Domain analysis of lipoprotein LppQ in Mycoplasma mycoides subsp. mycoides SC

The lipoprotein LppQ is the most prominent antigen of Mycoplasma mycoides subsp. mycoides small colony type (SC) during infection of cattle. This pathogen causes contagious bovine pleuropneumonia (CBPP), a devastating disease of considerable socio-economic importance in many countries worldwide. The dominant antigenicity and high specificity for M. mycoides subsp. mycoides SC of lipoprotein LppQ have been exploited for serological diagnosis and for epidemiological investigations of CBPP. Scanning electron microscopy and immunogold labelling were used to provide ultrastructural evidence that LppQ is located to the cell membrane at the outer surface of M. mycoides subsp. mycoides SC. The selectivity and specificity of this method were demonstrated through discriminating localization of extracellular (i.e., in the zone of contact with host cells) vs. integral membrane domains of LppQ. Thus, our findings support the suggestion that the accessible N-terminal domain of LppQ is surface exposed and such surface localization may be implicated in the pathogenesis of CBPP

Thermal history of the central Gotthard and Aar massifs, European Alps: Evidence for steady state, long-term exhumation

International audienceQuantifying long-term exhumation rates is a prerequisite for understanding the geodynamic evolution of orogens and their exogenic and endogenic driving forces. Here we reconstruct the exhumation history of the central Aar and Gotthard external crystalline massifs in the European Alps using apatite and zircon fission track and apatite (U-Th)/He data. Age-elevation relationships and time-temperature paths derived from thermal history modeling are interpreted to reflect nearly constant exhumation of ∼0.5 km/Ma since ∼14 Ma. A slightly accelerated rate (∼0.7 km/Ma) occurred from 16 to 14 Ma and again from 10 to 7 Ma. Faster exhumation between 16 and 14 Ma is most likely linked to indentation of the Adriatic wedge and related thrusting along the Alpine sole thrust, which, in turn, caused uplift and exhumation in the external crystalline massifs. The data suggest nearly steady, moderate exhumation rates since ∼14 Ma, regardless of major exogenic and endogenic forces such as a change to wetter climate conditions around 5 Ma or orogen-perpendicular extension initiated in Pliocene times. Recent uplift and denudation rates, interpreted to be the result of climate fluctuations and associated increase in erosional efficiency, are nearly twice this ∼0.5 km/Ma paleoexhumation rate

Chemiluminescence and Structure Characteristics of a H2/O2 Downward Inverse Diffusion Flame

International audienceAn experimental study was performed to investigate the effects of the burner geometry on the heat released and on the structure of multi-fuel-jet inverse diffusion flames (MIDF). Two different burner configurations were compared at different equivalence ratios and jet velocities using direct visualization and OH* chemiluminescence. Two downward burner were used, with H2 and O2 as fuel and oxidizer, respectively. A post-processing of the OH* chemiluminescence data was carried out with the Abel deconvolution through Matlab®. OH* emission intensities show a dependency on the burner geometry, as well as flame structure characteristics

Burner lip temperature and stabilization of a non-premixed jet flame

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Induction of cytochrome P450 enzymes in primary equine hepatocyte culture

In this study, we established cell culture conditions for primary equine hepatocytes allowing cytochrome P450 enzyme (CYP) induction experiments. Hepatocytes were isolated after a modified method of Bakala et al. (2003) and cultivated on collagen I coated plates. Three different media were compared for their influence on morphology, viability and CYP activity of the hepatocytes. CYP activity was evaluated with the fluorescent substrate 7-benzyloxy-4-trifluoromethylcoumarin. Induction experiments were carried out with rifampicin, dexamethasone or phenobarbital. Concentration-response curves for induction with rifampicin were created. Williams' medium E showed the best results on morphology and viability of the hepatocytes and was therefore used for the following induction experiments. Cells cultured in Dulbecco's Modified Eagle Medium were not inducible. Incubation with rifampicin increased the CYP activity in two different hepatocyte preparations in a dose dependent manner (EC50=1.20 μM and 6.06 μM; Emax=4.1- and 3.4-fold induction). No increase in CYP activity was detected after incubation with dexamethasone or phenobarbital. The hepatocyte culture conditions established in this study proved to be valuable for investigation of the induction of equine CYPs. In further studies, other equine drugs can be evaluated for CYP induction with this in vitro system

Comparison of phenotypes of childhood wheeze and cough in 2 independent cohorts

BACKGROUND Among children with wheeze and recurrent cough there is great variation in clinical presentation and time course of the disease. We previously distinguished 5 phenotypes of wheeze and cough in early childhood by applying latent class analysis to longitudinal data from a population-based cohort (original cohort). OBJECTIVE To validate previously identified phenotypes of childhood cough and wheeze in an independent cohort. METHODS We included 903 children reporting wheeze or recurrent cough from an independent population-based cohort (validation cohort). As in the original cohort, we used latent class analysis to identify phenotypes on the basis of symptoms of wheeze and cough at 2 time points (preschool and school age) and objective measurements of atopy, lung function, and airway responsiveness (school age). Prognostic outcomes (wheeze, bronchodilator use, cough apart from colds) 5 years later were compared across phenotypes. RESULTS When using a 5-phenotype model, the analysis distinguished 3 phenotypes of wheeze and 2 of cough as in the original cohort. Two phenotypes were closely similar in both cohorts: Atopic persistent wheeze (persistent multiple trigger wheeze and chronic cough, atopy and reduced lung function, poor prognosis) and transient viral wheeze (early-onset transient wheeze with viral triggers, favorable prognosis). The other phenotypes differed more between cohorts. These differences might be explained by differences in age at measurements. CONCLUSIONS Applying the same method to 2 different cohorts, we consistently identified 2 phenotypes of wheeze (atopic persistent wheeze, transient viral wheeze), suggesting that these represent distinct disease processes. Differences found in other phenotypes suggest that the age when features are assessed is critical and should be considered carefully when defining phenotypes

Abnormal keratinocyte differentiation in the nasal planum of Labrador Retrievers with hereditary nasal parakeratosis (HNPK).

Hereditary nasal parakeratosis (HNPK) is an inherited disorder described in Labrador Retrievers and Greyhounds. It has been associated with breed-specific variants in the SUV39H2 gene encoding a histone 3 methyltransferase involved in epigenetic silencing. Formalin-fixed biopsies of the nasal planum of Labrador Retrievers were screened by immunofluorescence microscopy for the presence and distribution of epidermal proliferation and differentiation markers. Gene expression of these markers was further analysed using RNA sequencing (RNA-seq) and ultrastructural epidermal differences were investigated by electron microscopy. Differentiation of the nasal planum in the basal and suprabasal epidermal layers of HNPK-affected dogs (n = 6) was similar compared to control dogs (n = 6). In the upper epidermal layers, clear modifications were noticed. Loricrin protein was absent in HNPK-affected nasal planum sections in contrast to sections of the same location of control dogs. However, loricrin was present in the epidermis of paw pads and abdominal skin from HNPK dogs and healthy control dogs. The patterns of keratins K1, K10 and K14, were not markedly altered in the nasal planum of HNPK-affected dogs while the expression of the terminal differentiation marker involucrin appeared less regular. Based on RNA-seq, LOR and IVL expression levels were significantly decreased, while KRT1, KRT10 and KRT14 levels were up-regulated (log2fold-changes of 2.67, 3.19 and 1.71, respectively) in HNPK-affected nasal planum (n = 3) compared to control dogs (n = 3). Electron microscopical analysis revealed structural alterations in keratinocytes and stratum corneum, and disrupted keratinocyte adhesions and distended intercellular spaces in lesional samples (n = 3) compared to a sample of a healthy control dog (n = 1). Our findings demonstrate aberrant keratinocyte terminal differentiation of the nasal planum of HNPK-affected Labrador Retrievers and provide insights into biological consequences of this inactive SUV39H2 gene variant

Lifting and Splitting of Nonpremixed Methane/Air Flames Due to Reactant Preheating

<div><p>In order to assess the impact of initial reactant temperature on the occurrence of local extinction (LE) and the subsequent lifting process of non-premixed attached flames with increasing fuel injection velocity, hydroxyl radical planar laser-induced fluorescence (OH-PLIF) and high-speed CH*-chemiluminescence visualizations were conducted in a methane/air jet-flame, with preheating up to 1000 K. LE occurrence probability increases when approaching lifting, and the preheating level (T_ox,ref) affects the probability density function (PDF) shape of LE axial origin. At low T_ox,ref, partial lifting events occur near the burner lip, eventually leading the flame to lift directly from the very flame base. At higher T_ox,ref, partial lifting events no longer occur, and LE is mostly witnessed in the flame breakpoint zone (axially from 1 to 3 jet diameters), resulting in a breakpoint lifting process. For very high T_ox,ref (1000 K), local extinctions become widespread in the breakpoint zone so that a stable split flame is achieved prior to the lifted regime.</p></div

Study of a V-shape flame based on IR spectroscopy and IR imaging

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