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Biomedical subjects

N Romano

Publications and source records attributed to N Romano.

At least 73 records · Page 4Linked to original sources
PubMed1977

Immunological analysis of plasma membranes of a T-strain of mycoplasma (Ureaplasma urealyticum).

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 inhibition and complement fixation tests. After a further centrifugation at 100,000 X g, the immunogenic activity of the soluble fraction was completely lost. Immunogenic determinants in mycoplasma membranes could also be demonstrated by adsorption tests; cell membranes were more effective than soluble fractions in adsorbing antibody capacity from the immune sera against whole cells. It has been shown by further experiments that cell membranes have at least two major antigenic determinants, which differ either in chemical nature or in capacity to adsorb and evoke antibodies, characterized by different serological behaviors.

Adsorption↗
PubMed1977

L-histidine ammonia-lyase from a T-strain Mycoplasma (Ureaplasma urealyticum).

L-histidine ammonia-lyase (E.C. 4.3.1.3) activity was shown to occur in cell-free extracts of Ureaplasma urealyticum. The activity of the crude enzyme depends on the presence of thiol compounds. However, higher than optimal concentrations of reduced glutathione, were shown to cause some inhibition of enzyme activity. This enzymatic reaction is characterized by a "lag" phase, whose duration depends on assay conditions. The substrate saturation curve shows a sigmoidal pattern probably due to the presence (in crude enzyme preparations) of some inhibiting impurity which reversibly combines with the substrate. Statistically significant increases of enzyme activity were demonstrated in crude enzyme preparations obtained from mycoplasma cells grown in broth medium supplemented with 16 mM L-histidine.

Ammonia-Lyases↗
PubMed1976

Biosynthesis of saturated and unsaturated fatty acids by a T-strain mycoplasma (Ureaplasma).

A human T mycoplasma (Ureaplasma urealyticum) incorporated radioactivity into its lipids from [1-14C]acetate in the growth medium. Methanolysis of the lipids showed the label to be confined almost entirely to the methyl esters of the fatty acids. About 80% of the label was associated with the methyl esters of the saturated fatty acids, and the rest was found in the unsaturated methyl ester fraction. Gas-liquid chromatography of the saturated methyl esters showed the label to be present in the peaks of palmitate, myristate, and stearate, whereas in the unsaturated methyl ester fraction most of the radioactivity emerged in the peak of palmitoleate. The addition of either oleic or palmitic acid to the growth medium markedly decreased the organisms' incorporation of radioactivity from acetate. It is concluded that the T mycoplasma strain is capable of de novo synthesis of both saturated and unsaturated fatty acids, in this respect differing from all of the Mycoplasma and Acholeplasma strains investigated to date.

Acetates↗
PubMed1976

Mycoplasmas in pregnant women and in newborn infants.

Mycoplasmas were isolated from 96 of 143 vaginal swabs of pregnant women on their first visit at the Prenatal Center. Ureaplasmas alone were isolated in a higher percentage than M. hominis alone or combination with Ureaplasmas. The isolated cultures at 36 weeks of gestation show no significant difference with the first visit isolation. Colonization of mycoplasmas were found in a higher percentage (93.3%) in the abnormal deliveries than in normal ones. Mycoplasmas were isolated also from throat swabs of 19 out of 141 newborn infants: the proportion of mycoplasmas positive infants was higher in low birth, weight children.

Birth Weight↗
PubMed1975

Effect of L-histidine on the survival of a T-strain of mycoplasma.

The addition of L-histidine to the growth medium prolongs the stationary phase and the survival of a T-strain of mycoplasma. Results of an experiment performed with (14)C-labeled urea demonstrate that the action of L-histidine is based on the retardation of the rise of pH.

Buffers↗
PubMed1974

Serological activity of lipids of a T strain of Mycoplasma.

Complement-fixing activity of a T strain of Mycoplasma was found to be associated with its lipid components. Heat stability and lability of periodate and beta-glucosidase treatments led to the conclusion that complement-fixing, active lipids had carboydrate determinants. Periodate treatment of chromatographic fractions of a chloroform-methanol extract showed that only antigens contained in the acetone fraction were periodate labile. Lipids also appeared to be involved in the passive hemagglutination, since the lipid fraction active in complement fixation also combined and blocked the action of antibodies which agglutinated sensitized erythrocytes with strain P108.

Acetone↗
PubMed1972

Lipids of a T strain of Mycoplasma.

Cholesterol, free fatty acids, and phosphatidic acid are the predominant lipids of a T strain of Mycoplasma. The remaining neutral lipids are composed of cholesteryl esters, triglycerides, and diglycerides. Three glucose-containing glycolipids are present in trace amounts. In addition to phosphatidic acid, the phospholipids are comprised of phosphatidyl glycerol, diphosphatidyl glycerol, and phosphatidyl ethanolamine. Another polar lipid was found to be ninhydrin-positive and phosphate-free. It appears to be a diamino hydroxy compound containing adjacent fatty acid ester and N-acyl groups.

Autoradiography↗