The comparison of susceptibility patterns of Gram-negative invasive and non-invasive pathogens in Estonian hospitals

A total of 560 invasive and 1062 non-invasive isolates were collected. The antimicrobial susceptibility of invasive versus non-invasive Pseudomonas aeruginosa, Acinetobacter baumannii, and Klebsiella pneumoniae isolates were evaluated using the E-tests. The equal domination of Gram-negative among both invasive and non-invasive pathogens was estimated in our study if contaminants were excluded. The emergence trend of Gram-positive microbes especially of coagulase negative staphylococci may be proved only after application of exclusive algorithms. Due to similar susceptibility, the data of non-invasive Gram-negative pathogens can be useful to predict resistance of invasive ones. Also, the surveillance of invasive pathogens provides useful information about the general susceptibility of pathogens.     

Euchromatic and heterochromatic domains at Drosophila telomeres.

Noncoding repetitive sequences make up a large portion of eukaryotic genomes, but their function is not well understood. Large blocks of repetitive DNA-forming heterochromatin around the centromeres are required for this region to function properly, but are difficult to analyze. The smaller regions of heterochromatin at the telomeres provide an opportunity to study their DNA and protein composition. Drosophila telomere length is maintained through the targeted transposition of specific non-long terminal repeat retrotransposons to chromosome ends, where they form long tandem arrays. A subterminal telomere-associated sequence (TAS) lies immediately proximal to the terminal-retrotransposon array. Here, we review the experimental support for the heterochromatic features of Drosophila telomeres, and provide evidence that telomeric regions contain 2 distinct chromatin subdomains: TAS, which exhibits features that resemble beta heterochromatin; and the terminal array of retrotransposons, which appears euchromatic. This organization is significantly different from the telomeric organization of other eukaryotes, where the terminal telomerase-generated repeats are often folded in a t-loop structure and become part of the heterochromatin protein complex.     

Insights to Genetic Characterization Tools for Epidemiological Tracking of Francisella tularensis in Sweden

Tularaemia, caused by the bacterium Francisella tularensis, is endemic in Sweden and is poorly understood. The aim of this study was to evaluate the effectiveness of three different genetic typing systems to link a genetic type to the source and place of tularemia infection in Sweden. Canonical single nucleotide polymorphisms (canSNPs), MLVA including five variable number of tandem repeat loci and PmeI-PFGE were tested on 127 F. tularensis positive specimens collected from Swedish case-patients. All three typing methods identified two major genetic groups with near-perfect agreement. Higher genetic resolution was obtained with canSNP and MLVA compared to PFGE; F. tularensis samples were first assigned into ten phylogroups based on canSNPs followed by 33 unique MLVA types. Phylogroups were geographically analysed to reveal complex phylogeographic patterns in Sweden. The extensive phylogenetic diversity found within individual counties posed a challenge to linking specific genetic types with specific geographic locations. Despite this, a single phylogroup (B.22), defined by a SNP marker specific to a lone Swedish sequenced strain, did link genetic type with a likely geographic place. This result suggests that SNP markers, highly specific to a particular reference genome, may be found most frequently among samples recovered from the same location where the reference genome originated. This insight compels us to consider whole-genome sequencing (WGS) as the appropriate tool for effectively linking specific genetic type to geography. Comparing the WGS of an unknown sample to WGS databases of archived Swedish strains maximizes the likelihood of revealing those rare geographically informative SNPs.     

Immunochemical studies on two DT diaphorase active antigens isolated from rat liver cytosol by affinity chromatography

Two immunologically different DT diaphorases were isolated on an affinity column containing Dicumarol as ligand from the cytosol fraction of rat liver. With a specific antiserum raised in rabbits against the DT diaphorase fraction eluted from the column, the two DT diaphorases were shown with immunodiffusion methods to be present in the microsomal and mitochondrial as well as in the cytosol fraction of rat liver. The NAD(P)H oxidizing activity in the immunoprecipitates containing the two DT diaphorases was found to be inhibited by 10^?4m Dicumarol but not by 10^?3m 2-pivaloyl-1,3-indandione or warfarin. With the anti-DT diaphorase antiserum the two DT diaphorases were also demonstrated to be present in other organs but with a somewhat different distribution. One of them appeared predominantly in kidney and heart and the other in lung, brain, testis, and spleen. The latter DT diaphorase was also found to be retained in four 3-methylcholanthrene-induced rat hepatomas. These findings indicate different physiological functions for the two DT diaphorases which at present are unknown.     

A non-filamentous configuration of intermediate-sized filament proteins inDrosophila Kc tissue culture cells

Summary Using monoclonal antibodies against the major intermediate filament (10 nm) cytoskeletal proteins ofDrosophila tissue culture cells, we showed by indirect immunofluorescence and ammuno-electron microscopy that this cytoskeletal material also occurs in a non-filamentous configuration. Patches of fine granular material are detected in the cytoplasm of Kc cells but are absent in anotherDrosophila cell line (Schneider, line 2). These patches are surrounded by membranes with bound ribosomes, resembling endoplasmic reticulum, and are found throughout the cytoplasm. We suggest that these aggregates are caused by overproduction of intermediate filament material in the Kc cell line. This work was supported by a Fogarty International Fellowship from the NIH to M.F.W., and by a Heinsenberg Fellowship from the Deutsche Forschungsgemeinschaft, Bonn, to. H.B.