Sequence-specific cleavage of RNA by a hybrid ribonuclease H

AbstractSite-specific cleavage of the 22-, 132- and 534-base RNAs by the DNA/protein hybrid R Nase H were examined. The 22-base RNA was chemically synthesized, and 132- and 534-base RNAs were prepared by run-off transcription. The hybrid enzyme cleaves these RNAs, which contain a single target sequence, primarily at the unique phosphodiester bond within the target sequence. The hybrid enzyme performs multiple turnovers, and at a substrate/enzyme ratio of 10:1 the RNAs are almost completely cleaved by the hybrid enzyme at 37°C within 1 h. We propose that hybrid RNase H molecules with various oligodeoxyribonucleotides function as RNA restriction enzymes and are useful for structural and functional studies of RNA

Psychological Stress-Induced Oxidative Stress as a Model of Sub-Healthy Condition and the Effect of TCM

Distress-mediated tissue oxidative stress was examined as a model of sub-healthy condition defined in traditional Chinese medicine theory. Mice were subjected to psychologically stressful conditions by whiskers removal. Under this condition, spontaneous locomotive activity was significantly enhanced in the dark (P < 0.05 versus the control mice in three different movements), and granulocytes/lymphocytes balance shifted to granulocytes. At the same time, peroxynitrite level in blood plasma increased to ∼180% from that of the control mice at 6 h after removal of the whiskers (P < 0.01), and was maintained even after 12 h. Both protein carbonyl formation and lipid peroxidation were significantly increased under this condition in brain, heart, liver and spleen at 6 h after removal of whiskers (P < 0.05 or P < 0.01), and these levels were maximized after 12 h (increased to 120–160%, P < 0.05 or P < 0.01). The oxidative tissue injuries observed at 12 h after the removal of the whiskers were effectively prevented by two traditional Chinese medicine formula: Shengmai San (SMS) and Ling Gui Zhu Gan Tang (LGZGT), when administered for 5 days before the removal of the whiskers. Therefore, this stress model is considered useful in assessing the preventive potential of antioxidants and antioxidant-based herbal mixtures in treating the pathophysiology associated with psychological or emotional distress

HPF1-dependent PARP activation promotes LIG3-XRCC1-mediated backup pathway of Okazaki fragment ligation

DNA ligase 1 (LIG1) is known as the major DNA ligase responsible for Okazaki fragment joining. Recent studies have implicated LIG3 complexed with XRCC1 as an alternative player in Okazaki fragment joining in cases where LIG1 is not functional, although the underlying mechanisms are largely unknown. Here, using a cell-free system derived from Xenopus egg extracts, we demonstrated the essential role of PARP1-HPF1 in LIG3-dependent Okazaki fragment joining. We found that Okazaki fragments were eventually ligated even in the absence of LIG1, employing in its place LIG3-XRCC1, which was recruited onto chromatin. Concomitantly, LIG1 deficiency induces ADP-ribosylation of histone H3 in a PARP1-HPF1-dependent manner. The depletion of PARP1 or HPF1 resulted in a failure to recruit LIG3 onto chromatin and a subsequent failure in Okazaki fragment joining in LIG1-depleted extracts. Importantly, Okazaki fragments were not ligated at all when LIG1 and XRCC1 were co-depleted. Our results suggest that a unique form of ADP-ribosylation signaling promotes the recruitment of LIG3 on chromatin and its mediation of Okazaki fragment joining as a backup system for LIG1 perturbation

Groin lymph node detection and sentinel lymph node biopsy in vulvar cancer

Objective: To identify suitable diagnostic tools and evaluate the efficacy of sentinel lymph node (SLN) biopsy for inguinal lymph node metastasis in vulvar cancer. Methods: Data from 41 patients with vulvar cancer were evaluated retrospectively, including magnetic resonance imaging (MRI) measurements, SLN biopsy status, groin lymph node metastasis, and prognosis. Results: SLN biopsy was conducted in 12 patients who had stage I to III disease. Groin lymphadenectomy was omitted in five of the nine patients with negative SLNs. All SLN-negative patients who did not undergo groin lymphadenectomy showed no evidence of disease after treatment. On MRI, the long and short diameters of the inguinal node were significantly longer in metastasis-positive cases, compared with negative cases, in 25 patients whose nodes were evaluated pathologically (long diameter, 12.8 mm vs. 8.8 mm, p=0.025; short diameter, 9.2 mm vs. 6.7 mm, p=0.041). The threshold of >10.0 mm for the long axis gave a sensitivity, specificity, positive predictive value, and negative predictive value of 87.5%, 70.6%, 58.3%, and 92.3%, respectively, using a binary classification test. Decision tree analysis revealed a sensitivity, specificity, and accuracy of 87.5%, 70.6%, and 76.0%, respectively, with the threshold of >10.0 mm for the long axis on MRI. The criteria of >10.0 mm for the long axis on MRI predicted an advanced stage and poorer prognosis using a validation set of 15 cases (p=0.028). Conclusion: Minimally invasive surgery after preoperative evaluation on MRI and SLN biopsy is a feasible strategy for patients with vulvar cancer

Preventive effects of TCM on TBARS formation in tissues under whiskers cut stress in mice

<p><b>Copyright information:</b></p><p>Taken from "Psychological Stress-Induced Oxidative Stress as a Model of Sub-Healthy Condition and the Effect of TCM"</p><p></p><p>Evidence-based Complementary and Alternative Medicine 2006;4(2):195-202.</p><p>Published online 2 Nov 2006</p><p>PMCID:PMC1876613.</p><p>© 2006 The Author(s).</p> SMS or LGZGT were the same as in . At 12 h after whiskers removal, tissues were removed to determine TBARS. Data represent means ± SD ( = 6 mice). < 0.05 or < 0.01 versus the untreated control mice. < 0.05 or < 0.01 versus stressed mice

Effect of whiskers cut stress and Shengmai San on locomotive activities of mice at night

<p><b>Copyright information:</b></p><p>Taken from "Psychological Stress-Induced Oxidative Stress as a Model of Sub-Healthy Condition and the Effect of TCM"</p><p></p><p>Evidence-based Complementary and Alternative Medicine 2006;4(2):195-202.</p><p>Published online 2 Nov 2006</p><p>PMCID:PMC1876613.</p><p>© 2006 The Author(s).</p> SMS was orally administered to mice once a day for 5 days, after which the mice were distressed by whiskers removal. Three types of behavioral movements (small and large movements, and rearing) were then recorded in five mice for 12 h at night. Values represent the means ± SD (frequency within 12 h per five mice) of three independent experiments.  = 5. < 0.05, < 0.01 compared to the control (unstressed) mice; < 0.05, < 0.01 compared to the stressed mice