111 research outputs found
The palynological characterization and the pollen germination process of lily hybrid STAR GAZER
This paper presents the morphological characteristics of pollen of lily, hybrid Star Gazer: shape of pollen grains, exine
ornamentation, size of pollen grain and number of germinative pores/pollen grain. Also on presents the characteristics
of pollen germination process of the lily, hybrid Star Gazer. In this regard were carried pollen germination tests "in
vitro" in wet rooms "van Tieghem." The nutrient medium that were used for inoculation of the pollen grains had
different concentrations of sucrose, resulting several experimental variants. The pollen germination capacity was
determined from time to time, thereby establishing the dynamics of this process for four days. Surprising was the fact
that the highest values of germination potential were realized on medium without sugar. On the nutrient mediums with
a moderate concentration in sucrose, the germination capacity of the hybrid lily was inhibited. During the first 24 hours
after inoculation of the medium pollen occurs a significantly improved the pollen germination rate. In parallel with the
determination of pollen germination capacity was analyzed and increasing the length of pollen tubes. This dynamic was
also analyzed for four days. The longest pollen tubes were formed on the medium without sugar. As in the case of the
germinating potential, after 24 hours from the inoculation of the pollen on medium has achieved a significant elongation
of pollen tubes. Also, there is a direct and close corelation between the pollen tube length and the flower style length of
the of which that they have to traverse in order to reach the ovul. The length of Lilium Star Gazer pollen tubes is
positively correlated also with germination rat
Altitude and growth: A study of the patterns of physical growth of a high altitude Peruvian Quechua population
Data on physical growth were obtained for a sample of 1202 Quechua subjects, aged 2 to 35 years from the district of NuĂoa, Puno, located in the southern highlands (altitude 4000â5500m) of Peru. These data were supplemented by a three-year longitudinal study of 300 subjects, aged 1 to 22 years. The patterns of physical growth of members of the indigenous population of NuĂoa are characterized by (1) late sexual dimorphism, (2) slow and prolonged growth in body size, (3) late and poorly defined adolescent stature spurt in both males and females, and (4) accelerated development in chest size. The socio-economic factors associated with urban-rural and altitude differences appear to be reflected in greater deposition of subcutaneous fat and increased weight but do not seem to influence the development of stature. We suggest the pattern of growth of this population is related to the hypoxic effects of high altitude, and/or reflects a genetic adaptation to such stress. The anthropometric and physiological studies conducted during this and previous studies and the comparative data from Peruvian populations situated at lower altitudes document the specific adaptive response of the chest wall to the hypoxic effects of high altitude.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/37500/1/1330320217_ftp.pd
PlnTFDB: updated content and new features of the plant transcription factor database
The Plant Transcription Factor Database (PlnTFDB; http://plntfdb.bio.uni-potsdam.de/v3.0/) is an integrative database that provides putatively complete sets of transcription factors (TFs) and other transcriptional regulators (TRs) in plant species (sensu lato) whose genomes have been completely sequenced and annotated. The complete sets of 84 families of TFs and TRs from 19 species ranging from unicellular red and green algae to angiosperms are included in PlnTFDB, representing >1.6 billion years of evolution of gene regulatory networks. For each gene family, a basic description is provided that is complemented by literature references, and multiple sequence alignments of protein domains. TF or TR gene entries include information of expressed sequence tags, 3D protein structures of homologous proteins, domain architecture and cross-links to other computational resources online. Moreover, the different species in PlnTFDB are linked to each other by means of orthologous genes facilitating cross-species comparisons
Minimization of free radical damage by metal catalysis of multivitamin/multimineral supplements
Multivitamin/multimineral complexes are the most common dietary supplements. Unlike minerals in foods that are incorporated in bioorganic structures, minerals in dietary supplements are typically in an inorganic form. These minerals can catalyze the generation of free radicals, thereby oxidizing antioxidants during digestion. Here we examine the ability of a matrix consisting of an amino acid and non-digestible oligosaccharide (AAOS) to blunt metal-catalyzed oxidations. Monitoring of ascorbate radical generated by copper shows that ascorbate is oxidized more slowly with the AAOS matrix than with copper sulfate. Measurement of the rate of oxidation of ascorbic acid and TroloxÂź by catalytic metals confirmed the ability of AAOS to slow these oxidations. Similar results were observed with iron-catalyzed formation of hydroxyl radicals. When compared to traditional forms of minerals used in supplements, we conclude that the oxidative loss of antioxidants in solution at physiological pH is much slower when AAOS is present
Physical mapping and BAC-end sequence analysis provide initial insights into the flax (Linum usitatissimum L.) genome
<p>Abstract</p> <p>Background</p> <p>Flax (<it>Linum usitatissimum </it>L.) is an important source of oil rich in omega-3 fatty acids, which have proven health benefits and utility as an industrial raw material. Flax seeds also contain lignans which are associated with reducing the risk of certain types of cancer. Its bast fibres have broad industrial applications. However, genomic tools needed for molecular breeding were non existent. Hence a project, Total Utilization Flax GENomics (TUFGEN) was initiated. We report here the first genome-wide physical map of flax and the generation and analysis of BAC-end sequences (BES) from 43,776 clones, providing initial insights into the genome.</p> <p>Results</p> <p>The physical map consists of 416 contigs spanning ~368 Mb, assembled from 32,025 fingerprints, representing roughly 54.5% to 99.4% of the estimated haploid genome (370-675 Mb). The N50 size of the contigs was estimated to be ~1,494 kb. The longest contig was ~5,562 kb comprising 437 clones. There were 96 contigs containing more than 100 clones. Approximately 54.6 Mb representing 8-14.8% of the genome was obtained from 80,337 BES. Annotation revealed that a large part of the genome consists of ribosomal DNA (~13.8%), followed by known transposable elements at 6.1%. Furthermore, ~7.4% of sequence was identified to harbour novel repeat elements. Homology searches against flax-ESTs and NCBI-ESTs suggested that ~5.6% of the transcriptome is unique to flax. A total of 4064 putative genomic SSRs were identified and are being developed as novel markers for their use in molecular breeding.</p> <p>Conclusion</p> <p>The first genome-wide physical map of flax constructed with BAC clones provides a framework for accessing target loci with economic importance for marker development and positional cloning. Analysis of the BES has provided insights into the uniqueness of the flax genome. Compared to other plant genomes, the proportion of rDNA was found to be very high whereas the proportion of known transposable elements was low. The SSRs identified from BES will be valuable in saturating existing linkage maps and for anchoring physical and genetic maps. The physical map and paired-end reads from BAC clones will also serve as scaffolds to build and validate the whole genome shotgun assembly.</p
D Optical Turbulence
Not much is known about the typical horizontal size of the turbulence at different altitudes of the troposphere. It was recently shown (Masciadri et al., 2000, Masciadri, 2001a), using a numerical simulation (Meso-Nh model), that the hypothesis of considering horizontally uniform C N can have severe consequences. For example, the integration of the C N along lines of sight different from the zenith gives variations that can be larger than 0.5 arcsec. The confirmation of this thesis would have fundamental consequences for new adaptive optics techniques, particularly in applications to large size telescopes such as the OWL. In order to validate this result, in this contribution we compare measured and simulated C N profiles. The first ones were obtained with a Generalized Scidar at the San Pedro M'artir Observatory (Mexico) in May 2000 and the latter are simulated at the same azimuth and elevation as those of the observations. The results of this study show that the proposed thesis is confirmed but a further cross-correlation between measurements is suggested. Moreover, for the first time, we show that the model can reproduce observed seeing values that vary as much as 0.5 arcsec during the same night
The Characterization of the Spectrum of a Class of Relations
Hereditary, directed subsets of a group and a semigroup
and some of their properties are discussed. A class of relations
in terms of the range projections of a partial representation
of a discrete group is introduced. It is shown that the spectrum of
these relations is homeomorphic to the set of all characters of the
diagonal subalgebra of the Toeplitz algebra
Complete Coding Sequences of Eastern Equine Encephalitis Virus and Venezuelan Equine Encephalitis Virus Strains Isolated from Human Cases
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