ABSTRACT
A simple, non-moving dual-stage CO2 jet modulator is described, which cools two short sections of the front end of the second-dimension column of a comprehensive two-dimensional gas chromatograph. A stream of expanding CO2 is sprayed directly onto this capillary column to trap small fractions eluting from the first-dimension column. Remobilization of the trapped analytes is performed by direct heating by the GC oven air. Installation, maintenance and control of the modulator is simple. Focusing and remobilization of the fractions is a very efficient process, as the bandwidths of the re-injected pulses are less than 10 ms. As a result, alkane peaks eluting from the second-dimension column have peakwidths at the baseline of only 120 ms.
Subject(s)
Chromatography, Gas/methods , Carbon DioxideABSTRACT
The biosynthetic gene cluster (12.3 kb) of mersacidin, a lanthionine-containing antimicrobial peptide, is located on the chromosome of the producer, Bacillus sp. strain HIL Y-85,54728 in a region that corresponds to 348 degrees on the chromosome of Bacillus subtilis 168. It consists of 10 open reading frames and contains, in addition to the previously described mersacidin structural gene mrsA (G. Bierbaum, H. Brötz, K.-P. Koller, and H.-G. Sahl, FEMS Microbiol. Lett. 127:121-126, 1995), two genes, mrsM and mrsD, coding for enzymes involved in posttranslational modification of the prepeptide; one gene, mrsT, coding for a transporter with an associated protease domain; and three genes, mrsF, mrsG, and mrsE, encoding a group B ABC transporter that could be involved in producer self-protection. Additionally, three regulatory genes are part of the gene cluster, i.e., mrsR2 and mrsK2, which encode a two-component regulatory system which seems to be necessary for the transcription of the mrsFGE operon, and mrsR1, which encodes a protein with similarity to response regulators. Transcription of mrsA sets in at early stationary phase (between 8 and 16 h of culture).
Subject(s)
Anti-Bacterial Agents/biosynthesis , Bacillus/enzymology , Bacillus/genetics , Genes, Bacterial , Peptides , ATP-Binding Cassette Transporters/genetics , Amino Acid Sequence , Anti-Bacterial Agents/pharmacology , Bacillus/drug effects , Bacillus/growth & development , Bacteriocins , Gene Expression Regulation, Bacterial , Genes, Regulator , Molecular Sequence Data , Multigene Family , Sequence Analysis, DNA , Transcription, GeneticABSTRACT
Oral endotracheal intubation of guineapigs as reported in the literature, is considered to be extremely difficult. Because of this, we constructed special equipment and developed a technique to facilitate the procedure. A special restraint device was designed to position the guineapig. Utilizing a laryngoscope and an operating microscope for visualization then makes intubation easy to perform.
