A nonradioisotope biomedical assay for intact oligonucleotide and its chain-shortened metabolites used for determination of exposure and elimination half-life of antisense drugs in tissue.

Rigorous extraction methods coupled with capillary gel electrophoresis (CGE) provide a basis for a nonradiolabel assay for quantitation of intact antisense drug and its numerous chain-shortened metabolites. As part of the validation of the CGE method, we compared the quantitation of unlabeled ISIS 3521 (ISI 641A) and its chain-shortened metabolites with total radioactivity of [(35)S]-ISIS 3521. ISIS 3521 was labeled on the fifth nucleotide linkage from the 5'-end with (35)S by well-established methods. Multiple tissues collected from rats after administration of [(35)S]-ISIS 3521 were assayed by both radiolabel (liquid scintillation spectroscopy) and CGE methods. The CGE method provided accurate quantitation of the drug and its metabolites in kidney cortex and liver tissues. The correlation between methods for multiple tissues over time was excellent with 88.5% of the measurements being statistically equivalent. These data suggest that CGE is an accurate means of quantitating oligonucleotide in tissue and that it compares favorably with traditional radiochemical techniques. Clearance half-lives for total measurable oligonucleotides were equivalent to clearance of total radioactivity in both liver and kidney with the longest clearance half-life associated with the kidney.     

The generic placement of a morphologically enigmatic species in Asteraceae: evidence from ITS sequences

 Bidens cordylocarpa is a high polyploid species restricted in distribution to stream sides in the mountains of Jalisco, Mexico. The morphologically enigmatic species was originally described as a member of the genus Coreopsis, but later transferred to Bidens, largely because the involucral bracts appear most similar to Bidens. Characters of the cypselae, often useful in generic placement, are of no value for this species because the fruits have features not detected in either Bidens or Coreopsis. Sequences from the internal transcribed spacer region of nuclear ribosomal DNA (ITS) were used to assess the relationships of Bidens cordylocarpa. The molecular phylogeny places B. cordylocarpa in a strongly supported clade of Mexican and South American Bidens, and provides more definitive evidence of relationships than morphology, chromosome number, or secondary chemistry. Molecular, morphological, and chromosomal data suggest that B. cordylocarpa is an ancient polyploid, perhaps the remnant of a polyploid complex. Received August 28, 2000 Accepted February 11, 2001     

The Biopolymer Markup Language.

SUMMARY: An XML derived from a data model designed to be a hierarchical representation of an organism has been specified and a browser to use this language has been developed. AVAILABILITY: The language definition is available in HTML form at http://www.proteometrics.com/BIOML/. The BioML browser is available on request from the author.     

Rapid, simple and sensitive high-performance liquid chromatographic method for detection and determination of acyclovir in human plasma and its use in bioavailability studies

A rapid, simple and sensitive reversed-phase high-performance liquid chromatographic (HPLC) method has been developed for the measurement of acyclovir concentrations in human plasma and its use in bioavailability studies is evaluated. Unchanged acyclovir has been quantified without the introduction of an internal standard using the present method. Human plasma proteins were selectively precipitated by the addition of 7% perchloric acid to spiked plasma samples or to the plasma samples obtained after acyclovir administration to human volunteers and the mixture was spun at 1000 g for 10 min. The supernatant was directly injected into a Novaflex C₁₈ column and detected at 254 nm. The mobile phase consisted of octane sulfonic acid buffer (pH 2.5) and methanol (92:08). The limit of quantitation for acyclovir in plasma was 20 ng/ml, which enabled the determination of the area under the curve (AUC) more precisely, that is, it is much closer to its extrapolated value. The present method has been successfully applied to samples from bioavailability studies.     

Cloning of aroG, the gene coding for phospho-2-keto-3-deoxy-heptonate aldolase(phe), in Escherichia coli K-12, and subcloning of the aroG promoter and operator in a promoter-detecting plasmid

Defective transducing phages carrying aroG, the structural gene for phenylalanine (phe)-inhibitable phospho-2-keto-heptonate aldolase (EC 4.1.2.15; previously known as 3-deoxy-D-arabinoheptulosonate-7-phosphate synthetase[phe]), have been isolated, and DNA from two of these phages has been used to construct a restriction map of the region from att lambda to aroG. A 7.6-kb PstI-HindIII fragment from one of these phages was cloned into pBR322 and shown to contain aroG. The location of aroG within the 7.6 kb was established by subcloning and Tn3 transpositional mutagenesis. A fragment carrying the aroG promoter and operator has been cloned into a high copy number promoter-cloning vector (pMC489), and the resulting aroGpo-LacZ' (alpha) fusion subcloned in a low copy number vector. Strains with this fusion on the low copy number vector exhibit negative regulation of beta-galactosidase expression by both phenylalanine and tryptophan and positive regulation by tyrosine in a tyrR+ background.     

A rapid single-stranded cloning strategy for producing a sequential series of overlapping clones for use in DNA sequencing: application to sequencing the corn mitochondrial 18 S rDNA

A simple new procedure was described for producing a sequential series of overlapping clones for use in DNA sequencing. The technique used single-stranded M13 DNA and complementary DNA oligomers to form specific cleavage and ligation substrates. It was, therefore, independent of the sequence of the DNA cloned into the vector. Deletions of varying sizes were generated from one end of the insert through the 3' to 5' exonuclease activity of T4 DNA polymerase. The approximate size of the deletion and therefore the starting point for DNA sequencing could be estimated by electrophoresis of the subcloned phage DNA on a agarose gel. This greatly reduced the number of templates that must be sequenced to obtain a complete sequence. The entire procedure could be carried out in one tube in less than a day. The procedure was used to subclone and sequence the maize mitochondrial 18 S rDNA and 5' flanking region (2622 bases) in less than a week. Other applications of oligomers and single-stranded DNA in the construction of insertions, deletions, and cDNAs are discussed.     

High Altitude Frogs (Rana kukonoris) Adopt a Diversified Bethedging Strategy in the Face of Environmental Unpredictability

Environmental unpredictability can influence strategies of maternal investment among eggs within a clutch. Models predict that breeding females should adopt a diversified bet-hedging strategy in unpredictable environments, but empirical field evidence from Asia is scarce. Here we tested this hypothesis by exploring spatial patterns in egg size along an altitudinal gradient in a frog species(Rana kukunoris) inhabiting the Tibetan Plateau. Within-clutch variability in egg size increased as the environment became variable(e.g., lower mean monthly temperature and mean monthly rainfall at higher altitudes), and populations in environments with more unpredictable rainfall produced eggs that were smaller and more variable in size. We provide support for a diversified bet-hedging strategy in high-altitude environments, which experience dynamic weather patterns and therefore are of unpredictable environmental quality. This strategy may be an adaptive response to lower environmental quality and higher unpredictable environmental variance. Such a strategy should increase the likelihood of breeding success and maximize maternal lifetime fitness by producing offspring that are adapted to current environmental conditions. We speculate that in high-altitude environments prone to physical disturbance, breeding females are unable to consistently produce the optimal egg size due to physiological constraints imposed by environmental conditions(e.g., duration of the active season, food availability). Species and populations whose breeding strategies are adapted to cope with uncertain environmental conditions by adjusting offspring size and therefore quality show a remarkable degree of ability to cope with future climatic changes.     

Purification and characterization of carbon monoxide dehydrogenase, a nickel, zinc, iron-sulfur protein, from Rhodospirillum rubrum

Carbon monoxide dehydrogenase (CO dehydrogenase) from Rhodospirillum rubrum was shown to be an oxygen-sensitive, nickel, iron-sulfur, and zinc-containing protein that was induced by carbon monoxide (CO). The enzyme was purified 212-fold by heat treatment, ion-exchange, and hydroxylapatite chromatography and preparative gel electrophoresis. The purified protein, active as a monomer of Mr = 61,800, existed in two forms that were comprised of identical polypeptides and differed in metal content. Form 1 comprised 90% of the final activity, had a specific activity of 1,079 mumol CO oxidized per min-1 mg-1, and contained 7 iron, 6 sulfur, 0.6 nickel, and 0.4 zinc/monomer. Form 2 had a lower specific activity (694 mumol CO min-1 mg-1) and contained 9 iron, 8 sulfur, 1.4 nickel, and 0.8 zinc/monomer. Reduction of either form by CO or dithionite resulted in identical, rhombic ESR spectra with g-values of 2.042, 1.939, and 1.888. Form 2 exhibited a 2-fold higher integrated spin concentration, supporting the conclusion that it contained an additional reducible metal center(s). Cells grown in the presence of 63NiCl2 incorporated 63Ni into CO dehydrogenase. Although nickel was clearly present in the protein, it was not ESR-active under any conditions tested. R. rubrum CO dehydrogenase was antigenically distinct from the CO dehydrogenases from Methanosarcina barkeri and Clostridium thermoaceticum.