Regeneration processes of riparian Robiniapseudoacacia forests after clear-cutting were investigated through dendroecological and microsatellite polymorphism analyses. Age determination
of regenerated R.pseudoacacia trees based on the dendroecological analysis revealed that forests regenerating after clear-cutting were composed of trees
that mostly established within a few years after clear-cutting. This suggests that the stimulus to form new shoots was evoked
by clear-cutting but faded within a few years. Genet identification via the microsatellite polymorphism analysis showed that
ramet trees belonging to the same genet were distributed in a cluster. Almost all trees regenerated asexually through new
ramet formation on the cut stumps and residual horizontal roots after clear-cutting. AMOVA with microsatellite markers showed
that among- and within-population variations contributed 6 and 94% to the total variation, respectively, suggesting that R.pseudoacacia trees in the forests were initially established from seeds dispersed randomly from mother trees in a wide area. 相似文献
Molecular phylogenetic studies were carried out based on ITS-5.8S rDNA, the D1–D2 region of the large subunit rRNA gene, RPB2,
and combined data of D1–D2 and RPB2 as well as these three genes on 36 species among 7 genera for Lachnum and allied genera in the family Hyaloscyphaceae. In the combined data of all three regions, seven strongly supported clades
were obtained. The same clades were also recognized in most of the trees based on each gene, and the combined data of D1–D2
and RPB2, although some of them were not strongly supported. Four clades represented Albotricha, Brunnipila, Incrucipulum, and Lachnellula, respectively, whereas Lachnum was distributed to the remaining three clades. The molecular phylogenies strongly supported a group of species with granulate
hairs, and we suggest the concept of Lachnaceae should be restricted to these species. Based on the molecular phylogenetic
analysis, three new combinations—Incrucipulum longispineum, I. radiatum, and Lachnellula pulverulentum from Lachnum—are proposed. 相似文献
As part of a study aimed at determining the factors affecting overwintering habitat choice by Halyomorpha halys, we examined the behavioral response to light of diapausing adults (which have no reproductive activity) and non-diapausing
adults. Bugs were tested individually in a choice chamber (14, 18 and 24°C) containing a dark refuge with opaque (black) sides
and roof. Each bug’s position in the choice chamber was recorded at regular intervals. The results indicated that diapausing
bugs prefer to settle in a dark place (p < 0.05). This preference appeared to weaken at 24°C; however, this apparent trend was probably due to the greater overall
activity of the bugs under warmer conditions. In tests of non-diapausing bugs, lower proportions of the bugs were observed
inside the dark refuge at higher temperatures; however, the preference for dark places was exhibited under all temperature
conditions. Based on these results, we infer that H. halys adults have a fundamental preference for dark places whether or not they are in diapauses, which plays a main role in hiding
behavior. This preference becomes most obvious in the winter, with the decrease in behavioral activity resulting from lower
temperatures. We propose that this common preference for location is one of the factors responsible for the bugs’ convergence
on specific microhabitats and the overwintering aggregate formation of H. halys. 相似文献
The LYS49-PLA2s myotoxins have attracted attention as models for the induction of myonecrosis by a catalytically independent mechanism of action. Structural studies and biological activities have demonstrated that the myotoxic activity of LYS49-PLA2 is independent of the catalytic activity site. The myotoxic effect is conventionally thought to be to due to the C-terminal region 111-121, which plays an effective role in membrane damage. In the present study, Bn IV LYS49-PLA2 was isolated from Bothrops neuwiedi snake venom in complex with myristic acid (CH3(CH2)12COOH) and its overall structure was refined at 2.2 Å resolution. The Bn IV crystals belong to monoclinic space group P21 and contain a dimer in the asymmetric unit. The unit cell parameters are a = 38.8, b = 70.4, c = 44.0 Å. The biological assembly is a “conventional dimer” and the results confirm that dimer formation is not relevant to the myotoxic activity. Electron density map analysis of the Bn IV structure shows clearly the presence of myristic acid in catalytic site. The relevant structural features for myotoxic activity are located in the C-terminal region and the Bn IV C-terminal residues NKKYRY are a probable heparin binding domain. These findings indicate that the mechanism of interaction between Bn IV and muscle cell membranes is through some kind of cell signal transduction mediated by heparin complexes. 相似文献
Males use courtship signals to inform a conspecific female of their presence and/or quality, or, alternatively, to ‘cheat’ females by imitating the cues of a prey or predator. These signals have the single function of advertising for mating. Here, we show the dual functions of the courtship song in the yellow peach moth, Conogethes punctiferalis, whose males generate a series of short pulses and a subsequent long pulse in a song bout. Repulsive short pulses mimic the echolocation calls of sympatric horseshoe bats and disrupt the approach of male rivals to a female. The attractive long pulse does not mimic bat calls and specifically induces mate acceptance in the female, who raises her wings to facilitate copulation. These results demonstrate that moths can evolve both attractive acoustic signals and repulsive ones from cues that were originally used to identify predators and non-predators, because the bat-like sounds disrupt rivals, and also support a hypothesis of signal evolution via receiver bias in moth acoustic communication that was driven by the initial evolution of hearing to perceive echolocating bat predators. 相似文献
Invasive mammals include good tree climbers that use tree cavities for resting and nesting. Tree cavities are important but limited resources in most forests; thus, some invasive mammals can be serious competitors for native cavity-using species, especially cavity-nesting birds. Despite the potential impact, such inter-class competition has rarely been considered. We examined the possibility of resource competition for tree cavities between the invasive raccoon Procyonlotor and the native Ural owl Strixuralensis. Both species are nocturnal and use tree cavities during daytime. We assessed an overlap in cavity use for both species as an indication of potential competition by monitoring 341 cavities during their breeding season in a natural park in Hokkaido, Japan. Of 341 potentially available cavities, raccoons and Ural owls used 37 and 32, respectively. The characteristics of 58 cavities used by raccoons or owls were compared to 49 random cavities to determine if they selected cavities with certain characteristics. As predicted from a large amount of tree cavities and a low raccoon density in this managed forest, we did not find direct evidence of competition, such as physical interaction, intrusion to cavities, or habitat segregation. Cavity types used by both species overlapped considerably in terms of height, entrance size, depth, and other characteristics: their habitats were widely overlapped. Further, in four cavities, one species was replaced by the other. Given the similar habitat requirements, the invasive raccoon could be a potential competitor for Ural owl when raccoon density increases and/or cavity availability decreases, which is the case for many forests in Japan. This study suggests that potential threats of resource competition among not only closely but also distantly related taxa should be taken into consideration when studying the impacts of invasive species. 相似文献
Vitamin D deficiency has been reported to be common in patients with rheumatoid arthritis (RA) who have a higher prevalence of osteoporosis and hip fracture than healthy individuals. Genetic variants affecting serum 25-hydroxyvitamin D (25(OH)D) concentration, an indicator of vitamin D status, were recently identified by genome-wide association studies of Caucasian populations. The purpose of this study was to validate the association and to test whether the serum 25(OH)D-linked genetic variants were associated with the occurrence of hip fracture in Japanese RA patients.
Methods
DNA samples of 1,957 Japanese RA patients were obtained from the Institute of Rheumatology, Rheumatoid Arthritis (IORRA) cohort DNA collection. First, five single nucleotide polymorphisms (SNPs) that were reported to be associated with serum 25(OH)D concentration by genome-wide association studies were genotyped. The SNPs that showed a significant association with serum 25(OH)D level in the cross-sectional study were used in the longitudinal analysis of hip fracture risk. The genetic risk for hip fracture was determined by a multivariate Cox proportional hazards model in 1,957 patients with a maximum follow-up of 10 years (median, 8 years).
Results
Multivariate linear regression analyses showed that rs2282679 in GC (the gene encoding group-specific component (vitamin D binding protein)) locus was significantly associated with lower serum 25(OH)D concentration (P = 8.1 × 10-5). A Cox proportional hazards model indicated that rs2282679 in GC was significantly associated with the occurrence of hip fracture in a recessive model (hazard ratio (95% confidence interval) = 2.52 (1.05-6.05), P = 0.039).
Conclusions
A two-staged analysis demonstrated that rs2282679 in GC was associated with serum 25(OH)D concentration and could be a risk factor for hip fracture in Japanese RA patients. 相似文献
Parkinson's disease (PD) is a common neurodegenerative disease, but its pathogenesis remains elusive. A mutation in ubiquitin C‐terminal hydrolase L1 (UCH‐L1) is responsible for a form of genetic PD which strongly resembles the idiopathic PD. We previously showed that 1‐(3′,4′‐dihydroxybenzyl)‐1,2,3,4‐tetrahydroisoquinoline (3′,4′DHBnTIQ) is an endogenous parkinsonism‐inducing dopamine derivative. Here, we investigated the interaction between 3′,4′DHBnTIQ and UCH‐L1 and its possible role in the pathogenesis of idiopathic PD. Our results indicate that 3′,4′DHBnTIQ binds to UCH‐L1 specifically at Cys152 in vitro. In addition, 3′,4′DHBnTIQ treatment increased the amount of UCH‐L1 in the insoluble fraction of SH‐SY5Y cells and inhibited its hydrolase activity to 60%, reducing the level of ubiquitin in the soluble fraction of SH‐SY5Y cells. Catechol‐modified UCH‐L1 as well as insoluble UCH‐L1 were detected in the midbrain of 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine‐treated PD model mice. Structurally as well as functionally altered UCH‐L1 have been detected in the brains of patients with idiopathic PD. We suggest that conjugation of UCH‐L1 by neurotoxic endogenous compounds such as 3′,4′DHBnTIQ might play a key role in onset and progression of idiopathic PD.
The saccharification of agricultural woody wastes was studied using a commercial enzyme preparation, Cellulase onozuka, derived from Trichoderma viride or the solid culture extracts of the fungus. With the intention of producing sugar at low cost, a simple procedure of enzymatic saccharification of rice straw, bagasse, and sawdust was studied. Delignifying methods of these wastes were investigated using dilute sodium hydroxide solution and dilute peracetic acid. Rice straw and bagasse were effectively delignified by boiling in a 1% sodium hydroxide solution for 3 hr or by autoclaving at 120 degrees C in a 1% sodium hydroxide solution for 1 hr. The sawdust from a broad leaved tree (Machilus thunbergii) was delignified by autoclaving at 120 degrees C in a 1% sodium hydroxide solution for 1 hr and by subsequent boiling in diluted 1/5 peracetic acid for 1 hr. This type of sawdust was also delignified by boiling in 1/5 peracetic acid for 1 hr and by subsequent autoclaving at 120 degrees C in a 1% sodium hydroxide solution for 1 hr. The sawdust from a coniferous tree (Cryptomeria japonica) was delignified by boiling in 1/5 peracetic acid for 1 hr and by subsequent autoclaving at 120 degrees C in a 1% sodium hydroxide solution for 1 hr; however, the successive treatment by autoclaving with alkali solution and subsequent boiling with diluted peracetic acid failed to bring about the desired effect. The saccharification of delignified rice straw, bagasse, and sawdust was examined using Cellulase onozuka, wheat bran or rice straw solid culture at various substrate concentrations, resulting in the formation of 5 to 10% sugar solutions after incubation at pH 5.0, 45 degrees C for 48 hr. The optimum substrate concentration existed at around 10%. Reuse of cellulase solution and resaccharification of residual sawdust were considered to be inadequate. 相似文献