ABSTRACT
The aim of this work was to investigate the effectiveness of a high voltage multi-spark electric discharge, with pulse energy of 1 Joule, in killing microorganisms in wastewater. Wastewater from primary treated effluent arising from domestic and industrial sources was abstracted for continuous pulsed discharge disinfection. The wastewater contained a large mixed population of microorganisms (approximately 10(7) CFU ml(-1) [10(9) CFU 100 ml(-1)] total aerobic heterotrophic bacteria) including vegetative cells and spores. The electrical conductivity of the wastewater ranged from 900-1400 microS cm(-1) and it was shown that a specific energy of 1.25-1.5 J cm(-3) was required to achieve 1 log reduction in bacterial (faecal coliforms/total aerobic heterotrophs) content. This is higher than that previously shown to reduce the population of E. coli in tap water of low conductivity, demonstrating the role of total wastewater constituents, including dissolved and particulate substances, water colour and the presence of microbial spores, in effective disinfection. The system can be engineered to eradicate microbial populations to levels governed by legislation by increasing treatment time or energy input.
Subject(s)
Disinfection/methods , Electricity , Industrial Waste , Waste Disposal, Fluid/methods , Water Purification/methods , Bacteria/pathogenicity , Escherichia coli/pathogenicity , Spores, Bacterial/pathogenicity , Water MicrobiologyABSTRACT
AIMS: To examine the use of a novel multielectrode slipping surface discharge (SSD) treatment system, capable of pulsed plasma discharge directly in water, in killing micro-organisms. METHODS AND RESULTS: Potable water containing Escherichia coli and somatic coliphages was treated with pulsed electric discharges generated by the SSD. The SSD system was highly efficient in the microbial disinfection of water with a low energy utilization (eta approximately 10-4 kW h l-1). CONCLUSIONS: The SSD treatment was effective in the destruction of E. coli and its coliphages through the generation of u.v. radiation, ozone and free radicals. SIGNIFICANCE AND IMPACT OF THE STUDY: The non-thermal treatment method can be used for the eradication of micro-organisms in a range of contaminated liquids, including milk, negating the use of pasteurization. The method utilizes multipoint electric discharges capable of treating large volumes of liquid under static and flowing regimes.
Subject(s)
Disinfection , Water Microbiology , Coliphages/growth & development , Electricity , Electrodes , Escherichia coli/growth & development , Hydrogen-Ion Concentration , Ions , Models, StructuralABSTRACT
A new phosphorylating agent for nucleosides, 2-O-(4,4'-dimethoxytrityl) ethylsulfonylethan-2'-yl-phosphate (1), has been developed by us. In the many examples studied by us, phosphorylation yields were found to be very high (about 90%). The procedure appears to be remarkably general and can be utilized for the phosphorylation of many biomolecules. Successful application of this phosphorylation method has contributed to the discovery of inhibitors of HIV integrase in our laboratory.
Subject(s)
HIV Integrase Inhibitors/chemical synthesis , Nucleosides/chemistry , Nucleosides/chemical synthesis , Organophosphorus Compounds/chemistry , HIV Integrase Inhibitors/pharmacology , Nucleosides/pharmacology , PhosphorylationABSTRACT
Integration of HIV viral DNA into human chromosomal DNA catalyzed by HIV integrase is essential for the replication of HIV. Discovery of novel inhibitors of HIV integrase is of considerable significance in approaches to the development of therapeutic agents against AIDS. We have synthesized a new dinucleotide 1 with an internucleotide phosphate bond that is unusually resistant to exonucleases. This compound exhibits potent anti-HIV-1 integrase activity.
Subject(s)
Exonucleases/metabolism , HIV Integrase Inhibitors/pharmacology , HIV Integrase/metabolism , Nucleotides/pharmacology , DNA, Viral/metabolism , HIV Integrase/drug effects , HIV Integrase Inhibitors/chemical synthesis , HIV Integrase Inhibitors/chemistry , HIV Integrase Inhibitors/metabolism , Kinetics , Molecular Conformation , Nucleotides/chemical synthesis , Nucleotides/chemistryABSTRACT
The viral enzyme, HIV integrase, is involved in the integration of viral DNA into host cell DNA. In the quest for a small nucleotide system with nuclease stability of the internucleotide phosphate bond and critical structural features for recognition and inhibition of HIV-1 integrase, we have discovered a conceptually novel dinucleotide, pIsodApdC, which is a potent inhibitor of this key viral enzyme.
Subject(s)
HIV Integrase Inhibitors/metabolism , HIV Integrase/metabolism , Nucleotides/metabolism , HIV Integrase Inhibitors/pharmacologyABSTRACT
Reactivity of the amide-lactam function of nucleic bases under various conditions, methods of its activation, protection, deprotection and modification have been considered. Expediency of the function's protection in oligonucleotide synthesis is discussed.
Subject(s)
Amides/chemistry , Lactams/chemistry , Nucleic Acids/chemistry , Alkylating Agents , Base Sequence , Molecular Sequence Data , Oligodeoxyribonucleotides , PhosphorylationABSTRACT
A series of self-complementary decadeoxynucleotides containing a native or modified HaeIII site GGCC (with one or both guanine residues 6-O-cetylated) have been synthesized by the phosphotriester approach. The nonmodified decanucleotide is normally digested with snake venom phosphodiesterase as well as with HaeIII and BspI restriction endonucleases, whereas the bulky 6-O-alkyl substituent strongly inhibits the VPDE hydrolysis and completely prevents digestion with the endonucleases.
