Adult and fetal haemoglobin J-Sardegna [alpha50(CE8)His-->Asp]: functional and molecular modelling studies.

Haemoglobin (Hb) J-Sardegna [alpha50(CE8)His-->Asp] is a haemoglobin variant characteristic of subjects from the island of Sardinia. Here we report a study of the functional properties of both fetal and adult Hb J-Sardegna. The results indicate that adult Hb J-Sardegna displays an oxygen affinity that is higher than that of adult Hb only in the presence of 2,3-diphosphoglycerate (2,3-DPG). On the contrary, at 20 degrees C, the oxygen affinity of fetal Hb J-Sardegna is identical to that of normal fetal haemoglobin, both in the presence and in the absence of 2,3-DPG. A significant difference between these two systems (i.e. a higher oxygen affinity of fetal Hb J-Sardegna) shows up very clearly only when temperature is increased to 37 degrees C. Hence in fetal Hb, the main effect of the amino acid substitution is a decrease in the overall enthalpy change of oxygenation. The results outline the role of the alpha(1)-beta(1) interface in assessing the thermodynamics of oxygen binding. The functional properties of both adult and fetal Hb J-Sardegna have been interpreted at the structural level in light of the results obtained by a computational modelling approach performed in comparison with HbA and Hb Aichi, a variant characterized by a different mutation [alpha50(CE8)His-->Arg] at the same position.

[Electrical field exposure and human health. Risk assessment and problems relative to bureaucratic procedures and to the role of instituitional organizations in control and prevention]. / Esposizione a campi elettromagnetici e salute dell'uomo. Valutazione del rischio e problematiche relative all'iter normativo e al ruolo degli organi istituzionali nel controllo e nella prevenzione.

After closely analyzing the phenomenon regarding the immense increase and diffusion of equipment which generates low- and high-frequency electromagnetic fields, the AA emphasize both the methodological and interpretive difficulties of assessing the effects produced on public health. They maintain the need to exercise caution in determining the tolerable limits of exposure, and in particular long-term ones. Finally, after analyzing the bureaucratic procedure which led to the formulation of Decree No. 381 of 1998, they express the hope that the various Regions will set themselves high-quality objectives when promulgating the necessary legislation, so as to minimize the risk factor.

Prevalence of diphtheria toxin antibodies in human sera from a cross-section of the Italian population.

A polycentric study was carried out between 1993 and 1995 in order to evaluate diphtheria immunity on a representative sample of population from different areas of Italy. To determine diphtheria antitoxin, sera from 5187 apparently healthy subjects, divided according to sex and age groups, were titrated using an ELISA indirect method. A basic protective titre of diphtheria antitoxin (> 0.01 IU ml-1) was found in 4080 (78.6%) subjects. No statistically significant differences between males and females were observed. Our findings show that the proportion of susceptibles increases with age and a high proportion of adults no longer has diphtheria antitoxin at protective levels since toxigenic C. diphtheriae circulation is presently lacking in Italy.

[Quality of housing in relation with human health. I: Building characteristics of the houses in the Marchesian region]. / Indagine sulla qualità delle abitazioni in relazione alla salute umana. Nota I: Caratteristiche edilizie delle abitazioni marchigiane.

In view of the fact that a considerable proportion of the population particularly at risk (the aged, children, the sick, etc.) spend many hours of the day indoors, the authors report the results of an investigation carried out on the building characteristics of 1833 houses sampled in four towns in the Marches region. The questionnaire of Fusillo et al. was used. The results show an excellent situation with regard both to the quality of outdoor air and acoustic pollution (only 27% of the sample complained of the vicinity of their house to zones of intense traffic). The low index of overcrowding (0.7 inhabitants per room) as well as the overall surface area of the houses (in 60% more than 100 m2), the large number of bathrooms (almost 50% of the houses with two, and another 15% with three or more), and the prevalence of detached houses are factors that show how the Marchean population pay particular attention to building criteria. However, even though from the structural standpoint the housing situation might seem a very good one, specific problems can be found, also common to other Italian regions, regarding building techniques and the materials adopted (e.g. the use of reinforced concrete, which together with the undoubted advantages it offers also has a number of disadvantages). The authors therefore stress the need for incentivating a bioecologically based building tradition, even if this is economically more costly, and give guidelines on how to conciliate the bioecological and economic aspects with regard to choice and use of materials. Finally, they express the hope that the "EC" symbol foreseen for building materials by Law No. 246 of 21 April 1993 will be adequately used in the ways laid down in appendix A to that law.

The hemoglobin polymorphism of the Sardinian wild dwarf horse and the oxygen binding properties of the four different horse hemoglobins.

A study was made of the Hb phenotype of the Sardinian dwarfhorse (Equus caballus jara), one of the last surviving wild horse species in Europe. Hb haplotypes and their frequencies were found to be similar to those described in the Arabian horse (BI = 0.551, BII = 0.389, A = 0.036, V = 0.015), which suggests possible introduction onto the island from North Africa. The oxygen binding properties of the whole hemolysates and of the four different horse Hbs, separated by ion-exchange chromatography, were considered with regard to the effect of chloride, 2,3-bisphosphoglycerate and lactate. Results indicate that no differences exist in the four components that characterize horse Hb. The molecular basis of the intrinsically low oxygen affinity and of the weak interaction of horse Hb with 2,3-bisphosphoglycerate is discussed in the light of the primary structure of the molecule.

Genome flux in tomato auto- and auxo-trophic cell clones cultured in different auxin/cytokinin equilibria. I. DNA multiplicity and methylation levels.

An analysis of the effect of changing physiological conditions on genetic stability, in terms of epigenetic changes, such as DNA, methylation patterns, and multiplicity of repetitive DNA, was carried out on tomato cell clones grown on media supplemented with different auxin/cytokinin ratios. The effect of endogenous variation in phytohormone equilibria was also indirectly analysed through a comparison of auxotrophic or habituated (autotrophic) cell clones and the differentiated leaf tissue. The data obtained showed significant variation in methylation and multiplicity levels both between clones and between treatments, clearly suggesting a contemporary influence of exogenous hormonal treatments and of the initial/endogenous physiological state of the treated tissue on both phenomena studied.

Modification of competence for in vitro response to Fusarium oxysporum in tomato cells. II. Effect of the integration of Agrobacterium tumefaciens genes for auxin and cytokinin synthesis.

We have studied the effect of a change in the endogenous hormone equilibria on the competence of tomato (Lycopersicon esculentum) cells to defend themselves against the fungal pathogen Fusarium oxysporum f. sp. lycopersici. Calluses from cvs 'Davis' and 'Red River', respectively resistant and susceptible to Fusarium and transgenic for an auxin- or cytokinin-synthesizing gene from Agrobacterium tumefaciens, were used. The integration of Agrobacterium hormone-related genes into susceptible cv 'Red River' can bring the activation of defense processes to a stable competence as assessed by the inhibition of mycelial growth in dual culture and gem-tube elongation of Fusarium conidia, the determination of callose contents, peroxidase induction and ion leakage in the presence of fusaric acid. This is particularly true when the transformation results in a change of phytohormone equilibria towards an higher cytokin in concentration. On the contrary, in resistant cv 'Davis' the inhibition of both fungal growth in dual culture and conidia germination is higher when the hormone balance is modified in favour of the auxins. No significant effect was observed for ion leakage and peroxidase induction, probably because of a constitutive overproduction of cytokinins in 'Davis' cells.

Modification of competence for in vitro response to Fusarium oxysporum in tomato cells. I. Selection from a susceptible cultivar for high and low polysaccharide content.

Plant cell walls play a major role in the outcome of host-parasite interactions. Wall fragments released from the plant, and/or the fungal pathogen, can act respectively as endogenous and exogenous elicitors of the defence response, and other wall components, such as callose, lignin, or hydroxyproline-rich glycoproteins, can inhibit pathogen penetration and/or spreading. We have previously demonstrated that calli from tomato cultivars resistant in vivo to Fusarium oxysporum f.sp. lycopersici show a high amount of polysaccharides in vitro. The aim of the present work was to assess the possible role of polysaccharide content and/or synthetic capacity in determining the competence of plant cells for active defence. For this purpose, tomato cell clones with increased and decreased polysaccharide (FL(+), FL(-)) and callose (A(+), A(-)) content have been selected by means of specific stains as visual markers and tested for the effect of these changes on the extent of response to Fusarium. The analysis of several parameters known to be indicative of active defence (cell browning after elicitor treatment, peroxidase and ß-glucanase induction and inhibition of fungal growth in dual culture) clearly shows that FL(+) and A(+) clones have acquired an increased competence for the activation of defence response. The results are thoroughly discussed in terms of an evaluation of the relative importance of constitutive and/or inducible polysaccharide synthetic capacity for plant response to pathogens, and their possible regulation by plant physiological backgrounds.

Molecular basis of low-temperature sensitivity in pig hemoglobins.

It has been generally assumed that mammals have blood with a greater temperature sensitivity than ectothermic organisms. Recent results have shown that in some species of mammals, Hb displays a value of overall oxygenation enthalpy (delta H) much less exothermic than that observed for most mammalian hemoglobins, including human adult Hb. In this respect, a very interesting case is represented by porcine blood which shows a modest effect of temperature, the temperature coefficient of its oxygen-dissociation curve being significantly lower than that of human blood. Here we report a detailed functional characterization of pig Hb, which, interpreted on the basis of the amino acid sequence of the alpha and beta chains of the molecule, sheds some light on the molecular basis of the phenomenon.

The in vitro physiological phenotype of tomato resistance to Fusarium oxysporum f. sp. lycopersici.

With the aim of dissecting host-parasite interaction processes in the system Lycopersicon aesculentum-Fusarium oxysporum f. sp. lycopersici we have isolated plant cell mutants having single-step alterations in their defense response. A previous analysis of the physiological phenotypes of mutant cell clones suggested that recognition is the crucial event for active defence, and that polysaccharide content, fungal growth inhibition, peroxidase induction in in vitro dual culture and ion leakage induced by cultural filtrates of the pathogen can be markers of resistance. In this paper we present the results of a similar analysis carried out on cell cultures from one susceptible ('Red River'), one tolerant ('UC 105') and three resistant ('Davis UC 82', 'Heinz', 'UC 90') tomato cultivars. Our data confirm that the differences in the parameters considered are correlated with resistance versus susceptibility in vivo. Therefore, these parameters can be used for early screening in selection programmes. These data, together with those obtained on isolated cell mutants, suggest that the selection in vitro for altered fungal recognition and/or polysaccharide or callose content may lead to in vivo - resistant genotypes. The data are thoroughly discussed with particular attention paid to the importance of polysaccharides in active defense initiation.

Lobster haemocyanin. Influence of acclimatization on subunit composition and functional properties.

Haemocyanin from the lobster Palinurus elephas has been shown to change in its subunit composition according to the time of year. In contrast, in Palinurus mauritanicus, a lobster living at greater depth, no seasonal changes in subunit composition have been observed. The results obtained from a set of experiments performed on some Palinurus mauritanicus acclimatized in an aquarium have clearly indicated that modifications of haemocyanin subunit composition may be involved in the adaptation of arthropods to environmental change.

Flight and heat dissipation in birds. A possible molecular mechanism.

Birds during normal sustained flight must be able to dissipate more than 8 times as much heat as during rest in order not to be overheated. The experiments reported in this note on the hemoglobin systems from two different birds indicate the existence of a molecular mechanism by which hemoglobin is used simultaneously for oxygen transport and heat dissipation.

[Daily intake of macro and trace elements in the diet. 4. Sodium, potassium, calcium, and magnesium]. / Apporto giornaliero di macro ed oligoelementi con la dieta. Nota IV--sodio, potassio, calcio, magnesio.

To complete the picture of the daily dietary intake of minerals, sodium, potassium, calcium and magnesium have now been considered. The study has been carried out in the Italian Marches Region after carefully evaluating the food consumption habits of the population. The foodstuffs comprising the 70 diets examined were collected in institutional canteens and private homes immediately prior to meals. The food was sampled ready for consumption as it had thus undergone the various preparation and cooking procedures, during which considerable changes in mineral content occur. In comparison with the various food consumption standards, the amount of sodium found appears excessively high (4.8 g/d) whereas that of magnesium is insufficient (0.24 g/d). A high sodium intake, and more recently a high Na/K ratio, have been associated with hypertension. Also a lack of magnesium and a high Ca/Mg ratio have repeatedly been associated with hypertension risk. The data to emerge from our study: a high sodium intake, an insufficiency of magnesium, and thus high Na/K and Ca/Mg ratios, would appear likely to enhance cardiovascular disease risk. Even though not all Authors agree on the existence of such correlations, a more correct diet as regards mineral intake is undoubtedly something to encourage.