Skeletal development and deformities in cultured larval and juvenile seven-band grouper, Epinephelus septemfasciatus (Thunberg)

The seven‐band grouper, Epinephelus septemfasciatus (Thunberg), is currently recognized as a potential new species for aquaculture in Japan. This study describes normal and abnormal skeletal development of the jaw and vertebrae in cultured larvae and early juveniles of E. septemfasciatus. The ontogenetic stages at which skeletal deformities of jaw and vertebra developed were also described for this species. Osteological observations were made using a clearing and staining method for larvae and soft X‐ray photographs for juveniles. A high incidence of skeletal deformities was observed in the jaws and vertebral column during the larval and juvenile stages. Most of the jaw deformities were explained by an abnormal maxilla curvature. Jaw deformities were visually evident from flexion stage after ossification of the deformed elements. Deformities in the vertebral column (mostly lordosis) were observed from the post‐larval stage and became more evident as growth proceeded. The lordosis generally occurred on the positions of the 8–11th vertebra. These types of deformities are compared with those of other species, and possible causative factors of the skeletal deformities are discussed.
     

Quinone profiling of bacterial populations developed in the surface layer of volcanic mudflow deposits from Mt. Pinatubo (the Philippines)

The diversity of bacterial populations developed in the surface layer (0-0.25 m depth) of volcanic mudflow deposits from the Mt. Pinatubo volcano (the Philippines) was investigated using quinone profiling. Samples were collected from sites (named N and S1) that had been hit repeatedly by mudflows during successive rainy seasons after the violent eruption of 1991 and also from sites (F1 and F3) covered by mudflow in 1991 but with no deposition in following years. The total microscopic count ranged from 10⁸ g⁻¹ (N and S1 sites) to 3.9×10⁹ g⁻¹(site F3). In the N sample only three quinone species were detected, while the quinone profiles of samples from sites S3 and F3 showed higher diversity. Tetrahydrogenated menaquinone with eight isoprenoid units [MK-8 (H₄)] was the predominant quinone species in the sample from site N, while MK-8, MK-8 (H₂), MK-8 (H₄), MK-9 (H₄) and MK-9 (H₈) were found as major quinones in the sample from site F3. Because these MK species are known to be the major respiratory quinones of the Actinobacteria, this bacterial group is expected to predominate in the land with primary vegetation recovery following the impact of the volcanic mudflow.     

Postnatal development of hypoplastic thymus in semi-lethal dwarf pet/pet males

The petit rat (pet/pet) is a new semi-lethal dwarf mutant with anomalies in the thymus and testes, defects inherited as a single autosomal recessive trait. At birth, these pet/pet rats show low birth weight and extremely small thymuses; at 140 days of age, their thymuses show abnormal involution. In the present study, we examined early postnatal development of hypoplastic pet/pet thymuses. In addition to being hypoplastic at birth, pet/pet thymus growth was almost completely impaired during the early postnatal period. As shown by cellular incorporation of BrdU, the mitotic activity was lower in pet/pet than in normal thymuses, and terminal deoxynucleotidyl transferase dUTP nick end labeling assays showed that apoptosis occurred more often in pet/pet than in normal thymus cells during the first few days after birth. These results indicate that postnatal development of the hypoplastic pet/pet thymus is defective due to the reduced proliferation and increased apoptosis of thymic cells.     

Finding of a highly efficient ZFN pair for Aqpep gene functioning in murine zygotes

The generation efficiencies of mutation-induced mice when using engineered zinc-finger nucleases (ZFNs) have been generally 10 to 20% of obtained pups in previous studies. The discovery of high-affinity DNA-binding modules can contribute to the generation of various kinds of novel artificial chromatin-targeting tools, such as zinc-finger acetyltransferases, zinc-finger histone kinases and so on, as well as improvement of reported zinc-finger recombinases and zinc-finger methyltransferases. Here, we report a novel ZFN pair that has a highly efficient mutation-induction ability in murine zygotes. The ZFN pair induced mutations in all obtained mice in the target locus, exon 17 of aminopeptidase Q gene, and almost all of the pups had biallelic mutations. This high efficiency was also shown in the plasmid DNA transfected in a cultured human cell line. The induced mutations were inherited normally in the next generation. The zinc-finger modules of this ZFN pair are expected to contribute to the development of novel ZF-attached chromatin-targeting tools.     

A cytochrome C oxidase model catalyzes oxygen to water reduction under rate-limiting electron flux

We studied the selectivity of a functional model of cytochrome c oxidase's active site that mimics the coordination environment and relative locations of Fe(a3), Cu(B), and Tyr(244). To control electron flux, we covalently attached this model and analogs lacking copper and phenol onto self-assembled monolayer-coated gold electrodes. When the electron transfer rate was made rate limiting, both copper and phenol were required to enhance selective reduction of oxygen to water. This finding supports the hypothesis that, during steady-state turnover, the primary role of these redox centers is to rapidly provide all the electrons needed to reduce oxygen by four electrons, thus preventing the release of toxic partially reduced oxygen species.     

Is It Possible to Use 90Sr and 137Cs As Tracers for the Aeolian Dust Transport?

A noble approach for the estimation of the deposition of the Asian dust over Japan by using atmospheric anthropogenic radioactivity, ⁹⁰Sr and ¹³⁷Cs, is proposed. Those radioactivities once deposited globally onto the ground by the past nuclear test, etc. are resuspended along with the surface soil particles in the air by the storm and deposited again on the ground. The difference in ¹³⁷Cs/⁹⁰Sr activity ratios in the surface soil between dry and wet climatic conditions gives a clue to know about the source of the dust. It was found that the average activity ratio in the deposited material (average: 2.1, n=82) at MRI, Tsukuba in the 1990s is not close to that of the surface soil taken in neighborhood (median: 6.8, n=8), which had been considered as the primary source. While, it is close to that of the soil samples taken in the arid area in the Asian continent (median: 2.0, n=4), which is the one of the source regions of the aeolian dust. Thus we can reasonably assume that deposited dust in Tsukuba is brought not only from the neighboring fields, etc. but also from the arid area in the continent. Using a simple two-component model it was estimated that the Asian dust may transport about 90% of ⁹⁰Sr and 70% of ¹³⁷Cs depositions observed in Tsukuba in the 1990s. Also, Asian dust may transport about 2/3 of the dust deposited in Tsukuba.     

Diurnal Variations in Photosynthesis,Stomatal Conductance and Leaf Water Relation in Sorghum Grown with or without Silicon under Water Stress

Sorghum [Sorghum bicolor (L.) Moench] was grown hydroponically with or without 50 ppm silicon (Si), and exposed to water stress from 10 days after sowing (DAS). At 15 and 23 DAS, we measured dry weight and diurnal variations in photosynthetic rate (P _N), stomatal conductance (g _s), transpiration rate (T), leaf water potential (ψ _L), and water uptake rate (23 DAS only). The reduction in dry weight at 23 DAS caused by water stress was ameliorated by silicon. Under water stress, silicon-treated seedlings showed higher g _s, P _N, and T than untreated ones. ψ _L remained almost constant within treatments throughout the daytime. Water uptake rate was reduced by water stress, but the reduction was ameliorated by silicon. We conclude that silicon enhanced water uptake and g _s, improving water supply to the leaves. These effects of silicon occurred soon after exposure to water stress.     

Effects of copper on the decomposition of plant residues,microbial biomass,and β-glucosidase activity in soils

Abstract

Two types of soils (Brown Lowland soil and Ando soil), which were artificially enriched with different amounts of Cu, were incubated with or without pulverized orchard grass for 12 weeks at 25°C. For both soils with and without orchard grass amendment, the amount of CO₂ evolved over the 12-week period of incubation decreased by the enrichment with Cu at a concentration exceeding 1,000 mg kg^?1 soil. The decrease of the mineralization of added orchard grass in the Cu-enriched soil was conspicuous especially during the initial period of incubation. The amount of microbial biomass C at the end of the incubation was significantly reduced by the Cu enrichment regardless of the amendment with orchard grass. The relative decrease of the soil microbial biomass was much greater than that of the soil respiration. The amount of biomass C was negatively correlated with the amount of 0.1 M CaCl₂-extractable Cu as a logarithmic function. On the other hand, the β-glucosidase activity at the end of the incubation was not significantly affected by the presence of Cu in the soils without orchard grass amendment and increased with the increase in the amount of enriched Cu in the orchard grass-amended soils.     

Large-scale survey of frequency of forest walking and related factors in a Japanese population inhabiting a large city, and comparison of an urban area and a rural area

The frequency of forest walking among the general population is a major topic of study in forest science. The objectives of this study were threefold: to assess the frequency of forest walking among Japanese residents of Nagoya, a large city; to evaluate differences among frequency of forest walking by participants from a large city, an urban area (Shizuoka; 4,666 participants), and a rural area (Yakumo Town, Hokkaido; 397 participants) in previous studies; and to examine factors related to frequency of forest walking. The survey, by self-administered questionnaire, in the major city of Nagoya was conducted between June 2008 and May 2010. In all, 5,158 participants (M/F, 1,466/3,692; mean age ± SD [range], 52.5 ± 10.3 [35–69] years) were included in the analysis. The proportions of frequency of forest walking ≥ once/month and ≥ once/year were 10.9 % (M/F, 15.1/9.3 %) and 46.1 % (51.0/44.1 %), respectively. In multiple logistic regression analysis, significant differences were noted among study sites for the adjusted odds ratio for frequency of forest walking. Overall, the order of highest to lowest frequency of forest walking was Shizuoka > Nagoya > Yakumo. Factors related to frequency of forest walking were common among the three study sites. Higher frequency of forest walking was associated with male sex and older age; the most relevant factor related to frequency of forest walking was its enjoyment level. Further studies will be required to clarify why these factors are related to frequency of forest walking.     

The Process and Development Mechanism of Age-related Fibrosis in the Pancreatic Islets of Sprague-Dawley Rats: Immunohistochemical Detection of Myofibroblasts and Suppression Effect by Estrogen Treatment

The mechanism of spontaneous islet fibrosis in Sprague-Dawley rats was investigated. Using sections of the pancreas in naive males aged 26 to 102 weeks old and 26-week-old males injected with β-estradiol 3-benzoate (EB), the incidence of lesions and histological scores of fibrosis were examined in conjunction with immunohistochemistry for α-smooth muscle actin (α-SMA), platelet-derived growth factor receptor-α (PDGFRα) and estrogen receptor-α (ERα). The incidence of islet fibrosis increased in 78-week-old animals compared to the 26-week-old animals, and the incidence of atrophy in the fibrotic islet increased in animals over 52 weeks old. α-SMA and PDGFRα were positively stained mainly in fibrotic/inflammatory islets, and the histological score of α-SMA in the fibrotic islet decreased age-dependently. Notably, α-SMA and PDGFRα were co-expressed in inflammatory islets with a high score at all ages. The positive index of ERα in the EB-treated group increased when compared with that of the naive group. However, it was independent of the existence of fibrosis. In contrast, the score of α-SMA and PDGFRα decreased in the EB-treated group. In conclusion, it was clarified that a part of age-related fibrosis in islets became atrophy with age, and α-SMA-positive myofibroblasts were considered to contribute to the development of fibrosis. Strong PDGFRα stainability in fibrotic/inflammatory islets may imply that myofibroblasts were stimulated by PDGF to produce an extracellular matrix. Although estradiol has been known to suppress fibrosis/inflammation in the islet, nuclear-located ER-dependent signaling was considered not to be involved in the suppression mechanism. EB possibly affected the inhibition of the appearance of myofibroblasts.