实验树鼩配合饲料的研究与应用

根据树鼩的生物学特性并参考有关实验动物饲料标准为树鼩设计和加工生产一种实验饲育饲料。结果表明该饲料能满足树鼩的健康生长、饲养繁殖和实验树鼩的营养需求。该饲料的营养成分和混合均匀度均符合地方标准,生产和饲喂方便,具有一定的应用和推广前景。     

树鼩的血相

关于树鼩(Tupaia belangeri chinensis)和它的分类至今还有争论。一些学者将其归入食虫目,另一些学者则根据其性周期和神经系统接近于灵长目的特点,又把它划归灵长目。总之,树鼩目前尚处于一个独特的位置上,其分类有待确定。 1981年有人用甲、乙型肝炎病毒感染树鼩,已见可喜的苗头。继之,轮状病毒又感染树鼩成功。在血脂代谢的研究方面,已有人将其用作动物模型。另外,G.Darai等人发现树鼩还有多种自发性肿瘤,其中之一是何杰金氏病——淋巴结恶性肿瘤,因此,树鼩也可     

综述与专论: 树鼩病毒感染模型的研究新进展

病毒感染引起的疾病接近中国主要传染病发病率的一半,也是传染病致死的主要病因。建立与人类亲缘关系较近、方便有效的感染人类病毒的动物模型,对了解病毒的生物学特性、感染致病机理及制定有效防控措施具有重要意义。树鼩作为灵长类动物的近亲,与人类在生理生化、基因组学等方面的相似性远高于大鼠、小鼠等常用啮齿类实验动物,并具有个体小、便于实验操作、饲养成本低、能感染多种人类病毒等特点,作为动物模型在病毒感染性疾病研究中突显优势和潜能。本文从地区分布、进化、生物学特性等方面,阐述了树鼩作为动物模型应用于病毒感染性疾病研究的优势,包括在乙型肝炎病毒、甲型肝炎病毒,及其他病毒感染疾病研究中的进展。     

树鼩在医学实验研究中的新进展

树鼩的许多生物学特性近似于人类,人们利用树鼩成功建立了多种人类病毒感染的动物模型,并在肿瘤、内分泌、神经、视觉等方面有相当广泛和深入的应用和研究。本文概述了树鼩在医学实验研究中的新进展。     

水稻叶片全营养成分分析及在稻纵卷叶螟人工饲料研制中的应用

稻纵卷叶螟Cnaphaolcrosis medinalis Guenée是我国水稻上的一种重要迁飞性害虫,该虫在室内难以进行人工饲养,这是制约其生物学、生态学及防控技术研究的关键因素。为此,本文开展了稻纵卷叶螟抗、感水稻品种叶片的全营养成分分析及其比较研究,找出了影响稻纵卷生长、发育和繁殖的关键营养因子,并给出了关键营养成分在人工饲料中的合理配比。该研究可望为稻纵卷叶螟人工饲料的研制提供借鉴和参考。     

正常树驹乳酸脱氢酶同工酶等的血清学调查

近年来,研究者利用云南树鼩(Tupaia glis yunnalis)做了不少试验,如甲型肝炎、乙型肝炎的实验动物模型。这些实验的一个特点是对树鼩在自然生活状态下的各种生化指标做得比较少。这次,我们对80只树鼩血清乳酸脱氢酶同工酶(LDH)、乙型肝炎表面抗原(HBsAg)、抗甲肝病毒IgG抗体(HAV-IgG)及谷丙转氨酶(SGPT)进行了检测。兹报告     

饲养条件下非人灵长类的营养需求

非人灵长类的营养学研究越来越受到国际和国内社会的关注。我国是世界上实验灵长类动物的最大产出国。进一步了解和发展非人灵长类营养学将有利于提高我国非人灵长类的饲养水平和饲料资源的利用效率,推动整体产业的发展。为此本文介绍了近年来国际上非人灵长类营养学方面的研究进展和国家饲料配比的相关规定,阐述了各营养成分的作用、缺乏症状和改善案例。旨在丰富相关方面的科学信息,增加对非人灵长类营养
需求的理解。     

乙肝研究的历史回顾及其哲学思考

乙型肝炎的研究可以分为病因学、感染传播机制和防治三部分,涵盖了流行病学、传染病学、生物化学、病理学、分子生物学等多种学科。随着现代科学技术的快速发展和进步,过去十年我们才对乙型肝炎进行了科学、系统的研究。本文主要回顾了乙型肝炎的研究史,我们发现正确的研究方法和科学思路在揭示乙型肝炎发病机制、病毒感染传播、乙型肝炎预防和治疗中起到了关键的作用。客观辨证地分析单个机体内部、周围环境和人群间的关系、人群研究和实验室研究、基础研究和临床研究、传统方法和现代高科技的有机结合、微观研究和宏观研究相结合,是乙型肝炎研究突破的重要环节。     

乙肝病毒与原发性肝癌的相关风险研究

为了解慢性乙型肝炎病毒感染与原发性肝癌的关系,本文采用回顾性研究方法对328例原发性肝癌病人与同期收治的340例非肝癌的其他消化道肿瘤病人的乙型肝炎病毒感染血清标志物(HBV M)及肝功能检测结果进行对比分析.结果显示肝癌组乙肝表面抗原(HBsAg)阳性率(63.11%)显著高于非肝癌组(消化道其他肿瘤对照组)(11.47%).肝癌组慢性乙型肝炎病毒感染"HBsAg、抗-HBe和抗-HBc三者均表达为阳性者"(37.2%)显著高于"HBsAg、HBeAg和抗-HBc三者均表达为阳性者"(6.4%).肝功能检测结果,"HBsAg、HBeAg和抗-HBc三者均表达为阳性组"与"HBsAg、HBeAg和抗-HBc三者均表达为阳性组"比较无显著性差异(P＞0.05),而肝癌组与非肝癌组比较,肝癌组肝损害显著高于非肝癌组(P＜0.01).表明慢性乙型肝炎病毒感染在原发性肝癌病因学中起着十分重要的作用,"HBsAg、抗-HBe和抗-HBc三者均表达为阳性者"是原发性肝癌的高危人群.     

乙肝病毒与原发性肝癌的相关风险研究

为了解慢性乙型肝炎病毒感染与原发性肝癌的关系,本文采用回顾性研究方法对 328 例原发性肝癌病人与同期收治的 340 例非肝癌的其他消化道肿瘤病人的乙型肝炎病毒感染血清标志物(HBV M)及肝功能检测结果进行对比分析。结果显示肝癌组乙肝表面抗原(HBsAg)阳性率(63.11%)显著高于非肝癌组(消化道其他肿瘤对照组)(11.47%)。肝癌组慢性乙型肝炎病毒感染“HBsAg、抗-HBe 和抗-HBc 三者均表达为阳性者”(37.2%)显著高于“HBsAg、HBeAg 和抗-HBc 三者均表达为阳性者”(6.4%)。肝功能检测结果,“HBsAg、HBeAg 和抗-HBc三者均表达为阳性组”与“HBsAg、HBeAg 和抗-HBc 三者均表达为阳性组”比较无显著性差异(P>0.05),而肝癌组与非肝癌组比较,肝癌组肝损害显著高于非肝癌组(P<0.01)。表明慢性乙型肝炎病毒感染在原发性肝癌病因学中起着十分重要的作用,“HBsAg、抗-HBe 和抗-HBc 三者均表达为阳性者”是原发性肝癌的高危人群。     

Tupaia CD81, SR-BI, claudin-1, and occludin support hepatitis C virus infection

Hepatitis C virus (HCV)-related research has been hampered by the lack of appropriate small-animal models. It has been reported that tree shrews, or tupaias (Tupaia belangeri), can be infected with serum-derived HCV. However, these reports do not firmly establish the tupaia as a reliable model of HCV infection. Human CD81, scavenger receptor class B type I (SR-BI), claudin 1 (CLDN1), and occludin (OCLN) are considered essential receptors or coreceptors for HCV cell entry. In the present study, the roles of these tupaia orthologs in HCV infection were assessed. Both CD81 and SR-BI of tupaia were found to be able to bind with HCV envelope protein 2 (E2). In comparison with human CD81, tupaia CD81 exhibited stronger binding activity with E2 and increased HCV pseudoparticle (HCVpp) cell entry 2-fold. The 293T cells transfected with tupaia CLDN1 became susceptible to HCVpp infection. Moreover, simultaneous transfection of the four tupaia factors into mouse NIH 3T3 cells made the cells susceptible to HCVpp infection. HCVpp of diverse genotypes were able to infect primary tupaia hepatocytes (PTHs), and this infection could be blocked by either anti-CD81 or anti-SR-BI. PTHs could be infected by cell culture-produced HCV (HCVcc) and did produce infectious progeny virus in culture supernatant. These findings indicate that PTHs possess all of the essential factors required for HCV entry and support the complete HCV infection cycle. This highlights both the mechanisms of susceptibility of tupaia to HCV infection and the possibility of using tupaia as a promising small-animal model in HCV study.     

Efficient infection of primary tupaia hepatocytes with purified human and woolly monkey hepatitis B virus

The Asian tree shrew, Tupaia belangeri, has been proposed as a novel animal model for studying hepatitis B virus (HBV) infection. Here, we describe a protocol for efficient and reproducible infection of primary tupaia hepatocytes with HBV. We report that human serum interferes with HBV binding to the hepatocytes, thus limiting the maximum multiplicity of infection. Purification of HBV virions by gradient sedimentation greatly enhances virus binding and infectivity. Covalently closed circular DNA was clearly detectable by Southern blot analysis and newly synthesized single-stranded HBV DNA was visible 2 weeks postinoculation. Primary tupaia hepatocytes are also susceptible to infection with the recently discovered woolly monkey hepatitis B virus (WMHBV) but not to woodchuck hepatitis virus infection. Compared to HBV, WMHBV replicated at a higher rate with single-stranded DNA detectable within the first week postinoculation. Primary tupaia hepatocytes should represent a useful system for studying early steps of HBV and WMHBV infection.     

Detection of glucagon in pancreatic A-cells by monoclonal antibodies

Summary The production of a mouse monoclonal antibody from a hybrid myeloma and its use for the detection of glucagon in tissue sections is reported. The hybrid clone isolated after fusion of mouse myeloma cells with hyperimmune spleen cells from a mouse previously immunized with poreine glucagon allowed us a standardized and permanent source of monoclonal antibodies in a culture cell system. The monoclonal antibody (3 GL 31) specifically reacts with pancreatic A-cells in several species including pig, rabbit, tupaia belangeri and sheep. No immunoreactivity is observed against gut cells and neurons.Supported by the Deutsche Forschungsgemeinschaft, Carvas SFB 90     

Pre-s1 antigen-dependent infection of Tupaia hepatocyte cultures with human hepatitis B virus

The susceptibility of the tree shrew Tupaia belangeri to human hepatitis B virus (HBV) has been demonstrated both in vivo and in vitro. In this study, we show that purified HBV infects primary T. belangeri hepatocyte cultures in a very specific manner, as detected by HBV covalently closed circular DNA, mRNA, HBV e antigen, and HBsAg production. A monoclonal antibody (MAb), MA18/7, directed against the pre-S1 domain of the large HBs protein, which has been shown to neutralize infectivity of HBV for primary human hepatocytes, also blocked infection of primary Tupaia hepatocytes. MAbs against the pre-S2 domain of HBs inhibited infection only partially, whereas an S MAb and polyvalent anti-HBs antibodies neutralized infection completely. Thus, both pre-S1 and S antigens are necessary for infection in the tupaia. Using subviral particles, >70% of primary Tupaia hepatocytes are capable of specific binding of pre-S1-rich HBsAg, showing localization in distinct membrane areas. The data show that the early steps of HBV infection in Tupaia hepatocyte cultures are comparable to those in the human system.     

滇西亚种树鼩体外寄生虫自然感染状况及分析

目的调查滇西亚种树鼩体外寄生虫的自然感染状况,为建立树鼩质量控制标准提供依据。方法对野生的滇西亚种树鼩和自繁F1代树鼩各60只分别用尸检法和活体法检测,随即采用拔毛或用透明胶带粘取腋下、耳根、腹股沟、肛门附近等处的毛发制片,置于体视镜和显微镜下观察虫体和虫卵。结果野生滇西亚种树鼩和自繁F1代树鼩体外寄生虫自然感染率分别为：虱子25%/6%、蚤5%/0、蜱1.6%/0、水蛭1.6%/0、虱子和蚤混合感染1.6%/0。结论野生树鼩体外寄生虫的自然感染多为虱子和蚤,其次还有蝉、水蛭,总感染率明显高于自繁F1代。使用灭虱灵对于驱除树鼩体外寄生虫具有较好的疗效。     

Molecular cloning and physical mapping of the tupaia herpesvirus genome.

Purified virion DNA of about 200 kilobase pairs of tupaia herpesvirus strain 2 was cleaved with EcoRI or HindIII restriction endonuclease. Restriction fragments representing the complete viral genome including both termini were inserted into the EcoRI, HindIII, and EcoRI-HindIII sites of the bacterial plasmid pAT153. Restriction maps for the restriction endonucleases EcoRI and HindIII were constructed with data derived from Southern blot hybridizations of individual viral DNA fragments or cloned DNA fragments which were hybridized to either viral genome fragments or recombinant plasmids. The analysis revealed that the tupaia herpesvirus genome consists of a long unique sequence of 200 kilobase pairs and that inverted repeat DNA sequences of greater than 40 base pairs do not occur, in agreement with previous electron microscopic data. No DNA sequence homology was detectable between the tupaia herpesvirus DNA and the genome of murine cytomegalovirus, which was reported to have a similar structure. In addition, seven individual isolates of tupaia herpesvirus were characterized. The isolates can be grouped into five strains by their DNA cleavage patterns.     

Distribution of 239Pu in the skeleton of the tree shrew (Tupaia belangeri) between 15 and 50 months after injection

The macroscopic and microscopic distribution of intramuscularly injected, essentially monomeric, 239Pu was studied in the skeleton of the adult tree shrew (Tupaia belangeri). Data for the period between 15 and 50 months after injection are presented and compared with the data from earlier time points. Between 83 and 500 days after injection the nuclide content and the wet weight of the skeleton decreased to a constant level at about 55 per cent of the maximum values. The microscopic distribution has been analysed in distal femora, proximal humerus, proximal tibia and lumbar vertebra over the whole observation time; additionally at some selected time points proximal femur, femur shaft, distal humerus and distal tibia were analysed. The initial endosteal surface activity ranged from 3.8 to 5.3 Bq/cm2 and decreased to a minimum at about 1000 days after injection and increased thereafter. A similar behaviour was found for the dose rate near bone surfaces which was initially about 0.075 Gy/day on endosteal surfaces. In the deep bone and the deep marrow the dose rate was negligible, about 0.008 Gy/day and 0.001 Gy/day, respectively. The average cumulative dose 1500 days after injection was about 67 Gy on the endosteum, six times greater than the cumulative dose calculated from the mean concentration of plutonium in the whole skeleton. All values are normalized to an injected activity of 37 kBq/kg body weight. The tupaia data are discussed in relation to the available data from monkeys, dogs and rats.     

Protein kinase and specific phosphate acceptor proteins associated with tupaia herpesvirus.

A protein kinase activity was found to be associated with tree shrew (tupaia) herpesvirus. The protein kinase was characterized with respect to its requirements for enzymatic activity. A divalent cation such as Mg2+ or Mn2+ was necessary as well as ATP as the phosphate donor. Distinct tupaia herpesvirus polypeptides (molecular weights of 100,000 [100K], 82K, and 53K) were found to be phosphate acceptor proteins when 5 mM Mg2+ was used. At a higher Mg2+ concentration (20 mM), additional viral proteins (220K, 71K, 31K, and 20K) were phosphorylated. The viral phosphoproteins were analyzed by chemical and enzymatic hydrolyses. The predominant sites of phosphorylation were the beta-OH groups of the serine and threonine residues of these tupaia herpesvirus proteins. Kinase activity was not stimulated by cyclic nucleoside monophosphates. Endogenously added proteins did not enhance protein kinase activity. Protein kinase activity was inhibited by 5'-p-fluorosulfonylbenzoyladenosine.     

Scavenger receptor class B type I and hepatitis C virus infection of primary tupaia hepatocytes

Hepatitis C virus (HCV) is a major cause of chronic hepatitis worldwide. The study of early steps during HCV infection has been hampered by the lack of suitable in vitro or in vivo models. Primary Tupaia hepatocytes (PTH) have been shown to be susceptible to HCV infection in vitro and in vivo. Human scavenger receptor class B type I (SR-BI) represents an HCV receptor candidate mediating the cellular binding of E2 glycoprotein to HepG2 hepatoma cells. However, the function of SR-BI for viral infection of hepatocytes is unknown. In this study, we used PTH to assess the functional role of SR-BI as a putative HCV receptor. Sequence analysis of cloned tupaia SR-BI revealed a high homology between tupaia and human SR-BI. Transfection of CHO cells with human or tupaia SR-BI but not mouse SR-BI cDNA resulted in cellular E2 binding, suggesting that E2-binding domains between human and tupaia SR-BI are highly conserved. Preincubation of PTH with anti-SR-BI antibodies resulted in marked inhibition of E2 or HCV-like particle binding. However, anti-SR-BI antibodies were not able to block HCV infection of PTH. In conclusion, our results demonstrate that SR-BI represents an important cell surface molecule for the binding of the HCV envelope to hepatocytes and suggest that other or additional cell surface molecules are required for the initiation of HCV infection. Furthermore, the structural and functional similarities between human and tupaia SR-BI indicate that PTH represent a useful model system to characterize the molecular interaction of the HCV envelope and SR-BI on primary hepatocytes.