No abstract

Recombinant "all-fish" growth hormone gene (GH) was microinjected into the fertilized eggs of carp. A comparison between the growth traits of transgenics and non-transgenics was carried out, and the transgenic individuals with significant "fast-growing" effect were successfully gained. A comparison on the reproductivities was also given out between the transgenics and their non-transgenic siblings, and showed that the reproductive capacity of transgenics was substantially equivalent to those of the non-transgenics. On the other hand, the genetic separation and the characteristic distribution of the F 1 generation were genetically analyzed, which gave solid evidence for the hypothesis that 2 3 chromosomes are integrated with transgene. In addition, the distinct biological effects for multi-siteintegrated transgenes were further discussed. The present study opens a door for the breeding of "fast-growing" transgenic fish.

We describe the synthesis of mixed, or binary, polymer brushes containing polystyrene (PS) and poly(methyl methacrylate) (PMMA). These films were synthesized by a grafting-from (GF) strategy from gold substrates that were coated with a bis-thiol free radical photoinitiator, similar to 2,2‘-azobis(isobutyronitrile) (AIBN). The PS layer was 70 nm thick for all substrates, and the PMMA was varied up to 700 nm. The number-average molecular weight (M n) of the ungrafted polymers was determined by gel permeation chromatography (GPC) and multiangle light scattering (MALS); the M n for bulk PS and PMMA was ∼57 000 and ∼515 000 Da, respectively. The air/liquid interface was probed by static water contact angles (θ) and X-ray photoelectron spectroscopy (XPS). We found that both θ and the oxygen concentration varied depending on whether the substrate was immersed in a nonselective solvent (tetrahydrofuran) or selective solvent for PS (cyclohexane) or PMMA (isobutanol). The morphology was monitored by atomic force microscopy (AFM), and we observed a dimple-type structure in cyclohexane and isobutanol, with less nanophase separation after immersion in tetrahydrofuran. Reflection−absorption infrared spectroscopy (RAIRS) was used to quantify the % PMMA in the binary brushes, which ranged from 0 to 90%, and was confirmed by XPS. These substrates exhibited reversible switching, and both lateral and layered nanophase separation were observed. The elasticity of a mixed brush was probed by AFM and was found to lie between that of neat PS and PMMA.

We present a simple “top-down/bottom-up” strategy to fabricate nano- and micropatterned polymer brush arrays composed of pH- and salt-sensitive, weak polyelectrolyte copolymers [poly(N-isopropylacrylamide-co-methacrylic acid, 3:1, poly(NIPAAM-co-MAA)]. In our approach, a silicon surface is first patterned with gold, using “lift-off” electron-beam lithography (“top-down”), and the resulting pattern is then amplified by surface-initiated photopolymerization by conventional, UV-light-induced free radical polymerization (“bottom-up”) from an immobilized 2,2‘-azobisisobutyronitrile (AIBN) type initiator. The use of pH- and ionic-strength-sensitive comonomers in the copolymer brush enables large, externally triggered conformational changes of the micro- and nanopatterned polymer brushes. We observed that the height of nanopatterned ionized polymer brushes increases with increasing feature size of the pattern. The design and fabrication of surfaces with conformationally switchable, patterned polymeric structures is important for sensing and actuation applications on the micro- and nanoscales.