Basal levels and responses to glucose infusion of plasma glucose and insulin in beef steer before and after the end of the growing phase on pasture

We examined the effect of grazing during the growing phase on plasma glucose and insulin behavior at the end of the growing phase and at the early stage of the subsequent fattening phase in beef steers. From 13 to 45 weeks of age (growing phase), crossbred beef steers were grazed with minimal supplement (group G: n = 5) or housed while being fed on hay and concentrate (group H: n = 5). Following this phase, both groups were housed for finishing (fattening phase). At the end of the growing phase, group G showed faster plasma glucose disappearance after intravenous glucose infusion, with a smaller plasma insulin response, compared with group H. At the third week of the fattening phase, group G still showed higher glucose tolerance, although they experienced abrupt changes in nutritional and environmental factors. The results suggest that grazing during the growing phase probably improves the glucose tolerance and insulin response to glucose infusion in steers compared with animals that were housed during the corresponding period, and the improved properties may persist at least a few weeks after the commencement of fattening.     

Susceptibility-inducing factor (suppressor) from Blumeria graminis f. sp. hordei has no effect on the primary infection of the fungus

When fungal germlings, after forming haustoria of Blumeria graminis f. sp. hordei (B. graminis), were removed from the surfaces of barley coleoptiles by cellulose acetate, followed by challenge inoculation with the non-pathogen Erysiphe pisi, they infected the nonhost barley coleoptile cells. This phenomenon was not observed on the coleoptile surface when the fungal germlings of B. graminis were removed before the formation of haustoria. Also, when the surface was inoculated with the pathogen of barley B. graminis as a challenger, after removing the fungal germlings of inducer post haustorial formation, the penetration efficiency of the fungi increased significantly compared with that of the control. Furthermore, when we extracted the crude-susceptibility inducing factor (suppressor) from coleoptiles before and after the formation of haustoria of B. graminis, suppressor activity against infection with E. pisi was observed only in the extract of barley coleoptiles that included haustoria of B. graminis about 18 h or later after inoculation. Surprisingly, however, the extract did not increase the penetration efficiency of B. graminis significantly. Thus, we hypothesize that the suppressor extracted from barley coleoptiles in which B. graminis had formed haustoria has no effect on increasing the penetration efficiency of the primary infection from the appressorium of B. graminis but has an effect on the infection with non-pathogen E. pisi.     

Radioactive particles in soil,plant, and dust samples after the Fukushima nuclear accident

Environmental samples of soil, plant and air dust collected after the Fukushima Daiichi Nuclear Power Plant accident were analyzed by autoradiograph, and significant amounts of radioactive particles containing higher cesium-134 (¹³⁴Cs) and cesium-137 (¹³⁷Cs) were found. Most of the radioactive soil particles were clay sized. The main part of the radioactivity and radioactive particles of air dust was detected from the 1.1–2.0μm fraction of an Andersen sampler filter. A considerable part of the radioactive particles on the air dust filter were not water soluble. Radioactive particles attached to outdoor plant leaves persisted for nearly 1 year. Thus, soil, leaf and air dust similarly contained sparingly water-soluble, micron-sized radioactive particles each with comparable ranges of elevated radio-Cs. A sheet dilution method was proposed and used to select and purify these radioactive particles. Using selected radioactive particles, the relation between area × gray value on autoradiograph and radioactivity was estimated. Radioactivity per particle was up to a few Bq and the geometrical average radioactivity of detected particles was around 0.1 Bq per particle or less. The configuration, chemical composition, origin and formation mechanisms of the radioactive particles require clarification.     

Identification of facultative anaerobic bacteria isolated from the intestine of the minke whale <Emphasis Type="Italic">Balaenoptera acutorostrata</Emphasis> by 16S rRNA sequencing analysis

There are few reports in the literature about the isolation of bacteria from whale intestine. In this report, we counted colony-forming units in the feces obtained from three female common minke whales (Balaenoptera acutorostrata). The number of colony-forming units ranged from (2.2 ± 0.4) × 10⁵ to (8.9 ± 2.0) × 10⁸ per gram (wet weight) of excrement. 16S rRNA gene sequences of 141 isolates were determined. These strains were identified as Enterococcus faecalis, Enterococcus sp., Enterobacter cloacae, Enterobacter sp., Escherichia coli, Edwardsiella ictaluri or Clostridium sp. The data suggested that the facultative anaerobic population of the intestinal bacterial flora of the minke whale was similar to that of ground mammals.     

Random dispersal of Bursaphelenchus xylophilus (Nematoda: Aphelenchoididae) in Pinus densiflora branches

Bursaphelenchus xylophilus is the causative agent of pine wilt disease. These nematodes disperse in the cortical and wood resin canals of host tree branches in the early stage of infection. To determine whether the dispersal can be regarded as diffusion, we inoculated B. xylophilus into living or boiled Pinus densiflora branch sections and investigated the spatial distribution 24 hr later. Assuming that some nematodes disperse randomly in the axial direction of branch sections and the rest remain at the inoculation site, the coefficient of diffusion (D) by dispersers was estimated to be 23.7–40.7 and 109.4 cm²/day for the living and boiled branches, respectively. The proportion of nondispersers was estimated to be 0.46–0.79 and 0.52 for the living and boiled branches, respectively. When the nematodes were inoculated at the centre of upright living branch sections, they dispersed up and down at similar D values of 7.4 and 7.9 cm²/day, respectively.     

Arbuscular mycorrhizal fungal communities associated with some pioneer plants in the lahar area of Mt. Pinatubo,Philippines

An extensive area has been buried due to the repeated occurrence of mud flows (lahars) derived from volcanic deposits during the eruption of Mt. Pinatubo in the Philippines. Most of the area was covered with sparse vegetation consisting of only a few gramineous pioneer plants such as Saccharum spontaneum (site SV). However dense vegetation consisting of wild leguminous plants such as Calpogonium mucunoides showed a patch distribution (site DV). In 1999, we investigated the community composition of AMF at these two sites. S. spontaneum at both sites was slightly colonized with AMF while the leguminous plants were highly colonized. Spores of AMF were collected from the rhizosphere of these plants. Eight spore morphotypes were identified; one each for Acaulospora and Entrophospora colombiana, two for Glomus, one for Paraglomus, and three for Scutellospora. Part of the 18S rRNA gene of AMF colonizing the plant roots was amplified with AMF-specific primers, NS31 and AM1, cloned and sequenced. Fifty-three AMF clones were phylogenetically classified into 8 phylotypes as follows: one each for Acaulospora and E. colombiana, five for Glomus, and one for Scutellospora. Both molecular and morphological examinations showed that the diversity of AMF was comparable to that in other temperate ecosystems with abundant vegetation and did not differ significantly between sites SV and DV, regardless of the vegetation cover. Furthermore, S. spontaneum supported diverse AMF species in spite of its scant growth at site SV. E. colombiana was mostly associated with C. mucunoides. Significance of AMF for the primary plant succession in the lahar area was analyzed.     

Dissipationless quantum spin current at room temperature

Although microscopic laws of physics are invariant under the reversal of the arrow of time, the transport of energy and information in most devices is an irreversible process. It is this irreversibility that leads to intrinsic dissipations in electronic devices and limits the possibility of quantum computation. We theoretically predict that the electric field can induce a substantial amount of dissipationless quantum spin current at room temperature, in hole-doped semiconductors such as Si, Ge, and GaAs. On the basis of a generalization of the quantum Hall effect, the predicted effect leads to efficient spin injection without the need for metallic ferromagnets. Principles found here could enable quantum spintronic devices with integrated information processing and storage units, operating with low power consumption and performing reversible quantum computation.     

Neuronal calcium sensor 1 and activity-dependent facilitation of P/Q-type calcium currents at presynaptic nerve terminals

P/Q-type presynaptic calcium currents (IpCa) undergo activity-dependent facilitation during repetitive activation at the calyx of the Held synapse. We investigated whether neuronal calcium sensor 1 (NCS-1) may underlie this phenomenon. Direct loading of NCS-1 into the nerve terminal mimicked activity-dependent IpCa facilitation by accelerating the activation time of IpCa in a Ca2+-dependent manner. A presynaptically loaded carboxyl-terminal peptide of NCS-1 abolished IpCa facilitation. These results suggest that residual Ca2+ activates endogenous NCS-1, thereby facilitating IpCa. Because both P/Q-type Ca2+ channels and NCS-1 are widely expressed in mammalian nerve terminals, NCS-1 may contribute to the activity-dependent synaptic facilitation at many synapses.     

Estimation of mean tree height using small-footprint airborne LiDAR without a digital terrain model

In order to estimate mean tree height using small-footprint airborne light detection and ranging (LiDAR) data, a digital terrain model (DTM), which is a continuous elevation model of the ground surface, is usually required. However, generating accurate DTMs in mountainous forests using only the LiDAR data is laborious and time consuming, because it requires human-assisted methods, especially in the forests with poor laser penetration rates. Based on our previous finding that a hypothetical continuous surface model passing through the predominant tree tops (hereafter, called the “top surface model” or TSM) might be nearly parallel to a DTM, we assumed that the vertical difference between the TSM and the ground return was the mean tree height. According to this assumption, we propose a new methodology that does not require a DTM to estimate mean tree height. This method completely, automatically, and directly estimates mean tree height (MTH _E) from the LiDAR data without requiring a regression analysis using reference data. From the relationships between the MTH _E and the observed mean tree height (MTH _O) in different hinoki cypress forests, we demonstrate that this method effectively estimates the mean tree height with nearly 1-m accuracy.