Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
Mais filtros










Intervalo de ano de publicação
2.
Public Underst Sci ; 24(6): 641-57, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24164746

RESUMO

In this article we explore how the Spanish written press--ABC, La Vanguardia, and Blanco y Negro--and the official newsreel No-Do, created and disseminated a narrative about heart transplantations at the end of the 1960s. We consider how Franco's regime used Christiaan Barnard's heart transplants to legitimize the Spanish dictatorship and as a means of signifying scientific progress, modernization and national pride. The Spanish press created the plot of the first transplantations like that of a television series, presenting daily installments on the patients' progress, dramatizing the stories and ensuring the public's emotional attachment. The three main characters in the story: donors, patients and surgeons, formed a symbolic, indivisible narrative triangle endowed with singular meaning. This Spanish narrative of organ transplant technology was deployed through what we have called "a tale of two countries", that, emulating the South African's success, constructed in Martínez-Bordiú, Franco's son-in-law, a home-grown, masculine scientific personality capable of performing heart surgery and endorsing Franco's investment in scientific modernization.


Assuntos
Cultura , Transplante de Coração/história , Pacientes/história , Médicos/história , Política , História do Século XX , Humanos , África do Sul , Espanha
3.
PLoS One ; 9(1): e83615, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24421895

RESUMO

Multi-decadal increase in shell removal by tourists, a process that may accelerate degradation of natural habitats, was quantified via two series of monthly surveys, conducted thirty years apart (1978-1981 and 2008-2010) in one small embayment on the Mediterranean coast of the Iberian Peninsula. Over the last three decades, the local tourist arrivals have increased almost three-fold (2.74), while the area has remained unaffected by urban encroachment and commercial fisheries. During the same time interval the abundance of mollusk shells along the shoreline decreased by a comparable factor (2.62) and was significantly and negatively correlated with tourist arrivals (r = -0.52). The strength of the correlation increased when data were restricted to months with high tourist arrivals (r = -0.72). In contrast, the maximum monthly wave energy (an indirect proxy for changes in rate of onshore shell transport) was not significantly correlated with shell abundance (r = 0.10). Similarly, rank dominance of common species, drilling predation intensity, and body size-frequency distribution patterns have all remained stable over recent decades. A four-fold increase in global tourist arrivals over the last 30 years may have induced a comparable worldwide acceleration in shell removal from marine shorelines, resulting in multiple, currently unquantifiable, habitat changes such as increased beach erosion, changes in calcium carbonate recycling, and declines in diversity and abundance of organisms, which are dependent on shell availability.


Assuntos
Exoesqueleto/fisiologia , Bivalves/fisiologia , Ecossistema , Internacionalidade , Viagem , Animais , Biodiversidade , Geografia , Tamanho do Órgão , Estações do Ano , Espanha , Especificidade da Espécie , Temperatura , Fatores de Tempo , Movimentos da Água
4.
PLoS One ; 8(10): e78101, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24205110

RESUMO

The stress protein Nupr1 is a highly basic, multifunctional, intrinsically disordered protein (IDP). MSL1 is a histone acetyl transferase-associated protein, known to intervene in the dosage compensation complex (DCC). In this work, we show that both Nupr1 and MSL1 proteins were recruited and formed a complex into the nucleus in response to DNA-damage, which was essential for cell survival in reply to cisplatin damage. We studied the interaction of Nupr1 and MSL1, and their binding affinities to DNA by spectroscopic and biophysical methods. The MSL1 bound to Nupr1, with a moderate affinity (2.8 µM) in an entropically-driven process. MSL1 did not bind to non-damaged DNA, but it bound to chemically-damaged-DNA with a moderate affinity (1.2 µM) also in an entropically-driven process. The Nupr1 protein bound to chemically-damaged-DNA with a slightly larger affinity (0.4 µM), but in an enthalpically-driven process. Nupr1 showed different interacting regions in the formed complexes with Nupr1 or DNA; however, they were always disordered ("fuzzy"), as shown by NMR. These results underline a stochastic description of the functionality of the Nupr1 and its other interacting partners.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Histona Acetiltransferases/metabolismo , Proteínas de Neoplasias/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Linhagem Celular Tumoral , Sobrevivência Celular/genética , Sobrevivência Celular/fisiologia , Cisplatino/toxicidade , Dano ao DNA/genética , Dano ao DNA/fisiologia , Reparo do DNA/efeitos dos fármacos , Reparo do DNA/genética , Imunofluorescência , Histona Acetiltransferases/genética , Humanos , Espectroscopia de Ressonância Magnética , Proteínas de Neoplasias/genética , Ligação Proteica
5.
Curr Protein Pept Sci ; 14(8): 658-68, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24106962

RESUMO

HIV-1, the agent responsible for AIDS, belongs to the retrovirus family. Assembly of the immature HIV-1 capsid occurs through the controlled polymerization of the Gag polyprotein, which is transported to the plasma membrane of infected cells, where morphogenesis of the immature, non-infectious virion occurs. Moreover, the mature capsid of HIV-1 is formed by the assembly of copies of the capsid protein (CA), which results, among other proteins, from cleavage of Gag. The C-terminal domain of CA (CTD) can homodimerize, and most of the dimerization interface is formed by a single α-helix from each monomer. Assembly of the HIV-1 capsid critically depends on CA-CA interactions, including CTD interaction with itself and with the N-terminal domain of CA (NTD). This review will report on recent advances for the search of small organic compounds and peptides that have been designed in the last four years to hamper CA assembly. Most of the molecules have been proved to interact with CA; such molecules aim to disrupt and/or alter the oligomerization capability of CTD and/or NTD.


Assuntos
Fármacos Anti-HIV/química , Fármacos Anti-HIV/farmacologia , Proteínas do Capsídeo/antagonistas & inibidores , Desenho de Fármacos , Infecções por HIV/tratamento farmacológico , HIV-1/efeitos dos fármacos , Sequência de Aminoácidos , Proteínas do Capsídeo/química , Proteínas do Capsídeo/metabolismo , Infecções por HIV/virologia , HIV-1/química , Humanos , Modelos Moleculares , Dados de Sequência Molecular , Terapia de Alvo Molecular , Peptídeos/química , Peptídeos/farmacologia , Estrutura Terciária de Proteína/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia
6.
PLoS One ; 8(7): e69307, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23922699

RESUMO

The phosphotransferase system (PTS) is involved in the use of carbon sources in bacteria. Bacillus sphaericus, a bacterium with the ability to produce insecticidal proteins, is unable to use hexoses and pentoses as the sole carbon source, but it has ptsHI genes encoding the two general proteins of the PTS: enzyme I (EI) and the histidine phosphocarrier (HPr). In this work, we describe the biophysical and structural properties of HPr from B. sphaericus, HPr(bs), and its affinity towards EI of other species to find out whether there is inter-species binding. Conversely to what happens to other members of the HPr family, HPr(bs) forms several self-associated species. The conformational stability of the protein is low, and it unfolds irreversibly during heating. The protein binds to the N-terminal domain of EI from Streptomyces coelicolor, EIN(sc), with a higher affinity than that of the natural partner of EIN(sc), HPr(sc). Modelling of the complex between EIN(sc) and HPr(bs) suggests that binding occurs similarly to that observed in other HPr species. We discuss the functional implications of the oligomeric states of HPr(bs) for the glycolytic activity of B. sphaericus, as well as a strategy to inhibit binding between HPr(sc) and EIN(sc).


Assuntos
Bacillus/metabolismo , Proteínas de Bactérias/metabolismo , Sistema Fosfotransferase de Açúcar do Fosfoenolpiruvato/metabolismo , Proteínas de Bactérias/química , Calorimetria , Histidina , Temperatura Alta , Hidrodinâmica , Concentração de Íons de Hidrogênio , Modelos Moleculares , Peptídeos , Sistema Fosfotransferase de Açúcar do Fosfoenolpiruvato/química , Fosforilação , Ligação Proteica , Desnaturação Proteica , Dobramento de Proteína , Estrutura Secundária de Proteína , Espectrometria de Fluorescência , Streptomyces coelicolor/metabolismo , Termodinâmica
7.
Arch Esp Urol ; 66(3): 305-7, 2013 Apr.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-23648751

RESUMO

OBJECTIVE: To report a case of paratesticular rhadomyosarcoma and to perform a bibliographic review. METHODS: We report the case of a 16-year-old male referred to our Department because of a left paratesticular hard tumor with progressive growth. Ultrasound examination showed a paratesticular heterogeneous mass with Internal flow on Doppler. RESULTS: The patient underwent left inguinal orchiectomy, with pathological diagnosis of rhabdomyosarcoma. He refused adjuvant chemotherapy. After being disease-free for 13 months, he presented with left colic pain. Ultrasound and CT examinations showed a left paraaortic retroperitoneal mass causing grade III ureterohydronephrosis, and lung metastases. Despite rescue chemotherapy treatment, there was no response and the abdominal mass progressed. A surgical approach was not possible since patient showed a rapid clinical worsening leading to his death a few weeks later. CONCLUSIONS: Paratesticular sarcomas are very uncommon tumors with poor prognosis.


Assuntos
Orquiectomia , Rabdomiossarcoma , Quimioterapia Adjuvante , Humanos , Neoplasias Pulmonares , Neoplasias Testiculares
8.
Arch. esp. urol. (Ed. impr.) ; 66(3): 305-307, abr. 2013. ilus
Artigo em Espanhol | IBECS | ID: ibc-111819

RESUMO

OBJETIVO: Presentar un caso de radomiosarcoma paratesticular y revisión de la literatura. MÉTODOS: Describimos el caso de un varón de 16 años remitido a nuestro servicio por masa paratesticular izquierda de crecimiento progresivo, con imagen ecográfica de tumoración paratesticular heterogénea con flujo Doppler en su interior. RESULTADOS: Se realizó orquiectomía izquierda, con diagnóstico de rabdomiosarcoma. El paciente rechazó el tratamiento quimioterápico adyuvante. Tras 13 meses libre de enfermedad, reingresó por dolor cólico izquierdo detectándose en ecografía y TC una masa retroperitoneal paraaórtica izquierda que condicionaba uréterohidronefrosis grado III, y metástasis pulmonares. A pesar de instaurarse quimioterapia de rescate, no respondió presentando rápida progresión de la masa abdominal con importante deterioro general que no permitió el abordaje quirúrgico, siendo éxitus a las pocas semanas. CONCLUSIÓN: Los sarcomas paratesticulares son tumores infrecuentes y de mal pronóstico(AU)


OBJECTIVE: To report a case of paratesticular rhadomyosarcoma and to perform a bibliographic review. METHODS: We report the case of a 16-year-old male referred to our Department because of a left paratesticular hard tumor with progressive growth. Ultrasound examination showed a paratesticular heterogeneous mass with Internal flow on Doppler. RESULTS: The patient underwent left inguinal orchiectomy, with pathological diagnosis of rhabdomyosarcoma. He refused adjuvant chemotherapy. After being disease-free for 13 months, he presented with left colic pain. Ultrasound and CT examinations showed a left paraaortic retroperitoneal mass causing grade III ureterohydronephrosis, and lung metastases. Despite rescue chemotherapy treatment, there was no response and the abdominal mass progressed. A surgical approach was not possible since patient showed a rapid clinical worsening leading to his death a few weeks later. CONCLUSIONS: Paratesticular sarcomas are very uncommon tumors with poor prognosis(AU)


Assuntos
Humanos , Masculino , Adulto Jovem , Miossarcoma/complicações , Miossarcoma/diagnóstico , Orquiectomia/instrumentação , Orquiectomia/métodos , Neoplasias Testiculares/complicações , Neoplasias Testiculares/diagnóstico , Neoplasias Testiculares/cirurgia , Dor/complicações , Dor/diagnóstico , Dor/etiologia , Miossarcoma/fisiopatologia , Miossarcoma/cirurgia , Miossarcoma , Orquiectomia/normas , Orquiectomia/tendências , Orquiectomia , Neoplasias Testiculares/fisiopatologia , Neoplasias Testiculares
9.
Biochemistry ; 51(37): 7393-402, 2012 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-22909257

RESUMO

The phosphotransferase system (PTS) controls the use of sugars in bacteria. The PTS is ubiquitous in bacteria, but it does not occur in plants and animals; it modulates catabolite repression, intermediate metabolism, gene expression, and chemotaxis. Its uniqueness and pleiotropic function make the PTS an attractive target for new antibacterial drugs. The PTS is constituted of two general proteins, namely, enzyme I (EI) and the histidine phosphocarrier (HPr), and various sugar-specific permeases. EI has two domains: the N-terminal domain (EIN), which binds to HPr, and the C-terminal domain (EIC), which contains the dimerization interface. In this work, we determined the binding affinities of peptides derived from EIN of Streptomyces coelicolor (EIN(sc)) against HPr of the same organism (HPr(sc)), by using nuclear magnetic resonance and isothermal titration calorimetry techniques. Furthermore, we measured the affinity of EIN(sc) for (i) a peptide derived from HPr(sc), containing the active-site histidine, and (ii) other peptides identified previously by phage display and combinatorial chemistry in Escherichia coli [Mukhija, S. L., et al (1998) Eur. J. Biochem. 254, 433-438; Mukhija, S., and Erni, B. (1997) Mol. Microbiol. 25, 1159-1166]. The affinities were in the range of ~10 µM, being slightly higher for the binding of EIN(sc) with peptides derived from HPr(sc), phage display, or combinatorial chemistry (K(D) ~ 5 µM). Because the affinity of intact EIN(sc) for the whole HPr(sc) is 12 µM, we suggest that the assayed peptides might be considered as good hit compounds for inhibiting the interaction between HPr(sc) and EIN(sc).


Assuntos
Sistemas de Transporte de Aminoácidos/antagonistas & inibidores , Antibacterianos/química , Proteínas de Bactérias/antagonistas & inibidores , Inibidores Enzimáticos/química , Peptídeos/química , Sistema Fosfotransferase de Açúcar do Fosfoenolpiruvato/antagonistas & inibidores , Fosfotransferases (Aceptor do Grupo Nitrogenado)/antagonistas & inibidores , Streptomyces coelicolor/enzimologia , Sistemas de Transporte de Aminoácidos/química , Sistemas de Transporte de Aminoácidos/metabolismo , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Técnicas de Química Combinatória , Inibidores Enzimáticos/metabolismo , Inibidores Enzimáticos/farmacologia , Peptídeos/metabolismo , Peptídeos/farmacologia , Fosfoenolpiruvato/química , Fosfoenolpiruvato/metabolismo , Sistema Fosfotransferase de Açúcar do Fosfoenolpiruvato/química , Sistema Fosfotransferase de Açúcar do Fosfoenolpiruvato/metabolismo , Fosforilação/efeitos dos fármacos , Fosforilação/fisiologia , Fosfotransferases (Aceptor do Grupo Nitrogenado)/química , Fosfotransferases (Aceptor do Grupo Nitrogenado)/metabolismo , Estrutura Terciária de Proteína , Streptomyces coelicolor/química
10.
Arch Biochem Biophys ; 526(1): 44-53, 2012 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-22809892

RESUMO

The phosphotransferase system (PTS) is involved in the use of carbon sources in bacteria. It is formed by two general proteins: enzyme I (EI) and the histidine phosphocarrier (HPr), and various sugar-specific permeases. EI is formed by two domains, with the N-terminal domain (EIN) being responsible for the binding to HPr. In low-G+C Gram-positive bacteria, HPr becomes phosphorylated not only by phosphoenolpyruvate (PEP) at the active-site histidine, but also by ATP at a serine. In this work, we have characterized: (i) the stability and binding affinities between the active-site-histidine phosphorylated species of HPr and the EIN from Streptomyces coelicolor; and (ii) the stability and binding affinities of the species involving the phosphorylation at the regulatory serine of HPr(sc). Our results show that the phosphorylated active-site species of both proteins are less stable than the unphosphorylated counterparts. Conversely, the Hpr-S47D, which mimics phosphorylation at the regulatory serine, is more stable than wild-type HPr(sc) due to helical N-capping effects, as suggested by the modeled structure of the protein. Binding among the phosphorylated and unphosphorylated species is always entropically driven, but the affinity and the enthalpy vary widely.


Assuntos
Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Domínio Catalítico , Sistema Fosfotransferase de Açúcar do Fosfoenolpiruvato/química , Sistema Fosfotransferase de Açúcar do Fosfoenolpiruvato/metabolismo , Fosfoproteínas/química , Fosfoproteínas/metabolismo , Streptomyces coelicolor/enzimologia , Proteínas de Bactérias/genética , Estabilidade Enzimática , Ligação de Hidrogênio , Mutagênese Sítio-Dirigida , Mutação , Sistema Fosfotransferase de Açúcar do Fosfoenolpiruvato/genética , Fosfoproteínas/genética , Fosforilação , Serina/metabolismo , Termodinâmica
11.
Biochim Biophys Acta ; 1824(8): 991-1001, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22609416

RESUMO

E2 ubiquitin conjugases are ~20kDa enzymes involved in ubiquitination processes in eukaryotes. The E2s are responsible for the transference of ubiquitin (Ub) to E3 enzymes, which finally transfer Ub to diverse target proteins, labelling them for degradation, localization and regulation. Although their functions are relatively well-characterized, their conformational stabilities are poorly known. In this work, we have used, as a model for our biophysical and binding studies, the E2-C from Carassius auratus (goldfish), a homologue of the human ubiquitin conjugase UbcH10. E2-C(ca) was a monomeric protein with an elongated shape; moreover, the protein was only marginally stable within a narrow pH range (from 6.0 to 8.0). We also explored the binding of E2-C(ca) towards non-canonical E3 ligases. Binding of E2-C(ca) to the C terminus of murine Ring 1B (C-Ring1B), which does not contain the RING finger of the whole Ring1B, occurred with an affinity of ~400nM, as shown by fluorescence and ITC. Furthermore, binding of E2-C(ca) to C-Ring1B did not occur at its canonical E2-loops, since residues M43 and F53, far away from those loops, were involved in binding. Thus, the C-Ring1B-interacting region of E2-C(ca) comprises the first ß-strand and nearby residues.


Assuntos
Proteínas de Peixes/química , Carpa Dourada , Enzimas de Conjugação de Ubiquitina/química , Ubiquitina-Proteína Ligases/química , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Sítios de Ligação , Concentração de Íons de Hidrogênio , Modelos Moleculares , Dados de Sequência Molecular , Ligação Proteica , Estabilidade Proteica , Enzimas de Conjugação de Ubiquitina/metabolismo , Ubiquitina-Proteína Ligases/metabolismo
12.
PLoS One ; 7(4): e34576, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22496828

RESUMO

We report quantitative analyses of drilling predation on the free-living, tube-dwelling serpulid polychaete Ditrupa arietina from the Cope Cabo marine succession (Pliocene, Spain). Tubes of D. arietina are abundant in the sampled units: 9 bulk samples from 5 horizons yielded ~5925 specimens of D. arietina. Except for fragmentation, tubes were well preserved. Complete specimens ranged from 3.1 to 13.4 mm in length and displayed allometric growth patterns, with larger specimens being relatively slimmer. Drilled Ditrupa tubes were observed in all samples. Drillholes, identified as Oichnus paraboloides, were characterized by circular to elliptical outline (drillhole eccentricity increased with its diameter), parabolic vertical profile, outer diameter larger than inner diameter, penetration of one tube wall only, narrow range of drill-hole sizes, and non-random (anterior) distribution of drillholes. A total of 233 drilled specimens were identified, with drilling frequencies varying across horizons from 2.7% to 21% (3.9% for pooled data). Many tube fragments were broken across a drillhole suggesting that the reported frequencies are conservative and that biologically-facilitated (drill-hole induced) fragmentation hampers fossil preservation of complete serpulid tubes. No failed or repaired holes were observed. Multiple complete drillholes were present (3.9%). Drilled specimens were significantly smaller than undrilled specimens and tube length and drill-hole diameter were weakly correlated. The results suggest that drillholes were produced by a size-selective, site-stereotypic predatory organism of unknown affinity. The qualitative and quantitative patterns reported here are mostly consistent with previous reports on recent and fossil Ditrupa and reveal parallels with drilling patterns documented for scaphopod mollusks, a group that is ecologically and morphologically similar to Ditrupa. Consistent with previous studies, the results suggest that free-dwelling serpulid polychaetes are preyed upon by drilling predators and may provide a viable source of data on biotic interactions in the fossil record.


Assuntos
Cadeia Alimentar , Moluscos , Poliquetos , Animais , Espanha
13.
PLoS One ; 6(9): e23877, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21931621

RESUMO

Virus capsid assembly constitutes an attractive target for the development of antiviral therapies; a few experimental inhibitors of this process for HIV-1 and other viruses have been identified by screening compounds or by selection from chemical libraries. As a different, novel approach we have undertaken the rational design of peptides that could act as competitive assembly inhibitors by mimicking capsid structural elements involved in intersubunit interfaces. Several discrete interfaces involved in formation of the mature HIV-1 capsid through polymerization of the capsid protein CA were targeted. We had previously designed a peptide, CAC1, that represents CA helix 9 (a major part of the dimerization interface) and binds the CA C-terminal domain in solution. Here we have mapped the binding site of CAC1, and shown that it substantially overlaps with the CA dimerization interface. We have also rationally modified CAC1 to increase its solubility and CA-binding affinity, and designed four additional peptides that represent CA helical segments involved in other CA interfaces. We found that peptides CAC1, its derivative CAC1M, and H8 (representing CA helix 8) were able to efficiently inhibit the in vitro assembly of the mature HIV-1 capsid. Cocktails of several peptides, including CAC1 or CAC1M plus H8 or CAI (a previously discovered inhibitor of CA polymerization), or CAC1M+H8+CAI, also abolished capsid assembly, even when every peptide was used at lower, sub-inhibitory doses. To provide a preliminary proof that these designed capsid assembly inhibitors could eventually serve as lead compounds for development of anti-HIV-1 agents, they were transported into cultured cells using a cell-penetrating peptide, and tested for antiviral activity. Peptide cocktails that drastically inhibited capsid assembly in vitro were also able to efficiently inhibit HIV-1 infection ex vivo. This study validates a novel, entirely rational approach for the design of capsid assembly interfacial inhibitors that show antiviral activity.


Assuntos
Fármacos Anti-HIV/farmacologia , Capsídeo/efeitos dos fármacos , Capsídeo/metabolismo , Desenho de Fármacos , HIV-1/efeitos dos fármacos , HIV-1/metabolismo , Fragmentos de Peptídeos/farmacologia , Sequência de Aminoácidos , Fármacos Anti-HIV/química , Fármacos Anti-HIV/metabolismo , Sítios de Ligação , Proteínas do Capsídeo/química , Proteínas do Capsídeo/metabolismo , Linhagem Celular , HIV-1/patogenicidade , Modelos Moleculares , Dados de Sequência Molecular , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Multimerização Proteica/efeitos dos fármacos , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Solubilidade
14.
Biomacromolecules ; 12(9): 3252-64, 2011 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-21761887

RESUMO

The C-terminal domain (CTD) of the capsid protein (CA) of HIV-1 participates both in the formation of CA hexamers and in the joining of hexamers through homodimerization to form the viral capsid. Intact CA and the CTD are able to homodimerize with similar affinity (~15 µM); CTD homodimerization involves mainly an α-helical region. We have designed peptides derived from that helix with predicted higher helical propensities than the wild-type sequence while keeping residues important for dimerization. These peptides showed a higher helicity than that of the wild-type peptide, although not as high as theoretically predicted, and proved to be able to self-associate with apparent affinities similar to that of the whole CTD. However, binding to CTD mainly occurs at the last helical region of the protein. Accordingly, most of those peptides are unable to inhibit CA polymerization in vitro. Therefore, there is a subtle tuning between monomer-monomer interactions important for CTD dimerization and the maximal helical content achieved by the wild-type sequence of the interface.


Assuntos
Proteínas do Capsídeo/química , HIV-1/química , Oligopeptídeos/química , Multimerização Proteica/efeitos dos fármacos , Proteínas Recombinantes/química , Sequência de Aminoácidos , Sítios de Ligação , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/metabolismo , Dicroísmo Circular , Dimerização , Infecções por HIV/virologia , HIV-1/metabolismo , Humanos , Cinética , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Dados de Sequência Molecular , Mutação , Oligopeptídeos/genética , Oligopeptídeos/farmacologia , Ligação Proteica , Estrutura Secundária de Proteína/efeitos dos fármacos , Estrutura Terciária de Proteína/efeitos dos fármacos , Proteínas Recombinantes/genética , Proteínas Recombinantes/farmacologia , Software , Espectrometria de Fluorescência
15.
Biochim Biophys Acta ; 1814(10): 1269-78, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21745604

RESUMO

Assembly of the mature human immunodeficiency virus type 1 (HIV-1) capsid involves the oligomerization of the capsid protein, CA. During retroviral maturation, the CA protein undergoes structural changes and forms exclusive intermolecular interfaces in the mature capsid shell, different from those in the immature precursor. The most conserved region of CA, the major homology region (MHR), is located in the C-terminal domain of CA (CTD). The MHR is involved in both immature and mature virus assembly; however, its exact function during both assembly stages is unknown. To test its conformational preferences and to provide clues on its role during CA assembly, we have used a minimalist approach by designing a peptide comprising the whole MHR (MHRpep, residues Asp152 to Ala174). Isolated MHRpep is mainly unfolded in aqueous solution, with residual structure at its C terminus. MHRpep binds to monomeric CTD with an affinity of ~30µM (as shown by fluorescence and ITC); the CTD binding region comprises residues belonging to α-helices 10 and 11. In the immature virus capsid, the MHR and α-helix 11 regions of two CTD dimers also interact [Briggs JAG, Riches JD, Glass B, Baratonova V, Zanetti G and Kräusslich H-G (2009) Proc. Natl. Acad. Sci. USA 106, 11090-11095]. These results can be considered a proof-of-concept that the conformational preferences and binding features of isolated peptides derived from virus proteins could be used to mimic early stages of virus assembly.


Assuntos
Proteínas do Capsídeo/química , Proteínas do Capsídeo/metabolismo , HIV-1 , Dobramento de Proteína , Sequência de Aminoácidos , Proteínas do Capsídeo/isolamento & purificação , Cristalografia por Raios X , HIV-1/química , Humanos , Modelos Moleculares , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Ligação Proteica/fisiologia , Multimerização Proteica , Estrutura Terciária de Proteína/fisiologia , Homologia de Sequência de Aminoácidos , Soluções , Montagem de Vírus
16.
Biomacromolecules ; 11(8): 2069-78, 2010 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-20690715

RESUMO

Assembly of the mature human immunodeficiency virus type 1 capsid involves the oligomerization of the capsid protein, CA. The C-terminal domain of CA, CTD, participates both in the formation of CA hexamers and in the joining of hexamers through homodimerization. Intact CA and the isolated CTD are able to homodimerize in solution with similar affinity (dissociation constant in the order of 10 microM); CTD homodimerization involves mainly an alpha-helical region. In this work, we show that first-generation gallic acid-triethylene glycol (GATG) dendrimers bind to CTD. The binding region is mainly formed by residues involved in the homodimerization interface of CTD. The dissociation constant of the dendrimer-CTD complexes is in the range of micromolar, as shown by ITC. Further, the affinity for CTD of some of the dendrimers is similar to that of synthetic peptides capable of binding to the dimerization region, and it is also similar to the homodimerization affinity of both CTD and CA. Moreover, one of the dendrimers, with a relatively large hydrophobic moiety at the dendritic branching (a benzoate), was able to hamper the assembly in vitro of the human immunodeficiency virus capsid. These results open the possibility of considering dendrimers as lead compounds for the development of antihuman immunodeficiency virus drugs targeting capsid assembly.


Assuntos
Fármacos Anti-HIV/farmacologia , Proteínas do Capsídeo/antagonistas & inibidores , Dendrímeros/farmacologia , HIV-1/efeitos dos fármacos , Fármacos Anti-HIV/química , Calorimetria , Dicroísmo Circular , Dendrímeros/química , Dimerização , Ácido Gálico/química , Cinética , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Polietilenoglicóis/química , Espectrometria de Fluorescência
17.
Soc Stud Sci ; 39(1): 81-112, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19569426

RESUMO

This paper examines how Spanish techno-scientific discourses and practices shaped metropolitan Spanish and colonial Guinean bodies and identities. It focuses on the range of technologies of biopower--from fingerprinting and blood testing to racial and geographic discourses--that constituted Guinean bodies in ambivalent ways during two periods: the first decades of the 20th century, and the post-Civil War period of the Francoist regime. In the first decades of the 20th century, blood tests were imposed on the local population as a legal requirement for obtaining identity cards in colonial Guinea; the identity cards offered them a severely restricted citizen status, especially if they were female. Indeed, the new blood testing technologies played a key role in efforts to control, reform and identify 'natives', less as subjects than as labouring bodies. During Franco's dictatorship, following the end of the Spanish Civil War (1939), the colonies became a space for the reconstruction of a unified Spanish national identity through two key strategies: 'detribalization' and 'hispanicization', which were carried out through a web of techno-scientific practices--in medicine and psychology as well as geography and anthropology--that included fingerprinting, blood testing, measurements of intelligence and racial discourses. Under the Franco regime, these practices not only justified violent, racist forms of exploitation, but were also used to stake a claim on Guinean colonial territories and bodies by emptying them of their existing identities and then reconstituting them under a single Spanish national identity.


Assuntos
Colonialismo/história , Relações Raciais/história , Tecnologia/história , Dermatoglifia/história , Guiné Equatorial , Testes Hematológicos/história , História do Século XX , Humanos , Grupos Raciais/classificação , Espanha
18.
Am J Public Health ; 97(9): 1563-71, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17666707

RESUMO

The implementation of radiation technologies within the British hospital system was a significant element in the establishment of the managerial organization of medicine in the interwar period. One aspect of this implementation process was that, in order to install cancer patients within the "radiotherapy factory," British medical officers of health adapted their organizational cultures from being environmentalists to being administrators of medical services. One of the consequences of this change was the accomplishment of a much more reductive approach to cancer compared with a more holistic approach to the disease.


Assuntos
Regulamentação Governamental/história , Cultura Organizacional , Administração em Saúde Pública/história , Saúde Pública/história , Radioterapia (Especialidade)/história , Sociologia Médica/história , História do Século XX , Humanos , Diretores Médicos , Serviço Hospitalar de Radiologia/história , Rádio (Elemento)/história , Rádio (Elemento)/provisão & distribuição , Reino Unido , I Guerra Mundial , II Guerra Mundial
19.
Public Underst Sci ; 14(4): 393-408, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16402492

RESUMO

NO-DO, the Spanish official newsreel produced by Franco's dictatorship (1939-1975), held a 30-year monopoly over audio-visual information in Spain from 1943 to 1975. This paper reports on an analysis of coverage of medical technologies by the Spanish Cinematic Newsreel Service, NO-DO, from 1943 to 1970. The study focuses on the changing roles played by cultural representations of medical technologies deployed in NO-DO. Our analysis shows how these representations offered a new space for the legitimization of the regime, and, more importantly, played a key role in the attempts to construct and enforce a hegemonic national identity after the Spanish Civil War (1936-1939). During the period of isolationist autocracy that ended in the mid-1950s, the images of medical technologies reinforced the idea of a self-sufficient "national space" and deepened the break with the historical past. Once the international isolation of the regime was overcome in the late 1950s and the 1960s, the representation of medical technologies contributed to establishing a Spanish national identity that mirrored the outside world, the foreign space. Finally, gender representations in NO-DO are also explored.


Assuntos
Ciência de Laboratório Médico/história , História do Século XX , Filmes Cinematográficos/história , Sistemas Políticos/história , Espanha
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...