Giardia duodenalis and Giardia enterica in children: first evidence of assemblages A and B in Eastern Slovakia.

For an overview on the occurrence of Giardia assemblages in children in Eastern Slovakia, we examined 259 faecal samples of children from the segregated settlement in Medzev, 30 samples of children from the orphanage in Medzev and 40 samples of children with autism from the Special Elementary School in Kosice. Thirty-eight samples (14.67 %) from the segregated settlement, 19 samples (63.33 %) from the orphanage and two samples (5.0 %) from the Special Elementary School were positive for Giardia by flotation. The initial microscopic diagnostics were completed by the genotyping of the triosephosphate isomerase-gene loci (tpi genes) which revealed the existence of two Giardia assemblages in Slovak population, namely Giardia duodenalis (assemblage A) and Giardia enterica (assemblage B). These results represent the first evidence of A and B assemblages in children in Slovakia. Epidemiological significance and the impact on the public health of Giardia infection are highlighted.

Resonance-assisted stabilisation of hydrogen bonds probed by NMR spectroscopy and path integral molecular dynamics.

Path integral molecular dynamics and experimental NMR data are used to investigate resonance-assisted hydrogen bonds (RAHBs). When nuclear delocalisation is included in chemical shift calculations, the agreement with experiment is excellent, while static calculations show very poor performance. The results support the concept of RAHB, which has recently been questioned.

Separation of planar rotamers through intramolecular hydrogen bonding in polysubstituted 5-nitrosopyrimidines.

While purifying new polysubstituted 5-nitrosopyrimidines, the unique separation of pairs of rotamers as chemical species, stabilized by a single intramolecular hydrogen bond and differing only in nitroso group orientation, was achieved. This interesting stereochemical phenomenon is compared to the well-known atropisomerism.

PCR identification of Salmonella cells in food and stool samples after immunomagnetic separation.

The purpose of the present study was to investigate the application of various sample preparation methods (cell washing before lysis, purification of DNA using phenol extraction method, immunomagnetic separation-IMS) for the final PCR identification of Salmonella cells. The presence of PCR inhibitors in processed food products (milk powder and dried eggs) can be the cause of false-negative results in PCR without IMS of target cells. It was also demonstrated that IMS-PCR was successfully used for identification and quick confirmation of untypical Salmonella strains isolated from human stool samples and rabbit meat. However, IMS cannot eliminate intracellular PCR inhibitors present in immunoseparated Salmonella cells. These inhibitors must be taken into consideration in evaluation of PCR procedure.