A molecular survey of 230 serum samples from cattle was studied by PCR-amplification of the citrate synthase gene gltA, the gene coding for protein 190 kDa—ompA—and the gene ompB. The study was carried out in the Ju...A molecular survey of 230 serum samples from cattle was studied by PCR-amplification of the citrate synthase gene gltA, the gene coding for protein 190 kDa—ompA—and the gene ompB. The study was carried out in the Junta of Castilla y León (northern Spain). The results suggest that the molecular study of the serum cattle would not make a good method in epidemiological studies on rickettsiae in this region. But it is necessary to continue and expand the work with more sensitive molecular methods.展开更多
Objective:To report a training course on the laboratory diagnoses of rickettsioses that 10 provincial/city CDCs participated in laboratory external quality assurance(EQA) based on the serological specific antibodies d...Objective:To report a training course on the laboratory diagnoses of rickettsioses that 10 provincial/city CDCs participated in laboratory external quality assurance(EQA) based on the serological specific antibodies detection and rapid PCR amplifying targeted genes of rickettsiae. Methods:An EQA program to evaluate the following laboratory procedures was developed to detect rickettsiae:(1) immunofluorescent assay(IFA) to detect specific antibodies of A. phagocytophilum,R.heilongjiangensis and 0.tsutsugamshi respectively.(2) Two sets of nested PCR were used amplifying groEL genes for most members of the family Rickettsiaceae and amplifying 16SrRNA genes for the most members of family anaplasmae,respectively.A scoring scheme based on the distribution of the median antibody titer values of the serologic assays was designed and a ranking list of the scores of the PCR results based on the detected minimal copy numbers of reference DNA was created.Results:Among nine laboratories who reported the results on time,eight laboratories gave acceptable serologic results,the other one provided an unacceptable antibody titer(1:2 vs median 1:64) results for 0.tsutsugamshi.The limits of detection(LOD) for the PCR amplifying for five references DNA ranged from 1copy/μL to 10~6 copy/μL.Conclusions:We successfully trained and popularized modern diagnostic methods of rickettsiae in 10 provincial CDCs in China and first conducted the EQA projects and evaluated the results.展开更多
【目的】检测Q型烟粉虱Bemisia tabaci(Gennadius)体内Rickettsia的感染情况,研究分析Rickettsia共生菌经烟粉虱传入豇豆植物后的分布、转移效率等。【方法】以Q型烟粉虱为实验材料,利用常规PCR及荧光原位杂交技术(FISH),检测了烟粉虱体...【目的】检测Q型烟粉虱Bemisia tabaci(Gennadius)体内Rickettsia的感染情况,研究分析Rickettsia共生菌经烟粉虱传入豇豆植物后的分布、转移效率等。【方法】以Q型烟粉虱为实验材料,利用常规PCR及荧光原位杂交技术(FISH),检测了烟粉虱体内Rickettsia的感染率,以及Rickettsia传入豇豆植物体内后的存留情况。【结果】Q型烟粉虱可以通过取食将Rickettsia传至豇豆植株内;接虫数量与Rickettsia传入效率及其在取食部位相邻的下部叶片中检测到的起始时间呈负相关;Rickettsia经烟粉虱取食传入豇豆叶片后,集中分布在叶片的韧皮部筛管中;基于16S r RNA的系统发育分析结果表明,Q型烟粉虱体内的Rickettsia与经取食传入豇豆叶片的Rickettsia高度同源。【结论】Rickettsia可以通过烟粉虱的取食传入植物体内,并且可以在相邻叶片之间转移传播,Rickettsia在由寄主昆虫向植株传播过程中高度保守。展开更多
目的确认长角血蜱是否具有经卵传播斑点热群立克次体(Spotted fever group rickettsia,SFGR)新基因型Candidatus Rickettsia longicornii的能力。方法采集牛体表饱血长角血蜱,在实验室诱导产卵,并采用聚合酶链式反应检测蜱卵中Candidatu...目的确认长角血蜱是否具有经卵传播斑点热群立克次体(Spotted fever group rickettsia,SFGR)新基因型Candidatus Rickettsia longicornii的能力。方法采集牛体表饱血长角血蜱,在实验室诱导产卵,并采用聚合酶链式反应检测蜱卵中Candidatus R. longicornii核酸。扩增长角血蜱母体和蜱卵中Candidatus R. longicornii基因序列,分析同源性和遗传进化关系。结果共采集55只饱血长角血蜱(雌性成蜱),检测Candidatus R. longicornii核酸,21只阳性,阳性率为38.18%。共收集约2 500只长角血蜱蜱卵,分成50组检测Candidatus R. longicornii,6组阳性,蜱卵最低感染率为0.24%。经同源性分析,长角血蜱母体和蜱卵Candidatus R. longicornii基因序列与首次在韩国发现的蜱源ROK-HL727株Candidatus R. longicornii基因序列同源性均达到99.79%以上。母体和蜱卵2个Candidatus R. longicornii基因序列间同源性达到99.69%以上,在系统进化关系上均与ROK-HL727株基因序列处于同一个分支,且遗传关系较近。结论长角血蜱母体SFGR Candidatus R. longicornii基因型感染率较高,且可经卵传播该基因型。展开更多
Objective:To identify members of genera of rickettsia and O.tsutsugammhi simultaneously.Methods:Rapid and duplex and nested PCR methods have been established by designing primers based on the conserved regions of heat...Objective:To identify members of genera of rickettsia and O.tsutsugammhi simultaneously.Methods:Rapid and duplex and nested PCR methods have been established by designing primers based on the conserved regions of heat shock protein GroEL gene.345 mouse viscera samples including liver,spleen and kidney,96 Xenopsylla cheopis and 32 chiggers collected from Hongta areas of Yuxi city,Yunnan province were tested by the new PCR methods.Results:The result of the study showed that the new PCR methods could identify most members of genera -Rickettsia and Orientia simultaneously with 100%specificity and its sensitivity could test one copy per microliter.The results of detection prevalence of rickettsioses in mouse,flea and mites DNA samples showed that the total rickettsia infection rate in mouse was 34.78%(120/345).The total infection rates in R.typhi,O.t Karp and R.sibirica of mouse samples were 28.12%(97/345),19.71%(68/345) and O. 29%(1/345) respectively.Co-infection rates in R.typhi and 0.t Karp of mouse samples were 13.33%(46/ 345).O.t Karp type has been the main epidemic strain in these areas.Conclusion:We concluded that this PCR method could be used to detect multi-genera rickettsia simultaneously.Molecular evidences provided in this and previous studies strongly support that Hongta areas of Yuxi city are a natural focus for typhus and scrub typhus with the common occurrence of their confection.展开更多
Objective:To investigate the situation of anaplasmosis in Yiyuan county.Shandong Province. Methods:A total of 26 blood samples from febrile patients suspected of anaplasmosis,48 blood samples from healthy farmers,8 fr...Objective:To investigate the situation of anaplasmosis in Yiyuan county.Shandong Province. Methods:A total of 26 blood samples from febrile patients suspected of anaplasmosis,48 blood samples from healthy farmers,8 from dogs,and 10 from goats and 170 ticks were collected in the same area during 2005-2007,and detected by serological and molecular methods.Results: Eight confirmed cases and 6 probable cases were determined using serologic and molecular methods.The seroprevalence of Anaplasma phagocytophilum(A.phagocytophilum) was 26.7% in healthy cases.Nine out of 10 sheep samples and 7 out of 8 dog samples reacted positively to the A.phagocytophilum antigen.PCR amplification and sequencing of the 16SrRNA of,4. phagocytophilum gene showed that some samples from patients,goats and ticks were 100% identical.The seroprevalence of Rickettsia typhi was 22.9%,Orientia tsutsugamushi 6.3%, Rickettsia sibirica 27.1%,Coxiella burnetii 18.8%,Bartonella henselae 31.3%,and Borrelia burgdorferi 41.6%.Conclusions:It is important to make differential diagnosis of febrile patients and to apply treatment with specific antibiotics.It is needed to enforce essential prevention and control measures including tick control and to improve sanitation conditions.展开更多
Scrub typhus infection is an important cause of acute undifferentiated fever in South East Asia. The clinical picture is characterized by sudden onset fever with chills and non-specific symptoms that include headache,...Scrub typhus infection is an important cause of acute undifferentiated fever in South East Asia. The clinical picture is characterized by sudden onset fever with chills and non-specific symptoms that include headache, myalgia, sweating and vomiting. The presence of an eschar, in about half the patients with proven scrub typhus infection and usually seen in the axilla, groin or inguinal region, is characteristic of scrub typhus. Common laboratory findings are elevated liver transaminases, thrombocytopenia and leukocytosis. About a third of patients admitted to hospital with scrub typhus infection have evidence of organ dysfunction that may include respiratory failure, circulatory shock, mild renal or hepatic dysfunction, central nervous system involvement or hematological abnormalities. Since the symptoms and signs are non-specific and resemble other tropical infections like malaria, enteric fever, dengue or leptospirosis, appropriate laboratory tests are necessary to confirm diagnosis. Serological assays are the mainstay of diagnosis as they are easy to perform; the reference test is the indirect immunofluorescence assay(IFA) for the detection of Ig M antibodies. However in clinical practice, the enzyme-linked immuno-sorbent assay is done due to the ease of performing this test and a good sensitivity and sensitivity when compared with the IFA. Paired samples, obtained at least two weeks apart, demonstrating a ≥ 4 fold rise in titre, is necessary for confirmation of serologic diagnosis. The mainstay of treatment is the tetracycline group of antibiotics or chloramphenicol although macrolides are used alternatively. In mild cases, recovery is complete. In severe cases with multi-organ failure, mortality may be as high as 24%.展开更多
Although mitochondria provide eukaryotic cells with certain metabolic advantages, in other ways they may be disadvantageous. For example, mitochondria produce reactive oxygen species that damage both nucleocytoplasm a...Although mitochondria provide eukaryotic cells with certain metabolic advantages, in other ways they may be disadvantageous. For example, mitochondria produce reactive oxygen species that damage both nucleocytoplasm and mitochondria, resulting in mutations, diseases, and aging. The relationship of mitochondria to the cytoplasm is best understood in the context of evolutionary history. Although it is clear that mitochondria evolved from symbiotic bacteria, the exact nature of the initial symbiosis is a matter of continuing debate. The exchange of nutrients between host and symbiont may have differed from that between the cytoplasm and mitochondria in modern cells. Speculations about the initial relationships include the following. (1) The pre-mitochondrion may have been an invasive, parasitic bacterium. The host did not benefit. (2) The relationship was a nutritional syntrophy based upon transfer of organic acids from host to symbiont. (3) The relationship was a syntrophy based upon H2 transfer from symbiont to host, where the host was a methanogen. (4) There was a syntrophy based upon reciprocal exchange of sulfur compounds.The last conjecture receives support from our detection in eukaryotic cells of substantial H2S-oxidizing activity in mitochondria, and sulfur-reducing activity in the cytoplasm.展开更多
Objective:To determine the prevalence of tick-borne pathogens with a particular focus on Rickettsia spp.in ticks collected from cattle in Gauteng and Limpopo Provinces,South Africa.Methods:A total of 200 ticks were co...Objective:To determine the prevalence of tick-borne pathogens with a particular focus on Rickettsia spp.in ticks collected from cattle in Gauteng and Limpopo Provinces,South Africa.Methods:A total of 200 ticks were collected from cattle within the Madala livestock,Pretoria,Gauteng Province and in Mankweng Township,Polokwane,Limpopo Province in 2019.The ticks were morphologically identified and processed individually for a total genomic DNA extraction.Specific primers targetting ompA,ompB,and the 17KDa genes were used for a molecular screening and delineation of Rickettsia from the extracted genetic materials using polymerase chain reaction(PCR)technique.PCR amplicons of positive samples were sequenced bidirectionally using the Sanger sequencing method.Sequences generated were processed and analysed using appropriate bioinformatics software.Results:The ticks were morphologically identified as Amblyomma spp.PCR profiling of the genomic DNA samples revealed the presence of the Rickettsia pathogen in 42(21%)of the ticks collected from both Provinces.Out of the genes profiled,14(7%)were positive for 17KDa,42(21%)for ompA and 32(16%)were positive for ompB genes respectively.The nucleotide blast of the sequenced genomes showed high similarity,as high as 100% with other reference Rickettsia(R.)africae in the GenBank.The phylogenetic analysis of the sequences further validated them as R.africae with their characteristic clustering pattern with related reference sequences.Conclusions:There is an abundance of R.africae in Amblyomma ticks collected from cattle in the study areas.This has serious public health implications as individuals who accidentally get infested with the ticks could acquire R.africae.Hence,adequate precautions in terms of sensitization of farmers about the risk and mass mobilization drive to control the vectors in the areas are highly recommended to safeguard public health.展开更多
文摘A molecular survey of 230 serum samples from cattle was studied by PCR-amplification of the citrate synthase gene gltA, the gene coding for protein 190 kDa—ompA—and the gene ompB. The study was carried out in the Junta of Castilla y León (northern Spain). The results suggest that the molecular study of the serum cattle would not make a good method in epidemiological studies on rickettsiae in this region. But it is necessary to continue and expand the work with more sensitive molecular methods.
基金supported by the China-U.S.Collaborative Program on Emerging and Re-emerging Infectious Diseases(No. IU2GGH000018-01)National Basic Research Program of China(973 Program) 2010CB530200(2010CB530206)the National Natural Science Foundation of China (grant No.30771854)
文摘Objective:To report a training course on the laboratory diagnoses of rickettsioses that 10 provincial/city CDCs participated in laboratory external quality assurance(EQA) based on the serological specific antibodies detection and rapid PCR amplifying targeted genes of rickettsiae. Methods:An EQA program to evaluate the following laboratory procedures was developed to detect rickettsiae:(1) immunofluorescent assay(IFA) to detect specific antibodies of A. phagocytophilum,R.heilongjiangensis and 0.tsutsugamshi respectively.(2) Two sets of nested PCR were used amplifying groEL genes for most members of the family Rickettsiaceae and amplifying 16SrRNA genes for the most members of family anaplasmae,respectively.A scoring scheme based on the distribution of the median antibody titer values of the serologic assays was designed and a ranking list of the scores of the PCR results based on the detected minimal copy numbers of reference DNA was created.Results:Among nine laboratories who reported the results on time,eight laboratories gave acceptable serologic results,the other one provided an unacceptable antibody titer(1:2 vs median 1:64) results for 0.tsutsugamshi.The limits of detection(LOD) for the PCR amplifying for five references DNA ranged from 1copy/μL to 10~6 copy/μL.Conclusions:We successfully trained and popularized modern diagnostic methods of rickettsiae in 10 provincial CDCs in China and first conducted the EQA projects and evaluated the results.
文摘【目的】检测Q型烟粉虱Bemisia tabaci(Gennadius)体内Rickettsia的感染情况,研究分析Rickettsia共生菌经烟粉虱传入豇豆植物后的分布、转移效率等。【方法】以Q型烟粉虱为实验材料,利用常规PCR及荧光原位杂交技术(FISH),检测了烟粉虱体内Rickettsia的感染率,以及Rickettsia传入豇豆植物体内后的存留情况。【结果】Q型烟粉虱可以通过取食将Rickettsia传至豇豆植株内;接虫数量与Rickettsia传入效率及其在取食部位相邻的下部叶片中检测到的起始时间呈负相关;Rickettsia经烟粉虱取食传入豇豆叶片后,集中分布在叶片的韧皮部筛管中;基于16S r RNA的系统发育分析结果表明,Q型烟粉虱体内的Rickettsia与经取食传入豇豆叶片的Rickettsia高度同源。【结论】Rickettsia可以通过烟粉虱的取食传入植物体内,并且可以在相邻叶片之间转移传播,Rickettsia在由寄主昆虫向植株传播过程中高度保守。
文摘目的确认长角血蜱是否具有经卵传播斑点热群立克次体(Spotted fever group rickettsia,SFGR)新基因型Candidatus Rickettsia longicornii的能力。方法采集牛体表饱血长角血蜱,在实验室诱导产卵,并采用聚合酶链式反应检测蜱卵中Candidatus R. longicornii核酸。扩增长角血蜱母体和蜱卵中Candidatus R. longicornii基因序列,分析同源性和遗传进化关系。结果共采集55只饱血长角血蜱(雌性成蜱),检测Candidatus R. longicornii核酸,21只阳性,阳性率为38.18%。共收集约2 500只长角血蜱蜱卵,分成50组检测Candidatus R. longicornii,6组阳性,蜱卵最低感染率为0.24%。经同源性分析,长角血蜱母体和蜱卵Candidatus R. longicornii基因序列与首次在韩国发现的蜱源ROK-HL727株Candidatus R. longicornii基因序列同源性均达到99.79%以上。母体和蜱卵2个Candidatus R. longicornii基因序列间同源性达到99.69%以上,在系统进化关系上均与ROK-HL727株基因序列处于同一个分支,且遗传关系较近。结论长角血蜱母体SFGR Candidatus R. longicornii基因型感染率较高,且可经卵传播该基因型。
基金supported by National Natural Science Foundation of China(No. 30771854)China-U.S.Collaborative Program on Emerging and Re-emerging Infectious Diseases(No. 1U2GGH000018-01)
文摘Objective:To identify members of genera of rickettsia and O.tsutsugammhi simultaneously.Methods:Rapid and duplex and nested PCR methods have been established by designing primers based on the conserved regions of heat shock protein GroEL gene.345 mouse viscera samples including liver,spleen and kidney,96 Xenopsylla cheopis and 32 chiggers collected from Hongta areas of Yuxi city,Yunnan province were tested by the new PCR methods.Results:The result of the study showed that the new PCR methods could identify most members of genera -Rickettsia and Orientia simultaneously with 100%specificity and its sensitivity could test one copy per microliter.The results of detection prevalence of rickettsioses in mouse,flea and mites DNA samples showed that the total rickettsia infection rate in mouse was 34.78%(120/345).The total infection rates in R.typhi,O.t Karp and R.sibirica of mouse samples were 28.12%(97/345),19.71%(68/345) and O. 29%(1/345) respectively.Co-infection rates in R.typhi and 0.t Karp of mouse samples were 13.33%(46/ 345).O.t Karp type has been the main epidemic strain in these areas.Conclusion:We concluded that this PCR method could be used to detect multi-genera rickettsia simultaneously.Molecular evidences provided in this and previous studies strongly support that Hongta areas of Yuxi city are a natural focus for typhus and scrub typhus with the common occurrence of their confection.
基金supported by the National Basic Research Program of China(973 Program) 2010CB530200(2010CB530206)the National Natural Science Foundation of China(No.30771854)National Key Science and Technology Projects of China(Project No.2008ZX10004-008)
文摘Objective:To investigate the situation of anaplasmosis in Yiyuan county.Shandong Province. Methods:A total of 26 blood samples from febrile patients suspected of anaplasmosis,48 blood samples from healthy farmers,8 from dogs,and 10 from goats and 170 ticks were collected in the same area during 2005-2007,and detected by serological and molecular methods.Results: Eight confirmed cases and 6 probable cases were determined using serologic and molecular methods.The seroprevalence of Anaplasma phagocytophilum(A.phagocytophilum) was 26.7% in healthy cases.Nine out of 10 sheep samples and 7 out of 8 dog samples reacted positively to the A.phagocytophilum antigen.PCR amplification and sequencing of the 16SrRNA of,4. phagocytophilum gene showed that some samples from patients,goats and ticks were 100% identical.The seroprevalence of Rickettsia typhi was 22.9%,Orientia tsutsugamushi 6.3%, Rickettsia sibirica 27.1%,Coxiella burnetii 18.8%,Bartonella henselae 31.3%,and Borrelia burgdorferi 41.6%.Conclusions:It is important to make differential diagnosis of febrile patients and to apply treatment with specific antibiotics.It is needed to enforce essential prevention and control measures including tick control and to improve sanitation conditions.
文摘Scrub typhus infection is an important cause of acute undifferentiated fever in South East Asia. The clinical picture is characterized by sudden onset fever with chills and non-specific symptoms that include headache, myalgia, sweating and vomiting. The presence of an eschar, in about half the patients with proven scrub typhus infection and usually seen in the axilla, groin or inguinal region, is characteristic of scrub typhus. Common laboratory findings are elevated liver transaminases, thrombocytopenia and leukocytosis. About a third of patients admitted to hospital with scrub typhus infection have evidence of organ dysfunction that may include respiratory failure, circulatory shock, mild renal or hepatic dysfunction, central nervous system involvement or hematological abnormalities. Since the symptoms and signs are non-specific and resemble other tropical infections like malaria, enteric fever, dengue or leptospirosis, appropriate laboratory tests are necessary to confirm diagnosis. Serological assays are the mainstay of diagnosis as they are easy to perform; the reference test is the indirect immunofluorescence assay(IFA) for the detection of Ig M antibodies. However in clinical practice, the enzyme-linked immuno-sorbent assay is done due to the ease of performing this test and a good sensitivity and sensitivity when compared with the IFA. Paired samples, obtained at least two weeks apart, demonstrating a ≥ 4 fold rise in titre, is necessary for confirmation of serologic diagnosis. The mainstay of treatment is the tetracycline group of antibiotics or chloramphenicol although macrolides are used alternatively. In mild cases, recovery is complete. In severe cases with multi-organ failure, mortality may be as high as 24%.
文摘Although mitochondria provide eukaryotic cells with certain metabolic advantages, in other ways they may be disadvantageous. For example, mitochondria produce reactive oxygen species that damage both nucleocytoplasm and mitochondria, resulting in mutations, diseases, and aging. The relationship of mitochondria to the cytoplasm is best understood in the context of evolutionary history. Although it is clear that mitochondria evolved from symbiotic bacteria, the exact nature of the initial symbiosis is a matter of continuing debate. The exchange of nutrients between host and symbiont may have differed from that between the cytoplasm and mitochondria in modern cells. Speculations about the initial relationships include the following. (1) The pre-mitochondrion may have been an invasive, parasitic bacterium. The host did not benefit. (2) The relationship was a nutritional syntrophy based upon transfer of organic acids from host to symbiont. (3) The relationship was a syntrophy based upon H2 transfer from symbiont to host, where the host was a methanogen. (4) There was a syntrophy based upon reciprocal exchange of sulfur compounds.The last conjecture receives support from our detection in eukaryotic cells of substantial H2S-oxidizing activity in mitochondria, and sulfur-reducing activity in the cytoplasm.
基金funded by SAMRC with grant number RDG2017/18 and the APC was funded by SMU.
文摘Objective:To determine the prevalence of tick-borne pathogens with a particular focus on Rickettsia spp.in ticks collected from cattle in Gauteng and Limpopo Provinces,South Africa.Methods:A total of 200 ticks were collected from cattle within the Madala livestock,Pretoria,Gauteng Province and in Mankweng Township,Polokwane,Limpopo Province in 2019.The ticks were morphologically identified and processed individually for a total genomic DNA extraction.Specific primers targetting ompA,ompB,and the 17KDa genes were used for a molecular screening and delineation of Rickettsia from the extracted genetic materials using polymerase chain reaction(PCR)technique.PCR amplicons of positive samples were sequenced bidirectionally using the Sanger sequencing method.Sequences generated were processed and analysed using appropriate bioinformatics software.Results:The ticks were morphologically identified as Amblyomma spp.PCR profiling of the genomic DNA samples revealed the presence of the Rickettsia pathogen in 42(21%)of the ticks collected from both Provinces.Out of the genes profiled,14(7%)were positive for 17KDa,42(21%)for ompA and 32(16%)were positive for ompB genes respectively.The nucleotide blast of the sequenced genomes showed high similarity,as high as 100% with other reference Rickettsia(R.)africae in the GenBank.The phylogenetic analysis of the sequences further validated them as R.africae with their characteristic clustering pattern with related reference sequences.Conclusions:There is an abundance of R.africae in Amblyomma ticks collected from cattle in the study areas.This has serious public health implications as individuals who accidentally get infested with the ticks could acquire R.africae.Hence,adequate precautions in terms of sensitization of farmers about the risk and mass mobilization drive to control the vectors in the areas are highly recommended to safeguard public health.
文摘【目的】通过研究烟粉虱Bemisia tabaci取食传入植物体内的昆虫内共生菌种类,探明其在不同植物中的分布形态及时空动态。【方法】以B型烟粉虱、棉花、番茄、豇豆为实验材料,利用常规PCR检测烟粉虱取食后传入植物体内的共生菌种类;利用透射电镜(Transmission electron microscope,TEM)检测Rickettsia传入植物后的分布及形态;利用q-PCR技术检测豇豆叶片中Rickettsia含量的动态变化。【结果】B型烟粉虱体内含有原生共生菌Portiera、次生共生菌Rickettsia,Hamiltonella和Hemipteriphilus,但只检测到Rickettsia可经烟粉虱传入棉花、番茄、豇豆植物体内,并可在植物体内存活、转移。在3种植物体内Rickettsia均分布于叶片韧皮部的筛管细胞中。烟粉虱、棉花、番茄组织内的Rickettsia形态基本一致,但豇豆中Rickettsia在形态上较小而钝圆。相同数量的烟粉虱取食,在豇豆体内最先检测到Rickettsia。随着烟粉虱取食时间的增加,豇豆体内的Rickettsia含量先增加后下降;而当无烟粉虱持续取食时,一定时间段内豇豆体内的Rickettsia先下降再小幅度上升,并可以在一定时间内保持不变。基于16S rDNA序列的系统发育分析表明,传入棉花、番茄、豇豆叶片中的Rickettsia与B型烟粉虱体内的Rickettsia高度同源。【结论】Rickettsia可经烟粉虱取食传入植物体内,分布并存活于韧皮部的筛管细胞中,并可在植物不同叶片之间转移;在不同植物宿主中,Rickettsia的形态会发生轻微变化;烟粉虱对Rickettsia的传播效率受到植物种类的影响。
