PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “pathogenic genus”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed1986

Cleavage of immunoglobulins by pathogenic yeasts of the genus Candida.

The yeast-like fungi Candida albicans and Candida tropicalis are opportunistic pathogens which are distinguished from less virulent yeasts by the secretion of acid proteases. Candida proteases cleave various human immunoglobulins including IgA2 and secretory immunoglobulins. They cover a wider range of substrates than bacterial IgA-proteases, and possibly play a role in the pathogenesis of thrush and deep candidosis.

Candida↗
PubMed1996

Listeria monocytogenes--aspects of pathogenicity.

The genus Listeria includes different species of ubiquitary present gram-positive rod shaped bacteria. The species Listeria monocytogenes causes severe diseases like meningitis and meningoencephalitis in humans. Additional groups of syndromes associated with this microorganism are the listeriosis of the pregnant woman, mostly appearing as an abortion or septic premature birth and the meningitis of the newborn. Transmission of Listeria may occur on the oral route due to infected food like raw milk and cheese, raw meat or soil contaminated food like prepacked salads, respectively. The understanding of Listeria virulence was improved by different investigations employing cell cultures and molecular methods like knockout of genes encoding potential virulence factors. Nowadays the procedure of infection of cells is divided in four different parts: internalisation, escape from intracellular vacuole, nucleation of actin filaments and cell-to-cell spread. So called Internalins are produced by Listeria and are obviously needed for cell invasion. Listeria could escape intracellular vacuoles producing a hemolysin, Listeriolysin O, and proliferate inside the host cells. The surface bounded protein Actin A mediates the contact to the actin filament system of the host cell. This is important for the intracellular spread of Listeria. In the next step a cell-to-cell spread supported by phospholipase and lecithinase occurs. Despite the high incidence of contaminated food only a little incidence of listeriosis is observed. This may be explained in an indirect vaccination due to less virulent strains. However, the immune response of patients even with well documented listeriosis may be poor and causes false negative serological results sometimes. In this paper the know virulence factors of the interesting species L. monocytogenes are demonstrated and the course of infection is discussed.

Female↗
PubMedDate not supplied

[Ecological and epidemiological relationships between Sporothrix schenckii, a fungus pathogenic for man and the Ceratocystis genus].

Sporothrix schenckii is a pathogenic fungus for man and animal. Its perfect form is not yet known. Many studies have been made to compare this fungus to ascomycetes belonging to the genus Ceratocystis. This paper summarizes some important data about the ecology and the epidemiology of the fungal complex Sporothrix-Ceratocystis. Previous results obtained by several groups of workers are strongly in favor of a relationship between the two genera. The epidemiological studies carried out in different areas have shown that Sporothrix schenckii and Ceratocystis stenoceras are frequently isolated from the same fragments of plants such as pine or eucalyptus. According to the time and areas, it appears that there is or there is not a relation between the presence of the fungus on the plants or in the soil and the disease. The former case is well illustrated by the epidemic of the Transvaal between 1940 and 1944. Sporothrix schenckii has been found to be present either in endemic areas like Guatemala (around the Ayarza Lake) or in Alsace, or in Corse where no case has been reported for a long time. In France, except for the curious epidemic observed between the years 1903 and 1912, no or very rare cases have been observed although Sporothrix schenckii is abundant in the soil and injuries with contaminated materials are probably extremely frequent. The presence or even the abundance of the fungus in nature is not enough to explain the development of the disease. Some not well known factors are necessary. So as for all disease, the immunological reaction of the host is important and the defects of these mechanisms must be suspected.

Ascomycota↗
PubMed1979

Tabanomyces milkoi (Dudka and Koval) emended, genus novum, a fungal pathogen of horseflies.

A fungus originally described as a new species of Coelomomyces (C. milkoi) from larval Tabanidae in the Ukraine, USSR, is transferred to a new genus, Tabanomyces, and described in detail. The zygospores germinate to form a linear four-celled conidiophore, each cell producing a spherical conidium ejected as in Conidiobolus, thus confirming that the organism belongs in the Entomophthorales. The resemblance between the conidiophore of Tabanomyces milkoi and the basidium of the rusts supports the old concept that the rust fungi may be related to the Entomophthorales.

Journal Article↗
PubMed1996

[Comparative genetics of representatives of the genus Yersinia and evolution of their pathogenicity].

This paper was prepared on the basis of a report presented at the first Congress of the All-Russian Society of Geneticists and Breeders (December 1994, Saratov, Russia). Analysis of published data and the authors' own investigations enabled them to propose a concept of evolution of pathogenicity within the Yersinia genus. They concluded that phenotypic features conferred by yersinia plasmids should be considered taxonomic traits.

Biological Evolution↗
PubMed1982

The relation of basic biology to pathogenic potential in the genus Chlamydia.

Chlamydiae are obligately intracellular procaryotic parasites, and their activities as agents of human disease are determined to a large degree by their intracellular way of life. The inside of a host cell is a hostile environment, and few microorganisms survive and multiply intracellularly. Those that do have evolved adaptations that fit them for life inside other cells. Apart from the viruses, chlamydiae are the infectious agents most highly adapted to intracellular life. Of all the properties of chlamydiae, the ones most likely to determine their pathogenic potential are those that reflect their adaptations to life inside host cells. Wherever possible, these chlamydial activities will be indentified and described.

Adaptation, Physiological↗
PubMed1995

[Immunochemical study on mannan, the antigenic polysaccharide of pathogenic yeasts in man of genus Candida].

This article accounts for the development of immunochemical studies on the antigenic polysaccharide, mannan, a major antigen of pathogenic yeast in man, genus Candida, in order to determine the chemical structures dominating the serological specificities of the parent cells as follows. 1. The serological classification system of 7 medically important Candida species by detecting 10 antigenic factors, 1, 4, 5, 6, 8, 9, 11, 13, 13b, and 34 the corresponding antisera, established by Tsuchiya and his coworkers is documented. 2. The structural studies of Candida mannans until early 1980s, which did not include any evidence for the presence of beta-1,2-linked Man unit, the common constituent of antigenic factors, 5, and 6, are also reviewed. 3. The process of structural identification of antigenic factor 5 residing in the mannans of C. albicans, C. tropicalis, and C. stellatoidea, in the phosphate-bound form of beta-1,2 linked mannooligosaccharides, is summarized. 4. The results of structural identification of antigenic factors 4 and 6 in the mannans of the acid-stable domains of C. albicans are summarized as follows: In order to isolate oligosaccharides containing beta-1,2 and alpha-1,6 linkages, a modified acetolysis method under mild conditions was established. By means of this procedure, oligosaccharides corresponding to antigenic factors 4 and 6 were successfully isolated, and their structures determined, subsequently. 5. Furthermore, effects of the alteration of cultivation conditions, carbon source, pH and temperature, on the chemical structure of mannans, especially of decrease and/or loss of densities of antigenic factors, 4, 5 and 6, are documented, because of the significance of these findings as basic concepts for in situ assay of Candida cells by antibody-staining technique in patients' foci.

Antigens, Fungal↗
PubMed1997

Antigenic relationships among pathogenic Beauveria bassiana with Engyodontium album (= B. alba) and non-pathogenic species of the genus Beauveria.

Exoantigenic extracts of 15 isolates belonging to hyalohyphomycosis-causing Beauveria bassiana (1), and Engyodontium album (1), as well as other species of the genus Beauveria (one isolate each of B. brogniartii, B. densa, B. stephanoderis, B. velata, B. vermiconia and six isolates of unknown Beauveria species) were studied. Aqueous-merthiolated extracts derived from 10-day-old Sabouraud's dextrose agar slant cultures (25 degrees C) were concentrated (25X), and reacted against rabbit anti-B. bassiana serum in the presence of partially purified homologous antigen (20X) prepared from 5-week-old shaken cultures (30 degrees C), using a microimmunodiffusion procedure. Beauveria bassiana reference antigen and antiserum reacted to produce four bands of identity. With the exception of E. album, which was negative, extracts of the isolates of B. brogniartii, B. densa, B. stephanoderis, B. velata, B. vermiconia and the unknown Beauveria species all produced 2-4 lines of identity against the homologous anti-B. bassiana serum. These results suggested that all the species of the genus Beauveria tested were antigenically related to B. bassiana. Engyodontium album demonstrated antigenic distinctness, however, from B. bassiana and thus supported the validity of this taxon.

Animals↗
PubMed1995

High constitutive levels of heat-shock proteins in human-pathogenic parasites of the genus Leishmania.

We have analysed the transcription of three heat-shock genes, HSP70, HSP83 and ClpB, in the protozoan parasite Leishmania. All three heat-shock genes are transcribed constitutively and not heat-inducibly. However, we find that two major heat-shock proteins, HSP70 and HSP83, are synthesized at elevated rates during heat stress. We conclude that the cellular stress response in Leishmaniae is regulated exclusively on a post-transcriptional level much in contrast with all other eukaryotes examined so far. The induced synthesis of HSP70 and HSP83, however, does not increase the steady-state level of either protein significantly. This is compensated by high constitutive levels of both proteins: HSP70 and HSP83 make up 2.1% and 2.8%, respectively, of the total protein in unstressed Leishmania promastigotes. Also, HSP70 is a strictly cytoplasmic protein in Leishmania and does not relocate into the nucleus during heat stress, as it does in other eukaryotes examined in the past.

Animals↗
PubMed1980

Radiomyces a genus in the Mucorales pathogenic for mice.

The thermotolerant fungi Radiomyces spectabilis and R. embreei were tested for their ability to produce disease when injected intravenously into mice. All three strains of R. embreei tested were able to produce death in normal and cortisone-treated mice. Hyphal invasion was consistently observed in the kidneys of these animals, and involvement of the brain, heart and lungs was often seen at inoculum dosages of 10(4) and 10(5) spores. The single strain of R. spectabilis tested did not produce deaths; although cortisone-treated animals sometimes exhibited unilateral kidney involvement at necropsy.

Animals↗
PubMed1979

Pathogenic species of the genus Haemophilus and Streptococcus pneumoniae produce immunoglobulin A1 protease.

Thirty-seven strains of the genus Haemophilus and five strains of Streptococcus pneumoniae were examined for their ability to produce extracellular enzyme that cleaves immunoglobulin molecules. All strains of H. influenzae, H. aegyptius, and S. pneumoniae elaborated enzyme that selectively cleaved human immunoglobulin A1 (IgA1) myeloma proteins but was inactive against a variety of other proteins including human IgA2, IgG, and IgM, porcine and bovine secretory IgA, human and bovine serum albumins, and ovalbumin. Although susceptible, human secretory IgA remained largely undigested. Two strains of H. pleuropneumoniae isolated from fatally infected pigs cleaved porcine secretory IgA, but had no effect on human IgA proteins. None of 16 strains that belonged to nonpathogenic Haemophilus species produced IgA protease. Analyses of the cleavage products of human IgA1 and secretory IgA proteins by immunochemical methods, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and analytical ultracentrifugation revealed that Fab and Fc fragments were produced. Since the production of IgA1 protease by Neisseria meningitidis has been reported previously, our finding that H. influenzae and S. pneumoniae produce an IgA1 protease indicates that this is a property of all three major etiological agents of bacterial meningitis. This suggests that IgA1 protease production may be an important factor in the pathogenesis of this disease.

Haemophilus↗
PubMed2001

Discrimination between Candida albicans and other pathogenic species of the genus Candida by their differential sensitivities to toxins of a panel of killer yeasts.

The differential sensitivities to toxins produced by a short panel of four killer yeasts allowed discrimination between 91 strains of the yeast Candida albicans and 223 non-C. albicans Candida strains. One hundred percent of C. albicans isolates exhibited negative results to the toxin panel, while 100% of non-C. albicans cultures gave well-defined and reproducible positive results to at least one of the four killer toxins. Among C. albicans strains only 96 and 87% gave germ tube (GT)- and chlamydospore-positive results, respectively. In addition a few GT-false-positive strains were detected among non-C. albicans isolates. Susceptibility to the toxin panel is apparently expressed more consistently than either GT or chlamydospore production and may constitute a promising basis for a new simple and easy-to-use procedure for routine discrimination between the species C. albicans and other species of the genus Candida.

Candida↗
PubMed2003

[The Alkhurma virus (family Flaviviridae, genus Flavivirus): an emerging pathogen responsible for hemorrhage fever in the Middle East].

To date tick-borne flaviviruses causing hemorrhagic fevers in humans have been isolated in Siberia (Omsk hemorrhagic fever virus), India (Kyasanur Forest disease virus), and Saudi Arabia (Akhurma virus). Because of their potential use as biological weapons for bioterrorism, these 3 viruses require level 4 biosafety handling facilities and have been listed as hypervirulent pathogens by the Center for Disease Control and Prevention. Alkhurma virus was isolated in 1995 from patients with hemorrhagic fever in Saudi Arabia. Current evidence suggests that transmission to humans can occur either transcutaneously either by contamination of a skin wound with the blood of an infected vertebrate or bites of an infected tick or orally by drinking unpasteurized contaminated milk. To date a total of 24 symptomatic human cases have been recorded with a mortality rate at 25% (6/24). Pauci-symptomatic or asymptomatic cases are likely but epidemiologic data are currently unavailable. The complete coding sequence of the prototype strain of Alkhurma virus was determined and published in 2001 based on international research project involving investigators from France, Great Britain, and Saudi Arabia. Phylogenetic studies demonstrate that closest known relative of Alkhurma virus is Kyasanur Forest disease virus and that both viruses share a common ancestor. Genetic analysis of several human strains sequentially isolated over a 5-year period showed a very low diversity. This finding has important potential implications for diagnosis and vaccination.

Animals↗
PubMedDate not supplied

[Effect of synthetic surfactants on some biological properties of non-pathogenic species of the genus Corynebacterium].

The influence of cationic, anionic and non-ionic synthetic surfactants on some biological properties of different representatives of the following species Corynebacterium glutamicum, Corynebacterium ammoniagenes, Corynebacterium vitaeruminis, Corynebacterium variabile and strain Corynebacterium sp. (Brevibacterium stationis) UKM As-719 has been investigated. It has been shown that the action of surfactants is accompanied by the change of cell morphology and loss of ability for Gram-staining, as well as by significant changes of antigenic properties and antibiotic-sensitivity of selected strains of corynebacteria. Nevertheless, no relations were established between the class of surfactants and changes in biological properties of the investigated strains. There was also no correlation between Gram-staining ability after the action of surfactants and change of corynebacteria antigenisity, as well as their antibiotic sensitivity.

Anions↗