活性氧对巨噬细胞呼吸爆发影响及云芝多糖的保护作用

用化学发光法观察到叔丁基氢过氧化物对培养的小鼠腹腔巨噬细胞呼吸爆发有强烈的抑制作用。云芝多糖经腹腔注射后,能增强巨噬细胞呼吸爆发功能对叔丁基氢过氧化物损伤的抵抗力。云芝多糖处理的巨噬细胞谷胱甘肽过氧化物酶基础活力显著提高,在叔丁基氢过氧化物作用下,云芝多糖处理的巨噬细胞仍有较高的谷胱甘肽过氧化物酶活力。说明巨噬细胞的免疫功能与谷胱甘肽过氧化物酶活力有关,非特异性免疫多糖可提高细胞抗氧化能力,减轻活性氧损伤作用。     

A fibroblast-derived tumor cytotoxic factor/F-TCF (hepatocyte growth factor/HGF) has multiple functions in vitro.

We previously demonstrated that a tumor cytotoxic factor(F-TCF) purified from the culture broth of human embryonic lung diploid fibroblast, IMR-90 cells was one of the human hepatocyte growth factors (hHGFs). In the present report, we demonstrate its biological functions. F-TCF showed moderate cytotoxicity on human tumor cell lines KB, BG-1, MCF-7 and Hs913 T, and strong cytotoxicity on mouse tumor cell lines Sarcoma 180, Meth A sarcoma and P388. On the contrary, F-TCF was a potent mitogen not only for adult rat hepatocytes, but also for human endothelial cells, HUVEC and human melanocytes. Moreover, F-TCF induced the differentiation of premyelocyte leukemia, HL-60 cells into morphologically granulocyte-like cells. These biological functions suggest that F-TCF is an effector molecule responsible for inflammation and repair in injured tissues including tumor and liver.     

Blue Light-Induced Phototropic Response and the Intracellular Photoreceptive Site in Adiantum Protonemata

Blue light-induced phototropism in Adiantum protonemata wasinvestigated with microbeam irradiation. Brief irradiation withblue light effectively induced a phototropic response when itwas applied to a half-side of the apical 200d µm regionof a protonema. The phototropic response was partly reversedby the subsequent far-red light irradiation but the full reversalof the response was not observed even when the fluence of far-redlight was increased. In the far-red reversible part of the response,blue/far-red photoreversibility was repeatedly observed. Thus,both phytochrome and a blue light-absorbing pigment (other thanphytochrome) seem to be involved in the blue light-induced phototropicresponse in Adiantum protonemata. Furthermore, detailed studiesof the far-red light effect on the fluence-response curve forblue lightinduced phototropism revealed that the concomitantmediation by the two receptors was limited to the response inthe relatively higher fluence range of blue light and that theblue light-absorbing pigment alone was responsible in the lowerfluence range. In the higher fluence range, the response mediatedby the blue light-absorbing pigment became saturated and thephytochrome response became evident, indicating a differencein the sensitivities of the two receptor pigments to blue light. When various regions of half-sides of protonemata were irradiatedwith a blue microbeam of 10 µm width, irradiation at theapical 5–25 µm region was most effective both forphytochrome- and blue light-absorbing pigment-mediated response,indicating that the site of blue light perception is almostidentical for each response. (Received July 14, 1986; Accepted September 26, 1986)     

Specific binding of three neurotoxins with phospholipase A2 activity to synaptosomal membrane preparations from the guinea pig brain

Snake presynaptic toxins such as crotoxin, β-bungarotoxin and taipoxin block neuromuscular transmission through inhibiting the release of acetylcholine by their phospholipase A₂ activities. On the other hand, many other phospholipase A₂s show little neurotoxicity. It is likely that the difference lies in whether high affinity binding to nerve cell membranes exists or not. To test this idea, crotoxin, β-bungarotoxin and taipoxin were first radioactively labeled with Na(¹²⁵I) without loss of their neurotoxicity. Using the radioactive toxins we have found that each of the three showed specific binding to synaptosomal membranes from guinea pig brain. In contrast, we could not detect specific binding of a non-neurotoxic pancreatic phospholipase A₂. Crotoxin and taipoxin, but not β-bungarotoxin, also bound specifically to membrane preparation from other tissues. The binding of each toxin was not greatly affected by the other two toxins. The photoaffinity labeling technique has been used to obtain further information about the components which bind crotoxin. For this purpose, (¹²⁵I) crotoxin was derivatized with N-hydroxysuccinimidyl-4-azidobenzoate. Autoradiographic analysis of the membranes following photoirradiation in the presence of the modified crotoxin revealed that an 85K dalton component was preferentially covalently conjugated with the crotoxin analogue in a specific manner.     

The human alpha-fetoprotein gene. Sequence organization and the 5' flanking region

The human alpha-fetoprotein (AFP) gene was isolated into three overlapping clones in bacteriophage lambda vectors and its sequence organization analyzed by restriction endonuclease mapping and nucleotide sequencing. The human AFP gene is about 20 kilobase pairs long and contains 15 exons and 14 introns. The overall organization of the human AFP gene is similar to that of the mouse AFP gene, with all but two exons showing identical sizes. Nucleotide sequences at all exon/intron junctions display similarity to the consensus boundary sequence (Breathnach, R., and Chambon, P. (1981) Annu. Rev. Biochem. 50, 349-383), with the GT-AG rule applied to the splicing point. The cap site maps 44 nucleotides upstream from the translation initiation site. The "TATA box" is located 27 nucleotides upstream from the putative cap site and is flanked by sequences with dyad symmetry. The TATA box can thus be placed in the loop portion of a possible stem-loop structure formed by intrastrand base-pairing. Other characteristic nucleotide sequences in the 5' flanking region include a CCAAC pentamer, a 14-base pair (bp) enhancer-like sequence, and a 9-bp sequence homologous to the glucocorticoid responsive element. A long (90 bp) direct repeat and several alternating purine/pyrimidine sequences are also present in the 5' flanking region. A 736-bp sequence of the 5' flanking region adjacent to the cap site of the human AFP gene shows a 61% similarity with the corresponding region of the mouse AFP gene. There are two Alu family sequences and two poly(dT-dG) repeats in the human AFP gene that show different distribution patterns from those in the mouse AFP gene.     

Differential expression of 2′∶3′-cyclic nucleotide 3′-phosphodiesterase in cultured central,peripheral, and extraneural cells

The relative levels of the central nervous system myelin marker enzyme 2:3-cyclic nucleotide 3-phosphodiesterase (EC 3.1.4.37, CNPase) were determined in neuroblastoma, astrocyte, oligodendrocyte and Schwann cell cultures and in freshly isolated human lymphocytes and platelets. The highest specific activities were associated with the cells that elaborate myelin membrane in the central and peripheral nervous system, oligodendrocytes and Schwann cells, respectively. Antiserum to bovine CNPase recognized both CNP1 and CNP2 in CNS myelin and human oligodendroglioma. In addition, a 53,000 dalton protein was evident on autoradiographs of immunoblotted PNS myelin and human oligodendroglioma proteins. Cultured rat oligodendrocyte, C₆ and mouse NA neuroblastoma CNPase appear to share common determinants with the corresponding normal rat CNS enzyme.     

辣椒四个品种的核型研究

本文对我国栽培辣椒Capsicum annuum L.的四个品种即汉川椒、华椒一号、牛角椒和二金条进行了核型分析,其染色体数目均为2n=2x=24,核型公式均为2n=24=20m+2sm+2st,但汉川椒和华椒一号具一对随体,牛角椒和二金条具两对随体。本文还对它们的进化关系进行了讨论。