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PubMed2006

Comparison of elicitation potential of chloroatranol and atranol--2 allergens in oak moss absolute.

Chloroatranol and atranol are degradation products of chloroatranorin and atranorin, respectively, and have recently been identified as important contact allergens in the natural fragrance extract, oak moss absolute. Oak moss absolute is widely used in perfumery and is the cause of many cases of fragrance allergic contact dermatitis. Chloroatranol elicits reactions at very low levels of exposure. In oak moss absolute, chloroatranol and atranol are present together and both may contribute to the allergenicity and eliciting capacity of the natural extract. In this study, 10 eczema patients with known sensitization to chloroatranol and oak moss absolute were tested simultaneously to a serial dilution of chloroatranol and atranol in ethanol, in equimolar concentrations (0.0034-1072 microM). Dose-response curves were estimated and analysed by logistic regression. The estimated difference in elicitation potency of chloroatranol relative to atranol based on testing with equimolar concentrations was 217% (95% confidence interval 116-409%). Both substances elicited reactions at very low levels of exposure. It is concluded that the differences in elicitation capacity between the 2 substances are counterbalanced by exposure being greater to atranol than to chloroatranol and that both substances contribute to the clinical problems seen in oak moss absolute-sensitized individuals.

Adult↗
PubMed2005

Cloning and characterization of micro-RNAs from moss.

Micro-RNAs (miRNAs) are one class of endogenous tiny RNAs that play important regulatory roles in plant development and responses to external stimuli. To date, miRNAs have been cloned from higher plants such as Arabidopsis, rice and pumpkin, and there is limited information on their identity in lower plants including Bryophytes. Bryophytes are among the oldest groups of land plants among the earth's flora, and are important for our understanding of the transition to life on land. To identify miRNAs that might have played a role early in land plant evolution, we constructed a library of small RNAs from the juvenile gametophyte (protonema) of the moss Physcomitrella patens. Sequence analysis revealed five higher plant miRNA homologues, including three members of the miR319 family, previously shown to be involved in the regulation of leaf morphogenesis, and miR156, which has been suggested to regulate several members of the SQUAMOSA PROMOTER BINDING-LIKE (SPL) family in Arabidopsis. We have cloned PpSBP3, a moss SPL homologue that contains an miR156 complementary site, and demonstrated that its mRNA is cleaved within that site suggesting that it is an miR156 target in moss. Six additional candidate moss miRNAs were identified and shown to be expressed in the gametophyte, some of which were developmentally regulated or upregulated by auxin. Our observations suggest that miRNAs play important regulatory roles in mosses.

Base Sequence↗
PubMed2006

Novel micro-RNAs and intermediates of micro-RNA biogenesis from moss.

Micro-RNAs (miRNAs) are one class of small non-coding RNAs that have important regulatory roles in higher plants. Much less is known about their prevalence and function in lower land plants. Previously we cloned 100 non-structural small RNAs from the moss Physcomitrella patens but could annotate only 11 as miRNAs. To identify additional moss miRNAs among cloned small RNAs we have analyzed their genomic sequences for a characteristic miRNA precursor-like structure. This analysis revealed 19 new moss miRNAs that are predicted to be encoded by 22 putative foldbacks. Northern blot analysis confirmed the expression of 14 new miRNA representatives. Half of these were gametophore specific, the rest were detected at low levels in the protonema. We predicted 12 genes as targets of nine new miRNAs. Three of these show homology to transcription factors and the others appear to play roles in diverse physiological processes including light and cytokine signaling, which have not to date been shown to be regulated by a miRNA in flowering plants. Four target genes, which show homology to ATN1-like protein kinase, NAC transcription factors and a cytokinin receptor, have been validated by miRNA-mediated mRNA cleavage. In addition, our analysis revealed that seven small RNAs represent miRNA* and three represent intermediates of pre-miRNA processing, providing evidence for specific DICER-like cleavage steps during miRNA biogenesis in moss. Our findings suggest that miRNAs are common in mosses and set the stage for the elucidation of their varied biological functions.

Base Sequence↗
PubMed1999

Particle bombardment mediated transformation and GFP expression in the moss Physcomitrella patens.

There are few plants facilitated for the study of development, morphogenesis and gene expression at the cellular level. The moss Physcomitrella patens can be a very useful plant with several advantages: simple life cycle containing a major haploid gametophyte stage, easy manipulation, small genome size (6 x 10(8) bp) and high similarities with higher plants. To establish the transformation system of mosses as a model for basic plant research, a series of experiments were performed. Mosses were cultured in cellophane overlaid BCD media, transformed by particle bombardment and selected by the choice of appropriate antibiotics. Initial transformants appeared 8 d or 14 d after selection, showing different sensitivities toward the antibiotics used. Heat treatment during the preparation of particles revealed that denaturing the DNA enabled a more efficient way to deliver a transgene into the chromosome. This was proven by the increase in the number of transformants by five times in the plants with denatured DNA. In the test for the repairing capacity of mosses, 154 and 195 transformants survived from 1 d and 3 d incubations, respectively, indicating that a longer period of incubation seemed to be recommendable for better survival. The selected transformants were further analyzed at the DNA and expression level. Transformed genes were confirmed by PCR where all the transformants showed the expected size of amplification. Histochemical beta-glucuronidase (GUS) and green fluorescent protein (GFP) expression also confirmed the integration of exogenous DNA. In a comparison of the two different forms of GFP, soluble-modified GFP (smGFP) expressed stronger signals than modified GFP (mGFP) due to its improved solubility. Confirmation of the transgene in the chloroplast transformation has improved the applicability of moss as a model system for the study of basic biological researches.

Blotting, Southern↗
PubMed2001

[Photosynthetic characteristics of two plagiomnium mosses in summer and winter].

A comparative study on the photosynthetic characteristics of Plagiomnium acuium(Lindb.) T. Kop. and P. maximoviozii(Lindb.) T. Kp., two overwintering host mosses for Chinese gall aphid(Schlechtendalia chinensis), was conducted by using CI-301PS in Summer and Winter. The results showed that the photosynthetic capacity of these two mosses species was 125.67 and 94.63 mumol CO2.kg-1DW.s-1 in Summer, and 58.1 and 62.1 mumol CO2.kg-1DW.s-1 in Winter, respectively. The dark respiration rates of these two species in Summer significantly exceeded those in Winter. The light complementary point of these two mosses species was in the range from 20 to 40 mumol.m-2.s-1, and light saturated point was from 200 to 400 mumol.m-2.s-1, with higher value in Summer and lower value in Winter. Their apparent quantum yields were 1.535 and 1.559 in Summer, but only 0.456 and 0.459 in Winter. The optimum temperature for photosynthesis of these two mosses species was 20 to 35 degrees C, also higher in Summer and lower in Winter. No matter which species and growing season, the temperature coefficients(Q10) measured in the range of 0-20 degrees C were similar, ranging from 1.15 to 1.23. These two moss species could maintain a certain net photosynthesis for 10-30 minutes under temperature stress from -15 to -10 degrees C and from 40 to 45 degrees C.

Animals↗
PubMed2005

[Niche of the mosses on floor in Shanghai City].

The mosses on the floor of 22 sites at 20 main parks and 2 chemical plants in Shanghai were sampled, and 75 moss species were recorded. Their niche breadths were calculated by Levins equation. The results indicated that most moss species had rather narrow niche breadth, 68% of them with a niche breadth less than 0.1. The relationship between species number (N) and their niche breadth (B) followed the model N = 0.344 x e(-0.0377B), R = 0.9684. The niche overlaps of 39 main moss species (important value > 0.1) were calculated by Wang's equation. Based on their niche overlaps, the ordination plot of Principal Axes Analysis (PAA) and the Minimal Spanning Tree (MST) were drawn. The results showed that five ecological groups of the 39 moss species related to different habitats could be identified.

Bryophyta↗
PubMed2000

Testing morphological concepts of orders of pleurocarpous mosses (Bryophyta) using phylogenetic reconstructions based on TRNL-TRNF and RPS4 sequences.

The ordinal classification of pleurocarpous mosses rests on characters such as branching mode and architecture of the peristome teeth that line the mouth of the capsule. The Leucodontales comprise mainly epiphytic taxa, characterized by sympodial branching and reduced peristomes, whereas the Hypnales are primarily terricolous and monopodially branching. The third order, the Hookeriales, is defined by a unique architecture of the endostome. We sampled 78 exemplar taxa representing most families of these orders and sequenced two chloroplast loci, the trnL-trnF region and the rps4 gene, to test the monophyly and relationships of these orders of pleurocarpous mosses. Estimates of levels of saturation suggest that the trnL-trnF spacer and the third codon position of the rps4 gene have reached saturation, in at least the transitions. Analyses of the combined data set were performed under three optimality criteria with different sets of assumptions, such as excluding hypervariable positions, downweighting the most likely transformations, and indirect weighting of rps4 codon positions by including amino acid translations. Multiple parallelism in nonsynonymous mutations led to little or no improvement in various indices upon inclusion of amino acid sequences. Trees obtained under likelihood were significantly better under likelihood than the trees derived from the same matrix under parsimony. Our phylogenetic analyses suggest that (1) the pleurocarpous mosses, with the exception of the Cyrtopodaceae, form a monophyletic group which is here given formal recognition as the Hypnidae; (2) the Leucodontales are at least paraphyletic; and (3) the Hypnales form, with most members of the Leucodontalean grade, a monophyletic group sister to a Hookerialean lineage. The Hypopterygiaceae, Hookeriales, and a clade composed of Neorutenbergia, Pseudocryphaea, and Trachyloma likely represent a basal clade or grade within the Hypnidae. These results suggest that mode of branching and reduced peristomes are homoplastic at the ordinal level in pleurocarpous mosses.

Base Sequence↗
PubMed1993

Evidence for growth of Sporothrix schenckii on dead but not on living sphagnum moss.

When clinical isolates of Sporothrix schenckii were inoculated onto the apices of living or dead sphagnum moss plants maintained under growth chamber conditions, populations of the fungus, assessed by standard dilution plate methods, increased swiftly up to about 70-fold on moist, dead plants but did not increase on the live moss. Light and scanning electron microscopy revealed fungal growth and sporulation on and within dead plants, but no evidence of either on live plants. These data provide indirect support for the contention that S. schenckii does not grow on living sphagnum in bogs, but rather that sporotrichosis epidemics associated with sphagnum moss are likely to result from contamination of the dead plants at some point(s) in the chain of events during or after harvest. One practical implication of our results is that precautions should be taken to insure that sphagnum moss is stored dry and that it is not wetted any sooner than necessary before use. We also report here improvement of the Mycoses isolation medium by an increase in cycloheximide from 400 to 800 mg/l, chloramphenicol from 50 to 250 mg/l, and the addition of rifampicin at 20 mg/l.

Disease Reservoirs↗
PubMed2026

Diversification of Cellulose Synthase (CESA) Genes in Mosses Suggests Both Ancient and Recent Gene duplications.

Cellulose is an important polysaccharide that constitutes all plant cell walls, giving them strength and stability. The plant cellulose synthase (CESA) gene family, which encodes the catalytic subunits of cellulose synthesis complexes (CSCs), has diversified independently in several plant lineages, providing an interesting model for understanding selection for gene duplication. Here we quantified the presence of CESA genes across mosses to understand how the process of gene family diversification occurred in this group and how it parallels diversification in other groups. We first examined the CESA gene family in eight species of mosses across seven families for which whole genome assemblies were available. We then identified CESA genes from additional species, for which only short-read sequence data was available, by using BLAST searches and targeted gene assemblies. We validated this approach by comparing the assembled paralogs from the short-read data to the genes identified from whole genome assemblies in the eight reference species. This approach allowed us to identify paralogs directly from short-read data and greatly expand our sample set. Results from the combined empirical data support the hypothesis that CESA genes diversified within the moss lineage at least as early as the mesozoic period, during or possibly even prior to the onset of moss diversification, but also continue to diversify within modern species. In addition, we found evidence for purifying selection as the dominant force shaping these genes and observed that different lineages experienced different levels of evolutionary constraint. Lastly, our approach to assemble paralogs has the potential to allow researchers to improve analyses of gene duplication events.

Physcomitrium patens↗
PubMed1998

In Situ Investigation of Trace Metal Availability in Industrial Effluents Using Transplanted Aquatic Mosses

Three species of aquatic mosses, Rhynchostegium riparioides, Fontinalis antipyretica, and Cinclidotus danubicus, were collected from the same reference location and exposed in five industrial effluents. The purpose was to test their suitability for assessing trace metal contamination under adverse and contrasted environmental conditions. Two distinct experiments of 16 and 11 days were conducted. In spite of short residence times in the effluents, the bryophytes were considerably affected at several sites, showing a light green to yellowish color, brown-edged leaves, and even dead strands. Cinclidotus danubicus was the most resistant whereas Fontinalis antipyretica was the most sensitive species. The observed physiological damage had no obvious incidence on the accumulation capacity of the mosses. The biomonitors provided time-integrated patterns of trace metal bioavailability (copper, chromium, nickel, lead, and zinc) in the effluents with a clear discrimination between poorly, moderately, and heavily polluted sites. Compared to water analyses, these more reliable indications could be obtained with a considerably reduced sampling design. When substantial accumulation occurred in mosses, the highest concentrations were systematically found in Rhynchostegium riparioides and the lowest in Cinclidotus danubicus. As only quantitative, not qualitative, differences were observed, all investigated moss species can be recommended for the assessment of trace metals in effluents at their discharge into the natural environment.

Journal Article↗
PubMed2005

Gravitropic moss cells default to spiral growth on the clinostat and in microgravity during spaceflight.

In addition to shoots and roots, the gravity (g)-vector orients the growth of specialized cells such as the apical cell of dark-grown moss protonemata. Each apical cell of the moss Ceratodon purpureus senses the g-vector and adjusts polar growth accordingly producing entire cultures of upright protonemata (negative gravitropism). The effect of withdrawing a constant gravity stimulus on moss growth was studied on two NASA Space Shuttle (STS) missions as well as during clinostat rotation on earth. Cultures grown in microgravity (spaceflight) on the STS-87 mission exhibited two successive phases of non-random growth and patterning, a radial outgrowth followed by the formation of net clockwise spiral growth. Also, cultures pre-aligned by unilateral light developed clockwise hooks during the subsequent dark period. The second spaceflight experiment flew on STS-107 which disintegrated during its descent on 1 February 2003. However, most of the moss experimental hardware was recovered on the ground, and most cultures, which had been chemically fixed during spaceflight, were retrieved. Almost all intact STS-107 cultures displayed strong spiral growth. Non-random culture growth including clockwise spiral growth was also observed after clinostat rotation. Together these data demonstrate the existence of default non-random growth patterns that develop at a population level in microgravity, a response that must normally be overridden and masked by a constant g-vector on earth.

Bryopsida↗
PubMed2001

Mosses share mitochondrial group II introns with flowering plants, not with liverworts.

Extant bryophytes are regarded as the closest living relatives of the first land plants, but relationships among the bryophyte classes (mosses, liverworts and hornworts) and between them and other embryophytes have remained unclear. We have recently found that plant mitochondrial genes with positionally stable introns are well suited for addressing questions of plant phylogeny at a deep level. To explore further data sets we have chosen to investigate the mitochondrial genes nad4 and nad7, which are particularly rich in intron sequences. Surprisingly, we find that in these genes mosses share three group II introns with flowering plants, but none with the liverwort Marchantia polymorpha or other liverworts investigated here. In mitochondria of Marchantia, nad7 is a pseudogene containing stop codons, but nad7 appears as a functional mitochondrial gene in mosses, including the isolated genus Takakia. We observe the necessity for strikingly frequent C-to-U RNA editing to reconstitute conserved codons in Takakia when compared to other mosses. The findings underline the great evolutionary distances among the bryophytes as the presumptive oldest division of land plants. A scenario involving differential intron gains from fungal sources in what are perhaps the two earliest diverging land plant lineages, liverworts and other embryophytes, is discussed. With their positionally stable introns, nad4 and nad7 represent novel marker genes that may permit a detailed phylogenetic resolution of early clades of land plants.

Amino Acid Sequence↗
PubMed2002

Predicting the impact of climatic warming on the carbon balance of the moss Sanionia uncinata on a maritime Antarctic island.

The effects of climatic factors, especially those of temperature, on the carbon balance of the moss Sanionia uncinata were examined on King George Island in the maritime Antarctic. Net photosynthesis (P(n)) and dark respiration rates of two colonies (A and B) were measured with a portable infrared gas analyzer. Colony A showed small P(n) compared with its dark respiration rates throughout the growing season. Colony B showed much higher net photosynthetic rates, but the dark respiration rates of the two colonies did not differ significantly. Net photosynthetic rate determined at light saturation was almost constant over a wide temperature range, from 5 degrees to 15 degrees C, while the dark respiration was strongly affected by temperature. To assess the impact of warming on the carbon balance of the moss, cumulative carbon gain of the moss was calculated using a simulation model for the main part of the growing season. The results suggest that climatic warming may cause a reduction of carbon gain in some relatively photosynthetically inactive moss colonies.

Journal Article↗
PubMed2006

A new approach to assess atmospheric nitrogen deposition by way of standardized exposition of mosses.

A standardized method of moss exposition for assessing variations in nitrogen deposition was tested in the western part of Germany. Six pleurocarpous moss species were transplanted to two sites differing in their deposition rates but being comparable as to their climatic conditions. The mosses were exposed in standardized containers over a period of 12 months; the focus of interest was the effect of N deposition on nitrogen content and on (15)N natural abundance (delta(15)N-values). Within the first nine months only trends could be observed. However, after one year all species tested showed significantly higher N concentrations at the highly polluted site. Besides, more negative delta(15)N-values possibly reflecting the higher ammonium input were detected at this site. Surprisingly, most of the plants though being kept in plastic containers without a favourable substratum did not show any conspicuous deficiency symptoms. The potential advantages of a standardized moss exposition for N monitoring purposes are discussed. It is concluded that the method presented here can yield significant results in particular if the number of testing sites is increased.

Atmosphere↗
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↗
PubMed1995

Metal biomonitoring with mosses: procedures for correcting for soil contamination.

Highly variable total concentrations of 15 elements have been found in five species of epigeic mosses growing in remote areas of Italy and in northern Victoria Land (continental Antarctica). It is very likely that soil particles entrapped in the mosses cause these high element concentration differences, thereby leading to inexact interpretations of baseline concentrations and of element distribution in different parts of mosses. A simple procedure for estimating more plausible background values that consists of subtracting the substratum contribution from raw concentrations of elements in mosses is reported. The normalization of total concentrations to the regional soil composition is also emphasized, in order to point out other possible metal sources.

Journal Article↗
PubMed2004

The moss bioreactor.

The production of recombinant proteins in moss bioreactors provides all of the benefits of molecular farming in plants but avoids many plant-specific disadvantages, such as the genetic instability of de-differentiated cells in suspension culture or the lack of containment during field production. Protein yields are in the same range as those of other cell-culture-based production systems. On top of this, the moss Physcomitrella patens is the only known plant that can be genetically modified by homologous recombination, allowing efficient targeted gene disruption. Thus, the major drawback of producing human proteins in plants, allergic reactions caused by plant-specific glycosylation, can be diminished by targeted knockout of the responsible genes in moss. Unlike all other plants, moss allows straightforward 'humanisation' of plant-derived pharmaceuticals.

Bioreactors↗
PubMed2004

Active biomonitoring of element uptake with terrestrial mosses: a comparison of bulk and dry deposition.

Moss (Scleropodium purum) transplants were used to study bioconcentration originating from dry and bulk deposition, by measuring the tissue contents of Al, As, Ca, Cu, Fe, Hg, Mn, Ni, Pb, Se and Zn. Furthermore, a laboratory experiment was carried out to determine the sequence of maximum concentration and affinity of Al, Cu, Fe, Hg, Ni, Pb and Zn, in S. purum. We found that in many of the transplants, for the same period of exposure, higher levels of metals were accumulated via dry deposition than via bulk deposition. This result may be explained by the simple washing action of the rain on the surface of the moss, and by the existence of processes that provoke the loss of some of the accumulated elements: intercationic displacement and leaching caused by acid precipitation. Modelling of the final bioconcentration observed, as a balance of inputs and outputs of elements, revealed that this terrestrial moss does not integrate, but rather concentrates atmospheric deposition, and there exists a state of unstable equilibrium between inputs and outputs of elements, a state that is determined by the characteristics of the surrounding environment. On the basis of the results obtained in this study, we can conclude that at present, it is not possible to extrapolate the calibrations between the concentrations of elements accumulated in a certain species of moss to values of atmospheric deposition (bulk deposition) from one place to another with different environmental conditions.

Acid Rain↗