Distribution and Population Structure of Freshwater Mussels (Unionidae) in Lake Chicot, Arkansas

A systematic survey of mussel concentrations (= beds) in Lake Chicot was conducted during June 10-15, 1991. The lake was divided into 58 relatively equal-sized quadrats for qualitative survey by two, 2-man teams using Hookah dive systems. A qualitative survey revealed a single mussel bed encompassing an area approximately 12 km long and four m wide. For population analysis, the bed was sub-divided into five strata encompassing 9600 m2 each. Twenty random, 4 x 1 m, quantitative samples were taken from each of the five strata. Four mussel taxa; Amblema plicata (threeridge), Quadrula quadrula (mapleleaf) Quadrula nodulata (wartyback), and Plectomerus dombeyanus (bankclimber), accounted for 99.6% of the specimens sampled. The total mussel population for the bed was estimated to be 59,304 + 8,392. Potential for commercial harvest of Lake Chicot mussel resources is minimal at this time due to small shell size and poor shell quality

Ami - The Chemist's Amanuensis

RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.Abstract The Ami project was a six month Rapid Innovation project sponsored by JISC to explore the Virtual Research Environment space. The project brainstormed with chemists and decided to investigate ways to facilitate monitoring and collection of experimental data. A frequently encountered use-case was identified of how the chemist reaches the end of an experiment, but finds an unexpected result. The ability to replay events can significantly help make sense of how things progressed. The project therefore concentrated on collecting a variety of dimensions of ancillary data - data that would not normally be collected due to practicality constraints. There were three main areas of investigation: 1) Development of a monitoring tool using infrared and ultrasonic sensors; 2) Time-lapse motion video capture (for example, videoing 5 seconds in every 60); and 3) Activity-driven video monitoring of the fume cupboard environs. The Ami client application was developed to control these separate logging functions. The application builds up a timeline of the events in the experiment and around the fume cupboard. The videos and data logs can then be reviewed after the experiment in order to help the chemist determine the exact timings and conditions used. The project experimented with ways in which a Microsoft Kinect could be used in a laboratory setting. Investigations suggest that it would not be an ideal device for controlling a mouse, but it shows promise for usages such as manipulating virtual molecules.Peer Reviewe

Sleeping Beauty screen reveals Pparg activation in metastatic prostate cancer

Prostate cancer (CaP) is the most common adult male cancer in the developed world. The paucity of biomarkers to predict prostate tumor biology makes it important to identify key pathways that confer poor prognosis and guide potential targeted therapy. Using a murine forward mutagenesis screen in a Pten-null background, we identified peroxisome proliferator-activated receptor gamma (Pparg), encoding a ligand-activated transcription factor, as a promoter of metastatic CaP through activation of lipid signaling pathways, including up-regulation of lipid synthesis enzymes [fatty acid synthase (FASN), acetyl-CoA carboxylase (ACC), ATP citrate lyase (ACLY)]. Importantly, inhibition of PPARG suppressed tumor growth in vivo, with down-regulation of the lipid synthesis program. We show that elevated levels of PPARG strongly correlate with elevation of FASN in human CaP and that high levels of PPARG/FASN and PI3K/pAKT pathway activation confer a poor prognosis. These data suggest that CaP patients could be stratified in terms of PPARG/FASN and PTEN levels to identify patients with aggressive CaP who may respond favorably to PPARG/FASN inhibition

Revised Status of Rare and Endangered Unionaea (Mollusca: Margaritiferidae, Unionidae) in Arkansas

Harris and Gordon (1987) reviewed the distribution and status of 18 rare and /or endangered unionacean bivalve species (commonly referred to as clams, mussels, freshwater mussels, naiads) that occur or have occurred in Arkansas. They discussed four species that were federally listed as endangered, four species that were considered endangered or extirpated within Arkansas, four species considered threatened within Arkansas, four species of special concern within Arkansas, and two species for which the conservation status was considered uncertain due to questions regarding taxonomic validity. Numerous unionacean field surveys have been performed during 1986 1996, and a substantial database of new distributional and relative abundance information has been accumulated. Two additional unionacean species have been listed as federally endangered, one additional species has been listed as federally threatened, and one endangered species has been newly discovered within Arkansas bringing the total number of federally protected unionacean species occurring within Arkansas to eight. The conservation status of 16 additional unionacean species occurring in Arkansas is discussed also

Growth Curves of Four Species of Commercially Valuable Freshwater Mussels (Bivalva: Unionidae)

North American freshwater mussels (Bivalvia: Unionidae) have been exploited commercially for over 100 years and have been regulated using shell size limits and/or harvest seasons. Presently, freshwater mussels are considered a threatened faunal group in North America due to the large numbers of endangered, threatened or special concern species. Therefore, management of this fauna should emphasize their long-term sustainability. The objectives of this study were 1) to construct von Bertalanffy growth curves for selected commercially-most-valuable species, Fusconaia ebena, Megalonaias nervosa, Amblema plicata and Quadrula quadrula, from five rivers and two reservoirs, 2) to compare species-specific von Bertalanffy growth curves from different rivers and reservoirs, and 3) to provide information on size at onset of sexual maturity in F. ebena and A. plicata. Von Bertalanffy growth curves of four commercially valuable Ambleminae species were used in this study to compare drainage-specific growth. Growth curves for all four species investigated were significantly different between pairs of drainages. Approximate size at onset of sexual maturity was determined for Arkansas F. ebena and A. plicata. Von Bertalanffy growth curves, coupled with life history and population dynamics information, could be useful in assessing and determining national/state harvest sizes and/or drainage specific harvest sizes once annual growth line formation is confirmed

MACiE (Mechanism, Annotation and Classification in Enzymes): novel tools for searching catalytic mechanisms

MACiE (Mechanism, Annotation and Classification in Enzymes) is a database of enzyme reaction mechanisms, and is publicly available as a web-based data resource. This paper presents the first release of a web-based search tool to explore enzyme reaction mechanisms in MACiE. We also present Version 2 of MACiE, which doubles the dataset available (from Version 1). MACiE can be accessed fro

Structure of the trypanosome transferrin receptor reveals mechanisms of ligand recognition and immune evasion.

To maintain prolonged infection of mammals, African trypanosomes have evolved remarkable surface coats and a system of antigenic variation1. Within these coats are receptors for macromolecular nutrients such as transferrin2,3. These must be accessible to their ligands but must not confer susceptibility to immunoglobulin-mediated attack. Trypanosomes have a wide host range and their receptors must also bind ligands from diverse species. To understand how these requirements are achieved, in the context of transferrin uptake, we determined the structure of a Trypanosoma brucei transferrin receptor in complex with human transferrin, showing how this heterodimeric receptor presents a large asymmetric ligand-binding platform. The trypanosome genome contains a family of around 14 transferrin receptors4, which has been proposed to allow binding to transferrin from different mammalian hosts5,6. However, we find that a single receptor can bind transferrin from a broad range of mammals, indicating that receptor variation is unlikely to be necessary for promiscuity of host infection. In contrast, polymorphic sites and N-linked glycans are preferentially found in exposed positions on the receptor surface, not contacting transferrin, suggesting that transferrin receptor diversification is driven by a need for antigenic variation in the receptor to prolong survival in a host

The Evolution of Sunspot Magnetic Fields Associated with a Solar Flare

Solar flares occur due to the sudden release of energy stored in active-region magnetic fields. To date, the pre-cursors to flaring are still not fully understood, although there is evidence that flaring is related to changes in the topology or complexity of an active region's magnetic field. Here, the evolution of the magnetic field in active region NOAA 10953 was examined using Hinode/SOT-SP data, over a period of 12 hours leading up to and after a GOES B1.0 flare. A number of magnetic-field properties and low-order aspects of magnetic-field topology were extracted from two flux regions that exhibited increased Ca II H emission during the flare. Pre-flare increases in vertical field strength, vertical current density, and inclination angle of ~ 8degrees towards the vertical were observed in flux elements surrounding the primary sunspot. The vertical field strength and current density subsequently decreased in the post-flare state, with the inclination becoming more horizontal by ~7degrees. This behaviour of the field vector may provide a physical basis for future flare forecasting efforts.Comment: Accepted for Publication in Solar Physics. 16 pages, 4 figure