Changes in DNA secondary structure afterγ-irradiation

Native calf thymus DNA was gamma-irradiated at 500 mug/ml in 0.01 M NaCl in the presence or absence of oxygen. By irradiation, an increasing amount of DNA becomes reactive with a water-soluble carbodiimide-derivative (CMEC). In the DNA sections reactive with CMEC the nucleotide strands are separated, a phenomenon previously described as radiation-induced denaturation. The dose-effect curve for the formation of denatured DNA shows an upward-bent form; a distinct oxygen effect of about 2 is observed. By a comparative study with DNA samples, degraded partially with DNAse I, it was shown that a minor part of the radiation-induced denaturation results from the formation of the radiation-induced single strand breaks, whereas the major part is a local denaturation independent of the strand breaks. In these locally denatured regions 20 to 50 nucleotide pairs are separated.     

Immunoreactive material resembling ovine prolactin in perikarya and nerve terminals of the rat hypothalamus

Summary The presence of prolactin (PRL)-like material is demonstrated in the brain of rats with the aid of anti-ovine PRL (oPRL) IgG as primary antibody in the unlabeled antibody-enzyme method. Immunoreactive deposits are visualized as an intraneuronal constituent with a widespread distribution in the hypothalamus and neural lobe of the pituitary. Dense networks of reactive nerve terminals derived from two prominent fibre tracts, a ventral (VHT) and a dorsal hypothalamo-neurohypophysial tract (DHT) are seen. The VHT is confined to the median eminence and pars oralis tuberis, the DHT to the pars caudalis tuberis. Both fibre tracts pass through the infundibular stalk into the neural lobe. The origin of the immunoreactive nerve terminals can be elucidated only to some extent. The VHT gives off beaded fibres entering the ependymal and glandular layer of the median eminence. Immunoreactive perikarya are observed in the supraoptic nucleus, the paraventricular nucleus, the anterior hypothalamic nucleus, the anterior commissural nucleus, the preoptic nucleus and the interstitial nucleus of the stria terminalis. A few of the immunoreactive perikarya are observed in close connection with brain vessels and the ependymal cells of the third ventricle. The results indicate that the anti-oPRL has a unique region specificity implying that only a segment of the mammalian PRL molecule is present in these nuclei of the brain. Fragments of PRL may function as neuromodulators or neurotransmitters in the rat brain.We are indebted to Dr. Mogens Hammer, Rigshospitalet, Copenhagen for the gift of Arg-VP and anti-VP, and to NIAMDD for the gift of ovine PRL, ratPRL, anti-rPRL, anti-hPRL and bovineSTH     

A genome‐wide linkage map for the house sparrow (Passer domesticus) provides insights into the evolutionary history of the avian genome

The house sparrow is an important model species for studying physiological, ecological and evolutionary processes in wild populations. Here, we present a medium density, genome wide linkage map for house sparrow (Passer domesticus) that has aided the assembly of the house sparrow reference genome, and that will provide an important resource for ongoing mapping of genes controlling important traits in the ecology and evolution of this species. Using a custom house sparrow 10 K iSelect Illumina SNP chip we have assigned 6,498 SNPs to 29 autosomal linkage groups, based on a mean of 430 informative meioses per SNP. The map was constructed by combining the information from linkage with that of the physical position of SNPs within scaffold sequences in an iterative process. Averaged between the sexes; the linkage map had a total length of 2,004 cM, with a longer map for females (2,240 cM) than males (1,801 cM). Additionally, recombination rates also varied along the chromosomes. Comparison of the linkage map to the reference genomes of zebra finch, collared flycatcher and chicken, showed a chromosome fusion of the two avian chromosomes 8 and 4A in house sparrow. Lastly, information from the linkage map was utilized to conduct analysis of linkage disequilibrium (LD) in eight populations with different effective population sizes (N_e) in order to quantify the background level LD. Together, these results aid the design of future association studies, facilitate the development of new genomic tools and support the body of research that describes the evolution of the avian genome.     

Development and Analysis of qPCR for the Identification of Arthroconidial Yeasts of the Genus Magnusiomyces

The arthroconidial yeasts Magnusiomyces capitatus and M. clavatus are emerging opportunistic pulmonary pathogens. They are closely related and difficult to distinguish based on morphological and physiological traits. We applied an SYBR^® green-based quantitative PCR (qPCR) assay to identify the species. We analyzed 30 reference strains originating from clinical and environmental sources by targeting the Rpb2 gene encoding the second largest subunit of RNA polymerase II. The qPCR assays were tested by direct identification of M. capitatus and M. clavatus in spiked sputum and household dishwasher swabs, respectively, as models for clinical and environmental samples. The assays were proved to be reliable for species-level identification of both species, with 100% sensitivity and 100% specificity, lowest inter-assay deviations (RSDr?≤?1.65%, R² values >0.99), detection limit of 10 theoretical copy number of target DNA, and detection cell limit of ≥5000 yeast cells from spiked sputum samples. The developed qPCR assay is a practical molecular approach for the detection of M. capitatus and M. clavatus that can be used as a stand-alone assay or in conjunction with culture-dependent approaches.

     

Monosialoganglioside Increases Catalase Activity in Cerebral Cortex of Rats

Monosialoganglioside (GM1) is a neuroprotective agent that has been reported to scavenge free radicals generated during reperfusion and to protect receptors and enzymes from oxidative damage. However, only a few studies have attempted to investigate the effects of GM1 on enzymatic antioxidant defenses of the brain. In the present study, we evaluate the effects of the systemic administration of GM1 on the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px), and on spontaneous chemiluminescence and total radical-trapping potential (TRAP) in cerebral cortex of rats ex vivo. The effects of GM1 on CAT activity and spontaneous chemiluminescence in vitro were also determined.

Animals received two injections of GM1 (50?mg/kg, i.p.) or saline (0.85% NaCl, i.p.) spaced 24?h apart. Thirty minutes after the second injection the animals were sacrificed and enzyme activities and spontaneous chemiluminescence and TRAP were measured in cell-free homogenates. GM1 administration reduced spontaneous chemiluminescence and increased catalase activity ex vivo, but had no effect on TRAP, SOD or GSH-Px activities. GM1, at high concentrations, reduced CAT activity in vitro. We suggest that the antioxidant activity of GM1 ganglioside in the cerebral cortex may be due to an increased catalase activity.     

Synthesis of (2′,5′)-Oligoadenylate Antisense Chimeras Targeting Steroid 5α-Reductase

Abstract

2–5A antisense chimeras have been synthesized which target human steroid 5α-reductase mRNA. To enhance the stability of the chimera towards degradative enzymes the terminal phosphodiester bond was isomerized from 3′,5′ to 3′,3′ and the 5′-phosphate group was thiolated.     

How Enrichment Affects Exploration Trade-Offs in Rats: Implications for Welfare and Well-Being

We propose that a comparative approach to well-being could be the key to understanding ‘the good life.’ Inspired by current theories of human well-being and animal welfare, we designed a novel test of exploration behavior. Environmentally and socially enriched Long-Evans female rats (N = 60) were trained in four simultaneously presented arms of an eight-arm radial-maze. They learned to expect successes in two arms and failures in the other two. After training, 20 animals remained in enriched housing (enrichment-maintenance) while 40 animals were re-housed in standard, isolated conditions (enrichment-removal). Two weeks later, all animals were re-tested in the maze, initially with access to the four familiar arms only. In the final minute, they also had access to the unfamiliar ambiguous-arms. Though both groups showed significant interest in the ambiguous-arms (P<.0001), the enrichment-maintenance group showed a significantly greater exploratory tendency (P<.01) despite having equivalent levels of activity (P>.3). Thus, we show not only that rats will abandon known rewards and incur risk in order to explore, indicating that exploration is valuable in its own right, but also that individuals with (vs. without) enriched housing conditions are more likely to engage in such exploratory behavior. This novel test contributes to the body of knowledge examining the importance of exploration in humans and other animals; implications for animal welfare and human well-being are discussed.