Effects of manufacturing factors on the viscosity of a polysaccharide solution extracted from Gagome Kjellmaniella crassifolia

A highly viscous polysaccharide solution was extracted from Gagome Kjellmaniella crassifolia in 20°C water. The eluted sugar concentration was 0.16%, and the extracted carbohydrates consisted of fucoidan, laminaran, and alginate at an approximately ratio of 8.2:0.8:1.0. An increase in the extraction temperature resulted in a less viscous solution, even though the amount of eluted sugar was higher than that obtained at a lower temperature. The most viscous extraction solution was obtained at a neutral pH, with a more acidic or alkaline extraction solution being a less viscous. When the highly viscous polysaccharide solution was heated, the viscosity decreased markedly with increasing temperature. The viscosity of the polysaccharide solution increased after dialysis against water and decreased with the addition of either KCl or NaCl. However, the viscosity was recovered to previous levels by following re-dialysis against water. The removal of divalent cations by EDTA and the re-addition using CaCl₂ or MgCl₂ also caused reversible changes to the viscosity. These characterizations will be useful for widespread applications of viscous K. crassifolia polysaccharides.     

Analysis of Potassium Uptake by Rice Roots Treated with Aluminum Using a Positron Emitting Nuclide, 38K

We investigate the effect of Al on K⁺ uptake by rice roots. Potassium-38 (³⁸K), a positron emitting nuclide (the half-life: 7.61 min), was used to trace K⁺ behavior. When a rice root was treated with 10μM Al for 24 h, the uptake of ³⁸K in the root was increased in the range of 1 to 2 cm from the root tip compared with that of the control sample. Because the root continued to grow without showing any damage of plasma membrane during the Al treatment, it was suggested that the ³⁸K uptake was not occurred through diffusion into the cells. The uptake of ³⁸K in both treatments, with/without Al, was decreased by VO₄^3- (inhibitor of H⁺-ATPase on plasma membrane) and DNP (H⁺ ionophore) treatment, which suggested that the K⁺ uptake was performed through an active transport, such as H⁺:K⁺ transport or H⁺ gradient promoted by an Al treatment.     

Efficacy of a novel in ovo-attenuated live vaccine and recombinant vaccine against a very virulent infectious bursal disease virus in chickens

Infectious bursal disease (IBD) causes severe economic damage to the poultry industry worldwide. To prevent IBD virus (IBDV) infection, live virus vaccines have been widely used in chickens having wide-ranging levels of maternally derived antibodies. But, the risks of infection with other pathogens because of lesions related to atrophy of the bursa of Fabricius in vaccinated chickens are a concern. To resolve the problems, a recombinant turkey herpesvirus (HVT) vaccine expressing IBDV-VP2 protein (rHVT-IBD) has been developed. However, the induction of neutralizing antibodies by rHVT-IBD against a virulent IBDV might be delayed compared with that by the live IBD vaccine, leading to the high risks of IBDV infection for young chickens. To find the best selection of IBDV vaccine for the onset of immunity, we examine the protective efficacy of a novel in ovo-attenuated live IBDV (IBD-CA) vaccine and the rHVT-IBD vaccine in young chickens challenged with a very virulent IBDV (vvIBDV) strain. We show that the protective efficacy of IBD-CA vaccine was higher than that of the rHVT-IBD vaccine in 14-day-old chickens challenged with the vvIBDV strain, leading to the risk of IBDV infection for young chickens when vaccinated with rHVT-IBD. Our results suggest that farmers should select the best vaccines to maximize vaccine efficacy in consideration of the vaccine characteristics, prevalence levels of IBDV in the areas, and initial MDA levels of the chickens since the attenuated live and recombinant vaccines play a role in the different vaccine efficacies.     

Origin of a pair of red-crowned cranes (Grus japonensis) found in Sarobetsu Wetland,northwestern Hokkaido,Japan: a possible crossbreeding between the island and the mainland population

Red-crowned cranes Grus japonensis, which are an endangered species, have two separate populations, a mainland population in the Eurasian continent and an island population in eastern Hokkaido, Japan. Island cranes showed three haplotypes (Gj1, Gj2 and Gj13), whereas ten haplotypes (Gj3–Gj12) were confirmed in captive cranes and stray cranes. We found Gj5 haplotype in feathers of two cranes as well as four new haplotypes in seven wild crane feathers collected in South Korea. We also found feathers in the nest in Sarobetsu Wetland in northwestern Hokkaido. While the haplotype of female-derived feathers was Gj2, that of male-derived feathers was Gj5. The results suggest that there has been crossbreeding between cranes in the island population and cranes in the mainland population.     

Diffusion tensor imaging-based quantitative analysis of the spinal cord in Pembroke Welsh Corgis with degenerative myelopathy

Canine degenerative myelopathy (DM) is a progressive neurodegenerative disease of the spinal cord. The diagnosis is based on the observation of clinical signs, genetic testing, and exclusion of other spinal cord diseases, and a definitive diagnosis of DM can only be confirmed by postmortem histopathological findings. The aim of this study was to investigate the diagnostic ability of diffusion tensor imaging (DTI) for DM. Eight DM-affected Pembroke Welsh Corgis, thirteen dogs with thoracolumbar intervertebral disk herniation (IVDH), and six healthy control dogs were included. All dogs were scanned using a 3.0-T MRI system. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values were calculated for each intervertebral disk level slice between T8–T9 and L2–L3 intervertebral disk levels, and the entire area of the thoracolumbar spinal cord between T8–T9 and L2–L3 intervertebral disk levels (T8–L3 region). The ADC and FA values of the T8–L3 region were significantly lower in the DM group than in the IVDH group. The ADC values for the T8–L3 region had a moderate negative correlation with clinical duration (r_s= −0.723, P=0.043); however, the FA values of other intervertebral disk levels and T8–L3 region had no correlation with clinical durations. The measurement of DTI indices can be used to quantitatively assess neurodegeneration and may have diagnostic value for DM. In particular, the ADC value of the T8–L3 region may aid in making a non-invasive premortem diagnosis of DM.     

Growth of the brittle star Ophiura sarsii sarsii in Funka Bay,Hokkaido, Japan

Fisheries Science - The brittle star Ophiura sarsii with a disc diameter (DD) of less than 9 mm is an important prey item for flathead flounder Hippoglossoides dubius in Funka...     

Manageable risks and the demand for food products: the case of oyster

The risk of norovirus food poisoning from oyster consumption can be minimized by consumers, as thorough cooking can destroy norovirus. This paper uses data from 23 prefectures in Japan during 1970–2010 to examine how the demand for oysters responds to this manageable risk. We find that the incidence rate of norovirus has no effect on the price of oysters in prefectures that specialize in oysters for cooking, whereas it has significant negative impacts in prefectures that produce oysters to be eaten raw. These results indicate that consumers respond differently to manageable and non-manageable risks.     

The effect of temperature on environmental DNA degradation of Japanese eel

Fisheries Science - The environmental DNA (eDNA) technique is a convenient and powerful tool to detect rare species. Knowledge of the degradation rate of eDNA in water is important for...     

The use of machine learning to predict acute hepatopancreatic necrosis disease (AHPND) in shrimp farmed on the east coast of the Mekong Delta of Vietnam

Fisheries Science - Predicting the outbreak of disease is essential when managing shrimp farms. Acute hepatopancreatic necrosis disease (AHPND) caused by Vibrio parahaemolyticus is a serious...     

Intraspecific differentiation and geographical distribution of Wx alleles for low amylose content in endosperm of foxtail millet, Setaria italica (L.) Beauv.

To clarify the genetic mechanism which controls the variation in amylose content among nonwaxy landraces of foxtail millet, the inheritance of different starch types in endosperm was examined by I₂-KI staining. The level of starch granule bound protein in foxtail millet endosperm was also analyzed using SDS-PAGE. The segregation for starch types in F₂ and F₃ seeds determined by I₂-KI staining showed that there are three different alleles at the waxy (wx) locus. A major protein bound to starch granules was detected in nonwaxy endosperm but it was absent in most of the waxy endosperm, suggesting that the protein is the Wx gene product which is responsible for the synthesis of amylose in endosperm. The level of Wx protein proportionally corresponded to the amylose content among nonwaxy landraces. This implies that two different Wx alleles regulate quantitative levels of Wx protein. Landraces with the allele for low amylose content are from Taiwan, the Philippines, Indonesia and Thailand. This revised version was published online in July 2006 with corrections to the Cover Date.