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Neoplastic lesions were induced in 10 out of 58 experimental toads (Bufo regularis) force-fed with alpha-ecdysone, which naturally occurs in the leaves of bracken fern (Pteris aquilina). The results of this study prove that alpha-ecdysone may be one of the factors responsible for the carcinogenicity of bracken fern plant fed to cattle and other experimental animals.
Survival curves were constructed and D0 values determined after X-irradiation of single-celled germinating spores of 14 species of ferns, which had a wide variation in interphase chromosome and nuclear volumes and in DNA content per chromosome and per nucleus. A good fit to a line of slope equal to -1 is given on a log-log plot relating D0 to interphase chromosome volume. In a previous publication (Sparrow, Underbrink and Sparrow 1967), ferns fell into radiotaxon VIII, but the new data suggest that they should be assigned to a new group (VIIa) falling midway between radiotaxa VII and VIII. The calculated energy absorption per chromosome at D0 for VIIa is also intermediate between those for VII and VIII. If the value of this parameter is set at 1 for radiotaxon V, that for VIIa is approximately 32 times greater and the radiotaxa V, VI, VII and VIIa form a series 1 : 4 : 14 : 32. The new results indicate that radiotaxon VIII may have to be abandoned unless some other radiobiologically unexplored group (e.g. algae) fills the gap.
Field and greenhouse experiments were performed to assess the performance of phytoremediation of arsenic and lead from contaminated soil at an EPA Superfund site (Barber Orchard). Chinese Brake ferns (Pteris vittata) were used to extract arsenic. On average, fern shoot arsenic concentrations were as high as 20 times the soil arsenic concentrations under field conditions. It was estimated that 8 years would be required to reduce the acid-extractable portion of soil arsenic to safe levels (40 mg/kg). The effect of soil pH on arsenic extraction was also investigated. Results indicate that increasing soil pH may improve arsenic removal. Indian mustard plants (Brassica juncea) were used under greenhouse conditions to phytoextract soil lead. EDTA was applied to soil and was found to improve lead extraction. When the EDTA concentration was 10 mmol EDTA/kg soil in soil containing 338 mg Pb/kg soil, mustard plants extracted approximately 32 mg of lead. In conclusion, phytoremediation would be a suitable alternative to conventional remediation techniques, especially for soils that do not require immediate remediation.
The goals of this study were to test the hypothesis that plasticity of life history traits is greater among species with broad ecological distributions than among species with narrow ecological distributions and to determine whether homosporous filicalean fern gametophytes exhibit adaptively meaningful responses to soil substrates. Sporophyte populations of Asplenium platyneuron and Polystichum acrostichoides have broader ecological distributions and were therefore expected to exhibit a greater amount of gametophytic plasticity than either Asplenium rhizophyllum or Diplazium pycnocarpon. Changes in reproductive effort (i.e., gametangia mm-2) were investigated across the four following soil treatments, which represent major edaphic environments on which sporophyte populations of these species occur: stream bank, Pinus strobus canopy, oak forest ridge top, and soil from a lime-bearing rock outcrop. Our results failed to support the "ecological breadth" hypothesis. Three of the four species-A. rhizophyllum, D. pycnocarpon, and P. acrostichoides-exhibited similar amounts and directions of plasticity, with reproductive effort greatest in treatments that were unfavorable to growth; A. platyneuron exhibited the least amount of plasticity. Nevertheless, species-specific patterns in gametophytic size and reproductive effort reflected the distributions of their sporophytic counterparts. Plasticity of size-related reproductive effort may be common among homosporous filicalean fern gametophytes because of their short life spans and limited capacity for vegetative competition.
Numerous anatomically preserved fragments of the Middle Pennsylvanian age filicalean fern, Botryopteris tridentata, occur in coal balls collected at the Pittsburgh and Midway Coal Company mine near Baxter Springs, Kansas. Included are the first fertile specimens of the species, evidence of complete vegetative frond architecture, and fronds that are specialized for vegetative propagation. Rhizomes are erect and unbranched, have helical phyllotaxis and short internodes, and typically display an ectophloic solenostele. Fronds are tripinnately compound with lobed pinnules that have open, dichotomous venation. Fertile pinnae or individual pinnules are interspersed among vegetative frond segments and produce sori of annulate sporangia beneath veins on the abaxial pinnule surface. Fertile pinnule lobes are rolled toward the abaxial surface to enclose the sori. Sporangia have a horizontally elongated biseriate annulus located near the short broad stalk and produce tetrahedral-shaped trilete spores with coarse spines. Epiphyllous branches diverge from the stipe or rachis, and some fronds produce only branches. This fern is reconstructed as having short stems. Helically arranged fronds are either pinnately dissected with lobed vegetative pinnules and abaxially rolled fertile pinnules or are specialized for vegetative propagation. The latter functioned as the foliar equivalent of stolons. While some characters of the B. tridentata plant are similar to those of Botryopteris forensis, generitype of the Botryopteridaceae, others are more comparable to those of Psalixochlaena cylindrica, generitype of Psalixochlaenaceae, suggesting the need for reevaluation of systematic relationships among species of the Botryopteridaceae and Psalixochlaenaceae.
A new approach to fern-like structures in dried ovulatory cervical mucus has been carried out. Polarizing microscopy and conventional X-ray devices permitted these well-known structures to be demonstrated as being, both in nature and structure, more complex than previously described. The core of the dendrites appears to be mainly composed of NaCl, but also of KCl. They appear, under the polarizing microscope, as isotropic crystals. Anisotropic structures can be observed either at the periphery of the dendrites or isolated as small spheroliths. Anisotropic structures are insensitive to temperature variations but highly hygroscopic. They become rapidly amorphous when placed at room temperature without caution. The anisotropic period, 7 days long, is inscribed within the ferning period. Maximum anisotropy corresponds to the maximum production of cervical mucus, spinability value and basal body temperature rise. Anisotropic structures may be considered to be characteristic structures occurring spontaneously in ovulatory cervical mucus. These newly described structures consist of sodium or potassium sulphates.
Gametophytes of the fern Adiantum capillus-veneris L. were mutagenized by heavy ion beam irradiation and screened for mutants lacking chloroplast avoidance movement under high intensity blue light. Mutants recovered include several with small deletions in the AcPHOT2 gene. The avoidance movement response in these mutants could be restored by transient expression of non-mutant AcPHOT2 cDNA, indicating that the chloroplast avoidance movement in this fern is mediated by the Acphot2 protein. Further functional analyses of the Acphot2 protein were performed using this transient assay for chloroplast avoidance movement. The results obtained suggest that the LOV2, but not the LOV1, domain of Acphot2 is essential for avoidance movement, and that several residues in the C-terminus of the kinase domain contribute to the avoidance response. The rate of dark reversion of the photo-activated LOV2 domain, which was calculated photometrically, was too fast to account for the lifetime of phot2 signal estimated from physiological responses. However, the rate of dark reversion of the combined domains of LOV1 and LOV2 did correspond to the lifetime of the signal, suggesting that LOV1 might have some function in this response, although it is not essential for playing a role as a photoreceptor.
The phytochrome gene (PHY1) cDNA from the fern Adiantum capillus-veneris encodes an amino acid sequence that shows equal similarity (50-60%) to all five Arabidopsis phytochromes (PHYA-E). The A. capillus-veneris PHY1 cDNA was transformed into Arabidopsis ecotype Landsberg erecta to investigate its activity in angiosperms. Three of the resulting lines contained at least 8 times more spectrally active phytochrome than the wild type, indicating that A. capillus-veneris phytochrome can incorporate the chromophore of the host plants. Hypocotyl growth inhibition of these transgenic lines was investigated under red and far-red light. The results indicated dominant negative activity of A. capillus-veneris phy1 on the phytochrome A response in the host plants under continuous far-red light. However, the fern phytochrome did not interfere with the red-light repression of hypocotyl growth mediated by endogenous phytochrome B, and it failed to complement a phyB mutant phenotype. These observations suggest that the phy1 phytochrome molecule is too diverged from those of Arabidopsis to be fully functional.
Excised juvenile leaves of Microgramma vacciniifolia (Polypodiaceae) develop sporophytic regenerants when grown on mineral agar with sucrose. The ratio of sporophytes to gametophytes produced from the leaf tissue increases with higher percentages of sucrose such that at 4% sucrose, the induction of aposporous gametophytes is a rare occurrence. Experiments varying the osmotic potential with sorbitol and those holding the osmotic potential of the culture medium constant while varying the sucrose level indicate that the effect of sucrose on the differentiation of fern leaf tissue into either gametophyte or sporophyte is nutritional rather than osmotic. A significant effect of sucrose in altering the differentiation of fern leaf tissue is the increased rate of senescence promoted by high sucrose concentrations.
The 2.2S spore storage protein (matteuccin) of the ostrich fern, Matteuccia struthiopteris, has been isolated and characterized. It is a small basic protein consisting of two disulfide-linked polypeptides with approximate molecular masses of 3.0 kDa and 8.0 kDa. At least four different isoforms exist where two of the forms differ from the other by having a slightly smaller heavy chain. Amino acid analysis reveals that the 2.2S protein is rich in arginine. Almost complete amino acid sequence information was obtained for the light chain and a partial sequence for the heavy chain. Amino acid sequence comparison reveals that this protein shows a high similarity to seed storage proteins in different angiosperm species in spite of the fact that the common ancestor of ferns and angiosperms lived more than 300 million years ago.
Phytochrome controls several developmental steps during formation and differentiation of the fern gametophyte, including spore germination, morphogenesis of the gametophyte or differentiation of the sexual cells. To obtain information about the amino acid sequence and the regulation of phytochrome expression at the gene level, two degenerated oligonucleotides against well conserved amino acid regions were designed after an optimal alignment of the known phytochrome sequences. These primers were tested against DNA isolated from Arabidopsis thaliana, and the polymerase-chain reaction (PCR) products were cloned and sequenced. The DNA fragment produced with this method proved to be identical with a phytochrome-A-gene fragment from A. thaliana, and hence this fragment was used in further experiments to prove whether amplified DNA from fern species contains phytochrome-like DNA. With this procedure we successfully detected and cloned gene fragments both from gametophytes of Anemia phyllitidis and Dryopteris filix-mas, cultured for 7 days under vegetative conditions. In addition, poly(A)+ RNA was prepared from 7-day-old gametophytes of A. phyllitidis, induced to differentiate antheridia under generative conditions. This poly(A)+ RNA was transcribed into complementary DNA and used together with both phytochrome specific primers in a PCR experiment. We thereby obtained another DNA fragment. These data strongly suggest that A. phyllitidis has at least two phytochrome genes, and that at least one of them is expressed in light-grown gametophytes.
The tear film was evaluated by the ferning test. We tested tear film in right and left eye on 28 subjects (total 56 eyes), of whom 14 were affected by Down's syndrome, age range 18 to 35 years. The results obtained show that there exists an alteration of the tear ferning in subjects affected by Down's syndrome. We did not find any difference between the right or left eye in each individual. This anomaly could be responsible for frequent infectious pathologies found in the anterior eye segment in these subjects.
Two filamentous, branched, and septate actinomycetes were isolated from field-collected and from axenic in vitro produced root nodules of Alnus crispa var. mollis Fern. host plant. After their transfer to a chemically defined medium, these nodule isolates could not be distinguished from each other on the basis of morphology, cultural reactions, and whole cell composition and were considered to be the same species. They were morphologically similar to the root nodule endophyte, but were incapable of nodulating aseptic host plants growing in a nitrogen-deficient substrate. Whole cells of the nodule isolates were used for the production of rabbit antibodies. The resulting specific antiisolate antibodies were conjugated with fluorescein isothiocyanate and used in staining tests of the nodule endophyte. The immunofluorescence reactions demonstrated the homology of the nodule isolates with the nodule endophyte. After pectinase degradation of the endophyte capsule, the indirect immunoferritin method corroborated the fluorescent anti-body (FA) staining reactions. There was no antigenic relationship between the nodule isolates and 13 known strains of actinomycetes as determined by the FA techique. Fluorescent antibody reactions of adsorbed conjugates suggested that endophytes of both Alnus crispa var. mollis Fern. and Alnus rugosa (DuRoi) Spreng. root nodules belong to a common serotype. The LL and mesoisomers of diaminopimelic acid were present in similar proportions in the nodule endophyte and in the nodule isolates. Glucose, mannose, and an unknown sugar were the predominant whole cell sugars in the nodule isolates, although trace amounts of arabinose and rhamnose were also displayed. The unknown sugar found in the nodule isolates was also present in trace amounts in the endophyte-suspension hydrolysate.
Neoplasms developed in 18 of 98 toads, Bufo regularis, subjected to enforced feeding with bracken fern. They comprise 7 cases of adenocarcinoma in the ileum, 16 cases of hepatomas in the liver and 6 cases of neoplasms in the kidney due to metastases from the hepatomas. The results demonstrate that the Egyptian toad can be considered as an advantageous model for detecting the carcinogenicity of bracken fern, since the lesions occur faster than in other experimental animals.
The ferning test can be regarded as a crystallization process obtained by simple water subtraction. Such a process is feasible for every kind of ocular fluid (i.e. tears and aqueous, vitreous and subretinal fluids). The ferning test can be described in terms of fractal geometry, as the image characteristics related to this test are consistent with three of the main properties of fractals: self-similarity, fractal dimension and lacunarity.
Megasporogenesis in the heterosporous fern Marsilea (Hydropterideae) shows features intermediate between sporogenesis in homosporous ferns and that in heterosporous seed plants. The plastids in the dyads and young spores were associated with tubules 30-35 nm in diameter, probably a specialized form of endoplasmic reticulum. No consistent differences in size or cytoplasmic components could be found between the megaspores of a tetrad that might account for differential survival. The view that megaspore viability within the tetrad is genetically determined is thereby strengthened.
Two new migrated hopane triterpenoids, viz. 4alpha-hydroxyfilican-3-one and fern-9(11)-en-12beta-ol, and olean-18-en-3-one and olean-12-en-3-one as the first example of oleanane compounds from Adiantum ferns were isolated along with many other known triterpenoids from Adiantum capillus-veneris of China and Egypt. Their structures were elucidated by spectroscopic analyses.
The utility of fluorescence microscopy for studying development of fern spores is investigated. Changes in the fluorescence characteristics during the developmental stages of fern sporangia can be attributed to the changes in the chemical composition of the cell wall. Bright blue autofluorescence of the spores indicated the presence of sporopollenin. The sporangial walls and the spores autofluoresced yellow under blue light excitation. Fluorescence microscopy is a useful addition to light, scanning, and transmission electron microscopy because living specimens can be studied owing to their fluorescence properties.