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.     

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.     

Effects of the number of pollen grains on cold tolerance at the booting stage in rice lines with QTLs for cold tolerance

This study was conducted to clarify the relationship between the number of pollen grains per anther and spikelet fertility under low temperature conditions in the rice cultivars and lines including lines with quantitative trait loci (QTL) for cold tolerance, adapted to the Tohoku region of northern Japan. Cold-water treatment decreased anther length, the number of pollen grains per anther, and spikelet fertility in all cultivars and lines. The number of pollen grains was proportional to anther length in all cultivars and lines and under all temperatures. Spikelet fertility decreased with decreasing the number of pollen grains in cold-water treatments at 18.5 and 19.3?°C. ‘Ouu 415’, with the qLTB3 QTL for cold tolerance, had 28% more pollen grains and 9% higher spikelet fertility than the recurrent parent, ‘Hitomebore’, in the 18.5?°C cold-water treatment, suggesting that qLTB3 increased both parameters. Lines with the qCTB8 QTL for cold tolerance had significantly more pollen grains in two of the three years and significantly higher spikelet fertility in all three years in the 19.3?°C cold-water treatment, suggesting that qCTB8 reinforced cold tolerance. Ctb1, a proposed cold-tolerance QTL, had no effect on the number of pollen grains or spikelet fertility. In conclusion, the cultivars and lines with more pollen grains had a higher cold tolerance. Some of QTLs were inferred to increase the number of pollen grains and reinforce cold tolerance.     

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.     

Epizootiological study of tick-borne encephalitis virus infection in Japan

Tick-borne encephalitis virus (TBEV) is a zoonotic agent causing severe encephalitis in humans. Rodent species that are potential hosts for TBEV are widely distributed in various regions in Japan. In this study, we carried out large-scale epizootiological surveys in rodents from various areas of Japan. A total of 931 rodent and insectivore sera were collected from field surveys. Rodents seropositive for TBEV were found in Shimane Prefecture in Honshu and in several areas of Hokkaido Prefecture. These results emphasize the need for further epizootiological and epidemiological research of TBEV and preventive measures for emerging tick-borne encephalitis in Japan.