Vertebrate DM domain proteins bind similar DNA sequences and can heterodimerize on DNA

<p>Abstract</p> <p>Background:</p> <p>The DM domain is a zinc finger-like DNA binding motif first identified in the sexual regulatory proteins Doublesex (DSX) and MAB-3, and is widely conserved among metazoans. DM domain proteins regulate sexual differentiation in at least three phyla and also control other aspects of development, including vertebrate segmentation. Most DM domain proteins share little similarity outside the DM domain. DSX and MAB-3 bind partially overlapping DNA sequences, and DSX has been shown to interact with DNA via the minor groove without inducing DNA bending. DSX and MAB-3 exhibit unusually high DNA sequence specificity relative to other minor groove binding proteins. No detailed analysis of DNA binding by the seven vertebrate DM domain proteins, DMRT1-DMRT7 has been reported, and thus it is unknown whether they recognize similar or diverse DNA sequences.</p> <p>Results:</p> <p>We used a random oligonucleotide in vitro selection method to determine DNA binding sites for six of the seven proteins. These proteins selected sites resembling that of DSX despite differences in the sequence of the DM domain recognition helix, but they varied in binding efficiency and in preferences for particular nucleotides, and some behaved anomalously in gel mobility shift assays. DMRT1 protein from mouse testis extracts binds the sequence we determined, and the DMRT proteins can bind their in vitro-defined sites in transfected cells. We also find that some DMRT proteins can bind DNA as heterodimers.</p> <p>Conclusion:</p> <p>Our results suggest that target gene specificity of the DMRT proteins does not derive exclusively from major differences in DNA binding specificity. Instead target specificity may come from more subtle differences in DNA binding preference between different homodimers, together with differences in binding specificity between homodimers versus heterodimers.</p

Effects of commercial clam aquaculture on biogeochemical cycling in shallow coastal ecosystems

The bivalve aquaculture industry is expanding worldwide; sustainability requires improved understanding of its interactions with the environment. As suspension feeders, bivalves, such as clams, reduce primary production through feeding, and thus dampen eutrophication. Additionally, enhanced rates of denitrification, the microbial removal of reactive nitrogen, have been reported in bivalve sediments due to increased organic matter supply through biodeposition; another potential, yet indirect, control on eutrophication. Simultaneously, bivalves can influence local ‘bottom-up’ effects on production by enhancing nutrient regeneration through excretion and microbial mineralization of biodeposits. At clam aquaculture sediments, respiration and nutrient regeneration rates were significantly higher compared to uncultivated sediments. The enhanced nutrient recycling facilitated by clam aquaculture directly fueled macroalgal production, which proliferate on the shallow predator-exclusion nets commonly used by US aquaculturists. The effect of clams on denitrification and dissimilatory nitrate reduction to ammonium (DNRA), microbial processes that compete for nitrate, was site and season dependent; strongly influenced by nitrate concentrations relative to organic carbon availability. DNRA was favored over denitrification in environments with low nitrate (i.e. Cherrystone Inlet, VA) while denitrification increased above DNRA in high nitrate conditions (i.e. low salinity sites in Sacca di Goro, Italy). As a bioextractive practice, bivalve aquaculture is a net sink for nitrogen via harvest, however, depending on the food source (e.g. external or internal), bivalves may increase nitrogen and subsequently production on a local scale. These results highlight the need to assess both nitrogen removal and regeneration pathways associated with bivalve aquaculture to determine the overall effect on eutrophication

Biological Fixed-Film Systems

The Microbiological Degradation of Wastewater and its Application using a Fixed-Film Reactor is Reviewed. the Technical and Technological Characteristics, as Well as the Efficiency of Nitrification and Denitrification Processes Were Taken into Consideration. the Review Elucidated the Experimental Measurements of Effective Diffusive Permeabilities and Effective Diffusion Coefficients of Biofilms

Competition for Andersen\u27s Clients

We examine competition for Andersen’s public clients during and after its failure in 2002. This setting provides a natural experiment to examine audit market dynamics at the local level. We construct a database documenting Big4 purchases of local Andersen offices. After exploring the factors associated with office purchases, we examine the impact of office purchases on public client market share gains and changes in audit fees. We find that three Big4 firms – Deloitte, Ernst & Young, and KPMG – purchased approximately 60% of Andersen’s offices while PricewaterhouseCoopers did not purchase any. The probability that a firm purchased a specific office is greater in markets where the acquiring firm: 1) already had a presence, 2) had a lower ratio of local Andersen clients to the purchaser’s clients, and 3) had already acquired relatively more local former Andersen public clients than other firms prior to the purchase. Our fee analysis expands the United States Government Accountability Office (GAO) post-Andersen audit market study by documenting that the former Andersen clients’ change in audit fees is associated with the differences in client acquisition method

The Effect of Ionic Dissolution Products of Ca-Sr-Na-Zn-Si Bioactive Glass on in Vitro Cytocompatibility

Many commercial bone grafts cannot regenerate healthy bone in place of diseased bone. Bioactive glasses have received much attention in this regard due to the ability of their ionic dissolution products to promote cell proliferation, cell differentiation and activate gene expression. Through the incorporation of certain ions, bioactive glasses can become therapeutic for specific pathological situations. Calcium-strontium-sodium-zinc-silicate glass bone grafts have been shown to release therapeutic levels of zinc and strontium, however the in vitro compatibility of these materials is yet to be reported. In this study, the in vitro cytocompatibility of three different calcium-strontium-sodium-zinc-silicate glasses was examined as a function of their ion release profiles, using Novabone® bioglass as a commercial comparison. Experimental compositions were shown to release Si4+ ranging from 1 to 81 ppm over 30 days; comparable or enhanced release in comparison to Novabone. The maximum Ca2+ release detected for experimental compositions was 9.1 ppm, below that reported to stimulate osteoblasts. Sr2+ release was within known therapeutic ranges, and Zn2+ release ranged from 0.5 to 1.4 ppm, below reported cytotoxic levels. All examined glass compositions show equivalent or enhanced in vitro compatibility in comparison to Novabone. Cells exposed to BT112 ionic products showed enhanced cell viabilities indicating cell proliferation was induced. The ion release profiles suggest this effect was due to a synergistic interaction between certain combinations and concentrations of ions. Overall, results indicate that the calcium-strontium-sodium-zinc-silicate glass compositions show equivalent or even enhanced in vitro compatibility compared to Novabone®. © 2010 Springer Science+Business Media, LLC

Accurate Determination of Phenotypic Information from Historic Thoroughbred Horses by Single Base Extension

Historic DNA have the potential to identify phenotypic information otherwise invisible in the historical, archaeological and palaeontological record. In order to determine whether a single nucleotide polymorphism typing protocol based on single based extension (SNaPshot™) could produce reliable phenotypic data from historic samples, we genotyped three coat colour markers for a sample of historic Thoroughbred horses for which both phenotypic and correct geotypic information were known from pedigree information in the General Stud Book. Experimental results were consistent with the pedigrees in all cases. Thus we demonstrate that historic DNA techniques can produce reliable phenotypic information from museum specimens.© 2010 Campana et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Conus Medullaris Enterogenous Cyst

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147142/1/pmr2698.pd

Instantaneous effects of mindfulness meditation on tennis return performance in elite junior athletes completing an implicitly sequenced serve return task

Single-session meditation augmentation of sport-specific skill performance was tested with elite junior tennis athletes. Athletes completed one of two styles of mindfulness meditation (focused-attention or open-monitoring) or a control listening condition prior to performing an implicitly sequenced tennis serve return task involving the goal of hitting a target area placed on the service court. Unbeknownst to athletes, six distinct serves followed a repeating second-order conditional sequence for two task blocks before the sequence was altered in a third transfer block. Task performance was operationalized as serve return outcome and analyzed using beta regression modeling. Models analyzed group by block differences in the proportion of returned serves (i.e., non-aces), returns placed in the service court, and target hits. Contrary to previous laboratory findings, results did not support meditation-related augmentation of performance and/or sequence learning. In fact, compared to control, meditation may have impaired performance improvements and acquisition of serve sequence information. It is possible that the effects of single-session meditation seen in laboratory research may not extend to more complex motor tasks, at least in highly-trained adolescents completing a well-learned skill. Further research is required to elucidate the participant, task, and meditation-related characteristics that might promote single-session meditation performance enhancement