32 research outputs found
Characterization of SCC\u3cem\u3emec \u3c/em\u3e Instability in Methicillin-Resistant \u3cem\u3eStaphylococcus aureus \u3c/em\u3e Affecting Adjacent Chromosomal Regions, Including the Gene for Staphylococcal Protein A \u3cem\u3e(spa)\u3c/em\u3e
Staphylococcal cassette chromosome mec (SCCmec) represents a sequence of clear clinical and diagnostic importance in staphylococci. At a minimum the chromosomal cassette contains the mecA gene encoding PBP2a but frequently also includes additional antibiotic resistance genes (e.g., ermA and aadC; macrolide and aminoglycoside resistance, respectively). Certain regions within SCCmec elements are hot spots for sequence instability due to cassette-specific recombinases and a variety of internal mobile elements. SCCmec changes may affect not only cassette stability but the integrity of adjacent chromosomal sequences (e.g., the staphylococcal protein A gene; spa). We investigated SCCmec stability in methicillin-resistant Staphylococcus aureus (MRSA) strains carrying one of four SCCmec types cultured in the absence of antimicrobial selection over a 3-month period. SCCmec rearrangements were first detected in cefoxitin-susceptible variants after 2 months of passage, and most commonly showed precise excision of the SCCmec element. Sequence analysis after 3 months revealed both precise SCCmec excision and a variety of SCCmec internal deletions, some including extensive adjacent chromosomal loss, including spa. No empty cassettes (i.e., loss of just mecA from SCCmec) were observed among the variants. SCCmec stability was influenced both by internal mobile elements (IS431) as well as the host cell environment. Genotypically similar clinical isolates with deletions in the spa gene were also included for purposes of comparison. The results indicate a role for host-cell influence and the IS431 element on SCCmec stability
CoordinateCleaner: Standardized cleaning of occurrence records from biological collection databases
© 2019 The Authors. Methods in Ecology and Evolution published by John Wiley & Sons Ltd on behalf of British Ecological Society. Species occurrence records from online databases are an indispensable resource in ecological, biogeographical and palaeontological research. However, issues with data quality, especially incorrect geo-referencing or dating, can diminish their usefulness. Manual cleaning is time-consuming, error prone, difficult to reproduce and limited to known geographical areas and taxonomic groups, making it impractical for datasets with thousands or millions of records. Here, we present CoordinateCleaner, an r-package to scan datasets of species occurrence records for geo-referencing and dating imprecisions and data entry errors in a standardized and reproducible way. CoordinateCleaner is tailored to problems common in biological and palaeontological databases and can handle datasets with millions of records. The software includes (a) functions to flag potentially problematic coordinate records based on geographical gazetteers, (b) a global database of 9,691 geo-referenced biodiversity institutions to identify records that are likely from horticulture or captivity, (c) novel algorithms to identify datasets with rasterized data, conversion errors and strong decimal rounding and (d) spatio-temporal tests for fossils. We describe the individual functions available in CoordinateCleaner and demonstrate them on more than 90 million occurrences of flowering plants from the Global Biodiversity Information Facility (GBIF) and 19,000 fossil occurrences from the Palaeobiology Database (PBDB). We find that in GBIF more than 3.4 million records (3.7%) are potentially problematic and that 179 of the tested contributing datasets (18.5%) might be biased by rasterized coordinates. In PBDB, 1205 records (6.3%) are potentially problematic. All cleaning functions and the biodiversity institution database are open-source and available within the CoordinateCleaner r-package
The curse of the uncultured fungus
The international DNA sequence databases abound in fungal sequences not annotated beyond the kingdom level, typically bearing names such as âuncultured fungusâ. These sequences beget low-resolution mycological results and invite further deposition of similarly poorly annotated entries. What do these sequences represent? This study uses a 767,918-sequence corpus of public full-length fungal ITS sequences to estimate what proportion of the 95,055 âuncultured fungusâ sequences that represent truly unidentifiable fungal taxa â and what proportion of them that would have been straightforward to annotate to some more meaningful taxonomic level at the time of sequence deposition. Our results suggest that more than 70% of these sequences would have been trivial to identify to at least the order/family level at the time of sequence deposition, hinting that factors other than poor availability of relevant reference sequences explain the low-resolution names. We speculate that researchersâ perceived lack of time and lack of insight into the ramifications of this problem are the main explanations for the low-resolution names. We were surprised to find that more than a fifth of these sequences seem to have been deposited by mycologists rather than researchers unfamiliar with the consequences of poorly annotated fungal sequences in molecular repositories. The proportion of these needlessly poorly annotated sequences does not decline over time, suggesting that this problem must not be left unchecked
Societal participation of individuals aged 55-64 years with and without chronic disease
Background: It is unknown whether an increase in societal participation is important for individuals with a chronic disease. This study explores whether having paid work, volunteer activities or informal care giving differs for individuals with a chronic disease and those without. Methods: Respondents (n = 1779) aged 55-64 years who participated in the Longitudinal Ageing Study Amsterdam in 2002/2003 or 2012/2013 were included. We tested differences in (combinations of) performing paid work, volunteer activities or informal care giving between participants with and without a chronic disease by regression analyses, while taking into account sociodemographic confounders and effect modification by year. Results: Having a chronic disease was associated with having paid work in 2002/2003 (OR: 0.5; 95% CI: 04-0.7), but not in 2012/2013 (OR: 0.7; 95% CI: 0.4-1.1). Work participation of participants with (OR: 1.5; 95% CI: 1.0-2.2) and without a chronic disease (OR: 2.3; 95% CI: 1.3-3.9) increased in 2012/2013. Participants with a chronic disease are more likely to participate in volunteer activities than paid work. No statistically significant associations were found between having a chronic disease and informal care giving. Conclusion: Participation in paid work differs between individuals aged 55-64 years with a chronic disease and those without, but participation in informal care giving did not. Individuals with a chronic disease are more likely to participate in volunteer activities than paid work. Future research should focus on differences in societal participation within heterogeneous group of individuals with a chronic disease, since differences may be present in subgroups with specific chronic diseases
Bispyrimidines as potent histamine H4 receptor ligands: delineation of structure activity relationships and detailed H4 receptor binding mode
The basic methylpiperazine moiety is considered a necessary substructure for high histamine