Coxiella burnetii infection in C57BL/6 mice aged 1 or 14 months

The objective of this study was to investigate the effects of age on infection with Coxiella burnetii, the agent of Q fever. Bacterial burden and granuloma number were increased in the spleens of 14-month-old as compared with 1-month-old mice. This increase was not the result of an anti-inflammatory macrophage response, because inflammatory and anti-inflammatory cytokines were induced in macrophages from young mice but were repressed in mature mice. In addition, macrophage microbicidal competence was similar in mature and young mice. These results suggest the importance of individual host factors in the pathophysiology of an infectious disease such as Q fever.     

Improving model construction of profile HMMs for remote homology detection through structural alignment

Background  

Remote homology detection is a challenging problem in Bioinformatics. Arguably, profile Hidden Markov Models (pHMMs) are one of the most successful approaches in addressing this important problem. pHMM packages present a relatively small computational cost, and perform particularly well at recognizing remote homologies. This raises the question of whether structural alignments could impact the performance of pHMMs trained from proteins in the Twilight Zone, as structural alignments are often more accurate than sequence alignments at identifying motifs and functional residues. Next, we assess the impact of using structural alignments in pHMM performance.     

Clinical and radiologic rebound after discontinuation of natalizumab therapy in a highly active multiple sclerosis patient was not halted by dimethyl-fumarate: a case report

Background

The evidence on the use of the oral dimethyl-fumarate after the discontinuation of treatment with natalizumab in people with Multiple Sclerosis is still little. Natalizumab discontinuation may induce the recurrence or rebound of the clinical and neuroradiological disease activity. Currently no therapeutic approach has been established to abolish disease reactivation and rebound after natalizumab interruption.

Case Presentation

We describe a case of a 21-year-old woman affected from a highly active relapsing-remitting Multiple Sclerosis who developed a clinical and radiological rebound 5 months after the last infusion of natalizumab, while she was being treated with dimethyl-fumarate 240 mg twice daily. She had received a bridge “therapy” with Cyclophosphamide before staring dimethyl-fumarate.

Conclusion

We report on this case to stimulate further research to establish whether new current and future drugs available for multiple sclerosis are able to halt the disease rebound after the natalizumab interruption.

     

Comparison of the binding behavior of several histidine-containing proteins with immobilized copper(II) complexes of 1,4,7-triazacyclononane and 1,4-bis(1,4,7-triazacyclononan-1-yl)butane

The protein binding characteristics of the immobilized binucleating chelate system, 1,4-bis(1,4,7-triazacyclononan-1-yl)butane (tacn(2)butane), complexed with Cu(2+) ions have been investigated with hen egg white lysozyme, horse skeletal muscle myoglobin and horse heart cytochrome C, as well as three histidine-rich proteins, serum albumin, transferrin, and α(2)-macroglobulin, present in partially fractionated human serum. The effects of pH, ionic strength and elution buffers on protein binding have been examined and compared with those of the analogous immobilized mononuclear copper complex of 1,4,7-triazacyclononane (tacn). The Cu(2+)-tacn(2)butane system was generally found to exhibit higher protein binding affinities than the Cu(2+)-tacn system, suggesting that the presence of immobilized binuclear copper(II) species leads to enhanced coordinative interaction with surface-exposed amino acid residues of the studied proteins. However, under some buffer conditions the dependencies of protein binding and elution on pH and ionic strength with these immobilized metal ion affinity chromatographic (IMAC) systems were consistent with electrostatic, hydrophobic and π-bonding interactions playing a significant secondary role in addition to the dominant coordinative interactions. As such, the results indicated that the selectivities were not solely dependent on the histidine content of the protein. In accord with this conclusion, differences in the selectivities of the Cu(2+)-tacn and Cu(2+)-tacn(2)butane adsorbents for serum albumin, transferrin, and α(2)-macroglobulin were observed depending on the choice of elution buffer. This attribute suggests that additional selectivity features can be realised for the separation of specific proteins with this new class of adsorbent.     

Does HAART Efficacy Translate to Effectiveness? Evidence for a Trial Effect

Background

Patients who participate in clinical trials may experience better clinical outcomes than patients who initiate similar therapy within clinical care (trial effect), but no published studies have evaluated a trial effect in HIV clinical trials.

Methods

To examine a trial effect we compared virologic suppression (VS) among patients who initiated HAART in a clinical trial versus in routine clinical care. VS was defined as a plasma HIV RNA ≤400 copies/ml at six months after HAART initiation and was assessed within strata of early (1996–99) or current (2000–06) HAART periods. Risk ratios (RR) were estimated using binomial models.

Results

Of 738 persons initiating HAART, 30.6% were women, 61.7% were black, 30% initiated therapy in a clinical trial and 67% (n = 496) had an evaluable six month HIV RNA result. HAART regimens differed between the early and current periods (p<0.001); unboosted PI regimens (55.6%) were more common in the early and NNRTI regimens (46.4%) were more common in the current period. Overall, 78% (95%CI 74, 82%) of patients achieved VS and trial participants were 16% more likely to achieve VS (unadjusted RR 1.16, 95%CI 1.06, 1.27). Comparing trial to non-trial participants, VS differed by study period. In the early period, trial participants initiating HAART were significantly more likely to achieve VS than non-trial participants (adjusted RR 1.33; 95%CI 1.15, 1.54), but not in the current period (adjusted RR 0.98; 95%CI 0.87, 1.11).

Conclusions

A clear clinical trial effect on suppression of HIV replication was observed in the early HAART period but not in the current period.     

Identification of salt stress-induced transcripts in potato leaves by cDNA-AFLP

Potato (Solanum tuberosum L.) is highly sensitive to salt stress, which is one of the most important factors limiting plant cultivation. The investigation of plant response to high salinity was envisaged in this report using cDNA-amplified fragment length polymorphism (AFLP). This technique was applied to salt- stressed and control potato plants (cv. Nicola). The expression profiles showed approx 5000 bands. Of these, 154 were upregulated and 120 were repressed by salt stress. In this study we have only considered cDNA fragments that seem to be originated from salt-induced mRNA. Eighteen fragments were then reamplified, cloned, and sequenced. Sequence comparison of these cDNA, identified in response to salt stress in potato, revealed that some of them present homologies with proteins in other species that are involved in cell wall structure and turnover such as proline-rich proteins and beta-galactosidase. A number of identified clones encoded putative stress response proteins such as NADP-dependant glyceraldehyde dehydrogenase and wound-induced protein. In addition, some of them encode proteins related to hypersensitive response against pathogens such as putative late blight and nematode as well as putative pathogenesis-related proteins. These cDNA seem to be differentially expressed in the presence of salt stress as shown by Northern blot or reverse Northern hybridization experiments.     

Structural analysis of Siah1-Siah-interacting protein interactions and insights into the assembly of an E3 ligase multiprotein complex

Siah1 is the central component of a multiprotein E3 ubiquitin ligase complex that targets beta-catenin for destruction in response to p53 activation. The E3 complex comprises, in addition to Siah1, Siah-interacting protein (SIP), the adaptor protein Skp1, and the F-box protein Ebi. Here we show that SIP engages Siah1 by means of two elements, both of which are required for mediating beta-catenin destruction in cells. An N-terminal dimerization domain of SIP sits across the saddle-shaped upper surface of Siah1, with two extended legs packing against the sides of Siah1 by means of a consensus PXAXVXP motif that is common to a family of Siah-binding proteins. The C-terminal domain of SIP, which binds to Skp1, protrudes from the lower surface of Siah1, and we propose that this surface provides the scaffold for bringing substrate and the E2 enzyme into apposition in the functional complex.     

CIN85 regulates the ligand-dependent endocytosis of the IgE receptor: a new molecular mechanism to dampen mast cell function

Ligation of the high-affinity receptor for IgE (Fc epsilonRI), constitutively expressed on mast cells and basophils, promotes cell activation and immediate release of allergic mediators. Furthermore, Fc epsilonRI up-regulation on APC from atopic donors is involved in the pathophysiology of allergic diseases. In consideration of the clinical relevance of the IgE receptor, the down-modulation of Fc epsilonRI expression in mast cells may represent a potential target for handling atopic diseases. In an effort to identify new molecular mechanisms involved in attenuating Fc epsilonRI expression and signaling, we focused our attention on CIN85, a scaffold molecule that regulates, in concert with the ubiquitin ligase Cbl, the clathrin-mediated endocytosis of several receptor tyrosine kinases. In the present study, we show that endogenous CIN85 is recruited in Cbl-containing complexes after engagement of the Fc epsilonRI on a mast cell line and drives ligand-induced receptor internalization. By confocal microscopic analysis, we provide evidence that CIN85 directs a more rapid receptor sorting in early endosomes and delivery to a lysosomal compartment. Furthermore, biochemical studies indicate that CIN85 plays a role in reducing the expression of receptor complex. Finally, we demonstrate that CIN85-overexpressing mast cells are dramatically impaired in their ability to degranulate following Ag stimulation, suggesting that the accelerated internalization of activated receptors by perturbing the propagation of Fc epsilonRI signaling may contribute to dampen the functional response. This role of CIN85 could be extended to include other multimeric immune receptors, such as the T and B cell receptors, providing a more general molecular mechanism for attenuating immune responses.