Comparison of the in vivo clearance of des-AA and des-AABB rat fibrin monomers prepared by different methods

Solubilization of fibrin monomers (Fm's) is usually performed with dilute acetic acid, urea or sodium bromide. These solvents can affect the biological properties of Fm's. Therefore we describe a new method to keep Fm's in solution, under milder conditions i.e. by generating them in Dcate solutions and avoiding non-physiological conditions. The in vivo behaviour of iodinated rat Fm's injected in rats and prepared by this new method was compared with that of Fm's dissolved in acetic acid, urea or sodium bromide.Fm's prepared in Dcate solutions accumulate rapidly, within 10 minutes after injection, in all organs tested, predominantly in kidney, liver and lung, probably by interaction with endothelial cells. The blood radioactivity remains nearly constant during the first 90 minutes and decreases thereafter exponentially. Fm's dissolved in sodium bromide behave similarly. However, Fm's dissolved in acetic acid or urea behave differently and do not accumulate in organs. This suggests that Fm's loose their capability to accumulate in organs and probably to interact with endothelial cells when they have been dissolved in acetic acid or urea.The slow exponential clearance phase does not differ significantly between the various Fm's and their $\text{T}\text{1}\text{2'S}$ are estimated to lie between 5 and 7 hours.     

Assignment of the Charcot-Marie-Tooth neuropathy type 1 (CMT 1a) gene to 17p11.2-p12.

Charcot-Marie-Tooth disease type 1a (CMT 1a) is an autosomal dominant peripheral neuropathy linked to the DNA markers D17S58 and D17S71, located in the pericentromeric region of the chromosome 17p arm. We analyzed an extended 5-generation Belgian family, multiply affected with CMT 1a, for linkage with eight chromosome 17 markers. The results indicated that the CMT 1a mutation is localized in the chromosomal region 17p11.2-p12 between the marker D17S71 and the gene for myosin heavy polypeptide 2 of adult skeletal muscle.     

Four genes in two diverged subfamilies encode the ribulose-1,5-bisphosphate carboxylase small subunit polypeptides of Arabidopsis thaliana

The multigene family encoding the small subunit polypeptides of ribulose-1,5-bisphosphate carboxylase/oxygenase in the crucifer Arabidopsis thaliana has been isolated and the organization and structure of the individual members determined. The family consists of four genes which have been divided into two subfamilies on the basis of linkage and DNA and amino acid sequence similarities. Three of the genes, designated ats1B, ats2B, and ats3B, reside in tandem on an 8 kb stretch of the chromosome. These genes share greater than 95% similarity in DNA sequence and encode polypeptides identical in length and 96.7% similar in amino acid sequence. The fourth gene, ats1A, is at least 10 kb removed from, or completely unlinked to the B subfamily. The B subfamily genes are more similar to each other than to ats1A in nucleotide and amino acid sequence. All four genes are interupted by two introns whose placement within the coding region of the genes is conserved. The introns of the B subfamily genes are similar in length and nucleotide sequence, but show no similarity to the introns of ats1A. Comparison of the DNA sequences within the immediate 5 and 3 flanking sequences among the genes revealed only limited regions of homology. S1 analysis shows that all four genes are expressed.     

Characterization of Oligonucleotide Sequence Isomers in Mixtures Using HPLC/MS

Abstract

A method is described for the analysis of mixtures containing sequence isomers of oligonucleotides. The approach consists of an electrospray ionization mass spectrometric analysis in direct combination with HPLC separation. Mass spectrometry can provide sequence information based on the fragmentation patterns of oligonucleotides allowing the simultaneous characterization of sequence isomers. An example is shown for the characterization of a mixture of dCAGT, dCGTA, dTCAG, dAGTC and dTCGA.     

A PKS/NRPS/FAS Hybrid Gene Cluster from Serratia plymuthica RVH1 Encoding the Biosynthesis of Three Broad Spectrum,Zeamine-Related Antibiotics

Serratia plymuthica strain RVH1, initially isolated from an industrial food processing environment, displays potent antimicrobial activity towards a broad spectrum of Gram-positive and Gram-negative bacterial pathogens. Isolation and subsequent structure determination of bioactive molecules led to the identification of two polyamino antibiotics with the same molecular structure as zeamine and zeamine II as well as a third, closely related analogue, designated zeamine I. The gene cluster encoding the biosynthesis of the zeamine antibiotics was cloned and sequenced and shown to encode FAS, PKS as well as NRPS related enzymes in addition to putative tailoring and export enzymes. Interestingly, several genes show strong homology to the pfa cluster of genes involved in the biosynthesis of long chain polyunsaturated fatty acids in marine bacteria. We postulate that a mixed FAS/PKS and a hybrid NRPS/PKS assembly line each synthesize parts of the backbone that are linked together post-assembly in the case of zeamine and zeamine I. This interaction reflects a unique interplay between secondary lipid and secondary metabolite biosynthesis. Most likely, the zeamine antibiotics are produced as prodrugs that undergo activation in which a nonribosomal peptide sequence is cleaved off.