Rab1A functioned as a binding protein involved in Macrobrachium rosenbergii Taihu virus infection.

Macrobrachium rosenbergii Taihu virus (MrTV) is a virulent pathogen that mainly threatens M. rosenbergii larvae. Rab proteins, which are essential for controlling intracellular membrane trafficking, are hijacked by multiple viruses to complete their life cycle. In this paper, we studied the function of M. rosenbergii Rab1A (MrRab1A) in the MrTV infection. Upon MrTV infection, the transcription level of MrRab1A was significantly up-regulated, indicating MrRab1A was a MrTV responsive gene and might be important for MrTV infection. Co-IP and co-localization assays revealed that MrRab1A could directly bind with MrTV and its capsid protein VP3. Moreover, the in vivo neutralization assay demonstrated that pre-incubation of MrTV with recombinant MrRab1A could partially block MrTV infection. These findings indicated that MrRab1A functioned as a virus-binding protein involved in MrTV infection, which shed new light on the mechanism of MrTV infection and provided a potential target for developing anti-MrTV therapies.

Dietary quercetin protects Cherax quadricarinatus against white spot syndrome virus infection.

Quercetin is a plant flavonoid with a molecular formula C15H10O7. It has antioxidant, anti-inflammatory, antibacterial, and anti-apoptotic effects in animals. We used red claw crayfish (Cherax quadricarinatus) infected with white spot syndrome virus (WSSV) to investigate quercetin's effects on innate immunity of crustaceans. Quercetin supplementation significantly reduced the mortality of crayfish caused by WSSV infection and the number of VP28 copies in WSSV-infected crayfish. Quantitative real-time PCR analysis showed that dietary quercetin supplementation increased the expression of immune-related genes, like JAK, STAT and ALF. Quercetin supplementation affected the activity of six immune-related enzymes and increased the total number of hemocytes in crayfish. It also significantly reduced the rate of hemocyte apoptosis in both WSSV-infected and uninfected crayfish. These results demonstrate the potential for commercial use of quercetin for the prevention of WSSV disease in crustaceans.

Dietary glycerol monolaurate protects Cherax quadricarinatus against white spot syndrome virus infection.

Glycerol monolaurate (GML), one of the medium-chain fatty acid esters, is often used as an emulsifier or preservative. Its biological functions include antibacterial and antiviral activities. In this study, we examined the effects of dietary GML on the resistance of the red claw crayfish to WSSV infection. Crayfish fed with 4 g/kg GML showed higher survival rate and lower WSSV copy numbers than the control after WSSV infection. A RT-qPCR analysis showed that GML supplementation enhanced the expression of immune-related genes, especially JAK and caspase. Our data indicate that GML affects the immune parameters of crayfish, including the total hemocyte counts and phenoloxidase, acid phosphatase, superoxide dismutase, lysozyme, and peroxidase activities. After treatment with GML, the apoptosis of hemocytes increased significantly in both WSSV-infected and uninfected crayfish. In summary, GML reduced the mortality of WSSV-infected crayfish, perhaps by modulating the innate immunity of the crayfish. Our study shows that GML can be used to induce the innate immunity and enhance the immune protection of the red claw crayfish against WSSV infection, either therapeutically or as a preventive measure.

Investigation of putative antimicrobial peptides in Carassius gibel, revealing a practical approach to screening antimicrobials.

Antimicrobial peptides (AMPs) and their mimics are rapidly gaining attention as a new class of antimicrobials due to their clinical potential. AMPs are widely distributed throughout nature and participate in the innate host defense. In this study, 18 AMPs, including 3 ß-defensins, 3 hepcidins, 4 liver-expressed antimicrobial peptide 2 (LEAP-2) compounds, 4 g-type lysozymes, 2 c-type lysozymes, and 2 NK-lysins, were identified from the genome of Carassius auratus by a homologous search and were further classified based on their fundamental structural features and molecular phylogeny. C. auratus AMPs were found to be ubiquitously distributed in all tested tissues and showed similar expression profiles, with the exception of ß-defensins, when RT-qPCR was used to investigate the tissue distribution of AMPs in healthy Carassius gibel. In addition, the expression levels of NK-lysin genes in the tested tissues tended to be upregulated upon bacterial and viral infection when representative NK-lysins were chosen to examine their relative expression levels in various tissues. Importantly, the synthetic peptide caNKL2102-119, which targets the functional domain of saposin B in caNK-lysins, could effectively counter Aeromonas hydrophila, Staphylococcus aureus, and Escherichia coli with minimum inhibitory concentration (MIC) values of 3-6 µg/mL, as well as inhibit the proliferation of spring viraemia of carp virus (SVCV). These results provide potential targets for antibiotic-free breeding in the aquaculture industry.

Establishment and characterization of a spinal cord tissue cell line from mandarin fish, Siniperca chuatsi and its susceptibility to several viruses.

In this study, we established and characterized a continuous cell line from the spinal cord tissue of mandarin fish, Siniperca chuatsi and assessed its susceptibility to infectious spleen and kidney necrosis virus (ISKNV), Siniperca chuatsi ranavirus (SCRaV) and Siniperca chuatsi rhabdovirus (SCRV). The cell line, named SCC, has been successively cultured up to 40 passages. The optimal growing conditions of SCC cells were in Leibovitz's L-15 medium supplemented with 20% foetal bovine serum (FBS) at 28°C. Karyotype analysis demonstrated 48 normal diploid chromosomes in the cells. The identity of S. chuatsi origin of SCC cells was confirmed by partial sequencing of the 16S rRNA and cytochrome oxidase I (COI) genes. Infection susceptibility assessment showed that ISKNV, SCRIV and SCRV and can be stably produced and transmitted in SCC cells, and the replication efficiency of ISKNV, SCRaV and SCRV ranged from 107.4 to 109.6 TCID50 /ml. In addition, transmission electron microscopy analysis of ISKNV, SCRAV and SCRV infected SCC cells showed numerous viral particles. In conclusion, the newly established SCC cells provide an important tool for isolation and production of viruses, as well as for molecular and cell biology studies.

Morphological, histological and molecular characterization of Myxidium cf. rhodei infecting the kidney of Rutilus rutilus.

In the present study, we provide supplementary data for Myxidium cf. rhodei Léger, 1905 based on morphological, histological and molecular characterization. M. cf. rhodei was observed in the kidneys of 918 out of 942 (97%) roach Rutilus rutilus (Linnaeus, 1758). Myxospores of M. cf. rhodei were fusiform with pointed ends, measuring 12.7 ± 0.1 SD (11.8-13.4) µm in length and 4.6 ± 0.1 (3.8-5.4) µm in width. Two similar pear-shaped polar capsules were positioned at either ends of the longitudinal axis of the myxospore: each of these capsules measured 4.0 ± 0.1 (3.1-4.7) µm in length and 2.8 ± 0.1 (2.0-4.0) µm in width. Polar filaments were coiled into 4 to 5 turns. Approximately 18-20 longitudinal straight ridges were observed on the myxospore surface. The suture line was straight and distinctive, running near the middle of the valves. Histologically, the plasmodia of the present species were found in the Bowman's capsules, and rarely in the interstitium of the host. Phylogenetic analysis revealed that M. cf. rhodei was sister to M. anatidum in the Myxidium clade including most Myxidium species from freshwater hosts.

Proliferation dynamics of WSSV in crayfish, Procambarus clarkii, and the host responses at different temperatures.

The replication profile of white spot syndrome virus (WSSV) in crayfish, Procambarus clarkii, at different water temperature was investigated in this study. The WSSV detections were negative at 15 ± 1°C, and the natural infection ratio increased at 19 ± 1°C (24.2% ± 2.25%), reached 100% at 25 ± 1°C and decreased at 30 ± 1°C (93.2% ± 3.37%). The WSSV genome copies number was much higher at 25 ± 1°C (≥5 × 106.45 ± 0.35 /mg) than at 15 ± 1°C (≤5 × 101.13 ± 0.12 /mg), 19 ± 1°C (≤5 × 102.74 ± 0.48 /mg) and 32 ± 1°C (≤5 × 103.18 ± 0.27 /mg). Meanwhile, the significant transcription signals of immediate early gene ie1 and late gene vp28 and a large number of virus particles were detected in epitheliums of stomach, gut and gill, hepatopancreas, heart and muscle cells at 25 ± 1°C by using in situ hybridization (ISH) and transmission electron microscopy. The experimental infection of P. clarkii with WSSV infection showed reduced mortality and lower virus copies number at 19 ± 1°C (23.51% ± 0.84%, ≤5 × 103.41 ± 0.11 /mg) and 32 ± 1°C (38.42% ±  1.21%, ≤5 × 103.72 ± 0.13 /mg) compared to 25 ± 1°C (100%, ≥5 × 104.99 ± 0.24 /mg). The water temperature regulated the transcription of immune-related genes (crustin2, prophenoloxidase (proPO) and heat shock protein70 (Hsp70)), with some differences between WSSV treatments and control treatments. These results demonstrate that water temperature has effect on WSSV proliferation, which may due to transcriptional response of immune-related genes to temperature.

Influences of nitrite on paracetamol degradation in dielectric barrier discharge reactor.

The frequent detection of paracetamol in natural water increased environmental concerns. The dielectric barrier discharge (DBD) technology is an effective paracetamol removing method, however, this research showed that the removal of paracetamol using DBD technology at 30 min dropped from 100% to 53.3% as the initial paracetamol concentration increased from 10 mg/L to 100 mg/L, due to the formation of more competitive intermediate products at higher paracetamol concentration. The removal of TOC was found to be much slower than that of paracetamol, as paracetamol was removed completely after 5 min treatment, the removal rate of TOC was 46.3% after 20 min treatment under 500 W discharge power and 50 mL/min air flow rate. The orthogonal experiment showed that the removal of TOC was significantly influenced by the treatment time, discharge power and recirculating flow rate, while less influenced by the discharge frequency. In the removal process of paracetamol, nitrite ion that generated during DBD treatment reacted with paracetamol to form an intermediate product of 3-nitro-4-acetamidophenol. The presence of nitrite ion retarded the removal of 3-nitro-4-acetamidophenol and thus the TOC, however, the nitrate ion did not. The degradation of paracetamol followed a sequence of 3-nitro-4-acetamidophenol, nitrosophenol/acetamide, N-methylacetamide, acetamide and small molecule organic acids in the DBD reactor, and these intermediates were finally oxidized to CO2, H2O and NO3-.

A pattern learning-based method for temporal expression extraction and normalization from multi-lingual heterogeneous clinical texts.

BACKGROUND: Temporal expression extraction and normalization is a fundamental and essential step in clinical text processing and analyzing. Though a variety of commonly used NLP tools are available for medical temporal information extraction, few work is satisfactory for multi-lingual heterogeneous clinical texts. METHODS: A novel method called TEER is proposed for both multi-lingual temporal expression extraction and normalization from various types of narrative clinical texts including clinical data requests, clinical notes, and clinical trial summaries. TEER is characterized as temporal feature summarization, heuristic rule generation, and automatic pattern learning. By representing a temporal expression as a triple , TEER identifies temporal mentions M, assigns type attributes A to M, and normalizes the values of M into formal representations N. RESULTS: Based on two heterogeneous clinical text datasets: 400 actual clinical requests in English and 1459 clinical discharge summaries in Chinese. TEER was compared with six state-of-the-art baselines. The results showed that TEER achieved a precision of 0.948 and a recall of 0.877 on the English clinical requests, while a precision of 0.941 and a recall of 0.932 on the Chinese discharge summaries. CONCLUSIONS: An automated method TEER for multi-lingual temporal expression extraction was presented. Based on the two datasets containing heterogeneous clinical texts, the comparison results demonstrated the effectiveness of the TEER method in multi-lingual temporal expression extraction from heterogeneous narrative clinical texts.

Correction to: A pattern learning-based method for temporal expression extraction and normalization from multi-lingual heterogeneous clinical texts.

After publication of the original article [1] it was noted that the captions relating to Figs. 2 and 3 had been interchanged.

Bistatic ISAR Imaging with a V-FM Waveform Based on a Dual-Channel-Coupled 2D-CS Algorithm.

Due to the sparsity of the space distribution of point scatterers and radar echo data, the theory of Compressed Sensing (CS) has been successfully applied in Inverse Synthetic Aperture Radar (ISAR) imaging, which can recover an unknown sparse signal from a limited number of measurements by solving a sparsity-constrained optimization problem. In this paper, since the V style modulation(V-FM) signal can mitigate the ambiguity apparent in range and velocity, the dual-channel, two-dimension, compressed-sensing (2D-CS) algorithm is proposed for Bistatic ISAR (Bi-ISAR) imaging, which directly deals with the 2D signal model for image reconstruction based on solving a nonconvex optimization problem. The coupled 2D super-resolution model of the target's echoes is firstly established; then, the 2D-SL0 algorithm is applied in each channel with different dictionaries, and the final image is obtained by synthesizing the two channels. Experiments are used to test the robustness of the Bi-ISAR imaging framework with the two-dimensional CS method. The results show that the framework is capable accurately reconstructing the Bi-ISAR image within the conditions of low SNR and low measured data.

Proteomic analysis of differentially expressed proteins in the two developmental stages of Ichthyophthirius multifiliis.

Ichthyophthirius is a severe disease of farmed freshwater fish caused by the parasitic ciliate Ichthyophthirius multifiliis (Ich). This disease can lead to considerable economic loss, but the protein profiles in different developmental stages of the parasite remain unknown. In the present study, proteins from trophonts and theronts of Ich were identified by isobaric tags for relative and absolute quantitation (iTRAQ). A total of 2300 proteins were identified in the two developmental stages, of which 1520 proteins were differentially expressed. Among them, 84 proteins were uniquely expressed in the theronts stage, while 656 proteins were expressed only in trophonts. The differentially expressed proteins were catalogued (assorted) to various functions of Ich life cycle, including biological process, cellular component, and molecular function that occur at distinct stages. Using a 1.5-fold change in expression as a physiologically significant benchmark, a lot of differentially expressed proteins were reliably quantified by iTRAQ analysis. Two hundred forty upregulated and 57 downregulated proteins in the trophonts stage were identified as compared with theronts. The identified proteins were involved in various functions of the I. multifiliis life cycle, including binding, catalytic activity, structural molecule activity, and transporter activity. Further investigation of the transcriptional levels of periplasmic immunogenic protein, transketolase, zinc finger, isocitrate dehydrogenase, etc., from the different protein profiles using quantitative RT-PCR showed identical results to the iTRAQ analysis. This work provides an effective resource to further our understanding of Ich biology, and lays the groundwork for the identification of potential drug targets and vaccines candidates for the control of this devastating fish pathogen.

Live recombinant Lactococcus lactis vaccine expressing immobilization antigen (i-Ag) for protection against Ichthyophthirius multifiliis in goldfish.

The parasite Ichthyophthirius multifiliis (Ich) has been reported in various freshwater fishes worldwide and results in severe losses to both food and aquarium fish production. Lactobacillus strains have a number of properties that make them attractive candidates as delivery vehicles for the presentation to the mucosa of compounds with pharmaceutical interest, in particular vaccines. Here, the present study was conducted to evaluate a live recombinant Lactococcus lactis vaccine expressing immobilization antigen (IAG-52X) in protection against I. multifiliis. A 1266 bp gene fragment containing a potential antigenic epitope of the 48 kDa immobilization antigen of I. multifiliis was assembled from six synthetic ohgonucleotides and cloned into pSIP409 and electrotransformed into Lactobacillus plantarum NC8. The recombinant vaccine candidate was then orally fed into goldfish. The expression of immune-related genes: complement component 3 (C3), MHC I, IgM gene in blood from goldfish at different time points after immunization were evaluated. Immunized fish were than challenged with a lethal dose of infectious I. multifiliis. The cumulative mortality and relative percentage survival (RPS) were also determined. Our results showed that the antibody level in the blood and skin of the immunized fish was statistically significant (P < 0.05) in relation to the control groups. Goldfish orally immunized with NC8-pSIP409- IAG-52X had high serum antibody titers that ranged from 32 to 256 after 28d post immunization, while fish fed with NC8-pSIP409 or PBS had no detectable immobilizing antibody response. Expression of IgM, C3, MHC I genes in the group immunized with IAG-52X were significantly (P < 0.05) up regulated as compared with control group, indicating that different immune cells were actively involved in cellular immune response. The results showed that the average survival rate of fish orally immunized with 108 and 106NC8-pSIP409-IAG-52X was 60% and 50% respectively. Therefore, NC8-pSIP409-IAG-52X could become a promising oral vaccine candidate against I. multifiliis.

Isolation and Characterization of a Novel Dicistrovirus Associated with Moralities of the Great Freshwater Prawn, Macrobrachium rosenbergii.

The giant freshwater prawn, Macrobrachium rosenbergii, is an economically important crustacean and is farmed in many countries. Since 2009, a larval mortality syndrome of M. rosenbergii has broken out and spread widely in the main breeding area, including Zhejiang, Jiangsu, Guangxi, and Guangdong Provinces in mainland China. A novel virus, named Macrobrachium rosenbergii Taihu virus (MrTV), was isolated from the moribund larvae and was determined to be the causative agent of the M. rosenbergii larval mortality syndrome by experimental infection. Further genomic sequencing suggested that the MrTV genome is monopartite, 10,303 nt in length, and dicistronic with two non-overlapping open reading frames (ORFs) separated by an intergenic region (IGR) and flanked by untranslated regions (UTRs). Phylogenetic analysis using the full-length genomic sequence and the putative amino acid sequences of the capsid protein revealed that MrTV was more closely related to the taura syndrome virus (TSV) than to any other viruses. According to these molecular features, we proposed that MrTV is a new species in the genus Aparavirus, family Dicistroviridae. These results may shed light on controlling larval mortality syndrome in M. rosenbergii.

Evaluation of nystatin isolated from Streptomyces griseus SDX-4 against the ciliate, Ichthyophthirius multifiliis.

The present study was conducted to evaluate the in vitro and in vivo antiparasitic efficacy of active compounds from the bacterial extracellular products of Streptomyces griseus SDX-4 against Ichthyophthirius multifiliis. Bioassay-guided fractionation and isolation of compounds with antiparasitic activity were performed on n-butanol extract of S. griseus yielding a pure bioactive compound, nystatin (Nys), identified by comparing spectral data (EI-MS, (1)H NMR, and (13)C NMR) with literature values. Results from in vitro antiparasitic assays revealed that Nys could be 100% effective against I. multifiliis theronts and encysted tomonts at the concentration of 6.0 mg L(-1), with the median effective concentration (EC50) values of 3.1 and 2.8 mg L(-1) for theronts and encysted tomonts (4 h), respectively. Results of in vivo test demonstrated that the number of I. multifiliis trophonts on the gold fish treated with Nys was markedly lower than the control group at 10 days after exposed to theronts (p < 0.05). In the control group, 85.7% mortality was observed owing to heavy I. multifiliis infection at 10 days after the exposure. On the other hand, only 23.8% mortality owing to parasite infection was recorded in the groups treated with the Nys (4.0 and 6.0 mg L(-1)). In addition, our results showed that the survival and reproduction of I. multifiliis tomont exited from the fish were significantly reduced after treated with the 6.0 mg L(-1) Nys. The median lethal dose (LD50) of Nys for goldfish was 16.8 mg L(-1). This study firstly demonstrated that Nys has potent antiparasitic efficacy against I. multifiliis, and it can be a good candidate drug for chemotherapy and control of I. multifiliis infections.

[Molecular mechanisms of quinolone resistance in Aeromonas hydrophilia].

OBJECT: To study the resistance mechanisms to quinolones in Aeromonas hydrohila isolated from aquatic animals. METHODS: The drug-resistant spectrum of 23 strains was determined. Quinolone-resistance determining regions of gyrA and parC genes in both screened and in-vitro induction drug-resistant strains were analyzed. Then the detection of quinolone drugs relative efflux pump genes qepA, oqxA and mdfA was performed. The qnrA, qnrB, qnrC, qnrD and qnrS genes were also analyzed at the same time. RESULTS: All organisms were resistant to more than 5 drugs; 39.1% (9/23) of the isolates were quinolone resistant, of which 55.6% (5/9) were enrofloxacin resistant. All the enrofloxacin-resistant isolates harbored qnrS gene, but none of the enrofloxacin-resistant strains harbored qnrA, qnrB, qnrC , qnrD genes and the efflux pump genes of qepA, oqxA and mdfA. AH19 possessed the gyrA and parC genes double mutation, plasmid-mediated quinolone resistance gene qnrS and efflux pump, 3 drug resistance mechanisms simultaneously, while the two drug-resistant mechanisms of AH4, AH7 and AH20 were gyrA and parC genes double mutation and qnrS gene. GyrA gene mutation and qnrS gene occurred in AH6. Compared to the strain ATCC7966, the in-vitro induction drug-resistant strain ATCC7966-QR had both the gyrA and parC genes mutation. CONCLUSION: The mechanisms of resistance to quinolones in the A. hydrophila isolates of this study mainly depended on the existence of plasmid-mediated gene qnrS and the variation of the target site of quinolone drugs, whereas, the drug resistance mechanism relying on the efflux pump system only existed in individual strains.

Controllable synthesis of electric double-layer capacitance and pseudocapacitance coupled porous carbon cathode material for zinc-ion hybrid capacitors.

The designability of the porous structure of carbon material makes it a popular material for zinc-ion hybrid capacitors (ZIHCs). However, the micropore confinement effect leads to sluggish kinetics and is not well resolved yet. In this work, a pore-size controllable carbon material was designed to enhance ion accessibility. The experimental and calculated results revealed that suitable pore sizes and defects were beneficial to ion transfer/adsorption. Meanwhile, oxygen-containing functional groups could introduce a pseudocapacitance reaction. Its large specific surface area and interconnecting network structure could shorten the ion/electron transfer length to reach high ion adsorption capacity and fast kinetic behavior. When used as a zinc-ion hybrid capacitor cathode material, it showed 9.9 kW kg-1 power density and 100 W h kg-1 energy density. Even at 5 A g-1, after 50 000 cycles, there was still 93% capacity retention. Systemic ex situ characterization and first-principles calculations indicated that the excellent electrochemical performance is attributed to the electric double layer capacitance (EDLC) - pseudocapacitance coupled mechanism via the introduction of an appropriate amount of oxygen-containing functional groups. This work provides a robust design for pore engineering and mechanistic insights into rapid zinc-ion storage in carbon materials.

Comparison of the efficacy of Aeromonas veronii ΔhisJ vaccine in Carassius auratus via different immunization routes.

Introdction: Aeromonas veronii is a significant pathogen to various aquatic life. Infections in fish can lead to high mortality rates, causing substantial economic losses in aquaculture. Vaccination is proposed as a substitute for antibiotics in aquaculture to decrease disease-related mortality and morbidity. Our study previously constructed a hisJ-deleted strain of A. veronii, which provided protective effect to Loach. Methods: To further assess the vaccine's applicability, this study evaluated its genetic stability and safety, and the immune protective effects in Carassius auratus through four distinct administration routes: intraperitoneal injection, intramuscular injection, oral administration, and immersion, to determine the efficacy of these administration routes. Results: The results showed that the vaccine remained genetically stable after 45 generations. Immunization via these administration routes was safe for Carassius auratus, with intraperitoneal and intramuscular injections causing stronger adverse reactions. Immersion immunization resulted in mild adverse reactions, and no significant adverse reactions were observed following oral immunization. Immunizing Carassius auratus at safe concentrations via these routes enhanced the phagocytic activity in serum, increased the levels of non-specific immune-related enzymes (ACP, AKP, C3, C4, LZM, SOD, and IgM), and improved specific serum antibody levels. It also elevated levels of cytokines related to inflammatory responses (IL-1ß, IL-10, TNF-α, TGF-ß) in organ tissues (liver, spleen, kidney, mid-post intestine, and gills). The survival rates of Carassius auratus were measured after challenging with the virulent strain A. veronii TH0426, resulting in the relative survival rates of 64% for Intraperitoneal vaccine group, 56% for Intramuscular vaccine group, 52% for oral vaccine group, and 48% for immersion vaccine group. Analysis of bacterial load in the liver, spleen, and kidney post-challenge showed a decreasing trend in the control group, indicating that the vaccine strain ΔhisJ could gradually restrict the rapid proliferation of bacteria in these tissues, thereby providing a certain level of immune protection against A. veronii. Discussion: In brief, the vaccine strain ΔhisJ can serve as a safe live attenuated vaccine for Carassius auratus, and this study lays the foundation for the development of live attenuated vaccines against Aeromonas veronii.

Downregulation of OATP2B1 by proinflammatory cytokines leads to 5-ASA hyposensitivity in Ulcerative colitis.

5-Aminosalicylic acid (5-ASA) is a first-line agent in both remission and maintenance therapy for ulcerative colitis (UC). However, the mucosal concentration of 5-ASA was significantly lower in patients with severe histological inflammation, which further led to a poor response to 5-ASA treatment. Our study aimed to clarify the mechanism of 5-ASA uptake into colonic epithelial cells and to further explore the reason for the decreased colonic mucosal 5-ASA concentration in UC patients. Our results demonstrated that the colonic 5-ASA concentration was notably reduced in DSS-induced colitis mice and inversely correlated with colonic inflammation. 5-ASA was not a substrate of carnitine/organic cation transporter 1/2 (OCTN1/2) or multidrug resistance protein 1 (MDR1), whereas organic anion transporting polypeptide 2B1 (OATP2B1) and sodium-coupled monocarboxylate transporter 1 (SMCT1) mediated the uptake of 5-ASA, with a greater contribution from OATP2B1 than SMCT1. Inhibitors and siRNAs targeting OATP2B1 significantly reduced 5-ASA absorption in colonic cell lines. Moreover, OATP2B1 expression was dramatically downregulated in colon tissues from UC patients and dextran sodium sulfate (DSS)-induced colitis mice, and was also negatively correlated with colonic inflammation. Mechanistically, mixed proinflammatory cytokines downregulated the expression of OATP2B1 in a time- and concentration-dependent manner through the hepatocyte nuclear factor 4 α (HNF4α) pathway. In conclusion, OATP2B1 was the pivotal transporter involved in colonic 5-ASA uptake, which indicated that inducing OATP2B1 expression may be a strategy to promote 5-ASA uptake and further improve the concentration and anti-inflammatory efficacy of 5-ASA in UC.

Biological characteristics and pathogenicity comparison of Nocardia seriolae isolated from Micropterus salmoides and Channa argus.

Nocardia seriolae is the primary pathogen causing nocardiosis in various fish species, leads to significant economic losses in the aquaculture industry. In this study, 10 bacterial strains isolated from Micropterus salmoides and Channa argus infected with nocardiosis, were identified as N. seriolae by physiological and biochemical identification, as well as 16S rDNA sequencing. Moreover, the key virulence-related genes such as ESX-1, T7SS-2, T7SS-3, EspG1, sodC, sod2 and ESAT6 were all positive, and showing high homology among different strains. Pathogenicity testing revealed mortality rates ranging from 70 to 100%, accompanied by the presence of white nodules in the viscera of deceased fish. The drug sensitivity test demonstrated that LY21811, the most lethal strain, exhibited high sensitivity to nine types of antibiotics, including azithromycin, doxycycline, florfenicol and compound sulfamethoxazole, yet showed complete resistance to ß-lactam antibiotics. Additionally, the tannic acid also demonstrated potent inhibitory effects against LY21811, with a minimum inhibitory concentration of 0.0625 mg/mL. These results showed that N. seriolae originated from M. salmoides and C. argus in Zhejiang Province were highly conserved, demonstrating a high homogeneity in genetic characteristics, pathogenicity and antimicrobial susceptibilities. These results provide a foundation for further research on the pathogenic characteristics and disease prevention of N. seriolae infections.