A New Synthesis of 2-Methyl-6-methyleneocta-2,7-dien-4-ol,A Component of the Pheromane of California Five-spined Ips

A key intermediate, 2-isocyano-3-hydroxybutyrate (III) was isolated from a reaction of isocyanoacetate (I) with acetaldehyde (II) in the presence of Et₃N. It was found that III was readily converted into 2-isocyanocrotonate (V) and 2-isocyano-2-(1′-hydroxyethyl)-3-hydroxybutyrate (VI) which are undesirable compounds for the synthesis of threonine. However, by use of a metal catalyst (e.g. NiCl₂ or PdCl₂), the isocyano-hydroxy compound (III) was selectively converted into 5-methyl-4-alkoxycarbonyl-2-oxazoline (IV) which is an important precursor of threonine. Furthermore, chemical properties of IV were examined; the results suggested that cis-oxazoline was relatively sensitive to acid, base and heat.

On the basis of these results, the reaction of I with II was carried out using Et₃N-PdCl₂ as a catalyst to obtain threo-threonine (85% purity) in a good yield (85%).     

Column-switching techniques for high-performance liquid chromatography of ibuprofen and mefenamic acid in human serum with short-wavelength ultraviolet detection

Column-switching techniques for high-performance liquid chromatography of two acidic drugs, ibuprofen and mefenamic acid, in human serum with short-wavelength ultraviolet detection are described. The method involved extraction of the analyte from acidified serum followed by the chromatographic analysis using column switching. Three ODS columns were used each with different mobile phase, utilizing the difference of ion-pair formation or of ionization caused by pH change. The method offered high sensitivity and selectivity, with short-wavelength ultraviolet detection at 221 nm for ibuprofen and at 219 nm for mefenamic acid. The detection limits were 0.5 ng/ml (2.4 pmol/ml) for ibuprofen and 0.1 ng/ml (0.4 pmol/ml) for mefenamic acid using 1 ml of serum, both at a signal-to-noise ratio of 3. With some modifications, the principle of the method would be applicable to other acidic compounds in biological fluids.     

Studies on Leaf Surface Lipid of Tobacco III. Compositional Change in Alkane during Growth and Senescence of Tobacco Leaves

Alkane is the major constituent of epicuticular wax universally distributed in plants. Tobacco leaves contained 5–10 mg of alkane per 1000 cm². The content gradually increased with leaf age. Leaves on the upper stalk contained more alkane than those on lower stalk. Components with carbon numbers from 27 to 33 occupied more than 98 % of the total alkane content. In relative ratios of alkane components, anteiso-C₃₀ and normal-C₃₁ were most drastically and increased, respectively, with leaf age regardless of stalk position. On the other hand, normal-C₂₉ and normal-C₃₃ increased and decreased, respectively, from the upper to lower stalk positions without being affected by leaf age. These results suggest the possible use of alkane composition as an index of leaf maturity and stalk position, for example, the ratio of anteiso-C₃₀/normal-C₃₁ for maturity and normal-C₃₃/normal-C₂₉ for stalk position.     

The effect of pyrazines on the metabolism of tryptophan and nicotinamide adenine dinucleotide in the rat Evidence of the formation of a potent inhibitor of aminocarboxy-muconate-semialdehyde decarboxylase from pyrazinamide

The intraperitoneal or oral administration of pyrazinamide and pyrazinoic acid (pyrazine 2-carboxylic acid) resulted in a marked increase of the NAD content in rat liver. The injections of pyrazine and pyrazine 2,3-dicarboxylic acid exhibited no significant effect on the hepatic NAD content. The boiled extract obtained from liver and kidney of rat injected with either pyrazinamide or pyrazinoic acid exhibited a potent inhibitory effect on the aminocarboxymuconate-semialdehyde decarboxylase (EC 4.1.1.45) activity in either liver or kidney, although pyrazinamide or pyrazinoic acid per se did not inhibit the enzyme activity. The unknown inhibitor of aminocarboxymuconate-semialdehyde decarboxylase was dialysable and heat-stable, and mostly excreted in urine by 6 and 12 h after injection of pyrazinoic acid and pyrazinamide, respectively. Pyrazine 2,3-dicarboxylic acid, pyrazine, nicotinamide, nicotinic acid, tryptophan, anthranilic acid, 5-hydroxyanthranilic acid and quinolinic acid exhibited no significant effect on the aminocarboxymuconate-semialdehyde decarboxylase activity in liver and kidney at the concentration of 1 mM in the reaction mixture. The expired ¹⁴CO₂ from l-[benzen ring-U-¹⁴C]tryptophan was markedly decreased by the pyrazinamide injection, while the urinary excretion of ¹⁴C-labeled metabolites from l-tryptophan, mainly quinolinic acid, was markedly increased. These results suggest that the glutarate pathway of l-tryptophan was strongly inhibited by the inhibitor produced after the administration of pyrazinoic acid and pyrazinamide. Pyrazinamide but not pyrazinoic acid also exhibited a significant inhibition of the nuclear enzyme poly(ADP-ribose) synthetase in rat liver.     

Emergence of Polymorphic Mating Strategies in Robot Colonies

Polymorphism has fascinated evolutionary biologists since the time of Darwin. Biologists have observed discrete alternative mating strategies in many different species. In this study, we demonstrate that polymorphic mating strategies can emerge in a colony of hermaphrodite robots. We used a survival and reproduction task where the robots maintained their energy levels by capturing energy sources and physically exchanged genotypes for the reproduction of offspring. The reproductive success was dependent on the individuals'' energy levels, which created a natural trade-off between the time invested in maintaining a high energy level and the time invested in attracting mating partners. We performed experiments in environments with different density of energy sources and observed a variety in the mating behavior when a robot could see both an energy source and a potential mating partner. The individuals could be classified into two phenotypes: 1) forager, who always chooses to capture energy sources, and 2) tracker, who keeps track of potential mating partners if its energy level is above a threshold. In four out of the seven highest fitness populations in different environments, we found subpopulations with distinct differences in genotype and in behavioral phenotype. We analyzed the fitnesses of the foragers and the trackers by sampling them from each subpopulation and mixing with different ratios in a population. The fitness curves for the two subpopulations crossed at about 25% of foragers in the population, showing the evolutionary stability of the polymorphism. In one of those polymorphic populations, the trackers were further split into two subpopulations: (strong trackers) and (weak trackers). Our analyses show that the population consisting of three phenotypes also constituted several stable polymorphic evolutionarily stable states. To our knowledge, our study is the first to demonstrate the emergence of polymorphic evolutionarily stable strategies within a robot evolution framework.     

Peptization of the Gel of Konjac Mannan

The addition of 1,8-pyrenequinone into the assay system containing rat liver homogenates (S-9) caused an approximately 10-fold increase in the mutagenicity of 2-acetylaminofluorene (AAF) in the current Salmonella reversion assay system. Since no chemical reaction between 1,8-pyrenequinone and AAF was observed, the in vitro effects of 1,8-pyrenequinone on the metabolisms of AAF with S-9 mix were studied. The enhancement of mutagenicity by 1,8-pyrenequinone was not dependent on the dose of NADPH under the present assay condition. The mutagenicity of AAF was increased approximately 4-fold by the addition of 1,8-pyrenequinone into microsomes, whereas it remained at the spontaneous level in the presence of cytosol. However, by reconstituting microsomes with cytosol, the mutagenicity enhancing activity was recovered to the original level. Since 1,8-pyrenequinone inhibited the AAF hydroxylase activity, chemical analysis of the incubation mixture of AAF was tried. This indicated that a higher amount of unmetabolized AAF remained and higher amounts of 2-aminofluorene and N-hydroxy-2-acetylaminofluorene were accumulated in the presence of 1,8-pyrenequinone compared with those in the absence of 1,8-pyrenequinone. From these results, it seems probable that 1,8-pyrenequinone inhibits C-hydroxylation (the detoxifying pathway) and promotes N-hydroxylation (the activating pathway) as well as deacetylation in the AAF metabolism.     

Phase transitions of the purple membrane and the brown holo-membrane X-ray diffraction,circular dichroism spectrum and absorption spectrum studies

The phase transition of the purple membrane observed by differential scanning calorimetry (Jackson, M.B. and Sturtevant, J.M. (1978) Biochemistry 17, 911–915) has been investigated by X-ray diffraction, circular dichroism and absorption spectrum, in comparison with the phase transition in the brown holo-membrane. The two-dimensional crystal of bacteriorhodopsin transformed into two-dimensional liquid around 74–78°C in the purple membrane and around 50–60°C in the brown holo-membrane. The X-ray diffraction patterns obtained at 78°C for the purple membrane and at 60°C for the brown holo-membrane exhibit several broad peaks. Analysis of the pattern suggests that bacteriorhodopsin molecules aggregate in trimers even above the phase transition temperature. The negative circular dichroism band in the visible region is still present at 80°C in the purple membrane and at 60°C in the brown holo-membrane, but becomes negligibly small at 70°C in the brown holo-membrane. The 560 nm absorption peak due to bacteriorhodopsin changes its position and height drastically around 80°C in the brown holo-membrane as in the purple membrane. X-ray diffraction studies have been made on membranes of total lipids extracted from the purple membrane. No indication of the phase transition has been found between ?81°C and 77°C.