Many rainbow trout (Oncorhynchus mykiss) populations exhibit partial migration, where resident and migrant individuals coexist in a single population. Due to anthropogenic, environmental, and population-specific factors, migratory individuals have been decreasing in frequency across the continental United States. Biologically, whether an individual will migrate is determined by both genetic and environmental factors. Although migration in many salmonids is known to be highly heritable, the environment plays an overriding role. Previous studies investigating the genetic basis of migration have failed to control for environmental variance and, consequently, the genes and regions of the genome underlying the development of the migratory phenotype remain unknown. We used data from a common garden experiment to identify single nucleotide polymorphisms (SNPs) significantly associated with migration in the F1 generation of a resident-by-resident and a migrant-by-migrant cross. We genotyped 192 F1 individuals on an Affymetrix SNP chip at 57,501 known polymorphic locations throughout the genome. We identified 5002 significant SNPs in the migrant-by-migrant family and 429 significant SNPs in the resident-by-resident family, using an FDR-corrected p-value of 0.01. For the migrant cross, we located significant markers associated with 28 genes whose functions are connected to pathways previously hypothesized to be important in migration. Five genes on three chromosomes were associated with migration in both familial crosses, suggesting that these regions are important in determining life history regardless of familial origin in this population. These data will be further used to develop a model to predict life history in individuals that are yet to make that determination. Understanding the genetic factors involved in the decision to migrate, through the identification of polymorphisms associated with migration, will assist fisheries managers in restoring and maintaining migratory rainbow trout populations.

The combination of inorganic porous silicon (pSi) and flexible biocompatible polymers has been shown to yield more beneficial hybrid scaffolds for tissue engineering (i.e. use of synthetic materials to facilitate healing). PSi has a variety of tunable properties, including pore size, pore volume and non-toxic degradation. The addition of a biocompatible polymer such as polycaprolactone (PCL) can provide control over shape and serve as an additional drug delivery component.
In this work, composite materials consisting of oxidized porous silicon (ox-pSi) with a particle size of ~ 30 μm and pore size of 40-100 nm and PCL porous fibers. Porous fibers were fabricated using an electrospinning method into sheets of desired thickness (0.1-0.4 mm), fiber diameter 3-4 μm, and fiber pore size 300-500 nm. Ox-pSi particles previously loaded with the anticancer drug-camptothecin (CPT) were placed between two sheets (6 mm in diameter each) and sealed at the edges, resulting in ~65% loading of ox-pSi. Drug release from the ox-pSi particles alone and ox-pSi/porous PCL fiber composites was monitored fluorometrically in phosphate buffered saline (PBS), showing a distinct release profile for each material.
Ox-pSi/p-PCL fiber composites release a CPT payload in accordance with the Higuchi release model and showed a significant decrease in burst effect compared to ox-pSi particles only. In addition, composite evolution after 5 weeks in PBS at 37 oC was examined using gravimetry, differential scanning calorimetry (DSC), and field emission scanning electron microscopy (FESEM). Overall weight loss of the composites was about 50%, mainly attributed to pSi particles dissolution and some polymer hydrolysis. Preliminary DSC results show that high surface area porous PCL fibers are less crystalline compared to solid PCL fibers, suggesting a faster hydrolysis route.

Europium contrast agents have been extensively investigated as an alternative to typical Gd3+ species for imaging. This is due to the dual imaging modalities which can accessed dependent on the oxidation state of the europium metal center (T1 or PARACEST). To achieve these functionalities, the europium containing complex must be stable enough to support both oxidation states (+3 and +2). In collaboration with UTSW, an electrochemical investigation was completed to understand the effects of the ligand environment on the metal center as a direct result of glycine modification to the ligand scaffold, DOTA. Increasing amide functionalities in close proximity to the europium core result in a positive shift in the potential in comparison to the acetate arms associated with DOTA. Furthermore, the addition of the glycine moiety to the pendant arms results in redox activity of the ligand itself, making the ligand non-innocent in nature. Additionally, a crystal structure of Eu4 (the tetraglycinate DOTA derivative) was obtained and compared to known lanthanide complexes.

Cerium (IV) oxide, or CeO2, nanomaterials have displayed antioxidant and enzyme mimetic activities due to a Ce3+/Ce4+ redox capability enhanced through oxygen vacancies and mobility. Tri-valent, fluorescent ions such as Eu3+ increase the Ce3+/Ce4+ ratio and oxygen vacancy concentration, while contributing fluorescent properties to the nanomaterial. The combination of these attributes make europium doped cerium oxide (EuCeO¬2) nanomaterials appealing candidates for various biological applications.
To complement our earlier efforts on the synthesis and properties of EuCeO2 nanowires, nanorods, and nanocubes, this presentation addresses a new, complementary structure, EuCeO2 nanotubes. The nanotubes are prepared via deposition and subsequent oxidation of Eu-doped Ce(OH)3 to form a EuCeO2 shell on sacrificial ZnO nanowires.
Previous synthetic routes to CeO2 nanotubes have been reported featuring carbon nanotubes as sacrificial templates, the etching of cerium-based nanorods, and other less-common methods . These routes have struggled with clear evidence for distinct nanotube formation, as well as control over nanotube dimensions. Our use of a ZnO core allows for facile manipulation of inner diameter and length of the nanotube following etching of the core.
The synthesized nanotubes were characterized using scanning and transmission microscopy (SEM and TEM) for morphology, energy dispersive x-ray (EDX) for elemental composition, and photoluminescence to track europium fluorescence. Synthesized nanotubes had inner diameters from 40 nm to 200 nm, based on the ZnO core. Following synthesis and characterization, the nanotubes will be tested for use as a drug delivery vector, using ibuprofen as a model.

Diffusiophoresis is the migration of a relatively large particle (e.g., protein, polymer, nanoparticle) induced by a gradient of salt concentration. The salt-induced diffusiophoresis of lysozyme, a model protein, at pH 4.5 and 25 °C was examined as a function of salt concentration for three chloride salts: NaCl, KCl and MgCl2. Diffusiophoresis coefficients were theoretically extracted from experimental multicomponent diffusion data by applying irreversible thermodynamics. A selected mass-transfer process was theoretically examined to show that concentration gradients of MgCl2 produce significant lysozyme diffusiophoresis. The dependence of lysozyme diffusiophoresis on salt nature was theoretically examined and linked to protein charge. The effect of salt type on hydrogen-ion titration curves was experimentally characterized to understand the role of salt nature on protein charge. Our findings indicate that diffusiophoresis may be exploited for diffusion-based separation of proteins in the presence of salt concentration gradients and for the enhancement of protein adsorption onto solid surfaces relevant to biosensing applications.

The randomization of 11 bases in the theophylline-binding domain generated a library containing millions of different theophylline riboswitch variants. The dual genetic selection of this molecular library successfully led to the identification of a caffeine-specific synthetic riboswitch. When a chloramphenicol-resistance gene was expressed under control of this caffeine riboswitch, E. coli cells showed chloramphenicol resistance only in the presence of caffeine. For a colorimetric or fluorescence assay, the caffeine riboswitch gene was inserted upstream of the B-galactosidase (LacZ) or green fluorescence protein (GFP) gene, respectively. When tested with various concentrations of caffeine, the enzymatic activity of LacZ or the fluorescence intensity of GFP was proportional to the amount of caffeine, clearly indicating the caffeine-dependent gene regulation by the caffeine riboswitch. The caffeine synthetic riboswitch can be further developed as a biosensor to detect caffeine in complex biological samples such as urine and blood.

Porous silicon (pSi) is a unique nanostructured form of the elemental semiconductor Si. Due to its useful properties governed by its surface chemistry and porous morphology, pSi has been studied in the last few decades in diverse fields extending from electronic device technology to bio-relevant applications.1 Recently, one-dimensional porous nanotubes based on elemental Si (pSiNTs) with a tunable structure (sidewalls, inner void space and lengths) have been successfully synthesized.2 The well-defined structure of pSiNTs offers ample opportunities to study newly emerging properties of this material and innovative applications in multiple areas. For example, recent reports have revealed the use of SiNTs as an efficient template for loading superparamagnetic nanoparticles (Fe3O4), lithium storage and cycling, as well as acting as a template for formation of organometal perovskite nanostructures.3-5
Platinum (Pt) nanoparticles, both free-standing as well as anchored on various surfaces, have attracted widespread attention in nanocatalysis, electronics, and chemotherapeutics.6 In this work, it is suggested that pSiNTs after being functionalized with 3-(aminopropyl)triethoxysilane (APTES) can serve as a platform for Pt nanocrystal (Pt NC) formation. Particularly, incubation of APTES-functionalized SiNTs in potassium tetrachloroplatinate (II) (K2PtCl4) solution under ambient conditions subsequently yields Pt nanoclusters with sizes ranging from 1-3 nm on SiNTs. From high-resolution transmission electron microscopy (HRTEM), nanocrystals with characteristic lattice spacings associated with Pt (d = 0.21 nm) are observed on the nanotubes. The amount of Pt deposited on SiNTs can be sensitively tuned from 20-60 wt% (characterized by TEM Energy Dispersive X-ray Analysis, EDX) by varying concentration of K2PtCl4 and immersion time in this Pt salt precursor.
These findings suggest a new approach to prepare Pt NCs that are of potential benefit to a broad number of applications by using pSiNTs as a template. Further investigations into the properties of the newly discovered Pt NCs-SiNT composites are imperative to evaluate useful applications of this material.
REFERENCES
[1] Porous Silicon for Biomedical Applications, H. Santos, Ed. Cambridge: Woodhead Publishing, 2014.
[2] X. Huang, R. Gonzalez-Rodriguez, R. Rich, Z. Gryczynski, J.L. Coffer, Chem. Commun., 2013, 49, 5760-5762.
[3] P. Granitzer, K. Rumpf, R. Gonzalez, J. Coffer, M. Reissner, Nanoscale Res. Lett. 2014, 9, 413.
[4] R. Gonzalez-Rodriguez, N. Arad-Vosk, N. Rozenfeld, A. Sa'ar, J. L. Coffer, Small, 2016, 12, 4477-4480.
[5] A. T. Tesfaye, R. Gonzalez, J. L. Coffer, T. Djenizian, ACS Appl. Mater. Interfaces, 2015, 7, 20495-20498.
[6] A. Chen, and P. Holt-Hindle, Chem. Rev., 2010, 110, 3767-3804.

Atomic partial charges obtained from computed wavefunctions are widely used for interpreting quantum chemistry simulations and chemical reactivities of molecules, solids, surfaces, and nanoparticles. In many cases, partial charge alone gives an incomplete picture of reactivity: PhS(-) is a better nucleophile compared to PhO(-) in SN2 reactions with MeI, though PhO(-) has a more negative charge on the nucleophilic atom, the carbons of benzene and cyclobutadiene, or those of diamond, graphene, and C60, possess nearly identical partial charges and very different reactivities, deprotonated amides perform nucleophilic attack via the less negative nitrogen, rather than the more negative oxygen, in anionic cyclization of o-alkynyl benzamides, halide anions F(-), Cl(-), Br(-) and I(-) have identical charges but different nucleophilicities, carbons in aromatic benzene and anti-aromatic cyclobutadiene have nearly identical partial charges, but different reactivities. Our atomic overlap distance complements computed partial charges by measuring the size of orbital lobes that best overlap with the wavefunction around an atom. Compact, chemically stable atoms tend to have overlap distances smaller than chemically soft, unstable atoms. Combining atomic charges and overlap distances captures trends in aromaticity, nucleophilicity, allotrope stability, and substituent effects. Applications to recent experiments in organic chemistry (counterintuitive Lewis base stabilization of alkenyl anions in anionic cyclization), nanomaterials chemistry (facile doping of the central atom in Au7 hexagons) and selective binding of ligands in proteins illustrate this combination’s predictive power.

Amaryllidaceae isoquinoline alkaloids, as well as their analogs, have long been of interest in research for drug discovery due to their biologically active nature. Many of these compounds have been found to be anti-tumor agents.1 Moreover, there have also been studies that show the effectiveness of these molecules against diseases such as Yellow Fever and other RNA-containing flaviviruses.2 Though these compounds are pharmaceutical drug prospects, their low natural abundance lowers that potential.3 For this reason, many synthetic chemists have pursued novel routes to synthesize a wide variety of these compounds.
Techniques toward the synthesis of Pancratistatin-type natural products are presented herein. Manipulations were tested and optimized on a model system to save both time and funds while developing a synthetic pathway to be utilized in the formation of more complex compounds. Setbacks such as controlling the stereochemistry of a tetrasubstituted alkene reduction have been encountered. However, adjustments are being made to avoid such difficulties. Ideally, the proposed scheme will ultimately allow for the synthesis of multiple biologically active Phenanthridone analogs.

Hippadine and pratosine are lycorine-type pharmacologically active Amaryllidaceae alkaloids. Various total syntheses of these natural products have been developed. However, most of these synthetic routes require prohibitively expensive materials and/or achieve yields that are subpar, making these schemes unlikely to be used in an industrial setting. Current research involves developing better synthetic methods for these two alkaloids starting with a 6,7-disubstituted isoquinoline. These syntheses are appealing since they utilize readily available starting materials and avoid expensive catalysts. The key step in the synthetic scheme centers around an intramolecular de Mayo photocyclization which involves a reaction between an alkene moiety in the isocarbostyril system and a 1,3-diketone (a functionalized tether on nitrogen), which forms a third ring in the structure of the molecule. When the photochemical reaction was attempted, an unexpected cyclic photoproduct was obtained; fortunately, this product is a cyclic hemiketal of the expected 1,5-dicarbonyl compound. A base-catalyzed aldol addition affords the final ring in the system; dehydration of this product affords a β-enone that can be transformed to a diene. Oxidation of the diene with DDQ affords the target natural products after simple chromatographic purification. This new synthetic pathway circumvents the need for catalysts that are either expensive or contain metals such as palladium or iridium; moreover, our method allows for the synthesis of various natural and unnatural alkaloids in high yields by modification of the N-tether.