Rickettsial hemolysis: rapid method for enumeration of metabolically active typhus rickettsiae.

Rickettsial effects on leukotriene and prostaglandin secretion by mouse polymorphonuclear leukocytes.

Typhus rickettsiae were incubated with mouse exudative polymorphonuclear leukocytes (PMN), and supernatants were examined for leukotriene B4 (LTB4) and prostaglandin E2 (PGE2) secretion by radioimmunoassay. PMN incubated with native rickettsiae secreted significantly more LTB4 and PGE2 than did those incubated with buffer alone. Autacoid secretion was dependent on both the time of PMN incubatio...

The Phenomenon of in Vitro Hemolysis Produced by the Rickettsiae of Typhus Fever, with a Note on the Mechanism of Rickettsial Toxicity in Mice

Suspensions of yolk sac infected with rickettsiae of murine or of epidemic typhus, and indeed suspensions of liver or peritoneal washings from cotton rats infected with these organisms, when the suspensions contain a sufficient concentration of living rickettsiae, possess the capacity to hemolyze, in vitro, red cells of rabbit or sheep origin. Under the same conditions such material did not cau...

The Phenomenon of in Vitro Hemolysis Produced by the Rickettsiae of Typhus Fever, with a Note on the Mechanism of Rickettsial Toxicity in Mice by Delphine

Evaluation of a PCR assay for quantitation of Rickettsia rickettsii and closely related spotted fever group rickettsiae.

A spotted fever rickettsia quantitative PCR assay (SQ-PCR) was developed for the detection and enumeration of Rickettsia rickettsii and other closely related spotted fever group rickettsiae. The assay is based on fluorescence detection of SYBR Green dye intercalation in a 154-bp fragment of the rOmpA gene during amplification by PCR. As few as 5 copies of the rOmpA gene of R. rickettsii can be ...

Differentiation of rickettsiae by groEL gene analysis.

The nucleotide sequences (534 to 546 bp) of the groEL gene, which encodes the 60-kDa heat shock protein GroEL, from 15 rickettsial strains were determined and compared. In the phylogenetic tree created by the unweighted pair group method with arithmetic averages and the neighbor-joining method, rickettsial strains could be distinguished from Ehrlichia strains. Five spotted fever group strains, ...