Effects of sterilization on the chemical forms of heavy metals in soils

We used sequential extraction to investigate changes in the amounts of six chemical forms of manganese, cobalt and cadmium in soil samples after chloroform fumigation. The six forms were designated as follows: exchangeable, dilute-acid-soluble, manganese-oxide-occluded, organically bound, iron-oxide-occluded and residual. For all three metals, the decreases in the amounts of manganese-oxide-occluded forms were equivalent to the sum of the increases in the amounts of exchangeable and dilute-acid-soluble forms. The amounts of the other three forms did not change significantly after fumigation. These results indicate that some of the cobalt and cadmium in the manganese oxides was converted into exchangeable and dilute-acid-soluble forms, which suggests that soil sterilization may increase the availability of these heavy metals to plants.     

Development of AFLP-derived SCAR markers associated with resistance to two races of southern root-knot nematode in sweetpotato

The southern root-knot nematode (SRKN) Meloidogyne incognita severely damages yield and quality in sweetpotato production, and host plant resistance is one of the primary options for SRKN control. Segregation of F₁ progeny resistant and susceptible to the SP1 and SP2 races of SRKN suggested that the race-specific resistance of the sweetpotato cultivar ??Hi-Starch?? is mostly controlled by single genes and that the genes for resistance against each race are closely located. Bulked segregant analysis and subsequent analysis of 86 F₁ progeny plants identified nine amplified fragment-length polymorphism markers associated with SRKN resistance and a single linkage map consisting of seven of these markers. Quantitative trait locus (QTL) analysis using the segregating resistance data of the F₁ progeny allowed mapping of both a locus with a large effect on resistance to the SRKN race SP1 and another affecting resistance to SP2 to the region around E33M53_090 that was designated as qRmi(t). Two AFLP markers in the vicinity of qRmi(t), E33M53_090 and E41M32_206, were converted to locus-specific sequence-characterized amplified region markers based on their internal and adjacent DNA sequences. These markers might be useful for marker-assisted selection of SRKN resistance in sweetpotato breeding and as a first step to map-based cloning of the responsible QTL(s).     

Factors associated with antimicrobial-resistant Escherichia coli in zoo animals

Factors associated with the carriage of antimicrobial-resistant Escherichia coli isolates were analysed among zoo animals. An association was observed between selection of amoxicillin as the first-line therapy and a significantly higher percentage of resistance to ampicillin (54.5%) from 11 animals treated with antimicrobials, compared with isolates from 32 untreated animals (9.4%). In addition, the percentage resistance to kanamycin (36.4%), gentamicin (27.3%), trimethoprim (27.3%) and tetracycline (63.6%) from 11 treated animals was significantly higher than those from 32 untreated animals (3.1%, 3.1%, 3.1% and 25%, respectively), although these antimicrobials were rarely used. All kanamycin-, gentamicin- and trimethoprim-resistant isolates and more than half of the tetracycline-resistant isolates from treated animals were also resistant to ampicillin. Co-resistance to other antimicrobials with ampicillin was suggested to contribute to an increasing of resistance towards antimicrobials that were rarely administered. The present investigation revealed an association of antimicrobial treatment with the spread of antimicrobial-resistant bacteria among zoo animals.     

Development of an air-injection press for preventing blowout of particleboard IV: effects of air-injection conditions on board performance and formaldehyde emission

An air-injection press, which has holes punched in the heating plates, injects high-pressure air through the holes of one plate into particleboard and discharges the air through the other plate during press heating. The press can manufacture particleboard from high-moisture particles by controlling blowout of the boards. In this study, the optimum diameter and spacing of the air-injection holes and the effects of pre- and post-pressing were investigated. An optimum hole diameter was not found for the modulus of rupture and thickness swelling for a spacing of either 25 or 50 mm. In terms of internal bond strength, the optimum diameter of the holes arranged at a spacing of 25 mm was 1 mm, but the internal bond strength was not changed by the diameter of holes spaced 50 mm apart. Air injection under all hole conditions reduced the formaldehyde emission from the board. Pre-pressing was tested for further increase in the modulus of rupture and internal bond strength, but was found to have no effect. More efficient use of the air-injection press was achieved by injecting air from the early stages of pressing.     

Performance of particleboard manufactured using air-injection press I: effects of air-injection press on preventing blowout of board manufactured from low-moisture particles

An air-injection press (AIP) was developed to prevent accidental blowouts of boards during production. In this study, the effects of the AIP on preventing blowouts were investigated by artificially creating a blowout-prone condition, and the press was shown to be effective in preventing blowouts. The modulus of rupture of the boards was almost constant irrespective of pressing time. Longer pressing time resulted in higher internal bond strength when pressed at 170 °C. The thickness swelling of the boards pressed at 170 or 190 °C was almost uniform irrespective of pressing time, and the manufactured boards showed performance similar to those manufactured with an ordinary press. The AIP prevented blowouts sufficiently even when the pressure of the injected air was reduced, and this reduction did not adversely decrease the performance of the boards. Air injection reduced formaldehyde emissions from the board.     

Effects of rice feeding and carnitine addition on growth performance and mRNA expression of protein metabolism‐related genes in broiler grower chicks

This study was carried out to evaluate the nutritional effects of rice feeding and carnitine addition to a diet for broiler chicks. Thirty‐six male 10‐day‐old broiler chicks were assigned to one of the following four treatment groups: corn‐based diet (corn group), rice‐based diet (rice group), and each diet with added carnitine (100 ppm). The experimental period was 2 weeks. Rice feeding resulted in significantly higher growth performance (body weight gain and feed efficiency) compared to corn feeding. Carnitine addition also resulted in higher growth performance. Breast muscle and thigh muscle weight (g) were significantly higher in broiler chicks fed rice and those fed diets with added carnitine. Liver mRNA expression of IGF‐I was significantly higher in broiler chicks fed rice compared to those fed corn. There was no significant difference in mRNA expression of muscle atrogin‐1 or liver CPT‐I between broiler chicks fed rice and those fed corn, not between broilers chicks fed diets containing carnitine or not. Overall, these results show that rice feeding and carnitine addition improve the growth performance of broiler chicks by increasing mRNA expression of liver IGF‐I. In addition, carnitine action is not affected by different cereals (corn and rice).     

Bacillus cereus from the environment is genetically related to the highly pathogenic B. cereus in Zambia

To follow-up anthrax in Zambia since the outbreak in 2011, we have collected samples from the environment and the carcasses of anthrax-suspected animals, and have tried to isolate Bacillus anthracis. In the process of identification of B. anthracis, we collected two isolates, of which colonies were similar to B. anthracis; however, from the results of identification using the molecular-based methods, two isolates were genetically related to the highly pathogenic B. cereus, of which clinical manifestation is severe and fatal (e.g., pneumonia). In this study, we showed the existence of bacteria suspected to be highly pathogenic B. cereus in Zambia, indicating the possibility of an outbreak caused by highly pathogenic B. cereus.     

Forestomach developmental failure in an 11-month-old Japanese Black steer with severely retarded growth and chronic ruminal tympany

This study reports findings from the pathological examination of the forestomach of an 11-month-old Japanese Black steer with severely retarded growth (41% of expected weight) and chronic ruminal tympany. The ruminal papillae were weakly formed (0.3–0.5 cm long) and unevenly distributed. The cellulae and cristae reticuli were underdeveloped; the cristae were 0.4–0.7 cm in height and milky white. The keratinized layer in the stratified squamous epithelium was thickened. Ruminal pH was 5.25, and ruminal volatile fatty acid concentration was 11.7 mM. The steer’s severely retarded growth was considered to be caused by malnutrition due to developmental and functional failure of the forestomach.     

Morphological reproductive characteristics of testes and fertilization capacity of cryopreserved sperm after the Fukushima accident in raccoon (Procyon lotor)

Since the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, we have established an archive system of livestock and wild animals from the surrounding ex-evacuation zone. Wildlife within the alert zone have been exposed to low-dose-rate (LDR) radiation for a long continuous time. In this study, we analysed the morphological characteristics of the testes and in vitro fertilization (IVF) capacity of cryopreserved sperm of racoons from the ex-evacuation zone of the FDNPP accident. The radioactivity of caesium-137 (¹³⁷Cs) was measured by gamma-ray spectrometry, and the measured radioactivity concentration was 300–6,630 Bq/kg in the Fukushima raccoons. Notably, normal spermatogenesis was observed in the seminiferous tubules of the testes, with the germinal epithelium composed of a spermatogenic cell lineage with no evident ultrastructural alterations; freeze-thawing sperm penetration ability was confirmed using the interspecific zona pellucida-free mouse oocytes IVF assays. This study revealed that the chronic and LDR radiation exposure associated with the FDNPP accident had no adverse effect on the reproductive characteristics and functions of male raccoons.