Morphology and size of embryos recovered from superovulated cows.

A total of 691 normal embryos were recovered from 183 superovulated donor cows on the 5th and 6th days after the first insemination, and were examined for their morphology and size in relation to their developmental stage. There was no significant difference in the thickness of the zona pellucida, the diameter of the cell mass, and the overall diameter of the embryos among zygotes, 2-, 4-, 8- and 16-cell embryos, and morulae. In the blastocyst stage, however, the diameter of the cell mass and the overall embryo diameter were significantly greater and the zona pellucida was significantly thinner than in the earlier-stage embryos. The volume of the blastomere significantly decreased from zygote to morula in proportion to the increase in the number of blastomeres. The volume of the cell mass of 2-cell embryos was decreased by about 30% compared with that of zygotes and no increase in the volume of the cell mass was observed during the progression from 2-cell stage to morula. The diameter of the cell mass and the overall diameter of morulae recovered on the 6th day after the first insemination were significantly greater than those of morulae recovered on the 5th day.     

Echo-ranging neurons in the inferior colliculus of bats

Bats measure the distance to an object in terms of the time lag between their outgoing orientation sounds and the returning echo. For measurement of the time lag, the latency of response of a neuron to a stimulus must be nearly constant regardless of the stimulus amplitude and envelope. Otherwise, a large error would be introduced into the measurement. Bats have neurons that are specialized for echo ranging.     

Neural attenuation of responses to emitted sounds in echolocating rats

Bats of the family Vespertilionidae enmit strong ultrasonic pulses for echolocation. If such sounds directly stimulate their ears, the detection of echoes from short distances would be impaired. The responses of lateral lemniscal neurons to emitted sounds were found to be much smaller than those to playback sounds, even when the response of the auditory nerve was the same to both types of sounds. Thus, responses to self-vocalized sounds were attenuated between the cochlear nerve and the inferior colliculus. The mean attenuation was 25 decibels. This neural attenuating mechanism is probably a part of the mechanisms for effective echo detection.     

Cortical neurons sensitive to combinations of information-bearing elements of biosonar signals in the mustache bat

The auditory cortex of the mustache bat, Pteronotus parnellii rubiginosus, is composed of functional divisions which are differently organized to be suited for processing the elements of its biosonar signal according to their biological significance. Unlike the Doppler-shifted-CF (constant frequency) processing area, the area processing the frequency-modulated components does not show clear tonotopic and amplitopic representations, but consists of several clusters of neurons, each of which is sensitive to a particular combination (or combinations) of information-bearing elements of the biosonar signal and echoes. The response properties of neurons in the major clusters indicate that processing of information carried by the frequency-modulated components of echoes is facilitated by the first harmonic of the emitted biosonar signal. The properties of some of these neurons suggest that they are tuned to a target which has a particular cross-sectional area and which is located at a particular distance.     

Inhibitory effects of Zingiber officinale Roscoe derived components on aldose reductase activity in vitro and in vivo

Ginger (Zingiber officinale Roscoe) continues to be used as an important cooking spice and herbal medicine around the world. Scientific research has gradually verified the antidiabetic effects of ginger. Especially gingerols, which are the major components of ginger, are known to improve diabetes including the effect of enhancement against insulin-sensitivity. Aldose reductase inhibitors have considerable potential for the treatment of diabetes, without increased risk of hypoglycemia. The assay for aldose reductase inhibitors in ginger led to the isolation of five active compounds including 2-(4-hydroxy-3-methoxyphenyl)ethanol (2) and 2-(4-hydroxy-3-methoxyphenyl)ethanoic acid (3). Compounds 2 and 3 were good inhibitors of recombinant human aldose reductase, with IC50 values of 19.2 +/- 1.9 and 18.5 +/- 1.1 microM, respectively. Furthermore, these compounds significantly suppressed not only sorbitol accumulation in human erythrocytes but also lens galactitol accumulation in 30% of galactose-fed cataract rat model. A structure-activity relationship study revealed that the applicable side alkyl chain length and the presence of a C3 OCH3 group in the aromatic ring are essential features for enzyme recognition and binding. These results suggested that it would contribute to the protection against or improvement of diabetic complications for a dietary supplement of ginger or its extract containing aldose reductase inhibitors.     

Root and crown rot of strawberry caused by Pythium helicoides and its distribution in strawberry production areas of Japan

Pythium species were isolated from seedlings of strawberry with root and crown rot. The isolates were identified as P. helicoides on the basis of morphological characteristics and sequences of the ribosomal DNA internal transcribed spacer regions. In pathogenicity tests, the isolates caused root and crown rot similar to the original disease symptoms. Multiplex PCR was used to survey pathogen occurrence in strawberry production areas of Japan. Pythium helicoides was detected in 11 of 82 fields. The pathogen is distributed over six prefectures.     

Two new species,Phytophthora nagaii sp. nov. and P. fragariaefolia sp. nov., causing serious diseases on rose and strawberry plants,respectively, in Japan

A new disease of rose was noticed in Chiba Prefecture of Japan in 1968, and the pathogen was initially identified as Phytophthora megasperma based on morphological characteristics. Similar Phytophthora isolates have since been collected from rose plants in Chiba, Kanagawa, and Shizuoka Prefectures. In 2005, several Phytophthora isolates were recovered from crowns of strawberry plants in Hokkaido Prefecture. These were considered to be members of a new species. In this study, we re-examined all these isolates using morphological and physiological studies and a multilocus phylogenetic analysis. The rose and strawberry isolates were mostly similar morphologically and physiologically, with some exceptions. The rose isolates differed significantly from P. megasperma sensu stricto and other related Phytophthora species. The rose and strawberry isolates had external proliferation of sporangia, characteristic funnel-shaped oogonia, predominantly paragynous antheridia, and fast growth rates of 10.5 mm/24 h at an optimum temperature of 28 °C. In the multilocus phylogenetic tree constructed using sequences from the rDNA ITS regions, rDNA LSU, and the translation elongation factor 1-α, β-tubulin and coxI genes, they formed a distinct monophyletic group in clade 7 with strong bootstrap support. The rose and strawberry isolates separated into two distinct groups. The results indicate that the rose and strawberry isolates constitute two separate species, designated here as Phytophthora nagaii and P. fragariaefolia.     

Current classification of Ralstonia solanacearum and genetic diversity of the strains in Japan

Ralstonia solanacearum is the causal organism of bacterial wilt of more than 200 species representing 50 families of plants in tropical, subtropical, and warm temperate regions in the world. Traditionally classified into five races based on differences in host range, R. solanacearum has also been grouped into six biovars on the basis of biochemical properties. With recent developments in molecular biology, various DNA-based analyses have been introduced and used to confirm that this binary system does not completely represent the diversity within R. solanacearum strains. Therefore, a new hierarchical classification scheme has been suggested, which defines R. solanacearum as a species complex and reorganized the concept of the species as a monophyletic cluster according to a phylogenetic analysis based on genomic sequence data. Here we discuss the current bacterial wilt situation and genetic relationships based on the recent classification system of Japanese R. solanacearum strains as well as worldwide strains. We also review the genetic, biochemical, and pathological characteristics of R. solanacearum strains, in particular, those affecting potato and Zingiberaceae plants as distinctly important pathogens in relation to continuously problematic and recent emergent diseases in Japan.     

Relationships of culm surface area to other culm dimensions for bamboo, Phyllostachys pubescens

We determine the relationships of culm surface area to other culm dimensions for one of the largest bamboo species, Phyllostachys pubescens Mazel ex Houzeau de Lehaie. A total number of 150 sample culms were collected from a stand of P. pubescens in Mt. Toshima, Kumamoto Prefecture, western Japan. The culm surface area for each sample was calculated, and then the relationships of the culm surface area to basal area and product of diameter at breast height (dbh) and culm height were analyzed. The relationship between culm surface area and basal area could be described successfully by the power equation, whereas there was a linear relationship of culm surface area to product of dbh and height. Although the regression equations determined here would be useful in estimating culm surface area of P. pubescens, it is necessary to select an appropriate equation depending on the purpose and available time and labor.     

Effects of Yuzu (Citrus junos) Peel from Waste as an Aquaculture Feed Supplement on Growth,Environmental Load,and Dark Muscle Discoloration in Yellowtail Seriola quinqueradiata

Beneficial utilization of yuzu (Citrus junos) peel was investigated to improve the commercial value of cultured yellowtail fish. The antioxidant effects of grated yuzu peel from pomace (yuzu paste) on prevention of dark muscle discoloration during storage in sliced yellowtail fish were tested. Four diets were prepared, containing 0, 10, 50, and 100 g yuzu paste in a 1,450-g diet (wet basis). Fish were fed one of the four diets for 10 weeks. Growth performance was not significantly different among the dietary groups, but fish fed a diet containing 100-g yuzu paste showed the least average body weight and a significant increase in fecal amount and fat levels in the feces, which suggest low digestibility and low absorption. Dark muscle discoloration was significantly reduced in all yuzu dietary groups compared to the control group during storage at 4°C. The optimal supplementation of yuzu paste in the fish diet is very effective at maintaining fish flesh freshness as a finishing diet without causing additional phosphorus or nitrogen pollution of the sea and inhibiting fish growth. This study provides a new way to utilize waste yuzu peel, which also helps reduce waste from yuzu processing.