4,945 research outputs found
MALDI-TOF-MS-based species identification and typing approaches in medical mycology
No full textMALDI-TOF MS-based species identification has found its place in many clinical routine diagnostic laboratories over the past years. Several well-established commercial systems exist and these allow precise analyses not only among bacteria, but also among clinically important yeasts. This methodology shows higher precision than biochemical and microscopic methods at significantly reduced turnaround times. Furthermore, the differentiation of different filamentous fungi including most dermatophytes and zygomycetes has been established. The direct identification of yeasts from blood culture bottles will be possible in a routine fashion with new standardized procedures. In addition to species identification, the MALDI-TOF MS technology offers several further possibilities, like assays to detect or predict resistance phenotypes in fungi as well as subtyping approaches to detect clinically relevant subgroups. The differences between the commercial systems are discussed with respect to fungi and an overview of their performances provided. Factors influencing outcome of MALDI-TOF-based species identification are discussed
The British ‘Bluesman’ Paul Oliver and the Nature of Transatlantic Blues Scholarship
No full textRecent revisionist studies have argued that much of what is known about music known as the blues’ has been 'invented' by the writing of enthusiasts far removed from the African American culture that created the music. Elijah Wald and Marybeth Hamilton in particular have attempted to sift through the clouds of romanticism, and tried to unveil more empirical histories that were previously obscured by the fallacious genre distinctions conjured up during the 1960s blues revival. While this revisionist scholarship has shed light on some previously ignored historical facts, writers have tended to concentrate on the romanticism of blues writing strictly from an American perspective, failing to acknowledge the genesis and influence of transatlantic scholarship, and therefore ignoring the work of the most prolific and influential blues scholar of the twentieth century, British writer Paul Oliver. By examining the core of Oliver’s research and writing during the 1950s and 1960s, this study aims to place Oliver in his rightful place at the centre of blues historiography. His scholarship allows a more detailed appreciation of the manner in which the blues was studied, through lyrics, recordings, oral histories, photography and African American literature. These historical sources were interpreted in accordance with the author’s attitudes to the commercial popular music, which allowed the ‘reconstruction’ of an African American ‘folk’ culture in which the blues became the antithesis of pop. Importantly, this study seeks to transcend dominant discourses of national cultural ownership or ethnocentrism, and demonstrate that representations of African American music and culture were constructed within a transatlantic context. The blues is music with roots in the African American experience within the United States; however, as Paul Oliver’s writing shows, its reception and representation were not limited by the same national, cultural or racial boundaries
Phylogenetic Distribution of csp1 Types in Aspergillus fumigatus and Their Correlates to Azole Antifungal Drug Resistance
No full textAspergillus fumigatus is a ubiquitously distributed saprophytic mold and a leading cause of invasive aspergillosis in human hosts. Pandemic azole-resistant strains have emerged on a global scale, which are thought to be propagated through use of azole-based fungicides in agriculture.ABSTRACT In Aspergillus fumigatus , the repetitive region of the csp1 gene is one of the most frequently used loci for intraspecies typing of this human pathogenic mold. Using PCR amplification and Sanger sequencing of only a single marker, csp1 typing is readily available to most laboratories and highly reproducible. Here, I evaluate the usefulness of the csp1 marker for resistance detection and epidemiologic stratification among A. fumigatus isolates. After resolving nomenclature conflicts from published studies and adding novel csp1 types, the number of known types now adds up to 38. Their distribution mostly correlates with A. fumigatus population structure, and they are also meaningful for narrowly defined cases of azole resistance phenotypes. Isolates carrying the pandemic resistance allele TR 34 /L98H show signs of interclade crossing of strains with t02 or t04A, into the t11 clade. Furthermore, absolute differences in voriconazole MIC values between t02/t04B versus t11 TR 34 /L98H isolates indicate that the genetic background of resistance mutations may have a pivotal role in cross-resistance phenotypes and, thus, clinical outcome and environmental selection. Despite the general genetic similarity of isolates with identical csp1 types, outcrossing into other clades is also observed. The csp1 type alone, therefore, does not sufficiently discriminate genetic clades to be used as the sole marker in epidemiologic studies. IMPORTANCE Aspergillus fumigatus is a ubiquitously distributed saprophytic mold and a leading cause of invasive aspergillosis in human hosts. Pandemic azole-resistant strains have emerged on a global scale, which are thought to be propagated through use of azole-based fungicides in agriculture. To perform epidemiologic studies, genetic typing of large cohorts is key. Here, I evaluate the usefulness of the frequently used csp1 marker for resistance detection and epidemiologic stratification among A. fumigatus isolates. The phylogenetic distribution of csp1 types mostly correlates with A. fumigatus population structure and is also meaningful for narrowly defined cases of azole resistance phenotypes. Nevertheless, outcrossing of csp1 into other clades is also observed. The csp1 type alone, therefore, does not sufficiently discriminate genetic clades and should not be used as the sole marker in epidemiologic studies.Aspergillus fumigatus is a ubiquitously distributed saprophytic mold and a leading cause of invasive aspergillosis in human hosts. Pandemic azole-resistant strains have emerged on a global scale, which are thought to be propagated through use of azole-based fungicides in agriculture.ABSTRACT In Aspergillus fumigatus , the repetitive region of the csp1 gene is one of the most frequently used loci for intraspecies typing of this human pathogenic mold. Using PCR amplification and Sanger sequencing of only a single marker, csp1 typing is readily available to most laboratories and highly reproducible. Here, I evaluate the usefulness of the csp1 marker for resistance detection and epidemiologic stratification among A. fumigatus isolates. After resolving nomenclature conflicts from published studies and adding novel csp1 types, the number of known types now adds up to 38. Their distribution mostly correlates with A. fumigatus population structure, and they are also meaningful for narrowly defined cases of azole resistance phenotypes. Isolates carrying the pandemic resistance allele TR 34 /L98H show signs of interclade crossing of strains with t02 or t04A, into the t11 clade. Furthermore, absolute differences in voriconazole MIC values between t02/t04B versus t11 TR 34 /L98H isolates indicate that the genetic background of resistance mutations may have a pivotal role in cross-resistance phenotypes and, thus, clinical outcome and environmental selection. Despite the general genetic similarity of isolates with identical csp1 types, outcrossing into other clades is also observed. The csp1 type alone, therefore, does not sufficiently discriminate genetic clades to be used as the sole marker in epidemiologic studies. IMPORTANCE Aspergillus fumigatus is a ubiquitously distributed saprophytic mold and a leading cause of invasive aspergillosis in human hosts. Pandemic azole-resistant strains have emerged on a global scale, which are thought to be propagated through use of azole-based fungicides in agriculture. To perform epidemiologic studies, genetic typing of large cohorts is key. Here, I evaluate the usefulness of the frequently used csp1 marker for resistance detection and epidemiologic stratification among A. fumigatus isolates. The phylogenetic distribution of csp1 types mostly correlates with A. fumigatus population structure and is also meaningful for narrowly defined cases of azole resistance phenotypes. Nevertheless, outcrossing of csp1 into other clades is also observed. The csp1 type alone, therefore, does not sufficiently discriminate genetic clades and should not be used as the sole marker in epidemiologic studies
Processing of predicted substrates of fungal Kex2 proteinases from <it>Candida albicans</it>, <it>C. glabrata</it>, <it>Saccharomyces cerevisiae </it>and <it>Pichia pastoris</it>
No full textAbstract Background Kexin-like proteinases are a subfamily of the subtilisin-like serine proteinases with multiple regulatory functions in eukaryotes. In the yeast Saccharomyces cerevisiae the Kex2 protein is biochemically well investigated, however, with the exception of a few well known proteins such as the α-pheromone precursors, killer toxin precursors and aspartic proteinase propeptides, very few substrates are known. Fungal kex2 deletion mutants display pleiotropic phenotypes that are thought to result from the failure to proteolytically activate such substrates. Results In this study we have aimed at providing an improved assembly of Kex2 target proteins to explain the phenotypes observed in fungal kex2 deletion mutants by in vitro digestion of recombinant substrates from Candida albicans and C. glabrata. We identified CaEce1, CA0365, one member of the Pry protein family and CaOps4-homolog proteins as novel Kex2 substrates. Conclusion Statistical analysis of the cleavage sites revealed extended subsite recognition of negatively charged residues in the P1', P2' and P4' positions, which is also reflected in construction of the respective binding pockets in the ScKex2 enzyme. Additionally, we provide evidence for the existence of structural constrains in potential substrates prohibiting proteolysis. Furthermore, by using purified Kex2 proteinases from S. cerevisiae, P. pastoris, C. albicans and C. glabrata, we show that while the substrate specificity is generally conserved between organisms, the proteinases are still distinct from each other and are likely to have additional unique substrate recognition.</p
A Reading By Poet Mary Oliver
No full textMary Oliver\u27s poetry, with her lyrical connection to the natural world, has firmly established her in the highest realm of American poets. She is renowned for her evocative and precise imagery, which brings nature into clear focus, transforming the everyday world into a place of magic and discovery. As poet Stanley Kunitz has said, Mary Oliver\u27s poetry is fine and deep; it reads like a blessing. Her special gift is to connect us with our sources in the natural world, its beauties and terrors and mysteries and consolations. Please join Pulitzer Prize-winning poet Mary Oliver as she shares her joyous, accessible, and intimate observations of the natural world.
Mary Oliver is the celebrated author of more than a dozen books of poetry and prose. With her lyrical connection to the natural world, Oliver\u27s poetry has firmly established her in the highest realm of American poets. Oliver has been honored with the National Book Award for Poetry, the Pulitzer Prize for Poetry, and a Guggenheim Foundation Fellowship, among others
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