Showing papers on "Ribostamycin published in 2014"

Ribostamycin sulfate composition freeze-dried powder for injection

Abstract: The invention provides a ribostamycin sulfate composition freeze-dried powder for injection, and belongs to the field of medicine and medicine preparation technology. The ribostamycin sulfate composition freeze-dried powder comprises following raw material ingredients, by weight, 7.26 to 9.17 parts of ribostamycin sulfate, 5.25 to 7.21 parts of chitosan nanoparticle, and 81.34 to 87.10 parts of injection water. Advantages of the ribostamycin sulfate composition freeze-dried powder are that: 1) kidney damage caused by the ribostamycin sulfate composition made from ribostamycin sulfate and the chitosan nanoparticle is reduced significantly; 2) antibacterial activity spectrum is wider, antibacterial activities on mycobacterium tuberculosis and streptococcus are increased greatly; 3) improvement of activities is capable of shortening medication cycle of patients, and reducing occurrence likelihood of adverse reaction caused by accumulation of ribostamycin sulfate; and 4) the chitosan nanoparticle can be used as a freeze-dried skeleton agent of the freeze-dried powder injection instead of mannitol so as to avoid active effects of mannitol on human bodies.

Identification of Genes Putatively Involved in the Biosynthesis of Antitubercular Peptide in Streptomyces ribosidificus NRRL B-11466

Abstract: Aims: To determine the potential antitubercular activity of Streptomyces ribosidificus NRRL B-11466 both on genotypic and phenotypic levels. Methodology: Standard methods and software programs were used for nucleotide/protein sequence analysis and phenotypic detection of antitubercular activity. Results: Analysis of the submitted DNA segment (accession code = AJ744850) harbouring the ribostamycin biosynthetic gene cluster showed that the respective gene cluster was flanked in the upstream region by three open reading frames (ORFs), encoding putative type II thioesterase (SribL03.14c) and two nonribosomal peptide synthases (SribL03.14c and SribL03.14c). These ORFs were of high amino acid similarities (about 80%) to those located in the viomycin and related antibiotic biosynthetic gene clusters. A DNA segment harbouring three ORFs, putatively involved in Original Research Article British Biotechnology Journal, 4(1): 40-50, 2014 41 capreomycidine biosynthesis was submitted into the GenBank database under the accession code HQ327309. Comparative analysis of the respective DNA segment with viomycin and related antibiotic biosynthetic gene clusters showed: firstly, location of the respective DNA segment in the neighbourhood and upstream to the ribostamycine biosynthetic gene cluster; secondly, conservation of six ORFs: SriC (putative L-arginine hydroxylase); SriD (putative L-capreomycidine synthase), SriE (putative permease) located on our submitted DNA fragment; and SribL03.14c, SribL03.15c, SribL03.16c located on the DNA fragment harboring ribostamycin biosynthetic gene cluster, among the tested biosynthetic gene clusters. Phenotypically, S. ribosodificus inhibited growth of Mycobacterium smegmatis ATCC 19420 and Mycobacterium phlei ATCC 11758. Conclusion: Streptomyces ribosidificus NRRL B-11466 produces antimycobacterial agents and this was confirmed genotypically via detection of 6 ORFs with high amino acid similarities (about 80%) to those located in the viomycin and related antibiotic biosynthetic gene clusters as well as phenotypically by determining its inhibitory activity against Mycobacterium smegmatis ATCC 19420. This is the first report about identification of genes putatively involved capreomycidine biosynthesis in Streptomyces ribosidificus NRRL B-11466.

Isolation, heterologous expression and gene duplication of certain ribostamycin biosynthetic genes from Streptomyces ribosidificus NRRL B-11466

Abstract: Background To elucidate the biosynthetic pathways of ribostamycin and related antibiotics, cloning, expression and functional determination of certain genes out of the respective gene clusters have to be carried out. Methods and findings Analysis of the respective antibiotic biosynthetic gene clusters showed that the RibN protein had a remarkable difference in its primary structure relative to NeoN, ParN, and LivN homologous proteins. In this study, the ribC from the ribostamycin biosynthetic gene cluster of Streptomyces ribosidificus NRRL B-11466, and the parN gene from the paromomycin biosynthetic gene cluster of Streptomyces rimosus subsp. paromomycinus NRRL 2455 were amplified using PCR, cloned into the cloning plasmid pUCPU21 producing pURC and pURCPN recombinant plasmids, respectively. RibC protein was expressed in E. coli JM109(DE3) under the control of T7 promoter. The expressed RibC protein was analyzed and shown to produce the functional protein 2-deoxy-scyllo-inosose synthase which catalyses the formation 2-deoxy-scyllo-inosose from glucose-6-phosphate. Alignment of RibN and its homologous proteins revealed a stretch of nonconserved amino acid sequence was detected at the positions from 185 to 261 in the RibN amino acid sequence as determined by multiple amino acid alignment sequences. Both ribC and parN were cloned into pUWL201PW shuttle vector producing pUWRC and pUWPN, respectively. The resulted recombinant plasmids were transformed into S. ribosidificus for the purpose of gene duplication and studying their influence on ribostamycin production. Conclusion RibC was successfully cloned, heterologous expressed in E. coli. The produced protein was biochemically proved to be involved in the synthesis of 2-deoxy-scyllo-inosose from Glucose-6-p. RibN was proved to have endogenous frame-shift mutation which was proposed to be reason for formation of ribostamycin as an end product. RibN was cloned into pUWL201PW shuttle vector as a prerequisite step for its influence on ribostamycin production.

Aminoglycosides Suppress the Protein Folding Activity of the Molecular Chaperone HSC70: Implication of a Structure-Activity Relationship

Abstract: Background: The mechanism of aminoglycoside (AG)-induced nephrotoxicity has not been fully elucidated. We previously reported that gentamicin suppresses the functions of HSC70, a heat shock cognate protein, which is a cytosolic molecular chaperone in mammalian cells. However, the relationship between HSC70 dysfunction and nephrotoxicity has not been clarified yet. Methods: The effects of 11 AGs, including gentamicin, on the function, protein refolding and substrate binding of HSC70 were examined in vitro. The protein refolding activity of HSC70 was examined by enzymatic activity restoration of the denatured firefly luciferase. Substrate binding activity of HSC70 was examined by the binding of fluorescent-dye-labeled reduced carboxymethlylated α-lactalbumin determined by HSC70/substrate complex formation by native polyacrylamide gel electrophoresis. Results: Strong inhibitory activity of AGs on the protein refolding activity of HSC70 was observed for arbekacin, gentamicin, neomycin and sisomicin, but not spectinomycin, streptomycin, ribostamycin and paromomycin, and inhibition was weak for tobramycin, amikacin and kanamycin. Neomycin strongly suppressed the formation of the HSC70/substrate complex and had the lowest concentration that resulted in 50% inhibition (IC50; in the order of 10-4M). Arbekacin, gentamicin, sisomicin and tobramycin had IC50 values in the order of 10-3M. Amikacin, ribostamycin and paromomycin had no effective potencies. Conclusions: The inhibition efficacies of AGs for protein refolding of HSC70 were as follows: neomycin >> gentamicin, arbekacin, and sisomicin > tobramycin, amikacin and kanamycin > spectinomycin, streptomycin, ribostamycin and paromomycin. Amino groups and/or hydroxyl groups located at 2′, 3′, 4′, and 6′ of amino sugar residue II, as well as the number of amino sugar rings were closely associated with the inhibition efficacies of AGs. Inhibition efficacies of AGs towards the function of HSC70 correlated well with the nephrotoxicity of AGs deduced from the in vivo studies previously reported. Amino groups/hydroxyl groups and the number of amino sugar rings of AGs were shown to be important for inhibition efficacies. The results strongly suggest that the AG-induced dysfunction of HSC70 is involved in the nephrotoxicity.