EHEC O157:H7志贺样毒素Ⅱ结合亚单位Stx2B的基因克隆、表达与纯化

目的克隆表达肠出血性大肠杆菌(EHEC)O157H7志贺样毒素B亚单位(Shiga liketoxin 2B,Stx2B),并对其初步纯化.方法设计引物采用PCR法自EHEC O157H7基因组扩增志贺样毒素B亚单位的编码基因stx2b,T-A克隆后构建原核表达质粒pET-22b(+)-stx2b,经测序鉴定后转化E.coli BL21(DE3),IPTG诱导表达,以Tricine-PAGE和Western blot分析目的蛋白的表达,并采用固相镍离子亲和层析纯化重组蛋白.结果扩增的stx2b基因约210 bp;原核表达质粒pET-22b(+)-stx2b经酶切和测序鉴定与预期序列一致;并在E.coli BL21(DE3)中得到高效可溶性表达,蛋白表达率约30%;PAGE初步测定目的蛋白的相对分子质量(Mr)约7×103;经固相镍离子亲和层析纯化后,蛋白纯度可达90.1%.结论EHEC O157H7志贺样毒素B亚单位的高效表达与初步纯化,有利于进一步的生物学性质研究.     

EHECO157∶H7志贺样毒素Ⅱ结合亚单位Stx2B的基因克隆、表达与纯化

目的克隆表达肠出血性大肠杆菌(EHEC)O157∶H7志贺样毒素B亚单位(Shiga liketoxin2B,Stx2B),并对其初步纯化。方法设计引物采用PCR法自EHEC O157∶H7基因组扩增志贺样毒素B亚单位的编码基因stx2b,T-A克隆后构建原核表达质粒pET-22b(+)-stx2b,经测序鉴定后转化E.coliBL21(DE3),IPTG诱导表达,以Tricine-PAGE和Western blot分析目的蛋白的表达,并采用固相镍离子亲和层析纯化重组蛋白。结果扩增的stx2b基因约210bp;原核表达质粒pET-22b(+)-stx2b经酶切和测序鉴定与预期序列一致;并在E.coliBL21(DE3)中得到高效可溶性表达,蛋白表达率约30%;PAGE初步测定目的蛋白的相对分子质量(Mr)约7×103;经固相镍离子亲和层析纯化后,蛋白纯度可达90.1%。结论EHEC O157∶H7志贺样毒素B亚单位的高效表达与初步纯化,有利于进一步的生物学性质研究。     

热休克蛋白16.3多克隆抗体的制备

目的大肠杆菌表达Hsp16.3,制备其多克隆抗体。方法设计引物,从H37Rv基因组中扩增出目的片段Hsp16.3,pET28a-Hsp16.3质粒的构建、克隆和表达。对His-Hsp16.3进行诱导、表达和纯化。用纯化好的蛋白免疫新西兰大白兔获得多克隆抗体,用ELISA检测抗血清中多抗的效价,用Western blot法检测多克隆抗体的生物活性。结果重组质粒pET28aHsp16.3在E.coli BL21(DE3)中成功表达,SDS-PAGE结果显示在His-Hsp16.3的相对分子质量(Mr)约为20 000。制备的多克隆抗体效价为1∶800,且特异性较好。结论成功的克隆、表达、纯化出His-Hsp16.3,并且成功制备了抗Hsp16.3多克隆抗体。     

肠出血性大肠杆菌O157∶H7志贺毒素I型A亚基的表达与鉴定

目的表达肠出血性大肠杆菌(EHEC)O157∶H7志贺毒素1型A亚基(Stx1A)重组蛋白并鉴定。方法从EHEC O157∶H7基因组中扩增编码Stx1A的基因,经测序无误后,克隆入表达载体pET-22b(+),转化大肠杆菌BL21(DE3),经诱导、纯化获得目的蛋白Stx1A,并对纯化的目的蛋白进行质谱鉴定。重组的Stx1A蛋白免疫BALB/c小鼠,观察小鼠抗血清与EHEC O157∶H7毒株特异性反应。结果 PCR扩增的Stx1A基因为945 bp,成功构建重组质粒pET22b(+)-Stx1a,重组蛋白在原核细胞中获得高效表达,通过AKTATM-His亲和层析柱获得纯化。质谱分析表明目的蛋白为Stx1A。Western blot显示鼠抗Stx1A血清可与EHEC O157∶H7毒株产生的天然毒素蛋白结合。结论成功克隆了EHEC O157∶H7 Stx1A基因,并获得重组表达,为后续研究奠定基础。     

annexinA2基因片段的克隆、表达、纯化及多克隆抗体的制备

目的:构建人源annexinA2基因片段的原核表达载体,表达并纯化蛋白,制备多克隆抗体.方法:从GenBank(BC093056.1) 中获得人源annexinA2基因的cDNA序列并根据不含信号肽的编码序列设计引物,用PCR的方法扩增编码annexinA2基因部分序列,将其克隆到原核表达载体pET28a(+)中表达annexinA2的蛋白.表达的蛋白产物利用切胶回收的方法纯化,用His抗体进行Western blot 鉴定.用纯化的目的蛋白作为抗原免疫日本大耳白兔,获得annexinA2的抗血清,通过ELISA测定兔多克隆抗体的滴度.在CaSki细胞内采用细胞免疫荧光(CIF)和流式细胞术(FCM)检测内源annexinA2蛋白的表达,用于鉴定制备的多克隆抗体特异性.结果:通过双酶切及测序证实原核表达质粒pET28a(+)-annexinA2构建成功,可在大肠杆菌E.coli BL21(DE3)中诱导高表达,得到相对分子质量约28 000的annexinA2蛋白.纯化的蛋白免疫日本大白兔后,产生特异的高滴度的抗体(ELISA 滴度达 1:640 000).CIF和 FCM 结果显示抗血清与肿瘤细胞表达的annexinA2有高度特异的结合活性.结论:构建了annexinA2的原核表达质粒并获得高纯度的蛋白,免疫动物后,获得了特异、高效价的多克隆抗体,为人源annexinA2蛋白的生物学功能及肿瘤治疗的研究提供了实验基础.     

HPV16型E7重组蛋白的表达及其多克隆抗体的制备

目的制备人乳头瘤病毒(HPV)16型E7原核表达蛋白及其多克隆抗体。方法用PCR方法从宫颈癌组织中扩增HPV16 E7基因,克隆至pET21a(+)载体并构建pET21a(+)/HPV16 E7重组质粒,测序鉴定;将重组质粒转化至大肠杆菌BL21(DE3),经异丙基硫代-β-D-硫代吡喃半乳糖苷(IPTG)诱导后表达重组蛋白,用Ni-NTA亲和层析法纯化并经SDS-PAGE及Western blot分析鉴定;纯化的HPV16 E7重组蛋白免疫日本大耳白兔制备多克隆抗体,用ELISA检测多克隆抗体的效价,并用Western blot法及免疫荧光技术分析多克隆抗体的特异性。结果 HPV16 E7重组蛋白可通过原核表达系统进行表达和纯化;通过兔免疫后可制备特异性的多克隆IgG抗体,效价达1∶30 000;经Western blot法和免疫荧光染色结果证实兔多克隆抗体可特异性识别HPV16 E7蛋白。结论成功进行了HPV16 E7原核表达并制备了HPV16 E7兔多克隆抗体。     

人BTLA分子胞外区的原核表达及其多克隆抗体的制备与鉴定

目的:表达并纯化重组人BTLA(hBTLA)分子胞外区,制备和鉴定兔抗hBTLA多克隆抗体,为进一步实验研究奠定基础。方法:采用特异性引物扩增hBTLA胞外功能区DNA,经酶切、连接构建原核表达载体pET28a-hBTLA。将构建的重组表达质粒转化入E.coliBL21(DE3)菌株,采用IPTG诱导表达,Ni-NTA柱亲和层析纯化目的蛋白,SDS-PAGE电泳分析蛋白纯度。将纯化的目的蛋白免疫家兔制备多克隆抗体,并对抗体进行纯化、效价测定及特异性鉴定。结果:序列测定证实构建的pET28a-hBTLA重组表达载体含有hBTLA编码序列,其序列比对分析与GenBank中公布序列一致,质粒在E.coli中诱导表达相对分子质量(Mr)为15720的目的蛋白,SDS-PAGE电泳分析纯化后的目的蛋白达到电泳纯。双向琼脂扩散法检测抗体效价为1∶16,ELISA法检测抗体效价为1∶20 000,Western blot分析显示抗体能特异性结合重组hBTLA蛋白。结论:成功构建了hBTLA蛋白的原核表达载体,获得高纯度的融合蛋白,制备高效价、高特异性的多克隆抗体。     

AAV9衣壳蛋白VP的原核表达、纯化及多克隆抗体制备

目的：表达腺相关病毒（AAV）9型衣壳蛋白VP,制备抗VP蛋白的多克隆抗体。方法：使用PCR技术从AAV9病毒包装质粒中扩增AAV9衣壳蛋白VP,同源重组法构建衣壳蛋白表达质粒pET30a-AAV9-VP。质粒转化表达菌E.coli BL21(DE3)后,IPTG诱导目的蛋白VP表达,亲和层析法纯化VP蛋白,将纯化后的蛋白免疫日本大耳白兔,3次免疫后获得针对VP蛋白的兔多克隆抗体。以Western blot和细胞免疫荧光法检测抗体的应用,ELISA检测所得抗体的效价。结果：成功构建pET30a-AAV9-VP表达质粒,在大肠杆菌BL21中,IPTG可诱导VP蛋白表达。亲和层析法纯化获得高纯度的VP蛋白。该蛋白在日本大耳兔体内能够诱导产生多克隆抗体,ELISA检测抗血清效价达到1∶512 000。结论：成功原核表达和纯化AAV9衣壳蛋白VP并制备了兔多克隆抗体。制备的抗AAV9 VP抗体能够特异性识别和结合AAV衣壳蛋白,并可有效用于Western blot和细胞免疫荧光分析,为后续深入研究AAV9在基因治疗中的作用及AAV9载体开发提供了研究基础。     

EHEC O157:H7志贺样毒素Ⅱ(Stx2)的克隆表达与活性研究

目的克隆表达肠出血性大肠杆菌(EHEC)O157：H7志贺样毒素Ⅱ(Shiga like toxinⅡ,Stx2),并鉴定其生物学活性。方法采用PCR法自EHEC O157：H7基因组扩增志贺样毒素Ⅱ的编码基因stx2,T-A克隆后构建原核表达质粒pET-11c(+)-six2,经测序鉴定后转化E．coli BL21(DE3),IPTG诱导表达,以SDS-PAGE、Western blot分析目的蛋白的表达。以EHEC O157：H7野生菌株作对照,通过对HeLa细胞的细胞毒作用及对小鼠攻毒实验,鉴定重组蛋白的生物学活性。结果扩增的stx2基因约1230bp；原核表达质粒pET-11c(+)-stx2经酶切和测序鉴定与预期序列一致；并在E．coli BL21 (DE3)中得到表达,蛋白表达率约25％；PAGE初步测定目的蛋白的相对分子质量(M_r)约72×10~3；重组蛋白Stx2对HeLa细胞具有细胞毒作用,CD_(50)为35pg/ml；Stx2对小鼠致死剂量LD_(100)为10μg。结论成功克隆并表达了Stx2重组蛋白,为探讨O157：H7菌的感染机制及其防治研究奠定了一定的基础。     

肠出血性大肠杆菌O157:H7 EspA-Stx2B融合蛋白的克隆、表达及生物学活性研究

目的 重组表达肠出血性大肠杆菌(EHEC)O157:H7的EspA与Stx2B融合蛋白,并对其生物学活性进行初步研究.方法 采用PCR技术从EHEC O157:H7基因组中扩增espA基因及stx2B基因,两基因通过连接子(linker)相连,T/A法克隆,克隆至pET-28a(+)表达载体上,转化宿主细胞E. coli BL21(DE3),IPTG诱导表达,SDS-PAGE检测其表达量及表达形式,免疫印迹分析免疫反应性.用纯化的融合蛋白免疫BALB/c小鼠,检测其免疫原性,然后对免疫小鼠进行O157活菌攻毒试验和O157超声上清致死保护试验.结果 构建的espA-stx2B融合基因片段的测序结果 与理论预测值完全一致.融合蛋白在工程菌中以包涵体的形式表达,表达量约40%.免疫印迹显示融合蛋白能分别与EspA和Stx2B抗体发生抗原抗体反应.免疫小鼠其特异性抗体阳转率达100%,EspA和Stx2B抗体的几何平均滴度(GMT)分别增长了124.30倍和58.49倍.免疫小鼠O157活菌攻毒保护试验免疫后排菌时间和排菌量与对照组相比并没有明显改变,O157菌超声上清致死保护试验免疫组存活率为10/15,对照组全部死亡.结论 在E. coli中高效表达了EspA-Stx2B融合蛋白,此融合蛋白具有良好的免疫原性和免疫反应性,融合蛋白免疫小鼠并不能降低细菌在小鼠胃肠道的黏附与定植,但却起到明显的免疫保护作用,保护率为66.7%(10/15).     

Pain and Effusion and Quadriceps Activation and Strength

Context:

Quadriceps dysfunction is a common consequence of knee joint injury and disease, yet its causes remain elusive.

Objective:

To determine the effects of pain on quadriceps strength and activation and to learn if simultaneous pain and knee joint effusion affect the magnitude of quadriceps dysfunction.

Design:

Crossover study.

Setting:

University research laboratory.

Patients or Other Participants:

Fourteen (8 men, 6 women; age = 23.6 ± 4.8 years, height = 170.3 ± 9.16 cm, mass = 72.9 ± 11.84 kg) healthy volunteers.

Intervention(s):

All participants were tested under 4 randomized conditions: normal knee, effused knee, painful knee, and effused and painful knee.

Main Outcome Measure(s):

Quadriceps strength (Nm/kg) and activation (central activation ratio) were assessed after each condition was induced.

Results:

Quadriceps strength and activation were highest under the normal knee condition and differed from the 3 experimental knee conditions (P < .05). No differences were noted among the 3 experimental knee conditions for either variable (P > .05).

Conclusions:

Both pain and effusion led to quadriceps dysfunction, but the interaction of the 2 stimuli did not increase the magnitude of the strength or activation deficits. Therefore, pain and effusion can be considered equally potent in eliciting quadriceps inhibition. Given that pain and effusion accompany numerous knee conditions, the prevalence of quadriceps dysfunction is likely high.Key Words: arthrogenic muscle inhibition, central activation failure, voluntary activation, muscles

Key Points

• Knee pain and effusion resulted in arthrogenic muscle inhibition and weakness of the quadriceps.
• The simultaneous presence of pain and effusion did not increase the magnitude of quadriceps dysfunction.
• To reduce arthrogenic muscle inhibition and improve muscle strength, clinicians should employ interventions that target removing both pain and effusion.

Quadriceps weakness is a common consequence of traumatic knee joint injury^1,2 and chronic degenerative knee joint conditions.^3,4 Arthrogenic muscle inhibition (AMI), a neurologic decline in muscle activation, results in quadriceps weakness and hinders rehabilitation by preventing gains in strength.⁵ The inability to reverse AMI and restore muscle function can lead to decreased physical abilities,⁶ biomechanical deficits,⁷ and possibly reinjury.⁵ Furthermore, researchers^8,9 have suggested that quadriceps weakness resulting from AMI may place patients at risk for developing osteoarthritis in the knee. In light of the substantial influence of quadriceps AMI on these clinically relevant outcomes, we need to improve our understanding of the factors that contribute to this neurologic decline in muscle activity so efforts to target and reverse it can be implemented and gains in strength can be achieved more easily.Joint injury and disease are accompanied by numerous sequelae (ie, pain, swelling, tissue damage, inflammation), so ascertaining which one ultimately leads to neurologic muscle dysfunction is difficult. Whereas a joint effusion can result in AMI,^10–12 the effects of pain are less understood despite many clinicians attributing AMI to pain. Using techniques that introduce knee pain without accompanying injury may provide insights into the role of pain in eliciting AMI.The degree of knee joint damage may play a role in the quantity of AMI that manifests. Hurley et al^13,14 demonstrated that quadriceps AMI, measured using an interpolated-twitch technique, was greater in patients with extensive traumatic knee injury (eg, fractured tibial plateau, ruptured medial collateral ligament, and medial meniscectomy) than patients with isolated joint trauma (ie, isolated anterior cruciate ligament [ACL] rupture). Similarly, patients with more knee joint symptoms (ie, greater number of symptoms and increased severity of symptoms) may present with greater magnitudes of quadriceps inhibition. Recently, investigators¹⁵ have suggested that patients with more pain display less quadriceps strength, supporting this tenet. Given that effusion and pain often present simultaneously with joint injuries and diseases, such as ACL injury and osteoarthritis, examining both the isolated and cumulative effects of these sequelae appears warranted to determine if they influence the magnitude of muscle inhibition.Experimental joint-effusion and pain models are safe and effective experimental methods that allow for the isolated examination of their effects on muscle function. The effusion model, whereby sterile saline is injected directly into the knee joint capsule,⁷ produces a clinically relevant magnitude of the joint effusion that may be present with traumatic injury. Effusion is thought to activate group II afferents responding to stretch or pressure,^16–18 which in turn may facilitate group Ib interneurons and result in quadriceps AMI.⁵ The pain model involves injecting hypertonic saline into the infrapatellar fat pad to produce anteromedial knee pain similar to that described in patients with patellofemoral pain syndrome.¹⁹ Pain is considered to initiate AMI through activation of group III and IV afferents that act as nocioceptors to signal damage or potential damage to joint structures.^16–18 The firing of these afferents then may lead to facilitation of group Ib interneurons, the flexion reflex, or the gamma loop, ultimately resulting in quadriceps inhibition.²⁰ Thus, these models allow us to create symptoms that are associated with knee injury and have the added benefit of providing a way to examine their effects in isolation.Therefore, the purpose of our study was to determine the effects of pain on quadriceps strength and activation and to learn if simultaneous pain and knee joint effusion would affect the magnitude of quadriceps dysfunction. We hypothesized that pain alone would result in quadriceps inhibition and that the magnitude of inhibition would be greater when effusion and pain were present simultaneously.     

即早基因c-fos与脑血管病及学习记忆

即早基因c-fos是广泛存在于原核细胞和真核细胞的高度保守基因.在正常情况下,c-fos基因参与细胞生长、分化、信息传递、学习和记忆等生理过程,而在病理情况下c-fos基因表达及调控变化与多种疾病的发生和发展有关.C-fos在中枢神经系统的某些部位可有基础水平的表达,但表达很低,当受到如脑缺血、脑出血、痫性发作、应激等刺激后,其在数十分钟内做出反应,在对外界刺激-转录耦联的信忠传递过程中起着核内第三信使的重要作用.     

Opportunities and challenges in the prevention and control of cancer and other chronic diseases: children's diet and nutrition and weight and physical activity

OBJECTIVE: The purpose of this article is to review the role of behavioral research in disease prevention and control, with a particular emphasis on lifestyle- and behavior-related cancer and chronic disease risk factors--specifically, relationships among diet and nutrition and weight and physical activity with adult cancer, and tracking developmental origins of these health-promoting and health-compromising behaviors from childhood into adulthood. METHOD: After reviewing the background of the field of cancer prevention and control and establishing plausibility for the role of child health behavior in adult cancer risk, studies selected from the pediatric published literature are reviewed. Articles were retrieved, selected, and summarized to illustrate that results from separate but related fields of study are combinable to yield insights into the prevention and control of cancer and other chronic diseases in adulthood through the conduct of nonintervention and intervention research with children in clinical, public health, and other contexts. RESULTS: As illustrated by the evidence presented in this review, there are numerous reasons (biological, psychological, and social), opportunities (school and community, health care, and family settings), and approaches (nonintervention and intervention) to understand and impact behavior change in children's diet and nutrition and weight and physical activity. CONCLUSIONS: Further development and evaluation of behavioral science intervention protocols conducted with children are necessary to understand the efficacy of these approaches and their public health impact on proximal and distal cancer, cancer-related, and chronic disease outcomes before diffusion. It is clear that more attention should be paid to early life and early developmental phases in cancer prevention.