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Laparoscopic liver resection (LLR) has been reported as a safe, minimally invasive, and effective surgery for the management of liver tumor. However, the efficacy and safety of laparoscopic repeat liver resection (LRLR) for recurrent liver tumor are unclear. Here, we analyzed the surgical results of LRLR. From June 2010 to May 2019, we performed 575 LLR surgeries in our department, and 454 of them underwent pure LLR for the single tumor. We classified the patients who received pure LLR for the single tumor into three groups: LRLR (n = 80), laparoscopic re-operation after previous abdominal surgery (LReOp; n = 136), and laparoscopic primary liver resection (LPLR; n = 238). We compared patient characteristics and surgical results between patients undergoing LRLR, LReOp and LPLR. We found no significant differences between LRLR and LPLR in the conversion rate to laparotomy (p = 0.8033), intraoperative bleeding (63.0 vs. 152.4 ml; p = 0.0911), or postoperative bile leakage rate (2.50 vs. 3.78%; p = 0.7367). We also found no significant difference in the surgical results between LReOp and LPLR. However, the number of patients undergoing the Pringle maneuver was lower in the LRLR group than the LPLR group (61.3 vs. 81.5%; p = 0.0004). This finding was more pronounced after open liver resection than laparoscopic liver resection (38.9 vs. 67.7%; p = 0.0270). The operative time was significantly longer in patients with proximity to previous cut surface than patients with no proximity to previous cut surface (307.4 vs. 235.7 min; p = 0.0201). LRLR can safely be performed with useful surgical results compared to LPLR.

Leaf development in plants, including dorsoventral (adaxial–abaxial) patterning, is tightly regulated. The involvement of several subunits of the 26S proteasome in adaxial–abaxial polarity establishment has been reported. In the present study, we revealed that in Arabidopsis thaliana, a mutation in RPT5A, a subunit of 26S proteasome, causes abnormally narrow true leaves under zinc deficiency. mRNA accumulations of DNA damage marker genes in leaves were elevated by zinc deficiency. PARP2, a single-strand break (SSB) inducible gene, was more strongly induced by zinc deficiency in rpt5a mutants compared with the wild type. A comet assay indicated that SSB is enhanced in mutants grown under the zinc deficiency condition. These results suggest that SSB accumulation is accompanied by abnormal leaf development. To test if DNA damage is a sole cause of abnormal leaf development, we treated the wild type grown under normal zinc conditions with zeocin, a DNA damage-inducing reagent, and found that narrow leaves developed, suggesting that DNA damage is sufficient to induce the development of abnormally narrow leaves. Taken together with the observation of the abnormal leaf morphology of our mutant plant under zinc deficiency, we demonstrated that the alleviation of DNA damage is important for normal leaf development.

Chromatin accessibility is closely associated with chromatin functions such as gene expression, DNA replication, and maintenance of DNA integrity. However, the relationship between chromatin accessibility and plant hormone signaling has remained elusive. Here, based on the correlation between chromatin accessibility and DNA damage, we used the sensitivity to DNA double strand breaks (DSBs) as an indicator of chromatin accessibility and demonstrated that auxin regulates chromatin accessibility through the TIR1/AFBs signaling pathway in proliferative cells. Treatment of proliferating plant cells with an inhibitor of the TIR1/AFBs auxin signaling pathway, PEO-IAA, caused chromatin loosening, indicating that auxin signaling functions to decrease chromatin accessibility. In addition, a transcriptome analysis revealed that several histone H4 genes and a histone chaperone gene, FAS1, are positively regulated through the TIR1/AFBs signaling pathway, suggesting that auxin plays a role in promoting nucleosome assembly. Analysis of the fas1 mutant of Arabidopsis thaliana confirmed that FAS1 is required for the auxin-dependent decrease in chromatin accessibility. These results suggest that the positive regulation of chromatin-related genes mediated by the TIR1/AFBs auxin signaling pathway enhances nucleosome assembly, resulting in decreased chromatin accessibility in proliferative cells.

Scientific Reports 6: Article number: 29657; published online: 15 July 2016; updated: 13 January 2017 In the original version of this Article, all instances of “sGFP” were incorrectly given as “EGFP”. This error has now been corrected in the PDF and HTML versions of the Article.

DNA replication is an essential process for the copying of genomic information in living organisms. Imaging of DNA replication in tissues and organs is mainly performed using fixed cells after incorporation of thymidine analogs. To establish a useful marker line to measure the duration of DNA replication and analyze the dynamics of DNA replication, we focused on the proliferating cell nuclear antigen (PCNA), which functions as a DNA sliding clamp for replicative DNA polymerases and is an essential component of replisomes. In this study we produced an Arabidopsis thaliana line expressing PCNA1 fused with the green fluorescent protein under the control of its own promoter (pAtPCNA1::AtPCNA1-sGFP). The duration of the S phase measured using the expression line was consistent with that measured after incorporation of a thymidine analog. Live cell imaging revealed that three distinct nuclear localization patterns (whole, dotted, and speckled) were sequentially observable. These whole, dotted, and speckled patterns of subnuclear AtPCNA1 signals were indicative of the G1 or G2 phase, early S phase and late S phase, respectively. The results indicate that the pAtPCNA1::AtPCNA1-sGFP line is a useful marker line for visualization of S-phase progression in live plant organs.