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Composição terpénica e actividade anti-oxidante de plantas e infusões

Santos, Magda Raquel Mota dos
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
Português
Relevância na Pesquisa
17.44%
Para este estudo foram seleccionadas 25 espécies de plantas, que normalmente são utilizadas pela população Portuguesa para a preparação de infusões. Com vista à sua valorização, procurando em especial compostos/extractos com potenciais efeitos benéficos para a saúde, estas foram estudadas relativamente à sua composição em compostos terpénicos (C10 e C15) e actividade anti-oxidante. A composição terpénica das plantas e respectivas infusões foi estudada por recurso à técnica de micro-extracção em fase sólida, combinada com a cromatografia em fase gasosa com detecção por espectrometria de massa com quadrupolo (HS-SPME/GC-qMS). De forma a avaliar a actividade anti-oxidante utilizou-se o método do DPPH•. Com vista a optimizar a eficiência extractiva relativamente aos compostos terpénicos em C10 e C15, foram testados três tipos de revestimento de fibras de SPME (PA, DVB/CAR/PDMS e PDMS). Verificou-se que o DVB/CAR/PDMS foi o revestimento que apresentou uma maior área cromatográfica e um maior número de compostos identificados, com a excepção dos sesquiterpenos oxigenados. Como os sesquiterpenos oxigenados são componentes minoritários das amostras estudadas, conclui-se que o DVB/CAR/PDMS apresenta uma maior eficiência extractiva relativamente aos analitos de interesse. Com recurso à análise multivariada foram estudadas as fontes de variabilidade relativamente aos compostos terpénicos das plantas secas e das respectivas infusões. Verificou-se a formação de grupos relacionados essencialmente com os compostos maioritários de cada espécie. Desta forma...

Composição terpénica e actividade antioxidante de plantas e óleos

Tavares, Ângela Paula Martinho
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
Português
Relevância na Pesquisa
17.63%
Os efeitos benéficos para a saúde humana associados ao uso de plantas, assim como dos seus óleos essenciais ou extractos, têm sido reconhecidos desde a antiguidade. Actualmente tem-se verificado um interesse crescente em conhecer quais os compostos responsáveis por esses efeitos. O interesse pelos compostos bioactivos das plantas tem crescido devido à ideia, generalizada, de que os produtos naturais apresentam menor toxicidade e efeitos colaterais relativamente aos produtos de síntese. Estes efeitos benéficos para a saúde podem ser explicados por um ou vários constituintes das plantas, entre estes destacam-se alguns metabolitos secundários, como os compostos terpénicos em C10 e C15. A actividade antioxidante é um dos efeitos muito explorado nos estudos sobre produtos naturais, dado que actualmente se tem dado muita importância aos antioxidantes naturais presentes em fontes vegetais devido ao seu suposto papel na protecção do corpo humano contra um grande número de doenças degenerativas. Esta actividade é o resultado da presença e/ou interacção entre vários constituintes das plantas. Compostos fenólicos, carotenóides, compostos terpénicos, entre outros, podem estar na base da actividade antioxidante associada às plantas. Com vista a uma futura valorização das plantas como possíveis fontes de compostos bioactivos...

Critical role of anteiso-C15:0 fatty acid in the growth of Listeria monocytogenes at low temperatures.

Annous, B A; Becker, L A; Bayles, D O; Labeda, D P; Wilkinson, B J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1997 Português
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Listeria monocytogenes is a food-borne pathogen capable of growth at refrigeration temperatures. Membrane lipid fatty acids are major determinants of a sufficiently fluid membrane state to allow growth at low temperatures. L. monocytogenes was characterized by a fatty acid profile dominated to an unusual extent (> 95%) by branched-chain fatty acids, with the major fatty acids being anteiso-C15:0, anteiso-C17:0, and iso-C15:0 in cultures grown in complex or defined media at 37 degrees C. Determination of the fatty acid composition of L. monocytogenes 10403S and SLCC 53 grown over the temperature range 45 to 5 degrees C revealed two modes of adaptation of fatty acid composition to lower growth temperatures: (i) shortening of fatty acid chain length and (ii) alteration of branching from iso to anteiso. Two transposon Tn917-induced cold-sensitive mutants incapable of growth at low temperatures had dramatically altered fatty acid compositions with low levels of i-C15:0, a-C15:0, and a-C17:0 and high levels of i-C14:0, C14:0, i-C16:0, and C16:0. The levels of a-C15:0 and a-C17:0 and the ability to grow at low temperatures were restored by supplementing media with 2-methylbutyric acid, presumably because it acted as a precursor of methylbutyryl coenzyme A...

Identification of the heat-inducible protein C15.4 as the groES gene product in Escherichia coli.

Tilly, K; VanBogelen, R A; Georgopoulos, C; Neidhardt, F C
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1983 Português
Relevância na Pesquisa
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The product of the Escherichia coli morphogenetic gene groES (mopB) was identified as the heat-inducible protein C15.4 by two-dimensional gel analysis of the products of wild-type and mutant alleles carried on the bacterial chromosome, on a hybrid plasmid, and on a transducing phage.

Effect of Temperature on the Fatty Acid Composition of Thermus aquaticus

Ray, Paul H.; White, David C.; Brock, Thomas D.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1971 Português
Relevância na Pesquisa
17.44%
Thermus aquaticus contains four major fatty acids, iso-C15 (28%), iso-C16 (9%), normal-C16 (13%), and iso-C17 (48%), when grown at 70 C, as determined by gas chromatography and mass spectrometry. Small amounts of iso-C12, normal-C12:1, iso-C13, normal-C14, iso-C14, and normal-C15:1 were also detected. A change in growth temperature (50 to 75 C at 5-C intervals) affects a shift in the proportions of some of the fatty acids. The proportions of the monoenoic and branched-C17 fatty acids decreased and the proportions of the higher-melting iso-C16 and normal-C16 fatty acids increased. Cells grown at 75 C contained 70% more total fatty acids than cells grown at 50 C. The largest increases, in absolute amounts, were in the content of iso-C16 and normal-C16 fatty acids, with only a 1.6-fold increase in the major iso-C15 and iso-C17 fatty acids. There was a 2.5-fold decrease in normal-C15:1 and at least a 24-fold decrease in anteiso-C17, which is present at 50 and 55 C but not at higher temperatures. There was no difference in proportion or amount of fatty acids between exponential and stationary-phase cells grown at 70 C. When cells were grown on glutamate instead of yeast-extract and tryptone at 70 C, the total fatty acid content remained constant...

Cultural Characteristics and Fatty Acid Composition of Propionibacteria

Moss, C. Wayne; Dowell, V. R.; Farshtchi, D.; Raines, L. J.; Cherry, W. B.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /02/1969 Português
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The cultural characteristics and cellular fatty acid composition of 40 strains representing 7 species of Propionibacterium and of 9 cultures of anaerobic corynebacteria were studied. The cultures were characterized by means of 23 separate cultural and biochemical tests. Cultures of the two genera differed consistently in only two reactions; the propionibacteria did not produce indole or liquefy gelatin, whereas the anaerobic corynebacteria were consistently positive with these tests. The fatty acids were extracted from whole cells and examined as methyl esters by gas-liquid chromatography. The most abundant acid in the seven Propionibacterium species was a C15-saturated branched-chain acid which was present in both the iso-and anteiso-form. Based on a comparison of the relative abundance of these isomers (i-C15 and a-C15), the species were separated into two groups. P. freudenreichii and P. shermanii (group one) were similar and contained the a-C15 isomer as the predominant acid. The i-C15 isomer was the most abundant acid in the second group (P. arabinosum, P. jensenii, P. pentosaceum, P. thoenii, and P. zeae). The fatty acid profiles of the anaerobic corynebacteria were somewhat similar to those of the second group of propionibacteria...

Fatty Acids in the Genus Bacillus I. Iso- and Anteiso-Fatty Acids as Characteristic Constituents of Lipids in 10 Species1

Kaneda, Toshi
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/1967 Português
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Fatty acids produced by 22 strains of 10 species of the genus Bacillus were analyzed on a very efficient and selective gas-liquid chromatographic column. All of the 10 species, alvei, brevis, cereus, circulans, licheniformis, macerans, megaterium, polymyxa, pumilus, and subtilis, produced eight fatty acids, six branched (anteiso-C15, anteiso-C17, iso-C14, iso-C15, iso-C16, and iso-C17) and two normal (n-C14 and n-C16). In all cases, the six branched-chain fatty acids made up over 60% of the total fatty acids. In addition to the eight fatty acids, B. cereus produced four extra fatty acids, three branched (anteiso-C13, iso-C12, and iso-C13) and one monoenoic-n-C16. Furthermore, there were distinct differences in the relative amounts of fatty acids produced between B. cereus and the remaining nine species. B. cereus produced iso-C15 fatty acid in the largest amount on a glucose-yeast extract medium as well as on Pennassay Broth. On the other hand, for the remaining nine species, anteiso-C15 fatty acid was the major fatty acid from the glucose-yeast extract medium, whereas the amount of iso-C15 fatty acid from Penassay Broth became comparable to that of anteiso-C15 fatty acid. Mechanisms and various factors affecting the fatty acid distribution pattern in the 10 Bacillus species are discussed.

Binding of Clostridium botulinum type C neurotoxin to different neuroblastoma cell lines.

Yokosawa, N; Kurokawa, Y; Tsuzuki, K; Syuto, B; Fujii, N; Kimura, K; Oguma, K
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1989 Português
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Binding of type C neurotoxin (C1 toxin) from Clostridium botulinum (strain Stockholm) to neuroblastoma cell lines was studied by using biotinylated anti-toxin antibody and avidin-biotinylated peroxidase complex. The neurotoxin bound with high efficiency to mouse neuroblastoma (NS-20Y and NIE-115) cells and to hybridomas of rat glioblastoma and mouse neuroblastoma (NG108-C15) cells. The toxin bound little to human neuroblastoma, rat astrocytoma, and nonneural cell lines. Binding of the neurotoxin to NG108-C15 cells was inhibited by gangliosides (GT1b and GM1) and by monoclonal antibodies (CA-12 and C-9), although inhibition was not complete. Sequential preincubation of C1 toxin with GT1b and CA-12 caused complete inhibition. A Scatchard plot of binding of 125I-labeled C1 toxin to NG108-C15 cells showed a hyperbolic curve. Monoclonal antibody CA-12 but not C-9 neutralized the lethal activity of the toxin toward mice. Only C-9 clearly inhibited toxin binding to GT1b. These results suggest that NG108-C15 cells have at least two kinds of receptors for C1 toxin. From the results of binding tests with neuraminidase-, pronase-, and trypsin-treated NG108-C15 cells, the chemical nature of the high-affinity site was presumed to be a glycoprotein containing sialic acid. GT1b may have an important role in low-affinity sites.

Are C14-C15 single bond isomerizations of the retinal chromophore involved in the proton-pumping mechanism of bacteriorhodopsin?

Smith, S O; Hornung, I; van der Steen, R; Pardoen, J A; Braiman, M S; Lugtenburg, J; Mathies, R A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /02/1986 Português
Relevância na Pesquisa
27.59%
Resonance Raman spectroscopy is used to examine the possibility that C14-C15 single bond isomerizations of the retinal prosthetic group are involved in the photochemical reactions of bacteriorhodopsin. Normal mode calculations show that the vibration that contains predominantly C14-C15 stretch character is approximately equal to 70 cm-1 lower in frequency in the 14-s-cis conformer than in the s-trans case. This geometric effect is insensitive to out-of-plane twists and should be observed in the sterically hindered 13-cis, 14-s-cis retinal protonated Schiff base, which has been proposed as the chromophore in the K and L intermediates of bacteriorhodopsin. Resonance Raman spectra were obtained of K625 by using the low temperature (77 K) spinning-cell technique. Isotopic substitutions with 13C and 2H show that significant C14-C15 stretch character is observed in normal modes at approximately equal to 1185-1195 cm-1. The relatively high frequency of the C14-C15 stretch argues that K625 contains a 13-cis, 14-s-trans chromophore. Similarly, isotopic derivatives show that L550 has a localized C14-C15 stretch at 1172 cm-1, consistent with a 14-s-trans chromophore. These results argue that the primary step in bacteriorhodopsin is a C13=C14 trans----cis photoisomerization that does not involve C14-C15 s-cis structures.

Determination of retinal Schiff base configuration in bacteriorhodopsin

Smith, Steven O.; Myers, Anne B.; Pardoen, Johannes A.; Winkel, Chris; Mulder, Patrick P. J.; Lugtenburg, Johan; Mathies, Richard
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1984 Português
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Resonance Raman spectra of the BR568, BR548, K625, and L550 intermediates of the bacteriorhodopsin photocycle have been obtained in 1H2O and 2H2O by using native purple membrane as well as purple membrane regenerated with 14,15-13C2 and 12,14-2H2 isotopic derivatives of retinal. These derivatives were selected to determine the contribution of the C14—C15 stretch to the normal modes in the 1100- to 1400-cm-1 fingerprint region and to characterize the coupling of the C14—C15 stretch with the NH rock. Normal mode calculations demonstrate that when the retinal Schiff base is in the C[unk]N cis configuration the C14—C15 stretch and the NH rock are strongly coupled, resulting in a large (≈50-cm-1) upshift of the C14—C15 stretch upon deuteration of the Schiff base nitrogen. In the C[unk]N trans geometry these vibrations are weakly coupled and only a slight (<5-cm-1) upshift of the C14—C15 stretch is predicted upon N-deuteration. In BR568, the insensitivity of the 1201-cm-1 C14—C15 stretch to N-deuteration demonstrates that its retinal C[unk]N configuration is trans. The C14—C15 stretch in BR548, however, shifts up from 1167 cm-1 in 1H2O to 1208 cm-1 in 2H2O, indicating that BR548 contains a C[unk]N cis chromophore. Thus, the conversion of BR568 to BR548 (dark adaptation) involves isomerization about the C[unk]N bond in addition to isomerization about the C13[unk]C14 bond. The insensitivity of the native...

Exogenous Isoleucine and Fatty Acid Shortening Ensure the High Content of Anteiso-C15:0 Fatty Acid Required for Low-Temperature Growth of Listeria monocytogenes

Zhu, Kun; Ding, Xiang; Julotok, Mudcharee; Wilkinson, Brian J.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /12/2005 Português
Relevância na Pesquisa
27.44%
Previous studies have demonstrated that the branched-chain fatty acid anteiso-C15:0 plays a critical role in the growth of Listeria monocytogenes at low temperatures by ensuring sufficient membrane fluidity. Studies utilizing a chemically defined minimal medium revealed that the anteiso fatty acid precursor isoleucine largely determined the fatty acid profile and fatty acid response of the organism to lowered growth temperature. When isoleucine was sufficient, the fatty acid profile was very uniform, with anteiso fatty acids comprising up to 95% of total fatty acid, and the major fatty acid adjustment to low temperature was fatty acid chain shortening, which resulted in an increase of anteiso-C15:0 solely at the expense of anteiso-C17:0. When isoleucine was not supplied, the fatty acid profile became more complex and was readily modified by leucine, which resulted in a significant increase of corresponding iso fatty acids and an inability to grow at 10°C. Under this condition, the increase of anteiso-C15:0 at low temperature resulted from the combined effect of increasing the anteiso:iso ratio and chain shortening. A branched-chain α-keto acid dehydrogenase-defective strain largely lost the ability to increase the anteiso:iso ratio. Cerulenin...

The c15 ring of the Spirulina platensis F-ATP synthase: F1/F0 symmetry mismatch is not obligatory

Pogoryelov, Denys; Yu, Jinshu; Meier, Thomas; Vonck, Janet; Dimroth, Peter; Muller, Daniel J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
26.89%
The oligomeric c ring of the F-ATP synthase from the alkaliphilic cyanobacterium Spirulina platensis was isolated and characterized. Mass spectroscopy analysis indicated a mass of 8,210 Da, reflecting that of a c monomer. The mass increased by 206 Da after treatment with the c-subunit-specific inhibitor dicyclohexylcarbodiimide (DCCD), which indicated modification of the ion-binding carboxylate by DCCD. Atomic force microscopy topographs of c rings from S. platensis showed 15 symmetrically assembled subunits. The c15-mer reported here is the largest c ring that is isolated and does not show the classical c-ring mismatch to the three-fold symmetry of the F1 domain.

Anti-idiotype antibody induced cellular immunity in mice transgenic for human carcinoembryonic antigen

Saha, Asim; Chatterjee, Sunil K; Foon, Kenneth A; Bhattacharya-Chatterjee, Malaya
Fonte: Blackwell Science Inc Publicador: Blackwell Science Inc
Tipo: Artigo de Revista Científica
Publicado em /08/2006 Português
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17.52%
In the present study, we have analysed the detailed cellular immune mechanisms involved in tumour rejection in carcinoembryonic antigen (CEA) transgenic mice after immunization with dendritic cells (DC) pulsed with an anti-idiotype (Id) antibody, 3H1, which mimics CEA. 3H1-pulsed DC vaccinations resulted in induction of CEA specific cytotoxic T lymphocyte (CTL) responses in vitro and the rejection of CEA-transfected MC-38 murine colon carcinoma cells, C15, in vivo (Saha et al.,Cancer Res 2004; 64: 4995–5003). These CTL mediated major histocompatibility complex (MHC) class I-restricted tumour cell lysis, production of interferon-γ (IFN-γ) and tumour necrosis factor-α (TNF-α), and expression of Fas ligand (FasL) and TNF-related apoptosis-inducing ligand (TRAIL) in response to C15 cells. CTL used perforin-, FasL-, and TRAIL-mediated death pathways to lyse C15 cells, although perforin-mediated killing was the predominant lytic mechanism in vitro. The cytokines IFN-γ and TNF-α synergistically enhanced surface expression of Fas, TRAIL receptor, MHC class I and class II on C15 cells that increased the sensitivity of tumour cells to CTL lysis. CTL activity generated in 3H1-pulsed DC immunized mice was directed against an epitope defined by the idio-peptide LCD-2...

Mutational Analysis of Active Site Residues Essential for Sensing of Organic Hydroperoxides by Bacillus subtilis OhrR▿

Soonsanga, Sumarin; Fuangthong, Mayuree; Helmann, John D.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Português
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17.44%
Bacillus subtilis OhrR is the prototype for the one-Cys family of organic peroxide-sensing regulatory proteins. Mutational analyses indicate that the high sensitivity of the active site cysteine (C15) to peroxidation requires three Tyr residues. Y29 and Y40 from the opposing subunit of the functional dimer hydrogen bond with the reactive Cys thiolate, and substitutions at these positions reduce or eliminate the ability of OhrR to respond to organic peroxides. Y19 is also critical for peroxide sensing, and the Ala substitution mutant (OhrR Y19A) is less susceptible to oxidation at the active site C15 in vivo. The Y19A protein also displays decreased sensitivity to peroxide-mediated oxidation in vitro. Y19 is in van der Waals contact with two residues critical for protein function, F16 and R23. The latter residue makes critical contact with the DNA backbone in the OhrR-operator complex. These results indicate that the high sensitivity of the OhrR C15 residue to oxidation requires interactions with the opposed Tyr residues. Oxidative modification of C15 likely disrupts the C15-Y29′-Y40′ hydrogen bond network and thereby initiates conformational changes that reduce the ability of OhrR to bind to its operator site.

A Multifaceted Phosphate Tether: Application to the C15-C30 Subunit of Dolabelides A-D

Whitehead, Alan; Waetzig, Joshua D.; Thomas, Christopher D.; Hanson, Paul R.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
26.89%
Construction of the C15-C30 subunit of dolabelide utilizing a temporary phosphate tether is described. Two routes are reported that make use of the orthogonal protecting- and leaving-group properties innate to phosphate esters. One route relies on a selective terminal oxidation, while a second utilizes a CM/selective hydrogenation sequence. Both routes depend on a highly regio- and diastereoselective cuprate addition to set the requisite stereochemistry at C22.

A synthesis of the C1-C15 domain of the halichondrins

Jackson, Katrina L.; Henderson, James A.; Morris, Jonathan C.; Motoyoshi, Hajime; Phillips, Andrew J.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/04/2008 Português
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A concise route to the C1–C15 domain of the halichondrins is described. The key reaction is the conversion of a furfuryl alcohol to a pyranone. The stereocenter of this pyranone serves as the starting point for the other 8 stereocenters.

Coordination of distinct motor structures through remote axonal coupling of projection interneurons

Jing, Jian; Sasaki, Kosei; Perkins, Matthew H; Siniscalchi, Michael J; Ludwar, Bjoern C; Cropper, Elizabeth C; Weiss, Klaudiusz R
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 26/10/2011 Português
Relevância na Pesquisa
17.44%
Complex behaviors often require coordinated movements of dissimilar motor structures. The underlying neural mechanisms are poorly understood. We investigated cycle-by-cycle coordination of two dissimilar feeding structures in Aplysia californica: the external lips and the internal radula. During feeding, the lips open while the radula protracts. Lip and radula motoneurons are located in the cerebral and buccal ganglia respectively, and radula motoneurons are controlled by a well-characterized buccal central pattern generator (CPG). Here, we examined whether the three electrically-coupled lip motoneurons C15/16/17 are controlled by the buccal CPG or by a previously-postulated cerebral CPG. Two buccal-cerebral projection interneurons, B34 and B63, which are part of the buccal CPG and mediate radula protraction, monosynaptically excite C15/16/17. Recordings from the B34 axon in the cerebral ganglion demonstrate its direct electrical coupling with C15/16/17, eliminating the need for a cerebral CPG. Moreover, when the multifunctional buccal CPG generates multiple forms of motor programs due to the activation of two inputs: the command-like neuron CBI-2 and the esophageal nerve (EN), C15/16 exhibit activity patterns that are distinct from C17. These distinct activity patterns result from combined activity of B34 and B63 and their differential excitation of C15/16 vs. C17. In more general terms...

Bacteriorhodopsin's L550 intermediate contains a C14-C15 s-trans-retinal chromophore.

Fodor, S P; Pollard, W T; Gebhard, R; van den Berg, E M; Lugtenburg, J; Mathies, R A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1988 Português
Relevância na Pesquisa
27.44%
Conformational changes of the retinal chromophore about the C14-C15 bond in bacteriorhodopsin (BR) have been proposed in models for the mechanism of light-driven proton transport. To determine the C14-C15 conformation in BR's L550 intermediate, we have examined the resonance Raman spectra of BR derivatives regenerated with retinal deuterated at the 14 and 15 positions. Vibrational calculations show that the C14-2H and C15-2H rocking modes form symmetric (A) and antisymmetric (B) combinations in [14,15-2H]retinal chromophores. When there is a trans conformation about the single bond between C14 and C15 (14-s-trans), a small frequency separation or splitting is observed between the A and B modes, which are found at approximately equal to 970 cm-1. In 14-s-cis molecules, the splitting is large, and the Raman-active symmetric A mode is predicted at approximately equal to 850 cm-1. In addition, the monodeuterium rock should appear at an unusually low frequency (920-930 cm-1) in the 14-2H-labeled 14-s-cis molecules. These patterns are insensitive to computational details: similar results are predicted by a modified Urey-Bradley force field and by MNDO (modified neglect of differential overlap) calculations for twisted chromophores and for highly delocalized protonated Schiff base cations. Time-resolved resonance Raman spectra were obtained of BR's L550 intermediate regenerated with [14-2H]-...

Novel transcription from the Epstein-Barr virus terminal EcoRI fragment, DIJhet, in a nasopharyngeal carcinoma.

Gilligan, K; Sato, H; Rajadurai, P; Busson, P; Young, L; Rickinson, A; Tursz, T; Raab-Traub, N
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1990 Português
Relevância na Pesquisa
17.67%
Transcription of Epstein-Barr virus (EBV) genes in epithelial tissue, one of the two principal cell types infected by EBV, is not well characterized. EBV transcription in a nasopharyngeal carcinoma established in nude mice, C15, has been analyzed by using strand-specific RNA probes and sequence analysis of a C15 cDNA library. In C15, two equally abundant mRNAs of 3.7 and 2.8 kilobases (kb) are encoded by the sequences that encode latent membrane protein (LMP). Hybridization with probes specific for the 3' end of the LMP mRNA to Northern (RNA) blots and sequence analysis of cDNAs representing the messages indicated that the 3.7- and 2.8-kb mRNAs are 3' coterminal. Sequence analysis of additional cDNAs revealed an mRNA that is spliced identically to the LMP mRNA but is initiated 5' to the promoter for LMP. A probe representing the sequences contained within the cDNA which are 5' to the LMP promoter identified the 3.7-kb mRNA in C15 and a low-abundance 3.7-kb mRNA in B95-8 RNA. These data indicate that transcription of the LMP-encoding sequences is complex and that LMP can be expressed from an additional RNA in both nasopharyngeal carcinoma and lymphoid cells. Hybridization with BamHI-A identified a predominant 4.8-kb mRNA and two less abundant larger-molecular-weight mRNAs transcribed in C15. These mRNAs are consistently expressed in all passages in nude mice of the C15 tumor. Hybridization with strand-specific probes and sequence analysis of three cDNAs revealed that these mRNAs are transcribed from left to right. Sequence analysis of cDNAs representing the 3' end of the mRNAs identified an open reading frame that could potentially encode a protein of 174 amino acids. In situ hybridization of a 35S-labeled RNA probe homologous to the BamHI-A cDNA to tissue sections revealed that the BamHI-A mRNA is not focally expressed and is transcribed in all cells within the C15 tumor. Linear forms of EBV DNA were not detected in any of the C15 tumors...

Evaluación y mejora de la calidad en la alimentación hospitalaria

Gómez Sánchez, María Bienvenida
Fonte: Universidade de Múrcia Publicador: Universidade de Múrcia
Tipo: Tese de Doutorado Formato: application/pdf
Português
Relevância na Pesquisa
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Objetivos: Evaluar la calidad de todo el proceso de alimentación hospitalaria, desde la recepción de la materia prima hasta la ingesta de los alimentos por los pacientes. Identificar y diseñar medidas correctoras encaminadas a evitar los errores más frecuentes. Material y método: Se realizó un estudio de evaluación y mejora de la calidad pre/postintervención con medidas repetidas durante 1 año. El estudio se desarrolló en 4 fases. En la primera fase se realizó la evaluación semanal del cumplimiento de una serie de criterios de calidad que fueron: transporte de las materias primas (C1), almacenamiento en las cámaras frigoríficas de productos lácteos (C2), de frutas y verduras (C3), de productos cárnicos (C4), de pescados (C5), de productos elaborados (C6), de productos congelados (C7) y de alimentos no perecederos (C8). Se supervisó la calidad de los alimentos no perecederos (C9), perecederos refrigerados (C10) y congelados (C11). También se evaluó el cumplimiento de la petición de dietas (C12), el horario de petición de dietas (C13), que las bandejas de alimentación de los pacientes correspondieran a la pauta del médico (C14), que estas estuviesen completas con todos sus complementos alimenticios (C15), la presentación de la comida (C16) y el horario de entrega de la comida al paciente (C17). Así mismo...