Induction of anti-EBNA-1 protein by 12-O-tetradecanoylphorbol-13-acetate treatment of human lymphoblastoid cells.

Binding of the Epstein-Barr virus (EBV) nuclear antigen (EBNA-1) to BamHI-C DNA was studied by affinity column chromatography followed by immunoblotting with human serum specific for EBNA-1. Two species of EBNA-1 (68 and 70 kilodaltons) were identified in nuclear extracts of the EBV-positive Burkitt's lymphoma cell line Raji and not in nuclear extracts of the EBV-negative Burkitt's lymphoma cell line BJAB. Both EBNA-1s bound specifically to the region required for EBV plasmid DNA maintenance (oriP) located in the BamHI-C fragment. Upon treatment with 12-O-tetradecanoylphorbol-13-acetate, which activates latent EBV genome in Raji cells, the 68-kilodalton EBNA-1 was uncoupled from binding to EBV oriP. Nuclear extracts from 12-O-tetradecanoylphorbol-13-acetate-treated BJAB cells also uncoupled the binding of both EBNA-1s to oriP. DNA-cellulose column chromatography identified two protein species which competed for and uncoupled the binding of EBNA-1 to oriP. The two cellular competitors we called anti-EBNA-1 proteins had molecular masses of 60 and 40 kilodaltons, respectively. They were not found in nuclear extracts of BJAB cells not activated by 12-O-tetradecanoylphorbol-13-acetate.     

Spectroscopic studies of lipids and biological membranes: carbon-13 and proton magic-angle sample-spinning nuclear magnetic resonance study of glycolipid-water systems.

We have obtained 1H and 13C magic-angle sample-spinning (MAS) nuclear magnetic resonance (NMR) spectra of three glycosyldiacylglycerol-water (1:1, weight ratio) mesophases, at 11.7 T, as a function of temperature, in order to probe lipid headgroup, backbone, and acyl chain dynamics by using natural-abundance NMR probes. The systems investigated were monogalactosyldiacyldiglyceride [MGDG; primarily 1,2-di[(9Z,12Z,15Z)octadec-9,12,15-trienoyl++ +]-3-beta-D-galactopyranosyl- sn-glycerol]; digalactosyldiacyldiglyceride [DGDG; primarily 1,2-di[(9Z,12Z,15Z)octadec-9,12,15-trienoyl++ +]-3- (alpha-D-galactopyranosyl-1-6-beta-D-glactopyranosyl)-sn-glycerol] ; and sulfoquinovosyldiacyldiglyceride [SQDG; primarily 1-[(9Z,12Z,15Z)octadec-9,12,15-trienoyl]-2 -hexadecanoyl-3-(6-deoxyl-6- sulfono-alpha-D-glucopyranosyl)-sn-glycerol]. At approximately 22 degrees C, all three lipid-water systems give well-resoled 13C and 1H MAS NMR spectra, characteristic of fluid, liquid-crystalline mesophases. 13C spin-lattice relaxation times of the headgroup and glycerol backbone carbons of all three materials give, within experimental error, the same NT1 values (approximately 400 ms), implying similar high-frequency motions, independent of headgroup size and charge. Upon cooling, pronounced line broadenings are observed, due to an increase in slow motional behavior. For each lipid, the onset of line broadening is seen with the glycosyl headgroup, glycerol backbone, and the first two or three carbons of the acyl chains. By approximately -20 degrees, all headgroup carbon resonances are broadened beyond detection. Both galactose moieties in DGDG "freeze out" together, implying a rigid-body motion of the disaccharide unit. Upon further cooling, the bulk polymethylene chain resonances in all three systems (in both 13C and 1H MAS) broaden greatly, followed by the olefinic and allylic carbon resonances.(ABSTRACT TRUNCATED AT 250 WORDS)     

Purification and characterization of wheat and pine small basic protein substrates for plant calcium-dependent protein kinase.

A wheat basic protein (WBP) was purified to homogeneity from wheat germ by a protocol involving extraction, centrifugation, batchwise elution from carboxymethylcellulose (CM-52), acidification with trifluoroacetic acid, neutralization and HPLC on a SP5PW cation exchange column. WBP is a 10 kDa protein and is phosphorylated on serine residues by wheat germ Ca(2+)-dependent protein kinase (CDPK). [32P]phosphoWBP exactly comigrates with WBP on SDS-PAGE. WBP does not inhibit either wheat germ CDPK or calmodulin-dependent myosin light chain kinase. Apart from histone H1, WBP is the best endogenous substrate yet found for wheat embryo CDPK. A 12 kDa pine basic protein (PBP) was purified to homogeneity from seeds of stone pine (Pinus pinea L.) by a simple procedure involving batchwise elution from carboxymethylcellulose and cation exchange HPLC. PBP is also a good substrate for CDPK and is phosphorylated on Ser residues. N-terminal sequencing of WBP and PBP revealed that these proteins are homologous to a family of small basic plant proteins having a phospholipid transfer function.     

Hwabyung: The construction of a korean popular illness among korean elderly immigrant women in the United States

The cultural construction of Hwabyung, a Korean culture-bound syndrome, is explored among a sample of 20 elderly Korean immigrant women in the United States. Hwabyung results when distressed emotions associated with the specifically Korean way of perceiving and reacting to intolerable and tragic life situations cause bodily symptoms by interfering with the harmony of Ki (vital energy). Korean elderly immigrants report a broad range of symptoms associated with Hwabyung; they less frequently report the epigastric mass, which had been considered the cardinal symptom by cosmopolitan and traditional medical writers. Hwabyung is treated holistically with psychosocial support from family, spiritual comfort, home and popular remedies, traditional Korean medicine, and biomedical treatments. Hwabyung provides a way of conceptualizing and resolving emotional distress through somatization among Korean elderly immigrant women.     

版纳鱼螈和双带鱼螈核型的比较研究

本文对版纳鱼螈的核型作了观察,并与双带鱼螈进行了比较。两者的核型基本一致,均为2n=42,但版纳鱼螈的NF=62,而双带鱼螈的NF=60;版纳鱼螈的染色体有中部着丝粒、亚中部着丝粒和端部着丝粒三种类型,而双带鱼螈则无亚中部着丝粒的染色体。     

中草药“一口钟”的原植物鉴定及其精油的化学成分

云南,四川等省市售的中草药“一口钟”为蓝桉(Eucalyptus globulus Labill.)的果实.用气相色谱-质谱-计算机联用技术、标准品迭加和毛细管保留指数定性法,对其精油的化学成分进行分析.从分离的65个成分中,鉴定出36个成分,其含量占总组成的93.80％,主要成分是别香树烯(23.37％),1.8-桉叶油素(20.81％)、金合欢醇(9.95％)、α-水芹烯(8.30％)、δ-愈创木烯(5.95％)、δ-蒎烯(4.09％)、β-水芹烯(3.43％)、α-愈创木烯(3.15％)等.     

外源脂肪酸及胆固醇对莱氏衣原体膜糖脂含量的影响

 <正> 单葡萄糖甘油二酯(MGDG)和双葡萄糖甘油二酯(DGDG)是莱氏衣原体膜上主要的极性脂。糖脂的生理功能过去很少研究,至今仍不清楚。近年来实验结果表明,MGDG在膜上容易形成六角形Ⅱ结构,而DGDG则形成脂双层结构。六角形Ⅱ结构的出现与生物膜的生理功能的关系是当前瞩目的研究内容。本文首次研究了外源脂肪酸和胆固酵对莱氏衣原体AIH089菌株膜上糖脂含量的影响。     

Expression of the human retinoblastoma gene product pp110RB in insect cells using the baculovirus system

The product of the retinoblastoma susceptibility gene (RB) was overproduced in cultured insect cells using the baculovirus expression system. Upon insertion of the cloned human RB complementary DNA sequence into the viral genome downstream of the promoter of the polyhedrin gene, full-length RB protein with an apparent molecular weight of 110,000 was expressed in the insect cells. This protein was found to be phosphorylated, located in the nuclei of the infected cells, and immunologically indistinguishable from pp110RB of human cells as assayed by several anti-RB antibodies. Following cell disruption and a one-step immunoaffinity chromatographic purification, 6-12 mg of soluble pp110RB with approximately 95% purity were obtained per liter of infected suspension culture. Characterization of the two known biochemical properties of RB protein showed that this purified protein from insect cells behaved similarly to the authentic human pp110RB. First, it bound to DNA, and second, it could form a specific complex with SV40 T antigen in vitro. Prompt translocation of the protein from cytoplasm to nucleus after microinjection further indicated that the purified RB protein may be active. The availability of soluble, intact, and presumably active pp110RB in large quantity represents a significant advance for studying the biochemical and biophysical properties of the RB gene product as well as its potential biological function in cancer suppression.     

Growth inhibition of selected food-borne bacteria, particularly Listeria monocytogenes, by plant extracts

C hung , K.-T., T homasson , W.R. & W u -Y uan , C.D. 1990. Growth inhibition of selected food-borne bacteria, particularly Listeria monocytogenes , by plant extracts. Journal of Applied Bacteriology 69 , 498–503.
Six extracts from Chinese medicinal plants: Tin Men Chu, Sey Lau Pai, Siu Mao Heung, Bak Tao Yung, Kam Chin Chiu and Liao Ya, were tested for their inhibitory effect on selected food-borne bacteria by the well assay technique. Among them, Tin Men Chu, Siu Mao Heung and Sey Lau Pai inhibited the growth of Staphylococcus aureus, Klebsiella pneumonia, Escherichia coli, Shigella flexneri, Streptococcus faecalis, Salmonella paratyphi, Salm. enteritidis, Enterobacter aero-genes, Pseudomonas fluorescens, Proteus vulgaris, Alcaligenes faecalis , and three strains of Listeria monocytogenes . Two of these three extracts, Tin Men Chu and Siu Mao Heung, suppressed the growth of L. monocytogenes Scott A in cabbage juice. This inhibition was prevented by the addition of protein but not sodium chloride. Plant extracts show potential to control the growth of food-borne bacteria.     

DNA Segments Sensitive to Single-Strand-Specific Nucleases Are Present in Chromatin of Mitotic Cells

It was observed before that DNAin situin chromatin of mitotic cells is more sensitive to denaturation than DNA in chromatin of interphase cells. DNA sensitivity to denaturation, in these studies, was analyzed by exposing cells to heat or acid and using acridine orange (AO), the metachromatic fluorochrome which can differentially stain double-stranded (ds) vs single-stranded (ss) nucleic acids, as a marker of the degree of DNA denaturation. However, without prior cell treatment with heat or acid no presence of single-stranded DNA in either mitotic or interphase cells was detected by this assay. In the present experiments we demonstrate that DNAin situin mitotic cells, without any prior treatment that can induce DNA denaturation, is sensitive to ss-specific S1 and mung bean nucleases. Incubation of permeabilized human T cell leukemic MOLT-4, promyelocytic HL-60, histiomonocytic lymphoma U937 cells, or normal PHA-stimulated lymphocytes with S1 or mung bean nucleases generated extensive DNA breakage in mitotic cells. DNA strand breaks were detected using fluorochrome-labeled triphosphonucleotides in the reaction catalyzed by exogenous terminal deoxynucleotidyl transferase. Under identical conditions of the cells’ exposure to ss-specific nucleases, DNA breakage in interphase cells was of an order of magnitude less extensive compared to mitotic cells. The data indicate that segments of DNA in mitotic chromosomes, in contrast to interphase cells, may be in a conformation which is sensitive to ss nucleases. This may be a reflection of the differences in the torsional stress of DNA loops between interphase and mitotic chromatin. Namely, greater stress in mitotic loops may lead to formation of the hairpin-loop structures by inverted repeats; such structures are sensitive to ss nucleases. The present method of detection of such segments appears to be more sensitive than the use of AO. The identification of mitotic cells based on sensitivity of their DNA to ss nucleases provides an additional method for their quantification by flow cytometry.