共查询到20条相似文献,搜索用时 125 毫秒
1.
2.
重组人γ干扰素摇瓶生产工艺优化 总被引:1,自引:1,他引:0
通过研究不同类型培养基和培养温度、起始pH值等发酵条件对rhIFN-γ产量的影响,初步确认了摇瓶水平发酵各因素的最优条件,优化的发酵条件为发酵起始pH值7.0、培养温度37℃、IPTG诱导浓度1.0mmol/L、菌体生长密度OD600达到1.0时加入IPTG、诱导时间为3h。此时rhIFN-γ产量达到最高水平,从而为rhIFN-γ批量生产奠定了良好的基础。 相似文献
3.
通过研究不同类型培养基和培养温度、起始pH值等发酵条件对IL-15产量的影响,初步确认了摇瓶水平发酵各因素的最优条件。优化的发酵条件为发酵起始pH值7.0、培养温度37℃、乳糖诱导浓度1.5g/L、菌体生长密度OD600达到1.0时加入乳糖、诱导时间4h,此时IL-15产量达到最高水平,从而为IL-15批量生产奠定了良好的基础。 相似文献
4.
对重组表达质粒σNS-pGEX-4T-1 IPTG的诱导浓度、诱导时间和诱导温度等条件进行了试验。当细菌的D600值为0.55~0.65时,IPTG最佳诱导浓度为0.8mmol//L,最佳诱导时间为4h,最适诱导温度为28~37℃,表达的目的蛋白相对分子质量约为66200,约占菌体总量的31.5%~33.3%。37℃及32℃诱导时,目的蛋白σNS主要以包涵体的形式存在;28℃诱导时目的蛋白主要以可溶性的方式表达。利用28℃诱导表达目的蛋白,用谷胱苷肽活化的Sepharose 4B亲和层析柱纯化,测定纯化蛋白的纯度与浓度,并对纯化的蛋白进行Western-blot分析。结果显示,纯化后的目的蛋白纯度达93%,质量浓度为0.91g/L,并能与禽呼肠孤病毒阳性血清发生特异性反应。 相似文献
5.
文章目的是考察麦芽糖诱导木聚糖酶基因在枯草芽孢杆菌WB700中的表达。以麦芽糖为诱导剂,对诱导浓度、诱导时机、诱导温度和麦芽糖的添加方式等主要因素进行了分析比较。当菌体生长至发酵液吸光值OD600达到1.3时加入终浓度为4.5%麦芽糖,37℃,持续诱导10h,木聚糖酶活力达到最高,为56.32U/mL,通过SDS-PAGE检测对比显示:经麦芽糖诱导表达的木聚糖酶比不加麦芽糖诱导的木聚糖酶表达量高,表达效果更明显。结果表明麦芽糖在最佳的诱导条件下,对木聚糖酶的酶活有明显的提高作用。 相似文献
6.
将口蹄疫病毒VP1基因插入原核表达载体pET-28a中,转化至大肠杆菌BL21.用不同的IPTG浓度与不同诱导时间诱导菌株表达VP1蛋向,分析不同IPTG浓度及不同诱导时间对蛋白表达量的影响,以确定最佳表达条件.结果表明,在一定范围内,随IPTG浓度的增高,表达量并不会随之增大;而在菌体对数生长期内,随诱导时间的延长,表达量会随之增大.最后确定当IPTG浓度为3 mmol/L,诱导表达到最长时间9 h时,VP1蛋白表达量最大. 相似文献
7.
将口蹄疫病毒VP1基因插入原核表达载体pET-28a中,转化至大肠杆菌BL21。用不同的IPTG浓度与不同诱导时间诱导菌株表达VP1蛋白,分析不同IPTG浓度及不同诱导时间对蛋白表达量的影响,以确定最佳表达条件。结果表明,在一定范围内,随IPTG浓度的增高,表达量并不会随之增大;而在菌体对数生长期内,随诱导时间的延长,表达量会随之增大。最后确定当IPTG浓度为3 mmol/L,诱导表达到最长时间9 h时,VP1蛋白表达量最大。 相似文献
8.
将蛇毒类凝血酶基因(TLE)亚克隆到原核表达载体pMAL-p2X上,对重组表达质粒鉴定正确后,转化大肠埃希菌BL21进行诱导表达;同时采用不同的OD值、诱导时间I、PTG浓度和诱导温度对尖吻蝮蛇蛇毒类凝血酶基因重组表达质粒pMAL-p2X进行了条件优化。研究发现,不同的诱导时间、IPTG诱导浓度和诱导温度与融合蛋白表达量有很大关系。SDS-PAGE结果显示,当OD值为0.5,IPTG终浓度为0.3 mmol/L,诱导温度为37℃时,诱导3 h后蛋白表达量最高,超出此范围可使表达量显著减少。在优化诱导条件后,融合蛋白的表达量可达全菌总蛋白量的66%。 相似文献
9.
采用限制性核酸内切酶酶切鉴定含α毒素突变基因的重组质粒,同时用SDS-PAGE检测不同条件下α 毒素突变基因的表达情况.经酶切鉴定证实重组质粒pXMCPA02含有α毒素突变基因且基因序列和阅读框架正确.同时以IPTG为诱导剂诱导α 毒素突变基因表达并对其表达条件进行优化.优化表达的结果是:培养基pH7.5,培养温度37 ℃,IPTG浓度0.8 mmol/L,菌体生长密度OD600达到0.8时加入IPTG,诱导时间5 h,此时重组菌株pXMCPA02蛋白表达量为35%.从而实现了α 毒素突变基因的高效表达,为A型产气荚膜梭菌α毒素基因工程菌苗的生产工艺研究提供了可靠的试验数据. 相似文献
10.
采用限制性核酸内切酶酶切鉴定含α毒素突变基因的重组质粒,同时用SDS-PAGE检测不同条件下α毒素突变基因的表达情况。经酶切鉴定证实重组质粒pXMCPA02含有α毒素突变基因且基因序列和阅读框架正确。同时以IPTG为诱导剂诱导α毒素突变基因表达并对其表达条件进行优化。优化表达的结果是:培养基pH7.5,培养温度37℃,IPTG浓度0.8 mmol/L,菌体生长密度OD600达到0.8时加入IPTG,诱导时间5 h,此时重组菌株pXMCPA02蛋白表达量为35%。从而实现了α毒素突变基因的高效表达,为A型产气荚膜梭菌α毒素基因工程菌苗的生产工艺研究提供了可靠的试验数据。 相似文献
11.
12.
魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
13.
14.
本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
15.
REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
16.
17.
18.
19.
以国际标准强毒R株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离MG,并收集感染鸡所产蛋分离MG。结果表明,人工感染48小时后上、下呼吸道及肺已被全面感染,96小时气囊已被感染,120小时输卵管已能分离到MG,卵巢始终分离不到MG。人工感染鸡自144小时便能在其所产蛋中分离出MG。药物治疗能在72小时内消除感染,油乳剂苗则需24天后逐渐降低蛋内MG分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内MG,但以研制的种蛋浸泡剂药浴效果为最好。 相似文献
20.
Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献