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51.
Raquel López‐Antoñanzas Lawrence J. Flynn Fabien Knoll 《Cladistics : the international journal of the Willi Hennig Society》2013,29(3):247-273
The subfamily Rhizomyinae is known from the Late Oligocene up to the present. Today this group comprises six species, which live in southern Asia and eastern Africa. Despite the current moderate diversity of the rhizomyines, they had a greater diversification and wider distribution in the past: from Asia, their land of origin, to Africa, which they entered during the Early Miocene. So far 33 fossil species can be referred to this group. A cladistic analysis involving fossil and living species has been carried out. Prokanisamys spp. turned out to be the most basal taxa of the ingroup. This analysis calls into question the monophyly of several genera, and allows the proposal of a phylogenetic definition of the tribes Tachyoryctini and Rhizomyini. It also provides information about the origin of the African rhizomyines and allows inferring multiple dispersal phenomena from Asia to Africa in Early and Late Miocene times. 相似文献
52.
Raquel Fonseca-Maldonado Davi Serradella Vieira Juliana Sanchez Alponti Eric Bonneil Pierre Thibault Richard John Ward 《The Journal of biological chemistry》2013,288(35):25522-25534
Protein glycosylation is a common post-translational modification, the effect of which on protein conformational and stability is incompletely understood. Here we have investigated the effects of glycosylation on the thermostability of Bacillus subtilis xylanase A (XynA) expressed in Pichia pastoris. Intact mass analysis of the heterologous wild-type XynA revealed two, three, or four Hex8–16GlcNAc2 modifications involving asparagine residues at positions 20, 25, 141, and 181. Molecular dynamics (MD) simulations of the XynA modified with various combinations of branched Hex9GlcNAc2 at these positions indicated a significant contribution from protein-glycan interactions to the overall energy of the glycoproteins. The effect of glycan content and glycosylation position on protein stability was evaluated by combinatorial mutagenesis of all six potential N-glycosylation sites. The majority of glycosylated enzymes expressed in P. pastoris presented increased thermostability in comparison with their unglycosylated counterparts expressed in Escherichia coli. Steric effects of multiple glycosylation events were apparent, and glycosylation position rather than the number of glycosylation events determined increases in thermostability. The MD simulations also indicated that clustered glycan chains tended to favor less stabilizing glycan-glycan interactions, whereas more dispersed glycosylation patterns favored stabilizing protein-glycan interactions. 相似文献
53.
Roberto Zenteno-Cuevas Francisco X Silva-Hernández Fabiola Mendoza-Damián Maria Dolores Ramírez-Hernández Karen Vázquez-Medina Lorena Widrobo-García Aremy Cuellar-Sanchez Raquel Mu?íz-Salazar Leonor Enciso-Moreno Lucia Monserrat Pérez-Navarro José Antonio Enciso-Moreno 《Memórias do Instituto Oswaldo Cruz》2013,108(6):718-723
Tuberculosis (TB) is an infectocontagious respiratory disease caused by members
of the Mycobacterium tuberculosis complex. A 7 base pair (bp)
deletion in the locus polyketide synthase
(pks)15/1 is described as polymorphic among members of the
M. tuberculosis complex, enabling the identification of
Euro-American, Indo-Oceanic and Asian lineages. The aim of this study was to
characterise this locus in TB isolates from Mexico. One hundred
twenty clinical isolates were recovered from the states of Veracruz and Estado
de Mexico. We determined the nucleotide sequence of a ± 400 bp fragment of the
locus pks15/1, while genotypic characterisation was
performed by spoligotyping. One hundred and fifty isolates contained the 7 bp
deletion, while five had the wild type locus. Lineages X (22%),
LAM (18%) and T (17%) were the most frequent; only three (2%) of the isolates
were identified as Beijing and two (1%) EAI-Manila. The wild type
pks15/1 locus was observed in all Asian lineage isolates
tested. Our results confirm the utility of locus pks15/1 as a
molecular marker for identifying Asian lineages of the M.
tuberculosis complex. This marker could be of great value in the
epidemiological surveillance of TB, especially in countries like Mexico, where
the prevalence of such lineages is unknown. 相似文献
54.
Gabriel Capella Machado Daniela Vanessa Moris Thales Domingos Arantes Luciane Regina Franciscone Silva Raquel Cordeiro Theodoro Rinaldo P?ncio Mendes Adriana Pardini Vicentini Eduardo Bagagli 《Memórias do Instituto Oswaldo Cruz》2013,108(5):637-643
We aimed to evaluate whether the occurrence of cryptic species of
Paracoccidioides brasiliensis, S1, PS2, PS3 and
Paracoccidioides lutzii, has implications in the
immunodiagnosis of paracoccidioidomycosis (PCM). Small quantities of the antigen
gp43 were found in culture filtrates of P. lutzii strains and
this molecule appeared to be more variable within P. lutzii
because the synonymous-nonsynonymous mutation rate was lower, indicating an
evolutionary process different from that of the remaining genotypes. The
production of gp43 also varied between isolates belonging to the same species,
indicating that speciation events are important, but not sufficient to fully
explain the diversity in the production of this antigen. The culture filtrate
antigen AgEpm83, which was obtained from a PS3 isolate, showed large quantities
of gp43 and reactivity by immunodiffusion assays, similar to the standard
antigen (AgB-339) from an S1 isolate. Furthermore, AgEpm83 was capable of
serologically differentiating five serum samples from patients from the Botucatu
and Jundiaí regions. These patients had confirmed PCM but, were non-reactive to
the standard antigen, thus demonstrating an alternative for serological
diagnosis in regions in which S1 and PS2 occur. We also emphasise that it is not
advisable to use a single antigen preparation to diagnose PCM, a disease that is
caused by highly diverse pathogens. 相似文献
55.
Raquel Lebrero Elisa Rodríguez Rebeca Pérez Pedro A. García-Encina Raúl Muñoz 《Applied microbiology and biotechnology》2013,97(10):4627-4638
The removal of hydrophobic volatile organic compounds (VOCs) still remains the main restriction in the biological treatment of odorous emissions due to mass transfer limitations. The addition of a non-aqueous phase to conventional biotrickling filters (BTF) may overcome this limitation by enhancing VOCs transport from the gas to the microorganisms. This study compared the long-term and transient performance of a one- (1P) and two-liquid phase (2P; with silicone oil as non-aqueous phase) BTFs for the removal of four VOCs (butanone, toluene, alpha-pinene, and hexane) at empty bed residence times (EBRT) ranging from 47 to 6 s. Removal efficiencies (RE) >96 % were obtained for butanone, toluene, and alpha-pinene in both bioreactors regardless of the EBRT, while higher hexane REs were recorded in the 2P-BTF (81–92 %) compared to the 1P-BTF (60–97 %). The two-phase system always showed a more consistent performance, being able to better withstand step VOC concentration increases and starvation periods, although it was more affected by liquid recycling shutdowns due to a reduced VOC mass transfer. The analysis of the microbial communities showed a high biodiversity and richness despite the low C source spectrum and high community evenness and richness. In this context, the presence of silicone oil mediated the development of a highly different phylogenetic composition of the communities. 相似文献
56.
Dr Raquel Marin Cristina M. Ramírez Cristina M. Ramírez Miriam González Elena González-Muñoz 《Molecular membrane biology》2013,30(2):148-160
Voltage-dependent anion channel (VDAC) is a porin known by its role in metabolite transport across mitochondria and participation in apoptotic processes. Although traditionally accepted to be located within mitochondrial outer membrane, some data has also reported its presence at the plasma membrane level where it seems to participate in regulation of normal redox homeostasis and apoptosis. Here, exposure of septal SN56 and hippocampal HT22 cells to specific anti-VDAC antibodies prior to amyloid beta (Aβ) peptide was observed to prevent neurotoxicity. In these cell lines, we identified a VDAC form associated with the plasma membrane that seems to be particularly abundant in caveolae. The two membrane-related isoforms of estrogen receptor α (mERα) (80 and 67 kDa), known in SN56 cells to participate in estrogen-induced neuroprotection against Aβ injury, were also observed to be present in caveolae. Interestingly, we demonstrated for the first time that both VDAC and mERα interact at the plasma membrane of these neurons as well as in microsomal fractions of the corresponding murine septal and hippocampal tissues. These proteins were also shown to associate with caveolin-1, thereby corroborating their presence in caveolar microdomains. Taken together, these results suggest that VDAC-mERα association at the plasma membrane level may participate in the modulation of Aβ-induced cell death. 相似文献
57.
Carlos M.G. Azevedo Carlos M.M. Afonso Diana Sousa Raquel T. Lima M. Helena Vasconcelos Madalena Pedro João Barbosa Arlene G. Corrêa Salette Reis Madalena M.M. Pinto 《Bioorganic & medicinal chemistry》2013,21(11):2941-2959
A promising antitumor xanthone derivative was optimized following a multidimensional approach that involved the synthesis of 17 analogues, the study of their lipophilicity and solubility, and the evaluation of their growth inhibitory activity on four human tumor cell lines. A new synthetic route for the hit xanthone derivative was also developed and applied for the synthesis of its analogues. Among the used cell lines, the HL-60 showed to be in general more sensitive to the compounds tested, with the most potent compound having a GI50 of 5.1 μM, lower than the hit compound. Lipophilicity was evaluated by the partition coefficient (Kp) of a solute between buffer and two membrane models, namely liposomes and micelles. The compounds showed a log Kp between 3 and 5 and the two membrane models showed a good correlation (r2 = 0.916) between each other. Studies concerning relationship between solubility and structure were developed for the hit compound and 5 of its analogues. 相似文献
58.
59.
Raquel M. Walton Thomas Parmentier John H. Wolfe 《Histochemistry and cell biology》2013,139(3):415-429
Identification of neural stem and progenitor cells (NPCs) in vitro and in vivo is essential to the use of developmental and disease models of neurogenesis. The dog is a valuable large animal model for multiple neurodegenerative diseases and is more closely matched to humans than rodents with respect to brain organization and complexity. It is therefore important to determine whether immunohistochemical markers associated with NPCs in humans and rodents are also appropriate for the dog. The NPC markers CD15, CD133, nestin, GFAP and phosphacan (DSD-1) were evaluated in situ in the canine rostral telencephalon, hippocampal dentate gyrus, and cerebellum at different postnatal time-points. Positive staining results were interpreted in the context of region and cellular morphology. Our results showed that neurospheres and cells within the rostral subventricular zone (SVZ), dentate gyrus subgranular zone (SGZ), and white matter tracts of the cerebellum were immunopositive for CD15, nestin and GFAP. Neurospheres and the cerebellum were immunonegative for CD133, whereas CD133 staining was present in the postnatal rostral SVZ. Anti-phosphacan antibody staining delineated the neurogenic niches of the rostral lateral ventricle SVZ and the hippocampal SGZ. Positive staining for phosphacan was also noted in white matter tracts of the cerebellum and within the Purkinje layer. Our results showed that in the dog these markers were associated with regions shown to be neurogenic in rodents and primates. 相似文献
60.
Maricy Raquel Lindenbah Bonfá Matthew James Grossman Francine Piubeli Encarnación Mellado Lucia Regina Durrant 《Biodegradation》2013,24(5):699-709
Phenol is a toxic aromatic compound used or produced in many industries and as a result a common component of industrial wastewaters. Phenol containing waste streams are frequently hypersaline and therefore require halophilic microorganisms for efficient biotreatment without dilution. In this study three halophilic bacteria isolated from different saline environments and identified as Halomonas organivorans, Arhodomonas aquaeolei and Modicisalibacter tunisiensis were shown to be able to grow on phenol in hypersaline media containing 100 g/L of total salts at a concentration of 3 mM (280 mg/L), well above the concentration found in most waste streams. Genes encoding the aromatic dioxygenase enzymes catechol 1,2 dioxygenase and protocatechuate 3,4-dioxygenase were present in all strains as determined by PCR amplification using primers specific for highly conserved regions of the genes. The gene for protocatechuate 3,4-dioxygenase was cloned from the isolated H. organivorans and the translated protein was evaluated by comparative protein sequence analysis with protocatechuate 3,4-dioxygenase proteins from other microorganisms. Although the analysis revealed a wide range of sequence divergence among the protocatechuate 3,4-dioxygenase family, all of the conserved domain amino acid structures identified for this enzyme family are identical or conservatively substituted in the H. organivorans enzyme. 相似文献