Hyaluronidase is not essential for the lethality of Erysipelothrix rhusiopathiae infection in mice     

Shimoji Y  Asato H  Sekizaki T  Mori Y  Yokomizo Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2002,64(2):173-176

To investigate the role of hyaluronidase in the pathogenicity of Erysipelothrix rhusiopathiae, transposon Tn916 was transferred from Enterococcus faecalis CG110 to a virulent strain of E. rhusiopathiae, and hyaluronidase-deficient mutants were isolated. A virulence assay in the mice showed that of the seven hyaluronidase-deficient mutants tested, six mutants were avirulent, but that one mutant, designated AST121, was as virulent as its parental strain. Western immunoblotting with a monoclonal antibody specific to the capsule, a major virulence factor of the organism, revealed that all of the avirulent mutants had lost the capsular antigen, whereas the mutant AST121 did not. These results suggest that the lack of virulence of the six hyaluronidase-negative mutants could be due to a loss of the capsule and that hyaluronidase does not contribute to the lethality of E. rhusiopathiae infection in mice.  相似文献   

Successful treatment of two dogs with allergic dermatitis by anti-allergic peptides (MS-antigen)     

Park SJ  Yoshida N  Nishifuji K  Sekiguchi M  Momoi Y  Fukada T  Iwasaki T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2002,64(1):63-65

The effects of non-specific immunotherapy with anti-allergic peptides extracted from the urine of human allergic patients (MS-antigen), in two dogs with allergic dermatitis (AD) have been described. Clinically, severe pruritus accompanied by secondary bacterial pyoderma did not respond to conventional therapy with systemic antibiotics. The first clinical change appeared as a significant reduction in pruritus within 3 months, around the time of the 15th injection in both cases. The clinical condition was stabilized after 5 months, allowing the gradual withdrawal of concurrent therapies and an increase of injection intervals. The correlation between the results of intradermal skin tests before and after treatment and the improvement of clinical signs was not obvious.  相似文献   

A 10-year survey of antimicrobial susceptibility of streptococcus suis isolates from swine in Japan   总被引：7，自引：0，他引：7  

Kataoka Y  Yoshida T  Sawada T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2000,62(10):1053-1057

A number of 689 Streptococcus suis isolates collected nationwide from diseased and healthy pigs from 1987 to 1996 were surveyed for antibiotic susceptibilities to 11 drugs. No isolates resistant to amoxicillin, chloramphenicol, and sulfamethoxazole/trimethoprim were found. Isolates were highly susceptible to penicillins (penicillin G, ampicillin, and amoxicillin) except cloxacillin. They were not susceptible to tetracycline, streptomycin, and kanamaycin (MIC90 50 microg/ml, > or = 100 microg/ml, and > or = 100 microg/ml, respectively). Multiple-resistant isolates (> or = 3 antimicrobial agents) were found in 20.3% of all isolates tested.  相似文献   

Analysis of the gacS-gacA regulatory genes of spontaneous mutants of Pseudomonas fluorescens biocontrol strain PfG32R     

W. Gusti Ngurah Alit-Susanta  Yuichi Takikawa 《Journal of General Plant Pathology》2006,72(3):159-167

Pseudomonas fluorescens strain PfG32R, a potential biocontrol agent against soilborne pathogens, frequently loses its antifungal activity and ability to produce enzymes. To characterize genetically the instability of these bacterial functions, we analyzed gacS and gacA genes of PfG32R and three spontaneous mutants of PfG32R (NR1, NR9, and ASW6), which had lost their ability to produce proteases and antifungal activities. The gacS and gacA sequences of PfG32R had 77%–89% and 78%–87% homology, respectively, with several known gacS and gacA homologues. All three spontaneous mutants were subjected to complementation analysis. Introduction of clones containing an intact gacS of PfG32R and another P. fluorescens strain Pf-5 as well as strain tea632 of P. syringae pv. theae complemented all three mutants restoring protease and antifungal activities, indicating a mutation in gacS. In sequencing analysis, the mutants had a deletion or change in amino acids in the conserved sensor kinase domains of GacS. The three mutants maintained both their antibacterial activity against Ralstonia solanacearum and Clavibacter michiganensis ssp. michiganensis and siderophore production, indicating that they are not controlled by the GacS/GacA system. The sequences reported in this article have been deposited in the DDBJ database under accession numbers AB219364 and AB219365.  相似文献   

Fungal cell wall degrading enzyme-producing bacterium enhances the biocontrol efficacy of antibiotic-producing bacterium against cabbage yellows     

Someya  N.  Tsuchiya  K.  Yoshida  T.  Noguchi  M. T.  Akutsu  K.  Sawada  H. 《植物病害和植物保护杂志》2007,114(3):108-112

Journal of Plant Diseases and Protection - The antagonistic rhizobacterium, Pseudomonas fluorescens strain LRB3W1, controls cabbage Fusarium yellows caused by Fusarium oxysporum f. sp. conglutinans...  相似文献   

Developmental changes in pituitary–thyroid axis, and formation of gonads in leptocephali and glass eels of Anguilla spp.     

Yuichi Ozaki  Hiromi Okumura  Yukinori Kazeto  Toshitaka Ikeuchi  Shigeho Ijiri  Masaki Nagae  Shinji Adachi and  Kohei Yamauchi 《Fisheries Science》2000,66(6):1115-1122

SUMMARY: Pituitary, thyroid gland and gonads in leptocephali of Japanese eel Anguilla japonica (19.8–32.6 mm in total length), A. obscura (45.0 mm), and A. bicolor pacifica (49.5 mm) and those in glass eels of the Japanese eel were histologically and immunohistochemically examined in order to observe the developmental changes of these endocrine organs in the Anguillidae. The pituitary, consisting of adenohypophysis and neurohypophysis in Japanese eel leptocephali over 22.5 mm, did not contain thyroid stimulating hormone (TSH) immunoreactive cells. Such cells were, however, detectable in the more developed pituitaries of leptocephali of A. obscura and A. bicolor pacifica and in those of glass eels. Conversely, thyroxine (T₄)-immunoreactive thyroid follicles could be detected in all specimens, both leptocephalic and glass eel. Only in glass eels, gonads were found in the body cavity, and these gonads harbored one or two primordial germ cells (PGC) per cross-section. Our results indicate that thyroid hormones (TH) production started prior to TSH production, and that TSH and TH are both secreted during the metamorphosis from leptocephalus to glass eel. Therefore, it is plausible that the TSH–TH axis is involved in the metamorphosis from leptocephalus to glass eel, but not in the early growth from preleptocephalus to leptocephalus.  相似文献   

Quantitative structure-activity relationships of herbicidal N′-substituted phenyl-N-methoxy-N-methylureas     

Ichiki Takemoto  Ryo Yoshida  Seizo Sumida  Katsuzo Kamoshita 《Pesticide biochemistry and physiology》1985,23(3):341-348

Relationships between three types of herbicidal activity of N′-substituted phenyl-N-methoxy-N-methylureas and substitution at the benzene ring were analyzed by the Hansch-Fujita method. First, the Hill inhibitory activity was correlated with electronic (σ) as well as hydrophobic (π) substituent constants. The existence of an optimum value of hydrophobicity for substituents was suggested to reach the target site of action. Second, bliaching activity observed for the 3-substituted but not for 4-substituted compounds was correlated with π, σ, and steric substituent constant, E_s. Third, the postemergent herbicidal activity was shown to correlate linearly with the Hill inhibitory activity, pI₅₀, and hydrophobic parameter, π.  相似文献   

A method for isolation of milled-wood lignin involving solvent swelling prior to enzyme treatment     

J. -Y. Chen  Yuichi Shimizu  Mitsuo Takai  Jusuke Hayashi 《Wood Science and Technology》1995,29(4):295-306

Summary A new lignin isolation method has been developed. Wood and pulp were subjected to ball milling, swelled in an organic solvent, and then treated with a cellulase. The enzyme digestion time could be shortened to 1 day with this method. The lignin obtained has been named Swelled Enzyme Lignin (SEL). Swelling and enzyme digestion conditions and their effects on lignins were investigated. The SEL's from wood could be directly washed with water, while those from pulp had to be washed with aqueous acetic acid because they were water soluble. The purification of crude SEL's was accomplished by extracting them with dioxane-water, and then precipitating and washing with ethyl ether. Lignin yields were 24–67% based on the total amount of lignin present. The characteristics of the SEL's were further investigated by gel-permeation chromatography (GPC), infrared and ¹³C nuclear magnetic resonance (NMR) spectroscopy.Symbols SUKP Softwood Unbleached Kraft Pulp - BUKP Birch Unbleached Kraft Pulp - TD Todomatsu (Abies sachalinensis) wood - MWL Milled Wood Lignin - MWLS (BK, TD) Milled Wood Lignin of SUKP (BUKP, TD) - SEL-C Swelled Enzyme Lignin (crude) - SELS-C SEL-C of SUKP, other materials named in the same way - SELS-90 SEL-C of SUKP and extracted with 90% dioxane-water - SELS-96 SEL-C of SUKP and extracted with 96% dioxane-water, other materials named in the same way  相似文献   

Generation and alteration of norlignans in a transition zone during the drying of a Cryptomeria japonica log     

Kazumasa Yoshida  Mitsuru Nishiguchi  Shojiro Hishiyama  Atsushi Kato  Koetsu Takahashi 《Journal of Wood Science》2006,52(4):372-375

Sugi (Cryptomeria japonica D. Don) produces secondary metabolite norlignans in xylem. Several norlignans are involved in the coloration of heartwood and defense of sapwood against microbial invasion. Their biosynthetic process should be well understood so that their properties can be exploited to improve the quality and utility of C. japonica wood. Unfortunately, information on the norlignan biosynthesis is limited because norlignans are mainly synthesized in a particular season in the transition zone (TZ) along with the heartwood formation, and is difficult to study. Although the generation of two norlignans of C. japonica, agatharesinol and (E)-hinokiresinol, has been reported, systems for producing other norlignans are not yet known. To establish a novel norlignan generating system, we examined the changes occurring in norlignans in a TZ during the process of drying a C. japonica log. On the day of felling, the TZ contained agatharesinol and (E)-hinokiresinol, which increased until they reached a maximum on day 40 after felling. Sequirin-C appeared on day 40 and increased to day 70. The generation of sequirin-C in the TZ can be used to investigate the biosynthetic process of heartwood norlignans. This study describes for the first time the changes that occur in the composition of norlignan during the drying of the TZ.  相似文献   

Allometric model of the height–diameter curve for even-aged pure stands of Japanese cedar (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>)     

Akio?InoueEmail author  Shigejiro?Yoshida 《Journal of Forest Research》2004,9(4):325-331

We derived an allometric model of the height–diameter curve for even-aged pure stands, which was a modification of the earlier model proposed by Inoue (2000a). An individual-dependent allometric equation was used as the height–diameter curve. Using the discriminant analysis method, all trees composed of a stand were stratified into upper and lower trees. It was assumed that both relationships between mean tree height H _m and upper tree height H _u and between mean DBH D _m and mean DBH of upper trees D _u could be described by the time-dependent allometric power equations. The height–diameter curve showed an average relationship between tree height and DBH of a given stand at a given time, and hence it could be assumed that the height–diameter curve contained two points (D _m , H _m ) and (D _u , H _u ). With these assumptions, we derived an allometirc model of height–diameter curve, which allowed the coefficients of the curve to be estimated from mean tree height and mean DBH. The proposed model was fitted to Japanese cedar (Cryptomeria japonica D. Don) data. The error ratio of the allometric model ranged from 2.254% to 13.412% (mean = 6.785%), which was significantly smaller than that of the earlier model. When the error of mean tree height was ±1.0 m or less, the effect of the error of mean tree height on the error ratio was comparatively small. This suggested that the error of ±1.0 m in mean tree height could be accepted in the estimation of height–diameter curve using the allometric model. These features enable us to combine the allometric model with Hirata’s vertical angle-count sampling or growth models. In conclusion, the allometric model would be one of the most practical and convenient approaches for estimating the height–diameter relationship of even-aged pure stands.  相似文献