Anaerobic degradation of papermill sludge in a two-phase digester containing rumen microorganisms and colonized polyurethane foam

Summary The use of reticulated polyurethane foam as a support material for the immobilization of methanogenic associations and its application to the anaerobic treatment of fine particulate solid wastes was investigated. The colonization of polyurethane support particles in a continuous upflow reactor fed on a mixture of acetate, propionate and butyrate, was both rapid and dense. The combination of rumen microorganisms and colonized support particles in a two-phase digester resulted in an efficient anaerobic decomposition of papermill sludge.     

Prion protein gene analysis in three kindreds with fatal familial insomnia (FFI): codon 178 mutation and codon 129 polymorphism.

Fatal familial insomnia (FFI) is a disease linked to a GAC(Asp)-->AAC(Asn) mutation in codon 178 of the prion protein (PrP) gene. FFI is characterized clinically by untreatable progressive insomnia, dysautonomia, and motor dysfunctions and is characterized pathologically by selective thalamic atrophy. We confirmed the 178Asn mutation in the PrP gene of a third FFI family of French ancestry. Three family members who are under 40 years of age and who inherited the mutation showed only reduced perfusion in the basal ganglia on single photon emission computerized tomography. Some FFI features differ from the clinical and neuropathologic findings associated with 178Asn reported elsewhere. However, additional intragenic mutations accounting for the phenotypic differences were not observed in two affected individuals. In other sporadic and familial forms of Creutzfeldt-Jakob disease and Gerstmann-Sträussler syndrome, Met or Val homozygosity at polymorphic codon 129 is associated with a more severe phenotype, younger age at onset, and faster progression. In FFI, young and old individuals at disease onset had 129Met/Val. Moreover, of five 178Asn individuals who are above age-at-onset range and who are well, two have 129Met and three have 129Met/Val, suggesting that polymorphic site 129 does not modulate FFI phenotypic expression. Genetic heterogeneity and environment may play an important role in inter- and intrafamilial variability of the 178Asn mutation.     

Immunity to Heligmosomoides polygyrus induced by subcutaneous vaccination with post-infection larvae

The objective of this study was to investigate, using the Heligmosomoides polygyrus (= Nematospiroides dubius)-mouse model, whether live post-infection trichostrongylid larvae recovered from the intestinal wall of donor animals and placed subcutaneously would serve as vaccine protecting against oral challenge by third-stage (infective) larvae (L3). Experiments were conducted to determine the effect of number and age of post-infective larvae as well as age and sex of host on vaccination. Vaccinated BALB/cByJ mice were challenged with 30 L3 and total adult worm burdens compared between vaccinated groups and sham-treated controls (greater than 90% infection rates). All mice subcutaneously vaccinated with either five or 10 larvae harbored significantly fewer challenge parasites in their intestines than did sham-treated controls (P less than 0.001). Both young and mature mice were significantly protected against challenge by the subcutaneous larval vaccine. Adult female mice had significantly (P less than 0.05) fewer parasites than adult male mice. The age of the larvae (indicated as the days between infection and harvesting of the larvae) was important in that day-4 or day-6 larvae (L4) were significantly more protective (P less than 0.001) than day-2 (L3) or day-8 larvae (L5-preadult). Reduction in worm burden for young vaccinated animals ranged from 31 to 39% (P less than 0.001) and for mature animals from 88 to 100% (P less than 0.001). Passive transfer to serum resulted in the reduction of worm burdens by 26-40% (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of genomic information on optimal contribution selection in livestock breeding programs

Background

Long-term benefits in animal breeding programs require that increases in genetic merit be balanced with the need to maintain diversity (lost due to inbreeding). This can be achieved by using optimal contribution selection. The availability of high-density DNA marker information enables the incorporation of genomic data into optimal contribution selection but this raises the question about how this information affects the balance between genetic merit and diversity.

Methods

The effect of using genomic information in optimal contribution selection was examined based on simulated and real data on dairy bulls. We compared the genetic merit of selected animals at various levels of co-ancestry restrictions when using estimated breeding values based on parent average, genomic or progeny test information. Furthermore, we estimated the proportion of variation in estimated breeding values that is due to within-family differences.

Results

Optimal selection on genomic estimated breeding values increased genetic gain. Genetic merit was further increased using genomic rather than pedigree-based measures of co-ancestry under an inbreeding restriction policy. Using genomic instead of pedigree relationships to restrict inbreeding had a significant effect only when the population consisted of many large full-sib families; with a half-sib family structure, no difference was observed. In real data from dairy bulls, optimal contribution selection based on genomic estimated breeding values allowed for additional improvements in genetic merit at low to moderate inbreeding levels. Genomic estimated breeding values were more accurate and showed more within-family variation than parent average breeding values; for genomic estimated breeding values, 30 to 40% of the variation was due to within-family differences. Finally, there was no difference between constraining inbreeding via pedigree or genomic relationships in the real data.

Conclusions

The use of genomic estimated breeding values increased genetic gain in optimal contribution selection. Genomic estimated breeding values were more accurate and showed more within-family variation, which led to higher genetic gains for the same restriction on inbreeding. Using genomic relationships to restrict inbreeding provided no additional gain, except in the case of very large full-sib families.     

Increased oxidative damage to all DNA bases in patients with type II diabetes mellitus

Gas chromatography-mass spectrometry was used to measure the oxidative DNA damage in diabetic subjects and controls. Levels of multiple DNA base oxidation products, but not DNA base de-amination or chlorination products, were found to be elevated in white blood cell DNA from patients with type II diabetes as compared with age-matched controls. The chemical pattern of base damage is characteristic of that caused by an attack on DNA by hydroxyl radical. An increased formation of the highly reactive hydroxyl radical could account for many of the reports of oxidative stress in diabetic subjects. There was no evidence of an increased DNA damage by reactive nitrogen or chlorine species.     

A novel dynein light intermediate chain colocalizes with the retrograde motor for intraflagellar transport at sites of axoneme assembly in chlamydomonas and Mammalian cells

The assembly of cilia and flagella depends on bidirectional intraflagellar transport (IFT). Anterograde IFT is driven by kinesin II, whereas retrograde IFT requires cytoplasmic dynein 1b (cDHC1b). Little is known about how cDHC1b interacts with its cargoes or how it is regulated. Recent work identified a novel dynein light intermediate chain (D2LIC) that colocalized with the mammalian cDHC1b homolog DHC2 in the centrosomal region of cultured cells. To see whether the LIC might play a role in IFT, we characterized the gene encoding the Chlamydomonas homolog of D2LIC and found its expression is up-regulated in response to deflagellation. We show that the LIC subunit copurifies with cDHC1b during flagellar isolation, dynein extraction, sucrose density centrifugation, and immunoprecipitation. Immunocytochemistry reveals that the LIC colocalizes with cDHC1b in the basal body region and along the length of flagella in wild-type cells. Localization of the complex is altered in a collection of retrograde IFT and length control mutants, which suggests that the affected gene products directly or indirectly regulate cDHC1b activity. The mammalian DHC2 and D2LIC also colocalize in the apical cytoplasm and axonemes of ciliated epithelia in the lung, brain, and efferent duct. These studies, together with the identification of an LIC mutation, xbx-1(ok279), which disrupts retrograde IFT in Caenorhabditis elegans, indicate that the novel LIC is a component of the cDHC1b/DHC2 retrograde IFT motor in a variety of organisms.     

Validity of Epidemiological Data in Risk Assessment Applications

Data from epidemiological studies might be seen as superior to data from animal bioassays for risk assessment purposes. Because humans are the population of interest, use of epidemiological data avoids interspecies extrapolation. However, one must not assume that an epidemiological study is necessarily valid at face value. We describe issues of validity that arise in the conduct and interpretation of epidemiological research and that affect the utility of epidemiological data in risk assessment. These issues include choice of study design, size and representativeness of the study sample, measurement of exposures and outcomes, control of confounding and specification of statistical model for analysis of data, all of which affect the accuracy and validity of study results.     

Thrombin causes the Enrichment of Rat Brain Primary Cultures with Ependymal Cells Via Protease-Activated Receptor 1

Ependymal cell culture models from rat have been developed over the last 20 years to facilitate biochemical studies on this least-studied glial cell type. The cell culture protocol calls for the presence of thrombin, which is essential for obtaining a high proportion of multiciliated ependymal cells. The serine protease appears to act via protease-activated receptor 1 to prevent the apoptosis of ependymal precursors and enhance their proliferation without affecting contaminating cells. Unciliated precursors differentiate into polyciliated ependymocytes by passing through a stage of monociliation. The message for protease-activated receptor (PAR) 1 is initially abundant in the cultures, but its level declines as the cells differentiate. Besides PAR 1, signalling through PAR 2 also promotes ciliation in rat brain primary cultures, albeit to a lesser degree than the thrombin receptor. Thrombin and other proteases may be involved in the regulation of ventricular wall development. This action would be mediated mainly by PAR1.     

A novel mode of chromosomal evolution peculiar to filamentous Ascomycete fungi

Background  

Gene loss, inversions, translocations, and other chromosomal rearrangements vary among species, resulting in different rates of structural genome evolution. Major chromosomal rearrangements are rare in most eukaryotes, giving large regions with the same genes in the same order and orientation across species. These regions of macrosynteny have been very useful for locating homologous genes in different species and to guide the assembly of genome sequences. Previous analyses in the fungi have indicated that macrosynteny is rare; instead, comparisons across species show no synteny or only microsyntenic regions encompassing usually five or fewer genes. To test the hypothesis that chromosomal evolution is different in the fungi compared to other eukaryotes, synteny was compared between species of the major fungal taxa.