Search for evolutionary roots of land plant arabinogalactan-proteins in charophytes: presence of a rhamnogalactan-protein in Spirogyra pratensis (Zygnematophyceae).

Charophyte green algae (CGA) are assigned to be the closest relatives of land plants and therefore enlighten processes in the colonization of terrestrial habitats. For the transition from water to land, plants needed significant physiological and structural changes, as well as with regard to cell wall composition. Sequential extraction of cell walls of Nitellopsis obtusa (Charophyceae) and Spirogyra pratensis (Zygnematophyceae) offered a comparative overview on cell wall composition of late branching CGA. Because arabinogalactan-proteins (AGPs) are considered common for all land plant cell walls, we were interested in whether these special glycoproteins are present in CGA. Therefore, we investigated both species with regard to characteristic features of AGPs. In the cell wall of Nitellopsis, no hydroxyproline was present and no AGP was precipitable with the ß-glucosyl Yariv's reagent (ßGlcY). By contrast, ßGlcY precipitation of the water-soluble cell wall fraction of Spirogyra yielded a glycoprotein fraction rich in hydroxyproline, indicating the presence of AGPs. Putative AGPs in the cell walls of non-conjugating Spirogyra filaments, especially in the area of transverse walls, were detected by staining with ßGlcY. Labelling increased strongly in generative growth stages, especially during zygospore development. Investigations of the fine structure of the glycan part of ßGlcY-precipitated molecules revealed that the galactan backbone resembled that of AGPs with 1,3- 1,6- and 1,3,6-linked Galp moieties. Araf was present only in small amounts and the terminating sugars consisted predominantly of pyranosidic terminal and 1,3-linked rhamnose residues. We introduce the term 'rhamnogalactan-protein' for this special AGP-modification present in S. pratensis.

Pyrogallol from Spirogyra neglecta Inhibits Proliferation and Promotes Apoptosis in Castration-Resistant Prostate Cancer Cells via Modulating Akt/GSK-3ß/ß-catenin Signaling Pathway.

Castration-resistant prostate cancer (CRPC) is an advanced form of prostate cancer associated with poor survival rates. The high proliferation and metastasis rates have made CRPC one of the most challenging types of cancer for medical practitioners and researchers. In this study, the anti-cancer properties and inhibition of CRPC progression by S. neglecta extract and its active constituents were determined using two CRPC cell lines, DU145 and PC3. The ethyl acetate fraction of S. neglecta (SnEA) was obtained using a solvent-partitioned extraction technique. The active constituents of SnEA were then determined using the HPLC technique, which showed that SnEA mainly contained syringic acid, pyrogallol, and p-coumaric acid phenolic compounds. After the determination of cytotoxic properties using the SRB assay, it was found that pyrogallol, but not the other two major compounds of SnEA, displayed promising anti-cancer properties in both CRPC cell lines. SnEA and pyrogallol were then further investigated for their anti-proliferation and apoptotic induction properties using propidium iodide and Annexin V staining. The results showed that SnEA and pyrogallol inhibited both DU145 and PC3 cell proliferation by inducing cell cycle arrest in the G0/G1 phase and significantly decreased the expression of cell cycle regulator proteins (cyclin D1, cyclin E1, CDK-2, and CDK-4, p < 0.001). SnEA and pyrogallol treatments also promoted apoptosis in both types of CRPC cells through significantly downregulating anti-apoptotic proteins (survivin, Bcl-2, and Bcl-xl, p < 0.001) and upregulating apoptotic proteins (cleaved-caspase-9, cleaved-caspase-3 and cleaved-PARP-1, p < 0.001). Mechanistic study demonstrated that SnEA and pyrogallol inactivated the Akt signaling pathway leading to enhancement of the active form of GSK-3ß in CRPC cell lines. Therefore, the phosphorylation of ß-catenin was increased, which caused degradation of the protein, resulting in a downregulation of ß-catenin (unphosphorylated form) transcriptional factor activity. The current results reflect the potential impact of S. neglecta extract and pyrogallol on the management of castration-resistant prostate cancer.

Multifunctional Spirogyra-hyalina-Mediated Barium Oxide Nanoparticles (BaONPs): Synthesis and Applications.

This research aims to biosynthesize Barium oxide nanoparticles (BaONPs) for biomedical applications, using Spirogyra hyalina as a stabilizing and reducing agent. UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray, X-ray diffraction (XRD), and scanning electron microscopy (SEM) were used to physiochemically characterize the barium oxide nanoparticles, while antibacterial, minimum inhibitory concentration, antifungal, free radicle scavenging, and anti-inflammatory assay were performed to assess the therapeutic potential of the synthesized BaONPs. Fourier transform infrared spectroscopy revealed bands at 615 and 692 cm-1 that corresponded to the formation of BaONPs. Scanning electron microscopy revealed the spherical and flower-shaped morphology of BaONPs having an average diameter of 64.01 ± 2.0 nm. Both Gram-positive and Gram-negative bacterial growth was halted by the barium nanoparticles, demonstrating their efficacy up to 19.12 ± 0.31 mm against E. coli, 18.83 ± 0.44 mm against Klebsiella pneumoniae, 17.31 ± 0.59 mm against P. aeruginosa, 16.56 ± 0.37 mm against S. aureus, and 15.75 ± 0.38 mm against S. epidermidis, respectively. The minimum inhibitory concentration was 9.0, 6.3, 5.5, 4.5, and 2.0 µg/mL for S. aureus, Klebsiella pneumoniae, S. epidermidis, P. aeruginosa, and E. coli, respectively. BaONPs were not that effective against fungal strains such as Rhizoctonia solani, Fusarium solani, and Fusarium proliferatum. The BaONPs exhibited potent anti-inflammatory and antioxidant activity through inhibiting cyclooxygenases type 1 (43.12 ± 1.21%) and 2 (41.23 ± 1.56%), and DPPH free radicles up to 43.52 ± 0.29% at 400 µg/mL. In conclusion, the biomolecules derived from Spirogyra hyalina have demonstrated remarkable ability to generate stable nanoparticles, offering promising prospects for their utilization as therapeutic agents and coating materials in various biomedical applications.

Biofabrication of Fe3O4 Nanoparticles from Spirogyra hyalina and Ajuga bracteosa and Their Antibacterial Applications.

Iron oxide nanoparticles (NPs) have attracted substantial interest due to their superparamagnetic features, biocompatibility, and nontoxicity. The latest progress in the biological production of Fe3O4 NPs by green methods has improved their quality and biological applications significantly. In this study, the fabrication of iron oxide NPs from Spirogyra hyalina and Ajuga bracteosa was conducted via an easy, environmentally friendly, and cost-effective process. The fabricated Fe3O4 NPs were characterized using various analytical methods to study their unique properties. UV-Vis absorption peaks were observed in algal and plant-based Fe3O4 NPs at 289 nm and 306 nm, respectively. Fourier transform infrared (FTIR) spectroscopy analyzed diverse bioactive phytochemicals present in algal and plant extracts that functioned as stabilizing and capping agents in the fabrication of algal and plant-based Fe3O4 NPs. X-ray diffraction of NPs revealed the crystalline nature of both biofabricated Fe3O4 NPs and their small size. Scanning electron microscopy (SEM) revealed that algae and plant-based Fe3O4 NPs are spherical and rod-shaped, averaging 52 nm and 75 nm in size. Energy dispersive X-ray spectroscopy showed that the green-synthesized Fe3O4 NPs require a high mass percentage of iron and oxygen to ensure their synthesis. The fabricated plant-based Fe3O4 NPs exhibited stronger antioxidant properties than algal-based Fe3O4 NPs. The algal-based NPs showed efficient antibacterial potential against E. coli, while the plant-based Fe3O4 NPs displayed a higher zone of inhibition against S. aureus. Moreover, plant-based Fe3O4 NPs exhibited superior scavenging and antibacterial potential compared to the algal-based Fe3O4 NPs. This might be due to the greater number of phytochemicals in plants that surround the NPs during their green fabrication. Hence, the capping of bioactive agents over iron oxide NPs improves antibacterial applications.

Anti-diabetic, anti-inflammatory and muscle relaxant activities of extracts from Spirogyra varians (Hassall) Kuetzing.

Spirogyra varians (Hassall) Kuetzing is one of the edible freshwater filamentous green algae. This alga is commonly used as local food in northern and northeastern Thailand. A study on pharmacological activities of S. varians has not yet been extensively performed. Therefore, this study was established to investigate the anti-diabetic, anti-inflammatory and muscle relaxant activities of the extracts from S. varians. The In vitro α-glucosidase inhibition assay revealed that the propylene glycol extract exhibited the highest α-glucosidase inhibition activity compared to the methanol and ethanol extracts. However, all the extracts possess α-glucosidase inhibition activity less potent than Acarbose, an α-glucosidase inhibitor. The propylene glycol extract showed the highest inhibition of nitric oxide production in LPS-stimulated RAW 264.7 macrophage cells compared to the methanol and ethanol extracts. Nevertheless, the inhibition activity of the extracts was less potent than diclofenac, an anti-inflammatory drug. Whereas, the methanol extract exhibited the highest muscle relaxant activity on frog gastrocnemius compared to the ethanol and propylene glycol extracts. The methanol extract displayed muscle relaxant activity with a similar potent to Indomethacin, a pain relief drug. This study indicates that S. varians can be used as an effective novel natural resource for developing anti-diabetic, anti-inflammatory and muscle relief agents.

Potential of live Spirogyra sp. in the bioaccumulation of copper and nickel ions: A study on suitability and sustainability.

AIM: Various industrial and municipal wastes are the major sources of heavy metal contamination in water causing significant environmental issues. Bioremediation is an effective and affordable solution for the removal of metals and metal pollutants from industrial wastewater. This study aimed to assess the efficacy of live and dead Spirogyra sp. for sorption of metals like of Cu2+ and Ni2+ . METHODS AND RESULTS: The live Spirogyra sp. was used for the uptake of Cu2+ and Ni2+ from their aqueous solutions. The equilibrium data were fitted using a Langmuir and Freundlich isotherm model; the maximum uptakes for Cu2+ and Ni2+ were 29 and 521 mg g-1 , respectively. Scanning electron microscopic (SEM) and infrared (IR) spectroscopic studies of Spirogyra sp. and treated Spirogyra sp. with specific metal ions were used to assess the bonding site and extent of sorption mechanism. CONCLUSION: The initial study showed that this biomass takes up a significant amount of metal ions. Compared to the Langmuir model, the Freundlich model showed better sorption process. The pseudo-second-order rate model represented an enhanced kinetics of metal ion adsorption using live Spirogyra sp. SIGNIFICANCE AND IMPACT OF THE STUDY: As bioaccumulation technology is environmental friendly and potentially cost-effective, live Spirogyra sp. is expected to be a good candidate for managing industrial wastewater.

Bioaccumulation of arsenic(V) from wastewater by live and dead Spirogyra sp.

Contaminated water with arsenic causes a negative impact on socioeconomic status in the concerned area. Existing methods are not much adequate, efficient, and appropriate. Bioremediation of heavy metals with microalgae seems to be a promising and holistic approach to counter the pre-existing associated with heavy metal toxicity. A pure culture of live and dead Spirogyra sp. was tested for its ability to adsorb arsenic(V) and modeling of experimental data was used to interpret the mechanism of bioaccumulation. Langmuir and Freundlich isotherm models were used to explain the sorption of arsenic. The maximum sorption capacity of live Spirogyra sp. was 315 mg/g and dead Spirogyra sp. was 207 mg/g. Mechanism of bioaccumulation for As(V) ions by live and dead Spirogyra sp. were studied using several advanced techniques including Fourier-transform infrared, fluorescence microscopy, and scanning electron microscope. The study summarizes, bioaccumulation of AsO4 -3 by live and dead cells of Spirogyra sp. seems to be promising. The pseudo-second-order rate equation described better the kinetics of As(V) adsorption with good correlation coefficients. The results suggested that live Spirogyra sp. was more suitable to remove As(V) as compared to dead Spirogyra sp.

Heat stress response in the closest algal relatives of land plants reveals conserved stress signaling circuits.

All land plants (embryophytes) share a common ancestor that likely evolved from a filamentous freshwater alga. Elucidating the transition from algae to embryophytes - and the eventual conquering of Earth's surface - is one of the most fundamental questions in plant evolutionary biology. Here, we investigated one of the organismal properties that might have enabled this transition: resistance to drastic temperature shifts. We explored the effect of heat stress in Mougeotia and Spirogyra, two representatives of Zygnematophyceae - the closest known algal sister lineage to land plants. Heat stress induced pronounced phenotypic alterations in their plastids, and high-performance liquid chromatography-tandem mass spectroscopy-based profiling of 565 transitions for the analysis of main central metabolites revealed significant shifts in 43 compounds. We also analyzed the global differential gene expression responses triggered by heat, generating 92.8 Gbp of sequence data and assembling a combined set of 8905 well-expressed genes. Each organism had its own distinct gene expression profile; less than one-half of their shared genes showed concordant gene expression trends. We nevertheless detected common signature responses to heat such as elevated transcript levels for molecular chaperones, thylakoid components, and - corroborating our metabolomic data - amino acid metabolism. We also uncovered the heat-stress responsiveness of genes for phosphorelay-based signal transduction that links environmental cues, calcium signatures and plastid biology. Our data allow us to infer the molecular heat stress response that the earliest land plants might have used when facing the rapidly shifting temperature conditions of the terrestrial habitat.

Chemical Composition, Algicidal, Antimicrobial, and Antioxidant Activities of the Essential Oils of Taiwania flousiana Gaussen.

Taiwania flousiana (T. flousiana) Gaussen is a precious wood in the family Taxodiaceae. This study investigated the chemical components of the essential oil from the stem bark of T. flousiana and its algicidal, antifungal, and antioxidant properties. Sixty-nine compounds representing 89.70% of the stem bark essential oil were identified by GC-MS. The essential oil showed strong anti-algae, anti-bacteria, and anti-fungus activities against the tested species, and antioxidant activities. The IC50 values of the essential oil against chlorophyll a, chlorophyll b, and the total chlorophyll of Spirogyra communis (a species of algae), 24-96 h after the treatment, ranged from 31.77 to 84.92 µg/mL, while the IC50 values of butachlor ranged from 40.24 to 58.09 µg/mL. Ultrastructure changes revealed by the transmission electron microscopy indicated that the main algicidal action sites were the chloroplast and cell wall. The essential oil showed antifungal activities on Rhizoctonia solani (EC50 = 287.94 µg/mL) and Colletotrichum gloeosporioiles (EC50 = 378.90 µg/mL). It also showed bactericidal activities on Ralstonia solanacearum and Staphylococcus aureus, with zones of inhibition (ZOIs) being 18.66 and 16.75 mm, respectively at 40 µg/disk. Additionally, the essential oil possessed antioxidant activity estimated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) method (IC50 = 33.51 µg/mL; IC50 value of the positive control ascorbic acid was 7.98 µg/mL). Thus, the essential oil of this plant might be used as a possible source of natural bioactive molecules in agrochemical industry as well as in food and cosmetic industries.

Heavy Metals Assessment in Water, Sediments, Algae and Two Fish Species from River Swat, Pakistan.

The heavy metals were studied in water, sediments, algae, and various tissues of Glyptosternon reticulatum and Cyprinus carpio from River Swat, Pakistan, using flame atomic absorption spectrophotometer. The Zn, Cu, Pb and Ni were higher in water at sewage site compared to upstream and downstream sites. In sediments, the Ni and Cd were not detected whereas Cu, Pb and Zn were higher at downstream followed by sewage and upstream sites. The Ni and Zn in algae were higher at upstream and sewage sites compared to downstream site whereas Pb and Cd were higher at upstream site compared to sewage and downstream sites and Cu was found same at all the three sites. The heavy metals (Zn > Cu > Pb and Ni) in tissues (liver > gills > skin > muscles) of G. reticulatum was higher than in C. carpio. This study recommends the proper monitoring of River Swat in order to save its water and inhabitant aquatic life.

Isotope Composition of Nitrogen and Stoichiometric Ratios of Elements in Biomass of Spirogyra in Lake Baikal.

Using stable isotope analysis of nitrogen, for the first time the hypothesis on different sources of inorganic nutrients for two groups of littoral algae in Lake Baikal was confirmed. Strongly attached filamentous algae of genus Ulothrix, which developed in the wave-braking zone at depth 0.5 m, and loosely attached filamentous algae of genus Spirogyra, which developed in deeper layers 3.0-5.0 m in a low-turbulence zone, get inorganic nutrients presumably from surface discharge and groundwater inputs, respectively. Besides, stoichiometric ratios C:N and N:P in biomass of the algae indicated that growth of Spirogyra in Lake Baikal was likely limited by nitrogen, while growth of Ulothrix was limited by phosphorus.

Red And far-red regulation of filament movement correlates with the expression of phytochrome and FHY1 genes in Spirogyra varians (Zygnematales, Streptophyta)1.

Spirogyra filaments show unique photomovement that differs in response to blue, red, and far-red light. Phototropins involved in the blue-light movement have been characterized together with downstream signaling components, but the photoreceptors and mechanical effectors of red- and far-red light movement are not yet characterized. The filaments of Spirogyra varians slowly bent and aggregated to form a tangled mass in red light. In far-red light, the filaments unbent, stretched rapidly, and separated from each other. Mannitol and/or sorbitol treatment significantly inhibited this far-red light movement suggesting that turgor pressure is the driving force of this movement. The bending and aggregating movements of filaments in red light were not affected by osmotic change. Three phytochrome homologues isolated from S. varians showed unique phylogenetic characteristics. Two canonical phytochromes, named SvPHY1 and SvPHY2, and a noncanonical phytochrome named SvPHYX2. SvPHY1 is the first PHY1 family phytochrome reported in zygnematalean algae. The gene involved in the transport of phytochromes into the nucleus was characterized, and its expression in response to red and far-red light was measured using quantitative PCR. Our results suggest that the phytochromes and the genes involved in the transport system into the nucleus are well conserved in S. varians.

Spirogyra neglecta Aqueous Extract Attenuates LPS-Induced Renal Inflammation.

Spirogyra neglecta (SN), commonly named "Tao" in Thai, is a genus of filamentous green macroalgae. SN contains polyphenols such as isoquercetin, catechin, hydroquinone and kaempferol. These constituents exhibit beneficial effects including anti-oxidant, anti-gastric ulcer, anti-hyperglycaemia and anti-hyperlipidaemia in both in vitro and in vivo models. Whether SN extract (SNE) has an anti-inflammatory effect in vivo remains unclear. This study examined the effect of SNE on renal function and renal organic transport in lipopolysaccharide (LPS)-induced renal inflammation in rats. Rats were randomised and divided into normal saline (NS), NS supplemented with 1000 mg/kg body weight (BW) of SNE (NS + SNE), intraperitoneally injected with 12 mg/kg BW of LPS and LPS treated with 1000 mg/kg BW of SNE (LPS + SNE). Biochemical parameters in serum and urine, lipid peroxidation concentration, kidney function and renal organic anion and cation transports were determined. LPS-injected rats developed renal injury and inflammation by increasing urine microalbumin, total malondialdehyde (MDA) and inflammatory cytokines, tumor necrosis factor (TNF)-α and interleukin (IL)-1ß protein expression, respectively. In addition, uptake of renal organic anion, [3H]-oestrone sulphate (ES), was reduced in LPS-injected rats together with increased expression of organic anion transporter 3 (Oat3). However, the renal injury and inflammation, as well as impaired Oat3 function and protein expression, were restored in LPS + SNE rats. Accordingly, SNE could be developed as nutraceutical product to prevent inflammation-induced nephrotoxicity.

Inhibitory effect of Spirogyra spp. algal extracts against herpes simplex virus type 1 and 2 infection.

AIMS: To determine the antiviral activities of Spirogyra spp. algal extracts against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2). METHODS AND RESULTS: Spirogyra spp. was extracted using water, ethanol and methanol. Aqueous extract of Spirogyra spp. had the lowest toxicity on Vero cells with the 50% cytotoxicity concentration (CC50 ) of 4363·30 µg ml-1 . As for potent inhibitory effect, the ethanolic extract presented the highest inhibition of viral infection on HSV-1 in the treatment during viral attachment on Vero cells with 50% inhibitory concentration (IC50 ) and selective index (SI) values of 164·20 and 2·17 µg ml-1 . However, the methanolic extract showed the highest inhibition of HSV-2 when treated during viral attachment with IC50 and SI values of 75·03 and 3·34 µg ml-1 . The methanolic extract of Spirogyra spp. also demonstrated significant virucidal effects on viral particles. Therefore, anti-HSV activity at various stages of the viral multiplication cycle was shown. The main active compounds in the active fractions of Spirogyra spp. ethanolic extract against HSV were found to be alkaloids, essential oils and terpenoids. CONCLUSIONS: The highest anti-HSV activity was obtained from the ethanolic extract of Spirogyra spp. The extract inhibited the HSV viral particles and the inhibition was during the viral attachment and the viral multiplication. SIGNIFICANCE AND IMPACT OF THE STUDY: Anti-HSV activity of extract of freshwater green macroalga Spirogyra spp. in Thailand was demonstrated. Therefore, anti-HSV product containing the Spirogyra spp. extract should be developed for treatment of HSV infection.

Algal ancestor of land plants was preadapted for symbiosis.

Colonization of land by plants was a major transition on Earth, but the developmental and genetic innovations required for this transition remain unknown. Physiological studies and the fossil record strongly suggest that the ability of the first land plants to form symbiotic associations with beneficial fungi was one of these critical innovations. In angiosperms, genes required for the perception and transduction of diffusible fungal signals for root colonization and for nutrient exchange have been characterized. However, the origin of these genes and their potential correlation with land colonization remain elusive. A comprehensive phylogenetic analysis of 259 transcriptomes and 10 green algal and basal land plant genomes, coupled with the characterization of the evolutionary path leading to the appearance of a key regulator, a calcium- and calmodulin-dependent protein kinase, showed that the symbiotic signaling pathway predated the first land plants. In contrast, downstream genes required for root colonization and their specific expression pattern probably appeared subsequent to the colonization of land. We conclude that the most recent common ancestor of extant land plants and green algae was preadapted for symbiotic associations. Subsequent improvement of this precursor stage in early land plants through rounds of gene duplication led to the acquisition of additional pathways and the ability to form a fully functional arbuscular mycorrhizal symbiosis.

High-rate algal pond coupled with a matrix of Spirogyra sp. for treatment of rural streams with nutrient pollution.

This study evaluated the unique features of a filamentous algae matrix (FAM) that can be applied to high rate algal ponds (HRAPs) as a promising way to remove nutrient from polluted rural streams. The results show that the HRAPs, coupled with the FAM, effectively removed nitrogen and phosphorus (79.8% and 81.2%, respectively), and achieved high production of DO, with a maximum of 11.0 g O2 g FAM-1 d-1. The FAM functioned wells as a screen to prevent excessive algae loss from the system and obtained relatively high biomass growth rate (0.032 mg L-1 d-1 for nitrogen and 0.344 mg L-1 d-1 for phosphorus). The harvested FAM was a useful fertilizer and the rate of addition of FAM were 1.52 kg d-1 ha-1 of nitrogen and 0.44 kg d-1 ha-1 of phosphorus. Thus, combining the HRAP with the FAM was an effective nutrient removal and resource utilization system for rural streams.

Removal of copper from an electroplating industrial effluent using the native and modified spirogyra.

In the present study, biosorption behavior of a green filamentous alga, spirogyra in its native and modified states was investigated for copper removal from an electroplating industrial effluent. For this, the effluent containing 194 mg·L-1 Cu2+ in sulfate medium was contacted with both forms of spirogyra, under the parametric variations of effluent pH, adsorbent dosage, contact time, and sorption temperature. The study revealed spirogyra as a prominent candidate for removing contaminant metal cation; however, at the same condition, biosorption capacity of modified biomass in gel form was higher than the native spirogyra. At the optimized condition with 6 g sorbent dosage treated to 100 mL effluent for 30 min at pH 6.0 and temperature 20 °C, the maximum 82.8% and 96.4% copper could be adsorbed by the native and modified spirogyra, respectively. The batch sorption data using native biomass followed pseudo-first-order kinetic; exhibiting the multilayer sorption mechanism via surface diffusion could be defined by the Freundlich model. In contrast, the sulfuric acid treated modified spirogyra followed pseudo-second-order kinetics and intra particle diffusion as the rate-limiting step.

Two-Track Control of Cellular Machinery for Photomovement in Spirogyra varians (Streptophyta, Zygnematales).

Plants and freshwater algae devoid of flagella evolved various photomovements to optimize their photosynthetic efficiency. The filaments of Spirogyra varians exhibit complex swaying and undulating movement and form a compact mat which enables them to adjust their light exposure. Photomovement of filament fragments (1-10 cells) was analyzed using various photoreceptor and cytoskeleton inhibitors under monochromatic light. Different patterns of movement were observed under red and blue light. The filaments showed positive phototropism under blue light. Under red light, the filaments bent to undulating shape, but rapidly became unbent by a short exposure to far-red light suggesting the involvement of phytochrome in this movement. The mechanical effector for the red-light response was microtubules; the movement was inhibited effectively by the microtubule inhibitor, oryzalin. The blue-light movement was partially inhibited by the single treatment of either cytochalasin D or oryzalin, but was completely blocked when both chemicals were applied together. Phototropin-signaling inhibitors, wortmannin and LY294002, reversibly inhibited the blue-light movement. Caffeine treatment reversibly stopped the blue-light movement, while the red-light movement was not affected by calcium inhibitors. Our results suggest that the complex photomovement of S. varians is the result of a two-track control of microtubules and microfilaments signaled by the combination of phytochrome and phototropin-like receptors.

Transcriptome Profiling of the Green Alga Spirogyra pratensis (Charophyta) Suggests an Ancestral Role for Ethylene in Cell Wall Metabolism, Photosynthesis, and Abiotic Stress Responses.

It is well known that ethylene regulates a diverse set of developmental and stress-related processes in angiosperms, yet its roles in early-diverging embryophytes and algae are poorly understood. Recently, it was shown that ethylene functions as a hormone in the charophyte green alga Spirogyra pratensis Since land plants evolved from charophytes, this implies conservation of ethylene as a hormone in green plants for at least 450 million years. However, the physiological role of ethylene in charophyte algae has remained unknown. To gain insight into ethylene responses in Spirogyra, we used mRNA sequencing to measure changes in gene expression over time in Spirogyra filaments in response to an ethylene treatment. Our analyses show that at the transcriptional level, ethylene predominantly regulates three processes in Spirogyra: (1) modification of the cell wall matrix by expansins and xyloglucan endotransglucosylases/hydrolases, (2) down-regulation of chlorophyll biosynthesis and photosynthesis, and (3) activation of abiotic stress responses. We confirmed that the photosynthetic capacity and chlorophyll content were reduced by an ethylene treatment and that several abiotic stress conditions could stimulate cell elongation in an ethylene-dependent manner. We also found that the Spirogyra transcriptome harbors only 10 ethylene-responsive transcription factor (ERF) homologs, several of which are regulated by ethylene. These results provide an initial understanding of the hormonal responses induced by ethylene in Spirogyra and help to reconstruct the role of ethylene in ancestral charophytes prior to the origin of land plants.

Evaluating biochemical response of filamentous algae integrated with different water bodies.

The present study prompted the second attempts to evaluate biochemical responses of filamentous algae under different physico-chemical variables in various water bodies in Turkey. These variables were investigated by use of multivariate approach in the years of 2013 (May and November) and 2014 (May and October). Studied ecoregions had the different geographic position, climate, land-use, and anthropogenic activities, could strongly affect physico-chemical variables of water bodies, which caused to change or regulate in algal biomass composition due to the different response of filamentous species. Besides, biochemical responses of species changed at different sampling times and stations. Multivariate analyses indicated that temperature, heavy metals, and nutrient contents of aquatic systems were found to be major variables driving the spatial and temporal occurrence and biochemical contents of filamentous species. Total protein and pigment production by filamentous algae were high in water bodies having high nutrients, whereas they were low in high heavy metal contents. Amount of malondialdehyde (MDA), H2O2, total thiol group, total phenolic compounds, proline, total carbohydrate, and bioaccumulation of metals by filamentous algae were closely related with heavy metal contents of water bodies, indicated by the multivariate approach. Significant increase in aforementioned biochemical compounds with a distinct range of habitats and sensitive-tolerance to environmental conditions could make them highly valuable indicators.