实验动物相关论文题目有哪些英语翻译
灭绝灭绝是一个自然的过程。许多物种已经不复存在人类进化前。然而，在过去的400年，绝种的动物和植物的数量已达到危机点。人口的急剧上升，在同一时期，人的掠夺性的本能与他无情的消耗自然资源相结合，直接负责的情况。渡渡鸟渡渡鸟是一个典型的例子人类行为的，可以到地球的生物多样性造成不可挽回的损失。飞的渡渡鸟是原产于印度洋毛里求斯岛。生活从岛上的树木倒下的水果和生活unthreatened直到人类在1505年抵达。温顺的鸟成了水手的食物来源和缺乏能力，以保护动物，如猪，猴和大鼠人类在岛上。渡渡鸟人口迅速下降，并在1681年最后一个被杀害。濒危动物留在2002年许多动物面临灭绝的威胁，作为人类活动的结果。世界野生动物基金不知疲倦地工作，以提高这些动物面临的困境的认识，并找到方法来保护他们。由注重数量上的高调，“魅力的图标，如犀牛，大熊猫，鲸和虎，世界自然基金会旨在沟通，极为重要的环境问题”。该组织的最终目标是，停止地球的自然环境恶化，并建立在人类与自然和谐相处的未来。犀牛犀角是亚洲医药从业人员的高度珍视项目。这导致其自然栖息地被无情地猎杀动物。一旦在非洲和欧亚大陆广泛，最犀牛生活在受保护的自然公园和自然保护区。他们的人数在过去50年迅速下降，超过消失在20世纪70年代的一半，其余的犀牛，从偷猎者的不断威胁下保持和动物。
experimental animal
1， experimental animal breeding: experimental animal breeding research experimental animal genetic improvement and genetic control， and wild animals and livestock of experimental 2， experimental animal medicine: experimental animal medicine specialized experimental animal diseases diagnosis， treatment， prevention and it how in biomedical application 3 and comparative medical: comparative study of all animals， including man the similarities and differences between the basic life 4， experimental animal ecology: experimental animal living environment and conditions， such as animals houses， animal facilities， ventilation， temperature， humidity， light and noise， cage with， feed， water and various mat 5， animal experiment technology: the study of animal experiments various operating technology and experimental methods， including experimental animal raising management technology and itself of various monitoring technology，
Objective: To prepare chicken infectious anemia (Chicken infectious anemia， CIA) colloidal gold rapid diagnostic test strip Methods: 7 of 70 day-old SPF White Leghorn laying hens for the first time immunization with Freund's complete adjuvant， the antigen emulsion 2ml / only， points on both sides of the chest subcutaneous injection every 2 weeks after booster immunization 1， injection of Freund's Antigen in incomplete adjuvant emulsion 1ml / only a total of four immunization; 10d after the last immunization blood serum prepared by CIA， the serum antibodies were purified antibody preparation of colloidal gold and gold standard to determine the optimal concentration of gold labeled antibodies Results: The optimal concentration of the gold standard for the antibody to 214ug/ml Conclusion: The concentration of gold labeled antibodies in the detection of 214ug/ml best when the test Keywords chicken infectious anemia; serum antibody; colloidal gold test strip; gold standard antibody
实验动物相关论文题目有哪些英文翻译
The Shenzhen subject park culture characteristic construction searchesanalyzes Since Shenzhen 1989th year the exquisite silk China subjectpark establishment， already some 18 years year， has followed timepassing， the Shenzhen subject park development situation actuallyalready with difficulty is comparing with the same Very manyscholars have the suspicion to the subject park construction allnewspaper the Certainly， in these 18 years development， theShenzhen subject park indeed has many problems， the subject park whichthe manner knows very few may Therefore， searches to thesubject park analyzes into the very many domestic scholars' direction，for example: Guaranteed continues just gentleman in to the subjectpark development influence factor analysis in， thought the source oftourists market and the transportation condition， the region economylevel of development， the city traveling sensation image， the spacegathered with the competition as well as the policy-maker behavior inplays the indelible role to the subject park development Regardingthis， I carry on own on the subject park culture characteristicanalysis， as well as proposes own Key word: Traveling culture， cultural marketing， subject park
It is now mid-July， the village this evening in celebration of National D Children leaping around the bonfire of joy， when the sounds of the drum with each fireworks off alone in a dark corner， listening to the field of festival concerts， field programs than the programs staged in the village square is more The night was late night 9:00， the weather is cooler， the cicada is no longer It during the day and sing all day， evening fell， the rest， but the rest is often In the thick foliage of the plane trees， suddenly issued a whine like a short， sharp This is the desperate wail of cicadas in a quiet rest， night fanatical hunter green Grasshopper caught Let's stay away from the hustle and bustle to listen， and went to When caught cicadas are still struggling， the Indus trees on the program is still in progress， but the chorus has changed Now turn night artists Sensitive ears can hear the green leaves of the law of the jungle around at the Grasshopper in a whisper to That sound like a pulley， which was very interesting， vague rustling like dry wrinkled Mute and continuous bass， from time to time issued by a burst of very sharp and rapid， near-metal collision crisp sound， this is the katydid's song and music section， and the rest is the While singing the bass have been strengthened， the concert anyway， or humble， very Although in my ear， there are a dozen Grasshopper concert， but their voice is not strong， my ear's tympanic membrane is not able to capture a weak The Shino frogs and other insects is being produced， however， I can hear a little song is very soft and quiet atmosphere in the vast night， Green Grasshopper， if you pull the piano and then a loud a little bit， then you are even better than the cicada In northern China， it allows the cicada usurp your reputation! In June， I caught many male and female grasshopper in a metal This insect is very beautiful， covered with verdant side there are two pale white ribbon， tall and beautiful， slim shapely light， such as yarn， two large About food， I met the same trouble feeding I'll give them lettuce leaves， they eat a little， but do not I have to find another food， they are probably to be fresh meat， but what what is it? Morning， I walk in front of the Indus suddenly next to a tree behind what， at the same time there is a shrill squeak， I ran， it was a Grasshopper is pecking the belly of the cicadas in the I understand that the battle occurred in the morning cicadas still rest in the Unfortunately cicada alive bites， suddenly hop， the attackers and the attackers one fell down from the Sometimes I even see the Grasshopper is very brave to jump to hunt for cicada， cicada is in consternation flew Like an eagle in the sky in pursuit of the But this looting living birds than insects poor， it is weaker than it offensive things， and the Grasshopper on the contrary， it is offensive is much greater than their own， sturdy and much more animals， and this body size between the melee， the result is no Grasshopper has a strong jaw and sharp pliers， not captives disembowelling very rare， because cicada no weapon to refute， can only whine Green Grasshopper (3) the food of my cage prisoners to find， I use cicadas to feed Dish to eat with relish， so that the rest of the skull and sternum during the two or three stars， this cage full of cicadas meat was eaten， ripped off the wings and mutilation Stomach to be eaten whole， this is a good site， although not much meat， but it seems to taste especially Because in this location， in the crop， the accumulation of the cicada with its beak to suck from the tender branches to take the syrup sweet Because of this sweets cicadas in the stomach than other parts of the more popular? Very likely it will In order to transform the pattern of the food， I returned to Grasshopper eat the sweet fruit: a few slices of pears， a few grapes， a few pieces of They liked to Englishman loves to eat jam for condiments， bloody steak， green grasshopper fond of Maybe this is the first catch cicadas eat the reasons of the stomach， because both the belly meat， there are Is not anywhere to eat the cicada meat stick sugar， so something else to Scarab insects， it did not hesitate to accept， eat wings， head and claws What all this means katydid like to eat insects， especially insects， is not too hard armor It is very fond of meat， unlike mantis only eat Grasshopper this cicada the butcher in the meat and drink blood after eating the sweet pulp of the fruit， sometimes there is no good， and even eat a little Grasshopper also exists the phenomenon of Indeed， in my cage， I have never seen like a praying mantis killing and sisters， to devour her husband's brutality， but if a Grasshopper was dead， the living will not let the opportunity to taste his body， it like to eat a normal This is not because of lack of food， but because of greed only eat dead Putting that point aside， Grasshopper is very harmonious to each other and co-residence with the never quarrel between them at best to face the food a bit hostile I threw them into a pear， a Grasshopper immediately occupy Who bite a piece of delicious food， out of jealousy， it will kick the other Selfishness is everywhere Full， it will give way to another Grasshopper， then it is very One after another， all Grasshopper product to a After the crop is full， the beak tip scratched the soles of the feet and wiped his face and eyes stained saliva claws， and then his eyes closed or lying on the sand in the digestion of Most of the day to rest， especially in hot
灭绝灭绝是一个自然的过程。许多物种已经不复存在人类进化前。然而，在过去的400年，绝种的动物和植物的数量已达到危机点。人口的急剧上升，在同一时期，人的掠夺性的本能与他无情的消耗自然资源相结合，直接负责的情况。渡渡鸟渡渡鸟是一个典型的例子人类行为的，可以到地球的生物多样性造成不可挽回的损失。飞的渡渡鸟是原产于印度洋毛里求斯岛。生活从岛上的树木倒下的水果和生活unthreatened直到人类在1505年抵达。温顺的鸟成了水手的食物来源和缺乏能力，以保护动物，如猪，猴和大鼠人类在岛上。渡渡鸟人口迅速下降，并在1681年最后一个被杀害。濒危动物留在2002年许多动物面临灭绝的威胁，作为人类活动的结果。世界野生动物基金不知疲倦地工作，以提高这些动物面临的困境的认识，并找到方法来保护他们。由注重数量上的高调，“魅力的图标，如犀牛，大熊猫，鲸和虎，世界自然基金会旨在沟通，极为重要的环境问题”。该组织的最终目标是，停止地球的自然环境恶化，并建立在人类与自然和谐相处的未来。犀牛犀角是亚洲医药从业人员的高度珍视项目。这导致其自然栖息地被无情地猎杀动物。一旦在非洲和欧亚大陆广泛，最犀牛生活在受保护的自然公园和自然保护区。他们的人数在过去50年迅速下降，超过消失在20世纪70年代的一半，其余的犀牛，从偷猎者的不断威胁下保持和动物。
实验动物相关论文题目有哪些英语
建议使用CNKI系列数据库那里有非常详细的资料。 本体理论在动物学知识组织中的应用研究 作者：王好倩 学位授予单位：吉林大学 学位名称：硕士 学位年度：2007 新课程内容标准对生物教师动物学知识结构要求的研究 作者：李红梅 学位授予单位：云南师范大学 学位名称：硕士 学位年度：2006 替硝唑缓释剂的体外药物释放及其治疗牙周炎效果的动物学研究 作者：刘娟 学位授予单位：四川大学 学位名称：硕士 学位年度：2005 内蒙古大青山南部湿地鸟类生态学及民族动物学初步研究 作者：格日乐图 学位授予单位：内蒙古师范大学 学位名称：硕士 学位年度：2003 现代教育技术在高师生物专业《动物学》教学中应用的实验研究 作者：马纲 学位授予单位：西北师范大学 学位名称：硕士 学位年度：2002 德日进与中国古脊椎动物学 作者：舒群 学位授予单位：中国科学技术大学 学位名称：硕士 学位年度：1990 本体理论在动物学知识组织中的应用研究：以鸟类本体模型为例 作者：王好倩 学位授予单位：吉林大学 学位名称：硕士 学位年度： 冶炼厂周围重金属污染土壤生物指示研究 作者：王雪峰 学位授予单位：辽宁师范大学 学位名称：硕士 学位年度：2008 关键词：土壤动物学 含动物形象的俄语谚语、俗语分析 作者：吴丹 学位授予单位：天津外国语学院 学位名称：硕士 学位年度：2007 关键词：动物学 语言世界图景 人类中心论 对比性 语义分析 长白山北坡访花昆虫群落动态初步研究 作者：杜秀娟 学位授予单位：东北师范大学 学位名称：硕士 学位年度：2006 关键词：动物学 河川沙塘鳢（Odontobutis potamophila）的生殖系统发育及其繁殖行为研究 作者：赵晓勤 学位授予单位：华东师范大学 学位名称：博士 学位年度：2006 关键词：动物学 肌肉废用对黄鼠（Citellus dauricus）和大鼠比目鱼肌形态结构与肌纤维类型影响的比较研究 作者：王琦 学位授予单位：西北大学 学位名称：硕士 学位年度：2006 关键词：动物学 剑角蝗科8种蝗虫触角显微结构研究 作者：刘淼 学位授予单位：东北师范大学 学位名称：硕士 学位年度：2006 利用ISSR和COI序列标记分析不同地理仿刺参群体的遗传多样性 作者：闫晗 学位授予单位：辽宁师范大学 学位名称：硕士 学位年度：2006 关键词：海洋动物学 山地次生林中大山雀窝卵数与繁殖成功的关系 作者：苏循瑞 学位授予单位：东北师范大学 学位名称：硕士 学位年度：2006 关键词：动物学 施氏鲟（Acipenser schrenckii）幼鱼对盐度的适应性及其脂肪营养需求研究 作者：侯俊利 学位授予单位：华东师范大学 学位名称：博士 学位年度：2006 关键词：动物学 现生介形类动物系统发生及太湖介形类动物群落结构研究 作者：禹娜 学位授予单位：华东师范大学 学位名称：博士 学位年度：2006 关键词：动物学 中华鳖对饲料蛋白质水平适应性研究 作者：齐占会 学位授予单位：河北师范大学 学位名称：硕士 学位年度：2006 关键词：动物学 薄荷饮治疗温病卫分证的实验研究 作者：赖鹏华 学位授予单位：福建中医学院 学位名称：硕士 学位年度：2005 关键词：动物学 广西淡水鱼类物种多样性及动物地理学分析 作者：王丹 学位授予单位：中国科学院动物研究所 学位名称：硕士 学位年度：2005 关键词：动物学 几株芽孢杆菌肉鸡代谢研究 作者：韩秋霞 学位授予单位：山东师范大学 学位名称：硕士 学位年度：2005 关键词：动物学 两种幽灵蛛的行为学研究 作者：陈海峰 学位授予单位：中国科学院动物研究所 学位名称：硕士 学位年度：2005 关键词：动物学 绿色荧光蛋白转基因小鼠的建立及可视化胚胎工程的研究 作者：徐艺玫 学位授予单位：第一军医大学 学位名称：硕士 学位年度：2005 关键词：实验动物学 三氯杀螨醇对中华大蟾蜍的毒性和雌激素效应 作者：唐超智 学位授予单位：陕西师范大学 学位名称：硕士 学位年度：2005 关键词：动物学 塔里木兔的种群遗传结构研究 作者：李增超 学位授予单位：中国科学院动物研究所 学位名称：硕士 学位年度：2005 关键词：动物学 蚜科Aphididae及扁蚜亚科Hormaphidinae的分子系统学和进化研究 作者：任珊珊 学位授予单位：中国科学院动物研究所 学位名称：硕士 学位年度：2005 关键词：动物学 中国尺蛾亚科系统分类学研究（鳞翅目：尺蛾科） 作者：韩红香 学位授予单位：中国科学院动物研究所 学位名称：博士 学位年度：2005 关键词：动物学 中国皿蛛科蜘蛛分类学研究 作者：图立红 学位授予单位：中国科学院动物研究所 学位名称：博士 学位年度：2005 关键词：动物学
松鼠 松鼠是一种美丽的小动物，很讨人喜欢它四肢灵活，行动敏捷玲珑 的小面孔上，嵌着一对闪闪发光的小眼睛身上灰褐色的毛，光滑得好象搽过油一条毛茸茸的大尾巴总是向上翘着，显得格外漂亮 松鼠喜欢在树枝上跳来跳去，十分机灵只要有人触动一下树干，它们就躲在数枝底下，或连蹦带跳地逃到别的树上去晴朗的夏夜，松鼠在树上高兴的跳着叫着，互相追逐嬉戏它们好像怕强烈的日光，白天常常躲在窝里歇凉;只在树枝被风刮得乱摇晃的时候，它们才到地面上来但是从来不接近人的住宅 松鼠喜欢住在高大的老树上，常常把窝搭在树叉中间它们搭窝的时候，先搬来一些小数枝，交错着放在一起，再找一些干苔藓铺在上面，然后把苔藓压紧，踏平窝搭好了，还在上面加一个盖，把整个窝遮蔽起来，这样就不怕风吹雨打了她们带着儿女住在里边，又暖和又安全 松鼠常吃的食物是松子，榛子和橡栗，有时候也吃鸟蛋它们吃东西的时候，常常直着身子做在树枝上，用前爪捧着往嘴里送秋天，松鼠就储藏过冬的食物，把它塞到老树的缝隙里，塞得满满的冬天，它们有时候也用爪子扒开厚厚的积雪寻找雪底下的食物 松鼠的肉可以吃，尾巴上的毛可以制画笔，皮可以做衣服 青蛙捕食 我非常喜欢青蛙。夏天，我常常去池塘边看青蛙。 青蛙很喜欢躲在草丛里，偶尔也叫几声。它们叫得最欢的时候是在大雨过后。每当这时如果有一只叫，旁边的也就随着叫了起来。几十只甚至上百只青蛙“呱呱”叫个不停，那声音能够传到几里地以外，多像一曲气势磅礴的交响乐呀！ 青蛙的身体胖胖的，有的身体足有七八厘米长。它们披着黄绿色或深绿色的衣裳，露着雪白的肚皮。它们的头又宽又扁，像一个三角形。它的头上鼓着一双圆溜溜的大眼睛，长着大嘴巴、小鼻子。 青蛙爱吃小昆虫，观察它捕食的动作才有趣呢。有一天，我静静地蹲在池塘边上的大树后面，细心地观察着。一只青蛙蹲在地上，张着嘴巴仰着脸在等待着什么。突然，一只小虫飞过来，只见青蛙猛地向上一窜，舌头一钩，又落在地上。小虫不见了，青蛙又恢复了原来的样子，耐心地等待着。 青蛙可真是个捉虫的能手，听农民伯伯说：要是算起来，一只青蛙一年之内最少可以消灭一万只害虫。它真是我们的好朋友啊！ 小狗 小狗的警惕性非同寻常，它有一个特别灵敏的鼻子，能闻到3里以外东西的气息，吃食物时，它总要低下头闻一闻。它还有一双耳朵，每当听到特别的声音，它的耳朵总会竖起来，认真地倾听着外面的动静！因而，人们养它来看大门，它是人类的忠实的朋友。 小狗有一张宽而大的嘴巴，嘴里有一排洁白而又锋利的牙齿，它一口就可以将一只大老鼠咬死！ 小狗有着矫健的四肢，它跑得速度非常快，一分钟可以跑二、三里路呢！ 小狗的眼睛不很好，大约只能看一里的距离。那么，它为什么能看准东西呢？它主要靠得是它的鼻子。 小狗的爪子很锋利，不用多长时间，它就可以挖一个很大的圆形的坑。 小狗刚生下来的时候，毛是棕色的，可是它长大以后就不再是棕色的了，而变成了深黄色。 小狗的性格非常温和。如果你对它好，它就会用头顶你的腿，好像是在向你撒娇；可是如果是陌生人来到它的家里，它仍会“汪汪”地叫个不停，甚至会扑到你身上咬伤你的。 夏天到了，大热天，我们常常可以看见狗总是在吐舌头，而不见狗出汗呢？原因很简单，那是因为狗的汗孔长在舌头上。 小狗真不愧为人们所喜爱，这是它用自己真正的本领换来的 小公鸡 我很喜欢我家的那只喔喔叫的小公鸡。它的头上长着像火把一样的冠子。背上的羽毛像穿着深红闪亮的外衣。腹部的羽毛像套了件金黄色的衬衫。一双透亮灵活的眼睛和一张尖尖的嘴，再配上最引人注目的那五颜六色的大尾巴，显得既美丽又威武。 小公鸡早上起来就站在坪台上“喔喔”地使劲叫，催人们快快起床。 平时，小公鸡还是捉虫子的能手呢！尽管有些小虫十分机敏，但只要它动一下，就逃不过小公鸡的眼睛。有一次，我亲眼看见一条小虫子刚刚从树下的草丛中爬出来散步，就让小公鸡发现了。只见小公鸡飞快地跑到树下，用它那尖利细长的嘴巴，一下子就把小虫子捉住了，就这样一条条小虫子都成了小公鸡的美餐。 有一次放学回家，我看见小公鸡在院子里的大树下扒食吃，就连忙放下书包，抓了一把米撒在地上让它吃。小公鸡正吃得欢，不知谁家的一只大公鸡过来和小公鸡抢米吃。这下可把小公鸡惹火了，就扑过去和那只大公鸡打起架来。大公鸡猛地扑过来了，小公鸡沉着应战，身子一缩，躲过了大公鸡的一招。然后，它立刻转到大公鸡的后边，冷不防地向上一蹿，蹦到大公鸡的背上对着它的冠子猛啄，啄得大公鸡的冠子直流血。大公鸡疼得逃跑了。小公鸡胜利了，它昂头挺胸。瞧，一副得意神气的样子，真讨人喜欢。 我格外喜欢这只美丽、可爱的小公鸡。 小白猪 我家养了两头小白猪。它们全身雪白，一对大耳朵像两把有力的扇子，忽上忽下不停地扇动；鼻子长长的，一对圆圆的鼻孔，像两个小山洞；鼻子下面藏着个大嘴巴，不仔细看，真不会发现鼻子下面还有张嘴；鼻子上面有一双让人捉摸不透的小眼睛，满脸的皱纹，实在不怎么好看。 农忙时，妈妈下地干活，让我在家喂它们。我把猪圈门打开，把调好的食料放在猪圈门口，馋嘴的小猪鼻子尖极了，香味早被它们嗅到了，还没等我把猪食倒在食盆里，它们就一拥而上，把满满的一盆猪食给拱洒了。猪食溅到我脸上、裤腿儿上、褂子上，气得我顺手拿起棍子想揍它们。可刚举起棍子，它们就“嗷嗷”地叫起来，似乎在向我求饶。看着它们那可怜的样子，我又不忍心让棍子落下去了。 小白猪渐渐长大了，更暴露出了它们的本性－－贪吃、贪睡。每当妈妈喂它们时，它们便狼吞虎咽，大口大口地吃起来，还不停地发出哼哼声。吃饱了，就挺着滚圆的大肚子，用脚把土扒到身子底下，倒头就呼呼地睡起来。 小猪刚来我家时总惹人生气。或许是因为环境陌生的缘故，它们一次又一次勇敢地翻越猪圈往外跑，可是大门插得死死的，怎么也不能超越第二道防线跑出去。过了一两天，它们也就老实了，找个水窝，用嘴拱啊拱，然后躺在里面，还不停地弄得泥水飞溅，当然小白猪也就变成小泥猪了。家中的人不管它们在院子里如何折腾，只要它们不往外跑，就谢天谢地了。 有时候，它们又让人哭笑不得。一天上午，爸爸要垫猪圈，就把它俩赶到院子里。它俩刚从猪圈里出来，就满院子撒欢儿，吓得几只母鸡满院惊飞，“咯咯”地叫。再看它俩，什么也不顾，好像终于得到自由似的，又好像来到了一个新的世界，一会儿到炭堆里去乱拱，弄得灰头灰脸的，一会儿又拱拱小树、弄弄花草。一上午，整个院子被折腾得不成样子。可能是折腾累了吧，晌午，它们好不容易趴在暖和的地方呼呼睡起了大觉。 我家的小白猪虽然贪吃贪睡又淘气，但我仍然十分喜欢它们，因为它们给我增添了无穷的乐趣。 蚂蚁 一身黑亮的盔甲，两根细长的触角，凑成黑色的勇敢的小生灵--蚂蚁。 每当漫步在金色的校园，便会发现几个小小的“!”从我脚旁绕过，那就是蚂蚁。它似乎没有意识到身旁的庞然大物，仍旧慢悠悠地散步，那傲慢的步态不由刺动了我的自尊心，小小的蚂蚁竟敢在我面前摆架子。不必发生流血事件，只须用根小柳条轻轻地在它那两根“天线”上拨动一下，它便会吓得四处乱闯。这时我就会觉得像战胜了什么强大敌人一般兴奋，不过它毕竟是一只小小的蚂蚁呀。 也许因为我的顽皮，竟然和那么善良、那么弱小的蚂蚁发动什么“战争”，这对它显然是不公平的。 但自从我看了一则有关蚂蚁的趣闻之后，就不禁对这小生灵产生一种敬仰的情感。这则趣闻就是：世界上什么动物力气最大?答案是蚂蚁，因为蚂蚁可以背动比自身重量重6倍的物体。即使比蚂蚁重100倍的重物对于人来说也不过是举手之劳，但对于小蚂蚁来说就是要完成一项伟大的工作了。小生灵啊小生灵，没想到你小小的身躯竟蕴藏着如此巨大的力量。 随遇而安，辽阔而肥沃的大地就是蚂蚁舒适的家。一个个小生灵结合成了蚂蚁这个强大的家族。工蚁、蚁王，各尽所能，但并不“按劳分配”。工蚁成年累月辛苦劳作，侍奉蚁王，喂养幼蚁，直到心衰力竭地死去，而蚁王却作威作福，过着养尊处优的生活，真是太不公平了。我不免为工蚁的命运鸣不平，真希望有一天和平的阳光能照进黑暗的蚁穴。 这就是我喜爱的黑色的小生灵--蚂蚁。 猫 猫是人们宠爱的小动物，它温驯，活泼，可爱，能捉老鼠，博得主人的欢心。 刚出生的小猫，眼睛闭着，叫声细弱，浑身光秃秃的，好似一个会蠕动的肉团团。 满月以后，绒毛才全部长齐。有的颈圈是白色，四肢长满白毛，背部黑中杂有灰白，尾巴灰黑；有的从头到尾披一件油墨“大氅”，脚掌却是白色，人们说是良种，叫“乌云盖雪”；有的通体黄色，现虎斑纹，人们给它美名“金不换”；还有一身白毛配上一条黑毛尾巴的，被称为“雪里拖枪”。刚满月的猫离不开奶，走路也不稳。 猫吃的是杂食，最爱鱼和瘦肉，倘若扔一个水果或蔬菜之类的给它，它只是嗅一嗅便走开了。 猫的脚掌生有肥厚而柔软的肉垫，走路悄然无声，不致惊跑鼠类。脚趾末端生有锐利的钩爪，可以随意伸缩。这使它不但能在平地上疾走如飞，还能沿壁上房，爬树跳墙。老鼠被迫得丧魂落魄，很少能逃脱厄运。 猫的牙齿尖锐如锥，舌面粗糙，有许多倒刺。一旦逮住老鼠，猫爪抓刺，猫齿撕咬，顷刻之间，作恶多端的老鼠就开肠破肚，血肉狼藉。 猫的这些身体结构特征，使它具备了捕鼠的各种优越条件。俗话说，不管白猫黑猫，捉住老鼠才是好猫。会捉老鼠的猫是不大叫的。当它发现鼠踪，立刻伏下，耐心等待出击时机。当老鼠靠近时，就以迅雷不及掩耳之势猛扑上去，一下子把老鼠咬住。 猫还有随身携带的探测器--胡须。别小看猫的漂亮胡须，很灵敏，一般等于自身胸围的最大长度，所以，猫是否能深入洞穴，只要胡须量一量洞口就知道。 猫还有一个绝招：骨头软，能在半空自觉翻身，所以，即使它在高楼失足，也摔不死，总是四足先落地，晃晃脑袋，耸耸身子，舔舔脚掌，伸个懒腰，又若无其事地踱开了方步。 猫是老鼠的天敌，之所以有高强的捕鼠本领。首先是因为有一双特殊的眼睛，瞳孔能随光线的强弱而收缩或放大。在强光下瞳孔缩成一道细缝；黑暗里，眼睛睁得又大又圆，即使是伸手不见五指的黑夜，也能清楚地看到东西，再狡猾的老鼠也难逃脱。 它的耳朵很灵活，能随意转向声音的来处，哪怕是极细微的声音，也能及时辨出。 最惹人喜爱的，就是脱奶以后的“童猫”。它们极不安分，好奇心特别强。你瞧，一团毛绒朝小猫滚过来，它大概以为是个“怪物”，倏地一跳，躲得远远的，毛绒团停住了。 小猫趴下死死盯着，好一会儿，见线团没有动静，就悄悄地移步向前，“咪呜--”叫了一声。线团还是一动不动。这时候，小猫再也耐不住，壮着胆子靠拢线团，围着转了几圈，而后伸出前爪小心翼翼地碰了碰。当它明白线团并不存在危险时，便毫无顾忌地玩起来，一会儿用鼻子嗅嗅，一会儿叼着“胜利品”，在院子里跑来跑去。 像母鸡生了鸡蛋会“咯咯”叫那样，逮住老鼠的猫会发出“呜----”的叫声，表示快乐，显示胜利。猫，应该得到人们保护和宠爱。
多看课外书就知道怎样写
1， experimental animal breeding: experimental animal breeding research experimental animal genetic improvement and genetic control， and wild animals and livestock of experimental 2， experimental animal medicine: experimental animal medicine specialized experimental animal diseases diagnosis， treatment， prevention and it how in biomedical application 3 and comparative medical: comparative study of all animals， including man the similarities and differences between the basic life 4， experimental animal ecology: experimental animal living environment and conditions， such as animals houses， animal facilities， ventilation， temperature， humidity， light and noise， cage with， feed， water and various mat 5， animal experiment technology: the study of animal experiments various operating technology and experimental methods， including experimental animal raising management technology and itself of various monitoring technology，
实验动物相关论文题目有哪些英语作文
When farmers kill a large number of eagles， for example， each animal has a place in the natural Fortunately， animals need to be Animals are natural Over the course of our history， people have been wasting these In the United States， these species are considered in danger because there are no eagles to control their numbers， and because once they are dead， why should people care about movement? Thousands of species of animals have disappeared from the earth and destroyed forever One animal can cause many Animals are not only beautiful and interesting corn and grains destroyed by mice and Mice and mice breed There will never be so many countries passing Why， farmers because Eagles eat mice and mice? Some groups raise money to let people know that these laws prohibit killing any animal or plant on the dangerous list， Some people are trying to help save animals， and just because they are hindering the growth of endangered animals， because we need animals， and today hundreds of animals are on the danger They are not just sources of Animals are killed for their fur and They are trying to get the government to protect animals in danger by law for food :中文翻译：当农民杀死大量的鹰，例如每一种动物都在自然平衡中占有一席之地。幸运的是，动物需要保护动物是自然资源，在我们的历史长河中，人们一直在浪费这些资源，而在美国，这些物种被认为处于危险之中，因为没有老鹰来控制它们的数量，而且因为一旦它们死了，人们为什么要关心运动成千上万种动物已经从地球上消失了永远毁灭一种动物会造成许多问题动物不仅仅是美丽有趣的玉米和谷物被老鼠和老鼠破坏了，老鼠和老鼠繁殖很快，再也不会有那么多国家通过了法律为什么，农民们因为鹰吃老鼠和老鼠一些团体筹集资金让人们知道这些法律禁止杀死危险名单上的任何动物或植物的问题，一些人正在努力帮助拯救动物，并且仅仅是因为它们阻碍了濒危动物数量的增长，因为我们需要动物，今天还有数百种动物被列入了危险名单，它们不仅仅是食物的来源动物被杀是为了它们的皮毛和羽毛，它们试图让政府通过法律保护处于危险中的动物，为了食物。
为什么需要动物研究英语作文可以写为了探索大自然的奥秘，为了扩大人类的视野，为了增长智慧，为了发明创造，有时应当把动物当做老师。比如雷达的发明，就是在研究蝙蝠的基础上一步步创造出来的。潜水艇是在研究鱼为什么会沉入水中、又为什么浮到水面的基础上创造出来的。过去一个多世纪，医学和生命科学取得了飞跃式的发展，人类不仅建立了麻醉、安全输血、器官移植、人工心脏瓣膜等医疗技术和手段，还研发出了抗生素、疫苗和各种药物，从而消灭或控制了多种疾病，所有这些成就的取得都离不开动物实验的支持。动物实验的意义很多介入性的实验无法在人类身上进行，而诸如小鼠、大鼠、兔、猪、猫、狗和猴等实验动物不仅在遗传组成上与人类高度同源，而且具有和人类相似的器官和系统，并以大致相同的方式完成其生理功能，同时还会患与人类疾病类似的各种疾病。因此科学家可以通过动物实验来模拟人类的生理活动及疾病发生和发展的过程。以诺贝尔生理或医学奖为例，截止到今年，在219位获奖者中，有183位的工作与动物实验相关。比如本公众号前面介绍过的德国科学家冯贝林基于豚鼠实验，建立了白喉毒素抗血清和抗血清疗法，并因此获得了首届诺贝尔生理或医学奖豚鼠-早期感染实验的明星动物。
1， experimental animal breeding: experimental animal breeding research experimental animal genetic improvement and genetic control， and wild animals and livestock of experimental 2， experimental animal medicine: experimental animal medicine specialized experimental animal diseases diagnosis， treatment， prevention and it how in biomedical application 3 and comparative medical: comparative study of all animals， including man the similarities and differences between the basic life 4， experimental animal ecology: experimental animal living environment and conditions， such as animals houses， animal facilities， ventilation， temperature， humidity， light and noise， cage with， feed， water and various mat 5， animal experiment technology: the study of animal experiments various operating technology and experimental methods， including experimental animal raising management technology and itself of various monitoring technology，
Should animal experimentation be continued? As we all know， it’s vexed that whether the animal experimentation should be continued for so long It’s difficult to answer who is The both sides have their own The side who think the animal experimentation should be continued considers it right by reason that the development of science should connect with the experimentation tightly and it’s necessary to use the animals， otherwise the experimentation couldn’t be carried through and the scientists won’t get the They said it’s useless and unvalued to the experimentation without the The other side thinks the people have no right to abuse any The animals in the experimentation are often suffering and the experimentation will shorten their life more or The man is stronger than the animals in But it doesn’t mean that the man has the right to trample on the other 原创，算是抛砖引玉，你再扩充吧
实验动物相关论文题目大全英文翻译
It is now mid-July， the village this evening in celebration of National D Children leaping around the bonfire of joy， when the sounds of the drum with each fireworks off alone in a dark corner， listening to the field of festival concerts， field programs than the programs staged in the village square is more The night was late night 9:00， the weather is cooler， the cicada is no longer It during the day and sing all day， evening fell， the rest， but the rest is often In the thick foliage of the plane trees， suddenly issued a whine like a short， sharp This is the desperate wail of cicadas in a quiet rest， night fanatical hunter green Grasshopper caught Let's stay away from the hustle and bustle to listen， and went to When caught cicadas are still struggling， the Indus trees on the program is still in progress， but the chorus has changed Now turn night artists Sensitive ears can hear the green leaves of the law of the jungle around at the Grasshopper in a whisper to That sound like a pulley， which was very interesting， vague rustling like dry wrinkled Mute and continuous bass， from time to time issued by a burst of very sharp and rapid， near-metal collision crisp sound， this is the katydid's song and music section， and the rest is the While singing the bass have been strengthened， the concert anyway， or humble， very Although in my ear， there are a dozen Grasshopper concert， but their voice is not strong， my ear's tympanic membrane is not able to capture a weak The Shino frogs and other insects is being produced， however， I can hear a little song is very soft and quiet atmosphere in the vast night， Green Grasshopper， if you pull the piano and then a loud a little bit， then you are even better than the cicada In northern China， it allows the cicada usurp your reputation! In June， I caught many male and female grasshopper in a metal This insect is very beautiful， covered with verdant side there are two pale white ribbon， tall and beautiful， slim shapely light， such as yarn， two large About food， I met the same trouble feeding I'll give them lettuce leaves， they eat a little， but do not I have to find another food， they are probably to be fresh meat， but what what is it? Morning， I walk in front of the Indus suddenly next to a tree behind what， at the same time there is a shrill squeak， I ran， it was a Grasshopper is pecking the belly of the cicadas in the I understand that the battle occurred in the morning cicadas still rest in the Unfortunately cicada alive bites， suddenly hop， the attackers and the attackers one fell down from the Sometimes I even see the Grasshopper is very brave to jump to hunt for cicada， cicada is in consternation flew Like an eagle in the sky in pursuit of the But this looting living birds than insects poor， it is weaker than it offensive things， and the Grasshopper on the contrary， it is offensive is much greater than their own， sturdy and much more animals， and this body size between the melee， the result is no Grasshopper has a strong jaw and sharp pliers， not captives disembowelling very rare， because cicada no weapon to refute， can only whine Green Grasshopper (3) the food of my cage prisoners to find， I use cicadas to feed Dish to eat with relish， so that the rest of the skull and sternum during the two or three stars， this cage full of cicadas meat was eaten， ripped off the wings and mutilation Stomach to be eaten whole， this is a good site， although not much meat， but it seems to taste especially Because in this location， in the crop， the accumulation of the cicada with its beak to suck from the tender branches to take the syrup sweet Because of this sweets cicadas in the stomach than other parts of the more popular? Very likely it will In order to transform the pattern of the food， I returned to Grasshopper eat the sweet fruit: a few slices of pears， a few grapes， a few pieces of They liked to Englishman loves to eat jam for condiments， bloody steak， green grasshopper fond of Maybe this is the first catch cicadas eat the reasons of the stomach， because both the belly meat， there are Is not anywhere to eat the cicada meat stick sugar， so something else to Scarab insects， it did not hesitate to accept， eat wings， head and claws What all this means katydid like to eat insects， especially insects， is not too hard armor It is very fond of meat， unlike mantis only eat Grasshopper this cicada the butcher in the meat and drink blood after eating the sweet pulp of the fruit， sometimes there is no good， and even eat a little Grasshopper also exists the phenomenon of Indeed， in my cage， I have never seen like a praying mantis killing and sisters， to devour her husband's brutality， but if a Grasshopper was dead， the living will not let the opportunity to taste his body， it like to eat a normal This is not because of lack of food， but because of greed only eat dead Putting that point aside， Grasshopper is very harmonious to each other and co-residence with the never quarrel between them at best to face the food a bit hostile I threw them into a pear， a Grasshopper immediately occupy Who bite a piece of delicious food， out of jealousy， it will kick the other Selfishness is everywhere Full， it will give way to another Grasshopper， then it is very One after another， all Grasshopper product to a After the crop is full， the beak tip scratched the soles of the feet and wiped his face and eyes stained saliva claws， and then his eyes closed or lying on the sand in the digestion of Most of the day to rest， especially in hot
1， experimental animal breeding: experimental animal breeding research experimental animal genetic improvement and genetic control， and wild animals and livestock of experimental 2， experimental animal medicine: experimental animal medicine specialized experimental animal diseases diagnosis， treatment， prevention and it how in biomedical application 3 and comparative medical: comparative study of all animals， including man the similarities and differences between the basic life 4， experimental animal ecology: experimental animal living environment and conditions， such as animals houses， animal facilities， ventilation， temperature， humidity， light and noise， cage with， feed， water and various mat 5， animal experiment technology: the study of animal experiments various operating technology and experimental methods， including experimental animal raising management technology and itself of various monitoring technology，
Congenital kidney maldevelopment and molecular biology research The abstract kidney maldevelopment is the kidney has theunusual clinical consequence， its typical histo-pathologycharacteristic is appears originally Beginning kidney pellet and 肾小管， 软骨样 metaplasia andso In recent years through application molecular technology and soon target gene and home position clone Has the molecular regulation mechanism research to the normalmammal kidney， has to the congenital kidney maldevelopmentpathogenesis More This article will make a discussion to thecongenital kidney maldevelopment molecular biology research recentsituation， and will be right Including the growth factor several kind of gene mutation，copies the regulative barrier and the expression change and the kidneysends the good relations Carries on the The kidney maldevelopment is the kidney has not been able to carry onthe congenital disease which the normal growth growth forms， in thepast arose to it The mechanism understanding are really few， along with themember biological technology development and the application， expoundsthe kidney occurrence from the member study mechanism Had a more thorough understanding from the molecular biologylevel to the kidney maldevelopment This article onshort-term regarding this question The research progress makes an 1 kidney occurs with the kidney maldevelopment Before the normal mammalia kidney is located between liesbetween 中胚层， 中胚层 the differentiation forms the kidneydrive pipe， after further tempts Leads forms 中肾 the drive pipe to the ureter bud， under theureter bud induction， end the embrionic body two sides fresh reninssplits up into after The kidney 胚基， the kidney embryonic development isprecisely completes by the ureter bud and the latter kidney 胚基 twoparts， former gradually grows Becomes 肾盂， 肾盏 and 集合管， latter grows肾小管and the kidney pellet， finally 肾小管and集合管docking， Constitutes normally 肾单位 If the ureter bud and thelatter kidney 胚基 two parts cannot grow according to the normaldegree and implement rightly Meets namely creates the kidney The kidneymaldevelopment may be partial， also may be Most types The kidney maldevelopment partner has the cyst， prompts themaldevelopment each kind of form to have machine-made together in On clinical common congenital kidney maldevelopment including multi-pouches， obstruction kidney maldevelopment as well as with gene The related kidney growth is The histo-pathologyimportant characteristic appears primitive 肾小管and the Complete list The side kidney maldevelopment， may display for does not havethe In most maldevelopment case of illness， the kidney flawis the double side， prompts Gene mutation in normal kidney growth vital Shan Cexingdisease then possibly is one kind of obtaining damage is the resultof， This damage destroyed the gene normal expression， thenaffected maturely had the vital significance to the kidney the 2 kidneys maldevelopment common type 1 congenital multi- pouches kidneys maldevelopment The multi- pouches kidney maldevelopment (multiple cystichypoplastic) is one common completeness The kidney maldevelopment， are many for the single sidepathological change (14-20% for double side nature)， contracts thekidney to lose the normal shape， irregular The size cyst replaces， the kidney function loses and oftenthe partner has the ureter obstruction， is newborn abdomen Bao Kuaizuicommon One of The multi- pouches maldevelopment kidney outlook assumes thekidney-shaped structure， the most case of illness partner has a 闭锁 Pregnancy The early polycystic kidney includes the normal growth to havethe ingredient， loses the urine including the induction after kidney胚基 island and the branch The tube drive pipe， may distinguish the pouch change in thisstage 肾单位 each Duan Yijun [ 1 ] After lives the multi- pouchesmaldevelopment kidney The histo-pathology variation including the primitive肾小管pouch change， expands also the disarrangement of thestructure， has around the obvious tube Response nature， textile fiber myo- link formation， cartilageingredient as symbol organization transformation and so 2 congenital obstructions kidneys maldevelopment The congenital urine road obstruction in dissects in theposition often to occur to the ureter and urinary bladder 连接处，after congenitalness The urethra valve is the babies and infants uninary systemobstruction important Congenital obstruction kidney histologycharacteristic and multi- pouches The kidney maldevelopment is similar， including 肾单位 eachDuan Rushen the pellet pouch transformation， the nature expands alsothe disarrangement of the structure， the marrow The nature and the straight small blood vessel remarkablehypoplasia， has around the tube the textile fiber myo- link， the manykinds of forms kidney pellet and the growth kidney Unit each Is same with the multi- pouches kidneymaldevelopment， the congenital obstruction kidney performance is aseries of diseases， its degree and The embryonic period urine 流阻 related fills the time whichoccurs [ 2 ] The table partner has the kidney to grow the unusual syndrome ------------------------------------------------------ Syndrome chromosome heredity form ------------------------------------------------------ The tip and refers to (foot) to be abnormal (Apert ' s)常染色体 the dominance Sends chest gallery malnutrition 常染色体 recessivenesswhich suffocates Obese， reproduction hypofunction and so on 常染色体recessiveness Gill - ear - kidney 常染色体 dominance Campomelic growth exceptionally 常染色体 recessiveness Brain - liver - kidney (Passarge ' s) 常染色体recessiveness Fryns ' s 常染色体 recessiveness Goemine ' s X- connection Goldston (hereditary blood capillary expands) 常染色体recessiveness? Hall-Pallster ' s sending out Ivemark ' s 常染色体 recessiveness Marden-Walker ' s 常染色体 recessiveness Mecket-Gruber 常染色体 recessiveness Miranda ' s 常染色体 recessiveness Senlor-Loken ' s 常染色体 recessiveness? Three bodies chromosomes 16-18 (Edwards) Three bodies chromosomes 13-15 (Patau) Three bodies chromosomes 21 (Down) 结节性 hardened 常染色体 dominance Von Hippel-Lindau 常染色体 dominance ------------------------------------------------------ 3 kidneys maldevelopment syndrome The kidney maldevelopment syndrome is includes kidney abnormalthe and so on pouch maldevelopment hereditary indication group (seesthe table ) Presently expounds a part of syndromes its special gene andthe protein The maldevelopment phenotype apparent rate assumes Presently a band， prompts has other gene influence kidneysfinally 表型 The maldevelopment usually all contains the many kindsof organs， Explained the flaw the gene involves the normal organogenesisthe The histo-pathology discovered that， this kind ofsyndrome light is possible Appears the great pouch to form (for example 结节性hardening)， heavy possibly appears the pouch growth exceptionally withthe renal failure (Meckel- Gruber syndrome) 3 kidneys maldevelopment molecular biology The present research discovery has the many kinds of genes andthe kidney maldevelopment related， like WT-1， Pax-2， GDNF， B Gene and so on F-2， BMP-7， PDGF， Wnt-4 in after kidney 胚基 Pax-2， c-ret， BMP-7， alpha 3 beta 1 and so on in ureter bud When these genes lack ordestroys， the kidney cannot normally occur with the growth [ 3 ] Sonnenberg and so on [ 4 ] 补体 RNA and the DNA probeconducts the research with the specificity immune body and theemission mark， the determination Multi- peptides growth factor， heparin structure growth factorand their acceptor， extracellular matrix member and cell surfaceentire Gathers gene and so on element in the kidney growth specificexpression For example liver cell growth factor mainly inafter kidney embryo gene Expression， but its acceptor c-met in ureter plumule This kind of peptides and its the acceptor are thin in twokind of types On butcher's expression explanation ureter drive pipe formsthe induction to the after 肾间 archery Schuchardt and so on[ 5 ] passes Using the gene recombination and the preparation 纯合子invalid sudden change mouse， discovers some influence kidney growththe gene and the multi- peptides， like The shift growth factor - beta， the liver cell growth factor，the insulin type growth factor - II， according to saw finally shows The inference specific gene has the function in the Tyrosine activating enzyme body acceptor c-ret leads in thebranch ureter The tube as well as matches in the nerve nutrition factorwhich the body - neuroglia grows to When the mouse c-ret geneis destroyed， leads Sends the entire kidney Copies the factor genecode protein to be able with the DNA union， moreover has regulatesother gene tables Reaches In the mammal kidney growth， Wilms ' tumorgene WT-1 and Pax2 code copies the factor， Its expression form influence kidney cell differentiation [ 6，7 ] The gene syndrome and the kidney form exceptionally related， inthe table arranges in order Leaves the disease， some syndromes have the heredity， somewhathas located the specific gene flaw with the home position clonetechnology [ 8 ] These syndromes are being sick the family members to beable to have the remarkable 表型 This kind of situationand in 纯合子 is invalid The sudden change mouse sees the variation is similar， namelythe kidney finally 表型 is decided by the experimental mouse's The kidney maldevelopment occurrence is several kind of differentgenes flaws， perhaps meets in the embryo development period sends 畸the factor And so on many kinds of genes regulation barrier 肾间 the nature - epidermis transforms process as well asureter branch and growth Is complex and the huge gene system guides by， some genes arethe kidney specificity， some rights and wrongs are special Certain growth factor genes， although they have the timeexpression in the kidney to be active， but when they are destroyedcertainly not shade The loud kidney normal growth， this meant the growth kidneynormal expression each kind of gene has in the function overlaps [ 9] Another one Plants the possibility is this kind of normal expression formdestruction in the kidney maldevelopment occurrence development thecertain function， or Is the kidney maldevelopment The latter 肾间 nature flaw may cause the kidney Moreover， the gene ill should is the dislocation expression， possiblyto kidney The maldevelopment plays the certain On clinical hasthe isolation the multi- pouches kidney maldevelopment and theobstruction kidney maldevelopment two Parallel existence case of Congenitalness and theexperimental nature single gene mutation may cause the pouch kidneygrowth to be unusual， these genes The sudden change may change mutually Theoreticallyspeaking， the sudden change may affect: (1) 胚基 proliferation andsplit up ureter drive pipe minute An institute must peptide and matrix protein expression; (2)Ureter drive pipe to after kidney 胚基 signal reaction capacity; (3)Loses After the ureter drive pipe expression starts and maintainsthe kidney 胚基 epidermis induction to need the protein the ability;(4) Latter kidney 胚基 to these letters The number carries on the response the ability; (5) Ureterbud and latter kidney 胚基 cell to signal reaction capacity [ 10 ] Recently already separated the phosphoric acid glucose phaseomanniteglycoprotein gene， was called the GPC3 The GPC3 flaw and aremany Pouch kidney maldevelopment related [ 11 ] Although thesingle gene may finally cause the kidney maldevelopment with themulti- genes flaw， but Its 表型 possibly decided to receives the gene regulationwhich affects to be out of balance or the expression change at first，like congenital obstruction and pouch Kidney maldevelopment [ 12， 13 ] The multi- pouchesmaldevelopment kidney， and in the nature has the growth factor gene inthe pouch epidermis C In the mouse obstruction growth kidney， the bloodvessel tense element and the shift growth factor assumes excessivelyexpresses [ 14 ] Grinds Investigates the proof， in the after kidney growth unusualarea， promotes the acorn tube epidermis to appear the pouch changefactor Pax2 and Bcl-2 same Assumes excessively expresses [ 15， 16 ] This researchpossibly can provide the important line to each kind of form kidneymaldevelopment pathogenesis R 先天性肾发育不良与分子生物学的研究 摘要 肾发育不良是肾发生异常的临床后果，其典型病理组织学特征是出现原始肾小球和肾小管、软骨样化生等。近年来通过应用靶基因和原位克隆等分子技术对正常哺乳动物肾脏发生分子调控机制的研究，对先天性肾发育不良的发病机理有了更多的了解。本文将对先天性肾发育不良的分子生物学研究近况作一讨论，并对包括生长因子在内的几种基因突变、转录调控障碍及表达变化与肾发良不良的关系进行探讨。 肾发育不良是肾脏未能进行正常生长发育形成的先天性疾病，过去对其发病机理了解甚少，随着分子生物技术的发展和应用，从分子学机理来阐明肾脏的发生，从分子生物学水平对肾发育不良的发生有了较深入的认识。本文就近期对此问题的研究进展作一介绍。1 肾发生与肾发育不良 正常哺乳类肾脏位于间介中胚层，中胚层分化形成前肾导管，经进一步诱导形成中肾导管至输尿管芽，在输尿管芽诱导下，胚体尾端两侧的生肾素分化为后肾胚基，肾脏的胚胎发育正是由输尿管芽和后肾胚基二部分完成的，前者逐步发育成肾盂、肾盏和集合管，后者发育成肾小管和肾小球，最后肾小管和集合管对接，构成正常的肾单位。如果输尿管芽和后肾胚基二部分不能按正常程度发育和实行对接即造成肾发育不良。肾发育不良可以是部分性的，也可以是完全性的。多数类型的肾发育不良伴有囊肿，提示发育不良的各种形式在形成中有共同机制。 临床上常见的先天性肾发育不良包括多囊性、梗阻性肾发育不良以及与基因有关的肾发育异常。病理组织学重要特征是出现原始肾小管和化生软骨。完全性单侧肾发育不良，可表现为无症状。多数发育不良病例中，肾缺陷是双侧性的，提示基因突变在正常肾发育中起重要作用。单侧性疾病则可能是一种获得性损伤所致，该损伤破坏了基因的正常表达，进而影响了对肾成熟有重要意义的蛋白质的产生。2 肾发育不良常见类型1 先天多囊性肾发育不良 多囊性肾发育不良（multiple cystic hypoplastic）是一种常见的完全性肾发育不良，多为单侧病变（14-20%为双侧性），患肾失去正常形态，被不规则的大小囊肿所代替，肾脏功能丧失并常伴有输尿管梗阻，是新生儿腹部包块最常见的原因之一。 多囊性发育不良肾外型呈肾形结构，多数病例伴有一个闭锁的输尿管。妊娠早期的多囊肾含有正常发育所必须的成份，包括未诱导的后肾胚基岛和分支的输尿管导管，在此阶段肾单位各段已均可鉴别出囊性改变[1]。生后多囊性发育不良肾的病理组织学变异包括原始肾小管的囊性改变、膨大且结构破坏、具有明显管周围反应的间质、纤维肌环的形成、软骨成分为标志的组织转化等。2 先天梗阻性肾发育不良 先天性尿路梗阻在解剖位置上常发生于输尿管和膀胱的连接处，先天性后尿道瓣膜是婴幼儿泌尿系统梗阻的重要原因。先天梗阻性肾的组织学特征与多囊性肾发育不良相似，包括肾单位各段如肾小球的囊性转化、间质膨大且结构破坏、髓质和直小血管显著发育不全、发生管周围纤维肌环、多种形式的肾小球和发育的肾单位各段。与多囊性肾发育不良一样，先天梗阻性肾表现为一系列疾病，其程度与胚胎期尿流阻塞发生的时间有关[2]。表 伴有肾发育异常的综合症------------------------------------------------------综合症 染色体遗传形式------------------------------------------------------尖头并指（趾）畸形（Apert’s） 常染色体显性 致窒息的胸廓营养不良 常染色体隐性 肥胖、生殖机能减退等 常染色体隐性 鳃-耳-肾 常染色体显性 Campomelic发育异常 常染色体隐性 脑-肝-肾（Passarge’s） 常染色体隐性 Fryns’s 常染色体隐性 Goemine’s X-连接的 Goldston(遗传性毛细血管扩张) 常染色体隐性？ Hall-Pallster’s 散发的 Ivemark’s 常染色体隐性 Marden-Walker’s 常染色体隐性 Mecket-Gruber 常染色体隐性 Miranda’s 常染色体隐性 Senlor-Loken’s 常染色体隐性？ 三体染色体16-18（Edwards） 三体染色体13-15（Patau） 三体染色体21（Down） 结节性硬化 常染色体显性 Von Hippel-Lindau 常染色体显性------------------------------------------------------ 3 肾发育不良综合症 肾发育不良综合症是包括囊性发育不良等肾畸形在内的遗传性征候群（见表）。现阐明一部分综合症其特异的基因和蛋白质缺陷。发育不良表现型的外显率呈现一个谱带，提示有其他基因影响肾的最终表型。发育不良通常都包含多种器官，说明缺陷的基因涉及正常器官发生的基础。病理组织学发现，此类综合症轻者可能出现巨囊形成（如结节性硬化），重者可能出现囊性发育异常和肾衰竭（Meckel-Gruber综合症）。3 肾发育不良分子生物学 目前的研究发现有多种基因与肾发育不良有关，如WT-1、Pax-2、GDNF、BF-2、BMP-7、PDGF、Wnt-4等基因在后肾胚基表达。Pax-2、c-ret、BMP-7、α3β1等在输尿管芽表达。当这些基因缺乏或被破坏时，肾脏不能正常地发生与发育[3]。Sonnenberg等[4]用特异性抗体与放射标记的补体RNA和DNA探针进行研究，确定了多肽生长因子、肝素结构生长因子及它们的受体、细胞外基质分子和细胞表面整合素等基因在肾发育中的特定表达位置。例如肝细胞生长因子主要在后肾胚基因内表达，而其受体c-met则在输尿管胚芽上皮表达。这种多肽及其受体在两种类型细胞上的表达说明输尿管导管对后肾间质的形成起诱导作用。Schuchardt等[5]通过应用基因重组与制备纯合子无效突变小鼠，发现一些影响肾发育的基因和多肽，如转移生长因子-β、肝细胞生长因子、胰岛素样生长因子-Ⅱ，根据所见到的最终表型推断特定基因在正常肾发生中的作用。酪氨酸激酶体受体c-ret在分支输尿管导管以及配体-神经胶质衍生的神经营养因子上表达。当小鼠c-ret基因被破坏时，导致全肾发育不良。转录因子基因编码蛋白能与DNA结合，而且具备调控其它基因表达的功能。在哺乳动物肾发育中，Wilms’肿瘤基因WT-1及Pax2均编码转录因子，其表达形式影响肾细胞的分化[6，7]。基因性综合症与肾形成异常有关，表中所列出的疾病，有些综合症有遗传性，有些用原位克隆技术已定位出特定的基因缺陷[8]。这些综合症在患病家族成员能发生显著的表型变异。这种情况与在纯合子无效突变小鼠所见的变异相似，即肾的最终表型取决于实验小鼠的基因背景。 肾发育不良的发生是几种不同的基因缺陷，或是在胚胎发育期遇到致畸因子等多种基因调控障碍的最终结果。肾间质-上皮转化的过程以及输尿管分支和生长，是由一个复杂而庞大的基因体系来导向，有些基因是肾特异性的，有些是非特异的。某些生长因子基因，尽管它们在肾发生期表达活跃，但当它们被破坏时并不影响肾的正常发育，这意味着发育肾正常表达的各种基因在功能上有重叠[9]。另一种可能性是这种正常表达形式的破坏在肾发育不良的发生发展中起一定作用，或者就是肾发育不良的起因。 后肾间质缺陷可导致肾发育不良。另外，基因不适应和错位表达，可能对肾发育不良起一定作用。临床上有孤立的多囊性肾发育不良和梗阻性肾发育不良两者并行存在的病例。先天性和实验性单基因突变均可导致囊性肾发育异常，这些基因突变可改变相互联系。从理论上讲，突变可影响：①胚基增生和分化输尿管导管分支所必需的肽和基质蛋白的表达；②输尿管导管对后肾胚基信号的反应能力；③输尿管导管表达启动和维持后肾胚基上皮诱导所需蛋白的能力；④后肾胚基对这些信号进行反应的能力；⑤输尿管芽和后肾胚基细胞对信号的反应能力[10]。 最近已经分离出磷酸葡萄糖肌醇糖蛋白基因，简称GPC3基因。GPC3缺失与多囊性肾发育不良有关[11]。虽然单基因与多基因缺陷均可最终导致肾发育不良，但其表型可能决定于最初受影响的基因调控失调或表达改变，如先天性梗阻性和囊性肾发育不良[12，13]。多囊性发育不良肾，在囊性上皮和间质中均有生长因子基因的改变。在小鼠梗阻性发育肾中，血管紧张素和转移生长因子呈过度表达[14]。研究证明，在后肾发育异常区，促进小管上皮出现囊性改变的因子Pax2和Bcl-2同样呈过度表达[15，16]。此研究可能会对各种形式肾发育不良的发病机制提供重要线索。