Structure-activity relationships among substituted N-benzoyl derivatives of phenylalanine and its analogs in a microbial antitumor prescreen I: Derivatives of o-fluoro-DL-phenylalanine

Twelve derivatives of 0-fluoro-dl-phenylalanine containing fluorine, chlorine, methoxy, and nitro radicals in various positions of the aromatic ring of the benzoyl group were prepared and tested in a Lactobacillus casei system. It was found that most substitutions in the benzoyl phenyl ring resulted in a compound exhibiting greater growth-inhibiting activity than the nonsubstituted benzoyl-o-fluorophenylalanine. The greatest activity was observed in the ortho-substituted fluoro compound and the meta- and para-substituted chloro and nitro compounds. With the methoxy group, the position of substitution appeared unimportant, since all three methoxy isomers exhibited essentially equal inhibition. Nitro substitution in the ortho position had a protective effect in that the product was less active than the unsubstituted benzoyl-o-fluoro-dl-phenylalanine.     

Adaptive Schemes to Recognize an Asynchronously Generated Signal

Decision and estimation algorithms for a signal of asynchronous generation are treated with emphasis on waveform estimation. A simplified model for source statistics is assumed. Starting with a supervised learning model, two algorithms of the non-supervised type are derived. Their estimation error performance is studied by computer simulation.     

Synthesis of eel-calcitonin and (asu1,7)-eel-calcitonin: contribution of the disulfide bond to the hormonal activity

Eel-calcitonin and its [asu1,7]-analog, deamino-dicarba-analog, were synthesized by the conventional solution method. The natural-type product showed 4300 MRC U/mg in the hypocalcemic potency which was comparable to that of the natural hormone isolated from eel. Hormonal activity of the Asu-analog was also as high as 3400 MRC U/mg.     

Biosynthesis of poly-gamma-glutamic acid in plants: transient expression of poly-gamma-glutamate synthetase complex in tobacco leaves

Transient expression of genes coding for the poly-gamma-glutamate (gammaPGA) synthetase system (pgs) was investigated in tobacco plants. Three genes of the pgs, pgsA, pgsB and pgsC, were separately placed under the control of the CaMV 35S promoter and introduced into tobacco leaves via Agrobacterium infection. Synthesized gammaPGA in plant tissues was detected immunologically with mouse anti-gammaPGA antiserum which specifically reacts with gammaPGA on a nitrocellulose membrane. Confirmation of gammaPGA biosynthesis in the transient expression analysis in tobacco tissue indicates that subunits of pgs complex were expressed and reassembled in a functional form.     

Preparation and fractionation of conjugated trienes from α-linolenic acid and their growth-inhibitory effects on human tumor cells and fibroblasts

Conjugated α-linolenic acid (ClnA) was prepared from α-linolenic acid (9,12,15–18∶3n−3, LnA) by alkaline treatment; we fractionated CLnA into three peaks by reversed-phase column-HPLC as evidenced by monitoring absorbance at 205, 235, and 268 nm. Peak I was a conjugated dienoic FA derived from LnA, whereas Peaks II and III were conjugated trienoic LnA. Proton NMR analysis showed that Peak III consisted of the all-trans isomer. The methylated Peak III was further divided into five peaks (Peaks IV–VIII) by silver ion column-HPLC. Peak V, a major constituent in the Peak III fraction, was identified as conjugated 10t,12t,14t-LnA by GC-EIMS and ¹H NMR analysis. Peaks III and V, which consisted of conjugated all-trans trienoic LnA, had stronger growth-inhibitory effects on human tumor cell lines than the other collected peaks and strongly induced lipid peroxidation as compared with Peaks I, II, and LnA. We propose that conjugated all-trans trienoic FA have the strongest growth-inhibitory effect among the conjugated trienoic acids and conjugated dienoic acids produced by alkaline treatment of α-LnA, and that this effect is mediated by lipid peroxidation.     

High-speed digital-signal transmission experiments by optical wavelength-division multiplexing

The letter reports results obtained with laboratory transmission experiments on high-speed digital signals by optical wavelength-division multiplexing, using a newly developed optical multiplexer and demultiplexer, as well as other high-performance optical devices and fibres.     

Leukemia developing after 131I treatment for thyroid cancer in a patient with Werner's syndrome: molecular and cytogenetic studies

A 40-year-old female patient with Werner's syndrome (WS) suffering from thyroid cancer and myelodysplastic syndrome (MDS) is reported. She had been diagnosed as having WS complicated with thyroid cancer seven years previously. Total thyroidectomy and radioactive iodine (131I, 100 mCi/year) therapy for seven years had slowed the progression of thyroid cancer. She suffered a sudden onset of MDS at the age of 40 years. After six months she died from overt leukemia. We found an additional chromosome aberration of chromosome 10 in the progression of leukemia from MDS.     

Dependence of zero-shear viscosity and steady-state compliance on molecular weight between entanglements for ethylene-cycloolefin copolymers

Dynamic viscoelastic properties of a series of cyclic olefin copolymers have been investigated. The specimens differ in total molecular weight as well as molecular weight between entanglements. The angular frequency (ω) dependence curves of dynamic storage and loss moduli (G′ and G″, respectively) of the specimens have shown that G′ ∝ ω² and G″ ∝ ω in the terminal region, and a plateau region at high ω. On the basis of the experimental results, the dependence of total molecular weight as well as molecular weight between entanglements has been examined for zero-shear viscosity (η₀) and steady-state compliance (J_e). It is shown that for the melts of the copolymers in the entangled regime, M_w being the weight-average molecular weight and M_e the molecular weight between entanglements. The steady-state compliance J_e for the melts scales with M_e and M_w as .