178,145 research outputs found
Tragus berteronianus Schult., Mant.
No full textTragus berteronianus Schult., Mant. 2: 205 (1824). Distribution: Africa, Arabian Pen. to China Specimens: MOSHI Chekereni, Abdalla, R. 398 (NHT); Holili, Hemp, A. 1831 (NHT, UBT); Kisangiro, Peterson, P. 24190 (K); Moshi, Haarer, A.E. 39A (K); Moshi, Haarer, A.E. 737 (K); Sanya, Brooks, A.C. 24 (K).Published as part of Prunera-Olivé, Joan, Vorontsova, Maria S., Williams, Emma V., Mollel, Neduvoto P. & Hemp, Andreas, 2021, Checklist of Kilimanjaro grasses shows that both plot and herbarium methods are necessary to record diversity, pp. 201-244 in Phytotaxa 501 (2) on page 242, DOI: 10.11646/phytotaxa.501.2.1, http://zenodo.org/record/542481
X-ray crystal structure analysis of the catalytic domain of the oncogene product p21H-ras complexed with caged GTP and Mant dGppNHp
No full textThe X-ray structures of the 1:1 complexes formed between p21H-ras(residues 1 to 166) and the nucleotidesP3-1-(2-nitrophenyl)ethyl guanosine triphosphate (“caged GTP”; pure R- and S-diastereomers) and 3′-O-(N-methylanthraniloyl)-2′-deoxyguanosine 5′-β,γ-imido)-triphosphate (“mant dG-ppNHp”), have been refined to an R-factor of 21.4% (R-caged GTP, 1.85 Å resolution), 18.9% (S-caged GTP, 2.5 Å resolution) and 17.6% (mant dGppNHp, 2.7 Å resolution), respectively. Details of the structure determination, refinement and the structures themselves are presented. The overall structures of the complexes are identical in terms of the general organization of their secondary structure elements and are also identical to that reported for the analogous complex of p21H-raswith GppNHp. The binding of the GTP part is not significantly affected by the additional aromatic group (cage and mant, respectively) in contrast to the original observation on p21:caged GTP using the racemic mixture of R- and S-caged GTP. The main differences in the structures are observed in the region of loop L2 (residues Glu31 ato Thr35) where the additional aromatic group attached to the nucleotide comes very close to the side-chain of Tyr32, including backbone displacements of 2.6 Å, 2.2. Å and 0.3 Å for the residues from Glu31 to Thr35 for R-caged, S-caged GTP and mant dGppNHp, respectively. The refined structures provide additional data fro the design of new nucleotide analogs and the importance of their stereochemistry as well as for the design of new mutant forms of p21H-rasfor further biochemical investigations. The binding mode of mant dGppNHp reveals significant features for the understanding of the fluorescence signals observed in solution
Identification of an Arabidopsis inorganic pyrophosphatase capable of being imported into chloroplasts
No full textAn Arabidopsis cDNA coding for a previously uncharacterized isoform of inorganic pyrophosphatase was isolated. It was used to complement an E. coli mutant, demonstrating that it coded for an active enzyme. MgCl2 was necessary for the protein's activity, whilst NaF inhibited it. The Km for pyrophosphate and the pH optimum of the protein was determined. The gene coding for this protein was expressed in all tissues, and its expression in rosette leaves was induced by incubation on metabolizable sugars. In vitro import experiments demonstrated that the protein could be imported into chloroplasts and localized to the stromal compartment
Beyond a Fluorescent Probe: Inhibition of Cell Division Protein FtsZ by mant-GTP Elucidated by NMR and Biochemical Approaches
No full text© 2015 American Chemical Society. FtsZ is the organizer of cell division in most bacteria and a target in the quest for new antibiotics. FtsZ is a tubulin-like GTPase, in which the active site is completed at the interface with the next subunit in an assembled FtsZ filament. Fluorescent mant-GTP has been extensively used for competitive binding studies of nucleotide analogs and synthetic GTP-replacing inhibitors possessing antibacterial activity. However, its mode of binding and whether the mant tag interferes with FtsZ assembly function were unknown. Mant-GTP exists in equilibrium as a mixture of C2′- and C3′-substituted isomers. We have unraveled the molecular recognition process of mant-GTP by FtsZ monomers. Both isomers bind in the anti glycosidic bond conformation: 2′-mant-GTP in two ribose puckering conformations and 3′-mant-GTP in the preferred C2′ endo conformation. In each case, the mant tag strongly interacts with FtsZ at an extension of the GTP binding site, which is also supported by molecular dynamics simulations. Importantly, mant-GTP binding induces archaeal FtsZ polymerization into inactive curved filaments that cannot hydrolyze the nucleotide, rather than straight GTP-hydrolyzing assemblies, and also inhibits normal assembly of FtsZ from the Gram-negative bacterium Escherichia coli but is hydrolyzed by FtsZ from Gram-positive Bacillus subtilis. Thus, the specific interactions provided by the fluorescent mant tag indicate a new way to search for synthetic FtsZ inhibitors that selectively suppress the cell division of bacterial pathogens.BFU2011-23416 and BFU2014-51823-R (J.M.A), CTQ2012-32065 (J.J.B.), CM 2010/BMD-2353 (J.J.B. and J.M.A.), FCT SFRH/BPD/65462/2009 and UID/Multi/04378/2013 (F.M.) and a FPI fellowship (L.B.R.A).Peer Reviewe
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Letter from R. R. Zellick, Assistant Trust Officer, Anglo California National Bank of San Francisco, to Joseph R. Goodman, October 2, 1942
No full textLetter from R. R. Zellick, Assistant Trust Officer at The Anglo California National Bank of San Francisco, to Joseph R. Goodman, regarding property owned by Dave Tatsuno. Zellick mentions a dispute between current tenants and Tatsuno, and that Tatsuno has asked Goodman to help locate trustworthy tenants.Personal correspondence, organizational records, government documents, publications, and other papers created or collected by Joseph R. Goodman documenting the forced removal and incarceration of Japanese Americans during World War II, as well as organized resistance to incarceration. Included in the collection are records of the Japanese Young Men's Christian Association and the Japanese American Citizens' League in San Francisco, including papers of the Japanese YMCA's executive secretary Lincoln Kanai; Sakai family papers; Goodman's correspondence to and from Japanese American incarcerees, organizations opposing forced removal and incarceration of Japanese Americans, the War Relocation Authority, and others; publications, photographs, and ephemera from the Topaz Relocation Center, where Goodman taught high school; War Relocation Authority records and publications; and newspaper clippings, pamphlets, and reports about forced removal and incarceration created by various government, religious, and civic organizations, in California and nationwide
Serum carcinoembryonic antigen trends for diagnosing colorectal cancer recurrence in the FACS randomized clinical trial
No full textBackground: Most guidelines recommend that patients who have undergone curative resection for primary colorectal cancer are followed up for 5 years with regular blood carcinoembryonic antigen (CEA) tests to trigger further investigation for recurrence. However, CEA may miss recurrences, or patients may have false alarms and undergo unnecessary investigation. Methods: The diagnostic accuracy of trends in CEA measurements for recurrent colorectal cancer, taken as part of the FACS (Follow-up After Colorectal Surgery) trial (2003-2014), were analysed. Investigation to detect recurrence was triggered by clinical symptoms, scheduled CT or colonoscopy, or a CEA level of at least 7 μg/l above baseline. Time-dependent receiver operating characteristic (ROC) curve analysis was used to compare the diagnostic accuracy of CEA trends with single measurements. CEA trends were estimated using linear regression. Results: The area under the ROC curve (AUC) for CEA trend was at least 0·820 across all 5 years of follow-up. In comparison, the AUCs for single measurements ranged from 0·623 to 0·749. Improvement was most marked at the end of the first year of follow-up, with the AUC increasing from 0·623 (95 per cent c.i. 0·509 to 0·736) to 0·880 (0·814 to 0·947). However, no individual trend threshold achieved a sensitivity above 70 per cent (30 per cent missed recurrences). Conclusion: Interpreting trends in CEA measurements instead of single CEA test results improves diagnostic accuracy for recurrence, but not sufficiently to warrant it being used as a single surveillance strategy to trigger further investigation. In the absence of a more accurate biomarker, monitoring trends in CEA should be combined with clinical, endoscopic and imaging surveillance for improved accuracy.</p
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