具有抗幽门螺杆菌能力的乳酸菌菌株筛选CSCD

目的 在8株乳酸菌中筛选能够抗幽门螺杆菌感染的乳酸菌菌株,为后续研发治疗幽门螺杆菌感染的益生菌制剂提供依据。方法 在8株乳酸菌菌株中,通过对幽门螺杆菌抑菌率的检测及构建人胃腺癌细胞感染模型检测8株乳酸菌对幽门螺杆菌的抑制作用,以及对尿素酶活性的检测判断8株菌的抗幽门螺杆菌的能力。结果 在抑菌试验中,植物乳植杆菌HCS03-001(t=2.938,P=0.008)和副干酪乳酪杆菌HCS17-040(t=3.864,P=0.006)上清液的抑菌作用较强;植物乳植杆菌HCS03-001、罗伊氏粘液乳杆菌RH02100、副干酪乳酪杆菌HCS17-040能够降低幽门螺杆菌对AGS细胞的黏附能力;通过幽门螺杆菌菌悬液与乳酸菌菌悬液共培养,发现植物乳植杆菌HCS03-001(t=6.257,P<0.001)、副干酪乳酪杆菌HCS17-040(t=5.873,P=0.005)抑制尿素酶活性的作用更强。结论 植物乳植杆菌HCS03-001和副干酪乳酪杆菌HCS17-040具有抗幽门螺杆菌感染的能力。     

乳酸菌抗幽门螺杆菌感染研究的现状

幽门螺杆菌是一种革兰染色阴性,螺旋形,运动活泼,微需氧的的细菌。幽门螺杆菌感染是慢性胃炎和消化性溃疡的重要病因,与胃癌和胃MALT淋巴瘤的发病也相关。乳酸菌,属于益生菌之列,为对人类有益的细菌,其抗幽门螺杆菌感染的效果已经在大量实验中得到确证。目前,临床上将其作为抗生素疗法的佐剂有一定的疗效。但是要在世界范围内完全根除幽门螺杆菌感染,唯一可行的方案就是免疫接种。     

幽门螺杆菌与胃肠道微生态关系的研究进展

幽门螺杆菌作为慢性胃炎、消化性溃疡和胃癌的病原体,大多在儿童期获得,并在成人期持续存在。早期诊断及治疗可有效减少幽门螺杆菌感染相关疾病及不良后果的发生,但儿童幽门螺杆菌感染根除率仍较低,其与幽门螺杆菌药物依从性差及抗生素耐药有关。而欧洲国家儿童幽门螺杆菌感染降低,但儿童早期哮喘、炎症性肠病、胃肠道感染及Barrett食管等疾病的发生率增高。了解胃肠道微生物组与幽门螺杆菌感染的相互作用可能为儿童幽门螺杆菌感染的诊疗及预防提供新的办法。本文就幽门螺杆菌与胃肠道菌群关系研究进展作一综述。     

幽门螺杆菌动物模型研究进展

幽门螺杆菌动物模型用于HP相关疾病和HP疫苗作用的研究。常规实验动物包括悉生猪、悉生狗、非人类灵长动物、猫、雪貂、小鼠、大鼠、沙鼠等。猫螺杆菌和雪貂螺杆菌感染也被用于模型研究。最近,转基因小鼠和基因敲除小鼠也被用作幽门螺杆菌动物模型研究。     

幽门螺杆菌动物模型研究进展

幽门螺杆菌动物模型用于H.pylori相关疾病和H.pylori疫苗作用的研究。常规实验动物包括翻生猪、悉生狗、非人类灵长动物、猫、雪貂、小鼠、大鼠、沙鼠等。猫螺杆菌和雪貂螺杆菌感染也被用于模型研究。最近,转基因小鼠和基因敲除小鼠也被用作幽门螺杆菌动物模型研究。     

幽门螺杆菌感染治疗的新靶位

抗生素治疗幽门螺杆菌感染面临着细菌耐药性的威胁,研究该细菌未知基因的功能,寻找新的抗菌靶,将为预防和治疗幽门螺杆菌感染开辟新途径。将机体适应性免疫应答运用于幽门螺杆菌感染的治疗,亦有广阔前景。     

幽门螺杆菌疫苗的研究进展

幽门螺杆菌疫苗是预防和治疗幽门螺杆菌感染引起的上消化道疾病的有效途径。而疫苗的研制是关键和基础。一种好的疫苗完全可结束人与幽门螺杆菌共存的现象。本文综述了幽门螺杆菌疫苗的研究现状及前景。     

幽门螺杆菌动物感染模型的研究近况

动物感染模型对于幽门螺杆菌致病机制的研究、疫苗的研制和药物的筛选具有十分重要的作用。已报道的用于建立该菌动物感染模型的动物有小鼠、大鼠、蒙古沙鼠、豚鼠、猫、狗、悉生生物猪和灵长类动物等。此外也有人利用猫胃螺杆菌感染的小鼠、大鼠模型和鼬鼠螺杆菌感染的雪貂模型来研究幽门螺杆菌。本文就各种幽门螺杆菌动物感染模型的优缺点、适应范围及存在问题作一简要介绍。     

幽门螺杆菌感染动物模型与疫苗发展

目前认为人是幽门螺杆菌的唯一自然感染宿主,常见其他动物中虽然螺杆菌属细菌感染相当普遍,但并未发现有幽门螺杆菌的自然感染存在;用临床分离的普通幽门螺杆菌菌株感染动物发现,仅有雪貂等少数动物可感染;从大量菌株中筛选出的能够成功定植大、小鼠的幽门螺杆菌菌(如SS1菌株等),虽在致病机制研究及临床药物筛选中发挥了重要作用,但由于其具有与在人类不同的黏附定居机制,无法成功地作为疫苗效果评价中的动物模型使用,国内外使用者均遇到了疫苗动物保护率与在人群中保护率的明显反差问题,成为幽门螺杆菌疫苗发展中的主要瓶颈之一。当前幽门…     

幽门螺杆菌

幽门螺杆菌是一种呈螺旋状或S形、微需氧的革兰阴性杆菌,专一性定居于人胃,是人类慢性胃炎、消化性溃疡、胃癌和胃MALT淋巴瘤的主要病因。幽门螺杆菌在人群中的感染率非常高,达40%~90%,通常在儿童期感染,而且一经感染,若不根除治疗,将终生携带,携带者是幽门螺杆菌的传染源。幽门螺杆菌感染的诊断有侵入性方法如细菌培养、快速脲酶试验等,亦有非侵入性方法如脲呼吸试验、抗体检测等。幽门螺杆菌感染引起胃-十二指肠疾病的机制涉及细菌本身毒力因子、细菌黏附与定植、宿主炎症/免疫反应、氧化应激、细胞的增殖与凋亡等,情况复杂。迄今,幽门螺杆菌的确切致病机制未有定论。幽门螺杆菌相关疾病的治疗普遍采用根除细菌的抗菌疗法。预防幽门螺杆菌感染以及治疗幽门螺杆菌相关疾病的疫苗正在研究中。     

Antitumor effect of photodynamic therapy with zincphyrin, zinc-coproporphyrin III, in mice

We studied the antitumor effects of photodynamic therapy (PDT) with Zincphyrin, coproporphyrin III with zinc, derived from Streptomyces sp. AC8007, in vitro and in vivo. The photokilling effect of Zincphyrin in the presence of 0.78-100 microg/ml with visible light of 27.2 mW x min/cm2 for 10 min was lower than the hematoporphyrin (Hp) used as a control with L5178Y or sarcoma-180 cells. On the other hand, Zincphyrin apparently reduced tumor growth after intraperitoneal injection at doses of 12.5-50 mg/kg with light irradiation of 75.48 mW x min/cm2 for 10 min in sarcoma-180-bearing mice. Although no mice treated with Zincphyrin died, Hp did cause the death of mice. In B-16 melanoma-bearing mice, both Zincphyrin and Hp had a similar phototherapic effect. Further improvement of the phototherapic effect was observed with the continuous administration of Zincphyrin at 12.5 mg/kg per day for 3 days. The concentration of Zincphyrin in the serum reached a maximum level of 16 microg/ml within 20 min, and the concentration remained at 4.2 microg/ml at 1 hour after the onset of treatment, indicating its rapid action in the body. No animals died after the intraperitoneal administration of Zincphyrin at 100 mg/kg plus exposure to light of 10 mW x min/cm2 for 2 hours, and the body weight of the mice did not decrease. In contrast, all animals receiving 100 mg/kg of Hp under the same conditions died. These results indicate that Zincphyrin would be a useful photosensitizer with low phototoxicity.     

Tumor-mediated immunosuppression: prevention by inhibitors of prostaglandin synthesis

The addition of MC16 tumor cells (a prostaglandin E2-producing cell line induced in C57BL/6J mice by methylcholanthrene) to cultures of cells to sheep red blood cells. This inhibition can be blocked by adding to the cultures prostaglandin synthetase inhibitors, such as indomethacin, flufenamic acid and aspirin. These MC16 tumor cells are also immunosuppressive in vivo. Mice bearing the syngeneic MC16 tumor become unresponsive to sheep red blood cells as the tumor grows. As in the in vitro test system, inhibitors of prostaglandin synthetases seem to block the immunosuppressive activity of MC16 cells in vivo since tumor-bearing mice, treated therapeutically with indomethacin, responded normally in their production of antibody to sheep red blood cells.     

Obesity modulates the expression of haptoglobin in the white adipose tissue via TNFalpha.

Increase in adipose mass results in obesity and modulation of several factors in white adipose tissue (WAT). Two important examples are tumor necrosis factor alpha (TNFalpha) and leptin, both of which are upregulated in adipose tissue in obesity. In order to isolate genes differentially expressed in the WAT of genetically obese db/db mice compared to their lean littermates, we performed RNA fingerprinting and identified haptoglobin (Hp), which is significantly upregulated in the obese animals. Hp is a glycoprotein induced by a number of cytokines, LPS (Lipopolysaccharide), and more generally by inflammation. A significant upregulation of WAT Hp expression was also evident in several experimental obese models including the yellow agouti (/) A(y), ob/ob and goldthioglucose-treated mice (10-, 8-, and 7-fold, respectively). To identify the potential signals for an increase in Hp expression in obesity, we examined leptin and TNFalpha in vivo. Wild type animals treated with recombinant leptin did not show any alteration in WAT Hp expression compared to controls that were food restricted to the level of intake of the treated animals. On the other hand, Hp expression was induced in mice transgenically expressing TNFalpha in adipose tissue. Finally, a significant downregulation of WAT Hp mRNA was observed in ob/ob mice deficient in TNFalpha function, when compared to the ob/ob controls. These results demonstrate that haptoglobin expression in WAT is increased in obesity in rodents and TNFalpha is an important signal for this regulation.     

幽门螺杆菌球形体回复原形的实验研究

目的对幽门螺杆菌（Helicobacter pylori,Hp）球形体进行体内、外回复原形的比较研究,揭示其潜在的传播途径。方法在布氏肉汤的基础上设计了4种Hp再生培养基,对Hp螺旋体、原生质体及球形体进行体外培养;同时采用30只蒙古沙土鼠（Mongolian gerbil）进行体内感染定植实验,对感染小鼠胃粘膜进行Hp定量培养和组织学检测。结果Hp球形体在4种再生培养基中均未能回复生长;而在感染小鼠的体内却观察到了Hp球形体的回复定植。Hp螺旋体感染组在小鼠胃内的定植密度较高,且胃粘膜下可见大量炎症细胞浸润;而球形体感染组并未见到小鼠胃粘膜组织的明显炎症损伤,且仅有少量回复的螺旋体定植。结论Hp球形体作为一种低水平代谢休眠体,代谢活性及毒力均有所减弱,但仍具有潜在的致病性。本研究支持部分Hp球形体具有活力但体外不能培养成活这一假说,提示＂粪-口＂传播应引起更多的关注。     

大熊猫粪便乳酸菌的分离鉴定

大熊猫作为国家保护动物,其健康问题备受瞩目。为了维护大熊猫的肠道健康,本研究从大熊猫肠道内分离出适宜于大熊猫肠道环境的乳酸菌菌株,有望将其制成熊猫肠道微生物制剂,从而改善大熊猫肠道菌群环境。从雅安市宝兴县蜂桶寨自然保护区选取圈养与野生大熊猫的粪便,通过体外培养分离出9个菌株。分离菌株经过革兰氏染色镜检、过氧化氢产气、菌落形态观察等方法与技术初步鉴定为乳酸菌。对这9株乳酸菌进行耐酸试验、耐胆盐试验、抑菌能力试验和产酸能力等测试,筛选出了3个适应性较强,有望制成调节大熊猫肠道内环境平衡作用的微生态菌剂的菌株。16S rRNA基因序列分析表明:分离菌株J1、J2和J4分别为融合魏斯氏菌（Weissella confusa）,海氏肠球菌（Enterococcus heynei）和非解乳糖链球菌（Streptococcus alactolyticus）,有望被应用于大熊猫肠道微生态制剂的研究。     

幽门螺旋杆菌ATCC 43504感染BALB/c小鼠动物胃炎模型的建立及分析

利用幽门螺旋杆菌标准菌株建立稳定可靠的幽门螺旋杆菌(Helicobacter pylori,Hp)感染小鼠胃炎模型对Hp疫苗研制、Hp致病机制的研究及抗Hp药物的筛选具有重要意义。通过灌胃国际标准菌株幽门螺旋杆菌Hp ATCC 43504,构建了BALB/c小鼠动物胃炎模型。利用小鼠胃部Hp尿素酶活性检测、Hp的定量培养、PCR检测、组织病理学等多种方法鉴定BALB/c小鼠动物胃炎模型。通过Hp诊断试剂盒检测,造模组小鼠的胃组织能使Hp尿素酶试剂变色,呈现玫瑰红色,而健康小鼠的胃组织不能使Hp尿素酶试剂变色,依旧呈现黄色;通过小鼠胃组织匀浆液培养Hp,造模组小鼠的胃组织匀浆液均可在BHI血平板长出Hp菌落,而对照组小鼠的胃组织匀浆液不能培养出Hp菌落;利用PCR对造模组和对照组BALB/c小鼠的胃组织进行Hp检测,造模组小鼠胃组织可扩增出150 bp的DNA产物,而对照组小鼠胃组织无扩增产物;通过HE染色法观察小鼠胃部病理变化和炎症情况,与健康BALB/c小鼠比较,造模组小鼠胃粘膜和粘膜下层有大量白细胞浸润,胃部炎症明显。利用国际标准菌株Hp ATCC 43504菌株成功构建了BALB/c小鼠胃炎模型,为评价防治Hp感染药物的效果奠定了实验基础。     

Immunogenicity of 2 murine B16 melanoma variants with high metastatic potential

The expression of tumor-associated transplantation antigens (TATA) by two metastatic variants, isolated from B16 melanoma in vivo, was examined. The first, YB16 melanoma (amelanotic), was selectioned after a successive s. c. transplantations of B16 melanoma cells on the coisogenic Yellow AY/a mutant mice of C57BL/6J mice. The second, MB16 melanoma, characterized by a variable pigmentation, was obtained from a s. c. transplantation of YB16 melanoma cells on C57BL/6J mice. The comparison of TATA expressed by the two variants and the B16 melanoma, made between different modes of inducing tumor-rejection activity, revealed that i) these two variants failed to induce an autologous antitumor response, ii) they were resistant to crossed immunization with an immunogenic preparations of B16 melanoma and iii) only MB16 melanoma preparations reduced significantly the tumoral incidence of B16 melanoma cells. These data leads us to suggest i) that the s. c. transplantation of B16 melanoma cells on Yellow AY/a mice resulted in the selection of nonimmunogenic, amelanotic and metastatic cell population of YB16 melanoma and ii) the existence of an epigenetic regulation of melanogenesis and expression of TATA in MB16 melanoma cells carried on C57BL/6J mice.     

小鼠溃疡性结肠炎模型的建立及病理组织学比较

目的建立乙酸,右旋葡聚糖硫酸钠（dextran sodium sulfate,DSS）,幽门螺杆菌（Helicobacter pyliri）小鼠溃疡性结肠炎（ulcerative colitis）动物模型,通过病理学对比观察,选择最佳的小鼠溃疡性结肠炎动物模型。方法将40只清洁级BALB/c小鼠随机分为4组,实验组中Ⅰ组采用乙酸刺激法诱发溃疡性结肠炎,Ⅱ组采用饮用3.5%DSS溶液诱发结肠炎,Ⅲ组采用幽门螺杆菌感染小鼠诱发溃疡性结肠炎,对照组饮用蒸馏水。观察小鼠每日的体重,大便性状和隐血情况,以及结肠大体形态和组织病理学改变。结果乙酸,右旋葡聚糖硫酸钠均可引起小鼠疡性结肠炎。结论 DSS诱发的小鼠溃疡性结肠炎是一种较理想的UC动物模型,可作为研究UC发病机制和药物治疗较理想的工具。     

乳酸菌对高脂小鼠降胆固醇作用的研究

目的探讨乳酸菌对高脂小鼠降胆固醇的作用。方法对昆明小鼠饲喂高脂饲料14 d建立高脂小鼠模型,确定模型建立成功后用1株经体外实验证实具有降胆固醇效果的乳酸菌对小鼠灌胃,测定小鼠经灌胃14、28 d的脏器指数、血清胆固醇含量和肝脏胆固醇含量。结果灌胃组小鼠脏器指数明显低于高脂组小鼠,且对于血清和肝脏胆固醇含量具有明显的降低作用。结论该菌株具有降低血清胆固醇,抑制肝脏胆固醇堆积的功能,为将来利用该菌株制作出降胆固醇功能的食品或药品提供实验基础。     

Effects of intranasal administration of a leptin-secreting Lactococcus lactis recombinant on food intake, body weight, and immune response of mice

Leptin is an adipocyte-derived pleiotropic hormone that modulates a large number of physiological functions, including control of body weight and regulation of the immune system. In this work, we show that a recombinant strain of the food-grade lactic acid bacterium Lactococcus lactis (LL-lep) can produce and efficiently secrete human leptin. The secreted leptin is a fully biologically active hormone, as demonstrated by its capacity to stimulate a STAT3 reporter gene in HEK293 cells transfected with the Ob-Rb leptin receptor. The immunomodulatory activity of leptin-secreting L. lactis was evaluated in vivo by coexpression with the human papillomavirus type 16 E7 protein. In C57BL/6 mice immunized intranasally with a recombinant L. lactis strain coproducing leptin and E7 antigen, the adaptive immune response was significantly higher than in mice immunized with recombinant L. lactis producing only E7 antigen, demonstrating adjuvanticity of leptin. We then analyzed the effects of intranasally administered LL-lep in obese ob/ob mice. We observed that daily administration of LL-lep to these mice significantly reduced body weight gain and food intake. These results demonstrate that leptin can be produced and secreted in an active form by L. lactis and that leptin-producing L. lactis regulates in vivo antigen-specific immune responses, as well as body weight and food consumption.