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Mixed-linkage (1[rightward arrow]3,1[rightward arrow]4)-β- d-glucan (MLG) is a hemicellulose reputedly confined to certain Poales. Here, the taxonomic distribution of MLG, and xyloglucan, especially in early-diverging pteridophytes, has been re-investigated. Polysaccharides were digested with lichenase and xyloglucan endoglucanase (XEG), which specifically hydrolyse MLG and xyloglucan, respectively. The oligosaccharides produced were analysed by thin-layer chromatography (TLC), high-pressure liquid chromatography (HPLC) and alkaline peeling. Lichenase yielded oligo-β-glucans from all Equisetum species tested (Equisetum arvense, Equisetum fluviatile, Equisetum scirpoides, Equisetum sylvaticum and Equisetum xtrachyodon). The major product was the tetrasaccharide β-glucosyl-(1[rightward arrow]4)-β-glucosyl-(1[rightward arrow]4)-β-glucosyl-(1[rightward arrow]3)-glucose (G4G4G3G), which was converted to cellotriose by alkali, confirming its structure. Minor products included G3G, G4G3G and a nonasaccharide. By contrast, poalean MLGs yielded G4G3G > G4G4G3G > nonasaccharide > dodecasaccharide. No other pteridophytes tested contained MLG, including Psilotum and eusporangiate ferns. No MLG was found in lycopodiophytes, bryophytes, Chara or Nitella. XEG digestion showed that Equisetum xyloglucan has unusual repeat units. Equisetum, an exceedingly isolated genus whose closest living relatives diverged > 380 million years ago, has evolved MLG independently of the Poales. Equisetum and poalean MLGs share basic structural motifs but also exhibit clear-cut differences. Equisetum MLG is firmly wall-bound, and may tether neighbouring microfibrils. It is also suggested that MLG acts as a template for silica deposition, characteristic of grasses and horsetails.

The ethanolic extracts of three Equisetum species (E. pratense Ehrh., E. sylvaticum L. and E. telmateia Ehrh.) were used to reduce silver ions to silver nanoparticles (AgNPs). The synthesized AgNPs were characterized using UV-Vis spectrophotometry, Fourier Transform Infrared Spectroscopy (FTIR), Energy Dispersive X-ray (EDX), Transmission Electron Microscopy (TEM) and Dynamic Light Scattering (DLS) measurements. FTIR data revealed the functional groups of biomolecules involved in AgNPs synthesis, such as O-H, C-H, C=O, C-O, and C-C. EDX spectroscopy was used to highlight the presence of silver, while DLS spectroscopy provided information on the mean diameter of AgNPs, that ranged from 74.4 to 314 nm. The negative Zeta potential values (−23.76 for Ep–AgNPs, −29.54 for Es–AgNPs and −20.72 for Et–AgNPs) indicate the stability of the obtained colloidal solution. The study also focused on establishing the photocatalytic activity of AgNPs, which is an important aspect in terms of removing organic dyes from the environment. The best photocatalytic activity was observed for AgNPs obtained from E. telmateia, which degraded malachite green in a proportion of 97.9%. The antioxidant action of the three AgNPs samples was highlighted comparatively through four tests, with the best overall antioxidant capacity being observed for AgNPs obtained using E. sylvaticum. Moreover, the biosynthesized AgNPs showed promising cytotoxic efficacy against cancerous cell line MG63, the AgNPs obtained from E. sylvaticum L. providing the best result, with a LD50 value around 1.5 mg/mL.

Background and AimsThroughout the history of fern classification, familial and generic concepts have been highly labile. Many classifications and evolutionary schemes have been proposed during the last two centuries, reflecting different interpretations of the available evidence. Knowledge of fern structure and life histories has increased through time, providing more evidence on which to base ideas of possible relationships, and classification has changed accordingly. This paper reviews previous classifications of ferns and presents ideas on how to achieve a more stable consensus.ScopeAn historical overview is provided from the first to the most recent fern classifications, from which conclusions are drawn on past changes and future trends. The problematic concept of family in ferns is discussed, with a particular focus on how this has changed over time. The history of molecular studies and the most recent findings are also presented.Key ResultsFern classification generally shows a trend from highly artificial, based on an interpretation of a few extrinsic characters, via natural classifications derived from a multitude of intrinsic characters, towards more evolutionary circumscriptions of groups that do not in general align well with the distribution of these previously used characters. It also shows a progression from a few broad family concepts to systems that recognized many more narrowly and highly controversially circumscribed families; currently, the number of families recognized is stabilizing somewhere between these extremes. Placement of many genera was uncertain until the arrival of molecular phylogenetics, which has rapidly been improving our understanding of fern relationships. As a collective category, the so-called ‘fern allies’ (e.g. Lycopodiales, Psilotaceae, Equisetaceae) were unsurprisingly found to be polyphyletic, and the term should be abandoned. Lycopodiaceae, Selaginellaceae and Isoëtaceae form a clade (the lycopods) that is sister to all other vascular plants, whereas the whisk ferns (Psilotaceae), often included in the lycopods or believed to be associated with the first vascular plants, are sister to Ophioglossaceae and thus belong to the fern clade. The horsetails (Equisetaceae) are also members of the fern clade (sometimes inappropriately called ‘monilophytes’), but, within that clade, their placement is still uncertain. Leptosporangiate ferns are better understood, although deep relationships within this group are still unresolved. Earlier, almost all leptosporangiate ferns were placed in a single family (Polypodiaceae or Dennstaedtiaceae), but these families have been redefined to narrower more natural entities.ConclusionsConcluding this paper, a classification is presented based on our current understanding of relationships of fern and lycopod clades. Major changes in our understanding of these families are highlighted, illustrating issues of classification in relation to convergent evolution and false homologies. Problems with the current classification and groups that still need study are pointed out. A summary phylogenetic tree is also presented. A new classification in which Aspleniaceae, Cyatheaceae, Polypodiaceae and Schizaeaceae are expanded in comparison with the most recent classifications is presented, which is a modification of those proposed by Smith et al. (2006, 2008) and Christenhusz et al. (2011). These classifications are now finding a wider acceptance and use, and even though a few amendments are made based on recently published results from molecular analyses, we have aimed for a stable family and generic classification of ferns.

Background The horsetails (Equisetum sp) are known biosilicifiers though the mechanism underlying silica deposition in these plants remains largely unknown. Tissue extracts from horsetails grown hydroponically and also collected from the wild were acid-digested in a microwave oven and their silica 'skeletons' visualised using the fluor, PDMPO, and fluorescence microscopy. Results Silica deposits were observed in all plant regions from the rhizome through to the stem, leaf and spores. Numerous structures were silicified including cell walls, cell plates, plasmodesmata, and guard cells and stomata at varying stages of differentiation. All of the major sites of silica deposition in horsetail mimicked sites and structures where the hemicellulose, callose is known to be found and these serendipitous observations of the coincidence of silica and callose raised the possibility that callose might be templating silica deposition in horsetail. Hydroponic culture of horsetail in the absence of silicic acid resulted in normal healthy plants which, following acid digestion, showed no deposition of silica anywhere in their tissues. To test the hypothesis that callose might be templating silica deposition in horsetail commercially available callose was mixed with undersaturated and saturated solutions of silicic acid and the formation of silica was demonstrated by fluorimetry and fluorescence microscopy. Conclusions The initiation of silica formation by callose is the first example whereby any biomolecule has been shown to induce, as compared to catalyse, the formation of silica in an undersaturated solution of silicic acid. This novel discovery allowed us to speculate that callose and its associated biochemical machinery could be a missing link in our understanding of biosilicification.

Smooth scouringrush is an herbaceous perennial with an extensive underground rhizome system that has invaded no-till dryland production fields in the inland Pacific Northwest. The objective of this field study was to determine whether there were any short- or long-term benefits to tank-mixing chlorsulfuron + metsulfuron with glyphosate for smooth scouringrush control. Field studies were conducted at three sites across eastern Washington from 2020 to 2024. Glyphosate was applied during fallow periods at 0, 1,260, 2,520, and 3,780 g ae ha −1 with and without chlorsulfuron + metsulfuron applied at 21.9 + 4.4 g ai ha −1 . Smooth scouringrush stem density was evaluated 1, 2, and 3 yr after treatment. Chlorsulfuron + metsulfuron provided excellent control of smooth scouringrush (<5 plants m −2 ) for the first 2 yr at all three sites, and there was no observed benefit of tank-mixing with glyphosate. This continued to be the case 3 yr after treatment at two of the sites, but at one site, adding glyphosate at 2,520 or 3,780 g ha −1 to chlorsulfuron + metsulfuron decreased stem density compared to chlorsulfuron + metsulfuron applied alone. For treatments containing glyphosate only, the greatest efficacy 3 yr after treatment was achieved at the highest application rate of 3,780 g ha −1 . Although no short-term benefit was observed in adding glyphosate to chlorsulfuron + metsulfuron for smooth scouringrush control, at one of three sites the duration of control was increased by at least 1 yr with the addition of glyphosate at a rate of 2,520 g ha −1 or more and an organosilicone surfactant as tank-mix partners.

The present study reports, the eco-friendly synthesis of gold nanoparticles (AuNPs) using Equisetum diffusum D. Don. extract, a medicinal plant known for its therapeutic properties. Phytochemicals present in the extract served as reducing and stabilizing agents for synthesizing stable AuNPs with an average size range of 68.8 nm. The biosynthesized AuNPs were characterized using UV–vis spectroscopy, FTIR, XRD, SEM, EDX, and dynamic light scattering (DLS) methods, confirming their stability, morphology, and crystalline nature. The green synthesized ED@AuNPs exhibited promising biological activities, including broad-spectrum antibacterial activity against both Gram-positive and Gram-negative bacteria, with inhibition zones from 24 to 37 mm. The anticancer activity was assessed through an MTT assay against hepatic carcinoma (HePG2) cells, revealing dose-dependent cytotoxicity with maximum inhibition at 200 µg/mL (47.62%). Antidiabetic activity was demonstrated by starch hydrolysis and enzyme kinetics, with significant α-amylase inhibitory activity up to 70.85%, comparable to the standard drug Acarbose. Moreover, antioxidant activity was conformed through FRAP and DPPH assays, indicating strong free radical scavenging activity and reducing ability. The study demonstrates the potential of biosynthesized ED@AuNPs as multifunctional agents with applications in biomedicine, particularly in antibacterial, anticancer, antidiabetic, and antioxidant therapies, offering an eco-friendly and sustainable approach for nanoparticle synthesis.

The anatomical structure of cross-sections of internodes of stems and branches of 9 species and 5 interspecific hybrids of the subgenus Equisetum and Hippochaete (Equisetum, Equisetaceae) was studied: E. arvense L., E. fluviatile L., E. palustre L., E. pratense Ehrh., E. sylvaticum L., E. × mildeanum Rothm. (E. pratense × E. sylvaticum), E. × sergijevskianum CN Page et Gureeva (E. pratense × E. palustre), E. × lofotense Lubienski (E. arvense × E. sylvaticum), E. hyemale L., E. ramosissimum Desf., E. scirpoides Michx, E. variegatum Schleich. ex F. Weber et D. Mohr., E. × moorei Newman (E. hyemale × E. ramosissimum), E. × trachyodon (A. Braun) W. D. J. Koch (E. hyemale × E. variegatum). The species-specific anatomical features of the species of the subgenus Equisetum are as follows: the shape of the ridge on the cross-section (in profile) and the presence of silica spines, the size of the vallecular cavities, the position and size of the mechanical tissue under the ridges. For species from the subgenus Hippochaete, the number of ridges and the shape of the ridge on the cross-section, the outline of the mechanical tissue, the presence of siliceous tubercles are important. For all species, the diagnostic feature is the size and position of the mechanical tissue in the cut, as well as the position and number of layers of the endoderm. The size of the central cavity cannot be used as a diagnostic feature. In this case, it is better to use the relative dimensions of the vallecular cavities to the central cavity. The article gives detailed descriptions of cross-sections.

Background Next-generation sequencing has provided a wealth of plastid genome sequence data from an increasingly diverse set of green plants ( Viridiplantae ). Although these data have helped resolve the phylogeny of numerous clades (e.g., green algae, angiosperms, and gymnosperms), their utility for inferring relationships across all green plants is uncertain. Viridiplantae originated 700-1500 million years ago and may comprise as many as 500,000 species. This clade represents a major source of photosynthetic carbon and contains an immense diversity of life forms, including some of the smallest and largest eukaryotes. Here we explore the limits and challenges of inferring a comprehensive green plant phylogeny from available complete or nearly complete plastid genome sequence data. Results We assembled protein-coding sequence data for 78 genes from 360 diverse green plant taxa with complete or nearly complete plastid genome sequences available from GenBank. Phylogenetic analyses of the plastid data recovered well-supported backbone relationships and strong support for relationships that were not observed in previous analyses of major subclades within Viridiplantae . However, there also is evidence of systematic error in some analyses. In several instances we obtained strongly supported but conflicting topologies from analyses of nucleotides versus amino acid characters, and the considerable variation in GC content among lineages and within single genomes affected the phylogenetic placement of several taxa. Conclusions Analyses of the plastid sequence data recovered a strongly supported framework of relationships for green plants. This framework includes: i) the placement of Zygnematophyceace as sister to land plants ( Embryophyta ), ii) a clade of extant gymnosperms ( Acrogymnospermae ) with cycads +  Ginkgo sister to remaining extant gymnosperms and with gnetophytes ( Gnetophyta ) sister to non- Pinaceae conifers (Gnecup trees), and iii) within the monilophyte clade ( Monilophyta ), Equisetales  +  Psilotales are sister to Marattiales  + leptosporangiate ferns. Our analyses also highlight the challenges of using plastid genome sequences in deep-level phylogenomic analyses, and we provide suggestions for future analyses that will likely incorporate plastid genome sequence data for thousands of species. We particularly emphasize the importance of exploring the effects of different partitioning and character coding strategies.

The sterile stems belonging to the Equisetum species are often used in traditional medicine of various nations, including Romanians. They are highly efficient in treating urinary tract infections, cardiovascular diseases, respiratory tract infections, and medical skin conditions due to their content of polyphenolic derivatives that have been isolated. In this regard, this study aimed to provide the chemical composition of the extracts obtained from the Equisetum species (E. pratense, E. sylvaticum, E. telmateia) and to investigate the biological action in vitro and in vivo. For the chemical characterization of the analyzed Equisetum species extracts, studies were performed by using ultra-high-performance liquid chromatography (UHPLC-DAD). In vitro evaluation of the antioxidant activity of the plant extracts obtained from these species of Equisetum genus was determined. The neuroprotective activity of these three ethanolic extracts from the Equisetum species using zebrafish tests was determined in vivo. All obtained results were statistically significant. The results indicate that E. sylvaticum extract has a significant antioxidant activity; whereas, E. pratense extract had anxiolytic and antidepressant effects significantly higher than the other two extracts used. All these determinations indicate promising results for the antioxidant in vitro tests and neuroprotective activity of in vivo tests, particularly mediated by their active principles.

Rheumatoid arthritis (RA) is a chronic inflammatory disease associated with subsequent damage to the bone joints with a global incidence rate of 0.5–1%. To combat with RA various commercially available anti-inflammatory drugs like non-steroidal anti-inflammatory drugs (NSAIDs) are commonly practiced; however, their long-term exposure often results in eliciting gastrointestinal and renal toxicity. Given this, the scientific communities are searching for an alternative therapeutic option that seems less injurious and equally efficacious. Equisetum diffusum D. Don, from the Equisetaceae family, is a native pteridophyte species of the sub-Himalayan region of India and has been reported to have a diverse array of pharmacological properties. The decoction and macerated whole plant extract has been used by various tribal communities (like Tagin, Galo, Adi, Kukis, Meiteis, Mulam) throughout the tropical and sub-tropical Asian countries for the treatment of arthritis, bone fractures, back pain, and abrasives. The present research is focused on determining the anti-arthritic potential of E. diffusum whole plant methanol extract (EDME) in adjuvant-induced arthritic rats. Oral administration with 250 and 500 mg/kg b.w. doses of EDME significantly restored paw-edema, arthritic scoring, and normal body weight. EDME treatment also normalized the haematological, biochemical, radiological, and histological status when compared to the arthritic control rats. The methanol extract significantly ( p  < 0.05) attenuated arthritis progression by downregulating the gene expression of pro-inflammatory mediators, like COX-2, TNF-α, IL-6, and upregulating the expression of anti-inflammatory mediators PPAR-γ, Iκβ in the blood, in a dose-dependent manner. Significantly, EDME also reduced the serum concentration of COX-2, TNF-α, and IL-6 compared to arthritic control rats ( p  < 0.05). The treatment with EDME also normalized the oxidative stress level in liver by restoring the GSH level, CAT and SOD activities and reducing the elevated MDA level. HPTLC and LC–MS/MS analyses of EDME confirmed the presence of potent polyphenols (chlorogenic acid, 4-hydroxycinnamic acid) and flavonoids (kaempferol), thereby suggesting the anti-arthritic property of the plant. All our findings established the anti-arthritic potential of E. diffusum extract in chronic arthritis model on a strong ground.