Two new variants of the Rhodococcus equi virulence plasmid, 90 kb type III and type IV, recovered from a foal in Japan     

Takai S  Murata N  Kudo R  Narematsu N  Kakuda T  Sasaki Y  Tsubaki S 《Veterinary microbiology》2001,80(4):373-381

Calves were vaccinated orally, subcutaneously or intraperitoneally with a smooth, plasmid-cured strain of Salmonella enterica serovar typhimurium, strain 81. Oral vaccination was not effective, as only 1/5 calves survived challenge with virulent S. typhimurium. Strain 81 was attenuated for calves, as only a slight rise in rectal temperatures was detected after vaccination. The organism was excreted by some calves in the faeces, but no signs of diarrhoea were observed after vaccination. After parenteral vaccination, strain 81 was able to reach the intestines, gastric associated lymphoid tissues and other internal lymphoid tissues and remained viable for up to 14 days in the bovine host. After oral challenge with a virulent strain, 9/10 vaccinated calves survived challenge as opposed to 4/10 control calves (p<0.5). Diarrhoea was present in all calves of the control groups, but in only 4/10 of the vaccinated calves. The clinical reactions of the vaccinated calves were milder than in the control calves, as the rises in rectal temperatures were lower, diarrhoea was less severe, and the challenge strain was present in fewer organs from vaccinated calves than control calves. This study showed that parenterally administered Salmonella vaccines can induce both mucosal and systemic immunity, and it is postulated that this capability of strain 81 is related to its colonisation of lymphoid tissues and other systemic and intestinal tissues. This study confirmed that plasmid-cured strains were attenuated in the bovine host and conferred significant protection after parenteral vaccination, but not oral vaccination.  相似文献   

A modified immunoperoxidase assay for detection of antibody porcine reproductive and respiratory syndrome (PRRS) virus in swine sera     

Takashima H  Takai K  Goto S 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1999,61(2):195-196

MARC-145 cell monolayers infected with PRRS virus were fixed in 3% neutral buffered formalin and embedded in paraffin. The sections were stained by avidin-biotin complex immunoperoxidase (ABC) method. Test sera were applied to sections as primary antibodies. The positive reactions were detected by ABC method and indirect immunofluorescent assay (IFA). There was good correlation between ABC and IFA, and the titers in ABC were higher than those in IFA. The present results indicate that the immunohistochemical staining is a useful test for the detection and quantitation of PRRS virus antibody in swine sera as well as IFA.  相似文献   

Immunohistochemical analysis of pseudorabies virus spread through neurons innervating the eyeball     

Hiromi Takahashi  Chieko Kai  Yasuhiro Yoshikawa  Kazuya Yamanouchi 《Comparative immunology, microbiology and infectious diseases》1995,18(4):275-281

Pseudorabies virus (PRV) was inoculated intraocularly into BALB/c mice, and the distribution pattern of cells positive for several neurotransmitters and viral antigens in the eyeball, trigeminal nerve ganglia, and superior cervical ganglia was examined immunohistochemically to clarify the neural route of the virus spread. In the eyeball, substance P (SP)- and calcitonin gene-related peptide (CGRP)-positive cells were detected in the ipsilateral iris and ciliary body, neuropeptide tyrosine (NPY)-positive cells were detected in the choloid membrane, and tyrosine hydroxylase (TH)-positive cells were detected in the ipsilateral inner nuclear layer of the retina; all these cells contained viral antigens. In the superior cervical ganglia, viral antigen-positive cells containing TH or NPY were found at bilateral sites. In the trigeminal nerve ganglia, viral antigen-positive cells containing SP or CGRP were found at bilateral sites. These findings indicated that the SP- and CGRP-positive ganglion cells of the trigeminal nerve ganglia innervating the iris or ciliary body, and the NPY-positive ganglion cells of the superior cervical ganglia innervating the iris, ciliary body, and choroid membrane served as the route for the virus spread. These findings also suggested that dopaminergic neurons, such as the TH-positive retinal cells and TH-positive ganglion cells of the superior cervical ganglia, served as the route for virus spread.  相似文献   

Cytotoxicity for porcine islet cells by complement of six animal species     

Itakura S  Kato H  Wang PC  Matsunaga A  Jitsukawa T  Edamura K  Ohgawara H  Mochizuki M  Nishimura R  Sasaki N 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2003,65(10):1107-1109

Complement-mediated cytotoxicity for porcine islet cells (PICs) was evaluated using sera of six animal species. Then soluble complement receptor type-1 (sCR1) as an anti-complement agent was added to those sera, and the changes in 50% hemolytic unit of complement serum (CH50) and cytotoxic effect of those sera on PICs were examined. All the sera except for that of pig showed cytotoxicity. However, the extent of toxicity was considerably different between species. In the rat and human serum, sCR1 significantly reduced CH50 and cytotoxicity, however in the dog serum, sCR1 had no suppressive effects. These results may suggest that complement contribute to humoral cytotoxicity for PICs as a main factor, and the compatibility of complement with PICs differs between animal species.  相似文献   

A serological survey of Rhodococcus equi infection in foals in central Italy: comparison of two antigens using an ELISA test     

Cuteri V  Takai S  Moscati L  Battistacci L  Pieramati C  Valente C 《Comparative immunology, microbiology and infectious diseases》2003,26(1):17-23

A serological survey of Rhodococcus equi infection was carried out on 602 blood samples collected from foals in central Italy. The assay was performed with an ELISA test using two different antigens prepared with reference strains of R. equi, ATCC 33071 and ATCC 6939. A positive reaction was obtained on 81 serum samples (13.45%) (OD > or = 0.3) using antigen ATCC 33071, and on 73 serum samples (12.12%) using antigen ATCC 6939. Although the frequency of the disease was not high, the serological positivity was about 13%. There was no statistically significant difference between males and females. The ELISA test using either Antigen 33071 or Antigen 6939 is a rapid and reliable tool for detecting antibodies against R. equi in foals.  相似文献   

Langerhans cells within the follicular epithelium and the intradermal sweat duct in equine insect hypersensitivity "Kasen"     

Kurotaki T  Narayama K  Arai Y  Arai S  Oyamada T  Yoshikawa H  Yoshikawa T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2002,64(6):539-541

Histopathologic and electron microscopic observations were given on Langerhans cells (LCs) within the follicular epithelium (FE) and intradermal sweat duct (ISD) of equine "Kasen". By light microscopy, LCs were present in the greatest numbers within the FE and ISD than within the epidermal layer and the normal skin, with an occasional formation of several aggregated foci. By electron microscopy, LCs within the FE and ISD widely extended their dendritic processes between the keratinocytes and contained Birbeck granules (Bgs), mitochondria, rough endoplasmic reticula and ribosomes in the cytoplasm. Numerous Type 2 LCs, with a number of Bgs and endocytosis, and Type 3 LCs, with multivesicular bodies and endosomes of various sizes, were recognized within the FE and ISD, although inactive Type 1 LCs, with a narrow and lucid cytoplasm, were rarely seen. LCs observed within the FE and ISD in the "Kasen" skin lesions might express the particular stage corresponded to recognize, intake and process the antigens which permeate them.  相似文献   

Detection of DNA restriction fragment polymorphisms in Streptococcus equi     

Takai S  Anzai T  Yashiro H  Ishii C  Tsubaki S  Wada R  Timoney JF 《The Veterinary record》2000,146(6):159-161

Large-restriction-fragment (LRF) polymorphisms in Streptococcus equi (S equi subspecies equi) were studied by pulsed-field gel electrophoresis. Five or six chromosomal fragments of between 194 and 915 kb were separated by digestion with the restriction endonuclease Notl. All 20 isolates of S equi, including 12 from independent Japanese outbreaks, four from independent American outbreaks, two from a single Irish outbreak, us vaccine strain F43, and type strain NCTC 9682 were successfully typed. Seven distinctive, reproducible and stable types were identified. The 12 Japanese isolates collected between 1992 and 1998 were of LRF type II suggesting that they were derived from the same source. The remaining eight isolates were of six types. The results indicate that LRF typing should be a useful technique for investigating the source and transmission of S equi.  相似文献   

Pathogenicity of Rhodococcus equi expressing a virulence-associated 20 kDa protein (VapB) in foals     

Takai S  Anzai T  Fujita Y  Akita O  Shoda M  Tsubaki S  Wada R 《Veterinary microbiology》2000,76(1):71-80

Rhodococcus equi strains of intermediate virulence (IMV) for mice possess a 20kDa protein designated Virulence Associated Protein B (VapB) and a virulence plasmid of 79-100kb, and can be recovered from the submaxillary lymph nodes of pigs. The pathogenicity of such R. equi strains for foals is unknown. In this study, two foals, 42 and 43 days of age, were infected intratracheally with 10(6) and 10(9) cells of R. equi IMV strain A5, respectively. The foal infected with 10(9) cells of strain A5 became clinically ill, with the onset of illness (pyrexia and depression) occurring 21 days after inoculation. R. equi was isolated from the feces and tracheal washings of the foal from 14 to 28 days after inoculation. The foal infected with 10(6) cells of A5 showed no clinical signs, and no R. equi was isolated from any of the samples of feces or tracheal washings during the 28 days of observation. Two foals of 45 and 50 days of age were infected with 10(5) or 10(6) of virulent R. equi ATCC 33701 having 15-17kDa surface proteins designated VapA. Both exhibited severe clinical signs (pyrexia, depression and anorexia) at 12 and 13 days after inoculation. Histopathological examination revealed that strain A5 caused focal granulomatous pneumonia in the foals. R. equi IMV strain A5 was isolated from lung lesions of both foals and from the contents of the intestinal tracts of the foal infected with 10(9) bacteria. These results suggest that IMV R. equi having VapB is less virulent than virulent R. equi having VapA in foals. This finding supports our previous results on the pathogenicities of R. equi strains having these virulence-associated antigens assessed by mouse pathogenicity tests.  相似文献   

Enzyme-linked immunosorbent assay for diagnosis of Corynebacterium (Rhodococcus) equi infection in foals   总被引：8，自引：0，他引：8  

S Takai  S Kawazu  S Tsubaki 《American journal of veterinary research》1985,46(10):2166-2170

An enzyme-linked immunosorbent assay (ELISA) was used to diagnose Corynebacterium (Rhodococcus) equi infection in foals. In tests done with different antigen-extraction procedures (sodium dodecyl sulfate, sodium deoxycholate, polyoxy-ethylene [9] p-tert-octylphenol, polyoxy-ethylene [9-10] p-tert-octylphenol, sonification, homogenization, and heat treatment at 121 C), Tween 20 was a satisfactory reactive antigen. Using hyperimmune rabbit sera or infected foal sera, we investigated the specificity and the sensitivity of the ELISA with the Tween 20 antigen of the different serotypes or of the isolates. Corynebacterium equi strain ATCC 6939 antigen had the best activity for detecting antibodies to C equi in foals. Sera from 218 healthy horses, 11 healthy foals, 17 healthy newborn foals, a foal with suspected C equi infection, and 5 infected foals were evaluated for antibodies to C equi, using ELISA. The optical density values of 206 healthy horses, 17 healthy newborn foals, and 9 healthy foals were less than 0.1. Infected foal sera, except from foal 3, and serum from a foal with suspected C equi infection had higher optical density values. Using ELISA, specific antibodies against C equi were detected in a naturally infected 6-week-old foal after the foal had a rapid increase in the number of bacteria in the feces and after the initial development of clinical signs of illness at 5 weeks of age. Therefore, ELISA was useful for the early diagnosis of C equi infection in foals.  相似文献   

Application of a modified rate equation to the acetylation of wood     

Kazuya?MinatoEmail author 《Journal of Wood Science》2004,50(5):455-458

A modified rate equation, in which the diffusion of reagent was taken into consideration, was proposed and applied to results reported previously for the acetylation of wood. The equation was fitted more successfully to the prolonged as well as the early stage of the reaction than a common first-order rate equation. Although the conclusions were virtually unchanged, the reliability was enhanced because reaction parameters such as the rate constant, ultimate extent of the reaction, and activation energy calculated for the modified equation were based on much more data than those reported previously. The equation proposed here may be applicable not only to acetylation but to other chemical modifications of cellulosic materials in heterogeneous systems.  相似文献