Assessing Freshwater Mussel \u3cem\u3e(Bivalvia: Unionidae)\u3c/em\u3e Assemblages and Effects of Eutrophication on \u3cem\u3ePyganodon grandis\u3c/em\u3e in Lakes of Eastern South Dakota

Globally, the family Unionidae is the most threatened group of freshwater fauna. South Dakota is well known for its agricultural production, leading to cultural eutrophication from enhanced fertilizers and sediments. This impact can alter species presence, age, growth and mortality. Objectives of this study were to 1) implement the first comprehensive lake survey of freshwater mussels in eastern South Dakota lakes and document distribution, occurrence and relative abundance, 2) evaluate relationships between age, growth and mortality of Pyganodon grandis and lake trophic state. Freshwater mussels were sampled in 2017 from 116 proportionally and randomly selected natural lakes and reservoir basins throughout six major river basins of eastern South Dakota. We sampled a total of 1,789 specimens and nine unique species from two different orders. Mussel abundance was found to be negatively correlated with conductivity and positively correlate with lake transparency, whereas no significant relationships were found between mussel abundance and temperature, pH, dissolved oxygen or substrate particle size. Pyganodon grandis (Giant Floater) was the most abundant and frequently occurring species across all river basins and lake types. We also documented two invasive species during our sampling efforts, Dreissena polymorpha (Zebra Mussel) and Corbiula fluminea (Asian Clam). P. grandis from 21 survey sites were sectioned, aged and growth increments measured. The von Bertalanffy growth equation was utilized to evaluate growth rates and estimate length of natural lake and reservoir mussels. Mortality was assessed by implementing length-at-age keys to determine instantaneous and annual mortality rates. Age ranged from 4 to 11 years across all sampled sites. We found a significant negative relationship between P. grandis age and lake trophic state assessed from lake transparency data (R2= 0.394, p= 0.022). No significant relationships were observed for growth and mortality. There was a marginal significant difference observed in age based on lake type (p= 0.054). Results of this effort suggest that life expectancy is shorter in more culturally eutrophic lake basins and support results reported elsewhere. This study generated the first South Dakota unionid lake survey and future work can entail monitoring sensitive species and invasive species impacts to lakes

\u3cem\u3ePyganodon grandis\u3c/em\u3e growth along a trophic state gradient in Eastern South Dakota Lakes

https://openprairie.sdstate.edu/oak-lake_presentations/1007/thumbnail.jp

Harvester ant colony variation in foraging activity and response to humidity.

Collective behavior is produced by interactions among individuals. Differences among groups in individual response to interactions can lead to ecologically important variation among groups in collective behavior. Here we examine variation among colonies in the foraging behavior of the harvester ant, Pogonomyrmex barbatus. Previous work shows how colonies regulate foraging in response to food availability and desiccation costs: the rate at which outgoing foragers leave the nest depends on the rate at which foragers return with food. To examine how colonies vary in response to humidity and in foraging rate, we performed field experiments that manipulated forager return rate in 94 trials with 17 colonies over 3 years. We found that the effect of returning foragers on the rate of outgoing foragers increases with humidity. There are consistent differences among colonies in foraging activity that persist from year to year

Harvester Ant Colony Variation in Foraging Activity and Response to Humidity

<div><p>Collective behavior is produced by interactions among individuals. Differences among groups in individual response to interactions can lead to ecologically important variation among groups in collective behavior. Here we examine variation among colonies in the foraging behavior of the harvester ant, <i>Pogonomyrmex barbatus</i>. Previous work shows how colonies regulate foraging in response to food availability and desiccation costs: the rate at which outgoing foragers leave the nest depends on the rate at which foragers return with food. To examine how colonies vary in response to humidity and in foraging rate, we performed field experiments that manipulated forager return rate in 94 trials with 17 colonies over 3 years. We found that the effect of returning foragers on the rate of outgoing foragers increases with humidity. There are consistent differences among colonies in foraging activity that persist from year to year.</p></div

Data from: An experimental study of the putative mechanism of a synthetic autonomous rotary DNA nanomotor

DNA has been used to construct a wide variety of nanoscale molecular devices. Inspiration for such synthetic molecular machines is frequently drawn from protein motors, which are naturally occurring and ubiquitous. However, despite the fact that rotary motors such as ATP synthase and the bacterial flagellar motor play extremely important roles in nature, very few rotary devices have been constructed using DNA. This paper describes an experimental study of the putative mechanism of a rotary DNA nanomotor, which is based on strand displacement, the phenomenon that powers many synthetic linear DNA motors. Unlike other examples of rotary DNA machines, the device described here is designed to be capable of autonomous operation after it is triggered. The experimental results are consistent with operation of the motor as expected, and future work on an enhanced motor design may allow rotation to be observed at the single-molecule level. The rotary motor concept presented here has potential applications in molecular processing, DNA computing, biosensing and photonics

Strand displacement in a folded nanostructure (triangle)

QCM-D data in .csv format. File contains overtone-normalized frequency changes for thirteenth overtone as a function of time, with the corresponding dissipation changes. Data is provided for three cases: 1. triangle folded on surface and supplied with unfolded reverse complement of triangle. 2. pre-folded triangle supplied with unfolded reverse complement of triangle. 3. pre-folded triangle supplied with folded reverse complement of triangle

Myoscaffolds reveal laminin scarring is detrimental for stem cell function while sarcospan induces compensatory fibrosis.

We developed an on-slide decellularization approach to generate acellular extracellular matrix (ECM) myoscaffolds that can be repopulated with various cell types to interrogate cell-ECM interactions. Using this platform, we investigated whether fibrotic ECM scarring affected human skeletal muscle progenitor cell (SMPC) functions that are essential for myoregeneration. SMPCs exhibited robust adhesion, motility, and differentiation on healthy muscle-derived myoscaffolds. All SPMC interactions with fibrotic myoscaffolds from dystrophic muscle were severely blunted including reduced motility rate and migration. Furthermore, SMPCs were unable to remodel laminin dense fibrotic scars within diseased myoscaffolds. Proteomics and structural analysis revealed that excessive collagen deposition alone is not pathological, and can be compensatory, as revealed by overexpression of sarcospan and its associated ECM receptors in dystrophic muscle. Our in vivo data also supported that ECM remodeling is important for SMPC engraftment and that fibrotic scars may represent one barrier to efficient cell therapy