Actin Dynamics Affect Mitochondrial Quality Control and Aging in Budding Yeast

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Structure–activity studies on the side chain of a simplified analog of aplysiatoxin (aplog-1) with anti-proliferative activity

We have recently developed a simplified analog of aplysiatoxin (aplog-1) as an activator of protein kinase C (PKC) with anti-proliferative activity like bryostain 1. To identify sites in aplog-1 that could be readily modified to optimize therapeutic performance and to develop a molecular probe for examining the analog’s mode of action, substituent effects on the phenol ring were systematically examined. Whereas hydrophilic acetamido derivatives were less active than aplog-1 in inhibiting cancer cell growth and binding to PKCδ, introduction of hydrophobic bromine and iodine atoms enhanced both biological activities. The anti-proliferative activity was found to correlate closely with molecular hydrophobicity, and maximal activity was observed at a log P value of 4.0–4.5. On the other hand, an induction test with Epstein–Barr virus early antigen demonstrated that these derivatives have less tumor-promoting activity in vitro than aplog-1 regardless of the hydrophobicity of their substituents. These results would facilitate rapid preparation of molecular probes to examine the mechanism of the unique biological activities of aplog-1.     

Separation and Purification of Molecular Species of Galactolipids by High Performance Liquid Chromatography

The NaCl concentration of the growth medium affected hydrogen production by Lyngbya sp. (No. 108) strain. Cells grown in medium containing 3% NaCl produced the most hydrogen. The carbohydrate content of this strain also increased with increasing NaCl concentration of the growth medium up to 720 fig/mg cells at 5 % NaCl. In the presence of 20 finlol/ml MFA (monofluoroacetic acid), inhibition of hydrogen production was observed. We extracted the glycogen from this nonheterocystous filamentous cyanobacterium, Lyngbya sp. (No. 108), and observed that glycogen and carbohydrate consumption of this strain is coincident with hydrogen production.

These results led us to the conclusion that the reserve glycogen or other carbohydrate were used as sources of electron donors for hydrogen production, and that the NaCl concentration of the medium affected the hydrogen production by this strain.     

Studies on Nicotinoids1) as an Insecticide

Toxicities of some nicotinoids as an insecticide were determined. 5′-methylnornicotine, a new synthetic isomer of nicotine, shows similar toxicity to nicotine. The essential moiety in nicotinoids molecule responsible for high toxicity may be 3-pyridylmethylamine group, the amino nitrogen of which must have high basicity (p^K_a′: 7.4~9.0). All nicotinoids of high toxicity are estimated to be largely as monocation at physiological pH of 7.     

Monohydroperoxides Formed by Autoxidation and Photosensitized Oxidation of Methyl Eicosapentaenoate

Methyl eicosapentaenoate (methyl 5,8,11,14,17-eicosapentaenoate) was subjected to autoxidation and methylene blue sensitized photooxidation. Methyl eicosapentaenoate monohydroperoxides, the primary products of the autoxidation and photosensitized oxidation, were isolated by silica gel column chromatography, and characterized by ultraviolet, infrared and nuclear magnetic resonance spectra. The isomeric composition of the monohydroperoxides were determined by gas chromatography-mass spectrometry as follows: the 5-, 8-, 9-, 11-, 12-, 14-, 15- and 18-isomers (autoxidation), and the 5-, 6-, 8-, 9-, 11-, 12-, 14-, 15-, 17- and 18-isomers (photosensitized oxidation). Methyl eicosapentaenoate was readily oxidized both by autoxidation and by photosensitized oxidation.     

Purification and Some Properties of α-Galactosidase from Tubers of Stachys affinis

An α-galactosidase from tubers of S. affinis was purified about 130 fold by ammonium sulfate fractionation, chromatography on DEAE-cellulose and gel filtration on Sephadex G-75. The purified enzyme showed a single protein band on disc gel electrophoresis. The molecular weight of the enzyme was determined to be approximately 42,000 by gel filtration and 44,000 by SDS disc gel electrophoresis. The optimum reaction pH was 5.2. The enzyme hydrolyzed raffinose more rapidly than planteose. The activation energy of raffinose and planteose by the enzyme was estimated to be 7.89 and 11.4 kcal/mol, respectively. The enzyme activity was inhibited by various galactosides and structural analogs of d-galactose. Besides hydrolytic activity, the enzyme also catalyzed the transfer reaction of d-galactosyl residue from raffinose to methanol.     

A Simplified Colorimetry without Incineration of Phosphorus in Phosphatides

An NAD linked formate dehydrogenating enzyme which catalyzed the last step of methanol oxidation system was extracted from the methanol-grown Kloeckera sp. No. 2201. The specific activity of the enzyme in the extract of methanol-grown cells was found to be considerably higher than that of the glucose-grown cells. The enzyme was purified about 35-fold from the extract of methanol-grown cells by heat treatment, column chromatographies on DEAE-cellulose and on hydroxylapatite, and Sephadex G-200 gel filtration. The purified enzyme was shown to be homogeneous by analyses with electrophoresis and ultracentrifuga-tion. The purified enzyme was a kind of NAD: formate oxidoreductase (EC, 1.2.1.2) which catalyzed specifically the oxidation of formate to carbon dioxide. The Km values were 22 mm for formate and 0.1 mm for NAD. The enzyme was inactivated by potassium cyanide, sodium azide, and p-chloromercuribenzoate but not by any metal-chelating reagents tested. Other general properties of the enzyme were also investigated.