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At least 1,261 records · Page 70Linked to original sources
PubMed1995

Primary structure, sequence-specific 1H-NMR assignments and secondary structure in solution of bromelain inhibitor VI from pineapple stem.

One of the bromelain inhibitors, isoinhibitor VI (BI-VI), was purified from pineapple stem powder and its complete amino acid sequence was determined by conventional protein sequencing. These results revealed that the protein consists of an 11-residue light chain and a 41-residue heavy chain, cross-linked to each other by disulfide bonds to form the native inhibitor of 52 residues (M(r) = 5888). The secondary structure of BI-VI was analyzed based on the sequence-specific 1H resonance assignment of its two-dimensional NMR spectra. BI-VI was shown to be composed of two domains (A and B) which are formed by antiparallel beta-sheets, but has no alpha-helix. These results were consistent with the CD spectra of BI-VI. Residues Lys27-Ile29 (heavy chain) form a triple-stranded antiparallel beta-sheet with residues Asp9-Tyr11 and Lys22-Glu24 (heavy chain) in the A domain and residues Cys5-Cys7 (heavy chain) form another triple-stranded beta-sheet with residues Cys6-Cys8 (light chain) and Asp32-Ile34 (heavy chain) in the B domain. The secondary structure as well as the primary structure of BI-VI was distinctly different from that of the other cysteine protease inhibitor, cystatin, and from that of basic pancreatic trypsin inhibitor.

Amino Acid Sequence↗
PubMed1994

Antimicrobial activity of natural and semisynthetic diterpenoids from Sideritis spp.

The antimicrobial activity of 22 natural diterpenoids of endemic Sideritis from Eastern Andalusia (Spain) is described. Only ent-kaur-16-ene foliol and ent-beyer-15-ene isopusillatriol proved to be active towards Gram-positive and acid-fast bacteria. The introduction of a ketonic group at C-15 on ent-kaur-16-enic systems produced a remarkable degree of activity.

Anti-Bacterial Agents↗
PubMed2004

Conversion of the carbohydrate structures of glycoproteins in roots of Raphanus sativus using several glycosidase inhibitors.

An attempt was made to convert the N-glycan structures in Raphanus sativus seeds during germination with a view to develop a method for regulating the N-glycan structures using glycosidase inhibitors. The N-glycan structures of glycoproteins in the roots of seedlings germinated for three days were analyzed by hydrazinolysis followed by N-acetylation, pyridylamination and HPLC. Pyridylaminated sugar chains obtained in the absence of the inhibitors had plant type structures consisting of Man(3)FucXylGlcNAc(2)(M3FX), Man(5-9)GlcNAc(2)(high-Man) and GlcNAc(1-2)Man(3)FucXylGlcNAc(2)(GnM3FX and Gn2M3FX). When germinated in the presence of a glucosidase inhibitor (castanospermine or deoxynojirimycin), the amount of glucosyl high-Man-type structure increased and plant growth was inhibited. When germinated in the presence of a mannosidase inhibitor (swainsonine or deoxymannojirimycin), the amount of the high-Man-type structure increased and that of M3FX was low, and the growth was normal. In the presence of 2-acetamido 1, 2 di-deoxynojirimycin, those of GnM3FX and Gn2M3FX increased and the growth was normal. These results show that the N-glycan processing in both the endoplasmic reticulum (ER) and Golgi apparatus can be controlled artificially using glycosidase inhibitors, and that the glucosidase inhibitors could be useful for the study of the function of N-glycans in plants.

1-Deoxynojirimycin↗
PubMedDate not supplied

[The comparative structural-functional characteristics of the cytoskeleton of animals and higher plants].

The peculiarities of structure, location and dynamics of microtubules (Mts) and microfilaments (Mfs) in cells of animals and of higher plants (growing by elongation and apical growth) are discussed. It is shown that in animal cells Mt-skeleton located mainly in the depths of the cytoplasm is responsible for directed intracellular movement and characteristic position of cell components. Animal Mf-skeleton forming a dense network is most often aggregated at the cell periphery. Its primary function is the shaping and locomotion of the cell. In contrast, one of the most characteristic features of the cytoskeleton in the elongating plant cells is the presence of only cortical Mts closely linked to the plasmalemma. Higher plant Mt-skeleton is involved primarily in the orientation of newly depositing cellulosic cell wall microfibrils and thus it controls the direction of cell growth which determines the cell shape. It also mediates (by means of preprophase Mt-band) the orientation of cytokinesis. Thus in plants the principal role of the Mt-skeleton is the control of morphogenesis. Far less important is supporting function of plant Mts. The nuclear envelope is main Mt organizing center in plant cells. Unlike Mts, plant Mf-skeleton is concentrated in the cell depths and is the involved in the intracellular transport and characteristic positioning of the cell components. Apically growing cells such as root hairs typically contain deeply distributed Mts in addition to cortical ones. The former may participate in the transfer of nucleus and/or plastids.

Animals↗
PubMed2006

[Variation of both DNA genetic structure and reproduction traits of plant autotetraploid].

Due to the effect of chromosome doubling, the DNA genetic structures of autotetraploid vary from its original diploid, and thus autotetraploid phenotype changes correspondingly. Compared with original diploid, the phenotype changes of autotetraploid were as follows. The part of its male and female gametes was of abortion. Its pollen (diplo-haplont) was significantly bigger. The number of egg cells or synergids or antipodal cells in its embryo sacs increases or reduces. While self-crossing procreation of it, pollen tubes and the fertilization processes of polar nucleus and the fertilized cells development were partly abnormal. Its reproductive capacity (or seed setting rate) dropped to some extents, which can be gradually improved with generations. For some plant species, it has a better cross-compatibility in distant hybridizations.

DNA, Plant↗
PubMed2004

Plant genetic differences influence herbivore community structure: evidence from a hybrid willow system.

To determine the influence of plant genetic variation on community structure of insect herbivores, we examined the abundances of 14 herbivore species among six genetic classes of willow: Salix eriocephala, S. sericea, their F(1) and F(2) interspecific hybrids, and backcross hybrids to each parental species. We placed 1-year-old plants, grown from seeds generated from controlled crosses, in a common garden. During the growing season, we censused gall-inducing flies and sawflies, leaf-mining insects, and leaf-folding Lepidoptera to determine the community structure of herbivorous insects on the six genetic classes. Our results provided convincing evidence that the community structure of insect herbivores in this hybrid willow system was shaped by genetic differences among the parental species and the hybrid genetic classes. Using MANOVA, we detected significant differences among genetic classes for both absolute and relative abundance of herbivores. Using canonical discriminant analysis, we found that centroid locations describing community structure of the insect herbivores differed for each genetic class. Moreover, the centroids for the four hybrid classes were located well outside of the range between the centroids for the parental species, suggesting that more than additive genetic effects of the two parental species influenced community formation on hybrid classes. Line-cross analysis suggested that plant genetic factors responsible for structuring the herbivore community involved epistatic effects, as well as additive and dominance effects. We discuss the ramifications of these results in regard to the structure of insect herbivore communities on plants and the implications of our findings for the evolution of interspecific interactions.

Animals↗
PubMed2003

Complete sequence analysis of transgene loci from plants transformed via microprojectile bombardment.

A substantial literature exists characterizing transgene locus structure from plants transformed via Agrobacterium and direct DNA delivery. However, there is little comprehensive sequence analysis of transgene loci available, especially from plants transformed by direct delivery methods. The goal of this study was to completely sequence transgene loci from two oat lines transformed via microprojectile bombardment that were shown to have simple transgene loci by Southern analysis. In line 3830, transformed with a single plasmid, one major and one of two minor loci were completely sequenced. Both loci exhibited rearranged delivered DNA and flanking genomic sequences. The minor locus contained only 296 bp of two non-contiguous fragments of the delivered DNA flanked by genomic (filler) DNA that did not originate from the integration target site. Predicted recognition sites for topoisomerase II and a MAR region were observed in the transgene integration target site for this non-functional minor locus. Line 11929, co-transformed with two different plasmids, had a single relatively simple transgene locus composed of truncated and rearranged sequences from both delivered DNAs. The transgene loci in both lines exhibited multiple transgene and genomic DNA rearrangements and regions of scrambling characteristic of complex transgene loci. The similar characteristics of recombined fragments and junctions in both transgenic oat lines implicate similar mechanisms of transgene integration and rearrangement regardless of the number of co-transformed plasmids and the level of transgene locus complexity.

Avena↗
PubMed2003

[Ecological significance of arbuscular mycorrhiza biotechnology in modern agricultural system].

Mycorrhiza plays a key role in nutrient cycling in ecosystem, and protects host plant against environmental stress. Under natural condition, plant's mycorrhizal structure is a normal phenomenon, and arbuscular mycorrhiza (AM) association is the commonest mycorrhizal type. If well mycorrhizal structure can be formed during plant root system developing process, the quantity and quality of plant production will be improved in large. Because of its effects on plant growth and health, it is accepted that AM symbiosis can reduce chemical fertilizer and pesticide inputs. Consequently, this will lead to a reduction in harmful chemical substance impact on environment. The key effects of AM symbiosis can be summarized as follows: (1) improving rooting and plant establishment; (2) improving uptake of low mobile ions; (3) improving nutrient cycling; (4) enhancing plant tolerance to (biotic and abiotic) stress; (5) improving quality of soil structure; and (6) enhancing plant community diversity. In this paper, the ecological characteristic of arbuscular mycorrhiza fungi (AMF), effects of AM on host plant, and ecologic significance of AM biotechnology in agricultural system were reviewed.

Absorption↗
PubMed1999

N-Glycosylation of a mouse IgG expressed in transgenic tobacco plants.

Since plants are emerging as an important system for the expression of recombinant glycoproteins, especially those intended for therapeutic purposes, it is important to scrutinize to what extent glycans harbored by mammalian glycoproteins produced in transgenic plants differ from their natural counterpart. We report here the first detailed analysis of the glycosylation of a functional mammalian glycoprotein expressed in a transgenic plant. The structures of the N-linked glycans attached to the heavy chains of the monoclonal antibody Guy's 13 produced in transgenic tobacco plants (plantibody Guy's 13) were identified and compared to those found in the corresponding IgG1 of murine origin. Both N-glycosylation sites located on the heavy chain of the plantibody Guy's 13 are N-glycosylated as in mouse. However, the number of Guy's 13 glycoforms is higher in the plant than in the mammalian expression system. Despite the high structural diversity of the plantibody N-glycans, glycosylation appears to be sufficient for the production of a soluble and biologically active IgG in the plant system. In addition to high-mannose-type N-glycans, 60% of the oligosaccharides N-linked to the plantibody have beta(1, 2)-xylose and alpha(1, 3)-fucose residues linked to the core Man3GlcNAc2. These plant-specific oligosaccharide structures are not a limitation to the use of plantibody Guy's 13 for topical immunotherapy. However, their immunogenicity may raise concerns for systemic applications of plantibodies in human.

Animals↗
PubMed2004

Photosynthetic evolution in parasitic plants: insight from the chloroplast genome.

Despite the enormous diversity in plant form, structure and growth environment across the seed-bearing plants (angiosperms and gymnosperms), the chloroplast genome has, with few exceptions, remained remarkably conserved. This conservation suggests the existence of universal evolutionary selection pressures associated with photosynthesis-the primary function of chloroplasts. The stark exceptions to this conservation occur in parasitic angiosperms, which have escaped the dominant model by evolving the capacity to obtain some or all of their carbon (and nutrients) from their plant hosts. The consequence of this evolution to parasitism is a relaxation of the evolutionary constraints associated with the need to maintain photosynthetic function, the very function that drove early stages of the ancient symbiotic relationship that produced the contemporary chloroplast. Extreme examples of reductionism among parasitic angiosperms reveals major alterations in chloroplast function with the loss of photosynthetic capacity and, with that, massive alterations in chloroplast genome content. This review highlights emerging patterns in reported gene loss and gene retention in the chloroplast genomes of parasitic plants. Some gene losses appear to occur in the early stages of parasitic evolution, even before the loss of photosynthetic capacity, like the chlororespiratory (ndh) genes. This contrasts with unexpected gene retentions, like that of the rbcL gene responsible for photosynthetic carbon dioxide fixation, and belies current understanding of gene function. The review relates gene retention to current knowledge of protein function and gene processing that has implications to broader aspects of genome conservation in organelles.

Biological Evolution↗
PubMed2000

Chapecoderins A-C, new labdane-derived diterpenoids from Echinodorus macrophyllus.

A new seco-labdane-type diterpenoid, chapecoderin A (1), and two new rearranged labdane-type diterpenoids, chapecoderins B (2) and C (3), were isolated from the leaves of the Brazilian medicinal plant Echinodorus macrophyllus ("Chapéu-de-couro"), and their structures and relative stereochemistry were elucidated by spectroscopic data. Chapecoderins A-C (1-3) possess in common an alpha,beta-unsaturated gamma-lactone ring in the side chain.

Molecular Structure↗
PubMed2007

Functional biology of plant phosphate uptake at root and mycorrhiza interfaces.

Phosphorus (P) is an essential plant nutrient and one of the most limiting in natural habitats as well as in agricultural production world-wide. The control of P acquisition efficiency and its subsequent uptake and translocation in vascular plants is complex. The physiological role of key cellular structures in plant P uptake and underlying molecular mechanisms are discussed in this review, with emphasis on phosphate transport across the cellular membrane at the root and arbuscular-mycorrhizal (AM) interfaces. The tools of molecular genetics have facilitated novel approaches and provided one of the major driving forces in the investigation of the basic transport mechanisms underlying plant P nutrition. Genetic engineering holds the potential to modify the system in a targeted way at the root-soil or AM symbiotic interface. Such approaches should assist in the breeding of crop plants that exhibit improved P acquisition efficiency and thus require lower inputs of P fertilizer for optimal growth. Whether engineering of P transport systems can contribute to enhanced P uptake will be discussed.

Biological Transport↗