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In free-living and parasitic nematodes, the methylation of phosphoethanolamine to phosphocholine provides a key metabolite to sustain phospholipid biosynthesis for growth and development. Because the phosphoethanolamine methyltransferases (PMT) of nematodes are essential for normal growth and development, these enzymes are potential targets of inhibitor design. The pine wilt nematode (Bursaphelenchus xylophilus) causes extensive damage to trees used for lumber and paper in Asia. As a first step toward testing BxPMT1 as a potential nematicide target, we determined the 2.05 Å resolution x-ray crystal structure of the enzyme as a dead-end complex with phosphoethanolamine and S-adenosylhomocysteine. The three-dimensional structure of BxPMT1 served as a template for site-directed mutagenesis to probe the contribution of active site residues to catalysis and phosphoethanolamine binding using steady-state kinetic analysis. Biochemical analysis of the mutants identifies key residues on the β1d-α6 loop (W123F, M126I, and Y127F) and β1e-α7 loop (S155A, S160A, H170A, T178V, and Y180F) that form the phosphobase binding site and suggest that Tyr127 facilitates the methylation reaction in BxPMT1., Competing Interests: Declaration of Competing Interest The authors have no conflicting interests., (Copyright © 2020 Elsevier B.V. All rights reserved.)

CT guided percutaneous fine needle aspiration biopsy was performed on 30 patients with pancreatic and periampullary neoplasms, in the Department of Surgery, China-Japan Friendship Hospital, between March 1985 and January 1986. We obtained positive cytodiagnosis from all cases of carcinoma of the pancreatic head (9 cases), body and tail (4 cases), and ampullary carcinomas (5 cases) (100 per cent). In 2 of 3 duodenal carcinomas (66.6 per cent), and 6 of 7 distal common duct carcinomas (86 per cent), a positive cytodiagnosis was also obtained. On the other hand, 2 cases of pancreatitis both gave a negative cytodiagnosis, i.e. no false positives were obtained. Out of the 30 cases who underwent CT guided biopsy, a correct diagnosis was obtained in 28, i.e. a diagnostic accuracy of 93.3 per cent. The cytodiagnosis of the other two cases was either suspicious or false negative. There have been no clinical complications noted.