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21.
Duarte ME Cauduro JP Noseda DG Noseda MD Gonçalves AG Pujol CA Damonte EB Cerezo AS 《Carbohydrate research》2004,339(2):335-347
The sulfated agaran isolated by water extraction from the red seaweed, Acanthophora spicifera (Rhodomelaceae, Ceramiales), is made up of A-units highly substituted with sulfate groups on C-2 (28-30%), sulfates on C-2 and 4,6-O-(1'-carboxyethylidene) groups (9-15%), and only the C-2 sulfate groups (5-8%) with small amounts of C-6 sulfate, 6-O-methyl, and nonsubstituted residues. B-units are formed mainly by 3,6-anhydro-alpha-L-galactose (15-16%) and its precursor, alpha-L-galactose 6-sulfate (10-17%), together with lesser amounts of 3,6-anhydro-alpha-L-galactose 2-sulfate, alpha-L-galactose 2,6-disulfate, alpha-L-galactose 2,3,6-tri-sulfate, alpha-L-galactose 2,6-disulfate 3-xylose, 2-O-methyl-alpha-L-galactose, and unsubstituted alpha-L-galactose. Small, but significant quantities of beta-D-xylose were found in all the fractions, together with small amounts to traces of D-glucose. Some of the fractions have high antiviral activity. Attempts to correlate structure and antiviral activity in agarans are presented. 相似文献
22.
M.Kaniz Fatema Diogo R.B. Ducatti M. Eug?nia R. Duarte Alberto S. Cerezo María C. Matulewicz 《Carbohydrate research》2010,345(2):275-2314
MALDI-TOF mass spectrometry analyses of several oligosaccharides (aldoses) and oligosaccharide alditols derived from agaroses, kappa- and iota-carrageenans using different matrices (2,5-dihydroxybenzoic acid, nor-harmane, ferulic acid, and the ionic liquid matrices 2,5-dihydroxybenzoic acid-n-butylamine and ferulic acid-n-butylamine) were conducted. These carbohydrates were selected as model compounds to study the MALDI prompt and post-source decay (PSD) fragmentation processes of both families of oligosaccharides. Sulfated alditols showed in the negative-ion mode the molecular ion as [M−Na]− together with the species yielded by their prompt fragmentation (mainly desulfation) while the sulfated oligosaccharides (aldoses) showed mainly glycosidic prompt fragmentation (glycosidic C-cleavages and desulfation). Non-sulfated aldoses and alditols, which could only be analyzed in positive-ion mode ([M+Na]+), did not suffer any prompt fragmentation. The former yielded cross-ring fragmentation in the PSD mode. Best results were obtained by using 2,5-dihydroxybenzoic acid and/or nor-harmane as matrices for all the compounds studied. 相似文献
23.
Garibay RI Aguilera-Arreola MG Ocañia AN Cerezo SG Mendoza MS López JM Campos CE Cravioto A Castro-Escarpulli G 《Memórias do Instituto Oswaldo Cruz》2006,101(2):157-161
A total of 221 strains of Aeromonas species isolated in Mexico from clinical (161), environmental (40), and food (20) samples were identified using the automated system bioMérieux-Vitek. Antisera for serogroups O1 to 044 were tested using the Shimada and Sakazaki scheme. The K1 antigen was examined using as antiserum the O7:K1C of Escherichia coli. Besides, we studied the antimicrobial patterns according to Vitek AutoMicrobic system. Among the 161 clinical strains 60% were identified as A. hydrophila, 20.4% as A. caviae, and 19.25% as A. veronii biovar sobria. Only A. hydrophila and A. veronii biovar sobria were found in food (55 and 90% respectively) and environmental sources (45 and 10% respectively). Using "O" antisera, only 42.5% (94/221) of the strains were serologically identified, 55% (121/221) were non-typable, and 2.5% (6/221) were rough strains. Twenty-two different serogroups were found, O14, O16, O19, O22, and O34 represented 60% of the serotyped strains. More than 50% of Aeromonas strain examined (112/221) expressed K1 encapsulating antigen; this characteristic was predominant among Aeromonas strains of clinical origin. Resistance to ampicillin/sulbactam and cephazolin was detected in 100 and 67% of Aeromonas strain tested for their susceptibility to antibiotics. In conclusion, antibiotic-resistant Aeromonas species that possess the K1 encapsulating antigen and represent serogroups associated with clinical syndrome in man are not uncommon among Aeromonas strains isolated from clinical, food and environmental sources in Mexico. 相似文献
24.
Background
There have been many algorithms and software programs implemented for the inference of multiple sequence alignments of protein and DNA sequences. The "true" alignment is usually unknown due to the incomplete knowledge of the evolutionary history of the sequences, making it difficult to gauge the relative accuracy of the programs. 相似文献25.
On single and multiple models of protein families for the detection of remote sequence relationships
Background
The detection of relationships between a protein sequence of unknown function and a sequence whose function has been characterised enables the transfer of functional annotation. However in many cases these relationships can not be identified easily from direct comparison of the two sequences. Methods which compare sequence profiles have been shown to improve the detection of these remote sequence relationships. However, the best method for building a profile of a known set of sequences has not been established. Here we examine how the type of profile built affects its performance, both in detecting remote homologs and in the resulting alignment accuracy. In particular, we consider whether it is better to model a protein superfamily using a single structure-based alignment that is representative of all known cases of the superfamily, or to use multiple sequence-based profiles each representing an individual member of the superfamily. 相似文献26.
Camañes G Pastor V Cerezo M García-Andrade J Vicedo B García-Agustín P Flors V 《Plant physiology》2012,158(2):1054-1066
For an efficient defense response against pathogens, plants must coordinate rapid genetic reprogramming to produce an incompatible interaction. Nitrate Trasnporter2 (NRT2) gene family members are sentinels of nitrate availability. In this study, we present an additional role for NRT2.1 linked to plant resistance against pathogens. This gene antagonizes the priming of plant defenses against the bacterial pathogen Pseudomonas syringae pv tomato DC3000 (Pst). The nrt2 mutant (which is deficient in two genes, NRT2.1 and NRT2.2) displays reduced susceptibility to this bacterium. We demonstrate that modifying environmental conditions that stimulate the derepression of the NRT2.1 gene influences resistance to Pst independently of the total level of endogenous nitrogen. Additionally, hormonal homeostasis seemed to be affected in nrt2, which displays priming of salicylic acid signaling and concomitant irregular functioning of the jasmonic acid and abscisic acid pathways upon infection. Effector-triggered susceptibility and hormonal perturbation by the bacterium seem to be altered in nrt2, probably due to reduced sensitivity to the bacterial phytotoxin coronatine. The main genetic and metabolic targets of coronatine in Arabidopsis (Arabidopsis thaliana) remain largely unstimulated in nrt2 mutants. In addition, a P. syringae strain defective in coronatine synthesis showed the same virulence toward nrt2 as the coronatine-producing strain. Taken together, the reduced susceptibility of nrt2 mutants seems to be a combination of priming of salicylic acid-dependent defenses and reduced sensitivity to the bacterial effector coronatine. These results suggest additional functions for NRT2.1 that may influence plant disease resistance by down-regulating biotic stress defense mechanisms and favoring abiotic stress responses. 相似文献
27.
JOSÉ ANTONIO FERNÁNDEZ PRIETO CARLOS AGUIAR EDUARDO DIAS MARIA ISABEL GUTIÉRREZ VILLARÍAS 《Botanical journal of the Linnean Society. Linnean Society of London》2008,157(3):493-499
The majority of authors consider Festuca jubata Lowe as an endemic species common to Madeira and the Azores. Saint-Yves proposed that F. jubata was an Azorean endemic and described a geovicarious taxon in Madeira: F. filiformis C. Sm. ex Link in Buch ssp. mandonii St.-Yves. We undertook a complete bibliographical revision of the taxonomy, nomenclature, and chorology of F. jubata s.l. , and contrasted it with morphological and anatomical studies performed on samples from the Azores and Madeira. Azorean plants usually identified as F. jubata had a character combination distinct from that of those with a Madeiran provenance. Saint-Yves' proposal of two independent taxa was correct, but he erroneously considered F. jubata as an Azorean endemic because the name F. jubata was based on Madeiran plants. Consequently, F. jubata auct. pl. from the Azores belongs to a new species. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 493–499. 相似文献
28.
DESCRIPTION OF THE SENSORY CHARACTERISTICS OF SPANISH UNIFLORAL HONEYS BY FREE CHOICE PROFILING 总被引:1,自引:0,他引:1
MIGUEL ANGEL GONZÁLEZ-VIÑAS AIDA MOYA MARIA DOLORES CABEZUDO 《Journal of sensory studies》2003,18(2):103-113
Different Spanish unifloral honeys (eucalyptus, sunflower, rosemary, thyme, lavender, citrus, anise, quercus, and lemon blossom) and one multifloral honey were studied by Free-Choice Profiling (FCP) analysis. Generalized Procrustes Analysis (GPA) applied to the FCP data allowed discrimination between samples and provided information on the attributes responsible for the differences observed. The honeys had significantly different sensory characteristics. Textural attributes were the predominant factor in discriminating between samples, and appearance (color included) was also correlated with GPA dimensions to a lesser extent. 相似文献
29.
Reproductive ecology of Rhododendron ponticum (Ericaceae) in relict Mediterranean populations 总被引:2,自引:0,他引:2
JOSÉ A. MEJÍAS JUAN ARROYO FERNANDO OJEDA† 《Botanical journal of the Linnean Society. Linnean Society of London》2002,140(3):297-311
In the southern Iberian Peninsula, Rhododendron ponticum occurs in restricted and vulnerable populations as a Tertiary relict. Population structure and the main phases of the reproductive process were examined in order to shed light on recruitment patterns and limitations. Rhododendron ponticum flowers are self-compatible and attract a diverse array of insects, which are responsible for a considerable number of seeds set in the populations. Nevertheless, only adults form populations, whilst seedlings are scarce and saplings virtually absent (only two juveniles out of 2489 adults sampled). Non-specialized vegetative multiplication by layering was observed. Recruitment failure seems to depend on the scarcity of safe microsites, which are free from drought, for seedling establishment. The observations contrast with R. ponticum 's reputation as an aggressive invader in temperate Atlantic areas. It is proposed that the species shows a variable balance between sexual reproduction and vegetative multiplication depending on environmental conditions. At present, only the latter seems to be prevailing in relict populations in the Iberian Peninsula. This flexible reproductive strategy is also discussed as a mechanism allowing persistence during geological climatic oscillations. © The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 140 , 297–311. 相似文献
30.
Rafael Bielza Galindo Jesús Llorente Gutiérrez José Luis Pérez González Asunción Mora Casado David Blanco Díaz Javier Escalera Alonso Adoración Morales Fernández Cristina Molano Ortiz Beredys Esmirla García López Nazaret del Amo del Arco Juan Pablo Barro Ordovas Estefanía Arias Muñana Marta Neira Álvarez David Sanz Rosa Jorge Fco. Gómez Cerezo 《Revista espa?ola de geriatría y gerontología》2018,53(1):38-44