几何非光滑生物体表形态的分类学研究   总被引：20，自引：0，他引：20  

丛茜  任露泉  吴连奎  陈秉聪  李安珙  胡阿林 《农业工程学报》1992,8(2):7-12

生物体表几何非光滑的实地观察分析和分类,是非光滑表面减粘降阻仿生研究的基础环节之一。本文在实地观察、采集大量粘湿环境土壤动物的基础上,利用电镜分析技术,根据表面几何形态的不同,全面地进行了典型生物体表非光滑形态的分类研究,并以生态学的观点初步探讨了其形成机理。  相似文献   

Effect of cell surface characteristics on the adhesion of bacteria to soil particles     

F. Huysman  W. Verstraete 《Biology and Fertility of Soils》1993,16(1):21-26

Summary We investigated the adhesion to a sandy soil and a clay loam soil of a series of Lactobacillus strains with various cell surface characteristics. Measurable adhesion occurred within 30 s of contact time. No further increase in the number of bacteria adhering to the soil was observed after 15–20 min. The fraction of bacteria adhering to the soil was independent of the initial concentration of bacteria in solution. Bacteria adhering to the soil could be removed by washing the soil immediately after the adhesion test. Bacterial cell surface hydrophobicity, as determined by the bacterial adherence to octane and polystyrene, was the major parameter influencing the adhesion to the sandy soil. The cell surface charge of the bacteria was of minor importance in the adhesion to the sandy soil. The adhesion of the bacteria to the clay loam soil was higher than to the sandy soil and increased in the presence of divalent ions. This indicates that electrostatic interactions also influence the adhesion of bacteria to clay particles.  相似文献   

乳杆菌、双歧杆菌和大肠杆菌附着固定化猪小肠粘液蛋白的研究   总被引：2，自引：0，他引：2  

高巍  孟庆翔 《中国农业科学》2004,37(4):609-609

 采用固定化猪小肠粘液蛋白模型,结合细菌同位素标记方法,对来源于猪胃肠道的乳杆菌、双歧杆菌和大肠杆菌附着活性以及细菌表面凝集素和粘液蛋白的受体的化学组成进行了初步研究。结果表明,乳杆菌、双歧杆菌和大肠杆菌均可附着于固定在细胞培养板上的猪小肠粘液蛋白上,且乳杆菌和双歧杆菌的相对附着数量比大肠杆菌高。3种菌经高碘酸钠和蛋白水解酶修饰后的附着试验表明,大肠杆菌和乳杆菌在粘液蛋白上的附着数量显著降低(P<0.01),推测细菌表面的凝集素为具糖蛋白性质的物质;而化学和酶修饰对双歧杆菌的附着活性没有明显影响。粘液蛋白经蛋  相似文献   

Finger-jointing green softwood: Evaluation of the interaction between polyurethane adhesive and wood     

《Wood material science & engineering》2006,1(3):127-137

Existing European standards for finger-jointing of load-bearing lumber require the wood to be dried before gluing. This article presents a study on the properties of green-glued finger joints, wet wood being bonded prior to drying. Issues to consider, in comparison to finger-jointing of dry wood, are mechanical performance of the joint, absorption of the polymer by the wood in its natural/wet state, and the chemical reactions of the adhesive on contact with water. Finger-jointed samples were tested in bending, and the glue joints analysed by optical microscopy, scanning electron microscopy and microdensitometry. A patented one-component polyurethane adhesive developed for gluing-green wood which has a moisture content usually higher than 70% was used in the study. The resulting green-glued joints showed improved strength properties in comparison to dry-jointed joints. The results confirm that green-glued joints provide a wide, continuous wood/adhesive interface from one substrate to the other. The adhesive penetrates several cells deep and the density of the wood adjacent to the joint surfaces is increased. The results also indicate that the patented adhesive forms covalent bonds to the wood substrate.  相似文献   

松软地面机械仿生理论与技术   总被引：28，自引：7，他引：21  

任露泉  佟金  李建桥  陈秉聪 《农业机械学报》2000,31(1):5-9

生物经过长期与自然环境进行物质、能量及信息交换,造就了适应生态环境的生物系统和生存本领许多科学技术难题在生物界已经获得圆满解决。现代侧试技术和测试仪器的出现使得对生物结构、生物功能和生命过程的认识得到了惊人的进展,这为其他学科的研究及发展注入了新的活力,提供了全新的科学原理和技术方法。在工程科学领域中融入生物科学原理和方法进行生物科学与工程科学渗透交融的工程仿生学研究获得了长足的发展,生物科学、机  相似文献   

高温对家蚕蛾粘液腺生长发育及产附性的影响   总被引：2，自引：1，他引：1  

林金明  吴维光 《蚕业科学》1992,18(1):12-19

试验了高温(五龄蚕31℃,蛹期34℃)对家蚕蛾粘液腺生长发育及产附性的影响。结果表明,高温导致粘腺长度缩短、干重减轻、腺体畸形;支部(分泌部)脆质中粗面内质网和线粒体数量减少,形态被破坏。粘液中的蛋白质及其氨基酸组成改变、含量减少是导致粘着力下降及产附性劣化的直接原因。二化性品种比多化性品种更易受高温影响。  相似文献   

Staphylococcus pseudintermedius expresses surface proteins that closely resemble those from Staphylococcus aureus     

Joan A. Geoghegan  Emma J. Smith  Pietro Speziale  Timothy J. Foster   《Veterinary microbiology》2009,138(3-4):345-352

Staphylococcus pseudintermedius is a commensal of dogs that is implicated in the pathogenesis of canine pyoderma. This study aimed to determine if S. pseudintermedius expresses surface proteins resembling those from Staphylococcus aureus and to characterise them. S. pseudintermedius strain 326 was shown to adhere strongly to purified fibrinogen, fibronectin and cytokeratin 10. It adhered to the α-chain of fibrinogen which, along with binding to cytokeratin 10, is the hallmark of clumping factor B of S. aureus, a surface protein that is in part responsible for colonisation of the human nares. Ligand-affinity blotting with cell-wall extracts demonstrated that S. pseudintermedius 326 expressed a cell-wall anchored fibronectin binding protein which recognised the N-terminal 29 kDa fragment. The ability to bind fibronectin is an important attribute of pathogenic S. aureus and is associated with the ability of S. aureus to colonise skin of human atopic dermatitis patients. S. pseudintermedius genomic DNA was probed with labelled DNA amplified from the serine-aspartate repeat encoding region of clfA of S. aureus. This probe hybridised to a single SpeI fragment of S. pseudintermedius DNA. In the cell-wall extract of S. pseudintermedius 326, a 180 kDa protein was discovered which bound to fibrinogen by ligand-affinity blotting and reacted in a Western blot with antibodies raised against the serine-aspartate repeat region of ClfA and the B-repeats of SdrD of S. aureus. It is proposed that this is an Sdr protein with B-repeats that has an A domain that binds to fibrinogen. Whether it is the same protein that binds cytokeratin 10 is not clear.  相似文献   

Finger-jointing green softwood: Evaluation of the interaction between polyurethane adhesive and wood     

《Wood material science & engineering》2013,8(3-4):127-137

Abstract

Existing European standards for finger-jointing of load-bearing lumber require the wood to be dried before gluing. This article presents a study on the properties of green-glued finger joints, wet wood being bonded prior to drying. Issues to consider, in comparison to finger-jointing of dry wood, are mechanical performance of the joint, absorption of the polymer by the wood in its natural/wet state, and the chemical reactions of the adhesive on contact with water. Finger-jointed samples were tested in bending, and the glue joints analysed by optical microscopy, scanning electron microscopy and microdensitometry. A patented one-component polyurethane adhesive developed for gluing-green wood which has a moisture content usually higher than 70% was used in the study. The resulting green-glued joints showed improved strength properties in comparison to dry-jointed joints. The results confirm that green-glued joints provide a wide, continuous wood/adhesive interface from one substrate to the other. The adhesive penetrates several cells deep and the density of the wood adjacent to the joint surfaces is increased. The results also indicate that the patented adhesive forms covalent bonds to the wood substrate.  相似文献   

东海绿鳍马面鲀产卵群体结构和产卵场调查     

郑元甲  甘金宝  朱善央  姚文祖 《水产学报》1987,11(2):121-134

1.东海绿鳍马面鲀产卵群体自从开发利用以来,体长、年龄和体重组成出现了两次增大两次变小的过程。即1974—1976年和1981—1983年的个体较大,1977—1980年和1984年的个体较小,而1985年的个体最小。但性腺成熟系数却在提高,表明资源的密度在降低。 2.绿鳍马面鲀不同生活阶段的性比不一样,产卵期雄鱼的比例最高,越冬期居次,索饵期雌雄比例基本相等。 3.从产卵个体、仔稚鱼和产卵盛期渔获量的分布判断东海绿鳍马面鲀的产卵场在25°30′—30°00′N、122°00′—126°30′E海区,范围较广,主要产卵场在25°45′—27°00′N、122°00′—123°30′E,水深100—120米的海区。 4.东海绿鳍马面鲀的产卵期在3月底至5月下旬,4月中下旬为产卵盛期。 5.从雌鱼性腺V_A、V_B期比例的周日变化判断绿鳍马面鲀产卵的主要时间在23时至翌日11时。 6.从绿鳍马面鲀人工授精卵附着实验的结果和产卵场环境条件的对照,说明海洋里的贝砾类、海藻、海绵体和珊瑚等物体是马面鲀卵的良好附着基。  相似文献   

汽车附着系数比较分析     

吴心平  赵清华  贾振华 《拖拉机与农用运输车》2014,(1):29-32

附着系数是《汽车理论》课程中的重要概念。在对汽车附着系数进行分析时,首次提出以汽车制动工况和驱动工况两种状态时的附着系数进行对比分析,以便解析附着系数内涵,促进对附着系数相关概念的理解。  相似文献