Sj28GST基因克隆和高效表达产物的纯化

目的　从日本血吸虫中国大陆株成虫cDNA文库中克隆 2 8kDa谷胱甘肽 -S -转移酶 (Sj2 8GST)基因 ,获得用于疫苗和T细胞表位研究的高纯度重组融合蛋白 2 8GST -TRX。方法　应用引物特异性PCR技术 ,从日本血吸虫中国大陆株成虫cDNA文库中扩增Sj2 8GST基因 ,经琼脂糖凝胶电泳结合碱基序列分析鉴定后 ,采用定向克隆技术构建Sj2 8GST -TRX融合蛋白重组表达载体并诱导其在大肠杆菌BL2 1(DE3)的表达 ,用Western -blotting测定以融合蛋白方式表达的Sj2 8GST的免疫原性 ,通过包涵体纯化结合Ni+柱亲和层析获得高纯度重组融合蛋白。结果　Sj2 8GSTPCR产物为约 6 4 0bp ,其碱基序列 (6 33bp)和推导的氨基酸序列 (2 11aa)与GenBank报道一致 ;获得了Sj2 8GST -TRX重组质粒 ;2 8GST -TRX融合蛋白在大肠杆菌以包涵体形式高效表达 ;在分子量为约 4 3kDa处有一能与羊抗Sj2 8GST抗体产生特异性反应的含 2 8GST融合蛋白条带 ;包涵体纯化法结合Ni+ 亲和层析可获得高纯度的重组融合蛋白。结论　获得到了日本血吸虫中国大陆株 2 8GST分子的全长基因和高纯度重组 2 8GST -TRX融合蛋白 ,该融合蛋白具有天然Sj2 8GST免疫原性。     

华支睾吸虫成虫RPEF基因的克隆和表达

目的　构建华支睾吸虫成虫RNA聚合酶Ⅱ延长因子 (RPEF)基因重组质粒 ,分析其编码序列 ,并进行大肠杆菌原核重组表达和免疫鉴定。方法　根据RPEF基因已知序列设计一对引物 ,用常规PCR技术从华支睾吸虫质粒文库模板中扩增RPEF基因片段 ;将目的基因PCR产物和空质粒 pGEX 4T 1同时用BamHⅠ和SalⅠ限制性内切酶双酶切 ,纯化回收后建立连接反应并转化大肠杆菌BL2 1。将构建的重组质粒pGEX 4T 1 RPEF双酶切、PCR、测序鉴定正确后在BL2 1中诱导表达 ,SDS PAGE电泳和Western blot方法鉴定其原核表达效果。结果　成功构建出RPEF基因原核重组质粒 pGEX 4T 1 RPEF。SDS PAGE分析显示RPEF基因在大肠杆菌BL2 1系统中得以高效表达 ,其融合蛋白分子量大约 4 5kD ,与理论值相符。Western blot的结果显示此RPEF融合蛋白可被山羊GST单抗所识别 ,融合蛋白具有GST免疫反应性。结论　筛选到华支睾吸虫RNA聚合酶Ⅱ延长因子 (RPEF)基因 ,并成功构建原核表达载体及在E .coliBL2 1系统中高效表达。     

GST—FHL2融合蛋白的表达及纯化

目的高效表达和纯化可溶性GST—FHL2融合蛋白。方法（1）PCR法扩增FHL2（Four and a half LIM domains2）基因的编码片段，分别在5′端和3′端加上EcoR Ⅰ和Xho Ⅰ酶切位点，并克隆进入原核表达载体pGEX-4T-1；（2）利用异丙基硫代-β-D-半乳糖苷（IPTG）诱导重组质粒pGEX4T-1-FHL2在大肠杆菌B121（DE3）中表达同时带有谷胱甘肽-S-转移酶（GST）标签的融合蛋白；（3）超声法裂解大肠杆菌，应用谷胱苷肽琼脂糖树脂纯化可溶的GST—FHL2融合蛋白；（4）通过SDS—PAGE和Western blot验证GST—FHL2的表达。结果（1）成功构建pGEX-4T-1-FHL2重组质粒，测序结果证明FHL2与载体的GST在同一读框；（2）0．1mmol／L的IPTG在23℃的条件下能诱导可溶性GST—FHL2融合蛋白高效表达；（3）在Western blot分析中，GST—FHL2能被鼠抗GST单克隆抗体特异性识别，条带所在位置和GST-FHL2的分子量相符。结论正确构建pGEX-4T-1-FHL2重组质粒，在大肠杆菌BL21中高效表达GST—FHL2融合蛋白，经谷胱苷肽琼脂糖树脂纯化得到高纯度的可溶性GST-FHL2融合蛋白。     

钩端螺旋体OmpL1抗原表位预测、克隆和表达

目的　应用生物信息学方法预测钩体外膜蛋白OmpL1的表位 ,结合基因工程手段进行表位重组、表达和分离纯化。方法　用预测程序ProPred和ANTIGENIC预测OmpL1的表位 ,PCR合成重组表位基因片段 ,克隆PCR产物构建表达质粒 pGEX/Omp Omp ,测序验证。对含有该质粒的大肠杆菌BL2 1(DE3)进行诱导表达 ,表达产物westernblot分析并纯化融合蛋白。结果　预测到 2个既具有MHC结合肽特性又具有B细胞表位特征的肽段。重组表位基因序列与理论设计完全一致。IPTG诱导BL2 1(DE3)中高效表达Mr约 30 0 0 0的融合蛋白 ,纯化后蛋白纯度 >90 %。结论　成功构建原核表达质粒pGEX/Omp Omp ,并进行含重组表位的GST融合蛋白的分离纯化 ,为OmpL1的表位研究和应用于亚单位疫苗奠定了基础。     

恶性疟原虫Pf12基因在大肠杆菌中的表达及其产物的初步鉴定

目的　克隆并表达恶性疟原虫Pf12基因 ,为进一步研究其抗原表位奠定基础。　方法　将恶性疟原虫Pf12基因克隆入高效融合表达载体 pGEX 4T 1,转化大肠杆菌BL2 1(DE3 ) ,2 8℃、IPTG诱导表达 ,SDS PAGE和Western blot免疫印迹分析表达产物。　结果　成功构建重组质粒 pGEX Pf12 ,经诱导后表达出含外源基因的融合蛋白 ,SDS PAGE分析表达产物分子质量约 66ku ,Western blot免疫印迹表明 ,表达的产物能特异地被抗GST多抗 (1∶5 0 0稀释 )识别 ,亦能较特异地与抗疟原虫鼠免疫血清结合。　结论　恶性疟原虫Pf12在原核表达系统 pGEX 4T 1/BL2 1(DE3 )中获得成功表达 ,为下一步表达蛋白纯化 ,以及研究Pf12基因包含的抗原表位提供试验依据。     

人护骨素-谷胱甘肽转硫酶融合蛋白基因的构建与表达

目的 克隆人护骨素(OPG)成熟肽段编码区基因并研究在大肠杆菌中OPG-谷胱甘肽转硫酶(GST)的融合蛋白的表达。方法 采用RT-PCR从人骨肉瘤细胞系MG63的总RNA中扩增OPG成熟肽段编码区cDNA，构建原核表达载体pGEX-4T-1，转化大肠杆菌后经0．1mmoL／L异丙基硫代半乳糖苷(IPTG)诱导后收集菌体蛋白，以SDS—PAGE电泳及Western印迹鉴定蛋白表达，应用谷胱甘肽-Sepharose4B柱亲和层析纯化目的蛋白。结果 获得人OPG成熟肽段编码区cDNA，转化菌株可表达人OPG-GST融合蛋白，蛋白表达量约为菌体总蛋白的15．5％。Western印迹表明在相对分子质量66000处融合蛋白能与人OPG多克隆抗体特异性结合。经亲和层析后获得纯度为95．7％的OPG—GST融合蛋白。结论 获得人OPG成熟肽段全长cDNA，在大肠杆菌中表达OPG—GST融合蛋白并以亲和层析法进行纯化。     

恶性疟原虫Pfl2基因在大肠杆菌中的表达及其产物的初步鉴定

目的 克隆并表达恶性疟原虫Pfl2基因，为进一步研究其抗原表位奠定基础。方法 将恶性疟原虫Pfl2基因克隆入高效融合表达载体pGEX4T-1，转化大肠杆菌BL21(DE3)，28℃、IPTG诱导表达，SDS-PAGE和Western—blot免疫印迹分析表达产物。结果 成功构建重组质粒pGEX—Pfl2，经诱导后表达出含外源基因的融合蛋白，SDS-PAGE分析表达产物分子质量约66ku，Western-blot免疫印迹表明，表达的产物能特异地被抗GST多抗(1：500稀释)识别，亦能较特异地与抗疟原虫鼠免疫血清结合。结论 恶性疟原虫Pf12在原核表达系统pGEX-4T-1／BL21(DE3)中获得成功表达，为下一步表达蛋白纯化，以及研究Pfl2基因包含的抗原表位提供试验依据。     

日本血吸虫谷胱甘肽-S-转移酶重组质粒的构建及其在大肠埃希菌BL21(DE3)中的表达

目的 构建日本血吸虫谷胱甘肽-S-转移酶(Sj26GST)重组质粒pET32α-Sj26GST,观察该质粒在大肠埃希菌BL21(DE3)中的表达.方法 超声粉碎日本血吸虫成虫,提取总RNA,通过RT-PCR扩增Sj26GST抗原编码基因,克隆至原核表达载体pET32α(+),构建pET32α-Sj26GST,转化大肠埃希菌BL21(DE3),经异丙基硫代-β-D-半乳糖苷(IPTG)诱导表达后,用十二烷基磺酸钠-聚丙烯酰氨凝胶电泳(SDS-PAGE)和Western blot 对表达产物进行分析和鉴定.结果 RT-PCR扩增出676 bp的Sj26GST基因;双酶切和PCR鉴定证实Sj26GST基因成功插入pET32α(+)中,SDS-PAGE分析显示表达产物为相对分子质量约为49×103的重组蛋白,与预期结果一致,表达的蛋白约占菌体总蛋白的24%;Western blot鉴定重组蛋白能被日本血吸虫感染的兔血清识别.结论 成功构建了pET32α-Sj26GST,该质粒在大肠埃希菌BL21中获得了高效融合表达,表达的融合蛋白具有特异的抗原性.     

结核分枝杆菌ESAT-6蛋白的表达与纯化

目的构建结核分枝杆菌esat-6基因原核表达载体,使其在大肠杆菌中表达融合重组蛋白,并纯化。方法用PCR方法从结核分枝杆菌H37Rv基因组中扩增出esat-6基因片段,克隆至pMD18-T载体,PCR筛选阳性克隆并测序;用限制性内切酶消化后,目的片段亚克隆至表达载体pGEX-4T-2,构建pGEX-esat-6重组质粒,将其转化入大肠杆菌JM109;PCR和双酶切鉴定转化菌落;将阳性菌株经IPTG诱导,SDS-PAGE和免疫印迹分析靶蛋白的表达;用谷胱甘肽-琼脂糖亲合层析法纯化融合蛋白。结果PCR扩增出esat-6 288bp的基因,克隆到pMD18-T载体中,经测序与GenBank中序列一致;随后亚克隆到表达载体pGEX-4T-2构建重组表达质粒,在JM109中表达了ESAT-6融合蛋白,表达的蛋白能被GST免疫血清识别;通过亲和层析纯化获得的蛋白能被结核病人血清识别。结论成功构建esat-6重组表达质粒,该质粒在JM109中表达ESAT-6融合蛋白,并获得较纯的蛋白。     

华支睾吸虫一个谷胱甘肽转移酶新基因的克隆与表达

目的 克隆华支睾吸虫(Clonorchis sinensis,Cs)谷胱甘肽转移酶(glutathione transferase,GST)的一个新基因,并在大肠杆菌中表达。方法 用PCR方法从华支睾吸虫成虫cDNA(质粒)文库中扩增新基因CsGST1,对DNA及其推导的氨基酸进行序列分析。将CsGST1克隆到原核表达载体pET-30a(+),在大肠杆菌BL21/DE3表达,用SDS-PAGE鉴定重组蛋白。结果 从华支睾吸虫成虫cDNA(质粒)文库扩增出642 bp的CsGSTl,序列分析显示它所编码的氨基酸序列与麝猫后睾吸虫GST的同源性最高(88％),并具有GST N-末端和C-末端的保守功能域。构建了重组质粒pET-30a(+)-CsGST1,SDS-PAGE显示CsGST1在大肠杆菌中得到了高效表达,pET-30a(+)-CsGST1的蛋白条带的分子量约为30 kDa。结论成功构建了CsGST1的原核表达载体,并在大肠杆菌中得到了高效表达,为进一步研究该基因的功能打下了基础。     

The immunoneuroendocrine role of melatonin

Abstract: A tight, physiological link between the pineal gland and the immune system is emerging from a series of experimental studies. This link might reflect the evolutionary connection between self-recognition and reproduction. Pinealectomy or other experimental methods which inhibit melatonin synthesis and secretion induce a state of immunodepression which is counteracted by melatonin. In general, melatonin seems to have an immunoenhancing effect that is particularly apparent in immunodepressive states. The negative effect of acute stress or immunosuppressive pharmacological treatments on various immune parameters are counteracted by melatonin. It seems important to note that one of the main targets of melatonin is the thymus, i.e., the central organ of the immune system. The clinical use of melatonin as an immunotherapeutic agent seems promising in primary and secondary immunodeficiencies as well as in cancer immunotherapy. The immunoenhancing action of melatonin seems to be mediated by T-helper cell-derived opioid peptides as well as by lymphokines and, perhaps, by pituitary hormones. Melatonin-induced-immuno-opioids (MHO) and lymphokines imply the presence of specific binding sites or melatonin receptors on cells of the immune system. On the other hand, lymphokines such as -γ-interferon and interleukin-2 as well as thymic hormones can modulate the synthesis of melatonin in the pineal gland. The pineal gland might thus be viewed as the crux of a sophisticated immunoneuroendocrine network which functions as an unconscious, diffuse sensory organ.     

Changes in connexin43, the gap junction protein of astrocytes, during development of the rat pineal gland

Abstract: The abundance of gap junctions between rat pineal astrocytes formed by connexin43 (Cx43) was studied during development. Levels and distribution of Cx43 were measured by immunoblotting and indirect immunofluorescence, respectively. The amount of Cx43 in cells located within the gland was low until about the 7th postnatal day and increased to adult values between the 14th and 21st days postpartum. Although astrocytes, recognized by their vimentin immunoreactivity, were scarce before birth, they were abundant by the 7th postnatal day suggesting that the low levels of Cx43 found at this age corresponded to a low expression of this protein. Localization of the immunoreactivity to Cx43 and vimentin showed a close correlation, indicating that mature or immature pineal astrocytes form gap junctions made of Cx43. Since Cx43 levels attained their adult values at about the time the innervation and the functional state of the gland reached maturity (2–3 weeks after birth), it is proposed that astrocyte gap junctions are involved in the function of the adult rat pineal gland.     

Response of rat pineal melatonin to calcium, magnesium, and lithium is circadian stage dependent

Abstract: Herein we documented the response of pineal melatonin production to electrolytes known to be effective on pineal function in view of a possible circadian stage dependence. We studied the release of melatonin by perifused rat pineal glands at 2 different circadian stages corresponding to the middle of the light and dark periods, i.e., respectively, 7 and 19 HALO (Hours After Light Onset, L:D = 12:12). The initial efflux rates were, as expected, much higher in the perifusates of glands removed from rats sacrificed during the dark phase than of those removed during the light phase. After 3 hr of perifusion, melatonin release reached similar levels which were found constant up to the 8th hr of perifusion, whatever the circadian stage. Perifusion of the glands with physiological concentrations for the rat of calcium (5.2 mmol/1) and magnesium (1.34 mmol/1) resulted in a stimulatory effect on the pineal glands removed from rats sacrificed in the middle of the dark period (19 HALO), whereas no effects were observed on the pineal glands removed from rats sacrificed during the light (7 HALO). Lithium (0.28 and 0.55 mmol/1) was ineffective on melatonin release in pineal glands removed 7 and 19 HALO. Our results show differences in the initial efflux rates of melatonin and in the response of perifused pineal glands to calcium and magnesium according to the circadian stage.     

Conservative management of perforated duodenal diverticulum： A case report and review of the literature

Duodenal diverticula are a relatively common condition. They are asymptomatic, unless they become complicated, with perforation being the rarest but most severe complication. Surgical treatment is the most frequently performed approach. We report the case of a patient with a perforated duodenal diverticulum, which was diagnosed early and treated conservatively with antibiotics and percutaneous drainage of secondary retroperitoneal abscesses. We suggest this method could be an acceptable option for the management of similar cases, provided that the patient is in good general condition and without septic signs.     

Presence of immunoreactive growth hormone and prolactin in the ovine pineal gland

Abstract: The use of antisera raised against bovine growth hormone (GH) and ovine prolactin (PRL) enabled the detection of related immunoreactive (ir) sequences of proteins in ovine pineal tissue. The isolation of PRL-like ir-material was accomplished using a 0.25 M ammonium sulphate (pH 5.5) extraction followed by ethanol precipitation, whereas the resulting 2.0 M ammonium sulphate (pH 7.0) precipitate contained a GH-like immunoreactivity. Gel chromatography of the GH-like immunoreactivity (Sephadex G-100) indicated the presence of several GH-like fragments ranging in the M_r range of 7,000 to 55,000. Analyses of the PRL-like ir-material found in pineal tissue on HPLC using a TSK 545-DEAE column led to the resolution into a single peak of immunoreactivity. A single peak of activity was also observed following chromatofocusing and hydrophobic interaction chromatography of the ir-peak from the TSK 545-DEAE column. The PRL-like ir-material inhibited the binding of [¹²⁵I]ovine PRL-S14 to anti-ovine PRL antibodies without showing an affinity for binding to anti-rat PRL or anti-bovine GH antibodies. Scatchard analysis of the binding of pineal PRL-like ir-material and pituitary ovine PRL-S14 to liver membranes from day-20 pregnant rats revealed similar affinity constants (K_a of 4.7 ± 0.2 × 10⁹ M^-1). In addition, the replication of Nb 2 Node rat lymphoma cells was stimulated by pineal PRL-like ir-material, an effect known to be specific for lactogenic hormones. The pineal PRL-like immunoreactivity appeared on sodium dodecyl sulfate polyacrylamide gels as a single major band of M_r 24,000. The functional status of PRL-and GH-like ir-material in the ovine pineal remains to be determined, but evidence is presented that the overall protein synthesis rate of the rat pineal responded to circulating concentrations of PRL.     

Microbiology of human immunodeficiency virus anorectal disease

PURPOSE: Individuals who are seropositive for the human immunodeficiency virus are at high risk for opportunistic infection and anorectal disorders. Little prospective information is available regarding anorectal pathogens in these patients. METHODS: One hundred sixty-three HIV-seropositive patients presented to the colorectal clinic between 1989 and 1992. Forty-seven (29 percent) patients were thought to have an infectious process and were prospectively studied using a standardized multiculture protocol. RESULTS: Mean age was 33 (range, 19–59) years. All were male; high-risk behavior accounted for 87 percent of HIV transmissions. Presenting complaints included anorectal pain (79 percent), pus per anum (28 percent), and blood per anum (26 percent). Examination revealed perianal tenderness (60 percent), condyloma (38 percent), perianal ulcers (38 percent), and anal fissures (34 percent). Sixty-six sets of cultures were performed; 28 patients had one set, 15 had two sets, and 4 had three sets. Thirty-two of these 47 patients (68 percent) had positive cultures including herpes (50 percent), cytomegalovirus (25 percent),Neisseria gonorrhoeae (16 percent), chlamydia (16 percent), acidfast bacilli (2 percent), and others (9 percent). Six of 32 patients with positive cultures had more than one organism cultured. Sixteen (50 percent) patients with positive cultures were treated medically, 8 (25 percent) were treated surgically and 8 (25 percent) were treated with both modalities. Sixty-one procedures were performed on 17 patients for condylomata. Eighteen patients had 20 procedures for abscesses, 50 percent of whom had positive cultures for other than common bowel flora; all improved. Fourteen patients underwent 33 procedures for perianal fistulas.Mycobacterium fortuitum was cultured from one patient who required 13 procedures for abscesses and fistulas. Forty-five (96 percent) patients were followed for an average of 12.5 months ±2.9 SEM (range, 1–94 months). Symptoms were improved or resolved in 22 of 32 (69 percent) patients with positive cultures and in 11 of 13 (84 percent) with negative cultures. CONCLUSIONS: Specific pathogens may often be identified in human immunodeficiency virus-seropositive patients with anorectal disorders if aggressively sought. Although patients without specific pathogens identified may be expected to improve with planned empiric treatment, positive identification allows more directed therapy.