Nitrogen budget in the euphotic zone of Lake Biwa from spring to summer, 1986

The production rate of participate nitrogen (PN) in Lake Biwafrom March to June 1986 was calculated by monthly measurementsof the proteinaceous nitrogen production rates. The ‘new’production rate was estimated from the decrease in nitrate inthe euphotic zone; during this period (91 days) it was estimatedas 93 mg atoms m^–2, and accounted for 20% of the ‘total’PN production (460 mg atoms m^–2). This implies that {smalltilde}80% of the PN produced might be recycled in the euphoticzone. The increase in PN in the euphotic zone during this period(27 mg atoms m^–2) accounted for 5.9% of the ‘total’PN production. This indicates that the remaining 14% of PN producedin the euphotic zone was vertically transported. Sediment trapexperiments at 30 m depth indicate that 8.1% of the PN producedin the euphotic zone was measured as downward flux at 30 m depthduring the stagnation period. Decompositional loss of PN between12.5 (bottom of the euphotic zone) and 30 m depth was estimatedas 17 mg atoms m^–2. This was calculated on the basis ofaccumulation of ammonium, which accounted for 3.7% of the ‘total’PN production. The flux from the euphotic zone thus accountedfor 12% of the ‘total’ PN production, suggestingthe validity of the production model.     

Dominant honeybee colony infestation by Varroa destructor (Acari: Varroidae) K haplotype in Japan

Applied Entomology and Zoology - Varroa destructor Anderson and Trueman (Acari: Varroidae) are ectoparasitic mites found in the western honeybee Apis mellifera Linnaeus (Hymenoptera: Apidae)....     

Small GTP-Binding Proteins are Associated with the Vesicles That are Targeted to Vacuoles in Developing Pumpkin Cotyledons

Dense vesicles mediate the final step in the delivery of seedproteins to vacuoles in developing pumpkin (Cucurbita sp.) cotyledons.To explore the vesicle-mediated transport system that is targetedto vacuoles in plant cells, we isolated the dense vesicles andexamined then for the presence of guanine nucleotide-bindingproteins. GTP-binding proteins of 25 kDa and 27 kDa were detectedon the isolated vesicles. The 25-kDa protein had dithiothreitol-dependentGTP-binding activity, but binding of GTP by the 27-kDa proteinshowed no such dependence. Binding of [     

Comparative studies on the reproductive systems ofMazus japonicus andM. miquelii (Scrophulariaceae)

Mazus japonicus is predominantly self-pollinated,M. miquelii mostly cross-pollinated, with a low degree of self-incompatibility. Correlated differences effect structure, development and seismonasty of the stigma, spatial relationships of stigma and anthers, and pollinator visits.M. japonicus produces numerous and light,M. miquelii fewer and heavier seeds. Growth experiments under different temperature regimes demonstrate thatM. japonicus dies after flowering and fruiting, and behaves as an annual, whileM. miquelii has additional asexual propagation and is clearly perennial.M. japonicus grows in somewhat drier and more disturbed habitats thanM. miquelii.     

Origin of chirality: A structural theory

The molecular basis for the origin of chirality is presented: The complex of the anticodon bases and the discriminator base on a D type tRNA can recognize a L type amino acid. Exceptionally the D type tyrosine can be recognizable by the D type tRNA as shown by Calender and Berg. The advantage of such a stereochemical theory over the frozen accident theory is discussed.     

Polypyrimidine/polypurine sequence in plasmid DNA enhances formation of dimer molecules inEscherichia coli

Formation of dimer molecules of a recombinant plasmid, pTIR10, which carries a pyrimidine/purine-biased stretch occurs about 6-fold more efficiently than for the control plasmid pUC19 inEscherichia coli strain JM107. Since pyrimidine/purine-biased sequences have a potential to form unusual DNA structures, this observation suggests that the inserted sequence affects the replication process of plasmid DNA, probably by forming a triple helix under physiological conditions.     

Angiogenesis after administration of basic fibroblast growth factor induces proliferation and differentiation of mesenchymal stem cells in elastic perichondrium in an in vivo model: mini review of three sequential republication-abridged reports

To date, studies on mesenchymal tissue stem cells (MSCs) in the perichondrium have focused on in vitro analysis, and the dynamics of cartilage regeneration from the perichondrium in vivo remain largely unknown. We have attempted to apply cell and tissue engineering methodology for ear reconstruction using cultured chondrocytes. We hypothesized that by inducing angiogenesis with basic fibroblast growth factor (bFGF), MSCs or cartilage precursor cells would proliferate and differentiate into cartilage in vivo and that the regenerated cartilage would maintain its morphology over an extended period. As a result of a single administration of bFGF to the perichondrium, cartilage tissue formed and proliferated while maintaining its morphology for at least 3 months. By day 3 post bFGF treatment, inflammatory cells, primarily comprising mononuclear cells, migrated to the perichondrial region, and the proliferation of matrix metalloproteinase 1 positive cells peaked. During week 1, the perichondrium thickened and proliferation of vascular endothelial cells was noted, along with an increase in the number of CD44-positive and CD90-positive cartilage MSCs/progenitor cells. Neocartilage was formed after 2 weeks, and hypertrophied mature cartilage was formed and maintained after 3 months. Proliferation of the perichondrium and cartilage was bFGF concentration-dependent and was inhibited by neutralizing antibodies. Angiogenesis induction by bFGF was blocked by the administration of an angiogenesis inhibitor, preventing perichondrium proliferation and neocartilage formation. These results suggested that angiogenesis may be important for the induction and differentiation of MSCs/cartilage precursor cells in vivo, and that morphological changes, once occurring, are maintained.     

Degradation of p-Aminoazobenzene byBacillus subtilis

Summary p-Aminoazobenzene (PAAB) was degradated byBacillus subtilis. Both aniline and p-phenylenediamine as degradative compounds from PAAB were identified by thin layer chromatographic-, and high performance liquid chromatographic-methods. This fact suggests that the first degradative reaction of PAAB byB. subtilis is reductive fission of azo bond in PAAB.