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1.
A panel of fourteen different monoclonal antibodies was used for detection and analysis of antigenic determinants located on the outer surface protein A (OspA) of the spirochete Borrelia burgdorferi, which is a causative agent of tick-borne borreliosis (Lyme disease). Two main and several minor partially overlapping antigenic determinants have been found on the surface of the OspA protein of Borrelia burgdorferi sensu stricto (strain 297) by lanthanide competition fluoroimmunoassay. One of the main antigenic determinants is located in the N- and the other in the C-half of the OspA molecule. The involvement of the OspA protein in intact Borrelia burgdorferi sensu stricto (four bacterial strains have been analyzed: 297, B31, FR90-594, and CA90-742) is associated with retention of the above-mentioned two major antigenic determinants, but unlike the case of the isolated OspA they are partially overlapping with each other and with other antigenic determinants. The protein of the spirochete Borrelia afzelii (two bacterial strains have been analyzed: Ip-21 and Pko) contains only one antigenic determinant, which is the same as the main determinant of the OspA protein of Borrelia burgdorferi sensu stricto located in the N-half of the OspA molecule.  相似文献   

2.
Unfed adult Ixodes persulcatus ticks were collected from four locations of Nagano and Hokkaido in Japan. Infected Borrelia garinii were investigated by PCR-RFLP of the ospA and ospB gene sequences. The primer set amplified an approximately 1.6-kb DNA fragment (0.7-kb in some strains), and BsrI, BstYI, or NlaIII digestion of the product resulted in six distinctively different PCR-RFLP groups and two independent borrelial strains. The representatives in each PCR-RFLP group and individuals from the borrelial strains were sequenced, and their deduced amino acid sequences were aligned. A neighbor-joining phylogenetic analysis showed that the B. garinii OspA or OspB sequences were each divided into three major clusters including isolates from both the Nagano and Hokkaido locations. There was no local difference in OspA/B sequences between Nagano and Hokkaido. The osp gene of Borrelia burgdorferi sensu lato is highly heterogeneous, and this was also confirmed by our sequence analysis. Some strains of the different PCR-RFLP groups had closely related OspA sequences, while the OspB sequences of these strains were quite different. These findings suggested intraspecies gene exchange and recombination events between the two genes in B. garinii.  相似文献   

3.
In Escherichia coli, the fliC gene encodes flagellin, the protein responsible for eliciting the immunological reaction in H serotyping. Here, the presence of the flagellin fliC gene was studied in 86 Bacillus thuringiensis strains encompassing 67 H serotypes. Nineteen strains from four additional species in the B. cereus sensu lato group, B. cereus, B. anthracis, B. mycoides, and B. weihenstephanensis, were added for comparison purposes. The fliC genes were amplified, cloned and their nucleotide sequences determined and translated into amino acid sequences. A bootstrapped neighbor-joining tree was generated from the alignment of the translated amino acid sequences of the amplicons. Although most B. thuringiensis H serotypes had different flagellin amino acid sequences, some different B. thuringiensis serovars shared identical flagellin amino acid sequences. In addition, although serovars from the same H serotype were sometimes found clustered together, several serovars from the same H serotype carried flagellins with sufficiently different amino acid sequences as to be located on distant clusters. No correlations could be established between flagellin (FliC) protein sequence diversity among B. thuringiensis H serotypes and H serotype diversity. These suggest that the B. thuringiensis fliC gene does not code for the flagellin copy responsible for eliciting the immunological reaction in H serotyping. In a previous study, the authors have shown that the B. thuringiensis hag gene codes for the flagellin copy responsible for eliciting the immunological reaction in H serotyping. It is proposed that the B. thuringiensis fliC gene studied here be renamed and that the so-called hag gene studied before be renamed fliC, both in accordance with the E. coli nomenclature. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

4.
Spirochetes from the Borrelia burgdorferi sensu lato (s.l.). (Spirochaetales: Spirochaetaceae) species complex, including the causative agents of Lyme borreliosis, have been isolated from ticks, vertebrate reservoirs and humans. Previous analyses based on direct molecular detection in ticks indicated a considerable diversity of B. burgdorferi s.l. complex in Serbia. The present study aimed (a) to isolate borrelia strains from Serbia; (b) to determine their genotypic characteristics; and (c) to establish a collection of viable B. burgdorferi s.l. strains for further biological, ecological and genetic studies. For the present study, 231 adult Ixodes ricinus (Ixodida: Ixodidae) ticks from 16 ecologically different localities in Serbia were individually processed to cultivate B. burgdorferi s.l. This led to the isolation of 36 strains. A hbb gene quantitative real‐time polymerase chain reaction (PCR) based on melting temperature determination and ospA gene sequencing were used to genotype the isolated spirochetes. The species identified based on the hbb gene real‐time PCR were: Borrelia lusitaniae (44.4%), Borrelia afzelii (36.1%), Borrelia garinii (13.9%) and Borrelia valaisiana (5.6%), whereas the ospA sequence analysis revealed the occurrence of Borrelia bavariensis. This is the first report of the isolation of B. lusitaniae, B. garinii, B. bavariensis and B. valaisiana strains in Serbia.  相似文献   

5.
Sinorhizobium meliloti natural populations show a high level of genetic polymorphism possibly due to the presence of mobile genetic elements such as insertion sequences (IS), transposons, and bacterial mobile introns. The analysis of the DNA sequence polymorphism of the nod region of S. meliloti pSymA megaplasmid in an Italian isolate led to the discovery of a new insertion sequence, ISRm31. ISRm31 is 2,803 bp long and has 22-bp-long terminal inverted repeat sequences, 8-bp direct repeat sequences generated by transposition, and three ORFs (A, B, C) coding for proteins of 124, 115, and 541 amino acids, respectively. ORF A and ORF C are significantly similar to members of the transposase family. Amino acid and nucleotide sequences indicate that ISRm31 is a member of the IS66 family. ISRm31 sequences were found in 30.5% of the Italian strains analyzed, and were also present in several collection strains of the Rhizobiaceae family, including S. meliloti strain 1021. Alignment of targets sites in the genome of strains carrying ISRm31 suggested that ISRm31 inserts randomly into S. meliloti genomes. Moreover, analysis of ISRm31 insertion sites revealed DNA sequences not present in the recently sequenced S. meliloti strain 1021 genome. In fact, ISRm31 was in some cases linked to DNA fragments homologous to sequences found in other rhizobia species.  相似文献   

6.
Borrelia valaisiana-related spirochetes were detected for the first time in Ixodes granulatus ticks collected in Taiwan. The genetic identities of these detected spirochetes were determined by analyzing the gene sequences amplified by a genospecies-specific polymerase chain reaction assay based on the outer surface protein A (OspA) gene of B. burgdorferi sensu lato. Phylogenetic relationships were analyzed by comparing the sequences of OspA gene obtained from 35 strains of Borrelia spirochetes representing six genospecies of Borrelia. Eight major clades can be easily distinguished by neighbour-joining analysis and were congruent by maximum-parsimony method. Except one strain (KH-74), all these Borrelia spirochetes of Taiwan were genetically affiliated to the same clade with highly homogeneous sequences (97.8–100% similarity), and can be discriminated from other groups of B. valaisiana and other genospecies of Borrelia spirochetes with a sequence divergence ranging from 3 to 19.6%. Moreover, intraspecific analysis also revealed that three distinct groups are evident between the same species of B. valaisiana spirochetes detected in Taiwan. Our results provide the first evidence of B. valaisiana spirochetes detected in I. granulatus ticks collected in Taiwan and demonstrate that all these B. valaisiana spirochetes of Taiwan represent three major groups distinct from the European group of B. valaisiana spirochetes.  相似文献   

7.
Our aim was to investigate the capability of each of three genes, 16S rRNA, gyrB and aroE, to discriminate, first, among Bacillus thuringiensis H serotypes; second, among B. thuringiensis serovars from the same H serotype; and third, among B. thuringiensis strains from the same serovar. The 16S rRNA, gyrB and aroE genes were amplified from 21 B. thuringiensis H serotypes and their nucleotide sequences determined. Additional strains from four B. cereus sensu lato species were included for comparison purposes. These sequences were pair-wise compared and phylogenetic relationships were revealed. Each of the three genes under study could discriminate among B. thuringiensis H serotypes. The gyrB and aroE genes showed a discriminatory power among B. thuringiensis H serotypes up to nine fold greater than that of the 16S rRNA gene. The gyrB gene was retained for subsequent analyses to discriminate B. thuringiensis serovars from the same H serotype and to discriminate strains from same serovar. A total of 42 B. thuringiensis strains, which encompassed 25 serovars from 12 H serotypes, were analyzed. The gyrB gene nucleotide sequences were different enough as to be sufficient to discriminate among B. thuringiensis serovars from the same H serotype and among B. thuringiensis strains from the same serovar. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

8.
Twenty-seven strains of Rhizopus oryzae accumulating predominantly lactic acid were shown to possess two ldh genes, ldhA and ldhB, encoding NAD-dependent lactate dehydrogenases. Variation in nucleotide sequence was identified for each gene from different strains, and similar phylogenetic trees were obtained based on the nucleotide sequences of both genes. The other 21 strains of R. oryzae accumulating predominantly fumaric and malic acids contained a single ORF of ldhB. Compared to the strains accumulating predominantly lactic acid, a lower degree of sequence divergence was found in ldhB, resulting in a separate cluster in the phylogenetic tree. The high similarity (>90%) spanning the ORF and adjacent regions demonstrates that ldhA and ldhB are derived from the same ancestor gene. The strains accumulating predominantly fumaric and malic acids lack functional ldhA, which plays a role in lactic acid synthesis and may form a lineage separated from the strains accumulating predominantly lactic acid in the genus Rhizopus.  相似文献   

9.
Japanese Lyme borrelias classified as ribotype IV is predominant among isolates derived from clinical specimens, reservoir rodents and Ixodes persulcatus ticks, and has been characterized as Borrelia garinii. These B. garinii isolates have antigenic and genetic features apparently different from North American, European and other Asian isolates, especially in major outer surface proteins A (OspA) and B (OspB). In this study, we cloned and sequenced the genes encoding OspA and OspB from B. garinii strain FujiP2 (ribotype IV strain) isolated from I. persulcatus in Shizuoka, Japan. A sequence analysis revealed significant differences to the previously published sequences of ospA and ospB of B. burgdorferi sensu lato. The open reading frames of ospA and ospB consist of 822 and 888 nucleotides corresponding to the proteins of 273 and 295 amino acids, with molecular weights of 29,643 and 31,786 daltons, respectively. The most interesting finding is that the two osp genes share a consensus 282 bp sequence in their carboxy-terminal portions and that the ospB gene is flanked by a 282 bp-long direct repeat sequence. The deduced amino-acid (aa) sequences of OspA and OspB of strain FujiP2 showed 60.1% homology, and have overall similarities of 70.5%, 70.3% and 75.6% to OspAB proteins of B. burgdorferi sensu stricto strain B31, Borrelia afzelii strain ACA1 and Borrelia garinii strain Ip90, respectively.  相似文献   

10.
Partial gyrB sequences (>1 kb) were obtained from 34 type strains of the genus Amycolatopsis. Phylogenetic trees were constructed to determine the effectiveness of using this gene to predict taxonomic relationships within the genus. The use of gyrB sequence analysis as an alternative to DNA–DNA hybridization was also assessed for distinguishing closely related species. The gyrB based phylogeny mostly confirmed the conventional 16S rRNA gene-based phylogeny and thus provides additional support for certain of these 16S rRNA gene-based phylogenetic groupings. Although pairwise gyrB sequence similarity cannot be used to predict the DNA relatedness between type strains, the gyrB genetic distance can be used as a means to assess quickly whether an isolate is likely to represent a new species in the genus Amycolatopsis. In particular a genetic distance of >0.02 between two Amycolatopsis strains (based on a 315 bp variable region of the gyrB gene) is proposed to provide a good indication that they belong to different species (and that polyphasic taxonomic characterization of the unknown strain is worth undertaking). Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. The GenBank accession numbers for the gyrB gene sequences obtained in this study are shown in Table 1.  相似文献   

11.
Borrelia lusitaniae is an Old World species of the Lyme borreliosis (LB) group of tick-borne spirochetes and prevails mainly in countries around the Mediterranean Basin. Lizards of the family Lacertidae have been identified as reservoir hosts of B. lusitaniae. These reptiles are highly structured geographically, indicating limited migration. In order to examine whether host geographic structure shapes the evolution and epidemiology of B. lusitaniae, we analyzed the phylogeographic population structure of this tick-borne bacterium using a recently developed multilocus sequence typing (MLST) scheme based on chromosomal housekeeping genes. A total of 2,099 questing nymphal and adult Ixodes ricinus ticks were collected in two climatically different regions of Portugal, being ∼130 km apart. All ticks were screened for spirochetes by direct PCR. Attempts to isolate strains yielded 16 cultures of B. lusitaniae in total. Uncontaminated cultures as well as infected ticks were included in this study. The results using MLST show that the regional B. lusitaniae populations constitute genetically distinct populations. In contrast, no clear phylogeographic signals were detected in sequences of the commonly used molecular markers ospA and ospC. The pronounced population structure of B. lusitaniae over a short geographic distance as captured by MLST of the housekeeping genes suggests that the migration rates of B. lusitaniae are rather low, most likely because the distribution of mediterranean lizard populations is highly parapatric. The study underlines the importance of vertebrate hosts in the geographic spread of tick-borne microparasites.  相似文献   

12.
【目的】利用16S rRNA和rpoC1基因分子标记研究螺旋藻、节旋藻的系统发育关系,并对其区分能力进行比较。【方法】以84株螺旋藻、节旋藻为研究对象,对其进行16S rRNA、rpoC1基因序列的扩增、测序及分析,并对构建的系统发育树进行对比。【结果】rpoC1基因序列保守位点所占比例49.7%、平均G+C百分含量47.7%和序列相似度76%–100%明显低于16S rRNA基因序列的79.4%、55.6%和91%–100%,其变异程度高于16S rRNA基因;基于16S rRNA、rpoC1基因构建的系统发育NJ树拓扑结构基本一致,84株实验藻株分为2个属3个类群,其中仅F-351、F-904-2、F-1070和TJBC14-1藻株为螺旋藻,其余均为节旋藻;虽然2个基因都不能区分形态种和地理种,但rpoC1基因NJ树的置信度(100%)高于16S rRNA基因(99%),属内分群效果也明显优于16S rRNA基因。【结论】支持了螺旋藻、节旋藻为两个不同属的结论,且在属内分类时rpoC1基因比16S rRNA基因具有更高的区分度。  相似文献   

13.
The genetic identity of Ixodes granulatus ticks was determined for the first time in Taiwan. The phylogenetic relationships were analyzed by comparing the sequences of mitochondrial 16S ribosomal DNA gene obtained from 19 strains of ticks representing seven species of Ixodes and two outgroup species (Rhipicephalus sanguineus and Haemaphysalis inermis). Four major clades could be easily distinguished by neighbour-joining analysis and were congruent by maximum-parsimony method. All these I. granulatus ticks of Taiwan were genetically affiliated to a monophyletic group with highly homogeneous sequences (92.2–99.3% similarity), and can be discriminated from other Ixodes species and other genera of ticks with a sequence divergence ranging from 11.7 to 30.8%. Moreover, intraspecific analysis revealed that two distinct lineages are evident between the same species of I. granulatus ticks collected from Taiwan and Malaysia. Our results demonstrate that all these I. granulatus ticks of Taiwan represent a unique lineage distinct from the common vector ticks (I. ricinus complex) for Borrelia burgdorferi spirochetes.  相似文献   

14.
15.
In Europe the initial skin manifestation of Lyme borreliosis (erythema migrans) is predominantly caused by Borrelia afzelii while nervous system involvement is usually associated with Borrelia garinii. The aim of our study was to compare protein profiles of B. afzelii and B. garinii isolated from skin of patients with erythema migrans and from cerebrospinal fluid (CSF) of patients with Lyme neuroborreliosis. We analyzed 187 Borrelia strains, 74 B. afzelii and 113 B. garinii, for the presence of flagellin, and outer surface proteins A, B and C. Their protein profiles were obtained by SDS–PAGE and analyzed by computer program Gel Doc. Differences in the presence of proteins were found comparing isolates according to species (B. afzelii and B. garinii) and to their origin (skin and CSF isolates); the heterogeneity regarding the presence or absence of borrelial proteins was established within particular species. Protein profiles of the analyzed strains showed differences in the number, amount and molecular mass of analyzed proteins. Distinctions in the synthesis of outer surface proteins may play a role in the dispersal of borreliae within and between animal reservoir and vector ticks, as well as in pathogenesis of Lyme borreliosis in humans.  相似文献   

16.
Interest in species of the genus Penicillium is related to their ability to produce the mycotoxin patulin and to cause spoilage of fruit products worldwide. The sequence of the isoepoxydon dehydrogenase (idh) gene, a gene in the patulin biosynthetic pathway, was determined for 28 strains representing 12 different Penicillium species known to produce the mycotoxin patulin. Isolates of Penicillium carneum, Penicillium clavigerum, Penicillium concentricum, Penicillium coprobium, Penicillium dipodomyicola, Penicillium expansum, Penicillium gladioli, Penicillium glandicola, Penicillium griseofulvum, Penicillium paneum, Penicillium sclerotigenum and Penicillium vulpinum were compared. Primer pairs for DNA amplification and sequencing were designed from the P. griseofulvum idh gene (GenBank AF006680). The two introns present were removed from the nucleotide sequences, which were translated to produce the IDH sequences of the 12 species for comparison. Phylogenetic relationships among the species were determined from rDNA (ITS1, 5.8 S, ITS2 and partial sequence of 28S rDNA) and from the idh nucleotide sequences minus the two introns. Maximum parsimony analysis showed trees based on rDNA and idh sequences to be congruent. It is anticipated that the genetic information obtained in the present study will aid in the design of probes, specific for patulin biosynthetic pathway genes, to identify the presence of these mycotoxigenic fungi. The U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.  相似文献   

17.
Partial gyrA sequences were determined for twelve strains belonging to Bacillus amyloliquefaciens, B. atrophaeus, B. licheniformis, B. mojavensis,B. subtilis subsp. subtilis, B. subtilissubsp. spizizenii and B. vallismortis. The average nucleotide and translated amino acid similarities for the seven type strains were 83.7 and 95.1%, respectively, whereas the corresponding value for the 16S rRNA sequences was 99.1%. All of the type strains were sharply separated; the closest relationship was found between B. atrophaeus and B. mojavensis which shared a nucleotide similarity of 95.8%. Phylogenetic trees were inferred from gyrA nucleotide sequences using the neighbor-joining, Fitch–Margoliash and maximum parsimony algorithms. The test strains were divided into four groups, which generally reflected results previously reported in restriction digest and DNA-DNA hybridization studies. It is concluded from the comparative sequence analysis that the gyrA sequences provide a firm framework for the rapid and accurate classification and identification of Bacillus subtilis and related taxa.  相似文献   

18.
The genetic diversity of Frankia strains nodulating Alnus glutinosa along the basin of the Tormes River was studied on DNA extracted directly from nodules. Frankia strains inhabiting root nodules at 12 different locations, ranging in altitude from 409 to 1181 m, were characterized. For that, we amplified the whole IGS region between 16S–23S rDNA and performed a restriction fragment length polymorphism (RFLP) analysis with four restriction enzymes. Two different RFLP patterns (termed A and B) were obtained with HaeIII, indicating the existence of two different groups of Frankia strains. Three different nodule extracts from each of the two RFLP groups were selected for further analyses. Sequencing of the 16S–23S rDNA IGS showed a 100% of intragroup homology and also confirmed the difference (98.4% level of similarity) between the Frankia strains in the two nodule extract groups. The phylogenetic analyses based on the two 16S–23S rDNA IGS sequences obtained in this study and other previously published sequences indicated that Frankia strains TFAg5 and TFAg23 (chosen as representative of HaeIII–RFLP group A and B, respectively) are quite similar to other strains nodulating plants of A. rhombifolia and A. viridis in California (pairwise levels of similarity including gaps ranged from 97.8% to 98.6%), together with which they form a single group. To put the Frankia strains representative of each HaeIII–RFLP group in the context of overall Frankia diversity we amplified and sequenced the 16S rDNA and glnII gene from nodular DNA. An also remarkable fact found in this study was that Frankia strains belonging to the HaeIII–RFLP group A were distributed all along the river course, from the lowest site sampled to the highest, while Frankia strains placed into RFLP group B were restricted to the upper Tormes River, being exclusively found at altitudes of 946 m or higher.  相似文献   

19.
From the cloned mitochondrial DNAs (mtDNAs) isolated from two bisexual species, one Mediterranean, Artemia salina, and one American, Artemia franciscana, and two parthenogenetic (diploid and tetraploid) strains of Artemia parthenogenetica collected in Spain, physical maps have been constructed and compared. They are extremely different among themselves, much more than the differences between Drosophila melanogaster and D. yakuba and in the same range of different mammalian species such as mouse/rat or man/cow. The nucleotide sequences of two regions of mtDNA encoding parts of the cytochrome c oxidase subunit I (COI) and cytochrome b (Cytb) genes have been determined in the two bisexual species and the two parthenogenetic strains. Comparisons of these sequences have revealed a high degree of divergence at the nucleotide level, averaging more than 15%, in agreement with the differences found in the physical maps. The majority of the nucleotide changes are silent and there is a strong bias toward transitions, with the CT substitutions being highly predominant. The evolutionary distance between the two Artemia parthenogenetica is high and there is no clear relationship with any of the bisexual species, including the one present nowadays in Spain. Using a combination of molecular (mtDNA) and morphological markers it is possible to conclude that all of these Artemia isolates should be actually considered as belonging to different species, even the two Artemia parthenogenetica diploidica and tetraploidica.On sabbatical leave from Departamento de Bioquímica, Facultad de Veterinaria, Universidad Complutense de Madridearly Italian artemiologists to designate the Medi-Beatriz Batuecas died in an accident during the Christmas holy days of 1988 after she had initiated this workCorrespondence to: R. Garesse  相似文献   

20.
Sixty-one Borrelia burgdorferi sensu lato strains from various sources (ticks, human, and wild animals) in Japan and two strains from ticks in Far Eastern Russia were classified on the basis of reactivity with 16 monoclonal antibodies (mAb) to outer surface protein A (OspA) and by DNA-DNA hybridization assay. Eleven OspA serotypes (J1 to J11) were recognized among the Japanese and the Far East Russian isolates (serotypes J1 to J9 were identified as B. garinii, serotype J10 was identified as B. afzelii, and serotype J11 corresponded to B. japonica), whereas 7 OspA serotypes for North American and European isolates previously reported (Bettina Wilske et al, J. Clin. Microbiol. 31:340-350, 1993) were not observed except for OspA serotype 2 which showed identical reactivity with OspA serotype J10. This finding provides helpful information for understanding the geographical distribution of Lyme disease borrelia and the development of vaccine and diagnostic tests. In conclusion: 1. B. burgdorferi sensu stricto has not been observed in Japan, 2. Japanese B. afzelii isolates are closely related to those from Europe, 3. B. garinii isolates from Japan are highly heterogeneous and apparently different from European B. garinii isolates.  相似文献   

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