Possible roles of calcium and ammonium in the development of bitter pit in apple

Apple trees ( Malus pumila Mill . var. domestica Fuji/ Malus prunifolia rootstock) showed a high susceptibility to bitter pit when supplyed with ammonium salt instead of nitrate (control) in the nutrient solution. When apple fruit was affected by bitter pit, a lower calcium as well as a higher nitrogen and ammonium-nitrogen contents was observed in the fruit flesh near the calyx end. The activity of the mitochondrial Ca²⁺-uptake of the fruit flesh near the calyx end was higher when the tree was grown with ammonium salt than when grown with nitrate. Both the activities of succinate: cytochrome c oxidoreductase and the mitochondrial Ca²⁺-uptake per g of tissue were higher in affected fruit than in healthy fruit. Each of chlorpromazine, N-(6-aminohexyl)-5-chloro-l-napthalenesulfonamide (W-7) and N-(6-aminohexyl)-l-naphthalenesulfonamide (W-5), calmodulin antagonists, was infiltrated into the fruit for 20 min under reduced pressure (about 1 × 10⁴ Pa). Few days later, numerous bitter pit-like spots were observed in both fruit treated with W-7 and chlorpromazine, while only a few spots were observed after the infiltration with W-5, a less potent calmodulin antagonist. A possible mechanism for the occurrence of bitter pit is discussed.     

Synthesis of four diastereoisomers at carbons 24 and 25 of 3 alpha,7 alpha,12 alpha,24-tetrahydroxy-5 beta-cholestan-26-oic acid, intermediates of bile acid biosynthesis

The synthesis of four stereoisomers at C-24 and C-25 of 3 alpha,7 alpha,12 alpha,24-tetrahydroxy-5 beta-cholestan-26-oic acid is described. Pyridium chlorochromate oxidation of 3 alpha,7 alpha,12 alpha-triacetoxy-5 beta-cholan-24-ol (II) prepared from cholic acid (I) afforded 3 alpha,7 alpha,12 alpha-triacetoxy-5 beta-cholan-24-al (III) which was converted to a mixture of the four stereoisomers (IV-VII) by a Reformatsky reaction with ethyl DL-alpha-bromopropionate followed by alkaline hydrolysis. Separation of these isomers (IV-VII) was achieved by silica gel column chromatography, and subsequent reversed-phase partition column chromatography. The configurations at C-24 were elucidated by conversion of each isomer into (24R)- or (24S)-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24-tetrol (XII or XI) by Kolbe electric coupling, the C-24 configurations of which were determined by modified Horeau's method and 13C-nuclear magnetic resonance spectroscopy. The stereochemistries at C-25 were deduced by comparison of IV-VII with the products of the hydroboration followed by oxidation with alkaline hydrogen peroxide of (24E)-3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholest-24-en-26-oic acid (XIII).     

Differential Reduction of Tellurite by Growing Colonies of Normal Yeast and Respiration-Deficient Mutants.

Nagai, Susumu (National Women's University, Nara, Japan). Differential reduction of tellurite by growing colonies of normal yeast and respiration-deficient mutants. J. Bacteriol. 90:220-222. 1965.-A differential reduction of sodium tellurite was observed between normal and respiration-deficient mutant colonies of several species of Saccharomyces. Normal colonies turned black in contrast to mutant colonies which remained nearly white when grown on an agar medium containing 30 to 40 mg per liter of tellurite. Schopfer's medium enriched with yeast extract and a mixture of vitamins was most suitable to develop such black-and-white contrast. The difference was far less obvious when the asparagine of this medium was replaced by other nitrogen sources such as glutamate, peptone, or Casamino Acids. Addition of ammonium sulfate to the medium weakened and sometimes completely reversed the contrast. The usefulness of tellurite medium for diagnostic color differentiation of respiration deficiency was considered.     

Survival of cultured cells and somatic embryos of Asparagus officinalis cryopreserved by vitrification

Cultured cells and somatic embryos derived from the mesophyll tissue of asparagus (Asparagus officinalis L.) were cryopreserved by vitrification. The vitrification solution (PVS) contains (w/v) 22% glycerol, 15% ethylene glycol, 15% propylene glycol and 7% DMSO in Murashige-Skoog medium enriched with 0.5M sorbitol. After initial cryoprotection with sorbitol supplemented MS medium containing 12% ethylene glycol, cells or embryos were exposed stepwise to 85% PVS at 0°C. They were loaded into 0.5 ml transparent straws, and were then plunged directly into liquid nitrogen. After rapid warming, PVS was removed and diluted stepwise. The highest survivals of vitrified cells and embryos were about 65 and 50%, respectively. Surviving embryos developed into plantlets.Abbreviations DMSO dimetyl sulfoxide - PVS vitrification solution - LN liquid nitrogen - DSC differential scanning calorimeter - MS Murashige-Skoog salt medium - NAA naphthalene acetic acid - BA 6-benzyladenine