Identification and use of a wild plant with antimicrobial activity against Ralstonia solanacearum, the cause of bacterial wilt of potato

Fresh aerial tissue and roots of 14 wild plants in Okinawa prefecture were investigated for their antimicrobial activity against Ralstonia solanacearum , which causes bacterial wilt of potato. A 70% aqueous ethanol extract of fresh aerial tissue of Geranium carolinianum L. showed strong antimicrobial activity against R. solanacearum . This extract also showed antimicrobial activity against the pathogens causing common scab of potato and soil rot of sweet potato. The antimicrobial substance could be extracted with hot water, and was effective against R. solanacearum in soil. In the field test, a treatment combining incorporation of dried aerial tissue into the soil and solarization was highly effective for control of bacterial wilt of potato. These findings suggest that G. carolinianum L. could be used as a biological agent for the control of bacterial wilt of potato.     

Hepatic AA amyloidosis in a cat: cytologic and histologic identification of AA amyloid in macrophages

A 3‐year‐old, spayed female, Domestic Shorthair cat presented with anorexia, lethargy, vomiting, probable hemoabdomen, and multiple masses on the right lateral liver lobe. Clinicopathologic and imaging abnormalities included anemia, azotemia, icterus, and hepatomegaly with hypoechoic masses. On cytologic evaluation of a fine‐needle aspiration of a liver mass there was abundant extracellular pink‐ to purple‐colored material between hepatocytes. The amorphous material was stained with direct fast scarlet (DFS), and green birefringent areas were observed under polarized light, confirming the presence of amyloid. A unique finding on the cytologic smear were macrophages containing amorphous and fibrillar amyloid‐like protein. Histopathologic examination using H&E and Congo red staining confirmed amyloid deposits within the space of Disse, along the sinusoids, portal tracts, blood vessel walls, and within the cytoplasm of macrophages. Immunohistochemical staining with anti‐AA amyloid antibodies further confirmed the presence of AA amyloid. To the author's knowledge, this is the first report of the cytologic finding of AA amyloid protein within macrophages and DFS stain detection of amyloid on a cytologic smear.     

Three dogs under 2 years of age with heartworm caval syndrome

Heartworm caval syndrome (CS) occurred in three dogs under 2 years of age. A 23-month-old dog was recovered by surgical and medical treatments, but the other 2 dogs (15 and 21 months old) died. Necropsy demonstrated 12 heartworms in the 15-month-old dog and 8 worms in the 21-month-old dog. Histopathologically, pulmonary arterial embolism caused by dead worms and thrombi were observed in these cases. The findings suggested that CS could develop regardless of canine age and worm burden if pulmonary arterial embolism related to worm death or thrombus formation were induced.     

Isolation of Salmonella from diarrheic feces of pigs

A survey of Salmonella was carried out in fecal samples of 887 pigs with diarrhea collected from 235 pig farms between April 1996 and March 2001. Salmonella was isolated from 84 feces (9.5%) of 887 pigs and from 45 (19.1%) of 235 farms. The higher prevalence was found in weaned pigs (12.4%) and fattening pigs (17.3%) than in sows (4.2%) and suckling pigs (4.5%). Isolation rates of S. Typhimurium were higher from weaned and fattening pigs than from the others. Therefore, risk of horizontal infection of S. Typhimurium will increase, if no adequate health managements are practiced when weaned and fattening pigs have diarrhea.     

Experimental evidence of a pathogenic change caused by homologous recombination between endogenous and introduced dysfunctional Avr-Pita genes in Pyricularia oryzae

To provide experimental evidence that somatic homologous recombination (HR) is involved in the instability and diversification of the avirulence gene Avr-Pita in Pyricularia oryzae, we generated a dysfunctional Avr-Pita homolog and integrated it into strain Hoku-1 containing Avr-Pita. In the transformants, the occurrence of somatic HR events between Avr-Pita and the dysfunctional homolog was confirmed by PCR–RFLP. Germlings from conidia from the HR-positive transformants had lost the avirulence function, which enabled it to infect rice cultivar Yashiromochi containing the corresponding resistant gene Pi-ta. These results suggested that genetic mutation caused by somatic HR is one of the mechanisms responsible for virulence diversity.     

Identification and characterization of a novel etiological agent of mango malformation disease in Mexico, Fusarium mexicanum sp. nov

The primary objective of this study was to characterize Fusarium spp. associated with the economically devastating mango malformation disease (MMD) in Mexico. In all, 142 Fusarium strains were isolated from symptomatic mango inflorescences and vegetative tissues in eight geographically diverse Mexican states from 2002 through 2007. Initially, all the Mexican isolates were screened for genetic diversity using appolymerase chain reaction and random amplified polymorphic DNA markers and were grouped into seven distinct genotypes. Based on results of these analyses, evolutionary relationships and species limits of the genetically diverse MMD-associated Fusarium spp. were investigated using multilocus DNA sequence data and phylogenetic species recognition. Maximum parsimony analyses of a five-locus data set comprising 5.8 kb of aligned DNA sequence data indicated that at least nine phylogenetically distinct Fusarium spp. within the Gibberella fujikuroi species complex are associated with MMD, including one species within the African clade (Fusarium pseudocircinatum), two species within the Asian clade (F. mangiferae and F. proliferatum), and at least six species within the American clade (F. sterilihyphosum and five undescribed Fusarium spp.). Molecular phylogenetic analyses indicate that a novel genealogically exclusive lineage within the American clade was the predominant MMD associate in Mexico. This new Fusarium sp. caused MMD and could be distinguished from all other known species morphologically by the production of mostly sterile, coiled hyphae which are typically associated with sporodochial conidiophores together with unbranched or sparsely branched aerial conidiophores. Koch's postulates were completed for isolates of the new species on nucellar seedlings of mango cv. Ataulfo. This pathogen is formally described herein as F. mexicanum.     

Molecular typing and antimicrobial resistance of Salmonella enterica subspecies enterica serovar Choleraesuis isolates from diseased pigs in Japan

Salmonella enterica serovar Choleraesuis (S. Choleraesuis) isolates derived from diseased pigs in Japan during 2001 and 2005 were analyzed for biotype, based on H(2)S production and dulcitol fermentation, pulsed-field gel electrophoresis (PFGE) profile, and antimicrobial resistance profile. S. Choleraesuis biotype Choleraesuis (biotype Choleraesuis) was classified into one genotype, while varietas Kunzendorf (var. Kunzendorf) was classified into two genotypes. The isolates of var. Kunzendorf belonging to one genotype were isolated in a limited area of Japan. Variation in the antimicrobial resistance pattern was observed in isolates of both biotypes Choleraesuis and var. Kunzendorf. We have also shown that the PFGE profile was associated with the biotype and isolation region of each isolate.     

Interaction between myostatin and extracellular matrix components

Myostatin, a member of the TGF-β superfamily, is a negative regulator of skeletal muscle mass. We have recently demonstrated that decorin binds to myostatin in vitro , and that immobilized decorin within the collagen matrix prevents myostatin-mediated inhibition of myoblast proliferation. However, little is known about other ECM molecules that bind to myostatin and modulate its activity. Thus, in the present study, we investigated the interaction of several other ECM molecules with myostatin. We here show that fibromodulin, fibronectin and laminin bind to myostatin in the presence of Zn²⁺ with a dissociation constant ( K_D ) of 10⁻¹⁰∼10⁻⁸ mol/L. Fibromodulin shows the highest affinity for myostatin among them. These results suggest that these ECM molecules may modulate myostatin activity like decorin does.     

Construction of a system for exploring mitotic homologous recombination in the genome of Pyricularia oryzae

To investigate mitotic homologous recombination (HR) in Pyricularia oryzae, we created an HR detection system. The system consists of two non-functional enhanced yellow fluorescent protein (YFP) and blasticidin S deaminase (BSD) fusion genes (YFP::BSD). If mitotic HR occurs between the two non-functional genes in the genome, restoration of the functional YFP::BSD gene can be expected. The expression of the functional YFP::BSD gene can be detected by both YFP fluorescence and resistance against BS. When the P. oryzae genome was transformed simultaneously with two non-functional genes, all six lines of transformants with both genes had some portion of their hyphae exhibiting YFP fluorescence and BS resistance during growth. Up to ca. 10 % of conidia harvested from the mycelium of each of the six lines had YFP fluorescence, suggesting that HR consistently occurs during mycelium growth. To determine whether and how the HR-mediated phenotypic changes occurred at the DNA level, we analyzed the genomic DNA of BS-resistant mycelia by PCR-RFLP and sequencing and were able to confirm the existence of a restored functional YFP::BSD gene and a non-functional recombinant gene. Collectively, these findings demonstrate that we established a successful HR detection system for P. oryzae, which can be used for other plant pathogens, and that mitotic HR actually occurs in P. oryzae and constitute the first experimental evidence for mitotic HR in a fungus.     

Characterization of spheres derived from canine mammary gland adenocarcinoma cell lines

There is increasing evidence for the presence of cancer stem cells in several solid tumors, and these cancer stem cells have a potential role in tumor initiation, aggression, and recurrence. The stem cell-like properties of spheres derived from canine mammary tumors remain largely elusive. We attempted to induce sphere formation using four cell lines of canine mammary adenocarcinoma, and characterized the spheres derived from a CHMp line in vitro and in vivo. The CHMp-derived spheres showed predominantly CD44⁺CD24⁻ population, higher expression of stem cell-related genes, such as CD133, Notch3 and MDR, and higher resistance to doxorubicin compared with the CHMp-derived adherent cells. Xenograft transplantations in nude mice demonstrated that only 1 × 10⁴ sphere cells were sufficient for tumor formation. Use of the sphere assay on these sphere-derived tumors showed that sphere-forming cells were present in the tumors, and were maintained in serial transplantation. We propose that spheres derived from canine mammary adenocarcinoma cell lines possess a potential characteristic of cancer stem cells. Spheres derived from canine mammary tumors could be a powerful tool with which to investigate novel therapeutic drugs and to elucidate the molecular and cellular mechanisms that underlie tumorigenesis.