Exogenous coronatine,but not coronafacic acid or methyl jasmonate,restores the disease phenotype of a coronatine-defective mutant of <Emphasis Type="Italic">Pseudomonas syringae</Emphasis> pv. <Emphasis Type="Italic">tomato</Emphasis> on tomato seedlings

Coronatine (COR) functions as a virulence factor in the interaction of Pseudomonas syringae pv. tomato strain DC3000 with tomato and Arabidopsis. COR consists of two moieties, coronafacic acid (CFA) and coronamic acid (CMA). Both COR and CFA function as structural and functional analogues of jasmonic acid (JA) and related signaling compounds such as methyl jasmonate (MeJA) and JA-isoleucine (JA-Ile). The precise function of COR and whether MeJA functions as an analogue of COR in disease development are not known. In this study, we analyzed whether the COR-defective mutant DB29, which is a CFA⁻ CMA⁻ mutant of DC3000, could be complemented for virulence via the exogenous application of COR, CFA, or MeJA. When tomato seedlings were inoculated with DB29 and supplemented with exogenous COR, the DB29 population multiplied in tomato seedlings and induced disease phenotypes similar to wild-type DC3000. Although the addition of exogenous MeJA or CFA enhanced the multiplication of DB29, wild-type disease phenotypes could not be restored with these compounds. Furthermore, inoculation of DB29 along with exogenous COR, but not MeJA or CFA, suppressed the expression of defense-related genes and increased the accumulation of reactive oxygen species, which are associated with severe chlorosis. Taken together, our results suggest that although COR targets the jasmonate pathway by mimicking JA, the function of COR in disease development is distinctly different from MeJA or CFA.     

Long-lived volcanism on the lunar farside revealed by SELENE Terrain Camera

We determined model ages of mare deposits on the farside of the Moon on the basis of the crater frequency distributions in 10-meter-resolution images obtained by the Terrain Camera on SELENE (Selenological and Engineering Explorer) (Kaguya). Most mare volcanism that formed mare deposits on the lunar farside ceased at approximately 3.0 billion years ago, suggesting that mare volcanism on the Moon was markedly reduced globally during this period. However, several mare deposits at various locations on the lunar farside also show a much younger age, clustering at approximately 2.5 billion years ago. These young ages indicate that mare volcanism on the lunar farside lasted longer than was previously considered and may have occurred episodically.     

The effects of selective logging on stand structure and the regeneration of subboreal forests in Hokkaido, northern Japan

We investigated the effects of selective logging on stand structure and regeneration in selectively logged subboreal forests in Taisetsuzan National Park in Hokkaido in northern Japan. The basal area decreased and the size structure of trees altered in the stands studied due to repeated, intense selective logging, in which larger trees were cut down as a priority. Sapling density in the stands was much lower than that in primary forests. In the simple and multiple regression analyses that were used to estimate the effects of selective logging on sapling density, sapling density had a significant positive correlation with tree density and had little correlation with the density of logged stumps or the height ofSasa (dwarf bamboo) growing on the forest floor. These results suggest that the establishment sites around canopy trees influenced the establishment of saplings, rather than the gaps caused by selective logging. However, both the coefficient of determination and the standardized partial regression coefficient of multiple regression analysis were higher for the stand with a dense cover ofSasa than for the stand with a sparse cover ofSasa. Thus, the success of regenerating forests with selective logging depends on both the site of advanced regeneration and the light conditions that regulate growth.     

Distribution and physical properties of colluvium and saprolite in unchannelized valleys in Tsukuba Experimental Basin, Japan

To clarify the role of colluvium and saprolite in the hydrological processes of a forested mountain, the thickness and the physical properties of them were investigated at the Tsukuba Experimental Basin. We measured their thickness using a penetrometer, surveyed soil profiles, and analyzed undisturbed cylindrical samples for measurements of physical properties. At the zero-order basin, which is mainly covered by volcanic ash, the colluvium is mostly over 1.0 m in thickness. Along the axis of the basin, we found colluvium over 6.0 m thick. The saprolite thickness is heterogeneously distributed over the hillslopes and along the axis of the hollow, where it is rather thick. The physical properties of shallow colluvium, deep colluvium and saprolite, particularly bulk density and total porosity, are different. Thick colluvium and saprolite play an important role as a buffer against direct runoff.     

Compensation of the birefringence of a polymer by a birefringent crystal

We report a method for compensating the birefringence of optical polymers by doping them with inorganic birefringent crystals. In this method, an inorganic birefringent material is chosen that has the opposite birefringence to that of the polymer and has rod-shaped crystals that are oriented when the polymer chains are oriented. The birefringence of the polymer is thus compensated by the opposing birefringence of the crystal. Birefringence is minimized in various polymer optical devices by adjusting process conditions, because it degrades the performance of devices. This method minimizes it, independent of process conditions, which potentially improves the productivity of devices.     

Hpa1 secretion via type III secretion system in <Emphasis Type="Italic">Xanthomonas oryzae</Emphasis> pv. <Emphasis Type="Italic">oryzae</Emphasis>

In many Gram-negative plant pathogenic bacteria the type III secretion system (TTSS), encoded by hrp genes, is essential for pathogenicity in the host and induction of a hypersensitive reaction (HR) in nonhost plants. The expression of hrp genes has been suggested to be repressed in complex media, whereas it is induced in planta and under certain in vitro conditions. We recently reported that XOM2 medium allows efficient hrp expression by Xanthomonas oryzae pv. oryzae. In this study, we investigated hrp-dependent secretion of proteins by the bacteria in vitro. Using modified XOM2, in which bovine serum albumin was added and the pH was lowered to 6.0, we detected at least 10 secreted proteins and identified one as Hpa1. This is the first evidence of protein secretion via TTSS in X. oryzae pv. oryzae.     

Specific inhibition of spore germination of <Emphasis Type="Italic">Alternaria brassicicola</Emphasis> by fistupyrone from <Emphasis Type="Italic">Streptomyces</Emphasis> sp. TP-A0569

Fistupyrone (FP), a metabolite from Streptomyces sp. TP-A0569, inhibited the in vivo infection of Chinese cabbage seedlings by Alternaria brassicicola. To detect the possible action sites of FP, the effect of FP on the infection behavior of A. brassicicola and A. alternata was investigated. When spores of A. brassicicola were suspended in FP solution and inoculated on host leaves, FP at 0.1ppm significantly inhibited spore germination, appressorial formation, and infection hypha formation of A. brassicicola. Host-specific AB-toxin production and lesion formation by A. brassicicola spores were also reduced significantly by treatment with FP 1ppm. The effect of FP seemed to be irreversible because significant washing of FP-treated spores with distilled water (DW) did not change the inhibitory effects. In contrast, A. alternata isolates such as Japanese pear pathotype, apple pathotype, and saprophyte behaved almost equally in both FP- and DW-treated spores. Mycelial dry weight in potato dextrose broth and mycelial diameters on potato dextrose agar, gelatin glucose agar, and Czapek solution agar of both A. brassicicola and A. alternata were not different with or without addition of FP. These results indicate that FP at low concentrations has a fungicidal effect on spores of A. brassicicola but not on spores of A. alternata; FP also does not affect the vegetative phase of these fungi.     

Examination of the Lunatic fringe and Uncx4.1 expression by whole-mount in situ hybridization in the embryo of the CKH-Jsr (jumbled spine and ribs) mouse

The CKH-Jsr (jumbled spine and ribs) mouse was found as a spontaneous mutant with malformation of vertebrae, that is, a short trunk and kinky tail. We examined Lunatic Fringe (Lfng) and Uncx4.1 expression in the presomitic mesoderm (PSM) and somites of Jsr-mutant (CKH-Jsr/+) embryos to elucidate pathogenesis of the Jsr mutation. Expression pattern of Lfng in the PSM of Jsr-mutant embryos was similar to that of the normal (C57BL/6) embryos. However, expression pattern of Uncx4.1 in the somites of Jsr-mutant embryos was impaired to be irregular and mosaic, suggesting that the anterior-posterior (A-P) polarity is disordered in the Jsr mutant. These results indicate that the Jsr mutation disrupts the A-P polarity of somites during the somitogenesis without altering Lfng expression pattern in the PSM.     

Congenital hepatic arteriovenous fistula with intrahepatic portosystemic shunt and aortic stenosis in a dog

Examination of a 2-month-old male golden retriever presented to the hospital revealed malnutrition, ascites, cardiac murmur and hyperammonemia. Identification of subaortic stenosis and hepatic arteriovenous fistula was made through ultrasonography and angiocardiography. In addition, intrasurgical mesenteric portography showed an intrahepatic portosystemic shunt. The dog did not show portal hypertension and secondary multiple extrahepatic portosystemic shunts. Surgical correction was attempted after medical treatment. The hepatic artery branch which was connected to the hepatic arteriovenous fistula was separated, and completely ligated using silk ligature. However, the separation of the intrahepatic shunt blood vessel was unsuccessful and the dog died 15 hr postoperatively.     

A case of fatal systemic toxoplasmosis in a cat being treated with cyclosporin A for feline atopy

Acute systemic toxoplasmosis was diagnosed in a 4-5-year-old, male, Domestic Short Hair cat, which had been on cyclosporine A immunomodulatory therapy for feline atopy, over an 8-month period. Cyclosporin A (CsA) has shown promising results as a immunosuppressive agent in the cat for the treatment of eosinophilic plaque and granulomas, allergic cervico-facial pruritus, feline atopy and other immune-mediated dermatoses. However, inhibition of T-lymphocyte function by CsA is believed to have predisposed this cat to the development of a newly acquired, acute Toxoplasma gondii infection, as characterized by severe hepatic and pancreatic pathology in conjunction with the heavy parasite load demonstrated on immunohistochemical (IHC) stains for T. gondii. Cats on CsA therapy appear to be at risk of developing fatal systemic toxoplasmosis.