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Rx/rax (retinal homeobox) gene encodes a transcription factor with a paired-like homeodomain and is mainly expressed in neural retina. In mouse Rx/rax null embryos, the optic cup and eye are not formed. Overexpression of Rx in Xenopus embryos induced overgrowth of neural retina and pigmented epithelium. These results show that Rx/rax is involved in eye development, but its molecular mechanism underlying neural retina formation is still unclear. Chicken homolog of Rx/rax was cloned to study this issue by gene transfer into chicken embryos, cRaxL transcripts begins to be detected in anterior neural plate at stage 7 and then in neural retina at stage 16. At E8-18 embryo cRaxL expression become restricted to the inner nuclear and photoreceptor layer, but at E20 its expression is lost. To analyze cRaxL function, we introduced cRaxL-plasmids into stage 10-11 optic vesicles by the electroporation technique. Overexpression of cRaxL resulted in a loss of the optic stalks. In situ hybridization analysis demonstrated that cRaxL suppressed Pax-6 and Pax-2 expression, and gave no effect to Six3 and Vax1 expression, but BF-1 was ectopically expressed. Embryo transfected with a dominant-active cRaxL (VP16-cRaxL) showed the same phenotype as that of cRaxL, suggesting that cRaxL is a transcriptional activator. RCAS-cRaxL virus particles were injected into the optic vesicles at stage 10-11. In these infected E14 embryos, the number of ganglion cells was reduced and [Delta]-crystallin transcripts were not detected in lens-fiber cells. These results suggest that cRaxL is involved in ganglion cell differentiation and ganglion cells may produce a secreted factor(s) essential for lens-fiber differentiation.

In a preceding report (UCL Open: Environment, 2020;1;6), an example of results on changes in the acoustic environment from a local-scale survey in a quiet residential area during and after the ‘state of emergency’ due to COVID-19 pandemic in Japan is presented: the noise level was 1–2 dBA lower during the state of emergency, which is smaller than reported from large cities. This note presents the results of a follow-up survey in the same area to provide some more examples to gain an insight into the acoustic environment in this area. In this note, the measurement results of noise levels in June 2020, a few weeks after the cancellation of the state of emergency, are mainly reported. As the results are almost the same as those from during the state of emergency, we can infer that either the noise level was reduced in June to a level that was almost the same as that during the state of emergency, or the noise level after its cancellation in May was possibly higher than usual. In either case, the change in noise level was small, and it was difficult to conclude which case was true.