MicroRNA sequencing analysis reveals immune responses in hepatopancreas of Fenneropenaeus penicillatus under white spot syndrome virus infection.

White Spot Disease is one of the most harmful diseases of the red tail shrimp, which can cause devastating economic losses due to the highest mortality up to 100% within a few days. MicroRNAs (miRNAs) are large class of small noncoding RNAs with the ability to post-transcriptionally repress the translation of target mRNAs. MiRNAs are considered to have a significant role in the innate immune response of crustaceans, particularly in relation to antiviral defense mechanisms. Numerous crustacean miRNAs have been verified to be required in host immune defense against viral infection, however, till present, the miRNAs functions of F. penicillatus defense WSSV infection have not been studied yet. Here in this study, for the first time, miRNAs involved in the F. penicillatus immune defense against WSSV infection were identified using high-throughput sequencing platform. A total of 432 miRNAs were obtained including 402 conserved miRNAs and 30 novel predicted miRNAs. Comparative analysis between the WSSV-challenged group and the control group revealed differential expression of 159 microRNAs in response to WSSV infection. Among these, 48 were up-regulated and 111 were down-regulated. Ten candidate MicroRNAs associated with immune activities were randomly selected for qRT-PCR analysis, which confirming the expression profiling observed in the MicroRNA sequencing data. As a result, most differentially expressed miRNAs were down-regulated lead to increase the expression of various target genes that mediated immune reaction defense WSSV infection, including genes related to signal transduction, Complement and coagulation cascade, Phagocytosis, and Apoptosis. Furthermore, the genes expression of the key members in Toll and Imd signaling pathways and apoptotic signaling were mediated by microRNAs to activate host immune responses including apoptosis against WSSV infection. These results will help to understand molecular defense mechanism against WSSV infection in F. penicillatus and to develop an effective WSSV defensive strategy in shrimp farming.

New Cyclic Pentapeptides from the Mangrove-Derived Aspergillus fumigatus GXIMD 03099.

Four new cyclic pentapeptides, avellanins D-G (1-4), together with four known compounds (5-8), were isolated from a mangrove-derived Aspergillus fumigatus GXIMD 03099 fungus from Acanthus ilicifolius L. Their structures were elucidated by analysis of HRESIMS, NMR, and ESI-MS/MS data. Their absolute configurations were determined by X-ray diffraction analysis and Marfey's method. Compounds 1-8 were screened for insecticidal and antibacterial activities. Compound 2 showed insecticidal activity against newly hatched larvae of Culex quinquefasciatus with an LC50 value of 86.6 µM; compound 4 had weak activity against Vibrio harveyi with an MIC value of 5.85 µM.

18-Residue Peptaibols Produced by the Sponge-Derived Trichoderma sp. GXIMD 01001.

Seven new 18-residue peptaibols, trichorzins A-G (1-7), were isolated from the sponge-derived fungus Trichoderma sp. GXIMD 01001. Their structures and configurations were characterized by a comprehensive interpretation of the NMR spectroscopic data, MS/MS fragmentation, Marfey's method, and ECD analysis. The general sequences of trichorzins A-G are as follows: Ac-Aib1-Ala/Ser2-Ala3-Aib/Iva4-Iva5-Gln6-Aib/Iva7-Val/allo-Ile8-Aib9-Gly10-Leu11-Aib12-Pro13-Leu14-Aib15-Aib16-Gln17-Trpol/Pheol18. The obtained compounds were assessed for their potential antiproliferative and antimicrobial activities. All obtained compounds did not show potent antibacterial activity but exhibited significant cytotoxicity, with the lowest IC50 values at 0.46-4.7 µM against four human carcinoma cell lines.

Chondroitin Sulfate/Dermatan Sulfate Hybrid Chains from Swim Bladder: Isolation, Structural Analysis, and Anticoagulant Activity.

Glycosaminoglycans (GAGs) with unique structures from marine animals show intriguing pharmacological activities and negligible biological risks, providing more options for us to explore safer agents. The swim bladder is a tonic food and folk medicine, and its GAGs show good anticoagulant activity. In this study, two GAGs, CMG-1.0 and GMG-1.0, were extracted and isolated from the swim bladder of Cynoscion microlepidotus and Gadus morhua. The physicochemical properties, precise structural characteristics, and anticoagulant activities of these GAGs were determined for the first time. The analysis results of the CMG-1.0 and GMG-1.0 showed that they were chondroitin sulfate (CS)/dermatan sulfate (DS) hybrid chains with molecular weights of 109.3 kDa and 123.1 kDa, respectively. They were mainly composed of the repeating disaccharide unit of -{IdoA-α1,3-GalNAc4S-ß1,4-}- (DS-A). The DS-B disaccharide unit of -{IdoA2S-α1,3-GalNAc4S-ß1,4-}- also existed in both CMG-1.0 and GMG-1.0. CMG-1.0 had a higher proportion of CS-O disaccharide unit -{-GlcA-ß1,3-GalNAc-ß1,4-}- but a lower proportion of CS-E disaccharide unit -{-GlcA-ß1,3-GalNAc4S6S-ß1,4-}- than GMG-1.0. The disaccharide compositions of the GAGs varied in a species-specific manner. Anticoagulant activity assay revealed that both CMG-1.0 and GMG-1.0 had potent anticoagulant activity, which can significantly prolong activated partial thromboplastin time. GMG-1.0 also can prolong the thrombin time. CMG-1.0 showed no intrinsic tenase inhibition activity, while GMG-1.0 can obviously inhibit intrinsic tenase with EC50 of 58 nM. Their significantly different anticoagulant activities may be due to their different disaccharide structural units and proportions. These findings suggested that swim bladder by-products of fish processing of these two marine organisms may be used as a source of anticoagulants.

Structural Elucidation of a Glucan from Trichaster palmiferus by Its Degraded Products and Preparation of Its Sulfated Derivative as an Anticoagulant.

Echinoderms have been attracting increasing attention for their polysaccharides, with unique chemical structure and enormous potential for preparing drugs to treat diseases. In this study, a glucan (TPG) was obtained from the brittle star Trichaster palmiferus. Its structure was elucidated by physicochemical analysis and by analyzing its low-molecular-weight products as degraded by mild acid hydrolysis. The TPG sulfate (TPGS) was prepared, and its anticoagulant activity was investigated for potential development of anticoagulants. Results showed that TPG consisted of a consecutive α1,4-linked D-glucopyranose (D-Glcp) backbone together with a α1,4-linked D-Glcp disaccharide side chain linked through C-1 to C-6 of the main chain. The TPGS was successfully prepared with a degree of sulfation of 1.57. Anticoagulant activity results showed that TPGS significantly prolonged activated partial thromboplastin time, thrombin time, and prothrombin time. Furthermore, TPGS obviously inhibited intrinsic tenase, with an EC50 value of 77.15 ng/mL, which was comparable with that of low-molecular-weight heparin (LMWH) (69.82 ng/mL). TPGS showed no AT-dependent anti-FIIa and anti-FXa activities. These results suggest that the sulfate group and sulfated disaccharide side chains play a crucial role in the anticoagulant activity of TPGS. These findings may provide some information for the development and utilization of brittle star resources.

Physicochemical Properties and Anticoagulant Activity of Purified Heteropolysaccharides from Laminaria japonica.

Laminaria japonica is widely consumed as a key food and medicine. Polysaccharides are one of the most plentiful constituents of this marine plant. In this study, several polysaccharide fractions with different charge numbers were obtained. Their physicochemical properties and anticoagulant activities were determined by chemical and instrumental methods. The chemical analysis showed that Laminaria japonica polysaccharides (LJPs) and the purified fractions LJP0, LJP04, LJP06, and LJP08 mainly consisted of mannose, glucuronic acid, galactose, and fucose in different mole ratios. LJP04 and LJP06 also contained minor amounts of xylose. The polysaccharide fractions eluted by higher concentration of NaCl solutions showed higher contents of uronic acid and sulfate group. Biological activity assays showed that LJPs LJP06 and LJP08 could obviously prolong the activated partial thromboplastin time (APTT), indicating that they had strong anticoagulant activity. Furthermore, we found that LJP06 exerted this activity by inhibiting intrinsic factor Xase with higher selectivity than other fractions, which may have negligible bleeding risk. The sulfate group may play an important role in the anticoagulant activity. In addition, the carboxyl group and surface morphology of these fractions may affect their anticoagulant activities. The results provide information for applications of L. japonica polysaccharides, especially LJP06 as anticoagulants in functional foods and therapeutic agents.

Structural Characterization and Heparanase Inhibitory Activity of Fucosylated Glycosaminoglycan from Holothuria floridana.

Unique fucosylated glycosaminoglycans (FG) have attracted increasing attention for various bioactivities. However, the precise structures of FGs usually vary in a species-specific manner. In this study, HfFG was isolated from Holothuria floridana and purified by anion exchange chromatography with the yield of ~0.9%. HfFG was composed of GlcA, GalNAc and Fuc, its molecular weight was 47.3 kDa, and the -OSO3-/-COO- molar ratio was 3.756. HfFG was depolymerized by a partial deacetylation-deaminative cleavage method to obtain the low-molecular-weight HfFG (dHfFG). Three oligosaccharide fragments (Fr-1, Fr-2, Fr-3) with different molecular weights were isolated from the dHfFG, and their structures were revealed by 1D and 2D NMR spectroscopy. HfFG should be composed of repeating trisaccharide units -{(L-FucS-α1,3-)d-GlcA-ß1,3-d-GalNAc4S6S-ß1,4-}-, in which sulfated fucose (FucS) includes Fuc2S4S, Fuc3S4S and Fuc4S residues linked to O-3 of GlcA in a ratio of 45:35:20. Furthermore, the heparanase inhibitory activities of native HfFG and oligosaccharide fragments (Fr-1, Fr-2, Fr-3) were evaluated. The native HfFG and its oligosaccharides exhibited heparanase inhibitory activities, and the activities increased with the increase of molecular weight. Additionally, structural characteristics such as sulfation patterns, the terminal structure of oligosaccharides and the presence of fucosyl branches may be important factors affecting heparanase inhibiting activity.

Oligosaccharides from depolymerized fucosylated glycosaminoglycan: Structures and minimum size for intrinsic factor Xase complex inhibition.

Fucosylated glycosaminoglycan (FG), a structurally complex glycosaminoglycan found up to now exclusively in sea cucumbers, has distinct anticoagulant properties, notably a strong inhibitory activity of intrinsic factor Xase complex (FXase). Knowledge of the FG structures could facilitate the development of a clinically effective intrinsic FXase inhibitor for anticoagulant drugs. Here, a new fucosylated glycosaminoglycan was obtained from the widely traded sea cucumber Bohadschia argus The precise structure was deduced as {→4)-[l-Fuc3S4S-α-(1→3)-]-d-GlcA-ß-(1→3)-d-GalNAc4S6S-ß-(1} through analysis of its chemical properties and homogeneous oligosaccharides purified from its ß-eliminative depolymerized products. The B. argus FG with mostly 3,4-di-O-sulfated fucoses expands our knowledge on FG structural types. This ß-elimination process, producing oligosaccharides with well-defined structures, is a powerful tool for analyzing the structure of complex FGs. Among these oligosaccharides, an octasaccharide displayed potent FXase inhibitory activity. Compared with oligosaccharides with various degrees of polymerization (3n and 3n - 1), our analyses reveal that the purified octasaccharide is the minimum structural unit responsible for the potent selective FXase inhibition, because the d-talitol in the nonsaccharide is unnecessary. The octasaccharide with 2,4-di-O-sulfated fucoses is more potent than that of one with 3,4-di-O-sulfated fucoses. Thus, sulfation patterns can play an important role in the inhibition of intrinsic factor Xase complex.

Precise Structure and Anticoagulant Activity of Fucosylated Glycosaminoglycan from Apostichopus japonicus: Analysis of Its Depolymerized Fragments.

Apostichopus japonicus is one of the most economically important species in sea cucumber aquaculture in China. Fucosylated glycosaminoglycan from A. japonicus (AjFG) has shown multiple pharmacological activities. However, results from studies on the structure of AjFG are still controversial. In this study, the deaminative depolymerization method that is glycosidic bond-selective was used to prepare the depolymerized products from AjFG (dAjFG), and then a series of purified oligosaccharide fragments such as tri-, hexa-, nona-, and dodecasaccharides were obtained from dAjFG by gel permeation chromatography. The 1D/2D NMR and ESI-MS spectrometry analyses showed that these oligosaccharides had the structural formula of l-FucS-α1,3-d-GlcA-ß1,3-{d-GalNAc4S6S-ß1,4-[l-FucS-α1,3-]d-GlcA-ß1,3-}n-d-anTal-diol4S6S (n = 0, 1, 2, 3; FucS represents Fuc2S4S, Fuc3S4S, or Fuc4S). Thus, the unambiguous structure of native AjFG can be rationally deduced: it had the backbone of {-4-d-GlcA-ß1,3-d-GalNAc4S6S-ß1-}n, which is similar to chondroitin sulfate E, and each d-GlcA residue in the backbone was branched with a l-FucS monosaccharide at O-3. Bioactivity assays confirmed that dAjFG and nonasaccharides and dodecasaccharides from AjFG had potent anticoagulant activity by intrinsic FXase inhibition while avoiding side effects such as FXII activation and platelet aggregation.

Physicochemical Characteristics and Anticoagulant Activities of the Polysaccharides from Sea Cucumber Pattalus mollis.

Sulfated polysaccharides from sea cucumbers possess distinct chemical structure and various biological activities. Herein, three types of polysaccharides were isolated and purified from Pattalus mollis, and their structures and bioactivities were analyzed. The fucosylated glycosaminoglycan (PmFG) had a CS-like backbone composed of the repeating units of {-4-d-GlcA-ß-1,3-d-GalNAc4S6S-ß-1-}, and branches of a sulfated α-l-Fuc (including Fuc2S4S, Fuc3S4S and Fuc4S with a molar ratio of 2:2.5:1) linked to O-3 of each d-GlcA. The fucan sulfate (PmFS) had a backbone consisting of a repetitively linked unit {-4-l-Fuc2S-α-1-}, and interestingly, every trisaccharide unit in its backbone was branched with a sulfated α-l-Fuc (Fuc4S or Fuc3S with a molar ratio of 4:1). Apart from the sulfated polysaccharides, two neutral glycans (PmNG-1 & -2) differing in molecular weight were also obtained and their structures were similar to animal glycogen. Anticoagulant assays indicated that PmFG and PmFS possessed strong APTT prolonging and intrinsic factor Xase inhibition activities, and the sulfated α-l-Fuc branches might contribute to the anticoagulant and anti-FXase activities of both PmFG and PmFS.

Discovery of an intrinsic tenase complex inhibitor: Pure nonasaccharide from fucosylated glycosaminoglycan.

Selective inhibition of the intrinsic coagulation pathway is a promising strategy for developing safer anticoagulants that do not cause serious bleeding. Intrinsic tenase, the final and rate-limiting enzyme complex in the intrinsic coagulation pathway, is an attractive but less explored target for anticoagulants due to the lack of a pure selective inhibitor. Fucosylated glycosaminoglycan (FG), which has a distinct but complicated and ill-defined structure, is a potent natural anticoagulant with nonselective and adverse activities. Herein we present a range of oligosaccharides prepared via the deacetylation-deaminative cleavage of FG. Analysis of these purified oligosaccharides reveals the precise structure of FG. Among these fragments, nonasaccharide is the minimum fragment that retains the potent selective inhibition of the intrinsic tenase while avoiding the adverse effects of native FG. In vivo, the nonasaccharide shows 97% inhibition of venous thrombus at a dose of 10 mg/kg in rats and has no obvious bleeding risk. This nonasaccharide may therefore serve as a novel promising anticoagulant.

Enzyme-Assisted Extraction Optimization, Characterization and Antioxidant Activity of Polysaccharides from Sea Cucumber Phyllophorus proteus.

Enzyme-assisted extraction optimization, characterization and in vitro antioxidant activity of polysaccharides from sea cucumber Phyllophorus proteus (PPP) were investigated in the present study. The optimal extraction conditions with a yield of 6.44 ± 0.06% for PPP were determined as follows: Extraction time of 2.89 h, ratio of extraction solvent to raw material of 16.26 mL/g, extraction pH of 6.83, exraction temperature of 50 °C and papain concentration of 0.15%. Three purified fractions, PPP-1a, PPP-1b and PPP-2 with molecular weights of 369.60, 41.73 and 57.76 kDa, respectively, were obtained from PPP by chromatography of FPA98Cl and Sepharose CL-6B columns. Analysis of monosaccharide compositions showed that PPP-1a consisted of N-acetyl-galactosamine (GalNAc), galactose (Gal) and fucose (Fuc), PPP-1b of Fuc as the only monosaccharide and PPP-2 of glucuronic acid, GalNAc and Fuc. Sulfate contents of PPP, PPP-1a, PPP-1b and PPP-2 were determined to be 21.9%, 20.6%, 25.2% and 28.0% (w/w), respectively. PPP and PPP-1a had higher molecular weight and intrinsic viscosity than those of the PPP-1b and PPP-2. PPP, PPP-1a, PPP-1b and PPP-2 exhibited obvious activities of scavenging 1,1-diphenyl-2-picrylhydrazyl radical, hydroxyl radical, superoxide radical and ABTS radical in different extent, which suggested that the polysaccharides from Phyllophorus proteus may be novel agents having potential value for antioxidation.

Structural analysis and anticoagulant activities of the novel sulfated fucan possessing a regular well-defined repeating unit from sea cucumber.

Sulfated fucans, the complex polysaccharides, exhibit various biological activities. Herein, we purified two fucans from the sea cucumbers Holothuria edulis and Ludwigothurea grisea. Their structures were verified by means of HPGPC, FT-IR, GC-MS and NMR. As a result, a novel structural motif for this type of polymers is reported. The fucans have a unique structure composed of a central core of regular (1→2) and (1→3)-linked tetrasaccharide repeating units. Approximately 50% of the units from L. grisea (100% for H. edulis fucan) contain sides of oligosaccharides formed by nonsulfated fucose units linked to the O-4 position of the central core. Anticoagulant activity assays indicate that the sea cucumber fucans strongly inhibit human blood clotting through the intrinsic pathways of the coagulation cascade. Moreover, the mechanism of anticoagulant action of the fucans is selective inhibition of thrombin activity by heparin cofactor II. The distinctive tetrasaccharide repeating units contribute to the anticoagulant action. Additionally, unlike the fucans from marine alga, although the sea cucumber fucans have great molecular weights and affluent sulfates, they do not induce platelet aggregation. Overall, our results may be helpful in understanding the structure-function relationships of the well-defined polysaccharides from invertebrate as new types of safer anticoagulants.

Recent progress in marine chondroitin sulfate, dermatan sulfate, and chondroitin sulfate/dermatan sulfate hybrid chains as potential functional foods and therapeutic agents.

Chondroitin sulfate (CS), dermatan sulfate (DS), and CS/DS hybrid chains are natural complex glycosaminoglycans with high structural diversity and widely distributed in marine organisms, such as fish, shrimp, starfish, and sea cucumber. Numerous CS, DS, and CS/DS hybrid chains with various structures and activities have been obtained from marine animals and have received extensive attention. However, only a few of these hybrid chains have been well-characterized and commercially developed. This review presents information on the extraction, purification, structural characterization, biological activities, potential action mechanisms, and structure-activity relationships of marine CS, DS, and CS/DS hybrid chains. We also discuss the challenges and perspectives in the research of CS, DS, and CS/DS hybrid chains. This review may provide a useful reference for the further investigation, development, and application of CS, DS, and CS/DS hybrid chains in the fields of functional foods and therapeutic agents.

Structural analysis and in vitro fermentation characteristics of an Avicennia marina fruit RG-I pectin as a potential prebiotic.

Avicennia marina (Forssk.) Vierh. is a highly salt-tolerant mangrove, and its fruit has been traditionally used for treating constipation and dysentery. In this study, a pectin (AMFPs-0-1) was extracted and isolated from this fruit for the first time, its structure was analyzed, and the effects on the human gut microbiota were investigated. The results indicated that AMFPs-0-1 with a molecular weight of 798 kDa had a backbone consisting of alternating →2)-α-L-Rhap-(1→ and →4)-α-D-GalpA-(1→ residues and side chains composed of →3-α-L-Araf-(1→-linked arabinan with a terminal ß-L-Araf, →5-α-L-Araf-(1→-linked arabinan, and →4)-ß-D-Galp-(1→-linked galactan that linked to the C-4 positions of all α-L-Rhap residues in the backbone. It belongs to a type I rhamnogalacturonan (RG-I) pectin but has no arabinogalactosyl chains. AMFPs-0-1 could be consumed by human gut microbiota and increase the abundance of some beneficial bacteria, such as Bifidobacterium, Mitsuokella, and Megasphaera, which could help fight digestive disorders. These findings provide a structural basis for the potential application of A. marina fruit RG-I pectic polysaccharides in improving human intestinal health.

Chromosomal-level genome assembly and annotation of the tropical sea cucumber Holothuria scabra.

Holothuria scabra, a commercially valuable yet ecologically vulnerable tropical holothuroid, has experienced a severe decline in its wild populations, especially in China. Genomic resources are crucial for the development of effective genomic breeding projects and stock conservation strategies to restore these natural populations. Until now, a high-quality, chromosome-level reference genome for H. scabra has not been available. Here, we employed Oxford Nanopore and Hi-C sequencing technologies to assemble and annotate a high-quality, chromosome-level reference genome of H. scabra. The final genome comprised 31 scaffolds with a total length of 1.19 Gb and a scaffold N50 length of 53.52 Mb. Remarkably, 1,191.67 Mb (99.95%) of the sequences were anchored to 23 pseudo-chromosomes, with the longest one spanning 79.75 Mb. A total of 34,418 protein-coding genes were annotated in the final genome, with BUSCO analysis revealing 98.01% coverage of metazoa_odb10 genes, marking a significant improvement compared to the previous report. These chromosome-level sequences and annotations will provide an essential genomic basis for further investigation into molecular breeding and conservation management of H. scabra.

Structural characterization of a Chlorella heteropolysaccharide by analyzing its depolymerized product and finding an inducer of human dendritic cell maturation.

Chlorella polysaccharides have been gaining increasing attention because of their high yield from dried Chlorella powder and their remarkable immunomodulatory activity. In this study, the major polysaccharide fraction, CPP-3a, in Chlorella pyrenoidosa, was isolated, and its detailed structure was investigated by analyzing the low-molecular-weight product prepared via free radical depolymerization. The results indicated that CPP-3a with a molecular weight of 195.2 kDa was formed by →2)-α-L-Araf-(1→, →2)-α-D-Rhap-(1→, →5)-α-L-Araf-(1→, →3)-ß-D-Glcp-(1→, →4)-α-D-Glcp-(1→, →4)-α-D-GlcpA-(1→, →2,3)-α-D-Manp-(1→, →3,4)-α-D-Manp-(1→, →3,4)-ß-D-Galp-(1→, →3,6)-ß-D-Galp-(1→, and →2,3,6)-α-D-Galp-(1→ residues, branched at C2, C3, C4, or C6 of α/ß-D-Galp and α-D-Manp, and terminated by α/ß-L-Araf, α-L-Arap, α-D-Galp, and ß-D-Glcp. Biological assays showed that CPP-3a significantly altered the dendritic morphology of immature dendritic cells (DCs). Enhanced CD80, CD86, and MHC I expression on the cell surface and decreased phagocytic ability indicated that CPP-3a could induce the maturation of DCs. Furthermore, CPP-3a-stimulated DCs not only stimulated the proliferation of allogeneic naïve CD4+ T cells and the secretion of IFN-γ, but also directly stimulated the activation and proliferation of CD8+ T cells through cross-antigen presentation. These findings indicate that CPP-3a can promote human DC maturation and T-cell stimulation and may be a novel DC maturation inducer with potential developmental value in DC immunotherapy.

A regular Chlorella mannogalactan and its sulfated derivative as a promising anticoagulant: Structural characterization and anticoagulant activity.

Chlorella is one of the most widely cultivated species of microalgae and has been consumed as a "green healthy food". In this study, a novel polysaccharide (CPP-1) was isolated from Chlorella pyrenoidosa, structurally analyzed, and sulfated as a promising anticoagulant. Structural analyses by chemical and instrumental methods such as monosaccharide composition, methylation-GC-MS and 1D/2D NMR spectroscopy analysis revealed that CPP-1 had a molecular weight of ~13.6 kDa, and mainly consisted of d-mannopyranose (d-Manp), 3-O-methylated d-Manp (3-O-Me-d-Manp), and d-galactopyranose (d-Galp). The molar ratio of d-Manp and d-Galp was 1.0:2.3. CPP-1 consisted of a (1→6)-linked ß-d-Galp backbone substituted at C-3 by the d-Manp and 3-O-Me-d-Manp residues in a molar ratio of 1:1, which was a regular mannogalactan. The sulfated Chlorella mannogalactan (SCM) with sulfated group content of 40.2 % equivalent to that of unfractionated heparin was prepared and analyzed. NMR analysis confirmed its structure, indicating that most free hydroxyl groups in the side chains and partial hydroxyl groups in the backbone were sulfated. Anticoagulant activity assays indicated that SCM exhibited strong anticoagulant activity by inhibiting intrinsic tenase (FXase) with IC50 of 13.65 ng/mL, which may be a safer anticoagulant as an alternative to heparin-like drugs.

The first completed genome of species Prevotella bivia, assembled from a clinically derived strain PLW0727.

OBJECTIVES: Prevotella bivia is a species that commonly colonizes various human body sites, and it is associated with lots of human infections. However, until now, no complete genome sequence of this species has been published. Here, we assembled the first complete genome of P. bivia from a clinically derived strain PLW0727, to characterize its general genomic features, and to profile the capacity in encoding antibiotic resistance and virulence factors. METHODS: Whole-genome sequencing was performed using Illumina and Nanopore platforms. Hybrid assembly was conducted using flye v2.9.1 and Unicycler v0.4.9b. Assembly completeness was assessed using CheckM v1.0.12. Comprehensive genome annotation was performed using eggNOG-mapper v2.1.5 and PATRIC v3.6.10. RESULTS: The complete genome of PLW0727 consists of two circular chromosomes, chr1 and chr2, exhibiting a completeness of 99.66%, a G+C content of 39.5%, and a total size of 2.43 Mb. Chr1 and chr2 have lengths of 1 272 652 bp and 1 155 021 bp, harbouring 1 132 CDSs and 1 055 CDSs, respectively. Completion of the genome significantly reduced the proportion of hypothetical CDS annotations compared with the draft genomes. A gene-encoding antibiotic resistance to beta-lactams (i.e., cfxA3) has been annotated in chr2. By providing the genome sequence, strain PLW0727 was identified as a human pathogen with a probability of 0.614 using the PathogenFinder. Furthermore, genes involved in virulence-related functions, including host cell adherence and capsule immune modulation were also annotated. CONCLUSIONS: This study assembles the first complete genome for P. bivia, providing valuable genomic insights into its phylogeny, pathogenicity, and antibiotic resistance. These findings have important implications for the clinical management and prevention of P. bivia infections.

[Immunomodulatory effects of Opuntia dillenii polysaccharides on specific immune function of mice].

OBJECTIVE: To investigate specific immune modulation of Opuntia dillenii polysaccharides (ODPs) on mice (body fluid and cells). METHODS: An immunosuppressed murine model was induced by intraperitoneal injection of cyclophosphamide (Cy, ip). The intraserous hemolysin IgM, IgG levels, the proliferation of spenocytes and the proportion of T lymphocyte subsets in peripheral blood were determined after the mice treated by ODPs. Proliferative effects of ODP-I, the main component purified from ODPs, on the lymphocytes in vitro were also studied. RESULTS: ODPs could significantly increase intraserous IgM and IgG levels, significantly enhance the proliferation of T and B lymphocytes and restore them to normal level. ODPs significantly reduced the percentage of CD4+ T lymphocytes subset, therefore significantly reduced the proportion of CD4+ and CD8+ T lymphocytes of peripheral blood from immunosuppressive mice and restored it to normal level. ODP-I significantly enhanced the natural proliferation of splenic lymphocyte and assisted the proliferation of T and B lymphocytes which induced by mitogen ConA or LPS. CONCLUSION: ODPs can enhance the specific immune function of immunosuppressed mice and the proliferation of lymphocytes in vitro.