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1.
Monokaryotic strains of Helicobasidium mompa were used as vectors of a mycovirus between various H. mompa isolates to examine the transmissibility of one of the mycoviruses, totivirus (HmTV1–17 virus) in the hypovirulent isolate V17 of H. mompa. The isolates that acquired HmTV1–17 virus were also examined for any alteration in the virulence. Twelve dikaryotic isolates of H. mompa, belonging to 11 mycelial compatibility groups (MCGs) and being mycelially incompatible with isolate V17, were used as recipients of HmTV1–17 virus. Two monokaryotic isolates that were mycelially incompatible with isolate V17 and all of the recipients were also used as vectors of HmTV1-17 virus between isolate V17 and the recipients. When isolate V17 and recipients were directly paired on plate media, HmTV1-17 virus was transmitted from isolate V17 into 2 of the 12 recipients (i.e., 2 of the 11 MCGs). Two monokaryotic strains were paired with isolate V17, and the monokaryotic strains that acquired HmTV1-17 virus were then used as new virus donors. When the monokaryotic strains containing HmTV1-17 virus were paired with the 12 recipients, HmTV1-17 virus was transmitted into 7 of the 12 recipients from the monokaryotic strains (i.e., 7 of 11 MCGs). Based on these results, we concluded that monokaryotic strains could act as vectors to transmit HmTV1-17 virus into H. mompa isolates. When four of the H. mompa isolates that acquired HmTV1-17 virus were used to inoculate apple rootstock Malus prunifolia, the virulence of all of the isolates was attenuated from that of their parental isolates. Moreover, because the DNA fingerprints of the fungal isolates that acquired HmTV1-17 virus were the same as those of their parental isolates, the infection with HmTV1-17 virus is considered the cause of virulence attenuation of H. mompa.  相似文献   
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The aims of this study were to develop a new real-time quantitative PCR (QPCR) assay based on IS900 for detection and quantification of Mycobacterium avium subsp. paratuberculosis (MAP) DNA in faeces, and to use this to detect infected sheep. Both the C and S strains of MAP were detected by the QPCR assay, and no cross reactions were detected with 51 other species of mycobacteria including 10 which contained IS900-like sequences. One copy of IS900 fragment cloned into plasmid pCR2.1 and 1 fg of MAP genomic DNA were consistently detected, while in spiked faecal samples the detection limit was 10 viable MAP per gram of ovine faeces. A total of 506 individual ovine faecal samples and 27 pooled ovine faecal samples with known culture results were tested. The QPCR assay detected 68 of 69 BACTEC culture positive individual faeces and there was a strong relation between time to detection in culture and DNA quantity measured by QPCR (r= -0.70). In pooled faecal samples, QPCR also agreed with culture (kappa=0.59). MAP DNA was detected from some culture negative faecal samples from sheep exposed to MAP, suggesting that the QPCR has very high analytical sensitivity for MAP in faecal samples and detects non-viable MAP in ovine faeces. None of the faecal samples from 176 sheep that were not exposed to MAP were positive in QPCR. This is the first report of a direct faecal QPCR assay that has similar sensitivity to a gold standard radiometric culture assay.  相似文献   
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Saxitoxin and its analogues, paralytic shellfish toxins (PSTs), are potent and specific voltage-gated sodium channel blockers. These toxins are produced by some species of freshwater cyanobacteria and marine dinoflagellates. We previously identified several biosynthetic intermediates of PSTs, as well as new analogues, from such organisms and proposed the biosynthetic and metabolic pathways of PSTs. In this study, 12β-deoxygonyautoxin 5 (12α-gonyautoxinol 5 = gonyautoxin 5-12(R)-ol) was identified in the freshwater cyanobacterium, Dolichospermum circinale (TA04), and 12β-deoxysaxitoxin (12α-saxitoxinol = saxitoxin-12(R)-ol) was identified in the same cyanobacterium and in the marine dinoflagellate Alexandrium pacificum (Group IV) (120518KureAC) for the first time from natural sources. The authentic standards of these compounds and 12α-deoxygonyautoxin 5 (12β-gonyautoxinol 5 = gonyautoxin 5-12(S)-ol) were prepared by chemical derivatization from the major PSTs, C1/C2, produced in D. circinale (TA04). These standards were used to identify the deoxy analogues by comparing the retention times and MS/MS spectra using high-resolution LC-MS/MS. Biosynthetic or metabolic pathways for these analogues have also been proposed based on their structures. The identification of these compounds supports the α-oriented stereoselective oxidation at C12 in the biosynthetic pathway towards PSTs.  相似文献   
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Parasporal inclusion proteins produced by Bacillus thuringiensis strain A1470 exhibit strong cytotoxicity against human leukemic T cells when activated by protease treatment. One of the cytotoxic proteins was separated by anion exchange chromatography and gel filtration chromatography and designated Cry45Aa. Its gene was then expressed in recombinant Escherichia coli, in which the Cry45Aa precursor was accumulated in an inclusion body. It was solubilized in sodium carbonate buffer and processed with proteinase K, and cytotoxic activities of the protein against various mammalian cell lines were evaluated using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide assay. The protein exhibited high cytotoxic activity against CACO-2, Sawano, MOLT-4, TCS, and HL60 cells and moderate activity against U-937 DE-4, PC12, and HepG2 cells. On the other hand, the EC50 values against Jurkat, K562, HeLa, A549, Vero, COS-7, NIH3T3, CHO, and four normal tissue cells (human primary hepatocyte cells, UtSMC, MRC-5, and normal T cells) were >2 microg/mL.  相似文献   
6.
Babesia rodhaini is a rodent hemoparasite closely related to B. microti, the major causative agent of human babesiosis. We tested the infectivity of B. rodhaini for human erythrocytes by using the SCID mouse model in which the circulating erythrocytes were replaced with those of humans. Initially, parasites grew very poorly in the mouse model, but a variant capable of propagating in human erythrocytes emerged after an adaptation period of three weeks. In an attempt to identify parasite proteins involved in the alteration of host cell preference, an expression cDNA library of B. rodhaini was constructed and screened with immune mouse sera. Although we were able to obtain three merozoite surface protein (MSP) genes, sequences of these genes from both the parental strain and human erythrocyte-adapted substrain were identical. Our results suggest that B. rodhaini has potential ability to infect human erythrocytes, but development of this ability may not be brought about by an amino acid change in MSPs.  相似文献   
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Background – Filaggrin (FLG) is a key protein for skin barrier formation and hydration of the stratum corneum. In humans, a strong association between FLG gene mutations and atopic dermatitis has been reported. Although similar pathogenesis and clinical manifestation have been argued in canine atopic dermatitis, our understanding of canine FLG is limited. Hypothesis/Objectives – The aim of this study was to determine the structure of the canine FLG gene and to raise anti‐dog FLG antibodies, which will be useful to detect FLG protein in dog skin. Methods – The structure of the canine FLG gene was determined by analysing the publicly available canine genome DNA sequence. Polyclonal anti‐dog FLG antibodies were raised based on the canine FLG sequence analysis and used for defining the FLG expression pattern in dog skin by western blotting and immunohistochemistry. Results – Genomic DNA sequence analysis revealed that canine FLG contained four units of repeated sequences corresponding to FLG monomer protein. Western blots probed with anti‐dog FLG monomer detected two bands at 59 and 54 kDa, which were estimated sizes. The results of immunohistochemistry showed that canine FLG was expressed in the stratum granulosum of the epidermis as a granular staining pattern in the cytoplasmic region. Conclusions and clinical importance – This study revealed the unique gene structure of canine FLG that results in production of FLG monomers larger than those of humans or mice. The anti‐dog FLG antibodies raised in this study identified FLG in dog skin. These antibodies will enable us to screen FLG‐deficient dogs with canine atopic dermatitis or ichthyosis.  相似文献   
10.
The effect of organic amendment on the resistance and resilience of the organic matter decomposing activity was compared between soils amended with compost and with chemical fertilizers. The impact of metam sodium disinfection on cellulose-decomposing activity and on the number of nematodes in three types of soils was periodically measured. In an andosol, cellulose-decomposing activity was significantly suppressed by soil disinfection only in the chemically fertilized soil (CF-soil) and not in the soils to which cow manure compost and okara (the residue in tofu production)/coffee compost was added. In a brown lowland soil, cellulose-decomposing activity was significantly suppressed by soil disinfection in the CF-soil, but not in the soils to which higher amounts of cow manure compost and pig manure compost had been added. In a red-yellow soil, cellulose-decomposing activity was significantly suppressed by soil disinfection in all soils, but its resilience was higher in the soils to which cow manure compost or coffee compost was added compared with the CF-soil. Total numbers of nematodes were markedly decreased by soil disinfection in all soils. These results may suggest that the resistance and resilience of cellulose-decomposing activity against soil disinfection were enhanced by organic amendments, while disinfection had fatal effects on soil nematodes. In most of the organically amended soils, the mean weight diameters of aggregates were larger compared with the CF-soils, suggesting that highly structured soil pore networks may provide shelters for the soil microbes responsible for cellulose decomposition against disinfection. This hypothesis was supported by the result that the resistance of cellulose-decomposing activity against soil disinfection decreased when the soil structure was destroyed by grinding in a mortal and pestle.  相似文献   
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