Transport properties of simple organic molecules in a transmembrane cyclic peptide nanotube.

Multiple molecular dynamics simulations have been performed to explore the transport properties of single methane, methanol, and ethanol molecules through the water-filled transmembrane cyclic peptide nanotube (CPNT) of 8 × (WL)4-POPE, as well as the potential application of this CPNT in the separation of an alcohol/water mixture. Molecular size and hydrophilicity/hydrophobicity were found to significantly influence molecular diffusion behavior in the channel. Methane and ethanol display more explicit distributions in midplane regions, while methanol mainly occurs in α-plane zones. Methane and ethanol drift faster near an α-plane zone, whereas methanol diffuses uniformly throughout the whole transmembrane region. The dipole orientation of channel methanol is significantly affected by the bare carbonyl groups at the tube mouths and flips mainly in gap 4, whereas the rotation of ethanol is blocked. Ball-shaped hydrophobic methane experiences more flips in gap 4. The PMF (potential of mean force) profiles of the three organic molecules disclose their different diffusion behaviors in the CPNT. Amphiphilic alcohols are able to form direct H-bonds with channel water and the tube. Both single and double water bridges with the tube were observed in the methanol and ethanol systems. The different adsorption behaviors of the alcohols and water in the dehydrated CPNT may lead to the potential application of the CPNT as a means of separating alcohols from water.

Development of inhibition of return for eye gaze in adolescents.

Gaze is an important cue in social interaction. Gaze direction can attract attention and produce a cuing effect as well as cause inhibition of return (IOR)--a slower response to an item at a previously attended-to location. Because gaze cue is sensitive to an individual's social interaction ability and such ability matures in adolescents, we examined how social attention by gaze cue varies with age. Three typically developing groups-ages 6 to 8, 9 to 12, and 13 to 15 years--were recruited. Each age group had 27 participants. Three main findings were observed. First, younger participants generated greater cuing effects than older ones. Second, reliable gaze-induced IOR was observed only in the 9- to 12-year and 13- to 15--year age groups, whereas the 6- to 8-year age group paid attention to gaze direction regardless of cue duration. Third, the 13- to 15-year age group showed gaze-induced IOR earlier (1200 ms) in the time course than expected (2400 ms). Our results suggest that the inhibition mechanism develops later than the facilitation mechanism in social attention.

Molecular cloning, characterization and expression analysis of grass carp (Ctenopharyngodon idellus) NF45 (ILF2) cDNA, a subunit of the nuclear factor of activated T-cells (NF-AT).

NF45 (ILF2) and NF90 (ILF3) regulate the IL-2 gene transcription via interaction with the antigen receptor response element. Much work on NF45 has been done in human and mammals while little in fish. In the present study, we have cloned and characterized the full-length cDNA of NF45 in grass carp (Ctenopharyngodon idellus). The grass carp NF45 cDNA of 1563bp contains a short 5'UTR of 24bp, a 3'UTR of 375bp and an open reading frame of 1164bp coding for a protein of 387 aa with a predicted molecular mass of 42.8kDa. The encoded protein shares 86.3-96.7% identities to other homologues. RT-PCR was optimized to estimate the expression level of NF45 in grass carp. The results showed that NF45 is constitutively expressed in most selected tissues, including head kidney, spleen, heart, brain, liver, and gill, although low levels were observed in spleen, liver and gill. The ubiquitous expression of NF45 is consistent with a postulated role in gene regulation at the level of transcription. Stimulating the fish with PHA significantly up-regulated the expression of NF45 in most tissues examined, which potentially indicated that NF45 was involved in the immune responses triggered by PHA.