Correction to: Spatial and seasonal variations of radiocesium concentrations in an algae-grazing annual fish,ayu Plecoglossus altivelis collected from Fukushima Prefecture in 2014

Fisheries Science - In the original publication the caption of Fig. 6a and 6b is incorrectly published.     

Nutrients,Free Amino Acids,and Sugar Contents in Narcissus Roots Affected by N,P, K Deficiency during Winter

Non-rooted bulbs of Narcissus L. cv. “Garden Giant” were planted on October 25, 1993 and cultivated under N, P, or K deficiency or in complete medium (control). The roots emerged on November 5 and were sampled on March 7, 1994. The X-ray microanalyzer images showed the distribution of N, P, K, Ca, Mg, S, and Cl in a control root. The distribution of Cl was similar to that of K and also a similar distribution was found between Ca and S. There were significant differences in the concentration of N, P, K, Ca, Mg among treatments. Interaction among nutrient levels was observed. Control roots accumulated a large amount of nitrogen (84 mg g DW^-1) which was partitioned almost equally between the 80% ethanol soluble and insoluble fractions. N-deficient roots in the -N treatment, on the other hand, accumulated only about 12 mg g DW^-1 nitrogen, mostly in the insoluble fraction (83% of total N). Total amino acid contents responded to N, P, or K deficiency. Glutamine was a major free amino acid in control roots (17 mg N g DW^-1) and K-deficient roots (29 mg N g DW^-1), while arginine seemed to be the predominant amide in P-deficient roots. Content of total soluble sugars in the control, -P and -K treatments that was 49, 46, and 49 mg g DW^-1, respectively, was lower than in the -N treatment (137 mg g DW^-1). Mono- and disaccharides; fructose, glucose, and sucrose, were found in narcissus roots.     

Difference in system of current photosynthesized carbon distribution to carbon and nitrogen compounds between rice and soybean

¹⁴CO₂ was assimilated during 10 min in leaf of rice and soybean under 21 kPa O2 (21% O₂ treatment) and 2 kPa O₂ (2% O₂ treatment) at the vegetative growth stage and flowering stage. The ¹⁴C distribution ratio to respired CO₂ and crude chemical components (sugars, polysaccharides, amino acids, organic acids, and proteins) was determined. In this paper, since emphasis was placed on the ¹⁴C distribution mechanism to carbon compounds and nitrogen compounds, the terms carbon metabolism pool (C-pool) composed of sugars and polysaccharides, and nitrogen metabolism pool (N-pool) composed of organic acids, amino acids and proteins were used. The results obtained were as follows.

¹⁴C distribution ratio to N-pool at 0 min after ¹⁴C assimilation was higher in soybean than in rice regardless of the treatments and stages, and that at 30 min after ¹⁴C assimilation under light condition markedly decreased both in rice and soybean. Therefore, especially in soybean, a large amount of photosynthesized ¹⁴C was once distributed to the N-pool, then ¹⁴C compounds in the N-pool were reconstructed into the C-pool. During this reconstruction process, ¹⁴C compounds in the N-pool were actively respired.

¹⁴C distribution to N-pool at 0 min after ¹⁴C assimilation changed slightly or did not change by the N treatment. ¹⁴C distribution to N-pool in the - N treatment of soybean (13–29 mg N g^-1 content in leaves) was higher than that in the + N treatment of rice (31–48 mg N g^-1 content in leaves). Photosynthesized carbon distribution to N-pool in rice decreased with growth, while it remained constant in soybean. Accordingly, in soybean, photosynthesized carbon was predominantly distributed to the N-pool through photorespiration and/or Calvin cycle (supplying triose-P), which was less affected by nitrogen nutrient and aging. Thus, the mechanism of photosynthesized carbon distribution to carbon and nitrogen compounds was basically regulated by inherited characters of each plant more than by the nitrogen status of leaves.

By the 2% O₂ treatment, ¹⁴C distribution to N-pool decreased in both crops regardless of N treatment, indicating that photorespiration plays an important role in the supply of the preliminarily photosynthesized carbon compounds to N-pool. In the 2% O₂ treatment, ¹⁴C distribution to N-pool was higher in soybean than in rice, indicating that triose-P transported from chloroplast was preferentially distributed to N-pool in the case of soybean.     

Identification of long needle crystals and distribution of oxalate salts in Narcissus cv. ‘Garden Giant’

Long needle crystals abundantly present in the bulb scales and the shoot sap of Narcissus cv. ‘Garden Giant’ were identified as Ca-oxalate by ¹³C-nuclear magnetic resonance and capillary electrophoresis. The Ca-oxalate crystals were distributed in every part of the plant, including tunics, shoot, flowers, basalplate, and roots. A large proportion of water-soluble oxalate was present in the roots, but not in the scales and shoot. Oxalate accumulation occurred mainly in the young new scales originating from the basal part of shoot. Most of all the oxalate in the inner new scales and the outer old scales was in the form of Ca-oxalate. The fact that Ca and oxalate contents in old scales remained constant after planting to the flowering stage indicated that Ca and oxalate in bulb scales are not reserve nutrients supporting plant growth. Alternatively Ca-oxalate accumulated in scales appeared to be a stable end-product.     

Localization of MT2a Gene promoter expression is different from the site(s) of copper accumulation in the roots of transgenic Arabidopsis thaliana

Accumulation of mRNA for MT2a, a metallothionein of Arabidopsis thaliana, is known to be upregulated by excess copper (Cu). We compared the localization of the promoter activity of the MT2a gene and the accumulation site(s) of CU in the roots of transgenic A. thaliana. Open reading frame of the β-glucuronidase (GUS) gene was fused with the MT2a gene promoter and introduced into A. thaliana. Strong GUS activity was observed in the region near or within the stele in the presence of CU at a high concentration (high-CU condition). Electron probe X-ray micro-analysis demonstrated that under high-CU conditions, CU accumulated most abundantly in the cortex, where GUS activity was not significantly induced. These results indicate that the sites showing the MT2a promoter activity and CU accumulation did not coincide with each other, suggesting that CU is not a direct activator of the MT2a promoter.     

Rapid and reversible nitrate inhibition of nodule growth and N2 fixation activity in soybean (Glycine max (L.) Merr.)

Nodulated soybean (Glycine max. (L) Merr. cv. Williams) plants were hydroponically cultured, and various combinations of 1-week culture with 5 or 0 mm nitrate were applied using 13-d-old soybean seedlings during three successive weeks. The treatments were designated as 0-0-0, 5-5-5, 5-5-0, 5-0-0, 5-0-5, 0-5-5, and 0-0-5, where the three sequential numbers denote the nitrate concentration (mm) applied in the first-second-third weeks. The size of the individual nodule was measured periodically using a slide caliper. All the plants were harvested after measurement of the acetylene reduction activity (ARA) at the end of the treatments. In the 0-0-0 treatment, the nodules grew continuously during the treatment period. Individual nodule growth was immediately suppressed after 5 mm nitrate supply. However, the nodule growth rapidly recovered by changing the 5 mm nitrate solution to a 0 mm nitrate solution in the 5-0-0 and 5-5-0 treatments. In the 5-0-5 treatment, nodule growth was completely inhibited in the first and the third weeks with 5 mm nitrate, but the nodule growth was enhanced in the second week with 0 mm nitrate. The nodule growth response to 5 mm nitrate was similar between small and large size nodules. After the 5-5-5, 5-0-5, 0-0-5, and 0-5-5 treatments, where the plants were cultured with 5 mm nitrate in the last third week, the ARA per plant was significantly lower compared with the 0-0-0 treatment. On the other hand, the ARA after the 5-0-0 and 5-5-0 treatments was relatively higher than that after the 0-0-0 treatment, possibly due to the higher photosynthate supply associated with the vigorous vegetative growth of the plants supplemented with nitrate nitrogen. It is concluded that both soybean nodule growth and N₂ fixation activity sensitively responded to the external nitrate level, and that these parameters were reversibly regulated by the current status of nitrate in the culture solution, possibly through sensing of the nitrate concentration in roots and / or nodules.     

Photoassimilate partitioning in hypernodulation mutant of soybean (Glycine max (L.) Merr.) NOD1-3 and its parent williams in relation to nitrate inhibition of nodule growth

Nodule growth of a hypernodulating soybean (Glycine max (L.) Merr.) mutant line NOD1-3 was compared to that of its wild-type parent cv. Williams from 14 to 18 days after planting (DAP) in the absence of nitrate treatment (hereafter referred to as “0 mM treatment”) or with 5 mM nitrate treatment. The growth rate determined by increase in the diameter of the nodules was relatively lower in the mutant NOD1-3 than that of the parent Williams under nitrogen-free conditions (0 mM nitrate). The inhibition of nodule growth by 5 mM nitrate started at 1 d after the onset of the nitrate treatment in Williams, while the inhibition did not occur before the application of the nitrate treatment for 2 d in NOD1-3. The nodule growth was completely inhibited after 2 d in Williams and after 3 d in NOD1-3 during the 5 mM nitrate treatment period. After 4 d of 5 mM nitrate treatment, the nodule dry weight decreased by 22% in NOD1-3 and by 58% in Williams, respectively. The treatment with 5 mM nitrate decreased the acetylene reduction activity (ARA) in NOD1-3 by 60% per plant and by 50% per nodule g DW and these parameters were less sensitive to the treatment than those in Williams in which the inhibition rate was 90% per plant and 80% per nodule g DW. These results indicate that NOD1-3 is partially nitrate-tolerant in terms of individual nodule growth as well as total nodule dry weight and Nz fixation activity. A whole shoot of Williams and NOD1-3 plants was exposed to ¹⁴CO₂ for 120 min followed by 0 or 5 mM nitrate treatment for 2 d, and the partitioning of the photoassimilates among the organs was analyzed. Under 0 mM nitrate treatment, the percentages of the distribution of ¹⁴C radioactivity between the nodules and roots were 63 and 37% in Williams and 89 and 11% in NOD1-3. Under the 5 mM nitrate conditions, the percentages of the distribution of ¹⁴C between the nodules and roots changed to 14 and 86% in Williams and 39 and 61% in NOD1-3, respectively. These results indicated that the hypernodulating mutant NOD1-3 supplied a larger amount of photoassimilates to the nodules than to the roots under nitrogen-free conditions, and that the nitrate depression of photoassimilate transport to the nodules was less sensitive than that of the parent line.     

Effect of placement of coated urea fertilizer on root growth and rubidium uptake activity in soybean plant

Abstract

We reported in the previous paper (Takahashi et al. 1991) that the deep placement of slow release N fertilizer (coated urea) contributed to a stable increase of soybean (Glycine max L. Merr.) yield. In the previous study we observed that the deep placement of coated urea did not depress appreciably the nitrogen fixation by root nodules although fertilizer N was efficiently utilized. We assumed that the N absorbed from the roots in the deep layers did not cause nodule senescence, contributed to the maintenance of the leaf activity during the maturation stage, and that the increase in the availability of carbohydrate and N improved seed production. In the current report the effects of placement of coated urea fertilizer on the root growth and activity were studied by measuring the root dry weight and Rb absorption activity.     

Sensitivity and specificity of a commercial BSE kit for the detection of ovine scrapie

To examine the sensitivity of a commercially available bovine spongiform encephalopathy (BSE) kit (NippIBL) for the detection of ovine scrapie, 50 scrapie‐positive ovine samples from the UK, and 54 scrapie‐negative ovine samples from Japan were obtain and tested using this kit. The sensitivity and specificity of NippIBL for ovine samples were 96% and 100%, respectively. The detection limit of the abnormal isoform of prion protein (PrP^Sc) of NippIBL was examined using diluted scrapie‐positive samples. The sensitivity of NippIBL to ovine scrapie was 3–10 times superior to that of another commercial BSE diagnosis kit. Thus, the NippIBL kit proved more effective for the detection of ovine scrapie.     

Haplotype C of growth hormone (GH) gene in Japanese Black cattle: Structure of GH protein and a novel method for detection of the gene

From a series of studies on single nucleotide polymorphisms (SNPs) in the bovine growth hormone (GH) gene of Japanese Black cattle, the type‐C (127^Val and 172^Met) that is specific for this breed has been intensively focused upon because of the economic importance for carcass traits, such as intramuscular oleic acid contents. In the present study, we intended to analyze the 3‐D structure of GH of haplotype C, and developed a novel method to detect the type C gene. Three‐D analysis of the type C protein showed that the amino acid residues (127^Val and 172^Met), which are present in the third and fourth helixes, respectively, and are important for binding with GH receptors, are shifted to deeper positions in the molecule compared with that for type A (127^Leu and 172^Thr), implying the alteration of binding interaction with receptors. A novel, efficient and cost‐effective method (Dot‐blot‐SNP technique) for type C genotyping was successfully established, of which the basal method was a reported genotyping of SNPs for a large number of plants, reducing the cost to 10% or less of direct sequencing.