ATP in soil: A new extractant and extraction procedure

An extraction mixture comprised of 0.67 m H₃PO₄, 2 m urea, 20% DMSO, 1.8 mg of adenosine, 20 mM EDTA, and 1% Zwittergent 3,10 and a procedure to extract ATP from soil have been developed. The reagents and method were tested on six different Oklahoma soils and yielded a recovery of 99% of the ATP from added Escherichia coli cells. The extraction mixture was designed to minimize interference from soil-derived materials. The phosphoric acid provides acid to extract ATP and to inactivate proteins, and phosphate to saturate phosphate-binding sites. It also complexes or precipitates metal ions. The EDTA chelates metal ions, prevents inhibition of luciferase, and aids lysis of bacterial cells. The adenosine serves to saturate ATP binding-sites. Urea denatures proteins and prevents hydrogen bonding of the released ATP. DMSO, the Polytron treatment, and Zwittergent 3,10 remove cells from surfaces and lyse them. An internal standard of E. coli cells is used to determine efficiency of extraction and assay. When compared with the 12 best methods suggested by previous studies, the newly-formulated extractant and procedure yielded the greatest amount of ATP from soil.     

Extraction of bacterial lipopolysaccharides from soil samples and their determination using the Limulus amebocyte lysate reaction

Lipopolysaccharides were extracted from soil using an aqueous phenol procedure and determined by using the Limulus amebocyte lysate coagulation reaction. When heat-killed Escherichia coli cells were added to soil at a concentration of organisms expected to occur in subsurface material, there was a 10% recovery of the added cellular lipopolysaccharides (LPS); because of the sensitivity of the Limulus amebocyte lysate (LAL) reaction this recovery is sufficient for the method to be a rapid (4 h) estimate of the Gram-negative bacteria present in soil samples. By using a kinetic assay LPS could be measured over a concentration range of five orders of magnitude, which is important with environmental samples.     

Systemic antibacterial drug use in dogs in Australia

A survey of veterinarians' use of antibacterial drugs was conducted by distributing a questionnaire to Australian practitioners. Respondents were asked to indicate their general patterns of use of various systemic antibacterial drugs and drug combinations in dogs and their approach to certain specified clinical disorders. Overall, antibacterials of the p-lactam type (penicillins and cephalosporins) were most commonly used. Other antibacterials with substantial use were doxycycline, sulphonamide-trimethoprim, metronidazole, fluoroquinolones and clindamycin. Drug selection for different disorders was generally appropriate when compared with recommendations in recent texts, although inappropriate use was evident in some circumstances.