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The role of Hox genes in the development of insect gnathal appendages has been examined in three insects: the fruitfly, Drosophila melanogaster; the milkweed bug, Oncopeltus fasciatus; and the red flour beetle, Tribolium castaneum. In each of these organisms, the identity of the labium depends on the homeotic genes Sex combs reduced (Scr) and proboscipedia (pb). Loss of pb function in each of the three insects results in homeotic transformation of the labial appendages to legs. In contrast, loss of Scr function yields a different transformation in each species. Interestingly, mutations in Cephalothorax (Cx), the Tribolium ortholog of Scr, transform the labial appendages to antennae, a result seen in the other insects only when both pb and Scr are removed. We show here that the Tribolium labial appendages also develop as antennae in double mutants. Further, we demonstrate that expression of the Tribolium proboscipedia ortholog maxillopedia (mxp) is greatly reduced or absent in the labium of Cx mutant larvae. Thus, in the wild-type labial segment, Cx function is required (directly or indirectly) for mxp transcription. A similar interaction between Scr and pb during Drosophila embryogenesis has been described recently. Thus, this regulatory paradigm appears to be conserved at least within the Holometabola.

A genetic map of the red flour beetle (Tribolium castaneum) integrating molecular with morphological markers was constructed using a backcross population of 147 siblings. The map defines 10 linkage groups (LGs), presumably corresponding to the 10 chromosomes, and consists of 122 randomly amplified polymorphic DNA (RAPD) markers, six molecular markers representing identified genes, and five morphological markers. The total map length is 570 cM, giving an average marker resolution of 4.3 cM. The average physical distance per genetic distance was estimated at 350 kb/cM. A cluster of loci showing distorted segregation was detected on LG9. The process of converting RAPD markers to sequence-tagged site markers was initiated: 18 RAPD markers were cloned and sequenced, and single-strand conformational polymorphisms were identified for 4 of the 18. The map positions of all 4 coincided with those of the parent RAPD markers.

Despite the lack of objective evidence, spinal manual therapies have been common practice for many years, particularly for treatment of lower back pain (LBP). This exploratory study measured and analysed the effect of a spinal mobilisation intervention on muscle tissue quality in LBP sufferers. 40 people with LBP participated in a within-subject repeated measures cross-over study with intervention and control conditions. A myometer was used to assess the change in para-spinal muscle tissue quality before and after the intervention. Analysis considered the magnitude of muscle response together with individual covariates as potential contributors. A significant post-intervention reduction was observed in muscle stiffness (p = 0.012, η 2 partial = 0.15), tone (p = 0.001, η 2 partial = 0.25) and elasticity (p = 0.001, η 2 partial = 0.24). Significant increases were seen in 2 variables post-control: stiffness (p = 0.004, η 2 partial = 0.19), tone (p = 0.006, η 2 partial = 0.18) and a significant decrease in elasticity (p ˂ 0.000, η 2 partial = 0.3). Significant contributing covariates include baseline stiffness, BMI, waist circumference and sex. Baseline stiffness and tone were significantly correlated to their response levels. The significant reduction in all muscle tissue qualities following the intervention provide preliminary data for an evidence-based LBP therapeutic. Baseline stiffness, BMI, waist circumference and sex could act as significant contributors to magnitude of response. The results warrant further investigation into spinal mobilisation therapies to further build the objective evidence base. • Exploratory biomechanical investigation of spinal mobilisations in lower back pain sufferers. • Immediate and significant reduction revealed in myometry muscle stiffness and tone post intervention. • Statistical analysis of potential contributors to myometry muscle stiffness response. • Baseline stiffness levels revealed as significant contributor to level of change. [ABSTRACT FROM AUTHOR]

Leachate‐contaminated groundwater from historical municipal landfills, typically lacking engineered liners and leachate collection systems, poses a threat to nearby urban streams, particularly to benthic ecosystems. Effective monitoring and assessment of such sites requires understanding of the spatial patterns (i.e., two‐dimensional footprint) of contaminated groundwater discharge and associated controlling factors. However, discharges from groundwater contaminated by modern wastewater can complicate site assessments. The objectives of this study were to (1) demonstrate the use of artificial sweeteners (AS): saccharin (SAC), cyclamate (CYC), acesulfame (ACE), and sucralose (SUC), to distinguish groundwater discharge areas influenced by historic landfill leachate (elevated SAC and sometimes CYC; low ACE and SUC concentrations) from those influenced by wastewater (high ACE and SUC concentrations), and (2) investigate contaminant discharge patterns for two gaining urban stream reaches adjacent historic landfills at base flows. Contaminant discharge patterns revealed by the AS were strongly controlled by hyporheic flow (low AS concentrations), particularly for the straight reach, and stream sinuosity, particularly for the meandering reach. These patterns were different and the contaminant footprint coverage (<25% of streambed area) much less than most past studies (typically >50% coverage), likely due to the homogeneous streambed‐aquifer conditions and shallow, narrow landfill plume in this setting. [ABSTRACT FROM AUTHOR]

A recently isolated, lethal mutation of the homeotic Abdominal gene of the red flour beetle Tribolium castaneum is associated with an insertion of a novel retrotransposon into an intron. Sequence analysis indicates that this retrotransposon, named Woot, is a member of the gypsy family of mobile elements. Most strains of T. castaneum appear to harbor [approximately]25-35 copies of Woot per genome. Woot is composed of long terminal repeats of unprecedented length (3.6 kb each), flanking an internal coding region 5.0 kb in length. For most copies of Woot, the internal region includes two open reading frames (ORFs) that correspond to the gag and pol genes of previously described retrotransposons and retroviruses. The copy of Woot inserted into Abdominal bears an apparent single frameshift mutation that separates the normal second ORF into two. Woot does not appear to generate infectious virions by the criterion that no envelop gene is discernible. The association of Woot with a recent mutation suggests that this retroelement is currently transpositionally active in at least some strains.

Previous studies of the nutrient budgets of lakes in Precambrian Shield regions have generally ignored the role of groundwater as a source or sink (influx or efflux) of nutrients. This paper and its companion (Part 2) address this science gap by probing the role of groundwater in the nutrient balance for a restricted bay of a Precambrian Shield lake that has undergone extensive shoreline development. In Part 1, we introduce a conceptual model of the relevant processes, including the role of groundwater. A cottage study site is described, concentrations of nutrients and septic tracers (artificial sweeteners), water levels and other data are reported. This includes data from samples of the septic wastewater plume in groundwater at the cottage, and samples from the bay. The artificial sweetener data indicate seepage of septic plumes to the bay, but significant attenuation of septic-derived nutrients in the subsurface. These data are used for numerical modeling in Part 2. [ABSTRACT FROM AUTHOR]

Background: The lower Dipteran fungus fly, Sciara coprophila, has many unique biological features that challenge the rule of genome DNA constancy. For example, Sciara undergoes paternal chromosome elimination and maternal X chromosome nondisjunction during spermatogenesis, paternal X elimination during embryogenesis, intrachromosomal DNA amplification of DNA puff loci during larval development, and germline-limited chromosome elimination from all somatic cells. Paternal chromosome elimination in Sciara was the first observation of imprinting, though the mechanism remains a mystery. Here, we present the first draft genome sequence for Sciara coprophila to take a large step forward in addressing these features. Results: We assembled the Sciara genome using PacBio, Nanopore, and Illumina sequencing. To find an optimal assembly using these datasets, we generated 44 short-read and 50 long-read assemblies. We ranked assemblies using 27 metrics assessing contiguity, gene content, and dataset concordance. The highest-ranking assemblies were scaffolded using BioNano optical maps. RNA-seq datasets from multiple life stages and both sexes facilitated genome annotation. A set of 66 metrics was used to select the first draft assembly for Sciara. Nearly half of the Sciara genome sequence was anchored into chromosomes, and all scaffolds were classified as X-linked or autosomal by coverage. Conclusions: We determined that X-linked genes in Sciara males undergo dosage compensation. An entire bacterial genome from the Rickettsia genus, a group known to be endosymbionts in insects, was co-assembled with the Sciara genome, opening the possibility that Rickettsia may function in sex determination in Sciara. Finally, the signal level of the PacBio and Nanopore data support the presence of cytosine and adenine modifications in the Sciara genome, consistent with a possible role in imprinting. [ABSTRACT FROM AUTHOR]

Concepts and terms used in previous multidisciplinary studies of tile‐drained aquitard‐dominated catchments (TDADC) are inconsistent and confusing. We provide a well‐defined, comprehensive conceptual model of the subsurface hydrology of TDADC by selecting seven mutually compatible and consistent concepts. These concepts are: (1) groundwater as the main source of baseflow in headwater streams, (2) dominance of 'pre‐event' water in stormflow, (3) importance of both macropores and matrix, (4) changes in flowpaths with rate of stream discharge, (5) dominance of shallow, lateral subsurface flow, (6) interactive nature of subsurface water, (7) transpiration of groundwater. This conceptual model was successfully 'field‐tested' by examining data collected in a TDADC in a rural area of southern Ontario, Canada. The data consist mainly of chemical and isotopes tracers in water samples (headwater streams, groundwater, precipitation, tile water, soil‐surface water), supplemented by water levels and meteorological data. [ABSTRACT FROM AUTHOR]