MicroRNA 10a marks regulatory T cells

MicroRNAs (miRNAs) are crucial for regulatory T cell (Treg) stability and function. We report that microRNA-10a (miR-10a) is expressed in Tregs but not in other T cells including individual thymocyte subsets. Expression profiling in inbred mouse strains demonstrated that non-obese diabetic (NOD) mice with a genetic susceptibility for autoimmune diabetes have lower Treg-specific miR-10a expression than C57BL/6J autoimmune resistant mice. Inhibition of miR-10a expression in vitro leads to reduced FoxP3 expression levels and miR-10a expression is lower in unstable "exFoxP3" T cells. Unstable in vitro TGF-?-induced, iTregs do not express miR-10a unless cultured in the presence of retinoic acid (RA) which has been associated with increased stability of iTreg, suggesting that miR-10a might play a role in stabilizing Treg. However, genetic ablation of miR-10a neither affected the number and phenotype of natural Treg nor the capacity of conventional T cells to induce FoxP3 in response to TGFβ, RA, or a combination of the two. Thus, miR-10a is selectively expressed in Treg but inhibition by antagomiRs or genetic ablation resulted in discordant effects on FoxP3.     

Gamma Interferon (IFN-γ) Receptor Restricts Systemic Dengue Virus Replication and Prevents Paralysis in IFN-α/β Receptor-Deficient Mice

We previously reported that mice lacking alpha/beta and gamma interferon receptors (IFN-α/βR and -γR) uniformly exhibit paralysis following infection with the dengue virus (DENV) clinical isolate PL046, while only a subset of mice lacking the IFN-γR alone and virtually no mice lacking the IFN-α/βR alone develop paralysis. Here, using a mouse-passaged variant of PL046, strain S221, we show that in the absence of the IFN-α/βR, signaling through the IFN-γR confers approximately 140-fold greater resistance against systemic vascular leakage-associated dengue disease and virtually complete protection from dengue-induced paralysis. Viral replication in the spleen was assessed by immunohistochemistry and flow cytometry, which revealed a reduction in the number of infected cells due to IFN-γR signaling by 2 days after infection, coincident with elevated levels of IFN-γ in the spleen and serum. By 4 days after infection, IFN-γR signaling was found to restrict DENV replication systemically. Clearance of DENV, on the other hand, occurred in the absence of IFN-γR, except in the central nervous system (CNS) (brain and spinal cord), where clearance relied on IFN-γ from CD8⁺ T cells. These results demonstrate the roles of IFN-γR signaling in protection from initial systemic and subsequent CNS disease following DENV infection and demonstrate the importance of CD8⁺ T cells in preventing DENV-induced CNS disease.     

Stereoselective synthesis of pentacyclic steroids functionalized at C-11

We set out to describe an efficient and versatile method for preparing pentacyclic steroids diversely substituted at C-11 from cholic acid, via a stereoselective epoxidation and the epoxide opening as the key steps. The characteristic (1)H and (13)C NMR spectroscopic features of the synthesized compounds are reported.     

Functional characterization of FTDP-17 tau gene mutations through their effects on Xenopus oocyte maturation.

tau gene mutations cause frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17). Here we have used Xenopus oocyte maturation as an indicator of microtubule function. We show that wild-type four-repeat Tau protein inhibits maturation in a concentration-dependent manner, whereas three-repeat Tau has no effect. Of the seven four-repeat Tau proteins with FTDP-17 mutations tested, five (G272V, DeltaK280, P301L, P301S, and V337M) failed to interfere significantly with oocyte maturation, demonstrating a greatly reduced ability to interact with microtubules. One mutant protein (R406W) almost behaved like wild-type Tau, and one (S305N) inhibited maturation more strongly than wild-type Tau. With the exception of R406W, wild-type Tau and all the mutants studied were similarly phosphorylated during the Xenopus oocyte maturation, and this was independent of their effects on this process. Data obtained with R406W and S305N may be related to charge changes (phosphorylation and basic amino acids). Our results demonstrate variable effects of FTDP-17 mutations on microtubules in an intact cell situation. Those findings establish Xenopus oocyte maturation as a system allowing the study of the functional effects of tau gene mutations in a quantitative manner.     

AC-electrophoretic deposition of glucose oxidase

The electrophoretic deposition of glucose oxidase from water using asymmetrical alternating voltages is investigated. Using asymmetric voltages, glucose oxidase layers with a thickness of 7 μm could be deposited on a platinum electrode in 20 min time as verified with a microbalance, carbon analysis and scanning electron microscopy. In contrast, if a symmetrical alternating signal is used under the same conditions, a layer of 0.5 μm is formed. We believe the deposition is due to two effects: the electrophoretic migration of the enzyme towards the deposition electrode and the pH induced precipitation of the enzyme near the deposition electrode. The electrophoretic migration is due to the non-linear dependence of the electrophoretic mobility on the electric field caused by the asymmetry of the applied alternating current signal. In addition, pH changes near the deposition electrode drive the enzyme towards its point of zero charge (PZC), perhaps causing the precipitation of GOx on the substrate. The effect of amplitude, frequency, deposition time and GOx concentration on the deposition rate was studied. An amplitude of 160 V_p–p and a frequency of 30 Hz was found to be optimal for the formation of thick enzyme layers, which excludes a big part of the interferences.     

Environmental determinants of the <Emphasis Type="Italic">Mycobacterium bovis</Emphasis> concomitant infection in cattle and badgers in France

Landscape epidemiology analyses how environmental characteristics influence pathogen transmission between hosts of one or several species, by inducing constraints on space use by hosts, and/or on pathogen survival in the environment. Here, we analysed how environmental variables could be associated with the Mycobacterium bovis concomitant infection in both cattle and badgers, in an area of south-western France. We defined circular spatial units (500 and 1000 m radiuses) centred on 113 setts of trapped badgers and including cattle pastures. The characteristics of spatial units where only one species had been found infected were compared with the ones where both cattle and badgers had been found infected. A multivariate logistic model was used to analyse the association between concomitant infection in both species and three groups of variables describing landscape, animal population and terrain features of spatial units. The terrain ruggedness index of pastures and the percentage of sand in their soil were positively associated with the odds of concomitant infection in cattle and badgers in the spatial units. The number of neighbouring badger groups was negatively associated with the odds of concomitant infection (spatial units of 1000 m radius), whereas the number of crop parcels was positively associated with the odds of concomitant infection (spatial units of 500 m radius). These results suggest that terrain features, badger population structure and food availability may influence the spread of M. bovis infection between badgers and cattle, leading to concomitant infection of both species.     

Chemical Composition and Antimicrobial Activity of Essential Oils from the Aerial Parts of Asteriscus graveolens (Forssk.) Less. and Pulicaria incisa (Lam.) DC.: Two Asteraceae Herbs Growing Wild in the Hoggar

In recent years, antimicrobial activities of essential oils have been intensively explored, mainly in researching and developing new antimicrobial agents to overcome microbial resistance. The present study investigates the chemical composition and antimicrobial activities of essential oils obtained from two Asteraceae: Asteriscus graveolens (Forssk .) Less . and Pulicaria incisa (Lam .) DC. Chemical analysis was performed using a combination of capillary GC‐FID and GC/MS analytical techniques. The major component of Asteriscus graveolens were cis‐chrysanthenyl acetate (31.1%), myrtenyl acetate (15.1%), and kessane (11.5%), while for Pulicaria incisa the main components were chrysanthenone (45.3%) and 2,6‐dimethylphenol (12.6%). The oils obtained from the aerial parts were tested against sixteen microbial strains by agar well diffusion technique and dilution methods and showed minimum inhibitory concentrations (MIC) in the range of 19 – 1250 μg/ml. A good antibacterial activity against a common nosocomial pathogen, Acinetobacter baumanniiATCC 19606 was observed, especially from Pulicaria incisa essential oil, with a MIC value up to 19 μg/ml. These results give significant information about the pharmacological activity of these essential oils, which suggest their benefits to human health, having the potential to be used for medical purposes.