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G Baranton

Publications and source records attributed to G Baranton.

At least 73 records · Page 4Linked to original sources
PubMed1992

Cloning of dapD, aroD and asd of Leptospira interrogans serovar icterohaemorrhagiae, and nucleotide sequence of the asd gene.

Metabolites such as diaminopimelate and some aromatic derivatives, not synthesized in mammalian cells, are essential for growth of bacteria. As a first step towards the design of a new human live vaccine that uses attenuated strains of Leptospira interrogans, the asd, aroD and dapD genes, encoding aspartate beta-semialdehyde dehydrogenase, 3-dehydroquinase and tetrahydrodipicolinate N-succinyltransferase, respectively, were cloned by complementation of Escherichia coli mutants. The complete nucleotide sequence of the asd gene was determined and found to contain an open reading frame capable of encoding a protein of 349 amino acids with a calculated Mr of 38,007. Comparison of this deduced L. interrogans aspartate beta-semialdehyde dehydrogenase amino acid sequence with those of the same enzyme from Saccharomyces cerevisiae and Corynebacterium glutamicum revealed 46% and 36% identity, respectively. By contrast, the identity between the L. interrogans enzyme and the Streptococcus mutans or E. coli enzymes was less than 31%. Highly conserved sequences within aspartate semialdehyde dehydrogenase from the five organisms were observed at the amino and carboxyl termini, and around the cysteine of the active site.

Acyltransferases↗
PubMed1992

No evidence for a spirochaetal origin of localized scleroderma.

We looked for evidence of a Borrelia infection in 15 patients with morphoea. We were not able to detect antibodies to Borrelia burgdorferi in any of these 15 patients. None of the 14 skin biopsies examined by immunohistochemistry showed evidence of spirochaetes. Skin biopsies were cultured in 10 patients. All were negative. These results do not support a spirochaetal origin of localized scleroderma.

Adolescent↗
PubMed1992

Population genetic analysis of Borrelia burgdorferi isolates by multilocus enzyme electrophoresis.

Fifty Borellia burgdorferi strains isolated from humans and ticks in Europe and the United States were analyzed by multilocus enzyme electrophoresis. Eleven genetic loci were characterized on the basis of the electrophoretic mobilities of their products. Ten loci were polymorphic. The average number of alleles per locus was 5.9, with a mean genetic diversity of 0.673 among electrophoretic types (ETs). The strains were grouped into 35 ETs constituting three main divisions (I, II, and III) separated at a genetic distance greater than 0.75. Divisions I, II, and III contained 13, 6, and 16 ETs, respectively. These findings, together with previous data from DNA hybridization and restriction enzyme analysis of rRNA genes, suggest that divisions I, II, and III may represent three distinct genomic species. All three divisions contained human clinical ETs. However, in division I, which includes the ET of the type strain of B. burgdorferi, the human pathogenic ETs constituted a single clone. The ETs of division I were from west-central Europe and the United States, whereas divisions II and III contained ETs from west-central and northern Europe but not from the United States. Finally, our data show that the genetic structure of B. burgdorferi populations is clonal.

Alleles↗
PubMed1992

Pulsed-field gel electrophoresis of NotI digests of leptospiral DNA: a new rapid method of serovar identification.

Fingerprints for 72 reference serovar strains of pathogenic Leptospira spp. were obtained by pulsed-field gel electrophoresis (PFGE) following NotI restriction digests of the chromosome. These strains included the serovar reference strains of serogroups Australis, Ballum, Bataviae, Grippotyphosa, Panama, Pomona, and Pyrogenes. Sixty-four serovars could be identified by a unique NotI restriction profile. The remaining serovars were differentiated by chromosomal digestion with SgrAI. These included four serovars from serogroup Australis, two serovars from serogroup Ballum, and two serovars from serogroup Bataviae. Thirteen of 18 recent clinical isolates identified by microagglutination test and cross-adsorption procedure were correctly typed by PFGE. The results indicate that PFGE, which is considerably more rapid than serology, should be useful for identification and epidemiological studies.

Animals↗
PubMed1992

Polymerase chain reaction for detection of Leptospira spp. in clinical samples.

A sensitive assay for Leptospira spp., the causative agent of leptospirosis, was developed on the basis of the polymerase chain reaction (PCR). A 331-bp sequence from the Leptospira interrogans serovar canicola rrs (16S) gene was amplified, and the PCR products were analyzed by DNA-DNA hybridization by using a 289-bp fragment internal to the amplified DNA. Specific PCR products also were obtained with DNA from the closely related nonpathogenic Leptospira biflexa but not with DNA from other spirochetes, such as Borrelia burgdorferi, Borrelia hermsii, Treponema denticola, Treponema pallidum, Spirochaeta aurantia, or more distant organisms such as Escherichia coli, Staphylococcus aureus, Mycobacterium tuberculosis, and Proteus mirabilis. The assay was able to detect as few as 10 bacteria. Leptospira DNA was detected in urine from experimentally infected mice. In addition, the test was found to be suitable for diagnosing leptospirosis in humans. Cerebrospinal fluid and urine from patients with leptospirosis were positive, whereas samples from control uninfected patients were negative.

Adolescent↗
PubMed1992

Occurrence of severe leptospirosis in a breeding colony of squirrel monkeys.

Although experimental leptospirosis has been studied in various species of monkeys, the occurrence of acute leptospirosis in a population of nonhuman primates is uncommon. We report on a number of severe cases of icterohemorrhagic leptospirosis that appeared in the squirrel monkey (Saimiri sciureus) colony of 109 animals at the Institute Pasteur in French Guiana. Initially, 11 animals had acute illness, with jaundice and a hemorrhagic syndrome, leading to 10 deaths. Two Leptospira interrogans strains were isolated from blood cultures of sick monkeys, and one was isolated from the urine of a rat trapped in the breeding park. All three belonged to serovar copenhageni, and tests using monoclonal antibodies showed that these three strains were extremely similar. In the following weeks, five pregnant female monkeys had miscarriages; two of them had antibodies against the Icterohaemorrhagiae serogroup. An epidemiologic study conducted on the 93 remaining animals demonstrated a seropositivity rate of 26% (microagglutination test [MAT] titer greater than or equal to 100) primarily for the Icterohaemorrhagiae serogroup, but also for the Ballum, Grippotyphosa, Sejroe, and Panama serogroups. In addition, 12% showed lower MAT titers (50) for the same serogroups. Lastly, recently trapped feral squirrel monkeys were shown to have agglutinins against the Grippotyphosa and Sejroe serogroups. A vaccine, which was prepared from one of the strains isolated, was used in addition to antibiotic prophylaxis to control the enzootic disease. This confirms that the squirrel monkey is highly susceptible to icterohemorrhagic leptospirosis and is probably receptive to other serogroups, and that this animal may be useful in studying experimental leptospirosis and for testing new human vaccines.

Acute Disease↗
PubMed1992

[Three bacterial species associated with Lyme borreliosis. CLinical and diagnostic implications].

DNAs from various Borrelia associated with Lyme disease were reciprocally hybridized. This genomic taxonomy method showed that Lyme disease agent comprised three genomic species. Two species could be differentiated by phenotypic characters as major proteins molecular weights and monoclonal antibodies reactivity. Western-blot with sera from patients suffering from different clinical forms of Lyme disease: arthritis, meningoradiculitis and Acrodermatitis Chronicum Atrophicans showed that each of these evolutive forms was preferentially associated with one of the species, respectively: Borrelia burgdorferi sensu stricto, Borrelia garinii and Borrelia group VS 461. Furthermore, geographical repartition of these three species was heterogeneous. B. burgdorferi sensu stricto seems to be the only one present in the United States of America, whereas it coexists in Europe mainly with B. garinii in Western Europe and Borrelia group VS 461 in Northern Europe.

Borrelia↗
PubMed1991

Genome conservation in isolates of Leptospira interrogans.

Reference strains for each of the 23 serogroups of Leptospira interrogans yielded different pulsed-field gel electrophoresis patterns of NotI digestion products. This was also the case for the 14 serovars belonging to serogroup Icterohaemorrhagiae (with one exception). The NotI restriction patterns of 45 clinical leptospiral isolates belonging to serovar icterohaemorrhagiae were analyzed and compared with those of type strains. No differences were observed between isolates from countries of different continents, namely, France, French Guiana, New Caledonia, and Tahiti. The pattern was indistinguishable from that of the reference strain of serovar icterohaemorrhagiae.

Biological Evolution↗
PubMed1991

[Seroepidemiological study of human leptospirosis at Reunion Island].

In order to evaluate the prevalence of human leptospirosis in Reunion island and to identify possible risk factors, a study was realised on a representative population sample of 3.338 persons. The prevalence of leptospirosis, diagnosed by ELISA and confirmed by Micro Agglutination Test, was 1.1%. Male predominance and higher prevalence in rainy parts of the island, were confirmed. It has not been possible to display risk factors such as housing conditions or professional exercise. The serological repartition showed not only icterohaemorrhagiae serovar, but also canicola, panama and sejroe, especially in women. These results, compared with clinical studies (showing nearly exclusive male repartition, in agricultural workers, due to icterohaemorrhagiae serovar), confirm the double look of human leptospirosis in Reunion island: clinical leptospirosis, severe, concerning males, often countrymen, due to icterohaemorrhagiae serovar, and infraclinical leptospirosis, concerning principally females, which is a domestic illness, due to other serovars.

Adolescent↗
PubMed1991

Taxonomy of Borrelia spp.

An increasing number of phenotypically heterogeneous borrelia isolates have been obtained by culture. Genetic analysis of some of them suggest that a reorganisation in delineation of the different species within the genus Borrelia may be necessary. Specifically increasing numbers of variants phenotypically different from the American type strain of B. burgdorferi have been described. In this workshop experts have discussed phenotypic and genotypic characters for (a) differentiation of B. burgdorferi strains from other borrelia and from treponemes, (b) characterization of B. burgdorferi isolates at the subspecies level. Ultrastructure was discussed by K. Hovind-Hougen, antigen structure by B. Wilske and genotypic characters by G. Baranton, A. G. Barbour, R. C. Johnson and V. Preac-Mursic. J. F. Anderson discussed differences between strains isolated from a wide range of vectors and hosts in North America. The outcome of the workshop was that B. burgdorferi may comprise different genomic species which however share common epitopes recognized by certain monoclonal antibodies. At the subspecies level a broad heterogeneity was demonstrated using methods as restriction endonuclease analysis, hybridization with whole B. burgdorferi-DNA or specific probes as well as plasmid analysis. A serotyping system based on monoclonal antibody reactivity against the outer surface protein OspA was proposed. A comparison of the different typing methods is impaired by use of different strains for analysis. In the future a broad variety of phenotypically different and defined strains need to be analysed for genotypic clusters and later on reexamined for phenotypic characters. To accomplish this close cooperation of different research groups is necessary.

Animals↗
PubMed1990

rRNA gene restriction patterns of Leptospira: a molecular typing system.

A total of 67 serovar reference strains and 7 isolates belonging to the genus Leptospira were characterized by ribosomal ribonucleic acid (rRNA) gene restriction patterns. Fifty patterns were observed. Strains belonging to different genomic species always gave different patterns. However, genomic species were subdivided into several patterns. Forty-three serovars gave a specific pattern. Some serovars could not be separated by rRNA gene restriction patterns: strains of serovars icterohaemorrhagiae, copenhageni, lai, pyrogenes and jalna gave pattern 1; serovars birkini, mankarso and wolffi gave pattern 4; serovars canicola, gem, hebdomadis, pomona and hardjo (strain hardjoprajitno) gave pattern 12; serovars valbuzzi and zanoni gave pattern 14; serovars jonsis, malaya and sumneri gave pattern 16; serovars arborea, ballum, castellonis and kenya gave pattern 35; and serovars borincana and shermani gave pattern 43. These data provide the bases for a molecular typing system for the genus Leptospira.

Bacterial Typing Techniques↗
PubMed1990

Two genomic species in Borrelia burgdorferi.

A total of 13 Borrelia burgdorferi strains (responsible for Lyme borreliosis) and representatives of 3 other Borrelia species (B. hermsii, B. parkeri, B. turicatae) associated with relapsing fever were studied by DNA/DNA hybridization and rRNA gene-restriction patterns. Two genomic DNA hybridization groups were observed which could be differentiated by rRNA gene-restriction patterns. Moreover, the number and size of restriction fragments suggest the existence of a single set of 16 and 23 S rRNA genes in Borrelia.

Borrelia burgdorferi Group↗
PubMed1990

Cloning of genes required for amino acid biosynthesis from Leptospira interrogans serovar icterohaemorrhagiae.

Leptospira interrogans belongs to a large family of important pathogens, which is part of the order Spirochaetales, a distinct group of eubacteria. In order to obtain a better understanding of the genetic organization of this species, we have constructed a DNA library of the serovar icterohaemorrhagiae, using the Escherichia coli vector pUC13. We have isolated Leptospira DNA fragments containing the genetic information required to complement strains of E. coli with defects in proline and leucine biosynthesis. While a 3.9 kb fragment which complemented proA also complemented proB, a 15 kb fragment complementing leuB could not complement other leu mutations. The L. interrogans origin of the cloned DNA fragments was confirmed by DNA-DNA hybridization. The hydridization was specific to the pathogenic species and was not seen with the saprophytic species L. biflexa.

Amino Acids↗
PubMed1990

[Leptospirosis in Mayotte].

We have got 42 leptospirosis cases from 1984 to 1989, in a retrospective study. The annual incidence is now, in a very high level (3.8/10,000 pers.). This rapid increasing is function of new diagnostics facilities. The leptospirosis epidemiology is not different from anywhere else in tropical countries, but the complicated cases are an important problem in public health in the island. The actual development of collective hygienic equipment is indispensable for any progress.

Adult↗
PubMed1989

[Classification of spirochetes infecting man].

The systematics od spirochetes must from now own fulfil the genomic criteria recently laid down. Formerly, these parasites were classified on the basis of various phenotypic features, among which the pathogenicity and epidemiological criteria played the predominant role. At present, the order of Spirochaetales is divided into two families: Spirochaetaceae and Leptospiraceae. Two of the four genera of Spirochaetaceae, Treponema and Borrelia, include species that are pathogenic to man. Among Leptospiraceae, only one genus, Leptospira, has pathogenic species. The phenotypic characteristics of the various taxons are detailed, the role of each actor (causative agent, vector, reservoir) in the main pathological complexes and the progress of genotypic studies are briefly described.

Humans↗
PubMed1989

Linear chromosome of Borrelia burgdorferi.

The DNA organization of several European and American isolates of Borrelia burgdorferi, the aetiological agent of Lyme disease, was analysed in pulse-field agarose gel electrophoresis. The results of in situ cell lysis in agarose plugs demonstrated a unique arrangement for the DNA of this spirochete. The chromosome of Borrelia behaved as a eukaryotic linear chromosome with a size of around 1,000 kb. The genome also comprised several circular and linear plasmids which varied in size from 15 to 60 kb.

Borrelia burgdorferi Group↗