Disruption of FEM1C-W gene in zebra finch: evolutionary insights on avian ZW genes

Sex chromosome genes control sex determination and differentiation, but the mechanisms of sex determination in birds are unknown. In this study, we analyzed the gene FEM1C which is highly conserved from Caenorhabditis elegans to higher vertebrates and interacts with the sex determining pathway in C. elegans. We found that FEM1C is located on the Z and W chromosome of zebra finches and probably other Passerine birds, but shows only Z linkage in other avian orders. In the zebra finch, FEM1C-W is degraded because of a point mutation and possibly because of loss of the first exon containing the start methionine. Thus, FEM1C-W appears to have degenerated or been lost from most bird species. FEM1C-Z is expressed in a cytoplasmic location in zebra finch fibroblast cells, as in C. elegans. FEM1C represents an interesting example of evolutionary degradation of a W chromosome gene

The Student Experience of Two-Way Text-Message College Advising: A First Glimpse

This study examines the experiences of students enrolled in a text-messaging advising program in order to understand the conditions for impact in this rapidly proliferating intervention model. The program under study was a 15-state text-messaging college advising trial that attempted to increase the college enrollment outcomes of over 30,000 students who attended U.S. high schools with large percentages of low-income students. Data came from 3600 advisees who responded to text-message queries about their experiences in the texting program. The content of the queries was informed by focus group responses from 18 program participants. Results indicate that text-message college advising offered students a combination of information, assistance, nudges, and emotional support that many students perceived kept them on track for a successful college process. Text-message advisees who were disengaged or critical of the program mistakenly believed that the advising was fully automated, had sufficient support elsewhere, or were not receiving the texts because of incorrect contact information. Study findings suggest that text messaging is best suited to providing advising on financial aid and other topics requiring specific information and concrete tasks. Students’ reports of their experience in the program provide potential explanations for the mixed results that are beginning to be reported for texting programs and suggest implications for more effective designs. The study is useful as one of the first investigations of student responses to virtual advising, but its modest response rates suggest the need for new approaches to collecting evaluation data from participants in text-message advising campaigns

From Benchside to Community Research: Development of Affordable and Accessible Probiotic Foods in East Africa

Probiotics are live microorganisms that, when ingested in adequate amounts, confer health benefits. In 2004, Western Heads East brought Fiti to East Africa and trained women how to produce Fiti probiotic yogurt. Fiti is composed of a probiotic culture, Lactobacillus rhamnosus GR-1, and a starter strain, Streptococcus thermophilus C1062. This initiative has since empowered low-income groups to gain financial independence, particularly women. There are currently ~250 kitchens feeding over 250,000 consumers daily in East Africa. A challenge with accessing Fiti yoghurt is the fluctuating cost of milk and inconsistent supply of high quality milk. A potential solution is the consumption of Fiti through affordable non-dairy foods. Pilot studies reveal bacterial viability of Fiti probiotics in probiotic mango juice, orange juice, pineapple juice, mango juice, and millet porridge; there remains no sensory data on these products from East African populations. The research questions sought to examine how individuals in Tanzania and Kenya rated different non-dairy probiotic foods; how these ratings compared to probiotic yoghurt; and how these rating correlated with the willingness of individuals to consume non-dairy probiotic products

A Fully Nonmetallic Gas Turbine Engine Enabled by Additive Manufacturing, Part II: Additive Manufacturing and Characterization of Polymer Composites

This publication is the second part of the three part report of the project entitled "A Fully Nonmetallic Gas Turbine Engine Enabled by Additive Manufacturing" funded by NASA Aeronautics Research Institute (NARI). The objective of this project was to conduct additive manufacturing to produce aircraft engine components by Fused Deposition Modeling (FDM), using commercially available polyetherimides-Ultem 9085 and experimental Ultem 1000 mixed with 10% chopped carbon fiber. A property comparison between FDM-printed and injection molded coupons for Ultem 9085, Ultem 1000 resin and the fiber-filled composite Ultem 1000 was carried out. Furthermore, an acoustic liner was printed from Ultem 9085 simulating conventional honeycomb structured liners and tested in a wind tunnel. Composite compressor inlet guide vanes were also printed using fiber-filled Ultem 1000 filaments and tested in a cascade rig. The fiber-filled Ultem 1000 filaments and composite vanes were characterized by scanning electron microscope (SEM) and acid digestion to determine the porosity of FDM-printed articles which ranged from 25 to 31%. Coupons of Ultem 9085, experimental Ultem 1000 composites and XH6050 resin were tested at room temperature and 400F to evaluate their corresponding mechanical properties. A preliminary modeling was also initiated to predict the mechanical properties of FDM-printed Ultem 9085 coupons in relation to varied raster angles and void contents, using the GRC-developed MAC/GMC program

Dosage compensation is less effective in birds than in mammals

<p>Abstract</p> <p>Background</p> <p>In animals with heteromorphic sex chromosomes, dosage compensation of sex-chromosome genes is thought to be critical for species survival. Diverse molecular mechanisms have evolved to effectively balance the expressed dose of X-linked genes between XX and XY animals, and to balance expression of X and autosomal genes. Dosage compensation is not understood in birds, in which females (ZW) and males (ZZ) differ in the number of Z chromosomes.</p> <p>Results</p> <p>Using microarray analysis, we compared the male:female ratio of expression of sets of Z-linked and autosomal genes in two bird species, zebra finch and chicken, and in two mammalian species, mouse and human. Male:female ratios of expression were significantly higher for Z genes than for autosomal genes in several finch and chicken tissues. In contrast, in mouse and human the male:female ratio of expression of X-linked genes is quite similar to that of autosomal genes, indicating effective dosage compensation even in humans, in which a significant percentage of genes escape X-inactivation.</p> <p>Conclusion</p> <p>Birds represent an unprecedented case in which genes on one sex chromosome are expressed on average at constitutively higher levels in one sex compared with the other. Sex-chromosome dosage compensation is surprisingly ineffective in birds, suggesting that some genomes can do without effective sex-specific sex-chromosome dosage compensation mechanisms.</p

Processes influencing ozone levels in Alaskan forest fire plumes during long-range transport over the North Atlantic

A case of long-range transport of a biomass burning plume from Alaska to Europe is analyzed using a Lagrangian approach. This plume was sampled several times in the free troposphere over North America, the North Atlantic and Europe by three different aircraft during the IGAC Lagrangian 2K4 experiment which was part of the ICARTT/ITOP measurement intensive in summer 2004. Measurements in the plume showed enhanced values of CO, VOCs and NOy , mainly in form of PAN. Observed O3 levels increased by 17 ppbv over 5 days. A photochemical trajectory model, CiTTyCAT, was used to examine processes responsible for the chemical evolution of the plume. The model was initialized with upwind data and compared with downwind measurements. The influence of high aerosol loading on photolysis rates in the plume was investigated using in situ aerosol measurements in the plume and lidar retrievals of optical depth as input into a photolysis code (Fast-J), run in the model. Significant impacts on photochemistry are found with a decrease of 18% in O3 production and 24% in O3 destruction over 5 days when including aerosols. The plume is found to be chemically active with large O3 increases attributed primarily to PAN decomposition during descent of the plume toward Europe. The predicted O3 changes are very dependent on temperature changes during transport and also on water vapor levels in the lower troposphere which can lead to O3 destruction. Simulation of mixing/dilution was necessary to reproduce observed pollutant levels in the plume. Mixing was simulated using background concentrations from measurements in air masses in close proximity to the plume, and mixing timescales (averaging 6.25 days) were derived from CO changes. Observed and simulated O3/CO correlations in the plume were also compared in order to evaluate the photochemistry in the model. Observed slopes change from negative to positive over 5 days. This change, which can be attributed largely to photochemistry, is well reproduced by multiple model runs even if slope values are slightly underestimated suggesting a small underestimation in modeled photochemical O3 production. The possible impact of this biomass burning plume on O3 levels in the European boundary layer was also examined by running the model for a further 5 days and comparing with data collected at surface sites, such as Jungfraujoch, which showed small O3 increases and elevated CO levels. The model predicts significant changes in O3 over the entire 10 day period due to photochemistry but the signal is largely lost because of the effects of dilution. However, measurements in several other BB plumes over Europe show that O3 impact of Alaskan fires can be potentially significant over Europe

Expanded molecular diversity generation during directed evolution by trinucleotide exchange (TriNEx)

Trinucleotide exchange (TriNEx) is a method for generating novel molecular diversity during directed evolution by random substitution of one contiguous trinucleotide sequence for another. Single trinucleotide sequences were deleted at random positions in a target gene using the engineered transposon MuDel that were subsequently replaced with a randomized trinucleotide sequence donated by the DNA cassette termed SubSeqNNN. The bla gene encoding TEM-1 β-lactamase was used as a model to demonstrate the effectiveness of TriNEx. Sequence analysis revealed that the mutations were distributed throughout bla, with variants containing single, double and triple nucleotide changes. Many of the resulting amino acid substitutions had significant effects on the in vivo activity of TEM-1, including up to a 64-fold increased activity toward ceftazidime and up to an 8-fold increased resistance to the inhibitor clavulanate. Many of the observed amino acid substitutions were only accessible by exchanging at least two nucleotides per codon, including charge-switch (R164D) and aromatic substitution (W165Y) mutations. TriNEx can therefore generate a diverse range of protein variants with altered properties by combining the power of site-directed saturation mutagenesis with the capacity of whole-gene mutagenesis to randomly introduce mutations throughout a gene

Challenges for children and adolescents with cancer in Europe:The SIOP-Europe agenda

In Europe, 6,000 young people die of cancer yearly, the commonest disease causing death beyond the age of 1 year. In addition, 300,000-500,000 European citizens are survivors of a childhood cancer and up to 30% of them have severe long-term sequelae of their treatment. Increasing both cure and quality of cure are the two goals of the European paediatric haematology/oncology community. SIOPE coordinates and facilitates research, care and training which are implemented by the 18 European study groups and 23 national paediatric haematology/oncology societies. SIOPE is the European branch of the International Society of Paediatric Oncology and one of the six founding members of the European Cancer Organisation. SIOPE is preparing its strategic agenda to assure long-term sustainability of clinical and translational research in paediatric malignancies over the next 15 years. SIOPE tackles the issues of equal access to standard care and research across Europe and improvement of long term follow up. SIOPE defined a comprehensive syllabus for training European specialists. A strong partnership with parent, patient and survivor organisations is being developed to successfully achieve the goals of this patient-centred agenda. SIOPE is advocating in the field of EU policies, such as the Clinical Trials Regulation and the Paediatric Medicine Regulation, to warrant that the voice of young people is heard and their needs adequately addressed. SIOPE and the European community are entirely committed to the global agenda against childhood cancers to overcome the challenges to increasing both cure and quality of cure of young people with cancer

Molecular cloning and characterization of the germline-restricted chromosome sequence in the zebra finch

The zebra finch (Taeniopygia guttata) germline-restricted chromosome (GRC) is the largest chromosome and has a unique system of transmission in germ cells. In the male, the GRC exists as a single heterochromatic chromosome in the germline and is eliminated from nuclei in late spermatogenesis. In the female, the GRC is bivalent and euchromatic and experiences recombination. These characteristics suggest a female-specific or female-beneficial function of the GRC. To shed light on the function of GRC, we cloned a portion of the GRC using random amplified polymorphic DNA–polymerase chain reaction and analyzed it using molecular genetic and cytogenetic methods. The GRC clone hybridized strongly to testis but not blood DNA in genomic Southern blots. In fluorescent in situ hybridization analysis on meiotic chromosomes from synaptonemal complex spreads, the probe showed hybridization across a large area of the GRC, suggesting that it contains repetitive sequences. We isolated a sequence homologous to the GRC from zebra finch chromosome 3 and a region of chicken chromosome 1 that is homologous to zebra finch chromosome 3; the phylogenetic analysis of these three sequences suggested that the GRC sequence and the zebra finch chromosome 3 sequence are most closely related. Thus, the GRC sequences likely originated from autosomal DNA and have evolved after the galliform–passeriform split. The present study provides a foundation for further study of the intriguing GRC