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PubMed2006

Introduction of the factor of partitioning in the lithogenic enrichment factors of trace element bioaccumulation in plant tissues.

Bioindicators are widely used in the study of trace elements inputs into the environment and great efforts have been conducted to separate atmospheric from soil borne inputs on biomass accumulation. Many monitoring studies of trace element pollution take into account the dust particles located in the plant surface plus the contents of the plant tissues. However, it is usually only the trace element content in the plant tissues that is relevant on plant health. Enrichment factor equations take into account the trace element enrichment of biomasses with respect soil or bedrocks by comparing the ratios of the trace element in question to a lithogenic element, usually Al. However, the enrichment equations currently in use are inadequate because they do not take into account the fact that Al (or whichever reference element) and the element in question may have different solubility-absorption-retention levels depending on the rock and soil types involved. This constrain will become critical when results from different sites are compared and so in this article we propose that the solubility factors of each element are taken into account in order to overcome this constrain. We analysed Sb, Co, Ni, Cr, Pb, Cd, Mn, V, Zn, Cu, As, Hg, and Al concentration in different zones of Catalonia (NE Spain) using the evergreen oak Quercus ilex and the moss Hypnum cupressiforme as target species. We compared the results obtained in rural and non industrial areas with those from the Barcelona Metropolitan Area. We observed differences in Al concentrations of soils and bedrocks at each different site, together with the differences in solubility between Al and the element in question, and a weak correlation between total soil content and water extract content through different sites for most trace elements. All these findings show the unsuitability of the current enrichment factors for calculating lithospheric and atmospheric contributions to trace element concentrations in biomass tissues. The trace element enrichment factors were calculated by subtracting the part predicted by substrate composition (deduced from water extracts from soils and bedrock) from total concentrations. Results showed that for most of the trace elements analysed, trace elements enrichment factors were higher inside the Barcelona Metropolitan Area than outside, a finding that indicates that greater atmospheric inputs occur in urban areas. The results show that the most useful and correct way of establishing a reference for lithospheric and atmospheric inputs into the plant tissues is, first, to analyse samples of the same plant species collected from a number of sites possessing similar environmental conditions (climate, vegetation type, soil type) and, second, to use this new enrichment factor obtained by subtracting from the total concentration in plant tissue the predicted contribution of soil or bedrock extracts instead of that of total soil or bedrock concentrations.

Biomass↗
PubMed2004

Germin-like protein gene family of a moss, Physcomitrella patens, phylogenetically falls into two characteristic new clades.

We identified 77 EST clones encoding germin-like proteins (GLPs) from a moss, Physcomitrella patens in a database search. These Physcomitrella GLPs ( PpGLP s) were separated into seven groups based on DNA sequence homology. Phylogenetic analysis showed that these groups were divided into two novel clades clearly distinguishable from higher plant germins and GLPs, named bryophyte subfamilies 1 and 2. PpGLPs belonging to bryophyte subfamilies 1 lacked two cysteines at the conserved positions observed in higher plant germins or GLPs. PpGLPs belonging to bryophyte subfamily 2 contained two cysteines as observed in higher plant germins and GLPs. In bryophyte subfamily 1, 12 amino acids, in which one of two cysteines is included, were deleted between boxes A and B. Further, we determined the genomic structure of all of seven PpGLP genes. The sequences of PpGLP s of bryophyte subfamily 1 contained one or two introns, whereas those of bryophyte subfamily 2 contained no introns. Other GLPs from bryophytes, a liverwort GLP from Marchantia polymorpha , and two moss GLPs from Barbula unguiculata and Ceratodon purpureus also fell into bryophyte subfamily 1 and bryophyte subfamily 2, respectively. No higher plant germins and GLPs were grouped into the bryophyte subfamilies 1 and 2 by our analysis. Moreover, we revealed that PpGLP6 had manganese-containing extracellular superoxide dismutase activity. These results indicated that bryophyte possess characteristic GLPs, which phylogenetically are clearly distinguishable from higher plant GLPs.

Amino Acid Sequence↗
PubMed2005

Controlled expression of recombinant proteins in Physcomitrella patens by a conditional heat-shock promoter: a tool for plant research and biotechnology.

The ability to express tightly controlled amounts of endogenous and recombinant proteins in plant cells is an essential tool for research and biotechnology. Here, the inducibility of the soybean heat-shock Gmhsp17.3B promoter was addressed in the moss Physcomitrella patens, using beta-glucuronidase (GUS) and an F-actin marker (GFP-talin) as reporter proteins. In stably transformed moss lines, Gmhsp17.3B-driven GUS expression was extremely low at 25 degrees C. In contrast, a short non-damaging heat-treatment at 38 degrees C rapidly induced reporter expression over three orders of magnitude, enabling GUS accumulation and the labelling of F-actin cytoskeleton in all cell types and tissues. Induction levels were tightly proportional to the temperature and duration of the heat treatment, allowing fine-tuning of protein expression. Repeated heating/cooling cycles led to the massive GUS accumulation, up to 2.3% of the total soluble proteins. The anti-inflammatory drug acetyl salicylic acid (ASA) and the membrane-fluidiser benzyl alcohol (BA) also induced GUS expression at 25 degrees C, allowing the production of recombinant proteins without heat-treatment. The Gmhsp17.3B promoter thus provides a reliable versatile conditional promoter for the controlled expression of recombinant proteins in the moss P. patens.

Aspirin↗
PubMed2005

The evolution of the abscisic acid-response in land plants: comparative analysis of group 1 LEA gene expression in moss and cereals.

The moss Physcomitrella patens possesses a single copy of a Group 1 LEA gene, designated PpLEA-1. Sequence analysis of the PpLEA-1 gene reveals the gene to contain a single intron in a position conserved in all members of the Group 1 LEA gene family, but also to contain a premature termination codon within the first exon. Nevertheless, a PpLEA-1 transcript accumulates in moss tissues in response both to the imposition of osmotic stress, and to the plant growth regulator abscisic acid (ABA). This response appears to be mediated at the transcriptional level, and observation of the pattern of gene expression, reported by histochemical staining of plants expressing a PpLea-1::GUS transgene suggests that the promoter responds preferentially to ABA in protonemal filaments, whereas osmotic stress induces gene expression primarily in the gametophores. Quantitative analysis of promoter activity by transient expression in Physcomitrella protoplasts shows the PpLEA-1 promoter to be highly active in response to ABA and osmotic stress. ABA-mediated transgene expression from the PpLea-1 promoter occurs at a level similar to that driven by the highly active promoter of the wheat Group 1 LEA gene, E(m). Site-directed mutagenesis of the PpLEA-1 promoter indicates that ABA-inducibility is mediated via an ACGT-core motif similar to that seen in the ABA response elements of higher plant LEA genes. However, whereas the wheat E(m )promoter is active in moss tissues, the moss promoter is not reciprocally active in cereal cells: no activity, ABA-inducible or otherwise was detected in barley aleurone protoplasts transfected with the PpLEA-1::GUS construct. We propose that ABA activation of gene expression in moss cells represents an ancestral state, with only minimal requirements for promoter recognition, whereas cereal cells require the interaction of additional factors with ABA-responsive promoters.

Abscisic Acid↗
PubMed2006

Gene structure and expression pattern analysis of three monodehydroascorbate reductase (Mdhar) genes in Physcomitrella patens: implications for the evolution of the MDHAR family in plants.

The ascorbate-glutathione pathway plays a major role in the detoxification of reactive oxygen species (ROS) in vascular plants. One of the key enzymes in this pathway is monodehydroascorbate reductase (MDHAR), a FAD enzyme that catalyses the reduction of the monodehydroascorbate radical. To elucidate the evolution and functional role of MDHAR we identified and characterised MDHARs from the moss Physcomitrella patens. Expressed sequence tag (EST) databases containing approximately 100.000 ESTs from Physcomitrella were searched and three isoforms of monodehydroascorbate reductase (PpMDHAR1, PpMDHAR2 and PpMDHAR3) were identified. In vascular plants MDHAR is found in the cytosol, chloroplast, mitochondria and peroxisome. Surprisingly, all three PpMDHARs resembled the cytosolic isoforms from vascular plants lacking the NH(2)-terminal or COOH-terminal extension found in organelle targeted MDHARs. The number and position of introns was also conserved between PpMDHARs and cytosolic MDHARs from vascular plants. Phylogenetic analysis revealed that cytosolic MDHARs are monophyletic in origin and the ancestral gene evolved before the divergence of bryophytes more than 400 million years ago. Transcript analyses showed that expression of PpMdhar1 and PpMdhar3 was increased up to 5-fold under salt stress, osmotic stress or upon exposure to abscisic acid. In contrast, PpMdhar transcription levels were unchanged upon chilling, UV-B exposure or oxidative stress. The conservation of cytosolic MDHAR in the land-plant lineage and the transcriptional upregulation under water deficiency suggest that the evolution of cytosolic MDHAR played an essential role in stress protection for land plants when they inhabited the dry terrestrial environment.

Amino Acid Sequence↗
PubMed2006

The cellulose synthase (CESA) gene superfamily of the moss Physcomitrella patens.

The CESA gene superfamily of Arabidopsis and other seed plants comprises the CESA family, which encodes the catalytic subunits of cellulose synthase, and eight families of CESA-like (CSL) genes whose functions are largely unknown. The CSL genes have been proposed to encode processive beta-glycosyl transferases that synthesize noncellulosic cell wall polysaccharides. BLAST searches of EST and shotgun genomic sequences from the moss Physcomitrella patens (Hedw.) B.S.G. were used to identify genes with high similarity to vascular plant CESAs, CSLAs, CSLCs, and CSLDs. However, searches using Arabidopsis CSLBs, CSLEs, and CSLGs or rice CSLFs or CSLHs as queries identified no additional CESA superfamily members in P. patens, indicating that this moss lacks representatives of these families. Intron insertion sites are highly conserved between Arabidopsis and P. patens in all four shared gene families. However, phylogenetic analysis strongly supports independent diversification of the shared families in mosses and vascular plants. The lack of orthologs of vascular plant CESAs in the P. patens genome indicates that the divergence of mosses and vascular plants predated divergence and specialization of CESAs for primary and secondary cell wall syntheses and for distinct roles within the rosette terminal complexes. In contrast to Arabidopsis, the CSLD family is highly represented among P. patens ESTs. This is consistent with the proposed function of CSLDs in tip growth and the central role of tip growth in the development of the moss protonema.

Bryophyta↗
PubMed2005

Physcomitrella patens and Ceratodon purpureus, mosses as model organisms in photosynthesis studies.

With the discovery of targeted gene replacement, moss biology has been rapidly advancing over the last 10 years. This study demonstrates the usefulness of moss as a model organism for plant photosynthesis research. The two mosses examined in this study, Physcomitrella patens and Ceratodon purpureus, are easily cultured through vegetative propagation. Growth tests were conducted to determine carbon sources suitable for maintaining heterotrophic growth while photosynthesis was blocked. Photosynthetic parameters examined in these plants indicated that the photosynthetic activity of Ceratodon and Physcomitrella is more similar to vascular plants than cyanobacteria or green algae. Ceratodon plants grown heterotrophically appeared etiolated in that the plants were taller and plastids did not differentiate thylakoid membranes. After returning to the light, the plants developed green, photosynthetically active chloroplasts. Furthermore, UV-induced mutagenesis was used to show that photosynthesis-deficient mutant Ceratodon plants could be obtained. After screening approximately 1000 plants, we obtained a number of mutants, which could be arranged into the following categories: high fluorescence, low fluorescence, fast and slow fluorescence quenching, and fast and slow greening. Our results indicate that in vivo biophysical analysis of photosynthetic activity in the mosses can be carried out which makes both mosses useful for photosynthesis studies, and Ceratodon best sustains perturbations in photosynthetic activity.

Bryopsida↗
PubMed1984

Extended hopanoids in peat environments.

Detailed results are presented for the distributions of triterpenoid alkanes, acids and alcohols of the hopane family in ten samples of peat from three environments, and of contributing organisms in the case of Lyne of Skene, Scotland. Extended hopanoids of the beta alpha and alpha beta configuration appear at the very earliest stage of diagenesis. Such environments appear to be characterised by particular distributions of C32 hopanoid acids and alcohols, and a high preponderance of the C31 alpha beta hopane.

Acetates↗
PubMed1995

Marchantinquinone, isolated from Reboulia hemisphaerica, as inhibitor of lipid peroxidation and as free radical scavenger.

The antioxidant effect of marchantinquinone was studied using various models. Marchantinquinone inhibited Fe(2+)-induced lipid peroxidation in rat brain homogenate in a concentration-dependent manner with an IC50 15.3 +/- 2.9 microM. Marchantinquinone was less effective than alpha-tocopherol and BHT in reducing the stable free radical diphenyl-2-picrylhydrazyl (DPPH). The IC0.200 were 37.5 +/- 2.5, 9.2 +/- 1.6 and 14.5 +/- 2.5 microM, respectively. Marchantinquinone also scavenged peroxyl radical derived from 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH) in aqueous system with a stoichiometric factor of 0.9 +/- 0.1. Furthermore, it prevented conjugated-diene formation and apolipoprotein B (apo B) oxidation of LDL. However, marchantinquinone did not chelate Fe2+ or possess superoxide anion and hydroxyl radical scavenging activity. It also did not scavenge 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN)-derived peroxyl radical in hexane. These results indicate that marchantinquinone may be an effective antioxidant and can protect rat brain homogenate and LDL against oxidation.

Animals↗
PubMed1996

The German heavy metal survey by means of mosses.

This is the first attempt to determine pollution with metals throughout the Federal Republic of Germany by analysing moss samples. Samples of Pleurozium schreberi, Scleropodium purum, Hypnum cupessiforme and Hylocomium splendens were collected at 593 sites and analysed by ICP-AES and AAS for the elements As, Cd, Cr, Cu, Fe, Ni, Pb, V and Zn. Citrus leaves and pine needles were used as reference materials to ensure the quality of the results. In many cases it was possible to trace the areas affected by known sources of heavy-metal emissions in addition to isolated local increases in the values. The moss monitoring programme showed up the highly industrialized and urban locations such as the Ruhr, parts of the Saarland and Baden-Wurttemberg and large areas of eastern Germany. Lower levels of many elements were found in wide stretches of Lower Saxony and Bavaria. The results largely reflect the pollution patterns found in these areas. On the other hand, expected correlations between the effects of traffic (e.g. Pb) and concentrations in moss could not be demonstrated with certainty. The element data yielded by this project are Germany's contribution to the European project 'Atmospheric Heavy Metal Deposition in Europe -- Estimations based on Moss Analysis'.

Air Pollutants↗
PubMed1989

The genetic analysis of tropic responses.

An increasing number of studies on tropic responses includes the genetic analysis of mutants defective in these morphogenetic processes. This review collates the information and discusses the implications of this approach to such studies. The review is organized on a systematic basis because most genetic analyses are insufficiently complete for general principles to have emerged. The most advanced analyses are those of lower eukaryotes because of their haploidy and the ease with which they can be manipulated in vitro. The extensive studies of phototropism, gravitropism and autochemotropism in the fungus Phycomyces blakesleeanus and of phototropism, polarotropism and gravitropism in the moss Physcomitrella patens are reviewed. In comparison with these studies, the genetic analysis of tropic responses in particular species of flowering plants is more limited. However, comparative physiological and ultra-structural studies of individual mutant and wild-type strains have been performed for a number of species. These results are discussed with particular regard to their support for established hypotheses.

Bryopsida↗
PubMed1981

Optical and electron-microscopic studies of the Funaria hygrometrica protonema after cultivation for 96 days in space.

Funaria hygrometrica protonema cells grown in the "IFS-2" (Inoculating fixing system) for 96 days on board the Salyut 6-Soyuz 32 orbital scientific station were examined by light and electron-microscopy. Investigation of experimental and control cells of the moss protonema showed common features as well as distinctions in their structure. Protonema cells of Funaria hygrometrica both differentiate and undergo photosynthesis during space flight. Changes in cell shape, decreased cell size, a reduction in the volume of starch granules, and altered chloroplast structure were observed.

Bryopsida↗
PubMed1984

Long clinostation influence on the ultrastructure of Funaria hygrometrica moss protonema cells.

Changes in the ultrastructure of protonema cells of Funaria hygrometrica, cultivated during 20 days on a horizontal clinostat (2 rev/min), were determined by the electron microscopy method. About 20% of the cells were almost identical to those in the control, 20% were destructive cells, and in 60% ultrastructure changes were observed. The heterogeneity of the reaction demonstrated the evidence of sensitive cells on the clinostation process. Changes affected the ultrastructure of plastids, wall of the cell, and the form of the nucleus as well. Starch disappeared from chloroplasts practically completely, thylakoids swelled, granas frequently disappeared from plastids. Peroxisomes number in cells increased appreciably, width of cell walls decreased by almost half their size. Ca(++)-binding sites were revealed in cytoplasma of cells. Electronocytochemical exposure of ATPases activity with the presence of Mg++ and Ca++ ions showed that Mg(2+)-ATPase activity localization in clinosted cells was not too different from the control, while Ca(2+)-ATPase location presented differences in plasemalemma and Ca-sites. These changes are perhaps connected with the membranes permeability breaking and affect the plant cells adaptation to the influence of hypogravitation.

Bryopsida↗
PubMed1984

The role of calcium ions in cytological effects of hypogravity.

Electron-cytochemical and biochemical methods made it possible to reveal certain differences in ATPase activity stimulation by calcium ions in root apex cells of pea seedlings and moss protonema Funaria hygrometrica grown under stationary and slow clinostatic (2 rev/min) conditions. It was showed that under clinostatic conditions in comparison with the control variant the ATPase activity decreases in plasmalemma. The protein content in the plasmalemma fraction was also twice as low under these conditions. The root apex cells of the pea seedlings grown under spaceflight conditions were found to contain high concentrations of membrane-bound calcium. The data obtained are discussed in relation to problems of possible mechanisms of disturbance in calcium balance and the system of active calcium ion transport through plasmalemma under hypogravity.

Bryopsida↗
PubMed1989

Calcium gradient in plant cells with polarized growth in simulated microgravity.

Plant cells characterized by apical growth, for example, root hairs and apical cells of moss protonema, are a convenient model to address the problem of gravity response mechanisms including initiation of cell polarity. The fluorescent calcium probe, chlorotetracycline, allowed us to display the calcium distribution gradient in these cells. Irradiation by red light led to a sharp decrease in the Ca2+ ion activity in cells. During clinostatting in darkness the pattern of calcium influx and distribution changes inconsiderably as compared with control; in root hairs calcium is detected mainly in their apices and bases as in control. Addition of chlorpromazine to the medium probably increases the influx and accumulation of Ca2+ ions. Under data obtained confirm speculations on the Ca2+ ion functional role for the apical growth of plant cells and may suggest the participation of gravity in redistribution or activation of ion channels, calcium channels included, in the plasmalemma.

Bryopsida↗
PubMed1989

Long clinostation influence on the localization of free and weakly bound calcium in cell walls of Funaria hygrometrica moss protonema cells.

The pyroantimonate method was used to study the localization of free and weakly bound calcium in cells of moss protonema of Funaria hygrometrica Hedw. cultivated on a clinostat (2rev/min). Electroncytochemical study of control cells cultivated at 1 g revealed that granular precipitate marked chloroplasts, mitochondria, Golgi apparatus, lipid drops, nucleoplasma, nucleolus, nucleus membranes, cell walls and endoplasmic reticulum. In mitochondria the precipitate was revealed in stroma, in chloroplast it was found on thylakoids and envelope membranes. The cultivation of protonema on clinostat led to the intensification in cytochemical reaction product deposit. A considerable intensification of the reaction was noted in endomembranes, vacuoles, periplasmic space and cell walls. At the same time analysis of pectinase localization was made using the electroncytochemical method. A high reaction intensity in walls in comparison to that in control was found out to be a distinctive peculiarity of the cells cultivated on clinostat. It testifies to the fact that increasing of free calcium concentrations under conditions of clinostation is connected with pectinic substances hydrolysis and breaking of methoxy groups of pectins. Data obtained are discussed in relation to problems of possible mechanisms of disturbance in calcium balance of plant cells and the role of cell walls in gomeostasis of cell grown under conditions of simulated weightlessness.

Bryopsida↗
PubMed1992

The role of cellulases in the mechanism of changes of cell walls of Funaria hygrometrica moss protonema at clinostating.

Using electroncytochemical and biochemical methods, differences between the cytochemical reaction intensity and activity of the cellulosolytic enzymes in Funaria hygrometrica moss cells grown for 30 days in the horizontal clinostat (2 rev/min) and in control have been studied. It has been shown that on clinostating the precipitate amount and size increases with the cellulase activity enhancement in the periplasmic space and protonema cell walls, when compared to control. Using biochemical methods it has been found that the activity of both endo-1,4-beta-glucanase and exo-1,4-beta-glucanase was higher under these conditions. A decrease of cellulose total content, its crystalline form, and pectic substances as well as an increase of hemicellulose content have been revealed in the clinostated material compared to control. Data obtained are discussed regarding the possible mechanism of cellulase activation and synthesis inhibition and cellulose crystallization in plant cell walls at clinostating.

Bryopsida↗