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At least 253 records · Page 14Linked to original sources

PubMed1999

Study on binding of REEs with water-soluble polysaccharides in fern.

The binding of rare earth elements (REEs) with water-soluble polysaccharides of nondeproteinization and deproteinization in the leaves of the fern Dicranopteris dichotoma was studied by molecular activation analysis (MAA). Two cold-water-soluble polysaccharides (extracted by 75% ethanol and 90% ethanol, respectively) and one hot-water-soluble polysaccharide (extracted by 90% ethanol) were separated using biochemical separation techniques. The eight rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb, and Lu) in these polysaccharides were determined by instrumental neutron activation analysis. Our new results showed that the REEs were bound firmly with the water-soluble polysaccharides in the plant, regardless of whether nondeproteinization or deproteinization was used. The molecular-weight (MW) measurement demonstrated that REEs were mainly bound with low-MW (10,000-20,000) polysaccharides.

Chromatography, Ion Exchange↗

PubMed1998

Isolation and characterization of homologues of plant blue-light photoreceptor (cryptochrome) genes from the fern Adiantum capillus-veneris.

Many blue-light mediated physiological responses have been studied in the fern Adiantum capillus-veneris. We have isolated genomic clones encoding sequences similar to those encoding blue-light photoreceptors (cryptochromes) in higher plants using the Arabidopsis CRY1 cDNA as a probe, and these positive clones fall into five independent groups. Using RACE procedures, we obtained full-length cDNA sequences for three of these five groups. The deduced amino acid sequences include the photolyase-homologous domain in the N-terminal half, and they also contain a C-terminal extension of about 200 amino acids in length. These structural features indicate that the genes indeed encode Adiantum cryptochromes and represent a small gene family having at least three members.

Amino Acid Sequence↗

PubMed2003

Electrophoretic evidence for homoeologous chromosome pairing in the apogamous fern species Dryopteris nipponensis (Dryopteridaceae).

Segregation of genotypes through homoeologous chromosome pairing in the apogamous species Dryopteris nipponensis was tested by electrophoretic analysis. Of 284 progeny examined (250 gametophytes and 34 sporophytes), from the parental sporophyte with the Pgi-2 genotype abc, five showed different genotypes from that of the parent (three aac, one bbc and one bcc). This is the first evidence for genetic segregation in the progeny of apogamous fern species.

Chromosome Pairing↗

PubMed2006

Negative phototropic response of rhizoid cells in the fern Adiantum capillus-veneris.

In general, phototropic responses in land plants are induced by blue light and mediated by blue light receptor phototropins. In many cryptogam plants including the fern Adiantum capillus-veneris, however, red as well as blue light effectively induces a positive phototropic response in protonemal cells. In A. capillus-veneris, the red light effect on the tropistic response is mediated by phytochrome 3 (phy3), a chimeric photoreceptor of phytochrome and full-length phototropin. Here, we report red and blue light-induced negative phototropism in A. capillus-veneris rhizoid cells. Mutants deficient for phy3 lacked red light-induced negative phototropism, indicating that under red light, phy3 mediates negative phototropism in rhizoid cells, contrasting with its role in regulating positive phototropism in protonemal cells. Mutants for phy3 were also partially deficient in rhizoid blue light-induced negative phototropism, suggesting that phy3, in conjunction with phototropins, redundantly mediates the blue light response.

Adiantum↗

PubMed2002

Cryptic species in the fern Ceratopteris thalictroides (L.) Brongn. (Parkeriaceae). I. Molecular analyses and crossing tests.

For the taxonomic revision of the problematic species Ceratopteris thalictroides, molecular analyses and crossing tests were conducted for 16 sources in the world. An analysis of allozyme composition of five enzymes revealed the presence of three intraspecific entities, which were called the south type, the north type, and the third type. An analysis of the nucleotide sequences of chloroplast DNA also distinguished the same entities. Crossing tests showed that the south type was completely cross-sterile with the other two types, and that the other two were considerably cross-sterile with each other. These results suggest that the three entities should be regarded as different biological species. Although the south type and the other two meet in several regions, complete cross-sterility between them seems to sustain their genetic distinctiveness in spite of occasional crossing. The results from the present study suggest that widely distributed fern species are apt to comprise several cryptic species.

Journal Article↗

PubMed1991

Effect of nomegestrol acetate on spinability, ferning and mesh dimension of midcycle cervical mucus.

A study was carried out in order to determine the impact of Nomegestrol acetate on the human cervix and to evaluate the ability of changes induced in cervical mucus to render the cervical canal hostile to spermatozoa at midcycle. Under the influence of Nom Ac, loss of spinability, absence of ferning pattern and drastic tightening of the glycoprotein meshwork rendered midcycle mucus very similar to that elaborated during physiological states under total progesterone dominance. The results obtained in this study gave clear evidence that Nomegestrol acetate may provide cervical blocking thereby preventing sperm transport to the uterine cavity.

Adult↗

PubMed1991

Ultrastructural and biochemical effects of cadmium on the aquatic fern Marsilea minuta Linn.

The uptake of cadmium by cultured vegetative clones of the aquatic fern Marsilea minuta was studied in a static experimental bioassay system as functions of dose and period of exposure. The pathomorphological manifestations of Cd toxicity, as studied by transmission electron microscope, indicated damage to chloroplasts and tonoplasts as well as electron opaque granular deposits. Preliminary evidence based on molecular sieving chromatography showed the formation of two cadmium-binding proteins of 78 and 33 kDa in the leaf tissue under cadmium stress.

Cadmium↗

PubMed1984

Separation of carcinogenic fraction of bracken fern.

Isolation of the carcinogen in the boiling water extract of bracken fern was conducted by following the active principle with a carcinogenicity bioassay. Fractionation of the bracken extract was carried out using adsorption on resin (Amberlite XAD-2 and TOYOPEARL HW-40 (c] and organic solvent extraction. A diet containing each of the fractions was given to 7 female Charles River Sprague-Dawley rats (CD rats) of 4 weeks old, except for the second fraction. All 7 rats given the last carcinogenic fraction developed mammary and intestinal tumors and 5 rats had urinary bladder tumors. Ptaquiloside (PT) which induced mammary cancer in female CD rats and rho-hydroxystyrene glycosides were isolated from this fraction.

Animals↗

PubMed1994

The fern Polypodium decumanum, used in the treatment of psoriasis, and its fatty acid constituents as inhibitors of leukotriene B4 formation.

The fern Polypodium decumanum, commonly called Calaguala, has a clinically documented use in South America and Spain in the treatment of psoriasis. One of the inflammatory mediators isolated in abnormally high quantities in the psoriatic skin is leukotriene B4 (LTB4). Calaguala was tested in an in vitro model using human leukocytes for its ability to inhibit the LTB4 formation. The inhibition was found to be caused by the polyunsaturated fatty acids (PUFAs) linoleic, linolenic and arachidonic acid. IC50 values were determined for the isolated acids and compared to a group of closely related acids also commonly found in nature. The IC50 values for most acids tested were of the same magnitude (20-60 microM) except for arachidonic acid which showed stimulatory activity and 8(R) hydroxylinoleic acid which gave 30% inhibition with the highest dose tested (120 microM). The amounts of PUFAs in different Calaguala extracts were quantitatively analysed and it is concluded that the fatty acid constituents of Calaguala may contribute to the clinical effects of the extract.

Chromatography, High Pressure Liquid↗

PubMed2005

Effects of arbuscular mycorrhizal inoculation on uranium and arsenic accumulation by Chinese brake fern (Pteris vittata L.) from a uranium mining-impacted soil.

A glasshouse experiment was conducted to investigate U and As accumulation by Chinese brake fern, Pteris vittata L., in association with different arbuscular mycorrhizal fungi (AMF) from a U and As contaminated soil. The soil used contains 111 mg U kg(-1) and 106 mg As kg(-1). P. vittata L. was inoculated with each of three AMF, Glomus mosseae, Glomus caledonium and Glomus intraradices. Two harvests were made during plant growth (two and three months after transplanting). Mycorrhizal colonization depressed plant growth particularly at the early stages. TF (transfer factor) values for As from soil to fronds were higher than 1.0, while those for roots were much lower. Despite the growth depressions, AM colonization had no effect on tissue As concentrations. Conversely, TF values for U were much higher for roots than for fronds, indicating that only very small fraction of U was translocated to fronds (less than 2%), regardless of mycorrhizal colonization. Mycorrhizal colonization significantly increased root U concentrations at both harvests. Root colonization with G. mosseae or G. intraradices led to an increase in TF values for U from 7 (non-inoculation control) to 14 at the first harvest. The highest U concentration of 1574 mg kg(-1) was recorded in roots colonized by G. mosseae at the second harvest. The results suggested that P. vittata in combination with appropriate AMF would play very important roles in bioremediation of contaminated environments characterized by a multi-pollution.

Arsenic↗

PubMed2004

Arsenic complexes in the arsenic hyperaccumulator Pteris vittata (Chinese brake fern).

Pteris vittata (Chinese brake fern), the first reported arsenic (As) hyperaccumulating plant, can be potentially applied in the phytoremediation As-contaminated sites. Understanding the mechanisms of As tolerance and detoxification in this plant is critical to further enhance its capability of As hyperaccumulation. In this study, an unknown As species, other than arsenite (AsIII) or arsenate (AsV) was found in leaflets by using anion-exchange chromatography-hydride generation-atomic fluorescence spectroscopy and size-exclusion chromatography-atomic fluorescence spectrometry. The chromatographic behavior of this unknown As species and its stability suggest that it is likely an As complex. Although phytochelatin with two subunits (PC2) was the only major thiol in P. vittata under As exposure, this unknown As complex was unlikely to be an AsIII-PC2 complex by comparison of their chromatographic behaviors, stability at different pHs and charge states. The complex is sensitive to temperature and metal ions, but relatively insensitive to pH. In buffer solution of pH 5.9, it is present in a neutral form.

Arsenicals↗

PubMed2004

Thiol synthesis and arsenic hyperaccumulation in Pteris vittata (Chinese brake fern).

Pteris vittata (Chinese brake fern) has potential for phytoremediation of As-contaminated sites. In this study, the synthesis of total thiols and acid-soluble thiols in P. vittata was investigated under arsenic exposure. The strong and positive correlation between As concentration and acid-soluble thiols in plant leaflets suggests that acid-soluble thiols may play a role in As detoxification. A major As-induced thiol was purified and characterized. A molecular ion (M + 1) of 540 m/z suggests that the thiol was a phytochelatin (PC) with two base units (PC(2)). However, the ratios of acid-soluble thiols to As in leaflets exposed to As ranged from 0.012 to 0.026, suggesting that only a very small part of As is complexed by PC(2). PCs could play a minor detoxification role in this hyperaccumulator. A PC-independent mechanism appears to be mainly involved in As tolerance, while PC-dependent detoxification seems to be a supplement.

Arsenic↗

PubMed1988

Localization of the active principles of the male fern (Dryopteris filix-mas (L.) Schott.) by fluorescence microscopy.

The active principles of the male fern, Dryopteris filix-mas (L.) Schott., consisting of a mixture of phloroglucinol derivatives called "crude filicin", are localized by means of fluorescence microscopy under U.V. 365 nm and monochromatic blue 435-490 nm lights. Crude filicin is autofluorescent, and therefore may be easily localized in the internal glandular hairs of the intercellular spaces of rhizome and leaf bases parenchyma, without pre-treatment of sections. Localization is confirmed both morphologically and chemically, and is possible on a fresh material, as well as on a desiccated one. The test allows also a complete anatomical examination of sections, and may be useful, for its easiness and quickness, in further taxonomic or pharmacognostic studies.

Butyrophenones↗

PubMed1997

An extract of the fern Polypodium leucotomos inhibits human peripheral blood mononuclear cells proliferation in vitro.

An alcoholic extract of the fern polypodium leucotomos (PLE) has been empirically used as an immunosuppressor for the treatment of several autoimmune diseases. In this paper, we investigated the effects of PLE on activation and proliferative responses of peripheral blood mononuclear cells (PBMNC) from healthy donors to T lymphocyte polyclonal mitogens. PLE shows a significant inhibitory effect on the proliferative response of PBMNC to stimulation with phytohaemagglutinin (PHA) or anti CD3 monoclonal antibodies (p < 0.05). In contrast, PLE did not modify the proliferative response of PBMNC to phorbol esters (p > 0.05). The inhibitory effect of PLE upon mitogen induced PBMNC proliferation is time dependent and can be overcome by the exogenous addition of interleukin-2 to the culture medium (p < 0.05). The decreased proliferative response of PBMNC to PHA stimulation in the presence of PLE is not associated with a significant modification of expression of the alpha chain (CD25) of the IL-2 receptor (p > 0.05). In conclusion, PLE shows an inhibitory effect on the polyclonal proliferative response of PBMNC to T lymphocyte mitogens that interact with cytoplasmic membrane molecules.

Adult↗

PubMed1998

Ptaquiloside Z, a new toxic unstable sesquiterpene glucoside from the neotropical bracken fern Pteridium aquilinum var. caudatum.

Reversed-phase HPLC fractionation, monitored by brine shrimp bioassay, led to the isolation of a new illudane-type sesquiterpene glucoside, ptaquiloside Z (2), as well as the known bracken carcinogen ptaquiloside (1), from a bioactive aqueous extract of the neotropical bracken fern Pteridium aquilinum var. caudatum (Pteridaceae). The structure of ptaquiloside Z (2) was confirmed by spectroscopic analyses and chemical degradation. Both compounds exhibited similar toxicity (LC50 62.5 micrograms/ml at 24 h and LC50 7.8 micrograms/ml at 48 h) toward brine shrimp.

Animals↗

PubMed2003

Photoprotective properties of a hydrophilic extract of the fern Polypodium leucotomos on human skin cells.

The effect of a hydrophilic extract of the fern Polypodium leucotomos (PLE) has been investigated in terms of photoprotection against UV-induced cell damage. PLE efficiently preserved human fibroblast survival and restored their proliferative capability when the cells were exposed to UVA light. This effect was specific and dose-dependent. Photoprotection was not restricted to fibroblasts, as demonstrated by its effect on survival and proliferation of the human keratinocyte cell line HaCat. Finally, treatment of the cells with PLE prevented UV-induced morphological changes in human fibroblasts, namely disorganisation of F-actin-based cytoskeletal structures, coalescence of the tubulin cytoskeleton and mislocalization of adhesion molecules such as cadherins and integrins. Our in vitro results demonstrate the photoprotective effect of PLE on human cells and support its use in the preventive treatment of sunburning and skin pathologies associated with UV-mediated damage.

Acetylcysteine↗

PubMed2002

Seasonal changes in polar lipids in fronds of the ferns Dryopteris filix-mas and Matteuccia struthiopteris.

The distribution pattern of total lipids, glyco- and phospholipids, and one betaine lipid (DGTS) in the fronds ofthe ferns Dryopteris filix-mas and Matteuccia struthiopteris was studied. The lipid composition of the embryo leaflets forming a bud, or "treble clef", and that of fully opened leaves changed throughout the growth season. The maximum amount of DGTS in clefs and mature leaves was detected at the beginning of the season. By midsummer, the DGTS content decreased, dropping to zero in the fully opened leaves, and then increased again. The amount of DGTS in the clefs collected in October versus those collected in May was somewhat higher in the case of Dryopteris filix-mas and almost twofold lower in the case of Matteuccia struthiopteris. The ratio between polar lipids contained in the clefs and mature leaves throughout the growth season was determined.

Betaine↗

PubMed1976

Thymidine phosphotransferase and nucleotide phosphohydrolase of the fern Asplenium nidus. General properties and inhibition by adenosine 3':5'-cyclic monophosphate.

1. Extracts of several plant species contained nucleoside-AMP phosphotransferase activity. The ratio of activity with thymidine to that with uridine as nucleoside substrate was essentially constant, both between species and throughout plant development. Evidence is presented that the total thymidine-AMP phosphotransferase activity of the leaves of Asplenium nidus (bird's-nest fern) and of Helianthus tuberosus (Jerusalem artichoke) increases during maturation. 2. Thymidine-AMP phosphotransferase was purified 22-fold from a very rich source of this activity, extracts of A. nidus. 3. A broad specificity towards both nucleoside and nucleoside 5'-monophosphate substrates is displayed by this preparation, and the evidence suggests that all could be due to a single enzyme. 4. Nucleosides that act as substrates will also inhibit phosphotransfer to other nucleosides, with Ki values close to the corresponding Km values found when utilized as substrates. 5. Ca2+-activated ATP phosphohydrolase was separated from the phosphotransferase by differential complexing to Blue Dextran in the presence of urea, whereas an AMP phosphohydrolase activity was closely associated with thymidine-AMP phosphotransferase through all separation techniques used. 6. Metal ions did not activate either of the latter two activities, and 1,10-phenanthroline was found to inhibit the phosphotransferase. 7. Km values for AMP for the respective activities were 0.11 mM (thymidine phosphotransferase) and 0.20 mM (AMP phosphohydrolase) and for thymidine (phosphotransferase only) 0.88 mM. 8. 3':5'-Cyclic AMP was found to inhibit both phosphotransferase and AMP phosphohydrolase activities, with Ki values of 0.056 mM and 0.15 mM respectively. It is suggested that this inhibitor would be of value in revealing the existence of thymidine kinase in plant extracts with high thymidine phosphotransferase activity.

Adenosine Monophosphate↗