Involvement of S-adenosylmethionine-dependent halide/thiol methyltransferase (HTMT) in methyl halide emissions from agricultural plants: isolation and characterization of an HTMT-coding gene from Raphanus sativus (daikon radish)

<p>Abstract</p> <p>Background</p> <p>Biogenic emissions of methyl halides (CH₃Cl, CH₃Br and CH₃I) are the major source of these compounds in the atmosphere; however, there are few reports about the halide profiles and strengths of these emissions. Halide ion methyltransferase (HMT) and halide/thiol methyltransferase (HTMT) enzymes concerning these emissions have been purified and characterized from several organisms including marine algae, fungi, and higher plants; however, the correlation between emission profiles of methyl halides and the enzymatic properties of HMT/HTMT, and their role in vivo remains unclear.</p> <p>Results</p> <p>Thirty-five higher plant species were screened, and high CH₃I emissions and HMT/HTMT activities were found in higher plants belonging to the Poaceae family, including wheat (<it>Triticum aestivum </it>L.) and paddy rice (<it>Oryza sativa </it>L.), as well as the Brassicaceae family, including daikon radish (<it>Raphanus sativus</it>). The in vivo emission of CH₃I clearly correlated with HMT/HTMT activity. The emission of CH₃I from the sprouting leaves of <it>R. sativus</it>, <it>T. aestivum </it>and <it>O. sativa </it>grown hydroponically increased with increasing concentrations of supplied iodide. A gene encoding an <it>S</it>-adenosylmethionine halide/thiol methyltransferase (HTMT) was cloned from <it>R. sativus </it>and expressed in <it>Escherichia coli </it>as a soluble protein. The recombinant <it>R. sativus </it>HTMT (RsHTMT) was revealed to possess high specificity for iodide (I^-), bisulfide ([SH]^-), and thiocyanate ([SCN]^-) ions.</p> <p>Conclusion</p> <p>The present findings suggest that HMT/HTMT activity is present in several families of higher plants including Poaceae and Brassicaceae, and is involved in the formation of methyl halides. Moreover, it was found that the emission of methyl iodide from plants was affected by the iodide concentration in the cultures. The recombinant RsHTMT demonstrated enzymatic properties similar to those of <it>Brassica oleracea </it>HTMT, especially in terms of its high specificity for iodide, bisulfide, and thiocyanate ions. A survey of biogenic emissions of methyl halides strongly suggests that the HTM/HTMT reaction is the key to understanding the biogenesis of methyl halides and methylated sulfur compounds in nature.</p

Dislocation structure produced by an ultrashort shock pulse

We found an ultrashort shock pulse driven by a femtosecond laser pulse on iron generates a different dislocation structure than the shock process which is on the nanosecond timescale. The ultrashort shock pulse produces a highly dense dislocation structure that varies by depth. According to transmission electron microscopy, dislocations away from the surface produce microbands via a network structure similar to a long shock process, but unlike a long shock process dislocations near the surface have limited intersections. Considering the dislocation motion during the shock process, the structure near the surface is attributed to the ultrashort shock duration. This approach using an ultrashort shock pulse will lead to understanding the whole process off shock deformation by clarifying the early stage.Matsuda T., Sano T., Arakawa K., et al., Journal of Applied Physics, 116(18), 183506 (2014) https://doi.org/10.1063/1.490192

Multiple-shocks induced nanocrystallization in iron

We found that multiple shots of femtosecond laser-driven shock pulses changed coarse crystalline iron grains with a size of 140 μm into nanocrystals with a high density of dislocations, which had never been observed in conventional shock processes. We performed metallurgical microstructure observations using transmission electron microscopy (TEM) and hardness measurements using nanoindentation on cross-sections of shocked iron. TEM images showed that grains with sizes from 10 nm through 1 μm exist within 2 μm of the surface, where the dislocation density reached 2 × 10 15m-2. Results of the hardness measurements showed a significant increase in hardness in the nanocrystallized region. We suggest that the formation of a high density of dislocations, which is produced by a single shock, induces local three-dimensional pile-up by the multiple-shocks, which causes grain refinement at the nanoscale. © 2014 AIP Publishing LLC.Matsuda T., Sano T., Arakawa K., et al., Applied Physics Letters, 105(2), 021902 (2014) https://doi.org/10.1063/1.489038

Delayed Brain Edema and Swelling following Craniectomy for Evacuation of an Epidural Abscess that Improved by Cranioplasty: Case Report

We report a unique case of delayed brain swelling following craniectomy that improved rapidly after cranioplasty, and discuss the potential mechanism underlying this delayed and reversible brain swelling. A 22-year-old woman developed surgical site infection after removal of a convexity meningioma. Magnetic resonance imaging revealed an epidural abscess around the surgical site. Subsequently, the abscess was evacuated, and the bone flap was removed. Later, brain edema around the skull defect emerged and progressed gradually, despite resolution of the infection. The edematous brain developed focal swelling outward through the bone defect without ventricle dilatation. Because we suspected that the edema and swelling were caused by the state of the bone defect, we performed a cranioplasty 10 weeks after the bone flap removal, and brain edema improved rapidly. We hypothesized that the brain edema was initially caused by surgical stress and inflammation, followed by compression of cortical veins between the dural edge and brain tissue, leading to disruption of venous return and exacerbation of brain edema. When delayed focal brain edema and external swelling progress gradually after bone flap removal, after excluding other pathological conditions, cranioplasty should be considered to improve cortical venous congestion caused by postsurgical adhesion

The Prognosis for Unexpected Gallbladder Carcinoma with Bile Spillage during Laparoscopic Cholecystectomy

Here we review the prognosis of patients with unsuspected gallbladder carcinoma（GBC）, detected after laparoscopic cholecystectomy（LC）in a single institute. We reviewed the medical records of patients diagnosed with gallbladder stones on admission, who underwent LC. Carcinoma involving the gallbladder was found in 22 of 2,770 patients（0.9％）via postoperative pathological examination. This GBC group spanned 58-87 years of age（mean, 75 years; 13 females and 9 males）. The preoperative diagnosis was gallbladder stones with acute/chronic cholecystitis or adenomyomatosis of the gallbladder in all patients. We performed an additional surgery in 6 of 15 patients with pT2 and T3 disease; of these, 3 patients with pT2 disease and 1 with pT3 experienced bile spillage during the LC. The mean survival of patients with unexpected GBC was 21 months, with bile spillage occurring as a complication of LC identified as a potential risk factor for shorter survival（15.3 vs. 32.5 months）. We identified patients with pT2 and pT3 disease after LC, and two patients with pT2 and 1 with pT3 who had bile spillage during LC died of peritoneal dissemination within 28 months, despite additional surgery. Occasional seeding caused by bile spillage during LC should be carefully avoided to minimize the risk of developing unsuspected GBC after LC

Efficacy of surgical management for recurrent intrahepatic cholangiocarcinoma: A multi-institutional study by the Okayama Study Group of HBP surgery

Background The prognosis of intrahepatic cholangiocarcinoma (ICC) has been poor, because of the high recurrence rate even after curative surgery. This study aimed to evaluate the prognostic impact of surgical resection of recurrent ICC. Patients and methods A total of 345 cases of ICC who underwent hepatectomy with curative intent in 17 institutions were retrospectively analyzed, focusing on recurrence patterns and treatment modalities for recurrent ICC. Results Median survival time and overall 5-year recurrence-free survival rate were 17.8 months and 28.5%, respectively. Recurrences (n = 223) were classified as early (recurrence at 1 year, n = 92). Median survival time was poorer for early recurrence (16.3 months) than for late recurrence (47.7 months,p<0.0001). Treatment modalities for recurrence comprised surgical resection (n = 28), non-surgical treatment (n = 134), and best supportive care (BSC) (n = 61). Median and overall 1-/5-year survival rates after recurrence were 39.5 months and 84.6%/36.3% for surgical resection, 14.3 months and 62.5%/2.9% for non-surgical treatment, and 3 months and 4.8%/0% for BSC, respectively (p<0.0001). Multivariate analysis identified early recurrence, simultaneous intra- and extrahepatic recurrence, and surgical resection of recurrence as significant prognostic factors. In subgroup analyses, surgical resection may have positive prognostic impacts on intra- and extrahepatic recurrences, and even on early recurrence. However, simultaneous intra- and extrahepatic recurrence may not see any survival benefit from surgical management. Conclusion Surgical resection of recurrent ICC could improve survival after recurrence, especially for patients with intra- or extrahepatic recurrence as resectable oligo-metastases

The Surgical Benefits of Repeat Hepatectomy for Colorectal Liver Metastasis

The most common site of distant metastasis from colorectal cancer is the liver, and hepatectomy presents the best curative treatment for recurrence of colorectal liver metastasis （CRLM）. This study aimed to identify factors of prognostic value for repeat hepatectomy for CRLM and to determine whether a third such procedure could similarly produce favourable outcomes for CRLM. We analyzed data for 161 patients in our department with colorectal metastasis. Of these, 22 patients underwent repeat hepatectomy for recurrent metastasis, with 16 undergoing a second hepatectomy and 6 a third hepatectomy. We analyzed patient characteristics, tumor status, operation-related variables, and short- and long-term outcomes. Univariate analysis for repeat hepatectomy identified the following five prognostic risk factors: T factor （＞SE） of the primary cancer, number of tumors involved in the initial hepatectomy （＞5）, interval from first to second hepatectomy （＜1year）, number of tumors involved in second hepatectomy （＞3）, and post-operation time （＞30days）. By multivariate analysis, T factor （＞SE） of the primary cancer, number of tumors in the initial hepatectomy （＞5）, and number of tumors in the second hepatectomy （＞3） were independently associated with a worse survival after surgery for CRLM. Although surgical outcomes of the third hepatectomy were not compared with those of the first and second hepatectomy, there were no obvious differences, nor did the 1-, 3-, and 5-year survival rates differ significantly among the three groups. Repeat hepatectomy for CRLM could improve long-term survival. In addition, patients undergoing a third hepatectomy showed a similar survival benefit to those having one or two resections

Regulation of Pancreatic β Cell Mass by Cross-Interaction between CCAAT Enhancer Binding Protein β Induced by Endoplasmic Reticulum Stress and AMP-Activated Protein Kinase Activity

During the development of type 2 diabetes, endoplasmic reticulum (ER) stress leads to not only insulin resistance but also to pancreatic beta cell failure. Conversely, cell function under various stressed conditions can be restored by reducing ER stress by activating AMP-activated protein kinase (AMPK). However, the details of this mechanism are still obscure. Therefore, the current study aims to elucidate the role of AMPK activity during ER stress-associated pancreatic beta cell failure. MIN6 cells were loaded with 5-amino-1-ϐ-D-ribofuranosyl-imidazole-4-carboxamide (AICAR) and metformin to assess the relationship between AMPK activity and CCAAT enhancer binding protein ϐ (C/EBPϐ) expression levels. The effect of C/EBPϐ phosphorylation on expression levels was also investigated. Vildagliptin and metformin were administered to pancreatic beta cell-specific C/EBPϐ transgenic mice to investigate the relationship between C/EBPϐ expression levels and AMPK activity in the pancreatic islets. When pancreatic beta cells are exposed to ER stress, the accumulation of the transcription factor C/EBPϐ lowers the AMP/ATP ratio, thereby decreasing AMPK activity. In an opposite manner, incubation of MIN6 cells with AICAR or metformin activated AMPK, which suppressed C/EBPϐ expression. In addition, administration of the dipeptidyl peptidase-4 inhibitor vildagliptin and metformin to pancreatic beta cell-specific C/EBPϐ transgenic mice decreased C/EBPϐ expression levels and enhanced pancreatic beta cell mass in proportion to the recovery of AMPK activity. Enhanced C/EBPϐ expression and decreased AMPK activity act synergistically to induce ER stress-associated pancreatic beta cell failure