小笠原諸島におけるムニンカケザトウムシの形態学的および遺伝学的研究

To clarify the morphological and phylogenetic differentiation of Bandona boninensis Suzuki 1974 in Chichi-jima Island of the Bonin (Ogasawara) group of Islands, we studied the external morphological characters and performed sequencing of the cytochrome c oxidase subunit I (COI) gene of mitochondrial DNA (mtDNA) and 28S rRNA of nuclear DNA (nrDNA). The sequences of COI and 28S rRNA were identical among the individuals of B. boninensis. These results suggest that B. boninensis experienced a rapid expansion of its distribution in Chichi-jima Island without undergoing any morphological and molecular differentiation.著者らは小笠原諸島の父島に生息するムニンカケザトウムシBandona boninensis の形態的および系統的分化を明らかにするために、父島の4 地点から採集を行い、体長、触肢腿節の長さ、背甲長および背甲幅、鋏角長、第1～4 脚の腿節長といった形態計測を実施し、ミトコンドリアDNA のCOI 領域および核DNA の28SrRNA 領域に基づく系統樹を作成した。その結果, ムニンカケザトウムシのCOI および28S において塩基置換は見られなかった。この結果は、ムニンカケザトウムシが父島内で系統的分化をほぼ起こしていないことを示す。また、採集を行った個体がすべて雌個体であったことから、これまでの報告の通り、父島においては単為生殖種として生息している可能性が高い

A series of ENU-induced single-base substitutions in a long-range cis-element altering Sonic hedgehog expression in the developing mouse limb bud

AbstractMammal–fish-conserved-sequence 1 (MFCS1) is a highly conserved sequence that acts as a limb-specific cis-acting regulator of Sonic hedgehog (Shh) expression, residing 1 Mb away from the Shh coding sequence in mouse. Using gene-driven screening of an ENU-mutagenized mouse archive, we obtained mice with three new point mutations in MFCS1: M101116, M101117, and M101192. Phenotype analysis revealed that M101116 mice exhibit preaxial polydactyly and ectopic Shh expression at the anterior margin of the limb buds like a previously identified mutant, M100081. In contrast, M101117 and M101192 show no marked abnormalities in limb morphology. Furthermore, transgenic analysis revealed that the M101116 and M100081 sequences drive ectopic reporter gene expression at the anterior margin of the limb bud, in addition to the normal posterior expression. Such ectopic expression was not observed in the embryos carrying a reporter transgene driven by M101117. These results suggest that M101116 and M100081 affect the negative regulatory activity of MFCS1, which suppresses anterior Shh expression in developing limb buds. Thus, this study shows that gene-driven screening for ENU-induced mutations is an effective approach for exploring the function of conserved, noncoding sequences and potential cis-regulatory elements

Association between enterocyte injury and fluid balance in patients with septic shock: a post hoc exploratory analysis of a prospective observational study

Background: The required fluid volume differs among patients with septic shock. Enterocyte injury caused by shock may increase the need for fluid by triggering a systematic inflammatory response or an ischemia-reperfusion injury in the presence of intestinal ischemia/necrosis. This study aimed to evaluate the association between enterocyte injury and positive fluid balance in patients with septic shock.Methods: This study was a post hoc exploratory analysis of a prospective observational study that assessed the association between serum intestinal fatty acid-binding protein, a biomarker of enterocyte injury, and mortality in patients with septic shock. Intestinal fatty acid-binding protein levels were recorded on intensive care unit admission, and fluid balance was monitored from intensive care unit admission to Day 7. The association between intestinal fatty acid-binding protein levels at admission and the infusion balance during the early period after intensive care unit admission was evaluated. Multiple linear regression analysis, with adjustments for severity score and renal function, was performed.Results: Overall, data of 57 patients were analyzed. Logarithmically transformed intestinal fatty acid-binding protein levels were significantly associated with cumulative fluid balance per body weight at 24 and 72 h post-intensive care unit admission both before (Pearson’s r = 0.490 [95% confidence interval: 0.263–0.666]; P < 0.001 and r = 0.479 [95% confidence interval: 0.240–0.664]; P < 0.001, respectively) and after (estimate, 14.4 [95% confidence interval: 4.1–24.7]; P = 0.007 and estimate, 26.9 [95% confidence interval: 11.0–42.7]; P = 0.001, respectively) adjusting for severity score and renal function.Conclusions: Enterocyte injury was significantly associated with cumulative fluid balance at 24 and 72 h post-intensive care unit admission. Enterocyte injury in patients with septic shock may be related to excessive fluid accumulation during the early period after intensive care unit admissio

Two distinct modes of DNMT1 recruitment ensure stable maintenance DNA methylation

Stable inheritance of DNA methylation is critical for maintaining differentiated phenotypes in multicellular organisms. We have recently identified dual mono-ubiquitylation of histone H3 (H3Ub2) by UHRF1 as an essential mechanism to recruit DNMT1 to chromatin. Here, we show that PCNA-associated factor 15 (PAF15) undergoes UHRF1-dependent dual mono-ubiquitylation (PAF15Ub2) on chromatin in a DNA replication-coupled manner. This event will, in turn, recruit DNMT1. During early S-phase, UHRF1 preferentially ubiquitylates PAF15, whereas H3Ub2 predominates during late S-phase. H3Ub2 is enhanced under PAF15 compromised conditions, suggesting that H3Ub2 serves as a backup for PAF15Ub2. In mouse ES cells, loss of PAF15Ub2 results in DNA hypomethylation at early replicating domains. Together, our results suggest that there are two distinct mechanisms underlying replication timing-dependent recruitment of DNMT1 through PAF15Ub2 and H3Ub2, both of which are prerequisite for high fidelity DNA methylation inheritance

Dehydration of sorbitol to isosorbide over H-beta zeolites with high Si/Al ratios

Conversion of sorbitol to isosorbide by heterogeneous catalysts is a challenge in biorefinery. Herein, H-beta zeolites with specific Si/Al ratios uniquely give isosorbide in up to 76% yield under mild conditions. Mechanistic study has suggested that acid sites on hydrophobic internal surface are active for this reaction

AP-2β is a transcriptional regulator for determination of digit length in tetrapods

AbstractThe species-specific morphology of digits in the tetrapod limb, including the length and number of metacarpal, metatarsal, and phalangeal bones, suggests that a common developmental mechanism for digit formation is modified in a species-specific manner. Here, we examined the function of the AP-2β transcription factor in regulating digit length in the chicken autopod. Mutations in the gene encoding AP-2β are associated with Char syndrome, a human autosomal dominant disorder. Char syndrome patients exhibit autopod skeletal defects, including loss of phalanges and shortened fingers, suggestive of a function for AP-2β in normal digit development. The ectopic expression of two different dominant-negative forms of chick AP-2β, equivalent to mutant forms associated with human Char syndrome, in the developing chick hindlimb bud resulted in defective digit formation, including reductions in the number and length of phalanges and metatarsals. A detailed analysis of the AP-2β expression pattern in the limb bud indicated a correlation between the pattern/duration of AP-2β expression in the limb mesenchyme and digit length in three amniote species, the chicken, mouse and gecko. In addition, we found that AP-2β expression was downstream of Fgf signals from the apical ectodermal ridge, which is crucial in digit morphogenesis, and that excessive AP-2β function resulted in dysregulated digit length. Taken together, these results suggest that AP-2β functions as a novel transcriptional regulator for digit morphogenesis

Selective Dehydration of Mannitol to Isomannide over Hβ Zeolite

Isomannide is a potential feedstock for the production of super engineering plastics. A prospective route to obtain isomannide is dehydration of mannitol derived from lignocellulosic biomass, but homogeneous acid catalysts reported in the literature produce a large amount of 2,5-sorbitan as a byproduct in the dehydration reaction. In this work, we initially studied the mechanism of proton-induced dehydration of mannitol by density functional theory calculations, which suggested that local steric hindrance around acid sites designed at the angstrom level can tune the selectivity toward isomannide formation. Based on this prediction, we found that the precisely defined microporous confinement offered by Hβ provides improved selectivity and high catalytic activity for the production of isomannide, where 1,4-dehydration is favored by 20 kJ mol^–1 of activation energy. The optimization of the Si/Al ratio of Hβ to balance the acid amount and hydrophobicity improved the catalytic activity and achieved 63% yield of isomannide, far exceeding the best result reported previously (35% yield)