Total Chemical Syntheses of the GM and F-GM Ganglioside Epitopes and Comparative Pre-Clinical Evaluation for Non-Invasive Imaging of Oligodendrocyte Differentiation.

Gangliosides are intimately involved in a plenum of (neuro)inflammatory processes, yet progress in establishing structure-function interplay is frequently hindered by the availability of well-defined glycostructures. Motivated by the ubiquity of the ganglioside GM in chemical neurology, and in particular by its conspicuous presence in myelin, the GM epitope was examined with a view to preclinical validation as a tracer. The suitability of this scaffold for the noninvasive imaging of oligodendrocyte differentiation in Multiple sclerosis is disclosed.

Single Site Fluorination of the GM Ganglioside Epitope Upregulates Oligodendrocyte Differentiation.

Relapsing multiple sclerosis is synonymous with demyelination, and thus, suppressing and or reversing this process is of paramount clinical significance. While insulating myelin sheath has a large lipid composition (ca. 70-80%), it also has a characteristically large composition of the sialosylgalactosylceramide gangliosde GM present.

A novel DNA modification by sulphur.

Streptomyces lividans has a novel DNA modification, which sensitises its DNA to degradation during electrophoresis (the Dnd phenotype). The entire gene cluster (dnd) involved in this modification was localized on an 8 kb DNA fragment and was expressed in a S. lividans deletion mutant (dnd) and in several heterologous hosts.

Streptomyces coelicolor A3(2) lacks a genomic island present in the chromosome of Streptomyces lividans 66.

Streptomyces lividans ZX1 has become a preferred host for DNA cloning in Streptomyces species over its progenitor, the wild-type strain 66 (stock number 1326 from the John Innes Center collection), especially when stable DNA is crucial for in vitro electrophoresis, because DNA from strain 66 contains a novel modification that makes it sensitive to oxidative double-strand cleavage during electrophoresis. Detailed analysis of this modification-deficient mutant (ZX1) revealed that it has several additional phenotypic traits associated with a chromosomal deletion of ca. 90 kb, which was cloned and mapped by using a cosmid library.

NAD+-dependent DNA ligases of Mycobacterium tuberculosis and Streptomyces coelicolor.

Sequencing of the genomes of Mycobacterium tuberculosis H37Rv and Streptomyces coelicolor A3(2) identified putative genes for an NAD(+)-dependent DNA ligase. We have cloned both open reading frames and overexpressed the protein products in Escherichia coli. In vitro biochemical assays confirm that each of these proteins encodes a functional DNA ligase that uses NAD(+) as its cofactor.

Streptomyces coelicolor A3(2) plasmid SCP2*: deductions from the complete sequence.

Plasmid SCP2* is a 31 kb, circular, low-copy-number plasmid originally identified in Streptomyces coelicolor A3(2) as a fertility factor. The plasmid was completely sequenced. The analysis of the 31 317 bp sequence revealed 34 ORFs encoding putative proteins from 31 to 710 aa long, most of them lacking similarity to known proteins.

PCR-targeted Streptomyces gene replacement identifies a protein domain needed for biosynthesis of the sesquiterpene soil odor geosmin.

Streptomycetes are high G+C Gram-positive, antibiotic-producing, mycelial soil bacteria. The 8.7-Mb Streptomyces coelicolor genome was previously sequenced by using an ordered library of Supercos-1 clones.

[Construction of a temperature inducible shuttle expression vector and its application in Streptomyces].

pHZ1080, an E. coli-Streptomyces shuttle expression vector was constructed in order to explore the utilization of lambda phage regulated expression elements in Streptomyces. A 2.

Azole antifungals are potent inhibitors of cytochrome P450 mono-oxygenases and bacterial growth in mycobacteria and streptomycetes.

The genome sequence of Mycobacterium tuberculosis has revealed the presence of 20 different cytochrome P450 mono-oxygenases (P450s) within this organism, and subsequent genome sequences of other mycobacteria and of Streptomyces coelicolor have indicated that these actinomycetes also have large complements of P450s, pointing to important physiological roles for these enzymes. The actinomycete P450s include homologues of 14alpha-sterol demethylases, the targets for the azole class of drugs in yeast and fungi. Previously, this type of P450 was considered to be absent from bacteria.

Sterol 14alpha-demethylase activity in Streptomyces coelicolor A3(2) is associated with an unusual member of the CYP51 gene family.

The annotation of the genome sequence of Streptomyces coelicolor A3(2) revealed a cytochrome P450 (CYP) resembling various sterol 14alpha-demethylases (CYP51). The putative CYP open reading frame (SC7E4.20) was cloned with a tetrahistidine tag appended to the C-terminus and expressed in Escherichia coli.

Plasmid transfer from Streptomyces to Mycobacterium smegmatis by spontaneous transformation.

Hybrids of the Streptomyces coelicolor conjugative plasmid SCP2* and the Mycobacterium plasmid pAL5000 were transferred from Streptomyces coelicolor or Streptomyces lividans to Mycobacterium smegmatis mc2155 in plate crosses. Inactivation of the SCP2* transfer function did not prevent or reduce plasmid transfer. This transfer was DNase I sensitive and thus involved release of DNA from Streptomyces, followed by transformation of M.

'Streptomyces nanchangensis', a producer of the insecticidal polyether antibiotic nanchangmycin and the antiparasitic macrolide meilingmycin, contains multiple polyketide gene clusters.

Several independent gene clusters containing varying lengths of type I polyketide synthase genes were isolated from 'Streptomyces nanchangensis' NS3226, a producer of nanchangmycin and meilingmycin. The former is a polyether compound similar to dianemycin and the latter is a macrolide compound similar to milbemycin, which shares the same macrolide ring as avermectin but has different side groups. Clusters A-H spanned about 133, 132, 104, 174, 122, 54, 37 and 59 kb, respectively.

Transposition of Tn4560 of Streptomyces fradiae in Mycobacterium smegmatis.

Tn4560 (8.6 kb) was derived from Tn4556, a Tn3-like element from Streptomyces fradiae. It contains a viomycin resistance gene that has not been used previously for selection in mycobacteria.

Transposition of IS117 of Streptomyces coelicolor A3(2) in Mycobacterium smegmatis.

Derivatives of IS117, the Streptomyces coelicolor A3(2) 2.6 kb minicircle, transpose efficiently in Mycobacterium smegmatis, targeting chromosomal sites resembling translation start signals. Two IS117 derivatives, pIJ4696 and pIJ4697, containing a Streptomyces hygromycin-resistance gene in opposite orientations were introduced into M.