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81.
Andy F.S. Taylor Alan E. Hills Giampaolo Simonini Ernst E. Both Ursula Eberhardt 《Mycological Research》2006,110(3):276-287
Identification of species within the boletoid genus Xerocomus has relied heavily upon the macromorphological features of the basidiomes. However, the phenotypic plasticity of these features has resulted in considerable confusion over the delimitation of taxa. In this study, we examined collections attributed to the X. subtomentosus complex in Europe using morphological and rDNA–ITS sequence data. In total, 45 European collections from a wide range of geographical areas and ecological conditions were included in the study. In spite of detecting considerable genetic variation, even within individual basidiomes of X. subtomentosus, molecular data, spore size, flesh colour, and the colour of the basal mycelium allow for the recognition of four distinct taxa: two correspond to X. subtomentosus (13 collections) and X. ferrugineus (20); one X. chrysonemus sp. nov. (10), to date only found in the UK, is described as new; and the existence of another taxon (two; Italy and UK) is noted but left undescribed owing to lack of material. Eight collections from North America were also included in the study, from which two taxa with a close affinity to X. ferrugineus were recognised. 相似文献
82.
Sergio Luiz Montego Ferreira Junior Elis Regina Dalla Costa Paula Gon?alves dos Santos Harrison Magdinier Gomes Marcia Susana Nunes Silva Leonardo Souza Esteves Martha Maria Oliveira Raquel de Abreu Maschmann Afranio Lineu Kritski Philip Noel Suffys Maria Lucia Rosa Rossetti 《Memórias do Instituto Oswaldo Cruz》2014,109(3):307-314
Drug-resistant tuberculosis (TB) threatens global TB control and is a major public
health concern in several countries. We therefore developed a multiplex assay
(LINE-TB/MDR) that is able to identify the most frequent mutations related to
rifampicin (RMP) and isoniazid (INH) resistance. The assay is based on multiplex
polymerase chain reaction, membrane hybridisation and colorimetric detection
targeting of rpoB and katG genes, as well as the
inhA promoter, which are all known to carry specific mutations
associated with multidrug-resistant TB (MDR-TB). The assay was validated on a
reference panel of 108 M. tuberculosis isolates that were characterised by the
proportion method and by DNA sequencing of the targets. When comparing the
performance of LINE-TB/MDR with DNA sequencing, the sensitivity, specificity and
agreement were 100%, 100% and 100%, respectively, for RMP and 77.6%, 90.6% and 88.9%,
respectively, for INH. Using drug sensibility testing as a reference standard, the
performance of LINE-TB/MDR regarding sensitivity, specificity and agreement was 100%,
100% and 100% (95%), respectively, for RMP and 77%, 100% and 88.7% (82.2-95.1),
respectively, for INH. LINE-TB/MDR was compared with GenoType MTBDRplus for 65
isolates, resulting in an agreement of 93.6% (86.7-97.5) for RIF and 87.4%
(84.3-96.2) for INH. LINE-TB/MDR warrants further clinical validation and may be an
affordable alternative for MDR-TB diagnosis. 相似文献
83.
84.
The first 17 amino acids of Huntingtin protein (N17) play a crucial role in the protein's aggregation. Here we predict its free energy landscape in aqueous solution by using bias exchange metadynamics. All our findings are consistent with experimental data. N17 populates four main kinetic basins, which interconvert on the microsecond time-scale. The most populated basin (about 75%) is a random coil, with an extended flat exposed hydrophobic surface. This might create a hydrophobic seed promoting Huntingtin aggregation. The other main populated basins contain helical conformations, which could facilitate N17 binding on its cellular targets. 相似文献
85.
Carvalho WA Ianella P Arnoldi FG Caetano AR Maruyama SR Ferreira BR Conti LH da Silva MR Paula JO Maia AA Santos IK 《Immunogenetics》2011,63(5):319-324
Bovines present contrasting, heritable phenotypes of infestations with the cattle tick, Rhipicephalus (Boophilus) microplus. Tick salivary glands produce IgG-binding proteins (IGBPs) as a mechanism for escaping from host antibodies that these ectoparasites ingest during blood meals. Allotypes that occur in the constant region of IgG may differ in their capacity to bind with tick IGBPs; this may be reflected by the distribution of distinct allotypes according to phenotypes of tick infestations. In order to test this hypothesis, we investigated the frequency of haplotypes of bovine IgG2 among tick-resistant and tick-susceptible breeds of bovines. Sequencing of the gene coding for the heavy chain of IgG2 from 114 tick-resistant (Bos taurus indicus, Nelore breed) and tick-susceptible (B. t. taurus, Holstein breed) bovines revealed SNPs that generated 13 different haplotypes, of which 11 were novel and 5 were exclusive of Holstein and 3 of Nelore breeds. Alignment and modeling of coded haplotypes for hinge regions of the bovine IgG2 showed that they differ in the distribution of polar and hydrophobic amino acids and in shape according to the distribution of these amino acids. We also found that there was an association between genotypes of the constant region of the IgG2 heavy chain with phenotypes of tick infestations. These findings open the possibility of investigating if certain IgG allotypes hinder the function of tick IGBPs. If so, they may be markers for breeding for resistance against tick infestations. 相似文献
86.
A fundamental understanding of the mechanical properties of the extracellular matrix (ECM) is critically important to quantify the amount of macroscopic stress and/or strain transmitted to the cellular level of vascular tissue. Structural constitutive models integrate histological and mechanical information, and hence, allocate stress and strain to the different microstructural components of the vascular wall. The present work proposes a novel multi-scale structural constitutive model of passive vascular tissue, where collagen fibers are assembled by proteoglycan (PG) cross-linked collagen fibrils and reinforce an otherwise isotropic matrix material. Multiplicative kinematics account for the straightening and stretching of collagen fibrils, and an orientation density function captures the spatial organization of collagen fibers in the tissue. Mechanical and structural assumptions at the collagen fibril level define a piece-wise analytical stress-stretch response of collagen fibers, which in turn is integrated over the unit sphere to constitute the tissue's macroscopic mechanical properties. The proposed model displays the salient macroscopic features of vascular tissue, and employs the material and structural parameters of clear physical meaning. Likewise, the constitutive concept renders a highly efficient multi-scale structural approach that allows for the numerical analysis at the organ level. Model parameters were estimated from isotropic mean-population data of the normal and aneurysmatic aortic wall and used to predict in-vivo stress states of patient-specific vascular geometries, thought to demonstrate the robustness of the particular Finite Element (FE) implementation. The collagen fibril level of the multi-scale constitutive formulation provided an interface to integrate vascular wall biology and to account for collagen turnover. 相似文献
87.
Rossetti G Cong X Caliandro R Legname G Carloni P 《Journal of molecular biology》2011,411(3):700-1431
Human (Hu) familial prion diseases are associated with about 40 point mutations of the gene coding for the prion protein (PrP). Most of the variants associated with these mutations are located in the globular domain of the protein. We performed 50 ns of molecular dynamics for each of these mutants to investigate their structure in aqueous solution. Overall, 1.6 μs of molecular dynamics data is presented. The calculations are based on the AMBER(parm99) force field, which has been shown to reproduce very accurately the structural features of the HuPrP wild type and a few variants for which experimental structural information is available. The variants present structural determinants different from those of wild-type HuPrP and the protective mutation HuPrP(E219K-129M). These include the loss of salt bridges in α2-α3 regions and the loss of π-stacking interactions in the β2-α2 loop. In addition, in the majority of the mutants, the α3 helix is more flexible and Y169 is more solvent exposed. The presence of similar traits in this large spectrum of mutations hints to a role of these fingerprints in their known disease-causing properties. Overall, the regions most affected by disease-linked mutations in terms of structure and/or flexibility are those involved in the pathogenic conversion to the scrapie form of the protein and in the interaction with cellular partners. These regions thus emerge as optimal targets for antibody- and ligand-binding studies. 相似文献
88.
Eunice Teresinha Giampaolo Janaina Habib Jorge Ana Lúcia Machado Ana Cláudia Pavarina Carlos Eduardo Vergani 《Gerodontology》2011,28(2):121-126
doi:10.1111/j.1741‐2358.2009.00332.x Effect of thermal cycling on microleakage between hard chairside relines and denture base acrylic resins Objectives: Microleakage is a pre‐stage of debonding between hard chairside relines and denture base acrylic resins. Therefore, it is important to assess them with regard to the longevity of the relined denture. This study investigated the effect of thermal cycling on the microleakage at the interface of three hard chairside reline resins and three denture base resins. Material and methods: Rectangular bars (12 mm × 3 mm × 3 mm) of Lucitone 550, Acron MC and QC 20 were made and relined with Kooliner, Tokuyama Rebase Fast II and Ufi Gel Hard, Lucitone 550, Acron MC and QC 20 resins. Specimens were divided into one control and two test groups (n = 10). In specimens of the control group, the microleakage was performed after the reline procedure. In Test Group 1, the specimens were stored for 24 h in distilled water at room temperature and in Test Group 2; the specimens were thermal cycled from 5 to 55°C for 5000 cycles with a 30‐s dwell time. Subsequently, all specimens were immersed in 50% silver nitrate solutions for 24 h. All specimens were sectioned longitudinally into three fractions and the lateral sections were examined (n = 20). Silver nitrate stain penetration was examined under a stereoscopic lens with ×30 magnification, and the images were captured. Leica Qwin image analysis software was used to determine microleakage at the interface of the materials. Data were analysed using the Kruskal–Wallis test at a 95% level of significance. Results: For all cycles, there were no statistically significant differences between thermal cycled and non‐thermal cycled groups (p > 0.05). Conclusion: It can be concluded that thermal cycling had no effect on the microleakage. 相似文献
89.
Da Settimo F Primofiore G La Motta C Salerno S Novellino E Greco G Lavecchia A Laneri S Boldrini E 《Bioorganic & medicinal chemistry》2005,13(2):491-499
The 2,3-dihydrospiro[4H-thiopyrano[2,3-b]pyridin-4,4'-imidazolidine]-2',5'-dione 3 and its 7-methyl analogue 4 were synthesized and tested for their ability to inhibit aldose reductase (ALR2). To expand the structure-activity relationships, the sulfone 5 and the acetic acid derivative 7 were also prepared and tested. Compounds 3 and 4 proved to be potent ALR2 inhibitors, with IC50 values in the submicromolar range (0.96 and 0.94 microM, respectively) similar to that of sorbinil (0.65 microM). Moreover, compound 3 was found to be highly potent in preventing cataract development in severely galactosemic rats, like tolrestat, when administered as an eyedrop solution. Docking simulations of both R- and S-isomers of 3 into the ALR2 crystal structure were carried out to guide, prospectively, the design of new analogues. 相似文献
90.