RESUMEN
The effects in vitro of 4 purified lipopolysaccharide (LPS) preparations from Rickettsiae on platelets and leucocytes were studied in rabbits and in man. All LPS induced aggregation in rabbit platelet-rich plasma but to differing degrees. This activity was abolished by inactivation of complement. None of the preparations induced aggregation of human platelets. Both rabbit and human leucocytes, when incubated with each of the rickettsial LPS preparations, generated a potent procoagulant activity (tissue factor). These findings add further support to the concept that rickettsial LPS behave as typical LPS from gram-negative bacteria and may be relevant to the understanding of the mechanism(s) responsible for triggering intravascular coagulation in rickettsial diseases.
Asunto(s)
Leucocitos/efectos de los fármacos , Lipopolisacáridos/farmacología , Agregación Plaquetaria/efectos de los fármacos , Rickettsia/análisis , Tromboplastina/metabolismo , Animales , Coxiella/análisis , Escherichia coli/análisis , Humanos , Leucocitos/metabolismo , Conejos , Rickettsia typhi/análisisRESUMEN
The A.A. have examined by Limulus endotoxin assay some LPS preparations from R. typhi, R. slovaka, C. burnetti phase I and II, as a demonstration of endotoxicity. All the preparations tested were able to gel the Limulus amoebocyte lysates, even if to a different degree of reactivity. The results add credibility to the hypothesis that LPS from Rickettsiaceae can represent at least in part the pathogenetic mediators of some manifestations described in Rickettsiosis; however, without endotoxin assay in the blood of patients, one cannot assume to this be true.
Asunto(s)
Prueba de Limulus , Lipopolisacáridos/análisis , Rickettsiaceae/análisis , Coxiella/análisis , Rickettsia typhi/análisisRESUMEN
A lipophilic thermostable lipopolysaccharide (LPS) complex was isolated by phenol extraction from purified suspensions of the typhus group rickettsiae. The LPS complex is antigenic and possesses some endotoxic properties such as toxicity for actinomycin D-treated mice, pyrogenicity for rabbits and guinea pigs, ability to elicit hypothermia in white rats and local Schwartzman reaction and active cutaneous anaphylaxis in rabbits.
Asunto(s)
Endotoxinas , Lipopolisacáridos , Polisacáridos Bacterianos , Rickettsia prowazekii/análisis , Rickettsia typhi/análisis , Rickettsia/análisis , Anafilaxia/inducido químicamente , Animales , Endotoxinas/toxicidad , Fiebre/inducido químicamente , Cobayas , Lipopolisacáridos/inmunología , Lipopolisacáridos/toxicidad , Ratones , Polisacáridos Bacterianos/inmunología , Polisacáridos Bacterianos/toxicidad , Conejos , Fenómeno de Shwartzman/inducido químicamenteRESUMEN
Purified radioactive rickettsiae were obtained from irradiated and cycloheximide-inhibited L cells, and their proteins were analyzed by polyacrylamide gel electrophoresis. Rickettsial species could be distinguished by comparing the relative mobilities of constituent proteins after migration of two differentially labeled preparations in a single gel. Distinct differences were observed in gel patterns of rickettsiae from the typhus and spotted fever groups, as well as with different species within a group. Rickettsial organisms causing murine and epidemic typhus were clearly distinguished, as were the causative agentsof boutonneuse fever and rickettsialpox. The use of both internal and external molecular weight standards allowed molecular weight estimates for 19 proteins from both Rickettsia prowazekii and Rickettsia conorii. A flexible system for designating rickettsial proteins is proposed that lends itself to modification as more detailed analysis progresses.
Asunto(s)
Proteínas Bacterianas/análisis , Rickettsia/análisis , Aminoácidos/metabolismo , Cicloheximida/farmacología , Células L/metabolismo , Peso Molecular , Rickettsia prowazekii/análisis , Rickettsia rickettsii/análisis , Rickettsia typhi/análisis , Fiebre Maculosa de las Montañas Rocosas/microbiología , Especificidad de la Especie , Tifus Epidémico Transmitido por Piojos/microbiología , Rayos UltravioletaRESUMEN
There is a small but distinct difference in DNA base composition between the typhus and spotted fever groups of rickettsiae. The molar percentages of guanine plus cytosine for Rickettsia prowazeki, R. typhi, and R. canada are approximately 30, for R. rickettsi, R. conori, and R. akari they are about 32.5. The percentage for trench fever rickettsia, Rochalimaea quintana, is 38.6.