Synthesis and properties of lunularic acid

Lunularic acid, a natural plant growth inhibitor, has been synthesized. A high concentration (10–30 ppm) effectively inhibited the elongation of root coleoptiles caused by 0·3 and 0·03 ppm indole-3-acetic acid.     

Effect of the pea embryo on formation and degeneration of the mitochondrial membrane in cotyledons during germination

The effect of removal of the embryo on the properties of mitochondriain pea cotyledons was investigated. During imbibition of theseeds, mitochondrial activity was enhanced in the cotyledons.In later stages of germination, respiratory activity of themitochondria decreased gradually, and no response of the mitochondriato exogenous ADP was observed. Moreover, considerable activityof cytochrome oxidase wasrecovered in the post-mitochondrialfraction. Mitochondrial fractions isolated from senescent cotyledonscontained only fragmented particles of mitochondria. On theother hand, in cotyledons excised from the seeds and cultivatedunder wet condition, the initial development of mitochondriademonstrated in the attached cotyledons was suppressed. However,respiratory activity of the mitochondria increased in the laterstages of cultivation. The mitochondria remained unfragmentedand responded to exogenous ADP during all stages of cultivation.Also, a change in the density of mitochondria which occurredin the germinating attached cotyledons was delayed in the cultivatedexcised cotyledons. (Received February 27, 1973; )     

Stepwise synthesis of oligopeptides with N-carboxy α-amino acid anhydrides. II. Oligopeptides with some polar side chains

The reaction of NCA's with some amino acids having a nucleophilic functional group on the side chain was studied in a heterogeneous reaction medium (acetonitrile-water). Glutamic acid and aspartic acid, having a free carboxyl group on the side chain, were successfully used to synthesize oligopeptides without interactions of the γ- and β-carboxyl group with NCA's. Two products were obtained by the reaction of NCA with L -lysine, which contains a free amino group on the side chain. ε-Protected lysine was used to prepare α-peptides as a nucleophile in the reaction. No racemization was observed in the synthesis of peptides by the NCA method in the heterogeneous solvent system. Oligopeptides with some polar side chains were synthesized by the NCA method.     

Degradation of thyroxine by the microsomal particles from rat liver: I. Correlation between thyroxine degradation and lipid peroxides

1.

1. Particles which catalyze the degradation of l-thyroxine labeled with ¹³¹I at the 3′ and 5′ positions in the β-ring have been isolated from rat liver microsomes and purified.     

A blood-borne factor stimulating hepatic biosynthetic process in hepatectomized rabbits

By measurement of energy charge (ATP+1/2ADP / ATP+ADP+AMP) and mitochondrial phosphorylative activity in liver tissue, it was possible to estimate the states of ATP generation and ATP utilization of normal and regenerative liver. In the liver of partially hepatectomized rabbits, a characteristic decrease in energy charge and increase in mitochondrial phosphorylative activity as compared with those of normal liver were noted, consistent with the notion that ATP-consuming reactions such as protein and nucleic acid syntheses are enhanced in the regenerative process. When normal or hepatectomized rabbits were singly circulated extracorporeally, the mitochondrial phosphorylative activity increased with a concomitant rise in energy charge. In cross-circulation between normal and hepatectomized rabbits, the energy charge of the normal partner decreased markedly with a concomitant elevation in mitochondrial phosphorylative activity, while those in the remnant liver of the hepatectomized partners were not significantly different from those of singly circulated hepatectomized rabbits. The decreased energy charge levels of the normal partner were prevented by the premedication of insulin without a significant effect to the hepatectomized partner. It is suggested that there is a humoral factor stimulating the hepatic energy-requiring biosynthetic process in the blood of hepatectomized rabbits.     

Auxin-induced extension of the isolated epidermis of light-grown pea epicotyls

1. The effect of IAA and FC on the extension of isolated epidermisof light-grown Alaska pea epicotyls was studied under differentconditions with an extension apparatus. The following resultswere obtained.
2. The epidermis extended in response to low pHbuffer solutionof 1–10 mM, maximum extension being achievedat pH below5.5.
3. IAA, 5 mg/liter, caused, although not consistently,an extensionof epidermal strips in 1 mM buffer, but not at10 mM.
4. Consistent extension of the isolated epidermis dueto IAA wasobtained by addition of GTP, ATP, ITP or UTP (sodiumsalts),but not nucleosides, nitrogen bases or sugars.
5. A fungaltoxin, FC, at 10^–5 M induced extension of theepidermiswithout addition of the nucleoside triphosphates.
6. IAA andFC caused H⁺ extrusion in peeled epicotyl segments bothin thepresence and absence of GTP. IAA caused appreciable H⁺extrusionin the isolated epidermis only in the presence ofGTP, whereasH⁺ extrusion by the epidermis was induced by FCeven in theabsence of GTP.

From these results, we concluded that IAA induces extensionof the isolated epidermis under the above conditions throughthe mediation of H⁺ ions. (Received July 12, 1976; )     

Distribution pattern of anthocyanidins and anthocyanins in polygonaceous plants

Forty-six polygonaceous plants were examined regarding the nature and amount of anthocyanidins which were obtained as the HCl-hydrolyzate of leaf proanthocyanidins. All of the plants examined contained cyanidin in common in their hydrolyzed leafextracts. From this survey, at least three groups of plants may be distinguished; the first containing only cyanidin, the second delphinidin in addition to cyanidin and the third an unknown anthocyanidin (called PA-X) and cyanidin. Of the plants examined,Polygonum cuspidatum leaves yielded cyanidin in the largest amounf. There were no geographical and seasondl variations of the distribution pattern of pigments in the plants, and also no variation of anthocyanidin-types was observed in young and mature leaves. A further survey of anthocyanins in the plants revealed that delphinidin glycosides are present in the sepals ofPolygonum nepalense andP. thunbergii.     

Androgen metabolism in sheep

³H-Testosterone (³H-T) plus ¹⁴C-androst-4-ene-3.17-dione (A-dione) and ³H-epi-testosterone (17α-hydroxy-4-androsten-3-one) (epiT) plus ¹⁴C-T were injected intravenously into two male sheep with bile fistulae, respectively. Urine and bile samples were collected at intervals for 4–8 hours and analyzed by the use of DEAE-Sephadex A-25 and Lipidex 5000 columns, TLC, and paper chromatography; the aglycones were identified by co-crystallization with authentic standards.Five fractions were obtained from urine and bile: unconjugated, glucosiduronates, sulfates, sulfo-glucosiduronates and disulfates. In urine, the major conjugates were glucosiduronates, while sulfates predominated in bile. About 80–90% of recovered radioactivity was found to be either glucosiduronates or sulfates. Among the metabolites identified, epi-T was the principal one, accounting for 10–15% of the administered doses. Conversion to 17α-hydroxysteroids thus appears to be a major route of metabolism of the androgens administered in sheep. Other metabolites in the glucosiduronate and sulfate fractions were androsterone, etiocholanolone (3α-hydroxy-5β-androstan-17-one), 5β-androstane-3α, 17β-diol, two unknown diols and polar metabolites. The results indicated that androgen metabolism is somewhat unusual in sheep, as compared with other animals and the human.     

A Study of stepwise conformational changes in poly(β-benzyl-L-aspartate) with the helix–coil transition by means of proton and carbon-13 NMR

The helix–coil transition for poly(β-benzyl-L -aspartate) [poly(Asp[OBzl])] in solvent mixtures of trifluoroacetic acid/deuterated chloroform (F₃AcOH/CDCl₃) was studied by means of proton and carbon-13 nmr. Conformational fixation of the side chain occurs before the coil–helix transition of the backbone, when neighboring phenyl rings face each other. Another type of conformational fixation occurs in the side chain after the coil–helix transition of the backbone. These conformational changes of the side chain are due to the changes of the strength of the interaction between the side-chain ester group and the F₃AcOH molecule. In the absence of F₃AcOH (coil-forming solvent), the polymer has a rather rigid structure in which the side chain may wrap around the backbone. These conformational changes of the polymer are closely related to the changes of the interaction between the polymer and F₃AcOH molecules.     

Lens differentiation in cultures of neural retinal cells of human fetuses

Neural retinal cells of human fetuses at approximately 9 and 15 weeks after conception were cultured in vitro. In early stages of culturing (up to about 10 days), a number of neuronal cells with axon-like processes were formed. Within about 20 days, many neuronal cells started to degenerate, while a number of “lentoid bodies” were identified by immunoelectrophoresis and immunofluorescent techniques using anti-rat lens serum which cross-reacted with human crystallins. Ultrastructural observations also revealed that cells of “lentoid bodies” represent typical profiles of lens fibers.