R La Licata

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Ureaplasma urealyticum lacks the conventional mechanisms for adenosine 5-triphosphate (ATP) generation, such as glycolysis or arginine breakdown, present in other mycoplasmas. The possibility that ATP may be generated in these organisms through the formation of an ion gradient coupled to urea hydrolysis has been suggested by Masover and Hayflick (Ann NY(More)
The effects of various reaction conditions and the influence of urea and its hydrolysis products on Ureaplasma ATP synthesis were assayed using of a pH stat system which avoids the unfavourable changes of the external pH. The results proved that ATP synthesis required the presence of an optimal phosphate concentration and was dependent on the urea content(More)
Although considerable attention has been devoted to the urea-hydrolyzing activity of Ureaplasma urealyticum, there is as yet no firmly established function for this enzyme. Present results support the idea that its activity generates a chemical gradient across the membrane which drives adenosine 5'-triphosphate synthesis through a chemiosmotic type of(More)
The localization of some enzymic activities in cell fractions of Ureaplasma urealyticum was studied. A quantitative evaluation of the effectiveness of several cell lysis procedures was obtained by using labeled membranes and sucrose density gradient centrifugation. Ultrasonic treatment was found to be the most effective procedure for lysing the cells,(More)
Adenosine triphosphatase activity of U. urealyticum is an integral membrane-bound protein which cannot be detached from the membrane by mild treatment with EDTA in low-ionic strength media nor by ionic detergents which rapidly inactivated the enzyme. The enzyme was Mg++ dependent; Mn++ and Co++ could replace Mg++ to some extent. A slight stimulatory effect(More)
The cell membranes of a T-strain of mycoplasma, obtained by ultrasonic disruption, were as effective as whole organisms in eliciting metabolism-inhibiting and complement-fixing antibodies. The soluble fraction separated from cell membranes by centrifugation at 35,000 X g showed a minor ability to elicit an antibody response as measured by metabolism(More)
A seroepidemiological survey was carried out with the aim of establishing whether or not HIV 2 infection could be detected in Western Sicily. Two groups of sera were tested by EIA and WB assay against HIV 1 and HIV 2. 200 sera taken from North African immigrants in the Mazara del Vallo area, and 297 samples taken from AIDS-high risk groups individuals(More)
A cross-sectional seroepidemiologic study was carried out between 1985 and 1990 in 1,567 heterosexual intravenous drug users who had been seen at the AIDS Regional Reference Center in Palermo, Italy, to evaluate the rate of human immunodeficiency virus type 1 (HIV-1) seroprevalence in this group and its long-term trend. Sixty serum samples collected from(More)
Epidemiological surveillance of influenza was carried out in Palermo betwen 1970 and 1975. Antigenic structure of viral strains A/H3N2 isolated from influenza patients during winter outbreaks was studied in comparison with reference strains circulating in the same periods in other parts of the world. Antigenic drift of hemagglutinin, of neuraminidase, or of(More)
731 serum samples were drawn from inhabitants of Favignana (Egadi Islands, total population 3,000). Presence of HBsAg and anti HBs was tested by R.I.A. Although only two cases of B Virus Hepatitis had been observed in the last 3 years, the overall positivity for HBsAg was 4.8% and for anti HBs 31.6%, showing a distribution by age and sex comparable to that(More)