Fractionation of cassava pectins and their detailed structural analyses using various pectinolytic enzymes.

In this study, we analyzed the pectin structure within the pulp of cassava. Cassava pectin, derived from cassava pulp treatment at 120 °C for 90 min, was separated into four fractions (CP-P, CP-SD1, CP-SD2F, and CP-SD2R) based on variations in water solubility, electrical properties, and molecular weights. Sugar composition analysis demonstrated an abundance of homogalacturonan (HG) in CP-P and CP-SD2F, rhamnogalacturonan I (RG-I) in CP-SD2R, and neutral sugars in CP-SD1. Because RG-I possesses a complex structure, we analyzed CP-SD2R using various pectinolytic enzymes. Galactose was the major sugar in CP-SD2R accounting for 49 %, of which 65 % originated from arabinogalactan I, 9 % from galactose and galactooligosaccharides, 5 % from arabinogalactan II, and 11 % from galactoarabinan. Seventy-four percent of arabinose in CP-SD2R was present as galactoarabinan. The methylation (DM) and acetylation (DAc) degrees of cassava pectin were 11 and 15 %, respectively. The HG and RG-I regions exhibited DAc values of 5 and 44 %, respectively, signifying the high DAc of RG-I compared to HG. Information derived from the structural analysis of cassava pectin will enable efficient degradation of pectin and cellulose, leading to the use of cassava pulp as a raw material for biorefineries.

Gelation of konjac glucomannan by acetylmannan esterases from Aspergillus oryzae.

Konjac glucomannan (KGM) is a principal component of the gelatinous food Konjac. Konjac production through alkali treatment releases an undesirable amine-odor. Two acetylesterases (AME1 and AME2) active against konjac glucomannan (polymer or oligomer) were purified from the supernatant of Aspergillus oryzae RIB40 culture. We cloned the genes encoding AME1 and AME2 based on the genomic information of A. oryzae, constructed their expression systems in A. oryzae, and obtained the recombinant enzymes (rAME1 and rAME2). rAME1 did not act on the KGM polymer but only on the KGM oligomer, releasing approximately 60% of the acetic acid in the substrate. However, rAME2 was active against both KGM substrates, releasing approximately 80% and 100% of acetic acid from the polymer and oligomer, respectively. Both enzymes were active against xylan and exhibited a trace activity on ethyl ferulate. The acetyl group position specificities of both enzymes were analyzed via heteronuclear single quantum correlation NMR using oligosaccharides of glucomannan prepared from Aloe vera (AGM), which has a higher acetyl group content than KGM. rAME1 acted specifically on single-substituted acetyl groups and not on double-substituted ones. In contrast, rAME2 appeared to act on all the acetyl groups in AGM. Treatment of 3% KGM with rAME2 followed by heating to 90 °C resulted in gel formation under weakly acidic conditions. This is the first study to induce gelation of KGM under these conditions. A comparison of the breaking and brittleness properties of gels formed by alkaline and enzymatic treatments revealed similar texture of the two gels. Furthermore, scanning electron microscopy of the surface structure of both gels revealed that both formed a fine mesh structure. Our findings on enzymatic gelation of KGM should lead to the development of new applications in food manufacturing industry.

Use of a highly sensitive lung cancer compact panel to detect KRAS G12D in the wash fluid from a lung tumor: A case report.

Here, we report a case of a pulmonary invasive mucinous adenocarcinoma harboring KRAS G12D, diagnosed from tumor samples containing a very small amount of tumor cells using next-generation sequencing (NGS) and the recently developed Lung Cancer Compact Panel. A 79-year-old woman without any respiratory symptoms underwent chest computed tomography, which revealed a tumor in the left lower lobe. During endobronchial ultrasound (EBUS)-guided transbronchial biopsy (TBB) using a guide sheath (GS), a sufficient specimen for pathological diagnosis could not be obtained because the patient had a severe cough and pulmonary bullae located adjacent to the tumor. In the absence of EBUS transbronchial biopsy findings using a guide sheath, brush cytology was used to categorize the tumor as class II (Papanicolaou classification). However, the wash fluid from the cytological examination contained enough cells to obtain sufficient nucleic acid for use in sequencing analysis. The latter revealed KRAS G12D expression. Although the patient underwent surgery without pathological evidence, the evaluation of the surgical specimen confirmed a diagnosis of pulmonary invasive mucinous adenocarcinoma. Use of the Lung Cancer Compact Panel enabled the detection of KRAS G12D in the wash fluid of a brush cytology sample and thus a diagnosis of pulmonary invasive mucinous adenocarcinoma.

Novel acid trehalase belonging to glycoside hydrolase family 37 from Pleurotus sp.: cloning, expression and characterization.

The N-terminal amino acid sequence of the Pleurotus sp. 90 kDa protein was in good agreement with the corresponding sequence of the glycoside hydrolase (GH) family 37 protein (trehalase) from P. ostreatus PC 15 v2.0. The length of the Pleurotus sp. trehalase gene was 2247 bp, encoding a protein of 749 amino acids with a predicted molecular mass of 81.2 kDa. The molecular mass of the recombinant enzyme was estimated to be about 117 kDa by SDS-PAGE. We found that the recombinant enzyme comprised an N-glycosylated sugar chain and that its optimum pH and temperature were 4.5 and 40 ºC, respectively. Moreover, this enzyme exhibited high activity against trehalose exclusively. We found that the enzyme is novel acid trehalase belonging to GH family 37.

Delayed bronchial perforation after bulla cauterization with soft coagulation system.

BACKGROUND: Soft coagulation is widely used for hemostasis because of its significant advantage in inducing tissue coagulation and denaturation without carbonization. However, a few cases of airway damage have been reported at the site, where soft coagulation was directly applied. CASE PRESENTATION: We encountered an unusual case of delayed perforation of the intermediate bronchial trunk observed on 24 days after cauterization of the right S6 bulla adjacent to the bronchus. Chest computed tomography revealed a large fistula between the intermediate bronchial trunk and the cauterized bulla in the right S6. Bronchoscopy showed a large fistula at the membranous portion of the intermediate bronchial trunk. We presumed that the bronchial perforation resulted from thermal damage to the intermediate bronchial trunk during bulla cauterization and the bronchial perforation induced infection in the bulla. Resection of the infectious bulla and the intermediate bronchial trunk, followed by end-to-end bronchial anastomosis and a pedicled intercostal muscle flap coverage, was performed. CONCLUSIONS: The severe airway damage resulting in perforation developed even without direct contact between the electrode tip and the bronchial wall, provoking the need for special attention to the duration of cauterization and location, where it is used.

NADPH-to-NADH conversion by mitochondrial transhydrogenase is indispensable for sustaining anaerobic metabolism in Euglena gracilis.

Euglena gracilis produces ATP in the anaerobic mitochondria with concomitant wax ester formation, and NADH is essential for ATP formation and fatty acid synthesis in the mitochondria. This study demonstrated that mitochondrial cofactor conversion by nicotinamide nucleotide transhydrogenase (NNT), converting NADPH/NAD+ to NADP+ /NADH, is indispensable for sustaining anaerobic metabolism. Silencing of NNT genes significantly decreased wax ester production and cellular viability during anaerobiosis but had no such marked effects under aerobic conditions. An analogous phenotype was observed in the silencing of the gene encoding a mitochondrial NADP+ -dependent malic enzyme. These results suggest that the reducing equivalents produced in glycolysis are shuttled to the mitochondria as malate, where cytosolic NAD+ regeneration is coupled with mitochondrial NADPH generation.

Chemical Modification of Phage-Displayed Helix-Loop-Helix Peptides to Construct Kinase-Focused Libraries.

Conformationally constrained peptides hold promise as molecular tools in chemical biology and as a new modality in drug discovery. The construction and screening of a target-focused library could be a promising approach for the generation of de novo ligands or inhibitors against target proteins. Here, we have prepared a protein kinase-focused library by chemically modifying helix-loop-helix (HLH) peptides displayed on phage and subsequently tethered to adenosine. The library was screened against aurora kinase A (AurA). The selected HLH peptide Bip-3 retained the α-helical structure and bound to AurA with a KD value of 13.7 µM. Bip-3 and the adenosine-tethered peptide Bip-3-Adc provided IC50 values of 103 µM and 7.7 µM, respectively, suggesting that Bip-3-Adc bivalently inhibited AurA. In addition, the selectivity of Bip-3-Adc to several protein kinases was tested, and was highest against AurA. These results demonstrate that chemical modification can enable the construction of a kinase-focused library of phage-displayed HLH peptides.

Homogalacturonan and xylogalacturonan region specificity of self-cloning vector-expressed pectin methylesterases (AoPME1-3) in Aspergillus oryzae.

Aspergillus oryzae is a safe microorganism that is commonly used in food production. We constructed a self-cloning vector capable of high expression in A. oryzae. Using the vector, three putative pectin methylesterase (PME) genes belonging to Carbohydrate Esterase family 8 derived from A. oryzae were expressed, and several characteristics of the gene products were examined. The effects of temperature and pH on the three enzymes (AoPME1, 2, and 3) were similar, with optimal reaction temperatures of 50 - 60 °C and optimal reaction pH range of 5 - 6. The specific activities of AoPME1, 2, and 3 for apple pectin were significantly different (34, 7,601, and 2 U/mg, respectively). When the substrate specificity was examined, AoPME1 showed high activity towards pectin derived from soybean and pea. Although AoPME2 showed little activity towards these pectins, it showed very high activity towards apple- and citrus-derived pectins. AoPME3 showed low specific activity towards all substrates tested. Sugar composition analysis revealed that apple- and citrus-derived pectins were rich in homogalacturonan, while soybean- and pea-derived pectins were rich in xylogalacturonan. When pea pectin was treated with endo-polygalacturonase or endo-xylogalacturonase in the presence of each PME, specific synergistic actions were observed (endo-polygalacturonase with AoPME1 or AoPME2 and endo-xylogalacturonase with AoPME1 or AoPME3). Thus, AoPME1 and AoPME3 hydrolyzed the methoxy group in xylogalacturonan. This is the first report of this activity in microbial enzymes. Our findings on the substrate specificity of PMEs should lead to the determination of the distribution of methoxy groups in pectin and the development of new applications in the field of food manufacturing.

Novel cold-adapted raw-starch digesting α-amylases from Eisenia fetida: Gene cloning, expression, and characterization.

We identified the raw-starch-digesting α-amylase genes a earthworm Eisenia fetid α amylase I and II (Ef-Amy I and Ef-Amy II). Each gene consists of 1,530 base pairs (bp) that encode proteins of 510 amino acids, as indicated by the corresponding mRNA sequences. Ef-Amy I and II showed an 89% amino acid identity. The amino acid sequences of Ef-Amy I and II were similar to those of the α-amylases from porcine pancreas, human pancreas, Tenebrio molitor, Oryctolagus cuniculus, and Xenopus (Silurana) tropicalis. Each gene encoding mature Ef-Amy I and II was expressed in the GS115 strain of Pichia pastoris. The molecular masses of the recombinant Ef-Amy I and II were 57 kDa each, and catalytically important residues of α-amylases of the GH family 13 were conserved in both proteins. These amylases exhibited raw-starch-digesting activity at 4 °C. The substrate specificities of rEf-Amy I and II were dissimilar. rEf-Amy I and II were shown to be active even in 40% ethanol, 4 M NaCl, and 4 M KCl.

Solitary Splenic Metastasis of Lung Cancer Presenting as Benign Cystic Disease.

Solitary splenic metastasis from primary lung cancer is extremely rare. Here, we demonstrated a solitary splenic metastasis of primary lung cancer that was difficult to distinguish from benign cystic disease. A 69-year-old-female was diagnosed as middle lobe lung cancer. Although preoperative abdominal computed tomography (CT) demonstrated a low-density splenic nodule, fluorodeoxyglucose-positron emission tomography (FDG-PET) revealed no fluorodeoxyglucose uptake in the splenic nodule. Therefore, the nodule was diagnosed as benign cystic disease and middle lobe lobectomy was performed. Postoperative pathologic examination demonstrated papillary-predominant adenocarcinoma with mucin, and the tumor was diagnosed as primary lung cancer. However, the splenic nodule continued to increase postoperatively. Splenectomy was undergone 30 months after the pulmonary resection and the splenic tumor was diagnosed as the splenic metastasis of lung cancer. In the 24 months since the splenectomy, no recurrence has been observed in the absence of treatment. Splenectomy was an effective treatment for solitary splenic metastasis of lung cancer in this case. FDG uptake in the splenic tumor was not evident due to marked mucus production.

Iatrogenic bronchial injury findings during video-assisted thoracoscopic surgery.

Iatrogenic tracheobronchial injury detected during cardiothoracic surgery should be repaired intraoperatively to ensure safe of postoperative management and stable respiratory conditions. We report herein a patient with lung cancer who underwent video-assisted thoracoscopic surgery right lower lobectomy. During surgery, pneumomediastinum and air leakage from mediastinal fatty tissue were detected. Furthermore, bronchial injury to the membranous part of the left main bronchus was incidentally detected. Hence, we switched from video-assisted thoracoscopic surgery to posterolateral thoracotomy and repaired this bronchial injury using a continuous suture technique under right femoral venoarterial extracorporeal membrane oxygenation support. The intraoperative findings could offer a clue for early detection and development of therapeutic strategy for iatrogenic tracheobronchial injury.

Site-Selective Alkenylation of Unactivated C(sp3 )-H Bonds Mediated by Compact Sulfate Radical.

A broad variety of unactivated acyclic and alicyclic substrates cleanly undergo site-selective alkenylation of unactivated C(sp3 )-H bonds with 1,2-bis(phenylsulfonyl)ethene in the presence of persulfate. This simple transformation furnishes (E)-2-alkylvinylphenylsulfones in up to 88 % yield. In contrast with the previously reported decatungstate protocol, the current method is applicable to alkenylation of sterically hindered C-H bonds. This important advantage significantly broadens the substrate scope, and is attributed to the compact size of the sulfate radical employed in the C-H activation and cleavage.

Contralateral tension pneumothorax during video-assisted thoracic surgery for lung cancer in a patient with obesity and rib fractures: a case report and review of the literature.

BACKGROUND: Intraoperative contralateral pneumothorax during one-lung ventilation is a rare but life-threatening complication. Although the exact incidence is unknown, only 14 cases with this complication have been reported until now. CASE PRESENTATION: A 67-year-old Japanese man with a weight of 80 kg, height of 162.2 cm, and body mass index of 30.4 kg/m2 underwent three-port video-assisted thoracic surgery for lung cancer with one-lung ventilation. He had suffered from traumatic right rib fractures 6 weeks before the referral. Fifteen minutes before the end of the surgery, the systolic blood pressure suddenly dropped to about 50 mmHg, which was immediately recovered by intravenous injection of phenylephrine. This episode occurred during chest closure after the completion of the left upper lobectomy, and one-lung ventilation was soon switched to two-lung ventilation. Contralateral tension pneumothorax was noted by the postoperative chest x-ray. As the patient was complicated with obesity and a past history of rib fractures, increased airway pressure during one-lung ventilation related to obesity together with the persistent compression of the visceral pleura by the fractured ends of the ribs was considered to be the factors responsible for this critical complication. CONCLUSIONS: Patient backgrounds such as obesity and past history of rib fractures should be noted carefully as risk factors for intraoperative contralateral pneumothorax during one-lung ventilation. We present the clinical course and discuss the mechanism of development of this potentially life-threatening complication in the present case with a review of the literature.

Case report of thoracoscopic resection for broncholithiasis with severe obstructive pneumonia.

Broncholithiasis is a rare disease characterized by bronchial erosion or distortion due to hilar or parenchymatous calcification. When a broncholith has no mobility and there is a risk of major bleeding if removal is attempted, surgical intervention is required. Most operations for broncholithiasis are performed via a thoracotomy, and bronchial lithotripsy under complete video-assisted thoracoscopic surgery has been reported only rarely. We have experienced a case of broncholithiasis with severe obstructive pneumonia that was treated successfully by video-assisted thoracoscopic surgery. Thoracoscopic surgery is an effective treatment for broncholithiasis because it is minimally invasive and aids smooth recovery after surgery. When the adhesion between the pulmonary artery and the bronchus is highly advanced, it is advocated to cut them together using an endostapler.

X-ray crystallographic structural studies of α-amylase I from Eisenia fetida.

The earthworm Eisenia fetida possesses several cold-active enzymes, including α-amylase, ß-glucanase and ß-mannanase. E. fetida possesses two isoforms of α-amylase (Ef-Amy I and II) to digest raw starch. Ef-Amy I retains its catalytic activity at temperatures below 10°C. To identify the molecular properties of Ef-Amy I, X-ray crystal structures were determined of the wild type and of the inactive E249Q mutant. Ef-Amy I has structural similarities to mammalian α-amylases, including the porcine pancreatic and human pancreatic α-amylases. Structural comparisons of the overall structures as well as of the Ca2+-binding sites of Ef-Amy I and the mammalian α-amylases indicate that Ef-Amy I has increased structural flexibility and more solvent-exposed acidic residues. These structural features of Ef-Amy I may contribute to its observed catalytic activity at low temperatures, as many cold-adapted enzymes have similar structural properties. The structure of the substrate complex of the inactive mutant of Ef-Amy I shows that a maltohexaose molecule is bound in the active site and a maltotetraose molecule is bound in the cleft between the N- and C-terminal domains. The recognition of substrate molecules by Ef-Amy I exhibits some differences from that observed in structures of human pancreatic α-amylase. This result provides insights into the structural modulation of the recognition of substrates and inhibitors.

High Reactivity of α-Boryl Radical of Potassium Alkyltrifluoroborate in Atom-Transfer Radical Addition.

We found that the α-boryl radical of potassium alkyltrifluoroborate shows higher reactivity compared to the α-boryl radicals of alkylboronic acid pinacol ester and alkyl N-methyl imidodiacetic acid (MIDA) boronate in the halogen atom abstraction step of atom-transfer radical addition (ATRA) between alkyl bromide and vinylborons. In this research, an ATRA of alkyl halides with potassium vinyltrifluoroborate furnished unique alkylborons, which are difficult to synthesize by other methods.

Determination of chemical structure of pea pectin by using pectinolytic enzymes.

The chemical structure of pea pectin was delineated using pectin-degrading enzymes and biochemical methods. The molecular weight of the pea pectin preparation was 488,000, with 50 % arabinose content, and neutral sugar side chains attached to approximately 60 % of the rhamnose residues in rhamnogalacturonan-I (RG-I). Arabinan, an RG-I side chain, was highly branched, and the main chain was comprised of α-1,5-l-arabinan. Galactose and galactooligosaccharides were attached to approximately 35 % of the rhamnose residues in RG-I. Long chain ß-1,4-galactan was also present. The xylose substitution rate in xylogalacturonan (XGA) was 63 %. The molar ratio of RG-I/homogalacturonan (HG)/XGA in the backbone of the pea pectin was approximately 3:3:4. When considering neutral sugar side chain content (arabinose, galactose, and xylose), the molar ratio of RG-I/HG/XGA regions in the pea pectin was 7:1:2. These data will help understand the properties of pea pectin.

Characterization of three GH35 ß-galactosidases, enzymes able to shave galactosyl residues linked to rhamnogalacturonan in pectin, from Penicillium chrysogenum 31B.

Three recombinant ß-galactosidases (BGALs; PcBGAL35A, PcBGAL35B, and PcGALX35C) belonging to the glycoside hydrolase (GH) family 35 derived from Penicillium chrysogenum 31B were expressed using Pichia pastoris and characterized. PcBGAL35A showed a unique substrate specificity that has not been reported so far. Based on the results of enzymological tests and 1H-nuclear magnetic resonance, PcBGAL35A was found to hydrolyze ß-1,4-galactosyl residues linked to L-rhamnose in rhamnogalacturonan-I (RG-I) of pectin, as well as p-nitrophenyl-ß-D-galactopyranoside and ß-D-galactosyl oligosaccharides. PcBGAL35B was determined to be a common BGAL through molecular phylogenetic tree and substrate specificity analysis. PcGALX35C was found to have similar catalytic capacities for the ß-1,4-galactosyl oligomer and polymer. Furthermore, PcGALX35C hydrolyzed RG-I-linked ß-1,4-galactosyl oligosaccharide side chains with a degree of polymerization of 2 or higher in pectin. The amino acid sequence similarity of PcBGAL35A was approximately 30% with most GH35 BGALs, whose enzymatic properties have been characterized. The amino acid sequence of PcBGAL35B was approximately 80% identical to those of BGALs from Penicillium sp. The amino acid sequence of PcGALX35C was classified into the same phylogenetic group as PcBGAL35A. Pfam analysis revealed that the three BGALs had five domains including a catalytic domain. Our findings suggest that PcBGAL35A and PcGALX35C are enzymes involved in the degradation of galactosylated RG-I in pectin. The enzymes characterized in this study may be applied for products that require pectin processing and for the structural analysis of pectin.

Preoperative Smoking Cessation Period Is Not Related to Postoperative Respiratory Complications in Patients Undergoing Lung Cancer Surgery.

PURPOSE: Smoking is reported to be a risk factor for postoperative complications. However, there is no consensus regarding the length of time for which patients need to give up smoking. Therefore, we examined the relationship between preoperative smoking status and postoperative complications in patients who underwent lobectomy for treatment of lung cancer. METHODS: Between January 2009 and December 2014, 1380 patients underwent lobectomy for lung cancer at our institution. After excluding patients who had undergone induction therapy, 1248 patients were enrolled in this study. We examined the relationship between postoperative complications and preoperative smoking habitation. RESULTS: Among the enrolled patients, 1210 (97%) underwent video-assisted thoracoscopic lobectomy and 38 (3%) underwent lobectomy via open thoracotomy. The incidence of postoperative complications was higher in smokers than in nonsmokers, and the frequency of respiratory-related complications increased along with the number of pack-years. However, there was no relationship between the length of the preoperative smoking cessation period and the frequency of postoperative complications. CONCLUSION: The risk of postoperative complications does not increase even if smoking is continued within 2 weeks before surgery. It seems unnecessary to delay the timing of surgery to allow patients to cease smoking, especially those scheduled for thoracoscopic surgery.