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Biomedical subjects

E Longo

Publications and source records attributed to E Longo.

28 records · Page 2Linked to original sources
PubMed1988

Induction of petite yeast mutants by membrane-active agents.

Ethanol proved to be a strong mutagenic agent of Saccharomyces mitochondrial DNA. Other active membrane solvents, such as tert-butanol, isopropanol, and sodium dodecyl sulfate, also turned out to be powerful petite mutation [rho-] inducers. Mutants defective in ergosterol synthesis (erg mutants) showed an extremely high frequency of spontaneous petite cells, suggesting that mitochondrial membrane alterations that were caused either by changes in its composition, as in the erg mutants, or by the effects of organic solvents resulted in an increase in the proportion of petite mutants. Wine yeast strains were generally more tolerant to the mutagenic effects of alcohols on mitochondrial DNA and more sensitive to the effect of sodium dodecyl sulfate than laboratory strains. However, resistance to petite mutation formation in laboratory strains was increased by mitochondrial transfer from alcohol-tolerant wine yeasts. Hence, the stability of the [rho+] mitochondrial DNA in either the presence or absence of solvents depends in part on the nature of the mitochondrial DNA itself. The low frequency of petite mutants found in wine yeast-laboratory yeast hybrids and the fact that the high frequency of petite mutants of a particular wine spore segregated meiotically indicated that many nuclear genes also play an important role in the mitochondrial genome in both the presence and absence of membrane solvents.

Cell Membrane↗
PubMed1987

[Taxonomic study of epiphyte lactic bacteria in grapes in Galicia].

A taxonomic analysis of the malolactic microflora present in nine grape samples from different zones of Galicia, was carried out. Nineteen strains were isolated and identified as Lactobacillus plantarum (42%), L. brevis (10.6%), L. casei (5.25%), L. hilgardii (5.25%), Streptococcus cremoris (5.25%), Leuconostoc lactis (5.25%), L. oenos (10.6%), and Pediococcus acidilactici (15.8%).

Fruit↗
PubMed1986

The catalytic mechanism of serine proteases. III. An Indo-ISCRF study of the methylacetate docking in alpha-chymotrypsin.

Mechanistic steps of the catalytic hydrolysis of methylacetate by alpha-chymotrypsin have been studied with the inhomogeneous selfconsistent reaction field theory of protein core effects. Protein-substrate interactions were optimized at each step of the reaction path by using the REFINE program. The state of charge of the acid and basic side chains together with the amino terminal group have been used to mimic pH effects. The experimental facts concerning the catalytic activity are fairly well reproduced in our simulations. In particular, the trends in activation barrier as a function of pH are good, although the actual energetic barriers are much too large.

Acetates↗
PubMed1985

The catalytic mechanism of serine proteases II: The effect of the protein environment in the alpha-chymotrypsin proton relay system.

The proton relay system of alpha-chymotrypsin is analyzed by the INDOISCRF method. The effects of the protein electric and polarization fields are explicitly introduced in the calculations. It is shown that the multicharged structure Ser-His+Asp- is the most sensitive, from an energetic view-point, towards the protein surrounding effects. Variations in the permanent and polarization fields are discussed, as well as the influence of the substrate and one water molecule localized in the active site of the enzyme. The catalytic role of such changes is conjectured.

Binding Sites↗
PubMed1984

The catalytic mechanism of serine proteases: single proton versus double proton transfer.

The two possible mechanisms of proton transfer on the catalytic process of serine proteases (single or double proton transfer) have been analysed. Intermediate neglect of differential overlap calculations have been performed in the absence and in the presence of the substrate molecule and one water molecule localized in the active site. It is shown that, in the absence of the substrate and water, double proton transfer seems to be the most feasible mechanism. However, when these molecules are introduced in the calculation, the role played by them is to facilitate the formation of the zwitterionic structure (single proton transfer) and to destabilize the intermediate structure which leads to double proton transfer. All calculations were made in vacuo.

Binding Sites↗
PubMed1981

Postpericardiotomy syndrome in adults: incidence, autoimmunity and virology.

While continuing a study of immunologic and virologic aspects of the postpericardiotomy syndrome (PPS) in infants and children, we undertook a companion study in adults. Whereas the incidence in 119 children was 27.8%, as is usual for our hospital, the incidence in 142 adults was 17.6%. Most of the operations (95 of 142) were performed on patients who were 50-69 years old. Incidence decreased as age increased: 28.5% for ages less than 40 years, 19.7% for ages 40--59 years, 14.2% for ages 60--69 years, and 10% for ages 70 years and older. Heart-reactive antibody in high titer was found in all patients with PPS; a rise in antiviral antibody to one or more of a battery of eight common viruses (adenovirus, cytomegalovirus, and coxsackie-virus B 1 to 6) was identified in 68% of these with PPS but in only 5% of those without clinical manifestations. We conclude that in adults, as in children, PPS may be an autoimmune phenomenon triggered by viral illness.

Adult↗
PubMed1979

[Chronic depressions (author's transl)].

The definition of chronic depression necessarily calls for a review of the concept of recovery which in psychopathology is not clearly and univocally defined. The percentage of chronic evolution among depressive patients either as a persistence of depressive symptoms or as an impairment of social and professional role, ranges from 12 to 15%. Chronic depression raises psychopathologic and nosographic problems as well as clinical ones. In fact chronic depressives are often not correctly diagnosed, inadequately treated and destined to be affected by an over increasing inability. The chronic evolution of depression may result as a concurrence of several factors: a neurotic personality, an inadequate antidepressant maintenance treatment, an inappropriated use of minor tranquillizers as the only treatment. The occurrence of physical impairement, the continuous nature of depression and the resistance of antidepressant treatment may be also considered. Moreover the psychodynamic mechanisms aroused by the depressive experience and the secondary advantages of the illness may plan an effective role maintaining depressive symptomatology.

Bipolar Disorder↗
PubMedDate not supplied

UV radiation: aggressive agent to the hair--AFM, a new methodology of evaluation.

A new method for morphological hair analysis at high resolution and under ambient conditions is presented in this paper. The AFM has been used in these experiments to analyze morphological changes in hair roughness and thickness after UV radiation. Through the powerful analytical AFM tools, changes in hair morphology can be proven. A new quantitative methodology to evaluate hair structure is presented in this paper.

Hair↗