Substituted diaryl diselenides: Cytotoxic and apoptotic effect in human colon adenocarcinoma cells

AbstractAimsTo investigate the effects and study the underlying cell death mechanisms of diaryl diselenides, including: diphenyl diselenide (C6H5Se)2; 4-chlorodiphenyl diselenide (4-ClC6H4Se)2; 3-(trifluoromethyl)-diphenyl diselenide (3-CF3C6H4Se)2 and 4-methoxydiphenyl diselenide (4-MeOC6H4Se)2, on the human colon adenocarcinoma cell line HT-29.Main methodsThe viability of HT-29 cells after exposure to the diaryl diselenides and its substituted structures was based on the MTT assay. To verify if cell death was mediated throughout apoptosis mechanisms, flow cytometry and real-time PCR (qPCR) analyses were conducted.Key findingsThe MTT assay and flow cytometry analyses showed that (3-CF3C6H4Se)2 and (4-MeOC6H4Se)2 induced cytotoxicity through apoptosis mechanisms in HT-29 cells. qPCR revealed there was an up-regulation of pro-apoptotic (Bax, casapase-9, caspase-8, apoptosis-inducing factor (AIF) and Endonuclease G (EndoG)) and cell-cycle arrest genes (p53 and p21) and down-regulation of anti-apoptotic (Bcl-2 and survivin) and Myc genes.SignificanceThese results demonstrate that (3-CF3C6H4Se)₂ and (4-MeOC6H4Se)2 have the potential to induce apoptosis in HT-29 cells through the activation of caspase-dependent and independent pathways and through cell-cycle arrest

Characterization of the immunogenic and antigenic potential of putative lipoproteins from Leptospira interrogans

The search for a vaccine capable of conferring heterologous protection, through the identification of conserved and cross-protective antigens, remains an ongoing priority in leptospirosis research. In the present study, an in silico analysis was used to identify potentially protective lipoproteins from Leptospira interrogans serovar Copenhageni. Eight putative lipoproteins were selected (LIC10009, LIC10054, LIC10091, LIC11058, LIC11567, LIC13059, LIC13305, and LIC20172), cloned and expressed in Escherichia coli and purified by affinity chromatography. The recombinant proteins were used to inoculate mice and the subsequent humoral immune response was evaluated by ELISA. Seven of the potential lipoproteins induced a significant IgG response. Furthermore, all of the recombinant proteins were recognized by antibodies present in the sera of severe leptospirosis patients. These putative lipoproteins exhibited potential for further evaluation as prospective vaccine candidates

Bioinformatics describes novel Loci for high resolution discrimination of leptospira isolates

Background: Leptospirosis is one of the most widespread zoonoses in the world and with over 260 pathogenic serovars there is an urgent need for a molecular system of classification. The development of multilocus sequence typing (MLST) schemes for Leptospira spp. is addressing this issue. The aim of this study was to identify loci with potential to enhance Leptospira strain discrimination by sequencing-based methods.\ud \ud Methodology and Principal Findings: We used bioinformatics to evaluate pre-existing loci with the potential to increase the discrimination of outbreak strains. Previously deposited sequence data were evaluated by phylogenetic analyses using either single or concatenated sequences. We identified and evaluated the applicability of the ligB, secY, rpoB and lipL41 loci, individually and in combination, to discriminate between 38 pathogenic Leptospira strains and to cluster them according to the species they belonged to. Pairwise identity among the loci ranged from 82.0-92.0%, while interspecies identity was 97.7-98.5%. Using the ligB-secY-rpoB-lipL41 superlocus it was possible to discriminate 34/38 strains, which belong to six pathogenic Leptospira species. In addition, the sequences were concatenated with the superloci from 16 sequence types from a previous MLST scheme employed to study the association of a leptospiral clone with an outbreak of human leptospirosis in Thailand. Their use enhanced the discriminative power of the existing scheme. The lipL41 and rpoB loci raised the resolution from 81.0-100%, but the enhanced scheme still remains limited to the L. interrogans and L. kirschneri species.\ud \ud Conclusions: As the first aim of our study, the ligB-secY-rpoB-lipL41 superlocus demonstrated a satisfactory level of discrimination among the strains evaluated. Second, the inclusion of the rpoB and lipL41 loci to a MLST scheme provided high resolution for discrimination of strains within L. interrogans and L. kirschneri and might be useful in future epidemiological studies

Lithospheric evolution in the wake of the Mendocino Triple Junction: structure of the San Andreas Fault system at 2 Ma

As the Mendocino triple junction (MTJ) moves northwards up the North American margin, the tectonic regime changes from subduction to strike-slip. For the first few million years following triple junction migration, the San Andreas Fault system consists of several strike-slip faults distributing deformation over a region ~ 150 km wide. This same region is expected to be affected by a slab gap beneath North America, created by the northward removal of the subducting Gorda plate, and into which asthenospheric mantle is thought to rise to crustal depths. The onshore and offshore Mendocino Triple Junction Seismic Experiment (MTJSE) provides a continuous seismic velocity-reflectivity cross-section across the deforming zone from the Pacific ocean basin to the eastern edge of the California Coast Ranges. The accretionary complex rocks that make up most of the crustal thickness are underlain by a 5-10 km thick high-velocity(6.4-7.2 km s- 1) layer at the base of the crust that extends from the Pacific to at least 50 km, and probably 90 km east of the San Andreas Fault. The top of the lower crustal layer deepens from 7 km beneath the Pacific ocean basin at the west end of the profile to 23 km at the east end by a gentle (5° -10°) eastward dip punctuated by abrupt offsets at the San Andreas and Maacama fault zones. At each fault the top of the lower crust is offset by up to 4 km, down to the east. The Moho is similarly deformed beneath the faults, although by only 2 km. Such localized deformation of the Moho implies that these two strike-slip faults penetrate through the entire crust to the upper mantle. Good agreement between seismic velocity and seismic reflectivity in the vicinity of the faults gives confidence in these results, although details of the offset beneath the San Andreas Fault are better resolved than those under the Maacama Fault. Seismic velocities in the upper mantle show only a small change along the profile, from 8.1 km s- 1 beneath the Pacific to about 7.9 km s- 1 beneath the Coast Ranges. We infer that upwelling of asthenosphere into the slab gap is limited laterally, or a lithospheric lid is present in the slab gap by 2 Ma. Gravity data and crustal density structure show that most of the margin width is in local Airy isostasy with the changes in crustal thickness near the strike-slip faults corresponding closely to changes in surface topography. The crustal blocks defined by the strike-slip faults appear to be independently in isostatic equilibrium, provided that the mantle beneath the Coast Ranges has a somewhat lower density than that beneath the Pacific plate. The densities in the Coast Range upper mantle are consistent with limited temperature elevation, suggesting that the asthenospheric mantle is present beneath the depth of seismic energy penetration from our survey