Deoxynucleoside triphosphate pool of mouse FM3A cell lines unaffected by mutagen treatment

The size of deoxynucleoside triphosphate pool in cultured mouse FM3A cells and mutator mutants isolated from this cell line was determined by high-pressure liquid chromatography after treatment of the cells with ultraviolet light, N-methyl-N′-nitro-N-nitrosoguanidine or mitomycin C. The results showed that, in all the FM3A cell clones, no large increase in the dATP or TTP pool was induced after treatment, while in some cases 40–50% decrease in dCTP pool was observed. It is concluded that the induction of large increase in dNTP pool is not the general effect of the mutagens.     

IgE-mediated 14C-serotonin release from rat mast cells modulated by morphine and endorphins

The formaldehyde method was used to examine the interaction of PGE₁ with morphine, β-endorphin and Met-enkephalin on rat mast cells by their effects on IgE-mediated ¹⁴C-serotonin release. PGE₁ (2×10^?8?2×10^?5 M) caused a dose-related inhibition of the mediator release 1 min after an antigen challenge, and morphine (3×10^?7?3×10^?5 M) reversed this PGE₁ effect dose-dependently and stereospecifically; naloxone (2×10^?4 M) antagonized this action of morphine. β-Endorphin (3×10^?7?10^?5 M) and Met-enkephalin (3×10^?6?10^?4 M) mimicked this morphine action dose-dependently and were antagonized by naloxone (2×10^?4 M). These results suggest that morphine and endorphins modulate immunological mediator release from rat mast cells through opioid receptors.     

Absorption of Copper by Lemna as Influenced by Some Factors Which Nullify the Copper Effect on Flowering and Growth

The effect of copper on flowering and growth of Lemna paucicostata6746 and Lemna gibba G3 in a copper-containing medium is nullifiedby the addition of EDTA, ammonium ions or salicylic acid tothe medium or a decrease in its nitrate concentration. Thesefactors were examined for their effects on the absorption ofcopper by the plants. The addition of EDTA to the medium completelyinhibited the absorption of copper in both species, thus eliminatingthe copper effect. Ammonium ions also inhibited copper absorption,their effectiveness rising with their concentration. Loweringthe nitrate concentration in the medium nullified the coppereffect on flowering in L. paucicostata 6746, and the additionof salicylic acid to the medium also nullified the copper effectin L. gibba G3, both without affecting the absorption of copper. (Received June 7, 1982; Accepted August 27, 1982)     

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; )     

Synthetic ColE1 plasmids carrying genes for penicillin-binding proteins in Escherichia coli

Clarke and Carbon's collection of 2000 Escherichia coli strains which harbor ColE1 plasmids carrying small random segments of the E. coli chromosome was screened for the correction of mutational defects in penicillin-binding proteins (PBPs): ponA (PBP-1a), ponB (PBP-1b), dacB (PBP-4), and pfv (PBP-5). We found plasmids carrying chromosomal segments containing ponA⁺-aroB⁺ (pLC29-47), ponB⁺-tonA⁺ (pLC4-43, pLC4-44, and pLC19-19), and argG⁺-dacB⁺ (pLC10-46 and pLC18-38). Characters of these plasmids were analyzed. Two other plasmids (pLC26-6 and pLC4-14) previously found to correct ftsI mutation (Y. Nishimura, Y. Takeda, A. Nishimura, H. Suzuki, M. Inouye, and Y. Hirota (1977)Plasmid1, 67–77) were also investigated further. Restriction maps of chromosomal DNAs carried by pLC29-47, pLC4-44, pLC19-19, pLC18-38, pLC26-6, and pLC4-14 were constructed. The regions of ponB-tonA on pLC4-44 and pLC19-19, and of leuA-ftsI-murE and F on pLC26-6 were located on the restriction maps. Although both pLC26-6 and pLC4-14 corrected a thermosensitive mutation, ftsI, which causes a defect in cell division due to abnormal PBP-3, only pLC26-6 led to restoration of PBP-3 production by an ftsI mutant, while pLC4-14 did not. Restriction and heteroduplex analyses of pLC26-6 and pLC4-14 have shown the absence of nucleotide sequence homology between them. The plasmids, pLC29-47 carrying ponA⁺ and pLC4-43, pLC4-44, and pLC19-19 carrying ponB⁺ led the host cell to overproduce the respective PBP.     

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.     

Intranuclear synthesized and native glycogen particles in human gastric cancer: Ultrastructure and histochemistry

Summary Ultrastructural and histochemical studies on human gastric cancer cells disclosed the presence of native and synthesized glycogen particles. The glycogen particles were investigated in the histochemical synthesis of glycogen particles from glucose 1-phosphate by the phosphorylase-branching glycosyltransferase system and non-incubated native glycogen in human gastric adenocarcinoma tubulare.It was observed that focal synthesis localized in the intracytoplasmic matrix and intranucleus. Intranuclear synthesized glycogen appeared as a rosette form ranging from 1100 to 1300 Å in diameter and free particles ranging from 325 to 900 Å in diameter. The synthesis of glycogen appeared in the nucleus as well as in the cytoplasm of the human gastric cancer cells, and the synthesized glycogen was observed as a group of particles. Newly formed glycogen particles appeared occasionally in the interchromatin area as a large macromolecular structure of rosette form.Native glycogen appeared as a free-particle (250–333 Å, medium=300 Å) and aggregated rosette from (694–1050 Å, medium=917 Å) in the autophagosome of gastric cancer cells. There was not, however, a native glycogen particle in the nuclei of gastric cancer cells.Under certain conditions the nuclei of gastric cancer cells can acquire the capacity to synthesize glycogen.     

Sesquiterpenes from Porella species

The Porella liverworts contain abundant sesquiterpenes. ent-Biocyclogermacrene, three ent-aromadendrenes, a unique hydrocarbon, α-pinguisene and two drimane type sesquiterpenes were obtained together with the intensly pungent component, tadeonal, from P. vernicosa and P. gracillima. P. macroloba contained the same sesquiterpenes except for the absence of ent-bicyclogermacrene and the ent-aromadendrenes. The fragrant odor of P. perrottetiana was composed of α-pinene and camphor.     

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.     

Histidine-containing cyclic dipeptides as catalysts in the hydrolysis of carbonic acid p-nitrophenyl esters

A histidine-containing cyclic dipeptide, cyclo(D -Leu-L -His), was almost 20 times as efficient a catalyst as imidazole in the hydrolysis of p-nitrophenyl laurate. The effect of dioxane on the hydrolysis showed that hydrophobic interaction between the cyclic dipeptide and the ester is very important. This reaction obeyed the Michaelis-Menten kinetics, and the Michaelis constant K_m was as low as 9.98 × 10^?5M. Since the linear dipeptide having D -Leu-L -His sequence was nearly inactive in the hydrolysis, the functional groups of cyclo(D -Leu-L -His) in a specific arrangement held by the rigid backbone must have cooperated in the fast hydrolysis. Very weak catalysis by the diasteremeric cyclic dipeptide, cyclo(L -Leu-L -His), in the hydrolysis supported the above view.