Ф40自由浮球式疏水阀工况分析

对自由浮球式疏水阀内浮球在开启过程中的受力情况进行了全面的分析,首次提出疏水阀开启疏水的两种不同方式。即滑动开启和滚动开启方式,并分别给出了两种不同开启方式所对应的压差合力和关闭力矩的计算公式。确定了保证此类疏水阀可靠工作的许用最高工作压力。可供此类疏水阀设计和开发参考。     

模拟移动床分离紫杉醇

以东北红豆杉树叶为原料,采用无毒、无污染的乙醇作为提取溶剂．在高分子树脂柱和模拟移动床色谱(SMBC)系统上逐级提纯紫杉醇,除去大量非紫杉烷与紫杉烷类杂质,得到了高纯度的产品、同时,对紫杉醇前处理过程中洗脱液条件,随后的SMBC系统实验中的切换时间等条件进行了优化,并总结出一套优化操作条件,为纯化紫杉醇提供了合理的工艺路线．     

Mutations in the 70K peroxisomal membrane protein gene in Zellweger syndrome.

The peroxisomal membrane protein, with a relative molecular mass of 70,000 (M(r) 70K) (PMP70), is an important component of peroxisomal membranes and an ATP-binding cassette protein. To investigate its possible involvement in Zellweger syndrome (ZS), an inborn error of peroxisome assembly, we cloned and sequenced cDNAs for human PMP70 and mapped the gene to chromosome 1. Amongst 32 probands with ZS or related disorders, we found two mutant PMP70 alleles in single ZS probands from the same complementation group. One allele has a donor splice site mutation and the second a missense mutation. Our results suggest that PMP70 plays an important role in peroxisome biogenesis and that mutations in PMP70 may be responsible for a subset of ZS patients.     

Isolation of a candidate gene for Norrie disease by positional cloning.

The gene for Norrie disease, an X-linked disorder characterized by progressive atrophy of the eyes, mental disturbances and deafness, has been mapped to chromosome Xp11.4 close to DXS7 and the monoamine oxidase (MAO) genes. By subcloning a YAC with a 640 kilobases (kb) insert which spans the DXS7-MAOB interval we have generated a cosmid contig which extends 250 kb beyond the MAOB gene. With one of these cosmids, microdeletions were detected in several patients with Norrie disease. Screening of cDNA libraries has enabled us to isolate and sequence a likely candidate gene for Norrie disease which is expressed in retina, choroid and fetal brain. No homologous sequences were found in DNA and protein databases indicating that this cDNA is part of a gene encoding a 'pioneer' protein.     

Small nuclear ribonucleoprotein polypeptide N (SNRPN), an expressed gene in the Prader-Willi syndrome critical region.

Prader-Willi syndrome (PWS) is associated with paternally derived chromosomal deletions in region 15q11-13 or with maternal disomy for chromosome 15. Therefore, loss of the expressed paternal alleles of maternally imprinted genes must be responsible for the PWS phenotype. We have mapped the gene encoding the small nuclear RNA associated polypeptide SmN (SNRPN) to human chromosome 15q12 and a processed pseudogene SNRPNP1 to chromosome region 6pter-p21. Furthermore, SNRPN was mapped to the minimal deletion interval that is critical for PWS. The fact that the mouse Snrpn gene is maternally imprinted in brain suggests that loss of the paternally derived SNRPN allele may be involved in the PWS phenotype.     

Ornithine decarboxylase activity is critical for cell transformation.

The enzyme ornithine decarboxylase is the key regulator of the synthesis of polyamines which are essential for cell proliferation. Expression of this enzyme is transiently increased upon stimulation by growth factors, but becomes constitutively activated during cell transformation induced by carcinogens, viruses or oncogenes. To test whether ornithine decarboxylase could be a common mediator of transformation and oncogenic itself, we transfected NIH3T3 cells with expression vectors carrying the complementary DNA encoding human ornithine decarboxylase in sense and antisense orientations. The increased expression of the enzyme (50-100-times endogenous levels) induced not only cell transformation, but also anchorage-independent growth in soft agar and increased tyrosine phosphorylation of a protein of M(r) 130K. Expression of ornithine decarboxylase antisense RNA was associated with an epithelioid morphology and reduced cell proliferation. Moreover, blocking the endogenous enzyme using specific inhibitor or synthesizing antisense RNA prevented transformation of rat fibroblasts by temperature-sensitive v-src oncogene. Our results imply that the gene encoding ornithine decarboxylase is a proto-oncogene central for regulation of cell growth and transformation.     

Mapping of the protein import machinery in the mitochondrial outer membrane by crosslinking of translocation intermediates.

Mitochondria contain a complex machinery for the import of nuclear-encoded proteins. Receptor proteins exposed on the outer membrane surface are required for the specific binding of precursor proteins to mitochondria, either by binding of cytosolic signal recognition factors or by direct recognition of the precursor polypeptides. Subsequently, the precursors are inserted into the outer membrane at the general insertion site GIP (general insertion protein). Here we report the analysis of receptors and GIP by crosslinking of translocation intermediates and by coimmunoprecipitation. Surface-accumulated precursors were crosslinked to the receptors MOM19 and MOM72, suggesting a direct interaction of preproteins with surface receptors. We identified three novel mitochondrial outer membrane proteins, MOM7, MOM8, and MOM30 that, together with the previously identified MOM38, seem to form the GIP site and are present in the mitochondrial receptor complex.     

“铅树”生成条件的研究

提出了生成“铅树”反应成功的关键是硅酸凝胶的坚固性,找到了较好的硅酸凝胶的制备条件,使该氧化还原平衡移动的反应成功率提高了９０ ％ 以上．     

Effect of actinomycin D on Trypanosoma cruzi

Viable metacyclic forms of T. cruzi, Y strain, treated with an adequate dose of actinomycin D (50 micrograms Act-D/ml/10(7) parasites/ml for 72 h at 28 degrees C) showed the following properties: 1) they lost their ability to replicate in culture medium, in blood and in tissues of normal mice and were no longer able to incorporate tritiated thymidine; 2) they could not penetrate into Vero cells and could not replicate inside normal macrophages; 3) they retained their immunogenicity and the ability to protect mice against a virulent infection; 4) they did not induce histological lesions as described in chronic experimental Chagas' disease.