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M F Thorel

Publications and source records attributed to M F Thorel.

At least 37 records · Page 2Linked to original sources
PubMed1990

Numerical taxonomy of mycobactin-dependent mycobacteria, emended description of Mycobacterium avium, and description of Mycobacterium avium subsp. avium subsp. nov., Mycobacterium avium subsp. paratuberculosis subsp. nov., and Mycobacterium avium subsp. silvaticum subsp. nov.

We performed a numerical taxonomy analysis of 38 Mycobacterium paratuberculosis and related mycobacterial strains, including wood pigeon mycobacteria; this analysis was based on 22 tests, which were selected for their potential discriminative value from a total of 51 tests studied and produced four well-defined clusters. Cluster 1 contained the M. paratuberculosis strains, including two strains isolated from Crohn's disease patients; cluster 2 contained Mycobacterium avium and Mycobacterium intracellulare reference strains; cluster 3 consisted of the wood pigeon mycobacteria; and the only strain in cluster 4 was M. paratuberculosis 316F, which is used for antigen and vaccine production. Strains in cluster 1 were mycobactin dependent even when they were subcultured, whereas strains in cluster 3 were unable to grow on egg medium and their growth was stimulated by pH 5.5. Growth stimulation by pyruvate, resistance to D-cycloserine (50 micrograms/ml), and alkaline phosphatase activity also were characteristics that were useful for discriminating between clusters 1 and 3. The results of previous DNA-DNA hybridization studies have demonstrated that M. avium Chester 1901, M. paratuberculosis Bergey et al. 1923, and the wood pigeon mycobacteria belong to a single genomic species, and we propose that the name of this species should be M. avium. On the basis of the results of previous genomic analyses based on restriction fragment length, the results of polymorphism studies, and DNA patterns determined by field inversion gel electrophoresis as well as the results of our phenotypic study, we propose that the species should be divided into subspecies which correspond to pathogenicity and host range characteristics.(ABSTRACT TRUNCATED AT 250 WORDS)

Mycobacterium avium↗
PubMed1990

[Endodermal sinus tumor. Histological changes induced by chemotherapy].

The case of a child affected at birth sacrococcygeal teratoma is reported. Twenty-eight months following surgical resection, the tumor relapsed locally and liver metastases occurred. A biopsy of the sacrococcygeal mass was performed and histologic examination proved it to be an endodermal sinus (yolk sac) tumor. Chemotherapy consisting of etoposide and high-dose carboplatin was started. When a second operation was performed the mass had disappeared and the macroscopically involved areas of liver were removed. Histologic examination demonstrated that the complete necrosis of the tumor was partially replaced by a fibrous scar tissue. The child underwent adjuvant chemotherapy and now is in complete remission fourteen months after the last operation.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

DNA polymorphism in Mycobacterium paratuberculosis, "wood pigeon mycobacteria," and related mycobacteria analyzed by field inversion gel electrophoresis.

Mycobacterium paratuberculosis strains, mycobacteria from patients suffering from Crohn's disease, "wood pigeon mycobacteria," and representatives of Mycobacterium avium-Mycobacterium intracellulare were compared by restriction endonuclease DraI digestion and field inversion gel electrophoresis. Characteristic profiles were seen for M. paratuberculosis, including isolates from patients suffering from Crohn's disease, for wood pigeon mycobacteria, and for M. avium-M. intracellulare serotypes 2, 16, 18, and 19. Two M. paratuberculosis strains used for vaccine production (St 18 and 316 F) presented patterns different from those of the other M. paratuberculosis strains. Strains St 18 yielded a pattern identical to that of the M. avium type strain serotype 2, whereas 316 F gave a unique pattern. The method developed in this study represents a useful taxonomic tool for the identification and classification of mycobacteria.

Animals↗
PubMed1989

Evidence that host-recycling of Mycobacterium avium preserves its ability to hinder macrophage killing functions.

The opportunistic pathogen Mycobacterium avium was selected as a model for the study of the bacterial cell envelope and resistance to macrophage killing functions. We hereby demonstrate that characteristic features of M. avium, e.g. existence of a polysaccharide-rich outer layer (POL), presence of a protective capsule also called electron-transparent zone (ETZ) around phagocytized bacteria, and inhibition of phagosome-lysosome fusions (PLF), were better expressed by bacteria recently isolated from infected rabbits than by bacteria subcultured in laboratory media. Our data appeared to confirm previous suggestions that M. avium regulatory mechanisms are such that during laboratory growth of these bacteria, synthesis of surface components which may be important concerning their virulence properties, is effectively diminished.

Animals↗
PubMed1989

Serologic and immunocytochemical analysis of the Mycobacterium avium cell envelope.

Whole cell sonicates of Mycobacterium avium ATCC 15769, and subcellular fractions (CYT, cytosol; CM, cytoplasmic membrane; CWS, delipidated cell wall skeleton; OL, native lipids; and SDS, sodium dodecylsulfate extract of whole cells) were injected into rabbits to produce corresponding antisera. Immunoelectrophoretic analysis and immunochemical observations using electron microscopy showed that few of the antigens synthetized intracellularly were exported and located in the bacterial outer layers, and that the outer layers contained wall specific antigens possibly in situ assembled.

Antibodies, Bacterial↗
PubMed1988

Characterization of distinct layers of the Mycobacterium avium envelope in respect of their composition by fatty acids, proteins, oligosaccharides and antigens.

The distribution of fatty acids, proteins, polysaccharides and antigens in subcellular fractions of Mycobacterium avium is described. Significant qualitative differences in the chemical composition of the various fractions have been used to further characterize the tripartite structure of the cell wall. In the outer dense layer (POL), in addition to previously described complex amphiphatic lipids, new oligosaccharides (lipooligosaccharides?) and a major glycoprotein were located; and it was found that tuberculostearic acid (TSA) esterified the phospholipids of this outerlayer. Judging from the data, it was proposed that the phospholipids formed a basic matrix monolayer in which other compounds of the POL intercalated. It was suggested that in an aqueous environment the hydrophobic ends of the phospholipids oriented to face the mycolic acid residues of the cell wall skeletons (or CWS) to form the 12 nm thick electron transparent layer. The purified CWS contained alpha-, keto-, and dicarboxylic mycolic acids; alanine, glutamic acid and diaminopimelic acid; and arabinose and galactose. Two additional nonidentified amino acids and an unidentified sugar were found in the CWS. Also, in the CWS the fatty acids: palmitic acid (21.8%), oleic acid (4.3%), stearic acid (9.2%) and TSA (4.3%), were detected. The main fatty acids detected in the cytoplasmic membrane (CM) were palmitic (20%), oleic (14.5%) and stearic (8.6%) acids. Mycolic acids and TSA were absent in the CM phospholipids. The major proteins of the CM (86, 40, and 26 Kd proteins) were distinct from the major proteins detected in the cytosol (CYT) fraction (43, 36, and 19 Kd proteins). A 58 Kd protein was present in both the CM and the CYT. The CYT and CM antigens were found absent in surface antigens extracted using sodium dodecyl sulphate (SDS).

Antigens, Bacterial↗
PubMed1987

Structure of the cell envelope of Mycobacterium avium.

In this report the cell wall of Mycobacterium avium is shown as a triple-layered structure where the outermost layer was stained by the ruthenium red staining for polysaccharides. The outermost layer hindered the diffusion of chemotherapeutic agents across the wall thus causing multiple drug-resistance by exclusion. The concerted electron microscopy and chemical analysis of chloroform-methanol and Triton X-100 extracts indicated that the outer layer was made of diverse amphiphil glycolipids (mycosides C, glycolipids, peptidolipids, phospholipids) that formed a matrix in which proteins were embedded. The examination of a spontaneous rough mutant indicated that mutations blocking the synthesis of one or several of the amphiphils must leave unsubstituted mycolic acid residues, thus causing surface hydrophobicity and roughness. Judging from our data, a model describing the overall cell envelope of M. avium was proposed. From the comparative analysis of M. avium, its spontaneous rough mutant, and its spheroplasts, some of the functions of the outermost layer were disclosed.

Antigens, Bacterial↗
PubMed1985

[Experimental paratuberculosis: biological diagnosis in calves inoculated with strains of mycobactin-dependent mycobacteria].

During an experiment on the pathogenicity of mycobactin-dependent mycobacteria strains for calf, the kinetics of antibody formation during infection was studied. The progress of cellular immunity was followed by examining delayed hypersensitivity using four allergens (bovine tuberculin HCSM, avian tuberculin HCSM, avian tuberculin PPD, and johnin PPD), and that of humoral immunity using complement fixation test and ELISA. Simultaneously, the elimination of bacilli in the faeces was examined. The excretion of bacilli, although intermittent, appeared to be the most demonstrative proof of infection: it could be shown at any stage of the disease. On the contrary, the delayed hypersensitivity using the avian tuberculin, and the serologic tests (the complement fixation test and ELISA), were positive only at defined periods of the disease: hypersensitivity reactions developed earlier than humoral reactions. The results obtained during these experiments confirmed that the mycobactin-dependent strains of "wood-pigeon" mycobacteria caused a disease in calves similar to the disease caused by Mycobacterium paratuberculosis.

Animals↗
PubMed1985

[Experimental pathogenicity of so-called atypical mycobacteria in mice, hamsters and meriones. Anatomo-pathological study].

Three animal species were used for the experimental pathogenicity of fourteen out of a total of thirty strains of atypical mycobacteria which were isolated from lymph nodes of healthy pigs in the surrounding area of Montevideo. White mice, hamsters and meriones were inoculated by intraperitoneal, intravenous or intracardiac routes. These animals were observed for either one year or until death, if death occurred during that year. Macroscopic and microscopic lesions were studied. Smears and cultures were also performed. This method led to a better knowledge of the pathogenicity of the following atypical mycobacteria species: Mycobacterium kansasii, MAIS complex and M. chelonae. It showed that some saprophyte strains belonging to terrae and vaccae complex were able to develop a pathogenicity. The hamster appeared to be the most sensitive animal.

Animals↗
PubMed1984

[Experimental paratuberculosis: pathogenicity of mycobactin-dependent mycobacteria strains to calves].

The pathogenicity for calves of two strains of wood-pigeon mycobacteria isolated in our laboratory, one strain isolated in the United Kingdom, one strain isolated from a Roe-deer in Denmark and three strains of M. paratuberculosis, were compared. Seven groups of four 3 to 4 week-old calves were infected by the intravenous route using 10(6) to 10(9) viable units. They were slaughtered one year after the exposure or earlier if their state required it. The macroscopic and microscopic lesions and cultures from the mesenteric lymph nodes, ileon and caecum were studied. At necropsy, the post-mortem findings were hardly significant. However, the histopathological studies showed lesions identical to the classical aspects of paratuberculosis in cattle, both in animals inoculated with M. paratuberculosis and those inoculated with wood-pigeon mycobacteria. The isolation of the bacteria showed that all animals were infected. The experimental infection was able to reproduce a disease resembling paratuberculosis with M. paratuberculosis (except the strain 2103) and with wood-pigeon mycobacteria, but it has not been able to distinguish the disease caused by M. paratuberculosis from the one caused by wood-pigeon mycobacteria.

Animals↗
PubMed1980

Isolation of Mycobacterium africanum from monkeys.

The first isolation of M. africanum from monkeys is reported. This finding leads the author to discuss the origin of the infection in monkeys, and to underline the potential public health hazard that animals may present for humans.

Animals↗
PubMed1976

[Several strains of Mycobacterium paratuberculosis: biochemical characteristics and allergic activity].

Judged from its biochemical properties and antigenic structure, Mycobacterium paratuberculosis is related to M. avium. When M. paratuberculosis was compared to B.C.G., several essential differences, were found that allowed their clear separation, within Runyon's Group III, M. paratuberculosis is differentiated by its biochemical properties as shown in the following table : (formula: see text). The allergic response of a guinea pig infected with M. paratuberculosis was stronger when an avium sensitine was used that when a bovine tuberculine was used.

Animals↗
PubMed1976

[Action of 4 percent sulfuric acid on various species of mycobacteria].

The action of treatment with 4 p. cent sulphuric acid for 10 minutes, was tested on 13 strains of mycobacteria. Rapidly growing mycobacteria, e.g. M. diernhoferi, M. chelonei M. abscessus, M. Fortuitum, proved much more sensitive than slowly growing mycobacteria, e.g. M. xenopi, M, scrofulacem, M. kansaii, M. avium, M. marinum, BCG, M. tuberculosis and M. Bovis. We observed the persistance of a certain number of viable bacteria in spite of a duration of contact of 120 minutes, Albumin in the culture medium used presented a protective effect together with the high concentration in bacteria.

Albumins↗
PubMed1976

[Use of two dimensional immunoelectrophoretic method in the study of the antigenic relationships of "Mycobacterium simiae" and "M. habana" (author's transl)].

Following the cultural, biochemical and serologic studies reported elsewhere, it was thought of interest to investigate the antigenic structure of these strains. In the present work, sonicated suspensions of the bacteria were used as antigens, together with rabbit immune serum antibodies. The optimal conditions to obtain the largest number and the sharpest lines possible, were established. In this manner, we were able to obtain on two dimensional electrophoresis patterns were obtained. Using an anti-M. habana 4238 antiserum, 36 lines of precipitation were obtained with M. habana 4238, 41 lines with M. simiae 29 and 29 lines with for M. simiae 59-IX-7. Subsequently, identity tests were performed to verify the occurrence of were common antigens. These tests revealed such commons antigens in all the three strains. The comparison between M. habana and M. simiae 29 showed the occurence of at least one Precipitation line, that is characteristic of M. habana. These results appear to agree with those of Meissner, who obtained a small amount of anti-M. habana specific agglutinins. However, this worker did not believe that this was sufficient evidence to separate M. simiae 29 from M. habana. The antigenic differences between M. habana and M. simiae 59-IX-7 are more significant and appear to justify their differentiation into 2 serotypes: M. habana 4238 and M. simiae 29 being of serotype 1, M. simiae 59-IX-7 of serotype 2. The difficulties experienced in the separation of the antigenic fractions in the immunoelectrophoretic diagrams, led to consider the purification of the antigens and then to attempt to isolate the specific antigenic fractions.

Antigens, Bacterial↗