衰减曲线.根据实验曲线给出了一个描述基于敏感系数、沿纤维轴向的长度、侧面发光系数等发光参数的基本模型,并利用双光源入射光纤来提高侧发光亮度.这种侧发光光纤的制备方法可应用于光纤可控发光织物及柔性织物显示器.     

导入四碳二羧酸转移酶基因对费氏中华根瘤菌共生固氮效率的影响

将来自苜蓿中华根瘤菌(Sinorhizobium meliloti)的四碳二羧酸转移酶基因(dctABD)经pIJ2925克隆到广宿主、稳定性质粒pTR102上,获得诱导型表达的重组质粒pHN202.在此基础上再引入来自pDB30所含的发光酶基因(luxAB)作分子标记,以pTR102为基础构建成带有dctABD和luxAB的重组质粒pHN205.经三亲本接合转移,将重组质粒pHN205导入费氏中华根瘤菌(Sinorhizobium fredii)HNO1,GR3和YC4.与出发菌相比较的盆栽试验结果表明:HN01(pHN205)和GR3(pHN205)分别在宁镇一号和川早一号大豆上能显著提高植株地上部分干重(生物量)和总氮量, YC4(pHN205)在黑龙33大豆上能同时显著提高植株地上部分干重(生物量),总氮量和根瘤鲜重.本研究结果表明:导入dctABD基因对共生固氮效率的增效性与受体根瘤菌和大豆品种等因素有关.以luxAB为报告基因进行的转移接合子培养条件下分离单菌落和共生条件下形成根瘤的发光活性检测结果表明:pHN205可在供试费氏中华根瘤菌中稳定遗传.     

黑鲷肠道乳酸杆菌的分离与鉴定及其抑菌特性

无菌条件下取黒鲷肠道研磨液在MRS培养基厌氧培养,分离乳酸菌株经鉴定后命名为L-1、L-2,并分别进行两分离株的体外抑菌试验和胞外产物的稳定性研究.结果表明,2株乳酸菌胞外产物对热稳定且对副溶血弧菌有较强抑制作用,可以作为开发海水鱼用微生态制剂的备用菌株.     

高活性几丁质酶产生菌的筛选及鉴定

从四川、陕西、浙江等地食用菌栽培的土壤样品中,筛选到一株性能优良、产几丁质酶活力较强的菌株BLC08609,并结合菌落形态、生理生化指标和16S rDNA序列分析对其进行鉴定.结果显示,菌株BLC08609能以食用菌细胞壁(以几丁质为主)为唯一碳源生长,在菌株BLC08609个体形态和生理生化特性鉴定的基础上,通过16S rDNA测序鉴定,确定BLC08609为地衣芽孢杆菌(Bacillus licheniformis).     

苯中痕量噻吩检测分析研究

苯中痕量噻吩对新工艺下己内酰胺的生产造成影响,工艺要求苯中噻吩控制在0.02mg/kg以下.本文利用气相色谱法(GC)、硫化学发光检测器(SCD),分析检测苯中的痕量噻吩,低浓度下工作曲线的线性相关系数0.9994,检测限0.001 mg/kg,符合ASTM D7011-2015方法要求,满足新型企业生产需要,与相对成...     

厦门海域产蛋白酶浮游细菌的多样性研究

从厦门海域分离筛选到33株产蛋白酶浮游细菌,并通过对其16S核糖体RNA(16S rRNA)基因进行聚合酶链式反应(PCR)扩增和限制性片段长度多态性(RFLP)分析,初步研究了该海域产蛋白酶浮游细菌的多样性.研究发现,这33株菌可分为12种操作分类单元(OTU),其中OTU-Ⅰ和OTU-Ⅱ分别包含8株和12株菌株,分别占总菌数的24.2%和36.4%,为优势分离类群.分别从12种OTU中随机选取1株细菌作为代表进行16S rRNA基因测序.序列分析结果显示,属于OTU-Ⅶ的细菌为假交替单胞菌属(Pseudoalteromonas sp.),而包括OTU-Ⅰ和OTU-Ⅱ在内的9种OTU 都属于弧菌属(Vibrio sp.),表明弧菌在厦门海域产蛋白酶浮游细菌中占优势.初步的生理检测显示,这些细菌的适宜生长温度为16℃左右,适宜生长盐度范围为3%～5% NaCl.     

Pr~(3+)离子激活的新型长余辉发光材料GdY_(1.46)Lu_(0.5)Ga_3Al_2O_(12)∶0.04Pr~(3+)的发光性质研究

通过高温固相法合成了镨掺杂的稀土镓铝石榴石(GdY_(1.46)Lu_(0.5)Ga_3Al_2O_(12)∶0.04Pr~(3+))。利用X射线衍射、荧光光谱、长余辉光谱、荧光衰减曲线和热释光光谱等手段,对样品的发光性质进行了系统的研究。结果表明,在254nm光源的激发下,样品GdY_(1.46)Lu_(0.5)Ga_3Al_2O_(12)∶0.04Pr~(3+)发出黄色的荧光,停止激发后,该样品发出明亮的黄色长余辉。并且,该长余辉能够持续3h以上。     

一株牙Ping出血症病原菌的分子生物学鉴定

从患出血症养殖牙Ping分离到一株病原菌M4,革兰氏阴性,杆状,有极生和侧生鞭毛,能运动,菌落半透明。进行了常规生理生化和BIOLOG－GN细菌鉴定系统测试。结果表明菌株M4与V.carchariae的表型特征非常相似。为了进一步确定M4的分类学地位,测定了其16SrRNA基因序列,分析了相关细菌相应序列的同源性,构建了系统发生树,结果表明菌株M4和V.carchariae的亲缘关系最近。综合上述结果,菌株M4可鉴定为Vibiro carchariae。     

Proposal of an approximation equation for the yield locus to evaluate powder properties

The yield locus (YL) of powder bed can be used to determine many mechanical properties of a powder such as cohesion, unconfined yield stress, stress ratio, etc. Generally, the YL of powder beds is obtained by fitting the results of shear tests to linear approximations based on the Coulomb equation or to curved approximations based on the Warren–Spring equation. Meanwhile, the yielding characteristics of a powder bed are expressed by the Roscoe condition diagram. In this diagram, the YL appears orthogonal to the normal stress axis at both ends corresponding to tensile and compressive strength. However, the YL approximated by the Coulomb or Warren–Spring equations is not orthogonal to the normal stress axis at both ends, and is not the same shape as the YL shown in Roscoe condition diagrams. Thus, the abovementioned mechanical properties obtained from the YL of a powder bed are likely to be affected by the approximate expression for the YL. Despite this, no one has investigated how the mechanical properties of powder beds such as stress ratios are affected by the approximation method for the YL. In this paper, we propose a new approximation equation for the YL that conforms both to the shape of the YL in the Roscoe condition diagrams and experimental results. Then, these YL obtained by our equation, and by the Coulomb and Warren–Spring equations are used to determine the mechanical and flow properties of powder beds. These values are compared with each other in order to discuss the validity of our equation.     

Controlling the yellow luminescence intensity from n-GaN during cathodoluminescence

GaN grown on sapphire by hydride vapour phase epitaxy is probed by ion channeling, Raman and cathodoluminescence (CL) spectroscopy. Channeling and Raman spectroscopy indicate that the quality of GaN is very good. Spot mode CL measurement signifies intense near band edge emission as compared with yellow luminescence (YL). During scanning over an area, the YL intensity could be controlled by the electron beam dwell time (DT). The YL intensity decreases with the increase of DT and saturates beyond a threshold value due to overexposure of a given pixel leading to non-radiative emission. But for shorter dwell times repeated excitations of a given pixel increase the intensity of YL. These results may be explained invoking the decay time and density of defects responsible for YL. Control over YL intensity will be useful for assessing low defect concentrations, their origin and also to increase spatial resolution of CL measurements on nanostructures.     

鳗弧菌金属蛋白酶单克隆抗体的制备及鉴定

鳗弧菌M3胞外产物经纯化得到分子量为36.5kDa的金属蛋白酶，浓缩后作为抗原免疫BALB/C小鼠，经细胞融合及筛选。得到三株稳定分泌抗金属蛋白酶的杂交瘤细胞株。分别命名为P2B1，P4A3和P4B1。亚型鉴定结果表明，三株细胞株产生的单抗均为IgG3型。蛋白质印迹（Wes tern Blot)分析显示，所得到的单抗只与分子量为36.5kDa的金属蛋白酶反应，具有较高特异性。三株单抗均能有效抑制蛋白酶活性。     

牙鲆与大菱鲆病原迟钝爱德华氏菌生物学特性及系统发育学分析

对从7起牙鲆（Bastard halibut,Paralichthys olivaeeus L．）、3起大菱鲆（Turbot,Scophdudmus maximus L．）病害的病（死）鱼中分离到的相应病原菌较系统地进行了形态特征、理化特性等表观分类学指征的鉴定及代表菌株DNA中G＋Cmol％的测定。同时,择代表菌株进行了16SrRNA基因的分子鉴定,测定了16SrRNA基因序列,分析了相关细菌相应序列的同源性,构建了系统发生树。结果表明,分离鉴定的148株菌均为爱德华氏菌属（Edwardsiella Ewing and McWhorter 1965）的迟钝爱德华氏菌（E．tarda）,其中128株为迟钝爱德华氏菌野生型（E．tarda wild type）菌株,20株暂定为迟钝爱德华氏菌吲哚阴性变异株。代表菌株（HC010907—1及HC010830-1）的16SrRNA基因序列,与GenBank数据库中的迟钝爱德华氏菌的同源性均在99％。     

16S rRNA基因与16S-23S rRNA转录单元内间隔区序列分析及其在节旋藻和螺旋藻分类鉴定中的应用

测定了节旋藻属3个品系和螺旋藻属1个品系的全长16SrRNA基因基因和16S rRNA转录单元内间隔区序列（ITS）,分析了已知的节旋藻、螺旋藻和相关品系的相应序列的同源性,构建了系统发生树,并评价了这两段DNA序列在节旋藻、螺旋藻种属分类和种质鉴定中的意义。结果表明：（1）16SrRNA基因序列和ITS序列均可用于节旋藻属和螺旋藻属的属间分类,以两序列为基础的系统学分析结果一致;（2）ITS序列变异程度高于16SrRNA序列,适用于节旋藻和螺旋藻属内品系或种质鉴定;（3）节旋藻属可明确界定,16SrRNA基因序列相似性大于98％,ITS序列相 似性大于88％;（4）螺旋藻属某些品系间16SrRNA序列和ITS序列相似性较低,与不同属间的序列相似性程度为同一水平。     

Synthesis and characterization of nanocrystalline gaN by ammonothermal method using CsNH2 as mineralizer

Nanocrystalline GaN was ammonothermally synthesized at 430 degrees C with CsNH2 as mineralizer. X-ray powder diffraction (XRD) analysis showed that the nanocrystalline GaN were of hexagonal structure. The average diameter of nanocrystalline GaN was about 4.5 nm according to Scherer's formula using the full-width at half-maximum (FWHM) of the (110) peak. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) observation confirmed the size distribution and phase state of the GaN nanocrystals. The calculated lattice parameters obtained both from XRD and High-Resolution Transmission Electron Microscopy (HRTEM) were a = 3.197 A, c = 5.195 A, which were larger than the highly crystallized GaN bulk crystal. Room temperature photoluminescence (PL) measurement exhibited a weak band-edge emission at about 390 nm (3.18 eV), indicating an obvious red-shift from the bandgap of bulk GaN (3.39 eV). A green luminescence (GL) emission located at 485 nm (2.56 eV) and a yellow luminescence (YL) defect-related emission peak centered at 553 nm (2.24 eV) were also observed. The advantage of using CsNH2 as mineralizer for growth GaN, the possible origins of the red-shift of bandgap, YL and GL band were discussed. The red-shift of the bandgap of the as-synthesized GaN nanocrystals was possibly attributed to the expansion of lattice parameters.     

五个紫菜品系间遗传差异的RAPD分析

应用随机引物扩增片段多态性（RAPD）技术对2种紫菜的5个品系进行遗传多样性分析。共筛选出21条随机引物,PCR反应得到147条扩增片段。根据共享扩增片段计算遗传相似性指数（F）和相对遗传距离,利用NJ法构建系统树。结果表明,条斑紫菜或坛紫菜的养殖品系首先聚类在一起,两个条斑紫菜养殖品系之间的遗传距离是0．32,两个坛紫菜养殖品系之间的遗传距离是0．31。条斑紫菜养殖品系CPY1－08A与坛紫菜养殖品系CPH8－83之间的遗传距离最大,达0．42。本文结果显示RAPD可以作为简便有效的分子工具应用于紫菜的遗传多样性和种质鉴定研究中。     

Morphological, structural and optical properties of GaN grown on porous silicon/Si(100) substrate

In the present paper, we report results of GaN layers grown at 800 °C by metal organic vapour phase epitaxy (MOVPE) on porous silicon (PS) formed on Si(100) substrates. The surface morphology and the crystallinity of the GaN films were characterized by scanning electron microscope and X-ray diffraction. It was shown that GaN grows on PS preferentially on hexagonal polycrystalline form. The SEM observation reveals roughly surface textured by disoriented GaN grains having different shapes and sizes. The surface coverage and the wetting of GaN to PS are improved when the thickness of GaN layer increases. The optical properties of GaN layers were examined by PL and CL at low and room temperatures. Besides, the near edge-band (BE) emission, shows yellow (YL) and deep localized excitons bands at approximately 2.2 and 3.3-3.36 eV respectively. The depth CL analysis shows a spatial variation of the dominating YL and BE emissions as the electron beam energy rises from 3 to 25 kV.     

海洋有益菌的筛选与鉴定

从健康的斑节对虾（Penaeus monodon）幼体及其养殖环境中分离到213株海洋细菌,采用十字叉划线法和琼脂扩散法进行体外拮抗试验,从中筛选到5株对水产养殖动物病原哈维氏弧菌（Vibro harueyi）和鳗弧菌（Vibrio anguillarum）等菌株生长有抑制作用的海洋细菌。根据其形态特征以及生理生化反应特征,初步鉴定为交替单胞菌属（Alteromonas）,其中菌株A18鉴定为橙色交替单胞菌（Alteromonas aurantia）。