首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
Mycoplasma pulmonis m53 was inoculated intraarticularly in the bilateral hind footpads and bilateral knee joints of BALB/c mice. Mycoplasmas were recovered from the affected joints over 20 weeks accompanying acute or subacute inflammation. Intensive deposition of immunoglobulins, a complement (C3) and mycoplasma cell antigens occurred in synovial and adjacent connective tissues. The histopathologically intact kidneys, brain, and lungs showed deposition of IgG and the complement on the endothelial cells of blood vessels. An IgG-rheumatoid factor like substance (RFLS) was detected in the serum of the mice by an enzyme-linked immunoabsorbent assay. Persistence of mycoplasma cells and immune complexes in the articular tissues might cause the prolongation of inflammatory responses in murine mycoplasmal arthritis.  相似文献   

2.
Histopathological examinations were performed on arthritic joints and other organs of strain BALB/cA nu/nu and nu/+ mice intravenously injected with Mycoplasma pulmonis strain m53. In both groups of mice suffering from polyarthritis, acute inflammatory lesions with infiltration of polymorphonuclear leukocytes in the synovia and periarticular tissues were observed one to two weeks after injection. In nu/nu mice, the acute inflammation appeared repeatedly up to 20 weeks after inoculation, when the experiment was terminated, and furthermore, extensive synovial and periarticular necrosis were characteristically present after the 4th week. Only a small number of lymphocytes and plasma cells were in the lesions. In nu/+ mice, after the early acute inflammation of arthritis, relapses of the infiltration of polymorphonuclear leukocytes were also observed in some mice in and after the 10th week. In addition, infiltration of lymphocytes and plasma cells was substantial after the 15th week. Focal necrosis was sometimes found in the liver of nu/nu mice. Perivascular infiltration of small lymphocytes and plasma cells was found in the lungs, liver and kidney of nu/+ mice in and after the 15th week. Repair mechanisms of injured articular tissues in nu/nu mice were histopathologically poor, while those in nu/+ mice seemed to be progressive and quite similar to those reported by many investigators for mice with the thymus intact. The histopathological differences are discussed in respect to the thymus-dependent immune responses.  相似文献   

3.
Experiments were undertaken to examine gene transfer in Mycoplasma pulmonis. Parent strains containing transposon-based tetracycline and chloramphenicol resistance markers were combined to allow transfer of markers. Two mating protocols were developed. The first consisted of coincubating the strains in broth culture for extended periods of time. The second protocol consisted of a brief incubation of the combined strains in a 50% solution of polyethylene glycol. Using either protocol, progeny that had acquired antibiotic resistance markers from both parents were obtained. Analysis of the progeny indicated that only the transposon and not flanking genomic DNA was transferred to the recipient cell. Gene transfer was DNase resistant and probably the result of conjugation or cell fusion.  相似文献   

4.
Serological heterogeneity of Mycoplasma pulmonis   总被引:4,自引:0,他引:4  
  相似文献   

5.
Localization of Mycoplasma pulmonis was examined in mice infected by direct contact with previously infected mice. After contact with infected animals, the organisms were shown to become detectable first in the nasal and oral cavities and trachea on the next day, and then they were recovered from the middle ear and brain after 3 and 4 days, respectively. After 7 days of contact, isolation rates retained to be 100% in the nasal, oral and tracheal cavities, while 95% in the middle ear and brain, 25% in the lung and 20% in the vagina and uterus. The number of colonies was the most numerous from the nasal, uterine and vaginal cavities, followed by the trachea, middle ear, oral cavity, brain and lung in this order, except for a few mice having pneumonic lesions giving a large number of the organisms. The isolation rates with these organs were not changed even after 6 weeks of contact and organisms were never detected from the liver, spleen, kidney and heart. Mice from a naturally infected breeding colony showed similar finding to those sacrificed after 6 weeks of experimental contact.  相似文献   

6.
Transmission of Mycoplasma pulmonis between rats   总被引:1,自引:0,他引:1  
A Hill 《Laboratory animals》1972,6(3):331-336
  相似文献   

7.
The gliding movements of freshly isolated Mycoplasma pulmonis cells were observed and measured. The motile cells had a characteristic appearance, an average speed of 0.4 to 0.7 micron/s, and a maximum speed of 1 micron/s.  相似文献   

8.
High-frequency variation in Mycoplasma pulmonis colony size.   总被引:4,自引:4,他引:4       下载免费PDF全文
Heterogeneity in colony size of the murine pathogen Mycoplasma pulmonis was examined. Subcloning experiments showed that colony size variation resulted from high-frequency genetic changes. About 3% of the colonies from any given subclone were variants, with as much as a fourfold change in colony diameter. When the variants were propagated in liquid broth, their doubling times in logarithmic growth phase reflected the colony sizes obtained on agar. Colony size variation correlated with changes in the electrophoretic properties of the V-1 surface antigen.  相似文献   

9.
Humoral antibody response to sheep red blood cells and cellular immune response to bovine serum albumin were studied in Mycoplasma pulmonis infected, adult, male Sprague-Dawley rats. The hemagglutinating antibody response to sheep red blood cells was evaluated at 0, 3, 5, 7, 14, 21 and 28 days postinfection. Antibody titers during all days postinfection were depressed significantly (p less than 0.05) in infected rats as compared to noninfected controls. Cellular immune responses were evaluated by a delayed hypersensitivity response. Rats were sensitized at 0, 3, 5, 7, 14, 21 or 28 days postinfection with bovine serum albumin and challenged with heat aggregated bovine serum albumin 7 days later. Cell-mediated immune responses in infected rats were not significantly different at any point from controls. These results indicate that M. pulmonis infection in rats suppresses the humoral antibody response to sheep red blood cells, but not the cellular immune response to bovine serum albumin.  相似文献   

10.
Sequential pathogenicity of Mycoplasma pulmonis in laboratory rats   总被引:2,自引:0,他引:2  
  相似文献   

11.
The polymerase chain reaction for Mycoplasma pulmonis   总被引:2,自引:0,他引:2  
In vitro DNA amplification by polymerase chain reaction was examined to detect Mycoplasma pulmonis. A pair of synthetic oligonucleotide primers was constructed, and used to amplify a unique sequence of M. pulmonis DNA. Amplified products were detected by agarose gel electrophoresis and verified by blot hybridization with a synthetic oligonucleotide probe. This system detected cellular DNA of M. pulmonis but not M. arthritidis or M. neurolyticum, and thus appears to be useful for M. pulmonis diagnosis.  相似文献   

12.
The expression of Mycoplasma pulmonis antigen in Escherichia coli was investigated by cloning genomic DNA derived from M. pulmonis m 53, and the DNA fragment participating in antigen expression was identified. When the DNA library of M. pulmonis was screened by colony immunoassay using anti-M. pulmonis serum, 10 recombinant clones expressing seroreactive antigens were obtained. The recombinant plasmids isolated from these clones included 3.7-6.5 kilobase pair (kbp) DNA inserts, while all clones contained a common 2.3-kbp DNA fragment. Subcloning of initial DNA inserts showed that the common 2.3-kbp fragment is essential for antigen expression. Moreover, antiserum against the recombinant antigen generated from the 2.3-kbp DNA fragment recognized a native M. pulmonis antigen. The reactivity of this antiserum was absorbed specifically with M. pulmonis. These results suggest that the cloned 2.3-kbp DNA fragment codes an antigen specific to M. pulmonis.  相似文献   

13.
Electrophoretic patterns of strains of Mycoplasma pulmonis   总被引:3,自引:0,他引:3  
  相似文献   

14.
The vsa genes of Mycoplasma pulmonis encode the V-1 lipoproteins. Most V-1 proteins contain repetitive domains and are thought to be involved in mycoplasma-host cell interactions. Previously, we have reported the isolation and characterization of six vsa genes comprising a 10-kb region of the genome of M. pulmonis strain KD735-15. In the current study, vsa-specific probes were used to clone several fragments from a genomic library of KD735-15 DNA and assemble a single 20-kb contig containing 11 vsa genes. The middle region of the vsa locus contains a large open reading frame (ORF) that is not a vsa gene and has undergone an internal deletion in some strains. The ORF is predicted to encode a membrane protein that may have a role in disease pathogenesis. To examine vsa genes in a strain of M. pulmonis that is unrelated to KD735-15, strain CT was studied. Through Southern hybridization and genomic cloning analyses, CT was found to possess homologs of the KD735-15 vsaA, -C, -E, and -F genes and two unique genes (vsaG and vsaH) that were not found in KD735-15. High-frequency, site-specific DNA inversions serve to regulate the phase-variable production of individual V-1 proteins. As a result of the sequence analysis of vsa recombination products, a model in which DNA inversion arises from strand exchange involving at least six nucleotides of the vrs box is proposed.  相似文献   

15.
Mycoplasma pulmonis depresses humoral and cell-mediated responses in mice   总被引:2,自引:0,他引:2  
Humoral and cell-mediated immune responses to sheep red blood cells (SRBC) were studied in mice infected experimentally with Mycoplasma pulmonis. The hemagglutinating (HA) antibody against SRBC was evaluated at 0, 3, 5, 7, 14, 21 and 28 days postinfection (PI). Antibody tiers during all days PI were depressed significantly (p less than 0.05) in infected mice as compared to noninfected controls. The HA antibody, which is of the IgM class, peaks at day 5 PI. There is no shift in the kinetics of the humoral response in M. pulmonis infected mice. Cellular immune responses were evaluated by a delayed-type hypersensitivity (DTH) reaction and the lymphocyte transformation technique. Mice were sensitized at 0,3,5,7,14, 21 and 28 days PI with SRBC and challenged by footpad injection of SRBC 7 days later. The DTH reaction measured at 24 hours after challenge was depressed significantly (p less than 0.05) in all infected animals. After a transient enhancement on day 3 PI, the DTH responses remained depressed through day 28 PI. The lymphocyte transformation test showed a significantly (p less than 0.05) depressed response except on days 5 and 7 PI. These results indicate that M. pulmonis infection in mice suppresses the humoral antibody and cell-mediated immune responses.  相似文献   

16.
17.
Mycoplasma pulmonis is a murine pathogen that causes chronic respiratory disease in laboratory rats and mice. Several examples of high-frequency phenotypic switching have been reported for M. pulmonis, the molecular basis of which is unknown. We report here that during growth the M. pulmonis chromosome undergoes DNA rearrangements at a high frequency. Some of the rearrangements we examined correlated with changes in the susceptibility of the cells to mycoplasma virus P1, an example of phenotypic switching involving changes in surface antigen structure. Other rearrangements, unrelated to phenotypic switching, involved a DNA element present in the chromosome in multiple copies. The high level of DNA recombination that occurred in M. pulmonis indicates that this may be one of the most variable genomes studied to date. High levels of DNA recombination may contribute to the unusually high rate of evolution that mycoplasmas are thought to be undergoing. Understanding the molecular basis for this phenomenon may provide an insight into the chronic nature of many mycoplasmal infections.  相似文献   

18.
19.
Cell-mediated and humoral immune responses in mice after challenge exposure with Mycoplasma pulmonis were investigated. The cell-mediated immune response was determined by means of the delayed-type footpad swelling and the humoral immune response by means of the indirect haemagglutination test. Delayed-type footpad swelling and serum antibody titres were detected at one week after the challenge exposure and persisted for 7 weeks until the end of the experiment. However, there was a poor correlation between the degree of delayed-type footpad swelling and that of serum antibody titre. Delayed-type footpad swelling in mice with gross pneumonic lesions was less than that of mice with no gross lesions. A weak negative linear correlation was observed between the delayed-type footpad swelling and the number of M. pulmonis isolated from lungs.  相似文献   

20.
Bacterial biofilms are communities of bacteria that are enclosed in an extracellular matrix. Within a biofilm the bacteria are protected from antimicrobials, environmental stresses, and immune responses from the host. Biofilms are often believed to have a highly developed organization that is derived from differential regulation of the genes that direct the synthesis of the extracellular matrix and the attachment to surfaces. The mycoplasmas have the smallest of the prokaryotic genomes and apparently lack complex gene-regulatory systems. We examined biofilm formation by Mycoplasma pulmonis and found it to be dependent on the length of the tandem repeat region of the variable surface antigen (Vsa) protein. Mycoplasmas that produced a short Vsa protein with few tandem repeats formed biofilms that attached to polystyrene and glass. Mycoplasmas that produced a long Vsa protein with many tandem repeats formed microcolonies that floated freely in the medium. The biofilms and the microcolonies contained an extracellular matrix which contained Vsa protein, lipid, DNA, and saccharide. As variation in the number of Vsa tandem repeats occurs by slipped-strand mispairing, the ability of the mycoplasmas to form a biofilm switches stochastically.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号