Probing antioxidant activity of 2′-hydroxychalcones: Crystal and molecular structures, in vitro antiproliferative studies and in vivo effects on glucose regulation

In order to better understand the antioxidant behavior of a series of polyphenolic 2′-hydroxychalcones, we describe the results of several chemical and biological studies, in vitro and in vivo. Single crystal X-ray methods elucidated their molecular structures and important intermolecular interactions such as H-bonding and molecular stacking in the crystal structures that contribute to our knowledge in explaining antioxidant activity. The results of experiments using the 1,1-diphenyl-2-dipicrylhydrazyl (DPPH) UV–vis spectroscopic method indicate that a hydroxyl group in position 5′ induces the highest antioxidant activity. Consequently, 2,2′,5′-trihydroxychalcone was selected for further study in vitro towards ROS scavenging in L-6 myoblasts and THP-1 human monocytes, where it shows an excellent antioxidant activity in a concentration range lower than that reported by most studies of related molecules. In addition, this chalcone shows a very selective activity: it inhibits the proliferation of leukemic cells, but it does not affect the normal L-6 myoblasts and human fibroblasts. In studying 2,2′,5′-trihydroxychalcone's effect on weight gain and serum glucose and insulin levels in Zucker fatty (fa⁻/fa⁻) rats we found that supplementing the diet with a 10 mg/kg dose of this chalcone (3 times weekly) blunted the increase in glucose that co-occurs with weight gain over the 6-week treatment period. It is concluded that 2,2′,5′-trihydroxychalcone has the potential to serve as a protective agent for some debilitating diseases.     

Two silicone nontoxic fouling release coatings: Hydrosilation cured PDMS and CaCO3 filled,ethoxysiloxane cured RTV11

Two silicone coatings have been evaluated for barnacle adhesion. One coating is an unfilled hydrosilation cured polydimethylsiloxane (PDMS) network, while the other is a room temperature vulcanized (RTV), filled, ethoxysiloxane cured PDMS elastomer, RTV11^?. The adhesion strength of one species of barnacle, Balanus eburneus, to the hydrosilation coatings is in the range of 0.37–0.60 kg cm^‐2 while the corresponding range for RTV11 is 0.64–0.90 kg cm^‐2. The easier release of B. eburneus from the hydrosilation cured network compared to RTV11 is discussed in relationship to differences in bulk and surface properties. Preliminary results suggest bulk modulus may be the most important parameter in determining barnacle adhesion strength. In light or mechanical property analysis, a re‐evaluation of surface properties and chemical stability is presented.     

Chemostat and in‐situ colonization kinetics of thermothrix thiopara on calcite and pyrite surfaces

Growth and attachment rates of Thermothrix thiopara on calcite and pyrite were quantitated in a thiosulfate‐limited chemostat and in the thermal spring where the organism is found in nature. Surface growth rates were quantitated by using the surface colonization and exponential growth equations. These two models were compared as means of determining surface growth rates. In the chemostat, T. thiopara cells colonizing calcite and pyrite surfaces grew at approximately one‐third the rate of suspended cells. However, T. thiopara attached to pyrite faster than to calcite. In the thermal spring, growth and attachment rates were equal on calcite and pyrite. It was concluded that the exponential growth equation overestimates in‐situ surface growth rates and that T. thiopara grows more slowly when colonizing mineral surfaces than when growing in suspension. Lower growth rates on surfaces may be due to a reduced cell surface area for nutrient uptake or an increased specific maintenance rate.     

Meeting reports

This investigation documents the formation of Green Rust (GR) and immobilization of Ni 2+ in response to bacterial reduction of hydrous ferric oxide (HFO). In the absence of Ni 2+ , 79% of the total Fe(III) present as HFO was reduced; at 10 -3 and 10 -4 M Ni 2+ , 36% of the total Fe(III) was reduced, whereas 45 to 50% of the total Fe(III) was reduced at 10 -5 M Ni 2+ . The inhibitory effect of 10 -3 and 10 -4 M Ni 2+ on Fe(III)-reduction corresponded to a 50% decrease in number of viable cells relative to the Ni 2+ -free condition, and a 25% decrease at 10 -5 M Ni 2+ . A prominent GR peak at d = 10.9 nm was evident in X-ray diffraction patterns of postreduction residual solids from the cultures. Minor peaks arising for vivianite and magnetite were also present. In samples prepared for scanning electron microscopy, thin hexagonal plates of GR were easily distinguished as a solid phase transformation product of HFO. Small hexagonal sheets and fragments of larger GR plates were also observed in transmission electron microscopy whole mounts together with bacteria that were mineralized by surface precipitates of microcrystalline magnetite. Energy dispersive spectroscopy (EDS) confirmed that GR contained Fe and P, as well as Ni in those samples taken from the Ni 2+ -amended experiments. EDS detected neither P nor Ni in the magnetite precipitates associated with the bacterial cells. Dissolved Ni2 + concentrations decreased in an exponential fashion with respect to time in all experimental systems, corresponding to an overall first-order rate constant k of -0.030 day -1 . At the same time, a strong linear relationship (r 2 = 0.99) between the dissolved and solid phase Ni 2+ /Fe 2+ ratios over the entire period of the Fe(III)reduction experiments provided evidence that the solid-phase partitioning of Ni 2+ in GR extended from equilibrium solid-solution behavior.     

Obligate Brood Parasites Show More Functionally Effective Innate Immune Responses: An Eco-immunological Hypothesis

Immune adaptations of obligate brood parasites attracted interest when three New World cowbird species (Passeriformes, Icteridae, genus Molothrus) proved unusually resistant to West Nile virus. We have used cowbirds as models to investigate the eco-immunological hypothesis that species in parasite-rich environments characteristically have enhanced immunity as a life history adaptation. As part of an ongoing program to understand the cowbird immune system, in this study we measured degranulation and oxidative burst, two fundamental responses of the innate immune system. Innate immunity provides non-specific, fast-acting defenses against a variety of invading pathogens, and we hypothesized that innate immunity experiences particularly strong selection in cowbirds, because their life history strategy exposes them to diverse novel and unpredictable parasites. We compared the relative effectiveness of degranulation and oxidative burst responses in two cowbird species and one related, non-parasitic species. Both innate immune defenses were significantly more functionally efficient in the two parasitic cowbird species than in the non-parasitic red-winged blackbird (Icteridae, Agelaius phoeniceus). Additionally, both immune defenses were more functionally efficient in the brown-headed cowbird (M. ater), an extreme host-generalist brood parasite, than in the bronzed cowbird (M. aeneus), a moderate host-specialist with lower exposure to other species and their parasites. Thus the relative effectiveness of these two innate immune responses corresponds to the diversity of parasites in the niche of each species and to their relative resistance to WNV. This study is the first use of these two specialized assays in a comparative immunology study of wild avian species.     

The Taste of Nationalism: Food Politics in Postsocialist Moscow

In this article I consider how Muscovites cultivate and express nationalist sentiments through their food choices. During the last ten years of the post-socialist transition, Russian consumers have encountered an expanding and increasingly transnational commodity market. Locally produced elements of Russian cuisine both compete with and imitate foreign food products. In response to perceptions that foreign cultures are displacing or subsuming local cultural forms, Russian officials have launched a 'Buy Russian' campaign. Domestic food producers, store clerks, and customers collaborate to classify foods and other products as either 'Ours'(Nash) or 'Not Ours' (Ne nash) and describe local goods as superior to foreign goods in terms of taste, quality, and healthfulness. In their own narratives about consumption choices, Muscovites echo these nationalist themes by explicitly linking their personal food experiences with broader political issues. Drawing from ethnographic fieldwork on foodpractices in Moscow(1995-2001), I suggest that consumption strategies mediate Muscovites' experiences with growing nationalist sentiments in the context of a globalizing Russia.     

Synthesis and evaluation of heteroaryl substituted diazaspirocycles as scaffolds to probe the ATP-binding site of protein kinases

With the success of protein kinase inhibitors as drugs to target cancer, there is a continued need for new kinase inhibitor scaffolds. We have investigated the synthesis and kinase inhibition of new heteroaryl-substituted diazaspirocyclic compounds that mimic ATP. Versatile syntheses of substituted diazaspirocycles through ring-closing metathesis were demonstrated. Diazaspirocycles directly linked to heteroaromatic hinge binder groups provided ligand efficient inhibitors of multiple kinases, suitable as starting points for further optimization. The binding modes of representative diazaspirocyclic motifs were confirmed by protein crystallography. Selectivity profiles were influenced by the hinge binder group and the interactions of basic nitrogen atoms in the scaffold with acidic side-chains of residues in the ATP pocket. The introduction of more complex substitution to the diazaspirocycles increased potency and varied the selectivity profiles of these initial hits through engagement of the P-loop and changes to the spirocycle conformation, demonstrating the potential of these core scaffolds for future application to kinase inhibitor discovery.     

Geographic distribution of genetic diversity in populations of Rio Grande Chub <Emphasis Type="Italic">Gila pandora</Emphasis>

In the southwestern United States (US), the Rio Grande chub (Gila pandora) is state-listed as a fish species of greatest conservation need and federally listed as sensitive due to habitat alterations and competition with non-native fishes. Characterizing genetic diversity, genetic population structure, and effective number of breeders will assist with conservation efforts by providing a baseline of genetic metrics. Genetic relatedness within and among G. pandora populations throughout New Mexico was characterized using 11 microsatellite loci among 15 populations in three drainage basins (Rio Grande, Pecos, Canadian). Observed heterozygosity (H_O) ranged from 0.71–0.87 and was similar to expected heterozygosity (0.75–0.87). Rio Ojo Caliente (Rio Grande) had the highest allelic richness (A_R = 15.09), while Upper Rio Bonito (Pecos) had the lowest allelic richness (A_R = 6.75). Genetic differentiation existed among all populations with the lowest genetic variation occurring within the Pecos drainage. STRUCTURE analysis revealed seven genetic clusters. Populations of G. pandora within the upper Rio Grande drainage (Rio Ojo Caliente, Rio Vallecitos, Rio Pueblo de Taos) had high levels of admixture with Q-values ranging from 0.30–0.50. In contrast, populations within the Pecos drainage (Pecos River and Upper Rio Bonito) had low levels of admixture (Q = 0.94 and 0.87, respectively). Estimates of effective number of breeders (N _b ) varied from 6.1 (Pecos: Upper Rio Bonito) to 109.7 (Rio Grande: Rio Peñasco) indicating that populations in the Pecos drainage are at risk of extirpation. In the event that management actions are deemed necessary to preserve or increase genetic diversity of G. pandora, consideration must be given as to which populations are selected for translocation.     

A multi‐basin approach determines variability in host fish suitability for unionids in tributaries of the Laurentian Great Lakes

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