The intersectional hybrid between Weigela hortensis and W. maximowiczii (Caprifoliaceae)

Morphologically intermediate plants between Weigela hortensis (Siebold & Zucc.) K.Koch and W. maximowiczii (S.Moore) Rehder have been found in Miyagi and Yamagata Pref., northern Japan. Quantitative character analyses of flowers, pollen stainability and molecular analyses indicated that the intermediate plants were hybrids of those two species. This is the first record of an intersectional hybrid with W. maximowiczii (sect. Weigelastrum ) as one of the parent species. The morphological differences among hybrid individuals imply the possibility of backcrosses or formation of second or later generations of hybrids, although those may be quite rare because of a low frequency of viable pollen grains. Causes of hybridization between two distantly-related species in Weigela are discussed. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 369–380.     

Occurrence of 2-Aminobutanoic Acid in the Incubation Medium of Mixed Rumen Ciliate Protozoa1

An unknown, ninhydrin-positive substance detected on paper chromatograms of the endogenous metabolites of mixed rumen ciliate protozoa was isolated and purified by column chromatography with ‘Dowex’ 50-X8 resin and identified as 2-aminobutanoic acid (α-amino-n-butyric acid) on the basis of elementary analysis, mass spectrometry, paper chromatography, infrared spectrometry, and melting point.     

Extensive size homoplasy at a microsatellite locus in the Japanese bumblebee, Bombus diversus

An extensive size homoplasy was found at microsatellite locus B11 of the bumblebee, Bombus diversus, in northern to central Honshu, Japan. A total of 16 alleles of different nucleotide sequences in five length morphs was obtained at B11 for this species. Of these alleles, five were 141 base pairs (bp) in length, five were 137 bp and four were 133 bp. Allele diversity in each length morph was high compared with previous studies. It is noteworthy that this extensive size homoplasy was found in a relatively small geographic area, in contrast to results from previous studies. Reconstruction of a median‐joining network revealed the complicated evolutionary process of the locus, involving insertion/deletion and point mutations. Preliminary estimation of the mutation rate of the B11 locus in B. diversus gives a value comparable to those estimated from experimental Drosophila populations. Effects of the extensive size homoplasy in population genetic studies is discussed.     

Change in CO2 balance under a series of forestry activities in a cool-temperate mixed forest with dense undergrowth

To evaluate the effects on CO₂ exchange of clearcutting a mixed forest and replacing it with a plantation, 4.5 years of continuous eddy covariance measurements of CO₂ fluxes and soil respiration measurements were conducted in a conifer-broadleaf mixed forest in Hokkaido, Japan. The mixed forest was a weak carbon sink (net ecosystem exchange, −44 g C m⁻² yr⁻¹), and it became a large carbon source (569 g C m⁻² yr⁻¹) after clearcutting. However, the large emission in the harvest year rapidly decreased in the following 2 years (495 and 153 g C m⁻² yr⁻¹, respectively) as the gross primary production (GPP) increased, while the total ecosystem respiration (RE) remained relatively stable. The rapid increase in GPP was attributed to an increase in biomass and photosynthetic activity of Sasa dwarf bamboo, an understory species. Soil respiration increased in the 3 years following clearcutting, in the first year mainly owing to the change in the gap ratio of the forest, and in the following years because of increased root respiration by the bamboo. The ratio of soil respiration to RE increased from 44% in the forest to nearly 100% after clearcutting, and aboveground parts of the vegetation contributed little to the RE although the respiration chamber measurements showed heterogeneous soil condition after clearcutting.     

A gibberellin-regulated protein phosphorylated by a putative Ca2+-dependent protein kinase is G-protein mediated in rice root

The GA-signal transduction pathways downstream to the Gα protein in rice seedling root were investigated using in-gel kinase assay and in vitro protein phosphorylation techniques with a Gα protein defective mutant, d1. A 50-kDa protein kinase was detected downstream to Gα protein in the membrane fraction of rice seedling roots using an in-gel kinase assay with histone III-S as a substrate. The activity of a 50-kDa protein kinase increased in the wild-type rice by gibberellin (GA₃) treatment, but did not change in the d1 mutant. This protein kinase activity was inhibited by the Ca²⁺ chelator ethyleneglycol-bis-(beta-aminoethylether)-N,N,N ¹,N ¹-tetraacetic acid (EGTA), protein kinase inhibitors, staurosporine and H7, and calmodulin antagonist, trifluoperazine, suggesting that the 50-kDa protein kinase is a putative plant Ca²⁺-dependent protein kinase (CDPK). The activity of the 50-kDa putative CDPK reached its highest level at 3 h after GA₃ treatment and then gradually declined with time. In order to identify the endogenous substrate for 50-kDa putative CDPK, two-dimensional polyacrylamide gel electrophoresis followed by in vitro protein phosphorylation was carried out. The phosphorylation activity of an endogenous protein PP30, identified as an unknown protein having molecular weight 30 kDa and isoelectric point 5.8 was increased in the wild-type rice by GA₃ treatment, compared with the d1 mutant. The addition of GA₃ treated membrane fraction, which predominantly represent a 50-kDa putative CDPK further increased the phosphorylation of PP30. Almost similar to GA₃ treatment, phosphorylation activity of PP30 was also increased by the treatment with cholera toxin in the wild-type rice but not in d1 mutant. These results suggest that the 50-kDa putative CDPK and an unknown protein, PP30 promoted by GA₃ treatment are G-protein mediated in rice seedling roots.     

Enhanced Melanogenesis Induced by Tyrosinase Gene-Transfer Increases Boron-Uptake and Killing Effect of Boron Neutron Capture Therapy for Amelanotic Melanoma

Specific and powerful cancer killing effect for melanoma by boron neutron capture therapy (BNCT) using DOPA analogue, ¹⁰B-p-boronophenylalanine (¹⁰B-BPA), has been established, but amelanotic melanoma is insufficiently responsive to ¹⁰B-BPA BNCT in comparison with actively melanin-producing melanoma. Although the accumulation mechanism of ¹⁰B-BPA within melanoma was not established, we have recently obtained findings suggesting that melanin monomers, key intermediates for melanin polymer formation, play a critical role in ¹⁰B-BPA accumulation. In addition, there are some kinds of human amelanotic melanomas, such as MEL2A, in which expression of tyrosinase is repressed or lacking though tyrosinase-related protein (TRP)-l and TRP-2 are well expressed. Thus, by using a similarly tyrosinase-lacking mouse amelanotic melanoma cell line, A1059, we constructed TA1059 cells by transfecting human tyrosinase-cDNA into these cells. TA1059 cells acquired higher DOPA-oxidase and DOPAchrome tautomerase activity as well as eumelanin content at even higher levels than those of B16F10 cells. TA1059 cells showed about 2.5 times higher ^p-boronophenylalanine (BPA) uptake than A1059 cells in culture. In animal experiments, by using these cell lines, tumor growth of TA1059 was significantly suppressed by ¹⁰B-BPA BNCT as compared with A1059. These findings indicate that the induction of active melanin biosynthesis by melanogenic gene-transfer effectively improves the treatment of amelanotic melanoma by BNCT.     

Yeast Glucan in the Cyst Wall of Pneumocystis carinii

Ultrastructurally, the cyst wall of Pneumocystis carinii consists of an electron-dense outer layer, an electron-lucent middle layer, and an innermost plasmalemma. This is similar in appearance to the cell wall of some yeasts, e.g. Saccharomyces cerevisiae , which consists of an outer dense layer of mannan, a middle lucent layer of β−1,3-glucan (yeast glucan) and an innermost plasmalemma. The cyst wall P. carinii , as well as the cell wall of S. cerevisiae , can be labeled by a variety of methods which stain polysaccharides, such as Gomori's methenamine silver (GMS) and by Aniline blue, a dye which selectively stains β-1,3-glucan. The treatment of P. carinii cysts with Zymolyase, which the key enzyme is β,3-gIucan laminari-pentaohydrolase, results in lysis of the outer 2 layers of the cyst wall and the loss of positive staining by both GMS and Aniline blue. The lysis of elements of the cyst wall of P. carinii is achieved under the same conditions and concentration at which Zymolyase lyses the outer 2 layers of the cell wall of viable cells of S. cerevisiae . These observations indicate that a major component of the cyst wall of P. carinii is β-1,3-glucan.