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This is the first known report quantifying the concentration of Campylobacter spp. present in healthy adult horses in New Zealand. The presence of equine faecal material in water could elevate concentrations of faecal bacteria and therefore needs to be considered as a source of water contamination. The access of horses to waterways and coastal environments may also need to be restricted to prevent transmission of faecal indicator bacteria and potentially zoonotic agents.

The relative molal enthalpies of a series of pyrimidine compounds have been measured over a range of concentrations approaching the solubility limit in water at 25°. These measurements, when used in conjunction with the osmotic coefficient data of other workers, enable the evaluation of the enthalpy of self-In a previous study (Gill et al., 1967) we reported enthalpy results for the self-association of selected purine compounds. We have extended these measurements to a set of pyrimidine compounds where osmotic coefficient data are available (Ts'o et al., 1963;Ts'o and Chan, 1964). The theory of calculating the enthalpy of self-association from a combination of relative apparent molal enthalpy ( ) and the osmotic coefficient ( ) is discussed in the first paper. The basic assumption is that

Tracer studies of pyrimidine biosynthesis in Lactobacillus leichmannii (ATCC 7830) indicated that, while aspartate is utilized in the usual manner, the guanido carbon of arginine, rather than carbon dioxide, is utilized as a pyrimidine precursor. The guanido carbon of arginine also contributes, to some extent, to the carbon dioxide pool utilized for purine biosynthesis. The enzyme of the first reaction leading from arginine to pyrimidines, arginine deiminase, was investigated in crude bacterial extracts. It was inhibited by thymidylic acid and purine ribonucleotides, and to a lesser extent by purine deoxynucleotides and deoxycytidylic acid. Under the assay conditions employed, a number of nucleotides had no effect on the enzyme activity of the aspartate transcarbamylase of L. leichmannii. Growth of the cells in media containing uracil, compared to growth in media without uracil, resulted in a fourto fivefold decrease in the concentrations of aspartate transcarbamylase and dihydroorotase and a twofold increase in the concentration of arginine deiminase, as estimated from specific enzyme activity in crude extracts of the cells. A small increase in specific enzyme activity of ornithine transcarbamylase and carbamate kinase was also observed in extracts obtained from cells grown on uracil. No appreciable change in concentration of any of the five enzymes studied was detected when the cells were grown in media containing thymidine or guanylic acid. A hypothetical scheme which suggests a relationship between the control of purine and pyrimidine biosynthesis in this bacterium and which is consistent with the experimental results obtained is presented.

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Symposium on amino acid metabolism, Johns Hopkins Press, Baltimore, (1955) p. 124). The small amount of nitrate reductase enzyme formed by the uracil-requiring mutant in the absence of external uracil can probably be attributed to slight "turnover" of cell nucleic acids (Pardee, J. Bacteriol., 69, 233, 1955). In all cases it remains to be determined whether failure to synthesize inducible enzymes in the absence of specific amilao acids is due to requirement for the amino acid or to the deranged nucleic acid metabolism of the cells caused by the starvation procedure (Borek,

Ascorbate-2-sulfate sulfohydrolase (ascorbate sulfatase) has been purified 70 000-fold to homogeneity from bovine liver. The purification procedure consists of pH fractionation, ammonium sulfate fractionation, hydroxylapatite column chromatography, Sephadex A-50 column chromatography, and preparative ultracentrifugation. Gel electrophoresis and sieving columns show that the aggregation state of the enzyme is pH dependent. Arylsulfatase and ascorbate sulfatase activities of the homogeneous enzyme show the same banding pattern on gel electrophoresis. Gel electrophoresis in the presence of sodium dodecyl sulfate and 8 M urea shows that the enzyme is comprised of two protein species of 59 000 and 52 000 molecular weight. Both of these bands stain positively for glycoprotein. The enzyme also binds to concanavalin A-Sepharose. The most powerful inhibitor of ascorbate-2-sulfate sulfohydrolase is ascorbate 2-phosphate, followed by inorganic phosphate and the nucleotide triphosphates. Ascorbate 2sulfate hydrolysis is competitively inhibited by ascorbate 2phosphate, Na2HP04, and ^-nitrocatechol sulfate with K\ 2^.scorbate 2-sulfate was discovered in brine shrimp cysts in 1969 (Mead andFinamore, 1969). Soon after its discovery improved procedures were developed for synthesizing ascorbate 2-sulfate salts and for quantitating it from biological tissues (March, 1972;. Ascorbate 2-sulfate appears to be a ubiquitous substance in animals found in the urine or tissue of every species tested, including man (Mead and Finamore, 1969;March, 1972;Halver et al., 1975;Baker et al., 1971. The wide distribution of ascorbate 2-sulfate in animals suggests that this compound may play a role in ascorbic acid biochemistry. Ascorbate 2-sulfate is as effective as ascorbic acid in relieving scurvy in trout (Halver et al., 1975). Ascorbate 2-sulfate appears to be converted to ascorbic acid in vivo and ascorbic acid is converted to ascorbate 2-sulfate in primates (Baker et al., 1975). Therefore the enzymatic hydrolysis of ascorbate 2-sulfate to ascorbic acid should be a nutritionally important step in certain biological systems.Experiments were undertaken to isolate and characterize the enzyme activity which carries out the hydrolysis of ascorbate 2-sulfate to ascorbate.Preliminary results have shown that a crude bovine liver arylsulfatase A (EC 3.1.6.1) preparation hydrolyzes ascorbate 2-sulfate to ascorbate (Bullen, 1972). This enzyme activity was named ascorbate-2-sulfate sulfohydrolase (ascorbate sulfatase). It has been shown that ascorbate sulfatase activity is present in many tissues from several species of animals (Knight, 1974). More recently, the partial copurification and