Stable transformation of an episomal protein-tagging shuttle vector in the piscine diplomonad Spironucleus vortens

<p>Abstract</p> <p>Background</p> <p>Diplomonads are common free-living inhabitants of anoxic aquatic environments and are also found as intestinal commensals or parasites of a wide variety of animals. <it>Spironucleus vortens </it>is a putatively commensal diplomonad of angelfish that grows to high cell densities in axenic culture. Genomic sequencing of <it>S. vortens </it>is in progress, yet little information is available regarding molecular and cellular aspects of <it>S. vortens </it>biology beyond descriptive ultrastructural studies. To facilitate the development of <it>S. vortens </it>as an additional diplomonad experimental model, we have constructed and stably transformed an episomal plasmid containing an enhanced green fluorescent protein (GFP) tag, an AU1 epitope tag, and a tandem affinity purification (TAP) tag. This construct also contains selectable antibiotic resistance markers for both <it>S. vortens </it>and <it>E. coli</it>.</p> <p>Results</p> <p>Stable transformants of <it>S. vortens </it>grew relatively rapidly (within 7 days) after electroporation and were maintained under puromycin selection for over 6 months. We expressed the enhanced GFP variant, eGFP, under transcriptional control of the <it>S. vortens </it>histone H3 promoter, and visually confirmed diffuse GFP expression in over 50% of transformants. Next, we generated a histone H3::GFP fusion using the <it>S. vortens </it>conventional histone H3 gene and its native promoter. This construct was also highly expressed in the majority of <it>S. vortens </it>transformants, in which the H3::GFP fusion localized to the chromatin in both nuclei. Finally, we used fluorescence <it>in situ </it>hybridization (FISH) of the episomal plasmid to show that the transformed plasmid localized to only one nucleus/cell and was present at roughly 10–20 copies per nucleus. Because <it>S. vortens </it>grows to high densities in laboratory culture, it is a feasible diplomonad from which to purify native protein complexes. Thus, we also included a TAP tag in the plasmid constructs to permit future tagging and subsequent purification of protein complexes by affinity chromatography via a two-step purification procedure.</p> <p>Conclusion</p> <p>Currently, progress in protistan functional and comparative genomics is hampered by the lack of free-living or commensal protists in axenic culture, as well as a lack of molecular genetic tools with which to study protein function in these organisms. This stable transformation protocol combined with the forthcoming genome sequence allows <it>Spironucleus vortens </it>to serve as a new experimental model for cell biological studies and for comparatively assessing protein functions in related diplomonads such as the human intestinal parasite, <it>Giardia intestinalis</it>.</p

Comparison of dot chromosome sequences from D. melanogaster and D. virilis reveals an enrichment of DNA transposon sequences in heterochromatic domains

BACKGROUND: Chromosome four of Drosophila melanogaster, known as the dot chromosome, is largely heterochromatic, as shown by immunofluorescent staining with antibodies to heterochromatin protein 1 (HP1) and histone H3K9me. In contrast, the absence of HP1 and H3K9me from the dot chromosome in D. virilis suggests that this region is euchromatic. D. virilis diverged from D. melanogaster 40 to 60 million years ago. RESULTS: Here we describe finished sequencing and analysis of 11 fosmids hybridizing to the dot chromosome of D. virilis (372,650 base-pairs) and seven fosmids from major euchromatic chromosome arms (273,110 base-pairs). Most genes from the dot chromosome of D. melanogaster remain on the dot chromosome in D. virilis, but many inversions have occurred. The dot chromosomes of both species are similar to the major chromosome arms in gene density and coding density, but the dot chromosome genes of both species have larger introns. The D. virilis dot chromosome fosmids have a high repeat density (22.8%), similar to homologous regions of D. melanogaster (26.5%). There are, however, major differences in the representation of repetitive elements. Remnants of DNA transposons make up only 6.3% of the D. virilis dot chromosome fosmids, but 18.4% of the homologous regions from D. melanogaster; DINE-1 and 1360 elements are particularly enriched in D. melanogaster. Euchromatic domains on the major chromosomes in both species have very few DNA transposons (less than 0.4 %). CONCLUSION: Combining these results with recent findings about RNAi, we suggest that specific repetitive elements, as well as density, play a role in determining higher-order chromatin packaging

Design and Methods for an Intervention Utilizing Peer Facilitators to Reduce Adolescent Obesity: Team Up for Healthy Living

The proportion of obese adolescents in Southern Appalachia is among the highest in the nation. Currently there are few effective programs that address this issue, especially among high school students. Through funding from the National Institute on Minority Health and Health Disparities in the National Institutes of Health, the Team Up for Healthy Living Project targets obesity prevention in adolescents through a crosspeer intervention. The specific aims of the project are: 1) To develop a peer-based health education program focusing on establishing positive peer norms and supportive peer relationships toward healthy eating and physical activity among high school students, 2) To test the efficacy of the program, and 3) To explore the mechanisms underlying the program. The intervention is based on the Theory of Planned Behavior, which presupposes that human behavior is primarily driven by attitude, subjective norms, perceived behavior control, and social support. Through influencing these components, the intervention is expected to improve eating behavior, increase physical activity, and lead to healthier body weight among adolescents in Southern Appalachia. Ten area high schools were selected to be a part of the project, and schools were matched based on similar demographics (school size and number of students enrolled) and were randomized to intervention or control. Wave one of baseline data collection was completed in January 2012; with 265 students assigned to intervention and 276 to control. A second wave of subject recruitment will occur in fall 2012. To deliver the intervention, undergraduate students from the disciplines of Public Health, Nutrition, and Kinesiology were trained as peer facilitators. These peer facilitators are teaching the eight-week Team Up curriculum during Lifetime Wellness classes at intervention schools. The curriculum focuses on nutrition awareness, physical activity, leadership, and communication skills. Page 84 2012 Appalachian Student Research Forum Control group participants receive their regularly scheduled Lifetime Wellness curriculum. Body mass index percentile, dietary behavior, and physical activity among study subjects will be assessed at baseline, and at three and twelve months post-baseline. In addition, peer group norms, body image, supportive peer relationships, role modeling, behavioral control/self-efficacy, attitudes, and intentions toward healthy eating and physical activity will also be assessed. Group differences will be assessed at each data collection period. The long-term goal of the study is to establish an effective academia-community partnership program to address adolescent obesity disparity in Southern Appalachia

Breast cancer diagnosis using scattered X-rays

Small-angle X-ray diffraction data has been collected from 99 `core-cut' breast tissue specimens representing a number of different pathologies. Data in the range 75–1390 Å have been compared with controls from patients with no breast disease. Bessel functions and Bragg maxima resulting from the fibrillar structure of collagen have been identified. The Bragg maxima indexed onto a 649 Å lattice. Systematic differences in the intensities and D-spacings between the collagen of malignant, benign and normal tissue groups have been clearly demonstrated and quantified. These differences appear to be due to a significantly lower structural order within the malignant tissues. Possible explanations for this are discussed and the potential for utilizing this observation in cancer diagnosis is considered

Preliminary observations of breast tumor collagen using synchrotron radiation

The most frequently occurring cancer in women is that of the breast where it accounts for almost 20% of all cancer deaths. The U.K. has the world's highest mortality rate from breast cancer with an increasing incidence of 25000 per annum. Characterizing the complex physiological and tissue changes that form the natural history of breast cancer is clearly important for understanding associated biological mechanisms and for diagnosis. We report the initial findings of a diffraction study of breast tissue collagen that we believe may be due to tumor genesis. Small angle, synchrotron X-ray scattering has enabled us to examine `core cut' biopsy specimens and characterize their collagen architecture. We present data that demonstrates possible structural differences between tumor and normal tissue. We discuss the implications of these findings in the context of using molecular structure characteristics as new and novel markers of disease progression

Thigh-length compression stockings and DVT after stroke

Controversy exists as to whether neoadjuvant chemotherapy improves survival in patients with invasive bladder cancer, despite randomised controlled trials of more than 3000 patients. We undertook a systematic review and meta-analysis to assess the effect of such treatment on survival in patients with this disease

Evolution of a Distinct Genomic Domain in Drosophila: Comparative Analysis of the Dot Chromosome in Drosophila melanogaster and Drosophila virilis

The distal arm of the fourth (“dot”) chromosome of Drosophila melanogaster is unusual in that it exhibits an amalgamation of heterochromatic properties (e.g., dense packaging, late replication) and euchromatic properties (e.g., gene density similar to euchromatic domains, replication during polytenization). To examine the evolution of this unusual domain, we undertook a comparative study by generating high-quality sequence data and manually curating gene models for the dot chromosome of D. virilis (Tucson strain 15010–1051.88). Our analysis shows that the dot chromosomes of D. melanogaster and D. virilis have higher repeat density, larger gene size, lower codon bias, and a higher rate of gene rearrangement compared to a reference euchromatic domain. Analysis of eight “wanderer” genes (present in a euchromatic chromosome arm in one species and on the dot chromosome in the other) shows that their characteristics are similar to other genes in the same domain, which suggests that these characteristics are features of the domain and are not required for these genes to function. Comparison of this strain of D. virilis with the strain sequenced by the Drosophila 12 Genomes Consortium (Tucson strain 15010–1051.87) indicates that most genes on the dot are under weak purifying selection. Collectively, despite the heterochromatin-like properties of this domain, genes on the dot evolve to maintain function while being responsive to changes in their local environment