Chelae asymmetry and trematode parasite load in the crayfish Orconectes virilis.

Natural History & EvolutionFluctuating asymmetry (FA) is random departure from perfect bilateral symmetry of a morphological trait and is hypothesized to be a result of genetics and environmental stress. Parasites play an important role in the development of phenotypic traits, since the full expression of certain traits may reflect the ability of hosts to cope with the debilitating effects of parasites. In our study, we tested the relationship between degree of FA in chelae of North American freshwater crayfish (Orconectes virilis) and the magnitude of metacercarae parasite infection (Microphallus spp.). Crayfish were collected at two lakes near Pellston, Michigan. We measured chelae length and width and counted the number of metacercariae found in crayfish liver. Our results showed a significant positive correlation between parasite load and chelae width asymmetry, which previous studies have not measured, however, no correlation was found between parasite load and chelae length asymmetry. Our results suggest either that less symmetrical individuals are more susceptible to parasites or that parasitism causes developmental stress in hosts, or both, and that chelae width is more affected by parasite load than chelae length because of its importance in agonistic behaviors.http://deepblue.lib.umich.edu/bitstream/2027.42/78469/1/McClure_Nguyen_2010.pd

Assessment of DNA extracted from FTA® cards for use on the Illumina iSelect BeadChip

<p>Abstract</p> <p>Background</p> <p>As FTA^®cards provide an ideal medium for the field collection of DNA we sought to assess the quality of genomic DNA extracted from this source for use on the Illumina BovineSNP50 iSelect BeadChip which requires unbound, relatively intact (fragment sizes ≥ 2 kb), and high-quality DNA. Bovine blood and nasal swab samples collected on FTA cards were extracted using the commercially available GenSolve kit with a minor modification. The call rate and concordance of genotypes from each sample were compared to those obtained from whole blood samples extracted by standard PCI extraction.</p> <p>Findings</p> <p>An ANOVA analysis indicated no significant difference (P > 0.72) in BovineSNP50 genotype call rate between DNA extracted from FTA cards by the GenSolve kit or extracted from whole blood by PCI. Two sample t-tests demonstrated that the DNA extracted from the FTA cards produced genotype call and concordance rates that were not different to those produced by assaying DNA samples extracted by PCI from whole blood.</p> <p>Conclusion</p> <p>We conclude that DNA extracted from FTA cards by the GenSolve kit is of sufficiently high quality to produce results comparable to those obtained from DNA extracted from whole blood when assayed by the Illumina iSelect technology. Additionally, we validate the use of nasal swabs as an alternative to venous blood or buccal samples from animal subjects for reliably producing high quality genotypes on this platform.</p

Context matters: Construct framing in measures of physical activity engagement among African American women

Assessment of psychosocial factors influencing health behavior typically privileges conceptual consistency (framing constructs similarly across contexts) over conceptual specificity (context-specific framing). Modest statistical relationships between these factors and health behaviors, and persistent racial disparities in health outcomes raise questions about whether conceptually consistent framing fully captures relevant predictors. Ethnographic studies suggest not - that perceptions influencing health behaviors are multifaceted and contextual. To test this, we added items querying contextualized predictors of intention to engage in leisure-time physical activity (LTPA) to a Theory of Planned Behavior (TPB)-based survey and examined the psychometrics of the adapted subscales. We measured internal consistency (Cronbach’s alpha) and construct validity (exploratory factor analysis using polychoric correlations for ordinal data). Participants were a convenience sample of 200 African American women in a Midwestern, suburban University-affiliated family medicine practice. Reliability of the adapted subscales was notably lower than the original subscales. A two-factor model fit best for the attitudes subscale, but explained slightly less than 50% of the variance. The new items loaded strongly on one factor. A three-factor model best fit the norms subscale and accounted for around 57% of the variance. Two of the three new items loaded strongly on one factor. Factor analysis for the perceived control subscale was not possible due to low number of items; however, two of the three new items were highly correlated (.73). Including context-specific factors may improve assessment of intention to engage in LTPA. Further study of this question with a larger, representative sample is warranted

Changing the conversation about prostate cancer among African Americans: results of formative research

Objectives: To understand obstacles to and opportunities for improving prostate cancer communication to and within African American communities. Design: Researchers conducted interviews with 19 community leaders and five focus groups with healthy men and survivors. The team also conducted process evaluations of two outreach projects in which survivors spoke to African American men about prostate cancer and screening. Results: Three levels of obstacles to prostate cancer screening and treatment were identified. Individual-level obstacles included limited knowledge about the condition, about prevention and treatment, and fear of cancer. Socio-cultural barriers included distrust of the medical system, lack of a provider for routine and preventive care, reluctance to talk about cancer, and aversion to aspects of screening. Institutional deficits included the scarcity of educational efforts targeting prostate cancer. Outreach project evaluations suggested that survivors can be effective in building prostate cancer knowledge, promoting positive attitudes toward screening, and fostering conversations about prostate cancer. Educational efforts included little information about screening risks and decision-making however. Conclusions: The findings suggest that most potent interventions may combine survivor-led education with mass media and institution-based outreach. Such comprehensive programs could shift social norms that inhibit conversation and foster fear, leading in turn to more informed decisions and better treatment outcomes

Baylisascaris procyonis in the Metropolitan Atlanta Area

Baylisascaris procyonis, the raccoon roundworm responsible for fatal larva migrans in humans, has long been thought to be absent from many regions in the southeastern United States. During spring 2002, 11 (22%) of 50 raccoons trapped in DeKalb County, Georgia, had B. procyonis infection. The increasing number of cases highlight this emerging zoonotic infection

Sera selected from national STI surveillance system shows Chlamydia trachomatis PgP3 antibody correlates with time since infection and number of previous infections

Pgp3 seropositivity by time since most recent chlamydia diagnosis on a) the indirect ELISA and b) the double-antigen ELISA (Denominator labelled on bar. Error bars represent 95% confidence intervals).</p

Fluorescence-based endoscopic imaging of Thomsen–Friedenreich antigen to improve early detection of colorectal cancer

Thomsen–Friedenreich (TF) antigen belongs to the mucin-type tumor-associated carbohydrate antigen. Notably, TF antigen is overexpressed in colorectal cancer (CRC) but is rarely expressed in normal colonic tissue. Increased TF antigen expression is associated with tumor invasion and metastasis. In this study, we sought to validate a novel nanobeacon for imaging TF-associated CRC in a preclinical animal model. We developed and characterized the nanobeacon for use with fluorescence colonoscopy. In vivo imaging was performed on an orthotopic rat model of CRC. Both white light and fluorescence colonoscopy methods were utilized to establish the ratio-imaging index for the probe. The nanobeacon exhibited specificity for TF-associated cancer. Fluorescence colonoscopy using the probe can detect lesions at the stage which is not readily confirmed by conventional visualization methods. Further, the probe can report the dynamic change of TF expression as tumor regresses during chemotherapy. Data from this study suggests that fluorescence colonoscopy can improve early CRC detection. Supplemented by the established ratio-imaging index, the probe can be used not only for early detection, but also for reporting tumor response during chemotherapy. Furthermore, since the data obtained through in vivo imaging confirmed that the probe was not absorbed by the colonic mucosa, no registered toxicity is associated with this nanobeacon. Taken together, these data demonstrate the potential of this novel probe for imaging TF antigen as a biomarker for the early detection and prediction of the progression of CRC at the molecular level

Accuracies of genomic breeding values in American Angus beef cattle using K-means clustering for cross-validation

<p>Abstract</p> <p>Background</p> <p>Genomic selection is a recently developed technology that is beginning to revolutionize animal breeding. The objective of this study was to estimate marker effects to derive prediction equations for direct genomic values for 16 routinely recorded traits of American Angus beef cattle and quantify corresponding accuracies of prediction.</p> <p>Methods</p> <p>Deregressed estimated breeding values were used as observations in a weighted analysis to derive direct genomic values for 3570 sires genotyped using the Illumina BovineSNP50 BeadChip. These bulls were clustered into five groups using K-means clustering on pedigree estimates of additive genetic relationships between animals, with the aim of increasing within-group and decreasing between-group relationships. All five combinations of four groups were used for model training, with cross-validation performed in the group not used in training. Bivariate animal models were used for each trait to estimate the genetic correlation between deregressed estimated breeding values and direct genomic values.</p> <p>Results</p> <p>Accuracies of direct genomic values ranged from 0.22 to 0.69 for the studied traits, with an average of 0.44. Predictions were more accurate when animals within the validation group were more closely related to animals in the training set. When training and validation sets were formed by random allocation, the accuracies of direct genomic values ranged from 0.38 to 0.85, with an average of 0.65, reflecting the greater relationship between animals in training and validation. The accuracies of direct genomic values obtained from training on older animals and validating in younger animals were intermediate to the accuracies obtained from K-means clustering and random clustering for most traits. The genetic correlation between deregressed estimated breeding values and direct genomic values ranged from 0.15 to 0.80 for the traits studied.</p> <p>Conclusions</p> <p>These results suggest that genomic estimates of genetic merit can be produced in beef cattle at a young age but the recurrent inclusion of genotyped sires in retraining analyses will be necessary to routinely produce for the industry the direct genomic values with the highest accuracy.</p

Novel analytical method, Birth Date Selection Mapping, detects response of the Angus (Bos taurus) genome to selection on complex traits

Background: Several methods have recently been developed to identify regions of the genome that have been exposed to strong selection. However, recent theoretical and empirical work suggests that polygenic models are required to identify the genomic regions that are more moderately responding to ongoing selection on complex traits. We examine the effects of multi-trait selection on the genome of a population of US registered Angus beef cattle born over a 50-year period representing approximately 10 generations of selection. We present results from the application of a quantitative genetic model, called Birth Date Selection Mapping, to identify signatures of recent ongoing selection.Results: We show that US Angus cattle have been systematically selected to alter their mean additive genetic merit for most of the 16 production traits routinely recorded by breeders. Using Birth Date Selection Mapping, we estimate the time-dependency of allele frequency for 44,817 SNP loci using genomic best linear unbiased prediction, generalized least squares, and BayesCpi analyses. Finally, we reconstruct the primary phenotypes that have historically been exposed to selection from a genome-wide analysis of the 16 production traits and gene ontology enrichment analysis.Conclusions: We demonstrate that Birth Date Selection Mapping utilizing mixed models corrects for time-dependent pedigree sampling effects that lead to spurious SNP associations and reveals genomic signatures of ongoing selection on complex traits. Because multiple traits have historically been selected in concert and most quantitative trait loci have small effects, selection has incrementally altered allele frequencies throughout the genome. Two quantitative trait loci of large effect were not the most strongly selected of the loci due to their antagonistic pleiotropic effects on strongly selected phenotypes. Birth Date Selection Mapping may readily be extended to temporally-stratified human or model organism populations.Peer reviewedAnimal Scienc