Application of the Numerical Characteristic of Formal Order Analysis of the Prokaryotic Genomes for Reclassification within the Genus Rickettsia

2016 ◽  
Vol 11 (2) ◽  
pp. 336-350 ◽  
Author(s):  
С.Н. Шпынов ◽  
S.N. Shpynov
Keyword(s):  
Spotted Fever ◽  
Numerical Characteristic ◽  
Spotted Fever Group ◽  
Rickettsia Felis ◽  
New Approach ◽  
Order Analysis ◽  
Ancestral Group ◽  
Prokaryotic Genomes ◽  
Information Chain

Genomes representing Rickettsiaceae family were analyzed using formal order analysis (FOA) of information chain in order to develop a new approach for the classification of prokaryotes. Average remoteness – the numerical characteristic of order was used to compare the genomes. FOA allows one to directly take into account arrangement of nucleotides in each sequence. The obtained results clarified the previously known classification. In addition Rickettsia felis group was discovered between the ancestral group and spotted fever group (SFG) and R. akari group located between the SFG and genus Orientia. Software used for the analysis of nucleotide sequences with FOA is freely available at http://foarlab.org.

scholarly journals Antigenic Classification of Rickettsia felis by Using Monoclonal and Polyclonal Antibodies

2003 ◽  
Vol 10 (2) ◽  
pp. 221-228 ◽  
Author(s):  
Rong Fang ◽  
Didier Raoult
Keyword(s):  
Monoclonal Antibodies ◽  
Polyclonal Antibodies ◽  
Spotted Fever ◽  
Spotted Fever Group ◽  
Neighbor Joining ◽  
Rickettsia Felis ◽  
Polyclonal Antisera ◽  
Antigenic Profile ◽  
Sfg Rickettsia

ABSTRACT Rickettsia felis is a flea-transmitted rickettsia. There is a discrepancy between its reported phylogenic and phenotypic identifications. Following the first report of R. felis, it was considered by tests with serologic reagents to be closely related to another recognized flea-transmitted rickettia, R. typhi. Subsequently, it appeared to be more closely related to spotted fever group (SFG) rickettsiae by genetic analysis. In the present work, R. felis was studied by microimmunofluorescence (MIF) serologic typing and with monoclonal antibodies (MAbs). Mouse polyclonal antisera to R. felis cross-reacted only with SFG rickettsiae. A neighbor-joining analysis based on MIF indicated that R. felis is actually related to SFG rickettsiae antigenically, clustering with R. australis, R. akari, and R. montanensis. A panel of 21 MAbs was raised against a 120-kDa protein antigen or a 17-kDa polypeptide of R. felis. They cross-reacted with most members of the SFG rickettsiae but not with R. prowazekii, R. typhi, or R. canadensis of the typhus group (TG) rickettsiae. Sixty-four MAbs previously generated to seven other ricketttsial species were tested with R. felis. Three MAbs reacted with the 120-kDa antigen and were generated by R. africae, R. conorii, and R. akari, respectively. They exhibited cross-reactivities with R. felis. All our data show that R. felis harbors the antigenic profile of an SFG rickettsia.

scholarly journals GENOMOSYSTEMATICS OF RICKETTSIAE

2018 ◽  
Vol 8 (2) ◽  
pp. 107-118 ◽  
Author(s):  
S. N. Shpynov ◽  
N. N. Pozdnichenko ◽  
A. S. Gumenyuk ◽  
A. A. Skiba
Keyword(s):  
Spotted Fever ◽  
Methodological Approach ◽  
Integrated Approach ◽  
Spotted Fever Group ◽  
Rickettsia Felis ◽  
Single Chromosome ◽  
Ancestral Group ◽  
Ecological Features ◽  
A Genome ◽  
Complete Genomes

The definition of the term genome was given by the German botanist G. Winkler almost one hundred years ago in 1920. A genome  definition for bacterial (rickettsia) with a single chromosome was  recently presented from the perspective of information theory,  biology and bioinformatics as the information chain of nucleotides.  The systematics of rickettsiae (obligate intracellular microorganisms) is based on a limited number of phenotypic characters.  Classifications built on the analysis of genes, fragments of genomes  and their concatenations cause discussion. Application of the Formal  Order Analysis (FOA, http://foarlab.org) in the study of complete  genomes allowed to submit the systematics of representatives of the family Rickettsiaceae. This approach confirmed the existence of  typhus group (TG), spotted fever group (SFG), and an «ancestral»  group within the genus Rickettsia, and allowed the isolation of the  Rickettsia felis group within this genus, located between the  «ancestral» group and the SFG and the R. akari group on the border  between the SFG group and the genus Orientia. The development of  the tools of FOA — «Map of Genes» and «Matrix of Similarity» —  helped to conduct an in-depth study of the complete genomes of  rickettsia, taking into account the characteristics of their genes and  noncoding sequences. Application of these instruments, with the  help of the obtained classification, confirmed the notion of ecological  features of rickettsia, the structure of nosological forms and the  epidemiological patterns of rickettsiosis, and made it possible to  assess the virulence of the strains of the two most pathogenic  species of rickettsia, R. prowazekii and R. rickettsia. In this work, for the first time, a holistic, consistent and multidimensional observation of a set of closely related bacteria (a family of bacteria) and the  manifestations associated with them was carried out. The basis of  the developed and herein described systematic approach to the  study of bacteria is a new mathematical model — the arrangement of nucleotides in a complete genome and its sensitive  unambiguous numerical characteristics. A new methodological  approach named genomosystematics and based on mathematical  modeling of complete genomes of rickettsiae (bacteria) using FOA.  Classification of rickettsiae and rickettsioses obtained with the help  of this approach corresponds to ecological, epidemiological and  etiological principles. Application of the genomosystematics can  serve the goals and objectives of preventive medicine. The  publication completes a series of scientific works presenting the  methodology of an integrated approach based on the application of  mathematical analysis tools in the study of objects and laws of  natural science disciplines of biological and medical profile.

scholarly journals Genetic Classification of “Rickettsia heilongjiangii” and “Rickettsia hulinii,” Two Chinese Spotted Fever Group Rickettsiae

2000 ◽  
Vol 38 (9) ◽  
pp. 3498-3501 ◽  
Author(s):  
J. Z. Zhang ◽  
M. Y. Fan ◽  
Y. M. Wu ◽  
P. E. Fournier ◽  
V. Roux ◽  
...  
Keyword(s):  
Spotted Fever ◽  
Phylogenetic Position ◽  
Spotted Fever Group ◽  
Neighbor Joining ◽  
Likelihood Methods ◽  
Genetic Classification ◽  
Repeat Units ◽  
Statistical Bootstrap ◽  
Maximum Likelihood Methods

To determine the phylogenetic position of two new rickettsial strains isolated from ticks in China, 16S ribosomal DNA,gltA, and ompA (apart from the tandem repeat units) genes were amplified by PCR and sequenced. The phylogenetic relationships between these strains and other rickettsiae were inferred from the comparison of sequences of the three genes by the parsimony, neighbor-joining, and maximum-likelihood methods. The results demonstrated that the 054 strain, a rickettsia pathogenic in humans, and the HL-93 strain were related and clustered together withRickettsia japonica. Significant statistical bootstrap values (100 and 92%) supported the nodes in this cluster. Based on previous genotypic and antigenic data and the phylogenetic analysis presented here, the 054 and HL-93 strains should be considered as new species, and we formally propose that they be named “Rickettsia heilongjiangii” and “Rickettsia hulinii,” respectively.

scholarly journals Seasonal and Gender Differences in Presence of Rickettsia felis and Blood meals Provide Additional Evidence of a Vector Role for Mosquitoes

2019 ◽  
Vol 2019 ◽  
pp. 1-5
Author(s):  
Jilei Zhang ◽  
Guangwu Lu ◽  
Patrick John Kelly ◽  
Chengming Wang
Keyword(s):  
Gender Differences ◽  
Blood Meal ◽  
Mosquito Species ◽  
Spotted Fever ◽  
Infection Model ◽  
Spotted Fever Group ◽  
Egg Hatching ◽  
Rickettsia Felis ◽  
And Gender

Rickettsia felis belongs to spotted fever group Rickettsia and is an emerging human pathogen most commonly transmitted by a range of fleas and ticks. While recent evidence has suggested mosquitoes are infected with R. felis, there is little information about the role of mosquitoes in the organism’s transmission. In this study, around 100 mosquitoes were collected monthly between 2013 and 2014 from the same residential dwelling at Yangzhou, China. The collected mosquitoes were identified for their species and gender, followed by gltA-based PCR and hydroxymethylbilane synthase-based PCR to determine the prevalence of Rickettsia and blood meal. Three mosquito species (Culex pipiens: 76%, 996/1,304; C. tritaeniorhynchus: 17%, 216/1,304; Aedes albopictus: 7%, 92/1,304) were identified. For 1,088 female mosquitoes, 31% of them n=336 were positive for blood meal and 7% n=77 carried R. felis DNA. In a strong contrast, none of the 216 male mosquitoes were positive for blood meal but two males were positive for Rickettsia. Interestingly, 63% of R. felis-positive mosquitoes (50/79) were negative for blood meal, being significantly higher than 37% of mosquitoes and being positive for both R. felis and blood meal P=0.008. Furthermore, we compared the prevalence of Rickettsia and blood meal in the mosquitoes collected in the months with temperature below and above 23°C, the minimum temperature required for mosquito egg hatching. Mosquitoes captured in the months below 23°C showed significant higher positivity of R. felis(71/936, 7.6% vs. 8/368, 2.2%; P=0.002) and blood meal (294/936, 31.4% vs. 36/368, 9.8%; P<10−4) than in the months above 23°C. Collectively, the seasonal and gender differences of R. felis and blood meal in mosquitoes add to the existing evidence, supporting a potential vector role of mosquitoes in the transmission of R. felis. Studies with a R. felis infection model covering the full life cycle of mosquitoes is necessary to unambiguously prove the transstadial and transovarial transmission of R. felis in mosquitoes.

scholarly journals Rickettsia hoogstraalii sp. nov., isolated from hard- and soft-bodied ticks

2010 ◽  
Vol 60 (4) ◽  
pp. 977-984 ◽  
Author(s):  
Darja Duh ◽  
Volga Punda-Polic ◽  
Tatjana Avsic-Zupanc ◽  
Donald Bouyer ◽  
David H. Walker ◽  
...  
Keyword(s):  
Cell Cultures ◽  
Novel Species ◽  
Spotted Fever ◽  
Vero Cells ◽  
Embryonic Cell ◽  
Spotted Fever Group ◽  
The Novel ◽  
Rickettsia Felis ◽  
Separate Species ◽  
Genotypic Characteristics

A novel spotted fever group Rickettsia was found in Haemaphysalis sulcata ticks collected from sheep and goats in Croatia in 2006. At the same time, a genetically identical organism was co-isolated with the embryonic cell line CCE3 obtained from the soft tick Carios capensis in Georgia, USA. In this study, further phenotypic and genotypic characteristics of the novel rickettsial strain present in H. sulcata ticks were investigated. Based on the cultivation of bacteria in mosquito and Vero cell cultures, the presence of rickettsiae in tick tissues and cell cultures [confirmed by transmission electron microscopy (TEM)] and the amplification and sequencing of five rickettsial genes, it was demonstrated that the novel Rickettsia strain fulfils the criteria to be classified as a novel species. The name Rickettsia hoogstraalii sp. nov. is proposed for the new strain. Rickettsia hoogstraalii sp. nov., an obligately intracellular bacterium, was grown in Vero cells and arthropod CCE3, ISE6 and C6/36 cell lines. The morphology of the cells of the novel species was typical of SFG rickettsiae. The small coccobacillary appearance of the bacteria was apparent with light microscopy. A Gram-negative bacterial cell wall and a cytoplasmic membrane separated by a narrow periplasmic space were visible by TEM. To date, Rickettsia hoogstraalii sp. nov. has been isolated from two species of ticks, H. sulcata and C. capensis. The novel species appears to be geographically widely distributed, having been detected in Croatia, Spain and Georgia, USA. Although no information is available regarding the possible pathogenicity of the novel species for vertebrate hosts, R. hoogstraalii sp. nov. has a cytopathic effect in Vero, CCE3 and ISE6 cells. Sequence analyses of the 16S rRNA, 17 kDa, gltA, ompA and ompB genes indicated that even though R. hoogstraalii sp. nov. was closely related to Rickettsia felis, it represents a separate species within the spotted fever group. The type strain of R. hoogstraalii sp. nov. is strain CroaticaT (=DSM 22243T=UTMB 00003T).

scholarly journals Propagation of Arthropod-Borne Rickettsia spp. in Two Mosquito Cell Lines

2007 ◽  
Vol 73 (20) ◽  
pp. 6637-6643 ◽  
Author(s):  
Joyce M. Sakamoto ◽  
Abdu F. Azad
Keyword(s):  
Cell Line ◽  
Cell Lines ◽  
Spotted Fever ◽  
Culture Conditions ◽  
Spotted Fever Group ◽  
Rickettsia Felis ◽  
Transitional Group ◽  
Mosquito Cell Lines

ABSTRACT Rickettsiae are obligate intracellular alphaproteobacteria that include pathogenic species in the spotted fever, typhus, and transitional groups. The development of a standardized cell line in which diverse rickettsiae can be grown and compared would be highly advantageous to investigate the differences among and between pathogenic and nonpathogenic species of rickettsiae. Although several rickettsial species have been grown in tick cells, tick cells are more difficult to maintain and they grow more slowly than insect cells. Rickettsia-permissive arthropod cell lines that can be passaged rapidly are highly desirable for studies on arthropod-Rickettsia interactions. We used two cell lines (Aedes albopictus cell line Aa23 and Anopheles gambiae cell line Sua5B) that have not been used previously for the purpose of rickettsial propagation. We optimized the culture conditions to propagate one transitional-group rickettsial species (Rickettsia felis) and two spotted-fever-group rickettsial species (R. montanensis and R. peacockii) in each cell line. Both cell lines allowed the stable propagation of rickettsiae by weekly passaging regimens. Stable infections were confirmed by PCR, restriction digestion of rompA, sequencing, and the direct observation of bacteria by fluorescence in situ hybridization. These cell lines not only supported rickettsial growth but were also permissive toward the most fastidious species of the three, R. peacockii. The permissive nature of these cell lines suggests that they may potentially be used to isolate novel rickettsiae or other intracellular bacteria. Our results have important implications for the in vitro maintenance of uncultured rickettsiae, as well as providing insights into Rickettsia-arthropod interactions.

scholarly journals Rickettsia felis from Cat Fleas: Isolation and Culture in a Tick-Derived Cell Line

2006 ◽  
Vol 72 (8) ◽  
pp. 5589-5595 ◽  
Author(s):  
Walairat Pornwiroon ◽  
Susan S. Pourciau ◽  
Lane D. Foil ◽  
Kevin R. Macaluso
Keyword(s):  
Cell Line ◽  
Citrate Synthase ◽  
Ixodes Scapularis ◽  
Spotted Fever ◽  
Protein A ◽  
Etiologic Agent ◽  
Host Cells ◽  
Spotted Fever Group ◽  
Rickettsia Felis ◽  
Cat Fleas

ABSTRACT Rickettsia felis, the etiologic agent of spotted fever, is maintained in cat fleas by vertical transmission and resembles other tick-borne spotted fever group rickettsiae. In the present study, we utilized an Ixodes scapularis-derived tick cell line, ISE6, to achieve isolation and propagation of R. felis. A cytopathic effect of increased vacuolization was commonly observed in R. felis-infected cells, while lysis of host cells was not evident despite large numbers of rickettsiae. Electron microscopy identified rickettsia-like organisms in ISE6 cells, and sequence analyses of portions of the citrate synthase (gltA), 16S rRNA, Rickettsia genus-specific 17-kDa antigen, and spotted fever group-specific outer membrane protein A (ompA) genes and, notably, R. felis conjugative plasmids indicate that this cultivatable strain (LSU) was R. felis. Establishment of R. felis (LSU) in a tick-derived cell line provides an alternative and promising system for the expansion of studies investigating the interactions between R. felis and arthropod hosts.

scholarly journals Human Spotted Fever Group Rickettsioses Are Underappreciated in Southern Taiwan, Particularly for the Species Closely-Related to Rickettsia felis

PLoS ONE ◽  
2014 ◽  
Vol 9 (4) ◽  
pp. e95810 ◽  
Author(s):  
Chung-Hsu Lai ◽  
Lin-Li Chang ◽  
Jiun-Nong Lin ◽  
Kun-Hsien Tsai ◽  
Ya-Chien Hung ◽  
...  
Keyword(s):  
Spotted Fever ◽  
Spotted Fever Group ◽  
Rickettsia Felis ◽  
Southern Taiwan

scholarly journals Rickettsia felis: molecular characterization of a new member of the spotted fever group.

2001 ◽  
Vol 51 (2) ◽  
pp. 339-347 ◽  
Author(s):  
D H Bouyer ◽  
J Stenos ◽  
P Crocquet-Valdes ◽  
C G Moron ◽  
V L Popov ◽  
...  
Keyword(s):  
Molecular Characterization ◽  
Spotted Fever ◽  
Spotted Fever Group ◽  
Rickettsia Felis

scholarly journals Rickettsia felis (Rickettsiales: Rickettsiaceae) in Ctenocephalides felis felis (Siphonaptera: Pulicidae) in the State of São Paulo, Brazil

2005 ◽  
Vol 57 (3) ◽  
pp. 321-325 ◽  
Author(s):  
M.C. Horta ◽  
A. Pinter ◽  
A. Cortez ◽  
R.M. Soares ◽  
S.M. Gennari ◽  
...  
Keyword(s):  
Spotted Fever ◽  
Sao Paulo ◽  
The State ◽  
Ctenocephalides Felis ◽  
Spotted Fever Group ◽  
São Paulo ◽  
Chain Reaction ◽  
Rickettsia Felis ◽  
Ctenocephalides Felis Felis ◽  
Polymerase Chain

Samples of 10 and 14 Ctenocephalides felis felis fleas were collected on dogs from Pedreira and Mogi das Cruzes municipalities, respectively, in the State of São Paulo, Brazil, for detection of Rickettsia spp. Individual fleas were submitted to Polymerase Chain Reaction targeting the 17-kDa and the 190-kDa (OmpA) genes of Rickettsiae. This later gene is specific for spotted fever group. Nine fleas from Pedreira (90%) and four fleas from Mogi das Cruzes (28%) were positive for the 17-kDa gene, and eight fleas from Pedreira (80%) and four from Mogi das Cruzes (28%) were positive for 190-kDa gene. The nucleotide sequence of the 190-kDa products of one flea from Pedreira and one flea from Mogi das Cruzes were 100% identical to each other, and when compared to the GenBank Data, they were 100% identical to the 190-kDa sequence of R. felis. This was the first report of its occurrence in the State of São Paulo.

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