Plasminogen with type-I mutation is polymorphic in the Japanese population

Summary A functionally inactive plasminogen (PLG) variant designated as PLG M5 is polymorphic in the Japanese population and has a feature common to PLG with type-I mutation that has a codon 601 missense mutation in exon 15 (GCT for AlaACT for Thr). This study was conducted to clarify whether the type-I mutation of PLG is present in PLG M5 and polymorphic in the Japanese population. Direct sequencing of the amplified DNA from the PLG gene in a heterozygote for PLG M5 revealed that the sequence of the exon 15 in the gene for PLG M5 is identical with that in the PLG gene with type-I mutation. In addition, the amplified DNA from the PLG gene in 12 heterozyotes for PLG M5 reacted with the probe for the type-I mutation in dot blot hybridization with an allele-specific oligonucleotide probe. The heterozygote for PLG with type-I mutation was found in 2.2% of 360 unrelated healthy subjects. These data indicate that the type-I mutation of PLG is present in PLG M5 and polymorphic in the Japanese population. The data also suggest that the PLG M5 is identical with PLG Tochigi and Kagoshima.     

Metabolism of 3,4-Dimethylphenyl N-Methylcarbamate in White Rats

Orally administered 3,4-dimethylphenyl N-methylcarbamate labelled with carbon-14 at 4-CH₃ was easily absorbed from the gastrointestinal tract of male Wistar rats and distributed into the tissues. Elimination of the radioactivity was rapid and essentially complete; namely during 48 hr approximately 92% and 5% of the total radioactivity were excreted respectively into urine and feces. The content of the intact carbamate compound in the urine was less than 0.5%. Major degradation products were identified as 3-methyl-4-carboxyphenyl N-methylcarbamate, its N-hydroxymethyl analog and its component phenol. Much less amount of direct hydrolysis product of the original carbamate, 3,4-dimethylphenol and its conjugated forms was demonstrated. 3,4-Dimethylphenyl N-methylcarbamate is presumed to undergo biodegradation through oxidative pathways.     

DNA packaging proteins Glom and Glom2 coordinately organize the mitochondrial nucleoid of Physarum polycephalum

Mitochondrial DNA (mtDNA) is generally packaged into the mitochondrial nucleoid (mt-nucleoid) by a high-mobility group (HMG) protein. Glom is an mtDNA-packaging HMG protein in Physarum polycephalum. Here we identified a new mtDNA-packaging protein, Glom2, which had a region homologous with yeast Mgm101. Glom2 could bind to an entire mtDNA and worked synergistically with Glom for condensation of mtDNA in vitro. Down-regulation of Glom2 enhanced the alteration of mt-nucleoid morphology and the loss of mtDNA induced by down-regulation of Glom, and impaired mRNA accumulation of some mtDNA-encoded genes. These data suggest that Glom2 may organize the mt-nucleoid coordinately with Glom.     

Amensalism via webs causes unidirectional shifts of dominance in spider mite communities

Competitive displacement is considered the most severe consequence of interspecific competition; if a superior competitor invades the habitat of an inferior species, the inferior species will be displaced. Most displacements previously reported among arthropods were caused by exotic species. The lack of investigation of displacement among native species may be due to their apparently harmonious coexistence, even if it is equivalent to an outcome of interspecific association. A seasonal change in the species composition of spider mites, from Panonychus ulmi to Tetranychus urticae, is observed in apple trees worldwide. Previous laboratory experiments have revealed amensal effects of T. urticae on P. ulmi via their webs. Using manipulation experiments in an orchard, we tested whether this seasonal change in species composition occurred as the result of interspecific competition between these spider mites. Invasion by T. urticae prevented an increase in P. ulmi densities throughout the experimental periods. Degree of overlap relative to the independent distribution on a leaf-surface basis (ω _S) changed from positive to negative with increasing density of T. urticae. T. urticae invasion drove P. ulmi toward upper leaf surfaces (competitor-free space). The niche adjustment by P. ulmi occurred between leaf surfaces but not among leaves. Our findings show that asymmetrical competition between T. urticae and P. ulmi plays an important role in this unidirectional displacement and that the existence of refuges within a leaf produces the apparently harmonious coexistence of the mites and obscures their negative association.     

A new class of pentapeptide KISS1 receptor agonists with hypothalamic–pituitary–gonadal axis activation

The kisspeptin (Kp, Kp-54, metastin)/KISS1R system plays crucial roles in regulating the secretion of gonadotropin-releasing hormone. Continuous administration of nonapeptide Kp analogs caused plasma testosterone depletion, whereas bolus administration caused strong plasma testosterone elevation in male rats. To develop a new class of small peptide drugs, we focused on stepwise N-terminal truncation of Kp analogs and discovered potent pentapeptide analogs. Benzoyl-Phe-azaGly-Leu-Arg(Me)-Trp-NH₂ (16) exhibited high agonist activity for KISS1R and excellent metabolic stability in rat serum. A single injection of a 4-pyridyl analog (19) at the N-terminus of 16 into male Sprague Dawley rats caused a robust increase in plasma luteinizing hormone levels, but unlike continuous administration of nonapeptide Kp analogs, continuous administration of 19 maintained moderate testosterone levels in rats. These results indicated that small peptide drugs can be successfully developed for treating sex hormone deficiency.     

Spatial distribution of mDLG6 mRNA in embryonic and adult mouse brain

We have isolated mouse DLG6 (mDLG6) cDNA clones by RT-PCR and then by using the RT-PCR products to screen a mouse brain cDNA library. The deduced amino acid sequence of mDLG6 shows 79.2% and 82.7% overall identity to human (hDLG6) and rat DLG6 (rDLG6), respectively. In situ hybridization revealed that mDLG6 mRNA is predominantly expressed in embryonic and adult brain.     

Uptake of AMP, ADP, and ATP in Escherichia coli W

The uptake activity ratio for AMP, ADP, and ATP in mutant (T-1) cells of Escherichia coli W, deficient in de novo purine biosynthesis at a point between IMP and 5-aminoimidazole-4-carboxiamide-1-β-D-ribofuranoside (AICAR), was 1:0.43:0.19. This ratio was approximately equal to the 5'-nucleotidase activity ratio in E. coli W cells. The order of inhibitory effect on [2-3H]ADP uptake by T-1 cells was adenine > adenosine > AMP > ATP. About 2-fold more radioactive purine bases than purine nucleosides were detected in the cytoplasm after 5 min in an experiment with [8-1?C]AMP and T-1 cells. Uptake of [2-3H]adenosine in T-1 cells was inhibited by inosine, but not in mutant (Ad-3) cells of E. coli W, which lacked adenosine deaminase and adenylosuccinate lyase. These experiments suggest that AMP, ADP, and ATP are converted mainly to adenine and hypoxanthine via adenosine and inosine before uptake into the cytoplasm by E. coli W cells.     

Performance evaluation and phylogenetic characterization of anaerobic fluidized bed reactors using ground tire and pet as support materials for biohydrogen production

This study evaluated two different support materials (ground tire and polyethylene terephthalate [PET]) for biohydrogen production in an anaerobic fluidized bed reactor (AFBR) treating synthetic wastewater containing glucose (4000 mg L⁻¹). The AFBR, which contained either ground tire (R1) or PET (R2) as support materials, were inoculated with thermally pretreated anaerobic sludge and operated at a temperature of 30 °C. The AFBR were operated with a range of hydraulic retention times (HRT) between 1 and 8 h. The reactor R1 operating with a HRT of 2 h showed better performance than reactor R2, reaching a maximum hydrogen yield of 2.25 mol H₂ mol⁻¹ glucose with 1.3 mg of biomass (as the total volatile solids) attached to each gram of ground tire. Subsequent 16S rRNA gene sequencing and phylogenetic analysis of particle samples revealed that reactor R1 favored the presence of hydrogen-producing bacteria such as Clostridium, Bacillus, and Enterobacter.     

Establishment of the evergreen broad-leaved tree species Castanopsis cuspidata in an abandoned secondary forest in western Japan

Recently, populations of Castanopsis cuspidata have often expanded into secondary forests in western Japan. To determine the establishment processes of this species, we analyzed its spatial distribution in a secondary forest dominated by Quercus variabilis and Quercus serrata that is located adjacent to a stand dominated by C. cuspidata. Saplings, defined as ≥30 cm stem length (SL) and <5 cm diameter at breast height (DBH), were abundant and their size distribution was inversely J-shaped, indicating continuous recruitment. Although seedlings (SL < 30 cm) and small saplings (30 ≤ SL < 50 cm) of C. cuspidata were aggregated near flowering trees of this species, some were found ≥40 m from the nearest adults, suggesting that there is animal-aided dispersal of acorns. The distribution of larger-sized individuals (≥100 cm SL) of C. cuspidata was unrelated to distance from the nearest flowering C. cuspidata or dominant Quercus species (≥5 cm DBH), but was associated with dead Pinus densiflora trees, which were abundant at the site. Thus, the establishment of C. cuspidata in this forest is controlled mainly by two factors, viz. patterns of acorn dispersal by animals, and forest disturbance regime (i.e., deaths of pine trees).