A comparison between a PCR method and a conventional culture method for detecting pathogenic Yersinia enterocolitica in food

The beige mutation is a murine autosomal recessive disorder, resulting in hypopigmentation, bleeding and immune cell dysfunction. The gene defective in beige is thought to be a homologue of the gene for the human disorder Chediak-Higashi syndrome. We have identified the murine beige gene by in vitro complementation and positional cloning, and confirmed its identification by defining mutations in two independent mutant alleles. The sequence of the beige gene message shows strong nucleotide homology to multiple human ESTs, one or more of which may be associated with the Chediak-Higashi syndrome gene. The amino acid sequence of the Beige protein revealed a novel protein with significant amino acid homology to orphan proteins identified in Saccharomyces cerevisiae, Caenorhabditis elegans and humans.     

Estimation of genetic parameters and heterosis for longevity in crossbred Danish dairy cattle

Crossbreeding has been shown to improve the longevity of dairy cattle in countries across the world. The aim of this study was to estimate heterosis, breed effects, and genetic parameters for longevity in crossbred dairy cattle among Danish Holstein (DH), Danish Red (DR), and Danish Jersey (DJ) breeds. Data were provided from 119 Danish commercial herds that use systematic crossbreeding (i.e., rotational crossbreeding). Additional data from 11 mixed-breed herds with DH and DJ were included to estimate reliable breed effects for DJ. Survival information on 73,741 cows was analyzed with a linear animal model using the artificial insemination–REML algorithm in the DMU package. Five longevity (L) traits were defined: days from first calving until the end of first lactation or culling (L1), days from first calving until the end of second lactation or culling (L2), days from first calving until the end of third lactation or culling (L3), days from first calving until the end of fourth lactation or culling (L4), and days from first calving until the end of fifth lactation or culling (L5). Heritabilities ranged between 0.022 and 0.090. Additive breed effects in units of days were estimated relative to DH for DR as ?0.5 (L1), +10.5 (L2), +18.5 (L3), +11.9 (L4), and +28.6 (L5), and corresponding figures for DJ were +2.0, +0.5, +14.2, +27.7, and +44.0. Heterosis effects in L1 were low (1.2%) but favorable in crosses between DH and DR, whereas negative heterosis effects were estimated for crosses between DH and DJ (?2.5%) and DR and DJ (?1.2%). The largest heterosis effects for L2, L3, L4, and L5 were found in DH × DR and were favorable (+3.3, +5.7, +7.7, and +8.5%, respectively). Corresponding figures for heterosis effects in DH × DJ and DR × DJ were favorable as well: +2.3, +4.1, +5.6, and +6.2% in DH × DJ and +3.1, +7.3, +6.9, and +7.2% in DR × DJ. The favorable heterosis effects show that crossbreeding is an efficient tool for improving longevity in Danish dairy cattle.     

Electrical conductivity of milk: ability to predict mastitis status

Electrical conductivity (EC) of milk has been introduced as an indicator trait for mastitis over the last decade, and it may be considered as a potential trait in a breeding program where selection for improved udder health is included. In this study, various EC traits were investigated for their association with udder health. In total, 322 cows with 549 lactations were included in the study. Cows were classified as healthy or clinically or subclinically infected, and EC was measured repeatedly during milking on each quarter. Four EC traits were defined; the inter-quarter ratio (IQR) between the highest and lowest quarter EC values, the maximum EC level for a cow, IQR between the highest and lowest quarter EC variation, and the maximum EC variation for a cow. Values for the traits were calculated for every milking throughout the entire lactation. All EC traits increased significantly (P < 0.001) when cows were subclinically or clinically infected. A simple threshold test and discriminant function analysis was used to validate the ability of the EC traits to distinguish between cows in different health groups. Traits reflecting the level rather than variation of EC, and in particular the IQR, performed best to classify cows correctly. By using this trait, 80.6% of clinical and 45.0% of subclinical cases were classified correctly. Of the cows classified as healthy, 74.8% were classified correctly. However, some extra information about udder health status was obtained when a combination of EC traits was used.     

Miniaturized and automated sample pretreatment for determination of PCBs in environmental aqueous samples using an on-line microporous membrane liquid-liquid extraction-gas chromatography system

A new, fast, and automated sample pretreatment technique for determination of lipophilic organic compounds in aqueous samples has been developed and applied to the determination of polychlorinated biphenyls (PCBs) in environmental river water. It is based on miniaturized microporous membrane liquid-liquid extraction coupled on-line to gas chromatography (GC) with electron capture detection. The heart of the system that simultaneously connects the sample pretreatment step to the final GC analysis has been named the extracting syringe (ESy). The ESy carries a miniaturized membrane extraction card attached to an electrically and mechanically designed installment and is mounted directly over a GC injector for fully automated injection of the extract. A method was developed to extract 10 PCB congeners from 1-mL water samples (after addition of 40% acetonitrile) with an extraction time of 10 min. The optimized methodology showed good linearity (in the dynamic concentration range of 5 ng L(-)(1)-1 microg L(-)(1)), enrichment factors of 33-40 times, repeatable extractions (RSD 2-5%, n = 4), and low detection limits (2-3 ng L(-)(1)). Acetonitrile had to be added to the samples in order to overcome the influence of PCB adsorption on the repeatability of extraction and enrichment and to minimize the overall memory effect (OME). OME and carryover depended not only on the concentration of the organic solvent added to the sample and that used in the washing procedure but also on whether the extracting card was changed or not. When an optimized washing procedure was applied, the OME was approximately 0.2% at high concentrations (i.e., 1 microg L(-)(1)). When each extraction took place in a new extraction card, no OME was detected. Additionally, no significant adsorption onto glass surfaces or a matrix effect on extraction was noticed. The main features of this methodology are good extraction repeatability, low detection limits at short extraction time, and the unsurpassed characteristic of no detectable OME in the entire system when each sample is processed in a new card. The total consumption of organic (nonchlorinated) solvents is less than 5 mL per sample.     

A perspective on the history of the Charles Babbage Institute andthe Charles Babbage Foundation

Erwin Tomash developed an interest in the history of computing and information processing early in the 1960s. Capping a successful business career many years later, and after a number of exploratory consultations with historians, business colleagues, archives, and museum professionals, he pursued his historical interest by founding the Charles Babbage Institute     

Photo-click immobilization on quartz crystal microbalance sensors for selective carbohydrate-protein interaction analyses

A photoclick method based on azide photoligation and Cu-catalyzed azide-alkyne cycloaddition has been evaluated for the immobilization of carbohydrates to polymeric materials. The biomolecular recognition properties of the materials have been investigated with regard to applicable polymeric substrates and selectivity of protein binding. The method was used to functionalize a range of polymeric surfaces (polystyrene, polyacrylamide, poly(ethylene glycol), poly(2-ethyl-2-oxazoline), and polypropene) with various carbohydrate structures (based on α-D-mannose, β-D-galactose, and N-acetyl-β-D-glucosamine). The functionalized surfaces were evaluated in real-time studies of protein-carbohydrate interactions using a quartz crystal microbalance flow-through system with a series of different carbohydrate-binding proteins (lectins). The method proved to be robust and versatile, resulting in a range of efficient sensors showing high and predictable protein selectivities.     

Analysis of noncovalent chitinase-chito-oligosaccharide complexes by infrared-matrix assisted laser desorption ionization and nanoelectrospray ionization mass spectrometry

Transferring noncovalently bound complexes from the condensed phase into the gas phase represents a challenging task due to weak intermolecular bonds that have to be maintained during the phase transition. Currently, electrospray ionization (ESI) is the standard mass spectrometric (MS) technique to analyze noncovalent complexes. Although infrared matrix-assisted laser desorption ionization (IR-MALDI)-MS also provides particular soft desorption/ionization conditions, this method has so far hardly been applied for the analysis of noncovalent complexes. In this study, we employed IR-MALDI orthogonal time-of-flight (o-TOF)-MS in combination with the liquid matrix glycerol to characterize the specific complex formation of chito-oligosaccharide (CHOS) ligands with two variants of Chitinase A (ChiA) from Serratia marcescens, the inactive E315Q mutant and the active W167A mutant, respectively. The IR-MALDI-o-TOF-MS results were compared to those obtained using nano-ESI-quadrupole (q)-TOF-MS and ultraviolet (UV)-MALDI-o-TOF-MS. Using IR-MALDI-o-TOF-MS, specific noncovalent complexes between ChiA and CHOS were detected with distributions between enzymes with bound oligosaccharides vs free enzymes that were essentially identical to those obtained by nano-ESI-q-TOF-MS. Chitinase-CHOS complexes were not detected when UV-MALDI was employed for desorption/ionization. The results show that IR-MALDI-MS can be a valuable tool for fast and simple screening of noncovalent enzyme-ligand interactions.     

Differentiating myoepithelial and acinar cells in rat neonatal parotid gland and histogenetic concepts for salivary gland tumors

Histogenetic concepts for salivary gland tumors are predicated on the presence of reserve or undifferentiated cells in normal glands, presumably the source for cell renewal and induction of tumors. Developing rat parotid gland, which remains fetal-like at birth, provides the opportunity to study differentiation and observe whether cytologically undifferentiated cells do or do not have functional indicators of specific differentiation pathways. Immunohistochemistry and immuno-electron microscopy, when applied to parotid gland at birth, at 12 days of age and in the adult gland, indicate that commitment to myoepithelial cell differentiation occurs prior to development of structural changes characteristic of these cells. Conversely, secretory granules are evident in differentiating acinar cells prior to synthesis of amylase. The results suggest that an appearance of undifferentiation does not confer reserve cell status either in the normal salivary gland or their tumors.