Structural studies of wheat flour glutenin polymers by CD spectroscopy.

A dissolution procedure of unreduced glutenin polymers of three wheat flour varieties (WRU 6981, Alisei 1, and Alisei 2) by sonication in the presence of SDS (sodium dodecyl sulphate), after the elimination of albumins, globulins, and gliadins, was achieved, and the molecular weight distribution of glutenin polymers obtained by this method was measured by matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. A structural study by CD spectroscopy at different temperatures of WRU 6981 glutenin polymer and of 1Ax1 high-M(r) (relative molecular mass) glutenin subunit, which is the only high-M(r) subunit contained in WRU 6981 flour, was undertaken to understand if the information obtained from the single subunit were applicable to the total polymer. CD spectroscopy also has been employed to study the glutenin polymers obtained by Alisei 1 and Alisei 2 wheat flours; Alisei 1 biotype contained 1Bx7 and 1Dx2+1Dy12 high-M(r) subunits, whereas the Alisei 2 biotype contained only 1Bx7 and 1Dy12 subunits. A conformational study was undertaken by CD spectroscopy at different temperatures and in the presence of some chemical denaturant agents, such as urea and sodium dodecyl sulphate, in order to obtain information about their intrinsic stability and to verify if the 1Dx2 subunit presence determined a different structural behavior between Alisei 1 and Alisei 2 polymers. MALDI-TOF mass spectrometric experiments showed that the glutenin polymers molecular weights were in the mass range of 500000-5000000. CD spectra indicated that a single conformational state did not predominate in the temperature range studied but equilibrium between two distinct conformational states existed; moreover, all the changes induced by urea and by SDS followed a multistep transition process.

Conformational studies of wheat flour high relative molecular mass glutenin subunits by circular dichroism spectroscopy.

Conformational studies of 1Dx2, 1Bx7, and 1Dy12 high relative molecular mass glutenin subunits, extracted from Alisei 1 flour, are reported. Circular dichroism (CD) spectroscopy is employed to study their conformational polymorphism induced by urea and by urea in the presence of 1% sodium dodecyl sulfate (SDS). The CD spectra indicate that SDS promotes ordered structures. The addition of urea to the SDS-acetate solution of 1Dx2, 1Bx7, and 1Dy12 subunits eliminates the effect of SDS. Its addition to the acetate solution of proteins induces conformational transitions to form a poly-L-proline II-like structure. All the changes induced by urea follow a multistep transition process that is typical of proteins consisting of different domains.

Molecular modeling of beta-cyclodextrin complexes with nootropic drugs.

The geometry and structural features of the inclusion complexes of beta-cyclodextrin (beta-CD) with the chiral antiamnesic drugs (+/-)-1-benzyl-4-hydroxymethylpyrrolidin-2-one (WEB-1868). (+/-)-1-benzenesulfonyl-5-ethoxypyrrolidin-2-one (RU-35929), and (+/-)-1-(3-pyridinlysulfonyl)-5-ethoxypyrrolidin-2-one (RU-47010) were studied by the molecular modeling method (MacroModel interactive computer program). Docking procedures yielded the most stable complexes, which showed the aromatic ring of the guests inside the cavity and the pyrrolidinone ring out from the side of the beta-CD secondary hydroxyl groups. The binding energies were essentially due to hydrogen-bonded structures involving the C=O group of the guests. Selective interactions allowed chiral discrimination, and accordingly, separate beta-CD complexes of the R and S enantiomers of each guest compound were studied. The almost round beta-CD structure, in all the cases, assumed an elliptic shape on passing from the isolated molecule to the docked complex. The optimized structures and conformations of beta-CD and its inclusion compounds showed acceptable general agreement with information from proton nuclear magnetic resonance studies.

Molecular study on nosocomial Pseudomonas aeruginosa strains.

Nosocomial Pseudomonas aeruginosa isolates were typed by DNA fingerprinting techniques. Chromosomal DNA banding patterns, after endonuclease digestion, of six isolates from a neonatal care unit confirmed the results of O-serotyping and antimicrobial susceptibility pattern analysis. In contrast, the characterization by chromosomal DNA fingerprinting of P. aeruginosa strains isolated from patients treated in a burn unit disagreed with the two classic typing methods: in fact, isolates that varied in serotype and antibiograms showed identical restriction endonuclease profiles, whereas two indistinguishable isolates cultured from individual patients were easily and reproducibly differentiated by molecular analysis.

Multiple typing of strains of Salmonella enterica subsp. bongori ser. 48:Z35:- isolated in southern Italy.

In 1984-87, 10 isolates of Salmonella enterica subsp. bongori ser. 48:Z35:-, 9 of human source, were identified at the Southern Italy Centre of Enterobacteriaceae. This serotype had never been identified in Southern Italy before 1984. The combined use of different typing methods, with particular reference to restriction enzyme fingerprinting of plasmid and chromosomal DNA, supports the hypothesis that all Bongor serovars derive from a single strain.

Multiple typing of Salmonella typhimurium isolates: an epidemiological study.

An epidemiological study was carried out on sixty-four Salmonella typhimurium strains isolated in Palermo during the period January-July 1987 and identified at the Southern Italy Center of Enterobacteriaceae. These included 5 isolates from a small food-poisoning outbreak, which resulted antibiotic susceptible, not colicinogenic and untypable by the phage-type scheme of Anderson. Plasmid profile analysis was not a reliable method to differentiate them from non epidemic strains. The 5 epidemic isolates, belonging to biotype 25a, were assigned into NT 2 phage-type by an accessory set of phages developed in this laboratory. Such biotype/phage-type association was never detected in the remaining Salmonella typhimurium strains isolated during the first 7 months of 1987. Chromosomal DNA analysis provided additional information on the relationships among Salmonella typhimurium isolates.

Molecular relationship among Salmonella dublin isolates identified at the Center for Enterobacteriaceae of Palermo during the years 1971-85.

A molecular epidemiological study was carried out on 60 Salmonella dublin isolates identified at the Southern Italy Enterobacteriaceae Center between 1971 and 1985. These included 23 isolates from children with diarrhoea in Palermo obtained during 1984. All isolates from the outbreak of gastroenteritis in children were resistant to chloramphenicol and streptomycin and harboured two plasmids of 50 MDa and 3 MDa molecular weight, whereas the majority of the isolates identified before 1984 were susceptible to these antibiotics and carried only a 50 MDa molecular weight plasmid. Four S. dublin strains successively identified from cattle (Palermo, Foggia, Portici) and from a child (Palermo) were shown to possess similar antibiotic resistance patterns and plasmid profiles to S. dublin isolates from the outbreak of gastroenteritis in children. The 50 MDa plasmid was shown to be associated with virulence in mice, while it was not possible to assign any genetic function to the 3 MDa plasmid.

A molecular study of Salmonella strains identified from two food-poisoning outbreaks.

A molecular epidemiology study was carried out on Salmonella mbandaka and Salmonella corvallis strains identified from two food-poisoning outbreaks which occurred in August 1985 in Pistoia and in October 1985 in Sant'Ilario d'Enza (RE). All the Salmonella mbandaka strains were plasmid-free; all the epidemic Salmonella corvallis strains, in contrast to the non epidemic isolates, carried a small plasmid of approximately 2 MDa molecular weight. Restriction enzyme cleavage pattern analysis revealed that the plasmids of the epidemic strains were closely related.

A new chromogenic test for the detection of urokinase in the genus Shigella.

A simple test for detection of urokinase in Shigella is described. The test is performed by suspending a loopful of bacteria in 100 microliters of a buffered 1mM solution of benzoyl-beta-alanyl glycyl-arginyl-4-nitroanilide acetate (Chromozym U). Enzymatic activity is revealed by formation of a yellow colour after 24 h of incubation at 37 degrees C. The test is able to differentiate serotypes of Shigella dysenteriae, Shigella flexneri, Shigella boydii. The results suggest the possibility of including this chromogenic test in the biochemical assay of Shigella genus.

Qualitative organic analysis. Part 2. Identification of drugs by principal components analysis of standardized TLC data in four eluent systems and of retention indices on SE 30.

The principal components (PC) analysis of standardized Rf values in four eluent systems [ethyl acetate/methanol/30% ammonia (85:10:15), cyclohexane/toluene/diethylamine (65:25:10), ethyl acetate/chloroform (50:50), and acetone with the plate dipped in potassium hydroxide solution] and of gas chromatographic retention indices in SE 30 for 277 compounds provided a two-principal-components model that explains 82% of the total variance. The scores plot allowed identification of unknowns or restriction of the range of inquiry to very few candidates. Comparison of these candidates with those selected from another PC model derived from TLC data only allowed identification of the drug in all the examined cases.

A study on oral rehydration therapy of diarrheal disease in western Sicily.

A longitudinal study to ascertain the most common therapeutic approach to diarrheal disease by general practitioners and pediatricians was carried out in Western Sicily. Data obtained showed that of 902 home-managed cases of diarrhea observed by 58 physicians during one year, 65.3% were treated with antibiotics, 8.0% with antimotility agents and 26.7% were not treated with any pharmacological agent (rehydration or diet). Although oral rehydration therapy was widely known by physicians in Western Sicily, only a few of them were willing to use it routinely as the principal and exclusive treatment.

Salmonella and Yersinia enterocolitica in soil and dog faeces.

Dog faeces and soil samples, collected for one year from public gardens in densely inhabited areas of Palermo (Italy), were investigated for the presence of Salmonella spp. and Ye.enterocolitica, to verify the hypothesis that mechanism of spread of Ye.enterocolitica may be comparable to that of Salmonella spp. Five Salmonella and one Ye.enterocolitica were isolated from 212 dog faeces; one Salmonella and four Ye.enterocolitica from 240 soil samples. O-serotypes of Ye.enterocolitica were not belonging to human pathogenic groups. The same Salmonella spp. were present both in humans and in the environment.

Qualitative organic analysis. I. Identification of drugs by principal components analysis of standardized thin-layer chromatographic data in four eluent systems.

Principal component analysis of standardized RF values in four eluent systems [ethyl acetate-methanol-30% ammonia (85:10:15), cyclohexane-toluene-diethylamine (65:25:10), ethyl acetate-chloroform (50:50) and acetone, with the plate dipped in potassium hydroxide solution] provided a two-component model which accounts for 73% of the total variance. The "scores" plot allowed the restriction of the range of inquiry to a few candidates. This result is of great practical significance in analytical toxicology, especially when account is taken of the cost, the time, the analytical instrumentation and the simplicity of the calculations required by the method.

Isolation of Mycobacteria from drinking water in Palermo.

Mycobacteria other than tuberculosis (MOTT) were isolated from 20 of 54 samples (37%) of tap water collected in Palermo in the period April-July 1984. The 55 isolates were M. gordonae (40), M. scrofulaceum (9), MAIS organisms (3), M. fortuitum (2), M. non photochromogenic (1). M. gordonae was isolated from 16 of the 20 positive samples and in five of them in association to other MOTT. A study of MOTT spread in other levels of piping system, showed, as already reported in similar studies, that some places, like taps and tanks, are probably favourable to more or less persistent MOTT colonization.

Identification of drugs by principal components analysis of Rf data obtained by TLC in different eluent systems.

The retention factor of 54 drugs in eight eluent mixtures is reported. Principal component analysis (PCA) of these data provided a significant two-components model. These two parameters characteristic for each drug allowed an objective identification of unknown samples, provided they were included in the considered set. The analysis showed that the eluent mixtures cluster into three groups. The PCA model, using only three eluents (one for each group), was also able to restrict the range of inquiry to a few "candidates" and, in some cases, to allow unambiguous identification of the drug. These results, based on a simple and quick analytical determination (thin layer chromatography) and a reliable statistical procedure (PCA), appear to be of significant practical importance in the field of analytical toxicology.

Beta-glucuronidase activity in Enterobacteriaceae.

Beta-glucuronidase activity has been investigated in 1,221 Enterobacteriaceae strains. The test, using p-nitrophenyl-beta-D-glucuronide (pNPGlcU) agar culture, can be included easily in the routine Enterobacteriaceae biochemical assays. The test is discriminating for Enterobacteriaceae genera and species and useful for identification of some monophasic serotypes of Salmonella.

Conformational properties and in vitro antibacterial activity of some diarylsulphones.

The 2-pyridylphenylsulphone, di-2-pyridylsulphone and its p-nitro and p,p'-dinitro derivatives were synthesized and tested for antibacterial activity against a number of gram-positive and gram-negative bacteria. The electric dipole moment of these compounds were also measured (in benzene, 25 degrees) and analyzed in terms of molecular conformation in solution. The derivative compounds bearing a 5-nitro-2-pyridine fragment were found to be the most active in the series examined. Among these the nitro-2-pyridylphenylsulphone was found to have a broad-spectrum effect on gram-positive and gram-negative bacteria. Results of the conformational study in combination with microbiological data allowed discussion on the possible inferences concerning the stereochemical aspects of the interaction of diarylsulphones with bacterial receptor sites.

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.