Conversion of DOPA to tetrahydroisoquinolines and stizolobic acid in a callus culture of Stizolobium hassjoo

Isolation and identification of l-3-carboxy-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline and l-1-methyl-3-carboxy-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline from seeds and callus of S. hassjoo are described. Administration of [β-¹⁴C]-labelled DOPA to a callus culture of this legume resulted in the incorporation of radioactivity into l-3-carboxy-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, l-1-methyl-3-carboxy-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline and stizolobic acid, which was confirmed by constant specific radioactivity after co-crystallization with authentic samples of each compound.     

Depside as potent inhibitor of prostaglandin biosynthesis: a new active site model for fatty acid cyclooxygenase

Forty depsides and depsidones, the esters of phenolcarboxylic acids, were examined for their inhibitory effect against prostaglandin biosynthesis with rabbit renal microsomes. 4-0-Methylcryptochlorophaeic acid was the most active inhibitor so far tested and its IC50 value was 0.34 muM. Kinetic investigation has shown that this depside acts competitively with respect to arachidonic acid as most of the non - steroidal antiinflammatory drugs. X-Ray analysis has revealed that 4-0-methylcryptochlorophaeic acid maintains its rigid conformation by forming a strong hydrogen bond between the hydroxyl and methoxyl groups. Comparison of CPK models between 4-0-methylcryptochlorophaeic acid and non-steroidal antiinflammatory drugs revealed that the carboxyl group and the two rings of these drugs are almost superimposable to those of the depside. This finding led us to propose a new active site model based on the three dimentional structure of the depside.     

Analysis of dorsal pitting in the os publis in an extensive sample of modern American females

Pubic bones from 486 modern American females between the ages of 13 and 99 were studied in an attempt to explore the relationship between the degree of dorsal pitting and the following variables: (1) number of full term pregnancies, (2) inteval since last pregnancy, (3) age of decedent.A statistical association was found between the number of full term pregnancies and the degree of dorsal pitting. However, the correlation is not strong; 17 females reported as being nulliparous have "medium to large" dorsal changes whereas 22 females having from one to five full term pregnancies have an absence of dorsal changes. Females who had their last child 15 or more years prior to death are more apt to have "medium to large" dorsal changes than are females who have more recently given birth. This effect appears to be independent of the number of full term pregnancies, but is probably related to age. When the data are analyzed by multiple regression analaysis, it is found that age and number of pregnancies are most important in predicting the degree of pitting and the effect of the interval on pitting is not significant. Age is found to be an important variable independent of the number of full term pregnancies. In nulliparas, an absence of dorsal pitting is far more frequently found in females younger than 30 than in those over 30.     

Phosphatidyl inositol: myo-Inositol exchange enzyme from rat liver: Partial purification and characterization

The enzyme which catalyzes CDP-diglyceride-independent incorporation of myo-inositol into phosphatidyl inositol was solubilized from rat liver microsomes by sodium cholate and was partially purified by ammonium sulfate fractionation and sucrose density gradient centrifugation. Addition of phospholipids during purification and assay procedures prevented irreversible loss of the enzyme activity to some extent. The resulting preparation contained about 3.7% of the protein and 35% of the original activity of the microsomal fraction. The activity of the enzyme preparation was strongly enhanced by addition of phosphatidyl inositol. The enzyme required Mn²⁺ for activity. The K_m for myo-inositol was 4 × 10^?5m. The pH optimum was 7.4. The activity was inhibited by thiol-reactive reagents and also to some extent by inosose-2 but not by scyllitol. Phosphorus-containing acidic substances such as acidic phospholipids and nucleotides were generally inhibitory. It was found that the preparation catalyzed liberation of inositol moiety from phosphatidyl inositol in a manner dependent on the concentration of free myo-inositol and also on Mn². The K_m of this reaction for free myo-inositol was estimated to be 7 × 10^?5m. This result indicates that CDP-diglyceride-independent incorporation, which has been assumed to show inositol exchange reaction, actually represents an exchange reaction between the myo-inositol moiety of phosphatidyl inositol and free myo-inositol. Phosphatidyl choline and phosphatidyl ethanolamine did not play a role as acceptor of the exchange reaction.     

Relationship between hormone content and autonomy in various autonomous tobacco cells cultured in suspension

Various autonomous cultured tobacco cells including crown gallwere examined for their contents of growth regulators by meansof Avena curvature test, cell-division induction test, and tobaccopith callus test. The crown gall cells derived from cv. Hicks produced auxin andcytokinin in the high levels of 300–500 µg IAA equivalentsand 40–80 µg kinetin equivalents per kg, respectively.The major auxin was identified as indole-3-acetic acid basedon mass spectrometry and gas chromatography. These cells alsoproduced methyl indole-3-acetate as a minor component. One ofthe cytokinins was identified as ribosyl-trans-zeatin by meansof both gas chromatography-mass spectrometry and high performanceliquid chromatography. Auxin and cytokinin activities were not detected in the followingthree suspension cultured tobacco cells: cells requiring neithercytokinin nor auxin derived from the callus of N. tabacum cv.Bright Yellow and cells requiring auxin but not cytokinin derivedfrom the calluses of cv. Bright Yellow and cv. Hicks. Theirauxin and cytokinin contents per kg were less than 1 µgIAA equivalent and less than 0.1 µg kinetin equivalent,respectively. The results obtained in this study indicate that enhanced hormonalcontent is not the only reason for autonomous growth. (Received August 16, 1979; )     

Two new coumarins in Boenninghausenia albiflora

Two new isomeric coumarins were isolated from leaves of Boenninghausenia albiflora Reichb. Their structures were elucidated as (E)-7-hydroxy-6-(3-hydroxy-3-methyl-1-butenyl)-2(H)-1-benzpyran-2-one and (Z)-7-hydorxy-6-(3-hydroxy-3-methyl-1-butenyl)-2(H)-1-benzopyran-2-one.     

Effect of auxins on the formation of ubiquinone by tobacco plant cells in suspension culture

Ubiquinone (UQ) formation in BY-2 tobacco cells was especially promoted by a high concentration of 2,4-D. 2,4,5-T, MCP and NAA also promoted UQ formation in these cells. The UQ content in the cells cultured at high concentrations of 2,4-D was higher than that of controls throughout the culture period. The addition of 2,4-D at an early period in cell growth was very effective in promoting UQ formation, but addition at the stationary phase was ineffective. Cell growth was improved by adding phosphate to the medium but UQ content was decreased. UQ content decreased slowly during subculturing, whereas cell growth recovered gradually.     

Control of the production of orthophosphate repressible extracellular enzymes in Neurospora crassa

Molecular Genetics and Genomics - The abilities of purine- and pyrimidinerequiring mutants to produce six orthophosphate repressible extracellular enzymes, alkaline phosphatase,...     

A tryptic peptide from beta-casein depresses protein synthesis and degradation and enhances ureogenesis in primary cultures of rat hepatocytes

1. A peptide which enhances ureogenesis in primary cultured hepatocytes of rats was isolated from a tryptic digest of bovine beta-casein. 2. The structure of the peptide was Ala-Val-Pro-Tyr-Pro-Gln-Arg which is located from 177th to 183rd residues from N-terminal of beta-casein. 3. The peptide also showed the activity to inhibit protein synthesis and protein degradation. 4. It also inhibited DNA synthesis of hepatocytes induced by insulin and/or epidermal growth factor.