Effect of an Introduced Phytoene Synthase Gene Expression on Carotenoid Biosynthesis in the Marine Diatom Phaeodactylum tricornutum

Carotenoids exert beneficial effects on human health through their excellent antioxidant activity. To increase carotenoid productivity in the marine Pennales Phaeodactylum tricornutum, we genetically engineered the phytoene synthase gene (psy) to improve expression because RNA-sequencing analysis has suggested that the expression level of psy is lower than other enzyme-encoding genes that are involved in the carotenoid biosynthetic pathway. We isolated psy from P. tricornutum, and this gene was fused with the enhanced green fluorescent protein gene to detect psy expression. After transformation using the microparticle bombardment technique, we obtained several P. tricornutum transformants and confirmed psy expression in their plastids. We investigated the amounts of PSY mRNA and carotenoids, such as fucoxanthin and β-carotene, at different growth phases. The introduction of psy increased the fucoxanthin content of a transformants by approximately 1.45-fold relative to the levels in the wild-type diatom. However, some transformants failed to show a significant increase in the carotenoid content relative to that of the wild-type diatom. We also found that the amount of PSY mRNA at log phase might contribute to the increase in carotenoids in the transformants at stationary phase.     

Quantitative mapping of kelp forests (Laminaria spp.) before and after harvest in coastal waters of the Shiretoko Peninsula,Hokkaido, Japan

In the Shiretoko Peninsula, a World Natural Heritage site, the sustainable management of kelp forests has drawn public attention because of the economic and ecological importance of kelp. We spatially estimated the distributions of kelp forests in the Shiretoko Peninsula before and after harvest. Field surveys were conducted in coastal waters (23.74 km²) at the ends of July and August 2008, immediately before and after harvest. Data on the presence or absence and thickness of the kelp forests were collected via acoustic observation. The data were interpolated using geostatistical methods. Before harvest, the kelp forests were continuously distributed over 5.64 km² (thickness 33–132 cm), especially near the north part of the study area. After harvest, they were sparsely distributed over 2.73 km² (thickness 35–105 cm). In the southern part of the study area, the influence of harvests was observed as declines in forest area. In addition, relatively thickly forested areas formed the majority of the part most likely to be harvested. Selective harvesting for area and size was confirmed though quantitative mapping of kelp forests. The quantitative mapping of both the distribution and harvest of kelp forests was successful.     

Magnesium oxide nanoparticles induce systemic resistance in tomato against bacterial wilt disease

Bacterial wilt is a serious problem affecting many important food crops. Recent studies have indicated that treatment with biotic or abiotic stress factors may increase the resistance of plants to bacterial infection. This study investigated the effects of magnesium oxide nanoparticles (MgO NP) on disease resistance in tomato plants against Ralstonia solanacearum, as well as its antibacterial activity. The roots of tomato seedlings were inoculated with R. solanacearum and then immediately treated with MgO NP; the treated plants showed very little inhibition of bacterial wilt. In contrast, when roots were drenched with a MgO NP suspension prior to inoculation with the pathogen, the incidence of disease was significantly reduced. Rapid generation of reactive oxygen species such as O₂^?˙ radicals was observed in tomato roots treated with MgO NP. Further O₂^?˙ was rapidly generated when tomato plant extracts or polyphenols were added to the MgO NP suspension, suggesting that the generation of O₂^?˙ in tomato roots might be due to a reaction between MgO NP and polyphenols present in the roots. Salicylic acid‐inducible PR1, jasmonic acid‐inducible LoxA, ethylene‐inducible Osm, and systemic resistance‐related GluA were up‐regulated in both the roots and hypocotyls of tomato plants after treatment of the plant roots with MgO NP. Histochemical analyses showed that β‐1,3‐glucanase and tyloses accumulated in the xylem and apoplast of pith tissues of the hypocotyls after MgO NP treatment. These results indicate that MgO NP induces systemic resistance in tomato plants against R. solanacearum.     

Variation in leaf morphology of Quercus crispula and Quercus dentata assemblages among contact zones: a method for detection of probable hybridization

I describe variation in leaf morphology of Quercus crispula and Quercus dentata assemblages within and among their contact zones. Such relationships provide a relatively fast and accurate method for detecting hybridization. Using discriminant function (DF) analysis based on leaf characteristics, I was able to differentiate between these two species in pure zones. In three of five contact zones, the DF scores showed broad, continuous distributions with three or more peaks. The trees showing intermediate leaf morphology are considered to be hybrids. In the other two contact zones, the DF scores showed distinct bimodal distributions, suggesting that Q. crispula and Q. dentata rarely hybridize in these sites. Thus, the method described in this study should be effective for detecting probable hybridization between these two species in contact zones, and the relative frequency of hybridization among contact zones. However, there was likely to be intraspecific variation of Q. crispula between geographic ranges, restricting interpretations to patterns occurring within sites or limited geographic ranges.     

Ectomycorrhizal fungal community of naturally regenerated Pinus thunbergii seedlings in a coastal pine forest

To add to knowledge of ectomycorrhizal (ECM) community structure on the roots of Pinus thunbergii seedlings in a Japanese coastal forest, we sampled naturally regenerated current-year and 1- to 5-year-old seedlings. We classified the 667 root tips on current-year seedlings and the 1,927 root tips on older seedlings into 13 phylotypes based on morphological and genetic analyses. Cenococcum geophilum, members of the families Clavulinaceae, Russulaceae, or Thelephoraceae or the genus Trichophaea, were indicated to be fungi forming P. thunbergii ectomycorrhizas. Among them, C. geophilum and Clavulinaceae sp. 1 were the most or second most dominant species. A species accumulation curve based on the number of samples nearly reached a plateau, with observed species richness equal to 11 species and the Jackknife2 and Chao2 richness estimators indicating 14 and 12 species, respectively. In addition, Simpson’s 1/D was 3.89 and Shannon–Wiener’s H′ was 1.71, indicating a relatively low taxonomic diversity. There was no significant difference in the ectomycorrhizal formation rate, or the occurrence frequency and the number of ECM phylotypes between current-year and older seedlings. These results indicated that less diverse fungi were involved in ectomycorrhizal formation on coastal pine seedlings compared with those in comparable inland forests in the study area.     

古梅灵芝和梅子精抗过敏性作用的研究

抑制组胺游离和肠管收缩等过敏反应的研究表明,对于由Ｃｏｍｐｏｕｎｄ４８／８０或ＩｇＥ抗血清反应引起的老鼠腹腔细胞中组胺的游离及外源组胺引起的土拨鼠肠管的收缩,古梅灵芝和梅子精均有明显的抑制作用．     

Female sex steroid residues in the tissues of steers treated with progesterone and oestradiol-17 beta.

Progesterone, oestrone and oestradiol-17 beta levels in the muscle, fat, liver, kidney and plasma of steers treated with Synovex S, untreated steers, and cows during the normal oestrous cycle, were examined. Progesterone levels in female tissues reached a maximum in the luteal phase and fell to a minimum in the follicular phase. Oestrogen levels (oestrone and oestradiol-17 beta) did not change during the cycle. Progesterone and oestrogen levels in the tissues of steers treated with Synovex S and untreated steers were not statistically different. Tissue progesterone levels in steers were much lower than those in cows during the luteal phase. The highest oestrogen levels were found in the fat of female animals. These results indicate that residue levels of progesterone and oestrogen in the muscle and fat of steers treated with Synovex S were within the physiological range, and lower than those of cows.