Genus Caulerpa Research Articles

Structural characteristics of sulfated xylogalactomannan isolated from Caulerpa okamurae and its anticoagulant activity

Due to wonderful taste, rich nutrition and biological functions, many marine green algae in the genus Caulerpa have been recently developed as candidates for green caviar. A novel water-soluble sulfated xylogalactomannan CO-0-1 was obtained from the green algae Caulerpa okamurae. CO-0-1 was mainly composed of mannose (Man), galactose (Gal), and xylose (Xyl) at the ratio of 4.4:4.0:1.4 with the molecular weight at 470 kDa and the sulfate content at 12.78 %. The sulfated xylogalactomannan had Man at the backbone with →4)-β-D-Manp-(1→ and →2)-β-D-Manp-(1→ as the main chain and branches at O-3 position. The side chains contained →3)-β-D-Galp-(1→ and minor →2)-β-D-Xylp(1→. The sulfate groups only distributed at the side chains and at O-6 position of →3)-β-D-Galp-(1→ and O-4 position of (1→2)-β-D-Xylp. The anticoagulant activity indicated that CO-0-1 displayed intrinsic anticoagulant and specific anti-thrombin activities. The investigation expanded the utilization and development scene and scope of the green algae Caulerpa okamurae.

Use of Biomass from Beached Algae of the Genus Caulerpa to Obtain the Alkaloid Caulerpin

Caulerpin is an alkaloid with various biological activities, such as antinociceptive, anti-inflammatory, and antitumoral. This natural product is the majority in algae of the genus Caulerpa, which are found fixed to rocks on the seabed and beached to the sands. The objective of the research was to evaluate the possibility of using the biomass of these marginalized algae to obtain the alkaloid. Using ultrasound extraction and analysis by gas chromatography coupled with mass spectrometry, the results showed that it was possible to identify caulerpin in the beached algae. Furthermore, the alkaloid showed good resistance to photodegradation since caulerpin remained practically unchanged after 7 days of exposure to sunlight.

Exploring toxicological interactions in a changing sea: The case of the alkaloids caffeine and caulerpin

The bisindolic alkaloid caulerpin (CAU) is a bioactive compound isolated from green algae of the genus Caulerpa that are highly invasive in the Mediterranean Sea. On the other side, the purine alkaloid caffeine (CAF) is one of the most globally consumed psychoactive substances and a widespread anthropogenic water pollutant. Both compounds display a large panel of biological properties and are well known to accumulate in the tissues of aquatic organisms and, in certain circumstances, co-occur in the human diet. On this premise, the present study aimed to investigate possible synergistic interactions between CAU and CAF by using the bivalve Mytilus galloprovincialis as a model organism. Mussels were exposed to CAF via medium while they were fed with food enriched with CAU. After treatments, biochemical analysis confirmed the toxic potential of CAF, with increased AChE activity and lipid peroxidation. Also, histopathological alterations were observed in the gills and digestive tubules. The NMR-based metabolomics analysis detected higher levels of free amino acids under CAF treatments. Conversely, the food administration of CAU did not affect the above toxicological biomarkers. In addition, we did not observe any cumulative effect between CAF and CAU toward increased cellular damage and neurotoxicity. On the other hand, a possible action of CAU in decreasing CAF toxicity could be hypothesized based on our results. This hypothesis is supported by the activity of CAU as an agonist of peroxisome proliferator-activated receptors (PPARs). PPARs mediate xenobiotic detoxification via cytochromes P450, which is involved in CAF metabolism. Overall, the results obtained not only rule out any cumulative adverse effects of CAF and CAU but also encourage further research to evaluate the possible use of CAU, a compound easily obtained through the valorization of biomass from invasive species, as a food additive to improve the clearance of xenobiotics.

Biomass from Beached Algae of the Genus Caulerpa to Obtain the Alkaloid Caulerpin

Caulerpin is a molecule that has several biological activities that are extremely important and sought after in the pharmaceutical market. It is found in algae of the genus Caulerpa, mainly in the species Caulerpa racemosa. This species of algae can be found beached in the sand along the Baía de Todos os Santos (Salvador, Bahia, Brazil). This project aims to study the use of the biomass of these marginalized algae. We extracted and analyzed the algae collected alive to evaluate the presence of caulerpin and then continue the research and processing of data with beached algae. The results showed that caulerpin was identified in all extractions. Therefore, the method Caulerpa racemosafor extracting and analyzing caulerpin was optimized and could be used in beached algae later.

Structure, preparation, and biological activity of sulfated polysaccharides from the genus Caulerpa (Chlorophyta): A review

Structure, preparation, and biological activity of sulfated polysaccharides from the genus Caulerpa (Chlorophyta): A review

Possible Interactions between Invasive Caulerpa Taxa and Native Macrozoobenthos: The Case Study of Favignana Island

Biological invasions are widely recognized as a major threat to native biodiversity, ecosystem functioning and services. Amongst the NIS recorded in the Mediterranean Sea, Chlorophyta species belonging to the genus Caulerpa (Caulerpa cylindracea, C. taxifolia and C. taxifolia var. distichophylla) have raised serious concerns due to their potential or ascertained impact on native benthic communities. During surveys carried out to monitor the occurrence and the coverage of Caulerpa species along the coasts of Favignana Island (Egadi Islands Marine Protected Area), we observed variations in C. cylindracea and C. taxifolia coverage and also some large invertebrates overgrown with thalli of both species.

Range expansion and population shifts of estuarine fishes in a changing subtropical estuary

Catastrophic losses (ca. 95%) of seagrass and increased environmental degradation have occurred during the past decade in the Indian River Lagoon (IRL) estuary on the US Atlantic coast of Florida. Changes were observed in the abundance of 2 closely related sparid fishes in these estuarine waters based on fishery-independent monitoring efforts over 22 yr: sea bream Archosargus rhomboidalis significantly increased, while sheepshead A. probatocephalus simultaneously declined. These abundance trends and a northward expansion of sea bream into areas where they had never been documented were associated with an annual minimum water temperature increase of approximately 1.5°C, an annual mean water temperature increase of 0.9°C, and an annual mean salinity increase of 7.6 ppt. Lost seagrass habitat was often replaced by species belonging to the attached macroalgae genus Caulerpa or remained bare. Our findings suggest that sea bream, a tropical herbivore, are expanding poleward into the northern IRL, which may further negatively impact the potential recovery of sheepshead populations via competition. Furthermore, observed declines in seagrasses and populations of dependent species, including sheepshead, will likely continue if anthropogenic perturbations persist or expand. Long-term monitoring is essential for the timely detection of population changes and range shifts to better refine direct fisheries management of existing species and determine the potential need for management of recently expanding fish species should new fisheries emerge. Effective monitoring also allows for more proactive restoration of critical habitats and water conditions to minimize further adverse effects on fishes and other estuarine biota.

Exploring Metabolites Of Green Algae Caulerpa Spp. To Discover Putative Inhibitors Of Dpp-4, A New Antidiabetic Target Protein

Diabetes mellitus (DM) remains a serious global health threat, claiming a million lives every year and affecting nearly 9% of the adult population who suffer from this impaired insulin sensitivity disease. The Dipeptidyl peptidase-4 (DPP-4) enzyme has recently attracted attention because of its crucial role in insulin signaling, making this enzyme an interesting and emerging target for antidiabetic drug discovery. This study aimed to explore reported metabolites from marine algae of the genus Caulerpa as DPP-4 inhibitors through computational studies using CB-dock 2, Protein-Ligand Interaction Profiler, SwissAdme, and pkCMS. Molecular docking allowed the identification of 7 hit compounds with strong binding affinities (8.4 kcal to 9.3 kcal/mol) against DPP-4 target enzyme PDB ID: 3G4I. Four hits showed stronger binding affinity than two DPP-4 specific inhibitors and FDA-approved antidiabetic drugs, sitagliptin (8.4 kcal/mol) and linagliptin (9.0 kcal/mol). Following a molecular modification of the hit compounds using a bioisosterism-like approach and ADMET evaluation with pkCMS, three putative DPP-4 inhibitors were identified. They showed either stronger binding affinities or better ADMET profiles than sitagliptin and linagliptin, suggesting their promising potential as DPP-4 inhibitors. However, further optimized bioisoterism, in silico and in vivo studies, and clinical-based trials are required to confirm their antidiabetic activity. Keywords: Antidiabetic, Caulerpa racemosa, caulerpin, DPP-4

Phytochemical Screening and Antioxidant Activities of Some Seaweed from Kabung Island Waters West Kalimantan

Seaweed is one of the prima donna marine biota which is widely used as a natural antioxidant. Various species of seaweed are found growing naturally in the waters of Kabung Island, West Kalimantan. This study aims to determine the phytochemical content and antioxidant activity of each genus Turbinaria, Hypnea and Caulerpa from those collected in the waters of Kabung Island. Seaweed extraction uses maceration method with methanol to remove active compounds. Next, a phytochemical screening was performed using specific reagents such as alkaloids, steroids, flavonoids, tannins and saponins which will change color or form precipitates. The free radical scavenging method of 2,2-diphenyl-1-picrylhydrazyl (DPPH) solution was used to test the antioxidant activity of each seaweed extract. The active compound in the sample extract will be formed if there is a change in the color of free radicals from dark purple to light yellow or clean. The results showed that the phytochemical screening of the three seaweed extracts contained tannins, flavonoids and saponins. Meanwhile, positive alkaloids were found in Turbinaria and Caulerpa extracts, and steroids were indicated by the genus Hypnea and Caulerpa. Antioxidant screening showed that Caulerpa extract was categorized as a potent antioxidant with an IC50 value of 88.57 ppm, higher than the IC50 of Turbinaria and Hypnea extracts, which were 114.32 and 138.42 ppm respectively and classified as weak antioxidants.

Occurrence of opportunistic invasive macroalgal genus Caulerpa and Halimeda opuntia in coral reefs of Gulf of Mannar

nvestigations on indigenous and non-indigenous invasive flora and fauna of a certain geographical area are always important to assess their impact on native biodiversity and control their spread by making conservation strategies to protect biodiversity. In this study, we have encountered overwhelming growth of six seaweed species, Caulerpa racemosa, C. serrulata, C. sertularioides, C. taxifolia, C. peltata, and Halimeda opuntia on the reef flat. These algal covers on reef area appear to compete with coral polyps and restrict their settlement and resilience. Our concern on invasive species distribution in Gulf of Mannar revealed these overgrowing invasive species, which can become potential threats to coral reefs, benthic diversity, and reef assemblage. These observations will help us to develop multidisciplinary management approaches related to the expansion, mitigation, and control of these opportunistic invasive species. Further seasonal monitoring on these algal species is under process to investigate their spatial shift patterns on various coral forms.

An Efficient and Quick Analytical Method for the Quantification of an Algal Alkaloid Caulerpin Showed In-Vitro Anticancer Activity against Colorectal Cancer.

Biological invasion is the successful spread and establishment of a species in a novel environment that adversely affects the biodiversity, ecology, and economy. Both invasive and non-invasive species of the Caulerpa genus secrete more than thirty different secondary metabolites. Caulerpin is one of the most common secondary metabolites in genus Caulerpa. In this study, caulerpin found in invasive Caulerpa cylindracea and non-invasive Caulerpa lentillifera extracts were analyzed, quantified, and compared using high-performance thin layer chromatography (HPTLC) for the first time. The anticancer activities of caulerpin against HCT-116 and HT-29 colorectal cancer (CRC) cell lines were also tested. Caulerpin levels were found higher in the invasive form (108.83 ± 5.07 µg mL-1 and 96.49 ± 4.54 µg mL-1). Furthermore, caulerpin isolated from invasive Caulerpa decreased cell viability in a concentration-dependent manner (IC50 values were found between 119 and 179 µM), inhibited invasion-migration, and induced apoptosis in CRC cells. In comparison, no cytotoxic effects on the normal cell lines (HDF and NIH-3T3) were observed. In conclusion, HPTLC is a quick and novel method to investigate the caulerpin levels found in Caulerpa extracts, and this paper proposes an alternative utilization method for invasive C. cylindracea due to significant caulerpin content compared to non-invasive C. lentillifera.

Caulerpa chemnitzia in Darwin threatening Galapagos coral reefs.

Coral reefs are rare in the Galapagos and there is concern that, like in many areas around the world, they may be degrading due to increasing anthropogenic pressure, which can cause changes and reorganizations of structure and function with associated phase shifts. Algae of the genus Caulerpa J.V. Lamouroux, 1809 are known as widespread and persistent marine invaders. They grow rapidly, particularly in disturbed areas where they can opportunistically monopolize substratum and compete with native species, thus reducing biodiversity. Caulerpa chemnitzia increased in abundance and overgrew corals on the reef since 2012, ultimately raising fears that a phase-shift from coral to algae might be imminent. However, from 2019 onwards algae populations strongly contracted and while not having returned to baseline level, there is currently low risk of corals being displaced. Visual censuses were conducted on a yearly basis since 2004 using sample quadrats (0.5 x 0.5m) every 5 m along a 50-m-long transects at a depth of 6–15 m at 5 permanent subtidal ecological monitoring sites around Darwin. In addition, 10 m photo-transects were taken using a graduated meter-long measuring stick in the centre of the frame in 2012, 2014, 2016, 2017, 2018 and 2021 at a depth of 15m at Wellington reef. The authors hypothesize that this species could have expanded its distribution over Wellington Reef because of its known morphological plasticity due to a response to change in the environment, in this case high temperature and low nutrients. As ENSO events are predicted to increase in intensity and frequency due to the impact of climate change it is important to develop and implement a functional alert system. Early Detection Rapid Response (EDRR) protocols are recommended to avoid climate driven Non-Indigenous Species (NIS) entering the GMR or for native species becoming invasive due to warming-related phase shifts.

Ecological speciation by sympatric host shifts in a clade of herbivorous sea slugs, with introgression and localized mitochondrial capture between species

Host shifting in insect-plant systems was historically important to the development of ecological speciation theory, yet surprisingly few studies have examined whether host shifting drives diversification of marine herbivores. When small-bodied consumers feed and also mate on a preferred host, disruptive selection can split a population into host races despite gene flow. Support for host shifts is notably lacking for invertebrates associated with macroalgae, where the scale of dispersal by planktonic larvae often far exceeds the grain of host patchiness, and adults are typically less specialized than terrestrial herbivores. Here, we present a candidate example of ecological speciation in a clade of sea slugs that primarily consume green algae in the genus Caulerpa, including highly invasive species. Ancestral character state reconstructions supported ‘sea grapes’ (C. racemosa, C. lentillifera) as the ancestral host for a tropical radiation of 12 Elysia spp., with one shift onto alternative Caulerpa spp. in the Indo-Pacific. A Caribbean radiation of three species included symaptric host shifts to Rhipocephalus brevicaulis in the ancestor of E. pratensis Ortea & Espinosa, 1996, and to C. prolifera in E. hamanni Krug, Vendetti & Valdes 2016, plus a niche expansion to a range of Caulerpa spp. in E. subornata Verrill, 1901. All three species are broadly sympatric across the Caribbean but are host-partitioned at a fine grain, and distinct by morphology and at nuclear loci. However, non-recombining mtDNA revealed a history of gene flow between E. pratensis and E. subornata: COI haplotypes from E. subornata were 10.4% divergent from E. pratensis haplotypes from four sites, but closely related to all E. pratensis haplotypes sampled from six Bahamian islands, indicating historical introgression and localized “mitochondrial capture.” Disruptive selective likely fueled divergence and adaptation to distinct host environments, indicating ecological speciation may be an under-appreciated driver of diversification for marine herbivores as well as epibionts and other resource specialists.

Caulerpin Mitigates Helicobacter pylori-Induced Inflammation via Formyl Peptide Receptors

The identification of novel strategies to control Helicobacter pylori (Hp)-associated chronic inflammation is, at present, a considerable challenge. Here, we attempt to combat this issue by modulating the innate immune response, targeting formyl peptide receptors (FPRs), G-protein coupled receptors that play key roles in both the regulation and the resolution of the innate inflammatory response. Specifically, we investigated, in vitro, whether Caulerpin—a bis-indole alkaloid isolated from algae of the genus Caulerpa—could act as a molecular antagonist scaffold of FPRs. We showed that Caulerpin significantly reduces the immune response against Hp culture filtrate, by reverting the FPR2-related signaling cascade and thus counteracting the inflammatory reaction triggered by Hp peptide Hp(2–20). Our study suggests Caulerpin to be a promising therapeutic or adjuvant agent for the attenuation of inflammation triggered by Hp infection, as well as its related adverse clinical outcomes.

Green Algal Models for Multicellularity.

The repeated evolution of multicellularity across the tree of life has profoundly affected the ecology and evolution of nearly all life on Earth. Many of these origins were in different groups of photosynthetic eukaryotes, or algae. Here, we review the evolution and genetics of multicellularity in several groups of green algae, which include the closest relatives of land plants. These include millimeter-scale, motile spheroids of up to 50,000 cells in the volvocine algae; decimeter-scale seaweeds in the genus Ulva (sea lettuce); and very plantlike, meter-scale freshwater algae in the genus Chara (stoneworts). We also describe algae in the genus Caulerpa, which are giant, multinucleate, morphologically complex single cells. In each case, we review the life cycle, phylogeny, and genetics of traits relevant to the evolution of multicellularity, and genetic and genomic resources available for the group in question. Finally, we suggest routes toward developing these groups as model organisms for the evolution of multicellularity.

Comparative evaluation of multiple protein extraction procedures from three species of the genus Caulerpa

The aim of this study was to define the simplest and least expensive protocol for total protein extraction for three different macroalgae of the genus Caulerpa (the invasive C. taxifolia and C. cylindracea and the autochthonous C. prolifera). Five multi-step protein extraction procedures, set up for other macroalgal species, were tested. For each of them, different pre-treatment and extraction conditions were simultaneously examined, according to a factorial design, considering the starting material, the solvent-to-biomass ratio, and the incubation temperature. Protein yield in the obtained extracts was estimated with the Bradford method. Further, polyacrylamide gel electrophoresis (SDS-PAGE) was used to resolve proteins, assessing their quality and integrity. Significant differences in protein yield were observed among the extraction protocols and the conditions tested, also in relation to the considered species. Profiles having an acceptable quality were obtained for C. prolifera and C. cylindracea, and from the obtained results, the best method to obtain high yield and quality protein extracts for the two above-mentioned species appears to require the use of a primary TCA/acetone extraction buffer followed by a lysis buffer with NaCl, KCl, urea, Triton, SDS and a protease inhibitor. The best results, in particular, were obtained starting from fresh pulped material with a buffer-to-biomass ratio of 10:1 and an incubation temperature of 4°C. For C. taxifolia, instead, none of the tested protocols produced satisfactory results and further studies will be required.

Biodiversity consequences of Caulerpa prolifera takeover of a coastal lagoon

The genus Caulerpa has attracted much attention because many of its species were introduced into non-native regions and became notoriously invasive. This is the case of Caulerpa prolifera that has been rapidly expanding in Ria Formosa lagoon, taking over the deeper unvegetated soft bottoms and competing with seagrass meadows in the shallower areas. Here we address how C. prolifera invasion may affect the support of biodiversity, and specifically, the provision of habitat and nursery for commercial species by the native habitats of this coastal lagoon. Even though no significant differences in total species richness, diversity and evenness were found between C. prolifera and the native unvegetated habitat, the dissimilarity between these two habitats was highest, mostly driven by the extreme reduction of the gastropod Bittium reticulatum and of the tanaid Apseudopsis formosus. This may implicate changes in the trophic interactions of the ecosystem, for example decreasing the tanaid food source for seahorses, which are presently endangered in the lagoon. On the other hand, the fauna species richness, diversity and evenness were significantly higher in the native seagrass habitat than in C. prolifera. Juveniles of valuable flat and sparid fish were only observed in unvegetated sediments and seagrass meadows, respectively. The aggressive spread of C. prolifera in Ria Formosa may alter the structure of native faunal communities, with likely negative implications on fisheries. Nevertheless, the global biodiversity of the lagoon will not be likely drastically affected unless the seaweed takes over the seagrass meadows.

Stressful Conditions Give Rise to a Novel and Cryptic Filamentous Form of Caulerpa cylindracea

Morphological plasticity can enable algae to adapt to environmental change and increase their invasibility when introduced into new habitats. Nevertheless, there is still a lack of knowledge on how such plasticity can affect the invasion process of an invasive species. In this context, the high plasticity in the genus Caulerpa is well documented. However, after an extremely hot summer, a previously unreported filamentous morphology of Caulerpa cylindracea was detected; indeed, this morphology could only be confirmed taxonomically after in-depth morphological characterization and molecular analysis with the genetic marker tufA. We describe an ex situ culture experiment which showed that stressful conditions, such as high temperatures, can trigger this morphological change. Almost all of the thalli maintained at a constant extreme temperature of 29°C died, but after being returned to optimum temperature conditions, the filamentous morphology began to develop from the surviving microscopic tissue. In contrast, thalli at a control temperature of 21°C maintained the regular morphology throughout the experiment. When C. cylindracea develops this filamentous morphology, it may act as a cryptic invader because it is difficult to detect in the field. Furthermore, the filaments likely improve C. cylindracea’s invasive capabilities with regard to resistance, persistence and dispersion and may have an important role in the re-colonization process, after a population disappears following a period of stressful conditions. Possibly, C. cylindracea’s ability to respond plastically to stressful conditions might explain its remarkable success as an invasive species.

Role of Seaweed in Diets of Samoa and Kiribati: Exploring Key Motivators for Consumption

Edible seaweeds have significant potential to contribute to sustainable diets that promote health of Pacific Islanders in ecologically, economically, and socially acceptable ways. No studies to date have investigated motivators for and the consumption of edible green seaweed from the genus Caulerpa (sea grapes) in Samoa and Kiribati. An observational, cross-sectional study utilized an interviewer-administered questionnaire to explore consumption behaviors and the role of sea grapes in the current diets of individuals in Samoa and Kiribati. Of the total 145 participants (n = 79, 54.5% Samoa; n = 66, 45.5% Kiribati), half (n = 76, 52%) reported consuming sea grapes. A significantly greater proportion of Samoans (n = 56, 70.9%) reported consumption than I-Kiribati participants (n = 20, 30.3%). A greater proportion of consumers were male (n = 47, 61.8%). Samoan consumers reported consumption of sea grapes with a higher diversity of foods and being related to traditional events or ceremonies. Motivators for consumption varied between countries, with Samoan consumers reporting strong agreement for taste and value for money, and identified sea grapes as nutritious food, as influences on consumption. Easy access was a motivator in Kiribati only. The findings of this study are underpinned by the degree of food security and differences in culture in Samoa and Kiribati. Future public health efforts to integrate traditional fresh food into local food systems will need to work within the existing social parameters in each respective country.

Morphological variation of two common sea grapes (Caulerpa lentillifera and Caulerpa racemosa) from selected regions in the Philippines

Abstract. Estrada JL, Bautista NS, Dionisio-Sese ML. 2020. Morphological variation of two common sea grapes (Caulerpa lentillifera and Caulerpa racemosa) from selected regions in the Philippines. Biodiversitas 21: 1823-1832. Seagrapes, locally known in the Philippines as “lato” or “ar-arusip”, are economically important macroalgae belonging to the edible species of the genus Caulerpa. This study characterized and compared distinct populations of sea grapes from selected regions in the Philippines and described the influence of physicochemical parameters of seawater on their morphology. Morphometric, cluster and principal component analyses showed that morphological plasticity exists in sea grapes species (Caulerpa lentillifera and Caulerpa racemosa) found in different sites in the Philippines. These are evident in morphometric parameters namely, assimilator height, space between assimilators, ramulus diameter and number of rhizoids on stolon wherein significant differences were found. This evident morphological plasticity was analyzed in relation to physicochemical parameters of the seawater. Assimilator height of C. racemosa is significantly associated and highly influenced by water depth, salinity, temperature and dissolved oxygen whereas for C. lentillifera depth and salinity are the significant influencing factors. Highest assimilator height of sea grapes was found in Coron and Culion in Palawan due to higher salinity and temperature while in Mactan, Cebu, it is primarily attributed to lower depth and higher salinity values.