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At least 37 records · Page 2Linked to original sources
PubMed2004

A reovirus of the fungus Cryphonectria parasitica that is infectious as particles and related to the coltivirus genus of animal pathogens.

RNA viruses of filamentous fungi fall into two broad categories, those that contain double-stranded RNA (dsRNA) genomes in rigid particles and those that are more closely related to positive-sense, single-stranded RNA viruses with dsRNA replicative intermediates found within lipid vesicles. Effective infectivity systems have been described for the latter, using RNA transcripts, but not for the former. We report the characterization of a reovirus from Cryphonectria parasitica, the filamentous fungus that causes chestnut blight disease. The virus substantially reduces the virulence of the fungus and results in dramatically altered colony morphology, as well as changes in other associated fungal traits, relative to the virus-free isogenic strain. Virus particles from infected mycelium contained 11 segments of dsRNA and showed characteristics typical of the family Reoviridae. Sequences of the largest three segments revealed that the virus is closely related to the Coltivirus genus of animal pathogens, which includes the human pathogen Colorado tick fever virus. The introduction of purified virus particles into protoplasts from virus-free isolates of the fungus resulted in a newly infected mycelium with the same morphology and virus composition as the original virus-infected isolate. This represents the completion of Koch's postulates for a true dsRNA virus from a filamentous fungus and the description of a definitive fungal member of the family Reoviridae.

Ascomycota↗
PubMedDate not supplied

Evaluation of phenotypic markers associated with pathogenicity in the genus Listeria.

A total of 130 Listeria strains were tested in order to evaluate lecithinase production and capacity for Congo red adsorption as markers of pathogenicity. The strains were identified according to acid production from sugars and by the CAMP test and the data were correlated with the ability to produce keratoconjunctivitis in guinea pigs. L. monocytogenes cultures presented 51.8% and 88.8% positivity rates for Congo red adsorption and lecithinase production, respectively, whereas 80.8% and 100% for L. innocua cultures were negative for the two test, respectively.

Animals↗
PubMedDate not supplied

[The characteristics of new species of pathogenic microorganisms in the genus Francisella].

The comparative study of newly discovered pathogenic bacteria of the genus Francisella was carried out with the use of a complex of microbiological and serological methods. While having great similarity to the causative agent of tularemia, F. novicida, F. novicida-like bacteria and F. philomiragia had lesser growth requirements, some specific morphological and structural features, were capable of fermenting sucrose and exhibited low pathogenicity to experimental animals. The strains under study proved to be virulent with regard to golden hamsters, who were for this reason proposed as an adequate model for the isolation of these bacteria from environmental objects and pathological material obtained from patients. The use of immunoblotting made it possible to find out that all Francisella species had protein antigens, similar to their electrophoretic mobility and serological activity.

Animals↗
PubMed1997

The expanding genus of Helicobacter: pathogenic and zoonotic potential.

The microbial flora of stomachs of humans and animals have been the focus of considerable research since the discovery that Helicobacter pylori in humans caused a variety of gastric diseases. Other Helicobacter species have now been isolated from the stomachs of various mammals, including dogs, cats, ferrets, pigs, monkeys, and cheetahs, all of which are associated with various degrees of gastritis in their hosts. Helicobacter species have also been isolated from the intestinal tracts of humans, animals, and birds. Helicobacter species have not only been isolated from intestines of mice but have, in addition, been isolated from diseased livers of inbred and outbred mice, and one of these, H hepaticus is linked to liver tumors. H canis and H pullorum isolated from dogs and chickens, respectively, have also been cultured from feces of diarrheic humans. H fennelliae and H cinaedi are two additional helicobacters primarily associated with lower bowel disease in immunocompromised humans. To date, there are at least 13 formally named species of the new genus, Helicobacter, the majority being proven or suspected gastrointestinal or hepatic pathogens. Several of these helicobacters have zoonotic potential as well. It is predicted that additional Helicobacter species will be identified, and they, too, may be important pathogens in humans and animals.

Acinonyx↗
PubMed2000

Dictyostelium discoideum: a new host model system for intracellular pathogens of the genus Legionella.

The soil amoeba Dictyostelium discoideum is a haploid eukaryote that, upon starvation, aggregates and enters a developmental cycle to produce fruiting bodies. In this study, we infected single-cell stages of D. discoideum with different Legionella species. Intracellular growth of Legionella in this new host system was compared with their growth in the natural host Acanthamoeba castellanii. Transmission electron microscopy of infected D. discoideum cells revealed that legionellae reside within the phagosome. Using confocal microscopy, it was observed that replicating, intracellular, green fluorescent protein (GFP)-tagged legionellae rarely co-localized with fluorescent antibodies directed against the lysosomal protein DdLIMP of D. discoideum. This indicates that the bacteria inhibit the fusion of phagosomes and lysosomes in this particular host system. In addition, Legionella infection of D. discoideum inhibited the differentiation of the host into the multicellular fruiting stage. Co-culture studies with profilin-minus D. discoideum mutants and Legionella resulted in higher rates of infection when compared with infections of wild-type amoebae. Because the amoebae are amenable to genetic manipulation as a result of their haploid genome and because a number of cellular markers are available, we show for the first time that D. discoideum is a valuable model system for studying intracellular pathogenesis of microbial pathogens.

Acanthamoeba↗
PubMedDate not supplied

Lipopolysaccharides of bacterial pathogens from the genus Yersinia: a mini-review.

This review summarizes the state of knowledge on the composition and structure of the lipopolysaccharides (LPS) from three species of Yersinia known to produce disease in humans: Y. pseudotuberculosis, Y. enterocolitica and Y. pestis. We also mention recent data on the genome sequence of Yersinia pestis and the role of LPS in relation to the virulence of this bacteria.

Carbohydrate Sequence↗
PubMedDate not supplied

Studies concerning the hemagglutinant activity of some pathogenic and opportunistic pathogenic strains of genus Vibrio.

1606 bacterial strains, belonging to Vibrio genus (189 V. cholerae 0 : 1; 1091 V. cholerae nongroup 0 : 1 and 205 V. halophilic strains) of different sources of isolation, were studied, concerning their hemagglutinating behaviour to 5 different animal red blood cells (human, bovine, chicken, African green monkey and guinea pig) in mannose/fucose presence/absence. The study aimed to establish the spectrum of their hemagglutinating activity as well as any possible correlation between the source of isolation, serogroup etc and the HA-type/subtype. Mannose/fucose sensitive as well as mannose/fucose resistant hemagglutinins were exhibited by the different tested strains. As unknown behaviour, a noticeable hemagglutination only in the carbohydrate presence was recorded. The HA-types and subtypes in 861 V. cholerae nongroup 0 : 1 tested strains are presented.

Animals↗
PubMed2001

Development of a strain-specific SCAR marker for the detection of Trichoderma atroviride 11, a biological control agent against soilborne fungal plant pathogens.

The genus Trichoderma includes biocontrol agents (BCAs) effective against soilborne plant pathogenic fungi. Several potentially useful strains for biological control are difficult to distinguish from other strains of Trichoderma found in the field. So, there is a need to find ways to monitor these strains when applied to natural pathosystems. We have used random amplified polymorphic DNA (RAPD) markers to estimate genetic variation among sixteen strains of the species T. asperellum, T. atroviride, T. harzianum, T. inhamatum and T. longibrachiatum previously selected as BCAs, and to obtain fingerprinting patterns. Analysis of these polymorphisms revealed four distinct groups, in agreement with previous studies. Some of the RAPD products generated were used to design specific primers. Diagnostic PCR performed using these primers specifically identify the strain T. atroviride 11, showing that DNA markers may be successfully used for identification purposes. This SCAR (sequence-characterised amplified region) marker can clearly distinguish strain 11 from other closely related Trichoderma strains.

Genetic Markers↗
PubMed1978

[Studies on the viability of pathogenic amebae of the genus Naegleria in water of different sources (author's transl)].

Water specimens taken from the public water supply (A), a swimming-pool (B), and an inland lake (C) were infected with pathogenic amebae of the genus Naegleria (strain TY/Richmond). The specimens were stored at various temperatures for different periods. The water was then filtered and examined for naegleriae by animal inoculation. The results summarized in table 1 indicate that pathogenic naegleriae are viable at least for some weeks in warm tap and natural waters. Water from indoor swimming-pools however, may be a less suitable medium for the viability of pathogenic naegleriae.

Amoeba↗
PubMed2004

High-throughput detection of pathogenic yeasts of the genus trichosporon.

The need for a rapid and accurate method for the detection of fungal pathogens has become imperative as the incidence of fungal infections has increased dramatically. Herein, we tested the Luminex 100, a novel flow cytometer, for the detection of the medically important genus Trichosporon. This genus was selected as our proof-of-concept model due to the close phylogenetic relationship between the species. The method, which is based on a nucleotide hybridization assay, consists of a combination of different sets of fluorescent beads covalently bound to species-specific capture probes. Upon hybridization, the beads bearing the target amplicons are classified by their spectral addresses with a 635-nm laser. Quantitation of the hybridized biotinylated amplicon is based on fluorescence detection with a 532-nm laser. We tested in various multiplex formats 48 species-specific and group-specific capture probes designed in the D1/D2 region of ribosomal DNA, internal transcribed spacer regions, and intergenic spacer region. Species-specific biotinylated amplicons were generated with three sets of primers to yield fragments from the three regions. The assay was specific and fast, as it discriminated species differing by 1 nucleotide and required less than 50 min following amplification to process a 96-well plate. The sensitivity of the assay allowed the detection of 10(2) genome molecules in PCRs and 10(7) to 10(8) molecules of biotinylated amplification product. This technology provided a rapid means of detection of Trichosporon species with the flexibility to identify species in a multiplex format by combining different sets of beads.

Animals↗