Facile conversion of RNA aptamers to modular fluorescent sensors with tunable detection wavelengths.

A GTP aptamer was converted to a modular fluorescent GTP sensor by conjugation of RRE (Rev responsive element) RNA and successive complex formation with a fluorophore-modified Rev peptide. Structural changes associated with substrate binding in the RNA aptamer were successfully transduced into changes in fluorescence intensity because of the modular structure of ribonucleopeptides. A simple modular strategy involving conjugation of a fluorophore-modified ribonucleopeptide to the stem region of an RNA aptamer deduced from secondary structural information helps produce fluorescent sensors, which allow tuning of excitation and detection wavelengths through the replacement of the fluorophore at the N-terminal of the Rev peptide

Influence of polymer molecular weight on the properties of in situ synthesized silver–methylcellulose nanocomposite films with a CO₂ laser

We investigate the influence of polymer molecular weight on the properties of silver–methylcellulose (Ag–MC) nanocomposite films synthesized by the irradiation of a CO₂ laser. Although the reduction power of MC with a smaller molecular weight turns out to be stronger than that with a larger molecular weight in the solution phase, we do not see such a clear difference when MC is in the matrix phase. For the 30 s irradiation at the laser power of 0.8 W, the size of Ag nanoparticles (NPs) in the two types of MC matrix is similar, and it is about 30 nm. However, for the longer irradiation time at the same laser power, aggregation of Ag NPs set in, and it is more serious for the Ag–MC film with MC of larger molecular weight. We also carry out the antibacterial test with the Ag–MC films, and find that the Ag–MC film synthesized at the lower laser power and shorter irradiation time generally exhibits a stronger antibacterial effect

Overview of research on tuna thermo-physiology using electric tags

The behavioral physiology of bigeye tuna was investigated using acoustic tags in the 1990s. They spend most of the daylight hours below the thermocline but make regular brief excursions into the mixed layer. In doing so, they reduce the efficacy of their vascular countercurrent heat exchangers while gaining heat from the warmer environment and then increase it again when they return below the thermocline. Recently, archival tags have been used on a range of tuna species including bluefin. This tag, recovered when the tuna is harvested, yields time-series data over longer periods than acoustic tags. Although immature Pacific bluefin spend most of their time at the surface, they often dive below the thermocline, maintaining a peritoneal temperature. This might be due either to heat conservation or high heat production. Further, while giant Atlantic bluefin show an ability to maintain their temperature above the ambient, there are occasions in cold water when some physiological process is clearly limiting their dive time. Solution of the growth conundrum that their warm body temperature may pose an ecological problem as they grow in body mass, should be clarified by using tag data. This will lead to investigation of their adaptation mechanisms to their habitats