Suppressive effect of acetylated glyceride (Bemidetach™EC) on <Emphasis Type="Italic">Tomato yellow leaf curl virus</Emphasis> transmitted by the whitefly <Emphasis Type="Italic">Bemisia tabaci</Emphasis> on greenhouse tomato plants

Acetylated glyceride (Bemidetach?EC)—a food additive—repels adult sweet potato whiteflies (Bemisia tabaci) and inhibits their mating behavior. We evaluated the effects of acetylated glyceride spraying of greenhouse-grown tomato plants on infestation with B. tabaci and the occurrence of Tomato yellow leaf curl virus (TYLCV) disease under commercial-like conditions. The abundance of adult B. tabaci was significantly reduced by three sprayings of acetylated glyceride, and the TYLCV incidence was significantly suppressed to less than 30% of that in the untreated control. These results suggest that acetylated glyceride sprays suppress the secondary spread of TYLCV in greenhouse-grown tomatoes by lessening B. tabaci adult density.     

Histopathology of red crown rot of soybean

Histopathological analyses of red crown rot (RCR) of soybean were performed using field-grown and indoor-grown soybean plants. These analyses revealed that soybean plants formed a periderm to prevent pathogen invasion. When a break formed in the periderm, an additional periderm newly differentiated into the inner cells and prevented pathogen invasion. If the pathogen reached the intravascular tissues, some xylem parenchyma cells died, and the vessels were occluded by gum. Periderm formation and vessel occlusion were observed not only in slightly diseased soybean plants, but also in seriously diseased plants, indicating that both reactions function as part of the defense response against RCR.     

Genome‐wide association studies reveal additional related loci for fatty acid composition in a Duroc pig multigenerational population

The aim of the present study was to detect quantitative trait loci affecting fatty acid composition in back fat and intramuscular fat in a Duroc pig population comprising seventh‐generation pedigrees using genome‐wide association studies (GWAS). In total, 305 animals were genotyped using single nucleotide polymorphisms (SNPs) array and five selected SNPs from regions containing known candidate genes related to fatty acid synthesis or metabolism. In total, 24 genome‐wide significant SNP regions were detected in 12 traits, and 76 genome‐wide suggestive SNP regions were detected in 33 traits. The Sus scrofa chromosome (SSC) 7 at 10.3 Mb was significantly associated with C17:0 in intramuscular fat, while the SSC9 at 13.6 Mb was significantly associated with C14:0 in intramuscular fat. The SSC12 at 1.0 Mb was significantly associated with C14:0 in back fat and the SSC14 at 121.0 Mb was significantly associated with C18:0 in intramuscular fat. These regions not only replicated previously reported loci containing some candidate genes involved in fatty acid composition (fatty acid synthase and stearoyl‐CoA desaturase) but also included several additional related loci.     

Rhodococcus equi virulence plasmids recovered from horses and their environment in Jeju, Korea: 90-kb type II and a new variant, 90-kb type V

Rhodococcus equi was isolated from fecal and soil samples from four native Jeju horse farms and six Thoroughbred farms in Jeju, Korea. The isolates were examined for the presence of virulence-associated 15-17-kDa antigens (VapA) by colony blotting, using the monoclonal antibody 10G5, and for the gene encoding VapA by PCR. R. equi was isolated from all 36 soil samples collected from the 10 farms with between 5.0 x 10(2) and 7.5 x 10(4) colony-forming units (cfu) per gram of soil, and from 37 of 40 fecal samples with between 5.0 x 10(1) and 1.1 x 10 (5) cfu per gram of feces. Virulent R. equi was isolated from seven farms and appeared in 2.0% of isolates (10 of 508). Of the 10 virulent isolates, four contained a 90-kb type II plasmid, which has been found in isolates from the Kiso native horses of Japan, and the other six contained a new variant, which did not display the EcoRI and EcoT22I digestion patterns of the 10 representative plasmids already reported (85-kb types I, II, III, and IV; 87-kb types I and II; 90-kb types I, II, III, and IV). We designated the new variant as the "90-kb type V" plasmid, because its EcoRI digestion pattern is similar to that of the 90-kb type II plasmid. This is the first report of the prevalence of virulent R. equi in Jeju, Korea. The same virulence plasmid type is found in both Korean and Japanese isolates, providing insight into the origin, ancestry, and dispersal of native horses in Korea and Japan.     

No apoptotic cell death of erythroid cells of erythroblastic islands in bone marrow of healthy rats

A possibility of apoptotic cell death in erythropoietic regulation was examined by means of detailed light microscopical histoplanimetry, electron microscopy, the in situ nick-end labeling method, and an immunohistological method in the rat bone marrow. Serum erythropoietin concentrations were shown at normal levels. The erythroid series on a mature process presented several morphological features of apoptosis, i.e. the shrinkage of both nuclei and cytoplasm and the chromatin condensation. In the light microscopical histoplanimetry, however, morphological signs of final apoptotic cell death were never found in any erythroid cell within the erythroblastic islands. This finding was also supported by detailed ultrastructural observation: No erythroid cell bodies were trapped and degraded by the central macrophages of the erythroblastic islands, while the denucleated nuclei with small amount of cytoplasm of late erythroblasts were often trapped and degraded in the macrophages. Nuclear DNA fragmentation was not detected in any erythroblasts, but was detected in the lysosomes of the central macrophages. These findings suggest that erythropoiesis is regulated by other regulatory mechanisms than apoptotic cell death. An additional ultrastructural finding shows that the reticulocytes anchored to the central macrophages are transported into the peripheral blood circulation.     

Molecular epidemiology of VapA-positive Rhodococcus equi in thoroughbred horses in Kagoshima,Japan

The prevalence of virulent R. equi having 15- to 17-kDa antigens (VapA) in fecal isolates from 13 thoroughbred foals and their dams on 5 farms in Kagoshima, Japan, and the plasmid profiles of VapA-positive isolates by restriction fragment digestion patterns were investigated to compare the genotypic variation among virulence plasmids of R. equi isolates from Japan. In total, 218 (24.6%) of 886 isolates from the feces of the 13 foals and 13 (12.5%) of 104 isolates from the feces of their dams demonstrated VapA-positive R. equi. Plasmid DNA preparations of 231 virulent isolates from foals and dams were analyzed by restriction enzyme digestion with endonucleases EcoRI, EcoT22I and HindIII and were divided into 3 types: 172 isolates contained a 90-kb type I plasmid, 57 contained a 90-kb type III plasmid and 2 contained a 90-kb type IV plasmid. This study demonstrates a geographic character in the distribution of virulence plasmids found in VapA-positive isolates from thoroughbred foals in Kagoshima.     

Black Streak of Edible Burdock Caused by Itersonilia perplexans in Japan

Black streak disease of edible burdock (Arctium lappa L.) has been observed periodically in Hokkaido Prefecture, Japan since 1988. Symptoms appeared initially as small, dark brown to black spots on the leaf veins and petioles. The necrotic spots developed longitudinally along the leaf veins or petioles. Diseased leaf veins or petioles occasionally snapped off at the necrotic lesions. An Itersonilia sp. was isolated from rotting leaf veins and petioles. Laboratory inoculations of edible burdock seedlings using ballistospore suspensions produced typical symptoms observed in nature. The fungus had a feathery mycelium and developed a white to pale cream colony color. The mycelium was composed primarily of branched hyphae with clamp connections at the septa. Ballistospores, formed at the apex of inflated cells, were lunate, ovoid to pyriform. The fungus occasionally produced appressoria, chlamydospores and yeast cells. Based on the morphological characteristics, the causal agent was identified as Itersonilia perplexans Derx. Edible burdock strains were also pathogenic to chrysanthemum and caused petal blight. This report is the first of a foliar disease of edible burdock caused by I. perplexans in Japan. Received 8 April 2002/ Accepted in revised form 26 June 2002     

Flagella-mediated motility is required for biofilm formation by Erwinia carotovora subsp. carotovora

To elucidate the role of flagella in biofilm formation by Erwinia carotovora subsp. carotovora EC1, we used a nonflagellate, nonmotile mutant (ΔfliC) and a flagellate, nonmotile mutant (ΔmotA). A biofilm-inducing medium, which contains the yeast peptone (YP) medium plus the salts of M-63 minimal medium, supported biofilm formation to a greater extent than either the YP or Luria Bertani (LB) medium alone. We demonstrated that both the ΔfliC and ΔmotA mutants greatly reduced their ability to form a biofilm on the surface of the wells of polyvinyl chloride (PVC) microtiter plates. The inability of both mutants to form biofilm on the PVC surface was further confirmed with phase-contrast microscopy. Both aflagellate (ΔfliC) and flagellate (ΔmotA) nonmotile mutants were equally defective in attachment to the PVC surface. The treatment of bacteria with the protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP), which inhibits the motility of this organism, reduced greatly the biofilm formation. Based on these results, flagella-mediated motility may play an important role in biofilm formation of E. carotovora subsp. carotovora EC1.     

Nitrogen budget of a rehabilitated forest on a degraded granitic hill

Rehabilitated forests established about 100 years ago on denuded lands in a hilly granitic area are widespread in the Kyoto–Osaka area, the second largest megalopolis in Japan. From 2001 to 2003, we monitored the annual nitrogen (N) budget of a rehabilitated forest watershed dominated by Quercus serrata and Ilex pedunculosa. The ion concentrations of bulk rain in the watershed were similar to those of other watersheds in Japan. The annual bulk rain input of N ranged from 5.1 to 6.3 kg N ha⁻¹ year⁻¹, and the N deposition from throughfall and stem-flow ranged from 7.5 to 8.2 kg N ha⁻¹ year⁻¹. Estimated annual outputs of N from the stream ranged from 3.3 to 10.6 kg N ha⁻¹ year⁻¹. These results indicate that the amount of N deposition in this area is less than that in urban Tokyo (>10 kg N ha⁻¹ year⁻¹), but the N output of the watershed is comparable with that of the Tokyo area. We discuss the characteristics of N dynamics in rehabilitated forests, focusing on the biogeochemical processes of this watershed.     

Root morphology and nutritional status of Japanese red cedar saplings subjected to in situ levels of aluminum in forest soil solution

There is little information on the effects of in situ levels of aluminum (Al) in the forest soil solution on the root morphology of Japanese red cedar (Cryptomeria japonica D. Don). We evaluated whether morphological and nutritional changes in the white roots of Japanese red cedar saplings grown in glass-bead culture for 18 weeks occurred in response to Al solutions at five concentrations: 0 (control), 0.05, 0.1, 0.5, and 1.0mM. Branching white roots treated with 0.5 or 1.0mM Al had some stunted, brown, thickened tips. Their mean lengths were significantly shorter than those of roots treated with 0.05 or 0.1mM Al. The maximum diameters of white roots treated with 0.5 or 1.0mM Al were significantly larger than those of the control. Treatment with 0.5 or 1.0mM Al reduced the concentrations of Ca and Mg in the white roots and increased the concentration of Al compared with the control. These results indicate that between 0.1 and 0.5mM Al, a drastic change occurs in the effects of Al on the morphology and nutritional status of white roots of Japanese red cedar saplings, and suggest that the Al levels in Japanese forest soils may induce morphological changes in the white roots.