Oleosins and oil bodies in plant seeds have postulated structures.
Explore the source record for details and available documents.
Phospholipids↗
SEARCH · Search PubMed
Results for “Plant Structures”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Large scale molecular analysis of traditional European maize populations. Relationships with morphological variation.
A representative sample of 130 European traditional maize populations was analysed for both their morphological and molecular variation. The morphological analysis of 19 variables revealed a significant variability. Correlation analysis allowed us to distinguish between traits affected by earliness (plant and ear height) and structural traits (plant architecture, grain structure). Two main morphological types could be distinguished. Molecular analyses were performed for 29 RFLP loci on DNA bulks. The number of alleles detected was high when compared to previous studies (9.59 alleles per locus). Genetic diversity was also high (0.55), with a strong differentiation between populations (GST value of 35.6%). A clear relationship between the genetic diversity of the populations and their agronomic performances was highlighted. Morphological and molecular distances showed a tendency towards a triangular relationship. We therefore considered a two-phase process to be the most efficient approach for the classification of genetic resources: firstly, a molecular study to define groups of genetically close populations, and secondly a morphological description of populations from each group. In our European collection, this approach allowed us to separate the populations from Northern and Southern Europe and to define six groups of genetically close populations, comparable to European races. This study opens new prospects concerning the molecular analysis of very large collections of genetic resources, hitherto limited by the necessity of individual analyses, and proposes a first molecular classification of European maize germplasm.
Alleles↗
Signalling events elicited in plants by defined oligosaccharide structures.
Developments during the past year have confirmed that several classes of oligosaccharides are able to activate the plant cell machinery, leading either to defence reactions or to plant developmental processes. Both fungal and plant cell walls contain molecules that elicit plant defence reactions; however, most of the studies focus on the activities induced by lipochito-oligomers (LCOs, or Nod factors) produced by bacteria which trigger plant infection and nodule formation (organogenesis). LCOs can be described as growth regulators of plants in general as they also induce protoplast cell divisions of tobacco plant (a nonlegume) at femtomolar concentrations. Recognition of the appropriate symbiotic bacteria by legumes is mediated by the structure of Nod factors, but the structural determinants involved in this recognition process are not always clearly understood. Although specific substitutions of the oligochitin backbone by several chemical groups are involved, it seems that some host range variations of the bacteria can only be explained by small variations in the hydrophobic balance between both ends of the molecule.
Molecular Structure↗
Structure and function of pectic enzymes: virulence factors of plant pathogens.
The structure and function of Erwinia chrysanthemi pectate lysase C, a plant virulence factor, is reviewed to illustrate one mechanism of pathogenesis at the molecular level. Current investigative topics are discussed in this paper.
Erwinia↗
[Plant biodiversity and community structure of semi-humid evergreen broadleaved forests at different secondary succession stages].
To analyze the relationships between plant diversity and community structure of semi-humid evergreen broadleaved forests at different secondary succession stage in the Samachang area of Yunnan Province, some numeral indices were tested, and the results showed that the plant diversity increased gradually with succession, and the species number reached 24 at the latest succession stage. There was a positive linear correlation between plant individual density and species diversity, which could be described by y = 506. 99x + 554.56. A negative correlation was observed between the average height of plant individuals and plant species diversity, and the equation y = -0. 3862x + 11.406 could describe it well. The crown density and basal area increased in logarithm with plant species diversity, and the two equations y = 21.756 1n x + 11.607 and y = 7.4028 ln x + 9.6198 could describe the relations. No regular patterns were observed for the changes of aboveground biomass and plant individual density with plant species diversity. The relations of plant species with plant individual number could also be described by negative power function. Plant competition was intensified with plant species diversity, and each plant species might take the strategy to conserve its greatest population, and to avoid decreasing to less than its critical population, which led to a high individual density, and might change the structural character of the community.
Biodiversity↗
Plant purple acid phosphatases - genes, structures and biological function.
The properties of plant purple acid phosphatases (PAPs), metallophosphoesterases present in some bacteria, plants and animals are reviewed. All members of this group contain a characteristic set of seven amino-acid residues involved in metal ligation. Animal PAPs contain a binuclear metallic center composed of two irons, whereas in plant PAPs one iron ion is joined by zinc or manganese ion. Among plant PAPs two groups can be distinguished: small PAPs, monomeric proteins with molecular mass around 35 kDa, structurally close to mammalian PAPs, and large PAPs, homodimeric proteins with a single polypeptide of about 55 kDa. Large plant PAPs exhibit two types of structural organization. One type comprises enzymes with subunits bound by a disulfide bridge formed by cysteines located in the C-terminal region around position 350. In the second type no cysteines are located in this position and no disulfide bridges are formed between subunits. Differences in structural organisation are reflected in substrate preferences. Recent data reveal in plants the occurrence of metallophosphoesterases structurally different from small or large PAPs but with metal-ligating sequences characteristic for PAPs and expressing pronounced specificity towards phytate or diphosphate nucleosides and inorganic pyrophosphate.
Acid Phosphatase↗
Phase I study of thalicarpine (NAC-68075), a plant alkaloid of noval structure.
An initial clinical trial of daily and weekly X 6 ihtravenous infusions of thalicarpine, a plant alkaloid of novel structure, was carried out in 36 patients. Twenty-eight patients received 33 courses of single-dose administration at doses of 200-1900 mg/m2. At the maximum tolerable dose of 1400 mg/m2, toxic effects included arm pain (nine or ten), central nervous system depression (seven of ten), nausea and vomiting (two of ten), hypotension (two of ten), hypertension (two of ten), arrhythmia (premature ventricular contractions) (one of ten), and electrocardiographic changes (mainly T-wave flattening) (five of ten). At the maximum tolerable dose for weekly administration, 1100 mg/m2/week X 6, arm pain was seen in seven of eight, central nervous system depression in three of eight, hypotension in one of eight, and electrocardiographic changes in three of eight. The recommended dose for phase II trials is 1100 mg/m2/week by a 2-hour intravenous infusion.
Adult↗
Structure and function of plant canopies.
This section comprises a set of papers taken from those presented at a symposium held to commemorate the 50th anniversary of the Monsi-Saeki theory (1953), together with invited papers. The papers describe recent advances in the study of structure and function of plant canopies and are written by former students (and their collaborators) of Professors Monsi and Saeki. The topics cover construction and maintenance of efficient photosynthetic systems at leaf, individual plant and stand level. Canopy structure and function are analysed with respect to optimization and an evolutionarily stable strategy. A new translation of the original paper by Monsi and Saeki (1953) into English has been commissioned and is included in this section.
Botany↗
Structure and evolution of plant disease resistance genes.
This article reviews recent advances that shed light on plant disease resistance genes, beginning with a brief overview of their structure, followed by their genomic organization and evolution. Plant disease resistance genes have been exhaustively investigated in terms of their structural organization, sequence evolution and genome distribution. There are probably hundreds of NBS-LRR sequences and other types of R-gene-like sequences within a typical plant genome. Recent studies revealed positive selection and selective maintenance of variation in plant resistance and defence-related genes. Plant resistance genes are highly polymorphic and have diverse recognition specificities. R-genes occur as members of clustered gene families that have evolved through duplication and diversification. These genes appear to evolve more rapidly than other regions of the genome, and domains such as the leucine-rich repeat, are subject to adaptive selection
Evolution, Molecular↗
Purification, characterization, and structural analysis of a plant low-temperature-induced protein.
We have purified to near homogeneity a recombinant form of the protein BN28 (rBN28), expressed in response to low temperature in Brassica napus plants, and we have determined its solution structure. Antibodies raised against rBN28 were used to characterize the recombinant and native proteins. Similar to many other low-temperature-induced proteins, BN28 is extremely hydrophilic, such that it remains soluble following boiling. Immunoblot analysis of subcellular fractions indicated that BN28 was not strongly associated with cellular membranes and was localized exclusively within the soluble fraction of the cell. Contrary to predicted secondary structure that suggested significant helical content, circular dichroism analysis revealed that rBN28 existed in aqueous solution largely as a random coil. However, the helical propensity of the protein could be demonstrated in the presence of trifluoroethanol. Nuclear magnetic resonance analysis further showed that rBN28 was in fact completely unstructured (100% coil) in aqueous solution. Although it had earlier been speculated that BN28-like proteins from Arabidopsis thaliana might possess antifreeze protein activity (S. Kurkela and M. Franck [1990] Plant Mol Biol 15: 137-144), no such activity could be detected in ice recrystallization assays with rBN28.
Amino Acid Sequence↗
The calculation of plant 5S rRNAs secondary structure.
Using commercially available computer software package for ribonucleic acid (RNA) secondary structure analysis we calculated the free energy (delta G) of all higher plant 5S rRNA species. To gain insight into the relation between structure (nucleotide sequence) and free energy we generated point mutants of plant 5S rRNA and calculated their secondary structure. This analysis permitted to identify single sites which affect the stability and conformation of RNA molecule. Furthermore, the calculated data were compared with the electrophoretic mobility of 5S rRNA on polyacrylamide gels.
Base Sequence↗
Flavonoids and andrographolides from Andrographis paniculata.
Two flavonoids, identified as 5,7,2',3'-tetramethoxyflavanone and 5-hydroxy-7,2',3'-trimethoxyflavone, as well as several other flavonoids, andrographolide diterpenoids, and polyphenols, were obtained from the phytochemical investigation of the whole plant of Andrographis paniculata, a well known medicinal plant. The structures of these compounds were established with the aid of spectroscopic methods, including analysis by 2D NMR spectroscopy.
Andrographis↗
Structural characterization of plant-derived hepatitis B surface antigen employed in oral immunization studies.
Several subunit vaccine antigens have been successfully expressed in plants and recently the hepatitis B surface antigen (HBsAg), expressed in potatoes, was shown to be orally immunogenic in animal studies. However, to date, a detailed analysis of the plant-derived antigen is lacking. Herein, we comprehensively characterize the structure and post-translational processing of HBsAg from potato tuber and two plant cell suspension cultures. The HBsAg was found to accumulate intracellularly as tubular structures, with a complex size distribution, differing substantially from the virus-like particle (VLP) preparations of the current commercial vaccines. Extensive disulfide-bond cross-linking, which is important for immunogenicity, was evident and 21-37% of total HBsAg protein displayed epitopes which correlate with vaccine potency. The significance of these results with regard to the production of cost-effective orally delivered vaccines is discussed.
Administration, Oral↗
Host and parasite population structure in a natural plant-pathogen system
We investigated the genetic population structure in a metapopulation of the plant Silene latifolia (Caryophyllaceae) and its fungal pathogen Microbotryum violaceum (Ustilaginales), a pollinator-borne disease. Population structure of the host plant was estimated using allozyme markers and that of the fungus by microsatellites. Both host and parasite showed significant differentiation, but parasite populations were 12 times more strongly differentiated than those of the hosts. We found significant isolation by distance for host populations but not for parasite populations. Higher population differentiation for the parasite may result from small effective population size, high selfing rates, or low migration rate. In this system, hosts are obligate outcrossers and they migrate by seeds and pollen, whereas parasites can self-fertilize and migrate only on pollinating insects. We discuss the effect of limited gene flow in this parasite on its coevolutionary interaction with its host, and its potential for local adaptation on sympatric host populations.
Journal Article↗
Rapid changes in flowering time in British plants.
The average first flowering date of 385 British plant species has advanced by 4.5 days during the past decade compared with the previous four decades: 16% of species flowered significantly earlier in the 1990s than previously, with an average advancement of 15 days in a decade. Ten species (3%) flowered significantly later in the 1990s than previously. These data reveal the strongest biological signal yet of climatic change. Flowering is especially sensitive to the temperature in the previous month, and spring-flowering species are most responsive. However, large interspecific differences in this response will affect both the structure of plant communities and gene flow between species as climate warms. Annuals are more likely to flower early than congeneric perennials, and insect-pollinated species more than wind-pollinated ones.
Climate↗
[The structure and function of plant WRKY transcription factors].
WRKY transcription factors that are unique to plants are the new type transcriptional regulatory factors in which N-terminal ends contain a conserved WRKYGQR amino acids sequences. WRKY transcription factors regulate the target genes expression that contain the W-box elements in the promoter regions by specifically binding to (T)(T)TGAC(C/T) sequence. Therefore, the WRKY transcription factors participate in the plant various kinds defense responses and regulate the plant growth and development. This article reviews the progress of the basic structure and biological function of plant WRKY transcription factors.
Plant Development↗
Comparative molecular and phytochemical investigation of Leontodon autumnalis (Asteraceae, Lactuceae) populations from Central Europe.
Previous analyses of Leontodon autumnalis L. revealed the existence of two chemotypes. In the current study molecular and phytochemical methods were combined to investigate 24 Central European populations of L. autumnalis. The focus of this study was the correlation of molecular and phytochemical characters at the intraspecific level. DNA fingerprint profiles of 183 individuals were obtained by random amplified polymorphic DNA (RAPD) providing 77 molecular markers. Contents of phenolics and sesquiterpenoids of flowering heads and sub-aerial parts were quantified by HPLC-DAD analyses. HPLC results were evaluated by principal component analysis. Geographic distribution of the two detected chemotypes partially overlapped. Phylogenetic groupings displayed in an unrooted neighbor-joining tree calculated from the RAPD data matrix were correlated with the geographical origin of the plant material. However, genetic profiles neither correlated with the two chemotypes nor with the morphologically based subspecies of L. autumnalis recognized by some authors. The presented data imply that the morphotypes are of multiple origins or due to different ecological growing conditions rather than genetically determined and that phytochemical races are induced by a limited number of genetical differences, which might have occurred independently in different lineages of the L. autumnalis group.
Asteraceae↗
Analysis of the secondary structure of expansion segment 39 in ribosomes from fungi, plants and mammals.
The structure of expansion segment 39, ES39, in eukaryotic 23 S-like ribosomal RNA was analysed using a combination of chemical and enzymic reagents. Ribosomes were isolated from yeast, wheat, mouse, rat and rabbit, five organisms representing three different eukaryotic kingdoms. The isolated ribosomes were treated with structure-sensitive chemical and enzymic reagents and the modification patterns analysed by primer extension and gel electrophoresis on an ABI 377 automated DNA sequencer. The expansion segment was relatively accessible to modification by both enzymic and chemical probes, suggesting that ES39 was exposed on the surface of the ribosomes. The collected modification data were used in secondary structure modelling of the expansion segment. Despite considerable variation in both sequence and length between organisms from different kingdoms, the structure analysis of the expansion segment gave rise to structural fingerprints that allowed identification of homologous structures in ES39 from fungi, plants and mammals. The homologous structures formed an initial helix and an invariant hairpin connected to the initial helix via a long single-stranded loop. The remaining part of the ES39 sequences accounted for most of the length variation seen between the analysed species. This part could form additional, albeit less similar, hairpins. A comparison of ES39 sequences from other fungi, plants and mammals showed that identical structures could be formed in these organisms.
Animals↗