Liza Haematocheila Research Articles

Antioxidant Activity of Protein Hydrolysates from Redlip Mullet (Chelon haematocheilus) Muscle and Byproducts.

Fish muscle and byproducts represent a valuable source of bioactive compounds, with their protein hydrolysates exhibiting noteworthy antioxidant properties. This study assessed the antioxidant activity of protein hydrolysates derived from the muscle and byproducts of redlip mullet (Chelon haematocheilus), utilizing different proteases (Neutrase, Alcalase, and Protamex). Hydrolysates were prepared from various parts of the fish, including muscle (white and red meat) and byproducts (frames, head, viscera, fins, skin, and scales). The enzymatic hydrolysis resulted in the highest degree of hydrolysis, achieving 83.24 ± 1.45% for skin at 60 min and 82.14 ± 4.35% for head at 30 min, when treated with Neutrase. Frames treated with Neutrase exhibited the highest protein concentration, measured at 1873.01 ± 71.11 µg/mL at 15 min. Significantly, skin hydrolysates treated with Protamex showed the highest DPPH• scavenging activity (70.07 ± 3.99% at 120 min), while those treated with Alcalase demonstrated the highest ABTS• scavenging activity (93.47 ± 0.02% at 15 min). The highest superoxide dismutase (SOD) activity (92.01 ± 1.47%) was observed in head hydrolysates treated with Protamex after 90 min. These results suggest that C. haematocheilus protein hydrolysates possess significant antioxidant activity within a short time frame of less than 120 min.

A comprehensive study on the multifunctional properties of galectin-4 in red-lip mullet (Planiliza haematocheilus): Insights into molecular interactions, antimicrobial defense, and cell proliferation

Galectin-4 belongs to the galactoside-binding protein family and is a type of tandem repeat galectin. Despite previous studies indicating its importance in fish immunology, a comprehensive investigation is necessary to fully understand its role in immunomodulatory functions and cellular dynamics. Therefore, this study aimed to explore the immunomodulatory functions of galectin-4 with a particular focus on its antimicrobial and cellular proliferative properties. The open reading frame of PhGal4 spans 1092 base pairs and encodes a soluble protein of 363 amino acids with a theoretical isoelectric point (IEP) of 6.39 and a molecular weight of 39.411 kDa. Spatial expression analysis under normal physiological conditions revealed ubiquitous expression of PhGal4 across all examined tissues, with the highest level observed in intestinal tissue. Upon stimulation with poly I:C, LPS, and L. garvieae, a significant increase (p < 0.05) in PhGal4 expression was observed in both blood and spleen tissues. Subsequent subcellular localization assay demonstrated that PhGal4 was predominantly localized in the cytoplasm. The recombinant PhGal4 (rPhGal4) exhibited specific binding capabilities to pathogen-associated molecular patterns (PAMPs), including LPS and peptidoglycan, but not poly I:C. The rPhGal4 negatively affected the bacterial growth kinetics. Additionally, rPhGal4 demonstrated complete hemagglutination of fish erythrocytes, which could be inhibited by the presence of D-galactose and α-lactose. The overexpression of PhGal4 in FHM epithelial cells demonstrated a significant suppression of viral replication during VHSV infection. Furthermore, the in vitro scratch assay and WST-1 assay demonstrated a wound healing effect of PhGal4 overexpression in FHM cells, potentially achieved through the promotion of cell proliferation by activating genes involved in cell cycle regulation. In conclusion, the responsive expression to immune stimuli, antimicrobial properties, and cell proliferation promotion of PhGal4 suggest that it plays a crucial role in immunomodulation and cellular dynamics of red-lip mullet. The findings in this study shed light on the multifunctional nature of galectin-4 in teleost fish.

ЕКОСИСТЕМИ МИСІВ ПІВНІЧНО-ЗАХІДНОЇ ЧАСТИНИ ЧОРНОГО МОРЯ – ПРИРОДНІ РЕЗЕРВАТИ МОРСЬКИХ ПРИБЕРЕЖНИХ РИБ

The research paper examines the role of capes in the conservation of coastal ichthyofauna in the northwestern part of the Black Sea. The study spans from the Danube Delta to Cape Tarkhankut (Crimea). Particular attention was paid to the capes located near the megacity of Odessa – Velikyi and Malyi Fontan, Lanzheron and Odessa Pivnichnyi capes. The research incorporates archived data from the Institute of Marine Biology of the National Academy of Sciences of Ukraine, alongside literature sources and original field research conducted from May to October over the period 1981–2021. Using a landscape-biotope approach, largely similar coastal ecosystems can be identified and grouped as follows: 1 – capes, 2 – sandy bays, 3 – sandy spits of estuaries, 4 – estuaries and lagoons, 5 – river mouths. Cape ecosystems stand out due to the accumulation of large fragments of stones that extend from the shore to depths of 8–10 meters, rising above the bottom and surrounded by soft sediments. The hard substates of the capes provide settlements for macrophyte algae, bivalves and multi-species biocenosis. Bottom and near bottom-pelagic fish also find favorable conditions for survival and reproduction in the cape ecosystems owing to active hydrodynamics, presence of hard substrates and food resources. In total, 120 fish species have been recorded in the capes ecosystems, of which 18 are semianadromous and river fish species, and 7 anadromous species. Eastern Atlantic-Mediterranean species and Ponto-Caspian relics composed the basis of the ichthyofauna. There are also two introduced species: the mullet Liza haematocheilus (Temminсk et Schlegel, 1845) and the common sunfish Lepomis gibbosus (Linnaeus, 1758). Among the fish recorded in the ecosystems of capes in the northwestern part of the Black Sea, 75 species are listed in various protected (red) domestic and international lists, including 48, 52, 42, and 41 species in the ecosystems of capes Burnas, Velikyi Fontan, Adzhiyask, and Tarkhankut, respectively. Owing to the abiotic conditions, the capes ecosystem of the northwestern part of the Black Sea become reserves for hydrobionts inhabiting neighboring ecosystems during storms, in cases of acute hypoxia following release of hydrogen sulfide in coastal shallow waters, and other negative phenomena. Although the capes in the southwestern part of the Black Sea form separate enclaves and occupy up to 10 % of the coastal zone areas of the seabed, they play an essential role in conservation of biota and require special protection.

Exploring the molecular characteristics, detoxification functions, and immune responses of two glutathione S-transferases in redlip mullet (Liza haematochelia)

Exploring the molecular characteristics, detoxification functions, and immune responses of two glutathione S-transferases in redlip mullet (Liza haematochelia)

Effects of Microplastics on the Activity of Digestive-, Antioxidative- and Immune-related Enzymes in Soiny Mullet (Liza haematocheila Temminck &amp; Schlegel, 1845) Larvae

Microplastics (MPs), novel pollutants in the water environment, can cause damage to fish, especially to fish larvae. However, the effects of MPs on fish in estuarine areas with high levels of MPs pollution are unknown. In this study, a 14-day exposure test was conducted to analyze the effects of MPs on soiny mullet larvae by measuring the activities of digestive enzymes, antioxidant enzymes, and immune enzymes in soiny mullet larvae after exposure to MPs of different particle sizes (0.5 μm, 0.1mg/L; 6 μm, 0.1mg/L).Results showed that MPs exposure significantly decreased the activities of pepsin (PPS), alpha-amylase (α-AMS), catalase (CAT), and superoxide dismutase (SOD), and significantly increased the activities of acid phosphatase (ACP) and alkaline phosphatase (ALP), among which the PPS, CAT, SOD, ACP, and ALP were more sensitive to exposure to small particle size MPs (0.5 μm).Overall, exposure to MPs reduced digestion, destroyed the antioxidant system, and triggered an immune response in soiny mullet larvae, especially the small particles of MPs (0.5 μm). The results provide basis for understanding the detriment of microplastic in fish.

Galectin-8-like isoform X1 mediates antibacterial, antiviral, and antioxidant responses in red-lip mullet (Planiliza haematocheilus) through positive modulation of pro-inflammatory cytokine, chemokine, and enzymatic antioxidant activity

Galectin 8 belongs to the tandem repeat subclass of the galectin superfamily. It possesses two homologous carbohydrate recognition domains linked by a short peptide and preferentially binds to β-galactoside-containing glycol-conjugates in a calcium-independent manner. This study identified Galectin-8-like isoform X1 (PhGal8X1) from red-lip mullet (Planiliza haematocheilus) and investigated its role in regulating fish immunity. The open reading frame of PhGal8X1 was 918bp, encoding a soluble protein of 305 amino acids. The protein had a theoretical isoelectric (pI) point of 7.7 and an estimated molecular weight of 34.078 kDa. PhGal8X1 was expressed in various tissues of the fish, with prominent levels in the brain, stomach, and intestine. PhGal8X1 expression was significantly (p < 0.05) induced in the blood and spleen upon challenge with different immune stimuli, including polyinosinic:polycytidylic acid, lipopolysaccharide, and Lactococcus garvieae. The recombinant PhGal8X1 protein demonstrated agglutination activity towards various bacterial pathogens at a minimum effective concentration of 50 μg/mL or 100 μg/mL. Subcellular localization observations revealed that PhGal8X1 was primarily localized in the cytoplasm. PhGal8X1 overexpression in fathead minnow cells significantly (p < 0.05) inhibited viral hemorrhagic septicemia virus (VHSV) replication. The expression levels of four proinflammatory cytokines and two chemokines were significantly (p < 0.05) upregulated in PhGal8X1 overexpressing cells in response to VHSV infection. Furthermore, overexpression of PhGal8X1 exhibited protective effects against oxidative stress induced by H2O2 through the upregulation of antioxidant enzymes. Taken together, these findings provide compelling evidence that PhGal8X1 plays a crucial role in enhancing innate immunity and promoting cell survival through effective regulation of antibacterial, antiviral, and antioxidant defense mechanisms in red-lip mullet.

СЦЕНАРНЫЙ ПРОГНОЗ РАЗВИТИЯ СЫРЬЕВОЙ БАЗЫ РЫБОЛОВСТВА И УЛОВОВ РЫБ В АЗОВСКОМ МОРЕ В УСЛОВИЯХ СОКРАЩЕНИЯ ОБЪЕМОВ ПРЕСНОВОДНОГО СТОКА И РОСТА СОЛЕНОСТИ

Background. The reduction in freshwater runoff and the increase in the Azov Sea salinity are accompanied by a drastic transformation of aquatic biocenoses, as well as restructuring of various ecological groups of the ichthyofauna. Abrupt changes in the composition and abundance of fishing targets render traditional approaches to fishing ineffective and dictate the need to develop new kinds of fishery. Relevance. Identification of possible scenarios of the fishery resource development for the next 5–10 years is necessary to ensure the fisheries sustainability in the Azov Sea Basin. The aim of this work is to analyze the dynamics of the composition of commercial fish catches in the Azov Sea in the modern period of the sea salinization and to develop possible status scenarios for the stocks and catches of fishing targets for the next 3–10 years to substantiate fisheries management and regulation. Methods. In the course of developing such scenarios, the data on the actual dynamics and trends in the fishery resource changes during the comparable periods have been used, as well as the data on the ecological valence of the representatives of various ecological groups of fish at different stages of their ontogenesis in terms of their salinity tolerance. Results. 3 main unequally probable scenarios of changes in the abundance and biomass of various ecological groups of fish — primary industrial-scale fishing targets in the Azov Sea — have been developed; the recommendations for adapting the existing fishing practices to the changes in the fishery resources have been given. Conclusion. A further decrease in the commercial importance is predicted for the freshwater fish species, freshwater-spawning anadromous and semi-anadromous fish species, as well as for gobies and Black and Caspian Sea sprat (tyulka). The role of Black Sea migrants — European anchovy, grey mullets, red mullet, Mediterranean horse mackerel, garfish — will be reduced. Marine fish species — acclimatized so-iuy mullet and Black Sea turbot (kalkan) — will become the main fishing targets.

The distribution of monogeneans of the genus Ligophorus on gills of the soiuy mullet Planiliza haematocheilus

The distribution on the host gills of three monogenean species of Ligophorus Euzet et Suriano, 1977, parasitising soiuy mullet Planiliza haematocheilus (Temminck &amp; Schlegel, 1845) in the Black and Azov seas was studied. Specimens of L. pilengas and L. llewellyni prefer to localize on the same gill sites, namely, I-III gill arches and their medial sectors. The third species, L. kaohsianghsieni , was distributed on the gills more crowdedly, with about 80% of its specimens being present on II gill arch, occurring on the medial and ventral sectors approximately equally. In general, most monogeneans were found on the largest in area and well-watered gill arches and sectors, as well as the anterior hemibranchies, however within these areas they preferred to attach to proximal half of filaments with less amount of water current. The presence of congeners on gills had no significant effect on the distribution of L. pilengas and L. llewellyni . Increasing infrapopulation number resulted in a more uniform distribution of monogeneans on gills; their proportion upsurges significantly on the faster growing anterior hemibranchs as fish size increased.

Tidal Variations of Fish Larvae Measured Using a 15-Day Continuous Ichthyoplankton Survey in Subei Shoal: Management Implications for the Red-Crowned Crane (Grus japonensis) Population in Yancheng Nature Reserve.

The National Yancheng Rare Birds Nature Reserve is a vitally important staging habitat for the wild population of red-crowned cranes (Grus japonensis) in China. The population relies on local high-protein food sources, such as fish juveniles, to fuel their migratory journeys. However, little is known about the ecology of the fish larvae and juveniles that migrate to the inshore area via tidal rhythm in Subei Shoal, which is adjacent to the reserve. Therefore, we used a fixed study station (32°55'1.2″ N, 121°19'58.8″ E) to conduct a continuous 15-day ichthyoplankton survey at 2 h intervals beginning at 05:00 on 25 April and ending at 03:00 on 10 May 2019. We identified the tidal variations in the number of fish larvae and juveniles and the number at various developmental stages and assessed how they were related to environmental variables such as sea surface temperature, salinity, turbidity, and tidal height in the Dafeng Sea area of Subei Shoal. We found that the number of species and larval individuals were highest and lowest, respectively, at the highest and lowest tidal height, and they obviously increased and decreased with the rising and ebb tide, respectively. Our findings indicate that the variation in numbers of the larvae and juveniles depends on species and developmental stage. The species Acanthogobius ommaturus, Pholis fangi, Cynoglossus joyneri, Liza haematocheila, and Lateolabrax japonicus and the total number of larvae were most influenced by tidal height. These results provide a better understanding of the habitat of prey species of the red-crowned crane wild population as well as scientific data that can be applied to manage the wild population in the reserve sustainably.

Comparison of physical properties and fishing performance between biodegradable PLA and conventional PA trammel nets in grey mullet (Mugil cephalus) and red-lip mullet (Liza haematocheila) fishery

Marine plastic pollution and continuous capture of marine animals, so-called “ghost fishing”, by abandoned, lost, or otherwise discarded fishing gear (ALDFG) are global concerns. This study investigated whether biodegradable polylactic acid (PLA) monofilaments can be used to replace conventionally used non-biodegradable polyamide (PA) in trammel net fishery for limiting ALDFG associated effects. It evaluated the physical properties of PLA and PA monofilaments and compared fishing performance of PLA and PA trammel nets in a commercial mullet fishery in the Yellow Sea, China. Although PA monofilament exhibited superior physical properties, no significant differences in catch efficiency between PA and PLA trammel nets were observed. Fish of both species were mainly captured by pocketing which can further explain observed similar catch efficiency. These initial results suggest a potential for applying biodegradable materials in trammel net fisheries. Therefore, further long-term testing is encouraged to investigate whether this promising performance is persistent over long-term.

Assessing the Attractive Effects of Floating Artificial Reefs and Combination Reefs on Six Local Marine Species

Artificial reefs (ARs) have been advocated for and implemented as management tools for recreational fisheries, species conservation, and habitat replacement; however, the research that includes attracting marine species of floating ARs remains in its early stages. Here, two types of floating ARs were designed to evaluate the attractive effects using the occurrence rate and attracting index for six commercially important species (Lateolabrax maculatus, Liza haematocheila, Sebastes schlegelii, Acanthopagrus schlegelii, Litopenaeus vannamei, and Amphioctopus fangsiao) in the Bohai Bay of China; their combined ARs were meanwhile compared with two variants of artificial seagrass beds (SA and SB) and the traditional double-frame artificial reef (TD). All of the designed ARs were effective in attracting experimental species. The ARs with higher shelter areas (SB and TD) showed a better attracting effect. The efficiency of the ARs in attracting different species depended on their life histories. The bottom-mounted ARs were more efficient in attracting demersal species, while the floating ARs attracted epipelagic fish. In addition, the combined reefs had a better attractive effect than single ARs did. Overall, floating ARs and their combined ARs show the potential to deploy especially for attracting epipelagic fishes, although further study is needed.

Selenium in the liver facilitates the biodilution of mercury in the muscle of Planiliza haematocheilus in the Jiaozhou Bay, China

There are increasing evidences that the biodilution effect can significantly reduce the biomagnification of mercury (Hg) in fish. The significant antagonism of selenium (Se) -Hg may have a potential diluting effect on Hg in fish; however, there is still lack of knowledge on such effect. To reveal the Se-Hg interaction and its role in controlling the biodilution effect of Hg, we investigated levels of Hg and Se in the muscle and liver of redlip mullet from Jiaozhou Bay, China, an urbanized semi-enclosed bay highly impacted by human activities. In general, Hg levels in fish muscle were significantly negatively correlated to the levels of Se in the liver and fish size for fish with a size of < 200 mm, indicating that the antagonistic effect of Se on Hg increased with fish growth. This relationship was not significant for fish with a size of > 200 mm, possibly because the normal metabolism of Hg in muscle was hindered by homeostatic regulation or physiological activities such as gonadal development in vivo. Furthermore, the molar ratio of Se in the liver/Hg in the muscle was significantly increasing with Se/Hg in the liver, suggesting that the liver may be the key organ involved in Se-Hg antagonism. Moreover, both ratios continued to decrease with increasing fish size, implying that the antagonistic effect weakens with fish growth. These results indicate that Hg sequestration by liver may be a key mechanism of Se-Hg antagonism in fish and function as a driver for the biodilution effect of Hg, especially at a size of < 200 mm. These findings are further supported by the established linear model of Se-Hg antagonism at different developmental stages.

The effect of acute toxicity from tributyltin on Liza haematocheila liver: Energy metabolic disturbance, oxidative stress, and apoptosis

Tributyltin (TBT), a highly toxic and persistent organic pollutant, is widely distributed in coastal waters. Liza haematocheila (L. haematocheila) is one of bony fish distributing coincident with TBT, and exposure risk of TBT to this fish is unknown. In this study, L. haematocheila was exposed to TBT of 0, 3.4, 6.8, and 17.2 μg/L for 48 h to explore hepatic response mechanism. Our results showed that Sn content in livers increased after 48 h of exposure. HSI and histological changes indicated that TBT suppressed liver development of L. haematocheila. TBT reduced ATPase activities. The increased RB in blood and the reduced TBC were measured after exposure to TBT. T-AOC and antioxidant enzymes SOD, CAT, and GPx activities were inhibited while MDA content was increased. Liver cells showed apoptosis characteristics after TBT exposure. Furthermore, transcriptome analysis of livers was performed and the results showed energy metabolism-related GO term (such as ATPase complex and ATPase dependent transmembrance transport complex), oxidative stress-related GO term (such as Celllular response to oxidative stress and Antioxidant activity), and apoptosis-related GO term (such as Regulation of cysteine-type endopeptidase activity involved in apoptosic signaling pathway). Moreover, we found six energy metabolism-related differentially expressed genes (DEGs) including three up-regulated DEGs (atnb233, cftr, and prkag2) and three down-regulated DEGs (acss1, abcd2, and smarcb1); five oxidative stress-related DEGs including one up-regulated DEG (mmp9) and four down-regulated DEG (prdx5, hsp90, hsp98, and gstf9); as well as six apoptosis-related DEGs including five up-regulated DEGs (casp8, cyc, apaf1, hccs, and dapk3) and one down-regulated DEG (bcl2l1). Our transcriptome data above further confirmed that acute stress of TBT led energy metabolic disturbance, oxidative stress, and apoptosis in L. haematocheila livers.

Selective feeding of the mullet larvae Liza haematocheila during ontogeny in Laizhou Bay, Bohai Sea, China: The importance of small copepods in mesozooplankton as prey

The mullet Liza haematocheila is widely distributed in low-salinity waters around the world and has high economic value. However, details regarding the foraging ecology of mullet larvae remain unclear. Larvae of L. haematocheila were sampled in Laizhou Bay of the Bohai Sea, China, in May 2016, and diet composition was detected using gut content analysis to compare differences in feeding parameters and diet shift in dominant prey during ontogeny. The results showed no linear relationship between gape size (GS) and standard length (SL) at larva length &amp;lt;7 mm (flexion larvae, FL), but linear increase was observed for SL &amp;gt;7 mm (post-flexion larvae, PFL). Maximum prey size (MPS) overlapped with GS during the FL stage but was never higher than GS during the PFL stage. Trends of increasing MPS and prey size range (PSR) during the PFL stage were lower than those during the FL stage, but prey number (PN) increased significantly during the PFL stage. Diet composition analyses in mullet larvae showed a total of 10 mesozooplankton species (or categories), of which 8 species were copepods (including copepods nauplii and copepodites), and showed the dominance of 4 small copepods (&amp;lt;1 mm). Analyses of the numerical proportion of dominant copepods showed that the largest prey (Paracalanus parvus) gradually increased as GS increased; conversely, the smallest prey (nauplii of Calanus sinicus) decreased. Collectively, these results suggest that PFL tends to exhibit increased PN but not prey size or size range, and diet shifts from smaller to larger prey during ontogeny in mullet larvae. All these indicate that PFL has higher prey selection ability compared with FL, specifically switching the diet to include larger small copepods during the PFL stage and increasing the prey number instead of increasing prey size. These determine the importance of small copepods in mesozooplankton as dominant prey and facilitate predictions of the impact of climate change on mesozooplankton and fish larvae.

Molecular characterization and immune response of suppressor of cytokine signaling 5b from redlip mullet (Planiliza haematocheilus): Disclosing its anti-viral potential and effect on cell proliferation

The suppressor of cytokine signaling (SOCS) proteins family comprising eight proteins (SOCS1-7 and cytokine-inducible SH2-containing (CIS)) are classical feedback inhibitors of cytokine signaling. Although the biological role of CIS and SOCS1-3 have been extensively studied, the biological functions of SOCS4-7 remain unclear. Here, we elucidated the molecular characteristics, expression profile, immune response, anti-viral potential, and effect on cell proliferation of Phsocs5b, a member of the SOCS protein family from redlip mullet (Planiliza haematocheilus); phsocs5b comprised 1695 nucleotides. It was 564 amino acids long with a molecular weight of 62.3 kDa and a theoretical isoelectric point of 8.95. Like SOCS4-7 proteins, Phsocs5b comprised an SH2 domain, SOCS box domain, and a long N-terminal. SH2 domain is highly identical to its orthologs in other vertebrates. Phsocs5b, highly expressed in the brain tissue, was localized in the cytoplasm. Temporal changes in phsocs5b expression were observed following immune stimulation with polyinosinic: polycytidylic acid, lipopolysaccharide, and Lactococcus garvieae. In FHM cells, Phsocs5b overexpression suppressed the viral hemorrhagic septicemia virus (VHSV) infection and epidermal growth factor receptor (egfr) expression but increased the mRNA levels of pi3k, akt, pro-inflammatory cytokines (il1β and il8), and anti-viral genes (isg15 and ifn). Overall, our findings suggest that Phsocs5b attenuates VHSV infection, either by hindering the cell entry via degradation of Egfr, enhancing pro-inflammatory cytokines and anti-viral factor production, or both. The results also indicated that Phsocs5b could directly activate Pi3k/Akt pathway by itself, thus enhancing the proliferation and migration of cells. Taken together, Phsocs5b may be considered a potential therapeutic target to enhance immune responses while positively regulating the proliferation and migration of cells.

Molecular characterization, immune responses, and functional aspects of atypical prototype galectin from redlip mullet (Liza haematocheila) as a pattern recognition receptor in host immune defense system

Galectins are a family of lectins that are widely distributed β-galactoside-binding proteins identified in diverse organisms. Galectin family have appeared as pattern recognition receptors (PRRs) responsible for initiating and controlling the innate immunity. The present study aimed to study the binding ability and potential role in PRRs of galectin-related protein B-like (LhGal B-like) from redlip mullet (Liza haematocheila) involved in the host immune responses. We constructed a cDNA library of redlip mullet and identified the LhGal B-like sequence. By sequence analysis and multiple sequence alignment, we revealed that LhGal B-like contains a conserved carbohydrate recognition domain (CRD) and consists of 135 amino acids with a predicted molecular weight of 16.07 kDa. In addition, pairwise comparison results showed that LhGal B-like shares higher sequence identity (82.2–95.2%) and similarity (89–95.9%) with fish species than those (34.1–37.8% and 57.2–58.1%, respectively) with other species. The phylogenetic tree showed that LhGal B-like clustered into the fish group and was evolutionally related to Mastacembelus armatus. The tissue distribution results revealed that LhGal B-like was expressed ubiquitously in all the tested tissues, where it was highly expressed in the brain, followed by gills and muscle. The immune modulated expression of LhGal B-like was observed by injecting lipopolysaccharide (LPS), polyinosinic:polycytidylic acid (poly I:C) and Lactococcus garvieae (L. garvieae). According to the results, in the gills, the mRNA expression of LhGal B-like was significantly upregulated upon LPS treatment after 48 h and upon poly I:C treatment after 48 and 72 h. In addition, the result showed significant upregulations upon LPS and poly I:C treatment after 24 h. However, significant downregulation was also shown in the earlier phase after injection of poly I:C and L. garvieae in gills. Further, the binding affinity of recombinant LhGal B-like (rLhGal B-like) was evaluated using carbohydrate, pathogen-associated molecular patterns (PAMP) and bacterial binding assays. The rLhGal B-like could bind all the examined carbohydrates but had a higher affinity to α-lactose. PAMPs and bacterial binding experiments verified a wide range of PAMP molecules and bacterial strains that rLhGal B-like could bind to. Moreover, we examined the agglutination activity of rLhGal B-like, and the result showed that it could aggregate all the gram-positive and gram-negative bacteria. Taken together, our findings reveal the functional aspects of LhGal B-like as a PRR and the potential involvement of LhGal B-like in the innate immunity of redlip mullet.

Current state of the Sea of Azov main commercial fishery resources and ways to restore them

The paper presents the result of analyses of the Azov Sea fishery resources state for the last 15 years of the last century up to the present time. The information on quantitative and qualitative composition of commercial catches is obtained from the data of fishery statistics. Changes in temperature and salinity and their anomalies relative to mean annual values are highlighted. The first four commercial species with maximum catches have been identified: anchovy, kilka, gobies and Redlip mullet. The dynamics of their ratio, at different periods of the current century, may indicate the influence of external conditions (temperature, salinity, etc.). The forecast on increase of catches of the listed species and recommendation on development of the Azov sea fishery development programme, including all directions of fishery, introduction of the newest achievements of science and technology in development of aquaculture and other branches connected with rational use of aquatic biological resources of the sea are given.

ОЦЕНКА СОСТОЯНИЯ ЗАПАСОВ МОРСКИХ ВИДОВ РЫБ ЧЕРНОГО МОРЯ (ВОДЫ РОССИИ) В 2021 Г

Based on the available biological and fisheries data, stock status review for 18 units of the fish species inhabiting the Black Sea and the both Azov and Black Seas is presented. A modified version of the traditional approach to the harvest control rules for the aquatic bioresources of the Azov and Black Sea Fishery Basin is described for the case when they are assessed by the mathematical methods to estimate the current stock biomass and fishing mortality. For 11 stock units, analytical modeling including cohort, production and trend models has been applied. Based on the estimates of biomass and fishing mortality concerning biological reference points, in 2021, the status of six stock units of the marine fish species inhabiting the basin and exploited by the Russian fisheries was identified as increasing or stable (“Black Sea” stock units of the European sprat and European anchovy, “Crimean” stock unit of turbot, “Crimean and Caucasian” stock unit of red mullet, and “Black and Azov Seas” stock units of garfish and rays). Five fishery stock units (“Crimean and Caucasian” of mullets, picarel and Mediterranean horse mackerel, “Black and Azov Seas” of sand smelts, and “Caucasian” of turbot) have shown a decreasing trend in terms of abundance, and for the rest of the investigated fish stock units (“Mediterranean migrant” bluefish, Atlantic bonito and Atlantic mackerel, “Black Sea” whiting, so-iuy mullet and the other marine fish species, “Black and Azov Seas” spiny dogfish), the status has not been determined due to the absence of systematic biological and fishery data.

Galectin-1 from redlip mullet Liza haematocheilia: identification, immune responses, and functional characterization as pattern recognition receptors (PRRs) in host immune defense system

Galectins, a family of β-galactoside-binding lectins, have emerged as soluble mediators in infected cells and pattern recognition receptors (PRRs) responsible for evoking and regulating innate immunity. The present study aimed to evaluate the role of galectin-1 in the host immune response of redlip mullet (Liza haematocheilia). We established a cDNA database for redlip mullet, and the cDNA sequence of galectin-1 (LhGal-1) was characterized. In silico analysis was performed, and the spatial and temporal expression patterns in gills and blood in response to lipopolysaccharide polyinosinic:polycytidylic acid, and Lactococcus garvieae were estimated via quantitative real-time PCR. Functional assays were conducted using recombinant protein to investigate carbohydrate binding, bacterial binding, and bacterial agglutination activity. LhGal-1 was composed of 135 amino acids. Conserved motifs (H-NPR, -N- and -W-E-R) within the carbohydrate recognition domain were found in LhGal-1. The tissue distribution revealed that the healthy stomach expressed high levels of LhGal-1. The temporal monitoring of LhGal-1 mRNA expression in the gill and blood showed its significant upregulation in response to immune challenges with different stimulants. rLhGal-1 exhibited binding activity in response to carbohydrates and bacteria. Moreover, the agglutination of rLhGal-1 against Escherichia coli was observed. Collectively, our findings suggest that LhGal-1 may function as a PRR in redlip mullet. Furthermore, LhGal-1 can be considered a significant gene to play a protective role in redlip mullet immune system.

Molecular insights into two ferritin subunits from red-lip mullet (Liza haematocheila): Detectable antibacterial activity with its expressional response against immune stimulants

Iron (Fe) is considered as an essential micronutrient due to its diverse functions in living systems. However, regulation of free iron levels is essential because free Fe ions, in excess, induce biological toxicity through different routes, including production of reactive oxygen species. Ferritin proteins play a vital role in controlling free Fe ion homeostasis by sequestering excess iron in the body. Ferritins comprise an H subunit with a ferroxidase center and an L subunit with a Fe nucleation site. However, lower vertebrates such as fish harbor an additional subunit termed ferritin M, which shows the characteristic features of both H and L. In this study, two ferritin subunits (H and M) with ferroxidase centers were identified and characterized from red-lip mullet (Liza haematocheila). The open reading frames of red-lip mullet ferritin H (LhFerH) and ferritin M−like (LhFerM) subunits comprise 534 and 531 bps, which encode for putative polypeptides of 177 and 176 amino acids, respectively. LhFerH and LhFerM were found to retain well-conserved residues, including seven ferroxidase di-iron centers, characteristic domains, and signatures of their known homologs. We cloned the open reading frames of the two ferritin subunits to overexpress the corresponding proteins in Escherichia coli and subsequently demonstrated their iron sequestration activity along with antibacterial activity against E. coli using respective purified recombinant proteins in vitro. A basal expression analysis of two LhFer genes in selected tissues using qPCR assays showed pronounced expression in blood cells with respect to both genes. A relatively high expression level of LhFerH was also detected in muscle tissues. The expression level of LhFer in the head kidney was significantly up-regulated following lipopolysaccharides (LPS) and Lactococcus garvieae injection. The resulting gene expression pattern upon immune stimulation suggests that ferritin may contribute to the defense against harmful pathogen infection. Collectively, our results indicate that both LhFerH and LhFerM potentially participate in the homeostasis of free Fe ions and in the host immune defense of red-lip mullet.