Isolation of exfoliative toxin from Staphylococcus intermedius and its local toxicity in dogs

A rounding effect was demonstrated in cultured cells inoculated with the culture filtrates (CFs) of 60 strains of Staphylococcus intermedius derived from dogs affected with pyoderma. Exfoliative toxin (ET)-like toxin (ETLT) was isolated from the CF of S. intermedius strain D-52, which exhibited strong rounding activity and then was purified by gel filtration on a Sephadex G-75 column, and by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The ETLT caused exfoliation in 1-day-old chickens, suckling Syrian hamsters, and dogs, but not in suckling mice. The ETLT was serologically different from exfoliative toxin A (ETA), exfoliative toxin B (ETB), exfoliative toxin C (ETC), S. hyicus exfoliative toxin A (SHETA), and SHETB, as shown by Western blot analysis. The molecular weight of the ETLT was estimated at 30 kDa by SDS-PAGE. In the present study, we propose the ETLT was a novel type of ET, S. intermedius exfoliative toxin (SIET).     

Cloning of the gene coding for Staphylococcus intermedius exfoliative toxin and its expression in Escherichia coli

An exfoliative toxin (SIET)-producing strain (D-52) of Staphylococcus intermedius derived from canine pyoderma did not possess large plasmids. Therefore, the gene coding for SIET was considered to be located on the chromosomal DNA. The SIET gene was cloned from the chromosomal DNA of S. intermedius and was expressed in Escherichia coli. The nucleotide sequence of the SIET gene consists of a coding region of 990 bp specifying a polypeptide of 330 amino acid residues, which included a putative 42-residue signal sequence.     

Possible vector insect of mulberry dwarf phytoplasma, Tautoneura mori Matsumura

Mulberry dwarf (MD) phytoplasma was surveyed for its presence in presumably nonvector insects (two species of leafhoppers, thrips, and spider mites) collected from MD-diseased trees. MD phytoplasma was found in all species by nested polymerase chain reaction using specific primers for the 16Sr I-group phytoplasma. By electron microscopy, MD phytoplasma was observed in the salivary glands of the leafhopper Tautoneura mori Matsumura. In addition, the vector ability of T. mori was verified through bioassay; 25% of seedlings inoculated with infective leafhoppers had MD symptoms, suggesting that T. mori may act as a vector of MD phytoplasma in fields in some cases.     

Plectosporium blight of pumpkin and ranunculus caused by Plectosporium tabacinum

Based on inoculation experiments and morphological studies on the pathogenic isolates of Plectosporium spp., Microdochium blight (Hakuhan-byo in Japanese) of pumpkin (Cucurbita maxima Duch.) occurring in Japan was reconfirmed to be caused by Plectosporium tabacinum, and seedling blight (Kabugare-byo in Japanese) of ranunculus (Ranunculus asiaticus L.) was demonstrated to be caused by P. tabacinum. Both diseases are renamed Plectosporium blight in this article. Some isolates of the fungus appeared to have host specificity, whereas the others had either weak or no pathogenicity to pumpkin and ranunculus.     

人体醛缩酶C cDNA的克隆及其在家蚕体内的表达(英文)

利用人体醛缩酶C cNDA的一对特异性引物A ld-5′(5′-ggatcccctcactcgtaccca-3′)和A ld-3′(5′g-gatcctcag-taggcatggtt-3′),从人脑cDNA文库中PCR扩增出人体醛缩酶C cDNA,并依次被克隆进克隆载体pCR2.1、转移载体pAcGP67B以及来源于AcNPV和BmNPV的杂交重组病毒HyNPV。通过对家蚕血液的SDS-PAGE电泳和酶活力测定,证明人体醛缩酶C cDNA在家蚕体内成功得到表达。     

Antimicrobial susceptibility of Escherichia coli isolates from dairy farms using organic versus conventional production methods

OBJECTIVE: To compare antimicrobial susceptibility patterns of Escherichia coli isolates cultured from fecal samples from cows and calves on dairy farms that used organic (ie, no or severely limited antimicrobial use) versus conventional production methods. DESIGN: Cross-sectional study. SAMPLE POPULATION: Fecal samples from 10 cows and 10 calves on each of 30 organic dairy farms and 30 neighboring conventional dairy farms in Wisconsin. PROCEDURE: E. coli isolates obtained from the fecal samples were tested for susceptibility to 17 antimicrobials by means of a microbroth dilution test. Prevalence of antimicrobial resistance was compared between organic and conventional dairy farms. RESULTS: E. coli was isolated from 1,121 (94%) fecal samples. Farm type (organic vs conventional) and animal age (cow vs calf) were significantly associated with odds that E. coli isolates would be resistant to various antimicrobials. After controlling for age, logistic regression analyses indicated that isolates from conventional dairy farms had significantly higher rates of resistance to ampicillin, streptomycin, kanamycin, gentamicin, chloramphenicol, tetracycline, and sulfamethoxazole than did isolates from organic dairy farms. However, no significant differences were detected for the 10 other antimicrobials that were tested. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that compared with isolates from conventional dairy farms, E. coli isolates from organic dairy herds have significantly lower prevalences of resistance to 7 antimicrobials; however, prevalence of resistance was not significantly different for 10 other antimicrobials. Resistance was more common for isolates from calves than for isolates from adult dairy cows.     

Capsid Protein Genetic Analysis and Viral Spread to the Spinal Cord in Cats Experimentally Infected with Feline Calicivirus (FCV)

We investigated primitively the molecular basis of the neural spread of a feline calcivirus isolate (FCV-S) from the spinal cord of a cat that died after manifesting excitation. Experimental infections of cats with three clones from parent virus isolate FCV-S, isolated based on plaque size, were performed, and virus recovery from the spinal cord and the nucleotide and predicted amino acid sequences of the viral capsid protein region (ORF2) were compared. In the experimental infection with the one-time cloned virus (C1L1) isolated from a large plaque, the C1L1 was recovered from the spinal cord. In contrast, seven-times cloned C6L7 (from large plaque) and five-times cloned C5S2 (isolated from small plaque) were not recovered from the spinal cord. Genetic analysis of the capsid protein gene of the three viral clones revealed that four bases were different and two amino acids were different at positions 34 (Val in C6L7 and Ala in C1L1 and C5S2) and 46 (Leu in C6L7 and Pro in C1L1 and C5S2) between C6L7 (with large plaque) and C5S2 (with small plaque). The amino acid at position 434 of C1L1 was different from those of C6L7 and C5S2 (Gly in C1L1, D (Asp) in C6L7 and C5S2). From these results, the plaque size seemed not to be related to the spread of virus to the spinal cord. Clone C1L1, which spread to the spinal cord, had a difference of one amino acid from the other two clones, which may be related to the ability to spread to the spinal cord.     

Serological evidence of infection of Anaplasma and Ehrlichia in domestic animals in Xinjiang Uygur Autonomous Region area, China

Serological methods were utilized to detect Anaplasma and Ehrlichia infection in domestic animals in Xinjiang Uygur Autonomous Region, China. By using an indirect immunofluorescence assay (IFA), antibodies that reacted with Anaplasmaphagocytophilum and Ehrlichiachaffeensis were detected mainly in ruminants kept on pastureland in Altai, Ili and Kashgar area. Antibody titers up to 1:320 were recorded. These results indicate that ruminants kept in these areas may be infected with some species of Anaplasma and Ehrlichia.     

Characterization of methicillin-resistant Staphylococcus aureus isolated from retail raw chicken meat in Japan

Two isolates of mecA-positive methicillin-resistant Staphylococcus aureus (MRSA) from retail raw chicken meat were characterized by phenotypic and genotypic methods. One isolate showed the human biovar, coagulase type III, phage group I * III, the lack of production of enterotoxins and TSST-1, and resistance to PCG/ABPC/EM/GM/KM. The other isolate showed the human biovar, coagulase type III, phage group III, production of enterotoxin C and TSST-1, and resistance to PCG/ABPC/CEZ. The biotyping results indicate that the two isolates showed characteristics of human S. aureus. They also harbored SCCmec type IV, which has prevalently been found in community-acquired MRSA isolates. This paper is the first publication regarding MRSA isolates from raw chicken meat in Japan.