Application of supercooling to long-term storage of fish meat

Fish meat was brought to a supercooled state through slow cooling, and changes in the texture, histology, and protein composition of the meat were investigated. The groups whose storage temperature were lowered by 1.0°C per day (the 1.0°C group) and 0.5°C per day (the 0.5°C group) began to freeze in the vicinity of −3.5 and −5.0°C, respectively. The freezing point depended on the fish species; the lowest freezing point was −8.5°C, for the red sea bream in the 1.0°C group. The breaking strength tended to decrease more slowly in the 1.0°C group, but the collagen fibers collapsed more rapidly in the 1.0°C group. In SDS electrophoresis, a slight change in the banding patterns was observed, but the relationship between this observation and changes in histology and physical properties was unclear. This study shows that it is possible to produce a supercooled state in fish meat, and demonstrates that supercooling is a potential new storage method that lowers the temperature without generating ice crystals.     

基于巴西橡胶树的天然橡胶生产

天然橡胶是植物所产生的最为重要的多聚物之一,是一种重要的战略原料,以天然橡胶为原料的工业制品多达40000以上。由于天然橡胶特殊的分子构造、巨大的分子量,以及含有来自胶乳的少量其它组分,使得该聚合物表现出极其优越的综合性能。在全世界为数2500种以上的产胶植物中,巴西橡胶树Hevea brasiliensis Muell．Arg．）是商品天然橡胶的唯一来源。本文简要介绍天然橡胶最新的生产及消费动态,同时对橡胶遗传育种及可替代橡胶资源的研究现状作一综合评述。     

Naphthalene derivatives from Diospyros kaki

A detailed chemical investigation of the extractives of the blackened heartwood of Diospyros kaki was carried out to understand their chemical characteristics and to obtain chemotaxonomic information. Three novel naphthalene derivatives were isolated, i.e., 4-hydroxy-5,6-dimethoxy-2-naphthaldehyde (1), 5,6,8-trimethoxy-3-methyl-1-naphthol (2), and 4,8-dihydroxy-5-methoxy-2-naphthaldehyde (3), in addition to two previously reported 2-naphthaldehydes: 4-hydroxy-5,8-dimethoxy-2-naphthaldehyde (4) and 4-hydroxy-5-methoxy-2-naphthaldehyde (5) Their structures were identified by 1D and 2D nuclear magnetic resonance spectroscopy, as well as by high-resolution mass spectrometry.     

Induction of apoptotic lesions in liver and lymphoid tissues and modulation of cytokine mRNA expression by acute exposure to deoxynivalenol in piglets

Six 1-month-old piglets were intravenously injected with deoxynivalenol (DON) at the concentration of 1 mg/kg body weight, with three pigs each necropsied at 6 and 24 h post-injection (PI) for investigation of hepatotoxicity and immunotoxicity with special attention to apoptotic changes and cytokine mRNA expression. Histopathological examination of the DON-injected pigs revealed systemic apoptosis of lymphocytes in lymphoid tissues and hepatocytes. Apoptosis of lymphocytes and hepatocytes was confirmed by the TdT-mediated dUTP-biotin nick end-labeling (TUNEL) method and immunohistochemical staining against single-stranded DNA and cleaved caspase-3. The number of TUNEL-positive cells in the thymus and Peyer''s patches of the ileum was increased at 24 h PI compared to 6 h PI, but the peak was at 6 h PI in the liver. The mRNA expression of interleukin (IL)-1β, IL-6, IL-18, and tumor necrosis factor (TNF)-α in the spleen, thymus and mesenteric lymph nodes were determined by semi-quantitative RT-PCR, and elevated expression of IL-1β mRNA at 6 h PI and a decrease of IL-18 mRNA at 24 h PI were observed in the spleen. IL-1β and IL-6 mRNA expressions increased significantly at 6 h PI in the thymus, but TNF-α decreased at 6 h PI in the mesenteric lymph nodes. These results show the apoptosis of hepatocytes suggesting the hepatotoxic potential of DON, in addition to an immunotoxic effect on the modulation of proinflammatory cytokine genes in lymphoid organs with extensive apoptosis of lymphocytes induced by acute exposure to DON in pigs.     

Variation in the effects of ethephon on flowering and extension growth in chrysanthemum as a function of temperature,season, and genetics

Summary

Ethephon (2-chloroethylphosphonic acid), an ethylene-releasing agent, is used in the production of Summer-to-Autumn-flowering chrysanthemums (Chrysanthemum morifolium Ramat.) to avoid early budding under long-day conditions. This study was carried out to show the variation in response to ethephon due to temperature, season, and cultivar. The seasonality of growth and flowering capacities, growing temperatures, and the genetic background of chrysanthemum make the effects of ethephon unstable and variable. The most important factor modifying the effect was the response to temperature, which showed seasonal variation. Ethephon briefly suppressed extension growth and flowering after chilling and at high growing temperatures. On the other hand, it induced dormancy and rosette formation, and suppressed flowering after Summer, and at lower temperatures. This suggests that ethylene is involved in the induction of dormancy.     

Contribution of charcoal to short-term nutrient dynamics after surface fire in the humus layer of a dwarf bamboo-dominated forest

Ecological function of charcoal has been mainly investigated by adding charcoal to soil, which is not fully adequate to understand in situ the role in fire-prone forest ecosystem. To determine in situ effects of charcoal on ecosystem functions, such as nutrient availability, we conducted an experimental burning in a Japanese white birch forest with dense coverage of dwarf bamboo in the understory with or without removal of charcoal. Ammonium-N in the remaining humus layer increased immediately after the burning, but decreased to the level of unburnt plots within 1?month of the burning. Removal of charcoal had no significant effect on the NH₄ ⁺-N dynamics. Although burning did not affect NO₃ ^?-N dynamics during the sampling period, charcoal removal led to a slight increase in NO₃ ^?-N. The available P increased immediately after the burning, but then fell at 1?month after burning. Charcoal inhibited the available P depletion and prolonged the high availability of P. Greater availability of P might be due to the adsorption of phosphate in charcoal pores. Exchangeable Ca and Mg increased gradually; charcoal appeared to extend the period of higher concentration of exchangeable Ca and Mg. Charcoal deriving from fire is a key factor in influencing available nutrient in the humus layer of post-fire forests.     

Proventricular dilatation disease associated with avian bornavirus infection in a Citron-crested Cockatoo that was born and hand-reared in Japan

A 5-month-old female Citron-crested Cockatoo (Cacatua sulphurea citrinocristata) that was born and hand-reared in Japan died with suspected proventricular dilatation disease (PDD). Macroscopic and microscopic examinations of the bird revealed characteristic features of PDD, i.e., distention of the proventriculus and infiltration of lymphocytes and plasma cells in ganglia of various organs and in central and peripheral nerves. A linkage of this PDD case to infection with avian bornavirus (ABV) was documented by RT-PCR amplification of the virus genomes from the affected bird. Phylogenetic analysis revealed that the ABV identified in this study clustered into the genotype 2, which is one of the dominant ABV genotypes worldwide. To the best of our knowledge, this is the first report of a natural case of PDD associated with ABV infection in Japan.     

Cryopreservation of canine spermatozoa using a skim milk-based extender and a short equilibration time

Although useful spermatozoa cryopreservation techniques have been established, long-term equilibration seems to be required before freezing the spermatozoa of many species, including dogs. The fertility of cryopreserved dog spermatozoa from five males for a reduced equilibration period (0, 30, 60, 120 and 180 min) in a skim milk (SM)-based extender containing raffinose was evaluated in the present study. When the sperm was diluted with the extender at room temperature (RT) and cryopreserved without equilibration, the proportion of total motile spermatozoa (TMS) after thawing was lower (27%) than when the sperm was equilibrated for 30 min (33%), 60 min (32%), 120 min (44%; p < .05) or 180 min (29%). The proportion of TMS increased as the equilibration time increased and peaked at 120 min. Acrosome integrity was significantly lower in the cryopreserved spermatozoa that had not undergone the initial equilibration than in the equilibrated spermatozoa (p < .05). The normal rate of acrosomes increased with the extension of the first equilibration and peaked at 120 min. When frozen–thawed spermatozoa that had been diluted at RT and subjected to an initial equilibration lasting 60 or 180 min were transcervically inseminated into recipients, there were no differences in the delivery rate, litter size or breeding efficiency. In the cryopreservation of canine spermatozoa using a SM-based extender, even if the initial equilibration time was shortened to 60 min, the results were comparable to those obtained when the conventional method (with an initial equilibration time of 180 min) was used.     

Foliar absorption of nutrients: III

In the last report¹⁾ the purity of radioactive potassium. which had been produced by ⁴¹K (d, p) ⁴²K nuclear reaction and separated from, radioactive anions by the use of ion exchange resin, was tested by means of its decay curve. By this test, it is difficult to distinguish ⁴²K from ²⁴Na contamination, because the half life of radioactive sodium (²⁴Na) is 15.06 hours²⁾ and it is very similar to that of radioactive potassium (⁴²K) which is 12.4 hours. When the nuclear reaction ²³Na (d, p) ²⁴Na occurs, the cross section of this reaction for deuterons is about 100 times that of potassium nuclear reaction. In this case the purity of radioactive potassium (⁴²K) could be confirmed by its Gamma-ray spectrum. According to the result, radioactive potassium of high purity was obtained. Potassium phosphate which was double-labeled by this radioactive potassium and imported radioactive phosphorus (³²P) was applied to leaves or roots of bean plants.     

Foliar absorption of nutrients IV

Active surface agents are often added to spray solutions to facilitate the uniform wetting and coveringg of the leaf surfaces^1),2). Some have reported that the addition of active surface agents increased the absorption of nutrients, but others have reported different results.