Barnacle Amphibalanus Amphitrite Research Articles

Proteomic comparison of the organic matrices from parietal and base plates of the acorn barnacle Amphibalanus amphitrite.

Acorn barnacles are efficient colonizers on a wide variety of marine surfaces. As they proliferate on critical infrastructure, their settlement and growth have deleterious effects on performance. To address acorn barnacle biofouling, research has focused on the settlement and adhesion processes with the goal of informing the development of novel coatings. This effort has resulted in the discovery and characterization of several proteins found at the adhesive substrate interface, i.e. cement proteins, and a deepened understanding of the function and composition of the biomaterials within this region. While the adhesive properties at the interface are affected by the interaction between the proteins, substrate and mechanics of the calcified base plate, little attention has been given to the interaction between the proteins and the cuticular material present at the substrate interface. Here, the proteome of the organic matrix isolated from the base plate of the acorn barnacle Amphibalanus amphitrite is compared with the chitinous and proteinaceous matrix embedded within A. amphitrite parietal plates. The objective was to gain an understanding of how the basal organic matrix may be specialized for adhesion via an in-depth comparative proteome analysis. In general, the majority of proteins identified in the parietal matrix were also found in the basal organic matrix, including nearly all those grouped in classes of cement proteins, enzymes and pheromones. However, the parietal organic matrix was enriched with cuticle-associated proteins, of which ca 30% of those identified were unique to the parietal region. In contrast, ca 30-40% of the protease inhibitors, enzymes and pheromones identified in the basal organic matrix were unique to this region. Not unexpectedly, nearly 50% of the cement proteins identified in the basal region were significantly distinct from those found in the parietal region. The wider variety of identified proteins in the basal organic matrix indicates a greater diversity of biological function in the vicinity of the substrate interface where several processes related to adhesion, cuticle formation and expansion of the base synchronize to play a key role in organism survival.

Rapid discovery of a new antifoulant: From in silico studies targeting barnacle chitin synthase to efficacy against barnacle settlement

Due to the adverse environmental impacts of toxic heavy metal–based antifoulants, the screening of environmentally friendly antifoulants has become important for the development of marine antifouling technology. Compared with the traditional lengthy and costly screening method, computer-aided drug design (CADD) offers a promising and efficient solution that can accelerate the screening process of green antifoulants. In this study, we selected barnacle chitin synthase (CHS, an important enzyme for barnacle settlement and development) as the target protein for docking screening. Three CHS genes were identified in the barnacle Amphibalanus amphitrite, and their encoded proteins were found to share a conserved glycosyltransferase domain. Molecular docking of 31,561 marine natural products with AaCHSs revealed that zoanthamine alkaloids had the best binding affinity (−11.8 to −12.6 kcal/mol) to AaCHSs. Considering that the low abundance of zoanthamine alkaloids in marine organisms would limit their application as antifoulants, a marine fungal–derived natural product, mycoepoxydiene (MED), which has a similar chemical structure to zoanthamine alkaloids and the potential for large-scale production by fermentation, was selected and validated for stable binding to AaCHS2L2 using molecular docking and molecular dynamics simulations. Finally, the efficacy of MED in inhibiting cyprid settlement of A. amphitrite was confirmed by a bioassay that demonstrated an EC50 of 1.97 μg/mL, suggesting its potential as an antifoulant candidate. Our research confirmed the reliability of using AaCHSs as antifouling targets and has provided insights for the efficient discovery of green antifoulants by CADD.

Total synthesis and structure-antifouling activity relationship of scabrolide F.

An efficient synthetic strategy for scabrolide F (7), a norcembranolide diterpene that was isolated from the Taiwanese soft coral Sinularia scabra, has only recently been reported by our group. Herein, we report details of the first total synthesis of 7. The tetrahydrofuran domain of 7 was stereoselectively constructed via the 5-endo-tet cyclization of a hydroxy vinyl epoxide. The reaction of alkyl iodide 30 with dithiane 38, followed by the introduction of an alkene moiety, afforded allylation precursor 41. The coupling of alkyl iodide 42 and allylic stannane 43 was examined as a model experiment of allylation. Because the desired allylated product 44 was not obtained, an alternative synthetic route toward 7 was investigated instead. In the second synthetic approach, fragment-coupling between alkyl iodide 56 and aldehyde 58, macrolactonization, and transannular ring-closing metathesis were used as the key steps to achieve the first total synthesis of 7. We hope that this synthetic strategy provides access to the total synthesis of other macrocyclic norcembranolides. We also evaluated the antifouling activity and toxicity of 7 and its synthetic intermediates toward the cypris larvae of the barnacle Amphibalanus amphitrite. This study is the first to report the antifouling activity of norcembranolides as well as the biological activity of 7.

Snap-through Crack Propagation in Architected Bonded Interfaces Analyzed Using a Mechanoluminescent SAO/E Coating.

We investigate the mechanics of crack propagation in architected adhesive joints whose adherends are inspired to the base plate of the barnacle Amphibalanus (=Balanus) amphitrite, and feature an array of buried hollow cylindrical channels located perpendicularly to the direction of crack growth. Selective laser sintering is used to obtain the adherends that are subsequently bonded in the double cantilever beam configuration to ascertain the mechanics of crack growth. Finite element (FE) simulations are deployed to determine the strain energy release rate (ERR) and to elucidate the salient features of the fracture process. It is shown that the channels induce a modulation of the ERR and enable a crack tip shielding mechanism. Besides, FE simulations based on a cohesive zone approach indicate the occurrence of crack pinning/depinning cycles that are validated via experiments. A highlight of the present study is the use of a mechanoluminescent (ML) coating to unravel the evolution of the transient stress field in the crack tip region. The coating comprises an optical epoxy resin loaded with doped strontium aluminate phosphors (SrAl2O4/Eu2+) and converts mechanical energy into light emission with intensity proportional to the magnitude of mechanical stress. By combining the ML emission patterns with the stress distribution obtained from FEA, we unveil interesting details of snap-through cracking in architected bio-inspired adhesive joints.

Mode of action of antifouling compound albofungin in inhibiting barnacle larval settlement

Marine biofouling causes huge economic losses to the marine industry every year. Albofungin is a potential antifoulant showing strong anti-macrofouling activities against larval settlement of major fouling organisms. In the present study, directed RNA-seq and proteomic analyses were used to investigate changes in the transcriptome and proteome of a major fouling barnacle Amphibalanus amphitrite cyprids in response to albofungin treatment. Results showed that albofungin treatment remarkably upregulated the metabolism of xenobiotics by the cytochrome P450 pathway to discharge the compound and downregulated energy metabolic processes. Intriguingly, immunostaining and whole-mount insitu hybridization (WISH) revealed the spatial expression patterns of selected differentially expressed genes (glutathione S-transferase [GST], nitric oxide synthase [NOS], and calmodulin [CaM]) distributed in the thorax and antennule of A.amphitrite. Our study provides new insights into the mechanism of albofungin in interrupting the larval settlement of A.amphitrite and suggests its potential application as an antifouling agent in marine environments.

Experimental accumulation of microplastics in acorn barnacle Amphibalanus amphitrite and its use in estimating microplastic concentration in coastal waters

Microplastic (MP) pollution has been an emerging problem in the marine environment over the last few decades. Considering wide-ranging negative impacts of MPs on marine organisms, monitoring MP pollution in marine ecosystems is essential and urgent for developing effective management of the problem. An exposure experiment was conducted to assess the potential of the striped barnacle Amphibalanus amphitrite as a bioindicator of MPs. The barnacles were exposed to either polypropylene fibers or fragments for 8 days. A full factorial experiment was conducted, with the shape (fragment, fiber), exposure concentration (10, 100, and 1000 items L-1) and exposure duration (2, 4, and 8 days) as independent factors. The highest number of MPs in A. amphitrite was 21.04 ± 15.22 fragments g-1 and 17.60 ± 13.8 fibers g-1 wet weight recorded after 4 days of exposure, and the MP concentration in the barnacles was positively correlated with the exposure concentration, regardless of the form of MPs. A regression equation relating the MP concentration in the barnacles and that in the water was computed to estimate the MP concentration in the coastal waters of Hong Kong. The predicted values were close to the published data, indicating the potential of A. amphitrite as a bioindicator of MP pollution.

Anti-Barnacle Activities of Isothiocyanates Derived from β-Citronellol and Their Structure-Activity Relationships.

Antifouling agents with low toxicity are in high demand for sustaining marine industries and the environment. This study aimed to synthesize 15 isothiocyanates derived from β-citronellol and evaluate their antifouling activities and toxicities against cypris larvae of the barnacle Amphibalanus amphitrite. The synthesized isothiocyanates exhibited effective antifouling activities (EC50 =0.10-3.33 μg mL-1 ) with high therapeutic ratios (LC50 /EC50 >30). Four isothiocyanates with an amide or isocyano group showed great potential as effective antifouling agents (EC50 =0.10-0.32 μg mL-1 , LC50 /EC50 =104-833). The enantiomers of the isothiocyanates only slightly differed in their antifouling activities. These results may serve as a basis for further research and development of β-citronellol-derived isothiocyanates as effective low-toxic antifouling agents. To the best of our knowledge, this study is the first to report the antifouling activities of isothiocyanates derived from accessible natural products.

Adding the Molecular Diversity Information of the Common Fouling Barnacle Amphibalanus amphitrite (Darwin, 1854) (Crustacea: Cirripedia) from the Persian Gulf and Gulf of Oman to the Global Diversity Pattern.

The balanid barnacle, Amphibalanus amphitrite, is known as one of the most common fouling species in the world. A phylogenetic study using material from around the world recovered three distinct clades for this species. Material from the Persian Gulf (PG) and the Gulf of Oman (GO) were not included in that survey. In the present study, we aimed to assess the genetic diversity of the balanid barnacles of these two gulfs and to evaluate their phylogeography. In total, 94 COI DNA sequences were obtained from the PG and the GO material. Most of these sequences clustered into a single clade, corresponding to clade I of the previous global study. However, two sequences, one from the PG and one from the GO, fell into a separate clade corresponding to clade III of the previous study. These two gulfs share some common haplotypes, but host several unique ones that are separated from the most common haplotype mainly by a single mutation. Based on various indices, the genetic diversity of the PG material was higher than that of the GO. Low values of ΦST show a regular gene flow among the stations and the two gulfs. The Bayesian skyline plots and the mismatch distribution analyses both showed signs of a recent population expansion in the PG and the GO. We also modeled the potential distribution areas for A. amphitrite to reveal the separate suitable habitats for the clades. The current phylogeographic status and genetic diversity of A. amphitrite in the PG and GO appears to have been shaped by both historical events and recent human activities.

Fabrication of antifouling coating based on chitosan-melanin hybrid nanoparticles as sustainable and antimicrobial surface

In the current research, we have developed a very effective, completely biocompatible, cost-effective and ecofriendly method for antifouling purposes. Melanin nanoparticles and chitosan nanoparticles were isolated from sepia ink (Sepia Pharaonis) and Penaeus merguiensis and chitosan-melanin hybrid nanoparticles complex was synthesized, under reflux circumstances to enhance the anti-biofouling properties. The result of FTIR showed that a new band between chitosan and melanin nanoparticles was in the absorption range of 1633 cm−1. Moreover, TEM and FESEM analysis of chitosan-melanin hybrid nanoparticles indicated that nanoparticles are spherical. Laboratory biological assays that including antibacterial activities, antialgal activity as well as, zooplanktonic reactions in Artemia salina and barnacle Amphibalanus amphitrite to chitosan-melanin hybrid nanoparticles were evaluated. The MIC of chitosan-melanin hybrid nanoparticles was observed against E. coli (1.56 μg/mL) and S. aureus (0.871 μg/mL) and also the median inhibition concentration (IC50) value of exposed Isochrysis galbana to chitosan-melanin hybrid nanoparticles after 48 h was 0.176 mg/mL. The field immersion was evaluated in natural seawater, in different concentration (3, 2, 1 and 0.5 % wt) of chitosan-melanin hybrid nanoparticles, for 3 month. The most successful and effective results were observed for the panel with 3 wt% chitosan-melanin hybrid nanoparticles, which had lowest weight (28 g) of biofouling. According to the findings of this study, chitosan-melanin hybrid nanoparticles have ideal and good potential to antifouling properties.

Toxic effects of pristine and aged polystyrene microplastics on selective and continuous larval culture of acorn barnacle Amphibalanus amphitrite.

This study evaluates the toxicity of pristine (Unwashed) and aged, clean (Biofilm-) or fouled (Biofilm+), PS microspheres (3 µm,10 µm), using Washed particles as a reference material, on selective and continuous larval culture of Amphibalanus amphitrite. Exposure to 3 µm Unwashed and Biofilm+ particles for 24 h induced significant mortality (60 % and 57 % respectively) in stage II larvae. Stage II and VI nauplii showed greater uptake of 3 µm Biofilm- particles. Accumulative exposure to microplastics in continuous larval culture significantly affected the naupliar survival, particularly of stage III and IV. Cumulative mortality was > 70% after exposure to 3 µm Unwashed and 10 µm Biofilm+ particles. Unwashed particles with increasing concentration and aged particles with increasing size, delayed the development of nauplii to cyprids. Though,> 50% cyprids showed successful settlement however the highest concentration of 3 µm Biofilm+ microspheres inhibited the settlement and induced precocious metamorphosis in 9 % of the cyprids.

Amphiphilic marine coating systems of self-stratified PDMS-PEG surfaces with an epoxy-polyurethane matrix

Marine coatings protect submerged surfaces from the negative effects of biofouling. In this work, we demonstrate a new method to prepare self-stratified, amphiphilic glycidyl-carbamate (GC)-based (epoxy urethane-based) coatings (AmpSiGC coatings) that have fouling-release properties making them suitable for marine use. The prepared coating systems are unique and durable in character as the bulk coating takes advantage of both epoxy and urethane functionalities while the surface is comprised of both hydrophilic and hydrophobic domains, granting it an amphiphilic characteristic. The experimental approach aimed to evaluate several factors that influence coating performance, including molecular weight of poly (ethylene glycol) (PEG) and PDMS moieties, ratio of hydrophobic (PDMS) and hydrophilic (PEG) components in the system, and the effect of different curing agents. The results demonstrated that polymeric chains of 10,000 $${\overline{M} }_{n}$$ PDMS and 750 $${\overline{M} }_{n}$$ PEG at 10–15 wt.% each offer substantially improved or comparable fouling-release performance in comparison to commercial marine coatings. This paper reports on the facile synthesis and characterization of the GC resin and GC prepolymers using FTIR and epoxy titrations; surface characterization of the coatings using ATR-FTIR, XPS, and AFM; and fouling-release assessment of the surfaces using laboratory biological assays with the barnacle Amphibalanus amphitrite, the algae Ulva linza and Navicula incerta, and the bacteria Cellulophaga lytica. Several of the AmpSiGC coatings exhibited promising performance, which were better or comparable to the internal and commercial reference coatings. The performance of the systems was dependent on all of the factors considered in this study.

Why Are Barnacles Common on Intertidal Rocks but Rare in Rock Pools? Effect of Water Temperature, Salinity, and Continuous Submergence on Barnacle Survival in Indian Ocean Rock Pools

Barnacles are less common in rock pools of the rocky intertidal zone than on open rock surfaces adjacent to those pools. Rock pools on the Andaman coastlines of Thailand showed diurnal variations in water temperature, salinity, pH, and dissolved oxygen level, peaking in the afternoon. Multivariate analysis showed that water temperature and salinity (not pH and dissolved oxygen) can affect barnacle abundance in rock pools. The present study tests the hypothesis that a lack of recruitment or pool environmental conditions (continuous submergence, water temperature, and salinity extremes) affect the abundance of barnacles (Chthamalus malayensis and Amphibalanus amphitrite) in rock pools. During the recruitment season, recruits were found in a number of rock pools, but at significantly lower abundances than those in adjacent open rock surfaces. In a laboratory experiment, C. malayensis and A. amphitrite that were continuously submerged had a lower survival (80%) than the controls (simulated tide conditions; >90% survivals). Under different water temperature and salinities treatments, barnacles had low survival (<50%) in the low salinity (0‰) and high temperature treatment (40°C). The present study suggests that C. malayensis and A. amphitrite can recruit into rock pools, and the interplay of continuous submergence, high water temperature and low salinity in rock pools can bring about mortality in barnacles.

Chromosome Genome Assembly and Annotation of the Capitulum mitella With PacBio and Hi-C Sequencing Data.

A pedunculate barnacle Capitulum mitella (Linnaeus, 1758) is a dominant intertidal cirripede (Lee et al., 2000). C. mitella distribute in the mid- and high-intertidal zone of tropical and subtropical coasts and is common in the East Sea and South Sea of China. C. mitella has a great commercial value in China, the petiole muscle of which has been a source of traditional delicious seafood (Yuan et al., 2016). The local market demand led to high-intensity catching activity, and this behavior caused significant decrease in quantity and habitat destruction in recent years. Artificial aquaculture of fishery resources will help to reduce overexploitation of natural stocks and meet market needs for fishery products. In general, the barnacle life cycle consists of six nauplius instars and a nonfeeding cyprid instar. In the barnacle life history, the cyprid is a transitory phase between the pelagic and sessile lifestyle. The cyprid role is responsible for locating, exploring, and attaching to a suitable substratum; subsequently, a complex metamorphosis and permanent settlement happen (Lagersson and Hoeg, 2002). Cypris attachment and metamorphosis are also known as “cypris settlement” (Clare and Matsumura, 2000; Franco et al., 2016). The cypris settlement is a crucial event for the survival and development of both adults and subsequent generations. Within the last three decades, the basic biology of C. mitella such as reproductive characteristics, sperm ultrastructure, and larval culture conditions was investigated in our lab. C. mitella cyprids have been cultured on a relatively large scale. However, they cannot attach and metamorphose into juveniles in an artificial environment, so they would die eventually and interrupt their life history. In recent years, the cypris morphology of C. mitella has been depicted minutely using SEM (Rao and Lin, 2014). After we had successfully induced metamorphosis of the C. mitella cyprids into juveniles, we described a time line and specific morphological changes during the metamorphosis under microscopy and SEM (Lin and Rao, 2017). The impacts of external (i.e., water temperature and salinity) and internal (i.e., cyprid age) factors on the metamorphosis of C. mitella were researched (Rao and Lin, 2020). These efforts are possible for completing the life history in an artificial environment and aquaculture of C. mitella. Not only is the artificial aquaculture for C. mitella a production activity but also it helps to reduce the stress on overexploited populations. Barnacles are frequently dominant marine foulings and widely distributed around the world that play crucial roles in marine ecology (Marechal and Hellio, 2011). Recently, there are a few transcriptome researches on barnacles, such as a model animal Amphibalanus amphitrite (Chen et al., 2011; Yan et al., 2012; Chandramouli et al., 2015; Sarah et al., 2016), a giant barnacle Megabalanus volcano (Yan et al., 2017) and a stalked barnacle Neolepas marisindica (Ryu et al., 2019). These efforts showed that the transcriptome databases could greatly promote the research on molecular mechanisms of barnacle settlement. Genome sequencing has been performed for an acorn barnacle Amphibalanus amphitrite, but there is still no genome sequencing information for a stalked barnacle. Numerous reports on C. mitella were mainly related to mitochondrial DNA sequencing and quantitative proteomics analyses (Song and Yoon, 2013; Yoon et al., 2013; Yuan et al., 2016; Tian et al., 2020). So far, no genome literature on the C. mitella is available. Whereas a lack of genome information on the barnacles has obstructed further inquiry on the molecular mechanisms with development, attachment, metamorphosis, genetic evolution, and so on, so does on C. mitella. Accordingly, in this study, we aimed to sequence and assemble the genome of C. mitella. The baseline data obtained from this study will be very useful in taxonomical identification, phylogenetic analysis, larval settlement mechanisms, artificial breeding and aquaculture, and species protection for C. mitella.

Surface modifying amphiphilic additives and their effect on the fouling-release performance of siloxane-polyurethane coatings

In this work, surface-modifying amphiphilic additives (SMAAs) were synthesized via hydrosilylation using various polymethylhydrosiloxanes (PMHS) and allyl-terminated polyethylene glycol monomethyl ethers (APEG) of varying molecular weights. The additives synthesized were incorporated into a hydrophobic, self-stratifying siloxane-polyurethane (SiPU) coating system to produce an amphiphilic surface. Contact angle experiments and atomic force microscopy (AFM), in a dry and hydrated state, were performed to assess changes in surface wettability and morphology. The antifouling and fouling-release (AF/FR) performances were evaluated by performing laboratory biological assays using the marine bacterium Cellulophaga lytica, the microalga Navicula incerta, the macroalga Ulva linza, the barnacle Amphibalanus amphitrite, and the marine mussel, Geukensia demissa. Several of the formulations showed improved AF/FR performance vs the base SiPU and performed better than some of the commercial standard marine coatings. Formulations containing SMAAs with a low grafting density of relatively high molecular weight PEG chains showed the best performance overall.

Hitchhiking of encrusting organisms on floating marine debris along the west coast of Qatar, Arabian/Persian Gulf.

The floating marine debris (FMD) and the associated rafting communities are one of the major stressors to ecosystem services, global biodiversity and economy and human health. In this study, assemblages of encrusting organisms on different types of stranded FMD along the west coast of Qatar, Arabian/Persian Gulf (hereafter referred to as 'Gulf') were examined. The analysis showed 18 fouling species belonging to 5 phyla (Annelida, Anthropoda, Bryozoa, Mollusca and Porifera) on the FMD. The most abundant fouling species were the encrusting Amphibalanus amphitrite, polychaete Spirobranchus kraussii, Bryozoan species and Megabalanus coccopoma. More number of taxa were found on larger size FMD than on smaller FMD. Some of the barnacle rafting types were found to be non-indigenous species. The central and northwest parts of the Qatar had more FMD and fouled species than in other locations. Winds and the prevailing hydrodynamic conditions (waves and currents) played an important role in the transportation and distribution of FMD and associated organisms along the west coast of Qatar. The present study confirmed that huge amount of bio-fouled FMD items, causing great damage to biodiversity, drift in the surface layer of ocean and eventually strand onto the beaches. We propose a simple, but an effective management plan for FMD and associated organisms at regional scale to restore the biodiversity, sustainability and health of the marine ecosystem in the Gulf.

Adhesive Properties of Synthetic Cement-Derived Biomaterials from the Barnacle Amphibalanus amphitrite

Barnacles, a ubiquitous biofouling organism, produce a micron-thick layer of long-lasting, proteinaceous, amyloid-like adhesive. Though studied for over a century, there is still no clear understanding of sequence traits that directly relate to the adhesive properties of the bulk material. In this work, we separate effects of chemistry and structural hierarchy by using model barnacle cement peptides (BCPs) that form nanomaterials through patterned sequence motifs. To understand the role of structure, we control the solution aggregation state of BCPs to produce films for testing that have similar chemistry but varied peptide structure.

Settlement and Recruitment Potential of Four Invasive and One Indigenous Barnacles in South Korea and Their Future

Invasion by nonindigenous species is a major threat to marine ecosystems. In this study, the distribution and occupied area (as a percentage) of four invasive barnacles (Amphibalanus amphitrite, Amphibalanus eburneus, Amphibalanus improvisus, Perforatus perforatus), and one indigenous (Balanus trigonus) barnacle in 13 ports in three Korean seas (East sea, Korea Strait, and Yellow Sea) were investigated. The average ratio for all five species was 11.17% in summer and 7.59% in winter, indicating a higher occupancy in summer. B. trigonus, which is an indigenous species, was found on all ports, except for one (IC). Of the invasive species, A. amphitrite was found mainly in the Yellow Sea, A. improvisus in the Korea Strait, and A. eburneus along with P. perforatus were found in the East Sea. From nonmetric multidimensional scaling (NMDS) analysis, six parameters related to water temperature and salinity were found to be significantly correlated with the distribution and occupancy status of these five barnacles. Using the six parameters as independent variables, random forest (RF) models were developed. Based on these models, the predicted future dominant invasive species were A. improvisus and A. amphitrite in the Yellow Sea and P. perforatus in the East Sea and Korea Strait. This study suggests that long-term monitoring of invasive species is crucial, and that determining the relationship between the results of monitoring and environmental variables can be helpful in predicting the damage caused by invasive species resulting from environmental changes.

Comparative analysis of two isocyanate-free urethane-based gels for antifouling applications

Amphiphilic gels consisting of acrylamide (AAM)/2-hydroxyethyl methacrylate (HEMA), hexafluorobutyl methacrylate (HFBMA) and non-isocyanate urethane dimethacrylate (NIUDMA) of varying molecular weights were compared. A three-level Taguchi analysis was performed using the amount of AAM/HEMA, HFBMA, NIUDMA and reaction time as dependent variables to determine the optimal formulation of the gels with maximized toughness and elastic modulus. The results were compared with commercial AF/FR Intersleek® coatings (IS 700, IS 900 and IS 1100SR) for their antifouling performance against a marine microalga (Navicula incerta), a marine bacterium (Cellulophaga lytica) and adult barnacles (Amphibalanus amphitrite). The toughness, elastic modulus and strain at break of the optimized AAM gels ranged from 3 to7 MPa, 25 to 72 MPa and 80% to 170%, respectively, whereas those of the optimized HEMA gels ranged from 1 to 3 MPa, 13 to 23 MPa and 76% to 160%, respectively. The gels, particularly AHN(E9) and HHN(E12), showed reductions of attachment compared with IS700 of up to 93% and 58%, respectively.

Toxic Effects of Pristine and Aged Polystyrene Microplastics on Selective and Continuous Larval Culture of Acorn Barnacle Amphibalanus Amphitrite

Toxic Effects of Pristine and Aged Polystyrene Microplastics on Selective and Continuous Larval Culture of Acorn Barnacle Amphibalanus Amphitrite

Distribution of Select Cement Proteins in the Acorn Barnacle Amphibalanus amphitrite

Acorn barnacles are major marine fouling organisms. Their success is largely due to an ability to adhere to diverse substrates via a sub-micron thick proteinaceous adhesive layer that develops as the organism molts and expands its base. Recent work has expanded the set of proteins identified within the adhesive interface, but one outstanding question concerns their spatial distribution throughout the organism. Here, we employ immunological analysis of Amphibalanus amphitrite tissue sections and identify the presence of two cement proteins, AaCP19-1 and AaCP43-1, in areas far removed from the adhesive interface. Confocal imaging reveals specific staining along different tissue linings of the organism as well as other non-cementing regions. Additionally, we employ a modified, pressure cycling technology approach to recover protein from histological tissue sections to perform proteomics analysis. Mass spectrometry analysis of proteins recovered from transverse histological sections of the upper portion of barnacles indicates the presence of these same proteins, complementing the immunostaining observations. The proteomics analysis also revealed the presence of other proteins first identified in the adhesive layer. While some proteins are clearly enriched at the surface interface, our findings challenge the concept that cement proteins are exclusive to the substrate interface and suggest they may have an expanded physiological role beyond substrate adhesion-related processes of A. amphitrite.