Macroalgae Ulva Pertusa Research Articles

Antifouling steroids isolated from red alga epiphyte filamentous bacterium Leucothrix mucor

Active antifouling steroids were isolated from the filamentous bacterium Leucothrix mucor. Bioactivity-guided isolation by silica gel column chromatography and high-performance liquid chromatography generated two compounds. The chemical constituents having the antifouling activities were identified as 17-(1,2-dihydroxyl-5-methyl-hexane)-2,3-dihydroxyl-cholest-4-en-6-one [compound (a)] and 13-acetate-17-(1,5-dimethylhexane)-cholest-7-en-3,5,6,15-tetraol [compound (b)] by interpreting one- and two-dimensional nuclear magnetic resonance and mass spectroscopy data. The two compounds were isolated from 780 mg of crude extract, yielding 12 and 14 mg, respectively. Antifouling activities were determined against a representative soft fouling macroalgae (Ulva pertusa), a biofouling diatom (Navicula annexa), and the bacteria Pseudomonas aeruginosa KNP-3 and Alteromonas sp. KNS-8. The two compounds were able to inhibit the spore settlement of Ulva pertusa zoospores with a low half maximal effective concentration (EC50) (1.2–2.1 μg/ml) and inhibit diatom growth with an EC50 of 5.2–7.5 μg/ml. Compound (a) showed activity with minimum inhibitory concentration values of 32–56 μg/ml and compound (b) showed an activity of 66–90 μg/ml. Among the two compounds, compound (a) is a new compound, whereas compound (b) was previously reported to have been isolated from a marine invertebrate.

Ecotoxicological effects of brine discharge on marine community by seawater desalination

To determine ecotoxicological effects of brine discharge from the desalination plant and the potential tolerance impact associated with various marine communities, marine ecotoxicological assessment was carried out using four phytoplankton species (Skeletonema coastatum, Chlorella vulgaris, Tetraselmis suecica and Isochrysis galbana) and macroalgae (Ulva pertusa) as primary producer, and two zooplankton species (neonate for rotifer Brachinonus plicatilis, adult of harpacticoid copepod Tigriopus japonicus) and one demersal fish (olive flounder, Paralichthys olivaceus) as consumers. Values of 72 h EC50 of population growth inhibition (PGI) for S. costatum, C. vulgaris, T. suecica and I. galbana were estimated as 55.1, 61.7, 56.9 and 42.2 ppt, respectively, and I. galbana was the most sensitive to brine. No significant differences in brine sensitivity were found in the ranges of 30.0–45.0 ppt for S. costatum and T. suecica, and less than 40.0 ppt for I. galbana. Mortality rates of B. plicatilis neonate and a...

The potential for utilizing fouling macroalgae as feed for abalone Haliotis discus hannai

In order to assess the potential of utilizing fouling macroalgae as feed for abalone Haliotis discus hannai, the species, biomass and total stock of fouling macroalgae attached on the aquaculture facility-lines were investigated and assessed at Sungo Bay, China, in August 2007. The nutritional value of four fouling macroalgae (Codium fragile, Sargassum muticum, Ulva pertusa and Laminaria japonica) and one cultured macroalgae (Gracilaria lemaneiformis) as the diet of abalone was assessed by analysis of the chemical composition of the macroalgae and by measuring bioavailability and digestibility to abalone H. discus hannai under laboratory conditions in August 2007. The results showed that the biomass of fouling macroalgae at the two sites was 243.61 ± 26.23 and 1078.15 ± 50.28 g m−1 respectively. The contents of protein of G. lemaneiformis and C. fragile were 18.30% and 17.60%, respectively, which were significantly higher than the others. The five macroalgae were accepted by the abalone, and growth energies (P) and growth efficiency (%) were positive. However, significant differences were found among the different macroalgae. The growth efficiencies of abalone show a negative relationship with the levels of dietary lipid and a positive relationship with the protein contents. These results suggest that fouling macroalgae have a great potential to be used as diets of abalone.

Allelopathic inhibition on red tide microalgae Skeletonema costatum by five macroalgal extracts

This study aims to identify effective antialgal allelochemicals from marine macroalgae that inhibit the growth of red tide microalgae. Practically, new algicidal agents were developed to control red tide. The growth inhibitory effects of 5 marine macroalgae Porphyra tenera, Laminaria japonica, Ulva pertusa, Enteromorpha clathrata, and Undaria pinnatifida on Skeletonema costatum were evaluated by adding crude seawater extracts of macroalgal dry tissue into the culture medium containing S. costatum. The half-effective concentrations at 120 h (EC50, 120 h) of the seawater extracts were 0.6, 0.9, 1.0, 1.0, and 4.7 g/L for the five macroalgae above, respectively. E. clathrata, L. japonica and U. pertusa showed strong allelopathic effect on the growth of S. costatum. There have been no previous reports with regard to the allelopathic effects of the former two macroalgae so far. The possible allelochemicals of 21 compounds of the E. clathrata were detected using Gas chromatography-mass spectrometry (GC-MS) analysis. Unsaturated fatty acids, acrylic acid (C3H4O2), and linolenic acid (C18H30O2) were the most likely allelochemicals in E. clathrata.

A novel marine algal toxicity bioassay based on sporulation inhibition in the green macroalga Ulva pertusa (Chlorophyta)

A 5-day aquatic toxicity test based on sporulation inhibition of the green macroalga Ulva pertusa Kjellman has been developed. Optimal test conditions determined for photon irradiance, salinity and temperature were 60–200 μmol photons m −2 s −1, 25–35‰ and 15–20 °C, respectively. Tests were conducted by exposing U. pertusa thallus disks to a reference toxicant (sodium dodecyl sulfate; SDS), metals (Cd 2+, Cu 2+, Zn 2+, Pb 2+) and elutriates of sludge collected from nine different locations. The EC 50 values for SDS was 5.35 mg L −1. When four heavy metals were assayed, the NOECs were highest for lead (0.625 mg L −1) and lowest for copper (0.031 mg L −1). The EC 50 values showed the following toxicity rankings: Cu 2+ (0.061 mg L −1) > Cd 2+ (0.326 mg L −1) > Zn 2+ (0.738 mg L −1) > Pb 2+ (0.877 mg L −1). The bioassay indicated also that the sporulation endpoint could be a sensitive indicator of toxicity effects of elutriates of sludge as reflected from the NOEC values equal to or lower than the lowest concentration employed (6.25%). Sporulation was significantly inhibitied in all elutriates with the greatest and least effects observed in elutriates of sludge from industrial waste (EC 50 6.78%) and filtration bed (EC 50 15.0%), respectively. The results of the Spearman rank correlation analysis for EC 50 data versus the concentrations of toxicants in the sludge presented a significant correlation between toxicity and four heavy metals (Cd 2+, Cu 2+, Pb 2+, Zn 2+). Introduction of the concept of toxicity unit (TU) showed that these metals were the main cause of toxicity in elutriates of at least four out of nine sludge samples. Members of the order Ulvales show a wide geographic distribution and have similar reproductive characteristics, thus making it possible to apply the present test method to other algae of this taxa, elsewhere. This novel method will be a useful tool for assessing the aquatic toxicity of a wide range of toxicants, once the respective sensitivities are demonstrated.

UV‐B INDUCTION OF UV‐B PROTECTION IN ULVA PERTUSA (CHLOROPHYTA)1

The green macroalga Ulva pertusa Kjellman produced UV‐B absorbing compounds with a prominent absorption maximum at 294 nm in response only to UV‐B, and the amounts induced were proportional to the UV‐B doses. Under a 12:12‐h light:dark regime, the production of UV‐absorbing compounds occurred only during the exposure periods with little turnover in the dark. There was significant reduction in growth in parallel with the production of UV‐B absorbing compounds. The polychromatic action spectrum for the induction of UV‐B absorbing compounds in U. pertusa exhibits a major peak at 292 nm with a smaller peak at 311.5 nm. No significant induction was detected above 354.5 nm, and radiation below 285 nm caused significant reduction in the levels of UV‐B absorbing compounds. After UV‐B irradiation at 1.0 W·m−2 for 9 h, the optimal photosynthetic quantum yield of the samples with UV‐B absorbing compounds slightly increased relative to the initial value, whereas that of thalli lacking the compounds declined to 30%–34% of the initial followed by subsequent recovery in dim light of up to 84%–85% of the initial value. There was a positive and significant relationship between the amount of UV‐B absorbing compounds with antioxidant activity as determined by the α,α‐diphenyl‐β‐picrylhydrazyl scavenging assay. In addition to mat‐forming characteristics and light‐driven photorepair, the existence and antioxidant capacity of UV‐B absorbing compounds may confer U. pertusa a greater selective advantage over other macroalgae, thereby enabling them to thrive in the presence of intense UV‐B radiation.

Allelopathic growth inhibition of Prorocentrum micans (Dinophyta) by Ulva pertusa and Ulva linza (Chlorophyta) in laboratory cultures

Allelopathic effects of several concentrations of fresh tissue and dry powder of two bloom-forming green macroalgae Ulva pertusa and Ulva linza on the red tide microalga Prorocentrum micans were investigated in coexistence culture systems. Preliminary studies on the algicidal effects of one aqueous and four organic solvent extracts from the macroalgae on the microalga were carried out to confirm the existence of allelochemicals in the tissue of these two macroalgae. The effects of filtrate of used macroalgal culture medium were tested on P. micans using a single initial or semi-continuous filtrate addition. Furthermore, the potential effects of the microalga on these two macroalgae were also evaluated. The results of the coexistence experiments demonstrated that the growth of P. micans was strongly inhibited by the addition of both the fresh tissue and the dry powder of both species of Ulva. Aqueous and methanol extracts of both macroalgae had strong growth inhibitory effects on P. micans, while the other three organic solvent extracts (acetone, ether and chloroform) had no apparent effect on its growth. This suggests that the allelochemicals from both macroalgae had relatively high polarities. The filtrate of used macroalgal culture medium exhibited no apparent growth inhibitory effect on the microalga under initial filtrate addition whereas the growth of P. micans was significantly inhibited under semi-continuous filtrate addition, which suggested that continuous release of small quantities of rapidly degradable allelochemicals from the fresh tissue of both macroalgae was effective in inhibiting the growth of P. micans. In contrast, the microalga had no apparent effect on the growth of either macroalgal species in coexistence experiments.

Litter dynamics and particulate organic matter outwelling from a subtropical mangrove in Okinawa Island, South Japan

Litter dynamics and outwelling of particulate organic matter (POM) was investigated in a subtropical mangrove (Okinawa Island, South Japan) in order to quantify the impact of mangrove POM on adjacent intertidal sediments. A distinct seasonal pattern was found with maximum litter fall during the autumn season, and minimum during winter. Total litter production between sites did not differ significantly. Tall mangroves (average 7 m) did not show any higher contribution to the litter production than short mangroves (average 4 m). The mean annual litter production was 12.95 ± 2.95 t ha −1 (dry weight) with leaf fall contributing more than 70% of the total litter production. Analysis of fatty acids (FAs) in the surface sediments of an adjacent mud flat and sand flat during the winter, spring and autumn seasons indicated that outwelling of POM from the mangrove ecosystem occurs. However, it is spatially restricted to within 300 m from the mangrove forest. The magnitude of the outwelling increased during spring and autumn consistent with the increase in the total litter production. Despite the presence of mangrove-derived organic matter in the estuarine surface sediments, autochthonous sources of organic matter, green macroalgae ( Ulva pertusa and Enteromorpha intestinalis), diatoms and bacteria are the main contributors of sedimentary organic matter and ω3 and ω6 PUFAs than mangrove-derived (POM) during winter and spring. While the contribution of mangrove-derived POM to sedimentary organic matter is limited to the autumn season.

Allelopathic interactions between the macroalga Ulva pertusa and eight microalgal species

Growth of Ulva pertusa and eight microalgal species, Heterosigma akashiwo, Skeletonema costatum, Tetraselmis subcordiformis, Nitzschia closterium, Chaetoceros gracile, Chroomonas placoidea 1967, Isochrysis galbana 8701, and Alexandrium tamarense, was examined in a series of batch, semi-continuous and isolated co-cultures ( U. pertusa and one microalgal species). The results of the experiments with co-cultures confirmed the secretion of allelopathic substances by U. pertusa. Growth was significantly ( p<0.05) suppressed in each of the macroalgal species in batch co-cultures, nutrient replete semi-continuous co-cultures and isolated co-cultures. The percentage growth reduction varied between 42 and 100% in batch co-cultures, between 28 and 100% in semi-continuous co-cultures, and between 21 and 100% in isolated co-cultures. In addition, we examined the potential allelopathic effect of U. pertusa culture filtrate. The Ulva culture filtrate significantly ( p<0.01) inhibited the growth of C. placoidea from 2 days after incubation until the end of the experiment, and it exhibited no inhibitory effect on the growth of the other microalgal species. This may suggest that the allelochemicals released from U. pertusa are rapidly degradable. The microalgae tested exhibited different (stimulatory, inhibitory or no) effects on the growth of U. pertusa. U. pertusa grew faster with H. akashiwo (+16%) and S. costatum (+9%), less with T. subcordiformis (−20%), N. closterium (−23%) and C. gracile (−30%), but was not significantly affected by I. galbana, A. tamarense and C. placoidea. The microalgae tested exhibited no clear allelopathic effects on U. pertusa.

Comparative studies on phosphorus uptake and growth kinetics of the microalga Tetraselmis subcordiformis and the macroalga Ulva pertusa

Short-term uptake experiments and long-term semicontinuous culture experiments were performed under the condition of phosphorus (P) limitation to estimate and compare the P uptake and growth kinetics of the microalga Tetraselmis subcordiformis and the macroalga Ulva pertusa. Two new parameters, the maximum specific uptake rate (Vmsp) and the maximal growth efficiency (β), are introduced to achieve uniformity for the comparison of nutrient uptake and growth efficiency between microalgae and macroalgae. T. subcordiformis possesses 3 times lower half saturation uptake constant, 4 times higher maximal growth rate and 20 times higher maximum specific uptake rate than U. pertusa, while U. pertusa possesses 4 times higher maximal growth efficiency than T. subcordiformis.

Preliminary study on the responses of three marine algae, Ulva pertusa (Chlorophyta), Gelidium amansii (Rhodophyta) and Sargassum enerve (Phaeophyta), to nitrogen source and its availability

An experiment was designed to select economically valuable macroalga species with high nutrient uptake rates. Such species cultured on a large scale could be a potential solution to eutrophication. Three macroalgae species, Ulva pertusa (Chlorophyta), Gelidium amansii (Rhodophyta) and Sargassum enerve (Phaeophyta), were chosen for the experiment because of their economic values and availability. Control and four nitrogen concentrations were achieved by adding NH 4 + and NO 3 − . The results indicate that the fresh weights of all species increase faster than that of control after 5 d culture. The fresh weight of Ulva pertusa increases fastest among the 3 species. However, different species show different responses to nitrogen source and its availability. They also show the advantage of using NH 4 + than using NO 3 − . U. pertusa grows best and shows higher capability of removing nitrogen at 200µmolL−1, but it has lower economical value. G. amansii has higher economical value but lower capability of removing nitrogen at 200 µmolL−1. The capability of nitrogen assimilation of S. enerve is higher than that of G. amansii at 200µmolL −1, but the former’s increase of fresh weight is lower than those of other two species. Then present preliminary study demonstrates that it is possible to use macroalgae as biofilters and further development of this approach could provide biologically valuable information on the source, fate, and transport of N in marine ecosystems. Caution is needed should we extrapolate these findings to natural environments.

Comparative studies on the allelopathic effects of two different strains of Ulva pertusa on Heterosigma akashiwo and Alexandrium tamarense

Allelopathic effects of fresh tissue and dry powder of a nonsexual and a sexual strain of the macroalga Ulva pertusa on the growth of the microalgae Heterosigma akashiwo and Alexandium tamarense were evaluated using long-term coexistence culture systems in which several concentrations of macroalga fresh tissue and dry powder were used. The effects of macroalga culture medium filtrate on the two HAB algae were also investigated. Moreover, isolation co-culture systems were built to confirm the existence of allelochemicals and preclude the growth inhibition by direct contact. Short-term algicidal effect assays of macroalgae on H. akashiwo were carried out to measure the rate of algal cell lysis. The results of the coexistence assays showed that the growth of H. akashiwo and A. tamarense was strongly inhibited by fresh tissue and by dry powder of both strains of U. pertusa. The allelochemicals were lethal to H. akashiwo at relatively higher concentrations. The macroalga culture medium filtrate exhibited no apparent growth inhibitory effect on the two HAB algae under initial or semicontinuous filtrate addition, which suggested that continuous release of small quantities of rapidly degradable allelochemicals from the fresh tissue of both strains of U. pertusa was essential to effectively inhibit the growth of H. akashiwo and A. tamarense.

NaOCl produced by electrolysis of natural seawater as a potential method to control marine red-tide dinoflagellates

As part of the development of a method to control the outbreak and persistence of red tides using sodium hypochlorite (NaOCl), we investigated the effect of NaOCl on the survival of red-tide dinoflagellates, diatoms, heterotrophic protists, planktonic crustaceans, fin-fish, shellfish, and macroalgae. Because NaOCl introduced into natural waters would be subject to dilution, as well as breakdown in sunlight to NaCl, the survival of organisms was determined after 10 min exposure and 1 h exposure to NaOCl, and again after transfer to fresh seawater for 6 or 24 h. The lethal total residual chlorine (TRC) concentration that killed 50% of the test organisms (LC50) for the red-tide dinoflagellates Gymnodinium catenatum, Cochlodinium polykrikoides, Akashiwo sanguinea, Lingulodinium polyedrum, Prorocentrum micans, Alexandrium affine, and Gymnodinium impudicum ranged from 57 to 157 ppb for 10 min exposure and from 30 to 106 ppb for 1 h exposure. Complete mortality of all red-tide species occurred at TRC concentrations of ~ 500 ppb. The LC50 of the diatoms Skeletonema costatum and Thalassiosira rotula, 3083–3383 ppb for 10 min exposure and 3128–3433 ppb for 1 h exposure, were much higher than for red-tide dinoflagellates. But the LC50s of the heterotrophic dinoflagellates Polykrikos kofoidii and Oxyrrhis marina were similar to those of red-tide dinoflagellates. The ciliate Strombidinopsis sp. had LC50s of 306 ppb for 10 min exposure and 119 ppb for 1 h exposure, which are higher than those for dinoflagellates. The LC50s of the calanoid copepods Acarlia spp. and Pseudodiaptomus sp. were 1397–1493 ppb for 10 min exposure and 744–987 ppb for 1 h exposure, and those for larvae of the brine shrimp Artemia franciscana were 4905 ppb for 10 m exposure and 2814 ppb for 1 h exposure. The LC50s of juvenile gray mullet Mugil cephalus and juvenile black rockfish Sebastes schlegeli were 1234–1883 ppb for 10 min exposure and 1234–1440 ppb for 1 h exposure, whereas those of adult Manila clam Ruditapes philippinarum and spat of the abalone Nordotis discus were> 20,000 ppb. The LC50s of the macroalgae Griffithsia japonica (Rhodophyta) and Ulva pertusa (Chlorophyta) were 1519–12,365 ppb for 10 min exposure and 1085–12,558 ppb for 1 h exposure. The present study therefore suggests that, if NaOCl is introduced into waters containing red-tide organisms at TRC concentrations of 300–500 ppb for 10 min exposure and 200–400 ppb for 1 h exposure, red tides can be effectively controlled without serious harmful effects on other marine organisms, except heterotrophic dinoflagellates.

A Rapid and Sensitive Method for Determination of Relative Specificity of RuBisCO from Various Species by Anion-Exchange Chromatography

A rapid and sensitive method to determine the relative specificity (r) of ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO) using anion-exchange chromatography is described. We employed the open gas system for the reaction of RuBisCO to get the most reliable CO2 and O2 concentrations in the reaction mixture. 3-Phosphoglycerate and 2-phosphoglycolate which were formed in the RuBisCO reaction were completely separated and directly measured with anion-exchange chromatography without using radioisotopes. The determination of the r value was accomplished in 3 h. The r values of RuBisCO enzymes from higher land plants were between 90 and 96, and those from bacteria including cyanobacterium were close to 45. These values were in agreement with previously reported values. The enzyme of the red macroalga Porphyra yezoensis exhibited a r value of over 140, as expected from the reported value of the enzyme from the red microalga Porphyridium cruenteum. RuBisCO from the green macroalga Ulvapertusa had a rvalue close to 70 and similar to that of the enzyme from the green microalga Chlamydomonas reinhardtii.