A hierarchical Bayesian model to estimate the unobservable predation rate on sawfly cocoons by small mammals.

Predation by small mammals has been reported as an important mortality factor for the cocoons of sawfly species. However, it is difficult to provide an accurate estimate of newly spun cocoons and subsequent predation rates by small mammals for several reasons. First, all larvae do not spin cocoons at the same time. Second, cocoons are exposed to small mammal predation immediately after being spun. Third, the cocoons of the current generation are indistinguishable from those of the previous generation. We developed a hierarchical Bayesian model to estimate these values from annual one-time soil sampling datasets. To apply this model to an actual data set, field surveys were conducted in eight stands of larch plantations in central Hokkaido (Japan) from 2009 to 2012. Ten 0.04-m(2) soil samples were annually collected from each site in mid-October. The abundance of unopened cocoons (I), cocoons emptied by small-mammal predation (M), and empty cocoons caused by something other than small-mammal predation (H) were determined. The abundance of newly spun cocoons, the predation rate by small mammals before and after cocoon sampling, and the annual rate of empty cocoons that remained were estimated. A posterior predictive check yielded Bayesian P-values of 0.54, 0.48, and 0.07 for I, M, and H, respectively. Estimated predation rates showed a significant positive correlation with the number of trap captures of small mammals. Estimates of the number of newly spun cocoons had a significant positive correlation with defoliation intensity. These results indicate that our model showed an acceptable fit, with reasonable estimates. Our model is expected to be widely applicable to all hymenopteran and lepidopteran insects that spin cocoons in soil.

Long-acting genipin derivative protects retinal ganglion cells from oxidative stress models in vitro and in vivo through the Nrf2/antioxidant response element signaling pathway.

Previously, we reported that genipin, a herbal iridoid, had neuritogenic and neuroprotective actions on PC12 cells. Although nitric oxide (NO)-activated signalings were proposed to be neuritogenic, the neuroprotective action of genipin remains to be elucidated. From the standpoint of NO activation, we tested a possible protective mechanism through the nitrosative Kelch-like ECH-associated protein (Keap1)/NF-E2-related factor 2 (Nrf2)-antioxidant response element pathway in rat retinal ganglion cells (RGC-5 cells) in culture, and in vivo, against hydrogen peroxide and optic nerve injury (ONI), respectively, using a long-acting (1R)-isoPropyloxygenipin (IPRG001). IPRG001 induced NO generation and the expressions of antioxidative enzymes, such as heme oxygenase-1 (HO-1), in RGC-5 cells. The protective action of IPRG001 depended on HO-1 and NO induction. We found that S-nitrosylation of Keap1 by IPRG001 may contribute to translocation of Nrf2 to the nucleus and triggered transcriptional activation of antioxidative enzymes. Furthermore, apoptotic cells were increased and 4-hydroxy-2-nonenal was accumulated in rat retina following ONI. Pre-treatment with IPRG001 almost completely suppressed apoptosis and accumulation of 4-hydroxy-2-nonenal in RGCs following ONI accompanied by HO-1 induction. These data demonstrate for the first time that IPRG001 exerts neuroprotective action in RGCs in vitro and in vivo, through the Nrf2/antioxidant response element pathway by S-nitrosylation against oxidative stress.

Wideband digital frequency detector with subtraction-based phase comparator for frequency modulation atomic force microscopy.

We have developed a wideband digital frequency detector for high-speed frequency modulation atomic force microscopy (FM-AFM). We used a subtraction-based phase comparator (PC) in a phase-locked loop circuit instead of a commonly used multiplication-based PC, which has enhanced the detection bandwidth to 100 kHz. The quantitative analysis of the noise performance revealed that the internal noise from the developed detector is small enough to provide the theoretically limited noise performance in FM-AFM experiments in liquid. FM-AFM imaging of mica in liquid was performed with the developed detector, showing its stability and applicability to true atomic-resolution imaging in liquid.

Purpurin is a key molecule for cell differentiation during the early development of zebrafish retina.

Recently, we cloned purpurin cDNA as an upregulated gene in the axotomized fish retina. The retina-specific protein was secreted from photoreceptors to ganglion cell layer during an early stage of optic nerve regeneration in zebrafish retina. The purpurin worked as a trigger molecule for axonal regrowth in adult injured fish retina. During zebrafish development, purpurin mRNA first appeared in ventral retina at 2 days post-fertilization (dpf) and spread out to the outer nuclear layer at 3 dpf. Here, we investigated the role of purpurin for zebrafish retinal development using morpholino gene knockdown technique. Injection of purpurin morpholino into the 1-2 cell stage of embryos significantly inhibited the transcriptional and translational expression of purpurin at 3 dpf. In the purpurin morphant, the eyeball was significantly smaller and retinal lamination of nuclear and plexiform layers was not formed at 3 dpf. Retinal cells of purpurin morphants were still proliferative and undifferentiated at 3 dpf. The visual function of purpurin morphant estimated by optomotor response was also suppressed at 5 dpf. By contrast, the control morphants with random sequence morpholino showed retinal lamination with distinct layers and differentiated cells at 3 dpf. These results strongly suggest that purpurin is a key molecule for not only optic nerve regeneration in adult but also cell differentiation during early development in embryo.

A comprehensive analysis of allelic methylation status of CpG islands on human chromosome 11q: comparison with chromosome 21q.

It was generally believed that autosomal CpG islands (CGIs) escape methylation. However, our comprehensive analysis of allelic methylation status of 149 CGIs on human chromosome 21q revealed that a sizable fraction of them are methylated on both alleles even in normal blood cells. Here, we performed a similar analysis of 656 CGIs on chromosome 11q, which is gene-rich in contrast with 21q. The results indicate that 11q contains less methylated CGIs, especially those with tandem repeats and those in the coding or 3'-untranslated regions (UTRs), than 21q. Thus, methylation status of CGIs may substantially differ from one chromosome to another.