Real-time time-division color electroholography using a single GPU and a USB module for synchronizing reference light.

We propose real-time time-division color electroholography using a single graphics processing unit (GPU) and a simple synchronization system of reference light. To facilitate real-time time-division color electroholography, we developed a light emitting diode (LED) controller with a universal serial bus (USB) module and the drive circuit for reference light. A one-chip RGB LED connected to a personal computer via an LED controller was used as the reference light. A single GPU calculates three computer-generated holograms (CGHs) suitable for red, green, and blue colors in each frame of a three-dimensional (3D) movie. After CGH calculation using a single GPU, the CPU can synchronize the CGH display with the color switching of the one-chip RGB LED via the LED controller. Consequently, we succeeded in real-time time-division color electroholography for a 3D object consisting of around 1000 points per color when an NVIDIA GeForce GTX TITAN was used as the GPU. Furthermore, we implemented the proposed method in various GPUs. The experimental results showed that the proposed method was effective for various GPUs.

Binding of Drosophila maternal Mamo protein to chromatin and specific DNA sequences.

Alterations in chromatin structure dynamically occur during germline development in Drosophila and are essential for the production of functional gametes. We had previously reported that the maternal factor Mamo, which contains both a BTB/POZ domain and C2H2 zinc-finger domains and is enriched in primordial germ cells (PGCs), is required for the regulation of meiotic chromatin structure and the production of functional gametes. However, the molecular mechanisms by which Mamo regulates germline development remained unclear. To evaluate the molecular function of Mamo protein, we have investigated the binding of Mamo to chromatin and DNA sequences. Our data show that Mamo binds to chromatin and specific DNA sequences, particularly the polytene chromosomes of salivary gland cells. Overexpression of Mamo affected the organization of polytene chromosomes. Reduction in maternal Mamo levels impaired the formation of germline-specific chromatin structures in PGCs. Furthermore, we found that the zinc-finger domains of Mamo directly bind to specific DNA sequences. Our results suggest that Mamo plays a role in regulating chromatin structure in PGCs.

Cyclical changes of plasma sex steroids in captive breeding loggerhead turtles (Caretta caretta).

Loggerhead turtles (Caretta caretta) have been laying eggs in an indoor artificial beach since 1995, at the Port of Nagoya Public Aquarium (PNPA). Four individuals landed and laid eggs several times during the breeding period in 1996. Blood samples from these individuals were collected monthly throughout that year in order to investigate the changes in sex steroid hormones (testosterone, estradiol, and progesterone). In addition, detailed investigations were conducted daily during the breeding period on one particular individual that landed and laid eggs five times in 1998. Each steroid hormone changed periodically based on the laying cycle, and extraordinarily high levels of estradiol were noted even during the breeding period. In reports regarding the green turtle (Chelonia mydas), extremely different results were observed. Some of the obtained data suggest that progesterone induced ovulation. Data from a completely artificial environment such as the one at the PNPA provides elucidation of the reproductive physiology in these endangered species.

A truncated form of a transcription factor Mamo activates vasa in Drosophila embryos.

Expression of the vasa gene is associated with germline establishment. Therefore, identification of vasa activator(s) should provide insights into germline development. However, the genes sufficient for vasa activation remain unknown. Previously, we showed that the BTB/POZ-Zn-finger protein Mamo is necessary for vasa expression in Drosophila. Here, we show that the truncated Mamo lacking the BTB/POZ domain (MamoAF) is a potent vasa activator. Overexpression of MamoAF was sufficient to induce vasa expression in both primordial germ cells and brain. Indeed, Mamo mRNA encoding a truncated Mamo isoform, which is similar to MamoAF, was predominantly expressed in primordial germ cells. The results of our genetic and biochemical studies showed that MamoAF, together with CBP, epigenetically activates vasa expression. Furthermore, MamoAF and the germline transcriptional activator OvoB exhibited synergy in activating vasa transcription. We propose that a Mamo-mediated network of epigenetic and transcriptional regulators activates vasa expression.