Symptom development of the resinous stem canker caused by inoculation withCistella japonica ontoChamaecyparis obtusa

Cistella japonica was inoculated onto the stems of youngChamaecyparis obtusa trees, and the development of external and internal symptoms was investigated for five years. Most lesions started exuding resin from May to July during the first growing season after inoculation, while a few lesions started exuding resin during the second growing season. Resin exudation lasted for two successive years on most lesions, and during successive three, four, or five years on some lesions. Resin exuded excessively in the secondary phloem of the lesions and resin cysts frequently developed there. The lesions where cambial tissue was necrosed occupied 18% of all the lesions and the resinous areas expanded to a larger size than those where resin simply exuded in the phloem.Ci. japonica was reisolated from some inoculated lesion tissues at a high frequency. The isolation frequency of the fungus from some lesion tissues two and more years later was zero or low and that ofCryptosporiopsis abietina was high. This work was supported by a grant from the Forest Agency of the Japanese Government.     

Relations between the colorimetric values and densities of sapwood

Color measurements were made for sapwood specimens of 26 hardwood species. The densities of the specimens ranged from 258.5 to 945.6kg/m³. The colorimetric values and densities were compared among the species. The tristimulus values ofX, Y, andZ were poorly correlated with the densities. The chromaticity coordinatex had a good linear correlation with the densities of the wood specimens, especially in the transverse planes. The transverse plane of wood fibers is thought to emphasize the relative values in the long wavelength region of the visible ray.Part of this report was presented at the 49th annual meeting of the Japan Wood Research Society, Tokyo, April 1999     

Paternity determination of captive bottlenose dolphins (Tursiops truncatus) using microsatellite DNA analysis

We applied previously published PCR primer pairs to amplify alleles at three polymorphic microsatellite loci to determine the genetic relationship of 6 bottlenose dolphins (Tursiops truncatus) that were living together in a Japanese aquarium. The three microsatellite loci were sufficient to determine the haplotype relationships of the six dolphins, which represented three different generations. It was confirmed that this genotyping method is simple and economical for assessing, establishing and maintaining genetic diversity in captive populations and will become a very effective technique for ex situ conservation in aquariums and zoos.     

Brain abscess in a Japanese black calf: utility of computed tomography (CT)

Computed tomography (CT) was used for diagnosis of brain abscess in a 6-month-old, Japanese black calf presented with neurological dysfunction, compulsive circling and vision disturbance. CT images showed asymmetric lateral ventricles, and presence of intra-cranial multiple low absorption lesions surrounded by capsule suggestive of abscess in the right cerebral hemisphere. Postmortem examination revealed marked swelling of right cerebral hemisphere and olfactory bulb. Multilocular large abscess containing creamy pus was found to occupy most area of periventricular and lateral ventricle. Fusobacterium necrophrum was isolated from the abscess contents as the causative agent. These results demonstrate that CT is useful tool for tentative diagnosis of bovine brain abscess.     

Investigation into the dosage of dietary sphingomyelin concentrate in relation to the improvement of epidermal function in hairless mice

We previously found that dietary sphingomyelin (SPM) concentrate from bovine milk improved epidermal function. In this study, we investigated the dosage of dietary SPM concentrate from bovine milk in relation to the improvement of epidermal function. Thirteen-week-old hairless male mice were separated into four experimental groups, each fed one of four types of experimental diet: the control group, the low SPM group, the medium SPM group and the high SPM group. The mice were each fed the experimental diet for 6 weeks. The stratum corneum hydration and the transepidermal water loss (TEWL) were measured using a Corneometer and a Tewameter at 3 weeks and 6 weeks. After the feeding period, ceramides in the stratum corneum were analyzed. We found that the stratum corneum hydration in all the SPM groups was significantly higher than that in the control group, whereas TEWL in all the SPM groups was significantly lower than that in the control group. Ceramides increased significantly in mice fed the medium SPM diet and statistically tended to increase in mice fed the high SPM diet. Our results indicate that a daily intake of 17 mg SPM concentrate is enough to improve epidermal function in hairless mice.     

Pathogenicity of Stemphylium lycopersici isolated from rotted tobacco seeds on seedlings and leaves

A preemergence damping-off of tobacco (Nicotiana tabacum L.) was found in Fukuoka, Japan, in 2009. A fungus repeatedly isolated from the black-rotted seeds reproduced the symptoms in tobacco seeds, and the preemergence damping-off developed after flower and soil inoculation with the fungus. Brown spots and blight developed on leaves of tobacco seedlings after inoculation with the isolate. The fungus was reisolated from the rotted seeds and blighted leaves. The causal fungus was identified as Stemphylium lycopersici based on morphology and phylogenetic analysis. This is the first report to confirm the pathogenicity of S. lycopersici in tobacco in the world.     

Abnormal morphology in megalopae of the swimming crab,Portunus trituberculatus during seed production: causes and prevention

The occurrence of morphologically immature megalopae, which retain zoeal features such as dorsal spines and furcae of telson, is closely correlated with larval mass mortality during seed production of the swimming crab Portunus trituberculatus in Japanese hatcheries. To determine the cause of immature megalopal morphology, zoeae were reared with various supplementary schedules and density of diets (rotifer, Artemia and phytoplanktons including Chlorella vulgaris and Nannochloropsis oculata). In addition, to assess the relationship between immature morphology and endocrine control, the effect of causative dietary factor was compared with the effect of eyestalk ablation at various timing during zoeal development. Megalopal immature morphology was more distinct in Chlorella‐supplemented groups than in Nannochloropsis‐supplemented groups. High density Chlorella supplementation was associated with the highest incidence of immaturity and resulted in larval mass mortality. The premoult of the third zoeal stage was identified as a critical period at which Chlorella supplementation led to the highest incidence of immaturity. This critical period coincided with the critical period at which larval metamorphosis was regulated by the eyestalk neurosecretory system. Our results suggested that the occurrence of immature megalopal morphology under culture conditions is most likely caused by phytoplankton (especially, Chlorella) supplementation, which disrupts the endocrine regulation. On the basis of our results, we successfully prevented the occurrence of immature megalopal morphology in 500 L tanks by excluding the influence of phytoplankton before the critical period (i.e. discontinuing phytoplankton supplementation and supplying rotifer cultured with non‐phytoplankton materials).     

Characterization of Japanese <Emphasis Type="Italic">Rhizoctonia solani</Emphasis> AG-2-1 isolates using rDNA-ITS sequences,culture morphology,and growth temperature

Rhizoctonia solani AG-2-1 is classified into three subsets (Subsets 1–3) based on the rDNA-ITS sequence. Few Japanese isolates, however, have been phylogenetically analyzed. To understand the distribution and diversification of AG-2-1 isolates in Japan, we examined 23 Japanese AG-2-1 isolates (15 from Hokkaido, the northernmost island, and eight from NARO Genebank) in terms of rDNA-ITS sequences, culture morphology, and temperature-dependent growth characteristics. Of these, 15 isolates were found to belong to Subset 1. One isolate, which formed a light brown colony with concentric rings and grew slowly at 25 °C, was classified into Subset 2. Six isolates had varied culture morphology and relatively faster growth than Subset 1 isolates at 30 °C. They formed a clade on the phylogenetic tree, designated clade HK, with cauliflower isolates from Belgium and the Netherlands, with a bootstrap value of 47%, and were separate from the three known subsets. Sequence similarity in the rDNA-ITS region for this clade ranged from 98.2 to 100%, whereas clade HK isolates had 96.7–98.6% similarity with the isolates in each subset. This result suggests that clade HK is likely an independent intragroup within AG-2-1, although the rDNA-ITS sequences in this clade were variable. One isolate was not assignable to any clade because it was intermediate between isolates in clade HK and Subset 2. This is the first report describing variation among rDNA-ITS sequences of Japanese AG-2-1 isolates.