Abstract We have previously identified a Brucella melitensis 28 kDa cytosoluble protein (CP28) which was highly immunogenic in infected sheep and which in addition made possible the serological differentiation between infected and B. melitensis Rev.l vaccinated sheep. Monoclonal antibodies against CP28 were used to screen a B. melitensis 16M genomic library and to clone the corresponding gene. DNA sequencing of the gene encoding CP28 of B. melitensis 16M revealed that it was nearly identical to that of the recently published bp26 gene of Brucella abortus vaccine strain S19 coding for a periplasmic protein. The differences between the B. melitensis 16M gene and that of B. abortus S19 consisted of single nucleotide substitutions, one or two codon deletions, one codon addition, and most importantly a 21-bp deletion. The corresponding region of B. abortus S19 contains two 10-bp direct repeats which could have been involved in the genesis of the deletion. Expression of the B. melitensis 16M bp26 gene in Escherichia coli studied by the use of the monoclonal antibodies showed the same characteristics as reported for the B. abortus S19 bp26 gene, i.e. the presence of a higher molecular mass preprotein and a lower molecular mass band which probably corresponds to the mature protein exported to the periplasm. Immunoblotting performed with sera from either naturally infected or B. melitensis H38 experimentally infected sheep confirmed the importance of the B. melitensis CP28/BP26 protein as diagnostic antigen. 相似文献
Dromedary camels (Camelus dromedarius) play a major economic role in many countries in Africa and Asia. Although they are resistant to harsh environmental conditions, they are susceptible to a wide range of zoonotic agents. This study aimed to provide an overview on the prevalence of selected zoonotic pathogens in blood and tissues of camels in central Iran. Blood, liver, portal lymph node, and brain were collected from 100 apparently healthy camels at a slaughterhouse in Qom city to assess the presence of DNA of Brucella spp., Trypanosoma spp., Coxiellaburnetii, and Bartonella spp. PCR products were sequenced bidirectionally and phylogenetic analyses were performed. Eleven percent of camels tested positive for Brucellaabortus (3%) and Trypanosomaevansi (8%). Coxiellaburnetii and Bartonella spp. DNA was not detected. Our data demonstrate that camels from Iran contribute to the epidemiology of some zoonotic pathogens. Performing proper control strategies, such as vaccination of camels and humans in contact with them, test-and-slaughter policy, and education of the general population is necessary for minimizing the risk of zoonotic infection. 相似文献
Bacterial and protozooan intracellular parasites have evolved diverse mechanisms for evasion of host cellular defenses associated with adaptations for survival in distinct intracellular compartments. As the reagents identifying discrete steps in vesicle maturation and trafficking have become increasingly available, it has become clear that the vacuoles occupied by intracellular parasites are much more diverse than had been previously appreciated. Many parasites induce selective fusion competence with the vacuoles they occupy, without affecting vesicular trafficking elsewhere in the cell. A likely means of controlling vesicular interactions is modification of the parasitophorous vacuole membrane by the insertion of parasite-specific proteins. A rapidly expanding class of bacterial proteins that modify the vacuolar membrane are the chlamydial inclusion membrane proteins. Although the functions of most of these proteins remain to be defined, the majority are expressed early in the infectious process, suggesting that modification of the vacuole is critical to the outcome of the host–parasite interaction. 相似文献
Brucella abortus is the etiologic agent of bovine brucellosis and causes a chronic disease in humans known as undulant fever. In livestock the disease is characterized by abortion and sterility. Live, attenuated vaccines such as S19 and RB51 have been used to control the spread of the disease in animals; however, they are considered unsafe for human use and they induce abortion in pregnant cattle. For the development of a safer and equally efficacious vaccine, immunoproteomics was utilized to identify novel candidate proteins from B. abortus cell envelope (CE). A total of 163 proteins were identified using 2-DE with MALDI-TOF MS and LC-MS/MS. Some of the major protein components include outer-membrane protein (OMP) 25, OMP31, Omp2b porin, and 60 kDa chaperonin GroEL. 2-DE Western blot analyses probed with antiserum from bovine and a human patient infected with Brucella identified several new immunogenic proteins such as fumarate reductase flavoprotein subunit, F0F1-type ATP synthase alpha subunit, and cysteine synthase A. The elucidation of the immunome of B. abortus CE identified a number of candidate proteins for developing vaccines against Brucella infection in bovine and humans. 相似文献
Water buffalo (Bubalus bubalis) are affected by high rates of embryonic mortality and abortion related to infectious diseases and non-infectious factors. A number of viral and bacterial infections have been associated with reproductive failure, but there is limited information on the role of chlamydial infections.
In order to investigate the presence and the role of Chlamydiaceae in water buffalo a retrospective study was performed in a herd with a history of reproductive failure. During an 11-month period, the pregnant heifers suffered an abortion rate of 36.8% between the 3rd and 7th month of pregnancy. Antibodies to Chlamydiaceae were detected in 57% of the aborted cows, and in 0% of the overtly healthy cows used as control. By a nested-PCR assay, three of 14 vaginal swabs from aborted animals tested positive for Chlamydophila agents and, additionally, three out of seven aborted fetuses tested positive for Chlamydophila spp., with two being co-infections by Cp. abortus and Cp. pecorum and one being characterised as Cp. abortus. Sequence analysis of the amplicons confirmed the results of the nested-PCR. The presence of anti-Chlamydiaceae antibodies in more than half of the aborting animals (P < 0.002) and the detection of Chlamydophila agents in several fetal organs and in the vaginal swabs are consistent with the history of abortions observed in the herd and suggest an abortifacient role by Chlamydophila spp. in water buffalo (B. Bubalis) herds. 相似文献
Chlamydophila pneumoniae is one of the most important and well studied gram negative bacterial strain with respect to community
acquired pneumonia and other respiratory diseases like Chronic obstructive pulmonary disease (COPD), Chronic asthma,
Alzheimer''s disease, Atherosclerosis and Multisclerosis which have a great potential to infect humans and many other mammals.
According to WHO prediction, COPD is to become the third leading cause of death by 2030. Unfortunately, the molecular
mechanisms leading to chronic infections are poorly understood and the difficulty in culturing C pneumoniae in experimental
conditions and lack of entirely satisfactory serological methods for diagnosis is also a hurdle for drug discovery and development.
We have performed an insilico synteny based comparative genomics analysis of C pneumoniae and other eight Chlamydial
organisms to know the potential of C pneumoniae which cause COPD but other Chlamydial organisms lack in potential to cause
COPD though some are involved in human pathogenesis. We have identified total 354 protein sequences as non-orthologous to
other Chlamydial organisms, except hypothetical proteins 70 were found functional out of which 60 are non homologous to Homo
sapiens proteome and among them 18 protein sequences are found to be essential for survival of the C pneumoniae based on BLASTP
search against DEG database of essential genes. CELLO analysis results showed that about 80% proteins are found to be
cytoplasmic, Among which 5 were found as bacterial exotoxins and 2 as bacterial endotoxins, remaining 11 proteins were found to
be involved in DNA binding, RNA binding, catalytic activity, ATP binding, oxidoreductase activity, hydrolase activity and
proteolysis activity. It is expected that our data will facilitate selection of C pneumoniae proteins for successful entry into drug
design pipelines. 相似文献
Lipocalin 2 (Lcn2) is an important innate immunity component against bacterial pathogens. In this study, we report that Lcn2 is induced by Brucella (B.) abortus infection and significantly contributes to the restriction of intracellular survival of Brucella in macrophages. We found that Lcn2 prevented iron uptake by B. abortus through two distinct mechanisms. First, Lcn2 is secreted to capture bacterial siderophore(s) and abrogate iron import by Brucella. Second, Lcn2 decreases the intracellular iron levels during Brucella infection, which probably deprives the invading Brucella of the iron source needed for growth. Suppression of Lcn2 signalling resulted in a marked induction of anti‐inflammatory cytokine, interleukin 10, which was shown to play a major role in Lcn2‐induced antibrucella immunity. Similarly, interleukin 6 was also found to be increased when Lcn2 signalling is abrogated; however, this induction was thought to be an alternative pathway that rescues the cell from infection when the effective Lnc2 pathway is repressed. Furthermore, Lcn2 deficiency also caused a marked decrease in brucellacidal effectors, such as reactive oxygen species and nitric oxide but not the phagolysosome fusion. Taken together, our results indicate that Lcn2 is required for the efficient restriction of intracellular B. abortus growth that is through limiting iron acquisition and shifting cells to pro‐inflammatory brucellacidal activity in murine macrophages. 相似文献