Effective population sizes of eastern oyster Crassostrea virginica (Gmelin) populations in Delaware Bay, USA

Effective population size (Ne) is an important concept in population genetics as it dictates the rate of genetic change caused by drift. Ne estimates for many marine populations are small relative to the census population size. Small Ne in a large population may indicate high reproductive variance or sweepstakes reproductive success (SRS). The eastern oyster (Crassostrea virginica) may be prone to SRS due to its high fecundity and high larval mortality. To examine if SRS occurs in the eastern oyster, we studied Ne and genetic variation of oyster populations in Delaware Bay. Adult and spat oysters were collected from five locations in different years and genotyped with seven microsatellite markers. Slight genetic differences were revealed by Fst statistics between the adult populations and spat recruits, while the adult populations are spatially homogeneous and temporally stable. Comparisons of genetic diversity and relatedness among adult and spat samples failed to provide convincing evidence for strong SRS. Ne estimates obtained with five different methods were variable, small and often without upper confidence limits. For single sample collections, Ne estimates for spat (140–440) were consistently smaller than that for adults (589–2,779). Analysis of pooled adult samples across all sites suggests that Ne for the whole bay may be very large, as indicated by the large point estimates and the lack of upper confidence limits. These results suggest that Ne may be small for a given spat fall, but the entire adult population may have large Ne and is temporally stable as it is the accumulation of many spat falls per year over many year

N-Benzyl-2-(2-chloro-4-methyl­phen­oxy)acetamide

The structure determination of the title compound, C16H16ClNO2, was performed as part of a project on the inter­actions between small organic mol­ecules and proteins. In the crystal structure, the dihedral angle between the two aromatic rings is 16.14 (12)°. The molecules are connected via N—H⋯O hydrogen bonding into chains, which extend in the direction of the b axis

Influence of Reducing Agents on Biosafety and Biocompatibility of Gold Nanoparticles

Extensive biomedical applications of nanoparticles are mainly determined by their safety and compatibility in biological systems. The aim of this study was to compare the biosafety and biocompatibility of gold nanoparticles (GNPs) prepared with HEPES buffer, which is popular for cell culture, and sodium citrate, a frequent reducing agent. From experimental results on the body weight and organ coefficients of acute oral toxicity tests, it could be observed that HEPES-prepared GNPs are biologically safer than citric-prepared GNPs at the same dose of 500 μg/kg. The in vitro cell viability was higher for HEPES-prepared GNPs than citric-prepared GNPs at 5.0- and 10.0-ug/mL concentrations. More reactive oxygen species (ROS) were generated in the cell suspension when supplemented with citric-prepared GNPs than HEPES-prepared GNPs when their concentrations were higher than 20 μg/mL. The results stated that HEPES-prepared GNPs had better biosafety and biocompatibility than citric-prepared GNPs. This study not only revealed the influence of reducing agent on biosafety and biocompatibility of nanomaterials but also provided accumulative evidence for nanomaterials in biomedical applications. [Figure: see text