The Kidneys of Infant Mice are not Sensitive to the Food Mycotoxin Contaminant Nivalenol

Nivalenol (NIV) is a trichothecene mycotoxin produced by Fusarium fungi that frequently contaminates agricultural commodities. Dietary administration of NIV to adult mice affects the renal glomeruli, but data about NIV toxicity in human infants are limited. To evaluate the effects of NIV on infant kidneys, 3-week-old male ICR-derived glomerulonephritis (ICGN) and ICR mice were administered 0, 4, 8 or 16 ppm NIV in diet for 4 weeks, and their renal status was compared with age-matched or adult ICR mice. In ICGN mice, the number of glomeruli showing mesangial expansion and α-smooth muscle actin (SMA)-positive mesangial cells was higher with 16 ppm NIV compared with controls. No other significant differences were observed in ICGN mice. In infant ICR mice, the IgA serum concentrations were significantly elevated without glomerular morphological changes in the 16 ppm NIV group. There was no difference in NIV sensitivity in the kidneys of infant ICGN and ICR mice. These data suggest that the kidneys in infant mice are not sensitive to nivalenol under the present conditions.     

Identification of herds with cattle persistently infected with bovine viral diarrhea virus by virological evaluation of three calves

For the identification of herds with cattle persistently infected (PI) with bovine viral diarrhea virus, 1,272 animals from 20 herds were subjected to serum neutralizing (SN) test using the Nose strain and virus isolation. Eighteen PI cattle were detected from 5 herds. On the phylogenetic tree based on the nucleotide sequences of the 5' untranslated region, the isolates from the PI cattle were classified into genotypes-1a or -1b. Of 3 unvaccinated calves aged 6 to 12 months selected from each herd, the probabilities of obtaining 2 or more non-PI cattle with SN antibody titers of 64 or more (P(SN)), one or more PI cattle (P(VI)), and either of the conditions (P(Total)) were calculated using the hypergeometric probability model. P(Total) for the 5 herds with PI cattle was 1.000. P(SN) for 3 herds with many PI cattle within the selected age group was as low as 0.500 or less, and P(VI) was as high as 0.886 or more. P(SN) in the 2 other herds with few PI cattle was 1.000, and P(VI) was as low as 0.375 or less. P(Total) in 13 of 15 herds without PI cattle was 0.000, and was 0.714 or 0.774 for the 2 other herds. These results suggest that herds with PI cattle can be predicted with high accuracy when both SN test and virus isolation are performed on only 3 unvaccinated calves aged 6 to 12 months selected from a herd.     

Benzodiazepines inhibit the acetylcholine receptor-operated potassium current (IK.ACh) by different mechanisms in guinea-pig atrial myocytes

The anticholinergic effects of 7 benzodiazepines, bromazepam, camazepam, chlordiazepoxide, diazepam, lorazepam, medazepam and triazolam, were compared by examining their inhibitory effects on the acetylcholine receptor-operated potassium current (I(K).(ACh)) in guinea-pig atrial myocytes. All of these benzodiazepines (0.3-300 μM) inhibited carbachol (1 μM)-induced I(K).(ACh) in a concentration-dependent manner. The ascending order of IC(50) values for carbachol-induced I(K).(ACh) was as follows; medazepam, diazepam, camazepam, triazolam, bromazepam, lorazepam and chlordiazepoxide (>300 μM). The compounds, except for bromazepam, also inhibited I(K).(ACh) activated by an intracellular loading of 100 μM guanosine 5'-[γ-thio]triphosphate (GTPγS) in a concentration-dependent manner. The ascending order of IC(50) values for GTPγS-activated I(K).(ACh) was as follows; medazepam, diazepam, camazepam, lorazepam, triazolam chlordiazepoxide (>300 μM) and bromazepam (>300 μM). To clarify the molecular mechanism of the inhibition, IC(50) ratio, the ratio of IC(50) for GTPγS-activated I(K).(ACh) to carbachol-induced I(K).(ACh), was calculated. The IC(50) ratio for camazepam, diazepam, lorazepam, medazepam and triazolam was close to unity, while it for chlordiazepoxide could not be calculated. These compounds would act on the GTP binding protein and/or potassium channel to achieve the anticholinergic effects in atrial myocytes. In contrast, since the IC(50) ratio for bromazepam is presumably much higher than unity judging from the IC(50) values (104.0 ± 30.0 μM for carbachol-induced I(K).(ACh) and >300 μM for GTPγS-activated I(K).(ACh), it would act on the muscarinic receptor. In summary, benzodiazepines had the anticholinergic effects on atrial myocytes through inhibiting I(K).(ACh) by different molecular mechanisms.     

Histone H4 gene expression and morphological changes on shoot apices of strawberry (Fragaria × ananassa Duch.) during floral induction

To investigate flower induction in June-bearing strawberry plants, morphological changes in shoot apices and Histone H4 expression in the central zone during flower initiation were observed. Strawberry plants were placed under flower inducible, short-day conditions (23 °C/17 °C, 10 h day length) for differing number of days (8, 16, 20, 24 or 32 days) and then these plants were transferred to non-inducible, long-day conditions (25 °C/20 °C, 14 h day length). The shoot apices of plants placed under short-day conditions for 8 days were flat, similar to shoot apices of plants in the vegetative phase of development, and Histone H4 was not expressed in the central zone during the experimental period. On the other hand, the shoot apices of plants placed under short-day conditions for 16 days remained flat, similar to shoot apices of plants placed under short-day conditions for 8 days, but Histone H4 was expressed in the central zone at the end of the short-day treatment. Morphological changes in the shoot apices of these plants were observed 8 days after the change in day-length. These plants developed differentiated flower organs after they were grown for another 30 days under long-day conditions. These results indicate that changes in the expression pattern of the Histone H4 gene occur before morphological changes during flower induction and that the expression of the gene in the central zone can be used as one of the indicators of the flowering process in strawberries.     

Wind tunnel study on aerodynamic characteristics of shrubby specimens of three tree species

With the popularization of green roofing systems, their wind resistant performance is becoming more and more important especially in typhoon areas. A prerequisite study was carried out to determine the aerodynamic characteristics of suitable trees to provide basic scientific data. Shrubby specimens of three tree species appropriate for intensive green roofs with different aerodynamic forms were tested through a boundary layer wind tunnel experiment, including one deciduous tree, one coniferous tree and one broadleaf evergreen tree. Drags and overturning moments under different wind speeds were measured; wind-speed-specific frontal areas and tip displacements were recorded. After initial tests, trees were pruned to investigate the effect of crown porosity, and the effects of view angle and turbulence intensity were also considered. The results showed that even considering frontal area reduction due to increasing wind speeds, drag coefficients decreased with increase in wind speed for deciduous and coniferous trees. Drag coefficient characteristics for different trees agreed well with those obtained from previous researches. The effect of crown porosity varied among tree species, but view angle and turbulence intensity did not significantly affect it.     

A piglet with concurrent polioencephalomyelitis due to porcine teschovirus and postweaning multisystemic wasting syndrome

A piglet developed respiratory distress followed by difficulty in standing and unsteady gait. The lesions were characterized by polioencephalomyelitis with the predominant distribution in the brain stem, as well as lymphocyte depletion and histiocyte infiltration with cytoplasmic inclusion bodies in the lymphoid tissues throughout the body and interstitial pneumonia. Porcine teschovirus (PTV) antigens were found in the former lesions and porcine circovirus 2 (PCV2) in the latter two lesions. PTV genes were detected from the diencephalon. The results suggest that the piglet was concurrently affected with polioencephalomyelitis due to PTV and postweaning multisystemic wasting syndrome (PMWS) associated with PCV2. They also suggest that the immunosuppressive condition developing in PMWS may have facilitated the infection of the brain with PTV.     

Spatiotemporal catch distribution of age-0 Pacific bluefin tuna Thunnus orientalis caught by the Japanese troll fishery in relation to surface sea temperature and seasonal migration

This study used a delta-lognormal model to analyze monthly catches of age-0 Pacific bluefin tuna by the troll fishery. The model included fixed effects of month, area, and month–area interaction, and random effects of port, year and port–year interaction. The catch patterns by month and area predicted by the statistical model (standardized catch) revealed that main fishing grounds along the Tsushima Warm Current generally shifted from north to south as the season turned from autumn to winter. In contrast, the standardized catch along the Kuroshio Current did not show such clear spatiotemporal patterns. The standardized catch along the Tsushima Warm Current is significantly associated with average monthly sea surface temperatures in the fishing grounds and consistent with migration routes revealed by tagging experiments in previous studies. These associations indicate the spatiotemporal catch pattern in the Tsushima Warm Current region partly reflects seasonal migration. Knowledge of the possible associations among fish migration, environmental factors and spatiotemporal distribution of the catch will contribute to future management of this species.