[Pneumomediastinum complicating the anti-synthetase syndrome].

Introduction: Pneumomediastinum is a rare but classical complication of dermatomyositis. Its development is a serious matter and necessitates prompt recourse to aggressive treatment with corticosteroids combined with immuno-suppressants or intravenous human immunoglobulin.

Case Report: We report the case of a 63 year old woman presenting with pulmonary infiltration, in the presence of dermatomyositis, as a clinical manifestation of the anti-synthetase syndrome.

An improved anion-exchange HPLC method for the detection and purification of adenoviral particles.

We have developed an anion-exchange high-performance liquid chromatography (HPLC) method using Q Sepharose XL (Amersham Pharmacia Biotech) as adsorbent to analyze samples containing adenovirus. This method has several major advantages over the HPLC method previously described for quantitating particles, namely (1) a >10-fold improvement in the detection limit of adenovirus in crude preparations; (2) absence of interferences originating from nucleic acids and proteins which usually contaminate crude samples; (3) unprecedented sharpness and symmetry of adenovirus peak, rendering the identification of the viral peak unambiguous, even in extremely crude and dilute preparations; and (4) no enzymatic treatment required even for crude samples. This assay was used to quantitate particles in samples taken at the transfection and amplification stages of production of various recombinant adenovirus, and in cultures of wild-type adenovirus of different serotypes.

Purification of peptide synthetases involved in pristinamycin I biosynthesis.

Several assays of pristinamycin I synthetases based on adenylate or thioester formation were developed. Purification to near homogeneity of these enzymatic activities from cell extracts of Streptomyces pristinaespiralis showed that three enzymes could activate all pristinamycin I precursors. SnbA, a 3-hydroxypicolinic acid: AMP ligase activating the first pristinamycin I residue, was purified 200-fold, using an ATP-pyrophosphate exchange assay.

Identification and analysis of genes from Streptomyces pristinaespiralis encoding enzymes involved in the biosynthesis of the 4-dimethylamino-L-phenylalanine precursor of pristinamycin I.

Four pap genes (papA, papB, papC, papM) were found by sequencing near to snbA, a Streptomyces pristinaespiralis gene which was previously shown to encode one of the pristinamycin I (PI) synthetases. Analysis of the homologies observed from the deduced amino acid sequences suggested that these four genes could be involved in the biosynthesis of the PI precursor 4-dimethylamino-L-phenylalanine (DMPAPA). This was first verified when disruption of papA in S.

Differential behaviors of Staphylococcus aureus and Escherichia coli type II DNA topoisomerases.

Staphylococcus aureus gyrA and gyrB genes encoding DNA gyrase subunits were cloned and coexpressed in Escherichia coli under the control of the T7 promoter-T7 RNA polymerase system, leading to soluble gyrase which was purified to homogeneity. Purified gyrase was catalytically indistinguishable from the gyrase purified from S. aureus and did not contain detectable amounts of topoisomerases from the E.