Fish Mucus Research Articles

Mucus from different fish species alleviates carrageenan-induced inflammatory paw edema in rats

Objective: To determine the anti-inflammatory effects of mucus obtained from different fish species on the carrageenan-induced acute paw edema in rats. Methods: Forty-two rats were randomly divided into seven groups. Acute paw edema was induced by 0.1 mL of 1% carrageenan, and a single dose of diclofenac and lyophilized mucus (25 mg/kg) of rainbow trout, brook trout, European sea bass, and gilthead sea bream were administered to rats through gastric gavage 1 h before carrageenan treatment. Rat paws were measured before and 1-4 h after carrageenan treatment. The mRNA expressions of cytokines (TNF-α, IL-1β, IL-6, IL-10, and TGF-β), antioxidant markers (catalase and superoxide dismutase), and COX-2 were investigated using quantitative polymerase chain reaction. The histopathological changes were evaluated by hematoxylin and eosin staining. Results: The inhibition percentage of carrageenan-induced paw edema by different fish mucus ranged from 52.46% to 74.86% at 4 h. Histopathological evaluation showed that all fish mucus diminished carrageenan-induced edema and inflammatory cell infiltration. The upregulation of IL-1β mRNA induced by carrageenan was decreased by the mucus of rainbow trout and gilthead sea bream while an increase in the expression of IL-6 mRNA was reduced by the mucus of rainbow trout, brook trout, and gilthead sea bream. In addition, the mRNA expression of superoxide dismutase was higher in the rainbow trout mucus group than the carrageenan group. Conclusions: Mucus obtained from different fish species may have anti-inflammatory effects.

Evaluation of Antioxidant Activity and Amino Acids in the Mucus of Mackerel for Cosmetic Applications.

To identify antioxidants for improving rough skin, we aimed to analyze the amino acid composition of fish mucus and antioxidant activity of the mucus component. Specifically, we aimed to examine the antioxidant properties of dialyzed mucus components secreted from mackerel, which can be used as raw materials for producing cosmetics. The amino acid composition of hydrolyzed mucus was examined by ultra-high-performance liquid chromatography after dialyzing mucus. In addition, the antioxidant activity of the mucus was evaluated via oxygen radical absorption capacity and Trolox equivalent antioxidant capacity assays. The amino acid composition differed between the low-molecular-weight and high-molecular-weight fractions. Moreover, the low-molecular-weight fraction of farmed mackerel mucus exhibited antioxidant activity with high specificity. The results suggest that antioxidant peptides or free amino acids are present in the low-molecular-weight fraction of farmed mackerel mucus.

Preparation and drag reduction performance of biomimetic coatings derived from gelatin-3,4-dihydroxyhydrocinnamic acid gels

The purpose of this study was to develop a biomimetic coating with good drag reduction characteristics. The inspiration for the concept can be attributed to the lubricating properties of fish mucus and the water-resistant bonding ability of mussels. In this study, gelatin-3,4-Dihydroxyhydrocinnamic acid (gelatin-DOPA) was synthesized by grafting catechol groups to gelatin using EDC/NHS chemistry. Gelatin-DOPA gels were then prepared by crosslinking gelatin-DOPA with Fe3+ ions and GTA. The concentration of catechol groups in the gelatin-DOPA was found to be 0.114 mmol/g using a UV spectrophotometer. The adhesion strength was measured by lap shear tests using a mechanical tester. The drag reduction rate was determined using a rheometer. The adhesive property of the gelatin-DOPA gels to a metal substrate increased to 5.35 MPa and a drag reduction performance of the biomimetic coating derived from gelatin-DOPA gels of 40 % was achieved. The results indicate that the biomimetic coating could be applied to underwater equipment, which has potential applications in marine fields.

AMOUNT AND TYPE OF MICROBES ON THE COMMON CARP (Cyprinus carpio) IN JATILUHUR RESERVOIR WEST JAVA

This research was conducted in Microbiology Laboratory of Biology Department, Faculty of Mathematics and Natural Sciences, Padjadjaran University in May 2017. The purpose of the research was to identify the number and types of microbes contained in carp (Cyprinus carpio) in Jatiluhur Reservoir, West Java. The method used in this research was sample survey method or field survey. The water and common carp sampling stations are divided into 3 stations, station 1 is located in Zone 1 (low density), station 2 is located in Zone 3 (medium density), and station 3 is located in Zone 5 (high density). Determination of sampling location water and fish is done based on Data Recapitulation of Density of Karamba Floating Net from the Department of Animal Husbandry and Fisheries of West Java.Water samples and fish mucus were tested using Total Plate Count (TPC) method using different specific media that is Trypticase Soy Agar (TSA), deMann Ragosa Sharpe Agar (MRSA), Kliger Iron Agaar (KIA), Thiosulphate Citrate Bile salts Sucrose Agar (TCBS), and Xylose Lysine Deoxycholate (XLD). Microbes can be known by species because they just grown on specific media that can directly showed the specific characteristics of certain microbial species based on the color of the colony. The parameter observed were microbiological test (TPC). The result of the research showed that there was Bacillus sp, Escherichia coli, Lactobacillus sp, Vibrio cholerae, Vibrio parahemoliticus, Vibrio spp, dan Shigella sp on the water samples and carp mucus. The result of research on water samples and fishery products in Jatiluhur Reservoir showed that water quality in Zone 1, Zone 3, and Zone 5 is still below the threshold of microbial contamination based on SNI 7388: 2009, while fish located in Zone 3 and Zone 5 is contaminated by Escherecia coli and Vibrio cholerae, exceed the threshold of SNI 7388: 2009 on microbial contamination in fresh fish.

Hydrodynamic effects of mucus on swimming performance of an undulatory foil by using the DSD/SST method

This paper presents a DSD/SST study of the hydrodynamic effects of mucus on swimming performance of an undulatory foil in a non-Newtonian uniform flow. As the non-Newtonian effects are dominant in the boundary layer, this model can be taken as a simple strategy to study the hydrodynamic effects of fish mucus. Based on the simulations by varying the power-law fluid behavior index, some propulsive properties including the drag coefficients, the power coefficients, and the flow fields are analyzed in detail. It is found that in addition to other biological functions, the fish mucus serves to reduce the friction, enhance the thrust, save hydrodynamic power, reduce the force oscillations, and reduce the swimming sound. This work provides a better understanding of the fish mucus effects from the point of view of hydrodynamics.

Efficacy of bath vaccination with a live attenuated Vibrio harveyi against vibriosis in Asian seabass fingerling, Lates calcarifer

Vibrio harveyi causes vibriosis in various marine aquaculture fish species, especially when they are young. The infection subsequently leads to significant economic losses for aquaculture farms. Vaccination is recommended to control this disease. This study describes the efficacy of a live attenuated V. harveyi strain MVh_vhs (LAVh) as a vaccine candidate in controlling infection by wild‐type V. harveyi (WTVh) in Lates calcarifer. A total of 240 fingerlings were divided into four groups. Group 1 was not vaccinated and was not challenged, Group 2 was vaccinated with a formalin‐killed V. harveyi (FKVh), Group 3 was vaccinated with the LAVh before challenge and Group 4 was not vaccinated and was challenged. Bath vaccination was employed for one hour before the LAVh distribution was determined in the fish mucus, gill, liver, gut, kidney and spleen. The gills, livers, kidneys and skins were also sampled for gene expression analysis. To challenge the fish, skin abrasion was conducted before the fish were challenged by immersion with WTVh. The results revealed an extensive distribution of the LAVh in the liver and kidneys of the fish in Group 3 for the first 12 hr, resulting in mild lesions compared with Group 1. Similarly, there were significantly (p < .05) higher expressions of the Chemokine ligand 4 and major histocompatibility complex I genes in the skin and liver of the fish in Group 3 in comparison with other groups. Vaccination with LAVh resulted in a significantly high rate of survival (68%) of the fingerlings after being challenged with WTVh.

Mayflies avoid sweets: fish skin mucus amino sugars stimulate predator avoidance behaviour of Baetis larvae

Nonconsumptive effects of predators can have knock-on effects on prey fitness, life history and population dynamics. However, the origin of cues stimulating predator avoidance behaviour and the mechanisms underlying prey responses need further investigation. Previous studies revealed that nonconsumptive effects of predatory fish on Baetis mayfly larvae are mediated by water-borne chemical cues released from fish mucus. However, there are conflicting results regarding the nature of these cues and the specific role of the activity of fish mucus-dwelling bacteria in stimulating predator avoidance by prey. To address those conflicting results, we investigated whether bacteria dwelling in fish mucus and/or chemical components present in fish mucus are responsible for the predator avoidance response by Baetis mayflies to salmonids. Results of five bioassays conducted in microcosms revealed that to stimulate Baetis predator avoidance behaviour: (1) bacteria do not need to be present in salmonid mucus; (2) the saccharide fraction of the fish mucus glycosaminoglycan component, but neither the protein fraction nor the whole molecule, functions as a kairomone; (3) specific active components of the saccharide fraction are primarily amino sugars in the form of hexosamines; and (4) there is a minimum dose of mucus and specifically of hexosamine needed. Our study provides the first experimental evidence that mayfly larvae recognize fish predators via the amino sugars naturally present in fish skin mucus. These sugars are released into the water by microbially mediated breakdown of glycosaminoglycans. Further research on the responses of different invertebrate prey species to similar predator cues are needed to understand the evolutionary history of this kairomone recognition behaviour.

Inclusion of yeast and/or fructooligosaccharides in diets with plant‐origin protein concentrates for rainbow trout (Oncorhynchus mykiss) fingerlings

AbstractPrebiotics and probiotics improve growth and immune responses in fish. However, their inclusion affects fish when combined with plant proteins is not well studied. The effects of diets with plant concentrates supplemented with yeast Saccharomyces sp. (Y) and/or fructooligosaccharides (FOS) on growth and nonspecific immune responses were determined in rainbow trout. A basal diet (soy, rice protein concentrates, and corn gluten—200, 200, and150 g/kg, respectively) was supplemented with Y (15 g/kg), FOS (5 g/kg), or Y + FOS (15 and 5 g/kg). The basal diet corresponded to the control. Triplicate tanks with 20 fingerlings (initial weight of 1.3 ± 0.1 g; mean ± SE) were fed for 70 days. Higher values of weight gain and specific growth rate were observed in fingerlings fed with Diet Y; the lowest values were observed in the control group. Leucocytes were higher in fish fed with the FOS diet, whereas the burst activity of macrophages was higher in Y‐fed fish. Lysozyme activity in the serum did not show differences among the experimental groups, but significantly higher values were observed in the skin mucus of fish fed Diet Y. The present research shows that the inclusion of yeast with plant protein concentrates improved the growth and burst activity of macrophages in the fingerlings.

Fugu, Takifugu ruberipes, mucus keratins act as defense molecules against fungi

Keratin is a cytoskeletal protein that constitutes the intermediate filament. Its distribution is restricted to epithelial tissues in mammals, but is wider in fish. An interesting feature of fish keratin is that it is abundant in the cutaneous mucus. However, the biological function of keratin in the mucus has not been explored. In the present study, we hypothesized that mucus keratins of fugu Takifugu rubripes function as antimicrobial molecules. To verify this hypothesis, we first identified all of the keratins expressed in the epidermis and present in mucus. Five of 15 keratins including Tr-K4 expressed in the epidermis were identified in the mucus. Subsequently, we examined the interaction of keratin molecules present in fugu mucus with yeast. Affinity chromatography using yeast as a carrier and subsequent LC–MS/MS analysis revealed that three types of keratin were bound to the yeast. Furthermore, yeast incubated with fugu mucus was agglutinated, and this was inhibited by anti-recombinant Tr-K4 (rTr-K4) antibody. Immunohistochemical analysis also revealed that keratin was attached to the surface of agglutinated yeasts. These findings indicate that mucus keratin agglutinates yeast. Furthermore, we found insoluble clumps in fugu mucus, which were mainly comprised of keratin. After incubation of yeast with soluble mucus fraction, insoluble clumps incorporating yeast were formed. This observation suggests that fugu mucus keratin sequesters microbes into insoluble clumps, which are eventually eliminated from the mucus. Here, we present our finding of the novel function of keratin as a defense molecule in fish mucus.

Seasonal changes of hydrolytic enzyme activities in the skin mucus of rainbow trout, Oncorhynchus mykiss at different body sizes

The innate immune factors in the skin mucus of fish are affected by the ecological and physiological conditions such as developmental stage and seasonal cycle. The aim of this study was to investigate the seasonal changes in soluble protein and the hydrolytic enzyme activities of the skin mucus of rainbow trout including lysozyme, alkaline phosphatase (ALP) and proteases at different body sizes. Skin mucus samples were collected over three consecutive season periods including winter, spring and late summer. In each season, sampling was performed separately from three different weight groups including 2–20 g (W1), 100–200 g (W2) and 400–600 g (W3) fish. Our results showed a significant increase of soluble protein in all three weight groups from winter to spring when water temperature elevated from 9 °C to 14 °C. Moreover lysozyme activity was remarkably elevated in W1 fish from winter to late summer. In all three seasons, the activity of lysozyme was significantly decreased along with increasing the fish size. Contrary to lysozyme, the activity of proteases and ALP showed a decreasing trend from winter to late summer. A significant positive correlation was found between the proteases and ALP activity, proposing that both proteases and ALP might have important synergic roles in the mucosal innate immune function of rainbow trout. Moreover, using reverse transcription PCR (RT-PCR) analysis of some proteases genes including cathepsin-L and cathepsin-D, we demonstrated that the proteases are transcribed and likely synthesized in epidermal mucus cells of rainbow trout. The present study confirmed seasonal changes of hydrolytic enzyme activities in the skin mucus of rainbow trout across all three weight groups, with the highest variation in juvenile fish.

Effects of dietary heat-killed Pseudomonas aeruginosa strain VSG2 on immune functions, antioxidant efficacy, and disease resistance in Cyprinus carpio

A probiotic strain of Pseudomonas aeruginosa VSG2 was previously isolated from the gut of Indian major carp Labeo rohita. But, its efficacy as a heat-inactivated probiotic on the immune response of fish remains unexplored. Thus, present study investigated the effect of heat-killed P. aeruginosa VSG2 (HK-PA) supplementation on the immune function, digestive enzymatic activities, and antioxidant status of Cyprinus carpio. Moreover, the effect of HK-PA supplementation on the susceptibility of C. carpio to Aeromonas hydrophila challenge was also evaluated. To do so, diets containing five different concentrations of HK-PA (mg kg−1) (0 [basal diet], 10 [PA10], 20 [PA20], 30 [PA30], and 40 mg kg−1 [PA40]) were fed to fish for 8 weeks. The results revealed that immune-related factors, such as lysozyme, protein level, alkaline phosphatase, and alternative complement pathway levels increased in fish fed with HK-PA, but differences were significant in PA20–PA40 compared to the control. The immunoglobulin level was higher (p < .05) in PA30, compared to the control. Superoxide dismutase (SOD), glutathione, glutathione peroxidase (GPx), and myeloperoxidase levels significantly increased in serum or skin mucus of fish fed with HK-PA. Accordingly, malondialdehyde levels decreased in fish fed with HK-PA. Among intestinal enzymatic activities, protease activity was higher in the HK-PA fed groups compared to the control. Moreover, mRNA expression of antioxidant genes (SOD, GPx, and catalase) significantly increased in the liver of PA20–PA40. Fish in the PA30 exhibited the highest relative post-challenge survival (71.54 ± 5.37%) against A. hydrophila infection. Overall, dietary administration of HK-PA at 30 mg kg−1 (PA30) for 8 weeks improved (p < .05) the skin mucosal and serum immune parameters, strengthened antioxidant capacity, enhanced intestinal enzymatic activities, and increased the resistance against a pathogen challenge. The heat-killed P. aeruginosa VSG2 represents a promising dietary supplement for carps in aquaculture.

F2-isoprostanes in Fish mucus: A new, non-invasive method for analyzing a biomarker of oxidative stress

F2-isoprostanes (F2-isoPs) are a reliable biomarker class for oxidative stress in vivo in animals. These compounds are traditionally measured in matrices like liver and plasma, however social and environmental pressures warrant the development of non-lethal and non-invasive methods to assess animal health. Therefore, this study aimed to develop a high-performance liquid chromatography tandem mass spectrometry (HPLC-ESI-MS/MS) method to separate and detect F2-isoPs in fish mucus. The method was developed and validated for four native F2-isoP isomers using Northern pike mucus (Esox lucius). Linearity was observed between 5 and 1000 pg/μL. The limits of detection of the four F2-IsoP isomers ranged from 0.63 to 2.0 ng/g. Recoveries ranged from 78 to 95%, and matrix effects were small (<10%). The between-day and within-day repeatability for all target analytes was lower than 20% RSD. Endogenous F2-isoPs were measured in the pike mucus (5.3–28.8 ng/g). A preliminary study of baseline F2-isoP concentrations in lake trout (Salvelinus namaycush) captured from five lakes at the IISD-Experimental Lakes Area in Northwestern Ontario, Canada, was also conducted to test the interspecies applicability of the method. Endogenous F2-isoPs were quantified in lake trout (6.3–132 ng/g). Lake trout samples displayed large variability within and between the different lakes, which suggests sampling methods may require adjustment for this species. This work developed a sensitive analytical method for measuring F2-isoPs in fish mucus, however several further studies are required to determine its ability to accurately measure oxidative stress in fish species.

Convergent Evolution of Mucosal Immune Responses at the Buccal Cavity of Teleost Fish.

SummaryThe buccal mucosa (BM) is a critical first line of defense in terrestrial animals. To gain further insights into the evolutionary origins and primordial roles of BM in teleosts here we show that rainbow trout, a teleost fish, contains a diffuse mucosal associated lymphoid tissue (MALT) within its buccal cavity. Upon parasite infection, a fish immunoglobulin specialized in mucosal immunity (sIgT) was induced to a high degree, and parasite-specific sIgT responses were mainly detected in the buccal mucus. Moreover, we show that the trout buccal microbiota is prevalently coated with sIgT. Overall our findings revealed that the MALT is present in the BM of a non-tetrapod species. As fish IgT and mucus-producing cells are evolutionarily unrelated to mammalian IgA and salivary glands, respectively, our findings indicate that mucosal immune responses in the BM of teleost fish and tetrapods evolved through a process of convergent evolution.

Biochemical and biological characterization of the Hypanus americanus mucus: A perspective on stingray immunity and toxins

Stingrays skin secretions are largely studied due to the human envenoming medical relevance of the sting puncture that evolves to inflammatory events, including necrosis. Such toxic effects can be correlated to the biochemical composition of the sting mucus, according to the literature. Fish skin plays important biological roles, such as the control of the osmotic pressure gradient, protection against mechanical forces and microorganism infections. The mucus, on the other hand, is a rich and complex fluid, acting on swimming, nutrition and the innate immune system. The elasmobranch's epidermis is a tissue composed mainly by mucus secretory cells, and marine stingrays have already been described to present secretory glands spread throughout the body. Little is known about the biochemical composition of the stingray mucus, but recent studies have corroborated the importance of mucus in the envenomation process. Aiming to assess the mucus composition, a new non-invasive mucus collection method was developed that focused on peptides and proteins, and biological assays were performed to analyze the toxic and immune activities of the Hypanus americanus mucus. Pathophysiological characterization showed the presence of peptidases on the mucus, as well as the induction of edema and leukocyte recruitment in mice. The fractionated mucus improved phagocytosis on macrophages and showed antimicrobial activity against T. rubrumç. neoformans and C. albicans in vitro. The proteomic analyses showed the presence of immune-related proteins like actin, histones, hemoglobin, and ribosomal proteins. This protein pattern is similar to those reported for other fish mucus and stingray venoms. This is the first report depicting the Hypanus stingray mucus composition, highlighting its biochemical composition and importance for the stingray immune system and the possible role on the envenomation process.

Effects of dietary dehydrated lemon peel on some biochemical markers related to general metabolism, welfare and stress in gilthead seabream (Sparus aurataL.)

Dehydrated lemon peel (DLP) at two levels (1.5% and 3%) was included for 30 days in the diet of gilthead seabream (Sparus aurata L.) and after 15 and 30 days the serum and skin mucus of fish were analysed. In serum, both experimental diets led to an initial decrease in glucose and lactate after which the levels became comparable to the control. Dietary DLP modulated the activity of transaminases, alanine aminotransferase and aspartate aminotransferase. The total antioxidant status showed a progressive increase in relation to levels of inclusion of DLP and time of administration (p < .05). In skin mucus, some biomolecular markers related to general stress, oxidative stress and apoptosis exhibited variations that suggest an adaptive response of fish to the new metabolic situation, resulting from the experimental diet. The inclusion of DLP in the diet seems to positively modulate the central metabolism and welfare of gilthead seabream.

Administration of antibiotics can cause dysbiosis in fish gut

Compositions of gastrointestinal microorganisms are known to vary depending on surrounding environment, health status and diet. However, comprehensive analysis of composition and diversity of gut microbiota of fish after treatment with antibiotics has been limited. In this study, therefore, effects of oxytetracycline (OTC) or amoxicillin (AMX) administration on intestinal microbiota of olive flounder, Paralichthys olivaceus, were investigated. Fish were administered with AMX and OTC by oral (80 mg/kg of BW/day for 10 days) or intramuscular injection (12.5 mg/kg bw and 50 mg/kg bw) route. Culture-dependent method and metagenome analysis were performed using samples of gut mucus taken from fish at day 0, 5 and/or 10. A total of 23 and 26 species were isolated from gut mucus of fish in oral and injection groups, respectively. Virbio scophthalmi, V. harveyi and Photobacterium damselae, and V. scophthalmi and Streptococcus parauberis were dominantly isolated from oral and injection treatment groups, respectively. In metagenomics analysis, operating taxonomic unit (OTU) counts obtained from AMX and OTC oral treatment group were 42 and 78, respectively, which are much lower than 178 OTUs retrieved from the control group. OTU counts obtained from fish injected with AMX at day 5 were 22, remarkably lower than those of other samples in injection treatment groups. These results indicate that administration of antibiotics to fish can have great impact on gut microbial community by reducing its diversity and number. Our data also show that AMX might cause changes in microbial community greater than OTC. In some cases, it can lead to significant increase of opportunistic pathogen(s), causing dysbiosis.

Plant extract-based diets differently modulate immune responses and resistance to bacterial infection in striped catfish (Pangasianodon hypophthalmus)

A feeding trial was performed to compare the effects of five ethanol herbal extracts (bhumi amla, Phyllanthus amarus Schum and Thonn [Pa]; guava, Psidium guajava L. [Pg]; sensitive plant, Mimosa pudica L. [Mp]; neem, Azadirachta indica A. Juss [Ai] and asthma plant, Euphorbia hirta L. [Eh]) on the immune response and disease resistance against Edwardsiella ictaluri infection of striped catfish (Pangasianodon hypophthalmus). Fish were fed diets supplemented with two doses of each plant extract (0% [basal diet], 0.4% Eh [Eh0.4], 2.0% Eh [Eh2.0], 0.2% Pa [Pa0.2], 1.0% Pa [Pa1.0], 0.2% Pg [Pg0.2], 1.0% Pg [Pg1.0], 0.4% Mp [Mp0.4], 2.0% Mp [Mp2.0], 0.4% Ai [Ai0.4], 2.0% Ai [Ai2.0]) for 8 weeks. Results showed that hematological parameters (total red blood cells, white blood cells, lymphocytes, monocytes, and neutrophils) of fish fed extract-based diets were significantly higher than in those fed the control diet (p < 0.05) after 4 and 8 weeks. Plasma lysozyme activity increased in fish whose diets contained both doses of Eh (p < 0.05) in week 4 (W4), whereas lysozyme activity increased in fish fed 0.2% Pa and Pg, and 2.0% Ai and Eh (p < 0.05) in week 8 (W8). The lysozyme levels in skin mucus did not significantly differ between treatments (p > 0.05) in W4 and after the bacterial challenge test. At the end of the feeding trial, levels of ACH50 significantly increased in most of extract groups compared to the control group (p < 0.05). Total immunoglobulin increased considerably in both the plasma and skin mucus of fish fed extract-supplemented diets after 8 weeks. In addition, dietary supplementation with Pg, Mp, Pa0.2, Eh2.0, and Ai0.4 for 8 weeks considerably reduced the cumulative mortality against E. ictaluri infection in striped catfish. The results suggest that plant extracts possibly modulate the striped catfish immune response in a time and dose dependent manner. Specifically, diets enriched with extracts of P. guajava at 0.2 and 1.0%, or M. pudica at 2.0% for 8 weeks, have great potential for improving striped catfish health by enhancing the immune system and reducing mortality against bacterial challenges.

Novel nanostructure obtained from pacamã, Lophiosilurus alexandri, skin mucus presents potential as a bioactive carrier in fish

Nanoparticles to delivery drugs and immunomodulatory substances in fish have been widely studied by several research groups. In general, these nanoparticles are polymers, ceramic, fullerenes and metal derivates which can be toxic to fish and other aquatic organisms. We reported for the first time a nanostructured system composed of proteins obtained from pacamã fish (Lophiosilurus alexandri) mucus. We identified and characterized the formation of nanoparticles with 210.8 nm and zeta potential of −13.4 (mV). These characteristics suggest a possible application of this material as a biocompatible coating. These nanoparticles are biodegradable, metabolizable and can be easily manipulated; as well as they can easily undergo surface modification to transport biomolecules, thus exhibiting greater versatility. Our study suggests that these nanoparticles from fish mucus could be used to delivery drugs and to modulate the immune system, since they demonstrated to be biocompatible coating.

ORGANOLEPTIC PROPERTIES OF KAPE-KAPE FISH (Psenes sp) USING EXTRACT OF KECOMBRANG FLOWER (Nicolaia Spesiosa, Horan) AS A NATURAL PRESERVATIVE

Freshness is one of the important factors in determining the quality of fish. Kecombrang flower extract contains active compounds of polyphenols, flavonoids, tannins and safonin as antimicrobial ingredients. Kecombrang flower extract can be used to slow down damage to fish. The study aimed to determine the effect of using kecombrang flower extract on organoleptic properties of fish (eyes, gills, mucus, meat, odor and texture). This study used a Completely Randomized Design (CRD) of one factor, namely the use of kecombrang flower extract with concentrations (0%, 2%, 4%, and 6%) and observation times of 0, 6, 12, 18 and 24 hours. All of data were analyzed using ANOVA test. At a concentration of 6% the 12th hour storage is still able to maintain the organoleptic properties of fish. Whereas at concentrations of 0%, 2% and 4% fish are no longer suitable for consumption.

Negatively Charged Carbon Nanodots with Bacteria Resistance Ability for High-Performance Antibiofilm Formation and Anticorrosion Coating Design.

Multifunctional coatings, especially those with simultaneous antibiofilm formation and anticorrosion properties are of great significance for the marine industry. Inspired by the function of fish mucus of blackhead fish, a biological epidermal secretion with negative surface potential that protects blackhead fish from colonization of microorganisms, a concept is introduced to use negatively charged carbon nanodots (CDs) as a secure and economical dual-functional additive to prepare protective coatings. The prepared CDs with strong negative surface potential initiate robust antibiofilm formation (antiadhesion and antibacteria) and anticorrosion properties (about 60 days' durability in seawater) of polymeric coatings. The incorporated CDs with negative surface potential take effect in the following ways: 1) suppressing bacterial adhesion by virtue of strong electrostatic repulsion; 2) sterilizing anchored bacteria via destroying bacterial cell walls; 3) impeding electron ejection from the metallic surface; and 4) blocking aggressive species (H2 O and O2 ) by narrowing the microchannels. This work provides a new train of thought propelling the development of potential materials for industrial and engineering applications.