Dinucleotide microsatellite markers in the genus <Emphasis Type="Italic">Caulerpa</Emphasis>

Caulerpa spp. are clonal green marine algae which often act as invasive species when growing outside their native biogeographical borders. Over the two past decades, Caulerpa taxifolia has spread along the Mediterranean coast, presently occurring at 70 sites and covering nearly 3,000 ha of subtidal area. New genetic markers (microsatellites) have been developed to assess clonal structure and genetic diversity of recently established populations of the invasive species C. taxifolia and Caulerpa racemosa in comparison with populations of the native Caulerpa prolifera in the Mediterranean. Our results show that nine polymorphic markers have been developed for C. prolifera, seven for C. taxifolia, and three for C. racemosa. Genetic diversity in Caulerpa was assessed in two geographical scales: one at a population scale where 40 thalli units were collected from C. prolifera in Cala d’Or, Mallorca, Spain, and another at a species scale, where 30 sample units were analyzed for C. prolifera, 24 for C. taxifolia, and 24 for C. racemosa from different sites in the Mediterranean, Atlantic, and Pacific Ocean. Number of alleles, expected heterozygosity, and marker amplification success are provided in each case.     

Larvicidal effects of some natural products on the Aedes aegypti mosquito,a vector of dengue fever and Zika virus

Natural products are considered a good choice in the biological control of mosquitoes because they are an effective way to eliminate larvae and prevent an increase in mosquito numbers, while simultaneously not polluting the environment or damaging health. This investigation was designed to study the potential toxicity of three species of algae, Caulerpa racemosa (Weber-van Bosse, 1909), Padina boryana (Thivy, 1966), and Turbinaria ornata (Turner J. Agardh, 1848), on the larvae of Aedes aegypti mosquito, the vector of dengue and Zika viruses. Among the studied species, Caulerpa racemosa showed the greatest effectiveness in eradicating A. aegypti larvae with an LC₅₀ = 43.5 ppm, followed by Padina boryana with an LC₅₀ = 51.93 ppm. Both species proved to be excellent candidates as a source of larvicidal agents and could be used commercially in mosquito control programs as eco-friendly biopesticides. The combined activity of different mixtures against mosquito larvae was expressed as the coeffective factor (C.F.). C.F. values showed that the joint activity of insect growth regulator Dudim in combination with Caulerpa racemosa and Padina boryana extracts produced degrees of potentiation effects and degrees of additive effects were obtained with Dudim in combination with Turbinaria ornata extract.     

Caprellid assemblages (Crustacea: Amphipoda) in shallow waters invaded by <Emphasis Type="Italic">Caulerpa racemosa</Emphasis> var. <Emphasis Type="Italic">cylindracea</Emphasis> from southeastern Spain

Growth of the invasive algae Caulerpa racemosa var. cylindracea in shallow habitats may influence the faunal assemblage composition. We studied its effects on caprellid assemblages associated with shallow-water habitats of hard and soft bottoms from the SE Iberian Peninsula (native rocky-bottom algae, C. racemosa from hard and soft bottoms, and Caulerpa prolifera, Cymodocea nodosa and Posidonia oceanica from soft bottoms). Samples were taken in two different sampling periods (September 2004 and March 2005). A total of seven caprellid species were identified, with important differences in their distribution in different habitats. Total abundance of caprellids was very high in March on native algae on hard bottoms, and on C. racemosa on both soft and hard bottoms. On both hard and soft bottoms, abundances of Caprella hirsuta recorded from C. racemosa were low. On the other hand, a higher abundance of other species, namely C. acanthifera, C. santosrosai, Phtisica marina and Pseudoprotella phasma, was recorded from C. racemosa. The results indicate that C. racemosa may have a positive influence on some caprellid species, while seasonal changes are also evident. It is concluded that introduced C. racemosa may serve as a new habitat, promoting and maintaining caprellid populations in shallow Mediterranean habitats.     

Antioxidant response and caulerpenyne production of the alien Caulerpa taxifolia (Vahl) epiphytized by the invasive algae Lophocladia lallemandii (Montagne)

Invasive algae alter the structure and function of ecosystems. The red algae Lophocladia lallemandii grows in the West Mediterranean epiphyting the green algae Caulerpa taxifolia, another invasive alga. Our aim was to determine whether the invasive algae Lophocladia, recently introduced in the West Mediterranean, induces oxidative stress and an antioxidant response in Caulerpa taxifolia. We measured the caulerpenyne production, the activities of antioxidant enzymes and the levels of markers of lipid peroxidation in Caulerpa taxifolia. Caulerpenyne concentration was significantly higher in Caulerpa taxifolia epiphytized by Lophocladia. End-products of lipid peroxidation -malondialdehyde (MDA) and 4-hydroxinonenal (4-HNE)- were significantly increased in Caulerpa taxifolia samples from the station with Lophocladia. Antioxidant enzyme activities -catalase and superoxide dismutase (SOD)-, as well as H₂O₂ production significantly increased in the Lophocladia station compared to the control station. The activities of catalase and SOD determined in Lophocladia lallemandii showed no significant differences between Lophocladia living alone and Lophocladia epiphytating Caulerpa taxifolia. Caulerpa taxifolia epiphytized by Lophocladia lallemandii responded by increasing the caulerpenyne and H₂O₂ production and the antioxidant enzymes activities as a defensive mechanism against the new invasive algae.     

Phytotoxic activity of caulerpenyne from the Mediterranean invasive variety of Caulerpa racemosa: a potential allelochemical

Allelopathy has been postulated as a factor in the colonisation success of Caulerpa racemosa var. cylindracea, an introduced chlorophyte alga which has become invasive in the Mediterranean Sea. In order to reveal their possible phytotoxic activity, secondary metabolites were isolated from a population growing in the Gulf of Naples (Italy) and tested on leaf tissue of the native seagrass Cymodocea nodosa, which often co-occurs with Caulerpa in nature. The seaweed metabolites were identified by ¹H and ¹³C NMR analysis and leaf portions of C. nodosa were exposed to crude diethyl ether extract and purified compounds in the laboratory, under controlled conditions of irradiance and temperature for a period of 144 h. Eventual changes in the photosynthetic performance of the seagrass tissue following the treatment were tested by monitoring its optimal quantum yield with a pulse amplitude modulated (PAM) fluorometer. One of the identified compounds, caulerpenyne, showed a phytotoxic effect, while the other purified metabolites did not reveal any effect at the assayed concentrations. Thus, our results seem to suggest a possible allelopathic activity of caulerpenyne, which may play a role in the successful competition of the invasive C. racemosa var. cylindracea with native macrophytes, such as seagrasses.     

Antiproliferative and newly attributed apoptotic activities from an invasive marine alga: Caulerpa racemosa var. cylindracea

Caulerpa racemosa (Forsskål) is a green marine alga which spreads from tropical to warm-water regions. Due to having invasive capacity C. racemosa var. cylindracea is a well-known biological pollution in Mediterranean Sea. One of the most important secondary metabolites of C. racemosa is Caulerpenyne (CPN). In the present study, antiproliferative and apoptotic effects of C. racemosa var. cylindracea extract and purified CPN on two well-known neuroblastoma cell lines, SHSY5Y and Kelly, are investigated. The antiproliferative and, additionally, newly attributed apoptotic effects of both C. racemosa var. cylindracea extract and purified CPN on SHSY5Y and Kelly cell lines have been shown in the present study. IC₅₀ values are 0.59 ± 0.06; 1.06 ± 0.23 g wet alga/methanol and 5.64 ± 0.09; 6.02 ± 0.09 μM CPN for C. racemosa var. cylindracea extract and purified CPN on SHSY5Y and Kelly cell lines, respectively. Percentages of apoptotic cells of SHSY5Y and Kelly in 0, 0.1 and 1 μM CPN conditions were 1.00 ± 0.71, 3.00 ± 0.71 and 49.40 ± 3.78, 39.60 ± 6.19 and 78.00 ± 2.74, 69.40 ± 3.78, respectively. In conclusion, the present study shows the antiproliferative effect of C. racemosa var. cylindracea extract and newly attributed apoptotic effects of C. racemosa var. cylindracea this extract. Compared to other alkylating anticancer drugs, CPN and also C. racemosa var. cylindracea extract might be considered as an alternative native source of antitumor drugs. Inasmuch as both C. racemosa extract and CPN have shown both antiproliferative and apoptotic effects on SHSY5Y and Kelly cell lines, the CPN and CPN derivatives might be considered as multifunctional agents in cell metabolism.     

GENOMIC DNA ISOLATION FROM GREEN AND BROWN ALGAE (CAULERPALES AND FUCALES) FOR MICROSATELLITE LIBRARY CONSTRUCTION1

A method for isolating high‐quality DNA is presented for the green algae Caulerpa sp. (C. racemosa, C. prolifera, and C. taxifolia) and the brown alga Sargassum muticum. These are introduced, and invasive species in Europe, except for the native C. prolifera. Previous methods of extraction, using cetyl trimethyl ammonium bromide or various commercial kits, were used to isolate genomic DNA but either no DNA or DNA of very low quality was obtained. Genomic libraries were attempted with Caulerpa sp. on three occasions and either the restriction enzyme, the Taq polymerase, or the T4 ligase was inhibited, probably by the large amount of polysaccharides in these algae. The method presented here consists of the rapid isolation of stable nuclei, followed by DNA extraction. Yields of 6–10 μ g genomic DNA from 1 g fresh blades were obtained. After genomic DNA was isolated from fresh material, the quality was checked by agarose gel. Quantification of DNA concentration was performed using UV spectrophotometric measurement of the A ₂₆₀/ A ₂₈₀ ratio. The DNA was suitable for PCR, cloning, and hybridization. The DNA isolated using this method allowed successful construction of microsatellite libraries for Caulerpa species and S. muticum . The technique is inexpensive and appropriate for the isolation of multiple samples of DNA from a small amount of fresh material.     

Do native herbivores provide resistance to Mediterranean marine bioinvasions? A seaweed example

Generalist herbivores in marine ecosystems are poorly examined for their potential to serve as a source of biotic resistance against algal invasion. We assessed how one of the main generalist herbivores in Mediterranean rocky reefs (the sea urchin Paracentrotus lividus) affects Lophocladia lallemandii and Caulerpa racemosa, two algal invaders with strong detrimental effects on native benthic communities. In a comparison of sea urchin gut contents to algal community composition, strong preferences were exhibited, leading to no relationship between consumption and availability. Both C. racemosa and L. lallemandi were abundant in algal assemblages (>60% occurrence), but C. racemosa (20% of diet) was consumed more than L. lallemandi (3.5%). Experimental enclosures of sea urchins (12 sea urchins * m⁻²) were carried out in locations where L. lallemandii was already established and C. racemosa was rare (new invasion) or abundant (established invasion). C. racemosa was negatively affected by sea urchins only when it was rare, and no effect was detected when the alga was already abundant. Results for L. lallemandi were exactly opposite: urchins limited seasonal increases in L. lallemandi in highly-invaded areas. Because of the small amount of direct consumption of L. lallemandi, its decrease in abundance may be related to the grazing of native algae where L. lallemandii is attached. Overall, our results show that high densities of native herbivores may reduce invasive algae at low densities, due to a combination of direct and indirect effects, but it has no significant effect in highly-invaded areas.     

Invasive alga <Emphasis Type="Italic">Caulerpa racemosa</Emphasis> var. <Emphasis Type="Italic">cylindracea</Emphasis> makes a strong impact on the Mediterranean sponge <Emphasis Type="Italic">Sarcotragus spinosulus</Emphasis>

Here we present the first observation of the impact of the invasive Caulerpa racemosa var. cylindracea on native photophilic sponge species in the Adriatic Sea, with special focus on Sarcotragus spinosulus. Caulerpa racemosa var. cylindracea is able to completely overgrow the sponge, developing an exceptionally thick canopy with a maximum measured density of 1,887 m of stolons m⁻² and 40,561 fronds m⁻². Necrosis of the sponge surface was significantly correlated with the algal dry biomass, frond number and stolon length. Dense algal canopy, penetration of the algal stolon and rhizoids into the sponge oscula and covering of the ostiae probably diminishes the seawater circulation through the sponge and consequently results in its smothering and even death. We suggest that chemotropism is the reason why C. racemosa penetrates the sponge oscula and establishes such dense canopy on the sponge.     

Bioactive compounds from Caulerpa racemosa as a potent larvicidal and antibacterial agent

Marine algae are rich sources ofbioactive compounds capable of harboring secondary metabolites which are structurally and biologically active. In our study, the methanolic extract of marine algae Caulerpa racemosa （green algae） was employed to determine the antibacterial and larvicidal activity. The antibacterial activity showed effective inhibition against five pathogenic bacteria. A significant zone size of 16 mm was observed for Pseudomonas aeruginosa. The methanolic extract of Caulerpa racemosa showed effective larvicidal activity against Culex tritaeniorhynchus and the histopathological studies revealed the rupture in mid gut of larvae. The bioactive compounds in the crude extract were further identified as 2-（-3-bromo-1-adamantyl） acetic acid methyl ester and Chola-5, 22- dien-3-ol by GC-MS. Hence the bioactive compounds obtained from the methanolic extracts could be used for the bactericidal and larvicidal activity which will overcome the harmful impact of synthetic insecticide on environment.     

A FORENSIC AND PHYLOGENETIC SURVEY OF CAULERPA SPECIES (CAULERPALES,CHLOROPHYTA) FROM THE FLORIDA COAST,LOCAL AQUARIUM SHOPS,AND E‐COMMERCE: ESTABLISHING A PROACTIVE BASELINE FOR EARLY DETECTION1

Baseline genotypes were established for 256 individuals of Caulerpa collected from 27 field locations in Florida (including the Keys), the Bahamas, US Virgin Islands, and Honduras, nearly doubling the number of available GenBank sequences. On the basis of sequences from the nuclear rDNA‐ITS 1+2 and the chloroplast tufA regions, the phylogeny of Caulerpa was reassessed and the presence of invasive strains was determined. Surveys in central Florida and southern California of >100 saltwater aquarium shops and 90 internet sites revealed that >50% sold Caulerpa. Of the 14 Caulerpa species encountered, Caulerpa racemosa was the most common, followed by Caulerpa sertularioides, Caulerpa prolifera, Caulerpa mexicana, and Caulerpa serrulata. None of the >180 field‐collected individuals (representing 13 species) was the invasive strain of Caulerpa taxifolia or C. racemosa. With one exception (a sample of C. racemosa from a shop in southern California belonged to the invasive Clade III strain), no invasive strains were found in saltwater aquarium stores in Florida or on any of the internet sites. Although these results are encouraging, we recommend a ban on the sale of all Caulerpa species (including “live rock”) because: morphological identification of Caulerpa species is unreliable (>12% misidentification rate) and invasive strains can only be identified by their aligned DNA sequences, and because the potential capacity for invasive behavior in other Caulerpa species is far from clear. The addition of the Florida region to the genetic data base for Caulerpa provides a valuable proactive resource for invasion biologists as well as researchers interested in the evolution and speciation of Caulerpa.     

<Emphasis Type="Italic">Caulerpa racemosa</Emphasis> var. <Emphasis Type="Italic">cylindracea</Emphasis> as a potential source of organic matter for benthic consumers: evidences from a stable isotope analysis

Caulerpa racemosa var. cylindracea has been invading various types of substrates in wide areas throughout the Mediterranean Sea. However, the effects of the distribution of this alga on zoobenthos are scanty. The aim of this study was to evaluate the effects of C. racemosa invasion on the feeding habits of some zoobenthic taxa inhabiting the upper infralittoral rocky shores. This was done by identifying the isotopic N and C ratios of several potential food sources and testing differences in isotope composition among the taxa collected from areas invaded and not-invaded areas by C. racemosa. Results suggest that C. racemosa detritus was a significant food source for the polychaete Syllis prolifera, the gammarid Corophium sextonae and the gastropods Cerithium rupestre and Pisinna glabrata. They would also suggest that stable carbon and nitrogen isotope ratios deserve further attention as a possible valuable approach to understand the overall effect of C. racemosa spread on the trophic interactions among the species.     

Somatic cells serve as a potential propagule bank of <Emphasis Type="Italic">Enteromorpha prolifera</Emphasis> forming a green tide in the Yellow Sea,China

For the last 2 years, vast accumulations of the unattached filamentous green alga, Enteromorpha prolifera, have occurred during summer along the coastal region of the Yellow Sea, China. However, algae do not seem to occur after the end of the fertile season. It has been suggested that banks of microscopic forms of the algae, primarily spores, function as a survival mechanism for this opportunistic alga. Therefore, in this study, field surveys and laboratory cultures were conducted to determine if somatic cells were serving as a propagule bank to enable the algae to survive through periods of unfavorable conditions. Laboratory experiments demonstrated that somatic regeneration was one of the most important approaches by which E. prolifera colonized and flourished in the study area. Indeed, at least 19.32% of somatic cells from the filamentous segments could survive for 2 months under various temperatures (0, 5, 10, 15, 20, and 30°C at an irradiance of 60 μmol photons m⁻² s⁻¹) and irradiances (darkness, 5 10, 15, 20 and 30 μmol photons m⁻² s⁻¹ at a temperature of 20°C). Additionally, greater than 35.85% of the somatic cells could survive at 0°C or in darkness for 2 months, and no less than 15.99% of these cells resumed growth when the temperature and irradiance were adjusted to the normal levels (20°C and 60 μmol photons m⁻² s⁻¹). Furthermore, the results of field surveys revealed that viable E. prolifera was widespread in high quantities in the sediment of the Yellow Sea when the macroalga was absent. Taken together, the results of this study suggest that somatic cells may act as an overwintering stage for the annual spring bloom of E. prolifera. These findings should be useful in future studies conducted to behavior of somatic cells in green tide as well as in the management of future spring blooms of E. prolifera.     

Preliminary survey of toxicity of the green algaCaulerpa taxifolia introduced into the Mediterranean

Caulerpa taxifolia (Vahl) C. Agardh (Ulvophyceae, Caulerpales) is an alga of tropical origin that was accidentally introduced into the Mediterranean sea in 1984, where this species can reach an abundance that has never been described in tropical endemic regions. It is known that caulerpacean algae can develop an efficient strategy against grazers consisting of the synthesis of repulsive of toxic secondary metabolites: we report here the first study of the toxicity of purified secondary metabolites and raw extracts fromC. taxifolia from the Mediterranean.Toxicity was evaluated on three models: mice (lethality), mammalian cells in culture (cytotoxicity) and sea urchin eggs (disturbance of cell proliferation). Aqueous extracts are only active on fibroblasts and mice. In the three toxicity models a seasonal variation of toxicity is observed for the crude methanol extract as well as a decrease of this activity whenC. taxifolia from the Mediterranean is kept in aquaria. Pure compounds exhibit different toxicity depending on the assay. 10,11-epoxycaulerpenyne is the most active substance on mice and fibroblasts whereas taxifolial A and D are inactive or only weakly toxic. Among the four tested compounds caulerpenyne, the major metabolite ofC. taxifolia, is the most active on sea urchin eggs. Caulerpenyne may therefore represent an ecological risk for microorganisms and the eggs of multicellular animals living close to this alga. The ecological impact of this toxicity on marine organisms and the interaction of this alga with the herbivorous fauna are discussed.     

Invasion of alien macroalgae in different Mediterranean habitats

The study evaluated different macroalgal invasions in the main Mediterranean coastal habitats on hard bottom. Biodiversity, species composition and structure of macroalgal assemblages were compared among non-invaded areas and areas invaded by the Chlorophyta Caulerpa racemosa var. cylindracea and by the turf-forming Rhodophyta Womersleyella setacea in three different habitats: shallow rocky bottom, deep rocky bottom and dead matte of the seagrass Posidonia oceanica. Results showed that alien macroalgae constituted a relevant component of benthic assemblages in invaded areas of the Mediterranean Sea. Assemblages invaded by Womersleyella setacea and Caulerpa racemosa showed lower values of diversity and large differences in the structure and species composition related to non-nvaded assemblages. The species that mostly suffered from invasion were erect species reproducing sexually; moreover, the dominance of W. setacea led to low abundance of native filamentous algae, while C. racemosa colonization seemed particularly threatening for encrusting algae. All the studied habitats appeared highly invasible by alien macroalgae, even if W. setacea appeared more invasive in deeper habitats, while colonization of C. racemosa seemed more serious in shallower habitats; the dead matte of P. oceanica represented a suitable substrate for the spread of both species. Differences among assemblages in different habitats were reduced in invaded areas.     

Neurotoxic effect of <Emphasis Type="Italic">Caulerpa racemosa</Emphasis> var. <Emphasis Type="Italic">cylindracea</Emphasis> by neurite inhibition on the neuroblastoma cell line

In the present study, antiproliferative, apoptotic and especially neurotoxic effects of Caulerpa racemosa var. cylindracea dry and wet extracts on mouse neuroblastoma cell line, NA2B were investigated by neurotoxicity screening test (NST). C. racemosa var. cylindracea wet and dry extracts were obtained by methanol (MT) extraction. The effect of the extracts on viability and proliferation was measured by MTT. NA2B cells were induced to differentiate using 1 μM dcAMP and the amount of inhibition of growing neurites in different dilutions (50, 35, 25, 15, 10 and 5 μl/ml) by extracts was measured. The number of apoptotic cells was computed by TUNEL method using cells in culture. It was found that majority of the cells died with dry extract above the level of 15 μl/ml due to the MT effect. Below this level, on the other hand, presence of cell death and antiproliferative effect was noted due to the toxic effects of C. racemosa var. cylindracea which was independent of MT. In all doses of wet extracts, similar but less prominent dose-dependent effects were observed. Below the level of 15 μl/ml, mild toxic effect presented itself with neurite inhibition. In addition to the toxic, apoptotic and antiproliferative effects of C. racemosa var. cylindracea, its neurotoxic effects possessing property at low concentrations which manifesting itself by neurite inhibition was also showed. This species offers a potential for developing new drugs due to its antiproliferative, toxic and apoptotic effects. Nevertheless, its neurotoxic effect is a factor to be considered as multifunctional agents especially in neuronal metabolism.     

Effects of <Emphasis Type="Italic">Caulerpa racemosa</Emphasis> var. <Emphasis Type="Italic">cylindracea</Emphasis> on prey availability: an experimental approach to predation of amphipods by <Emphasis Type="Italic">Thalassoma pavo</Emphasis> (Labridae)

Alien plant species, such as Caulerpa racemosa var. cylindracea, that invade Mediterranean marine vegetated habitats can affect habitat structure. In turn, changes in habitat structure may affect the associated invertebrate assemblages, either through changes in habitat selection or as a result of altered predation efficiency. In order to test for effects of changes in habitat structure resulting from colonization by C. racemosa on prey availability for predators, the importance of amphipods as a trophic resource in natural vegetated habitat was first assessed, and later experiments were undertaken to assess the effects of the alien alga on predation by Thalassoma pavo of two dominant amphipods: Elasmopus brasiliensis (Gammaridea) and Caprella dilatata (Caprellidea). Laboratory experiments were conducted in separate aquaria with five vegetation habitat types: Halopteris scoparia, Jania rubens, C. racemosa without detritus, C. racemosa with detritus, Cymodocea nodosa, together with controls. The vegetation was first defaunated, and then 30 amphipods were introduced to each aquarium and exposed to a single Thalassoma pavo individual for 1 h, after which the fish’s gut contents were examined. Consumption (per fish per hour) of caprellids (11.7 ± 1.4) was higher overall than that of gammarids (8.7 ± 1.5) and likely reflects different microhabitat use by amphipods, which affects susceptibility to predators. Consumption of amphipods also varied by habitat type. The highest predation rate was found in the C. nodosa habitat (12.7 ± 2.19) and the lowest in the C. racemosa habitats with detritus (4.1 ± 1.78) and without detritus (5.2 ± 0.55), which did not differ. The pattern of predation across habitats, however, was similar for both caprellid and gammarid amphipods, indicating a more general effect of habitat on amphipod predation. Our findings showed that invasive species such as C. racemosa can decrease feeding by predators such as T. pavo. Changes in predator–prey interactions could have consequences for food web support in the Mediterranean.     

Culture studies onCaulerpa (caulerpales,chlorophyceae) III. Reproduction,development and morphological variation of laboratory-culturedC. racemosa var.peltata

Reproduction, development and morphological variation of the marine green algaCaulerpa racemosa var.peltata from the southern part of Japan were studied in culture in the laboratory. Anisogamous biflagellate male and female gametes were produced monoeciously and copulated with each other. Settled zygotes became spherical and increased in volume. After five weeks, they formed two germ tubes which extended in opposite directions. Both germ tubes became elongated and branched, resulting in the formation of creeping, filamentous, protonema-like plants. These plants formed primary shoots which differentiated into creeping rhizomes and upright axes. Each upright axis successively formed ramuli and developed into an assimilator. The morphology of assimilators, i.e., shape and arrangement of ramuli, varied with culture coditions. The effects of temperature and light intensity on the formation of assimilators were investigated with 25 combinations of 5 temperatures (20.0–30.0C) and 5 light intensities (0.5–8.0 klux). The morphological plasticity of this alga is identical to that ofCaulerpa racemosa var.laetevirens, which was previously described by the present authors. Thus, apparently, the plasticity of this taxon is correlated with environmental factors. It appears, moreover, thatC. racemosa var.peltata andC. racemosa var.laetevirens are ecophenes (ecads) of a single species.     

Lipoxygenase inhibition by novel fatty acid ester from Annona squamosa seeds

Studies on the seeds of Annona squamosa yielded a novel lipoxygenase inhibitor fatty acid ester, (+) - annonlipoxy (1). Compound 1 was screened for its enzyme inhibitory activity against lipoxygenase (E.C.1.14.18.1), exhibiting activity with IC₅₀ 69.05 ± 5.06 μm. Baicalein (IC₅₀ 22.6 ± 0.5 μm) was used as a positive control. Crude extracts of Annona squamosa fruit pulp and seeds were screened for its enzyme inhibitory activity against lipoxygenase and acetylcholinesterase. The crude ethanolic extract of fruit pulp and seeds of Annona squamosa also exhibited lipoxygenase activity with 22.2 and 26.7% inhibition, while the pet.ether extract of seeds of A. squamosa exhibited 52.7% inhibition at a concentration of 40 μg/200 ml. The crude ethanolic extract of seeds of Annona squamosa was also bioassayed for acetylcholinesterase inhibition and it was found inactive.     

Nutritional and bioactive properties of three edible species of green algae,genus Caulerpa (Caulerpaceae)

The green algae genus Caulerpa is coenocytic, and the thallus consists of only one cell with many nuclei. It is widely distributed in the tropical seas. In the Southeast Asian waters, there are at least ten known species. Three species, particularly Caulerpa racemosa var. clavifera f. macrophysa (Kützing) Weber-van Bosse, C. racemosa var. laetevirens (Montagne) Weber-van Bosse, and Caulerpa lentillifera J. Agardh are widely consumed. The proximate analysis and secondary metabolite composition of these three species were determined to describe their lipid and nutritional values. Glycolipids and phospholipids were the major lipid classes, with significant levels of triacylglycerol. Polyunsaturated fatty acids (PUFA) were the major fatty acids of all the three species. Typical n-3 and n-6 PUFA such as 18:3n-3, 18:4n-3, 20:5n-3, 18;2n-6, and 20:4n-6 were found in significant amount in all these three species. All three species contained a red-pigmented secondary metabolite determined as caulerpin. All three extracts exhibited potent antimicrobial activity against human food pathogenic bacteria and anti-inflammatory activity against the murine macrophage cell line, RAW 264.7.