Development of a multiplex real-time PCR assay for the detection of ruminant DNA

The U.S. Food and Drug Administration (FDA) has previously validated a real-time PCR-based assay that is currently being used by the FDA and several state laboratories as the official screening method. Due to several shortcomings to the assay, a multiplex real-time PCR assay (MRTA) to detect three ruminant species (bovine, caprine, and ovine) was developed using a lyophilized bead design. The assay contained two primer or probe sets: a "ruminant" set to detect bovine-, caprine-, and ovine-derived materials and a second set to serve as an internal PCR control, formatted using a lyophilized bead design. Performance of the assay was evaluated against stringent acceptance criteria developed by the FDA's Center for Veterinary Medicine's Office of Research. The MRTA for the detection of ruminant DNA passed the stringent acceptance criteria for specificity, sensitivity, and selectivity. The assay met sensitivity and reproducibility requirements by detecting 30 of 30 complete feed samples fortified with meals at 0.1 % (wt/wt) rendered material from each of the three ruminant species. The MRTA demonstrated 100 % selectivity (0.0 % false positives) for negative controls throughout the assessment period. The assay showed ruggedness in both sample selection and reagent preparation. Second and third analyst trials confirmed the quality of the written standard operating procedure with consistency of results. An external laboratory participating in a peer-verification trial demonstrated 100 % specificity in identifying bovine meat and bone meal, while exhibiting a 0.03 % rate of false positives. The assay demonstrated equal levels of sensitivity and reproducibility compared with the FDA's current validated real-time PCR assay. The assay detected three prohibited species in less than 1.5 h of total assay time, a significant improvement over the current real-time assay. These results demonstrated this assay's suitability for routine regulatory use both as a primary screening tool and as a confirmatory test.     

Stability of arsenic compounds in seafood samples during processing and storage by freezing

In this study, the stability of arsenic compounds in fresh and frozen samples of raw, boiled and fried Atlantic cod (Gadhus morhua), Atlantic salmon (Salmo salar) and blue mussel (Mytilus edulis) were examined. Results show that the total arsenic concentrations of the fresh Atlantic cod and Atlantic salmon samples were not different from the frozen samples within the same seafood type. For blue mussel, the total arsenic concentration decreased significantly after storage. Inorganic arsenic was found only in blue mussels and, importantly, no significant increase of inorganic arsenic was observed after processing or after storage by freezing. The content of tetramethylarsonium ion was generally low in all samples types, but increased significantly in all fried samples of both fresh and frozen seafood. Upon storage by freezing, the arsenobetaine content was reduced significantly, but only in the samples of blue mussels.     

全球电子废物的研究(下)

(续接本刊2007年第11期第42页) 　　3中国、印度和南非的电子废物管理及评述 　　3.1发展中国家和转型期国家面临的特殊问题 　　上面已经提到了部分发展中国家和转型期国家面临的特殊问题,总结如下: 　　①尽管国内人均电子废物的产生量仍相对较小,但对于人口大国而言,如中国和印度,电子废物的绝对产生量大(Empa,2005). 　　……     

Sharing morphemes without sharing meaning: Production and comprehension of German verbs in the context of morphological relatives.

We investigated the impact of derived German verbs on the production and recognition of morphologically related simple verbs. In order to disentangle effects of morphological, semantic, and phonological relatedness, target verbs were combined (e.g., z?hlen – to count) with four context verbs: Two morphologically related context verbs that were either semantically transparent (verz?hlen – to miscount) or semantically opaque (erz?hlen – to tell), a semantically related (rechnen – to calculate) and a phonologically related (z?hmen – to tame) context verb. Morphologically related complex verbs reduced picture naming latencies as well as lexical decision latencies. Semantically related verbs did not show any reliable effects. In production, morphological facilitation was almost four times larger than phonological facilitation. In comprehension, pure form overlap produced inhibition. We argue that in German, production and comprehension processes operate on morphologically decomposed lexical form representations. Independent from semantic transparency, complex verbs are broken down into their morphemes during comprehension and are assembled during production. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Blood Cell Responses Following Heavy Alcohol Consumption Coincide with Changes in Acute Phase Reactants of Inflammation,Indices of Hemolysis and Immune Responses to Ethanol Metabolites

Aberrations in blood cells are common among heavy alcohol drinkers. In order to shed further light on such responses, we compared blood cell status with markers of hemolysis, mediators of inflammation and immune responses to ethanol metabolites in alcohol-dependent patients at the time of admission for detoxification and after abstinence. Blood cell counts, indices of hemolysis (LDH, haptoglobin, bilirubin), calprotectin (a marker of neutrophil activation), suPAR, CD163, pro- and anti-inflammatory cytokines and autoantibodies against protein adducts with acetaldehyde, the first metabolite of ethanol, were measured from alcohol-dependent patients (73 men, 26 women, mean age 43.8 ± 10.4 years) at baseline and after 8 ± 1 days of abstinence. The assessments also included information on the quantities of alcohol drinking and assays for biomarkers of alcohol consumption (CDT), liver function (AST, ALT, ALP, GGT) and acute phase reactants of inflammation. At baseline, the patients showed elevated values of CDT and biomarkers of liver status, which decreased significantly during abstinence. A significant decrease also occurred in LDH, bilirubin, CD163 and IgA and IgM antibodies against acetaldehyde adducts, whereas a significant increase was noted in blood leukocytes, platelets, MCV and suPAR levels. The changes in blood leukocytes correlated with those in serum calprotectin (p < 0.001), haptoglobin (p < 0.001), IL-6 (p < 0.02) and suPAR (p < 0.02). The changes in MCV correlated with those in LDH (p < 0.02), MCH (p < 0.01), bilirubin (p < 0.001) and anti-adduct IgG (p < 0.01). The data indicates that ethanol-induced changes in blood leukocytes are related with acute phase reactants of inflammation and release of neutrophil calprotectin. The studies also highlight the role of hemolysis and immune responses to ethanol metabolites underlying erythrocyte abnormalities in alcohol abusers.     

Oxidized banana starch–polyvinyl alcohol film: Partial characterization

Composites of polyvinyl alcohol, native banana starch, oxidized banana starch using glycerol like plasticizer, were studied by mechanical tests (MT), scanning electronic microscopy (SEM), differential scanning calorimetry (DSC) and solubility in water. The oxidized banana starch showed higher level of carboxyl groups than of carbonyl groups. Composites of native banana starch/polyvinyl alcohol and oxidized banana starch/polyvinyl alcohol showed irregularities, indicating incomplete dispersion of the polymers. However, the film elaborated with the blend oxidized banana starch/polyvinyl alcohol showed the highest mechanical properties and the melting temperature of the first transition, as well as the lowest water vapor permeability, indicating higher interaction between both polymers. The composite oxidized banana starch/polyvinyl alcohol showed higher water solubility than the one of its counterpart with native banana starch at 25°C, and similar values were obtained for both films at 60°C. The oxidation of banana starch in order to elaborate a film blended with polyvinyl alcohol improved some mechanical and barrier properties, and this composite could be used for specific applications in the packing of food.