The role of lipids in the biogenesis of integral membrane proteins

Most integral membrane proteins are cotranslationally inserted into the lipid bilayer. In prokaryotes, membrane insertion of the nascent chain takes place at the plasma membrane, whereas in eukaryotes insertion takes place into the endoplasmatic reticulum. In both kingdoms of life, however, the same membrane that acquaints the newly born membrane protein also synthesizes the bilayer lipids and thus ensures the balanced growth of the membrane as a whole. Recent evidence indicates that the lipid composition of the host membrane can determine the fate of the newborn membrane protein, as it can affect (1) the efficiency of translocation, (2) the topology of the resulting membrane protein, (3) its stability, (4) its assembly into oligomeric complexes, (5) its transport and sorting along the secretory pathway, and (6) its enzymatic activity. The lipid composition of the membrane thus can affect the biogenesis and function of integral membrane proteins at multiple steps along its biogenetic pathway. While understanding this interdependence between bilayer lipids and protein biogenesis is interesting in its own right, careful consideration of a potential host's membrane lipid composition may also allow optimization of the yield and activity of membrane proteins that are expressed in a heterologous organism. Here, we review and discuss some examples that illustrate the interdependence between bilayer lipids and the biogenesis of integral membrane protein

On the Origin of the Colour-Magnitude Relation in the Virgo Cluster

We explore the origin of the colour-magnitude relation (CMR) of early type galaxies in the Virgo cluster using spectra of very high S/N ratio for six elliptical galaxies selected along the CMR. The data are analysed using a new evolutionary stellar population synthesis model to generate galaxy spectra at the resolution given by their velocity dispersions. In particular we use a new age indicator that is virtually free of the effects of metallicity. We find that the luminosity weighted mean ages of Virgo ellipticals are greater than ~8 Gyr, and show no clear trend with galaxy luminosity. We also find a positive correlation of metallicity with luminosity, colour and velocity dispersion. We conclude that the CMR is driven primarily by a luminosity-metallicity correlation. However, not all elements increase equally with the total metallicity and we speculate that the CMR may be driven by both a total metallicity increase and by a systematic departure from solar abundance ratios of some elements along the CMR. A full understanding of the role played by the total metallicity, abundance ratios and age in generating the CMR requires the analysis of spectra of very high quality, such as those reported here, for a larger number of galaxies in Virgo and other clusters.Comment: To appear in The Astrophysical Journal Letters, 2001 April 20 (551, number 2). 5 pages and 4 figure

Inervação prostática e anestesia local em procedimentos prostáticos

The nerve supply of the human prostate is very abundant, and knowledge of the anatomy contributes to successful administration of local anesthesia. However, the exact anatomy of extrinsic neuronal cell bodies of the autonomic and sensory innervation of the prostate is not clear, except in other animals. Branches of pelvic ganglia composed of pelvic (parasympathetic) and hypogastric (sympathetic) nerves innervate the prostate. The autonomic nervous system plays an important role in the growth, maturation, and secretory function of this gland. Prostate procedures under local anesthesia, such as transurethral prostatic resections or transrectal ultrasound-guided prostatic biopsy, are safe, simple, and effective. Local anesthesia can be feasible for many special conditions including uncomplicated prostate surgery and may be particularly useful for the high-risk group of patients for whom inhalation or spinal anesthesia is inadvisable.A prostáta, uma das glândulas sexuais acessórias masculinas, possui inervação muito rica. A anatomia detalhada dos corpos neuronais extrínsecos responsáveis pela inervação autonômica e sensorial da próstata não está totalmente esclarecida, exceto em animais. A próstata é inervada pelos nervos pélvico (parassimpático) e hipogástrico (simpático), ramos dos gânglios nervosos pélvicos. O sistema nervoso autonômico possui importante papel no crescimento, maturação e na função secretora desta glândula. Alguns procedimentos prostáticos, como resecção transuretral ou biópsia transretal guiada por ultra-sonografia, são simples, eficazes e seguros com o uso de anestesia local. Esta opção pode ser factível frente à várias condições especiais, como cirurgias prostáticas simples, sendo particularmente útil no grupo de pacientes de alto risco cirúrgico, onde a anestesia inalatória ou espinhal não é aconselhável

Cosmic Evolution of Black Holes and Spheroids. IV. The BH Mass - Spheroid Luminosity Relation

From high-resolution images of 23 Seyfert-1 galaxies at z=0.36 and z=0.57 obtained with the Near Infrared Camera and Multi-Object Spectrometer on board the Hubble Space Telescope (HST), we determine host-galaxy morphology, nuclear luminosity, total host-galaxy luminosity and spheroid luminosity. Keck spectroscopy is used to estimate black hole mass (M_BH). We study the cosmic evolution of the M_BH-spheroid luminosity (L_sph) relation. In combination with our previous work, totaling 40 Seyfert-1 galaxies, the covered range in BH mass is substantially increased, allowing us to determine for the first time intrinsic scatter and correct evolutionary trends for selection effects. We re-analyze archival HST images of 19 local reverberation-mapped active galaxies to match the procedure adopted at intermediate redshift. Correcting spheroid luminosity for passive luminosity evolution and taking into account selection effects, we determine that at fixed present-day V-band spheroid luminosity, M_BH/L_sph \propto (1+z)^(2.8+/-1.2). When including a sample of 44 quasars out to z=4.5 taken from the literature, with luminosity and BH mass corrected to a self-consistent calibration, we extend the BH mass range to over two orders of magnitude, resulting in M_BH/L_sph \propto (1+z)^(1.4+/-0.2). The intrinsic scatter of the relation, assumed constant with redshift, is 0.3+/-0.1 dex (<0.6 dex at 95% CL). The evolutionary trend suggests that BH growth precedes spheroid assembly. Interestingly, the M_BH-total host-galaxy luminosity relation is apparently non-evolving. It hints at either a more fundamental relation or that the spheroid grows by a redistribution of stars. However, the high-z sample does not follow this relation, indicating that major mergers may play the dominant role in growing spheroids above z~1.Comment: 39 pages, 11 figures. Accepted for publication in the Astrophysical Journa

Three flavor oscillation analysis of atmospheric neutrinos in super-kamiokande

In this dissertation atmospheric neutrino data from the 50 kiloton water-Cherenkov detector, Super-Kamiokande, are studied in the context of neutrino oscillations. Data presented here are taken from the 1489-day SK-I and 803-day SK-II exposures. Super-Kamiokande's atmospheric neutrino sample exhibits a zenith angle dependent deficit of vmu interactions which is well explained by maximal two-flavor vmu double arrow vgamma oscillations. This analysis extends the two-flavor framework to include all active neutrino flavors and searches for sub-dominant oscillation effects in the oscillations of atmospheric neutrinos. If the last unknown mixing angle, theta13, is non-zero there is enhancement (suppression) of the vmu to ve three-flavor oscillation probability in matter for several GeV neutrinos with long baselines under the normal (inverted) mass hierarchy. At Super-Kamiokande this effect would manifest itself as an increase in the high energy ve event rate coming from below the detector. Searching the SK-I, SK-II and their combined data finds no evidence of a rate excess and yields a best fit to theta13 of zero assuming either hierarchy. This extended analysis remains consistent with the current knowledge of two-flavor atmospheric mixing finding best fit values sin2theta23 equals 0.5 and deltam2 equals 2.6x10minus3eV2. No preference for either the normal or inverted mass hierarchy is found in the data

COMPRAS PÚBLICAS COMO INSTRUMENTO DE DESENVOLVIMENTO LOCAL

Segundo estimativa do Ministério do Planejamento, Orçamento e Gestão, as compras públicas movimentam valores de aproximadamente 15% do PIB. O presente estudo pretende verificar empiricamente o impacto das compras públicas como instrumento de desenvolvimento socioeconômico nos municípios do Paraná. Por meio da utilização da regressão linear múltipla aplicada a dados referente às compras públicas dos municípios paranaenses em 2013, variáveis socioeconômicas e ao Índice IPARDES de Desempenho Municipal (IPDM), foi verificado o efeito das compras públicas no processo de desenvolvimento no Estado do Paraná. O modelo estimado demonstra que as compras públicas, quando realizadas em fornecedores locais, implicaram em um maior IPDM nos municípios paranaenses. Apesar do modelo demonstrar uma relação positiva entre a realização de compras públicas em fornecedores locais e o IPDM, verifica-se que o impacto das compras públicas no IPDM é de pequena proporção. Desta forma, a utilização das compras públicas como fator estratégico para desenvolvimento socioeconômico apresenta suas limitações.  A utilização das compras públicas como indutor do desenvolvimento local necessita de um maior debate e da adequação da legislação vigente referente ao processo de licitaçã

Uncoupling, metabolic inhibition and induction of mitochondrial permeability transition in rat liver mitochondria caused by the major long-chain hydroxyl monocarboxylic fatty acids accumulating in LCHAD deficiency

AbstractPatients with long-chain 3-hydroxy-acyl-CoA dehydrogenase (LCHAD) deficiency commonly present liver dysfunction whose pathogenesis is unknown. We studied the effects of long-chain 3-hydroxylated fatty acids (LCHFA) that accumulate in LCHAD deficiency on liver bioenergetics using mitochondrial preparations from young rats. We provide strong evidence that 3-hydroxytetradecanoic (3HTA) and 3-hydroxypalmitic (3HPA) acids, the monocarboxylic acids that are found at the highest tissue concentrations in this disorder, act as metabolic inhibitors and uncouplers of oxidative phosphorylation. These conclusions are based on the findings that these fatty acids decreased ADP-stimulated (state 3) and uncoupled respiration, mitochondrial membrane potential and NAD(P)H content, and, in contrast, increased resting (state 4) respiration. We also verified that 3HTA and 3HPA markedly reduced Ca2+ retention capacity and induced swelling in Ca2+-loaded mitochondria. These effects were mediated by mitochondrial permeability transition (MPT) induction since they were totally prevented by the classical MPT inhibitors cyclosporin A and ADP, as well as by ruthenium red, a Ca2+ uptake blocker. Taken together, our data demonstrate that the major monocarboxylic LCHFA accumulating in LCHAD deficiency disrupt energy mitochondrial homeostasis in the liver. It is proposed that this pathomechanism may explain at least in part the hepatic alterations characteristic of the affected patients

Crescimento e teor foliar de nutrientes em cafeeiro decorrente da omissão isolada e simultânea de Ca, B, Cu e Zn

Realized in greenhouse, the present research aimed to evaluate the effect of isolated and simultaneous omission of Ca, B, Cu and Zn on growth, leaf nutrient concentration level, as well as the manifestation of deficiency visual symptoms from coffee plants (Coffea arabica L.). The experimental design was fully randomized with four replicates and eight treatments, as mentioned above: complete nutritive solution (Hoagland &amp; Arnon, 1950), solution with individual omission of Ca, B, Cu and Zn and double omission simultaneous of Ca and B, Cu and Zn and B and Zn. The omission of nutrient in the nutritive solution caused a reduction in leaf concentration, independent to be isolated or associated with another. The leaf analysis showed in the treatments with nutrient omission, independent of omitted nutrient, the leaf level of Ca (2,02 g/kg), B (14,98 mg/kg), Cu (0,91 mg/kg) and Zn (3,15 mg/kg), was always lower than the verified for plants with full treatments. The isolated and simultaneous absence reduced the plant development, causing morphological modifications with characteristics symptoms of deficiency. The simultaneous symptoms of deficiency were initially characteristic for leaf nutrient. The reduction in total dry matter of coffee was influenced in the following order: B = Ca e B = B e Zn &gt; Zn = Cu = Cu e Zn &gt; Ca.Conduzido em casa-de-vegetação, com o presente trabalho objetivou-se avaliar o efeito da omissão isolada e simultânea de Ca, B, Cu e Zn no crescimento, na concentração foliar de nutrientes, bem como na manifestação de sintomas visuais de deficiência em plantas de cafeeiro (Coffea arabica L.). O delineamento experimental utilizado foi o inteiramente casualizado, com quatro repetições e oito tratamentos, sendo: solução nutritiva completa (Hoagland &amp; Arnon, 1950), solução com omissão individual de B, Cu e Zn e omissão dupla simultânea de B e Ca, de B e Zn e de Cu e Zn. A omissão dos nutrientes na solução nutritiva promoveu redução de sua concentração nas folhas, independentemente de estar isolado ou associado a outro. Pela análise foliar, verificou-se que, nos tratamentos com omissão de nutrientes, independentemente do nutriente omitido, os teores médios de Ca (2,02 g/kg), B (14,98 mg/kg), Cu (0,91 mg/kg) e Zn (3,15 mg/kg) foram sempre inferiores aos verificados nas plantas do tratamento completo e insuficientes para o crescimento das mudas. A ausência isolada ou simultânea comprometeu o desenvolvimento das plantas, levando a modificações morfológicas com sintomas característicos de deficiência. Os sintomas simultâneos de deficiência foram, inicialmente, característicos de cada elemento. A redução na matéria seca total das plantas de cafeeiro foi influenciada na seguinte ordem: B = Ca e B = B e Zn &gt; Zn = Cu = Cu e Zn &gt; Ca