Identification of Differential Agronomic Traits in Early Stage Teosinte, Flint, Dent, and Sugar (Sweet) Corn Varieties in Competition with Weeds

Weed competition reduces corn yield. Today’s corn monoculture relies heavily on herbicide inputs to maintain yield. However, teosinte, corn’s ancestor, was successfully grown in mixed production systems. Harnessing genes and traits that allow teosinte to be a better competitor but which may have been lost during corn domestication could help producers reduce herbicide inputs and maintain yield. The first step to finding those genes is to identify varieties of corn and lines of teosinte that have a higher tolerance of weeds or greater weed suppressive ability. Five introductions of teosinte and 14 varieties of corn (including dent, heritage, and sweet corn types) were cultivated with and without weed pressure. Early and end of season growth characteristics including leaf area, plant height, stem diameter, biomass, and yield, when possible, indicated a wide range of weed tolerance. Differences between weedy and weed-free treatments within a type ranged from 1-10% in corn height, 3-20% in leaf area, 1-27% in corn biomass (July), 0.4-28% in top collar height (September), and 2-17% in grain yield on a per cob basis at harvest (October). Varieties demonstrating the greatest and least deviations in these measurements between treatments have been selected for preliminary molecular analysis (data not available at this time). Identifying early season growth characteristics and gene expression associated with maintaining high yield under weed stress conditions can, in the long term, lead to better understanding the mechanisms of crop tolerance, its heritability, and reducing weed control inputs

A Study of Lyman-Alpha Quasar Absorbers in the Nearby Universe

Spectroscopy of ten quasars obtained with the Goddard High Resolution Spectrograph (GHRS) of the Hubble Space Telescope (HST) is presented. A clustering analysis reveals an excess of nearest neighbor line pairs on velocity scales of 250-750 km/s at a 95-98% confidence level. The hypothesis that the absorbers are randomly distributed in velocity space can be ruled out at the 99.8% confidence level. No two-point correlation power is detected (xi < 1 with 95% confidence). Lyman-alpha absorbers have correlation amplitudes on scales of 250-500 km/s at least 4-5 times smaller than the correlation amplitude of bright galaxies. A detailed comparison between absorbers in nearby galaxies is carried out on a limited subset of 11 Lyman- alpha absorbers where the galaxy sample in a large contiguous volume is complete to M_B = -16. Absorbers lie preferentially in regions of intermediate galaxy density but it is often not possible to uniquely assign a galaxy counterpart to an absorber. This sample provides no explicit support for the hypothesis that absorbers are preferentially associated with the halos of luminous galaxies. We have made a preliminary comparison of the absorption line properties and environments with the results of hydrodynamic simulations. The results suggest that the Lyman-alpha absorbers represent diffuse or shocked gas in the IGM that traces the cosmic web of large scale structure. (abridged)Comment: 36 pages of text, 15 figures, 4 tables, 36 file

IView: introgression library visualization and query tool

<p>Abstract</p> <p>Background</p> <p>An introgression library is a family of near-isogenic lines in a common genetic background, each of which carries one or more genomic regions contributed by a donor genome. Near-isogenic lines are powerful genetic resources for the analysis of phenotypic variation and are important for map-base cloning genes underlying mutations and traits. With many thousands of distinct genotypes, querying introgression libraries for lines of interest is an issue. </p> <p>Results</p> <p>We have created IView, a tool to graphically display and query near-isogenic line libraries for specific introgressions. This tool incorporates a web interface for displaying the location and extent of introgressions. Each genetic marker is associated with a position on a reference map. Users can search for introgressions using marker names, or chromosome number and map positions. This search results in a display of lines carrying an introgression at the specified position. Upon selecting one of the lines, color-coded introgressions on all chromosomes of the line are displayed graphically.</p> <p>The source code for IView can be downloaded from <url>http://xrl.us/iview</url>. </p> <p>Conclusions</p> <p>IView will be useful for those wanting to make introgression data from their stock of germplasm searchable. </p

Hybrid Decay: A Transgenerational Epigenetic Decline in Vigor and Viability Triggered in Backcross Populations of Teosinte with Maize.

In the course of generating populations of maize with teosinte chromosomal introgressions, an unusual sickly plant phenotype was noted in individuals from crosses with two teosinte accessions collected near Valle de Bravo, Mexico. The plants of these Bravo teosinte accessions appear phenotypically normal themselves and the F1 plants appear similar to typical maize × teosinte F1s. However, upon backcrossing to maize, the BC1 and subsequent generations display a number of detrimental characteristics including shorter stature, reduced seed set, and abnormal floral structures. This phenomenon is observed in all BC individuals and there is no chromosomal segment linked to the sickly plant phenotype in advanced backcross generations. Once the sickly phenotype appears in a lineage, normal plants are never again recovered by continued backcrossing to the normal maize parent. Whole-genome shotgun sequencing reveals a small number of genomic sequences, some with homology to transposable elements, that have increased in copy number in the backcross populations. Transcriptome analysis of seedlings, which do not have striking phenotypic abnormalities, identified segments of 18 maize genes that exhibit increased expression in sickly plants. A de novo assembly of transcripts present in plants exhibiting the sickly phenotype identified a set of 59 upregulated novel transcripts. These transcripts include some examples with sequence similarity to transposable elements and other sequences present in the recurrent maize parent (W22) genome as well as novel sequences not present in the W22 genome. Genome-wide profiles of gene expression, DNA methylation, and small RNAs are similar between sickly plants and normal controls, although a few upregulated transcripts and transposable elements are associated with altered small RNA or methylation profiles. This study documents hybrid incompatibility and genome instability triggered by the backcrossing of Bravo teosinte with maize. We name this phenomenon "hybrid decay" and present ideas on the mechanism that may underlie it

A Rare Case of Double Belly Soleus Muscle

The rare anatomical anomaly of a double belly soleus muscle has been associated with some clinical and non-clinical correlations in patients. With symptomatic patients, usually not presenting until 20–30 years old, pain is exacerbated by long walks, running, and standing for long periods of time. This presentation could mimic the properties of a soft tissue tumor, thus misleading physicians. The discovery of the double belly soleus muscle is noticed while in surgery, biopsy, computed tomography scan, or magnetic resonance imaging machine. We herewith present a rare case of double belly soleus on the left and right posterior lower leg region of a 58-year-old female cadaver. This article will help bring awareness to the signs and symptoms of this rare anatomical anomaly

Contribution of commuting to total daily moderate-to-vigorous physical activity

Background: Actively commuting to and from work can increase moderate-to-vigorous physical activity (MVPA) and increase adherence to physical activity (PA) guidelines; however, there is a lack of evidence on the contribution of mixed-mode commutes and continuous stepping bouts to PA. Many commuting studies employ the use of self-reported PA measures. This study objectively determined the contribution of MVPA during commuting to total MVPA, using cadence to define MVPA, and explored how the length of stepping bouts affects adherence to PA guidelines. Methods: Twenty-seven university staff wore an activPAL™ activity monitor for seven days and kept an activity diary. The activPAL™quantified MVPA and bouts duration and the activity diary collected information about commute times and the modes of commute. Twenty-three participants with at least four days of data were included in the final analysis. Results: The median total time per day spent in MVPA was 49.6 (IQR: 27.4–75.8) minutes and 31% of the total time was accumulated during commuting (median = 15.2 minutes; IQR: 4.11–26.9). Walking and mixed-mode commuters spent more time in MVPA (37.6 and 26.9 minutes, respectively), compared to car commuters (5.8 minutes). Seventeen out of the 23 participants achieved more than 30 minutes of MVPA per day, with five achieving this in their commute alone. A significant positive association was found between commute time spent in MVPA and total MVPA (p < .001). Conclusion: Commuting can be a major contributor to total MVPA, with the mode of commute having a significant role in the level of this contribution to total MVPA

Evaluation of bacterial biomarkers to aid in challenging inflammatory bowel diseases diagnostics and subtype classification

Supported by the Spanish Ministry of Education and Science, No. SAF2010-15896, No. SAF2013-43284-P and No. SAF2017-82261-P.Peer reviewedPostprintPublisher PD

Impact of carbohydrate substrate complexity on the diversity of the human colonic microbiota.

The diversity of the colonic microbial community has been linked with health in adults and diet composition is one possible determinant of diversity. We used carefully controlled conditions in vitro to determine how the complexity and multiplicity of growth substrates influence species diversity of the human colonic microbiota. In each experiment, five parallel anaerobic fermenters that received identical faecal inocula were supplied continuously with single carbohydrates (either arabinoxylan-oligosaccharides (AXOS), pectin or inulin) or with a '3-mix' of all three carbohydrates, or with a '6-mix' that additionally contained resistant starch, β-glucan and galactomannan as energy sources. Inulin supported less microbial diversity over the first 6 d than the other two single substrates or the 3- and 6-mixes, showing that substrate complexity is key to influencing microbiota diversity. The communities enriched in these fermenters did not differ greatly at the phylum and family level, but were markedly different at the species level. Certain species were promoted by single substrates, whilst others (such as Bacteroides ovatus, LEfSe P = 0.001) showed significantly greater success with the mixed substrate. The complex polysaccharides such as pectin and arabinoxylan-oligosaccharides promoted greater diversity than simple homopolymers, such as inulin. These findings suggest that dietary strategies intended to achieve health benefits by increasing gut microbiota diversity should employ complex non-digestible substrates and substrate mixtures