Protective effect of polysaccharide from the loach on the in vitro and in vivo peroxidative damage of hepatocyte

Expression profiles of cdca9 related to ovarian development in loach (Misgurnus anguillicaudatus)

The function of borealin proteins has been widely reported in the cell division of animals. Nonetheless, there is little research about their only known paralogue (cell division cycle associated 9, cdca9). In this study, cdca9 was investigated in loach (Misgurnus anguillicaudatus) for the first time. cdca9 was highly expressed in the embryo before the gastrula stage, and it was predominantly expressed in the ovary, especially in the oocytes of stage II. In conclusion, this study reveals a potential function of cdca9 in the early embryogenesis and ovarian development of fish.

First report of a disease caused by Bacillus cereus in cultured loach Paramisgurnus dabryanus

Bacillus cereus is commonly considered a bacterium pathogenic to mammals, but several studies have suggested that it also induces diseases in fish. In 2017 and 2018, 2 strains of B. cereus, NQ-2017-17 and NQ-2018-8, were isolated from diseased large-scale loach Paramisgurnus dabryanus in Tianjin, China, and were considered to be the pathogens responsible for the disease. These stains were identified as B. cereus based on the results of 16S rDNA gene sequence analysis, Vitek biochemical tests, physiological and biochemical tests, and B. cereus group species-specific PCR. Strains NQ-2017-7 and NQ-2018-8 were found to contain virulence genes (e.g. hblA, hblC, hblD, entFM, and bceT) causing pathological damage to the spleen, kidneys, liver, and gills of loach. The median lethal dose (LD50) of NQ-2017-7 and NQ-2018-8 for loach were 1.0 ×106.64 and 1.0 ×106.49 CFU ml-1, respectively. To our knowledge, this is the first report of loach disease caused by a member of the genus Bacillus.

The Programming of Antioxidant Capacity, Immunity, and Lipid Metabolism in Dojo Loach (Misgurnus anguillicaudatus) Larvae Linked to Sodium Chloride and Hydrogen Peroxide Pre-treatment During Egg Hatching

Non-nutritional stress during early life period has been reported to promote the metabolic programming in fish induced by nutritional stimulus. Sodium chloride (NaCl) and hydrogen peroxide (H₂O₂) have been widely applied during fish egg hatching, but the influences on health and metabolism of fish in their later life remain unknown. In the present study, H₂O₂ treatment at 400mg/L but not 200mg/L significantly increased the loach hatchability and decreased the egg mortality, while NaCl treatment at 1,000 and 3,000mg/L showed no significant influences on the loach hatchability nor egg mortality. Further studies indicated that 400mg/L H₂O₂ pre-treatment significantly enhanced the antioxidant capacity and the mRNA expression of genes involved in immune response of loach larvae, accompanied by the increased expression of genes involved in fish early development. However, the expression of most genes involved in lipid metabolism, including catabolism and anabolism of loach larvae, was significantly upregulated after 200mg/L H₂O₂ pre-treatment. NaCl pre-treatment also increased the expression of antioxidant enzymes; however, only the expression of C1q within the detected immune-related genes was upregulated in loach larvae. One thousand milligram per liter NaCl pre-treatment significantly increased the expression of LPL and genes involved in fish early development. Thus, our results suggested the programming roles of 400mg/L H₂O₂ pre-treatment during egg hatching in enhancing antioxidant capacity and immune response of fish larvae via promoting fish early development.

Clock Gene Expression in the Eye Exhibits Circadian Oscillation and Light Responsiveness but is Not Necessary for Nocturnal Locomotor Activity of Japanese Loach, Misgurnus anguillicaudatus

There are few model fish that are both edible and suitable for use in the laboratory. The Japanese loach (Misgurnus anguillicaudatus) is a traditional food in Japan, but is highly neglected despite its great nutritional value. To understand its circadian system and photic input pathway for synchronization of physiological activities to environmental light-dark cycles, we measured locomotor activity under light-dark and constant dark (DD) conditions. Locomotor activity was found to be higher in the nighttime than daytime, and its rhythmicity was weakened under DD conditions. The nocturnal activity of the Japanese loach is mainly controlled by environmental light, rather than the circadian clock. We explored the circadian regulation and light-responsiveness of clock gene expression in the eyes of loaches. The daily expression profiles of its mRNA revealed that most of the examined Cry and Per genes were likely regulated by internal circadian and/or environmental light signals. Among the Opsin genes transcribed in the eye, we detected the retinal photopigment porphyropsin at the protein level, which was lower than in mice. This property of loach eyes prompted us to analyze the locomotor activities of eye-enucleated fish. As a result, they still showed nocturnal circadian activity. Thus, it is likely that extraocular photoreceptive tissue(s) also contribute to the photic input pathway, although loach eyes are a circadian photosensitive tissue. This suggests that the loach mainly uses not its vision but other stimuli, such as mechanical or chemical stimuli, detected by barbels, to coordinate its nocturnal behavior.

Expression analysis of the heat shock protein genes and cellular reaction in dojo loach (Misgurnus anguillicaudatus) under the different pathogenic invasion

As molecular chaperones, heat shock proteins (HSPs) play essential roles in cells in response to stress conditions. Recent studies about immune functions of HSPs in fish have also been reported. In this study, based on the reported cDNA sequences of the four HSP genes, HSP70, HSC70, HSP90α and HSP90β, the temporal expression patterns of the four genes during embryonic development of dojo loach(Misgurnus anguillicaudatus) was assayed with qRT-PCR. All of the four genes were ubiquitously expressed in all detected embryonic developmental stages. Among of them, HSP70, HSC70 and HSP90β were highly expressed in the organ formation stage, while HSP90α was the highest expressed in myotome formation stage. Further, the immune responses of the four HSP genes were assayed when loach were infected with three different pathogens, bacterium (Flavobacterium cloumnare G4), parasite (Ichthyophthirius multifiliis) and fungus (Saprolegnia). All of the four genes were differentially expressed in four tissues such as skin, gills, spleen and kidney in response to the pathogenic invasion, but both HSP70 and HSP90α expressions were dramatically up-regulated. Further, the cellular responses of the loach skinand gill tissues were observed, in which the number of the skin goblet cells were significantly increased, and the gill lamellae became shorter and wider after infected. Thus, our work indicated that the HSPs may directly or indirectly involved in immune defense in fish, at least in the loach.

Purification and Characterization of a New Lectin from Loach Skin Mucus

Lectin from loach skin mucus plays an important role in pathogen defense. However, hardly can any paper relevant to the character of lectin from loach skin mucus be found in recent years. In this study, a kind of new lectin (LML), with a high hemagglutination activity of 166.23 × 103 HU/mg, was successfully isolated and purified from loach skin mucus. LML was a kind of glycoprotein with a molecular weight of 245 kDa. Also, the monosaccharide composition suggested that its carbohydrate chain was composed of rhamnose, arabinose, xylose, mannose, glucose, and galactose with a molar ratio of 2.02 : 11.66 : 2.06 : 1.00 : 14.09 : 6.00. Besides, LML depended on Ca2+to induce hemagglutination and was strongly inhibited by D-lactose. The lectin exhibited powerful resistance to alkali and kept about 30% hemagglutination activity at pH 14.0, whereas its capacity of acid resistance was weak. The maximum hemagglutination activity of LML maintained at a temperature range from 20°C to 50°C. Moreover, the structure of LML was preliminarily studied, indicating it contained abundant glutamic acid, histidine, and serine, and its secondary structure containedα-helix (4.97%),β-sheet (27.55%), turns structure (49.78%), and unordered structure (17.70%).

Molecular characterization and expression analysis of T cell receptor (TCR) γ and δ genes in dojo loach (Misgurnus anguillicaudatus) in response to bacterial, parasitic and fungal challenge

In mammalian, T-cell receptors (TCRs) play a key role in recognizing the presented antigen from external to protect organisms against environmental pathogens. To understand the potential roles of TCRγ and TCRδ in dojo loach (Misgurnus anguillicaudatus), Ma-TCRγ and Ma-TCRδ cDNAs were cloned and their gene expression profiles were investigated after bacterial, parasitic and fungal challenge. The open reading frame (ORF) of Ma-TCRγ and Ma-TCRδ cDNAs contained 948 and 867 bp, encoding 316 and 288 amino acid residues, respectively. Structurally, Ma-TCRγ and Ma-TCRδ were consisted of a signal peptide, a variable region, a constant region (IgC), a connecting peptide (CPS), a transmembrane region (TM) and a cytoplasmic domain (CYT), which were similar to those of other vertebrates. Multiple sequence alignment and phylogenetic analysis showed Ma-TCRγ and Ma-TCRδ were closely related to fish of Cyprinidae family. Ma-TCRγ and Ma-TCRδ were widely expressed in all tested organs/tissues, as the highest expressions of Ma-TCRγ and Ma-TCRδ were detected in kidney and gill, respectively. In addition, three infection models of dojo loach with bacteria (F. columnare G₄), parasite (Ichthyophthirius multifiliis) and fungus (Saprolegnia sp.) were constructed. The morphological changes of gills and skin after challenged with F. columnare G₄ and Ichthyophthirius multifiliis were investigated. Compared to F. columnare G₄ infection, mRNA expression of both TCRγ and TCRδ showed higher sensitivity in classical immune organs (kidney and spleen) and mucosal tissues (skin and gill) after challenge with Ichthyophthirius multifiliis and Saprolegnia sp. Our results first indicated that TCRγ and TCRδ of dojo loach might function differently in response to challenge with different pathogens.

Immunoglobulin (Ig) heavy chain gene locus and immune responses upon parasitic, bacterial and fungal infection in loach, Misgurnus anguillicaudatus

Teleost fish are the most primitive bony vertebrates that contain immunoglobulin (Ig). Although teleost Ig is known to be important during tetrapod evolution and comparative immunology, little is known about the genomic organization of the immunoglobulin heavy-chain (IgH) locus. Here, three Ig isotype classes, IgM, IgD and IgT, were firstly identified in dojo loach (Misgurnus anguillicaudatus), and the IgH locus covering τ, μ and δ genes was also illustrated. Variable (V) gene segments lie upstream of two tandem diversity (D), joining (J) and constant (C) clusters and the genomic organization of the IgH locus presented as V_n-D_n-J_n-C_τ-D_n-J_n-C_μ-C_δ, similar to some other teleost fish. However, unlike some other teleost fish, ten V_H, ten D and nine J genes were observed in this locus, which suggest teleost Igs might be conserved and diverse. Thus, it would be interesting to determine how Igs divide among themselves in immune response to different antigens. To address this hypothesis, we have developed three models by bath infection with parasitic, bacterial and fungal pathogens, respectively. We found that IgM, IgD and IgT were highly upregulated in the head kidney and spleen after infection with Ichthyophthirius multifiliis (Ich), suggesting that the three Igs might participate in the systemic immune responses to Ich. Moreover, the high expression of IgT in mucosal tissue, such as skin or gills, appeared after being infected with three different pathogens infection, respectively, in which the expression of IgT increased more rapidly in response to Ich infection. Interestingly, the expression of IgD showed a higher increase in spleen and head kidney being challenged with fungi, suggesting that IgD might play an important role in antifungal infection.

Cloning of fatty acid-binding protein 2 (fabp2) in loach (Misgurnus anguillicaudatus) and its expression in response to dietary oxidized fish oil

Fatty acid-binding protein 2 (FABP2) is involved in the uptake of dietary fatty acids and intracellular fatty acid transport. In the present study, cDNA of fabp2 in loach (Misgurnus anguillicaudatus) was cloned and its full length was 956 bp, encoding 134 amino acids. Gene expression of fabp2 was investigated in different development stages and different tissues of loach, showing that the expression of fabp2 was recorded at 2 days after hatching (DAH), 10DAH, 20DAH and 35DAH, and higher in loach intestine, muscle and brain, compared with other tissues. We also investigated the effects of dietary oxidized fish oil (OFO) on the expression of intestinal fabp2 in loach juveniles by using fluorescence in situ hybridization (FISH) and real-time quantitative PCR. Fabp2 gene was expressed mainly by the intestinal epithelium cells of loach juveniles. The expression of intestinal fabp2 in loaches fed with OFO diet was significantly up-regulated on day 1 and 3, and down-regulated on day 10 after feeding, compared with those loaches fed with dietary fresh fish oil (FO), which were in accordance with the fluorescence intensities of FISH exhibiting in the corresponding feeding time. The present study indicated that dietary oxidized fish oil could affect the expression of fabp2 in the loach. Our results serve as reference to better understand the functional characterization of fabp2 in loach and other fish species.

Methods of extraction, separation, purification, structural characterization for polysaccharides from aquatic animals and their major pharmacological activities

The further development of fishery resources is a hotspot in the development of the fishery industry. However, how to develop aquatic animal resources deeply is a key point to be solved in the fishery industry. Over the past decades, numerous aquatic animals have gained great attention in the development and utilization of their bioactive molecules which are of therapeutic applications as nutraceuticals and pharmaceuticals. Recent research revealed that aquatic animals are composed of many vital moieties, such as polysaccharides and proteins, which provide health benefits beyond basic nutrition. In particular, aquatic animal polysaccharides are gaining worldwide popularity owing to their high content, ease of extraction, specific structure, few side effects, prominent therapeutic potential and incorporation in functional foods and dietary supplements. Thus, tremendous research on the isolation, identification and bioactivities of polysaccharides has been carried out. This review presents comprehensive viewpoints on extraction, separation, purification, structural characterization and bioactivity of various polysaccharides from aquatic animals, such as sea cucumber, abalone, oyster and mussels. In addition, this review profiled a brief knowledge on both current challenges and future scope in aquatic animal polysaccharides field. The review will be a direction of deep processing in fishery resources, which is a hotspot, but technical bottleneck. Furthermore, the review could be served as a useful reference material for further investigation, production and application of polysaccharides from aquatic animals in functional foods and therapeutic agents.

Polymeric immunoglobulin receptor in dojo loach (Misgurnus anguillicaudatus): Molecular characterization and expression analysis in response to bacterial and parasitic challenge

The polymeric immunoglobulin receptor (pIgR) is an essential component of the mucosal immune system in jawed vertebrates including teleost fish, which mediate transepithelial transport of secretory immunoglobulins (sIgs) to protect organisms against environmental pathogens. In this study, we firstly cloned and identified the pIgR from dojo loach (Misgurnus anguillicaudatus). The full-length cDNA of Ma-pIgR was of 1145 bp, containing an open reading frame (ORF) of 1101 bp encoded a predicted protein of 336 amino acids. The structure of Ma-pIgR is comprised of a signal peptide, a transmembrane region, an intracellular region and an extracellular region with two Ig-like domains (ILDs), which are similar to their counterparts described in other teleosts. Multiple sequence alignment and phylogenetic analysis showed the dojo loach is closely related to the fish family Cyprinidae. The transcriptional level of Ma-pIgR was detected by quantitative real-time PCR (qRT-PCR) in different tissues and high expression was found in liver, skin, kidney, eye, fin and gills. Two infection models of the loach with bacteria (Aeromonas hydrophila) and parasite (Ichthyophthirius multifiliis) were constructed for the first time. Histological studies showed the goblet cells in skin significantly increased and the ratio of gill length to width also significantly changed after challenged with A.hydrophila. Both challenge experiments resulted in the significant up-regulated expression of Ma-pIgR not only in kidney and spleen, but also in skin and gills. Our results suggest that pIgR may play an important role in skin and gill mucosal immunity to protect the loach against bacteria and parasite.

Toxic effects of glyphosate on diploid and triploid fin cell lines from Misgurnus anguillicaudatus

We examined the toxic effects of glyphosate on diploid (DIMF) and triploid (TRMF) fin cell lines from the Oriental Weather Loach Misgurnus anguillicaudatus. The LC50 values of glyphosate estimated by methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay were 315.34 and 371.77 mg/L for DIMF and TRMF, respectively. Superoxide dismutase (SOD) and glutathione-S-transferase (GST) activities in DIMF and TRMF cells gradually increased and then decreased with increasing glyphosate concentrations, reaching a maximum at 240 mg/L glyphosate. In contrast, acetylcholinesterase (AChE) activities in DIMF and TRMF decreased with increasing concentrations of glyphosate in a concentration-dependent manner. SOD and AChE activities were generally significantly higher in TRMF compared with DIMF cells (P < 0.05). The rates of micronucleus and abnormal nuclei were significantly higher in DIMF and TRMF groups treated with 80-560 mg/L glyphosate compared with the control groups (P < 0.01). The highest micronuclei rates in both DIMF and TRMF cells (both 4.30‰) occurred at 400 mg/L glyphosate. There were no differences in the rates of micronuclei and abnormal nuclei between DIMF and TRMF cells at any glyphosate concentration. Cell damage, including chromatin condensation, nucleus distortion, and broken and reduced endoplasmic reticulum, mitochondria, and ribosomes, were found in both cells treated with the LC50 concentration of glyphosate. Moreover, vacuolization and apoptotic bodies occurred in glyphosate-exposed DIMF and TRMF cells, indicating apoptosis. These results indicate that glyphosate in the range of tested concentrations represent a potential risk to loach through inhibiting proliferation of diploid and triploid cell lines and induces micronuclei and apoptosis.

Establishment and characterization of a skin epidermal cell line from mud loach, Misgurnus anguillicaudatus, (MASE) and its interaction with three bacterial pathogens

A continuous skin epidermal cell line from mud Loach (Misgurnus anguillicaudatus) (MASE cell line) was established with its application in bacteria infection demonstrated in this study. Primary MASE cell culture was initiated at 26 °C in Dulbecco's modified Eagle medium/F12 medium (1:1; pH7.2) supplemented with 20% fetal bovine serum (FBS). The primary MASE cells in spindle morphology proliferated into a confluent monolayer within 2 weeks, and were continuously subcultured even in 10% FBS- DMEM/F12 after 10 passages. Impacts of medium and temperature on the growth of the cells were examined. The optimum growth was found in DMEM/F12 with 20% FBS and at 26 °C. The MASE cells have been subcultured steadily over Passage 90 with a population doubling time of 53.3 h at Passage 60. Chromosome analysis revealed that 60.5% of MASE cells at Passage 60 maintained the normal diploid chromosome number (50) with a normal karyotype of 10m+4sm + 36t. Bacteria from the three species (Aeromonas veronii, Vibrio parahaemolyticus and Escherichia coli) were used to investigate the interactions between bacteria and cellular hosts. The three strains could be attached to the MASE cells and replicate at different levels. A. veronii could induce apoptosis in the MASE cells, with highest adherence rate among the three strains, whereas V. parahaemolyticus could cause highest cell death rate through a non-apoptotic cell death pathway, with high level of replication. The results revealed that different bacteria could interact with the MASE cells in different manners, and divergent pathways might lie in mediating cell death when cellular hosts confronted with pathogen infection. Therefore, the MASE cell line may serve as a useful tool for studying the interaction between skin bacteria and fish cells.

Expression of Immune-Related Genes during Loach (Misgurnus anguillicaudatus) Embryonic and Early Larval Development

Early life stage mortality in fish is one of the problems faced by loach aquaculture. However, our understanding of immune system in early life stage fish is still incomplete, and the information available is restricted to a few fish species. In the present work, we investigated the expression of immune-related transcripts in loach during early development. In fishes, recombination-activating gene 1 (RAG-1) and sacsin (SACS) have been considered as immunological function. In this study, the expression of the both genes was assessed throughout the early developmental stages of loach using real-time PCR method. maRAG-1 mRNA was first detected in 0 dph, observed the increased mostly until 40 dph. Significant expression of maRAG-1 was detected in 0 to 40 dph. These patterns of expression may suggest that the loach start to develop its function after hatching. On the other hand, maSACS was detected in unfertilized oocyte to molura stages and 0 to 40 dph. maSACS mRNA transcripts were detected in unfertilized oocytes, suggesting that they are maternally transferred.

Antioxidant activity and optimization of extraction of polysaccharide from the roots of Dipsacus asperoides

Polysaccharide extraction from Dipsacus asperoides roots (DAP) was proved to possess strong antioxidant activities, including 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-Azobis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical scavenging activities, inhibiting β-carotene bleaching and strong reducing power. Cell assay demonstrated that the crude DAP possessed antioxidant activity and were effective against H2O2-induced L02 cells injury. Then, response surface methodology (RSM) was applied to optimize the ultrasonic extraction of DAP. The optimum variables given by central composite design (CCD) were as follows: ratio of water to raw material, 38.61mL/g; ultrasonic power, 308.68W; extraction time, 38.61min; and extraction temperature, 89°C. Under these conditions, the maximum yield of DAP obtained was 7.12±0.45%. Moreover, high performance liquid chromatography (HPLC) analysis suggested that the monosaccharide compositions of DAP contained primarily mannose, ribose, glucose, galactose, xylose and arabinose, with a molar ratio of 0.22:0.48:2.29:0.34:1.39:1.41. The results of the present study showed that DAP could be considered as potential sources of natural antioxidants.

Transcriptome Profile Analysis of Ovarian Tissues from Diploid and Tetraploid Loaches Misgurnus anguillicaudatus

RNA sequencing and short-read assembly was utilized to produce a transcriptome of ovarian tissues from three-year-old diploid and tetraploid loaches (Misgurnus anguillicaudatus). A total of 28,369 unigenes were obtained, comprising 10,546 unigenes with length longer than 1000 bp. More than 73% of the unigenes were annotated through sequence comparison with databases. The RNA-seq data revealed that 2253 genes were differentially expressed between diploid and tetraploid loaches, including 1263 up-regulated and 990 down-regulated genes in tetraploid loach. Some differentially expressed genes, such as vitellogenin (Vtg), gonadotropin releasing hormone receptor type A (GnRHRA), steroidogenic acute regulatory protein (StAR), mitogen-activated protein kinase 14a (MAPK14a), ATP synthase subunit alpha (atp5a), and synaptonemal complex protein 1 (Scp1), were involved in regulation of cell proliferation, division, gene transcription, ovarian development and energy metabolism, suggesting that these genes were related to egg diameter of the loach. Results of transcriptome profiling here were validated using real time quantitative PCR in ten selected genes. The present study provided insights into the transcriptome profile of ovarian tissues from diploid and tetraploid loaches Misgurnus anguillicaudatus, which was made available to the research community for functional genomics, comparative genomics, polyploidy evolution and molecular breeding of this loach and other related species.

Purification, characterisation and protective effects of polysaccharides from alfalfa on hepatocytes

The objective of this study was to determine the preliminary characteristics and protective effects of alfalfa polysaccharides (APS) on hepatocytes in vitro. The crude APS was purified by DEAE-cellulose and Sephadex G-100 chromatography, resulting in the four purified fractions: APS-1, APS-2, APS-3 and APS-4. The results indicated that APS-3 had higher carbohydrate and uronic acid contents and that APS-4 had a more complicated monosaccharide composition compared to the other purified fractions. The average molecular weights of APS-1, APS-2, APS-3 and APS-4 were 48,536, 6,221, 66,559 and 13,076 Da, respectively. Furthermore, APS (crude and its purified fractions) restored the activities of antioxidant enzymes and increased the total antioxidant capacity of hepatocytes subjected to H2O2-induced oxidative stress. Furthermore, APS treatment counteracted the increases in lactic dehydrogenase and malonaldehyde in the culture supernatant. These results clearly demonstrate that APS possesses a protective effect against oxidative injury in hepatocytes.

Comparative analysis of mitochondrial genomes in distinct nuclear ploidy loach Misgurnus anguillicaudatus and its implications for polyploidy evolution

Misgurnus anguillicaudatus has several natural ploidy types. To investigate whether nuclear polyploidy have an impact on mitochondrial DNA (mtDNA), the complete mitochondrial genomes (mitogenomes) of five distinct ploidy M. anguillicaudatus (natural diploid, triploid, tetraploid, pentaploid and hexaploid), which were collected in central China, were sequenced and analyzed. The five mitogenomes share the same gene arrangement and have similar gene size, base composition and codon usage pattern. The most variable regions of the mitogenome were the protein-coding genes, especially the ND4L (5.39% mutation rate). Most variations occurred in tetraploids. The phylogenetic tree showed that the tetraploid M. anguillicaudatus separated early from other ploidy loaches. Meanwhile, the mitogenomes from pentaploids, and hexaploids have the closest phylogenetic relations, but far from that of tetraploids, implying that pentaploids and hexaploids could not be formed from tetraploids, possibly from the diploids and triploids. The genus Misgurnus species were divided into two divergent inter-genus clades, and the five ploidy M. anguillicaudatus were monophyletic, which support the hypotheses about the mitochondrial introgression in loach species.

Preliminary characterization, antioxidant activity in vitro and hepatoprotective effect on acute alcohol-induced liver injury in mice of polysaccharides from the peduncles of Hovenia dulcis

The fresh fleshy peduncles of Hovenia dulcis have been used as a food supplement and traditional herbal medicine for the treatment of liver diseases and alcoholic poisoning for more than a millennium. The objectives of the present study, therefore, were to determine the antioxidant activity of polysaccharides from the peduncles of H. dulcis (HDPS) and to evaluate its hepatoprotective effect on acute alcohol-induced liver injury in mice. HDPS, prepared by hot water extraction, ethanol precipitation and treatment of macroporous resin, was found to be non-starch polysaccharide and mainly composed of galactose, arabinose, rhamnose and galacturonic acid. In in vitro antioxidant assay, HDPS exhibited high superoxide radical scavenging activity, strong inhibition effect on lipid peroxidation and a medium ferrous ion-chelating activity. For hepatoprotective activity in vivo, the administration of HDPS significantly decreased the serum levels of alanine aminotransferase and aspartate aminotransferase, significantly decreased the liver level of malondialdehyde and remarkably restored the liver activities of superoxide dismutase and glutathione peroxidase in alcohol-induced liver injury mice. The results suggested that HDPS had a significant protective effect against acute alcohol-induced liver injury possibly via its antioxidant activity to protect biological systems against the oxidative stress.

Effect of different dietary zinc levels on hepatic antioxidant and micronutrients indices under oxidative stress conditions

Dietary zinc (Zn) status exerts a powerful influence on the degree of oxidative damage caused by free radicals. We examined the effect of dietary Zn variations with oxidative stress (OS) treatment on antioxidant status, liver function, and status of vitamins in male Wistar rats. Oxidative stress was generated by intraperitoneal injections of tert-butyl hydroperoxide; and dietary Zn variations done were Zn deficient, normal, and excess, with 8, 30, and 60 mg Zn per kilogram diet, respectively. After 21-day dietary regimen, the animals were killed; and plasma aspartate aminotransferase, alanine aminotransferase, hepatic antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase), Zn, reduced glutathione, lipid peroxidation (LPO), and hepatic riboflavin, nicotinic acid, and ascorbic acid estimations were done. The alanine aminotransferase and aspartate aminotransferase levels were elevated in rats with OS and Zn-deficient diet, which were restored to normal levels with excess dietary Zn. Hepatic antioxidant enzymes and reduced glutathione levels were significantly decreased with concomitant increase in LPO due to OS induction in animals with Zn-deficient diet. Corresponding enhanced enzyme activities, higher hepatic Zn, and lowered LPO were observed in animals with normal- and excess-Zn diet. A dose-dependent increase in hepatic nicotinic acid accumulation was observed as the dietary Zn level increased from deficient to excess; however, there was no influence on riboflavin and ascorbic acid status. The results suggest that Zn may have a therapeutic potential in treatment of oxidative liver damage along with enhanced nicotinic acid absorption.

Neuroprotective and antioxidative effect of cactus polysaccharides in vivo and in vitro

Cactus polysaccharides (CP), some of the active components in Opuntia dillenii Haw have been reported to display neuroprotective effects in rat brain slices. In the present study, we investigated the neuroprotective properties of CP and their potential mechanisms on brain ischemia-reperfusion injury in rats, and on oxidative stress-induced damage in PC12 cells. Male Sprague-Dawley rats with ischemia following middle cerebral artery occlusion and reperfusion were investigated. CP (200 mg/kg) significantly decreased the neurological deficit score, reduced infarct volume, decreased neuronal loss in cerebral cortex, and remarkably reduced the protein synthesis of inducible nitric oxide synthase which were induced by ischemia and reperfusion. Otherwise, the protective effect of CP was confirmed in in vitro study. CP protected PC12 cells against hydrogen peroxide (H(2)O(2)) insult. Pretreatment with CP prior to H(2)O(2) exposure significantly elevated cell viability, reduced H(2)O(2)-induced apoptosis, and decreased both intracellular and total accumulation of reactive oxygen species (ROS) production. Furthermore, CP also reversed the upregulation of Bax/Bcl-2 mRNA ratio, the downstream cascade following ROS. These results suggest that CP may be a candidate compound for the treatment of ischemia and oxidative stress-induced neurodegenerative disease.

Comparison of haematology and serum biochemistry of cultured and wild Dojo loach Misgurnus anguillicaudatus

Haematological and serum biochemistry parameters were studied and compared between cultured and wild ecotypes of Dojo loach Misgurnus anguillicaudatus during the prime fishing season, i.e. May-August. Data were analysed for the impact of feeding regime and other ecological conditions on the physiology of fish. The results revealed that haemoglobin, cholesterol, total protein, creatinine and uric acid levels in the two ecotypes were significantly different (n = 56, df = 54, P < 0.05). In addition, red blood cell, glucose, triglyceride and urea nitrogen levels were significantly higher in cultured individuals (n = 56, df = 54, P < 0.01) than in their wild counterparts. In contrast, the white blood cell level in cultured fish was significantly (n = 56, df = 54, P < 0.01) lower than that in the wild ones. These differences can be attributed to the physiological acclimatization of the fish to their living conditions and feeding regime, which influences the energy metabolism and, consequently, the health of the fish.

Antioxidant activities of Sophora subprosrate polysaccharide in immunosuppressed mice

It is known that the reactive oxygen species (ROS) and free radicals play multiple roles in some pathological events. Sophora subprosrate polysaccharide (SSP1), a natural polysaccharide with a mean molecular weight of 2.24 x 10(4), isolated from the roots of Sophora subprosrate was studied for its antioxidant activities in mice. The in vivo investigation demonstrated that intraperitoneal administration of SSP1 was able to overcome cyclophosphamide-induced immunosuppression and significantly raised glutathione level, superoxidase dismutase activity, total antioxidant capacity, thymus and spleen indices in a dose-dependent manner in mice. The results showed that the SSP1, possessing pronounced free radical scavenging and antioxidant activities, may play an important role in prevention of oxidative damage in immunological system.

Haematological characterization of loach Misgurnus anguillicaudatus: comparison among diploid, triploid and tetraploid specimens

The purpose of this study was to determine whether diploid, triploid and tetraploid loach (Misgurnus anguillicaudatus) differed in terms of their main haematological and physiological characteristics. Diploid and tetraploid fish were produced by crossing of natural diploids (2n x 2n) and natural tetraploids (4n x 4n), respectively. Triploid fish were produced by hybridization between diploid males and tetraploid females. The blood cells were significantly larger in polyploids, and the volumetric ratios of erythrocytes and leucocytes (thrombocyte and neutrophil) in tetraploids, triploids and diploids were consistent with the ploidy level ratio of 4:3:2. No significant differences were observed in haematocrit among polyploids. The erythrocyte count decreased with increased ploidy level, while total haemoglobin, mean cell volume, mean cellular haemoglobin content, and mean cell haemoglobin concentration all increased with increase in ploidy level. Erythrocyte osmotic brittleness declined in polyploids so that polyploid erythrocytes were more resistant to osmotic stress than diploid ones. Overall, loach with higher ploidy levels showed evidence of some advantages in haematological characteristics.

In vitro free radical scavenging activities and effect of synthetic oligosaccharides on antioxidant enzymes and lipid peroxidation in aged mice

In this study we synthesized oligosaccharides using glucose as reactant via a route assisted by microwave irradiation and evaluated their antioxidant activity in vivo and in vitro. The results show that the oligosaccharides exhibited antioxidant activity in vitro as compared to standard antioxidants such as butylated hydroxytoluene (BHT), and alpha-tocopherol. This antioxidant activity depended on concentration and increased with increasing dose of sample. In addition, increased endogenous lipid peroxidation and decreased total antioxidant capacity (TAOC) were observed in aged mice. Thirty-day intraperitoneal administration of the oligosaccharides significantly decreased the lipid peroxidation in a dose-dependent manner. Oligosaccharides treatment increased TAOC and the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in all organs tested in aged mice. The present study suggests that the synthetic oligosaccharides possess promising future for their strong free radical scavenging activity. Therefore they can be employed in compensating the decline in TAOC and the activities of antioxidant enzymes and in reducing the risks of lipid peroxidation.

Antioxidant properties of the mucus secreted by Laeonereis acuta (Polychaeta, Nereididae): a defense against environmental pro-oxidants?

Polychaeta species like Laeonereis acuta (Nereididae) usually secrete great amounts of mucus that wrap the animal inside. Taking into account that fungi action in the sediment and UV radiation acting on dissolved organic matter in the water produces reactive oxygen species (ROS) like hydrogen peroxide (H(2)O(2)), it was considered that the mucus secretion could represent an antioxidant defense against environmental ROS. Antioxidant enzymes (catalase-CAT; superoxide dismutase-SOD; glutathione peroxidase-GPx and glutathione-S-transferase-GST) and total antioxidant capacity (TOSC) were determined in worms and mucus secretion. Higher (p<0.05) CAT, GPx and TOSC values were registered in mucus samples respect worms, SOD activity was similar (p>0.05) in both kind of samples, and absence of GST activity was observed in mucus samples, suggesting absence of catalyzed phase II reactions. In assays conducted with hepatoma cell lines exposed to H(2)O(2), it was verified that: (1) mucus co-exposure significantly (p<0.05) lowered DNA damage induced by H(2)O(2); (2) ROS production was significantly (p<0.05) reduced when cells were exposed simultaneously with mucus samples and H(2)O(2) respect H(2)O(2) alone. It can be concluded that the mucus production contributes substantially to the antioxidant defense system of the worm against environmental ROS through the interception or degradation of H(2)O(2), peroxyl and hydroxyl radicals.

Sulfation of a polysaccharide produced by a marine filamentous fungus Phoma herbarum YS4108 alters its antioxidant properties in vitro

Free radicals and other reactive oxygen species (ROS) are generated by all aerobic cells and are widely believed to play a significant role in aging as well as a number of degenerative or pathological diseases. This study compared the free radical-scavenging properties and antioxidant activity of YCP, a polysaccharide from the mycelium of a marine filamentous fungus Phoma herbarum YS 4108 and its two chemically sulfated derivatives YCP-S1 and YCP-S2. Sulfation, which masks hydroxyl groups of YCP polysaccharide molecule, could introduce new antioxidant activity, such as superoxide and hydroxyl radicals scavenging activity, metal chelating action, lipid peroxidation and linoleic acid oxidation inhibition capability. Furthermore, sulfated YCP was more potent than YCP at protecting erythrocytes against oxidative damage hemolysis. The current data suggest for the first time that sulfation of polysaccharide significantly increases its antioxidant activity and the chemical modification of polysaccharides may allow the preparation of derivatives with new properties and a variety of applications.

Apoptosis induction on HL-60 cells of a novel polysaccharide from the mucus of the loach, Misgurnus anguillicaudatus

This study was designed to determine the anti-proliferative, apoptotic properties of a novel polysaccharide from the loach, Misgurnus anguillicaudatus (MAP), using a human promyelocytic leukemia line (HL-60) as a model system. HL-60 cells were cultured in the presence of MAP at various concentrations (50-800 mg/l) for 5 days and the percentage of cell viability was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The results showed that MAP inhibited the cells viability in time and concentration-dependent characteristics. We found that anti-proliferative effect of MAP was associated with apoptosis on HL-60 cells by determinations of morphological changes and oligonucleosomal DNA fragments. In addition, the content of nitric oxide (NO) and activity of lactate dehydrogenase (LDH) release increased when the cells incubated with MAP at various concentrations and times. These investigations suggest that the polysaccharide from loach has the function of anti-proliferation and induction of apoptosis in tumor cells in vitro.

Protection of PC12 cells from hydrogen peroxide-induced injury by EPS2, an exopolysaccharide from a marine filamentous fungus Keissleriella sp. YS4108

A number of studies indicate that free radicals are involved in the neurodegeneration in Parkinson's and Alzheimer's diseases. EPS2, an exopolysaccharide with a mean molecular weight of 1.3 x 10(5) Da, was isolated by ion-exchange and sizing chromatography from the culture of Keissleriella sp. YS4108, a marine filamentous fungus. Compositionally, it is composed of galactose, glucose, rhamnose, mannose and glucuronic acid in an approximate proportion of 50:8:1:1:0.4. The protective effects of EPS2 on peroxide hydrogen (H2O2)-induced cell lesion, level of lipid peroxidation, antioxidant enzyme activities were investigated in the rat pheochromocytoma line PC12 cells. Following a 1-h exposure of the cells to H2O2, a significant reduction in cell survival and activities of glutathione peroxidase (GSH-Px) and catalase (CAT), as well as increased levels in malondialdehyde (MDA) production and lactate dehydrogenase (LDH) release were observed. However, preincubation of the cells with EPS2 prior to H2O2 exposure elevated the cell survival and GSH-Px and CAT activities, and decreased the level of MDA and LDH activity in a dose-dependent manner. In conclusion, EPS2 possesses pronounced protective effects against H2O2-induced cell toxicity. The finding is of a higher value in searching for new therapeutic agent for treating oxidative damage-derived neurodegenerative disorders.

Free radical scavenging and antioxidant activities of EPS2, an exopolysaccharide produced by a marine filamentous fungus Keissleriella sp. YS 4108

The reactive oxygen species (ROS) and free radical-initiated reactions are ascertained to play multiple roles in degenerative or pathological events such as aging, cancer, heart dysfunction and Alzheimer's disease. EPS2 with a mean molecular weight of 1.3 x 10(5) was characterized as an antioxidant exopolysaccharide from the broth of a marine filamentous fungus Keissleriella sp. YS 4108. Compositionally, it is composed of galactose, glucose, rhamnose, mannose and glucuronic acid in an approximate proportion of 50:8:1:1:0.4. The radical eliminating and antioxidant actions of the glycan was assessed in different in vitro systems showing that EPS2 exhibited profound scavenging activities in superoxide radical. As a reinforcement of the action, similar radical scavenging effects of EPS2 were also discerned with both site-specific and non site-specific hydroxyl radical using the deoxyribose assay method. Moreover, EPS2 effectively blocked as well the non site-specific strand-breaking of DNA induced by the Fenton reaction at concentrations of 0.1 and 1 mg/mL. Further investigation of the effect of EPS2 on human low density lipoprotein (LDL) system demonstrated that it significantly inhibited copper-mediated oxidation of LDL in a dose-dependent manner. These results suggest that EPS2, possessing pronounced free radical scavenging and antioxidant activities, could be of considerable preventive and therapeutic significance to some life-threatening health problems such as cancer, atherogenesis and Alzheimer's disease which pathologically initiated by the presence of free radicals leading to the inevitable peroxidation of important biomolecules.