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1.
J Inorg Biochem ; 159: 120-32, 2016 06.
Article in English | MEDLINE | ID: mdl-26986979

ABSTRACT

The complexes [Ag2(OOC-(CH2)n-COO)] (n=1-10) (1-10) were synthesised and reacted with 1,10-phenanthroline (phen) to yield derivatives formulating as [Ag2(phen)x(OOC-(CH2)y-COO)]·zH2O (x=2 or 3; y=1-10; z=1-4) (11-20) which are highly water-soluble and photo-stable in aqueous solution. The phen derivatives 11-20 exhibit chemotherapeutic potential against Candida albicans, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa and against cisplatin-sensitive breast (MCF-7) and resistant ovarian (SKOV-3) cancer cell lines. Cyclic voltammetric analysis and DNA binding and intercalation studies indicate that the mechanism of action of 11-20 is significantly different to that of their silver(I) dicarboxylate precursors and they do not induce DNA damage or ROS generation in mammalian cells. The representative complexes 9 and 19 (containing the undecanedioate ligand) were both found to significantly reduce superoxide and hydrogen peroxide induced oxidative stress in the yeast S. cerevisiae.


Subject(s)
Anti-Infective Agents , Antineoplastic Agents , Bacteria/growth & development , Breast Neoplasms/drug therapy , Candida albicans/growth & development , Ovarian Neoplasms/drug therapy , Phenanthrolines , Silver , Anti-Infective Agents/chemical synthesis , Anti-Infective Agents/chemistry , Anti-Infective Agents/pharmacology , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Female , Humans , Intercalating Agents/chemical synthesis , Intercalating Agents/chemistry , Intercalating Agents/pharmacology , MCF-7 Cells , Ovarian Neoplasms/metabolism , Ovarian Neoplasms/pathology , Phenanthrolines/chemical synthesis , Phenanthrolines/chemistry , Phenanthrolines/pharmacology , Saccharomyces cerevisiae/metabolism , Silver/chemistry , Silver/pharmacology , Solubility
2.
J Ind Microbiol Biotechnol ; 42(5): 799-806, 2015 May.
Article in English | MEDLINE | ID: mdl-25665503

ABSTRACT

Cunninghamella elegans is a fungus that has been used extensively as a microbial model of mammalian drug metabolism, whilst its potential as a biocatalyst for the preparative production of human drug metabolites has been often proposed, little effort has been made to enable this. Here, we describe a workflow for the application of C. elegans for the production of drug metabolites, starting from well-plate screening assays leading to the preparative production of drug metabolites using fungus immobilised either in alginate or as a biofilm. Using 12- and 96-well plates, the simultaneous screening of several drug biotransformations was achieved. To scale up the biotransformation, both modes of immobilisation enabled semi-continuous production of hydroxylated drug metabolites through repeated addition of drug and rejuvenation of the fungus. It was possible to improve the productivity in the biofilm culture for the production of 4'-hydroxydiclofenac from 1 mg/l h to over 4 mg/l h by reducing the incubation time for biotransformation and the number of rejuvenation steps.


Subject(s)
Bioreactors , Cunninghamella/metabolism , Pharmaceutical Preparations/analysis , Pharmaceutical Preparations/metabolism , Alginates , Biofilms , Biotransformation , Cells, Immobilized/metabolism , Diclofenac/analogs & derivatives , Diclofenac/metabolism , Glucuronic Acid , Hexuronic Acids , Pharmaceutical Preparations/isolation & purification , Time Factors
3.
J Food Prot ; 72(7): 1450-6, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19681268

ABSTRACT

Listeria monocytogenes is a potentially lethal foodborne pathogen commonly found in the environment. European Union hygiene legislation places responsibility for safety on primary production facilities, including farms, as part of a policy to introduce traceability throughout the food chain. This study aimed to determine the occurrence of L. monocytogenes in the Irish dairy farm environment and in particular the milking facility. Two hundred ninety-eight environmental samples were collected from 16 farms in the southern region of Ireland. A number of farms within the group supply raw milk to the unpasteurized milk cheese industry. The samples taken included cow feces, milk, silage, soil, water, etc. Samples were enriched in Listeria enrichment broth and incubated for 48 h, followed by plating on chromogenic agar Listeria Ottavani & Agosti and further incubation of the plates for 24 to 48 h. Presumptive L. monocytogenes isolates were purified and confirmed by PCR targeting the hly gene. Overall, 19% of the samples (57 of 298) were positive for L. monocytogenes. These were serotyped using conventional and PCR methods; serotypes 1/2a, 1/2b, and 4b made up 78% of the typeable isolates. A correlation was found between the level of hygiene standards on the farm and the occurrence of L. monocytogenes. There was little difference in the occurrence of L. monocytogenes between farms supplying milk to the unpasteurized milk cheese industry and those supplying milk for processing. This study demonstrates the prevalence of L. monocytogenes in the dairy farm environment and the need for good hygiene practices to prevent its entry into the food chain.


Subject(s)
Dairying/standards , Environmental Microbiology , Food Contamination/prevention & control , Hygiene , Listeria monocytogenes/isolation & purification , Animal Feed/microbiology , Animals , Cattle , Consumer Product Safety , Equipment Contamination/prevention & control , Feces/microbiology , Female , Floors and Floorcoverings , Food Contamination/analysis , Ireland , Milk/microbiology , Soil Microbiology , Water Microbiology
4.
Microbiology (Reading) ; 151(Pt 4): 1301-1311, 2005 Apr.
Article in English | MEDLINE | ID: mdl-15817797

ABSTRACT

The serotype F phage Phi42 of Staphylococcus aureus is a triple-converting bacteriophage that encodes the staphylokinase gene (sak) and the enterotoxin A gene (entA). Lysogeny results in loss of expression of the chromosomal beta-haemolysin gene (hlb) (negative conversion), the expression of staphylokinase and enterotoxin A (positive conversion), and the acquisition of resistance to lysis by all 23 phages of the International Basic Set (IBS) of S. aureus typing phages. Until this study, the basis of Phi42 resistance to lysis by exogenous phages was unknown. The authors report here that phage Phi42 encodes a restriction-modification (R-M) system, termed Sau42I, adjacent to and in the same orientation to the phage integrase gene int. The genes encoding Sau42I were cloned and sequenced, and found to consist of two overlapping reading frames, ORF S (specificity) and ORF RM (restriction-modification), in the same orientation. The ORFs share a high degree of DNA and amino acid sequence homology with the previously characterized BcgI R-M system of Bacillus coagulans. Expression of the cloned Sau42I ORF S and ORF RM in S. aureus 80CR3 transformants from a plasmid vector conferred resistance to lysis by all 23 IBS phages. Similarly, transformants of S. aureus RN4220 harbouring recombinant plasmids containing both ORFs were resistant to lysis by the IBS typing phages. However, transformants harbouring plasmids encoding either ORF S or ORF RM were susceptible to lysis by the IBS phages, and they had the same phage-susceptibility pattern as the respective parental isolates. In vitro analysis of crude and partially purified extracts of S. aureus transformants harbouring both the Phi42 ORF S and ORF RM genes indicated that Sau42I has endonuclease activity and requires co-factors Mg(2+) and S-adenosylmethionine in order to function, and activity is optimized at pH 8, although the precise recognition sequence has yet to be determined. The findings of this study confirm that Phi42 is a quadruple-converting phage, believed to be the first described for S. aureus, and show that it encodes a novel R-M system termed Sau42I.


Subject(s)
DNA Restriction-Modification Enzymes/genetics , DNA Restriction-Modification Enzymes/metabolism , Staphylococcus Phages/genetics , Staphylococcus Phages/metabolism , Amino Acid Sequence , Chromosome Mapping , Cloning, Molecular , Escherichia coli/genetics , Genes, Viral , Lysogeny , Molecular Sequence Data , Open Reading Frames , Phenotype , Sequence Homology, Amino Acid , Staphylococcus Phages/classification , Staphylococcus aureus/virology
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