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At least 127 records · Page 7Linked to original sources
PubMed1999

Phenylurea cytokinins assayed for induction of shoot buds in the moss Funaria hygrometrica.

The induction of shoot buds from the filamentous protonema of moss is a classic bioassay for cytokinin. While a large literature documents this response in many species of moss and for a wide range of natural and synthetic cytokinins, to date only substituted adenine cytokinins have been examined in detail. This paper shows that at least some of the novel phenylurea cytokinins will induce bud formation in mosses. Funaria responds to thidiazuron much as it responds to benzyladenine. Exposure to either substance results in log-linear dose-dependent increases in bud number that reach similar maximal numbers of buds at the optimal concentration of compound. The related compound chloro-pyridyl-phenylurea (CPPU) is slightly less active, but induces buds over a wider range of concentration. Carbanilide (diphenylurea or DPU), an active cytokinin in other systems, induces very few buds in Funaria, but does so over a wide range of concentration. Bioassay of mixtures of benzyladenine and DPU finds no evidence of competition for cytokinin receptors. That result could support suggestions that the phenylurea cytokinins act indirectly, by altering endogenous cytokinin metabolism, but we favor another interpretation. Unlike other cytokinin-responsive systems, the induction of buds from moss protonema involves two cytokinin-mediated events. The number of buds is controlled by the second cytokinin-mediated event. If DPU has little or no affinity for the receptor triggering this second event, DPU treatments will produce few to no buds, and kinetic analysis using bud number would find no evidence for competition with benzyladenine. Our results would support the hypothesis that bud induction in Funaria involves two chemically distinct cytokinin receptors.

Journal Article↗
PubMed2000

[Net photosynthetic rate of two species of wintering host mosses for gullaphids and its response to light, temperature and water content].

The net photosynthesis of Thuidium cymbifolium and Chrysocladium retrorsum, two species of wintering host mosses for gullaphids, and its response to light, temperature and water content were measured with CI-301PS(CID Inc. USA) both in winter and spring. The photosynthetic capacity of Thuidium cymbifolium and Chrysocladium retrorsum was about 141 and 117 mumolCO2kg-1dw.s-1, respectively, and trended to increase from winter to spring. The light saturation point of these two mosses at 800-900 mumol.m-2.s-1 was much higher than that of many other mosses, and the compensation point ranged from 40 to 50 mumol.m-2.s-1. The temperature response curves of these two mosses were similar, with optium temperature ranging from 25 to 36 degrees C in spring, and from 20 to 30 degrees C in winter. When the temperature was below the freezing point(-15 to 0 degree C), they both maintained a distinct net photosynthesis, with the optimum water content ranging from 200 to 300(400)% dw. The photosynthesis started to be restrained evidently, when the water content declined to about 150% dw. The gas exchange ceased or became negative, when the water content was as low as 40-50% dw. It can be inferred that these two species might be both poikilothermal and poikilohydric organisms, but the resistibility of T. cymbifolium to intense light and high temperature was higher than that of C. retrorsum.

Animals↗
PubMed2002

[Thoracolumbar fractures treated with Moss Miami system and anterior distraction device].

OBJECTIVE: To review our experience in treating thoracolumbar fractures with Moss Miami System and vertebra anterior distraction device(ADD). METHODS: Twenty-eight patients with thoracolumbar fractures admitted in the Department of Trauma and Reconstructive Surgery (Unfallkrankenhause, Berlin, Germany) were treated by posterior fixation with Moss Miami system and anterior decompression, followed by autologous bone grafting and ADD stabilizing implant. RESULTS: Death occurred in none of the cases and no patients exhibited signs of neurologic damages both intraoperatively and postoperatively, with the only exception that disruption of the dura mater of the spinal cord occurred in 1 case intraoperatively. Follow-up study lasting for a mean period of 11.8 months was conducted in all the cases, which found that the position of Moss Miami system and implanted ADD remained unchanged in 24 cases, in comparison with their position as shown by postoperative imaging data. In 3 cases, however, ADD was inlaid in the vertebral body, with an angle correction loss of which was less than 5 degrees. Lateral obliquity and displacement of ADD was found in 1 case. Of the 5 incomplete paraplegic patients, 3 achieved complete habilitation of neurologic function and 2 had partial improvement. CONCLUSION: Moss Miami system and ADD constitute good modalities in treating thoracolumbar fractures, with such merits as thorough decompression of the spinal canal, reliable fixation to allow early force loading with less correction loss of the angle, and are therefore suitable for treating unstable thoracolumbal fractures.

Adult↗
PubMed2003

A tribute to Senator Frank E. Moss. The father of hospice & home care.

Senator Frank E. Moss and Congressman Claude Pepper were the keynote speakers at the first National Association for Home Care & Hospice (NAHC) Annual Meeting, which took place in Atlanta in 1982. This was very appropriate because Senator Moss developed the first legislation to cover home health and hospice in Medicare. Together, he and Congressman Pepper played the lead role in bringing about the enactment of these provisions. Although many people gave the title to Congressman Pepper, he deferred to Senator Moss as the one person whose legislation and done the most to benefit older Americans. Senator Moss served as NAHC's senior counsel from 1982 until his death earlier this year. NAHC's 22nd Annual Meeting, which will take place in Orlando, Florida, this year will be the first gathering of the home care family he will miss in the past 21 years. What follows is a tribute and remembrance of the man known as the father of the modern home care and hospice movements.

Aged↗
PubMed1996

Tetracycline-regulated reporter gene expression in the moss Physcomitrella patens.

As ancestors of higher plants, mosses offer advantages as simple model organisms in studying complex processes such as development and signal transduction. Overexpression of transgenes after genetic transformation is a powerful technique in such studies. To establish a controllable expression system for this experimental approach we expressed a chimeric protein consisting of the Tn1O-encoded Tet repressor and the activation domain of Herpes simplex virion protein 16 in the moss Physcomitrella patens. We showed that this protein activates transcription from a suitable target promoter (Top 1O) containing seven operators upstream of a TATA box. In media containing very low levels of tetracycline (1 mg/l), expression levels of a beta-glucuronidase (GUS) reporter gene dropped to <1% of that in the absence of tetracycline. This regulation is due to interference of tetracycline with the DNA binding activity of the Tet repressor portion of the chimeric transcriptional activator. Stable transformants grown for three weeks on tetracycline-containing media showed negligible GUS activity, whereas GUS was expressed strongly within 24 h of transfer to tetracycline-free media. Potent and stringently regulated expression of other, physiologically active genes is thus readily available in the moss system using the convenient ToplO expression system.

Anti-Bacterial Agents↗
PubMed1994

Genome analysis of the moss Physcomitrella patens (Hedw.) B.S.G.

A wild-type (WT) strain of the moss Physcomitrella patens (Hedw.) B.S.G., two mutants derived from it (PC22 and P24), and a somatic hybrid, PC22(+)P24, were analysed. Staining of metaphases revealed 54 +/- 2 chromosomes in the somatic hybrid and 27 chromosomes in the wild type and the two mutants. Using flow cytometry (FCM), DNA contents were calculated to be 0.6 pg (WT, PC22), 1.2 pg (P24), and 1.6 pg (PC22(+)P24) per nucleus, respectively. Southern hybridization provided evidence for at least one family of highly repetitive DNA and, furthermore, revealed different amounts of repetitive DNA in the four genotypes. However, these sequences cannot account for the 100% increase in the nuclear DNA amount in mutant P24, relative to wild type. In FCM analyses every moss genotype generated just one single peak of fluorescence, indicating an arrest in the cell cycle during the daytime. Thermal denaturation of wild-type DNA revealed a G+C content of 34.6% for total DNA and 38.6% for plastid DNA. A cDNA library of 1.2 x 10(6) independent clones was established, from which sequences homologous to cab and rbcS, respectively, were isolated. These genes show significant homologies to those of higher plants, and, likewise, comprise multigene families. No restriction fragment length polymorphisms could be detected between the four moss genotypes using these cDNA probes.

Base Composition↗
PubMed1992

The plastome-encoded zfpA gene of a moss contains procaryotic as well as eucaryotic promoter consensus sequences and its RNA abundance is modulated by cytokinin.

Plastid DNA of the moss Physcomitrella patens has been sequenced. An open reading frame (ORF 315) was identified downstream from rbcL, between trnR-CCG and psaI. This ORF shares homology with zfpA, a putative regulatory gene in Pisum sativum. The moss ORF is preceded by a Shine-Dalgarno sequence, two plastid promoter consensus sequences, and three TATA boxes. A specific probe detected three transcripts of low abundance in the wild-type moss and a cytokinin-sensitive chloroplast mutant. Steady state levels of zfpA transcripts were different in the two genotypes. In mutant protonemata treated with cytokinin, steady state levels of the largest transcript decreased significantly.

Amino Acid Sequence↗
PubMed2003

Purification and characterization of a Ca(2+)-dependent/calmodulin-stimulated protein kinase from moss chloronema cells.

We have demonstrated the presence of a Ca2+-dependent/calmodulin-stimulated protein kinase (PK) in chloronema cells of the moss Funaria hygrometrica. The kinase, with a molecular mass of 70,000 daltons (PK70), was purified to homogeneity using ammonium sulphate fractionation, DEAE-cellulose chromatography, and calmodulin (CaM)-agarose affinity chromatography. The kinase activity was stimulated at a concentration of 50 mM free Ca2+, and was further enhanced 3-5-fold with exogenously added 3-1000 nm moss calmodulin (CaM). Autophosphorylation was also stimulated with Ca2+ and CaM. Under in vitro conditions, PK70 phosphorylated preferentially lysine-rich substrates such as HIIIS and HVS. This PK shares epitopes with the maize Ca2+-dependent/calmodulin-stimulated PK (CCaMK) and also exhibits biochemical properties similar to the maize, lily, and tobacco CCaMK. We have characterized it as a moss CCaMK.

Bryopsida↗
PubMed1996

Comparison of metal concentrations in three species of mosses and metal freights in bulk precipitations.

Concentration of 25 trace metals in mosses ( Hylocomium splendens, Pleurozium schreberi and Hypnum cupressiforme) are compared with bulk deposition freights (Bergerhoff method) at 3 sites in Switzerland, one on the plateau, a second in the northern prealps and a third in the southern alps. The three moss species are interchangeable and the atmospheric background deposition can be estimated with sufficient accuracy for Ag, Al, As, Cd, Ce, Co, Cr, Cu, Fe, Ga, Ge, La, Li, Mo, Nb, Ni, Pb, Th, Ti, U, V, W, Y, Zn. For Hg this study does not give definite results. No seasonal differences in moss concentrations from spring to autumn can be shown.

Journal Article↗
PubMed2003

Use of an inducible reporter gene system for the analysis of auxin distribution in the moss Physcomitrella patens.

The plant hormone auxin plays a major role in a variety of growth and developmental responses, even in the more ancient plants-for example, cell differentiation in mosses. Nevertheless, almost nothing is known about the distribution of auxin during moss development. To address this question, we characterised auxin distribution in the moss Physcomitrella patens using auxin-inducible reporter gene systems. Stable transgenic Physcomitrella plants were produced expressing the beta-glucuronidase (GUS) gene driven by the auxin-inducible promoters GH3 and DR5, respectively. Both fusions showed remarkable differences with respect to auxin-induced promoter strength and expression kinetics. A detailed characterisation of the GUS expression pattern in different developmental stages revealed that the highest auxin concentrations were in dividing and ontogenetic young cells.

Bryopsida↗
PubMed2005

Improved water retention links high species richness with increased productivity in arctic tundra moss communities.

A positive relationship between plant species richness and ecosystem functioning has been found in a number of experimental studies. Positive species interactions at high species numbers have been suggested as a cause, but mechanisms driving positive interactions have not often been tested. In this experiment we asked three questions: (1) What is the relationship between species richness and productivity in experimentally constructed moss communities? (2) Is this relationship affected by plant density? and (3) Can changes in moisture absorption and retention explain observed relationships? To answer these questions we exposed arctic tundra moss communities of different species richness levels (1-11 species) and two different densities in the greenhouse to two levels of drought (short and long). Biomass (by the community and individual species), height and community moisture absorption and retention were measured as response variables. High species diversity increased productivity (more so in low-density plots than in high-density plots), but only when plots were watered regularly. Plot moisture retention was improved at high species richness as well, and plant height and variation in height was increased compared to plants in monoculture. Under high-density and short-drought conditions 10 out of 12 species grew better in mixture than in monoculture, but under the long drought treatment only six species did. A positive feedback loop between biomass and improved humidity under high diversity was supported by path analysis. We conclude that in this community the relationship between species richness and productivity depends on moisture availability and density, with improved water absorption and retention likely to be the mechanism for increased plant growth when drought periods are short. Furthermore, since this is the opposite of what has been found for temperate moss communities, conclusions from one system cannot automatically be extrapolated to other systems.

Arctic Regions↗
PubMed1988

Atmospheric deposition of arsenic and selenium across Canada using Sphagnum moss as a biomonitor.

A biomonitoring study was made of the atmospheric deposition of arsenic and selenium across northern Canada utilizing Sphagnum fuscum moss. Intensive sampling was carried out adjacent to the smelter at Rouyn-Noranda, Quebec. An average background concentration of arsenic in the moss of 0.66 mg kg-1 was determined, while most selenium concentrations were below the detection limit of 0.2 mg kg-1. Elevated arsenic concentrations were found in the vicinity of the mining and smelting areas of Flin Flon, Manitoba, and Atikokan, Ontario. High concentrations of selenium were detected only near Rouyn-Noranda. Both arsenic and selenium occurred in moss at concentrations lower than found in Canadian soils.

Air Pollution↗
PubMed1986

Representativity of mosses as biomonitor organisms for the accumulation of environmental chemicals in plants and soils.

The suitability of mosses for air pollution monitoring of benzohexachloride isomers and polyaromatic hydrocarbons is shown by residue data of different samples from Europe. The interpretation of the results makes it obvious that next to regional pattern analysis, hypotheses for atmospheric transport and deposition processes of different environmental chemicals can also be formed. An evaluation of these kinds of bioindicator methods is presented by a quantitative comparison of air pollution data and accumulated residues in plants. The results indicate a high retention efficiency of mosses for pollutants dominantly adsorbed to particulate matter in the air, like polyaromatic hydrocarbons and heavy metals. The comparison of residue data of trace pollutants in mosses and other plants underlines the indicator functions of lower plants for air monitoring patterns with the exception of chlorinated hydrocarbons. They are more effective enriched by coniferous plants which contain ingredients able to absorb and transport these groups of environmental pollutants in the organism.

Air Pollutants↗
PubMed1992

Active biomonitoring of polycyclic aromatic hydrocarbons by means of mosses.

Spherical bags, packed with 20 g of peat moss (Sphagnum spp.), were exposed to ambient air at a distance of 1 km from a plant manufacturing electrodes for the production of aluminium, near Rotterdam, The Netherlands. In these bags, the concentrations of six polycyclic aromatic hydrocarbons were determined, and compared with the concentrations in moss bags that had been exposed in relatively clean areas. From the results it can be concluded that, in addition to their useful application for biomonitoring of heavy metals, mosses can be applied in active biomonitoring of polycyclic aromatic hydrocarbons in ambient air.

Journal Article↗
PubMed1995

Atmospheric trace element deposition: principal component analysis of ICP-MS data from moss samples.

Data from a Norwegian survey on atmospheric deposition, including 33 elements in 495 moss samples collected in 1990, are presented. The biomonitor moss used was Hylocomium splendens, and the analyses were carried out by ICP-MS. Principal component analysis is used to identify possible sources of the elements determined in the mosses. Dominant factors represent long-range atmospheric transported elements (Bi, Pb, Sb, Mo, Cd, V, As, Zn, Tl, Hg, Ga), windblown mineral particles (Y, La, Al, Li, U, Th, Ga, Fe, V, Cr), local emission sources (Ni, Cu, Co, and As; Zn, Cd, and Hg; Fe, Cr, and Al), transport from the marine environment (Mg, B, Na, Sr, Ca), and contribution from higher plants (Cs, Rb, Ba, Mn). Comparison of the results with similar surveys from 1977 and 1985 show a decreasing contribution of most long-range transported elements to southern Norway.

Journal Article↗
PubMed2006

Biosynthesis of C9-aldehydes in the moss Physcomitrella patens.

After wounding, the moss Physcomitrella patens emits fatty acid derived volatiles like octenal, octenols and (2E)-nonenal. Flowering plants produce nonenal from C18-fatty acids via lipoxygenase and hydroperoxide lyase reactions, but the moss exploits the C20 precursor arachidonic acid for the formation of these oxylipins. We describe the isolation of the first cDNA (PpHPL) encoding a hydroperoxide lyase from a lower eukaryotic organism. The physiological pathway allocation and characterization of a downstream enal-isomerase gives a new picture for the formation of fatty acid derived volatiles from lower plants. Expression of a fusion protein with a yellow fluorescent protein in moss protoplasts showed that PpHPL was found in clusters in membranes of plastids. PpHPL can be classified as an unspecific hydroperoxide lyase having a substrate preference for 9-hydroperoxides of C18-fatty acids but also the predominant substrate 12-hydroperoxy arachidonic acid is accepted. Feeding experiments using arachidonic acid show an increase in the 12-hydroperoxide being metabolized to C8-aldehydes/alcohols and (3Z)-nonenal, which is rapidly isomerized to (2E)-nonenal. PpHPL knock out lines failed to emit (2E)-nonenal while formation of C8-volatiles was not affected indicating that in contrast to flowering plants, PpHPL is only involved in formation of a specific subset of volatiles.

Aldehyde-Lyases↗
PubMed2005

Organochlorine pollutants in soils and mosses from Victoria Land (Antarctica).

The major organochlorine (OC) pollutants, i.e. pentachlorobenzene (PCBz), hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), polychlorobiphenyls (PCBs) and DDTs have been analyzed in soils and mosses from coastal areas of Victoria Land (70-80 degrees S, 160-170 degrees E). PCBs (23-34 ng g(-1) dry wt.) and PCBz (0.38-1.3 ng g(-1) dry wt.) were the dominant OCs in mosses and soils, respectively. In general, the concentrations of OC in soils, i.e. HCB (0.034-0.17 ng g(-1) dry wt.), PCBs (0.36-0.59 ng g(-1) dry wt.) and 4,4'-DDE (0.053-0.086 ng g(-1) dry wt.), range among the lowest reported in remote regions. These concentrations exhibited high correlation coefficients when represented vs. total organic carbon (TOC) which is consistent with the general correlation between OC and TOC in soils from remote areas recently observed (Meijer, S.N., Ockenden, W.A., Seetman, A., Breivik, K., Grimalt, J.O., Jones, K.C., 2003. Global distribution and budget of PCBs and HCB in background surface soils: implications for sources and environmental processes. Environ. Sci. Technol. 37, 667-672). Statistically significant dependences between reciprocal of temperature and log-transformed concentrations of HCB and 4,4'-DDE in mosses and alpha-HCH in soils have been found. These observations provide further data illustrating that temperature is a major factor determining the planetary scale distribution and accumulation of OCs giving additional ground to the general validity of the global distillation effect for description of planetary OC distribution.

Antarctic Regions↗
PubMed2005

Effects of altitude on element accumulation in alpine moss.

We determined trace metal concentrations in mature living tissues of the moss Hylocomium splendens, at different altitude, in the south-eastern Alps of Italy. We hypothesized that if precipitation does not vary with altitude trace element concentrations in moss tissues will not be affected by altitude. Contrary to our hypothesis, element concentrations did vary with altitude even in the absence of any precipitation pattern related to elevation. In particular, concentrations of anthropogenic pollutants (especially Cd and Pb) peaked at mid altitude (1400-1800 m) where frequency of cloud cover was the highest. We concluded that the trace metal concentrations in alpine mosses can be regarded as a reliable estimate of total atmospheric deposition, i.e., including occult deposition by cloudwater. The latter may account for a significant fraction of the total deposition of anthropogenic trace metals, in close relation to cloud cover frequency.

Air Pollutants↗