A preliminary experiment regarding the natural induction of gonadal development in female Japanese eels without hormone treatment

To test whether gonadal development of female eels could be promoted without any exogenous hormone treatments, we observed the effect of water temperature manipulation. After 3–5 months of water temperature treatments, three silver eels showed higher gonadosomatic indices (GSI). In particular, one eel in the 5–15°C fluctuating temperature treatment group (5°C daytime and 15°C night‐time) had the highest GSI of 8.5 with secondary yolk globule stage oocytes of large diameter (OD; 412 μm) after 3 months, which indicated definite gonadal development compared with those in the initial states (mean GSI, 2.4; OD, 226.7 μm). The 5–15°C fluctuating temperature and constant 5°C groups had low oocyte breakdown (atretic) rates. Because daily temperature fluctuations and cold daytime water are experienced by vertically migrating silver eels in the ocean, these temperature conditions may be key maturation process components that could be useful for hormone‐free artificial maturation.     

cDNA cloning and primary structure comparison of tauropine dehydrogenase and β-alanopine dehydrogenase from the limpet <Emphasis Type="Italic">Cellana grata</Emphasis>

The primary structures of β-alanopine dehydrogenase (β-AlDH) and tauropine dehydrogenase (TaDH) from the limpet Cellana grata were determined by amino acid sequence analysis and complementary DNA (cDNA) cloning. β-AlDH and TaDH cDNAs comprised 1,479 nucleotides and 1,444 nucleotides, respectively, and both included an open reading frame of 1,206 nucleotides corresponding to 402 amino acids. The enzymes showed very high homology, with 96% amino acid identity. These enzymes were homologous to other marine invertebrate opine dehydrogenases (OpDHs), except TaDH of the marine sponge Halichondria japonica. The highest homologies were to alanopine dehydrogenase from Fusitriton oregonensis, being 57% for both enzymes. A phylogenetic tree constructed on the basis of marine invertebrate OpDHs and developed using a sequence distance method and neighbor-joining algorithm showed a tendency for the classification of animals from taxonomically derived evolutionary trees. Additionally, Cellana grata OpDHs belong to the same group as the Gastropoda OpDHs. This represents the first report concerning the primary structure of marine invertebrate β-AlDH, and primary structure comparisons of clearly different enzymes from the same species.     

Objective evaluation of whiteness of cooked rice and rice cakes using a portable spectrophotometer

The whiteness of cooked rice and rice cakes was evaluated using a portable spectrophotometer with a whiteness index (WI). Also, by using boiled rice for measurement of Mido values by Mido Meter, it was possible to infer the whiteness of cooked rice without rice cooking. In the analysis of varietal differences of cooked rice, ‘Tsuyahime’, ‘Koshihikari’ and ‘Koshinokaori’ showed high whiteness, while ‘Satonoyuki’ had inferior whiteness. The whiteness of rice cakes made from ‘Koyukimochi’ and ‘Dewanomochi’ was higher than the whiteness of those made from ‘Himenomochi’ and ‘Koganemochi’. While there was a significant correlation (r = 0.84) between WI values and whiteness scores of cooked rice by the sensory test, no correlation was detected between the whiteness scores and Mido values, indicating that the values obtained by a spectrophotometer differ from those obtained by a Mido Meter. Thus, a spectrophotometer may be a novel device for measurement of rice eating quality.     

Prevalence of porcine reproductive and respiratory syndrome virus and porcine circovirus type 2 in piglets after weaning on a commercial pig farm in Japan

To investigate the transition in concentration of porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) and antibody for these viruses in serum, serum samples were collected from 29 pigs on weaning day and at 7, 14, 21, 28, 53, 84, and 120 days after weaning. The concentration of circulated PRRSV and PCV2 in serum was measured by real-time RT-PCR and real-time PCR, respectively. The specific antibody for PRRSV and PCV2 was measured using ELISA. PRRSV was not detected on 0 days post-weaning (dpw). The specific antibody for PRRSV began to increase as the concentration of PRRSV in serum increased, and the level of PRRSV then tended to decrease. PCV2 was detected in 12 of 28 pigs on 0 dpw. The concentration of PCV2 and the specific antibody for PCV2 showed a similar tendency to those of PRRSV. The correlation analysis suggests that a decline in the daily weight gain coincided with an increase in the PRRSV concentration. Pigs with a higher antibody titer against PRRSV or PCV2 on 0 dpw showed the lower level of PRRSV or PCV2, respectively.     

Characterization of mucin gene expression and goblet cell proportion in inflammatory colorectal polyps in miniature dachshunds

Hyperplastic goblet cells and abundant mucus are significant characteristics of inflammatory colorectal polyps (ICRPs) in miniature dachshunds. In this study, selected mucin gene expressions and goblet cell proportions were evaluated in miniature dachshunds with ICRPs and in healthy dogs. Mucin 2 (MUC2) gene expression was not significantly different among the groups, whereas mucin 5AC (MUC5AC) gene expression was significantly higher in the polypoid lesions than in healthy colonic mucosa. Although the percentage of goblet cells in the upper crypt regions did not significantly differ between the groups, that in the lower crypt regions was significantly decreased in polypoid lesions. In conclusion, increased MUC5AC gene expression and goblet cell proportion changes may be associated with the pathogenesis of ICRPs.     

Population structure of pigs determined by single nucleotide polymorphisms observed in assembled expressed sequence tags

We have collected more than 190 000 porcine expressed sequence tags (ESTs) from full‐length complementary DNA (cDNA) libraries and identified more than 2800 single nucleotide polymorphisms (SNPs). In this study, we tentatively chose 222 SNPs observed in assembled ESTs to study pigs of different breeds; 104 were selected by comparing the cDNA sequences of a Meishan pig and samples of three‐way cross pigs (Landrace, Large White, and Duroc: LWD), and 118 were selected from LWD samples. To evaluate the genetic variation between the chosen SNPs from pig breeds, we determined the genotypes for 192 pig samples (11 pig groups) from our DNA reference panel with matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry. Of the 222 reference SNPs, 186 were successfully genotyped. A neighbor‐joining tree showed that the pig groups were classified into two large clusters, namely, Euro‐American and East Asian pig populations. F‐statistics and the analysis of molecular variance of Euro‐American pig groups revealed that approximately 25% of the genetic variations occurred because of intergroup differences. As the F_IS values were less than the F_ST values_, the clustering, based on the Bayesian inference, implied that there was strong genetic differentiation among pig groups and less divergence within the groups in our samples.     

Sulfur Isotope Variations in Atmospheric Sulfur Oxides, Particulate Matter and Deposits Collected at Kyushu Island, Japan

Atmospheric sulfur oxides, particulate matter and deposits (wet and dry deposits) were collected from July 1998 to June 1999 at Kyushu Island, Japan. The isotopic composition of sulfur (δ³⁴S) was measured to identify the source of sulfur in the samples. The monthly δ³⁴S values were always low in the order of the sulfur oxides, sulfate in particulate matter and deposits. The δ³⁴S values of the sulfur oxides ranged from ?2.7 ‰ to ?0.4 ‰ and were close to those of fossil fuels used in Japan. The δ³⁴S values of sulfate in the particulate matter and deposits correlated with seasalt contribution, so that the δ³⁴Snss value was calculated for non-seasalt sulfate. The δ³⁴Snss values of sulfate in the particulate matter and deposits trended higher in winter than summer, suggesting the possibility of isotopic fractionation during chemical transformation (SO₂ to SO₄ ^2?) and of contribution of sulfate derived from sulfur sources with higher δ³⁴S values.     

Carbonization of bamboo and consecutive low temperature air activation

Raw moso bamboo (Phyllostachys pubescens) was examined to optimize the carbonization and the consecutive air activation procedure. Influence of sample size, nitrogen flow rate, heating rate and final temperature on the carbon yield and the pore structure was investigated for the raw bamboo. The short length cutting along bamboo trunk and the increase in heating rate to 40°C/min and nitrogen flow rate up to 500 ml/min was found to be advantageous for the carbonization of raw bamboo at 500°C, resulting in a surface area of 230 m²/g with a bamboo char yield of 25% on dry base. In the next step, effects of air treatment temperature, ash content and its composition on the pore development were studied for the prepared bamboo char in comparison with coconut shell char. Additional increase in surface area by 200 m²/g with 97% yield could be achieved conducting the 2-hour air treatment at 280°C for the bamboo char, whereas only a 100 m²/g rise in surface area was attained for the coconut shell char, partly due to the difference in K₂CO₃ content in the char.     

Anti‐tumour activity of oncolytic reovirus against canine histiocytic sarcoma cells

Canine histiocytic sarcoma is an aggressive, fatal neoplastic disease with a poor prognosis. Lomustine is generally accepted as the first‐line systemic therapy, although this compound does not provide complete regression. Therefore, research into a novel approach against canine histiocytic sarcoma is needed. However, anti‐tumour effects of oncolytic therapy using reovirus against histiocytic sarcoma are unknown. Here, we showed that reovirus has oncolytic activity in canine histiocytic sarcoma cell lines in vitro and in vivo. We found that reovirus can replicate and induce caspase‐dependent apoptosis in canine histiocytic sarcoma cell lines. A single intra‐tumoural injection of reovirus completely suppressed the growth of subcutaneously grafted tumours in NOD/SCID mice. Additionally, we demonstrated that susceptibility to reovirus‐induced cell death was attributable to the extent of expression of type I interferons induced by reovirus infection in vitro. In conclusion, oncolytic reovirus appears to be an effective treatment option for histiocytic sarcoma, and therefore warrants further investigation in early clinical trials.