Cytogenetics of a new cytotype of African Mus (subgenus Nannomys) minutoides (Rodentia, Muridae) from Kenya: C- and G- banding and distribution of (TTAGGG) n telomeric sequences

We present the results of a cytogenetic study on Mus (Nannomys) minutoides from Kenya by means of C- and G- banding and in-situ fluorescence hybridization (FISH) to localize the telomeric sequences. The karyotype is characterized by the occurrence of several Rb chromosomes Rb(1.X), Rb(1.Y). Rb(2.17), Rb(3.13), Rb(4.10), Rb(5.11), Rb(6.7), Rb(8.12), not previously described for this species. This finding suggests a high level of chromosomal diversification, which means it is possible to consider this cytotype as a new, well-differentiated, chromosomal lineage within the subgenus. The C-banding of the metaphases illustrated conspicuous blocks of centromeric heterochromatin at the paracentromeric regions of all telocentric chromosomes. Centromeric heterochromatin is not visible on all biarmed chromosomes. Following hybridization with telomeric probes, bright interstitial telomeric sequence (ITS) fluorescence signals are evident at the pericentromeric area of all Rb chromosomes, with the exception of Rb(2.17). Considering the localization of the C-positive heterochromatin and of the telomeric sequences, the events leading to the Kenyan cytotype from an all-telocentric condition probably included two steps: first, fusion without loss of heterochromatin and pericentromeric telomeric sequences; second, the reduction of the C-positive satellite DNA followed by the amplification of telomeric sequences in the C-negative paracentromeric region of Rb chromosomes. The presence of a single Rb(2.17) without ITS indicates possible variations of this mechanism.     

一次细胞融合制备分泌抗狂犬病毒单抗杂交瘤及分泌抗独特型单抗杂交瘤的实验研究

根据独特型与抗独特型的免疫网络与免疫调节学说，利用狂犬病毒作为免疫原，设计了不同的动物免疫方案，免疫Ｂａｌｂ／ｃ小鼠，免疫脾细胞与骨髓瘤细胞经一次融合，同时获得了分泌抗狂犬病毒单克隆抗体杂交瘤及分泌狂犬病毒抗独特型单克隆抗体杂交瘤，为抗独特型抗体的制备开辟了一条简捷经济的途径。     

An interaction site of the envelope proteins of Semliki Forest virus that is preserved after proteolytic activation

Semliki Forest virus (SFV) membrane fusion is mediated by the viral E1 protein at acidic pH and regulated by the dimeric interaction of E1 with the E2 membrane protein. During low pH-triggered fusion, the E2/E1 heterodimer dissociates, freeing E1 to drive membrane fusion. E2 is synthesized as a precursor, p62, which is processed to mature E2 by the cellular protease furin. Both the dissociation of the p62/E1 dimer and the fusion reaction of p62 virus have a more acidic pH threshold than that of the mature E2 virus. We have previously isolated SFV mutations that allow virus growth in furin-deficient cells. Here we have used such pci mutations to compare the interactions of the p62/E1 and E2/E1 dimers. Our data suggest that there is an important p62/E1 dimer interaction site identified by an E2 R250G mutation and that this interaction is maintained after processing to the mature E2 protein.     

(His)6 -eIF3s4融合蛋白在人乳腺癌细胞Bcap37中的表达

目的：构建真核细胞翻译起始因子3第4亚单位（eIF3s4）真核表达载体用于进一步功能研究。方法：设计引物,以K562细胞的总RNA为模板,采用RT-PCR方法扩增eIF3s4的全长编码区cDNA,克隆于pGEM-TEasy载体,经DNA测序并与GenBank数据库序列进行比对后,将该cDNA序列亚克隆于真核表达载体pcDNA4/HisMaxB载体,构建成（His）6-eIF3s4融合蛋白的表达载体,用LipofectamineTM2000瞬时转染人乳腺癌细胞株Bcap37,利用Westernblot方法检测（His）6-eIF3s4融合蛋白的表达。结果：DNA序列测定表明,利用RT-PCR方法克隆的eIF3s4全长编码区cDNA序列与GenBank数据库序列一致,Westernblot结果证实（His）6-eIF3s4融合蛋白在Bcap37细胞中获得预期表达。结论：成功地构建了eIF3s4的真核表达载体并在人乳腺癌细胞Bcap37中表达,为建立稳定的eIF3s4高表达细胞系,进而研究eIF3s4与肿瘤细胞多药耐药相关性打下了基础。     

多参数信息融合实现非脑电的睡眠结构分期

目前临床睡眠分析的主要手段是多导睡眠图（Polysomnograph,PSG）,用仪器记录被测者整晚的脑电、眼动电和颏肌电等生理参数,计算机进行自动睡眠分期,再由技术人员依据国际标准进行校正.几十年来PSG保持着睡眠分期金标准的地位.提出在不使用脑电的条件下,利用较易获得的心动周期、呼吸、体动等基本生理参数,提取其中与睡眠过程及其变化有关的规律和信息,建立知识规则库,采用不确定推理的证据理论进行多参数睡眠信息融合计算,实现睡眠结构分期.50余例与PSG对照试验结果表明：醒睡的平均符合率达90%以上,基本睡眠结构的平均符合率达75%以上,证明该技术达到了应用的要求.     

抗Ig融合蛋白Fc段单克隆抗体的制备、鉴定与应用研究

目的：制备并鉴定抗Ig融合蛋白Fc段的单克隆抗体(mAb)，建立用于检测Ig融合蛋白的夹心ELISA法和纯化Fc融合蛋白的亲和层析法。方法：以hBCMA—Ig融合蛋白为抗原免疫BALB／c小鼠，通过细胞融合制备抗Fc段mAb，用ELISA等方法鉴定mAb的Ig亚类、表位以及种属特异性，建立用于检测Ig融合蛋白的夹心ELISA法;Western blot检测mAb对变性Ig融合蛋白的反应性。将mAb与Sepharose4B交联，制备亲和层析柱，对LAIR1-Ig融合蛋白进行纯化。结果：获得7株稳定分泌抗Fc段mAb的杂交瘤(FMUFcl-FMUFc7)。利用FMUFc4作为包被mAb，FMUFc5作为酶标记mAb，成功地建立了检测Ig融合蛋白的ELISA法，敏感度达到2μg／L；在7株mAb中，FMUFc6可用于Ig融合蛋白的western blot检测。用FMUFc 6mAb制备的亲和层析柱，可有效地纯化LAIRl—Ig融合蛋白。结论：成功地制备了抗Ig融合蛋白Fc段的mAb，建立了可用于Ig融合蛋白检测和纯化的方法，为Ig融合蛋白的应用提供了有力手段。     

Mirror-image dental fusion and discordance in monozygotic twins

A pair of monozygotic twins had similar but not identical dental anomalies. One twin had fusion of deciduous mandibular lateral incisor and canine on the left, with normal dentition on the right; the co-twin had right mandibular incisor/canine fusion, with aplasia of the lateral incisor on the left. These findings are discussed in the context of the related phenomena of situs inversus, mirror-imaging in twins, and gradients of severity of anomalies in the four copies of the mandibular developmental dental field. © 1994 Wiley-Liss, Inc.     

Use of λgt11 and monoclonal antibodies to map the gene for the 60,000 dalton glycoprotein of infectious laryngotracheitis virus

To localize the gene encoding the 60 kD glycoprotein (gp60) of infectious laryngotracheitis virus (ILTV), a library of the ILTV genome was constructed in the gt11 expression vector. Twelve recombinant bacteriophages expressing gp60 epitopes as fusion products with -galactosidase were detected by immunoscreening with monoclonal antibodies specific for gp60. The ILTV DNA sequence contained in one of these recombinants 24-4 was used as a hybridization probe for mapping the insert sequence on the viral genome. The gene for the gp60 was located at map unit 0.72–0.77 in the unique long region (U_L) of the ILTV genome. The DNA sequence of the 1.2 kb insert of 24-4 containing the gp60 epitope was determined. The majority of deduced gp60 amino acid sequence has no homology with any of the known alphaherpesvirus glycoproteins.The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession number X 121209.     

Promotion of retroviral entry in the absence of envelope protein by chlorpromazine

Retrovirus packaging cell lines that express the Moloney murine leukemia virus gag, pol, and env genes and a retroviral vector genome can produce virus particles that are capable of transducing cells. Normally if the packaging cell line does not produce a functional viral fusion glycoprotein, such as the retroviral envelope protein or a foreign viral glycoprotein, then the viruses will be incapable of transducing cells. We have found that incubating envelope protein-deficient virus particles bound to cells with chlorpromazine leads to transduction. Chlorpromazine (CPZ) is a membrane-active reagent that is commonly used to induce the hemifusion to fusion transition when membrane fusion is mediated by partially defective viral glycoproteins. The concentration and pH dependence of the promotion of transduction by CPZ is consistent with a role for CPZ micelle formation in viral entry. These data indicate that caution is warranted when experiments concerning membrane fusion completion promoted by CPZ are analyzed.