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A new flavone glycoside isolated from the fern Pteris cretica has been shown to be luteolin 7-O-robinobioside (1) by chemical and spectral methods. In addition luteolin 7-O-rutinoside (2) and luteolin 7-O-glucoside (3) have been isolated from this plant. Flavonoid 2 is reported for the first time in ferns.
The polarity of germinating single-celled spores of the fern Ceratopteris richardii Brogn. is influenced by gravity during a time period prior to the first cellular division designated a "polarity-determination window". After this window closes, control of polarity is seen in the downward (with respect to gravity) migration of the nucleus along the proximal face of the spore and the subsequent downward growth of the primary rhizoid. When spores are germinated on a clinostat the direction of nuclear migration and subsequent primary rhizoid growth is random. However, in each case the direction of nuclear migration predicts the direction of rhizoid elongation. Although it is the most obvious movement, the downward migration is not the first movement of the nucleus. During the polarity-determination window, the nucleus moves randomly within a region centered behind the trilete marking. While the polarity of many fern spores has been reported to be controlled by light, spores of C. richardii are the first documented to have their polarity influenced by gravity. Directional white light also affects the polarity of these spores, but this influence is slight and is secondary to that of gravity.
Cornopteris christenseniana is a "sterile" interspecific triploid hybrid of diploid C. crenulatoserrulata and tetraploid C. decurrenti-alata. Morphological and cytological studies show that, of 41 young plants of Cornopteris that have been propagated naturally in the Fern Garden of the Botanical Gardens, University of Tokyo, 30 plants are the sterile C. christenseniana, 10 are fertile C. decurrenti-alata and 1, fertile C. crenulatoserrulata. This proportion supports the view that the young plants of C. christenseniana are derived from spores of reproductively mature plants of the species cultivated. Cytogenetic observations and culture experiments show that C. christenseniana produces normal spores in various proportions in some sporogenetic pathways that are aberrant from the ordinary process in sexual and apomictic ferns. Under culture conditions, normal spores germinate in rough proportion to the frequency of normal spores, and sporophytes are apogamously produced in rough proportion to the frequency of spore germination. As a whole, the rates of spore germination and apogamous sporophyte development vary according to the specific plant. Taken together, these observations suggest that C. christenseniana is an incipient apomict.
Polymerase chain reaction (PCR)-based nuclear DNA markers were developed for fern species. We first determined the partial nucleotide sequence of cDNA of the pgiC gene encoding cytosolic phosphoglucose isomerase from Dryopteris caudipinna, and then PCR primers for exon-primed, intron-crossing (EPIC) amplifications were designed. The EPIC primers are universally applicable to the most derived indusiate fern families such as Dryopteridaceae, Thelypteridaceae, and Woodsiaceae. The PCR products of primers 14F/16R containing two introns are moderate in size (534 bp-ca.1000 bp) and are possibly of value in phylogenetic reconstruction at specific and generic levels. Codominant nuclear DNA markers applicable to the estimation of mating systems and other population genetic studies were also developed by a combination of single-strand conformation polymorphism (SSCP) and EPIC amplification using primers 14F/15R and 15F/16R. In order to provide a case study using these markers, allelic variation of PCR products using 15F/16R was examined in populations of Arachniodes standishii (Dryopteridaceae).
The level and pattern of genetic variation was analyzed in four species of the fern genus Adiantum L., A. hispidulum Sw., A. incisum Forrsk., A. raddianum C.Presl, and A. zollingeri Mett. ex Kuhn, originating from South India, using the ISSR fingerprinting method. The populations of Adiantum possessed a considerable level of genetic variation, the diversity indices ranging from 0.284 to 0.464. Only 12% of the ISSR markers found were restricted to one species only, and 54% were detected in all four species. The analysis of molecular variance revealed that 71.1% of variation was present within populations. The proportion of variation detected among species was only 18.5% while the proportion of variation among populations within species equalled 10.4%. Despite the low level of intrageneric differentiation, the discriminant analysis and clustering of genetic distances indicated that the four Adiantum species are genetically distinct. The F(ST) values calculated for the species were low, varying from 0.089 to 0.179. No linkage disequilibrium was detected between the loci. Such low level of differentiation among populations and the presence of linkage equilibrium reflect that the life history of Adiantum ferns apparently involves common or relatively common sexuality, effective wind-dispersal of spores and outcrossing.
Ferning of amniotic fluid was studied in early pregnancy. Arborization was demonstrated during the interval of 6 1/2 to 16 weeks by flame-drying. Air-drying yielded a spectrum of crystallization from none prior to 8 weeks to full ferning by 16 weeks. Technical differences are stressed.
The spontaneous photon emission (chemiluminescence) from Drosophila melanogaster fed chemical mutagens, polycyclic aromatic hydrocarbon quinones, and a carcinogenic bracken fern was studied. The fly chemiluminescence was evidently enhanced by mutagen or carcinogen administration and was increased proportionally to the administered amount of tested compound. Strong chemiluminescence was observed especially at the larval stage. Living larvae emitted stronger chemiluminescence than their homogenate. The chemiluminescence from Drosophila melanogaster fed polycyclic aromatic hydrocarbon quinones showed a linear relation with the mutation frequency in the Drosophila wing spot test. The chemiluminescence from flies fed a bracken fern decreased by the addition of free radical scavengers and active oxygen quenchers. The phosphatidylcholine hydroperoxide concentration in the flies was increased proportionally with the chemiluminescence intensity. It seems that the free radical formation is stimulated as shown by the enhanced chemiluminescence in mutagen- or carcinogen-dosed flies, and as a result, lipid peroxide accumulation accompanies mutation in Drosophila melanogaster.
Effect of storage on carcinogenic activity of bracken fern was examined with inbred strain ACI rats of both sexes. The experiment was broken down into 3 groupings: Group I received a diet containing fresh dry bracken powder: Group II received a diet which contained the same dry bracken powder used in Group I but preserved for 1 year at 4 degrees C (Group II-C) or room temperature (Group II-R); Group III received the diet containing bracken powder preserved for 2 years at 4 degrees C (Group III-C) or room temperature (Group III-R). Three control groups corresponding to Groups I, II and III were fed a normal basal diet. Significant differences in incidence of ileal tumors were observed between Group I and both groups of Group III and latent period of intestinal tumors in Group II or III was longer than that of Group I. The results indicate a decreased carcinogenic activity of bracken fern by preservation.
Phytoremediation techniques are receiving more attention as decontaminating strategies. Phytoextraction makes use of plants to transfer contaminants from soil to the aboveground biomass. This research is devoted to study the effects of arbuscular mycorrhizae (AM) on growth and As hyperaccumulation in the Chinese brake fern Pteris vittata. We grew for 45 days P. vittata sporophytes, infected or not infected with the AM fungi Glomus mosseae or Gigaspora margarita, in a hydroponic system on quartz sand. As-treated plants were weekly fed with 25 ppm As. The As treatment produced a dramatic increase of As concentration in pinnae and a much lower increase in roots of both mycorrhizal and control plants. Mycorrhization increased pinnae dry weight (DW) (G. margarita = G. mosseae) and leaf area (G. margarita > G. mosseae), strongly reduced root As concentration (G. mosseae > G. margarita), and increased the As translocation factor (G. mosseae > G. margarita). The concentration of phosphorus in pinnae and roots was enhanced by both fungi (G. margarita > G. mosseae). The quantitatively different effects of the two AM fungi on plant growth as well as on As and P distribution in the fern suggest that the As hyperaccumulation in P. vittata can be optimized by a careful choice of the symbiont.
This study measured antioxidative responses of Chinese brake fern (Pteris vittata L.) upon exposure to arsenic (As) of different concentrations. Chinese brake fern was grown in an artificially-contaminated soil containing 0 to 200 mg As kg(-1) (Na2HAsO4) for 12 weeks in a greenhouse. Soil As concentrations at < or =20 mg kg(-1) enhanced plant growth, with 12-71% biomass increase compared to the control. Such beneficial effects were not observed at >20 mg As kg(-1). Plant As concentrations increased with soil As concentrations, with more As being accumulated in the fronds (aboveground biomass) than in the roots and with maximum frond As concentration being 4675 mg kg(-1). Arsenic uptake by Chinese brake enhanced uptake of nutrient elements K, P, Fe, Mn, and Zn except Ca and Mg, whose concentrations mostly decreased. The contents of non-enzymatic antioxidants (glutathione, acid-soluble thiol) followed similar trends as plant As concentrations, increasing with soil As concentrations, with greater contents in the fronds than in the roots especially when exposed to high As concentrations (>50 mg kg(-1)). The activities of enzymatic antioxidants (superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase) in Chinese brake followed the same trends as plant biomass, increasing with soil As up to 20 mg kg(-1) and then decreased. The results indicated though both enzymatic and non-enzymatic antioxidants played significant roles in As detoxification and hyperaccumulation in Chinese brake, the former is more important at low As exposure (< or =20 mg kg(-1)), whereas the latter is more critical at high As exposure (50-200 mg kg(-1)).
We sequenced transcripts from all putative genes for proteins, rRNAs, and a selection of gene-encoding tRNAs in the chloroplast genome of the fern Adiantum capillus-veneris. We detected 350 RNA editing sites when the cDNA sequence was compared to that of the genomic DNA. Of these sites, 10% were U-to-C edits and 90% were C-to-U edits. RNA editing created 19 new start codons, three new stop codons, and "repaired" 26 internal stop codons. Of the 332 editing sites that altered a codon, 26% were in the first codon position, 68% in the second, and 6% in the third. We also detected 21 silent edits, as well as 19 edits that were in untranslated regions, including introns and the anticodon of tRNA(Leu). The latter edit provided a tRNA that is not otherwise encoded in this genome and accounts for a heavily used leucine codon. The level of RNA editing in this fern is more than ten times that of any other vascular plant examined across an entire chloroplast genome. A previous study found even higher levels of editing in a hornwort (942 sites). This suggests that the relatively low levels of editing in seed plants (less than 0.05%) may not be typical for land plants, and that RNA editing may play a major role in chloroplast genome processing. Additionally, we found that 53 editing sites in A. capillus-veneris are homologous to editing sites in the hornwort, and some other land plants. This implies that a major component of RNA editing sites have been conserved for hundreds of millions of years.
Sword brake fern (Pteris ensiformis Burm.) is an ingredient in most of the traditional herbal beverage formulas in Taiwan; however, no information is available to explain its bioactivity. The aim of this study is to elucidate the molecular pharmacological activity in the aqueous extract of sword brake fern (SBF). We found that SBF (0.05-0.25 mg/ml) slightly induced TNF-alpha, IL-6, NO (nitric oxide) and PGE2 (prostaglandin E2) production in unstimualted murine macrophages, RAW264.7 cells. Furthermore, SBF (0.05-0.25 mg/ml) dose-dependently suppressed LPS-induced TNF-alpha, IL-1beta, IL-6, NO and PGE2 in activated RAW264.7 cells without exerting cytotoxicity. Further analysis of molecular mechanisms revealed that SBF prominently repressed LPS-induced iNOS (inducible nitric oxide synthase) and COX-2 (cyclooxygenase-2) promoter activities. Activation of the transcription factor NF-kappaB, which is one of the important pathways for transduction of LPS-stimulated inflammatory mediator producing signals, was suppressed by SBF in a dose-dependent manner, as demonstrated by both electrophoretic mobility shift assay (EMSA) and transfection with pNF-kappaB-Luc plasmid. These results suggest that SBF attenuates inflammatory mediator synthesis of activated macrophages partially through a NF-kappaB-dependent pathway. The immunomodulatory activity of SBF supports its traditional health promotion effect.
Northern analyses of U14snoRNAs in different plant species showed the expected hybridising band of approximately 120 nt in monocotyledonous and dicotyledonous angiosperms. In the lower plant, Bird's nest fern (Asplenium nidus), U14s were larger and three hybridising RNAs of approximately 190, 210 and 250 nt were observed. RT-PCR cloning of all three size variants using primers to the conserved 5' and 3' ends of higher plant U14snoRNAs showed large insertions in one of the plant-specific regions corresponding in position to the yeast U14-specific Y-domain. The insertions are pyrimidine-rich in their 5' halves and purine-rich in their 3' halves and are likely to be sequestered in stem structures consistent with the proposed model of U14snoRNA secondary structure. The 5' flanking regions of one of the fern U14 variants was generated by PCR and lacked classical plant snRNA promoter elements.
Schizaea pusilla is a pteridophyte with several unique developmental characteristics. In contrast to most other fern species, S. pusilla gametophytes remain filamentous throughout their development, and the gametophytes are associated with an endophytic fungus which appears to be mycorrhizal. In terms of tropistic responses, apical filament cells of young gametophytes are negatively phototropic compared with germ filaments of other ferns which exhibit positive phototropism. Cryofixation (propane jet freezing and high-pressure freezing) in conjunction with freeze substitution electron microscopy was used to study young gametophytes. The results demonstrate that apical filament cells have a distinctive structural polarity and that rhizoids also can be successfully frozen by these methods. The cytoskeleton and endomembrane system were particularly well preserved in cryofixed cells. In addition, Schizaea gametophytes were used as a test system to evaluate potential artifacts of propane jet freezing and high pressure freezing. There was little apparent difference in ultrastructure between cells cryofixed by either freezing method. These gametophytes will be useful in determining the effectiveness of cryofixation techniques and as a model system in tip growth studies.
Because of their high chromosome numbers, homosporous vascular plants were considered paleopolyploids until recent enzyme electrophoretic studies rejected this hypothesis by showing that they express only diploid numbers of isozymes. In polyploid sporophytes of the homosporous fern pelleae rufa, however, progressive diminution of phosphoglucoisomerase activities encoded by one ancestral genome culminates in tetraploid plants exhibiting a completely diploidized electrophoretic phenotype for this enzyme. The demonstration that such gene silencing can make a polyploid fern look isozymically like a diploid questions the validity of isozyme evidence for testing the paleopolyploid hypothesis and supports the proposed role of polyploidization followed by genetic diploidizaton in the evolutionary history of homosporous pteridohytes.
The chloroplast genome of most land plants is highly conserved. In contrast, physical and gene mapping studies have revealed a highly rearranged chloroplast genome in species representing four families of ferns. In all four, there has been a rare duplication of the psbA gene and the order of the psbA, 16S, and 23S rRNA genes has been inverted. Our analysis shows that the described rearrangement results from a minimum of two inversions within the inverted repeat. This chloroplast DNA structure provides unambiguous evidence that phylogenetically links families of ferns once thought to belong to different major evolutionary lineages.
A lectin was purified from rhizomes of the fern Phlebodium aureum by affinity chromatography on mannose-Sepharose. The lectin, designated P. aureum lectin (PAL), is composed of two identical subunits of approximately 15 kDa associated by noncovalent bonds. From a cDNA library and synthetic oligonucleotide probes based on a partial amino acid sequence, 5'- and 3'-rapid amplification of cDNA ends allowed the generation of two similar full-length cDNAs, termed PALa and PALb, each of which had an open reading frame of 438 bp encoding 146 amino acid residues. The two proteins share 88% sequence identity and showed structural similarity to jacalin-related lectins. PALa contained peptide sequences exactly matching those found in the isolated lectin. PALa and PALb were expressed in Escherichia coli using pET-22b(+) vector and purified by one-step affinity chromatography. Native and recombinant forms of PAL agglutinated rabbit erythrocytes and precipitated with yeast mannan, dextran, and the high mannose-containing glycoprotein invertase. The detailed carbohydrate-binding properties of the native and recombinant lectins were elucidated by agglutination inhibition assay, and native lectin was also studied by isothermal titration calorimetry. Based on the results of these assays, we conclude that this primitive vascular plant, like many higher plants, contains significant quantities of a mannose/glucose-binding protein in its storage tissue, whose binding specificity differs in detail from either legume mannose/glucose-binding lectins or monocot mannose-specific lectins. The identification of a jacalin-related lectin in a true fern reveals for the first time the widespread distribution and molecular evolution of this lectin family in the plant kingdom.
AIM: To describe changes in blood and urine analytes in a large group of cattle exposed to chronic bracken fern toxicity, in order to identify parameters of potential diagnostic value. METHODS: The study was conducted on two livestock farms on which bovine enzootic haematuria (BEH) was known to occur; Farm A grazed a local breed of cows and Farm B grazed Friesians. Group A1 comprised 66 cows from Farm A, Group B 54 cows from Farm B, and Group A2 13 heifers from Farm A. Ten healthy cows were used as controls. A complete physical examination was performed (Group A1), and blood (all groups) and urine (Groups A1 and B) samples were collected. Necropsies and histopathology were undertaken on four cows. RESULTS: Anaemia, leucopenia, monocytosis, thrombocytopenia, hypergammaglobulinaemia, microhaematuria and proteinuria were detected. Multivariate statistical analyses established three phases of the disease of increasing severity; an initial phase, characterised by an extremely high monocytosis and otherwise normal parameters; an intermediate phase, characterised by monocytosis and moderate changes to other analytes; and a final phase, characterised by normal levels of monocytes and many changes to other analytes. CONCLUSIONS AND CLINICAL RELEVANCE: Monocytosis, detected in 31% of the younger animals, could represent an initial response to consumption of bracken fern and might be useful as an early haematological marker of BEH.