<Emphasis Type="Italic">Bursaphelenchus mucronatus</Emphasis> (Nematoda: Aphelenchoididae) vectored by <Emphasis Type="Italic">Monochamus </Emphasis><Emphasis Type="Italic">urussovi</Emphasis> (Coleoptera: Cerambycidae) in Hokkaido,Japan

Bursaphelenchus mucronatus Mamiya et Enda has been recovered for the first time from adults of the cerambycid beetle, Monochamus urussovi (Fischer), in Hokkaido, Japan. The nematode was also recovered from the inner bark of Picea jezoensis (Siebold et Zuccarini) Carrière and Abies sachalinensis (Fr Schmidt) Masters infested with M. urussovi larvae. PCR–RFLP analysis indicated that B. mucronatus in Hokkaido is the European type.     

Relationship between prey utilization and growth variation in hatchery‐reared Pacific bluefin tuna,Thunnus orientalis (Temminck et Schlegel), larvae estimated using nitrogen stable isotope analysis

In mass culture of Pacific bluefin tuna Thunnus orientalis, a marked growth variation is observed after they start feeding at 6–7 mm in body length (BL) on yolk‐sac larvae of other species, and the growth variation in tuna larvae is a factor leading to the prevalence of cannibalism. To examine the relationship between prey utilization and growth variation, nitrogen stable isotope ratios (δ¹⁵N) of individual larvae were analysed. A prey switch experiment was conducted under two different feeding regimes: a group fed rotifers (rotifer fed group), and a group fed yolk‐sac larvae of spangled emperor, Lethrinus nebulosus (fish fed group) from 15 days after hatching (6.87 mm BL). The fish fed group showed significantly higher growth than the rotifer fed group. Changes in the δ¹⁵N of the fish fed group were expressed as an exponential model and showed different patterns from those of the rotifer fed group. The δ¹⁵N of fast‐growing tuna larvae collected in an actual mass culture tank after the feeding of yolk‐sac larvae was significantly higher than those of the slow‐growing larvae, indicating that slow glowing larvae depended largely on rotifers rather than the yolk‐sac larvae.     

Effects of Whole Grain Wheat Bread on Visceral Fat Obesity in Japanese Subjects: A Randomized Double-Blind Study

Metabolic syndrome is a risk factor for cardiovascular diseases and has become increasingly common in Japan. Epidemiological studies show inverse associations between intake of whole wheat grains and metabolic syndrome, but few dietary intervention trials have investigated the effect of whole wheat grain consumption. It was investigated whether a diet in which refined wheat bread (RW diet) was substituted by whole grain wheat bread (WW diet) would reduce visceral fat obesity in Japanese subjects. A randomized double-blind placebo-controlled intervention study was conducted in 50 Japanese subjects with body mass index (BMI)?≥?23 kg/m². Subjects were randomly assigned WW (WW group) or RW diets (RW group) for 12 weeks. Blood samples and computed tomography scans were obtained every 6th week. The WW group showed decrease (?4 cm²) in visceral fat area (VFA) (p <?0.05), whereas the RW group showed no significant changes. These time-dependent changes were significantly different between the groups. WW diet led to significant and safe reductions in VFA in subjects with BMI?≥?23 kg/m². WW diet may contribute to preventing visceral fat obesity.     

Effects of vertically transferred 3,3',4,4',5-pentachlorobiphenyl on gene expression in the ovaries of immature Sprague-Dawley rats

We have previously shown that 3,3',4,4',5-pentachlorobiphenyl (PCB-126) vertically transferred from dams potentially exerts a direct effect on the ovaries of offspring and adversely affects female puberty. To investigate its toxicological targets in ovarian tissues, mRNAs encoding representative peptides that regulate follicular development in granulosa cells, theca cells, and oocytes were quantified using ovaries collected on postnatal days (PND) 5, 15, and 24 from the offspring of dams administered oral doses of 0, 1 or 3 microg/kg PCB-126 starting 2 weeks prior to mating and continuing until 20 days after delivery. Quantification using the real-time RT-PCR method revealed that PCB-126 lowered the amounts of mRNAs that encoded the inhibin alpha- and inhibin/activin beta A-subunits from PND 15 onwards; the amounts of mRNAs for inhibin/activin beta B-subunit, follicle-stimulating hormone (FSH) receptor, and aromatase on PND 15; and the amounts of luteinizing hormone receptor mRNA on PND 24 compared with those of the age-matched controls. In contrast, no differences were noted for mRNAs encoding c-kit, growth differentiation factor-9, bone morphogenetic protein-15, or kit ligand for any of the age groups examined. The serum FSH level on PND 24 was higher than that in the control. Since the earliest effects on the mRNAs in the rat ovaries were observed in those expressed in the granulosa cells of the growing follicles after the antral follicles had developed, molecules in granulosa cells but not in oocytes during the early stages of the antral follicles might be the primary targets of vertically transferred PCB-126.     

Distribution,growth and hatch date of juvenile Pacific bluefin tuna <Emphasis Type="Italic">Thunnus orientalis</Emphasis> in the coastal area of the sea of Japan

ABSTRACT:   Mid-water trawl surveys were conducted from late August to late September in 1999 and 2004 in order to investigate the distribution pattern, hatch date, and growth of juvenile Pacific bluefin tuna Thunnus orientalis in the Sea of Japan. Juveniles were collected at the stations where ambient water temperature (mean water temperature from surface to 30 m deep, WT₀₋₃₀) was 23.4–25.9°C, and most of them were found in waters where WT₀₋₃₀ was higher than 24°C. Sampled juveniles ranged 108–280 mm fork length. Based on otolith analysis, they were estimated to grow to approximately 180 and 250 mm at 60 and 90 days old, respectively, and showed similar growth to that of Atlantic bluefin tuna in the Mediterranean Sea. The back-calculated hatch date of the samples was mostly in July and most juveniles spawned in the Sea of Japan.     

Cutaneous hybrid cyst in a sprague-dawley rat

This report describes a spontaneous hybrid cyst in a Sprague-Dawley (SD) rat. A 52-week-old, male SD rat had a cutaneous cyst on the left mystacial pad. Histologically, the cyst wall showed infundibular differentiation with keratohyalin granules in the granular layer and matrical differentiation comprising basaloid epithelial cells with trichohyalin granules. The cyst cavity was filled with lamellar, flaky keratin and aggregates of shadow cells. Immunohistochemically, the infundibular-type epithelium was positive for cytokeratin (CK) AE1/AE3, CK KL1 and CK14 but negative for CK15, whereas the matrical-type epithelium was negative for all four CK isoforms examined. These immunohistochemical properties of the infundibular- and matrical-type epithelia were similar to those of the infundibulum and inferior segment of normal hair follicles, respectively. Based on these findings, the cyst was diagnosed as a hybrid cyst, comprising more than one type of cyst arising from various parts of the pilosebaceous unit.     

The TIR–NBS but not LRR domains of two novel N-like proteins are functionally competent to induce the elicitor p50-dependent hypersensitive response

The tobacco N protein recognizes the helicase domain (p50) of the Tobacco mosaic virus (TMV) replicase as an elicitor and mediates hypersensitive response (HR). We obtained two cDNA clones encoding novel N-like (NL) proteins NL-C26 and NL-B69 from Nicotiana tabacum cv. Samsun NN. NL-C26 and NL-B69 had a Toll-interleukin-1 receptor/nucleotide-binding site/leucine-rich repeat (TIR–NBS–LRR) structure and showed 78% and 73% identities to N, respectively. The NL-C26 and NL-B69 genes were also expressed in N. tabacum cv. Samsun nn, which lacks the N gene. Unlike N, NL-C26 and NL-B69, when coexpressed with p50, failed to induce HR on the sites of agroinfiltration in Samsun nn leaves. However, the elicitor-dependent HR in Samsun nn was induced efficiently by chimeric N proteins with the continuous TIR–NBS domains of NL-C26 and NL-B69. On the other hand, the efficiency of HR induction varied significantly among chimeric N proteins with either of the TIR and NBS domains of the NL proteins. In contrast, chimeras carrying the LRR domains of the NL proteins did not induce HR. Thus, the TIR–NBS domains of NL-C26 and NL-B69 could functionally adapt to the LRR domain of N, which may determine the specificity for the elicitor. We speculate that the NL genes are potential HR-inducing resistance genes for undetermined pathogens other than TMV.     

Cropland soil–plant systems control production and consumption of methane and nitrous oxide and their emissions to the atmosphere

Croplands are an important source of atmospheric methane (CH₄) and nitrous oxide (N₂O), both potent greenhouse gases. Reduction of cropland CH₄ and N₂O emissions is expected to mitigate climate change. However, large uncertainty remains in the assessment and prediction of these emissions, which prevents us from establishing appropriate mitigation options and strategies. The uncertainty is attributed mainly to the high spatiotemporal variability in emissions (e.g., emission spikes of N₂O). Understanding and quantifying how hotspots of CH₄ and N₂O production in soil and then hot moments of their emissions occur would help reduce the uncertainty. This review focuses on soil–plant systems, particularly the rhizosphere, as possible hotspots of production and consumption of CH₄ and N₂O. It is well known that the rhizosphere controls CH₄ emission strongly, though each process of production and consumption remains to be quantified. On the other hand, surprisingly little attention has been paid to N₂O, besides the fact that plant roots strongly control nitrification and denitrification. We review the current knowledge of cropland CH₄ and N₂O emissions, and conclude that soil–plant interactions strongly affect cropland emissions of both gases, in which functions of plant roots affecting biogeochemical factors (e.g., availability of oxygen, labile organic carbon and inorganic nitrogen) in the rhizosphere and phenological changes are particularly important. In relation to the status of current knowledge, we discuss future research needed.     

Dark adaptation time in canine electroretinography using a contact lens electrode with a built-in light source

The purpose of this study was to evaluate the dark adaptation time in canine electroretinography (ERG) using a contact lens electrode with a built-in LED. Twelve eyes of six normal laboratory beagle dogs were used and exposed to steady room light at 500 lux for 30 min for light adaption. ERG was recorded at different time points during dark adaptation in sedated and light-adapted beagles. The stimulus intensity was 0.0096 cd/m²/sec. The b-wave amplitude increased significantly until 25 min of dark adaptation, whereas no significant changes in amplitudes were observed after 30 min. Dark adaptation for more than 25 min would be necessary for accurate ERG in canine ERG using a contact lens electrode with a built-in LED.     

Field study of hind limb claw lesions and claw measures in sows

We investigated the associations of hind limb claw lesions with claw measures and reproductive performance of sows on a commercial breeding farm. We used a five‐point scale (score of 0–4) for each hind limb claw region to generate a claw lesion score (CLS). Of 110 sows, 1.8% had no hind claw lesions, and the remaining 98.2% had at least one. The proportions of sows with a CLS of 2 and 3 were 49.1% and 3.6%, respectively. The junction region had the highest frequency of a CLS of ≥ 2 (P < 0.05). The mean toe length was 45.0 ± 0.4 to 46.4 ± 0.4 mm. Sows with the highest CLS of ≥ 2 in the lateral claw had longer sole dimensions than did sows with the highest CLS of ≤ 1 (P < 0.05). There were no significant differences in claw width or height between sows with the highest CLS of ≥ 2 and ≤ 1. There was also no difference in reproductive performance between sows with the highest CLS of ≥ 2 and ≤ 1. In conclusion, most sows had hind claw lesions. The association between CLS and claw measures indicates that the sole length can be used as an indicator of claw lesions.