The periplasmic hydrogenase of Desulfovibrio vulgaris (Hildenbourough) is an all Fe-containing hydrogenase. It contains two ferredoxin type [4Fe-4S] clusters, termed the F clusters, and a catalytic H cluster. Recent X-ray crystallographic studies on two Fe hydrogenases revealed that the H cluster is composed of two sub-clusters, a [4Fe-4S] cluster ([4Fe-4S](H)) and a binuclear Fe cluster ([2Fe](H)), bridged by a cysteine sulfur. The aerobically purified D. vulgaris hydrogenase is stable in air. It is inactive and requires reductive activation. Upon reduction, the enzyme becomes sensitive to O(2), indicating that the reductive activation process is irreversible. Previous EPR investigations showed that upon reoxidation (under argon) the H cluster exhibits a rhombic EPR signal that is not seen in the as-purified enzyme, suggesting a conformational change in association with the reductive activation. For the purpose of gaining more information on the electronic properties of this unique H cluster and to understand further the reductive activation process, variable-temperature and variable-field Mossbauer spectroscopy has been used to characterize the Fe-S clusters in D. vulgaris hydrogenase poised at different redox states generated during a reductive titration, and in the CO-reacted enzyme. The data were successfully decomposed into spectral components corresponding to the F and H clusters, and characteristic parameters describing the electronic and magnetic properties of the F and H clusters were obtained. Consistent with the X-ray crystallographic results, the spectra of the H cluster can be understood as originating from an exchange coupled [4Fe-4S]-[2Fe] system. In particular, detailed analysis of the data reveals that the reductive activation begins with reduction of the [4Fe-4S](H) cluster from the 2+ to the 1+ state, followed by transfer of the reducing equivalent from the [4Fe-4S](H) subcluster to the binuclear [2Fe](H) subcluster. The results also reveal that binding of exogenous CO to the H cluster affects significantly the exchange coupling between the [4Fe-4S](H) and the [2Fe](H) subclusters. Implication of such a CO binding effect is discussed.

Unconjugated bilirubin is a neurotoxic pigment that interacts with membrane lipids. In this study we used electron paramagnetic resonance and the spin labels 5-, 7-, 12-, and 16-doxyl-stearic acid (DSA) to evaluate the depth of the hydrocarbon chain at which interaction of bilirubin preferentially occurs. In addition, we used different pH values to determine the molecular species involved. Resealed right-side-out ghosts were incubated (1-60 min) with bilirubin (3.4-42.8 microM) at pH 7.0, 7.4, and 8.0. Alterations of membrane dynamic properties were maximum after 15 min of incubation with 8.6 microM bilirubin at pH 7.4 and were accompanied by a significant release of phospholipids. Interestingly, concentrations of bilirubin up to 42.8 microM and longer incubations resulted in the elution of cholesterol and further increased that of phospholipids while inducing less structural alterations. Variation of the pH values from 8.0 to 7.4 and 7.0, under conditions of maximum perturbation, led to a change from an increased to a diminished polarity sensed by 5-DSA. Conversely, a progressive enhancement in fluidity was reported by 7-DSA, followed by 12- and 16-DSA. These results indicate that bilirubin while enhancing membrane lipid order at C-5 simultaneously has disordering effects at C-7. Furthermore, recovery of membrane dynamics after 15 min of bilirubin exposure along with the release of lipids is compatible with a membrane adaptive response to the insult. In addition, our data provide evidence that uncharged diacid is the species primarily interacting with the membrane as perturbation is favored by acidosis, a condition frequently associated with hyperbilirubinemia in premature and severely ill infants.

At the last National Conference of Industrial Sociology in Portugal (in March 1999) was presented a paper on the topic of “foresight as a technology and employment policy instrument” (A.B. Moniz) where there was a reference to the need of development of this kind of tools and instruments. This need is clear when one should neutralize the negative effects of such policies, and could support the positive influences, especially with the main aims of improvement of quality of working life. Thus, is today possible to make a first balance of the application in Portugal of a type of foresight analysis exercise: the Delphi method. After some of the uses of this method in Portugal on the fisheries socio-economical system and on the relation between information society and employment, we present in this paper a first assessment of such experiments and present some recommendations for future uses of this foresight technique. We conclude that they must be applied within the context of socio-economical perspectives, and not only the technological ones, although they should include that dimension.

Taking into account the global trends towards vertical de-integration and functional integration, the WorTiS project is expected to be able to determine to what extent the Portuguese automobile industry is experiencing far-reaching changes as far as innovative (post-fordist) work systems are concerned. One of the objectives is to reach wider conclusions regarding the sector under analysis within a new multi-disciplinary approach, in connection with other research networks (namely, GERPISA and IMVP-MIT). It will recover relevant information in automobile companies located in Portugal (like, Toyota, Citröen, FIAT, Renault, Ford, VW, UMM), in order to understand how concrete practices have being developed in time, and update the scientific knowledge with the development of new case studies (Mitsubishi, AutoEuropa, Opel-GM, and other sub-contracting firms). is intended to present a new fieldwork methodology in order to analyse the variety, and contradictory character, of changes in work practices. The analysis would focus on the cases of automotive firms that operated, and are still operating, in Portugal. The effectiveness of such a tool will last far beyond the project itself.

At the last National Conference of Industrial Sociology in Portugal (in March 1999) was presented a paper on the topic of “foresight as a technology and employment policy instrument” (A.B. Moniz) where there was a reference to the need of development of this kind of tools and instruments. This need is clear when one should neutralize the negative effects of such policies, and could support the positive influences, especially with the main aims of improvement of quality of working life. Thus, is today possible to make a first balance of the application in Portugal of a type of foresight analysis exercise: the Delphi method. After some of the uses of this method in Portugal on the fisheries socio-economical system and on the relation between information society and employment, we present in this paper a first assessment of such experiments and present some recommendations for future uses of this foresight technique. We conclude that they must be applied within the context of socio-economical perspectives, and not only the technological ones, although they should include that dimension.

Taking into account the global trends towards vertical de-integration and functional integration, the WorTiS project is expected to be able to determine to what extent the Portuguese automobile industry is experiencing far-reaching changes as far as innovative (post-fordist) work systems are concerned. One of the objectives is to reach wider conclusions regarding the sector under analysis within a new multi-disciplinary approach, in connection with other research networks (namely, GERPISA and IMVP-MIT). It will recover relevant information in automobile companies located in Portugal (like, Toyota, Citröen, FIAT, Renault, Ford, VW, UMM), in order to understand how concrete practices have being developed in time, and update the scientific knowledge with the development of new case studies (Mitsubishi, AutoEuropa, Opel-GM, and other sub-contracting firms). is intended to present a new fieldwork methodology in order to analyse the variety, and contradictory character, of changes in work practices. The analysis would focus on the cases of automotive firms that operated, and are still operating, in Portugal. The effectiveness of such a tool will last far beyond the project itself.

The structural changes in the heme macrocycle and substituents caused by binding of Ca2+ to the diheme cytochrome c peroxidase from Paracoccus pantotrophus were clarified by resonance Raman spectroscopy of the inactive fully oxidized form of the enzyme. The changes in the macrocycle vibrational modes are consistent with a Ca2+-dependent increase in the out-of-plane distortion of the low-potential heme, the proposed peroxidatic heme. Most of the increase in out-of-plane distortion occurs when the high-affinity site I is occupied, but a small further increase in distortion occurs when site II is also occupied by Ca2+ or Mg2+. This increase in the heme distortion explains the red shift in the Soret absorption band that occurs upon Ca2+ binding. Changes also occur in the low-frequency substituent modes of the heme, indicating that a structural change in the covalently attached fingerprint pentapeptide of the LP heme occurs upon Ca2+ binding to site I. These structural changes may lead to loss of the sixth ligand at the peroxidatic heme in the semireduced form of the enzyme and activation.

The results presented in this article are related to the field of investigation defined inside the European TSER project on "Information Society, Work and Generation of New Forms of Social Exclusion " (SOWING). The thematic center of the project is connected with the question of the relations that exist between the introduction of information technologies (IT) and the changes in the waged labour as well as in the organisation of work systems. The introduction of these technologies transformed specially the activities on services as well as certain branches, where great changes of the organization of work for the next future assume, which are discussed within the margin of the debate on future forms of work. The tendencies within the occupational structures indicate an individualisation of the insecurities and an opening of the occupational carreers. For these reasons, the development of the occupational carreers is more and more bound to the biographical planning. The institutionalised occupational model is changing very strongly, which in the long term will take to social and cultural changes, not only in the professional life, but also in the private life.

The most significative text of the European Commission on the construction of a strategy for an Information Society is, undoubtly the document on “Job Opportunities in the Information Society”. The major dimension of the change process was not anymore the technological evolution one. Information society should integrate the social-economical dimensions with industries that use information and communication products and services, beside those of so-called “Information Society industries”. Is not only this sector that is growing in terms of employment, but also the other sectors can be also important ICT users. Employment in the information society leads the employment growth in EU. In this study are analysed the different national programs and strategies, and with particular relevance the Portuguese case.

The relation between work organisation and technological practices in auto industry is analysed in this article. The concept of “technological practice” in this sector is used to describe the specific ways of embedding information and communication technology applications into the organizational forms and cultural patterns. This concept was developed with the Sowing project (TSER, DG XII) and that approach included either the shop floor co-operation up to the regionally based networks of companies and supporting institutions. The authors studied different sectors in the automotive firms of different European countries (Germany, Belgium and Portugal): shopfloor and production lines, design and management and the local inter-relationships. It was underlined some evidencies of the different alternatives in terms of technological practices for the same sector. Much of the litterature try to disseminate an idea of a single (and optimum) organisational model for the same type of product. And here, even with the same type of technology, and of product (medium-high range), one can find different models, different cultures, different ways of organising the industrial structure (firms, regional institutions, R&D centres) in the same sector (auto industry).

The results presented in this article are related to the field of investigation defined inside the European TSER project on "Information Society, Work and Generation of New Forms of Social Exclusion " (SOWING). The thematic center of the project is connected with the question of the relations that exist between the introduction of information technologies (IT) and the changes in the waged labour as well as in the organisation of work systems. The introduction of these technologies transformed specially the activities on services as well as certain branches, where great changes of the organization of work for the next future assume, which are discussed within the margin of the debate on future forms of work. The tendencies within the occupational structures indicate an individualisation of the insecurities and an opening of the occupational carreers. For these reasons, the development of the occupational carreers is more and more bound to the biographical planning. The institutionalised occupational model is changing very strongly, which in the long term will take to social and cultural changes, not only in the professional life, but also in the private life.

The results presented in this article are related to the field of investigation defined inside the European TSER project on "Information Society, Work and Generation of New Forms of Social Exclusion " (SOWING). The thematic center of the project is connected with the question of the relations that exist between the introduction of information technologies (IT) and the changes in the waged labour as well as in the organisation of work systems. The introduction of these technologies transformed specially the activities on services as well as certain branches, where great changes of the organization of work for the next future assume, which are discussed within the margin of the debate on future forms of work. The tendencies within the occupational structures indicate an individualisation of the insecurities and an opening of the occupational carreers. For these reasons, the development of the occupational carreers is more and more bound to the biographical planning. The institutionalised occupational model is changing very strongly, which in the long term will take to social and cultural changes, not only in the professional life, but also in the private life.

The most significative text of the European Commission on the construction of a strategy for an Information Society is, undoubtly the document on “Job Opportunities in the Information Society”. The major dimension of the change process was not anymore the technological evolution one. Information society should integrate the social-economical dimensions with industries that use information and communication products and services, beside those of so-called “Information Society industries”. Is not only this sector that is growing in terms of employment, but also the other sectors can be also important ICT users. Employment in the information society leads the employment growth in EU. In this study are analysed the different national programs and strategies, and with particular relevance the Portuguese case.

The relation between work organisation and technological practices in auto industry is analysed in this article. The concept of “technological practice” in this sector is used to describe the specific ways of embedding information and communication technology applications into the organizational forms and cultural patterns. This concept was developed with the Sowing project (TSER, DG XII) and that approach included either the shop floor co-operation up to the regionally based networks of companies and supporting institutions. The authors studied different sectors in the automotive firms of different European countries (Germany, Belgium and Portugal): shopfloor and production lines, design and management and the local inter-relationships. It was underlined some evidencies of the different alternatives in terms of technological practices for the same sector. Much of the litterature try to disseminate an idea of a single (and optimum) organisational model for the same type of product. And here, even with the same type of technology, and of product (medium-high range), one can find different models, different cultures, different ways of organising the industrial structure (firms, regional institutions, R&D centres) in the same sector (auto industry).

The intermolecular electron transfer kinetics between nitrite reductase (NiR, cytochrome cd1) isolated from Pseudomonas nautica and three cytochromes c isolated from the same strain, as well as the intramolecular electron transfer between NiR heme c and NiR heme d1, were investigated by cyclic voltammetry. All cytochromes (cytochrome c552, cytochrome c553 and cytochrome C553(548)) exhibited well-behaved electrochemistry. The individual diffusion coefficients and mid-point redox potentials were determined. Under the experimental conditions, only cytochrome c552 established a rapid electron transfer with NiR. At acidic pH, the intermolecular electron transfer (cytochrome c(552red)-->NiR heme cox) is a second-order reaction with a rate constant (k2) of 4.1+/-0.1x10(5) M(-1) s(-1) (pH=6.3 and 100 mM NaCl). Under these conditions, the intermolecular reaction represents the rate-limiting step. A minimum estimate of 33 s(-1) could be determined for the first-order rate constant (k1) of the intramolecular electron transfer reaction NiR heme c(red)-->NiR heme d1ox. The pH dependence of k2 values was investigated at pH values ranging from 5.8 to 8.0. When the pH is progressively shifted towards basic values, the rate constant of the intramolecular electron transfer reaction NiR heme c(red)-->NiR heme d1ox decreases gradually to a point where it becomes rate limiting. At pH 8.0 we determined a value of 1.4+/-0.7 s(-1), corresponding to a k2 value of 2.2+/-1.1x10(4) M(-1) s(-1) for the intermolecular step. The physiological relevance of these results is discussed with a particular emphasis on the proposed mechanism of "dead-end product" formation.

Mitochondria have been implicated in the cytotoxicity of amyloid beta-peptide (A beta), which accumulates as senile plaques in the brain of Alzheimer's disease patients. Tauroursodeoxycholate (TUDC) modulates cell death, in part, by preventing mitochondrial membrane perturbation. Using electron paramagnetic resonance spectroscopy analysis of isolated mitochondria, we tested the hypothesis that A beta acts locally in mitochondrial membranes to induce oxidative injury, leading to increased membrane permeability and subsequent release of caspase-activating factors. Further, we intended to determine the role of TUDC at preventing A beta-induced mitochondrial membrane dysfunction. The results demonstrate oxidative injury of mitochondrial membranes during exposure to A beta and reveal profound structural changes, including modified membrane lipid polarity and disrupted protein mobility. Cytochrome c is released from the intermembrane space of mitochondria as a consequence of increased membrane permeability. TUDC, but not cyclosporine A, almost completely abrogated A beta-induced perturbation of mitochondrial membrane structure. We conclude that A beta directly induces cytochrome c release from mitochondria through a mechanism that is accompanied by profound effects on mitochondrial membrane redox status, lipid polarity, and protein order. TUDC can directly suppress A beta-induced disruption of the mitochondrial membrane structure, suggesting a neuroprotective role for this bile salt.

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