Seasonal changes and controlling factors of gross N transformation in an evergreen plantation forest in central Japan

We conducted a year-round measurement of gross N transformation rates using the ¹⁵N dilution method, and analyzed seasonal changes and the mechanisms regulating gross N transformation in the Kiryu Experimental Forest in central Japan. While soil microbial biomass C (SMB-C) decreased from the dormant to growing seasons at the organic (O) horizon, no significant trend was observed in SMB-N. This resulted in SMB-C/N being high in the dormant season and low in the growing season, and suggests that the microbial composition changed seasonally. No clear seasonal trend was found in gross NH₄ ⁺ production rates at either the O or surface mineral soil horizons. In contrast, the NH₄ ⁺ consumption rate varied seasonally, with high values in January and April during the dormant season and low values in July and October during the growing season. There was no clear trend in seasonal fluctuation of net NH₄ ⁺ production rates. Gross NH₄ ⁺ production and gross NH₄ ⁺ consumption rates were 10 times greater than the gross nitrification rate. Almost all of the produced NH₄ ⁺ was immobilized, indicating that N tightly cycles at this study site. Considered together with results of the gross N transformation rates, the dominance of high SMB-C/N microbes might stimulate immobilization in the dormant season. At this study site, the change in microbial composition likely influences gross N transformation through immobilization efficiency.     

Genetic differentiation between summer and autumn maturing cultivars of soybean (Glycine max (L.) Merrill) in Kyushy district of Japan

Summary 135 soybean landraces and pure line selections from Kyushu district fo Japan were assayed for isozyme and seed protein loci in order to determine the genetic structure groups of summer and autumn maturing cultivars. Out of the 16 tested loci, Dial, Enp, Estl, and Ti exhibited a marked difference in allelic frequency between both groups. The summer cultuvar groups had a high frequency for Dial-b, Enp-b, Estl-a and Ti-b, whereas Dial-a, Enp-a, Estl-b, and Ti-a were predominant in the autumn groups. The analysis of multi-locus genotypes revealed that both groups mostly consisted of different multi-locus genotypes. The allelic combination Dial-b Enp-b Estl-a Ti-b was most frequently observed in the summer cultivars, whereas four genootypes, Dial-a Enp-a Estl-a Ti-a, Dial-a Enp-a Estl-b Ti-a, Dial-a Enp-b Estl-b and Dial-a Enp-a Estl-b Ti-b, occupied most of the autumn cultivars. These results indicated that both groups were appreciably differentiated from each other. The summer cultivar groups also included a few accessions having the multi-locus genotypes observed predominantly in the autumn groups or Acol-b charcteristic of the landraces native to northern Japan. It seems likely that the summer cultivar groups was not phyletically derived from a single common ancestor, but partly involves the landraces with early maturity derived from northern Japan. Dial, Enp, Estl and Ti are useful genetic markers ot trace the origin and dissemination paths of Japanse soybean landraces.     

Evaluation of estimates of crown condition in forest monitoring: comparison between visual estimation and automated crown image analysis

• Context  

In long-term forest monitoring, tree crown condition has been visually rated to diagnose tree vigor and forest condition. However, visual estimates are subjective. A semiautomatic image analysis system, called CROCO, was developed to estimate crown condition quantitatively. CROCO calculates a DSO value which decrease with increasing crown transparency.     

Combined use of a synthetic trail pheromone and insecticidal bait provides effective control of an invasive ant

BACKGROUND: Except for sex pheromones, use of pheromones in pest management has been largely unexplored. A high concentration of trail pheromone disrupts ant trail following and foraging, and thus synthetic trail pheromone can be a novel control agent for pest ants. In this study, a year‐long treatment of small areas (100 m² plots of urban house gardens) with synthetic trail pheromone, insecticidal bait or both was conducted to develop a novel control method of the invasive Argentine ant Linepithema humile (Mayr). RESULTS: The ant population could be maintained lower than or similar to the initial level only by combined treatment with synthetic trail pheromone and insecticidal bait. Actually, the ant population was nearly always lowest in combination treatment plots. Throughout the study period, the ant population in plots treated with either one of synthetic trail pheromone or insecticidal bait remained similar to no‐treatment plots. CONCLUSIONS: Combination treatment may be a more effective and environmentally friendly method for controlling invasive ants than conventional methods. Extermination of ants by insecticidal bait and inhibition of re‐infestation by pheromone may be the mechanism of the combination effect. This is the first study to show a significant effect of synthetic trail pheromone on ant population. Copyright © 2011 Society of Chemical Industry     

Visfatin: a protein secreted by visceral fat that mimics the effects of insulin

Fat tissue produces a variety of secreted proteins (adipocytokines) with important roles in metabolism. We isolated a newly identified adipocytokine, visfatin, that is highly enriched in the visceral fat of both humans and mice and whose expression level in plasma increases during the development of obesity. Visfatin corresponds to a protein identified previously as pre-B cell colony-enhancing factor (PBEF), a 52-kilodalton cytokine expressed in lymphocytes. Visfatin exerted insulin-mimetic effects in cultured cells and lowered plasma glucose levels in mice. Mice heterozygous for a targeted mutation in the visfatin gene had modestly higher levels of plasma glucose relative to wild-type littermates. Surprisingly, visfatin binds to and activates the insulin receptor. Further study of visfatin's physiological role may lead to new insights into glucose homeostasis and/or new therapies for metabolic disorders such as diabetes.     

Food habits of great cormorant Phalacrocorax carbo hanedae at Lake Biwa, Japan, with special reference to ayu Plecoglossus altivelis altivelis

ABSTRACT:   The recent increase in numbers of individuals of a piscivorous bird, the great cormorant Phalacrocorax carbo hanedae , around Lake Biwa has affected the commercial catch of ayu Plecoglossus altivelis altivelis . The food habits of the bird were studied based on 66 stomachs in 1998 and 2001–2002, and a seasonal variation in food contents was observed. The proportion of ayu in stomachs increased after April, and became most dominant during July and August (0.62 in proportion of weight, 0.85 in frequency of occurrence). In contrast, ayu was not found in the stomachs after late October. The increase of ayu in individuals and density in the surface layer of the pelagic zone of the lake during spring was considered as a trigger for the change of the food habits of the birds. The feeding impact of great cormorant on ayu in Lake Biwa was estimated to be approximately 46 t during April to June, and 310 t in July and August. During the main period for the commercial ayu catch (November to the following June), the estimated mass consumed by the bird is much smaller in comparison with the commercial catch.     

Strawberry cultivar identification based on hypervariable SSR markers

We genotyped strawberry cultivars by two newly selected and two previously reported SSR markers. All four markers produced interpretable electropherograms from 75 accessions consisting of 72 Fragaria × ananassa cultivars or lines and three octoploid Fragaria species accessions. These SSR markers were highly polymorphic; in particular, one of the newly developed markers, FxaHGA02P13, was capable of distinguishing all of the accessions except for a mutant strain that was derived from another accession in the set. When two markers were combined, all 48 full-sib individuals could be distinguished. Fingerprinting patterns were reproducible between multiple samples, including the leaves, sepals, and fruit flesh of the same accession. Principal-coordinate analysis of the 75 accessions detected several groups, which reflect taxon and breeding site. Together with other available markers, these SSR markers will contribute to the management of strawberry genetic resources and the protection of breeders’ rights.     

Brainstem Auditory Evoked Responses Elicited by Tone-Burst Stimuli in Clinically Normal Dogs

Brainstem auditory evoked responses (BAERs) to click and tone-burst stimuli (0.5, 1, 2, 4, and 8 kHz) were recorded from 32 ears in 16 adult Beagles. BAERs were used to establish a normative database and describe response thresholds and latencies (wave I-IV) for the different stimuli. The frequencies of sound used were 8, 4, 2, 1, and 0.5 kHz. Sound stimuli were delivered by a closed headphone and masking stimuli were not applied. The BAER waveforms obtained were similar to those reported previously, except for a frequency-following response evoked by 1-kHz tone-bursts. The threshold was lowest when clicks and 4-kHz tone-bursts were used. Significant differences were observed between the mean values of the peak latencies for clicks and 4-and 8-kHz tone-bursts. The tone-burst stimulation used in our experiment was shown to be an appropriate method for detecting the BAERs. Thus, for investigating the frequency-specificity of the auditory sense, BAER data obtained using tone-burst sound in dogs may be meaningful.     

Furosemide loading test in a case of homozygous solute carrier family 12, member 1 (SLC12A1) mutation (g.62382825G>A,p.Pro372Leu) in Japanese Black cattle

Hydrallantois is the excessive accumulation of fluid in the allantoic cavity in a pregnant animal and is associated with fetal death. We recently identified a recessive missense mutation in the solute carrier family 12, member 1 (SLC 12A1 ) gene (g.62382825G>A, p.Pro372Leu) that is associated with hydrallantois in Japanese Black cattle. Unexpectedly, we found a case of the homozygous risk‐allele for SLC 12A1 in a calf, using a PCR ‐based direct DNA sequencing test. The homozygote was outwardly healthy up to 3 months of age and the mother did not exhibit any clinical symptoms of hydrallantois. In order to validate these observations, we performed confirmation tests for the genotype and a diuretic loading test using furosemide, which inhibits the transporter activity of the SLC 12A1 protein. The results showed that the calf was really homozygous for the risk‐allele. In the homozygous calf, administration of furosemide did not alter urinary Na⁺ or Cl^? levels, in contrast to the heterozygote and wild‐type calves in which these were significantly increased. These results demonstrate that the SLC 12A1 (g.62382825G>A, p.Pro372Leu) is a hypomorphic or loss‐of‐function mutation and the hydrallantois with this mutation shows incomplete penetrance in Japanese Black cattle.