Microbial Urease

Seneca, Harry; Peer, P.; Nally, R.

doi:10.1038/1931106b0

Cited by 28 publications

(14 citation statements)

References 7 publications

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“…A large n u m b e r of micro-organisms including bacteria, actinomycetes and fungi can hydrolyse urea intracellularly 9 10 12 The urea molecules enter the bacterial cell where they are hydrolysed; very little urease is released extracellularly be viable metabolizing cells 10. In general, the ratio of ureolytic to non-ureolytic bacteria in soil remains constant, even though the total bacterial population may fluctuate considerably 9.…”

Section: Introductionmentioning

confidence: 99%

Urease activity in soils

1973

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Section: Introductionmentioning

confidence: 99%

Urease activity in soils

1973

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“…Table 1 shows that all lactobacilli failed to split urea; however, the sonic lysates are known to contain urease (12). There was no characteristic fermentation reaction.…”

Section: Resultsmentioning

confidence: 99%

Attempts to Grow Drug‐resistant Cultures of Lactobacilli for the Production of Yogurt

Seneca

Lattimer

Peer

1963

J American Geriatrics Society

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“…These are known to inhibit the activity of other ureases (Seneca et al, 1972;Sumner, 1951). Millimolar concentrations of magnesium or calcium ions had little or no effect on the activity even though they were in excess of Table 1.…”

Section: Resultsmentioning

confidence: 99%

Some Characteristics of Ureaplasma urealyticum. Urease Activity in a Simple Buffer: Effect of Metal Ions and Sulphydryl Inhibitors

Swanberg

Masover

Hayflick

1978

Journal of General Microbiology

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221Urealytic activity of the cytoplasmic fraction of Ureaplasma urealyticum prepared by digitonin lysis was assayed in a simple buffer system (HEPES plus EDTA) by measuring the release of I4CO2 from [l*C]urea. The K, of this preparation agreed with our previous observations of the same activity measured in a more complex reaction mixture. The substrate concentration at which maximum velocity occurred was approximately 20 mM. The activity was sensitive to heavy metals and inhibitors which react with sulphydryl groups such as N-ethylmaleimide and p-chloromercuribenzoate. It was not inhibited by Ca2+ or Mg2+ or by the reaction products, ammonia and carbon dioxide. I N T R O D U C T I O NThe ability to hydrolyse urea is given as the major differentiating characteristic of Ureaplasma urealyticum (Shepard et al., 1974). Recently, this urealytic activity was studied using a crude cytoplasmic preparation from U. urealyticum (Masover et al., 1976). The activity was shown to be soluble and not membrane-associated, a finding in agreement with those of others (Delisle, 1977; Furness & Cole, 1975; Vinther, 1976). Estimates of the pH and urea concentration optima were made, and the effects of several enzyme inhibitors were tested. However, it was apparent that a simpler reaction medium than the one used [a culture meaium (Basal Medium Eagle, BME) plus EDTA] was needed so that other requirements of U. urealyticum urealytic activity could be studied. Preliminary experiments (Masover et al., 1976) indicated that N-2-hydroxyethylpiperazine-N'-2-ethanesulphonic acid (HEPES) was satisfactory for such a system. Therefore we have studied U. urealyticum urealytic activity and several of its properties in this simpler reaction mixture. M E T H O D SOrganism and growth media. Ureaplasma urealyticum, serotype VIII (formerly T-strain 960), was originally supplied by M. C. Shepard (Camp Lejeune, N.C., U.S.A.) after being cloned eight times. It was passaged in our laboratory more than 30 times in medium without added urea, as previously described (Masover & Hayflick, 1973).The routine growth medium for T-strains has been described previously (

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Microbial Urease

Cited by 28 publications

References 7 publications

Urease activity in soils

Urease activity in soils

Attempts to Grow Drug‐resistant Cultures of Lactobacilli for the Production of Yogurt

Some Characteristics of Ureaplasma urealyticum. Urease Activity in a Simple Buffer: Effect of Metal Ions and Sulphydryl Inhibitors

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