OAZ-t/OAZ3 Is Essential for Rigid Connection of Sperm Tails to Heads in Mouse

Polyamines are known to play important roles in the proliferation and differentiation of many types of cells. Although considerable amounts of polyamines are synthesized and stored in the testes, their roles remain unknown. Ornithine decarboxylase antizymes (OAZs) control the intracellular concentration of polyamines in a feedback manner. OAZ1 and OAZ2 are expressed ubiquitously, whereas OAZ-t/OAZ3 is expressed specifically in germline cells during spermiogenesis. OAZ-t reportedly binds to ornithine decarboxylase (ODC) and inactivates ODC activity. In a prior study, polyamines were capable of inducing a frameshift at the frameshift sequence of OAZ-t mRNA, resulting in the translation of OAZ-t. To investigate the physiological role of OAZ-t, we generated OAZ-t–disrupted mutant mice. Homozygous OAZ-t mutant males were infertile, although the polyamine concentrations of epididymides and testes were normal in these mice, and females were fertile. Sperm were successfully recovered from the epididymides of the mutant mice, but the heads and tails of the sperm cells were easily separated in culture medium during incubation. Results indicated that OAZ-t is essential for the formation of a rigid junction between the head and tail during spermatogenesis. The detached tails and heads were alive, and most of the headless tails showed straight forward movement. Although the tailless sperm failed to acrosome-react, the heads were capable of fertilizing eggs via intracytoplasmic sperm injection. OAZ-t likely plays a key role in haploid germ cell differentiation via the local concentration of polyamines

Effects of Niko Niko Room's educational support on school children (4) : Survey results of school children and their parents who participated in the programs between the first semester of 2008 and the second semester of 2009

The purpose of this study was to examine the effects of an educational support program on school children who participated in the programs held between the first semester of 2008 and the second semester of 2009. The educational support program was held at the Niko Niko Room which is a clinic of school psychology at the Center for School Education and Research of Hiroshima University. Data of 57 school children who answered questionnaires before and after the program, and their 57 guardians who answered questionnaires only after the program were used for the analysis. Results showed that the educational support program had a positive effect on the children's "self-efficacy regarding arithmetic". Both children and their guardians highly evaluated the students' abilities who gave actual support to the children. Also, when the students' abilities are highly perceived, children's "interests in arithmetic‘" were also highly perceived. Overall, the effects of the educational support program were positively evaluated by both the children and their guardians