Flesh quality of tilapia Oreochromis niloticus fed solely on raw Spirulina

ABSTRACT:   In order to simplify the food chain in a closed ecological recirculating aquaculture system, raw Spirulina platensis cultivated in 50-L photobioreactors were fed to tilapia Oreochromis niloticus as a uni-feed from the onset of exogenous feeding. The feasibility of using tilapia grown on raw Spirulina (body weight: 155.4 ± 3.9 g, standard length: 16.2 ± 0.2 cm; n  = 3) was investigated for 30 weeks for sashimi (sliced raw meat). Some of the rheological properties of the flesh were measured to clarify the obtained results of sensory evaluations of texture and fatness. The elastic modulus of flesh of the Spirulina -fed fish was significantly higher than that of the control fish (body weight: 168.9 ± 5.8 g, standard length: 17.8 ± 0.5 cm; n  = 3) that were fed commercial diets. In addition, the viscosity of the flesh of the Spirulina -fed fish was significantly lower than that of the control fish. There was no significant difference in the rupture strength between the two treatments. The rheological parameters in the muscle were found to coincide with the results of the sensory assessment. These results suggest that tilapia fed solely on raw Spirulina have a high flesh quality that is suitable for sashimi. The muscle lipid of the raw Spirulina -fed fish had lower levels of non-polar lipids such as triglycerides and partial glycerides, but higher levels of polar lipids such as phosphatidylcholine and phosphatidylethanolamine. The fatty acid profile of the raw Spirulina -fed fish muscle, especially in the polar lipid fraction, was characterized by an abundance of Σn-6 highly unsaturated fatty acids (20:3n-6, 20:4n-6, 22:4n-6, 22:5n-6).     

Inheritance and chromosomal location of the homoeologous genes affecting phenol colour reaction of kernels in durum wheat

End-use quality of wheat for noodles is influenced by polyphenol oxidase activity and its corresponding substrates. This study investigated the chromosomal location of genes that determine phenol colour reaction of kernels in tetraploid wheat using aneuploid stocks. Polyphenol oxidase activity was estimated by the colour reaction of kernels to phenol solution. It was found that the genes located on homoeologous group 2 chromosomes have an important effect on the level of phenol colour reaction of kernels. The genes (Tc1 and Tc2) responsible for high phenol colour reaction of kernels were mapped to the long arms of chromosome 2A and chromosome 2B, respectively. The map distances were estimated to be 46.8 cM for Tc1 and 40.7 cM for Tc2 from the centromere using double-diltelosomics of durum wheat.     

Formation mechanism of p-methylacetophenone from citral via a tert-alkoxy radical intermediate

The aim of this study was to clarify the formation mechanism of a potent off-odorant, p-methylacetophenone, from citral under acidic aqueous conditions. An acidic aqueous solution (pH 3.0) containing 10 mg/L of citral was stored at 40 degrees C for 2 weeks. Among the compounds detected in the stored citral solution, 4-(2-hydroxy-2-propyl)benzaldehyde was identified for the first time as a degradation product from citral. The formation of p-methylacetophenone and 4-(2-hydroxy-2-propyl)benzaldehyde behaved the same when antioxidants were added to the citral solution. In addition, both compounds were formed by the Fe(2+)-induced decomposition of 8-hydroperoxy-p-cymene, another compound identified in the stored citral solution. These results suggested that both p-methylacetophenone and 4-(2-hydroxy-2-propyl)benzaldehyde can be formed via the same radical intermediate [p-CH3C6H4C(CH3)2O*] that can be derived from the O-O bond homolysis of 8-hydroperoxy-p-cymene. On the other hand, the degradation of 8-hydroperoxy-p-cymene without Fe2+ under acidic aqueous conditions did not yield p-methylacetophenone and 4-(2-hydroxy-2-propyl)benzaldehyde, but the degradation of citral without Fe2+ did. Therefore, other than the decomposition of 8-hydroperoxy-p-cymene, a mechanism to generate the tert-alkoxy radical intermediate was proposed for the formation of p-methylacetophenone and 4-(2-hydroxy-2-propyl)benzaldehyde in the citral solution.     

Radiocesium transfer from Andosols to brown rice in the northern and northwest areas of Tochigi Prefecture,in the first 3 years following the 2011 Fukushima Daiichi nuclear power plant accident

ABSTRACT

Following the Fukushima Daiichi Nuclear Power Plant accident of 2011, the potential for radiocesium transfer from contaminated soils, such as Andosols, to agricultural crops became a significant concern. Andosols account for up to 70％ of paddy soils in the northern and northwest areas of Tochigi Prefecture, where the radiocesium concentration is 1000 Bq kg^?1 or greater in the soil of some fields. The present study was carried out in order to determine the phytoavailability of radiocesium in Andosols by comparing it with that of gray lowland soils in the first 3 years following the accident. The transfer factor (TF) tended to be higher in Andosols than in gray lowland soils, leading to higher radiocesium concentrations in brown rice grown in Andosols. The exchangeable potassium (Ex-K₂O) in Andosols was highly and negatively correlated with TF, followed by clay. The Ex-K₂O value was positively correlated with the clay/total carbon (T-C) value, suggesting that a high T–C ratio could weaken K₂O adsorption on clay mineral sites; hence, the low clay/T-C values can partially explain the relatively large TF values of Andosols. Samples with Ex-K₂O contents less than 200 mg kg^?1 and with low clay/T-C values showed striking decreases in TF values from 2011 to 2012. However, the decrease from 2012 to 2013 was quite small; radiocesium in these samples was potentially available for rice uptake for a long time, likely due to the reversible adsorption and fixation characteristics of allophane. Most gray lowland soil samples showed very low TF values over the 3 years of the study, except for those with TF values greater than 0.1 due to low Ex-K₂O and clay contents; the geometric mean (GM) value of TF was below 0.01 in 2012. The extraction of exchangeable radiocesium (Ex-Cs) with a 1 mol L^?1 ammonium acetate solution may not be an appropriate method for explaining the variability in radiocesium TF in Andosols. This is because the Ex-Cs value was significantly correlated with Ex-K₂O in Andosols, but not in gray lowland soils, indicating that Ex-K₂O explained this variability in relation to Ex-Cs.     

Evidence for ozone formation in human atherosclerotic arteries

Here, we report evidence for the production of ozone in human disease. Signature products unique to cholesterol ozonolysis are present within atherosclerotic tissue at the time of carotid endarterectomy, suggesting that ozone production occurred during lesion development. Furthermore, advanced atherosclerotic plaques generate ozone when the leukocytes within the diseased arteries are activated in vitro. The steroids produced by cholesterol ozonolysis cause effects that are thought to be critical to the pathogenesis of atherosclerosis, including cytotoxicity, lipid-loading in macrophages, and deformation of the apolipoprotein B-100 secondary structure. We propose the trivial designation "atheronals" for this previously unrecognized class of steroids.     

A 49-kilodalton phosphoprotein in the Drosophila photoreceptor is an arrestin homolog

The gene encoding the 49-kilodalton protein that undergoes light-induced phosphorylation in the Drosophila photoreceptor has been isolated and characterized. The encoded protein has 401 amino acid residues and a molecular mass of 44,972 daltons, and it shares approximately 42 percent amino acid sequence identity with arrestin (S-antigen), which has been proposed to quench the light-induced cascade of guanosine 3',5'-monophosphate hydrolysis in vertebrate photoreceptors. Unlike the 49-kilodalton protein, however, arrestin, which appears to bind to phosphorylated rhodopsin, has not itself been reported to undergo phosphorylation. In vitro, Ca2+ was the only agent found that would stimulate the phosphorylation of the 49-kilodalton protein. The phosphorylation of this arrestin-like protein in vivo may therefore be triggered by a Ca2+ signal that is likely to be regulated by light-activated phosphoinositide-specific phospholipase C.     

脱落酸(Abscisic acid, ABA)对映异构体的生物活性比较

 采用新方法精制脱落酸(ABA)异构体试样,改变以往靠光学离析法分离racemic型(SR)-(±)-ABA,提高了(S)-(+)-ABA与(R)-(-)-ABA两镜像体纯度。抑制生长试验和残留量分析结果表明:天然型(S)-(+)-ABA活性,显着高于非天然型(R)-(-)-ABA或(SR)-(±)-ABA活性。抑制莴苣种子发芽50%的活性强度(S)-(+)-ABA约是(R)-(-)-ABA的5倍,(SR)-(±)-ABA介于二者之间。抑制萝卜下胚轴生长试验,最显着有效期2～6天,(6天后差异渐小,8日甚微),生理作用期约为一周,(S)-(+)-ABA活性是(R)-(-)-ABA的3.6倍。差异原因可能是两异构体分子立体结构不同所致。     

High-density electron anions in a nanoporous single crystal: [Ca24Al28O64]4+(4e-)

We removed approximately 100% of clathrated oxygen ions from the crystallographic cages in a single crystal of 12CaO.7Al2O3, leading to the formation of high-density (approximately 2 x 10(21) cm-3) electrons highly localized in the cages. The resulting electron forms a structure that we interpret as an F+ center and migrates throughout the crystal by hopping to a neighboring cage with conductivity approximately 100 siemens per centimeter, demonstrating that the encaged electron behaves as an anion. The electron anions couple antiferromagnetically with each other, forming a diamagnetic pair or singlet bipolaron. The resulting [Ca24Al28O64]4+(4e-) may be regarded as a thermally and chemically stable single crystalline "electride."     

Production of trout offspring from triploid salmon parents

Many salmonids have become at risk of extinction. For teleosts whose eggs cannot be cryopreserved, developing techniques other than egg cryopreservation to save genetic resources is imperative. In this study, spermatogonia from rainbow trout were intraperitoneally transplanted into newly hatched sterile triploid masu salmon. Transplanted trout spermatogonia underwent spermatogenesis and oogenesis in male and female recipients, respectively. At 2 years after transplantation, triploid salmon recipients only produced trout sperm and eggs. With use of these salmon as parents, we successfully produced only donor-derived trout offspring. Thus, by transplanting cryopreserved spermatogonia into sterile xenogeneic recipients, we can generate individuals of a threatened species.     

Cytokinin oxidase regulates rice grain production

Most agriculturally important traits are regulated by genes known as quantitative trait loci (QTLs) derived from natural allelic variations. We here show that a QTL that increases grain productivity in rice, Gn1a, is a gene for cytokinin oxidase/dehydrogenase (OsCKX2), an enzyme that degrades the phytohormone cytokinin. Reduced expression of OsCKX2 causes cytokinin accumulation in inflorescence meristems and increases the number of reproductive organs, resulting in enhanced grain yield. QTL pyramiding to combine loci for grain number and plant height in the same genetic background generated lines exhibiting both beneficial traits. These results provide a strategy for tailormade crop improvement.