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Biomedical subjects

E Gulletta

Publications and source records attributed to E Gulletta.

32 records · Page 2Linked to original sources
PubMed1983

The pleiotropic ts15 mutation of E. coli is an IS1 insertion in the rho structural gene.

Rho protein regulates transcription termination in E. coli. Some of the temperature-sensitive mutants defective in Rho protein, e.g., ts15, show remarkable pleiotropic phenotypes. The ts mutations map between the ilv and cya loci on the E. coli chromosome. We have cloned the gene that restores the wild-type phenotypes of these mutants. Genetic and biochemical characterizations have shown that the cloned DNA segment carries the structural gene for the Rho polypeptide. Analysis of the rhots15 mutation has revealed the presence of an IS1 insertion in the carboxy terminal segment of the rho cistron, thereby truncating the 52-kilodalton (kd) Rho polypeptide to a 50-kd size and also making it thermolabile. This provides an example of how an IS1 insertion mutation can cause a TS phenotype. We have also shown that the multiple phenotypes of the mutant cell, including the temperature sensitivity, are caused by a single mutation (rhots15::IS1) in the rho structural gene. How a rho structural gene mutation may cause such pleiotropy is discussed.

Bacterial Proteins↗
PubMed1982

Cloning of the RHO gene of Escherichia coli.

The map position of the rho gene on E coil chromosome, as determined by phage P1 generalized transduction, was determined. The gene order is ilv-rho-cya. By Hind III endonuclease shotgun technique, the rho+ gene was cloned into a lambda-Charon 25 vector. The sizing of the restriction endonuclease generated DNA fragments by agarose gel electrophoresis, the heteroduplex analysis of cloned DNA molecules by electron microscope and the demonstration of the synthesis of rho protein by the cloned DNA shows that a functional piece of DNA, containing the entire rho gene of E coli has been cloned.

Bacteriophage lambda↗
PubMed1978

[Guanyl cyclase in Escherichia coli. II. Identification and characteristics on the enzyme inhibitor].

The activity of guanylate cyclase and that of its inhibitor present in E. coli extract, have been separated through a linear KCl gradient on DEAE-cellulose column. The activity of the inhibitor is lost after ribonuclease treatment, whereas is strengthened by addition of poly (C). Other types of RNA synthetic homopolymers do not affect the inhibitor's activity. Chromatographic analysis of the products of guanylate cyclase measured in the presence of FI and FI plus poly (C), indicated that the inhibitor has a poly (C) dependent GTPase activity.

Deoxyribonucleases↗
PubMed1978

[Guanylate cyclase in E. coli. III. Purification and possible physiological role of GTPase].

A phosphohydrolase with a preferential activity for GTP has been isolated and partially purified from E. coli extracts. The enzyme purification has been achieved through precipitation by ammonium sulfate and chromatography on DEAE-cellulose, DEAE-Sephadex, Ultragel and a second DEAE-cellulose column. The phosphohydrolase activity is poly (C) dependent. The chromatographic analysis on PEI-cellulose has shown that the main product of GTP hydrolysis is GDP. The possibility that the enzyme partially purified in this work has an important role in the control of GTP availability as substrate for guanylate cyclase into the cells has been discussed.

Chromatography, DEAE-Cellulose↗
PubMedDate not supplied

A serological study of mycobacterial infections in AIDS and HIV-1 positive patients.

The Authors have tested the new Tb-Elisa method to detect specific antibodies, raised against A60 major mycobacterial antigen complex, in patients of groups II, III and IV of CDC classification suffering from acquired immunodeficiency and in HIV-1 negative control subjects. The test results support laboratory diagnosis of acute phase and reactivation of mycobacterial infection.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Rapid detection of human cytomegalovirus in immunocompromised patients.

The Authors have evaluated, by DNA-probe hybridization, the presence of CMV in the cellular fractions of different body fluids from immunocompromised patients. This specific methodology appear to be rapid to perform, adaptable to different clinical samples and sensitive. Even in absence of a supporting evaluation of specific antibodies, direct detection of virus, by DNA-probe, seems to be the most efficient and rapid approach to confirm the diagnosis either of active phase or reactivating of CMV infection.

Adolescent↗
PubMedDate not supplied

Rapid diagnosis by immunofluorescence of Chlamydia trachomatis cervical infections.

In this study the MicroTrak (Syva Co.) system has been evaluated in comparison with the isolation of Chlamydia trachomatis onto McCoy cell monolayer, testing 120 endocervical samples taken from an unselected women population. The overall results show a higher incidence of positivity in women under 30 years of age; a sensitivity of the immunofluorescence of 76.3% and a specificity of 89.8%. The agreement between the two methods is significative when we test symptomatic patients.

Adult↗
PubMedDate not supplied

[Evaluation of the in vitro activity of cefotetan on bacterial strains of recent hospital isolation].

The in vitro activity of cefotetan, a new cephamycin antibiotic, was tested against 296 bacterial strains, recently clinically isolated, by measuring the minimum inhibitory concentrations. Comparisons were made with other drugs (cefoxitin, cefotaxime, piperacillin, rifampicin, clindamycin, tetracycline, chloramphenicol) widely utilized for the treatment of nosocomial infections. Cefotetan showed the highest activity against all the tested strains, with a geometrical mean of MICs (MG) of 0.32 and a MIC 50 and MIC 90 of 0.12 and 8 micrograms/ml, respectively.

Cefotaxime↗
PubMedDate not supplied

Comparative evaluation of IIF and EIA methods for serodiagnosis of toxoplasmosis.

A comparative evaluation between IIF and EIA methods for serological diagnosis of Toxoplasmosis has been carried out testing 920 serum samples. Both methods have been considered as equally valuable and accurate. The Authors prefer to utilize the IIF for screening purposes and EIA, which has been more sensitive at intermediate range of values, for the follow-up of the different immunological responses against Toxoplasma gondii.

Antibodies↗
PubMedDate not supplied

[Evaluation of a rapid computerized method (Cobas-Bact) for the determination of in vitro sensitivity to antibiotic drugs].

426 strains recent clinically isolates have been investigated with respect to their sensitivity against several chemioantibiotics. Data obtained with the Bauer and Kirby standard agar diffusion method have been compared with those carried out by using a new computerized system (Cobas-Bact, Roche), which is able to perform antibiograms in five hours. The performance of Cobas-Bact has been very significative, since the overall major concordance between the two methods was higher than 94%.

Agar↗