Solution Structure of IseA, an Inhibitor Protein of DL-Endopeptidases from Bacillus subtilis, Reveals a Novel Fold with a Characteristic Inhibitory Loop

In Bacillus subtilis, LytE, LytF, CwlS, and CwlO are vegetative autolysins, DL-endopeptidases in the NlpC/P60 family, and play essential roles in cell growth and separation. IseA (YoeB) is a proteinaceous inhibitor against the DL-endopeptidases, peptidoglycan hydrolases. Overexpression of IseA caused significantly long chained cell morphology, because IseA inhibits the cell separation DL-endopeptidases post-translationally. Here, we report the first three-dimensional structure of IseA, determined by NMR spectroscopy. The structure includes a single domain consisting of three alpha-helices, one 3(10)-helix, and eight beta-strands, which is a novel fold like a "hacksaw." Noteworthy is a dynamic loop between beta 4 and the 3(10)-helix, which resembles a "blade." The electrostatic potential distribution shows that most of the surface is positively charged, but the region around the loop is negatively charged. In contrast, the LytF active-site cleft is expected to be positively charged. NMR chemical shift perturbation of IseA interacting with LytF indicated that potential interaction sites are located around the loop. Furthermore, the IseA mutants D100K/D102K and G99P/G101P at the loop showed dramatic loss of inhibition activity against LytF, compared with wild-type IseA, indicating that the beta 4-3(10) loop plays an important role in inhibition. Moreover, we built a complex structure model of IseA-LytF by docking simulation, suggesting that the beta 4-3(10) loop of IseA gets stuck deep in the cleft of LytF, and the active site is occluded. These results suggest a novel inhibition mechanism of the hacksaw-like structure, which is different from known inhibitor proteins, through interactions around the characteristic loop regions with the active-site cleft of enzymes.ArticleJOURNAL OF BIOLOGICAL CHEMISTRY. 287(53):44736-44748 (2012)journal articl

Preliminary result of the relationship between the breathing frequency and dynamic body acceleration

March 5-6, 2009, Bangkok, ThailandIn this study, the relationship between the breathing frequency and the dynamic body acceleration (DBA) of one hatchery-reared loggerhead turtle Carretta carretta was examined using acceleration data loggers. Two acceleration data loggers (M190L-D2GT, W1000-3MPD3GT, Little Leonard, Japan) were attached on the lower-beak and carapace of a hatchery-reared loggerhead turtle, respectively. Breathing was successfully detected from the angle and depth of the beak-attached data logger and DBA, which has been used as an index of activity levels (Wilson et al., 2006), was calculated from the forward acceleration of the carapace-attached logger. There was a positive correlation between the DBA in the previous dive and the breathing frequency; the relationship was exponential. The result suggests that the number of breaths increased exponentially after a more active dive

Sacral Stress Fracture Complicated by L5 Radiculopathy in a Patient with Rheumatoid Arthritis

A 60-year-old Japanese woman with severe osteoporosis presented with a history of right buttock pain and right lateral lower leg pain in an L5 distribution. She had been treated with methotrexate and methylprednisolone for rheumatoid arthritis (RA) and interstitial pneumonia. Computed tomography demonstrated a sacral stress fracture in the right sacral ala. The right L5 nerve root was compressed by the fracture site. This case is rare in that L5 radiculopathy was complicated by a sacral stress fracture. Clinicians should suspect sacral stress fractures when RA or osteoporosis is present in women who experiences lumbar pain and lumbar radiculopathy

Epidermal growth factor signals regulate dihydropyrimidine dehydrogenase expression in EGFR-mutated non-small-cell lung cancer

Schematic diagrams of the signal cascade of EGF-induced DPD expression of EGFR-mutated type cells. TF, transcription factor; Mit A, mithramycin A. (JPG 130 kb

Relationship between serum ghrelin level and physiology in patients who underwent hepatectomy and pancreatectomy

Aim: Ghrelin is a peptide that is secreted from the stomach and plays a role in appetite, weight gain, and skeletal muscle composition.In the present clinical study, we examined the relationship between ghrelin level and physiology in patients who had undergone major liver and pancreas surgery. Methods: Serum ghrelin level was measured before and after hepatectomy and pancreatectomy. The relationships between nutritional status and postoperative alterations of parameters including the ghrelin level were examined. Results: In 32 patients, the preoperative plasm acyl- (AG) or des-acyl-ghrelin (DAG) and AG/DAG ratio were not significantly different based on gender, type of operation, age and each disease. AG tended to be correlated with the respiration quotient but this was not statistically significant (p=0.08). AG was significantly negatively correlated with hemoglobin and albumin levels. The postoperative plasma ghrelin level was significantly decreased at day 1 in comparison with preoperative levels (p<0.05) and recovered to preoperative levels at day 3. There were no significant differences between hepatectomy and pancreatectomy groups, with no changes of postoperative metabolic parameters. Conclusions: Although serum ghrelin level was transiently decreased, this level was immediately recovered and not influencedby the surgical procedures or its invasiveness

Effects of photodynamic therapy using talaporfin sodium (Laserphyrin® ) on wound healing in an animal model

Background: Photodynamic therapy (PDT) is an effective laser treatment for locally advanced carcinoma and is promising as neoadjuvant chemotherapy before surgery. The aim of this study was to clarify the adverse effects of PDT using a photosensitizer, talaporfin sodium (Laserphyrin®), for wound healing.Methodology: For PDT, a laser light with a wavelength of 660 nm and a frequency of 10 Hz with a total energy fluency of60 J/cm2 was used. Macroscopic and histological findings of wound healing after PDT were examined in vivo (4-week-old male BALB/c mice).Results: In Model 1, in which skin was cut at 0, 3, 7 days after PDT (n=3, each), wounds were similarly healed 7 days after cutting in all groups, and regenerating epithelium and the number of fibroblasts on histological findings were not different. In Model 2, in which skin defects were created before or after PDT, the size of the defects was larger at day 7 in the groups with skin defects before or after PDT in comparison with groups with no PDT.However, macroscopic wound healing at day 14 was complete in all groups and there were no significant differences among the groups by this point. Histological findings of skin defects at day 14 showed no significant difference in terms of regenerating epithelium and number of fibroblasts in each group with or without PDT.Conclusions: PDT did not influence wound healing and can be safely applied before surgical therapy

Associated factors with surgical site infections after hepatectomy: Predictions and countermeasures by a retrospective cohort study

Background: To clarify the factors associated with post-hepatectomy surgical site infections (SSIs), the clinicopathological data of 526 patients who underwent hepatectomy was retrospectively examined as a retrospectively cohort study. Methods: Patient demographics, liver functions, histological findings, surgical records and post-hepatectomy morbidity were compared between non-SSI and SSI groups; the SSI group included superficial and deep SSIs. Results: The prevalence of SSIs (5-8%) has not changed over an 18-year period. Deep SSIs were significantly more increased in male patients with lower performance statuses and American Society of Anesthesiologists (ASA) scores (p < 0.05). SSIs tended to be less prevalent, although not significant (p = 0.10), in patients who underwent laparoscopic hepatectomies compared to those who underwent laparotomies. For patients in whom hemostatic devices were used, the prevalence of superficial SSIs was significantly lower than those in whom the devices were not used (p < 0.05). Blood loss and transfusion were significantly more frequent in the deep SSI group compared to other groups (p < 0.01). Hospital stay in the deep SSI group was significantly longer compared to other groups. The incidence of morbidity was more frequent in the SSI groups compared with the non-SSI group (p < 0.001). A multivariate analysis showed that not using a vessel sealing device was significantly associated with superficial SSIs; male gender, hepatic failure and bile leakage were significantly associated with deep SSIs (p < 0.05). Conclusions: SSIs were important indicators of patient outcomes after hepatectomies, and preventing SSI development after surgical procedures is an important step in improving the overall prevalence of SSIs