首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
小尾寒羊高繁殖力候选基因RBP4的研究   总被引:6,自引:0,他引:6  
以视黄醇结合蛋白4(retinol binding protein 4,RBP4)基因为候选基因,采用PCR-SSCP技术分析了RBP4基因在高繁殖力绵羊品种(小尾寒羊、湖羊)以及低繁殖力绵羊品种(多赛特羊、萨福克羊)中的单核苷酸多态性,同时研究这个基因对小尾寒羊高繁殖力的影响。结果表明:RBP4基因扩增片段在4个绵羊品种中存在PCR-SSCP多态性。BB基因型只出现在高繁殖力绵羊品种中,而低繁殖力绵羊品种则没有BB基因型;AB基因型频率随着绵羊繁殖力的降低而升高;AA基因型只出现在小尾寒羊、多赛特羊中。BB基因型小尾寒羊产羔数分别比AA和AB基因型多0.52只(Pd0.05)和0.67只(Pd0.05),AA和AB基因型小尾寒羊产羔数没有显著差异(P〉0.05)。本研究检测的绵羊RBP4基因座位与小尾寒羊高繁殖力相关。  相似文献   

2.
绵羊MyoG基因外显子的单核苷酸多态性群体遗传学分析   总被引:1,自引:0,他引:1  
采用PCR—SSCP技术分析了肌细胞生成素(MyoG)基因外显子1、2在蒙古羊、无角陶赛特羊、德国肉用美利奴羊和白萨福克羊这4个绵羊品种的多态性。结果表明在在外显子1(exonⅠ)所扩增的片段中存在3种基因型(AA型、AB型和BB型),在外显子2(exonⅡ)所扩增的片段中不存在多态性。对于exonⅠ扩增片段,4个绵羊品种均检测到AA和AB基因型;BB基因型只在蒙古羊、陶赛特羊和白萨福克羊中检测到。在4个绵羊品种中,蒙古羊的AA基因型频率最高,而其它3个品种羊是AB基因型频率高;A等位基因频率明显高于B等位基因频率。exonⅠ的多态性片段测序分析表明:MyoG基因第305处发生了单碱基突变(T→C),并导致了所编码氨基酸由半胱氨酸变为精氨酸。  相似文献   

3.
小尾寒羊高繁殖力候选基因RARG的研究   总被引:8,自引:0,他引:8  
以视黄酸受体γ(retinoic acid receptor-gamma,RARG)基因为候选基因,采用PCR—SSCP技术分析了RARG基因在高繁殖力绵羊品种(小尾寒羊、湖羊)以及低繁殖力绵羊品种(特克塞尔、多赛特、萨福克)中的单核苷酸多态性,同时研究这个基因对小尾寒羊高繁殖力的影响。结果表明:RARG基因引物1扩增片段在5个绵羊品种中存在PCR—SSCP多态性,AA基因型只出现在湖羊中,AB和BB基因型均出现在5个绵羊品种中;BB基因型小尾寒羊平均产羔数比AB基因型多0.41只,但差异不显著(P〉0.05)。RARG基因引物2扩增片段在5个绵羊品种中存在PCR—SSCP多态性,CC和CD基因型均出现在5个绵羊品种中,5个绵羊品种中都没有检测到DD基因型;CC基因型小尾寒羊平均产羔数比CD基因型多0.55只(P〈0.05)。  相似文献   

4.
绵羊高繁殖力候选基因BMPR-IA的研究   总被引:3,自引:0,他引:3  
以骨形态发生蛋白受体IA(bone morphogenetic protein receptor IA,BMPR-IA)基因为候选基因,采用PCR—SSCP技术检测该基因在高繁殖力绵羊品种(小尾寒羊、湖羊)以及低繁殖力绵羊品种(多赛特羊、特克塞尔羊、德国肉用美利奴羊)中的单核苷酸多态性,同时研究该基因对小尾寒羊高繁殖力的影响。结果表明:在小尾寒羊中检测到AA、AB两种基因型,在湖羊中只检测到一种基因型BB,而在低繁殖力的3个绵羊品种中只检测到一种基因型AA。统计结果表明:小尾寒羊A等位基因频率为0.964,B等位基因频率为0.036。测序结果表明:BB型与AA型相比有6处核苷酸发生了突变。独立性检验表明:外尾寒羊与低繁殖力绵羊品种间基因型分布差异不显著(P〉0.05),而湖羊与小尾寒羊、低繁殖力绵羊品种间基因型分布差异极显著(P〈0.001)。AB基因型小尾寒羊平均产羔数比AA基因型多0.15只,但差异不显著(P〉0.05)。研究表明:BMPR-IA基因不是小尾寒羊和湖羊高繁殖力的主效基因。  相似文献   

5.
为了探究KAP2基因在不同绵羊群体的多态性,本次试验利用PCR-SSCP的方法,分析新吉细毛羊、道赛特羊和小尾寒羊的基因型和突变位点,并对KAP2基因编码区序列进行多态性分析。结果:新吉细毛羊基因序列第292位点处发生T→C的突变,绵羊群体基因型可分为AA、AB、BB基因型;A基因频率中新吉细毛羊、道赛特羊、小尾寒羊分别为0.3261、0.3696、0.5217,B基因频率中新吉细毛羊、道赛特羊、小尾寒羊分别为0.6739、0.6304、0.4783,AA基因型频率新吉细毛羊、道赛特羊、小尾寒羊分别为0.2609、0.3043、0.3913,AB基因型频率新吉细毛羊、道赛特羊、小尾寒羊分别为0.1304、0.2174、0.2609,BB基因型频率新吉细毛羊、道赛特羊、小尾寒羊分别为0.6087、0.4783、0.3478。结论:绵羊群体分为AA、AB、BB基因型,BB基因型为优势基因型。  相似文献   

6.
绵羊MyoG基因外显子1的多态性及其与肉质性状的关联分析   总被引:1,自引:0,他引:1  
肌细胞生成素(myogenin,MyoG)基因在肌细胞分化过程中起着中心调节作用,直接影响着动物的产肉能力。本研究以大尾寒羊、小尾寒羊、豫西脂尾羊、兰州大尾羊、蒙古羊、同羊6个绵羊品种为试验材料,利用非变性聚丙烯酰胺凝胶电泳检测MyoG基因外显子1的多态性,并与绵羊的肉质性状进行关联分析,探讨MyoG基因外显子1对绵羊肉质性状的影响。结果表明,MyoG基因外显子1在6个绵羊群体中均检测到3种基因型(AA、BB、AB)和2个等位基因(A、B),在小尾寒羊、大尾寒羊、豫西脂尾羊、兰州大尾羊、蒙古羊、同羊群体中检测到MyoG基因外显子1的A等位基因频率分别为:0.5167、0.2500、0.4375、0.6500、0.5750和0.7125,MyoG基因外显子1的B等位基因频率分别为:0.4833、0.7500、0.5625、0.3500、0.4250和0.2875。MyoG基因外显子1主要对羊肉的水分和色泽有影响,主要表现为BB基因型水分极显著高于AB基因型(P< 0.01),显著高于AA基因型(P< 0.05);AB基因型的色泽极显著高于BB基因型(P< 0.01),显著高于AA基因型(P< 0.05)。  相似文献   

7.
以骨形态发生蛋白受体IB(BMPR-IB)基因为小尾寒羊及其与波德代羊、白萨福克羊、无角陶赛特羊杂交后代多胎性能的候选基因,采用PCR-SSCP技术检测该基因分别在11个绵羊群体中的单核苷酸多态性,同时研究该基因对小尾寒羊高繁殖力的影响。结果表明:小尾寒羊和低代杂种后代在BMPR-IB基因编码序列第746位碱基处发生了Q249R突变,小尾寒羊AA、AB和BB的基因型频率分别为0.032 3,0.225 8和0.741 9,B等位基因频率为0.854 8,A等位基因频率为0.145 2。小尾寒羊杂种后代群体中B等位基因频率随杂交代数的增加而降低,而A等位基因频率却随杂交代数的增加而增加。因此,BMPR-IB基因是影响小尾寒羊及其低代杂种后代高繁性能的一个主效基因,可以用于对绵羊产羔数的辅助选择,并进行横交固定培育多胎新品系。  相似文献   

8.
本研究采用聚合酶链式反应-单链构象多态性(PCR-SSCP)分析方法检测3个绵羊的促黄体素受体(LHR)基因第11外显子的多态性.结果表明,促黄体素受体(LHR)外显子11在小尾寒羊、大尾寒羊和豫西脂尾羊中存在3种基因型,记为AA、BB和AB.小尾寒羊、大尾寒羊和豫西脂尾羊的AA、BB和AB基因型频率分别为:0.045...  相似文献   

9.
以GHSR基因为候选基因,随机选取滩羊、小尾寒羊和兰州大尾羊3个品种共计1 249个个体为试验材料,利用DNA池测序结合琼脂糖凝胶电泳方法,检测突变多态性,分析其与体重、生长性状的相关性。试验结果表明,在GHSR基因的第一内含子上存在24 bp的插入/缺失突变,3个绵羊品种中均存在AA、AB、BB 3种基因型。该位点的多态性与3种绵羊8个生长性状指标关联分析显示,兰州大尾羊BB基因型的个体体重显著高于其他基因型;AB基因型的个体体高、十字部高显著高于其他基因型;小尾寒羊AB基因型的个体胸宽显著高于其他基因型;AA基因型的个体体高、十字部高显著高于BB基因型;滩羊AB基因型的个体体斜长、体重显著高于AA基因型,BB基因型的个体体高显著低于其他基因型。研究表明:GHSR基因可以作为3种绵羊生长性状的候选基因,为绵羊育种选育提供新思路。  相似文献   

10.
神经肽Y基因多态性及其与小尾寒羊产羔数的关系   总被引:1,自引:0,他引:1  
本研究旨在阐明神经肽Y(neuropeptide Y,NPY)基因的多态性及其与小尾寒羊产羔数的关系,为绵羊多羔性的标记辅助选择提供科学依据.采用PCR-SSCP技术检测NPY基因全部3个外显子在小尾寒羊、湖羊、特克塞尔和多赛特羊中的单核苷酸多态性,分析该基因对小尾寒羊多羔性的影响.仅引物P1扩增片段存在多态性,在小尾寒羊中检测到5种基因型,在湖羊和多赛特羊中检测到3种基因型,而在特克塞尔羊中仅枪测到1种基因型;测序分析显示,在小尾寒羊中存在CR、TR和TW3种等位基因,在湖羊和多赛特羊中存在CR和TR 2种等位基因,而在特克塞尔中仅存在CR 1种等位基因.TR与CR相比在绵羊NPY基因编码区第93 bp处发生了1个C→T的单碱基突变;TW与CR相比除发生C93T的单碱基突变外,还在130和131 bp发生了GA塞AT的双碱基突变,该突变引起绵羊NPY成熟肽第16位氨基酸由天冬氨酸变为异亮氨酸.对于多态位点C/T,小尾寒羊3种基因型之间产羔数差异均不显著(P>0.05).对于多态位点GA/AT,RW型小尾寒羊产羔数平均比RR型的多0.56只(P<0.05).在小尾寒羊5种复合基因型中,TTRW和CTRW型小尾寒羊产羔数差异不显著(P>0.05);TTRR、CTRR和CCRR型小尾寒羊产羔数差异也不显著(P>0.05);TTRW和CTRW型小尾寒羊产羔数均显著高于其余3种基因型(P<0.05).本研究结果初步表明NPY基因GA/AT突变位点的W等位基因是提高绵羊产羔数的1个潜在有效的DNA标记.  相似文献   

11.
试验选用96头平均体重14.82 kg左右的杜×长×大断奶仔猪,随机分成4组,每组3栏,每栏8头(公母各半)。对照组饲喂基础日粮,试验1、2、3组分别添加1%80目白术、0.2%白术多糖和1%微米白术。试验期30 d。结果表明:在生长性能方面,与对照组相比,1%微米白术添加组可显著提高日增重(P0.05)、降低饲料增重比和腹泻率,而且效果优于1%80目白术组和0.2%白术多糖组,在肠道形态和肠道微生态区系方面,与对照组相比,日粮添加1%80目白术、0.2%白术多糖、1%微米白术均可不同程度的提高十二指肠和空肠的绒毛高度,加深十二指肠和空肠的隐窝深度,并且增加肠道微生态区系的多样性,其中以1%微米白术添加组的效果最佳。  相似文献   

12.
Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.  相似文献   

13.
1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.  相似文献   

14.
Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.  相似文献   

15.
Genetic variations in chromosome Y are enabling researchers to identify paternal lineages, which are informative for introgressions and migrations. In this study, the male‐specific region markers, sex‐determining region‐Y (SRY), amelogenin (AMELY) and zinc finger (ZFY) were analysed in seven Turkish native goat breeds, Angora, Kilis, Hair, Honaml?, Norduz, Gürcü and Abaza. A SNP in the ZFY gene defined a new haplotype Y2C. All domestic haplogroups originate from Capra aegagrus, while the finding of Y1A, Y1B, Y2A and Y2C in 32, 4, 126 and 2 Turkish domestic goats, respectively, appears to indicate a predomestic origin of the major haplotypes. The occurrence of four haplotypes in the Hair goat and, in contrast, a frequency of 96% of Y1A in the Kilis breed illustrate that Y‐chromosomal variants have a more breed‐dependent distribution than mitochondrial or autosomal DNA. This probably reflects male founder effects, but a role in adaptation cannot be excluded.  相似文献   

16.
Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.  相似文献   

17.
The purpose of this study was to determine the frequency of different tumor types within a large cohort of cats with intracranial neoplasia and to attempt to correlate signalment, tumor size and location, and survival time for each tumor. Medical records of 160 cats with confirmed intracranial neoplasia evaluated between 1985 and 2001 were reviewed. Parameters evaluated included age, sex, breed, FeLV/FIV status, clinical signs, duration of signs, number of tumors, tumor location(s), imaging results, treatment, survival times, and histopathologic diagnosis. Most of the cats were older (11.3 +/- 3.8 years). Primary tumors accounted for 70.6% of cases. Metastasis and direct extension of secondary tumors accounted for only 5.6 and 3.8% of cases, respectively. Twelve cats (7.5%) had 2 or more discrete tumors of the same type, whereas 16 cats (10.0%) had 2 different types of intracranial tumors. The most common tumor types were meningioma (n = 93, 58.1%), lymphoma (n = 23, 14.4%), pituitary tumors (n = 14, 8.8%), and gliomas (n = 12, 7.5%). The most common neurological signs were altered consciousness (n = 42, 26.2%), circling (n = 36, 22.5%), and seizures (n = 36, 22.5%). Cats without specific neurological signs were common (n = 34, 21.2%). The tumor was considered an incidental finding in 30 (18.8%) cats. In addition to expected relationships (eg, meninges and meningioma, pituitary and pituitary tumors), we found that lesion location was predictive of tumor type with diffuse cerebral or brainstem involvement predictive of lymphoma and third ventricle involvement predictive of meningioma.  相似文献   

18.
The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.  相似文献   

19.
The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.  相似文献   

20.
Infectious diseases have always been a terrible scourge for humans. The appearance of these plagues, as they were called without distinction, was generally connected to various conditions: asters, climatic changes or religious reasons. The concept of contagious, and then infectious, diseases came slowly. Variolation, i.e. transmission of ‘virulent’ matter to induce a natural disease and the immunity against it, was brought from Constantinople to England by Lady Montague, in 1721. This ‘variolation’ technique was also often performed in veterinary medicine against diseases like sheep-pox or pleuropneumonia. As ‘vaccination’ is the term generally accepted for ‘immunisation’, variolation can be the word designating such a technique. The second period of the history of immunisation began, in 1880, with the studies of Pasteur and his collaborators. A great number of bacterial vaccines were developed: dead, live but attenuated or only parts of pathogens. The viruses were produced in animals, then in eggs and at last, in tissue cultures. Second generation vaccines appeared with genetic engineering: recombinant vaccines, vector vaccines, nucleic acids vaccines, and markers vaccines, among others. These novel technologies can permit the development of new ones and improve the quality of the vaccines already existing.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号