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1.
The present study was conducted to clarify the mechanism underlying the oxidative process in erythrocytes infected with Babesia gibsoni. The parasite B. gibsoni was cultured together with erythrocytes from normal dogs for 7 days. When parasitemia reached 12.0-13.4% at Day 7. the production of superoxide in erythrocytes was significantly higher in the parasitized culture than in the control culture (p<0.005). The concentration of thiobarbituric acid reactive substances (TBARS) in erythrocytes in parasitized culture was also significantly increased compared with the control culture (p<0.005), indicating that lipid peroxidation was greater in infected erythrocytes than in non-infected cells. In addition, the rates of superoxide generation in the blood of B. gibsoni-infected dogs were also significantly higher than in non-infected dogs (p<0.001). These results indicate that superoxide anions are increased in erythrocytes parasitized with B. gibsoni. and suggest that oxidative damage, due to lipid peroxidation, might be caused in host erythrocytes by the parasite.  相似文献   

2.
Cattle were immunized againts infection with a heterogologous strain of Babesia argentina by the subcuntaneous inoculation of killed antigen mixed with Freund's complete adjuvant. The most effective antigen, infectted erythrocyte antigen (IEA), which confered protection comparable with that conferred by the presence of subclinical infection, was prepared by the disruption of parasitized erythrocytes in a French pressure cell. In contrast, antigen prepared from the plasma of infected animals was weakly immunogenic. The inoculation of IEA by the intravenous route without adjuvant did not confer protection but demonstrated the presence of a “kallikrein activating” substances(s) in the contents of the parasitized erythrocytes.  相似文献   

3.
Babesia divergens was cultivated in sheep erythrocytes in RPMI 1640 supplemented with 10% Fetal Calf Serum (FCS) or sheep serum. In vitro cultures in sheep red blood cells were initiated with human erythrocytes infected in vitro with B. divergens Rouen 1987 or with gerbil blood infected with several isolates from bovine origin. After the first subcultures on sheep erythrocytes, a ten-fold multiplication of the parasites was obtained within 48 h. Erythrocytes from three splenectomized sheep were infected in vitro with B. divergens; when parasitaemia reached 10%, the animals were inoculated with homologous parasitized erythrocytes. All sheep expressed hyperthermia with a peak between the 6th and the 9th day post-infection (p-i) and a transitory parasitaemia 10 days p-i. In vitro primary cultures were performed on two of these sheep, demonstrating the parasite persistence at very low parasitaemia in the infected animals. Splenectomized sheep can be used as a new model for B. divergens chronic infection.  相似文献   

4.
Guan G  Ma M  Liu A  Du P  Ren Q  Li Y  Wang J  Liu Z  Yin H  Luo J 《Veterinary parasitology》2012,187(3-4):371-378
Babesia sp. Xinjiang was isolated from a splenectomised sheep infested by Rhipicephalus sanguineus and Hylomma anatolicum anatolicum, collected from sheep and cattle in Xinjiang province. It was considered to be a novel ovine Babesia species on the basis of its morphology, pathogenicity, vector tick species and alignments of 18S ribosomal RNA (18S rRNA) and internal transcribed spacers (ITS) gene sequences. Continuous in vitro cultures of the ovine parasite were established using infected sheep blood. In RPMI 1640 medium with 7.5% sheep red blood cells (RBCs) maintained in an incubator at 37 °C and 5% CO(2), the percentage of parasitized erythrocytes (PPE) peaked at 10% in 24- and 6-well plates. It increased to 20-50% with the same culture medium but with 2.5% RBC in 75 cm(2) flasks. Two clonal lines of Babesia sp. Xinjiang were screened using the limiting dilution method. Growth characteristics of these lines in vitro were measured by a microtiter-based spectrophotometric method and from the PPE. The generation time in sheep erythrocytes was between 15.20 h and 16.27 h. Furthermore, the host range of parasite was identified with in vitro culture and in vivo infection. Erythrocytes of sheep, cattle, sika deer and humans could be invaded into by lines in vitro, but the parasites could not propagate in human erythrocytes. The parasites could not enter erythrocytes from goats in vitro. However, in vivo, only sheep could be infected by lines. Finally, a Babesia sp. Xinjiang-like parasite (which shared 99.5% identity with the original strain of Babesia sp. Xinjiang) was isolated using this in vitro culture system from 1 of 19 sheep blood samples collected from western Gansu province, China.  相似文献   

5.
To account for the conflict between the excessive destruction of erythrocytes and the number of parasitized erythrocytes in dogs infected with Babesia gibsoni, we examined the correlation between anti-erythrocyte membrane antibody level (AEMAL) and the number of erythrocytes (RBC count) in dogs with experimentally induced babesiosis using hematological examination and an enzyme linked immunosorbent assay (ELISA). In the infected dogs without splenectomy, more prominent reduction in RBC count accompanied with the elevated AEMAL was presented than anticipated from parasitemia until the 21st day. Furthermore, autoagglutinated erythrocytes and spherocytes were demonstrated in blood films. These results suggest that a humoral immunologic mechanism may be involved in a decrease in RBC count in dogs infected with B. gibsoni.  相似文献   

6.
Peripheral blood samples from dogs infected with Babesia gibsoni were analyzed by a flow cytometer for the percentage of reticulocytes after staining with a membrane-permeable fluorochrome, thiazole orange. Though thiazole orange has been reported to stain human reticulocytes and Plasmodium-infected erythrocytes, number of positive cells determined by the flow cytometry did not include that of erythrocytes infected with Babesia gibsoni. Analysis of 51 samples revealed a correlation coefficient of 0.96 as compared to the conventional determination by light microscopy. Separation of reticulocytes from Babesia gibsoni-infected erythrocytes by flow cytometry with or without the stain remained unresolved.  相似文献   

7.
应用冷冻血清对1株采自自然感染的水牛牛巴贝斯虫进行了长达72d的体外连续培养,共继代20次,培养72h红细胞染虫率最高达14.1%,平均为8%~10%。培养20d和30d的牛巴贝斯虫经液氮保存复苏后,接种于去脾水牛犊均引发了严重的牛巴贝斯虫病,从而说明已建立了水牛牛巴贝斯虫的体外连续培养,且经培养后的牛巴贝斯虫致病力没有改变。本试验利用6头份的冷冻健康水牛血清同时进行培养,结果发现,并非所有的健康水牛血清均适合于体外培养牛巴贝斯虫。这一发现对建立水牛牛巴贝斯虫的体外培养和研究水牛牛巴贝斯虫病均具有重要意义  相似文献   

8.
Spleens of two cats infected with Haemobartonella felis were examined by electron microscopy to determine the means by which the organism was sequestered in this organ. The principal means of sequestration occurred when H felis, located on the erythrocytes was removed by phagocytosis by a cordal macrophage, apparently preceded by the adhesion of extended processes of the macrophage to H felis. The second and least frequent means of removal of H felis was by pitting, a process that did not cause destruction of the host erythrocyte. The H felis was pitted from the parasitized erythrocyte when H felis passed through gaps between reticular cells or when the parasitized erythrocyte passed among the cytoplasmic processes of the reticular cells in the splenic cords. Some H felis were closely associated with the plasmalemma of cordal reticular cells and also were located in intracytoplasmic vacuoles of the cells without being influenced by the phagocytic process.  相似文献   

9.
巴贝斯虫病水牛血清钙镁浓度变化与染虫率的关系   总被引:1,自引:0,他引:1  
自水牛巴贝斯虫病非疫区购买的无任何血液原虫寄生的健康水牛犊2头,人工摘除脾脏后,用从疫区采集的饥饿镰形扇头蜱叮咬感染,观察巴贝斯虫的消长与血清钙、镁浓度的变化,结果发现二者关系密切,其中钙离子浓度与红细胞染虫率呈负相关,镁离子浓度与红细胞染虫率呈正相关,这一发现为进一步研究水牛巴贝斯虫病及在体内外研究巴贝斯虫的生长繁殖均具有重要意义。  相似文献   

10.
Four splenectomized Welsh ponies were infected with Babesia equi. Two ponies were treated with imidocarb dipropionate, and two were not treated. By light microscopic examination, 1% to 2% of the parasitized erythrocytes of treated ponies contained crystalline inclusions. The crystals were rectangular, diamond, or burr shaped. They occupied most of the erythrocytic cytoplasm, and, as a result, the remainder of the pale staining cytoplasm was inconspicuous in Wright-Giemsa-stained blood smears. The size and shape of intraerythrocytic inclusions varied when examined by electron microscopy, but in most instances they were either adhered to or were located close to the parasite. The sides of crystals were either smooth or serrated, and corners were either sharp or notched. Fractures or faults were common in large crystals. Parasitized erythrocytes of nontreated ponies and nonparasitized erythrocytes of treated ponies did not contain crystals. Four hemoglobulin types were identified in five noninfected, nontreated Welsh ponies from the same herd.  相似文献   

11.
Bovine erythrocytes infected with Babesia bovis were analysed for parameter changes known to influence rigidity and deformability of erythrocytes. Marked increases in malonyldialdehyde were detected indicating that lipid peroxidation occurs during infection. Consequently, increases in membrane lipid, methaemoglobin and membrane-bound haemoglobin were detected. Conversely, decreases in the antioxidant vitamin E and decreases in sialic acid were also detected. The cumulative effect of these changes would be to increase erythrocyte rigidity and decrease deformability thus contributing to the microvascular stasis characteristic of acute B bovis infection.  相似文献   

12.
The osmotic fragility and the surface structure of erythrocytes obtained from 3 calves infected with Theileria sergenti and from 3 phlebotomized ones were compared. As the parasitemia progressed, the osmotic fragility of the erythrocytes significantly increased in the infected calves. Particularly the hemolysis ratio in the isotonic area (21.5-94.1%) obviously increased. On the other hand, the percentage of parasitized cells in the erythrocytes did not show so much high values (16.1-21.3%). Similar phenomenon was found in each different percentage of erythrocytes suspension which was separated from density gradient centrifugation. No significant difference in the serum osmotic pressure between the infected calves and the phlebotomized calves was found. By scanning microscopy, the erythrocytes of infected calves, which were collected at the crisis period of parasitemia, were almost completely deformed and showed echinocyte form. Moreover, the appearance ratio of echinocyte form in the erythrocytes population was superior to the percentage of parasitized erythrocytes. Similar membranous alterations were also observed in the erythrocytes of grazing cattle in the crisis period of the theileriosis. It was proven that abnormality of osmotic fragility and morphological disorders of erythrocytes occurred not only in parasitized erythrocytes but also in non-parasitized ones in T. sergenti parasitemia.  相似文献   

13.
In the present study, we employed flow cytometry to evaluate the level of parasitemia of Babesia gibsoni infecting canine erythrocytes in vivo and in vitro by using fluorescent nucleic acid staining. Peripheral blood samples from a B. gibsoni-infected dog and cultured B. gibsoni parasitizing in canine erythrocytes were stained with a membrane-permeable fluorescent nucleic acid stain, SYTO16. In this study, we utilized normal canine erythrocytes (LK erythrocytes) and canine erythrocytes containing high concentrations of potassium, reduced glutathione, and some free amino acids (HK erythrocytes) as host cells for culture. Parasitized cells in vive were discriminated completely from unparasitized cells and a correlation (r = 0.998) between the percentage of SYTO16-positive cells and parasitemia in vivo was observed. On the other hand, erythrocytes in vitro could not be divided clearly into parasitized and unparasitized cells. However, when LK erythrocytes were used as host cells, the percentage of SYTO16-positive cells was almost the same as, and was well correlated (r = 0.932) with, the level of parasitemia. When HK erythrocytes were used as host cells, the percentage of SYTO16-positive cells was almost half of, but was correlated (r = 0.982) with, the level of parasitemia. Therefore, we attempted to observe the changes in the percentage of parasitized cells after treatment with antiprotozoal drug or mitochondria inhibitors by using flow cytometry. The changes in the percentage of SYTO16-positive cells corresponded well with the changes of the level of parasitemia when the parasites in HK erythrocytes were cultured with each compound. The present results suggest that flow cytometric detection using SYTO16 is a rapid and reliable method for monitoring parasitemia both in vive and in vitro.  相似文献   

14.
We describe a nested polymerase chain reaction (PCR) for the detection of Babesia equi in equine infected erythrocytes using oligonucleotides designed on the published sequence of a B. equi merozoite antigen gene (ema-1). A 102bp DNA fragment is specifically amplified from B. equi but not from Babesia caballi, Babesia bovis or Babesia bigemina DNA. In a mock infection we were able to detect down to six infected cells in 10(8) equine erythrocytes or to detect the parasite in blood with an equivalent parasitemia of 0.000006%. Furthermore, gene polymorphism was found by performing a PCR-RFLP (PCR combined with restriction fragment length polymorphism) on both the 102bp and the entire ema-1 gene DNA amplified from two B. equi isolates, Florida (USA) and Pelotas (Southern Brazil) isolates. The polymorphism was confirmed by sequencing the entire ema-1 gene from the B. equi isolate Pelotas. Our results demonstrate that the ema-1 based nested PCR is a valuable technique for routine detection of B. equi in chronically infected horses. It may be used for epidemiological and phylogenetic studies of the parasite as well as monitoring B. equi infected horses in chemotherapeutic trials.  相似文献   

15.
Ovine erythrocytes infected with attenuated Anaplasma marginale organisms were cultured in a suspension of normal ovine erythrocytes and normal bovine erythrocytes for 42 days. In each system, the organism showed an initial period of rapid growth followed by a gradual decrease in the percentage of parasitized erythrocytes accompanied by cyclic peaks. The percentage of infection of ovine erythrocytes were not different when normal ovine or bovine erythrocytes were added to the cultures. In vitro transmission of the organism from infected ovine cells to normal bovine cells was demonstrated by use of a two-step direct fluorescent antibody method, which allowed for specific identification of the two cell types and the organism.  相似文献   

16.
An electron microscope study of thin sections of bovine erythrocytes parasitized with Babesia bovis (Texas isolate) revealed that the body of the parasite is covered with a pellicular complex consisting of three membranes, two located on the interior and one on the outer part of the pellicle. Parasites observed possessed one nucleus and one nucleolus containing aggregated nuclear material. Each of these aggregations was bounded by two nuclear membranes. Organelles such as polar rings, rhoptries, micronemes, vesicular structures, cisternae of the nuclear membrane, spherical bodies, mitochondria-like structures and Maurer's clefts were indentified and described. The basic similarities and differences in the intra-erythrocytic stages of Babesia bovis, in comparison with other Babesia spp. parasites, are discussed.  相似文献   

17.
The complement fixation (CF) test and the capillary-tube agglutination (CA) test were used to study the antigenic relationship between Babesia bigemina and the large Babesia species frequently infecting cattle in Japan. The CF antigen was prepared from parasitized erythrocytes by extraction with distilled water. The CA antigen was prepared from parasitized erythrocytes by mild sonification of mixtures of Babesia and erythrocyte stroma, following lysis of the erythrocytes with hypotonic saline solution. All the sera used were collected from experimentally-infected cattle. Cross reaction was demonstrated between the Japanese Babesia species and B. bigemina. There was, however, a difference of two dilutions in titer between homologous and heterologous antibody in the CF test, and a difference of more than three tubes in titer between both antibodies in the CA test. It was possible, therefore, to distinguish the Japanese Babesia species from B. bigemina by the CF and CA tests.  相似文献   

18.
For studying protein trafficking in Babesia-infected erythrocyte, we describe the cloning of a Rab5, one of molecular marker for vesicle trafficking in eukaryotic cells, gene homologue in Babesia gibsoni (BgRab5). The full-length cDNA of BgRab5 is 1,020 bp long with an open reading frame encoding a protein of 220 amino acids. The deduced amino acid sequence of BgRab5 contained the highly conserved GTP-binding consensus sequence and shares about 40% homology with that of Rab5 from Plasmodium falciparum, Toxoplasma gondii, Dog, Lotus japonicusor, Oryza sativa. Northern blot analysis showed that the BgRab5 probe hybridized with a 1kb band in total RNA from parasitized erythrocytes, that was consistent with the size of the BgRab5 full-length cDNA.  相似文献   

19.
Blood cell parasitaemia of Babesia microti and the associated haematological changes were examined in mice harbouring patent Fasciola hepatica infections and in fluke-free control mice. B. microti parasitaemia was markedly suppressed in mice harbouring primary 7-week F. hepatica infections, as reflected in a reduction in the percentage of erythrocytes parasitised and in the incidence of multiple B. microti infections in the red cells. This suppression was accompanied by an annulment of B. microti induced reductions in haemoglobin and haematocrit levels in F. hepatica infected mice. In naive recipient mice, inoculated with blood from mice concurrently infected with F. hepatica and B. microti, the course of B. microti infection was characterised by a prolonged pre-parasitaemia period, a reduced peak parasitaemia and a delayed fall in haematocrit levels as compared to those inoculated with blood from mice infected with B. microti only. This feature may presumably be dose-related. The present study does not reveal the actual mechanism(s) involved in the suppression of the blood protozoan by F. hepatica. However, since B. microti has a preference for mature erythrocytes, the suppression may be a result of the altered erythrocyte kinetic state induced by the removal of erythrocytes by the blood-sucking fluke resulting in high levels of reticulocytes.  相似文献   

20.
将分离于中国河南省的一株牛的巴贝西原虫用长角血蜱(Haemaphysalis longicomis)幼虫对牛进行了实验感染.依据感染牛呈现的临床症状、媒介蜱、红细胞内裂殖子出现的时间及形态学特征,以及荧光抗体试验结果,确认该原虫为卵形巴贝西虫(Babesia ovata).  相似文献   

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