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Molecular chaperones are synthesized and accumulated under a variety of unfavorable conditions in all organisms. Heat shock protein 90 (Hsp90) and Hsp60, which are classified into the major classes of molecular chaperones, play important roles in cellular stress responses. In this study, we characterized sterile Ulva pertusa Hsp90 (UpHsp90) and UpHsp60 genes which may be involved in tolerance to thermal and heavy metal stresses in this alga. The UpHsp90 cDNA consisting of 2,118 nucleotides encoded a polypeptide of 705 amino acids (AA). On the other hand, the UpHsp60 cDNA consisting of 1,722 nucleotides encoded a protein whose predicted length was 573 AA. The AA sequence alignment and phylogenetic analyses showed that the UpHsp90 and UpHsp60 proteins were more similar to cytoplasmic Hsp90s and mitochondrial Hsp60s, respectively, than to other types of the respective Hsps. Southern blot analysis indicated that the sterile U. pertusa genome had at least two cytoplasmic Hsp90-encoding genes and two mitochondrial Hsp60-encoding genes. The UpHsp90 and UpHsp60 mRNA levels were significantly affected by diurnal and temperature changes, and slightly affected by exposure to heavy metals. These results suggest that UpHsp90 and UpHsp60 genes play particularly important roles in adaptation to diurnal and temperature changes.

We present the 96 005 bp circular chloroplast genome (cpDNA) of Ulva fasciata. This cpDNA was ∼4000 bp smaller than the cpDNA of Ulva sp. UNA00071828; however, this cpDNA was AT rich (75.1%) similar to Ulva sp. The U. fasciata cpDNA was also similar in gene content (101 identified genes) compared to Ulva sp., which included 71 protein-coding genes, 3 ribosomal RNAs (rRNAs) and 27 transfer RNAs (tRNAs). Only one tRNA, trnN(AUU), that was present in Ulva sp. was absent in U. fasciata. Five introns were present in the following genes of U. fasciata: petB (2), psbD (1), psaB (1) and rrl (1). Ulva sp. lacked introns in psbD and psaB, and introns present in atpA and psbB in Ulva sp. were absent in the homologous genes of U. fasciata. A gene arrangement comparison of both Ulva species showed that a ∼27 000 bp segment of DNA consisting of genes psbB to trnT(UGU) was inverted. Furthermore, a phylogenetic analysis of 1135 bp of the rbcL gene confirmed that this cpDNA and the previously published mitochondrial genome from this sample were indeed from U. fasciata.

The green algal genus Cloniophora has been classified in the Chaetophorales (Chlorophyceae) based on morphological characters. This study uses DNA sequence data from the nucleus (SSU) and the chloroplast (tufA) from collections in the Hawaiian Islands and a culture originating from Portugal to test this classification. Taxonomic identities of contemporary collections were confirmed by sequencing small fragments of DNA (rbcL and SSU) from type specimens, including the generitype, Cloniophora willei L. H. Tiffany. These molecular data show that Cloniophora does not have close affinities to the Chaetophorales and belongs instead to the Ulvales (Ulvophyceae). The morphological features of eight or more reproductive products per cell and a pyrenoid with a traversing thylakoid membrane support the molecular data and confirm the placement of this group in the Ulvales. As this genus does not belong to any recognized family in the Ulvales, the family Cloniophoraceae, containing the single genus Cloniophora, is proposed.

Ulva prolifera (Muller) J. Agardh is the main causative species of the 2008 Yellow Sea green tide incident. We investigated the influences of diluted seawater on the vegetative growth and reproductive cell formation of the alga. The thalli that were cultivated under low salinities (10% and 20%) and low pH values (pH around 7.0) showed obvious and steady biomass gain, while those cultivated under high salinities (40%) and relatively higher pH conditions (pH around 8.0) manifested significant biomass loss. The trend was, however, completely the opposite for reproductive cell formation and there were indications that enrichment, over very wide concentration ranges of both nitrogen and phosphate, could significantly promote vegetative growth. Results also indicated that relatively low salinity and low pH regimes boosted vegetative growth but were unfavorable for reproductive cell formation and vice versa. Based on these results, the possible origin and development mechanisms of the green tide event are discussed. Eutrophication in the Changjiang River estuary and adjacent sea areas, as well as extremely high freshwater inflows before, and during, the flood of 2007 - due to the full operation of large- scale water facilities in the area - may have both played an important role in the formation and development of the green tide event.

The macroalga Ulva limnetica K. Ichihara et S. Shimada is the only known Ulva species to be distributed exclusively in freshwater and is restricted to freshwater bodies in the Ryuku archipelago. Molecular phylogenetic analysis suggests that U. limnetica originally evolved from marine forms of Ulva. The mechanisms of adaptation to freshwater in Ulva spp. are poorly understood. In this study, we isolated genes potentially involved in adaptation or tolerance to freshwater conditions in U. limnetica, using suppression subtractive hybridization between mRNAs of samples cultured in freshwater and seawater conditions. A total of 219 genes, up-regulated by the exposure of the macroalga to freshwater, were isolated. Reverse transcription–PCR (RT–PCR) revealed 39 clones, including malate dehydrogenase, soluble starch synthase, triosephosphate isomerase, plastid ribosomal protein, DnaJ-like protein, and chloroplast ascorbate peroxidase (APX), which were specifically or preferentially expressed in freshwater conditions. These 39 clones were also analyzed for their temporal transcriptional response to freshwater conditions. A large majority of these up-regulated genes showed a transient peak of expression after 1–4 h, followed in the next 24 h by a decrease to a stable level (over the 7 d of the experiment). After the initial response peak, the level of expression either remained higher than in the control (long-term response) or returned to a level similar to pretreatment level. A few genes showed a more delayed response (i.e., after several days) to freshwater exposure. Finally, we discussed the possible contributions of the freshwater-induced genes in the acquisition of freshwater adaptation or tolerance of U. limnetica.

Four different seaweed extracts were employed as the dyes of dye sensitized solar cells (DSSCs) to investigate the light-electron efficiency. The sensitizers, extracted from Nannochloropsis spp., Tetraselmis spp., Gracilaria spp., and Ulvales spp., showed their light-electronic transfer ability in different light intensities. Among them, Ulvales output a higher light-voltage, about 0.4 V. The output voltage increased when light intensity increased. Gracilaria extract produced a higher output voltage at 35 Lux, but its output voltage decreased over 500 Lux. The sensitizers extracted from these seaweeds had monochromatic incident photon-to-electron conversion efficiencies (IPCE) between 23-61% in 220-260 nm wavelengths. Among them, Ulvales output higher IPCE than Tetraselmis and Nannochloropsis. SEM analysis of DSSC surfaces revealed that the efficiency of seaweed DSSCs was governed by chlorophyll size. The chlorophyll particle size of Ulvales spp. was the largest. The chlorophyll particle size of Gracilaria spp. was the smallest and yielded the lowest IPCE.

The influence of temperature on the duration of infradian (over 28 h) rhythms of reproduction in the green alga Ulva fenestrata was studied in the laboratory under controlled conditions combining four temperatures (5, 10, 15, and 20°C), two irradiance levels (40 and 60 μE/(m2 s)) and neutral daylengths (12: 12 h light: dark). The rise in water temperature explained 78.4% of the reduction in the reproduction cycles (from 30 to 5 days). It is suggested that U. fenestrata has an endogenous reproductive rhythm with a period of 5 days. In unfavorable conditions, one or more reproduction cycles are omitted, and formation of gametes or spores attains a periodicity of 10, 15, or more days.

Ulva (Enteromorpha) prolifera, widely distributed from the intertidal to the upper subtidal zones around the world, was the dominant species of the massive green tides in the Yellow Sea in the summers of 2007, 2008, and 2009. However, little is known about its intra-species genetic diversity. In this study, six attached and seven floating U. prolifera samples collected from different sites distributed from the north of the Yellow Sea to the south of the East China Sea were taken in inter-simple sequence repeat (ISSR) analysis. Based on the results of the 90 polymorphic bands from four ISSR primers, the genetic diversity level of the floating samples (H = 0.1663, I = 0.2608) was found to be lower than that of the attached samples (H = 0.2105, I = 0.3346). Unweighted pair-group mean analysis (UPGMA) and principal coordinate analysis (PCoA) suggested that floating U. prolifera samples in the Yellow Sea from 2007 to 2009 had a close genetic relationship, and the floating samples were separated from the attached samples. Genetic differentiation and limited gene flow among attached U. prolifera populations were indicated by analysis of molecular variance.

Distromatic foliose blades of the algal genus Ulva are notoriously difficult to identify due to their simple morphologies and few diagnostic characteristics that often exhibit intraspecific variation and interspecific overlap. Hence, species differentiation is difficult and diversity estimates are often inaccurate. Two major goals of this study were to assess the diversity of distromatic Ulva spp. in the Great Bay Estuarine System (GBES) of New Hampshire and Maine, USA, and to compare historical and present day records of these species. Molecular analysis (using ITS sequences) of field-collected specimens revealed four distinct taxa: Ulva lactuca, U. rigida, U. compressa, and U. pertusa. Prior to molecular screening, Ulva lactuca was the only distromatic Ulva species reported for the GBES. Ulva pertusa and the foliose form of U. compressa are newly recorded for the Northwest Atlantic, and the range of U. rigida has been extended. Molecular analysis of historical herbarium voucher specimens indicates that ...

Seaweed cultivation is imperative to augment increasing industrial demand. Ulva fasciata Delile is a potential seaweed for cultivation with applications in food industries. There is a renewed interest in large-scale aquaculture of this species in India due to its envisaged demand in snack food products. In the present study, we have successfully demonstrated the possibility of inducing zoospores in vegetative tissue, effective regeneration and improved growth in this seaweed by manipulating salinity (from 15 to 30 psu) and temperature (from 15 to 35°C). The optimum salinity and temperature requirement for zoospores induction were found to be 15 psu and 25°C, respectively. The quadriflagellate zoospores showed negative phototaxis and the settlement and germination pattern similar to several other green seaweeds. The optimum regeneration (78.53 ± 10.05%) was recorded at 25°C and 30 psu salinity. The maximum daily growth rate (16.1 ± 0.28%) was at 25°C and 30 psu salinity which corresponded to the field conditions. This method could be further refined at nursery culture to achieve artificial seeding essential for the success of commercial cultivation of this seaweed.

The lipid and fatty acid compositions of 27 tropical macroalgae belonging to the three phyla, Chlorophyta, Phaeophyta and Rhodophyta, were studied from a nutritional and chemotaxonomic perspective. The lipid content varied widely among the species and ranged from 0.57% to 3.5% on a dry weight basis (p ⩽ 0.01). Chlorophyta members showed higher C18PUFAs contents than did C20 PUFAs while for Rhodophyta the trend was opposite. The Phaeophyta members displayed a profile of C18PUFAs similar to that of Chlorophyta and of C20PUFAs to that of Rhodophyta. Both Phaeophyta and Rhodophyta species were rich in arachadonic acid (AA) and eicosopentaenoic acid (EPA) and Ulvales in docosahexaenoic acid (DHA) content. Most of the species studied had a nutritionally beneficial n6/n3 ratio (0.61–5.15:1). Further, the principal component analysis clearly segregated the three phyla by their FA composition and hierarchical cluster analysis altogether classified them into six distinct groups, suggesting that FAs can be used as a tool for chemotaxonomic studies.

The rbcL gene of Ulva pertusa, Enteromorpha prolifera and Monostroma grevillei was amplified, sequenced and analyzed. By comparing the rbcL sequences with seven other Ulvales species retrieved from GenBank, the sequence divergences and the phyletic evolution were analyzed and the phylogenetic tree was constructed. From the phylogenetic tree, it can be found that U. pertusa, E. prolifera and U. californica group in one branch, while E. compressa, U. rigida and U. fenestrata cluster in another clade. Obviously, unlike the Enteomorpha species, the Ulva species do not gather in one branch. Therefore Ulva and Enteomorpha might be affiliates of one genus. E. compressa and E. intestinalis gathered together, which coincided with the morphological characters. However, the thallus of U. pertusa is thick and with many holes, which is different from E. prolifera in morphology. They cluster together in the phylogenetic tree with a genetic distance of 0.005. The results indicate that Ulva and Enteromorpha are not distinguished strictly.

There is confusion about the identity of laminar Ulva thalli in Italian and Mediterranean transitional systems and on the open coasts. Although some authors report the presence of both U. rigida and U. laetevirens, systematic revisions for the Adriatic and Mediterranean Seas recognise only the presence of U. laetevirens. This paper uses anatomical and environmental analyses to provide evidence for the presence of both species. The only diagnostic character that distinguishes the two is cell shape in cross section of rhizoidal and basal regions. Therefore, identification of floating thalli in these regions is not possible. The species grow and coexist in the same environments and on the same substrata, but analysis of environmental data suggests that U. rigida occurs preferentially in eutrophic environments, especially lagoon areas rich in phosphate, ammonium and phytoplankton, whereas U. laetevirens is more abundant in areas where nutrient levels are low.

Synthesis and accumulation of molecular chaperones are universal responses found in all cellular organisms when exposed to a variety of unfavorable conditions. Heat shock protein 70 (Hsp70), which is one of the major classes of molecular chaperones, plays a particularly important role in cellular stress responses, and the Hsp70 system is the most intensely studied in higher plants and algae. Therefore, we isolated and characterized a cDNA clone encoding Hsp70 from a sterile strain of Ulva pertusa (Ulvales, Chlorophyta). The sterile U. pertusa Hsp70 (UpHsp70) cDNA consisted of 2,272 nucleotides and had an open reading frame encoding a polypeptide of 663 amino acid (AA) residues with a molecular mass of 71.7 kDa. Amino acid alignment and phylogenetic analysis of Hsp70s from other organisms showed that UpHsp70 was more similar to cytoplasmic Hsp70s from green algae and higher plants (or =75%) than to those from other algae and microorganisms. Southern blot analysis indicated that the sterile U. pertusa genome had at least four cytoplasmic Hsp70-encoding genes. UpHsp70 mRNA levels were significantly affected by diurnal changes, rapidly increased by high-temperature stress, and gradually increased by exposure to copper, cadmium, and lead. These results suggest that UpHsp70 plays particularly important roles in adaptation to high-temperature conditions and diurnal changes, and is potentially involved in tolerance to heavy metal toxicity.

The systematics of the green algal class Ulvophyceae have been difficult to resolve with ultrastructural and molecular phylogenetic analyses. Therefore, we investigated relationships among ulvophycean orders by determining the distribution of two discrete genetic characters previously identified only in the order Dasycladales. First, Acetabularia acetabulum uses the core translation GTPase Elongation Factor 1alpha (EF-1alpha) while most Chlorophyta instead possess the related GTPase Elongation Factor-Like (EFL). Second, the nuclear genomes of dasycladaleans A. acetabulum and Batophora oerstedii use a rare non-canonical genetic code in which the canonical termination codons TAA and TAG instead encode glutamine. Representatives of Ulvales and Ulotrichales were found to encode EFL, while Caulerpales, Dasycladales, Siphonocladales, and Ignatius tetrasporus were found to encode EF-1alpha, in congruence with the two major lineages previously proposed for the Ulvophyceae. The EF-1alpha of I. tetrasporus supports its relationship with Caulerpales/Dasycladales/Siphonocladales, in agreement with ultrastructural evidence, but contrary to certain small subunit rRNA analyses that place it with Ulvales/Ulotrichales. The same non-canonical genetic code previously described in A. acetabulum was observed in EF-1alpha sequences from Parvocaulis pusillus (Dasycladales), Chaetomorpha coliformis, and Cladophora cf. crinalis (Siphonocladales), whereas Caulerpales use the universal code. This supports a sister relationship between Siphonocladales and Dasycladales and further refines our understanding of ulvophycean phylogeny.

SUMMARY The macroalgal species Ulva limnetica Ichihara et Shimada was investigated to understand the molecular mechanism of its tolerance or adaptation to freshwater. We detected a 19 kDa protein by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which accumulated in greater amounts in freshwater conditions compared with marine conditions. The band was excised and the partial amino acid sequence was determined by Edoman degradation. Based on the sequences, we isolated the corresponding cDNA by the rapid amplification of cDNA ends (RACE) technique. The constructed, full-length cDNA was 1272 bp in length, consisting of 198 bp 5′-non-coding region, an open reading frame of 840 bp (279 amino acids), 233 bp 3′-non-coding region and poly (A) tail. The protein encoded by the cDNA showed 30% identity and 45% similarity to lectin isolated from Ulva pertusa Kjellman, and we named this gene ULL (encoding Ulva limnetica lectin-like protein). Northern blot analysis demonstrated that the expression level of the ULL in the freshwater-cultured sample was higher than in the seawater-cultured sample.

SUMMARY Ulva limnetica Ichihara et Shimada, sp. nov. (Ulvales,Ulvophyceae) is described from the Ryukyu Islands,Japan, and is characterized by thalli that are: (i)branched, tubular, fragile and wrinkled; (ii) up to 80 cmin height and up to 2 cm in diameter; (iii) light toyellowish green in color; and (iv) having an asexualreproduction by means of quadriflagellate swarmers.Rhizoidal cells bear tubular extensions on the outsideof the cell layer in the stipe. Ulva limnetica is distin-guished from species with similar thalli by chloroplastdisposition, branching pattern, number of pyrenoidsper cell and gross morphology. It is also distinguishedby sequences of the nuclear-encoded 18S ribosomalRNA gene, internal transcribed spacer 2 region andthe plastid-encoded large subunit of ribulose-1,5-bisphosphate carboxylase/oxgenase gene ( rbc L). Ulvalimnetica was clustered with other Ulva species in anearly diverging lineage within the genus.Key words: molecular phylogeny, morphology, rbc L,taxonomy

Hormones are present in seaweeds, but little is known about their biosynthesis and regulation. The aim of this study was to investigate variation in concentration and composition of endogenous cytokinins, auxins and abscisic acid in two seaweeds collected over a 1 year period to gain a more complete picture of the types of hormones present during a range of environmental and developmental conditions. Ulva fasciata (Ulvales, Chlorophyta) and Dictyota humifusa (Dictyotales, Phaeophyta) were collected bimonthly from the inter-tidal zone at Rocky Bay, South Africa. Ethanol extracts of the samples containing a mixture of internal standards were purified using a combined DEAE-Sephadex-octadecylsilica column, followed by immuno-affinity chromatography and analysed by high-performance liquid chromatography–mass spectrometry to quantify different cytokinins, auxins and abscisic acid. cis-Zeatin, isopentenyladenine and their ribotide and riboside conjugates were the main cytokinins present in both U. fasciata and D...

A homogeneous sulfated heterorhamnan was obtained by aqueous extraction, then by ultrafiltration from the green seaweed Gayralia oxysperma. Besides α-l-rhamnose it contains glucuronic and galacturonic acids, xylose and glucose. The structure was established by methylation analyses of the carboxyl-reduced, carboxyl-reduced/desulfated, carboxyl-reduced/Smith-degraded, and carboxyl-reduced/Smith-degraded/desulfated products and 1D, 2D NMR spectroscopy analyses. The heterorhamnan backbone is constituted by 3- and 2-linked rhamnosyl units (1.00:0.80), the latter being ∼50% substituted at C-3 by side chains containing 2-sulfated glucuronic and galacturonic acids and xylosyl units. The 3- and 2-linked rhamnosyl units are unsulfated (20%), disulfated (16%), and mostly monosulfated at C-2 (27%) and C-4 (37%). The branched and sulfated heterorhamnan had high and specific activity against herpes simplex virus. Fil: Cassolato, Juliana E. F.. Universidade Federal do Paraná; Brasil Fil: Noseda, Miguel D.. Universidade Federal do Paraná; Brasil Fil: Pujol, Carlos Alberto. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Pellizzari, Franciane M.. Universidade Federal do Paraná; Brasil Fil: Damonte, Elsa Beatriz. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Duarte, Maria E. R.. Universidade Federal do Paraná; Brasil

Gametes of the marine green alga Ulva compressa L. are biflagellate and pear shaped, with one eyespot at the posterior end of the cell. The species is at an early evolutionary stage between isogamy and anisogamy. In the past, zygote formation of green algae was categorized solely by the relative sizes of gametes produced by two mating types (+ and -). Recently, however, locations of cell fusion sites and/or mating structures of gametes have been observed to differ between mating types in several green algae (asymmetry of cell fusion site and/or mating structure positions). To use this asymmetry for determining gamete mating type, we explored a new method, field emission scanning electron microscopy (FE-SEM), for visualizing the mating structure of U. compressa. When gametes were subjected to drying stress in the process of a conventional critical-point-drying method, a round structure was observed on the cell surfaces. In the mating type MGEC-1 (mt(+) ), this structure was located on the same side of the cell as the eyespot, whereas it was on the side opposite the eyespot in the mating type MGEC-2 (mt(-) ). The gametes fuse at the round structures. TEM showed an alignment of vesicles inside the cytoplasm directly below the round structures, which are indeed the mating structures. Serial sectioning and three-dimensional construction of TEM micrographs confirmed the association of the mating structure with flagellar roots. The mating structure was associated with 1d root in the MGEC-1 gamete but with 2d root in the MGEC-2 gamete.

Based on samplings during 2006-2007 on the intertidal zone of Playa Tampico, Erendira and Punta Baja, Baja California, Ulva pertusa Kjellman (Ulvales, Chlorophyta) was recorded for the first time for the Pacific coast of Mexico. An alga native to Asia, U. pertusa has just recently been recorded in the southern coast of California (USA). The identification of U. pertusa was based on the observation of the morphology and reproductive characters of the collected specimens. Furthermore, the species identity was confirmed by molecular comparison between nuclearencoded ITS2 sequences of the Mexican samples and those of other Ulva species in GenBnak data. Habitat and distribution of U. pertusa along the Pacific coast of North America are also described. Considering our new report of its occurrence in Mexico, we conclude that U. pertusa is expanding its geographical distribution by trans-ocean introductions.

Intracellular acid phosphatase activity has been detected in the marine macroalga Ulva rigida. Cytochemical experiments conducted in vegetative cells evidenced the presence of the reaction product adjacent to or along the plasma- lemma, within cytoplasmic vesicles and associated with different vacuolar inclu- sions such as vesicles and multivesicular bodies. This observation leads to infer that acid phosphatases are part of a system through which the orthophosphate anion is obtained from phosphate esters.

Ulva pertusa Kjellman (Ulvales, Chlorophyta), which is widely distributed in the Pacific Ocean, has been detected on the NW Atlantic coast of the Iberian Peninsula (Galicia, Spain). The material has lobed and perforated blades, without marginal teeth, and with characteristic wrinkling at the base; it has an average thickness of 150 μm in the upper basal zone. Cells have a single chloroplast with (1-) 2 (-3) pyrenoids and, in surface view, show only local ordering. In transverse sections, cells are squarish or oblong, with rounded corners. Blades have a wide fertile margin with cells containing up to 28 gametes. The species-level identification as U. pertusa was confirmed by molecular studies (rbcL sequence analysis). This is the first report for this opportunistic species from the Iberian Peninsula. Its introduction is probably attributable to the importation of biological material for shellfish culture.

Frequent occurrences of green tides caused by Ulva species (Ulvales, Ulvophyceae) associated with eutrophication along enclosed coasts are currently causing environmental problems in coastal ecosystems. In addition, increasing intercontinental introductions of coastal marine organisms, including Ulva, are also a serious issue. However, due to the considerable morphological plasticity of this genus, the taxonomy of Ulva species based on morphological studies is problematic. Therefore, in order to elucidate the species diversity and seasonal changes of the dominant Ulva species in Mikawa Bay, central Honshu, Japan, we made seasonal collections of Ulva species at seven localities, and identified the dominant species using the ITS2 rDNA region sequences. We identified the following nine taxa as common Ulva species in the area: 1) Ulva pertusa Kjellman; 2) U. ohnoi Hiraoka et Shimada; 3) U. linza L.; 4) U. californica Wille; 5) U. flexuosa Wulfen; 6) U. fasciata Delile; 7) U. compressa L.; 8) U. armoricana Dion et al.; 9) U. scandinavica Bliding. Among the species, U. pertusa was most common and dominant from spring to summer, and U. ohnoi from autumn to winter. Ulva californica and U. scandinavica have not been reported before from Japan.

The production of dimethylsulfoniopropionate (DMSP) and its cleavage products are well studied in phytoplankton. However, less is known about their sources, distributions, functions, and impacts in other marine organisms. We examined the distribution of DMSP in benthic macroalgae and macroinvertebrates geographically and taxonomically. In macroalgae, concentrations significantly increased from the tropics to the poles in the northern, but not the southern, hemisphere. The increase in the northern hemisphere was due to an increase in concentrations with latitude in the Chlorophyta. This pattern was generated by a relatively high proportion of species in the order Ulvales (median [DMSP]: 145 μmol g-1 dry mass (DM)) at higher latitudes, and a high proportion of species in the orders Caulerpales and Siphonocladales (median [DMSP]: below detection level for both orders) in the tropics. Low DMSP concentrations (< 10 μmol g-1 DM) were reported from all red and brown macroalgae, except Polysiphonia and Halopytis. In macroalgae, some of the reported functions of DMSP and its cleavage products included acting as a compatible solute, an anti-herbivore defense, a reactive oxygen scavenger, and a cryoprotectant. Among macroinvertebrates, DMSP occurred in higher concentrations in cnidarians than in sponges and molluscs. Concentrations in animals harboring endosymbiotic algae were 6.5 times higher than animals without symbionts. This and direct measurements of DMSP from isolated symbionts suggest that endosymbionts are a major source of DMSP for some macroinvertebrates. Diet may be a source of DMSP in animals that lack endosymbionts. The functions and impacts of DMSP in invertebrates are not well known.

Heteroglycan and xyloglucan rich fractions were extracted from Indian samples of Enteromorpha compressa in 25% yield by sequential extractions with water and alkali. This heteroglycan is sulfated and has an apparent molecular mass of 55 kDa. Chemical structural analysis of this polysaccharide revealed a branched structure having 1,4- and 1,2,4-linked rhamnose 3-sulphate, 1,4-linked glucose, 1,3- and 1,6- linked galactose, 1,4- and terminally linked glucuronic acid and 1,4-linked xylose partially sulfated on O-2. Chemical and spectroscopic analysis showed that the 4-M KOH extracted hemicellulosic fraction contained an unusual β-(1,4)-linked linear xyloglucan. Enzyme hydrolysis and analysis of the resulting fragments by matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) showed that this linear polymer contained partially sulfated Glc3Xyl2 or Glc4Xyl2 as oligomeric building subunits.

Green macroalgae, such as Ulvales, lose their typical morphology completely when grown under axenic conditions or in the absence of the appropriate microbiome. As a result, slow growing aberrant phenotypes or even callus-like morphotypes are observed in Ulvales. The cross-kingdom interactions between marine algae and microorganisms are hence not only restricted by the exchange of macronutrients, including vitamins and nutrients, but also by infochemicals such as bacterial morphogenetic compounds. The latter are a fundamental trait mediating the mutualism within the chemosphere where the organisms interact with each other via compounds in their surroundings. Approximately 60 years ago, pilot studies demonstrated that certain bacteria promote growth, whereas other bacteria induce morphogenesis; this is particularly true for the order of Ulvales. However, only slow progress was made towards the underlying mechanism due to the complexity of, for example, algal cultivation techniques, and the lack of standardized experiments in the laboratory. A breakthrough in this research was the discovery of the morphogenetic compound thallusin, which was isolated from an epiphytic bacterium and induces normal germination and restores the foliaceous morphotypes of Monostroma. Owing to the low concentration, the purification and structure elucidation of highly biologically active morphogenetic compounds is still challenging. Recently, it was found that only the combination of two specific bacteria from the Rhodobacteraceae and Flavobacteriaceae can completely recover the growth and morphogenesis of axenic Ulva mutabilis cultures forming a symbiotic tripartite community by chemical communication. This review combines literature detailing evidence of bacteria-induced morphogenesis in Ulvales. A set of standardized experimental approaches is further proposed for the preparation of axenic algal tissues, bacteria isolation, co-cultivation experiments, and the analysis of the chemosphere.

Specifically in Piedade reef, where we performed the present study, Isognomon bicolor invasive bivalve showed greater abundance in the mid intertidal band before dominated by the bivalve Brachidontes solisianus and the barnacle Tetraclita stalactifera. However, the abundance and size structure of Isognomon bicolor and Brachidontes solisianus are variable in the local collection related to desiccation and the presence of Ulva spp.. In this context, this study aims to evaluate the population structure of Isognomon bicolor and Brachidontes solisianus from density and shell length data. For that, were randomly collected 3 quadrats of 20 X 20 cm in February and May 2012, dry and rainy seasons respectively. The animals were scraped, and placed in labeled plastic bags, and frozen for later sorting. After sorting the length of the bivalve shells were measured with the aid of caliper, the seaweed Ulva spp. was also screened, dried and weighed. The Chi-Square test was used to assess the difference between the frequency distribution of the different size classes. The bivalves were divided into 10 size classes. The chi-square test detected a significant difference between the population structure of bivalves. Isognomon bicolor had lower density in May 2012 during the drought, while more individuals Brachidontes solisianus were found in May. However the largest proportion of individuals was always between 13-16 mm in both months of collection for Isognomon bicolor and 3 mm for Brachidontes solisianus presenting both bivalve unimodal distribution these sizes could be more resistant to desiccation and predation stress. The Mann-Whitney test showed a lower density for Ulva spp. in May 2012.

A new freshwater species of Ulvella, U. tongshanensis H. Zhu et G. Liu, is described from material collected from rocks under small waterfalls in Hubei Province, China. This unusual species differs from other species in the genus by the macroscopic and upright parenchymatous thalli, and by the particular habitat (most Ulvella species occur in marine environments). Phylogenetic analyses of plastid encoded rbcL and tufA, and nuclear 18S rDNA sequences, pointed towards the generic placement of U. tongshanensis and also showed a close relationship with two other freshwater species, Ulvella bullata (Jao) H. Zhu et G. Liu, comb. nov. and Ulvella prasina (Jao) H. Zhu et G. Liu, comb. nov. The latter two were previously placed in the genus Jaoa and are characterized by disc-shaped to vesicular morphology. Our study once again shows that traditionally used morphological characters are poor indicators for phylogenetic relatedness in morphologically simple algae like the Ulvellaceae. Thus, the morphological circumscription of the genus Ulvella is here expanded to include: (1) thalli that are uniseriate in basal and apical parts, and parenchymatous in the middle portion with distinct differentiation of an unbranched dorsal side and a ventral side developing many short branches, and (2) epibiotic or epilithic, disc-shaped to vesicular thalli with a di- or tristromatic structure.

This study investigated the ecology and growth of Monostroma nitidum Wittrock in both its natural habitat and the laboratory. The maximum length, width, and weight of M. nitidum in March were 9.04.7 cm, 9.63.6 cm, and 1.521.13 g, respectively. Yellowish-green or yellowish-brown reproductive thalli began to appear in January, and over 80% of the thalli matured by March. The male and female spores were ca. 6 m long, and elongate and ovoid in shape. The spores had two flagella and one-eye spot, and tended to swim toward light. Maximum number of spores released from matured thalli was 236 cells/mL after 70 minutes at a light intensity of 100 mol/m/s. The zygote diameter ranged from 3.4-6.0 m (mean 4.2 m) and increased to 69.8 m 14 weeks after culture. The mass release of zoospores was observed from thalli in the dark (3 to 12 days), after 30 min under dry conditions in the shade, at 25, and a light intensity of 100 mol/m/s. The maximum number of zoospores released was 109.8 cells/mL after 60 min of induction. M. nitidum fronds on the net increased to 6.8-7.2 cm in length, and 6.6-8.9 cm in width during the winter.

SUMMARY We cultured and sequenced newly collected material of Percursaria dawsonii Hollenberg et I. A. Abbott, a poorly known epibiont of limpets found along the west coast of North America. Zoospores, parthenogametes, and zygotes exhibited empty-spore germination, which produced a prostrate system that expanded by stolon-like development. A dense carpet of initially uniseriate filaments arose from the prostrate system. These upright filaments soon became biseriate proximally and pluriseriate distally, where they were flat, twisted and distromatic for approximately four-fifths of their length and rarely became hollow in larger individuals. These fronds became fertile distally and released quadriflagellate zoospores and/or biflagellate isogametes. Individual gametophytic fronds were dioecious, and alternated with isomorphic sporophytic fronds. The gametes moved rapidly and often exhibited an unusual side-to-side vibration that made them appear like winged insects. Comparisons of 18S rRNA gene and ITS sequences indicated that P. dawsonii should be included in the genus Blidingia, family Kornmanniaceae.

For plants and algae UVB radiation represents an important stress factor associated with sunlight. This radiation has the potential to inhibit physiological processes like photosynthesis as well as to damage molecules like the DNA. In plants adaptation to UVB radiation is based on two main resistance mechanisms: physical screening or cellular tolerance. The main goal of this thesis was to investigate to which extent and how precisely these strategies are present in different representatives of green macroalgae. For the first time UV screening was discovered in the order Cladophorales and the connected photoprotective function could be demonstrated in UVB challenge experiments. In contrast the majority of the remaining orders did not exhibit UV screening and was analyzed for the alternative resistance mechanisms like photosystem II (PS II) repair and DNA repair capacities. Especially species from the very abundant and often highlight exposed genus Ulva had an outstandingly high UVB tolerance of PS II. Field experiments corroborated the high potential of cellular UVB tolerance mechanisms in Ulva intestinalis.

SUMMARY Cellular pH estimated from cell extract pH, and the ion compositions of major inorganic ions (Na+, NH4+, K+, Mg2+, Ca2+, Cl−, Br−, NO3−, S042-) were studied by ion chromatography in 15 species of 4 orders (Cladophorales, Codiales, Siphonocladales and Ulvales) of Ulvophyceae and 49 species of 8 orders (Bangiales, Ceramiales, Corallinales, Cryptonemiales, Gelidiales, Gigartinales, Nemaliales and Rhodymeniales) of Rhodophyceae. Among the Rhodophyceae, relatively low intracellular pH (approximately 2.0 within cells) and high concentration of S042- was demonstrated in Plocamium telfairiae(Harvey) Harvey. Furthermore, five species of Hypnea Lamouroux were shown to contain high concentrations of S042- balanced by relatively high concentrations of Na+. Among the Ulvophyceae, Codium cylindricum Holmes and Ulva pertusa Kjellman contained high concentrations of S042- balanced by relatively high concentrations of Mg2+.

Temporal and spatial changes in the coverage of five Ulva L. species (U. prolifera O.F. Müller, U. intestinalis L., U. hookeriana (Kützing) Hayden et al., U. compressa L. and U. linza L.) were analyzed on rocky substrata experimentally immersed in Comodoro Rivadavia Harbor (Argentina). Colonization was studied during an annual period at three levels: upper intertidal, middle intertidal and subtidal. Coverage was significantly higher in the middle intertidal and subtidal levels than in the upper intertidal level, where all species of Ulva were absent. Seasonal changes were also significant: coverage in summer and spring was significantly higher than in autumn and winter. Most species showed high spatial variability among replicates from the same level and season. Zonation patterns within the harbor differed from those observed in natural areas, probably due to low wave exposure and its interaction with herbivory and desiccation stress. Colonization patterns observed in this study indicate nichesegregation in closely related species of the genus Ulva.

SUMMARY The green macroalgal genus Ulva (incl. Entemmorpha) contains economically valuable species, is of relevance for coastal management (green tides), and certain taxa serve as experimental organisms for fundamental research in green algae. The nuclear genome size of Ulva (Entemmorpha) compressa Linnaeus was measured in propidium iodide stained nuclei using laser scanning cytometry. Nuclei of fixed gametes yielded reproducible values, whereas nuclei extracted from multicellular gametophytes were unsuitable. With nuclei of Arabidopsis thaliana (L.) Heynh and Saccharomyces cerevisiae Hansen as references, the haploid nuclear genome size of U. compressa was calculated as 135 ± 7 Mbp. This is the smallest genome so far known from any species of Ulva.

Species delineation in the genus Ulva is difficult due to a lack of distinguishing morphological characters and the high degree of phenotypic plasticity observed in these algae; thus, species descriptions are necessarily based on a limited set of characters. The present study uses molecular data to test species hypotheses for and explore species diversity in Ulva in the northeast Pacific. Samples of 21 taxa were collected from Valdez, Alaska to San Diego, California, additional Pacific locales outside this region, and Europe. Sequences from ITS nrDNA and the rbcL gene were analysed separately and simultaneously using maximum parsimony to reconstruct phylogeny. Molecular data resolve many of the species recognized by early and more recent treatments, reveal unanticipated potentially conspecific taxa and suggest that certain Ulva species are more widely distributed than may have been recognized previously. At least 12 species of Ulva were found in the northeast Pacific based on the present data: Ul...

We constructed a cDNA library from sterile Ulva pertusa (Ulvales, Chlorophyta), and isolated and characterized a full-length cDNA clone encoding actin. The actin (ACT) cDNA consisted of 1487 nucleotides (nt) and had an open reading frame (ORF) encoding a polypeptide of 377 amino acid (AA) residues. The ACT gene had one intron in the 5'-untranslated region and three introns in the coding region. Transcription started 26 nt downstream of the putative TATA box. A potential polyadenylation signal, TGTAG, was located 100 nt downstream of the terminator codon, TAG. Amino acid alignment with actins from various algae and land plants showed that sterile U. pertusa actin was more similar to actins from Chlorophyta, Phaeophyta, Euglenophyta, and higher plants (over 76.9%) than to actins from Rhodophyta. Southern blot analysis indicated that the sterile U. pertusa genome has only a single actin-encoding gene. Thalli grown on a 12D/12L photoperiod increased in surface area some two-fold over 24 h regardless of the nutritional conditions. The growth rate of thalli during the light period was significantly higher than that during the dark period. Northern hybridization indicated that the expression of actin mRNA was induced and repressed by the light and dark treatments, respectively. These results suggest that the U. pertusa cell division cycle has a periodicity of 24 h and that the ACT gene is highly transcribed during cell growth and development in the light period.

SUMMARY Ulva ohnoi Hiraoka et Shimada sp. nov. (Ulvales, Ulvophyceae) is described from southern and western Japan and is characterized by the following combination of features: (i) the large, fragile, easily torn thalli, which are 30–55 μm thick in the upper and middle regions and often have microscopic marginal teeth; (ii) the production of zoids in the upper marginal region; (iii) a regular alternation of dioecious gametophytes and a sporophyte; (iv) the production of free-floating thalli from torn-off attached thalli, which reproduce vegetatively by fragmentation and form green tides in summer to autumn; (v) disorderly arranged cells that are polygonal or quadrangular in the upper and middle regions; and (vi) the chloroplast covering the outer face of cell, with 1–3 pyrenoids. Ulva ohnoi differs from U. armohcana Dion et al., U. fasciata Delile, U. reticulata Forsskal, U. scandinavica Eliding and U. spiulosaOkamura et Segawa, which all possess microscopic marginal serrations, in thallus shape, cell shape or life history pattern. It is also distinguished from morphologically similar species by sequences of the nuclear encoded internal transcribed spacers and the 5.8S ribosomal RNA gene and the plastid encoded large subunit of ribulose-l,5-bisphosphate carboxylase/oxgenase gene. Furthermore, crossing tests demonstrate that there is a reproductive boundary between U. ohnoi and the most closely related species, U. fasciata and U. reticulata.

Aspects of the reproduction of Bolbocoleon piliferum N. Pringsheim, a common, small, filamentous, endophytic marine green alga, were examined by LM and TEM. These observations were combined with phylogenetic analysis of nuclear-encoded small subunit rRNA gene sequences to assess the phylogenetic position of B. piliferum. Quadriflagellate zoospores and planozygotes derived from fusion of isogametes yielded plants with identical morphology. Zoosporangia and gametangia divided by sequential cleavages. Plugs at the apices of zoosporangia and gametangia formed during development; tubes were found at zoosporangial and gametangial apices after swarmer release. Flagellar apparatuses of zoospores and gametes were similar to those of algae in the Ulvales (Ulvophyceae), except that terminal caps were entire rather than bilobed and rhizoplasts and "stacked" microtubular root configurations were absent. Structures associated with planozygotes were identical to those observed in other algae currently assigned to Ulotrichales and Ulvales. Molecular phylogenetic analyses placed B. piliferum within the Ulvophyceae, at the base of a clade that contains representatives of the families Ulvaceae, Ulvellaceae, and Kornmanniaceae. The results support an earlier hypothesis that B. piliferum constitutes a distinct lineage. Analyses including Kornmanniaceae recover mono'!' phyletic Ulotrichales and Ulvales, whereas analyses omitting the Kornmanniaceae indicate that Ulotrichales is paraphyletic. The structures associated with gamete fusion are conserved within Ulotrichales and Ulvales and perhaps more widely within Chlorophyta.

Ulva spp. are common in the intertidal zones of the Philippines, but, at certain times, could over-proliferate producing blooms or `green tide' in some protected bays. In Mactan Island (Cebu), central Philippines, at least two species constitute the Ulva population, either as free-living or attached form. The one referred to in the literature as `Ulva lactuca' mainly consists of free-living population while the species referred to as Ulva reticulata consists mainly of attached population. Based on morphological and physiological characteristics, `U. lactuca' differs much from the descriptions of the species from its type locality in Europe in having a crumpled texture of blade, presence of tooth-like protuberances at the margins, thinner thallus (40–50 μm) and more pyrenoids per cell (two to four). The species referred to as `U. lactuca' in the Philippines therefore is a different species. Two morphotypes consisted the `U. lactuca' population from Mactan – a thick thallus and a thin thallus type. However, both morphotypes cultured under the same condition in the laboratory could transform into the same thin-thallus type observed in the field. `Green tide' caused by `U. lactuca' occur almost regularly in Station 1 of Mactan Island, reaching an average biomass of up to 2.6 kg wet wt m−2 (or 0.5 kg dry wt m−2). Ulva reticulata, although was less abundant in the rocky tidal zone at most times, reaching an average biomass of only up to 0.15 kg wet wt m−2 (or 0.03 kg dry wt m−2) had caused green tide in Station 2 around February–March. Reproductive structures were not observed in both Ulva species during the survey period suggesting that vegetative fragmentation is the main mode of propagation. Vegetative tissues excised from the thallus can be induced to release biflagellated large and small zooids.

Populations of Enteromorpha prolifera collected from four rivers on Shikoku Island in Japan had three different types of life history. One type was the typical sexual life history of Enteromorpha, ...

Systematic hypotheses for the Ulvaceae were tested using phylogenetic analysis of sequences for the gene encoding the large subunit of RUBISCO, small subunit rDNA and a combined data matrix. Representatives of eight putative ulvaceous genera and twelve additional taxa from the Ulvophyceae and Trebouxiophyceae were included in analyses using maximum parsimony and maximum likelihood criteria. Molecular data supported hypotheses for the Ulvaceae that are based on the early development of vegetative thalli and motile cell ultrastructure. Ulvaceae sensu Floyd and O'Kelly, including Percursaria Bory de Saint-Vincent, Ulvaria Ruprecht and a complex of closely related species of Chloropelta Tanner, Enteromorpha Link and Ulva L. was supported; however, monophyly of Enteromorpha and Ulva was not supported. The Ulvales and Ulotrichales sensu Floyd and O'Kelly were monophyletic. Blidingia Kylin and Kornmannia Bliding were allied with the former and Capsosiphon Gobi with the latter, although relationships among these and other taxa in these orders remain uncertain. The Ulvales are characterized by an isomorphic life history pattern, gametangia and sporangia that are identical in structure and development, motile cells with bilobed terminal caps and proximal sheaths consisting of two equal subunits. Method of motile cell release and the gross morphology of vegetative thalli are not systematically reliable characters.

Although most members of the genus Enteromorpha are important edible green algae, some species are also potentially economically valuable crops. Samples of E. prolifera were obtained from the Yoshino River estuary, Tokushima, Japan and cultured in laboratory conditions at 10°C, a salinity of 20 psu, under white light with 12 h light : 12 h dark cycle and at a photon fluence rate (PFR) of 40 mmol/m 2 per s for 30 days. In the present study, the effect of salinity and PFR on the induction of reproductive cells and rhizoid formation were investigated. Synchronous formation of swarmers by thalli was induced in excised disks of 1.2 mm diameter after 2-5 days incubation. The optimum salinity for maturation of reproductive cells was between 5.0 and 52.0 psu, and between 13.2 and 45.3 psu for swarmer release, although the lower limit for swarmer release was 5.0 psu. Maturation of reproductive cells and swarmer release required a PFR higher than 16 mmol/m 2 per s. The minimum PFR for swarmer release was 8 mmol/m 2 per s. Many rhizoids were formed between 1.6 and 52.0 psu and photon fluence rates between 8 and 320 mmol/m 2 per s. Rhizoids were formed in a polarized manner.

The use of bioindicators for contaminant monitoring ispopular in all sectors of the environment but quite oftenbioindicators are utilised without rigorous evaluation oftheir viability as an indicator. We report field andlaboratory investigations into the value of a commonlyfound macroalga, Enteromorpha flexuosa (Wulfen) J.Agardh (Chlorophyta: Ulvales) as an indicator of copper,zinc and lead contamination in a tropical estuary inFiji. In the laboratory, metal content of E.flexuosa after 60 days of growth in seawater containingincreasing concentrations of the metals showed almostperfect correlation with metal concentrations in waterfor all three metals, and concentration factors obtainedwere generally higher than values reported for otherspecies of Enteromorpha. Performance in the fieldwas evaluated by a one-year monitoring of metals in E. flexuosa, water and sediments from a contaminatedestuary. Metal concentrations in water were always belowdetection limits and field concentration factors couldnot be determined but the concentration of lead in E. flexuosa showed a high correlation with the leadcontent of sediments. Lack of such correlation forcopper and zinc in the field suggests that otherenvironmental factors besides metal load in the physicalenvironment could be controlling the bioaccumulation ofthese two metals. Whilst demonstrating E. flexuosato be a viable bioindicator for lead, these results alsohighlight the need for proper assessment before anorganism is considered for environmental monitoring.

Ulva intestinalis and Ulva compressa are two bloom-forming morphologically-cryptic species of green seaweeds widely accepted as cosmopolitan in distribution. Previous studies have shown that these are two distinct species that exhibit great morphological plasticity with changing seawater salinity. Here we present a phylogeographic assessment of tubular Ulva that we considered belonging to this complex collected from various marine and estuarine green-tide occurrences in a ca. 600 km stretch of the Indian west coast. Maximum Likelihood and Bayesian Inference phylogenetic reconstructions using ITS nrDNA revealed strong endemism of Indian tubular Ulva, with none of the Indian isolates forming part of the already described phylogenetic clades of either U. compressa or U. intestinalis. Due to the straightforward conclusion that Indian isolates form a robust and distinct phylogenetic clade, a description of a new bloom-forming species, Ulva paschima Bast, is formally proposed. Our phylogenetic reconstructions using Neighbor-Joining method revealed evolutionary affinity of this new species with Ulva flexuosa. This is the first molecular assessment of Ulva from the Indian Subcontinent.

The kinetics of ammonium assimilation were investigated in two seaweeds from northeastern New Zealand, Enteromorpha sp. (Chlorophyceae, Ulvales) and Osmundaria colensoi (Hook. f. et Harvey) R.E. Norris (Rhodophyceae, Ceramiales), with the use of a recently developed method for measuring assimilation. In contrast to ammonium uptake, which was nonsaturable, ammonium assimilation exhibited Michaelis–Menten kinetics in both species. Maximum rates of assimilation (Vmax) were 27 and 12 μmol·(g DW)−1·h−1 for Enteromorpha sp. and O. colensoi, respectively, with half-saturation (Km) constants for assimilation of 18 and 41 μM. At environmentally relevant concentrations, assimilation accounted for all of the ammonium taken up by both species. The maximum rate of assimilation in Enteromorpha sp. resembled very closely that of the ammonium assimilatory enzyme, glutamine synthetase, when activities of the latter were measured in the presence of subsaturating substrate (glutamate and ATP) concentrations. Moreover, the initial rate of glutamine production (measured with HPLC) following ammonium enrichment was almost identical to the rates determined above. The rate of ammonium assimilation was therefore determined by three independent methods, two of which involve in vivo measurements, and it is suggested that the use of assimilation kinetics may be useful when examining the nutrient relations of seaweeds.