Possible involvement of ethylene-activated {beta}-cyanoalanine synthase in the regulation of cocklebur seed germination

A possible involvement of ß-cyanoalanine synthase(CAS: EC 4.4.1.9 [EC] ) in germination processes of seeds was demonstratedusing pre-soaked upper seeds of cocklebur (Xanthium pennsylvanicumWallr.). Pretreatment in anoxia not only with KCN but also cysteine,as the substrates for CAS, stimulated the subsequent germinationof cocklebur seeds in air. However, the effect of cysteine wasmanifested even in air when applied together with C₂H₄, andits effect was further enhanced in combination with KCN. Thegermination-stimulating effect of KCN was intensified by C₂H₄only when 0₂ was present. In contrast, serine, another substrateof CAS, was effective in air only when combined with C₂H₄ and/orKCN. The addition of cysteine greatly reduced the cyanogenicglycoside content of seeds, but increased HCN evolution. Onthe other hand, glutathione did not have any effect on cockleburseed germination, HCN evolution or bound cyanogen content, suggestingthat cysteine is not acting as a reducing reagent. It is suggestedthat CAS regulates the process of cocklebur seed germinationby the dual action of enlarging the pool of amino acids andsupplying sulphydryl bases, the latter being more determinatelyimportant. Serine is effective only via the former action, whilecysteine would act via both. Key words: Cyanide, cyanogenic glycoside, ß-cyanoalanine synthase, seed germination, Xanthium pennsylvanicum     

Potentiation by BL191 of differentiation of neuroblastoma cells induced by dibutyryl cAMP and prostaglandin E1

BL191, a newly developed phosphodiesterase inhibitor, markedly potentiated a differentiation of neuroblastoma cell clones (Neuro2a, NS-20Y, and N1E115) induced by dibutyryl cyclic adensoine 3′:5′-monophosphate(dibutyryl cAMP) and prostaglandin E₁ (PGE₁). BL191 (1 mM) inhibited DNA synthesis more strongly when used together with PGE₁ (0.5 μg/ml) and dibutyryl cAMP (0.5 mM) than papaverine (1.6 μg/ml) alone did. The inhibition rates of DNA synthesis were 72.5% for N1E-115, 75.3% for Neuro2a, and 82.5% for NS-20Y. After the treatment with BL191. PGE₁, and dibutyryl cAMP for 48 h all of three cell lines became enlarged and flattened, and extended long processes. The specific activities of choline acetyl transferase (EC 2.3.1.9) of NS-20Y and dopamine β-hydroxylase (EC 1.14.17.1) of N1E-115 increased about 3-fold as compared to the controls. The tumorigenicities of Neuro2a and N1E-115 cells were decreased, but not of NS-20Y. These data suggest the heterogenous responsiveness in neuroblastoma cells to drug treatment.     

Reaction of some D-glucobioses with 2,2-dimethoxypropane

Laminarabiose, cellobiose, and gentiobiose were acetonated with 2,2-dimethoxy-propane under various conditions. Two isopropylidene acetals in which the reducing D-glucose residue had the furanoid form were obtained from laminarabiose, and two, in which the reducing D-glucose residue formed the acyclic dimethyl acetal, from cellobiose. Gentiobiose gave both types of isopropylidene compound.     

Glycoprotein galactosyltransferase activity in synaptic junctional complexes isolated from rat forebrain

A synaptosomal plasma membrane fraction and its junctional and nonjunctional subfractions were isolated and analyzed for glycoprotein galactosyltransferase activity. The nonjunctional components fraction had the highest specific activity in the presence of exogenous acceptor, suggesting an enrichment of enzyme in this fraction. The synaptic junctional complex fraction had the highest specific activity in the absence of added acceptor, suggesting that there is a relative enrichment of endogenous acceptors for this galactosyltransferase within the synaptic junctional complex.Presented in part at the 6th meeting of the Society of Neuroscience, Toronto, Ontario, November, 1976 (Goodrum, Bosmann, and Tanaka, 1976)     

Purification and properties of a membrane-bound aldehyde dehydrogenase from rat liver microsomes

A membrane-bound aldehyde dehydrogenase was solubilized from rat liver microsomes and purified about 150-fold by chromatography on ω-aminohexyl- and 5′-AMP-Sepharose columns with a recovery of about 40%. The purified enzyme was homogeneous upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis and its monomeric molecular weight was estimated to be 51,000. In aqueous solution, it existed as large, polymeric aggregates. Its activity towards straight-chain aliphatic aldehydes increased as their carbon chain length was increased at least up to dodecanal, whereas aldehyde dehydrogenase in the cytosolic fraction of rat liver was most active with hexanal as substrate.     

Studies of pesticides effects on Chlorella metabolism II. Effect of DCMU on galactolipid metabolism

DCMU (N'-(3,4-dichlorophenyl)-N, N-dimethylurea) was testedfor effects on the metabolism of galactolipids in Chlorellaand chloroplasts isolated from higher plants. In Chlorella,DCMU affected galactolipid synthesis in the light more thanthat of other lipids, but it showed no effect on lipid synthesisin the dark. DCMU did not affect the turnover of galactolipidsin the light. In vitro studies using ¹⁴C-acetate or ¹⁴C-UDP-galactoseas a precursor showed that DCMU had no effect on the synthesisof gross lipid or galactolipids in chloroplasts isolated fromhigher plants. The significance of these observations are discussed. (Received September 21, 1974; )     

Anatomy-based prediction method for determining ipsilateral lung doses in postoperative breast radiation therapy assisted by diagnostic computed tomography images

BackgroundThis study aimed to investigate whether ipsilateral lung doses (ILDs) could be predicted by anatomical indexes measured using diagnostic computed tomography (CT) prior to the planning stage of breast radiation therapy (RT).Materials and methodsThe thoracic diameters and the length of lines drawn manually were measured on diagnostic CT images. The parameters of interest were the skin maximum lung distance (sMLD), central lung distance (CLD), Haller index (HI), and body mass index (BMI). Lung dose-volume histograms were created with conformal planning, and the lung volumes receiving 5–40 Gy (V5–V40) were calculated. Linear regression models were used to investigate the correlations between the anatomical indexes and dose differences and to estimate the slope and 95% confidence intervals (CIs).ResultsA total of 160 patients who had undergone three-dimensional conformal RT after breast-conserving surgery were included. Univariable analysis revealed that the sMLD (p < 0.001), CLD (p < 0.001), HI (p = 0.002), and BMI (p < 0.001) were significantly correlated with the V20. However, multivariable analysis revealed that only the sMLD (slope: 0.147, p = 0.001, 95% CI: 0.162–0.306) and CLD (0.157, p = 0.005, 0.048–0.266) were strongly correlated with the V20. The p-value for the sMLD was the lowest among the p-values for all indexes, thereby indicating that the sMLD had the best predictive power for ILD.ConclusionssMLD and CLD are anatomical markers that can be used to predict ILD in whole breast RT. An sMLD > 20.5 mm or a CLD > 24.3 mm positively correlated with a high ILD.     

A new technique to expand human mesenchymal stem cells using basement membrane extracellular matrix

Mesenchymal stem cells (MSC) show a very short proliferative life span and readily lose the differentiation potential in culture. However, the growth rate and the proliferative life span of the stem cells markedly increased using tissue culture dishes coated with a basement membrane-like extracellular matrix, which was produced by PYS-2 cells or primary endothelial cells. Furthermore, the stem cells expanded on the extracellular matrix, but not those on plastic tissue culture dishes, retained the osteogenic, chondrogenic, and adipogenic potential throughout many mitotic divisions. The extracellular matrix had greater effects on the proliferation of MSC and the maintenance of the multi-lineage differentiation potential than basic fibroblast growth factor. Mesenchymal stem cells expanded on the extracellular matrix should be useful for regeneration of large tissue defects and repeated cell therapies, which require a large number of stem or progenitor cells.