2,797 research outputs found
A study of candidate genes for day blindness in the standard wire haired dachshund
<p>Abstract</p> <p>Background</p> <p>A genetic study was performed to identify candidate genes associated with day blindness in the standard wire haired dachshund. Based on a literature review of diseases in dogs and human with phenotypes similar to day blindness, ten genes were selected and evaluated as potential candidate genes associated with day blindness in the breed.</p> <p>Results</p> <p>Three of the genes, <it>CNGB3</it>, <it>CNGA3 </it>and <it>GNAT2</it>, involved in cone degeneration and seven genes and loci, <it>ABCA4</it>, <it>RDH5</it>, <it>CORD8</it>, <it>CORD9</it>, <it>RPGRIP1</it>, <it>GUCY2D </it>and <it>CRX</it>, reported to be involved in cone-rod dystrophies were studied. Polymorphic markers at each of the candidate loci were studied in a family with 36 informative offspring. The study revealed a high frequency of recombinations between the candidate marker alleles and the disease.</p> <p>Conclusion</p> <p>Since all of the markers were at the exact position of the candidate loci, and several recombinations were detected for each of the loci, all ten genes were excluded as causal for this canine, early onset cone-rod dystrophy. The described markers may, however, be useful to screen other canine resource families segregating eye diseases for association to the ten genes.</p
Hydrotreatment of Fast Pyrolysis Bio-oil Fractions Over Nickel-Based Catalyst
Residual biomass shows potential to be used as a feedstock for fast pyrolysis bio-oil production for energetic and chemical use. Although environmentally advantageous, further catalytic upgrading is required in order to increase the bio-oil stability, by reducing reactive compounds, functional oxygen-containing groups and water content. However, bio-oils may separate in fractions either spontaneously after ageing or by fractionated condensation. Therefore the effects of upgrading on different fast pyrolysis bio-oil (FPBO) fractions obtained from a commercially available FPBO were studied by elemental analysis, GC-MS and 1H-NMR. Not only the FPBO was upgraded by catalytic hydrotreatment, but also the heavy phase fraction formed after intentional aging and phase separation. The reactions were conducted between 175 and 325 °C and 80–100 bar by using a nickel–chromium catalyst in batch experiments. The influence of the hydrotreatment conditions correlated with the composition of the upgraded products. Higher oxygen removal was obtained at higher temperatures, whereas higher pressures resulted in higher hydrogen consumption with no significant influence on deoxygenation. At 325 °C and 80 bar 42% of the oxygen content was removed from the FPBO. Compounds attributed to pyrolysis oil instability, such as ketones and furfural were completely converted while the number of alcohols detected in the upgraded products increased. Coke formation was observed after all reactions, especially for the reaction with the fraction rich in lignin derivatives, likely formed by polymerization of phenolic compounds mainly concentrated in this phase. Independently of the feedstock used, the upgraded bio-oils were very similar in composition, with reduced oxygen and water content, higher energy density and higher carbon content
An Obesity Risk SNP (rs17782313) near the MC4R Gene Is Associated with Cerebrocortical Insulin Resistance in Humans
Activation of melanocortin-4 receptor (MC4R) by insulin sensitive neurons is a central mechanism in body weight regulation, and genetic variants in the MC4R gene (e.g., rs17782313) are associated with obesity. By using magnetoencephalography, we addressed whether rs17782313 affects the cerebrocortical insulin response. We measured the cerebrocortical insulin response by using magnetoencephalography in a hyperinsulinemic euglycemic clamp (versus placebo) in 51 nondiabetic humans (26 f/25 m, age 35 ± 3 years, BMI 28 ± 1 kg/m2). The C-allele of rs17782313 was minor allele (frequency 23%), and the genotype distribution (TT 30, TC 19, CC 2) was in Hardy-Weinberg-Equilibrium. Insulin-stimulated cerebrocortical theta activity was decreased in the presence of the C-allele (TT 33 ± 16 fT; TC/CC −27 ± 20 fT; P = .023), and this effect remained significant after adjusting for BMI and peripheral insulin sensitivity (P = .047). Cerebrocortical theta activity was impaired in carriers of the obesity risk allele. Therefore, cerebral insulin resistance may contribute to the obesity effect of rs17782313
Functional characterization of Arabidopsis ARGONAUTE 3 in reproductive tissues
Arabidopsis encodes ten ARGONAUTE (AGO) effectors of RNA silencing, canonically loaded with either 21‐22 nucleotide (nt) long small RNAs (sRNA) to mediate post‐transcriptional‐gene‐silencing (PTGS) or 24nt sRNAs to promote RNA‐directed‐DNA‐methylation. Using full‐locus constructs, we characterized the expression, biochemical properties, and possible modes of action of AGO3. Although AGO3 arose from a recent duplication at the AGO2 locus, their expression patterns differ drastically, with AGO2 being expressed in both male and female gametes whereas AGO3 accumulates in aerial vascular terminations and specifically in chalazal seed integuments. Accordingly, AGO3 down‐regulation alters gene expression in siliques. Similar to AGO2, AGO3 binds sRNAs with a strong 5’‐adenosine bias, but unlike Arabidopsis AGO2, it binds most efficiently 24nt sRNAs. AGO3 immunoprecipitation experiments in siliques revealed that these sRNAs mostly correspond to genes and intergenic regions in a manner reflecting their respective accumulation from their loci‐of‐origin. AGO3 localizes to the cytoplasm and co‐fractionates with polysomes to possibly mediate PTGS via translation inhibition
"Silent revolution?" The changing access to higher education for non-traditional students in Germany
Die Öffnung der Hochschulen in Deutschland für nicht-traditionelle Studierende hat in jüngster Zeit zunehmend an Aufmerksamkeit gewonnen. Welche bildungs- und arbeitsmarktpolitischen Debatten, hochschulrechtlichen Entwicklungen und Maßnahmen damit verbunden sind und inwieweit sich Letztere auch in der tatsächlichen Beteiligung nichttraditioneller Studierender an Hochschulbildung widerspiegeln, soll in diesem Beitrag näher betrachtet werden. (DIPF/Orig.)The opening of higher education institutions for non-traditional students in Germany has increasingly gained attention in recent years. This paper presents the debates on education and labour market policy, regulations on access to higher education as well as measures connected with this process and deals with the question to what extent the latter are reflected in the actual participation of non-traditional students. (DIPF/Orig.
Monitoring fish communities through environmental DNA metabarcoding in the fish pass system of the second largest hydropower plant in the world
The Itaipu Hydroelectric Power Plant is the second largest in the world in power generation. The artificial barrier created by its dam imposes an obstacle for fish migration. Thus, in 2002, a fish pass system, named Piracema Channel, was built to allow fish to access areas upstream of the reservoir. We tested the potential of environmental DNA metabarcoding to monitor the impact of both the dam and associated fish pass system in the Paraná River fish communities and to compare it with traditional monitoring methods. Using a fragment of the 12S gene, we characterized richness and community composition based on amplicon sequence variants, operational taxonomic units, and zero-radius OTUs. We combined GenBank and in-house data for taxonomic assignment. We found that different bioinformatics approaches showed similar results. Also, we found a decrease in fish diversity from 2019 to 2020 probably due to the recent extreme drought experienced in southeastern Brazil. The highest alpha diversity was recorded in the mouth of the fish pass system, located in a protected valley with the highest environmental heterogeneity. Despite the clear indication that the reference databases need to be continuously improved, our results demonstrate the analytical efficiency of the metabarcoding to monitor fish species
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