Anti-influenza A virus activities of mannan-binding lectins and bovine conglutinin

Mannan-binding lectin (MBL) and bovine conglutinin (BKg) belong to the collectin family, which is involved in first-line host defense against various infectious agents. We have previously reported that human MBL inhibited type A influenza viral hemagglutination, infection and spreading to adjacent cells without complement activation. In this study, we investigated the direct antiviral activities of bovine MBL, rabbit MBL and BKg. All collectins used in this study inhibited viral infectivity and hemagglutination at concentrations of 0.02-0.3 microg/ml. They also demonstrated inhibitory activity against viral spreading. Like human MBL, bovine MBL and BKg showed antiviral activities at their physiological concentrations. These results suggest that mammalian MBLs and BKg may inhibit the spread of influenza A virus through the bloodstream.     

An Isolate of Alternaria alternata That Is Pathogenic to Both Tangerines and Rough Lemon and Produces Two Host-Selective Toxins, ACT- and ACR-Toxins

ABSTRACT Two different pathotypes of Alternaria alternata cause Alternaria brown spot of tangerines and Alternaria leaf spot of rough lemon. The former produces the host-selective ACT-toxin and the latter produces ACR-toxin. Both pathogens induce similar symptoms on leaves or young fruits of their respective hosts, but the host ranges of these pathogens are distinct and one pathogen can be easily distinguished from another by comparing host ranges. We isolated strain BC3-5-1-OS2A from a leaf spot on rough lemon in Florida, and this isolate is pathogenic on both cv. Iyokan tangor and rough lemon and also produces both ACT-toxin and ACR-toxin. Isolate BC3-5-1-OS2A carries both genomic regions, one of which was known only to be present in ACT-toxin producers and the other was known to exist only in ACR-toxin producers. Each of the genomic regions is present on distinct small chromosomes, one of 1.05 Mb and the other of 2.0 Mb. Alternaria species have no known sexual or parasexual cycle in nature and populations of A. alternata on citrus are clonal. Therefore, the ability to produce both toxins was not likely acquired through meiotic or mitotic recombination. We hypothesize that a dispensable chromosome carrying the gene cluster controlling biosynthesis of one of the host-selective toxins was transferred horizontally and rearranged by duplication or translocation in another isolate of the fungus carrying genes for biosynthesis of the other host-selective toxin.     

Inhibitory effects of edible marine algae extracts on degranulation of RBL-2H3 cells and mouse eosinophils

Inhibitory effects on degranulation of rat basophilic leukemia (RBL-2H3) cells and mouse eosinophils by marine algae extracts were examined. More than 50% of the degranulation of RBL-2H3 cells was inhibited by water extracts of Ecklonia cava and Chrysymenia wrightii at a concentration of 100 μg/mL. More than 50% of the degranulation of RBL-2H3 cells was inhibited by methanol extracts of Petalonia binghamiae, Scytosiphon lomentaria, Undaria pinnatifida, Porphyra dentata, Codium fragile and Ulva japonica at a concentration of 200 μg/mL. Most inhibitory substances in the methanol extracts were partitioned into ethyl acetate and hexane layers. The ethyl acetate-partitioned layer of methanol extract of Petalonia binghamiae had higher inhibitory effects than the hexane-partitioned layer on the degranulation of RBL-2H3 cells. By contrast, the hexanepartitioned layer of the same extract had a higher inhibitory effect than the ethyl acetate-partitioned layer on the degranulation of mouse eosinophils. The ethyl acetate-partitioned layer of methanol extract of Petalonia binghamiae was further separated into eight fractions by silica gel column chromatography. Most inhibited the degranulation of RBL-2H3 cells, but not that of mouse eosinophils significantly. These results suggest methanol extract of Petalonia binghamiae contains materials that inhibit the degranulation of basophils and eosinophils differentially.     

Serological survey of antibodies to four pathogens in wild boars in Nagano Prefecture,Japan

Wild boars (Sus scrofa) captured or found dead in Nagano Prefecture were surveyed for antibodies to Aujeszky’s disease virus (ADV), Erysipelothrix rhusiopathiae, porcine reproductive and respiratory syndrome virus (PRRSV), and Toxoplasma gondii. While all 168 samples tested were negative for anti-ADV antibodies and all 140 samples tested were negative for anti-PRRSV antibodies, all 190 samples tested were positive for anti-E. rhusiopathiae antibodies and 12 of 180 samples were positive for anti-toxoplasma antibodies. These results suggest that since E. rhusiopathiae and T. gondii cause zoonotic diseases, in addition to wild boars being a potential source of infection for domestic pigs, caution should be taken when handling wild boars or eating wild boar meat because of the possibility of human infection.     

Antioxidative and antiradical activities of <Emphasis Type="Italic">Eucalyptus camaldulensis</Emphasis> leaf oils from Thailand

The leaf essential oils (six samples) from three clones of Eucalyptus camaldulensis Dehnh. were characterized by gas chromatography-mass spectrometry. Radical scavenging and antioxidant properties were investigated by the 1,1-diphenyl-2-picylhydrazyl (DPPH) assay and the β-carotene bleaching test. It was found that the whole essential oil and its fractions had significant antioxidant effects when they were tested by each method. In the DPPH assay, the E. camaldulensis leaf oils showed IC₅₀ inhibitory concentrations in the range of 1.75–12.62 mg/ml. In the β-carotene bleaching test, the IC₅₀ valued were in the range of 14.30–118.55 μg/ml. Part of this report was presented at the 18th meeting of the Chugoku-Shikoku Branch of the Japan Wood Research Society, November 2006     

Locating and identifying splits and holes on sugi by the laser displacement sensor

The split and the hole are two common defects on sugi (Cryptomeria japonica D.Don). They have a common feature in that they are associated with surface irregularities. We have developed a laser scanning system to detect the splits and the holes based on their thickness, which correlates spatially with the profile information. The displacements measured by the laser sensor were converted to pixel values to generate the displacement profile image. Both the splits and the holes manifested well in the image. A dedicated image-processing program written in Visual Basic has been developed. The defects regions were accurately located by the image processing. To identify the defects, eight recognition rules based on four features have been utilized. Furthermore, a method based on the pixel model was proposed to compute the area of the defect. The results indicated that the defects could be identified correctly, and the areas could be computed accurately using the pixels model.     

Evaluation of surface smoothness by a laser displacement sensor II: comparison of lateral effect photodiode and multielement array

Development of accurate surface assessment technology is of vital interest to modern wood industries. In this experiment we investigated new and fast noncontacting sensors to determine their usefulness for wood surface evaluation and to verify their accuracy. Two types of laser displacement sensors [equipped with a position sensitive detector (PSD) and a charge coupled device (CCD) detector] are compared with a conventional stylus and with theoretical profiles. Hornbeam workpieces with triangular profiles of differing slope and height were used for the evaluation. The results show that resolution of both sensors decreases as the height of the profile decreases. The error ratio of the laser-scanned profiles changes as a function of profile height, in the range 5%–33%. The CCD method is superior for accurate surface roughness evaluation, although the PSD approach can still be used for monitoring the error of form in most applications.Parts of this work were presented at the 50th Annual Meeting of the Japan Wood Research Society, Kyoto, April 2000 and at the 51st Annual Meeting of the Japan Wood Research Society, Tokyo, April 2001     

Proliferation of kuchijirosho causative agent in a fugu-derived cell line

Kuchijirosho is a fatal disease of commercially cultured fugu, Takifugu rubripes. The transmissible nature of kuchijirosho strongly suggests that an infectious pathogen is the causative agent. Because it is filtrable, the agent is thought to be a virus; however, it has not yet been identified. The lack of a permissive cell line for the putative kuchijirosho-causing agent (KCA) has hindered research on the identification of this pathogen. We inoculated brain extract prepared from kuchijirosho-affected fugu onto an established fugu cell line, fugu eye, and observed that cytopathic effect appeared 7 days after inoculation. Injection of the culture medium of infected fugu eye cells into fugu resulted in the onset of kuchijirosho, indicating that fugu eye cells are able to proliferate KCA. An infectious fraction separated by sodium iottalamate density gradient centrifugation showed a density of 1.15 g mL(-1) equivalent to that of KCA derived from affected fugu brain. To determine whether the genome of KCA is RNA or DNA based, nucleotide synthesis inhibitors were applied to inoculated fugu eye cell line to influence the production of KCA. 5-Fluorouracil but not IUdR showed a concentration-dependent inhibition of KCA yield. These results suggest that KCA is an RNA virus.