Rhodococcus aetherivorans BCP1 as cell factory for the production of intracellular tellurium nanorods under aerobic conditions

Background: Tellurite (TeO32-) is recognized as a toxic oxyanion to living organisms. However, mainly anaerobic or facultative-anaerobic microorganisms are able to tolerate and convert TeO32- into the less toxic and available form of elemental Tellurium (Te0), producing Te-deposits or Te-nanostructures. The use of TeO32--reducing bacteria can lead to the decontamination of polluted environments and the development of "green-synthesis" methods for the production of nanomaterials. In this study, the tolerance and the consumption of TeO32- have been investigated, along with the production and characterization of Te-nanorods by Rhodococcus aetherivorans BCP1 grown under aerobic conditions. Results: Aerobically grown BCP1 cells showed high tolerance towards TeO32- with a minimal inhibitory concentration (MIC) of 2800μg/mL (11.2mM). TeO32- consumption has been evaluated exposing the BCP1 strain to either 100 or 500μg/mL of K2TeO3 (unconditioned growth) or after re-inoculation in fresh medium with new addition of K2TeO3 (conditioned growth). A complete consumption of TeO32- at 100μg/mL was observed under both growth conditions, although conditioned cells showed higher consumption rate. Unconditioned and conditioned BCP1 cells partially consumed TeO32- at 500μg/mL. However, a greater TeO32- consumption was observed with conditioned cells. The production of intracellular, not aggregated and rod-shaped Te-nanostructures (TeNRs) was observed as a consequence of TeO32- reduction. Extracted TeNRs appear to be embedded in an organic surrounding material, as suggested by the chemical-physical characterization. Moreover, we observed longer TeNRs depending on either the concentration of precursor (100 or 500μg/mL of K2TeO3) or the growth conditions (unconditioned or conditioned grown cells). Conclusions:Rhodococcus aetherivorans BCP1 is able to tolerate high concentrations of TeO32- during its growth under aerobic conditions. Moreover, compared to unconditioned BCP1 cells, TeO32- conditioned cells showed a higher oxyanion consumption rate (for 100μg/mL of K2TeO3) or to consume greater amount of TeO32- (for 500μg/mL of K2TeO3). TeO32- consumption by BCP1 cells led to the production of intracellular and not aggregated TeNRs embedded in an organic surrounding material. The high resistance of BCP1 to TeO32- along with its ability to produce Te-nanostructures supports the application of this microorganism as a possible eco-friendly nanofactory

Growth of Rhodococcus sp. strain BCP1 on gaseous n-alkanes: New metabolic insights and transcriptional analysis of two soluble di-iron monooxygenase genes

Rhodococcus sp. strain BCP1 was initially isolated for its ability to grow on gaseous n-alkanes, which act as inducers for the co-metabolic degradation of low-chlorinated compounds. Here, both molecular and metabolic features of BCP1 cells grown on gaseous and short-chain n-alkanes (up to n-heptane) were examined in detail. We show that propane metabolism generated terminal and sub-terminal oxidation products such as 1- and 2-propanol, whereas 1-butanol was the only terminal oxidation product detected from n-butane metabolism. Two gene clusters, prmABCD and smoABCD-coding for Soluble Di-Iron Monooxgenases (SDIMOs) involved in gaseous n-alkanes oxidation-were detected in the BCP1 genome. By means of Reverse Transcriptase-quantitative PCR (RT-qPCR) analysis, a set of substrates inducing the expression of the sdimo genes in BCP1 were assessed as well as their transcriptional repression in the presence of sugars, organic acids, or during the cell growth on rich medium (Luria-Bertani broth). The transcriptional start sites of both the sdimo gene clusters were identified by means of primer extension experiments. Finally, proteomic studies revealed changes in the protein pattern induced by growth on gaseous- (n-butane) and/or liquid (n-hexane) short-chain n-alkanes as compared to growth on succinate. Among the differently expressed protein spots, two chaperonins and an isocytrate lyase were identified along with oxidoreductases involved in oxidation reactions downstream of the initial monooxygenase reaction step

Assembly, growth and conductive properties of tellurium nanorods produced by Rhodococcus aetherivorans BCP1

Tellurite (TeO32-) is a hazardous and toxic oxyanion for living organisms. However, several microorganisms can bioconvert TeO32- into the less toxic form of elemental tellurium (Te0). Here, Rhodococcus aetherivorans BCP1 resting (non-growing) cells showed the proficiency to produce tellurium-based nanoparticles (NPs) and nanorods (NRs) through the bioconversion of TeO32-, depending on the oxyanion initial concentration and time of cellular incubation. Te-nanostructures initially appeared in the cytoplasm of BCP1 cells as spherical NPs, which, as the exposure time increased, were converted into NRs. This observation suggested the existence of an intracellular mechanism of TeNRs assembly and growth that resembled the chemical surfactant-assisted process for NRs synthesis. The TeNRs produced by the BCP1 strain showed an average length (>700 nm) almost doubled compared to those observed in other studies. Further, the biogenic TeNRs displayed a regular single-crystalline structure typically obtained for those chemically synthesized. The chemical-physical characterization of the biogenic TeNRs reflected their thermodynamic stability that is likely derived from amphiphilic biomolecules present in the organic layer surrounding the NRs. Finally, the biogenic TeNRs extract showed good electrical conductivity. Thus, these findings support the suitability of this strain as eco-friendly biocatalyst to produce high quality tellurium-based nanomaterials exploitable for technological purposes

The role of right and left parietal lobes in the conceptual processing of numbers

Neuropsychological and functional imaging studies have associated the conceptual processing of numbers with bilateral parietal regions (including intraparietal sulcus). However, the processes driving these effects remain unclear because both left and right posterior parietal regions are activated by many other conceptual, perceptual, attention, and response-selection processes. To dissociate parietal activation that is number-selective from parietal activation related to other stimulus or response-selection processes, we used fMRI to compare numbers and object names during exactly the same conceptual and perceptual tasks while factoring out activations correlating with response times. We found that right parietal activation was higher for conceptual decisions on numbers relative to the same tasks on object names, even when response time effects were fully factored out. In contrast, left parietal activation for numbers was equally involved in conceptual processing of object names. We suggest that left parietal activation for numbers reflects a range of processes, including the retrieval of learnt facts that are also involved in conceptual decisions on object names. In contrast, number selectivity in right parietal cortex reflects processes that are more involved in conceptual decisions on numbers than object names. Our results generate a new set of hypotheses that have implications for the design of future behavioral and functional imaging studies of patients with left and right parietal damage

ANTROPOLOGIE DEI DIRITTI UMANI. PERCORSI AFRICANI.

The Human Rights topic is increasing its relevance in the field of legal studies and in the agenda of inter/transnational actors. The Sociology of Law is deeply engaged in this dialogue, but some of its contributions seem to share a common lack of concern about the dimensions of cultural legitimacy and politics of imagination. Refusing the \u201csimplistic\u201d vision of \uablegal transplants\ubb, the approach in term of regionalization and the genealogical theories (i.e. the so called generations of human rights), the thesis aims to outline a multidisciplinary frame, trying to merge the anthropological and the socio-legal knowledge to shed light on the \uabanthropologies of human rights\ubb. The use of the plural suggests several orders of realities: firstly, it reflects the high fragmentation which characterizes the epistemological and methodological debate of contemporary anthropology, as a disciplinary field. An \u201cinternal\u201d multiplication of points of view which becomes even more striking in its interactions whit the HR subject and its own kind of internal dissemination. Secondly (and consequently), it enlightens that the \u201cpluralisation\u201d of human rights discourse could be better understood as a proliferation of world-visions and axiologies. In this second meaning, the summoned \uabanthropologies\ubb have to be intended in term of theories on human beings, on social reality and social order, shaped by cultural assumptions, taken-for-granted and (shared) symbolical repertoires. Deeply merged within every manifestation of the \uabhumanitarian transnational narration\ubb, these world-versions need to be studied as sources of influence and inspiration for legal claims, texts and declarations that build the corpus of international humanitarian law. Lastly, this plurality which stems from the relationship between the macro-narrative of the International Bill of Human Rights and its situated appropriations points out the potentiality of a cultural analysis of the social life of (human) rights in avoiding the dichotomist models (universalism versus relativism, global versus local and so on) in favor of a representation in term of narrative encounters between different conceptions of human dignity, human beings, normative orders and social realities. To grasp this mutual and multilayered overlapping, the first part of the thesis builds an analytical framework destined to be applied, in the second part, to the specific context of the \uabAfrican system of human rights\ubb. This choice was dictated by the peculiarities which seem to distinguish it from others regional systems: amongst these features, the African Charter on Human and Peoples\u2019 Rights deserves a special place, considered its aspects of relevant innovation and creativity as well its signs of criticism and its lack of real efficacy. In the first chapter we start from the general liaison between Law and Culture, looking for a \uabrelational paradigm\ubb which rejects determinist or reductionist presentations of this organic link. Adopting a pluralist point of view (centered on the idea of \uabnormative pluralism\ubb preferred to the classical one in term of \uablegal pluralism\ubb), we borrow some insights from early anthropological researches on \uabprimitive law\ubb and on the co-existence of plural normative orders in colonial settings. The second chapter deals with the concept of \uablegal culture\ubb, trying to discuss a cardinal notion of sociology of law that often pretend to exhaustively grasp the complexity of law/culture nexus. We explore the richness and the pitfalls of influent theorizations about this topic, sorting out three dimensions which seem to require a deeper engagement: the power, the (construction of the) collective identities and the pluralism. In strict dialogue with the studies on \uablegal consciousness\ubb and \uablegal socialization\ubb, we move towards a textual description of culture. The third chapter sketches a theory of culture in term of cognitive and normative interface between men and the meaningful world they try to create (and to live in). Borrowing from Clifford Geertz the fundamental ideas about the \uabsocial traffic of meanings\ubb, the textual dimension of cultures and the law as a way of world-making \u2013 or better, of imaging the reality \u2013, we keep developing our model in a more comprehensive perspective which dismisses the \u201cliterary\u201d constraints entrenched in the idea of \uabtext\ubb. The forth chapter deals with some assumptions of the so-called \uabnarrative paradigm\ubb, trying to \u201cdissolve\u201d the persisting rigidities of the textual frame into a larger and (more) universal human ability: the narrative competence. We examine the coalescence between narrative attitude and normative attitude, stressing the similarities and the constitutive power of both of them. Starting from narration as a meta-model for the social construction of reality, we move towards the specificities of \uablegal narration\ubb as expression of the legal construction of social reality. This narrative standpoint can be synthesized as follow: the human skill to produce, to understand and to manipulate tales (and other sources of narrative production) is the key that ensures the transmission and the socializations of cultural meanings, representations and symbols. Trough the narrativization of culture it becomes easier to conceive the narrativization of legal cultures as shared, contested, polyphonic repertories of legal and social ideas. In the fifth chapter we start applying our theoretical framework to the human rights topic. We begin with a preliminary set of issues regrouped under the label of \uabspatial problematic\ubb. It underlines the paradox of the Universalist project, with its claims of cultural independence and planetary applicability on the one hand, and the need of cultural resonance and local relevance on the other. We explore critical contributions about the \uabglobalization talk\ubb, which stress some traps of this overriding way of representing social and socio-legal phenomena in the contemporary world. Aiming to reject monodimensional explanations, we merge the \uabrhetoric of flaws\ubb with the sensibility for \uabfriction events\ubb generated by and trough the encounters between transnational narratives and specific local (and cultural) settings. The concept of \uabvernacularization\ubb helps us to conceive these interactions/intersections between global flows and punctual frictions. The sixth chapter introduces the main elements of the African context, starting from a sketched portrait of what we define its \uabradical normative pluralism\ubb. In order to cope with the complex reality of the African human rights system, we outline a historical (and political) description of the events that preceded the creation of the Organization for the African Unity, the institutional body which had the main responsibility in the consolidation of the system itself. We also examine various \u201clegal\u201d precedents (the so-called Lagos Law, the Universal Declaration of the Rights of Peoples and so on) which influenced the elaboration of the African Charter with their moral and political authority. Whit the seventh chapter we finally land the heart of our topic: the narrative analysis of the African Charter of Human and Peoples\u2019 Rights. After a quick identification of the focal features of the document, we approach the meaningful core of the Charter: the organic/holistic relationship between individual human rights and collective dimension of peoples\u2019 (human) rights. We split our investigation in two different but related paths: the individual/people pole and the rights/duties pole, assuming they are two dissimilar strategies to arrange this underlying \u201ccohabitation\u201d. We also draw to several pronunciations of the African Commission of human and peoples\u2019 rights exploring the potential meanings of people and peoples\u2019 rights to clarify the official/institutional position on the subject. Anthropological and sociological studies on the ongoing modifications of collective frames of reference (the family, the ethnic group and other strategies of kinship allegiance) in contemporary Africa are employed to complete our inquiry. In the eighth chapter we (temporary) leave the African Charter in favor of other documents and protocols produced by the African system, strictly related to the \uabculture variable\ubb: the Pan-African Cultural Manifesto, the Cultural Charter for Africa and the Charter for African Cultural Renaissance. After that, we approach three other texts more engaged on the promotion and protection of human rights for specific categories of people: the African Charter on the rights and welfare of the child, the Protocol to the African Charter on human and peoples\u2019 rights on the rights of women in Africa and the African Youth Charter. Our aim is to show how cultural assumptions about the subjects concerned shape or influence the normative prescriptions designed to protect them. The ninth chapter, finally, outlines a general evaluation of our analytical model trough the exploration of its weakness and its points of strength. It shows the hermeneutical advantages provided by the \uabgius-narrative\ubb key, which enabled us to trace and emphasize the links between myths and foundational narratives of social groups and theirs normative constructions. It also stresses the need for a cultural study of social life of human rights, to (try to) grasp the many faces that the struggle for human rights is showing in its continuous spread around the world

The different story of π bonds

We revisit “classical” issues in multiply bonded systems between main groups elements, namely the structural distortions that may occur at the multiple bonds and that lead, e.g., to trans-bent and bond-length alternated structures. The focus is on the role that orbital hybridization and electron correlation play in this context, here analyzed with the help of simple models for σ-and π-bonds, numerically exact solutions of Hubbard Hamiltonians and first principles (density functional theory) investigations of an extended set of systems

La concepción de alma psykhé como problema epistemológico fundamental de la psicología contemporánea

El trabajo expone en primer término las dificultades que se encuentran al realizar un análisis reduccionista de la complejidad del mundo del conocimiento científico; se afirma que para una consideración integral del conocimiento científico y tecnológico contemporáneo es necesario un análisis que se dirija a su multidimensionalidad. En segundo lugar, se abordan los problemas epistemológicos de la Psicología en lo que hace a la fragmentación del campo disciplinar, el problema de la cientificidad de la disciplina y los problemas vinculados a las relaciones entre la psicología y la filosofía. Finalmente, y en función de lo anterior se formulan algunos interrogantes a manera de resultados parciales de la indagación, con respecto a la posibilidad de pensar a la Psicología contemporánea de manera global bajo la idea fundamental de un retorno a lo que fueron sus comienzos, es decir, a una reflexión filosófica en torno al alma-psykhé, en el marco de una crítica a su devenir adaptacionista y su presente tecnocrático.This paper analyzes the difficulties encountered in the attempt to carry out a reductionist analysis of the complexity of the scientific knowledge world; It is stated that for an integral consideration of contemporary scientific and technological knowledge, it is necessary an analysis that addresses its multidimensionality. Secondly, the epistemological problems of psychology are dealt in relationship with the fragmentation of the disciplinary field, with the problem of the scientificity of the discipline and with the problems related to the links between psychology and philosophy. Finally, it highlights the need to return to a meditation on the soul-psykhé if what it is meant is to contribute to a critique aimed at the constitution of psychology as a regulating technoscience of behaviors.Mesa de trabajos libres: Epistemología y Metodología de la PsicologíaFacultad de Psicologí

La concepción de alma psykhé como problema epistemológico fundamental de la psicología contemporánea

El trabajo expone en primer término las dificultades que se encuentran al realizar un análisis reduccionista de la complejidad del mundo del conocimiento científico; se afirma que para una consideración integral del conocimiento científico y tecnológico contemporáneo es necesario un análisis que se dirija a su multidimensionalidad. En segundo lugar, se abordan los problemas epistemológicos de la Psicología en lo que hace a la fragmentación del campo disciplinar, el problema de la cientificidad de la disciplina y los problemas vinculados a las relaciones entre la psicología y la filosofía. Finalmente, y en función de lo anterior se formulan algunos interrogantes a manera de resultados parciales de la indagación, con respecto a la posibilidad de pensar a la Psicología contemporánea de manera global bajo la idea fundamental de un retorno a lo que fueron sus comienzos, es decir, a una reflexión filosófica en torno al alma-psykhé, en el marco de una crítica a su devenir adaptacionista y su presente tecnocrático.This paper analyzes the difficulties encountered in the attempt to carry out a reductionist analysis of the complexity of the scientific knowledge world; It is stated that for an integral consideration of contemporary scientific and technological knowledge, it is necessary an analysis that addresses its multidimensionality. Secondly, the epistemological problems of psychology are dealt in relationship with the fragmentation of the disciplinary field, with the problem of the scientificity of the discipline and with the problems related to the links between psychology and philosophy. Finally, it highlights the need to return to a meditation on the soul-psykhé if what it is meant is to contribute to a critique aimed at the constitution of psychology as a regulating technoscience of behaviors.Mesa de trabajos libres: Epistemología y Metodología de la PsicologíaFacultad de Psicologí

La concepción de alma psykhé como problema epistemológico fundamental de la psicología contemporánea

El trabajo expone en primer término las dificultades que se encuentran al realizar un análisis reduccionista de la complejidad del mundo del conocimiento científico; se afirma que para una consideración integral del conocimiento científico y tecnológico contemporáneo es necesario un análisis que se dirija a su multidimensionalidad. En segundo lugar, se abordan los problemas epistemológicos de la Psicología en lo que hace a la fragmentación del campo disciplinar, el problema de la cientificidad de la disciplina y los problemas vinculados a las relaciones entre la psicología y la filosofía. Finalmente, y en función de lo anterior se formulan algunos interrogantes a manera de resultados parciales de la indagación, con respecto a la posibilidad de pensar a la Psicología contemporánea de manera global bajo la idea fundamental de un retorno a lo que fueron sus comienzos, es decir, a una reflexión filosófica en torno al alma-psykhé, en el marco de una crítica a su devenir adaptacionista y su presente tecnocrático.This paper analyzes the difficulties encountered in the attempt to carry out a reductionist analysis of the complexity of the scientific knowledge world; It is stated that for an integral consideration of contemporary scientific and technological knowledge, it is necessary an analysis that addresses its multidimensionality. Secondly, the epistemological problems of psychology are dealt in relationship with the fragmentation of the disciplinary field, with the problem of the scientificity of the discipline and with the problems related to the links between psychology and philosophy. Finally, it highlights the need to return to a meditation on the soul-psykhé if what it is meant is to contribute to a critique aimed at the constitution of psychology as a regulating technoscience of behaviors.Mesa de trabajos libres: Epistemología y Metodología de la PsicologíaFacultad de Psicologí

Aerobic growth of Rhodococcus aetherivorans BCP1 using selected naphthenic acids as the sole carbon and energy sources

Naphthenic acids (NAs) are an important group of toxic organic compounds naturally occurring in hydrocarbon deposits. This work shows that Rhodococcus aetherivorans BCP1 cells not only utilize a mixture of eight different NAs (8XNAs) for growth but they are also capable of marked degradation of two model NAs, cyclohexanecarboxylic acid (CHCA) and cyclopentanecarboxylic acid (CPCA) when supplied at concentrations from 50 to 500 mgL-1. The growth curves of BCP1 on 8XNAs, CHCA, and CPCA showed an initial lag phase not present in growth on glucose, which presumably was related to the toxic effects of NAs on the cell membrane permeability. BCP1 cell adaptation responses that allowed survival on NAs included changes in cell morphology, production of intracellular bodies and changes in fatty acid composition. Transmission electron microscopy (TEM) analysis of BCP1 cells grown on CHCA or CPCA showed a slight reduction in the cell size, the production of EPS-like material and intracellular electron-transparent and electron-dense inclusion bodies. The electron-transparent inclusions increased in the amount and size in NA-grown BCP1 cells under nitrogen limiting conditions and contained storage lipids as suggested by cell staining with the lipophilic Nile Blue A dye. Lipidomic analyses revealed significant changes with increases of methyl-branched (MBFA) and polyunsaturated fatty acids (PUFA) examining the fatty acid composition of NAs-growing BCP1 cells. PUFA biosynthesis is not usual in bacteria and, together with MBFA, can influence structural and functional processes with resulting effects on cell vitality. Finally, through the use of RT (Reverse Transcription)-qPCR, a gene cluster (chcpca) was found to be transcriptionally induced during the growth on CHCA and CPCA. Based on the expression and bioinformatics results, the predicted products of the chcpca gene cluster are proposed to be involved in aerobic NA degradation in R. aetherivorans BCP1. This study provides first insights into the genetic and metabolic mechanisms allowing a Rhodococcus strain to aerobically degrade NAs