Sialic Acid Glycobiology Unveils Trypanosoma cruzi Trypomastigote Membrane Physiology.

Trypanosoma cruzi, the flagellate protozoan agent of Chagas disease or American trypanosomiasis, is unable to synthesize sialic acids de novo. Mucins and trans-sialidase (TS) are substrate and enzyme, respectively, of the glycobiological system that scavenges sialic acid from the host in a crucial interplay for T. cruzi life cycle. The acquisition of the sialyl residue allows the parasite to avoid lysis by serum factors and to interact with the host cell. A major drawback to studying the sialylation kinetics and turnover of the trypomastigote glycoconjugates is the difficulty to identify and follow the recently acquired sialyl residues. To tackle this issue, we followed an unnatural sugar approach as bioorthogonal chemical reporters, where the use of azidosialyl residues allowed identifying the acquired sugar. Advanced microscopy techniques, together with biochemical methods, were used to study the trypomastigote membrane from its glycobiological perspective. Main sialyl acceptors were identified as mucins by biochemical procedures and protein markers. Together with determining their shedding and turnover rates, we also report that several membrane proteins, including TS and its substrates, both glycosylphosphatidylinositol-anchored proteins, are separately distributed on parasite surface and contained in different and highly stable membrane microdomains. Notably, labeling for α(1,3)Galactosyl residues only partially colocalize with sialylated mucins, indicating that two species of glycosylated mucins do exist, which are segregated at the parasite surface. Moreover, sialylated mucins were included in lipid-raft-domains, whereas TS molecules are not. The location of the surface-anchored TS resulted too far off as to be capable to sialylate mucins, a role played by the shed TS instead. Phosphatidylinositol-phospholipase-C activity is actually not present in trypomastigotes. Therefore, shedding of TS occurs via microvesicles instead of as a fully soluble form

Top Quarks as a Window to String Resonances

We study the discovery potential of string resonances decaying to $t\bar{t}$ final state at the LHC. We point out that top quark pair production is a promising and an advantageous channel for studying such resonances, due to their low Standard Model background and unique kinematics. We study the invariant mass distribution and angular dependence of the top pair production cross section via exchanges of string resonances. The mass ratios of these resonances and the unusual angular distribution may help identify their fundamental properties and distinguish them from other new physics. We find that string resonances for a string scale below 4 TeV can be detected via the $t\bar{t}$ channel, either from reconstructing the $t\bar{t}$ semi-leptonic decay or recent techniques in identifying highly boosted tops.Comment: 22 pages, 6 figure

The use of religious/spiritual coping among patients with cancer undergoing chemotherapy treatment

OBJECTIVE: to investigate the use of religious/spiritual coping among people with cancer undergoing chemotherapy. METHODS: a quantitative, descriptive and cross-sectional study of 101 patients undergoing intravenous chemotherapy in an oncology outpatients center in a public hospital in Minas Gerais, made in the first semester of 2011. For data collection, an interview was held, using a questionnaire for characterizing the sample and the Brief Spiritual/Religious Coping Scale. RESULTS: all subjects made use of religious/spiritual coping (mean=3.67; sd=0.37); the younger individuals, those with no religion and those who consider spiritual support unimportant tend to use coping negatively; individuals who would like to receive spiritual support and who participate in support groups for cancer patients, on the other hand, use coping positively. CONCLUSIONS: the study reinforces that religious/spiritual coping is an important strategy for coping with cancer, and contributes to an understanding of the same as a useful tool for spiritual care

Caucasian and Asian Specific Rheumatoid Arthritis Risk Loci Reveal Limited Replication and Apparent Allelic Heterogeneity in North Indians

Genome-wide association studies and meta-analysis indicate that several genes/loci are consistently associated with rheumatoid arthritis (RA) in European and Asian populations. To evaluate the transferability status of these findings to an ethnically diverse north Indian population, we performed a replication analysis. We investigated the association of 47 single-nucleotide polymorphisms (SNPs) at 43 of these genes/loci with RA in a north Indian cohort comprising 983 RA cases and 1007 age and gender matched controls. Genotyping was done using Infinium human 660w-quad. Association analysis by chi-square test implemented in plink was carried out in two steps. Firstly, association of the index or surrogate SNP (r2>0.8, calculated from reference GIH Hap-Map population) was tested. In the second step, evidence for allelic/locus heterogeneity at aforementioned genes/loci was assessed for by testing additional flanking SNPs in linkage equilibrium with index/surrogate marker

Determination of diquat by flow injection-chemiluminescence

A simple, economic, sensitive and rapid method for the determination of the pesticide diquat was described. This new method was based on the coupling of flow injection analysis methodology and direct chemiluminescent detection; to the authors' knowledge, this approach had not been used up to now with this pesticide. It was based on its oxidation with ferricyanide in alkaline medium; significant improvements in the analytical signal were achieved by using high temperatures and quinine as sensitiser. Its high throughput (144 h(-1)), together with its low limit of detection (2 ng mL(-1)), achieved without need of preconcentration steps, permitted the reliable quantification of diquat over the linear range of (0.01-0.6) mu g mL(-1) in samples from different origins (river, tap, mineral and ground waters), even in the presence of a 40-fold concentration of paraquat, a pesticide commonly present in the commercial formulations of diquat.López-Paz, JL.; Catalá-Icardo, M.; Antón Garrido, B. (2009). Determination of diquat by flow injection-chemiluminescence. Analytical and Bioanalytical Chemistry. 394(4):1073-1079. doi:10.1007/s00216-009-2609-zS107310793944Hayes WJ Jr, Laws ER Jr (1991) Handbook of pesticide toxicology, Academic Press, San DiegoUS Environmental Protection Agency. http://www.epa.gov/06WDW/contaminants/dw_contamfs/diquat.html (accessed in August 2008)Horwitz W (2000) Official methods of analysis of AOAC International 17th edition. AOAC International, Gaithersburg, MD, USAHara S, Sasaki N, Takase D, Shiotsuka S, Ogata K, Futagami K, Tamura K (2007) Anal Sci 23(5):523–531Rial Otero R, Cancho Grande B, Pérez Lamela C, Simal Gandara J, Aria Estevez M (2006) J Chromatogr Sci 44(9):539–542Aramendia MA, Borau V, Lafont F, Marinas JM, Moreno JM, Porras JM, Urbano FJ (2006) Food Chem 97(1):181–188Nuñez O, Moyano E, Galceran MT (2004) Anal Chim Acta 525(2):183–190Martinez Vidal JL, Belmonte Vega A, Sanchez Lopez FJ, Garrido Frenich AJ (2004) Chromatogr A 1050(2):179–184Lee XP, Kumazawa T, Fujishiro M, Hasegawa C, Arinobu T, Seno H, Sato K (2004) J Mass Spectrom 39(10):1147–1152De Almeida RM, Yonamine M (2007) J Chromatogr B 853(1–2):260–264De Souza D, Machado SAS (2006) Electroanalysis 18(9):862–872De Souza D, Da Silva MRC, Machado SAS (2006) Electroanalysis 18(23):2305–2313Picó Y, Rodriguez R, Manes J (2003) Trends Anal Chem 22(3):133–151Ishiwata T (2004) Bunseki Kagaku 53(8):863–864Carneiro MC, Puignou L, Galcerán MT (2000) Anal Chim Acta 408:263Luque M, Rios A, Valcarcel M (1998) Analyst 123(11):2383–2387Perez Ruiz T, Martínez Lozano C, Tomas V (1991) Int J Environ Anal Chem 44(4):243–252Perez Ruiz T, Martínez Lozano C, Tomas V (1991) Anal Chim Acta 244(1):99–104Townshend A (1990) Analyst 115:495–500López Paz JL, Catalá Icardo M (2008) Anal Chim Acta 625:173–179Pawlicová Z, Sahuquillo I, Catalá Icardo M, García Mateo JV, Martínez Calatayud J (2006) Anal Sci 22:29–34Albert García JR, Catalá Icardo M, Martínez Calatayud J (2006) Talanta 69:608–614Tomlin CDS (1997) The pesticide manual, 11th edn.The British Crop Protection CouncilUKCatalá-Icardo M, Martínez-Calatayud J (2008) Crit Rev Anal Chem 38:118–130Ministerio de Medio Ambiente y Medio Rural y Marino. http://www.marm.es/ (accessed in September 2008)US Environmental Protection Agency. http://www.epa.gov/OGWWDW/contaminants (accessed in October 2008