Virus Detection and Monitoring of Viral Load in Crimean-Congo Hemorrhagic Fever Virus Patients

We developed a real-time reverse transcription–-PCR that detected 1,164 copies/mL of Crimean-Congo hemorrhagic fever virus per milliliter of serum at 95% probability (probit analysis) and was 100% concordant with nested PCR on 63 samples from 31 patients with confirmed infection. Infected patients who died appeared to have higher viral loads; low viral loads correlated with IgG detection

A Novel Diagnostic Target in the Hepatitis C Virus Genome

Christian Drosten and colleagues develop, validate, and make openly available a prototype hepatitis C virus assay based on the conserved 3' X-tail element, with potential for clinical use in developing countries

Technical Note: Harmonized retrieval of column-integrated atmospheric water vapor from the FTIR network - First examples for long-term records and station trends

We present a method for harmonized retrieval of integrated water vapor (IWV) from existing, long-term, measurement records at the ground-based mid-infrared solar FTIR spectrometry stations of the Network for the Detection of Atmospheric Composition Change (NDACC). Correlation of IWV from FTIR with radiosondes shows an ideal slope of 1.00(3). This optimum matching is achieved via tuning one FTIR retrieval parameter, i.e., the strength of a Tikhonov regularization constraining the derivative (with respect to height) of retrieved water profiles given in per cent difference relative to an a priori profile. All other FTIR-sonde correlation parameters (intercept = 0.02(12) mm, bias = 0.02(5) mm, standard deviation of coincident IWV differences (stdv) = 0.27 mm, R = 0.99) are comparable to or better than results for all other ground-based IWV sounding techniques given in the literature. An FTIR-FTIR side-by-side intercomparison reveals a strong exponential increase in stdv as a function of increasing temporal mismatch starting at Δt ≈ 1 minute. This is due to atmospheric water vapor variability. Based on this result we derive an upper limit for the precision of the FTIR IWV retrieval for the smallest Δt (= 3.75 min) still giving a statistically sufficient sample (32 coincidences), i.e., precision (IWVFTIR) < 0.05 mm (or 2.2 % of the mean IWV). The bias of the IWV retrievals from the two different FTIR instruments is nearly negligible (0.02(1) mm). The optimized FTIR IWV retrieval is set up in the standard NDACC algorithm SFIT 2 without changes to the code. A concept for harmonized transfer of the retrieval between different stations deals with all relevant control parameters; it includes correction for differing spectral point spacings (via regularization strength), and final quality selection of the retrievals (excluding the highest residuals (measurement minus model), 5% of the total). As first application examples long-term IWV data sets are retrieved from the FTIR records of the Zugspitze (47.4 °N, 11.0 °E, 2964 m a.s.l.) and Jungfraujoch (46.5 °N, 8.0 °E, 3580 m a.s.l.) NDACC sites. Station-trend analysis comprises a linear fit after subtracting an intra-annual model (3 Fourier components) and constructing an uncertainty interval [95 % confidence] via bootstrap resampling. For the Zugspitze a significant trend of 0.79 [0.65, 0.92] mm/decade is found for the time interval [1996 - 2008], whereas for the Jungfraujoch no significant trend is found. This confirms recent findings that strong variations of IWV trends do occur above land on the local to regional scale (≈250 km) in spite of homogeneous surface temperature trends. This paper provides a basis for future exploitation of more than a dozen existing, multi-decadal FTIR measurement records around the globe for climate studies

Microsporidia amitochondrial protists possess a 70-kDa heat shock protein gene of mitochondrial evolutionary origin

An intronless gene encoding a protein of 592 amino acid residues with similarity to 70-kDa heat shock proteins (HSP70s) has been cloned and sequenced from the amitochondrial protist Encephalitozoon cuniculi (phylum Microsporidia). Southern blot analyses show the presence of a single gene copy located on chromosome XI. The encoded protein exhibits an N-terminal hydrophobic leader sequence and two motifs shared by proteobacterial and mitochondrially expressed HSP70 homologs. Phylogenetic analysis using maximum likelihood and evolutionary distances place the E. cuniculi sequence in the cluster of mitochondrially expressed HSP70s, with a higher evolutionary rate than those of homologous sequences. Similar results were obtained after cloning a fragment of the homologous gene in the closely related species E. hellem. The presence of a nuclear targeting signal-like sequence supports a role of the Encephalitozoon HSP70 as a molecular chaperone of nuclear proteins. No evidence for cytosolic or endoplasmic reticulum forms of HSP70 was obtained through PCR amplification. These data suggest that Encephalitozoon species have evolved from an ancestor bearing mitochondria, which is in disagreement with the postulated presymbiotic origin of Microsporidia. The specific role and intracellular localization of the mitochondrial HSP70-like protein remain to be elucidated

Phylogenetic analysis of the small subunit ribosomal RNA of <i>Marteilia refringens</i> validates the existence of phylum Paramyxea (Desportes and Perkins 1990)

Marteilia refringens is recognized as one of the most significant pathogens of bivalve molluscs. The nucleotide sequence of the small subunit ribosomal RNA gene of Marteilia refringens is used to elucidate the phylogenetic position of the phylum Paramyxea. Genomic DNA was extracted from sporangia of Marteilia, purified from infected blue mussels, Mytilus edulis, and flat oysters, Ostrea edulis. The sequences obtained from Marteilia species purified from both oysters and mussels were identical. The sequence identity was confirmed by in situ hybridization using a DNA probe targeted to a variable region of the ribosomal DNA. The small subunit ribosomal RNA gene sequence of M. refringens is very different from all known sequences of eukaryotic organisms, including those of myxosporeans and haplosporeans. Therefore, the phylum Paramyxea should continue to be recognized as an independent eukaryotic phylum

EnP1 and EnP2, two proteins associated with the Encephalitozoon cuniculi endospore, the chitin-rich inner layer of the microsporidian spore wall.

International audienceMicrosporidia are obligate intracellular parasites forming environmentally resistant spores that harbour a rigid cell wall. This wall comprises an outer layer or exospore and a chitin-rich inner layer or endospore. So far, only a chitin deacetylase-like protein has been shown to localize to the Encephalitozoon cuniculi endospore and either one or two proteins have been clearly assigned to the exospore in two Encephalitozoon species: SWP1 in E. cuniculi, SWP1 and SWP2 in Encephalitozoon intestinalis. Here, we report the identification of two new spore wall proteins in E. cuniculi, EnP1 and EnP2, the genes of which are both located on chromosome I (ECU01_0820 and ECU01_1270, respectively) and have no known homologue. Detected by immunoscreening of an E. cuniculi cDNA library, enp1 is characterized by small-sized 5' and 3' untranslated regions and is highly expressed throughout the whole intracellular cycle. The encoded basic 40 kDa antigen displays a high proportion of cysteine residues, arguing for a significant role of disulfide bridges in spore wall assembly. EnP2 is a 22 kDa serine-rich protein that is predicted to be O-glycosylated and glycosylated phosphatidyl inositol-anchored. Although having been identified by mass spectrometry of a dithiothreitol-soluble fraction, this protein contains only two cysteine residues. Mouse polyclonal antibodies were raised against EnP1 and EnP2 recombinant proteins produced in Escherichia coli Our immunolocalisation data indicate that EnP1 and EnP2 are targeted to the cell surface as early as the onset of sporogony and are finally associated with the chitin-rich layer of the wall in mature spores

Méthodes d'études des micro-organismes dans l'environnement. Chapitre 17

Partie 5: Les outils de l'écologie microbienneNational audienc