Nuclear Transformation of the Marine Pennate Diatom Nitzschia sp. Strain NIES-4635 by Multi-Pulse Electroporation.

Nitzschia is one of the largest genera of diatoms found in a range of aquatic environments, from freshwater to seawater. This genus contains evolutionarily and ecologically unique species, such as those that have lost photosynthetic capacity or those that live symbiotically in dinoflagellates. Several Nitzschia species have been used as indicators of water pollution. Recently, Nitzschia species have attracted considerable attention in the field of biotechnology. In this study, a transformation method for the marine pennate diatom Nitzschia sp. strain NIES-4635, isolated from the coastal Seto Inland Sea, was established. Plasmids containing the promoter/terminator of the fucoxanthin chlorophyll a/c binding protein gene (fcp, or Lhcf) derived from Nitzschia palea were constructed and introduced into cells by multi-pulse electroporation, resulting in 500 µg/mL nourseothricin-resistant transformants with transformation frequencies of up to 365 colonies per 108 cells. In addition, when transformation was performed using a new plasmid containing a promoter derived from a diatom-infecting virus upstream of the green fluorescent protein gene (gfp), 44% of the nourseothricin-resistant clones exhibited GFP fluorescence. The integration of the genes introduced into the genomes of the transformants was confirmed by Southern blotting. The Nitzschia transformation method established in this study will enable the transformation this species, thus allowing the functional analysis of genes from the genus Nitzschia, which are important species for environmental and biotechnological development.

Gap Effect on Electric Field Enhancement and Photothermal Conversion in Gold Nanostructures.

Plasmonic optical tweezers and thermophoresis are promising tools for nanomaterial manipulation. When a gold nanostructure is irradiated with laser light, an electric field around the nanostructure is enhanced because of the localized surface plasmon resonance, which increases the optical radiation pressure applied to the nanomaterials. In addition, a temperature gradient is also generated by the photothermal conversion, and thermophoretic force is then generated. This study numerically evaluated the electric and temperature fields induced by the localized surface plasmon resonance between two gold nanostructures. Here, we focused on the effect of the gap width between nanostructures on the optical radiation pressure and thermophoretic force. The simulation results show that the electric field is locally enhanced according to the gap width, but the effect on the temperature rise due to the photothermal heating is small. This fact suggests that the gap effect between the nanostructures is particularly dominant in nanomanipulation using optical force, whereas it has little effect in nanomanipulation using thermophoresis.

Contralaterally controlled functional electrical stimulation immediately improves hand function.

Murata S, Koike Y, Kasukawa Y, Saito K, Okada K, Kudo D, Shimada Y, Miyakoshi N. Contralaterally controlled functional electrical stimulation immediately improves hand function. Jpn J Compr Rehabil Sci 2022; 13: 26-30. Objective: The purpose of this study was to investigate the immediate effects of contralaterally controlled functional electrical stimulation (CCFES) on upper limb function in stroke patients. Methods: CCFES and mirror therapy (MT) exercises were conducted for 13 stroke patients at least 4 weeks post-onset. A sufficient interval of at least 24 hours was left between the two types of rehabilitation exercises. Before treatment and immediately after each training session, grip strength, Fugl-Meyer Assessment for Upper Extremity (FMA-UE) score and FMA-UE subscores for the shoulder/elbow/forearm, wrist, hand, and coordination were evaluated. Results: Grip strength, FMA-UE and FMA-UE shoulder/elbow/forearm, wrist, and coordination did not differ significantly after CCFES and MT compared to before therapy. FMA-UE hand did not change significantly after MT compared to before therapy, but it improved significantly after CCFES (p = 0.013). Conclusion: CCFES for the upper extremities immediately improves hand function and may be effective in maintaining and improving patients' motivation for rehabilitation treatment.