Antioxidant Activity of Antiviral Proteins from Celosia cristata

The antioxidant activity test of Celosia cristata antiviral proteins (CCP-25 and CCP-27) using ferric reducing antioxidant power (FRAP) assay in vitro indicated that these proteins are strong antioxidants. The increase in activities of redox-enzymes such as peroxidase, catalase and polyphenol oxidase on tobacco mosaic virus (TMV) inoculation of test plants, was inhibited when plants were treated with CCP-25 before TMV inoculation. The activity of phenylalanine ammonia lyase, involved in biosynthesis of antioxidative compounds was also inhibited. This is the first ever report where plant antiviral proteins have been shown to have strong antioxidative property. A possible correlation between antioxidant activity of CCPs and their antiviral activity is speculated.     

Shock Wave Application to Cell Cultures

Shock waves nowadays are well known for their regenerative effects. Basic research findings showed that shock waves do cause a biological stimulus to target cells or tissue without any subsequent damage. Therefore, in vitro experiments are of increasing interest. Various methods of applying shock waves onto cell cultures have been described. In general, all existing models focus on how to best apply shock waves onto cells.However, this question remains: What happens to the waves after passing the cell culture? The difference of the acoustic impedance of the cell culture medium and the ambient air is that high, that more than 99% of shock waves get reflected! We therefore developed a model that mainly consists of a Plexiglas built container that allows the waves to propagate in water after passing the cell culture. This avoids cavitation effects as well as reflection of the waves that would otherwise disturb upcoming ones. With this model we are able to mimic in vivo conditions and thereby gain more and more knowledge about how the physical stimulus of shock waves gets translated into a biological cell signal (“mechanotransduction").     

Histochemical Method for Detecting Nitric Oxide Synthase Activity in Cell Cultures

NADPH diaphorase histochemistry has been used extensively for detecting nitric oxide synthase (NOS) activity in various cell types including neuronal cell bodies, vascular endothelium, cells of the immune system and epithelial cells. The use of the diaphorase technique in cell cultures to study the induction of NOS has not been investigated. In this paper we report the use of diaphorase histochemistry as a good marker for the detection of NOS activity in cultured cells. This technique can be used in conjunction with other established techniques to determine the presence and activity of NOS in cultured cells.     

Effect of Latrotoxin-Like Protein on Spontaneous Postsynaptic Activity in Hippocampal Cell Cultures

-Latrotoxin, an active component of black widow spider venom, is known to enhance spontaneous neurotransmitter release. In cultured rat hippocampal neurons, we studied the effects of latrotoxin-like protein (protein purified from the bovine brain and exhibiting some functional properties similar to those of -latrotoxin) on spontaneous GABA-ergic inhibitory currents (IPSC). Latrotoxin-like protein was found to dramatically increase the frequency of spontaneous IPSC recorded in cell cultures of dissociated hippocampal neurons in the presence of tetrodotoxin. Possible mechanisms of the action of latrotoxin-like protein on transmitter release are discussed.     

Cell Survival Characteristics and Choline Acetyltransferase Activity in Motor Neurone-Enriched Cultures from Chick Embryo Spinal Cord

The effect of muscle extract on cell survival and choline acetyltransferase (ChAT) activity in cultures of enriched cholinergic neurones from 7-day chick embryo spinal cord was examined. When neurones were grown on hydrated collagen gels, considerable cell survival and ChAT activity were obtained even in the absence of tissue extract. These parameters were stimulated twofold in the presence of skeletal muscle extract but not liver or skin extracts. The cholinergic neurotrophic activity was found to be heat- and trypsin-sensitive, nondialysable, and to act in the virtual absence of glial cells. These data are consistent with a retrogradely acting motor neurone trophic activity.     

Protoplast Cultures from Cell Suspensions of Daucus carota

Protoplasts, enzymatically isolated from cell suspension cultures of Daucus carota, have been grown in small Petri-dishes. After enzyme treatment and washing the protoplasts were plated in agar media. Growth and divisions were viewed through the bottom of the Petri-dishes with a light microscope. Different osmotic stabilizers were tested with respect to their ability to promote wall formation and growth of the protoplasts. Combinations of sucrose, sorbitol and “Modopeg” gave the best results. Electron micrographs of cultured protoplasts revealed normal as well as abnormal nuclear conditions.     

Antigenicity of Influenza Vaccine from Bovine Cell Cultures

An experimental vaccine prepared from influenza virus strains propagated in bovine kidney cell cultures, purified by zonal centrifugation, and further treated with ether was studied in man for the incidence of clinical reactions and hemagglutination-inhibition antibody levels induced. The results were equivalent to those obtained in a simultaneous study made with a commercially licensed influenza vaccine derived from viruses propagated in the embryonated egg and also purified by zonal centrifugation, but not treated with ether. Comparison of the macromethod and the micromethod for determination of hemagglutination-inhibition antibody titers revealed that lower initial titers and lesser increments in antibody levels following vaccination were obtained by the microtechnique.     

Evaluation of the Hydroxynitrile Lyase Activity in Cell Cultures of Capulin （Prunus serotina）

Enzymatic preparations obtained from young plants and cell cultures of capulin were screened for hydroxynitrile lyase activity. The threeweek old plants, grown under sterile conditions, were used to establish a solid cell culture. Crude preparations obtained from this plant material were evaluated for the transformation of benzaldehyde to the corresponding cyanohydrin (mandelonitrile). The results show that the crude material from roots, stalks, and leaves of young plants and calli of roots, stalks, internodes and petioles biocatalyzed the addition of hydrogen cyanide (HCN) to benzaldehyde with a modest to excellent enantioselectivity.     

Effect of Coronatine on Ethylene Release and ATPase Activity of Tomato Cell Cultures

The effects of the phytotoxin coronatine formed by pathovars of Pseudomonas syringae on coronatine sensitive cell cultures of Lycopersicon peruvianum and Lycopersicon esculentum were investigated. The studied parameters were ethylene release, activity of membrane-bound ATPase and vitality using the TTC test. The cells of L. esculentum responded with an increase, the cells of L. peruvianum with a decrease of ethylene formation after application of different coronatine concentrations. These results indicate that the effect on ethylene release is not the primary effect of the toxin. The activity of membrane-bound ATPase was not affected by coronatine.     

Nucleoside-catabolizing Enzymes in Mycoplasma-infected Tumor Cell Cultures Compromise the Cytostatic Activity of the Anticancer Drug Gemcitabine

The intracellular metabolism and cytostatic activity of the anticancer drug gemcitabine (2′,2′-difluoro-2′-deoxycytidine; dFdC) was severely compromised in Mycoplasma hyorhinis-infected tumor cell cultures. Pronounced deamination of dFdC to its less cytostatic metabolite 2′,2′-difluoro-2′-deoxyuridine was observed, both in cell extracts and spent culture medium (i.e. tumor cell-free but mycoplasma-containing) of mycoplasma-infected tumor cells. This indicates that the decreased antiproliferative activity of dFdC in such cells is attributed to a mycoplasma cytidine deaminase causing rapid drug catabolism. Indeed, the cytostatic activity of gemcitabine could be restored by the co-administration of tetrahydrouridine (a potent cytidine deaminase inhibitor). Additionally, mycoplasma-derived pyrimidine nucleoside phosphorylase (PyNP) activity indirectly potentiated deamination of dFdC: the natural pyrimidine nucleosides uridine, 2′-deoxyuridine and thymidine inhibited mycoplasma-associated dFdC deamination but were efficiently catabolized (removed) by mycoplasma PyNP. The markedly lower anabolism and related cytostatic activity of dFdC in mycoplasma-infected tumor cells was therefore also (partially) restored by a specific TP/PyNP inhibitor (TPI), or by exogenous thymidine. Consequently, no effect on the cytostatic activity of dFdC was observed in tumor cell cultures infected with a PyNP-deficient Mycoplasma pneumoniae strain. Because it has been reported that some commensal mycoplasma species (including M. hyorhinis) preferentially colonize tumor tissue in cancer patients, our findings suggest that the presence of mycoplasmas in the tumor microenvironment could be a limiting factor for the anticancer efficiency of dFdC-based chemotherapy. Accordingly, a significantly decreased antitumor effect of dFdC was observed in mice bearing M. hyorhinis-infected murine mammary FM3A tumors compared with uninfected tumors.     

Sequential Isolation of Superoxide Dismutase and Ajmaline from Tissue Cultures of Rauwolfia serpentinaBenth

Two biologically active compounds, the enzyme superoxide dismutase (EC 1.15.1.1) and the anti-arhythmic indole alkaloid ajmaline, were isolated from a callus culture of Rauwolfia serpentinaBenth. Sequential isolation of biologically active compounds by metal–chelate affinity chromatography followed by azoadsorbent affinity chromatography allowed us to obtain highly purified products. The yields of superoxide dismutase and ajmaline were 180 mg/kg biomass and 16.5 g/kg dry weight, respectively.     

1-甲基-4-苯基-吡啶盐致多巴胺能细胞系MES23.5的死亡机制

通过测定环境毒素1-甲基-4-苯基-吡啶盐(MPP )作用于多巴胺能细胞系MES23．5后细胞存活率的变化及细胞线粒体膜电位(△ψM)、活性氧(ROS)、羟自由基、超氧化物岐化酶(SOD)的变化,发现MPP^ 作用于多巴胺能细胞系MES23．5,可导致细胞存活率显著性减少,浓度达到200mol／L以上后,细胞存活率的下降呈时间与MPP^ 浓度依赖;以200μmol/L MPP^ 作用细胞6∽48h后,△ψM逐渐下降、ROS、羟自由基逐渐增加,48h后SOD开始显著性减少。结果表明早期线粒体能量代谢障碍和膜电位变化导致ROS(尤其是羟自由基)含量增加是MPP^ 导致多巴胺能细胞氧化应激的原因,而细胞内自由基的清除机制受损,则最终导致细胞变性死亡。     

Characterization of Aluminum and Manganese Tolerant Cell Lines Selected from Carrot Cell Cultures

Two carrot cell lines tolerant to aluminum and manganese wereselected from suspension cultures by subculturing cells in anexcessive amount of AlCl₃3 or MnCl₂ forseveral months, and theirproperties were investigated. The Al-tolerant cell line wasnot tolerant to Mn, and the Mn-tolerant cell line was not tolerantto Al. A cell line tolerant to both Al and Mn was obtained bysubculturing the Al-tolerant cell line in the presence of excessMn. Both the Al- and the Mn-tolerant lines had many more uniform,free cells and only a few small cell aggregates in comparisonto the nonselected parental cell line. Of the cells examinedat metaphase, about 50% of the selected cells had a chromosomenumber of 26 and about 50% of the nonselected cells had 28;a significant difference in the chromosome numbers of the twolines. The acquired Al-tolerance was stable because selectedcells retained their tolerance after prolonged subculture inthe absence of Al. The Al-tolerant cell line selected underthe stress of AlCl₃ was not tolerant to Al-EDTA, but was tolerantto gallium chloride, gallium belonging to the same group asAl in the Periodic Table. Aluminum gels, which formed in the medium after the additionof AlCl₃, gradually became soluble as the Al-tolerant cell culturegrew. This suggests that some chelating substance(s) releasedfrom the cells dissolves the Al-gels in the medium. (Received January 20, 1983; Accepted March 31, 1983)     

喷昔洛韦体外抗疱疹病毒活性的研究

为评价新合成的喷昔洛韦的细胞毒性和抗疱疹病毒活性,通过观察病毒感染细胞的CPE、病毒滴度、抗病毒指数,从而判定喷昔洛韦的抗疱疹病毒作用.结果发现喷昔洛韦对HEL细胞、Hep-2细胞的半数中毒浓度(TD\-50)分别为105.2μg/mL和85.1μg/mL;对HSV-1、HSV-2、VZV、HSV-1吴株的平均半数抑制浓度(IC\-50)分别为21.78μg/mL、20.15μg/mL、23.19μg/mL和17.87μg/mL,对各毒株的治疗指数分别为5.84、6.31、5.49和7.11.故喷昔洛韦是一种有效体外抗疱疹病毒药物.