Detailed active site configuration of a new crystal form of methanol dehydrogenase from Methylophilus W3A1 at 1.9 A resolution

The three-dimensional structure of a new crystal form of methanol dehydrogenase from Methylophilus W3A1 has been obtained in the presence of substrate using data recorded at a synchrotron. The structure of this approximately 140 kDa heterotetramer, refined at 1. 9 A resolution, reveals the detailed configuration of its redox cofactor, pyrroloquinoline quinone (PQQ). C4, one of the oxygen-bearing atoms of this orthoquinone is in a planar configuration while C5, which bears the other quinone oxygen, is tetrahedral, suggesting that the PQQ is in the semiquinone redox state. The substrate binding site has been identified close to PQQ and to the side chain of Asp297, the putative active site base. The proximity of the hydroxyl of methanol to C5 of PQQ compared to the greater separation of the substrate methyl group from C5 supports the addition-elimination reaction mechanism involving a hemiketal intermediate.     

Association of chromosome 12p genetic polymorphisms with lung adenocarcinoma risk and prognosis

The mapping near Kras2 of pulmonary adenoma susceptibility 1 (Pas1), a major locus affecting inherited predisposition to lung cancer in mice prompted us to test the homologous human region (12p12) for association with lung adenocarcinoma, by a population-based study. We genotyped 213 lung adenocarcinoma patients and 219 healthy blood donor subjects for five polymorphic markers mapping in the putative region of interest. Three marker polymorphisms, located in a region spanning approximately 700 kb, were significantly associated with lung adenocarcinoma risk. Furthermore, polymorphisms in KRAS2 and PTHLH loci were also associated with tumor prognosis. These results suggest the existence of a human Pas1 homologous locus on chromosome 12p12.     

Exploring the Gender Gap in Engineering: A Re‐Specification and Test of the Hypothesis of Cumulative Advantages and Disadvantages

Researchers using the hypothesis of cumulative advantages and disadvantages argue that the accumulation of small advantages for men and small disadvantages for women contributes to the gender gap in engineering. This paper uses data from a 1998 survey of engineering undergraduates to test a re‐specification of this hypothesis that treats the gender distribution of advantages and disadvantages as an empirical question. We considered four sets of factors that have been shown to promote choice of an engineering major, persistence in engineering, and progress in engineering: family background, high school participation in mathematics and science, university participation in engineering, and integration into engineering. We found gender differences for each set of factors. We also found that men and women accumulate different advantages and disadvantages as they move through the education pipeline. By demonstrating that the accumulation of advantages and disadvantages is gendered, these results highlight the importance of examining the impact of micro‐inequities on the persistence and progress of men and women in engineering.     

Intraoperative arthrography and the Ilizarov technique. Role in the correction of paediatric deformity and leg lengthening

We performed intraoperative arthrography of the knee in 12 children with congenital short femur, Blount's disease or Ollier's disease in whom the Ilizarov technique was used for correction of deformity, leg lengthening or both. In each case, arthrography revealed a joint surface considerably different from that assumed from plain radiographs, and resulted in a change in the placement of our reference wires before application of the frame. This gave significant improvement in the mechanical axis obtained at the time of removal of the frame. The technique is safe, cheap and easy to perform. It is a useful adjunct to the application of the Ilizarov frame when used for complex lengthening and correction of deformity in the leg.     

Efficient autoproteolytic processing of the MHV-A59 3C-like proteinase from the flanking hydrophobic domains requires membranes

The replicase gene of the coronavirus MHV-A59 encodes a serine-like proteinase similar to the 3C proteinases of picornaviruses. This proteinase domain is flanked on both sides by hydrophobic, potentially membrane-spanning, regions. Cell-free expression of a plasmid encoding only the 3C-like proteinase (3CLpro) resulted in the synthesis of a 29-kDa protein that was specifically recognized by an antibody directed against the carboxy-terminal region of the proteinase. A protein of identical mobility was detected in MHV-A59-infected cell lysates. In vitro expression of a plasmid encoding the 3CLpro and portions of the two flanking hydrophobic regions resulted in inefficient processing of the 29-kDa protein. However, the efficiency of this processing event was enhanced by the addition of canine pancreatic microsomes to the translation reaction, or removal of one of the flanking hydrophobic domains. Proteolysis was inhibited in the presence of N-ethylmaleimide (NEM) or by mutagenesis of the catalytic cysteine residue of the proteinase, indicating that the 3CLpro is responsible for its autoproteolytic cleavage from the flanking domains. Microsomal membranes were unable to enhance the trans processing of a precursor containing the inactive proteinase domain and both hydrophobic regions by a recombinant 3CLpro expressed from Escherichia coli. Membrane association assays demonstrated that the 29-kDa 3CLpro was present in the soluble fraction of the reticulocyte lysates, while polypeptides containing the hydrophobic domains associated with the membrane pelletes. With the help of a viral epitope tag, we identified a 22-kDa membrane-associated polypeptide as the proteolytic product containing the amino-terminal hydrophobic domain.     

Placental pathology and antiphospholipid antibodies: a descriptive study

We described placental pathology in antiphospholipid antibody (APL) syndrome, APL and no history of recurrent pregnancy loss, and in treated and untreated pregnancies of APL syndrome. Thirty-nine pregnancies of 28 patients were studied: 23 placentas delivered from 23 women with APL (13 with APL syndrome and 10 with serological APL); 8 untreated miscarriages before APL diagnosis from 6 of the 13 patients with APL syndrome and 1 of 10 with serological APL; and 8 miscarriages by 5 additional women before APL syndrome diagnosis. Histopathology was reviewed by a pathologist blinded except to gestational age. Contingency tables and analysis of variance (ANOVA) considered p < 0.05 significant. Comparing the placentas delivered at > 18 weeks' gestation, excessive perivillous coagulation, avascular terminal villi, and chronic villitis/uteroplacental vasculitis tended to be more common in treated APL syndrome than serological APL cases (p = 0.07). Of the 16 miscarriages before diagnosis of APL, 11 were lost at < 18 weeks' gestation. None had pathology typical of APL, but 4 of 11 (36%) had chronic intervillositis. Five of 16 miscarriages before the diagnosis of APL were miscarried between 18-22 weeks. Three of 5 (60%) miscarried after 18 weeks had multifocal uteroplacental thromboses, compared to 6 of 13 (46%) treated pregnancies with APL syndrome and 0 of 10 cases with serological APL.     

Oral mucositis with features of psoriasis: report of a case and review of the literature

There complete 18S ribosomal RNA gene sequences from the rumen ciliates, Entodinium caudatum (1,639 bp), Epidinium caudatum (1,638 bp), and Polyplastron multivesiculatum (1,640 bp) were determined and confirmed in the opposite direction. Trees produced using maximum parsimony and distance-matrix methods (least squares and neighbour-joining), with strong bootstrap support, depict the rumen ciliates as a monophyletic group. Entodinium caudatum is the earliest branching rumen ciliate. However, Entodinium simplex does not pair with En. caudatum, but rather with Polyplastron multivesiculatum. Signature sequences for these rumen ciliates reveal that the published SSrRNA gene sequence from En. simplex is in fact a Polyplastron species. The free-living haptorian ciliates, The Loxophyllum, Homalozoon and Spathidium (Subclass Haptoria), are monophyletic and are the sister group to the rumen ciliates. The litostomes (Class Litostomatea), consisting of the haptorians and the rumen ciliates, are also a monophyletic group.