A comparison of screening methods for antioxidant activity in seaweeds

The inhibition of lipid peroxidation and radical scavenging effects were studied to evaluate the antioxidant activity for extracts of 17 species of seaweed. The antioxidant effect was evaluated by determination of lipoxygenase activity and by α, α-diphenyl-β-picrylhydrazyl (DPPH) decolorization. Lipoxygenase activity was depressed in the presence of aqueous and ethanol extracts of 4 algal species; Sargassum species had the highest antioxidant activity of all the species examined. The ethanol extracts of one Sargassum species showed competitive inhibition with the substrate. The same species also showed radical scavenging activity in the DPPH decolorization test. Comparison of these results shows no relationship between enzyme inhibition and radical scavenging activity. This revised version was published online in August 2006 with corrections to the Cover Date.     

Coexistence of fast-type and slow-type C-proteins in neonatal chicken breast muscle

Two different C-protein variants which selectively react with either monoclonal anti-fast C-protein antibody (MF-1) or monoclonal anti-slow C-protein antibody (ALD-66) were separated from neonatal chicken pectoralis muscle by hydroxylapatite column chromatography. Myofibrils isolated from the neonatal chicken muscle reacted with both monoclonal antibodies as examined by an indirect immunofluorescence method. These observations strongly indicate that both fast-type and slow-type C-proteins are expressed in the neonatal chicken skeletal muscle. Both of them are intermingled and assembled in the same myofibrils.     

Role of the Photoperiod Preceding a Flower-Inductive Dark Period in Dark-Grown Seedlings of Pharbitis nil Choisy

Flowering responses to a single photoperiod, of various durationsand irradiances, followed by an inductive dark period were investigatedwith dark-grown seedlings of Pharbitis nil Choisy. The numberof flower buds induced in each plant (NFB) increased with theincrease of both duration and irradiance of the photoperiod.Reciprocity did not hold for this photoresponse within the rangeof 0-16 h and 2.5-10 W-m^-2, NFB depending on the duration ratherthan the irradiance. With lengthening of the dark period followinga photoperiod of 8 h or less, two different phases alternatelyappeared so that NFB sharply increased at 20-24 h and 40-43h after the onset of the photoperiod, then gradually decreased.When the photoperiod was longer than 8 h, NFB sharply increasedat 12–16 h after the end of the photoperiod and remainedaround the saturated value with longer dark periods. Far-redlight given immediately after the photoperiod inhibited flowering,the inhibitory effect being stronger the shorter the photoperiod.This far-red effect is mediated by phytochrome and P_FR seemsto be required during the inductive dark period following ashort photoperiod for floral induction. (Received December 23, 1983; Accepted April 12, 1984)     

Phytochrome Control of Its Own Synthesis in Pisum sativum

An analysis of phytochrome synthesis in Pisum seedlings by measuringthe activity of polysomal polyadenylated RNA (poly-A⁺-RNA) codingfor phytochrome apoprotein showed phytochrome control of itsown synthesis; brief red-light irradiation of pea seedlingsinhibited the activity of the RNA, and the red-light effectwas red/far-red reversible. ⁴ Permanent address: Biology Department, Faculty of Science,University of Tokyo, Hongo, Tokyo 113, Japan. (Received August 13, 1984; Accepted September 17, 1984)     

Effects of Calcium and Potassium Ions on Phototaxis in Cryptomonas

Effects on positive phototaxis and the cell motility of 7 cationsin 5mM MOPS (morpholinopropane sulfonic acid) buffer (pH 7.0)containing 0.16 mM NaCl, 0.68 mM KCl, 0.5 mM CaCl₂ and 0.16mM MgCl₂ were studied in the unicellular flagellate Cryptomonaswith a photoelectrical measuring apparatus and photomicrography.When calcium ion was removed from the medium by adding 1 mMEGTA (ethylene glycol-bis-(ß-amino-ethylether)-N,N'-tetraaceticacid), the phototactic response was totally inhibited, but theswimming rate was not much affected. The effect of EGTA waspartially reversed by the addition of 1 mM CaCl₂. When 15mMKCl or RbCl was added to the medium, phototaxis was greatlyinhibited, but there was no significant influence on the swimmingrate. Similar but less inhibitory effects were induced in thepresence of NaCl, LiCl and CsCl. KCl-induced inhibition waspartially removed by the addition of 15 mM CaCl₂ or MgCl₂. (Received June 25, 1982; Accepted September 27, 1982)     

Effects of narrow-beam irradiations with blue and far-red light on the timing of cell division in Adiantum gametophytes

Protonemata of the fern Adiantum capillusveneris L., grown as single-cell filaments under continuous red light, were irradiated with a narrow beam of blue light. Only irradiation of the region containing the nucleus induced cell division. Beams of 30 m in width, which corresponds to the diameter of the nucleus, or wider, were equally effective; beams 10 m wide or less were less effective. The results indicate that the nuclear region is the site of the blue- and near ultraviolet-light-absorbing pigment (P_B-NUV) which mediates the timing effect of cell division. In contrast, the effect of a narrow beam of far-red (FR) light, which delays the onset of the blue-light-induced cell division, was found to be present along the entire length of the protonema cell, including the largely vacuolated basal region of the latter. Polarized FR light having the electrical vector parallel to the protonema axis was less effective than that vibrating in other directions. These observations support the hypothesis that the phytochrome controlling the timing effect is localized in the plasma membrane.     

Construction and characterization of the chimeric enzymes between the Bacillus subtilis cellulase and an alkalophilic Bacillus cellulase

The amino acid sequences of cellulase from Bacillus subtilis (BSC) and that from an alkalophilic Bacillus sp. N-4 (NK1) show significant homology in most parts except for the C-terminal portions. Despite the high homology, the pH activity profiles of the two enzymes are quite different; BSC has its optimum pH at 6-6.5, whereas NK1 is active over a broad pH range from 6 to 10.5. In order to identify the structural features which determine such pH activity profiles, chimeric cellulases between BSC and NK1 were constructed using four restriction sites commonly present within the homologous coding sequences, and were produced in Escherichia coli. The chimeric cellulases showed various chromatographic behaviors, reflecting the origins of their C-terminal regions. The pH activity profiles of the chimeric enzymes in the alkaline range could be classified into either the BSC or NK1 type mainly depending on the origins of the fifth C-terminal regions. In the acidic range, the profile was determined only by the origin of the fourth enzyme region from the N terminus. Comparison of the kinetic parameters between pH 5 and 6 using p-nitrophenyl cellobioside as a substrate indicated that the fourth region is responsible for the pH-dependent change of the kcat value. Only a limited number of amino acids in the fourth region may affect on deprotonation of catalytic residues of the cellulases and modulate the catalytic activity in the acidic pH values.     

Molecular cloning, sequencing, and expression of cDNA for rat liver microsomal aldehyde dehydrogenase.

The cDNA clone for rat liver microsomal aldehyde dehydrogenase (msALDH) was isolated and sequenced. The deduced amino acid sequence consisting of 484 amino acid residues revealed that the carboxyl-terminal region of msALDH has a hydrophobic segment, which is probably important for the insertion of this enzyme into the endoplasmic reticulum membrane. COS-1 cells transfected with the expression vector pcD containing the full-length cDNA showed that the active enzyme was expressed and localized mainly on the cytoplasmic surface of the endoplasmic reticulum membranes. It has been proposed that ALDH isozymes form a superfamily consisting of class 1, 2, and 3 ALDHs (Hempel, J., Harper, K., and Lindahl, R., (1989) Biochemistry 28, 1160-1167). Comparison of the amino acid sequence of rat liver msALDH with those of rat other class ALDHs showed that msALDH was 24.2, 24.0, and 65.5% identical to phenobarbital-inducible ALDH (variant class 1), mitochondrial ALDH (class 2), and tumor-associated ALDH (class 3), respectively. Several amino acid residues common to the other known ALDHs, however, were found to be conserved in msALDH. Based on these results, we proposed to classify msALDH as a new type, class 4 ALDH.     

Effects of TAP-144-SR, a sustained-release formulation of a potent GnRH agonist, on experimental endometriosis in the rat

A new, simple experimental endometriosis model was established by auto-transplanting endometrial tissue fragments beneath kidney capsules in female rats. The transplanted endometrial tissue grew well, forming a fluid-filled cyst, which reached maximal size 2 to 3 weeks after transplantation. The growth and maintenance of the transplants was dependent on the ovary: ovariectomy induced regression of well grown transplants. The therapeutic effects of TAP-144-SR (biodegradable microcapsules of copoly (DL-lactic/glycolic acid) copolymer containing a potent GnRH agonist, TAP-144 (D-Leu6-[des-Gly10-NH2]-GnRH ethylamide, leuprolide acetate) were studied with this rat endometriosis model. A single sc injection of TAP-144-SR (corresponding to 1, 10 or 100 micrograms/kg/day of TAP-144), suppressed the growth of the transplanted endometrial tissues and uterine weight in a dose-dependent manner. At 100 micrograms/kg/day, the suppressive effect was more marked in rats given TAP-144-SR than in those given TAP-144 solution. The extent of suppression was comparable to that caused by ovariectomy. Serum and pituitary concentrations of LH and FSH were also reduced more markedly by the administration of TAP-144-SR than by TAP-144 solution. From these results, the present endometriosis model was found to be useful for the evaluation of compounds with potential therapeutic activity. The sustained-release formulation of TAP-144 seems to be beneficial over its solution in terms of both convenience and efficiency for therapy of patients with endometriosis.