Males with short horns spent more time mating in the Japanese horned beetle Allomyrina dichotoma

We examined the relationships between male body and horn sizes and mating duration in the Japanese horned beetle, Allomyrina dichotoma. Smaller males possessing shorter horns spent more time for copulation with a female and mounting the female without copulation. The results of multiple regression analyses indicate that the horn length is a determining factor for the time spent by the males during mating. A previous study has documented that the horn length of male A. dichotoma primarily determined the outcomes of aggressive male–male interactions; hence, predicts access to females. Therefore, instead of fighting for females, males possessing short horns may maximize their fertilization success by mating longer with the few females they have access to.     

6-Carboxy-5,7-diarylcyclopenteno[1,2-b]pyridine derivatives: a novel class of endothelin receptor antagonists

Compounds (2-5) with a 6-carboxy-5,7-diarylcyclopentenopyridine skeleton were designed, synthesized, and identified as a new class of potent non-peptide endothelin receptor antagonists. The regio-isomer 2 was found to show potent inhibitory activity with an IC(50) value of 2.4 nM against (125)I-labeled ET-1 binding to human ET(A) receptors and a 170-fold selectivity for ET(A) over ET(B) receptors. Furthermore, 2 displayed more potent in vivo activity than did the indan-type compound 1 in a mouse ET-1 induced lethality model, suggesting the potential of 2 as a new lead structure. Derivatization on substituted phenyl groups at the 5- and 7-positions of 2 revealed that a 3,4-methylenedioxyphenyl group at the 5-position and a 4-methoxyphenyl group at the 7-position were optimal for binding affinity. Further derivatization of 2 by incorporating a substituent into the 2-position of the 4-methoxyphenyl group led to the identification of a more potent ET(A) selective antagonist 2p with an IC(50) value of 0.87 nM for ET(A) receptors and a 470-fold selectivity. In addition, 2p showed highly potent in vivo efficacy (AD(50): 0.04 mg/kg) in the lethality model.     

Nation-wide litter fall data from 21 forests of the Monitoring Sites 1000 Project in Japan

This data paper reports litter fall data collected in a network of 21 forest sites in Japan. This is the largest litter fall data set freely available in Japan to date. The network is a part of the Monitoring Sites 1000 Project launched by the Ministry of the Environment, Japan. It covers subarctic to subtropical climate zones and the four major forest types in Japan. Twenty-three permanent plots in which usually 25 litter traps were installed were established in old-growth or secondary natural forests. Litter falls were collected monthly from 2004, and sorted into leaves, branches, reproductive structures and miscellaneous. The data provide seasonal patterns and inter-annual dynamics of litter falls, and their geographical patterns, and offer good opportunities for meta-analyses and comparative studies among forests.     

Geographical variation in the early regeneration process of Siebold's Beech (Fagus crenata BLUME) in Japan

The causes and timing of seed death in early regeneration process of Siebold's beech (Fagus crenata Blume) was studied at 15 sites along a snowfall gradient in Japan, in order to clarify why the seedling density of the species has geographic difference remarkably. Seed production did not significantly differ along the snowfall gradient. Pre-dispersal seed mortality by insect damage was higher at sites with light snowfall than at sites with heavy snowfall, but this only seemed to be a minor factor influencing the population. A large proportion of the viable nuts that fall in autumn ware killed in winter before germination. Winter mortality was much higher at sites with thin snow cover than that at sites with thick snow cover, and this factor was strongly correlated with the geographic variation of seedling regeneration probability. There was little seed mortality by winter desiccation. The main factor contributing to the geographic difference seemed to be a seed predation by rodents in winter. Deep snow cover may reduce the success of rodents finding seeds in winter. Thus the observed relationship between snowpack depth and early mortality may be due to an indirect effect through the process of seed predation.p>     

Comparative demography of three coexisting Acer species in gaps and under closed canopy

Questions: 1. Is there a trade‐off between gap dependency and shade tolerance in each of the life‐history stages of three closely related, coexisting species, Acer amoenum (Aa), A. mono (Am) and A. rufinerve (Ar)? 2. If not, what differences in life‐history traits contribute to the coexistence of these non‐pioneer species? Location: Ogawa Forest Reserve, a remnant (98 ha), species‐rich, temperate deciduous forest in central Japan (36°56’ N, 140°35’ E, 600 ‐ 660 m a.s.l.). Methods: We estimated the demographic parameters (survival, growth rate and fecundity) by stage of each species growing in gaps and under closed canopy through observations of a 6‐ha permanent plot over 12 years. Population dynamics were analysed with stage‐based matrix models including gap dynamics. Results : All of the species showed high seedling and sapling survival rates under closed canopies. However, demographic parameters for each growth stage in gaps and under closed canopies revealed inter‐specific differences and ontogenetic shifts. The trade‐off between survival in the shade and growth in gaps was detected only at the small sapling stage (height < 30 cm), and Ar had the highest growth rate both in the shade and in the gaps at most life stages. Conclusions: Inter‐specific differences and ontogenetic shifts in light requirements with life‐form differences may contribute to the coexistence of the Acer species in old‐growth forests, with Aa considered a long‐lived sub‐canopy tree, Am a long‐lived canopy tree, and Ar a short‐lived,‘gap‐phase’ sub‐canopy tree.     

Analysis of the disassortative mating pattern in a heterodichogamous plant, <Emphasis Type="Italic">Acer mono</Emphasis> Maxim. using microsatellite markers

Heterodichogamy is a form of sex expression in which protandrous and protogynous individuals coexist, and is considered to be a mechanism that avoids selfing and promotes disassortative mating. We examined mating patterns in a heterodichogamous maple, Acer mono, using microsatellite markers. Parentage analysis revealed a selfing rate of only 9.8%. Disassortative mating between flowering types significantly exceeded within-type mating, but the mating patterns were better explained by flowering phenology (i.e., the temporal overlap between the female and male stages). Heterodichogamy in A. mono thus appears to promote outcrossing without requiring obligate self- or cross-incompatibility systems, although it did not guarantee disassortative mating. Multiple-regression analysis suggested that successful reproduction of pollen parents significantly increased with increased flower production and reciprocal flowering synchrony, but decreased only marginally with mating distance, although the distribution of mating distances suggested leptokurtic dispersal of pollen.     

Effects of population density, sex morph, and tree size on reproduction in a heterodichogamous maple, Acer mono, in a temperate forest of Japan

The effects of local population density, sex morph [protogynous (PG) or protandrous (PA)], and individual tree size on the demographic processes of seed production were investigated in a heterodichogamous maple, Acer mono Maxim. var. Marmoratum (Nichols.) Hara f. dissectum, in a temperate forest of Japan. As the distance from conspecific reproductive adults increased, the percentage of immature seed fall and empty seeds increased significantly, indicating higher pollination success along with local population density. Although the difference was not distinct, pollination success was affected by the local population density of the reciprocal sex morph rather than that of both sex morphs. The trees at higher local population density sites suffered higher seed mortality due to predation and decay, and tended to produce smaller seeds. Thus, the impacts of local population density operated both positively and negatively on reproduction. As a factor of individual traits, tree size scarcely affected any demographic processes. On the other hand, sex morph did affect pollination success. Trees of PG type had lower immature seed fall than those of PA type, suggesting that the former has higher efficiency of pollen acceptance than the latter. The results on seed demography presented here partly support previous suggestions that heterodichogamous plants exhibit reciprocal cross-pollination and gender specialization as reproductive traits.     

Hepatic bile and pancreatic exocrine secretions evoked by gastrointestinal peptides in sheep

The secretory response of hepatic bile and exocrine pancreas to gastrointestinal peptides has been studied in chronically cannulated sheep. Pancreatic juice flow and protein output were evoked dose dependently by intraportal injection of secretin, CCK-8, caerulein, VIP and neurotensin. However, biliary secretion was evoked by only secretin. Biliary and pancreatic exocrine secretions were enhanced by delivered gastric juice into the duodenum as followed by the increased plasma concentration of immunoreactive secretin (IRS). Results suggest that secretin is the major peptide that regulates pancreatic exocrine secretion and hepatic bile production in the sheep.     

Conjugal Transformation and Transposon and Chemical Mutagenesis of Gram-Negative Selenate-Respiring <Emphasis Type="Italic">Citrobacter</Emphasis> sp. Strain JSA

Conjugal mating between selenate-reducing Citrobacter sp. strain JSA and Escherichia coli S17-1 bearing pSUP2021 allowed transposon mutagenesis and chromosomal transformation. Kanamycin-resistant transconjugants were obtained successfully by this method from a freshwater selenate-respiring Citrobacter sp. strain JSA. The maximum frequency of kanamycin-resistant Tn5 transconjugants was 3.6 × 10⁻⁶ per recipient of this strain. Of these transconjugants, eight strains of selenate reduction-deficient transconjugants living by nitrate reduction were obtained in the strain JSA. Moreover, the same phenotype of deficient mutant was created by chemical mutagenesis with ethylmethanesulfonate. The results strongly indicate that selenate reducing anaerobic respiration was independent of nitrate reduction in the Citrobacter sp. isolate strain JSA.     

Cloning of cDNA for UDP-glucose pyrophosphorylase and the expression of mRNA in rice endosperm

Rice endosperm UDP-glucose pyrophosphorylase (UGPase) cDNA clones were isolated by screening a lambda ZAP II library prepared from poly (A(+)) RNA of japonica rice (cv Sasanishiki) endosperm with a probe of potato UGPase cDNA. One cDNA clone, possessing about 1,700 nucleotides, contained the complete open reading frame of rice UGPase. At the nucleotide-sequence level, the UGPase cDNA of rice endosperm had high homology with the UGPase cDNA of barley endosperm (84%) and potato tuber (71%). The calculated molecular weight (50 kDa) agrees with the value determined by SDS-PAGE (51 kDa). At the amino-acid sequence level, rice UGPase has high homology with the UGPase of barley (92%) and potato (85%). The enzyme contained conserved sequence elements which are thought to be involved in substrate binding and catalytic activity. A Southern-blot analysis indicated that the gene existed as a single copy. Expression of the enzyme in rice endosperm examined by Northern-blot analysis was high at 10-15 days after heading.