Differential effects of two anti-apo-cytochrome c-specific monoclonal antibodies on the function of apo-cytochrome c-specific murine T cell clones.

A murine monoclonal antibody (SJL 2-4) specific for the antigen apo-cytochrome c was shown to inhibit both antigen-induced proliferation and lymphokine secretion by an apo-cytochrome c-specific BALB/c helper T cell clone. The inhibition was specific because additional apo-cytochrome c-specific T cell clones were not inhibited by the same monoclonal antibody. Time course studies of the inhibition indicated that the initial 8 hr of contact between T cell clones and antigen-presenting cells were critical for activation of the T cell clones. Inhibition of T cell functions by antigen-specific antibodies appeared to correlate with the antibody-antigen binding constant because a second monoclonal antibody (Cyt-1-59), with identical specificity but with a lower affinity constant for apo-cytochrome c, had very little inhibitory effect on the proliferation or lymphokine secretion of apo-cytochrome c-specific T cell clones.

Proton translocation by cytochrome c oxidase reconstituted into proteoliposomes

Cytochrome c oxidase .inserted into proteoliposomes translocates protons with a stoichiometry of approx-, imately 0.4-0.6 H+/e- in the presence of valinomycin plus pottasium. The existance .ofsuchproton translocation is .supportedby experiments with lauryl maltoside which abolished the pulses but~~d not inhibit cyt. c binding .or oxidase turnover. Pulses with K3FeCN6 did not induce acidification further supporting vectorial proton transport by cyt ..aa3 . Upon lowering the ionic strength and pulsing with ferrocytochrome c, H+/eratios increased. This increase is attributed to scaler proton release consequent upon cyt.c-phospholipid binding. Oxygen pulses at low ionic strength however did not exhibit this large scaler increase in H+/e- ratios.A-small increase was observed upon .02 pul'sing at·low ionic strengt.h. This increase was KeN and, ,pcep sensitive and thus possibly due to a redox linked scaler deprotonation. Increases in the H+/e- ratio also occurred ifp~lses ,were performed in the presence of nonactin rather.than valinomycin. The fluorescent pH indicator pyranine was internally trapped inaa3 conta~ning "proteoliposomes. Internal alkalinization, as mon,itored by pyranine fluorescence leads to a of approx.imately 0.35 units, which is proportional to electron flux. This internal alkalinization was also DCCD sensitive, being inhibited by approximately 50%. This 50% inhibition of internal alkalinization supports the existance of vectorial proton transport.

The Synthesis of Imidazole Fatty Acid Conjugates as Inhibitors of Apoptosis

Ionizing radiation is known to initiate apoptosis in mammalian cells by causing the transformation of cytochrome c into a peroxidase, which results in the specific peroxidation of the mitochondrial phospholipid cardiolipin. Here we report the design and synthesis of 8 imidazole fatty acid derivatives that bind to the cyt c:CL complex and inhibit the peroxidase activity required for the initiation of apoptosis. We postulate that imidazole acts as a sixth ligand to the haem iron and stops the interaction with H2O2. Two mitochondrially directed analogues (3-hydroxypropyl)triphenylphosphonium esters) of 12-imidazole-stearic acid and 12-imidazole-oleic acid not only were demonstrated to be peroxidase inhibitors in vitro, but were also extraordinarily effective in protecting mice from lethal doses (9 Gy) of ionization radiation. We studied the structure activity relationship to a group of triphenyl phosphonium derivatives containing imidazole at different positions on the fatty acid chain, and observed that the C8-imidazole stearate analogue had marginally better activity than the others. But overall, the structure activity result were remarkable “flat” with all compounds prepared having rather similar inhibitory strength. We also synthesized carnitine mono and di-esters of 12-imidazole fatty acids but full biological data is not yet available for these compounds.

Potencial del Séptimo Programa Marco de Investigación y Desarrollo Tecnológico -7pm- en el fomento de la colaboración internacional para el desarrollo entre Colombia y la Unión Europea en materia científica y tecnológica

Es preciso que Colombia se muestre ante la U.E como un socio estratégico para el desarrollo de sus intereses científicos y tecnológicos, lo cual es posible exhibiendo importantes resultados en el Séptimo Programa Marco (7PM), tanto en el número de proyectos avalados como en la excelencia contenida en los mismos. Esto conducirá a fortalecer la dinámica de colaboración internacional en CyT entre estos dos actores.

Actituds de CTS de professorat en formació inicial de ciències i humanitats : la debilitat de la formació científica. 'Actitudes CTS de profesores en formación inicial de ciencias y humanidades : la debilidad de la formación científica'.

Resumen tomado del autor

Evaluación de resultados de un programa en salud oral en una población capitada infantil en un centro ambulatorio entre 2009-2012

El propósito de este estudio fue analizar los resultados de una intervención primaria en salud oral de una población infantil entre edades de 7 a 12 años y establecer el comportamiento presentado en la población estudiada con respecto al índice internacional de salud oral COE Y COP, determinando aumento o disminución luego de la intervención. Para ello se utilizó un instrumento de recolección de datos, posterior a la observación de los registros clínicos, logrando conocer las características de las variables planteadas en el estudio en relación al Índice de Salud Oral COE y COP – D al inicio, final y comparativo de la intervención; número de eventos requeridos para la intervención, adherencia y cambios en patrón de morbilidad luego de la intervención. De acuerdo con los resultados se encontró que el comportamiento presentado en la población estudiada con respecto al índice de salud oral COE Y COP muestra una disminución que luego del análisis de resultados concluye con el cumplimiento de la meta internacional establecida por la OMS, estableciendo como objetivo para América Latina un COP-D de 1 a 2.9 para el año 2015; lo cual para esta investigación demuestra efectividad de la intervención al obtener un índice COP-D de 2,67.

Diplomacia científica y tecnológica hacia el desarrollo de un régimen internacional

El trabajo se estructura como sigue. El primer capitulo se concentra en resaltar, sobre la base de elementos del análisis de regímenes internacionales, las nuevas características del SI relacionadas con el fenómeno científico-tecnológico. Entre ellos, se abordan dos de las principales dinámicas más influenciadas por la CyT: la competitividad y el desarrollo social. Posteriormente, una sección central y prioritaria del trabajo, estudia el tema por vía de la agenda temática global y el nuevo marco normativo internacional. En esta parte se hace una identificación, uno a uno, de la forma en que estos asuntos se manifiestan en los acuerdos internacionales más significativos. Para cerrar el capitulo, se complementa con una referencia a la construcción de institucionalidad internacional y el papel de los organismos multilaterales del nivel global y regional. El segundo capitulo se dedica enteramente a proponer el alcance, los propósitos y las formas en que se potencia la DCyT y en que contribuye a la capacidad de los Estados para responder resueltamente en el escenario internacional.

Políticas y resultados de ciencia y tecnología en Colombia

Este artículo muestra la relación existente entre las políticas de Ciencia y Tecnología (CyT) y los resultados que éstas han producido a través del gasto en CyT, como indicador de insumo, y de las publicaciones, como indicador producto. El documento describe el proceso histórico que ha tenido el sistema a través de la construcción y acumulación de capacidades, éste es dividido en cuatro etapas. Por su parte, el gasto en CyT presenta un aumento de recursos hasta 1996, a partir de allí se da un decrecimiento. Este gasto proviene, en su mayoría, del sector público a través de créditos externos. Las publicaciones muestran un rendimiento sobresaliente de Colombia en términos de crecimiento, aunque los números absolutos sean todavía muy pequeños. Dichas tasas de crecimiento muestran una correspondencia con la financiación de la CyT y con la acumulación de capacidades del sistema de innovación.

Zea mays annexins modulate cytosolic free Ca2+ and generate a Ca2+-permeable conductance

Regulation of reactive oxygen species and cytosolic free calcium ([Ca2+](cyt)) is central to plant function. Annexins are small proteins capable of Ca2+-dependent membrane binding or membrane insertion. They possess structural motifs that could support both peroxidase activity and calcium transport. Here, a Zea mays annexin preparation caused increases in [Ca2+] cyt when added to protoplasts of Arabidopsis thaliana roots expressing aequorin. The pharmacological profile was consistent with annexin activation (at the extracellular plasma membrane face) of Arabidopsis Ca2+-permeable nonselective cation channels. Secreted annexins could therefore modulate Ca2+ influx. As maize annexins occur in the cytosol and plasma membrane, they were incorporated at the intracellular face of lipid bilayers designed to mimic the plasma membrane. Here, they generated an instantaneously activating Ca2+-permeable conductance at mildly acidic pH that was sensitive to verapamil and Gd3+ and had a Ca2+-to-K+ permeability ratio of 0.36. These results suggest that cytosolic annexins create a Ca2+ influx pathway directly, particularly during stress responses involving acidosis. A maize annexin preparation also demonstrated in vitro peroxidase activity that appeared independent of heme association. In conclusion, this study has demonstrated that plant annexins create Ca2+-permeable transport pathways, regulate [Ca2+] cyt, and may function as peroxidases in vitro.

Phylogeny, species limits, and biogeography of the Brazilian lizards of the genus Eurolophosaurus (Squamata : Tropiduridae) as inferred from mitochondrial DNA sequences

Phylogenetic relationships and divergence times for 10 populations of the three recognized ""species"" of Brazilian lizards of genus Eurolophosaurus were estimated from 1229 bp of cyt b, COI, 12S, and 16S rRNA mitochondrial gene segments. Eurolophosaurus is monophyletic and the basal split within the genus separates E divaricatus from a clade comprising E amathites and E nanuzae. Three populations of E divaricatus, which occurs along the western bank of Rio S (a) over tildeo Francisco, were consistently grouped together. Oil the east bank of the river, E amathites and E nanuzae from state of Bahia were recovered as the sister group of E nanuzae populations from state of Minas Gerais. The paraphyly of E nanuzae and the high divergence levels among populations of E divaricatus strongly suggest that species limits in Eurolophosaurus should be revised. Even considering an extreme evolutionary rate of 2.8% sequence divergence per million years for the four gene segments analyzed together, E. divaricatus would have separated from the two other species by at least 5.5 my ago, and E. amathites from E nanuzae populations from Bahia and Minas Gerais, respectively, by 1.5 and 3.5 my. The paleolacustrine hypothesis and changes in the course of the river potentially explain faunal divergence in the area, but divergences are much older than previously admitted. (C) 2007 Elsevier Inc. All rights reserved.

Coalescent analysis of mtDNA indicates Pleistocene divergence among three species of howler monkey (Alouatta spp.) and population subdivision within the Atlantic Coastal Forest species, A. guariba

We have used coalescent analysis of mtDNA cytochrome b (cyt b) sequences to estimate times of divergence of three species of Alouatta-A. caraya, A. belzebul, and A. guariba-which are in close geographic proximity. A. caraya is inferred to have diverged from the A. guariba/A. belzebul clade approximately 3.83 million years ago (MYA), with the later pair diverging approximately 1.55 MYA. These dates are much more recent than previous dates based on molecular-clock methods. In addition, analyses of new sequences from the Atlantic Coastal Forest species A. guariba indicate the presence of two distinct haplogroups corresponding to northern and southern populations with both haplogroups occurring in sympatry within Sao Paulo state. The time of divergence of these two haplogroups is estimated to be 1.2 MYA and so follows quite closely after the divergence of A. guariba and A. belzebul. These more recent dates point to the importance of Pleistocene environmental events as important factors in the diversification of A. belzebul and A. guariba. We discuss the diversification of the three Alouatta species in the context of recent models of climatic change and with regard to recent molecular phylogeographic analyses of other animal groups distributed in Brazil.

Genetic structure, phylogeny, and biogeography of Brazilian eyelid-less lizards of genera Calyptommatus and Nothobachia (Squamata, Gymnophthalmidae) as inferred from mitochondrial DNA sequences

Calyptommatus and Nothobachia genera of gymnophthalmid lizards are restricted to sandy open habitats on Sao Francisco River margins, northeastern Brazil. Phylogenetic relationships and geographic distribution of the four recognized species of Calyptommatus were analyzed from partial mitochondrial cyt b, 12S, and 16S rRNA genes sequencing, taking allopatric populations of the monotypic Nothobachia ablephara as the outgroup. In Calyptommatus a basal split separated C. sinebrachiatus, a species restricted to the eastern bank of the river, from the three other species. In this clade, C. confusionibus, found on western margin, was recovered as the sister group of the two other species, C. leiolepis and C. nicterus, from opposite margins. According to approximate date estimations, C. sinebrachiatus would have separated from the other congeneric species by 4.4-6.5 my, and C. nicterus, also from eastern bank, would be diverging by 1.8-2.6 my from C. leiolepis, the sister species on the opposite margin. C. confusionibus and C. leiolepis, both from western sandy areas, would be differentiating by 2.8-5.0 my. Divergence times of about 3.0-4.0 my were estimated for allopatric populations of Nothobachia restricted to western margin. Significant differences in 16S rRNA secondary structure relatively to other vertebrates are reported. Distinct evolutionary patterns are proposed for different taxa in those sandy areas, probably related to historical changes in the course of Sao Francisco River. (C) 2010 Elsevier Inc. All rights reserved.

Mitochondrial DNA Diversity of Orchid Bee Euglossa fimbriata (Hymenoptera: Apidae) Populations Assessed by PCR-RFLP

Euglossa fimbriata is a euglossine species widely distributed in Brazil and occurring primarily in Atlantic Forest remnants. In this study, the genetic mitochondrial structure of E. fimbriata from six Atlantic Forest fragments was studied by RFLP analysis of three PCR-amplified mtDNA gene segments (16S, COI-COII, and cyt b). Ten composite haplotypes were identified, six of which were exclusive and represented singleton mitotypes. Low haplotype diversity (0.085-0.289) and nucleotide diversity (0.000-0.002) were detected within samples. AMOVA partitioned 91.13% of the overall genetic variation within samples and 8.87% (I center dot(st) = 0.089; P < 0.05) among samples. Pairwise comparisons indicated high levels of differentiation among some pairs of samples (I center dot(st) = 0.161-0.218; P < 0.05). These high levels indicate that these populations of E. fimbriata, despite their highly fragmented landscape, apparently have not suffered loss of genetic variation, suggesting that this particular population is not currently endangered.

Phylogenetic relationships, diversification and biogeography in Neotropical Brotogeris parakeets

Aim We present a molecular phylogenetic analysis of Brotogeris (Psittacidae) using several distinct and complementary approaches: we test the monophyly of the genus, delineate the basal taxa within it, uncover their phylogenetic relationships, and finally, based on these results, we perform temporal and spatial comparative analyses to help elucidate the historical biogeography of the Neotropical region. Location Neotropical lowlands, including dry and humid forests. Methods Phylogenetic relationships within Brotogeris were investigated using the complete sequences of the mitochondrial genes cyt b and ND2, and partial sequences of the nuclear intron 7 of the gene for Beta Fibrinogen for all eight species and 12 of the 17 taxa recognized within the genus (total of 63 individuals). In order to delinetae the basal taxa within the genus we used both molecular and plumage variation, the latter being based on the examination of 597 skin specimens. Dates of divergence and confidence intervals were estimated using penalized likelihood. Spatial and temporal comparative analyses were performed including several closely related parrot genera. Results Brotogeris was found to be a monophyletic genus, sister to Myiopsitta. The phylogenetic analyses recovered eight well-supported clades representing the recognized biological species. Although some described subspecies are diagnosably distinct based on morphology, there was generally little intraspecific mtDNA variation. The Amazonian species had different phylogenetic affinities and did not group in a monophyletic clade. Brotogeris diversification took place during the last 6 Myr, the same time-frame as previously found for Pionus and Pyrilia. Main conclusions The biogeographical history of Brotogeris implies a dynamic history for South American biomes since the Pliocene. It corroborates the idea that the geological evolution of Amazonia has been important in shaping its biodiversity, argues against the idea that the region has been environmentally stable during the Quaternary, and suggests dynamic interactions between wet and dry forest habitats in South America, with representatives of the Amazonian biota having several independent close relationships with taxa endemic to other biomes.