Sea Hare Research Articles

Crude extract yield, total phenolics, and total flavonoids from the ink of sea hare (Dolabella auricularia)

Crude extract yield, total phenolics, and total flavonoids from the ink of sea hare (Dolabella auricularia)

Occurrence of the Spotted Sea Hare Aplysia dactylomela (Rang 1828, Aplysiidae) in the Yeşilovacık Bay, Norteastern Mediterranean Coast of Turkey

The alien opisthobranch, Aplysia dactylomela, is recorded for the first time from the Yeşilovacık Bay in 2017. One specimen of A. dactylomela was photographed at the infralittoral zone of the Bay . The length of the specimen was 35 cm. The individual was photographed while feeding on rocks covered with algae. The first record of the A. dactylomela from the Mediterranean Sea was reported from the island of Lampedusa (Central Mediterranean Sea) was reported in 2002. In the following years, A. dactylomela was reported from the North-Eastern Sicily, from the coast of Hatay (NE Mediterranean Sea of the Turkey), from the island of Crete (Aegean Sea), from the coast of Kaş (NE Mediterranean Sea of the Turkey), from the Cirkewwa (Malta), from the Akhziv submarine canyon (Israel), from the island of Paros (Aegean Sea), from the island of Susac (Crotia), from the Montenegro (SE Adriatic Sea), from the Egadi Islands marine protected area (western Sicily), from the Capo San Donato harbour (Ligurian Sea).

Use of the sea hare (Aplysia fasciata) in marine pollution biomonitoring of harbors and bays

Our study evaluated heavy metal concentrations in soft tissues of sea hare, Aplysia fasciata, from the Lower Laguna Madre, Texas. Heavy metals in tissues followed Se>As>Pb>Cd. Concentrations ranged As (BDL-28.08), Cd (BDL-5.50), Pb (BDL-12.85) and Se (4.25–93.43ppm). Median As, Cd, Pb, and Se tissue levels exceeded exposure levels. Significant relationships occurred in metal-metal (AsCd, AsPb, CdPb, CdSe, and PbSe), metal-tissue (significant Se uptake by inhalant and exhalant siphons and As in the hepatopancreas), and metal-metal within tissue (AsPb in the hepatopancreas and CdPb in the digestive cecum) analyses (p<0.05). Bioaccumulation factors (BAF) suggested the inhalant siphon, hepatopancreas, and digestive cecum function as macroconcentrators of Cd, hepatopancreas and digestive cecum as macroconcentrators of Pb, and all tissues were deconcentrators for As and Se. As a bioaccumulator of heavy metals, Aplysia was evaluated as a bioindicator of marine pollution in harbors and bays.

Bursatella leachii from Mar Menor as a Source of Bioactive Molecules: Preliminary Evaluation of the Nutritional Profile, In Vitro Biological Activities, and Fatty Acids Contents

ABSTRACTMarine invertebrates contain nutritionally important elements that make them suitable to be included in the human diet, and they are considered an outstanding source of secondary metabolites with multiple biotechnological uses. The sea hare Bursatella leachii is an invasive species in Mar Menor that can be managed through the control of its reproduction and/or by massive biomass removal. In this context, this work evaluated the possible use of biomass from B. leachii in the food and cosmetics industries. Biomass was appraised for nutritional properties, and extracts were prepared and evaluated in vitro for antioxidant and anti-inflammatory capacity, cholinesterase and tyrosinase inhibition, and for total contents in different phenolic groups. It had a moderate moisture level, low ash and fat levels, and an adequate protein amount and protein/lipid ratio. The fatty acids (FA) profile was mainly saturated, dominated by palmitic acid. The methanol extract had the highest acetylcholinesterase inhibition. The acetone extract had the strongest capacity to scavenge 1,1-diphenyl-2 picrylhydrazyl (DPPH) radical, reduce iron, inhibit tyrosinase, decrease nitric oxide production in lipopolysaccharide (LPS)-stimulated microglia cells, and the upmost levels of total phenolics, flavonoids, and tannins. Our results suggest multiple biotechnological applications for B. leachii biomass in different economic areas.

S.12.02 - Ketamine restores changes in glutamate release, dendrite morphology and BDNF trafficking in the hippocampus of rats vulnerable to chronic mild stress

A growing body of research demonstrates that focused ultrasound stimulates activity in human and other mammalian nervous systems. However, there is no consensus on which sonication parameters are optimal. Furthermore, the mechanism of action behind ultrasound neurostimulation remains poorly understood. An invertebrate model greatly reduces biological complexity, permitting a systematic evaluation of sonication parameters suitable for ultrasound neurostimulation.Here, we describe the use of focused ultrasound stimulation with an ex-vivo abdominal ganglion preparation of the California sea hare, Aplysia californica, a long-standing model system in neurobiology. We developed a system for stimulating an isolated ganglion preparation while obtaining extracellular recordings from nerves. The focused ultrasound stimulation uses one of two single-element transducers, enabling stimulation at four distinct carrier frequencies (0.515 MHz, 1.l MHz, 1.61 MHz, 3.41 MHz).Using continuous wave ultrasound, we stimulated the ganglion at all four frequencies, and we present quantitative evaluation of elicited activation at four different sonication durations and three peak pressure levels, eliciting up to a 57-fold increase in spiking frequency.We demonstrated that ultrasound-induced activation is repeatable, and the response consistency is comparable to electrical stimulation.Due to the relative ease of long-term recordings for many hours, this ex-vivo ganglion preparation is suitable for investigating sonication parameters and the effects of focused ultrasound stimulation on neurons.

Antineoplastic Agents. 605. Isoquinstatins.

In order to further explore quinoline-type structural modification of the powerful anticancer drug dolastatin 10, an Indian Ocean sea hare constituent and parent molecule of the very successful antibody drug conjugate (ADC) Adcetris, our recent quinstatin study has been extended by replacing the quinoline ring with an isoquinoline. The resulting isoquinstatins (4-6) were modified to N-terminal desmethylisoquinstatins (7-9) and, in turn, bonded to appropriate linker units to give linker-desmethylisoquinstatin conjugates 11-13 in preparation for eventual monoclonal antibody attachment. Comparison of the new isoquinstatins with their quinstatin counterparts against six human cancer cell lines indicated the isoquinstatins to have GI50 values that were comparable to or somewhat higher than those of the isomeric quinstatins. However, desmethylisoquinstatin 5 (7) was significantly more potent than its desmethylquinstatin 5 analogue. When evaluated against quinstatin 8, its isoquinstatin 8 (6) counterpart was somewhat less potent. In general, the isoquinstatins evaluated proved to be quite strong cancer cell growth inhibitors.

40 海洋動物タツナミガイから得られた新規細胞毒性物質、ドラスタチンG、H、イソドラスタチンHの構造と合成研究(口頭発表の部)

40 海洋動物タツナミガイから得られた新規細胞毒性物質、ドラスタチンG、H、イソドラスタチンHの構造と合成研究(口頭発表の部)

The complete mitogenome of sea hares, Dolabella auricularia (Mollusca: Aplysiidae)

In this study, the complete mitogenome sequence of sea hares, Dolabella auricularia (Mollusca: Aplysiidae), has been decoded for the first time by low coverage whole genome sequencing method. The overall base composition of D. auricularia mitogenome is 31.5% for A, 14.0% for C, 16.4% for G, and 38.0% for T, and has low GC content of 30.5%. The assembled mitogenome, consisting of 14,598 bp, has unique 13 protein-coding genes (PCGs), 22 transfer RNAs, and two ribosomal RNAs genes. The D. auricularia has the common mitogenome gene organization and feature of Aplysiidae. The complete mitogenome of D. auricularia provides essential and important DNA molecular data for further phylogenetic and evolutionary analysis for Aplysiidae.

UHPLC-MS/MS profiling of Aplysia depilans and assessment of its potential therapeutic use: Interference on iNOS expression in LPS-stimulated RAW 264.7 macrophages and caspase-mediated pro-apoptotic effect on SH-SY5Y cells

Aplysia sea hares are harmless to humans and good materials for producing compounds with pharmacological properties. Aplysia species have been investigated for their human nutritional value. The knowledge on the metabolic machinery from edible Aplysia depilans Gmelin is herein broadened by identifying chlorophylls, phenolic acids, terpenes, including xanthophylls, and alkaloids, some being reported for the first time both in the species and genus. The anti-inflammatory potential was assessed using RAW 264.7 macrophages challenged with lipopolysaccharide, revealing that A. depilans ethyl acetate partionated fraction interfered with cellular NO levels, mainly due to a decrease on inducible nitric oxide synthase expression. A strong capacity to inhibit phospholipase A2 and 5-lipoxygenase was also evidenced. Morphological studies with SH-SY5Y neuroblastoma cells demonstrated chromatin condensation compatible with apoptosis, confirmed by the activation of caspase 3/7. The anti-inflammatory and pro-apoptotic effects reinforce A. depilans as an interesting ingredient to be included on the formulation of smart foods and/or nutraceuticals.

Reduction of Asthmatic Parameters by Sea Hare Hydrolysates in a Mouse Model of Allergic Asthma.

Sea hare has a variety of biological activities. However, little is known regarding the anti-asthmatic effects of sea hare. This study was performed to identify the effect of sea hare hydrolysates (SHH) on an ovalbumin (OVA)-induced allergic asthma model. The experimental asthma model was sensitized and challenged with OVA. We found that a high-dose of SHH (HSHH) significantly inhibited OVA-induced airway inflammation and mucus production around the airway in lung sections, while low- and medium-dose SHH showed an insignificant effect. In addition, HSHH highly reduced OVA-induced production of interleukin-4, -5, -13, leukotriene D4, E4, and histamine in bronchoalveolar lavage fluid. HSHH decreased the histamine-induced increase in the intracellular Ca2+ level and contractions in asthmatic smooth muscle cells. Furthermore, HSHH did not affect the weights of the spleen nor thymus, whereas dexamethasone (DEX), a steroidal anti-inflammatory drug, reduced them. Taken together, these results showed that HSHH reduced asthmatic parameters in a mouse model of allergic asthma, and suggest that SHH could be used as a potential therapeutic agent for asthma.

Isolation, Amino Acid Sequences, and Plausible Functions of the Galacturonic Acid-Binding Egg Lectin of the Sea Hare Aplysia kurodai.

Egg lectins occur in a variety of animals ranging from mollusks to vertebrates. A few examples of molluscan egg lectins have been reported, including that of the sea hare Aplysia kurodai; however, their biological functions in the egg remain unclarified. We report the isolation, determination of primary structure, and possible functions of A. kurodai lectin (AKL) from the egg mass of A. kurodai. We obtained AKL as an inseparable mixture of isoproteins with a relative molecular mass of approximately 32 kDa by affinity purification. The hemagglutinating activity of AKL against rabbit erythrocytes was inhibited most potently by galacturonic acid and moderately by xylose. Nucleotide sequencing of corresponding cDNA obtained by rapid amplification of cDNA ends (RACE) allowed us to deduce complete amino acid sequences. The mature polypeptides consisted of 218- or 219-amino acids with three repeated domains. The amino acid sequence had similarities to hypothetical proteins of Aplysia spp., or domain DUF3011 of uncharacterized bacterial proteins. AKL is the first member of the DUF3011 family whose function, carbohydrate recognition, was revealed. Treatment of the egg with galacturonic acid, an AKL sugar inhibitor, resulted in deformation of the veliger larvae, suggesting that AKL is involved in organogenesis in the developmental stage of A. kurodai.

High pCO2 and elevated temperature reduce survival and alter development in early life stages of the tropical sea hare Stylocheilus striatus

Elevated temperature (ocean warming) and reduced oceanic pH (ocean acidification) are products of increased atmospheric pCO2, and have been shown in many marine taxa to alter morphology, impede development, and reduce fitness. Here, we investigated the effects of high pCO2 and elevated temperature on developmental rate, hatching success, and veliger morphology of embryos of the tropical sea hare, Stylocheilus striatus. Exposure to high pCO2 resulted in significant developmental delays, postponing hatching by nearly 24 h, whereas exposure to elevated temperature (in isolation or in combination with high pCO2) resulted in accelerated development, with larvae reaching several developmental stages approximately 48 h in advance of controls. Hatching success was reduced by ~20 and 55% under high pCO2 and warming, respectively, while simultaneous exposure to both conditions resulted in a nearly additive 70% reduction in hatching. In addition to these ontological and lethal effects, exposure of embryos to climate change stressors resulted in significant morphological effects. Larval shells were nearly 40% smaller under high pCO2 and warming in isolation and up to 53% smaller under multi-stressor conditions. In general, elevated temperature had the largest impact on development, with temperature-effects nearly 3.5-times the magnitude of high pCO2-effects. These results indicate that oceanic conditions congruent with climate change predictions for the end of the twenty-first century suppress successful development in S. striatus embryos, potentially reducing their viability as pelagic larvae.

Antineoplastic Agents. 603. Quinstatins: Exceptional Cancer Cell Growth Inhibitors.

Discovery of the exceptionally powerful anticancer drug dolastatin 10 (1), contained in the sea hare Dolabella auricularia, opened a new frontier needed for improving human cancer treatment. Subsequently, major advances have been achieved based on results of structurally modifying this unusual natural peptide while maintaining the remarkable anticancer activity necessary for preparation of successful monoclonal antibody drug conjugates (ADC). Among the first several hundred SAR products based on dolastatin 10 our group synthesized and termed auristatins was auristatin E (2a). An anticancer activity-equivalent, desmethylaurisatin E (2b), linked to a CD30 monoclonal antibody is the very successful anticancer drug Adcetris, now approved for use in 65 countries. In the present investigation, we discovered a new subset of auristatins designated quinstatins derived from dolastatin 10 by replacing the C-terminal Doe unit with a carefully designed quinoline, which led to low or subnanomolar levels of cancer cell growth inhibition required for construction of chemically unique ADC drugs. The synthesis of quinstatins 2-8 is presented along with their cancer cell line biological data.

The embryonic life history of the tropical sea hare Stylocheilus striatus (Gastropoda: Opisthobranchia) under ambient and elevated ocean temperatures.

Ocean warming represents a major threat to marine biota worldwide, and forecasting ecological ramifications is a high priority as atmospheric carbon dioxide (CO2) emissions continue to rise. Fitness of marine species relies critically on early developmental and reproductive stages, but their sensitivity to environmental stressors may be a bottleneck in future warming oceans. The present study focuses on the tropical sea hare, Stylocheilus striatus (Gastropoda: Opisthobranchia), a common species found throughout the Indo-West Pacific and Atlantic Oceans. Its ecological importance is well-established, particularly as a specialist grazer of the toxic cyanobacterium, Lyngbya majuscula. Although many aspects of its biology and ecology are well-known, description of its early developmental stages is lacking. First, a detailed account of this species’ life history is described, including reproductive behavior, egg mass characteristics and embryonic development phases. Key developmental features are then compared between embryos developed in present-day (ambient) and predicted end-of-century elevated ocean temperatures (+3 °C). Results showed developmental stages of embryos reared at ambient temperature were typical of other opisthobranch species, with hatching of planktotrophic veligers occurring 4.5 days post-oviposition. However, development times significantly decreased under elevated temperature, with key embryonic features such as the velum, statocysts, operculum, eyespots and protoconch developing approximately 24 h earlier when compared to ambient temperature. Although veligers hatched one day earlier under elevated temperature, their shell size decreased by approximately 20%. Our findings highlight how an elevated thermal environment accelerates planktotrophic development of this important benthic invertebrate, possibly at the cost of reducing fitness and increasing mortality.

Tracing metal concentrations in egg strings of sea hare, Dolabella auricularia from Pujada Bay

Tracing metal concentrations in egg strings of sea hare, Dolabella auricularia from Pujada Bay

Identification and Characterization of a 25 kDa Protein That Is Indispensable for the Efficient Saccharification of Eisenia bicyclis in the Digestive Fluid of Aplysia kurodai.

The digestive fluid of the sea hare Aplysia kurodai can liberate approximately 2.5 mg of glucose from 10 mg of dried Eisenia bicyclis powder. Although laminaran, a major storage polysaccharide in E. bicyclis, is easily digested to glucose by the synergistic action of the 110 and 210 kDa A. kurodai β-glucosidases (BGLs), glucose is not liberated from E. bicyclis by direct incubation with these BGLs. To clarify this discrepancy, we searched for an Eisenia hydrolysis enhancing protein (EHEP) in the digestive fluid of A. kurodai. A novel 25 kDa protein that enhances E. bicyclis saccharification by β-glucosidases was purified to a homogeneous state from the digestive fluid of A. kurodai, and its cDNA was cloned from total cDNAs reverse-transcribed from hepatopancreas total RNA. The E. bicyclis extract strongly inhibited BGLs, suggesting some compound within this brown alga functioned as a feeding deterrent. However, when E. bicyclis was incubated with BGLs in the presence of EHEP, glucose production was markedly increased. As E. bicyclis is rich in phlorotannin, which are only found in brown algae, our study suggested that these compounds are the main BGL inhibitors in E. bicyclis extract. EHEP protects BGLs from phlorotannin inhibition by binding to phlorotannins and forming an insoluble complex with phloroglucinol and phlorotannins. These findings indicated that EHEP plays a key role in the saccharification of brown seaweeds containing phlorotannins in the digestive fluid of A. kurodai. This is the first report of EHEP as a phlorotannin-binding protein that protects BGLs from inhibition.

Synthesis of Natural O-Linked Carba-Disaccharides, (+)- and (-)-Pericosine E, and Their Analogues as α-Glucosidase Inhibitors.

Pericosine E (6), a metabolite of Periconia byssoides OUPS-N133 was originally isolated from the sea hare Aplysia kurodai, which exists as an enantiomeric mixture in nature. The enantiospecific syntheses of both enantiomers of Periconia byssoides OUPS-N133 has been achieved, along with six stereoisomers, using a common simple synthetic strategy. For these efficient syntheses, highly regio- and steroselective processes for the preparation of bromohydrin and anti-epoxide intermediates were applied. In order to access the unique O-linked carbadisaccharide structure, coupling of chlorohydrin as a donor and anti-epoxide as an acceptor was achieved using catalytic BF3·Et2O. Most of the synthesized compounds exhibited selectively significant inhibitory activity against α-glycosidase derived from yeast. The strongest analog showed almost 50 times the activity of the positive control, deoxynojirimycin.

Revision of the southern distribution limit for the tropical marine herbivore Syphonota geographica (A. Adams &amp; Reeve, 1850) (Heterobranchia: Aplysiidae) in a global climate change hot-spot

ABSTRACT The aplysiid sea hare, Syphonota geographica has a predominantly circumtropical distribution. Over the last 15 years, it has spread throughout the eastern Mediterranean Sea where it is reg...

Unravelling Photochemical Relationships Among Natural Products from Aplysia dactylomela.

Aplydactone (1) is a brominated ladderane sesquiterpenoid that was isolated from the sea hare Aplysia dactylomela together with the chamigranes dactylone (2) and 10-epi-dactylone (3). Given the habitat of A. dactylomela, it seems likely that 1 is formed from 2 through a photochemical [2 + 2] cycloaddition. Here, we disclose a concise synthesis of 1, 2, and 3 that was guided by excited state theory and relied on several highly stereoselective transformations. Our experiments and calculations confirm the photochemical origin of 1 and explain why it is formed as the sole isomer. Irradiation of 3 with long wavelength UV light resulted in a [2 + 2] cycloaddition that proceeded with opposite regioselectivity. On the basis of this finding, it seems likely that the resulting regioisomer, termed “8-epi-isoaplydactone”, could also be found in A. dactylomela.

About the Cover

Next article FreeAbout the CoverPDFPDF PLUSFull Text Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinked InRedditEmailQR Code SectionsMoreCover“Sea hares” such as the Aplysia punctata (Cuvier, 1803) specimen from Yorkshire, England, pictured on the cover, are coastal marine gastropods that have distinctive, pointed rhinophores that resemble the ears of terrestrial hares. Its congener A. californica is a model organism for neurobiology. All marine species, Aplysia included, face challenges from climate warming and ocean acidification, the process of decreasing seawater pH caused by increased levels of dissolved atmospheric CO2. One of the most prominent potential impacts of ocean acidification is that lower seawater pH will weaken calcium carbonate shells through dissolution, or increase the energy required to build and maintain them. Ocean acidification has also been shown to cause changes in the metabolic rates of many marine species, with further implications for the energetics of building and maintaining shells.On pages 142–151 of this issue, Nicholas Carey, Sam Dupont, and Julia Sigwart, in the first study of the effects of ocean acidification in sea hares, report the effects of extreme low pH on metabolism and shell calcification in A. punctata. They determined that low pH caused metabolic depression in these species, at least in the short term. But despite the low pH conditions, there was no impact on calcification in its internal shell. In the mollusc, shell growth occurs in two stages; first, a proteinaceous matrix is laid down, and then calcification occurs within this scaffolding, as long as acid-base balance is maintained by the animal. However, there was evidence that the lower metabolic rates resulted in reduced growth of the proteinaceous matrix, which would eventually result in reduced overall shell growth.The results of this work suggest that the prominence given to impacts of ocean acidification upon calcification may be overstated; the ability of marine invertebrates to maintain the proper conditions for calcification may be more common than previously thought. Calcification can occur even under extreme low pH conditions, as long as the supporting matrix is present. Instead, future studies should consider the overall impacts of ocean acidification on the energetics of calcifying organisms; impacts to shell growth may be due to energetic constraints, rather than the common perception of an acidic ocean dissolving away the shells of marine organisms.Credits: Photo, © Ian F. Smith, http://bit.ly/aplysia; cover design: LianneDunn.com Next article DetailsFiguresReferencesCited by The Biological Bulletin Volume 231, Number 2October 2016 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.1086/690097 © 2016 by Marine Biological Laboratory. All rights reserved.PDF download Crossref reports no articles citing this article.