Species identification method for <Emphasis Type="Italic">Scombrops boops</Emphasis> and <Emphasis Type="Italic">Scombrops gilberti</Emphasis> based on polymerase chain reaction-restriction fragment length polymorphism analysis of mitochondrial DNA

ABSTRACT:   Gnomefish Scombrops boops and Scombrops gilberti are commercially important fishes in Japan, but these species are often confused in the markets because of their morphological similarity. To identify these two species, we performed nucleotide sequencing and restriction fragment length polymorphism (RFLP) analysis on 16S ribosomal RNA (rRNA) gene and the control region in mitochondrial DNA. Five and 12 nucleotide substitutions were observed between species in the 777-bp 16S rRNA gene and 471-bp control region, respectively. Diagnostic restriction sites for discriminating between S. boops and S. gilberti were found in the 16S rRNA gene, but not in the control region. Polymerase chain reaction (PCR)–RFLP analysis using two enzymes, Eco NI and Mva I, clearly discriminated between S. boops and S. gilberti identified by meristic characters. The PCR–RFLP analysis identified most of the 168 Scombrops young caught in the coastal waters of the Izu and Miura peninsulas as S. boops , suggesting that S. gilberti juveniles are rare in this area.     

Comparison of flower color with anthocyanin composition patterns in evergreen azalea

In evergreen azaleas, major anthocyanins were detected from petals of wild species and cultivars by HPLC analysis. Depending on flower color, all samples were divided into three groups: red, purple or white, using the Japan color standard for horticultural plants. The chromatic components a* and b* values of red group samples showed a convergent distribution, whereas those of purple group samples showed a wider distribution. According to the HPLC analysis, red group samples had two to four major anthocyanins, and those of the purple group had two to six major ones. In contrast, no anthocyanins were detected in the white group petals, although anthocyanidins were detected. These results suggest that the anthocyanin constitution of the purple group flowers is more varied than that of the red group flowers, and this wider variety among purple flowers contributes to extending the diversity of flower color in evergreen azalea.     

cDNA cloning and complete primary structures of myosin heavy chains from brushtooth lizardfish Saurida undosquamis and wanieso lizardfish S. wanieso fast skeletal muscles

ABSTRACT:   The complete cDNA sequences encoding predominant types of myosin heavy chain (MYH) in the fast skeletal muscle were determined for brushtooth lizardfish Saurida undosquamis and wanieso lizardfish S. wanieso , which are used as materials for preparing high-quality surimi-based products. The cDNA consisted of 5973 and 5987 bp, respectively, and both encompassed an open reading frame encoding a polypeptide of 1936 amino acid residues. Brushtooth and wanieso lizardfish MYH showed the amino acid sequence identity of 92–93% to white croaker MYH, which was higher than that of 90% to walleye pollack MYH. The putative binding sites for ATP, actin, and regulatory and essential light chains in the subfragment-1 region of brushtooth lizardfish MYH exhibited a high identity with white croaker counterparts as well as the sequences of subfragment-2 and light meromyosin. In contrast, phylogenetic tree, constructed by the neighbor-joining method based on mitochondrial 16S rRNA gene, revealed that the two lizardfish species formed a cluster with walleye pollack, which was paraphyletic with white croaker. Therefore, a good reputation for lizardfish and white croaker to have a high thermal-gel forming ability seemed to be reflected by MYH rather than biological similarity as revealed by the mitochondrial 16S rRNA gene.     

Influence of volcanic ash sediments on spore adhesion of the red alga Gelidium elegans from the coastal seabed around Miyakejima Island, Japan

The populations of red alga Gelidium elegans along the coast of Miyakejima Island were severely damaged by a volcanic eruption in 2000. The effect of this volcanic eruption has been long lasting, and populations of this red alga still have not recovered. We investigated the effect of seabed sediment particles derived from volcanic ash on the substrate adhesion of G.?elegans spores. The analysis provides evidence that increasing amounts of sediment particles result in lower adhesion rates of G.?elegans spores, and that smaller sediment particles have a greater influence on adhesion. The amount of seabed sediment particles around Miyakejima Island was 9.3?C1815.4?mg/cm². This amount has changed greatly from year to year. The adhesion rate of G.?elegans spores in water around Miyakejima Island was 0?% at all points in 2008 and 2010, but it was estimated as 6.3?C38.6?% in 2009. These results suggest that there is significant inhibition of algal spore adhesion by seabed sediment particles derived from volcanic ash around Miyakejima Island.     

Improvement in recruitment of Japanese sardine with delays of the spring phytoplankton bloom in the Sea of Japan

To evaluate the impact of temporal variation of primary productivity on the recruitment of Japanese sardine (Sardinops melanostictus) in the Sea of Japan, the phenology of sea surface phytoplankton abundance was estimated from 8 day multiple satellite (SeaWiFS, MODIS‐Aqua, MERIS, and VIIRS) derived sea surface chlorophyll (SSChl) a concentrations from January 1998 to December 2015. Because relationships between SSChl a and in situ chlorophyll a concentrations were significantly different among periods based on the satellite combinations used, maximum and minimum SSChl a concentrations of 1 year were relativized as 1 and 0, respectively. Spatio‐temporal variation of relativized SSChl a concentrations was determined by using empirical orthogonal function (EOF) analysis. Scores in the first EOF mode denoted the basin‐scale variations of SSChl a concentrations in the Sea of Japan, and the major peak from the end of February to the end of May displayed the spring bloom. The logarithm of recruitment per spawner (LNRPS) for sardine was positively affected by delays in the start and end dates of the spring phytoplankton bloom. The delay of the date of the lowest sea surface temperature contributed to the delay of the end of the spring bloom during the period 1998–2015 and elevated the LNRPS during the period 1982–2015. Sardine spawns in the southern Sea of Japan from April to May, hence, delays of the spring bloom prolonged its overlap with sardine larval periods, and thus improved the recruitment of Japanese sardine in the Sea of Japan.     

Intrapancreatic accessory spleen mimicking pancreatic insulinoma with intrapancreatic metastasis in a cat

An 11-year-old neutered male Domestic Shorthair cat presented with a 3-month history of hypoglycemia, two episodes of seizure, and intermittent tick-like signs. Serum biochemistry revealed severe hypoglycemia associated with high insulin concentrations. Dynamic abdominal computed tomography (CT) indicated two pancreatic masses, which were enhanced most during the late arterial phase but had different degrees and variations of attenuation. Partial pancreatectomy was performed. Histopathology and immunohistochemistry confirmed that one mass was an insulinoma and the other was an ectopic splenic tissue, consistent with the differences in imaging findings. When an intrapancreatic lesion with hyper-attenuation on dynamic abdominal CT is detected, not only insulinoma or metastasis of malignancies but also intrapancreatic accessory spleen (IPAS) should be considered as differential diagnoses.     

Identification of the medicinal off-flavor compound formed from ascorbic acid and (E)-hex-2-enal

A test apple beverage made up of apple juice (20%), high-fructose corn syrup (11.5%), citric acid (0.43%), trisodium citrate (0.02%), apple-odor flavor (0.1%), and ascorbic acid (0.02%) was stored at 40 °C and then analyzed for the change of odor in the beverage. Although no thermoacidophilic bacteria (TAB) were detected, a medicinal off-flavor was perceived after the 8 weeks of storage. Model experiments on the ingredients of the test apple beverage revealed that the off-flavor compound had been formed by ascorbic acid and (E)-hex-2-enal. Synthesis and NMR (1H, 13C, HMQC, and HMBC) analyses identified the compound as 6-propylbenzofuran-7-ol. The odor quality, retention index (RI), and mass spectrum of synthetic 6-propylbenzofuran-7-ol were identical with those of the medicinal odor compound from the test apple beverage. Sensory evaluation revealed the recognition thresholds for medicinal odor were 31.4 ppb in water and 24.0 ppb in apple beverage, and the detection thresholds were 19.6 ppb in water and 8.6 ppb in apple beverage, respectively. The quantified concentration of 6-propylbenzofuran-7-ol formed in test apple beverage was 90 ppb, approximately. This concentration was well above the odor threshold, so it was concluded that the compound was the source of the medicinal off-flavor.     

Kinetic Parameters of Gross N Mineralization of Peat Soils as Related to the Composition of Soil Organic Matter

Peat land has been considered as an alternative type of land for agricultural development especially in the tropics. In the present study, the N-supplying capacity, one of the most important soil properties in terms of crop production, of peat soils was examined. Ten peat soil samples were collected from Indonesia, Malaysia, and Japan. Gross N mineralization in the soil samples was estimated using a zero-order model, and kinetic parameters of mineralization were determined using a simple type model. Soil organic matter composition was investigated using ¹³C CPMAS NMR. Mineralization potential ( N ₀), apparent activation energy ( E _a), and mineralization rate constant ( k ) ranged between 571–2,445 mg kg⁻¹, 281–8,181 J mol⁻¹, and 0.009–0.020 d⁻¹, respectively. Although none of the parameters showed a significant correlation with the soil C/N ratio, a negative correlation was observed between the k value and the ratio of the proportion of alkyl C in total C to that of O -alkyl C estimated by ¹³C CPMAS NMR. The latter suggested that the k values were higher in the peat soils relatively rich in readily decomposable organic matter including carbohydrates.     

Attaining inter-subgeneric hybrids in fragrant azalea breeding and the inheritance of organelle DNA

Inter-subgeneric hybrids were successfully obtained in reciprocal cross combinations between evergreen azaleas (Rhododendron nakaharae and its hybrids) and fragrant deciduous azaleas (R. arborescens and R. viscosum) for the purpose of fragrant evergreen azalea breeding. Nuclear and organelle DNA of these hybrids was investigated using PCR-RFLP markers. Viable hybrid seedlings have nuclear ribosomal DNA (nrDNA) inherited biparentally, mitochondrial DNA (mtDNA) from the seed parent, and chloroplast DNA (cpDNA) from the deciduous azalea, regardless of cross combination. These results suggest that the chloroplast genome from deciduous azaleas and the nuclear genome from evergreen azaleas are compatible in viable hybrid progenies.     

Chemical characteristics and potential source of fulvic acids leached from the plow layer of paddy soil

To understand better the chemical characteristics and source of dissolved organic matter (DOM) leached from the plow layer of rice paddies, a lysimeter study was conducted, which simulated submerged paddy topsoil during rice growth. The fulvic acid (FA) fraction in the percolation water from the lysimeter was collected by adsorption onto insoluble polyvinylpyrrolidone (PVP), and the temporal variations in its elemental composition, molecular size distribution, IR spectra, ¹³C CPMAS NMR spectra, and δ¹³C values were investigated. The proportion of the FA fraction to bulk DOM varied greatly, but the chemical characteristics of the FA fraction did not change appreciably during the experimental period. Thus, it is considered that the changes in the DOM composition in percolation water were mainly due to the differing contributions of the FA fraction. Further, to investigate the source of the FA fraction in the leachate, the chemical characteristics of the FA fraction in the leachate were compared with those extracted from the plow layer soil. A sequential extraction of the FA fraction was conducted using a sequence of water, 0.25 M Na₂SO₄, 0.1 M Na₄P₂O₇ (pH 7.0), 0.1 M Na₄P₂O₇ (pH 10.5), and NaBH₄+0.1 M Na₄P₂O₇ (pH 10.5). It was found that the water- and 0.25 M Na₂SO₄-extractable fractions, which were most mobile, were not the only source of the FA fraction in the leachate. The small molecular size sub-fraction of the NaBH₄+0.1 M Na₄P₂O₇ (pH 10.5)-extractable FAs, most of which are probably bound mainly to iron oxides, are considered to be another source of the FA fraction leached from the plow layer of paddy fields.