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31.
In that data were not available on the vitamin E status of young children, the aim of the study was to evaluate the vitamin E status of preschool children by three commonly used criteria: vitamin E intakes, plasma alpha-tocopherol concentrations and plasma alpha-tocopherol/total lipid ratios. Twenty-two ethnically diverse preschool children (13 males and 9 females), aged 2 to 5 years, living in Lincoln, NE, served as subjects. The subjects were in two groups: 2-3 and 4-5 years old. Energy, fat, and alpha- and gamma-tocopherol intakes of the subjects were estimated utilizing two 24-h food recalls. Plasma alpha- and gamma-tocopherol and total lipid concentrations were ascertained. No significant differences by age grouping or gender were observed for vitamin E intakes, plasma alpha-tocopherol concentrations, plasma gamma-tocopherol concentrations and plasma alpha-tocopherol/total lipid ratios of subjects. Plasma alpha-tocopherol concentrations indicative of less than adequate status (<12 micromol/L) were observed in 91% of the children, and values <7 micromol/L (proposed cutoff for pediatric populations) in 68%. Sixty-eight percent of the subjects had plasma alpha-tocopherol/total lipid values <0.8 mg/g. The majority of the 2- to 5-year-old children included in the study had less than adequate vitamin E status.  相似文献   
32.
Surveys of larval diversity consistently increase biodiversity estimates when applied to poorly documented groups of marine invertebrates such as phoronids and hemichordates. However, it remains to be seen how helpful this approach is for detecting unsampled species in well‐studied groups. Echinoids represent a large, robust, well‐studied macrofauna, with low diversity and low incidence of cryptic species, making them an ideal test case for the efficacy of larval barcoding to discover diversity in such groups. We developed a reference dataset of DNA barcodes for the shallow‐water adult echinoids from both coasts of Panama and compared them to DNA sequences obtained from larvae collected primarily on the Caribbean coast of Panama. We sequenced mitochondrial cytochrome c oxidase subunit I (COI) for 43 species of adult sea urchins to expand the number and coverage of sequences available in GenBank. Sequences were successfully obtained for COI and 16S ribosomal DNA from 272 larvae and assigned to 17 operational taxonomic units (OTUs): 4 from the Pacific coast of Panama, where larvae were not sampled as intensively, and 13 from the Caribbean coast. Of these 17 OTUs, 13 were identified from comparisons with our adult sequences and belonged to species well documented in these regions. Another larva was identified from comparisons with unpublished sequences in the Barcode of Life Database (BOLD) as belonging to Pseudoboletia, a genus scarcely known in the Caribbean and previously unreported in Panama. Three OTUs remained unidentified. Based on larval morphology, at least two of these OTUs appeared to be spatangoids, which are difficult to collect and whose presence often goes undetected in standard surveys of benthic diversity. Despite its ability to capture unanticipated diversity, larval sampling failed to collect some species that are locally common along the Caribbean coast of Panama, such as Leodia sexiesperforata, Diadema antillarum, and Clypeaster rosaceus.  相似文献   
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The challenge of constructing large phylogenetic trees   总被引:3,自引:0,他引:3  
The amount of sequence data available to reconstruct the evolutionary history of genes and species has increased 20-fold in the past decade. Consequently the size of phylogenetic analyses has grown as well, and phylogenetic methods, algorithms and their implementations have struggled to keep pace. Computational and other challenges raised by this burgeoning database emerge at several stages of analysis, from the optimal assembly of large data matrices from sequence databases, to the efficient construction of trees from these large matrices and the piece-wise assembly of 'supertrees' from those trees in turn. A final challenge is posed by the difficulty of visualizing and making inferences from trees that might soon routinely contain thousands of species.  相似文献   
35.

Background  

Bacille Calmette-Guerin (BCG) is currently the only available vaccine against tuberculosis (TB) and comprises a heterogeneous family of sub-strains with genotypic and phenotypic differences. The World Health Organization (WHO) affirms that the characterization of BCG sub-strains, both on genomic and proteomic levels, is crucial for a better comprehension of the vaccine. In addition, these studies can contribute in the development of a more efficient vaccine against TB. Here, we combine two-dimensional electrophoresis (2DE) and mass spectrometry to analyse the proteomic profile of culture filtrate proteins (CFPs) from M. bovis BCG Moreau, the Brazilian vaccine strain, comparing it to that of BCG Pasteur. CFPs are considered of great importance given their dominant immunogenicity and role in pathogenesis, being available for interaction with host cells since early infection.  相似文献   
36.
The vangas of Madagascar exhibit extreme diversity in morphology and ecology. Recent studies have shown that several other Malagasy species also are part of this endemic radiation, even as the monophyly of the clade remains in question. Using DNA sequences from 13 genes and representatives of all 15 vanga genera, we find strong support for the monophyly of the Malagasy vangids and their inclusion in a family along with six aberrant genera of shrike-like corvoids distributed in Asia and Africa. Biogeographic reconstructions of these lineages include both Asia and Africa as possible dispersal routes to Madagascar. To study patterns of speciation through time, we introduce a method that can accommodate phylogenetically non-random patterns of incomplete taxon sampling in diversification studies. We demonstrate that speciation rates in vangas decreased dramatically through time following the colonization of Madagascar. Foraging strategies of these birds show remarkable congruence with phylogenetic relationships, indicating that adaptations to feeding specializations played a role in the diversification of these birds. Vangas fit the model of an 'adaptive radiation' in that they show an explosive burst of speciation soon after colonization, increased diversification into novel niches and extraordinary ecomorphological diversity.  相似文献   
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Human enteric virus infections range from gastroenteritis to life threatening diseases such as myocarditis and aseptic meningitis. Rotavirus is one of the most common enteric agents and mortality associated with infection can be very significant in developing countries. Most enteric viruses produce diseases that are not distinct from other pathogens, and current diagnostics is limited in breadth and sensitivity required to advance virus detection schemes for disease intervention strategies. A spectroscopic assay based on surface enhanced Raman scattering (SERS) has been developed for rapid and sensitive detection of rotavirus. The SERS method relies on the fabrication of silver nanorod array substrates that are extremely SERS-active allowing for direct structural characterization of viruses. SERS spectra for eight rotavirus strains were analyzed to qualitatively identify rotaviruses and to classify each according to G and P genotype and strain with >96% accuracy, and a quantitative model based on partial least squares regression analysis was evaluated. This novel SERS-based virus detection method shows that SERS can be used to identify spectral fingerprints of human rotaviruses, and suggests that this detection method can be used for pathogen detection central to human health care.  相似文献   
39.

Background  

Hepatitis C virus (HCV) currently infects approximately three percent of the world population. In view of the lack of vaccines against HCV, there is an urgent need for an efficient treatment of the disease by an effective antiviral drug. Rational drug design has not been the primary way for discovering major therapeutics. Nevertheless, there are reports of success in the development of inhibitor using a structure-based approach. One of the possible targets for drug development against HCV is the NS3 protease variants. Based on the three-dimensional structure of these variants we expect to identify new NS3 protease inhibitors. In order to speed up the modeling process all NS3 protease variant models were generated in a Beowulf cluster. The potential of the structural bioinformatics for development of new antiviral drugs is discussed.  相似文献   
40.
The light subunit of mushroom, Agaricus bisporus, tyrosinase (LSMT), has been identified as an extrinsic component of the enzyme. Its function is unknown, but it can cross an epithelial cell layer, which suggests that it can be absorbed by the intestine. A similar capability has been demonstrated for the HA-33 component of the progenitor toxin from Clostridium botulinum, which is the closest structural homolog of LSMT. Unlike HA-33, LSMT appears to be non-immunogenic as shown by preliminary tests in Swiss Webster mice. We investigated the immunogenicity and histopathology of LSMT in mice to determine its safety in vivo. LSMT did not evoke generation of antibodies after prolonged periods of intraperitoneal administration. Histopathological observations confirmed the absence of responses in organs after twelve weekly administrations of LSMT. We found that LSMT is not toxic and is less immunogenic than the C. botulinum HA-33 protein, which supports further research and development for pharmaceutical application.  相似文献   
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