Biochemical Changes in Microbe-free Silage

㊀第40卷㊀第11期2021年11月中国材料进展MATERIALS CHINAVol.40㊀No.11Nov.2021收稿日期:2020-02-23㊀㊀修回日期:2020-05-04基金项目:国家自然科学基金项目(81722015,81870805,81870787);陕西高校青年创新团队项目第一作者:王婉蓉,女,1992年生,医师秦㊀雯,女,1998年生,在读本科生(八年制)通讯作者:牛丽娜,女,1983年生,教授,博士生导师,Email:niulina831013@ 焦㊀凯,男,1982年生,副教授,博士生导师,Email:kjiao1@DOI :10.7502/j.issn.1674-3962.202002009细菌介导生物矿化的研究进展王婉蓉1,秦㊀雯1,顾俊婷1,郑秀丽1,唐笑怡2,焦㊀凯1,牛丽娜1(1.军事口腔医学国家重点实验室口腔疾病国家临床医学研究中心陕西省口腔医学重点实验室第四军医大学口腔医院修复科,陕西西安710032)(2.中国人民解放军联勤保障部队第九二ʻ医院(昆明医科大学教学医院),云南昆明650032)摘㊀要:生物矿物因其高度有序的结构和良好的机械性能成为诸多学科研究的热点㊂对细菌㊁真菌㊁病毒等微生物介导生物矿化的深入研究,不仅能使学者更加系统地认识生命演化过程,而且能为新材料的研发提供思路㊂其中,细菌诱导的矿化因其潜在的应用价值而深受研究者的青睐㊂首先介绍了细菌介导的钙化㊁硅化㊁铁矿化3种不同的生物矿化类型,其次讨论了细菌介导生物矿物形成的可能机制,最后阐述了生物矿物在环境㊁工业及医疗领域的应用,为进一步的生物矿化研究奠定基础㊂关键词:生物矿化;生物矿物;细菌;环境;工业;医药中图分类号:R783.1㊀㊀文献标志码:A㊀㊀文章编号:1674-3962(2021)11-0930-08Progress of Bacteria-Mediated BiomineralizationWANG Wanrong 1,QIN Wen 1,GU Junting 1,ZHENG Xiuli 1,TANG Xiaoyi 2,JIAO Kai 1,NIU Lina 1(1.State Key Laboratory of Military Stomatology &National Clinical Research Center for Oral Diseases &Shaanxi Key Laboratory of Stomatology &Department of Prosthodontics,School of Stomatology,The Fourth Military Medical University,Xi a n 710032,China)(2.Kunming Medical University,920th Hospital of Joint Logistics Support Force,Kunming 650032,China)Abstract :Biominerals have become hotspots in many disciplines due to their highly ordered structure and good mechanicalproperties.The research on microbe-mediated biomineralization can help us to understand the evolution process of life more systematically,and provide new ideas for the development of new materials.Among them,bacteria-mediated biomineraliza-tion is favored by researchers for its potential value.Firstly,this article introduces the processes of calcification,silicifica-tion and iron mineralization induced by bacterial.Then,we discuss the possible mechanisms for bacterial-mediated biologi-cal mineral formation.Finally,we describe the application of biominerals in the environmental,industrial,and medical fields.It is expected that this study may help the further development of biomineralization.Key words :biomineralization;biominerals;bacterial;environment;industry;medicine1㊀前㊀言生物矿化是指生物体通过蛋白质等生物大分子调控无机矿物形成的过程㊂在此过程中形成的具有纳米级结构的生物矿物,不仅具备极佳的强度和断裂韧性,也呈现出良好的生物相容性㊂迄今为止,已从生物中鉴定出60多种不同的矿物质㊂这些矿物对于自然界的物质循环起着重要作用[1]㊂细菌作为自然界最活跃的微生物之一,在生物矿物的形成中发挥着重要的作用㊂目前已经发现了大量由细菌介导生成的矿物,例如有研究发现嗜盐菌及枝芽孢菌可以促进白云石的形成;球形芽孢杆菌有助博看网 . All Rights Reserved.㊀第11期王婉蓉等:细菌介导生物矿化的研究进展于碳酸钙晶体的形成[2]㊂细菌介导的矿化与生命演变息息相关㊂在原始环境下最早出现的是原核生物矿化,这表明细菌-矿物相互作用是生命史早期的一个重要现象㊂这种相互作用对于古老地球环境的研究以及寻找其他行星表面生命都有着重大意义[3]㊂当外界环境转变至有利于矿化发生时,细菌通常有着多种不同的应答方式,例如通过形成生物膜避免被矿化或在保存细菌活性的前提下嵌入矿物中,甚至可在矿物形成过程中控制其形态㊂此种现象说明细菌的进化与周围环境的改变息息相关[4]㊂相比于化学合成的方式,细菌合成矿物不仅绿色经济环保,且操作较为方便,因此细菌介导的生物矿化在环境净化㊁工业生产和医药研究等领域的潜在应用已成为目前研究的热点㊂例如一些由微生物矿化引起的疾病有可能通过对细菌的干预进而治愈[5];由于生物矿物具有良好的生物相容性,因此可作为药物载体应用在肿瘤疾病的靶向治疗中[6];除此之外,可通过化学交联和基因编辑等方式修饰细菌蛋白,使生物矿物的形态和大小根据工业需要进行合成[7]㊂本文综述了细菌介导生物矿化的类型㊁作用机理及应用,为进一步的生物矿化研究提供参考㊂2㊀细菌介导生物矿化的类型2.1㊀钙化细菌介导的钙化存在于天然矿物和生物体内㊂研究发现好氧菌如Salinivibrio和Virgibacillus有助于MgCa-(CO3)2的形成,而MgCa(CO3)2被认为是天然矿物白云石的前体[8]㊂甲壳类动物㊁海洋生物㊁植物甚至人体组织均可见由细菌介导的钙化发生㊂甲壳类动物是指虾㊁蟹等有坚硬外壳保护的动物,其外壳由甲壳质㊁结合蛋白和碳酸钙构成,具有排泄㊁感知和保护的作用[9]㊂研究发现甲壳类动物Titanethes albus的钙体内存在大量细菌,且钙体的中心存在结晶晶核[10]㊂海绵是一种海洋无脊椎动物,体内存在多种钙化细菌,这些细菌可产生钙化小球覆盖在海绵表面,模拟外周骨骼结构,保护海绵免受外界的伤害,从而提高海绵存活率[9,11]㊂细菌介导的钙化也存在于人体组织中㊂有研究证实尿路结石的发生可能与假单胞菌㊁乳酸菌及肠杆科菌有关㊂细菌导致尿路结石产生的可能机制有以下3种:细菌选择性地聚集在草酸钙晶体上使钙盐增长变快;细菌释放柠檬酸裂解酶,降低尿液中柠檬酸水平的同时提高草酸盐浓度,从而导致尿液过饱和,致使结晶形成;细菌-晶体聚集体可与肾小管上皮结合,导致肾小管上皮或炎性细胞中结石基质蛋白的表达,从而形成结石[5]㊂细菌诱导的钙化也可发生在极端环境下㊂Planococcus halocryophilus Or1在-15ħ时可使调控碳酸钙矿化的碳酸酐酶表达升高,导致更多的碳酸钙沉积在细菌细胞膜中[12]㊂2.2㊀硅化除钙化之外,细菌亦参与了自然界的硅化过程㊂据报道,在ImawarìYeuta洞穴中发现的无定形二氧化硅是由丝状细菌蓝藻介导产生的㊂蓝藻的代谢产物使洞穴环境pH值升高,致岩石溶解㊂溶解产生的二氧化硅可在细菌细胞膜上以无定形的形式重新沉淀[13],形成管状及丝状的岩石结构㊂另外,蓝藻的硅化作用有助于化石在形成过程中保存完好的细胞结构,使考古学家可以获得更多有关古生物的生命信息[14]㊂2.3㊀铁矿化多种细菌都可介导产生四氧化三铁(Fe3O4)和硫化铁(Fe3S4㊁Fe1-x S㊁Fe9S8),其中趋磁细菌(magnetotactic bacteria,MTB)是目前研究的热点㊂MTB是一种能够沿着地球磁场运动或排列的原核生物[15]㊂目前已知的多数MTB属于α-蛋白菌㊁δ-蛋白菌㊁γ-蛋白菌和硝化螺菌类[16],均为革兰氏阴性细菌,有球形㊁弧形㊁杆形及螺旋形等多种形态㊂MTB中负责趋磁运动的细胞器是由细菌生物矿化合成的磁小体㊂磁小体由脂质双分子膜包裹的纳米级磁铁矿晶体构成[17],是淡水沉积物中的重要天然磁性元素㊂这些磁性纳米晶体具有粒度均一㊁纯度高㊁磁性强和生物相容性良好等特点㊂磁性纳米颗粒在自然界中发挥着重要作用㊂由于产生胶黄铁矿的MTB需要硫才能合成磁小体,因此胶黄铁矿被认为是地质历史上停滞缺氧状态(一种无氧状态,由于游离H2S水平升高而呈硫化物状态)的指标[18]㊂此外,在微生物的进化过程中,环境中氧气的出现给微生物带来了源于活性氧的毒性,而嗜热性嗜酸菌Sulfolobus solfa-taricus能够通过氧化作用将Fe2+氧化成Fe3+形成铁矿物,这可以认为是原始生命对于氧气环境的适应[19]㊂另外人体组织中的磁性纳米颗粒与众多疾病的发生发展有关㊂有研究在多种人体器官中均发现了磁性纳米颗粒的存在,其中小脑和脑干分布较多[20]㊂由于这些磁性颗粒与MTB 产生的晶体较为相似,因此被认为其来源为MTB㊂研究发现磁性氧化铁纳米颗粒在中枢神经系统细胞(尤其是星形胶质细胞)的过度积累可能导致正常的铁代谢紊乱,这是神经退行性疾病产生的一个标志性特征,但具体的机制有待于更进一步的研究[21]㊂3㊀细菌介导生物矿化的发生机制自然界的生物矿化可分为生物诱导矿化和生物控制矿化㊂生物诱导矿化是由生物的生理代谢活动引起环境139博看网 . All Rights Reserved.中国材料进展第40卷条件变化而发生的矿化,其中,生物不能直接控制沉淀物的产生位置或产生方式(图1a)㊂生物控制矿化是由生物的生理活动引起的,可产生高度有序的沉淀物,且沉淀物大小㊁质地和方向受生物体控制(图1b)[22]㊂图1㊀生物诱导矿化(a)和生物控制矿化(b)的示意图[22]Fig.1㊀Schematic representation of biologically induced mineralization (a)and biologically controlled mineralization (b)[22]㊀㊀根据发生位置的不同,细菌介导的矿化可分为细胞外矿化和细胞内矿化㊂细胞外矿化是指发生在细胞周围基质中的矿化㊂细胞可通过细胞膜上的蛋白质将阳离子泵出,或通过分泌含有阳离子的囊泡,介导周围基质的矿化㊂细胞内矿化则是指由细胞的代谢活动介导的胞内囊泡矿化㊂细胞内矿化的产物可以存在于细胞内(如MTB),也可以通过胞吐作用释放到胞外(如硅藻)㊂矿化的基本化学反应过程为羧基㊁磷酸基团㊁胺基和羟基等带负电荷的基团与金属阳离子结合,形成矿物㊂以钙化物羟基磷灰石(hydroxyapatite,HAP)为例,其基本的化学反应过程如下:10Ca(OH)2+6H 3PO 4ңCa 10(PO 4)6(OH)2+18H 2O3.1㊀细胞外矿化3.1.1㊀初始矿化细胞外矿化发生的首要条件是细菌周围有足够的可溶性离子㊂研究发现,细菌可通过多种不同机制增加可溶性离子的浓度,例如大肠杆菌在碱性磷酸酶的作用下可以释放磷酸根离子[23],浮生细菌可以通过分泌酸(羧酸㊁盐酸等)降低环境中的pH 值,从而溶解无机磷酸盐㊁增加可溶性离子[24]㊂初始矿化阶段可由经典结晶理论和非经典结晶理论来解释(图2)[25]㊂经典结晶理论认为,成核是相变的开始,这个过程是不可逆的㊂在细菌矿化过程中,成核位点位于胞外聚合物(extracellular polymeric substances,EPS)或细菌表面蛋白质上㊂EPS 由细菌分泌的大分子构成,包含了多糖㊁蛋白质㊁DNA㊁脂类等物质㊂由于EPS 中的大分子物质含有羧基㊁磷酸基团㊁胺基和羟基等带负电荷的基团,EPS 降解后,可与局部过饱和的阳离子相互结合引起矿物沉淀[26]㊂当成核位点位于细菌表面蛋白质上时,金属阳离子如铁离子可直接与细菌表面蛋白质中的羧基和羟基反应,通过金属氧化反应形成金属-蛋白质复合物[27]㊂图2㊀经典结晶理论及非经典结晶理论示意图[25]Fig.2㊀Schematic diagram of classical nucleation theory and non-classical nucleation theory [25]239博看网 . All Rights Reserved.㊀第11期王婉蓉等:细菌介导生物矿化的研究进展㊀㊀而非经典结晶理论认为晶体的形成是以粒子为媒介,由动力学控制的㊁与相分离无关的结晶过程㊂在溶液中首先形成具有弥散边界的无定形离子簇,称之为预成核簇(pre-nucleation clusters,PNC)㊂PNC是热力学稳定的聚集体,可存在于各种不饱和或超饱和溶液中[28]㊂接着,PNC聚集形成无定形矿物前体,在碳酸钙形成过程中的无定形矿化前体为无定形碳酸钙(amorphous calcium carbonate,ACC)[29],在磷酸钙形成过程中的无定形矿化前体为无定形磷酸钙(amorphous calcium phosphate, ACP)[30],继而无定形矿化前体失去结合水,经过固态转化结晶[31]㊂更进一步的研究认为,这种生物矿化过程发生在由特定蛋白质形成的水凝胶环境中,其特有的内部孔隙充当 有限体积的反应容器 ,可以促进无定形矿化前体的形成[32]㊂3.1.2㊀晶体生长晶体生长过程决定了最终晶体的大小和形态㊂和初始矿化相似,晶体生长也可以通过经典结晶理论和非经典结晶理论来解释㊂经典结晶理论认为,在高过饱和溶液中以成核为主,而在低过饱和溶液中晶体生长占主导地位[33]㊂在这一过程中依据的是奥斯瓦尔德现象,即在溶液过饱和的情况下,热力学能量驱动单个原子或分子沉积在成核部位,使材料有序排列生长成稳定的晶体结构㊂溶液中不同的添加剂和物理参数会导致每个单晶面的生长速率不同,从而形成形态各异㊁大小不一的晶体[34]㊂非经典结晶理论认为,矿化前体无定形碳酸钙或无定形磷酸钙通过定向附着形成介晶结构,继而在蛋白质的引导下组装聚集成为晶体结构㊂在此过程中,蛋白质发挥着重要作用㊂例如海胆脊椎基质蛋白SPSM50不仅可增强无定形矿化前体的稳定性,而且以介晶结构的形式诱导了晶体的定向生长[35]㊂3.2㊀细胞内矿化细胞内矿化是指用于细胞内矿化的离子在转运蛋白的作用下被富集至囊泡中,继而发生矿化[36]㊂细胞内矿化与细胞外矿化最大的不同在于有囊泡的参与㊂在此过程中,囊泡膜上的蛋白质以及囊泡内的蛋白质不仅为矿化提供成核位点,也形成了一个 有限体积 以实现蛋白质等分子的集中,称为分子拥挤(molecular crowding)㊂在结晶发生前,一些分子(如聚乙二醇)会抑制矿物前体的形成和自我聚集;在结晶发生时另一些大分子(如牛血清白蛋白)则会促进矿化前体的聚集[37]㊂这一过程也是仿生矿化中的研究热点㊂MTB诱导的铁矿化是细胞内矿化的典型代表㊂其在磁小体内产生纳米级别铁磁性颗粒的可能机制如下(图3)[38]:首先细胞质膜(图3a)内陷形成囊泡(图3b),其次转铁蛋白将铁离子(经细胞)转运到囊泡中㊂包裹Fe2+图3㊀磁小体的形成过程[38]Fig.3㊀The formation process of magnetosomes[38]339博看网 . All Rights Reserved.中国材料进展第40卷的囊泡与细胞骨架接触时,Fe2+氧化成为Fe3+,膜上的蛋白质启动成核,并且调控囊泡内矿化形成磁铁矿晶体(图3c),称之为磁小体㊂磁小体膜上的蛋白质可与肌动蛋白相互作用,使磁小体成链状排列(图3d)㊂随后,在细胞分裂过程中细胞壁通过弯曲磁小体链减少磁力,促进磁小体均匀地分离到子细胞中(图3e和3f)㊂研究表明,MTB基因组上有一段特殊的区域,称为磁小体岛(图3g),该基因岛与磁小体的形成密切相关㊂相关基因如mms及mam家族可调控铁磁性颗粒的形状和大小[39]㊂另有研究发现,磁小体内铁磁性颗粒的形态可能与MTB 的来源有一定的关联㊂例如来自α-蛋白菌和γ-蛋白菌菌属的MTB常产生各向同性生长的八面体棱柱形的铁磁矿,而硝化螺菌菌属的MTB常产生各向异性生长的子弹型铁磁矿[40]㊂4㊀细菌介导生物矿化的应用4.1㊀环境应用随着工业化的快速发展,大量的有毒金属及放射性核素被排放至环境中,对人类健康造成了极大的威胁㊂如何快速有效地回收环境中的污染物是学者们亟需解决的问题㊂随着细菌介导矿化研究的进一步深入,有学者提出可通过耐重金属细菌诱导有毒金属矿化来回收环境中的锶㊁镍㊁铬㊁铅㊁铀㊁镉等有毒金属,改善环境质量[41]㊂虽然高浓度的金属离子可导致多数细菌核酸紊乱及渗透压失衡,但对于这些损伤,细菌已进化出了精妙的抗重金属机制,如金属离子的跨膜运输㊁形成胞内外沉淀㊁与胞内金属硫蛋白的螯合作用等均可将有毒金属离子转化为无毒或毒性较小的物质(图4)[42]㊂由于细菌的大部分抗重金属基因位于质粒上,因此可通过基因操作得到基因编辑细菌,从而用于生物修复[43]㊂例如,研究发现趋磁细菌UPB-MAG05菌株对重金属镉具有高度耐受性,可介导污染水源中镉的矿化沉积,继而在外界磁场的作用下通过磁分离去除,从而净化水质[44]㊂磷酸盐增溶芽孢杆菌可分解含磷酸盐的有机化合物,在其细胞表面产生磷酸盐基团,并与铅离子沉淀为稳定的Pb3(PO4)2,从而达到清除铅离子的目的[45]㊂相较于传统的物理化学修复方法,通过细菌矿化重金属修复污染环境的方法具有成本低廉㊁后期处理简单等优点,但细菌矿化重金属的长期有效性尚未得到证明,已经结合的重金属在环境变化的条件下可能重新活化,回到环境中㊂图4㊀细菌抗多种有毒金属的机制[42]Fig.4㊀The mechanism of bacterial resistance to toxic metals[42]4.2㊀工业应用细菌介导的矿化也可以用于电化学领域的能源存储㊂研究发现铁氧化细菌Acidovorax可介导γ-FeOOH发生矿化,形成保留细菌大小和形状的α-Fe2O3纳米晶体㊂α-Fe2O3纳米晶体组装形成中空多孔的壳,导电性强,在与锂反应时有更强的电化学可逆性㊂此种生成纳米晶体的方法不仅具有生态友好性,也可实现工业上的规模化生产[46]㊂由电化学活性细菌Shewanella oneidensis介导合成的高度分散的钯金合金纳米粒子可用作液体燃料电池的电催化剂[47]㊂研究发现,通过基因技术使大肠杆菌表面表达硅藻silaffin蛋白的重复片段,其调控合成的纳米二氧化钛锐钛矿具有出色的锂储存性能,可用作锂离子电池的阳极[48]㊂混凝土是目前广泛使用的建筑材料,但随着时间的流逝,混凝土内部产生的裂缝会降低建筑结构的机械性能,缩短建筑物使用年限㊂有研究提出可在混凝土中加入能够介导碳酸盐沉淀的细菌,其产生的碳酸钙可增强混凝土对氯离子和渗透水的抵抗力,提高混凝土耐久性439博看网 . All Rights Reserved.㊀第11期王婉蓉等:细菌介导生物矿化的研究进展和强度;同时碳酸钙可填补裂缝,形成自修复混凝土,增加建筑的使用寿命(图5)[49]㊂研究证实,当初始裂缝宽度不大于0.5mm 时,使用自修复混凝土时大部分裂缝可完全愈合[47]㊂但由于混凝土由硅酸盐水泥制成,水化后可产生氢氧化钙,使混凝土呈强碱性,且混凝土基质中的孔隙尺寸小于1μm,而细菌的大小为1~4μm,这些条件都不利于细菌存活[50]㊂因此如何提高细菌在混凝土基质中的生存能力是目前的研究热点㊂有学者提出可使用微胶囊技术来保护细菌,使细菌在合适的环境下介导碳酸盐沉淀[51]㊂图5㊀通过细菌诱导碳酸钙沉淀修复混凝土开裂的示意图[49]Fig.5㊀Schematic of bacteria induced calcium carbonate precipitation to repair concrete cracking [49]4.3㊀生物医学应用4.3.1㊀医疗成像设备和诊断磁共振成像(magnetic resonance imaging,MRI)技术由于具有良好的空间分辨率和软组织对比度,是临床上常用的影像检查手段之一㊂研究发现MTB 产生的磁性纳米颗粒具有较强磁性,可作为造影剂增强组织中质子共振吸收,使局部组织图像得到增强,从而提高检查的灵敏度和特异性[52]㊂除增强成像对比度之外,功能化的磁性纳米颗粒芯片还可用于食源性病原物的检测,如大肠杆菌㊁霍乱弧菌㊁空肠弯曲菌㊁金黄色葡萄球菌等[53]㊂如图6所示,趋磁细菌MO-1功能化之后可与金黄色葡萄球菌表面的A 蛋白结合,从而实现靶向功能[54]㊂目前可以通过化学修饰和基因工程的方法生产功能化磁小体㊂化学修饰作用于磁小体中的Mam㊁Mms 等蛋白上,有以下结合方式:①通过磁小体膜上的氨基或羧基进行功能化修饰,例如经肽P75修饰的磁小体可与人表皮生长因子受体和上皮生长因子受体2结合[55];②使用葡萄球菌蛋白A 用作融合标签,葡萄球菌蛋白A 作为一种免疫球蛋白G 结合蛋白,可与MamC㊁MamF 以及免疫球蛋白Fc 区结合,从而介导磁小体-葡萄球菌蛋白A 复合物与抗体结合[56];③利用磁小体膜上的 NH 2基团与抗体的 NH 2或 SH 基团之间的反应进行化学修饰;④用生物素/链霉亲和素进行修饰;⑤利用正负电荷之间的相互作用进行修饰,磁小体膜上的磷脂带有负电荷,可与带正电荷的抗癌重组质粒热激蛋白㊁70-polo 样激酶1短发夹RNA 以及阿霉素结合[57]㊂另外还可通过基因工程改造对磁小体进行功能化修图6㊀趋磁细菌靶向金黄色葡萄球菌的微机器人系统的构建[54]Fig.6㊀Construction of a microrobot system using magnetotactic bacteria for targeting Staphylococcus aureus [54]539博看网 . All Rights Reserved.中国材料进展第40卷饰㊂将表达功能蛋白的基因与mms16,mam13等膜蛋白基因融合,再将融合基因转移到MTB中,从而可实现目标蛋白的表达㊂例如,将磁小体和翡翠绿色荧光蛋白(EmGFP)或生物素修饰的烟草花叶病毒(tobacco mosaic virus,TMV)共同培养,可生成表达这些蛋白的磁性纳米链[58]㊂由于化学修饰可能引入有毒物质,且在MTB中引入外来活性蛋白质的基因的操作比较复杂,因此最近的研究中提出了一种新的修饰方法㊂首先通过基因技术在大肠肝菌中表达与磁小体MamC蛋白融合的抗人表皮生长因子受体2(human epidermal growth factor receptor-2, HER2),然后去除磁小体膜中的磷脂双层中的膜蛋白,以利于从大肠肝菌中提取的基因工程产物抗HER2与磁小体上的MamC蛋白结合,从而实现HER2阳性乳腺癌在磁共振成像中的检测[59]㊂这种技术有望成为无创检测肿瘤的手段,具有较大的临床应用价值㊂4.3.2㊀抗肿瘤方法高温疗法可通过多种机制作用于癌细胞上使其变性坏死,但目前该疗法缺乏特异性,难以区分健康细胞与癌细胞㊂遂有研究提出 生物靶向磁性热疗 的概念,意为在外源交变磁场的作用下加热磁性颗粒,由于磁滞损耗或松弛损耗产生不同程度的升温现象,可在磁性颗粒聚集的地方选择性地抑制癌细胞增殖[60]㊂由MTB产生的磁小体由于磁性较强,可在交变磁场中产生较大的热量;同时由于磁小体呈链状排列,不易聚集,可使肿瘤细胞均匀升温,有效抑制其增殖[61],因此磁小体在磁热疗领域有较大的应用前景㊂研究表明,聚赖氨酸包裹的磁小体具有更好的生物相容性,在胶质母细胞瘤小鼠模型的实验性磁热疗中,可显著抑制肿瘤细胞的生长[6]㊂但是到目前为止,多数关于磁小体抗肿瘤治疗的研究都是使用肿瘤细胞株进行实验的,未进行动物实验研究或人类临床试验,因此磁小体的临床抗肿瘤能力还需进一步验证㊂4.3.3㊀药物输送系统靶向给药是指将药物选择性地传输定位于病变位置,从而发挥药理作用的给药方式㊂在肿瘤微环境中,由于细胞的大量增殖消耗氧气,肿瘤组织周围氧气缺乏㊂目前使用的纳米药物载体,如脂质体㊁胶束㊁聚合物纳米颗粒难以到达缺氧区域,靶向率低㊂而MTB适合厌氧生长,故目前有研究通过MTB和磁小体构建纳米机器人,在外磁场的作用下,纳米机器人可聚集于病变部位,提高病变部位的药物浓度,改善治疗效果[62]㊂例如,将载有药物的纳米脂质体交联至海洋趋磁细菌MC-1表面,并将其注射到实验小鼠的肿瘤组织周围,在外磁场的作用下,有高达55%的MC-1细胞渗透到肿瘤缺氧区[63]㊂5㊀结㊀语综上所述,相比于物理和化学合成方法,细菌介导生成的矿物在环境㊁工业及生物医学领域均发挥着重要的作用㊂虽然目前对细菌介导的生物矿化的研究已经取得部分进展,但仍有许多关键的科学问题亟待解决㊂由于多数细菌介导矿物生成的实验室培养条件并不适宜工业化生产,所以如何将实验室阶段的科学成果转化为可规模化生产的具体技术是限制其应用的关键瓶颈㊂其次,虽然纳米机器人在肿瘤治疗领域有较大的应用前景,但人体免疫系统对其会有如何反应目前尚不完全清楚[64]㊂为了实现细菌介导生物矿化的大规模应用,还需进一步地研究以解决上述问题㊂参考文献㊀References[1]㊀ALSENZ H,ILLNER P,ASHCKENAZI-POLIVODA S,et al.Geo-chemical Transactions[J],2015,16(1):2.[2]㊀DHAMI N K,REDDY M S,MUKHERJEE A.Frontiers in Microbiolo-gy[J],2014,5:304.[3]㊀PERRY R S,MCLOUGHLIN N,LYNNE B Y,et al.Sedimentary Ge-ology[J],2007,201(1/2):157-179.[4]㊀PETERS S E,GAINES R R.Nature[J],2012,484(7394):363-366.[5]㊀SCHWADERER A L,WOLFE A J.Annals of Translational Medicine[J],2017,5(2):32-37.[6]㊀LE FÈVRE R,DURAND-DUBIEF M,CHEBBI I,et al.Theranostics[J],2017,7(18):4618-4631.[7]㊀LOHßE A,KOLINKO I,RASCHDORF O,et al.Applied and Envi-ronmental Microbiology[J],2016,82(10):3032-3041. [8]㊀AL DISI Z A,JAOUA S,BONTOGNALI T R,et al.Frontiers in En-vironmental Science[J],2017,5:1.[9]㊀BENTOV S,ABEHSERA S,SAGI A.The Mineralized Exoskeletons ofCrustaceans[M]//COHEN E,MOUSSIAN B.Extracellular Composite Matrices in Arthropods.Cham:Springer International Publishing, 2016:137-163.[10]VITTORI M,ŽNIDARŠI N,ŽAGAR K,et al.Journal of Structural Biology[J],2012,180(1):216-225.[11]URIZ M J,AGELL G,BLANQUER A,et al.Evolution[J],2012,66(10):2993-2999.[12]MYKYTCZUK N,LAWRENCE J R,OMELON C R,et al.Polar Biol-ogy[J],2016,39(4):701-712.[13]SAURO F,CAPPELLETTI M,GHEZZI D,et al.Scientific Reports[J],2018,8(1):17569.[14]KREMER B,KAZMIERCZAK J,LUKOMSKA-KOWALCZYK M,etal.Astrobiology[J],2012,12(6):535-548.[15]CHEN Y R,ZHANG W Y,ZHOU K,et al.Environmental Microbiol-ogy Reports[J],2016,8(2):218-226.639博看网 . All Rights Reserved.。

巨菌草根部促生菌的筛选及其促生效应作者：邓振山陈凯凯李静刘显春张宝宝张宝成来源：《广西植物》2020年第09期摘要：为进一步开发植物促生菌，该研究以巨菌草根部为主要材料进行巨菌草促生菌的筛选，采用解磷、固氮和产IAA等筛选标准对初筛菌株分别进行多项促生能力的测定。

通过形态观察、生理生化特性和 16S rDNA序列同源性分析对促生效果最好的菌株YB-07进行分类和鉴定，分别测定其促生能力后从中筛选出促生效应强的11个菌株进行盆栽试验，并通过对这些菌株单独回接和多菌混接的小麦盆栽试验测定其对小麦的促生效应。

结果表明：从巨菌草根部分离得到了101株促生菌株，分类鉴定结果显示菌株YB-07归属于根瘤菌属（Rhizobium），其溶磷量为20.1 mg·L-1、产IAA量为23.7 mg·L-1，同时具有产氨能力。

盆栽试验测定结果显示，多菌混合接种对小麦的促生效应在株高、干重、鲜重和叶绿素含量上，分别较对照组增加了24.49%、31.84%、28.06%和34.14%。

单菌接种对小麦的促生表现在株高、干重、鲜重和叶绿素含量上，分别较对照组增加了13.54%、20.45%、16.84%和35.19%。

所筛选到的菌株具有良好的促生长作用，能为进一步构建巨菌草促生菌菌群提供良好的种质资源。

关键词：巨菌草，促生菌，筛选，促生效应，盆栽试验中图分类号：Q939.95文献标识码：A文章编号：1000-3142（2020）09-1323-09Abstract：In this study，the root of the Pennisetum sinese was used as the main research material，screening of growth-promoting strains from P. sinese，and explore the growth-promoting effects of growth-promoting strains. We used the following screening criteria for the determination of multiple growth-promoting capacities of primary strains：the ability to solubilize phosphorus，the ability to fix nitrogen，the ability to produce IAA. The strain YB-07 with the best growth-promoting effect was classified and identified through physiological and biochemical characteristics and 16S rDNA sequence homology analysis. Eleven strains with better overall performance were screened out and used for a pot experiment with a single inoculation and multi-microbe mixed inoculation to determine its growth-promoting effect. A total of 101 strains were isolated from the roots of the P. sinese，and the growth-promoting ability was measured. Among them，the strain with excellent overall performance was YB-07，which had a phosphorus content of 20.1 mg·L-1，an IAA yield of 23.7mg·L-1，and an ability to produce ammonia at the same time. The results of pot experiment showed that the effect of multi-microbe mixed inoculation on wheat growth increased by 24.49%，31.84%，28.06% and 34.14% in the height，dry weight，fresh weight and chlorophyll content，respectively. Single bacterium inoculation increased the plant height，dry weight，fresh weight，and chlorophyll content by 13.54%，20.45%，16.84% and 35.19%，respectively，compared with the control group. The selected strain has good growth-promoting effect，can provide a good seed resources for the further construction of the P. sinese flora promoting bacteria.Key words：Pennisetum sinese，promoting bacteria，screening，growth-promoting effect，pot experiment巨菌草（Pennisetum sinese）隸属于禾本科狼尾草属，多年生，适宜在热带、亚热带、温带生长和人工栽培。

第34卷第1期 海南师范大学学报（自然科学版）V〇l.34N〇.l 2021 年3 月Journal of Hainan Normal University(Natural Science)Mar.2021Doi ： 10.12051/j.issn. 1674-4942.2021.01.010黑木耳黑色素的研究综述陈雅，徐苗，王欣宜，单欣荷，季琳凯，张拥军*(中国计量大学生命科学学院，浙江杭州310018)摘要：黑木耳是中国一种分布极为广泛且具有独特的营养价值与保健功能的食用菌，含有多 种生物活性化合物，其中黑色素是主要生物活性成分之一，且具有极高的安全性，可进一步开发具 备保健作用的功能色素，该方面的研究已初见成效且应用前景广阔。

文章综述了黑木耳黑色素的 理化性质、分子组成与结构表征、分离制备手段以及其清除自由基、抑菌抗病毒、抗辐射、改善肝损 伤、保护D N A等生物活性的国内外研究现状，分析了限制黑木耳黑色素开发应用的实际问题并提 出展望，并为今后黑木耳黑色素生物活性作用机制的研究及其在食品、药品、化妆品等领域的应用 提供参考。

关键词：黑木耳；黑色素；分离提取；生物合成；分子结构；生物活性中图分类号:0629.1 文献标志码:A文章编号：1674-4942(2021)01-0063-07Summary of Melanin of A u ricu la ria au ricu laCHEN Ya, XU Miao, WANG Xinyi, SHAN Xinhe, Jl Linkai, ZHANG Yongjun' (College of L ife Science,China Jiliang University,Hangzhou 310018, China) Abstract：Auricularia auricula is an edible fungus with a unique nutritional value and healthy function and is widely dis­tributed in China. It contains a variety of bioactive compounds. Melanin is one of the main bioactive components with high safety. It can be further developed into func tional pigments with health care function. The research in this field has broad application prospects. In this paper, the physicochemical properties, molecular composition, structural characterization, sep­aration and prej)aration methods of Auricularia auricula melanin, as well as its biological activities such as scavenging free radicals, antibacterial and antiviral, antiradiation, improving liver injury, protecting DNA and so on, were reviewed. The problems limiting the development and application of Auricularia auricula melanin were analyzed, and the prospects were put forward, which would be helpful for the study of the biological mechanism of Auricularia auricula melanin and its appli­cation in food, medicine, cosmetics and other fields.K ey w〇r d s：/lz/m*z//rtrirt ai/rzcw/a;melanin;separation and extraction;biosynthesis;molecular stnicture;biological activity黑木耳(4w r/c a/a r i Y/aur/cu/fl)隶属担子菌亚门（Basi(liomycotina)层菌纲（Hymenomycetes)木耳目（Auricu- I a r i a les)木耳科(A u r i c u1a riaceae)木耳属(yWfcw/rmVz )，为中国珍贵的药用和食用菌，早在19世纪，黑木耳就被 用于民间医药，用于治疗咽喉痛、眼痛、黄疸等病症，并作为收敛剂"_21。

【大二篇】学术英语总结（考试形式）医学英语总结一．考试形式：1.词→词根/词缀（10×1'）PS：课文后面的Part IV部分大家要好好看一看和背一背啊。

2.词组翻译：汉→英句子翻译：英→汉（共50'左右）3.段落翻译（25'）PS：基本都是文章中的，大家要注意老师上课说过的句子。

4.医学科普论文阅读2篇，一篇5道选择题。

（10×1.5'）5.最重要的是，没有作文！O(∩_∩)O~~二．各单元总结（单词肯定要大家自己背啦，我就不啰嗦了）UNIT 1.1.词（老师上课补充的）：inter-之间的interlobar叶间的；interlobular小叶间的；intersegmental节间的；intercurrent间发的；intercostal肋间的2.词组：capillarynetwork：毛细血管网；majorcalyx：肾大盏；minorcalyx：肾小盏；bronchialcirculation:支气管循环；draininto：消耗，流进；bepositioned in:居于，位于；extendinto：向…延伸；becomposed of：由…组成；coronaryartery disease:冠状动脉疾病；3.句子：（只是上课老师重点提过的句子，基本上是主课文中的，大家多注意下，还有各章中Part VI的translation，也要关注一下。

）(1)Thenutritive blood flow to all but the alveolar structures comes from thebronchialcirculation,which originates from the aorta and upper intercostalarteries and receives about 1 percent of cardiac output.(P2第一段第二句）它的营养血液来自于支气管循环系统，流向肺部除肺泡外的所有组织，因为支气管循环系统始于主动脉及上肋间动脉，接受大约1%的心输出量。

Unit1肺和肾的功能肺的血管系统肺从两个血管系统----支气管循环系统和肺循环系统获得血液供应;它的营养血液来自于支气管循环系统,流向肺部除肺泡外的所有组织,因为支气管循环系统始于主动脉及上肋间动脉,接受大约1%的心输出量;大约三分之一的支气管循环的静脉输出流入全身静脉,然后回到右心房;剩余的输出流入肺静脉,并在心脏最小静脉的作用下,在正常情况下,以1%-2%的量自右向左分流;肺动脉系统沿着气道从肺门向外周延伸,向下连接下段气道直径大约2毫米的动脉,它们壁薄且富有弹性;从这儿开始,动脉成肌肉化发展,直至其达到30微米,此时肌层消失;因为这些小肌肉动脉起着积极控制肺部血流分布的作用,所以大部分动脉压降产生在这些小肌肉动脉中;肺小动脉将血液排空,送入广泛分布的毛细血管网,进入肺静脉;肺静脉的壁很薄,它们最终在肺门处与动脉和支气管汇合,出肺进入左心房;肾结构成分人类肾脏在解剖学上位于腹膜后隙,与下胸椎和上腰椎平行;每个成年人的肾脏大约重150克,长、宽、厚分别为12厘米、6厘米以及3厘米;肾脏的冠状部分分为/由两个明确的区域组成;外周部的皮质大约1厘米厚,深部的髓质由几个肾锥体构成;这些锥体状结构的底部位于皮髓质结合处;锥体的顶部伸入肾门,称为肾;每个肾被一个肾小盏包裹;肾小盏与肾大盏相聚组成肾盂;经肾流出的尿液汇集在肾盂,通过输尿管排入膀胱;由主动脉分支出来的肾总动脉为两肾输送血液;肾总动脉通常分为两个主侧支,这两个侧支又进一步分为叶动脉,为肾脏上、中、下区域供应血液;当这些血管进入肾实质,变成叶间动脉通向肾皮质时,这些血管又进一步细分;细分后的更小血管在皮髓质结合处成为竖支--弓状动脉;从弓状动脉伸出的叶间动脉进入皮质;由于传入小动脉始于这些末端叶间动脉,所以为肾小球毛细血管输送血液;组织学上,肾脏是由一个叫做“肾单位”的基本单位组成;每个肾脏约含有一百万个肾单位,“肾单位”有两个主要成分：过滤成分―紧包着毛细血管网肾小球和一个附着在上面的小管组成;这个小管包含几个明显的解剖和功能成分;Unit2细胞与衰老衰老是一种正常的生理过程,伴有肌体内平衡适应性反应的进行性改变;研究老年人健康问题和保健的特殊分支称作老年医学;衰老的明显特征众所周知：头发花白和脱落,牙齿脱落,皮肤起皱,肌肉减少,脂肪积存增加;衰老的生理征兆是肌体对环境压力反应的功能和能力逐渐减退.;如同保持不断地体内平衡应对温度、饮食和氧供反应变慢一样,机体代谢也减慢了;衰老的这些迹象与机体中细胞数的净减少及存余细胞的功能缺失有关;衰老的另一个表现是组织的细胞外成分也随年龄的变化而变化;负责肌腱力量的胶原纤维的数量增加,而质量却随着衰老降低;动脉壁胶原质中的变化造成动脉壁伸展性缺失,如同动脉壁上的积聚物造成动脉粥样硬化即动脉壁脂肪物质堆积一样;弹性蛋白是另一种细胞外成分,主要负责血管和皮肤的弹性;随着年龄的变化,它的变粗,变碎并需要获得更大的钙亲和力,这些可能也是造成动脉粥样硬化的原因;葡萄糖在机体中是最丰富的糖类,它在衰老的过程中也可能起作用;根据一个假设,任意给细胞内外的蛋白质增加葡萄糖,结果会在相邻蛋白质分子间形成不可逆交联;当人衰老时,会形成更多的交联,这可能导致正在衰老的组织变得僵化,丧失弹性;虽然正常情况下,每分钟会有好几百万的新细胞产生,但人体有几种细胞：心脏细胞,骨骼肌纤维细胞,神经细胞是无法替代的;实验显示,许多种类的细胞分裂能力有限;在机体外生长的细胞仅仅分裂几次就停止了;细胞分裂数与捐献者的年龄有关,与这些细胞获取的不同物种的正常寿命有关;这些发现为这种假说提供了有力证据,即细胞有丝分裂的终止是正常的,有基因决定的;根据这个观点,衰老基因是出生时就存在的基因蓝图的一部分,它取决于生命攸关的减慢或停止过程出现的特定时间;衰老的另一个理论即自由基理论;自由基是含有未配对电子的带电荷分子;这是一种不稳定的高反应性分子,容易损害蛋白质;自由基的影响有：皮肤起皱,关节僵直,动脉硬化;自由基也可以损害ＤＮＡ;造成自由基的因素有：空气污染,放射线以及我们摄取的某些食物;饮食中的其他物质如维生素Ｅ,维生素Ｃ,β－胡萝卜素以及硒都是抗氧化剂,可以抑制自由基形成;最近的两个研究支持了衰老的自由基理论;孕育健康长寿的果蝇株产生超正常量的酶：过氧歧化酶;它可以中和自由基;同样,把产生过氧歧化酶的基因注射进果蝇胚胎会延长其平均寿命;然而,关于衰老的理论,有些是在细胞水平上解释其过程,有的则强调整个生物体内运作的调节机制,比如免疫系统产生各种抗异物侵扰的抗体,可是会对细胞本身发起攻击;这种自身免疫应答可能是细胞表面变化造成,引起抗体附加并标记出破坏细胞;当细胞表面变化增加,自身免疫应答加强,产生众所周知的衰老;Unit3生物化学和人类发展生物化学是在细胞和分子水平上运用化学研究生物过程的学科;省略2句生物化学使用化学、物理学、分子生物学和免疫学研究在生物物质中发现的复杂分子的结构与行为,研究那些分子相互作用构成细胞、组织和整个生物体的方式;生物学涉及从基因移植到巨分子结构和功能的广阔的细胞功能范围;……比如：单分子DNA如何复制生成其本身两个完全相同的副本,DNA分子中基础序列如何确定编码蛋白质中氨基酸的序列;我们以详细的机械术语描述这些生物进程的能力为其他生物科学研究奠定了坚实的化学基础;再者,我们把基础生命过程理解为化学结构和反应,比如遗传信息的传输,这种意识具有重要的哲学含义;……第二,……导致镰状细胞贫血、囊性纤维化、血友病和许多其他遗传疾病的分子病变在生物化学的水平上得以阐述;一些导致癌症发生的分子事物得以识别;了解基本的缺陷为发现有效的治疗方法开启了大门;生物化学使得合理设计新药成为可能,包括病毒如HIV病毒复制所需的酶的特殊抑制剂;生物工程制造的细菌或其他生物可以用来作为制造有价值蛋白质的工厂,如胰岛素和血细胞发育的诱导剂;生物化学非常有助于临床诊断;……DNAprobesDNA探针在遗传疾病,传染性疾病以及癌症的精确诊断中越来越起作用;农业也应生物化学的发展受益匪浅,产生了更加有效的、对环境无害的除草剂、杀虫剂;基因工程植物更能抵抗虫害;所有这些努力因基因组测序的进展而加速发展;第三,生物化学的进展正在使研究者们研究一些生物和医学上最令人激动得问题;受精卵如何会产生与肌肉、大脑和肝脏细胞不同的细胞感官是如何工作的大脑疾病如老年痴呆症和精神分裂症的分子基础是什么免疫系统如何区分自我和非自我长期记忆和短期记忆的分子机制是什么对于这些问题的答案,过去曾经似乎很遥远,现在已经得到初步解答,并且可能在不久的将来得到更加全面的解答;Unit4病理学简介病理学是研究疾病的科学;在临床实践和医学教学中,病理学的含义更为广泛：病理学由一系列的知识、观点和研究方法构成,它们对理解现代医学及医学实践至关重要;病理学不等同于疾病组织的形态学,把两者等同起来是一种过时的看法;病理学包括对疾病功能及结构的认识和理解,包含从分子水平到对个体的影响;随着新科学方法的应用,人们更深入地了解疾病,病理学所涵盖的内容也会不断地改变、更新和拓展;病理学的最终目的在于确定疾病的原因,从而达到防治疾病的基本目标;病理学的范围病理学是医学科学和实践的基础;没有病理学,医学实践也将无从谈起;临床病理学和实验病理学人们对疾病的认识来自于对病人的观察,同样也来自于对动物和细胞培养的实验性研究;而最大的贡献则来自于对病体组织和体液的深入研究;临床病理学临床医学以对疾病的纵向研究为基础,即研究病人病史,检查、研究和治疗疾病;而临床病理学更关注疾病本身的现况分析,深层次研究发病原因和机制,以及疾病对人体各个器官和系统的影响;两者相辅相成、不可分割;不理解病理学,临床医学无从开展；而没有了临床意义,病理学也就失去了存在价值;实验病理学实验病理学观察诸如疾病动物模型或细胞培养等实验系统的操作效果;幸运的是,细胞培养技术在进步,所以在医学研究和实验病理学中,人们对实验动物的使用减少了;然而,通过细胞培养复制完整人体中普遍存在的生理环境仍然是一种极其困难的尝试;病理学的分支病理学是一门拥有庞大分支的学科;在实践中,病理学包含以下几大分支：组织病理学：通过对组织的检查研究和诊断疾病;细胞病理学：通过对单个细胞的检查研究和诊断疾病;血液病学：对血液中细胞成分和可凝结成分的异常进行研究;微生物学：对传染性疾病及相关生物体进行研究;免疫学：对机体特殊防御机制进行研究;病理化学：从组织和体液的变化中研究和诊断疾病;遗传学：对异常染色体和基因进行研究;毒理学：对已知或疑似毒物的作用进行研究;法医病理学：病理学在法律中的应用,比如对可疑情况下的死亡进行调查;由于这些分支都拥有各自的专业人士队伍,对病理学进行划分的专业意义大于它的教育意义;病理学的教学必须着眼于整体,因为在这些常规分类中机体和疾病是没有区分的;因此,该书采用多学科方法阐述病理学;系统病理学部分概述各器官的正常结构与功能,描述各临床症状和体征的病理学基础,强调了各疾病的临床意义;普通病理学和系统病理学病理学教学内容分为两部分：普通病理学：研究和阐明主要疾病过程的机制和特点,如先天性疾病和后天性疾病、炎症、肿瘤和恶化等;系统病理学：描述影响各器官或器官系统的各种疾病,如阑尾炎、肺癌和动脉粥样化等;普通病理学普通病理学总论研究和阐明存在于各主要疾病的共同病因、发病机制和特点;本书第二部分包含这些内容,举例说明各种疾病;在学习系统病理学之前,理解普通病理学的各原理至关重要;普通病理学是学习各种疾病系统病理学之前所必须具备的理论基础;系统病理学系统病理学各论研究和阐明影响各器官或器官系统的各种疾病;注意区分“系统的”和“人体的”在本文中的使用;人体病理学具有遍及所有人体系统的疾病的特性每种疾病通常是由于普通病理学中最具特征的一类或更多种类的原因和发病机制造成;因此,急性阑尾炎是影响阑尾的急性炎症；肺癌是肺细胞受到致癌作用的结果；而因此形成的癌细胞的行为会遵循已确立的恶性肿瘤的模式,等等;unit5Innate immunity also called natural or native immunity provides the early line of defense against microbes. it consists of cellular and biochemical defense mechanisms that are in place even before infection and are poised to respond rapidly to infections .These mechanisms react to microbes and to the products of injured cells . and they respond in essentially the same way to repeated infections .The principal components of innate immunity are 1 physical and chemical barriers. such as epithelia and antimicrobial chemicals Produced at epithelial surfaces: 2 phagocytic cells neutrophils, macrophages , dendritic cells. and natural killer NK cells: 3 blood proteins, including members of the complement system and other mediators of inflammation; and 4 proteins called cytokines that regulate and coordinate many of the activities of the cells of innate immunity. The mechanisms of innate immunity are specific for structures that are common to groups of related microbes and may not ,distinguish fine differences between microbes. 固有免疫又叫自然免疫或者先天性免疫为抵制微生物提供了早期的天然防线;它有细胞和生化机制构成,他们甚至在感染之前就已经开始运转,随时准备迅速应对感染;这些机制对微生物和受损细胞的产生做出反应,也已基本相同的方式应对重复感染;固有免疫主要成分是1.物理和化学屏障,比如上皮组织和上皮表层产生的抗菌化学物;2.噬菌细胞嗜中性粒细胞,巨噬细胞,树突状细胞和自然杀伤细胞;3.血蛋白,包括补体系统的成分和其他的炎症介质;4.一种叫做细胞因子的蛋白质能够调节和协调固有免疫的细胞活动;固有免疫机制是专门针对成组的相关联微生物共同拥有的结构的,他们可能无法分辨为生物之间的细小差别; In contrast to innate immunity. there are other immune responses that stimulated by exposureto infectious agents and increase in magnitude and defensive capabilities with each successive exposure to a particular microbe Because this form of immunity develops as a response to infection and adapts to the infection. it is called adaptive immunity. The defining characteristics of adaptive immunity are exquisite specificity for distinct molecules and an ability to "remember" and respond more vigorously to repeated exposuresto the same microbe .The adaptive immune system is able lo recognize and react to a large number of microbial and nonmicrobial substances. In addition. it has an extraordinary capacity to distinguish between different , even closely related, microbes and molecules,and for this reason it IS also called specific immunity. It is also sometimes called acquired immunity. to emphasize that potent protective responses are “acquired" by experience .Themain components of adaptive immunity are cells called lymphocytes and their secreted products.such as antibodies. Foreign substances that induce specific immune responses or are recognized by Symphocytes or antibodies are called antigens. 与固有免疫相比,因接触感染因子而被激活的其它的免疫反应会因为与某一种微生物的反复接触而体积增大和防御能力增强;因为这种形式的免疫会随着对感染的反应而发展和调整,因此叫做适应性反应;适应性免疫的明确特征是对不同的分子有敏锐的特异性,他有记忆的功能能够对相同微生物的重复感染做出更加激烈的应答;适应性免疫系统能够识别,并对大量的微生物和非微生物产生应答;此外,他有一种卓越的能力,能够区别不同的甚至是关系紧密的微生物和分子;正因为如此,它有被成为特异性免疫,有时候也叫后天免疫,是为了强调这种强大的保护应答是因为不断接触而获得的;适应性免疫的主要成分是淋巴细胞和他们的分泌物比如抗体;诱发特异性免疫或者被淋巴细胞或抗体识别的外来物质被称为抗原; Mechanisms for defending the host against microbes are present in some form in all multicellular organisms . These mechanisms constitute innate immunity The more specialized defense mechanisms that constitute adaptive immunity are found in vertebrates only. Two functionally similar but molecularly distinct adaptive immune systems developed at differenttimes in evolution. About 500 million years ago, jawless fish. such as lampreys and hagfish. developed a unique immune system containing diverse lymphocyte-like cells that may functionlike lymphocytes in more advanced species and even responded to immunization The antigen receptors on these cells were variable leucine-rich receptors that were capable of recognizing many antigens but were distinct from the antibodies and T cell receptors appearedlater in evolution. Most of the components of the adaptive immune system, including lymphocytes with highly diverse antigen receptors, antibodies. specialized lymphoid tissues, evolved coordinately within a short time in jawed vertebrates e. g. , sharks. about 360 million years ago. The immune system has become increasingly specialized with evolution . 保护诉诸抵制微生物的机制在所有的多细胞生物中以某种形式存在着;这些机制构成了固有免疫;构成适应性免疫的更加特异的防御机制只有在脊椎动物身上才有;在进化过程中两种功能相似但是分子相异的适应性免疫系统在不同时期得到了发展;大约5亿年前,八目鳗和盲鳗这些无颚鱼进化了一种独一无二的免疫系统,它有各种像淋巴细胞一样的细胞,能在更加高级的物种里像淋巴细胞一样发挥作用,甚至能对免疫应答;这些细胞上的抗原受体是多变的亮氨酸受体,能够识别许多的抗原,但是却和后来进化过程中出现的抗体和T细胞不同;适应性免疫系统的大多数成分,包括带有高度多样化抗原受体的淋巴细胞,抗体和特异的淋巴组织,是在3亿6千万年前在有颚脊椎动物比如鲨鱼中短时间里协调进化的;免疫系统也在进化过程中日益特异化; Innate and adaptive immune responsesare components of an integrated system of host defense in which numerous cells and moleculesfunction cooperatively. The mechanisms of innate immunity provide effective initial defense against infections. However. many pathogenic microbes have evolved to resist innate immunity. their elimination requires the more powerful mechanisms of adaptive immunity .There are many connections between the Innate and adaptive immune systems. The innate immune response to microbes stimulates adaptive immune responses and influence nature of the adaptive responses Conversely. adaptive immune responses often work by enhancing the protective mechanisms of innate immunity, making capable of effectively combating pathogenic microbes. 固有免疫和适应性免疫是宿主整个防御系统组成成分,无数的细胞和分子彼此协作;固有免疫的机制对感染提供早期的有效防御,然而,一些病原微生物已经进化到可以抵制固有免疫,消除他们需要更加强大的适应性免疫机制;固有免疫和适应性免疫有千丝万缕的联系,对微生物的固有免疫应答会激发适应性免疫应答,影响适应性免疫的性质;反过来,适应性免疫应答常常通过加强固有免疫的保护机制是自己有能力和病原微生物有效的战斗;unit7受体药理学研究化学物质对生物体形象的方方面面,当其用于缓解或治疗疾病时,称为药物; 大多数药物通过与生物体的受体结合产生药效;药物分子与受体之间的化学键通常可以逆转;药物和受体的反应是否活跃取决于两者三维立体结构互补程度高低;因此,药物化学结构上的微小改变就有可能对药理活性产生深远/很大的影响; 药理是交叉学科,直接从所有基础医学学科吸取知识资源,反之也为临床医学的方方面面提供信息;因此,药理学的中心原理-受体概念的出现应该是源于生物学家john Newport Langley和以研究免疫学和梅毒化学疗法而闻名的大师Paul ehrlich等人的研究倒是合情合理的了; 还在剑桥大学读生理学本科时,langley已发现阿托品可拮抗匹鲁卡品对平滑肌的收缩作用;他于1878年发表研究成果,并假设“神经末梢或腺体细胞存在一种或一类物质,与阿托品、匹鲁卡品都可形成化合物,且化合过程遵循某种法则,两种药物的相对质量、他们与该物质的化合亲和性是影响因素;”之后三十年间,langley脑中逐渐形成这类“物质”特征的更为清晰的图景;通过对失神经肌肉去神经骨骼肌的实验,他得出结论：药物并非直接作用于神经末梢或是肌肉;他观察到无论肌肉是否受神经支配,尼古丁都能引起肌肉收缩,此外,当时普遍认为箭毒作用于神经末梢,langley研究发现箭毒可以阻滞尼古丁对失神经肌肉去神经骨骼肌的收缩作用;最后,被箭毒麻痹的肌肉受到电击仍会收缩;Langley认定尼古丁和箭毒一定是与神经/肌肉以外的某种物质结合,1905年他将该物质命名为“接受物质”; 1878年enrlich的医学博士毕业论文标题为某些重要染料的组织学功能;惊叹于用于组织染色的某些染料呈现出特异性,他推测药物是否产生治疗效果取决于它是否具有“合适的亲和性”;然而,他将这个想法最先应用于免疫学而非药理学;根据他的侧链理论：通过特殊化学功能组,毒素与抗毒素可形成联合;之后,他扩展理论引入新概念：寄生虫体内的化学受体,这些受体可作为神奇的化学子弹药物瞄准的靶点;尽管这些观点完全受到现代药理学家的认可,erhlich很长时间却一直反对用来解释药物-组织的相互关系,因为从呻毒与锥虫的牢固结合有较强疗效到许多药物的药效之短暂之间存在认识上的巨大鸿沟;但是随着时间的流逝、数据的积累、特别是langley实验的启发,ehrlich最终“打消疑虑,接受了化学受体的概念”; 如今,受体理论成为理解化学物质对生物体作用的通用概念,无论该化学物质是外源性的药理性的还是内源性的生理性的、Goldstein,etc.为当代的受体理论下了定义：药物作用于生物体的特殊分子组分即受体,产生特定效果;藉此,受体分子的功能随之调整,产生可测的效果;。

环境工程专业英语pollution污染a cid rain酸雨interaction of systems系统的交互作用environmental problem环境问题environmental disturbance环境破坏biotic habitat生物环境sulfur dioxide二氧化硫nitrogen oxide氧化氮carbon dioxide二氧化碳automobile exhaust汽车尾气infectious diseases有传染性的疾病waterborne diseases水传染的疾病agrarian society农业社会industrial society工业社会industrial revolution产业革命urbanization城市化industrialization工业化developed country发达国家developing country发展中国家undeveloped country落后国家primary air pollutant一次大气污染物secondary air pollutant二次大气污染物monoxide一氧化物dioxide二氧化物trioxide三氧化物carbon monoxide一氧化碳carbon dioxide二氧化碳sulfur dioxide二氧化硫sulfur trioxide三氧化硫nitrous oxide一氧化二氮nitric oxide一氧化氮nitrogen dioxide二氧化氮carbon oxides碳氮化物sulfur oxides硫氧化物nitrogen oxides氮氧化物hydrocarbons碳氢化合物photochemical oxidants光化学氧化物particulates颗粒物inorganic compound无机化合物organic compound有机化合物radioactive substance放射性物质heat热 noise噪声contaminant污染物 strength强度foreign matter杂质 domestic sewage生活污水municipal wastewater城市废水 microbe微生物microorganism微生物 bacteria细菌total solids总固体inorganic constituents无机要素suspended solids (SS)固体悬浮物volatile suspended solids (VSS)挥发性悬浮固体颗粒organic matter有机物质total organic carbon, TOC总有机碳chemical oxygen demand, COD化学需氧量biochemical oxygen demand, BOD生化需氧量biodegradable可微生物分解的contamination污染 recontamination再污染groundwater地下水 surface water地表水restriction限制 colloid胶体screening隔栅 coagulation凝聚flocculation絮凝 sedimentation沉淀filtration过滤 disinfection消毒chlorination氯化消毒 prechlorination预加氯ozonation臭氧消毒 aeration曝气softening软化 activated carbon活性炭adsorption吸附 reverse osmosis反渗透desalination脱盐处理microbial degradation微生物降解biological degradation生化降解biofilm process生物膜法activated sludge process活性污泥法attached-growth吸着生长suspended-growth悬浮生长shock loading冲击负荷organic loading有机负荷mixed liquor suspended solids混合液悬浮固体metabolize使代谢化metabolism新陈代谢dissolved oxygen 溶解氧pretreatment process 预处理工艺primary clarifier初沉池equalization basin均质池biological treatment process生物处理工艺aeration basin曝气池secondary clarifier二沉池biomass生物质heterotrophic bacteria异养菌autotrophic bacteria自养菌hydraulic retention time (HRT) 水力停留时间sludge residence time (SRT)污泥停留时间solid waste固体废物municipal城市化industrial工业的agricultural农业的hazardous危险的residential住宅的commercial商业的putrescibl e易腐烂的combustible易燃的flammable可燃的explosive易爆的radioactive放射性的Landfilling土地填埋 incineration:焚烧 composting: 堆肥 compaction: 压实，紧凑sanitary landfill卫生填埋 balance剩下的，余额，结余 batch-fed分批投料 refus e垃圾municipal waste城市垃圾perform: 执行 shut down:关闭 energy recovery能量回收incomplete combustion不完全燃烧combustion燃烧volume reduction体积缩小anaerobic厌氧硝化中英互译短语Biological degradation生化降解 equalization basin调节池 aeration basin曝气池sludge blocs污泥絮体 settling tank沉淀池 dissolved oxygen溶解氧suspended-growth悬浮生长 pulverized refuse垃圾破碎biofilm生物膜well-compacted landfill压实填埋场nutrient source营养源mass-burning大量燃烧fluidized fed incarceration硫化床燃烧法 soil conditioners土壤改良剂温室效应greenhouse effect 由CO2引起的caust by CO2 世界碳预算the world carbon budget 天气自然波动natural fluctuations 全球变暖global warming 厌氧的anaerobic腐烂Putrefied 甲烷methane 臭氧层ozone layer 气候模型climatic model正常浓度：normal concentration 严重污染物：heavily polluted 决定因素：determining factor光化学氧化物：photochemical oxidants 液体微滴：liquid particulates 含硫的：sulfur-containing放射性物质：radioactiue substance 汽车尾气：automobile exhaust wet oxidation湿式氧化1、Environment is the physical and biotic habitat which surrounds us; that which we can see, hear,touch, smell, and taste. 环境是我们周围的物理和生物环境，我们可以看到、听到、接触到、闻到和品尝到的。

微观生物学英文Microbiology is the study of microorganisms, which are microscopic organisms that include bacteria, viruses, fungi, and protozoa. It is a broad field that encompasses various disciplines, including bacteriology, virology, mycology, and parasitology. Microbiology plays a crucial role in understanding the fundamental aspects of life, disease processes, and the development of new treatments and technologies.Microorganisms are ubiquitous, meaning they can be found everywhere, including soil, water, air, and even within other organisms. They are incredibly diverse and have adapted to survive and thrive in various environments, ranging from extreme heat and cold to high pressure and acidity. Microorganisms play essential roles in various ecosystems, such as nutrient cycling, decomposition, and symbiotic relationships with other organisms.Bacteria are single-celled organisms that are among the most abundant and diverse microorganisms on Earth. They can be found in various shapes, including spheres (cocci), rods (bacilli), and spirals (spirilla). Bacteria have cell walls, and some possess flagella, which allow them to move. They can have beneficial or harmful effects on humans and other organisms. Some bacteria are used in food production, such as the production of yogurt and cheese, while others can cause diseaseslike pneumonia and tuberculosis.Viruses are non-living infectious agents that require a host cell to replicate. They consist of genetic material (DNA or RNA) surrounded by a protein coat. Viruses are responsible for a wide range of diseases in humans, animals, and plants, including the common cold, influenza, HIV/AIDS, and COVID-19. Understanding viral structure, replication, and transmission is crucial for developing effective antiviral therapies and vaccines.Fungi are eukaryotic organisms that include yeasts, molds, and mushrooms. They can be unicellular or multicellular and obtain nutrients through absorption. Fungi play important roles in decomposition, nutrient cycling, and the production of antibiotics and food products. However, some fungi can cause infections in humans, such as athlete's foot and candidiasis.Protozoa are single-celled eukaryotic organisms that are found in diverse habitats, including soil, water, and the bodies of other organisms. They can be classified into various groups based on their movement, such as amoeboid, flagellated, and ciliated protozoa. Some protozoa are free-living, while others are parasitic and can cause diseases like malaria and dysentery.Microbiology employs various techniques and tools to study microorganisms. These include microscopy, culturing techniques,molecular biology methods, and bioinformatics. Microbiologists also study the interactions between microorganisms and their environment, as well as their interactions with other organisms, including humans.Microbiology has numerous practical applications. It plays a crucial role in healthcare, as microbiologists help diagnose and treat infectious diseases by identifying the causative microorganisms and testing their susceptibility to antibiotics. Microorganisms are also used in biotechnology to produce medicines, enzymes, and biofuels. Additionally, microbiology is important in food safety, environmental monitoring, and the development of agricultural practices.In conclusion, microbiology is a diverse and fascinating field that focuses on the study of microorganisms. It provides insights into the fundamental processes of life, the causes and prevention of diseases, and the development of innovative technologies. By understanding microorganisms, we can harness their beneficial properties and mitigate their harmful effects, leading to advancements in various aspects of human life.微观生物学是研究微生物的学科，微生物是包括细菌、病毒、真菌和原生动物在内的微小生物体。

韩杰，蔡元奇，李欣，等.碳质材料载体对微生物的固定化作用及其在环境污染控制中的应用[J].沈阳农业大学学报，2023，54（1）：121-128.沈阳农业大学学报，2023，54(1)：121-128Journal ofShenyang Agricultural University http ：// DOI:10.3969/j.issn.1000-1700.2023.01.014收稿日期：2022-10-10基金项目：现代农业产业技术体系建设专项项目（CARS-01-51）第一作者：韩杰(1978-)，女，博士，副教授，从事生物炭在霉菌毒素脱除中的应用研究，E-mail:***************.cn通信作者：孟军(1977-)，男，博士，教授，博士生导师，从事生物炭应用研究，E-mail:********************.cn 碳质材料载体对微生物的固定化作用及其在环境污染控制中的应用韩杰a ，蔡元奇a ，李欣a ，翟旻a ，黄明华a ，孟军b（沈阳农业大学a.动物科学与医学学院，b.农学院/水稻研究所/国家生物炭研究院/农业农村部生物炭与土壤改良重点实验室，沈阳110161）摘要：微生物的生物吸附和生物降解作用因具有高效低毒、特异性强、环境友好、价格低廉、易于工业化生产等特点而成为治理环境污染物的重要发展方向。

然而，在实际生产中直接应用游离微生物常常受限于环境因素导致的微生物活性下降以及由此造成的生物修复效率降低的难题。

微生物固定化技术通过吸附、包埋和交联等方式将微生物限定在适宜的载体空间内，可以有效提高微生物的环境抵抗力和代谢活性。

载体作为影响固定化微生物活性和生物量，进而制约微生物固定化技术成功实施的关键因素，加强碳质材料包括生物炭、活性炭、碳纳米管和石墨烯及其衍生物等的微生物固定化载体的开发成为具有广阔前景的研究方向。

相比于其他载体材料，碳质材料载体具有高稳定性、不溶性、高机械强度、良好的孔隙度、较大的比表面积和可以修饰调节的表面功能，有利于微生物在材料表面附着和生长以及在其内部繁殖和发育，为承载微生物奠定了良好的基础，已被广泛应用于环境保护、生物制药、农业生产、食品工程等领域的环境污染物去除和以促进生产为目的的实践应用中。

unit oneDistribution system分配系统Grid system 环状管网ring system环状管网loop feeder 环状管网branching system 枝状管网combination system 联合管网（combined system）Topography地形学，地形，地貌，地势dead end死水点feeder 给水管，进料器Elevation地面标高valve 阀门，真空管water supply 给水，自来水，供水系统service reservoir 配水池（调节水池）pump 泵storage element （储水）构筑物70m head 70米水柱leakage rate 泄漏量（泄漏率）hydraulic 水力的，水压的hydraulic analysis 水力分析field measurement 现场测量（实测）field date 实测数据key point管网节点pipe junctions 管网节点node （key point, junction）节点sign convention符号规约positive clockwise 取顺时针方向为正head loss 水头损失iterative solution 迭代解loop method 环路法flow, runoff, discharge 流量Sanitary 环境卫生的（尤指清除废物）Sewer 下水道，污水管Sanitary sewer 生活污水管道Connection连接管，排出管Cast-iron pipe 铸铁管（补充内容）PVC 聚氯乙烯Grade line 坡度线slope 倾斜度，坡度collecting sewer 污水支管Interceptor 截流污水管（intercepting sewer）Domestic民用的，生活的Manhole 人孔，检查井drainage 排污系统，排水装置，下水道sewerage system 污水工程系统invert 管道内底Pump station 泵站unit twoContaminant 污染物ground water 地下水surface water 地表水wastewater 污废水Floating materials漂浮物suspended materials悬浮物Colloidal materials 胶体物质colloidal particles 胶体微粒Dissolved materials 溶解物质Dissolved gases 溶解气体Microorganisms微生物（microbe）organic and inorganic constituents 有机和无机成分hardness-ion 硬度离子hardness 硬度carbon dioxide二氧化碳hydrogen sulfide 硫化氢Alga(algae) 水藻，藻类Clay 粘土silt泥沙，淤泥pathogenic病原体，致病菌，病原菌Bacteria 细菌Ammonia 氨，氨水Methane gas甲烷，沼气turbidity 浊度taste 味odor 臭drinking water 饮用水water sample 水样suspension 悬浮液turbidity unit (TU) 浊度单位turbidimeter 浊度表，浊度仪Solubility 溶度，溶解性Metabolism 新陈代谢standard color solution 标准比色液threshold odor number 臭阈值boiler feed water 锅炉给水boiler water supply锅炉给水demineralize 去除矿物质scale deposit 水垢，积垢Outfall 出水口，排水口chemical clarification 化学（法）澄清coagulation 混凝coagulant 混凝剂sedimentation 沉淀filtration 过滤disinfection 消毒synthetic polymer 合成聚合物Activated carbon 活性炭Chlorine 氯sedimentation basin 沉淀池oxidize 使氧化，使生锈soften 软化settle-able 会沉淀的Aeration曝气通风unit threeplain settling 自由沉淀detention time 滞留时间Flocculation 絮凝Flocs 絮凝体coagulant aid 助凝剂(flocculation aid) natural alkalinity 自然碱度high-molecular compound 高分子化合物jar test 烧杯实验Centrifugal 离心的low-lift pump 低扬程水泵suction line 吸入管线索impeller 叶轮pump casing 泵壳Paddle-type flocculator 桨板式絮凝器（池）Clarifier 澄清池up flow clarifier 升流式澄清池contact tank 接触反应池Sedimentation basins 沉淀池inlet baffle 进水挡板effluent weir 出水堰tube settler 管式沉淀池influent flow 入流reaction jet structure 喷流结构finger launder 指形槽结构effluent launder 出流槽cross baffle 横向挡板settling tank 沉淀池（settler）aqueous suspension 水悬浮液shallower basin 浅池parallel-plate settler 斜板沉淀池tube settler 斜管沉淀池feed rate 这里指水流速度laminar flow 层流filter medium 过滤介质（滤料）anthracite 无烟煤mixed-media 复合滤料back-wash 反冲洗hydraulic grading水力分级High-Rate Sedimentation Basins 高效澄清池Slow and Rapid Sand Filter慢砂滤池和快砂滤池Mixed-media Filter 复合滤料滤池specific gravity 比重filter cycle 过滤周期oxidation potential 氧化电势，氧化性reduction potential 还原电势，还原性ozone 臭氧Oxidant 氧化剂Reducer 还原剂germicidal property杀菌能力（germicide杀菌剂）molecular weight 分子量Halogen 卤素pilot 试验性的Chlorination 氯化，用氯处理water-borne disease 水传播病THM S三卤甲烷breakpoint chlorination 折点加氯breakpoint dosage折点剂量free (available) chlorine 自由性氯chlorine demand 需氯量combined chlorine 化合性氯unit fourWater Pollution水污染Organic wastes有机废物municipal waste 市政污水Dissolved oxygen 溶解氧（DO）slightly soluble 微溶于水的Saturation 饱和状态saturation concentration 饱和浓度biochemical oxygen demand (BOD)生化需氧量pollutant 污染物Biodegradable 可生物降解的chemical oxygen demand (COD) 化学需氧量oxidizing agent 氧化剂wastewater treatment plant 污水处理厂total suspended solids （TSS）总悬浮固体mixed liquor suspended-solids(MLSS) 混合液悬浮固体浓度volatile suspended solids (VSS) 挥发性固体wastewater analysis 污水水质分析water pollution control水污染控制Anaerobic 厌氧菌的，厌氧引起的Aerobic 需氧的，好氧的unit fivePrimary treatment 一级处理screen 格栅grit chamber 沉砂池settler 沉淀池V-notch weir三角堰primary clarifier 初沉池turbulence 紊流primary effluent 一级出水secondary treatment 二级处理biological treatment system 生物处理系统activated-sludge system 活性污泥系统aeration basin 曝气池return activated sludge （RAS）回流污泥air diffuser 空气扩散器step aeration activated-sludge process 阶段曝气活性污泥法BOD-SS loading BOD污泥负荷mixed liquor suspended-solids(MLSS) 混合液悬浮固体浓度sequential batch reactor (SBR) 序批式（间歇式）活性污泥法primary clarifier 初沉池secondary clarifier 二沉池Sludge treatment 污泥处理volume reduction 减量化Sludge thickening 污泥浓缩gravity thickener重力浓缩池sludge scraper 刮泥器Sludge digestion 污泥消化methane-forming bacteria产甲烷菌。

environmental microbiology分区what environmental microbiology is, its significance in studying the environment, the techniques used in this field, the research areas within environmental microbiology, and future prospects and challenges.Environmental microbiology is a branch of microbiology that deals with the study of microorganisms in their natural habitats and their effects on the environment. Microorganisms are ubiquitous in the environment and play a crucial role in the functioning of ecosystems. Studying environmental microbiology is not only essential to understand the diversity and dynamics of microbial communities but also to investigate their interactions with the environment.One of the major reasons environmental microbiology is significant is its role in biogeochemical cycles. Microorganisms are involved in various biological processes, such as nitrogen fixation, carbon cycling, and decomposition of organic matter. For example, nitrogen-fixing bacteria convert atmospheric nitrogen into a usable form for plants, which is an essential component of the nitrogen cycle. In understanding these processes, scientists can develop strategies to optimize them for environmental management and sustainable agriculture.Techniques used in environmental microbiology include both culture-dependent and culture-independent methods. Culture-dependent methods involve isolating and growing microorganisms in laboratory conditions. This allows researchers to study the morphology, physiology, and biochemical characteristics of individual microorganisms. However, this technique is limited to the microorganisms that can be cultivated in the laboratory, which represents only a small fraction of the total microbial diversity.Culture-independent methods, on the other hand, have revolutionized the field by allowing the study of the entire microbial community without the need for cultivation. These methods include DNA-based techniques such as polymerase chain reaction (PCR), metagenomics, and amplicon sequencing. PCR amplifies specific DNA sequences, allowing identification and quantification of microorganisms present. Metagenomics involves sequencing DNA directly from environmental samples to obtain a comprehensive view of the microbial community. Amplicon sequencing focuses on specific marker genes, such as the 16S rRNA gene for bacteria, to characterize the microbial diversity in different environments.Environmental microbiology encompasses various research areas. One area of study is the microbial degradation of pollutants. Microorganisms are known to play a critical role in the breakdown of toxic chemicals such as hydrocarbons, pesticides, and heavy metals. Understanding the mechanisms behind microbial degradation can inform strategies for bioremediation, the use of microorganisms to clean up contaminated environments.Another research area is the study of microbial diversity and community structure. This involves investigating the factors that shape microbial communities, such as environmental conditions, geographical location, andhost-microbe interactions. By characterizing microbial communities and their dynamics, scientists can gain insights into ecosystem functioning and microbial ecology.Environmental microbiology also encompasses the study of microbial interactions with plants, animals, and humans. For example, the rhizosphere is the region of soil surrounding plant roots, which contains a rich diversity of microorganisms that interact with plants. Understanding these interactions can lead to the development of microbial-based biostimulants and biocontrol agents for sustainable agriculture.The field of environmental microbiology has future prospects and challenges. With advancements in sequencing technologies, there will be an increasing ability to analyze complex microbial communities and their functions. Additionally, the integration of multi-omics approaches, such as metatranscriptomics and metabolomics, will provide a more holistic understanding of microbial activities in the environment.However, challenges exist in analyzing the vast amount of sequencing data generated from environmental samples and interpreting the functional relevance of microbial communities. Furthermore, the impact of climate change and anthropogenic activities on microbial communities and their functions needs further investigation. The field of environmental microbiology will continue to be at the forefront of addressing these challenges and providing insights into the role of microorganisms in maintaining the health of our environment.In conclusion, environmental microbiology is a vital field of study that investigates the role of microorganisms in the environment. It is significant in understanding biogeochemical cycles, developing strategies for environmental management,and improving sustainability. The techniques used in this field, including culture-dependent and culture-independent methods, have provided valuable insights into the diversity and dynamics of microbial communities. Environmental microbiology encompasses various research areas, from microbial degradation of pollutants to the study of microbial interactions with plants and animals. Despite future prospects, challenges exist in analyzing sequencing data and understanding the functional relevance of microbial communities. Nonetheless, the field will continue to advance our knowledge of microorganisms and their impact on the environment.。

你想发明生物分解净化作文450英文回答：Biodegradation is a process that involves the breakdown of organic substances by living organisms, such as bacteria and fungi. This natural process plays a crucial role in the purification of various environmental pollutants, including organic waste, oil spills, and chemical contaminants. The ability of certain microorganisms to break down these substances into simpler compounds allows for theirrecycling and removal from the environment.One example of biodegradation in action is the decomposition of organic waste in landfills. When organic materials, such as food scraps and yard waste, are buriedin a landfill, they undergo biodegradation. Bacteria and other microorganisms present in the waste break down the organic matter, releasing carbon dioxide and other byproducts. This process not only reduces the volume of waste in landfills but also prevents the release of harmfulgases, such as methane, which contribute to climate change.Another example is the bioremediation of oil spills. When an oil spill occurs in a marine environment, it can have devastating effects on the ecosystem. However, certain bacteria have the ability to break down the hydrocarbons present in oil, converting them into less harmful substances. These bacteria can be introduced to the affected area to accelerate the biodegradation process and minimize the environmental impact of the spill.In addition to waste management and oil spill cleanup, biodegradation also plays a role in the removal of chemical contaminants from soil and water. For instance, certain bacteria can break down harmful pesticides and herbicides, transforming them into non-toxic compounds. This process, known as biodegradation, helps to restore the natural balance of ecosystems and safeguard human health.Overall, biodegradation is a powerful and natural process that has the potential to address various environmental challenges. By harnessing the capabilities ofmicroorganisms, we can develop innovative solutions for waste management, pollution control, and environmental restoration.中文回答：生物分解净化是一种通过生物体，如细菌和真菌，分解有机物质的过程。

体内微生物协同进化增强宿主抵抗力热心肠日报Molecular Biology and Evolution[IF:11.062]In vivo microbial coevolution favours host protection and plastic downregulation of immunity体内微生物协同进化有利于宿主保护和下调免疫功能的可塑性10.1093/molbev/msaa29211-12, ArticleAbstract & Authors:展开Abstract:收起Microbiota can protect their hosts from infection. The short timescales in which microbes can evolve presents the possibility that ‘protective microbes’ can take-over from the immune system of longer-lived hosts in the coevolutionary race against pathogens. Here, we found that coevolution between a protective bacterium (Enterococcus faecalis) and a virulent pathogen (Staphylococcus aureus) within an animal population (Caenorhabditis elegans) resulted in more disease suppression than when the protective bacterium adapted to uninfected hosts. At the same time, more protective E. faecalis populations became costlier to harbour and altered the expression of 134 host genes. Many of these genes appear to be related to the mechanism of protection, reactive oxygen species production. Crucially, more protective E. faecalis populations downregulated a key immune gene, sodh-1, known to be effective against S. aureus infection. These results suggest that a microbial line of defence is favoured by microbial coevolution and may cause hosts to plastically divest of their own immunity.First Authors:Suzanne A Ford,Suzanne A Ford Correspondence Authors: Suzanne A Ford,Suzanne A Ford All Authors:Suzanne A Ford,Suzanne A Ford。

转基因英语作文Title: Transgenic English Composition。

With the continuous development of biotechnology, transgenic technology has become a hot topic in the field of agriculture and food production. Transgenic technology refers to the process of introducing foreign genes into the genome of an organism to confer specific traits or characteristics. This technology has been widely used in the production of genetically modified crops, animals, and microorganisms.Transgenic technology has brought about significant changes in agriculture and food production. One of the most notable applications of transgenic technology is the development of genetically modified crops. Through the introduction of genes that confer resistance to pests, diseases, and herbicides, genetically modified crops have shown increased yields and reduced reliance on chemical pesticides and herbicides. This has not only improved theefficiency of agricultural production but also reduced the environmental impact of farming practices.In addition to pest and disease resistance, transgenic technology has also been used to enhance the nutritional value of crops. For example, the introduction of genes that increase the levels of essential vitamins and minerals in staple crops has the potential to address malnutrition and food insecurity in developing countries. Furthermore, the development of genetically modified crops with improved tolerance to environmental stress, such as drought and salinity, holds promise for ensuring food security in the face of climate change.Apart from crops, transgenic technology has also been applied to the production of genetically modified animals. For example, transgenic pigs have been developed with the aim of providing organs for xenotransplantation, which could potentially address the shortage of donor organs for human transplantation. Additionally, transgenic animals have been engineered to produce pharmaceutical proteins in their milk, offering a cost-effective and scalable methodfor the production of therapeutic proteins.Despite the potential benefits of transgenic technology, it has also sparked debates and controversies regarding its safety and ethical implications. Critics of transgenic technology raise concerns about the potential risks to human health and the environment, as well as the potential for unintended consequences such as the development of resistant pests and weeds. Furthermore, the patenting and commercialization of transgenic crops have raised questions about the control of agricultural resources and the impact on small-scale farmers and food sovereignty.In conclusion, transgenic technology has revolutionized agriculture and food production, offering the potential to address global challenges such as food security, malnutrition, and environmental sustainability. However, it is essential to carefully consider the potential risks and ethical implications associated with the use of transgenic technology. Through rigorous scientific research, transparent regulation, and inclusive public dialogue, the benefits of transgenic technology can be harnessed whilemitigating potential risks and ensuring ethical and sustainable practices.。

Microbial Biochemical Synthesis Microbial biochemical synthesis is a fascinating field that involves the useof microorganisms to produce valuable compounds through their metabolic processes. These compounds can range from antibiotics and enzymes to biofuels and bioplastics, offering a sustainable and environmentally friendly alternative to traditional chemical synthesis methods. The ability of microbes to efficiently convert simple raw materials into complex products has garnered significant interest in various industries, including pharmaceuticals, agriculture, and biotechnology. One of the key advantages of microbial biochemical synthesis is the ability to harness the diverse metabolic capabilities of different microorganisms. By selecting the right strain and optimizing growth conditions, researchers can tailor the production process to yield high quantities of the desired compound. This flexibility allows for the production of a wide range of products, each with unique properties and applications. Additionally, the use of microbial systems often results in higher product yields and purity compared to chemical synthesis, making it a cost-effective and sustainable option for industrial production. In addition to its economic benefits, microbial biochemical synthesis also offers environmental advantages. Unlike traditional chemical processes that rely on harsh solvents and generate toxic byproducts, microbial synthesis is typically carried out under mild conditions using renewable resources. This reduces the carbon footprint of the production process and minimizes waste generation, aligning with the principles of green chemistry. Furthermore, the use of microbial systems can help reduce the reliance on fossil fuels by enabling the production of biofuels and bioplastics from renewable feedstocks. Despite its many advantages, microbial biochemical synthesis is not without challenges. One of the main hurdles is the optimizationof production processes to achieve high yields and productivity. This often requires extensive research and development to fine-tune growth conditions,nutrient availability, and metabolic pathways to maximize product formation. Additionally, the scalability of microbial production systems can be a limiting factor, as upscaling from lab-scale to industrial-scale production can pose technical and economic challenges. Another challenge in microbial biochemical synthesis is the potential for genetic instability and the risk of contamination.Microorganisms can mutate and lose their ability to produce the desired compound, leading to a decrease in product quality and yield. Contamination with other microorganisms can also affect the purity of the final product and pose a risk to human health. To mitigate these risks, stringent quality control measures and monitoring systems must be implemented throughout the production process. In conclusion, microbial biochemical synthesis holds great promise for thesustainable production of valuable compounds with diverse applications. By harnessing the metabolic capabilities of microorganisms, researchers can develop efficient and environmentally friendly production processes that offer economicand environmental benefits. While there are challenges to overcome, ongoing research and technological advancements continue to drive innovation in this field, paving the way for a more sustainable future.。

Microbial Biotechnology Sample Microbial biotechnology is a rapidly growing field that has the potential to revolutionize the way we produce food, medicine, and other essential products. Microbes are tiny organisms that play a crucial role in many biological processes, and scientists have been harnessing their power for decades to create new and innovative products. In this essay, I will explore the different applications of microbial biotechnology, the benefits and risks associated with this field, andthe ethical considerations that must be taken into account. One of the most promising applications of microbial biotechnology is in the production of biofuels. With the world's growing energy demands and the need to reduce our carbon footprint, biofuels offer a sustainable and renewable alternative to fossil fuels. Microbes are used to convert organic matter, such as plant waste and agricultural byproducts, into biofuels like ethanol and biodiesel. This process is known as fermentation, and it has the potential to significantly reduce our dependence on non-renewable energy sources. Another area where microbial biotechnology is making a significant impact is in the production of pharmaceuticals. Many drugs, including antibiotics, are produced using microbes like bacteria and fungi. Scientists are also exploring the use of genetically modified microbes to produce new and more effective drugs. For example, researchers are using CRISPR geneediting technology to modify bacteria to produce insulin, a hormone used to treat diabetes. While microbial biotechnology offers many potential benefits, there are also risks associated with this field. One of the primary concerns is thepotential for genetically modified microbes to escape into the environment and cause harm. For example, if a genetically modified microbe designed to break downa specific pollutant were to escape into the wild, it could potentially disruptthe ecosystem and cause unintended consequences. Additionally, there is the risk that genetically modified microbes could be used for nefarious purposes, such as bioterrorism. Another ethical consideration is the use of microbes in animal agriculture. Many farmers use antibiotics to prevent disease in their livestock, but this practice can lead to the development of antibiotic-resistant bacteria. Scientists are exploring the use of microbial biotechnology to create alternatives to antibiotics, such as using probiotics to promote healthy gut bacteria inlivestock. However, there are concerns about the safety and efficacy of these alternatives, as well as the potential impact on animal welfare. In conclusion, microbial biotechnology is a rapidly advancing field with many potential applications in areas like biofuels, pharmaceuticals, and animal agriculture. While there are risks associated with this field, the benefits of using microbes to create sustainable and renewable products are significant. As we continue to explore the potential of microbial biotechnology, it is essential that we also consider the ethical implications and take steps to ensure that this technology is used safely and responsibly.。

SymbiosisThis article is about the biological phenomenon, for other uses seeSymbiosis (disambiguation)Clownfish amid sea anemone tentaclesThe term symbiosis(from the Greek:σύνsyn"with"; andβίωσιςbiosis"living")commonly describes close and often long-term interactions between different biologic-al species.The term was first used in1879by the Ger-man mycologist Heinrich Anton de Bary,who defined it as "the living together of unlike organisms."[1][2] The definition of symbiosis is in flux,and the term has been applied to a wide range of biological interac-tions.The symbiotic relationship may be categorized as being mutualistic,parasitic,or commensal in nature.[3][4]Others define it more narrowly,as only those relationships from which both organisms benefit, in which case it would be synonymous with mutual-ism.[5][6][7]Symbiotic relationships include those associations in which one organism lives on another(ectosymbiosis, such as mistletoe),or where one partner lives inside the other(endosymbiosis,such as lactobacilli and other bac-teria in humans or zooxanthelles in corals).Symbiotic relationships may be either obligate,i.e.,necessary for the survival of at least one of the organisms involved,or facultative,where the relationship is beneficial but not essential for survival of the organisms.[8][9] Physical interactionEndosymbiosis is any symbiotic relationship in which one symbiote lives within the tissues of the other,either in the intracellular space or extracellularly.[10][11] Examples are rhizobia,nitrogen-fixing bacteria that live in root nodules on legume roots;actinomycetenitrogen-Alder tree root nodulefixing bacteria called Frankia,which live in alder tree root nodules;single-celled algae inside reef-building corals;and bacterial endosymbionts that provide essen-tial nutrients to about 10%–15% of insects.Ectosymbiosis,also referred to as exosymbiosis,is any symbiotic relationship in which the symbiont lives on the body surface of the host,including the inner surface of the digestive tract or the ducts of exocrine glands.[12][13]Examples of this include ectoparasites such as lice,commensal ectosymbionts such as the barnacles that attach themselves to the jaw of baleen whales,and mutualist ectosymbionts such as cleaner fish.MutualismAnemone hermit crabThe term"mutualism"describes any relationship between individuals of different species where both in-dividuals derive a benefit.[14]Generally,only lifelong in-teractions involving close physical and biochemical con-tact can properly be considered symbiotic.Mutualistic relationships may be either obligate for both species,ob-ligate for one but facultative for the other,or facultativefor both.Many biologists restrict the definition of sym-biosis to close mutualist relationships.A large percentage of herbivores have mutualistic gut fauna that help them digest plant matter,which is more difficult to digest than animal prey.[15]Coral reefs are the result of mutualisms between coral organisms and various types of algae that live inside them.[16]Most land plants and land ecosystems rely on mutualisms between the plants,which fix carbon from the air,and mycorrhyzal fungi,which help in extracting minerals from the ground.[17]An example of mutual symbiosis is the relationship between the ocellaris clownfish that dwell among the tentacles of Ritteri sea anemones.The territorial fish protects the anemone from anemone-eating fish,and in turn the stinging tentacles of the anemone protect the clownfish from its predators.A special mucus on the clownfish protects it from the stinging tentacles.[18] Another example is the goby fish,which sometimes lives together with a shrimp.The shrimp digs and cleans up a burrow in the sand in which both the shrimp and the goby fish live.The shrimp is almost blind,leaving it vulnerable to predators when above ground.In case of danger the goby fish touches the shrimp with its tail to warn it.When that happens both the shrimp and goby fish quickly retract into the burrow.[19]One of the most spectacular examples of obligate mutualism is between the siboglinid tube worms and symbiotic bacteria that live at hydrothermal vents and cold seeps.The worm has no digestive tract and is wholly reliant on its internal symbionts for nutrition. The bacteria oxidize either hydrogen sulfide or methane which the host supplies to them.These worms were dis-covered in the late1980s at the hydrothermal vents near the Galapagos Islands and have since been found at deep-sea hydrothermal vents and cold seeps in all of the world’s oceans.[20]There are also many types of tropical and sub-tropical ants that have evolved very complex relationships with certain tree species.[21] CommensalismCommensalism describes a relationship between two liv-ing organisms where one benefits and the other is not significantly harmed or helped.It is derived from the English word commensal,meaning"sharing food"and used of human social interaction.The word derives from the medieval Latin word,formed from com-and mensa, meaning "sharing a table".[22][23]Commensal relationships may involve one organism using another for transportation(phoresy)or for hous-ing(inquilinism),or it may also involve one organism using something another created,after its death (metabiosis).Examples of metabiosis are hermit crabs using gastropod shells to protect their bodies and spiders building their webs on plants. ParasitismA parasitic relationship is one in which one member of the association benefits while the other is harmed.[24] Parasitic symbioses take many forms,from endopara-sites that live within the host’s body to ectoparasites that live on its surface.In addition,parasites may be necrotrophic,which is to say they kill their host,or bio-trophic,meaning they rely on their host’s surviving.Bio-trophic parasitism is an extremely successful mode of life.Depending on the definition used,as many as half of all animals have at least one parasitic phase in their life cycles,and it is also frequent in plants and fungi. Moreover,almost all free-living animals are host to one or more parasite taxa.An example of a biotrophic rela-tionship would be a tick feeding on the blood of its host.Symbiosis and evolutionLeafhoppers protected by an army of meat antsWhile historically,symbiosis has received less attention than other interactions such as predation or competi-tion,[25]it is increasingly recognised as an important se-lective force behind evolution,[26][27]with many species having a long history of interdependent co-evolution.[28]In fact,the evolution of all eukaryotes(plants,animals, fungi,and protists)is believed under the endosymbiotic theory to have resulted from a symbiosis between vari-ous sorts of bacteria.[29][30][31] SymbiogenesisThe biologist Lynn Margulis,famous for her work on en-dosymbiosis,contends that symbiosis is a major driving force behind evolution.She considers Darwin’s notion of evolution,driven by competition,as incomplete and claims that evolution is strongly based on co-operation, interaction,and mutual dependence among organisms. According to Margulis and Dorion Sagan,"Life did not take over the globe by combat, but by networking."[32] Co-evolutionSymbiosis played a major role in the co-evolution of flowering plants and the animals that pollinate them. Many plants that are pollinated by insects,bats,or birds have highly specialized flowers modified to promote pollination by a specific pollinator that is also corres-pondingly adapted.The first flowering plants in the fossil record had relatively simple flowers.Adaptive spe-ciation quickly gave rise to many diverse groups of plants,and,at the same time,corresponding speciation occurred in certain insect groups.Some groups of plants developed nectar and large sticky pollen,while insects evolved more specialized morphologies to access and collect these rich food sources.In some taxa of plants and insects the relationship has become dependent,[33] where the plant species can only be pollinated by one species of insect.[34]Notes[1]Wilkinson 2001[2]Douglas 1994, p.1[3]Dethlefsen L, McFall-Ngai M, Relman DA (2007). "Anecological and evolutionary perspective on human-microbe mutualism and disease".Nature449: 811–808.doi:10.1038/nature06245.PMID 17943117.[4]Paszkowski U. (2006). "Mutualism and parasitism: the yinand yang of plant symbioses".Curr Opin Plant Biol9:364–370.doi:10.1016/j.pbi.2006.05.008.PMID 16713732.[5]Wilkinson 2001[6]Isaac 1992, p.266[7]Saffo 1993[8]Moran 2006[9]Ahmadjian & Paracer 2000, p.12[10]Ahmadjian & Paracer 2000, p.12[11]Sapp 1994, p.142[12]Ahmadjian & Paracer 2000, p.12[13]Nardon & Charles 2002[14]Ahmadjian & Paracer 2000, p.6[15]Moran 2006[16]Toller, Rowan & Knowlton 2001[17]Harrison 2005[18]Lee 2003[19]Facey, Helfman & Collette 1997[20]Cordes 2005[21]Piper, Ross(2007),Extraordinary Animals: AnEncyclopedia of Curious and Unusual Animals,Greenwood Press.[22]Ahmadjian & Paracer 2000, p.6[23]Nair 2005[24]Ahmadjian & Paracer 2000, p.7[25]Townsend, Begon & Harper 1996[26]Wernegreen 2004[27]Moran 2006[28]Ahmadjian & Paracer 2000, p.3-4[29]Brinkman 2002[30]Golding & Gupta 1995[31]Moran 2006[32]Sagan & Margulis 1986[33]Harrison 2002[34]Danforth & Ascher 1997References•Ahmadjian, Vernon; Paracer, Surindar (2000),Symbiosis:an introduction to biological associations, Oxford[Oxfordshire]: Oxford University Press,ISBN 0-195-11806-5•Burgess, Jeremy (1994),Forum: What’s in it for me, NewScientist,/article/mg14119115.200-forum-whats-in-it-for-me--jeremy-burgess-examines-therole-of-cooperation-within-natures-competitive-ways-.html•Boucher, Douglas H (1988),The Biology of Mutualism:Ecology and Evolution, New York: Oxford University Press,ISBN 0195053923•Cordes, E.E.; Arthur, M.A.; Shea, K.; Arvidson, R.S.; Fisher,C.R. 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